xref: /freebsd/sys/netinet/tcp_var.h (revision 3157ba21)
1 /*-
2  * Copyright (c) 1982, 1986, 1993, 1994, 1995
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	@(#)tcp_var.h	8.4 (Berkeley) 5/24/95
30  * $FreeBSD$
31  */
32 
33 #ifndef _NETINET_TCP_VAR_H_
34 #define _NETINET_TCP_VAR_H_
35 
36 #include <netinet/tcp.h>
37 
38 #ifdef _KERNEL
39 #include <net/vnet.h>
40 
41 /*
42  * Kernel variables for tcp.
43  */
44 VNET_DECLARE(int, tcp_do_rfc1323);
45 #define	V_tcp_do_rfc1323	VNET(tcp_do_rfc1323)
46 
47 VNET_DECLARE(int, tcp_reass_qsize);
48 VNET_DECLARE(struct uma_zone *, tcp_reass_zone);
49 #define	V_tcp_reass_qsize	VNET(tcp_reass_qsize)
50 #define	V_tcp_reass_zone	VNET(tcp_reass_zone)
51 #endif /* _KERNEL */
52 
53 /* TCP segment queue entry */
54 struct tseg_qent {
55 	LIST_ENTRY(tseg_qent) tqe_q;
56 	int	tqe_len;		/* TCP segment data length */
57 	struct	tcphdr *tqe_th;		/* a pointer to tcp header */
58 	struct	mbuf	*tqe_m;		/* mbuf contains packet */
59 };
60 LIST_HEAD(tsegqe_head, tseg_qent);
61 
62 struct sackblk {
63 	tcp_seq start;		/* start seq no. of sack block */
64 	tcp_seq end;		/* end seq no. */
65 };
66 
67 struct sackhole {
68 	tcp_seq start;		/* start seq no. of hole */
69 	tcp_seq end;		/* end seq no. */
70 	tcp_seq rxmit;		/* next seq. no in hole to be retransmitted */
71 	TAILQ_ENTRY(sackhole) scblink;	/* scoreboard linkage */
72 };
73 
74 struct sackhint {
75 	struct sackhole	*nexthole;
76 	int		sack_bytes_rexmit;
77 
78 	int		ispare;		/* explicit pad for 64bit alignment */
79 	uint64_t	_pad[2];	/* 1 sacked_bytes, 1 TBD */
80 };
81 
82 struct tcptemp {
83 	u_char	tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */
84 	struct	tcphdr tt_t;
85 };
86 
87 #define tcp6cb		tcpcb  /* for KAME src sync over BSD*'s */
88 
89 /* Neighbor Discovery, Neighbor Unreachability Detection Upper layer hint. */
90 #ifdef INET6
91 #define ND6_HINT(tp)						\
92 do {								\
93 	if ((tp) && (tp)->t_inpcb &&				\
94 	    ((tp)->t_inpcb->inp_vflag & INP_IPV6) != 0)		\
95 		nd6_nud_hint(NULL, NULL, 0);			\
96 } while (0)
97 #else
98 #define ND6_HINT(tp)
99 #endif
100 
101 /*
102  * Tcp control block, one per tcp; fields:
103  * Organized for 16 byte cacheline efficiency.
104  */
105 struct tcpcb {
106 	struct	tsegqe_head t_segq;	/* segment reassembly queue */
107 	void	*t_pspare[2];		/* new reassembly queue */
108 	int	t_segqlen;		/* segment reassembly queue length */
109 	int	t_dupacks;		/* consecutive dup acks recd */
110 
111 	struct tcp_timer *t_timers;	/* All the TCP timers in one struct */
112 
113 	struct	inpcb *t_inpcb;		/* back pointer to internet pcb */
114 	int	t_state;		/* state of this connection */
115 	u_int	t_flags;
116 
117 	struct	vnet *t_vnet;		/* back pointer to parent vnet */
118 
119 	tcp_seq	snd_una;		/* send unacknowledged */
120 	tcp_seq	snd_max;		/* highest sequence number sent;
121 					 * used to recognize retransmits
122 					 */
123 	tcp_seq	snd_nxt;		/* send next */
124 	tcp_seq	snd_up;			/* send urgent pointer */
125 
126 	tcp_seq	snd_wl1;		/* window update seg seq number */
127 	tcp_seq	snd_wl2;		/* window update seg ack number */
128 	tcp_seq	iss;			/* initial send sequence number */
129 	tcp_seq	irs;			/* initial receive sequence number */
130 
131 	tcp_seq	rcv_nxt;		/* receive next */
132 	tcp_seq	rcv_adv;		/* advertised window */
133 	u_long	rcv_wnd;		/* receive window */
134 	tcp_seq	rcv_up;			/* receive urgent pointer */
135 
136 	u_long	snd_wnd;		/* send window */
137 	u_long	snd_cwnd;		/* congestion-controlled window */
138 	u_long	snd_bwnd;		/* bandwidth-controlled window */
139 	u_long	snd_ssthresh;		/* snd_cwnd size threshold for
140 					 * for slow start exponential to
141 					 * linear switch
142 					 */
143 	u_long	snd_bandwidth;		/* calculated bandwidth or 0 */
144 	tcp_seq	snd_recover;		/* for use in NewReno Fast Recovery */
145 
146 	u_int	t_maxopd;		/* mss plus options */
147 
148 	u_int	t_rcvtime;		/* inactivity time */
149 	u_int	t_starttime;		/* time connection was established */
150 	u_int	t_rtttime;		/* RTT measurement start time */
151 	tcp_seq	t_rtseq;		/* sequence number being timed */
152 
153 	u_int	t_bw_rtttime;		/* used for bandwidth calculation */
154 	tcp_seq	t_bw_rtseq;		/* used for bandwidth calculation */
155 
156 	int	t_rxtcur;		/* current retransmit value (ticks) */
157 	u_int	t_maxseg;		/* maximum segment size */
158 	int	t_srtt;			/* smoothed round-trip time */
159 	int	t_rttvar;		/* variance in round-trip time */
160 
161 	int	t_rxtshift;		/* log(2) of rexmt exp. backoff */
162 	u_int	t_rttmin;		/* minimum rtt allowed */
163 	u_int	t_rttbest;		/* best rtt we've seen */
164 	u_long	t_rttupdated;		/* number of times rtt sampled */
165 	u_long	max_sndwnd;		/* largest window peer has offered */
166 
167 	int	t_softerror;		/* possible error not yet reported */
168 /* out-of-band data */
169 	char	t_oobflags;		/* have some */
170 	char	t_iobc;			/* input character */
171 /* RFC 1323 variables */
172 	u_char	snd_scale;		/* window scaling for send window */
173 	u_char	rcv_scale;		/* window scaling for recv window */
174 	u_char	request_r_scale;	/* pending window scaling */
175 	u_int32_t  ts_recent;		/* timestamp echo data */
176 	u_int	ts_recent_age;		/* when last updated */
177 	u_int32_t  ts_offset;		/* our timestamp offset */
178 
179 	tcp_seq	last_ack_sent;
180 /* experimental */
181 	u_long	snd_cwnd_prev;		/* cwnd prior to retransmit */
182 	u_long	snd_ssthresh_prev;	/* ssthresh prior to retransmit */
183 	tcp_seq	snd_recover_prev;	/* snd_recover prior to retransmit */
184 	u_int	t_badrxtwin;		/* window for retransmit recovery */
185 	u_char	snd_limited;		/* segments limited transmitted */
186 /* SACK related state */
187 	int	snd_numholes;		/* number of holes seen by sender */
188 	TAILQ_HEAD(sackhole_head, sackhole) snd_holes;
189 					/* SACK scoreboard (sorted) */
190 	tcp_seq	snd_fack;		/* last seq number(+1) sack'd by rcv'r*/
191 	int	rcv_numsacks;		/* # distinct sack blks present */
192 	struct sackblk sackblks[MAX_SACK_BLKS]; /* seq nos. of sack blocks */
193 	tcp_seq sack_newdata;		/* New data xmitted in this recovery
194 					   episode starts at this seq number */
195 	struct sackhint	sackhint;	/* SACK scoreboard hint */
196 	int	t_rttlow;		/* smallest observerved RTT */
197 	u_int32_t	rfbuf_ts;	/* recv buffer autoscaling timestamp */
198 	int	rfbuf_cnt;		/* recv buffer autoscaling byte count */
199 	struct toe_usrreqs *t_tu;	/* offload operations vector */
200 	void	*t_toe;			/* TOE pcb pointer */
201 	int	t_bytes_acked;		/* # bytes acked during current RTT */
202 
203 	int	t_ispare;		/* explicit pad for 64bit alignment */
204 	void	*t_pspare2[6];		/* 2 CC / 4 TBD */
205 	uint64_t _pad[12];		/* 7 UTO, 5 TBD (1-2 CC/RTT?) */
206 };
207 
208 /*
209  * Flags and utility macros for the t_flags field.
210  */
211 #define	TF_ACKNOW	0x000001	/* ack peer immediately */
212 #define	TF_DELACK	0x000002	/* ack, but try to delay it */
213 #define	TF_NODELAY	0x000004	/* don't delay packets to coalesce */
214 #define	TF_NOOPT	0x000008	/* don't use tcp options */
215 #define	TF_SENTFIN	0x000010	/* have sent FIN */
216 #define	TF_REQ_SCALE	0x000020	/* have/will request window scaling */
217 #define	TF_RCVD_SCALE	0x000040	/* other side has requested scaling */
218 #define	TF_REQ_TSTMP	0x000080	/* have/will request timestamps */
219 #define	TF_RCVD_TSTMP	0x000100	/* a timestamp was received in SYN */
220 #define	TF_SACK_PERMIT	0x000200	/* other side said I could SACK */
221 #define	TF_NEEDSYN	0x000400	/* send SYN (implicit state) */
222 #define	TF_NEEDFIN	0x000800	/* send FIN (implicit state) */
223 #define	TF_NOPUSH	0x001000	/* don't push */
224 #define	TF_MORETOCOME	0x010000	/* More data to be appended to sock */
225 #define	TF_LQ_OVERFLOW	0x020000	/* listen queue overflow */
226 #define	TF_LASTIDLE	0x040000	/* connection was previously idle */
227 #define	TF_RXWIN0SENT	0x080000	/* sent a receiver win 0 in response */
228 #define	TF_FASTRECOVERY	0x100000	/* in NewReno Fast Recovery */
229 #define	TF_WASFRECOVERY	0x200000	/* was in NewReno Fast Recovery */
230 #define	TF_SIGNATURE	0x400000	/* require MD5 digests (RFC2385) */
231 #define	TF_FORCEDATA	0x800000	/* force out a byte */
232 #define	TF_TSO		0x1000000	/* TSO enabled on this connection */
233 #define	TF_TOE		0x2000000	/* this connection is offloaded */
234 #define	TF_ECN_PERMIT	0x4000000	/* connection ECN-ready */
235 #define	TF_ECN_SND_CWR	0x8000000	/* ECN CWR in queue */
236 #define	TF_ECN_SND_ECE	0x10000000	/* ECN ECE in queue */
237 
238 #define IN_FASTRECOVERY(tp)	(tp->t_flags & TF_FASTRECOVERY)
239 #define ENTER_FASTRECOVERY(tp)	tp->t_flags |= TF_FASTRECOVERY
240 #define EXIT_FASTRECOVERY(tp)	tp->t_flags &= ~TF_FASTRECOVERY
241 
242 /*
243  * Flags for the t_oobflags field.
244  */
245 #define	TCPOOB_HAVEDATA	0x01
246 #define	TCPOOB_HADDATA	0x02
247 
248 #ifdef TCP_SIGNATURE
249 /*
250  * Defines which are needed by the xform_tcp module and tcp_[in|out]put
251  * for SADB verification and lookup.
252  */
253 #define	TCP_SIGLEN	16	/* length of computed digest in bytes */
254 #define	TCP_KEYLEN_MIN	1	/* minimum length of TCP-MD5 key */
255 #define	TCP_KEYLEN_MAX	80	/* maximum length of TCP-MD5 key */
256 /*
257  * Only a single SA per host may be specified at this time. An SPI is
258  * needed in order for the KEY_ALLOCSA() lookup to work.
259  */
260 #define	TCP_SIG_SPI	0x1000
261 #endif /* TCP_SIGNATURE */
262 
263 /*
264  * Structure to hold TCP options that are only used during segment
265  * processing (in tcp_input), but not held in the tcpcb.
266  * It's basically used to reduce the number of parameters
267  * to tcp_dooptions and tcp_addoptions.
268  * The binary order of the to_flags is relevant for packing of the
269  * options in tcp_addoptions.
270  */
271 struct tcpopt {
272 	u_int64_t	to_flags;	/* which options are present */
273 #define	TOF_MSS		0x0001		/* maximum segment size */
274 #define	TOF_SCALE	0x0002		/* window scaling */
275 #define	TOF_SACKPERM	0x0004		/* SACK permitted */
276 #define	TOF_TS		0x0010		/* timestamp */
277 #define	TOF_SIGNATURE	0x0040		/* TCP-MD5 signature option (RFC2385) */
278 #define	TOF_SACK	0x0080		/* Peer sent SACK option */
279 #define	TOF_MAXOPT	0x0100
280 	u_int32_t	to_tsval;	/* new timestamp */
281 	u_int32_t	to_tsecr;	/* reflected timestamp */
282 	u_char		*to_sacks;	/* pointer to the first SACK blocks */
283 	u_char		*to_signature;	/* pointer to the TCP-MD5 signature */
284 	u_int16_t	to_mss;		/* maximum segment size */
285 	u_int8_t	to_wscale;	/* window scaling */
286 	u_int8_t	to_nsacks;	/* number of SACK blocks */
287 };
288 
289 /*
290  * Flags for tcp_dooptions.
291  */
292 #define	TO_SYN		0x01		/* parse SYN-only options */
293 
294 struct hc_metrics_lite {	/* must stay in sync with hc_metrics */
295 	u_long	rmx_mtu;	/* MTU for this path */
296 	u_long	rmx_ssthresh;	/* outbound gateway buffer limit */
297 	u_long	rmx_rtt;	/* estimated round trip time */
298 	u_long	rmx_rttvar;	/* estimated rtt variance */
299 	u_long	rmx_bandwidth;	/* estimated bandwidth */
300 	u_long	rmx_cwnd;	/* congestion window */
301 	u_long	rmx_sendpipe;   /* outbound delay-bandwidth product */
302 	u_long	rmx_recvpipe;   /* inbound delay-bandwidth product */
303 };
304 
305 #ifndef _NETINET_IN_PCB_H_
306 struct in_conninfo;
307 #endif /* _NETINET_IN_PCB_H_ */
308 
309 struct tcptw {
310 	struct inpcb	*tw_inpcb;	/* XXX back pointer to internet pcb */
311 	tcp_seq		snd_nxt;
312 	tcp_seq		rcv_nxt;
313 	tcp_seq		iss;
314 	tcp_seq		irs;
315 	u_short		last_win;	/* cached window value */
316 	u_short		tw_so_options;	/* copy of so_options */
317 	struct ucred	*tw_cred;	/* user credentials */
318 	u_int32_t	t_recent;
319 	u_int32_t	ts_offset;	/* our timestamp offset */
320 	u_int		t_starttime;
321 	int		tw_time;
322 	TAILQ_ENTRY(tcptw) tw_2msl;
323 };
324 
325 #define	intotcpcb(ip)	((struct tcpcb *)(ip)->inp_ppcb)
326 #define	intotw(ip)	((struct tcptw *)(ip)->inp_ppcb)
327 #define	sototcpcb(so)	(intotcpcb(sotoinpcb(so)))
328 
329 /*
330  * The smoothed round-trip time and estimated variance
331  * are stored as fixed point numbers scaled by the values below.
332  * For convenience, these scales are also used in smoothing the average
333  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
334  * With these scales, srtt has 3 bits to the right of the binary point,
335  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
336  * binary point, and is smoothed with an ALPHA of 0.75.
337  */
338 #define	TCP_RTT_SCALE		32	/* multiplier for srtt; 3 bits frac. */
339 #define	TCP_RTT_SHIFT		5	/* shift for srtt; 3 bits frac. */
340 #define	TCP_RTTVAR_SCALE	16	/* multiplier for rttvar; 2 bits */
341 #define	TCP_RTTVAR_SHIFT	4	/* shift for rttvar; 2 bits */
342 #define	TCP_DELTA_SHIFT		2	/* see tcp_input.c */
343 
344 /*
345  * The initial retransmission should happen at rtt + 4 * rttvar.
346  * Because of the way we do the smoothing, srtt and rttvar
347  * will each average +1/2 tick of bias.  When we compute
348  * the retransmit timer, we want 1/2 tick of rounding and
349  * 1 extra tick because of +-1/2 tick uncertainty in the
350  * firing of the timer.  The bias will give us exactly the
351  * 1.5 tick we need.  But, because the bias is
352  * statistical, we have to test that we don't drop below
353  * the minimum feasible timer (which is 2 ticks).
354  * This version of the macro adapted from a paper by Lawrence
355  * Brakmo and Larry Peterson which outlines a problem caused
356  * by insufficient precision in the original implementation,
357  * which results in inappropriately large RTO values for very
358  * fast networks.
359  */
360 #define	TCP_REXMTVAL(tp) \
361 	max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT))  \
362 	  + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
363 
364 /*
365  * TCP statistics.
366  * Many of these should be kept per connection,
367  * but that's inconvenient at the moment.
368  */
369 struct	tcpstat {
370 	u_long	tcps_connattempt;	/* connections initiated */
371 	u_long	tcps_accepts;		/* connections accepted */
372 	u_long	tcps_connects;		/* connections established */
373 	u_long	tcps_drops;		/* connections dropped */
374 	u_long	tcps_conndrops;		/* embryonic connections dropped */
375 	u_long	tcps_minmssdrops;	/* average minmss too low drops */
376 	u_long	tcps_closed;		/* conn. closed (includes drops) */
377 	u_long	tcps_segstimed;		/* segs where we tried to get rtt */
378 	u_long	tcps_rttupdated;	/* times we succeeded */
379 	u_long	tcps_delack;		/* delayed acks sent */
380 	u_long	tcps_timeoutdrop;	/* conn. dropped in rxmt timeout */
381 	u_long	tcps_rexmttimeo;	/* retransmit timeouts */
382 	u_long	tcps_persisttimeo;	/* persist timeouts */
383 	u_long	tcps_keeptimeo;		/* keepalive timeouts */
384 	u_long	tcps_keepprobe;		/* keepalive probes sent */
385 	u_long	tcps_keepdrops;		/* connections dropped in keepalive */
386 
387 	u_long	tcps_sndtotal;		/* total packets sent */
388 	u_long	tcps_sndpack;		/* data packets sent */
389 	u_long	tcps_sndbyte;		/* data bytes sent */
390 	u_long	tcps_sndrexmitpack;	/* data packets retransmitted */
391 	u_long	tcps_sndrexmitbyte;	/* data bytes retransmitted */
392 	u_long	tcps_sndrexmitbad;	/* unnecessary packet retransmissions */
393 	u_long	tcps_sndacks;		/* ack-only packets sent */
394 	u_long	tcps_sndprobe;		/* window probes sent */
395 	u_long	tcps_sndurg;		/* packets sent with URG only */
396 	u_long	tcps_sndwinup;		/* window update-only packets sent */
397 	u_long	tcps_sndctrl;		/* control (SYN|FIN|RST) packets sent */
398 
399 	u_long	tcps_rcvtotal;		/* total packets received */
400 	u_long	tcps_rcvpack;		/* packets received in sequence */
401 	u_long	tcps_rcvbyte;		/* bytes received in sequence */
402 	u_long	tcps_rcvbadsum;		/* packets received with ccksum errs */
403 	u_long	tcps_rcvbadoff;		/* packets received with bad offset */
404 	u_long	tcps_rcvmemdrop;	/* packets dropped for lack of memory */
405 	u_long	tcps_rcvshort;		/* packets received too short */
406 	u_long	tcps_rcvduppack;	/* duplicate-only packets received */
407 	u_long	tcps_rcvdupbyte;	/* duplicate-only bytes received */
408 	u_long	tcps_rcvpartduppack;	/* packets with some duplicate data */
409 	u_long	tcps_rcvpartdupbyte;	/* dup. bytes in part-dup. packets */
410 	u_long	tcps_rcvoopack;		/* out-of-order packets received */
411 	u_long	tcps_rcvoobyte;		/* out-of-order bytes received */
412 	u_long	tcps_rcvpackafterwin;	/* packets with data after window */
413 	u_long	tcps_rcvbyteafterwin;	/* bytes rcvd after window */
414 	u_long	tcps_rcvafterclose;	/* packets rcvd after "close" */
415 	u_long	tcps_rcvwinprobe;	/* rcvd window probe packets */
416 	u_long	tcps_rcvdupack;		/* rcvd duplicate acks */
417 	u_long	tcps_rcvacktoomuch;	/* rcvd acks for unsent data */
418 	u_long	tcps_rcvackpack;	/* rcvd ack packets */
419 	u_long	tcps_rcvackbyte;	/* bytes acked by rcvd acks */
420 	u_long	tcps_rcvwinupd;		/* rcvd window update packets */
421 	u_long	tcps_pawsdrop;		/* segments dropped due to PAWS */
422 	u_long	tcps_predack;		/* times hdr predict ok for acks */
423 	u_long	tcps_preddat;		/* times hdr predict ok for data pkts */
424 	u_long	tcps_pcbcachemiss;
425 	u_long	tcps_cachedrtt;		/* times cached RTT in route updated */
426 	u_long	tcps_cachedrttvar;	/* times cached rttvar updated */
427 	u_long	tcps_cachedssthresh;	/* times cached ssthresh updated */
428 	u_long	tcps_usedrtt;		/* times RTT initialized from route */
429 	u_long	tcps_usedrttvar;	/* times RTTVAR initialized from rt */
430 	u_long	tcps_usedssthresh;	/* times ssthresh initialized from rt*/
431 	u_long	tcps_persistdrop;	/* timeout in persist state */
432 	u_long	tcps_badsyn;		/* bogus SYN, e.g. premature ACK */
433 	u_long	tcps_mturesent;		/* resends due to MTU discovery */
434 	u_long	tcps_listendrop;	/* listen queue overflows */
435 	u_long	tcps_badrst;		/* ignored RSTs in the window */
436 
437 	u_long	tcps_sc_added;		/* entry added to syncache */
438 	u_long	tcps_sc_retransmitted;	/* syncache entry was retransmitted */
439 	u_long	tcps_sc_dupsyn;		/* duplicate SYN packet */
440 	u_long	tcps_sc_dropped;	/* could not reply to packet */
441 	u_long	tcps_sc_completed;	/* successful extraction of entry */
442 	u_long	tcps_sc_bucketoverflow;	/* syncache per-bucket limit hit */
443 	u_long	tcps_sc_cacheoverflow;	/* syncache cache limit hit */
444 	u_long	tcps_sc_reset;		/* RST removed entry from syncache */
445 	u_long	tcps_sc_stale;		/* timed out or listen socket gone */
446 	u_long	tcps_sc_aborted;	/* syncache entry aborted */
447 	u_long	tcps_sc_badack;		/* removed due to bad ACK */
448 	u_long	tcps_sc_unreach;	/* ICMP unreachable received */
449 	u_long	tcps_sc_zonefail;	/* zalloc() failed */
450 	u_long	tcps_sc_sendcookie;	/* SYN cookie sent */
451 	u_long	tcps_sc_recvcookie;	/* SYN cookie received */
452 
453 	u_long	tcps_hc_added;		/* entry added to hostcache */
454 	u_long	tcps_hc_bucketoverflow;	/* hostcache per bucket limit hit */
455 
456 	u_long  tcps_finwait2_drops;    /* Drop FIN_WAIT_2 connection after time limit */
457 
458 	/* SACK related stats */
459 	u_long	tcps_sack_recovery_episode; /* SACK recovery episodes */
460 	u_long  tcps_sack_rexmits;	    /* SACK rexmit segments   */
461 	u_long  tcps_sack_rexmit_bytes;	    /* SACK rexmit bytes      */
462 	u_long  tcps_sack_rcv_blocks;	    /* SACK blocks (options) received */
463 	u_long  tcps_sack_send_blocks;	    /* SACK blocks (options) sent     */
464 	u_long  tcps_sack_sboverflow; 	    /* times scoreboard overflowed */
465 
466 	/* ECN related stats */
467 	u_long	tcps_ecn_ce;		/* ECN Congestion Experienced */
468 	u_long	tcps_ecn_ect0;		/* ECN Capable Transport */
469 	u_long	tcps_ecn_ect1;		/* ECN Capable Transport */
470 	u_long	tcps_ecn_shs;		/* ECN successful handshakes */
471 	u_long	tcps_ecn_rcwnd;		/* # times ECN reduced the cwnd */
472 
473 	u_long	_pad[12];		/* 6 UTO, 6 TBD */
474 };
475 
476 #ifdef _KERNEL
477 /*
478  * In-kernel consumers can use these accessor macros directly to update
479  * stats.
480  */
481 #define	TCPSTAT_ADD(name, val)	V_tcpstat.name += (val)
482 #define	TCPSTAT_INC(name)	TCPSTAT_ADD(name, 1)
483 
484 /*
485  * Kernel module consumers must use this accessor macro.
486  */
487 void	kmod_tcpstat_inc(int statnum);
488 #define	KMOD_TCPSTAT_INC(name)						\
489 	kmod_tcpstat_inc(offsetof(struct tcpstat, name) / sizeof(u_long))
490 #endif
491 
492 /*
493  * TCB structure exported to user-land via sysctl(3).
494  * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
495  * included.  Not all of our clients do.
496  */
497 #if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
498 struct xtcp_timer {
499 	int tt_rexmt;	/* retransmit timer */
500 	int tt_persist;	/* retransmit persistence */
501 	int tt_keep;	/* keepalive */
502 	int tt_2msl;	/* 2*msl TIME_WAIT timer */
503 	int tt_delack;	/* delayed ACK timer */
504 	int t_rcvtime; 	/* Time since last packet received */
505 };
506 struct	xtcpcb {
507 	size_t	xt_len;
508 	struct	inpcb	xt_inp;
509 	struct	tcpcb	xt_tp;
510 	struct	xsocket	xt_socket;
511 	struct	xtcp_timer xt_timer;
512 	u_quad_t	xt_alignment_hack;
513 };
514 #endif
515 
516 /*
517  * Names for TCP sysctl objects
518  */
519 #define	TCPCTL_DO_RFC1323	1	/* use RFC-1323 extensions */
520 #define	TCPCTL_MSSDFLT		3	/* MSS default */
521 #define TCPCTL_STATS		4	/* statistics (read-only) */
522 #define	TCPCTL_RTTDFLT		5	/* default RTT estimate */
523 #define	TCPCTL_KEEPIDLE		6	/* keepalive idle timer */
524 #define	TCPCTL_KEEPINTVL	7	/* interval to send keepalives */
525 #define	TCPCTL_SENDSPACE	8	/* send buffer space */
526 #define	TCPCTL_RECVSPACE	9	/* receive buffer space */
527 #define	TCPCTL_KEEPINIT		10	/* timeout for establishing syn */
528 #define	TCPCTL_PCBLIST		11	/* list of all outstanding PCBs */
529 #define	TCPCTL_DELACKTIME	12	/* time before sending delayed ACK */
530 #define	TCPCTL_V6MSSDFLT	13	/* MSS default for IPv6 */
531 #define	TCPCTL_SACK		14	/* Selective Acknowledgement,rfc 2018 */
532 #define	TCPCTL_DROP		15	/* drop tcp connection */
533 #define	TCPCTL_MAXID		16
534 #define TCPCTL_FINWAIT2_TIMEOUT        17
535 
536 #define TCPCTL_NAMES { \
537 	{ 0, 0 }, \
538 	{ "rfc1323", CTLTYPE_INT }, \
539 	{ "mssdflt", CTLTYPE_INT }, \
540 	{ "stats", CTLTYPE_STRUCT }, \
541 	{ "rttdflt", CTLTYPE_INT }, \
542 	{ "keepidle", CTLTYPE_INT }, \
543 	{ "keepintvl", CTLTYPE_INT }, \
544 	{ "sendspace", CTLTYPE_INT }, \
545 	{ "recvspace", CTLTYPE_INT }, \
546 	{ "keepinit", CTLTYPE_INT }, \
547 	{ "pcblist", CTLTYPE_STRUCT }, \
548 	{ "delacktime", CTLTYPE_INT }, \
549 	{ "v6mssdflt", CTLTYPE_INT }, \
550 	{ "maxid", CTLTYPE_INT }, \
551 }
552 
553 
554 #ifdef _KERNEL
555 #ifdef SYSCTL_DECL
556 SYSCTL_DECL(_net_inet_tcp);
557 SYSCTL_DECL(_net_inet_tcp_sack);
558 MALLOC_DECLARE(M_TCPLOG);
559 #endif
560 
561 VNET_DECLARE(struct inpcbhead, tcb);		/* queue of active tcpcb's */
562 VNET_DECLARE(struct inpcbinfo, tcbinfo);
563 VNET_DECLARE(struct tcpstat, tcpstat);		/* tcp statistics */
564 extern	int tcp_log_in_vain;
565 VNET_DECLARE(int, tcp_mssdflt);	/* XXX */
566 VNET_DECLARE(int, tcp_minmss);
567 VNET_DECLARE(int, tcp_delack_enabled);
568 VNET_DECLARE(int, tcp_do_newreno);
569 VNET_DECLARE(int, path_mtu_discovery);
570 VNET_DECLARE(int, ss_fltsz);
571 VNET_DECLARE(int, ss_fltsz_local);
572 #define	V_tcb			VNET(tcb)
573 #define	V_tcbinfo		VNET(tcbinfo)
574 #define	V_tcpstat		VNET(tcpstat)
575 #define	V_tcp_mssdflt		VNET(tcp_mssdflt)
576 #define	V_tcp_minmss		VNET(tcp_minmss)
577 #define	V_tcp_delack_enabled	VNET(tcp_delack_enabled)
578 #define	V_tcp_do_newreno	VNET(tcp_do_newreno)
579 #define	V_path_mtu_discovery	VNET(path_mtu_discovery)
580 #define	V_ss_fltsz		VNET(ss_fltsz)
581 #define	V_ss_fltsz_local	VNET(ss_fltsz_local)
582 
583 VNET_DECLARE(int, tcp_do_sack);			/* SACK enabled/disabled */
584 VNET_DECLARE(int, tcp_sc_rst_sock_fail);	/* RST on sock alloc failure */
585 #define	V_tcp_do_sack		VNET(tcp_do_sack)
586 #define	V_tcp_sc_rst_sock_fail	VNET(tcp_sc_rst_sock_fail)
587 
588 VNET_DECLARE(int, tcp_do_ecn);			/* TCP ECN enabled/disabled */
589 VNET_DECLARE(int, tcp_ecn_maxretries);
590 #define	V_tcp_do_ecn		VNET(tcp_do_ecn)
591 #define	V_tcp_ecn_maxretries	VNET(tcp_ecn_maxretries)
592 
593 int	 tcp_addoptions(struct tcpopt *, u_char *);
594 struct tcpcb *
595 	 tcp_close(struct tcpcb *);
596 void	 tcp_discardcb(struct tcpcb *);
597 void	 tcp_twstart(struct tcpcb *);
598 #if 0
599 int	 tcp_twrecycleable(struct tcptw *tw);
600 #endif
601 void	 tcp_twclose(struct tcptw *_tw, int _reuse);
602 void	 tcp_ctlinput(int, struct sockaddr *, void *);
603 int	 tcp_ctloutput(struct socket *, struct sockopt *);
604 struct tcpcb *
605 	 tcp_drop(struct tcpcb *, int);
606 void	 tcp_drain(void);
607 void	 tcp_init(void);
608 #ifdef VIMAGE
609 void	 tcp_destroy(void);
610 #endif
611 void	 tcp_fini(void *);
612 char 	*tcp_log_addrs(struct in_conninfo *, struct tcphdr *, void *,
613 	    const void *);
614 int	 tcp_reass(struct tcpcb *, struct tcphdr *, int *, struct mbuf *);
615 void	 tcp_reass_init(void);
616 #ifdef VIMAGE
617 void	 tcp_reass_destroy(void);
618 #endif
619 void	 tcp_input(struct mbuf *, int);
620 u_long	 tcp_maxmtu(struct in_conninfo *, int *);
621 u_long	 tcp_maxmtu6(struct in_conninfo *, int *);
622 void	 tcp_mss_update(struct tcpcb *, int, struct hc_metrics_lite *, int *);
623 void	 tcp_mss(struct tcpcb *, int);
624 int	 tcp_mssopt(struct in_conninfo *);
625 struct inpcb *
626 	 tcp_drop_syn_sent(struct inpcb *, int);
627 struct inpcb *
628 	 tcp_mtudisc(struct inpcb *, int);
629 struct tcpcb *
630 	 tcp_newtcpcb(struct inpcb *);
631 int	 tcp_output(struct tcpcb *);
632 void	 tcp_respond(struct tcpcb *, void *,
633 	    struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
634 void	 tcp_tw_init(void);
635 #ifdef VIMAGE
636 void	 tcp_tw_destroy(void);
637 #endif
638 void	 tcp_tw_zone_change(void);
639 int	 tcp_twcheck(struct inpcb *, struct tcpopt *, struct tcphdr *,
640 	    struct mbuf *, int);
641 int	 tcp_twrespond(struct tcptw *, int);
642 void	 tcp_setpersist(struct tcpcb *);
643 #ifdef TCP_SIGNATURE
644 int	 tcp_signature_compute(struct mbuf *, int, int, int, u_char *, u_int);
645 #endif
646 void	 tcp_slowtimo(void);
647 struct tcptemp *
648 	 tcpip_maketemplate(struct inpcb *);
649 void	 tcpip_fillheaders(struct inpcb *, void *, void *);
650 void	 tcp_timer_activate(struct tcpcb *, int, u_int);
651 int	 tcp_timer_active(struct tcpcb *, int);
652 void	 tcp_trace(short, short, struct tcpcb *, void *, struct tcphdr *, int);
653 void	 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq);
654 /*
655  * All tcp_hc_* functions are IPv4 and IPv6 (via in_conninfo)
656  */
657 void	 tcp_hc_init(void);
658 #ifdef VIMAGE
659 void	 tcp_hc_destroy(void);
660 #endif
661 void	 tcp_hc_get(struct in_conninfo *, struct hc_metrics_lite *);
662 u_long	 tcp_hc_getmtu(struct in_conninfo *);
663 void	 tcp_hc_updatemtu(struct in_conninfo *, u_long);
664 void	 tcp_hc_update(struct in_conninfo *, struct hc_metrics_lite *);
665 
666 extern	struct pr_usrreqs tcp_usrreqs;
667 extern	u_long tcp_sendspace;
668 extern	u_long tcp_recvspace;
669 tcp_seq tcp_new_isn(struct tcpcb *);
670 
671 void	 tcp_sack_doack(struct tcpcb *, struct tcpopt *, tcp_seq);
672 void	 tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_laststart, tcp_seq rcv_lastend);
673 void	 tcp_clean_sackreport(struct tcpcb *tp);
674 void	 tcp_sack_adjust(struct tcpcb *tp);
675 struct sackhole *tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt);
676 void	 tcp_sack_partialack(struct tcpcb *, struct tcphdr *);
677 void	 tcp_free_sackholes(struct tcpcb *tp);
678 int	 tcp_newreno(struct tcpcb *, struct tcphdr *);
679 u_long	 tcp_seq_subtract(u_long, u_long );
680 
681 #endif /* _KERNEL */
682 
683 #endif /* _NETINET_TCP_VAR_H_ */
684