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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 | { |
101 | u32 val; |
102 | |
103 | tm->tcpm_stamp = jiffies; |
104 | |
105 | val = 0; |
106 | if (dst_metric_locked(dst, RTAX_RTT)) |
107 | val |= 1 << TCP_METRIC_RTT; |
108 | if (dst_metric_locked(dst, RTAX_RTTVAR)) |
109 | val |= 1 << TCP_METRIC_RTTVAR; |
110 | if (dst_metric_locked(dst, RTAX_SSTHRESH)) |
111 | val |= 1 << TCP_METRIC_SSTHRESH; |
112 | if (dst_metric_locked(dst, RTAX_CWND)) |
113 | val |= 1 << TCP_METRIC_CWND; |
114 | if (dst_metric_locked(dst, RTAX_REORDERING)) |
115 | val |= 1 << TCP_METRIC_REORDERING; |
116 | tm->tcpm_lock = val; |
117 | |
118 | tm->tcpm_vals[TCP_METRIC_RTT] = dst_metric_raw(dst, RTAX_RTT); |
119 | tm->tcpm_vals[TCP_METRIC_RTTVAR] = dst_metric_raw(dst, RTAX_RTTVAR); |
120 | tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); |
121 | tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); |
122 | tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); |
123 | tm->tcpm_ts = 0; |
124 | tm->tcpm_ts_stamp = 0; |
125 | tm->tcpm_fastopen.mss = 0; |
126 | tm->tcpm_fastopen.syn_loss = 0; |
127 | tm->tcpm_fastopen.cookie.len = 0; |
128 | } |
129 | |
130 | static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, |
131 | struct inetpeer_addr *addr, |
132 | unsigned int hash, |
133 | bool reclaim) |
134 | { |
135 | struct tcp_metrics_block *tm; |
136 | struct net *net; |
137 | |
138 | spin_lock_bh(&tcp_metrics_lock); |
139 | net = dev_net(dst->dev); |
140 | if (unlikely(reclaim)) { |
141 | struct tcp_metrics_block *oldest; |
142 | |
143 | oldest = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); |
144 | for (tm = rcu_dereference(oldest->tcpm_next); tm; |
145 | tm = rcu_dereference(tm->tcpm_next)) { |
146 | if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp)) |
147 | oldest = tm; |
148 | } |
149 | tm = oldest; |
150 | } else { |
151 | tm = kmalloc(sizeof(*tm), GFP_ATOMIC); |
152 | if (!tm) |
153 | goto out_unlock; |
154 | } |
155 | tm->tcpm_addr = *addr; |
156 | |
157 | tcpm_suck_dst(tm, dst); |
158 | |
159 | if (likely(!reclaim)) { |
160 | tm->tcpm_next = net->ipv4.tcp_metrics_hash[hash].chain; |
161 | rcu_assign_pointer(net->ipv4.tcp_metrics_hash[hash].chain, tm); |
162 | } |
163 | |
164 | out_unlock: |
165 | spin_unlock_bh(&tcp_metrics_lock); |
166 | return tm; |
167 | } |
168 | |
169 | #define TCP_METRICS_TIMEOUT (60 * 60 * HZ) |
170 | |
171 | static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst) |
172 | { |
173 | if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT))) |
174 | tcpm_suck_dst(tm, dst); |
175 | } |
176 | |
177 | #define TCP_METRICS_RECLAIM_DEPTH 5 |
178 | #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL |
179 | |
180 | static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth) |
181 | { |
182 | if (tm) |
183 | return tm; |
184 | if (depth > TCP_METRICS_RECLAIM_DEPTH) |
185 | return TCP_METRICS_RECLAIM_PTR; |
186 | return NULL; |
187 | } |
188 | |
189 | static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *addr, |
190 | struct net *net, unsigned int hash) |
191 | { |
192 | struct tcp_metrics_block *tm; |
193 | int depth = 0; |
194 | |
195 | for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; |
196 | tm = rcu_dereference(tm->tcpm_next)) { |
197 | if (addr_same(&tm->tcpm_addr, addr)) |
198 | break; |
199 | depth++; |
200 | } |
201 | return tcp_get_encode(tm, depth); |
202 | } |
203 | |
204 | static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, |
205 | struct dst_entry *dst) |
206 | { |
207 | struct tcp_metrics_block *tm; |
208 | struct inetpeer_addr addr; |
209 | unsigned int hash; |
210 | struct net *net; |
211 | |
212 | addr.family = req->rsk_ops->family; |
213 | switch (addr.family) { |
214 | case AF_INET: |
215 | addr.addr.a4 = inet_rsk(req)->rmt_addr; |
216 | hash = (__force unsigned int) addr.addr.a4; |
217 | break; |
218 | case AF_INET6: |
219 | *(struct in6_addr *)addr.addr.a6 = inet6_rsk(req)->rmt_addr; |
220 | hash = ipv6_addr_hash(&inet6_rsk(req)->rmt_addr); |
221 | break; |
222 | default: |
223 | return NULL; |
224 | } |
225 | |
226 | net = dev_net(dst->dev); |
227 | hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); |
228 | |
229 | for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; |
230 | tm = rcu_dereference(tm->tcpm_next)) { |
231 | if (addr_same(&tm->tcpm_addr, &addr)) |
232 | break; |
233 | } |
234 | tcpm_check_stamp(tm, dst); |
235 | return tm; |
236 | } |
237 | |
238 | static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock *tw) |
239 | { |
240 | struct inet6_timewait_sock *tw6; |
241 | struct tcp_metrics_block *tm; |
242 | struct inetpeer_addr addr; |
243 | unsigned int hash; |
244 | struct net *net; |
245 | |
246 | addr.family = tw->tw_family; |
247 | switch (addr.family) { |
248 | case AF_INET: |
249 | addr.addr.a4 = tw->tw_daddr; |
250 | hash = (__force unsigned int) addr.addr.a4; |
251 | break; |
252 | case AF_INET6: |
253 | tw6 = inet6_twsk((struct sock *)tw); |
254 | *(struct in6_addr *)addr.addr.a6 = tw6->tw_v6_daddr; |
255 | hash = ipv6_addr_hash(&tw6->tw_v6_daddr); |
256 | break; |
257 | default: |
258 | return NULL; |
259 | } |
260 | |
261 | net = twsk_net(tw); |
262 | hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); |
263 | |
264 | for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; |
265 | tm = rcu_dereference(tm->tcpm_next)) { |
266 | if (addr_same(&tm->tcpm_addr, &addr)) |
267 | break; |
268 | } |
269 | return tm; |
270 | } |
271 | |
272 | static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, |
273 | struct dst_entry *dst, |
274 | bool create) |
275 | { |
276 | struct tcp_metrics_block *tm; |
277 | struct inetpeer_addr addr; |
278 | unsigned int hash; |
279 | struct net *net; |
280 | bool reclaim; |
281 | |
282 | addr.family = sk->sk_family; |
283 | switch (addr.family) { |
284 | case AF_INET: |
285 | addr.addr.a4 = inet_sk(sk)->inet_daddr; |
286 | hash = (__force unsigned int) addr.addr.a4; |
287 | break; |
288 | case AF_INET6: |
289 | *(struct in6_addr *)addr.addr.a6 = inet6_sk(sk)->daddr; |
290 | hash = ipv6_addr_hash(&inet6_sk(sk)->daddr); |
291 | break; |
292 | default: |
293 | return NULL; |
294 | } |
295 | |
296 | net = dev_net(dst->dev); |
297 | hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); |
298 | |
299 | tm = __tcp_get_metrics(&addr, net, hash); |
300 | reclaim = false; |
301 | if (tm == TCP_METRICS_RECLAIM_PTR) { |
302 | reclaim = true; |
303 | tm = NULL; |
304 | } |
305 | if (!tm && create) |
306 | tm = tcpm_new(dst, &addr, hash, reclaim); |
307 | else |
308 | tcpm_check_stamp(tm, dst); |
309 | |
310 | return tm; |
311 | } |
312 | |
313 | /* Save metrics learned by this TCP session. This function is called |
314 | * only, when TCP finishes successfully i.e. when it enters TIME-WAIT |
315 | * or goes from LAST-ACK to CLOSE. |
316 | */ |
317 | void tcp_update_metrics(struct sock *sk) |
318 | { |
319 | const struct inet_connection_sock *icsk = inet_csk(sk); |
320 | struct dst_entry *dst = __sk_dst_get(sk); |
321 | struct tcp_sock *tp = tcp_sk(sk); |
322 | struct tcp_metrics_block *tm; |
323 | unsigned long rtt; |
324 | u32 val; |
325 | int m; |
326 | |
327 | if (sysctl_tcp_nometrics_save || !dst) |
328 | return; |
329 | |
330 | if (dst->flags & DST_HOST) |
331 | dst_confirm(dst); |
332 | |
333 | rcu_read_lock(); |
334 | if (icsk->icsk_backoff || !tp->srtt) { |
335 | /* This session failed to estimate rtt. Why? |
336 | * Probably, no packets returned in time. Reset our |
337 | * results. |
338 | */ |
339 | tm = tcp_get_metrics(sk, dst, false); |
340 | if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT)) |
341 | tcp_metric_set(tm, TCP_METRIC_RTT, 0); |
342 | goto out_unlock; |
343 | } else |
344 | tm = tcp_get_metrics(sk, dst, true); |
345 | |
346 | if (!tm) |
347 | goto out_unlock; |
348 | |
349 | rtt = tcp_metric_get_jiffies(tm, TCP_METRIC_RTT); |
350 | m = rtt - tp->srtt; |
351 | |
352 | /* If newly calculated rtt larger than stored one, store new |
353 | * one. Otherwise, use EWMA. Remember, rtt overestimation is |
354 | * always better than underestimation. |
355 | */ |
356 | if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) { |
357 | if (m <= 0) |
358 | rtt = tp->srtt; |
359 | else |
360 | rtt -= (m >> 3); |
361 | tcp_metric_set_msecs(tm, TCP_METRIC_RTT, rtt); |
362 | } |
363 | |
364 | if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) { |
365 | unsigned long var; |
366 | |
367 | if (m < 0) |
368 | m = -m; |
369 | |
370 | /* Scale deviation to rttvar fixed point */ |
371 | m >>= 1; |
372 | if (m < tp->mdev) |
373 | m = tp->mdev; |
374 | |
375 | var = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR); |
376 | if (m >= var) |
377 | var = m; |
378 | else |
379 | var -= (var - m) >> 2; |
380 | |
381 | tcp_metric_set_msecs(tm, TCP_METRIC_RTTVAR, var); |
382 | } |
383 | |
384 | if (tcp_in_initial_slowstart(tp)) { |
385 | /* Slow start still did not finish. */ |
386 | if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { |
387 | val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); |
388 | if (val && (tp->snd_cwnd >> 1) > val) |
389 | tcp_metric_set(tm, TCP_METRIC_SSTHRESH, |
390 | tp->snd_cwnd >> 1); |
391 | } |
392 | if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { |
393 | val = tcp_metric_get(tm, TCP_METRIC_CWND); |
394 | if (tp->snd_cwnd > val) |
395 | tcp_metric_set(tm, TCP_METRIC_CWND, |
396 | tp->snd_cwnd); |
397 | } |
398 | } else if (tp->snd_cwnd > tp->snd_ssthresh && |
399 | icsk->icsk_ca_state == TCP_CA_Open) { |
400 | /* Cong. avoidance phase, cwnd is reliable. */ |
401 | if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) |
402 | tcp_metric_set(tm, TCP_METRIC_SSTHRESH, |
403 | max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); |
404 | if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { |
405 | val = tcp_metric_get(tm, TCP_METRIC_CWND); |
406 | tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1); |
407 | } |
408 | } else { |
409 | /* Else slow start did not finish, cwnd is non-sense, |
410 | * ssthresh may be also invalid. |
411 | */ |
412 | if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { |
413 | val = tcp_metric_get(tm, TCP_METRIC_CWND); |
414 | tcp_metric_set(tm, TCP_METRIC_CWND, |
415 | (val + tp->snd_ssthresh) >> 1); |
416 | } |
417 | if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { |
418 | val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); |
419 | if (val && tp->snd_ssthresh > val) |
420 | tcp_metric_set(tm, TCP_METRIC_SSTHRESH, |
421 | tp->snd_ssthresh); |
422 | } |
423 | if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) { |
424 | val = tcp_metric_get(tm, TCP_METRIC_REORDERING); |
425 | if (val < tp->reordering && |
426 | tp->reordering != sysctl_tcp_reordering) |
427 | tcp_metric_set(tm, TCP_METRIC_REORDERING, |
428 | tp->reordering); |
429 | } |
430 | } |
431 | tm->tcpm_stamp = jiffies; |
432 | out_unlock: |
433 | rcu_read_unlock(); |
434 | } |
435 | |
436 | /* Initialize metrics on socket. */ |
437 | |
438 | void tcp_init_metrics(struct sock *sk) |
439 | { |
440 | struct dst_entry *dst = __sk_dst_get(sk); |
441 | struct tcp_sock *tp = tcp_sk(sk); |
442 | struct tcp_metrics_block *tm; |
443 | u32 val; |
444 | |
445 | if (dst == NULL) |
446 | goto reset; |
447 | |
448 | dst_confirm(dst); |
449 | |
450 | rcu_read_lock(); |
451 | tm = tcp_get_metrics(sk, dst, true); |
452 | if (!tm) { |
453 | rcu_read_unlock(); |
454 | goto reset; |
455 | } |
456 | |
457 | if (tcp_metric_locked(tm, TCP_METRIC_CWND)) |
458 | tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND); |
459 | |
460 | val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); |
461 | if (val) { |
462 | tp->snd_ssthresh = val; |
463 | if (tp->snd_ssthresh > tp->snd_cwnd_clamp) |
464 | tp->snd_ssthresh = tp->snd_cwnd_clamp; |
465 | } else { |
466 | /* ssthresh may have been reduced unnecessarily during. |
467 | * 3WHS. Restore it back to its initial default. |
468 | */ |
469 | tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; |
470 | } |
471 | val = tcp_metric_get(tm, TCP_METRIC_REORDERING); |
472 | if (val && tp->reordering != val) { |
473 | tcp_disable_fack(tp); |
474 | tcp_disable_early_retrans(tp); |
475 | tp->reordering = val; |
476 | } |
477 | |
478 | val = tcp_metric_get(tm, TCP_METRIC_RTT); |
479 | if (val == 0 || tp->srtt == 0) { |
480 | rcu_read_unlock(); |
481 | goto reset; |
482 | } |
483 | /* Initial rtt is determined from SYN,SYN-ACK. |
484 | * The segment is small and rtt may appear much |
485 | * less than real one. Use per-dst memory |
486 | * to make it more realistic. |
487 | * |
488 | * A bit of theory. RTT is time passed after "normal" sized packet |
489 | * is sent until it is ACKed. In normal circumstances sending small |
490 | * packets force peer to delay ACKs and calculation is correct too. |
491 | * The algorithm is adaptive and, provided we follow specs, it |
492 | * NEVER underestimate RTT. BUT! If peer tries to make some clever |
493 | * tricks sort of "quick acks" for time long enough to decrease RTT |
494 | * to low value, and then abruptly stops to do it and starts to delay |
495 | * ACKs, wait for troubles. |
496 | */ |
497 | val = msecs_to_jiffies(val); |
498 | if (val > tp->srtt) { |
499 | tp->srtt = val; |
500 | tp->rtt_seq = tp->snd_nxt; |
501 | } |
502 | val = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR); |
503 | if (val > tp->mdev) { |
504 | tp->mdev = val; |
505 | tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk)); |
506 | } |
507 | rcu_read_unlock(); |
508 | |
509 | tcp_set_rto(sk); |
510 | reset: |
511 | if (tp->srtt == 0) { |
512 | /* RFC6298: 5.7 We've failed to get a valid RTT sample from |
513 | * 3WHS. This is most likely due to retransmission, |
514 | * including spurious one. Reset the RTO back to 3secs |
515 | * from the more aggressive 1sec to avoid more spurious |
516 | * retransmission. |
517 | */ |
518 | tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK; |
519 | inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; |
520 | } |
521 | /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been |
522 | * retransmitted. In light of RFC6298 more aggressive 1sec |
523 | * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK |
524 | * retransmission has occurred. |
525 | */ |
526 | if (tp->total_retrans > 1) |
527 | tp->snd_cwnd = 1; |
528 | else |
529 | tp->snd_cwnd = tcp_init_cwnd(tp, dst); |
530 | tp->snd_cwnd_stamp = tcp_time_stamp; |
531 | } |
532 | |
533 | bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check) |
534 | { |
535 | struct tcp_metrics_block *tm; |
536 | bool ret; |
537 | |
538 | if (!dst) |
539 | return false; |
540 | |
541 | rcu_read_lock(); |
542 | tm = __tcp_get_metrics_req(req, dst); |
543 | if (paws_check) { |
544 | if (tm && |
545 | (u32)get_seconds() - tm->tcpm_ts_stamp < TCP_PAWS_MSL && |
546 | (s32)(tm->tcpm_ts - req->ts_recent) > TCP_PAWS_WINDOW) |
547 | ret = false; |
548 | else |
549 | ret = true; |
550 | } else { |
551 | if (tm && tcp_metric_get(tm, TCP_METRIC_RTT) && tm->tcpm_ts_stamp) |
552 | ret = true; |
553 | else |
554 | ret = false; |
555 | } |
556 | rcu_read_unlock(); |
557 | |
558 | return ret; |
559 | } |
560 | EXPORT_SYMBOL_GPL(tcp_peer_is_proven); |
561 | |
562 | void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst) |
563 | { |
564 | struct tcp_metrics_block *tm; |
565 | |
566 | rcu_read_lock(); |
567 | tm = tcp_get_metrics(sk, dst, true); |
568 | if (tm) { |
569 | struct tcp_sock *tp = tcp_sk(sk); |
570 | |
571 | if ((u32)get_seconds() - tm->tcpm_ts_stamp <= TCP_PAWS_MSL) { |
572 | tp->rx_opt.ts_recent_stamp = tm->tcpm_ts_stamp; |
573 | tp->rx_opt.ts_recent = tm->tcpm_ts; |
574 | } |
575 | } |
576 | rcu_read_unlock(); |
577 | } |
578 | EXPORT_SYMBOL_GPL(tcp_fetch_timewait_stamp); |
579 | |
580 | /* VJ's idea. Save last timestamp seen from this destination and hold |
581 | * it at least for normal timewait interval to use for duplicate |
582 | * segment detection in subsequent connections, before they enter |
583 | * synchronized state. |
584 | */ |
585 | bool tcp_remember_stamp(struct sock *sk) |
586 | { |
587 | struct dst_entry *dst = __sk_dst_get(sk); |
588 | bool ret = false; |
589 | |
590 | if (dst) { |
591 | struct tcp_metrics_block *tm; |
592 | |
593 | rcu_read_lock(); |
594 | tm = tcp_get_metrics(sk, dst, true); |
595 | if (tm) { |
596 | struct tcp_sock *tp = tcp_sk(sk); |
597 | |
598 | if ((s32)(tm->tcpm_ts - tp->rx_opt.ts_recent) <= 0 || |
599 | ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL && |
600 | tm->tcpm_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) { |
601 | tm->tcpm_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp; |
602 | tm->tcpm_ts = tp->rx_opt.ts_recent; |
603 | } |
604 | ret = true; |
605 | } |
606 | rcu_read_unlock(); |
607 | } |
608 | return ret; |
609 | } |
610 | |
611 | bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw) |
612 | { |
613 | struct tcp_metrics_block *tm; |
614 | bool ret = false; |
615 | |
616 | rcu_read_lock(); |
617 | tm = __tcp_get_metrics_tw(tw); |
618 | if (tm) { |
619 | const struct tcp_timewait_sock *tcptw; |
620 | struct sock *sk = (struct sock *) tw; |
621 | |
622 | tcptw = tcp_twsk(sk); |
623 | if ((s32)(tm->tcpm_ts - tcptw->tw_ts_recent) <= 0 || |
624 | ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL && |
625 | tm->tcpm_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) { |
626 | tm->tcpm_ts_stamp = (u32)tcptw->tw_ts_recent_stamp; |
627 | tm->tcpm_ts = tcptw->tw_ts_recent; |
628 | } |
629 | ret = true; |
630 | } |
631 | rcu_read_unlock(); |
632 | |
633 | return ret; |
634 | } |
635 | |
636 | static DEFINE_SEQLOCK(fastopen_seqlock); |
637 | |
638 | void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, |
639 | struct tcp_fastopen_cookie *cookie, |
640 | int *syn_loss, unsigned long *last_syn_loss) |
641 | { |
642 | struct tcp_metrics_block *tm; |
643 | |
644 | rcu_read_lock(); |
645 | tm = tcp_get_metrics(sk, __sk_dst_get(sk), false); |
646 | if (tm) { |
647 | struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; |
648 | unsigned int seq; |
649 | |
650 | do { |
651 | seq = read_seqbegin(&fastopen_seqlock); |
652 | if (tfom->mss) |
653 | *mss = tfom->mss; |
654 | *cookie = tfom->cookie; |
655 | *syn_loss = tfom->syn_loss; |
656 | *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0; |
657 | } while (read_seqretry(&fastopen_seqlock, seq)); |
658 | } |
659 | rcu_read_unlock(); |
660 | } |
661 | |
662 | void tcp_fastopen_cache_set(struct sock *sk, u16 mss, |
663 | struct tcp_fastopen_cookie *cookie, bool syn_lost) |
664 | { |
665 | struct tcp_metrics_block *tm; |
666 | |
667 | rcu_read_lock(); |
668 | tm = tcp_get_metrics(sk, __sk_dst_get(sk), true); |
669 | if (tm) { |
670 | struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; |
671 | |
672 | write_seqlock_bh(&fastopen_seqlock); |
673 | tfom->mss = mss; |
674 | if (cookie->len > 0) |
675 | tfom->cookie = *cookie; |
676 | if (syn_lost) { |
677 | ++tfom->syn_loss; |
678 | tfom->last_syn_loss = jiffies; |
679 | } else |
680 | tfom->syn_loss = 0; |
681 | write_sequnlock_bh(&fastopen_seqlock); |
682 | } |
683 | rcu_read_unlock(); |
684 | } |
685 | |
686 | static struct genl_family tcp_metrics_nl_family = { |
687 | .id = GENL_ID_GENERATE, |
688 | .hdrsize = 0, |
689 | .name = TCP_METRICS_GENL_NAME, |
690 | .version = TCP_METRICS_GENL_VERSION, |
691 | .maxattr = TCP_METRICS_ATTR_MAX, |
692 | .netnsok = true, |
693 | }; |
694 | |
695 | static struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = { |
696 | [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, }, |
697 | [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY, |
698 | .len = sizeof(struct in6_addr), }, |
699 | /* Following attributes are not received for GET/DEL, |
700 | * we keep them for reference |
701 | */ |
702 | #if 0 |
703 | [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, }, |
704 | [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, }, |
705 | [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, }, |
706 | [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, }, |
707 | [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, }, |
708 | [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, }, |
709 | [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, }, |
710 | [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY, |
711 | .len = TCP_FASTOPEN_COOKIE_MAX, }, |
712 | #endif |
713 | }; |
714 | |
715 | /* Add attributes, caller cancels its header on failure */ |
716 | static int tcp_metrics_fill_info(struct sk_buff *msg, |
717 | struct tcp_metrics_block *tm) |
718 | { |
719 | struct nlattr *nest; |
720 | int i; |
721 | |
722 | switch (tm->tcpm_addr.family) { |
723 | case AF_INET: |
724 | if (nla_put_be32(msg, TCP_METRICS_ATTR_ADDR_IPV4, |
725 | tm->tcpm_addr.addr.a4) < 0) |
726 | goto nla_put_failure; |
727 | break; |
728 | case AF_INET6: |
729 | if (nla_put(msg, TCP_METRICS_ATTR_ADDR_IPV6, 16, |
730 | tm->tcpm_addr.addr.a6) < 0) |
731 | goto nla_put_failure; |
732 | break; |
733 | default: |
734 | return -EAFNOSUPPORT; |
735 | } |
736 | |
737 | if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE, |
738 | jiffies - tm->tcpm_stamp) < 0) |
739 | goto nla_put_failure; |
740 | if (tm->tcpm_ts_stamp) { |
741 | if (nla_put_s32(msg, TCP_METRICS_ATTR_TW_TS_STAMP, |
742 | (s32) (get_seconds() - tm->tcpm_ts_stamp)) < 0) |
743 | goto nla_put_failure; |
744 | if (nla_put_u32(msg, TCP_METRICS_ATTR_TW_TSVAL, |
745 | tm->tcpm_ts) < 0) |
746 | goto nla_put_failure; |
747 | } |
748 | |
749 | { |
750 | int n = 0; |
751 | |
752 | nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS); |
753 | if (!nest) |
754 | goto nla_put_failure; |
755 | for (i = 0; i < TCP_METRIC_MAX + 1; i++) { |
756 | if (!tm->tcpm_vals[i]) |
757 | continue; |
758 | if (nla_put_u32(msg, i + 1, tm->tcpm_vals[i]) < 0) |
759 | goto nla_put_failure; |
760 | n++; |
761 | } |
762 | if (n) |
763 | nla_nest_end(msg, nest); |
764 | else |
765 | nla_nest_cancel(msg, nest); |
766 | } |
767 | |
768 | { |
769 | struct tcp_fastopen_metrics tfom_copy[1], *tfom; |
770 | unsigned int seq; |
771 | |
772 | do { |
773 | seq = read_seqbegin(&fastopen_seqlock); |
774 | tfom_copy[0] = tm->tcpm_fastopen; |
775 | } while (read_seqretry(&fastopen_seqlock, seq)); |
776 | |
777 | tfom = tfom_copy; |
778 | if (tfom->mss && |
779 | nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS, |
780 | tfom->mss) < 0) |
781 | goto nla_put_failure; |
782 | if (tfom->syn_loss && |
783 | (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS, |
784 | tfom->syn_loss) < 0 || |
785 | nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS, |
786 | jiffies - tfom->last_syn_loss) < 0)) |
787 | goto nla_put_failure; |
788 | if (tfom->cookie.len > 0 && |
789 | nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE, |
790 | tfom->cookie.len, tfom->cookie.val) < 0) |
791 | goto nla_put_failure; |
792 | } |
793 | |
794 | return 0; |
795 | |
796 | nla_put_failure: |
797 | return -EMSGSIZE; |
798 | } |
799 | |
800 | static int tcp_metrics_dump_info(struct sk_buff *skb, |
801 | struct netlink_callback *cb, |
802 | struct tcp_metrics_block *tm) |
803 | { |
804 | void *hdr; |
805 | |
806 | hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, |
807 | &tcp_metrics_nl_family, NLM_F_MULTI, |
808 | TCP_METRICS_CMD_GET); |
809 | if (!hdr) |
810 | return -EMSGSIZE; |
811 | |
812 | if (tcp_metrics_fill_info(skb, tm) < 0) |
813 | goto nla_put_failure; |
814 | |
815 | return genlmsg_end(skb, hdr); |
816 | |
817 | nla_put_failure: |
818 | genlmsg_cancel(skb, hdr); |
819 | return -EMSGSIZE; |
820 | } |
821 | |
822 | static int tcp_metrics_nl_dump(struct sk_buff *skb, |
823 | struct netlink_callback *cb) |
824 | { |
825 | struct net *net = sock_net(skb->sk); |
826 | unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log; |
827 | unsigned int row, s_row = cb->args[0]; |
828 | int s_col = cb->args[1], col = s_col; |
829 | |
830 | for (row = s_row; row < max_rows; row++, s_col = 0) { |
831 | struct tcp_metrics_block *tm; |
832 | struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash + row; |
833 | |
834 | rcu_read_lock(); |
835 | for (col = 0, tm = rcu_dereference(hb->chain); tm; |
836 | tm = rcu_dereference(tm->tcpm_next), col++) { |
837 | if (col < s_col) |
838 | continue; |
839 | if (tcp_metrics_dump_info(skb, cb, tm) < 0) { |
840 | rcu_read_unlock(); |
841 | goto done; |
842 | } |
843 | } |
844 | rcu_read_unlock(); |
845 | } |
846 | |
847 | done: |
848 | cb->args[0] = row; |
849 | cb->args[1] = col; |
850 | return skb->len; |
851 | } |
852 | |
853 | static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, |
854 | unsigned int *hash, int optional) |
855 | { |
856 | struct nlattr *a; |
857 | |
858 | a = info->attrs[TCP_METRICS_ATTR_ADDR_IPV4]; |
859 | if (a) { |
860 | addr->family = AF_INET; |
861 | addr->addr.a4 = nla_get_be32(a); |
862 | *hash = (__force unsigned int) addr->addr.a4; |
863 | return 0; |
864 | } |
865 | a = info->attrs[TCP_METRICS_ATTR_ADDR_IPV6]; |
866 | if (a) { |
867 | if (nla_len(a) != sizeof(struct in6_addr)) |
868 | return -EINVAL; |
869 | addr->family = AF_INET6; |
870 | memcpy(addr->addr.a6, nla_data(a), sizeof(addr->addr.a6)); |
871 | *hash = ipv6_addr_hash((struct in6_addr *) addr->addr.a6); |
872 | return 0; |
873 | } |
874 | return optional ? 1 : -EAFNOSUPPORT; |
875 | } |
876 | |
877 | static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info) |
878 | { |
879 | struct tcp_metrics_block *tm; |
880 | struct inetpeer_addr addr; |
881 | unsigned int hash; |
882 | struct sk_buff *msg; |
883 | struct net *net = genl_info_net(info); |
884 | void *reply; |
885 | int ret; |
886 | |
887 | ret = parse_nl_addr(info, &addr, &hash, 0); |
888 | if (ret < 0) |
889 | return ret; |
890 | |
891 | msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); |
892 | if (!msg) |
893 | return -ENOMEM; |
894 | |
895 | reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0, |
896 | info->genlhdr->cmd); |
897 | if (!reply) |
898 | goto nla_put_failure; |
899 | |
900 | hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); |
901 | ret = -ESRCH; |
902 | rcu_read_lock(); |
903 | for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; |
904 | tm = rcu_dereference(tm->tcpm_next)) { |
905 | if (addr_same(&tm->tcpm_addr, &addr)) { |
906 | ret = tcp_metrics_fill_info(msg, tm); |
907 | break; |
908 | } |
909 | } |
910 | rcu_read_unlock(); |
911 | if (ret < 0) |
912 | goto out_free; |
913 | |
914 | genlmsg_end(msg, reply); |
915 | return genlmsg_reply(msg, info); |
916 | |
917 | nla_put_failure: |
918 | ret = -EMSGSIZE; |
919 | |
920 | out_free: |
921 | nlmsg_free(msg); |
922 | return ret; |
923 | } |
924 | |
925 | #define deref_locked_genl(p) \ |
926 | rcu_dereference_protected(p, lockdep_genl_is_held() && \ |
927 | lockdep_is_held(&tcp_metrics_lock)) |
928 | |
929 | #define deref_genl(p) rcu_dereference_protected(p, lockdep_genl_is_held()) |
930 | |
931 | static int tcp_metrics_flush_all(struct net *net) |
932 | { |
933 | unsigned int max_rows = 1U << net->ipv4.tcp_metrics_hash_log; |
934 | struct tcpm_hash_bucket *hb = net->ipv4.tcp_metrics_hash; |
935 | struct tcp_metrics_block *tm; |
936 | unsigned int row; |
937 | |
938 | for (row = 0; row < max_rows; row++, hb++) { |
939 | spin_lock_bh(&tcp_metrics_lock); |
940 | tm = deref_locked_genl(hb->chain); |
941 | if (tm) |
942 | hb->chain = NULL; |
943 | spin_unlock_bh(&tcp_metrics_lock); |
944 | while (tm) { |
945 | struct tcp_metrics_block *next; |
946 | |
947 | next = deref_genl(tm->tcpm_next); |
948 | kfree_rcu(tm, rcu_head); |
949 | tm = next; |
950 | } |
951 | } |
952 | return 0; |
953 | } |
954 | |
955 | static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info) |
956 | { |
957 | struct tcpm_hash_bucket *hb; |
958 | struct tcp_metrics_block *tm; |
959 | struct tcp_metrics_block __rcu **pp; |
960 | struct inetpeer_addr addr; |
961 | unsigned int hash; |
962 | struct net *net = genl_info_net(info); |
963 | int ret; |
964 | |
965 | ret = parse_nl_addr(info, &addr, &hash, 1); |
966 | if (ret < 0) |
967 | return ret; |
968 | if (ret > 0) |
969 | return tcp_metrics_flush_all(net); |
970 | |
971 | hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); |
972 | hb = net->ipv4.tcp_metrics_hash + hash; |
973 | pp = &hb->chain; |
974 | spin_lock_bh(&tcp_metrics_lock); |
975 | for (tm = deref_locked_genl(*pp); tm; |
976 | pp = &tm->tcpm_next, tm = deref_locked_genl(*pp)) { |
977 | if (addr_same(&tm->tcpm_addr, &addr)) { |
978 | *pp = tm->tcpm_next; |
979 | break; |
980 | } |
981 | } |
982 | spin_unlock_bh(&tcp_metrics_lock); |
983 | if (!tm) |
984 | return -ESRCH; |
985 | kfree_rcu(tm, rcu_head); |
986 | return 0; |
987 | } |
988 | |
989 | static struct genl_ops tcp_metrics_nl_ops[] = { |
990 | { |
991 | .cmd = TCP_METRICS_CMD_GET, |
992 | .doit = tcp_metrics_nl_cmd_get, |
993 | .dumpit = tcp_metrics_nl_dump, |
994 | .policy = tcp_metrics_nl_policy, |
995 | .flags = GENL_ADMIN_PERM, |
996 | }, |
997 | { |
998 | .cmd = TCP_METRICS_CMD_DEL, |
999 | .doit = tcp_metrics_nl_cmd_del, |
1000 | .policy = tcp_metrics_nl_policy, |
1001 | .flags = GENL_ADMIN_PERM, |
1002 | }, |
1003 | }; |
1004 | |
1005 | static unsigned int tcpmhash_entries; |
1006 | static int __init set_tcpmhash_entries(char *str) |
1007 | { |
1008 | ssize_t ret; |
1009 | |
1010 | if (!str) |
1011 | return 0; |
1012 | |
1013 | ret = kstrtouint(str, 0, &tcpmhash_entries); |
1014 | if (ret) |
1015 | return 0; |
1016 | |
1017 | return 1; |
1018 | } |
1019 | __setup("tcpmhash_entries=", set_tcpmhash_entries); |
1020 | |
1021 | static int __net_init tcp_net_metrics_init(struct net *net) |
1022 | { |
1023 | size_t size; |
1024 | unsigned int slots; |
1025 | |
1026 | slots = tcpmhash_entries; |
1027 | if (!slots) { |
1028 | if (totalram_pages >= 128 * 1024) |
1029 | slots = 16 * 1024; |
1030 | else |
1031 | slots = 8 * 1024; |
1032 | } |
1033 | |
1034 | net->ipv4.tcp_metrics_hash_log = order_base_2(slots); |
1035 | size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log; |
1036 | |
1037 | net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); |
1038 | if (!net->ipv4.tcp_metrics_hash) |
1039 | net->ipv4.tcp_metrics_hash = vzalloc(size); |
1040 | |
1041 | if (!net->ipv4.tcp_metrics_hash) |
1042 | return -ENOMEM; |
1043 | |
1044 | return 0; |
1045 | } |
1046 | |
1047 | static void __net_exit tcp_net_metrics_exit(struct net *net) |
1048 | { |
1049 | unsigned int i; |
1050 | |
1051 | for (i = 0; i < (1U << net->ipv4.tcp_metrics_hash_log) ; i++) { |
1052 | struct tcp_metrics_block *tm, *next; |
1053 | |
1054 | tm = rcu_dereference_protected(net->ipv4.tcp_metrics_hash[i].chain, 1); |
1055 | while (tm) { |
1056 | next = rcu_dereference_protected(tm->tcpm_next, 1); |
1057 | kfree(tm); |
1058 | tm = next; |
1059 | } |
1060 | } |
1061 | if (is_vmalloc_addr(net->ipv4.tcp_metrics_hash)) |
1062 | vfree(net->ipv4.tcp_metrics_hash); |
1063 | else |
1064 | kfree(net->ipv4.tcp_metrics_hash); |
1065 | } |
1066 | |
1067 | static __net_initdata struct pernet_operations tcp_net_metrics_ops = { |
1068 | .init = tcp_net_metrics_init, |
1069 | .exit = tcp_net_metrics_exit, |
1070 | }; |
1071 | |
1072 | void __init tcp_metrics_init(void) |
1073 | { |
1074 | int ret; |
1075 | |
1076 | ret = register_pernet_subsys(&tcp_net_metrics_ops); |
1077 | if (ret < 0) |
1078 | goto cleanup; |
1079 | ret = genl_register_family_with_ops(&tcp_metrics_nl_family, |
1080 | tcp_metrics_nl_ops, |
1081 | ARRAY_SIZE(tcp_metrics_nl_ops)); |
1082 | if (ret < 0) |
1083 | goto cleanup_subsys; |
1084 | return; |
1085 | |
1086 | cleanup_subsys: |
1087 | unregister_pernet_subsys(&tcp_net_metrics_ops); |
1088 | |
1089 | cleanup: |
1090 | return; |
1091 | } |
1092 |
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