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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Support for INET connection oriented protocols.
8 *
9 * Authors: See the TCP sources
10 */
11
12#include <linux/module.h>
13#include <linux/jhash.h>
14
15#include <net/inet_connection_sock.h>
16#include <net/inet_hashtables.h>
17#include <net/inet_timewait_sock.h>
18#include <net/ip.h>
19#include <net/route.h>
20#include <net/tcp_states.h>
21#include <net/xfrm.h>
22#include <net/tcp.h>
23#include <net/sock_reuseport.h>
24#include <net/addrconf.h>
25
26#if IS_ENABLED(CONFIG_IPV6)
27/* match_sk*_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses
28 * if IPv6 only, and any IPv4 addresses
29 * if not IPv6 only
30 * match_sk*_wildcard == false: addresses must be exactly the same, i.e.
31 * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
32 * and 0.0.0.0 equals to 0.0.0.0 only
33 */
34static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6,
35 const struct in6_addr *sk2_rcv_saddr6,
36 __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
37 bool sk1_ipv6only, bool sk2_ipv6only,
38 bool match_sk1_wildcard,
39 bool match_sk2_wildcard)
40{
41 int addr_type = ipv6_addr_type(sk1_rcv_saddr6);
42 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
43
44 /* if both are mapped, treat as IPv4 */
45 if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
46 if (!sk2_ipv6only) {
47 if (sk1_rcv_saddr == sk2_rcv_saddr)
48 return true;
49 return (match_sk1_wildcard && !sk1_rcv_saddr) ||
50 (match_sk2_wildcard && !sk2_rcv_saddr);
51 }
52 return false;
53 }
54
55 if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
56 return true;
57
58 if (addr_type2 == IPV6_ADDR_ANY && match_sk2_wildcard &&
59 !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
60 return true;
61
62 if (addr_type == IPV6_ADDR_ANY && match_sk1_wildcard &&
63 !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
64 return true;
65
66 if (sk2_rcv_saddr6 &&
67 ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6))
68 return true;
69
70 return false;
71}
72#endif
73
74/* match_sk*_wildcard == true: 0.0.0.0 equals to any IPv4 addresses
75 * match_sk*_wildcard == false: addresses must be exactly the same, i.e.
76 * 0.0.0.0 only equals to 0.0.0.0
77 */
78static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
79 bool sk2_ipv6only, bool match_sk1_wildcard,
80 bool match_sk2_wildcard)
81{
82 if (!sk2_ipv6only) {
83 if (sk1_rcv_saddr == sk2_rcv_saddr)
84 return true;
85 return (match_sk1_wildcard && !sk1_rcv_saddr) ||
86 (match_sk2_wildcard && !sk2_rcv_saddr);
87 }
88 return false;
89}
90
91bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
92 bool match_wildcard)
93{
94#if IS_ENABLED(CONFIG_IPV6)
95 if (sk->sk_family == AF_INET6)
96 return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr,
97 inet6_rcv_saddr(sk2),
98 sk->sk_rcv_saddr,
99 sk2->sk_rcv_saddr,
100 ipv6_only_sock(sk),
101 ipv6_only_sock(sk2),
102 match_wildcard,
103 match_wildcard);
104#endif
105 return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr,
106 ipv6_only_sock(sk2), match_wildcard,
107 match_wildcard);
108}
109EXPORT_SYMBOL(inet_rcv_saddr_equal);
110
111bool inet_rcv_saddr_any(const struct sock *sk)
112{
113#if IS_ENABLED(CONFIG_IPV6)
114 if (sk->sk_family == AF_INET6)
115 return ipv6_addr_any(&sk->sk_v6_rcv_saddr);
116#endif
117 return !sk->sk_rcv_saddr;
118}
119
120void inet_get_local_port_range(struct net *net, int *low, int *high)
121{
122 unsigned int seq;
123
124 do {
125 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
126
127 *low = net->ipv4.ip_local_ports.range[0];
128 *high = net->ipv4.ip_local_ports.range[1];
129 } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
130}
131EXPORT_SYMBOL(inet_get_local_port_range);
132
133static bool inet_use_bhash2_on_bind(const struct sock *sk)
134{
135#if IS_ENABLED(CONFIG_IPV6)
136 if (sk->sk_family == AF_INET6) {
137 int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr);
138
139 return addr_type != IPV6_ADDR_ANY &&
140 addr_type != IPV6_ADDR_MAPPED;
141 }
142#endif
143 return sk->sk_rcv_saddr != htonl(INADDR_ANY);
144}
145
146static bool inet_bind_conflict(const struct sock *sk, struct sock *sk2,
147 kuid_t sk_uid, bool relax,
148 bool reuseport_cb_ok, bool reuseport_ok)
149{
150 int bound_dev_if2;
151
152 if (sk == sk2)
153 return false;
154
155 bound_dev_if2 = READ_ONCE(sk2->sk_bound_dev_if);
156
157 if (!sk->sk_bound_dev_if || !bound_dev_if2 ||
158 sk->sk_bound_dev_if == bound_dev_if2) {
159 if (sk->sk_reuse && sk2->sk_reuse &&
160 sk2->sk_state != TCP_LISTEN) {
161 if (!relax || (!reuseport_ok && sk->sk_reuseport &&
162 sk2->sk_reuseport && reuseport_cb_ok &&
163 (sk2->sk_state == TCP_TIME_WAIT ||
164 uid_eq(sk_uid, sock_i_uid(sk2)))))
165 return true;
166 } else if (!reuseport_ok || !sk->sk_reuseport ||
167 !sk2->sk_reuseport || !reuseport_cb_ok ||
168 (sk2->sk_state != TCP_TIME_WAIT &&
169 !uid_eq(sk_uid, sock_i_uid(sk2)))) {
170 return true;
171 }
172 }
173 return false;
174}
175
176static bool __inet_bhash2_conflict(const struct sock *sk, struct sock *sk2,
177 kuid_t sk_uid, bool relax,
178 bool reuseport_cb_ok, bool reuseport_ok)
179{
180 if (sk->sk_family == AF_INET && ipv6_only_sock(sk2))
181 return false;
182
183 return inet_bind_conflict(sk, sk2, sk_uid, relax,
184 reuseport_cb_ok, reuseport_ok);
185}
186
187static bool inet_bhash2_conflict(const struct sock *sk,
188 const struct inet_bind2_bucket *tb2,
189 kuid_t sk_uid,
190 bool relax, bool reuseport_cb_ok,
191 bool reuseport_ok)
192{
193 struct inet_timewait_sock *tw2;
194 struct sock *sk2;
195
196 sk_for_each_bound_bhash2(sk2, &tb2->owners) {
197 if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax,
198 reuseport_cb_ok, reuseport_ok))
199 return true;
200 }
201
202 twsk_for_each_bound_bhash2(tw2, &tb2->deathrow) {
203 sk2 = (struct sock *)tw2;
204
205 if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax,
206 reuseport_cb_ok, reuseport_ok))
207 return true;
208 }
209
210 return false;
211}
212
213/* This should be called only when the tb and tb2 hashbuckets' locks are held */
214static int inet_csk_bind_conflict(const struct sock *sk,
215 const struct inet_bind_bucket *tb,
216 const struct inet_bind2_bucket *tb2, /* may be null */
217 bool relax, bool reuseport_ok)
218{
219 bool reuseport_cb_ok;
220 struct sock_reuseport *reuseport_cb;
221 kuid_t uid = sock_i_uid((struct sock *)sk);
222
223 rcu_read_lock();
224 reuseport_cb = rcu_dereference(sk->sk_reuseport_cb);
225 /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */
226 reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks);
227 rcu_read_unlock();
228
229 /*
230 * Unlike other sk lookup places we do not check
231 * for sk_net here, since _all_ the socks listed
232 * in tb->owners and tb2->owners list belong
233 * to the same net - the one this bucket belongs to.
234 */
235
236 if (!inet_use_bhash2_on_bind(sk)) {
237 struct sock *sk2;
238
239 sk_for_each_bound(sk2, &tb->owners)
240 if (inet_bind_conflict(sk, sk2, uid, relax,
241 reuseport_cb_ok, reuseport_ok) &&
242 inet_rcv_saddr_equal(sk, sk2, true))
243 return true;
244
245 return false;
246 }
247
248 /* Conflicts with an existing IPV6_ADDR_ANY (if ipv6) or INADDR_ANY (if
249 * ipv4) should have been checked already. We need to do these two
250 * checks separately because their spinlocks have to be acquired/released
251 * independently of each other, to prevent possible deadlocks
252 */
253 return tb2 && inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok,
254 reuseport_ok);
255}
256
257/* Determine if there is a bind conflict with an existing IPV6_ADDR_ANY (if ipv6) or
258 * INADDR_ANY (if ipv4) socket.
259 *
260 * Caller must hold bhash hashbucket lock with local bh disabled, to protect
261 * against concurrent binds on the port for addr any
262 */
263static bool inet_bhash2_addr_any_conflict(const struct sock *sk, int port, int l3mdev,
264 bool relax, bool reuseport_ok)
265{
266 kuid_t uid = sock_i_uid((struct sock *)sk);
267 const struct net *net = sock_net(sk);
268 struct sock_reuseport *reuseport_cb;
269 struct inet_bind_hashbucket *head2;
270 struct inet_bind2_bucket *tb2;
271 bool reuseport_cb_ok;
272
273 rcu_read_lock();
274 reuseport_cb = rcu_dereference(sk->sk_reuseport_cb);
275 /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */
276 reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks);
277 rcu_read_unlock();
278
279 head2 = inet_bhash2_addr_any_hashbucket(sk, net, port);
280
281 spin_lock(&head2->lock);
282
283 inet_bind_bucket_for_each(tb2, &head2->chain)
284 if (inet_bind2_bucket_match_addr_any(tb2, net, port, l3mdev, sk))
285 break;
286
287 if (tb2 && inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok,
288 reuseport_ok)) {
289 spin_unlock(&head2->lock);
290 return true;
291 }
292
293 spin_unlock(&head2->lock);
294 return false;
295}
296
297/*
298 * Find an open port number for the socket. Returns with the
299 * inet_bind_hashbucket locks held if successful.
300 */
301static struct inet_bind_hashbucket *
302inet_csk_find_open_port(const struct sock *sk, struct inet_bind_bucket **tb_ret,
303 struct inet_bind2_bucket **tb2_ret,
304 struct inet_bind_hashbucket **head2_ret, int *port_ret)
305{
306 struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
307 int i, low, high, attempt_half, port, l3mdev;
308 struct inet_bind_hashbucket *head, *head2;
309 struct net *net = sock_net(sk);
310 struct inet_bind2_bucket *tb2;
311 struct inet_bind_bucket *tb;
312 u32 remaining, offset;
313 bool relax = false;
314
315 l3mdev = inet_sk_bound_l3mdev(sk);
316ports_exhausted:
317 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
318other_half_scan:
319 inet_get_local_port_range(net, &low, &high);
320 high++; /* [32768, 60999] -> [32768, 61000[ */
321 if (high - low < 4)
322 attempt_half = 0;
323 if (attempt_half) {
324 int half = low + (((high - low) >> 2) << 1);
325
326 if (attempt_half == 1)
327 high = half;
328 else
329 low = half;
330 }
331 remaining = high - low;
332 if (likely(remaining > 1))
333 remaining &= ~1U;
334
335 offset = get_random_u32_below(remaining);
336 /* __inet_hash_connect() favors ports having @low parity
337 * We do the opposite to not pollute connect() users.
338 */
339 offset |= 1U;
340
341other_parity_scan:
342 port = low + offset;
343 for (i = 0; i < remaining; i += 2, port += 2) {
344 if (unlikely(port >= high))
345 port -= remaining;
346 if (inet_is_local_reserved_port(net, port))
347 continue;
348 head = &hinfo->bhash[inet_bhashfn(net, port,
349 hinfo->bhash_size)];
350 spin_lock_bh(&head->lock);
351 if (inet_use_bhash2_on_bind(sk)) {
352 if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, relax, false))
353 goto next_port;
354 }
355
356 head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
357 spin_lock(&head2->lock);
358 tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk);
359 inet_bind_bucket_for_each(tb, &head->chain)
360 if (inet_bind_bucket_match(tb, net, port, l3mdev)) {
361 if (!inet_csk_bind_conflict(sk, tb, tb2,
362 relax, false))
363 goto success;
364 spin_unlock(&head2->lock);
365 goto next_port;
366 }
367 tb = NULL;
368 goto success;
369next_port:
370 spin_unlock_bh(&head->lock);
371 cond_resched();
372 }
373
374 offset--;
375 if (!(offset & 1))
376 goto other_parity_scan;
377
378 if (attempt_half == 1) {
379 /* OK we now try the upper half of the range */
380 attempt_half = 2;
381 goto other_half_scan;
382 }
383
384 if (READ_ONCE(net->ipv4.sysctl_ip_autobind_reuse) && !relax) {
385 /* We still have a chance to connect to different destinations */
386 relax = true;
387 goto ports_exhausted;
388 }
389 return NULL;
390success:
391 *port_ret = port;
392 *tb_ret = tb;
393 *tb2_ret = tb2;
394 *head2_ret = head2;
395 return head;
396}
397
398static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
399 struct sock *sk)
400{
401 kuid_t uid = sock_i_uid(sk);
402
403 if (tb->fastreuseport <= 0)
404 return 0;
405 if (!sk->sk_reuseport)
406 return 0;
407 if (rcu_access_pointer(sk->sk_reuseport_cb))
408 return 0;
409 if (!uid_eq(tb->fastuid, uid))
410 return 0;
411 /* We only need to check the rcv_saddr if this tb was once marked
412 * without fastreuseport and then was reset, as we can only know that
413 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
414 * owners list.
415 */
416 if (tb->fastreuseport == FASTREUSEPORT_ANY)
417 return 1;
418#if IS_ENABLED(CONFIG_IPV6)
419 if (tb->fast_sk_family == AF_INET6)
420 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
421 inet6_rcv_saddr(sk),
422 tb->fast_rcv_saddr,
423 sk->sk_rcv_saddr,
424 tb->fast_ipv6_only,
425 ipv6_only_sock(sk), true, false);
426#endif
427 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
428 ipv6_only_sock(sk), true, false);
429}
430
431void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
432 struct sock *sk)
433{
434 kuid_t uid = sock_i_uid(sk);
435 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
436
437 if (hlist_empty(&tb->owners)) {
438 tb->fastreuse = reuse;
439 if (sk->sk_reuseport) {
440 tb->fastreuseport = FASTREUSEPORT_ANY;
441 tb->fastuid = uid;
442 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
443 tb->fast_ipv6_only = ipv6_only_sock(sk);
444 tb->fast_sk_family = sk->sk_family;
445#if IS_ENABLED(CONFIG_IPV6)
446 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
447#endif
448 } else {
449 tb->fastreuseport = 0;
450 }
451 } else {
452 if (!reuse)
453 tb->fastreuse = 0;
454 if (sk->sk_reuseport) {
455 /* We didn't match or we don't have fastreuseport set on
456 * the tb, but we have sk_reuseport set on this socket
457 * and we know that there are no bind conflicts with
458 * this socket in this tb, so reset our tb's reuseport
459 * settings so that any subsequent sockets that match
460 * our current socket will be put on the fast path.
461 *
462 * If we reset we need to set FASTREUSEPORT_STRICT so we
463 * do extra checking for all subsequent sk_reuseport
464 * socks.
465 */
466 if (!sk_reuseport_match(tb, sk)) {
467 tb->fastreuseport = FASTREUSEPORT_STRICT;
468 tb->fastuid = uid;
469 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
470 tb->fast_ipv6_only = ipv6_only_sock(sk);
471 tb->fast_sk_family = sk->sk_family;
472#if IS_ENABLED(CONFIG_IPV6)
473 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
474#endif
475 }
476 } else {
477 tb->fastreuseport = 0;
478 }
479 }
480}
481
482/* Obtain a reference to a local port for the given sock,
483 * if snum is zero it means select any available local port.
484 * We try to allocate an odd port (and leave even ports for connect())
485 */
486int inet_csk_get_port(struct sock *sk, unsigned short snum)
487{
488 struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
489 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
490 bool found_port = false, check_bind_conflict = true;
491 bool bhash_created = false, bhash2_created = false;
492 int ret = -EADDRINUSE, port = snum, l3mdev;
493 struct inet_bind_hashbucket *head, *head2;
494 struct inet_bind2_bucket *tb2 = NULL;
495 struct inet_bind_bucket *tb = NULL;
496 bool head2_lock_acquired = false;
497 struct net *net = sock_net(sk);
498
499 l3mdev = inet_sk_bound_l3mdev(sk);
500
501 if (!port) {
502 head = inet_csk_find_open_port(sk, &tb, &tb2, &head2, &port);
503 if (!head)
504 return ret;
505
506 head2_lock_acquired = true;
507
508 if (tb && tb2)
509 goto success;
510 found_port = true;
511 } else {
512 head = &hinfo->bhash[inet_bhashfn(net, port,
513 hinfo->bhash_size)];
514 spin_lock_bh(&head->lock);
515 inet_bind_bucket_for_each(tb, &head->chain)
516 if (inet_bind_bucket_match(tb, net, port, l3mdev))
517 break;
518 }
519
520 if (!tb) {
521 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, net,
522 head, port, l3mdev);
523 if (!tb)
524 goto fail_unlock;
525 bhash_created = true;
526 }
527
528 if (!found_port) {
529 if (!hlist_empty(&tb->owners)) {
530 if (sk->sk_reuse == SK_FORCE_REUSE ||
531 (tb->fastreuse > 0 && reuse) ||
532 sk_reuseport_match(tb, sk))
533 check_bind_conflict = false;
534 }
535
536 if (check_bind_conflict && inet_use_bhash2_on_bind(sk)) {
537 if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, true, true))
538 goto fail_unlock;
539 }
540
541 head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
542 spin_lock(&head2->lock);
543 head2_lock_acquired = true;
544 tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk);
545 }
546
547 if (!tb2) {
548 tb2 = inet_bind2_bucket_create(hinfo->bind2_bucket_cachep,
549 net, head2, port, l3mdev, sk);
550 if (!tb2)
551 goto fail_unlock;
552 bhash2_created = true;
553 }
554
555 if (!found_port && check_bind_conflict) {
556 if (inet_csk_bind_conflict(sk, tb, tb2, true, true))
557 goto fail_unlock;
558 }
559
560success:
561 inet_csk_update_fastreuse(tb, sk);
562
563 if (!inet_csk(sk)->icsk_bind_hash)
564 inet_bind_hash(sk, tb, tb2, port);
565 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
566 WARN_ON(inet_csk(sk)->icsk_bind2_hash != tb2);
567 ret = 0;
568
569fail_unlock:
570 if (ret) {
571 if (bhash_created)
572 inet_bind_bucket_destroy(hinfo->bind_bucket_cachep, tb);
573 if (bhash2_created)
574 inet_bind2_bucket_destroy(hinfo->bind2_bucket_cachep,
575 tb2);
576 }
577 if (head2_lock_acquired)
578 spin_unlock(&head2->lock);
579 spin_unlock_bh(&head->lock);
580 return ret;
581}
582EXPORT_SYMBOL_GPL(inet_csk_get_port);
583
584/*
585 * Wait for an incoming connection, avoid race conditions. This must be called
586 * with the socket locked.
587 */
588static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
589{
590 struct inet_connection_sock *icsk = inet_csk(sk);
591 DEFINE_WAIT(wait);
592 int err;
593
594 /*
595 * True wake-one mechanism for incoming connections: only
596 * one process gets woken up, not the 'whole herd'.
597 * Since we do not 'race & poll' for established sockets
598 * anymore, the common case will execute the loop only once.
599 *
600 * Subtle issue: "add_wait_queue_exclusive()" will be added
601 * after any current non-exclusive waiters, and we know that
602 * it will always _stay_ after any new non-exclusive waiters
603 * because all non-exclusive waiters are added at the
604 * beginning of the wait-queue. As such, it's ok to "drop"
605 * our exclusiveness temporarily when we get woken up without
606 * having to remove and re-insert us on the wait queue.
607 */
608 for (;;) {
609 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
610 TASK_INTERRUPTIBLE);
611 release_sock(sk);
612 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
613 timeo = schedule_timeout(timeo);
614 sched_annotate_sleep();
615 lock_sock(sk);
616 err = 0;
617 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
618 break;
619 err = -EINVAL;
620 if (sk->sk_state != TCP_LISTEN)
621 break;
622 err = sock_intr_errno(timeo);
623 if (signal_pending(current))
624 break;
625 err = -EAGAIN;
626 if (!timeo)
627 break;
628 }
629 finish_wait(sk_sleep(sk), &wait);
630 return err;
631}
632
633/*
634 * This will accept the next outstanding connection.
635 */
636struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
637{
638 struct inet_connection_sock *icsk = inet_csk(sk);
639 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
640 struct request_sock *req;
641 struct sock *newsk;
642 int error;
643
644 lock_sock(sk);
645
646 /* We need to make sure that this socket is listening,
647 * and that it has something pending.
648 */
649 error = -EINVAL;
650 if (sk->sk_state != TCP_LISTEN)
651 goto out_err;
652
653 /* Find already established connection */
654 if (reqsk_queue_empty(queue)) {
655 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
656
657 /* If this is a non blocking socket don't sleep */
658 error = -EAGAIN;
659 if (!timeo)
660 goto out_err;
661
662 error = inet_csk_wait_for_connect(sk, timeo);
663 if (error)
664 goto out_err;
665 }
666 req = reqsk_queue_remove(queue, sk);
667 newsk = req->sk;
668
669 if (sk->sk_protocol == IPPROTO_TCP &&
670 tcp_rsk(req)->tfo_listener) {
671 spin_lock_bh(&queue->fastopenq.lock);
672 if (tcp_rsk(req)->tfo_listener) {
673 /* We are still waiting for the final ACK from 3WHS
674 * so can't free req now. Instead, we set req->sk to
675 * NULL to signify that the child socket is taken
676 * so reqsk_fastopen_remove() will free the req
677 * when 3WHS finishes (or is aborted).
678 */
679 req->sk = NULL;
680 req = NULL;
681 }
682 spin_unlock_bh(&queue->fastopenq.lock);
683 }
684
685out:
686 release_sock(sk);
687 if (newsk && mem_cgroup_sockets_enabled) {
688 int amt;
689
690 /* atomically get the memory usage, set and charge the
691 * newsk->sk_memcg.
692 */
693 lock_sock(newsk);
694
695 /* The socket has not been accepted yet, no need to look at
696 * newsk->sk_wmem_queued.
697 */
698 amt = sk_mem_pages(newsk->sk_forward_alloc +
699 atomic_read(&newsk->sk_rmem_alloc));
700 mem_cgroup_sk_alloc(newsk);
701 if (newsk->sk_memcg && amt)
702 mem_cgroup_charge_skmem(newsk->sk_memcg, amt,
703 GFP_KERNEL | __GFP_NOFAIL);
704
705 release_sock(newsk);
706 }
707 if (req)
708 reqsk_put(req);
709 return newsk;
710out_err:
711 newsk = NULL;
712 req = NULL;
713 *err = error;
714 goto out;
715}
716EXPORT_SYMBOL(inet_csk_accept);
717
718/*
719 * Using different timers for retransmit, delayed acks and probes
720 * We may wish use just one timer maintaining a list of expire jiffies
721 * to optimize.
722 */
723void inet_csk_init_xmit_timers(struct sock *sk,
724 void (*retransmit_handler)(struct timer_list *t),
725 void (*delack_handler)(struct timer_list *t),
726 void (*keepalive_handler)(struct timer_list *t))
727{
728 struct inet_connection_sock *icsk = inet_csk(sk);
729
730 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
731 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
732 timer_setup(&sk->sk_timer, keepalive_handler, 0);
733 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
734}
735EXPORT_SYMBOL(inet_csk_init_xmit_timers);
736
737void inet_csk_clear_xmit_timers(struct sock *sk)
738{
739 struct inet_connection_sock *icsk = inet_csk(sk);
740
741 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
742
743 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
744 sk_stop_timer(sk, &icsk->icsk_delack_timer);
745 sk_stop_timer(sk, &sk->sk_timer);
746}
747EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
748
749void inet_csk_delete_keepalive_timer(struct sock *sk)
750{
751 sk_stop_timer(sk, &sk->sk_timer);
752}
753EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
754
755void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
756{
757 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
758}
759EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
760
761struct dst_entry *inet_csk_route_req(const struct sock *sk,
762 struct flowi4 *fl4,
763 const struct request_sock *req)
764{
765 const struct inet_request_sock *ireq = inet_rsk(req);
766 struct net *net = read_pnet(&ireq->ireq_net);
767 struct ip_options_rcu *opt;
768 struct rtable *rt;
769
770 rcu_read_lock();
771 opt = rcu_dereference(ireq->ireq_opt);
772
773 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
774 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
775 sk->sk_protocol, inet_sk_flowi_flags(sk),
776 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
777 ireq->ir_loc_addr, ireq->ir_rmt_port,
778 htons(ireq->ir_num), sk->sk_uid);
779 security_req_classify_flow(req, flowi4_to_flowi_common(fl4));
780 rt = ip_route_output_flow(net, fl4, sk);
781 if (IS_ERR(rt))
782 goto no_route;
783 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
784 goto route_err;
785 rcu_read_unlock();
786 return &rt->dst;
787
788route_err:
789 ip_rt_put(rt);
790no_route:
791 rcu_read_unlock();
792 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
793 return NULL;
794}
795EXPORT_SYMBOL_GPL(inet_csk_route_req);
796
797struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
798 struct sock *newsk,
799 const struct request_sock *req)
800{
801 const struct inet_request_sock *ireq = inet_rsk(req);
802 struct net *net = read_pnet(&ireq->ireq_net);
803 struct inet_sock *newinet = inet_sk(newsk);
804 struct ip_options_rcu *opt;
805 struct flowi4 *fl4;
806 struct rtable *rt;
807
808 opt = rcu_dereference(ireq->ireq_opt);
809 fl4 = &newinet->cork.fl.u.ip4;
810
811 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
812 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
813 sk->sk_protocol, inet_sk_flowi_flags(sk),
814 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
815 ireq->ir_loc_addr, ireq->ir_rmt_port,
816 htons(ireq->ir_num), sk->sk_uid);
817 security_req_classify_flow(req, flowi4_to_flowi_common(fl4));
818 rt = ip_route_output_flow(net, fl4, sk);
819 if (IS_ERR(rt))
820 goto no_route;
821 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
822 goto route_err;
823 return &rt->dst;
824
825route_err:
826 ip_rt_put(rt);
827no_route:
828 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
829 return NULL;
830}
831EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
832
833/* Decide when to expire the request and when to resend SYN-ACK */
834static void syn_ack_recalc(struct request_sock *req,
835 const int max_syn_ack_retries,
836 const u8 rskq_defer_accept,
837 int *expire, int *resend)
838{
839 if (!rskq_defer_accept) {
840 *expire = req->num_timeout >= max_syn_ack_retries;
841 *resend = 1;
842 return;
843 }
844 *expire = req->num_timeout >= max_syn_ack_retries &&
845 (!inet_rsk(req)->acked || req->num_timeout >= rskq_defer_accept);
846 /* Do not resend while waiting for data after ACK,
847 * start to resend on end of deferring period to give
848 * last chance for data or ACK to create established socket.
849 */
850 *resend = !inet_rsk(req)->acked ||
851 req->num_timeout >= rskq_defer_accept - 1;
852}
853
854int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
855{
856 int err = req->rsk_ops->rtx_syn_ack(parent, req);
857
858 if (!err)
859 req->num_retrans++;
860 return err;
861}
862EXPORT_SYMBOL(inet_rtx_syn_ack);
863
864static struct request_sock *inet_reqsk_clone(struct request_sock *req,
865 struct sock *sk)
866{
867 struct sock *req_sk, *nreq_sk;
868 struct request_sock *nreq;
869
870 nreq = kmem_cache_alloc(req->rsk_ops->slab, GFP_ATOMIC | __GFP_NOWARN);
871 if (!nreq) {
872 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
873
874 /* paired with refcount_inc_not_zero() in reuseport_migrate_sock() */
875 sock_put(sk);
876 return NULL;
877 }
878
879 req_sk = req_to_sk(req);
880 nreq_sk = req_to_sk(nreq);
881
882 memcpy(nreq_sk, req_sk,
883 offsetof(struct sock, sk_dontcopy_begin));
884 memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end,
885 req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end));
886
887 sk_node_init(&nreq_sk->sk_node);
888 nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping;
889#ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
890 nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping;
891#endif
892 nreq_sk->sk_incoming_cpu = req_sk->sk_incoming_cpu;
893
894 nreq->rsk_listener = sk;
895
896 /* We need not acquire fastopenq->lock
897 * because the child socket is locked in inet_csk_listen_stop().
898 */
899 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(nreq)->tfo_listener)
900 rcu_assign_pointer(tcp_sk(nreq->sk)->fastopen_rsk, nreq);
901
902 return nreq;
903}
904
905static void reqsk_queue_migrated(struct request_sock_queue *queue,
906 const struct request_sock *req)
907{
908 if (req->num_timeout == 0)
909 atomic_inc(&queue->young);
910 atomic_inc(&queue->qlen);
911}
912
913static void reqsk_migrate_reset(struct request_sock *req)
914{
915 req->saved_syn = NULL;
916#if IS_ENABLED(CONFIG_IPV6)
917 inet_rsk(req)->ipv6_opt = NULL;
918 inet_rsk(req)->pktopts = NULL;
919#else
920 inet_rsk(req)->ireq_opt = NULL;
921#endif
922}
923
924/* return true if req was found in the ehash table */
925static bool reqsk_queue_unlink(struct request_sock *req)
926{
927 struct sock *sk = req_to_sk(req);
928 bool found = false;
929
930 if (sk_hashed(sk)) {
931 struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk);
932 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
933
934 spin_lock(lock);
935 found = __sk_nulls_del_node_init_rcu(sk);
936 spin_unlock(lock);
937 }
938 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
939 reqsk_put(req);
940 return found;
941}
942
943bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
944{
945 bool unlinked = reqsk_queue_unlink(req);
946
947 if (unlinked) {
948 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
949 reqsk_put(req);
950 }
951 return unlinked;
952}
953EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
954
955void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
956{
957 inet_csk_reqsk_queue_drop(sk, req);
958 reqsk_put(req);
959}
960EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
961
962static void reqsk_timer_handler(struct timer_list *t)
963{
964 struct request_sock *req = from_timer(req, t, rsk_timer);
965 struct request_sock *nreq = NULL, *oreq = req;
966 struct sock *sk_listener = req->rsk_listener;
967 struct inet_connection_sock *icsk;
968 struct request_sock_queue *queue;
969 struct net *net;
970 int max_syn_ack_retries, qlen, expire = 0, resend = 0;
971
972 if (inet_sk_state_load(sk_listener) != TCP_LISTEN) {
973 struct sock *nsk;
974
975 nsk = reuseport_migrate_sock(sk_listener, req_to_sk(req), NULL);
976 if (!nsk)
977 goto drop;
978
979 nreq = inet_reqsk_clone(req, nsk);
980 if (!nreq)
981 goto drop;
982
983 /* The new timer for the cloned req can decrease the 2
984 * by calling inet_csk_reqsk_queue_drop_and_put(), so
985 * hold another count to prevent use-after-free and
986 * call reqsk_put() just before return.
987 */
988 refcount_set(&nreq->rsk_refcnt, 2 + 1);
989 timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
990 reqsk_queue_migrated(&inet_csk(nsk)->icsk_accept_queue, req);
991
992 req = nreq;
993 sk_listener = nsk;
994 }
995
996 icsk = inet_csk(sk_listener);
997 net = sock_net(sk_listener);
998 max_syn_ack_retries = icsk->icsk_syn_retries ? :
999 READ_ONCE(net->ipv4.sysctl_tcp_synack_retries);
1000 /* Normally all the openreqs are young and become mature
1001 * (i.e. converted to established socket) for first timeout.
1002 * If synack was not acknowledged for 1 second, it means
1003 * one of the following things: synack was lost, ack was lost,
1004 * rtt is high or nobody planned to ack (i.e. synflood).
1005 * When server is a bit loaded, queue is populated with old
1006 * open requests, reducing effective size of queue.
1007 * When server is well loaded, queue size reduces to zero
1008 * after several minutes of work. It is not synflood,
1009 * it is normal operation. The solution is pruning
1010 * too old entries overriding normal timeout, when
1011 * situation becomes dangerous.
1012 *
1013 * Essentially, we reserve half of room for young
1014 * embrions; and abort old ones without pity, if old
1015 * ones are about to clog our table.
1016 */
1017 queue = &icsk->icsk_accept_queue;
1018 qlen = reqsk_queue_len(queue);
1019 if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {
1020 int young = reqsk_queue_len_young(queue) << 1;
1021
1022 while (max_syn_ack_retries > 2) {
1023 if (qlen < young)
1024 break;
1025 max_syn_ack_retries--;
1026 young <<= 1;
1027 }
1028 }
1029 syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept),
1030 &expire, &resend);
1031 req->rsk_ops->syn_ack_timeout(req);
1032 if (!expire &&
1033 (!resend ||
1034 !inet_rtx_syn_ack(sk_listener, req) ||
1035 inet_rsk(req)->acked)) {
1036 if (req->num_timeout++ == 0)
1037 atomic_dec(&queue->young);
1038 mod_timer(&req->rsk_timer, jiffies + reqsk_timeout(req, TCP_RTO_MAX));
1039
1040 if (!nreq)
1041 return;
1042
1043 if (!inet_ehash_insert(req_to_sk(nreq), req_to_sk(oreq), NULL)) {
1044 /* delete timer */
1045 inet_csk_reqsk_queue_drop(sk_listener, nreq);
1046 goto no_ownership;
1047 }
1048
1049 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQSUCCESS);
1050 reqsk_migrate_reset(oreq);
1051 reqsk_queue_removed(&inet_csk(oreq->rsk_listener)->icsk_accept_queue, oreq);
1052 reqsk_put(oreq);
1053
1054 reqsk_put(nreq);
1055 return;
1056 }
1057
1058 /* Even if we can clone the req, we may need not retransmit any more
1059 * SYN+ACKs (nreq->num_timeout > max_syn_ack_retries, etc), or another
1060 * CPU may win the "own_req" race so that inet_ehash_insert() fails.
1061 */
1062 if (nreq) {
1063 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQFAILURE);
1064no_ownership:
1065 reqsk_migrate_reset(nreq);
1066 reqsk_queue_removed(queue, nreq);
1067 __reqsk_free(nreq);
1068 }
1069
1070drop:
1071 inet_csk_reqsk_queue_drop_and_put(oreq->rsk_listener, oreq);
1072}
1073
1074static void reqsk_queue_hash_req(struct request_sock *req,
1075 unsigned long timeout)
1076{
1077 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
1078 mod_timer(&req->rsk_timer, jiffies + timeout);
1079
1080 inet_ehash_insert(req_to_sk(req), NULL, NULL);
1081 /* before letting lookups find us, make sure all req fields
1082 * are committed to memory and refcnt initialized.
1083 */
1084 smp_wmb();
1085 refcount_set(&req->rsk_refcnt, 2 + 1);
1086}
1087
1088void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
1089 unsigned long timeout)
1090{
1091 reqsk_queue_hash_req(req, timeout);
1092 inet_csk_reqsk_queue_added(sk);
1093}
1094EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
1095
1096static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk,
1097 const gfp_t priority)
1098{
1099 struct inet_connection_sock *icsk = inet_csk(newsk);
1100
1101 if (!icsk->icsk_ulp_ops)
1102 return;
1103
1104 if (icsk->icsk_ulp_ops->clone)
1105 icsk->icsk_ulp_ops->clone(req, newsk, priority);
1106}
1107
1108/**
1109 * inet_csk_clone_lock - clone an inet socket, and lock its clone
1110 * @sk: the socket to clone
1111 * @req: request_sock
1112 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
1113 *
1114 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
1115 */
1116struct sock *inet_csk_clone_lock(const struct sock *sk,
1117 const struct request_sock *req,
1118 const gfp_t priority)
1119{
1120 struct sock *newsk = sk_clone_lock(sk, priority);
1121
1122 if (newsk) {
1123 struct inet_connection_sock *newicsk = inet_csk(newsk);
1124
1125 inet_sk_set_state(newsk, TCP_SYN_RECV);
1126 newicsk->icsk_bind_hash = NULL;
1127 newicsk->icsk_bind2_hash = NULL;
1128
1129 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
1130 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
1131 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
1132
1133 /* listeners have SOCK_RCU_FREE, not the children */
1134 sock_reset_flag(newsk, SOCK_RCU_FREE);
1135
1136 inet_sk(newsk)->mc_list = NULL;
1137
1138 newsk->sk_mark = inet_rsk(req)->ir_mark;
1139 atomic64_set(&newsk->sk_cookie,
1140 atomic64_read(&inet_rsk(req)->ir_cookie));
1141
1142 newicsk->icsk_retransmits = 0;
1143 newicsk->icsk_backoff = 0;
1144 newicsk->icsk_probes_out = 0;
1145 newicsk->icsk_probes_tstamp = 0;
1146
1147 /* Deinitialize accept_queue to trap illegal accesses. */
1148 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
1149
1150 inet_clone_ulp(req, newsk, priority);
1151
1152 security_inet_csk_clone(newsk, req);
1153 }
1154 return newsk;
1155}
1156EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
1157
1158/*
1159 * At this point, there should be no process reference to this
1160 * socket, and thus no user references at all. Therefore we
1161 * can assume the socket waitqueue is inactive and nobody will
1162 * try to jump onto it.
1163 */
1164void inet_csk_destroy_sock(struct sock *sk)
1165{
1166 WARN_ON(sk->sk_state != TCP_CLOSE);
1167 WARN_ON(!sock_flag(sk, SOCK_DEAD));
1168
1169 /* It cannot be in hash table! */
1170 WARN_ON(!sk_unhashed(sk));
1171
1172 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
1173 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
1174
1175 sk->sk_prot->destroy(sk);
1176
1177 sk_stream_kill_queues(sk);
1178
1179 xfrm_sk_free_policy(sk);
1180
1181 sk_refcnt_debug_release(sk);
1182
1183 this_cpu_dec(*sk->sk_prot->orphan_count);
1184
1185 sock_put(sk);
1186}
1187EXPORT_SYMBOL(inet_csk_destroy_sock);
1188
1189/* This function allows to force a closure of a socket after the call to
1190 * tcp/dccp_create_openreq_child().
1191 */
1192void inet_csk_prepare_forced_close(struct sock *sk)
1193 __releases(&sk->sk_lock.slock)
1194{
1195 /* sk_clone_lock locked the socket and set refcnt to 2 */
1196 bh_unlock_sock(sk);
1197 sock_put(sk);
1198 inet_csk_prepare_for_destroy_sock(sk);
1199 inet_sk(sk)->inet_num = 0;
1200}
1201EXPORT_SYMBOL(inet_csk_prepare_forced_close);
1202
1203static int inet_ulp_can_listen(const struct sock *sk)
1204{
1205 const struct inet_connection_sock *icsk = inet_csk(sk);
1206
1207 if (icsk->icsk_ulp_ops && !icsk->icsk_ulp_ops->clone)
1208 return -EINVAL;
1209
1210 return 0;
1211}
1212
1213int inet_csk_listen_start(struct sock *sk)
1214{
1215 struct inet_connection_sock *icsk = inet_csk(sk);
1216 struct inet_sock *inet = inet_sk(sk);
1217 int err;
1218
1219 err = inet_ulp_can_listen(sk);
1220 if (unlikely(err))
1221 return err;
1222
1223 reqsk_queue_alloc(&icsk->icsk_accept_queue);
1224
1225 sk->sk_ack_backlog = 0;
1226 inet_csk_delack_init(sk);
1227
1228 /* There is race window here: we announce ourselves listening,
1229 * but this transition is still not validated by get_port().
1230 * It is OK, because this socket enters to hash table only
1231 * after validation is complete.
1232 */
1233 inet_sk_state_store(sk, TCP_LISTEN);
1234 err = sk->sk_prot->get_port(sk, inet->inet_num);
1235 if (!err) {
1236 inet->inet_sport = htons(inet->inet_num);
1237
1238 sk_dst_reset(sk);
1239 err = sk->sk_prot->hash(sk);
1240
1241 if (likely(!err))
1242 return 0;
1243 }
1244
1245 inet_sk_set_state(sk, TCP_CLOSE);
1246 return err;
1247}
1248EXPORT_SYMBOL_GPL(inet_csk_listen_start);
1249
1250static void inet_child_forget(struct sock *sk, struct request_sock *req,
1251 struct sock *child)
1252{
1253 sk->sk_prot->disconnect(child, O_NONBLOCK);
1254
1255 sock_orphan(child);
1256
1257 this_cpu_inc(*sk->sk_prot->orphan_count);
1258
1259 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
1260 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req);
1261 BUG_ON(sk != req->rsk_listener);
1262
1263 /* Paranoid, to prevent race condition if
1264 * an inbound pkt destined for child is
1265 * blocked by sock lock in tcp_v4_rcv().
1266 * Also to satisfy an assertion in
1267 * tcp_v4_destroy_sock().
1268 */
1269 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL);
1270 }
1271 inet_csk_destroy_sock(child);
1272}
1273
1274struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
1275 struct request_sock *req,
1276 struct sock *child)
1277{
1278 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
1279
1280 spin_lock(&queue->rskq_lock);
1281 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1282 inet_child_forget(sk, req, child);
1283 child = NULL;
1284 } else {
1285 req->sk = child;
1286 req->dl_next = NULL;
1287 if (queue->rskq_accept_head == NULL)
1288 WRITE_ONCE(queue->rskq_accept_head, req);
1289 else
1290 queue->rskq_accept_tail->dl_next = req;
1291 queue->rskq_accept_tail = req;
1292 sk_acceptq_added(sk);
1293 }
1294 spin_unlock(&queue->rskq_lock);
1295 return child;
1296}
1297EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
1298
1299struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
1300 struct request_sock *req, bool own_req)
1301{
1302 if (own_req) {
1303 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
1304 reqsk_queue_removed(&inet_csk(req->rsk_listener)->icsk_accept_queue, req);
1305
1306 if (sk != req->rsk_listener) {
1307 /* another listening sk has been selected,
1308 * migrate the req to it.
1309 */
1310 struct request_sock *nreq;
1311
1312 /* hold a refcnt for the nreq->rsk_listener
1313 * which is assigned in inet_reqsk_clone()
1314 */
1315 sock_hold(sk);
1316 nreq = inet_reqsk_clone(req, sk);
1317 if (!nreq) {
1318 inet_child_forget(sk, req, child);
1319 goto child_put;
1320 }
1321
1322 refcount_set(&nreq->rsk_refcnt, 1);
1323 if (inet_csk_reqsk_queue_add(sk, nreq, child)) {
1324 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQSUCCESS);
1325 reqsk_migrate_reset(req);
1326 reqsk_put(req);
1327 return child;
1328 }
1329
1330 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
1331 reqsk_migrate_reset(nreq);
1332 __reqsk_free(nreq);
1333 } else if (inet_csk_reqsk_queue_add(sk, req, child)) {
1334 return child;
1335 }
1336 }
1337 /* Too bad, another child took ownership of the request, undo. */
1338child_put:
1339 bh_unlock_sock(child);
1340 sock_put(child);
1341 return NULL;
1342}
1343EXPORT_SYMBOL(inet_csk_complete_hashdance);
1344
1345/*
1346 * This routine closes sockets which have been at least partially
1347 * opened, but not yet accepted.
1348 */
1349void inet_csk_listen_stop(struct sock *sk)
1350{
1351 struct inet_connection_sock *icsk = inet_csk(sk);
1352 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
1353 struct request_sock *next, *req;
1354
1355 /* Following specs, it would be better either to send FIN
1356 * (and enter FIN-WAIT-1, it is normal close)
1357 * or to send active reset (abort).
1358 * Certainly, it is pretty dangerous while synflood, but it is
1359 * bad justification for our negligence 8)
1360 * To be honest, we are not able to make either
1361 * of the variants now. --ANK
1362 */
1363 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
1364 struct sock *child = req->sk, *nsk;
1365 struct request_sock *nreq;
1366
1367 local_bh_disable();
1368 bh_lock_sock(child);
1369 WARN_ON(sock_owned_by_user(child));
1370 sock_hold(child);
1371
1372 nsk = reuseport_migrate_sock(sk, child, NULL);
1373 if (nsk) {
1374 nreq = inet_reqsk_clone(req, nsk);
1375 if (nreq) {
1376 refcount_set(&nreq->rsk_refcnt, 1);
1377
1378 if (inet_csk_reqsk_queue_add(nsk, nreq, child)) {
1379 __NET_INC_STATS(sock_net(nsk),
1380 LINUX_MIB_TCPMIGRATEREQSUCCESS);
1381 reqsk_migrate_reset(req);
1382 } else {
1383 __NET_INC_STATS(sock_net(nsk),
1384 LINUX_MIB_TCPMIGRATEREQFAILURE);
1385 reqsk_migrate_reset(nreq);
1386 __reqsk_free(nreq);
1387 }
1388
1389 /* inet_csk_reqsk_queue_add() has already
1390 * called inet_child_forget() on failure case.
1391 */
1392 goto skip_child_forget;
1393 }
1394 }
1395
1396 inet_child_forget(sk, req, child);
1397skip_child_forget:
1398 reqsk_put(req);
1399 bh_unlock_sock(child);
1400 local_bh_enable();
1401 sock_put(child);
1402
1403 cond_resched();
1404 }
1405 if (queue->fastopenq.rskq_rst_head) {
1406 /* Free all the reqs queued in rskq_rst_head. */
1407 spin_lock_bh(&queue->fastopenq.lock);
1408 req = queue->fastopenq.rskq_rst_head;
1409 queue->fastopenq.rskq_rst_head = NULL;
1410 spin_unlock_bh(&queue->fastopenq.lock);
1411 while (req != NULL) {
1412 next = req->dl_next;
1413 reqsk_put(req);
1414 req = next;
1415 }
1416 }
1417 WARN_ON_ONCE(sk->sk_ack_backlog);
1418}
1419EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1420
1421void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1422{
1423 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1424 const struct inet_sock *inet = inet_sk(sk);
1425
1426 sin->sin_family = AF_INET;
1427 sin->sin_addr.s_addr = inet->inet_daddr;
1428 sin->sin_port = inet->inet_dport;
1429}
1430EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1431
1432static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1433{
1434 const struct inet_sock *inet = inet_sk(sk);
1435 const struct ip_options_rcu *inet_opt;
1436 __be32 daddr = inet->inet_daddr;
1437 struct flowi4 *fl4;
1438 struct rtable *rt;
1439
1440 rcu_read_lock();
1441 inet_opt = rcu_dereference(inet->inet_opt);
1442 if (inet_opt && inet_opt->opt.srr)
1443 daddr = inet_opt->opt.faddr;
1444 fl4 = &fl->u.ip4;
1445 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
1446 inet->inet_saddr, inet->inet_dport,
1447 inet->inet_sport, sk->sk_protocol,
1448 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
1449 if (IS_ERR(rt))
1450 rt = NULL;
1451 if (rt)
1452 sk_setup_caps(sk, &rt->dst);
1453 rcu_read_unlock();
1454
1455 return &rt->dst;
1456}
1457
1458struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1459{
1460 struct dst_entry *dst = __sk_dst_check(sk, 0);
1461 struct inet_sock *inet = inet_sk(sk);
1462
1463 if (!dst) {
1464 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1465 if (!dst)
1466 goto out;
1467 }
1468 dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
1469
1470 dst = __sk_dst_check(sk, 0);
1471 if (!dst)
1472 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1473out:
1474 return dst;
1475}
1476EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);
1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Support for INET connection oriented protocols.
7 *
8 * Authors: See the TCP sources
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or(at your option) any later version.
14 */
15
16#include <linux/module.h>
17#include <linux/jhash.h>
18
19#include <net/inet_connection_sock.h>
20#include <net/inet_hashtables.h>
21#include <net/inet_timewait_sock.h>
22#include <net/ip.h>
23#include <net/route.h>
24#include <net/tcp_states.h>
25#include <net/xfrm.h>
26
27#ifdef INET_CSK_DEBUG
28const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
29EXPORT_SYMBOL(inet_csk_timer_bug_msg);
30#endif
31
32/*
33 * This struct holds the first and last local port number.
34 */
35struct local_ports sysctl_local_ports __read_mostly = {
36 .lock = __SEQLOCK_UNLOCKED(sysctl_local_ports.lock),
37 .range = { 32768, 61000 },
38};
39
40unsigned long *sysctl_local_reserved_ports;
41EXPORT_SYMBOL(sysctl_local_reserved_ports);
42
43void inet_get_local_port_range(int *low, int *high)
44{
45 unsigned int seq;
46
47 do {
48 seq = read_seqbegin(&sysctl_local_ports.lock);
49
50 *low = sysctl_local_ports.range[0];
51 *high = sysctl_local_ports.range[1];
52 } while (read_seqretry(&sysctl_local_ports.lock, seq));
53}
54EXPORT_SYMBOL(inet_get_local_port_range);
55
56int inet_csk_bind_conflict(const struct sock *sk,
57 const struct inet_bind_bucket *tb, bool relax)
58{
59 struct sock *sk2;
60 struct hlist_node *node;
61 int reuse = sk->sk_reuse;
62
63 /*
64 * Unlike other sk lookup places we do not check
65 * for sk_net here, since _all_ the socks listed
66 * in tb->owners list belong to the same net - the
67 * one this bucket belongs to.
68 */
69
70 sk_for_each_bound(sk2, node, &tb->owners) {
71 if (sk != sk2 &&
72 !inet_v6_ipv6only(sk2) &&
73 (!sk->sk_bound_dev_if ||
74 !sk2->sk_bound_dev_if ||
75 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
76 if (!reuse || !sk2->sk_reuse ||
77 sk2->sk_state == TCP_LISTEN) {
78 const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
79 if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||
80 sk2_rcv_saddr == sk_rcv_saddr(sk))
81 break;
82 }
83 if (!relax && reuse && sk2->sk_reuse &&
84 sk2->sk_state != TCP_LISTEN) {
85 const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
86
87 if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||
88 sk2_rcv_saddr == sk_rcv_saddr(sk))
89 break;
90 }
91 }
92 }
93 return node != NULL;
94}
95EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
96
97/* Obtain a reference to a local port for the given sock,
98 * if snum is zero it means select any available local port.
99 */
100int inet_csk_get_port(struct sock *sk, unsigned short snum)
101{
102 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
103 struct inet_bind_hashbucket *head;
104 struct hlist_node *node;
105 struct inet_bind_bucket *tb;
106 int ret, attempts = 5;
107 struct net *net = sock_net(sk);
108 int smallest_size = -1, smallest_rover;
109
110 local_bh_disable();
111 if (!snum) {
112 int remaining, rover, low, high;
113
114again:
115 inet_get_local_port_range(&low, &high);
116 remaining = (high - low) + 1;
117 smallest_rover = rover = net_random() % remaining + low;
118
119 smallest_size = -1;
120 do {
121 if (inet_is_reserved_local_port(rover))
122 goto next_nolock;
123 head = &hashinfo->bhash[inet_bhashfn(net, rover,
124 hashinfo->bhash_size)];
125 spin_lock(&head->lock);
126 inet_bind_bucket_for_each(tb, node, &head->chain)
127 if (net_eq(ib_net(tb), net) && tb->port == rover) {
128 if (tb->fastreuse > 0 &&
129 sk->sk_reuse &&
130 sk->sk_state != TCP_LISTEN &&
131 (tb->num_owners < smallest_size || smallest_size == -1)) {
132 smallest_size = tb->num_owners;
133 smallest_rover = rover;
134 if (atomic_read(&hashinfo->bsockets) > (high - low) + 1 &&
135 !inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
136 snum = smallest_rover;
137 goto tb_found;
138 }
139 }
140 if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
141 snum = rover;
142 goto tb_found;
143 }
144 goto next;
145 }
146 break;
147 next:
148 spin_unlock(&head->lock);
149 next_nolock:
150 if (++rover > high)
151 rover = low;
152 } while (--remaining > 0);
153
154 /* Exhausted local port range during search? It is not
155 * possible for us to be holding one of the bind hash
156 * locks if this test triggers, because if 'remaining'
157 * drops to zero, we broke out of the do/while loop at
158 * the top level, not from the 'break;' statement.
159 */
160 ret = 1;
161 if (remaining <= 0) {
162 if (smallest_size != -1) {
163 snum = smallest_rover;
164 goto have_snum;
165 }
166 goto fail;
167 }
168 /* OK, here is the one we will use. HEAD is
169 * non-NULL and we hold it's mutex.
170 */
171 snum = rover;
172 } else {
173have_snum:
174 head = &hashinfo->bhash[inet_bhashfn(net, snum,
175 hashinfo->bhash_size)];
176 spin_lock(&head->lock);
177 inet_bind_bucket_for_each(tb, node, &head->chain)
178 if (net_eq(ib_net(tb), net) && tb->port == snum)
179 goto tb_found;
180 }
181 tb = NULL;
182 goto tb_not_found;
183tb_found:
184 if (!hlist_empty(&tb->owners)) {
185 if (sk->sk_reuse == SK_FORCE_REUSE)
186 goto success;
187
188 if (tb->fastreuse > 0 &&
189 sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
190 smallest_size == -1) {
191 goto success;
192 } else {
193 ret = 1;
194 if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) {
195 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
196 smallest_size != -1 && --attempts >= 0) {
197 spin_unlock(&head->lock);
198 goto again;
199 }
200
201 goto fail_unlock;
202 }
203 }
204 }
205tb_not_found:
206 ret = 1;
207 if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
208 net, head, snum)) == NULL)
209 goto fail_unlock;
210 if (hlist_empty(&tb->owners)) {
211 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
212 tb->fastreuse = 1;
213 else
214 tb->fastreuse = 0;
215 } else if (tb->fastreuse &&
216 (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
217 tb->fastreuse = 0;
218success:
219 if (!inet_csk(sk)->icsk_bind_hash)
220 inet_bind_hash(sk, tb, snum);
221 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
222 ret = 0;
223
224fail_unlock:
225 spin_unlock(&head->lock);
226fail:
227 local_bh_enable();
228 return ret;
229}
230EXPORT_SYMBOL_GPL(inet_csk_get_port);
231
232/*
233 * Wait for an incoming connection, avoid race conditions. This must be called
234 * with the socket locked.
235 */
236static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
237{
238 struct inet_connection_sock *icsk = inet_csk(sk);
239 DEFINE_WAIT(wait);
240 int err;
241
242 /*
243 * True wake-one mechanism for incoming connections: only
244 * one process gets woken up, not the 'whole herd'.
245 * Since we do not 'race & poll' for established sockets
246 * anymore, the common case will execute the loop only once.
247 *
248 * Subtle issue: "add_wait_queue_exclusive()" will be added
249 * after any current non-exclusive waiters, and we know that
250 * it will always _stay_ after any new non-exclusive waiters
251 * because all non-exclusive waiters are added at the
252 * beginning of the wait-queue. As such, it's ok to "drop"
253 * our exclusiveness temporarily when we get woken up without
254 * having to remove and re-insert us on the wait queue.
255 */
256 for (;;) {
257 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
258 TASK_INTERRUPTIBLE);
259 release_sock(sk);
260 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
261 timeo = schedule_timeout(timeo);
262 lock_sock(sk);
263 err = 0;
264 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
265 break;
266 err = -EINVAL;
267 if (sk->sk_state != TCP_LISTEN)
268 break;
269 err = sock_intr_errno(timeo);
270 if (signal_pending(current))
271 break;
272 err = -EAGAIN;
273 if (!timeo)
274 break;
275 }
276 finish_wait(sk_sleep(sk), &wait);
277 return err;
278}
279
280/*
281 * This will accept the next outstanding connection.
282 */
283struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
284{
285 struct inet_connection_sock *icsk = inet_csk(sk);
286 struct sock *newsk;
287 int error;
288
289 lock_sock(sk);
290
291 /* We need to make sure that this socket is listening,
292 * and that it has something pending.
293 */
294 error = -EINVAL;
295 if (sk->sk_state != TCP_LISTEN)
296 goto out_err;
297
298 /* Find already established connection */
299 if (reqsk_queue_empty(&icsk->icsk_accept_queue)) {
300 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
301
302 /* If this is a non blocking socket don't sleep */
303 error = -EAGAIN;
304 if (!timeo)
305 goto out_err;
306
307 error = inet_csk_wait_for_connect(sk, timeo);
308 if (error)
309 goto out_err;
310 }
311
312 newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
313 WARN_ON(newsk->sk_state == TCP_SYN_RECV);
314out:
315 release_sock(sk);
316 return newsk;
317out_err:
318 newsk = NULL;
319 *err = error;
320 goto out;
321}
322EXPORT_SYMBOL(inet_csk_accept);
323
324/*
325 * Using different timers for retransmit, delayed acks and probes
326 * We may wish use just one timer maintaining a list of expire jiffies
327 * to optimize.
328 */
329void inet_csk_init_xmit_timers(struct sock *sk,
330 void (*retransmit_handler)(unsigned long),
331 void (*delack_handler)(unsigned long),
332 void (*keepalive_handler)(unsigned long))
333{
334 struct inet_connection_sock *icsk = inet_csk(sk);
335
336 setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
337 (unsigned long)sk);
338 setup_timer(&icsk->icsk_delack_timer, delack_handler,
339 (unsigned long)sk);
340 setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
341 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
342}
343EXPORT_SYMBOL(inet_csk_init_xmit_timers);
344
345void inet_csk_clear_xmit_timers(struct sock *sk)
346{
347 struct inet_connection_sock *icsk = inet_csk(sk);
348
349 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
350
351 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
352 sk_stop_timer(sk, &icsk->icsk_delack_timer);
353 sk_stop_timer(sk, &sk->sk_timer);
354}
355EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
356
357void inet_csk_delete_keepalive_timer(struct sock *sk)
358{
359 sk_stop_timer(sk, &sk->sk_timer);
360}
361EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
362
363void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
364{
365 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
366}
367EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
368
369struct dst_entry *inet_csk_route_req(struct sock *sk,
370 struct flowi4 *fl4,
371 const struct request_sock *req)
372{
373 struct rtable *rt;
374 const struct inet_request_sock *ireq = inet_rsk(req);
375 struct ip_options_rcu *opt = inet_rsk(req)->opt;
376 struct net *net = sock_net(sk);
377
378 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
379 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
380 sk->sk_protocol,
381 inet_sk_flowi_flags(sk) & ~FLOWI_FLAG_PRECOW_METRICS,
382 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr,
383 ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport);
384 security_req_classify_flow(req, flowi4_to_flowi(fl4));
385 rt = ip_route_output_flow(net, fl4, sk);
386 if (IS_ERR(rt))
387 goto no_route;
388 if (opt && opt->opt.is_strictroute && fl4->daddr != rt->rt_gateway)
389 goto route_err;
390 return &rt->dst;
391
392route_err:
393 ip_rt_put(rt);
394no_route:
395 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
396 return NULL;
397}
398EXPORT_SYMBOL_GPL(inet_csk_route_req);
399
400struct dst_entry *inet_csk_route_child_sock(struct sock *sk,
401 struct sock *newsk,
402 const struct request_sock *req)
403{
404 const struct inet_request_sock *ireq = inet_rsk(req);
405 struct inet_sock *newinet = inet_sk(newsk);
406 struct ip_options_rcu *opt = ireq->opt;
407 struct net *net = sock_net(sk);
408 struct flowi4 *fl4;
409 struct rtable *rt;
410
411 fl4 = &newinet->cork.fl.u.ip4;
412 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
413 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
414 sk->sk_protocol, inet_sk_flowi_flags(sk),
415 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr,
416 ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport);
417 security_req_classify_flow(req, flowi4_to_flowi(fl4));
418 rt = ip_route_output_flow(net, fl4, sk);
419 if (IS_ERR(rt))
420 goto no_route;
421 if (opt && opt->opt.is_strictroute && fl4->daddr != rt->rt_gateway)
422 goto route_err;
423 return &rt->dst;
424
425route_err:
426 ip_rt_put(rt);
427no_route:
428 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
429 return NULL;
430}
431EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
432
433static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
434 const u32 rnd, const u32 synq_hsize)
435{
436 return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
437}
438
439#if IS_ENABLED(CONFIG_IPV6)
440#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
441#else
442#define AF_INET_FAMILY(fam) 1
443#endif
444
445struct request_sock *inet_csk_search_req(const struct sock *sk,
446 struct request_sock ***prevp,
447 const __be16 rport, const __be32 raddr,
448 const __be32 laddr)
449{
450 const struct inet_connection_sock *icsk = inet_csk(sk);
451 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
452 struct request_sock *req, **prev;
453
454 for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd,
455 lopt->nr_table_entries)];
456 (req = *prev) != NULL;
457 prev = &req->dl_next) {
458 const struct inet_request_sock *ireq = inet_rsk(req);
459
460 if (ireq->rmt_port == rport &&
461 ireq->rmt_addr == raddr &&
462 ireq->loc_addr == laddr &&
463 AF_INET_FAMILY(req->rsk_ops->family)) {
464 WARN_ON(req->sk);
465 *prevp = prev;
466 break;
467 }
468 }
469
470 return req;
471}
472EXPORT_SYMBOL_GPL(inet_csk_search_req);
473
474void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
475 unsigned long timeout)
476{
477 struct inet_connection_sock *icsk = inet_csk(sk);
478 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
479 const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port,
480 lopt->hash_rnd, lopt->nr_table_entries);
481
482 reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
483 inet_csk_reqsk_queue_added(sk, timeout);
484}
485EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
486
487/* Only thing we need from tcp.h */
488extern int sysctl_tcp_synack_retries;
489
490
491/* Decide when to expire the request and when to resend SYN-ACK */
492static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
493 const int max_retries,
494 const u8 rskq_defer_accept,
495 int *expire, int *resend)
496{
497 if (!rskq_defer_accept) {
498 *expire = req->retrans >= thresh;
499 *resend = 1;
500 return;
501 }
502 *expire = req->retrans >= thresh &&
503 (!inet_rsk(req)->acked || req->retrans >= max_retries);
504 /*
505 * Do not resend while waiting for data after ACK,
506 * start to resend on end of deferring period to give
507 * last chance for data or ACK to create established socket.
508 */
509 *resend = !inet_rsk(req)->acked ||
510 req->retrans >= rskq_defer_accept - 1;
511}
512
513void inet_csk_reqsk_queue_prune(struct sock *parent,
514 const unsigned long interval,
515 const unsigned long timeout,
516 const unsigned long max_rto)
517{
518 struct inet_connection_sock *icsk = inet_csk(parent);
519 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
520 struct listen_sock *lopt = queue->listen_opt;
521 int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
522 int thresh = max_retries;
523 unsigned long now = jiffies;
524 struct request_sock **reqp, *req;
525 int i, budget;
526
527 if (lopt == NULL || lopt->qlen == 0)
528 return;
529
530 /* Normally all the openreqs are young and become mature
531 * (i.e. converted to established socket) for first timeout.
532 * If synack was not acknowledged for 1 second, it means
533 * one of the following things: synack was lost, ack was lost,
534 * rtt is high or nobody planned to ack (i.e. synflood).
535 * When server is a bit loaded, queue is populated with old
536 * open requests, reducing effective size of queue.
537 * When server is well loaded, queue size reduces to zero
538 * after several minutes of work. It is not synflood,
539 * it is normal operation. The solution is pruning
540 * too old entries overriding normal timeout, when
541 * situation becomes dangerous.
542 *
543 * Essentially, we reserve half of room for young
544 * embrions; and abort old ones without pity, if old
545 * ones are about to clog our table.
546 */
547 if (lopt->qlen>>(lopt->max_qlen_log-1)) {
548 int young = (lopt->qlen_young<<1);
549
550 while (thresh > 2) {
551 if (lopt->qlen < young)
552 break;
553 thresh--;
554 young <<= 1;
555 }
556 }
557
558 if (queue->rskq_defer_accept)
559 max_retries = queue->rskq_defer_accept;
560
561 budget = 2 * (lopt->nr_table_entries / (timeout / interval));
562 i = lopt->clock_hand;
563
564 do {
565 reqp=&lopt->syn_table[i];
566 while ((req = *reqp) != NULL) {
567 if (time_after_eq(now, req->expires)) {
568 int expire = 0, resend = 0;
569
570 syn_ack_recalc(req, thresh, max_retries,
571 queue->rskq_defer_accept,
572 &expire, &resend);
573 req->rsk_ops->syn_ack_timeout(parent, req);
574 if (!expire &&
575 (!resend ||
576 !req->rsk_ops->rtx_syn_ack(parent, req, NULL) ||
577 inet_rsk(req)->acked)) {
578 unsigned long timeo;
579
580 if (req->retrans++ == 0)
581 lopt->qlen_young--;
582 timeo = min((timeout << req->retrans), max_rto);
583 req->expires = now + timeo;
584 reqp = &req->dl_next;
585 continue;
586 }
587
588 /* Drop this request */
589 inet_csk_reqsk_queue_unlink(parent, req, reqp);
590 reqsk_queue_removed(queue, req);
591 reqsk_free(req);
592 continue;
593 }
594 reqp = &req->dl_next;
595 }
596
597 i = (i + 1) & (lopt->nr_table_entries - 1);
598
599 } while (--budget > 0);
600
601 lopt->clock_hand = i;
602
603 if (lopt->qlen)
604 inet_csk_reset_keepalive_timer(parent, interval);
605}
606EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
607
608/**
609 * inet_csk_clone_lock - clone an inet socket, and lock its clone
610 * @sk: the socket to clone
611 * @req: request_sock
612 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
613 *
614 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
615 */
616struct sock *inet_csk_clone_lock(const struct sock *sk,
617 const struct request_sock *req,
618 const gfp_t priority)
619{
620 struct sock *newsk = sk_clone_lock(sk, priority);
621
622 if (newsk != NULL) {
623 struct inet_connection_sock *newicsk = inet_csk(newsk);
624
625 newsk->sk_state = TCP_SYN_RECV;
626 newicsk->icsk_bind_hash = NULL;
627
628 inet_sk(newsk)->inet_dport = inet_rsk(req)->rmt_port;
629 inet_sk(newsk)->inet_num = ntohs(inet_rsk(req)->loc_port);
630 inet_sk(newsk)->inet_sport = inet_rsk(req)->loc_port;
631 newsk->sk_write_space = sk_stream_write_space;
632
633 newicsk->icsk_retransmits = 0;
634 newicsk->icsk_backoff = 0;
635 newicsk->icsk_probes_out = 0;
636
637 /* Deinitialize accept_queue to trap illegal accesses. */
638 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
639
640 security_inet_csk_clone(newsk, req);
641 }
642 return newsk;
643}
644EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
645
646/*
647 * At this point, there should be no process reference to this
648 * socket, and thus no user references at all. Therefore we
649 * can assume the socket waitqueue is inactive and nobody will
650 * try to jump onto it.
651 */
652void inet_csk_destroy_sock(struct sock *sk)
653{
654 WARN_ON(sk->sk_state != TCP_CLOSE);
655 WARN_ON(!sock_flag(sk, SOCK_DEAD));
656
657 /* It cannot be in hash table! */
658 WARN_ON(!sk_unhashed(sk));
659
660 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
661 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
662
663 sk->sk_prot->destroy(sk);
664
665 sk_stream_kill_queues(sk);
666
667 xfrm_sk_free_policy(sk);
668
669 sk_refcnt_debug_release(sk);
670
671 percpu_counter_dec(sk->sk_prot->orphan_count);
672 sock_put(sk);
673}
674EXPORT_SYMBOL(inet_csk_destroy_sock);
675
676int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
677{
678 struct inet_sock *inet = inet_sk(sk);
679 struct inet_connection_sock *icsk = inet_csk(sk);
680 int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
681
682 if (rc != 0)
683 return rc;
684
685 sk->sk_max_ack_backlog = 0;
686 sk->sk_ack_backlog = 0;
687 inet_csk_delack_init(sk);
688
689 /* There is race window here: we announce ourselves listening,
690 * but this transition is still not validated by get_port().
691 * It is OK, because this socket enters to hash table only
692 * after validation is complete.
693 */
694 sk->sk_state = TCP_LISTEN;
695 if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
696 inet->inet_sport = htons(inet->inet_num);
697
698 sk_dst_reset(sk);
699 sk->sk_prot->hash(sk);
700
701 return 0;
702 }
703
704 sk->sk_state = TCP_CLOSE;
705 __reqsk_queue_destroy(&icsk->icsk_accept_queue);
706 return -EADDRINUSE;
707}
708EXPORT_SYMBOL_GPL(inet_csk_listen_start);
709
710/*
711 * This routine closes sockets which have been at least partially
712 * opened, but not yet accepted.
713 */
714void inet_csk_listen_stop(struct sock *sk)
715{
716 struct inet_connection_sock *icsk = inet_csk(sk);
717 struct request_sock *acc_req;
718 struct request_sock *req;
719
720 inet_csk_delete_keepalive_timer(sk);
721
722 /* make all the listen_opt local to us */
723 acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue);
724
725 /* Following specs, it would be better either to send FIN
726 * (and enter FIN-WAIT-1, it is normal close)
727 * or to send active reset (abort).
728 * Certainly, it is pretty dangerous while synflood, but it is
729 * bad justification for our negligence 8)
730 * To be honest, we are not able to make either
731 * of the variants now. --ANK
732 */
733 reqsk_queue_destroy(&icsk->icsk_accept_queue);
734
735 while ((req = acc_req) != NULL) {
736 struct sock *child = req->sk;
737
738 acc_req = req->dl_next;
739
740 local_bh_disable();
741 bh_lock_sock(child);
742 WARN_ON(sock_owned_by_user(child));
743 sock_hold(child);
744
745 sk->sk_prot->disconnect(child, O_NONBLOCK);
746
747 sock_orphan(child);
748
749 percpu_counter_inc(sk->sk_prot->orphan_count);
750
751 inet_csk_destroy_sock(child);
752
753 bh_unlock_sock(child);
754 local_bh_enable();
755 sock_put(child);
756
757 sk_acceptq_removed(sk);
758 __reqsk_free(req);
759 }
760 WARN_ON(sk->sk_ack_backlog);
761}
762EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
763
764void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
765{
766 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
767 const struct inet_sock *inet = inet_sk(sk);
768
769 sin->sin_family = AF_INET;
770 sin->sin_addr.s_addr = inet->inet_daddr;
771 sin->sin_port = inet->inet_dport;
772}
773EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
774
775#ifdef CONFIG_COMPAT
776int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
777 char __user *optval, int __user *optlen)
778{
779 const struct inet_connection_sock *icsk = inet_csk(sk);
780
781 if (icsk->icsk_af_ops->compat_getsockopt != NULL)
782 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
783 optval, optlen);
784 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
785 optval, optlen);
786}
787EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
788
789int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
790 char __user *optval, unsigned int optlen)
791{
792 const struct inet_connection_sock *icsk = inet_csk(sk);
793
794 if (icsk->icsk_af_ops->compat_setsockopt != NULL)
795 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
796 optval, optlen);
797 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
798 optval, optlen);
799}
800EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
801#endif