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1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Support for INET connection oriented protocols.
7 *
8 * Authors: See the TCP sources
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or(at your option) any later version.
14 */
15
16#include <linux/module.h>
17#include <linux/jhash.h>
18
19#include <net/inet_connection_sock.h>
20#include <net/inet_hashtables.h>
21#include <net/inet_timewait_sock.h>
22#include <net/ip.h>
23#include <net/route.h>
24#include <net/tcp_states.h>
25#include <net/xfrm.h>
26#include <net/tcp.h>
27#include <net/sock_reuseport.h>
28#include <net/addrconf.h>
29
30#ifdef INET_CSK_DEBUG
31const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
32EXPORT_SYMBOL(inet_csk_timer_bug_msg);
33#endif
34
35#if IS_ENABLED(CONFIG_IPV6)
36/* match_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses if IPv6
37 * only, and any IPv4 addresses if not IPv6 only
38 * match_wildcard == false: addresses must be exactly the same, i.e.
39 * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
40 * and 0.0.0.0 equals to 0.0.0.0 only
41 */
42static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6,
43 const struct in6_addr *sk2_rcv_saddr6,
44 __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
45 bool sk1_ipv6only, bool sk2_ipv6only,
46 bool match_wildcard)
47{
48 int addr_type = ipv6_addr_type(sk1_rcv_saddr6);
49 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
50
51 /* if both are mapped, treat as IPv4 */
52 if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
53 if (!sk2_ipv6only) {
54 if (sk1_rcv_saddr == sk2_rcv_saddr)
55 return true;
56 if (!sk1_rcv_saddr || !sk2_rcv_saddr)
57 return match_wildcard;
58 }
59 return false;
60 }
61
62 if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
63 return true;
64
65 if (addr_type2 == IPV6_ADDR_ANY && match_wildcard &&
66 !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
67 return true;
68
69 if (addr_type == IPV6_ADDR_ANY && match_wildcard &&
70 !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
71 return true;
72
73 if (sk2_rcv_saddr6 &&
74 ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6))
75 return true;
76
77 return false;
78}
79#endif
80
81/* match_wildcard == true: 0.0.0.0 equals to any IPv4 addresses
82 * match_wildcard == false: addresses must be exactly the same, i.e.
83 * 0.0.0.0 only equals to 0.0.0.0
84 */
85static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
86 bool sk2_ipv6only, bool match_wildcard)
87{
88 if (!sk2_ipv6only) {
89 if (sk1_rcv_saddr == sk2_rcv_saddr)
90 return true;
91 if (!sk1_rcv_saddr || !sk2_rcv_saddr)
92 return match_wildcard;
93 }
94 return false;
95}
96
97bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
98 bool match_wildcard)
99{
100#if IS_ENABLED(CONFIG_IPV6)
101 if (sk->sk_family == AF_INET6)
102 return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr,
103 inet6_rcv_saddr(sk2),
104 sk->sk_rcv_saddr,
105 sk2->sk_rcv_saddr,
106 ipv6_only_sock(sk),
107 ipv6_only_sock(sk2),
108 match_wildcard);
109#endif
110 return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr,
111 ipv6_only_sock(sk2), match_wildcard);
112}
113EXPORT_SYMBOL(inet_rcv_saddr_equal);
114
115void inet_get_local_port_range(struct net *net, int *low, int *high)
116{
117 unsigned int seq;
118
119 do {
120 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
121
122 *low = net->ipv4.ip_local_ports.range[0];
123 *high = net->ipv4.ip_local_ports.range[1];
124 } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
125}
126EXPORT_SYMBOL(inet_get_local_port_range);
127
128static int inet_csk_bind_conflict(const struct sock *sk,
129 const struct inet_bind_bucket *tb,
130 bool relax, bool reuseport_ok)
131{
132 struct sock *sk2;
133 bool reuse = sk->sk_reuse;
134 bool reuseport = !!sk->sk_reuseport && reuseport_ok;
135 kuid_t uid = sock_i_uid((struct sock *)sk);
136
137 /*
138 * Unlike other sk lookup places we do not check
139 * for sk_net here, since _all_ the socks listed
140 * in tb->owners list belong to the same net - the
141 * one this bucket belongs to.
142 */
143
144 sk_for_each_bound(sk2, &tb->owners) {
145 if (sk != sk2 &&
146 (!sk->sk_bound_dev_if ||
147 !sk2->sk_bound_dev_if ||
148 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
149 if ((!reuse || !sk2->sk_reuse ||
150 sk2->sk_state == TCP_LISTEN) &&
151 (!reuseport || !sk2->sk_reuseport ||
152 rcu_access_pointer(sk->sk_reuseport_cb) ||
153 (sk2->sk_state != TCP_TIME_WAIT &&
154 !uid_eq(uid, sock_i_uid(sk2))))) {
155 if (inet_rcv_saddr_equal(sk, sk2, true))
156 break;
157 }
158 if (!relax && reuse && sk2->sk_reuse &&
159 sk2->sk_state != TCP_LISTEN) {
160 if (inet_rcv_saddr_equal(sk, sk2, true))
161 break;
162 }
163 }
164 }
165 return sk2 != NULL;
166}
167
168/*
169 * Find an open port number for the socket. Returns with the
170 * inet_bind_hashbucket lock held.
171 */
172static struct inet_bind_hashbucket *
173inet_csk_find_open_port(struct sock *sk, struct inet_bind_bucket **tb_ret, int *port_ret)
174{
175 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
176 int port = 0;
177 struct inet_bind_hashbucket *head;
178 struct net *net = sock_net(sk);
179 int i, low, high, attempt_half;
180 struct inet_bind_bucket *tb;
181 u32 remaining, offset;
182
183 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
184other_half_scan:
185 inet_get_local_port_range(net, &low, &high);
186 high++; /* [32768, 60999] -> [32768, 61000[ */
187 if (high - low < 4)
188 attempt_half = 0;
189 if (attempt_half) {
190 int half = low + (((high - low) >> 2) << 1);
191
192 if (attempt_half == 1)
193 high = half;
194 else
195 low = half;
196 }
197 remaining = high - low;
198 if (likely(remaining > 1))
199 remaining &= ~1U;
200
201 offset = prandom_u32() % remaining;
202 /* __inet_hash_connect() favors ports having @low parity
203 * We do the opposite to not pollute connect() users.
204 */
205 offset |= 1U;
206
207other_parity_scan:
208 port = low + offset;
209 for (i = 0; i < remaining; i += 2, port += 2) {
210 if (unlikely(port >= high))
211 port -= remaining;
212 if (inet_is_local_reserved_port(net, port))
213 continue;
214 head = &hinfo->bhash[inet_bhashfn(net, port,
215 hinfo->bhash_size)];
216 spin_lock_bh(&head->lock);
217 inet_bind_bucket_for_each(tb, &head->chain)
218 if (net_eq(ib_net(tb), net) && tb->port == port) {
219 if (!inet_csk_bind_conflict(sk, tb, false, false))
220 goto success;
221 goto next_port;
222 }
223 tb = NULL;
224 goto success;
225next_port:
226 spin_unlock_bh(&head->lock);
227 cond_resched();
228 }
229
230 offset--;
231 if (!(offset & 1))
232 goto other_parity_scan;
233
234 if (attempt_half == 1) {
235 /* OK we now try the upper half of the range */
236 attempt_half = 2;
237 goto other_half_scan;
238 }
239 return NULL;
240success:
241 *port_ret = port;
242 *tb_ret = tb;
243 return head;
244}
245
246static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
247 struct sock *sk)
248{
249 kuid_t uid = sock_i_uid(sk);
250
251 if (tb->fastreuseport <= 0)
252 return 0;
253 if (!sk->sk_reuseport)
254 return 0;
255 if (rcu_access_pointer(sk->sk_reuseport_cb))
256 return 0;
257 if (!uid_eq(tb->fastuid, uid))
258 return 0;
259 /* We only need to check the rcv_saddr if this tb was once marked
260 * without fastreuseport and then was reset, as we can only know that
261 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
262 * owners list.
263 */
264 if (tb->fastreuseport == FASTREUSEPORT_ANY)
265 return 1;
266#if IS_ENABLED(CONFIG_IPV6)
267 if (tb->fast_sk_family == AF_INET6)
268 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
269 inet6_rcv_saddr(sk),
270 tb->fast_rcv_saddr,
271 sk->sk_rcv_saddr,
272 tb->fast_ipv6_only,
273 ipv6_only_sock(sk), true);
274#endif
275 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
276 ipv6_only_sock(sk), true);
277}
278
279/* Obtain a reference to a local port for the given sock,
280 * if snum is zero it means select any available local port.
281 * We try to allocate an odd port (and leave even ports for connect())
282 */
283int inet_csk_get_port(struct sock *sk, unsigned short snum)
284{
285 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
286 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
287 int ret = 1, port = snum;
288 struct inet_bind_hashbucket *head;
289 struct net *net = sock_net(sk);
290 struct inet_bind_bucket *tb = NULL;
291 kuid_t uid = sock_i_uid(sk);
292
293 if (!port) {
294 head = inet_csk_find_open_port(sk, &tb, &port);
295 if (!head)
296 return ret;
297 if (!tb)
298 goto tb_not_found;
299 goto success;
300 }
301 head = &hinfo->bhash[inet_bhashfn(net, port,
302 hinfo->bhash_size)];
303 spin_lock_bh(&head->lock);
304 inet_bind_bucket_for_each(tb, &head->chain)
305 if (net_eq(ib_net(tb), net) && tb->port == port)
306 goto tb_found;
307tb_not_found:
308 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
309 net, head, port);
310 if (!tb)
311 goto fail_unlock;
312tb_found:
313 if (!hlist_empty(&tb->owners)) {
314 if (sk->sk_reuse == SK_FORCE_REUSE)
315 goto success;
316
317 if ((tb->fastreuse > 0 && reuse) ||
318 sk_reuseport_match(tb, sk))
319 goto success;
320 if (inet_csk_bind_conflict(sk, tb, true, true))
321 goto fail_unlock;
322 }
323success:
324 if (hlist_empty(&tb->owners)) {
325 tb->fastreuse = reuse;
326 if (sk->sk_reuseport) {
327 tb->fastreuseport = FASTREUSEPORT_ANY;
328 tb->fastuid = uid;
329 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
330 tb->fast_ipv6_only = ipv6_only_sock(sk);
331 tb->fast_sk_family = sk->sk_family;
332#if IS_ENABLED(CONFIG_IPV6)
333 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
334#endif
335 } else {
336 tb->fastreuseport = 0;
337 }
338 } else {
339 if (!reuse)
340 tb->fastreuse = 0;
341 if (sk->sk_reuseport) {
342 /* We didn't match or we don't have fastreuseport set on
343 * the tb, but we have sk_reuseport set on this socket
344 * and we know that there are no bind conflicts with
345 * this socket in this tb, so reset our tb's reuseport
346 * settings so that any subsequent sockets that match
347 * our current socket will be put on the fast path.
348 *
349 * If we reset we need to set FASTREUSEPORT_STRICT so we
350 * do extra checking for all subsequent sk_reuseport
351 * socks.
352 */
353 if (!sk_reuseport_match(tb, sk)) {
354 tb->fastreuseport = FASTREUSEPORT_STRICT;
355 tb->fastuid = uid;
356 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
357 tb->fast_ipv6_only = ipv6_only_sock(sk);
358 tb->fast_sk_family = sk->sk_family;
359#if IS_ENABLED(CONFIG_IPV6)
360 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
361#endif
362 }
363 } else {
364 tb->fastreuseport = 0;
365 }
366 }
367 if (!inet_csk(sk)->icsk_bind_hash)
368 inet_bind_hash(sk, tb, port);
369 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
370 ret = 0;
371
372fail_unlock:
373 spin_unlock_bh(&head->lock);
374 return ret;
375}
376EXPORT_SYMBOL_GPL(inet_csk_get_port);
377
378/*
379 * Wait for an incoming connection, avoid race conditions. This must be called
380 * with the socket locked.
381 */
382static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
383{
384 struct inet_connection_sock *icsk = inet_csk(sk);
385 DEFINE_WAIT(wait);
386 int err;
387
388 /*
389 * True wake-one mechanism for incoming connections: only
390 * one process gets woken up, not the 'whole herd'.
391 * Since we do not 'race & poll' for established sockets
392 * anymore, the common case will execute the loop only once.
393 *
394 * Subtle issue: "add_wait_queue_exclusive()" will be added
395 * after any current non-exclusive waiters, and we know that
396 * it will always _stay_ after any new non-exclusive waiters
397 * because all non-exclusive waiters are added at the
398 * beginning of the wait-queue. As such, it's ok to "drop"
399 * our exclusiveness temporarily when we get woken up without
400 * having to remove and re-insert us on the wait queue.
401 */
402 for (;;) {
403 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
404 TASK_INTERRUPTIBLE);
405 release_sock(sk);
406 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
407 timeo = schedule_timeout(timeo);
408 sched_annotate_sleep();
409 lock_sock(sk);
410 err = 0;
411 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
412 break;
413 err = -EINVAL;
414 if (sk->sk_state != TCP_LISTEN)
415 break;
416 err = sock_intr_errno(timeo);
417 if (signal_pending(current))
418 break;
419 err = -EAGAIN;
420 if (!timeo)
421 break;
422 }
423 finish_wait(sk_sleep(sk), &wait);
424 return err;
425}
426
427/*
428 * This will accept the next outstanding connection.
429 */
430struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
431{
432 struct inet_connection_sock *icsk = inet_csk(sk);
433 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
434 struct request_sock *req;
435 struct sock *newsk;
436 int error;
437
438 lock_sock(sk);
439
440 /* We need to make sure that this socket is listening,
441 * and that it has something pending.
442 */
443 error = -EINVAL;
444 if (sk->sk_state != TCP_LISTEN)
445 goto out_err;
446
447 /* Find already established connection */
448 if (reqsk_queue_empty(queue)) {
449 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
450
451 /* If this is a non blocking socket don't sleep */
452 error = -EAGAIN;
453 if (!timeo)
454 goto out_err;
455
456 error = inet_csk_wait_for_connect(sk, timeo);
457 if (error)
458 goto out_err;
459 }
460 req = reqsk_queue_remove(queue, sk);
461 newsk = req->sk;
462
463 if (sk->sk_protocol == IPPROTO_TCP &&
464 tcp_rsk(req)->tfo_listener) {
465 spin_lock_bh(&queue->fastopenq.lock);
466 if (tcp_rsk(req)->tfo_listener) {
467 /* We are still waiting for the final ACK from 3WHS
468 * so can't free req now. Instead, we set req->sk to
469 * NULL to signify that the child socket is taken
470 * so reqsk_fastopen_remove() will free the req
471 * when 3WHS finishes (or is aborted).
472 */
473 req->sk = NULL;
474 req = NULL;
475 }
476 spin_unlock_bh(&queue->fastopenq.lock);
477 }
478out:
479 release_sock(sk);
480 if (req)
481 reqsk_put(req);
482 return newsk;
483out_err:
484 newsk = NULL;
485 req = NULL;
486 *err = error;
487 goto out;
488}
489EXPORT_SYMBOL(inet_csk_accept);
490
491/*
492 * Using different timers for retransmit, delayed acks and probes
493 * We may wish use just one timer maintaining a list of expire jiffies
494 * to optimize.
495 */
496void inet_csk_init_xmit_timers(struct sock *sk,
497 void (*retransmit_handler)(struct timer_list *t),
498 void (*delack_handler)(struct timer_list *t),
499 void (*keepalive_handler)(struct timer_list *t))
500{
501 struct inet_connection_sock *icsk = inet_csk(sk);
502
503 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
504 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
505 timer_setup(&sk->sk_timer, keepalive_handler, 0);
506 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
507}
508EXPORT_SYMBOL(inet_csk_init_xmit_timers);
509
510void inet_csk_clear_xmit_timers(struct sock *sk)
511{
512 struct inet_connection_sock *icsk = inet_csk(sk);
513
514 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
515
516 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
517 sk_stop_timer(sk, &icsk->icsk_delack_timer);
518 sk_stop_timer(sk, &sk->sk_timer);
519}
520EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
521
522void inet_csk_delete_keepalive_timer(struct sock *sk)
523{
524 sk_stop_timer(sk, &sk->sk_timer);
525}
526EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
527
528void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
529{
530 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
531}
532EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
533
534struct dst_entry *inet_csk_route_req(const struct sock *sk,
535 struct flowi4 *fl4,
536 const struct request_sock *req)
537{
538 const struct inet_request_sock *ireq = inet_rsk(req);
539 struct net *net = read_pnet(&ireq->ireq_net);
540 struct ip_options_rcu *opt;
541 struct rtable *rt;
542
543 opt = ireq_opt_deref(ireq);
544
545 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
546 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
547 sk->sk_protocol, inet_sk_flowi_flags(sk),
548 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
549 ireq->ir_loc_addr, ireq->ir_rmt_port,
550 htons(ireq->ir_num), sk->sk_uid);
551 security_req_classify_flow(req, flowi4_to_flowi(fl4));
552 rt = ip_route_output_flow(net, fl4, sk);
553 if (IS_ERR(rt))
554 goto no_route;
555 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
556 goto route_err;
557 return &rt->dst;
558
559route_err:
560 ip_rt_put(rt);
561no_route:
562 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
563 return NULL;
564}
565EXPORT_SYMBOL_GPL(inet_csk_route_req);
566
567struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
568 struct sock *newsk,
569 const struct request_sock *req)
570{
571 const struct inet_request_sock *ireq = inet_rsk(req);
572 struct net *net = read_pnet(&ireq->ireq_net);
573 struct inet_sock *newinet = inet_sk(newsk);
574 struct ip_options_rcu *opt;
575 struct flowi4 *fl4;
576 struct rtable *rt;
577
578 opt = rcu_dereference(ireq->ireq_opt);
579 fl4 = &newinet->cork.fl.u.ip4;
580
581 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
582 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
583 sk->sk_protocol, inet_sk_flowi_flags(sk),
584 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
585 ireq->ir_loc_addr, ireq->ir_rmt_port,
586 htons(ireq->ir_num), sk->sk_uid);
587 security_req_classify_flow(req, flowi4_to_flowi(fl4));
588 rt = ip_route_output_flow(net, fl4, sk);
589 if (IS_ERR(rt))
590 goto no_route;
591 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
592 goto route_err;
593 return &rt->dst;
594
595route_err:
596 ip_rt_put(rt);
597no_route:
598 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
599 return NULL;
600}
601EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
602
603#if IS_ENABLED(CONFIG_IPV6)
604#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
605#else
606#define AF_INET_FAMILY(fam) true
607#endif
608
609/* Decide when to expire the request and when to resend SYN-ACK */
610static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
611 const int max_retries,
612 const u8 rskq_defer_accept,
613 int *expire, int *resend)
614{
615 if (!rskq_defer_accept) {
616 *expire = req->num_timeout >= thresh;
617 *resend = 1;
618 return;
619 }
620 *expire = req->num_timeout >= thresh &&
621 (!inet_rsk(req)->acked || req->num_timeout >= max_retries);
622 /*
623 * Do not resend while waiting for data after ACK,
624 * start to resend on end of deferring period to give
625 * last chance for data or ACK to create established socket.
626 */
627 *resend = !inet_rsk(req)->acked ||
628 req->num_timeout >= rskq_defer_accept - 1;
629}
630
631int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
632{
633 int err = req->rsk_ops->rtx_syn_ack(parent, req);
634
635 if (!err)
636 req->num_retrans++;
637 return err;
638}
639EXPORT_SYMBOL(inet_rtx_syn_ack);
640
641/* return true if req was found in the ehash table */
642static bool reqsk_queue_unlink(struct request_sock_queue *queue,
643 struct request_sock *req)
644{
645 struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo;
646 bool found = false;
647
648 if (sk_hashed(req_to_sk(req))) {
649 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
650
651 spin_lock(lock);
652 found = __sk_nulls_del_node_init_rcu(req_to_sk(req));
653 spin_unlock(lock);
654 }
655 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
656 reqsk_put(req);
657 return found;
658}
659
660void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
661{
662 if (reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req)) {
663 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
664 reqsk_put(req);
665 }
666}
667EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
668
669void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
670{
671 inet_csk_reqsk_queue_drop(sk, req);
672 reqsk_put(req);
673}
674EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
675
676static void reqsk_timer_handler(struct timer_list *t)
677{
678 struct request_sock *req = from_timer(req, t, rsk_timer);
679 struct sock *sk_listener = req->rsk_listener;
680 struct net *net = sock_net(sk_listener);
681 struct inet_connection_sock *icsk = inet_csk(sk_listener);
682 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
683 int qlen, expire = 0, resend = 0;
684 int max_retries, thresh;
685 u8 defer_accept;
686
687 if (inet_sk_state_load(sk_listener) != TCP_LISTEN)
688 goto drop;
689
690 max_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries;
691 thresh = max_retries;
692 /* Normally all the openreqs are young and become mature
693 * (i.e. converted to established socket) for first timeout.
694 * If synack was not acknowledged for 1 second, it means
695 * one of the following things: synack was lost, ack was lost,
696 * rtt is high or nobody planned to ack (i.e. synflood).
697 * When server is a bit loaded, queue is populated with old
698 * open requests, reducing effective size of queue.
699 * When server is well loaded, queue size reduces to zero
700 * after several minutes of work. It is not synflood,
701 * it is normal operation. The solution is pruning
702 * too old entries overriding normal timeout, when
703 * situation becomes dangerous.
704 *
705 * Essentially, we reserve half of room for young
706 * embrions; and abort old ones without pity, if old
707 * ones are about to clog our table.
708 */
709 qlen = reqsk_queue_len(queue);
710 if ((qlen << 1) > max(8U, sk_listener->sk_max_ack_backlog)) {
711 int young = reqsk_queue_len_young(queue) << 1;
712
713 while (thresh > 2) {
714 if (qlen < young)
715 break;
716 thresh--;
717 young <<= 1;
718 }
719 }
720 defer_accept = READ_ONCE(queue->rskq_defer_accept);
721 if (defer_accept)
722 max_retries = defer_accept;
723 syn_ack_recalc(req, thresh, max_retries, defer_accept,
724 &expire, &resend);
725 req->rsk_ops->syn_ack_timeout(req);
726 if (!expire &&
727 (!resend ||
728 !inet_rtx_syn_ack(sk_listener, req) ||
729 inet_rsk(req)->acked)) {
730 unsigned long timeo;
731
732 if (req->num_timeout++ == 0)
733 atomic_dec(&queue->young);
734 timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
735 mod_timer(&req->rsk_timer, jiffies + timeo);
736 return;
737 }
738drop:
739 inet_csk_reqsk_queue_drop_and_put(sk_listener, req);
740}
741
742static void reqsk_queue_hash_req(struct request_sock *req,
743 unsigned long timeout)
744{
745 req->num_retrans = 0;
746 req->num_timeout = 0;
747 req->sk = NULL;
748
749 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
750 mod_timer(&req->rsk_timer, jiffies + timeout);
751
752 inet_ehash_insert(req_to_sk(req), NULL);
753 /* before letting lookups find us, make sure all req fields
754 * are committed to memory and refcnt initialized.
755 */
756 smp_wmb();
757 refcount_set(&req->rsk_refcnt, 2 + 1);
758}
759
760void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
761 unsigned long timeout)
762{
763 reqsk_queue_hash_req(req, timeout);
764 inet_csk_reqsk_queue_added(sk);
765}
766EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
767
768/**
769 * inet_csk_clone_lock - clone an inet socket, and lock its clone
770 * @sk: the socket to clone
771 * @req: request_sock
772 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
773 *
774 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
775 */
776struct sock *inet_csk_clone_lock(const struct sock *sk,
777 const struct request_sock *req,
778 const gfp_t priority)
779{
780 struct sock *newsk = sk_clone_lock(sk, priority);
781
782 if (newsk) {
783 struct inet_connection_sock *newicsk = inet_csk(newsk);
784
785 inet_sk_set_state(newsk, TCP_SYN_RECV);
786 newicsk->icsk_bind_hash = NULL;
787
788 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
789 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
790 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
791
792 /* listeners have SOCK_RCU_FREE, not the children */
793 sock_reset_flag(newsk, SOCK_RCU_FREE);
794
795 inet_sk(newsk)->mc_list = NULL;
796
797 newsk->sk_mark = inet_rsk(req)->ir_mark;
798 atomic64_set(&newsk->sk_cookie,
799 atomic64_read(&inet_rsk(req)->ir_cookie));
800
801 newicsk->icsk_retransmits = 0;
802 newicsk->icsk_backoff = 0;
803 newicsk->icsk_probes_out = 0;
804
805 /* Deinitialize accept_queue to trap illegal accesses. */
806 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
807
808 security_inet_csk_clone(newsk, req);
809 }
810 return newsk;
811}
812EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
813
814/*
815 * At this point, there should be no process reference to this
816 * socket, and thus no user references at all. Therefore we
817 * can assume the socket waitqueue is inactive and nobody will
818 * try to jump onto it.
819 */
820void inet_csk_destroy_sock(struct sock *sk)
821{
822 WARN_ON(sk->sk_state != TCP_CLOSE);
823 WARN_ON(!sock_flag(sk, SOCK_DEAD));
824
825 /* It cannot be in hash table! */
826 WARN_ON(!sk_unhashed(sk));
827
828 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
829 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
830
831 sk->sk_prot->destroy(sk);
832
833 sk_stream_kill_queues(sk);
834
835 xfrm_sk_free_policy(sk);
836
837 sk_refcnt_debug_release(sk);
838
839 percpu_counter_dec(sk->sk_prot->orphan_count);
840
841 sock_put(sk);
842}
843EXPORT_SYMBOL(inet_csk_destroy_sock);
844
845/* This function allows to force a closure of a socket after the call to
846 * tcp/dccp_create_openreq_child().
847 */
848void inet_csk_prepare_forced_close(struct sock *sk)
849 __releases(&sk->sk_lock.slock)
850{
851 /* sk_clone_lock locked the socket and set refcnt to 2 */
852 bh_unlock_sock(sk);
853 sock_put(sk);
854
855 /* The below has to be done to allow calling inet_csk_destroy_sock */
856 sock_set_flag(sk, SOCK_DEAD);
857 percpu_counter_inc(sk->sk_prot->orphan_count);
858 inet_sk(sk)->inet_num = 0;
859}
860EXPORT_SYMBOL(inet_csk_prepare_forced_close);
861
862int inet_csk_listen_start(struct sock *sk, int backlog)
863{
864 struct inet_connection_sock *icsk = inet_csk(sk);
865 struct inet_sock *inet = inet_sk(sk);
866 int err = -EADDRINUSE;
867
868 reqsk_queue_alloc(&icsk->icsk_accept_queue);
869
870 sk->sk_max_ack_backlog = backlog;
871 sk->sk_ack_backlog = 0;
872 inet_csk_delack_init(sk);
873
874 /* There is race window here: we announce ourselves listening,
875 * but this transition is still not validated by get_port().
876 * It is OK, because this socket enters to hash table only
877 * after validation is complete.
878 */
879 inet_sk_state_store(sk, TCP_LISTEN);
880 if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
881 inet->inet_sport = htons(inet->inet_num);
882
883 sk_dst_reset(sk);
884 err = sk->sk_prot->hash(sk);
885
886 if (likely(!err))
887 return 0;
888 }
889
890 inet_sk_set_state(sk, TCP_CLOSE);
891 return err;
892}
893EXPORT_SYMBOL_GPL(inet_csk_listen_start);
894
895static void inet_child_forget(struct sock *sk, struct request_sock *req,
896 struct sock *child)
897{
898 sk->sk_prot->disconnect(child, O_NONBLOCK);
899
900 sock_orphan(child);
901
902 percpu_counter_inc(sk->sk_prot->orphan_count);
903
904 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
905 BUG_ON(tcp_sk(child)->fastopen_rsk != req);
906 BUG_ON(sk != req->rsk_listener);
907
908 /* Paranoid, to prevent race condition if
909 * an inbound pkt destined for child is
910 * blocked by sock lock in tcp_v4_rcv().
911 * Also to satisfy an assertion in
912 * tcp_v4_destroy_sock().
913 */
914 tcp_sk(child)->fastopen_rsk = NULL;
915 }
916 inet_csk_destroy_sock(child);
917}
918
919struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
920 struct request_sock *req,
921 struct sock *child)
922{
923 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
924
925 spin_lock(&queue->rskq_lock);
926 if (unlikely(sk->sk_state != TCP_LISTEN)) {
927 inet_child_forget(sk, req, child);
928 child = NULL;
929 } else {
930 req->sk = child;
931 req->dl_next = NULL;
932 if (queue->rskq_accept_head == NULL)
933 queue->rskq_accept_head = req;
934 else
935 queue->rskq_accept_tail->dl_next = req;
936 queue->rskq_accept_tail = req;
937 sk_acceptq_added(sk);
938 }
939 spin_unlock(&queue->rskq_lock);
940 return child;
941}
942EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
943
944struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
945 struct request_sock *req, bool own_req)
946{
947 if (own_req) {
948 inet_csk_reqsk_queue_drop(sk, req);
949 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
950 if (inet_csk_reqsk_queue_add(sk, req, child))
951 return child;
952 }
953 /* Too bad, another child took ownership of the request, undo. */
954 bh_unlock_sock(child);
955 sock_put(child);
956 return NULL;
957}
958EXPORT_SYMBOL(inet_csk_complete_hashdance);
959
960/*
961 * This routine closes sockets which have been at least partially
962 * opened, but not yet accepted.
963 */
964void inet_csk_listen_stop(struct sock *sk)
965{
966 struct inet_connection_sock *icsk = inet_csk(sk);
967 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
968 struct request_sock *next, *req;
969
970 /* Following specs, it would be better either to send FIN
971 * (and enter FIN-WAIT-1, it is normal close)
972 * or to send active reset (abort).
973 * Certainly, it is pretty dangerous while synflood, but it is
974 * bad justification for our negligence 8)
975 * To be honest, we are not able to make either
976 * of the variants now. --ANK
977 */
978 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
979 struct sock *child = req->sk;
980
981 local_bh_disable();
982 bh_lock_sock(child);
983 WARN_ON(sock_owned_by_user(child));
984 sock_hold(child);
985
986 inet_child_forget(sk, req, child);
987 reqsk_put(req);
988 bh_unlock_sock(child);
989 local_bh_enable();
990 sock_put(child);
991
992 cond_resched();
993 }
994 if (queue->fastopenq.rskq_rst_head) {
995 /* Free all the reqs queued in rskq_rst_head. */
996 spin_lock_bh(&queue->fastopenq.lock);
997 req = queue->fastopenq.rskq_rst_head;
998 queue->fastopenq.rskq_rst_head = NULL;
999 spin_unlock_bh(&queue->fastopenq.lock);
1000 while (req != NULL) {
1001 next = req->dl_next;
1002 reqsk_put(req);
1003 req = next;
1004 }
1005 }
1006 WARN_ON_ONCE(sk->sk_ack_backlog);
1007}
1008EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1009
1010void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1011{
1012 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1013 const struct inet_sock *inet = inet_sk(sk);
1014
1015 sin->sin_family = AF_INET;
1016 sin->sin_addr.s_addr = inet->inet_daddr;
1017 sin->sin_port = inet->inet_dport;
1018}
1019EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1020
1021#ifdef CONFIG_COMPAT
1022int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
1023 char __user *optval, int __user *optlen)
1024{
1025 const struct inet_connection_sock *icsk = inet_csk(sk);
1026
1027 if (icsk->icsk_af_ops->compat_getsockopt)
1028 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
1029 optval, optlen);
1030 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
1031 optval, optlen);
1032}
1033EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
1034
1035int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
1036 char __user *optval, unsigned int optlen)
1037{
1038 const struct inet_connection_sock *icsk = inet_csk(sk);
1039
1040 if (icsk->icsk_af_ops->compat_setsockopt)
1041 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
1042 optval, optlen);
1043 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1044 optval, optlen);
1045}
1046EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
1047#endif
1048
1049static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1050{
1051 const struct inet_sock *inet = inet_sk(sk);
1052 const struct ip_options_rcu *inet_opt;
1053 __be32 daddr = inet->inet_daddr;
1054 struct flowi4 *fl4;
1055 struct rtable *rt;
1056
1057 rcu_read_lock();
1058 inet_opt = rcu_dereference(inet->inet_opt);
1059 if (inet_opt && inet_opt->opt.srr)
1060 daddr = inet_opt->opt.faddr;
1061 fl4 = &fl->u.ip4;
1062 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
1063 inet->inet_saddr, inet->inet_dport,
1064 inet->inet_sport, sk->sk_protocol,
1065 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
1066 if (IS_ERR(rt))
1067 rt = NULL;
1068 if (rt)
1069 sk_setup_caps(sk, &rt->dst);
1070 rcu_read_unlock();
1071
1072 return &rt->dst;
1073}
1074
1075struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1076{
1077 struct dst_entry *dst = __sk_dst_check(sk, 0);
1078 struct inet_sock *inet = inet_sk(sk);
1079
1080 if (!dst) {
1081 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1082 if (!dst)
1083 goto out;
1084 }
1085 dst->ops->update_pmtu(dst, sk, NULL, mtu);
1086
1087 dst = __sk_dst_check(sk, 0);
1088 if (!dst)
1089 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1090out:
1091 return dst;
1092}
1093EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Support for INET connection oriented protocols.
8 *
9 * Authors: See the TCP sources
10 */
11
12#include <linux/module.h>
13#include <linux/jhash.h>
14
15#include <net/inet_connection_sock.h>
16#include <net/inet_hashtables.h>
17#include <net/inet_timewait_sock.h>
18#include <net/ip.h>
19#include <net/route.h>
20#include <net/tcp_states.h>
21#include <net/xfrm.h>
22#include <net/tcp.h>
23#include <net/sock_reuseport.h>
24#include <net/addrconf.h>
25
26#if IS_ENABLED(CONFIG_IPV6)
27/* match_sk*_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses
28 * if IPv6 only, and any IPv4 addresses
29 * if not IPv6 only
30 * match_sk*_wildcard == false: addresses must be exactly the same, i.e.
31 * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
32 * and 0.0.0.0 equals to 0.0.0.0 only
33 */
34static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6,
35 const struct in6_addr *sk2_rcv_saddr6,
36 __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
37 bool sk1_ipv6only, bool sk2_ipv6only,
38 bool match_sk1_wildcard,
39 bool match_sk2_wildcard)
40{
41 int addr_type = ipv6_addr_type(sk1_rcv_saddr6);
42 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
43
44 /* if both are mapped, treat as IPv4 */
45 if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
46 if (!sk2_ipv6only) {
47 if (sk1_rcv_saddr == sk2_rcv_saddr)
48 return true;
49 return (match_sk1_wildcard && !sk1_rcv_saddr) ||
50 (match_sk2_wildcard && !sk2_rcv_saddr);
51 }
52 return false;
53 }
54
55 if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
56 return true;
57
58 if (addr_type2 == IPV6_ADDR_ANY && match_sk2_wildcard &&
59 !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
60 return true;
61
62 if (addr_type == IPV6_ADDR_ANY && match_sk1_wildcard &&
63 !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
64 return true;
65
66 if (sk2_rcv_saddr6 &&
67 ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6))
68 return true;
69
70 return false;
71}
72#endif
73
74/* match_sk*_wildcard == true: 0.0.0.0 equals to any IPv4 addresses
75 * match_sk*_wildcard == false: addresses must be exactly the same, i.e.
76 * 0.0.0.0 only equals to 0.0.0.0
77 */
78static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
79 bool sk2_ipv6only, bool match_sk1_wildcard,
80 bool match_sk2_wildcard)
81{
82 if (!sk2_ipv6only) {
83 if (sk1_rcv_saddr == sk2_rcv_saddr)
84 return true;
85 return (match_sk1_wildcard && !sk1_rcv_saddr) ||
86 (match_sk2_wildcard && !sk2_rcv_saddr);
87 }
88 return false;
89}
90
91bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
92 bool match_wildcard)
93{
94#if IS_ENABLED(CONFIG_IPV6)
95 if (sk->sk_family == AF_INET6)
96 return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr,
97 inet6_rcv_saddr(sk2),
98 sk->sk_rcv_saddr,
99 sk2->sk_rcv_saddr,
100 ipv6_only_sock(sk),
101 ipv6_only_sock(sk2),
102 match_wildcard,
103 match_wildcard);
104#endif
105 return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr,
106 ipv6_only_sock(sk2), match_wildcard,
107 match_wildcard);
108}
109EXPORT_SYMBOL(inet_rcv_saddr_equal);
110
111bool inet_rcv_saddr_any(const struct sock *sk)
112{
113#if IS_ENABLED(CONFIG_IPV6)
114 if (sk->sk_family == AF_INET6)
115 return ipv6_addr_any(&sk->sk_v6_rcv_saddr);
116#endif
117 return !sk->sk_rcv_saddr;
118}
119
120void inet_get_local_port_range(struct net *net, int *low, int *high)
121{
122 unsigned int seq;
123
124 do {
125 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
126
127 *low = net->ipv4.ip_local_ports.range[0];
128 *high = net->ipv4.ip_local_ports.range[1];
129 } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
130}
131EXPORT_SYMBOL(inet_get_local_port_range);
132
133static bool inet_use_bhash2_on_bind(const struct sock *sk)
134{
135#if IS_ENABLED(CONFIG_IPV6)
136 if (sk->sk_family == AF_INET6) {
137 int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr);
138
139 return addr_type != IPV6_ADDR_ANY &&
140 addr_type != IPV6_ADDR_MAPPED;
141 }
142#endif
143 return sk->sk_rcv_saddr != htonl(INADDR_ANY);
144}
145
146static bool inet_bind_conflict(const struct sock *sk, struct sock *sk2,
147 kuid_t sk_uid, bool relax,
148 bool reuseport_cb_ok, bool reuseport_ok)
149{
150 int bound_dev_if2;
151
152 if (sk == sk2)
153 return false;
154
155 bound_dev_if2 = READ_ONCE(sk2->sk_bound_dev_if);
156
157 if (!sk->sk_bound_dev_if || !bound_dev_if2 ||
158 sk->sk_bound_dev_if == bound_dev_if2) {
159 if (sk->sk_reuse && sk2->sk_reuse &&
160 sk2->sk_state != TCP_LISTEN) {
161 if (!relax || (!reuseport_ok && sk->sk_reuseport &&
162 sk2->sk_reuseport && reuseport_cb_ok &&
163 (sk2->sk_state == TCP_TIME_WAIT ||
164 uid_eq(sk_uid, sock_i_uid(sk2)))))
165 return true;
166 } else if (!reuseport_ok || !sk->sk_reuseport ||
167 !sk2->sk_reuseport || !reuseport_cb_ok ||
168 (sk2->sk_state != TCP_TIME_WAIT &&
169 !uid_eq(sk_uid, sock_i_uid(sk2)))) {
170 return true;
171 }
172 }
173 return false;
174}
175
176static bool __inet_bhash2_conflict(const struct sock *sk, struct sock *sk2,
177 kuid_t sk_uid, bool relax,
178 bool reuseport_cb_ok, bool reuseport_ok)
179{
180 if (sk->sk_family == AF_INET && ipv6_only_sock(sk2))
181 return false;
182
183 return inet_bind_conflict(sk, sk2, sk_uid, relax,
184 reuseport_cb_ok, reuseport_ok);
185}
186
187static bool inet_bhash2_conflict(const struct sock *sk,
188 const struct inet_bind2_bucket *tb2,
189 kuid_t sk_uid,
190 bool relax, bool reuseport_cb_ok,
191 bool reuseport_ok)
192{
193 struct inet_timewait_sock *tw2;
194 struct sock *sk2;
195
196 sk_for_each_bound_bhash2(sk2, &tb2->owners) {
197 if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax,
198 reuseport_cb_ok, reuseport_ok))
199 return true;
200 }
201
202 twsk_for_each_bound_bhash2(tw2, &tb2->deathrow) {
203 sk2 = (struct sock *)tw2;
204
205 if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax,
206 reuseport_cb_ok, reuseport_ok))
207 return true;
208 }
209
210 return false;
211}
212
213/* This should be called only when the tb and tb2 hashbuckets' locks are held */
214static int inet_csk_bind_conflict(const struct sock *sk,
215 const struct inet_bind_bucket *tb,
216 const struct inet_bind2_bucket *tb2, /* may be null */
217 bool relax, bool reuseport_ok)
218{
219 bool reuseport_cb_ok;
220 struct sock_reuseport *reuseport_cb;
221 kuid_t uid = sock_i_uid((struct sock *)sk);
222
223 rcu_read_lock();
224 reuseport_cb = rcu_dereference(sk->sk_reuseport_cb);
225 /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */
226 reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks);
227 rcu_read_unlock();
228
229 /*
230 * Unlike other sk lookup places we do not check
231 * for sk_net here, since _all_ the socks listed
232 * in tb->owners and tb2->owners list belong
233 * to the same net - the one this bucket belongs to.
234 */
235
236 if (!inet_use_bhash2_on_bind(sk)) {
237 struct sock *sk2;
238
239 sk_for_each_bound(sk2, &tb->owners)
240 if (inet_bind_conflict(sk, sk2, uid, relax,
241 reuseport_cb_ok, reuseport_ok) &&
242 inet_rcv_saddr_equal(sk, sk2, true))
243 return true;
244
245 return false;
246 }
247
248 /* Conflicts with an existing IPV6_ADDR_ANY (if ipv6) or INADDR_ANY (if
249 * ipv4) should have been checked already. We need to do these two
250 * checks separately because their spinlocks have to be acquired/released
251 * independently of each other, to prevent possible deadlocks
252 */
253 return tb2 && inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok,
254 reuseport_ok);
255}
256
257/* Determine if there is a bind conflict with an existing IPV6_ADDR_ANY (if ipv6) or
258 * INADDR_ANY (if ipv4) socket.
259 *
260 * Caller must hold bhash hashbucket lock with local bh disabled, to protect
261 * against concurrent binds on the port for addr any
262 */
263static bool inet_bhash2_addr_any_conflict(const struct sock *sk, int port, int l3mdev,
264 bool relax, bool reuseport_ok)
265{
266 kuid_t uid = sock_i_uid((struct sock *)sk);
267 const struct net *net = sock_net(sk);
268 struct sock_reuseport *reuseport_cb;
269 struct inet_bind_hashbucket *head2;
270 struct inet_bind2_bucket *tb2;
271 bool reuseport_cb_ok;
272
273 rcu_read_lock();
274 reuseport_cb = rcu_dereference(sk->sk_reuseport_cb);
275 /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */
276 reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks);
277 rcu_read_unlock();
278
279 head2 = inet_bhash2_addr_any_hashbucket(sk, net, port);
280
281 spin_lock(&head2->lock);
282
283 inet_bind_bucket_for_each(tb2, &head2->chain)
284 if (inet_bind2_bucket_match_addr_any(tb2, net, port, l3mdev, sk))
285 break;
286
287 if (tb2 && inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok,
288 reuseport_ok)) {
289 spin_unlock(&head2->lock);
290 return true;
291 }
292
293 spin_unlock(&head2->lock);
294 return false;
295}
296
297/*
298 * Find an open port number for the socket. Returns with the
299 * inet_bind_hashbucket locks held if successful.
300 */
301static struct inet_bind_hashbucket *
302inet_csk_find_open_port(const struct sock *sk, struct inet_bind_bucket **tb_ret,
303 struct inet_bind2_bucket **tb2_ret,
304 struct inet_bind_hashbucket **head2_ret, int *port_ret)
305{
306 struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
307 int i, low, high, attempt_half, port, l3mdev;
308 struct inet_bind_hashbucket *head, *head2;
309 struct net *net = sock_net(sk);
310 struct inet_bind2_bucket *tb2;
311 struct inet_bind_bucket *tb;
312 u32 remaining, offset;
313 bool relax = false;
314
315 l3mdev = inet_sk_bound_l3mdev(sk);
316ports_exhausted:
317 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
318other_half_scan:
319 inet_get_local_port_range(net, &low, &high);
320 high++; /* [32768, 60999] -> [32768, 61000[ */
321 if (high - low < 4)
322 attempt_half = 0;
323 if (attempt_half) {
324 int half = low + (((high - low) >> 2) << 1);
325
326 if (attempt_half == 1)
327 high = half;
328 else
329 low = half;
330 }
331 remaining = high - low;
332 if (likely(remaining > 1))
333 remaining &= ~1U;
334
335 offset = get_random_u32_below(remaining);
336 /* __inet_hash_connect() favors ports having @low parity
337 * We do the opposite to not pollute connect() users.
338 */
339 offset |= 1U;
340
341other_parity_scan:
342 port = low + offset;
343 for (i = 0; i < remaining; i += 2, port += 2) {
344 if (unlikely(port >= high))
345 port -= remaining;
346 if (inet_is_local_reserved_port(net, port))
347 continue;
348 head = &hinfo->bhash[inet_bhashfn(net, port,
349 hinfo->bhash_size)];
350 spin_lock_bh(&head->lock);
351 if (inet_use_bhash2_on_bind(sk)) {
352 if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, relax, false))
353 goto next_port;
354 }
355
356 head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
357 spin_lock(&head2->lock);
358 tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk);
359 inet_bind_bucket_for_each(tb, &head->chain)
360 if (inet_bind_bucket_match(tb, net, port, l3mdev)) {
361 if (!inet_csk_bind_conflict(sk, tb, tb2,
362 relax, false))
363 goto success;
364 spin_unlock(&head2->lock);
365 goto next_port;
366 }
367 tb = NULL;
368 goto success;
369next_port:
370 spin_unlock_bh(&head->lock);
371 cond_resched();
372 }
373
374 offset--;
375 if (!(offset & 1))
376 goto other_parity_scan;
377
378 if (attempt_half == 1) {
379 /* OK we now try the upper half of the range */
380 attempt_half = 2;
381 goto other_half_scan;
382 }
383
384 if (READ_ONCE(net->ipv4.sysctl_ip_autobind_reuse) && !relax) {
385 /* We still have a chance to connect to different destinations */
386 relax = true;
387 goto ports_exhausted;
388 }
389 return NULL;
390success:
391 *port_ret = port;
392 *tb_ret = tb;
393 *tb2_ret = tb2;
394 *head2_ret = head2;
395 return head;
396}
397
398static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
399 struct sock *sk)
400{
401 kuid_t uid = sock_i_uid(sk);
402
403 if (tb->fastreuseport <= 0)
404 return 0;
405 if (!sk->sk_reuseport)
406 return 0;
407 if (rcu_access_pointer(sk->sk_reuseport_cb))
408 return 0;
409 if (!uid_eq(tb->fastuid, uid))
410 return 0;
411 /* We only need to check the rcv_saddr if this tb was once marked
412 * without fastreuseport and then was reset, as we can only know that
413 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
414 * owners list.
415 */
416 if (tb->fastreuseport == FASTREUSEPORT_ANY)
417 return 1;
418#if IS_ENABLED(CONFIG_IPV6)
419 if (tb->fast_sk_family == AF_INET6)
420 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
421 inet6_rcv_saddr(sk),
422 tb->fast_rcv_saddr,
423 sk->sk_rcv_saddr,
424 tb->fast_ipv6_only,
425 ipv6_only_sock(sk), true, false);
426#endif
427 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
428 ipv6_only_sock(sk), true, false);
429}
430
431void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
432 struct sock *sk)
433{
434 kuid_t uid = sock_i_uid(sk);
435 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
436
437 if (hlist_empty(&tb->owners)) {
438 tb->fastreuse = reuse;
439 if (sk->sk_reuseport) {
440 tb->fastreuseport = FASTREUSEPORT_ANY;
441 tb->fastuid = uid;
442 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
443 tb->fast_ipv6_only = ipv6_only_sock(sk);
444 tb->fast_sk_family = sk->sk_family;
445#if IS_ENABLED(CONFIG_IPV6)
446 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
447#endif
448 } else {
449 tb->fastreuseport = 0;
450 }
451 } else {
452 if (!reuse)
453 tb->fastreuse = 0;
454 if (sk->sk_reuseport) {
455 /* We didn't match or we don't have fastreuseport set on
456 * the tb, but we have sk_reuseport set on this socket
457 * and we know that there are no bind conflicts with
458 * this socket in this tb, so reset our tb's reuseport
459 * settings so that any subsequent sockets that match
460 * our current socket will be put on the fast path.
461 *
462 * If we reset we need to set FASTREUSEPORT_STRICT so we
463 * do extra checking for all subsequent sk_reuseport
464 * socks.
465 */
466 if (!sk_reuseport_match(tb, sk)) {
467 tb->fastreuseport = FASTREUSEPORT_STRICT;
468 tb->fastuid = uid;
469 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
470 tb->fast_ipv6_only = ipv6_only_sock(sk);
471 tb->fast_sk_family = sk->sk_family;
472#if IS_ENABLED(CONFIG_IPV6)
473 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
474#endif
475 }
476 } else {
477 tb->fastreuseport = 0;
478 }
479 }
480}
481
482/* Obtain a reference to a local port for the given sock,
483 * if snum is zero it means select any available local port.
484 * We try to allocate an odd port (and leave even ports for connect())
485 */
486int inet_csk_get_port(struct sock *sk, unsigned short snum)
487{
488 struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
489 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
490 bool found_port = false, check_bind_conflict = true;
491 bool bhash_created = false, bhash2_created = false;
492 int ret = -EADDRINUSE, port = snum, l3mdev;
493 struct inet_bind_hashbucket *head, *head2;
494 struct inet_bind2_bucket *tb2 = NULL;
495 struct inet_bind_bucket *tb = NULL;
496 bool head2_lock_acquired = false;
497 struct net *net = sock_net(sk);
498
499 l3mdev = inet_sk_bound_l3mdev(sk);
500
501 if (!port) {
502 head = inet_csk_find_open_port(sk, &tb, &tb2, &head2, &port);
503 if (!head)
504 return ret;
505
506 head2_lock_acquired = true;
507
508 if (tb && tb2)
509 goto success;
510 found_port = true;
511 } else {
512 head = &hinfo->bhash[inet_bhashfn(net, port,
513 hinfo->bhash_size)];
514 spin_lock_bh(&head->lock);
515 inet_bind_bucket_for_each(tb, &head->chain)
516 if (inet_bind_bucket_match(tb, net, port, l3mdev))
517 break;
518 }
519
520 if (!tb) {
521 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, net,
522 head, port, l3mdev);
523 if (!tb)
524 goto fail_unlock;
525 bhash_created = true;
526 }
527
528 if (!found_port) {
529 if (!hlist_empty(&tb->owners)) {
530 if (sk->sk_reuse == SK_FORCE_REUSE ||
531 (tb->fastreuse > 0 && reuse) ||
532 sk_reuseport_match(tb, sk))
533 check_bind_conflict = false;
534 }
535
536 if (check_bind_conflict && inet_use_bhash2_on_bind(sk)) {
537 if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, true, true))
538 goto fail_unlock;
539 }
540
541 head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
542 spin_lock(&head2->lock);
543 head2_lock_acquired = true;
544 tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk);
545 }
546
547 if (!tb2) {
548 tb2 = inet_bind2_bucket_create(hinfo->bind2_bucket_cachep,
549 net, head2, port, l3mdev, sk);
550 if (!tb2)
551 goto fail_unlock;
552 bhash2_created = true;
553 }
554
555 if (!found_port && check_bind_conflict) {
556 if (inet_csk_bind_conflict(sk, tb, tb2, true, true))
557 goto fail_unlock;
558 }
559
560success:
561 inet_csk_update_fastreuse(tb, sk);
562
563 if (!inet_csk(sk)->icsk_bind_hash)
564 inet_bind_hash(sk, tb, tb2, port);
565 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
566 WARN_ON(inet_csk(sk)->icsk_bind2_hash != tb2);
567 ret = 0;
568
569fail_unlock:
570 if (ret) {
571 if (bhash_created)
572 inet_bind_bucket_destroy(hinfo->bind_bucket_cachep, tb);
573 if (bhash2_created)
574 inet_bind2_bucket_destroy(hinfo->bind2_bucket_cachep,
575 tb2);
576 }
577 if (head2_lock_acquired)
578 spin_unlock(&head2->lock);
579 spin_unlock_bh(&head->lock);
580 return ret;
581}
582EXPORT_SYMBOL_GPL(inet_csk_get_port);
583
584/*
585 * Wait for an incoming connection, avoid race conditions. This must be called
586 * with the socket locked.
587 */
588static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
589{
590 struct inet_connection_sock *icsk = inet_csk(sk);
591 DEFINE_WAIT(wait);
592 int err;
593
594 /*
595 * True wake-one mechanism for incoming connections: only
596 * one process gets woken up, not the 'whole herd'.
597 * Since we do not 'race & poll' for established sockets
598 * anymore, the common case will execute the loop only once.
599 *
600 * Subtle issue: "add_wait_queue_exclusive()" will be added
601 * after any current non-exclusive waiters, and we know that
602 * it will always _stay_ after any new non-exclusive waiters
603 * because all non-exclusive waiters are added at the
604 * beginning of the wait-queue. As such, it's ok to "drop"
605 * our exclusiveness temporarily when we get woken up without
606 * having to remove and re-insert us on the wait queue.
607 */
608 for (;;) {
609 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
610 TASK_INTERRUPTIBLE);
611 release_sock(sk);
612 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
613 timeo = schedule_timeout(timeo);
614 sched_annotate_sleep();
615 lock_sock(sk);
616 err = 0;
617 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
618 break;
619 err = -EINVAL;
620 if (sk->sk_state != TCP_LISTEN)
621 break;
622 err = sock_intr_errno(timeo);
623 if (signal_pending(current))
624 break;
625 err = -EAGAIN;
626 if (!timeo)
627 break;
628 }
629 finish_wait(sk_sleep(sk), &wait);
630 return err;
631}
632
633/*
634 * This will accept the next outstanding connection.
635 */
636struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
637{
638 struct inet_connection_sock *icsk = inet_csk(sk);
639 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
640 struct request_sock *req;
641 struct sock *newsk;
642 int error;
643
644 lock_sock(sk);
645
646 /* We need to make sure that this socket is listening,
647 * and that it has something pending.
648 */
649 error = -EINVAL;
650 if (sk->sk_state != TCP_LISTEN)
651 goto out_err;
652
653 /* Find already established connection */
654 if (reqsk_queue_empty(queue)) {
655 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
656
657 /* If this is a non blocking socket don't sleep */
658 error = -EAGAIN;
659 if (!timeo)
660 goto out_err;
661
662 error = inet_csk_wait_for_connect(sk, timeo);
663 if (error)
664 goto out_err;
665 }
666 req = reqsk_queue_remove(queue, sk);
667 newsk = req->sk;
668
669 if (sk->sk_protocol == IPPROTO_TCP &&
670 tcp_rsk(req)->tfo_listener) {
671 spin_lock_bh(&queue->fastopenq.lock);
672 if (tcp_rsk(req)->tfo_listener) {
673 /* We are still waiting for the final ACK from 3WHS
674 * so can't free req now. Instead, we set req->sk to
675 * NULL to signify that the child socket is taken
676 * so reqsk_fastopen_remove() will free the req
677 * when 3WHS finishes (or is aborted).
678 */
679 req->sk = NULL;
680 req = NULL;
681 }
682 spin_unlock_bh(&queue->fastopenq.lock);
683 }
684
685out:
686 release_sock(sk);
687 if (newsk && mem_cgroup_sockets_enabled) {
688 int amt;
689
690 /* atomically get the memory usage, set and charge the
691 * newsk->sk_memcg.
692 */
693 lock_sock(newsk);
694
695 /* The socket has not been accepted yet, no need to look at
696 * newsk->sk_wmem_queued.
697 */
698 amt = sk_mem_pages(newsk->sk_forward_alloc +
699 atomic_read(&newsk->sk_rmem_alloc));
700 mem_cgroup_sk_alloc(newsk);
701 if (newsk->sk_memcg && amt)
702 mem_cgroup_charge_skmem(newsk->sk_memcg, amt,
703 GFP_KERNEL | __GFP_NOFAIL);
704
705 release_sock(newsk);
706 }
707 if (req)
708 reqsk_put(req);
709 return newsk;
710out_err:
711 newsk = NULL;
712 req = NULL;
713 *err = error;
714 goto out;
715}
716EXPORT_SYMBOL(inet_csk_accept);
717
718/*
719 * Using different timers for retransmit, delayed acks and probes
720 * We may wish use just one timer maintaining a list of expire jiffies
721 * to optimize.
722 */
723void inet_csk_init_xmit_timers(struct sock *sk,
724 void (*retransmit_handler)(struct timer_list *t),
725 void (*delack_handler)(struct timer_list *t),
726 void (*keepalive_handler)(struct timer_list *t))
727{
728 struct inet_connection_sock *icsk = inet_csk(sk);
729
730 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
731 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
732 timer_setup(&sk->sk_timer, keepalive_handler, 0);
733 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
734}
735EXPORT_SYMBOL(inet_csk_init_xmit_timers);
736
737void inet_csk_clear_xmit_timers(struct sock *sk)
738{
739 struct inet_connection_sock *icsk = inet_csk(sk);
740
741 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
742
743 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
744 sk_stop_timer(sk, &icsk->icsk_delack_timer);
745 sk_stop_timer(sk, &sk->sk_timer);
746}
747EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
748
749void inet_csk_delete_keepalive_timer(struct sock *sk)
750{
751 sk_stop_timer(sk, &sk->sk_timer);
752}
753EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
754
755void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
756{
757 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
758}
759EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
760
761struct dst_entry *inet_csk_route_req(const struct sock *sk,
762 struct flowi4 *fl4,
763 const struct request_sock *req)
764{
765 const struct inet_request_sock *ireq = inet_rsk(req);
766 struct net *net = read_pnet(&ireq->ireq_net);
767 struct ip_options_rcu *opt;
768 struct rtable *rt;
769
770 rcu_read_lock();
771 opt = rcu_dereference(ireq->ireq_opt);
772
773 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
774 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
775 sk->sk_protocol, inet_sk_flowi_flags(sk),
776 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
777 ireq->ir_loc_addr, ireq->ir_rmt_port,
778 htons(ireq->ir_num), sk->sk_uid);
779 security_req_classify_flow(req, flowi4_to_flowi_common(fl4));
780 rt = ip_route_output_flow(net, fl4, sk);
781 if (IS_ERR(rt))
782 goto no_route;
783 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
784 goto route_err;
785 rcu_read_unlock();
786 return &rt->dst;
787
788route_err:
789 ip_rt_put(rt);
790no_route:
791 rcu_read_unlock();
792 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
793 return NULL;
794}
795EXPORT_SYMBOL_GPL(inet_csk_route_req);
796
797struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
798 struct sock *newsk,
799 const struct request_sock *req)
800{
801 const struct inet_request_sock *ireq = inet_rsk(req);
802 struct net *net = read_pnet(&ireq->ireq_net);
803 struct inet_sock *newinet = inet_sk(newsk);
804 struct ip_options_rcu *opt;
805 struct flowi4 *fl4;
806 struct rtable *rt;
807
808 opt = rcu_dereference(ireq->ireq_opt);
809 fl4 = &newinet->cork.fl.u.ip4;
810
811 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
812 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
813 sk->sk_protocol, inet_sk_flowi_flags(sk),
814 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
815 ireq->ir_loc_addr, ireq->ir_rmt_port,
816 htons(ireq->ir_num), sk->sk_uid);
817 security_req_classify_flow(req, flowi4_to_flowi_common(fl4));
818 rt = ip_route_output_flow(net, fl4, sk);
819 if (IS_ERR(rt))
820 goto no_route;
821 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
822 goto route_err;
823 return &rt->dst;
824
825route_err:
826 ip_rt_put(rt);
827no_route:
828 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
829 return NULL;
830}
831EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
832
833/* Decide when to expire the request and when to resend SYN-ACK */
834static void syn_ack_recalc(struct request_sock *req,
835 const int max_syn_ack_retries,
836 const u8 rskq_defer_accept,
837 int *expire, int *resend)
838{
839 if (!rskq_defer_accept) {
840 *expire = req->num_timeout >= max_syn_ack_retries;
841 *resend = 1;
842 return;
843 }
844 *expire = req->num_timeout >= max_syn_ack_retries &&
845 (!inet_rsk(req)->acked || req->num_timeout >= rskq_defer_accept);
846 /* Do not resend while waiting for data after ACK,
847 * start to resend on end of deferring period to give
848 * last chance for data or ACK to create established socket.
849 */
850 *resend = !inet_rsk(req)->acked ||
851 req->num_timeout >= rskq_defer_accept - 1;
852}
853
854int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
855{
856 int err = req->rsk_ops->rtx_syn_ack(parent, req);
857
858 if (!err)
859 req->num_retrans++;
860 return err;
861}
862EXPORT_SYMBOL(inet_rtx_syn_ack);
863
864static struct request_sock *inet_reqsk_clone(struct request_sock *req,
865 struct sock *sk)
866{
867 struct sock *req_sk, *nreq_sk;
868 struct request_sock *nreq;
869
870 nreq = kmem_cache_alloc(req->rsk_ops->slab, GFP_ATOMIC | __GFP_NOWARN);
871 if (!nreq) {
872 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
873
874 /* paired with refcount_inc_not_zero() in reuseport_migrate_sock() */
875 sock_put(sk);
876 return NULL;
877 }
878
879 req_sk = req_to_sk(req);
880 nreq_sk = req_to_sk(nreq);
881
882 memcpy(nreq_sk, req_sk,
883 offsetof(struct sock, sk_dontcopy_begin));
884 memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end,
885 req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end));
886
887 sk_node_init(&nreq_sk->sk_node);
888 nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping;
889#ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
890 nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping;
891#endif
892 nreq_sk->sk_incoming_cpu = req_sk->sk_incoming_cpu;
893
894 nreq->rsk_listener = sk;
895
896 /* We need not acquire fastopenq->lock
897 * because the child socket is locked in inet_csk_listen_stop().
898 */
899 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(nreq)->tfo_listener)
900 rcu_assign_pointer(tcp_sk(nreq->sk)->fastopen_rsk, nreq);
901
902 return nreq;
903}
904
905static void reqsk_queue_migrated(struct request_sock_queue *queue,
906 const struct request_sock *req)
907{
908 if (req->num_timeout == 0)
909 atomic_inc(&queue->young);
910 atomic_inc(&queue->qlen);
911}
912
913static void reqsk_migrate_reset(struct request_sock *req)
914{
915 req->saved_syn = NULL;
916#if IS_ENABLED(CONFIG_IPV6)
917 inet_rsk(req)->ipv6_opt = NULL;
918 inet_rsk(req)->pktopts = NULL;
919#else
920 inet_rsk(req)->ireq_opt = NULL;
921#endif
922}
923
924/* return true if req was found in the ehash table */
925static bool reqsk_queue_unlink(struct request_sock *req)
926{
927 struct sock *sk = req_to_sk(req);
928 bool found = false;
929
930 if (sk_hashed(sk)) {
931 struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk);
932 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
933
934 spin_lock(lock);
935 found = __sk_nulls_del_node_init_rcu(sk);
936 spin_unlock(lock);
937 }
938 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
939 reqsk_put(req);
940 return found;
941}
942
943bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
944{
945 bool unlinked = reqsk_queue_unlink(req);
946
947 if (unlinked) {
948 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
949 reqsk_put(req);
950 }
951 return unlinked;
952}
953EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
954
955void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
956{
957 inet_csk_reqsk_queue_drop(sk, req);
958 reqsk_put(req);
959}
960EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
961
962static void reqsk_timer_handler(struct timer_list *t)
963{
964 struct request_sock *req = from_timer(req, t, rsk_timer);
965 struct request_sock *nreq = NULL, *oreq = req;
966 struct sock *sk_listener = req->rsk_listener;
967 struct inet_connection_sock *icsk;
968 struct request_sock_queue *queue;
969 struct net *net;
970 int max_syn_ack_retries, qlen, expire = 0, resend = 0;
971
972 if (inet_sk_state_load(sk_listener) != TCP_LISTEN) {
973 struct sock *nsk;
974
975 nsk = reuseport_migrate_sock(sk_listener, req_to_sk(req), NULL);
976 if (!nsk)
977 goto drop;
978
979 nreq = inet_reqsk_clone(req, nsk);
980 if (!nreq)
981 goto drop;
982
983 /* The new timer for the cloned req can decrease the 2
984 * by calling inet_csk_reqsk_queue_drop_and_put(), so
985 * hold another count to prevent use-after-free and
986 * call reqsk_put() just before return.
987 */
988 refcount_set(&nreq->rsk_refcnt, 2 + 1);
989 timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
990 reqsk_queue_migrated(&inet_csk(nsk)->icsk_accept_queue, req);
991
992 req = nreq;
993 sk_listener = nsk;
994 }
995
996 icsk = inet_csk(sk_listener);
997 net = sock_net(sk_listener);
998 max_syn_ack_retries = icsk->icsk_syn_retries ? :
999 READ_ONCE(net->ipv4.sysctl_tcp_synack_retries);
1000 /* Normally all the openreqs are young and become mature
1001 * (i.e. converted to established socket) for first timeout.
1002 * If synack was not acknowledged for 1 second, it means
1003 * one of the following things: synack was lost, ack was lost,
1004 * rtt is high or nobody planned to ack (i.e. synflood).
1005 * When server is a bit loaded, queue is populated with old
1006 * open requests, reducing effective size of queue.
1007 * When server is well loaded, queue size reduces to zero
1008 * after several minutes of work. It is not synflood,
1009 * it is normal operation. The solution is pruning
1010 * too old entries overriding normal timeout, when
1011 * situation becomes dangerous.
1012 *
1013 * Essentially, we reserve half of room for young
1014 * embrions; and abort old ones without pity, if old
1015 * ones are about to clog our table.
1016 */
1017 queue = &icsk->icsk_accept_queue;
1018 qlen = reqsk_queue_len(queue);
1019 if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {
1020 int young = reqsk_queue_len_young(queue) << 1;
1021
1022 while (max_syn_ack_retries > 2) {
1023 if (qlen < young)
1024 break;
1025 max_syn_ack_retries--;
1026 young <<= 1;
1027 }
1028 }
1029 syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept),
1030 &expire, &resend);
1031 req->rsk_ops->syn_ack_timeout(req);
1032 if (!expire &&
1033 (!resend ||
1034 !inet_rtx_syn_ack(sk_listener, req) ||
1035 inet_rsk(req)->acked)) {
1036 if (req->num_timeout++ == 0)
1037 atomic_dec(&queue->young);
1038 mod_timer(&req->rsk_timer, jiffies + reqsk_timeout(req, TCP_RTO_MAX));
1039
1040 if (!nreq)
1041 return;
1042
1043 if (!inet_ehash_insert(req_to_sk(nreq), req_to_sk(oreq), NULL)) {
1044 /* delete timer */
1045 inet_csk_reqsk_queue_drop(sk_listener, nreq);
1046 goto no_ownership;
1047 }
1048
1049 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQSUCCESS);
1050 reqsk_migrate_reset(oreq);
1051 reqsk_queue_removed(&inet_csk(oreq->rsk_listener)->icsk_accept_queue, oreq);
1052 reqsk_put(oreq);
1053
1054 reqsk_put(nreq);
1055 return;
1056 }
1057
1058 /* Even if we can clone the req, we may need not retransmit any more
1059 * SYN+ACKs (nreq->num_timeout > max_syn_ack_retries, etc), or another
1060 * CPU may win the "own_req" race so that inet_ehash_insert() fails.
1061 */
1062 if (nreq) {
1063 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQFAILURE);
1064no_ownership:
1065 reqsk_migrate_reset(nreq);
1066 reqsk_queue_removed(queue, nreq);
1067 __reqsk_free(nreq);
1068 }
1069
1070drop:
1071 inet_csk_reqsk_queue_drop_and_put(oreq->rsk_listener, oreq);
1072}
1073
1074static void reqsk_queue_hash_req(struct request_sock *req,
1075 unsigned long timeout)
1076{
1077 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
1078 mod_timer(&req->rsk_timer, jiffies + timeout);
1079
1080 inet_ehash_insert(req_to_sk(req), NULL, NULL);
1081 /* before letting lookups find us, make sure all req fields
1082 * are committed to memory and refcnt initialized.
1083 */
1084 smp_wmb();
1085 refcount_set(&req->rsk_refcnt, 2 + 1);
1086}
1087
1088void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
1089 unsigned long timeout)
1090{
1091 reqsk_queue_hash_req(req, timeout);
1092 inet_csk_reqsk_queue_added(sk);
1093}
1094EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
1095
1096static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk,
1097 const gfp_t priority)
1098{
1099 struct inet_connection_sock *icsk = inet_csk(newsk);
1100
1101 if (!icsk->icsk_ulp_ops)
1102 return;
1103
1104 if (icsk->icsk_ulp_ops->clone)
1105 icsk->icsk_ulp_ops->clone(req, newsk, priority);
1106}
1107
1108/**
1109 * inet_csk_clone_lock - clone an inet socket, and lock its clone
1110 * @sk: the socket to clone
1111 * @req: request_sock
1112 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
1113 *
1114 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
1115 */
1116struct sock *inet_csk_clone_lock(const struct sock *sk,
1117 const struct request_sock *req,
1118 const gfp_t priority)
1119{
1120 struct sock *newsk = sk_clone_lock(sk, priority);
1121
1122 if (newsk) {
1123 struct inet_connection_sock *newicsk = inet_csk(newsk);
1124
1125 inet_sk_set_state(newsk, TCP_SYN_RECV);
1126 newicsk->icsk_bind_hash = NULL;
1127 newicsk->icsk_bind2_hash = NULL;
1128
1129 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
1130 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
1131 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
1132
1133 /* listeners have SOCK_RCU_FREE, not the children */
1134 sock_reset_flag(newsk, SOCK_RCU_FREE);
1135
1136 inet_sk(newsk)->mc_list = NULL;
1137
1138 newsk->sk_mark = inet_rsk(req)->ir_mark;
1139 atomic64_set(&newsk->sk_cookie,
1140 atomic64_read(&inet_rsk(req)->ir_cookie));
1141
1142 newicsk->icsk_retransmits = 0;
1143 newicsk->icsk_backoff = 0;
1144 newicsk->icsk_probes_out = 0;
1145 newicsk->icsk_probes_tstamp = 0;
1146
1147 /* Deinitialize accept_queue to trap illegal accesses. */
1148 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
1149
1150 inet_clone_ulp(req, newsk, priority);
1151
1152 security_inet_csk_clone(newsk, req);
1153 }
1154 return newsk;
1155}
1156EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
1157
1158/*
1159 * At this point, there should be no process reference to this
1160 * socket, and thus no user references at all. Therefore we
1161 * can assume the socket waitqueue is inactive and nobody will
1162 * try to jump onto it.
1163 */
1164void inet_csk_destroy_sock(struct sock *sk)
1165{
1166 WARN_ON(sk->sk_state != TCP_CLOSE);
1167 WARN_ON(!sock_flag(sk, SOCK_DEAD));
1168
1169 /* It cannot be in hash table! */
1170 WARN_ON(!sk_unhashed(sk));
1171
1172 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
1173 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
1174
1175 sk->sk_prot->destroy(sk);
1176
1177 sk_stream_kill_queues(sk);
1178
1179 xfrm_sk_free_policy(sk);
1180
1181 sk_refcnt_debug_release(sk);
1182
1183 this_cpu_dec(*sk->sk_prot->orphan_count);
1184
1185 sock_put(sk);
1186}
1187EXPORT_SYMBOL(inet_csk_destroy_sock);
1188
1189/* This function allows to force a closure of a socket after the call to
1190 * tcp/dccp_create_openreq_child().
1191 */
1192void inet_csk_prepare_forced_close(struct sock *sk)
1193 __releases(&sk->sk_lock.slock)
1194{
1195 /* sk_clone_lock locked the socket and set refcnt to 2 */
1196 bh_unlock_sock(sk);
1197 sock_put(sk);
1198 inet_csk_prepare_for_destroy_sock(sk);
1199 inet_sk(sk)->inet_num = 0;
1200}
1201EXPORT_SYMBOL(inet_csk_prepare_forced_close);
1202
1203static int inet_ulp_can_listen(const struct sock *sk)
1204{
1205 const struct inet_connection_sock *icsk = inet_csk(sk);
1206
1207 if (icsk->icsk_ulp_ops && !icsk->icsk_ulp_ops->clone)
1208 return -EINVAL;
1209
1210 return 0;
1211}
1212
1213int inet_csk_listen_start(struct sock *sk)
1214{
1215 struct inet_connection_sock *icsk = inet_csk(sk);
1216 struct inet_sock *inet = inet_sk(sk);
1217 int err;
1218
1219 err = inet_ulp_can_listen(sk);
1220 if (unlikely(err))
1221 return err;
1222
1223 reqsk_queue_alloc(&icsk->icsk_accept_queue);
1224
1225 sk->sk_ack_backlog = 0;
1226 inet_csk_delack_init(sk);
1227
1228 /* There is race window here: we announce ourselves listening,
1229 * but this transition is still not validated by get_port().
1230 * It is OK, because this socket enters to hash table only
1231 * after validation is complete.
1232 */
1233 inet_sk_state_store(sk, TCP_LISTEN);
1234 err = sk->sk_prot->get_port(sk, inet->inet_num);
1235 if (!err) {
1236 inet->inet_sport = htons(inet->inet_num);
1237
1238 sk_dst_reset(sk);
1239 err = sk->sk_prot->hash(sk);
1240
1241 if (likely(!err))
1242 return 0;
1243 }
1244
1245 inet_sk_set_state(sk, TCP_CLOSE);
1246 return err;
1247}
1248EXPORT_SYMBOL_GPL(inet_csk_listen_start);
1249
1250static void inet_child_forget(struct sock *sk, struct request_sock *req,
1251 struct sock *child)
1252{
1253 sk->sk_prot->disconnect(child, O_NONBLOCK);
1254
1255 sock_orphan(child);
1256
1257 this_cpu_inc(*sk->sk_prot->orphan_count);
1258
1259 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
1260 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req);
1261 BUG_ON(sk != req->rsk_listener);
1262
1263 /* Paranoid, to prevent race condition if
1264 * an inbound pkt destined for child is
1265 * blocked by sock lock in tcp_v4_rcv().
1266 * Also to satisfy an assertion in
1267 * tcp_v4_destroy_sock().
1268 */
1269 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL);
1270 }
1271 inet_csk_destroy_sock(child);
1272}
1273
1274struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
1275 struct request_sock *req,
1276 struct sock *child)
1277{
1278 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
1279
1280 spin_lock(&queue->rskq_lock);
1281 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1282 inet_child_forget(sk, req, child);
1283 child = NULL;
1284 } else {
1285 req->sk = child;
1286 req->dl_next = NULL;
1287 if (queue->rskq_accept_head == NULL)
1288 WRITE_ONCE(queue->rskq_accept_head, req);
1289 else
1290 queue->rskq_accept_tail->dl_next = req;
1291 queue->rskq_accept_tail = req;
1292 sk_acceptq_added(sk);
1293 }
1294 spin_unlock(&queue->rskq_lock);
1295 return child;
1296}
1297EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
1298
1299struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
1300 struct request_sock *req, bool own_req)
1301{
1302 if (own_req) {
1303 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
1304 reqsk_queue_removed(&inet_csk(req->rsk_listener)->icsk_accept_queue, req);
1305
1306 if (sk != req->rsk_listener) {
1307 /* another listening sk has been selected,
1308 * migrate the req to it.
1309 */
1310 struct request_sock *nreq;
1311
1312 /* hold a refcnt for the nreq->rsk_listener
1313 * which is assigned in inet_reqsk_clone()
1314 */
1315 sock_hold(sk);
1316 nreq = inet_reqsk_clone(req, sk);
1317 if (!nreq) {
1318 inet_child_forget(sk, req, child);
1319 goto child_put;
1320 }
1321
1322 refcount_set(&nreq->rsk_refcnt, 1);
1323 if (inet_csk_reqsk_queue_add(sk, nreq, child)) {
1324 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQSUCCESS);
1325 reqsk_migrate_reset(req);
1326 reqsk_put(req);
1327 return child;
1328 }
1329
1330 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
1331 reqsk_migrate_reset(nreq);
1332 __reqsk_free(nreq);
1333 } else if (inet_csk_reqsk_queue_add(sk, req, child)) {
1334 return child;
1335 }
1336 }
1337 /* Too bad, another child took ownership of the request, undo. */
1338child_put:
1339 bh_unlock_sock(child);
1340 sock_put(child);
1341 return NULL;
1342}
1343EXPORT_SYMBOL(inet_csk_complete_hashdance);
1344
1345/*
1346 * This routine closes sockets which have been at least partially
1347 * opened, but not yet accepted.
1348 */
1349void inet_csk_listen_stop(struct sock *sk)
1350{
1351 struct inet_connection_sock *icsk = inet_csk(sk);
1352 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
1353 struct request_sock *next, *req;
1354
1355 /* Following specs, it would be better either to send FIN
1356 * (and enter FIN-WAIT-1, it is normal close)
1357 * or to send active reset (abort).
1358 * Certainly, it is pretty dangerous while synflood, but it is
1359 * bad justification for our negligence 8)
1360 * To be honest, we are not able to make either
1361 * of the variants now. --ANK
1362 */
1363 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
1364 struct sock *child = req->sk, *nsk;
1365 struct request_sock *nreq;
1366
1367 local_bh_disable();
1368 bh_lock_sock(child);
1369 WARN_ON(sock_owned_by_user(child));
1370 sock_hold(child);
1371
1372 nsk = reuseport_migrate_sock(sk, child, NULL);
1373 if (nsk) {
1374 nreq = inet_reqsk_clone(req, nsk);
1375 if (nreq) {
1376 refcount_set(&nreq->rsk_refcnt, 1);
1377
1378 if (inet_csk_reqsk_queue_add(nsk, nreq, child)) {
1379 __NET_INC_STATS(sock_net(nsk),
1380 LINUX_MIB_TCPMIGRATEREQSUCCESS);
1381 reqsk_migrate_reset(req);
1382 } else {
1383 __NET_INC_STATS(sock_net(nsk),
1384 LINUX_MIB_TCPMIGRATEREQFAILURE);
1385 reqsk_migrate_reset(nreq);
1386 __reqsk_free(nreq);
1387 }
1388
1389 /* inet_csk_reqsk_queue_add() has already
1390 * called inet_child_forget() on failure case.
1391 */
1392 goto skip_child_forget;
1393 }
1394 }
1395
1396 inet_child_forget(sk, req, child);
1397skip_child_forget:
1398 reqsk_put(req);
1399 bh_unlock_sock(child);
1400 local_bh_enable();
1401 sock_put(child);
1402
1403 cond_resched();
1404 }
1405 if (queue->fastopenq.rskq_rst_head) {
1406 /* Free all the reqs queued in rskq_rst_head. */
1407 spin_lock_bh(&queue->fastopenq.lock);
1408 req = queue->fastopenq.rskq_rst_head;
1409 queue->fastopenq.rskq_rst_head = NULL;
1410 spin_unlock_bh(&queue->fastopenq.lock);
1411 while (req != NULL) {
1412 next = req->dl_next;
1413 reqsk_put(req);
1414 req = next;
1415 }
1416 }
1417 WARN_ON_ONCE(sk->sk_ack_backlog);
1418}
1419EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1420
1421void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1422{
1423 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1424 const struct inet_sock *inet = inet_sk(sk);
1425
1426 sin->sin_family = AF_INET;
1427 sin->sin_addr.s_addr = inet->inet_daddr;
1428 sin->sin_port = inet->inet_dport;
1429}
1430EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1431
1432static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1433{
1434 const struct inet_sock *inet = inet_sk(sk);
1435 const struct ip_options_rcu *inet_opt;
1436 __be32 daddr = inet->inet_daddr;
1437 struct flowi4 *fl4;
1438 struct rtable *rt;
1439
1440 rcu_read_lock();
1441 inet_opt = rcu_dereference(inet->inet_opt);
1442 if (inet_opt && inet_opt->opt.srr)
1443 daddr = inet_opt->opt.faddr;
1444 fl4 = &fl->u.ip4;
1445 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
1446 inet->inet_saddr, inet->inet_dport,
1447 inet->inet_sport, sk->sk_protocol,
1448 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
1449 if (IS_ERR(rt))
1450 rt = NULL;
1451 if (rt)
1452 sk_setup_caps(sk, &rt->dst);
1453 rcu_read_unlock();
1454
1455 return &rt->dst;
1456}
1457
1458struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1459{
1460 struct dst_entry *dst = __sk_dst_check(sk, 0);
1461 struct inet_sock *inet = inet_sk(sk);
1462
1463 if (!dst) {
1464 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1465 if (!dst)
1466 goto out;
1467 }
1468 dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
1469
1470 dst = __sk_dst_check(sk, 0);
1471 if (!dst)
1472 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1473out:
1474 return dst;
1475}
1476EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);