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Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec...
[deliverable/linux.git] / net / ipv4 / tcp_metrics.c
1 #include <linux/rcupdate.h>
2 #include <linux/spinlock.h>
3 #include <linux/jiffies.h>
4 #include <linux/module.h>
5 #include <linux/cache.h>
6 #include <linux/slab.h>
7 #include <linux/init.h>
8 #include <linux/tcp.h>
9 #include <linux/hash.h>
10 #include <linux/tcp_metrics.h>
11 #include <linux/vmalloc.h>
12
13 #include <net/inet_connection_sock.h>
14 #include <net/net_namespace.h>
15 #include <net/request_sock.h>
16 #include <net/inetpeer.h>
17 #include <net/sock.h>
18 #include <net/ipv6.h>
19 #include <net/dst.h>
20 #include <net/tcp.h>
21 #include <net/genetlink.h>
22
23 int sysctl_tcp_nometrics_save __read_mostly;
24
25 struct tcp_fastopen_metrics {
26 u16 mss;
27 u16 syn_loss:10; /* Recurring Fast Open SYN losses */
28 unsigned long last_syn_loss; /* Last Fast Open SYN loss */
29 struct tcp_fastopen_cookie cookie;
30 };
31
32 struct tcp_metrics_block {
33 struct tcp_metrics_block __rcu *tcpm_next;
34 struct inetpeer_addr tcpm_addr;
35 unsigned long tcpm_stamp;
36 u32 tcpm_ts;
37 u32 tcpm_ts_stamp;
38 u32 tcpm_lock;
39 u32 tcpm_vals[TCP_METRIC_MAX + 1];
40 struct tcp_fastopen_metrics tcpm_fastopen;
41
42 struct rcu_head rcu_head;
43 };
44
45 static bool tcp_metric_locked(struct tcp_metrics_block *tm,
46 enum tcp_metric_index idx)
47 {
48 return tm->tcpm_lock & (1 << idx);
49 }
50
51 static u32 tcp_metric_get(struct tcp_metrics_block *tm,
52 enum tcp_metric_index idx)
53 {
54 return tm->tcpm_vals[idx];
55 }
56
57 static u32 tcp_metric_get_jiffies(struct tcp_metrics_block *tm,
58 enum tcp_metric_index idx)
59 {
60 return msecs_to_jiffies(tm->tcpm_vals[idx]);
61 }
62
63 static void tcp_metric_set(struct tcp_metrics_block *tm,
64 enum tcp_metric_index idx,
65 u32 val)
66 {
67 tm->tcpm_vals[idx] = val;
68 }
69
70 static void tcp_metric_set_msecs(struct tcp_metrics_block *tm,
71 enum tcp_metric_index idx,
72 u32 val)
73 {
74 tm->tcpm_vals[idx] = jiffies_to_msecs(val);
75 }
76
77 static bool addr_same(const struct inetpeer_addr *a,
78 const struct inetpeer_addr *b)
79 {
80 const struct in6_addr *a6, *b6;
81
82 if (a->family != b->family)
83 return false;
84 if (a->family == AF_INET)
85 return a->addr.a4 == b->addr.a4;
86
87 a6 = (const struct in6_addr *) &a->addr.a6[0];
88 b6 = (const struct in6_addr *) &b->addr.a6[0];
89
90 return ipv6_addr_equal(a6, b6);
91 }
92
93 struct tcpm_hash_bucket {
94 struct tcp_metrics_block __rcu *chain;
95 };
96
97 static DEFINE_SPINLOCK(tcp_metrics_lock);
98
99 static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst,
100 bool fastopen_clear)
101 {
102 u32 val;
103
104 tm->tcpm_stamp = jiffies;
105
106 val = 0;
107 if (dst_metric_locked(dst, RTAX_RTT))
108 val |= 1 << TCP_METRIC_RTT;
109 if (dst_metric_locked(dst, RTAX_RTTVAR))
110 val |= 1 << TCP_METRIC_RTTVAR;
111 if (dst_metric_locked(dst, RTAX_SSTHRESH))
112 val |= 1 << TCP_METRIC_SSTHRESH;
113 if (dst_metric_locked(dst, RTAX_CWND))
114 val |= 1 << TCP_METRIC_CWND;
115 if (dst_metric_locked(dst, RTAX_REORDERING))
116 val |= 1 << TCP_METRIC_REORDERING;
117 tm->tcpm_lock = val;
118
119 tm->tcpm_vals[TCP_METRIC_RTT] = dst_metric_raw(dst, RTAX_RTT);
120 tm->tcpm_vals[TCP_METRIC_RTTVAR] = dst_metric_raw(dst, RTAX_RTTVAR);
121 tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH);
122 tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND);
123 tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING);
124 tm->tcpm_ts = 0;
125 tm->tcpm_ts_stamp = 0;
126 if (fastopen_clear) {
127 tm->tcpm_fastopen.mss = 0;
128 tm->tcpm_fastopen.syn_loss = 0;
129 tm->tcpm_fastopen.cookie.len = 0;
130 }
131 }
132
133 static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
134 struct inetpeer_addr *addr,
135 unsigned int hash,
136 bool reclaim)
137 {
138 struct tcp_metrics_block *tm;
139 struct net *net;
140
141 spin_lock_bh(&tcp_metrics_lock);
142 net = dev_net(dst->dev);
143 if (unlikely(reclaim)) {
144 struct tcp_metrics_block *oldest;
145
146 oldest = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain);
147 for (tm = rcu_dereference(oldest->tcpm_next); tm;
148 tm = rcu_dereference(tm->tcpm_next)) {
149 if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp))
150 oldest = tm;
151 }
152 tm = oldest;
153 } else {
154 tm = kmalloc(sizeof(*tm), GFP_ATOMIC);
155 if (!tm)
156 goto out_unlock;
157 }
158 tm->tcpm_addr = *addr;
159
160 tcpm_suck_dst(tm, dst, true);
161
162 if (likely(!reclaim)) {
163 tm->tcpm_next = net->ipv4.tcp_metrics_hash[hash].chain;
164 rcu_assign_pointer(net->ipv4.tcp_metrics_hash[hash].chain, tm);
165 }
166
167 out_unlock:
168 spin_unlock_bh(&tcp_metrics_lock);
169 return tm;
170 }
171
172 #define TCP_METRICS_TIMEOUT (60 * 60 * HZ)
173
174 static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst)
175 {
176 if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT)))
177 tcpm_suck_dst(tm, dst, false);
178 }
179
180 #define TCP_METRICS_RECLAIM_DEPTH 5
181 #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL
182
183 static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth)
184 {
185 if (tm)
186 return tm;
187 if (depth > TCP_METRICS_RECLAIM_DEPTH)
188 return TCP_METRICS_RECLAIM_PTR;
189 return NULL;
190 }
191
192 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *addr,
193 struct net *net, unsigned int hash)
194 {
195 struct tcp_metrics_block *tm;
196 int depth = 0;
197
198 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
199 tm = rcu_dereference(tm->tcpm_next)) {
200 if (addr_same(&tm->tcpm_addr, addr))
201 break;
202 depth++;
203 }
204 return tcp_get_encode(tm, depth);
205 }
206
207 static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
208 struct dst_entry *dst)
209 {
210 struct tcp_metrics_block *tm;
211 struct inetpeer_addr addr;
212 unsigned int hash;
213 struct net *net;
214
215 addr.family = req->rsk_ops->family;
216 switch (addr.family) {
217 case AF_INET:
218 addr.addr.a4 = inet_rsk(req)->rmt_addr;
219 hash = (__force unsigned int) addr.addr.a4;
220 break;
221 case AF_INET6:
222 *(struct in6_addr *)addr.addr.a6 = inet6_rsk(req)->rmt_addr;
223 hash = ipv6_addr_hash(&inet6_rsk(req)->rmt_addr);
224 break;
225 default:
226 return NULL;
227 }
228
229 net = dev_net(dst->dev);
230 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
231
232 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
233 tm = rcu_dereference(tm->tcpm_next)) {
234 if (addr_same(&tm->tcpm_addr, &addr))
235 break;
236 }
237 tcpm_check_stamp(tm, dst);
238 return tm;
239 }
240
241 static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock *tw)
242 {
243 struct inet6_timewait_sock *tw6;
244 struct tcp_metrics_block *tm;
245 struct inetpeer_addr addr;
246 unsigned int hash;
247 struct net *net;
248
249 addr.family = tw->tw_family;
250 switch (addr.family) {
251 case AF_INET:
252 addr.addr.a4 = tw->tw_daddr;
253 hash = (__force unsigned int) addr.addr.a4;
254 break;
255 case AF_INET6:
256 tw6 = inet6_twsk((struct sock *)tw);
257 *(struct in6_addr *)addr.addr.a6 = tw6->tw_v6_daddr;
258 hash = ipv6_addr_hash(&tw6->tw_v6_daddr);
259 break;
260 default:
261 return NULL;
262 }
263
264 net = twsk_net(tw);
265 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
266
267 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
268 tm = rcu_dereference(tm->tcpm_next)) {
269 if (addr_same(&tm->tcpm_addr, &addr))
270 break;
271 }
272 return tm;
273 }
274
275 static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk,
276 struct dst_entry *dst,
277 bool create)
278 {
279 struct tcp_metrics_block *tm;
280 struct inetpeer_addr addr;
281 unsigned int hash;
282 struct net *net;
283 bool reclaim;
284
285 addr.family = sk->sk_family;
286 switch (addr.family) {
287 case AF_INET:
288 addr.addr.a4 = inet_sk(sk)->inet_daddr;
289 hash = (__force unsigned int) addr.addr.a4;
290 break;
291 case AF_INET6:
292 *(struct in6_addr *)addr.addr.a6 = inet6_sk(sk)->daddr;
293 hash = ipv6_addr_hash(&inet6_sk(sk)->daddr);
294 break;
295 default:
296 return NULL;
297 }
298
299 net = dev_net(dst->dev);
300 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
301
302 tm = __tcp_get_metrics(&addr, net, hash);
303 reclaim = false;
304 if (tm == TCP_METRICS_RECLAIM_PTR) {
305 reclaim = true;
306 tm = NULL;
307 }
308 if (!tm && create)
309 tm = tcpm_new(dst, &addr, hash, reclaim);
310 else
311 tcpm_check_stamp(tm, dst);
312
313 return tm;
314 }
315
316 /* Save metrics learned by this TCP session. This function is called
317 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT
318 * or goes from LAST-ACK to CLOSE.
319 */
320 void tcp_update_metrics(struct sock *sk)
321 {
322 const struct inet_connection_sock *icsk = inet_csk(sk);
323 struct dst_entry *dst = __sk_dst_get(sk);
324 struct tcp_sock *tp = tcp_sk(sk);
325 struct tcp_metrics_block *tm;
326 unsigned long rtt;
327 u32 val;
328 int m;
329
330 if (sysctl_tcp_nometrics_save || !dst)
331 return;
332
333 if (dst->flags & DST_HOST)
334 dst_confirm(dst);
335
336 rcu_read_lock();
337 if (icsk->icsk_backoff || !tp->srtt) {
338 /* This session failed to estimate rtt. Why?
339 * Probably, no packets returned in time. Reset our
340 * results.
341 */
342 tm = tcp_get_metrics(sk, dst, false);
343 if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT))
344 tcp_metric_set(tm, TCP_METRIC_RTT, 0);
345 goto out_unlock;
346 } else
347 tm = tcp_get_metrics(sk, dst, true);
348
349 if (!tm)
350 goto out_unlock;
351
352 rtt = tcp_metric_get_jiffies(tm, TCP_METRIC_RTT);
353 m = rtt - tp->srtt;
354
355 /* If newly calculated rtt larger than stored one, store new
356 * one. Otherwise, use EWMA. Remember, rtt overestimation is
357 * always better than underestimation.
358 */
359 if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) {
360 if (m <= 0)
361 rtt = tp->srtt;
362 else
363 rtt -= (m >> 3);
364 tcp_metric_set_msecs(tm, TCP_METRIC_RTT, rtt);
365 }
366
367 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) {
368 unsigned long var;
369
370 if (m < 0)
371 m = -m;
372
373 /* Scale deviation to rttvar fixed point */
374 m >>= 1;
375 if (m < tp->mdev)
376 m = tp->mdev;
377
378 var = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR);
379 if (m >= var)
380 var = m;
381 else
382 var -= (var - m) >> 2;
383
384 tcp_metric_set_msecs(tm, TCP_METRIC_RTTVAR, var);
385 }
386
387 if (tcp_in_initial_slowstart(tp)) {
388 /* Slow start still did not finish. */
389 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
390 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
391 if (val && (tp->snd_cwnd >> 1) > val)
392 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
393 tp->snd_cwnd >> 1);
394 }
395 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
396 val = tcp_metric_get(tm, TCP_METRIC_CWND);
397 if (tp->snd_cwnd > val)
398 tcp_metric_set(tm, TCP_METRIC_CWND,
399 tp->snd_cwnd);
400 }
401 } else if (tp->snd_cwnd > tp->snd_ssthresh &&
402 icsk->icsk_ca_state == TCP_CA_Open) {
403 /* Cong. avoidance phase, cwnd is reliable. */
404 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH))
405 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
406 max(tp->snd_cwnd >> 1, tp->snd_ssthresh));
407 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
408 val = tcp_metric_get(tm, TCP_METRIC_CWND);
409 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1);
410 }
411 } else {
412 /* Else slow start did not finish, cwnd is non-sense,
413 * ssthresh may be also invalid.
414 */
415 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
416 val = tcp_metric_get(tm, TCP_METRIC_CWND);
417 tcp_metric_set(tm, TCP_METRIC_CWND,
418 (val + tp->snd_ssthresh) >> 1);
419 }
420 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
421 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
422 if (val && tp->snd_ssthresh > val)
423 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
424 tp->snd_ssthresh);
425 }
426 if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) {
427 val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
428 if (val < tp->reordering &&
429 tp->reordering != sysctl_tcp_reordering)
430 tcp_metric_set(tm, TCP_METRIC_REORDERING,
431 tp->reordering);
432 }
433 }
434 tm->tcpm_stamp = jiffies;
435 out_unlock:
436 rcu_read_unlock();
437 }
438
439 /* Initialize metrics on socket. */
440
441 void tcp_init_metrics(struct sock *sk)
442 {
443 struct dst_entry *dst = __sk_dst_get(sk);
444 struct tcp_sock *tp = tcp_sk(sk);
445 struct tcp_metrics_block *tm;
446 u32 val, crtt = 0; /* cached RTT scaled by 8 */
447
448 if (dst == NULL)
449 goto reset;
450
451 dst_confirm(dst);
452
453 rcu_read_lock();
454 tm = tcp_get_metrics(sk, dst, true);
455 if (!tm) {
456 rcu_read_unlock();
457 goto reset;
458 }
459
460 if (tcp_metric_locked(tm, TCP_METRIC_CWND))
461 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND);
462
463 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
464 if (val) {
465 tp->snd_ssthresh = val;
466 if (tp->snd_ssthresh > tp->snd_cwnd_clamp)
467 tp->snd_ssthresh = tp->snd_cwnd_clamp;
468 } else {
469 /* ssthresh may have been reduced unnecessarily during.
470 * 3WHS. Restore it back to its initial default.
471 */
472 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
473 }
474 val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
475 if (val && tp->reordering != val) {
476 tcp_disable_fack(tp);
477 tcp_disable_early_retrans(tp);
478 tp->reordering = val;
479 }
480
481 crtt = tcp_metric_get_jiffies(tm, TCP_METRIC_RTT);
482 rcu_read_unlock();
483 reset:
484 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal
485 * to seed the RTO for later data packets because SYN packets are
486 * small. Use the per-dst cached values to seed the RTO but keep
487 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar).
488 * Later the RTO will be updated immediately upon obtaining the first
489 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only
490 * influences the first RTO but not later RTT estimation.
491 *
492 * But if RTT is not available from the SYN (due to retransmits or
493 * syn cookies) or the cache, force a conservative 3secs timeout.
494 *
495 * A bit of theory. RTT is time passed after "normal" sized packet
496 * is sent until it is ACKed. In normal circumstances sending small
497 * packets force peer to delay ACKs and calculation is correct too.
498 * The algorithm is adaptive and, provided we follow specs, it
499 * NEVER underestimate RTT. BUT! If peer tries to make some clever
500 * tricks sort of "quick acks" for time long enough to decrease RTT
501 * to low value, and then abruptly stops to do it and starts to delay
502 * ACKs, wait for troubles.
503 */
504 if (crtt > tp->srtt) {
505 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */
506 crtt >>= 3;
507 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk));
508 } else if (tp->srtt == 0) {
509 /* RFC6298: 5.7 We've failed to get a valid RTT sample from
510 * 3WHS. This is most likely due to retransmission,
511 * including spurious one. Reset the RTO back to 3secs
512 * from the more aggressive 1sec to avoid more spurious
513 * retransmission.
514 */
515 tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK;
516 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK;
517 }
518 /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been
519 * retransmitted. In light of RFC6298 more aggressive 1sec
520 * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK
521 * retransmission has occurred.
522 */
523 if (tp->total_retrans > 1)
524 tp->snd_cwnd = 1;
525 else
526 tp->snd_cwnd = tcp_init_cwnd(tp, dst);
527 tp->snd_cwnd_stamp = tcp_time_stamp;
528 }
529
530 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check)
531 {
532 struct tcp_metrics_block *tm;
533 bool ret;
534
535 if (!dst)
536 return false;
537
538 rcu_read_lock();
539 tm = __tcp_get_metrics_req(req, dst);
540 if (paws_check) {
541 if (tm &&
542 (u32)get_seconds() - tm->tcpm_ts_stamp < TCP_PAWS_MSL &&
543 (s32)(tm->tcpm_ts - req->ts_recent) > TCP_PAWS_WINDOW)
544 ret = false;
545 else
546 ret = true;
547 } else {
548 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT) && tm->tcpm_ts_stamp)
549 ret = true;
550 else
551 ret = false;
552 }
553 rcu_read_unlock();
554
555 return ret;
556 }
557 EXPORT_SYMBOL_GPL(tcp_peer_is_proven);
558
559 void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst)
560 {
561 struct tcp_metrics_block *tm;
562
563 rcu_read_lock();
564 tm = tcp_get_metrics(sk, dst, true);
565 if (tm) {
566 struct tcp_sock *tp = tcp_sk(sk);
567
568 if ((u32)get_seconds() - tm->tcpm_ts_stamp <= TCP_PAWS_MSL) {
569 tp->rx_opt.ts_recent_stamp = tm->tcpm_ts_stamp;
570 tp->rx_opt.ts_recent = tm->tcpm_ts;
571 }
572 }
573 rcu_read_unlock();
574 }
575 EXPORT_SYMBOL_GPL(tcp_fetch_timewait_stamp);
576
577 /* VJ's idea. Save last timestamp seen from this destination and hold
578 * it at least for normal timewait interval to use for duplicate
579 * segment detection in subsequent connections, before they enter
580 * synchronized state.
581 */
582 bool tcp_remember_stamp(struct sock *sk)
583 {
584 struct dst_entry *dst = __sk_dst_get(sk);
585 bool ret = false;
586
587 if (dst) {
588 struct tcp_metrics_block *tm;
589
590 rcu_read_lock();
591 tm = tcp_get_metrics(sk, dst, true);
592 if (tm) {
593 struct tcp_sock *tp = tcp_sk(sk);
594
595 if ((s32)(tm->tcpm_ts - tp->rx_opt.ts_recent) <= 0 ||
596 ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL &&
597 tm->tcpm_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) {
598 tm->tcpm_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp;
599 tm->tcpm_ts = tp->rx_opt.ts_recent;
600 }
601 ret = true;
602 }
603 rcu_read_unlock();
604 }
605 return ret;
606 }
607
608 bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw)
609 {
610 struct tcp_metrics_block *tm;
611 bool ret = false;
612
613 rcu_read_lock();
614 tm = __tcp_get_metrics_tw(tw);
615 if (tm) {
616 const struct tcp_timewait_sock *tcptw;
617 struct sock *sk = (struct sock *) tw;
618
619 tcptw = tcp_twsk(sk);
620 if ((s32)(tm->tcpm_ts - tcptw->tw_ts_recent) <= 0 ||
621 ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL &&
622 tm->tcpm_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) {
623 tm->tcpm_ts_stamp = (u32)tcptw->tw_ts_recent_stamp;
624 tm->tcpm_ts = tcptw->tw_ts_recent;
625 }
626 ret = true;
627 }
628 rcu_read_unlock();
629
630 return ret;
631 }
632
633 static DEFINE_SEQLOCK(fastopen_seqlock);
634
635 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
636 struct tcp_fastopen_cookie *cookie,
637 int *syn_loss, unsigned long *last_syn_loss)
638 {
639 struct tcp_metrics_block *tm;
640
641 rcu_read_lock();
642 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false);
643 if (tm) {
644 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
645 unsigned int seq;
646
647 do {
648 seq = read_seqbegin(&fastopen_seqlock);
649 if (tfom->mss)
650 *mss = tfom->mss;
651 *cookie = tfom->cookie;
652 *syn_loss = tfom->syn_loss;
653 *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0;
654 } while (read_seqretry(&fastopen_seqlock, seq));
655 }
656 rcu_read_unlock();
657 }
658
659 void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
660 struct tcp_fastopen_cookie *cookie, bool syn_lost)
661 {
662 struct tcp_metrics_block *tm;
663
664 rcu_read_lock();
665 tm = tcp_get_metrics(sk, __sk_dst_get(sk), true);
666 if (tm) {
667 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
668
669 write_seqlock_bh(&fastopen_seqlock);
670 tfom->mss = mss;
671 if (cookie->len > 0)
672 tfom->cookie = *cookie;
673 if (syn_lost) {
674 ++tfom->syn_loss;
675 tfom->last_syn_loss = jiffies;
676 } else
677 tfom->syn_loss = 0;
678 write_sequnlock_bh(&fastopen_seqlock);
679 }
680 rcu_read_unlock();
681 }
682
683 static struct genl_family tcp_metrics_nl_family = {
684 .id = GENL_ID_GENERATE,
685 .hdrsize = 0,
686 .name = TCP_METRICS_GENL_NAME,
687 .version = TCP_METRICS_GENL_VERSION,
688 .maxattr = TCP_METRICS_ATTR_MAX,
689 .netnsok = true,
690 };
691
692 static struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = {
693 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, },
694 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY,
695 .len = sizeof(struct in6_addr), },
696 /* Following attributes are not received for GET/DEL,
697 * we keep them for reference
698 */
699 #if 0
700 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, },
701 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, },
702 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, },
703 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, },
704 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, },
705 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, },
706 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, },
707 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY,
708 .len = TCP_FASTOPEN_COOKIE_MAX, },
709 #endif
710 };
711
712 /* Add attributes, caller cancels its header on failure */
713 static int tcp_metrics_fill_info(struct sk_buff *msg,
714 struct tcp_metrics_block *tm)
715 {
716 struct nlattr *nest;
717 int i;
718
719 switch (tm->tcpm_addr.family) {
720 case AF_INET:
721 if (nla_put_be32(msg, TCP_METRICS_ATTR_ADDR_IPV4,
722 tm->tcpm_addr.addr.a4) < 0)
723 goto nla_put_failure;
724 break;
725 case AF_INET6:
726 if (nla_put(msg, TCP_METRICS_ATTR_ADDR_IPV6, 16,
727 tm->tcpm_addr.addr.a6) < 0)
728 goto nla_put_failure;
729 break;
730 default:
731 return -EAFNOSUPPORT;
732 }
733
734 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE,
735 jiffies - tm->tcpm_stamp) < 0)
736 goto nla_put_failure;
737 if (tm->tcpm_ts_stamp) {
738 if (nla_put_s32(msg, TCP_METRICS_ATTR_TW_TS_STAMP,
739 (s32) (get_seconds() - tm->tcpm_ts_stamp)) < 0)
740 goto nla_put_failure;
741 if (nla_put_u32(msg, TCP_METRICS_ATTR_TW_TSVAL,
742 tm->tcpm_ts) < 0)
743 goto nla_put_failure;
744 }
745
746 {
747 int n = 0;
748
749 nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS);
750 if (!nest)
751 goto nla_put_failure;
752 for (i = 0; i < TCP_METRIC_MAX + 1; i++) {
753 if (!tm->tcpm_vals[i])
754 continue;
755 if (nla_put_u32(msg, i + 1, tm->tcpm_vals[i]) < 0)
756 goto nla_put_failure;
757 n++;
758 }
759 if (n)
760 nla_nest_end(msg, nest);
761 else
762 nla_nest_cancel(msg, nest);
763 }
764
765 {
766 struct tcp_fastopen_metrics tfom_copy[1], *tfom;
767 unsigned int seq;
768
769 do {
770 seq = read_seqbegin(&fastopen_seqlock);
771 tfom_copy[0] = tm->tcpm_fastopen;
772 } while (read_seqretry(&fastopen_seqlock, seq));
773
774 tfom = tfom_copy;
775 if (tfom->mss &&
776 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS,
777 tfom->mss) < 0)
778 goto nla_put_failure;
779 if (tfom->syn_loss &&
780 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS,
781 tfom->syn_loss) < 0 ||
782 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS,
783 jiffies - tfom->last_syn_loss) < 0))
784 goto nla_put_failure;
785 if (tfom->cookie.len > 0 &&
786 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE,
787 tfom->cookie.len, tfom->cookie.val) < 0)
788 goto nla_put_failure;
789 }
790
791 return 0;
792
793 nla_put_failure:
794 return -EMSGSIZE;
795 }
796
797 static int tcp_metrics_dump_info(struct sk_buff *skb,
798 struct netlink_callback *cb,
799 struct tcp_metrics_block *tm)
800 {
801 void *hdr;
802
803 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
804 &tcp_metrics_nl_family, NLM_F_MULTI,
805 TCP_METRICS_CMD_GET);
806 if (!hdr)
807 return -EMSGSIZE;
808
809 if (tcp_metrics_fill_info(skb, tm) < 0)
810 goto nla_put_failure;
811
812 return genlmsg_end(skb, hdr);
813
814 nla_put_failure:
815 genlmsg_cancel(skb, hdr);
816 return -EMSGSIZE;
817 }
818
819 static int tcp_metrics_nl_dump(struct sk_buff *skb,
820 struct netlink_callback *cb)
821 {
822 struct net *net = sock_net(skb->sk);
823 unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log;
824 unsigned int row, s_row = cb->args[0];
825 int s_col = cb->args[1], col = s_col;
826
827 for (row = s_row; row < max_rows; row++, s_col = 0) {
828 struct tcp_metrics_block *tm;
829 struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash + row;
830
831 rcu_read_lock();
832 for (col = 0, tm = rcu_dereference(hb->chain); tm;
833 tm = rcu_dereference(tm->tcpm_next), col++) {
834 if (col < s_col)
835 continue;
836 if (tcp_metrics_dump_info(skb, cb, tm) < 0) {
837 rcu_read_unlock();
838 goto done;
839 }
840 }
841 rcu_read_unlock();
842 }
843
844 done:
845 cb->args[0] = row;
846 cb->args[1] = col;
847 return skb->len;
848 }
849
850 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
851 unsigned int *hash, int optional)
852 {
853 struct nlattr *a;
854
855 a = info->attrs[TCP_METRICS_ATTR_ADDR_IPV4];
856 if (a) {
857 addr->family = AF_INET;
858 addr->addr.a4 = nla_get_be32(a);
859 *hash = (__force unsigned int) addr->addr.a4;
860 return 0;
861 }
862 a = info->attrs[TCP_METRICS_ATTR_ADDR_IPV6];
863 if (a) {
864 if (nla_len(a) != sizeof(struct in6_addr))
865 return -EINVAL;
866 addr->family = AF_INET6;
867 memcpy(addr->addr.a6, nla_data(a), sizeof(addr->addr.a6));
868 *hash = ipv6_addr_hash((struct in6_addr *) addr->addr.a6);
869 return 0;
870 }
871 return optional ? 1 : -EAFNOSUPPORT;
872 }
873
874 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
875 {
876 struct tcp_metrics_block *tm;
877 struct inetpeer_addr addr;
878 unsigned int hash;
879 struct sk_buff *msg;
880 struct net *net = genl_info_net(info);
881 void *reply;
882 int ret;
883
884 ret = parse_nl_addr(info, &addr, &hash, 0);
885 if (ret < 0)
886 return ret;
887
888 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
889 if (!msg)
890 return -ENOMEM;
891
892 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0,
893 info->genlhdr->cmd);
894 if (!reply)
895 goto nla_put_failure;
896
897 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
898 ret = -ESRCH;
899 rcu_read_lock();
900 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
901 tm = rcu_dereference(tm->tcpm_next)) {
902 if (addr_same(&tm->tcpm_addr, &addr)) {
903 ret = tcp_metrics_fill_info(msg, tm);
904 break;
905 }
906 }
907 rcu_read_unlock();
908 if (ret < 0)
909 goto out_free;
910
911 genlmsg_end(msg, reply);
912 return genlmsg_reply(msg, info);
913
914 nla_put_failure:
915 ret = -EMSGSIZE;
916
917 out_free:
918 nlmsg_free(msg);
919 return ret;
920 }
921
922 #define deref_locked_genl(p) \
923 rcu_dereference_protected(p, lockdep_genl_is_held() && \
924 lockdep_is_held(&tcp_metrics_lock))
925
926 #define deref_genl(p) rcu_dereference_protected(p, lockdep_genl_is_held())
927
928 static int tcp_metrics_flush_all(struct net *net)
929 {
930 unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log;
931 struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash;
932 struct tcp_metrics_block *tm;
933 unsigned int row;
934
935 for (row = 0; row < max_rows; row++, hb++) {
936 spin_lock_bh(&tcp_metrics_lock);
937 tm = deref_locked_genl(hb->chain);
938 if (tm)
939 hb->chain = NULL;
940 spin_unlock_bh(&tcp_metrics_lock);
941 while (tm) {
942 struct tcp_metrics_block *next;
943
944 next = deref_genl(tm->tcpm_next);
945 kfree_rcu(tm, rcu_head);
946 tm = next;
947 }
948 }
949 return 0;
950 }
951
952 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info)
953 {
954 struct tcpm_hash_bucket *hb;
955 struct tcp_metrics_block *tm;
956 struct tcp_metrics_block __rcu **pp;
957 struct inetpeer_addr addr;
958 unsigned int hash;
959 struct net *net = genl_info_net(info);
960 int ret;
961
962 ret = parse_nl_addr(info, &addr, &hash, 1);
963 if (ret < 0)
964 return ret;
965 if (ret > 0)
966 return tcp_metrics_flush_all(net);
967
968 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
969 hb = net->ipv4.tcp_metrics_hash + hash;
970 pp = &hb->chain;
971 spin_lock_bh(&tcp_metrics_lock);
972 for (tm = deref_locked_genl(*pp); tm;
973 pp = &tm->tcpm_next, tm = deref_locked_genl(*pp)) {
974 if (addr_same(&tm->tcpm_addr, &addr)) {
975 *pp = tm->tcpm_next;
976 break;
977 }
978 }
979 spin_unlock_bh(&tcp_metrics_lock);
980 if (!tm)
981 return -ESRCH;
982 kfree_rcu(tm, rcu_head);
983 return 0;
984 }
985
986 static struct genl_ops tcp_metrics_nl_ops[] = {
987 {
988 .cmd = TCP_METRICS_CMD_GET,
989 .doit = tcp_metrics_nl_cmd_get,
990 .dumpit = tcp_metrics_nl_dump,
991 .policy = tcp_metrics_nl_policy,
992 .flags = GENL_ADMIN_PERM,
993 },
994 {
995 .cmd = TCP_METRICS_CMD_DEL,
996 .doit = tcp_metrics_nl_cmd_del,
997 .policy = tcp_metrics_nl_policy,
998 .flags = GENL_ADMIN_PERM,
999 },
1000 };
1001
1002 static unsigned int tcpmhash_entries;
1003 static int __init set_tcpmhash_entries(char *str)
1004 {
1005 ssize_t ret;
1006
1007 if (!str)
1008 return 0;
1009
1010 ret = kstrtouint(str, 0, &tcpmhash_entries);
1011 if (ret)
1012 return 0;
1013
1014 return 1;
1015 }
1016 __setup("tcpmhash_entries=", set_tcpmhash_entries);
1017
1018 static int __net_init tcp_net_metrics_init(struct net *net)
1019 {
1020 size_t size;
1021 unsigned int slots;
1022
1023 slots = tcpmhash_entries;
1024 if (!slots) {
1025 if (totalram_pages >= 128 * 1024)
1026 slots = 16 * 1024;
1027 else
1028 slots = 8 * 1024;
1029 }
1030
1031 net->ipv4.tcp_metrics_hash_log = order_base_2(slots);
1032 size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log;
1033
1034 net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
1035 if (!net->ipv4.tcp_metrics_hash)
1036 net->ipv4.tcp_metrics_hash = vzalloc(size);
1037
1038 if (!net->ipv4.tcp_metrics_hash)
1039 return -ENOMEM;
1040
1041 return 0;
1042 }
1043
1044 static void __net_exit tcp_net_metrics_exit(struct net *net)
1045 {
1046 unsigned int i;
1047
1048 for (i = 0; i < (1U << net->ipv4.tcp_metrics_hash_log) ; i++) {
1049 struct tcp_metrics_block *tm, *next;
1050
1051 tm = rcu_dereference_protected(net->ipv4.tcp_metrics_hash[i].chain, 1);
1052 while (tm) {
1053 next = rcu_dereference_protected(tm->tcpm_next, 1);
1054 kfree(tm);
1055 tm = next;
1056 }
1057 }
1058 if (is_vmalloc_addr(net->ipv4.tcp_metrics_hash))
1059 vfree(net->ipv4.tcp_metrics_hash);
1060 else
1061 kfree(net->ipv4.tcp_metrics_hash);
1062 }
1063
1064 static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
1065 .init = tcp_net_metrics_init,
1066 .exit = tcp_net_metrics_exit,
1067 };
1068
1069 void __init tcp_metrics_init(void)
1070 {
1071 int ret;
1072
1073 ret = register_pernet_subsys(&tcp_net_metrics_ops);
1074 if (ret < 0)
1075 goto cleanup;
1076 ret = genl_register_family_with_ops(&tcp_metrics_nl_family,
1077 tcp_metrics_nl_ops,
1078 ARRAY_SIZE(tcp_metrics_nl_ops));
1079 if (ret < 0)
1080 goto cleanup_subsys;
1081 return;
1082
1083 cleanup_subsys:
1084 unregister_pernet_subsys(&tcp_net_metrics_ops);
1085
1086 cleanup:
1087 return;
1088 }
Linux kernel - Deliverables
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