1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/rcupdate.h>
3 #include <linux/spinlock.h>
4 #include <linux/jiffies.h>
5 #include <linux/module.h>
6 #include <linux/cache.h>
7 #include <linux/slab.h>
8 #include <linux/init.h>
9 #include <linux/tcp.h>
10 #include <linux/hash.h>
11 #include <linux/tcp_metrics.h>
12 #include <linux/vmalloc.h>
13
14 #include <net/inet_connection_sock.h>
15 #include <net/net_namespace.h>
16 #include <net/request_sock.h>
17 #include <net/inetpeer.h>
18 #include <net/sock.h>
19 #include <net/ipv6.h>
20 #include <net/dst.h>
21 #include <net/tcp.h>
22 #include <net/genetlink.h>
23
24 int sysctl_tcp_nometrics_save __read_mostly;
25
26 static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr,
27 const struct inetpeer_addr *daddr,
28 struct net *net, unsigned int hash);
29
30 struct tcp_fastopen_metrics {
31 u16 mss;
32 u16 syn_loss:10, /* Recurring Fast Open SYN losses */
33 try_exp:2; /* Request w/ exp. option (once) */
34 unsigned long last_syn_loss; /* Last Fast Open SYN loss */
35 struct tcp_fastopen_cookie cookie;
36 };
37
38 /* TCP_METRIC_MAX includes 2 extra fields for userspace compatibility
39 * Kernel only stores RTT and RTTVAR in usec resolution
40 */
41 #define TCP_METRIC_MAX_KERNEL (TCP_METRIC_MAX - 2)
42
43 struct tcp_metrics_block {
44 struct tcp_metrics_block __rcu *tcpm_next;
45 possible_net_t tcpm_net;
46 struct inetpeer_addr tcpm_saddr;
47 struct inetpeer_addr tcpm_daddr;
48 unsigned long tcpm_stamp;
49 u32 tcpm_lock;
50 u32 tcpm_vals[TCP_METRIC_MAX_KERNEL + 1];
51 struct tcp_fastopen_metrics tcpm_fastopen;
52
53 struct rcu_head rcu_head;
54 };
55
tm_net(struct tcp_metrics_block * tm)56 static inline struct net *tm_net(struct tcp_metrics_block *tm)
57 {
58 return read_pnet(&tm->tcpm_net);
59 }
60
tcp_metric_locked(struct tcp_metrics_block * tm,enum tcp_metric_index idx)61 static bool tcp_metric_locked(struct tcp_metrics_block *tm,
62 enum tcp_metric_index idx)
63 {
64 return tm->tcpm_lock & (1 << idx);
65 }
66
tcp_metric_get(struct tcp_metrics_block * tm,enum tcp_metric_index idx)67 static u32 tcp_metric_get(struct tcp_metrics_block *tm,
68 enum tcp_metric_index idx)
69 {
70 return tm->tcpm_vals[idx];
71 }
72
tcp_metric_set(struct tcp_metrics_block * tm,enum tcp_metric_index idx,u32 val)73 static void tcp_metric_set(struct tcp_metrics_block *tm,
74 enum tcp_metric_index idx,
75 u32 val)
76 {
77 tm->tcpm_vals[idx] = val;
78 }
79
addr_same(const struct inetpeer_addr * a,const struct inetpeer_addr * b)80 static bool addr_same(const struct inetpeer_addr *a,
81 const struct inetpeer_addr *b)
82 {
83 return inetpeer_addr_cmp(a, b) == 0;
84 }
85
86 struct tcpm_hash_bucket {
87 struct tcp_metrics_block __rcu *chain;
88 };
89
90 static struct tcpm_hash_bucket *tcp_metrics_hash __read_mostly;
91 static unsigned int tcp_metrics_hash_log __read_mostly;
92
93 static DEFINE_SPINLOCK(tcp_metrics_lock);
94
tcpm_suck_dst(struct tcp_metrics_block * tm,const struct dst_entry * dst,bool fastopen_clear)95 static void tcpm_suck_dst(struct tcp_metrics_block *tm,
96 const struct dst_entry *dst,
97 bool fastopen_clear)
98 {
99 u32 msval;
100 u32 val;
101
102 tm->tcpm_stamp = jiffies;
103
104 val = 0;
105 if (dst_metric_locked(dst, RTAX_RTT))
106 val |= 1 << TCP_METRIC_RTT;
107 if (dst_metric_locked(dst, RTAX_RTTVAR))
108 val |= 1 << TCP_METRIC_RTTVAR;
109 if (dst_metric_locked(dst, RTAX_SSTHRESH))
110 val |= 1 << TCP_METRIC_SSTHRESH;
111 if (dst_metric_locked(dst, RTAX_CWND))
112 val |= 1 << TCP_METRIC_CWND;
113 if (dst_metric_locked(dst, RTAX_REORDERING))
114 val |= 1 << TCP_METRIC_REORDERING;
115 tm->tcpm_lock = val;
116
117 msval = dst_metric_raw(dst, RTAX_RTT);
118 tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC;
119
120 msval = dst_metric_raw(dst, RTAX_RTTVAR);
121 tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC;
122 tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH);
123 tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND);
124 tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING);
125 if (fastopen_clear) {
126 tm->tcpm_fastopen.mss = 0;
127 tm->tcpm_fastopen.syn_loss = 0;
128 tm->tcpm_fastopen.try_exp = 0;
129 tm->tcpm_fastopen.cookie.exp = false;
130 tm->tcpm_fastopen.cookie.len = 0;
131 }
132 }
133
134 #define TCP_METRICS_TIMEOUT (60 * 60 * HZ)
135
tcpm_check_stamp(struct tcp_metrics_block * tm,struct dst_entry * dst)136 static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst)
137 {
138 if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT)))
139 tcpm_suck_dst(tm, dst, false);
140 }
141
142 #define TCP_METRICS_RECLAIM_DEPTH 5
143 #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL
144
145 #define deref_locked(p) \
146 rcu_dereference_protected(p, lockdep_is_held(&tcp_metrics_lock))
147
tcpm_new(struct dst_entry * dst,struct inetpeer_addr * saddr,struct inetpeer_addr * daddr,unsigned int hash)148 static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
149 struct inetpeer_addr *saddr,
150 struct inetpeer_addr *daddr,
151 unsigned int hash)
152 {
153 struct tcp_metrics_block *tm;
154 struct net *net;
155 bool reclaim = false;
156
157 spin_lock_bh(&tcp_metrics_lock);
158 net = dev_net(dst->dev);
159
160 /* While waiting for the spin-lock the cache might have been populated
161 * with this entry and so we have to check again.
162 */
163 tm = __tcp_get_metrics(saddr, daddr, net, hash);
164 if (tm == TCP_METRICS_RECLAIM_PTR) {
165 reclaim = true;
166 tm = NULL;
167 }
168 if (tm) {
169 tcpm_check_stamp(tm, dst);
170 goto out_unlock;
171 }
172
173 if (unlikely(reclaim)) {
174 struct tcp_metrics_block *oldest;
175
176 oldest = deref_locked(tcp_metrics_hash[hash].chain);
177 for (tm = deref_locked(oldest->tcpm_next); tm;
178 tm = deref_locked(tm->tcpm_next)) {
179 if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp))
180 oldest = tm;
181 }
182 tm = oldest;
183 } else {
184 tm = kmalloc(sizeof(*tm), GFP_ATOMIC);
185 if (!tm)
186 goto out_unlock;
187 }
188 write_pnet(&tm->tcpm_net, net);
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 = tcp_metrics_hash[hash].chain;
196 rcu_assign_pointer(tcp_metrics_hash[hash].chain, tm);
197 }
198
199 out_unlock:
200 spin_unlock_bh(&tcp_metrics_lock);
201 return tm;
202 }
203
tcp_get_encode(struct tcp_metrics_block * tm,int depth)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
__tcp_get_metrics(const struct inetpeer_addr * saddr,const struct inetpeer_addr * daddr,struct net * net,unsigned int hash)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(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 net_eq(tm_net(tm), net))
225 break;
226 depth++;
227 }
228 return tcp_get_encode(tm, depth);
229 }
230
__tcp_get_metrics_req(struct request_sock * req,struct dst_entry * dst)231 static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
232 struct dst_entry *dst)
233 {
234 struct tcp_metrics_block *tm;
235 struct inetpeer_addr saddr, daddr;
236 unsigned int hash;
237 struct net *net;
238
239 saddr.family = req->rsk_ops->family;
240 daddr.family = req->rsk_ops->family;
241 switch (daddr.family) {
242 case AF_INET:
243 inetpeer_set_addr_v4(&saddr, inet_rsk(req)->ir_loc_addr);
244 inetpeer_set_addr_v4(&daddr, inet_rsk(req)->ir_rmt_addr);
245 hash = ipv4_addr_hash(inet_rsk(req)->ir_rmt_addr);
246 break;
247 #if IS_ENABLED(CONFIG_IPV6)
248 case AF_INET6:
249 inetpeer_set_addr_v6(&saddr, &inet_rsk(req)->ir_v6_loc_addr);
250 inetpeer_set_addr_v6(&daddr, &inet_rsk(req)->ir_v6_rmt_addr);
251 hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr);
252 break;
253 #endif
254 default:
255 return NULL;
256 }
257
258 net = dev_net(dst->dev);
259 hash ^= net_hash_mix(net);
260 hash = hash_32(hash, tcp_metrics_hash_log);
261
262 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
263 tm = rcu_dereference(tm->tcpm_next)) {
264 if (addr_same(&tm->tcpm_saddr, &saddr) &&
265 addr_same(&tm->tcpm_daddr, &daddr) &&
266 net_eq(tm_net(tm), net))
267 break;
268 }
269 tcpm_check_stamp(tm, dst);
270 return tm;
271 }
272
tcp_get_metrics(struct sock * sk,struct dst_entry * dst,bool create)273 static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk,
274 struct dst_entry *dst,
275 bool create)
276 {
277 struct tcp_metrics_block *tm;
278 struct inetpeer_addr saddr, daddr;
279 unsigned int hash;
280 struct net *net;
281
282 if (sk->sk_family == AF_INET) {
283 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr);
284 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr);
285 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr);
286 }
287 #if IS_ENABLED(CONFIG_IPV6)
288 else if (sk->sk_family == AF_INET6) {
289 if (ipv6_addr_v4mapped(&sk->sk_v6_daddr)) {
290 inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr);
291 inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr);
292 hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr);
293 } else {
294 inetpeer_set_addr_v6(&saddr, &sk->sk_v6_rcv_saddr);
295 inetpeer_set_addr_v6(&daddr, &sk->sk_v6_daddr);
296 hash = ipv6_addr_hash(&sk->sk_v6_daddr);
297 }
298 }
299 #endif
300 else
301 return NULL;
302
303 net = dev_net(dst->dev);
304 hash ^= net_hash_mix(net);
305 hash = hash_32(hash, tcp_metrics_hash_log);
306
307 tm = __tcp_get_metrics(&saddr, &daddr, net, hash);
308 if (tm == TCP_METRICS_RECLAIM_PTR)
309 tm = NULL;
310 if (!tm && create)
311 tm = tcpm_new(dst, &saddr, &daddr, hash);
312 else
313 tcpm_check_stamp(tm, dst);
314
315 return tm;
316 }
317
318 /* Save metrics learned by this TCP session. This function is called
319 * only, when TCP finishes successfully i.e. when it enters TIME-WAIT
320 * or goes from LAST-ACK to CLOSE.
321 */
tcp_update_metrics(struct sock * sk)322 void tcp_update_metrics(struct sock *sk)
323 {
324 const struct inet_connection_sock *icsk = inet_csk(sk);
325 struct dst_entry *dst = __sk_dst_get(sk);
326 struct tcp_sock *tp = tcp_sk(sk);
327 struct net *net = sock_net(sk);
328 struct tcp_metrics_block *tm;
329 unsigned long rtt;
330 u32 val;
331 int m;
332
333 sk_dst_confirm(sk);
334 if (sysctl_tcp_nometrics_save || !dst)
335 return;
336
337 rcu_read_lock();
338 if (icsk->icsk_backoff || !tp->srtt_us) {
339 /* This session failed to estimate rtt. Why?
340 * Probably, no packets returned in time. Reset our
341 * results.
342 */
343 tm = tcp_get_metrics(sk, dst, false);
344 if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT))
345 tcp_metric_set(tm, TCP_METRIC_RTT, 0);
346 goto out_unlock;
347 } else
348 tm = tcp_get_metrics(sk, dst, true);
349
350 if (!tm)
351 goto out_unlock;
352
353 rtt = tcp_metric_get(tm, TCP_METRIC_RTT);
354 m = rtt - tp->srtt_us;
355
356 /* If newly calculated rtt larger than stored one, store new
357 * one. Otherwise, use EWMA. Remember, rtt overestimation is
358 * always better than underestimation.
359 */
360 if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) {
361 if (m <= 0)
362 rtt = tp->srtt_us;
363 else
364 rtt -= (m >> 3);
365 tcp_metric_set(tm, TCP_METRIC_RTT, rtt);
366 }
367
368 if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) {
369 unsigned long var;
370
371 if (m < 0)
372 m = -m;
373
374 /* Scale deviation to rttvar fixed point */
375 m >>= 1;
376 if (m < tp->mdev_us)
377 m = tp->mdev_us;
378
379 var = tcp_metric_get(tm, TCP_METRIC_RTTVAR);
380 if (m >= var)
381 var = m;
382 else
383 var -= (var - m) >> 2;
384
385 tcp_metric_set(tm, TCP_METRIC_RTTVAR, var);
386 }
387
388 if (tcp_in_initial_slowstart(tp)) {
389 /* Slow start still did not finish. */
390 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
391 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
392 if (val && (tp->snd_cwnd >> 1) > val)
393 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
394 tp->snd_cwnd >> 1);
395 }
396 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
397 val = tcp_metric_get(tm, TCP_METRIC_CWND);
398 if (tp->snd_cwnd > val)
399 tcp_metric_set(tm, TCP_METRIC_CWND,
400 tp->snd_cwnd);
401 }
402 } else if (!tcp_in_slow_start(tp) &&
403 icsk->icsk_ca_state == TCP_CA_Open) {
404 /* Cong. avoidance phase, cwnd is reliable. */
405 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH))
406 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
407 max(tp->snd_cwnd >> 1, tp->snd_ssthresh));
408 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
409 val = tcp_metric_get(tm, TCP_METRIC_CWND);
410 tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1);
411 }
412 } else {
413 /* Else slow start did not finish, cwnd is non-sense,
414 * ssthresh may be also invalid.
415 */
416 if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) {
417 val = tcp_metric_get(tm, TCP_METRIC_CWND);
418 tcp_metric_set(tm, TCP_METRIC_CWND,
419 (val + tp->snd_ssthresh) >> 1);
420 }
421 if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) {
422 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
423 if (val && tp->snd_ssthresh > val)
424 tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
425 tp->snd_ssthresh);
426 }
427 if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) {
428 val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
429 if (val < tp->reordering &&
430 tp->reordering != net->ipv4.sysctl_tcp_reordering)
431 tcp_metric_set(tm, TCP_METRIC_REORDERING,
432 tp->reordering);
433 }
434 }
435 tm->tcpm_stamp = jiffies;
436 out_unlock:
437 rcu_read_unlock();
438 }
439
440 /* Initialize metrics on socket. */
441
tcp_init_metrics(struct sock * sk)442 void tcp_init_metrics(struct sock *sk)
443 {
444 struct dst_entry *dst = __sk_dst_get(sk);
445 struct tcp_sock *tp = tcp_sk(sk);
446 struct tcp_metrics_block *tm;
447 u32 val, crtt = 0; /* cached RTT scaled by 8 */
448
449 sk_dst_confirm(sk);
450 if (!dst)
451 goto reset;
452
453 rcu_read_lock();
454 tm = tcp_get_metrics(sk, dst, true);
455 if (!tm) {
456 rcu_read_unlock();
457 goto reset;
458 }
459
460 if (tcp_metric_locked(tm, TCP_METRIC_CWND))
461 tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND);
462
463 val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH);
464 if (val) {
465 tp->snd_ssthresh = val;
466 if (tp->snd_ssthresh > tp->snd_cwnd_clamp)
467 tp->snd_ssthresh = tp->snd_cwnd_clamp;
468 } else {
469 /* ssthresh may have been reduced unnecessarily during.
470 * 3WHS. Restore it back to its initial default.
471 */
472 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
473 }
474 val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
475 if (val && tp->reordering != val) {
476 tcp_disable_fack(tp);
477 tp->reordering = val;
478 }
479
480 crtt = tcp_metric_get(tm, TCP_METRIC_RTT);
481 rcu_read_unlock();
482 reset:
483 /* The initial RTT measurement from the SYN/SYN-ACK is not ideal
484 * to seed the RTO for later data packets because SYN packets are
485 * small. Use the per-dst cached values to seed the RTO but keep
486 * the RTT estimator variables intact (e.g., srtt, mdev, rttvar).
487 * Later the RTO will be updated immediately upon obtaining the first
488 * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only
489 * influences the first RTO but not later RTT estimation.
490 *
491 * But if RTT is not available from the SYN (due to retransmits or
492 * syn cookies) or the cache, force a conservative 3secs timeout.
493 *
494 * A bit of theory. RTT is time passed after "normal" sized packet
495 * is sent until it is ACKed. In normal circumstances sending small
496 * packets force peer to delay ACKs and calculation is correct too.
497 * The algorithm is adaptive and, provided we follow specs, it
498 * NEVER underestimate RTT. BUT! If peer tries to make some clever
499 * tricks sort of "quick acks" for time long enough to decrease RTT
500 * to low value, and then abruptly stops to do it and starts to delay
501 * ACKs, wait for troubles.
502 */
503 if (crtt > tp->srtt_us) {
504 /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */
505 crtt /= 8 * USEC_PER_SEC / HZ;
506 inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk));
507 } else if (tp->srtt_us == 0) {
508 /* RFC6298: 5.7 We've failed to get a valid RTT sample from
509 * 3WHS. This is most likely due to retransmission,
510 * including spurious one. Reset the RTO back to 3secs
511 * from the more aggressive 1sec to avoid more spurious
512 * retransmission.
513 */
514 tp->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK);
515 tp->mdev_us = tp->mdev_max_us = tp->rttvar_us;
516
517 inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK;
518 }
519 /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been
520 * retransmitted. In light of RFC6298 more aggressive 1sec
521 * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK
522 * retransmission has occurred.
523 */
524 if (tp->total_retrans > 1)
525 tp->snd_cwnd = 1;
526 else
527 tp->snd_cwnd = tcp_init_cwnd(tp, dst);
528 tp->snd_cwnd_stamp = tcp_jiffies32;
529 }
530
tcp_peer_is_proven(struct request_sock * req,struct dst_entry * dst)531 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst)
532 {
533 struct tcp_metrics_block *tm;
534 bool ret;
535
536 if (!dst)
537 return false;
538
539 rcu_read_lock();
540 tm = __tcp_get_metrics_req(req, dst);
541 if (tm && tcp_metric_get(tm, TCP_METRIC_RTT))
542 ret = true;
543 else
544 ret = false;
545 rcu_read_unlock();
546
547 return ret;
548 }
549
550 static DEFINE_SEQLOCK(fastopen_seqlock);
551
tcp_fastopen_cache_get(struct sock * sk,u16 * mss,struct tcp_fastopen_cookie * cookie,int * syn_loss,unsigned long * last_syn_loss)552 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
553 struct tcp_fastopen_cookie *cookie,
554 int *syn_loss, unsigned long *last_syn_loss)
555 {
556 struct tcp_metrics_block *tm;
557
558 rcu_read_lock();
559 tm = tcp_get_metrics(sk, __sk_dst_get(sk), false);
560 if (tm) {
561 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
562 unsigned int seq;
563
564 do {
565 seq = read_seqbegin(&fastopen_seqlock);
566 if (tfom->mss)
567 *mss = tfom->mss;
568 *cookie = tfom->cookie;
569 if (cookie->len <= 0 && tfom->try_exp == 1)
570 cookie->exp = true;
571 *syn_loss = tfom->syn_loss;
572 *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0;
573 } while (read_seqretry(&fastopen_seqlock, seq));
574 }
575 rcu_read_unlock();
576 }
577
tcp_fastopen_cache_set(struct sock * sk,u16 mss,struct tcp_fastopen_cookie * cookie,bool syn_lost,u16 try_exp)578 void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
579 struct tcp_fastopen_cookie *cookie, bool syn_lost,
580 u16 try_exp)
581 {
582 struct dst_entry *dst = __sk_dst_get(sk);
583 struct tcp_metrics_block *tm;
584
585 if (!dst)
586 return;
587 rcu_read_lock();
588 tm = tcp_get_metrics(sk, dst, true);
589 if (tm) {
590 struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
591
592 write_seqlock_bh(&fastopen_seqlock);
593 if (mss)
594 tfom->mss = mss;
595 if (cookie && cookie->len > 0)
596 tfom->cookie = *cookie;
597 else if (try_exp > tfom->try_exp &&
598 tfom->cookie.len <= 0 && !tfom->cookie.exp)
599 tfom->try_exp = try_exp;
600 if (syn_lost) {
601 ++tfom->syn_loss;
602 tfom->last_syn_loss = jiffies;
603 } else
604 tfom->syn_loss = 0;
605 write_sequnlock_bh(&fastopen_seqlock);
606 }
607 rcu_read_unlock();
608 }
609
610 static struct genl_family tcp_metrics_nl_family;
611
612 static const struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = {
613 [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, },
614 [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY,
615 .len = sizeof(struct in6_addr), },
616 /* Following attributes are not received for GET/DEL,
617 * we keep them for reference
618 */
619 #if 0
620 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, },
621 [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, },
622 [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, },
623 [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, },
624 [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, },
625 [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, },
626 [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, },
627 [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY,
628 .len = TCP_FASTOPEN_COOKIE_MAX, },
629 #endif
630 };
631
632 /* Add attributes, caller cancels its header on failure */
tcp_metrics_fill_info(struct sk_buff * msg,struct tcp_metrics_block * tm)633 static int tcp_metrics_fill_info(struct sk_buff *msg,
634 struct tcp_metrics_block *tm)
635 {
636 struct nlattr *nest;
637 int i;
638
639 switch (tm->tcpm_daddr.family) {
640 case AF_INET:
641 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_ADDR_IPV4,
642 inetpeer_get_addr_v4(&tm->tcpm_daddr)) < 0)
643 goto nla_put_failure;
644 if (nla_put_in_addr(msg, TCP_METRICS_ATTR_SADDR_IPV4,
645 inetpeer_get_addr_v4(&tm->tcpm_saddr)) < 0)
646 goto nla_put_failure;
647 break;
648 case AF_INET6:
649 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_ADDR_IPV6,
650 inetpeer_get_addr_v6(&tm->tcpm_daddr)) < 0)
651 goto nla_put_failure;
652 if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_SADDR_IPV6,
653 inetpeer_get_addr_v6(&tm->tcpm_saddr)) < 0)
654 goto nla_put_failure;
655 break;
656 default:
657 return -EAFNOSUPPORT;
658 }
659
660 if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE,
661 jiffies - tm->tcpm_stamp,
662 TCP_METRICS_ATTR_PAD) < 0)
663 goto nla_put_failure;
664
665 {
666 int n = 0;
667
668 nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS);
669 if (!nest)
670 goto nla_put_failure;
671 for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) {
672 u32 val = tm->tcpm_vals[i];
673
674 if (!val)
675 continue;
676 if (i == TCP_METRIC_RTT) {
677 if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1,
678 val) < 0)
679 goto nla_put_failure;
680 n++;
681 val = max(val / 1000, 1U);
682 }
683 if (i == TCP_METRIC_RTTVAR) {
684 if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1,
685 val) < 0)
686 goto nla_put_failure;
687 n++;
688 val = max(val / 1000, 1U);
689 }
690 if (nla_put_u32(msg, i + 1, val) < 0)
691 goto nla_put_failure;
692 n++;
693 }
694 if (n)
695 nla_nest_end(msg, nest);
696 else
697 nla_nest_cancel(msg, nest);
698 }
699
700 {
701 struct tcp_fastopen_metrics tfom_copy[1], *tfom;
702 unsigned int seq;
703
704 do {
705 seq = read_seqbegin(&fastopen_seqlock);
706 tfom_copy[0] = tm->tcpm_fastopen;
707 } while (read_seqretry(&fastopen_seqlock, seq));
708
709 tfom = tfom_copy;
710 if (tfom->mss &&
711 nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS,
712 tfom->mss) < 0)
713 goto nla_put_failure;
714 if (tfom->syn_loss &&
715 (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS,
716 tfom->syn_loss) < 0 ||
717 nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS,
718 jiffies - tfom->last_syn_loss,
719 TCP_METRICS_ATTR_PAD) < 0))
720 goto nla_put_failure;
721 if (tfom->cookie.len > 0 &&
722 nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE,
723 tfom->cookie.len, tfom->cookie.val) < 0)
724 goto nla_put_failure;
725 }
726
727 return 0;
728
729 nla_put_failure:
730 return -EMSGSIZE;
731 }
732
tcp_metrics_dump_info(struct sk_buff * skb,struct netlink_callback * cb,struct tcp_metrics_block * tm)733 static int tcp_metrics_dump_info(struct sk_buff *skb,
734 struct netlink_callback *cb,
735 struct tcp_metrics_block *tm)
736 {
737 void *hdr;
738
739 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
740 &tcp_metrics_nl_family, NLM_F_MULTI,
741 TCP_METRICS_CMD_GET);
742 if (!hdr)
743 return -EMSGSIZE;
744
745 if (tcp_metrics_fill_info(skb, tm) < 0)
746 goto nla_put_failure;
747
748 genlmsg_end(skb, hdr);
749 return 0;
750
751 nla_put_failure:
752 genlmsg_cancel(skb, hdr);
753 return -EMSGSIZE;
754 }
755
tcp_metrics_nl_dump(struct sk_buff * skb,struct netlink_callback * cb)756 static int tcp_metrics_nl_dump(struct sk_buff *skb,
757 struct netlink_callback *cb)
758 {
759 struct net *net = sock_net(skb->sk);
760 unsigned int max_rows = 1U << tcp_metrics_hash_log;
761 unsigned int row, s_row = cb->args[0];
762 int s_col = cb->args[1], col = s_col;
763
764 for (row = s_row; row < max_rows; row++, s_col = 0) {
765 struct tcp_metrics_block *tm;
766 struct tcpm_hash_bucket *hb = tcp_metrics_hash + row;
767
768 rcu_read_lock();
769 for (col = 0, tm = rcu_dereference(hb->chain); tm;
770 tm = rcu_dereference(tm->tcpm_next), col++) {
771 if (!net_eq(tm_net(tm), net))
772 continue;
773 if (col < s_col)
774 continue;
775 if (tcp_metrics_dump_info(skb, cb, tm) < 0) {
776 rcu_read_unlock();
777 goto done;
778 }
779 }
780 rcu_read_unlock();
781 }
782
783 done:
784 cb->args[0] = row;
785 cb->args[1] = col;
786 return skb->len;
787 }
788
__parse_nl_addr(struct genl_info * info,struct inetpeer_addr * addr,unsigned int * hash,int optional,int v4,int v6)789 static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
790 unsigned int *hash, int optional, int v4, int v6)
791 {
792 struct nlattr *a;
793
794 a = info->attrs[v4];
795 if (a) {
796 inetpeer_set_addr_v4(addr, nla_get_in_addr(a));
797 if (hash)
798 *hash = ipv4_addr_hash(inetpeer_get_addr_v4(addr));
799 return 0;
800 }
801 a = info->attrs[v6];
802 if (a) {
803 struct in6_addr in6;
804
805 if (nla_len(a) != sizeof(struct in6_addr))
806 return -EINVAL;
807 in6 = nla_get_in6_addr(a);
808 inetpeer_set_addr_v6(addr, &in6);
809 if (hash)
810 *hash = ipv6_addr_hash(inetpeer_get_addr_v6(addr));
811 return 0;
812 }
813 return optional ? 1 : -EAFNOSUPPORT;
814 }
815
parse_nl_addr(struct genl_info * info,struct inetpeer_addr * addr,unsigned int * hash,int optional)816 static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr,
817 unsigned int *hash, int optional)
818 {
819 return __parse_nl_addr(info, addr, hash, optional,
820 TCP_METRICS_ATTR_ADDR_IPV4,
821 TCP_METRICS_ATTR_ADDR_IPV6);
822 }
823
parse_nl_saddr(struct genl_info * info,struct inetpeer_addr * addr)824 static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr)
825 {
826 return __parse_nl_addr(info, addr, NULL, 0,
827 TCP_METRICS_ATTR_SADDR_IPV4,
828 TCP_METRICS_ATTR_SADDR_IPV6);
829 }
830
tcp_metrics_nl_cmd_get(struct sk_buff * skb,struct genl_info * info)831 static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
832 {
833 struct tcp_metrics_block *tm;
834 struct inetpeer_addr saddr, daddr;
835 unsigned int hash;
836 struct sk_buff *msg;
837 struct net *net = genl_info_net(info);
838 void *reply;
839 int ret;
840 bool src = true;
841
842 ret = parse_nl_addr(info, &daddr, &hash, 0);
843 if (ret < 0)
844 return ret;
845
846 ret = parse_nl_saddr(info, &saddr);
847 if (ret < 0)
848 src = false;
849
850 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
851 if (!msg)
852 return -ENOMEM;
853
854 reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0,
855 info->genlhdr->cmd);
856 if (!reply)
857 goto nla_put_failure;
858
859 hash ^= net_hash_mix(net);
860 hash = hash_32(hash, tcp_metrics_hash_log);
861 ret = -ESRCH;
862 rcu_read_lock();
863 for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm;
864 tm = rcu_dereference(tm->tcpm_next)) {
865 if (addr_same(&tm->tcpm_daddr, &daddr) &&
866 (!src || addr_same(&tm->tcpm_saddr, &saddr)) &&
867 net_eq(tm_net(tm), net)) {
868 ret = tcp_metrics_fill_info(msg, tm);
869 break;
870 }
871 }
872 rcu_read_unlock();
873 if (ret < 0)
874 goto out_free;
875
876 genlmsg_end(msg, reply);
877 return genlmsg_reply(msg, info);
878
879 nla_put_failure:
880 ret = -EMSGSIZE;
881
882 out_free:
883 nlmsg_free(msg);
884 return ret;
885 }
886
tcp_metrics_flush_all(struct net * net)887 static void tcp_metrics_flush_all(struct net *net)
888 {
889 unsigned int max_rows = 1U << tcp_metrics_hash_log;
890 struct tcpm_hash_bucket *hb = tcp_metrics_hash;
891 struct tcp_metrics_block *tm;
892 unsigned int row;
893
894 for (row = 0; row < max_rows; row++, hb++) {
895 struct tcp_metrics_block __rcu **pp;
896 spin_lock_bh(&tcp_metrics_lock);
897 pp = &hb->chain;
898 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {
899 if (net_eq(tm_net(tm), net)) {
900 *pp = tm->tcpm_next;
901 kfree_rcu(tm, rcu_head);
902 } else {
903 pp = &tm->tcpm_next;
904 }
905 }
906 spin_unlock_bh(&tcp_metrics_lock);
907 }
908 }
909
tcp_metrics_nl_cmd_del(struct sk_buff * skb,struct genl_info * info)910 static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info)
911 {
912 struct tcpm_hash_bucket *hb;
913 struct tcp_metrics_block *tm;
914 struct tcp_metrics_block __rcu **pp;
915 struct inetpeer_addr saddr, daddr;
916 unsigned int hash;
917 struct net *net = genl_info_net(info);
918 int ret;
919 bool src = true, found = false;
920
921 ret = parse_nl_addr(info, &daddr, &hash, 1);
922 if (ret < 0)
923 return ret;
924 if (ret > 0) {
925 tcp_metrics_flush_all(net);
926 return 0;
927 }
928 ret = parse_nl_saddr(info, &saddr);
929 if (ret < 0)
930 src = false;
931
932 hash ^= net_hash_mix(net);
933 hash = hash_32(hash, tcp_metrics_hash_log);
934 hb = tcp_metrics_hash + hash;
935 pp = &hb->chain;
936 spin_lock_bh(&tcp_metrics_lock);
937 for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {
938 if (addr_same(&tm->tcpm_daddr, &daddr) &&
939 (!src || addr_same(&tm->tcpm_saddr, &saddr)) &&
940 net_eq(tm_net(tm), net)) {
941 *pp = tm->tcpm_next;
942 kfree_rcu(tm, rcu_head);
943 found = true;
944 } else {
945 pp = &tm->tcpm_next;
946 }
947 }
948 spin_unlock_bh(&tcp_metrics_lock);
949 if (!found)
950 return -ESRCH;
951 return 0;
952 }
953
954 static const struct genl_ops tcp_metrics_nl_ops[] = {
955 {
956 .cmd = TCP_METRICS_CMD_GET,
957 .doit = tcp_metrics_nl_cmd_get,
958 .dumpit = tcp_metrics_nl_dump,
959 .policy = tcp_metrics_nl_policy,
960 },
961 {
962 .cmd = TCP_METRICS_CMD_DEL,
963 .doit = tcp_metrics_nl_cmd_del,
964 .policy = tcp_metrics_nl_policy,
965 .flags = GENL_ADMIN_PERM,
966 },
967 };
968
969 static struct genl_family tcp_metrics_nl_family __ro_after_init = {
970 .hdrsize = 0,
971 .name = TCP_METRICS_GENL_NAME,
972 .version = TCP_METRICS_GENL_VERSION,
973 .maxattr = TCP_METRICS_ATTR_MAX,
974 .netnsok = true,
975 .module = THIS_MODULE,
976 .ops = tcp_metrics_nl_ops,
977 .n_ops = ARRAY_SIZE(tcp_metrics_nl_ops),
978 };
979
980 static unsigned int tcpmhash_entries;
set_tcpmhash_entries(char * str)981 static int __init set_tcpmhash_entries(char *str)
982 {
983 ssize_t ret;
984
985 if (!str)
986 return 0;
987
988 ret = kstrtouint(str, 0, &tcpmhash_entries);
989 if (ret)
990 return 0;
991
992 return 1;
993 }
994 __setup("tcpmhash_entries=", set_tcpmhash_entries);
995
tcp_net_metrics_init(struct net * net)996 static int __net_init tcp_net_metrics_init(struct net *net)
997 {
998 size_t size;
999 unsigned int slots;
1000
1001 if (!net_eq(net, &init_net))
1002 return 0;
1003
1004 slots = tcpmhash_entries;
1005 if (!slots) {
1006 if (totalram_pages >= 128 * 1024)
1007 slots = 16 * 1024;
1008 else
1009 slots = 8 * 1024;
1010 }
1011
1012 tcp_metrics_hash_log = order_base_2(slots);
1013 size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log;
1014
1015 tcp_metrics_hash = kvzalloc(size, GFP_KERNEL);
1016 if (!tcp_metrics_hash)
1017 return -ENOMEM;
1018
1019 return 0;
1020 }
1021
tcp_net_metrics_exit(struct net * net)1022 static void __net_exit tcp_net_metrics_exit(struct net *net)
1023 {
1024 tcp_metrics_flush_all(net);
1025 }
1026
1027 static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
1028 .init = tcp_net_metrics_init,
1029 .exit = tcp_net_metrics_exit,
1030 };
1031
tcp_metrics_init(void)1032 void __init tcp_metrics_init(void)
1033 {
1034 int ret;
1035
1036 ret = register_pernet_subsys(&tcp_net_metrics_ops);
1037 if (ret < 0)
1038 panic("Could not allocate the tcp_metrics hash table\n");
1039
1040 ret = genl_register_family(&tcp_metrics_nl_family);
1041 if (ret < 0)
1042 panic("Could not register tcp_metrics generic netlink\n");
1043 }
1044