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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// 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);