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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Support for INET connection oriented protocols.
8 *
9 * Authors: See the TCP sources
10 */
11
12#include <linux/module.h>
13#include <linux/jhash.h>
14
15#include <net/inet_connection_sock.h>
16#include <net/inet_hashtables.h>
17#include <net/inet_timewait_sock.h>
18#include <net/ip.h>
19#include <net/route.h>
20#include <net/tcp_states.h>
21#include <net/xfrm.h>
22#include <net/tcp.h>
23#include <net/sock_reuseport.h>
24#include <net/addrconf.h>
25
26#if IS_ENABLED(CONFIG_IPV6)
27/* match_sk*_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses
28 * if IPv6 only, and any IPv4 addresses
29 * if not IPv6 only
30 * match_sk*_wildcard == false: addresses must be exactly the same, i.e.
31 * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
32 * and 0.0.0.0 equals to 0.0.0.0 only
33 */
34static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6,
35 const struct in6_addr *sk2_rcv_saddr6,
36 __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
37 bool sk1_ipv6only, bool sk2_ipv6only,
38 bool match_sk1_wildcard,
39 bool match_sk2_wildcard)
40{
41 int addr_type = ipv6_addr_type(sk1_rcv_saddr6);
42 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
43
44 /* if both are mapped, treat as IPv4 */
45 if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
46 if (!sk2_ipv6only) {
47 if (sk1_rcv_saddr == sk2_rcv_saddr)
48 return true;
49 return (match_sk1_wildcard && !sk1_rcv_saddr) ||
50 (match_sk2_wildcard && !sk2_rcv_saddr);
51 }
52 return false;
53 }
54
55 if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
56 return true;
57
58 if (addr_type2 == IPV6_ADDR_ANY && match_sk2_wildcard &&
59 !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
60 return true;
61
62 if (addr_type == IPV6_ADDR_ANY && match_sk1_wildcard &&
63 !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
64 return true;
65
66 if (sk2_rcv_saddr6 &&
67 ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6))
68 return true;
69
70 return false;
71}
72#endif
73
74/* match_sk*_wildcard == true: 0.0.0.0 equals to any IPv4 addresses
75 * match_sk*_wildcard == false: addresses must be exactly the same, i.e.
76 * 0.0.0.0 only equals to 0.0.0.0
77 */
78static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
79 bool sk2_ipv6only, bool match_sk1_wildcard,
80 bool match_sk2_wildcard)
81{
82 if (!sk2_ipv6only) {
83 if (sk1_rcv_saddr == sk2_rcv_saddr)
84 return true;
85 return (match_sk1_wildcard && !sk1_rcv_saddr) ||
86 (match_sk2_wildcard && !sk2_rcv_saddr);
87 }
88 return false;
89}
90
91bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
92 bool match_wildcard)
93{
94#if IS_ENABLED(CONFIG_IPV6)
95 if (sk->sk_family == AF_INET6)
96 return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr,
97 inet6_rcv_saddr(sk2),
98 sk->sk_rcv_saddr,
99 sk2->sk_rcv_saddr,
100 ipv6_only_sock(sk),
101 ipv6_only_sock(sk2),
102 match_wildcard,
103 match_wildcard);
104#endif
105 return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr,
106 ipv6_only_sock(sk2), match_wildcard,
107 match_wildcard);
108}
109EXPORT_SYMBOL(inet_rcv_saddr_equal);
110
111bool inet_rcv_saddr_any(const struct sock *sk)
112{
113#if IS_ENABLED(CONFIG_IPV6)
114 if (sk->sk_family == AF_INET6)
115 return ipv6_addr_any(&sk->sk_v6_rcv_saddr);
116#endif
117 return !sk->sk_rcv_saddr;
118}
119
120void inet_get_local_port_range(struct net *net, int *low, int *high)
121{
122 unsigned int seq;
123
124 do {
125 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
126
127 *low = net->ipv4.ip_local_ports.range[0];
128 *high = net->ipv4.ip_local_ports.range[1];
129 } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
130}
131EXPORT_SYMBOL(inet_get_local_port_range);
132
133static int inet_csk_bind_conflict(const struct sock *sk,
134 const struct inet_bind_bucket *tb,
135 bool relax, bool reuseport_ok)
136{
137 struct sock *sk2;
138 bool reuseport_cb_ok;
139 bool reuse = sk->sk_reuse;
140 bool reuseport = !!sk->sk_reuseport;
141 struct sock_reuseport *reuseport_cb;
142 kuid_t uid = sock_i_uid((struct sock *)sk);
143
144 rcu_read_lock();
145 reuseport_cb = rcu_dereference(sk->sk_reuseport_cb);
146 /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */
147 reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks);
148 rcu_read_unlock();
149
150 /*
151 * Unlike other sk lookup places we do not check
152 * for sk_net here, since _all_ the socks listed
153 * in tb->owners list belong to the same net - the
154 * one this bucket belongs to.
155 */
156
157 sk_for_each_bound(sk2, &tb->owners) {
158 if (sk != sk2 &&
159 (!sk->sk_bound_dev_if ||
160 !sk2->sk_bound_dev_if ||
161 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
162 if (reuse && sk2->sk_reuse &&
163 sk2->sk_state != TCP_LISTEN) {
164 if ((!relax ||
165 (!reuseport_ok &&
166 reuseport && sk2->sk_reuseport &&
167 reuseport_cb_ok &&
168 (sk2->sk_state == TCP_TIME_WAIT ||
169 uid_eq(uid, sock_i_uid(sk2))))) &&
170 inet_rcv_saddr_equal(sk, sk2, true))
171 break;
172 } else if (!reuseport_ok ||
173 !reuseport || !sk2->sk_reuseport ||
174 !reuseport_cb_ok ||
175 (sk2->sk_state != TCP_TIME_WAIT &&
176 !uid_eq(uid, sock_i_uid(sk2)))) {
177 if (inet_rcv_saddr_equal(sk, sk2, true))
178 break;
179 }
180 }
181 }
182 return sk2 != NULL;
183}
184
185/*
186 * Find an open port number for the socket. Returns with the
187 * inet_bind_hashbucket lock held.
188 */
189static struct inet_bind_hashbucket *
190inet_csk_find_open_port(struct sock *sk, struct inet_bind_bucket **tb_ret, int *port_ret)
191{
192 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
193 int port = 0;
194 struct inet_bind_hashbucket *head;
195 struct net *net = sock_net(sk);
196 bool relax = false;
197 int i, low, high, attempt_half;
198 struct inet_bind_bucket *tb;
199 u32 remaining, offset;
200 int l3mdev;
201
202 l3mdev = inet_sk_bound_l3mdev(sk);
203ports_exhausted:
204 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
205other_half_scan:
206 inet_get_local_port_range(net, &low, &high);
207 high++; /* [32768, 60999] -> [32768, 61000[ */
208 if (high - low < 4)
209 attempt_half = 0;
210 if (attempt_half) {
211 int half = low + (((high - low) >> 2) << 1);
212
213 if (attempt_half == 1)
214 high = half;
215 else
216 low = half;
217 }
218 remaining = high - low;
219 if (likely(remaining > 1))
220 remaining &= ~1U;
221
222 offset = prandom_u32() % remaining;
223 /* __inet_hash_connect() favors ports having @low parity
224 * We do the opposite to not pollute connect() users.
225 */
226 offset |= 1U;
227
228other_parity_scan:
229 port = low + offset;
230 for (i = 0; i < remaining; i += 2, port += 2) {
231 if (unlikely(port >= high))
232 port -= remaining;
233 if (inet_is_local_reserved_port(net, port))
234 continue;
235 head = &hinfo->bhash[inet_bhashfn(net, port,
236 hinfo->bhash_size)];
237 spin_lock_bh(&head->lock);
238 inet_bind_bucket_for_each(tb, &head->chain)
239 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
240 tb->port == port) {
241 if (!inet_csk_bind_conflict(sk, tb, relax, false))
242 goto success;
243 goto next_port;
244 }
245 tb = NULL;
246 goto success;
247next_port:
248 spin_unlock_bh(&head->lock);
249 cond_resched();
250 }
251
252 offset--;
253 if (!(offset & 1))
254 goto other_parity_scan;
255
256 if (attempt_half == 1) {
257 /* OK we now try the upper half of the range */
258 attempt_half = 2;
259 goto other_half_scan;
260 }
261
262 if (net->ipv4.sysctl_ip_autobind_reuse && !relax) {
263 /* We still have a chance to connect to different destinations */
264 relax = true;
265 goto ports_exhausted;
266 }
267 return NULL;
268success:
269 *port_ret = port;
270 *tb_ret = tb;
271 return head;
272}
273
274static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
275 struct sock *sk)
276{
277 kuid_t uid = sock_i_uid(sk);
278
279 if (tb->fastreuseport <= 0)
280 return 0;
281 if (!sk->sk_reuseport)
282 return 0;
283 if (rcu_access_pointer(sk->sk_reuseport_cb))
284 return 0;
285 if (!uid_eq(tb->fastuid, uid))
286 return 0;
287 /* We only need to check the rcv_saddr if this tb was once marked
288 * without fastreuseport and then was reset, as we can only know that
289 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
290 * owners list.
291 */
292 if (tb->fastreuseport == FASTREUSEPORT_ANY)
293 return 1;
294#if IS_ENABLED(CONFIG_IPV6)
295 if (tb->fast_sk_family == AF_INET6)
296 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
297 inet6_rcv_saddr(sk),
298 tb->fast_rcv_saddr,
299 sk->sk_rcv_saddr,
300 tb->fast_ipv6_only,
301 ipv6_only_sock(sk), true, false);
302#endif
303 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
304 ipv6_only_sock(sk), true, false);
305}
306
307void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
308 struct sock *sk)
309{
310 kuid_t uid = sock_i_uid(sk);
311 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
312
313 if (hlist_empty(&tb->owners)) {
314 tb->fastreuse = reuse;
315 if (sk->sk_reuseport) {
316 tb->fastreuseport = FASTREUSEPORT_ANY;
317 tb->fastuid = uid;
318 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
319 tb->fast_ipv6_only = ipv6_only_sock(sk);
320 tb->fast_sk_family = sk->sk_family;
321#if IS_ENABLED(CONFIG_IPV6)
322 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
323#endif
324 } else {
325 tb->fastreuseport = 0;
326 }
327 } else {
328 if (!reuse)
329 tb->fastreuse = 0;
330 if (sk->sk_reuseport) {
331 /* We didn't match or we don't have fastreuseport set on
332 * the tb, but we have sk_reuseport set on this socket
333 * and we know that there are no bind conflicts with
334 * this socket in this tb, so reset our tb's reuseport
335 * settings so that any subsequent sockets that match
336 * our current socket will be put on the fast path.
337 *
338 * If we reset we need to set FASTREUSEPORT_STRICT so we
339 * do extra checking for all subsequent sk_reuseport
340 * socks.
341 */
342 if (!sk_reuseport_match(tb, sk)) {
343 tb->fastreuseport = FASTREUSEPORT_STRICT;
344 tb->fastuid = uid;
345 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
346 tb->fast_ipv6_only = ipv6_only_sock(sk);
347 tb->fast_sk_family = sk->sk_family;
348#if IS_ENABLED(CONFIG_IPV6)
349 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
350#endif
351 }
352 } else {
353 tb->fastreuseport = 0;
354 }
355 }
356}
357
358/* Obtain a reference to a local port for the given sock,
359 * if snum is zero it means select any available local port.
360 * We try to allocate an odd port (and leave even ports for connect())
361 */
362int inet_csk_get_port(struct sock *sk, unsigned short snum)
363{
364 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
365 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
366 int ret = 1, port = snum;
367 struct inet_bind_hashbucket *head;
368 struct net *net = sock_net(sk);
369 struct inet_bind_bucket *tb = NULL;
370 int l3mdev;
371
372 l3mdev = inet_sk_bound_l3mdev(sk);
373
374 if (!port) {
375 head = inet_csk_find_open_port(sk, &tb, &port);
376 if (!head)
377 return ret;
378 if (!tb)
379 goto tb_not_found;
380 goto success;
381 }
382 head = &hinfo->bhash[inet_bhashfn(net, port,
383 hinfo->bhash_size)];
384 spin_lock_bh(&head->lock);
385 inet_bind_bucket_for_each(tb, &head->chain)
386 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
387 tb->port == port)
388 goto tb_found;
389tb_not_found:
390 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
391 net, head, port, l3mdev);
392 if (!tb)
393 goto fail_unlock;
394tb_found:
395 if (!hlist_empty(&tb->owners)) {
396 if (sk->sk_reuse == SK_FORCE_REUSE)
397 goto success;
398
399 if ((tb->fastreuse > 0 && reuse) ||
400 sk_reuseport_match(tb, sk))
401 goto success;
402 if (inet_csk_bind_conflict(sk, tb, true, true))
403 goto fail_unlock;
404 }
405success:
406 inet_csk_update_fastreuse(tb, sk);
407
408 if (!inet_csk(sk)->icsk_bind_hash)
409 inet_bind_hash(sk, tb, port);
410 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
411 ret = 0;
412
413fail_unlock:
414 spin_unlock_bh(&head->lock);
415 return ret;
416}
417EXPORT_SYMBOL_GPL(inet_csk_get_port);
418
419/*
420 * Wait for an incoming connection, avoid race conditions. This must be called
421 * with the socket locked.
422 */
423static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
424{
425 struct inet_connection_sock *icsk = inet_csk(sk);
426 DEFINE_WAIT(wait);
427 int err;
428
429 /*
430 * True wake-one mechanism for incoming connections: only
431 * one process gets woken up, not the 'whole herd'.
432 * Since we do not 'race & poll' for established sockets
433 * anymore, the common case will execute the loop only once.
434 *
435 * Subtle issue: "add_wait_queue_exclusive()" will be added
436 * after any current non-exclusive waiters, and we know that
437 * it will always _stay_ after any new non-exclusive waiters
438 * because all non-exclusive waiters are added at the
439 * beginning of the wait-queue. As such, it's ok to "drop"
440 * our exclusiveness temporarily when we get woken up without
441 * having to remove and re-insert us on the wait queue.
442 */
443 for (;;) {
444 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
445 TASK_INTERRUPTIBLE);
446 release_sock(sk);
447 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
448 timeo = schedule_timeout(timeo);
449 sched_annotate_sleep();
450 lock_sock(sk);
451 err = 0;
452 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
453 break;
454 err = -EINVAL;
455 if (sk->sk_state != TCP_LISTEN)
456 break;
457 err = sock_intr_errno(timeo);
458 if (signal_pending(current))
459 break;
460 err = -EAGAIN;
461 if (!timeo)
462 break;
463 }
464 finish_wait(sk_sleep(sk), &wait);
465 return err;
466}
467
468/*
469 * This will accept the next outstanding connection.
470 */
471struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
472{
473 struct inet_connection_sock *icsk = inet_csk(sk);
474 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
475 struct request_sock *req;
476 struct sock *newsk;
477 int error;
478
479 lock_sock(sk);
480
481 /* We need to make sure that this socket is listening,
482 * and that it has something pending.
483 */
484 error = -EINVAL;
485 if (sk->sk_state != TCP_LISTEN)
486 goto out_err;
487
488 /* Find already established connection */
489 if (reqsk_queue_empty(queue)) {
490 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
491
492 /* If this is a non blocking socket don't sleep */
493 error = -EAGAIN;
494 if (!timeo)
495 goto out_err;
496
497 error = inet_csk_wait_for_connect(sk, timeo);
498 if (error)
499 goto out_err;
500 }
501 req = reqsk_queue_remove(queue, sk);
502 newsk = req->sk;
503
504 if (sk->sk_protocol == IPPROTO_TCP &&
505 tcp_rsk(req)->tfo_listener) {
506 spin_lock_bh(&queue->fastopenq.lock);
507 if (tcp_rsk(req)->tfo_listener) {
508 /* We are still waiting for the final ACK from 3WHS
509 * so can't free req now. Instead, we set req->sk to
510 * NULL to signify that the child socket is taken
511 * so reqsk_fastopen_remove() will free the req
512 * when 3WHS finishes (or is aborted).
513 */
514 req->sk = NULL;
515 req = NULL;
516 }
517 spin_unlock_bh(&queue->fastopenq.lock);
518 }
519
520out:
521 release_sock(sk);
522 if (newsk && mem_cgroup_sockets_enabled) {
523 int amt;
524
525 /* atomically get the memory usage, set and charge the
526 * newsk->sk_memcg.
527 */
528 lock_sock(newsk);
529
530 /* The socket has not been accepted yet, no need to look at
531 * newsk->sk_wmem_queued.
532 */
533 amt = sk_mem_pages(newsk->sk_forward_alloc +
534 atomic_read(&newsk->sk_rmem_alloc));
535 mem_cgroup_sk_alloc(newsk);
536 if (newsk->sk_memcg && amt)
537 mem_cgroup_charge_skmem(newsk->sk_memcg, amt);
538
539 release_sock(newsk);
540 }
541 if (req)
542 reqsk_put(req);
543 return newsk;
544out_err:
545 newsk = NULL;
546 req = NULL;
547 *err = error;
548 goto out;
549}
550EXPORT_SYMBOL(inet_csk_accept);
551
552/*
553 * Using different timers for retransmit, delayed acks and probes
554 * We may wish use just one timer maintaining a list of expire jiffies
555 * to optimize.
556 */
557void inet_csk_init_xmit_timers(struct sock *sk,
558 void (*retransmit_handler)(struct timer_list *t),
559 void (*delack_handler)(struct timer_list *t),
560 void (*keepalive_handler)(struct timer_list *t))
561{
562 struct inet_connection_sock *icsk = inet_csk(sk);
563
564 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
565 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
566 timer_setup(&sk->sk_timer, keepalive_handler, 0);
567 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
568}
569EXPORT_SYMBOL(inet_csk_init_xmit_timers);
570
571void inet_csk_clear_xmit_timers(struct sock *sk)
572{
573 struct inet_connection_sock *icsk = inet_csk(sk);
574
575 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
576
577 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
578 sk_stop_timer(sk, &icsk->icsk_delack_timer);
579 sk_stop_timer(sk, &sk->sk_timer);
580}
581EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
582
583void inet_csk_delete_keepalive_timer(struct sock *sk)
584{
585 sk_stop_timer(sk, &sk->sk_timer);
586}
587EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
588
589void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
590{
591 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
592}
593EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
594
595struct dst_entry *inet_csk_route_req(const struct sock *sk,
596 struct flowi4 *fl4,
597 const struct request_sock *req)
598{
599 const struct inet_request_sock *ireq = inet_rsk(req);
600 struct net *net = read_pnet(&ireq->ireq_net);
601 struct ip_options_rcu *opt;
602 struct rtable *rt;
603
604 rcu_read_lock();
605 opt = rcu_dereference(ireq->ireq_opt);
606
607 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
608 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
609 sk->sk_protocol, inet_sk_flowi_flags(sk),
610 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
611 ireq->ir_loc_addr, ireq->ir_rmt_port,
612 htons(ireq->ir_num), sk->sk_uid);
613 security_req_classify_flow(req, flowi4_to_flowi_common(fl4));
614 rt = ip_route_output_flow(net, fl4, sk);
615 if (IS_ERR(rt))
616 goto no_route;
617 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
618 goto route_err;
619 rcu_read_unlock();
620 return &rt->dst;
621
622route_err:
623 ip_rt_put(rt);
624no_route:
625 rcu_read_unlock();
626 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
627 return NULL;
628}
629EXPORT_SYMBOL_GPL(inet_csk_route_req);
630
631struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
632 struct sock *newsk,
633 const struct request_sock *req)
634{
635 const struct inet_request_sock *ireq = inet_rsk(req);
636 struct net *net = read_pnet(&ireq->ireq_net);
637 struct inet_sock *newinet = inet_sk(newsk);
638 struct ip_options_rcu *opt;
639 struct flowi4 *fl4;
640 struct rtable *rt;
641
642 opt = rcu_dereference(ireq->ireq_opt);
643 fl4 = &newinet->cork.fl.u.ip4;
644
645 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
646 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
647 sk->sk_protocol, inet_sk_flowi_flags(sk),
648 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
649 ireq->ir_loc_addr, ireq->ir_rmt_port,
650 htons(ireq->ir_num), sk->sk_uid);
651 security_req_classify_flow(req, flowi4_to_flowi_common(fl4));
652 rt = ip_route_output_flow(net, fl4, sk);
653 if (IS_ERR(rt))
654 goto no_route;
655 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
656 goto route_err;
657 return &rt->dst;
658
659route_err:
660 ip_rt_put(rt);
661no_route:
662 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
663 return NULL;
664}
665EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
666
667/* Decide when to expire the request and when to resend SYN-ACK */
668static void syn_ack_recalc(struct request_sock *req,
669 const int max_syn_ack_retries,
670 const u8 rskq_defer_accept,
671 int *expire, int *resend)
672{
673 if (!rskq_defer_accept) {
674 *expire = req->num_timeout >= max_syn_ack_retries;
675 *resend = 1;
676 return;
677 }
678 *expire = req->num_timeout >= max_syn_ack_retries &&
679 (!inet_rsk(req)->acked || req->num_timeout >= rskq_defer_accept);
680 /* Do not resend while waiting for data after ACK,
681 * start to resend on end of deferring period to give
682 * last chance for data or ACK to create established socket.
683 */
684 *resend = !inet_rsk(req)->acked ||
685 req->num_timeout >= rskq_defer_accept - 1;
686}
687
688int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
689{
690 int err = req->rsk_ops->rtx_syn_ack(parent, req);
691
692 if (!err)
693 req->num_retrans++;
694 return err;
695}
696EXPORT_SYMBOL(inet_rtx_syn_ack);
697
698static struct request_sock *inet_reqsk_clone(struct request_sock *req,
699 struct sock *sk)
700{
701 struct sock *req_sk, *nreq_sk;
702 struct request_sock *nreq;
703
704 nreq = kmem_cache_alloc(req->rsk_ops->slab, GFP_ATOMIC | __GFP_NOWARN);
705 if (!nreq) {
706 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
707
708 /* paired with refcount_inc_not_zero() in reuseport_migrate_sock() */
709 sock_put(sk);
710 return NULL;
711 }
712
713 req_sk = req_to_sk(req);
714 nreq_sk = req_to_sk(nreq);
715
716 memcpy(nreq_sk, req_sk,
717 offsetof(struct sock, sk_dontcopy_begin));
718 memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end,
719 req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end));
720
721 sk_node_init(&nreq_sk->sk_node);
722 nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping;
723#ifdef CONFIG_XPS
724 nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping;
725#endif
726 nreq_sk->sk_incoming_cpu = req_sk->sk_incoming_cpu;
727
728 nreq->rsk_listener = sk;
729
730 /* We need not acquire fastopenq->lock
731 * because the child socket is locked in inet_csk_listen_stop().
732 */
733 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(nreq)->tfo_listener)
734 rcu_assign_pointer(tcp_sk(nreq->sk)->fastopen_rsk, nreq);
735
736 return nreq;
737}
738
739static void reqsk_queue_migrated(struct request_sock_queue *queue,
740 const struct request_sock *req)
741{
742 if (req->num_timeout == 0)
743 atomic_inc(&queue->young);
744 atomic_inc(&queue->qlen);
745}
746
747static void reqsk_migrate_reset(struct request_sock *req)
748{
749 req->saved_syn = NULL;
750#if IS_ENABLED(CONFIG_IPV6)
751 inet_rsk(req)->ipv6_opt = NULL;
752 inet_rsk(req)->pktopts = NULL;
753#else
754 inet_rsk(req)->ireq_opt = NULL;
755#endif
756}
757
758/* return true if req was found in the ehash table */
759static bool reqsk_queue_unlink(struct request_sock *req)
760{
761 struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo;
762 bool found = false;
763
764 if (sk_hashed(req_to_sk(req))) {
765 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
766
767 spin_lock(lock);
768 found = __sk_nulls_del_node_init_rcu(req_to_sk(req));
769 spin_unlock(lock);
770 }
771 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
772 reqsk_put(req);
773 return found;
774}
775
776bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
777{
778 bool unlinked = reqsk_queue_unlink(req);
779
780 if (unlinked) {
781 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
782 reqsk_put(req);
783 }
784 return unlinked;
785}
786EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
787
788void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
789{
790 inet_csk_reqsk_queue_drop(sk, req);
791 reqsk_put(req);
792}
793EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
794
795static void reqsk_timer_handler(struct timer_list *t)
796{
797 struct request_sock *req = from_timer(req, t, rsk_timer);
798 struct request_sock *nreq = NULL, *oreq = req;
799 struct sock *sk_listener = req->rsk_listener;
800 struct inet_connection_sock *icsk;
801 struct request_sock_queue *queue;
802 struct net *net;
803 int max_syn_ack_retries, qlen, expire = 0, resend = 0;
804
805 if (inet_sk_state_load(sk_listener) != TCP_LISTEN) {
806 struct sock *nsk;
807
808 nsk = reuseport_migrate_sock(sk_listener, req_to_sk(req), NULL);
809 if (!nsk)
810 goto drop;
811
812 nreq = inet_reqsk_clone(req, nsk);
813 if (!nreq)
814 goto drop;
815
816 /* The new timer for the cloned req can decrease the 2
817 * by calling inet_csk_reqsk_queue_drop_and_put(), so
818 * hold another count to prevent use-after-free and
819 * call reqsk_put() just before return.
820 */
821 refcount_set(&nreq->rsk_refcnt, 2 + 1);
822 timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
823 reqsk_queue_migrated(&inet_csk(nsk)->icsk_accept_queue, req);
824
825 req = nreq;
826 sk_listener = nsk;
827 }
828
829 icsk = inet_csk(sk_listener);
830 net = sock_net(sk_listener);
831 max_syn_ack_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries;
832 /* Normally all the openreqs are young and become mature
833 * (i.e. converted to established socket) for first timeout.
834 * If synack was not acknowledged for 1 second, it means
835 * one of the following things: synack was lost, ack was lost,
836 * rtt is high or nobody planned to ack (i.e. synflood).
837 * When server is a bit loaded, queue is populated with old
838 * open requests, reducing effective size of queue.
839 * When server is well loaded, queue size reduces to zero
840 * after several minutes of work. It is not synflood,
841 * it is normal operation. The solution is pruning
842 * too old entries overriding normal timeout, when
843 * situation becomes dangerous.
844 *
845 * Essentially, we reserve half of room for young
846 * embrions; and abort old ones without pity, if old
847 * ones are about to clog our table.
848 */
849 queue = &icsk->icsk_accept_queue;
850 qlen = reqsk_queue_len(queue);
851 if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {
852 int young = reqsk_queue_len_young(queue) << 1;
853
854 while (max_syn_ack_retries > 2) {
855 if (qlen < young)
856 break;
857 max_syn_ack_retries--;
858 young <<= 1;
859 }
860 }
861 syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept),
862 &expire, &resend);
863 req->rsk_ops->syn_ack_timeout(req);
864 if (!expire &&
865 (!resend ||
866 !inet_rtx_syn_ack(sk_listener, req) ||
867 inet_rsk(req)->acked)) {
868 unsigned long timeo;
869
870 if (req->num_timeout++ == 0)
871 atomic_dec(&queue->young);
872 timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
873 mod_timer(&req->rsk_timer, jiffies + timeo);
874
875 if (!nreq)
876 return;
877
878 if (!inet_ehash_insert(req_to_sk(nreq), req_to_sk(oreq), NULL)) {
879 /* delete timer */
880 inet_csk_reqsk_queue_drop(sk_listener, nreq);
881 goto no_ownership;
882 }
883
884 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQSUCCESS);
885 reqsk_migrate_reset(oreq);
886 reqsk_queue_removed(&inet_csk(oreq->rsk_listener)->icsk_accept_queue, oreq);
887 reqsk_put(oreq);
888
889 reqsk_put(nreq);
890 return;
891 }
892
893 /* Even if we can clone the req, we may need not retransmit any more
894 * SYN+ACKs (nreq->num_timeout > max_syn_ack_retries, etc), or another
895 * CPU may win the "own_req" race so that inet_ehash_insert() fails.
896 */
897 if (nreq) {
898 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQFAILURE);
899no_ownership:
900 reqsk_migrate_reset(nreq);
901 reqsk_queue_removed(queue, nreq);
902 __reqsk_free(nreq);
903 }
904
905drop:
906 inet_csk_reqsk_queue_drop_and_put(oreq->rsk_listener, oreq);
907}
908
909static void reqsk_queue_hash_req(struct request_sock *req,
910 unsigned long timeout)
911{
912 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
913 mod_timer(&req->rsk_timer, jiffies + timeout);
914
915 inet_ehash_insert(req_to_sk(req), NULL, NULL);
916 /* before letting lookups find us, make sure all req fields
917 * are committed to memory and refcnt initialized.
918 */
919 smp_wmb();
920 refcount_set(&req->rsk_refcnt, 2 + 1);
921}
922
923void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
924 unsigned long timeout)
925{
926 reqsk_queue_hash_req(req, timeout);
927 inet_csk_reqsk_queue_added(sk);
928}
929EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
930
931static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk,
932 const gfp_t priority)
933{
934 struct inet_connection_sock *icsk = inet_csk(newsk);
935
936 if (!icsk->icsk_ulp_ops)
937 return;
938
939 if (icsk->icsk_ulp_ops->clone)
940 icsk->icsk_ulp_ops->clone(req, newsk, priority);
941}
942
943/**
944 * inet_csk_clone_lock - clone an inet socket, and lock its clone
945 * @sk: the socket to clone
946 * @req: request_sock
947 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
948 *
949 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
950 */
951struct sock *inet_csk_clone_lock(const struct sock *sk,
952 const struct request_sock *req,
953 const gfp_t priority)
954{
955 struct sock *newsk = sk_clone_lock(sk, priority);
956
957 if (newsk) {
958 struct inet_connection_sock *newicsk = inet_csk(newsk);
959
960 inet_sk_set_state(newsk, TCP_SYN_RECV);
961 newicsk->icsk_bind_hash = NULL;
962
963 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
964 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
965 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
966
967 /* listeners have SOCK_RCU_FREE, not the children */
968 sock_reset_flag(newsk, SOCK_RCU_FREE);
969
970 inet_sk(newsk)->mc_list = NULL;
971
972 newsk->sk_mark = inet_rsk(req)->ir_mark;
973 atomic64_set(&newsk->sk_cookie,
974 atomic64_read(&inet_rsk(req)->ir_cookie));
975
976 newicsk->icsk_retransmits = 0;
977 newicsk->icsk_backoff = 0;
978 newicsk->icsk_probes_out = 0;
979 newicsk->icsk_probes_tstamp = 0;
980
981 /* Deinitialize accept_queue to trap illegal accesses. */
982 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
983
984 inet_clone_ulp(req, newsk, priority);
985
986 security_inet_csk_clone(newsk, req);
987 }
988 return newsk;
989}
990EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
991
992/*
993 * At this point, there should be no process reference to this
994 * socket, and thus no user references at all. Therefore we
995 * can assume the socket waitqueue is inactive and nobody will
996 * try to jump onto it.
997 */
998void inet_csk_destroy_sock(struct sock *sk)
999{
1000 WARN_ON(sk->sk_state != TCP_CLOSE);
1001 WARN_ON(!sock_flag(sk, SOCK_DEAD));
1002
1003 /* It cannot be in hash table! */
1004 WARN_ON(!sk_unhashed(sk));
1005
1006 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
1007 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
1008
1009 sk->sk_prot->destroy(sk);
1010
1011 sk_stream_kill_queues(sk);
1012
1013 xfrm_sk_free_policy(sk);
1014
1015 sk_refcnt_debug_release(sk);
1016
1017 percpu_counter_dec(sk->sk_prot->orphan_count);
1018
1019 sock_put(sk);
1020}
1021EXPORT_SYMBOL(inet_csk_destroy_sock);
1022
1023/* This function allows to force a closure of a socket after the call to
1024 * tcp/dccp_create_openreq_child().
1025 */
1026void inet_csk_prepare_forced_close(struct sock *sk)
1027 __releases(&sk->sk_lock.slock)
1028{
1029 /* sk_clone_lock locked the socket and set refcnt to 2 */
1030 bh_unlock_sock(sk);
1031 sock_put(sk);
1032 inet_csk_prepare_for_destroy_sock(sk);
1033 inet_sk(sk)->inet_num = 0;
1034}
1035EXPORT_SYMBOL(inet_csk_prepare_forced_close);
1036
1037int inet_csk_listen_start(struct sock *sk, int backlog)
1038{
1039 struct inet_connection_sock *icsk = inet_csk(sk);
1040 struct inet_sock *inet = inet_sk(sk);
1041 int err = -EADDRINUSE;
1042
1043 reqsk_queue_alloc(&icsk->icsk_accept_queue);
1044
1045 sk->sk_ack_backlog = 0;
1046 inet_csk_delack_init(sk);
1047
1048 /* There is race window here: we announce ourselves listening,
1049 * but this transition is still not validated by get_port().
1050 * It is OK, because this socket enters to hash table only
1051 * after validation is complete.
1052 */
1053 inet_sk_state_store(sk, TCP_LISTEN);
1054 if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
1055 inet->inet_sport = htons(inet->inet_num);
1056
1057 sk_dst_reset(sk);
1058 err = sk->sk_prot->hash(sk);
1059
1060 if (likely(!err))
1061 return 0;
1062 }
1063
1064 inet_sk_set_state(sk, TCP_CLOSE);
1065 return err;
1066}
1067EXPORT_SYMBOL_GPL(inet_csk_listen_start);
1068
1069static void inet_child_forget(struct sock *sk, struct request_sock *req,
1070 struct sock *child)
1071{
1072 sk->sk_prot->disconnect(child, O_NONBLOCK);
1073
1074 sock_orphan(child);
1075
1076 percpu_counter_inc(sk->sk_prot->orphan_count);
1077
1078 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
1079 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req);
1080 BUG_ON(sk != req->rsk_listener);
1081
1082 /* Paranoid, to prevent race condition if
1083 * an inbound pkt destined for child is
1084 * blocked by sock lock in tcp_v4_rcv().
1085 * Also to satisfy an assertion in
1086 * tcp_v4_destroy_sock().
1087 */
1088 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL);
1089 }
1090 inet_csk_destroy_sock(child);
1091}
1092
1093struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
1094 struct request_sock *req,
1095 struct sock *child)
1096{
1097 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
1098
1099 spin_lock(&queue->rskq_lock);
1100 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1101 inet_child_forget(sk, req, child);
1102 child = NULL;
1103 } else {
1104 req->sk = child;
1105 req->dl_next = NULL;
1106 if (queue->rskq_accept_head == NULL)
1107 WRITE_ONCE(queue->rskq_accept_head, req);
1108 else
1109 queue->rskq_accept_tail->dl_next = req;
1110 queue->rskq_accept_tail = req;
1111 sk_acceptq_added(sk);
1112 }
1113 spin_unlock(&queue->rskq_lock);
1114 return child;
1115}
1116EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
1117
1118struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
1119 struct request_sock *req, bool own_req)
1120{
1121 if (own_req) {
1122 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
1123 reqsk_queue_removed(&inet_csk(req->rsk_listener)->icsk_accept_queue, req);
1124
1125 if (sk != req->rsk_listener) {
1126 /* another listening sk has been selected,
1127 * migrate the req to it.
1128 */
1129 struct request_sock *nreq;
1130
1131 /* hold a refcnt for the nreq->rsk_listener
1132 * which is assigned in inet_reqsk_clone()
1133 */
1134 sock_hold(sk);
1135 nreq = inet_reqsk_clone(req, sk);
1136 if (!nreq) {
1137 inet_child_forget(sk, req, child);
1138 goto child_put;
1139 }
1140
1141 refcount_set(&nreq->rsk_refcnt, 1);
1142 if (inet_csk_reqsk_queue_add(sk, nreq, child)) {
1143 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQSUCCESS);
1144 reqsk_migrate_reset(req);
1145 reqsk_put(req);
1146 return child;
1147 }
1148
1149 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
1150 reqsk_migrate_reset(nreq);
1151 __reqsk_free(nreq);
1152 } else if (inet_csk_reqsk_queue_add(sk, req, child)) {
1153 return child;
1154 }
1155 }
1156 /* Too bad, another child took ownership of the request, undo. */
1157child_put:
1158 bh_unlock_sock(child);
1159 sock_put(child);
1160 return NULL;
1161}
1162EXPORT_SYMBOL(inet_csk_complete_hashdance);
1163
1164/*
1165 * This routine closes sockets which have been at least partially
1166 * opened, but not yet accepted.
1167 */
1168void inet_csk_listen_stop(struct sock *sk)
1169{
1170 struct inet_connection_sock *icsk = inet_csk(sk);
1171 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
1172 struct request_sock *next, *req;
1173
1174 /* Following specs, it would be better either to send FIN
1175 * (and enter FIN-WAIT-1, it is normal close)
1176 * or to send active reset (abort).
1177 * Certainly, it is pretty dangerous while synflood, but it is
1178 * bad justification for our negligence 8)
1179 * To be honest, we are not able to make either
1180 * of the variants now. --ANK
1181 */
1182 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
1183 struct sock *child = req->sk, *nsk;
1184 struct request_sock *nreq;
1185
1186 local_bh_disable();
1187 bh_lock_sock(child);
1188 WARN_ON(sock_owned_by_user(child));
1189 sock_hold(child);
1190
1191 nsk = reuseport_migrate_sock(sk, child, NULL);
1192 if (nsk) {
1193 nreq = inet_reqsk_clone(req, nsk);
1194 if (nreq) {
1195 refcount_set(&nreq->rsk_refcnt, 1);
1196
1197 if (inet_csk_reqsk_queue_add(nsk, nreq, child)) {
1198 __NET_INC_STATS(sock_net(nsk),
1199 LINUX_MIB_TCPMIGRATEREQSUCCESS);
1200 reqsk_migrate_reset(req);
1201 } else {
1202 __NET_INC_STATS(sock_net(nsk),
1203 LINUX_MIB_TCPMIGRATEREQFAILURE);
1204 reqsk_migrate_reset(nreq);
1205 __reqsk_free(nreq);
1206 }
1207
1208 /* inet_csk_reqsk_queue_add() has already
1209 * called inet_child_forget() on failure case.
1210 */
1211 goto skip_child_forget;
1212 }
1213 }
1214
1215 inet_child_forget(sk, req, child);
1216skip_child_forget:
1217 reqsk_put(req);
1218 bh_unlock_sock(child);
1219 local_bh_enable();
1220 sock_put(child);
1221
1222 cond_resched();
1223 }
1224 if (queue->fastopenq.rskq_rst_head) {
1225 /* Free all the reqs queued in rskq_rst_head. */
1226 spin_lock_bh(&queue->fastopenq.lock);
1227 req = queue->fastopenq.rskq_rst_head;
1228 queue->fastopenq.rskq_rst_head = NULL;
1229 spin_unlock_bh(&queue->fastopenq.lock);
1230 while (req != NULL) {
1231 next = req->dl_next;
1232 reqsk_put(req);
1233 req = next;
1234 }
1235 }
1236 WARN_ON_ONCE(sk->sk_ack_backlog);
1237}
1238EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1239
1240void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1241{
1242 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1243 const struct inet_sock *inet = inet_sk(sk);
1244
1245 sin->sin_family = AF_INET;
1246 sin->sin_addr.s_addr = inet->inet_daddr;
1247 sin->sin_port = inet->inet_dport;
1248}
1249EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1250
1251static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1252{
1253 const struct inet_sock *inet = inet_sk(sk);
1254 const struct ip_options_rcu *inet_opt;
1255 __be32 daddr = inet->inet_daddr;
1256 struct flowi4 *fl4;
1257 struct rtable *rt;
1258
1259 rcu_read_lock();
1260 inet_opt = rcu_dereference(inet->inet_opt);
1261 if (inet_opt && inet_opt->opt.srr)
1262 daddr = inet_opt->opt.faddr;
1263 fl4 = &fl->u.ip4;
1264 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
1265 inet->inet_saddr, inet->inet_dport,
1266 inet->inet_sport, sk->sk_protocol,
1267 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
1268 if (IS_ERR(rt))
1269 rt = NULL;
1270 if (rt)
1271 sk_setup_caps(sk, &rt->dst);
1272 rcu_read_unlock();
1273
1274 return &rt->dst;
1275}
1276
1277struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1278{
1279 struct dst_entry *dst = __sk_dst_check(sk, 0);
1280 struct inet_sock *inet = inet_sk(sk);
1281
1282 if (!dst) {
1283 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1284 if (!dst)
1285 goto out;
1286 }
1287 dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
1288
1289 dst = __sk_dst_check(sk, 0);
1290 if (!dst)
1291 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1292out:
1293 return dst;
1294}
1295EXPORT_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 int inet_csk_bind_conflict(const struct sock *sk,
134 const struct inet_bind_bucket *tb,
135 bool relax, bool reuseport_ok)
136{
137 struct sock *sk2;
138 bool reuse = sk->sk_reuse;
139 bool reuseport = !!sk->sk_reuseport;
140 kuid_t uid = sock_i_uid((struct sock *)sk);
141
142 /*
143 * Unlike other sk lookup places we do not check
144 * for sk_net here, since _all_ the socks listed
145 * in tb->owners list belong to the same net - the
146 * one this bucket belongs to.
147 */
148
149 sk_for_each_bound(sk2, &tb->owners) {
150 if (sk != sk2 &&
151 (!sk->sk_bound_dev_if ||
152 !sk2->sk_bound_dev_if ||
153 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
154 if (reuse && sk2->sk_reuse &&
155 sk2->sk_state != TCP_LISTEN) {
156 if ((!relax ||
157 (!reuseport_ok &&
158 reuseport && sk2->sk_reuseport &&
159 !rcu_access_pointer(sk->sk_reuseport_cb) &&
160 (sk2->sk_state == TCP_TIME_WAIT ||
161 uid_eq(uid, sock_i_uid(sk2))))) &&
162 inet_rcv_saddr_equal(sk, sk2, true))
163 break;
164 } else if (!reuseport_ok ||
165 !reuseport || !sk2->sk_reuseport ||
166 rcu_access_pointer(sk->sk_reuseport_cb) ||
167 (sk2->sk_state != TCP_TIME_WAIT &&
168 !uid_eq(uid, sock_i_uid(sk2)))) {
169 if (inet_rcv_saddr_equal(sk, sk2, true))
170 break;
171 }
172 }
173 }
174 return sk2 != NULL;
175}
176
177/*
178 * Find an open port number for the socket. Returns with the
179 * inet_bind_hashbucket lock held.
180 */
181static struct inet_bind_hashbucket *
182inet_csk_find_open_port(struct sock *sk, struct inet_bind_bucket **tb_ret, int *port_ret)
183{
184 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
185 int port = 0;
186 struct inet_bind_hashbucket *head;
187 struct net *net = sock_net(sk);
188 bool relax = false;
189 int i, low, high, attempt_half;
190 struct inet_bind_bucket *tb;
191 u32 remaining, offset;
192 int l3mdev;
193
194 l3mdev = inet_sk_bound_l3mdev(sk);
195ports_exhausted:
196 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
197other_half_scan:
198 inet_get_local_port_range(net, &low, &high);
199 high++; /* [32768, 60999] -> [32768, 61000[ */
200 if (high - low < 4)
201 attempt_half = 0;
202 if (attempt_half) {
203 int half = low + (((high - low) >> 2) << 1);
204
205 if (attempt_half == 1)
206 high = half;
207 else
208 low = half;
209 }
210 remaining = high - low;
211 if (likely(remaining > 1))
212 remaining &= ~1U;
213
214 offset = prandom_u32() % remaining;
215 /* __inet_hash_connect() favors ports having @low parity
216 * We do the opposite to not pollute connect() users.
217 */
218 offset |= 1U;
219
220other_parity_scan:
221 port = low + offset;
222 for (i = 0; i < remaining; i += 2, port += 2) {
223 if (unlikely(port >= high))
224 port -= remaining;
225 if (inet_is_local_reserved_port(net, port))
226 continue;
227 head = &hinfo->bhash[inet_bhashfn(net, port,
228 hinfo->bhash_size)];
229 spin_lock_bh(&head->lock);
230 inet_bind_bucket_for_each(tb, &head->chain)
231 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
232 tb->port == port) {
233 if (!inet_csk_bind_conflict(sk, tb, relax, false))
234 goto success;
235 goto next_port;
236 }
237 tb = NULL;
238 goto success;
239next_port:
240 spin_unlock_bh(&head->lock);
241 cond_resched();
242 }
243
244 offset--;
245 if (!(offset & 1))
246 goto other_parity_scan;
247
248 if (attempt_half == 1) {
249 /* OK we now try the upper half of the range */
250 attempt_half = 2;
251 goto other_half_scan;
252 }
253
254 if (net->ipv4.sysctl_ip_autobind_reuse && !relax) {
255 /* We still have a chance to connect to different destinations */
256 relax = true;
257 goto ports_exhausted;
258 }
259 return NULL;
260success:
261 *port_ret = port;
262 *tb_ret = tb;
263 return head;
264}
265
266static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
267 struct sock *sk)
268{
269 kuid_t uid = sock_i_uid(sk);
270
271 if (tb->fastreuseport <= 0)
272 return 0;
273 if (!sk->sk_reuseport)
274 return 0;
275 if (rcu_access_pointer(sk->sk_reuseport_cb))
276 return 0;
277 if (!uid_eq(tb->fastuid, uid))
278 return 0;
279 /* We only need to check the rcv_saddr if this tb was once marked
280 * without fastreuseport and then was reset, as we can only know that
281 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
282 * owners list.
283 */
284 if (tb->fastreuseport == FASTREUSEPORT_ANY)
285 return 1;
286#if IS_ENABLED(CONFIG_IPV6)
287 if (tb->fast_sk_family == AF_INET6)
288 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
289 inet6_rcv_saddr(sk),
290 tb->fast_rcv_saddr,
291 sk->sk_rcv_saddr,
292 tb->fast_ipv6_only,
293 ipv6_only_sock(sk), true, false);
294#endif
295 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
296 ipv6_only_sock(sk), true, false);
297}
298
299void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
300 struct sock *sk)
301{
302 kuid_t uid = sock_i_uid(sk);
303 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
304
305 if (hlist_empty(&tb->owners)) {
306 tb->fastreuse = reuse;
307 if (sk->sk_reuseport) {
308 tb->fastreuseport = FASTREUSEPORT_ANY;
309 tb->fastuid = uid;
310 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
311 tb->fast_ipv6_only = ipv6_only_sock(sk);
312 tb->fast_sk_family = sk->sk_family;
313#if IS_ENABLED(CONFIG_IPV6)
314 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
315#endif
316 } else {
317 tb->fastreuseport = 0;
318 }
319 } else {
320 if (!reuse)
321 tb->fastreuse = 0;
322 if (sk->sk_reuseport) {
323 /* We didn't match or we don't have fastreuseport set on
324 * the tb, but we have sk_reuseport set on this socket
325 * and we know that there are no bind conflicts with
326 * this socket in this tb, so reset our tb's reuseport
327 * settings so that any subsequent sockets that match
328 * our current socket will be put on the fast path.
329 *
330 * If we reset we need to set FASTREUSEPORT_STRICT so we
331 * do extra checking for all subsequent sk_reuseport
332 * socks.
333 */
334 if (!sk_reuseport_match(tb, sk)) {
335 tb->fastreuseport = FASTREUSEPORT_STRICT;
336 tb->fastuid = uid;
337 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
338 tb->fast_ipv6_only = ipv6_only_sock(sk);
339 tb->fast_sk_family = sk->sk_family;
340#if IS_ENABLED(CONFIG_IPV6)
341 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
342#endif
343 }
344 } else {
345 tb->fastreuseport = 0;
346 }
347 }
348}
349
350/* Obtain a reference to a local port for the given sock,
351 * if snum is zero it means select any available local port.
352 * We try to allocate an odd port (and leave even ports for connect())
353 */
354int inet_csk_get_port(struct sock *sk, unsigned short snum)
355{
356 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
357 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
358 int ret = 1, port = snum;
359 struct inet_bind_hashbucket *head;
360 struct net *net = sock_net(sk);
361 struct inet_bind_bucket *tb = NULL;
362 int l3mdev;
363
364 l3mdev = inet_sk_bound_l3mdev(sk);
365
366 if (!port) {
367 head = inet_csk_find_open_port(sk, &tb, &port);
368 if (!head)
369 return ret;
370 if (!tb)
371 goto tb_not_found;
372 goto success;
373 }
374 head = &hinfo->bhash[inet_bhashfn(net, port,
375 hinfo->bhash_size)];
376 spin_lock_bh(&head->lock);
377 inet_bind_bucket_for_each(tb, &head->chain)
378 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
379 tb->port == port)
380 goto tb_found;
381tb_not_found:
382 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
383 net, head, port, l3mdev);
384 if (!tb)
385 goto fail_unlock;
386tb_found:
387 if (!hlist_empty(&tb->owners)) {
388 if (sk->sk_reuse == SK_FORCE_REUSE)
389 goto success;
390
391 if ((tb->fastreuse > 0 && reuse) ||
392 sk_reuseport_match(tb, sk))
393 goto success;
394 if (inet_csk_bind_conflict(sk, tb, true, true))
395 goto fail_unlock;
396 }
397success:
398 inet_csk_update_fastreuse(tb, sk);
399
400 if (!inet_csk(sk)->icsk_bind_hash)
401 inet_bind_hash(sk, tb, port);
402 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
403 ret = 0;
404
405fail_unlock:
406 spin_unlock_bh(&head->lock);
407 return ret;
408}
409EXPORT_SYMBOL_GPL(inet_csk_get_port);
410
411/*
412 * Wait for an incoming connection, avoid race conditions. This must be called
413 * with the socket locked.
414 */
415static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
416{
417 struct inet_connection_sock *icsk = inet_csk(sk);
418 DEFINE_WAIT(wait);
419 int err;
420
421 /*
422 * True wake-one mechanism for incoming connections: only
423 * one process gets woken up, not the 'whole herd'.
424 * Since we do not 'race & poll' for established sockets
425 * anymore, the common case will execute the loop only once.
426 *
427 * Subtle issue: "add_wait_queue_exclusive()" will be added
428 * after any current non-exclusive waiters, and we know that
429 * it will always _stay_ after any new non-exclusive waiters
430 * because all non-exclusive waiters are added at the
431 * beginning of the wait-queue. As such, it's ok to "drop"
432 * our exclusiveness temporarily when we get woken up without
433 * having to remove and re-insert us on the wait queue.
434 */
435 for (;;) {
436 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
437 TASK_INTERRUPTIBLE);
438 release_sock(sk);
439 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
440 timeo = schedule_timeout(timeo);
441 sched_annotate_sleep();
442 lock_sock(sk);
443 err = 0;
444 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
445 break;
446 err = -EINVAL;
447 if (sk->sk_state != TCP_LISTEN)
448 break;
449 err = sock_intr_errno(timeo);
450 if (signal_pending(current))
451 break;
452 err = -EAGAIN;
453 if (!timeo)
454 break;
455 }
456 finish_wait(sk_sleep(sk), &wait);
457 return err;
458}
459
460/*
461 * This will accept the next outstanding connection.
462 */
463struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
464{
465 struct inet_connection_sock *icsk = inet_csk(sk);
466 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
467 struct request_sock *req;
468 struct sock *newsk;
469 int error;
470
471 lock_sock(sk);
472
473 /* We need to make sure that this socket is listening,
474 * and that it has something pending.
475 */
476 error = -EINVAL;
477 if (sk->sk_state != TCP_LISTEN)
478 goto out_err;
479
480 /* Find already established connection */
481 if (reqsk_queue_empty(queue)) {
482 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
483
484 /* If this is a non blocking socket don't sleep */
485 error = -EAGAIN;
486 if (!timeo)
487 goto out_err;
488
489 error = inet_csk_wait_for_connect(sk, timeo);
490 if (error)
491 goto out_err;
492 }
493 req = reqsk_queue_remove(queue, sk);
494 newsk = req->sk;
495
496 if (sk->sk_protocol == IPPROTO_TCP &&
497 tcp_rsk(req)->tfo_listener) {
498 spin_lock_bh(&queue->fastopenq.lock);
499 if (tcp_rsk(req)->tfo_listener) {
500 /* We are still waiting for the final ACK from 3WHS
501 * so can't free req now. Instead, we set req->sk to
502 * NULL to signify that the child socket is taken
503 * so reqsk_fastopen_remove() will free the req
504 * when 3WHS finishes (or is aborted).
505 */
506 req->sk = NULL;
507 req = NULL;
508 }
509 spin_unlock_bh(&queue->fastopenq.lock);
510 }
511
512out:
513 release_sock(sk);
514 if (newsk && mem_cgroup_sockets_enabled) {
515 int amt;
516
517 /* atomically get the memory usage, set and charge the
518 * newsk->sk_memcg.
519 */
520 lock_sock(newsk);
521
522 /* The socket has not been accepted yet, no need to look at
523 * newsk->sk_wmem_queued.
524 */
525 amt = sk_mem_pages(newsk->sk_forward_alloc +
526 atomic_read(&newsk->sk_rmem_alloc));
527 mem_cgroup_sk_alloc(newsk);
528 if (newsk->sk_memcg && amt)
529 mem_cgroup_charge_skmem(newsk->sk_memcg, amt);
530
531 release_sock(newsk);
532 }
533 if (req)
534 reqsk_put(req);
535 return newsk;
536out_err:
537 newsk = NULL;
538 req = NULL;
539 *err = error;
540 goto out;
541}
542EXPORT_SYMBOL(inet_csk_accept);
543
544/*
545 * Using different timers for retransmit, delayed acks and probes
546 * We may wish use just one timer maintaining a list of expire jiffies
547 * to optimize.
548 */
549void inet_csk_init_xmit_timers(struct sock *sk,
550 void (*retransmit_handler)(struct timer_list *t),
551 void (*delack_handler)(struct timer_list *t),
552 void (*keepalive_handler)(struct timer_list *t))
553{
554 struct inet_connection_sock *icsk = inet_csk(sk);
555
556 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
557 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
558 timer_setup(&sk->sk_timer, keepalive_handler, 0);
559 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
560}
561EXPORT_SYMBOL(inet_csk_init_xmit_timers);
562
563void inet_csk_clear_xmit_timers(struct sock *sk)
564{
565 struct inet_connection_sock *icsk = inet_csk(sk);
566
567 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
568
569 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
570 sk_stop_timer(sk, &icsk->icsk_delack_timer);
571 sk_stop_timer(sk, &sk->sk_timer);
572}
573EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
574
575void inet_csk_delete_keepalive_timer(struct sock *sk)
576{
577 sk_stop_timer(sk, &sk->sk_timer);
578}
579EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
580
581void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
582{
583 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
584}
585EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
586
587struct dst_entry *inet_csk_route_req(const struct sock *sk,
588 struct flowi4 *fl4,
589 const struct request_sock *req)
590{
591 const struct inet_request_sock *ireq = inet_rsk(req);
592 struct net *net = read_pnet(&ireq->ireq_net);
593 struct ip_options_rcu *opt;
594 struct rtable *rt;
595
596 rcu_read_lock();
597 opt = rcu_dereference(ireq->ireq_opt);
598
599 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
600 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
601 sk->sk_protocol, inet_sk_flowi_flags(sk),
602 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
603 ireq->ir_loc_addr, ireq->ir_rmt_port,
604 htons(ireq->ir_num), sk->sk_uid);
605 security_req_classify_flow(req, flowi4_to_flowi(fl4));
606 rt = ip_route_output_flow(net, fl4, sk);
607 if (IS_ERR(rt))
608 goto no_route;
609 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
610 goto route_err;
611 rcu_read_unlock();
612 return &rt->dst;
613
614route_err:
615 ip_rt_put(rt);
616no_route:
617 rcu_read_unlock();
618 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
619 return NULL;
620}
621EXPORT_SYMBOL_GPL(inet_csk_route_req);
622
623struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
624 struct sock *newsk,
625 const struct request_sock *req)
626{
627 const struct inet_request_sock *ireq = inet_rsk(req);
628 struct net *net = read_pnet(&ireq->ireq_net);
629 struct inet_sock *newinet = inet_sk(newsk);
630 struct ip_options_rcu *opt;
631 struct flowi4 *fl4;
632 struct rtable *rt;
633
634 opt = rcu_dereference(ireq->ireq_opt);
635 fl4 = &newinet->cork.fl.u.ip4;
636
637 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
638 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
639 sk->sk_protocol, inet_sk_flowi_flags(sk),
640 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
641 ireq->ir_loc_addr, ireq->ir_rmt_port,
642 htons(ireq->ir_num), sk->sk_uid);
643 security_req_classify_flow(req, flowi4_to_flowi(fl4));
644 rt = ip_route_output_flow(net, fl4, sk);
645 if (IS_ERR(rt))
646 goto no_route;
647 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
648 goto route_err;
649 return &rt->dst;
650
651route_err:
652 ip_rt_put(rt);
653no_route:
654 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
655 return NULL;
656}
657EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
658
659/* Decide when to expire the request and when to resend SYN-ACK */
660static void syn_ack_recalc(struct request_sock *req,
661 const int max_syn_ack_retries,
662 const u8 rskq_defer_accept,
663 int *expire, int *resend)
664{
665 if (!rskq_defer_accept) {
666 *expire = req->num_timeout >= max_syn_ack_retries;
667 *resend = 1;
668 return;
669 }
670 *expire = req->num_timeout >= max_syn_ack_retries &&
671 (!inet_rsk(req)->acked || req->num_timeout >= rskq_defer_accept);
672 /* Do not resend while waiting for data after ACK,
673 * start to resend on end of deferring period to give
674 * last chance for data or ACK to create established socket.
675 */
676 *resend = !inet_rsk(req)->acked ||
677 req->num_timeout >= rskq_defer_accept - 1;
678}
679
680int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
681{
682 int err = req->rsk_ops->rtx_syn_ack(parent, req);
683
684 if (!err)
685 req->num_retrans++;
686 return err;
687}
688EXPORT_SYMBOL(inet_rtx_syn_ack);
689
690/* return true if req was found in the ehash table */
691static bool reqsk_queue_unlink(struct request_sock *req)
692{
693 struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo;
694 bool found = false;
695
696 if (sk_hashed(req_to_sk(req))) {
697 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
698
699 spin_lock(lock);
700 found = __sk_nulls_del_node_init_rcu(req_to_sk(req));
701 spin_unlock(lock);
702 }
703 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
704 reqsk_put(req);
705 return found;
706}
707
708void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
709{
710 if (reqsk_queue_unlink(req)) {
711 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
712 reqsk_put(req);
713 }
714}
715EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
716
717void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
718{
719 inet_csk_reqsk_queue_drop(sk, req);
720 reqsk_put(req);
721}
722EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
723
724static void reqsk_timer_handler(struct timer_list *t)
725{
726 struct request_sock *req = from_timer(req, t, rsk_timer);
727 struct sock *sk_listener = req->rsk_listener;
728 struct net *net = sock_net(sk_listener);
729 struct inet_connection_sock *icsk = inet_csk(sk_listener);
730 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
731 int max_syn_ack_retries, qlen, expire = 0, resend = 0;
732
733 if (inet_sk_state_load(sk_listener) != TCP_LISTEN)
734 goto drop;
735
736 max_syn_ack_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries;
737 /* Normally all the openreqs are young and become mature
738 * (i.e. converted to established socket) for first timeout.
739 * If synack was not acknowledged for 1 second, it means
740 * one of the following things: synack was lost, ack was lost,
741 * rtt is high or nobody planned to ack (i.e. synflood).
742 * When server is a bit loaded, queue is populated with old
743 * open requests, reducing effective size of queue.
744 * When server is well loaded, queue size reduces to zero
745 * after several minutes of work. It is not synflood,
746 * it is normal operation. The solution is pruning
747 * too old entries overriding normal timeout, when
748 * situation becomes dangerous.
749 *
750 * Essentially, we reserve half of room for young
751 * embrions; and abort old ones without pity, if old
752 * ones are about to clog our table.
753 */
754 qlen = reqsk_queue_len(queue);
755 if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {
756 int young = reqsk_queue_len_young(queue) << 1;
757
758 while (max_syn_ack_retries > 2) {
759 if (qlen < young)
760 break;
761 max_syn_ack_retries--;
762 young <<= 1;
763 }
764 }
765 syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept),
766 &expire, &resend);
767 req->rsk_ops->syn_ack_timeout(req);
768 if (!expire &&
769 (!resend ||
770 !inet_rtx_syn_ack(sk_listener, req) ||
771 inet_rsk(req)->acked)) {
772 unsigned long timeo;
773
774 if (req->num_timeout++ == 0)
775 atomic_dec(&queue->young);
776 timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
777 mod_timer(&req->rsk_timer, jiffies + timeo);
778 return;
779 }
780drop:
781 inet_csk_reqsk_queue_drop_and_put(sk_listener, req);
782}
783
784static void reqsk_queue_hash_req(struct request_sock *req,
785 unsigned long timeout)
786{
787 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
788 mod_timer(&req->rsk_timer, jiffies + timeout);
789
790 inet_ehash_insert(req_to_sk(req), NULL);
791 /* before letting lookups find us, make sure all req fields
792 * are committed to memory and refcnt initialized.
793 */
794 smp_wmb();
795 refcount_set(&req->rsk_refcnt, 2 + 1);
796}
797
798void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
799 unsigned long timeout)
800{
801 reqsk_queue_hash_req(req, timeout);
802 inet_csk_reqsk_queue_added(sk);
803}
804EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
805
806static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk,
807 const gfp_t priority)
808{
809 struct inet_connection_sock *icsk = inet_csk(newsk);
810
811 if (!icsk->icsk_ulp_ops)
812 return;
813
814 if (icsk->icsk_ulp_ops->clone)
815 icsk->icsk_ulp_ops->clone(req, newsk, priority);
816}
817
818/**
819 * inet_csk_clone_lock - clone an inet socket, and lock its clone
820 * @sk: the socket to clone
821 * @req: request_sock
822 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
823 *
824 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
825 */
826struct sock *inet_csk_clone_lock(const struct sock *sk,
827 const struct request_sock *req,
828 const gfp_t priority)
829{
830 struct sock *newsk = sk_clone_lock(sk, priority);
831
832 if (newsk) {
833 struct inet_connection_sock *newicsk = inet_csk(newsk);
834
835 inet_sk_set_state(newsk, TCP_SYN_RECV);
836 newicsk->icsk_bind_hash = NULL;
837
838 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
839 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
840 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
841
842 /* listeners have SOCK_RCU_FREE, not the children */
843 sock_reset_flag(newsk, SOCK_RCU_FREE);
844
845 inet_sk(newsk)->mc_list = NULL;
846
847 newsk->sk_mark = inet_rsk(req)->ir_mark;
848 atomic64_set(&newsk->sk_cookie,
849 atomic64_read(&inet_rsk(req)->ir_cookie));
850
851 newicsk->icsk_retransmits = 0;
852 newicsk->icsk_backoff = 0;
853 newicsk->icsk_probes_out = 0;
854
855 /* Deinitialize accept_queue to trap illegal accesses. */
856 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
857
858 inet_clone_ulp(req, newsk, priority);
859
860 security_inet_csk_clone(newsk, req);
861 }
862 return newsk;
863}
864EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
865
866/*
867 * At this point, there should be no process reference to this
868 * socket, and thus no user references at all. Therefore we
869 * can assume the socket waitqueue is inactive and nobody will
870 * try to jump onto it.
871 */
872void inet_csk_destroy_sock(struct sock *sk)
873{
874 WARN_ON(sk->sk_state != TCP_CLOSE);
875 WARN_ON(!sock_flag(sk, SOCK_DEAD));
876
877 /* It cannot be in hash table! */
878 WARN_ON(!sk_unhashed(sk));
879
880 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
881 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
882
883 sk->sk_prot->destroy(sk);
884
885 sk_stream_kill_queues(sk);
886
887 xfrm_sk_free_policy(sk);
888
889 sk_refcnt_debug_release(sk);
890
891 percpu_counter_dec(sk->sk_prot->orphan_count);
892
893 sock_put(sk);
894}
895EXPORT_SYMBOL(inet_csk_destroy_sock);
896
897/* This function allows to force a closure of a socket after the call to
898 * tcp/dccp_create_openreq_child().
899 */
900void inet_csk_prepare_forced_close(struct sock *sk)
901 __releases(&sk->sk_lock.slock)
902{
903 /* sk_clone_lock locked the socket and set refcnt to 2 */
904 bh_unlock_sock(sk);
905 sock_put(sk);
906 inet_csk_prepare_for_destroy_sock(sk);
907 inet_sk(sk)->inet_num = 0;
908}
909EXPORT_SYMBOL(inet_csk_prepare_forced_close);
910
911int inet_csk_listen_start(struct sock *sk, int backlog)
912{
913 struct inet_connection_sock *icsk = inet_csk(sk);
914 struct inet_sock *inet = inet_sk(sk);
915 int err = -EADDRINUSE;
916
917 reqsk_queue_alloc(&icsk->icsk_accept_queue);
918
919 sk->sk_ack_backlog = 0;
920 inet_csk_delack_init(sk);
921
922 /* There is race window here: we announce ourselves listening,
923 * but this transition is still not validated by get_port().
924 * It is OK, because this socket enters to hash table only
925 * after validation is complete.
926 */
927 inet_sk_state_store(sk, TCP_LISTEN);
928 if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
929 inet->inet_sport = htons(inet->inet_num);
930
931 sk_dst_reset(sk);
932 err = sk->sk_prot->hash(sk);
933
934 if (likely(!err))
935 return 0;
936 }
937
938 inet_sk_set_state(sk, TCP_CLOSE);
939 return err;
940}
941EXPORT_SYMBOL_GPL(inet_csk_listen_start);
942
943static void inet_child_forget(struct sock *sk, struct request_sock *req,
944 struct sock *child)
945{
946 sk->sk_prot->disconnect(child, O_NONBLOCK);
947
948 sock_orphan(child);
949
950 percpu_counter_inc(sk->sk_prot->orphan_count);
951
952 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
953 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req);
954 BUG_ON(sk != req->rsk_listener);
955
956 /* Paranoid, to prevent race condition if
957 * an inbound pkt destined for child is
958 * blocked by sock lock in tcp_v4_rcv().
959 * Also to satisfy an assertion in
960 * tcp_v4_destroy_sock().
961 */
962 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL);
963 }
964 inet_csk_destroy_sock(child);
965}
966
967struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
968 struct request_sock *req,
969 struct sock *child)
970{
971 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
972
973 spin_lock(&queue->rskq_lock);
974 if (unlikely(sk->sk_state != TCP_LISTEN)) {
975 inet_child_forget(sk, req, child);
976 child = NULL;
977 } else {
978 req->sk = child;
979 req->dl_next = NULL;
980 if (queue->rskq_accept_head == NULL)
981 WRITE_ONCE(queue->rskq_accept_head, req);
982 else
983 queue->rskq_accept_tail->dl_next = req;
984 queue->rskq_accept_tail = req;
985 sk_acceptq_added(sk);
986 }
987 spin_unlock(&queue->rskq_lock);
988 return child;
989}
990EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
991
992struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
993 struct request_sock *req, bool own_req)
994{
995 if (own_req) {
996 inet_csk_reqsk_queue_drop(sk, req);
997 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
998 if (inet_csk_reqsk_queue_add(sk, req, child))
999 return child;
1000 }
1001 /* Too bad, another child took ownership of the request, undo. */
1002 bh_unlock_sock(child);
1003 sock_put(child);
1004 return NULL;
1005}
1006EXPORT_SYMBOL(inet_csk_complete_hashdance);
1007
1008/*
1009 * This routine closes sockets which have been at least partially
1010 * opened, but not yet accepted.
1011 */
1012void inet_csk_listen_stop(struct sock *sk)
1013{
1014 struct inet_connection_sock *icsk = inet_csk(sk);
1015 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
1016 struct request_sock *next, *req;
1017
1018 /* Following specs, it would be better either to send FIN
1019 * (and enter FIN-WAIT-1, it is normal close)
1020 * or to send active reset (abort).
1021 * Certainly, it is pretty dangerous while synflood, but it is
1022 * bad justification for our negligence 8)
1023 * To be honest, we are not able to make either
1024 * of the variants now. --ANK
1025 */
1026 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
1027 struct sock *child = req->sk;
1028
1029 local_bh_disable();
1030 bh_lock_sock(child);
1031 WARN_ON(sock_owned_by_user(child));
1032 sock_hold(child);
1033
1034 inet_child_forget(sk, req, child);
1035 reqsk_put(req);
1036 bh_unlock_sock(child);
1037 local_bh_enable();
1038 sock_put(child);
1039
1040 cond_resched();
1041 }
1042 if (queue->fastopenq.rskq_rst_head) {
1043 /* Free all the reqs queued in rskq_rst_head. */
1044 spin_lock_bh(&queue->fastopenq.lock);
1045 req = queue->fastopenq.rskq_rst_head;
1046 queue->fastopenq.rskq_rst_head = NULL;
1047 spin_unlock_bh(&queue->fastopenq.lock);
1048 while (req != NULL) {
1049 next = req->dl_next;
1050 reqsk_put(req);
1051 req = next;
1052 }
1053 }
1054 WARN_ON_ONCE(sk->sk_ack_backlog);
1055}
1056EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1057
1058void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1059{
1060 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1061 const struct inet_sock *inet = inet_sk(sk);
1062
1063 sin->sin_family = AF_INET;
1064 sin->sin_addr.s_addr = inet->inet_daddr;
1065 sin->sin_port = inet->inet_dport;
1066}
1067EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1068
1069static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1070{
1071 const struct inet_sock *inet = inet_sk(sk);
1072 const struct ip_options_rcu *inet_opt;
1073 __be32 daddr = inet->inet_daddr;
1074 struct flowi4 *fl4;
1075 struct rtable *rt;
1076
1077 rcu_read_lock();
1078 inet_opt = rcu_dereference(inet->inet_opt);
1079 if (inet_opt && inet_opt->opt.srr)
1080 daddr = inet_opt->opt.faddr;
1081 fl4 = &fl->u.ip4;
1082 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
1083 inet->inet_saddr, inet->inet_dport,
1084 inet->inet_sport, sk->sk_protocol,
1085 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
1086 if (IS_ERR(rt))
1087 rt = NULL;
1088 if (rt)
1089 sk_setup_caps(sk, &rt->dst);
1090 rcu_read_unlock();
1091
1092 return &rt->dst;
1093}
1094
1095struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1096{
1097 struct dst_entry *dst = __sk_dst_check(sk, 0);
1098 struct inet_sock *inet = inet_sk(sk);
1099
1100 if (!dst) {
1101 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1102 if (!dst)
1103 goto out;
1104 }
1105 dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
1106
1107 dst = __sk_dst_check(sk, 0);
1108 if (!dst)
1109 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1110out:
1111 return dst;
1112}
1113EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);