1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/rcupdate.h>
3 #include <linux/spinlock.h>
4 #include <linux/jiffies.h>
5 #include <linux/module.h>
6 #include <linux/cache.h>
7 #include <linux/slab.h>
8 #include <linux/init.h>
9 #include <linux/tcp.h>
10 #include <linux/hash.h>
11 #include <linux/tcp_metrics.h>
12 #include <linux/vmalloc.h>
13
14 #include <net/inet_connection_sock.h>
15 #include <net/net_namespace.h>
16 #include <net/request_sock.h>
17 #include <net/inetpeer.h>
18 #include <net/sock.h>
19 #include <net/ipv6.h>
20 #include <net/dst.h>
21 #include <net/tcp.h>
22 #include <net/genetlink.h>
23
24 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr,
25 const struct inetpeer_addr *daddr,
26 struct net *net, unsigned int hash);
27
28 struct tcp_fastopen_metrics {
29 u16 mss;
30 u16 syn_loss:10, /* Recurring Fast Open SYN losses */
31 try_exp:2; /* Request w/ exp. option (once) */
32 unsigned long last_syn_loss; /* Last Fast Open SYN loss */
33 struct tcp_fastopen_cookie cookie;
34 };
35
36 /* TCP_METRIC_MAX includes 2 extra fields for userspace compatibility
37 * Kernel only stores RTT and RTTVAR in usec resolution
38 */
39 #define TCP_METRIC_MAX_KERNEL (TCP_METRIC_MAX - 2)
40
41 struct tcp_metrics_block {
42 struct tcp_metrics_block __rcu *tcpm_next;
43 struct net *tcpm_net;
44 struct inetpeer_addr tcpm_saddr;
45 struct inetpeer_addr tcpm_daddr;
46 unsigned long tcpm_stamp;
47 u32 tcpm_lock;
48 u32 tcpm_vals[TCP_METRIC_MAX_KERNEL + 1];
49 struct tcp_fastopen_metrics tcpm_fastopen;
50
51 struct rcu_head rcu_head;
52 };
53
tm_net(const struct tcp_metrics_block * tm)54 static inline struct net *tm_net(const struct tcp_metrics_block *tm)
55 {
56 /* Paired with the WRITE_ONCE() in tcpm_new() */
57 return READ_ONCE(tm->tcpm_net);
58 }
59
tcp_metric_locked(struct tcp_metrics_block * tm,enum tcp_metric_index idx)60 static bool tcp_metric_locked(struct tcp_metrics_block *tm,
61 enum tcp_metric_index idx)
62 {
63 /* Paired with WRITE_ONCE() in tcpm_suck_dst() */
64 return READ_ONCE(tm->tcpm_lock) & (1 << idx);
65 }
66
tcp_metric_get(const struct tcp_metrics_block * tm,enum tcp_metric_index idx)67 static u32 tcp_metric_get(const struct tcp_metrics_block *tm,
68 enum tcp_metric_index idx)
69 {
70 /* Paired with WRITE_ONCE() in tcp_metric_set() */
71 return READ_ONCE(tm->tcpm_vals[idx]);
72 }
73
tcp_metric_set(struct tcp_metrics_block * tm,enum tcp_metric_index idx,u32 val)74 static void tcp_metric_set(struct tcp_metrics_block *tm,
75 enum tcp_metric_index idx,
76 u32 val)
77 {
78 /* Paired with READ_ONCE() in tcp_metric_get() */
79 WRITE_ONCE(tm->tcpm_vals[idx], val);
80 }
81
addr_same(const struct inetpeer_addr * a,const struct inetpeer_addr * b)82 static bool addr_same(const struct inetpeer_addr *a,
83 const struct inetpeer_addr *b)
84 {
85 return (a->family == b->family) && !inetpeer_addr_cmp(a, b);
86 }
87
88 struct tcpm_hash_bucket {
89 struct tcp_metrics_block __rcu *chain;
90 };
91
92 static struct tcpm_hash_bucket *tcp_metrics_hash __read_mostly;
93 static unsigned int tcp_metrics_hash_log __read_mostly;
94
95 static DEFINE_SPINLOCK(tcp_metrics_lock);
96 static DEFINE_SEQLOCK(fastopen_seqlock);
97
tcpm_suck_dst(struct tcp_metrics_block * tm,const struct dst_entry * dst,bool fastopen_clear)98 static void tcpm_suck_dst(struct tcp_metrics_block *tm,
99 const struct dst_entry *dst,
100 bool fastopen_clear)
101 {
102 u32 msval;
103 u32 val;
104
105 WRITE_ONCE(tm->tcpm_stamp, jiffies);
106
107 val = 0;
108 if (dst_metric_locked(dst, RTAX_RTT))
109 val |= 1 << TCP_METRIC_RTT;
110 if (dst_metric_locked(dst, RTAX_RTTVAR))
111 val |= 1 << TCP_METRIC_RTTVAR;
112 if (dst_metric_locked(dst, RTAX_SSTHRESH))
113 val |= 1 << TCP_METRIC_SSTHRESH;
114 if (dst_metric_locked(dst, RTAX_CWND))
115 val |= 1 << TCP_METRIC_CWND;
116 if (dst_metric_locked(dst, RTAX_REORDERING))
117 val |= 1 << TCP_METRIC_REORDERING;
118 /* Paired with READ_ONCE() in tcp_metric_locked() */
119 WRITE_ONCE(tm->tcpm_lock, val);
120
121 msval = dst_metric_raw(dst, RTAX_RTT);
122 tcp_metric_set(tm, TCP_METRIC_RTT, msval * USEC_PER_MSEC);
123
124 msval = dst_metric_raw(dst, RTAX_RTTVAR);
125 tcp_metric_set(tm, TCP_METRIC_RTTVAR, msval * USEC_PER_MSEC);
126 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
127 dst_metric_raw(dst, RTAX_SSTHRESH));
128 tcp_metric_set(tm, TCP_METRIC_CWND,
129 dst_metric_raw(dst, RTAX_CWND));
130 tcp_metric_set(tm, TCP_METRIC_REORDERING,
131 dst_metric_raw(dst, RTAX_REORDERING));
132 if (fastopen_clear) {
133 write_seqlock(&fastopen_seqlock);
134 tm->tcpm_fastopen.mss = 0;
135 tm->tcpm_fastopen.syn_loss = 0;
136 tm->tcpm_fastopen.try_exp = 0;
137 tm->tcpm_fastopen.cookie.exp = false;
138 tm->tcpm_fastopen.cookie.len = 0;
139 write_sequnlock(&fastopen_seqlock);
140 }
141 }
142
143 #define TCP_METRICS_TIMEOUT (60 * 60 * HZ)
144
tcpm_check_stamp(struct tcp_metrics_block * tm,const struct dst_entry * dst)145 static void tcpm_check_stamp(struct tcp_metrics_block *tm,
146 const struct dst_entry *dst)
147 {
148 unsigned long limit;
149
150 if (!tm)
151 return;
152 limit = READ_ONCE(tm->tcpm_stamp) + TCP_METRICS_TIMEOUT;
153 if (unlikely(time_after(jiffies, limit)))
154 tcpm_suck_dst(tm, dst, false);
155 }
156
157 #define TCP_METRICS_RECLAIM_DEPTH 5
158 #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL
159
160 #define deref_locked(p) \
161 rcu_dereference_protected(p, lockdep_is_held(&tcp_metrics_lock))
162
tcpm_new(struct dst_entry * dst,struct inetpeer_addr * saddr,struct inetpeer_addr * daddr,unsigned int hash)163 static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
164 struct inetpeer_addr *saddr,
165 struct inetpeer_addr *daddr,
166 unsigned int hash)
167 {
168 struct tcp_metrics_block *tm;
169 struct net *net;
170 bool reclaim = false;
171
172 spin_lock_bh(&tcp_metrics_lock);
173 net = dev_net(dst->dev);
174
175 /* While waiting for the spin-lock the cache might have been populated
176 * with this entry and so we have to check again.
177 */
178 tm = __tcp_get_metrics(saddr, daddr, net, hash);
179 if (tm == TCP_METRICS_RECLAIM_PTR) {
180 reclaim = true;
181 tm = NULL;
182 }
183 if (tm) {
184 tcpm_check_stamp(tm, dst);
185 goto out_unlock;
186 }
187
188 if (unlikely(reclaim)) {
189 struct tcp_metrics_block *oldest;
190
191 oldest = deref_locked(tcp_metrics_hash[hash].chain);
192 for (tm = deref_locked(oldest->tcpm_next); tm;
193 tm = deref_locked(tm->tcpm_next)) {
194 if (time_before(READ_ONCE(tm->tcpm_stamp),
195 READ_ONCE(oldest->tcpm_stamp)))
196 oldest = tm;
197 }
198 tm = oldest;
199 } else {
200 tm = kzalloc(sizeof(*tm), GFP_ATOMIC);
201 if (!tm)
202 goto out_unlock;
203 }
204 /* Paired with the READ_ONCE() in tm_net() */
205 WRITE_ONCE(tm->tcpm_net, net);
206
207 tm->tcpm_saddr = *saddr;
208 tm->tcpm_daddr = *daddr;
209
210 tcpm_suck_dst(tm, dst, reclaim);
211
212 if (likely(!reclaim)) {
213 tm->tcpm_next = tcp_metrics_hash[hash].chain;
214 rcu_assign_pointer(tcp_metrics_hash[hash].chain, tm);
215 }
216
217 out_unlock:
218 spin_unlock_bh(&tcp_metrics_lock);
219 return tm;
220 }
221
tcp_get_encode(struct tcp_metrics_block * tm,int depth)222 static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth)
223 {
224 if (tm)
225 return tm;
226 if (depth > TCP_METRICS_RECLAIM_DEPTH)
227 return TCP_METRICS_RECLAIM_PTR;
228 return NULL;
229 }
230
__tcp_get_metrics(const struct inetpeer_addr * saddr,const struct inetpeer_addr * daddr,struct net * net,unsigned int hash)231 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr,
232 const struct inetpeer_addr *daddr,
233 struct net *net, unsigned int hash)
234 {
235 struct tcp_metrics_block *tm;
236 int depth = 0;
237
238 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
239 tm = rcu_dereference(tm->tcpm_next)) {
240 if (addr_same(&tm->tcpm_saddr, saddr) &&
241 addr_same(&tm->tcpm_daddr, daddr) &&
242 net_eq(tm_net(tm), net))
243 break;
244 depth++;
245 }
246 return tcp_get_encode(tm, depth);
247 }
248
__tcp_get_metrics_req(struct request_sock * req,struct dst_entry * dst)249 static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
250 struct dst_entry *dst)
251 {
252 struct tcp_metrics_block *tm;
253 struct inetpeer_addr saddr, daddr;
254 unsigned int hash;
255 struct net *net;
256
257 saddr.family = req->rsk_ops->family;
258 daddr.family = req->rsk_ops->family;
259 switch (daddr.family) {
260 case AF_INET:
261 inetpeer_set_addr_v4(&saddr, inet_rsk(req)->ir_loc_addr);
262 inetpeer_set_addr_v4(&daddr, inet_rsk(req)->ir_rmt_addr);
263 hash = ipv4_addr_hash(inet_rsk(req)->ir_rmt_addr);
264 break;
265 #if IS_ENABLED(CONFIG_IPV6)
266 case AF_INET6:
267 inetpeer_set_addr_v6(&saddr, &inet_rsk(req)->ir_v6_loc_addr);
268 inetpeer_set_addr_v6(&daddr, &inet_rsk(req)->ir_v6_rmt_addr);
269 hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr);
270 break;
271 #endif
272 default:
273 return NULL;
274 }
275
276 net = dev_net(dst->dev);
277 hash ^= net_hash_mix(net);
278 hash = hash_32(hash, tcp_metrics_hash_log);
279
280 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
281 tm = rcu_dereference(tm->tcpm_next)) {
282 if (addr_same(&tm->tcpm_saddr, &saddr) &&
283 addr_same(&tm->tcpm_daddr, &daddr) &&
284 net_eq(tm_net(tm), net))
285 break;
286 }
287 tcpm_check_stamp(tm, dst);
288 return tm;
289 }
290
tcp_get_metrics(struct sock * sk,struct dst_entry * dst,bool create)291 static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk,
292 struct dst_entry *dst,
293 bool create)
294 {
295 struct tcp_metrics_block *tm;
296 struct inetpeer_addr saddr, daddr;
297 unsigned int hash;
298 struct net *net;
299
300 if (sk->sk_family == AF_INET) {
301 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr);
302 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr);
303 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr);
304 }
305 #if IS_ENABLED(CONFIG_IPV6)
306 else if (sk->sk_family == AF_INET6) {
307 if (ipv6_addr_v4mapped(&sk->sk_v6_daddr)) {
308 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr);
309 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr);
310 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr);
311 } else {
312 inetpeer_set_addr_v6(&saddr, &sk->sk_v6_rcv_saddr);
313 inetpeer_set_addr_v6(&daddr, &sk->sk_v6_daddr);
314 hash = ipv6_addr_hash(&sk->sk_v6_daddr);
315 }
316 }
317 #endif
318 else
319 return NULL;
320
321 net = dev_net(dst->dev);
322 hash ^= net_hash_mix(net);
323 hash = hash_32(hash, tcp_metrics_hash_log);
324
325 tm = __tcp_get_metrics(&saddr, &daddr, net, hash);
326 if (tm == TCP_METRICS_RECLAIM_PTR)
327 tm = NULL;
328 if (!tm && create)
329 tm = tcpm_new(dst, &saddr, &daddr, hash);
330 else
331 tcpm_check_stamp(tm, dst);
332
333 return tm;
334 }
335
336 /* Save metrics learned by this TCP session. This function is called
337 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT
338 * or goes from LAST-ACK to CLOSE.
339 */
tcp_update_metrics(struct sock * sk)340 void tcp_update_metrics(struct sock *sk)
341 {
342 const struct inet_connection_sock *icsk = inet_csk(sk);
343 struct dst_entry *dst = __sk_dst_get(sk);
344 struct tcp_sock *tp = tcp_sk(sk);
345 struct net *net = sock_net(sk);
346 struct tcp_metrics_block *tm;
347 unsigned long rtt;
348 u32 val;
349 int m;
350
351 sk_dst_confirm(sk);
352 if (READ_ONCE(net->ipv4.sysctl_tcp_nometrics_save) || !dst)
353 return;
354
355 rcu_read_lock();
356 if (icsk->icsk_backoff || !tp->srtt_us) {
357 /* This session failed to estimate rtt. Why?
358 * Probably, no packets returned in time. Reset our
359 * results.
360 */
361 tm = tcp_get_metrics(sk, dst, false);
362 if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT))
363 tcp_metric_set(tm, TCP_METRIC_RTT, 0);
364 goto out_unlock;
365 } else
366 tm = tcp_get_metrics(sk, dst, true);
367
368 if (!tm)
369 goto out_unlock;
370
371 rtt = tcp_metric_get(tm, TCP_METRIC_RTT);
372 m = rtt - tp->srtt_us;
373
374 /* If newly calculated rtt larger than stored one, store new
375 * one. Otherwise, use EWMA. Remember, rtt overestimation is
376 * always better than underestimation.
377 */
378 if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) {
379 if (m <= 0)
380 rtt = tp->srtt_us;
381 else
382 rtt -= (m >> 3);
383 tcp_metric_set(tm, TCP_METRIC_RTT, rtt);
384 }
385
386 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) {
387 unsigned long var;
388
389 if (m < 0)
390 m = -m;
391
392 /* Scale deviation to rttvar fixed point */
393 m >>= 1;
394 if (m < tp->mdev_us)
395 m = tp->mdev_us;
396
397 var = tcp_metric_get(tm, TCP_METRIC_RTTVAR);
398 if (m >= var)
399 var = m;
400 else
401 var -= (var - m) >> 2;
402
403 tcp_metric_set(tm, TCP_METRIC_RTTVAR, var);
404 }
405
406 if (tcp_in_initial_slowstart(tp)) {
407 /* Slow start still did not finish. */
408 if (!READ_ONCE(net->ipv4.sysctl_tcp_no_ssthresh_metrics_save) &&
409 !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
410 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
411 if (val && (tcp_snd_cwnd(tp) >> 1) > val)
412 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
413 tcp_snd_cwnd(tp) >> 1);
414 }
415 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
416 val = tcp_metric_get(tm, TCP_METRIC_CWND);
417 if (tcp_snd_cwnd(tp) > val)
418 tcp_metric_set(tm, TCP_METRIC_CWND,
419 tcp_snd_cwnd(tp));
420 }
421 } else if (!tcp_in_slow_start(tp) &&
422 icsk->icsk_ca_state == TCP_CA_Open) {
423 /* Cong. avoidance phase, cwnd is reliable. */
424 if (!READ_ONCE(net->ipv4.sysctl_tcp_no_ssthresh_metrics_save) &&
425 !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH))
426 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
427 max(tcp_snd_cwnd(tp) >> 1, tp->snd_ssthresh));
428 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
429 val = tcp_metric_get(tm, TCP_METRIC_CWND);
430 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tcp_snd_cwnd(tp)) >> 1);
431 }
432 } else {
433 /* Else slow start did not finish, cwnd is non-sense,
434 * ssthresh may be also invalid.
435 */
436 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
437 val = tcp_metric_get(tm, TCP_METRIC_CWND);
438 tcp_metric_set(tm, TCP_METRIC_CWND,
439 (val + tp->snd_ssthresh) >> 1);
440 }
441 if (!READ_ONCE(net->ipv4.sysctl_tcp_no_ssthresh_metrics_save) &&
442 !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
443 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
444 if (val && tp->snd_ssthresh > val)
445 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
446 tp->snd_ssthresh);
447 }
448 if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) {
449 val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
450 if (val < tp->reordering &&
451 tp->reordering !=
452 READ_ONCE(net->ipv4.sysctl_tcp_reordering))
453 tcp_metric_set(tm, TCP_METRIC_REORDERING,
454 tp->reordering);
455 }
456 }
457 WRITE_ONCE(tm->tcpm_stamp, jiffies);
458 out_unlock:
459 rcu_read_unlock();
460 }
461
462 /* Initialize metrics on socket. */
463
tcp_init_metrics(struct sock * sk)464 void tcp_init_metrics(struct sock *sk)
465 {
466 struct dst_entry *dst = __sk_dst_get(sk);
467 struct tcp_sock *tp = tcp_sk(sk);
468 struct net *net = sock_net(sk);
469 struct tcp_metrics_block *tm;
470 u32 val, crtt = 0; /* cached RTT scaled by 8 */
471
472 sk_dst_confirm(sk);
473 /* ssthresh may have been reduced unnecessarily during.
474 * 3WHS. Restore it back to its initial default.
475 */
476 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
477 if (!dst)
478 goto reset;
479
480 rcu_read_lock();
481 tm = tcp_get_metrics(sk, dst, false);
482 if (!tm) {
483 rcu_read_unlock();
484 goto reset;
485 }
486
487 if (tcp_metric_locked(tm, TCP_METRIC_CWND))
488 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND);
489
490 val = READ_ONCE(net->ipv4.sysctl_tcp_no_ssthresh_metrics_save) ?
491 0 : tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
492 if (val) {
493 tp->snd_ssthresh = val;
494 if (tp->snd_ssthresh > tp->snd_cwnd_clamp)
495 tp->snd_ssthresh = tp->snd_cwnd_clamp;
496 }
497 val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
498 if (val && tp->reordering != val)
499 tp->reordering = val;
500
501 crtt = tcp_metric_get(tm, TCP_METRIC_RTT);
502 rcu_read_unlock();
503 reset:
504 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal
505 * to seed the RTO for later data packets because SYN packets are
506 * small. Use the per-dst cached values to seed the RTO but keep
507 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar).
508 * Later the RTO will be updated immediately upon obtaining the first
509 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only
510 * influences the first RTO but not later RTT estimation.
511 *
512 * But if RTT is not available from the SYN (due to retransmits or
513 * syn cookies) or the cache, force a conservative 3secs timeout.
514 *
515 * A bit of theory. RTT is time passed after "normal" sized packet
516 * is sent until it is ACKed. In normal circumstances sending small
517 * packets force peer to delay ACKs and calculation is correct too.
518 * The algorithm is adaptive and, provided we follow specs, it
519 * NEVER underestimate RTT. BUT! If peer tries to make some clever
520 * tricks sort of "quick acks" for time long enough to decrease RTT
521 * to low value, and then abruptly stops to do it and starts to delay
522 * ACKs, wait for troubles.
523 */
524 if (crtt > tp->srtt_us) {
525 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */
526 crtt /= 8 * USEC_PER_SEC / HZ;
527 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk));
528 } else if (tp->srtt_us == 0) {
529 /* RFC6298: 5.7 We've failed to get a valid RTT sample from
530 * 3WHS. This is most likely due to retransmission,
531 * including spurious one. Reset the RTO back to 3secs
532 * from the more aggressive 1sec to avoid more spurious
533 * retransmission.
534 */
535 tp->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK);
536 tp->mdev_us = tp->mdev_max_us = tp->rttvar_us;
537
538 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK;
539 }
540 }
541
tcp_peer_is_proven(struct request_sock * req,struct dst_entry * dst)542 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst)
543 {
544 struct tcp_metrics_block *tm;
545 bool ret;
546
547 if (!dst)
548 return false;
549
550 rcu_read_lock();
551 tm = __tcp_get_metrics_req(req, dst);
552 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT))
553 ret = true;
554 else
555 ret = false;
556 rcu_read_unlock();
557
558 return ret;
559 }
560
tcp_fastopen_cache_get(struct sock * sk,u16 * mss,struct tcp_fastopen_cookie * cookie)561 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
562 struct tcp_fastopen_cookie *cookie)
563 {
564 struct tcp_metrics_block *tm;
565
566 rcu_read_lock();
567 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false);
568 if (tm) {
569 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
570 unsigned int seq;
571
572 do {
573 seq = read_seqbegin(&fastopen_seqlock);
574 if (tfom->mss)
575 *mss = tfom->mss;
576 *cookie = tfom->cookie;
577 if (cookie->len <= 0 && tfom->try_exp == 1)
578 cookie->exp = true;
579 } while (read_seqretry(&fastopen_seqlock, seq));
580 }
581 rcu_read_unlock();
582 }
583
tcp_fastopen_cache_set(struct sock * sk,u16 mss,struct tcp_fastopen_cookie * cookie,bool syn_lost,u16 try_exp)584 void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
585 struct tcp_fastopen_cookie *cookie, bool syn_lost,
586 u16 try_exp)
587 {
588 struct dst_entry *dst = __sk_dst_get(sk);
589 struct tcp_metrics_block *tm;
590
591 if (!dst)
592 return;
593 rcu_read_lock();
594 tm = tcp_get_metrics(sk, dst, true);
595 if (tm) {
596 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
597
598 write_seqlock_bh(&fastopen_seqlock);
599 if (mss)
600 tfom->mss = mss;
601 if (cookie && cookie->len > 0)
602 tfom->cookie = *cookie;
603 else if (try_exp > tfom->try_exp &&
604 tfom->cookie.len <= 0 && !tfom->cookie.exp)
605 tfom->try_exp = try_exp;
606 if (syn_lost) {
607 ++tfom->syn_loss;
608 tfom->last_syn_loss = jiffies;
609 } else
610 tfom->syn_loss = 0;
611 write_sequnlock_bh(&fastopen_seqlock);
612 }
613 rcu_read_unlock();
614 }
615
616 static struct genl_family tcp_metrics_nl_family;
617
618 static const struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = {
619 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, },
620 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY,
621 .len = sizeof(struct in6_addr), },
622 /* Following attributes are not received for GET/DEL,
623 * we keep them for reference
624 */
625 #if 0
626 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, },
627 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, },
628 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, },
629 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, },
630 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, },
631 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, },
632 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, },
633 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY,
634 .len = TCP_FASTOPEN_COOKIE_MAX, },
635 #endif
636 };
637
638 /* Add attributes, caller cancels its header on failure */
tcp_metrics_fill_info(struct sk_buff * msg,struct tcp_metrics_block * tm)639 static int tcp_metrics_fill_info(struct sk_buff *msg,
640 struct tcp_metrics_block *tm)
641 {
642 struct nlattr *nest;
643 int i;
644
645 switch (tm->tcpm_daddr.family) {
646 case AF_INET:
647 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_ADDR_IPV4,
648 inetpeer_get_addr_v4(&tm->tcpm_daddr)) < 0)
649 goto nla_put_failure;
650 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_SADDR_IPV4,
651 inetpeer_get_addr_v4(&tm->tcpm_saddr)) < 0)
652 goto nla_put_failure;
653 break;
654 case AF_INET6:
655 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_ADDR_IPV6,
656 inetpeer_get_addr_v6(&tm->tcpm_daddr)) < 0)
657 goto nla_put_failure;
658 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_SADDR_IPV6,
659 inetpeer_get_addr_v6(&tm->tcpm_saddr)) < 0)
660 goto nla_put_failure;
661 break;
662 default:
663 return -EAFNOSUPPORT;
664 }
665
666 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE,
667 jiffies - READ_ONCE(tm->tcpm_stamp),
668 TCP_METRICS_ATTR_PAD) < 0)
669 goto nla_put_failure;
670
671 {
672 int n = 0;
673
674 nest = nla_nest_start_noflag(msg, TCP_METRICS_ATTR_VALS);
675 if (!nest)
676 goto nla_put_failure;
677 for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) {
678 u32 val = tcp_metric_get(tm, i);
679
680 if (!val)
681 continue;
682 if (i == TCP_METRIC_RTT) {
683 if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1,
684 val) < 0)
685 goto nla_put_failure;
686 n++;
687 val = max(val / 1000, 1U);
688 }
689 if (i == TCP_METRIC_RTTVAR) {
690 if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1,
691 val) < 0)
692 goto nla_put_failure;
693 n++;
694 val = max(val / 1000, 1U);
695 }
696 if (nla_put_u32(msg, i + 1, val) < 0)
697 goto nla_put_failure;
698 n++;
699 }
700 if (n)
701 nla_nest_end(msg, nest);
702 else
703 nla_nest_cancel(msg, nest);
704 }
705
706 {
707 struct tcp_fastopen_metrics tfom_copy[1], *tfom;
708 unsigned int seq;
709
710 do {
711 seq = read_seqbegin(&fastopen_seqlock);
712 tfom_copy[0] = tm->tcpm_fastopen;
713 } while (read_seqretry(&fastopen_seqlock, seq));
714
715 tfom = tfom_copy;
716 if (tfom->mss &&
717 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS,
718 tfom->mss) < 0)
719 goto nla_put_failure;
720 if (tfom->syn_loss &&
721 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS,
722 tfom->syn_loss) < 0 ||
723 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS,
724 jiffies - tfom->last_syn_loss,
725 TCP_METRICS_ATTR_PAD) < 0))
726 goto nla_put_failure;
727 if (tfom->cookie.len > 0 &&
728 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE,
729 tfom->cookie.len, tfom->cookie.val) < 0)
730 goto nla_put_failure;
731 }
732
733 return 0;
734
735 nla_put_failure:
736 return -EMSGSIZE;
737 }
738
tcp_metrics_dump_info(struct sk_buff * skb,struct netlink_callback * cb,struct tcp_metrics_block * tm)739 static int tcp_metrics_dump_info(struct sk_buff *skb,
740 struct netlink_callback *cb,
741 struct tcp_metrics_block *tm)
742 {
743 void *hdr;
744
745 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
746 &tcp_metrics_nl_family, NLM_F_MULTI,
747 TCP_METRICS_CMD_GET);
748 if (!hdr)
749 return -EMSGSIZE;
750
751 if (tcp_metrics_fill_info(skb, tm) < 0)
752 goto nla_put_failure;
753
754 genlmsg_end(skb, hdr);
755 return 0;
756
757 nla_put_failure:
758 genlmsg_cancel(skb, hdr);
759 return -EMSGSIZE;
760 }
761
tcp_metrics_nl_dump(struct sk_buff * skb,struct netlink_callback * cb)762 static int tcp_metrics_nl_dump(struct sk_buff *skb,
763 struct netlink_callback *cb)
764 {
765 struct net *net = sock_net(skb->sk);
766 unsigned int max_rows = 1U << tcp_metrics_hash_log;
767 unsigned int row, s_row = cb->args[0];
768 int s_col = cb->args[1], col = s_col;
769 int res = 0;
770
771 for (row = s_row; row < max_rows; row++, s_col = 0) {
772 struct tcp_metrics_block *tm;
773 struct tcpm_hash_bucket *hb = tcp_metrics_hash + row;
774
775 rcu_read_lock();
776 for (col = 0, tm = rcu_dereference(hb->chain); tm;
777 tm = rcu_dereference(tm->tcpm_next), col++) {
778 if (!net_eq(tm_net(tm), net))
779 continue;
780 if (col < s_col)
781 continue;
782 res = tcp_metrics_dump_info(skb, cb, tm);
783 if (res < 0) {
784 rcu_read_unlock();
785 goto done;
786 }
787 }
788 rcu_read_unlock();
789 }
790
791 done:
792 cb->args[0] = row;
793 cb->args[1] = col;
794 return res;
795 }
796
__parse_nl_addr(struct genl_info * info,struct inetpeer_addr * addr,unsigned int * hash,int optional,int v4,int v6)797 static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
798 unsigned int *hash, int optional, int v4, int v6)
799 {
800 struct nlattr *a;
801
802 a = info->attrs[v4];
803 if (a) {
804 inetpeer_set_addr_v4(addr, nla_get_in_addr(a));
805 if (hash)
806 *hash = ipv4_addr_hash(inetpeer_get_addr_v4(addr));
807 return 0;
808 }
809 a = info->attrs[v6];
810 if (a) {
811 struct in6_addr in6;
812
813 if (nla_len(a) != sizeof(struct in6_addr))
814 return -EINVAL;
815 in6 = nla_get_in6_addr(a);
816 inetpeer_set_addr_v6(addr, &in6);
817 if (hash)
818 *hash = ipv6_addr_hash(inetpeer_get_addr_v6(addr));
819 return 0;
820 }
821 return optional ? 1 : -EAFNOSUPPORT;
822 }
823
parse_nl_addr(struct genl_info * info,struct inetpeer_addr * addr,unsigned int * hash,int optional)824 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
825 unsigned int *hash, int optional)
826 {
827 return __parse_nl_addr(info, addr, hash, optional,
828 TCP_METRICS_ATTR_ADDR_IPV4,
829 TCP_METRICS_ATTR_ADDR_IPV6);
830 }
831
parse_nl_saddr(struct genl_info * info,struct inetpeer_addr * addr)832 static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr)
833 {
834 return __parse_nl_addr(info, addr, NULL, 0,
835 TCP_METRICS_ATTR_SADDR_IPV4,
836 TCP_METRICS_ATTR_SADDR_IPV6);
837 }
838
tcp_metrics_nl_cmd_get(struct sk_buff * skb,struct genl_info * info)839 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
840 {
841 struct tcp_metrics_block *tm;
842 struct inetpeer_addr saddr, daddr;
843 unsigned int hash;
844 struct sk_buff *msg;
845 struct net *net = genl_info_net(info);
846 void *reply;
847 int ret;
848 bool src = true;
849
850 ret = parse_nl_addr(info, &daddr, &hash, 0);
851 if (ret < 0)
852 return ret;
853
854 ret = parse_nl_saddr(info, &saddr);
855 if (ret < 0)
856 src = false;
857
858 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
859 if (!msg)
860 return -ENOMEM;
861
862 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0,
863 info->genlhdr->cmd);
864 if (!reply)
865 goto nla_put_failure;
866
867 hash ^= net_hash_mix(net);
868 hash = hash_32(hash, tcp_metrics_hash_log);
869 ret = -ESRCH;
870 rcu_read_lock();
871 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
872 tm = rcu_dereference(tm->tcpm_next)) {
873 if (addr_same(&tm->tcpm_daddr, &daddr) &&
874 (!src || addr_same(&tm->tcpm_saddr, &saddr)) &&
875 net_eq(tm_net(tm), net)) {
876 ret = tcp_metrics_fill_info(msg, tm);
877 break;
878 }
879 }
880 rcu_read_unlock();
881 if (ret < 0)
882 goto out_free;
883
884 genlmsg_end(msg, reply);
885 return genlmsg_reply(msg, info);
886
887 nla_put_failure:
888 ret = -EMSGSIZE;
889
890 out_free:
891 nlmsg_free(msg);
892 return ret;
893 }
894
tcp_metrics_flush_all(struct net * net)895 static void tcp_metrics_flush_all(struct net *net)
896 {
897 unsigned int max_rows = 1U << tcp_metrics_hash_log;
898 struct tcpm_hash_bucket *hb = tcp_metrics_hash;
899 struct tcp_metrics_block *tm;
900 unsigned int row;
901
902 for (row = 0; row < max_rows; row++, hb++) {
903 struct tcp_metrics_block __rcu **pp = &hb->chain;
904 bool match;
905
906 if (!rcu_access_pointer(*pp))
907 continue;
908
909 spin_lock_bh(&tcp_metrics_lock);
910 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {
911 match = net ? net_eq(tm_net(tm), net) :
912 !refcount_read(&tm_net(tm)->ns.count);
913 if (match) {
914 rcu_assign_pointer(*pp, tm->tcpm_next);
915 kfree_rcu(tm, rcu_head);
916 } else {
917 pp = &tm->tcpm_next;
918 }
919 }
920 spin_unlock_bh(&tcp_metrics_lock);
921 cond_resched();
922 }
923 }
924
tcp_metrics_nl_cmd_del(struct sk_buff * skb,struct genl_info * info)925 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info)
926 {
927 struct tcpm_hash_bucket *hb;
928 struct tcp_metrics_block *tm;
929 struct tcp_metrics_block __rcu **pp;
930 struct inetpeer_addr saddr, daddr;
931 unsigned int hash;
932 struct net *net = genl_info_net(info);
933 int ret;
934 bool src = true, found = false;
935
936 ret = parse_nl_addr(info, &daddr, &hash, 1);
937 if (ret < 0)
938 return ret;
939 if (ret > 0) {
940 tcp_metrics_flush_all(net);
941 return 0;
942 }
943 ret = parse_nl_saddr(info, &saddr);
944 if (ret < 0)
945 src = false;
946
947 hash ^= net_hash_mix(net);
948 hash = hash_32(hash, tcp_metrics_hash_log);
949 hb = tcp_metrics_hash + hash;
950 pp = &hb->chain;
951 spin_lock_bh(&tcp_metrics_lock);
952 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {
953 if (addr_same(&tm->tcpm_daddr, &daddr) &&
954 (!src || addr_same(&tm->tcpm_saddr, &saddr)) &&
955 net_eq(tm_net(tm), net)) {
956 rcu_assign_pointer(*pp, tm->tcpm_next);
957 kfree_rcu(tm, rcu_head);
958 found = true;
959 } else {
960 pp = &tm->tcpm_next;
961 }
962 }
963 spin_unlock_bh(&tcp_metrics_lock);
964 if (!found)
965 return -ESRCH;
966 return 0;
967 }
968
969 static const struct genl_small_ops tcp_metrics_nl_ops[] = {
970 {
971 .cmd = TCP_METRICS_CMD_GET,
972 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
973 .doit = tcp_metrics_nl_cmd_get,
974 .dumpit = tcp_metrics_nl_dump,
975 },
976 {
977 .cmd = TCP_METRICS_CMD_DEL,
978 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
979 .doit = tcp_metrics_nl_cmd_del,
980 .flags = GENL_ADMIN_PERM,
981 },
982 };
983
984 static struct genl_family tcp_metrics_nl_family __ro_after_init = {
985 .hdrsize = 0,
986 .name = TCP_METRICS_GENL_NAME,
987 .version = TCP_METRICS_GENL_VERSION,
988 .maxattr = TCP_METRICS_ATTR_MAX,
989 .policy = tcp_metrics_nl_policy,
990 .netnsok = true,
991 .parallel_ops = true,
992 .module = THIS_MODULE,
993 .small_ops = tcp_metrics_nl_ops,
994 .n_small_ops = ARRAY_SIZE(tcp_metrics_nl_ops),
995 .resv_start_op = TCP_METRICS_CMD_DEL + 1,
996 };
997
998 static unsigned int tcpmhash_entries __initdata;
set_tcpmhash_entries(char * str)999 static int __init set_tcpmhash_entries(char *str)
1000 {
1001 ssize_t ret;
1002
1003 if (!str)
1004 return 0;
1005
1006 ret = kstrtouint(str, 0, &tcpmhash_entries);
1007 if (ret)
1008 return 0;
1009
1010 return 1;
1011 }
1012 __setup("tcpmhash_entries=", set_tcpmhash_entries);
1013
tcp_metrics_hash_alloc(void)1014 static void __init tcp_metrics_hash_alloc(void)
1015 {
1016 unsigned int slots = tcpmhash_entries;
1017 size_t size;
1018
1019 if (!slots) {
1020 if (totalram_pages() >= 128 * 1024)
1021 slots = 16 * 1024;
1022 else
1023 slots = 8 * 1024;
1024 }
1025
1026 tcp_metrics_hash_log = order_base_2(slots);
1027 size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log;
1028
1029 tcp_metrics_hash = kvzalloc(size, GFP_KERNEL);
1030 if (!tcp_metrics_hash)
1031 panic("Could not allocate the tcp_metrics hash table\n");
1032 }
1033
tcp_net_metrics_exit_batch(struct list_head * net_exit_list)1034 static void __net_exit tcp_net_metrics_exit_batch(struct list_head *net_exit_list)
1035 {
1036 tcp_metrics_flush_all(NULL);
1037 }
1038
1039 static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
1040 .exit_batch = tcp_net_metrics_exit_batch,
1041 };
1042
tcp_metrics_init(void)1043 void __init tcp_metrics_init(void)
1044 {
1045 int ret;
1046
1047 tcp_metrics_hash_alloc();
1048
1049 ret = register_pernet_subsys(&tcp_net_metrics_ops);
1050 if (ret < 0)
1051 panic("Could not register tcp_net_metrics_ops\n");
1052
1053 ret = genl_register_family(&tcp_metrics_nl_family);
1054 if (ret < 0)
1055 panic("Could not register tcp_metrics generic netlink\n");
1056 }
1057