xref: /freebsd/sys/netinet/tcp_stacks/rack.c (revision e17f5b1d) 
1 /*-
2  * Copyright (c) 2016-2020 Netflix, Inc.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  *
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "opt_inet.h"
31 #include "opt_inet6.h"
32 #include "opt_ipsec.h"
33 #include "opt_tcpdebug.h"
34 #include "opt_ratelimit.h"
35 #include "opt_kern_tls.h"
36 #include <sys/param.h>
37 #include <sys/arb.h>
38 #include <sys/module.h>
39 #include <sys/kernel.h>
40 #ifdef TCP_HHOOK
41 #include <sys/hhook.h>
42 #endif
43 #include <sys/lock.h>
44 #include <sys/malloc.h>
45 #include <sys/lock.h>
46 #include <sys/mutex.h>
47 #include <sys/mbuf.h>
48 #include <sys/proc.h>		/* for proc0 declaration */
49 #include <sys/socket.h>
50 #include <sys/socketvar.h>
51 #ifdef KERN_TLS
52 #include <sys/ktls.h>
53 #endif
54 #include <sys/sysctl.h>
55 #include <sys/systm.h>
56 #ifdef STATS
57 #include <sys/qmath.h>
58 #include <sys/tree.h>
59 #include <sys/stats.h> /* Must come after qmath.h and tree.h */
60 #else
61 #include <sys/tree.h>
62 #endif
63 #include <sys/refcount.h>
64 #include <sys/queue.h>
65 #include <sys/tim_filter.h>
66 #include <sys/smp.h>
67 #include <sys/kthread.h>
68 #include <sys/kern_prefetch.h>
69 #include <sys/protosw.h>
70 
71 #include <vm/uma.h>
72 
73 #include <net/route.h>
74 #include <net/route/nhop.h>
75 #include <net/vnet.h>
76 
77 #define TCPSTATES		/* for logging */
78 
79 #include <netinet/in.h>
80 #include <netinet/in_kdtrace.h>
81 #include <netinet/in_pcb.h>
82 #include <netinet/ip.h>
83 #include <netinet/ip_icmp.h>	/* required for icmp_var.h */
84 #include <netinet/icmp_var.h>	/* for ICMP_BANDLIM */
85 #include <netinet/ip_var.h>
86 #include <netinet/ip6.h>
87 #include <netinet6/in6_pcb.h>
88 #include <netinet6/ip6_var.h>
89 #include <netinet/tcp.h>
90 #define	TCPOUTFLAGS
91 #include <netinet/tcp_fsm.h>
92 #include <netinet/tcp_log_buf.h>
93 #include <netinet/tcp_seq.h>
94 #include <netinet/tcp_timer.h>
95 #include <netinet/tcp_var.h>
96 #include <netinet/tcp_hpts.h>
97 #include <netinet/tcp_ratelimit.h>
98 #include <netinet/tcpip.h>
99 #include <netinet/cc/cc.h>
100 #include <netinet/tcp_fastopen.h>
101 #include <netinet/tcp_lro.h>
102 #ifdef NETFLIX_SHARED_CWND
103 #include <netinet/tcp_shared_cwnd.h>
104 #endif
105 #ifdef TCPDEBUG
106 #include <netinet/tcp_debug.h>
107 #endif				/* TCPDEBUG */
108 #ifdef TCP_OFFLOAD
109 #include <netinet/tcp_offload.h>
110 #endif
111 #ifdef INET6
112 #include <netinet6/tcp6_var.h>
113 #endif
114 
115 #include <netipsec/ipsec_support.h>
116 
117 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
118 #include <netipsec/ipsec.h>
119 #include <netipsec/ipsec6.h>
120 #endif				/* IPSEC */
121 
122 #include <netinet/udp.h>
123 #include <netinet/udp_var.h>
124 #include <machine/in_cksum.h>
125 
126 #ifdef MAC
127 #include <security/mac/mac_framework.h>
128 #endif
129 #include "sack_filter.h"
130 #include "tcp_rack.h"
131 #include "rack_bbr_common.h"
132 
133 uma_zone_t rack_zone;
134 uma_zone_t rack_pcb_zone;
135 
136 #ifndef TICKS2SBT
137 #define	TICKS2SBT(__t)	(tick_sbt * ((sbintime_t)(__t)))
138 #endif
139 
140 struct sysctl_ctx_list rack_sysctl_ctx;
141 struct sysctl_oid *rack_sysctl_root;
142 
143 #define CUM_ACKED 1
144 #define SACKED 2
145 
146 /*
147  * The RACK module incorporates a number of
148  * TCP ideas that have been put out into the IETF
149  * over the last few years:
150  * - Matt Mathis's Rate Halving which slowly drops
151  *    the congestion window so that the ack clock can
152  *    be maintained during a recovery.
153  * - Yuchung Cheng's RACK TCP (for which its named) that
154  *    will stop us using the number of dup acks and instead
155  *    use time as the gage of when we retransmit.
156  * - Reorder Detection of RFC4737 and the Tail-Loss probe draft
157  *    of Dukkipati et.al.
158  * RACK depends on SACK, so if an endpoint arrives that
159  * cannot do SACK the state machine below will shuttle the
160  * connection back to using the "default" TCP stack that is
161  * in FreeBSD.
162  *
163  * To implement RACK the original TCP stack was first decomposed
164  * into a functional state machine with individual states
165  * for each of the possible TCP connection states. The do_segement
166  * functions role in life is to mandate the connection supports SACK
167  * initially and then assure that the RACK state matches the conenction
168  * state before calling the states do_segment function. Each
169  * state is simplified due to the fact that the original do_segment
170  * has been decomposed and we *know* what state we are in (no
171  * switches on the state) and all tests for SACK are gone. This
172  * greatly simplifies what each state does.
173  *
174  * TCP output is also over-written with a new version since it
175  * must maintain the new rack scoreboard.
176  *
177  */
178 static int32_t rack_tlp_thresh = 1;
179 static int32_t rack_tlp_limit = 2;	/* No more than 2 TLPs w-out new data */
180 static int32_t rack_tlp_use_greater = 1;
181 static int32_t rack_reorder_thresh = 2;
182 static int32_t rack_reorder_fade = 60000;	/* 0 - never fade, def 60,000
183 						 * - 60 seconds */
184 /* Attack threshold detections */
185 static uint32_t rack_highest_sack_thresh_seen = 0;
186 static uint32_t rack_highest_move_thresh_seen = 0;
187 
188 static int32_t rack_pkt_delay = 1;
189 static int32_t rack_early_recovery = 1;
190 static int32_t rack_send_a_lot_in_prr = 1;
191 static int32_t rack_min_to = 1;	/* Number of ms minimum timeout */
192 static int32_t rack_verbose_logging = 0;
193 static int32_t rack_ignore_data_after_close = 1;
194 static int32_t rack_enable_shared_cwnd = 0;
195 static int32_t rack_limits_scwnd = 1;
196 static int32_t rack_enable_mqueue_for_nonpaced = 0;
197 static int32_t rack_disable_prr = 0;
198 static int32_t use_rack_rr = 1;
199 static int32_t rack_non_rxt_use_cr = 0; /* does a non-rxt in recovery use the configured rate (ss/ca)? */
200 static int32_t rack_persist_min = 250;	/* 250ms */
201 static int32_t rack_persist_max = 2000;	/* 2 Second */
202 static int32_t rack_sack_not_required = 0;	/* set to one to allow non-sack to use rack */
203 static int32_t rack_hw_tls_max_seg = 3; /* 3 means use hw-tls single segment */
204 static int32_t rack_default_init_window = 0; 	/* Use system default */
205 static int32_t rack_limit_time_with_srtt = 0;
206 static int32_t rack_hw_pace_adjust = 0;
207 /*
208  * Currently regular tcp has a rto_min of 30ms
209  * the backoff goes 12 times so that ends up
210  * being a total of 122.850 seconds before a
211  * connection is killed.
212  */
213 static uint32_t rack_def_data_window = 20;
214 static uint32_t rack_goal_bdp = 2;
215 static uint32_t rack_min_srtts = 1;
216 static uint32_t rack_min_measure_usec = 0;
217 static int32_t rack_tlp_min = 10;
218 static int32_t rack_rto_min = 30;	/* 30ms same as main freebsd */
219 static int32_t rack_rto_max = 4000;	/* 4 seconds */
220 static const int32_t rack_free_cache = 2;
221 static int32_t rack_hptsi_segments = 40;
222 static int32_t rack_rate_sample_method = USE_RTT_LOW;
223 static int32_t rack_pace_every_seg = 0;
224 static int32_t rack_delayed_ack_time = 200;	/* 200ms */
225 static int32_t rack_slot_reduction = 4;
226 static int32_t rack_wma_divisor = 8;		/* For WMA calculation */
227 static int32_t rack_cwnd_block_ends_measure = 0;
228 static int32_t rack_rwnd_block_ends_measure = 0;
229 
230 static int32_t rack_lower_cwnd_at_tlp = 0;
231 static int32_t rack_use_proportional_reduce = 0;
232 static int32_t rack_proportional_rate = 10;
233 static int32_t rack_tlp_max_resend = 2;
234 static int32_t rack_limited_retran = 0;
235 static int32_t rack_always_send_oldest = 0;
236 static int32_t rack_tlp_threshold_use = TLP_USE_TWO_ONE;
237 
238 static uint16_t rack_per_of_gp_ss = 250;	/* 250 % slow-start */
239 static uint16_t rack_per_of_gp_ca = 200;	/* 200 % congestion-avoidance */
240 static uint16_t rack_per_of_gp_rec = 200;	/* 200 % of bw */
241 
242 /* Probertt */
243 static uint16_t rack_per_of_gp_probertt = 60;	/* 60% of bw */
244 static uint16_t rack_per_of_gp_lowthresh = 40;	/* 40% is bottom */
245 static uint16_t rack_per_of_gp_probertt_reduce = 10; /* 10% reduction */
246 static uint16_t rack_atexit_prtt_hbp = 130;	/* Clamp to 130% on exit prtt if highly buffered path */
247 static uint16_t rack_atexit_prtt = 130;	/* Clamp to 100% on exit prtt if non highly buffered path */
248 
249 static uint32_t rack_max_drain_wait = 2;	/* How man gp srtt's before we give up draining */
250 static uint32_t rack_must_drain = 1;		/* How many GP srtt's we *must* wait */
251 static uint32_t rack_probertt_use_min_rtt_entry = 1;	/* Use the min to calculate the goal else gp_srtt */
252 static uint32_t rack_probertt_use_min_rtt_exit = 0;
253 static uint32_t rack_probe_rtt_sets_cwnd = 0;
254 static uint32_t rack_probe_rtt_safety_val = 2000000;	/* No more than 2 sec in probe-rtt */
255 static uint32_t rack_time_between_probertt = 9600000;	/* 9.6 sec in us */
256 static uint32_t rack_probertt_gpsrtt_cnt_mul = 0;	/* How many srtt periods does probe-rtt last top fraction */
257 static uint32_t rack_probertt_gpsrtt_cnt_div = 0;	/* How many srtt periods does probe-rtt last bottom fraction  */
258 static uint32_t rack_min_probertt_hold = 200000;	/* Equal to delayed ack time */
259 static uint32_t rack_probertt_filter_life = 10000000;
260 static uint32_t rack_probertt_lower_within = 10;
261 static uint32_t rack_min_rtt_movement = 250;	/* Must move at least 250 useconds to count as a lowering */
262 static int32_t rack_pace_one_seg = 0;		/* Shall we pace for less than 1.4Meg 1MSS at a time */
263 static int32_t rack_probertt_clear_is = 1;
264 static int32_t rack_max_drain_hbp = 1;		/* Extra drain times gpsrtt for highly buffered paths */
265 static int32_t rack_hbp_thresh = 3;		/* what is the divisor max_rtt/min_rtt to decided a hbp */
266 
267 
268 /* Part of pacing */
269 static int32_t rack_max_per_above = 30;		/* When we go to increment stop if above 100+this% */
270 
271 /* Timely information */
272 /* Combine these two gives the range of 'no change' to bw */
273 /* ie the up/down provide the upper and lower bound  */
274 static int32_t rack_gp_per_bw_mul_up = 2;	/* 2% */
275 static int32_t rack_gp_per_bw_mul_down = 4;	/* 4% */
276 static int32_t rack_gp_rtt_maxmul = 3;		/* 3 x maxmin */
277 static int32_t rack_gp_rtt_minmul = 1;		/* minrtt + (minrtt/mindiv) is lower rtt */
278 static int32_t rack_gp_rtt_mindiv = 4;		/* minrtt + (minrtt * minmul/mindiv) is lower rtt */
279 static int32_t rack_gp_decrease_per = 20;	/* 20% decrease in multipler */
280 static int32_t rack_gp_increase_per = 2;	/* 2% increase in multipler */
281 static int32_t rack_per_lower_bound = 50;	/* Don't allow to drop below this multiplier */
282 static int32_t rack_per_upper_bound_ss = 0;	/* Don't allow SS to grow above this */
283 static int32_t rack_per_upper_bound_ca = 0;	/* Don't allow CA to grow above this */
284 static int32_t rack_do_dyn_mul = 0;		/* Are the rack gp multipliers dynamic */
285 static int32_t rack_gp_no_rec_chg = 1;		/* Prohibit recovery from reducing it's multiplier */
286 static int32_t rack_timely_dec_clear = 6;	/* Do we clear decrement count at a value (6)? */
287 static int32_t rack_timely_max_push_rise = 3;	/* One round of pushing */
288 static int32_t rack_timely_max_push_drop = 3;	/* Three round of pushing */
289 static int32_t rack_timely_min_segs = 4;	/* 4 segment minimum */
290 static int32_t rack_use_max_for_nobackoff = 0;
291 static int32_t rack_timely_int_timely_only = 0;	/* do interim timely's only use the timely algo (no b/w changes)? */
292 static int32_t rack_timely_no_stopping = 0;
293 static int32_t rack_down_raise_thresh = 100;
294 static int32_t rack_req_segs = 1;
295 
296 /* Weird delayed ack mode */
297 static int32_t rack_use_imac_dack = 0;
298 /* Rack specific counters */
299 counter_u64_t rack_badfr;
300 counter_u64_t rack_badfr_bytes;
301 counter_u64_t rack_rtm_prr_retran;
302 counter_u64_t rack_rtm_prr_newdata;
303 counter_u64_t rack_timestamp_mismatch;
304 counter_u64_t rack_reorder_seen;
305 counter_u64_t rack_paced_segments;
306 counter_u64_t rack_unpaced_segments;
307 counter_u64_t rack_calc_zero;
308 counter_u64_t rack_calc_nonzero;
309 counter_u64_t rack_saw_enobuf;
310 counter_u64_t rack_saw_enetunreach;
311 counter_u64_t rack_per_timer_hole;
312 
313 /* Tail loss probe counters */
314 counter_u64_t rack_tlp_tot;
315 counter_u64_t rack_tlp_newdata;
316 counter_u64_t rack_tlp_retran;
317 counter_u64_t rack_tlp_retran_bytes;
318 counter_u64_t rack_tlp_retran_fail;
319 counter_u64_t rack_to_tot;
320 counter_u64_t rack_to_arm_rack;
321 counter_u64_t rack_to_arm_tlp;
322 counter_u64_t rack_to_alloc;
323 counter_u64_t rack_to_alloc_hard;
324 counter_u64_t rack_to_alloc_emerg;
325 counter_u64_t rack_to_alloc_limited;
326 counter_u64_t rack_alloc_limited_conns;
327 counter_u64_t rack_split_limited;
328 
329 counter_u64_t rack_sack_proc_all;
330 counter_u64_t rack_sack_proc_short;
331 counter_u64_t rack_sack_proc_restart;
332 counter_u64_t rack_sack_attacks_detected;
333 counter_u64_t rack_sack_attacks_reversed;
334 counter_u64_t rack_sack_used_next_merge;
335 counter_u64_t rack_sack_splits;
336 counter_u64_t rack_sack_used_prev_merge;
337 counter_u64_t rack_sack_skipped_acked;
338 counter_u64_t rack_ack_total;
339 counter_u64_t rack_express_sack;
340 counter_u64_t rack_sack_total;
341 counter_u64_t rack_move_none;
342 counter_u64_t rack_move_some;
343 
344 counter_u64_t rack_used_tlpmethod;
345 counter_u64_t rack_used_tlpmethod2;
346 counter_u64_t rack_enter_tlp_calc;
347 counter_u64_t rack_input_idle_reduces;
348 counter_u64_t rack_collapsed_win;
349 counter_u64_t rack_tlp_does_nada;
350 counter_u64_t rack_try_scwnd;
351 
352 /* Counters for HW TLS */
353 counter_u64_t rack_tls_rwnd;
354 counter_u64_t rack_tls_cwnd;
355 counter_u64_t rack_tls_app;
356 counter_u64_t rack_tls_other;
357 counter_u64_t rack_tls_filled;
358 counter_u64_t rack_tls_rxt;
359 counter_u64_t rack_tls_tlp;
360 
361 /* Temp CPU counters */
362 counter_u64_t rack_find_high;
363 
364 counter_u64_t rack_progress_drops;
365 counter_u64_t rack_out_size[TCP_MSS_ACCT_SIZE];
366 counter_u64_t rack_opts_arry[RACK_OPTS_SIZE];
367 
368 static void
369 rack_log_progress_event(struct tcp_rack *rack, struct tcpcb *tp, uint32_t tick,  int event, int line);
370 
371 static int
372 rack_process_ack(struct mbuf *m, struct tcphdr *th,
373     struct socket *so, struct tcpcb *tp, struct tcpopt *to,
374     uint32_t tiwin, int32_t tlen, int32_t * ofia, int32_t thflags, int32_t * ret_val);
375 static int
376 rack_process_data(struct mbuf *m, struct tcphdr *th,
377     struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
378     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt);
379 static void
380 rack_ack_received(struct tcpcb *tp, struct tcp_rack *rack,
381     struct tcphdr *th, uint16_t nsegs, uint16_t type, int32_t recovery);
382 static struct rack_sendmap *rack_alloc(struct tcp_rack *rack);
383 static struct rack_sendmap *rack_alloc_limit(struct tcp_rack *rack,
384     uint8_t limit_type);
385 static struct rack_sendmap *
386 rack_check_recovery_mode(struct tcpcb *tp,
387     uint32_t tsused);
388 static void
389 rack_cong_signal(struct tcpcb *tp, struct tcphdr *th,
390     uint32_t type);
391 static void rack_counter_destroy(void);
392 static int
393 rack_ctloutput(struct socket *so, struct sockopt *sopt,
394     struct inpcb *inp, struct tcpcb *tp);
395 static int32_t rack_ctor(void *mem, int32_t size, void *arg, int32_t how);
396 static void
397 rack_set_pace_segments(struct tcpcb *tp, struct tcp_rack *rack, uint32_t line);
398 static void
399 rack_do_segment(struct mbuf *m, struct tcphdr *th,
400     struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
401     uint8_t iptos);
402 static void rack_dtor(void *mem, int32_t size, void *arg);
403 static void
404 rack_earlier_retran(struct tcpcb *tp, struct rack_sendmap *rsm,
405     uint32_t t, uint32_t cts);
406 static void
407 rack_log_alt_to_to_cancel(struct tcp_rack *rack,
408     uint32_t flex1, uint32_t flex2,
409     uint32_t flex3, uint32_t flex4,
410     uint32_t flex5, uint32_t flex6,
411     uint16_t flex7, uint8_t mod);
412 static void
413 rack_log_pacing_delay_calc(struct tcp_rack *rack, uint32_t len, uint32_t slot,
414    uint64_t bw_est, uint64_t bw, uint64_t len_time, int method, int line, struct rack_sendmap *rsm);
415 static struct rack_sendmap *
416 rack_find_high_nonack(struct tcp_rack *rack,
417     struct rack_sendmap *rsm);
418 static struct rack_sendmap *rack_find_lowest_rsm(struct tcp_rack *rack);
419 static void rack_free(struct tcp_rack *rack, struct rack_sendmap *rsm);
420 static void rack_fini(struct tcpcb *tp, int32_t tcb_is_purged);
421 static int
422 rack_get_sockopt(struct socket *so, struct sockopt *sopt,
423     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack);
424 static void
425 rack_do_goodput_measurement(struct tcpcb *tp, struct tcp_rack *rack,
426 			    tcp_seq th_ack, int line);
427 static uint32_t
428 rack_get_pacing_len(struct tcp_rack *rack, uint64_t bw, uint32_t mss);
429 static int32_t rack_handoff_ok(struct tcpcb *tp);
430 static int32_t rack_init(struct tcpcb *tp);
431 static void rack_init_sysctls(void);
432 static void
433 rack_log_ack(struct tcpcb *tp, struct tcpopt *to,
434     struct tcphdr *th);
435 static void
436 rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len,
437     uint32_t seq_out, uint8_t th_flags, int32_t err, uint32_t ts,
438     uint8_t pass, struct rack_sendmap *hintrsm, uint32_t us_cts);
439 static void
440 rack_log_sack_passed(struct tcpcb *tp, struct tcp_rack *rack,
441     struct rack_sendmap *rsm);
442 static void rack_log_to_event(struct tcp_rack *rack, int32_t to_num, struct rack_sendmap *rsm);
443 static int32_t rack_output(struct tcpcb *tp);
444 
445 static uint32_t
446 rack_proc_sack_blk(struct tcpcb *tp, struct tcp_rack *rack,
447     struct sackblk *sack, struct tcpopt *to, struct rack_sendmap **prsm,
448     uint32_t cts, int *moved_two);
449 static void rack_post_recovery(struct tcpcb *tp, struct tcphdr *th);
450 static void rack_remxt_tmr(struct tcpcb *tp);
451 static int
452 rack_set_sockopt(struct socket *so, struct sockopt *sopt,
453     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack);
454 static void rack_set_state(struct tcpcb *tp, struct tcp_rack *rack);
455 static int32_t rack_stopall(struct tcpcb *tp);
456 static void
457 rack_timer_activate(struct tcpcb *tp, uint32_t timer_type,
458     uint32_t delta);
459 static int32_t rack_timer_active(struct tcpcb *tp, uint32_t timer_type);
460 static void rack_timer_cancel(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int line);
461 static void rack_timer_stop(struct tcpcb *tp, uint32_t timer_type);
462 static uint32_t
463 rack_update_entry(struct tcpcb *tp, struct tcp_rack *rack,
464     struct rack_sendmap *rsm, uint32_t ts, int32_t * lenp);
465 static void
466 rack_update_rsm(struct tcpcb *tp, struct tcp_rack *rack,
467     struct rack_sendmap *rsm, uint32_t ts);
468 static int
469 rack_update_rtt(struct tcpcb *tp, struct tcp_rack *rack,
470     struct rack_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type, tcp_seq th_ack);
471 static int32_t tcp_addrack(module_t mod, int32_t type, void *data);
472 static int
473 rack_do_close_wait(struct mbuf *m, struct tcphdr *th,
474     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
475     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
476 static int
477 rack_do_closing(struct mbuf *m, struct tcphdr *th,
478     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
479     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
480 static int
481 rack_do_established(struct mbuf *m, struct tcphdr *th,
482     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
483     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
484 static int
485 rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th,
486     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
487     int32_t tlen, uint32_t tiwin, int32_t nxt_pkt, uint8_t iptos);
488 static int
489 rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th,
490     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
491     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
492 static int
493 rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th,
494     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
495     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
496 static int
497 rack_do_lastack(struct mbuf *m, struct tcphdr *th,
498     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
499     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
500 static int
501 rack_do_syn_recv(struct mbuf *m, struct tcphdr *th,
502     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
503     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
504 static int
505 rack_do_syn_sent(struct mbuf *m, struct tcphdr *th,
506     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
507     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
508 struct rack_sendmap *
509 tcp_rack_output(struct tcpcb *tp, struct tcp_rack *rack,
510     uint32_t tsused);
511 static void tcp_rack_xmit_timer(struct tcp_rack *rack, int32_t rtt,
512     uint32_t len, uint32_t us_tim, int confidence, struct rack_sendmap *rsm, uint16_t rtrcnt);
513 static void
514      tcp_rack_partialack(struct tcpcb *tp, struct tcphdr *th);
515 
516 int32_t rack_clear_counter=0;
517 
518 
519 static int
520 sysctl_rack_clear(SYSCTL_HANDLER_ARGS)
521 {
522 	uint32_t stat;
523 	int32_t error;
524 
525 	error = SYSCTL_OUT(req, &rack_clear_counter, sizeof(uint32_t));
526 	if (error || req->newptr == NULL)
527 		return error;
528 
529 	error = SYSCTL_IN(req, &stat, sizeof(uint32_t));
530 	if (error)
531 		return (error);
532 	if (stat == 1) {
533 #ifdef INVARIANTS
534 		printf("Clearing RACK counters\n");
535 #endif
536 		counter_u64_zero(rack_badfr);
537 		counter_u64_zero(rack_badfr_bytes);
538 		counter_u64_zero(rack_rtm_prr_retran);
539 		counter_u64_zero(rack_rtm_prr_newdata);
540 		counter_u64_zero(rack_timestamp_mismatch);
541 		counter_u64_zero(rack_reorder_seen);
542 		counter_u64_zero(rack_tlp_tot);
543 		counter_u64_zero(rack_tlp_newdata);
544 		counter_u64_zero(rack_tlp_retran);
545 		counter_u64_zero(rack_tlp_retran_bytes);
546 		counter_u64_zero(rack_tlp_retran_fail);
547 		counter_u64_zero(rack_to_tot);
548 		counter_u64_zero(rack_to_arm_rack);
549 		counter_u64_zero(rack_to_arm_tlp);
550 		counter_u64_zero(rack_paced_segments);
551 		counter_u64_zero(rack_calc_zero);
552 		counter_u64_zero(rack_calc_nonzero);
553 		counter_u64_zero(rack_unpaced_segments);
554 		counter_u64_zero(rack_saw_enobuf);
555 		counter_u64_zero(rack_saw_enetunreach);
556 		counter_u64_zero(rack_per_timer_hole);
557 		counter_u64_zero(rack_to_alloc_hard);
558 		counter_u64_zero(rack_to_alloc_emerg);
559 		counter_u64_zero(rack_sack_proc_all);
560 		counter_u64_zero(rack_sack_proc_short);
561 		counter_u64_zero(rack_sack_proc_restart);
562 		counter_u64_zero(rack_to_alloc);
563 		counter_u64_zero(rack_to_alloc_limited);
564 		counter_u64_zero(rack_alloc_limited_conns);
565 		counter_u64_zero(rack_split_limited);
566 		counter_u64_zero(rack_find_high);
567 		counter_u64_zero(rack_tls_rwnd);
568 		counter_u64_zero(rack_tls_cwnd);
569 		counter_u64_zero(rack_tls_app);
570 		counter_u64_zero(rack_tls_other);
571 		counter_u64_zero(rack_tls_filled);
572 		counter_u64_zero(rack_tls_rxt);
573 		counter_u64_zero(rack_tls_tlp);
574 		counter_u64_zero(rack_sack_attacks_detected);
575 		counter_u64_zero(rack_sack_attacks_reversed);
576 		counter_u64_zero(rack_sack_used_next_merge);
577 		counter_u64_zero(rack_sack_used_prev_merge);
578 		counter_u64_zero(rack_sack_splits);
579 		counter_u64_zero(rack_sack_skipped_acked);
580 		counter_u64_zero(rack_ack_total);
581 		counter_u64_zero(rack_express_sack);
582 		counter_u64_zero(rack_sack_total);
583 		counter_u64_zero(rack_move_none);
584 		counter_u64_zero(rack_move_some);
585 		counter_u64_zero(rack_used_tlpmethod);
586 		counter_u64_zero(rack_used_tlpmethod2);
587 		counter_u64_zero(rack_enter_tlp_calc);
588 		counter_u64_zero(rack_progress_drops);
589 		counter_u64_zero(rack_tlp_does_nada);
590 		counter_u64_zero(rack_try_scwnd);
591 		counter_u64_zero(rack_collapsed_win);
592 
593 	}
594 	rack_clear_counter = 0;
595 	return (0);
596 }
597 
598 
599 
600 static void
601 rack_init_sysctls(void)
602 {
603 	struct sysctl_oid *rack_counters;
604 	struct sysctl_oid *rack_attack;
605 	struct sysctl_oid *rack_pacing;
606 	struct sysctl_oid *rack_timely;
607 	struct sysctl_oid *rack_timers;
608 	struct sysctl_oid *rack_tlp;
609 	struct sysctl_oid *rack_misc;
610 	struct sysctl_oid *rack_measure;
611 	struct sysctl_oid *rack_probertt;
612 
613 	rack_attack = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
614 	    SYSCTL_CHILDREN(rack_sysctl_root),
615 	    OID_AUTO,
616 	    "sack_attack",
617 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
618 	    "Rack Sack Attack Counters and Controls");
619 	rack_counters = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
620 	    SYSCTL_CHILDREN(rack_sysctl_root),
621 	    OID_AUTO,
622 	    "stats",
623 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
624 	    "Rack Counters");
625 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
626 	    SYSCTL_CHILDREN(rack_sysctl_root),
627 	    OID_AUTO, "rate_sample_method", CTLFLAG_RW,
628 	    &rack_rate_sample_method , USE_RTT_LOW,
629 	    "What method should we use for rate sampling 0=high, 1=low ");
630 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
631 	    SYSCTL_CHILDREN(rack_sysctl_root),
632 	    OID_AUTO, "hw_tlsmax", CTLFLAG_RW,
633 	    &rack_hw_tls_max_seg , 3,
634 	    "What is the maximum number of full TLS records that will be sent at once");
635 	/* Probe rtt related controls */
636 	rack_probertt = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
637 	    SYSCTL_CHILDREN(rack_sysctl_root),
638 	    OID_AUTO,
639 	    "probertt",
640 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
641 	    "ProbeRTT related Controls");
642 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
643 	    SYSCTL_CHILDREN(rack_probertt),
644 	    OID_AUTO, "exit_per_hpb", CTLFLAG_RW,
645 	    &rack_atexit_prtt_hbp, 130,
646 	    "What percentage above goodput do we clamp CA/SS to at exit on high-BDP path 110%");
647 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
648 	    SYSCTL_CHILDREN(rack_probertt),
649 	    OID_AUTO, "exit_per_nonhpb", CTLFLAG_RW,
650 	    &rack_atexit_prtt, 130,
651 	    "What percentage above goodput do we clamp CA/SS to at exit on a non high-BDP path 100%");
652 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
653 	    SYSCTL_CHILDREN(rack_probertt),
654 	    OID_AUTO, "gp_per_mul", CTLFLAG_RW,
655 	    &rack_per_of_gp_probertt, 60,
656 	    "What percentage of goodput do we pace at in probertt");
657 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
658 	    SYSCTL_CHILDREN(rack_probertt),
659 	    OID_AUTO, "gp_per_reduce", CTLFLAG_RW,
660 	    &rack_per_of_gp_probertt_reduce, 10,
661 	    "What percentage of goodput do we reduce every gp_srtt");
662 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
663 	    SYSCTL_CHILDREN(rack_probertt),
664 	    OID_AUTO, "gp_per_low", CTLFLAG_RW,
665 	    &rack_per_of_gp_lowthresh, 40,
666 	    "What percentage of goodput do we allow the multiplier to fall to");
667 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
668 	    SYSCTL_CHILDREN(rack_probertt),
669 	    OID_AUTO, "time_between", CTLFLAG_RW,
670 	    & rack_time_between_probertt, 96000000,
671 	    "How many useconds between the lowest rtt falling must past before we enter probertt");
672 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
673 	    SYSCTL_CHILDREN(rack_probertt),
674 	    OID_AUTO, "safety", CTLFLAG_RW,
675 	    &rack_probe_rtt_safety_val, 2000000,
676 	    "If not zero, provides a maximum usecond that you can stay in probertt (2sec = 2000000)");
677 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
678 	    SYSCTL_CHILDREN(rack_probertt),
679 	    OID_AUTO, "sets_cwnd", CTLFLAG_RW,
680 	    &rack_probe_rtt_sets_cwnd, 0,
681 	    "Do we set the cwnd too (if always_lower is on)");
682 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
683 	    SYSCTL_CHILDREN(rack_probertt),
684 	    OID_AUTO, "maxdrainsrtts", CTLFLAG_RW,
685 	    &rack_max_drain_wait, 2,
686 	    "Maximum number of gp_srtt's to hold in drain waiting for flight to reach goal");
687 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
688 	    SYSCTL_CHILDREN(rack_probertt),
689 	    OID_AUTO, "mustdrainsrtts", CTLFLAG_RW,
690 	    &rack_must_drain, 1,
691 	    "We must drain this many gp_srtt's waiting for flight to reach goal");
692 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
693 	    SYSCTL_CHILDREN(rack_probertt),
694 	    OID_AUTO, "goal_use_min_entry", CTLFLAG_RW,
695 	    &rack_probertt_use_min_rtt_entry, 1,
696 	    "Should we use the min-rtt to calculate the goal rtt (else gp_srtt) at entry");
697 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
698 	    SYSCTL_CHILDREN(rack_probertt),
699 	    OID_AUTO, "goal_use_min_exit", CTLFLAG_RW,
700 	    &rack_probertt_use_min_rtt_exit, 0,
701 	    "How to set cwnd at exit, 0 - dynamic, 1 - use min-rtt, 2 - use curgprtt, 3 - entry gp-rtt");
702 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
703 	    SYSCTL_CHILDREN(rack_probertt),
704 	    OID_AUTO, "length_div", CTLFLAG_RW,
705 	    &rack_probertt_gpsrtt_cnt_div, 0,
706 	    "How many recent goodput srtt periods plus hold tim does probertt last (bottom of fraction)");
707 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
708 	    SYSCTL_CHILDREN(rack_probertt),
709 	    OID_AUTO, "length_mul", CTLFLAG_RW,
710 	    &rack_probertt_gpsrtt_cnt_mul, 0,
711 	    "How many recent goodput srtt periods plus hold tim does probertt last (top of fraction)");
712 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
713 	    SYSCTL_CHILDREN(rack_probertt),
714 	    OID_AUTO, "holdtim_at_target", CTLFLAG_RW,
715 	    &rack_min_probertt_hold, 200000,
716 	    "What is the minimum time we hold probertt at target");
717 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
718 	    SYSCTL_CHILDREN(rack_probertt),
719 	    OID_AUTO, "filter_life", CTLFLAG_RW,
720 	    &rack_probertt_filter_life, 10000000,
721 	    "What is the time for the filters life in useconds");
722 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
723 	    SYSCTL_CHILDREN(rack_probertt),
724 	    OID_AUTO, "lower_within", CTLFLAG_RW,
725 	    &rack_probertt_lower_within, 10,
726 	    "If the rtt goes lower within this percentage of the time, go into probe-rtt");
727 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
728 	    SYSCTL_CHILDREN(rack_probertt),
729 	    OID_AUTO, "must_move", CTLFLAG_RW,
730 	    &rack_min_rtt_movement, 250,
731 	    "How much is the minimum movement in rtt to count as a drop for probertt purposes");
732 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
733 	    SYSCTL_CHILDREN(rack_probertt),
734 	    OID_AUTO, "clear_is_cnts", CTLFLAG_RW,
735 	    &rack_probertt_clear_is, 1,
736 	    "Do we clear I/S counts on exiting probe-rtt");
737 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
738 	    SYSCTL_CHILDREN(rack_probertt),
739 	    OID_AUTO, "hbp_extra_drain", CTLFLAG_RW,
740 	    &rack_max_drain_hbp, 1,
741 	    "How many extra drain gpsrtt's do we get in highly buffered paths");
742 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
743 	    SYSCTL_CHILDREN(rack_probertt),
744 	    OID_AUTO, "hbp_threshold", CTLFLAG_RW,
745 	    &rack_hbp_thresh, 3,
746 	    "We are highly buffered if min_rtt_seen / max_rtt_seen > this-threshold");
747 	/* Pacing related sysctls */
748 	rack_pacing = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
749 	    SYSCTL_CHILDREN(rack_sysctl_root),
750 	    OID_AUTO,
751 	    "pacing",
752 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
753 	    "Pacing related Controls");
754 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
755 	    SYSCTL_CHILDREN(rack_pacing),
756 	    OID_AUTO, "max_pace_over", CTLFLAG_RW,
757 	    &rack_max_per_above, 30,
758 	    "What is the maximum allowable percentage that we can pace above (so 30 = 130% of our goal)");
759 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
760 	    SYSCTL_CHILDREN(rack_pacing),
761 	    OID_AUTO, "pace_to_one", CTLFLAG_RW,
762 	    &rack_pace_one_seg, 0,
763 	    "Do we allow low b/w pacing of 1MSS instead of two");
764 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
765 	    SYSCTL_CHILDREN(rack_pacing),
766 	    OID_AUTO, "limit_wsrtt", CTLFLAG_RW,
767 	    &rack_limit_time_with_srtt, 0,
768 	    "Do we limit pacing time based on srtt");
769 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
770 	    SYSCTL_CHILDREN(rack_pacing),
771 	    OID_AUTO, "init_win", CTLFLAG_RW,
772 	    &rack_default_init_window, 0,
773 	    "Do we have a rack initial window 0 = system default");
774 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
775 	    SYSCTL_CHILDREN(rack_pacing),
776 	    OID_AUTO, "hw_pacing_adjust", CTLFLAG_RW,
777 	    &rack_hw_pace_adjust, 0,
778 	    "What percentage do we raise the MSS by (11 = 1.1%)");
779 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
780 	    SYSCTL_CHILDREN(rack_pacing),
781 	    OID_AUTO, "gp_per_ss", CTLFLAG_RW,
782 	    &rack_per_of_gp_ss, 250,
783 	    "If non zero, what percentage of goodput to pace at in slow start");
784 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
785 	    SYSCTL_CHILDREN(rack_pacing),
786 	    OID_AUTO, "gp_per_ca", CTLFLAG_RW,
787 	    &rack_per_of_gp_ca, 150,
788 	    "If non zero, what percentage of goodput to pace at in congestion avoidance");
789 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
790 	    SYSCTL_CHILDREN(rack_pacing),
791 	    OID_AUTO, "gp_per_rec", CTLFLAG_RW,
792 	    &rack_per_of_gp_rec, 200,
793 	    "If non zero, what percentage of goodput to pace at in recovery");
794 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
795 	    SYSCTL_CHILDREN(rack_pacing),
796 	    OID_AUTO, "pace_max_seg", CTLFLAG_RW,
797 	    &rack_hptsi_segments, 40,
798 	    "What size is the max for TSO segments in pacing and burst mitigation");
799 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
800 	    SYSCTL_CHILDREN(rack_pacing),
801 	    OID_AUTO, "burst_reduces", CTLFLAG_RW,
802 	    &rack_slot_reduction, 4,
803 	    "When doing only burst mitigation what is the reduce divisor");
804 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
805 	    SYSCTL_CHILDREN(rack_sysctl_root),
806 	    OID_AUTO, "use_pacing", CTLFLAG_RW,
807 	    &rack_pace_every_seg, 0,
808 	    "If set we use pacing, if clear we use only the original burst mitigation");
809 
810 	rack_timely = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
811 	    SYSCTL_CHILDREN(rack_sysctl_root),
812 	    OID_AUTO,
813 	    "timely",
814 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
815 	    "Rack Timely RTT Controls");
816 	/* Timely based GP dynmics */
817 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
818 	    SYSCTL_CHILDREN(rack_timely),
819 	    OID_AUTO, "upper", CTLFLAG_RW,
820 	    &rack_gp_per_bw_mul_up, 2,
821 	    "Rack timely upper range for equal b/w (in percentage)");
822 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
823 	    SYSCTL_CHILDREN(rack_timely),
824 	    OID_AUTO, "lower", CTLFLAG_RW,
825 	    &rack_gp_per_bw_mul_down, 4,
826 	    "Rack timely lower range for equal b/w (in percentage)");
827 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
828 	    SYSCTL_CHILDREN(rack_timely),
829 	    OID_AUTO, "rtt_max_mul", CTLFLAG_RW,
830 	    &rack_gp_rtt_maxmul, 3,
831 	    "Rack timely multipler of lowest rtt for rtt_max");
832 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
833 	    SYSCTL_CHILDREN(rack_timely),
834 	    OID_AUTO, "rtt_min_div", CTLFLAG_RW,
835 	    &rack_gp_rtt_mindiv, 4,
836 	    "Rack timely divisor used for rtt + (rtt * mul/divisor) for check for lower rtt");
837 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
838 	    SYSCTL_CHILDREN(rack_timely),
839 	    OID_AUTO, "rtt_min_mul", CTLFLAG_RW,
840 	    &rack_gp_rtt_minmul, 1,
841 	    "Rack timely multiplier used for rtt + (rtt * mul/divisor) for check for lower rtt");
842 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
843 	    SYSCTL_CHILDREN(rack_timely),
844 	    OID_AUTO, "decrease", CTLFLAG_RW,
845 	    &rack_gp_decrease_per, 20,
846 	    "Rack timely decrease percentage of our GP multiplication factor");
847 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
848 	    SYSCTL_CHILDREN(rack_timely),
849 	    OID_AUTO, "increase", CTLFLAG_RW,
850 	    &rack_gp_increase_per, 2,
851 	    "Rack timely increase perentage of our GP multiplication factor");
852 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
853 	    SYSCTL_CHILDREN(rack_timely),
854 	    OID_AUTO, "lowerbound", CTLFLAG_RW,
855 	    &rack_per_lower_bound, 50,
856 	    "Rack timely lowest percentage we allow GP multiplier to fall to");
857 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
858 	    SYSCTL_CHILDREN(rack_timely),
859 	    OID_AUTO, "upperboundss", CTLFLAG_RW,
860 	    &rack_per_upper_bound_ss, 0,
861 	    "Rack timely higest percentage we allow GP multiplier in SS to raise to (0 is no upperbound)");
862 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
863 	    SYSCTL_CHILDREN(rack_timely),
864 	    OID_AUTO, "upperboundca", CTLFLAG_RW,
865 	    &rack_per_upper_bound_ca, 0,
866 	    "Rack timely higest percentage we allow GP multiplier to CA raise to (0 is no upperbound)");
867 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
868 	    SYSCTL_CHILDREN(rack_timely),
869 	    OID_AUTO, "dynamicgp", CTLFLAG_RW,
870 	    &rack_do_dyn_mul, 0,
871 	    "Rack timely do we enable dynmaic timely goodput by default");
872 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
873 	    SYSCTL_CHILDREN(rack_timely),
874 	    OID_AUTO, "no_rec_red", CTLFLAG_RW,
875 	    &rack_gp_no_rec_chg, 1,
876 	    "Rack timely do we prohibit the recovery multiplier from being lowered");
877 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
878 	    SYSCTL_CHILDREN(rack_timely),
879 	    OID_AUTO, "red_clear_cnt", CTLFLAG_RW,
880 	    &rack_timely_dec_clear, 6,
881 	    "Rack timely what threshold do we count to before another boost during b/w decent");
882 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
883 	    SYSCTL_CHILDREN(rack_timely),
884 	    OID_AUTO, "max_push_rise", CTLFLAG_RW,
885 	    &rack_timely_max_push_rise, 3,
886 	    "Rack timely how many times do we push up with b/w increase");
887 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
888 	    SYSCTL_CHILDREN(rack_timely),
889 	    OID_AUTO, "max_push_drop", CTLFLAG_RW,
890 	    &rack_timely_max_push_drop, 3,
891 	    "Rack timely how many times do we push back on b/w decent");
892 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
893 	    SYSCTL_CHILDREN(rack_timely),
894 	    OID_AUTO, "min_segs", CTLFLAG_RW,
895 	    &rack_timely_min_segs, 4,
896 	    "Rack timely when setting the cwnd what is the min num segments");
897 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
898 	    SYSCTL_CHILDREN(rack_timely),
899 	    OID_AUTO, "noback_max", CTLFLAG_RW,
900 	    &rack_use_max_for_nobackoff, 0,
901 	    "Rack timely when deciding if to backoff on a loss, do we use under max rtt else min");
902 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
903 	    SYSCTL_CHILDREN(rack_timely),
904 	    OID_AUTO, "interim_timely_only", CTLFLAG_RW,
905 	    &rack_timely_int_timely_only, 0,
906 	    "Rack timely when doing interim timely's do we only do timely (no b/w consideration)");
907 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
908 	    SYSCTL_CHILDREN(rack_timely),
909 	    OID_AUTO, "nonstop", CTLFLAG_RW,
910 	    &rack_timely_no_stopping, 0,
911 	    "Rack timely don't stop increase");
912 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
913 	    SYSCTL_CHILDREN(rack_timely),
914 	    OID_AUTO, "dec_raise_thresh", CTLFLAG_RW,
915 	    &rack_down_raise_thresh, 100,
916 	    "If the CA or SS is below this threshold raise on the first 3 b/w lowers (0=always)");
917 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
918 	    SYSCTL_CHILDREN(rack_timely),
919 	    OID_AUTO, "bottom_drag_segs", CTLFLAG_RW,
920 	    &rack_req_segs, 1,
921 	    "Bottom dragging if not these many segments outstanding and room");
922 
923 	/* TLP and Rack related parameters */
924 	rack_tlp = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
925 	    SYSCTL_CHILDREN(rack_sysctl_root),
926 	    OID_AUTO,
927 	    "tlp",
928 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
929 	    "TLP and Rack related Controls");
930 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
931 	    SYSCTL_CHILDREN(rack_tlp),
932 	    OID_AUTO, "use_rrr", CTLFLAG_RW,
933 	    &use_rack_rr, 1,
934 	    "Do we use Rack Rapid Recovery");
935 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
936 	    SYSCTL_CHILDREN(rack_tlp),
937 	    OID_AUTO, "nonrxt_use_cr", CTLFLAG_RW,
938 	    &rack_non_rxt_use_cr, 0,
939 	    "Do we use ss/ca rate if in recovery we are transmitting a new data chunk");
940 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
941 	    SYSCTL_CHILDREN(rack_tlp),
942 	    OID_AUTO, "tlpmethod", CTLFLAG_RW,
943 	    &rack_tlp_threshold_use, TLP_USE_TWO_ONE,
944 	    "What method do we do for TLP time calc 0=no-de-ack-comp, 1=ID, 2=2.1, 3=2.2");
945 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
946 	    SYSCTL_CHILDREN(rack_tlp),
947 	    OID_AUTO, "limit", CTLFLAG_RW,
948 	    &rack_tlp_limit, 2,
949 	    "How many TLP's can be sent without sending new data");
950 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
951 	    SYSCTL_CHILDREN(rack_tlp),
952 	    OID_AUTO, "use_greater", CTLFLAG_RW,
953 	    &rack_tlp_use_greater, 1,
954 	    "Should we use the rack_rtt time if its greater than srtt");
955 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
956 	    SYSCTL_CHILDREN(rack_tlp),
957 	    OID_AUTO, "tlpminto", CTLFLAG_RW,
958 	    &rack_tlp_min, 10,
959 	    "TLP minimum timeout per the specification (10ms)");
960 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
961 	    SYSCTL_CHILDREN(rack_tlp),
962 	    OID_AUTO, "send_oldest", CTLFLAG_RW,
963 	    &rack_always_send_oldest, 0,
964 	    "Should we always send the oldest TLP and RACK-TLP");
965 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
966 	    SYSCTL_CHILDREN(rack_tlp),
967 	    OID_AUTO, "rack_tlimit", CTLFLAG_RW,
968 	    &rack_limited_retran, 0,
969 	    "How many times can a rack timeout drive out sends");
970 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
971 	    SYSCTL_CHILDREN(rack_tlp),
972 	    OID_AUTO, "tlp_retry", CTLFLAG_RW,
973 	    &rack_tlp_max_resend, 2,
974 	    "How many times does TLP retry a single segment or multiple with no ACK");
975 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
976 	    SYSCTL_CHILDREN(rack_tlp),
977 	    OID_AUTO, "tlp_cwnd_flag", CTLFLAG_RW,
978 	    &rack_lower_cwnd_at_tlp, 0,
979 	    "When a TLP completes a retran should we enter recovery");
980 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
981 	    SYSCTL_CHILDREN(rack_tlp),
982 	    OID_AUTO, "reorder_thresh", CTLFLAG_RW,
983 	    &rack_reorder_thresh, 2,
984 	    "What factor for rack will be added when seeing reordering (shift right)");
985 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
986 	    SYSCTL_CHILDREN(rack_tlp),
987 	    OID_AUTO, "rtt_tlp_thresh", CTLFLAG_RW,
988 	    &rack_tlp_thresh, 1,
989 	    "What divisor for TLP rtt/retran will be added (1=rtt, 2=1/2 rtt etc)");
990 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
991 	    SYSCTL_CHILDREN(rack_tlp),
992 	    OID_AUTO, "reorder_fade", CTLFLAG_RW,
993 	    &rack_reorder_fade, 0,
994 	    "Does reorder detection fade, if so how many ms (0 means never)");
995 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
996 	    SYSCTL_CHILDREN(rack_tlp),
997 	    OID_AUTO, "pktdelay", CTLFLAG_RW,
998 	    &rack_pkt_delay, 1,
999 	    "Extra RACK time (in ms) besides reordering thresh");
1000 
1001 	/* Timer related controls */
1002 	rack_timers = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1003 	    SYSCTL_CHILDREN(rack_sysctl_root),
1004 	    OID_AUTO,
1005 	    "timers",
1006 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1007 	    "Timer related controls");
1008 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1009 	    SYSCTL_CHILDREN(rack_timers),
1010 	    OID_AUTO, "persmin", CTLFLAG_RW,
1011 	    &rack_persist_min, 250,
1012 	    "What is the minimum time in milliseconds between persists");
1013 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1014 	    SYSCTL_CHILDREN(rack_timers),
1015 	    OID_AUTO, "persmax", CTLFLAG_RW,
1016 	    &rack_persist_max, 2000,
1017 	    "What is the largest delay in milliseconds between persists");
1018 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1019 	    SYSCTL_CHILDREN(rack_timers),
1020 	    OID_AUTO, "delayed_ack", CTLFLAG_RW,
1021 	    &rack_delayed_ack_time, 200,
1022 	    "Delayed ack time (200ms)");
1023 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1024 	    SYSCTL_CHILDREN(rack_timers),
1025 	    OID_AUTO, "minrto", CTLFLAG_RW,
1026 	    &rack_rto_min, 0,
1027 	    "Minimum RTO in ms -- set with caution below 1000 due to TLP");
1028 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1029 	    SYSCTL_CHILDREN(rack_timers),
1030 	    OID_AUTO, "maxrto", CTLFLAG_RW,
1031 	    &rack_rto_max, 0,
1032 	    "Maxiumum RTO in ms -- should be at least as large as min_rto");
1033 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1034 	    SYSCTL_CHILDREN(rack_timers),
1035 	    OID_AUTO, "minto", CTLFLAG_RW,
1036 	    &rack_min_to, 1,
1037 	    "Minimum rack timeout in milliseconds");
1038 	/* Measure controls */
1039 	rack_measure = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1040 	    SYSCTL_CHILDREN(rack_sysctl_root),
1041 	    OID_AUTO,
1042 	    "measure",
1043 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1044 	    "Measure related controls");
1045 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1046 	    SYSCTL_CHILDREN(rack_measure),
1047 	    OID_AUTO, "wma_divisor", CTLFLAG_RW,
1048 	    &rack_wma_divisor, 8,
1049 	    "When doing b/w calculation what is the  divisor for the WMA");
1050 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1051 	    SYSCTL_CHILDREN(rack_measure),
1052 	    OID_AUTO, "end_cwnd", CTLFLAG_RW,
1053 	    &rack_cwnd_block_ends_measure, 0,
1054 	    "Does a cwnd just-return end the measurement window (app limited)");
1055 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1056 	    SYSCTL_CHILDREN(rack_measure),
1057 	    OID_AUTO, "end_rwnd", CTLFLAG_RW,
1058 	    &rack_rwnd_block_ends_measure, 0,
1059 	    "Does an rwnd just-return end the measurement window (app limited -- not persists)");
1060 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1061 	    SYSCTL_CHILDREN(rack_measure),
1062 	    OID_AUTO, "min_target", CTLFLAG_RW,
1063 	    &rack_def_data_window, 20,
1064 	    "What is the minimum target window (in mss) for a GP measurements");
1065 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1066 	    SYSCTL_CHILDREN(rack_measure),
1067 	    OID_AUTO, "goal_bdp", CTLFLAG_RW,
1068 	    &rack_goal_bdp, 2,
1069 	    "What is the goal BDP to measure");
1070 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1071 	    SYSCTL_CHILDREN(rack_measure),
1072 	    OID_AUTO, "min_srtts", CTLFLAG_RW,
1073 	    &rack_min_srtts, 1,
1074 	    "What is the goal BDP to measure");
1075 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1076 	    SYSCTL_CHILDREN(rack_measure),
1077 	    OID_AUTO, "min_measure_tim", CTLFLAG_RW,
1078 	    &rack_min_measure_usec, 0,
1079 	    "What is the Minimum time time for a measurement if 0, this is off");
1080 	/* Misc rack controls */
1081 	rack_misc = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1082 	    SYSCTL_CHILDREN(rack_sysctl_root),
1083 	    OID_AUTO,
1084 	    "misc",
1085 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1086 	    "Misc related controls");
1087 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1088 	    SYSCTL_CHILDREN(rack_misc),
1089 	    OID_AUTO, "shared_cwnd", CTLFLAG_RW,
1090 	    &rack_enable_shared_cwnd, 0,
1091 	    "Should RACK try to use the shared cwnd on connections where allowed");
1092 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1093 	    SYSCTL_CHILDREN(rack_misc),
1094 	    OID_AUTO, "limits_on_scwnd", CTLFLAG_RW,
1095 	    &rack_limits_scwnd, 1,
1096 	    "Should RACK place low end time limits on the shared cwnd feature");
1097 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1098 	    SYSCTL_CHILDREN(rack_misc),
1099 	    OID_AUTO, "non_paced_lro_queue", CTLFLAG_RW,
1100 	    &rack_enable_mqueue_for_nonpaced, 0,
1101 	    "Should RACK use mbuf queuing for non-paced connections");
1102 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1103 	    SYSCTL_CHILDREN(rack_misc),
1104 	    OID_AUTO, "iMac_dack", CTLFLAG_RW,
1105 	    &rack_use_imac_dack, 0,
1106 	    "Should RACK try to emulate iMac delayed ack");
1107 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1108 	    SYSCTL_CHILDREN(rack_misc),
1109 	    OID_AUTO, "no_prr", CTLFLAG_RW,
1110 	    &rack_disable_prr, 0,
1111 	    "Should RACK not use prr and only pace (must have pacing on)");
1112 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1113 	    SYSCTL_CHILDREN(rack_misc),
1114 	    OID_AUTO, "bb_verbose", CTLFLAG_RW,
1115 	    &rack_verbose_logging, 0,
1116 	    "Should RACK black box logging be verbose");
1117 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1118 	    SYSCTL_CHILDREN(rack_misc),
1119 	    OID_AUTO, "data_after_close", CTLFLAG_RW,
1120 	    &rack_ignore_data_after_close, 1,
1121 	    "Do we hold off sending a RST until all pending data is ack'd");
1122 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1123 	    SYSCTL_CHILDREN(rack_misc),
1124 	    OID_AUTO, "no_sack_needed", CTLFLAG_RW,
1125 	    &rack_sack_not_required, 0,
1126 	    "Do we allow rack to run on connections not supporting SACK");
1127 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1128 	    SYSCTL_CHILDREN(rack_misc),
1129 	    OID_AUTO, "recovery_loss_prop", CTLFLAG_RW,
1130 	    &rack_use_proportional_reduce, 0,
1131 	    "Should we proportionaly reduce cwnd based on the number of losses ");
1132 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1133 	    SYSCTL_CHILDREN(rack_misc),
1134 	    OID_AUTO, "recovery_prop", CTLFLAG_RW,
1135 	    &rack_proportional_rate, 10,
1136 	    "What percent reduction per loss");
1137 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1138 	    SYSCTL_CHILDREN(rack_misc),
1139 	    OID_AUTO, "prr_sendalot", CTLFLAG_RW,
1140 	    &rack_send_a_lot_in_prr, 1,
1141 	    "Send a lot in prr");
1142 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1143 	    SYSCTL_CHILDREN(rack_misc),
1144 	    OID_AUTO, "earlyrecovery", CTLFLAG_RW,
1145 	    &rack_early_recovery, 1,
1146 	    "Do we do early recovery with rack");
1147 	/* Sack Attacker detection stuff */
1148 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1149 	    SYSCTL_CHILDREN(rack_attack),
1150 	    OID_AUTO, "detect_highsackratio", CTLFLAG_RW,
1151 	    &rack_highest_sack_thresh_seen, 0,
1152 	    "Highest sack to ack ratio seen");
1153 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1154 	    SYSCTL_CHILDREN(rack_attack),
1155 	    OID_AUTO, "detect_highmoveratio", CTLFLAG_RW,
1156 	    &rack_highest_move_thresh_seen, 0,
1157 	    "Highest move to non-move ratio seen");
1158 	rack_ack_total = counter_u64_alloc(M_WAITOK);
1159 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1160 	    SYSCTL_CHILDREN(rack_attack),
1161 	    OID_AUTO, "acktotal", CTLFLAG_RD,
1162 	    &rack_ack_total,
1163 	    "Total number of Ack's");
1164 	rack_express_sack = counter_u64_alloc(M_WAITOK);
1165 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1166 	    SYSCTL_CHILDREN(rack_attack),
1167 	    OID_AUTO, "exp_sacktotal", CTLFLAG_RD,
1168 	    &rack_express_sack,
1169 	    "Total expresss number of Sack's");
1170 	rack_sack_total = counter_u64_alloc(M_WAITOK);
1171 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1172 	    SYSCTL_CHILDREN(rack_attack),
1173 	    OID_AUTO, "sacktotal", CTLFLAG_RD,
1174 	    &rack_sack_total,
1175 	    "Total number of SACKs");
1176 	rack_move_none = counter_u64_alloc(M_WAITOK);
1177 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1178 	    SYSCTL_CHILDREN(rack_attack),
1179 	    OID_AUTO, "move_none", CTLFLAG_RD,
1180 	    &rack_move_none,
1181 	    "Total number of SACK index reuse of postions under threshold");
1182 	rack_move_some = counter_u64_alloc(M_WAITOK);
1183 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1184 	    SYSCTL_CHILDREN(rack_attack),
1185 	    OID_AUTO, "move_some", CTLFLAG_RD,
1186 	    &rack_move_some,
1187 	    "Total number of SACK index reuse of postions over threshold");
1188 	rack_sack_attacks_detected = counter_u64_alloc(M_WAITOK);
1189 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1190 	    SYSCTL_CHILDREN(rack_attack),
1191 	    OID_AUTO, "attacks", CTLFLAG_RD,
1192 	    &rack_sack_attacks_detected,
1193 	    "Total number of SACK attackers that had sack disabled");
1194 	rack_sack_attacks_reversed = counter_u64_alloc(M_WAITOK);
1195 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1196 	    SYSCTL_CHILDREN(rack_attack),
1197 	    OID_AUTO, "reversed", CTLFLAG_RD,
1198 	    &rack_sack_attacks_reversed,
1199 	    "Total number of SACK attackers that were later determined false positive");
1200 	rack_sack_used_next_merge = counter_u64_alloc(M_WAITOK);
1201 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1202 	    SYSCTL_CHILDREN(rack_attack),
1203 	    OID_AUTO, "nextmerge", CTLFLAG_RD,
1204 	    &rack_sack_used_next_merge,
1205 	    "Total number of times we used the next merge");
1206 	rack_sack_used_prev_merge = counter_u64_alloc(M_WAITOK);
1207 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1208 	    SYSCTL_CHILDREN(rack_attack),
1209 	    OID_AUTO, "prevmerge", CTLFLAG_RD,
1210 	    &rack_sack_used_prev_merge,
1211 	    "Total number of times we used the prev merge");
1212 	/* Counters */
1213 	rack_badfr = counter_u64_alloc(M_WAITOK);
1214 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1215 	    SYSCTL_CHILDREN(rack_counters),
1216 	    OID_AUTO, "badfr", CTLFLAG_RD,
1217 	    &rack_badfr, "Total number of bad FRs");
1218 	rack_badfr_bytes = counter_u64_alloc(M_WAITOK);
1219 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1220 	    SYSCTL_CHILDREN(rack_counters),
1221 	    OID_AUTO, "badfr_bytes", CTLFLAG_RD,
1222 	    &rack_badfr_bytes, "Total number of bad FRs");
1223 	rack_rtm_prr_retran = counter_u64_alloc(M_WAITOK);
1224 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1225 	    SYSCTL_CHILDREN(rack_counters),
1226 	    OID_AUTO, "prrsndret", CTLFLAG_RD,
1227 	    &rack_rtm_prr_retran,
1228 	    "Total number of prr based retransmits");
1229 	rack_rtm_prr_newdata = counter_u64_alloc(M_WAITOK);
1230 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1231 	    SYSCTL_CHILDREN(rack_counters),
1232 	    OID_AUTO, "prrsndnew", CTLFLAG_RD,
1233 	    &rack_rtm_prr_newdata,
1234 	    "Total number of prr based new transmits");
1235 	rack_timestamp_mismatch = counter_u64_alloc(M_WAITOK);
1236 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1237 	    SYSCTL_CHILDREN(rack_counters),
1238 	    OID_AUTO, "tsnf", CTLFLAG_RD,
1239 	    &rack_timestamp_mismatch,
1240 	    "Total number of timestamps that we could not find the reported ts");
1241 	rack_find_high = counter_u64_alloc(M_WAITOK);
1242 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1243 	    SYSCTL_CHILDREN(rack_counters),
1244 	    OID_AUTO, "findhigh", CTLFLAG_RD,
1245 	    &rack_find_high,
1246 	    "Total number of FIN causing find-high");
1247 	rack_reorder_seen = counter_u64_alloc(M_WAITOK);
1248 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1249 	    SYSCTL_CHILDREN(rack_counters),
1250 	    OID_AUTO, "reordering", CTLFLAG_RD,
1251 	    &rack_reorder_seen,
1252 	    "Total number of times we added delay due to reordering");
1253 	rack_tlp_tot = counter_u64_alloc(M_WAITOK);
1254 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1255 	    SYSCTL_CHILDREN(rack_counters),
1256 	    OID_AUTO, "tlp_to_total", CTLFLAG_RD,
1257 	    &rack_tlp_tot,
1258 	    "Total number of tail loss probe expirations");
1259 	rack_tlp_newdata = counter_u64_alloc(M_WAITOK);
1260 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1261 	    SYSCTL_CHILDREN(rack_counters),
1262 	    OID_AUTO, "tlp_new", CTLFLAG_RD,
1263 	    &rack_tlp_newdata,
1264 	    "Total number of tail loss probe sending new data");
1265 	rack_tlp_retran = counter_u64_alloc(M_WAITOK);
1266 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1267 	    SYSCTL_CHILDREN(rack_counters),
1268 	    OID_AUTO, "tlp_retran", CTLFLAG_RD,
1269 	    &rack_tlp_retran,
1270 	    "Total number of tail loss probe sending retransmitted data");
1271 	rack_tlp_retran_bytes = counter_u64_alloc(M_WAITOK);
1272 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1273 	    SYSCTL_CHILDREN(rack_counters),
1274 	    OID_AUTO, "tlp_retran_bytes", CTLFLAG_RD,
1275 	    &rack_tlp_retran_bytes,
1276 	    "Total bytes of tail loss probe sending retransmitted data");
1277 	rack_tlp_retran_fail = counter_u64_alloc(M_WAITOK);
1278 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1279 	    SYSCTL_CHILDREN(rack_counters),
1280 	    OID_AUTO, "tlp_retran_fail", CTLFLAG_RD,
1281 	    &rack_tlp_retran_fail,
1282 	    "Total number of tail loss probe sending retransmitted data that failed (wait for t3)");
1283 	rack_to_tot = counter_u64_alloc(M_WAITOK);
1284 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1285 	    SYSCTL_CHILDREN(rack_counters),
1286 	    OID_AUTO, "rack_to_tot", CTLFLAG_RD,
1287 	    &rack_to_tot,
1288 	    "Total number of times the rack to expired");
1289 	rack_to_arm_rack = counter_u64_alloc(M_WAITOK);
1290 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1291 	    SYSCTL_CHILDREN(rack_counters),
1292 	    OID_AUTO, "arm_rack", CTLFLAG_RD,
1293 	    &rack_to_arm_rack,
1294 	    "Total number of times the rack timer armed");
1295 	rack_to_arm_tlp = counter_u64_alloc(M_WAITOK);
1296 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1297 	    SYSCTL_CHILDREN(rack_counters),
1298 	    OID_AUTO, "arm_tlp", CTLFLAG_RD,
1299 	    &rack_to_arm_tlp,
1300 	    "Total number of times the tlp timer armed");
1301 	rack_calc_zero = counter_u64_alloc(M_WAITOK);
1302 	rack_calc_nonzero = counter_u64_alloc(M_WAITOK);
1303 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1304 	    SYSCTL_CHILDREN(rack_counters),
1305 	    OID_AUTO, "calc_zero", CTLFLAG_RD,
1306 	    &rack_calc_zero,
1307 	    "Total number of times pacing time worked out to zero");
1308 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1309 	    SYSCTL_CHILDREN(rack_counters),
1310 	    OID_AUTO, "calc_nonzero", CTLFLAG_RD,
1311 	    &rack_calc_nonzero,
1312 	    "Total number of times pacing time worked out to non-zero");
1313 	rack_paced_segments = counter_u64_alloc(M_WAITOK);
1314 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1315 	    SYSCTL_CHILDREN(rack_counters),
1316 	    OID_AUTO, "paced", CTLFLAG_RD,
1317 	    &rack_paced_segments,
1318 	    "Total number of times a segment send caused hptsi");
1319 	rack_unpaced_segments = counter_u64_alloc(M_WAITOK);
1320 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1321 	    SYSCTL_CHILDREN(rack_counters),
1322 	    OID_AUTO, "unpaced", CTLFLAG_RD,
1323 	    &rack_unpaced_segments,
1324 	    "Total number of times a segment did not cause hptsi");
1325 	rack_saw_enobuf = counter_u64_alloc(M_WAITOK);
1326 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1327 	    SYSCTL_CHILDREN(rack_counters),
1328 	    OID_AUTO, "saw_enobufs", CTLFLAG_RD,
1329 	    &rack_saw_enobuf,
1330 	    "Total number of times a segment did not cause hptsi");
1331 	rack_saw_enetunreach = counter_u64_alloc(M_WAITOK);
1332 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1333 	    SYSCTL_CHILDREN(rack_counters),
1334 	    OID_AUTO, "saw_enetunreach", CTLFLAG_RD,
1335 	    &rack_saw_enetunreach,
1336 	    "Total number of times a segment did not cause hptsi");
1337 	rack_to_alloc = counter_u64_alloc(M_WAITOK);
1338 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1339 	    SYSCTL_CHILDREN(rack_counters),
1340 	    OID_AUTO, "allocs", CTLFLAG_RD,
1341 	    &rack_to_alloc,
1342 	    "Total allocations of tracking structures");
1343 	rack_to_alloc_hard = counter_u64_alloc(M_WAITOK);
1344 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1345 	    SYSCTL_CHILDREN(rack_counters),
1346 	    OID_AUTO, "allochard", CTLFLAG_RD,
1347 	    &rack_to_alloc_hard,
1348 	    "Total allocations done with sleeping the hard way");
1349 	rack_to_alloc_emerg = counter_u64_alloc(M_WAITOK);
1350 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1351 	    SYSCTL_CHILDREN(rack_counters),
1352 	    OID_AUTO, "allocemerg", CTLFLAG_RD,
1353 	    &rack_to_alloc_emerg,
1354 	    "Total allocations done from emergency cache");
1355 	rack_to_alloc_limited = counter_u64_alloc(M_WAITOK);
1356 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1357 	    SYSCTL_CHILDREN(rack_counters),
1358 	    OID_AUTO, "alloc_limited", CTLFLAG_RD,
1359 	    &rack_to_alloc_limited,
1360 	    "Total allocations dropped due to limit");
1361 	rack_alloc_limited_conns = counter_u64_alloc(M_WAITOK);
1362 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1363 	    SYSCTL_CHILDREN(rack_counters),
1364 	    OID_AUTO, "alloc_limited_conns", CTLFLAG_RD,
1365 	    &rack_alloc_limited_conns,
1366 	    "Connections with allocations dropped due to limit");
1367 	rack_split_limited = counter_u64_alloc(M_WAITOK);
1368 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1369 	    SYSCTL_CHILDREN(rack_counters),
1370 	    OID_AUTO, "split_limited", CTLFLAG_RD,
1371 	    &rack_split_limited,
1372 	    "Split allocations dropped due to limit");
1373 	rack_sack_proc_all = counter_u64_alloc(M_WAITOK);
1374 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1375 	    SYSCTL_CHILDREN(rack_counters),
1376 	    OID_AUTO, "sack_long", CTLFLAG_RD,
1377 	    &rack_sack_proc_all,
1378 	    "Total times we had to walk whole list for sack processing");
1379 	rack_sack_proc_restart = counter_u64_alloc(M_WAITOK);
1380 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1381 	    SYSCTL_CHILDREN(rack_counters),
1382 	    OID_AUTO, "sack_restart", CTLFLAG_RD,
1383 	    &rack_sack_proc_restart,
1384 	    "Total times we had to walk whole list due to a restart");
1385 	rack_sack_proc_short = counter_u64_alloc(M_WAITOK);
1386 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1387 	    SYSCTL_CHILDREN(rack_counters),
1388 	    OID_AUTO, "sack_short", CTLFLAG_RD,
1389 	    &rack_sack_proc_short,
1390 	    "Total times we took shortcut for sack processing");
1391 	rack_enter_tlp_calc = counter_u64_alloc(M_WAITOK);
1392 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1393 	    SYSCTL_CHILDREN(rack_counters),
1394 	    OID_AUTO, "tlp_calc_entered", CTLFLAG_RD,
1395 	    &rack_enter_tlp_calc,
1396 	    "Total times we called calc-tlp");
1397 	rack_used_tlpmethod = counter_u64_alloc(M_WAITOK);
1398 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1399 	    SYSCTL_CHILDREN(rack_counters),
1400 	    OID_AUTO, "hit_tlp_method", CTLFLAG_RD,
1401 	    &rack_used_tlpmethod,
1402 	    "Total number of runt sacks");
1403 	rack_used_tlpmethod2 = counter_u64_alloc(M_WAITOK);
1404 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1405 	    SYSCTL_CHILDREN(rack_counters),
1406 	    OID_AUTO, "hit_tlp_method2", CTLFLAG_RD,
1407 	    &rack_used_tlpmethod2,
1408 	    "Total number of times we hit TLP method 2");
1409 	rack_sack_skipped_acked = counter_u64_alloc(M_WAITOK);
1410 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1411 	    SYSCTL_CHILDREN(rack_attack),
1412 	    OID_AUTO, "skipacked", CTLFLAG_RD,
1413 	    &rack_sack_skipped_acked,
1414 	    "Total number of times we skipped previously sacked");
1415 	rack_sack_splits = counter_u64_alloc(M_WAITOK);
1416 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1417 	    SYSCTL_CHILDREN(rack_attack),
1418 	    OID_AUTO, "ofsplit", CTLFLAG_RD,
1419 	    &rack_sack_splits,
1420 	    "Total number of times we did the old fashion tree split");
1421 	rack_progress_drops = counter_u64_alloc(M_WAITOK);
1422 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1423 	    SYSCTL_CHILDREN(rack_counters),
1424 	    OID_AUTO, "prog_drops", CTLFLAG_RD,
1425 	    &rack_progress_drops,
1426 	    "Total number of progress drops");
1427 	rack_input_idle_reduces = counter_u64_alloc(M_WAITOK);
1428 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1429 	    SYSCTL_CHILDREN(rack_counters),
1430 	    OID_AUTO, "idle_reduce_oninput", CTLFLAG_RD,
1431 	    &rack_input_idle_reduces,
1432 	    "Total number of idle reductions on input");
1433 	rack_collapsed_win = counter_u64_alloc(M_WAITOK);
1434 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1435 	    SYSCTL_CHILDREN(rack_counters),
1436 	    OID_AUTO, "collapsed_win", CTLFLAG_RD,
1437 	    &rack_collapsed_win,
1438 	    "Total number of collapsed windows");
1439 	rack_tlp_does_nada = counter_u64_alloc(M_WAITOK);
1440 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1441 	    SYSCTL_CHILDREN(rack_counters),
1442 	    OID_AUTO, "tlp_nada", CTLFLAG_RD,
1443 	    &rack_tlp_does_nada,
1444 	    "Total number of nada tlp calls");
1445 	rack_try_scwnd = counter_u64_alloc(M_WAITOK);
1446 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1447 	    SYSCTL_CHILDREN(rack_counters),
1448 	    OID_AUTO, "tried_scwnd", CTLFLAG_RD,
1449 	    &rack_try_scwnd,
1450 	    "Total number of scwnd attempts");
1451 
1452 	rack_tls_rwnd = counter_u64_alloc(M_WAITOK);
1453 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1454 	    SYSCTL_CHILDREN(rack_counters),
1455 	    OID_AUTO, "tls_rwnd", CTLFLAG_RD,
1456 	    &rack_tls_rwnd,
1457 	    "Total hdwr tls rwnd limited");
1458 	rack_tls_cwnd = counter_u64_alloc(M_WAITOK);
1459 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1460 	    SYSCTL_CHILDREN(rack_counters),
1461 	    OID_AUTO, "tls_cwnd", CTLFLAG_RD,
1462 	    &rack_tls_cwnd,
1463 	    "Total hdwr tls cwnd limited");
1464 	rack_tls_app = counter_u64_alloc(M_WAITOK);
1465 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1466 	    SYSCTL_CHILDREN(rack_counters),
1467 	    OID_AUTO, "tls_app", CTLFLAG_RD,
1468 	    &rack_tls_app,
1469 	    "Total hdwr tls app limited");
1470 	rack_tls_other = counter_u64_alloc(M_WAITOK);
1471 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1472 	    SYSCTL_CHILDREN(rack_counters),
1473 	    OID_AUTO, "tls_other", CTLFLAG_RD,
1474 	    &rack_tls_other,
1475 	    "Total hdwr tls other limited");
1476 	rack_tls_filled = counter_u64_alloc(M_WAITOK);
1477 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1478 	    SYSCTL_CHILDREN(rack_counters),
1479 	    OID_AUTO, "tls_filled", CTLFLAG_RD,
1480 	    &rack_tls_filled,
1481 	    "Total hdwr tls filled");
1482 	rack_tls_rxt = counter_u64_alloc(M_WAITOK);
1483 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1484 	    SYSCTL_CHILDREN(rack_counters),
1485 	    OID_AUTO, "tls_rxt", CTLFLAG_RD,
1486 	    &rack_tls_rxt,
1487 	    "Total hdwr rxt");
1488 	rack_tls_tlp = counter_u64_alloc(M_WAITOK);
1489 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1490 	    SYSCTL_CHILDREN(rack_counters),
1491 	    OID_AUTO, "tls_tlp", CTLFLAG_RD,
1492 	    &rack_tls_tlp,
1493 	    "Total hdwr tls tlp");
1494 	rack_per_timer_hole = counter_u64_alloc(M_WAITOK);
1495 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1496 	    SYSCTL_CHILDREN(rack_counters),
1497 	    OID_AUTO, "timer_hole", CTLFLAG_RD,
1498 	    &rack_per_timer_hole,
1499 	    "Total persists start in timer hole");
1500 	COUNTER_ARRAY_ALLOC(rack_out_size, TCP_MSS_ACCT_SIZE, M_WAITOK);
1501 	SYSCTL_ADD_COUNTER_U64_ARRAY(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root),
1502 	    OID_AUTO, "outsize", CTLFLAG_RD,
1503 	    rack_out_size, TCP_MSS_ACCT_SIZE, "MSS send sizes");
1504 	COUNTER_ARRAY_ALLOC(rack_opts_arry, RACK_OPTS_SIZE, M_WAITOK);
1505 	SYSCTL_ADD_COUNTER_U64_ARRAY(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root),
1506 	    OID_AUTO, "opts", CTLFLAG_RD,
1507 	    rack_opts_arry, RACK_OPTS_SIZE, "RACK Option Stats");
1508 	SYSCTL_ADD_PROC(&rack_sysctl_ctx,
1509 	    SYSCTL_CHILDREN(rack_sysctl_root),
1510 	    OID_AUTO, "clear", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1511 	    &rack_clear_counter, 0, sysctl_rack_clear, "IU", "Clear counters");
1512 }
1513 
1514 static __inline int
1515 rb_map_cmp(struct rack_sendmap *b, struct rack_sendmap *a)
1516 {
1517 	if (SEQ_GEQ(b->r_start, a->r_start) &&
1518 	    SEQ_LT(b->r_start, a->r_end)) {
1519 		/*
1520 		 * The entry b is within the
1521 		 * block a. i.e.:
1522 		 * a --   |-------------|
1523 		 * b --   |----|
1524 		 * <or>
1525 		 * b --       |------|
1526 		 * <or>
1527 		 * b --       |-----------|
1528 		 */
1529 		return (0);
1530 	} else if (SEQ_GEQ(b->r_start, a->r_end)) {
1531 		/*
1532 		 * b falls as either the next
1533 		 * sequence block after a so a
1534 		 * is said to be smaller than b.
1535 		 * i.e:
1536 		 * a --   |------|
1537 		 * b --          |--------|
1538 		 * or
1539 		 * b --              |-----|
1540 		 */
1541 		return (1);
1542 	}
1543 	/*
1544 	 * Whats left is where a is
1545 	 * larger than b. i.e:
1546 	 * a --         |-------|
1547 	 * b --  |---|
1548 	 * or even possibly
1549 	 * b --   |--------------|
1550 	 */
1551 	return (-1);
1552 }
1553 
1554 RB_PROTOTYPE(rack_rb_tree_head, rack_sendmap, r_next, rb_map_cmp);
1555 RB_GENERATE(rack_rb_tree_head, rack_sendmap, r_next, rb_map_cmp);
1556 
1557 static uint32_t
1558 rc_init_window(struct tcp_rack *rack)
1559 {
1560 	uint32_t win;
1561 
1562 	if (rack->rc_init_win == 0) {
1563 		/*
1564 		 * Nothing set by the user, use the system stack
1565 		 * default.
1566 		 */
1567 		return(tcp_compute_initwnd(tcp_maxseg(rack->rc_tp)));
1568 	}
1569 	win = ctf_fixed_maxseg(rack->rc_tp) * rack->rc_init_win;
1570 	return(win);
1571 }
1572 
1573 static uint64_t
1574 rack_get_fixed_pacing_bw(struct tcp_rack *rack)
1575 {
1576 	if (IN_RECOVERY(rack->rc_tp->t_flags))
1577 		return (rack->r_ctl.rc_fixed_pacing_rate_rec);
1578 	else if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh)
1579 		return (rack->r_ctl.rc_fixed_pacing_rate_ss);
1580 	else
1581 		return (rack->r_ctl.rc_fixed_pacing_rate_ca);
1582 }
1583 
1584 static uint64_t
1585 rack_get_bw(struct tcp_rack *rack)
1586 {
1587 	if (rack->use_fixed_rate) {
1588 		/* Return the fixed pacing rate */
1589 		return (rack_get_fixed_pacing_bw(rack));
1590 	}
1591 	if (rack->r_ctl.gp_bw == 0) {
1592 		/*
1593 		 * We have yet no b/w measurement,
1594 		 * if we have a user set initial bw
1595 		 * return it. If we don't have that and
1596 		 * we have an srtt, use the tcp IW (10) to
1597 		 * calculate a fictional b/w over the SRTT
1598 		 * which is more or less a guess. Note
1599 		 * we don't use our IW from rack on purpose
1600 		 * so if we have like IW=30, we are not
1601 		 * calculating a "huge" b/w.
1602 		 */
1603 		uint64_t bw, srtt;
1604 		if (rack->r_ctl.init_rate)
1605 			return (rack->r_ctl.init_rate);
1606 
1607 		/* Has the user set a max peak rate? */
1608 #ifdef NETFLIX_PEAKRATE
1609 		if (rack->rc_tp->t_maxpeakrate)
1610 			return (rack->rc_tp->t_maxpeakrate);
1611 #endif
1612 		/* Ok lets come up with the IW guess, if we have a srtt */
1613 		if (rack->rc_tp->t_srtt == 0) {
1614 			/*
1615 			 * Go with old pacing method
1616 			 * i.e. burst mitigation only.
1617 			 */
1618 			return (0);
1619 		}
1620 		/* Ok lets get the initial TCP win (not racks) */
1621 		bw = tcp_compute_initwnd(tcp_maxseg(rack->rc_tp));
1622 		srtt = ((uint64_t)TICKS_2_USEC(rack->rc_tp->t_srtt) >> TCP_RTT_SHIFT);
1623 		bw *= (uint64_t)USECS_IN_SECOND;
1624 		bw /= srtt;
1625 		return (bw);
1626 	} else {
1627 		uint64_t bw;
1628 
1629 		if(rack->r_ctl.num_avg >= RACK_REQ_AVG) {
1630 			/* Averaging is done, we can return the value */
1631 			bw = rack->r_ctl.gp_bw;
1632 		} else {
1633 			/* Still doing initial average must calculate */
1634 			bw = rack->r_ctl.gp_bw / rack->r_ctl.num_avg;
1635 		}
1636 #ifdef NETFLIX_PEAKRATE
1637 		if ((rack->rc_tp->t_maxpeakrate) &&
1638 		    (bw > rack->rc_tp->t_maxpeakrate)) {
1639 			/* The user has set a peak rate to pace at
1640 			 * don't allow us to pace faster than that.
1641 			 */
1642 			return (rack->rc_tp->t_maxpeakrate);
1643 		}
1644 #endif
1645 		return (bw);
1646 	}
1647 }
1648 
1649 static uint16_t
1650 rack_get_output_gain(struct tcp_rack *rack, struct rack_sendmap *rsm)
1651 {
1652 	if (rack->use_fixed_rate) {
1653 		return (100);
1654 	} else if (rack->in_probe_rtt && (rsm == NULL))
1655 		return(rack->r_ctl.rack_per_of_gp_probertt);
1656 	else if ((IN_RECOVERY(rack->rc_tp->t_flags) &&
1657 		  rack->r_ctl.rack_per_of_gp_rec)) {
1658 		if (rsm) {
1659 			/* a retransmission always use the recovery rate */
1660 			return(rack->r_ctl.rack_per_of_gp_rec);
1661 		} else if (rack->rack_rec_nonrxt_use_cr) {
1662 			/* Directed to use the configured rate */
1663 			goto configured_rate;
1664 		} else if (rack->rack_no_prr &&
1665 			   (rack->r_ctl.rack_per_of_gp_rec > 100)) {
1666 			/* No PRR, lets just use the b/w estimate only */
1667 			return(100);
1668 		} else {
1669 			/*
1670 			 * Here we may have a non-retransmit but we
1671 			 * have no overrides, so just use the recovery
1672 			 * rate (prr is in effect).
1673 			 */
1674 			return(rack->r_ctl.rack_per_of_gp_rec);
1675 		}
1676 	}
1677 configured_rate:
1678 	/* For the configured rate we look at our cwnd vs the ssthresh */
1679 	if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh)
1680 		return (rack->r_ctl.rack_per_of_gp_ss);
1681 	else
1682 		return(rack->r_ctl.rack_per_of_gp_ca);
1683 }
1684 
1685 static uint64_t
1686 rack_get_output_bw(struct tcp_rack *rack, uint64_t bw, struct rack_sendmap *rsm)
1687 {
1688 	/*
1689 	 * We allow rack_per_of_gp_xx to dictate our bw rate we want.
1690 	 */
1691 	uint64_t bw_est;
1692 	uint64_t gain;
1693 
1694 	gain = (uint64_t)rack_get_output_gain(rack, rsm);
1695 	bw_est = bw * gain;
1696 	bw_est /= (uint64_t)100;
1697 	/* Never fall below the minimum (def 64kbps) */
1698 	if (bw_est < RACK_MIN_BW)
1699 		bw_est = RACK_MIN_BW;
1700 	return (bw_est);
1701 }
1702 
1703 static void
1704 rack_log_retran_reason(struct tcp_rack *rack, struct rack_sendmap *rsm, uint32_t tsused, uint32_t thresh, int mod)
1705 {
1706 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1707 		union tcp_log_stackspecific log;
1708 		struct timeval tv;
1709 
1710 		if ((mod != 1) && (rack_verbose_logging == 0)) {
1711 			/*
1712 			 * We get 3 values currently for mod
1713 			 * 1 - We are retransmitting and this tells the reason.
1714 			 * 2 - We are clearing a dup-ack count.
1715 			 * 3 - We are incrementing a dup-ack count.
1716 			 *
1717 			 * The clear/increment are only logged
1718 			 * if you have BBverbose on.
1719 			 */
1720 			return;
1721 		}
1722 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1723 		log.u_bbr.flex1 = tsused;
1724 		log.u_bbr.flex2 = thresh;
1725 		log.u_bbr.flex3 = rsm->r_flags;
1726 		log.u_bbr.flex4 = rsm->r_dupack;
1727 		log.u_bbr.flex5 = rsm->r_start;
1728 		log.u_bbr.flex6 = rsm->r_end;
1729 		log.u_bbr.flex8 = mod;
1730 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1731 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1732 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1733 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1734 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1735 		    &rack->rc_inp->inp_socket->so_rcv,
1736 		    &rack->rc_inp->inp_socket->so_snd,
1737 		    BBR_LOG_SETTINGS_CHG, 0,
1738 		    0, &log, false, &tv);
1739 	}
1740 }
1741 
1742 
1743 
1744 static void
1745 rack_log_to_start(struct tcp_rack *rack, uint32_t cts, uint32_t to, int32_t slot, uint8_t which)
1746 {
1747 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1748 		union tcp_log_stackspecific log;
1749 		struct timeval tv;
1750 
1751 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1752 		log.u_bbr.flex1 = TICKS_2_MSEC(rack->rc_tp->t_srtt >> TCP_RTT_SHIFT);
1753 		log.u_bbr.flex2 = to * 1000;
1754 		log.u_bbr.flex3 = rack->r_ctl.rc_hpts_flags;
1755 		log.u_bbr.flex4 = slot;
1756 		log.u_bbr.flex5 = rack->rc_inp->inp_hptsslot;
1757 		log.u_bbr.flex6 = rack->rc_tp->t_rxtcur;
1758 		log.u_bbr.flex7 = rack->rc_in_persist;
1759 		log.u_bbr.flex8 = which;
1760 		if (rack->rack_no_prr)
1761 			log.u_bbr.pkts_out = 0;
1762 		else
1763 			log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
1764 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1765 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1766 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1767 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1768 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1769 		    &rack->rc_inp->inp_socket->so_rcv,
1770 		    &rack->rc_inp->inp_socket->so_snd,
1771 		    BBR_LOG_TIMERSTAR, 0,
1772 		    0, &log, false, &tv);
1773 	}
1774 }
1775 
1776 static void
1777 rack_log_to_event(struct tcp_rack *rack, int32_t to_num, struct rack_sendmap *rsm)
1778 {
1779 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1780 		union tcp_log_stackspecific log;
1781 		struct timeval tv;
1782 
1783 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1784 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1785 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1786 		log.u_bbr.flex8 = to_num;
1787 		log.u_bbr.flex1 = rack->r_ctl.rc_rack_min_rtt;
1788 		log.u_bbr.flex2 = rack->rc_rack_rtt;
1789 		if (rsm == NULL)
1790 			log.u_bbr.flex3 = 0;
1791 		else
1792 			log.u_bbr.flex3 = rsm->r_end - rsm->r_start;
1793 		if (rack->rack_no_prr)
1794 			log.u_bbr.flex5 = 0;
1795 		else
1796 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
1797 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1798 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1799 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1800 		    &rack->rc_inp->inp_socket->so_rcv,
1801 		    &rack->rc_inp->inp_socket->so_snd,
1802 		    BBR_LOG_RTO, 0,
1803 		    0, &log, false, &tv);
1804 	}
1805 }
1806 
1807 static void
1808 rack_log_rtt_upd(struct tcpcb *tp, struct tcp_rack *rack, uint32_t t, uint32_t len,
1809 		 struct rack_sendmap *rsm, int conf)
1810 {
1811 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
1812 		union tcp_log_stackspecific log;
1813 		struct timeval tv;
1814 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1815 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1816 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1817 		log.u_bbr.flex1 = t;
1818 		log.u_bbr.flex2 = len;
1819 		log.u_bbr.flex3 = rack->r_ctl.rc_rack_min_rtt * HPTS_USEC_IN_MSEC;
1820 		log.u_bbr.flex4 = rack->r_ctl.rack_rs.rs_rtt_lowest * HPTS_USEC_IN_MSEC;
1821 		log.u_bbr.flex5 = rack->r_ctl.rack_rs.rs_rtt_highest * HPTS_USEC_IN_MSEC;
1822 		log.u_bbr.flex6 = rack->r_ctl.rack_rs.rs_rtt_cnt;
1823 		log.u_bbr.flex7 = conf;
1824 		log.u_bbr.rttProp = (uint64_t)rack->r_ctl.rack_rs.rs_rtt_tot * (uint64_t)HPTS_USEC_IN_MSEC;
1825 		log.u_bbr.flex8 = rack->r_ctl.rc_rate_sample_method;
1826 		if (rack->rack_no_prr)
1827 			log.u_bbr.pkts_out = 0;
1828 		else
1829 			log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
1830 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1831 		log.u_bbr.delivered = rack->r_ctl.rack_rs.rs_us_rtt;
1832 		log.u_bbr.pkts_out = rack->r_ctl.rack_rs.rs_flags;
1833 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1834 		if (rsm) {
1835 			log.u_bbr.pkt_epoch = rsm->r_start;
1836 			log.u_bbr.lost = rsm->r_end;
1837 			log.u_bbr.cwnd_gain = rsm->r_rtr_cnt;
1838 		} else {
1839 
1840 			/* Its a SYN */
1841 			log.u_bbr.pkt_epoch = rack->rc_tp->iss;
1842 			log.u_bbr.lost = 0;
1843 			log.u_bbr.cwnd_gain = 0;
1844 		}
1845 		/* Write out general bits of interest rrs here */
1846 		log.u_bbr.use_lt_bw = rack->rc_highly_buffered;
1847 		log.u_bbr.use_lt_bw <<= 1;
1848 		log.u_bbr.use_lt_bw |= rack->forced_ack;
1849 		log.u_bbr.use_lt_bw <<= 1;
1850 		log.u_bbr.use_lt_bw |= rack->rc_gp_dyn_mul;
1851 		log.u_bbr.use_lt_bw <<= 1;
1852 		log.u_bbr.use_lt_bw |= rack->in_probe_rtt;
1853 		log.u_bbr.use_lt_bw <<= 1;
1854 		log.u_bbr.use_lt_bw |= rack->measure_saw_probe_rtt;
1855 		log.u_bbr.use_lt_bw <<= 1;
1856 		log.u_bbr.use_lt_bw |= rack->app_limited_needs_set;
1857 		log.u_bbr.use_lt_bw <<= 1;
1858 		log.u_bbr.use_lt_bw |= rack->rc_gp_filled;
1859 		log.u_bbr.use_lt_bw <<= 1;
1860 		log.u_bbr.use_lt_bw |= rack->rc_dragged_bottom;
1861 		log.u_bbr.applimited = rack->r_ctl.rc_target_probertt_flight;
1862 		log.u_bbr.epoch = rack->r_ctl.rc_time_probertt_starts;
1863 		log.u_bbr.lt_epoch = rack->r_ctl.rc_time_probertt_entered;
1864 		log.u_bbr.cur_del_rate = rack->r_ctl.rc_lower_rtt_us_cts;
1865 		log.u_bbr.delRate = rack->r_ctl.rc_gp_srtt;
1866 		TCP_LOG_EVENTP(tp, NULL,
1867 		    &rack->rc_inp->inp_socket->so_rcv,
1868 		    &rack->rc_inp->inp_socket->so_snd,
1869 		    BBR_LOG_BBRRTT, 0,
1870 		    0, &log, false, &tv);
1871 	}
1872 }
1873 
1874 static void
1875 rack_log_rtt_sample(struct tcp_rack *rack, uint32_t rtt)
1876 {
1877 	/*
1878 	 * Log the rtt sample we are
1879 	 * applying to the srtt algorithm in
1880 	 * useconds.
1881 	 */
1882 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1883 		union tcp_log_stackspecific log;
1884 		struct timeval tv;
1885 
1886 		/* Convert our ms to a microsecond */
1887 		memset(&log, 0, sizeof(log));
1888 		log.u_bbr.flex1 = rtt * 1000;
1889 		log.u_bbr.flex2 = rack->r_ctl.ack_count;
1890 		log.u_bbr.flex3 = rack->r_ctl.sack_count;
1891 		log.u_bbr.flex4 = rack->r_ctl.sack_noextra_move;
1892 		log.u_bbr.flex5 = rack->r_ctl.sack_moved_extra;
1893 		log.u_bbr.flex8 = rack->sack_attack_disable;
1894 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1895 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1896 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1897 		    &rack->rc_inp->inp_socket->so_rcv,
1898 		    &rack->rc_inp->inp_socket->so_snd,
1899 		    TCP_LOG_RTT, 0,
1900 		    0, &log, false, &tv);
1901 	}
1902 }
1903 
1904 
1905 static inline void
1906 rack_log_progress_event(struct tcp_rack *rack, struct tcpcb *tp, uint32_t tick,  int event, int line)
1907 {
1908 	if (rack_verbose_logging && (tp->t_logstate != TCP_LOG_STATE_OFF)) {
1909 		union tcp_log_stackspecific log;
1910 		struct timeval tv;
1911 
1912 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1913 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1914 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1915 		log.u_bbr.flex1 = line;
1916 		log.u_bbr.flex2 = tick;
1917 		log.u_bbr.flex3 = tp->t_maxunacktime;
1918 		log.u_bbr.flex4 = tp->t_acktime;
1919 		log.u_bbr.flex8 = event;
1920 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1921 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1922 		TCP_LOG_EVENTP(tp, NULL,
1923 		    &rack->rc_inp->inp_socket->so_rcv,
1924 		    &rack->rc_inp->inp_socket->so_snd,
1925 		    BBR_LOG_PROGRESS, 0,
1926 		    0, &log, false, &tv);
1927 	}
1928 }
1929 
1930 static void
1931 rack_log_type_bbrsnd(struct tcp_rack *rack, uint32_t len, uint32_t slot, uint32_t cts, struct timeval *tv)
1932 {
1933 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1934 		union tcp_log_stackspecific log;
1935 
1936 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1937 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1938 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1939 		log.u_bbr.flex1 = slot;
1940 		if (rack->rack_no_prr)
1941 			log.u_bbr.flex2 = 0;
1942 		else
1943 			log.u_bbr.flex2 = rack->r_ctl.rc_prr_sndcnt;
1944 		log.u_bbr.flex7 = (0x0000ffff & rack->r_ctl.rc_hpts_flags);
1945 		log.u_bbr.flex8 = rack->rc_in_persist;
1946 		log.u_bbr.timeStamp = cts;
1947 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1948 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1949 		    &rack->rc_inp->inp_socket->so_rcv,
1950 		    &rack->rc_inp->inp_socket->so_snd,
1951 		    BBR_LOG_BBRSND, 0,
1952 		    0, &log, false, tv);
1953 	}
1954 }
1955 
1956 static void
1957 rack_log_doseg_done(struct tcp_rack *rack, uint32_t cts, int32_t nxt_pkt, int32_t did_out, int way_out)
1958 {
1959 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1960 		union tcp_log_stackspecific log;
1961 		struct timeval tv;
1962 
1963 		memset(&log, 0, sizeof(log));
1964 		log.u_bbr.flex1 = did_out;
1965 		log.u_bbr.flex2 = nxt_pkt;
1966 		log.u_bbr.flex3 = way_out;
1967 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
1968 		if (rack->rack_no_prr)
1969 			log.u_bbr.flex5 = 0;
1970 		else
1971 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
1972 		log.u_bbr.applimited = rack->r_ctl.rc_pace_min_segs;
1973 		log.u_bbr.flex7 = rack->r_wanted_output;
1974 		log.u_bbr.flex8 = rack->rc_in_persist;
1975 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1976 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1977 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1978 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1979 		    &rack->rc_inp->inp_socket->so_rcv,
1980 		    &rack->rc_inp->inp_socket->so_snd,
1981 		    BBR_LOG_DOSEG_DONE, 0,
1982 		    0, &log, false, &tv);
1983 	}
1984 }
1985 
1986 static void
1987 rack_log_type_hrdwtso(struct tcpcb *tp, struct tcp_rack *rack, int len, int mod, int32_t orig_len, int frm)
1988 {
1989 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
1990 		union tcp_log_stackspecific log;
1991 		struct timeval tv;
1992 		uint32_t cts;
1993 
1994 		memset(&log, 0, sizeof(log));
1995 		cts = tcp_get_usecs(&tv);
1996 		log.u_bbr.flex1 = rack->r_ctl.rc_pace_min_segs;
1997 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
1998 		log.u_bbr.flex4 = len;
1999 		log.u_bbr.flex5 = orig_len;
2000 		log.u_bbr.flex6 = rack->r_ctl.rc_sacked;
2001 		log.u_bbr.flex7 = mod;
2002 		log.u_bbr.flex8 = frm;
2003 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2004 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2005 		TCP_LOG_EVENTP(tp, NULL,
2006 		    &tp->t_inpcb->inp_socket->so_rcv,
2007 		    &tp->t_inpcb->inp_socket->so_snd,
2008 		    TCP_HDWR_TLS, 0,
2009 		    0, &log, false, &tv);
2010 	}
2011 }
2012 
2013 static void
2014 rack_log_type_just_return(struct tcp_rack *rack, uint32_t cts, uint32_t tlen, uint32_t slot,
2015 			  uint8_t hpts_calling, int reason, uint32_t cwnd_to_use)
2016 {
2017 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2018 		union tcp_log_stackspecific log;
2019 		struct timeval tv;
2020 
2021 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2022 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
2023 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
2024 		log.u_bbr.flex1 = slot;
2025 		log.u_bbr.flex2 = rack->r_ctl.rc_hpts_flags;
2026 		log.u_bbr.flex4 = reason;
2027 		if (rack->rack_no_prr)
2028 			log.u_bbr.flex5 = 0;
2029 		else
2030 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
2031 		log.u_bbr.flex7 = hpts_calling;
2032 		log.u_bbr.flex8 = rack->rc_in_persist;
2033 		log.u_bbr.lt_epoch = cwnd_to_use;
2034 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2035 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2036 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2037 		    &rack->rc_inp->inp_socket->so_rcv,
2038 		    &rack->rc_inp->inp_socket->so_snd,
2039 		    BBR_LOG_JUSTRET, 0,
2040 		    tlen, &log, false, &tv);
2041 	}
2042 }
2043 
2044 static void
2045 rack_log_to_cancel(struct tcp_rack *rack, int32_t hpts_removed, int line, uint32_t us_cts,
2046 		   struct timeval *tv, uint32_t flags_on_entry)
2047 {
2048 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2049 		union tcp_log_stackspecific log;
2050 
2051 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2052 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
2053 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
2054 		log.u_bbr.flex1 = line;
2055 		log.u_bbr.flex2 = rack->r_ctl.rc_last_output_to;
2056 		log.u_bbr.flex3 = flags_on_entry;
2057 		log.u_bbr.flex4 = us_cts;
2058 		if (rack->rack_no_prr)
2059 			log.u_bbr.flex5 = 0;
2060 		else
2061 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
2062 		log.u_bbr.flex6 = rack->rc_tp->t_rxtcur;
2063 		log.u_bbr.flex7 = hpts_removed;
2064 		log.u_bbr.flex8 = 1;
2065 		log.u_bbr.applimited = rack->r_ctl.rc_hpts_flags;
2066 		log.u_bbr.timeStamp = us_cts;
2067 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2068 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2069 		    &rack->rc_inp->inp_socket->so_rcv,
2070 		    &rack->rc_inp->inp_socket->so_snd,
2071 		    BBR_LOG_TIMERCANC, 0,
2072 		    0, &log, false, tv);
2073 	}
2074 }
2075 
2076 static void
2077 rack_log_alt_to_to_cancel(struct tcp_rack *rack,
2078 			  uint32_t flex1, uint32_t flex2,
2079 			  uint32_t flex3, uint32_t flex4,
2080 			  uint32_t flex5, uint32_t flex6,
2081 			  uint16_t flex7, uint8_t mod)
2082 {
2083 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2084 		union tcp_log_stackspecific log;
2085 		struct timeval tv;
2086 
2087 		if (mod == 1) {
2088 			/* No you can't use 1, its for the real to cancel */
2089 			return;
2090 		}
2091 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2092 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2093 		log.u_bbr.flex1 = flex1;
2094 		log.u_bbr.flex2 = flex2;
2095 		log.u_bbr.flex3 = flex3;
2096 		log.u_bbr.flex4 = flex4;
2097 		log.u_bbr.flex5 = flex5;
2098 		log.u_bbr.flex6 = flex6;
2099 		log.u_bbr.flex7 = flex7;
2100 		log.u_bbr.flex8 =  mod;
2101 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2102 		    &rack->rc_inp->inp_socket->so_rcv,
2103 		    &rack->rc_inp->inp_socket->so_snd,
2104 		    BBR_LOG_TIMERCANC, 0,
2105 		    0, &log, false, &tv);
2106 	}
2107 }
2108 
2109 static void
2110 rack_log_to_processing(struct tcp_rack *rack, uint32_t cts, int32_t ret, int32_t timers)
2111 {
2112 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2113 		union tcp_log_stackspecific log;
2114 		struct timeval tv;
2115 
2116 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2117 		log.u_bbr.flex1 = timers;
2118 		log.u_bbr.flex2 = ret;
2119 		log.u_bbr.flex3 = rack->r_ctl.rc_timer_exp;
2120 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
2121 		log.u_bbr.flex5 = cts;
2122 		if (rack->rack_no_prr)
2123 			log.u_bbr.flex6 = 0;
2124 		else
2125 			log.u_bbr.flex6 = rack->r_ctl.rc_prr_sndcnt;
2126 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2127 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2128 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2129 		    &rack->rc_inp->inp_socket->so_rcv,
2130 		    &rack->rc_inp->inp_socket->so_snd,
2131 		    BBR_LOG_TO_PROCESS, 0,
2132 		    0, &log, false, &tv);
2133 	}
2134 }
2135 
2136 static void
2137 rack_log_to_prr(struct tcp_rack *rack, int frm, int orig_cwnd)
2138 {
2139 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2140 		union tcp_log_stackspecific log;
2141 		struct timeval tv;
2142 
2143 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2144 		log.u_bbr.flex1 = rack->r_ctl.rc_prr_out;
2145 		log.u_bbr.flex2 = rack->r_ctl.rc_prr_recovery_fs;
2146 		if (rack->rack_no_prr)
2147 			log.u_bbr.flex3 = 0;
2148 		else
2149 			log.u_bbr.flex3 = rack->r_ctl.rc_prr_sndcnt;
2150 		log.u_bbr.flex4 = rack->r_ctl.rc_prr_delivered;
2151 		log.u_bbr.flex5 = rack->r_ctl.rc_sacked;
2152 		log.u_bbr.flex6 = rack->r_ctl.rc_holes_rxt;
2153 		log.u_bbr.flex8 = frm;
2154 		log.u_bbr.pkts_out = orig_cwnd;
2155 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2156 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2157 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2158 		    &rack->rc_inp->inp_socket->so_rcv,
2159 		    &rack->rc_inp->inp_socket->so_snd,
2160 		    BBR_LOG_BBRUPD, 0,
2161 		    0, &log, false, &tv);
2162 	}
2163 }
2164 
2165 #ifdef NETFLIX_EXP_DETECTION
2166 static void
2167 rack_log_sad(struct tcp_rack *rack, int event)
2168 {
2169 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2170 		union tcp_log_stackspecific log;
2171 		struct timeval tv;
2172 
2173 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2174 		log.u_bbr.flex1 = rack->r_ctl.sack_count;
2175 		log.u_bbr.flex2 = rack->r_ctl.ack_count;
2176 		log.u_bbr.flex3 = rack->r_ctl.sack_moved_extra;
2177 		log.u_bbr.flex4 = rack->r_ctl.sack_noextra_move;
2178 		log.u_bbr.flex5 = rack->r_ctl.rc_num_maps_alloced;
2179 		log.u_bbr.flex6 = tcp_sack_to_ack_thresh;
2180 		log.u_bbr.pkts_out = tcp_sack_to_move_thresh;
2181 		log.u_bbr.lt_epoch = (tcp_force_detection << 8);
2182 		log.u_bbr.lt_epoch |= rack->do_detection;
2183 		log.u_bbr.applimited = tcp_map_minimum;
2184 		log.u_bbr.flex7 = rack->sack_attack_disable;
2185 		log.u_bbr.flex8 = event;
2186 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2187 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2188 		log.u_bbr.delivered = tcp_sad_decay_val;
2189 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2190 		    &rack->rc_inp->inp_socket->so_rcv,
2191 		    &rack->rc_inp->inp_socket->so_snd,
2192 		    TCP_SAD_DETECTION, 0,
2193 		    0, &log, false, &tv);
2194 	}
2195 }
2196 #endif
2197 
2198 static void
2199 rack_counter_destroy(void)
2200 {
2201 	counter_u64_free(rack_ack_total);
2202 	counter_u64_free(rack_express_sack);
2203 	counter_u64_free(rack_sack_total);
2204 	counter_u64_free(rack_move_none);
2205 	counter_u64_free(rack_move_some);
2206 	counter_u64_free(rack_sack_attacks_detected);
2207 	counter_u64_free(rack_sack_attacks_reversed);
2208 	counter_u64_free(rack_sack_used_next_merge);
2209 	counter_u64_free(rack_sack_used_prev_merge);
2210 	counter_u64_free(rack_badfr);
2211 	counter_u64_free(rack_badfr_bytes);
2212 	counter_u64_free(rack_rtm_prr_retran);
2213 	counter_u64_free(rack_rtm_prr_newdata);
2214 	counter_u64_free(rack_timestamp_mismatch);
2215 	counter_u64_free(rack_find_high);
2216 	counter_u64_free(rack_reorder_seen);
2217 	counter_u64_free(rack_tlp_tot);
2218 	counter_u64_free(rack_tlp_newdata);
2219 	counter_u64_free(rack_tlp_retran);
2220 	counter_u64_free(rack_tlp_retran_bytes);
2221 	counter_u64_free(rack_tlp_retran_fail);
2222 	counter_u64_free(rack_to_tot);
2223 	counter_u64_free(rack_to_arm_rack);
2224 	counter_u64_free(rack_to_arm_tlp);
2225 	counter_u64_free(rack_calc_zero);
2226 	counter_u64_free(rack_calc_nonzero);
2227 	counter_u64_free(rack_paced_segments);
2228 	counter_u64_free(rack_unpaced_segments);
2229 	counter_u64_free(rack_saw_enobuf);
2230 	counter_u64_free(rack_saw_enetunreach);
2231 	counter_u64_free(rack_to_alloc);
2232 	counter_u64_free(rack_to_alloc_hard);
2233 	counter_u64_free(rack_to_alloc_emerg);
2234 	counter_u64_free(rack_to_alloc_limited);
2235 	counter_u64_free(rack_alloc_limited_conns);
2236 	counter_u64_free(rack_split_limited);
2237 	counter_u64_free(rack_sack_proc_all);
2238 	counter_u64_free(rack_sack_proc_restart);
2239 	counter_u64_free(rack_sack_proc_short);
2240 	counter_u64_free(rack_enter_tlp_calc);
2241 	counter_u64_free(rack_used_tlpmethod);
2242 	counter_u64_free(rack_used_tlpmethod2);
2243 	counter_u64_free(rack_sack_skipped_acked);
2244 	counter_u64_free(rack_sack_splits);
2245 	counter_u64_free(rack_progress_drops);
2246 	counter_u64_free(rack_input_idle_reduces);
2247 	counter_u64_free(rack_collapsed_win);
2248 	counter_u64_free(rack_tlp_does_nada);
2249 	counter_u64_free(rack_try_scwnd);
2250 	counter_u64_free(rack_tls_rwnd);
2251 	counter_u64_free(rack_tls_cwnd);
2252 	counter_u64_free(rack_tls_app);
2253 	counter_u64_free(rack_tls_other);
2254 	counter_u64_free(rack_tls_filled);
2255 	counter_u64_free(rack_tls_rxt);
2256 	counter_u64_free(rack_tls_tlp);
2257 	counter_u64_free(rack_per_timer_hole);
2258 	COUNTER_ARRAY_FREE(rack_out_size, TCP_MSS_ACCT_SIZE);
2259 	COUNTER_ARRAY_FREE(rack_opts_arry, RACK_OPTS_SIZE);
2260 }
2261 
2262 static struct rack_sendmap *
2263 rack_alloc(struct tcp_rack *rack)
2264 {
2265 	struct rack_sendmap *rsm;
2266 
2267 	rsm = uma_zalloc(rack_zone, M_NOWAIT);
2268 	if (rsm) {
2269 		rack->r_ctl.rc_num_maps_alloced++;
2270 		counter_u64_add(rack_to_alloc, 1);
2271 		return (rsm);
2272 	}
2273 	if (rack->rc_free_cnt) {
2274 		counter_u64_add(rack_to_alloc_emerg, 1);
2275 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
2276 		TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
2277 		rack->rc_free_cnt--;
2278 		return (rsm);
2279 	}
2280 	return (NULL);
2281 }
2282 
2283 static struct rack_sendmap *
2284 rack_alloc_full_limit(struct tcp_rack *rack)
2285 {
2286 	if ((V_tcp_map_entries_limit > 0) &&
2287 	    (rack->do_detection == 0) &&
2288 	    (rack->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
2289 		counter_u64_add(rack_to_alloc_limited, 1);
2290 		if (!rack->alloc_limit_reported) {
2291 			rack->alloc_limit_reported = 1;
2292 			counter_u64_add(rack_alloc_limited_conns, 1);
2293 		}
2294 		return (NULL);
2295 	}
2296 	return (rack_alloc(rack));
2297 }
2298 
2299 /* wrapper to allocate a sendmap entry, subject to a specific limit */
2300 static struct rack_sendmap *
2301 rack_alloc_limit(struct tcp_rack *rack, uint8_t limit_type)
2302 {
2303 	struct rack_sendmap *rsm;
2304 
2305 	if (limit_type) {
2306 		/* currently there is only one limit type */
2307 		if (V_tcp_map_split_limit > 0 &&
2308 		    (rack->do_detection == 0) &&
2309 		    rack->r_ctl.rc_num_split_allocs >= V_tcp_map_split_limit) {
2310 			counter_u64_add(rack_split_limited, 1);
2311 			if (!rack->alloc_limit_reported) {
2312 				rack->alloc_limit_reported = 1;
2313 				counter_u64_add(rack_alloc_limited_conns, 1);
2314 			}
2315 			return (NULL);
2316 		}
2317 	}
2318 
2319 	/* allocate and mark in the limit type, if set */
2320 	rsm = rack_alloc(rack);
2321 	if (rsm != NULL && limit_type) {
2322 		rsm->r_limit_type = limit_type;
2323 		rack->r_ctl.rc_num_split_allocs++;
2324 	}
2325 	return (rsm);
2326 }
2327 
2328 static void
2329 rack_free(struct tcp_rack *rack, struct rack_sendmap *rsm)
2330 {
2331 	if (rsm->r_flags & RACK_APP_LIMITED) {
2332 		if (rack->r_ctl.rc_app_limited_cnt > 0) {
2333 			rack->r_ctl.rc_app_limited_cnt--;
2334 		}
2335 	}
2336 	if (rsm->r_limit_type) {
2337 		/* currently there is only one limit type */
2338 		rack->r_ctl.rc_num_split_allocs--;
2339 	}
2340 	if (rsm == rack->r_ctl.rc_first_appl) {
2341 		if (rack->r_ctl.rc_app_limited_cnt == 0)
2342 			rack->r_ctl.rc_first_appl = NULL;
2343 		else {
2344 			/* Follow the next one out */
2345 			struct rack_sendmap fe;
2346 
2347 			fe.r_start = rsm->r_nseq_appl;
2348 			rack->r_ctl.rc_first_appl = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
2349 		}
2350 	}
2351 	if (rsm == rack->r_ctl.rc_resend)
2352 		rack->r_ctl.rc_resend = NULL;
2353 	if (rsm == rack->r_ctl.rc_rsm_at_retran)
2354 		rack->r_ctl.rc_rsm_at_retran = NULL;
2355 	if (rsm == rack->r_ctl.rc_end_appl)
2356 		rack->r_ctl.rc_end_appl = NULL;
2357 	if (rack->r_ctl.rc_tlpsend == rsm)
2358 		rack->r_ctl.rc_tlpsend = NULL;
2359 	if (rack->r_ctl.rc_sacklast == rsm)
2360 		rack->r_ctl.rc_sacklast = NULL;
2361 	if (rack->rc_free_cnt < rack_free_cache) {
2362 		memset(rsm, 0, sizeof(struct rack_sendmap));
2363 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_free, rsm, r_tnext);
2364 		rsm->r_limit_type = 0;
2365 		rack->rc_free_cnt++;
2366 		return;
2367 	}
2368 	rack->r_ctl.rc_num_maps_alloced--;
2369 	uma_zfree(rack_zone, rsm);
2370 }
2371 
2372 static uint32_t
2373 rack_get_measure_window(struct tcpcb *tp, struct tcp_rack *rack)
2374 {
2375 	uint64_t srtt, bw, len, tim;
2376 	uint32_t segsiz, def_len, minl;
2377 
2378 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
2379 	def_len = rack_def_data_window * segsiz;
2380 	if (rack->rc_gp_filled == 0) {
2381 		/*
2382 		 * We have no measurement (IW is in flight?) so
2383 		 * we can only guess using our data_window sysctl
2384 		 * value (usually 100MSS).
2385 		 */
2386 		return (def_len);
2387 	}
2388 	/*
2389 	 * Now we have a number of factors to consider.
2390 	 *
2391 	 * 1) We have a desired BDP which is usually
2392 	 *    at least 2.
2393 	 * 2) We have a minimum number of rtt's usually 1 SRTT
2394 	 *    but we allow it too to be more.
2395 	 * 3) We want to make sure a measurement last N useconds (if
2396 	 *    we have set rack_min_measure_usec.
2397 	 *
2398 	 * We handle the first concern here by trying to create a data
2399 	 * window of max(rack_def_data_window, DesiredBDP). The
2400 	 * second concern we handle in not letting the measurement
2401 	 * window end normally until at least the required SRTT's
2402 	 * have gone by which is done further below in
2403 	 * rack_enough_for_measurement(). Finally the third concern
2404 	 * we also handle here by calculating how long that time
2405 	 * would take at the current BW and then return the
2406 	 * max of our first calculation and that length. Note
2407 	 * that if rack_min_measure_usec is 0, we don't deal
2408 	 * with concern 3. Also for both Concern 1 and 3 an
2409 	 * application limited period could end the measurement
2410 	 * earlier.
2411 	 *
2412 	 * So lets calculate the BDP with the "known" b/w using
2413 	 * the SRTT has our rtt and then multiply it by the
2414 	 * goal.
2415 	 */
2416 	bw = rack_get_bw(rack);
2417 	srtt = ((uint64_t)TICKS_2_USEC(tp->t_srtt) >> TCP_RTT_SHIFT);
2418 	len = bw * srtt;
2419 	len /= (uint64_t)HPTS_USEC_IN_SEC;
2420 	len *= max(1, rack_goal_bdp);
2421         /* Now we need to round up to the nearest MSS */
2422 	len = roundup(len, segsiz);
2423 	if (rack_min_measure_usec) {
2424 		/* Now calculate our min length for this b/w */
2425 		tim = rack_min_measure_usec;
2426 		minl = (tim * bw) / (uint64_t)HPTS_USEC_IN_SEC;
2427 		if (minl == 0)
2428 			minl = 1;
2429 		minl = roundup(minl, segsiz);
2430 		if (len < minl)
2431 			len = minl;
2432 	}
2433 	/*
2434 	 * Now if we have a very small window we want
2435 	 * to attempt to get the window that is
2436 	 * as small as possible. This happens on
2437 	 * low b/w connections and we don't want to
2438 	 * span huge numbers of rtt's between measurements.
2439 	 *
2440 	 * We basically include 2 over our "MIN window" so
2441 	 * that the measurement can be shortened (possibly) by
2442 	 * an ack'ed packet.
2443 	 */
2444 	if (len < def_len)
2445 		return (max((uint32_t)len, ((MIN_GP_WIN+2) * segsiz)));
2446 	else
2447 		return (max((uint32_t)len, def_len));
2448 
2449 }
2450 
2451 static int
2452 rack_enough_for_measurement(struct tcpcb *tp, struct tcp_rack *rack, tcp_seq th_ack)
2453 {
2454 	uint32_t tim, srtts, segsiz;
2455 
2456 	/*
2457 	 * Has enough time passed for the GP measurement to be valid?
2458 	 */
2459 	if ((tp->snd_max == tp->snd_una) ||
2460 	    (th_ack == tp->snd_max)){
2461 		/* All is acked */
2462 		return (1);
2463 	}
2464 	if (SEQ_LT(th_ack, tp->gput_seq)) {
2465 		/* Not enough bytes yet */
2466 		return (0);
2467 	}
2468 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
2469 	if (SEQ_LT(th_ack, tp->gput_ack) &&
2470 	    ((th_ack - tp->gput_seq) < max(rc_init_window(rack), (MIN_GP_WIN * segsiz)))) {
2471 		/* Not enough bytes yet */
2472 		return (0);
2473 	}
2474 	if (rack->r_ctl.rc_first_appl &&
2475 	    (rack->r_ctl.rc_first_appl->r_start == th_ack)) {
2476 		/*
2477 		 * We are up to the app limited point
2478 		 * we have to measure irrespective of the time..
2479 		 */
2480 		return (1);
2481 	}
2482 	/* Now what about time? */
2483 	srtts = (rack->r_ctl.rc_gp_srtt * rack_min_srtts);
2484 	tim = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time) - tp->gput_ts;
2485 	if (tim >= srtts) {
2486 		return (1);
2487 	}
2488 	/* Nope not even a full SRTT has passed */
2489 	return (0);
2490 }
2491 
2492 
2493 static void
2494 rack_log_timely(struct tcp_rack *rack,
2495 		uint32_t logged, uint64_t cur_bw, uint64_t low_bnd,
2496 		uint64_t up_bnd, int line, uint8_t method)
2497 {
2498 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2499 		union tcp_log_stackspecific log;
2500 		struct timeval tv;
2501 
2502 		memset(&log, 0, sizeof(log));
2503 		log.u_bbr.flex1 = logged;
2504 		log.u_bbr.flex2 = rack->rc_gp_timely_inc_cnt;
2505 		log.u_bbr.flex2 <<= 4;
2506 		log.u_bbr.flex2 |= rack->rc_gp_timely_dec_cnt;
2507 		log.u_bbr.flex2 <<= 4;
2508 		log.u_bbr.flex2 |= rack->rc_gp_incr;
2509 		log.u_bbr.flex2 <<= 4;
2510 		log.u_bbr.flex2 |= rack->rc_gp_bwred;
2511 		log.u_bbr.flex3 = rack->rc_gp_incr;
2512 		log.u_bbr.flex4 = rack->r_ctl.rack_per_of_gp_ss;
2513 		log.u_bbr.flex5 = rack->r_ctl.rack_per_of_gp_ca;
2514 		log.u_bbr.flex6 = rack->r_ctl.rack_per_of_gp_rec;
2515 		log.u_bbr.flex7 = rack->rc_gp_bwred;
2516 		log.u_bbr.flex8 = method;
2517 		log.u_bbr.cur_del_rate = cur_bw;
2518 		log.u_bbr.delRate = low_bnd;
2519 		log.u_bbr.bw_inuse = up_bnd;
2520 		log.u_bbr.rttProp = rack_get_bw(rack);
2521 		log.u_bbr.pkt_epoch = line;
2522 		log.u_bbr.pkts_out = rack->r_ctl.rc_rtt_diff;
2523 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2524 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2525 		log.u_bbr.epoch = rack->r_ctl.rc_gp_srtt;
2526 		log.u_bbr.lt_epoch = rack->r_ctl.rc_prev_gp_srtt;
2527 		log.u_bbr.cwnd_gain = rack->rc_dragged_bottom;
2528 		log.u_bbr.cwnd_gain <<= 1;
2529 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_rec;
2530 		log.u_bbr.cwnd_gain <<= 1;
2531 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ss;
2532 		log.u_bbr.cwnd_gain <<= 1;
2533 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ca;
2534 		log.u_bbr.lost = rack->r_ctl.rc_loss_count;
2535 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2536 		    &rack->rc_inp->inp_socket->so_rcv,
2537 		    &rack->rc_inp->inp_socket->so_snd,
2538 		    TCP_TIMELY_WORK, 0,
2539 		    0, &log, false, &tv);
2540 	}
2541 }
2542 
2543 static int
2544 rack_bw_can_be_raised(struct tcp_rack *rack, uint64_t cur_bw, uint64_t last_bw_est, uint16_t mult)
2545 {
2546 	/*
2547 	 * Before we increase we need to know if
2548 	 * the estimate just made was less than
2549 	 * our pacing goal (i.e. (cur_bw * mult) > last_bw_est)
2550 	 *
2551 	 * If we already are pacing at a fast enough
2552 	 * rate to push us faster there is no sense of
2553 	 * increasing.
2554 	 *
2555 	 * We first caculate our actual pacing rate (ss or ca multipler
2556 	 * times our cur_bw).
2557 	 *
2558 	 * Then we take the last measured rate and multipy by our
2559 	 * maximum pacing overage to give us a max allowable rate.
2560 	 *
2561 	 * If our act_rate is smaller than our max_allowable rate
2562 	 * then we should increase. Else we should hold steady.
2563 	 *
2564 	 */
2565 	uint64_t act_rate, max_allow_rate;
2566 
2567 	if (rack_timely_no_stopping)
2568 		return (1);
2569 
2570 	if ((cur_bw == 0) || (last_bw_est == 0)) {
2571 		/*
2572 		 * Initial startup case or
2573 		 * everything is acked case.
2574 		 */
2575 		rack_log_timely(rack,  mult, cur_bw, 0, 0,
2576 				__LINE__, 9);
2577 		return (1);
2578 	}
2579 	if (mult <= 100) {
2580 		/*
2581 		 * We can always pace at or slightly above our rate.
2582 		 */
2583 		rack_log_timely(rack,  mult, cur_bw, 0, 0,
2584 				__LINE__, 9);
2585 		return (1);
2586 	}
2587 	act_rate = cur_bw * (uint64_t)mult;
2588 	act_rate /= 100;
2589 	max_allow_rate = last_bw_est * ((uint64_t)rack_max_per_above + (uint64_t)100);
2590 	max_allow_rate /= 100;
2591 	if (act_rate < max_allow_rate) {
2592 		/*
2593 		 * Here the rate we are actually pacing at
2594 		 * is smaller than 10% above our last measurement.
2595 		 * This means we are pacing below what we would
2596 		 * like to try to achieve (plus some wiggle room).
2597 		 */
2598 		rack_log_timely(rack,  mult, cur_bw, act_rate, max_allow_rate,
2599 				__LINE__, 9);
2600 		return (1);
2601 	} else {
2602 		/*
2603 		 * Here we are already pacing at least rack_max_per_above(10%)
2604 		 * what we are getting back. This indicates most likely
2605 		 * that we are being limited (cwnd/rwnd/app) and can't
2606 		 * get any more b/w. There is no sense of trying to
2607 		 * raise up the pacing rate its not speeding us up
2608 		 * and we already are pacing faster than we are getting.
2609 		 */
2610 		rack_log_timely(rack,  mult, cur_bw, act_rate, max_allow_rate,
2611 				__LINE__, 8);
2612 		return (0);
2613 	}
2614 }
2615 
2616 static void
2617 rack_validate_multipliers_at_or_above100(struct tcp_rack *rack)
2618 {
2619 	/*
2620 	 * When we drag bottom, we want to assure
2621 	 * that no multiplier is below 1.0, if so
2622 	 * we want to restore it to at least that.
2623 	 */
2624 	if (rack->r_ctl.rack_per_of_gp_rec  < 100) {
2625 		/* This is unlikely we usually do not touch recovery */
2626 		rack->r_ctl.rack_per_of_gp_rec = 100;
2627 	}
2628 	if (rack->r_ctl.rack_per_of_gp_ca < 100) {
2629 		rack->r_ctl.rack_per_of_gp_ca = 100;
2630 	}
2631 	if (rack->r_ctl.rack_per_of_gp_ss < 100) {
2632 		rack->r_ctl.rack_per_of_gp_ss = 100;
2633 	}
2634 }
2635 
2636 static void
2637 rack_validate_multipliers_at_or_below_100(struct tcp_rack *rack)
2638 {
2639 	if (rack->r_ctl.rack_per_of_gp_ca > 100) {
2640 		rack->r_ctl.rack_per_of_gp_ca = 100;
2641 	}
2642 	if (rack->r_ctl.rack_per_of_gp_ss > 100) {
2643 		rack->r_ctl.rack_per_of_gp_ss = 100;
2644 	}
2645 }
2646 
2647 static void
2648 rack_increase_bw_mul(struct tcp_rack *rack, int timely_says, uint64_t cur_bw, uint64_t last_bw_est, int override)
2649 {
2650 	int32_t  calc, logged, plus;
2651 
2652 	logged = 0;
2653 
2654 	if (override) {
2655 		/*
2656 		 * override is passed when we are
2657 		 * loosing b/w and making one last
2658 		 * gasp at trying to not loose out
2659 		 * to a new-reno flow.
2660 		 */
2661 		goto extra_boost;
2662 	}
2663 	/* In classic timely we boost by 5x if we have 5 increases in a row, lets not */
2664 	if (rack->rc_gp_incr &&
2665 	    ((rack->rc_gp_timely_inc_cnt + 1) >= RACK_TIMELY_CNT_BOOST)) {
2666 		/*
2667 		 * Reset and get 5 strokes more before the boost. Note
2668 		 * that the count is 0 based so we have to add one.
2669 		 */
2670 extra_boost:
2671 		plus = (uint32_t)rack_gp_increase_per * RACK_TIMELY_CNT_BOOST;
2672 		rack->rc_gp_timely_inc_cnt = 0;
2673 	} else
2674 		plus = (uint32_t)rack_gp_increase_per;
2675 	/* Must be at least 1% increase for true timely increases */
2676 	if ((plus < 1) &&
2677 	    ((rack->r_ctl.rc_rtt_diff <= 0) || (timely_says <= 0)))
2678 		plus = 1;
2679 	if (rack->rc_gp_saw_rec &&
2680 	    (rack->rc_gp_no_rec_chg == 0) &&
2681 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
2682 				  rack->r_ctl.rack_per_of_gp_rec)) {
2683 		/* We have been in recovery ding it too */
2684 		calc = rack->r_ctl.rack_per_of_gp_rec + plus;
2685 		if (calc > 0xffff)
2686 			calc = 0xffff;
2687 		logged |= 1;
2688 		rack->r_ctl.rack_per_of_gp_rec = (uint16_t)calc;
2689 		if (rack_per_upper_bound_ss &&
2690 		    (rack->rc_dragged_bottom == 0) &&
2691 		    (rack->r_ctl.rack_per_of_gp_rec > rack_per_upper_bound_ss))
2692 			rack->r_ctl.rack_per_of_gp_rec = rack_per_upper_bound_ss;
2693 	}
2694 	if (rack->rc_gp_saw_ca &&
2695 	    (rack->rc_gp_saw_ss == 0) &&
2696 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
2697 				  rack->r_ctl.rack_per_of_gp_ca)) {
2698 		/* In CA */
2699 		calc = rack->r_ctl.rack_per_of_gp_ca + plus;
2700 		if (calc > 0xffff)
2701 			calc = 0xffff;
2702 		logged |= 2;
2703 		rack->r_ctl.rack_per_of_gp_ca = (uint16_t)calc;
2704 		if (rack_per_upper_bound_ca &&
2705 		    (rack->rc_dragged_bottom == 0) &&
2706 		    (rack->r_ctl.rack_per_of_gp_ca > rack_per_upper_bound_ca))
2707 			rack->r_ctl.rack_per_of_gp_ca = rack_per_upper_bound_ca;
2708 	}
2709 	if (rack->rc_gp_saw_ss &&
2710 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
2711 				  rack->r_ctl.rack_per_of_gp_ss)) {
2712 		/* In SS */
2713 		calc = rack->r_ctl.rack_per_of_gp_ss + plus;
2714 		if (calc > 0xffff)
2715 			calc = 0xffff;
2716 		rack->r_ctl.rack_per_of_gp_ss = (uint16_t)calc;
2717 		if (rack_per_upper_bound_ss &&
2718 		    (rack->rc_dragged_bottom == 0) &&
2719 		    (rack->r_ctl.rack_per_of_gp_ss > rack_per_upper_bound_ss))
2720 			rack->r_ctl.rack_per_of_gp_ss = rack_per_upper_bound_ss;
2721 		logged |= 4;
2722 	}
2723 	if (logged &&
2724 	    (rack->rc_gp_incr == 0)){
2725 		/* Go into increment mode */
2726 		rack->rc_gp_incr = 1;
2727 		rack->rc_gp_timely_inc_cnt = 0;
2728 	}
2729 	if (rack->rc_gp_incr &&
2730 	    logged &&
2731 	    (rack->rc_gp_timely_inc_cnt < RACK_TIMELY_CNT_BOOST)) {
2732 		rack->rc_gp_timely_inc_cnt++;
2733 	}
2734 	rack_log_timely(rack,  logged, plus, 0, 0,
2735 			__LINE__, 1);
2736 }
2737 
2738 static uint32_t
2739 rack_get_decrease(struct tcp_rack *rack, uint32_t curper, int32_t rtt_diff)
2740 {
2741 	/*
2742 	 * norm_grad = rtt_diff / minrtt;
2743 	 * new_per = curper  * (1 - B * norm_grad)
2744 	 *
2745 	 * B = rack_gp_decrease_per (default 10%)
2746 	 * rtt_dif = input var current rtt-diff
2747 	 * curper = input var current percentage
2748 	 * minrtt = from rack filter
2749 	 *
2750 	 */
2751 	uint64_t perf;
2752 
2753 	perf = (((uint64_t)curper * ((uint64_t)1000000 -
2754 		    ((uint64_t)rack_gp_decrease_per * (uint64_t)10000 *
2755 		     (((uint64_t)rtt_diff * (uint64_t)1000000)/
2756 		      (uint64_t)get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt)))/
2757 		     (uint64_t)1000000)) /
2758 		(uint64_t)1000000);
2759 	if (perf > curper) {
2760 		/* TSNH */
2761 		perf = curper - 1;
2762 	}
2763 	return ((uint32_t)perf);
2764 }
2765 
2766 static uint32_t
2767 rack_decrease_highrtt(struct tcp_rack *rack, uint32_t curper, uint32_t rtt)
2768 {
2769 	/*
2770 	 *                                   highrttthresh
2771 	 * result = curper * (1 - (B * ( 1 -  ------          ))
2772 	 *                                     gp_srtt
2773 	 *
2774 	 * B = rack_gp_decrease_per (default 10%)
2775 	 * highrttthresh = filter_min * rack_gp_rtt_maxmul
2776 	 */
2777 	uint64_t perf;
2778 	uint32_t highrttthresh;
2779 
2780 	highrttthresh = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_maxmul;
2781 
2782 	perf =  (((uint64_t)curper * ((uint64_t)1000000 -
2783 				    ((uint64_t)rack_gp_decrease_per * ((uint64_t)1000000 -
2784 					((uint64_t)highrttthresh * (uint64_t)1000000) /
2785 						    (uint64_t)rtt)) / 100)) /(uint64_t)1000000);
2786 	return (perf);
2787 }
2788 
2789 
2790 static void
2791 rack_decrease_bw_mul(struct tcp_rack *rack, int timely_says, uint32_t rtt, int32_t rtt_diff)
2792 {
2793 	uint64_t logvar, logvar2, logvar3;
2794 	uint32_t logged, new_per, ss_red, ca_red, rec_red, alt, val;
2795 
2796 	if (rack->rc_gp_incr) {
2797 		/* Turn off increment counting  */
2798 		rack->rc_gp_incr = 0;
2799 		rack->rc_gp_timely_inc_cnt = 0;
2800 	}
2801 	ss_red = ca_red = rec_red = 0;
2802 	logged = 0;
2803 	/* Calculate the reduction value */
2804 	if (rtt_diff < 0) {
2805 		rtt_diff *= -1;
2806 	}
2807 	/* Must be at least 1% reduction */
2808 	if (rack->rc_gp_saw_rec && (rack->rc_gp_no_rec_chg == 0)) {
2809 		/* We have been in recovery ding it too */
2810 		if (timely_says == 2) {
2811 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_rec, rtt);
2812 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
2813 			if (alt < new_per)
2814 				val = alt;
2815 			else
2816 				val = new_per;
2817 		} else
2818 			 val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
2819 		if (rack->r_ctl.rack_per_of_gp_rec > val) {
2820 			rec_red = (rack->r_ctl.rack_per_of_gp_rec - val);
2821 			rack->r_ctl.rack_per_of_gp_rec = (uint16_t)val;
2822 		} else {
2823 			rack->r_ctl.rack_per_of_gp_rec = rack_per_lower_bound;
2824 			rec_red = 0;
2825 		}
2826 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_rec)
2827 			rack->r_ctl.rack_per_of_gp_rec = rack_per_lower_bound;
2828 		logged |= 1;
2829 	}
2830 	if (rack->rc_gp_saw_ss) {
2831 		/* Sent in SS */
2832 		if (timely_says == 2) {
2833 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_ss, rtt);
2834 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
2835 			if (alt < new_per)
2836 				val = alt;
2837 			else
2838 				val = new_per;
2839 		} else
2840 			val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_ss, rtt_diff);
2841 		if (rack->r_ctl.rack_per_of_gp_ss > new_per) {
2842 			ss_red = rack->r_ctl.rack_per_of_gp_ss - val;
2843 			rack->r_ctl.rack_per_of_gp_ss = (uint16_t)val;
2844 		} else {
2845 			ss_red = new_per;
2846 			rack->r_ctl.rack_per_of_gp_ss = rack_per_lower_bound;
2847 			logvar = new_per;
2848 			logvar <<= 32;
2849 			logvar |= alt;
2850 			logvar2 = (uint32_t)rtt;
2851 			logvar2 <<= 32;
2852 			logvar2 |= (uint32_t)rtt_diff;
2853 			logvar3 = rack_gp_rtt_maxmul;
2854 			logvar3 <<= 32;
2855 			logvar3 |= get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
2856 			rack_log_timely(rack, timely_says,
2857 					logvar2, logvar3,
2858 					logvar, __LINE__, 10);
2859 		}
2860 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_ss)
2861 			rack->r_ctl.rack_per_of_gp_ss = rack_per_lower_bound;
2862 		logged |= 4;
2863 	} else 	if (rack->rc_gp_saw_ca) {
2864 		/* Sent in CA */
2865 		if (timely_says == 2) {
2866 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_ca, rtt);
2867 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
2868 			if (alt < new_per)
2869 				val = alt;
2870 			else
2871 				val = new_per;
2872 		} else
2873 			val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_ca, rtt_diff);
2874 		if (rack->r_ctl.rack_per_of_gp_ca > val) {
2875 			ca_red = rack->r_ctl.rack_per_of_gp_ca - val;
2876 			rack->r_ctl.rack_per_of_gp_ca = (uint16_t)val;
2877 		} else {
2878 			rack->r_ctl.rack_per_of_gp_ca = rack_per_lower_bound;
2879 			ca_red = 0;
2880 			logvar = new_per;
2881 			logvar <<= 32;
2882 			logvar |= alt;
2883 			logvar2 = (uint32_t)rtt;
2884 			logvar2 <<= 32;
2885 			logvar2 |= (uint32_t)rtt_diff;
2886 			logvar3 = rack_gp_rtt_maxmul;
2887 			logvar3 <<= 32;
2888 			logvar3 |= get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
2889 			rack_log_timely(rack, timely_says,
2890 					logvar2, logvar3,
2891 					logvar, __LINE__, 10);
2892 		}
2893 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_ca)
2894 			rack->r_ctl.rack_per_of_gp_ca = rack_per_lower_bound;
2895 		logged |= 2;
2896 	}
2897 	if (rack->rc_gp_timely_dec_cnt < 0x7) {
2898 		rack->rc_gp_timely_dec_cnt++;
2899 		if (rack_timely_dec_clear &&
2900 		    (rack->rc_gp_timely_dec_cnt == rack_timely_dec_clear))
2901 			rack->rc_gp_timely_dec_cnt = 0;
2902 	}
2903 	logvar = ss_red;
2904 	logvar <<= 32;
2905 	logvar |= ca_red;
2906 	rack_log_timely(rack,  logged, rec_red, rack_per_lower_bound, logvar,
2907 			__LINE__, 2);
2908 }
2909 
2910 static void
2911 rack_log_rtt_shrinks(struct tcp_rack *rack, uint32_t us_cts,
2912 		     uint32_t rtt, uint32_t line, uint8_t reas)
2913 {
2914 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2915 		union tcp_log_stackspecific log;
2916 		struct timeval tv;
2917 
2918 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2919 		log.u_bbr.flex1 = line;
2920 		log.u_bbr.flex2 = rack->r_ctl.rc_time_probertt_starts;
2921 		log.u_bbr.flex3 = rack->r_ctl.rc_lower_rtt_us_cts;
2922 		log.u_bbr.flex4 = rack->r_ctl.rack_per_of_gp_ss;
2923 		log.u_bbr.flex5 = rtt;
2924 		log.u_bbr.flex6 = rack->rc_highly_buffered;
2925 		log.u_bbr.flex6 <<= 1;
2926 		log.u_bbr.flex6 |= rack->forced_ack;
2927 		log.u_bbr.flex6 <<= 1;
2928 		log.u_bbr.flex6 |= rack->rc_gp_dyn_mul;
2929 		log.u_bbr.flex6 <<= 1;
2930 		log.u_bbr.flex6 |= rack->in_probe_rtt;
2931 		log.u_bbr.flex6 <<= 1;
2932 		log.u_bbr.flex6 |= rack->measure_saw_probe_rtt;
2933 		log.u_bbr.flex7 = rack->r_ctl.rack_per_of_gp_probertt;
2934 		log.u_bbr.pacing_gain = rack->r_ctl.rack_per_of_gp_ca;
2935 		log.u_bbr.cwnd_gain = rack->r_ctl.rack_per_of_gp_rec;
2936 		log.u_bbr.flex8 = reas;
2937 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2938 		log.u_bbr.delRate = rack_get_bw(rack);
2939 		log.u_bbr.cur_del_rate = rack->r_ctl.rc_highest_us_rtt;
2940 		log.u_bbr.cur_del_rate <<= 32;
2941 		log.u_bbr.cur_del_rate |= rack->r_ctl.rc_lowest_us_rtt;
2942 		log.u_bbr.applimited = rack->r_ctl.rc_time_probertt_entered;
2943 		log.u_bbr.pkts_out = rack->r_ctl.rc_rtt_diff;
2944 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2945 		log.u_bbr.epoch = rack->r_ctl.rc_gp_srtt;
2946 		log.u_bbr.lt_epoch = rack->r_ctl.rc_prev_gp_srtt;
2947 		log.u_bbr.pkt_epoch = rack->r_ctl.rc_lower_rtt_us_cts;
2948 		log.u_bbr.delivered = rack->r_ctl.rc_target_probertt_flight;
2949 		log.u_bbr.lost = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
2950 		log.u_bbr.rttProp = us_cts;
2951 		log.u_bbr.rttProp <<= 32;
2952 		log.u_bbr.rttProp |= rack->r_ctl.rc_entry_gp_rtt;
2953 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2954 		    &rack->rc_inp->inp_socket->so_rcv,
2955 		    &rack->rc_inp->inp_socket->so_snd,
2956 		    BBR_LOG_RTT_SHRINKS, 0,
2957 		    0, &log, false, &rack->r_ctl.act_rcv_time);
2958 	}
2959 }
2960 
2961 static void
2962 rack_set_prtt_target(struct tcp_rack *rack, uint32_t segsiz, uint32_t rtt)
2963 {
2964 	uint64_t bwdp;
2965 
2966 	bwdp = rack_get_bw(rack);
2967 	bwdp *= (uint64_t)rtt;
2968 	bwdp /= (uint64_t)HPTS_USEC_IN_SEC;
2969 	rack->r_ctl.rc_target_probertt_flight = roundup((uint32_t)bwdp, segsiz);
2970 	if (rack->r_ctl.rc_target_probertt_flight < (segsiz * rack_timely_min_segs)) {
2971 		/*
2972 		 * A window protocol must be able to have 4 packets
2973 		 * outstanding as the floor in order to function
2974 		 * (especially considering delayed ack :D).
2975 		 */
2976 		rack->r_ctl.rc_target_probertt_flight = (segsiz * rack_timely_min_segs);
2977 	}
2978 }
2979 
2980 static void
2981 rack_enter_probertt(struct tcp_rack *rack, uint32_t us_cts)
2982 {
2983 	/**
2984 	 * ProbeRTT is a bit different in rack_pacing than in
2985 	 * BBR. It is like BBR in that it uses the lowering of
2986 	 * the RTT as a signal that we saw something new and
2987 	 * counts from there for how long between. But it is
2988 	 * different in that its quite simple. It does not
2989 	 * play with the cwnd and wait until we get down
2990 	 * to N segments outstanding and hold that for
2991 	 * 200ms. Instead it just sets the pacing reduction
2992 	 * rate to a set percentage (70 by default) and hold
2993 	 * that for a number of recent GP Srtt's.
2994 	 */
2995 	uint32_t segsiz;
2996 
2997 	if (rack->rc_gp_dyn_mul == 0)
2998 		return;
2999 
3000 	if (rack->rc_tp->snd_max == rack->rc_tp->snd_una) {
3001 		/* We are idle */
3002 		return;
3003 	}
3004 	if ((rack->rc_tp->t_flags & TF_GPUTINPROG) &&
3005 	    SEQ_GT(rack->rc_tp->snd_una, rack->rc_tp->gput_seq)) {
3006 		/*
3007 		 * Stop the goodput now, the idea here is
3008 		 * that future measurements with in_probe_rtt
3009 		 * won't register if they are not greater so
3010 		 * we want to get what info (if any) is available
3011 		 * now.
3012 		 */
3013 		rack_do_goodput_measurement(rack->rc_tp, rack,
3014 					    rack->rc_tp->snd_una, __LINE__);
3015 	}
3016 	rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
3017 	rack->r_ctl.rc_time_probertt_entered = us_cts;
3018 	segsiz = min(ctf_fixed_maxseg(rack->rc_tp),
3019 		     rack->r_ctl.rc_pace_min_segs);
3020 	rack->in_probe_rtt = 1;
3021 	rack->measure_saw_probe_rtt = 1;
3022 	rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
3023 	rack->r_ctl.rc_time_probertt_starts = 0;
3024 	rack->r_ctl.rc_entry_gp_rtt = rack->r_ctl.rc_gp_srtt;
3025 	if (rack_probertt_use_min_rtt_entry)
3026 		rack_set_prtt_target(rack, segsiz, get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt));
3027 	else
3028 		rack_set_prtt_target(rack, segsiz, rack->r_ctl.rc_gp_srtt);
3029 	rack_log_rtt_shrinks(rack,  us_cts,  get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3030 			     __LINE__, RACK_RTTS_ENTERPROBE);
3031 }
3032 
3033 static void
3034 rack_exit_probertt(struct tcp_rack *rack, uint32_t us_cts)
3035 {
3036 	struct rack_sendmap *rsm;
3037 	uint32_t segsiz;
3038 
3039 	segsiz = min(ctf_fixed_maxseg(rack->rc_tp),
3040 		     rack->r_ctl.rc_pace_min_segs);
3041 	rack->in_probe_rtt = 0;
3042 	if ((rack->rc_tp->t_flags & TF_GPUTINPROG) &&
3043 	    SEQ_GT(rack->rc_tp->snd_una, rack->rc_tp->gput_seq)) {
3044 		/*
3045 		 * Stop the goodput now, the idea here is
3046 		 * that future measurements with in_probe_rtt
3047 		 * won't register if they are not greater so
3048 		 * we want to get what info (if any) is available
3049 		 * now.
3050 		 */
3051 		rack_do_goodput_measurement(rack->rc_tp, rack,
3052 					    rack->rc_tp->snd_una, __LINE__);
3053 	} else if (rack->rc_tp->t_flags & TF_GPUTINPROG) {
3054 		/*
3055 		 * We don't have enough data to make a measurement.
3056 		 * So lets just stop and start here after exiting
3057 		 * probe-rtt. We probably are not interested in
3058 		 * the results anyway.
3059 		 */
3060 		rack->rc_tp->t_flags &= ~TF_GPUTINPROG;
3061 	}
3062 	/*
3063 	 * Measurements through the current snd_max are going
3064 	 * to be limited by the slower pacing rate.
3065 	 *
3066 	 * We need to mark these as app-limited so we
3067 	 * don't collapse the b/w.
3068 	 */
3069 	rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
3070 	if (rsm && ((rsm->r_flags & RACK_APP_LIMITED) == 0)) {
3071 		if (rack->r_ctl.rc_app_limited_cnt == 0)
3072 			rack->r_ctl.rc_end_appl = rack->r_ctl.rc_first_appl = rsm;
3073 		else {
3074 			/*
3075 			 * Go out to the end app limited and mark
3076 			 * this new one as next and move the end_appl up
3077 			 * to this guy.
3078 			 */
3079 			if (rack->r_ctl.rc_end_appl)
3080 				rack->r_ctl.rc_end_appl->r_nseq_appl = rsm->r_start;
3081 			rack->r_ctl.rc_end_appl = rsm;
3082 		}
3083 		rsm->r_flags |= RACK_APP_LIMITED;
3084 		rack->r_ctl.rc_app_limited_cnt++;
3085 	}
3086 	/*
3087 	 * Now, we need to examine our pacing rate multipliers.
3088 	 * If its under 100%, we need to kick it back up to
3089 	 * 100%. We also don't let it be over our "max" above
3090 	 * the actual rate i.e. 100% + rack_clamp_atexit_prtt.
3091 	 * Note setting clamp_atexit_prtt to 0 has the effect
3092 	 * of setting CA/SS to 100% always at exit (which is
3093 	 * the default behavior).
3094 	 */
3095 	if (rack_probertt_clear_is) {
3096 		rack->rc_gp_incr = 0;
3097 		rack->rc_gp_bwred = 0;
3098 		rack->rc_gp_timely_inc_cnt = 0;
3099 		rack->rc_gp_timely_dec_cnt = 0;
3100 	}
3101 	/* Do we do any clamping at exit? */
3102 	if (rack->rc_highly_buffered && rack_atexit_prtt_hbp) {
3103 		rack->r_ctl.rack_per_of_gp_ca = rack_atexit_prtt_hbp;
3104 		rack->r_ctl.rack_per_of_gp_ss = rack_atexit_prtt_hbp;
3105 	}
3106 	if ((rack->rc_highly_buffered == 0) && rack_atexit_prtt) {
3107 		rack->r_ctl.rack_per_of_gp_ca = rack_atexit_prtt;
3108 		rack->r_ctl.rack_per_of_gp_ss = rack_atexit_prtt;
3109 	}
3110 	/*
3111 	 * Lets set rtt_diff to 0, so that we will get a "boost"
3112 	 * after exiting.
3113 	 */
3114 	rack->r_ctl.rc_rtt_diff = 0;
3115 
3116 	/* Clear all flags so we start fresh */
3117 	rack->rc_tp->t_bytes_acked = 0;
3118 	rack->rc_tp->ccv->flags &= ~CCF_ABC_SENTAWND;
3119 	/*
3120 	 * If configured to, set the cwnd and ssthresh to
3121 	 * our targets.
3122 	 */
3123 	if (rack_probe_rtt_sets_cwnd) {
3124 		uint64_t ebdp;
3125 		uint32_t setto;
3126 
3127 		/* Set ssthresh so we get into CA once we hit our target */
3128 		if (rack_probertt_use_min_rtt_exit == 1) {
3129 			/* Set to min rtt */
3130 			rack_set_prtt_target(rack, segsiz,
3131 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt));
3132 		} else if (rack_probertt_use_min_rtt_exit == 2) {
3133 			/* Set to current gp rtt */
3134 			rack_set_prtt_target(rack, segsiz,
3135 					     rack->r_ctl.rc_gp_srtt);
3136 		} else if (rack_probertt_use_min_rtt_exit == 3) {
3137 			/* Set to entry gp rtt */
3138 			rack_set_prtt_target(rack, segsiz,
3139 					     rack->r_ctl.rc_entry_gp_rtt);
3140 		} else  {
3141 			uint64_t sum;
3142 			uint32_t setval;
3143 
3144 			sum = rack->r_ctl.rc_entry_gp_rtt;
3145 			sum *= 10;
3146 			sum /= (uint64_t)(max(1, rack->r_ctl.rc_gp_srtt));
3147 			if (sum >= 20) {
3148 				/*
3149 				 * A highly buffered path needs
3150 				 * cwnd space for timely to work.
3151 				 * Lets set things up as if
3152 				 * we are heading back here again.
3153 				 */
3154 				setval = rack->r_ctl.rc_entry_gp_rtt;
3155 			} else if (sum >= 15) {
3156 				/*
3157 				 * Lets take the smaller of the
3158 				 * two since we are just somewhat
3159 				 * buffered.
3160 				 */
3161 				setval = rack->r_ctl.rc_gp_srtt;
3162 				if (setval > rack->r_ctl.rc_entry_gp_rtt)
3163 					setval = rack->r_ctl.rc_entry_gp_rtt;
3164 			} else {
3165 				/*
3166 				 * Here we are not highly buffered
3167 				 * and should pick the min we can to
3168 				 * keep from causing loss.
3169 				 */
3170 				setval = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
3171 			}
3172 			rack_set_prtt_target(rack, segsiz,
3173 					     setval);
3174 		}
3175 		if (rack_probe_rtt_sets_cwnd > 1) {
3176 			/* There is a percentage here to boost */
3177 			ebdp = rack->r_ctl.rc_target_probertt_flight;
3178 			ebdp *= rack_probe_rtt_sets_cwnd;
3179 			ebdp /= 100;
3180 			setto = rack->r_ctl.rc_target_probertt_flight + ebdp;
3181 		} else
3182 			setto = rack->r_ctl.rc_target_probertt_flight;
3183 		rack->rc_tp->snd_cwnd = roundup(setto, segsiz);
3184 		if (rack->rc_tp->snd_cwnd < (segsiz * rack_timely_min_segs)) {
3185 			/* Enforce a min */
3186 			rack->rc_tp->snd_cwnd = segsiz * rack_timely_min_segs;
3187 		}
3188 		/* If we set in the cwnd also set the ssthresh point so we are in CA */
3189 		rack->rc_tp->snd_ssthresh = (rack->rc_tp->snd_cwnd - 1);
3190 	}
3191 	rack_log_rtt_shrinks(rack,  us_cts,
3192 			     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3193 			     __LINE__, RACK_RTTS_EXITPROBE);
3194 	/* Clear times last so log has all the info */
3195 	rack->r_ctl.rc_probertt_sndmax_atexit = rack->rc_tp->snd_max;
3196 	rack->r_ctl.rc_time_probertt_entered = us_cts;
3197 	rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
3198 	rack->r_ctl.rc_time_of_last_probertt = us_cts;
3199 }
3200 
3201 static void
3202 rack_check_probe_rtt(struct tcp_rack *rack, uint32_t us_cts)
3203 {
3204 	/* Check in on probe-rtt */
3205 	if (rack->rc_gp_filled == 0) {
3206 		/* We do not do p-rtt unless we have gp measurements */
3207 		return;
3208 	}
3209 	if (rack->in_probe_rtt) {
3210 		uint64_t no_overflow;
3211 		uint32_t endtime, must_stay;
3212 
3213 		if (rack->r_ctl.rc_went_idle_time &&
3214 		    ((us_cts - rack->r_ctl.rc_went_idle_time) > rack_min_probertt_hold)) {
3215 			/*
3216 			 * We went idle during prtt, just exit now.
3217 			 */
3218 			rack_exit_probertt(rack, us_cts);
3219 		} else if (rack_probe_rtt_safety_val &&
3220 		    TSTMP_GT(us_cts, rack->r_ctl.rc_time_probertt_entered) &&
3221 		    ((us_cts - rack->r_ctl.rc_time_probertt_entered) > rack_probe_rtt_safety_val)) {
3222 			/*
3223 			 * Probe RTT safety value triggered!
3224 			 */
3225 			rack_log_rtt_shrinks(rack,  us_cts,
3226 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3227 					     __LINE__, RACK_RTTS_SAFETY);
3228 			rack_exit_probertt(rack, us_cts);
3229 		}
3230 		/* Calculate the max we will wait */
3231 		endtime = rack->r_ctl.rc_time_probertt_entered + (rack->r_ctl.rc_gp_srtt * rack_max_drain_wait);
3232 		if (rack->rc_highly_buffered)
3233 			endtime += (rack->r_ctl.rc_gp_srtt * rack_max_drain_hbp);
3234 		/* Calculate the min we must wait */
3235 		must_stay = rack->r_ctl.rc_time_probertt_entered + (rack->r_ctl.rc_gp_srtt * rack_must_drain);
3236 		if ((ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) > rack->r_ctl.rc_target_probertt_flight) &&
3237 		    TSTMP_LT(us_cts, endtime)) {
3238 			uint32_t calc;
3239 			/* Do we lower more? */
3240 no_exit:
3241 			if (TSTMP_GT(us_cts, rack->r_ctl.rc_time_probertt_entered))
3242 				calc = us_cts - rack->r_ctl.rc_time_probertt_entered;
3243 			else
3244 				calc = 0;
3245 			calc /= max(rack->r_ctl.rc_gp_srtt, 1);
3246 			if (calc) {
3247 				/* Maybe */
3248 				calc *= rack_per_of_gp_probertt_reduce;
3249 				rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt - calc;
3250 				/* Limit it too */
3251 				if (rack->r_ctl.rack_per_of_gp_probertt < rack_per_of_gp_lowthresh)
3252 					rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_lowthresh;
3253 			}
3254 			/* We must reach target or the time set */
3255 			return;
3256 		}
3257 		if (rack->r_ctl.rc_time_probertt_starts == 0) {
3258 			if ((TSTMP_LT(us_cts, must_stay) &&
3259 			     rack->rc_highly_buffered) ||
3260 			     (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) >
3261 			      rack->r_ctl.rc_target_probertt_flight)) {
3262 				/* We are not past the must_stay time */
3263 				goto no_exit;
3264 			}
3265 			rack_log_rtt_shrinks(rack,  us_cts,
3266 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3267 					     __LINE__, RACK_RTTS_REACHTARGET);
3268 			rack->r_ctl.rc_time_probertt_starts = us_cts;
3269 			if (rack->r_ctl.rc_time_probertt_starts == 0)
3270 				rack->r_ctl.rc_time_probertt_starts = 1;
3271 			/* Restore back to our rate we want to pace at in prtt */
3272 			rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
3273 		}
3274 		/*
3275 		 * Setup our end time, some number of gp_srtts plus 200ms.
3276 		 */
3277 		no_overflow = ((uint64_t)rack->r_ctl.rc_gp_srtt *
3278 			       (uint64_t)rack_probertt_gpsrtt_cnt_mul);
3279 		if (rack_probertt_gpsrtt_cnt_div)
3280 			endtime = (uint32_t)(no_overflow / (uint64_t)rack_probertt_gpsrtt_cnt_div);
3281 		else
3282 			endtime = 0;
3283 		endtime += rack_min_probertt_hold;
3284 		endtime += rack->r_ctl.rc_time_probertt_starts;
3285 		if (TSTMP_GEQ(us_cts,  endtime)) {
3286 			/* yes, exit probertt  */
3287 			rack_exit_probertt(rack, us_cts);
3288  		}
3289 
3290 	} else 	if((us_cts - rack->r_ctl.rc_lower_rtt_us_cts) >= rack_time_between_probertt) {
3291 		/* Go into probertt, its been too long since we went lower  */
3292 		rack_enter_probertt(rack, us_cts);
3293 	}
3294 }
3295 
3296 static void
3297 rack_update_multiplier(struct tcp_rack *rack, int32_t timely_says, uint64_t last_bw_est,
3298 		       uint32_t rtt, int32_t rtt_diff)
3299 {
3300 	uint64_t cur_bw, up_bnd, low_bnd, subfr;
3301 	uint32_t losses;
3302 
3303 	if ((rack->rc_gp_dyn_mul == 0) ||
3304 	    (rack->use_fixed_rate) ||
3305 	    (rack->in_probe_rtt) ||
3306 	    (rack->rc_always_pace == 0)) {
3307 		/* No dynamic GP multipler in play */
3308 		return;
3309 	}
3310 	losses = rack->r_ctl.rc_loss_count - rack->r_ctl.rc_loss_at_start;
3311 	cur_bw = rack_get_bw(rack);
3312 	/* Calculate our up and down range */
3313 	up_bnd = rack->r_ctl.last_gp_comp_bw * (uint64_t)rack_gp_per_bw_mul_up;
3314 	up_bnd /= 100;
3315 	up_bnd += rack->r_ctl.last_gp_comp_bw;
3316 
3317 	subfr = (uint64_t)rack->r_ctl.last_gp_comp_bw * (uint64_t)rack_gp_per_bw_mul_down;
3318 	subfr /= 100;
3319 	low_bnd = rack->r_ctl.last_gp_comp_bw - subfr;
3320 	if ((timely_says == 2) && (rack->r_ctl.rc_no_push_at_mrtt)) {
3321 		/*
3322 		 * This is the case where our RTT is above
3323 		 * the max target and we have been configured
3324 		 * to just do timely no bonus up stuff in that case.
3325 		 *
3326 		 * There are two configurations, set to 1, and we
3327 		 * just do timely if we are over our max. If its
3328 		 * set above 1 then we slam the multipliers down
3329 		 * to 100 and then decrement per timely.
3330 		 */
3331 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3332 				__LINE__, 3);
3333 		if (rack->r_ctl.rc_no_push_at_mrtt > 1)
3334 			rack_validate_multipliers_at_or_below_100(rack);
3335 		rack_decrease_bw_mul(rack, timely_says, rtt, rtt_diff);
3336 	} else if ((last_bw_est < low_bnd) && !losses) {
3337 		/*
3338 		 * We are decreasing this is a bit complicated this
3339 		 * means we are loosing ground. This could be
3340 		 * because another flow entered and we are competing
3341 		 * for b/w with it. This will push the RTT up which
3342 		 * makes timely unusable unless we want to get shoved
3343 		 * into a corner and just be backed off (the age
3344 		 * old problem with delay based CC).
3345 		 *
3346 		 * On the other hand if it was a route change we
3347 		 * would like to stay somewhat contained and not
3348 		 * blow out the buffers.
3349 		 */
3350 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3351 				__LINE__, 3);
3352 		rack->r_ctl.last_gp_comp_bw = cur_bw;
3353 		if (rack->rc_gp_bwred == 0) {
3354 			/* Go into reduction counting */
3355 			rack->rc_gp_bwred = 1;
3356 			rack->rc_gp_timely_dec_cnt = 0;
3357 		}
3358 		if ((rack->rc_gp_timely_dec_cnt < rack_timely_max_push_drop) ||
3359 		    (timely_says == 0)) {
3360 			/*
3361 			 * Push another time with a faster pacing
3362 			 * to try to gain back (we include override to
3363 			 * get a full raise factor).
3364 			 */
3365 			if ((rack->rc_gp_saw_ca && rack->r_ctl.rack_per_of_gp_ca <= rack_down_raise_thresh) ||
3366 			    (rack->rc_gp_saw_ss && rack->r_ctl.rack_per_of_gp_ss <= rack_down_raise_thresh) ||
3367 			    (timely_says == 0) ||
3368 			    (rack_down_raise_thresh == 0)) {
3369 				/*
3370 				 * Do an override up in b/w if we were
3371 				 * below the threshold or if the threshold
3372 				 * is zero we always do the raise.
3373 				 */
3374 				rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 1);
3375 			} else {
3376 				/* Log it stays the same */
3377 				rack_log_timely(rack,  0, last_bw_est, low_bnd, 0,
3378 						__LINE__, 11);
3379 
3380 			}
3381 			rack->rc_gp_timely_dec_cnt++;
3382 			/* We are not incrementing really no-count */
3383 			rack->rc_gp_incr = 0;
3384 			rack->rc_gp_timely_inc_cnt = 0;
3385 		} else {
3386 			/*
3387 			 * Lets just use the RTT
3388 			 * information and give up
3389 			 * pushing.
3390 			 */
3391 			goto use_timely;
3392 		}
3393 	}  else if ((timely_says != 2) &&
3394 		    !losses &&
3395 		    (last_bw_est > up_bnd)) {
3396 		/*
3397 		 * We are increasing b/w lets keep going, updating
3398 		 * our b/w and ignoring any timely input, unless
3399 		 * of course we are at our max raise (if there is one).
3400 		 */
3401 
3402 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3403 				__LINE__, 3);
3404 		rack->r_ctl.last_gp_comp_bw = cur_bw;
3405 		if (rack->rc_gp_saw_ss &&
3406 		    rack_per_upper_bound_ss &&
3407 		     (rack->r_ctl.rack_per_of_gp_ss == rack_per_upper_bound_ss)) {
3408 			    /*
3409 			     * In cases where we can't go higher
3410 			     * we should just use timely.
3411 			     */
3412 			    goto use_timely;
3413 		}
3414 		if (rack->rc_gp_saw_ca &&
3415 		    rack_per_upper_bound_ca &&
3416 		    (rack->r_ctl.rack_per_of_gp_ca == rack_per_upper_bound_ca)) {
3417 			    /*
3418 			     * In cases where we can't go higher
3419 			     * we should just use timely.
3420 			     */
3421 			    goto use_timely;
3422 		}
3423 		rack->rc_gp_bwred = 0;
3424 		rack->rc_gp_timely_dec_cnt = 0;
3425 		/* You get a set number of pushes if timely is trying to reduce  */
3426 		if ((rack->rc_gp_incr < rack_timely_max_push_rise) || (timely_says == 0)) {
3427 			rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
3428 		} else {
3429  			/* Log it stays the same */
3430 			rack_log_timely(rack,  0, last_bw_est, up_bnd, 0,
3431 			    __LINE__, 12);
3432 
3433 		}
3434 		return;
3435 	} else {
3436 		/*
3437 		 * We are staying between the lower and upper range bounds
3438 		 * so use timely to decide.
3439 		 */
3440 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3441 				__LINE__, 3);
3442 use_timely:
3443 		if (timely_says) {
3444 			rack->rc_gp_incr = 0;
3445 			rack->rc_gp_timely_inc_cnt = 0;
3446 			if ((rack->rc_gp_timely_dec_cnt < rack_timely_max_push_drop) &&
3447 			    !losses &&
3448 			    (last_bw_est < low_bnd)) {
3449 				/* We are loosing ground */
3450 				rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
3451 				rack->rc_gp_timely_dec_cnt++;
3452 				/* We are not incrementing really no-count */
3453 				rack->rc_gp_incr = 0;
3454 				rack->rc_gp_timely_inc_cnt = 0;
3455 			} else
3456 				rack_decrease_bw_mul(rack, timely_says, rtt, rtt_diff);
3457 		} else  {
3458 			rack->rc_gp_bwred = 0;
3459 			rack->rc_gp_timely_dec_cnt = 0;
3460 			rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
3461 		}
3462 	}
3463 }
3464 
3465 static int32_t
3466 rack_make_timely_judgement(struct tcp_rack *rack, uint32_t rtt, int32_t rtt_diff, uint32_t prev_rtt)
3467 {
3468 	int32_t timely_says;
3469 	uint64_t log_mult, log_rtt_a_diff;
3470 
3471 	log_rtt_a_diff = rtt;
3472 	log_rtt_a_diff <<= 32;
3473 	log_rtt_a_diff |= (uint32_t)rtt_diff;
3474 	if (rtt >= (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) *
3475 		    rack_gp_rtt_maxmul)) {
3476 		/* Reduce the b/w multipler */
3477 		timely_says = 2;
3478 		log_mult = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_maxmul;
3479 		log_mult <<= 32;
3480 		log_mult |= prev_rtt;
3481 		rack_log_timely(rack,  timely_says, log_mult,
3482 				get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3483 				log_rtt_a_diff, __LINE__, 4);
3484 	} else if (rtt <= (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) +
3485 			   ((get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_minmul) /
3486 			    max(rack_gp_rtt_mindiv , 1)))) {
3487 		/* Increase the b/w multipler */
3488 		log_mult = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) +
3489 			((get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_minmul) /
3490 			 max(rack_gp_rtt_mindiv , 1));
3491 		log_mult <<= 32;
3492 		log_mult |= prev_rtt;
3493 		timely_says = 0;
3494 		rack_log_timely(rack,  timely_says, log_mult ,
3495 				get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3496 				log_rtt_a_diff, __LINE__, 5);
3497 	} else {
3498 		/*
3499 		 * Use a gradient to find it the timely gradient
3500 		 * is:
3501 		 * grad = rc_rtt_diff / min_rtt;
3502 		 *
3503 		 * anything below or equal to 0 will be
3504 		 * a increase indication. Anything above
3505 		 * zero is a decrease. Note we take care
3506 		 * of the actual gradient calculation
3507 		 * in the reduction (its not needed for
3508 		 * increase).
3509 		 */
3510 		log_mult = prev_rtt;
3511 		if (rtt_diff <= 0) {
3512 			/*
3513 			 * Rttdiff is less than zero, increase the
3514 			 * b/w multipler (its 0 or negative)
3515 			 */
3516 			timely_says = 0;
3517 			rack_log_timely(rack,  timely_says, log_mult,
3518 					get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt), log_rtt_a_diff, __LINE__, 6);
3519 		} else {
3520 			/* Reduce the b/w multipler */
3521 			timely_says = 1;
3522 			rack_log_timely(rack,  timely_says, log_mult,
3523 					get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt), log_rtt_a_diff, __LINE__, 7);
3524 		}
3525 	}
3526 	return (timely_says);
3527 }
3528 
3529 static void
3530 rack_do_goodput_measurement(struct tcpcb *tp, struct tcp_rack *rack,
3531 			    tcp_seq th_ack, int line)
3532 {
3533 	uint64_t tim, bytes_ps, ltim, stim, utim;
3534 	uint32_t segsiz, bytes, reqbytes, us_cts;
3535 	int32_t gput, new_rtt_diff, timely_says;
3536 
3537 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
3538 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
3539 	if (TSTMP_GEQ(us_cts, tp->gput_ts))
3540 		tim = us_cts - tp->gput_ts;
3541 	else
3542 		tim = 0;
3543 
3544 	if (TSTMP_GT(rack->r_ctl.rc_gp_cumack_ts, rack->r_ctl.rc_gp_output_ts))
3545 		stim = rack->r_ctl.rc_gp_cumack_ts - rack->r_ctl.rc_gp_output_ts;
3546 	else
3547 		stim = 0;
3548 	/*
3549 	 * Use the larger of the send time or ack time. This prevents us
3550 	 * from being influenced by ack artifacts to come up with too
3551 	 * high of measurement. Note that since we are spanning over many more
3552 	 * bytes in most of our measurements hopefully that is less likely to
3553 	 * occur.
3554 	 */
3555 	if (tim > stim)
3556 		utim = max(tim, 1);
3557 	else
3558 		utim = max(stim, 1);
3559 	/* Lets validate utim */
3560 	ltim = max(1, (utim/HPTS_USEC_IN_MSEC));
3561 	gput = (((uint64_t) (th_ack - tp->gput_seq)) << 3) / ltim;
3562 	reqbytes = min(rc_init_window(rack), (MIN_GP_WIN * segsiz));
3563 	if ((tim == 0) && (stim == 0)) {
3564 		/*
3565 		 * Invalid measurement time, maybe
3566 		 * all on one ack/one send?
3567 		 */
3568 		bytes = 0;
3569 		bytes_ps = 0;
3570 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
3571 					   0, 0, 0, 10, __LINE__, NULL);
3572 		goto skip_measurement;
3573 	}
3574 	if (rack->r_ctl.rc_gp_lowrtt == 0xffffffff) {
3575 		/* We never made a us_rtt measurement? */
3576 		bytes = 0;
3577 		bytes_ps = 0;
3578 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
3579 					   0, 0, 0, 10, __LINE__, NULL);
3580 		goto skip_measurement;
3581 	}
3582 	/*
3583 	 * Calculate the maximum possible b/w this connection
3584 	 * could have. We base our calculation on the lowest
3585 	 * rtt we have seen during the measurement and the
3586 	 * largest rwnd the client has given us in that time. This
3587 	 * forms a BDP that is the maximum that we could ever
3588 	 * get to the client. Anything larger is not valid.
3589 	 *
3590 	 * I originally had code here that rejected measurements
3591 	 * where the time was less than 1/2 the latest us_rtt.
3592 	 * But after thinking on that I realized its wrong since
3593 	 * say you had a 150Mbps or even 1Gbps link, and you
3594 	 * were a long way away.. example I am in Europe (100ms rtt)
3595 	 * talking to my 1Gbps link in S.C. Now measuring say 150,000
3596 	 * bytes my time would be 1.2ms, and yet my rtt would say
3597 	 * the measurement was invalid the time was < 50ms. The
3598 	 * same thing is true for 150Mb (8ms of time).
3599 	 *
3600 	 * A better way I realized is to look at what the maximum
3601 	 * the connection could possibly do. This is gated on
3602 	 * the lowest RTT we have seen and the highest rwnd.
3603 	 * We should in theory never exceed that, if we are
3604 	 * then something on the path is storing up packets
3605 	 * and then feeding them all at once to our endpoint
3606 	 * messing up our measurement.
3607 	 */
3608 	rack->r_ctl.last_max_bw = rack->r_ctl.rc_gp_high_rwnd;
3609 	rack->r_ctl.last_max_bw *= HPTS_USEC_IN_SEC;
3610 	rack->r_ctl.last_max_bw /= rack->r_ctl.rc_gp_lowrtt;
3611 	if (SEQ_LT(th_ack, tp->gput_seq)) {
3612 		/* No measurement can be made */
3613 		bytes = 0;
3614 		bytes_ps = 0;
3615 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
3616 					   0, 0, 0, 10, __LINE__, NULL);
3617 		goto skip_measurement;
3618 	} else
3619 		bytes = (th_ack - tp->gput_seq);
3620 	bytes_ps = (uint64_t)bytes;
3621 	/*
3622 	 * Don't measure a b/w for pacing unless we have gotten at least
3623 	 * an initial windows worth of data in this measurement interval.
3624 	 *
3625 	 * Small numbers of bytes get badly influenced by delayed ack and
3626 	 * other artifacts. Note we take the initial window or our
3627 	 * defined minimum GP (defaulting to 10 which hopefully is the
3628 	 * IW).
3629 	 */
3630 	if (rack->rc_gp_filled == 0) {
3631 		/*
3632 		 * The initial estimate is special. We
3633 		 * have blasted out an IW worth of packets
3634 		 * without a real valid ack ts results. We
3635 		 * then setup the app_limited_needs_set flag,
3636 		 * this should get the first ack in (probably 2
3637 		 * MSS worth) to be recorded as the timestamp.
3638 		 * We thus allow a smaller number of bytes i.e.
3639 		 * IW - 2MSS.
3640 		 */
3641 		reqbytes -= (2 * segsiz);
3642 		/* Also lets fill previous for our first measurement to be neutral */
3643 		rack->r_ctl.rc_prev_gp_srtt = rack->r_ctl.rc_gp_srtt;
3644 	}
3645 	if ((bytes_ps < reqbytes) || rack->app_limited_needs_set) {
3646 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
3647 					   rack->r_ctl.rc_app_limited_cnt,
3648 					   0, 0, 10, __LINE__, NULL);
3649 		goto skip_measurement;
3650 	}
3651 	/*
3652 	 * We now need to calculate the Timely like status so
3653 	 * we can update (possibly) the b/w multipliers.
3654 	 */
3655 	new_rtt_diff = (int32_t)rack->r_ctl.rc_gp_srtt - (int32_t)rack->r_ctl.rc_prev_gp_srtt;
3656 	if (rack->rc_gp_filled == 0) {
3657 		/* No previous reading */
3658 		rack->r_ctl.rc_rtt_diff = new_rtt_diff;
3659 	} else {
3660 		if (rack->measure_saw_probe_rtt == 0) {
3661 			/*
3662 			 * We don't want a probertt to be counted
3663 			 * since it will be negative incorrectly. We
3664 			 * expect to be reducing the RTT when we
3665 			 * pace at a slower rate.
3666 			 */
3667 			rack->r_ctl.rc_rtt_diff -= (rack->r_ctl.rc_rtt_diff / 8);
3668 			rack->r_ctl.rc_rtt_diff += (new_rtt_diff / 8);
3669 		}
3670 	}
3671 	timely_says = rack_make_timely_judgement(rack,
3672 		rack->r_ctl.rc_gp_srtt,
3673 		rack->r_ctl.rc_rtt_diff,
3674 	        rack->r_ctl.rc_prev_gp_srtt
3675 		);
3676 	bytes_ps *= HPTS_USEC_IN_SEC;
3677 	bytes_ps /= utim;
3678 	if (bytes_ps > rack->r_ctl.last_max_bw) {
3679 		/*
3680 		 * Something is on path playing
3681 		 * since this b/w is not possible based
3682 		 * on our BDP (highest rwnd and lowest rtt
3683 		 * we saw in the measurement window).
3684 		 *
3685 		 * Another option here would be to
3686 		 * instead skip the measurement.
3687 		 */
3688 		rack_log_pacing_delay_calc(rack, bytes, reqbytes,
3689 					   bytes_ps, rack->r_ctl.last_max_bw, 0,
3690 					   11, __LINE__, NULL);
3691 		bytes_ps = rack->r_ctl.last_max_bw;
3692 	}
3693 	/* We store gp for b/w in bytes per second  */
3694 	if (rack->rc_gp_filled == 0) {
3695 		/* Initial measurment */
3696 		if (bytes_ps) {
3697 			rack->r_ctl.gp_bw = bytes_ps;
3698 			rack->rc_gp_filled = 1;
3699 			rack->r_ctl.num_avg = 1;
3700 			rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
3701 		} else {
3702 			rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
3703 						   rack->r_ctl.rc_app_limited_cnt,
3704 						   0, 0, 10, __LINE__, NULL);
3705 		}
3706 		if (rack->rc_inp->inp_in_hpts &&
3707 		    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
3708 			/*
3709 			 * Ok we can't trust the pacer in this case
3710 			 * where we transition from un-paced to paced.
3711 			 * Or for that matter when the burst mitigation
3712 			 * was making a wild guess and got it wrong.
3713 			 * Stop the pacer and clear up all the aggregate
3714 			 * delays etc.
3715 			 */
3716 			tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
3717 			rack->r_ctl.rc_hpts_flags = 0;
3718 			rack->r_ctl.rc_last_output_to = 0;
3719 		}
3720 	} else if (rack->r_ctl.num_avg < RACK_REQ_AVG) {
3721 		/* Still a small number run an average */
3722 		rack->r_ctl.gp_bw += bytes_ps;
3723 		rack->r_ctl.num_avg++;
3724 		if (rack->r_ctl.num_avg >= RACK_REQ_AVG) {
3725 			/* We have collected enought to move forward */
3726 			rack->r_ctl.gp_bw /= (uint64_t)rack->r_ctl.num_avg;
3727 		}
3728 	} else {
3729 		/*
3730 		 * We want to take 1/wma of the goodput and add in to 7/8th
3731 		 * of the old value weighted by the srtt. So if your measurement
3732 		 * period is say 2 SRTT's long you would get 1/4 as the
3733 		 * value, if it was like 1/2 SRTT then you would get 1/16th.
3734 		 *
3735 		 * But we must be careful not to take too much i.e. if the
3736 		 * srtt is say 20ms and the measurement is taken over
3737 		 * 400ms our weight would be 400/20 i.e. 20. On the
3738 		 * other hand if we get a measurement over 1ms with a
3739 		 * 10ms rtt we only want to take a much smaller portion.
3740 		 */
3741 		uint64_t  resid_bw, subpart, addpart, srtt;
3742 
3743 		srtt = ((uint64_t)TICKS_2_USEC(tp->t_srtt) >> TCP_RTT_SHIFT);
3744 		if (srtt == 0) {
3745 			/*
3746 			 * Strange why did t_srtt go back to zero?
3747 			 */
3748 			if (rack->r_ctl.rc_rack_min_rtt)
3749 				srtt = (rack->r_ctl.rc_rack_min_rtt * HPTS_USEC_IN_MSEC);
3750 			else
3751 				srtt = HPTS_USEC_IN_MSEC;
3752 		}
3753 		/*
3754 		 * XXXrrs: Note for reviewers, in playing with
3755 		 * dynamic pacing I discovered this GP calculation
3756 		 * as done originally leads to some undesired results.
3757 		 * Basically you can get longer measurements contributing
3758 		 * too much to the WMA. Thus I changed it if you are doing
3759 		 * dynamic adjustments to only do the aportioned adjustment
3760 		 * if we have a very small (time wise) measurement. Longer
3761 		 * measurements just get there weight (defaulting to 1/8)
3762 		 * add to the WMA. We may want to think about changing
3763 		 * this to always do that for both sides i.e. dynamic
3764 		 * and non-dynamic... but considering lots of folks
3765 		 * were playing with this I did not want to change the
3766 		 * calculation per.se. without your thoughts.. Lawerence?
3767 		 * Peter??
3768 		 */
3769 		if (rack->rc_gp_dyn_mul == 0) {
3770 			subpart = rack->r_ctl.gp_bw * utim;
3771 			subpart /= (srtt * 8);
3772 			if (subpart < (rack->r_ctl.gp_bw / 2)) {
3773 				/*
3774 				 * The b/w update takes no more
3775 				 * away then 1/2 our running total
3776 				 * so factor it in.
3777 				 */
3778 				addpart = bytes_ps * utim;
3779 				addpart /= (srtt * 8);
3780 			} else {
3781 				/*
3782 				 * Don't allow a single measurement
3783 				 * to account for more than 1/2 of the
3784 				 * WMA. This could happen on a retransmission
3785 				 * where utim becomes huge compared to
3786 				 * srtt (multiple retransmissions when using
3787 				 * the sending rate which factors in all the
3788 				 * transmissions from the first one).
3789 				 */
3790 				subpart = rack->r_ctl.gp_bw / 2;
3791 				addpart = bytes_ps / 2;
3792 			}
3793 			resid_bw = rack->r_ctl.gp_bw - subpart;
3794 			rack->r_ctl.gp_bw = resid_bw + addpart;
3795 		} else {
3796 			if ((utim / srtt) <= 1) {
3797 				/*
3798 				 * The b/w update was over a small period
3799 				 * of time. The idea here is to prevent a small
3800 				 * measurement time period from counting
3801 				 * too much. So we scale it based on the
3802 				 * time so it attributes less than 1/rack_wma_divisor
3803 				 * of its measurement.
3804 				 */
3805 				subpart = rack->r_ctl.gp_bw * utim;
3806 				subpart /= (srtt * rack_wma_divisor);
3807 				addpart = bytes_ps * utim;
3808 				addpart /= (srtt * rack_wma_divisor);
3809 			} else {
3810 				/*
3811 				 * The scaled measurement was long
3812 				 * enough so lets just add in the
3813 				 * portion of the measurment i.e. 1/rack_wma_divisor
3814 				 */
3815 				subpart = rack->r_ctl.gp_bw / rack_wma_divisor;
3816 				addpart = bytes_ps / rack_wma_divisor;
3817 			}
3818 			if ((rack->measure_saw_probe_rtt == 0) ||
3819 		            (bytes_ps > rack->r_ctl.gp_bw)) {
3820 				/*
3821 				 * For probe-rtt we only add it in
3822 				 * if its larger, all others we just
3823 				 * add in.
3824 				 */
3825 				resid_bw = rack->r_ctl.gp_bw - subpart;
3826 				rack->r_ctl.gp_bw = resid_bw + addpart;
3827 			}
3828 		}
3829 	}
3830 	/* We do not update any multipliers if we are in or have seen a probe-rtt */
3831 	if ((rack->measure_saw_probe_rtt == 0) && rack->rc_gp_rtt_set)
3832 		rack_update_multiplier(rack, timely_says, bytes_ps,
3833 				       rack->r_ctl.rc_gp_srtt,
3834 				       rack->r_ctl.rc_rtt_diff);
3835 	rack_log_pacing_delay_calc(rack, bytes, tim, bytes_ps, stim,
3836 				   rack_get_bw(rack), 3, line, NULL);
3837 	/* reset the gp srtt and setup the new prev */
3838 	rack->r_ctl.rc_prev_gp_srtt = rack->r_ctl.rc_gp_srtt;
3839 	/* Record the lost count for the next measurement */
3840 	rack->r_ctl.rc_loss_at_start = rack->r_ctl.rc_loss_count;
3841 	/*
3842 	 * We restart our diffs based on the gpsrtt in the
3843 	 * measurement window.
3844 	 */
3845 	rack->rc_gp_rtt_set = 0;
3846 	rack->rc_gp_saw_rec = 0;
3847 	rack->rc_gp_saw_ca = 0;
3848 	rack->rc_gp_saw_ss = 0;
3849 	rack->rc_dragged_bottom = 0;
3850 skip_measurement:
3851 
3852 #ifdef STATS
3853 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_GPUT,
3854 				 gput);
3855 	/*
3856 	 * XXXLAS: This is a temporary hack, and should be
3857 	 * chained off VOI_TCP_GPUT when stats(9) grows an
3858 	 * API to deal with chained VOIs.
3859 	 */
3860 	if (tp->t_stats_gput_prev > 0)
3861 		stats_voi_update_abs_s32(tp->t_stats,
3862 					 VOI_TCP_GPUT_ND,
3863 					 ((gput - tp->t_stats_gput_prev) * 100) /
3864 					 tp->t_stats_gput_prev);
3865 #endif
3866 	tp->t_flags &= ~TF_GPUTINPROG;
3867 	tp->t_stats_gput_prev = gput;
3868 	/*
3869 	 * Now are we app limited now and there is space from where we
3870 	 * were to where we want to go?
3871 	 *
3872 	 * We don't do the other case i.e. non-applimited here since
3873 	 * the next send will trigger us picking up the missing data.
3874 	 */
3875 	if (rack->r_ctl.rc_first_appl &&
3876 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
3877 	    rack->r_ctl.rc_app_limited_cnt &&
3878 	    (SEQ_GT(rack->r_ctl.rc_first_appl->r_start, th_ack)) &&
3879 	    ((rack->r_ctl.rc_first_appl->r_start - th_ack) >
3880 	     max(rc_init_window(rack), (MIN_GP_WIN * segsiz)))) {
3881 		/*
3882 		 * Yep there is enough outstanding to make a measurement here.
3883 		 */
3884 		struct rack_sendmap *rsm, fe;
3885 
3886 		tp->t_flags |= TF_GPUTINPROG;
3887 		rack->r_ctl.rc_gp_lowrtt = 0xffffffff;
3888 		rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
3889 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
3890 		rack->app_limited_needs_set = 0;
3891 		tp->gput_seq = th_ack;
3892 		if (rack->in_probe_rtt)
3893 			rack->measure_saw_probe_rtt = 1;
3894 		else if ((rack->measure_saw_probe_rtt) &&
3895 			 (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
3896 			rack->measure_saw_probe_rtt = 0;
3897 		if ((rack->r_ctl.rc_first_appl->r_start - th_ack) >= rack_get_measure_window(tp, rack)) {
3898 			/* There is a full window to gain info from */
3899 			tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
3900 		} else {
3901 			/* We can only measure up to the applimited point */
3902 			tp->gput_ack = tp->gput_seq + (rack->r_ctl.rc_first_appl->r_start - th_ack);
3903 		}
3904 		/*
3905 		 * Now we need to find the timestamp of the send at tp->gput_seq
3906 		 * for the send based measurement.
3907 		 */
3908 		fe.r_start = tp->gput_seq;
3909 		rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
3910 		if (rsm) {
3911 			/* Ok send-based limit is set */
3912 			if (SEQ_LT(rsm->r_start, tp->gput_seq)) {
3913 				/*
3914 				 * Move back to include the earlier part
3915 				 * so our ack time lines up right (this may
3916 				 * make an overlapping measurement but thats
3917 				 * ok).
3918 				 */
3919 				tp->gput_seq = rsm->r_start;
3920 			}
3921 			if (rsm->r_flags & RACK_ACKED)
3922 				tp->gput_ts = rsm->r_ack_arrival;
3923 			else
3924 				rack->app_limited_needs_set = 1;
3925 			rack->r_ctl.rc_gp_output_ts = rsm->usec_orig_send;
3926 		} else {
3927 			/*
3928 			 * If we don't find the rsm due to some
3929 			 * send-limit set the current time, which
3930 			 * basically disables the send-limit.
3931 			 */
3932 			rack->r_ctl.rc_gp_output_ts = tcp_get_usecs(NULL);
3933 		}
3934 		rack_log_pacing_delay_calc(rack,
3935 					   tp->gput_seq,
3936 					   tp->gput_ack,
3937 					   (uint64_t)rsm,
3938 					   tp->gput_ts,
3939 					   rack->r_ctl.rc_app_limited_cnt,
3940 					   9,
3941 					   __LINE__, NULL);
3942 	}
3943 }
3944 
3945 /*
3946  * CC wrapper hook functions
3947  */
3948 static void
3949 rack_ack_received(struct tcpcb *tp, struct tcp_rack *rack, struct tcphdr *th, uint16_t nsegs,
3950     uint16_t type, int32_t recovery)
3951 {
3952 	INP_WLOCK_ASSERT(tp->t_inpcb);
3953 	tp->ccv->nsegs = nsegs;
3954 	tp->ccv->bytes_this_ack = BYTES_THIS_ACK(tp, th);
3955 	if ((recovery) && (rack->r_ctl.rc_early_recovery_segs)) {
3956 		uint32_t max;
3957 
3958 		max = rack->r_ctl.rc_early_recovery_segs * ctf_fixed_maxseg(tp);
3959 		if (tp->ccv->bytes_this_ack > max) {
3960 			tp->ccv->bytes_this_ack = max;
3961 		}
3962 	}
3963 	if (rack->r_ctl.cwnd_to_use <= tp->snd_wnd)
3964 		tp->ccv->flags |= CCF_CWND_LIMITED;
3965 	else
3966 		tp->ccv->flags &= ~CCF_CWND_LIMITED;
3967 #ifdef STATS
3968 	stats_voi_update_abs_s32(tp->t_stats, VOI_TCP_CALCFRWINDIFF,
3969 	    ((int32_t)rack->r_ctl.cwnd_to_use) - tp->snd_wnd);
3970 #endif
3971 	if ((tp->t_flags & TF_GPUTINPROG) &&
3972 	    rack_enough_for_measurement(tp, rack, th->th_ack)) {
3973 		/* Measure the Goodput */
3974 		rack_do_goodput_measurement(tp, rack, th->th_ack, __LINE__);
3975 #ifdef NETFLIX_PEAKRATE
3976 		if ((type == CC_ACK) &&
3977 		    (tp->t_maxpeakrate)) {
3978 			/*
3979 			 * We update t_peakrate_thr. This gives us roughly
3980 			 * one update per round trip time. Note
3981 			 * it will only be used if pace_always is off i.e
3982 			 * we don't do this for paced flows.
3983 			 */
3984 			tcp_update_peakrate_thr(tp);
3985 		}
3986 #endif
3987 	}
3988 	if (rack->r_ctl.cwnd_to_use > tp->snd_ssthresh) {
3989 		tp->t_bytes_acked += min(tp->ccv->bytes_this_ack,
3990 			 nsegs * V_tcp_abc_l_var * ctf_fixed_maxseg(tp));
3991 		if (tp->t_bytes_acked >= rack->r_ctl.cwnd_to_use) {
3992 			tp->t_bytes_acked -= rack->r_ctl.cwnd_to_use;
3993 			tp->ccv->flags |= CCF_ABC_SENTAWND;
3994 		}
3995 	} else {
3996 		tp->ccv->flags &= ~CCF_ABC_SENTAWND;
3997 		tp->t_bytes_acked = 0;
3998 	}
3999 	if (CC_ALGO(tp)->ack_received != NULL) {
4000 		/* XXXLAS: Find a way to live without this */
4001 		tp->ccv->curack = th->th_ack;
4002 		CC_ALGO(tp)->ack_received(tp->ccv, type);
4003 	}
4004 #ifdef STATS
4005 	stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_LCWIN, rack->r_ctl.cwnd_to_use);
4006 #endif
4007 	if (rack->r_ctl.rc_rack_largest_cwnd < rack->r_ctl.cwnd_to_use) {
4008 		rack->r_ctl.rc_rack_largest_cwnd = rack->r_ctl.cwnd_to_use;
4009 	}
4010 #ifdef NETFLIX_PEAKRATE
4011 	/* we enforce max peak rate if it is set and we are not pacing */
4012 	if ((rack->rc_always_pace == 0) &&
4013 	    tp->t_peakrate_thr &&
4014 	    (tp->snd_cwnd > tp->t_peakrate_thr)) {
4015 		tp->snd_cwnd = tp->t_peakrate_thr;
4016 	}
4017 #endif
4018 }
4019 
4020 static void
4021 tcp_rack_partialack(struct tcpcb *tp, struct tcphdr *th)
4022 {
4023 	struct tcp_rack *rack;
4024 
4025 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4026 	INP_WLOCK_ASSERT(tp->t_inpcb);
4027 	/*
4028 	 * If we are doing PRR and have enough
4029 	 * room to send <or> we are pacing and prr
4030 	 * is disabled we will want to see if we
4031 	 * can send data (by setting r_wanted_output to
4032 	 * true).
4033 	 */
4034 	if ((rack->r_ctl.rc_prr_sndcnt > 0) ||
4035 	    rack->rack_no_prr)
4036 		rack->r_wanted_output = 1;
4037 }
4038 
4039 static void
4040 rack_post_recovery(struct tcpcb *tp, struct tcphdr *th)
4041 {
4042 	struct tcp_rack *rack;
4043 	uint32_t orig_cwnd;
4044 
4045 
4046 	orig_cwnd = tp->snd_cwnd;
4047 	INP_WLOCK_ASSERT(tp->t_inpcb);
4048 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4049 	if (rack->rc_not_backing_off == 0) {
4050 		/* only alert CC if we alerted when we entered */
4051 		if (CC_ALGO(tp)->post_recovery != NULL) {
4052 			tp->ccv->curack = th->th_ack;
4053 			CC_ALGO(tp)->post_recovery(tp->ccv);
4054 		}
4055 		if (tp->snd_cwnd > tp->snd_ssthresh) {
4056 			/* Drop us down to the ssthresh (1/2 cwnd at loss) */
4057 			tp->snd_cwnd = tp->snd_ssthresh;
4058 		}
4059 	}
4060 	if ((rack->rack_no_prr == 0) &&
4061 	    (rack->r_ctl.rc_prr_sndcnt > 0)) {
4062 		/* Suck the next prr cnt back into cwnd */
4063 		tp->snd_cwnd += rack->r_ctl.rc_prr_sndcnt;
4064 		rack->r_ctl.rc_prr_sndcnt = 0;
4065 		rack_log_to_prr(rack, 1, 0);
4066 	}
4067 	rack_log_to_prr(rack, 14, orig_cwnd);
4068 	tp->snd_recover = tp->snd_una;
4069 	EXIT_RECOVERY(tp->t_flags);
4070 }
4071 
4072 static void
4073 rack_cong_signal(struct tcpcb *tp, struct tcphdr *th, uint32_t type)
4074 {
4075 	struct tcp_rack *rack;
4076 
4077 	INP_WLOCK_ASSERT(tp->t_inpcb);
4078 
4079 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4080 	switch (type) {
4081 	case CC_NDUPACK:
4082 		tp->t_flags &= ~TF_WASFRECOVERY;
4083 		tp->t_flags &= ~TF_WASCRECOVERY;
4084 		if (!IN_FASTRECOVERY(tp->t_flags)) {
4085 			rack->r_ctl.rc_prr_delivered = 0;
4086 			rack->r_ctl.rc_prr_out = 0;
4087 			if (rack->rack_no_prr == 0) {
4088 				rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
4089 				rack_log_to_prr(rack, 2, 0);
4090 			}
4091 			rack->r_ctl.rc_prr_recovery_fs = tp->snd_max - tp->snd_una;
4092 			tp->snd_recover = tp->snd_max;
4093 			if (tp->t_flags2 & TF2_ECN_PERMIT)
4094 				tp->t_flags2 |= TF2_ECN_SND_CWR;
4095 		}
4096 		break;
4097 	case CC_ECN:
4098 		if (!IN_CONGRECOVERY(tp->t_flags) ||
4099 		    /*
4100 		     * Allow ECN reaction on ACK to CWR, if
4101 		     * that data segment was also CE marked.
4102 		     */
4103 		    SEQ_GEQ(th->th_ack, tp->snd_recover)) {
4104 			EXIT_CONGRECOVERY(tp->t_flags);
4105 			KMOD_TCPSTAT_INC(tcps_ecn_rcwnd);
4106 			tp->snd_recover = tp->snd_max + 1;
4107 			if (tp->t_flags2 & TF2_ECN_PERMIT)
4108 				tp->t_flags2 |= TF2_ECN_SND_CWR;
4109 		}
4110 		break;
4111 	case CC_RTO:
4112 		tp->t_dupacks = 0;
4113 		tp->t_bytes_acked = 0;
4114 		EXIT_RECOVERY(tp->t_flags);
4115 		tp->snd_ssthresh = max(2, min(tp->snd_wnd, rack->r_ctl.cwnd_to_use) / 2 /
4116 		    ctf_fixed_maxseg(tp)) * ctf_fixed_maxseg(tp);
4117 		tp->snd_cwnd = ctf_fixed_maxseg(tp);
4118 		if (tp->t_flags2 & TF2_ECN_PERMIT)
4119 			tp->t_flags2 |= TF2_ECN_SND_CWR;
4120 		break;
4121 	case CC_RTO_ERR:
4122 		KMOD_TCPSTAT_INC(tcps_sndrexmitbad);
4123 		/* RTO was unnecessary, so reset everything. */
4124 		tp->snd_cwnd = tp->snd_cwnd_prev;
4125 		tp->snd_ssthresh = tp->snd_ssthresh_prev;
4126 		tp->snd_recover = tp->snd_recover_prev;
4127 		if (tp->t_flags & TF_WASFRECOVERY) {
4128 			ENTER_FASTRECOVERY(tp->t_flags);
4129 			tp->t_flags &= ~TF_WASFRECOVERY;
4130 		}
4131 		if (tp->t_flags & TF_WASCRECOVERY) {
4132 			ENTER_CONGRECOVERY(tp->t_flags);
4133 			tp->t_flags &= ~TF_WASCRECOVERY;
4134 		}
4135 		tp->snd_nxt = tp->snd_max;
4136 		tp->t_badrxtwin = 0;
4137 		break;
4138 	}
4139 	/*
4140 	 * If we are below our max rtt, don't
4141 	 * signal the CC control to change things.
4142 	 * instead set it up so that we are in
4143 	 * recovery but not going to back off.
4144 	 */
4145 
4146 	if (rack->rc_highly_buffered) {
4147 		/*
4148 		 * Do we use the higher rtt for
4149 		 * our threshold to not backoff (like CDG)?
4150 		 */
4151 		uint32_t rtt_mul, rtt_div;
4152 
4153 		if (rack_use_max_for_nobackoff) {
4154 			rtt_mul = (rack_gp_rtt_maxmul - 1);
4155 			rtt_div = 1;
4156 		} else {
4157 			rtt_mul = rack_gp_rtt_minmul;
4158 			rtt_div = max(rack_gp_rtt_mindiv , 1);
4159 		}
4160 		if (rack->r_ctl.rc_gp_srtt <= (rack->r_ctl.rc_lowest_us_rtt +
4161 					       ((rack->r_ctl.rc_lowest_us_rtt * rtt_mul) /
4162 						rtt_div))) {
4163 			/* below our min threshold */
4164 			rack->rc_not_backing_off = 1;
4165 			ENTER_RECOVERY(rack->rc_tp->t_flags);
4166 			rack_log_rtt_shrinks(rack, 0,
4167 					     rtt_mul,
4168 					     rtt_div,
4169 					     RACK_RTTS_NOBACKOFF);
4170 			return;
4171 		}
4172 	}
4173 	rack->rc_not_backing_off = 0;
4174 	if (CC_ALGO(tp)->cong_signal != NULL) {
4175 		if (th != NULL)
4176 			tp->ccv->curack = th->th_ack;
4177 		CC_ALGO(tp)->cong_signal(tp->ccv, type);
4178 	}
4179 }
4180 
4181 
4182 
4183 static inline void
4184 rack_cc_after_idle(struct tcp_rack *rack, struct tcpcb *tp)
4185 {
4186 	uint32_t i_cwnd;
4187 
4188 	INP_WLOCK_ASSERT(tp->t_inpcb);
4189 
4190 #ifdef NETFLIX_STATS
4191 	KMOD_TCPSTAT_INC(tcps_idle_restarts);
4192 	if (tp->t_state == TCPS_ESTABLISHED)
4193 		KMOD_TCPSTAT_INC(tcps_idle_estrestarts);
4194 #endif
4195 	if (CC_ALGO(tp)->after_idle != NULL)
4196 		CC_ALGO(tp)->after_idle(tp->ccv);
4197 
4198 	if (tp->snd_cwnd == 1)
4199 		i_cwnd = tp->t_maxseg;		/* SYN(-ACK) lost */
4200 	else
4201 		i_cwnd = rc_init_window(rack);
4202 
4203 	/*
4204 	 * Being idle is no differnt than the initial window. If the cc
4205 	 * clamps it down below the initial window raise it to the initial
4206 	 * window.
4207 	 */
4208 	if (tp->snd_cwnd < i_cwnd) {
4209 		tp->snd_cwnd = i_cwnd;
4210 	}
4211 }
4212 
4213 
4214 /*
4215  * Indicate whether this ack should be delayed.  We can delay the ack if
4216  * following conditions are met:
4217  *	- There is no delayed ack timer in progress.
4218  *	- Our last ack wasn't a 0-sized window. We never want to delay
4219  *	  the ack that opens up a 0-sized window.
4220  *	- LRO wasn't used for this segment. We make sure by checking that the
4221  *	  segment size is not larger than the MSS.
4222  *	- Delayed acks are enabled or this is a half-synchronized T/TCP
4223  *	  connection.
4224  */
4225 #define DELAY_ACK(tp, tlen)			 \
4226 	(((tp->t_flags & TF_RXWIN0SENT) == 0) && \
4227 	((tp->t_flags & TF_DELACK) == 0) && 	 \
4228 	(tlen <= tp->t_maxseg) &&		 \
4229 	(tp->t_delayed_ack || (tp->t_flags & TF_NEEDSYN)))
4230 
4231 static struct rack_sendmap *
4232 rack_find_lowest_rsm(struct tcp_rack *rack)
4233 {
4234 	struct rack_sendmap *rsm;
4235 
4236 	/*
4237 	 * Walk the time-order transmitted list looking for an rsm that is
4238 	 * not acked. This will be the one that was sent the longest time
4239 	 * ago that is still outstanding.
4240 	 */
4241 	TAILQ_FOREACH(rsm, &rack->r_ctl.rc_tmap, r_tnext) {
4242 		if (rsm->r_flags & RACK_ACKED) {
4243 			continue;
4244 		}
4245 		goto finish;
4246 	}
4247 finish:
4248 	return (rsm);
4249 }
4250 
4251 static struct rack_sendmap *
4252 rack_find_high_nonack(struct tcp_rack *rack, struct rack_sendmap *rsm)
4253 {
4254 	struct rack_sendmap *prsm;
4255 
4256 	/*
4257 	 * Walk the sequence order list backward until we hit and arrive at
4258 	 * the highest seq not acked. In theory when this is called it
4259 	 * should be the last segment (which it was not).
4260 	 */
4261 	counter_u64_add(rack_find_high, 1);
4262 	prsm = rsm;
4263 	RB_FOREACH_REVERSE_FROM(prsm, rack_rb_tree_head, rsm) {
4264 		if (prsm->r_flags & (RACK_ACKED | RACK_HAS_FIN)) {
4265 			continue;
4266 		}
4267 		return (prsm);
4268 	}
4269 	return (NULL);
4270 }
4271 
4272 
4273 static uint32_t
4274 rack_calc_thresh_rack(struct tcp_rack *rack, uint32_t srtt, uint32_t cts)
4275 {
4276 	int32_t lro;
4277 	uint32_t thresh;
4278 
4279 	/*
4280 	 * lro is the flag we use to determine if we have seen reordering.
4281 	 * If it gets set we have seen reordering. The reorder logic either
4282 	 * works in one of two ways:
4283 	 *
4284 	 * If reorder-fade is configured, then we track the last time we saw
4285 	 * re-ordering occur. If we reach the point where enough time as
4286 	 * passed we no longer consider reordering has occuring.
4287 	 *
4288 	 * Or if reorder-face is 0, then once we see reordering we consider
4289 	 * the connection to alway be subject to reordering and just set lro
4290 	 * to 1.
4291 	 *
4292 	 * In the end if lro is non-zero we add the extra time for
4293 	 * reordering in.
4294 	 */
4295 	if (srtt == 0)
4296 		srtt = 1;
4297 	if (rack->r_ctl.rc_reorder_ts) {
4298 		if (rack->r_ctl.rc_reorder_fade) {
4299 			if (SEQ_GEQ(cts, rack->r_ctl.rc_reorder_ts)) {
4300 				lro = cts - rack->r_ctl.rc_reorder_ts;
4301 				if (lro == 0) {
4302 					/*
4303 					 * No time as passed since the last
4304 					 * reorder, mark it as reordering.
4305 					 */
4306 					lro = 1;
4307 				}
4308 			} else {
4309 				/* Negative time? */
4310 				lro = 0;
4311 			}
4312 			if (lro > rack->r_ctl.rc_reorder_fade) {
4313 				/* Turn off reordering seen too */
4314 				rack->r_ctl.rc_reorder_ts = 0;
4315 				lro = 0;
4316 			}
4317 		} else {
4318 			/* Reodering does not fade */
4319 			lro = 1;
4320 		}
4321 	} else {
4322 		lro = 0;
4323 	}
4324 	thresh = srtt + rack->r_ctl.rc_pkt_delay;
4325 	if (lro) {
4326 		/* It must be set, if not you get 1/4 rtt */
4327 		if (rack->r_ctl.rc_reorder_shift)
4328 			thresh += (srtt >> rack->r_ctl.rc_reorder_shift);
4329 		else
4330 			thresh += (srtt >> 2);
4331 	} else {
4332 		thresh += 1;
4333 	}
4334 	/* We don't let the rack timeout be above a RTO */
4335 	if (thresh > TICKS_2_MSEC(rack->rc_tp->t_rxtcur)) {
4336 		thresh = TICKS_2_MSEC(rack->rc_tp->t_rxtcur);
4337 	}
4338 	/* And we don't want it above the RTO max either */
4339 	if (thresh > rack_rto_max) {
4340 		thresh = rack_rto_max;
4341 	}
4342 	return (thresh);
4343 }
4344 
4345 static uint32_t
4346 rack_calc_thresh_tlp(struct tcpcb *tp, struct tcp_rack *rack,
4347 		     struct rack_sendmap *rsm, uint32_t srtt)
4348 {
4349 	struct rack_sendmap *prsm;
4350 	uint32_t thresh, len;
4351 	int segsiz;
4352 
4353 	if (srtt == 0)
4354 		srtt = 1;
4355 	if (rack->r_ctl.rc_tlp_threshold)
4356 		thresh = srtt + (srtt / rack->r_ctl.rc_tlp_threshold);
4357 	else
4358 		thresh = (srtt * 2);
4359 
4360 	/* Get the previous sent packet, if any  */
4361 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
4362 	counter_u64_add(rack_enter_tlp_calc, 1);
4363 	len = rsm->r_end - rsm->r_start;
4364 	if (rack->rack_tlp_threshold_use == TLP_USE_ID) {
4365 		/* Exactly like the ID */
4366 		if (((tp->snd_max - tp->snd_una) - rack->r_ctl.rc_sacked + rack->r_ctl.rc_holes_rxt) <= segsiz) {
4367 			uint32_t alt_thresh;
4368 			/*
4369 			 * Compensate for delayed-ack with the d-ack time.
4370 			 */
4371 			counter_u64_add(rack_used_tlpmethod, 1);
4372 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
4373 			if (alt_thresh > thresh)
4374 				thresh = alt_thresh;
4375 		}
4376 	} else if (rack->rack_tlp_threshold_use == TLP_USE_TWO_ONE) {
4377 		/* 2.1 behavior */
4378 		prsm = TAILQ_PREV(rsm, rack_head, r_tnext);
4379 		if (prsm && (len <= segsiz)) {
4380 			/*
4381 			 * Two packets outstanding, thresh should be (2*srtt) +
4382 			 * possible inter-packet delay (if any).
4383 			 */
4384 			uint32_t inter_gap = 0;
4385 			int idx, nidx;
4386 
4387 			counter_u64_add(rack_used_tlpmethod, 1);
4388 			idx = rsm->r_rtr_cnt - 1;
4389 			nidx = prsm->r_rtr_cnt - 1;
4390 			if (TSTMP_GEQ(rsm->r_tim_lastsent[nidx], prsm->r_tim_lastsent[idx])) {
4391 				/* Yes it was sent later (or at the same time) */
4392 				inter_gap = rsm->r_tim_lastsent[idx] - prsm->r_tim_lastsent[nidx];
4393 			}
4394 			thresh += inter_gap;
4395 		} else 	if (len <= segsiz) {
4396 			/*
4397 			 * Possibly compensate for delayed-ack.
4398 			 */
4399 			uint32_t alt_thresh;
4400 
4401 			counter_u64_add(rack_used_tlpmethod2, 1);
4402 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
4403 			if (alt_thresh > thresh)
4404 				thresh = alt_thresh;
4405 		}
4406 	} else if (rack->rack_tlp_threshold_use == TLP_USE_TWO_TWO) {
4407 		/* 2.2 behavior */
4408 		if (len <= segsiz) {
4409 			uint32_t alt_thresh;
4410 			/*
4411 			 * Compensate for delayed-ack with the d-ack time.
4412 			 */
4413 			counter_u64_add(rack_used_tlpmethod, 1);
4414 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
4415 			if (alt_thresh > thresh)
4416 				thresh = alt_thresh;
4417 		}
4418 	}
4419  	/* Not above an RTO */
4420 	if (thresh > TICKS_2_MSEC(tp->t_rxtcur)) {
4421 		thresh = TICKS_2_MSEC(tp->t_rxtcur);
4422 	}
4423 	/* Not above a RTO max */
4424 	if (thresh > rack_rto_max) {
4425 		thresh = rack_rto_max;
4426 	}
4427 	/* Apply user supplied min TLP */
4428 	if (thresh < rack_tlp_min) {
4429 		thresh = rack_tlp_min;
4430 	}
4431 	return (thresh);
4432 }
4433 
4434 static uint32_t
4435 rack_grab_rtt(struct tcpcb *tp, struct tcp_rack *rack)
4436 {
4437 	/*
4438 	 * We want the rack_rtt which is the
4439 	 * last rtt we measured. However if that
4440 	 * does not exist we fallback to the srtt (which
4441 	 * we probably will never do) and then as a last
4442 	 * resort we use RACK_INITIAL_RTO if no srtt is
4443 	 * yet set.
4444 	 */
4445 	if (rack->rc_rack_rtt)
4446 		return(rack->rc_rack_rtt);
4447 	else if (tp->t_srtt == 0)
4448 		return(RACK_INITIAL_RTO);
4449 	return (TICKS_2_MSEC(tp->t_srtt >> TCP_RTT_SHIFT));
4450 }
4451 
4452 static struct rack_sendmap *
4453 rack_check_recovery_mode(struct tcpcb *tp, uint32_t tsused)
4454 {
4455 	/*
4456 	 * Check to see that we don't need to fall into recovery. We will
4457 	 * need to do so if our oldest transmit is past the time we should
4458 	 * have had an ack.
4459 	 */
4460 	struct tcp_rack *rack;
4461 	struct rack_sendmap *rsm;
4462 	int32_t idx;
4463 	uint32_t srtt, thresh;
4464 
4465 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4466 	if (RB_EMPTY(&rack->r_ctl.rc_mtree)) {
4467 		return (NULL);
4468 	}
4469 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
4470 	if (rsm == NULL)
4471 		return (NULL);
4472 
4473 	if (rsm->r_flags & RACK_ACKED) {
4474 		rsm = rack_find_lowest_rsm(rack);
4475 		if (rsm == NULL)
4476 			return (NULL);
4477 	}
4478 	idx = rsm->r_rtr_cnt - 1;
4479 	srtt = rack_grab_rtt(tp, rack);
4480 	thresh = rack_calc_thresh_rack(rack, srtt, tsused);
4481 	if (TSTMP_LT(tsused, rsm->r_tim_lastsent[idx])) {
4482 		return (NULL);
4483 	}
4484 	if ((tsused - rsm->r_tim_lastsent[idx]) < thresh) {
4485 		return (NULL);
4486 	}
4487 	/* Ok if we reach here we are over-due and this guy can be sent */
4488 	if (IN_RECOVERY(tp->t_flags) == 0) {
4489 		/*
4490 		 * For the one that enters us into recovery record undo
4491 		 * info.
4492 		 */
4493 		rack->r_ctl.rc_rsm_start = rsm->r_start;
4494 		rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
4495 		rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
4496 	}
4497 	rack_cong_signal(tp, NULL, CC_NDUPACK);
4498 	return (rsm);
4499 }
4500 
4501 static uint32_t
4502 rack_get_persists_timer_val(struct tcpcb *tp, struct tcp_rack *rack)
4503 {
4504 	int32_t t;
4505 	int32_t tt;
4506 	uint32_t ret_val;
4507 
4508 	t = TICKS_2_MSEC((tp->t_srtt >> TCP_RTT_SHIFT) + ((tp->t_rttvar * 4) >> TCP_RTT_SHIFT));
4509 	TCPT_RANGESET(tt, t * tcp_backoff[tp->t_rxtshift],
4510 	    rack_persist_min, rack_persist_max);
4511 	if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
4512 		tp->t_rxtshift++;
4513 	rack->r_ctl.rc_hpts_flags |= PACE_TMR_PERSIT;
4514 	ret_val = (uint32_t)tt;
4515 	return (ret_val);
4516 }
4517 
4518 static uint32_t
4519 rack_timer_start(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int sup_rack)
4520 {
4521 	/*
4522 	 * Start the FR timer, we do this based on getting the first one in
4523 	 * the rc_tmap. Note that if its NULL we must stop the timer. in all
4524 	 * events we need to stop the running timer (if its running) before
4525 	 * starting the new one.
4526 	 */
4527 	uint32_t thresh, exp, to, srtt, time_since_sent, tstmp_touse;
4528 	uint32_t srtt_cur;
4529 	int32_t idx;
4530 	int32_t is_tlp_timer = 0;
4531 	struct rack_sendmap *rsm;
4532 
4533 	if (rack->t_timers_stopped) {
4534 		/* All timers have been stopped none are to run */
4535 		return (0);
4536 	}
4537 	if (rack->rc_in_persist) {
4538 		/* We can't start any timer in persists */
4539 		return (rack_get_persists_timer_val(tp, rack));
4540 	}
4541 	rack->rc_on_min_to = 0;
4542 	if ((tp->t_state < TCPS_ESTABLISHED) ||
4543 	    ((tp->t_flags & TF_SACK_PERMIT) == 0))
4544 		goto activate_rxt;
4545 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
4546 	if ((rsm == NULL) || sup_rack) {
4547 		/* Nothing on the send map */
4548 activate_rxt:
4549 		time_since_sent = 0;
4550 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
4551 		if (rsm) {
4552 			idx = rsm->r_rtr_cnt - 1;
4553 			if (TSTMP_GEQ(rsm->r_tim_lastsent[idx], rack->r_ctl.rc_tlp_rxt_last_time))
4554 				tstmp_touse = rsm->r_tim_lastsent[idx];
4555 			else
4556 				tstmp_touse = rack->r_ctl.rc_tlp_rxt_last_time;
4557 			if (TSTMP_GT(cts, tstmp_touse))
4558 			    time_since_sent = cts - tstmp_touse;
4559 		}
4560 		if (SEQ_LT(tp->snd_una, tp->snd_max) || sbavail(&(tp->t_inpcb->inp_socket->so_snd))) {
4561 			rack->r_ctl.rc_hpts_flags |= PACE_TMR_RXT;
4562 			to = TICKS_2_MSEC(tp->t_rxtcur);
4563 			if (to > time_since_sent)
4564 				to -= time_since_sent;
4565 			else
4566 				to = rack->r_ctl.rc_min_to;
4567 			if (to == 0)
4568 				to = 1;
4569 			return (to);
4570 		}
4571 		return (0);
4572 	}
4573 	if (rsm->r_flags & RACK_ACKED) {
4574 		rsm = rack_find_lowest_rsm(rack);
4575 		if (rsm == NULL) {
4576 			/* No lowest? */
4577 			goto activate_rxt;
4578 		}
4579 	}
4580 	if (rack->sack_attack_disable) {
4581 		/*
4582 		 * We don't want to do
4583 		 * any TLP's if you are an attacker.
4584 		 * Though if you are doing what
4585 		 * is expected you may still have
4586 		 * SACK-PASSED marks.
4587 		 */
4588 		goto activate_rxt;
4589 	}
4590 	/* Convert from ms to usecs */
4591 	if ((rsm->r_flags & RACK_SACK_PASSED) || (rsm->r_dupack >= DUP_ACK_THRESHOLD)) {
4592 		if ((tp->t_flags & TF_SENTFIN) &&
4593 		    ((tp->snd_max - tp->snd_una) == 1) &&
4594 		    (rsm->r_flags & RACK_HAS_FIN)) {
4595 			/*
4596 			 * We don't start a rack timer if all we have is a
4597 			 * FIN outstanding.
4598 			 */
4599 			goto activate_rxt;
4600 		}
4601 		if ((rack->use_rack_rr == 0) &&
4602 		    (IN_RECOVERY(tp->t_flags)) &&
4603 		    (rack->rack_no_prr == 0) &&
4604 		     (rack->r_ctl.rc_prr_sndcnt  < ctf_fixed_maxseg(tp))) {
4605 			/*
4606 			 * We are not cheating, in recovery  and
4607 			 * not enough ack's to yet get our next
4608 			 * retransmission out.
4609 			 *
4610 			 * Note that classified attackers do not
4611 			 * get to use the rack-cheat.
4612 			 */
4613 			goto activate_tlp;
4614 		}
4615 		srtt = rack_grab_rtt(tp, rack);
4616 		thresh = rack_calc_thresh_rack(rack, srtt, cts);
4617 		idx = rsm->r_rtr_cnt - 1;
4618 		exp = rsm->r_tim_lastsent[idx] + thresh;
4619 		if (SEQ_GEQ(exp, cts)) {
4620 			to = exp - cts;
4621 			if (to < rack->r_ctl.rc_min_to) {
4622 				to = rack->r_ctl.rc_min_to;
4623 				if (rack->r_rr_config == 3)
4624 					rack->rc_on_min_to = 1;
4625 			}
4626 		} else {
4627 			to = rack->r_ctl.rc_min_to;
4628 			if (rack->r_rr_config == 3)
4629 				rack->rc_on_min_to = 1;
4630 		}
4631 	} else {
4632 		/* Ok we need to do a TLP not RACK */
4633 activate_tlp:
4634 		if ((rack->rc_tlp_in_progress != 0) &&
4635 		    (rack->r_ctl.rc_tlp_cnt_out >= rack_tlp_limit)) {
4636 			/*
4637 			 * The previous send was a TLP and we have sent
4638 			 * N TLP's without sending new data.
4639 			 */
4640 			goto activate_rxt;
4641 		}
4642 		rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_tmap, rack_sendmap, r_tnext);
4643 		if (rsm == NULL) {
4644 			/* We found no rsm to TLP with. */
4645 			goto activate_rxt;
4646 		}
4647 		if (rsm->r_flags & RACK_HAS_FIN) {
4648 			/* If its a FIN we dont do TLP */
4649 			rsm = NULL;
4650 			goto activate_rxt;
4651 		}
4652 		idx = rsm->r_rtr_cnt - 1;
4653 		time_since_sent = 0;
4654 		if (TSTMP_GEQ(rsm->r_tim_lastsent[idx], rack->r_ctl.rc_tlp_rxt_last_time))
4655 			tstmp_touse = rsm->r_tim_lastsent[idx];
4656 		else
4657 			tstmp_touse = rack->r_ctl.rc_tlp_rxt_last_time;
4658 		if (TSTMP_GT(cts, tstmp_touse))
4659 		    time_since_sent = cts - tstmp_touse;
4660 		is_tlp_timer = 1;
4661 		if (tp->t_srtt) {
4662 			srtt_cur = (tp->t_srtt >> TCP_RTT_SHIFT);
4663 			srtt = TICKS_2_MSEC(srtt_cur);
4664 		} else
4665 			srtt = RACK_INITIAL_RTO;
4666 		/*
4667 		 * If the SRTT is not keeping up and the
4668 		 * rack RTT has spiked we want to use
4669 		 * the last RTT not the smoothed one.
4670 		 */
4671 		if (rack_tlp_use_greater && (srtt < rack_grab_rtt(tp, rack)))
4672 			srtt = rack_grab_rtt(tp, rack);
4673 		thresh = rack_calc_thresh_tlp(tp, rack, rsm, srtt);
4674 		if (thresh > time_since_sent)
4675 			to = thresh - time_since_sent;
4676 		else {
4677 			to = rack->r_ctl.rc_min_to;
4678 			rack_log_alt_to_to_cancel(rack,
4679 						  thresh,		/* flex1 */
4680 						  time_since_sent,	/* flex2 */
4681 						  tstmp_touse,		/* flex3 */
4682 						  rack->r_ctl.rc_tlp_rxt_last_time, /* flex4 */
4683 						  rsm->r_tim_lastsent[idx],
4684 						  srtt,
4685 						  idx, 99);
4686 		}
4687 		if (to > TCPTV_REXMTMAX) {
4688 			/*
4689 			 * If the TLP time works out to larger than the max
4690 			 * RTO lets not do TLP.. just RTO.
4691 			 */
4692 			goto activate_rxt;
4693 		}
4694 	}
4695 	if (is_tlp_timer == 0) {
4696 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_RACK;
4697 	} else {
4698 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_TLP;
4699 	}
4700 	if (to == 0)
4701 		to = 1;
4702 	return (to);
4703 }
4704 
4705 static void
4706 rack_enter_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
4707 {
4708 	if (rack->rc_in_persist == 0) {
4709 		if (tp->t_flags & TF_GPUTINPROG) {
4710 			/*
4711 			 * Stop the goodput now, the calling of the
4712 			 * measurement function clears the flag.
4713 			 */
4714 			rack_do_goodput_measurement(tp, rack, tp->snd_una, __LINE__);
4715 		}
4716 #ifdef NETFLIX_SHARED_CWND
4717 		if (rack->r_ctl.rc_scw) {
4718 			tcp_shared_cwnd_idle(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
4719 			rack->rack_scwnd_is_idle = 1;
4720 		}
4721 #endif
4722 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
4723 		if (rack->r_ctl.rc_went_idle_time == 0)
4724 			rack->r_ctl.rc_went_idle_time = 1;
4725 		rack_timer_cancel(tp, rack, cts, __LINE__);
4726 		tp->t_rxtshift = 0;
4727 		rack->rc_in_persist = 1;
4728 	}
4729 }
4730 
4731 static void
4732 rack_exit_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
4733 {
4734 	if (rack->rc_inp->inp_in_hpts)  {
4735 		tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
4736 		rack->r_ctl.rc_hpts_flags  = 0;
4737 	}
4738 #ifdef NETFLIX_SHARED_CWND
4739 	if (rack->r_ctl.rc_scw) {
4740 		tcp_shared_cwnd_active(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
4741 		rack->rack_scwnd_is_idle = 0;
4742 	}
4743 #endif
4744 	if (rack->rc_gp_dyn_mul &&
4745 	    (rack->use_fixed_rate == 0) &&
4746 	    (rack->rc_always_pace)) {
4747 		/*
4748 		 * Do we count this as if a probe-rtt just
4749 		 * finished?
4750 		 */
4751 		uint32_t time_idle, idle_min;
4752 
4753 		time_idle = tcp_get_usecs(NULL) - rack->r_ctl.rc_went_idle_time;
4754 		idle_min = rack_min_probertt_hold;
4755 		if (rack_probertt_gpsrtt_cnt_div) {
4756 			uint64_t extra;
4757 			extra = (uint64_t)rack->r_ctl.rc_gp_srtt *
4758 				(uint64_t)rack_probertt_gpsrtt_cnt_mul;
4759 			extra /= (uint64_t)rack_probertt_gpsrtt_cnt_div;
4760 			idle_min += (uint32_t)extra;
4761 		}
4762 		if (time_idle >= idle_min)  {
4763 			/* Yes, we count it as a probe-rtt. */
4764 			uint32_t us_cts;
4765 
4766 			us_cts = tcp_get_usecs(NULL);
4767 			if (rack->in_probe_rtt == 0) {
4768 				rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
4769 				rack->r_ctl.rc_time_probertt_entered = rack->r_ctl.rc_lower_rtt_us_cts;
4770 				rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts;
4771 				rack->r_ctl.rc_time_of_last_probertt = rack->r_ctl.rc_lower_rtt_us_cts;
4772 			} else {
4773 				rack_exit_probertt(rack, us_cts);
4774 			}
4775 		}
4776 
4777 	}
4778 	rack->rc_in_persist = 0;
4779 	rack->r_ctl.rc_went_idle_time = 0;
4780 	tp->t_rxtshift = 0;
4781  	rack->r_ctl.rc_agg_delayed = 0;
4782 	rack->r_early = 0;
4783 	rack->r_late = 0;
4784 	rack->r_ctl.rc_agg_early = 0;
4785 }
4786 
4787 static void
4788 rack_log_hpts_diag(struct tcp_rack *rack, uint32_t cts,
4789 		   struct hpts_diag *diag, struct timeval *tv)
4790 {
4791 	if (rack_verbose_logging && rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
4792 		union tcp_log_stackspecific log;
4793 
4794 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
4795 		log.u_bbr.flex1 = diag->p_nxt_slot;
4796 		log.u_bbr.flex2 = diag->p_cur_slot;
4797 		log.u_bbr.flex3 = diag->slot_req;
4798 		log.u_bbr.flex4 = diag->inp_hptsslot;
4799 		log.u_bbr.flex5 = diag->slot_remaining;
4800 		log.u_bbr.flex6 = diag->need_new_to;
4801 		log.u_bbr.flex7 = diag->p_hpts_active;
4802 		log.u_bbr.flex8 = diag->p_on_min_sleep;
4803 		/* Hijack other fields as needed  */
4804 		log.u_bbr.epoch = diag->have_slept;
4805 		log.u_bbr.lt_epoch = diag->yet_to_sleep;
4806 		log.u_bbr.pkts_out = diag->co_ret;
4807 		log.u_bbr.applimited = diag->hpts_sleep_time;
4808 		log.u_bbr.delivered = diag->p_prev_slot;
4809 		log.u_bbr.inflight = diag->p_runningtick;
4810 		log.u_bbr.bw_inuse = diag->wheel_tick;
4811 		log.u_bbr.rttProp = diag->wheel_cts;
4812 		log.u_bbr.timeStamp = cts;
4813 		log.u_bbr.delRate = diag->maxticks;
4814 		log.u_bbr.cur_del_rate = diag->p_curtick;
4815 		log.u_bbr.cur_del_rate <<= 32;
4816 		log.u_bbr.cur_del_rate |= diag->p_lasttick;
4817 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
4818 		    &rack->rc_inp->inp_socket->so_rcv,
4819 		    &rack->rc_inp->inp_socket->so_snd,
4820 		    BBR_LOG_HPTSDIAG, 0,
4821 		    0, &log, false, tv);
4822 	}
4823 
4824 }
4825 
4826 static void
4827 rack_start_hpts_timer(struct tcp_rack *rack, struct tcpcb *tp, uint32_t cts,
4828       int32_t slot, uint32_t tot_len_this_send, int sup_rack)
4829 {
4830 	struct hpts_diag diag;
4831 	struct inpcb *inp;
4832 	struct timeval tv;
4833 	uint32_t delayed_ack = 0;
4834 	uint32_t hpts_timeout;
4835 	uint8_t stopped;
4836 	uint32_t left = 0;
4837 	uint32_t us_cts;
4838 
4839 	inp = tp->t_inpcb;
4840 	if ((tp->t_state == TCPS_CLOSED) ||
4841 	    (tp->t_state == TCPS_LISTEN)) {
4842 		return;
4843 	}
4844 	if (inp->inp_in_hpts) {
4845 		/* Already on the pacer */
4846 		return;
4847 	}
4848 	stopped = rack->rc_tmr_stopped;
4849 	if (stopped && TSTMP_GT(rack->r_ctl.rc_timer_exp, cts)) {
4850 		left = rack->r_ctl.rc_timer_exp - cts;
4851 	}
4852 	rack->r_ctl.rc_timer_exp = 0;
4853 	rack->r_ctl.rc_hpts_flags = 0;
4854 	us_cts = tcp_get_usecs(&tv);
4855 	/* Now early/late accounting */
4856 	if (rack->r_early) {
4857 		/*
4858 		 * We have a early carry over set,
4859 		 * we can always add more time so we
4860 		 * can always make this compensation.
4861 		 */
4862 		slot += rack->r_ctl.rc_agg_early;
4863 		rack->r_early = 0;
4864 		rack->r_ctl.rc_agg_early = 0;
4865 	}
4866 	if (rack->r_late) {
4867 		/*
4868 		 * This is harder, we can
4869 		 * compensate some but it
4870 		 * really depends on what
4871 		 * the current pacing time is.
4872 		 */
4873 		if (rack->r_ctl.rc_agg_delayed >= slot) {
4874 			/*
4875 			 * We can't compensate for it all.
4876 			 * And we have to have some time
4877 			 * on the clock. We always have a min
4878 			 * 10 slots (10 x 10 i.e. 100 usecs).
4879 			 */
4880 			if (slot <= HPTS_TICKS_PER_USEC) {
4881 				/* We gain delay */
4882 				rack->r_ctl.rc_agg_delayed += (HPTS_TICKS_PER_USEC - slot);
4883 				slot = HPTS_TICKS_PER_USEC;
4884 			} else {
4885 				/* We take off some */
4886 				rack->r_ctl.rc_agg_delayed -= (slot - HPTS_TICKS_PER_USEC);
4887 				slot = HPTS_TICKS_PER_USEC;
4888 			}
4889 		} else {
4890 
4891 			slot -= rack->r_ctl.rc_agg_delayed;
4892 			rack->r_ctl.rc_agg_delayed = 0;
4893 			/* Make sure we have 100 useconds at minimum */
4894 			if (slot < HPTS_TICKS_PER_USEC) {
4895 				rack->r_ctl.rc_agg_delayed = HPTS_TICKS_PER_USEC - slot;
4896 				slot = HPTS_TICKS_PER_USEC;
4897 			}
4898 			if (rack->r_ctl.rc_agg_delayed == 0)
4899 				rack->r_late = 0;
4900 		}
4901 	}
4902 	if (slot) {
4903 		/* We are pacing too */
4904 		rack->r_ctl.rc_hpts_flags |= PACE_PKT_OUTPUT;
4905 	}
4906 	hpts_timeout = rack_timer_start(tp, rack, cts, sup_rack);
4907 #ifdef NETFLIX_EXP_DETECTION
4908 	if (rack->sack_attack_disable &&
4909 	    (slot < tcp_sad_pacing_interval)) {
4910 		/*
4911 		 * We have a potential attacker on
4912 		 * the line. We have possibly some
4913 		 * (or now) pacing time set. We want to
4914 		 * slow down the processing of sacks by some
4915 		 * amount (if it is an attacker). Set the default
4916 		 * slot for attackers in place (unless the orginal
4917 		 * interval is longer). Its stored in
4918 		 * micro-seconds, so lets convert to msecs.
4919 		 */
4920 		slot = tcp_sad_pacing_interval;
4921 	}
4922 #endif
4923 	if (tp->t_flags & TF_DELACK) {
4924 		delayed_ack = TICKS_2_MSEC(tcp_delacktime);
4925 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_DELACK;
4926 	}
4927 	if (delayed_ack && ((hpts_timeout == 0) ||
4928 			    (delayed_ack < hpts_timeout)))
4929 		hpts_timeout = delayed_ack;
4930 	else
4931 		rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK;
4932 	/*
4933 	 * If no timers are going to run and we will fall off the hptsi
4934 	 * wheel, we resort to a keep-alive timer if its configured.
4935 	 */
4936 	if ((hpts_timeout == 0) &&
4937 	    (slot == 0)) {
4938 		if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
4939 		    (tp->t_state <= TCPS_CLOSING)) {
4940 			/*
4941 			 * Ok we have no timer (persists, rack, tlp, rxt  or
4942 			 * del-ack), we don't have segments being paced. So
4943 			 * all that is left is the keepalive timer.
4944 			 */
4945 			if (TCPS_HAVEESTABLISHED(tp->t_state)) {
4946 				/* Get the established keep-alive time */
4947 				hpts_timeout = TP_KEEPIDLE(tp);
4948 			} else {
4949 				/* Get the initial setup keep-alive time */
4950 				hpts_timeout = TP_KEEPINIT(tp);
4951 			}
4952 			rack->r_ctl.rc_hpts_flags |= PACE_TMR_KEEP;
4953 			if (rack->in_probe_rtt) {
4954 				/*
4955 				 * We want to instead not wake up a long time from
4956 				 * now but to wake up about the time we would
4957 				 * exit probe-rtt and initiate a keep-alive ack.
4958 				 * This will get us out of probe-rtt and update
4959 				 * our min-rtt.
4960 				 */
4961 				hpts_timeout = (rack_min_probertt_hold / HPTS_USEC_IN_MSEC);
4962 			}
4963 		}
4964 	}
4965 	if (left && (stopped & (PACE_TMR_KEEP | PACE_TMR_DELACK)) ==
4966 	    (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK)) {
4967 		/*
4968 		 * RACK, TLP, persists and RXT timers all are restartable
4969 		 * based on actions input .. i.e we received a packet (ack
4970 		 * or sack) and that changes things (rw, or snd_una etc).
4971 		 * Thus we can restart them with a new value. For
4972 		 * keep-alive, delayed_ack we keep track of what was left
4973 		 * and restart the timer with a smaller value.
4974 		 */
4975 		if (left < hpts_timeout)
4976 			hpts_timeout = left;
4977 	}
4978 	if (hpts_timeout) {
4979 		/*
4980 		 * Hack alert for now we can't time-out over 2,147,483
4981 		 * seconds (a bit more than 596 hours), which is probably ok
4982 		 * :).
4983 		 */
4984 		if (hpts_timeout > 0x7ffffffe)
4985 			hpts_timeout = 0x7ffffffe;
4986 		rack->r_ctl.rc_timer_exp = cts + hpts_timeout;
4987 	}
4988 	if ((rack->rc_gp_filled == 0) &&
4989 	    (hpts_timeout < slot) &&
4990 	    (rack->r_ctl.rc_hpts_flags & (PACE_TMR_TLP|PACE_TMR_RXT))) {
4991 		/*
4992 		 * We have no good estimate yet for the
4993 		 * old clunky burst mitigation or the
4994 		 * real pacing. And the tlp or rxt is smaller
4995 		 * than the pacing calculation. Lets not
4996 		 * pace that long since we know the calculation
4997 		 * so far is not accurate.
4998 		 */
4999 		slot = hpts_timeout;
5000 	}
5001 	rack->r_ctl.last_pacing_time = slot;
5002 	if (slot) {
5003 		rack->r_ctl.rc_last_output_to = us_cts + slot;
5004 		if (rack->rc_always_pace || rack->r_mbuf_queue) {
5005 			if ((rack->rc_gp_filled == 0) ||
5006 			    rack->pacing_longer_than_rtt) {
5007 				inp->inp_flags2 &= ~(INP_DONT_SACK_QUEUE|INP_MBUF_QUEUE_READY);
5008 			} else {
5009 				inp->inp_flags2 |= INP_MBUF_QUEUE_READY;
5010 				if ((rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK) &&
5011 				    (rack->r_rr_config != 3))
5012 					inp->inp_flags2 |= INP_DONT_SACK_QUEUE;
5013 				else
5014 					inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
5015 			}
5016 		}
5017 		if ((rack->use_rack_rr) &&
5018 		    (rack->r_rr_config < 2) &&
5019 		    ((hpts_timeout) && ((hpts_timeout * HPTS_USEC_IN_MSEC) < slot))) {
5020 			/*
5021 			 * Arrange for the hpts to kick back in after the
5022 			 * t-o if the t-o does not cause a send.
5023 			 */
5024 			(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_MS_TO_SLOTS(hpts_timeout),
5025 						   __LINE__, &diag);
5026 			rack_log_hpts_diag(rack, us_cts, &diag, &tv);
5027 			rack_log_to_start(rack, cts, hpts_timeout, slot, 0);
5028 		} else {
5029 			(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_USEC_TO_SLOTS(slot),
5030 						   __LINE__, &diag);
5031 			rack_log_hpts_diag(rack, us_cts, &diag, &tv);
5032 			rack_log_to_start(rack, cts, hpts_timeout, slot, 1);
5033 		}
5034 	} else if (hpts_timeout) {
5035 		if (rack->rc_always_pace || rack->r_mbuf_queue) {
5036 			if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK)  {
5037 				/* For a rack timer, don't wake us */
5038 				inp->inp_flags2 |= INP_MBUF_QUEUE_READY;
5039 				if  (rack->r_rr_config != 3)
5040 					inp->inp_flags2 |= INP_DONT_SACK_QUEUE;
5041 				else
5042 					inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
5043 			} else {
5044 				/* All other timers wake us up */
5045 				inp->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
5046 				inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
5047 			}
5048 		}
5049 		(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_MS_TO_SLOTS(hpts_timeout),
5050 					   __LINE__, &diag);
5051 		rack_log_hpts_diag(rack, us_cts, &diag, &tv);
5052 		rack_log_to_start(rack, cts, hpts_timeout, slot, 0);
5053 	} else {
5054 		/* No timer starting */
5055 #ifdef INVARIANTS
5056 		if (SEQ_GT(tp->snd_max, tp->snd_una)) {
5057 			panic("tp:%p rack:%p tlts:%d cts:%u slot:%u pto:%u -- no timer started?",
5058 			    tp, rack, tot_len_this_send, cts, slot, hpts_timeout);
5059 		}
5060 #endif
5061 	}
5062 	rack->rc_tmr_stopped = 0;
5063 	if (slot)
5064 		rack_log_type_bbrsnd(rack, tot_len_this_send, slot, us_cts, &tv);
5065 }
5066 
5067 /*
5068  * RACK Timer, here we simply do logging and house keeping.
5069  * the normal rack_output() function will call the
5070  * appropriate thing to check if we need to do a RACK retransmit.
5071  * We return 1, saying don't proceed with rack_output only
5072  * when all timers have been stopped (destroyed PCB?).
5073  */
5074 static int
5075 rack_timeout_rack(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5076 {
5077 	/*
5078 	 * This timer simply provides an internal trigger to send out data.
5079 	 * The check_recovery_mode call will see if there are needed
5080 	 * retransmissions, if so we will enter fast-recovery. The output
5081 	 * call may or may not do the same thing depending on sysctl
5082 	 * settings.
5083 	 */
5084 	struct rack_sendmap *rsm;
5085 	int32_t recovery;
5086 
5087 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5088 		return (1);
5089 	}
5090 	recovery = IN_RECOVERY(tp->t_flags);
5091 	counter_u64_add(rack_to_tot, 1);
5092 	if (rack->r_state && (rack->r_state != tp->t_state))
5093 		rack_set_state(tp, rack);
5094 	rack->rc_on_min_to = 0;
5095 	rsm = rack_check_recovery_mode(tp, cts);
5096 	rack_log_to_event(rack, RACK_TO_FRM_RACK, rsm);
5097 	if (rsm) {
5098 		uint32_t rtt;
5099 
5100 		rack->r_ctl.rc_resend = rsm;
5101 		if (rack->use_rack_rr) {
5102 			/*
5103 			 * Don't accumulate extra pacing delay
5104 			 * we are allowing the rack timer to
5105 			 * over-ride pacing i.e. rrr takes precedence
5106 			 * if the pacing interval is longer than the rrr
5107 			 * time (in other words we get the min pacing
5108 			 * time versus rrr pacing time).
5109 			 */
5110 			rack->r_timer_override = 1;
5111 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
5112 		}
5113 		rtt = rack->rc_rack_rtt;
5114 		if (rtt == 0)
5115 			rtt = 1;
5116 		if (rack->rack_no_prr == 0) {
5117 			if ((recovery == 0) &&
5118 			    (rack->r_ctl.rc_prr_sndcnt < ctf_fixed_maxseg(tp))) {
5119 				/*
5120 				 * The rack-timeout that enter's us into recovery
5121 				 * will force out one MSS and set us up so that we
5122 				 * can do one more send in 2*rtt (transitioning the
5123 				 * rack timeout into a rack-tlp).
5124 				 */
5125 				rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
5126 				rack->r_timer_override = 1;
5127 				rack_log_to_prr(rack, 3, 0);
5128 			} else if ((rack->r_ctl.rc_prr_sndcnt < (rsm->r_end - rsm->r_start)) &&
5129 				   rack->use_rack_rr) {
5130 				/*
5131 				 * When a rack timer goes, if the rack rr is
5132 				 * on, arrange it so we can send a full segment
5133 				 * overriding prr (though we pay a price for this
5134 				 * for future new sends).
5135 				 */
5136 				rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
5137 				rack_log_to_prr(rack, 4, 0);
5138 			}
5139 		}
5140 	}
5141 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_RACK;
5142 	if (rsm == NULL) {
5143 		/* restart a timer and return 1 */
5144 		rack_start_hpts_timer(rack, tp, cts,
5145 				      0, 0, 0);
5146 		return (1);
5147 	}
5148 	return (0);
5149 }
5150 
5151 static __inline void
5152 rack_clone_rsm(struct tcp_rack *rack, struct rack_sendmap *nrsm,
5153 	       struct rack_sendmap *rsm, uint32_t start)
5154 {
5155 	int idx;
5156 
5157 	nrsm->r_start = start;
5158 	nrsm->r_end = rsm->r_end;
5159 	nrsm->r_rtr_cnt = rsm->r_rtr_cnt;
5160 	nrsm->r_flags = rsm->r_flags;
5161 	nrsm->r_dupack = rsm->r_dupack;
5162 	nrsm->usec_orig_send = rsm->usec_orig_send;
5163 	nrsm->r_rtr_bytes = 0;
5164 	rsm->r_end = nrsm->r_start;
5165 	nrsm->r_just_ret = rsm->r_just_ret;
5166 	for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) {
5167 		nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx];
5168 	}
5169 }
5170 
5171 static struct rack_sendmap *
5172 rack_merge_rsm(struct tcp_rack *rack,
5173 	       struct rack_sendmap *l_rsm,
5174 	       struct rack_sendmap *r_rsm)
5175 {
5176 	/*
5177 	 * We are merging two ack'd RSM's,
5178 	 * the l_rsm is on the left (lower seq
5179 	 * values) and the r_rsm is on the right
5180 	 * (higher seq value). The simplest way
5181 	 * to merge these is to move the right
5182 	 * one into the left. I don't think there
5183 	 * is any reason we need to try to find
5184 	 * the oldest (or last oldest retransmitted).
5185 	 */
5186 	struct rack_sendmap *rm;
5187 
5188 	l_rsm->r_end = r_rsm->r_end;
5189 	if (l_rsm->r_dupack < r_rsm->r_dupack)
5190 		l_rsm->r_dupack = r_rsm->r_dupack;
5191 	if (r_rsm->r_rtr_bytes)
5192 		l_rsm->r_rtr_bytes += r_rsm->r_rtr_bytes;
5193 	if (r_rsm->r_in_tmap) {
5194 		/* This really should not happen */
5195 		TAILQ_REMOVE(&rack->r_ctl.rc_tmap, r_rsm, r_tnext);
5196 		r_rsm->r_in_tmap = 0;
5197 	}
5198 
5199 	/* Now the flags */
5200 	if (r_rsm->r_flags & RACK_HAS_FIN)
5201 		l_rsm->r_flags |= RACK_HAS_FIN;
5202 	if (r_rsm->r_flags & RACK_TLP)
5203 		l_rsm->r_flags |= RACK_TLP;
5204 	if (r_rsm->r_flags & RACK_RWND_COLLAPSED)
5205 		l_rsm->r_flags |= RACK_RWND_COLLAPSED;
5206 	if ((r_rsm->r_flags & RACK_APP_LIMITED)  &&
5207 	    ((l_rsm->r_flags & RACK_APP_LIMITED) == 0)) {
5208 		/*
5209 		 * If both are app-limited then let the
5210 		 * free lower the count. If right is app
5211 		 * limited and left is not, transfer.
5212 		 */
5213 		l_rsm->r_flags |= RACK_APP_LIMITED;
5214 		r_rsm->r_flags &= ~RACK_APP_LIMITED;
5215 		if (r_rsm == rack->r_ctl.rc_first_appl)
5216 			rack->r_ctl.rc_first_appl = l_rsm;
5217 	}
5218 	rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, r_rsm);
5219 #ifdef INVARIANTS
5220 	if (rm != r_rsm) {
5221 		panic("removing head in rack:%p rsm:%p rm:%p",
5222 		      rack, r_rsm, rm);
5223 	}
5224 #endif
5225 	if ((r_rsm->r_limit_type == 0) && (l_rsm->r_limit_type != 0)) {
5226 		/* Transfer the split limit to the map we free */
5227 		r_rsm->r_limit_type = l_rsm->r_limit_type;
5228 		l_rsm->r_limit_type = 0;
5229 	}
5230 	rack_free(rack, r_rsm);
5231 	return(l_rsm);
5232 }
5233 
5234 /*
5235  * TLP Timer, here we simply setup what segment we want to
5236  * have the TLP expire on, the normal rack_output() will then
5237  * send it out.
5238  *
5239  * We return 1, saying don't proceed with rack_output only
5240  * when all timers have been stopped (destroyed PCB?).
5241  */
5242 static int
5243 rack_timeout_tlp(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5244 {
5245 	/*
5246 	 * Tail Loss Probe.
5247 	 */
5248 	struct rack_sendmap *rsm = NULL;
5249 	struct rack_sendmap *insret;
5250 	struct socket *so;
5251 	uint32_t amm, old_prr_snd = 0;
5252 	uint32_t out, avail;
5253 	int collapsed_win = 0;
5254 
5255 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5256 		return (1);
5257 	}
5258 	if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) {
5259 		/* Its not time yet */
5260 		return (0);
5261 	}
5262 	if (ctf_progress_timeout_check(tp, true)) {
5263 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
5264 		tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
5265 		return (1);
5266 	}
5267 	/*
5268 	 * A TLP timer has expired. We have been idle for 2 rtts. So we now
5269 	 * need to figure out how to force a full MSS segment out.
5270 	 */
5271 	rack_log_to_event(rack, RACK_TO_FRM_TLP, NULL);
5272 	counter_u64_add(rack_tlp_tot, 1);
5273 	if (rack->r_state && (rack->r_state != tp->t_state))
5274 		rack_set_state(tp, rack);
5275 	so = tp->t_inpcb->inp_socket;
5276 #ifdef KERN_TLS
5277 	if (rack->rc_inp->inp_socket->so_snd.sb_flags & SB_TLS_IFNET) {
5278 		/*
5279 		 * For hardware TLS we do *not* want to send
5280 		 * new data, lets instead just do a retransmission.
5281 		 */
5282 		goto need_retran;
5283 	}
5284 #endif
5285 	avail = sbavail(&so->so_snd);
5286 	out = tp->snd_max - tp->snd_una;
5287 	if (out > tp->snd_wnd) {
5288 		/* special case, we need a retransmission */
5289 		collapsed_win = 1;
5290 		goto need_retran;
5291 	}
5292 	/*
5293 	 * Check our send oldest always settings, and if
5294 	 * there is an oldest to send jump to the need_retran.
5295 	 */
5296 	if (rack_always_send_oldest && (TAILQ_EMPTY(&rack->r_ctl.rc_tmap) == 0))
5297 		goto need_retran;
5298 
5299 	if (avail > out) {
5300 		/* New data is available */
5301 		amm = avail - out;
5302 		if (amm > ctf_fixed_maxseg(tp)) {
5303 			amm = ctf_fixed_maxseg(tp);
5304 			if ((amm + out) > tp->snd_wnd) {
5305 				/* We are rwnd limited */
5306 				goto need_retran;
5307 			}
5308 		} else if (amm < ctf_fixed_maxseg(tp)) {
5309 			/* not enough to fill a MTU */
5310 			goto need_retran;
5311 		}
5312 		if (IN_RECOVERY(tp->t_flags)) {
5313 			/* Unlikely */
5314 			if (rack->rack_no_prr == 0) {
5315 				old_prr_snd = rack->r_ctl.rc_prr_sndcnt;
5316 				if (out + amm <= tp->snd_wnd) {
5317 					rack->r_ctl.rc_prr_sndcnt = amm;
5318 					rack_log_to_prr(rack, 4, 0);
5319 				}
5320 			} else
5321 				goto need_retran;
5322 		} else {
5323 			/* Set the send-new override */
5324 			if (out + amm <= tp->snd_wnd)
5325 				rack->r_ctl.rc_tlp_new_data = amm;
5326 			else
5327 				goto need_retran;
5328 		}
5329 		rack->r_ctl.rc_tlpsend = NULL;
5330 		counter_u64_add(rack_tlp_newdata, 1);
5331 		goto send;
5332 	}
5333 need_retran:
5334 	/*
5335 	 * Ok we need to arrange the last un-acked segment to be re-sent, or
5336 	 * optionally the first un-acked segment.
5337 	 */
5338 	if (collapsed_win == 0) {
5339 		if (rack_always_send_oldest)
5340 			rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
5341 		else {
5342 			rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
5343 			if (rsm && (rsm->r_flags & (RACK_ACKED | RACK_HAS_FIN))) {
5344 				rsm = rack_find_high_nonack(rack, rsm);
5345 			}
5346 		}
5347 		if (rsm == NULL) {
5348 			counter_u64_add(rack_tlp_does_nada, 1);
5349 #ifdef TCP_BLACKBOX
5350 			tcp_log_dump_tp_logbuf(tp, "nada counter trips", M_NOWAIT, true);
5351 #endif
5352 			goto out;
5353 		}
5354 	} else {
5355 		/*
5356 		 * We must find the last segment
5357 		 * that was acceptable by the client.
5358 		 */
5359 		RB_FOREACH_REVERSE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
5360 			if ((rsm->r_flags & RACK_RWND_COLLAPSED) == 0) {
5361 				/* Found one */
5362 				break;
5363 			}
5364 		}
5365 		if (rsm == NULL) {
5366 			/* None? if so send the first */
5367 			rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
5368 			if (rsm == NULL) {
5369 				counter_u64_add(rack_tlp_does_nada, 1);
5370 #ifdef TCP_BLACKBOX
5371 				tcp_log_dump_tp_logbuf(tp, "nada counter trips", M_NOWAIT, true);
5372 #endif
5373 				goto out;
5374 			}
5375 		}
5376 	}
5377 	if ((rsm->r_end - rsm->r_start) > ctf_fixed_maxseg(tp)) {
5378 		/*
5379 		 * We need to split this the last segment in two.
5380 		 */
5381 		struct rack_sendmap *nrsm;
5382 
5383 
5384 		nrsm = rack_alloc_full_limit(rack);
5385 		if (nrsm == NULL) {
5386 			/*
5387 			 * No memory to split, we will just exit and punt
5388 			 * off to the RXT timer.
5389 			 */
5390 			counter_u64_add(rack_tlp_does_nada, 1);
5391 			goto out;
5392 		}
5393 		rack_clone_rsm(rack, nrsm, rsm,
5394 			       (rsm->r_end - ctf_fixed_maxseg(tp)));
5395 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
5396 #ifdef INVARIANTS
5397 		if (insret != NULL) {
5398 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
5399 			      nrsm, insret, rack, rsm);
5400 		}
5401 #endif
5402 		if (rsm->r_in_tmap) {
5403 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
5404 			nrsm->r_in_tmap = 1;
5405 		}
5406 		rsm->r_flags &= (~RACK_HAS_FIN);
5407 		rsm = nrsm;
5408 	}
5409 	rack->r_ctl.rc_tlpsend = rsm;
5410 send:
5411 	rack->r_timer_override = 1;
5412 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP;
5413 	return (0);
5414 out:
5415 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP;
5416 	return (0);
5417 }
5418 
5419 /*
5420  * Delayed ack Timer, here we simply need to setup the
5421  * ACK_NOW flag and remove the DELACK flag. From there
5422  * the output routine will send the ack out.
5423  *
5424  * We only return 1, saying don't proceed, if all timers
5425  * are stopped (destroyed PCB?).
5426  */
5427 static int
5428 rack_timeout_delack(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5429 {
5430 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5431 		return (1);
5432 	}
5433 	rack_log_to_event(rack, RACK_TO_FRM_DELACK, NULL);
5434 	tp->t_flags &= ~TF_DELACK;
5435 	tp->t_flags |= TF_ACKNOW;
5436 	KMOD_TCPSTAT_INC(tcps_delack);
5437 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK;
5438 	return (0);
5439 }
5440 
5441 /*
5442  * Persists timer, here we simply send the
5443  * same thing as a keepalive will.
5444  * the one byte send.
5445  *
5446  * We only return 1, saying don't proceed, if all timers
5447  * are stopped (destroyed PCB?).
5448  */
5449 static int
5450 rack_timeout_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5451 {
5452 	struct tcptemp *t_template;
5453 	struct inpcb *inp;
5454 	int32_t retval = 1;
5455 
5456 	inp = tp->t_inpcb;
5457 
5458 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5459 		return (1);
5460 	}
5461 	if (rack->rc_in_persist == 0)
5462 		return (0);
5463 	if (ctf_progress_timeout_check(tp, false)) {
5464 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
5465 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
5466 		tcp_set_inp_to_drop(inp, ETIMEDOUT);
5467 		return (1);
5468 	}
5469 	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
5470 	/*
5471 	 * Persistence timer into zero window. Force a byte to be output, if
5472 	 * possible.
5473 	 */
5474 	KMOD_TCPSTAT_INC(tcps_persisttimeo);
5475 	/*
5476 	 * Hack: if the peer is dead/unreachable, we do not time out if the
5477 	 * window is closed.  After a full backoff, drop the connection if
5478 	 * the idle time (no responses to probes) reaches the maximum
5479 	 * backoff that we would use if retransmitting.
5480 	 */
5481 	if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
5482 	    (ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
5483 	    ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
5484 		KMOD_TCPSTAT_INC(tcps_persistdrop);
5485 		retval = 1;
5486 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
5487 		tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT);
5488 		goto out;
5489 	}
5490 	if ((sbavail(&rack->rc_inp->inp_socket->so_snd) == 0) &&
5491 	    tp->snd_una == tp->snd_max)
5492 		rack_exit_persist(tp, rack, cts);
5493 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_PERSIT;
5494 	/*
5495 	 * If the user has closed the socket then drop a persisting
5496 	 * connection after a much reduced timeout.
5497 	 */
5498 	if (tp->t_state > TCPS_CLOSE_WAIT &&
5499 	    (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) {
5500 		retval = 1;
5501 		KMOD_TCPSTAT_INC(tcps_persistdrop);
5502 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
5503 		tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT);
5504 		goto out;
5505 	}
5506 	t_template = tcpip_maketemplate(rack->rc_inp);
5507 	if (t_template) {
5508 		/* only set it if we were answered */
5509 		if (rack->forced_ack == 0) {
5510 			rack->forced_ack = 1;
5511 			rack->r_ctl.forced_ack_ts = tcp_get_usecs(NULL);
5512 		}
5513 		tcp_respond(tp, t_template->tt_ipgen,
5514 			    &t_template->tt_t, (struct mbuf *)NULL,
5515 			    tp->rcv_nxt, tp->snd_una - 1, 0);
5516 		/* This sends an ack */
5517 		if (tp->t_flags & TF_DELACK)
5518 			tp->t_flags &= ~TF_DELACK;
5519 		free(t_template, M_TEMP);
5520 	}
5521 	if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
5522 		tp->t_rxtshift++;
5523 out:
5524 	rack_log_to_event(rack, RACK_TO_FRM_PERSIST, NULL);
5525 	rack_start_hpts_timer(rack, tp, cts,
5526 			      0, 0, 0);
5527 	return (retval);
5528 }
5529 
5530 /*
5531  * If a keepalive goes off, we had no other timers
5532  * happening. We always return 1 here since this
5533  * routine either drops the connection or sends
5534  * out a segment with respond.
5535  */
5536 static int
5537 rack_timeout_keepalive(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5538 {
5539 	struct tcptemp *t_template;
5540 	struct inpcb *inp;
5541 
5542 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5543 		return (1);
5544 	}
5545 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_KEEP;
5546 	inp = tp->t_inpcb;
5547 	rack_log_to_event(rack, RACK_TO_FRM_KEEP, NULL);
5548 	/*
5549 	 * Keep-alive timer went off; send something or drop connection if
5550 	 * idle for too long.
5551 	 */
5552 	KMOD_TCPSTAT_INC(tcps_keeptimeo);
5553 	if (tp->t_state < TCPS_ESTABLISHED)
5554 		goto dropit;
5555 	if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
5556 	    tp->t_state <= TCPS_CLOSING) {
5557 		if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp))
5558 			goto dropit;
5559 		/*
5560 		 * Send a packet designed to force a response if the peer is
5561 		 * up and reachable: either an ACK if the connection is
5562 		 * still alive, or an RST if the peer has closed the
5563 		 * connection due to timeout or reboot. Using sequence
5564 		 * number tp->snd_una-1 causes the transmitted zero-length
5565 		 * segment to lie outside the receive window; by the
5566 		 * protocol spec, this requires the correspondent TCP to
5567 		 * respond.
5568 		 */
5569 		KMOD_TCPSTAT_INC(tcps_keepprobe);
5570 		t_template = tcpip_maketemplate(inp);
5571 		if (t_template) {
5572 			if (rack->forced_ack == 0) {
5573 				rack->forced_ack = 1;
5574 				rack->r_ctl.forced_ack_ts = tcp_get_usecs(NULL);
5575 			}
5576 			tcp_respond(tp, t_template->tt_ipgen,
5577 			    &t_template->tt_t, (struct mbuf *)NULL,
5578 			    tp->rcv_nxt, tp->snd_una - 1, 0);
5579 			free(t_template, M_TEMP);
5580 		}
5581 	}
5582 	rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
5583 	return (1);
5584 dropit:
5585 	KMOD_TCPSTAT_INC(tcps_keepdrops);
5586 	tcp_log_end_status(tp, TCP_EI_STATUS_KEEP_MAX);
5587 	tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT);
5588 	return (1);
5589 }
5590 
5591 /*
5592  * Retransmit helper function, clear up all the ack
5593  * flags and take care of important book keeping.
5594  */
5595 static void
5596 rack_remxt_tmr(struct tcpcb *tp)
5597 {
5598 	/*
5599 	 * The retransmit timer went off, all sack'd blocks must be
5600 	 * un-acked.
5601 	 */
5602 	struct rack_sendmap *rsm, *trsm = NULL;
5603 	struct tcp_rack *rack;
5604 	int32_t cnt = 0;
5605 
5606 	rack = (struct tcp_rack *)tp->t_fb_ptr;
5607 	rack_timer_cancel(tp, rack, tcp_ts_getticks(), __LINE__);
5608 	rack_log_to_event(rack, RACK_TO_FRM_TMR, NULL);
5609 	if (rack->r_state && (rack->r_state != tp->t_state))
5610 		rack_set_state(tp, rack);
5611 	/*
5612 	 * Ideally we would like to be able to
5613 	 * mark SACK-PASS on anything not acked here.
5614 	 * However, if we do that we would burst out
5615 	 * all that data 1ms apart. This would be unwise,
5616 	 * so for now we will just let the normal rxt timer
5617 	 * and tlp timer take care of it.
5618 	 */
5619 	RB_FOREACH(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
5620 		if (rsm->r_flags & RACK_ACKED) {
5621 			cnt++;
5622 			rsm->r_dupack = 0;
5623 			rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
5624 			if (rsm->r_in_tmap == 0) {
5625 				/* We must re-add it back to the tlist */
5626 				if (trsm == NULL) {
5627 					TAILQ_INSERT_HEAD(&rack->r_ctl.rc_tmap, rsm, r_tnext);
5628 				} else {
5629 					TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, trsm, rsm, r_tnext);
5630 				}
5631 				rsm->r_in_tmap = 1;
5632 			}
5633 		}
5634 		trsm = rsm;
5635 		if (rsm->r_flags & RACK_ACKED)
5636 			rsm->r_flags |= RACK_WAS_ACKED;
5637 		rsm->r_flags &= ~(RACK_ACKED | RACK_SACK_PASSED | RACK_WAS_SACKPASS);
5638 	}
5639 	/* Clear the count (we just un-acked them) */
5640 	rack->r_ctl.rc_sacked = 0;
5641 	rack->r_ctl.rc_agg_delayed = 0;
5642 	rack->r_early = 0;
5643 	rack->r_ctl.rc_agg_early = 0;
5644 	rack->r_late = 0;
5645 	/* Clear the tlp rtx mark */
5646 	rack->r_ctl.rc_resend = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
5647 	rack->r_ctl.rc_prr_sndcnt = 0;
5648 	rack_log_to_prr(rack, 6, 0);
5649 	rack->r_timer_override = 1;
5650 }
5651 
5652 static void
5653 rack_cc_conn_init(struct tcpcb *tp)
5654 {
5655 	struct tcp_rack *rack;
5656 
5657 
5658 	rack = (struct tcp_rack *)tp->t_fb_ptr;
5659 	cc_conn_init(tp);
5660 	/*
5661 	 * We want a chance to stay in slowstart as
5662 	 * we create a connection. TCP spec says that
5663 	 * initially ssthresh is infinite. For our
5664 	 * purposes that is the snd_wnd.
5665 	 */
5666 	if (tp->snd_ssthresh < tp->snd_wnd) {
5667 		tp->snd_ssthresh = tp->snd_wnd;
5668 	}
5669 	/*
5670 	 * We also want to assure a IW worth of
5671 	 * data can get inflight.
5672 	 */
5673 	if (rc_init_window(rack) < tp->snd_cwnd)
5674 		tp->snd_cwnd = rc_init_window(rack);
5675 }
5676 
5677 /*
5678  * Re-transmit timeout! If we drop the PCB we will return 1, otherwise
5679  * we will setup to retransmit the lowest seq number outstanding.
5680  */
5681 static int
5682 rack_timeout_rxt(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5683 {
5684 	int32_t rexmt;
5685 	struct inpcb *inp;
5686 	int32_t retval = 0;
5687 	bool isipv6;
5688 
5689 	inp = tp->t_inpcb;
5690 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5691 		return (1);
5692 	}
5693 	if (ctf_progress_timeout_check(tp, false)) {
5694 		tcp_log_end_status(tp, TCP_EI_STATUS_RETRAN);
5695 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
5696 		tcp_set_inp_to_drop(inp, ETIMEDOUT);
5697 		return (1);
5698 	}
5699 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_RXT;
5700 	if (TCPS_HAVEESTABLISHED(tp->t_state) &&
5701 	    (tp->snd_una == tp->snd_max)) {
5702 		/* Nothing outstanding .. nothing to do */
5703 		return (0);
5704 	}
5705 	/*
5706 	 * Retransmission timer went off.  Message has not been acked within
5707 	 * retransmit interval.  Back off to a longer retransmit interval
5708 	 * and retransmit one segment.
5709 	 */
5710 	rack_remxt_tmr(tp);
5711 	if ((rack->r_ctl.rc_resend == NULL) ||
5712 	    ((rack->r_ctl.rc_resend->r_flags & RACK_RWND_COLLAPSED) == 0)) {
5713 		/*
5714 		 * If the rwnd collapsed on
5715 		 * the one we are retransmitting
5716 		 * it does not count against the
5717 		 * rxt count.
5718 		 */
5719 		tp->t_rxtshift++;
5720 	}
5721 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT) {
5722 		tp->t_rxtshift = TCP_MAXRXTSHIFT;
5723 		KMOD_TCPSTAT_INC(tcps_timeoutdrop);
5724 		retval = 1;
5725 		tcp_log_end_status(tp, TCP_EI_STATUS_RETRAN);
5726 		tcp_set_inp_to_drop(rack->rc_inp,
5727 		    (tp->t_softerror ? (uint16_t) tp->t_softerror : ETIMEDOUT));
5728 		goto out;
5729 	}
5730 	if (tp->t_state == TCPS_SYN_SENT) {
5731 		/*
5732 		 * If the SYN was retransmitted, indicate CWND to be limited
5733 		 * to 1 segment in cc_conn_init().
5734 		 */
5735 		tp->snd_cwnd = 1;
5736 	} else if (tp->t_rxtshift == 1) {
5737 		/*
5738 		 * first retransmit; record ssthresh and cwnd so they can be
5739 		 * recovered if this turns out to be a "bad" retransmit. A
5740 		 * retransmit is considered "bad" if an ACK for this segment
5741 		 * is received within RTT/2 interval; the assumption here is
5742 		 * that the ACK was already in flight.  See "On Estimating
5743 		 * End-to-End Network Path Properties" by Allman and Paxson
5744 		 * for more details.
5745 		 */
5746 		tp->snd_cwnd_prev = tp->snd_cwnd;
5747 		tp->snd_ssthresh_prev = tp->snd_ssthresh;
5748 		tp->snd_recover_prev = tp->snd_recover;
5749 		if (IN_FASTRECOVERY(tp->t_flags))
5750 			tp->t_flags |= TF_WASFRECOVERY;
5751 		else
5752 			tp->t_flags &= ~TF_WASFRECOVERY;
5753 		if (IN_CONGRECOVERY(tp->t_flags))
5754 			tp->t_flags |= TF_WASCRECOVERY;
5755 		else
5756 			tp->t_flags &= ~TF_WASCRECOVERY;
5757 		tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
5758 		tp->t_flags |= TF_PREVVALID;
5759 	} else
5760 		tp->t_flags &= ~TF_PREVVALID;
5761 	KMOD_TCPSTAT_INC(tcps_rexmttimeo);
5762 	if ((tp->t_state == TCPS_SYN_SENT) ||
5763 	    (tp->t_state == TCPS_SYN_RECEIVED))
5764 		rexmt = MSEC_2_TICKS(RACK_INITIAL_RTO * tcp_backoff[tp->t_rxtshift]);
5765 	else
5766 		rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
5767 	TCPT_RANGESET(tp->t_rxtcur, rexmt,
5768 	   max(MSEC_2_TICKS(rack_rto_min), rexmt),
5769 	   MSEC_2_TICKS(rack_rto_max));
5770 	/*
5771 	 * We enter the path for PLMTUD if connection is established or, if
5772 	 * connection is FIN_WAIT_1 status, reason for the last is that if
5773 	 * amount of data we send is very small, we could send it in couple
5774 	 * of packets and process straight to FIN. In that case we won't
5775 	 * catch ESTABLISHED state.
5776 	 */
5777 #ifdef INET6
5778 	isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) ? true : false;
5779 #else
5780 	isipv6 = false;
5781 #endif
5782 	if (((V_tcp_pmtud_blackhole_detect == 1) ||
5783 	    (V_tcp_pmtud_blackhole_detect == 2 && !isipv6) ||
5784 	    (V_tcp_pmtud_blackhole_detect == 3 && isipv6)) &&
5785 	    ((tp->t_state == TCPS_ESTABLISHED) ||
5786 	    (tp->t_state == TCPS_FIN_WAIT_1))) {
5787 
5788 		/*
5789 		 * Idea here is that at each stage of mtu probe (usually,
5790 		 * 1448 -> 1188 -> 524) should be given 2 chances to recover
5791 		 * before further clamping down. 'tp->t_rxtshift % 2 == 0'
5792 		 * should take care of that.
5793 		 */
5794 		if (((tp->t_flags2 & (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) ==
5795 		    (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) &&
5796 		    (tp->t_rxtshift >= 2 && tp->t_rxtshift < 6 &&
5797 		    tp->t_rxtshift % 2 == 0)) {
5798 			/*
5799 			 * Enter Path MTU Black-hole Detection mechanism: -
5800 			 * Disable Path MTU Discovery (IP "DF" bit). -
5801 			 * Reduce MTU to lower value than what we negotiated
5802 			 * with peer.
5803 			 */
5804 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) == 0) {
5805 				/* Record that we may have found a black hole. */
5806 				tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE;
5807 				/* Keep track of previous MSS. */
5808 				tp->t_pmtud_saved_maxseg = tp->t_maxseg;
5809 			}
5810 
5811 			/*
5812 			 * Reduce the MSS to blackhole value or to the
5813 			 * default in an attempt to retransmit.
5814 			 */
5815 #ifdef INET6
5816 			if (isipv6 &&
5817 			    tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss) {
5818 				/* Use the sysctl tuneable blackhole MSS. */
5819 				tp->t_maxseg = V_tcp_v6pmtud_blackhole_mss;
5820 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
5821 			} else if (isipv6) {
5822 				/* Use the default MSS. */
5823 				tp->t_maxseg = V_tcp_v6mssdflt;
5824 				/*
5825 				 * Disable Path MTU Discovery when we switch
5826 				 * to minmss.
5827 				 */
5828 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
5829 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
5830 			}
5831 #endif
5832 #if defined(INET6) && defined(INET)
5833 			else
5834 #endif
5835 #ifdef INET
5836 			if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss) {
5837 				/* Use the sysctl tuneable blackhole MSS. */
5838 				tp->t_maxseg = V_tcp_pmtud_blackhole_mss;
5839 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
5840 			} else {
5841 				/* Use the default MSS. */
5842 				tp->t_maxseg = V_tcp_mssdflt;
5843 				/*
5844 				 * Disable Path MTU Discovery when we switch
5845 				 * to minmss.
5846 				 */
5847 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
5848 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
5849 			}
5850 #endif
5851 		} else {
5852 			/*
5853 			 * If further retransmissions are still unsuccessful
5854 			 * with a lowered MTU, maybe this isn't a blackhole
5855 			 * and we restore the previous MSS and blackhole
5856 			 * detection flags. The limit '6' is determined by
5857 			 * giving each probe stage (1448, 1188, 524) 2
5858 			 * chances to recover.
5859 			 */
5860 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) &&
5861 			    (tp->t_rxtshift >= 6)) {
5862 				tp->t_flags2 |= TF2_PLPMTU_PMTUD;
5863 				tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE;
5864 				tp->t_maxseg = tp->t_pmtud_saved_maxseg;
5865 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_failed);
5866 			}
5867 		}
5868 	}
5869 	/*
5870 	 * If we backed off this far, our srtt estimate is probably bogus.
5871 	 * Clobber it so we'll take the next rtt measurement as our srtt;
5872 	 * move the current srtt into rttvar to keep the current retransmit
5873 	 * times until then.
5874 	 */
5875 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
5876 #ifdef INET6
5877 		if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
5878 			in6_losing(tp->t_inpcb);
5879 		else
5880 #endif
5881 			in_losing(tp->t_inpcb);
5882 		tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
5883 		tp->t_srtt = 0;
5884 	}
5885 	sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
5886 	tp->snd_recover = tp->snd_max;
5887 	tp->t_flags |= TF_ACKNOW;
5888 	tp->t_rtttime = 0;
5889 	rack_cong_signal(tp, NULL, CC_RTO);
5890 out:
5891 	return (retval);
5892 }
5893 
5894 static int
5895 rack_process_timers(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, uint8_t hpts_calling)
5896 {
5897 	int32_t ret = 0;
5898 	int32_t timers = (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK);
5899 
5900 	if (timers == 0) {
5901 		return (0);
5902 	}
5903 	if (tp->t_state == TCPS_LISTEN) {
5904 		/* no timers on listen sockets */
5905 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)
5906 			return (0);
5907 		return (1);
5908 	}
5909 	if ((timers & PACE_TMR_RACK) &&
5910 	    rack->rc_on_min_to) {
5911 		/*
5912 		 * For the rack timer when we
5913 		 * are on a min-timeout (which means rrr_conf = 3)
5914 		 * we don't want to check the timer. It may
5915 		 * be going off for a pace and thats ok we
5916 		 * want to send the retransmit (if its ready).
5917 		 *
5918 		 * If its on a normal rack timer (non-min) then
5919 		 * we will check if its expired.
5920 		 */
5921 		goto skip_time_check;
5922 	}
5923 	if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) {
5924 		uint32_t left;
5925 
5926 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
5927 			ret = -1;
5928 			rack_log_to_processing(rack, cts, ret, 0);
5929 			return (0);
5930 		}
5931 		if (hpts_calling == 0) {
5932 			/*
5933 			 * A user send or queued mbuf (sack) has called us? We
5934 			 * return 0 and let the pacing guards
5935 			 * deal with it if they should or
5936 			 * should not cause a send.
5937 			 */
5938 			ret = -2;
5939 			rack_log_to_processing(rack, cts, ret, 0);
5940 			return (0);
5941 		}
5942 		/*
5943 		 * Ok our timer went off early and we are not paced false
5944 		 * alarm, go back to sleep.
5945 		 */
5946 		ret = -3;
5947 		left = rack->r_ctl.rc_timer_exp - cts;
5948 		tcp_hpts_insert(tp->t_inpcb, HPTS_MS_TO_SLOTS(left));
5949 		rack_log_to_processing(rack, cts, ret, left);
5950 		return (1);
5951 	}
5952 skip_time_check:
5953 	rack->rc_tmr_stopped = 0;
5954 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_MASK;
5955 	if (timers & PACE_TMR_DELACK) {
5956 		ret = rack_timeout_delack(tp, rack, cts);
5957 	} else if (timers & PACE_TMR_RACK) {
5958 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
5959 		ret = rack_timeout_rack(tp, rack, cts);
5960 	} else if (timers & PACE_TMR_TLP) {
5961 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
5962 		ret = rack_timeout_tlp(tp, rack, cts);
5963 	} else if (timers & PACE_TMR_RXT) {
5964 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
5965 		ret = rack_timeout_rxt(tp, rack, cts);
5966 	} else if (timers & PACE_TMR_PERSIT) {
5967 		ret = rack_timeout_persist(tp, rack, cts);
5968 	} else if (timers & PACE_TMR_KEEP) {
5969 		ret = rack_timeout_keepalive(tp, rack, cts);
5970 	}
5971 	rack_log_to_processing(rack, cts, ret, timers);
5972 	return (ret);
5973 }
5974 
5975 static void
5976 rack_timer_cancel(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int line)
5977 {
5978 	struct timeval tv;
5979 	uint32_t us_cts, flags_on_entry;
5980 	uint8_t hpts_removed = 0;
5981 
5982 
5983 	flags_on_entry = rack->r_ctl.rc_hpts_flags;
5984 	us_cts = tcp_get_usecs(&tv);
5985 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
5986 	    ((TSTMP_GEQ(us_cts, rack->r_ctl.rc_last_output_to)) ||
5987 	     ((tp->snd_max - tp->snd_una) == 0))) {
5988 		tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
5989 		hpts_removed = 1;
5990 		/* If we were not delayed cancel out the flag. */
5991 		if ((tp->snd_max - tp->snd_una) == 0)
5992 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
5993 		rack_log_to_cancel(rack, hpts_removed, line, us_cts, &tv, flags_on_entry);
5994 	}
5995 	if (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
5996 		rack->rc_tmr_stopped = rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
5997 		if (rack->rc_inp->inp_in_hpts &&
5998 		    ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0)) {
5999 			/*
6000 			 * Canceling timer's when we have no output being
6001 			 * paced. We also must remove ourselves from the
6002 			 * hpts.
6003 			 */
6004 			tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
6005 			hpts_removed = 1;
6006 		}
6007 		rack->r_ctl.rc_hpts_flags &= ~(PACE_TMR_MASK);
6008 	}
6009 	if (hpts_removed == 0)
6010 		rack_log_to_cancel(rack, hpts_removed, line, us_cts, &tv, flags_on_entry);
6011 }
6012 
6013 static void
6014 rack_timer_stop(struct tcpcb *tp, uint32_t timer_type)
6015 {
6016 	return;
6017 }
6018 
6019 static int
6020 rack_stopall(struct tcpcb *tp)
6021 {
6022 	struct tcp_rack *rack;
6023 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6024 	rack->t_timers_stopped = 1;
6025 	return (0);
6026 }
6027 
6028 static void
6029 rack_timer_activate(struct tcpcb *tp, uint32_t timer_type, uint32_t delta)
6030 {
6031 	return;
6032 }
6033 
6034 static int
6035 rack_timer_active(struct tcpcb *tp, uint32_t timer_type)
6036 {
6037 	return (0);
6038 }
6039 
6040 static void
6041 rack_stop_all_timers(struct tcpcb *tp)
6042 {
6043 	struct tcp_rack *rack;
6044 
6045 	/*
6046 	 * Assure no timers are running.
6047 	 */
6048 	if (tcp_timer_active(tp, TT_PERSIST)) {
6049 		/* We enter in persists, set the flag appropriately */
6050 		rack = (struct tcp_rack *)tp->t_fb_ptr;
6051 		rack->rc_in_persist = 1;
6052 	}
6053 	tcp_timer_suspend(tp, TT_PERSIST);
6054 	tcp_timer_suspend(tp, TT_REXMT);
6055 	tcp_timer_suspend(tp, TT_KEEP);
6056 	tcp_timer_suspend(tp, TT_DELACK);
6057 }
6058 
6059 static void
6060 rack_update_rsm(struct tcpcb *tp, struct tcp_rack *rack,
6061     struct rack_sendmap *rsm, uint32_t ts)
6062 {
6063 	int32_t idx;
6064 
6065 	rsm->r_rtr_cnt++;
6066 	rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
6067 	rsm->r_dupack = 0;
6068 	if (rsm->r_rtr_cnt > RACK_NUM_OF_RETRANS) {
6069 		rsm->r_rtr_cnt = RACK_NUM_OF_RETRANS;
6070 		rsm->r_flags |= RACK_OVERMAX;
6071 	}
6072 	if ((rsm->r_rtr_cnt > 1) && ((rsm->r_flags & RACK_TLP) == 0)) {
6073 		rack->r_ctl.rc_holes_rxt += (rsm->r_end - rsm->r_start);
6074 		rsm->r_rtr_bytes += (rsm->r_end - rsm->r_start);
6075 	}
6076 	idx = rsm->r_rtr_cnt - 1;
6077 	rsm->r_tim_lastsent[idx] = ts;
6078 	if (rsm->r_flags & RACK_ACKED) {
6079 		/* Problably MTU discovery messing with us */
6080 		rsm->r_flags &= ~RACK_ACKED;
6081 		rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
6082 	}
6083 	if (rsm->r_in_tmap) {
6084 		TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
6085 		rsm->r_in_tmap = 0;
6086 	}
6087 	TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
6088 	rsm->r_in_tmap = 1;
6089 	if (rsm->r_flags & RACK_SACK_PASSED) {
6090 		/* We have retransmitted due to the SACK pass */
6091 		rsm->r_flags &= ~RACK_SACK_PASSED;
6092 		rsm->r_flags |= RACK_WAS_SACKPASS;
6093 	}
6094 }
6095 
6096 
6097 static uint32_t
6098 rack_update_entry(struct tcpcb *tp, struct tcp_rack *rack,
6099     struct rack_sendmap *rsm, uint32_t ts, int32_t *lenp)
6100 {
6101 	/*
6102 	 * We (re-)transmitted starting at rsm->r_start for some length
6103 	 * (possibly less than r_end.
6104 	 */
6105 	struct rack_sendmap *nrsm, *insret;
6106 	uint32_t c_end;
6107 	int32_t len;
6108 
6109 	len = *lenp;
6110 	c_end = rsm->r_start + len;
6111 	if (SEQ_GEQ(c_end, rsm->r_end)) {
6112 		/*
6113 		 * We retransmitted the whole piece or more than the whole
6114 		 * slopping into the next rsm.
6115 		 */
6116 		rack_update_rsm(tp, rack, rsm, ts);
6117 		if (c_end == rsm->r_end) {
6118 			*lenp = 0;
6119 			return (0);
6120 		} else {
6121 			int32_t act_len;
6122 
6123 			/* Hangs over the end return whats left */
6124 			act_len = rsm->r_end - rsm->r_start;
6125 			*lenp = (len - act_len);
6126 			return (rsm->r_end);
6127 		}
6128 		/* We don't get out of this block. */
6129 	}
6130 	/*
6131 	 * Here we retransmitted less than the whole thing which means we
6132 	 * have to split this into what was transmitted and what was not.
6133 	 */
6134 	nrsm = rack_alloc_full_limit(rack);
6135 	if (nrsm == NULL) {
6136 		/*
6137 		 * We can't get memory, so lets not proceed.
6138 		 */
6139 		*lenp = 0;
6140 		return (0);
6141 	}
6142 	/*
6143 	 * So here we are going to take the original rsm and make it what we
6144 	 * retransmitted. nrsm will be the tail portion we did not
6145 	 * retransmit. For example say the chunk was 1, 11 (10 bytes). And
6146 	 * we retransmitted 5 bytes i.e. 1, 5. The original piece shrinks to
6147 	 * 1, 6 and the new piece will be 6, 11.
6148 	 */
6149 	rack_clone_rsm(rack, nrsm, rsm, c_end);
6150 	nrsm->r_dupack = 0;
6151 	rack_log_retran_reason(rack, nrsm, __LINE__, 0, 2);
6152 	insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
6153 #ifdef INVARIANTS
6154 	if (insret != NULL) {
6155 		panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
6156 		      nrsm, insret, rack, rsm);
6157 	}
6158 #endif
6159 	if (rsm->r_in_tmap) {
6160 		TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
6161 		nrsm->r_in_tmap = 1;
6162 	}
6163 	rsm->r_flags &= (~RACK_HAS_FIN);
6164 	rack_update_rsm(tp, rack, rsm, ts);
6165 	*lenp = 0;
6166 	return (0);
6167 }
6168 
6169 
6170 static void
6171 rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len,
6172     uint32_t seq_out, uint8_t th_flags, int32_t err, uint32_t ts,
6173     uint8_t pass, struct rack_sendmap *hintrsm, uint32_t us_cts)
6174 {
6175 	struct tcp_rack *rack;
6176 	struct rack_sendmap *rsm, *nrsm, *insret, fe;
6177 	register uint32_t snd_max, snd_una;
6178 
6179 	/*
6180 	 * Add to the RACK log of packets in flight or retransmitted. If
6181 	 * there is a TS option we will use the TS echoed, if not we will
6182 	 * grab a TS.
6183 	 *
6184 	 * Retransmissions will increment the count and move the ts to its
6185 	 * proper place. Note that if options do not include TS's then we
6186 	 * won't be able to effectively use the ACK for an RTT on a retran.
6187 	 *
6188 	 * Notes about r_start and r_end. Lets consider a send starting at
6189 	 * sequence 1 for 10 bytes. In such an example the r_start would be
6190 	 * 1 (starting sequence) but the r_end would be r_start+len i.e. 11.
6191 	 * This means that r_end is actually the first sequence for the next
6192 	 * slot (11).
6193 	 *
6194 	 */
6195 	/*
6196 	 * If err is set what do we do XXXrrs? should we not add the thing?
6197 	 * -- i.e. return if err != 0 or should we pretend we sent it? --
6198 	 * i.e. proceed with add ** do this for now.
6199 	 */
6200 	INP_WLOCK_ASSERT(tp->t_inpcb);
6201 	if (err)
6202 		/*
6203 		 * We don't log errors -- we could but snd_max does not
6204 		 * advance in this case either.
6205 		 */
6206 		return;
6207 
6208 	if (th_flags & TH_RST) {
6209 		/*
6210 		 * We don't log resets and we return immediately from
6211 		 * sending
6212 		 */
6213 		return;
6214 	}
6215 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6216 	snd_una = tp->snd_una;
6217 	if (SEQ_LEQ((seq_out + len), snd_una)) {
6218 		/* Are sending an old segment to induce an ack (keep-alive)? */
6219 		return;
6220 	}
6221 	if (SEQ_LT(seq_out, snd_una)) {
6222 		/* huh? should we panic? */
6223 		uint32_t end;
6224 
6225 		end = seq_out + len;
6226 		seq_out = snd_una;
6227 		if (SEQ_GEQ(end, seq_out))
6228 			len = end - seq_out;
6229 		else
6230 			len = 0;
6231 	}
6232 	snd_max = tp->snd_max;
6233 	if (th_flags & (TH_SYN | TH_FIN)) {
6234 		/*
6235 		 * The call to rack_log_output is made before bumping
6236 		 * snd_max. This means we can record one extra byte on a SYN
6237 		 * or FIN if seq_out is adding more on and a FIN is present
6238 		 * (and we are not resending).
6239 		 */
6240 		if ((th_flags & TH_SYN) && (seq_out == tp->iss))
6241 			len++;
6242 		if (th_flags & TH_FIN)
6243 			len++;
6244 		if (SEQ_LT(snd_max, tp->snd_nxt)) {
6245 			/*
6246 			 * The add/update as not been done for the FIN/SYN
6247 			 * yet.
6248 			 */
6249 			snd_max = tp->snd_nxt;
6250 		}
6251 	}
6252 	if (len == 0) {
6253 		/* We don't log zero window probes */
6254 		return;
6255 	}
6256 	rack->r_ctl.rc_time_last_sent = ts;
6257 	if (IN_RECOVERY(tp->t_flags)) {
6258 		rack->r_ctl.rc_prr_out += len;
6259 	}
6260 	/* First question is it a retransmission or new? */
6261 	if (seq_out == snd_max) {
6262 		/* Its new */
6263 again:
6264 		rsm = rack_alloc(rack);
6265 		if (rsm == NULL) {
6266 			/*
6267 			 * Hmm out of memory and the tcb got destroyed while
6268 			 * we tried to wait.
6269 			 */
6270 			return;
6271 		}
6272 		if (th_flags & TH_FIN) {
6273 			rsm->r_flags = RACK_HAS_FIN;
6274 		} else {
6275 			rsm->r_flags = 0;
6276 		}
6277 		rsm->r_tim_lastsent[0] = ts;
6278 		rsm->r_rtr_cnt = 1;
6279 		rsm->r_rtr_bytes = 0;
6280 		rsm->usec_orig_send = us_cts;
6281 		if (th_flags & TH_SYN) {
6282 			/* The data space is one beyond snd_una */
6283 			rsm->r_flags |= RACK_HAS_SIN;
6284 			rsm->r_start = seq_out + 1;
6285 			rsm->r_end = rsm->r_start + (len - 1);
6286 		} else {
6287 			/* Normal case */
6288 			rsm->r_start = seq_out;
6289 			rsm->r_end = rsm->r_start + len;
6290 		}
6291 		rsm->r_dupack = 0;
6292 		rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
6293 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
6294 #ifdef INVARIANTS
6295 		if (insret != NULL) {
6296 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
6297 			      nrsm, insret, rack, rsm);
6298 		}
6299 #endif
6300 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
6301 		rsm->r_in_tmap = 1;
6302 		/*
6303 		 * Special case detection, is there just a single
6304 		 * packet outstanding when we are not in recovery?
6305 		 *
6306 		 * If this is true mark it so.
6307 		 */
6308 		if ((IN_RECOVERY(tp->t_flags) == 0) &&
6309 		    (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) == ctf_fixed_maxseg(tp))) {
6310 			struct rack_sendmap *prsm;
6311 
6312 			prsm = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
6313 			if (prsm)
6314 				prsm->r_one_out_nr = 1;
6315 		}
6316 		return;
6317 	}
6318 	/*
6319 	 * If we reach here its a retransmission and we need to find it.
6320 	 */
6321 	memset(&fe, 0, sizeof(fe));
6322 more:
6323 	if (hintrsm && (hintrsm->r_start == seq_out)) {
6324 		rsm = hintrsm;
6325 		hintrsm = NULL;
6326 	} else {
6327 		/* No hints sorry */
6328 		rsm = NULL;
6329 	}
6330 	if ((rsm) && (rsm->r_start == seq_out)) {
6331 		seq_out = rack_update_entry(tp, rack, rsm, ts, &len);
6332 		if (len == 0) {
6333 			return;
6334 		} else {
6335 			goto more;
6336 		}
6337 	}
6338 	/* Ok it was not the last pointer go through it the hard way. */
6339 refind:
6340 	fe.r_start = seq_out;
6341 	rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
6342 	if (rsm) {
6343 		if (rsm->r_start == seq_out) {
6344 			seq_out = rack_update_entry(tp, rack, rsm, ts, &len);
6345 			if (len == 0) {
6346 				return;
6347 			} else {
6348 				goto refind;
6349 			}
6350 		}
6351 		if (SEQ_GEQ(seq_out, rsm->r_start) && SEQ_LT(seq_out, rsm->r_end)) {
6352 			/* Transmitted within this piece */
6353 			/*
6354 			 * Ok we must split off the front and then let the
6355 			 * update do the rest
6356 			 */
6357 			nrsm = rack_alloc_full_limit(rack);
6358 			if (nrsm == NULL) {
6359 				rack_update_rsm(tp, rack, rsm, ts);
6360 				return;
6361 			}
6362 			/*
6363 			 * copy rsm to nrsm and then trim the front of rsm
6364 			 * to not include this part.
6365 			 */
6366 			rack_clone_rsm(rack, nrsm, rsm, seq_out);
6367 			insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
6368 #ifdef INVARIANTS
6369 			if (insret != NULL) {
6370 				panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
6371 				      nrsm, insret, rack, rsm);
6372 			}
6373 #endif
6374 			if (rsm->r_in_tmap) {
6375 				TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
6376 				nrsm->r_in_tmap = 1;
6377 			}
6378 			rsm->r_flags &= (~RACK_HAS_FIN);
6379 			seq_out = rack_update_entry(tp, rack, nrsm, ts, &len);
6380 			if (len == 0) {
6381 				return;
6382 			} else if (len > 0)
6383 				goto refind;
6384 		}
6385 	}
6386 	/*
6387 	 * Hmm not found in map did they retransmit both old and on into the
6388 	 * new?
6389 	 */
6390 	if (seq_out == tp->snd_max) {
6391 		goto again;
6392 	} else if (SEQ_LT(seq_out, tp->snd_max)) {
6393 #ifdef INVARIANTS
6394 		printf("seq_out:%u len:%d snd_una:%u snd_max:%u -- but rsm not found?\n",
6395 		    seq_out, len, tp->snd_una, tp->snd_max);
6396 		printf("Starting Dump of all rack entries\n");
6397 		RB_FOREACH(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
6398 			printf("rsm:%p start:%u end:%u\n",
6399 			    rsm, rsm->r_start, rsm->r_end);
6400 		}
6401 		printf("Dump complete\n");
6402 		panic("seq_out not found rack:%p tp:%p",
6403 		    rack, tp);
6404 #endif
6405 	} else {
6406 #ifdef INVARIANTS
6407 		/*
6408 		 * Hmm beyond sndmax? (only if we are using the new rtt-pack
6409 		 * flag)
6410 		 */
6411 		panic("seq_out:%u(%d) is beyond snd_max:%u tp:%p",
6412 		    seq_out, len, tp->snd_max, tp);
6413 #endif
6414 	}
6415 }
6416 
6417 /*
6418  * Record one of the RTT updates from an ack into
6419  * our sample structure.
6420  */
6421 
6422 static void
6423 tcp_rack_xmit_timer(struct tcp_rack *rack, int32_t rtt, uint32_t len, uint32_t us_rtt,
6424 		    int confidence, struct rack_sendmap *rsm, uint16_t rtrcnt)
6425 {
6426 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
6427 	    (rack->r_ctl.rack_rs.rs_rtt_lowest > rtt)) {
6428 		rack->r_ctl.rack_rs.rs_rtt_lowest = rtt;
6429 	}
6430 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
6431 	    (rack->r_ctl.rack_rs.rs_rtt_highest < rtt)) {
6432 		rack->r_ctl.rack_rs.rs_rtt_highest = rtt;
6433 	}
6434 	if (rack->rc_tp->t_flags & TF_GPUTINPROG) {
6435 	    if (us_rtt < rack->r_ctl.rc_gp_lowrtt)
6436 		rack->r_ctl.rc_gp_lowrtt = us_rtt;
6437 	    if (rack->rc_tp->snd_wnd > rack->r_ctl.rc_gp_high_rwnd)
6438 		    rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
6439 	}
6440 	if ((confidence == 1) &&
6441 	    ((rsm == NULL) ||
6442 	     (rsm->r_just_ret) ||
6443 	     (rsm->r_one_out_nr &&
6444 	      len < (ctf_fixed_maxseg(rack->rc_tp) * 2)))) {
6445 		/*
6446 		 * If the rsm had a just return
6447 		 * hit it then we can't trust the
6448 		 * rtt measurement for buffer deterimination
6449 		 * Note that a confidence of 2, indicates
6450 		 * SACK'd which overrides the r_just_ret or
6451 		 * the r_one_out_nr. If it was a CUM-ACK and
6452 		 * we had only two outstanding, but get an
6453 		 * ack for only 1. Then that also lowers our
6454 		 * confidence.
6455 		 */
6456 		confidence = 0;
6457 	}
6458 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
6459 	    (rack->r_ctl.rack_rs.rs_us_rtt > us_rtt)) {
6460 		if (rack->r_ctl.rack_rs.confidence == 0) {
6461 			/*
6462 			 * We take anything with no current confidence
6463 			 * saved.
6464 			 */
6465 			rack->r_ctl.rack_rs.rs_us_rtt = us_rtt;
6466 			rack->r_ctl.rack_rs.confidence = confidence;
6467 			rack->r_ctl.rack_rs.rs_us_rtrcnt = rtrcnt;
6468 		} else if (confidence || rack->r_ctl.rack_rs.confidence) {
6469 			/*
6470 			 * Once we have a confident number,
6471 			 * we can update it with a smaller
6472 			 * value since this confident number
6473 			 * may include the DSACK time until
6474 			 * the next segment (the second one) arrived.
6475 			 */
6476 			rack->r_ctl.rack_rs.rs_us_rtt = us_rtt;
6477 			rack->r_ctl.rack_rs.confidence = confidence;
6478 			rack->r_ctl.rack_rs.rs_us_rtrcnt = rtrcnt;
6479 		}
6480 
6481 	}
6482 	rack_log_rtt_upd(rack->rc_tp, rack, us_rtt, len, rsm, confidence);
6483 	rack->r_ctl.rack_rs.rs_flags = RACK_RTT_VALID;
6484 	rack->r_ctl.rack_rs.rs_rtt_tot += rtt;
6485 	rack->r_ctl.rack_rs.rs_rtt_cnt++;
6486 }
6487 
6488 /*
6489  * Collect new round-trip time estimate
6490  * and update averages and current timeout.
6491  */
6492 static void
6493 tcp_rack_xmit_timer_commit(struct tcp_rack *rack, struct tcpcb *tp)
6494 {
6495 	int32_t delta;
6496 	uint32_t o_srtt, o_var;
6497 	int32_t hrtt_up = 0;
6498 	int32_t rtt;
6499 
6500 	if (rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY)
6501 		/* No valid sample */
6502 		return;
6503 	if (rack->r_ctl.rc_rate_sample_method == USE_RTT_LOW) {
6504 		/* We are to use the lowest RTT seen in a single ack */
6505 		rtt = rack->r_ctl.rack_rs.rs_rtt_lowest;
6506 	} else if (rack->r_ctl.rc_rate_sample_method == USE_RTT_HIGH) {
6507 		/* We are to use the highest RTT seen in a single ack */
6508 		rtt = rack->r_ctl.rack_rs.rs_rtt_highest;
6509 	} else if (rack->r_ctl.rc_rate_sample_method == USE_RTT_AVG) {
6510 		/* We are to use the average RTT seen in a single ack */
6511 		rtt = (int32_t)(rack->r_ctl.rack_rs.rs_rtt_tot /
6512 				(uint64_t)rack->r_ctl.rack_rs.rs_rtt_cnt);
6513 	} else {
6514 #ifdef INVARIANTS
6515 		panic("Unknown rtt variant %d", rack->r_ctl.rc_rate_sample_method);
6516 #endif
6517 		return;
6518 	}
6519 	if (rtt == 0)
6520 		rtt = 1;
6521 	if (rack->rc_gp_rtt_set == 0) {
6522 		/*
6523 		 * With no RTT we have to accept
6524 		 * even one we are not confident of.
6525 		 */
6526 		rack->r_ctl.rc_gp_srtt = rack->r_ctl.rack_rs.rs_us_rtt;
6527 		rack->rc_gp_rtt_set = 1;
6528 	} else if (rack->r_ctl.rack_rs.confidence) {
6529 		/* update the running gp srtt */
6530 		rack->r_ctl.rc_gp_srtt -= (rack->r_ctl.rc_gp_srtt/8);
6531 		rack->r_ctl.rc_gp_srtt += rack->r_ctl.rack_rs.rs_us_rtt / 8;
6532 	}
6533 	if (rack->r_ctl.rack_rs.confidence) {
6534 		/*
6535 		 * record the low and high for highly buffered path computation,
6536 		 * we only do this if we are confident (not a retransmission).
6537 		 */
6538 		if (rack->r_ctl.rc_highest_us_rtt < rack->r_ctl.rack_rs.rs_us_rtt) {
6539 			rack->r_ctl.rc_highest_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
6540 			hrtt_up = 1;
6541 		}
6542 		if (rack->rc_highly_buffered == 0) {
6543 			/*
6544 			 * Currently once we declare a path has
6545 			 * highly buffered there is no going
6546 			 * back, which may be a problem...
6547 			 */
6548 			if ((rack->r_ctl.rc_highest_us_rtt / rack->r_ctl.rc_lowest_us_rtt) > rack_hbp_thresh) {
6549 				rack_log_rtt_shrinks(rack, rack->r_ctl.rack_rs.rs_us_rtt,
6550 						     rack->r_ctl.rc_highest_us_rtt,
6551 						     rack->r_ctl.rc_lowest_us_rtt,
6552 						     RACK_RTTS_SEEHBP);
6553 				rack->rc_highly_buffered = 1;
6554 			}
6555 		}
6556 	}
6557 	if ((rack->r_ctl.rack_rs.confidence) ||
6558 	    (rack->r_ctl.rack_rs.rs_us_rtrcnt == 1)) {
6559 		/*
6560 		 * If we are highly confident of it <or> it was
6561 		 * never retransmitted we accept it as the last us_rtt.
6562 		 */
6563 		rack->r_ctl.rc_last_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
6564 		/* The lowest rtt can be set if its was not retransmited */
6565 		if (rack->r_ctl.rc_lowest_us_rtt > rack->r_ctl.rack_rs.rs_us_rtt) {
6566 			rack->r_ctl.rc_lowest_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
6567 			if (rack->r_ctl.rc_lowest_us_rtt == 0)
6568 				rack->r_ctl.rc_lowest_us_rtt = 1;
6569 		}
6570 	}
6571 	rack_log_rtt_sample(rack, rtt);
6572 	o_srtt = tp->t_srtt;
6573 	o_var = tp->t_rttvar;
6574 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6575 	if (tp->t_srtt != 0) {
6576 		/*
6577 		 * srtt is stored as fixed point with 5 bits after the
6578 		 * binary point (i.e., scaled by 8).  The following magic is
6579 		 * equivalent to the smoothing algorithm in rfc793 with an
6580 		 * alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed point).
6581 		 * Adjust rtt to origin 0.
6582 		 */
6583 		delta = ((rtt - 1) << TCP_DELTA_SHIFT)
6584 		    - (tp->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT));
6585 
6586 		tp->t_srtt += delta;
6587 		if (tp->t_srtt <= 0)
6588 			tp->t_srtt = 1;
6589 
6590 		/*
6591 		 * We accumulate a smoothed rtt variance (actually, a
6592 		 * smoothed mean difference), then set the retransmit timer
6593 		 * to smoothed rtt + 4 times the smoothed variance. rttvar
6594 		 * is stored as fixed point with 4 bits after the binary
6595 		 * point (scaled by 16).  The following is equivalent to
6596 		 * rfc793 smoothing with an alpha of .75 (rttvar =
6597 		 * rttvar*3/4 + |delta| / 4).  This replaces rfc793's
6598 		 * wired-in beta.
6599 		 */
6600 		if (delta < 0)
6601 			delta = -delta;
6602 		delta -= tp->t_rttvar >> (TCP_RTTVAR_SHIFT - TCP_DELTA_SHIFT);
6603 		tp->t_rttvar += delta;
6604 		if (tp->t_rttvar <= 0)
6605 			tp->t_rttvar = 1;
6606 		if (tp->t_rttbest > tp->t_srtt + tp->t_rttvar)
6607 			tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
6608 	} else {
6609 		/*
6610 		 * No rtt measurement yet - use the unsmoothed rtt. Set the
6611 		 * variance to half the rtt (so our first retransmit happens
6612 		 * at 3*rtt).
6613 		 */
6614 		tp->t_srtt = rtt << TCP_RTT_SHIFT;
6615 		tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1);
6616 		tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
6617 	}
6618 	KMOD_TCPSTAT_INC(tcps_rttupdated);
6619 	tp->t_rttupdated++;
6620 #ifdef STATS
6621 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, rtt));
6622 #endif
6623 	tp->t_rxtshift = 0;
6624 
6625 	/*
6626 	 * the retransmit should happen at rtt + 4 * rttvar. Because of the
6627 	 * way we do the smoothing, srtt and rttvar will each average +1/2
6628 	 * tick of bias.  When we compute the retransmit timer, we want 1/2
6629 	 * tick of rounding and 1 extra tick because of +-1/2 tick
6630 	 * uncertainty in the firing of the timer.  The bias will give us
6631 	 * exactly the 1.5 tick we need.  But, because the bias is
6632 	 * statistical, we have to test that we don't drop below the minimum
6633 	 * feasible timer (which is 2 ticks).
6634 	 */
6635 	TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
6636 	   max(MSEC_2_TICKS(rack_rto_min), rtt + 2), MSEC_2_TICKS(rack_rto_max));
6637 	tp->t_softerror = 0;
6638 }
6639 
6640 static void
6641 rack_earlier_retran(struct tcpcb *tp, struct rack_sendmap *rsm,
6642     uint32_t t, uint32_t cts)
6643 {
6644 	/*
6645 	 * For this RSM, we acknowledged the data from a previous
6646 	 * transmission, not the last one we made. This means we did a false
6647 	 * retransmit.
6648 	 */
6649 	struct tcp_rack *rack;
6650 
6651 	if (rsm->r_flags & RACK_HAS_FIN) {
6652 		/*
6653 		 * The sending of the FIN often is multiple sent when we
6654 		 * have everything outstanding ack'd. We ignore this case
6655 		 * since its over now.
6656 		 */
6657 		return;
6658 	}
6659 	if (rsm->r_flags & RACK_TLP) {
6660 		/*
6661 		 * We expect TLP's to have this occur.
6662 		 */
6663 		return;
6664 	}
6665 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6666 	/* should we undo cc changes and exit recovery? */
6667 	if (IN_RECOVERY(tp->t_flags)) {
6668 		if (rack->r_ctl.rc_rsm_start == rsm->r_start) {
6669 			/*
6670 			 * Undo what we ratched down and exit recovery if
6671 			 * possible
6672 			 */
6673 			EXIT_RECOVERY(tp->t_flags);
6674 			tp->snd_recover = tp->snd_una;
6675 			if (rack->r_ctl.rc_cwnd_at > tp->snd_cwnd)
6676 				tp->snd_cwnd = rack->r_ctl.rc_cwnd_at;
6677 			if (rack->r_ctl.rc_ssthresh_at > tp->snd_ssthresh)
6678 				tp->snd_ssthresh = rack->r_ctl.rc_ssthresh_at;
6679 		}
6680 	}
6681 	if (rsm->r_flags & RACK_WAS_SACKPASS) {
6682 		/*
6683 		 * We retransmitted based on a sack and the earlier
6684 		 * retransmission ack'd it - re-ordering is occuring.
6685 		 */
6686 		counter_u64_add(rack_reorder_seen, 1);
6687 		rack->r_ctl.rc_reorder_ts = cts;
6688 	}
6689 	counter_u64_add(rack_badfr, 1);
6690 	counter_u64_add(rack_badfr_bytes, (rsm->r_end - rsm->r_start));
6691 }
6692 
6693 static void
6694 rack_apply_updated_usrtt(struct tcp_rack *rack, uint32_t us_rtt, uint32_t us_cts)
6695 {
6696 	/*
6697 	 * Apply to filter the inbound us-rtt at us_cts.
6698 	 */
6699 	uint32_t old_rtt;
6700 
6701 	old_rtt = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
6702 	apply_filter_min_small(&rack->r_ctl.rc_gp_min_rtt,
6703 			       us_rtt, us_cts);
6704 	if (rack->r_ctl.last_pacing_time &&
6705 	    rack->rc_gp_dyn_mul &&
6706 	    (rack->r_ctl.last_pacing_time > us_rtt))
6707 		rack->pacing_longer_than_rtt = 1;
6708 	else
6709 		rack->pacing_longer_than_rtt = 0;
6710 	if (old_rtt > us_rtt) {
6711 		/* We just hit a new lower rtt time */
6712 		rack_log_rtt_shrinks(rack,  us_cts,  old_rtt,
6713 				     __LINE__, RACK_RTTS_NEWRTT);
6714 		/*
6715 		 * Only count it if its lower than what we saw within our
6716 		 * calculated range.
6717 		 */
6718 		if ((old_rtt - us_rtt) > rack_min_rtt_movement) {
6719 			if (rack_probertt_lower_within &&
6720 			    rack->rc_gp_dyn_mul &&
6721 			    (rack->use_fixed_rate == 0) &&
6722 			    (rack->rc_always_pace)) {
6723 				/*
6724 				 * We are seeing a new lower rtt very close
6725 				 * to the time that we would have entered probe-rtt.
6726 				 * This is probably due to the fact that a peer flow
6727 				 * has entered probe-rtt. Lets go in now too.
6728 				 */
6729 				uint32_t val;
6730 
6731 				val = rack_probertt_lower_within * rack_time_between_probertt;
6732 				val /= 100;
6733 				if ((rack->in_probe_rtt == 0)  &&
6734 				    ((us_cts - rack->r_ctl.rc_lower_rtt_us_cts) >= (rack_time_between_probertt - val)))	{
6735 					rack_enter_probertt(rack, us_cts);
6736 				}
6737 			}
6738 			rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
6739 		}
6740 	}
6741 }
6742 
6743 static int
6744 rack_update_rtt(struct tcpcb *tp, struct tcp_rack *rack,
6745     struct rack_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type, tcp_seq th_ack)
6746 {
6747 	int32_t i;
6748 	uint32_t t, len_acked;
6749 
6750 	if ((rsm->r_flags & RACK_ACKED) ||
6751 	    (rsm->r_flags & RACK_WAS_ACKED))
6752 		/* Already done */
6753 		return (0);
6754 
6755 	if (ack_type == CUM_ACKED) {
6756 		if (SEQ_GT(th_ack, rsm->r_end))
6757 			len_acked = rsm->r_end - rsm->r_start;
6758 		else
6759 			len_acked = th_ack - rsm->r_start;
6760 	} else
6761 		len_acked = rsm->r_end - rsm->r_start;
6762 	if (rsm->r_rtr_cnt == 1) {
6763 		uint32_t us_rtt;
6764 
6765 		t = cts - rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
6766 		if ((int)t <= 0)
6767 			t = 1;
6768 		if (!tp->t_rttlow || tp->t_rttlow > t)
6769 			tp->t_rttlow = t;
6770 		if (!rack->r_ctl.rc_rack_min_rtt ||
6771 		    SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
6772 			rack->r_ctl.rc_rack_min_rtt = t;
6773 			if (rack->r_ctl.rc_rack_min_rtt == 0) {
6774 				rack->r_ctl.rc_rack_min_rtt = 1;
6775 			}
6776 		}
6777 		us_rtt = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time) - rsm->usec_orig_send;
6778 		if (us_rtt == 0)
6779 			us_rtt = 1;
6780 		rack_apply_updated_usrtt(rack, us_rtt, tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time));
6781 		if (ack_type == SACKED)
6782 			tcp_rack_xmit_timer(rack, t + 1, len_acked, us_rtt, 2 , rsm, rsm->r_rtr_cnt);
6783 		else {
6784 			/*
6785 			 * For cum-ack we are only confident if what
6786 			 * is being acked is included in a measurement.
6787 			 * Otherwise it could be an idle period that
6788 			 * includes Delayed-ack time.
6789 			 */
6790 			tcp_rack_xmit_timer(rack, t + 1, len_acked, us_rtt,
6791 					    (rack->app_limited_needs_set ? 0 : 1), rsm, rsm->r_rtr_cnt);
6792 		}
6793 		if ((rsm->r_flags & RACK_TLP) &&
6794 		    (!IN_RECOVERY(tp->t_flags))) {
6795 			/* Segment was a TLP and our retrans matched */
6796 			if (rack->r_ctl.rc_tlp_cwnd_reduce) {
6797 				rack->r_ctl.rc_rsm_start = tp->snd_max;
6798 				rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
6799 				rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
6800 				rack_cong_signal(tp, NULL, CC_NDUPACK);
6801 				/*
6802 				 * When we enter recovery we need to assure
6803 				 * we send one packet.
6804 				 */
6805 				if (rack->rack_no_prr == 0) {
6806 					rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
6807 					rack_log_to_prr(rack, 7, 0);
6808 				}
6809 			}
6810 		}
6811 		if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)])) {
6812 			/* New more recent rack_tmit_time */
6813 			rack->r_ctl.rc_rack_tmit_time = rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
6814 			rack->rc_rack_rtt = t;
6815 		}
6816 		return (1);
6817 	}
6818 	/*
6819 	 * We clear the soft/rxtshift since we got an ack.
6820 	 * There is no assurance we will call the commit() function
6821 	 * so we need to clear these to avoid incorrect handling.
6822 	 */
6823 	tp->t_rxtshift = 0;
6824 	tp->t_softerror = 0;
6825 	if ((to->to_flags & TOF_TS) &&
6826 	    (ack_type == CUM_ACKED) &&
6827 	    (to->to_tsecr) &&
6828 	    ((rsm->r_flags & RACK_OVERMAX) == 0)) {
6829 		/*
6830 		 * Now which timestamp does it match? In this block the ACK
6831 		 * must be coming from a previous transmission.
6832 		 */
6833 		for (i = 0; i < rsm->r_rtr_cnt; i++) {
6834 			if (rsm->r_tim_lastsent[i] == to->to_tsecr) {
6835 				t = cts - rsm->r_tim_lastsent[i];
6836 				if ((int)t <= 0)
6837 					t = 1;
6838 				if ((i + 1) < rsm->r_rtr_cnt) {
6839 					/* Likely */
6840 					rack_earlier_retran(tp, rsm, t, cts);
6841 				}
6842 				if (!tp->t_rttlow || tp->t_rttlow > t)
6843 					tp->t_rttlow = t;
6844 				if (!rack->r_ctl.rc_rack_min_rtt || SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
6845 					rack->r_ctl.rc_rack_min_rtt = t;
6846 					if (rack->r_ctl.rc_rack_min_rtt == 0) {
6847 						rack->r_ctl.rc_rack_min_rtt = 1;
6848 					}
6849 				}
6850 				if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time,
6851 				    rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)])) {
6852 					/* New more recent rack_tmit_time */
6853 					rack->r_ctl.rc_rack_tmit_time = rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
6854 					rack->rc_rack_rtt = t;
6855 				}
6856 				tcp_rack_xmit_timer(rack, t + 1, len_acked, (t * HPTS_USEC_IN_MSEC), 0, rsm,
6857 						    rsm->r_rtr_cnt);
6858 				return (1);
6859 			}
6860 		}
6861 		goto ts_not_found;
6862 	} else {
6863 		/*
6864 		 * Ok its a SACK block that we retransmitted. or a windows
6865 		 * machine without timestamps. We can tell nothing from the
6866 		 * time-stamp since its not there or the time the peer last
6867 		 * recieved a segment that moved forward its cum-ack point.
6868 		 */
6869 ts_not_found:
6870 		i = rsm->r_rtr_cnt - 1;
6871 		t = cts - rsm->r_tim_lastsent[i];
6872 		if ((int)t <= 0)
6873 			t = 1;
6874 		if (rack->r_ctl.rc_rack_min_rtt && SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
6875 			/*
6876 			 * We retransmitted and the ack came back in less
6877 			 * than the smallest rtt we have observed. We most
6878 			 * likey did an improper retransmit as outlined in
6879 			 * 4.2 Step 3 point 2 in the rack-draft.
6880 			 */
6881 			i = rsm->r_rtr_cnt - 2;
6882 			t = cts - rsm->r_tim_lastsent[i];
6883 			rack_earlier_retran(tp, rsm, t, cts);
6884 		} else if (rack->r_ctl.rc_rack_min_rtt) {
6885 			/*
6886 			 * We retransmitted it and the retransmit did the
6887 			 * job.
6888 			 */
6889 			if (!rack->r_ctl.rc_rack_min_rtt ||
6890 			    SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
6891 				rack->r_ctl.rc_rack_min_rtt = t;
6892 				if (rack->r_ctl.rc_rack_min_rtt == 0) {
6893 					rack->r_ctl.rc_rack_min_rtt = 1;
6894 				}
6895 			}
6896 			if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, rsm->r_tim_lastsent[i])) {
6897 				/* New more recent rack_tmit_time */
6898 				rack->r_ctl.rc_rack_tmit_time = rsm->r_tim_lastsent[i];
6899 				rack->rc_rack_rtt = t;
6900 			}
6901 			return (1);
6902 		}
6903 	}
6904 	return (0);
6905 }
6906 
6907 /*
6908  * Mark the SACK_PASSED flag on all entries prior to rsm send wise.
6909  */
6910 static void
6911 rack_log_sack_passed(struct tcpcb *tp,
6912     struct tcp_rack *rack, struct rack_sendmap *rsm)
6913 {
6914 	struct rack_sendmap *nrsm;
6915 
6916 	nrsm = rsm;
6917 	TAILQ_FOREACH_REVERSE_FROM(nrsm, &rack->r_ctl.rc_tmap,
6918 	    rack_head, r_tnext) {
6919 		if (nrsm == rsm) {
6920 			/* Skip orginal segment he is acked */
6921 			continue;
6922 		}
6923 		if (nrsm->r_flags & RACK_ACKED) {
6924 			/*
6925 			 * Skip ack'd segments, though we
6926 			 * should not see these, since tmap
6927 			 * should not have ack'd segments.
6928 			 */
6929 			continue;
6930 		}
6931 		if (nrsm->r_flags & RACK_SACK_PASSED) {
6932 			/*
6933 			 * We found one that is already marked
6934 			 * passed, we have been here before and
6935 			 * so all others below this are marked.
6936 			 */
6937 			break;
6938 		}
6939 		nrsm->r_flags |= RACK_SACK_PASSED;
6940 		nrsm->r_flags &= ~RACK_WAS_SACKPASS;
6941 	}
6942 }
6943 
6944 static void
6945 rack_need_set_test(struct tcpcb *tp,
6946 		   struct tcp_rack *rack,
6947 		   struct rack_sendmap *rsm,
6948 		   tcp_seq th_ack,
6949 		   int line,
6950 		   int use_which)
6951 {
6952 
6953 	if ((tp->t_flags & TF_GPUTINPROG) &&
6954 	    SEQ_GEQ(rsm->r_end, tp->gput_seq)) {
6955 		/*
6956 		 * We were app limited, and this ack
6957 		 * butts up or goes beyond the point where we want
6958 		 * to start our next measurement. We need
6959 		 * to record the new gput_ts as here and
6960 		 * possibly update the start sequence.
6961 		 */
6962 		uint32_t seq, ts;
6963 
6964 		if (rsm->r_rtr_cnt > 1) {
6965 			/*
6966 			 * This is a retransmit, can we
6967 			 * really make any assessment at this
6968 			 * point?  We are not really sure of
6969 			 * the timestamp, is it this or the
6970 			 * previous transmission?
6971 			 *
6972 			 * Lets wait for something better that
6973 			 * is not retransmitted.
6974 			 */
6975 			return;
6976 		}
6977 		seq = tp->gput_seq;
6978 		ts = tp->gput_ts;
6979 		rack->app_limited_needs_set = 0;
6980 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
6981 		/* Do we start at a new end? */
6982 		if ((use_which == RACK_USE_BEG) &&
6983 		    SEQ_GEQ(rsm->r_start, tp->gput_seq)) {
6984 			/*
6985 			 * When we get an ACK that just eats
6986 			 * up some of the rsm, we set RACK_USE_BEG
6987 			 * since whats at r_start (i.e. th_ack)
6988 			 * is left unacked and thats where the
6989 			 * measurement not starts.
6990 			 */
6991 			tp->gput_seq = rsm->r_start;
6992 			rack->r_ctl.rc_gp_output_ts = rsm->usec_orig_send;
6993 		}
6994 		if ((use_which == RACK_USE_END) &&
6995 		    SEQ_GEQ(rsm->r_end, tp->gput_seq)) {
6996 			    /*
6997 			     * We use the end when the cumack
6998 			     * is moving forward and completely
6999 			     * deleting the rsm passed so basically
7000 			     * r_end holds th_ack.
7001 			     *
7002 			     * For SACK's we also want to use the end
7003 			     * since this piece just got sacked and
7004 			     * we want to target anything after that
7005 			     * in our measurement.
7006 			     */
7007 			    tp->gput_seq = rsm->r_end;
7008 			    rack->r_ctl.rc_gp_output_ts = rsm->usec_orig_send;
7009 		}
7010 		if (use_which == RACK_USE_END_OR_THACK) {
7011 			/*
7012 			 * special case for ack moving forward,
7013 			 * not a sack, we need to move all the
7014 			 * way up to where this ack cum-ack moves
7015 			 * to.
7016 			 */
7017 			if (SEQ_GT(th_ack, rsm->r_end))
7018 				tp->gput_seq = th_ack;
7019 			else
7020 				tp->gput_seq = rsm->r_end;
7021 			rack->r_ctl.rc_gp_output_ts = rsm->usec_orig_send;
7022 		}
7023 		if (SEQ_GT(tp->gput_seq, tp->gput_ack)) {
7024 			/*
7025 			 * We moved beyond this guy's range, re-calculate
7026 			 * the new end point.
7027 			 */
7028 			if (rack->rc_gp_filled == 0) {
7029 				tp->gput_ack = tp->gput_seq + max(rc_init_window(rack), (MIN_GP_WIN * ctf_fixed_maxseg(tp)));
7030 			} else {
7031 				tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
7032 			}
7033 		}
7034 		/*
7035 		 * We are moving the goal post, we may be able to clear the
7036 		 * measure_saw_probe_rtt flag.
7037 		 */
7038 		if ((rack->in_probe_rtt == 0) &&
7039 		    (rack->measure_saw_probe_rtt) &&
7040 		    (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
7041 			rack->measure_saw_probe_rtt = 0;
7042 		rack_log_pacing_delay_calc(rack, ts, tp->gput_ts,
7043 					   seq, tp->gput_seq, 0, 5, line, NULL);
7044 		if (rack->rc_gp_filled &&
7045 		    ((tp->gput_ack - tp->gput_seq) <
7046 		     max(rc_init_window(rack), (MIN_GP_WIN *
7047 						ctf_fixed_maxseg(tp))))) {
7048 			/*
7049 			 * There is no sense of continuing this measurement
7050 			 * because its too small to gain us anything we
7051 			 * trust. Skip it and that way we can start a new
7052 			 * measurement quicker.
7053 			 */
7054 			rack_log_pacing_delay_calc(rack, tp->gput_ack, tp->gput_seq,
7055 						   0, 0, 0, 6, __LINE__, NULL);
7056 			tp->t_flags &= ~TF_GPUTINPROG;
7057 		}
7058 	}
7059 }
7060 
7061 static uint32_t
7062 rack_proc_sack_blk(struct tcpcb *tp, struct tcp_rack *rack, struct sackblk *sack,
7063 		   struct tcpopt *to, struct rack_sendmap **prsm, uint32_t cts, int *moved_two)
7064 {
7065 	uint32_t start, end, changed = 0;
7066 	struct rack_sendmap stack_map;
7067 	struct rack_sendmap *rsm, *nrsm, fe, *insret, *prev, *next;
7068 	int32_t used_ref = 1;
7069 	int moved = 0;
7070 
7071 	start = sack->start;
7072 	end = sack->end;
7073 	rsm = *prsm;
7074 	memset(&fe, 0, sizeof(fe));
7075 do_rest_ofb:
7076 	if ((rsm == NULL) ||
7077 	    (SEQ_LT(end, rsm->r_start)) ||
7078 	    (SEQ_GEQ(start, rsm->r_end)) ||
7079 	    (SEQ_LT(start, rsm->r_start))) {
7080 		/*
7081 		 * We are not in the right spot,
7082 		 * find the correct spot in the tree.
7083 		 */
7084 		used_ref = 0;
7085 		fe.r_start = start;
7086 		rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
7087 		moved++;
7088 	}
7089 	if (rsm == NULL) {
7090 		/* TSNH */
7091 		goto out;
7092 	}
7093 	/* Ok we have an ACK for some piece of this rsm */
7094 	if (rsm->r_start != start) {
7095 		if ((rsm->r_flags & RACK_ACKED) == 0) {
7096 			/**
7097 			 * Need to split this in two pieces the before and after,
7098 			 * the before remains in the map, the after must be
7099 			 * added. In other words we have:
7100 			 * rsm        |--------------|
7101 			 * sackblk        |------->
7102 			 * rsm will become
7103 			 *     rsm    |---|
7104 			 * and nrsm will be  the sacked piece
7105 			 *     nrsm       |----------|
7106 			 *
7107 			 * But before we start down that path lets
7108 			 * see if the sack spans over on top of
7109 			 * the next guy and it is already sacked.
7110 			 */
7111 			next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7112 			if (next && (next->r_flags & RACK_ACKED) &&
7113 			    SEQ_GEQ(end, next->r_start)) {
7114 				/**
7115 				 * So the next one is already acked, and
7116 				 * we can thus by hookery use our stack_map
7117 				 * to reflect the piece being sacked and
7118 				 * then adjust the two tree entries moving
7119 				 * the start and ends around. So we start like:
7120 				 *  rsm     |------------|             (not-acked)
7121 				 *  next                 |-----------| (acked)
7122 				 *  sackblk        |-------->
7123 				 *  We want to end like so:
7124 				 *  rsm     |------|                   (not-acked)
7125 				 *  next           |-----------------| (acked)
7126 				 *  nrsm           |-----|
7127 				 * Where nrsm is a temporary stack piece we
7128 				 * use to update all the gizmos.
7129 				 */
7130 				/* Copy up our fudge block */
7131 				nrsm = &stack_map;
7132 				memcpy(nrsm, rsm, sizeof(struct rack_sendmap));
7133 				/* Now adjust our tree blocks */
7134 				rsm->r_end = start;
7135 				next->r_start = start;
7136 				/* Clear out the dup ack count of the remainder */
7137 				rsm->r_dupack = 0;
7138 				rsm->r_just_ret = 0;
7139 				rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
7140 				/* Now lets make sure our fudge block is right */
7141 				nrsm->r_start = start;
7142 				/* Now lets update all the stats and such */
7143 				rack_update_rtt(tp, rack, nrsm, to, cts, SACKED, 0);
7144 				if (rack->app_limited_needs_set)
7145 					rack_need_set_test(tp, rack, nrsm, tp->snd_una, __LINE__, RACK_USE_END);
7146 				changed += (nrsm->r_end - nrsm->r_start);
7147 				rack->r_ctl.rc_sacked += (nrsm->r_end - nrsm->r_start);
7148 				if (nrsm->r_flags & RACK_SACK_PASSED) {
7149 					counter_u64_add(rack_reorder_seen, 1);
7150 					rack->r_ctl.rc_reorder_ts = cts;
7151 				}
7152 				/*
7153 				 * Now we want to go up from rsm (the
7154 				 * one left un-acked) to the next one
7155 				 * in the tmap. We do this so when
7156 				 * we walk backwards we include marking
7157 				 * sack-passed on rsm (The one passed in
7158 				 * is skipped since it is generally called
7159 				 * on something sacked before removing it
7160 				 * from the tmap).
7161 				 */
7162 				if (rsm->r_in_tmap) {
7163 					nrsm = TAILQ_NEXT(rsm, r_tnext);
7164 					/*
7165 					 * Now that we have the next
7166 					 * one walk backwards from there.
7167 					 */
7168 					if (nrsm && nrsm->r_in_tmap)
7169 						rack_log_sack_passed(tp, rack, nrsm);
7170 				}
7171 				/* Now are we done? */
7172 				if (SEQ_LT(end, next->r_end) ||
7173 				    (end == next->r_end)) {
7174 					/* Done with block */
7175 					goto out;
7176 				}
7177 				counter_u64_add(rack_sack_used_next_merge, 1);
7178 				/* Postion for the next block */
7179 				start = next->r_end;
7180 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, next);
7181 				if (rsm == NULL)
7182 					goto out;
7183 			} else {
7184 				/**
7185 				 * We can't use any hookery here, so we
7186 				 * need to split the map. We enter like
7187 				 * so:
7188 				 *  rsm      |--------|
7189 				 *  sackblk       |----->
7190 				 * We will add the new block nrsm and
7191 				 * that will be the new portion, and then
7192 				 * fall through after reseting rsm. So we
7193 				 * split and look like this:
7194 				 *  rsm      |----|
7195 				 *  sackblk       |----->
7196 				 *  nrsm          |---|
7197 				 * We then fall through reseting
7198 				 * rsm to nrsm, so the next block
7199 				 * picks it up.
7200 				 */
7201 				nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
7202 				if (nrsm == NULL) {
7203 					/*
7204 					 * failed XXXrrs what can we do but loose the sack
7205 					 * info?
7206 					 */
7207 					goto out;
7208 				}
7209 				counter_u64_add(rack_sack_splits, 1);
7210 				rack_clone_rsm(rack, nrsm, rsm, start);
7211 				rsm->r_just_ret = 0;
7212 				insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
7213 #ifdef INVARIANTS
7214 				if (insret != NULL) {
7215 					panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
7216 					      nrsm, insret, rack, rsm);
7217 				}
7218 #endif
7219 				if (rsm->r_in_tmap) {
7220 					TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7221 					nrsm->r_in_tmap = 1;
7222 				}
7223 				rsm->r_flags &= (~RACK_HAS_FIN);
7224 				/* Position us to point to the new nrsm that starts the sack blk */
7225 				rsm = nrsm;
7226 			}
7227 		} else {
7228 			/* Already sacked this piece */
7229 			counter_u64_add(rack_sack_skipped_acked, 1);
7230 			moved++;
7231 			if (end == rsm->r_end) {
7232 				/* Done with block */
7233 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7234 				goto out;
7235 			} else if (SEQ_LT(end, rsm->r_end)) {
7236 				/* A partial sack to a already sacked block */
7237 				moved++;
7238 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7239 				goto out;
7240 			} else {
7241 				/*
7242 				 * The end goes beyond this guy
7243 				 * repostion the start to the
7244 				 * next block.
7245 				 */
7246 				start = rsm->r_end;
7247 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7248 				if (rsm == NULL)
7249 					goto out;
7250 			}
7251 		}
7252 	}
7253 	if (SEQ_GEQ(end, rsm->r_end)) {
7254 		/**
7255 		 * The end of this block is either beyond this guy or right
7256 		 * at this guy. I.e.:
7257 		 *  rsm ---                 |-----|
7258 		 *  end                     |-----|
7259 		 *  <or>
7260 		 *  end                     |---------|
7261 		 */
7262 		if ((rsm->r_flags & RACK_ACKED) == 0) {
7263 			rack_update_rtt(tp, rack, rsm, to, cts, SACKED, 0);
7264 			changed += (rsm->r_end - rsm->r_start);
7265 			rack->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
7266 			if (rsm->r_in_tmap) /* should be true */
7267 				rack_log_sack_passed(tp, rack, rsm);
7268 			/* Is Reordering occuring? */
7269 			if (rsm->r_flags & RACK_SACK_PASSED) {
7270 				rsm->r_flags &= ~RACK_SACK_PASSED;
7271 				counter_u64_add(rack_reorder_seen, 1);
7272 				rack->r_ctl.rc_reorder_ts = cts;
7273 			}
7274 			if (rack->app_limited_needs_set)
7275 				rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_END);
7276 			rsm->r_ack_arrival = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
7277 			rsm->r_flags |= RACK_ACKED;
7278 			rsm->r_flags &= ~RACK_TLP;
7279 			if (rsm->r_in_tmap) {
7280 				TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7281 				rsm->r_in_tmap = 0;
7282 			}
7283 		} else {
7284 			counter_u64_add(rack_sack_skipped_acked, 1);
7285 			moved++;
7286 		}
7287 		if (end == rsm->r_end) {
7288 			/* This block only - done, setup for next  */
7289 			goto out;
7290 		}
7291 		/*
7292 		 * There is more not coverend by this rsm move on
7293 		 * to the next block in the RB tree.
7294 		 */
7295 		nrsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7296 		start = rsm->r_end;
7297 		rsm = nrsm;
7298 		if (rsm == NULL)
7299 			goto out;
7300 		goto do_rest_ofb;
7301 	}
7302 	/**
7303 	 * The end of this sack block is smaller than
7304 	 * our rsm i.e.:
7305 	 *  rsm ---                 |-----|
7306 	 *  end                     |--|
7307 	 */
7308 	if ((rsm->r_flags & RACK_ACKED) == 0) {
7309 		prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7310 		if (prev && (prev->r_flags & RACK_ACKED)) {
7311 			/**
7312 			 * Goal, we want the right remainder of rsm to shrink
7313 			 * in place and span from (rsm->r_start = end) to rsm->r_end.
7314 			 * We want to expand prev to go all the way
7315 			 * to prev->r_end <- end.
7316 			 * so in the tree we have before:
7317 			 *   prev     |--------|         (acked)
7318 			 *   rsm               |-------| (non-acked)
7319 			 *   sackblk           |-|
7320 			 * We churn it so we end up with
7321 			 *   prev     |----------|       (acked)
7322 			 *   rsm                 |-----| (non-acked)
7323 			 *   nrsm              |-| (temporary)
7324 			 */
7325 			nrsm = &stack_map;
7326 			memcpy(nrsm, rsm, sizeof(struct rack_sendmap));
7327 			prev->r_end = end;
7328 			rsm->r_start = end;
7329 			/* Now adjust nrsm (stack copy) to be
7330 			 * the one that is the small
7331 			 * piece that was "sacked".
7332 			 */
7333 			nrsm->r_end = end;
7334 			rsm->r_dupack = 0;
7335 			rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
7336 			/*
7337 			 * Now nrsm is our new little piece
7338 			 * that is acked (which was merged
7339 			 * to prev). Update the rtt and changed
7340 			 * based on that. Also check for reordering.
7341 			 */
7342 			rack_update_rtt(tp, rack, nrsm, to, cts, SACKED, 0);
7343 			if (rack->app_limited_needs_set)
7344 				rack_need_set_test(tp, rack, nrsm, tp->snd_una, __LINE__, RACK_USE_END);
7345 			changed += (nrsm->r_end - nrsm->r_start);
7346 			rack->r_ctl.rc_sacked += (nrsm->r_end - nrsm->r_start);
7347 			if (nrsm->r_flags & RACK_SACK_PASSED) {
7348 				counter_u64_add(rack_reorder_seen, 1);
7349 				rack->r_ctl.rc_reorder_ts = cts;
7350 			}
7351 			rsm = prev;
7352 			counter_u64_add(rack_sack_used_prev_merge, 1);
7353 		} else {
7354 			/**
7355 			 * This is the case where our previous
7356 			 * block is not acked either, so we must
7357 			 * split the block in two.
7358 			 */
7359 			nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
7360 			if (nrsm == NULL) {
7361 				/* failed rrs what can we do but loose the sack info? */
7362 				goto out;
7363 			}
7364 			/**
7365 			 * In this case nrsm becomes
7366 			 * nrsm->r_start = end;
7367 			 * nrsm->r_end = rsm->r_end;
7368 			 * which is un-acked.
7369 			 * <and>
7370 			 * rsm->r_end = nrsm->r_start;
7371 			 * i.e. the remaining un-acked
7372 			 * piece is left on the left
7373 			 * hand side.
7374 			 *
7375 			 * So we start like this
7376 			 * rsm      |----------| (not acked)
7377 			 * sackblk  |---|
7378 			 * build it so we have
7379 			 * rsm      |---|         (acked)
7380 			 * nrsm         |------|  (not acked)
7381 			 */
7382 			counter_u64_add(rack_sack_splits, 1);
7383 			rack_clone_rsm(rack, nrsm, rsm, end);
7384 			rsm->r_flags &= (~RACK_HAS_FIN);
7385 			rsm->r_just_ret = 0;
7386 			insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
7387 #ifdef INVARIANTS
7388 			if (insret != NULL) {
7389 				panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
7390 				      nrsm, insret, rack, rsm);
7391 			}
7392 #endif
7393 			if (rsm->r_in_tmap) {
7394 				TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7395 				nrsm->r_in_tmap = 1;
7396 			}
7397 			nrsm->r_dupack = 0;
7398 			rack_log_retran_reason(rack, nrsm, __LINE__, 0, 2);
7399 			rack_update_rtt(tp, rack, rsm, to, cts, SACKED, 0);
7400 			changed += (rsm->r_end - rsm->r_start);
7401 			rack->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
7402 			if (rsm->r_in_tmap) /* should be true */
7403 				rack_log_sack_passed(tp, rack, rsm);
7404 			/* Is Reordering occuring? */
7405 			if (rsm->r_flags & RACK_SACK_PASSED) {
7406 				rsm->r_flags &= ~RACK_SACK_PASSED;
7407 				counter_u64_add(rack_reorder_seen, 1);
7408 				rack->r_ctl.rc_reorder_ts = cts;
7409 			}
7410 			if (rack->app_limited_needs_set)
7411 				rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_END);
7412 			rsm->r_ack_arrival = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
7413 			rsm->r_flags |= RACK_ACKED;
7414 			rsm->r_flags &= ~RACK_TLP;
7415 			if (rsm->r_in_tmap) {
7416 				TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7417 				rsm->r_in_tmap = 0;
7418 			}
7419 		}
7420 	} else if (start != end){
7421 		/*
7422 		 * The block was already acked.
7423 		 */
7424 		counter_u64_add(rack_sack_skipped_acked, 1);
7425 		moved++;
7426 	}
7427 out:
7428 	if (rsm && (rsm->r_flags & RACK_ACKED)) {
7429 		/*
7430 		 * Now can we merge where we worked
7431 		 * with either the previous or
7432 		 * next block?
7433 		 */
7434 		next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7435 		while (next) {
7436 		    if (next->r_flags & RACK_ACKED) {
7437 			/* yep this and next can be merged */
7438 			rsm = rack_merge_rsm(rack, rsm, next);
7439 			next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7440 		    } else
7441 			    break;
7442 		}
7443 		/* Now what about the previous? */
7444 		prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7445 		while (prev) {
7446 		    if (prev->r_flags & RACK_ACKED) {
7447 			/* yep the previous and this can be merged */
7448 			rsm = rack_merge_rsm(rack, prev, rsm);
7449 			prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7450 		    } else
7451 			    break;
7452 		}
7453 	}
7454 	if (used_ref == 0) {
7455 		counter_u64_add(rack_sack_proc_all, 1);
7456 	} else {
7457 		counter_u64_add(rack_sack_proc_short, 1);
7458 	}
7459 	/* Save off the next one for quick reference. */
7460 	if (rsm)
7461 		nrsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7462 	else
7463 		nrsm = NULL;
7464 	*prsm = rack->r_ctl.rc_sacklast = nrsm;
7465 	/* Pass back the moved. */
7466 	*moved_two = moved;
7467 	return (changed);
7468 }
7469 
7470 static void inline
7471 rack_peer_reneges(struct tcp_rack *rack, struct rack_sendmap *rsm, tcp_seq th_ack)
7472 {
7473 	struct rack_sendmap *tmap;
7474 
7475 	tmap = NULL;
7476 	while (rsm && (rsm->r_flags & RACK_ACKED)) {
7477 		/* Its no longer sacked, mark it so */
7478 		rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
7479 #ifdef INVARIANTS
7480 		if (rsm->r_in_tmap) {
7481 			panic("rack:%p rsm:%p flags:0x%x in tmap?",
7482 			      rack, rsm, rsm->r_flags);
7483 		}
7484 #endif
7485 		rsm->r_flags &= ~(RACK_ACKED|RACK_SACK_PASSED|RACK_WAS_SACKPASS);
7486 		/* Rebuild it into our tmap */
7487 		if (tmap == NULL) {
7488 			TAILQ_INSERT_HEAD(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7489 			tmap = rsm;
7490 		} else {
7491 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, tmap, rsm, r_tnext);
7492 			tmap = rsm;
7493 		}
7494 		tmap->r_in_tmap = 1;
7495 		rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7496 	}
7497 	/*
7498 	 * Now lets possibly clear the sack filter so we start
7499 	 * recognizing sacks that cover this area.
7500 	 */
7501 	sack_filter_clear(&rack->r_ctl.rack_sf, th_ack);
7502 
7503 }
7504 
7505 static void
7506 rack_do_decay(struct tcp_rack *rack)
7507 {
7508 	struct timeval res;
7509 
7510 #define	timersub(tvp, uvp, vvp)						\
7511 	do {								\
7512 		(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec;		\
7513 		(vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec;	\
7514 		if ((vvp)->tv_usec < 0) {				\
7515 			(vvp)->tv_sec--;				\
7516 			(vvp)->tv_usec += 1000000;			\
7517 		}							\
7518 	} while (0)
7519 
7520 	timersub(&rack->r_ctl.act_rcv_time, &rack->r_ctl.rc_last_time_decay, &res);
7521 #undef timersub
7522 
7523 	rack->r_ctl.input_pkt++;
7524 	if ((rack->rc_in_persist) ||
7525 	    (res.tv_sec >= 1) ||
7526 	    (rack->rc_tp->snd_max == rack->rc_tp->snd_una)) {
7527 		/*
7528 		 * Check for decay of non-SAD,
7529 		 * we want all SAD detection metrics to
7530 		 * decay 1/4 per second (or more) passed.
7531 		 */
7532 		uint32_t pkt_delta;
7533 
7534 		pkt_delta = rack->r_ctl.input_pkt - rack->r_ctl.saved_input_pkt;
7535 		/* Update our saved tracking values */
7536 		rack->r_ctl.saved_input_pkt = rack->r_ctl.input_pkt;
7537 		rack->r_ctl.rc_last_time_decay = rack->r_ctl.act_rcv_time;
7538 		/* Now do we escape without decay? */
7539 #ifdef NETFLIX_EXP_DETECTION
7540 		if (rack->rc_in_persist ||
7541 		    (rack->rc_tp->snd_max == rack->rc_tp->snd_una) ||
7542 		    (pkt_delta < tcp_sad_low_pps)){
7543 			/*
7544 			 * We don't decay idle connections
7545 			 * or ones that have a low input pps.
7546 			 */
7547 			return;
7548 		}
7549 		/* Decay the counters */
7550 		rack->r_ctl.ack_count = ctf_decay_count(rack->r_ctl.ack_count,
7551 							tcp_sad_decay_val);
7552 		rack->r_ctl.sack_count = ctf_decay_count(rack->r_ctl.sack_count,
7553 							 tcp_sad_decay_val);
7554 		rack->r_ctl.sack_moved_extra = ctf_decay_count(rack->r_ctl.sack_moved_extra,
7555 							       tcp_sad_decay_val);
7556 		rack->r_ctl.sack_noextra_move = ctf_decay_count(rack->r_ctl.sack_noextra_move,
7557 								tcp_sad_decay_val);
7558 #endif
7559 	}
7560 }
7561 
7562 static void
7563 rack_log_ack(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th)
7564 {
7565 	uint32_t changed, entered_recovery = 0;
7566 	struct tcp_rack *rack;
7567 	struct rack_sendmap *rsm, *rm;
7568 	struct sackblk sack, sack_blocks[TCP_MAX_SACK + 1];
7569 	register uint32_t th_ack;
7570 	int32_t i, j, k, num_sack_blks = 0;
7571 	uint32_t cts, acked, ack_point, sack_changed = 0;
7572 	int loop_start = 0, moved_two = 0;
7573 	uint32_t tsused;
7574 
7575 
7576 	INP_WLOCK_ASSERT(tp->t_inpcb);
7577 	if (th->th_flags & TH_RST) {
7578 		/* We don't log resets */
7579 		return;
7580 	}
7581 	rack = (struct tcp_rack *)tp->t_fb_ptr;
7582 	cts = tcp_ts_getticks();
7583 	rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
7584 	changed = 0;
7585 	th_ack = th->th_ack;
7586 	if (rack->sack_attack_disable == 0)
7587 		rack_do_decay(rack);
7588 	if (BYTES_THIS_ACK(tp, th) >= ctf_fixed_maxseg(rack->rc_tp)) {
7589 		/*
7590 		 * You only get credit for
7591 		 * MSS and greater (and you get extra
7592 		 * credit for larger cum-ack moves).
7593 		 */
7594 		int ac;
7595 
7596 		ac = BYTES_THIS_ACK(tp, th) / ctf_fixed_maxseg(rack->rc_tp);
7597 		rack->r_ctl.ack_count += ac;
7598 		counter_u64_add(rack_ack_total, ac);
7599 	}
7600 	if (rack->r_ctl.ack_count > 0xfff00000) {
7601 		/*
7602 		 * reduce the number to keep us under
7603 		 * a uint32_t.
7604 		 */
7605 		rack->r_ctl.ack_count /= 2;
7606 		rack->r_ctl.sack_count /= 2;
7607 	}
7608 	if (SEQ_GT(th_ack, tp->snd_una)) {
7609 		rack_log_progress_event(rack, tp, ticks, PROGRESS_UPDATE, __LINE__);
7610 		tp->t_acktime = ticks;
7611 	}
7612 	if (rsm && SEQ_GT(th_ack, rsm->r_start))
7613 		changed = th_ack - rsm->r_start;
7614 	if (changed) {
7615 		/*
7616 		 * The ACK point is advancing to th_ack, we must drop off
7617 		 * the packets in the rack log and calculate any eligble
7618 		 * RTT's.
7619 		 */
7620 		rack->r_wanted_output = 1;
7621 more:
7622 		rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
7623 		if (rsm == NULL) {
7624 			if ((th_ack - 1) == tp->iss) {
7625 				/*
7626 				 * For the SYN incoming case we will not
7627 				 * have called tcp_output for the sending of
7628 				 * the SYN, so there will be no map. All
7629 				 * other cases should probably be a panic.
7630 				 */
7631 				goto proc_sack;
7632 			}
7633 			if (tp->t_flags & TF_SENTFIN) {
7634 				/* if we send a FIN we will not hav a map */
7635 				goto proc_sack;
7636 			}
7637 #ifdef INVARIANTS
7638 			panic("No rack map tp:%p for th:%p state:%d rack:%p snd_una:%u snd_max:%u snd_nxt:%u chg:%d\n",
7639 			      tp,
7640 			      th, tp->t_state, rack,
7641 			      tp->snd_una, tp->snd_max, tp->snd_nxt, changed);
7642 #endif
7643 			goto proc_sack;
7644 		}
7645 		if (SEQ_LT(th_ack, rsm->r_start)) {
7646 			/* Huh map is missing this */
7647 #ifdef INVARIANTS
7648 			printf("Rack map starts at r_start:%u for th_ack:%u huh? ts:%d rs:%d\n",
7649 			       rsm->r_start,
7650 			       th_ack, tp->t_state, rack->r_state);
7651 #endif
7652 			goto proc_sack;
7653 		}
7654 		rack_update_rtt(tp, rack, rsm, to, cts, CUM_ACKED, th_ack);
7655 		/* Now do we consume the whole thing? */
7656 		if (SEQ_GEQ(th_ack, rsm->r_end)) {
7657 			/* Its all consumed. */
7658 			uint32_t left;
7659 			uint8_t newly_acked;
7660 
7661 			rack->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes;
7662 			rsm->r_rtr_bytes = 0;
7663 			/* Record the time of highest cumack sent */
7664 			rack->r_ctl.rc_gp_cumack_ts = rsm->usec_orig_send;
7665 			rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7666 #ifdef INVARIANTS
7667 			if (rm != rsm) {
7668 				panic("removing head in rack:%p rsm:%p rm:%p",
7669 				      rack, rsm, rm);
7670 			}
7671 #endif
7672 			if (rsm->r_in_tmap) {
7673 				TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7674 				rsm->r_in_tmap = 0;
7675 			}
7676 			newly_acked = 1;
7677 			if (rsm->r_flags & RACK_ACKED) {
7678 				/*
7679 				 * It was acked on the scoreboard -- remove
7680 				 * it from total
7681 				 */
7682 				rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
7683 				newly_acked = 0;
7684 			} else if (rsm->r_flags & RACK_SACK_PASSED) {
7685 				/*
7686 				 * There are segments ACKED on the
7687 				 * scoreboard further up. We are seeing
7688 				 * reordering.
7689 				 */
7690 				rsm->r_flags &= ~RACK_SACK_PASSED;
7691 				counter_u64_add(rack_reorder_seen, 1);
7692 				rsm->r_ack_arrival = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
7693 				rsm->r_flags |= RACK_ACKED;
7694 				rack->r_ctl.rc_reorder_ts = cts;
7695 			}
7696 			left = th_ack - rsm->r_end;
7697 			if (rack->app_limited_needs_set && newly_acked)
7698 				rack_need_set_test(tp, rack, rsm, th_ack, __LINE__, RACK_USE_END_OR_THACK);
7699 			/* Free back to zone */
7700 			rack_free(rack, rsm);
7701 			if (left) {
7702 				goto more;
7703 			}
7704 			goto proc_sack;
7705 		}
7706 		if (rsm->r_flags & RACK_ACKED) {
7707 			/*
7708 			 * It was acked on the scoreboard -- remove it from
7709 			 * total for the part being cum-acked.
7710 			 */
7711 			rack->r_ctl.rc_sacked -= (th_ack - rsm->r_start);
7712 		}
7713 		/*
7714 		 * Clear the dup ack count for
7715 		 * the piece that remains.
7716 		 */
7717 		rsm->r_dupack = 0;
7718 		rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
7719 		if (rsm->r_rtr_bytes) {
7720 			/*
7721 			 * It was retransmitted adjust the
7722 			 * sack holes for what was acked.
7723 			 */
7724 			int ack_am;
7725 
7726 			ack_am = (th_ack - rsm->r_start);
7727 			if (ack_am >= rsm->r_rtr_bytes) {
7728 				rack->r_ctl.rc_holes_rxt -= ack_am;
7729 				rsm->r_rtr_bytes -= ack_am;
7730 			}
7731 		}
7732 		/*
7733 		 * Update where the piece starts and record
7734 		 * the time of send of highest cumack sent.
7735 		 */
7736 		rack->r_ctl.rc_gp_cumack_ts = rsm->usec_orig_send;
7737 		rsm->r_start = th_ack;
7738 		if (rack->app_limited_needs_set)
7739 			rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_BEG);
7740 
7741 	}
7742 proc_sack:
7743 	/* Check for reneging */
7744 	rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
7745 	if (rsm && (rsm->r_flags & RACK_ACKED) && (th_ack == rsm->r_start)) {
7746 		/*
7747 		 * The peer has moved snd_una up to
7748 		 * the edge of this send, i.e. one
7749 		 * that it had previously acked. The only
7750 		 * way that can be true if the peer threw
7751 		 * away data (space issues) that it had
7752 		 * previously sacked (else it would have
7753 		 * given us snd_una up to (rsm->r_end).
7754 		 * We need to undo the acked markings here.
7755 		 *
7756 		 * Note we have to look to make sure th_ack is
7757 		 * our rsm->r_start in case we get an old ack
7758 		 * where th_ack is behind snd_una.
7759 		 */
7760 		rack_peer_reneges(rack, rsm, th->th_ack);
7761 	}
7762 	if ((to->to_flags & TOF_SACK) == 0) {
7763 		/* We are done nothing left */
7764 		goto out;
7765 	}
7766 	/* Sack block processing */
7767 	if (SEQ_GT(th_ack, tp->snd_una))
7768 		ack_point = th_ack;
7769 	else
7770 		ack_point = tp->snd_una;
7771 	for (i = 0; i < to->to_nsacks; i++) {
7772 		bcopy((to->to_sacks + i * TCPOLEN_SACK),
7773 		      &sack, sizeof(sack));
7774 		sack.start = ntohl(sack.start);
7775 		sack.end = ntohl(sack.end);
7776 		if (SEQ_GT(sack.end, sack.start) &&
7777 		    SEQ_GT(sack.start, ack_point) &&
7778 		    SEQ_LT(sack.start, tp->snd_max) &&
7779 		    SEQ_GT(sack.end, ack_point) &&
7780 		    SEQ_LEQ(sack.end, tp->snd_max)) {
7781 			sack_blocks[num_sack_blks] = sack;
7782 			num_sack_blks++;
7783 #ifdef NETFLIX_STATS
7784 		} else if (SEQ_LEQ(sack.start, th_ack) &&
7785 			   SEQ_LEQ(sack.end, th_ack)) {
7786 			/*
7787 			 * Its a D-SACK block.
7788 			 */
7789 			tcp_record_dsack(sack.start, sack.end);
7790 #endif
7791 		}
7792 
7793 	}
7794 	/*
7795 	 * Sort the SACK blocks so we can update the rack scoreboard with
7796 	 * just one pass.
7797 	 */
7798 	num_sack_blks = sack_filter_blks(&rack->r_ctl.rack_sf, sack_blocks,
7799 					 num_sack_blks, th->th_ack);
7800 	ctf_log_sack_filter(rack->rc_tp, num_sack_blks, sack_blocks);
7801 	if (num_sack_blks == 0)  {
7802 		/* Nothing to sack (DSACKs?) */
7803 		goto out_with_totals;
7804 	}
7805 	if (num_sack_blks < 2) {
7806 		/* Only one, we don't need to sort */
7807 		goto do_sack_work;
7808 	}
7809 	/* Sort the sacks */
7810 	for (i = 0; i < num_sack_blks; i++) {
7811 		for (j = i + 1; j < num_sack_blks; j++) {
7812 			if (SEQ_GT(sack_blocks[i].end, sack_blocks[j].end)) {
7813 				sack = sack_blocks[i];
7814 				sack_blocks[i] = sack_blocks[j];
7815 				sack_blocks[j] = sack;
7816 			}
7817 		}
7818 	}
7819 	/*
7820 	 * Now are any of the sack block ends the same (yes some
7821 	 * implementations send these)?
7822 	 */
7823 again:
7824 	if (num_sack_blks == 0)
7825 		goto out_with_totals;
7826 	if (num_sack_blks > 1) {
7827 		for (i = 0; i < num_sack_blks; i++) {
7828 			for (j = i + 1; j < num_sack_blks; j++) {
7829 				if (sack_blocks[i].end == sack_blocks[j].end) {
7830 					/*
7831 					 * Ok these two have the same end we
7832 					 * want the smallest end and then
7833 					 * throw away the larger and start
7834 					 * again.
7835 					 */
7836 					if (SEQ_LT(sack_blocks[j].start, sack_blocks[i].start)) {
7837 						/*
7838 						 * The second block covers
7839 						 * more area use that
7840 						 */
7841 						sack_blocks[i].start = sack_blocks[j].start;
7842 					}
7843 					/*
7844 					 * Now collapse out the dup-sack and
7845 					 * lower the count
7846 					 */
7847 					for (k = (j + 1); k < num_sack_blks; k++) {
7848 						sack_blocks[j].start = sack_blocks[k].start;
7849 						sack_blocks[j].end = sack_blocks[k].end;
7850 						j++;
7851 					}
7852 					num_sack_blks--;
7853 					goto again;
7854 				}
7855 			}
7856 		}
7857 	}
7858 do_sack_work:
7859 	/*
7860 	 * First lets look to see if
7861 	 * we have retransmitted and
7862 	 * can use the transmit next?
7863 	 */
7864 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
7865 	if (rsm &&
7866 	    SEQ_GT(sack_blocks[0].end, rsm->r_start) &&
7867 	    SEQ_LT(sack_blocks[0].start, rsm->r_end)) {
7868 		/*
7869 		 * We probably did the FR and the next
7870 		 * SACK in continues as we would expect.
7871 		 */
7872 		acked = rack_proc_sack_blk(tp, rack, &sack_blocks[0], to, &rsm, cts, &moved_two);
7873 		if (acked) {
7874 			rack->r_wanted_output = 1;
7875 			changed += acked;
7876 			sack_changed += acked;
7877 		}
7878 		if (num_sack_blks == 1) {
7879 			/*
7880 			 * This is what we would expect from
7881 			 * a normal implementation to happen
7882 			 * after we have retransmitted the FR,
7883 			 * i.e the sack-filter pushes down
7884 			 * to 1 block and the next to be retransmitted
7885 			 * is the sequence in the sack block (has more
7886 			 * are acked). Count this as ACK'd data to boost
7887 			 * up the chances of recovering any false positives.
7888 			 */
7889 			rack->r_ctl.ack_count += (acked / ctf_fixed_maxseg(rack->rc_tp));
7890 			counter_u64_add(rack_ack_total, (acked / ctf_fixed_maxseg(rack->rc_tp)));
7891 			counter_u64_add(rack_express_sack, 1);
7892 			if (rack->r_ctl.ack_count > 0xfff00000) {
7893 				/*
7894 				 * reduce the number to keep us under
7895 				 * a uint32_t.
7896 				 */
7897 				rack->r_ctl.ack_count /= 2;
7898 				rack->r_ctl.sack_count /= 2;
7899 			}
7900 			goto out_with_totals;
7901 		} else {
7902 			/*
7903 			 * Start the loop through the
7904 			 * rest of blocks, past the first block.
7905 			 */
7906 			moved_two = 0;
7907 			loop_start = 1;
7908 		}
7909 	}
7910 	/* Its a sack of some sort */
7911 	rack->r_ctl.sack_count++;
7912 	if (rack->r_ctl.sack_count > 0xfff00000) {
7913 		/*
7914 		 * reduce the number to keep us under
7915 		 * a uint32_t.
7916 		 */
7917 		rack->r_ctl.ack_count /= 2;
7918 		rack->r_ctl.sack_count /= 2;
7919 	}
7920 	counter_u64_add(rack_sack_total, 1);
7921 	if (rack->sack_attack_disable) {
7922 		/* An attacker disablement is in place */
7923 		if (num_sack_blks > 1) {
7924 			rack->r_ctl.sack_count += (num_sack_blks - 1);
7925 			rack->r_ctl.sack_moved_extra++;
7926 			counter_u64_add(rack_move_some, 1);
7927 			if (rack->r_ctl.sack_moved_extra > 0xfff00000) {
7928 				rack->r_ctl.sack_moved_extra /= 2;
7929 				rack->r_ctl.sack_noextra_move /= 2;
7930 			}
7931 		}
7932 		goto out;
7933 	}
7934 	rsm = rack->r_ctl.rc_sacklast;
7935 	for (i = loop_start; i < num_sack_blks; i++) {
7936 		acked = rack_proc_sack_blk(tp, rack, &sack_blocks[i], to, &rsm, cts, &moved_two);
7937 		if (acked) {
7938 			rack->r_wanted_output = 1;
7939 			changed += acked;
7940 			sack_changed += acked;
7941 		}
7942 		if (moved_two) {
7943 			/*
7944 			 * If we did not get a SACK for at least a MSS and
7945 			 * had to move at all, or if we moved more than our
7946 			 * threshold, it counts against the "extra" move.
7947 			 */
7948 			rack->r_ctl.sack_moved_extra += moved_two;
7949 			counter_u64_add(rack_move_some, 1);
7950 		} else {
7951 			/*
7952 			 * else we did not have to move
7953 			 * any more than we would expect.
7954 			 */
7955 			rack->r_ctl.sack_noextra_move++;
7956 			counter_u64_add(rack_move_none, 1);
7957 		}
7958 		if (moved_two && (acked < ctf_fixed_maxseg(rack->rc_tp))) {
7959 			/*
7960 			 * If the SACK was not a full MSS then
7961 			 * we add to sack_count the number of
7962 			 * MSS's (or possibly more than
7963 			 * a MSS if its a TSO send) we had to skip by.
7964 			 */
7965 			rack->r_ctl.sack_count += moved_two;
7966 			counter_u64_add(rack_sack_total, moved_two);
7967 		}
7968 		/*
7969 		 * Now we need to setup for the next
7970 		 * round. First we make sure we won't
7971 		 * exceed the size of our uint32_t on
7972 		 * the various counts, and then clear out
7973 		 * moved_two.
7974 		 */
7975 		if ((rack->r_ctl.sack_moved_extra > 0xfff00000) ||
7976 		    (rack->r_ctl.sack_noextra_move > 0xfff00000)) {
7977 			rack->r_ctl.sack_moved_extra /= 2;
7978 			rack->r_ctl.sack_noextra_move /= 2;
7979 		}
7980 		if (rack->r_ctl.sack_count > 0xfff00000) {
7981 			rack->r_ctl.ack_count /= 2;
7982 			rack->r_ctl.sack_count /= 2;
7983 		}
7984 		moved_two = 0;
7985 	}
7986 out_with_totals:
7987 	if (num_sack_blks > 1) {
7988 		/*
7989 		 * You get an extra stroke if
7990 		 * you have more than one sack-blk, this
7991 		 * could be where we are skipping forward
7992 		 * and the sack-filter is still working, or
7993 		 * it could be an attacker constantly
7994 		 * moving us.
7995 		 */
7996 		rack->r_ctl.sack_moved_extra++;
7997 		counter_u64_add(rack_move_some, 1);
7998 	}
7999 out:
8000 #ifdef NETFLIX_EXP_DETECTION
8001 	if ((rack->do_detection || tcp_force_detection) &&
8002 	    tcp_sack_to_ack_thresh &&
8003 	    tcp_sack_to_move_thresh &&
8004 	    ((rack->r_ctl.rc_num_maps_alloced > tcp_map_minimum) || rack->sack_attack_disable)) {
8005 		/*
8006 		 * We have thresholds set to find
8007 		 * possible attackers and disable sack.
8008 		 * Check them.
8009 		 */
8010 		uint64_t ackratio, moveratio, movetotal;
8011 
8012 		/* Log detecting */
8013 		rack_log_sad(rack, 1);
8014 		ackratio = (uint64_t)(rack->r_ctl.sack_count);
8015 		ackratio *= (uint64_t)(1000);
8016 		if (rack->r_ctl.ack_count)
8017 			ackratio /= (uint64_t)(rack->r_ctl.ack_count);
8018 		else {
8019 			/* We really should not hit here */
8020 			ackratio = 1000;
8021 		}
8022 		if ((rack->sack_attack_disable  == 0) &&
8023 		    (ackratio > rack_highest_sack_thresh_seen))
8024 			rack_highest_sack_thresh_seen = (uint32_t)ackratio;
8025 		movetotal = rack->r_ctl.sack_moved_extra;
8026 		movetotal += rack->r_ctl.sack_noextra_move;
8027 		moveratio = rack->r_ctl.sack_moved_extra;
8028 		moveratio *= (uint64_t)1000;
8029 		if (movetotal)
8030 			moveratio /= movetotal;
8031 		else {
8032 			/* No moves, thats pretty good */
8033 			moveratio = 0;
8034 		}
8035 		if ((rack->sack_attack_disable == 0) &&
8036 		    (moveratio > rack_highest_move_thresh_seen))
8037 			rack_highest_move_thresh_seen = (uint32_t)moveratio;
8038 		if (rack->sack_attack_disable == 0) {
8039 			if ((ackratio > tcp_sack_to_ack_thresh) &&
8040 			    (moveratio > tcp_sack_to_move_thresh)) {
8041 				/* Disable sack processing */
8042 				rack->sack_attack_disable = 1;
8043 				if (rack->r_rep_attack == 0) {
8044 					rack->r_rep_attack = 1;
8045 					counter_u64_add(rack_sack_attacks_detected, 1);
8046 				}
8047 				if (tcp_attack_on_turns_on_logging) {
8048 					/*
8049 					 * Turn on logging, used for debugging
8050 					 * false positives.
8051 					 */
8052 					rack->rc_tp->t_logstate = tcp_attack_on_turns_on_logging;
8053 				}
8054 				/* Clamp the cwnd at flight size */
8055 				rack->r_ctl.rc_saved_cwnd = rack->rc_tp->snd_cwnd;
8056 				rack->rc_tp->snd_cwnd = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
8057 				rack_log_sad(rack, 2);
8058 			}
8059 		} else {
8060 			/* We are sack-disabled check for false positives */
8061 			if ((ackratio <= tcp_restoral_thresh) ||
8062 			    (rack->r_ctl.rc_num_maps_alloced  < tcp_map_minimum)) {
8063 				rack->sack_attack_disable  = 0;
8064 				rack_log_sad(rack, 3);
8065 				/* Restart counting */
8066 				rack->r_ctl.sack_count = 0;
8067 				rack->r_ctl.sack_moved_extra = 0;
8068 				rack->r_ctl.sack_noextra_move = 1;
8069 				rack->r_ctl.ack_count = max(1,
8070 				      (BYTES_THIS_ACK(tp, th)/ctf_fixed_maxseg(rack->rc_tp)));
8071 
8072 				if (rack->r_rep_reverse == 0) {
8073 					rack->r_rep_reverse = 1;
8074 					counter_u64_add(rack_sack_attacks_reversed, 1);
8075 				}
8076 				/* Restore the cwnd */
8077 				if (rack->r_ctl.rc_saved_cwnd > rack->rc_tp->snd_cwnd)
8078 					rack->rc_tp->snd_cwnd = rack->r_ctl.rc_saved_cwnd;
8079 			}
8080 		}
8081 	}
8082 #endif
8083 	if (changed) {
8084 		/* Something changed cancel the rack timer */
8085 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
8086 	}
8087 	tsused = tcp_ts_getticks();
8088 	rsm = tcp_rack_output(tp, rack, tsused);
8089 	if ((!IN_RECOVERY(tp->t_flags)) &&
8090 	    rsm) {
8091 		/* Enter recovery */
8092 		rack->r_ctl.rc_rsm_start = rsm->r_start;
8093 		rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
8094 		rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
8095 		entered_recovery = 1;
8096 		rack_cong_signal(tp, NULL, CC_NDUPACK);
8097 		/*
8098 		 * When we enter recovery we need to assure we send
8099 		 * one packet.
8100 		 */
8101 		if (rack->rack_no_prr == 0) {
8102 			rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
8103 			rack_log_to_prr(rack, 8, 0);
8104 		}
8105 		rack->r_timer_override = 1;
8106 		rack->r_early = 0;
8107 		rack->r_ctl.rc_agg_early = 0;
8108 	} else if (IN_RECOVERY(tp->t_flags) &&
8109 		   rsm &&
8110  		   (rack->r_rr_config == 3)) {
8111 		/*
8112 		 * Assure we can output and we get no
8113 		 * remembered pace time except the retransmit.
8114 		 */
8115 		rack->r_timer_override = 1;
8116 		rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
8117 		rack->r_ctl.rc_resend = rsm;
8118 	}
8119 	if (IN_RECOVERY(tp->t_flags) &&
8120 	    (rack->rack_no_prr == 0) &&
8121 	    (entered_recovery == 0)) {
8122 		/* Deal with PRR here (in recovery only) */
8123 		uint32_t pipe, snd_una;
8124 
8125 		rack->r_ctl.rc_prr_delivered += changed;
8126 		/* Compute prr_sndcnt */
8127 		if (SEQ_GT(tp->snd_una, th_ack)) {
8128 			snd_una = tp->snd_una;
8129 		} else {
8130 			snd_una = th_ack;
8131 		}
8132 		pipe = ((tp->snd_max - snd_una) - rack->r_ctl.rc_sacked) + rack->r_ctl.rc_holes_rxt;
8133 		if (pipe > tp->snd_ssthresh) {
8134 			long sndcnt;
8135 
8136 			sndcnt = rack->r_ctl.rc_prr_delivered * tp->snd_ssthresh;
8137 			if (rack->r_ctl.rc_prr_recovery_fs > 0)
8138 				sndcnt /= (long)rack->r_ctl.rc_prr_recovery_fs;
8139 			else {
8140 				rack->r_ctl.rc_prr_sndcnt = 0;
8141 				rack_log_to_prr(rack, 9, 0);
8142 				sndcnt = 0;
8143 			}
8144 			sndcnt++;
8145 			if (sndcnt > (long)rack->r_ctl.rc_prr_out)
8146 				sndcnt -= rack->r_ctl.rc_prr_out;
8147 			else
8148 				sndcnt = 0;
8149 			rack->r_ctl.rc_prr_sndcnt = sndcnt;
8150 			rack_log_to_prr(rack, 10, 0);
8151 		} else {
8152 			uint32_t limit;
8153 
8154 			if (rack->r_ctl.rc_prr_delivered > rack->r_ctl.rc_prr_out)
8155 				limit = (rack->r_ctl.rc_prr_delivered - rack->r_ctl.rc_prr_out);
8156 			else
8157 				limit = 0;
8158 			if (changed > limit)
8159 				limit = changed;
8160 			limit += ctf_fixed_maxseg(tp);
8161 			if (tp->snd_ssthresh > pipe) {
8162 				rack->r_ctl.rc_prr_sndcnt = min((tp->snd_ssthresh - pipe), limit);
8163 				rack_log_to_prr(rack, 11, 0);
8164 			} else {
8165 				rack->r_ctl.rc_prr_sndcnt = min(0, limit);
8166 				rack_log_to_prr(rack, 12, 0);
8167 			}
8168 		}
8169 		if ((rsm && (rack->r_ctl.rc_prr_sndcnt >= ctf_fixed_maxseg(tp)) &&
8170 		     ((rack->rc_inp->inp_in_hpts == 0) &&
8171 		      ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0)))) {
8172 			/*
8173 			 * If you are pacing output you don't want
8174 			 * to override.
8175 			 */
8176 			rack->r_early = 0;
8177 			rack->r_ctl.rc_agg_early = 0;
8178 			rack->r_timer_override = 1;
8179 		}
8180 	}
8181 }
8182 
8183 static void
8184 rack_strike_dupack(struct tcp_rack *rack)
8185 {
8186 	struct rack_sendmap *rsm;
8187 
8188 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
8189 	if (rsm && (rsm->r_dupack < 0xff)) {
8190 		rsm->r_dupack++;
8191 		if (rsm->r_dupack >= DUP_ACK_THRESHOLD) {
8192 			rack->r_wanted_output = 1;
8193 			rack->r_timer_override = 1;
8194 			rack_log_retran_reason(rack, rsm, __LINE__, 1, 3);
8195 		} else {
8196 			rack_log_retran_reason(rack, rsm, __LINE__, 0, 3);
8197 		}
8198 	}
8199 }
8200 
8201 static void
8202 rack_check_bottom_drag(struct tcpcb *tp,
8203 		       struct tcp_rack *rack,
8204 		       struct socket *so, int32_t acked)
8205 {
8206 	uint32_t segsiz, minseg;
8207 
8208 	segsiz = ctf_fixed_maxseg(tp);
8209 	if (so->so_snd.sb_flags & SB_TLS_IFNET) {
8210 		minseg = rack->r_ctl.rc_pace_min_segs;
8211 	} else {
8212 		minseg = segsiz;
8213 	}
8214 	if (tp->snd_max == tp->snd_una) {
8215 		/*
8216 		 * We are doing dynamic pacing and we are way
8217 		 * under. Basically everything got acked while
8218 		 * we were still waiting on the pacer to expire.
8219 		 *
8220 		 * This means we need to boost the b/w in
8221 		 * addition to any earlier boosting of
8222 		 * the multipler.
8223 		 */
8224 		rack->rc_dragged_bottom = 1;
8225 		rack_validate_multipliers_at_or_above100(rack);
8226 		/*
8227 		 * Lets use the segment bytes acked plus
8228 		 * the lowest RTT seen as the basis to
8229 		 * form a b/w estimate. This will be off
8230 		 * due to the fact that the true estimate
8231 		 * should be around 1/2 the time of the RTT
8232 		 * but we can settle for that.
8233 		 */
8234 		if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_VALID) &&
8235 		    acked) {
8236 			uint64_t bw, calc_bw, rtt;
8237 
8238 			rtt = rack->r_ctl.rack_rs.rs_us_rtt;
8239 			bw = acked;
8240 			calc_bw = bw * 1000000;
8241 			calc_bw /= rtt;
8242 			if (rack->r_ctl.last_max_bw &&
8243 			    (rack->r_ctl.last_max_bw < calc_bw)) {
8244 				/*
8245 				 * If we have a last calculated max bw
8246 				 * enforce it.
8247 				 */
8248 				calc_bw = rack->r_ctl.last_max_bw;
8249 			}
8250 			/* now plop it in */
8251 			if (rack->rc_gp_filled == 0) {
8252 				if (calc_bw > ONE_POINT_TWO_MEG) {
8253 					/*
8254 					 * If we have no measurement
8255 					 * don't let us set in more than
8256 					 * 1.2Mbps. If we are still too
8257 					 * low after pacing with this we
8258 					 * will hopefully have a max b/w
8259 					 * available to sanity check things.
8260 					 */
8261 					calc_bw = ONE_POINT_TWO_MEG;
8262 				}
8263 				rack->r_ctl.rc_rtt_diff = 0;
8264 				rack->r_ctl.gp_bw = calc_bw;
8265 				rack->rc_gp_filled = 1;
8266 				rack->r_ctl.num_avg = RACK_REQ_AVG;
8267 				rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
8268 			} else if (calc_bw > rack->r_ctl.gp_bw) {
8269 				rack->r_ctl.rc_rtt_diff = 0;
8270 				rack->r_ctl.num_avg = RACK_REQ_AVG;
8271 				rack->r_ctl.gp_bw = calc_bw;
8272 				rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
8273 			} else
8274 				rack_increase_bw_mul(rack, -1, 0, 0, 1);
8275 			/*
8276 			 * For acks over 1mss we do a extra boost to simulate
8277 			 * where we would get 2 acks (we want 110 for the mul).
8278 			 */
8279 			if (acked > segsiz)
8280 				rack_increase_bw_mul(rack, -1, 0, 0, 1);
8281 		} else {
8282 			/*
8283 			 * Huh, this should not be, settle
8284 			 * for just an old increase.
8285 			 */
8286 			rack_increase_bw_mul(rack, -1, 0, 0, 1);
8287 		}
8288 	} else if ((IN_RECOVERY(tp->t_flags) == 0) &&
8289 		   (sbavail(&so->so_snd) > max((segsiz * (4 + rack_req_segs)),
8290 					       minseg)) &&
8291 		   (rack->r_ctl.cwnd_to_use > max((segsiz * (rack_req_segs + 2)), minseg)) &&
8292 		   (tp->snd_wnd > max((segsiz * (rack_req_segs + 2)), minseg)) &&
8293 		   (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) <=
8294 		    (segsiz * rack_req_segs))) {
8295 		/*
8296 		 * We are doing dynamic GP pacing and
8297 		 * we have everything except 1MSS or less
8298 		 * bytes left out. We are still pacing away.
8299 		 * And there is data that could be sent, This
8300 		 * means we are inserting delayed ack time in
8301 		 * our measurements because we are pacing too slow.
8302 		 */
8303 		rack_validate_multipliers_at_or_above100(rack);
8304 		rack->rc_dragged_bottom = 1;
8305 		rack_increase_bw_mul(rack, -1, 0, 0, 1);
8306 	}
8307 }
8308 
8309 /*
8310  * Return value of 1, we do not need to call rack_process_data().
8311  * return value of 0, rack_process_data can be called.
8312  * For ret_val if its 0 the TCP is locked, if its non-zero
8313  * its unlocked and probably unsafe to touch the TCB.
8314  */
8315 static int
8316 rack_process_ack(struct mbuf *m, struct tcphdr *th, struct socket *so,
8317     struct tcpcb *tp, struct tcpopt *to,
8318     uint32_t tiwin, int32_t tlen,
8319     int32_t * ofia, int32_t thflags, int32_t * ret_val)
8320 {
8321 	int32_t ourfinisacked = 0;
8322 	int32_t nsegs, acked_amount;
8323 	int32_t acked;
8324 	struct mbuf *mfree;
8325 	struct tcp_rack *rack;
8326 	int32_t under_pacing = 0;
8327 	int32_t recovery = 0;
8328 
8329 	rack = (struct tcp_rack *)tp->t_fb_ptr;
8330 	if (SEQ_GT(th->th_ack, tp->snd_max)) {
8331 		ctf_do_dropafterack(m, tp, th, thflags, tlen, ret_val);
8332 		rack->r_wanted_output = 1;
8333 		return (1);
8334 	}
8335 	if (rack->rc_gp_filled &&
8336 	    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
8337 		under_pacing = 1;
8338 	}
8339 	if (SEQ_GEQ(th->th_ack, tp->snd_una) || to->to_nsacks) {
8340 		if (rack->rc_in_persist)
8341 			tp->t_rxtshift = 0;
8342 		if ((th->th_ack == tp->snd_una) && (tiwin == tp->snd_wnd))
8343 			rack_strike_dupack(rack);
8344 		rack_log_ack(tp, to, th);
8345 	}
8346 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
8347 		/*
8348 		 * Old ack, behind (or duplicate to) the last one rcv'd
8349 		 * Note: Should mark reordering is occuring! We should also
8350 		 * look for sack blocks arriving e.g. ack 1, 4-4 then ack 1,
8351 		 * 3-3, 4-4 would be reording. As well as ack 1, 3-3 <no
8352 		 * retran and> ack 3
8353 		 */
8354 		return (0);
8355 	}
8356 	/*
8357 	 * If we reach this point, ACK is not a duplicate, i.e., it ACKs
8358 	 * something we sent.
8359 	 */
8360 	if (tp->t_flags & TF_NEEDSYN) {
8361 		/*
8362 		 * T/TCP: Connection was half-synchronized, and our SYN has
8363 		 * been ACK'd (so connection is now fully synchronized).  Go
8364 		 * to non-starred state, increment snd_una for ACK of SYN,
8365 		 * and check if we can do window scaling.
8366 		 */
8367 		tp->t_flags &= ~TF_NEEDSYN;
8368 		tp->snd_una++;
8369 		/* Do window scaling? */
8370 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
8371 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
8372 			tp->rcv_scale = tp->request_r_scale;
8373 			/* Send window already scaled. */
8374 		}
8375 	}
8376 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8377 	INP_WLOCK_ASSERT(tp->t_inpcb);
8378 
8379 	acked = BYTES_THIS_ACK(tp, th);
8380 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, nsegs);
8381 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
8382 	/*
8383 	 * If we just performed our first retransmit, and the ACK arrives
8384 	 * within our recovery window, then it was a mistake to do the
8385 	 * retransmit in the first place.  Recover our original cwnd and
8386 	 * ssthresh, and proceed to transmit where we left off.
8387 	 */
8388 	if (tp->t_flags & TF_PREVVALID) {
8389 		tp->t_flags &= ~TF_PREVVALID;
8390 		if (tp->t_rxtshift == 1 &&
8391 		    (int)(ticks - tp->t_badrxtwin) < 0)
8392 			rack_cong_signal(tp, th, CC_RTO_ERR);
8393 	}
8394 	if (acked) {
8395 		/* assure we are not backed off */
8396 		tp->t_rxtshift = 0;
8397 		rack->rc_tlp_in_progress = 0;
8398 		rack->r_ctl.rc_tlp_cnt_out = 0;
8399 		/*
8400 		 * If it is the RXT timer we want to
8401 		 * stop it, so we can restart a TLP.
8402 		 */
8403 		if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT)
8404 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
8405 #ifdef NETFLIX_HTTP_LOGGING
8406 		tcp_http_check_for_comp(rack->rc_tp, th->th_ack);
8407 #endif
8408 	}
8409 	/*
8410 	 * If we have a timestamp reply, update smoothed round trip time. If
8411 	 * no timestamp is present but transmit timer is running and timed
8412 	 * sequence number was acked, update smoothed round trip time. Since
8413 	 * we now have an rtt measurement, cancel the timer backoff (cf.,
8414 	 * Phil Karn's retransmit alg.). Recompute the initial retransmit
8415 	 * timer.
8416 	 *
8417 	 * Some boxes send broken timestamp replies during the SYN+ACK
8418 	 * phase, ignore timestamps of 0 or we could calculate a huge RTT
8419 	 * and blow up the retransmit timer.
8420 	 */
8421 	/*
8422 	 * If all outstanding data is acked, stop retransmit timer and
8423 	 * remember to restart (more output or persist). If there is more
8424 	 * data to be acked, restart retransmit timer, using current
8425 	 * (possibly backed-off) value.
8426 	 */
8427 	if (acked == 0) {
8428 		if (ofia)
8429 			*ofia = ourfinisacked;
8430 		return (0);
8431 	}
8432 	if (rack->r_ctl.rc_early_recovery) {
8433 		if (IN_RECOVERY(tp->t_flags)) {
8434 			if (SEQ_LT(th->th_ack, tp->snd_recover) &&
8435 			    (SEQ_LT(th->th_ack, tp->snd_max))) {
8436 				tcp_rack_partialack(tp, th);
8437 			} else {
8438 				rack_post_recovery(tp, th);
8439 				recovery = 1;
8440 			}
8441 		}
8442 	}
8443 	/*
8444 	 * Let the congestion control algorithm update congestion control
8445 	 * related information. This typically means increasing the
8446 	 * congestion window.
8447 	 */
8448 	rack_ack_received(tp, rack, th, nsegs, CC_ACK, recovery);
8449 	SOCKBUF_LOCK(&so->so_snd);
8450 	acked_amount = min(acked, (int)sbavail(&so->so_snd));
8451 	tp->snd_wnd -= acked_amount;
8452 	mfree = sbcut_locked(&so->so_snd, acked_amount);
8453 	if ((sbused(&so->so_snd) == 0) &&
8454 	    (acked > acked_amount) &&
8455 	    (tp->t_state >= TCPS_FIN_WAIT_1) &&
8456 	    (tp->t_flags & TF_SENTFIN)) {
8457 		/*
8458 		 * We must be sure our fin
8459 		 * was sent and acked (we can be
8460 		 * in FIN_WAIT_1 without having
8461 		 * sent the fin).
8462 		 */
8463 		ourfinisacked = 1;
8464 	}
8465 	/* NB: sowwakeup_locked() does an implicit unlock. */
8466 	sowwakeup_locked(so);
8467 	m_freem(mfree);
8468 	if (rack->r_ctl.rc_early_recovery == 0) {
8469 		if (IN_RECOVERY(tp->t_flags)) {
8470 			if (SEQ_LT(th->th_ack, tp->snd_recover) &&
8471 			    (SEQ_LT(th->th_ack, tp->snd_max))) {
8472 				tcp_rack_partialack(tp, th);
8473 			} else {
8474 				rack_post_recovery(tp, th);
8475 			}
8476 		}
8477 	}
8478 	tp->snd_una = th->th_ack;
8479 	if (SEQ_GT(tp->snd_una, tp->snd_recover))
8480 		tp->snd_recover = tp->snd_una;
8481 
8482 	if (SEQ_LT(tp->snd_nxt, tp->snd_una)) {
8483 		tp->snd_nxt = tp->snd_una;
8484 	}
8485 	if (under_pacing &&
8486 	    (rack->use_fixed_rate == 0) &&
8487 	    (rack->in_probe_rtt == 0) &&
8488 	    rack->rc_gp_dyn_mul &&
8489 	    rack->rc_always_pace) {
8490 		/* Check if we are dragging bottom */
8491 		rack_check_bottom_drag(tp, rack, so, acked);
8492 	}
8493 	if (tp->snd_una == tp->snd_max) {
8494 		/* Nothing left outstanding */
8495 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
8496 		if (rack->r_ctl.rc_went_idle_time == 0)
8497 			rack->r_ctl.rc_went_idle_time = 1;
8498 		rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__);
8499 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
8500 			tp->t_acktime = 0;
8501 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
8502 		/* Set need output so persist might get set */
8503 		rack->r_wanted_output = 1;
8504 		sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
8505 		if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
8506 		    (sbavail(&so->so_snd) == 0) &&
8507 		    (tp->t_flags2 & TF2_DROP_AF_DATA)) {
8508 			/*
8509 			 * The socket was gone and the
8510 			 * peer sent data, time to
8511 			 * reset him.
8512 			 */
8513 			*ret_val = 1;
8514 			/* tcp_close will kill the inp pre-log the Reset */
8515 			tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
8516 			tp = tcp_close(tp);
8517 			ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, tlen);
8518 			return (1);
8519 
8520 		}
8521 	}
8522 	if (ofia)
8523 		*ofia = ourfinisacked;
8524 	return (0);
8525 }
8526 
8527 static void
8528 rack_collapsed_window(struct tcp_rack *rack)
8529 {
8530 	/*
8531 	 * Now we must walk the
8532 	 * send map and divide the
8533 	 * ones left stranded. These
8534 	 * guys can't cause us to abort
8535 	 * the connection and are really
8536 	 * "unsent". However if a buggy
8537 	 * client actually did keep some
8538 	 * of the data i.e. collapsed the win
8539 	 * and refused to ack and then opened
8540 	 * the win and acked that data. We would
8541 	 * get into an ack war, the simplier
8542 	 * method then of just pretending we
8543 	 * did not send those segments something
8544 	 * won't work.
8545 	 */
8546 	struct rack_sendmap *rsm, *nrsm, fe, *insret;
8547 	tcp_seq max_seq;
8548 
8549 	max_seq = rack->rc_tp->snd_una + rack->rc_tp->snd_wnd;
8550 	memset(&fe, 0, sizeof(fe));
8551 	fe.r_start = max_seq;
8552 	/* Find the first seq past or at maxseq */
8553 	rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
8554 	if (rsm == NULL) {
8555 		/* Nothing to do strange */
8556 		rack->rc_has_collapsed = 0;
8557 		return;
8558 	}
8559 	/*
8560 	 * Now do we need to split at
8561 	 * the collapse point?
8562 	 */
8563 	if (SEQ_GT(max_seq, rsm->r_start)) {
8564 		nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
8565 		if (nrsm == NULL) {
8566 			/* We can't get a rsm, mark all? */
8567 			nrsm = rsm;
8568 			goto no_split;
8569 		}
8570 		/* Clone it */
8571 		rack_clone_rsm(rack, nrsm, rsm, max_seq);
8572 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
8573 #ifdef INVARIANTS
8574 		if (insret != NULL) {
8575 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
8576 			      nrsm, insret, rack, rsm);
8577 		}
8578 #endif
8579 		if (rsm->r_in_tmap) {
8580 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
8581 			nrsm->r_in_tmap = 1;
8582 		}
8583 		/*
8584 		 * Set in the new RSM as the
8585 		 * collapsed starting point
8586 		 */
8587 		rsm = nrsm;
8588 	}
8589 no_split:
8590 	counter_u64_add(rack_collapsed_win, 1);
8591 	RB_FOREACH_FROM(nrsm, rack_rb_tree_head, rsm) {
8592 		nrsm->r_flags |= RACK_RWND_COLLAPSED;
8593 		rack->rc_has_collapsed = 1;
8594 	}
8595 }
8596 
8597 static void
8598 rack_un_collapse_window(struct tcp_rack *rack)
8599 {
8600 	struct rack_sendmap *rsm;
8601 
8602 	RB_FOREACH_REVERSE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
8603 		if (rsm->r_flags & RACK_RWND_COLLAPSED)
8604 			rsm->r_flags &= ~RACK_RWND_COLLAPSED;
8605 		else
8606 			break;
8607 	}
8608 	rack->rc_has_collapsed = 0;
8609 }
8610 
8611 static void
8612 rack_handle_delayed_ack(struct tcpcb *tp, struct tcp_rack *rack,
8613 			int32_t tlen, int32_t tfo_syn)
8614 {
8615 	if (DELAY_ACK(tp, tlen) || tfo_syn) {
8616 		if (rack->rc_dack_mode &&
8617 		    (tlen > 500) &&
8618 		    (rack->rc_dack_toggle == 1)) {
8619 			goto no_delayed_ack;
8620 		}
8621 		rack_timer_cancel(tp, rack,
8622 				  rack->r_ctl.rc_rcvtime, __LINE__);
8623 		tp->t_flags |= TF_DELACK;
8624 	} else {
8625 no_delayed_ack:
8626 		rack->r_wanted_output = 1;
8627 		tp->t_flags |= TF_ACKNOW;
8628 		if (rack->rc_dack_mode) {
8629 			if (tp->t_flags & TF_DELACK)
8630 				rack->rc_dack_toggle = 1;
8631 			else
8632 				rack->rc_dack_toggle = 0;
8633 		}
8634 	}
8635 }
8636 /*
8637  * Return value of 1, the TCB is unlocked and most
8638  * likely gone, return value of 0, the TCP is still
8639  * locked.
8640  */
8641 static int
8642 rack_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so,
8643     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
8644     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
8645 {
8646 	/*
8647 	 * Update window information. Don't look at window if no ACK: TAC's
8648 	 * send garbage on first SYN.
8649 	 */
8650 	int32_t nsegs;
8651 	int32_t tfo_syn;
8652 	struct tcp_rack *rack;
8653 
8654 	rack = (struct tcp_rack *)tp->t_fb_ptr;
8655 	INP_WLOCK_ASSERT(tp->t_inpcb);
8656 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8657 	if ((thflags & TH_ACK) &&
8658 	    (SEQ_LT(tp->snd_wl1, th->th_seq) ||
8659 	    (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
8660 	    (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
8661 		/* keep track of pure window updates */
8662 		if (tlen == 0 &&
8663 		    tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd)
8664 			KMOD_TCPSTAT_INC(tcps_rcvwinupd);
8665 		tp->snd_wnd = tiwin;
8666 		tp->snd_wl1 = th->th_seq;
8667 		tp->snd_wl2 = th->th_ack;
8668 		if (tp->snd_wnd > tp->max_sndwnd)
8669 			tp->max_sndwnd = tp->snd_wnd;
8670 		rack->r_wanted_output = 1;
8671 	} else if (thflags & TH_ACK) {
8672 		if ((tp->snd_wl2 == th->th_ack) && (tiwin < tp->snd_wnd)) {
8673 			tp->snd_wnd = tiwin;
8674 			tp->snd_wl1 = th->th_seq;
8675 			tp->snd_wl2 = th->th_ack;
8676 		}
8677 	}
8678 	if (tp->snd_wnd < ctf_outstanding(tp))
8679 		/* The peer collapsed the window */
8680 		rack_collapsed_window(rack);
8681 	else if (rack->rc_has_collapsed)
8682 		rack_un_collapse_window(rack);
8683 	/* Was persist timer active and now we have window space? */
8684 	if ((rack->rc_in_persist != 0) &&
8685 	    (tp->snd_wnd >= min((rack->r_ctl.rc_high_rwnd/2),
8686 				rack->r_ctl.rc_pace_min_segs))) {
8687 		rack_exit_persist(tp, rack, rack->r_ctl.rc_rcvtime);
8688 		tp->snd_nxt = tp->snd_max;
8689 		/* Make sure we output to start the timer */
8690 		rack->r_wanted_output = 1;
8691 	}
8692 	/* Do we enter persists? */
8693 	if ((rack->rc_in_persist == 0) &&
8694 	    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), rack->r_ctl.rc_pace_min_segs)) &&
8695 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
8696 	    (tp->snd_max == tp->snd_una) &&
8697 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
8698 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
8699 		/*
8700 		 * Here the rwnd is less than
8701 		 * the pacing size, we are established,
8702 		 * nothing is outstanding, and there is
8703 		 * data to send. Enter persists.
8704 		 */
8705 		tp->snd_nxt = tp->snd_una;
8706 		rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
8707 	}
8708 	if (tp->t_flags2 & TF2_DROP_AF_DATA) {
8709 		m_freem(m);
8710 		return (0);
8711 	}
8712 	/*
8713 	 * don't process the URG bit, ignore them drag
8714 	 * along the up.
8715 	 */
8716 	tp->rcv_up = tp->rcv_nxt;
8717 	INP_WLOCK_ASSERT(tp->t_inpcb);
8718 
8719 	/*
8720 	 * Process the segment text, merging it into the TCP sequencing
8721 	 * queue, and arranging for acknowledgment of receipt if necessary.
8722 	 * This process logically involves adjusting tp->rcv_wnd as data is
8723 	 * presented to the user (this happens in tcp_usrreq.c, case
8724 	 * PRU_RCVD).  If a FIN has already been received on this connection
8725 	 * then we just ignore the text.
8726 	 */
8727 	tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) &&
8728 		   IS_FASTOPEN(tp->t_flags));
8729 	if ((tlen || (thflags & TH_FIN) || (tfo_syn && tlen > 0)) &&
8730 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
8731 		tcp_seq save_start = th->th_seq;
8732 		tcp_seq save_rnxt  = tp->rcv_nxt;
8733 		int     save_tlen  = tlen;
8734 
8735 		m_adj(m, drop_hdrlen);	/* delayed header drop */
8736 		/*
8737 		 * Insert segment which includes th into TCP reassembly
8738 		 * queue with control block tp.  Set thflags to whether
8739 		 * reassembly now includes a segment with FIN.  This handles
8740 		 * the common case inline (segment is the next to be
8741 		 * received on an established connection, and the queue is
8742 		 * empty), avoiding linkage into and removal from the queue
8743 		 * and repetition of various conversions. Set DELACK for
8744 		 * segments received in order, but ack immediately when
8745 		 * segments are out of order (so fast retransmit can work).
8746 		 */
8747 		if (th->th_seq == tp->rcv_nxt &&
8748 		    SEGQ_EMPTY(tp) &&
8749 		    (TCPS_HAVEESTABLISHED(tp->t_state) ||
8750 		    tfo_syn)) {
8751 #ifdef NETFLIX_SB_LIMITS
8752 			u_int mcnt, appended;
8753 
8754 			if (so->so_rcv.sb_shlim) {
8755 				mcnt = m_memcnt(m);
8756 				appended = 0;
8757 				if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
8758 				    CFO_NOSLEEP, NULL) == false) {
8759 					counter_u64_add(tcp_sb_shlim_fails, 1);
8760 					m_freem(m);
8761 					return (0);
8762 				}
8763 			}
8764 #endif
8765 			rack_handle_delayed_ack(tp, rack, tlen, tfo_syn);
8766 			tp->rcv_nxt += tlen;
8767 			if (tlen &&
8768 			    ((tp->t_flags2 & TF2_FBYTES_COMPLETE) == 0) &&
8769 			    (tp->t_fbyte_in == 0)) {
8770 				tp->t_fbyte_in = ticks;
8771 				if (tp->t_fbyte_in == 0)
8772 					tp->t_fbyte_in = 1;
8773 				if (tp->t_fbyte_out && tp->t_fbyte_in)
8774 					tp->t_flags2 |= TF2_FBYTES_COMPLETE;
8775 			}
8776 			thflags = th->th_flags & TH_FIN;
8777 			KMOD_TCPSTAT_ADD(tcps_rcvpack, nsegs);
8778 			KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
8779 			SOCKBUF_LOCK(&so->so_rcv);
8780 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
8781 				m_freem(m);
8782 			} else
8783 #ifdef NETFLIX_SB_LIMITS
8784 				appended =
8785 #endif
8786 					sbappendstream_locked(&so->so_rcv, m, 0);
8787 			/* NB: sorwakeup_locked() does an implicit unlock. */
8788 			sorwakeup_locked(so);
8789 #ifdef NETFLIX_SB_LIMITS
8790 			if (so->so_rcv.sb_shlim && appended != mcnt)
8791 				counter_fo_release(so->so_rcv.sb_shlim,
8792 				    mcnt - appended);
8793 #endif
8794 		} else {
8795 			/*
8796 			 * XXX: Due to the header drop above "th" is
8797 			 * theoretically invalid by now.  Fortunately
8798 			 * m_adj() doesn't actually frees any mbufs when
8799 			 * trimming from the head.
8800 			 */
8801 			tcp_seq temp = save_start;
8802 			thflags = tcp_reass(tp, th, &temp, &tlen, m);
8803 			tp->t_flags |= TF_ACKNOW;
8804 		}
8805                 if ((tp->t_flags & TF_SACK_PERMIT) && (save_tlen > 0)) {
8806                         if ((tlen == 0) && (SEQ_LT(save_start, save_rnxt))) {
8807                                 /*
8808                                  * DSACK actually handled in the fastpath
8809                                  * above.
8810                                  */
8811 				RACK_OPTS_INC(tcp_sack_path_1);
8812                                 tcp_update_sack_list(tp, save_start,
8813                                     save_start + save_tlen);
8814                         } else if ((tlen > 0) && SEQ_GT(tp->rcv_nxt, save_rnxt)) {
8815                                 if ((tp->rcv_numsacks >= 1) &&
8816                                     (tp->sackblks[0].end == save_start)) {
8817                                         /*
8818                                          * Partial overlap, recorded at todrop
8819                                          * above.
8820                                          */
8821 					RACK_OPTS_INC(tcp_sack_path_2a);
8822                                         tcp_update_sack_list(tp,
8823                                             tp->sackblks[0].start,
8824                                             tp->sackblks[0].end);
8825                                 } else {
8826 					RACK_OPTS_INC(tcp_sack_path_2b);
8827                                         tcp_update_dsack_list(tp, save_start,
8828                                             save_start + save_tlen);
8829                                 }
8830                         } else if (tlen >= save_tlen) {
8831                                 /* Update of sackblks. */
8832 				RACK_OPTS_INC(tcp_sack_path_3);
8833                                 tcp_update_dsack_list(tp, save_start,
8834                                     save_start + save_tlen);
8835                         } else if (tlen > 0) {
8836 				RACK_OPTS_INC(tcp_sack_path_4);
8837                                 tcp_update_dsack_list(tp, save_start,
8838                                     save_start + tlen);
8839                         }
8840                 }
8841 	} else {
8842 		m_freem(m);
8843 		thflags &= ~TH_FIN;
8844 	}
8845 
8846 	/*
8847 	 * If FIN is received ACK the FIN and let the user know that the
8848 	 * connection is closing.
8849 	 */
8850 	if (thflags & TH_FIN) {
8851 		if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
8852 			socantrcvmore(so);
8853 			/*
8854 			 * If connection is half-synchronized (ie NEEDSYN
8855 			 * flag on) then delay ACK, so it may be piggybacked
8856 			 * when SYN is sent. Otherwise, since we received a
8857 			 * FIN then no more input can be expected, send ACK
8858 			 * now.
8859 			 */
8860 			if (tp->t_flags & TF_NEEDSYN) {
8861 				rack_timer_cancel(tp, rack,
8862 				    rack->r_ctl.rc_rcvtime, __LINE__);
8863 				tp->t_flags |= TF_DELACK;
8864 			} else {
8865 				tp->t_flags |= TF_ACKNOW;
8866 			}
8867 			tp->rcv_nxt++;
8868 		}
8869 		switch (tp->t_state) {
8870 
8871 			/*
8872 			 * In SYN_RECEIVED and ESTABLISHED STATES enter the
8873 			 * CLOSE_WAIT state.
8874 			 */
8875 		case TCPS_SYN_RECEIVED:
8876 			tp->t_starttime = ticks;
8877 			/* FALLTHROUGH */
8878 		case TCPS_ESTABLISHED:
8879 			rack_timer_cancel(tp, rack,
8880 			    rack->r_ctl.rc_rcvtime, __LINE__);
8881 			tcp_state_change(tp, TCPS_CLOSE_WAIT);
8882 			break;
8883 
8884 			/*
8885 			 * If still in FIN_WAIT_1 STATE FIN has not been
8886 			 * acked so enter the CLOSING state.
8887 			 */
8888 		case TCPS_FIN_WAIT_1:
8889 			rack_timer_cancel(tp, rack,
8890 			    rack->r_ctl.rc_rcvtime, __LINE__);
8891 			tcp_state_change(tp, TCPS_CLOSING);
8892 			break;
8893 
8894 			/*
8895 			 * In FIN_WAIT_2 state enter the TIME_WAIT state,
8896 			 * starting the time-wait timer, turning off the
8897 			 * other standard timers.
8898 			 */
8899 		case TCPS_FIN_WAIT_2:
8900 			rack_timer_cancel(tp, rack,
8901 			    rack->r_ctl.rc_rcvtime, __LINE__);
8902 			tcp_twstart(tp);
8903 			return (1);
8904 		}
8905 	}
8906 	/*
8907 	 * Return any desired output.
8908 	 */
8909 	if ((tp->t_flags & TF_ACKNOW) ||
8910 	    (sbavail(&so->so_snd) > (tp->snd_max - tp->snd_una))) {
8911 		rack->r_wanted_output = 1;
8912 	}
8913 	INP_WLOCK_ASSERT(tp->t_inpcb);
8914 	return (0);
8915 }
8916 
8917 /*
8918  * Here nothing is really faster, its just that we
8919  * have broken out the fast-data path also just like
8920  * the fast-ack.
8921  */
8922 static int
8923 rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so,
8924     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
8925     uint32_t tiwin, int32_t nxt_pkt, uint8_t iptos)
8926 {
8927 	int32_t nsegs;
8928 	int32_t newsize = 0;	/* automatic sockbuf scaling */
8929 	struct tcp_rack *rack;
8930 #ifdef NETFLIX_SB_LIMITS
8931 	u_int mcnt, appended;
8932 #endif
8933 #ifdef TCPDEBUG
8934 	/*
8935 	 * The size of tcp_saveipgen must be the size of the max ip header,
8936 	 * now IPv6.
8937 	 */
8938 	u_char tcp_saveipgen[IP6_HDR_LEN];
8939 	struct tcphdr tcp_savetcp;
8940 	short ostate = 0;
8941 
8942 #endif
8943 	/*
8944 	 * If last ACK falls within this segment's sequence numbers, record
8945 	 * the timestamp. NOTE that the test is modified according to the
8946 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
8947 	 */
8948 	if (__predict_false(th->th_seq != tp->rcv_nxt)) {
8949 		return (0);
8950 	}
8951 	if (__predict_false(tp->snd_nxt != tp->snd_max)) {
8952 		return (0);
8953 	}
8954 	if (tiwin && tiwin != tp->snd_wnd) {
8955 		return (0);
8956 	}
8957 	if (__predict_false((tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN)))) {
8958 		return (0);
8959 	}
8960 	if (__predict_false((to->to_flags & TOF_TS) &&
8961 	    (TSTMP_LT(to->to_tsval, tp->ts_recent)))) {
8962 		return (0);
8963 	}
8964 	if (__predict_false((th->th_ack != tp->snd_una))) {
8965 		return (0);
8966 	}
8967 	if (__predict_false(tlen > sbspace(&so->so_rcv))) {
8968 		return (0);
8969 	}
8970 	if ((to->to_flags & TOF_TS) != 0 &&
8971 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
8972 		tp->ts_recent_age = tcp_ts_getticks();
8973 		tp->ts_recent = to->to_tsval;
8974 	}
8975 	rack = (struct tcp_rack *)tp->t_fb_ptr;
8976 	/*
8977 	 * This is a pure, in-sequence data packet with nothing on the
8978 	 * reassembly queue and we have enough buffer space to take it.
8979 	 */
8980 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8981 
8982 #ifdef NETFLIX_SB_LIMITS
8983 	if (so->so_rcv.sb_shlim) {
8984 		mcnt = m_memcnt(m);
8985 		appended = 0;
8986 		if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
8987 		    CFO_NOSLEEP, NULL) == false) {
8988 			counter_u64_add(tcp_sb_shlim_fails, 1);
8989 			m_freem(m);
8990 			return (1);
8991 		}
8992 	}
8993 #endif
8994 	/* Clean receiver SACK report if present */
8995 	if (tp->rcv_numsacks)
8996 		tcp_clean_sackreport(tp);
8997 	KMOD_TCPSTAT_INC(tcps_preddat);
8998 	tp->rcv_nxt += tlen;
8999 	if (tlen &&
9000 	    ((tp->t_flags2 & TF2_FBYTES_COMPLETE) == 0) &&
9001 	    (tp->t_fbyte_in == 0)) {
9002 		tp->t_fbyte_in = ticks;
9003 		if (tp->t_fbyte_in == 0)
9004 			tp->t_fbyte_in = 1;
9005 		if (tp->t_fbyte_out && tp->t_fbyte_in)
9006 			tp->t_flags2 |= TF2_FBYTES_COMPLETE;
9007 	}
9008 	/*
9009 	 * Pull snd_wl1 up to prevent seq wrap relative to th_seq.
9010 	 */
9011 	tp->snd_wl1 = th->th_seq;
9012 	/*
9013 	 * Pull rcv_up up to prevent seq wrap relative to rcv_nxt.
9014 	 */
9015 	tp->rcv_up = tp->rcv_nxt;
9016 	KMOD_TCPSTAT_ADD(tcps_rcvpack, nsegs);
9017 	KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
9018 #ifdef TCPDEBUG
9019 	if (so->so_options & SO_DEBUG)
9020 		tcp_trace(TA_INPUT, ostate, tp,
9021 		    (void *)tcp_saveipgen, &tcp_savetcp, 0);
9022 #endif
9023 	newsize = tcp_autorcvbuf(m, th, so, tp, tlen);
9024 
9025 	/* Add data to socket buffer. */
9026 	SOCKBUF_LOCK(&so->so_rcv);
9027 	if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9028 		m_freem(m);
9029 	} else {
9030 		/*
9031 		 * Set new socket buffer size. Give up when limit is
9032 		 * reached.
9033 		 */
9034 		if (newsize)
9035 			if (!sbreserve_locked(&so->so_rcv,
9036 			    newsize, so, NULL))
9037 				so->so_rcv.sb_flags &= ~SB_AUTOSIZE;
9038 		m_adj(m, drop_hdrlen);	/* delayed header drop */
9039 #ifdef NETFLIX_SB_LIMITS
9040 		appended =
9041 #endif
9042 			sbappendstream_locked(&so->so_rcv, m, 0);
9043 		ctf_calc_rwin(so, tp);
9044 	}
9045 	/* NB: sorwakeup_locked() does an implicit unlock. */
9046 	sorwakeup_locked(so);
9047 #ifdef NETFLIX_SB_LIMITS
9048 	if (so->so_rcv.sb_shlim && mcnt != appended)
9049 		counter_fo_release(so->so_rcv.sb_shlim, mcnt - appended);
9050 #endif
9051 	rack_handle_delayed_ack(tp, rack, tlen, 0);
9052 	if (tp->snd_una == tp->snd_max)
9053 		sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
9054 	return (1);
9055 }
9056 
9057 /*
9058  * This subfunction is used to try to highly optimize the
9059  * fast path. We again allow window updates that are
9060  * in sequence to remain in the fast-path. We also add
9061  * in the __predict's to attempt to help the compiler.
9062  * Note that if we return a 0, then we can *not* process
9063  * it and the caller should push the packet into the
9064  * slow-path.
9065  */
9066 static int
9067 rack_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
9068     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9069     uint32_t tiwin, int32_t nxt_pkt, uint32_t cts)
9070 {
9071 	int32_t acked;
9072 	int32_t nsegs;
9073 #ifdef TCPDEBUG
9074 	/*
9075 	 * The size of tcp_saveipgen must be the size of the max ip header,
9076 	 * now IPv6.
9077 	 */
9078 	u_char tcp_saveipgen[IP6_HDR_LEN];
9079 	struct tcphdr tcp_savetcp;
9080 	short ostate = 0;
9081 #endif
9082 	int32_t under_pacing = 0;
9083 	struct tcp_rack *rack;
9084 
9085 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
9086 		/* Old ack, behind (or duplicate to) the last one rcv'd */
9087 		return (0);
9088 	}
9089 	if (__predict_false(SEQ_GT(th->th_ack, tp->snd_max))) {
9090 		/* Above what we have sent? */
9091 		return (0);
9092 	}
9093 	if (__predict_false(tp->snd_nxt != tp->snd_max)) {
9094 		/* We are retransmitting */
9095 		return (0);
9096 	}
9097 	if (__predict_false(tiwin == 0)) {
9098 		/* zero window */
9099 		return (0);
9100 	}
9101 	if (__predict_false(tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN))) {
9102 		/* We need a SYN or a FIN, unlikely.. */
9103 		return (0);
9104 	}
9105 	if ((to->to_flags & TOF_TS) && __predict_false(TSTMP_LT(to->to_tsval, tp->ts_recent))) {
9106 		/* Timestamp is behind .. old ack with seq wrap? */
9107 		return (0);
9108 	}
9109 	if (__predict_false(IN_RECOVERY(tp->t_flags))) {
9110 		/* Still recovering */
9111 		return (0);
9112 	}
9113 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9114 	if (rack->r_ctl.rc_sacked) {
9115 		/* We have sack holes on our scoreboard */
9116 		return (0);
9117 	}
9118 	/* Ok if we reach here, we can process a fast-ack */
9119 	if (rack->rc_gp_filled &&
9120 	    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
9121 		under_pacing = 1;
9122 	}
9123 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
9124 	rack_log_ack(tp, to, th);
9125 	/* Did the window get updated? */
9126 	if (tiwin != tp->snd_wnd) {
9127 		tp->snd_wnd = tiwin;
9128 		tp->snd_wl1 = th->th_seq;
9129 		if (tp->snd_wnd > tp->max_sndwnd)
9130 			tp->max_sndwnd = tp->snd_wnd;
9131 	}
9132 	/* Do we exit persists? */
9133 	if ((rack->rc_in_persist != 0) &&
9134 	    (tp->snd_wnd >= min((rack->r_ctl.rc_high_rwnd/2),
9135 			       rack->r_ctl.rc_pace_min_segs))) {
9136 		rack_exit_persist(tp, rack, cts);
9137 	}
9138 	/* Do we enter persists? */
9139 	if ((rack->rc_in_persist == 0) &&
9140 	    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), rack->r_ctl.rc_pace_min_segs)) &&
9141 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
9142 	    (tp->snd_max == tp->snd_una) &&
9143 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
9144 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
9145 		/*
9146 		 * Here the rwnd is less than
9147 		 * the pacing size, we are established,
9148 		 * nothing is outstanding, and there is
9149 		 * data to send. Enter persists.
9150 		 */
9151 		tp->snd_nxt = tp->snd_una;
9152 		rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
9153 	}
9154 	/*
9155 	 * If last ACK falls within this segment's sequence numbers, record
9156 	 * the timestamp. NOTE that the test is modified according to the
9157 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
9158 	 */
9159 	if ((to->to_flags & TOF_TS) != 0 &&
9160 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
9161 		tp->ts_recent_age = tcp_ts_getticks();
9162 		tp->ts_recent = to->to_tsval;
9163 	}
9164 	/*
9165 	 * This is a pure ack for outstanding data.
9166 	 */
9167 	KMOD_TCPSTAT_INC(tcps_predack);
9168 
9169 	/*
9170 	 * "bad retransmit" recovery.
9171 	 */
9172 	if (tp->t_flags & TF_PREVVALID) {
9173 		tp->t_flags &= ~TF_PREVVALID;
9174 		if (tp->t_rxtshift == 1 &&
9175 		    (int)(ticks - tp->t_badrxtwin) < 0)
9176 			rack_cong_signal(tp, th, CC_RTO_ERR);
9177 	}
9178 	/*
9179 	 * Recalculate the transmit timer / rtt.
9180 	 *
9181 	 * Some boxes send broken timestamp replies during the SYN+ACK
9182 	 * phase, ignore timestamps of 0 or we could calculate a huge RTT
9183 	 * and blow up the retransmit timer.
9184 	 */
9185 	acked = BYTES_THIS_ACK(tp, th);
9186 
9187 #ifdef TCP_HHOOK
9188 	/* Run HHOOK_TCP_ESTABLISHED_IN helper hooks. */
9189 	hhook_run_tcp_est_in(tp, th, to);
9190 #endif
9191 
9192 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, nsegs);
9193 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
9194 	sbdrop(&so->so_snd, acked);
9195 	if (acked) {
9196 		/* assure we are not backed off */
9197 		tp->t_rxtshift = 0;
9198 		rack->rc_tlp_in_progress = 0;
9199 		rack->r_ctl.rc_tlp_cnt_out = 0;
9200 		/*
9201 		 * If it is the RXT timer we want to
9202 		 * stop it, so we can restart a TLP.
9203 		 */
9204 		if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT)
9205 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
9206 #ifdef NETFLIX_HTTP_LOGGING
9207 		tcp_http_check_for_comp(rack->rc_tp, th->th_ack);
9208 #endif
9209 	}
9210 	/*
9211 	 * Let the congestion control algorithm update congestion control
9212 	 * related information. This typically means increasing the
9213 	 * congestion window.
9214 	 */
9215 	rack_ack_received(tp, rack, th, nsegs, CC_ACK, 0);
9216 
9217 	tp->snd_una = th->th_ack;
9218 	if (tp->snd_wnd < ctf_outstanding(tp)) {
9219 		/* The peer collapsed the window */
9220 		rack_collapsed_window(rack);
9221 	} else if (rack->rc_has_collapsed)
9222 		rack_un_collapse_window(rack);
9223 
9224 	/*
9225 	 * Pull snd_wl2 up to prevent seq wrap relative to th_ack.
9226 	 */
9227 	tp->snd_wl2 = th->th_ack;
9228 	tp->t_dupacks = 0;
9229 	m_freem(m);
9230 	/* ND6_HINT(tp);	 *//* Some progress has been made. */
9231 
9232 	/*
9233 	 * If all outstanding data are acked, stop retransmit timer,
9234 	 * otherwise restart timer using current (possibly backed-off)
9235 	 * value. If process is waiting for space, wakeup/selwakeup/signal.
9236 	 * If data are ready to send, let tcp_output decide between more
9237 	 * output or persist.
9238 	 */
9239 #ifdef TCPDEBUG
9240 	if (so->so_options & SO_DEBUG)
9241 		tcp_trace(TA_INPUT, ostate, tp,
9242 		    (void *)tcp_saveipgen,
9243 		    &tcp_savetcp, 0);
9244 #endif
9245 	if (under_pacing &&
9246 	    (rack->use_fixed_rate == 0) &&
9247 	    (rack->in_probe_rtt == 0) &&
9248 	    rack->rc_gp_dyn_mul &&
9249 	    rack->rc_always_pace) {
9250 		/* Check if we are dragging bottom */
9251 		rack_check_bottom_drag(tp, rack, so, acked);
9252 	}
9253 	if (tp->snd_una == tp->snd_max) {
9254 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
9255 		if (rack->r_ctl.rc_went_idle_time == 0)
9256 			rack->r_ctl.rc_went_idle_time = 1;
9257 		rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__);
9258 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
9259 			tp->t_acktime = 0;
9260 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
9261 	}
9262 	/* Wake up the socket if we have room to write more */
9263 	sowwakeup(so);
9264 	if (sbavail(&so->so_snd)) {
9265 		rack->r_wanted_output = 1;
9266 	}
9267 	return (1);
9268 }
9269 
9270 /*
9271  * Return value of 1, the TCB is unlocked and most
9272  * likely gone, return value of 0, the TCP is still
9273  * locked.
9274  */
9275 static int
9276 rack_do_syn_sent(struct mbuf *m, struct tcphdr *th, struct socket *so,
9277     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9278     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9279 {
9280 	int32_t ret_val = 0;
9281 	int32_t todrop;
9282 	int32_t ourfinisacked = 0;
9283 	struct tcp_rack *rack;
9284 
9285 	ctf_calc_rwin(so, tp);
9286 	/*
9287 	 * If the state is SYN_SENT: if seg contains an ACK, but not for our
9288 	 * SYN, drop the input. if seg contains a RST, then drop the
9289 	 * connection. if seg does not contain SYN, then drop it. Otherwise
9290 	 * this is an acceptable SYN segment initialize tp->rcv_nxt and
9291 	 * tp->irs if seg contains ack then advance tp->snd_una if seg
9292 	 * contains an ECE and ECN support is enabled, the stream is ECN
9293 	 * capable. if SYN has been acked change to ESTABLISHED else
9294 	 * SYN_RCVD state arrange for segment to be acked (eventually)
9295 	 * continue processing rest of data/controls.
9296 	 */
9297 	if ((thflags & TH_ACK) &&
9298 	    (SEQ_LEQ(th->th_ack, tp->iss) ||
9299 	    SEQ_GT(th->th_ack, tp->snd_max))) {
9300 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9301 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9302 		return (1);
9303 	}
9304 	if ((thflags & (TH_ACK | TH_RST)) == (TH_ACK | TH_RST)) {
9305 		TCP_PROBE5(connect__refused, NULL, tp,
9306 		    mtod(m, const char *), tp, th);
9307 		tp = tcp_drop(tp, ECONNREFUSED);
9308 		ctf_do_drop(m, tp);
9309 		return (1);
9310 	}
9311 	if (thflags & TH_RST) {
9312 		ctf_do_drop(m, tp);
9313 		return (1);
9314 	}
9315 	if (!(thflags & TH_SYN)) {
9316 		ctf_do_drop(m, tp);
9317 		return (1);
9318 	}
9319 	tp->irs = th->th_seq;
9320 	tcp_rcvseqinit(tp);
9321 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9322 	if (thflags & TH_ACK) {
9323 		int tfo_partial = 0;
9324 
9325 		KMOD_TCPSTAT_INC(tcps_connects);
9326 		soisconnected(so);
9327 #ifdef MAC
9328 		mac_socketpeer_set_from_mbuf(m, so);
9329 #endif
9330 		/* Do window scaling on this connection? */
9331 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
9332 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
9333 			tp->rcv_scale = tp->request_r_scale;
9334 		}
9335 		tp->rcv_adv += min(tp->rcv_wnd,
9336 		    TCP_MAXWIN << tp->rcv_scale);
9337 		/*
9338 		 * If not all the data that was sent in the TFO SYN
9339 		 * has been acked, resend the remainder right away.
9340 		 */
9341 		if (IS_FASTOPEN(tp->t_flags) &&
9342 		    (tp->snd_una != tp->snd_max)) {
9343 			tp->snd_nxt = th->th_ack;
9344 			tfo_partial = 1;
9345 		}
9346 		/*
9347 		 * If there's data, delay ACK; if there's also a FIN ACKNOW
9348 		 * will be turned on later.
9349 		 */
9350 		if (DELAY_ACK(tp, tlen) && tlen != 0 && !tfo_partial) {
9351 			rack_timer_cancel(tp, rack,
9352 					  rack->r_ctl.rc_rcvtime, __LINE__);
9353 			tp->t_flags |= TF_DELACK;
9354 		} else {
9355 			rack->r_wanted_output = 1;
9356 			tp->t_flags |= TF_ACKNOW;
9357 			rack->rc_dack_toggle = 0;
9358 		}
9359 		if (((thflags & (TH_CWR | TH_ECE)) == TH_ECE) &&
9360 		    (V_tcp_do_ecn == 1)) {
9361 			tp->t_flags2 |= TF2_ECN_PERMIT;
9362 			KMOD_TCPSTAT_INC(tcps_ecn_shs);
9363 		}
9364 		if (SEQ_GT(th->th_ack, tp->snd_una)) {
9365 			/*
9366 			 * We advance snd_una for the
9367 			 * fast open case. If th_ack is
9368 			 * acknowledging data beyond
9369 			 * snd_una we can't just call
9370 			 * ack-processing since the
9371 			 * data stream in our send-map
9372 			 * will start at snd_una + 1 (one
9373 			 * beyond the SYN). If its just
9374 			 * equal we don't need to do that
9375 			 * and there is no send_map.
9376 			 */
9377 			tp->snd_una++;
9378 		}
9379 		/*
9380 		 * Received <SYN,ACK> in SYN_SENT[*] state. Transitions:
9381 		 * SYN_SENT  --> ESTABLISHED SYN_SENT* --> FIN_WAIT_1
9382 		 */
9383 		tp->t_starttime = ticks;
9384 		if (tp->t_flags & TF_NEEDFIN) {
9385 			tcp_state_change(tp, TCPS_FIN_WAIT_1);
9386 			tp->t_flags &= ~TF_NEEDFIN;
9387 			thflags &= ~TH_SYN;
9388 		} else {
9389 			tcp_state_change(tp, TCPS_ESTABLISHED);
9390 			TCP_PROBE5(connect__established, NULL, tp,
9391 			    mtod(m, const char *), tp, th);
9392 			rack_cc_conn_init(tp);
9393 		}
9394 	} else {
9395 		/*
9396 		 * Received initial SYN in SYN-SENT[*] state => simultaneous
9397 		 * open.  If segment contains CC option and there is a
9398 		 * cached CC, apply TAO test. If it succeeds, connection is *
9399 		 * half-synchronized. Otherwise, do 3-way handshake:
9400 		 * SYN-SENT -> SYN-RECEIVED SYN-SENT* -> SYN-RECEIVED* If
9401 		 * there was no CC option, clear cached CC value.
9402 		 */
9403 		tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
9404 		tcp_state_change(tp, TCPS_SYN_RECEIVED);
9405 	}
9406 	INP_WLOCK_ASSERT(tp->t_inpcb);
9407 	/*
9408 	 * Advance th->th_seq to correspond to first data byte. If data,
9409 	 * trim to stay within window, dropping FIN if necessary.
9410 	 */
9411 	th->th_seq++;
9412 	if (tlen > tp->rcv_wnd) {
9413 		todrop = tlen - tp->rcv_wnd;
9414 		m_adj(m, -todrop);
9415 		tlen = tp->rcv_wnd;
9416 		thflags &= ~TH_FIN;
9417 		KMOD_TCPSTAT_INC(tcps_rcvpackafterwin);
9418 		KMOD_TCPSTAT_ADD(tcps_rcvbyteafterwin, todrop);
9419 	}
9420 	tp->snd_wl1 = th->th_seq - 1;
9421 	tp->rcv_up = th->th_seq;
9422 	/*
9423 	 * Client side of transaction: already sent SYN and data. If the
9424 	 * remote host used T/TCP to validate the SYN, our data will be
9425 	 * ACK'd; if so, enter normal data segment processing in the middle
9426 	 * of step 5, ack processing. Otherwise, goto step 6.
9427 	 */
9428 	if (thflags & TH_ACK) {
9429 		/* For syn-sent we need to possibly update the rtt */
9430 		if ((to->to_flags & TOF_TS) != 0 && to->to_tsecr) {
9431 			uint32_t t;
9432 
9433 			t = tcp_ts_getticks() - to->to_tsecr;
9434 			if (!tp->t_rttlow || tp->t_rttlow > t)
9435 				tp->t_rttlow = t;
9436 			tcp_rack_xmit_timer(rack, t + 1, 1, (t * HPTS_USEC_IN_MSEC), 0, NULL, 2);
9437 			tcp_rack_xmit_timer_commit(rack, tp);
9438 		}
9439 		if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val))
9440 			return (ret_val);
9441 		/* We may have changed to FIN_WAIT_1 above */
9442 		if (tp->t_state == TCPS_FIN_WAIT_1) {
9443 			/*
9444 			 * In FIN_WAIT_1 STATE in addition to the processing
9445 			 * for the ESTABLISHED state if our FIN is now
9446 			 * acknowledged then enter FIN_WAIT_2.
9447 			 */
9448 			if (ourfinisacked) {
9449 				/*
9450 				 * If we can't receive any more data, then
9451 				 * closing user can proceed. Starting the
9452 				 * timer is contrary to the specification,
9453 				 * but if we don't get a FIN we'll hang
9454 				 * forever.
9455 				 *
9456 				 * XXXjl: we should release the tp also, and
9457 				 * use a compressed state.
9458 				 */
9459 				if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9460 					soisdisconnected(so);
9461 					tcp_timer_activate(tp, TT_2MSL,
9462 					    (tcp_fast_finwait2_recycle ?
9463 					    tcp_finwait2_timeout :
9464 					    TP_MAXIDLE(tp)));
9465 				}
9466 				tcp_state_change(tp, TCPS_FIN_WAIT_2);
9467 			}
9468 		}
9469 	}
9470 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9471 	   tiwin, thflags, nxt_pkt));
9472 }
9473 
9474 /*
9475  * Return value of 1, the TCB is unlocked and most
9476  * likely gone, return value of 0, the TCP is still
9477  * locked.
9478  */
9479 static int
9480 rack_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct socket *so,
9481     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9482     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9483 {
9484 	struct tcp_rack *rack;
9485 	int32_t ret_val = 0;
9486 	int32_t ourfinisacked = 0;
9487 
9488 	ctf_calc_rwin(so, tp);
9489 	if ((thflags & TH_ACK) &&
9490 	    (SEQ_LEQ(th->th_ack, tp->snd_una) ||
9491 	    SEQ_GT(th->th_ack, tp->snd_max))) {
9492 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9493 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9494 		return (1);
9495 	}
9496 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9497 	if (IS_FASTOPEN(tp->t_flags)) {
9498 		/*
9499 		 * When a TFO connection is in SYN_RECEIVED, the
9500 		 * only valid packets are the initial SYN, a
9501 		 * retransmit/copy of the initial SYN (possibly with
9502 		 * a subset of the original data), a valid ACK, a
9503 		 * FIN, or a RST.
9504 		 */
9505 		if ((thflags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) {
9506 			tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9507 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9508 			return (1);
9509 		} else if (thflags & TH_SYN) {
9510 			/* non-initial SYN is ignored */
9511 			if ((rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT) ||
9512 			    (rack->r_ctl.rc_hpts_flags & PACE_TMR_TLP) ||
9513 			    (rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK)) {
9514 				ctf_do_drop(m, NULL);
9515 				return (0);
9516 			}
9517 		} else if (!(thflags & (TH_ACK | TH_FIN | TH_RST))) {
9518 			ctf_do_drop(m, NULL);
9519 			return (0);
9520 		}
9521 	}
9522 	if ((thflags & TH_RST) ||
9523 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9524 		return (ctf_process_rst(m, th, so, tp));
9525 	/*
9526 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9527 	 * it's less than ts_recent, drop it.
9528 	 */
9529 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9530 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9531 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9532 			return (ret_val);
9533 	}
9534 	/*
9535 	 * In the SYN-RECEIVED state, validate that the packet belongs to
9536 	 * this connection before trimming the data to fit the receive
9537 	 * window.  Check the sequence number versus IRS since we know the
9538 	 * sequence numbers haven't wrapped.  This is a partial fix for the
9539 	 * "LAND" DoS attack.
9540 	 */
9541 	if (SEQ_LT(th->th_seq, tp->irs)) {
9542 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9543 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9544 		return (1);
9545 	}
9546 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9547 		return (ret_val);
9548 	}
9549 	/*
9550 	 * If last ACK falls within this segment's sequence numbers, record
9551 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9552 	 * from the latest proposal of the tcplw@cray.com list (Braden
9553 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9554 	 * with our earlier PAWS tests, so this check should be solely
9555 	 * predicated on the sequence space of this segment. 3) That we
9556 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9557 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9558 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9559 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9560 	 * p.869. In such cases, we can still calculate the RTT correctly
9561 	 * when RCV.NXT == Last.ACK.Sent.
9562 	 */
9563 	if ((to->to_flags & TOF_TS) != 0 &&
9564 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9565 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9566 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9567 		tp->ts_recent_age = tcp_ts_getticks();
9568 		tp->ts_recent = to->to_tsval;
9569 	}
9570 	tp->snd_wnd = tiwin;
9571 	/*
9572 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9573 	 * is on (half-synchronized state), then queue data for later
9574 	 * processing; else drop segment and return.
9575 	 */
9576 	if ((thflags & TH_ACK) == 0) {
9577 		if (IS_FASTOPEN(tp->t_flags)) {
9578 			rack_cc_conn_init(tp);
9579 		}
9580 		return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9581 		    tiwin, thflags, nxt_pkt));
9582 	}
9583 	KMOD_TCPSTAT_INC(tcps_connects);
9584 	soisconnected(so);
9585 	/* Do window scaling? */
9586 	if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
9587 	    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
9588 		tp->rcv_scale = tp->request_r_scale;
9589 	}
9590 	/*
9591 	 * Make transitions: SYN-RECEIVED  -> ESTABLISHED SYN-RECEIVED* ->
9592 	 * FIN-WAIT-1
9593 	 */
9594 	tp->t_starttime = ticks;
9595 	if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
9596 		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
9597 		tp->t_tfo_pending = NULL;
9598 	}
9599 	if (tp->t_flags & TF_NEEDFIN) {
9600 		tcp_state_change(tp, TCPS_FIN_WAIT_1);
9601 		tp->t_flags &= ~TF_NEEDFIN;
9602 	} else {
9603 		tcp_state_change(tp, TCPS_ESTABLISHED);
9604 		TCP_PROBE5(accept__established, NULL, tp,
9605 		    mtod(m, const char *), tp, th);
9606 		/*
9607 		 * TFO connections call cc_conn_init() during SYN
9608 		 * processing.  Calling it again here for such connections
9609 		 * is not harmless as it would undo the snd_cwnd reduction
9610 		 * that occurs when a TFO SYN|ACK is retransmitted.
9611 		 */
9612 		if (!IS_FASTOPEN(tp->t_flags))
9613 			rack_cc_conn_init(tp);
9614 	}
9615 	/*
9616 	 * Account for the ACK of our SYN prior to
9617 	 * regular ACK processing below, except for
9618 	 * simultaneous SYN, which is handled later.
9619 	 */
9620 	if (SEQ_GT(th->th_ack, tp->snd_una) && !(tp->t_flags & TF_NEEDSYN))
9621 		tp->snd_una++;
9622 	/*
9623 	 * If segment contains data or ACK, will call tcp_reass() later; if
9624 	 * not, do so now to pass queued data to user.
9625 	 */
9626 	if (tlen == 0 && (thflags & TH_FIN) == 0)
9627 		(void) tcp_reass(tp, (struct tcphdr *)0, NULL, 0,
9628 		    (struct mbuf *)0);
9629 	tp->snd_wl1 = th->th_seq - 1;
9630 	/* For syn-recv we need to possibly update the rtt */
9631 	if ((to->to_flags & TOF_TS) != 0 && to->to_tsecr) {
9632 		uint32_t t;
9633 
9634 		t = tcp_ts_getticks() - to->to_tsecr;
9635 		if (!tp->t_rttlow || tp->t_rttlow > t)
9636 			tp->t_rttlow = t;
9637 		tcp_rack_xmit_timer(rack, t + 1, 1, (t * HPTS_USEC_IN_MSEC), 0, NULL, 2);
9638 		tcp_rack_xmit_timer_commit(rack, tp);
9639 	}
9640 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9641 		return (ret_val);
9642 	}
9643 	if (tp->t_state == TCPS_FIN_WAIT_1) {
9644 		/* We could have went to FIN_WAIT_1 (or EST) above */
9645 		/*
9646 		 * In FIN_WAIT_1 STATE in addition to the processing for the
9647 		 * ESTABLISHED state if our FIN is now acknowledged then
9648 		 * enter FIN_WAIT_2.
9649 		 */
9650 		if (ourfinisacked) {
9651 			/*
9652 			 * If we can't receive any more data, then closing
9653 			 * user can proceed. Starting the timer is contrary
9654 			 * to the specification, but if we don't get a FIN
9655 			 * we'll hang forever.
9656 			 *
9657 			 * XXXjl: we should release the tp also, and use a
9658 			 * compressed state.
9659 			 */
9660 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9661 				soisdisconnected(so);
9662 				tcp_timer_activate(tp, TT_2MSL,
9663 				    (tcp_fast_finwait2_recycle ?
9664 				    tcp_finwait2_timeout :
9665 				    TP_MAXIDLE(tp)));
9666 			}
9667 			tcp_state_change(tp, TCPS_FIN_WAIT_2);
9668 		}
9669 	}
9670 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9671 	    tiwin, thflags, nxt_pkt));
9672 }
9673 
9674 /*
9675  * Return value of 1, the TCB is unlocked and most
9676  * likely gone, return value of 0, the TCP is still
9677  * locked.
9678  */
9679 static int
9680 rack_do_established(struct mbuf *m, struct tcphdr *th, struct socket *so,
9681     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9682     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9683 {
9684 	int32_t ret_val = 0;
9685 	struct tcp_rack *rack;
9686 
9687 	/*
9688 	 * Header prediction: check for the two common cases of a
9689 	 * uni-directional data xfer.  If the packet has no control flags,
9690 	 * is in-sequence, the window didn't change and we're not
9691 	 * retransmitting, it's a candidate.  If the length is zero and the
9692 	 * ack moved forward, we're the sender side of the xfer.  Just free
9693 	 * the data acked & wake any higher level process that was blocked
9694 	 * waiting for space.  If the length is non-zero and the ack didn't
9695 	 * move, we're the receiver side.  If we're getting packets in-order
9696 	 * (the reassembly queue is empty), add the data toc The socket
9697 	 * buffer and note that we need a delayed ack. Make sure that the
9698 	 * hidden state-flags are also off. Since we check for
9699 	 * TCPS_ESTABLISHED first, it can only be TH_NEEDSYN.
9700 	 */
9701 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9702 	if (__predict_true(((to->to_flags & TOF_SACK) == 0)) &&
9703 	    __predict_true((thflags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) == TH_ACK) &&
9704 	    __predict_true(SEGQ_EMPTY(tp)) &&
9705 	    __predict_true(th->th_seq == tp->rcv_nxt)) {
9706 		if (tlen == 0) {
9707 			if (rack_fastack(m, th, so, tp, to, drop_hdrlen, tlen,
9708 			    tiwin, nxt_pkt, rack->r_ctl.rc_rcvtime)) {
9709 				return (0);
9710 			}
9711 		} else {
9712 			if (rack_do_fastnewdata(m, th, so, tp, to, drop_hdrlen, tlen,
9713 			    tiwin, nxt_pkt, iptos)) {
9714 				return (0);
9715 			}
9716 		}
9717 	}
9718 	ctf_calc_rwin(so, tp);
9719 
9720 	if ((thflags & TH_RST) ||
9721 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9722 		return (ctf_process_rst(m, th, so, tp));
9723 
9724 	/*
9725 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9726 	 * synchronized state.
9727 	 */
9728 	if (thflags & TH_SYN) {
9729 		ctf_challenge_ack(m, th, tp, &ret_val);
9730 		return (ret_val);
9731 	}
9732 	/*
9733 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9734 	 * it's less than ts_recent, drop it.
9735 	 */
9736 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9737 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9738 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9739 			return (ret_val);
9740 	}
9741 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9742 		return (ret_val);
9743 	}
9744 	/*
9745 	 * If last ACK falls within this segment's sequence numbers, record
9746 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9747 	 * from the latest proposal of the tcplw@cray.com list (Braden
9748 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9749 	 * with our earlier PAWS tests, so this check should be solely
9750 	 * predicated on the sequence space of this segment. 3) That we
9751 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9752 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9753 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9754 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9755 	 * p.869. In such cases, we can still calculate the RTT correctly
9756 	 * when RCV.NXT == Last.ACK.Sent.
9757 	 */
9758 	if ((to->to_flags & TOF_TS) != 0 &&
9759 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9760 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9761 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9762 		tp->ts_recent_age = tcp_ts_getticks();
9763 		tp->ts_recent = to->to_tsval;
9764 	}
9765 	/*
9766 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9767 	 * is on (half-synchronized state), then queue data for later
9768 	 * processing; else drop segment and return.
9769 	 */
9770 	if ((thflags & TH_ACK) == 0) {
9771 		if (tp->t_flags & TF_NEEDSYN) {
9772 
9773 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9774 			    tiwin, thflags, nxt_pkt));
9775 
9776 		} else if (tp->t_flags & TF_ACKNOW) {
9777 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9778 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output= 1;
9779 			return (ret_val);
9780 		} else {
9781 			ctf_do_drop(m, NULL);
9782 			return (0);
9783 		}
9784 	}
9785 	/*
9786 	 * Ack processing.
9787 	 */
9788 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
9789 		return (ret_val);
9790 	}
9791 	if (sbavail(&so->so_snd)) {
9792 		if (ctf_progress_timeout_check(tp, true)) {
9793 			rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
9794 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
9795 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9796 			return (1);
9797 		}
9798 	}
9799 	/* State changes only happen in rack_process_data() */
9800 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9801 	    tiwin, thflags, nxt_pkt));
9802 }
9803 
9804 /*
9805  * Return value of 1, the TCB is unlocked and most
9806  * likely gone, return value of 0, the TCP is still
9807  * locked.
9808  */
9809 static int
9810 rack_do_close_wait(struct mbuf *m, struct tcphdr *th, struct socket *so,
9811     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9812     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9813 {
9814 	int32_t ret_val = 0;
9815 
9816 	ctf_calc_rwin(so, tp);
9817 	if ((thflags & TH_RST) ||
9818 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9819 		return (ctf_process_rst(m, th, so, tp));
9820 	/*
9821 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9822 	 * synchronized state.
9823 	 */
9824 	if (thflags & TH_SYN) {
9825 		ctf_challenge_ack(m, th, tp, &ret_val);
9826 		return (ret_val);
9827 	}
9828 	/*
9829 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9830 	 * it's less than ts_recent, drop it.
9831 	 */
9832 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9833 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9834 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9835 			return (ret_val);
9836 	}
9837 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9838 		return (ret_val);
9839 	}
9840 	/*
9841 	 * If last ACK falls within this segment's sequence numbers, record
9842 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9843 	 * from the latest proposal of the tcplw@cray.com list (Braden
9844 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9845 	 * with our earlier PAWS tests, so this check should be solely
9846 	 * predicated on the sequence space of this segment. 3) That we
9847 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9848 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9849 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9850 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9851 	 * p.869. In such cases, we can still calculate the RTT correctly
9852 	 * when RCV.NXT == Last.ACK.Sent.
9853 	 */
9854 	if ((to->to_flags & TOF_TS) != 0 &&
9855 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9856 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9857 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9858 		tp->ts_recent_age = tcp_ts_getticks();
9859 		tp->ts_recent = to->to_tsval;
9860 	}
9861 	/*
9862 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9863 	 * is on (half-synchronized state), then queue data for later
9864 	 * processing; else drop segment and return.
9865 	 */
9866 	if ((thflags & TH_ACK) == 0) {
9867 		if (tp->t_flags & TF_NEEDSYN) {
9868 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9869 			    tiwin, thflags, nxt_pkt));
9870 
9871 		} else if (tp->t_flags & TF_ACKNOW) {
9872 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9873 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
9874 			return (ret_val);
9875 		} else {
9876 			ctf_do_drop(m, NULL);
9877 			return (0);
9878 		}
9879 	}
9880 	/*
9881 	 * Ack processing.
9882 	 */
9883 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
9884 		return (ret_val);
9885 	}
9886 	if (sbavail(&so->so_snd)) {
9887 		if (ctf_progress_timeout_check(tp, true)) {
9888 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
9889 						tp, tick, PROGRESS_DROP, __LINE__);
9890 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
9891 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9892 			return (1);
9893 		}
9894 	}
9895 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9896 	    tiwin, thflags, nxt_pkt));
9897 }
9898 
9899 static int
9900 rack_check_data_after_close(struct mbuf *m,
9901     struct tcpcb *tp, int32_t *tlen, struct tcphdr *th, struct socket *so)
9902 {
9903 	struct tcp_rack *rack;
9904 
9905 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9906 	if (rack->rc_allow_data_af_clo == 0) {
9907 	close_now:
9908 		tcp_log_end_status(tp, TCP_EI_STATUS_DATA_A_CLOSE);
9909 		/* tcp_close will kill the inp pre-log the Reset */
9910 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
9911 		tp = tcp_close(tp);
9912 		KMOD_TCPSTAT_INC(tcps_rcvafterclose);
9913 		ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, (*tlen));
9914 		return (1);
9915 	}
9916 	if (sbavail(&so->so_snd) == 0)
9917 		goto close_now;
9918 	/* Ok we allow data that is ignored and a followup reset */
9919 	tcp_log_end_status(tp, TCP_EI_STATUS_DATA_A_CLOSE);
9920 	tp->rcv_nxt = th->th_seq + *tlen;
9921 	tp->t_flags2 |= TF2_DROP_AF_DATA;
9922 	rack->r_wanted_output = 1;
9923 	*tlen = 0;
9924 	return (0);
9925 }
9926 
9927 /*
9928  * Return value of 1, the TCB is unlocked and most
9929  * likely gone, return value of 0, the TCP is still
9930  * locked.
9931  */
9932 static int
9933 rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th, struct socket *so,
9934     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9935     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9936 {
9937 	int32_t ret_val = 0;
9938 	int32_t ourfinisacked = 0;
9939 
9940 	ctf_calc_rwin(so, tp);
9941 
9942 	if ((thflags & TH_RST) ||
9943 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9944 		return (ctf_process_rst(m, th, so, tp));
9945 	/*
9946 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9947 	 * synchronized state.
9948 	 */
9949 	if (thflags & TH_SYN) {
9950 		ctf_challenge_ack(m, th, tp, &ret_val);
9951 		return (ret_val);
9952 	}
9953 	/*
9954 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9955 	 * it's less than ts_recent, drop it.
9956 	 */
9957 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9958 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9959 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9960 			return (ret_val);
9961 	}
9962 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9963 		return (ret_val);
9964 	}
9965 	/*
9966 	 * If new data are received on a connection after the user processes
9967 	 * are gone, then RST the other end.
9968 	 */
9969 	if ((so->so_state & SS_NOFDREF) && tlen) {
9970 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
9971 			return (1);
9972 	}
9973 	/*
9974 	 * If last ACK falls within this segment's sequence numbers, record
9975 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9976 	 * from the latest proposal of the tcplw@cray.com list (Braden
9977 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9978 	 * with our earlier PAWS tests, so this check should be solely
9979 	 * predicated on the sequence space of this segment. 3) That we
9980 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9981 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9982 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9983 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9984 	 * p.869. In such cases, we can still calculate the RTT correctly
9985 	 * when RCV.NXT == Last.ACK.Sent.
9986 	 */
9987 	if ((to->to_flags & TOF_TS) != 0 &&
9988 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9989 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9990 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9991 		tp->ts_recent_age = tcp_ts_getticks();
9992 		tp->ts_recent = to->to_tsval;
9993 	}
9994 	/*
9995 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9996 	 * is on (half-synchronized state), then queue data for later
9997 	 * processing; else drop segment and return.
9998 	 */
9999 	if ((thflags & TH_ACK) == 0) {
10000 		if (tp->t_flags & TF_NEEDSYN) {
10001 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10002 			    tiwin, thflags, nxt_pkt));
10003 		} else if (tp->t_flags & TF_ACKNOW) {
10004 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
10005 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
10006 			return (ret_val);
10007 		} else {
10008 			ctf_do_drop(m, NULL);
10009 			return (0);
10010 		}
10011 	}
10012 	/*
10013 	 * Ack processing.
10014 	 */
10015 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
10016 		return (ret_val);
10017 	}
10018 	if (ourfinisacked) {
10019 		/*
10020 		 * If we can't receive any more data, then closing user can
10021 		 * proceed. Starting the timer is contrary to the
10022 		 * specification, but if we don't get a FIN we'll hang
10023 		 * forever.
10024 		 *
10025 		 * XXXjl: we should release the tp also, and use a
10026 		 * compressed state.
10027 		 */
10028 		if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
10029 			soisdisconnected(so);
10030 			tcp_timer_activate(tp, TT_2MSL,
10031 			    (tcp_fast_finwait2_recycle ?
10032 			    tcp_finwait2_timeout :
10033 			    TP_MAXIDLE(tp)));
10034 		}
10035 		tcp_state_change(tp, TCPS_FIN_WAIT_2);
10036 	}
10037 	if (sbavail(&so->so_snd)) {
10038 		if (ctf_progress_timeout_check(tp, true)) {
10039 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
10040 						tp, tick, PROGRESS_DROP, __LINE__);
10041 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
10042 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
10043 			return (1);
10044 		}
10045 	}
10046 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10047 	    tiwin, thflags, nxt_pkt));
10048 }
10049 
10050 /*
10051  * Return value of 1, the TCB is unlocked and most
10052  * likely gone, return value of 0, the TCP is still
10053  * locked.
10054  */
10055 static int
10056 rack_do_closing(struct mbuf *m, struct tcphdr *th, struct socket *so,
10057     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
10058     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
10059 {
10060 	int32_t ret_val = 0;
10061 	int32_t ourfinisacked = 0;
10062 
10063 	ctf_calc_rwin(so, tp);
10064 
10065 	if ((thflags & TH_RST) ||
10066 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
10067 		return (ctf_process_rst(m, th, so, tp));
10068 	/*
10069 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
10070 	 * synchronized state.
10071 	 */
10072 	if (thflags & TH_SYN) {
10073 		ctf_challenge_ack(m, th, tp, &ret_val);
10074 		return (ret_val);
10075 	}
10076 	/*
10077 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
10078 	 * it's less than ts_recent, drop it.
10079 	 */
10080 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
10081 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
10082 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
10083 			return (ret_val);
10084 	}
10085 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
10086 		return (ret_val);
10087 	}
10088 	/*
10089 	 * If new data are received on a connection after the user processes
10090 	 * are gone, then RST the other end.
10091 	 */
10092 	if ((so->so_state & SS_NOFDREF) && tlen) {
10093 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
10094 			return (1);
10095 	}
10096 	/*
10097 	 * If last ACK falls within this segment's sequence numbers, record
10098 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
10099 	 * from the latest proposal of the tcplw@cray.com list (Braden
10100 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
10101 	 * with our earlier PAWS tests, so this check should be solely
10102 	 * predicated on the sequence space of this segment. 3) That we
10103 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
10104 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
10105 	 * SEG.Len, This modified check allows us to overcome RFC1323's
10106 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
10107 	 * p.869. In such cases, we can still calculate the RTT correctly
10108 	 * when RCV.NXT == Last.ACK.Sent.
10109 	 */
10110 	if ((to->to_flags & TOF_TS) != 0 &&
10111 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
10112 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
10113 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
10114 		tp->ts_recent_age = tcp_ts_getticks();
10115 		tp->ts_recent = to->to_tsval;
10116 	}
10117 	/*
10118 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
10119 	 * is on (half-synchronized state), then queue data for later
10120 	 * processing; else drop segment and return.
10121 	 */
10122 	if ((thflags & TH_ACK) == 0) {
10123 		if (tp->t_flags & TF_NEEDSYN) {
10124 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10125 			    tiwin, thflags, nxt_pkt));
10126 		} else if (tp->t_flags & TF_ACKNOW) {
10127 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
10128 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output= 1;
10129 			return (ret_val);
10130 		} else {
10131 			ctf_do_drop(m, NULL);
10132 			return (0);
10133 		}
10134 	}
10135 	/*
10136 	 * Ack processing.
10137 	 */
10138 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
10139 		return (ret_val);
10140 	}
10141 	if (ourfinisacked) {
10142 		tcp_twstart(tp);
10143 		m_freem(m);
10144 		return (1);
10145 	}
10146 	if (sbavail(&so->so_snd)) {
10147 		if (ctf_progress_timeout_check(tp, true)) {
10148 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
10149 						tp, tick, PROGRESS_DROP, __LINE__);
10150 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
10151 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
10152 			return (1);
10153 		}
10154 	}
10155 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10156 	    tiwin, thflags, nxt_pkt));
10157 }
10158 
10159 /*
10160  * Return value of 1, the TCB is unlocked and most
10161  * likely gone, return value of 0, the TCP is still
10162  * locked.
10163  */
10164 static int
10165 rack_do_lastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
10166     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
10167     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
10168 {
10169 	int32_t ret_val = 0;
10170 	int32_t ourfinisacked = 0;
10171 
10172 	ctf_calc_rwin(so, tp);
10173 
10174 	if ((thflags & TH_RST) ||
10175 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
10176 		return (ctf_process_rst(m, th, so, tp));
10177 	/*
10178 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
10179 	 * synchronized state.
10180 	 */
10181 	if (thflags & TH_SYN) {
10182 		ctf_challenge_ack(m, th, tp, &ret_val);
10183 		return (ret_val);
10184 	}
10185 	/*
10186 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
10187 	 * it's less than ts_recent, drop it.
10188 	 */
10189 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
10190 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
10191 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
10192 			return (ret_val);
10193 	}
10194 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
10195 		return (ret_val);
10196 	}
10197 	/*
10198 	 * If new data are received on a connection after the user processes
10199 	 * are gone, then RST the other end.
10200 	 */
10201 	if ((so->so_state & SS_NOFDREF) && tlen) {
10202 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
10203 			return (1);
10204 	}
10205 	/*
10206 	 * If last ACK falls within this segment's sequence numbers, record
10207 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
10208 	 * from the latest proposal of the tcplw@cray.com list (Braden
10209 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
10210 	 * with our earlier PAWS tests, so this check should be solely
10211 	 * predicated on the sequence space of this segment. 3) That we
10212 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
10213 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
10214 	 * SEG.Len, This modified check allows us to overcome RFC1323's
10215 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
10216 	 * p.869. In such cases, we can still calculate the RTT correctly
10217 	 * when RCV.NXT == Last.ACK.Sent.
10218 	 */
10219 	if ((to->to_flags & TOF_TS) != 0 &&
10220 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
10221 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
10222 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
10223 		tp->ts_recent_age = tcp_ts_getticks();
10224 		tp->ts_recent = to->to_tsval;
10225 	}
10226 	/*
10227 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
10228 	 * is on (half-synchronized state), then queue data for later
10229 	 * processing; else drop segment and return.
10230 	 */
10231 	if ((thflags & TH_ACK) == 0) {
10232 		if (tp->t_flags & TF_NEEDSYN) {
10233 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10234 			    tiwin, thflags, nxt_pkt));
10235 		} else if (tp->t_flags & TF_ACKNOW) {
10236 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
10237 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
10238 			return (ret_val);
10239 		} else {
10240 			ctf_do_drop(m, NULL);
10241 			return (0);
10242 		}
10243 	}
10244 	/*
10245 	 * case TCPS_LAST_ACK: Ack processing.
10246 	 */
10247 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
10248 		return (ret_val);
10249 	}
10250 	if (ourfinisacked) {
10251 		tp = tcp_close(tp);
10252 		ctf_do_drop(m, tp);
10253 		return (1);
10254 	}
10255 	if (sbavail(&so->so_snd)) {
10256 		if (ctf_progress_timeout_check(tp, true)) {
10257 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
10258 						tp, tick, PROGRESS_DROP, __LINE__);
10259 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
10260 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
10261 			return (1);
10262 		}
10263 	}
10264 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10265 	    tiwin, thflags, nxt_pkt));
10266 }
10267 
10268 
10269 /*
10270  * Return value of 1, the TCB is unlocked and most
10271  * likely gone, return value of 0, the TCP is still
10272  * locked.
10273  */
10274 static int
10275 rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th, struct socket *so,
10276     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
10277     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
10278 {
10279 	int32_t ret_val = 0;
10280 	int32_t ourfinisacked = 0;
10281 
10282 	ctf_calc_rwin(so, tp);
10283 
10284 	/* Reset receive buffer auto scaling when not in bulk receive mode. */
10285 	if ((thflags & TH_RST) ||
10286 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
10287 		return (ctf_process_rst(m, th, so, tp));
10288 	/*
10289 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
10290 	 * synchronized state.
10291 	 */
10292 	if (thflags & TH_SYN) {
10293 		ctf_challenge_ack(m, th, tp, &ret_val);
10294 		return (ret_val);
10295 	}
10296 	/*
10297 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
10298 	 * it's less than ts_recent, drop it.
10299 	 */
10300 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
10301 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
10302 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
10303 			return (ret_val);
10304 	}
10305 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
10306 		return (ret_val);
10307 	}
10308 	/*
10309 	 * If new data are received on a connection after the user processes
10310 	 * are gone, then RST the other end.
10311 	 */
10312 	if ((so->so_state & SS_NOFDREF) &&
10313 	    tlen) {
10314 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
10315 			return (1);
10316 	}
10317 	/*
10318 	 * If last ACK falls within this segment's sequence numbers, record
10319 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
10320 	 * from the latest proposal of the tcplw@cray.com list (Braden
10321 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
10322 	 * with our earlier PAWS tests, so this check should be solely
10323 	 * predicated on the sequence space of this segment. 3) That we
10324 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
10325 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
10326 	 * SEG.Len, This modified check allows us to overcome RFC1323's
10327 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
10328 	 * p.869. In such cases, we can still calculate the RTT correctly
10329 	 * when RCV.NXT == Last.ACK.Sent.
10330 	 */
10331 	if ((to->to_flags & TOF_TS) != 0 &&
10332 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
10333 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
10334 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
10335 		tp->ts_recent_age = tcp_ts_getticks();
10336 		tp->ts_recent = to->to_tsval;
10337 	}
10338 	/*
10339 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
10340 	 * is on (half-synchronized state), then queue data for later
10341 	 * processing; else drop segment and return.
10342 	 */
10343 	if ((thflags & TH_ACK) == 0) {
10344 		if (tp->t_flags & TF_NEEDSYN) {
10345 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10346 			    tiwin, thflags, nxt_pkt));
10347 		} else if (tp->t_flags & TF_ACKNOW) {
10348 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
10349 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
10350 			return (ret_val);
10351 		} else {
10352 			ctf_do_drop(m, NULL);
10353 			return (0);
10354 		}
10355 	}
10356 	/*
10357 	 * Ack processing.
10358 	 */
10359 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
10360 		return (ret_val);
10361 	}
10362 	if (sbavail(&so->so_snd)) {
10363 		if (ctf_progress_timeout_check(tp, true)) {
10364 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
10365 						tp, tick, PROGRESS_DROP, __LINE__);
10366 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
10367 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
10368 			return (1);
10369 		}
10370 	}
10371 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10372 	    tiwin, thflags, nxt_pkt));
10373 }
10374 
10375 static void inline
10376 rack_clear_rate_sample(struct tcp_rack *rack)
10377 {
10378 	rack->r_ctl.rack_rs.rs_flags = RACK_RTT_EMPTY;
10379 	rack->r_ctl.rack_rs.rs_rtt_cnt = 0;
10380 	rack->r_ctl.rack_rs.rs_rtt_tot = 0;
10381 }
10382 
10383 static void
10384 rack_set_pace_segments(struct tcpcb *tp, struct tcp_rack *rack, uint32_t line)
10385 {
10386 	uint64_t bw_est, rate_wanted;
10387 	uint32_t tls_seg = 0;
10388 	int chged = 0;
10389 	uint32_t user_max;
10390 
10391 	user_max = ctf_fixed_maxseg(tp) * rack->rc_user_set_max_segs;
10392 #ifdef KERN_TLS
10393 	if (rack->rc_inp->inp_socket->so_snd.sb_flags & SB_TLS_IFNET) {
10394 		tls_seg = ctf_get_opt_tls_size(rack->rc_inp->inp_socket, rack->rc_tp->snd_wnd);
10395 		if (tls_seg != rack->r_ctl.rc_pace_min_segs)
10396 			chged = 1;
10397 		rack->r_ctl.rc_pace_min_segs = tls_seg;
10398 	} else
10399 #endif
10400 	{
10401 		if (ctf_fixed_maxseg(tp) != rack->r_ctl.rc_pace_min_segs)
10402 			chged = 1;
10403 		rack->r_ctl.rc_pace_min_segs = ctf_fixed_maxseg(tp);
10404 	}
10405 	if (rack->use_fixed_rate || rack->rc_force_max_seg) {
10406 		if (user_max != rack->r_ctl.rc_pace_max_segs)
10407 			chged = 1;
10408 	}
10409 	if (rack->rc_force_max_seg) {
10410 		rack->r_ctl.rc_pace_max_segs = user_max;
10411 	} else if (rack->use_fixed_rate) {
10412 		bw_est = rack_get_bw(rack);
10413 		if ((rack->r_ctl.crte == NULL) ||
10414 		    (bw_est != rack->r_ctl.crte->rate))  {
10415 			rack->r_ctl.rc_pace_max_segs = user_max;
10416 		} else {
10417 			/* We are pacing right at the hardware rate */
10418 			uint32_t segsiz;
10419 
10420 			segsiz = min(ctf_fixed_maxseg(tp),
10421 				     rack->r_ctl.rc_pace_min_segs);
10422 			rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(
10423 				                           bw_est, segsiz, 0,
10424 							   rack->r_ctl.crte, NULL);
10425 		}
10426 	} else if (rack->rc_always_pace) {
10427 		if (rack->r_ctl.gp_bw ||
10428 #ifdef NETFLIX_PEAKRATE
10429 		    rack->rc_tp->t_maxpeakrate ||
10430 #endif
10431 		    rack->r_ctl.init_rate) {
10432 			/* We have a rate of some sort set */
10433 			uint32_t  orig;
10434 
10435 			bw_est = rack_get_bw(rack);
10436 			orig = rack->r_ctl.rc_pace_max_segs;
10437 			rate_wanted = rack_get_output_bw(rack, bw_est, NULL);
10438 			if (rate_wanted) {
10439 				/* We have something */
10440 				rack->r_ctl.rc_pace_max_segs = rack_get_pacing_len(rack,
10441 										   rate_wanted,
10442 										   ctf_fixed_maxseg(rack->rc_tp));
10443 			} else
10444 				rack->r_ctl.rc_pace_max_segs = rack->r_ctl.rc_pace_min_segs;
10445 			if (orig != rack->r_ctl.rc_pace_max_segs)
10446 				chged = 1;
10447 		} else if ((rack->r_ctl.gp_bw == 0) &&
10448 			   (rack->r_ctl.rc_pace_max_segs == 0)) {
10449 			/*
10450 			 * If we have nothing limit us to bursting
10451 			 * out IW sized pieces.
10452 			 */
10453 			chged = 1;
10454 			rack->r_ctl.rc_pace_max_segs = rc_init_window(rack);
10455 		}
10456 	}
10457 	if (rack->r_ctl.rc_pace_max_segs > PACE_MAX_IP_BYTES) {
10458 		chged = 1;
10459 		rack->r_ctl.rc_pace_max_segs = PACE_MAX_IP_BYTES;
10460 	}
10461 #ifdef KERN_TLS
10462 	uint32_t orig;
10463 
10464 	if (tls_seg != 0) {
10465 		orig = rack->r_ctl.rc_pace_max_segs;
10466 		if (rack_hw_tls_max_seg > 1) {
10467 			rack->r_ctl.rc_pace_max_segs /= tls_seg;
10468 			if (rack_hw_tls_max_seg > rack->r_ctl.rc_pace_max_segs)
10469 				rack->r_ctl.rc_pace_max_segs = rack_hw_tls_max_seg;
10470 		} else {
10471 			rack->r_ctl.rc_pace_max_segs = 1;
10472 		}
10473 		if (rack->r_ctl.rc_pace_max_segs == 0)
10474 			rack->r_ctl.rc_pace_max_segs = 1;
10475 		rack->r_ctl.rc_pace_max_segs *= tls_seg;
10476 		if (rack->r_ctl.rc_pace_max_segs > PACE_MAX_IP_BYTES) {
10477 			/* We can't go over the max bytes (usually 64k) */
10478 			rack->r_ctl.rc_pace_max_segs = ((PACE_MAX_IP_BYTES / tls_seg) * tls_seg);
10479 		}
10480 		if (orig != rack->r_ctl.rc_pace_max_segs)
10481 			chged = 1;
10482 	}
10483 #endif
10484 	if (chged)
10485 		rack_log_type_hrdwtso(tp, rack, tls_seg, rack->rc_inp->inp_socket->so_snd.sb_flags, line, 2);
10486 }
10487 
10488 static int
10489 rack_init(struct tcpcb *tp)
10490 {
10491 	struct tcp_rack *rack = NULL;
10492 	struct rack_sendmap *insret;
10493 	uint32_t iwin, snt, us_cts;
10494 
10495 	tp->t_fb_ptr = uma_zalloc(rack_pcb_zone, M_NOWAIT);
10496 	if (tp->t_fb_ptr == NULL) {
10497 		/*
10498 		 * We need to allocate memory but cant. The INP and INP_INFO
10499 		 * locks and they are recusive (happens during setup. So a
10500 		 * scheme to drop the locks fails :(
10501 		 *
10502 		 */
10503 		return (ENOMEM);
10504 	}
10505 	memset(tp->t_fb_ptr, 0, sizeof(struct tcp_rack));
10506 
10507 	rack = (struct tcp_rack *)tp->t_fb_ptr;
10508 	RB_INIT(&rack->r_ctl.rc_mtree);
10509 	TAILQ_INIT(&rack->r_ctl.rc_free);
10510 	TAILQ_INIT(&rack->r_ctl.rc_tmap);
10511 	rack->rc_tp = tp;
10512 	if (tp->t_inpcb) {
10513 		rack->rc_inp = tp->t_inpcb;
10514 	}
10515 	/* Probably not needed but lets be sure */
10516 	rack_clear_rate_sample(rack);
10517 	rack->r_ctl.rc_reorder_fade = rack_reorder_fade;
10518 	rack->rc_allow_data_af_clo = rack_ignore_data_after_close;
10519 	rack->r_ctl.rc_tlp_threshold = rack_tlp_thresh;
10520 	if (use_rack_rr)
10521 		rack->use_rack_rr = 1;
10522 	if (V_tcp_delack_enabled)
10523 		tp->t_delayed_ack = 1;
10524 	else
10525 		tp->t_delayed_ack = 0;
10526 	if (rack_enable_shared_cwnd)
10527 		rack->rack_enable_scwnd = 1;
10528 	rack->rc_user_set_max_segs = rack_hptsi_segments;
10529 	rack->rc_force_max_seg = 0;
10530 	if (rack_use_imac_dack)
10531 		rack->rc_dack_mode = 1;
10532 	rack->r_ctl.rc_reorder_shift = rack_reorder_thresh;
10533 	rack->r_ctl.rc_pkt_delay = rack_pkt_delay;
10534 	rack->r_ctl.rc_prop_reduce = rack_use_proportional_reduce;
10535 	rack->r_ctl.rc_prop_rate = rack_proportional_rate;
10536 	rack->r_ctl.rc_tlp_cwnd_reduce = rack_lower_cwnd_at_tlp;
10537 	rack->r_ctl.rc_early_recovery = rack_early_recovery;
10538 	rack->r_ctl.rc_lowest_us_rtt = 0xffffffff;
10539 	rack->r_ctl.rc_highest_us_rtt = 0;
10540 	if (rack_disable_prr)
10541 		rack->rack_no_prr = 1;
10542 	if (rack_gp_no_rec_chg)
10543 		rack->rc_gp_no_rec_chg = 1;
10544 	rack->rc_always_pace = rack_pace_every_seg;
10545 	if (rack_enable_mqueue_for_nonpaced)
10546 		rack->r_mbuf_queue = 1;
10547 	else
10548 		rack->r_mbuf_queue = 0;
10549 	if  (rack->r_mbuf_queue || rack->rc_always_pace)
10550 		tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
10551 	else
10552 		tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
10553 	rack_set_pace_segments(tp, rack, __LINE__);
10554 	if (rack_limits_scwnd)
10555 		rack->r_limit_scw  = 1;
10556 	else
10557 		rack->r_limit_scw  = 0;
10558 	rack->r_ctl.rc_high_rwnd = tp->snd_wnd;
10559 	rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
10560 	rack->r_ctl.rc_rate_sample_method = rack_rate_sample_method;
10561 	rack->rack_tlp_threshold_use = rack_tlp_threshold_use;
10562 	rack->r_ctl.rc_prr_sendalot = rack_send_a_lot_in_prr;
10563 	rack->r_ctl.rc_min_to = rack_min_to;
10564 	microuptime(&rack->r_ctl.act_rcv_time);
10565 	rack->r_ctl.rc_last_time_decay = rack->r_ctl.act_rcv_time;
10566 	rack->r_running_late = 0;
10567 	rack->r_running_early = 0;
10568 	rack->rc_init_win = rack_default_init_window;
10569 	rack->r_ctl.rack_per_of_gp_ss = rack_per_of_gp_ss;
10570 	if (rack_do_dyn_mul) {
10571 		/* When dynamic adjustment is on CA needs to start at 100% */
10572 		rack->rc_gp_dyn_mul = 1;
10573 		if (rack_do_dyn_mul >= 100)
10574 			rack->r_ctl.rack_per_of_gp_ca = rack_do_dyn_mul;
10575 	} else
10576 		rack->r_ctl.rack_per_of_gp_ca = rack_per_of_gp_ca;
10577 	rack->r_ctl.rack_per_of_gp_rec = rack_per_of_gp_rec;
10578 	rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
10579 	rack->r_ctl.rc_tlp_rxt_last_time = tcp_tv_to_mssectick(&rack->r_ctl.act_rcv_time);
10580 	setup_time_filter_small(&rack->r_ctl.rc_gp_min_rtt, FILTER_TYPE_MIN,
10581 				rack_probertt_filter_life);
10582 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
10583 	rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
10584 	rack->r_ctl.rc_time_of_last_probertt = us_cts;
10585 	rack->r_ctl.rc_time_probertt_starts = 0;
10586 	/* Do we force on detection? */
10587 #ifdef NETFLIX_EXP_DETECTION
10588 	if (tcp_force_detection)
10589 		rack->do_detection = 1;
10590 	else
10591 #endif
10592 		rack->do_detection = 0;
10593 	if (rack_non_rxt_use_cr)
10594 		rack->rack_rec_nonrxt_use_cr = 1;
10595 	if (tp->snd_una != tp->snd_max) {
10596 		/* Create a send map for the current outstanding data */
10597 		struct rack_sendmap *rsm;
10598 
10599 		rsm = rack_alloc(rack);
10600 		if (rsm == NULL) {
10601 			uma_zfree(rack_pcb_zone, tp->t_fb_ptr);
10602 			tp->t_fb_ptr = NULL;
10603 			return (ENOMEM);
10604 		}
10605 		rsm->r_flags = RACK_OVERMAX;
10606 		rsm->r_tim_lastsent[0] = rack->r_ctl.rc_tlp_rxt_last_time;
10607 		rsm->r_rtr_cnt = 1;
10608 		rsm->r_rtr_bytes = 0;
10609 		rsm->r_start = tp->snd_una;
10610 		rsm->r_end = tp->snd_max;
10611 		rsm->usec_orig_send = us_cts;
10612 		rsm->r_dupack = 0;
10613 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
10614 #ifdef INVARIANTS
10615 		if (insret != NULL) {
10616 			panic("Insert in rb tree fails ret:%p rack:%p rsm:%p",
10617 			      insret, rack, rsm);
10618 		}
10619 #endif
10620 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
10621 		rsm->r_in_tmap = 1;
10622 	}
10623 	/* Cancel the GP measurement in progress */
10624 	tp->t_flags &= ~TF_GPUTINPROG;
10625 	if (SEQ_GT(tp->snd_max, tp->iss))
10626 		snt = tp->snd_max - tp->iss;
10627 	else
10628 		snt = 0;
10629 	iwin = rc_init_window(rack);
10630 	if (snt < iwin) {
10631 		/* We are not past the initial window
10632 		 * so we need to make sure cwnd is
10633 		 * correct.
10634 		 */
10635 		if (tp->snd_cwnd < iwin)
10636 			tp->snd_cwnd = iwin;
10637 		/*
10638 		 * If we are within the initial window
10639 		 * we want ssthresh to be unlimited. Setting
10640 		 * it to the rwnd (which the default stack does
10641 		 * and older racks) is not really a good idea
10642 		 * since we want to be in SS and grow both the
10643 		 * cwnd and the rwnd (via dynamic rwnd growth). If
10644 		 * we set it to the rwnd then as the peer grows its
10645 		 * rwnd we will be stuck in CA and never hit SS.
10646 		 *
10647 		 * Its far better to raise it up high (this takes the
10648 		 * risk that there as been a loss already, probably
10649 		 * we should have an indicator in all stacks of loss
10650 		 * but we don't), but considering the normal use this
10651 		 * is a risk worth taking. The consequences of not
10652 		 * hitting SS are far worse than going one more time
10653 		 * into it early on (before we have sent even a IW).
10654 		 * It is highly unlikely that we will have had a loss
10655 		 * before getting the IW out.
10656 		 */
10657 		tp->snd_ssthresh = 0xffffffff;
10658 	}
10659 	rack_stop_all_timers(tp);
10660 	rack_start_hpts_timer(rack, tp, tcp_ts_getticks(), 0, 0, 0);
10661 	rack_log_rtt_shrinks(rack,  us_cts,  0,
10662 			     __LINE__, RACK_RTTS_INIT);
10663 	return (0);
10664 }
10665 
10666 static int
10667 rack_handoff_ok(struct tcpcb *tp)
10668 {
10669 	if ((tp->t_state == TCPS_CLOSED) ||
10670 	    (tp->t_state == TCPS_LISTEN)) {
10671 		/* Sure no problem though it may not stick */
10672 		return (0);
10673 	}
10674 	if ((tp->t_state == TCPS_SYN_SENT) ||
10675 	    (tp->t_state == TCPS_SYN_RECEIVED)) {
10676 		/*
10677 		 * We really don't know you have to get to ESTAB or beyond
10678 		 * to tell.
10679 		 */
10680 		return (EAGAIN);
10681 	}
10682 	if ((tp->t_flags & TF_SACK_PERMIT) || rack_sack_not_required){
10683 		return (0);
10684 	}
10685 	/*
10686 	 * If we reach here we don't do SACK on this connection so we can
10687 	 * never do rack.
10688 	 */
10689 	return (EINVAL);
10690 }
10691 
10692 static void
10693 rack_fini(struct tcpcb *tp, int32_t tcb_is_purged)
10694 {
10695 	if (tp->t_fb_ptr) {
10696 		struct tcp_rack *rack;
10697 		struct rack_sendmap *rsm, *nrsm, *rm;
10698 
10699 		rack = (struct tcp_rack *)tp->t_fb_ptr;
10700 #ifdef NETFLIX_SHARED_CWND
10701 		if (rack->r_ctl.rc_scw) {
10702 			uint32_t limit;
10703 
10704 			if (rack->r_limit_scw)
10705 				limit = max(1, rack->r_ctl.rc_lowest_us_rtt);
10706 			else
10707 				limit = 0;
10708 			tcp_shared_cwnd_free_full(tp, rack->r_ctl.rc_scw,
10709 						  rack->r_ctl.rc_scw_index,
10710 						  limit);
10711 			rack->r_ctl.rc_scw = NULL;
10712 		}
10713 #endif
10714 		/* rack does not use force data but other stacks may clear it */
10715 		tp->t_flags &= ~TF_FORCEDATA;
10716 		if (tp->t_inpcb) {
10717 			tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
10718 			tp->t_inpcb->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
10719 			tp->t_inpcb->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
10720 		}
10721 #ifdef TCP_BLACKBOX
10722 		tcp_log_flowend(tp);
10723 #endif
10724 		RB_FOREACH_SAFE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm) {
10725 			rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
10726 #ifdef INVARIANTS
10727 			if (rm != rsm) {
10728 				panic("At fini, rack:%p rsm:%p rm:%p",
10729 				      rack, rsm, rm);
10730 			}
10731 #endif
10732 			uma_zfree(rack_zone, rsm);
10733 		}
10734 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
10735 		while (rsm) {
10736 			TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
10737 			uma_zfree(rack_zone, rsm);
10738 			rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
10739 		}
10740 		rack->rc_free_cnt = 0;
10741 		uma_zfree(rack_pcb_zone, tp->t_fb_ptr);
10742 		tp->t_fb_ptr = NULL;
10743 	}
10744 	/* Cancel the GP measurement in progress */
10745 	tp->t_flags &= ~TF_GPUTINPROG;
10746 	/* Make sure snd_nxt is correctly set */
10747 	tp->snd_nxt = tp->snd_max;
10748 }
10749 
10750 
10751 static void
10752 rack_set_state(struct tcpcb *tp, struct tcp_rack *rack)
10753 {
10754 	switch (tp->t_state) {
10755 	case TCPS_SYN_SENT:
10756 		rack->r_state = TCPS_SYN_SENT;
10757 		rack->r_substate = rack_do_syn_sent;
10758 		break;
10759 	case TCPS_SYN_RECEIVED:
10760 		rack->r_state = TCPS_SYN_RECEIVED;
10761 		rack->r_substate = rack_do_syn_recv;
10762 		break;
10763 	case TCPS_ESTABLISHED:
10764 		rack_set_pace_segments(tp, rack, __LINE__);
10765 		rack->r_state = TCPS_ESTABLISHED;
10766 		rack->r_substate = rack_do_established;
10767 		break;
10768 	case TCPS_CLOSE_WAIT:
10769 		rack->r_state = TCPS_CLOSE_WAIT;
10770 		rack->r_substate = rack_do_close_wait;
10771 		break;
10772 	case TCPS_FIN_WAIT_1:
10773 		rack->r_state = TCPS_FIN_WAIT_1;
10774 		rack->r_substate = rack_do_fin_wait_1;
10775 		break;
10776 	case TCPS_CLOSING:
10777 		rack->r_state = TCPS_CLOSING;
10778 		rack->r_substate = rack_do_closing;
10779 		break;
10780 	case TCPS_LAST_ACK:
10781 		rack->r_state = TCPS_LAST_ACK;
10782 		rack->r_substate = rack_do_lastack;
10783 		break;
10784 	case TCPS_FIN_WAIT_2:
10785 		rack->r_state = TCPS_FIN_WAIT_2;
10786 		rack->r_substate = rack_do_fin_wait_2;
10787 		break;
10788 	case TCPS_LISTEN:
10789 	case TCPS_CLOSED:
10790 	case TCPS_TIME_WAIT:
10791 	default:
10792 		break;
10793 	};
10794 }
10795 
10796 
10797 static void
10798 rack_timer_audit(struct tcpcb *tp, struct tcp_rack *rack, struct sockbuf *sb)
10799 {
10800 	/*
10801 	 * We received an ack, and then did not
10802 	 * call send or were bounced out due to the
10803 	 * hpts was running. Now a timer is up as well, is
10804 	 * it the right timer?
10805 	 */
10806 	struct rack_sendmap *rsm;
10807 	int tmr_up;
10808 
10809 	tmr_up = rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
10810 	if (rack->rc_in_persist && (tmr_up == PACE_TMR_PERSIT))
10811 		return;
10812 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
10813 	if (((rsm == NULL) || (tp->t_state < TCPS_ESTABLISHED)) &&
10814 	    (tmr_up == PACE_TMR_RXT)) {
10815 		/* Should be an RXT */
10816 		return;
10817 	}
10818 	if (rsm == NULL) {
10819 		/* Nothing outstanding? */
10820 		if (tp->t_flags & TF_DELACK) {
10821 			if (tmr_up == PACE_TMR_DELACK)
10822 				/* We are supposed to have delayed ack up and we do */
10823 				return;
10824 		} else if (sbavail(&tp->t_inpcb->inp_socket->so_snd) && (tmr_up == PACE_TMR_RXT)) {
10825 			/*
10826 			 * if we hit enobufs then we would expect the possiblity
10827 			 * of nothing outstanding and the RXT up (and the hptsi timer).
10828 			 */
10829 			return;
10830 		} else if (((V_tcp_always_keepalive ||
10831 			     rack->rc_inp->inp_socket->so_options & SO_KEEPALIVE) &&
10832 			    (tp->t_state <= TCPS_CLOSING)) &&
10833 			   (tmr_up == PACE_TMR_KEEP) &&
10834 			   (tp->snd_max == tp->snd_una)) {
10835 			/* We should have keep alive up and we do */
10836 			return;
10837 		}
10838 	}
10839 	if (SEQ_GT(tp->snd_max, tp->snd_una) &&
10840 		   ((tmr_up == PACE_TMR_TLP) ||
10841 		    (tmr_up == PACE_TMR_RACK) ||
10842 		    (tmr_up == PACE_TMR_RXT))) {
10843 		/*
10844 		 * Either a Rack, TLP or RXT is fine if  we
10845 		 * have outstanding data.
10846 		 */
10847 		return;
10848 	} else if (tmr_up == PACE_TMR_DELACK) {
10849 		/*
10850 		 * If the delayed ack was going to go off
10851 		 * before the rtx/tlp/rack timer were going to
10852 		 * expire, then that would be the timer in control.
10853 		 * Note we don't check the time here trusting the
10854 		 * code is correct.
10855 		 */
10856 		return;
10857 	}
10858 	/*
10859 	 * Ok the timer originally started is not what we want now.
10860 	 * We will force the hpts to be stopped if any, and restart
10861 	 * with the slot set to what was in the saved slot.
10862 	 */
10863 	if (rack->rc_inp->inp_in_hpts) {
10864 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
10865 			uint32_t us_cts;
10866 
10867 			us_cts = tcp_get_usecs(NULL);
10868 			if (TSTMP_GT(rack->r_ctl.rc_last_output_to, us_cts)) {
10869 				rack->r_early = 1;
10870 				rack->r_ctl.rc_agg_early += (rack->r_ctl.rc_last_output_to - us_cts);
10871 			}
10872 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
10873 		}
10874 		tcp_hpts_remove(tp->t_inpcb, HPTS_REMOVE_OUTPUT);
10875 	}
10876 	rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
10877 	rack_start_hpts_timer(rack, tp, tcp_ts_getticks(), 0, 0, 0);
10878 }
10879 
10880 static int
10881 rack_do_segment_nounlock(struct mbuf *m, struct tcphdr *th, struct socket *so,
10882     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos,
10883     int32_t nxt_pkt, struct timeval *tv)
10884 {
10885 	int32_t thflags, retval, did_out = 0;
10886 	int32_t way_out = 0;
10887 	uint32_t cts;
10888 	uint32_t tiwin;
10889 	struct timespec ts;
10890 	struct tcpopt to;
10891 	struct tcp_rack *rack;
10892 	struct rack_sendmap *rsm;
10893 	int32_t prev_state = 0;
10894 	uint32_t us_cts;
10895 	/*
10896 	 * tv passed from common code is from either M_TSTMP_LRO or
10897 	 * tcp_get_usecs() if no LRO m_pkthdr timestamp is present. The
10898 	 * rack_pacing stack assumes tv always refers to 'now', so we overwrite
10899 	 * tv here to guarantee that.
10900 	 */
10901 	if (m->m_flags & M_TSTMP_LRO)
10902 		tcp_get_usecs(tv);
10903 
10904 	cts = tcp_tv_to_mssectick(tv);
10905 	rack = (struct tcp_rack *)tp->t_fb_ptr;
10906 
10907 	if ((m->m_flags & M_TSTMP) ||
10908 	    (m->m_flags & M_TSTMP_LRO)) {
10909 		mbuf_tstmp2timespec(m, &ts);
10910 		rack->r_ctl.act_rcv_time.tv_sec = ts.tv_sec;
10911 		rack->r_ctl.act_rcv_time.tv_usec = ts.tv_nsec/1000;
10912 	} else
10913 		rack->r_ctl.act_rcv_time = *tv;
10914 	kern_prefetch(rack, &prev_state);
10915 	prev_state = 0;
10916 	thflags = th->th_flags;
10917 
10918 	NET_EPOCH_ASSERT();
10919 	INP_WLOCK_ASSERT(tp->t_inpcb);
10920 	KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN",
10921 	    __func__));
10922 	KASSERT(tp->t_state != TCPS_TIME_WAIT, ("%s: TCPS_TIME_WAIT",
10923 	    __func__));
10924 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
10925 		union tcp_log_stackspecific log;
10926 		struct timeval ltv;
10927 #ifdef NETFLIX_HTTP_LOGGING
10928 		struct http_sendfile_track *http_req;
10929 
10930 		if (SEQ_GT(th->th_ack, tp->snd_una)) {
10931 			http_req = tcp_http_find_req_for_seq(tp, (th->th_ack-1));
10932 		} else {
10933 			http_req = tcp_http_find_req_for_seq(tp, th->th_ack);
10934 		}
10935 #endif
10936 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
10937 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
10938 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
10939 		if (rack->rack_no_prr == 0)
10940 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
10941 		else
10942 			log.u_bbr.flex1 = 0;
10943 		log.u_bbr.flex2 = rack->r_ctl.rc_num_maps_alloced;
10944 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
10945 		log.u_bbr.pkts_out = rack->rc_tp->t_maxseg;
10946 		log.u_bbr.flex3 = m->m_flags;
10947 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
10948 		if (m->m_flags & M_TSTMP) {
10949 			/* Record the hardware timestamp if present */
10950 			mbuf_tstmp2timespec(m, &ts);
10951 			ltv.tv_sec = ts.tv_sec;
10952 			ltv.tv_usec = ts.tv_nsec / 1000;
10953 			log.u_bbr.lt_epoch = tcp_tv_to_usectick(&ltv);
10954 		} else if (m->m_flags & M_TSTMP_LRO) {
10955 			/* Record the LRO the arrival timestamp */
10956 			mbuf_tstmp2timespec(m, &ts);
10957 			ltv.tv_sec = ts.tv_sec;
10958 			ltv.tv_usec = ts.tv_nsec / 1000;
10959 			log.u_bbr.flex5 = tcp_tv_to_usectick(&ltv);
10960 		}
10961 		log.u_bbr.timeStamp = tcp_get_usecs(&ltv);
10962 		/* Log the rcv time */
10963 		log.u_bbr.delRate = m->m_pkthdr.rcv_tstmp;
10964 #ifdef NETFLIX_HTTP_LOGGING
10965 		log.u_bbr.applimited = tp->t_http_closed;
10966 		log.u_bbr.applimited <<= 8;
10967 		log.u_bbr.applimited |= tp->t_http_open;
10968 		log.u_bbr.applimited <<= 8;
10969 		log.u_bbr.applimited |= tp->t_http_req;
10970 		if (http_req) {
10971 			/* Copy out any client req info */
10972 			/* seconds */
10973 			log.u_bbr.pkt_epoch = (http_req->localtime / HPTS_USEC_IN_SEC);
10974 			/* useconds */
10975 			log.u_bbr.delivered = (http_req->localtime % HPTS_USEC_IN_SEC);
10976 			log.u_bbr.rttProp = http_req->timestamp;
10977 			log.u_bbr.cur_del_rate = http_req->start;
10978 			if (http_req->flags & TCP_HTTP_TRACK_FLG_OPEN) {
10979 				log.u_bbr.flex8 |= 1;
10980 			} else {
10981 				log.u_bbr.flex8 |= 2;
10982 				log.u_bbr.bw_inuse = http_req->end;
10983 			}
10984 			log.u_bbr.flex6 = http_req->start_seq;
10985 			if (http_req->flags & TCP_HTTP_TRACK_FLG_COMP) {
10986 				log.u_bbr.flex8 |= 4;
10987 				log.u_bbr.epoch = http_req->end_seq;
10988 			}
10989 		}
10990 #endif
10991 		TCP_LOG_EVENTP(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_IN, 0,
10992 		    tlen, &log, true, &ltv);
10993 	}
10994 	if ((thflags & TH_SYN) && (thflags & TH_FIN) && V_drop_synfin) {
10995 		way_out = 4;
10996 		retval = 0;
10997 		goto done_with_input;
10998 	}
10999 	/*
11000 	 * If a segment with the ACK-bit set arrives in the SYN-SENT state
11001 	 * check SEQ.ACK first as described on page 66 of RFC 793, section 3.9.
11002 	 */
11003 	if ((tp->t_state == TCPS_SYN_SENT) && (thflags & TH_ACK) &&
11004 	    (SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) {
11005 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
11006 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11007 		return(1);
11008 	}
11009 	/*
11010 	 * Segment received on connection. Reset idle time and keep-alive
11011 	 * timer. XXX: This should be done after segment validation to
11012 	 * ignore broken/spoofed segs.
11013 	 */
11014 	if  (tp->t_idle_reduce &&
11015 	     (tp->snd_max == tp->snd_una) &&
11016 	     ((ticks - tp->t_rcvtime) >= tp->t_rxtcur)) {
11017 		counter_u64_add(rack_input_idle_reduces, 1);
11018 		rack_cc_after_idle(rack, tp);
11019 	}
11020 	tp->t_rcvtime = ticks;
11021 	/*
11022 	 * Unscale the window into a 32-bit value. For the SYN_SENT state
11023 	 * the scale is zero.
11024 	 */
11025 	tiwin = th->th_win << tp->snd_scale;
11026 #ifdef STATS
11027 	stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_FRWIN, tiwin);
11028 #endif
11029 	if (tiwin > rack->r_ctl.rc_high_rwnd)
11030 		rack->r_ctl.rc_high_rwnd = tiwin;
11031 	/*
11032 	 * TCP ECN processing. XXXJTL: If we ever use ECN, we need to move
11033 	 * this to occur after we've validated the segment.
11034 	 */
11035 	if (tp->t_flags2 & TF2_ECN_PERMIT) {
11036 		if (thflags & TH_CWR) {
11037 			tp->t_flags2 &= ~TF2_ECN_SND_ECE;
11038 			tp->t_flags |= TF_ACKNOW;
11039 		}
11040 		switch (iptos & IPTOS_ECN_MASK) {
11041 		case IPTOS_ECN_CE:
11042 			tp->t_flags2 |= TF2_ECN_SND_ECE;
11043 			KMOD_TCPSTAT_INC(tcps_ecn_ce);
11044 			break;
11045 		case IPTOS_ECN_ECT0:
11046 			KMOD_TCPSTAT_INC(tcps_ecn_ect0);
11047 			break;
11048 		case IPTOS_ECN_ECT1:
11049 			KMOD_TCPSTAT_INC(tcps_ecn_ect1);
11050 			break;
11051 		}
11052 
11053 		/* Process a packet differently from RFC3168. */
11054 		cc_ecnpkt_handler(tp, th, iptos);
11055 
11056 		/* Congestion experienced. */
11057 		if (thflags & TH_ECE) {
11058 			rack_cong_signal(tp, th, CC_ECN);
11059 		}
11060 	}
11061 	/*
11062 	 * Parse options on any incoming segment.
11063 	 */
11064 	tcp_dooptions(&to, (u_char *)(th + 1),
11065 	    (th->th_off << 2) - sizeof(struct tcphdr),
11066 	    (thflags & TH_SYN) ? TO_SYN : 0);
11067 
11068 	/*
11069 	 * If echoed timestamp is later than the current time, fall back to
11070 	 * non RFC1323 RTT calculation.  Normalize timestamp if syncookies
11071 	 * were used when this connection was established.
11072 	 */
11073 	if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) {
11074 		to.to_tsecr -= tp->ts_offset;
11075 		if (TSTMP_GT(to.to_tsecr, cts))
11076 			to.to_tsecr = 0;
11077 	}
11078 
11079 	/*
11080 	 * If its the first time in we need to take care of options and
11081 	 * verify we can do SACK for rack!
11082 	 */
11083 	if (rack->r_state == 0) {
11084 		/* Should be init'd by rack_init() */
11085 		KASSERT(rack->rc_inp != NULL,
11086 		    ("%s: rack->rc_inp unexpectedly NULL", __func__));
11087 		if (rack->rc_inp == NULL) {
11088 			rack->rc_inp = tp->t_inpcb;
11089 		}
11090 
11091 		/*
11092 		 * Process options only when we get SYN/ACK back. The SYN
11093 		 * case for incoming connections is handled in tcp_syncache.
11094 		 * According to RFC1323 the window field in a SYN (i.e., a
11095 		 * <SYN> or <SYN,ACK>) segment itself is never scaled. XXX
11096 		 * this is traditional behavior, may need to be cleaned up.
11097 		 */
11098 		if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
11099 			/* Handle parallel SYN for ECN */
11100 			if (!(thflags & TH_ACK) &&
11101 			    ((thflags & (TH_CWR | TH_ECE)) == (TH_CWR | TH_ECE)) &&
11102 			    ((V_tcp_do_ecn == 1) || (V_tcp_do_ecn == 2))) {
11103 				tp->t_flags2 |= TF2_ECN_PERMIT;
11104 				tp->t_flags2 |= TF2_ECN_SND_ECE;
11105 				TCPSTAT_INC(tcps_ecn_shs);
11106 			}
11107 			if ((to.to_flags & TOF_SCALE) &&
11108 			    (tp->t_flags & TF_REQ_SCALE)) {
11109 				tp->t_flags |= TF_RCVD_SCALE;
11110 				tp->snd_scale = to.to_wscale;
11111 			} else
11112 				tp->t_flags &= ~TF_REQ_SCALE;
11113 			/*
11114 			 * Initial send window.  It will be updated with the
11115 			 * next incoming segment to the scaled value.
11116 			 */
11117 			tp->snd_wnd = th->th_win;
11118 			if ((to.to_flags & TOF_TS) &&
11119 			    (tp->t_flags & TF_REQ_TSTMP)) {
11120 				tp->t_flags |= TF_RCVD_TSTMP;
11121 				tp->ts_recent = to.to_tsval;
11122 				tp->ts_recent_age = cts;
11123 			} else
11124 				tp->t_flags &= ~TF_REQ_TSTMP;
11125 			if (to.to_flags & TOF_MSS)
11126 				tcp_mss(tp, to.to_mss);
11127 			if ((tp->t_flags & TF_SACK_PERMIT) &&
11128 			    (to.to_flags & TOF_SACKPERM) == 0)
11129 				tp->t_flags &= ~TF_SACK_PERMIT;
11130 			if (IS_FASTOPEN(tp->t_flags)) {
11131 				if (to.to_flags & TOF_FASTOPEN) {
11132 					uint16_t mss;
11133 
11134 					if (to.to_flags & TOF_MSS)
11135 						mss = to.to_mss;
11136 					else
11137 						if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
11138 							mss = TCP6_MSS;
11139 						else
11140 							mss = TCP_MSS;
11141 					tcp_fastopen_update_cache(tp, mss,
11142 					    to.to_tfo_len, to.to_tfo_cookie);
11143 				} else
11144 					tcp_fastopen_disable_path(tp);
11145 			}
11146 		}
11147 		/*
11148 		 * At this point we are at the initial call. Here we decide
11149 		 * if we are doing RACK or not. We do this by seeing if
11150 		 * TF_SACK_PERMIT is set and the sack-not-required is clear.
11151 		 * The code now does do dup-ack counting so if you don't
11152 		 * switch back you won't get rack & TLP, but you will still
11153 		 * get this stack.
11154 		 */
11155 
11156 		if ((rack_sack_not_required == 0) &&
11157 		    ((tp->t_flags & TF_SACK_PERMIT) == 0)) {
11158 			tcp_switch_back_to_default(tp);
11159 			(*tp->t_fb->tfb_tcp_do_segment) (m, th, so, tp, drop_hdrlen,
11160 			    tlen, iptos);
11161 			return (1);
11162 		}
11163 		/* Set the flag */
11164 		rack->r_is_v6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0;
11165 		tcp_set_hpts(tp->t_inpcb);
11166 		sack_filter_clear(&rack->r_ctl.rack_sf, th->th_ack);
11167 	}
11168 	if (thflags & TH_FIN)
11169 		tcp_log_end_status(tp, TCP_EI_STATUS_CLIENT_FIN);
11170 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
11171 	if ((rack->rc_gp_dyn_mul) &&
11172 	    (rack->use_fixed_rate == 0) &&
11173 	    (rack->rc_always_pace)) {
11174 		/* Check in on probertt */
11175 		rack_check_probe_rtt(rack, us_cts);
11176 	}
11177 	if (rack->forced_ack) {
11178 		uint32_t us_rtt;
11179 
11180 		/*
11181 		 * A persist or keep-alive was forced out, update our
11182 		 * min rtt time. Note we do not worry about lost
11183 		 * retransmissions since KEEP-ALIVES and persists
11184 		 * are usually way long on times of sending (though
11185 		 * if we were really paranoid or worried we could
11186 		 * at least use timestamps if available to validate).
11187 		 */
11188 		rack->forced_ack = 0;
11189 		us_rtt = us_cts - rack->r_ctl.forced_ack_ts;
11190 		if (us_rtt == 0)
11191 			us_rtt = 1;
11192 		rack_log_rtt_upd(tp, rack, us_rtt, 0, NULL, 3);
11193 		rack_apply_updated_usrtt(rack, us_rtt, us_cts);
11194 	}
11195 	/*
11196 	 * This is the one exception case where we set the rack state
11197 	 * always. All other times (timers etc) we must have a rack-state
11198 	 * set (so we assure we have done the checks above for SACK).
11199 	 */
11200 	rack->r_ctl.rc_rcvtime = cts;
11201 	if (rack->r_state != tp->t_state)
11202 		rack_set_state(tp, rack);
11203 	if (SEQ_GT(th->th_ack, tp->snd_una) &&
11204 	    (rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree)) != NULL)
11205 		kern_prefetch(rsm, &prev_state);
11206 	prev_state = rack->r_state;
11207 	rack_clear_rate_sample(rack);
11208 	retval = (*rack->r_substate) (m, th, so,
11209 	    tp, &to, drop_hdrlen,
11210 	    tlen, tiwin, thflags, nxt_pkt, iptos);
11211 #ifdef INVARIANTS
11212 	if ((retval == 0) &&
11213 	    (tp->t_inpcb == NULL)) {
11214 		panic("retval:%d tp:%p t_inpcb:NULL state:%d",
11215 		    retval, tp, prev_state);
11216 	}
11217 #endif
11218 	if (retval == 0) {
11219 		/*
11220 		 * If retval is 1 the tcb is unlocked and most likely the tp
11221 		 * is gone.
11222 		 */
11223 		INP_WLOCK_ASSERT(tp->t_inpcb);
11224 		if ((rack->rc_gp_dyn_mul) &&
11225 		    (rack->rc_always_pace) &&
11226 		    (rack->use_fixed_rate == 0) &&
11227 		    rack->in_probe_rtt &&
11228 		    (rack->r_ctl.rc_time_probertt_starts == 0)) {
11229 			/*
11230 			 * If we are going for target, lets recheck before
11231 			 * we output.
11232 			 */
11233 			rack_check_probe_rtt(rack, us_cts);
11234 		}
11235 		if (rack->set_pacing_done_a_iw == 0) {
11236 			/* How much has been acked? */
11237 			if ((tp->snd_una - tp->iss) > (ctf_fixed_maxseg(tp) * 10)) {
11238 				/* We have enough to set in the pacing segment size */
11239 				rack->set_pacing_done_a_iw = 1;
11240 				rack_set_pace_segments(tp, rack, __LINE__);
11241 			}
11242 		}
11243 		tcp_rack_xmit_timer_commit(rack, tp);
11244 		if (nxt_pkt == 0) {
11245 			if (rack->r_wanted_output != 0) {
11246 do_output_now:
11247 				did_out = 1;
11248 				(void)tp->t_fb->tfb_tcp_output(tp);
11249 			}
11250 			rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
11251 		}
11252 		if ((nxt_pkt == 0) &&
11253 		    ((rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) == 0) &&
11254 		    (SEQ_GT(tp->snd_max, tp->snd_una) ||
11255 		     (tp->t_flags & TF_DELACK) ||
11256 		     ((V_tcp_always_keepalive || rack->rc_inp->inp_socket->so_options & SO_KEEPALIVE) &&
11257 		      (tp->t_state <= TCPS_CLOSING)))) {
11258 			/* We could not send (probably in the hpts but stopped the timer earlier)? */
11259 			if ((tp->snd_max == tp->snd_una) &&
11260 			    ((tp->t_flags & TF_DELACK) == 0) &&
11261 			    (rack->rc_inp->inp_in_hpts) &&
11262 			    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
11263 				/* keep alive not needed if we are hptsi output yet */
11264 				;
11265 			} else {
11266 				int late = 0;
11267 				if (rack->rc_inp->inp_in_hpts) {
11268 					if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
11269 						us_cts = tcp_get_usecs(NULL);
11270 						if (TSTMP_GT(rack->r_ctl.rc_last_output_to, us_cts)) {
11271 							rack->r_early = 1;
11272 							rack->r_ctl.rc_agg_early += (rack->r_ctl.rc_last_output_to - us_cts);
11273 						} else
11274 							late = 1;
11275 						rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
11276 					}
11277 					tcp_hpts_remove(tp->t_inpcb, HPTS_REMOVE_OUTPUT);
11278 				}
11279 				if (late && (did_out == 0)) {
11280 					/*
11281 					 * We are late in the sending
11282 					 * and we did not call the output
11283 					 * (this probably should not happen).
11284 					 */
11285 					goto do_output_now;
11286 				}
11287 				rack_start_hpts_timer(rack, tp, tcp_ts_getticks(), 0, 0, 0);
11288 			}
11289 			way_out = 1;
11290 		} else if (nxt_pkt == 0) {
11291 			/* Do we have the correct timer running? */
11292 			rack_timer_audit(tp, rack, &so->so_snd);
11293 			way_out = 2;
11294 		}
11295 	done_with_input:
11296 		rack_log_doseg_done(rack, cts, nxt_pkt, did_out, way_out);
11297 		if (did_out)
11298 			rack->r_wanted_output = 0;
11299 #ifdef INVARIANTS
11300 		if (tp->t_inpcb == NULL) {
11301 			panic("OP:%d retval:%d tp:%p t_inpcb:NULL state:%d",
11302 			      did_out,
11303 			      retval, tp, prev_state);
11304 		}
11305 #endif
11306 	}
11307 	return (retval);
11308 }
11309 
11310 void
11311 rack_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
11312     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos)
11313 {
11314 	struct timeval tv;
11315 
11316 	/* First lets see if we have old packets */
11317 	if (tp->t_in_pkt) {
11318 		if (ctf_do_queued_segments(so, tp, 1)) {
11319 			m_freem(m);
11320 			return;
11321 		}
11322 	}
11323 	if (m->m_flags & M_TSTMP_LRO) {
11324 		tv.tv_sec = m->m_pkthdr.rcv_tstmp /1000000000;
11325 		tv.tv_usec = (m->m_pkthdr.rcv_tstmp % 1000000000)/1000;
11326 	} else {
11327 		/* Should not be should we kassert instead? */
11328 		tcp_get_usecs(&tv);
11329 	}
11330 	if(rack_do_segment_nounlock(m, th, so, tp,
11331 				    drop_hdrlen, tlen, iptos, 0, &tv) == 0)
11332 		INP_WUNLOCK(tp->t_inpcb);
11333 }
11334 
11335 struct rack_sendmap *
11336 tcp_rack_output(struct tcpcb *tp, struct tcp_rack *rack, uint32_t tsused)
11337 {
11338 	struct rack_sendmap *rsm = NULL;
11339 	int32_t idx;
11340 	uint32_t srtt = 0, thresh = 0, ts_low = 0;
11341 
11342 	/* Return the next guy to be re-transmitted */
11343 	if (RB_EMPTY(&rack->r_ctl.rc_mtree)) {
11344 		return (NULL);
11345 	}
11346 	if (tp->t_flags & TF_SENTFIN) {
11347 		/* retran the end FIN? */
11348 		return (NULL);
11349 	}
11350 	/* ok lets look at this one */
11351 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
11352 	if (rsm && ((rsm->r_flags & RACK_ACKED) == 0)) {
11353 		goto check_it;
11354 	}
11355 	rsm = rack_find_lowest_rsm(rack);
11356 	if (rsm == NULL) {
11357 		return (NULL);
11358 	}
11359 check_it:
11360 	if (rsm->r_flags & RACK_ACKED) {
11361 		return (NULL);
11362 	}
11363 	if (((rsm->r_flags & RACK_SACK_PASSED) == 0) &&
11364 	    (rsm->r_dupack < DUP_ACK_THRESHOLD)) {
11365 		/* Its not yet ready */
11366 		return (NULL);
11367 	}
11368 	srtt = rack_grab_rtt(tp, rack);
11369 	idx = rsm->r_rtr_cnt - 1;
11370 	ts_low = rsm->r_tim_lastsent[idx];
11371 	thresh = rack_calc_thresh_rack(rack, srtt, tsused);
11372 	if ((tsused == ts_low) ||
11373 	    (TSTMP_LT(tsused, ts_low))) {
11374 		/* No time since sending */
11375 		return (NULL);
11376 	}
11377 	if ((tsused - ts_low) < thresh) {
11378 		/* It has not been long enough yet */
11379 		return (NULL);
11380 	}
11381 	if ((rsm->r_dupack >= DUP_ACK_THRESHOLD) ||
11382 	    ((rsm->r_flags & RACK_SACK_PASSED) &&
11383 	     (rack->sack_attack_disable == 0))) {
11384 		/*
11385 		 * We have passed the dup-ack threshold <or>
11386 		 * a SACK has indicated this is missing.
11387 		 * Note that if you are a declared attacker
11388 		 * it is only the dup-ack threshold that
11389 		 * will cause retransmits.
11390 		 */
11391 		/* log retransmit reason */
11392 		rack_log_retran_reason(rack, rsm, (tsused - ts_low), thresh, 1);
11393 		return (rsm);
11394 	}
11395 	return (NULL);
11396 }
11397 
11398 static void
11399 rack_log_pacing_delay_calc(struct tcp_rack *rack, uint32_t len, uint32_t slot,
11400 			   uint64_t bw_est, uint64_t bw, uint64_t len_time, int method,
11401 			   int line, struct rack_sendmap *rsm)
11402 {
11403 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
11404 		union tcp_log_stackspecific log;
11405 		struct timeval tv;
11406 
11407 		memset(&log, 0, sizeof(log));
11408 		log.u_bbr.flex1 = slot;
11409 		log.u_bbr.flex2 = len;
11410 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_min_segs;
11411 		log.u_bbr.flex4 = rack->r_ctl.rc_pace_max_segs;
11412 		log.u_bbr.flex5 = rack->r_ctl.rack_per_of_gp_ss;
11413 		log.u_bbr.flex6 = rack->r_ctl.rack_per_of_gp_ca;
11414 		log.u_bbr.use_lt_bw = rack->app_limited_needs_set;
11415 		log.u_bbr.use_lt_bw <<= 1;
11416 		log.u_bbr.use_lt_bw = rack->rc_gp_filled;
11417 		log.u_bbr.use_lt_bw <<= 1;
11418 		log.u_bbr.use_lt_bw |= rack->measure_saw_probe_rtt;
11419 		log.u_bbr.use_lt_bw <<= 1;
11420 		log.u_bbr.use_lt_bw |= rack->in_probe_rtt;
11421 		log.u_bbr.pkt_epoch = line;
11422 		log.u_bbr.applimited = rack->r_ctl.rack_per_of_gp_rec;
11423 		log.u_bbr.bw_inuse = bw_est;
11424 		log.u_bbr.delRate = bw;
11425 		if (rack->r_ctl.gp_bw == 0)
11426 			log.u_bbr.cur_del_rate = 0;
11427 		else
11428 			log.u_bbr.cur_del_rate = rack_get_bw(rack);
11429 		log.u_bbr.rttProp = len_time;
11430 		log.u_bbr.pkts_out = rack->r_ctl.rc_rack_min_rtt;
11431 		log.u_bbr.lost = rack->r_ctl.rc_probertt_sndmax_atexit;
11432 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, rsm);
11433 		if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh) {
11434 			/* We are in slow start */
11435 			log.u_bbr.flex7 = 1;
11436 		} else {
11437 			/* we are on congestion avoidance */
11438 			log.u_bbr.flex7 = 0;
11439 		}
11440 		log.u_bbr.flex8 = method;
11441 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
11442 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
11443 		log.u_bbr.cwnd_gain = rack->rc_gp_saw_rec;
11444 		log.u_bbr.cwnd_gain <<= 1;
11445 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ss;
11446 		log.u_bbr.cwnd_gain <<= 1;
11447 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ca;
11448 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
11449 		    &rack->rc_inp->inp_socket->so_rcv,
11450 		    &rack->rc_inp->inp_socket->so_snd,
11451 		    BBR_LOG_HPTSI_CALC, 0,
11452 		    0, &log, false, &tv);
11453 	}
11454 }
11455 
11456 static uint32_t
11457 rack_get_pacing_len(struct tcp_rack *rack, uint64_t bw, uint32_t mss)
11458 {
11459 	uint32_t new_tso, user_max;
11460 
11461 	user_max = rack->rc_user_set_max_segs * mss;
11462 	if (rack->rc_force_max_seg) {
11463 		return (user_max);
11464 	}
11465 	if (rack->use_fixed_rate &&
11466 	    ((rack->r_ctl.crte == NULL) ||
11467 	     (bw != rack->r_ctl.crte->rate))) {
11468 		/* Use the user mss since we are not exactly matched */
11469 		return (user_max);
11470 	}
11471 	new_tso = tcp_get_pacing_burst_size(bw, mss, rack_pace_one_seg, rack->r_ctl.crte, NULL);
11472 	if (new_tso > user_max)
11473 		new_tso = user_max;
11474 	return(new_tso);
11475 }
11476 
11477 static void
11478 rack_log_hdwr_pacing(struct tcp_rack *rack, const struct ifnet *ifp,
11479 		     uint64_t rate, uint64_t hw_rate, int line,
11480 		     int error)
11481 {
11482 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
11483 		union tcp_log_stackspecific log;
11484 		struct timeval tv;
11485 
11486 		memset(&log, 0, sizeof(log));
11487 		log.u_bbr.flex1 = ((hw_rate >> 32) & 0x00000000ffffffff);
11488 		log.u_bbr.flex2 = (hw_rate & 0x00000000ffffffff);
11489 		log.u_bbr.flex3 = (((uint64_t)ifp  >> 32) & 0x00000000ffffffff);
11490 		log.u_bbr.flex4 = ((uint64_t)ifp & 0x00000000ffffffff);
11491 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
11492 		log.u_bbr.bw_inuse = rate;
11493 		log.u_bbr.flex5 = line;
11494 		log.u_bbr.flex6 = error;
11495 		log.u_bbr.applimited = rack->r_ctl.rc_pace_max_segs;
11496 		log.u_bbr.flex8 = rack->use_fixed_rate;
11497 		log.u_bbr.flex8 <<= 1;
11498 		log.u_bbr.flex8 |= rack->rack_hdrw_pacing;
11499 		log.u_bbr.pkts_out = rack->rc_tp->t_maxseg;
11500 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
11501 		    &rack->rc_inp->inp_socket->so_rcv,
11502 		    &rack->rc_inp->inp_socket->so_snd,
11503 		    BBR_LOG_HDWR_PACE, 0,
11504 		    0, &log, false, &tv);
11505 	}
11506 }
11507 
11508 static int32_t
11509 pace_to_fill_cwnd(struct tcp_rack *rack, int32_t slot, uint32_t len, uint32_t segsiz)
11510 {
11511 	uint64_t lentim, fill_bw;
11512 
11513 	/* Lets first see if we are full, if so continue with normal rate */
11514 	if (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) > rack->r_ctl.cwnd_to_use)
11515 		return (slot);
11516 	if ((ctf_outstanding(rack->rc_tp) + (segsiz-1)) > rack->rc_tp->snd_wnd)
11517 		return (slot);
11518 	if (rack->r_ctl.rc_last_us_rtt == 0)
11519 		return (slot);
11520 	if (rack->rc_pace_fill_if_rttin_range &&
11521 	    (rack->r_ctl.rc_last_us_rtt >=
11522 	     (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack->rtt_limit_mul))) {
11523 		/* The rtt is huge, N * smallest, lets not fill */
11524 		return (slot);
11525 	}
11526 	/*
11527 	 * first lets calculate the b/w based on the last us-rtt
11528 	 * and the sndwnd.
11529 	 */
11530 	fill_bw = rack->r_ctl.cwnd_to_use;
11531 	/* Take the rwnd if its smaller */
11532 	if (fill_bw > rack->rc_tp->snd_wnd)
11533 		fill_bw = rack->rc_tp->snd_wnd;
11534 	fill_bw *= (uint64_t)HPTS_USEC_IN_SEC;
11535 	fill_bw /= (uint64_t)rack->r_ctl.rc_last_us_rtt;
11536 	/* We are below the min b/w */
11537 	if (fill_bw < RACK_MIN_BW)
11538 		return (slot);
11539 	/*
11540 	 * Ok fill_bw holds our mythical b/w to fill the cwnd
11541 	 * in a rtt, what does that time wise equate too?
11542 	 */
11543 	lentim = (uint64_t)(len) * (uint64_t)HPTS_USEC_IN_SEC;
11544 	lentim /= fill_bw;
11545 	if (lentim < slot) {
11546 		rack_log_pacing_delay_calc(rack, len, slot, fill_bw,
11547 					   0, lentim, 12, __LINE__, NULL);
11548 		return ((int32_t)lentim);
11549 	} else
11550 		return (slot);
11551 }
11552 
11553 static int32_t
11554 rack_get_pacing_delay(struct tcp_rack *rack, struct tcpcb *tp, uint32_t len, struct rack_sendmap *rsm, uint32_t segsiz)
11555 {
11556 	struct rack_sendmap *lrsm;
11557 	int32_t slot = 0;
11558 	int err;
11559 
11560 	if (rack->rc_always_pace == 0) {
11561 		/*
11562 		 * We use the most optimistic possible cwnd/srtt for
11563 		 * sending calculations. This will make our
11564 		 * calculation anticipate getting more through
11565 		 * quicker then possible. But thats ok we don't want
11566 		 * the peer to have a gap in data sending.
11567 		 */
11568 		uint32_t srtt, cwnd, tr_perms = 0;
11569 		int32_t reduce = 0;
11570 
11571 	old_method:
11572 		/*
11573 		 * We keep no precise pacing with the old method
11574 		 * instead we use the pacer to mitigate bursts.
11575 		 */
11576 		rack->r_ctl.rc_agg_delayed = 0;
11577 		rack->r_early = 0;
11578 		rack->r_late = 0;
11579 		rack->r_ctl.rc_agg_early = 0;
11580 		if (rack->r_ctl.rc_rack_min_rtt)
11581 			srtt = rack->r_ctl.rc_rack_min_rtt;
11582 		else
11583 			srtt = TICKS_2_MSEC((tp->t_srtt >> TCP_RTT_SHIFT));
11584 		if (rack->r_ctl.rc_rack_largest_cwnd)
11585 			cwnd = rack->r_ctl.rc_rack_largest_cwnd;
11586 		else
11587 			cwnd = rack->r_ctl.cwnd_to_use;
11588 		tr_perms = cwnd / srtt;
11589 		if (tr_perms == 0) {
11590 			tr_perms = ctf_fixed_maxseg(tp);
11591 		}
11592 		/*
11593 		 * Calculate how long this will take to drain, if
11594 		 * the calculation comes out to zero, thats ok we
11595 		 * will use send_a_lot to possibly spin around for
11596 		 * more increasing tot_len_this_send to the point
11597 		 * that its going to require a pace, or we hit the
11598 		 * cwnd. Which in that case we are just waiting for
11599 		 * a ACK.
11600 		 */
11601 		slot = len / tr_perms;
11602 		/* Now do we reduce the time so we don't run dry? */
11603 		if (slot && rack_slot_reduction) {
11604 			reduce = (slot / rack_slot_reduction);
11605 			if (reduce < slot) {
11606 				slot -= reduce;
11607 			} else
11608 				slot = 0;
11609 		}
11610 		slot *=  HPTS_USEC_IN_MSEC;
11611 		if (rsm == NULL) {
11612 			/*
11613 			 * We always consider ourselves app limited with old style
11614 			 * that are not retransmits. This could be the initial
11615 			 * measurement, but thats ok its all setup and specially
11616 			 * handled. If another send leaks out, then that too will
11617 			 * be mark app-limited.
11618 			 */
11619 			lrsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
11620 			if (lrsm && ((lrsm->r_flags & RACK_APP_LIMITED) == 0)) {
11621 				rack->r_ctl.rc_first_appl = lrsm;
11622 				lrsm->r_flags |= RACK_APP_LIMITED;
11623 				rack->r_ctl.rc_app_limited_cnt++;
11624 			}
11625 		}
11626 		rack_log_pacing_delay_calc(rack, len, slot, tr_perms, reduce, 0, 7, __LINE__, NULL);
11627 	} else {
11628 		uint64_t bw_est, res, lentim, rate_wanted;
11629 		uint32_t orig_val, srtt, segs, oh;
11630 
11631 		if ((rack->r_rr_config == 1) && rsm) {
11632 			return (rack->r_ctl.rc_min_to * HPTS_USEC_IN_MSEC);
11633 		}
11634 		if (rack->use_fixed_rate) {
11635 			rate_wanted = bw_est = rack_get_fixed_pacing_bw(rack);
11636 		} else if ((rack->r_ctl.init_rate == 0) &&
11637 #ifdef NETFLIX_PEAKRATE
11638 			   (rack->rc_tp->t_maxpeakrate == 0) &&
11639 #endif
11640 			   (rack->r_ctl.gp_bw == 0)) {
11641 			/* no way to yet do an estimate */
11642 			bw_est = rate_wanted = 0;
11643 		} else {
11644 			bw_est = rack_get_bw(rack);
11645 			rate_wanted = rack_get_output_bw(rack, bw_est, rsm);
11646 		}
11647 		if ((bw_est == 0) || (rate_wanted == 0)) {
11648 			/*
11649 			 * No way yet to make a b/w estimate or
11650 			 * our raise is set incorrectly.
11651 			 */
11652 			goto old_method;
11653 		}
11654 		/* We need to account for all the overheads */
11655 		segs = (len + segsiz - 1) / segsiz;
11656 		/*
11657 		 * We need the diff between 1514 bytes (e-mtu with e-hdr)
11658 		 * and how much data we put in each packet. Yes this
11659 		 * means we may be off if we are larger than 1500 bytes
11660 		 * or smaller. But this just makes us more conservative.
11661 		 */
11662 		if (ETHERNET_SEGMENT_SIZE > segsiz)
11663 			oh = ETHERNET_SEGMENT_SIZE - segsiz;
11664 		else
11665 			oh = 0;
11666 		segs *= oh;
11667 		lentim = (uint64_t)(len + segs)  * (uint64_t)HPTS_USEC_IN_SEC;
11668 		res = lentim / rate_wanted;
11669 		slot = (uint32_t)res;
11670 		orig_val = rack->r_ctl.rc_pace_max_segs;
11671 		rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
11672 #ifdef KERN_TLS
11673 		/* For TLS we need to override this, possibly  */
11674 		if (rack->rc_inp->inp_socket->so_snd.sb_flags & SB_TLS_IFNET) {
11675 			rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
11676 		}
11677 #endif
11678 		/* Did we change the TSO size, if so log it */
11679 		if (rack->r_ctl.rc_pace_max_segs != orig_val)
11680 			rack_log_pacing_delay_calc(rack, len, slot, orig_val, 0, 0, 15, __LINE__, NULL);
11681 		if ((rack->rc_pace_to_cwnd) &&
11682 		    (rack->in_probe_rtt == 0) &&
11683 		    (IN_RECOVERY(rack->rc_tp->t_flags) == 0)) {
11684 			/*
11685 			 * We want to pace at our rate *or* faster to
11686 			 * fill the cwnd to the max if its not full.
11687 			 */
11688 			slot = pace_to_fill_cwnd(rack, slot, (len+segs), segsiz);
11689 		}
11690 		if ((rack->rc_inp->inp_route.ro_nh != NULL) &&
11691 		    (rack->rc_inp->inp_route.ro_nh->nh_ifp != NULL)) {
11692 			if ((rack->rack_hdw_pace_ena) &&
11693 			    (rack->rack_hdrw_pacing == 0) &&
11694 			    (rack->rack_attempt_hdwr_pace == 0)) {
11695 				/*
11696 				 * Lets attempt to turn on hardware pacing
11697 				 * if we can.
11698 				 */
11699 				rack->rack_attempt_hdwr_pace = 1;
11700 				rack->r_ctl.crte = tcp_set_pacing_rate(rack->rc_tp,
11701 								       rack->rc_inp->inp_route.ro_nh->nh_ifp,
11702 								       rate_wanted,
11703 								       RS_PACING_GEQ,
11704 								       &err);
11705 				if (rack->r_ctl.crte) {
11706 					rack->rack_hdrw_pacing = 1;
11707 					rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(rate_wanted, segsiz,
11708 												 0, rack->r_ctl.crte,
11709 												 NULL);
11710 					rack_log_hdwr_pacing(rack, rack->rc_inp->inp_route.ro_nh->nh_ifp,
11711 							     rate_wanted, rack->r_ctl.crte->rate, __LINE__,
11712 							     err);
11713 				}
11714 			} else if (rack->rack_hdrw_pacing &&
11715 				   (rack->r_ctl.crte->rate != rate_wanted)) {
11716 				/* Do we need to adjust our rate? */
11717 				const struct tcp_hwrate_limit_table *nrte;
11718 
11719 				nrte = tcp_chg_pacing_rate(rack->r_ctl.crte,
11720 							   rack->rc_tp,
11721 							   rack->rc_inp->inp_route.ro_nh->nh_ifp,
11722 							   rate_wanted,
11723 							   RS_PACING_GEQ,
11724 							   &err);
11725 				if (nrte == NULL) {
11726 					/* Lost the rate */
11727 					rack->rack_hdrw_pacing = 0;
11728 					rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
11729 				} else if (nrte != rack->r_ctl.crte) {
11730 					rack->r_ctl.crte = nrte;
11731 					rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(rate_wanted,
11732 												 segsiz, 0,
11733 												 rack->r_ctl.crte,
11734 												 NULL);
11735 					rack_log_hdwr_pacing(rack, rack->rc_inp->inp_route.ro_nh->nh_ifp,
11736 							     rate_wanted, rack->r_ctl.crte->rate, __LINE__,
11737 							     err);
11738 				}
11739 
11740 			}
11741 		}
11742 		if (rack_limit_time_with_srtt &&
11743 		    (rack->use_fixed_rate == 0) &&
11744 #ifdef NETFLIX_PEAKRATE
11745 		    (rack->rc_tp->t_maxpeakrate == 0) &&
11746 #endif
11747 		    (rack->rack_hdrw_pacing == 0)) {
11748 			/*
11749 			 * Sanity check, we do not allow the pacing delay
11750 			 * to be longer than the SRTT of the path. If it is
11751 			 * a slow path, then adding a packet should increase
11752 			 * the RTT and compensate for this i.e. the srtt will
11753 			 * be greater so the allowed pacing time will be greater.
11754 			 *
11755 			 * Note this restriction is not for where a peak rate
11756 			 * is set, we are doing fixed pacing or hardware pacing.
11757 			 */
11758 			if (rack->rc_tp->t_srtt)
11759 				srtt = (TICKS_2_USEC(rack->rc_tp->t_srtt) >> TCP_RTT_SHIFT);
11760 			else
11761 				srtt = RACK_INITIAL_RTO * HPTS_USEC_IN_MSEC;	/* its in ms convert */
11762 			if (srtt < slot) {
11763 				rack_log_pacing_delay_calc(rack, srtt, slot, rate_wanted, bw_est, lentim, 99, __LINE__, NULL);
11764 				slot = srtt;
11765 			}
11766 		}
11767 		rack_log_pacing_delay_calc(rack, len, slot, rate_wanted, bw_est, lentim, 2, __LINE__, rsm);
11768 	}
11769 	if (slot)
11770 		counter_u64_add(rack_calc_nonzero, 1);
11771 	else
11772 		counter_u64_add(rack_calc_zero, 1);
11773 	return (slot);
11774 }
11775 
11776 static void
11777 rack_start_gp_measurement(struct tcpcb *tp, struct tcp_rack *rack,
11778     tcp_seq startseq, uint32_t sb_offset)
11779 {
11780 	struct rack_sendmap *my_rsm = NULL;
11781 	struct rack_sendmap fe;
11782 
11783 	if (tp->t_state < TCPS_ESTABLISHED) {
11784 		/*
11785 		 * We don't start any measurements if we are
11786 		 * not at least established.
11787 		 */
11788 		return;
11789 	}
11790 	tp->t_flags |= TF_GPUTINPROG;
11791 	rack->r_ctl.rc_gp_lowrtt = 0xffffffff;
11792 	rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
11793 	tp->gput_seq = startseq;
11794 	rack->app_limited_needs_set = 0;
11795 	if (rack->in_probe_rtt)
11796 		rack->measure_saw_probe_rtt = 1;
11797 	else if ((rack->measure_saw_probe_rtt) &&
11798 		 (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
11799 		rack->measure_saw_probe_rtt = 0;
11800 	if (rack->rc_gp_filled)
11801 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
11802 	else {
11803 		/* Special case initial measurement */
11804 		rack->r_ctl.rc_gp_output_ts = tp->gput_ts = tcp_get_usecs(NULL);
11805 	}
11806 	/*
11807 	 * We take a guess out into the future,
11808 	 * if we have no measurement and no
11809 	 * initial rate, we measure the first
11810 	 * initial-windows worth of data to
11811 	 * speed up getting some GP measurement and
11812 	 * thus start pacing.
11813 	 */
11814 	if ((rack->rc_gp_filled == 0) && (rack->r_ctl.init_rate == 0)) {
11815 		rack->app_limited_needs_set = 1;
11816 		tp->gput_ack = startseq + max(rc_init_window(rack),
11817 					      (MIN_GP_WIN * ctf_fixed_maxseg(tp)));
11818 		rack_log_pacing_delay_calc(rack,
11819 					   tp->gput_seq,
11820 					   tp->gput_ack,
11821 					   0,
11822 					   tp->gput_ts,
11823 					   rack->r_ctl.rc_app_limited_cnt,
11824 					   9,
11825 					   __LINE__, NULL);
11826 		return;
11827 	}
11828 	if (sb_offset) {
11829 		/*
11830 		 * We are out somewhere in the sb
11831 		 * can we use the already outstanding data?
11832 		 */
11833 
11834 		if (rack->r_ctl.rc_app_limited_cnt == 0) {
11835 			/*
11836 			 * Yes first one is good and in this case
11837 			 * the tp->gput_ts is correctly set based on
11838 			 * the last ack that arrived (no need to
11839 			 * set things up when an ack comes in).
11840 			 */
11841 			my_rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
11842 			if ((my_rsm == NULL) ||
11843 			    (my_rsm->r_rtr_cnt != 1)) {
11844 				/* retransmission? */
11845 				goto use_latest;
11846 			}
11847 		} else {
11848 			if (rack->r_ctl.rc_first_appl == NULL) {
11849 				/*
11850 				 * If rc_first_appl is NULL
11851 				 * then the cnt should be 0.
11852 				 * This is probably an error, maybe
11853 				 * a KASSERT would be approprate.
11854 				 */
11855 				goto use_latest;
11856 			}
11857 			/*
11858 			 * If we have a marker pointer to the last one that is
11859 			 * app limited we can use that, but we need to set
11860 			 * things up so that when it gets ack'ed we record
11861 			 * the ack time (if its not already acked).
11862 			 */
11863 			rack->app_limited_needs_set = 1;
11864 			/*
11865 			 * We want to get to the rsm that is either
11866 			 * next with space i.e. over 1 MSS or the one
11867 			 * after that (after the app-limited).
11868 			 */
11869 			my_rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree,
11870 					 rack->r_ctl.rc_first_appl);
11871 			if (my_rsm) {
11872 				if ((my_rsm->r_end - my_rsm->r_start) <= ctf_fixed_maxseg(tp))
11873 					/* Have to use the next one */
11874 					my_rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree,
11875 							 my_rsm);
11876 				else {
11877 					/* Use after the first MSS of it is acked */
11878 					tp->gput_seq = my_rsm->r_start + ctf_fixed_maxseg(tp);
11879 					goto start_set;
11880 				}
11881 			}
11882 			if ((my_rsm == NULL) ||
11883 			    (my_rsm->r_rtr_cnt != 1)) {
11884 				/*
11885 				 * Either its a retransmit or
11886 				 * the last is the app-limited one.
11887 				 */
11888 				goto use_latest;
11889 			}
11890 		}
11891 		tp->gput_seq = my_rsm->r_start;
11892 start_set:
11893 		if (my_rsm->r_flags & RACK_ACKED) {
11894 			/*
11895 			 * This one has been acked use the arrival ack time
11896 			 */
11897 			tp->gput_ts = my_rsm->r_ack_arrival;
11898 			rack->app_limited_needs_set = 0;
11899 		}
11900 		rack->r_ctl.rc_gp_output_ts = my_rsm->usec_orig_send;
11901 		tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
11902 		rack_log_pacing_delay_calc(rack,
11903 					   tp->gput_seq,
11904 					   tp->gput_ack,
11905 					   (uint64_t)my_rsm,
11906 					   tp->gput_ts,
11907 					   rack->r_ctl.rc_app_limited_cnt,
11908 					   9,
11909 					   __LINE__, NULL);
11910 		return;
11911 	}
11912 
11913 use_latest:
11914 	/*
11915 	 * We don't know how long we may have been
11916 	 * idle or if this is the first-send. Lets
11917 	 * setup the flag so we will trim off
11918 	 * the first ack'd data so we get a true
11919 	 * measurement.
11920 	 */
11921 	rack->app_limited_needs_set = 1;
11922 	tp->gput_ack = startseq + rack_get_measure_window(tp, rack);
11923 	/* Find this guy so we can pull the send time */
11924 	fe.r_start = startseq;
11925 	my_rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
11926 	if (my_rsm) {
11927 		rack->r_ctl.rc_gp_output_ts = my_rsm->usec_orig_send;
11928 		if (my_rsm->r_flags & RACK_ACKED) {
11929 			/*
11930 			 * Unlikely since its probably what was
11931 			 * just transmitted (but I am paranoid).
11932 			 */
11933 			tp->gput_ts = my_rsm->r_ack_arrival;
11934 			rack->app_limited_needs_set = 0;
11935 		}
11936 		if (SEQ_LT(my_rsm->r_start, tp->gput_seq)) {
11937 			/* This also is unlikely */
11938 			tp->gput_seq = my_rsm->r_start;
11939 		}
11940 	} else {
11941 		/*
11942 		 * TSNH unless we have some send-map limit,
11943 		 * and even at that it should not be hitting
11944 		 * that limit (we should have stopped sending).
11945 		 */
11946 		rack->r_ctl.rc_gp_output_ts = tcp_get_usecs(NULL);
11947 	}
11948 	rack_log_pacing_delay_calc(rack,
11949 				   tp->gput_seq,
11950 				   tp->gput_ack,
11951 				   (uint64_t)my_rsm,
11952 				   tp->gput_ts,
11953 				   rack->r_ctl.rc_app_limited_cnt,
11954 				   9, __LINE__, NULL);
11955 }
11956 
11957 static inline uint32_t
11958 rack_what_can_we_send(struct tcpcb *tp, struct tcp_rack *rack,  uint32_t cwnd_to_use,
11959     uint32_t avail, int32_t sb_offset)
11960 {
11961 	uint32_t len;
11962 	uint32_t sendwin;
11963 
11964 	if (tp->snd_wnd > cwnd_to_use)
11965 		sendwin = cwnd_to_use;
11966 	else
11967 		sendwin = tp->snd_wnd;
11968 	if (ctf_outstanding(tp) >= tp->snd_wnd) {
11969 		/* We never want to go over our peers rcv-window */
11970 		len = 0;
11971 	} else {
11972 		uint32_t flight;
11973 
11974 		flight = ctf_flight_size(tp, rack->r_ctl.rc_sacked);
11975 		if (flight >= sendwin) {
11976 			/*
11977 			 * We have in flight what we are allowed by cwnd (if
11978 			 * it was rwnd blocking it would have hit above out
11979 			 * >= tp->snd_wnd).
11980 			 */
11981 			return (0);
11982 		}
11983 		len = sendwin - flight;
11984 		if ((len + ctf_outstanding(tp)) > tp->snd_wnd) {
11985 			/* We would send too much (beyond the rwnd) */
11986 			len = tp->snd_wnd - ctf_outstanding(tp);
11987 		}
11988 		if ((len + sb_offset) > avail) {
11989 			/*
11990 			 * We don't have that much in the SB, how much is
11991 			 * there?
11992 			 */
11993 			len = avail - sb_offset;
11994 		}
11995 	}
11996 	return (len);
11997 }
11998 
11999 static int
12000 rack_output(struct tcpcb *tp)
12001 {
12002 	struct socket *so;
12003 	uint32_t recwin;
12004 	uint32_t sb_offset;
12005 	int32_t len, flags, error = 0;
12006 	struct mbuf *m;
12007 	struct mbuf *mb;
12008 	uint32_t if_hw_tsomaxsegcount = 0;
12009 	uint32_t if_hw_tsomaxsegsize;
12010 	int32_t segsiz, minseg;
12011 	long tot_len_this_send = 0;
12012 	struct ip *ip = NULL;
12013 #ifdef TCPDEBUG
12014 	struct ipovly *ipov = NULL;
12015 #endif
12016 	struct udphdr *udp = NULL;
12017 	struct tcp_rack *rack;
12018 	struct tcphdr *th;
12019 	uint8_t pass = 0;
12020 	uint8_t mark = 0;
12021 	uint8_t wanted_cookie = 0;
12022 	u_char opt[TCP_MAXOLEN];
12023 	unsigned ipoptlen, optlen, hdrlen, ulen=0;
12024 	uint32_t rack_seq;
12025 
12026 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
12027 	unsigned ipsec_optlen = 0;
12028 
12029 #endif
12030 	int32_t idle, sendalot;
12031 	int32_t sub_from_prr = 0;
12032 	volatile int32_t sack_rxmit;
12033 	struct rack_sendmap *rsm = NULL;
12034 	int32_t tso, mtu;
12035 	struct tcpopt to;
12036 	int32_t slot = 0;
12037 	int32_t sup_rack = 0;
12038 	uint32_t cts, us_cts, delayed, early;
12039 	uint8_t hpts_calling, new_data_tlp = 0, doing_tlp = 0;
12040 	uint32_t cwnd_to_use;
12041 	int32_t do_a_prefetch;
12042 	int32_t prefetch_rsm = 0;
12043 	int force_tso = 0;
12044 	int32_t orig_len;
12045 	struct timeval tv;
12046 	int32_t prefetch_so_done = 0;
12047 	struct tcp_log_buffer *lgb = NULL;
12048 	struct inpcb *inp;
12049 	struct sockbuf *sb;
12050 #ifdef INET6
12051 	struct ip6_hdr *ip6 = NULL;
12052 	int32_t isipv6;
12053 #endif
12054 	uint8_t filled_all = 0;
12055 	bool hw_tls = false;
12056 
12057 	/* setup and take the cache hits here */
12058 	rack = (struct tcp_rack *)tp->t_fb_ptr;
12059 	inp = rack->rc_inp;
12060 	so = inp->inp_socket;
12061 	sb = &so->so_snd;
12062 	kern_prefetch(sb, &do_a_prefetch);
12063 	do_a_prefetch = 1;
12064 	hpts_calling = inp->inp_hpts_calls;
12065 #ifdef KERN_TLS
12066 	hw_tls = (so->so_snd.sb_flags & SB_TLS_IFNET) != 0;
12067 #endif
12068 
12069 	NET_EPOCH_ASSERT();
12070 	INP_WLOCK_ASSERT(inp);
12071 #ifdef TCP_OFFLOAD
12072 	if (tp->t_flags & TF_TOE)
12073 		return (tcp_offload_output(tp));
12074 #endif
12075 	/*
12076 	 * For TFO connections in SYN_RECEIVED, only allow the initial
12077 	 * SYN|ACK and those sent by the retransmit timer.
12078 	 */
12079 	if (IS_FASTOPEN(tp->t_flags) &&
12080 	    (tp->t_state == TCPS_SYN_RECEIVED) &&
12081 	    SEQ_GT(tp->snd_max, tp->snd_una) &&    /* initial SYN|ACK sent */
12082 	    (rack->r_ctl.rc_resend == NULL))         /* not a retransmit */
12083 		return (0);
12084 #ifdef INET6
12085 	if (rack->r_state) {
12086 		/* Use the cache line loaded if possible */
12087 		isipv6 = rack->r_is_v6;
12088 	} else {
12089 		isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
12090 	}
12091 #endif
12092 	early = 0;
12093 	us_cts = tcp_get_usecs(&tv);
12094 	cts = tcp_tv_to_mssectick(&tv);
12095 	if (((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0) &&
12096 	    inp->inp_in_hpts) {
12097 		/*
12098 		 * We are on the hpts for some timer but not hptsi output.
12099 		 * Remove from the hpts unconditionally.
12100 		 */
12101 		rack_timer_cancel(tp, rack, cts, __LINE__);
12102 	}
12103 	/* Are we pacing and late? */
12104 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
12105 	    TSTMP_GEQ(us_cts, rack->r_ctl.rc_last_output_to)) {
12106 		/* We are delayed */
12107 		delayed = us_cts - rack->r_ctl.rc_last_output_to;
12108 	} else {
12109 		delayed = 0;
12110 	}
12111 	/* Do the timers, which may override the pacer  */
12112 	if (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
12113 		if (rack_process_timers(tp, rack, cts, hpts_calling)) {
12114 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_ATIMER], 1);
12115 			return (0);
12116 		}
12117 	}
12118 	if ((rack->r_timer_override) ||
12119 	    (delayed) ||
12120 	    (tp->t_state < TCPS_ESTABLISHED)) {
12121 		if (tp->t_inpcb->inp_in_hpts)
12122 			tcp_hpts_remove(tp->t_inpcb, HPTS_REMOVE_OUTPUT);
12123 	} else if (tp->t_inpcb->inp_in_hpts) {
12124 		/*
12125 		 * On the hpts you can't pass even if ACKNOW is on, we will
12126 		 * when the hpts fires.
12127 		 */
12128 		counter_u64_add(rack_out_size[TCP_MSS_ACCT_INPACE], 1);
12129 		return (0);
12130 	}
12131 	inp->inp_hpts_calls = 0;
12132 	/* Finish out both pacing early and late accounting */
12133 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
12134 	    TSTMP_GT(rack->r_ctl.rc_last_output_to, us_cts)) {
12135 		early = rack->r_ctl.rc_last_output_to - us_cts;
12136 	} else
12137 		early = 0;
12138 	if (delayed) {
12139 		rack->r_ctl.rc_agg_delayed += delayed;
12140 		rack->r_late = 1;
12141 	} else if (early) {
12142 		rack->r_ctl.rc_agg_early += early;
12143 		rack->r_early = 1;
12144 	}
12145 	/* Now that early/late accounting is done turn off the flag */
12146 	rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
12147 	rack->r_wanted_output = 0;
12148 	rack->r_timer_override = 0;
12149 	/*
12150 	 * For TFO connections in SYN_SENT or SYN_RECEIVED,
12151 	 * only allow the initial SYN or SYN|ACK and those sent
12152 	 * by the retransmit timer.
12153 	 */
12154 	if (IS_FASTOPEN(tp->t_flags) &&
12155 	    ((tp->t_state == TCPS_SYN_RECEIVED) ||
12156 	     (tp->t_state == TCPS_SYN_SENT)) &&
12157 	    SEQ_GT(tp->snd_max, tp->snd_una) && /* initial SYN or SYN|ACK sent */
12158 	    (tp->t_rxtshift == 0)) {              /* not a retransmit */
12159 		cwnd_to_use = rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
12160 		goto just_return_nolock;
12161 	}
12162 	/*
12163 	 * Determine length of data that should be transmitted, and flags
12164 	 * that will be used. If there is some data or critical controls
12165 	 * (SYN, RST) to send, then transmit; otherwise, investigate
12166 	 * further.
12167 	 */
12168 	idle = (tp->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una);
12169 	if (tp->t_idle_reduce) {
12170 		if (idle && ((ticks - tp->t_rcvtime) >= tp->t_rxtcur))
12171 			rack_cc_after_idle(rack, tp);
12172 	}
12173 	tp->t_flags &= ~TF_LASTIDLE;
12174 	if (idle) {
12175 		if (tp->t_flags & TF_MORETOCOME) {
12176 			tp->t_flags |= TF_LASTIDLE;
12177 			idle = 0;
12178 		}
12179 	}
12180 	if ((tp->snd_una == tp->snd_max) &&
12181 	    rack->r_ctl.rc_went_idle_time &&
12182 	    TSTMP_GT(us_cts, rack->r_ctl.rc_went_idle_time)) {
12183 		idle = us_cts - rack->r_ctl.rc_went_idle_time;
12184 		if (idle > rack_min_probertt_hold) {
12185 			/* Count as a probe rtt */
12186 			if (rack->in_probe_rtt == 0) {
12187 				rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
12188 				rack->r_ctl.rc_time_probertt_entered = rack->r_ctl.rc_lower_rtt_us_cts;
12189 				rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts;
12190 				rack->r_ctl.rc_time_of_last_probertt = rack->r_ctl.rc_lower_rtt_us_cts;
12191 			} else {
12192 				rack_exit_probertt(rack, us_cts);
12193 			}
12194 		}
12195 		idle = 0;
12196 	}
12197 again:
12198 	/*
12199 	 * If we've recently taken a timeout, snd_max will be greater than
12200 	 * snd_nxt.  There may be SACK information that allows us to avoid
12201 	 * resending already delivered data.  Adjust snd_nxt accordingly.
12202 	 */
12203 	sendalot = 0;
12204 	us_cts = tcp_get_usecs(&tv);
12205 	cts = tcp_tv_to_mssectick(&tv);
12206 	tso = 0;
12207 	mtu = 0;
12208 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
12209 	if (so->so_snd.sb_flags & SB_TLS_IFNET) {
12210 		minseg = rack->r_ctl.rc_pace_min_segs;
12211 	} else {
12212 		minseg = segsiz;
12213 	}
12214 	sb_offset = tp->snd_max - tp->snd_una;
12215 	cwnd_to_use = rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
12216 #ifdef NETFLIX_SHARED_CWND
12217 	if ((tp->t_flags2 & TF2_TCP_SCWND_ALLOWED) &&
12218 	    rack->rack_enable_scwnd) {
12219 		/* We are doing cwnd sharing */
12220 		if (rack->rc_gp_filled &&
12221 		    (rack->rack_attempted_scwnd == 0) &&
12222 		    (rack->r_ctl.rc_scw == NULL) &&
12223 		    tp->t_lib) {
12224 			/* The pcbid is in, lets make an attempt */
12225 			counter_u64_add(rack_try_scwnd, 1);
12226 			rack->rack_attempted_scwnd = 1;
12227 			rack->r_ctl.rc_scw = tcp_shared_cwnd_alloc(tp,
12228 								   &rack->r_ctl.rc_scw_index,
12229 								   segsiz);
12230 		}
12231 		if (rack->r_ctl.rc_scw &&
12232 		    (rack->rack_scwnd_is_idle == 1) &&
12233 		    (rack->rc_in_persist == 0) &&
12234 		    sbavail(sb)) {
12235 			/* we are no longer out of data */
12236 			tcp_shared_cwnd_active(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
12237 			rack->rack_scwnd_is_idle = 0;
12238 		}
12239 		if (rack->r_ctl.rc_scw) {
12240 			/* First lets update and get the cwnd */
12241 			rack->r_ctl.cwnd_to_use = cwnd_to_use = tcp_shared_cwnd_update(rack->r_ctl.rc_scw,
12242 								    rack->r_ctl.rc_scw_index,
12243 								    tp->snd_cwnd, tp->snd_wnd, segsiz);
12244 		}
12245 	}
12246 #endif
12247 	flags = tcp_outflags[tp->t_state];
12248 	while (rack->rc_free_cnt < rack_free_cache) {
12249 		rsm = rack_alloc(rack);
12250 		if (rsm == NULL) {
12251 			if (inp->inp_hpts_calls)
12252 				/* Retry in a ms */
12253 				slot = (1 * HPTS_USEC_IN_MSEC);
12254 			goto just_return_nolock;
12255 		}
12256 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_free, rsm, r_tnext);
12257 		rack->rc_free_cnt++;
12258 		rsm = NULL;
12259 	}
12260 	if (inp->inp_hpts_calls)
12261 		inp->inp_hpts_calls = 0;
12262 	sack_rxmit = 0;
12263 	len = 0;
12264 	rsm = NULL;
12265 	if (flags & TH_RST) {
12266 		SOCKBUF_LOCK(sb);
12267 		goto send;
12268 	}
12269 	if (rack->r_ctl.rc_resend) {
12270 		/* Retransmit timer */
12271 		rsm = rack->r_ctl.rc_resend;
12272 		rack->r_ctl.rc_resend = NULL;
12273 		rsm->r_flags &= ~RACK_TLP;
12274 		len = rsm->r_end - rsm->r_start;
12275 		sack_rxmit = 1;
12276 		sendalot = 0;
12277 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
12278 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
12279 			 __func__, __LINE__,
12280 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
12281 		sb_offset = rsm->r_start - tp->snd_una;
12282 		if (len >= segsiz)
12283 			len = segsiz;
12284 	} else if ((rack->rc_in_persist == 0) &&
12285 		   ((rsm = tcp_rack_output(tp, rack, cts)) != NULL)) {
12286 		/* We have a retransmit that takes precedence */
12287 		rsm->r_flags &= ~RACK_TLP;
12288 		if ((!IN_RECOVERY(tp->t_flags)) &&
12289 		    ((tp->t_flags & (TF_WASFRECOVERY | TF_WASCRECOVERY)) == 0)) {
12290 			/* Enter recovery if not induced by a time-out */
12291 			rack->r_ctl.rc_rsm_start = rsm->r_start;
12292 			rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
12293 			rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
12294 			rack_cong_signal(tp, NULL, CC_NDUPACK);
12295 			/*
12296 			 * When we enter recovery we need to assure we send
12297 			 * one packet.
12298 			 */
12299 			if (rack->rack_no_prr == 0) {
12300 				rack->r_ctl.rc_prr_sndcnt = segsiz;
12301 				rack_log_to_prr(rack, 13, 0);
12302 			}
12303 		}
12304 #ifdef INVARIANTS
12305 		if (SEQ_LT(rsm->r_start, tp->snd_una)) {
12306 			panic("Huh, tp:%p rack:%p rsm:%p start:%u < snd_una:%u\n",
12307 			      tp, rack, rsm, rsm->r_start, tp->snd_una);
12308 		}
12309 #endif
12310 		len = rsm->r_end - rsm->r_start;
12311 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
12312 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
12313 			 __func__, __LINE__,
12314 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
12315 		sb_offset = rsm->r_start - tp->snd_una;
12316 		/* Can we send it within the PRR boundary? */
12317 		if (rack->rack_no_prr == 0) {
12318 			if ((rack->use_rack_rr == 0) && (len > rack->r_ctl.rc_prr_sndcnt)) {
12319 				/* It does not fit */
12320 				if ((ctf_flight_size(tp, rack->r_ctl.rc_sacked) > len) &&
12321 				    (rack->r_ctl.rc_prr_sndcnt < segsiz)) {
12322 					/*
12323 					 * prr is less than a segment, we
12324 					 * have more acks due in besides
12325 					 * what we need to resend. Lets not send
12326 					 * to avoid sending small pieces of
12327 					 * what we need to retransmit.
12328 					 */
12329 					len = 0;
12330 					goto just_return_nolock;
12331 				}
12332 				len = rack->r_ctl.rc_prr_sndcnt;
12333 			}
12334 		}
12335 		sendalot = 0;
12336 		if (len >= segsiz)
12337 			len = segsiz;
12338 		if (len > 0) {
12339 			sub_from_prr = 1;
12340 			sack_rxmit = 1;
12341 			KMOD_TCPSTAT_INC(tcps_sack_rexmits);
12342 			KMOD_TCPSTAT_ADD(tcps_sack_rexmit_bytes,
12343 			    min(len, segsiz));
12344 			counter_u64_add(rack_rtm_prr_retran, 1);
12345 		}
12346 	} else 	if (rack->r_ctl.rc_tlpsend) {
12347 		/* Tail loss probe */
12348 		long cwin;
12349 		long tlen;
12350 
12351 		doing_tlp = 1;
12352 		/*
12353 		 * Check if we can do a TLP with a RACK'd packet
12354 		 * this can happen if we are not doing the rack
12355 		 * cheat and we skipped to a TLP and it
12356 		 * went off.
12357 		 */
12358 		rsm = rack->r_ctl.rc_tlpsend;
12359 		rsm->r_flags |= RACK_TLP;
12360 		rack->r_ctl.rc_tlpsend = NULL;
12361 		sack_rxmit = 1;
12362 		tlen = rsm->r_end - rsm->r_start;
12363 		if (tlen > segsiz)
12364 			tlen = segsiz;
12365 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
12366 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
12367 			 __func__, __LINE__,
12368 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
12369 		sb_offset = rsm->r_start - tp->snd_una;
12370 		cwin = min(tp->snd_wnd, tlen);
12371 		len = cwin;
12372 	}
12373 	/*
12374 	 * Enforce a connection sendmap count limit if set
12375 	 * as long as we are not retransmiting.
12376 	 */
12377 	if ((rsm == NULL) &&
12378 	    (rack->do_detection == 0) &&
12379 	    (V_tcp_map_entries_limit > 0) &&
12380 	    (rack->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
12381 		counter_u64_add(rack_to_alloc_limited, 1);
12382 		if (!rack->alloc_limit_reported) {
12383 			rack->alloc_limit_reported = 1;
12384 			counter_u64_add(rack_alloc_limited_conns, 1);
12385 		}
12386 		goto just_return_nolock;
12387 	}
12388 	if (rsm && (rsm->r_flags & RACK_HAS_FIN)) {
12389 		/* we are retransmitting the fin */
12390 		len--;
12391 		if (len) {
12392 			/*
12393 			 * When retransmitting data do *not* include the
12394 			 * FIN. This could happen from a TLP probe.
12395 			 */
12396 			flags &= ~TH_FIN;
12397 		}
12398 	}
12399 #ifdef INVARIANTS
12400 	/* For debugging */
12401 	rack->r_ctl.rc_rsm_at_retran = rsm;
12402 #endif
12403 	/*
12404 	 * Get standard flags, and add SYN or FIN if requested by 'hidden'
12405 	 * state flags.
12406 	 */
12407 	if (tp->t_flags & TF_NEEDFIN)
12408 		flags |= TH_FIN;
12409 	if (tp->t_flags & TF_NEEDSYN)
12410 		flags |= TH_SYN;
12411 	if ((sack_rxmit == 0) && (prefetch_rsm == 0)) {
12412 		void *end_rsm;
12413 		end_rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_tmap, rack_sendmap, r_tnext);
12414 		if (end_rsm)
12415 			kern_prefetch(end_rsm, &prefetch_rsm);
12416 		prefetch_rsm = 1;
12417 	}
12418 	SOCKBUF_LOCK(sb);
12419 	/*
12420 	 * If snd_nxt == snd_max and we have transmitted a FIN, the
12421 	 * sb_offset will be > 0 even if so_snd.sb_cc is 0, resulting in a
12422 	 * negative length.  This can also occur when TCP opens up its
12423 	 * congestion window while receiving additional duplicate acks after
12424 	 * fast-retransmit because TCP will reset snd_nxt to snd_max after
12425 	 * the fast-retransmit.
12426 	 *
12427 	 * In the normal retransmit-FIN-only case, however, snd_nxt will be
12428 	 * set to snd_una, the sb_offset will be 0, and the length may wind
12429 	 * up 0.
12430 	 *
12431 	 * If sack_rxmit is true we are retransmitting from the scoreboard
12432 	 * in which case len is already set.
12433 	 */
12434 	if ((sack_rxmit == 0) && TCPS_HAVEESTABLISHED(tp->t_state)) {
12435 		uint32_t avail;
12436 
12437 		avail = sbavail(sb);
12438 		if (SEQ_GT(tp->snd_nxt, tp->snd_una) && avail)
12439 			sb_offset = tp->snd_nxt - tp->snd_una;
12440 		else
12441 			sb_offset = 0;
12442 		if ((IN_RECOVERY(tp->t_flags) == 0) || rack->rack_no_prr) {
12443 			if (rack->r_ctl.rc_tlp_new_data) {
12444 				/* TLP is forcing out new data */
12445 				if (rack->r_ctl.rc_tlp_new_data > (uint32_t) (avail - sb_offset)) {
12446 					rack->r_ctl.rc_tlp_new_data = (uint32_t) (avail - sb_offset);
12447 				}
12448 				if (rack->r_ctl.rc_tlp_new_data > tp->snd_wnd)
12449 					len = tp->snd_wnd;
12450 				else
12451 					len = rack->r_ctl.rc_tlp_new_data;
12452 				rack->r_ctl.rc_tlp_new_data = 0;
12453 				new_data_tlp = doing_tlp = 1;
12454 			}  else
12455 				len = rack_what_can_we_send(tp, rack, cwnd_to_use, avail, sb_offset);
12456 			if (IN_RECOVERY(tp->t_flags) && (len > segsiz)) {
12457 				/*
12458 				 * For prr=off, we need to send only 1 MSS
12459 				 * at a time. We do this because another sack could
12460 				 * be arriving that causes us to send retransmits and
12461 				 * we don't want to be on a long pace due to a larger send
12462 				 * that keeps us from sending out the retransmit.
12463 				 */
12464 				len = segsiz;
12465 			}
12466 		} else {
12467 			uint32_t outstanding;
12468 
12469 			/*
12470 			 * We are inside of a SACK recovery episode and are
12471 			 * sending new data, having retransmitted all the
12472 			 * data possible so far in the scoreboard.
12473 			 */
12474 			outstanding = tp->snd_max - tp->snd_una;
12475 			if ((rack->r_ctl.rc_prr_sndcnt + outstanding) > tp->snd_wnd) {
12476 				if (tp->snd_wnd > outstanding) {
12477 					len = tp->snd_wnd - outstanding;
12478 					/* Check to see if we have the data */
12479 					if ((sb_offset + len) > avail) {
12480 						/* It does not all fit */
12481 						if (avail > sb_offset)
12482 							len = avail - sb_offset;
12483 						else
12484 							len = 0;
12485 					}
12486 				} else
12487 					len = 0;
12488 			} else if (avail > sb_offset)
12489 				len = avail - sb_offset;
12490 			else
12491 				len = 0;
12492 			if (len > 0) {
12493 				if (len > rack->r_ctl.rc_prr_sndcnt)
12494 					len = rack->r_ctl.rc_prr_sndcnt;
12495 				if (len > 0) {
12496 					sub_from_prr = 1;
12497 					counter_u64_add(rack_rtm_prr_newdata, 1);
12498 				}
12499 			}
12500 			if (len > segsiz) {
12501 				/*
12502 				 * We should never send more than a MSS when
12503 				 * retransmitting or sending new data in prr
12504 				 * mode unless the override flag is on. Most
12505 				 * likely the PRR algorithm is not going to
12506 				 * let us send a lot as well :-)
12507 				 */
12508 				if (rack->r_ctl.rc_prr_sendalot == 0)
12509 					len = segsiz;
12510 			} else if (len < segsiz) {
12511 				/*
12512 				 * Do we send any? The idea here is if the
12513 				 * send empty's the socket buffer we want to
12514 				 * do it. However if not then lets just wait
12515 				 * for our prr_sndcnt to get bigger.
12516 				 */
12517 				long leftinsb;
12518 
12519 				leftinsb = sbavail(sb) - sb_offset;
12520 				if (leftinsb > len) {
12521 					/* This send does not empty the sb */
12522 					len = 0;
12523 				}
12524 			}
12525 		}
12526 	} else if (!TCPS_HAVEESTABLISHED(tp->t_state)) {
12527 		/*
12528 		 * If you have not established
12529 		 * and are not doing FAST OPEN
12530 		 * no data please.
12531 		 */
12532 		if ((sack_rxmit == 0) &&
12533 		    (!IS_FASTOPEN(tp->t_flags))){
12534 			len = 0;
12535 			sb_offset = 0;
12536 		}
12537 	}
12538 	if (prefetch_so_done == 0) {
12539 		kern_prefetch(so, &prefetch_so_done);
12540 		prefetch_so_done = 1;
12541 	}
12542 	/*
12543 	 * Lop off SYN bit if it has already been sent.  However, if this is
12544 	 * SYN-SENT state and if segment contains data and if we don't know
12545 	 * that foreign host supports TAO, suppress sending segment.
12546 	 */
12547 	if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una) &&
12548 	    ((sack_rxmit == 0) && (tp->t_rxtshift == 0))) {
12549 		/*
12550 		 * When sending additional segments following a TFO SYN|ACK,
12551 		 * do not include the SYN bit.
12552 		 */
12553 		if (IS_FASTOPEN(tp->t_flags) &&
12554 		    (tp->t_state == TCPS_SYN_RECEIVED))
12555 			flags &= ~TH_SYN;
12556 	}
12557 	/*
12558 	 * Be careful not to send data and/or FIN on SYN segments. This
12559 	 * measure is needed to prevent interoperability problems with not
12560 	 * fully conformant TCP implementations.
12561 	 */
12562 	if ((flags & TH_SYN) && (tp->t_flags & TF_NOOPT)) {
12563 		len = 0;
12564 		flags &= ~TH_FIN;
12565 	}
12566 	/*
12567 	 * On TFO sockets, ensure no data is sent in the following cases:
12568 	 *
12569 	 *  - When retransmitting SYN|ACK on a passively-created socket
12570 	 *
12571 	 *  - When retransmitting SYN on an actively created socket
12572 	 *
12573 	 *  - When sending a zero-length cookie (cookie request) on an
12574 	 *    actively created socket
12575 	 *
12576 	 *  - When the socket is in the CLOSED state (RST is being sent)
12577 	 */
12578 	if (IS_FASTOPEN(tp->t_flags) &&
12579 	    (((flags & TH_SYN) && (tp->t_rxtshift > 0)) ||
12580 	     ((tp->t_state == TCPS_SYN_SENT) &&
12581 	      (tp->t_tfo_client_cookie_len == 0)) ||
12582 	     (flags & TH_RST))) {
12583 		sack_rxmit = 0;
12584 		len = 0;
12585 	}
12586 	/* Without fast-open there should never be data sent on a SYN */
12587 	if ((flags & TH_SYN) && (!IS_FASTOPEN(tp->t_flags))) {
12588 		tp->snd_nxt = tp->iss;
12589 		len = 0;
12590 	}
12591 	orig_len = len;
12592 	if (len <= 0) {
12593 		/*
12594 		 * If FIN has been sent but not acked, but we haven't been
12595 		 * called to retransmit, len will be < 0.  Otherwise, window
12596 		 * shrank after we sent into it.  If window shrank to 0,
12597 		 * cancel pending retransmit, pull snd_nxt back to (closed)
12598 		 * window, and set the persist timer if it isn't already
12599 		 * going.  If the window didn't close completely, just wait
12600 		 * for an ACK.
12601 		 *
12602 		 * We also do a general check here to ensure that we will
12603 		 * set the persist timer when we have data to send, but a
12604 		 * 0-byte window. This makes sure the persist timer is set
12605 		 * even if the packet hits one of the "goto send" lines
12606 		 * below.
12607 		 */
12608 		len = 0;
12609 		if ((tp->snd_wnd == 0) &&
12610 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
12611 		    (tp->snd_una == tp->snd_max) &&
12612 		    (sb_offset < (int)sbavail(sb))) {
12613 			tp->snd_nxt = tp->snd_una;
12614 			rack_enter_persist(tp, rack, cts);
12615 		}
12616 	} else if ((rsm == NULL) &&
12617 		   ((doing_tlp == 0) || (new_data_tlp == 1)) &&
12618 		   (len < rack->r_ctl.rc_pace_max_segs)) {
12619 		/*
12620 		 * We are not sending a maximum sized segment for
12621 		 * some reason. Should we not send anything (think
12622 		 * sws or persists)?
12623 		 */
12624 		if ((tp->snd_wnd < min(max(segsiz, (rack->r_ctl.rc_high_rwnd/2)), minseg)) &&
12625 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
12626 		    (len < minseg) &&
12627 		    (len < (int)(sbavail(sb) - sb_offset))) {
12628 			/*
12629 			 * Here the rwnd is less than
12630 			 * the minimum pacing size, this is not a retransmit,
12631 			 * we are established and
12632 			 * the send is not the last in the socket buffer
12633 			 * we send nothing, and we may enter persists
12634 			 * if nothing is outstanding.
12635 			 */
12636 			len = 0;
12637 			if (tp->snd_max == tp->snd_una) {
12638 				/*
12639 				 * Nothing out we can
12640 				 * go into persists.
12641 				 */
12642 				rack_enter_persist(tp, rack, cts);
12643 				tp->snd_nxt = tp->snd_una;
12644 			}
12645 		} else if ((cwnd_to_use >= max(minseg, (segsiz * 4))) &&
12646 			   (ctf_flight_size(tp, rack->r_ctl.rc_sacked) > (2 * segsiz)) &&
12647 			   (len < (int)(sbavail(sb) - sb_offset)) &&
12648 			   (len < minseg)) {
12649 			/*
12650 			 * Here we are not retransmitting, and
12651 			 * the cwnd is not so small that we could
12652 			 * not send at least a min size (rxt timer
12653 			 * not having gone off), We have 2 segments or
12654 			 * more already in flight, its not the tail end
12655 			 * of the socket buffer  and the cwnd is blocking
12656 			 * us from sending out a minimum pacing segment size.
12657 			 * Lets not send anything.
12658 			 */
12659 			len = 0;
12660 		} else if (((tp->snd_wnd - ctf_outstanding(tp)) <
12661 			    min((rack->r_ctl.rc_high_rwnd/2), minseg)) &&
12662 			   (ctf_flight_size(tp, rack->r_ctl.rc_sacked) > (2 * segsiz)) &&
12663 			   (len < (int)(sbavail(sb) - sb_offset)) &&
12664 			   (TCPS_HAVEESTABLISHED(tp->t_state))) {
12665 			/*
12666 			 * Here we have a send window but we have
12667 			 * filled it up and we can't send another pacing segment.
12668 			 * We also have in flight more than 2 segments
12669 			 * and we are not completing the sb i.e. we allow
12670 			 * the last bytes of the sb to go out even if
12671 			 * its not a full pacing segment.
12672 			 */
12673 			len = 0;
12674 		}
12675 	}
12676 	/* len will be >= 0 after this point. */
12677 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
12678 	tcp_sndbuf_autoscale(tp, so, min(tp->snd_wnd, cwnd_to_use));
12679 	/*
12680 	 * Decide if we can use TCP Segmentation Offloading (if supported by
12681 	 * hardware).
12682 	 *
12683 	 * TSO may only be used if we are in a pure bulk sending state.  The
12684 	 * presence of TCP-MD5, SACK retransmits, SACK advertizements and IP
12685 	 * options prevent using TSO.  With TSO the TCP header is the same
12686 	 * (except for the sequence number) for all generated packets.  This
12687 	 * makes it impossible to transmit any options which vary per
12688 	 * generated segment or packet.
12689 	 *
12690 	 * IPv4 handling has a clear separation of ip options and ip header
12691 	 * flags while IPv6 combines both in in6p_outputopts. ip6_optlen() does
12692 	 * the right thing below to provide length of just ip options and thus
12693 	 * checking for ipoptlen is enough to decide if ip options are present.
12694 	 */
12695 
12696 #ifdef INET6
12697 	if (isipv6)
12698 		ipoptlen = ip6_optlen(tp->t_inpcb);
12699 	else
12700 #endif
12701 		if (tp->t_inpcb->inp_options)
12702 			ipoptlen = tp->t_inpcb->inp_options->m_len -
12703 				offsetof(struct ipoption, ipopt_list);
12704 		else
12705 			ipoptlen = 0;
12706 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
12707 	/*
12708 	 * Pre-calculate here as we save another lookup into the darknesses
12709 	 * of IPsec that way and can actually decide if TSO is ok.
12710 	 */
12711 #ifdef INET6
12712 	if (isipv6 && IPSEC_ENABLED(ipv6))
12713 		ipsec_optlen = IPSEC_HDRSIZE(ipv6, tp->t_inpcb);
12714 #ifdef INET
12715 	else
12716 #endif
12717 #endif				/* INET6 */
12718 #ifdef INET
12719 		if (IPSEC_ENABLED(ipv4))
12720 			ipsec_optlen = IPSEC_HDRSIZE(ipv4, tp->t_inpcb);
12721 #endif				/* INET */
12722 #endif
12723 
12724 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
12725 	ipoptlen += ipsec_optlen;
12726 #endif
12727 	if ((tp->t_flags & TF_TSO) && V_tcp_do_tso && len > segsiz &&
12728 	    (tp->t_port == 0) &&
12729 	    ((tp->t_flags & TF_SIGNATURE) == 0) &&
12730 	    tp->rcv_numsacks == 0 && sack_rxmit == 0 &&
12731 	    ipoptlen == 0)
12732 		tso = 1;
12733 	{
12734 		uint32_t outstanding;
12735 
12736 		outstanding = tp->snd_max - tp->snd_una;
12737 		if (tp->t_flags & TF_SENTFIN) {
12738 			/*
12739 			 * If we sent a fin, snd_max is 1 higher than
12740 			 * snd_una
12741 			 */
12742 			outstanding--;
12743 		}
12744 		if (sack_rxmit) {
12745 			if ((rsm->r_flags & RACK_HAS_FIN) == 0)
12746 				flags &= ~TH_FIN;
12747 		} else {
12748 			if (SEQ_LT(tp->snd_nxt + len, tp->snd_una +
12749 				   sbused(sb)))
12750 				flags &= ~TH_FIN;
12751 		}
12752 	}
12753 	recwin = lmin(lmax(sbspace(&so->so_rcv), 0),
12754 	    (long)TCP_MAXWIN << tp->rcv_scale);
12755 
12756 	/*
12757 	 * Sender silly window avoidance.   We transmit under the following
12758 	 * conditions when len is non-zero:
12759 	 *
12760 	 * - We have a full segment (or more with TSO) - This is the last
12761 	 * buffer in a write()/send() and we are either idle or running
12762 	 * NODELAY - we've timed out (e.g. persist timer) - we have more
12763 	 * then 1/2 the maximum send window's worth of data (receiver may be
12764 	 * limited the window size) - we need to retransmit
12765 	 */
12766 	if (len) {
12767 		if (len >= segsiz) {
12768 			goto send;
12769 		}
12770 		/*
12771 		 * NOTE! on localhost connections an 'ack' from the remote
12772 		 * end may occur synchronously with the output and cause us
12773 		 * to flush a buffer queued with moretocome.  XXX
12774 		 *
12775 		 */
12776 		if (!(tp->t_flags & TF_MORETOCOME) &&	/* normal case */
12777 		    (idle || (tp->t_flags & TF_NODELAY)) &&
12778 		    ((uint32_t)len + (uint32_t)sb_offset >= sbavail(sb)) &&
12779 		    (tp->t_flags & TF_NOPUSH) == 0) {
12780 			pass = 2;
12781 			goto send;
12782 		}
12783 		if ((tp->snd_una == tp->snd_max) && len) {	/* Nothing outstanding */
12784 			pass = 22;
12785 			goto send;
12786 		}
12787 		if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) {
12788 			pass = 4;
12789 			goto send;
12790 		}
12791 		if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {	/* retransmit case */
12792 			pass = 5;
12793 			goto send;
12794 		}
12795 		if (sack_rxmit) {
12796 			pass = 6;
12797 			goto send;
12798 		}
12799 		if (((tp->snd_wnd - ctf_outstanding(tp)) < segsiz) &&
12800 		    (ctf_outstanding(tp) < (segsiz * 2))) {
12801 			/*
12802 			 * We have less than two MSS outstanding (delayed ack)
12803 			 * and our rwnd will not let us send a full sized
12804 			 * MSS. Lets go ahead and let this small segment
12805 			 * out because we want to try to have at least two
12806 			 * packets inflight to not be caught by delayed ack.
12807 			 */
12808 			pass = 12;
12809 			goto send;
12810 		}
12811 	}
12812 	/*
12813 	 * Sending of standalone window updates.
12814 	 *
12815 	 * Window updates are important when we close our window due to a
12816 	 * full socket buffer and are opening it again after the application
12817 	 * reads data from it.  Once the window has opened again and the
12818 	 * remote end starts to send again the ACK clock takes over and
12819 	 * provides the most current window information.
12820 	 *
12821 	 * We must avoid the silly window syndrome whereas every read from
12822 	 * the receive buffer, no matter how small, causes a window update
12823 	 * to be sent.  We also should avoid sending a flurry of window
12824 	 * updates when the socket buffer had queued a lot of data and the
12825 	 * application is doing small reads.
12826 	 *
12827 	 * Prevent a flurry of pointless window updates by only sending an
12828 	 * update when we can increase the advertized window by more than
12829 	 * 1/4th of the socket buffer capacity.  When the buffer is getting
12830 	 * full or is very small be more aggressive and send an update
12831 	 * whenever we can increase by two mss sized segments. In all other
12832 	 * situations the ACK's to new incoming data will carry further
12833 	 * window increases.
12834 	 *
12835 	 * Don't send an independent window update if a delayed ACK is
12836 	 * pending (it will get piggy-backed on it) or the remote side
12837 	 * already has done a half-close and won't send more data.  Skip
12838 	 * this if the connection is in T/TCP half-open state.
12839 	 */
12840 	if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN) &&
12841 	    !(tp->t_flags & TF_DELACK) &&
12842 	    !TCPS_HAVERCVDFIN(tp->t_state)) {
12843 		/*
12844 		 * "adv" is the amount we could increase the window, taking
12845 		 * into account that we are limited by TCP_MAXWIN <<
12846 		 * tp->rcv_scale.
12847 		 */
12848 		int32_t adv;
12849 		int oldwin;
12850 
12851 		adv = recwin;
12852 		if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) {
12853 			oldwin = (tp->rcv_adv - tp->rcv_nxt);
12854 			if (adv > oldwin)
12855 			    adv -= oldwin;
12856 			else {
12857 				/* We can't increase the window */
12858 				adv = 0;
12859 			}
12860 		} else
12861 			oldwin = 0;
12862 
12863 		/*
12864 		 * If the new window size ends up being the same as or less
12865 		 * than the old size when it is scaled, then don't force
12866 		 * a window update.
12867 		 */
12868 		if (oldwin >> tp->rcv_scale >= (adv + oldwin) >> tp->rcv_scale)
12869 			goto dontupdate;
12870 
12871 		if (adv >= (int32_t)(2 * segsiz) &&
12872 		    (adv >= (int32_t)(so->so_rcv.sb_hiwat / 4) ||
12873 		     recwin <= (int32_t)(so->so_rcv.sb_hiwat / 8) ||
12874 		     so->so_rcv.sb_hiwat <= 8 * segsiz)) {
12875 			pass = 7;
12876 			goto send;
12877 		}
12878 		if (2 * adv >= (int32_t) so->so_rcv.sb_hiwat) {
12879 			pass = 23;
12880 			goto send;
12881 		}
12882 	}
12883 dontupdate:
12884 
12885 	/*
12886 	 * Send if we owe the peer an ACK, RST, SYN, or urgent data.  ACKNOW
12887 	 * is also a catch-all for the retransmit timer timeout case.
12888 	 */
12889 	if (tp->t_flags & TF_ACKNOW) {
12890 		pass = 8;
12891 		goto send;
12892 	}
12893 	if (((flags & TH_SYN) && (tp->t_flags & TF_NEEDSYN) == 0)) {
12894 		pass = 9;
12895 		goto send;
12896 	}
12897 	/*
12898 	 * If our state indicates that FIN should be sent and we have not
12899 	 * yet done so, then we need to send.
12900 	 */
12901 	if ((flags & TH_FIN) &&
12902 	    (tp->snd_nxt == tp->snd_una)) {
12903 		pass = 11;
12904 		goto send;
12905 	}
12906 	/*
12907 	 * No reason to send a segment, just return.
12908 	 */
12909 just_return:
12910 	SOCKBUF_UNLOCK(sb);
12911 just_return_nolock:
12912 	{
12913 		int app_limited = CTF_JR_SENT_DATA;
12914 
12915 		if (tot_len_this_send > 0) {
12916 			/* Make sure snd_nxt is up to max */
12917 			if (SEQ_GT(tp->snd_max, tp->snd_nxt))
12918 				tp->snd_nxt = tp->snd_max;
12919 			slot = rack_get_pacing_delay(rack, tp, tot_len_this_send, NULL, segsiz);
12920 		} else {
12921 			int end_window = 0;
12922 			uint32_t seq = tp->gput_ack;
12923 
12924 			rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
12925 			if (rsm) {
12926 				/*
12927 				 * Mark the last sent that we just-returned (hinting
12928 				 * that delayed ack may play a role in any rtt measurement).
12929 				 */
12930 				rsm->r_just_ret = 1;
12931 			}
12932 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_JUSTRET], 1);
12933 			rack->r_ctl.rc_agg_delayed = 0;
12934 			rack->r_early = 0;
12935 			rack->r_late = 0;
12936 			rack->r_ctl.rc_agg_early = 0;
12937 			if ((ctf_outstanding(tp) +
12938 			     min(max(segsiz, (rack->r_ctl.rc_high_rwnd/2)),
12939 				 minseg)) >= tp->snd_wnd) {
12940 				/* We are limited by the rwnd */
12941 				app_limited = CTF_JR_RWND_LIMITED;
12942 			} else if (ctf_outstanding(tp) >= sbavail(sb)) {
12943 				/* We are limited by whats available -- app limited */
12944 				app_limited = CTF_JR_APP_LIMITED;
12945 			} else if ((idle == 0) &&
12946 				   ((tp->t_flags & TF_NODELAY) == 0) &&
12947 				   ((uint32_t)len + (uint32_t)sb_offset >= sbavail(sb)) &&
12948 				   (len < segsiz)) {
12949 				/*
12950 				 * No delay is not on and the
12951 				 * user is sending less than 1MSS. This
12952 				 * brings out SWS avoidance so we
12953 				 * don't send. Another app-limited case.
12954 				 */
12955 				app_limited = CTF_JR_APP_LIMITED;
12956 			} else if (tp->t_flags & TF_NOPUSH) {
12957 				/*
12958 				 * The user has requested no push of
12959 				 * the last segment and we are
12960 				 * at the last segment. Another app
12961 				 * limited case.
12962 				 */
12963 				app_limited = CTF_JR_APP_LIMITED;
12964 			} else if ((ctf_outstanding(tp) + minseg) > cwnd_to_use) {
12965 				/* Its the cwnd */
12966 				app_limited = CTF_JR_CWND_LIMITED;
12967 			} else if (rack->rc_in_persist == 1) {
12968 				/* We are in persists */
12969 				app_limited = CTF_JR_PERSISTS;
12970 			} else if (IN_RECOVERY(tp->t_flags) &&
12971 				   (rack->rack_no_prr == 0) &&
12972 				   (rack->r_ctl.rc_prr_sndcnt < segsiz)) {
12973 				app_limited = CTF_JR_PRR;
12974 			} else {
12975 				/* Now why here are we not sending? */
12976 #ifdef NOW
12977 #ifdef INVARIANTS
12978 				panic("rack:%p hit JR_ASSESSING case cwnd_to_use:%u?", rack, cwnd_to_use);
12979 #endif
12980 #endif
12981 				app_limited = CTF_JR_ASSESSING;
12982 			}
12983 			/*
12984 			 * App limited in some fashion, for our pacing GP
12985 			 * measurements we don't want any gap (even cwnd).
12986 			 * Close  down the measurement window.
12987 			 */
12988 			if (rack_cwnd_block_ends_measure &&
12989 			    ((app_limited == CTF_JR_CWND_LIMITED) ||
12990 			     (app_limited == CTF_JR_PRR))) {
12991 				/*
12992 				 * The reason we are not sending is
12993 				 * the cwnd (or prr). We have been configured
12994 				 * to end the measurement window in
12995 				 * this case.
12996 				 */
12997 				end_window = 1;
12998 			} else if (app_limited == CTF_JR_PERSISTS) {
12999 				/*
13000 				 * We never end the measurement window
13001 				 * in persists, though in theory we
13002 				 * should be only entering after everything
13003 				 * is acknowledged (so we will probably
13004 				 * never come here).
13005 				 */
13006 				end_window = 0;
13007 			} else if (rack_rwnd_block_ends_measure &&
13008 				   (app_limited == CTF_JR_RWND_LIMITED)) {
13009 				/*
13010 				 * We are rwnd limited and have been
13011 				 * configured to end the measurement
13012 				 * window in this case.
13013 				 */
13014 				end_window = 1;
13015 			} else if (app_limited == CTF_JR_APP_LIMITED) {
13016 				/*
13017 				 * A true application limited period, we have
13018 				 * ran out of data.
13019 				 */
13020 				end_window = 1;
13021 			} else if (app_limited == CTF_JR_ASSESSING) {
13022 				/*
13023 				 * In the assessing case we hit the end of
13024 				 * the if/else and had no known reason
13025 				 * This will panic us under invariants..
13026 				 *
13027 				 * If we get this out in logs we need to
13028 				 * investagate which reason we missed.
13029 				 */
13030 				end_window = 1;
13031 			}
13032 			if (end_window) {
13033 				uint8_t log = 0;
13034 
13035 				if ((tp->t_flags & TF_GPUTINPROG) &&
13036 				    SEQ_GT(tp->gput_ack, tp->snd_max)) {
13037 					/* Mark the last packet has app limited */
13038 					tp->gput_ack = tp->snd_max;
13039 					log = 1;
13040 				}
13041 				rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
13042 				if (rsm && ((rsm->r_flags & RACK_APP_LIMITED) == 0)) {
13043 					if (rack->r_ctl.rc_app_limited_cnt == 0)
13044 						rack->r_ctl.rc_end_appl = rack->r_ctl.rc_first_appl = rsm;
13045 					else {
13046 						/*
13047 						 * Go out to the end app limited and mark
13048 						 * this new one as next and move the end_appl up
13049 						 * to this guy.
13050 						 */
13051 						if (rack->r_ctl.rc_end_appl)
13052 							rack->r_ctl.rc_end_appl->r_nseq_appl = rsm->r_start;
13053 						rack->r_ctl.rc_end_appl = rsm;
13054 					}
13055 					rsm->r_flags |= RACK_APP_LIMITED;
13056 					rack->r_ctl.rc_app_limited_cnt++;
13057 				}
13058 				if (log)
13059 					rack_log_pacing_delay_calc(rack,
13060 								   rack->r_ctl.rc_app_limited_cnt, seq,
13061 								   tp->gput_ack, 0, 0, 4, __LINE__, NULL);
13062 			}
13063 		}
13064 		if (slot) {
13065 			/* set the rack tcb into the slot N */
13066 			counter_u64_add(rack_paced_segments, 1);
13067 		} else if (tot_len_this_send) {
13068 			counter_u64_add(rack_unpaced_segments, 1);
13069 		}
13070 		/* Check if we need to go into persists or not */
13071 		if ((rack->rc_in_persist == 0) &&
13072 		    (tp->snd_max == tp->snd_una) &&
13073 		    TCPS_HAVEESTABLISHED(tp->t_state) &&
13074 		    sbavail(sb) &&
13075 		    (sbavail(sb) > tp->snd_wnd) &&
13076 		    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), minseg))) {
13077 			/* Yes lets make sure to move to persist before timer-start */
13078 			rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
13079 		}
13080 		rack_start_hpts_timer(rack, tp, cts, slot, tot_len_this_send, sup_rack);
13081 		rack_log_type_just_return(rack, cts, tot_len_this_send, slot, hpts_calling, app_limited, cwnd_to_use);
13082 	}
13083 #ifdef NETFLIX_SHARED_CWND
13084 	if ((sbavail(sb) == 0) &&
13085 	    rack->r_ctl.rc_scw) {
13086 		tcp_shared_cwnd_idle(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
13087 		rack->rack_scwnd_is_idle = 1;
13088 	}
13089 #endif
13090 	return (0);
13091 
13092 send:
13093 	if ((flags & TH_FIN) &&
13094 	    sbavail(sb)) {
13095 		/*
13096 		 * We do not transmit a FIN
13097 		 * with data outstanding. We
13098 		 * need to make it so all data
13099 		 * is acked first.
13100 		 */
13101 		flags &= ~TH_FIN;
13102 	}
13103 	/* Enforce stack imposed max seg size if we have one */
13104 	if (rack->r_ctl.rc_pace_max_segs &&
13105 	    (len > rack->r_ctl.rc_pace_max_segs)) {
13106 		mark = 1;
13107 		len = rack->r_ctl.rc_pace_max_segs;
13108 	}
13109 	SOCKBUF_LOCK_ASSERT(sb);
13110 	if (len > 0) {
13111 		if (len >= segsiz)
13112 			tp->t_flags2 |= TF2_PLPMTU_MAXSEGSNT;
13113 		else
13114 			tp->t_flags2 &= ~TF2_PLPMTU_MAXSEGSNT;
13115 	}
13116 	/*
13117 	 * Before ESTABLISHED, force sending of initial options unless TCP
13118 	 * set not to do any options. NOTE: we assume that the IP/TCP header
13119 	 * plus TCP options always fit in a single mbuf, leaving room for a
13120 	 * maximum link header, i.e. max_linkhdr + sizeof (struct tcpiphdr)
13121 	 * + optlen <= MCLBYTES
13122 	 */
13123 	optlen = 0;
13124 #ifdef INET6
13125 	if (isipv6)
13126 		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
13127 	else
13128 #endif
13129 		hdrlen = sizeof(struct tcpiphdr);
13130 
13131 	/*
13132 	 * Compute options for segment. We only have to care about SYN and
13133 	 * established connection segments.  Options for SYN-ACK segments
13134 	 * are handled in TCP syncache.
13135 	 */
13136 	to.to_flags = 0;
13137 	if ((tp->t_flags & TF_NOOPT) == 0) {
13138 		/* Maximum segment size. */
13139 		if (flags & TH_SYN) {
13140 			tp->snd_nxt = tp->iss;
13141 			to.to_mss = tcp_mssopt(&inp->inp_inc);
13142 #ifdef NETFLIX_TCPOUDP
13143 			if (tp->t_port)
13144 				to.to_mss -= V_tcp_udp_tunneling_overhead;
13145 #endif
13146 			to.to_flags |= TOF_MSS;
13147 
13148 			/*
13149 			 * On SYN or SYN|ACK transmits on TFO connections,
13150 			 * only include the TFO option if it is not a
13151 			 * retransmit, as the presence of the TFO option may
13152 			 * have caused the original SYN or SYN|ACK to have
13153 			 * been dropped by a middlebox.
13154 			 */
13155 			if (IS_FASTOPEN(tp->t_flags) &&
13156 			    (tp->t_rxtshift == 0)) {
13157 				if (tp->t_state == TCPS_SYN_RECEIVED) {
13158 					to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
13159 					to.to_tfo_cookie =
13160 						(u_int8_t *)&tp->t_tfo_cookie.server;
13161 					to.to_flags |= TOF_FASTOPEN;
13162 					wanted_cookie = 1;
13163 				} else if (tp->t_state == TCPS_SYN_SENT) {
13164 					to.to_tfo_len =
13165 						tp->t_tfo_client_cookie_len;
13166 					to.to_tfo_cookie =
13167 						tp->t_tfo_cookie.client;
13168 					to.to_flags |= TOF_FASTOPEN;
13169 					wanted_cookie = 1;
13170 					/*
13171 					 * If we wind up having more data to
13172 					 * send with the SYN than can fit in
13173 					 * one segment, don't send any more
13174 					 * until the SYN|ACK comes back from
13175 					 * the other end.
13176 					 */
13177 					sendalot = 0;
13178 				}
13179 			}
13180 		}
13181 		/* Window scaling. */
13182 		if ((flags & TH_SYN) && (tp->t_flags & TF_REQ_SCALE)) {
13183 			to.to_wscale = tp->request_r_scale;
13184 			to.to_flags |= TOF_SCALE;
13185 		}
13186 		/* Timestamps. */
13187 		if ((tp->t_flags & TF_RCVD_TSTMP) ||
13188 		    ((flags & TH_SYN) && (tp->t_flags & TF_REQ_TSTMP))) {
13189 			to.to_tsval = cts + tp->ts_offset;
13190 			to.to_tsecr = tp->ts_recent;
13191 			to.to_flags |= TOF_TS;
13192 		}
13193 		/* Set receive buffer autosizing timestamp. */
13194 		if (tp->rfbuf_ts == 0 &&
13195 		    (so->so_rcv.sb_flags & SB_AUTOSIZE))
13196 			tp->rfbuf_ts = tcp_ts_getticks();
13197 		/* Selective ACK's. */
13198 		if (flags & TH_SYN)
13199 			to.to_flags |= TOF_SACKPERM;
13200 		else if (TCPS_HAVEESTABLISHED(tp->t_state) &&
13201 			 tp->rcv_numsacks > 0) {
13202 			to.to_flags |= TOF_SACK;
13203 			to.to_nsacks = tp->rcv_numsacks;
13204 			to.to_sacks = (u_char *)tp->sackblks;
13205 		}
13206 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
13207 		/* TCP-MD5 (RFC2385). */
13208 		if (tp->t_flags & TF_SIGNATURE)
13209 			to.to_flags |= TOF_SIGNATURE;
13210 #endif				/* TCP_SIGNATURE */
13211 
13212 		/* Processing the options. */
13213 		hdrlen += optlen = tcp_addoptions(&to, opt);
13214 		/*
13215 		 * If we wanted a TFO option to be added, but it was unable
13216 		 * to fit, ensure no data is sent.
13217 		 */
13218 		if (IS_FASTOPEN(tp->t_flags) && wanted_cookie &&
13219 		    !(to.to_flags & TOF_FASTOPEN))
13220 			len = 0;
13221 	}
13222 #ifdef NETFLIX_TCPOUDP
13223 	if (tp->t_port) {
13224 		if (V_tcp_udp_tunneling_port == 0) {
13225 			/* The port was removed?? */
13226 			SOCKBUF_UNLOCK(&so->so_snd);
13227 			return (EHOSTUNREACH);
13228 		}
13229 		hdrlen += sizeof(struct udphdr);
13230 	}
13231 #endif
13232 #ifdef INET6
13233 	if (isipv6)
13234 		ipoptlen = ip6_optlen(tp->t_inpcb);
13235 	else
13236 #endif
13237 		if (tp->t_inpcb->inp_options)
13238 			ipoptlen = tp->t_inpcb->inp_options->m_len -
13239 				offsetof(struct ipoption, ipopt_list);
13240 		else
13241 			ipoptlen = 0;
13242 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
13243 	ipoptlen += ipsec_optlen;
13244 #endif
13245 
13246 #ifdef KERN_TLS
13247  	/* force TSO for so TLS offload can get mss */
13248  	if (sb->sb_flags & SB_TLS_IFNET) {
13249  		force_tso = 1;
13250  	}
13251 #endif
13252 	/*
13253 	 * Adjust data length if insertion of options will bump the packet
13254 	 * length beyond the t_maxseg length. Clear the FIN bit because we
13255 	 * cut off the tail of the segment.
13256 	 */
13257 	if (len + optlen + ipoptlen > tp->t_maxseg) {
13258 		if (tso) {
13259 			uint32_t if_hw_tsomax;
13260 			uint32_t moff;
13261 			int32_t max_len;
13262 
13263 			/* extract TSO information */
13264 			if_hw_tsomax = tp->t_tsomax;
13265 			if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
13266 			if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
13267 			KASSERT(ipoptlen == 0,
13268 				("%s: TSO can't do IP options", __func__));
13269 
13270 			/*
13271 			 * Check if we should limit by maximum payload
13272 			 * length:
13273 			 */
13274 			if (if_hw_tsomax != 0) {
13275 				/* compute maximum TSO length */
13276 				max_len = (if_hw_tsomax - hdrlen -
13277 					   max_linkhdr);
13278 				if (max_len <= 0) {
13279 					len = 0;
13280 				} else if (len > max_len) {
13281 					sendalot = 1;
13282 					len = max_len;
13283 					mark = 2;
13284 				}
13285 			}
13286 			/*
13287 			 * Prevent the last segment from being fractional
13288 			 * unless the send sockbuf can be emptied:
13289 			 */
13290 			max_len = (tp->t_maxseg - optlen);
13291 			if (((sb_offset + len) < sbavail(sb)) &&
13292 			    (hw_tls == 0)) {
13293 				moff = len % (u_int)max_len;
13294 				if (moff != 0) {
13295 					mark = 3;
13296 					len -= moff;
13297 				}
13298 			}
13299                         /*
13300 			 * In case there are too many small fragments don't
13301 			 * use TSO:
13302 			 */
13303 			if (len <= segsiz) {
13304 				mark = 4;
13305 				tso = 0;
13306 			}
13307 			/*
13308 			 * Send the FIN in a separate segment after the bulk
13309 			 * sending is done. We don't trust the TSO
13310 			 * implementations to clear the FIN flag on all but
13311 			 * the last segment.
13312 			 */
13313 			if (tp->t_flags & TF_NEEDFIN) {
13314 				sendalot = 4;
13315 			}
13316 		} else {
13317 			mark = 5;
13318 			if (optlen + ipoptlen >= tp->t_maxseg) {
13319 				/*
13320 				 * Since we don't have enough space to put
13321 				 * the IP header chain and the TCP header in
13322 				 * one packet as required by RFC 7112, don't
13323 				 * send it. Also ensure that at least one
13324 				 * byte of the payload can be put into the
13325 				 * TCP segment.
13326 				 */
13327 				SOCKBUF_UNLOCK(&so->so_snd);
13328 				error = EMSGSIZE;
13329 				sack_rxmit = 0;
13330 				goto out;
13331 			}
13332 			len = tp->t_maxseg - optlen - ipoptlen;
13333 			sendalot = 5;
13334 		}
13335 	} else {
13336 		tso = 0;
13337 		mark = 6;
13338 	}
13339 	KASSERT(len + hdrlen + ipoptlen <= IP_MAXPACKET,
13340 		("%s: len > IP_MAXPACKET", __func__));
13341 #ifdef DIAGNOSTIC
13342 #ifdef INET6
13343 	if (max_linkhdr + hdrlen > MCLBYTES)
13344 #else
13345 		if (max_linkhdr + hdrlen > MHLEN)
13346 #endif
13347 			panic("tcphdr too big");
13348 #endif
13349 
13350 	/*
13351 	 * This KASSERT is here to catch edge cases at a well defined place.
13352 	 * Before, those had triggered (random) panic conditions further
13353 	 * down.
13354 	 */
13355 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
13356 	if ((len == 0) &&
13357 	    (flags & TH_FIN) &&
13358 	    (sbused(sb))) {
13359 		/*
13360 		 * We have outstanding data, don't send a fin by itself!.
13361 		 */
13362 		goto just_return;
13363 	}
13364 	/*
13365 	 * Grab a header mbuf, attaching a copy of data to be transmitted,
13366 	 * and initialize the header from the template for sends on this
13367 	 * connection.
13368 	 */
13369 	if (len) {
13370 		uint32_t max_val;
13371 		uint32_t moff;
13372 
13373 		if (rack->r_ctl.rc_pace_max_segs)
13374 			max_val = rack->r_ctl.rc_pace_max_segs;
13375 		else if (rack->rc_user_set_max_segs)
13376 			max_val = rack->rc_user_set_max_segs * segsiz;
13377 		else
13378 			max_val = len;
13379 		/*
13380 		 * We allow a limit on sending with hptsi.
13381 		 */
13382 		if (len > max_val) {
13383 			mark = 7;
13384 			len = max_val;
13385 		}
13386 #ifdef INET6
13387 		if (MHLEN < hdrlen + max_linkhdr)
13388 			m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
13389 		else
13390 #endif
13391 			m = m_gethdr(M_NOWAIT, MT_DATA);
13392 
13393 		if (m == NULL) {
13394 			SOCKBUF_UNLOCK(sb);
13395 			error = ENOBUFS;
13396 			sack_rxmit = 0;
13397 			goto out;
13398 		}
13399 		m->m_data += max_linkhdr;
13400 		m->m_len = hdrlen;
13401 
13402 		/*
13403 		 * Start the m_copy functions from the closest mbuf to the
13404 		 * sb_offset in the socket buffer chain.
13405 		 */
13406 		mb = sbsndptr_noadv(sb, sb_offset, &moff);
13407 		if (len <= MHLEN - hdrlen - max_linkhdr && !hw_tls) {
13408 			m_copydata(mb, moff, (int)len,
13409 				   mtod(m, caddr_t)+hdrlen);
13410 			if (SEQ_LT(tp->snd_nxt, tp->snd_max))
13411 				sbsndptr_adv(sb, mb, len);
13412 			m->m_len += len;
13413 		} else {
13414 			struct sockbuf *msb;
13415 
13416 			if (SEQ_LT(tp->snd_nxt, tp->snd_max))
13417 				msb = NULL;
13418 			else
13419 				msb = sb;
13420 			m->m_next = tcp_m_copym(
13421 				mb, moff, &len,
13422 				if_hw_tsomaxsegcount, if_hw_tsomaxsegsize, msb,
13423 				((rsm == NULL) ? hw_tls : 0)
13424 #ifdef NETFLIX_COPY_ARGS
13425 				, &filled_all
13426 #endif
13427 				);
13428 			if (len <= (tp->t_maxseg - optlen)) {
13429 				/*
13430 				 * Must have ran out of mbufs for the copy
13431 				 * shorten it to no longer need tso. Lets
13432 				 * not put on sendalot since we are low on
13433 				 * mbufs.
13434 				 */
13435 				tso = 0;
13436 			}
13437 			if (m->m_next == NULL) {
13438 				SOCKBUF_UNLOCK(sb);
13439 				(void)m_free(m);
13440 				error = ENOBUFS;
13441 				sack_rxmit = 0;
13442 				goto out;
13443 			}
13444 		}
13445 		if (SEQ_LT(tp->snd_nxt, tp->snd_max) || sack_rxmit) {
13446 			if (rsm && (rsm->r_flags & RACK_TLP)) {
13447 				/*
13448 				 * TLP should not count in retran count, but
13449 				 * in its own bin
13450 				 */
13451 				counter_u64_add(rack_tlp_retran, 1);
13452 				counter_u64_add(rack_tlp_retran_bytes, len);
13453 			} else {
13454 				tp->t_sndrexmitpack++;
13455 				KMOD_TCPSTAT_INC(tcps_sndrexmitpack);
13456 				KMOD_TCPSTAT_ADD(tcps_sndrexmitbyte, len);
13457 			}
13458 #ifdef STATS
13459 			stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RETXPB,
13460 						 len);
13461 #endif
13462 		} else {
13463 			KMOD_TCPSTAT_INC(tcps_sndpack);
13464 			KMOD_TCPSTAT_ADD(tcps_sndbyte, len);
13465 #ifdef STATS
13466 			stats_voi_update_abs_u64(tp->t_stats, VOI_TCP_TXPB,
13467 						 len);
13468 #endif
13469 		}
13470 		/*
13471 		 * If we're sending everything we've got, set PUSH. (This
13472 		 * will keep happy those implementations which only give
13473 		 * data to the user when a buffer fills or a PUSH comes in.)
13474 		 */
13475 		if (sb_offset + len == sbused(sb) &&
13476 		    sbused(sb) &&
13477 		    !(flags & TH_SYN))
13478 			flags |= TH_PUSH;
13479 
13480 		SOCKBUF_UNLOCK(sb);
13481 	} else {
13482 		SOCKBUF_UNLOCK(sb);
13483 		if (tp->t_flags & TF_ACKNOW)
13484 			KMOD_TCPSTAT_INC(tcps_sndacks);
13485 		else if (flags & (TH_SYN | TH_FIN | TH_RST))
13486 			KMOD_TCPSTAT_INC(tcps_sndctrl);
13487 		else
13488 			KMOD_TCPSTAT_INC(tcps_sndwinup);
13489 
13490 		m = m_gethdr(M_NOWAIT, MT_DATA);
13491 		if (m == NULL) {
13492 			error = ENOBUFS;
13493 			sack_rxmit = 0;
13494 			goto out;
13495 		}
13496 #ifdef INET6
13497 		if (isipv6 && (MHLEN < hdrlen + max_linkhdr) &&
13498 		    MHLEN >= hdrlen) {
13499 			M_ALIGN(m, hdrlen);
13500 		} else
13501 #endif
13502 			m->m_data += max_linkhdr;
13503 		m->m_len = hdrlen;
13504 	}
13505 	SOCKBUF_UNLOCK_ASSERT(sb);
13506 	m->m_pkthdr.rcvif = (struct ifnet *)0;
13507 #ifdef MAC
13508 	mac_inpcb_create_mbuf(inp, m);
13509 #endif
13510 #ifdef INET6
13511 	if (isipv6) {
13512 		ip6 = mtod(m, struct ip6_hdr *);
13513 #ifdef NETFLIX_TCPOUDP
13514 		if (tp->t_port) {
13515 			udp = (struct udphdr *)((caddr_t)ip6 + ipoptlen + sizeof(struct ip6_hdr));
13516 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
13517 			udp->uh_dport = tp->t_port;
13518 			ulen = hdrlen + len - sizeof(struct ip6_hdr);
13519 			udp->uh_ulen = htons(ulen);
13520 			th = (struct tcphdr *)(udp + 1);
13521 		} else
13522 #endif
13523 			th = (struct tcphdr *)(ip6 + 1);
13524 		tcpip_fillheaders(inp,
13525 #ifdef NETFLIX_TCPOUDP
13526 				  tp->t_port,
13527 #endif
13528 				  ip6, th);
13529 	} else
13530 #endif				/* INET6 */
13531 	{
13532 		ip = mtod(m, struct ip *);
13533 #ifdef TCPDEBUG
13534 		ipov = (struct ipovly *)ip;
13535 #endif
13536 #ifdef NETFLIX_TCPOUDP
13537 		if (tp->t_port) {
13538 			udp = (struct udphdr *)((caddr_t)ip + ipoptlen + sizeof(struct ip));
13539 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
13540 			udp->uh_dport = tp->t_port;
13541 			ulen = hdrlen + len - sizeof(struct ip);
13542 			udp->uh_ulen = htons(ulen);
13543 			th = (struct tcphdr *)(udp + 1);
13544 		} else
13545 #endif
13546 			th = (struct tcphdr *)(ip + 1);
13547 		tcpip_fillheaders(inp,
13548 #ifdef NETFLIX_TCPOUDP
13549 				  tp->t_port,
13550 #endif
13551 				  ip, th);
13552 	}
13553 	/*
13554 	 * Fill in fields, remembering maximum advertised window for use in
13555 	 * delaying messages about window sizes. If resending a FIN, be sure
13556 	 * not to use a new sequence number.
13557 	 */
13558 	if (flags & TH_FIN && tp->t_flags & TF_SENTFIN &&
13559 	    tp->snd_nxt == tp->snd_max)
13560 		tp->snd_nxt--;
13561 	/*
13562 	 * If we are starting a connection, send ECN setup SYN packet. If we
13563 	 * are on a retransmit, we may resend those bits a number of times
13564 	 * as per RFC 3168.
13565 	 */
13566 	if (tp->t_state == TCPS_SYN_SENT && V_tcp_do_ecn == 1) {
13567 		if (tp->t_rxtshift >= 1) {
13568 			if (tp->t_rxtshift <= V_tcp_ecn_maxretries)
13569 				flags |= TH_ECE | TH_CWR;
13570 		} else
13571 			flags |= TH_ECE | TH_CWR;
13572 	}
13573 	/* Handle parallel SYN for ECN */
13574 	if ((tp->t_state == TCPS_SYN_RECEIVED) &&
13575 	    (tp->t_flags2 & TF2_ECN_SND_ECE)) {
13576 		flags |= TH_ECE;
13577 		tp->t_flags2 &= ~TF2_ECN_SND_ECE;
13578 	}
13579 	if (tp->t_state == TCPS_ESTABLISHED &&
13580 	    (tp->t_flags2 & TF2_ECN_PERMIT)) {
13581 		/*
13582 		 * If the peer has ECN, mark data packets with ECN capable
13583 		 * transmission (ECT). Ignore pure ack packets,
13584 		 * retransmissions.
13585 		 */
13586 		if (len > 0 && SEQ_GEQ(tp->snd_nxt, tp->snd_max) &&
13587 		    (sack_rxmit == 0)) {
13588 #ifdef INET6
13589 			if (isipv6)
13590 				ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20);
13591 			else
13592 #endif
13593 				ip->ip_tos |= IPTOS_ECN_ECT0;
13594 			KMOD_TCPSTAT_INC(tcps_ecn_ect0);
13595 			/*
13596 			 * Reply with proper ECN notifications.
13597 			 * Only set CWR on new data segments.
13598 			 */
13599 			if (tp->t_flags2 & TF2_ECN_SND_CWR) {
13600 				flags |= TH_CWR;
13601 				tp->t_flags2 &= ~TF2_ECN_SND_CWR;
13602 			}
13603 		}
13604 		if (tp->t_flags2 & TF2_ECN_SND_ECE)
13605 			flags |= TH_ECE;
13606 	}
13607 	/*
13608 	 * If we are doing retransmissions, then snd_nxt will not reflect
13609 	 * the first unsent octet.  For ACK only packets, we do not want the
13610 	 * sequence number of the retransmitted packet, we want the sequence
13611 	 * number of the next unsent octet.  So, if there is no data (and no
13612 	 * SYN or FIN), use snd_max instead of snd_nxt when filling in
13613 	 * ti_seq.  But if we are in persist state, snd_max might reflect
13614 	 * one byte beyond the right edge of the window, so use snd_nxt in
13615 	 * that case, since we know we aren't doing a retransmission.
13616 	 * (retransmit and persist are mutually exclusive...)
13617 	 */
13618 	if (sack_rxmit == 0) {
13619 		if (len || (flags & (TH_SYN | TH_FIN)) ||
13620 		    rack->rc_in_persist) {
13621 			th->th_seq = htonl(tp->snd_nxt);
13622 			rack_seq = tp->snd_nxt;
13623 		} else if (flags & TH_RST) {
13624 			/*
13625 			 * For a Reset send the last cum ack in sequence
13626 			 * (this like any other choice may still generate a
13627 			 * challenge ack, if a ack-update packet is in
13628 			 * flight).
13629 			 */
13630 			th->th_seq = htonl(tp->snd_una);
13631 			rack_seq = tp->snd_una;
13632 		} else {
13633 			th->th_seq = htonl(tp->snd_max);
13634 			rack_seq = tp->snd_max;
13635 		}
13636 	} else {
13637 		th->th_seq = htonl(rsm->r_start);
13638 		rack_seq = rsm->r_start;
13639 	}
13640 	th->th_ack = htonl(tp->rcv_nxt);
13641 	if (optlen) {
13642 		bcopy(opt, th + 1, optlen);
13643 		th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
13644 	}
13645 	th->th_flags = flags;
13646 	/*
13647 	 * Calculate receive window.  Don't shrink window, but avoid silly
13648 	 * window syndrome.
13649 	 * If a RST segment is sent, advertise a window of zero.
13650 	 */
13651 	if (flags & TH_RST) {
13652 		recwin = 0;
13653 	} else {
13654 		if (recwin < (long)(so->so_rcv.sb_hiwat / 4) &&
13655 		    recwin < (long)segsiz)
13656 			recwin = 0;
13657 		if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt) &&
13658 		    recwin < (long)(tp->rcv_adv - tp->rcv_nxt))
13659 			recwin = (long)(tp->rcv_adv - tp->rcv_nxt);
13660 	}
13661 
13662 	/*
13663 	 * According to RFC1323 the window field in a SYN (i.e., a <SYN> or
13664 	 * <SYN,ACK>) segment itself is never scaled.  The <SYN,ACK> case is
13665 	 * handled in syncache.
13666 	 */
13667 	if (flags & TH_SYN)
13668 		th->th_win = htons((u_short)
13669 				   (min(sbspace(&so->so_rcv), TCP_MAXWIN)));
13670 	else {
13671 		/* Avoid shrinking window with window scaling. */
13672 		recwin = roundup2(recwin, 1 << tp->rcv_scale);
13673 		th->th_win = htons((u_short)(recwin >> tp->rcv_scale));
13674 	}
13675 	/*
13676 	 * Adjust the RXWIN0SENT flag - indicate that we have advertised a 0
13677 	 * window.  This may cause the remote transmitter to stall.  This
13678 	 * flag tells soreceive() to disable delayed acknowledgements when
13679 	 * draining the buffer.  This can occur if the receiver is
13680 	 * attempting to read more data than can be buffered prior to
13681 	 * transmitting on the connection.
13682 	 */
13683 	if (th->th_win == 0) {
13684 		tp->t_sndzerowin++;
13685 		tp->t_flags |= TF_RXWIN0SENT;
13686 	} else
13687 		tp->t_flags &= ~TF_RXWIN0SENT;
13688 	tp->snd_up = tp->snd_una;	/* drag it along, its deprecated  */
13689 
13690 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
13691 	if (to.to_flags & TOF_SIGNATURE) {
13692 		/*
13693 		 * Calculate MD5 signature and put it into the place
13694 		 * determined before.
13695 		 * NOTE: since TCP options buffer doesn't point into
13696 		 * mbuf's data, calculate offset and use it.
13697 		 */
13698 		if (!TCPMD5_ENABLED() || TCPMD5_OUTPUT(m, th,
13699 						       (u_char *)(th + 1) + (to.to_signature - opt)) != 0) {
13700 			/*
13701 			 * Do not send segment if the calculation of MD5
13702 			 * digest has failed.
13703 			 */
13704 			goto out;
13705 		}
13706 	}
13707 #endif
13708 
13709 	/*
13710 	 * Put TCP length in extended header, and then checksum extended
13711 	 * header and data.
13712 	 */
13713 	m->m_pkthdr.len = hdrlen + len;	/* in6_cksum() need this */
13714 #ifdef INET6
13715 	if (isipv6) {
13716 		/*
13717 		 * ip6_plen is not need to be filled now, and will be filled
13718 		 * in ip6_output.
13719 		 */
13720 		if (tp->t_port) {
13721 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
13722 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
13723 			udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
13724 			th->th_sum = htons(0);
13725 			UDPSTAT_INC(udps_opackets);
13726 		} else {
13727 			m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
13728 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
13729 			th->th_sum = in6_cksum_pseudo(ip6,
13730 						      sizeof(struct tcphdr) + optlen + len, IPPROTO_TCP,
13731 						      0);
13732 		}
13733 	}
13734 #endif
13735 #if defined(INET6) && defined(INET)
13736 	else
13737 #endif
13738 #ifdef INET
13739 	{
13740 		if (tp->t_port) {
13741 			m->m_pkthdr.csum_flags = CSUM_UDP;
13742 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
13743 			udp->uh_sum = in_pseudo(ip->ip_src.s_addr,
13744 						ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP));
13745 			th->th_sum = htons(0);
13746 			UDPSTAT_INC(udps_opackets);
13747 		} else {
13748 			m->m_pkthdr.csum_flags = CSUM_TCP;
13749 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
13750 			th->th_sum = in_pseudo(ip->ip_src.s_addr,
13751 					       ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) +
13752 									IPPROTO_TCP + len + optlen));
13753 		}
13754 		/* IP version must be set here for ipv4/ipv6 checking later */
13755 		KASSERT(ip->ip_v == IPVERSION,
13756 			("%s: IP version incorrect: %d", __func__, ip->ip_v));
13757 	}
13758 #endif
13759 	/*
13760 	 * Enable TSO and specify the size of the segments. The TCP pseudo
13761 	 * header checksum is always provided. XXX: Fixme: This is currently
13762 	 * not the case for IPv6.
13763 	 */
13764 	if (tso || force_tso) {
13765 		KASSERT(force_tso || len > tp->t_maxseg - optlen,
13766 			("%s: len <= tso_segsz", __func__));
13767 		m->m_pkthdr.csum_flags |= CSUM_TSO;
13768 		m->m_pkthdr.tso_segsz = tp->t_maxseg - optlen;
13769 	}
13770 	KASSERT(len + hdrlen == m_length(m, NULL),
13771 		("%s: mbuf chain different than expected: %d + %u != %u",
13772 		 __func__, len, hdrlen, m_length(m, NULL)));
13773 
13774 #ifdef TCP_HHOOK
13775 	/* Run HHOOK_TCP_ESTABLISHED_OUT helper hooks. */
13776 	hhook_run_tcp_est_out(tp, th, &to, len, tso);
13777 #endif
13778 #ifdef TCPDEBUG
13779 	/*
13780 	 * Trace.
13781 	 */
13782 	if (so->so_options & SO_DEBUG) {
13783 		u_short save = 0;
13784 
13785 #ifdef INET6
13786 		if (!isipv6)
13787 #endif
13788 		{
13789 			save = ipov->ih_len;
13790 			ipov->ih_len = htons(m->m_pkthdr.len	/* - hdrlen +
13791 								 * (th->th_off << 2) */ );
13792 		}
13793 		tcp_trace(TA_OUTPUT, tp->t_state, tp, mtod(m, void *), th, 0);
13794 #ifdef INET6
13795 		if (!isipv6)
13796 #endif
13797 			ipov->ih_len = save;
13798 	}
13799 #endif				/* TCPDEBUG */
13800 
13801 	/* We're getting ready to send; log now. */
13802 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
13803 		union tcp_log_stackspecific log;
13804 		struct timeval tv;
13805 
13806 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
13807 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
13808 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
13809 		if (rack->rack_no_prr)
13810 			log.u_bbr.flex1 = 0;
13811 		else
13812 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
13813 		log.u_bbr.flex2 = rack->r_ctl.rc_pace_min_segs;
13814 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
13815 		log.u_bbr.flex4 = orig_len;
13816 		if (filled_all)
13817 			log.u_bbr.flex5 = 0x80000000;
13818 		else
13819 			log.u_bbr.flex5 = 0;
13820 		/* Save off the early/late values */
13821 		log.u_bbr.flex6 = rack->r_ctl.rc_agg_early;
13822 		log.u_bbr.applimited = rack->r_ctl.rc_agg_delayed;
13823 		log.u_bbr.bw_inuse = rack_get_bw(rack);
13824 		if (rsm || sack_rxmit) {
13825 			if (doing_tlp)
13826 				log.u_bbr.flex8 = 2;
13827 			else
13828 				log.u_bbr.flex8 = 1;
13829 		} else {
13830 			log.u_bbr.flex8 = 0;
13831 		}
13832 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, rsm);
13833 		log.u_bbr.flex7 = mark;
13834 		log.u_bbr.pkts_out = tp->t_maxseg;
13835 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
13836 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
13837 		log.u_bbr.lt_epoch = cwnd_to_use;
13838 		log.u_bbr.delivered = sendalot;
13839 		lgb = tcp_log_event_(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_OUT, ERRNO_UNK,
13840 				     len, &log, false, NULL, NULL, 0, &tv);
13841 	} else
13842 		lgb = NULL;
13843 
13844 	/*
13845 	 * Fill in IP length and desired time to live and send to IP level.
13846 	 * There should be a better way to handle ttl and tos; we could keep
13847 	 * them in the template, but need a way to checksum without them.
13848 	 */
13849 	/*
13850 	 * m->m_pkthdr.len should have been set before cksum calcuration,
13851 	 * because in6_cksum() need it.
13852 	 */
13853 #ifdef INET6
13854 	if (isipv6) {
13855 		/*
13856 		 * we separately set hoplimit for every segment, since the
13857 		 * user might want to change the value via setsockopt. Also,
13858 		 * desired default hop limit might be changed via Neighbor
13859 		 * Discovery.
13860 		 */
13861 		ip6->ip6_hlim = in6_selecthlim(inp, NULL);
13862 
13863 		/*
13864 		 * Set the packet size here for the benefit of DTrace
13865 		 * probes. ip6_output() will set it properly; it's supposed
13866 		 * to include the option header lengths as well.
13867 		 */
13868 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
13869 
13870 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss)
13871 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
13872 		else
13873 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
13874 
13875 		if (tp->t_state == TCPS_SYN_SENT)
13876 			TCP_PROBE5(connect__request, NULL, tp, ip6, tp, th);
13877 
13878 		TCP_PROBE5(send, NULL, tp, ip6, tp, th);
13879 		/* TODO: IPv6 IP6TOS_ECT bit on */
13880 		error = ip6_output(m, inp->in6p_outputopts,
13881 				   &inp->inp_route6,
13882 				   ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0),
13883 				   NULL, NULL, inp);
13884 
13885 		if (error == EMSGSIZE && inp->inp_route6.ro_nh != NULL)
13886 			mtu = inp->inp_route6.ro_nh->nh_mtu;
13887 	}
13888 #endif				/* INET6 */
13889 #if defined(INET) && defined(INET6)
13890 	else
13891 #endif
13892 #ifdef INET
13893 	{
13894 		ip->ip_len = htons(m->m_pkthdr.len);
13895 #ifdef INET6
13896 		if (inp->inp_vflag & INP_IPV6PROTO)
13897 			ip->ip_ttl = in6_selecthlim(inp, NULL);
13898 #endif				/* INET6 */
13899 		/*
13900 		 * If we do path MTU discovery, then we set DF on every
13901 		 * packet. This might not be the best thing to do according
13902 		 * to RFC3390 Section 2. However the tcp hostcache migitates
13903 		 * the problem so it affects only the first tcp connection
13904 		 * with a host.
13905 		 *
13906 		 * NB: Don't set DF on small MTU/MSS to have a safe
13907 		 * fallback.
13908 		 */
13909 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) {
13910 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
13911 			if (tp->t_port == 0 || len < V_tcp_minmss) {
13912 				ip->ip_off |= htons(IP_DF);
13913 			}
13914 		} else {
13915 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
13916 		}
13917 
13918 		if (tp->t_state == TCPS_SYN_SENT)
13919 			TCP_PROBE5(connect__request, NULL, tp, ip, tp, th);
13920 
13921 		TCP_PROBE5(send, NULL, tp, ip, tp, th);
13922 
13923 		error = ip_output(m, inp->inp_options, &inp->inp_route,
13924 				  ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0), 0,
13925 				  inp);
13926 		if (error == EMSGSIZE && inp->inp_route.ro_nh != NULL)
13927 			mtu = inp->inp_route.ro_nh->nh_mtu;
13928 	}
13929 #endif				/* INET */
13930 
13931 out:
13932 	if (lgb) {
13933 		lgb->tlb_errno = error;
13934 		lgb = NULL;
13935 	}
13936 	/*
13937 	 * In transmit state, time the transmission and arrange for the
13938 	 * retransmit.  In persist state, just set snd_max.
13939 	 */
13940 	if (error == 0) {
13941 		rack->forced_ack = 0;	/* If we send something zap the FA flag */
13942 		if (rsm && (doing_tlp == 0)) {
13943 			/* Set we retransmitted */
13944 			rack->rc_gp_saw_rec = 1;
13945 		} else {
13946 			if (cwnd_to_use > tp->snd_ssthresh) {
13947 				/* Set we sent in CA */
13948 				rack->rc_gp_saw_ca = 1;
13949 			} else {
13950 				/* Set we sent in SS */
13951 				rack->rc_gp_saw_ss = 1;
13952 			}
13953 		}
13954 		if (TCPS_HAVEESTABLISHED(tp->t_state) &&
13955 		    (tp->t_flags & TF_SACK_PERMIT) &&
13956 		    tp->rcv_numsacks > 0)
13957 			tcp_clean_dsack_blocks(tp);
13958 		tot_len_this_send += len;
13959 		if (len == 0)
13960 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_SNDACK], 1);
13961 		else if (len == 1) {
13962 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_PERSIST], 1);
13963 		} else if (len > 1) {
13964 			int idx;
13965 
13966 			idx = (len / segsiz) + 3;
13967 			if (idx >= TCP_MSS_ACCT_ATIMER)
13968 				counter_u64_add(rack_out_size[(TCP_MSS_ACCT_ATIMER-1)], 1);
13969 			else
13970 				counter_u64_add(rack_out_size[idx], 1);
13971 		}
13972 		if (hw_tls && len > 0) {
13973 			if (filled_all) {
13974 				counter_u64_add(rack_tls_filled, 1);
13975 				rack_log_type_hrdwtso(tp, rack, len, 0, orig_len, 1);
13976 			} else {
13977 				if (rsm) {
13978 					counter_u64_add(rack_tls_rxt, 1);
13979 					rack_log_type_hrdwtso(tp, rack, len, 2, orig_len, 1);
13980 				} else if (doing_tlp) {
13981 					counter_u64_add(rack_tls_tlp, 1);
13982 					rack_log_type_hrdwtso(tp, rack, len, 3, orig_len, 1);
13983 				} else if ( (ctf_outstanding(tp) + minseg) > sbavail(sb)) {
13984 					counter_u64_add(rack_tls_app, 1);
13985 					rack_log_type_hrdwtso(tp, rack, len, 4, orig_len, 1);
13986 				} else if ((ctf_flight_size(tp, rack->r_ctl.rc_sacked) + minseg) > cwnd_to_use) {
13987 					counter_u64_add(rack_tls_cwnd, 1);
13988 					rack_log_type_hrdwtso(tp, rack, len, 5, orig_len, 1);
13989 				} else if ((ctf_outstanding(tp) + minseg) > tp->snd_wnd) {
13990 					counter_u64_add(rack_tls_rwnd, 1);
13991 					rack_log_type_hrdwtso(tp, rack, len, 6, orig_len, 1);
13992 				} else {
13993 					rack_log_type_hrdwtso(tp, rack, len, 7, orig_len, 1);
13994 					counter_u64_add(rack_tls_other, 1);
13995 				}
13996 			}
13997 		}
13998 	}
13999 	if (rack->rack_no_prr == 0) {
14000 		if (sub_from_prr && (error == 0)) {
14001 			if (rack->r_ctl.rc_prr_sndcnt >= len)
14002 				rack->r_ctl.rc_prr_sndcnt -= len;
14003 			else
14004 				rack->r_ctl.rc_prr_sndcnt = 0;
14005 		}
14006  	}
14007 	sub_from_prr = 0;
14008 	rack_log_output(tp, &to, len, rack_seq, (uint8_t) flags, error, cts,
14009 			pass, rsm, us_cts);
14010 	if ((error == 0) &&
14011 	    (len > 0) &&
14012 	    (tp->snd_una == tp->snd_max))
14013 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
14014 	/* Now are we in persists? */
14015 	if (rack->rc_in_persist == 0) {
14016 		tcp_seq startseq = tp->snd_nxt;
14017 
14018 		/* Track our lost count */
14019 		if (rsm && (doing_tlp == 0))
14020 			rack->r_ctl.rc_loss_count += rsm->r_end - rsm->r_start;
14021 		/*
14022 		 * Advance snd_nxt over sequence space of this segment.
14023 		 */
14024 		if (error)
14025 			/* We don't log or do anything with errors */
14026 			goto nomore;
14027 		if (doing_tlp == 0) {
14028 			if (rsm == NULL) {
14029 				/*
14030 				 * Not a retransmission of some
14031 				 * sort, new data is going out so
14032 				 * clear our TLP count and flag.
14033 				 */
14034 				rack->rc_tlp_in_progress = 0;
14035 				rack->r_ctl.rc_tlp_cnt_out = 0;
14036 			}
14037 		} else {
14038 			/*
14039 			 * We have just sent a TLP, mark that it is true
14040 			 * and make sure our in progress is set so we
14041 			 * continue to check the count.
14042 			 */
14043 			rack->rc_tlp_in_progress = 1;
14044 			rack->r_ctl.rc_tlp_cnt_out++;
14045 		}
14046 		if (flags & (TH_SYN | TH_FIN)) {
14047 			if (flags & TH_SYN)
14048 				tp->snd_nxt++;
14049 			if (flags & TH_FIN) {
14050 				tp->snd_nxt++;
14051 				tp->t_flags |= TF_SENTFIN;
14052 			}
14053 		}
14054 		/* In the ENOBUFS case we do *not* update snd_max */
14055 		if (sack_rxmit)
14056 			goto nomore;
14057 
14058 		tp->snd_nxt += len;
14059 		if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
14060 			if (tp->snd_una == tp->snd_max) {
14061 				/*
14062 				 * Update the time we just added data since
14063 				 * none was outstanding.
14064 				 */
14065 				rack_log_progress_event(rack, tp, ticks, PROGRESS_START, __LINE__);
14066 				tp->t_acktime = ticks;
14067 			}
14068 			tp->snd_max = tp->snd_nxt;
14069 			/*
14070 			 * Time this transmission if not a retransmission and
14071 			 * not currently timing anything.
14072 			 * This is only relevant in case of switching back to
14073 			 * the base stack.
14074 			 */
14075 			if (tp->t_rtttime == 0) {
14076 				tp->t_rtttime = ticks;
14077 				tp->t_rtseq = startseq;
14078 				KMOD_TCPSTAT_INC(tcps_segstimed);
14079 			}
14080 			if (len &&
14081 			    ((tp->t_flags & TF_GPUTINPROG) == 0))
14082 				rack_start_gp_measurement(tp, rack, startseq, sb_offset);
14083 		}
14084 	} else {
14085 		/*
14086 		 * Persist case, update snd_max but since we are in persist
14087 		 * mode (no window) we do not update snd_nxt.
14088 		 */
14089 		int32_t xlen = len;
14090 
14091 		if (error)
14092 			goto nomore;
14093 
14094 		if (flags & TH_SYN)
14095 			++xlen;
14096 		if (flags & TH_FIN) {
14097 			++xlen;
14098 			tp->t_flags |= TF_SENTFIN;
14099 		}
14100 		/* In the ENOBUFS case we do *not* update snd_max */
14101 		if (SEQ_GT(tp->snd_nxt + xlen, tp->snd_max)) {
14102 			if (tp->snd_una == tp->snd_max) {
14103 				/*
14104 				 * Update the time we just added data since
14105 				 * none was outstanding.
14106 				 */
14107 				rack_log_progress_event(rack, tp, ticks, PROGRESS_START, __LINE__);
14108 				tp->t_acktime = ticks;
14109 			}
14110 			tp->snd_max = tp->snd_nxt + len;
14111 		}
14112 	}
14113 nomore:
14114 	if (error) {
14115 		rack->r_ctl.rc_agg_delayed = 0;
14116 		rack->r_early = 0;
14117 		rack->r_late = 0;
14118 		rack->r_ctl.rc_agg_early = 0;
14119 		SOCKBUF_UNLOCK_ASSERT(sb);	/* Check gotos. */
14120 		/*
14121 		 * Failures do not advance the seq counter above. For the
14122 		 * case of ENOBUFS we will fall out and retry in 1ms with
14123 		 * the hpts. Everything else will just have to retransmit
14124 		 * with the timer.
14125 		 *
14126 		 * In any case, we do not want to loop around for another
14127 		 * send without a good reason.
14128 		 */
14129 		sendalot = 0;
14130 		switch (error) {
14131 		case EPERM:
14132 			tp->t_softerror = error;
14133 			return (error);
14134 		case ENOBUFS:
14135 			if (slot == 0) {
14136 				/*
14137 				 * Pace us right away to retry in a some
14138 				 * time
14139 				 */
14140 				slot = ((1 + rack->rc_enobuf) * HPTS_USEC_IN_MSEC);
14141 				if (rack->rc_enobuf < 126)
14142 					rack->rc_enobuf++;
14143 				if (slot > ((rack->rc_rack_rtt / 2) * HPTS_USEC_IN_MSEC)) {
14144 					slot = (rack->rc_rack_rtt / 2) * HPTS_USEC_IN_MSEC;
14145 				}
14146 				if (slot < (10 * HPTS_USEC_IN_MSEC))
14147 					slot = 10 * HPTS_USEC_IN_MSEC;
14148 			}
14149 			counter_u64_add(rack_saw_enobuf, 1);
14150 			error = 0;
14151 			goto enobufs;
14152 		case EMSGSIZE:
14153 			/*
14154 			 * For some reason the interface we used initially
14155 			 * to send segments changed to another or lowered
14156 			 * its MTU. If TSO was active we either got an
14157 			 * interface without TSO capabilits or TSO was
14158 			 * turned off. If we obtained mtu from ip_output()
14159 			 * then update it and try again.
14160 			 */
14161 			if (tso)
14162 				tp->t_flags &= ~TF_TSO;
14163 			if (mtu != 0) {
14164 				tcp_mss_update(tp, -1, mtu, NULL, NULL);
14165 				goto again;
14166 			}
14167 			slot = 10 * HPTS_USEC_IN_MSEC;
14168 			rack_start_hpts_timer(rack, tp, cts, slot, 0, 0);
14169 			return (error);
14170 		case ENETUNREACH:
14171 			counter_u64_add(rack_saw_enetunreach, 1);
14172 		case EHOSTDOWN:
14173 		case EHOSTUNREACH:
14174 		case ENETDOWN:
14175 			if (TCPS_HAVERCVDSYN(tp->t_state)) {
14176 				tp->t_softerror = error;
14177 			}
14178 			/* FALLTHROUGH */
14179 		default:
14180 			slot = 10 * HPTS_USEC_IN_MSEC;
14181 			rack_start_hpts_timer(rack, tp, cts, slot, 0, 0);
14182 			return (error);
14183 		}
14184 	} else {
14185 		rack->rc_enobuf = 0;
14186 	}
14187 	KMOD_TCPSTAT_INC(tcps_sndtotal);
14188 
14189 	/*
14190 	 * Data sent (as far as we can tell). If this advertises a larger
14191 	 * window than any other segment, then remember the size of the
14192 	 * advertised window. Any pending ACK has now been sent.
14193 	 */
14194 	if (recwin > 0 && SEQ_GT(tp->rcv_nxt + recwin, tp->rcv_adv))
14195 		tp->rcv_adv = tp->rcv_nxt + recwin;
14196 	tp->last_ack_sent = tp->rcv_nxt;
14197 	tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
14198 enobufs:
14199 	/* Assure when we leave that snd_nxt will point to top */
14200 	if (SEQ_GT(tp->snd_max, tp->snd_nxt))
14201 		tp->snd_nxt = tp->snd_max;
14202 	if (sendalot) {
14203 		/* Do we need to turn off sendalot? */
14204 		if (rack->r_ctl.rc_pace_max_segs &&
14205 		    (tot_len_this_send >= rack->r_ctl.rc_pace_max_segs)) {
14206 			/* We hit our max. */
14207 			sendalot = 0;
14208 		} else if ((rack->rc_user_set_max_segs) &&
14209 			   (tot_len_this_send >= (rack->rc_user_set_max_segs * segsiz))) {
14210 			/* We hit the user defined max */
14211 			sendalot = 0;
14212 		}
14213 	}
14214 	if ((error == 0) && (flags & TH_FIN))
14215 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_FIN);
14216 	if (flags & TH_RST) {
14217 		/*
14218 		 * We don't send again after sending a RST.
14219 		 */
14220 		slot = 0;
14221 		sendalot = 0;
14222 		if (error == 0)
14223 			tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
14224 	} else if ((slot == 0) && (sendalot == 0) && tot_len_this_send) {
14225 		/*
14226 		 * Get our pacing rate, if an error
14227 		 * occured in sending (ENOBUF) we would
14228 		 * hit the else if with slot preset. Other
14229 		 * errors return.
14230 		 */
14231 		slot = rack_get_pacing_delay(rack, tp, tot_len_this_send, rsm, segsiz);
14232 	}
14233 	if (rsm &&
14234 	    rack->use_rack_rr) {
14235 		/* Its a retransmit and we use the rack cheat? */
14236 		if ((slot == 0) ||
14237 		    (rack->rc_always_pace == 0) ||
14238 		    (rack->r_rr_config == 1)) {
14239 			/*
14240 			 * We have no pacing set or we
14241 			 * are using old-style rack or
14242 			 * we are overriden to use the old 1ms pacing.
14243 			 */
14244 			slot = rack->r_ctl.rc_min_to * HPTS_USEC_IN_MSEC;
14245 		}
14246 	}
14247 	if (slot) {
14248 		/* set the rack tcb into the slot N */
14249 		counter_u64_add(rack_paced_segments, 1);
14250 	} else if (sendalot) {
14251 		if (len)
14252 			counter_u64_add(rack_unpaced_segments, 1);
14253 		sack_rxmit = 0;
14254 		goto again;
14255 	} else if (len) {
14256 		counter_u64_add(rack_unpaced_segments, 1);
14257 	}
14258 	rack_start_hpts_timer(rack, tp, cts, slot, tot_len_this_send, 0);
14259 	return (error);
14260 }
14261 
14262 static void
14263 rack_update_seg(struct tcp_rack *rack)
14264 {
14265 	uint32_t orig_val;
14266 
14267 	orig_val = rack->r_ctl.rc_pace_max_segs;
14268 	rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
14269 	if (orig_val != rack->r_ctl.rc_pace_max_segs)
14270 		rack_log_pacing_delay_calc(rack, 0, 0, orig_val, 0, 0, 15, __LINE__, NULL);
14271 }
14272 
14273 /*
14274  * rack_ctloutput() must drop the inpcb lock before performing copyin on
14275  * socket option arguments.  When it re-acquires the lock after the copy, it
14276  * has to revalidate that the connection is still valid for the socket
14277  * option.
14278  */
14279 static int
14280 rack_set_sockopt(struct socket *so, struct sockopt *sopt,
14281     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack)
14282 {
14283 	struct epoch_tracker et;
14284 	uint64_t val;
14285 	int32_t error = 0, optval;
14286 	uint16_t ca, ss;
14287 
14288 
14289 	switch (sopt->sopt_name) {
14290 	case TCP_RACK_PROP_RATE:		/*  URL:prop_rate */
14291 	case TCP_RACK_PROP	:		/*  URL:prop */
14292 	case TCP_RACK_TLP_REDUCE:		/*  URL:tlp_reduce */
14293 	case TCP_RACK_EARLY_RECOV:		/*  URL:early_recov */
14294 	case TCP_RACK_PACE_REDUCE:		/*  Not used */
14295         /*  Pacing related ones */
14296 	case TCP_RACK_PACE_ALWAYS:		/*  URL:pace_always */
14297 	case TCP_BBR_RACK_INIT_RATE:		/*  URL:irate */
14298 	case TCP_BBR_IWINTSO:			/*  URL:tso_iwin */
14299 	case TCP_RACK_PACE_MAX_SEG:		/*  URL:pace_max_seg */
14300 	case TCP_RACK_FORCE_MSEG:		/*  URL:force_max_seg */
14301 	case TCP_RACK_PACE_RATE_CA:		/*  URL:pr_ca */
14302 	case TCP_RACK_PACE_RATE_SS:		/*  URL:pr_ss*/
14303 	case TCP_RACK_PACE_RATE_REC:		/*  URL:pr_rec */
14304 	case TCP_RACK_GP_INCREASE_CA:		/*  URL:gp_inc_ca */
14305 	case TCP_RACK_GP_INCREASE_SS:		/*  URL:gp_inc_ss */
14306 	case TCP_RACK_GP_INCREASE_REC:		/*  URL:gp_inc_rec */
14307 	case TCP_RACK_RR_CONF:			/*  URL:rrr_conf */
14308 	case TCP_BBR_HDWR_PACE:			/*  URL:hdwrpace */
14309        /* End pacing related */
14310 	case TCP_DELACK:
14311 	case TCP_RACK_PRR_SENDALOT:		/*  URL:prr_sendalot */
14312 	case TCP_RACK_MIN_TO:			/*  URL:min_to */
14313 	case TCP_RACK_EARLY_SEG:		/*  URL:early_seg */
14314 	case TCP_RACK_REORD_THRESH:		/*  URL:reord_thresh */
14315 	case TCP_RACK_REORD_FADE:		/*  URL:reord_fade */
14316 	case TCP_RACK_TLP_THRESH:		/*  URL:tlp_thresh */
14317 	case TCP_RACK_PKT_DELAY:		/*  URL:pkt_delay */
14318 	case TCP_RACK_TLP_USE:			/*  URL:tlp_use */
14319 	case TCP_RACK_TLP_INC_VAR:		/*  URL:tlp_inc_var */
14320 	case TCP_RACK_IDLE_REDUCE_HIGH:		/*  URL:idle_reduce_high */
14321 	case TCP_BBR_RACK_RTT_USE:		/*  URL:rttuse */
14322 	case TCP_BBR_USE_RACK_RR:		/*  URL:rackrr */
14323 	case TCP_RACK_DO_DETECTION:		/*  URL:detect */
14324 	case TCP_NO_PRR:			/*  URL:noprr */
14325 	case TCP_TIMELY_DYN_ADJ:		/*  URL:dynamic */
14326 	case TCP_DATA_AFTER_CLOSE:
14327 	case TCP_RACK_NONRXT_CFG_RATE:		/*  URL:nonrxtcr */
14328 	case TCP_SHARED_CWND_ENABLE:		/*  URL:scwnd */
14329 	case TCP_RACK_MBUF_QUEUE:		/*  URL:mqueue */
14330 	case TCP_RACK_NO_PUSH_AT_MAX:		/*  URL:npush */
14331 	case TCP_RACK_PACE_TO_FILL:		/*  URL:fillcw */
14332 	case TCP_SHARED_CWND_TIME_LIMIT:	/*  URL:lscwnd */
14333 	case TCP_RACK_PROFILE:			/*  URL:profile */
14334 		break;
14335 	default:
14336 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14337 		break;
14338 	}
14339 	INP_WUNLOCK(inp);
14340 	error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
14341 	if (error)
14342 		return (error);
14343 	INP_WLOCK(inp);
14344 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
14345 		INP_WUNLOCK(inp);
14346 		return (ECONNRESET);
14347 	}
14348 	tp = intotcpcb(inp);
14349 	rack = (struct tcp_rack *)tp->t_fb_ptr;
14350 	switch (sopt->sopt_name) {
14351 	case TCP_RACK_PROFILE:
14352 		RACK_OPTS_INC(tcp_profile);
14353 		if (optval == 1) {
14354 			/* pace_always=1 */
14355 			rack->rc_always_pace = 1;
14356 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
14357 			/* scwnd=1 */
14358 			rack->rack_enable_scwnd = 1;
14359 			/* dynamic=100 */
14360 			rack->rc_gp_dyn_mul = 1;
14361 			rack->r_ctl.rack_per_of_gp_ca = 100;
14362 			/* rrr_conf=3 */
14363 			rack->r_rr_config = 3;
14364 			/* npush=2 */
14365 			rack->r_ctl.rc_no_push_at_mrtt = 2;
14366 			/* fillcw=1 */
14367 			rack->rc_pace_to_cwnd = 1;
14368 			rack->rc_pace_fill_if_rttin_range = 0;
14369 			rack->rtt_limit_mul = 0;
14370 			/* noprr=1 */
14371 			rack->rack_no_prr = 1;
14372 			/* lscwnd=1 */
14373 			rack->r_limit_scw = 1;
14374 		} else if (optval == 2) {
14375 			/* pace_always=1 */
14376 			rack->rc_always_pace = 1;
14377 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
14378 			/* scwnd=1 */
14379 			rack->rack_enable_scwnd = 1;
14380 			/* dynamic=100 */
14381 			rack->rc_gp_dyn_mul = 1;
14382 			rack->r_ctl.rack_per_of_gp_ca = 100;
14383 			/* rrr_conf=3 */
14384 			rack->r_rr_config = 3;
14385 			/* npush=2 */
14386 			rack->r_ctl.rc_no_push_at_mrtt = 2;
14387 			/* fillcw=1 */
14388 			rack->rc_pace_to_cwnd = 1;
14389 			rack->rc_pace_fill_if_rttin_range = 0;
14390 			rack->rtt_limit_mul = 0;
14391 			/* noprr=1 */
14392 			rack->rack_no_prr = 1;
14393 			/* lscwnd=0 */
14394 			rack->r_limit_scw = 0;
14395 		}
14396 		break;
14397 	case TCP_SHARED_CWND_TIME_LIMIT:
14398 		RACK_OPTS_INC(tcp_lscwnd);
14399 		if (optval)
14400 			rack->r_limit_scw = 1;
14401 		else
14402 			rack->r_limit_scw = 0;
14403 		break;
14404  	case TCP_RACK_PACE_TO_FILL:
14405 		RACK_OPTS_INC(tcp_fillcw);
14406 		if (optval == 0)
14407 			rack->rc_pace_to_cwnd = 0;
14408 		else
14409 			rack->rc_pace_to_cwnd = 1;
14410 		if ((optval >= rack_gp_rtt_maxmul) &&
14411 		    rack_gp_rtt_maxmul &&
14412 		    (optval < 0xf)) {
14413 			rack->rc_pace_fill_if_rttin_range = 1;
14414 			rack->rtt_limit_mul = optval;
14415 		} else {
14416 			rack->rc_pace_fill_if_rttin_range = 0;
14417 			rack->rtt_limit_mul = 0;
14418 		}
14419 		break;
14420 	case TCP_RACK_NO_PUSH_AT_MAX:
14421 		RACK_OPTS_INC(tcp_npush);
14422 		if (optval == 0)
14423 			rack->r_ctl.rc_no_push_at_mrtt = 0;
14424 		else if (optval < 0xff)
14425 			rack->r_ctl.rc_no_push_at_mrtt = optval;
14426 		else
14427 			error = EINVAL;
14428 		break;
14429 	case TCP_SHARED_CWND_ENABLE:
14430 		RACK_OPTS_INC(tcp_rack_scwnd);
14431 		if (optval == 0)
14432 			rack->rack_enable_scwnd = 0;
14433 		else
14434 			rack->rack_enable_scwnd = 1;
14435 		break;
14436 	case TCP_RACK_MBUF_QUEUE:
14437 		/* Now do we use the LRO mbuf-queue feature */
14438 		RACK_OPTS_INC(tcp_rack_mbufq);
14439 		if (optval)
14440 			rack->r_mbuf_queue = 1;
14441 		else
14442 			rack->r_mbuf_queue = 0;
14443 		if  (rack->r_mbuf_queue || rack->rc_always_pace)
14444 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
14445 		else
14446 			tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
14447 		break;
14448 	case TCP_RACK_NONRXT_CFG_RATE:
14449 		RACK_OPTS_INC(tcp_rack_cfg_rate);
14450 		if (optval == 0)
14451 			rack->rack_rec_nonrxt_use_cr = 0;
14452 		else
14453 			rack->rack_rec_nonrxt_use_cr = 1;
14454 		break;
14455 	case TCP_NO_PRR:
14456 		RACK_OPTS_INC(tcp_rack_noprr);
14457 		if (optval == 0)
14458 			rack->rack_no_prr = 0;
14459 		else
14460 			rack->rack_no_prr = 1;
14461 		break;
14462 	case TCP_TIMELY_DYN_ADJ:
14463 		RACK_OPTS_INC(tcp_timely_dyn);
14464 		if (optval == 0)
14465 			rack->rc_gp_dyn_mul = 0;
14466 		else {
14467 			rack->rc_gp_dyn_mul = 1;
14468 			if (optval >= 100) {
14469 				/*
14470 				 * If the user sets something 100 or more
14471 				 * its the gp_ca value.
14472 				 */
14473 				rack->r_ctl.rack_per_of_gp_ca  = optval;
14474 			}
14475 		}
14476 		break;
14477 	case TCP_RACK_DO_DETECTION:
14478 		RACK_OPTS_INC(tcp_rack_do_detection);
14479 		if (optval == 0)
14480 			rack->do_detection = 0;
14481 		else
14482 			rack->do_detection = 1;
14483 		break;
14484 	case TCP_RACK_PROP_RATE:
14485 		if ((optval <= 0) || (optval >= 100)) {
14486 			error = EINVAL;
14487 			break;
14488 		}
14489 		RACK_OPTS_INC(tcp_rack_prop_rate);
14490 		rack->r_ctl.rc_prop_rate = optval;
14491 		break;
14492 	case TCP_RACK_TLP_USE:
14493 		if ((optval < TLP_USE_ID) || (optval > TLP_USE_TWO_TWO)) {
14494 			error = EINVAL;
14495 			break;
14496 		}
14497 		RACK_OPTS_INC(tcp_tlp_use);
14498 		rack->rack_tlp_threshold_use = optval;
14499 		break;
14500 	case TCP_RACK_PROP:
14501 		/* RACK proportional rate reduction (bool) */
14502 		RACK_OPTS_INC(tcp_rack_prop);
14503 		rack->r_ctl.rc_prop_reduce = optval;
14504 		break;
14505 	case TCP_RACK_TLP_REDUCE:
14506 		/* RACK TLP cwnd reduction (bool) */
14507 		RACK_OPTS_INC(tcp_rack_tlp_reduce);
14508 		rack->r_ctl.rc_tlp_cwnd_reduce = optval;
14509 		break;
14510 	case TCP_RACK_EARLY_RECOV:
14511 		/* Should recovery happen early (bool) */
14512 		RACK_OPTS_INC(tcp_rack_early_recov);
14513 		rack->r_ctl.rc_early_recovery = optval;
14514 		break;
14515 
14516         /*  Pacing related ones */
14517 	case TCP_RACK_PACE_ALWAYS:
14518 		/*
14519 		 * zero is old rack method, 1 is new
14520 		 * method using a pacing rate.
14521 		 */
14522 		RACK_OPTS_INC(tcp_rack_pace_always);
14523 		if (optval > 0)
14524 			rack->rc_always_pace = 1;
14525 		else
14526 			rack->rc_always_pace = 0;
14527 		if  (rack->r_mbuf_queue || rack->rc_always_pace)
14528 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
14529 		else
14530 			tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
14531 		/* A rate may be set irate or other, if so set seg size */
14532 		rack_update_seg(rack);
14533 		break;
14534 	case TCP_BBR_RACK_INIT_RATE:
14535 		RACK_OPTS_INC(tcp_initial_rate);
14536 		val = optval;
14537 		/* Change from kbits per second to bytes per second */
14538 		val *= 1000;
14539 		val /= 8;
14540 		rack->r_ctl.init_rate = val;
14541 		if (rack->rc_init_win != rack_default_init_window) {
14542 			uint32_t win, snt;
14543 
14544 			/*
14545 			 * Options don't always get applied
14546 			 * in the order you think. So in order
14547 			 * to assure we update a cwnd we need
14548 			 * to check and see if we are still
14549 			 * where we should raise the cwnd.
14550 			 */
14551 			win = rc_init_window(rack);
14552 			if (SEQ_GT(tp->snd_max, tp->iss))
14553 				snt = tp->snd_max - tp->iss;
14554 			else
14555 				snt = 0;
14556 			if ((snt < win) &&
14557 			    (tp->snd_cwnd < win))
14558 				tp->snd_cwnd = win;
14559 		}
14560 		if (rack->rc_always_pace)
14561 			rack_update_seg(rack);
14562 		break;
14563 	case TCP_BBR_IWINTSO:
14564 		RACK_OPTS_INC(tcp_initial_win);
14565 		if (optval && (optval <= 0xff)) {
14566 			uint32_t win, snt;
14567 
14568 			rack->rc_init_win = optval;
14569 			win = rc_init_window(rack);
14570 			if (SEQ_GT(tp->snd_max, tp->iss))
14571 				snt = tp->snd_max - tp->iss;
14572 			else
14573 				snt = 0;
14574 			if ((snt < win) &&
14575 			    (tp->t_srtt |
14576 #ifdef NETFLIX_PEAKRATE
14577 			     tp->t_maxpeakrate |
14578 #endif
14579 			     rack->r_ctl.init_rate)) {
14580 				/*
14581 				 * We are not past the initial window
14582 				 * and we have some bases for pacing,
14583 				 * so we need to possibly adjust up
14584 				 * the cwnd. Note even if we don't set
14585 				 * the cwnd, its still ok to raise the rc_init_win
14586 				 * which can be used coming out of idle when we
14587 				 * would have a rate.
14588 				 */
14589 				if (tp->snd_cwnd < win)
14590 					tp->snd_cwnd = win;
14591 			}
14592 			if (rack->rc_always_pace)
14593 				rack_update_seg(rack);
14594 		} else
14595 			error = EINVAL;
14596 		break;
14597 	case TCP_RACK_FORCE_MSEG:
14598 		RACK_OPTS_INC(tcp_rack_force_max_seg);
14599 		if (optval)
14600 			rack->rc_force_max_seg = 1;
14601 		else
14602 			rack->rc_force_max_seg = 0;
14603 		break;
14604 	case TCP_RACK_PACE_MAX_SEG:
14605 		/* Max segments size in a pace in bytes */
14606 		RACK_OPTS_INC(tcp_rack_max_seg);
14607 		rack->rc_user_set_max_segs = optval;
14608 		rack_set_pace_segments(tp, rack, __LINE__);
14609 		break;
14610 	case TCP_RACK_PACE_RATE_REC:
14611 		/* Set the fixed pacing rate in Bytes per second ca */
14612 		RACK_OPTS_INC(tcp_rack_pace_rate_rec);
14613 		rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
14614 		if (rack->r_ctl.rc_fixed_pacing_rate_ca == 0)
14615 			rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
14616 		if (rack->r_ctl.rc_fixed_pacing_rate_ss == 0)
14617 			rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
14618 		rack->use_fixed_rate = 1;
14619 		rack_log_pacing_delay_calc(rack,
14620 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
14621 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
14622 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
14623 					   __LINE__, NULL);
14624 		break;
14625 
14626 	case TCP_RACK_PACE_RATE_SS:
14627 		/* Set the fixed pacing rate in Bytes per second ca */
14628 		RACK_OPTS_INC(tcp_rack_pace_rate_ss);
14629 		rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
14630 		if (rack->r_ctl.rc_fixed_pacing_rate_ca == 0)
14631 			rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
14632 		if (rack->r_ctl.rc_fixed_pacing_rate_rec == 0)
14633 			rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
14634 		rack->use_fixed_rate = 1;
14635 		rack_log_pacing_delay_calc(rack,
14636 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
14637 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
14638 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
14639 					   __LINE__, NULL);
14640 		break;
14641 
14642 	case TCP_RACK_PACE_RATE_CA:
14643 		/* Set the fixed pacing rate in Bytes per second ca */
14644 		RACK_OPTS_INC(tcp_rack_pace_rate_ca);
14645 		rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
14646 		if (rack->r_ctl.rc_fixed_pacing_rate_ss == 0)
14647 			rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
14648 		if (rack->r_ctl.rc_fixed_pacing_rate_rec == 0)
14649 			rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
14650 		rack->use_fixed_rate = 1;
14651 		rack_log_pacing_delay_calc(rack,
14652 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
14653 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
14654 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
14655 					   __LINE__, NULL);
14656 		break;
14657 	case TCP_RACK_GP_INCREASE_REC:
14658 		RACK_OPTS_INC(tcp_gp_inc_rec);
14659 		rack->r_ctl.rack_per_of_gp_rec = optval;
14660 		rack_log_pacing_delay_calc(rack,
14661 					   rack->r_ctl.rack_per_of_gp_ss,
14662 					   rack->r_ctl.rack_per_of_gp_ca,
14663 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
14664 					   __LINE__, NULL);
14665 		break;
14666 	case TCP_RACK_GP_INCREASE_CA:
14667 		RACK_OPTS_INC(tcp_gp_inc_ca);
14668 		ca = optval;
14669 		if (ca < 100) {
14670 			/*
14671 			 * We don't allow any reduction
14672 			 * over the GP b/w.
14673 			 */
14674 			error = EINVAL;
14675 			break;
14676 		}
14677 		rack->r_ctl.rack_per_of_gp_ca = ca;
14678 		rack_log_pacing_delay_calc(rack,
14679 					   rack->r_ctl.rack_per_of_gp_ss,
14680 					   rack->r_ctl.rack_per_of_gp_ca,
14681 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
14682 					   __LINE__, NULL);
14683 		break;
14684 	case TCP_RACK_GP_INCREASE_SS:
14685 		RACK_OPTS_INC(tcp_gp_inc_ss);
14686 		ss = optval;
14687 		if (ss < 100) {
14688 			/*
14689 			 * We don't allow any reduction
14690 			 * over the GP b/w.
14691 			 */
14692 			error = EINVAL;
14693 			break;
14694 		}
14695 		rack->r_ctl.rack_per_of_gp_ss = ss;
14696 		rack_log_pacing_delay_calc(rack,
14697 					   rack->r_ctl.rack_per_of_gp_ss,
14698 					   rack->r_ctl.rack_per_of_gp_ca,
14699 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
14700 					   __LINE__, NULL);
14701 		break;
14702 	case TCP_RACK_RR_CONF:
14703 		RACK_OPTS_INC(tcp_rack_rrr_no_conf_rate);
14704 		if (optval && optval <= 3)
14705 			rack->r_rr_config = optval;
14706 		else
14707 			rack->r_rr_config = 0;
14708 		break;
14709 	case TCP_BBR_HDWR_PACE:
14710 		RACK_OPTS_INC(tcp_hdwr_pacing);
14711 		if (optval){
14712 			if (rack->rack_hdrw_pacing == 0) {
14713 				rack->rack_hdw_pace_ena = 1;
14714 				rack->rack_attempt_hdwr_pace = 0;
14715 			} else
14716 				error = EALREADY;
14717 		} else {
14718 			rack->rack_hdw_pace_ena = 0;
14719 #ifdef RATELIMIT
14720 			if (rack->rack_hdrw_pacing) {
14721 				rack->rack_hdrw_pacing = 0;
14722 				in_pcbdetach_txrtlmt(rack->rc_inp);
14723 			}
14724 #endif
14725 		}
14726 		break;
14727         /*  End Pacing related ones */
14728 	case TCP_RACK_PRR_SENDALOT:
14729 		/* Allow PRR to send more than one seg */
14730 		RACK_OPTS_INC(tcp_rack_prr_sendalot);
14731 		rack->r_ctl.rc_prr_sendalot = optval;
14732 		break;
14733 	case TCP_RACK_MIN_TO:
14734 		/* Minimum time between rack t-o's in ms */
14735 		RACK_OPTS_INC(tcp_rack_min_to);
14736 		rack->r_ctl.rc_min_to = optval;
14737 		break;
14738 	case TCP_RACK_EARLY_SEG:
14739 		/* If early recovery max segments */
14740 		RACK_OPTS_INC(tcp_rack_early_seg);
14741 		rack->r_ctl.rc_early_recovery_segs = optval;
14742 		break;
14743 	case TCP_RACK_REORD_THRESH:
14744 		/* RACK reorder threshold (shift amount) */
14745 		RACK_OPTS_INC(tcp_rack_reord_thresh);
14746 		if ((optval > 0) && (optval < 31))
14747 			rack->r_ctl.rc_reorder_shift = optval;
14748 		else
14749 			error = EINVAL;
14750 		break;
14751 	case TCP_RACK_REORD_FADE:
14752 		/* Does reordering fade after ms time */
14753 		RACK_OPTS_INC(tcp_rack_reord_fade);
14754 		rack->r_ctl.rc_reorder_fade = optval;
14755 		break;
14756 	case TCP_RACK_TLP_THRESH:
14757 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
14758 		RACK_OPTS_INC(tcp_rack_tlp_thresh);
14759 		if (optval)
14760 			rack->r_ctl.rc_tlp_threshold = optval;
14761 		else
14762 			error = EINVAL;
14763 		break;
14764 	case TCP_BBR_USE_RACK_RR:
14765 		RACK_OPTS_INC(tcp_rack_rr);
14766 		if (optval)
14767 			rack->use_rack_rr = 1;
14768 		else
14769 			rack->use_rack_rr = 0;
14770 		break;
14771 	case TCP_RACK_PKT_DELAY:
14772 		/* RACK added ms i.e. rack-rtt + reord + N */
14773 		RACK_OPTS_INC(tcp_rack_pkt_delay);
14774 		rack->r_ctl.rc_pkt_delay = optval;
14775 		break;
14776 	case TCP_RACK_TLP_INC_VAR:
14777 		/* Does TLP include rtt variance in t-o */
14778 		error = EINVAL;
14779 		break;
14780 	case TCP_RACK_IDLE_REDUCE_HIGH:
14781 		error = EINVAL;
14782 		break;
14783 	case TCP_DELACK:
14784 		if (optval == 0)
14785 			tp->t_delayed_ack = 0;
14786 		else
14787 			tp->t_delayed_ack = 1;
14788 		if (tp->t_flags & TF_DELACK) {
14789 			tp->t_flags &= ~TF_DELACK;
14790 			tp->t_flags |= TF_ACKNOW;
14791 			NET_EPOCH_ENTER(et);
14792 			rack_output(tp);
14793 			NET_EPOCH_EXIT(et);
14794 		}
14795 		break;
14796 
14797 	case TCP_BBR_RACK_RTT_USE:
14798 		if ((optval != USE_RTT_HIGH) &&
14799 		    (optval != USE_RTT_LOW) &&
14800 		    (optval != USE_RTT_AVG))
14801 			error = EINVAL;
14802 		else
14803 			rack->r_ctl.rc_rate_sample_method = optval;
14804 		break;
14805 	case TCP_DATA_AFTER_CLOSE:
14806 		if (optval)
14807 			rack->rc_allow_data_af_clo = 1;
14808 		else
14809 			rack->rc_allow_data_af_clo = 0;
14810 		break;
14811 	case TCP_RACK_PACE_REDUCE:
14812 		/* sysctl only now */
14813 		error = EINVAL;
14814 		break;
14815 	default:
14816 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14817 		break;
14818 	}
14819 #ifdef NETFLIX_STATS
14820 	tcp_log_socket_option(tp, sopt->sopt_name, optval, error);
14821 #endif
14822 	INP_WUNLOCK(inp);
14823 	return (error);
14824 }
14825 
14826 static int
14827 rack_get_sockopt(struct socket *so, struct sockopt *sopt,
14828     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack)
14829 {
14830 	int32_t error, optval;
14831 	uint64_t val;
14832 	/*
14833 	 * Because all our options are either boolean or an int, we can just
14834 	 * pull everything into optval and then unlock and copy. If we ever
14835 	 * add a option that is not a int, then this will have quite an
14836 	 * impact to this routine.
14837 	 */
14838 	error = 0;
14839 	switch (sopt->sopt_name) {
14840 	case TCP_RACK_PROFILE:
14841 		/* You cannot retrieve a profile, its write only */
14842 		error = EINVAL;
14843 		break;
14844 	case TCP_RACK_PACE_TO_FILL:
14845 		optval = rack->rc_pace_to_cwnd;
14846 		break;
14847 	case TCP_RACK_NO_PUSH_AT_MAX:
14848 		optval = rack->r_ctl.rc_no_push_at_mrtt;
14849 		break;
14850 	case TCP_SHARED_CWND_ENABLE:
14851 		optval = rack->rack_enable_scwnd;
14852 		break;
14853 	case TCP_RACK_NONRXT_CFG_RATE:
14854 		optval = rack->rack_rec_nonrxt_use_cr;
14855 		break;
14856 	case TCP_NO_PRR:
14857 		optval = rack->rack_no_prr;
14858 		break;
14859 	case TCP_RACK_DO_DETECTION:
14860 		optval = rack->do_detection;
14861 		break;
14862 	case TCP_RACK_MBUF_QUEUE:
14863 		/* Now do we use the LRO mbuf-queue feature */
14864 		optval = rack->r_mbuf_queue;
14865 		break;
14866 	case TCP_TIMELY_DYN_ADJ:
14867 		optval = rack->rc_gp_dyn_mul;
14868 		break;
14869 	case TCP_BBR_IWINTSO:
14870 		optval = rack->rc_init_win;
14871 		break;
14872 	case TCP_RACK_PROP_RATE:
14873 		optval = rack->r_ctl.rc_prop_rate;
14874 		break;
14875 	case TCP_RACK_PROP:
14876 		/* RACK proportional rate reduction (bool) */
14877 		optval = rack->r_ctl.rc_prop_reduce;
14878 		break;
14879 	case TCP_RACK_TLP_REDUCE:
14880 		/* RACK TLP cwnd reduction (bool) */
14881 		optval = rack->r_ctl.rc_tlp_cwnd_reduce;
14882 		break;
14883 	case TCP_RACK_EARLY_RECOV:
14884 		/* Should recovery happen early (bool) */
14885 		optval = rack->r_ctl.rc_early_recovery;
14886 		break;
14887 	case TCP_RACK_PACE_REDUCE:
14888 		/* RACK Hptsi reduction factor (divisor) */
14889 		error = EINVAL;
14890 		break;
14891 	case TCP_BBR_RACK_INIT_RATE:
14892 		val = rack->r_ctl.init_rate;
14893 		/* convert to kbits per sec */
14894 		val *= 8;
14895 		val /= 1000;
14896 		optval = (uint32_t)val;
14897 		break;
14898 	case TCP_RACK_FORCE_MSEG:
14899 		optval = rack->rc_force_max_seg;
14900 		break;
14901 	case TCP_RACK_PACE_MAX_SEG:
14902 		/* Max segments in a pace */
14903 		optval = rack->rc_user_set_max_segs;
14904 		break;
14905 	case TCP_RACK_PACE_ALWAYS:
14906 		/* Use the always pace method */
14907 		optval = rack->rc_always_pace;
14908 		break;
14909 	case TCP_RACK_PRR_SENDALOT:
14910 		/* Allow PRR to send more than one seg */
14911 		optval = rack->r_ctl.rc_prr_sendalot;
14912 		break;
14913 	case TCP_RACK_MIN_TO:
14914 		/* Minimum time between rack t-o's in ms */
14915 		optval = rack->r_ctl.rc_min_to;
14916 		break;
14917 	case TCP_RACK_EARLY_SEG:
14918 		/* If early recovery max segments */
14919 		optval = rack->r_ctl.rc_early_recovery_segs;
14920 		break;
14921 	case TCP_RACK_REORD_THRESH:
14922 		/* RACK reorder threshold (shift amount) */
14923 		optval = rack->r_ctl.rc_reorder_shift;
14924 		break;
14925 	case TCP_RACK_REORD_FADE:
14926 		/* Does reordering fade after ms time */
14927 		optval = rack->r_ctl.rc_reorder_fade;
14928 		break;
14929 	case TCP_BBR_USE_RACK_RR:
14930 		/* Do we use the rack cheat for rxt */
14931 		optval = rack->use_rack_rr;
14932 		break;
14933 	case TCP_RACK_RR_CONF:
14934 		optval = rack->r_rr_config;
14935 		break;
14936 	case TCP_BBR_HDWR_PACE:
14937 		optval = rack->rack_hdw_pace_ena;
14938 		break;
14939 	case TCP_RACK_TLP_THRESH:
14940 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
14941 		optval = rack->r_ctl.rc_tlp_threshold;
14942 		break;
14943 	case TCP_RACK_PKT_DELAY:
14944 		/* RACK added ms i.e. rack-rtt + reord + N */
14945 		optval = rack->r_ctl.rc_pkt_delay;
14946 		break;
14947 	case TCP_RACK_TLP_USE:
14948 		optval = rack->rack_tlp_threshold_use;
14949 		break;
14950 	case TCP_RACK_TLP_INC_VAR:
14951 		/* Does TLP include rtt variance in t-o */
14952 		error = EINVAL;
14953 		break;
14954 	case TCP_RACK_IDLE_REDUCE_HIGH:
14955 		error = EINVAL;
14956 		break;
14957 	case TCP_RACK_PACE_RATE_CA:
14958 		optval = rack->r_ctl.rc_fixed_pacing_rate_ca;
14959 		break;
14960 	case TCP_RACK_PACE_RATE_SS:
14961 		optval = rack->r_ctl.rc_fixed_pacing_rate_ss;
14962 		break;
14963 	case TCP_RACK_PACE_RATE_REC:
14964 		optval = rack->r_ctl.rc_fixed_pacing_rate_rec;
14965 		break;
14966 	case TCP_RACK_GP_INCREASE_SS:
14967 		optval = rack->r_ctl.rack_per_of_gp_ca;
14968 		break;
14969 	case TCP_RACK_GP_INCREASE_CA:
14970 		optval = rack->r_ctl.rack_per_of_gp_ss;
14971 		break;
14972 	case TCP_BBR_RACK_RTT_USE:
14973 		optval = rack->r_ctl.rc_rate_sample_method;
14974 		break;
14975 	case TCP_DELACK:
14976 		optval = tp->t_delayed_ack;
14977 		break;
14978 	case TCP_DATA_AFTER_CLOSE:
14979 		optval = rack->rc_allow_data_af_clo;
14980 		break;
14981 	case TCP_SHARED_CWND_TIME_LIMIT:
14982 		optval = rack->r_limit_scw;
14983 		break;
14984 	default:
14985 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14986 		break;
14987 	}
14988 	INP_WUNLOCK(inp);
14989 	if (error == 0) {
14990 		error = sooptcopyout(sopt, &optval, sizeof optval);
14991 	}
14992 	return (error);
14993 }
14994 
14995 static int
14996 rack_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp)
14997 {
14998 	int32_t error = EINVAL;
14999 	struct tcp_rack *rack;
15000 
15001 	rack = (struct tcp_rack *)tp->t_fb_ptr;
15002 	if (rack == NULL) {
15003 		/* Huh? */
15004 		goto out;
15005 	}
15006 	if (sopt->sopt_dir == SOPT_SET) {
15007 		return (rack_set_sockopt(so, sopt, inp, tp, rack));
15008 	} else if (sopt->sopt_dir == SOPT_GET) {
15009 		return (rack_get_sockopt(so, sopt, inp, tp, rack));
15010 	}
15011 out:
15012 	INP_WUNLOCK(inp);
15013 	return (error);
15014 }
15015 
15016 static int
15017 rack_pru_options(struct tcpcb *tp, int flags)
15018 {
15019 	if (flags & PRUS_OOB)
15020 		return (EOPNOTSUPP);
15021 	return (0);
15022 }
15023 
15024 static struct tcp_function_block __tcp_rack = {
15025 	.tfb_tcp_block_name = __XSTRING(STACKNAME),
15026 	.tfb_tcp_output = rack_output,
15027 	.tfb_do_queued_segments = ctf_do_queued_segments,
15028 	.tfb_do_segment_nounlock = rack_do_segment_nounlock,
15029 	.tfb_tcp_do_segment = rack_do_segment,
15030 	.tfb_tcp_ctloutput = rack_ctloutput,
15031 	.tfb_tcp_fb_init = rack_init,
15032 	.tfb_tcp_fb_fini = rack_fini,
15033 	.tfb_tcp_timer_stop_all = rack_stopall,
15034 	.tfb_tcp_timer_activate = rack_timer_activate,
15035 	.tfb_tcp_timer_active = rack_timer_active,
15036 	.tfb_tcp_timer_stop = rack_timer_stop,
15037 	.tfb_tcp_rexmit_tmr = rack_remxt_tmr,
15038 	.tfb_tcp_handoff_ok = rack_handoff_ok,
15039 	.tfb_pru_options = rack_pru_options,
15040 };
15041 
15042 static const char *rack_stack_names[] = {
15043 	__XSTRING(STACKNAME),
15044 #ifdef STACKALIAS
15045 	__XSTRING(STACKALIAS),
15046 #endif
15047 };
15048 
15049 static int
15050 rack_ctor(void *mem, int32_t size, void *arg, int32_t how)
15051 {
15052 	memset(mem, 0, size);
15053 	return (0);
15054 }
15055 
15056 static void
15057 rack_dtor(void *mem, int32_t size, void *arg)
15058 {
15059 
15060 }
15061 
15062 static bool rack_mod_inited = false;
15063 
15064 static int
15065 tcp_addrack(module_t mod, int32_t type, void *data)
15066 {
15067 	int32_t err = 0;
15068 	int num_stacks;
15069 
15070 	switch (type) {
15071 	case MOD_LOAD:
15072 		rack_zone = uma_zcreate(__XSTRING(MODNAME) "_map",
15073 		    sizeof(struct rack_sendmap),
15074 		    rack_ctor, rack_dtor, NULL, NULL, UMA_ALIGN_PTR, 0);
15075 
15076 		rack_pcb_zone = uma_zcreate(__XSTRING(MODNAME) "_pcb",
15077 		    sizeof(struct tcp_rack),
15078 		    rack_ctor, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
15079 
15080 		sysctl_ctx_init(&rack_sysctl_ctx);
15081 		rack_sysctl_root = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
15082 		    SYSCTL_STATIC_CHILDREN(_net_inet_tcp),
15083 		    OID_AUTO,
15084 #ifdef STACKALIAS
15085 		    __XSTRING(STACKALIAS),
15086 #else
15087 		    __XSTRING(STACKNAME),
15088 #endif
15089 		    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
15090 		    "");
15091 		if (rack_sysctl_root == NULL) {
15092 			printf("Failed to add sysctl node\n");
15093 			err = EFAULT;
15094 			goto free_uma;
15095 		}
15096 		rack_init_sysctls();
15097 		num_stacks = nitems(rack_stack_names);
15098 		err = register_tcp_functions_as_names(&__tcp_rack, M_WAITOK,
15099 		    rack_stack_names, &num_stacks);
15100 		if (err) {
15101 			printf("Failed to register %s stack name for "
15102 			    "%s module\n", rack_stack_names[num_stacks],
15103 			    __XSTRING(MODNAME));
15104 			sysctl_ctx_free(&rack_sysctl_ctx);
15105 free_uma:
15106 			uma_zdestroy(rack_zone);
15107 			uma_zdestroy(rack_pcb_zone);
15108 			rack_counter_destroy();
15109 			printf("Failed to register rack module -- err:%d\n", err);
15110 			return (err);
15111 		}
15112 		tcp_lro_reg_mbufq();
15113 		rack_mod_inited = true;
15114 		break;
15115 	case MOD_QUIESCE:
15116 		err = deregister_tcp_functions(&__tcp_rack, true, false);
15117 		break;
15118 	case MOD_UNLOAD:
15119 		err = deregister_tcp_functions(&__tcp_rack, false, true);
15120 		if (err == EBUSY)
15121 			break;
15122 		if (rack_mod_inited) {
15123 			uma_zdestroy(rack_zone);
15124 			uma_zdestroy(rack_pcb_zone);
15125 			sysctl_ctx_free(&rack_sysctl_ctx);
15126 			rack_counter_destroy();
15127 			rack_mod_inited = false;
15128 		}
15129 		tcp_lro_dereg_mbufq();
15130 		err = 0;
15131 		break;
15132 	default:
15133 		return (EOPNOTSUPP);
15134 	}
15135 	return (err);
15136 }
15137 
15138 static moduledata_t tcp_rack = {
15139 	.name = __XSTRING(MODNAME),
15140 	.evhand = tcp_addrack,
15141 	.priv = 0
15142 };
15143 
15144 MODULE_VERSION(MODNAME, 1);
15145 DECLARE_MODULE(MODNAME, tcp_rack, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
15146 MODULE_DEPEND(MODNAME, tcphpts, 1, 1, 1);
15147