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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/*
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
29#ifdef INET_CSK_DEBUG
30const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
31EXPORT_SYMBOL(inet_csk_timer_bug_msg);
32#endif
33
34void inet_get_local_port_range(struct net *net, int *low, int *high)
35{
36 unsigned int seq;
37
38 do {
39 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
40
41 *low = net->ipv4.ip_local_ports.range[0];
42 *high = net->ipv4.ip_local_ports.range[1];
43 } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
44}
45EXPORT_SYMBOL(inet_get_local_port_range);
46
47int inet_csk_bind_conflict(const struct sock *sk,
48 const struct inet_bind_bucket *tb, bool relax)
49{
50 struct sock *sk2;
51 int reuse = sk->sk_reuse;
52 int reuseport = sk->sk_reuseport;
53 kuid_t uid = sock_i_uid((struct sock *)sk);
54
55 /*
56 * Unlike other sk lookup places we do not check
57 * for sk_net here, since _all_ the socks listed
58 * in tb->owners list belong to the same net - the
59 * one this bucket belongs to.
60 */
61
62 sk_for_each_bound(sk2, &tb->owners) {
63 if (sk != sk2 &&
64 !inet_v6_ipv6only(sk2) &&
65 (!sk->sk_bound_dev_if ||
66 !sk2->sk_bound_dev_if ||
67 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
68 if ((!reuse || !sk2->sk_reuse ||
69 sk2->sk_state == TCP_LISTEN) &&
70 (!reuseport || !sk2->sk_reuseport ||
71 rcu_access_pointer(sk->sk_reuseport_cb) ||
72 (sk2->sk_state != TCP_TIME_WAIT &&
73 !uid_eq(uid, sock_i_uid(sk2))))) {
74
75 if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr ||
76 sk2->sk_rcv_saddr == sk->sk_rcv_saddr)
77 break;
78 }
79 if (!relax && reuse && sk2->sk_reuse &&
80 sk2->sk_state != TCP_LISTEN) {
81
82 if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr ||
83 sk2->sk_rcv_saddr == sk->sk_rcv_saddr)
84 break;
85 }
86 }
87 }
88 return sk2 != NULL;
89}
90EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
91
92/* Obtain a reference to a local port for the given sock,
93 * if snum is zero it means select any available local port.
94 * We try to allocate an odd port (and leave even ports for connect())
95 */
96int inet_csk_get_port(struct sock *sk, unsigned short snum)
97{
98 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
99 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
100 int ret = 1, attempts = 5, port = snum;
101 int smallest_size = -1, smallest_port;
102 struct inet_bind_hashbucket *head;
103 struct net *net = sock_net(sk);
104 int i, low, high, attempt_half;
105 struct inet_bind_bucket *tb;
106 kuid_t uid = sock_i_uid(sk);
107 u32 remaining, offset;
108
109 if (port) {
110have_port:
111 head = &hinfo->bhash[inet_bhashfn(net, port,
112 hinfo->bhash_size)];
113 spin_lock_bh(&head->lock);
114 inet_bind_bucket_for_each(tb, &head->chain)
115 if (net_eq(ib_net(tb), net) && tb->port == port)
116 goto tb_found;
117
118 goto tb_not_found;
119 }
120again:
121 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
122other_half_scan:
123 inet_get_local_port_range(net, &low, &high);
124 high++; /* [32768, 60999] -> [32768, 61000[ */
125 if (high - low < 4)
126 attempt_half = 0;
127 if (attempt_half) {
128 int half = low + (((high - low) >> 2) << 1);
129
130 if (attempt_half == 1)
131 high = half;
132 else
133 low = half;
134 }
135 remaining = high - low;
136 if (likely(remaining > 1))
137 remaining &= ~1U;
138
139 offset = prandom_u32() % remaining;
140 /* __inet_hash_connect() favors ports having @low parity
141 * We do the opposite to not pollute connect() users.
142 */
143 offset |= 1U;
144 smallest_size = -1;
145 smallest_port = low; /* avoid compiler warning */
146
147other_parity_scan:
148 port = low + offset;
149 for (i = 0; i < remaining; i += 2, port += 2) {
150 if (unlikely(port >= high))
151 port -= remaining;
152 if (inet_is_local_reserved_port(net, port))
153 continue;
154 head = &hinfo->bhash[inet_bhashfn(net, port,
155 hinfo->bhash_size)];
156 spin_lock_bh(&head->lock);
157 inet_bind_bucket_for_each(tb, &head->chain)
158 if (net_eq(ib_net(tb), net) && tb->port == port) {
159 if (((tb->fastreuse > 0 && reuse) ||
160 (tb->fastreuseport > 0 &&
161 sk->sk_reuseport &&
162 !rcu_access_pointer(sk->sk_reuseport_cb) &&
163 uid_eq(tb->fastuid, uid))) &&
164 (tb->num_owners < smallest_size || smallest_size == -1)) {
165 smallest_size = tb->num_owners;
166 smallest_port = port;
167 }
168 if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false))
169 goto tb_found;
170 goto next_port;
171 }
172 goto tb_not_found;
173next_port:
174 spin_unlock_bh(&head->lock);
175 cond_resched();
176 }
177
178 if (smallest_size != -1) {
179 port = smallest_port;
180 goto have_port;
181 }
182 offset--;
183 if (!(offset & 1))
184 goto other_parity_scan;
185
186 if (attempt_half == 1) {
187 /* OK we now try the upper half of the range */
188 attempt_half = 2;
189 goto other_half_scan;
190 }
191 return ret;
192
193tb_not_found:
194 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
195 net, head, port);
196 if (!tb)
197 goto fail_unlock;
198tb_found:
199 if (!hlist_empty(&tb->owners)) {
200 if (sk->sk_reuse == SK_FORCE_REUSE)
201 goto success;
202
203 if (((tb->fastreuse > 0 && reuse) ||
204 (tb->fastreuseport > 0 &&
205 !rcu_access_pointer(sk->sk_reuseport_cb) &&
206 sk->sk_reuseport && uid_eq(tb->fastuid, uid))) &&
207 smallest_size == -1)
208 goto success;
209 if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) {
210 if ((reuse ||
211 (tb->fastreuseport > 0 &&
212 sk->sk_reuseport &&
213 !rcu_access_pointer(sk->sk_reuseport_cb) &&
214 uid_eq(tb->fastuid, uid))) &&
215 smallest_size != -1 && --attempts >= 0) {
216 spin_unlock_bh(&head->lock);
217 goto again;
218 }
219 goto fail_unlock;
220 }
221 if (!reuse)
222 tb->fastreuse = 0;
223 if (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid))
224 tb->fastreuseport = 0;
225 } else {
226 tb->fastreuse = reuse;
227 if (sk->sk_reuseport) {
228 tb->fastreuseport = 1;
229 tb->fastuid = uid;
230 } else {
231 tb->fastreuseport = 0;
232 }
233 }
234success:
235 if (!inet_csk(sk)->icsk_bind_hash)
236 inet_bind_hash(sk, tb, port);
237 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
238 ret = 0;
239
240fail_unlock:
241 spin_unlock_bh(&head->lock);
242 return ret;
243}
244EXPORT_SYMBOL_GPL(inet_csk_get_port);
245
246/*
247 * Wait for an incoming connection, avoid race conditions. This must be called
248 * with the socket locked.
249 */
250static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
251{
252 struct inet_connection_sock *icsk = inet_csk(sk);
253 DEFINE_WAIT(wait);
254 int err;
255
256 /*
257 * True wake-one mechanism for incoming connections: only
258 * one process gets woken up, not the 'whole herd'.
259 * Since we do not 'race & poll' for established sockets
260 * anymore, the common case will execute the loop only once.
261 *
262 * Subtle issue: "add_wait_queue_exclusive()" will be added
263 * after any current non-exclusive waiters, and we know that
264 * it will always _stay_ after any new non-exclusive waiters
265 * because all non-exclusive waiters are added at the
266 * beginning of the wait-queue. As such, it's ok to "drop"
267 * our exclusiveness temporarily when we get woken up without
268 * having to remove and re-insert us on the wait queue.
269 */
270 for (;;) {
271 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
272 TASK_INTERRUPTIBLE);
273 release_sock(sk);
274 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
275 timeo = schedule_timeout(timeo);
276 sched_annotate_sleep();
277 lock_sock(sk);
278 err = 0;
279 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
280 break;
281 err = -EINVAL;
282 if (sk->sk_state != TCP_LISTEN)
283 break;
284 err = sock_intr_errno(timeo);
285 if (signal_pending(current))
286 break;
287 err = -EAGAIN;
288 if (!timeo)
289 break;
290 }
291 finish_wait(sk_sleep(sk), &wait);
292 return err;
293}
294
295/*
296 * This will accept the next outstanding connection.
297 */
298struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
299{
300 struct inet_connection_sock *icsk = inet_csk(sk);
301 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
302 struct request_sock *req;
303 struct sock *newsk;
304 int error;
305
306 lock_sock(sk);
307
308 /* We need to make sure that this socket is listening,
309 * and that it has something pending.
310 */
311 error = -EINVAL;
312 if (sk->sk_state != TCP_LISTEN)
313 goto out_err;
314
315 /* Find already established connection */
316 if (reqsk_queue_empty(queue)) {
317 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
318
319 /* If this is a non blocking socket don't sleep */
320 error = -EAGAIN;
321 if (!timeo)
322 goto out_err;
323
324 error = inet_csk_wait_for_connect(sk, timeo);
325 if (error)
326 goto out_err;
327 }
328 req = reqsk_queue_remove(queue, sk);
329 newsk = req->sk;
330
331 if (sk->sk_protocol == IPPROTO_TCP &&
332 tcp_rsk(req)->tfo_listener) {
333 spin_lock_bh(&queue->fastopenq.lock);
334 if (tcp_rsk(req)->tfo_listener) {
335 /* We are still waiting for the final ACK from 3WHS
336 * so can't free req now. Instead, we set req->sk to
337 * NULL to signify that the child socket is taken
338 * so reqsk_fastopen_remove() will free the req
339 * when 3WHS finishes (or is aborted).
340 */
341 req->sk = NULL;
342 req = NULL;
343 }
344 spin_unlock_bh(&queue->fastopenq.lock);
345 }
346out:
347 release_sock(sk);
348 if (req)
349 reqsk_put(req);
350 return newsk;
351out_err:
352 newsk = NULL;
353 req = NULL;
354 *err = error;
355 goto out;
356}
357EXPORT_SYMBOL(inet_csk_accept);
358
359/*
360 * Using different timers for retransmit, delayed acks and probes
361 * We may wish use just one timer maintaining a list of expire jiffies
362 * to optimize.
363 */
364void inet_csk_init_xmit_timers(struct sock *sk,
365 void (*retransmit_handler)(unsigned long),
366 void (*delack_handler)(unsigned long),
367 void (*keepalive_handler)(unsigned long))
368{
369 struct inet_connection_sock *icsk = inet_csk(sk);
370
371 setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
372 (unsigned long)sk);
373 setup_timer(&icsk->icsk_delack_timer, delack_handler,
374 (unsigned long)sk);
375 setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
376 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
377}
378EXPORT_SYMBOL(inet_csk_init_xmit_timers);
379
380void inet_csk_clear_xmit_timers(struct sock *sk)
381{
382 struct inet_connection_sock *icsk = inet_csk(sk);
383
384 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
385
386 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
387 sk_stop_timer(sk, &icsk->icsk_delack_timer);
388 sk_stop_timer(sk, &sk->sk_timer);
389}
390EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
391
392void inet_csk_delete_keepalive_timer(struct sock *sk)
393{
394 sk_stop_timer(sk, &sk->sk_timer);
395}
396EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
397
398void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
399{
400 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
401}
402EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
403
404struct dst_entry *inet_csk_route_req(const struct sock *sk,
405 struct flowi4 *fl4,
406 const struct request_sock *req)
407{
408 const struct inet_request_sock *ireq = inet_rsk(req);
409 struct net *net = read_pnet(&ireq->ireq_net);
410 struct ip_options_rcu *opt = ireq->opt;
411 struct rtable *rt;
412
413 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
414 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
415 sk->sk_protocol, inet_sk_flowi_flags(sk),
416 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
417 ireq->ir_loc_addr, ireq->ir_rmt_port,
418 htons(ireq->ir_num));
419 security_req_classify_flow(req, flowi4_to_flowi(fl4));
420 rt = ip_route_output_flow(net, fl4, sk);
421 if (IS_ERR(rt))
422 goto no_route;
423 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
424 goto route_err;
425 return &rt->dst;
426
427route_err:
428 ip_rt_put(rt);
429no_route:
430 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
431 return NULL;
432}
433EXPORT_SYMBOL_GPL(inet_csk_route_req);
434
435struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
436 struct sock *newsk,
437 const struct request_sock *req)
438{
439 const struct inet_request_sock *ireq = inet_rsk(req);
440 struct net *net = read_pnet(&ireq->ireq_net);
441 struct inet_sock *newinet = inet_sk(newsk);
442 struct ip_options_rcu *opt;
443 struct flowi4 *fl4;
444 struct rtable *rt;
445
446 fl4 = &newinet->cork.fl.u.ip4;
447
448 rcu_read_lock();
449 opt = rcu_dereference(newinet->inet_opt);
450 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
451 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
452 sk->sk_protocol, inet_sk_flowi_flags(sk),
453 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
454 ireq->ir_loc_addr, ireq->ir_rmt_port,
455 htons(ireq->ir_num));
456 security_req_classify_flow(req, flowi4_to_flowi(fl4));
457 rt = ip_route_output_flow(net, fl4, sk);
458 if (IS_ERR(rt))
459 goto no_route;
460 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
461 goto route_err;
462 rcu_read_unlock();
463 return &rt->dst;
464
465route_err:
466 ip_rt_put(rt);
467no_route:
468 rcu_read_unlock();
469 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
470 return NULL;
471}
472EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
473
474#if IS_ENABLED(CONFIG_IPV6)
475#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
476#else
477#define AF_INET_FAMILY(fam) true
478#endif
479
480/* Decide when to expire the request and when to resend SYN-ACK */
481static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
482 const int max_retries,
483 const u8 rskq_defer_accept,
484 int *expire, int *resend)
485{
486 if (!rskq_defer_accept) {
487 *expire = req->num_timeout >= thresh;
488 *resend = 1;
489 return;
490 }
491 *expire = req->num_timeout >= thresh &&
492 (!inet_rsk(req)->acked || req->num_timeout >= max_retries);
493 /*
494 * Do not resend while waiting for data after ACK,
495 * start to resend on end of deferring period to give
496 * last chance for data or ACK to create established socket.
497 */
498 *resend = !inet_rsk(req)->acked ||
499 req->num_timeout >= rskq_defer_accept - 1;
500}
501
502int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
503{
504 int err = req->rsk_ops->rtx_syn_ack(parent, req);
505
506 if (!err)
507 req->num_retrans++;
508 return err;
509}
510EXPORT_SYMBOL(inet_rtx_syn_ack);
511
512/* return true if req was found in the ehash table */
513static bool reqsk_queue_unlink(struct request_sock_queue *queue,
514 struct request_sock *req)
515{
516 struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo;
517 bool found = false;
518
519 if (sk_hashed(req_to_sk(req))) {
520 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
521
522 spin_lock(lock);
523 found = __sk_nulls_del_node_init_rcu(req_to_sk(req));
524 spin_unlock(lock);
525 }
526 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
527 reqsk_put(req);
528 return found;
529}
530
531void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
532{
533 if (reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req)) {
534 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
535 reqsk_put(req);
536 }
537}
538EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
539
540void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
541{
542 inet_csk_reqsk_queue_drop(sk, req);
543 reqsk_put(req);
544}
545EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
546
547static void reqsk_timer_handler(unsigned long data)
548{
549 struct request_sock *req = (struct request_sock *)data;
550 struct sock *sk_listener = req->rsk_listener;
551 struct net *net = sock_net(sk_listener);
552 struct inet_connection_sock *icsk = inet_csk(sk_listener);
553 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
554 int qlen, expire = 0, resend = 0;
555 int max_retries, thresh;
556 u8 defer_accept;
557
558 if (sk_state_load(sk_listener) != TCP_LISTEN)
559 goto drop;
560
561 max_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries;
562 thresh = max_retries;
563 /* Normally all the openreqs are young and become mature
564 * (i.e. converted to established socket) for first timeout.
565 * If synack was not acknowledged for 1 second, it means
566 * one of the following things: synack was lost, ack was lost,
567 * rtt is high or nobody planned to ack (i.e. synflood).
568 * When server is a bit loaded, queue is populated with old
569 * open requests, reducing effective size of queue.
570 * When server is well loaded, queue size reduces to zero
571 * after several minutes of work. It is not synflood,
572 * it is normal operation. The solution is pruning
573 * too old entries overriding normal timeout, when
574 * situation becomes dangerous.
575 *
576 * Essentially, we reserve half of room for young
577 * embrions; and abort old ones without pity, if old
578 * ones are about to clog our table.
579 */
580 qlen = reqsk_queue_len(queue);
581 if ((qlen << 1) > max(8U, sk_listener->sk_max_ack_backlog)) {
582 int young = reqsk_queue_len_young(queue) << 1;
583
584 while (thresh > 2) {
585 if (qlen < young)
586 break;
587 thresh--;
588 young <<= 1;
589 }
590 }
591 defer_accept = READ_ONCE(queue->rskq_defer_accept);
592 if (defer_accept)
593 max_retries = defer_accept;
594 syn_ack_recalc(req, thresh, max_retries, defer_accept,
595 &expire, &resend);
596 req->rsk_ops->syn_ack_timeout(req);
597 if (!expire &&
598 (!resend ||
599 !inet_rtx_syn_ack(sk_listener, req) ||
600 inet_rsk(req)->acked)) {
601 unsigned long timeo;
602
603 if (req->num_timeout++ == 0)
604 atomic_dec(&queue->young);
605 timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
606 mod_timer_pinned(&req->rsk_timer, jiffies + timeo);
607 return;
608 }
609drop:
610 inet_csk_reqsk_queue_drop_and_put(sk_listener, req);
611}
612
613static void reqsk_queue_hash_req(struct request_sock *req,
614 unsigned long timeout)
615{
616 req->num_retrans = 0;
617 req->num_timeout = 0;
618 req->sk = NULL;
619
620 setup_timer(&req->rsk_timer, reqsk_timer_handler, (unsigned long)req);
621 mod_timer_pinned(&req->rsk_timer, jiffies + timeout);
622
623 inet_ehash_insert(req_to_sk(req), NULL);
624 /* before letting lookups find us, make sure all req fields
625 * are committed to memory and refcnt initialized.
626 */
627 smp_wmb();
628 atomic_set(&req->rsk_refcnt, 2 + 1);
629}
630
631void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
632 unsigned long timeout)
633{
634 reqsk_queue_hash_req(req, timeout);
635 inet_csk_reqsk_queue_added(sk);
636}
637EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
638
639/**
640 * inet_csk_clone_lock - clone an inet socket, and lock its clone
641 * @sk: the socket to clone
642 * @req: request_sock
643 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
644 *
645 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
646 */
647struct sock *inet_csk_clone_lock(const struct sock *sk,
648 const struct request_sock *req,
649 const gfp_t priority)
650{
651 struct sock *newsk = sk_clone_lock(sk, priority);
652
653 if (newsk) {
654 struct inet_connection_sock *newicsk = inet_csk(newsk);
655
656 newsk->sk_state = TCP_SYN_RECV;
657 newicsk->icsk_bind_hash = NULL;
658
659 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
660 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
661 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
662 newsk->sk_write_space = sk_stream_write_space;
663
664 newsk->sk_mark = inet_rsk(req)->ir_mark;
665 atomic64_set(&newsk->sk_cookie,
666 atomic64_read(&inet_rsk(req)->ir_cookie));
667
668 newicsk->icsk_retransmits = 0;
669 newicsk->icsk_backoff = 0;
670 newicsk->icsk_probes_out = 0;
671
672 /* Deinitialize accept_queue to trap illegal accesses. */
673 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
674
675 security_inet_csk_clone(newsk, req);
676 }
677 return newsk;
678}
679EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
680
681/*
682 * At this point, there should be no process reference to this
683 * socket, and thus no user references at all. Therefore we
684 * can assume the socket waitqueue is inactive and nobody will
685 * try to jump onto it.
686 */
687void inet_csk_destroy_sock(struct sock *sk)
688{
689 WARN_ON(sk->sk_state != TCP_CLOSE);
690 WARN_ON(!sock_flag(sk, SOCK_DEAD));
691
692 /* It cannot be in hash table! */
693 WARN_ON(!sk_unhashed(sk));
694
695 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
696 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
697
698 sk->sk_prot->destroy(sk);
699
700 sk_stream_kill_queues(sk);
701
702 xfrm_sk_free_policy(sk);
703
704 sk_refcnt_debug_release(sk);
705
706 percpu_counter_dec(sk->sk_prot->orphan_count);
707 sock_put(sk);
708}
709EXPORT_SYMBOL(inet_csk_destroy_sock);
710
711/* This function allows to force a closure of a socket after the call to
712 * tcp/dccp_create_openreq_child().
713 */
714void inet_csk_prepare_forced_close(struct sock *sk)
715 __releases(&sk->sk_lock.slock)
716{
717 /* sk_clone_lock locked the socket and set refcnt to 2 */
718 bh_unlock_sock(sk);
719 sock_put(sk);
720
721 /* The below has to be done to allow calling inet_csk_destroy_sock */
722 sock_set_flag(sk, SOCK_DEAD);
723 percpu_counter_inc(sk->sk_prot->orphan_count);
724 inet_sk(sk)->inet_num = 0;
725}
726EXPORT_SYMBOL(inet_csk_prepare_forced_close);
727
728int inet_csk_listen_start(struct sock *sk, int backlog)
729{
730 struct inet_connection_sock *icsk = inet_csk(sk);
731 struct inet_sock *inet = inet_sk(sk);
732 int err = -EADDRINUSE;
733
734 reqsk_queue_alloc(&icsk->icsk_accept_queue);
735
736 sk->sk_max_ack_backlog = backlog;
737 sk->sk_ack_backlog = 0;
738 inet_csk_delack_init(sk);
739
740 /* There is race window here: we announce ourselves listening,
741 * but this transition is still not validated by get_port().
742 * It is OK, because this socket enters to hash table only
743 * after validation is complete.
744 */
745 sk_state_store(sk, TCP_LISTEN);
746 if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
747 inet->inet_sport = htons(inet->inet_num);
748
749 sk_dst_reset(sk);
750 err = sk->sk_prot->hash(sk);
751
752 if (likely(!err))
753 return 0;
754 }
755
756 sk->sk_state = TCP_CLOSE;
757 return err;
758}
759EXPORT_SYMBOL_GPL(inet_csk_listen_start);
760
761static void inet_child_forget(struct sock *sk, struct request_sock *req,
762 struct sock *child)
763{
764 sk->sk_prot->disconnect(child, O_NONBLOCK);
765
766 sock_orphan(child);
767
768 percpu_counter_inc(sk->sk_prot->orphan_count);
769
770 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
771 BUG_ON(tcp_sk(child)->fastopen_rsk != req);
772 BUG_ON(sk != req->rsk_listener);
773
774 /* Paranoid, to prevent race condition if
775 * an inbound pkt destined for child is
776 * blocked by sock lock in tcp_v4_rcv().
777 * Also to satisfy an assertion in
778 * tcp_v4_destroy_sock().
779 */
780 tcp_sk(child)->fastopen_rsk = NULL;
781 }
782 inet_csk_destroy_sock(child);
783 reqsk_put(req);
784}
785
786struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
787 struct request_sock *req,
788 struct sock *child)
789{
790 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
791
792 spin_lock(&queue->rskq_lock);
793 if (unlikely(sk->sk_state != TCP_LISTEN)) {
794 inet_child_forget(sk, req, child);
795 child = NULL;
796 } else {
797 req->sk = child;
798 req->dl_next = NULL;
799 if (queue->rskq_accept_head == NULL)
800 queue->rskq_accept_head = req;
801 else
802 queue->rskq_accept_tail->dl_next = req;
803 queue->rskq_accept_tail = req;
804 sk_acceptq_added(sk);
805 }
806 spin_unlock(&queue->rskq_lock);
807 return child;
808}
809EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
810
811struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
812 struct request_sock *req, bool own_req)
813{
814 if (own_req) {
815 inet_csk_reqsk_queue_drop(sk, req);
816 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
817 if (inet_csk_reqsk_queue_add(sk, req, child))
818 return child;
819 }
820 /* Too bad, another child took ownership of the request, undo. */
821 bh_unlock_sock(child);
822 sock_put(child);
823 return NULL;
824}
825EXPORT_SYMBOL(inet_csk_complete_hashdance);
826
827/*
828 * This routine closes sockets which have been at least partially
829 * opened, but not yet accepted.
830 */
831void inet_csk_listen_stop(struct sock *sk)
832{
833 struct inet_connection_sock *icsk = inet_csk(sk);
834 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
835 struct request_sock *next, *req;
836
837 /* Following specs, it would be better either to send FIN
838 * (and enter FIN-WAIT-1, it is normal close)
839 * or to send active reset (abort).
840 * Certainly, it is pretty dangerous while synflood, but it is
841 * bad justification for our negligence 8)
842 * To be honest, we are not able to make either
843 * of the variants now. --ANK
844 */
845 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
846 struct sock *child = req->sk;
847
848 local_bh_disable();
849 bh_lock_sock(child);
850 WARN_ON(sock_owned_by_user(child));
851 sock_hold(child);
852
853 inet_child_forget(sk, req, child);
854 bh_unlock_sock(child);
855 local_bh_enable();
856 sock_put(child);
857
858 cond_resched();
859 }
860 if (queue->fastopenq.rskq_rst_head) {
861 /* Free all the reqs queued in rskq_rst_head. */
862 spin_lock_bh(&queue->fastopenq.lock);
863 req = queue->fastopenq.rskq_rst_head;
864 queue->fastopenq.rskq_rst_head = NULL;
865 spin_unlock_bh(&queue->fastopenq.lock);
866 while (req != NULL) {
867 next = req->dl_next;
868 reqsk_put(req);
869 req = next;
870 }
871 }
872 WARN_ON_ONCE(sk->sk_ack_backlog);
873}
874EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
875
876void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
877{
878 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
879 const struct inet_sock *inet = inet_sk(sk);
880
881 sin->sin_family = AF_INET;
882 sin->sin_addr.s_addr = inet->inet_daddr;
883 sin->sin_port = inet->inet_dport;
884}
885EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
886
887#ifdef CONFIG_COMPAT
888int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
889 char __user *optval, int __user *optlen)
890{
891 const struct inet_connection_sock *icsk = inet_csk(sk);
892
893 if (icsk->icsk_af_ops->compat_getsockopt)
894 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
895 optval, optlen);
896 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
897 optval, optlen);
898}
899EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
900
901int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
902 char __user *optval, unsigned int optlen)
903{
904 const struct inet_connection_sock *icsk = inet_csk(sk);
905
906 if (icsk->icsk_af_ops->compat_setsockopt)
907 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
908 optval, optlen);
909 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
910 optval, optlen);
911}
912EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
913#endif
914
915static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
916{
917 const struct inet_sock *inet = inet_sk(sk);
918 const struct ip_options_rcu *inet_opt;
919 __be32 daddr = inet->inet_daddr;
920 struct flowi4 *fl4;
921 struct rtable *rt;
922
923 rcu_read_lock();
924 inet_opt = rcu_dereference(inet->inet_opt);
925 if (inet_opt && inet_opt->opt.srr)
926 daddr = inet_opt->opt.faddr;
927 fl4 = &fl->u.ip4;
928 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
929 inet->inet_saddr, inet->inet_dport,
930 inet->inet_sport, sk->sk_protocol,
931 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
932 if (IS_ERR(rt))
933 rt = NULL;
934 if (rt)
935 sk_setup_caps(sk, &rt->dst);
936 rcu_read_unlock();
937
938 return &rt->dst;
939}
940
941struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
942{
943 struct dst_entry *dst = __sk_dst_check(sk, 0);
944 struct inet_sock *inet = inet_sk(sk);
945
946 if (!dst) {
947 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
948 if (!dst)
949 goto out;
950 }
951 dst->ops->update_pmtu(dst, sk, NULL, mtu);
952
953 dst = __sk_dst_check(sk, 0);
954 if (!dst)
955 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
956out:
957 return dst;
958}
959EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);