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Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[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 inet_csk(sk)->icsk_rto = crtt + max(crtt >> 2, tcp_rto_min(sk));
506 } else if (tp->srtt == 0) {
507 /* RFC6298: 5.7 We've failed to get a valid RTT sample from
508 * 3WHS. This is most likely due to retransmission,
509 * including spurious one. Reset the RTO back to 3secs
510 * from the more aggressive 1sec to avoid more spurious
511 * retransmission.
512 */
513 tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK;
514 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK;
515 }
516 /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been
517 * retransmitted. In light of RFC6298 more aggressive 1sec
518 * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK
519 * retransmission has occurred.
520 */
521 if (tp->total_retrans > 1)
522 tp->snd_cwnd = 1;
523 else
524 tp->snd_cwnd = tcp_init_cwnd(tp, dst);
525 tp->snd_cwnd_stamp = tcp_time_stamp;
526 }
527
528 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check)
529 {
530 struct tcp_metrics_block *tm;
531 bool ret;
532
533 if (!dst)
534 return false;
535
536 rcu_read_lock();
537 tm = __tcp_get_metrics_req(req, dst);
538 if (paws_check) {
539 if (tm &&
540 (u32)get_seconds() - tm->tcpm_ts_stamp < TCP_PAWS_MSL &&
541 (s32)(tm->tcpm_ts - req->ts_recent) > TCP_PAWS_WINDOW)
542 ret = false;
543 else
544 ret = true;
545 } else {
546 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT) && tm->tcpm_ts_stamp)
547 ret = true;
548 else
549 ret = false;
550 }
551 rcu_read_unlock();
552
553 return ret;
554 }
555 EXPORT_SYMBOL_GPL(tcp_peer_is_proven);
556
557 void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst)
558 {
559 struct tcp_metrics_block *tm;
560
561 rcu_read_lock();
562 tm = tcp_get_metrics(sk, dst, true);
563 if (tm) {
564 struct tcp_sock *tp = tcp_sk(sk);
565
566 if ((u32)get_seconds() - tm->tcpm_ts_stamp <= TCP_PAWS_MSL) {
567 tp->rx_opt.ts_recent_stamp = tm->tcpm_ts_stamp;
568 tp->rx_opt.ts_recent = tm->tcpm_ts;
569 }
570 }
571 rcu_read_unlock();
572 }
573 EXPORT_SYMBOL_GPL(tcp_fetch_timewait_stamp);
574
575 /* VJ's idea. Save last timestamp seen from this destination and hold
576 * it at least for normal timewait interval to use for duplicate
577 * segment detection in subsequent connections, before they enter
578 * synchronized state.
579 */
580 bool tcp_remember_stamp(struct sock *sk)
581 {
582 struct dst_entry *dst = __sk_dst_get(sk);
583 bool ret = false;
584
585 if (dst) {
586 struct tcp_metrics_block *tm;
587
588 rcu_read_lock();
589 tm = tcp_get_metrics(sk, dst, true);
590 if (tm) {
591 struct tcp_sock *tp = tcp_sk(sk);
592
593 if ((s32)(tm->tcpm_ts - tp->rx_opt.ts_recent) <= 0 ||
594 ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL &&
595 tm->tcpm_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) {
596 tm->tcpm_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp;
597 tm->tcpm_ts = tp->rx_opt.ts_recent;
598 }
599 ret = true;
600 }
601 rcu_read_unlock();
602 }
603 return ret;
604 }
605
606 bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw)
607 {
608 struct tcp_metrics_block *tm;
609 bool ret = false;
610
611 rcu_read_lock();
612 tm = __tcp_get_metrics_tw(tw);
613 if (tm) {
614 const struct tcp_timewait_sock *tcptw;
615 struct sock *sk = (struct sock *) tw;
616
617 tcptw = tcp_twsk(sk);
618 if ((s32)(tm->tcpm_ts - tcptw->tw_ts_recent) <= 0 ||
619 ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL &&
620 tm->tcpm_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) {
621 tm->tcpm_ts_stamp = (u32)tcptw->tw_ts_recent_stamp;
622 tm->tcpm_ts = tcptw->tw_ts_recent;
623 }
624 ret = true;
625 }
626 rcu_read_unlock();
627
628 return ret;
629 }
630
631 static DEFINE_SEQLOCK(fastopen_seqlock);
632
633 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
634 struct tcp_fastopen_cookie *cookie,
635 int *syn_loss, unsigned long *last_syn_loss)
636 {
637 struct tcp_metrics_block *tm;
638
639 rcu_read_lock();
640 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false);
641 if (tm) {
642 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
643 unsigned int seq;
644
645 do {
646 seq = read_seqbegin(&fastopen_seqlock);
647 if (tfom->mss)
648 *mss = tfom->mss;
649 *cookie = tfom->cookie;
650 *syn_loss = tfom->syn_loss;
651 *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0;
652 } while (read_seqretry(&fastopen_seqlock, seq));
653 }
654 rcu_read_unlock();
655 }
656
657 void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
658 struct tcp_fastopen_cookie *cookie, bool syn_lost)
659 {
660 struct tcp_metrics_block *tm;
661
662 rcu_read_lock();
663 tm = tcp_get_metrics(sk, __sk_dst_get(sk), true);
664 if (tm) {
665 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
666
667 write_seqlock_bh(&fastopen_seqlock);
668 tfom->mss = mss;
669 if (cookie->len > 0)
670 tfom->cookie = *cookie;
671 if (syn_lost) {
672 ++tfom->syn_loss;
673 tfom->last_syn_loss = jiffies;
674 } else
675 tfom->syn_loss = 0;
676 write_sequnlock_bh(&fastopen_seqlock);
677 }
678 rcu_read_unlock();
679 }
680
681 static struct genl_family tcp_metrics_nl_family = {
682 .id = GENL_ID_GENERATE,
683 .hdrsize = 0,
684 .name = TCP_METRICS_GENL_NAME,
685 .version = TCP_METRICS_GENL_VERSION,
686 .maxattr = TCP_METRICS_ATTR_MAX,
687 .netnsok = true,
688 };
689
690 static struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = {
691 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, },
692 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY,
693 .len = sizeof(struct in6_addr), },
694 /* Following attributes are not received for GET/DEL,
695 * we keep them for reference
696 */
697 #if 0
698 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, },
699 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, },
700 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, },
701 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, },
702 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, },
703 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, },
704 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, },
705 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY,
706 .len = TCP_FASTOPEN_COOKIE_MAX, },
707 #endif
708 };
709
710 /* Add attributes, caller cancels its header on failure */
711 static int tcp_metrics_fill_info(struct sk_buff *msg,
712 struct tcp_metrics_block *tm)
713 {
714 struct nlattr *nest;
715 int i;
716
717 switch (tm->tcpm_addr.family) {
718 case AF_INET:
719 if (nla_put_be32(msg, TCP_METRICS_ATTR_ADDR_IPV4,
720 tm->tcpm_addr.addr.a4) < 0)
721 goto nla_put_failure;
722 break;
723 case AF_INET6:
724 if (nla_put(msg, TCP_METRICS_ATTR_ADDR_IPV6, 16,
725 tm->tcpm_addr.addr.a6) < 0)
726 goto nla_put_failure;
727 break;
728 default:
729 return -EAFNOSUPPORT;
730 }
731
732 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE,
733 jiffies - tm->tcpm_stamp) < 0)
734 goto nla_put_failure;
735 if (tm->tcpm_ts_stamp) {
736 if (nla_put_s32(msg, TCP_METRICS_ATTR_TW_TS_STAMP,
737 (s32) (get_seconds() - tm->tcpm_ts_stamp)) < 0)
738 goto nla_put_failure;
739 if (nla_put_u32(msg, TCP_METRICS_ATTR_TW_TSVAL,
740 tm->tcpm_ts) < 0)
741 goto nla_put_failure;
742 }
743
744 {
745 int n = 0;
746
747 nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS);
748 if (!nest)
749 goto nla_put_failure;
750 for (i = 0; i < TCP_METRIC_MAX + 1; i++) {
751 if (!tm->tcpm_vals[i])
752 continue;
753 if (nla_put_u32(msg, i + 1, tm->tcpm_vals[i]) < 0)
754 goto nla_put_failure;
755 n++;
756 }
757 if (n)
758 nla_nest_end(msg, nest);
759 else
760 nla_nest_cancel(msg, nest);
761 }
762
763 {
764 struct tcp_fastopen_metrics tfom_copy[1], *tfom;
765 unsigned int seq;
766
767 do {
768 seq = read_seqbegin(&fastopen_seqlock);
769 tfom_copy[0] = tm->tcpm_fastopen;
770 } while (read_seqretry(&fastopen_seqlock, seq));
771
772 tfom = tfom_copy;
773 if (tfom->mss &&
774 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS,
775 tfom->mss) < 0)
776 goto nla_put_failure;
777 if (tfom->syn_loss &&
778 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS,
779 tfom->syn_loss) < 0 ||
780 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS,
781 jiffies - tfom->last_syn_loss) < 0))
782 goto nla_put_failure;
783 if (tfom->cookie.len > 0 &&
784 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE,
785 tfom->cookie.len, tfom->cookie.val) < 0)
786 goto nla_put_failure;
787 }
788
789 return 0;
790
791 nla_put_failure:
792 return -EMSGSIZE;
793 }
794
795 static int tcp_metrics_dump_info(struct sk_buff *skb,
796 struct netlink_callback *cb,
797 struct tcp_metrics_block *tm)
798 {
799 void *hdr;
800
801 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
802 &tcp_metrics_nl_family, NLM_F_MULTI,
803 TCP_METRICS_CMD_GET);
804 if (!hdr)
805 return -EMSGSIZE;
806
807 if (tcp_metrics_fill_info(skb, tm) < 0)
808 goto nla_put_failure;
809
810 return genlmsg_end(skb, hdr);
811
812 nla_put_failure:
813 genlmsg_cancel(skb, hdr);
814 return -EMSGSIZE;
815 }
816
817 static int tcp_metrics_nl_dump(struct sk_buff *skb,
818 struct netlink_callback *cb)
819 {
820 struct net *net = sock_net(skb->sk);
821 unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log;
822 unsigned int row, s_row = cb->args[0];
823 int s_col = cb->args[1], col = s_col;
824
825 for (row = s_row; row < max_rows; row++, s_col = 0) {
826 struct tcp_metrics_block *tm;
827 struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash + row;
828
829 rcu_read_lock();
830 for (col = 0, tm = rcu_dereference(hb->chain); tm;
831 tm = rcu_dereference(tm->tcpm_next), col++) {
832 if (col < s_col)
833 continue;
834 if (tcp_metrics_dump_info(skb, cb, tm) < 0) {
835 rcu_read_unlock();
836 goto done;
837 }
838 }
839 rcu_read_unlock();
840 }
841
842 done:
843 cb->args[0] = row;
844 cb->args[1] = col;
845 return skb->len;
846 }
847
848 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
849 unsigned int *hash, int optional)
850 {
851 struct nlattr *a;
852
853 a = info->attrs[TCP_METRICS_ATTR_ADDR_IPV4];
854 if (a) {
855 addr->family = AF_INET;
856 addr->addr.a4 = nla_get_be32(a);
857 *hash = (__force unsigned int) addr->addr.a4;
858 return 0;
859 }
860 a = info->attrs[TCP_METRICS_ATTR_ADDR_IPV6];
861 if (a) {
862 if (nla_len(a) != sizeof(struct in6_addr))
863 return -EINVAL;
864 addr->family = AF_INET6;
865 memcpy(addr->addr.a6, nla_data(a), sizeof(addr->addr.a6));
866 *hash = ipv6_addr_hash((struct in6_addr *) addr->addr.a6);
867 return 0;
868 }
869 return optional ? 1 : -EAFNOSUPPORT;
870 }
871
872 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
873 {
874 struct tcp_metrics_block *tm;
875 struct inetpeer_addr addr;
876 unsigned int hash;
877 struct sk_buff *msg;
878 struct net *net = genl_info_net(info);
879 void *reply;
880 int ret;
881
882 ret = parse_nl_addr(info, &addr, &hash, 0);
883 if (ret < 0)
884 return ret;
885
886 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
887 if (!msg)
888 return -ENOMEM;
889
890 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0,
891 info->genlhdr->cmd);
892 if (!reply)
893 goto nla_put_failure;
894
895 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
896 ret = -ESRCH;
897 rcu_read_lock();
898 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
899 tm = rcu_dereference(tm->tcpm_next)) {
900 if (addr_same(&tm->tcpm_addr, &addr)) {
901 ret = tcp_metrics_fill_info(msg, tm);
902 break;
903 }
904 }
905 rcu_read_unlock();
906 if (ret < 0)
907 goto out_free;
908
909 genlmsg_end(msg, reply);
910 return genlmsg_reply(msg, info);
911
912 nla_put_failure:
913 ret = -EMSGSIZE;
914
915 out_free:
916 nlmsg_free(msg);
917 return ret;
918 }
919
920 #define deref_locked_genl(p) \
921 rcu_dereference_protected(p, lockdep_genl_is_held() && \
922 lockdep_is_held(&tcp_metrics_lock))
923
924 #define deref_genl(p) rcu_dereference_protected(p, lockdep_genl_is_held())
925
926 static int tcp_metrics_flush_all(struct net *net)
927 {
928 unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log;
929 struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash;
930 struct tcp_metrics_block *tm;
931 unsigned int row;
932
933 for (row = 0; row < max_rows; row++, hb++) {
934 spin_lock_bh(&tcp_metrics_lock);
935 tm = deref_locked_genl(hb->chain);
936 if (tm)
937 hb->chain = NULL;
938 spin_unlock_bh(&tcp_metrics_lock);
939 while (tm) {
940 struct tcp_metrics_block *next;
941
942 next = deref_genl(tm->tcpm_next);
943 kfree_rcu(tm, rcu_head);
944 tm = next;
945 }
946 }
947 return 0;
948 }
949
950 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info)
951 {
952 struct tcpm_hash_bucket *hb;
953 struct tcp_metrics_block *tm;
954 struct tcp_metrics_block __rcu **pp;
955 struct inetpeer_addr addr;
956 unsigned int hash;
957 struct net *net = genl_info_net(info);
958 int ret;
959
960 ret = parse_nl_addr(info, &addr, &hash, 1);
961 if (ret < 0)
962 return ret;
963 if (ret > 0)
964 return tcp_metrics_flush_all(net);
965
966 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
967 hb = net->ipv4.tcp_metrics_hash + hash;
968 pp = &hb->chain;
969 spin_lock_bh(&tcp_metrics_lock);
970 for (tm = deref_locked_genl(*pp); tm;
971 pp = &tm->tcpm_next, tm = deref_locked_genl(*pp)) {
972 if (addr_same(&tm->tcpm_addr, &addr)) {
973 *pp = tm->tcpm_next;
974 break;
975 }
976 }
977 spin_unlock_bh(&tcp_metrics_lock);
978 if (!tm)
979 return -ESRCH;
980 kfree_rcu(tm, rcu_head);
981 return 0;
982 }
983
984 static struct genl_ops tcp_metrics_nl_ops[] = {
985 {
986 .cmd = TCP_METRICS_CMD_GET,
987 .doit = tcp_metrics_nl_cmd_get,
988 .dumpit = tcp_metrics_nl_dump,
989 .policy = tcp_metrics_nl_policy,
990 .flags = GENL_ADMIN_PERM,
991 },
992 {
993 .cmd = TCP_METRICS_CMD_DEL,
994 .doit = tcp_metrics_nl_cmd_del,
995 .policy = tcp_metrics_nl_policy,
996 .flags = GENL_ADMIN_PERM,
997 },
998 };
999
1000 static unsigned int tcpmhash_entries;
1001 static int __init set_tcpmhash_entries(char *str)
1002 {
1003 ssize_t ret;
1004
1005 if (!str)
1006 return 0;
1007
1008 ret = kstrtouint(str, 0, &tcpmhash_entries);
1009 if (ret)
1010 return 0;
1011
1012 return 1;
1013 }
1014 __setup("tcpmhash_entries=", set_tcpmhash_entries);
1015
1016 static int __net_init tcp_net_metrics_init(struct net *net)
1017 {
1018 size_t size;
1019 unsigned int slots;
1020
1021 slots = tcpmhash_entries;
1022 if (!slots) {
1023 if (totalram_pages >= 128 * 1024)
1024 slots = 16 * 1024;
1025 else
1026 slots = 8 * 1024;
1027 }
1028
1029 net->ipv4.tcp_metrics_hash_log = order_base_2(slots);
1030 size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log;
1031
1032 net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
1033 if (!net->ipv4.tcp_metrics_hash)
1034 net->ipv4.tcp_metrics_hash = vzalloc(size);
1035
1036 if (!net->ipv4.tcp_metrics_hash)
1037 return -ENOMEM;
1038
1039 return 0;
1040 }
1041
1042 static void __net_exit tcp_net_metrics_exit(struct net *net)
1043 {
1044 unsigned int i;
1045
1046 for (i = 0; i < (1U << net->ipv4.tcp_metrics_hash_log) ; i++) {
1047 struct tcp_metrics_block *tm, *next;
1048
1049 tm = rcu_dereference_protected(net->ipv4.tcp_metrics_hash[i].chain, 1);
1050 while (tm) {
1051 next = rcu_dereference_protected(tm->tcpm_next, 1);
1052 kfree(tm);
1053 tm = next;
1054 }
1055 }
1056 if (is_vmalloc_addr(net->ipv4.tcp_metrics_hash))
1057 vfree(net->ipv4.tcp_metrics_hash);
1058 else
1059 kfree(net->ipv4.tcp_metrics_hash);
1060 }
1061
1062 static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
1063 .init = tcp_net_metrics_init,
1064 .exit = tcp_net_metrics_exit,
1065 };
1066
1067 void __init tcp_metrics_init(void)
1068 {
1069 int ret;
1070
1071 ret = register_pernet_subsys(&tcp_net_metrics_ops);
1072 if (ret < 0)
1073 goto cleanup;
1074 ret = genl_register_family_with_ops(&tcp_metrics_nl_family,
1075 tcp_metrics_nl_ops,
1076 ARRAY_SIZE(tcp_metrics_nl_ops));
1077 if (ret < 0)
1078 goto cleanup_subsys;
1079 return;
1080
1081 cleanup_subsys:
1082 unregister_pernet_subsys(&tcp_net_metrics_ops);
1083
1084 cleanup:
1085 return;
1086 }
Linux kernel - Deliverables
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