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Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
[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 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr,
26 const struct inetpeer_addr *daddr,
27 struct net *net, unsigned int hash);
28
29 struct tcp_fastopen_metrics {
30 u16 mss;
31 u16 syn_loss:10; /* Recurring Fast Open SYN losses */
32 unsigned long last_syn_loss; /* Last Fast Open SYN loss */
33 struct tcp_fastopen_cookie cookie;
34 };
35
36 struct tcp_metrics_block {
37 struct tcp_metrics_block __rcu *tcpm_next;
38 struct inetpeer_addr tcpm_saddr;
39 struct inetpeer_addr tcpm_daddr;
40 unsigned long tcpm_stamp;
41 u32 tcpm_ts;
42 u32 tcpm_ts_stamp;
43 u32 tcpm_lock;
44 u32 tcpm_vals[TCP_METRIC_MAX + 1];
45 struct tcp_fastopen_metrics tcpm_fastopen;
46
47 struct rcu_head rcu_head;
48 };
49
50 static bool tcp_metric_locked(struct tcp_metrics_block *tm,
51 enum tcp_metric_index idx)
52 {
53 return tm->tcpm_lock & (1 << idx);
54 }
55
56 static u32 tcp_metric_get(struct tcp_metrics_block *tm,
57 enum tcp_metric_index idx)
58 {
59 return tm->tcpm_vals[idx];
60 }
61
62 static u32 tcp_metric_get_jiffies(struct tcp_metrics_block *tm,
63 enum tcp_metric_index idx)
64 {
65 return msecs_to_jiffies(tm->tcpm_vals[idx]);
66 }
67
68 static void tcp_metric_set(struct tcp_metrics_block *tm,
69 enum tcp_metric_index idx,
70 u32 val)
71 {
72 tm->tcpm_vals[idx] = val;
73 }
74
75 static void tcp_metric_set_msecs(struct tcp_metrics_block *tm,
76 enum tcp_metric_index idx,
77 u32 val)
78 {
79 tm->tcpm_vals[idx] = jiffies_to_msecs(val);
80 }
81
82 static bool addr_same(const struct inetpeer_addr *a,
83 const struct inetpeer_addr *b)
84 {
85 const struct in6_addr *a6, *b6;
86
87 if (a->family != b->family)
88 return false;
89 if (a->family == AF_INET)
90 return a->addr.a4 == b->addr.a4;
91
92 a6 = (const struct in6_addr *) &a->addr.a6[0];
93 b6 = (const struct in6_addr *) &b->addr.a6[0];
94
95 return ipv6_addr_equal(a6, b6);
96 }
97
98 struct tcpm_hash_bucket {
99 struct tcp_metrics_block __rcu *chain;
100 };
101
102 static DEFINE_SPINLOCK(tcp_metrics_lock);
103
104 static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst,
105 bool fastopen_clear)
106 {
107 u32 val;
108
109 tm->tcpm_stamp = jiffies;
110
111 val = 0;
112 if (dst_metric_locked(dst, RTAX_RTT))
113 val |= 1 << TCP_METRIC_RTT;
114 if (dst_metric_locked(dst, RTAX_RTTVAR))
115 val |= 1 << TCP_METRIC_RTTVAR;
116 if (dst_metric_locked(dst, RTAX_SSTHRESH))
117 val |= 1 << TCP_METRIC_SSTHRESH;
118 if (dst_metric_locked(dst, RTAX_CWND))
119 val |= 1 << TCP_METRIC_CWND;
120 if (dst_metric_locked(dst, RTAX_REORDERING))
121 val |= 1 << TCP_METRIC_REORDERING;
122 tm->tcpm_lock = val;
123
124 tm->tcpm_vals[TCP_METRIC_RTT] = dst_metric_raw(dst, RTAX_RTT);
125 tm->tcpm_vals[TCP_METRIC_RTTVAR] = dst_metric_raw(dst, RTAX_RTTVAR);
126 tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH);
127 tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND);
128 tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING);
129 tm->tcpm_ts = 0;
130 tm->tcpm_ts_stamp = 0;
131 if (fastopen_clear) {
132 tm->tcpm_fastopen.mss = 0;
133 tm->tcpm_fastopen.syn_loss = 0;
134 tm->tcpm_fastopen.cookie.len = 0;
135 }
136 }
137
138 #define TCP_METRICS_TIMEOUT (60 * 60 * HZ)
139
140 static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst)
141 {
142 if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT)))
143 tcpm_suck_dst(tm, dst, false);
144 }
145
146 #define TCP_METRICS_RECLAIM_DEPTH 5
147 #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL
148
149 static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
150 struct inetpeer_addr *saddr,
151 struct inetpeer_addr *daddr,
152 unsigned int hash)
153 {
154 struct tcp_metrics_block *tm;
155 struct net *net;
156 bool reclaim = false;
157
158 spin_lock_bh(&tcp_metrics_lock);
159 net = dev_net(dst->dev);
160
161 /* While waiting for the spin-lock the cache might have been populated
162 * with this entry and so we have to check again.
163 */
164 tm = __tcp_get_metrics(saddr, daddr, net, hash);
165 if (tm == TCP_METRICS_RECLAIM_PTR) {
166 reclaim = true;
167 tm = NULL;
168 }
169 if (tm) {
170 tcpm_check_stamp(tm, dst);
171 goto out_unlock;
172 }
173
174 if (unlikely(reclaim)) {
175 struct tcp_metrics_block *oldest;
176
177 oldest = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain);
178 for (tm = rcu_dereference(oldest->tcpm_next); tm;
179 tm = rcu_dereference(tm->tcpm_next)) {
180 if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp))
181 oldest = tm;
182 }
183 tm = oldest;
184 } else {
185 tm = kmalloc(sizeof(*tm), GFP_ATOMIC);
186 if (!tm)
187 goto out_unlock;
188 }
189 tm->tcpm_saddr = *saddr;
190 tm->tcpm_daddr = *daddr;
191
192 tcpm_suck_dst(tm, dst, true);
193
194 if (likely(!reclaim)) {
195 tm->tcpm_next = net->ipv4.tcp_metrics_hash[hash].chain;
196 rcu_assign_pointer(net->ipv4.tcp_metrics_hash[hash].chain, tm);
197 }
198
199 out_unlock:
200 spin_unlock_bh(&tcp_metrics_lock);
201 return tm;
202 }
203
204 static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth)
205 {
206 if (tm)
207 return tm;
208 if (depth > TCP_METRICS_RECLAIM_DEPTH)
209 return TCP_METRICS_RECLAIM_PTR;
210 return NULL;
211 }
212
213 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr,
214 const struct inetpeer_addr *daddr,
215 struct net *net, unsigned int hash)
216 {
217 struct tcp_metrics_block *tm;
218 int depth = 0;
219
220 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
221 tm = rcu_dereference(tm->tcpm_next)) {
222 if (addr_same(&tm->tcpm_saddr, saddr) &&
223 addr_same(&tm->tcpm_daddr, daddr))
224 break;
225 depth++;
226 }
227 return tcp_get_encode(tm, depth);
228 }
229
230 static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
231 struct dst_entry *dst)
232 {
233 struct tcp_metrics_block *tm;
234 struct inetpeer_addr saddr, daddr;
235 unsigned int hash;
236 struct net *net;
237
238 saddr.family = req->rsk_ops->family;
239 daddr.family = req->rsk_ops->family;
240 switch (daddr.family) {
241 case AF_INET:
242 saddr.addr.a4 = inet_rsk(req)->ir_loc_addr;
243 daddr.addr.a4 = inet_rsk(req)->ir_rmt_addr;
244 hash = (__force unsigned int) daddr.addr.a4;
245 break;
246 #if IS_ENABLED(CONFIG_IPV6)
247 case AF_INET6:
248 *(struct in6_addr *)saddr.addr.a6 = inet_rsk(req)->ir_v6_loc_addr;
249 *(struct in6_addr *)daddr.addr.a6 = inet_rsk(req)->ir_v6_rmt_addr;
250 hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr);
251 break;
252 #endif
253 default:
254 return NULL;
255 }
256
257 net = dev_net(dst->dev);
258 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
259
260 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
261 tm = rcu_dereference(tm->tcpm_next)) {
262 if (addr_same(&tm->tcpm_saddr, &saddr) &&
263 addr_same(&tm->tcpm_daddr, &daddr))
264 break;
265 }
266 tcpm_check_stamp(tm, dst);
267 return tm;
268 }
269
270 static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock *tw)
271 {
272 struct tcp_metrics_block *tm;
273 struct inetpeer_addr saddr, daddr;
274 unsigned int hash;
275 struct net *net;
276
277 saddr.family = tw->tw_family;
278 daddr.family = tw->tw_family;
279 switch (daddr.family) {
280 case AF_INET:
281 saddr.addr.a4 = tw->tw_rcv_saddr;
282 daddr.addr.a4 = tw->tw_daddr;
283 hash = (__force unsigned int) daddr.addr.a4;
284 break;
285 #if IS_ENABLED(CONFIG_IPV6)
286 case AF_INET6:
287 *(struct in6_addr *)saddr.addr.a6 = tw->tw_v6_rcv_saddr;
288 *(struct in6_addr *)daddr.addr.a6 = tw->tw_v6_daddr;
289 hash = ipv6_addr_hash(&tw->tw_v6_daddr);
290 break;
291 #endif
292 default:
293 return NULL;
294 }
295
296 net = twsk_net(tw);
297 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
298
299 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
300 tm = rcu_dereference(tm->tcpm_next)) {
301 if (addr_same(&tm->tcpm_saddr, &saddr) &&
302 addr_same(&tm->tcpm_daddr, &daddr))
303 break;
304 }
305 return tm;
306 }
307
308 static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk,
309 struct dst_entry *dst,
310 bool create)
311 {
312 struct tcp_metrics_block *tm;
313 struct inetpeer_addr saddr, daddr;
314 unsigned int hash;
315 struct net *net;
316
317 saddr.family = sk->sk_family;
318 daddr.family = sk->sk_family;
319 switch (daddr.family) {
320 case AF_INET:
321 saddr.addr.a4 = inet_sk(sk)->inet_saddr;
322 daddr.addr.a4 = inet_sk(sk)->inet_daddr;
323 hash = (__force unsigned int) daddr.addr.a4;
324 break;
325 #if IS_ENABLED(CONFIG_IPV6)
326 case AF_INET6:
327 *(struct in6_addr *)saddr.addr.a6 = sk->sk_v6_rcv_saddr;
328 *(struct in6_addr *)daddr.addr.a6 = sk->sk_v6_daddr;
329 hash = ipv6_addr_hash(&sk->sk_v6_daddr);
330 break;
331 #endif
332 default:
333 return NULL;
334 }
335
336 net = dev_net(dst->dev);
337 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
338
339 tm = __tcp_get_metrics(&saddr, &daddr, net, hash);
340 if (tm == TCP_METRICS_RECLAIM_PTR)
341 tm = NULL;
342 if (!tm && create)
343 tm = tcpm_new(dst, &saddr, &daddr, hash);
344 else
345 tcpm_check_stamp(tm, dst);
346
347 return tm;
348 }
349
350 /* Save metrics learned by this TCP session. This function is called
351 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT
352 * or goes from LAST-ACK to CLOSE.
353 */
354 void tcp_update_metrics(struct sock *sk)
355 {
356 const struct inet_connection_sock *icsk = inet_csk(sk);
357 struct dst_entry *dst = __sk_dst_get(sk);
358 struct tcp_sock *tp = tcp_sk(sk);
359 struct tcp_metrics_block *tm;
360 unsigned long rtt;
361 u32 val;
362 int m;
363
364 if (sysctl_tcp_nometrics_save || !dst)
365 return;
366
367 if (dst->flags & DST_HOST)
368 dst_confirm(dst);
369
370 rcu_read_lock();
371 if (icsk->icsk_backoff || !tp->srtt) {
372 /* This session failed to estimate rtt. Why?
373 * Probably, no packets returned in time. Reset our
374 * results.
375 */
376 tm = tcp_get_metrics(sk, dst, false);
377 if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT))
378 tcp_metric_set(tm, TCP_METRIC_RTT, 0);
379 goto out_unlock;
380 } else
381 tm = tcp_get_metrics(sk, dst, true);
382
383 if (!tm)
384 goto out_unlock;
385
386 rtt = tcp_metric_get_jiffies(tm, TCP_METRIC_RTT);
387 m = rtt - tp->srtt;
388
389 /* If newly calculated rtt larger than stored one, store new
390 * one. Otherwise, use EWMA. Remember, rtt overestimation is
391 * always better than underestimation.
392 */
393 if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) {
394 if (m <= 0)
395 rtt = tp->srtt;
396 else
397 rtt -= (m >> 3);
398 tcp_metric_set_msecs(tm, TCP_METRIC_RTT, rtt);
399 }
400
401 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) {
402 unsigned long var;
403
404 if (m < 0)
405 m = -m;
406
407 /* Scale deviation to rttvar fixed point */
408 m >>= 1;
409 if (m < tp->mdev)
410 m = tp->mdev;
411
412 var = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR);
413 if (m >= var)
414 var = m;
415 else
416 var -= (var - m) >> 2;
417
418 tcp_metric_set_msecs(tm, TCP_METRIC_RTTVAR, var);
419 }
420
421 if (tcp_in_initial_slowstart(tp)) {
422 /* Slow start still did not finish. */
423 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
424 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
425 if (val && (tp->snd_cwnd >> 1) > val)
426 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
427 tp->snd_cwnd >> 1);
428 }
429 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
430 val = tcp_metric_get(tm, TCP_METRIC_CWND);
431 if (tp->snd_cwnd > val)
432 tcp_metric_set(tm, TCP_METRIC_CWND,
433 tp->snd_cwnd);
434 }
435 } else if (tp->snd_cwnd > tp->snd_ssthresh &&
436 icsk->icsk_ca_state == TCP_CA_Open) {
437 /* Cong. avoidance phase, cwnd is reliable. */
438 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH))
439 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
440 max(tp->snd_cwnd >> 1, tp->snd_ssthresh));
441 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
442 val = tcp_metric_get(tm, TCP_METRIC_CWND);
443 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1);
444 }
445 } else {
446 /* Else slow start did not finish, cwnd is non-sense,
447 * ssthresh may be also invalid.
448 */
449 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
450 val = tcp_metric_get(tm, TCP_METRIC_CWND);
451 tcp_metric_set(tm, TCP_METRIC_CWND,
452 (val + tp->snd_ssthresh) >> 1);
453 }
454 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
455 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
456 if (val && tp->snd_ssthresh > val)
457 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
458 tp->snd_ssthresh);
459 }
460 if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) {
461 val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
462 if (val < tp->reordering &&
463 tp->reordering != sysctl_tcp_reordering)
464 tcp_metric_set(tm, TCP_METRIC_REORDERING,
465 tp->reordering);
466 }
467 }
468 tm->tcpm_stamp = jiffies;
469 out_unlock:
470 rcu_read_unlock();
471 }
472
473 /* Initialize metrics on socket. */
474
475 void tcp_init_metrics(struct sock *sk)
476 {
477 struct dst_entry *dst = __sk_dst_get(sk);
478 struct tcp_sock *tp = tcp_sk(sk);
479 struct tcp_metrics_block *tm;
480 u32 val, crtt = 0; /* cached RTT scaled by 8 */
481
482 if (dst == NULL)
483 goto reset;
484
485 dst_confirm(dst);
486
487 rcu_read_lock();
488 tm = tcp_get_metrics(sk, dst, true);
489 if (!tm) {
490 rcu_read_unlock();
491 goto reset;
492 }
493
494 if (tcp_metric_locked(tm, TCP_METRIC_CWND))
495 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND);
496
497 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
498 if (val) {
499 tp->snd_ssthresh = val;
500 if (tp->snd_ssthresh > tp->snd_cwnd_clamp)
501 tp->snd_ssthresh = tp->snd_cwnd_clamp;
502 } else {
503 /* ssthresh may have been reduced unnecessarily during.
504 * 3WHS. Restore it back to its initial default.
505 */
506 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
507 }
508 val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
509 if (val && tp->reordering != val) {
510 tcp_disable_fack(tp);
511 tcp_disable_early_retrans(tp);
512 tp->reordering = val;
513 }
514
515 crtt = tcp_metric_get_jiffies(tm, TCP_METRIC_RTT);
516 rcu_read_unlock();
517 reset:
518 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal
519 * to seed the RTO for later data packets because SYN packets are
520 * small. Use the per-dst cached values to seed the RTO but keep
521 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar).
522 * Later the RTO will be updated immediately upon obtaining the first
523 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only
524 * influences the first RTO but not later RTT estimation.
525 *
526 * But if RTT is not available from the SYN (due to retransmits or
527 * syn cookies) or the cache, force a conservative 3secs timeout.
528 *
529 * A bit of theory. RTT is time passed after "normal" sized packet
530 * is sent until it is ACKed. In normal circumstances sending small
531 * packets force peer to delay ACKs and calculation is correct too.
532 * The algorithm is adaptive and, provided we follow specs, it
533 * NEVER underestimate RTT. BUT! If peer tries to make some clever
534 * tricks sort of "quick acks" for time long enough to decrease RTT
535 * to low value, and then abruptly stops to do it and starts to delay
536 * ACKs, wait for troubles.
537 */
538 if (crtt > tp->srtt) {
539 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */
540 crtt >>= 3;
541 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk));
542 } else if (tp->srtt == 0) {
543 /* RFC6298: 5.7 We've failed to get a valid RTT sample from
544 * 3WHS. This is most likely due to retransmission,
545 * including spurious one. Reset the RTO back to 3secs
546 * from the more aggressive 1sec to avoid more spurious
547 * retransmission.
548 */
549 tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK;
550 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK;
551 }
552 /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been
553 * retransmitted. In light of RFC6298 more aggressive 1sec
554 * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK
555 * retransmission has occurred.
556 */
557 if (tp->total_retrans > 1)
558 tp->snd_cwnd = 1;
559 else
560 tp->snd_cwnd = tcp_init_cwnd(tp, dst);
561 tp->snd_cwnd_stamp = tcp_time_stamp;
562 }
563
564 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check)
565 {
566 struct tcp_metrics_block *tm;
567 bool ret;
568
569 if (!dst)
570 return false;
571
572 rcu_read_lock();
573 tm = __tcp_get_metrics_req(req, dst);
574 if (paws_check) {
575 if (tm &&
576 (u32)get_seconds() - tm->tcpm_ts_stamp < TCP_PAWS_MSL &&
577 (s32)(tm->tcpm_ts - req->ts_recent) > TCP_PAWS_WINDOW)
578 ret = false;
579 else
580 ret = true;
581 } else {
582 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT) && tm->tcpm_ts_stamp)
583 ret = true;
584 else
585 ret = false;
586 }
587 rcu_read_unlock();
588
589 return ret;
590 }
591 EXPORT_SYMBOL_GPL(tcp_peer_is_proven);
592
593 void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst)
594 {
595 struct tcp_metrics_block *tm;
596
597 rcu_read_lock();
598 tm = tcp_get_metrics(sk, dst, true);
599 if (tm) {
600 struct tcp_sock *tp = tcp_sk(sk);
601
602 if ((u32)get_seconds() - tm->tcpm_ts_stamp <= TCP_PAWS_MSL) {
603 tp->rx_opt.ts_recent_stamp = tm->tcpm_ts_stamp;
604 tp->rx_opt.ts_recent = tm->tcpm_ts;
605 }
606 }
607 rcu_read_unlock();
608 }
609 EXPORT_SYMBOL_GPL(tcp_fetch_timewait_stamp);
610
611 /* VJ's idea. Save last timestamp seen from this destination and hold
612 * it at least for normal timewait interval to use for duplicate
613 * segment detection in subsequent connections, before they enter
614 * synchronized state.
615 */
616 bool tcp_remember_stamp(struct sock *sk)
617 {
618 struct dst_entry *dst = __sk_dst_get(sk);
619 bool ret = false;
620
621 if (dst) {
622 struct tcp_metrics_block *tm;
623
624 rcu_read_lock();
625 tm = tcp_get_metrics(sk, dst, true);
626 if (tm) {
627 struct tcp_sock *tp = tcp_sk(sk);
628
629 if ((s32)(tm->tcpm_ts - tp->rx_opt.ts_recent) <= 0 ||
630 ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL &&
631 tm->tcpm_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) {
632 tm->tcpm_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp;
633 tm->tcpm_ts = tp->rx_opt.ts_recent;
634 }
635 ret = true;
636 }
637 rcu_read_unlock();
638 }
639 return ret;
640 }
641
642 bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw)
643 {
644 struct tcp_metrics_block *tm;
645 bool ret = false;
646
647 rcu_read_lock();
648 tm = __tcp_get_metrics_tw(tw);
649 if (tm) {
650 const struct tcp_timewait_sock *tcptw;
651 struct sock *sk = (struct sock *) tw;
652
653 tcptw = tcp_twsk(sk);
654 if ((s32)(tm->tcpm_ts - tcptw->tw_ts_recent) <= 0 ||
655 ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL &&
656 tm->tcpm_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) {
657 tm->tcpm_ts_stamp = (u32)tcptw->tw_ts_recent_stamp;
658 tm->tcpm_ts = tcptw->tw_ts_recent;
659 }
660 ret = true;
661 }
662 rcu_read_unlock();
663
664 return ret;
665 }
666
667 static DEFINE_SEQLOCK(fastopen_seqlock);
668
669 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
670 struct tcp_fastopen_cookie *cookie,
671 int *syn_loss, unsigned long *last_syn_loss)
672 {
673 struct tcp_metrics_block *tm;
674
675 rcu_read_lock();
676 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false);
677 if (tm) {
678 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
679 unsigned int seq;
680
681 do {
682 seq = read_seqbegin(&fastopen_seqlock);
683 if (tfom->mss)
684 *mss = tfom->mss;
685 *cookie = tfom->cookie;
686 *syn_loss = tfom->syn_loss;
687 *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0;
688 } while (read_seqretry(&fastopen_seqlock, seq));
689 }
690 rcu_read_unlock();
691 }
692
693 void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
694 struct tcp_fastopen_cookie *cookie, bool syn_lost)
695 {
696 struct dst_entry *dst = __sk_dst_get(sk);
697 struct tcp_metrics_block *tm;
698
699 if (!dst)
700 return;
701 rcu_read_lock();
702 tm = tcp_get_metrics(sk, dst, true);
703 if (tm) {
704 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
705
706 write_seqlock_bh(&fastopen_seqlock);
707 if (mss)
708 tfom->mss = mss;
709 if (cookie && cookie->len > 0)
710 tfom->cookie = *cookie;
711 if (syn_lost) {
712 ++tfom->syn_loss;
713 tfom->last_syn_loss = jiffies;
714 } else
715 tfom->syn_loss = 0;
716 write_sequnlock_bh(&fastopen_seqlock);
717 }
718 rcu_read_unlock();
719 }
720
721 static struct genl_family tcp_metrics_nl_family = {
722 .id = GENL_ID_GENERATE,
723 .hdrsize = 0,
724 .name = TCP_METRICS_GENL_NAME,
725 .version = TCP_METRICS_GENL_VERSION,
726 .maxattr = TCP_METRICS_ATTR_MAX,
727 .netnsok = true,
728 };
729
730 static struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = {
731 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, },
732 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY,
733 .len = sizeof(struct in6_addr), },
734 /* Following attributes are not received for GET/DEL,
735 * we keep them for reference
736 */
737 #if 0
738 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, },
739 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, },
740 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, },
741 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, },
742 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, },
743 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, },
744 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, },
745 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY,
746 .len = TCP_FASTOPEN_COOKIE_MAX, },
747 #endif
748 };
749
750 /* Add attributes, caller cancels its header on failure */
751 static int tcp_metrics_fill_info(struct sk_buff *msg,
752 struct tcp_metrics_block *tm)
753 {
754 struct nlattr *nest;
755 int i;
756
757 switch (tm->tcpm_daddr.family) {
758 case AF_INET:
759 if (nla_put_be32(msg, TCP_METRICS_ATTR_ADDR_IPV4,
760 tm->tcpm_daddr.addr.a4) < 0)
761 goto nla_put_failure;
762 if (nla_put_be32(msg, TCP_METRICS_ATTR_SADDR_IPV4,
763 tm->tcpm_saddr.addr.a4) < 0)
764 goto nla_put_failure;
765 break;
766 case AF_INET6:
767 if (nla_put(msg, TCP_METRICS_ATTR_ADDR_IPV6, 16,
768 tm->tcpm_daddr.addr.a6) < 0)
769 goto nla_put_failure;
770 if (nla_put(msg, TCP_METRICS_ATTR_SADDR_IPV6, 16,
771 tm->tcpm_saddr.addr.a6) < 0)
772 goto nla_put_failure;
773 break;
774 default:
775 return -EAFNOSUPPORT;
776 }
777
778 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE,
779 jiffies - tm->tcpm_stamp) < 0)
780 goto nla_put_failure;
781 if (tm->tcpm_ts_stamp) {
782 if (nla_put_s32(msg, TCP_METRICS_ATTR_TW_TS_STAMP,
783 (s32) (get_seconds() - tm->tcpm_ts_stamp)) < 0)
784 goto nla_put_failure;
785 if (nla_put_u32(msg, TCP_METRICS_ATTR_TW_TSVAL,
786 tm->tcpm_ts) < 0)
787 goto nla_put_failure;
788 }
789
790 {
791 int n = 0;
792
793 nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS);
794 if (!nest)
795 goto nla_put_failure;
796 for (i = 0; i < TCP_METRIC_MAX + 1; i++) {
797 if (!tm->tcpm_vals[i])
798 continue;
799 if (nla_put_u32(msg, i + 1, tm->tcpm_vals[i]) < 0)
800 goto nla_put_failure;
801 n++;
802 }
803 if (n)
804 nla_nest_end(msg, nest);
805 else
806 nla_nest_cancel(msg, nest);
807 }
808
809 {
810 struct tcp_fastopen_metrics tfom_copy[1], *tfom;
811 unsigned int seq;
812
813 do {
814 seq = read_seqbegin(&fastopen_seqlock);
815 tfom_copy[0] = tm->tcpm_fastopen;
816 } while (read_seqretry(&fastopen_seqlock, seq));
817
818 tfom = tfom_copy;
819 if (tfom->mss &&
820 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS,
821 tfom->mss) < 0)
822 goto nla_put_failure;
823 if (tfom->syn_loss &&
824 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS,
825 tfom->syn_loss) < 0 ||
826 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS,
827 jiffies - tfom->last_syn_loss) < 0))
828 goto nla_put_failure;
829 if (tfom->cookie.len > 0 &&
830 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE,
831 tfom->cookie.len, tfom->cookie.val) < 0)
832 goto nla_put_failure;
833 }
834
835 return 0;
836
837 nla_put_failure:
838 return -EMSGSIZE;
839 }
840
841 static int tcp_metrics_dump_info(struct sk_buff *skb,
842 struct netlink_callback *cb,
843 struct tcp_metrics_block *tm)
844 {
845 void *hdr;
846
847 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
848 &tcp_metrics_nl_family, NLM_F_MULTI,
849 TCP_METRICS_CMD_GET);
850 if (!hdr)
851 return -EMSGSIZE;
852
853 if (tcp_metrics_fill_info(skb, tm) < 0)
854 goto nla_put_failure;
855
856 return genlmsg_end(skb, hdr);
857
858 nla_put_failure:
859 genlmsg_cancel(skb, hdr);
860 return -EMSGSIZE;
861 }
862
863 static int tcp_metrics_nl_dump(struct sk_buff *skb,
864 struct netlink_callback *cb)
865 {
866 struct net *net = sock_net(skb->sk);
867 unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log;
868 unsigned int row, s_row = cb->args[0];
869 int s_col = cb->args[1], col = s_col;
870
871 for (row = s_row; row < max_rows; row++, s_col = 0) {
872 struct tcp_metrics_block *tm;
873 struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash + row;
874
875 rcu_read_lock();
876 for (col = 0, tm = rcu_dereference(hb->chain); tm;
877 tm = rcu_dereference(tm->tcpm_next), col++) {
878 if (col < s_col)
879 continue;
880 if (tcp_metrics_dump_info(skb, cb, tm) < 0) {
881 rcu_read_unlock();
882 goto done;
883 }
884 }
885 rcu_read_unlock();
886 }
887
888 done:
889 cb->args[0] = row;
890 cb->args[1] = col;
891 return skb->len;
892 }
893
894 static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
895 unsigned int *hash, int optional, int v4, int v6)
896 {
897 struct nlattr *a;
898
899 a = info->attrs[v4];
900 if (a) {
901 addr->family = AF_INET;
902 addr->addr.a4 = nla_get_be32(a);
903 if (hash)
904 *hash = (__force unsigned int) addr->addr.a4;
905 return 0;
906 }
907 a = info->attrs[v6];
908 if (a) {
909 if (nla_len(a) != sizeof(struct in6_addr))
910 return -EINVAL;
911 addr->family = AF_INET6;
912 memcpy(addr->addr.a6, nla_data(a), sizeof(addr->addr.a6));
913 if (hash)
914 *hash = ipv6_addr_hash((struct in6_addr *) addr->addr.a6);
915 return 0;
916 }
917 return optional ? 1 : -EAFNOSUPPORT;
918 }
919
920 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
921 unsigned int *hash, int optional)
922 {
923 return __parse_nl_addr(info, addr, hash, optional,
924 TCP_METRICS_ATTR_ADDR_IPV4,
925 TCP_METRICS_ATTR_ADDR_IPV6);
926 }
927
928 static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr)
929 {
930 return __parse_nl_addr(info, addr, NULL, 0,
931 TCP_METRICS_ATTR_SADDR_IPV4,
932 TCP_METRICS_ATTR_SADDR_IPV6);
933 }
934
935 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
936 {
937 struct tcp_metrics_block *tm;
938 struct inetpeer_addr saddr, daddr;
939 unsigned int hash;
940 struct sk_buff *msg;
941 struct net *net = genl_info_net(info);
942 void *reply;
943 int ret;
944 bool src = true;
945
946 ret = parse_nl_addr(info, &daddr, &hash, 0);
947 if (ret < 0)
948 return ret;
949
950 ret = parse_nl_saddr(info, &saddr);
951 if (ret < 0)
952 src = false;
953
954 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
955 if (!msg)
956 return -ENOMEM;
957
958 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0,
959 info->genlhdr->cmd);
960 if (!reply)
961 goto nla_put_failure;
962
963 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
964 ret = -ESRCH;
965 rcu_read_lock();
966 for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
967 tm = rcu_dereference(tm->tcpm_next)) {
968 if (addr_same(&tm->tcpm_daddr, &daddr) &&
969 (!src || addr_same(&tm->tcpm_saddr, &saddr))) {
970 ret = tcp_metrics_fill_info(msg, tm);
971 break;
972 }
973 }
974 rcu_read_unlock();
975 if (ret < 0)
976 goto out_free;
977
978 genlmsg_end(msg, reply);
979 return genlmsg_reply(msg, info);
980
981 nla_put_failure:
982 ret = -EMSGSIZE;
983
984 out_free:
985 nlmsg_free(msg);
986 return ret;
987 }
988
989 #define deref_locked_genl(p) \
990 rcu_dereference_protected(p, lockdep_genl_is_held() && \
991 lockdep_is_held(&tcp_metrics_lock))
992
993 #define deref_genl(p) rcu_dereference_protected(p, lockdep_genl_is_held())
994
995 static int tcp_metrics_flush_all(struct net *net)
996 {
997 unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log;
998 struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash;
999 struct tcp_metrics_block *tm;
1000 unsigned int row;
1001
1002 for (row = 0; row < max_rows; row++, hb++) {
1003 spin_lock_bh(&tcp_metrics_lock);
1004 tm = deref_locked_genl(hb->chain);
1005 if (tm)
1006 hb->chain = NULL;
1007 spin_unlock_bh(&tcp_metrics_lock);
1008 while (tm) {
1009 struct tcp_metrics_block *next;
1010
1011 next = deref_genl(tm->tcpm_next);
1012 kfree_rcu(tm, rcu_head);
1013 tm = next;
1014 }
1015 }
1016 return 0;
1017 }
1018
1019 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info)
1020 {
1021 struct tcpm_hash_bucket *hb;
1022 struct tcp_metrics_block *tm, *tmlist = NULL;
1023 struct tcp_metrics_block __rcu **pp;
1024 struct inetpeer_addr saddr, daddr;
1025 unsigned int hash;
1026 struct net *net = genl_info_net(info);
1027 int ret;
1028 bool src = true;
1029
1030 ret = parse_nl_addr(info, &daddr, &hash, 1);
1031 if (ret < 0)
1032 return ret;
1033 if (ret > 0)
1034 return tcp_metrics_flush_all(net);
1035 ret = parse_nl_saddr(info, &saddr);
1036 if (ret < 0)
1037 src = false;
1038
1039 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
1040 hb = net->ipv4.tcp_metrics_hash + hash;
1041 pp = &hb->chain;
1042 spin_lock_bh(&tcp_metrics_lock);
1043 for (tm = deref_locked_genl(*pp); tm; tm = deref_locked_genl(*pp)) {
1044 if (addr_same(&tm->tcpm_daddr, &daddr) &&
1045 (!src || addr_same(&tm->tcpm_saddr, &saddr))) {
1046 *pp = tm->tcpm_next;
1047 tm->tcpm_next = tmlist;
1048 tmlist = tm;
1049 } else {
1050 pp = &tm->tcpm_next;
1051 }
1052 }
1053 spin_unlock_bh(&tcp_metrics_lock);
1054 if (!tmlist)
1055 return -ESRCH;
1056 for (tm = tmlist; tm; tm = tmlist) {
1057 tmlist = tm->tcpm_next;
1058 kfree_rcu(tm, rcu_head);
1059 }
1060 return 0;
1061 }
1062
1063 static const struct genl_ops tcp_metrics_nl_ops[] = {
1064 {
1065 .cmd = TCP_METRICS_CMD_GET,
1066 .doit = tcp_metrics_nl_cmd_get,
1067 .dumpit = tcp_metrics_nl_dump,
1068 .policy = tcp_metrics_nl_policy,
1069 .flags = GENL_ADMIN_PERM,
1070 },
1071 {
1072 .cmd = TCP_METRICS_CMD_DEL,
1073 .doit = tcp_metrics_nl_cmd_del,
1074 .policy = tcp_metrics_nl_policy,
1075 .flags = GENL_ADMIN_PERM,
1076 },
1077 };
1078
1079 static unsigned int tcpmhash_entries;
1080 static int __init set_tcpmhash_entries(char *str)
1081 {
1082 ssize_t ret;
1083
1084 if (!str)
1085 return 0;
1086
1087 ret = kstrtouint(str, 0, &tcpmhash_entries);
1088 if (ret)
1089 return 0;
1090
1091 return 1;
1092 }
1093 __setup("tcpmhash_entries=", set_tcpmhash_entries);
1094
1095 static int __net_init tcp_net_metrics_init(struct net *net)
1096 {
1097 size_t size;
1098 unsigned int slots;
1099
1100 slots = tcpmhash_entries;
1101 if (!slots) {
1102 if (totalram_pages >= 128 * 1024)
1103 slots = 16 * 1024;
1104 else
1105 slots = 8 * 1024;
1106 }
1107
1108 net->ipv4.tcp_metrics_hash_log = order_base_2(slots);
1109 size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log;
1110
1111 net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
1112 if (!net->ipv4.tcp_metrics_hash)
1113 net->ipv4.tcp_metrics_hash = vzalloc(size);
1114
1115 if (!net->ipv4.tcp_metrics_hash)
1116 return -ENOMEM;
1117
1118 return 0;
1119 }
1120
1121 static void __net_exit tcp_net_metrics_exit(struct net *net)
1122 {
1123 unsigned int i;
1124
1125 for (i = 0; i < (1U << net->ipv4.tcp_metrics_hash_log) ; i++) {
1126 struct tcp_metrics_block *tm, *next;
1127
1128 tm = rcu_dereference_protected(net->ipv4.tcp_metrics_hash[i].chain, 1);
1129 while (tm) {
1130 next = rcu_dereference_protected(tm->tcpm_next, 1);
1131 kfree(tm);
1132 tm = next;
1133 }
1134 }
1135 if (is_vmalloc_addr(net->ipv4.tcp_metrics_hash))
1136 vfree(net->ipv4.tcp_metrics_hash);
1137 else
1138 kfree(net->ipv4.tcp_metrics_hash);
1139 }
1140
1141 static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
1142 .init = tcp_net_metrics_init,
1143 .exit = tcp_net_metrics_exit,
1144 };
1145
1146 void __init tcp_metrics_init(void)
1147 {
1148 int ret;
1149
1150 ret = register_pernet_subsys(&tcp_net_metrics_ops);
1151 if (ret < 0)
1152 goto cleanup;
1153 ret = genl_register_family_with_ops(&tcp_metrics_nl_family,
1154 tcp_metrics_nl_ops);
1155 if (ret < 0)
1156 goto cleanup_subsys;
1157 return;
1158
1159 cleanup_subsys:
1160 unregister_pernet_subsys(&tcp_net_metrics_ops);
1161
1162 cleanup:
1163 return;
1164 }
Linux kernel - Deliverables
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