Commit | Line | Data |
---|---|---|
51c5d0c4 DM |
1 | #include <linux/rcupdate.h> |
2 | #include <linux/spinlock.h> | |
3 | #include <linux/jiffies.h> | |
4 | #include <linux/bootmem.h> | |
ab92bb2f | 5 | #include <linux/module.h> |
4aabd8ef | 6 | #include <linux/cache.h> |
51c5d0c4 DM |
7 | #include <linux/slab.h> |
8 | #include <linux/init.h> | |
4aabd8ef | 9 | #include <linux/tcp.h> |
5815d5e7 | 10 | #include <linux/hash.h> |
4aabd8ef DM |
11 | |
12 | #include <net/inet_connection_sock.h> | |
51c5d0c4 | 13 | #include <net/net_namespace.h> |
ab92bb2f | 14 | #include <net/request_sock.h> |
51c5d0c4 | 15 | #include <net/inetpeer.h> |
4aabd8ef | 16 | #include <net/sock.h> |
51c5d0c4 | 17 | #include <net/ipv6.h> |
4aabd8ef DM |
18 | #include <net/dst.h> |
19 | #include <net/tcp.h> | |
20 | ||
21 | int sysctl_tcp_nometrics_save __read_mostly; | |
22 | ||
51c5d0c4 DM |
23 | enum tcp_metric_index { |
24 | TCP_METRIC_RTT, | |
25 | TCP_METRIC_RTTVAR, | |
26 | TCP_METRIC_SSTHRESH, | |
27 | TCP_METRIC_CWND, | |
28 | TCP_METRIC_REORDERING, | |
29 | ||
30 | /* Always last. */ | |
31 | TCP_METRIC_MAX, | |
32 | }; | |
33 | ||
1fe4c481 YC |
34 | struct tcp_fastopen_metrics { |
35 | u16 mss; | |
aab48743 YC |
36 | u16 syn_loss:10; /* Recurring Fast Open SYN losses */ |
37 | unsigned long last_syn_loss; /* Last Fast Open SYN loss */ | |
1fe4c481 YC |
38 | struct tcp_fastopen_cookie cookie; |
39 | }; | |
40 | ||
51c5d0c4 DM |
41 | struct tcp_metrics_block { |
42 | struct tcp_metrics_block __rcu *tcpm_next; | |
43 | struct inetpeer_addr tcpm_addr; | |
44 | unsigned long tcpm_stamp; | |
81166dd6 DM |
45 | u32 tcpm_ts; |
46 | u32 tcpm_ts_stamp; | |
51c5d0c4 DM |
47 | u32 tcpm_lock; |
48 | u32 tcpm_vals[TCP_METRIC_MAX]; | |
1fe4c481 | 49 | struct tcp_fastopen_metrics tcpm_fastopen; |
51c5d0c4 DM |
50 | }; |
51 | ||
52 | static bool tcp_metric_locked(struct tcp_metrics_block *tm, | |
53 | enum tcp_metric_index idx) | |
54 | { | |
55 | return tm->tcpm_lock & (1 << idx); | |
56 | } | |
57 | ||
58 | static u32 tcp_metric_get(struct tcp_metrics_block *tm, | |
59 | enum tcp_metric_index idx) | |
60 | { | |
61 | return tm->tcpm_vals[idx]; | |
62 | } | |
63 | ||
64 | static u32 tcp_metric_get_jiffies(struct tcp_metrics_block *tm, | |
65 | enum tcp_metric_index idx) | |
66 | { | |
67 | return msecs_to_jiffies(tm->tcpm_vals[idx]); | |
68 | } | |
69 | ||
70 | static void tcp_metric_set(struct tcp_metrics_block *tm, | |
71 | enum tcp_metric_index idx, | |
72 | u32 val) | |
73 | { | |
74 | tm->tcpm_vals[idx] = val; | |
75 | } | |
76 | ||
77 | static void tcp_metric_set_msecs(struct tcp_metrics_block *tm, | |
78 | enum tcp_metric_index idx, | |
79 | u32 val) | |
80 | { | |
81 | tm->tcpm_vals[idx] = jiffies_to_msecs(val); | |
82 | } | |
83 | ||
84 | static bool addr_same(const struct inetpeer_addr *a, | |
85 | const struct inetpeer_addr *b) | |
86 | { | |
87 | const struct in6_addr *a6, *b6; | |
88 | ||
89 | if (a->family != b->family) | |
90 | return false; | |
91 | if (a->family == AF_INET) | |
92 | return a->addr.a4 == b->addr.a4; | |
93 | ||
94 | a6 = (const struct in6_addr *) &a->addr.a6[0]; | |
95 | b6 = (const struct in6_addr *) &b->addr.a6[0]; | |
96 | ||
97 | return ipv6_addr_equal(a6, b6); | |
98 | } | |
99 | ||
100 | struct tcpm_hash_bucket { | |
101 | struct tcp_metrics_block __rcu *chain; | |
102 | }; | |
103 | ||
104 | static DEFINE_SPINLOCK(tcp_metrics_lock); | |
105 | ||
106 | static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst) | |
107 | { | |
108 | u32 val; | |
109 | ||
9a0a9502 JA |
110 | tm->tcpm_stamp = jiffies; |
111 | ||
51c5d0c4 DM |
112 | val = 0; |
113 | if (dst_metric_locked(dst, RTAX_RTT)) | |
114 | val |= 1 << TCP_METRIC_RTT; | |
115 | if (dst_metric_locked(dst, RTAX_RTTVAR)) | |
116 | val |= 1 << TCP_METRIC_RTTVAR; | |
117 | if (dst_metric_locked(dst, RTAX_SSTHRESH)) | |
118 | val |= 1 << TCP_METRIC_SSTHRESH; | |
119 | if (dst_metric_locked(dst, RTAX_CWND)) | |
120 | val |= 1 << TCP_METRIC_CWND; | |
121 | if (dst_metric_locked(dst, RTAX_REORDERING)) | |
122 | val |= 1 << TCP_METRIC_REORDERING; | |
123 | tm->tcpm_lock = val; | |
124 | ||
125 | tm->tcpm_vals[TCP_METRIC_RTT] = dst_metric_raw(dst, RTAX_RTT); | |
126 | tm->tcpm_vals[TCP_METRIC_RTTVAR] = dst_metric_raw(dst, RTAX_RTTVAR); | |
127 | tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); | |
128 | tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); | |
129 | tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); | |
81166dd6 DM |
130 | tm->tcpm_ts = 0; |
131 | tm->tcpm_ts_stamp = 0; | |
1fe4c481 | 132 | tm->tcpm_fastopen.mss = 0; |
aab48743 | 133 | tm->tcpm_fastopen.syn_loss = 0; |
1fe4c481 | 134 | tm->tcpm_fastopen.cookie.len = 0; |
51c5d0c4 DM |
135 | } |
136 | ||
137 | static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, | |
138 | struct inetpeer_addr *addr, | |
139 | unsigned int hash, | |
140 | bool reclaim) | |
141 | { | |
142 | struct tcp_metrics_block *tm; | |
143 | struct net *net; | |
144 | ||
145 | spin_lock_bh(&tcp_metrics_lock); | |
146 | net = dev_net(dst->dev); | |
147 | if (unlikely(reclaim)) { | |
148 | struct tcp_metrics_block *oldest; | |
149 | ||
150 | oldest = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); | |
151 | for (tm = rcu_dereference(oldest->tcpm_next); tm; | |
152 | tm = rcu_dereference(tm->tcpm_next)) { | |
153 | if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp)) | |
154 | oldest = tm; | |
155 | } | |
156 | tm = oldest; | |
157 | } else { | |
158 | tm = kmalloc(sizeof(*tm), GFP_ATOMIC); | |
159 | if (!tm) | |
160 | goto out_unlock; | |
161 | } | |
162 | tm->tcpm_addr = *addr; | |
51c5d0c4 DM |
163 | |
164 | tcpm_suck_dst(tm, dst); | |
165 | ||
166 | if (likely(!reclaim)) { | |
167 | tm->tcpm_next = net->ipv4.tcp_metrics_hash[hash].chain; | |
168 | rcu_assign_pointer(net->ipv4.tcp_metrics_hash[hash].chain, tm); | |
169 | } | |
170 | ||
171 | out_unlock: | |
172 | spin_unlock_bh(&tcp_metrics_lock); | |
173 | return tm; | |
174 | } | |
175 | ||
176 | #define TCP_METRICS_TIMEOUT (60 * 60 * HZ) | |
177 | ||
178 | static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst) | |
179 | { | |
180 | if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT))) | |
181 | tcpm_suck_dst(tm, dst); | |
182 | } | |
183 | ||
184 | #define TCP_METRICS_RECLAIM_DEPTH 5 | |
185 | #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL | |
186 | ||
187 | static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth) | |
188 | { | |
189 | if (tm) | |
190 | return tm; | |
191 | if (depth > TCP_METRICS_RECLAIM_DEPTH) | |
192 | return TCP_METRICS_RECLAIM_PTR; | |
193 | return NULL; | |
194 | } | |
195 | ||
196 | static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *addr, | |
197 | struct net *net, unsigned int hash) | |
198 | { | |
199 | struct tcp_metrics_block *tm; | |
200 | int depth = 0; | |
201 | ||
202 | for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; | |
203 | tm = rcu_dereference(tm->tcpm_next)) { | |
204 | if (addr_same(&tm->tcpm_addr, addr)) | |
205 | break; | |
206 | depth++; | |
207 | } | |
208 | return tcp_get_encode(tm, depth); | |
209 | } | |
210 | ||
211 | static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, | |
212 | struct dst_entry *dst) | |
213 | { | |
214 | struct tcp_metrics_block *tm; | |
215 | struct inetpeer_addr addr; | |
216 | unsigned int hash; | |
217 | struct net *net; | |
218 | ||
219 | addr.family = req->rsk_ops->family; | |
220 | switch (addr.family) { | |
221 | case AF_INET: | |
222 | addr.addr.a4 = inet_rsk(req)->rmt_addr; | |
223 | hash = (__force unsigned int) addr.addr.a4; | |
224 | break; | |
225 | case AF_INET6: | |
226 | *(struct in6_addr *)addr.addr.a6 = inet6_rsk(req)->rmt_addr; | |
ddbe5032 | 227 | hash = ipv6_addr_hash(&inet6_rsk(req)->rmt_addr); |
51c5d0c4 DM |
228 | break; |
229 | default: | |
230 | return NULL; | |
231 | } | |
232 | ||
51c5d0c4 | 233 | net = dev_net(dst->dev); |
5815d5e7 | 234 | hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); |
51c5d0c4 DM |
235 | |
236 | for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; | |
237 | tm = rcu_dereference(tm->tcpm_next)) { | |
238 | if (addr_same(&tm->tcpm_addr, &addr)) | |
239 | break; | |
240 | } | |
241 | tcpm_check_stamp(tm, dst); | |
242 | return tm; | |
243 | } | |
244 | ||
81166dd6 DM |
245 | static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock *tw) |
246 | { | |
247 | struct inet6_timewait_sock *tw6; | |
248 | struct tcp_metrics_block *tm; | |
249 | struct inetpeer_addr addr; | |
250 | unsigned int hash; | |
251 | struct net *net; | |
252 | ||
253 | addr.family = tw->tw_family; | |
254 | switch (addr.family) { | |
255 | case AF_INET: | |
256 | addr.addr.a4 = tw->tw_daddr; | |
257 | hash = (__force unsigned int) addr.addr.a4; | |
258 | break; | |
259 | case AF_INET6: | |
260 | tw6 = inet6_twsk((struct sock *)tw); | |
261 | *(struct in6_addr *)addr.addr.a6 = tw6->tw_v6_daddr; | |
ddbe5032 | 262 | hash = ipv6_addr_hash(&tw6->tw_v6_daddr); |
81166dd6 DM |
263 | break; |
264 | default: | |
265 | return NULL; | |
266 | } | |
267 | ||
81166dd6 | 268 | net = twsk_net(tw); |
5815d5e7 | 269 | hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); |
81166dd6 DM |
270 | |
271 | for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; | |
272 | tm = rcu_dereference(tm->tcpm_next)) { | |
273 | if (addr_same(&tm->tcpm_addr, &addr)) | |
274 | break; | |
275 | } | |
276 | return tm; | |
277 | } | |
278 | ||
51c5d0c4 DM |
279 | static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, |
280 | struct dst_entry *dst, | |
281 | bool create) | |
282 | { | |
283 | struct tcp_metrics_block *tm; | |
284 | struct inetpeer_addr addr; | |
285 | unsigned int hash; | |
286 | struct net *net; | |
287 | bool reclaim; | |
288 | ||
289 | addr.family = sk->sk_family; | |
290 | switch (addr.family) { | |
291 | case AF_INET: | |
292 | addr.addr.a4 = inet_sk(sk)->inet_daddr; | |
293 | hash = (__force unsigned int) addr.addr.a4; | |
294 | break; | |
295 | case AF_INET6: | |
296 | *(struct in6_addr *)addr.addr.a6 = inet6_sk(sk)->daddr; | |
ddbe5032 | 297 | hash = ipv6_addr_hash(&inet6_sk(sk)->daddr); |
51c5d0c4 DM |
298 | break; |
299 | default: | |
300 | return NULL; | |
301 | } | |
302 | ||
51c5d0c4 | 303 | net = dev_net(dst->dev); |
5815d5e7 | 304 | hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); |
51c5d0c4 DM |
305 | |
306 | tm = __tcp_get_metrics(&addr, net, hash); | |
307 | reclaim = false; | |
308 | if (tm == TCP_METRICS_RECLAIM_PTR) { | |
309 | reclaim = true; | |
310 | tm = NULL; | |
311 | } | |
312 | if (!tm && create) | |
313 | tm = tcpm_new(dst, &addr, hash, reclaim); | |
314 | else | |
315 | tcpm_check_stamp(tm, dst); | |
316 | ||
317 | return tm; | |
318 | } | |
319 | ||
4aabd8ef DM |
320 | /* Save metrics learned by this TCP session. This function is called |
321 | * only, when TCP finishes successfully i.e. when it enters TIME-WAIT | |
322 | * or goes from LAST-ACK to CLOSE. | |
323 | */ | |
324 | void tcp_update_metrics(struct sock *sk) | |
325 | { | |
51c5d0c4 | 326 | const struct inet_connection_sock *icsk = inet_csk(sk); |
4aabd8ef | 327 | struct dst_entry *dst = __sk_dst_get(sk); |
51c5d0c4 DM |
328 | struct tcp_sock *tp = tcp_sk(sk); |
329 | struct tcp_metrics_block *tm; | |
330 | unsigned long rtt; | |
331 | u32 val; | |
332 | int m; | |
4aabd8ef | 333 | |
51c5d0c4 | 334 | if (sysctl_tcp_nometrics_save || !dst) |
4aabd8ef DM |
335 | return; |
336 | ||
51c5d0c4 | 337 | if (dst->flags & DST_HOST) |
4aabd8ef DM |
338 | dst_confirm(dst); |
339 | ||
51c5d0c4 DM |
340 | rcu_read_lock(); |
341 | if (icsk->icsk_backoff || !tp->srtt) { | |
342 | /* This session failed to estimate rtt. Why? | |
343 | * Probably, no packets returned in time. Reset our | |
344 | * results. | |
345 | */ | |
346 | tm = tcp_get_metrics(sk, dst, false); | |
347 | if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT)) | |
348 | tcp_metric_set(tm, TCP_METRIC_RTT, 0); | |
349 | goto out_unlock; | |
350 | } else | |
351 | tm = tcp_get_metrics(sk, dst, true); | |
4aabd8ef | 352 | |
51c5d0c4 DM |
353 | if (!tm) |
354 | goto out_unlock; | |
4aabd8ef | 355 | |
51c5d0c4 DM |
356 | rtt = tcp_metric_get_jiffies(tm, TCP_METRIC_RTT); |
357 | m = rtt - tp->srtt; | |
4aabd8ef | 358 | |
51c5d0c4 DM |
359 | /* If newly calculated rtt larger than stored one, store new |
360 | * one. Otherwise, use EWMA. Remember, rtt overestimation is | |
361 | * always better than underestimation. | |
362 | */ | |
363 | if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) { | |
364 | if (m <= 0) | |
365 | rtt = tp->srtt; | |
366 | else | |
367 | rtt -= (m >> 3); | |
368 | tcp_metric_set_msecs(tm, TCP_METRIC_RTT, rtt); | |
369 | } | |
4aabd8ef | 370 | |
51c5d0c4 DM |
371 | if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) { |
372 | unsigned long var; | |
4aabd8ef | 373 | |
51c5d0c4 DM |
374 | if (m < 0) |
375 | m = -m; | |
4aabd8ef | 376 | |
51c5d0c4 DM |
377 | /* Scale deviation to rttvar fixed point */ |
378 | m >>= 1; | |
379 | if (m < tp->mdev) | |
380 | m = tp->mdev; | |
4aabd8ef | 381 | |
51c5d0c4 DM |
382 | var = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR); |
383 | if (m >= var) | |
384 | var = m; | |
385 | else | |
386 | var -= (var - m) >> 2; | |
4aabd8ef | 387 | |
51c5d0c4 DM |
388 | tcp_metric_set_msecs(tm, TCP_METRIC_RTTVAR, var); |
389 | } | |
390 | ||
391 | if (tcp_in_initial_slowstart(tp)) { | |
392 | /* Slow start still did not finish. */ | |
393 | if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { | |
394 | val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); | |
395 | if (val && (tp->snd_cwnd >> 1) > val) | |
396 | tcp_metric_set(tm, TCP_METRIC_SSTHRESH, | |
397 | tp->snd_cwnd >> 1); | |
398 | } | |
399 | if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { | |
400 | val = tcp_metric_get(tm, TCP_METRIC_CWND); | |
401 | if (tp->snd_cwnd > val) | |
402 | tcp_metric_set(tm, TCP_METRIC_CWND, | |
403 | tp->snd_cwnd); | |
404 | } | |
405 | } else if (tp->snd_cwnd > tp->snd_ssthresh && | |
406 | icsk->icsk_ca_state == TCP_CA_Open) { | |
407 | /* Cong. avoidance phase, cwnd is reliable. */ | |
408 | if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) | |
409 | tcp_metric_set(tm, TCP_METRIC_SSTHRESH, | |
410 | max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); | |
411 | if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { | |
412 | val = tcp_metric_get(tm, TCP_METRIC_CWND); | |
2100844c | 413 | tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1); |
51c5d0c4 DM |
414 | } |
415 | } else { | |
416 | /* Else slow start did not finish, cwnd is non-sense, | |
417 | * ssthresh may be also invalid. | |
418 | */ | |
419 | if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { | |
420 | val = tcp_metric_get(tm, TCP_METRIC_CWND); | |
421 | tcp_metric_set(tm, TCP_METRIC_CWND, | |
422 | (val + tp->snd_ssthresh) >> 1); | |
423 | } | |
424 | if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { | |
425 | val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); | |
426 | if (val && tp->snd_ssthresh > val) | |
427 | tcp_metric_set(tm, TCP_METRIC_SSTHRESH, | |
428 | tp->snd_ssthresh); | |
429 | } | |
430 | if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) { | |
431 | val = tcp_metric_get(tm, TCP_METRIC_REORDERING); | |
432 | if (val < tp->reordering && | |
4aabd8ef | 433 | tp->reordering != sysctl_tcp_reordering) |
51c5d0c4 DM |
434 | tcp_metric_set(tm, TCP_METRIC_REORDERING, |
435 | tp->reordering); | |
4aabd8ef DM |
436 | } |
437 | } | |
51c5d0c4 DM |
438 | tm->tcpm_stamp = jiffies; |
439 | out_unlock: | |
440 | rcu_read_unlock(); | |
4aabd8ef DM |
441 | } |
442 | ||
443 | /* Initialize metrics on socket. */ | |
444 | ||
445 | void tcp_init_metrics(struct sock *sk) | |
446 | { | |
4aabd8ef | 447 | struct dst_entry *dst = __sk_dst_get(sk); |
51c5d0c4 DM |
448 | struct tcp_sock *tp = tcp_sk(sk); |
449 | struct tcp_metrics_block *tm; | |
450 | u32 val; | |
4aabd8ef DM |
451 | |
452 | if (dst == NULL) | |
453 | goto reset; | |
454 | ||
455 | dst_confirm(dst); | |
456 | ||
51c5d0c4 DM |
457 | rcu_read_lock(); |
458 | tm = tcp_get_metrics(sk, dst, true); | |
459 | if (!tm) { | |
460 | rcu_read_unlock(); | |
461 | goto reset; | |
462 | } | |
463 | ||
464 | if (tcp_metric_locked(tm, TCP_METRIC_CWND)) | |
465 | tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND); | |
466 | ||
467 | val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); | |
468 | if (val) { | |
469 | tp->snd_ssthresh = val; | |
4aabd8ef DM |
470 | if (tp->snd_ssthresh > tp->snd_cwnd_clamp) |
471 | tp->snd_ssthresh = tp->snd_cwnd_clamp; | |
472 | } else { | |
473 | /* ssthresh may have been reduced unnecessarily during. | |
474 | * 3WHS. Restore it back to its initial default. | |
475 | */ | |
476 | tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; | |
477 | } | |
51c5d0c4 DM |
478 | val = tcp_metric_get(tm, TCP_METRIC_REORDERING); |
479 | if (val && tp->reordering != val) { | |
4aabd8ef DM |
480 | tcp_disable_fack(tp); |
481 | tcp_disable_early_retrans(tp); | |
51c5d0c4 | 482 | tp->reordering = val; |
4aabd8ef DM |
483 | } |
484 | ||
51c5d0c4 DM |
485 | val = tcp_metric_get(tm, TCP_METRIC_RTT); |
486 | if (val == 0 || tp->srtt == 0) { | |
487 | rcu_read_unlock(); | |
4aabd8ef | 488 | goto reset; |
51c5d0c4 | 489 | } |
4aabd8ef DM |
490 | /* Initial rtt is determined from SYN,SYN-ACK. |
491 | * The segment is small and rtt may appear much | |
492 | * less than real one. Use per-dst memory | |
493 | * to make it more realistic. | |
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 | */ | |
51c5d0c4 DM |
504 | val = msecs_to_jiffies(val); |
505 | if (val > tp->srtt) { | |
506 | tp->srtt = val; | |
4aabd8ef DM |
507 | tp->rtt_seq = tp->snd_nxt; |
508 | } | |
51c5d0c4 DM |
509 | val = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR); |
510 | if (val > tp->mdev) { | |
511 | tp->mdev = val; | |
4aabd8ef DM |
512 | tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk)); |
513 | } | |
51c5d0c4 DM |
514 | rcu_read_unlock(); |
515 | ||
4aabd8ef DM |
516 | tcp_set_rto(sk); |
517 | reset: | |
518 | if (tp->srtt == 0) { | |
519 | /* RFC6298: 5.7 We've failed to get a valid RTT sample from | |
520 | * 3WHS. This is most likely due to retransmission, | |
521 | * including spurious one. Reset the RTO back to 3secs | |
522 | * from the more aggressive 1sec to avoid more spurious | |
523 | * retransmission. | |
524 | */ | |
525 | tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK; | |
526 | inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; | |
527 | } | |
528 | /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been | |
529 | * retransmitted. In light of RFC6298 more aggressive 1sec | |
530 | * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK | |
531 | * retransmission has occurred. | |
532 | */ | |
533 | if (tp->total_retrans > 1) | |
534 | tp->snd_cwnd = 1; | |
535 | else | |
536 | tp->snd_cwnd = tcp_init_cwnd(tp, dst); | |
537 | tp->snd_cwnd_stamp = tcp_time_stamp; | |
538 | } | |
ab92bb2f | 539 | |
81166dd6 | 540 | bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check) |
ab92bb2f | 541 | { |
51c5d0c4 DM |
542 | struct tcp_metrics_block *tm; |
543 | bool ret; | |
544 | ||
ab92bb2f DM |
545 | if (!dst) |
546 | return false; | |
51c5d0c4 DM |
547 | |
548 | rcu_read_lock(); | |
549 | tm = __tcp_get_metrics_req(req, dst); | |
81166dd6 DM |
550 | if (paws_check) { |
551 | if (tm && | |
552 | (u32)get_seconds() - tm->tcpm_ts_stamp < TCP_PAWS_MSL && | |
553 | (s32)(tm->tcpm_ts - req->ts_recent) > TCP_PAWS_WINDOW) | |
554 | ret = false; | |
555 | else | |
556 | ret = true; | |
557 | } else { | |
558 | if (tm && tcp_metric_get(tm, TCP_METRIC_RTT) && tm->tcpm_ts_stamp) | |
559 | ret = true; | |
560 | else | |
561 | ret = false; | |
562 | } | |
51c5d0c4 DM |
563 | rcu_read_unlock(); |
564 | ||
565 | return ret; | |
ab92bb2f DM |
566 | } |
567 | EXPORT_SYMBOL_GPL(tcp_peer_is_proven); | |
51c5d0c4 | 568 | |
81166dd6 DM |
569 | void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst) |
570 | { | |
571 | struct tcp_metrics_block *tm; | |
572 | ||
573 | rcu_read_lock(); | |
574 | tm = tcp_get_metrics(sk, dst, true); | |
575 | if (tm) { | |
576 | struct tcp_sock *tp = tcp_sk(sk); | |
577 | ||
578 | if ((u32)get_seconds() - tm->tcpm_ts_stamp <= TCP_PAWS_MSL) { | |
579 | tp->rx_opt.ts_recent_stamp = tm->tcpm_ts_stamp; | |
580 | tp->rx_opt.ts_recent = tm->tcpm_ts; | |
581 | } | |
582 | } | |
583 | rcu_read_unlock(); | |
584 | } | |
585 | EXPORT_SYMBOL_GPL(tcp_fetch_timewait_stamp); | |
586 | ||
587 | /* VJ's idea. Save last timestamp seen from this destination and hold | |
588 | * it at least for normal timewait interval to use for duplicate | |
589 | * segment detection in subsequent connections, before they enter | |
590 | * synchronized state. | |
591 | */ | |
592 | bool tcp_remember_stamp(struct sock *sk) | |
593 | { | |
594 | struct dst_entry *dst = __sk_dst_get(sk); | |
595 | bool ret = false; | |
596 | ||
597 | if (dst) { | |
598 | struct tcp_metrics_block *tm; | |
599 | ||
600 | rcu_read_lock(); | |
601 | tm = tcp_get_metrics(sk, dst, true); | |
602 | if (tm) { | |
603 | struct tcp_sock *tp = tcp_sk(sk); | |
604 | ||
605 | if ((s32)(tm->tcpm_ts - tp->rx_opt.ts_recent) <= 0 || | |
606 | ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL && | |
607 | tm->tcpm_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) { | |
608 | tm->tcpm_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp; | |
609 | tm->tcpm_ts = tp->rx_opt.ts_recent; | |
610 | } | |
611 | ret = true; | |
612 | } | |
613 | rcu_read_unlock(); | |
614 | } | |
615 | return ret; | |
616 | } | |
617 | ||
618 | bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw) | |
619 | { | |
620 | struct tcp_metrics_block *tm; | |
621 | bool ret = false; | |
622 | ||
623 | rcu_read_lock(); | |
624 | tm = __tcp_get_metrics_tw(tw); | |
9a0a9502 | 625 | if (tm) { |
81166dd6 DM |
626 | const struct tcp_timewait_sock *tcptw; |
627 | struct sock *sk = (struct sock *) tw; | |
628 | ||
629 | tcptw = tcp_twsk(sk); | |
630 | if ((s32)(tm->tcpm_ts - tcptw->tw_ts_recent) <= 0 || | |
631 | ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL && | |
632 | tm->tcpm_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) { | |
633 | tm->tcpm_ts_stamp = (u32)tcptw->tw_ts_recent_stamp; | |
634 | tm->tcpm_ts = tcptw->tw_ts_recent; | |
635 | } | |
636 | ret = true; | |
637 | } | |
638 | rcu_read_unlock(); | |
639 | ||
640 | return ret; | |
641 | } | |
642 | ||
1fe4c481 YC |
643 | static DEFINE_SEQLOCK(fastopen_seqlock); |
644 | ||
645 | void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, | |
aab48743 YC |
646 | struct tcp_fastopen_cookie *cookie, |
647 | int *syn_loss, unsigned long *last_syn_loss) | |
1fe4c481 YC |
648 | { |
649 | struct tcp_metrics_block *tm; | |
650 | ||
651 | rcu_read_lock(); | |
652 | tm = tcp_get_metrics(sk, __sk_dst_get(sk), false); | |
653 | if (tm) { | |
654 | struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; | |
655 | unsigned int seq; | |
656 | ||
657 | do { | |
658 | seq = read_seqbegin(&fastopen_seqlock); | |
659 | if (tfom->mss) | |
660 | *mss = tfom->mss; | |
661 | *cookie = tfom->cookie; | |
aab48743 YC |
662 | *syn_loss = tfom->syn_loss; |
663 | *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0; | |
1fe4c481 YC |
664 | } while (read_seqretry(&fastopen_seqlock, seq)); |
665 | } | |
666 | rcu_read_unlock(); | |
667 | } | |
668 | ||
1fe4c481 | 669 | void tcp_fastopen_cache_set(struct sock *sk, u16 mss, |
aab48743 | 670 | struct tcp_fastopen_cookie *cookie, bool syn_lost) |
1fe4c481 YC |
671 | { |
672 | struct tcp_metrics_block *tm; | |
673 | ||
674 | rcu_read_lock(); | |
675 | tm = tcp_get_metrics(sk, __sk_dst_get(sk), true); | |
676 | if (tm) { | |
677 | struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; | |
678 | ||
679 | write_seqlock_bh(&fastopen_seqlock); | |
680 | tfom->mss = mss; | |
681 | if (cookie->len > 0) | |
682 | tfom->cookie = *cookie; | |
aab48743 YC |
683 | if (syn_lost) { |
684 | ++tfom->syn_loss; | |
685 | tfom->last_syn_loss = jiffies; | |
686 | } else | |
687 | tfom->syn_loss = 0; | |
1fe4c481 YC |
688 | write_sequnlock_bh(&fastopen_seqlock); |
689 | } | |
690 | rcu_read_unlock(); | |
691 | } | |
692 | ||
5815d5e7 | 693 | static unsigned int tcpmhash_entries; |
51c5d0c4 DM |
694 | static int __init set_tcpmhash_entries(char *str) |
695 | { | |
696 | ssize_t ret; | |
697 | ||
698 | if (!str) | |
699 | return 0; | |
700 | ||
5815d5e7 | 701 | ret = kstrtouint(str, 0, &tcpmhash_entries); |
51c5d0c4 DM |
702 | if (ret) |
703 | return 0; | |
704 | ||
705 | return 1; | |
706 | } | |
707 | __setup("tcpmhash_entries=", set_tcpmhash_entries); | |
708 | ||
709 | static int __net_init tcp_net_metrics_init(struct net *net) | |
710 | { | |
5815d5e7 ED |
711 | size_t size; |
712 | unsigned int slots; | |
51c5d0c4 DM |
713 | |
714 | slots = tcpmhash_entries; | |
715 | if (!slots) { | |
716 | if (totalram_pages >= 128 * 1024) | |
717 | slots = 16 * 1024; | |
718 | else | |
719 | slots = 8 * 1024; | |
720 | } | |
721 | ||
5815d5e7 ED |
722 | net->ipv4.tcp_metrics_hash_log = order_base_2(slots); |
723 | size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log; | |
51c5d0c4 DM |
724 | |
725 | net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL); | |
726 | if (!net->ipv4.tcp_metrics_hash) | |
727 | return -ENOMEM; | |
728 | ||
51c5d0c4 DM |
729 | return 0; |
730 | } | |
731 | ||
732 | static void __net_exit tcp_net_metrics_exit(struct net *net) | |
733 | { | |
36471012 ED |
734 | unsigned int i; |
735 | ||
736 | for (i = 0; i < (1U << net->ipv4.tcp_metrics_hash_log) ; i++) { | |
737 | struct tcp_metrics_block *tm, *next; | |
738 | ||
739 | tm = rcu_dereference_protected(net->ipv4.tcp_metrics_hash[i].chain, 1); | |
740 | while (tm) { | |
741 | next = rcu_dereference_protected(tm->tcpm_next, 1); | |
742 | kfree(tm); | |
743 | tm = next; | |
744 | } | |
745 | } | |
51c5d0c4 DM |
746 | kfree(net->ipv4.tcp_metrics_hash); |
747 | } | |
748 | ||
749 | static __net_initdata struct pernet_operations tcp_net_metrics_ops = { | |
750 | .init = tcp_net_metrics_init, | |
751 | .exit = tcp_net_metrics_exit, | |
752 | }; | |
753 | ||
754 | void __init tcp_metrics_init(void) | |
755 | { | |
756 | register_pernet_subsys(&tcp_net_metrics_ops); | |
757 | } |