blob: 0abe67bb4d3a3adb0d9df820b1fe64b6ef9da591 [file] [log] [blame]
David S. Miller51c5d0c2012-07-10 00:49:14 -07001#include <linux/rcupdate.h>
2#include <linux/spinlock.h>
3#include <linux/jiffies.h>
4#include <linux/bootmem.h>
David S. Millerab92bb22012-07-09 16:19:30 -07005#include <linux/module.h>
David S. Miller4aabd8e2012-07-09 16:07:30 -07006#include <linux/cache.h>
David S. Miller51c5d0c2012-07-10 00:49:14 -07007#include <linux/slab.h>
8#include <linux/init.h>
David S. Miller4aabd8e2012-07-09 16:07:30 -07009#include <linux/tcp.h>
Eric Dumazet5815d5e2012-07-19 23:02:34 +000010#include <linux/hash.h>
David S. Miller4aabd8e2012-07-09 16:07:30 -070011
12#include <net/inet_connection_sock.h>
David S. Miller51c5d0c2012-07-10 00:49:14 -070013#include <net/net_namespace.h>
David S. Millerab92bb22012-07-09 16:19:30 -070014#include <net/request_sock.h>
David S. Miller51c5d0c2012-07-10 00:49:14 -070015#include <net/inetpeer.h>
David S. Miller4aabd8e2012-07-09 16:07:30 -070016#include <net/sock.h>
David S. Miller51c5d0c2012-07-10 00:49:14 -070017#include <net/ipv6.h>
David S. Miller4aabd8e2012-07-09 16:07:30 -070018#include <net/dst.h>
19#include <net/tcp.h>
20
21int sysctl_tcp_nometrics_save __read_mostly;
22
David S. Miller51c5d0c2012-07-10 00:49:14 -070023enum 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
Yuchung Cheng1fe4c482012-07-19 06:43:06 +000034struct tcp_fastopen_metrics {
35 u16 mss;
Yuchung Chengaab48742012-07-19 06:43:10 +000036 u16 syn_loss:10; /* Recurring Fast Open SYN losses */
37 unsigned long last_syn_loss; /* Last Fast Open SYN loss */
Yuchung Cheng1fe4c482012-07-19 06:43:06 +000038 struct tcp_fastopen_cookie cookie;
39};
40
David S. Miller51c5d0c2012-07-10 00:49:14 -070041struct tcp_metrics_block {
42 struct tcp_metrics_block __rcu *tcpm_next;
43 struct inetpeer_addr tcpm_addr;
44 unsigned long tcpm_stamp;
David S. Miller81166dd2012-07-10 03:14:24 -070045 u32 tcpm_ts;
46 u32 tcpm_ts_stamp;
David S. Miller51c5d0c2012-07-10 00:49:14 -070047 u32 tcpm_lock;
48 u32 tcpm_vals[TCP_METRIC_MAX];
Yuchung Cheng1fe4c482012-07-19 06:43:06 +000049 struct tcp_fastopen_metrics tcpm_fastopen;
David S. Miller51c5d0c2012-07-10 00:49:14 -070050};
51
52static 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
58static u32 tcp_metric_get(struct tcp_metrics_block *tm,
59 enum tcp_metric_index idx)
60{
61 return tm->tcpm_vals[idx];
62}
63
64static 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
70static 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
77static 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
84static 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
100struct tcpm_hash_bucket {
101 struct tcp_metrics_block __rcu *chain;
102};
103
104static DEFINE_SPINLOCK(tcp_metrics_lock);
105
106static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst)
107{
108 u32 val;
109
Julian Anastasov9a0a9502012-07-23 10:46:38 +0300110 tm->tcpm_stamp = jiffies;
111
David S. Miller51c5d0c2012-07-10 00:49:14 -0700112 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);
David S. Miller81166dd2012-07-10 03:14:24 -0700130 tm->tcpm_ts = 0;
131 tm->tcpm_ts_stamp = 0;
Yuchung Cheng1fe4c482012-07-19 06:43:06 +0000132 tm->tcpm_fastopen.mss = 0;
Yuchung Chengaab48742012-07-19 06:43:10 +0000133 tm->tcpm_fastopen.syn_loss = 0;
Yuchung Cheng1fe4c482012-07-19 06:43:06 +0000134 tm->tcpm_fastopen.cookie.len = 0;
David S. Miller51c5d0c2012-07-10 00:49:14 -0700135}
136
137static 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;
David S. Miller51c5d0c2012-07-10 00:49:14 -0700163
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
171out_unlock:
172 spin_unlock_bh(&tcp_metrics_lock);
173 return tm;
174}
175
176#define TCP_METRICS_TIMEOUT (60 * 60 * HZ)
177
178static 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
187static 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
196static 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
211static 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;
Eric Dumazetddbe5032012-07-18 08:11:12 +0000227 hash = ipv6_addr_hash(&inet6_rsk(req)->rmt_addr);
David S. Miller51c5d0c2012-07-10 00:49:14 -0700228 break;
229 default:
230 return NULL;
231 }
232
David S. Miller51c5d0c2012-07-10 00:49:14 -0700233 net = dev_net(dst->dev);
Eric Dumazet5815d5e2012-07-19 23:02:34 +0000234 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
David S. Miller51c5d0c2012-07-10 00:49:14 -0700235
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
David S. Miller81166dd2012-07-10 03:14:24 -0700245static 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;
Eric Dumazetddbe5032012-07-18 08:11:12 +0000262 hash = ipv6_addr_hash(&tw6->tw_v6_daddr);
David S. Miller81166dd2012-07-10 03:14:24 -0700263 break;
264 default:
265 return NULL;
266 }
267
David S. Miller81166dd2012-07-10 03:14:24 -0700268 net = twsk_net(tw);
Eric Dumazet5815d5e2012-07-19 23:02:34 +0000269 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
David S. Miller81166dd2012-07-10 03:14:24 -0700270
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
David S. Miller51c5d0c2012-07-10 00:49:14 -0700279static 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;
Eric Dumazetddbe5032012-07-18 08:11:12 +0000297 hash = ipv6_addr_hash(&inet6_sk(sk)->daddr);
David S. Miller51c5d0c2012-07-10 00:49:14 -0700298 break;
299 default:
300 return NULL;
301 }
302
David S. Miller51c5d0c2012-07-10 00:49:14 -0700303 net = dev_net(dst->dev);
Eric Dumazet5815d5e2012-07-19 23:02:34 +0000304 hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);
David S. Miller51c5d0c2012-07-10 00:49:14 -0700305
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
David S. Miller4aabd8e2012-07-09 16:07:30 -0700320/* 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 */
324void tcp_update_metrics(struct sock *sk)
325{
David S. Miller51c5d0c2012-07-10 00:49:14 -0700326 const struct inet_connection_sock *icsk = inet_csk(sk);
David S. Miller4aabd8e2012-07-09 16:07:30 -0700327 struct dst_entry *dst = __sk_dst_get(sk);
David S. Miller51c5d0c2012-07-10 00:49:14 -0700328 struct tcp_sock *tp = tcp_sk(sk);
329 struct tcp_metrics_block *tm;
330 unsigned long rtt;
331 u32 val;
332 int m;
David S. Miller4aabd8e2012-07-09 16:07:30 -0700333
David S. Miller51c5d0c2012-07-10 00:49:14 -0700334 if (sysctl_tcp_nometrics_save || !dst)
David S. Miller4aabd8e2012-07-09 16:07:30 -0700335 return;
336
David S. Miller51c5d0c2012-07-10 00:49:14 -0700337 if (dst->flags & DST_HOST)
David S. Miller4aabd8e2012-07-09 16:07:30 -0700338 dst_confirm(dst);
339
David S. Miller51c5d0c2012-07-10 00:49:14 -0700340 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.
David S. Miller4aabd8e2012-07-09 16:07:30 -0700345 */
David S. Miller51c5d0c2012-07-10 00:49:14 -0700346 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);
352
353 if (!tm)
354 goto out_unlock;
355
356 rtt = tcp_metric_get_jiffies(tm, TCP_METRIC_RTT);
357 m = rtt - tp->srtt;
358
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 }
370
371 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) {
372 unsigned long var;
373
374 if (m < 0)
375 m = -m;
376
377 /* Scale deviation to rttvar fixed point */
378 m >>= 1;
379 if (m < tp->mdev)
380 m = tp->mdev;
381
382 var = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR);
383 if (m >= var)
384 var = m;
385 else
386 var -= (var - m) >> 2;
387
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);
David S. Miller4aabd8e2012-07-09 16:07:30 -0700398 }
David S. Miller51c5d0c2012-07-10 00:49:14 -0700399 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);
David S. Miller4aabd8e2012-07-09 16:07:30 -0700404 }
David S. Miller51c5d0c2012-07-10 00:49:14 -0700405 } 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);
Alexander Duyck21008442012-07-11 17:18:04 -0700413 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1);
David S. Miller4aabd8e2012-07-09 16:07:30 -0700414 }
David S. Miller51c5d0c2012-07-10 00:49:14 -0700415 } 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 &&
David S. Miller4aabd8e2012-07-09 16:07:30 -0700433 tp->reordering != sysctl_tcp_reordering)
David S. Miller51c5d0c2012-07-10 00:49:14 -0700434 tcp_metric_set(tm, TCP_METRIC_REORDERING,
435 tp->reordering);
David S. Miller4aabd8e2012-07-09 16:07:30 -0700436 }
437 }
David S. Miller51c5d0c2012-07-10 00:49:14 -0700438 tm->tcpm_stamp = jiffies;
439out_unlock:
440 rcu_read_unlock();
David S. Miller4aabd8e2012-07-09 16:07:30 -0700441}
442
443/* Initialize metrics on socket. */
444
445void tcp_init_metrics(struct sock *sk)
446{
David S. Miller4aabd8e2012-07-09 16:07:30 -0700447 struct dst_entry *dst = __sk_dst_get(sk);
David S. Miller51c5d0c2012-07-10 00:49:14 -0700448 struct tcp_sock *tp = tcp_sk(sk);
449 struct tcp_metrics_block *tm;
450 u32 val;
David S. Miller4aabd8e2012-07-09 16:07:30 -0700451
452 if (dst == NULL)
453 goto reset;
454
455 dst_confirm(dst);
456
David S. Miller51c5d0c2012-07-10 00:49:14 -0700457 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;
David S. Miller4aabd8e2012-07-09 16:07:30 -0700470 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 }
David S. Miller51c5d0c2012-07-10 00:49:14 -0700478 val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
479 if (val && tp->reordering != val) {
David S. Miller4aabd8e2012-07-09 16:07:30 -0700480 tcp_disable_fack(tp);
481 tcp_disable_early_retrans(tp);
David S. Miller51c5d0c2012-07-10 00:49:14 -0700482 tp->reordering = val;
David S. Miller4aabd8e2012-07-09 16:07:30 -0700483 }
484
David S. Miller51c5d0c2012-07-10 00:49:14 -0700485 val = tcp_metric_get(tm, TCP_METRIC_RTT);
486 if (val == 0 || tp->srtt == 0) {
487 rcu_read_unlock();
David S. Miller4aabd8e2012-07-09 16:07:30 -0700488 goto reset;
David S. Miller51c5d0c2012-07-10 00:49:14 -0700489 }
David S. Miller4aabd8e2012-07-09 16:07:30 -0700490 /* 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 */
David S. Miller51c5d0c2012-07-10 00:49:14 -0700504 val = msecs_to_jiffies(val);
505 if (val > tp->srtt) {
506 tp->srtt = val;
David S. Miller4aabd8e2012-07-09 16:07:30 -0700507 tp->rtt_seq = tp->snd_nxt;
508 }
David S. Miller51c5d0c2012-07-10 00:49:14 -0700509 val = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR);
510 if (val > tp->mdev) {
511 tp->mdev = val;
David S. Miller4aabd8e2012-07-09 16:07:30 -0700512 tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk));
513 }
David S. Miller51c5d0c2012-07-10 00:49:14 -0700514 rcu_read_unlock();
515
David S. Miller4aabd8e2012-07-09 16:07:30 -0700516 tcp_set_rto(sk);
517reset:
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}
David S. Millerab92bb22012-07-09 16:19:30 -0700539
David S. Miller81166dd2012-07-10 03:14:24 -0700540bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check)
David S. Millerab92bb22012-07-09 16:19:30 -0700541{
David S. Miller51c5d0c2012-07-10 00:49:14 -0700542 struct tcp_metrics_block *tm;
543 bool ret;
544
David S. Millerab92bb22012-07-09 16:19:30 -0700545 if (!dst)
546 return false;
David S. Miller51c5d0c2012-07-10 00:49:14 -0700547
548 rcu_read_lock();
549 tm = __tcp_get_metrics_req(req, dst);
David S. Miller81166dd2012-07-10 03:14:24 -0700550 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 }
David S. Miller51c5d0c2012-07-10 00:49:14 -0700563 rcu_read_unlock();
564
565 return ret;
David S. Millerab92bb22012-07-09 16:19:30 -0700566}
567EXPORT_SYMBOL_GPL(tcp_peer_is_proven);
David S. Miller51c5d0c2012-07-10 00:49:14 -0700568
David S. Miller81166dd2012-07-10 03:14:24 -0700569void 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}
585EXPORT_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 */
592bool 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
618bool 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);
Julian Anastasov9a0a9502012-07-23 10:46:38 +0300625 if (tm) {
David S. Miller81166dd2012-07-10 03:14:24 -0700626 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
Yuchung Cheng1fe4c482012-07-19 06:43:06 +0000643static DEFINE_SEQLOCK(fastopen_seqlock);
644
645void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
Yuchung Chengaab48742012-07-19 06:43:10 +0000646 struct tcp_fastopen_cookie *cookie,
647 int *syn_loss, unsigned long *last_syn_loss)
Yuchung Cheng1fe4c482012-07-19 06:43:06 +0000648{
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;
Yuchung Chengaab48742012-07-19 06:43:10 +0000662 *syn_loss = tfom->syn_loss;
663 *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0;
Yuchung Cheng1fe4c482012-07-19 06:43:06 +0000664 } while (read_seqretry(&fastopen_seqlock, seq));
665 }
666 rcu_read_unlock();
667}
668
Yuchung Cheng1fe4c482012-07-19 06:43:06 +0000669void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
Yuchung Chengaab48742012-07-19 06:43:10 +0000670 struct tcp_fastopen_cookie *cookie, bool syn_lost)
Yuchung Cheng1fe4c482012-07-19 06:43:06 +0000671{
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;
Yuchung Chengaab48742012-07-19 06:43:10 +0000683 if (syn_lost) {
684 ++tfom->syn_loss;
685 tfom->last_syn_loss = jiffies;
686 } else
687 tfom->syn_loss = 0;
Yuchung Cheng1fe4c482012-07-19 06:43:06 +0000688 write_sequnlock_bh(&fastopen_seqlock);
689 }
690 rcu_read_unlock();
691}
692
Eric Dumazet5815d5e2012-07-19 23:02:34 +0000693static unsigned int tcpmhash_entries;
David S. Miller51c5d0c2012-07-10 00:49:14 -0700694static int __init set_tcpmhash_entries(char *str)
695{
696 ssize_t ret;
697
698 if (!str)
699 return 0;
700
Eric Dumazet5815d5e2012-07-19 23:02:34 +0000701 ret = kstrtouint(str, 0, &tcpmhash_entries);
David S. Miller51c5d0c2012-07-10 00:49:14 -0700702 if (ret)
703 return 0;
704
705 return 1;
706}
707__setup("tcpmhash_entries=", set_tcpmhash_entries);
708
709static int __net_init tcp_net_metrics_init(struct net *net)
710{
Eric Dumazet5815d5e2012-07-19 23:02:34 +0000711 size_t size;
712 unsigned int slots;
David S. Miller51c5d0c2012-07-10 00:49:14 -0700713
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
Eric Dumazet5815d5e2012-07-19 23:02:34 +0000722 net->ipv4.tcp_metrics_hash_log = order_base_2(slots);
723 size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log;
David S. Miller51c5d0c2012-07-10 00:49:14 -0700724
725 net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL);
726 if (!net->ipv4.tcp_metrics_hash)
727 return -ENOMEM;
728
David S. Miller51c5d0c2012-07-10 00:49:14 -0700729 return 0;
730}
731
732static void __net_exit tcp_net_metrics_exit(struct net *net)
733{
Eric Dumazet36471012012-08-09 11:19:13 +0200734 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 }
David S. Miller51c5d0c2012-07-10 00:49:14 -0700746 kfree(net->ipv4.tcp_metrics_hash);
747}
748
749static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
750 .init = tcp_net_metrics_init,
751 .exit = tcp_net_metrics_exit,
752};
753
754void __init tcp_metrics_init(void)
755{
756 register_pernet_subsys(&tcp_net_metrics_ops);
757}