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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
120/**
121 * inet_sk_get_local_port_range - fetch ephemeral ports range
122 * @sk: socket
123 * @low: pointer to low port
124 * @high: pointer to high port
125 *
126 * Fetch netns port range (/proc/sys/net/ipv4/ip_local_port_range)
127 * Range can be overridden if socket got IP_LOCAL_PORT_RANGE option.
128 * Returns true if IP_LOCAL_PORT_RANGE was set on this socket.
129 */
130bool inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high)
131{
132 int lo, hi, sk_lo, sk_hi;
133 bool local_range = false;
134 u32 sk_range;
135
136 inet_get_local_port_range(sock_net(sk), &lo, &hi);
137
138 sk_range = READ_ONCE(inet_sk(sk)->local_port_range);
139 if (unlikely(sk_range)) {
140 sk_lo = sk_range & 0xffff;
141 sk_hi = sk_range >> 16;
142
143 if (lo <= sk_lo && sk_lo <= hi)
144 lo = sk_lo;
145 if (lo <= sk_hi && sk_hi <= hi)
146 hi = sk_hi;
147 local_range = true;
148 }
149
150 *low = lo;
151 *high = hi;
152 return local_range;
153}
154EXPORT_SYMBOL(inet_sk_get_local_port_range);
155
156static bool inet_use_bhash2_on_bind(const struct sock *sk)
157{
158#if IS_ENABLED(CONFIG_IPV6)
159 if (sk->sk_family == AF_INET6) {
160 int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr);
161
162 if (addr_type == IPV6_ADDR_ANY)
163 return false;
164
165 if (addr_type != IPV6_ADDR_MAPPED)
166 return true;
167 }
168#endif
169 return sk->sk_rcv_saddr != htonl(INADDR_ANY);
170}
171
172static bool inet_bind_conflict(const struct sock *sk, struct sock *sk2,
173 kuid_t sk_uid, bool relax,
174 bool reuseport_cb_ok, bool reuseport_ok)
175{
176 int bound_dev_if2;
177
178 if (sk == sk2)
179 return false;
180
181 bound_dev_if2 = READ_ONCE(sk2->sk_bound_dev_if);
182
183 if (!sk->sk_bound_dev_if || !bound_dev_if2 ||
184 sk->sk_bound_dev_if == bound_dev_if2) {
185 if (sk->sk_reuse && sk2->sk_reuse &&
186 sk2->sk_state != TCP_LISTEN) {
187 if (!relax || (!reuseport_ok && sk->sk_reuseport &&
188 sk2->sk_reuseport && reuseport_cb_ok &&
189 (sk2->sk_state == TCP_TIME_WAIT ||
190 uid_eq(sk_uid, sock_i_uid(sk2)))))
191 return true;
192 } else if (!reuseport_ok || !sk->sk_reuseport ||
193 !sk2->sk_reuseport || !reuseport_cb_ok ||
194 (sk2->sk_state != TCP_TIME_WAIT &&
195 !uid_eq(sk_uid, sock_i_uid(sk2)))) {
196 return true;
197 }
198 }
199 return false;
200}
201
202static bool __inet_bhash2_conflict(const struct sock *sk, struct sock *sk2,
203 kuid_t sk_uid, bool relax,
204 bool reuseport_cb_ok, bool reuseport_ok)
205{
206 if (ipv6_only_sock(sk2)) {
207 if (sk->sk_family == AF_INET)
208 return false;
209
210#if IS_ENABLED(CONFIG_IPV6)
211 if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
212 return false;
213#endif
214 }
215
216 return inet_bind_conflict(sk, sk2, sk_uid, relax,
217 reuseport_cb_ok, reuseport_ok);
218}
219
220static bool inet_bhash2_conflict(const struct sock *sk,
221 const struct inet_bind2_bucket *tb2,
222 kuid_t sk_uid,
223 bool relax, bool reuseport_cb_ok,
224 bool reuseport_ok)
225{
226 struct sock *sk2;
227
228 sk_for_each_bound(sk2, &tb2->owners) {
229 if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax,
230 reuseport_cb_ok, reuseport_ok))
231 return true;
232 }
233
234 return false;
235}
236
237#define sk_for_each_bound_bhash(__sk, __tb2, __tb) \
238 hlist_for_each_entry(__tb2, &(__tb)->bhash2, bhash_node) \
239 sk_for_each_bound((__sk), &(__tb2)->owners)
240
241/* This should be called only when the tb and tb2 hashbuckets' locks are held */
242static int inet_csk_bind_conflict(const struct sock *sk,
243 const struct inet_bind_bucket *tb,
244 const struct inet_bind2_bucket *tb2, /* may be null */
245 bool relax, bool reuseport_ok)
246{
247 kuid_t uid = sock_i_uid((struct sock *)sk);
248 struct sock_reuseport *reuseport_cb;
249 bool reuseport_cb_ok;
250 struct sock *sk2;
251
252 rcu_read_lock();
253 reuseport_cb = rcu_dereference(sk->sk_reuseport_cb);
254 /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */
255 reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks);
256 rcu_read_unlock();
257
258 /* Conflicts with an existing IPV6_ADDR_ANY (if ipv6) or INADDR_ANY (if
259 * ipv4) should have been checked already. We need to do these two
260 * checks separately because their spinlocks have to be acquired/released
261 * independently of each other, to prevent possible deadlocks
262 */
263 if (inet_use_bhash2_on_bind(sk))
264 return tb2 && inet_bhash2_conflict(sk, tb2, uid, relax,
265 reuseport_cb_ok, reuseport_ok);
266
267 /* Unlike other sk lookup places we do not check
268 * for sk_net here, since _all_ the socks listed
269 * in tb->owners and tb2->owners list belong
270 * to the same net - the one this bucket belongs to.
271 */
272 sk_for_each_bound_bhash(sk2, tb2, tb) {
273 if (!inet_bind_conflict(sk, sk2, uid, relax, reuseport_cb_ok, reuseport_ok))
274 continue;
275
276 if (inet_rcv_saddr_equal(sk, sk2, true))
277 return true;
278 }
279
280 return false;
281}
282
283/* Determine if there is a bind conflict with an existing IPV6_ADDR_ANY (if ipv6) or
284 * INADDR_ANY (if ipv4) socket.
285 *
286 * Caller must hold bhash hashbucket lock with local bh disabled, to protect
287 * against concurrent binds on the port for addr any
288 */
289static bool inet_bhash2_addr_any_conflict(const struct sock *sk, int port, int l3mdev,
290 bool relax, bool reuseport_ok)
291{
292 kuid_t uid = sock_i_uid((struct sock *)sk);
293 const struct net *net = sock_net(sk);
294 struct sock_reuseport *reuseport_cb;
295 struct inet_bind_hashbucket *head2;
296 struct inet_bind2_bucket *tb2;
297 bool conflict = false;
298 bool reuseport_cb_ok;
299
300 rcu_read_lock();
301 reuseport_cb = rcu_dereference(sk->sk_reuseport_cb);
302 /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */
303 reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks);
304 rcu_read_unlock();
305
306 head2 = inet_bhash2_addr_any_hashbucket(sk, net, port);
307
308 spin_lock(&head2->lock);
309
310 inet_bind_bucket_for_each(tb2, &head2->chain) {
311 if (!inet_bind2_bucket_match_addr_any(tb2, net, port, l3mdev, sk))
312 continue;
313
314 if (!inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok, reuseport_ok))
315 continue;
316
317 conflict = true;
318 break;
319 }
320
321 spin_unlock(&head2->lock);
322
323 return conflict;
324}
325
326/*
327 * Find an open port number for the socket. Returns with the
328 * inet_bind_hashbucket locks held if successful.
329 */
330static struct inet_bind_hashbucket *
331inet_csk_find_open_port(const struct sock *sk, struct inet_bind_bucket **tb_ret,
332 struct inet_bind2_bucket **tb2_ret,
333 struct inet_bind_hashbucket **head2_ret, int *port_ret)
334{
335 struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
336 int i, low, high, attempt_half, port, l3mdev;
337 struct inet_bind_hashbucket *head, *head2;
338 struct net *net = sock_net(sk);
339 struct inet_bind2_bucket *tb2;
340 struct inet_bind_bucket *tb;
341 u32 remaining, offset;
342 bool relax = false;
343
344 l3mdev = inet_sk_bound_l3mdev(sk);
345ports_exhausted:
346 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
347other_half_scan:
348 inet_sk_get_local_port_range(sk, &low, &high);
349 high++; /* [32768, 60999] -> [32768, 61000[ */
350 if (high - low < 4)
351 attempt_half = 0;
352 if (attempt_half) {
353 int half = low + (((high - low) >> 2) << 1);
354
355 if (attempt_half == 1)
356 high = half;
357 else
358 low = half;
359 }
360 remaining = high - low;
361 if (likely(remaining > 1))
362 remaining &= ~1U;
363
364 offset = get_random_u32_below(remaining);
365 /* __inet_hash_connect() favors ports having @low parity
366 * We do the opposite to not pollute connect() users.
367 */
368 offset |= 1U;
369
370other_parity_scan:
371 port = low + offset;
372 for (i = 0; i < remaining; i += 2, port += 2) {
373 if (unlikely(port >= high))
374 port -= remaining;
375 if (inet_is_local_reserved_port(net, port))
376 continue;
377 head = &hinfo->bhash[inet_bhashfn(net, port,
378 hinfo->bhash_size)];
379 spin_lock_bh(&head->lock);
380 if (inet_use_bhash2_on_bind(sk)) {
381 if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, relax, false))
382 goto next_port;
383 }
384
385 head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
386 spin_lock(&head2->lock);
387 tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk);
388 inet_bind_bucket_for_each(tb, &head->chain)
389 if (inet_bind_bucket_match(tb, net, port, l3mdev)) {
390 if (!inet_csk_bind_conflict(sk, tb, tb2,
391 relax, false))
392 goto success;
393 spin_unlock(&head2->lock);
394 goto next_port;
395 }
396 tb = NULL;
397 goto success;
398next_port:
399 spin_unlock_bh(&head->lock);
400 cond_resched();
401 }
402
403 offset--;
404 if (!(offset & 1))
405 goto other_parity_scan;
406
407 if (attempt_half == 1) {
408 /* OK we now try the upper half of the range */
409 attempt_half = 2;
410 goto other_half_scan;
411 }
412
413 if (READ_ONCE(net->ipv4.sysctl_ip_autobind_reuse) && !relax) {
414 /* We still have a chance to connect to different destinations */
415 relax = true;
416 goto ports_exhausted;
417 }
418 return NULL;
419success:
420 *port_ret = port;
421 *tb_ret = tb;
422 *tb2_ret = tb2;
423 *head2_ret = head2;
424 return head;
425}
426
427static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
428 struct sock *sk)
429{
430 kuid_t uid = sock_i_uid(sk);
431
432 if (tb->fastreuseport <= 0)
433 return 0;
434 if (!sk->sk_reuseport)
435 return 0;
436 if (rcu_access_pointer(sk->sk_reuseport_cb))
437 return 0;
438 if (!uid_eq(tb->fastuid, uid))
439 return 0;
440 /* We only need to check the rcv_saddr if this tb was once marked
441 * without fastreuseport and then was reset, as we can only know that
442 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
443 * owners list.
444 */
445 if (tb->fastreuseport == FASTREUSEPORT_ANY)
446 return 1;
447#if IS_ENABLED(CONFIG_IPV6)
448 if (tb->fast_sk_family == AF_INET6)
449 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
450 inet6_rcv_saddr(sk),
451 tb->fast_rcv_saddr,
452 sk->sk_rcv_saddr,
453 tb->fast_ipv6_only,
454 ipv6_only_sock(sk), true, false);
455#endif
456 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
457 ipv6_only_sock(sk), true, false);
458}
459
460void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
461 struct sock *sk)
462{
463 kuid_t uid = sock_i_uid(sk);
464 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
465
466 if (hlist_empty(&tb->bhash2)) {
467 tb->fastreuse = reuse;
468 if (sk->sk_reuseport) {
469 tb->fastreuseport = FASTREUSEPORT_ANY;
470 tb->fastuid = uid;
471 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
472 tb->fast_ipv6_only = ipv6_only_sock(sk);
473 tb->fast_sk_family = sk->sk_family;
474#if IS_ENABLED(CONFIG_IPV6)
475 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
476#endif
477 } else {
478 tb->fastreuseport = 0;
479 }
480 } else {
481 if (!reuse)
482 tb->fastreuse = 0;
483 if (sk->sk_reuseport) {
484 /* We didn't match or we don't have fastreuseport set on
485 * the tb, but we have sk_reuseport set on this socket
486 * and we know that there are no bind conflicts with
487 * this socket in this tb, so reset our tb's reuseport
488 * settings so that any subsequent sockets that match
489 * our current socket will be put on the fast path.
490 *
491 * If we reset we need to set FASTREUSEPORT_STRICT so we
492 * do extra checking for all subsequent sk_reuseport
493 * socks.
494 */
495 if (!sk_reuseport_match(tb, sk)) {
496 tb->fastreuseport = FASTREUSEPORT_STRICT;
497 tb->fastuid = uid;
498 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
499 tb->fast_ipv6_only = ipv6_only_sock(sk);
500 tb->fast_sk_family = sk->sk_family;
501#if IS_ENABLED(CONFIG_IPV6)
502 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
503#endif
504 }
505 } else {
506 tb->fastreuseport = 0;
507 }
508 }
509}
510
511/* Obtain a reference to a local port for the given sock,
512 * if snum is zero it means select any available local port.
513 * We try to allocate an odd port (and leave even ports for connect())
514 */
515int inet_csk_get_port(struct sock *sk, unsigned short snum)
516{
517 struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
518 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
519 bool found_port = false, check_bind_conflict = true;
520 bool bhash_created = false, bhash2_created = false;
521 int ret = -EADDRINUSE, port = snum, l3mdev;
522 struct inet_bind_hashbucket *head, *head2;
523 struct inet_bind2_bucket *tb2 = NULL;
524 struct inet_bind_bucket *tb = NULL;
525 bool head2_lock_acquired = false;
526 struct net *net = sock_net(sk);
527
528 l3mdev = inet_sk_bound_l3mdev(sk);
529
530 if (!port) {
531 head = inet_csk_find_open_port(sk, &tb, &tb2, &head2, &port);
532 if (!head)
533 return ret;
534
535 head2_lock_acquired = true;
536
537 if (tb && tb2)
538 goto success;
539 found_port = true;
540 } else {
541 head = &hinfo->bhash[inet_bhashfn(net, port,
542 hinfo->bhash_size)];
543 spin_lock_bh(&head->lock);
544 inet_bind_bucket_for_each(tb, &head->chain)
545 if (inet_bind_bucket_match(tb, net, port, l3mdev))
546 break;
547 }
548
549 if (!tb) {
550 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, net,
551 head, port, l3mdev);
552 if (!tb)
553 goto fail_unlock;
554 bhash_created = true;
555 }
556
557 if (!found_port) {
558 if (!hlist_empty(&tb->bhash2)) {
559 if (sk->sk_reuse == SK_FORCE_REUSE ||
560 (tb->fastreuse > 0 && reuse) ||
561 sk_reuseport_match(tb, sk))
562 check_bind_conflict = false;
563 }
564
565 if (check_bind_conflict && inet_use_bhash2_on_bind(sk)) {
566 if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, true, true))
567 goto fail_unlock;
568 }
569
570 head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
571 spin_lock(&head2->lock);
572 head2_lock_acquired = true;
573 tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk);
574 }
575
576 if (!tb2) {
577 tb2 = inet_bind2_bucket_create(hinfo->bind2_bucket_cachep,
578 net, head2, tb, sk);
579 if (!tb2)
580 goto fail_unlock;
581 bhash2_created = true;
582 }
583
584 if (!found_port && check_bind_conflict) {
585 if (inet_csk_bind_conflict(sk, tb, tb2, true, true))
586 goto fail_unlock;
587 }
588
589success:
590 inet_csk_update_fastreuse(tb, sk);
591
592 if (!inet_csk(sk)->icsk_bind_hash)
593 inet_bind_hash(sk, tb, tb2, port);
594 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
595 WARN_ON(inet_csk(sk)->icsk_bind2_hash != tb2);
596 ret = 0;
597
598fail_unlock:
599 if (ret) {
600 if (bhash2_created)
601 inet_bind2_bucket_destroy(hinfo->bind2_bucket_cachep, tb2);
602 if (bhash_created)
603 inet_bind_bucket_destroy(hinfo->bind_bucket_cachep, tb);
604 }
605 if (head2_lock_acquired)
606 spin_unlock(&head2->lock);
607 spin_unlock_bh(&head->lock);
608 return ret;
609}
610EXPORT_SYMBOL_GPL(inet_csk_get_port);
611
612/*
613 * Wait for an incoming connection, avoid race conditions. This must be called
614 * with the socket locked.
615 */
616static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
617{
618 struct inet_connection_sock *icsk = inet_csk(sk);
619 DEFINE_WAIT(wait);
620 int err;
621
622 /*
623 * True wake-one mechanism for incoming connections: only
624 * one process gets woken up, not the 'whole herd'.
625 * Since we do not 'race & poll' for established sockets
626 * anymore, the common case will execute the loop only once.
627 *
628 * Subtle issue: "add_wait_queue_exclusive()" will be added
629 * after any current non-exclusive waiters, and we know that
630 * it will always _stay_ after any new non-exclusive waiters
631 * because all non-exclusive waiters are added at the
632 * beginning of the wait-queue. As such, it's ok to "drop"
633 * our exclusiveness temporarily when we get woken up without
634 * having to remove and re-insert us on the wait queue.
635 */
636 for (;;) {
637 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
638 TASK_INTERRUPTIBLE);
639 release_sock(sk);
640 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
641 timeo = schedule_timeout(timeo);
642 sched_annotate_sleep();
643 lock_sock(sk);
644 err = 0;
645 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
646 break;
647 err = -EINVAL;
648 if (sk->sk_state != TCP_LISTEN)
649 break;
650 err = sock_intr_errno(timeo);
651 if (signal_pending(current))
652 break;
653 err = -EAGAIN;
654 if (!timeo)
655 break;
656 }
657 finish_wait(sk_sleep(sk), &wait);
658 return err;
659}
660
661/*
662 * This will accept the next outstanding connection.
663 */
664struct sock *inet_csk_accept(struct sock *sk, struct proto_accept_arg *arg)
665{
666 struct inet_connection_sock *icsk = inet_csk(sk);
667 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
668 struct request_sock *req;
669 struct sock *newsk;
670 int error;
671
672 lock_sock(sk);
673
674 /* We need to make sure that this socket is listening,
675 * and that it has something pending.
676 */
677 error = -EINVAL;
678 if (sk->sk_state != TCP_LISTEN)
679 goto out_err;
680
681 /* Find already established connection */
682 if (reqsk_queue_empty(queue)) {
683 long timeo = sock_rcvtimeo(sk, arg->flags & O_NONBLOCK);
684
685 /* If this is a non blocking socket don't sleep */
686 error = -EAGAIN;
687 if (!timeo)
688 goto out_err;
689
690 error = inet_csk_wait_for_connect(sk, timeo);
691 if (error)
692 goto out_err;
693 }
694 req = reqsk_queue_remove(queue, sk);
695 arg->is_empty = reqsk_queue_empty(queue);
696 newsk = req->sk;
697
698 if (sk->sk_protocol == IPPROTO_TCP &&
699 tcp_rsk(req)->tfo_listener) {
700 spin_lock_bh(&queue->fastopenq.lock);
701 if (tcp_rsk(req)->tfo_listener) {
702 /* We are still waiting for the final ACK from 3WHS
703 * so can't free req now. Instead, we set req->sk to
704 * NULL to signify that the child socket is taken
705 * so reqsk_fastopen_remove() will free the req
706 * when 3WHS finishes (or is aborted).
707 */
708 req->sk = NULL;
709 req = NULL;
710 }
711 spin_unlock_bh(&queue->fastopenq.lock);
712 }
713
714out:
715 release_sock(sk);
716 if (newsk && mem_cgroup_sockets_enabled) {
717 gfp_t gfp = GFP_KERNEL | __GFP_NOFAIL;
718 int amt = 0;
719
720 /* atomically get the memory usage, set and charge the
721 * newsk->sk_memcg.
722 */
723 lock_sock(newsk);
724
725 mem_cgroup_sk_alloc(newsk);
726 if (newsk->sk_memcg) {
727 /* The socket has not been accepted yet, no need
728 * to look at newsk->sk_wmem_queued.
729 */
730 amt = sk_mem_pages(newsk->sk_forward_alloc +
731 atomic_read(&newsk->sk_rmem_alloc));
732 }
733
734 if (amt)
735 mem_cgroup_charge_skmem(newsk->sk_memcg, amt, gfp);
736 kmem_cache_charge(newsk, gfp);
737
738 release_sock(newsk);
739 }
740 if (req)
741 reqsk_put(req);
742
743 if (newsk)
744 inet_init_csk_locks(newsk);
745
746 return newsk;
747out_err:
748 newsk = NULL;
749 req = NULL;
750 arg->err = error;
751 goto out;
752}
753EXPORT_SYMBOL(inet_csk_accept);
754
755/*
756 * Using different timers for retransmit, delayed acks and probes
757 * We may wish use just one timer maintaining a list of expire jiffies
758 * to optimize.
759 */
760void inet_csk_init_xmit_timers(struct sock *sk,
761 void (*retransmit_handler)(struct timer_list *t),
762 void (*delack_handler)(struct timer_list *t),
763 void (*keepalive_handler)(struct timer_list *t))
764{
765 struct inet_connection_sock *icsk = inet_csk(sk);
766
767 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
768 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
769 timer_setup(&sk->sk_timer, keepalive_handler, 0);
770 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
771}
772EXPORT_SYMBOL(inet_csk_init_xmit_timers);
773
774void inet_csk_clear_xmit_timers(struct sock *sk)
775{
776 struct inet_connection_sock *icsk = inet_csk(sk);
777
778 smp_store_release(&icsk->icsk_pending, 0);
779 smp_store_release(&icsk->icsk_ack.pending, 0);
780
781 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
782 sk_stop_timer(sk, &icsk->icsk_delack_timer);
783 sk_stop_timer(sk, &sk->sk_timer);
784}
785EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
786
787void inet_csk_clear_xmit_timers_sync(struct sock *sk)
788{
789 struct inet_connection_sock *icsk = inet_csk(sk);
790
791 /* ongoing timer handlers need to acquire socket lock. */
792 sock_not_owned_by_me(sk);
793
794 smp_store_release(&icsk->icsk_pending, 0);
795 smp_store_release(&icsk->icsk_ack.pending, 0);
796
797 sk_stop_timer_sync(sk, &icsk->icsk_retransmit_timer);
798 sk_stop_timer_sync(sk, &icsk->icsk_delack_timer);
799 sk_stop_timer_sync(sk, &sk->sk_timer);
800}
801
802void inet_csk_delete_keepalive_timer(struct sock *sk)
803{
804 sk_stop_timer(sk, &sk->sk_timer);
805}
806EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
807
808void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
809{
810 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
811}
812EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
813
814struct dst_entry *inet_csk_route_req(const struct sock *sk,
815 struct flowi4 *fl4,
816 const struct request_sock *req)
817{
818 const struct inet_request_sock *ireq = inet_rsk(req);
819 struct net *net = read_pnet(&ireq->ireq_net);
820 struct ip_options_rcu *opt;
821 struct rtable *rt;
822
823 rcu_read_lock();
824 opt = rcu_dereference(ireq->ireq_opt);
825
826 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
827 ip_sock_rt_tos(sk), ip_sock_rt_scope(sk),
828 sk->sk_protocol, inet_sk_flowi_flags(sk),
829 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
830 ireq->ir_loc_addr, ireq->ir_rmt_port,
831 htons(ireq->ir_num), sk->sk_uid);
832 security_req_classify_flow(req, flowi4_to_flowi_common(fl4));
833 rt = ip_route_output_flow(net, fl4, sk);
834 if (IS_ERR(rt))
835 goto no_route;
836 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
837 goto route_err;
838 rcu_read_unlock();
839 return &rt->dst;
840
841route_err:
842 ip_rt_put(rt);
843no_route:
844 rcu_read_unlock();
845 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
846 return NULL;
847}
848EXPORT_SYMBOL_GPL(inet_csk_route_req);
849
850struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
851 struct sock *newsk,
852 const struct request_sock *req)
853{
854 const struct inet_request_sock *ireq = inet_rsk(req);
855 struct net *net = read_pnet(&ireq->ireq_net);
856 struct inet_sock *newinet = inet_sk(newsk);
857 struct ip_options_rcu *opt;
858 struct flowi4 *fl4;
859 struct rtable *rt;
860
861 opt = rcu_dereference(ireq->ireq_opt);
862 fl4 = &newinet->cork.fl.u.ip4;
863
864 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
865 ip_sock_rt_tos(sk), ip_sock_rt_scope(sk),
866 sk->sk_protocol, inet_sk_flowi_flags(sk),
867 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
868 ireq->ir_loc_addr, ireq->ir_rmt_port,
869 htons(ireq->ir_num), sk->sk_uid);
870 security_req_classify_flow(req, flowi4_to_flowi_common(fl4));
871 rt = ip_route_output_flow(net, fl4, sk);
872 if (IS_ERR(rt))
873 goto no_route;
874 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
875 goto route_err;
876 return &rt->dst;
877
878route_err:
879 ip_rt_put(rt);
880no_route:
881 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
882 return NULL;
883}
884EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
885
886/* Decide when to expire the request and when to resend SYN-ACK */
887static void syn_ack_recalc(struct request_sock *req,
888 const int max_syn_ack_retries,
889 const u8 rskq_defer_accept,
890 int *expire, int *resend)
891{
892 if (!rskq_defer_accept) {
893 *expire = req->num_timeout >= max_syn_ack_retries;
894 *resend = 1;
895 return;
896 }
897 *expire = req->num_timeout >= max_syn_ack_retries &&
898 (!inet_rsk(req)->acked || req->num_timeout >= rskq_defer_accept);
899 /* Do not resend while waiting for data after ACK,
900 * start to resend on end of deferring period to give
901 * last chance for data or ACK to create established socket.
902 */
903 *resend = !inet_rsk(req)->acked ||
904 req->num_timeout >= rskq_defer_accept - 1;
905}
906
907int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
908{
909 int err = req->rsk_ops->rtx_syn_ack(parent, req);
910
911 if (!err)
912 req->num_retrans++;
913 return err;
914}
915EXPORT_SYMBOL(inet_rtx_syn_ack);
916
917static struct request_sock *
918reqsk_alloc_noprof(const struct request_sock_ops *ops, struct sock *sk_listener,
919 bool attach_listener)
920{
921 struct request_sock *req;
922
923 req = kmem_cache_alloc_noprof(ops->slab, GFP_ATOMIC | __GFP_NOWARN);
924 if (!req)
925 return NULL;
926 req->rsk_listener = NULL;
927 if (attach_listener) {
928 if (unlikely(!refcount_inc_not_zero(&sk_listener->sk_refcnt))) {
929 kmem_cache_free(ops->slab, req);
930 return NULL;
931 }
932 req->rsk_listener = sk_listener;
933 }
934 req->rsk_ops = ops;
935 req_to_sk(req)->sk_prot = sk_listener->sk_prot;
936 sk_node_init(&req_to_sk(req)->sk_node);
937 sk_tx_queue_clear(req_to_sk(req));
938 req->saved_syn = NULL;
939 req->syncookie = 0;
940 req->timeout = 0;
941 req->num_timeout = 0;
942 req->num_retrans = 0;
943 req->sk = NULL;
944 refcount_set(&req->rsk_refcnt, 0);
945
946 return req;
947}
948#define reqsk_alloc(...) alloc_hooks(reqsk_alloc_noprof(__VA_ARGS__))
949
950struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
951 struct sock *sk_listener,
952 bool attach_listener)
953{
954 struct request_sock *req = reqsk_alloc(ops, sk_listener,
955 attach_listener);
956
957 if (req) {
958 struct inet_request_sock *ireq = inet_rsk(req);
959
960 ireq->ireq_opt = NULL;
961#if IS_ENABLED(CONFIG_IPV6)
962 ireq->pktopts = NULL;
963#endif
964 atomic64_set(&ireq->ir_cookie, 0);
965 ireq->ireq_state = TCP_NEW_SYN_RECV;
966 write_pnet(&ireq->ireq_net, sock_net(sk_listener));
967 ireq->ireq_family = sk_listener->sk_family;
968 req->timeout = TCP_TIMEOUT_INIT;
969 }
970
971 return req;
972}
973EXPORT_SYMBOL(inet_reqsk_alloc);
974
975static struct request_sock *inet_reqsk_clone(struct request_sock *req,
976 struct sock *sk)
977{
978 struct sock *req_sk, *nreq_sk;
979 struct request_sock *nreq;
980
981 nreq = kmem_cache_alloc(req->rsk_ops->slab, GFP_ATOMIC | __GFP_NOWARN);
982 if (!nreq) {
983 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
984
985 /* paired with refcount_inc_not_zero() in reuseport_migrate_sock() */
986 sock_put(sk);
987 return NULL;
988 }
989
990 req_sk = req_to_sk(req);
991 nreq_sk = req_to_sk(nreq);
992
993 memcpy(nreq_sk, req_sk,
994 offsetof(struct sock, sk_dontcopy_begin));
995 unsafe_memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end,
996 req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end),
997 /* alloc is larger than struct, see above */);
998
999 sk_node_init(&nreq_sk->sk_node);
1000 nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping;
1001#ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
1002 nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping;
1003#endif
1004 nreq_sk->sk_incoming_cpu = req_sk->sk_incoming_cpu;
1005
1006 nreq->rsk_listener = sk;
1007
1008 /* We need not acquire fastopenq->lock
1009 * because the child socket is locked in inet_csk_listen_stop().
1010 */
1011 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(nreq)->tfo_listener)
1012 rcu_assign_pointer(tcp_sk(nreq->sk)->fastopen_rsk, nreq);
1013
1014 return nreq;
1015}
1016
1017static void reqsk_queue_migrated(struct request_sock_queue *queue,
1018 const struct request_sock *req)
1019{
1020 if (req->num_timeout == 0)
1021 atomic_inc(&queue->young);
1022 atomic_inc(&queue->qlen);
1023}
1024
1025static void reqsk_migrate_reset(struct request_sock *req)
1026{
1027 req->saved_syn = NULL;
1028#if IS_ENABLED(CONFIG_IPV6)
1029 inet_rsk(req)->ipv6_opt = NULL;
1030 inet_rsk(req)->pktopts = NULL;
1031#else
1032 inet_rsk(req)->ireq_opt = NULL;
1033#endif
1034}
1035
1036/* return true if req was found in the ehash table */
1037static bool reqsk_queue_unlink(struct request_sock *req)
1038{
1039 struct sock *sk = req_to_sk(req);
1040 bool found = false;
1041
1042 if (sk_hashed(sk)) {
1043 struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk);
1044 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
1045
1046 spin_lock(lock);
1047 found = __sk_nulls_del_node_init_rcu(sk);
1048 spin_unlock(lock);
1049 }
1050
1051 return found;
1052}
1053
1054static bool __inet_csk_reqsk_queue_drop(struct sock *sk,
1055 struct request_sock *req,
1056 bool from_timer)
1057{
1058 bool unlinked = reqsk_queue_unlink(req);
1059
1060 if (!from_timer && timer_delete_sync(&req->rsk_timer))
1061 reqsk_put(req);
1062
1063 if (unlinked) {
1064 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
1065 reqsk_put(req);
1066 }
1067
1068 return unlinked;
1069}
1070
1071bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
1072{
1073 return __inet_csk_reqsk_queue_drop(sk, req, false);
1074}
1075EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
1076
1077void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
1078{
1079 inet_csk_reqsk_queue_drop(sk, req);
1080 reqsk_put(req);
1081}
1082EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
1083
1084static void reqsk_timer_handler(struct timer_list *t)
1085{
1086 struct request_sock *req = from_timer(req, t, rsk_timer);
1087 struct request_sock *nreq = NULL, *oreq = req;
1088 struct sock *sk_listener = req->rsk_listener;
1089 struct inet_connection_sock *icsk;
1090 struct request_sock_queue *queue;
1091 struct net *net;
1092 int max_syn_ack_retries, qlen, expire = 0, resend = 0;
1093
1094 if (inet_sk_state_load(sk_listener) != TCP_LISTEN) {
1095 struct sock *nsk;
1096
1097 nsk = reuseport_migrate_sock(sk_listener, req_to_sk(req), NULL);
1098 if (!nsk)
1099 goto drop;
1100
1101 nreq = inet_reqsk_clone(req, nsk);
1102 if (!nreq)
1103 goto drop;
1104
1105 /* The new timer for the cloned req can decrease the 2
1106 * by calling inet_csk_reqsk_queue_drop_and_put(), so
1107 * hold another count to prevent use-after-free and
1108 * call reqsk_put() just before return.
1109 */
1110 refcount_set(&nreq->rsk_refcnt, 2 + 1);
1111 timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
1112 reqsk_queue_migrated(&inet_csk(nsk)->icsk_accept_queue, req);
1113
1114 req = nreq;
1115 sk_listener = nsk;
1116 }
1117
1118 icsk = inet_csk(sk_listener);
1119 net = sock_net(sk_listener);
1120 max_syn_ack_retries = READ_ONCE(icsk->icsk_syn_retries) ? :
1121 READ_ONCE(net->ipv4.sysctl_tcp_synack_retries);
1122 /* Normally all the openreqs are young and become mature
1123 * (i.e. converted to established socket) for first timeout.
1124 * If synack was not acknowledged for 1 second, it means
1125 * one of the following things: synack was lost, ack was lost,
1126 * rtt is high or nobody planned to ack (i.e. synflood).
1127 * When server is a bit loaded, queue is populated with old
1128 * open requests, reducing effective size of queue.
1129 * When server is well loaded, queue size reduces to zero
1130 * after several minutes of work. It is not synflood,
1131 * it is normal operation. The solution is pruning
1132 * too old entries overriding normal timeout, when
1133 * situation becomes dangerous.
1134 *
1135 * Essentially, we reserve half of room for young
1136 * embrions; and abort old ones without pity, if old
1137 * ones are about to clog our table.
1138 */
1139 queue = &icsk->icsk_accept_queue;
1140 qlen = reqsk_queue_len(queue);
1141 if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {
1142 int young = reqsk_queue_len_young(queue) << 1;
1143
1144 while (max_syn_ack_retries > 2) {
1145 if (qlen < young)
1146 break;
1147 max_syn_ack_retries--;
1148 young <<= 1;
1149 }
1150 }
1151 syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept),
1152 &expire, &resend);
1153 req->rsk_ops->syn_ack_timeout(req);
1154 if (!expire &&
1155 (!resend ||
1156 !inet_rtx_syn_ack(sk_listener, req) ||
1157 inet_rsk(req)->acked)) {
1158 if (req->num_timeout++ == 0)
1159 atomic_dec(&queue->young);
1160 mod_timer(&req->rsk_timer, jiffies + reqsk_timeout(req, TCP_RTO_MAX));
1161
1162 if (!nreq)
1163 return;
1164
1165 if (!inet_ehash_insert(req_to_sk(nreq), req_to_sk(oreq), NULL)) {
1166 /* delete timer */
1167 __inet_csk_reqsk_queue_drop(sk_listener, nreq, true);
1168 goto no_ownership;
1169 }
1170
1171 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQSUCCESS);
1172 reqsk_migrate_reset(oreq);
1173 reqsk_queue_removed(&inet_csk(oreq->rsk_listener)->icsk_accept_queue, oreq);
1174 reqsk_put(oreq);
1175
1176 reqsk_put(nreq);
1177 return;
1178 }
1179
1180 /* Even if we can clone the req, we may need not retransmit any more
1181 * SYN+ACKs (nreq->num_timeout > max_syn_ack_retries, etc), or another
1182 * CPU may win the "own_req" race so that inet_ehash_insert() fails.
1183 */
1184 if (nreq) {
1185 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQFAILURE);
1186no_ownership:
1187 reqsk_migrate_reset(nreq);
1188 reqsk_queue_removed(queue, nreq);
1189 __reqsk_free(nreq);
1190 }
1191
1192drop:
1193 __inet_csk_reqsk_queue_drop(sk_listener, oreq, true);
1194 reqsk_put(oreq);
1195}
1196
1197static bool reqsk_queue_hash_req(struct request_sock *req,
1198 unsigned long timeout)
1199{
1200 bool found_dup_sk = false;
1201
1202 if (!inet_ehash_insert(req_to_sk(req), NULL, &found_dup_sk))
1203 return false;
1204
1205 /* The timer needs to be setup after a successful insertion. */
1206 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
1207 mod_timer(&req->rsk_timer, jiffies + timeout);
1208
1209 /* before letting lookups find us, make sure all req fields
1210 * are committed to memory and refcnt initialized.
1211 */
1212 smp_wmb();
1213 refcount_set(&req->rsk_refcnt, 2 + 1);
1214 return true;
1215}
1216
1217bool inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
1218 unsigned long timeout)
1219{
1220 if (!reqsk_queue_hash_req(req, timeout))
1221 return false;
1222
1223 inet_csk_reqsk_queue_added(sk);
1224 return true;
1225}
1226EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
1227
1228static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk,
1229 const gfp_t priority)
1230{
1231 struct inet_connection_sock *icsk = inet_csk(newsk);
1232
1233 if (!icsk->icsk_ulp_ops)
1234 return;
1235
1236 icsk->icsk_ulp_ops->clone(req, newsk, priority);
1237}
1238
1239/**
1240 * inet_csk_clone_lock - clone an inet socket, and lock its clone
1241 * @sk: the socket to clone
1242 * @req: request_sock
1243 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
1244 *
1245 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
1246 */
1247struct sock *inet_csk_clone_lock(const struct sock *sk,
1248 const struct request_sock *req,
1249 const gfp_t priority)
1250{
1251 struct sock *newsk = sk_clone_lock(sk, priority);
1252
1253 if (newsk) {
1254 struct inet_connection_sock *newicsk = inet_csk(newsk);
1255
1256 inet_sk_set_state(newsk, TCP_SYN_RECV);
1257 newicsk->icsk_bind_hash = NULL;
1258 newicsk->icsk_bind2_hash = NULL;
1259
1260 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
1261 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
1262 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
1263
1264 /* listeners have SOCK_RCU_FREE, not the children */
1265 sock_reset_flag(newsk, SOCK_RCU_FREE);
1266
1267 inet_sk(newsk)->mc_list = NULL;
1268
1269 newsk->sk_mark = inet_rsk(req)->ir_mark;
1270 atomic64_set(&newsk->sk_cookie,
1271 atomic64_read(&inet_rsk(req)->ir_cookie));
1272
1273 newicsk->icsk_retransmits = 0;
1274 newicsk->icsk_backoff = 0;
1275 newicsk->icsk_probes_out = 0;
1276 newicsk->icsk_probes_tstamp = 0;
1277
1278 /* Deinitialize accept_queue to trap illegal accesses. */
1279 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
1280
1281 inet_clone_ulp(req, newsk, priority);
1282
1283 security_inet_csk_clone(newsk, req);
1284 }
1285 return newsk;
1286}
1287EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
1288
1289/*
1290 * At this point, there should be no process reference to this
1291 * socket, and thus no user references at all. Therefore we
1292 * can assume the socket waitqueue is inactive and nobody will
1293 * try to jump onto it.
1294 */
1295void inet_csk_destroy_sock(struct sock *sk)
1296{
1297 WARN_ON(sk->sk_state != TCP_CLOSE);
1298 WARN_ON(!sock_flag(sk, SOCK_DEAD));
1299
1300 /* It cannot be in hash table! */
1301 WARN_ON(!sk_unhashed(sk));
1302
1303 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
1304 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
1305
1306 sk->sk_prot->destroy(sk);
1307
1308 sk_stream_kill_queues(sk);
1309
1310 xfrm_sk_free_policy(sk);
1311
1312 this_cpu_dec(*sk->sk_prot->orphan_count);
1313
1314 sock_put(sk);
1315}
1316EXPORT_SYMBOL(inet_csk_destroy_sock);
1317
1318/* This function allows to force a closure of a socket after the call to
1319 * tcp/dccp_create_openreq_child().
1320 */
1321void inet_csk_prepare_forced_close(struct sock *sk)
1322 __releases(&sk->sk_lock.slock)
1323{
1324 /* sk_clone_lock locked the socket and set refcnt to 2 */
1325 bh_unlock_sock(sk);
1326 sock_put(sk);
1327 inet_csk_prepare_for_destroy_sock(sk);
1328 inet_sk(sk)->inet_num = 0;
1329}
1330EXPORT_SYMBOL(inet_csk_prepare_forced_close);
1331
1332static int inet_ulp_can_listen(const struct sock *sk)
1333{
1334 const struct inet_connection_sock *icsk = inet_csk(sk);
1335
1336 if (icsk->icsk_ulp_ops && !icsk->icsk_ulp_ops->clone)
1337 return -EINVAL;
1338
1339 return 0;
1340}
1341
1342int inet_csk_listen_start(struct sock *sk)
1343{
1344 struct inet_connection_sock *icsk = inet_csk(sk);
1345 struct inet_sock *inet = inet_sk(sk);
1346 int err;
1347
1348 err = inet_ulp_can_listen(sk);
1349 if (unlikely(err))
1350 return err;
1351
1352 reqsk_queue_alloc(&icsk->icsk_accept_queue);
1353
1354 sk->sk_ack_backlog = 0;
1355 inet_csk_delack_init(sk);
1356
1357 /* There is race window here: we announce ourselves listening,
1358 * but this transition is still not validated by get_port().
1359 * It is OK, because this socket enters to hash table only
1360 * after validation is complete.
1361 */
1362 inet_sk_state_store(sk, TCP_LISTEN);
1363 err = sk->sk_prot->get_port(sk, inet->inet_num);
1364 if (!err) {
1365 inet->inet_sport = htons(inet->inet_num);
1366
1367 sk_dst_reset(sk);
1368 err = sk->sk_prot->hash(sk);
1369
1370 if (likely(!err))
1371 return 0;
1372 }
1373
1374 inet_sk_set_state(sk, TCP_CLOSE);
1375 return err;
1376}
1377EXPORT_SYMBOL_GPL(inet_csk_listen_start);
1378
1379static void inet_child_forget(struct sock *sk, struct request_sock *req,
1380 struct sock *child)
1381{
1382 sk->sk_prot->disconnect(child, O_NONBLOCK);
1383
1384 sock_orphan(child);
1385
1386 this_cpu_inc(*sk->sk_prot->orphan_count);
1387
1388 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
1389 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req);
1390 BUG_ON(sk != req->rsk_listener);
1391
1392 /* Paranoid, to prevent race condition if
1393 * an inbound pkt destined for child is
1394 * blocked by sock lock in tcp_v4_rcv().
1395 * Also to satisfy an assertion in
1396 * tcp_v4_destroy_sock().
1397 */
1398 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL);
1399 }
1400 inet_csk_destroy_sock(child);
1401}
1402
1403struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
1404 struct request_sock *req,
1405 struct sock *child)
1406{
1407 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
1408
1409 spin_lock(&queue->rskq_lock);
1410 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1411 inet_child_forget(sk, req, child);
1412 child = NULL;
1413 } else {
1414 req->sk = child;
1415 req->dl_next = NULL;
1416 if (queue->rskq_accept_head == NULL)
1417 WRITE_ONCE(queue->rskq_accept_head, req);
1418 else
1419 queue->rskq_accept_tail->dl_next = req;
1420 queue->rskq_accept_tail = req;
1421 sk_acceptq_added(sk);
1422 }
1423 spin_unlock(&queue->rskq_lock);
1424 return child;
1425}
1426EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
1427
1428struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
1429 struct request_sock *req, bool own_req)
1430{
1431 if (own_req) {
1432 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
1433 reqsk_queue_removed(&inet_csk(req->rsk_listener)->icsk_accept_queue, req);
1434
1435 if (sk != req->rsk_listener) {
1436 /* another listening sk has been selected,
1437 * migrate the req to it.
1438 */
1439 struct request_sock *nreq;
1440
1441 /* hold a refcnt for the nreq->rsk_listener
1442 * which is assigned in inet_reqsk_clone()
1443 */
1444 sock_hold(sk);
1445 nreq = inet_reqsk_clone(req, sk);
1446 if (!nreq) {
1447 inet_child_forget(sk, req, child);
1448 goto child_put;
1449 }
1450
1451 refcount_set(&nreq->rsk_refcnt, 1);
1452 if (inet_csk_reqsk_queue_add(sk, nreq, child)) {
1453 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQSUCCESS);
1454 reqsk_migrate_reset(req);
1455 reqsk_put(req);
1456 return child;
1457 }
1458
1459 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
1460 reqsk_migrate_reset(nreq);
1461 __reqsk_free(nreq);
1462 } else if (inet_csk_reqsk_queue_add(sk, req, child)) {
1463 return child;
1464 }
1465 }
1466 /* Too bad, another child took ownership of the request, undo. */
1467child_put:
1468 bh_unlock_sock(child);
1469 sock_put(child);
1470 return NULL;
1471}
1472EXPORT_SYMBOL(inet_csk_complete_hashdance);
1473
1474/*
1475 * This routine closes sockets which have been at least partially
1476 * opened, but not yet accepted.
1477 */
1478void inet_csk_listen_stop(struct sock *sk)
1479{
1480 struct inet_connection_sock *icsk = inet_csk(sk);
1481 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
1482 struct request_sock *next, *req;
1483
1484 /* Following specs, it would be better either to send FIN
1485 * (and enter FIN-WAIT-1, it is normal close)
1486 * or to send active reset (abort).
1487 * Certainly, it is pretty dangerous while synflood, but it is
1488 * bad justification for our negligence 8)
1489 * To be honest, we are not able to make either
1490 * of the variants now. --ANK
1491 */
1492 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
1493 struct sock *child = req->sk, *nsk;
1494 struct request_sock *nreq;
1495
1496 local_bh_disable();
1497 bh_lock_sock(child);
1498 WARN_ON(sock_owned_by_user(child));
1499 sock_hold(child);
1500
1501 nsk = reuseport_migrate_sock(sk, child, NULL);
1502 if (nsk) {
1503 nreq = inet_reqsk_clone(req, nsk);
1504 if (nreq) {
1505 refcount_set(&nreq->rsk_refcnt, 1);
1506
1507 if (inet_csk_reqsk_queue_add(nsk, nreq, child)) {
1508 __NET_INC_STATS(sock_net(nsk),
1509 LINUX_MIB_TCPMIGRATEREQSUCCESS);
1510 reqsk_migrate_reset(req);
1511 } else {
1512 __NET_INC_STATS(sock_net(nsk),
1513 LINUX_MIB_TCPMIGRATEREQFAILURE);
1514 reqsk_migrate_reset(nreq);
1515 __reqsk_free(nreq);
1516 }
1517
1518 /* inet_csk_reqsk_queue_add() has already
1519 * called inet_child_forget() on failure case.
1520 */
1521 goto skip_child_forget;
1522 }
1523 }
1524
1525 inet_child_forget(sk, req, child);
1526skip_child_forget:
1527 reqsk_put(req);
1528 bh_unlock_sock(child);
1529 local_bh_enable();
1530 sock_put(child);
1531
1532 cond_resched();
1533 }
1534 if (queue->fastopenq.rskq_rst_head) {
1535 /* Free all the reqs queued in rskq_rst_head. */
1536 spin_lock_bh(&queue->fastopenq.lock);
1537 req = queue->fastopenq.rskq_rst_head;
1538 queue->fastopenq.rskq_rst_head = NULL;
1539 spin_unlock_bh(&queue->fastopenq.lock);
1540 while (req != NULL) {
1541 next = req->dl_next;
1542 reqsk_put(req);
1543 req = next;
1544 }
1545 }
1546 WARN_ON_ONCE(sk->sk_ack_backlog);
1547}
1548EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1549
1550void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1551{
1552 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1553 const struct inet_sock *inet = inet_sk(sk);
1554
1555 sin->sin_family = AF_INET;
1556 sin->sin_addr.s_addr = inet->inet_daddr;
1557 sin->sin_port = inet->inet_dport;
1558}
1559EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1560
1561static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1562{
1563 const struct inet_sock *inet = inet_sk(sk);
1564 const struct ip_options_rcu *inet_opt;
1565 __be32 daddr = inet->inet_daddr;
1566 struct flowi4 *fl4;
1567 struct rtable *rt;
1568
1569 rcu_read_lock();
1570 inet_opt = rcu_dereference(inet->inet_opt);
1571 if (inet_opt && inet_opt->opt.srr)
1572 daddr = inet_opt->opt.faddr;
1573 fl4 = &fl->u.ip4;
1574 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
1575 inet->inet_saddr, inet->inet_dport,
1576 inet->inet_sport, sk->sk_protocol,
1577 ip_sock_rt_tos(sk), sk->sk_bound_dev_if);
1578 if (IS_ERR(rt))
1579 rt = NULL;
1580 if (rt)
1581 sk_setup_caps(sk, &rt->dst);
1582 rcu_read_unlock();
1583
1584 return &rt->dst;
1585}
1586
1587struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1588{
1589 struct dst_entry *dst = __sk_dst_check(sk, 0);
1590 struct inet_sock *inet = inet_sk(sk);
1591
1592 if (!dst) {
1593 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1594 if (!dst)
1595 goto out;
1596 }
1597 dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
1598
1599 dst = __sk_dst_check(sk, 0);
1600 if (!dst)
1601 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1602out:
1603 return dst;
1604}
1605EXPORT_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