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(addr: sk1_rcv_saddr6);
42 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(addr: 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(a1: sk1_rcv_saddr6, a2: 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(sk1_rcv_saddr6: &sk->sk_v6_rcv_saddr,
97 sk2_rcv_saddr6: inet6_rcv_saddr(sk: sk2),
98 sk1_rcv_saddr: sk->sk_rcv_saddr,
99 sk2_rcv_saddr: sk2->sk_rcv_saddr,
100 ipv6_only_sock(sk),
101 ipv6_only_sock(sk2),
102 match_sk1_wildcard: match_wildcard,
103 match_sk2_wildcard: match_wildcard);
104#endif
105 return ipv4_rcv_saddr_equal(sk1_rcv_saddr: sk->sk_rcv_saddr, sk2_rcv_saddr: sk2->sk_rcv_saddr,
106 ipv6_only_sock(sk2), match_sk1_wildcard: match_wildcard,
107 match_sk2_wildcard: 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(a: &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(net: sock_net(sk), low: &lo, high: &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(addr: &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(left: sk_uid, right: sock_i_uid(sk: 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(left: sk_uid, right: sock_i_uid(sk: 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(a: &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(sk2, &(__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(sk: (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, sk_uid: 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, sk_uid: 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(sk: (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(lock: &head2->lock);
309
310 inet_bind_bucket_for_each(tb2, &head2->chain) {
311 if (!inet_bind2_bucket_match_addr_any(tb: tb2, net, port, l3mdev, sk))
312 continue;
313
314 if (!inet_bhash2_conflict(sk, tb2, sk_uid: uid, relax, reuseport_cb_ok, reuseport_ok))
315 continue;
316
317 conflict = true;
318 break;
319 }
320
321 spin_unlock(lock: &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(ceil: 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, lport: port,
378 bhash_size: hinfo->bhash_size)];
379 spin_lock_bh(lock: &head->lock);
380 if (inet_use_bhash2_on_bind(sk)) {
381 if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, relax, reuseport_ok: false))
382 goto next_port;
383 }
384
385 head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
386 spin_lock(lock: &head2->lock);
387 tb2 = inet_bind2_bucket_find(head: 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, reuseport_ok: false))
392 goto success;
393 spin_unlock(lock: &head2->lock);
394 goto next_port;
395 }
396 tb = NULL;
397 goto success;
398next_port:
399 spin_unlock_bh(lock: &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(left: tb->fastuid, right: 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(sk1_rcv_saddr6: &tb->fast_v6_rcv_saddr,
450 sk2_rcv_saddr6: inet6_rcv_saddr(sk),
451 sk1_rcv_saddr: tb->fast_rcv_saddr,
452 sk2_rcv_saddr: sk->sk_rcv_saddr,
453 sk1_ipv6only: tb->fast_ipv6_only,
454 ipv6_only_sock(sk), match_sk1_wildcard: true, match_sk2_wildcard: false);
455#endif
456 return ipv4_rcv_saddr_equal(sk1_rcv_saddr: tb->fast_rcv_saddr, sk2_rcv_saddr: sk->sk_rcv_saddr,
457 ipv6_only_sock(sk), match_sk1_wildcard: true, match_sk2_wildcard: 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(h: &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_ret: &tb, tb2_ret: &tb2, head2_ret: &head2, port_ret: &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, lport: port,
542 bhash_size: hinfo->bhash_size)];
543 spin_lock_bh(lock: &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(cachep: hinfo->bind_bucket_cachep, net,
551 head, snum: port, l3mdev);
552 if (!tb)
553 goto fail_unlock;
554 bhash_created = true;
555 }
556
557 if (!found_port) {
558 if (!hlist_empty(h: &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, relax: true, reuseport_ok: true))
567 goto fail_unlock;
568 }
569
570 head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
571 spin_lock(lock: &head2->lock);
572 head2_lock_acquired = true;
573 tb2 = inet_bind2_bucket_find(head: head2, net, port, l3mdev, sk);
574 }
575
576 if (!tb2) {
577 tb2 = inet_bind2_bucket_create(cachep: hinfo->bind2_bucket_cachep,
578 net, head: 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, relax: true, reuseport_ok: 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(cachep: hinfo->bind2_bucket_cachep, tb: tb2);
602 if (bhash_created)
603 inet_bind_bucket_destroy(cachep: hinfo->bind_bucket_cachep, tb);
604 }
605 if (head2_lock_acquired)
606 spin_unlock(lock: &head2->lock);
607 spin_unlock_bh(lock: &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(wq_head: sk_sleep(sk), wq_entry: &wait,
638 TASK_INTERRUPTIBLE);
639 release_sock(sk);
640 if (reqsk_queue_empty(queue: &icsk->icsk_accept_queue))
641 timeo = schedule_timeout(timeout: timeo);
642 sched_annotate_sleep();
643 lock_sock(sk);
644 err = 0;
645 if (!reqsk_queue_empty(queue: &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(wq_head: sk_sleep(sk), wq_entry: &wait);
658 return err;
659}
660
661/*
662 * This will accept the next outstanding connection.
663 */
664struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
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, noblock: 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, parent: sk);
695 newsk = req->sk;
696
697 if (sk->sk_protocol == IPPROTO_TCP &&
698 tcp_rsk(req)->tfo_listener) {
699 spin_lock_bh(lock: &queue->fastopenq.lock);
700 if (tcp_rsk(req)->tfo_listener) {
701 /* We are still waiting for the final ACK from 3WHS
702 * so can't free req now. Instead, we set req->sk to
703 * NULL to signify that the child socket is taken
704 * so reqsk_fastopen_remove() will free the req
705 * when 3WHS finishes (or is aborted).
706 */
707 req->sk = NULL;
708 req = NULL;
709 }
710 spin_unlock_bh(lock: &queue->fastopenq.lock);
711 }
712
713out:
714 release_sock(sk);
715 if (newsk && mem_cgroup_sockets_enabled) {
716 int amt = 0;
717
718 /* atomically get the memory usage, set and charge the
719 * newsk->sk_memcg.
720 */
721 lock_sock(sk: newsk);
722
723 mem_cgroup_sk_alloc(sk: newsk);
724 if (newsk->sk_memcg) {
725 /* The socket has not been accepted yet, no need
726 * to look at newsk->sk_wmem_queued.
727 */
728 amt = sk_mem_pages(amt: newsk->sk_forward_alloc +
729 atomic_read(v: &newsk->sk_rmem_alloc));
730 }
731
732 if (amt)
733 mem_cgroup_charge_skmem(memcg: newsk->sk_memcg, nr_pages: amt,
734 GFP_KERNEL | __GFP_NOFAIL);
735
736 release_sock(sk: newsk);
737 }
738 if (req)
739 reqsk_put(req);
740
741 if (newsk)
742 inet_init_csk_locks(sk: newsk);
743
744 return newsk;
745out_err:
746 newsk = NULL;
747 req = NULL;
748 *err = error;
749 goto out;
750}
751EXPORT_SYMBOL(inet_csk_accept);
752
753/*
754 * Using different timers for retransmit, delayed acks and probes
755 * We may wish use just one timer maintaining a list of expire jiffies
756 * to optimize.
757 */
758void inet_csk_init_xmit_timers(struct sock *sk,
759 void (*retransmit_handler)(struct timer_list *t),
760 void (*delack_handler)(struct timer_list *t),
761 void (*keepalive_handler)(struct timer_list *t))
762{
763 struct inet_connection_sock *icsk = inet_csk(sk);
764
765 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
766 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
767 timer_setup(&sk->sk_timer, keepalive_handler, 0);
768 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
769}
770EXPORT_SYMBOL(inet_csk_init_xmit_timers);
771
772void inet_csk_clear_xmit_timers(struct sock *sk)
773{
774 struct inet_connection_sock *icsk = inet_csk(sk);
775
776 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
777
778 sk_stop_timer(sk, timer: &icsk->icsk_retransmit_timer);
779 sk_stop_timer(sk, timer: &icsk->icsk_delack_timer);
780 sk_stop_timer(sk, timer: &sk->sk_timer);
781}
782EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
783
784void inet_csk_clear_xmit_timers_sync(struct sock *sk)
785{
786 struct inet_connection_sock *icsk = inet_csk(sk);
787
788 /* ongoing timer handlers need to acquire socket lock. */
789 sock_not_owned_by_me(sk);
790
791 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
792
793 sk_stop_timer_sync(sk, timer: &icsk->icsk_retransmit_timer);
794 sk_stop_timer_sync(sk, timer: &icsk->icsk_delack_timer);
795 sk_stop_timer_sync(sk, timer: &sk->sk_timer);
796}
797
798void inet_csk_delete_keepalive_timer(struct sock *sk)
799{
800 sk_stop_timer(sk, timer: &sk->sk_timer);
801}
802EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
803
804void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
805{
806 sk_reset_timer(sk, timer: &sk->sk_timer, expires: jiffies + len);
807}
808EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
809
810struct dst_entry *inet_csk_route_req(const struct sock *sk,
811 struct flowi4 *fl4,
812 const struct request_sock *req)
813{
814 const struct inet_request_sock *ireq = inet_rsk(sk: req);
815 struct net *net = read_pnet(pnet: &ireq->ireq_net);
816 struct ip_options_rcu *opt;
817 struct rtable *rt;
818
819 rcu_read_lock();
820 opt = rcu_dereference(ireq->ireq_opt);
821
822 flowi4_init_output(fl4, oif: ireq->ir_iif, mark: ireq->ir_mark,
823 tos: ip_sock_rt_tos(sk), scope: ip_sock_rt_scope(sk),
824 proto: sk->sk_protocol, flags: inet_sk_flowi_flags(sk),
825 daddr: (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
826 saddr: ireq->ir_loc_addr, dport: ireq->ir_rmt_port,
827 htons(ireq->ir_num), uid: sk->sk_uid);
828 security_req_classify_flow(req, flic: flowi4_to_flowi_common(fl4));
829 rt = ip_route_output_flow(net, flp: fl4, sk);
830 if (IS_ERR(ptr: rt))
831 goto no_route;
832 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
833 goto route_err;
834 rcu_read_unlock();
835 return &rt->dst;
836
837route_err:
838 ip_rt_put(rt);
839no_route:
840 rcu_read_unlock();
841 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
842 return NULL;
843}
844EXPORT_SYMBOL_GPL(inet_csk_route_req);
845
846struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
847 struct sock *newsk,
848 const struct request_sock *req)
849{
850 const struct inet_request_sock *ireq = inet_rsk(sk: req);
851 struct net *net = read_pnet(pnet: &ireq->ireq_net);
852 struct inet_sock *newinet = inet_sk(newsk);
853 struct ip_options_rcu *opt;
854 struct flowi4 *fl4;
855 struct rtable *rt;
856
857 opt = rcu_dereference(ireq->ireq_opt);
858 fl4 = &newinet->cork.fl.u.ip4;
859
860 flowi4_init_output(fl4, oif: ireq->ir_iif, mark: ireq->ir_mark,
861 tos: ip_sock_rt_tos(sk), scope: ip_sock_rt_scope(sk),
862 proto: sk->sk_protocol, flags: inet_sk_flowi_flags(sk),
863 daddr: (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
864 saddr: ireq->ir_loc_addr, dport: ireq->ir_rmt_port,
865 htons(ireq->ir_num), uid: sk->sk_uid);
866 security_req_classify_flow(req, flic: flowi4_to_flowi_common(fl4));
867 rt = ip_route_output_flow(net, flp: fl4, sk);
868 if (IS_ERR(ptr: rt))
869 goto no_route;
870 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
871 goto route_err;
872 return &rt->dst;
873
874route_err:
875 ip_rt_put(rt);
876no_route:
877 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
878 return NULL;
879}
880EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
881
882/* Decide when to expire the request and when to resend SYN-ACK */
883static void syn_ack_recalc(struct request_sock *req,
884 const int max_syn_ack_retries,
885 const u8 rskq_defer_accept,
886 int *expire, int *resend)
887{
888 if (!rskq_defer_accept) {
889 *expire = req->num_timeout >= max_syn_ack_retries;
890 *resend = 1;
891 return;
892 }
893 *expire = req->num_timeout >= max_syn_ack_retries &&
894 (!inet_rsk(sk: req)->acked || req->num_timeout >= rskq_defer_accept);
895 /* Do not resend while waiting for data after ACK,
896 * start to resend on end of deferring period to give
897 * last chance for data or ACK to create established socket.
898 */
899 *resend = !inet_rsk(sk: req)->acked ||
900 req->num_timeout >= rskq_defer_accept - 1;
901}
902
903int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
904{
905 int err = req->rsk_ops->rtx_syn_ack(parent, req);
906
907 if (!err)
908 req->num_retrans++;
909 return err;
910}
911EXPORT_SYMBOL(inet_rtx_syn_ack);
912
913static struct request_sock *inet_reqsk_clone(struct request_sock *req,
914 struct sock *sk)
915{
916 struct sock *req_sk, *nreq_sk;
917 struct request_sock *nreq;
918
919 nreq = kmem_cache_alloc(cachep: req->rsk_ops->slab, GFP_ATOMIC | __GFP_NOWARN);
920 if (!nreq) {
921 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
922
923 /* paired with refcount_inc_not_zero() in reuseport_migrate_sock() */
924 sock_put(sk);
925 return NULL;
926 }
927
928 req_sk = req_to_sk(req);
929 nreq_sk = req_to_sk(req: nreq);
930
931 memcpy(nreq_sk, req_sk,
932 offsetof(struct sock, sk_dontcopy_begin));
933 unsafe_memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end,
934 req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end),
935 /* alloc is larger than struct, see above */);
936
937 sk_node_init(node: &nreq_sk->sk_node);
938 nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping;
939#ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
940 nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping;
941#endif
942 nreq_sk->sk_incoming_cpu = req_sk->sk_incoming_cpu;
943
944 nreq->rsk_listener = sk;
945
946 /* We need not acquire fastopenq->lock
947 * because the child socket is locked in inet_csk_listen_stop().
948 */
949 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req: nreq)->tfo_listener)
950 rcu_assign_pointer(tcp_sk(nreq->sk)->fastopen_rsk, nreq);
951
952 return nreq;
953}
954
955static void reqsk_queue_migrated(struct request_sock_queue *queue,
956 const struct request_sock *req)
957{
958 if (req->num_timeout == 0)
959 atomic_inc(v: &queue->young);
960 atomic_inc(v: &queue->qlen);
961}
962
963static void reqsk_migrate_reset(struct request_sock *req)
964{
965 req->saved_syn = NULL;
966#if IS_ENABLED(CONFIG_IPV6)
967 inet_rsk(sk: req)->ipv6_opt = NULL;
968 inet_rsk(sk: req)->pktopts = NULL;
969#else
970 inet_rsk(req)->ireq_opt = NULL;
971#endif
972}
973
974/* return true if req was found in the ehash table */
975static bool reqsk_queue_unlink(struct request_sock *req)
976{
977 struct sock *sk = req_to_sk(req);
978 bool found = false;
979
980 if (sk_hashed(sk)) {
981 struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk);
982 spinlock_t *lock = inet_ehash_lockp(hashinfo, hash: req->rsk_hash);
983
984 spin_lock(lock);
985 found = __sk_nulls_del_node_init_rcu(sk);
986 spin_unlock(lock);
987 }
988 if (timer_pending(timer: &req->rsk_timer) && del_timer_sync(timer: &req->rsk_timer))
989 reqsk_put(req);
990 return found;
991}
992
993bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
994{
995 bool unlinked = reqsk_queue_unlink(req);
996
997 if (unlinked) {
998 reqsk_queue_removed(queue: &inet_csk(sk)->icsk_accept_queue, req);
999 reqsk_put(req);
1000 }
1001 return unlinked;
1002}
1003EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
1004
1005void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
1006{
1007 inet_csk_reqsk_queue_drop(sk, req);
1008 reqsk_put(req);
1009}
1010EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
1011
1012static void reqsk_timer_handler(struct timer_list *t)
1013{
1014 struct request_sock *req = from_timer(req, t, rsk_timer);
1015 struct request_sock *nreq = NULL, *oreq = req;
1016 struct sock *sk_listener = req->rsk_listener;
1017 struct inet_connection_sock *icsk;
1018 struct request_sock_queue *queue;
1019 struct net *net;
1020 int max_syn_ack_retries, qlen, expire = 0, resend = 0;
1021
1022 if (inet_sk_state_load(sk: sk_listener) != TCP_LISTEN) {
1023 struct sock *nsk;
1024
1025 nsk = reuseport_migrate_sock(sk: sk_listener, migrating_sk: req_to_sk(req), NULL);
1026 if (!nsk)
1027 goto drop;
1028
1029 nreq = inet_reqsk_clone(req, sk: nsk);
1030 if (!nreq)
1031 goto drop;
1032
1033 /* The new timer for the cloned req can decrease the 2
1034 * by calling inet_csk_reqsk_queue_drop_and_put(), so
1035 * hold another count to prevent use-after-free and
1036 * call reqsk_put() just before return.
1037 */
1038 refcount_set(r: &nreq->rsk_refcnt, n: 2 + 1);
1039 timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
1040 reqsk_queue_migrated(queue: &inet_csk(sk: nsk)->icsk_accept_queue, req);
1041
1042 req = nreq;
1043 sk_listener = nsk;
1044 }
1045
1046 icsk = inet_csk(sk: sk_listener);
1047 net = sock_net(sk: sk_listener);
1048 max_syn_ack_retries = READ_ONCE(icsk->icsk_syn_retries) ? :
1049 READ_ONCE(net->ipv4.sysctl_tcp_synack_retries);
1050 /* Normally all the openreqs are young and become mature
1051 * (i.e. converted to established socket) for first timeout.
1052 * If synack was not acknowledged for 1 second, it means
1053 * one of the following things: synack was lost, ack was lost,
1054 * rtt is high or nobody planned to ack (i.e. synflood).
1055 * When server is a bit loaded, queue is populated with old
1056 * open requests, reducing effective size of queue.
1057 * When server is well loaded, queue size reduces to zero
1058 * after several minutes of work. It is not synflood,
1059 * it is normal operation. The solution is pruning
1060 * too old entries overriding normal timeout, when
1061 * situation becomes dangerous.
1062 *
1063 * Essentially, we reserve half of room for young
1064 * embrions; and abort old ones without pity, if old
1065 * ones are about to clog our table.
1066 */
1067 queue = &icsk->icsk_accept_queue;
1068 qlen = reqsk_queue_len(queue);
1069 if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {
1070 int young = reqsk_queue_len_young(queue) << 1;
1071
1072 while (max_syn_ack_retries > 2) {
1073 if (qlen < young)
1074 break;
1075 max_syn_ack_retries--;
1076 young <<= 1;
1077 }
1078 }
1079 syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept),
1080 expire: &expire, resend: &resend);
1081 req->rsk_ops->syn_ack_timeout(req);
1082 if (!expire &&
1083 (!resend ||
1084 !inet_rtx_syn_ack(sk_listener, req) ||
1085 inet_rsk(sk: req)->acked)) {
1086 if (req->num_timeout++ == 0)
1087 atomic_dec(v: &queue->young);
1088 mod_timer(timer: &req->rsk_timer, expires: jiffies + reqsk_timeout(req, TCP_RTO_MAX));
1089
1090 if (!nreq)
1091 return;
1092
1093 if (!inet_ehash_insert(sk: req_to_sk(req: nreq), osk: req_to_sk(req: oreq), NULL)) {
1094 /* delete timer */
1095 inet_csk_reqsk_queue_drop(sk_listener, nreq);
1096 goto no_ownership;
1097 }
1098
1099 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQSUCCESS);
1100 reqsk_migrate_reset(req: oreq);
1101 reqsk_queue_removed(queue: &inet_csk(sk: oreq->rsk_listener)->icsk_accept_queue, req: oreq);
1102 reqsk_put(req: oreq);
1103
1104 reqsk_put(req: nreq);
1105 return;
1106 }
1107
1108 /* Even if we can clone the req, we may need not retransmit any more
1109 * SYN+ACKs (nreq->num_timeout > max_syn_ack_retries, etc), or another
1110 * CPU may win the "own_req" race so that inet_ehash_insert() fails.
1111 */
1112 if (nreq) {
1113 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQFAILURE);
1114no_ownership:
1115 reqsk_migrate_reset(req: nreq);
1116 reqsk_queue_removed(queue, req: nreq);
1117 __reqsk_free(req: nreq);
1118 }
1119
1120drop:
1121 inet_csk_reqsk_queue_drop_and_put(oreq->rsk_listener, oreq);
1122}
1123
1124static void reqsk_queue_hash_req(struct request_sock *req,
1125 unsigned long timeout)
1126{
1127 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
1128 mod_timer(timer: &req->rsk_timer, expires: jiffies + timeout);
1129
1130 inet_ehash_insert(sk: req_to_sk(req), NULL, NULL);
1131 /* before letting lookups find us, make sure all req fields
1132 * are committed to memory and refcnt initialized.
1133 */
1134 smp_wmb();
1135 refcount_set(r: &req->rsk_refcnt, n: 2 + 1);
1136}
1137
1138void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
1139 unsigned long timeout)
1140{
1141 reqsk_queue_hash_req(req, timeout);
1142 inet_csk_reqsk_queue_added(sk);
1143}
1144EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
1145
1146static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk,
1147 const gfp_t priority)
1148{
1149 struct inet_connection_sock *icsk = inet_csk(sk: newsk);
1150
1151 if (!icsk->icsk_ulp_ops)
1152 return;
1153
1154 icsk->icsk_ulp_ops->clone(req, newsk, priority);
1155}
1156
1157/**
1158 * inet_csk_clone_lock - clone an inet socket, and lock its clone
1159 * @sk: the socket to clone
1160 * @req: request_sock
1161 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
1162 *
1163 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
1164 */
1165struct sock *inet_csk_clone_lock(const struct sock *sk,
1166 const struct request_sock *req,
1167 const gfp_t priority)
1168{
1169 struct sock *newsk = sk_clone_lock(sk, priority);
1170
1171 if (newsk) {
1172 struct inet_connection_sock *newicsk = inet_csk(sk: newsk);
1173
1174 inet_sk_set_state(sk: newsk, state: TCP_SYN_RECV);
1175 newicsk->icsk_bind_hash = NULL;
1176 newicsk->icsk_bind2_hash = NULL;
1177
1178 inet_sk(newsk)->inet_dport = inet_rsk(sk: req)->ir_rmt_port;
1179 inet_sk(newsk)->inet_num = inet_rsk(sk: req)->ir_num;
1180 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
1181
1182 /* listeners have SOCK_RCU_FREE, not the children */
1183 sock_reset_flag(sk: newsk, flag: SOCK_RCU_FREE);
1184
1185 inet_sk(newsk)->mc_list = NULL;
1186
1187 newsk->sk_mark = inet_rsk(sk: req)->ir_mark;
1188 atomic64_set(v: &newsk->sk_cookie,
1189 i: atomic64_read(v: &inet_rsk(sk: req)->ir_cookie));
1190
1191 newicsk->icsk_retransmits = 0;
1192 newicsk->icsk_backoff = 0;
1193 newicsk->icsk_probes_out = 0;
1194 newicsk->icsk_probes_tstamp = 0;
1195
1196 /* Deinitialize accept_queue to trap illegal accesses. */
1197 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
1198
1199 inet_clone_ulp(req, newsk, priority);
1200
1201 security_inet_csk_clone(newsk, req);
1202 }
1203 return newsk;
1204}
1205EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
1206
1207/*
1208 * At this point, there should be no process reference to this
1209 * socket, and thus no user references at all. Therefore we
1210 * can assume the socket waitqueue is inactive and nobody will
1211 * try to jump onto it.
1212 */
1213void inet_csk_destroy_sock(struct sock *sk)
1214{
1215 WARN_ON(sk->sk_state != TCP_CLOSE);
1216 WARN_ON(!sock_flag(sk, SOCK_DEAD));
1217
1218 /* It cannot be in hash table! */
1219 WARN_ON(!sk_unhashed(sk));
1220
1221 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
1222 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
1223
1224 sk->sk_prot->destroy(sk);
1225
1226 sk_stream_kill_queues(sk);
1227
1228 xfrm_sk_free_policy(sk);
1229
1230 this_cpu_dec(*sk->sk_prot->orphan_count);
1231
1232 sock_put(sk);
1233}
1234EXPORT_SYMBOL(inet_csk_destroy_sock);
1235
1236/* This function allows to force a closure of a socket after the call to
1237 * tcp/dccp_create_openreq_child().
1238 */
1239void inet_csk_prepare_forced_close(struct sock *sk)
1240 __releases(&sk->sk_lock.slock)
1241{
1242 /* sk_clone_lock locked the socket and set refcnt to 2 */
1243 bh_unlock_sock(sk);
1244 sock_put(sk);
1245 inet_csk_prepare_for_destroy_sock(sk);
1246 inet_sk(sk)->inet_num = 0;
1247}
1248EXPORT_SYMBOL(inet_csk_prepare_forced_close);
1249
1250static int inet_ulp_can_listen(const struct sock *sk)
1251{
1252 const struct inet_connection_sock *icsk = inet_csk(sk);
1253
1254 if (icsk->icsk_ulp_ops && !icsk->icsk_ulp_ops->clone)
1255 return -EINVAL;
1256
1257 return 0;
1258}
1259
1260int inet_csk_listen_start(struct sock *sk)
1261{
1262 struct inet_connection_sock *icsk = inet_csk(sk);
1263 struct inet_sock *inet = inet_sk(sk);
1264 int err;
1265
1266 err = inet_ulp_can_listen(sk);
1267 if (unlikely(err))
1268 return err;
1269
1270 reqsk_queue_alloc(queue: &icsk->icsk_accept_queue);
1271
1272 sk->sk_ack_backlog = 0;
1273 inet_csk_delack_init(sk);
1274
1275 /* There is race window here: we announce ourselves listening,
1276 * but this transition is still not validated by get_port().
1277 * It is OK, because this socket enters to hash table only
1278 * after validation is complete.
1279 */
1280 inet_sk_state_store(sk, newstate: TCP_LISTEN);
1281 err = sk->sk_prot->get_port(sk, inet->inet_num);
1282 if (!err) {
1283 inet->inet_sport = htons(inet->inet_num);
1284
1285 sk_dst_reset(sk);
1286 err = sk->sk_prot->hash(sk);
1287
1288 if (likely(!err))
1289 return 0;
1290 }
1291
1292 inet_sk_set_state(sk, state: TCP_CLOSE);
1293 return err;
1294}
1295EXPORT_SYMBOL_GPL(inet_csk_listen_start);
1296
1297static void inet_child_forget(struct sock *sk, struct request_sock *req,
1298 struct sock *child)
1299{
1300 sk->sk_prot->disconnect(child, O_NONBLOCK);
1301
1302 sock_orphan(sk: child);
1303
1304 this_cpu_inc(*sk->sk_prot->orphan_count);
1305
1306 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
1307 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req);
1308 BUG_ON(sk != req->rsk_listener);
1309
1310 /* Paranoid, to prevent race condition if
1311 * an inbound pkt destined for child is
1312 * blocked by sock lock in tcp_v4_rcv().
1313 * Also to satisfy an assertion in
1314 * tcp_v4_destroy_sock().
1315 */
1316 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL);
1317 }
1318 inet_csk_destroy_sock(child);
1319}
1320
1321struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
1322 struct request_sock *req,
1323 struct sock *child)
1324{
1325 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
1326
1327 spin_lock(lock: &queue->rskq_lock);
1328 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1329 inet_child_forget(sk, req, child);
1330 child = NULL;
1331 } else {
1332 req->sk = child;
1333 req->dl_next = NULL;
1334 if (queue->rskq_accept_head == NULL)
1335 WRITE_ONCE(queue->rskq_accept_head, req);
1336 else
1337 queue->rskq_accept_tail->dl_next = req;
1338 queue->rskq_accept_tail = req;
1339 sk_acceptq_added(sk);
1340 }
1341 spin_unlock(lock: &queue->rskq_lock);
1342 return child;
1343}
1344EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
1345
1346struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
1347 struct request_sock *req, bool own_req)
1348{
1349 if (own_req) {
1350 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
1351 reqsk_queue_removed(queue: &inet_csk(sk: req->rsk_listener)->icsk_accept_queue, req);
1352
1353 if (sk != req->rsk_listener) {
1354 /* another listening sk has been selected,
1355 * migrate the req to it.
1356 */
1357 struct request_sock *nreq;
1358
1359 /* hold a refcnt for the nreq->rsk_listener
1360 * which is assigned in inet_reqsk_clone()
1361 */
1362 sock_hold(sk);
1363 nreq = inet_reqsk_clone(req, sk);
1364 if (!nreq) {
1365 inet_child_forget(sk, req, child);
1366 goto child_put;
1367 }
1368
1369 refcount_set(r: &nreq->rsk_refcnt, n: 1);
1370 if (inet_csk_reqsk_queue_add(sk, nreq, child)) {
1371 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQSUCCESS);
1372 reqsk_migrate_reset(req);
1373 reqsk_put(req);
1374 return child;
1375 }
1376
1377 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
1378 reqsk_migrate_reset(req: nreq);
1379 __reqsk_free(req: nreq);
1380 } else if (inet_csk_reqsk_queue_add(sk, req, child)) {
1381 return child;
1382 }
1383 }
1384 /* Too bad, another child took ownership of the request, undo. */
1385child_put:
1386 bh_unlock_sock(child);
1387 sock_put(sk: child);
1388 return NULL;
1389}
1390EXPORT_SYMBOL(inet_csk_complete_hashdance);
1391
1392/*
1393 * This routine closes sockets which have been at least partially
1394 * opened, but not yet accepted.
1395 */
1396void inet_csk_listen_stop(struct sock *sk)
1397{
1398 struct inet_connection_sock *icsk = inet_csk(sk);
1399 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
1400 struct request_sock *next, *req;
1401
1402 /* Following specs, it would be better either to send FIN
1403 * (and enter FIN-WAIT-1, it is normal close)
1404 * or to send active reset (abort).
1405 * Certainly, it is pretty dangerous while synflood, but it is
1406 * bad justification for our negligence 8)
1407 * To be honest, we are not able to make either
1408 * of the variants now. --ANK
1409 */
1410 while ((req = reqsk_queue_remove(queue, parent: sk)) != NULL) {
1411 struct sock *child = req->sk, *nsk;
1412 struct request_sock *nreq;
1413
1414 local_bh_disable();
1415 bh_lock_sock(child);
1416 WARN_ON(sock_owned_by_user(child));
1417 sock_hold(sk: child);
1418
1419 nsk = reuseport_migrate_sock(sk, migrating_sk: child, NULL);
1420 if (nsk) {
1421 nreq = inet_reqsk_clone(req, sk: nsk);
1422 if (nreq) {
1423 refcount_set(r: &nreq->rsk_refcnt, n: 1);
1424
1425 if (inet_csk_reqsk_queue_add(nsk, nreq, child)) {
1426 __NET_INC_STATS(sock_net(nsk),
1427 LINUX_MIB_TCPMIGRATEREQSUCCESS);
1428 reqsk_migrate_reset(req);
1429 } else {
1430 __NET_INC_STATS(sock_net(nsk),
1431 LINUX_MIB_TCPMIGRATEREQFAILURE);
1432 reqsk_migrate_reset(req: nreq);
1433 __reqsk_free(req: nreq);
1434 }
1435
1436 /* inet_csk_reqsk_queue_add() has already
1437 * called inet_child_forget() on failure case.
1438 */
1439 goto skip_child_forget;
1440 }
1441 }
1442
1443 inet_child_forget(sk, req, child);
1444skip_child_forget:
1445 reqsk_put(req);
1446 bh_unlock_sock(child);
1447 local_bh_enable();
1448 sock_put(sk: child);
1449
1450 cond_resched();
1451 }
1452 if (queue->fastopenq.rskq_rst_head) {
1453 /* Free all the reqs queued in rskq_rst_head. */
1454 spin_lock_bh(lock: &queue->fastopenq.lock);
1455 req = queue->fastopenq.rskq_rst_head;
1456 queue->fastopenq.rskq_rst_head = NULL;
1457 spin_unlock_bh(lock: &queue->fastopenq.lock);
1458 while (req != NULL) {
1459 next = req->dl_next;
1460 reqsk_put(req);
1461 req = next;
1462 }
1463 }
1464 WARN_ON_ONCE(sk->sk_ack_backlog);
1465}
1466EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1467
1468void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1469{
1470 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1471 const struct inet_sock *inet = inet_sk(sk);
1472
1473 sin->sin_family = AF_INET;
1474 sin->sin_addr.s_addr = inet->inet_daddr;
1475 sin->sin_port = inet->inet_dport;
1476}
1477EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1478
1479static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1480{
1481 const struct inet_sock *inet = inet_sk(sk);
1482 const struct ip_options_rcu *inet_opt;
1483 __be32 daddr = inet->inet_daddr;
1484 struct flowi4 *fl4;
1485 struct rtable *rt;
1486
1487 rcu_read_lock();
1488 inet_opt = rcu_dereference(inet->inet_opt);
1489 if (inet_opt && inet_opt->opt.srr)
1490 daddr = inet_opt->opt.faddr;
1491 fl4 = &fl->u.ip4;
1492 rt = ip_route_output_ports(net: sock_net(sk), fl4, sk, daddr,
1493 saddr: inet->inet_saddr, dport: inet->inet_dport,
1494 sport: inet->inet_sport, proto: sk->sk_protocol,
1495 tos: ip_sock_rt_tos(sk), oif: sk->sk_bound_dev_if);
1496 if (IS_ERR(ptr: rt))
1497 rt = NULL;
1498 if (rt)
1499 sk_setup_caps(sk, dst: &rt->dst);
1500 rcu_read_unlock();
1501
1502 return &rt->dst;
1503}
1504
1505struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1506{
1507 struct dst_entry *dst = __sk_dst_check(sk, cookie: 0);
1508 struct inet_sock *inet = inet_sk(sk);
1509
1510 if (!dst) {
1511 dst = inet_csk_rebuild_route(sk, fl: &inet->cork.fl);
1512 if (!dst)
1513 goto out;
1514 }
1515 dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
1516
1517 dst = __sk_dst_check(sk, cookie: 0);
1518 if (!dst)
1519 dst = inet_csk_rebuild_route(sk, fl: &inet->cork.fl);
1520out:
1521 return dst;
1522}
1523EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);
1524

source code of linux/net/ipv4/inet_connection_sock.c