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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_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses if IPv6
28 * only, and any IPv4 addresses if not IPv6 only
29 * match_wildcard == false: addresses must be exactly the same, i.e.
30 * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
31 * and 0.0.0.0 equals to 0.0.0.0 only
32 */
33static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6,
34 const struct in6_addr *sk2_rcv_saddr6,
35 __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
36 bool sk1_ipv6only, bool sk2_ipv6only,
37 bool match_wildcard)
38{
39 int addr_type = ipv6_addr_type(sk1_rcv_saddr6);
40 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
41
42 /* if both are mapped, treat as IPv4 */
43 if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
44 if (!sk2_ipv6only) {
45 if (sk1_rcv_saddr == sk2_rcv_saddr)
46 return true;
47 if (!sk1_rcv_saddr || !sk2_rcv_saddr)
48 return match_wildcard;
49 }
50 return false;
51 }
52
53 if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
54 return true;
55
56 if (addr_type2 == IPV6_ADDR_ANY && match_wildcard &&
57 !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
58 return true;
59
60 if (addr_type == IPV6_ADDR_ANY && match_wildcard &&
61 !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
62 return true;
63
64 if (sk2_rcv_saddr6 &&
65 ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6))
66 return true;
67
68 return false;
69}
70#endif
71
72/* match_wildcard == true: 0.0.0.0 equals to any IPv4 addresses
73 * match_wildcard == false: addresses must be exactly the same, i.e.
74 * 0.0.0.0 only equals to 0.0.0.0
75 */
76static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
77 bool sk2_ipv6only, bool match_wildcard)
78{
79 if (!sk2_ipv6only) {
80 if (sk1_rcv_saddr == sk2_rcv_saddr)
81 return true;
82 if (!sk1_rcv_saddr || !sk2_rcv_saddr)
83 return match_wildcard;
84 }
85 return false;
86}
87
88bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
89 bool match_wildcard)
90{
91#if IS_ENABLED(CONFIG_IPV6)
92 if (sk->sk_family == AF_INET6)
93 return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr,
94 inet6_rcv_saddr(sk2),
95 sk->sk_rcv_saddr,
96 sk2->sk_rcv_saddr,
97 ipv6_only_sock(sk),
98 ipv6_only_sock(sk2),
99 match_wildcard);
100#endif
101 return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr,
102 ipv6_only_sock(sk2), match_wildcard);
103}
104EXPORT_SYMBOL(inet_rcv_saddr_equal);
105
106bool inet_rcv_saddr_any(const struct sock *sk)
107{
108#if IS_ENABLED(CONFIG_IPV6)
109 if (sk->sk_family == AF_INET6)
110 return ipv6_addr_any(&sk->sk_v6_rcv_saddr);
111#endif
112 return !sk->sk_rcv_saddr;
113}
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 int l3mdev;
183
184 l3mdev = inet_sk_bound_l3mdev(sk);
185 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
186other_half_scan:
187 inet_get_local_port_range(net, &low, &high);
188 high++; /* [32768, 60999] -> [32768, 61000[ */
189 if (high - low < 4)
190 attempt_half = 0;
191 if (attempt_half) {
192 int half = low + (((high - low) >> 2) << 1);
193
194 if (attempt_half == 1)
195 high = half;
196 else
197 low = half;
198 }
199 remaining = high - low;
200 if (likely(remaining > 1))
201 remaining &= ~1U;
202
203 offset = prandom_u32() % remaining;
204 /* __inet_hash_connect() favors ports having @low parity
205 * We do the opposite to not pollute connect() users.
206 */
207 offset |= 1U;
208
209other_parity_scan:
210 port = low + offset;
211 for (i = 0; i < remaining; i += 2, port += 2) {
212 if (unlikely(port >= high))
213 port -= remaining;
214 if (inet_is_local_reserved_port(net, port))
215 continue;
216 head = &hinfo->bhash[inet_bhashfn(net, port,
217 hinfo->bhash_size)];
218 spin_lock_bh(&head->lock);
219 inet_bind_bucket_for_each(tb, &head->chain)
220 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
221 tb->port == port) {
222 if (!inet_csk_bind_conflict(sk, tb, false, false))
223 goto success;
224 goto next_port;
225 }
226 tb = NULL;
227 goto success;
228next_port:
229 spin_unlock_bh(&head->lock);
230 cond_resched();
231 }
232
233 offset--;
234 if (!(offset & 1))
235 goto other_parity_scan;
236
237 if (attempt_half == 1) {
238 /* OK we now try the upper half of the range */
239 attempt_half = 2;
240 goto other_half_scan;
241 }
242 return NULL;
243success:
244 *port_ret = port;
245 *tb_ret = tb;
246 return head;
247}
248
249static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
250 struct sock *sk)
251{
252 kuid_t uid = sock_i_uid(sk);
253
254 if (tb->fastreuseport <= 0)
255 return 0;
256 if (!sk->sk_reuseport)
257 return 0;
258 if (rcu_access_pointer(sk->sk_reuseport_cb))
259 return 0;
260 if (!uid_eq(tb->fastuid, uid))
261 return 0;
262 /* We only need to check the rcv_saddr if this tb was once marked
263 * without fastreuseport and then was reset, as we can only know that
264 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
265 * owners list.
266 */
267 if (tb->fastreuseport == FASTREUSEPORT_ANY)
268 return 1;
269#if IS_ENABLED(CONFIG_IPV6)
270 if (tb->fast_sk_family == AF_INET6)
271 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
272 inet6_rcv_saddr(sk),
273 tb->fast_rcv_saddr,
274 sk->sk_rcv_saddr,
275 tb->fast_ipv6_only,
276 ipv6_only_sock(sk), true);
277#endif
278 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
279 ipv6_only_sock(sk), true);
280}
281
282/* Obtain a reference to a local port for the given sock,
283 * if snum is zero it means select any available local port.
284 * We try to allocate an odd port (and leave even ports for connect())
285 */
286int inet_csk_get_port(struct sock *sk, unsigned short snum)
287{
288 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
289 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
290 int ret = 1, port = snum;
291 struct inet_bind_hashbucket *head;
292 struct net *net = sock_net(sk);
293 struct inet_bind_bucket *tb = NULL;
294 kuid_t uid = sock_i_uid(sk);
295 int l3mdev;
296
297 l3mdev = inet_sk_bound_l3mdev(sk);
298
299 if (!port) {
300 head = inet_csk_find_open_port(sk, &tb, &port);
301 if (!head)
302 return ret;
303 if (!tb)
304 goto tb_not_found;
305 goto success;
306 }
307 head = &hinfo->bhash[inet_bhashfn(net, port,
308 hinfo->bhash_size)];
309 spin_lock_bh(&head->lock);
310 inet_bind_bucket_for_each(tb, &head->chain)
311 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
312 tb->port == port)
313 goto tb_found;
314tb_not_found:
315 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
316 net, head, port, l3mdev);
317 if (!tb)
318 goto fail_unlock;
319tb_found:
320 if (!hlist_empty(&tb->owners)) {
321 if (sk->sk_reuse == SK_FORCE_REUSE)
322 goto success;
323
324 if ((tb->fastreuse > 0 && reuse) ||
325 sk_reuseport_match(tb, sk))
326 goto success;
327 if (inet_csk_bind_conflict(sk, tb, true, true))
328 goto fail_unlock;
329 }
330success:
331 if (hlist_empty(&tb->owners)) {
332 tb->fastreuse = reuse;
333 if (sk->sk_reuseport) {
334 tb->fastreuseport = FASTREUSEPORT_ANY;
335 tb->fastuid = uid;
336 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
337 tb->fast_ipv6_only = ipv6_only_sock(sk);
338 tb->fast_sk_family = sk->sk_family;
339#if IS_ENABLED(CONFIG_IPV6)
340 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
341#endif
342 } else {
343 tb->fastreuseport = 0;
344 }
345 } else {
346 if (!reuse)
347 tb->fastreuse = 0;
348 if (sk->sk_reuseport) {
349 /* We didn't match or we don't have fastreuseport set on
350 * the tb, but we have sk_reuseport set on this socket
351 * and we know that there are no bind conflicts with
352 * this socket in this tb, so reset our tb's reuseport
353 * settings so that any subsequent sockets that match
354 * our current socket will be put on the fast path.
355 *
356 * If we reset we need to set FASTREUSEPORT_STRICT so we
357 * do extra checking for all subsequent sk_reuseport
358 * socks.
359 */
360 if (!sk_reuseport_match(tb, sk)) {
361 tb->fastreuseport = FASTREUSEPORT_STRICT;
362 tb->fastuid = uid;
363 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
364 tb->fast_ipv6_only = ipv6_only_sock(sk);
365 tb->fast_sk_family = sk->sk_family;
366#if IS_ENABLED(CONFIG_IPV6)
367 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
368#endif
369 }
370 } else {
371 tb->fastreuseport = 0;
372 }
373 }
374 if (!inet_csk(sk)->icsk_bind_hash)
375 inet_bind_hash(sk, tb, port);
376 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
377 ret = 0;
378
379fail_unlock:
380 spin_unlock_bh(&head->lock);
381 return ret;
382}
383EXPORT_SYMBOL_GPL(inet_csk_get_port);
384
385/*
386 * Wait for an incoming connection, avoid race conditions. This must be called
387 * with the socket locked.
388 */
389static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
390{
391 struct inet_connection_sock *icsk = inet_csk(sk);
392 DEFINE_WAIT(wait);
393 int err;
394
395 /*
396 * True wake-one mechanism for incoming connections: only
397 * one process gets woken up, not the 'whole herd'.
398 * Since we do not 'race & poll' for established sockets
399 * anymore, the common case will execute the loop only once.
400 *
401 * Subtle issue: "add_wait_queue_exclusive()" will be added
402 * after any current non-exclusive waiters, and we know that
403 * it will always _stay_ after any new non-exclusive waiters
404 * because all non-exclusive waiters are added at the
405 * beginning of the wait-queue. As such, it's ok to "drop"
406 * our exclusiveness temporarily when we get woken up without
407 * having to remove and re-insert us on the wait queue.
408 */
409 for (;;) {
410 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
411 TASK_INTERRUPTIBLE);
412 release_sock(sk);
413 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
414 timeo = schedule_timeout(timeo);
415 sched_annotate_sleep();
416 lock_sock(sk);
417 err = 0;
418 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
419 break;
420 err = -EINVAL;
421 if (sk->sk_state != TCP_LISTEN)
422 break;
423 err = sock_intr_errno(timeo);
424 if (signal_pending(current))
425 break;
426 err = -EAGAIN;
427 if (!timeo)
428 break;
429 }
430 finish_wait(sk_sleep(sk), &wait);
431 return err;
432}
433
434/*
435 * This will accept the next outstanding connection.
436 */
437struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
438{
439 struct inet_connection_sock *icsk = inet_csk(sk);
440 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
441 struct request_sock *req;
442 struct sock *newsk;
443 int error;
444
445 lock_sock(sk);
446
447 /* We need to make sure that this socket is listening,
448 * and that it has something pending.
449 */
450 error = -EINVAL;
451 if (sk->sk_state != TCP_LISTEN)
452 goto out_err;
453
454 /* Find already established connection */
455 if (reqsk_queue_empty(queue)) {
456 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
457
458 /* If this is a non blocking socket don't sleep */
459 error = -EAGAIN;
460 if (!timeo)
461 goto out_err;
462
463 error = inet_csk_wait_for_connect(sk, timeo);
464 if (error)
465 goto out_err;
466 }
467 req = reqsk_queue_remove(queue, sk);
468 newsk = req->sk;
469
470 if (sk->sk_protocol == IPPROTO_TCP &&
471 tcp_rsk(req)->tfo_listener) {
472 spin_lock_bh(&queue->fastopenq.lock);
473 if (tcp_rsk(req)->tfo_listener) {
474 /* We are still waiting for the final ACK from 3WHS
475 * so can't free req now. Instead, we set req->sk to
476 * NULL to signify that the child socket is taken
477 * so reqsk_fastopen_remove() will free the req
478 * when 3WHS finishes (or is aborted).
479 */
480 req->sk = NULL;
481 req = NULL;
482 }
483 spin_unlock_bh(&queue->fastopenq.lock);
484 }
485out:
486 release_sock(sk);
487 if (req)
488 reqsk_put(req);
489 return newsk;
490out_err:
491 newsk = NULL;
492 req = NULL;
493 *err = error;
494 goto out;
495}
496EXPORT_SYMBOL(inet_csk_accept);
497
498/*
499 * Using different timers for retransmit, delayed acks and probes
500 * We may wish use just one timer maintaining a list of expire jiffies
501 * to optimize.
502 */
503void inet_csk_init_xmit_timers(struct sock *sk,
504 void (*retransmit_handler)(struct timer_list *t),
505 void (*delack_handler)(struct timer_list *t),
506 void (*keepalive_handler)(struct timer_list *t))
507{
508 struct inet_connection_sock *icsk = inet_csk(sk);
509
510 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
511 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
512 timer_setup(&sk->sk_timer, keepalive_handler, 0);
513 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
514}
515EXPORT_SYMBOL(inet_csk_init_xmit_timers);
516
517void inet_csk_clear_xmit_timers(struct sock *sk)
518{
519 struct inet_connection_sock *icsk = inet_csk(sk);
520
521 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
522
523 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
524 sk_stop_timer(sk, &icsk->icsk_delack_timer);
525 sk_stop_timer(sk, &sk->sk_timer);
526}
527EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
528
529void inet_csk_delete_keepalive_timer(struct sock *sk)
530{
531 sk_stop_timer(sk, &sk->sk_timer);
532}
533EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
534
535void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
536{
537 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
538}
539EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
540
541struct dst_entry *inet_csk_route_req(const struct sock *sk,
542 struct flowi4 *fl4,
543 const struct request_sock *req)
544{
545 const struct inet_request_sock *ireq = inet_rsk(req);
546 struct net *net = read_pnet(&ireq->ireq_net);
547 struct ip_options_rcu *opt;
548 struct rtable *rt;
549
550 rcu_read_lock();
551 opt = rcu_dereference(ireq->ireq_opt);
552
553 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
554 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
555 sk->sk_protocol, inet_sk_flowi_flags(sk),
556 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
557 ireq->ir_loc_addr, ireq->ir_rmt_port,
558 htons(ireq->ir_num), sk->sk_uid);
559 security_req_classify_flow(req, flowi4_to_flowi(fl4));
560 rt = ip_route_output_flow(net, fl4, sk);
561 if (IS_ERR(rt))
562 goto no_route;
563 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
564 goto route_err;
565 rcu_read_unlock();
566 return &rt->dst;
567
568route_err:
569 ip_rt_put(rt);
570no_route:
571 rcu_read_unlock();
572 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
573 return NULL;
574}
575EXPORT_SYMBOL_GPL(inet_csk_route_req);
576
577struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
578 struct sock *newsk,
579 const struct request_sock *req)
580{
581 const struct inet_request_sock *ireq = inet_rsk(req);
582 struct net *net = read_pnet(&ireq->ireq_net);
583 struct inet_sock *newinet = inet_sk(newsk);
584 struct ip_options_rcu *opt;
585 struct flowi4 *fl4;
586 struct rtable *rt;
587
588 opt = rcu_dereference(ireq->ireq_opt);
589 fl4 = &newinet->cork.fl.u.ip4;
590
591 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
592 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
593 sk->sk_protocol, inet_sk_flowi_flags(sk),
594 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
595 ireq->ir_loc_addr, ireq->ir_rmt_port,
596 htons(ireq->ir_num), sk->sk_uid);
597 security_req_classify_flow(req, flowi4_to_flowi(fl4));
598 rt = ip_route_output_flow(net, fl4, sk);
599 if (IS_ERR(rt))
600 goto no_route;
601 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
602 goto route_err;
603 return &rt->dst;
604
605route_err:
606 ip_rt_put(rt);
607no_route:
608 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
609 return NULL;
610}
611EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
612
613#if IS_ENABLED(CONFIG_IPV6)
614#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
615#else
616#define AF_INET_FAMILY(fam) true
617#endif
618
619/* Decide when to expire the request and when to resend SYN-ACK */
620static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
621 const int max_retries,
622 const u8 rskq_defer_accept,
623 int *expire, int *resend)
624{
625 if (!rskq_defer_accept) {
626 *expire = req->num_timeout >= thresh;
627 *resend = 1;
628 return;
629 }
630 *expire = req->num_timeout >= thresh &&
631 (!inet_rsk(req)->acked || req->num_timeout >= max_retries);
632 /*
633 * Do not resend while waiting for data after ACK,
634 * start to resend on end of deferring period to give
635 * last chance for data or ACK to create established socket.
636 */
637 *resend = !inet_rsk(req)->acked ||
638 req->num_timeout >= rskq_defer_accept - 1;
639}
640
641int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
642{
643 int err = req->rsk_ops->rtx_syn_ack(parent, req);
644
645 if (!err)
646 req->num_retrans++;
647 return err;
648}
649EXPORT_SYMBOL(inet_rtx_syn_ack);
650
651/* return true if req was found in the ehash table */
652static bool reqsk_queue_unlink(struct request_sock *req)
653{
654 struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo;
655 bool found = false;
656
657 if (sk_hashed(req_to_sk(req))) {
658 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
659
660 spin_lock(lock);
661 found = __sk_nulls_del_node_init_rcu(req_to_sk(req));
662 spin_unlock(lock);
663 }
664 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
665 reqsk_put(req);
666 return found;
667}
668
669void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
670{
671 if (reqsk_queue_unlink(req)) {
672 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
673 reqsk_put(req);
674 }
675}
676EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
677
678void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
679{
680 inet_csk_reqsk_queue_drop(sk, req);
681 reqsk_put(req);
682}
683EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
684
685static void reqsk_timer_handler(struct timer_list *t)
686{
687 struct request_sock *req = from_timer(req, t, rsk_timer);
688 struct sock *sk_listener = req->rsk_listener;
689 struct net *net = sock_net(sk_listener);
690 struct inet_connection_sock *icsk = inet_csk(sk_listener);
691 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
692 int qlen, expire = 0, resend = 0;
693 int max_retries, thresh;
694 u8 defer_accept;
695
696 if (inet_sk_state_load(sk_listener) != TCP_LISTEN)
697 goto drop;
698
699 max_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries;
700 thresh = max_retries;
701 /* Normally all the openreqs are young and become mature
702 * (i.e. converted to established socket) for first timeout.
703 * If synack was not acknowledged for 1 second, it means
704 * one of the following things: synack was lost, ack was lost,
705 * rtt is high or nobody planned to ack (i.e. synflood).
706 * When server is a bit loaded, queue is populated with old
707 * open requests, reducing effective size of queue.
708 * When server is well loaded, queue size reduces to zero
709 * after several minutes of work. It is not synflood,
710 * it is normal operation. The solution is pruning
711 * too old entries overriding normal timeout, when
712 * situation becomes dangerous.
713 *
714 * Essentially, we reserve half of room for young
715 * embrions; and abort old ones without pity, if old
716 * ones are about to clog our table.
717 */
718 qlen = reqsk_queue_len(queue);
719 if ((qlen << 1) > max(8U, sk_listener->sk_max_ack_backlog)) {
720 int young = reqsk_queue_len_young(queue) << 1;
721
722 while (thresh > 2) {
723 if (qlen < young)
724 break;
725 thresh--;
726 young <<= 1;
727 }
728 }
729 defer_accept = READ_ONCE(queue->rskq_defer_accept);
730 if (defer_accept)
731 max_retries = defer_accept;
732 syn_ack_recalc(req, thresh, max_retries, defer_accept,
733 &expire, &resend);
734 req->rsk_ops->syn_ack_timeout(req);
735 if (!expire &&
736 (!resend ||
737 !inet_rtx_syn_ack(sk_listener, req) ||
738 inet_rsk(req)->acked)) {
739 unsigned long timeo;
740
741 if (req->num_timeout++ == 0)
742 atomic_dec(&queue->young);
743 timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
744 mod_timer(&req->rsk_timer, jiffies + timeo);
745 return;
746 }
747drop:
748 inet_csk_reqsk_queue_drop_and_put(sk_listener, req);
749}
750
751static void reqsk_queue_hash_req(struct request_sock *req,
752 unsigned long timeout)
753{
754 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
755 mod_timer(&req->rsk_timer, jiffies + timeout);
756
757 inet_ehash_insert(req_to_sk(req), NULL);
758 /* before letting lookups find us, make sure all req fields
759 * are committed to memory and refcnt initialized.
760 */
761 smp_wmb();
762 refcount_set(&req->rsk_refcnt, 2 + 1);
763}
764
765void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
766 unsigned long timeout)
767{
768 reqsk_queue_hash_req(req, timeout);
769 inet_csk_reqsk_queue_added(sk);
770}
771EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
772
773/**
774 * inet_csk_clone_lock - clone an inet socket, and lock its clone
775 * @sk: the socket to clone
776 * @req: request_sock
777 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
778 *
779 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
780 */
781struct sock *inet_csk_clone_lock(const struct sock *sk,
782 const struct request_sock *req,
783 const gfp_t priority)
784{
785 struct sock *newsk = sk_clone_lock(sk, priority);
786
787 if (newsk) {
788 struct inet_connection_sock *newicsk = inet_csk(newsk);
789
790 inet_sk_set_state(newsk, TCP_SYN_RECV);
791 newicsk->icsk_bind_hash = NULL;
792
793 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
794 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
795 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
796
797 /* listeners have SOCK_RCU_FREE, not the children */
798 sock_reset_flag(newsk, SOCK_RCU_FREE);
799
800 inet_sk(newsk)->mc_list = NULL;
801
802 newsk->sk_mark = inet_rsk(req)->ir_mark;
803 atomic64_set(&newsk->sk_cookie,
804 atomic64_read(&inet_rsk(req)->ir_cookie));
805
806 newicsk->icsk_retransmits = 0;
807 newicsk->icsk_backoff = 0;
808 newicsk->icsk_probes_out = 0;
809
810 /* Deinitialize accept_queue to trap illegal accesses. */
811 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
812
813 security_inet_csk_clone(newsk, req);
814 }
815 return newsk;
816}
817EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
818
819/*
820 * At this point, there should be no process reference to this
821 * socket, and thus no user references at all. Therefore we
822 * can assume the socket waitqueue is inactive and nobody will
823 * try to jump onto it.
824 */
825void inet_csk_destroy_sock(struct sock *sk)
826{
827 WARN_ON(sk->sk_state != TCP_CLOSE);
828 WARN_ON(!sock_flag(sk, SOCK_DEAD));
829
830 /* It cannot be in hash table! */
831 WARN_ON(!sk_unhashed(sk));
832
833 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
834 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
835
836 sk->sk_prot->destroy(sk);
837
838 sk_stream_kill_queues(sk);
839
840 xfrm_sk_free_policy(sk);
841
842 sk_refcnt_debug_release(sk);
843
844 percpu_counter_dec(sk->sk_prot->orphan_count);
845
846 sock_put(sk);
847}
848EXPORT_SYMBOL(inet_csk_destroy_sock);
849
850/* This function allows to force a closure of a socket after the call to
851 * tcp/dccp_create_openreq_child().
852 */
853void inet_csk_prepare_forced_close(struct sock *sk)
854 __releases(&sk->sk_lock.slock)
855{
856 /* sk_clone_lock locked the socket and set refcnt to 2 */
857 bh_unlock_sock(sk);
858 sock_put(sk);
859
860 /* The below has to be done to allow calling inet_csk_destroy_sock */
861 sock_set_flag(sk, SOCK_DEAD);
862 percpu_counter_inc(sk->sk_prot->orphan_count);
863 inet_sk(sk)->inet_num = 0;
864}
865EXPORT_SYMBOL(inet_csk_prepare_forced_close);
866
867int inet_csk_listen_start(struct sock *sk, int backlog)
868{
869 struct inet_connection_sock *icsk = inet_csk(sk);
870 struct inet_sock *inet = inet_sk(sk);
871 int err = -EADDRINUSE;
872
873 reqsk_queue_alloc(&icsk->icsk_accept_queue);
874
875 sk->sk_ack_backlog = 0;
876 inet_csk_delack_init(sk);
877
878 /* There is race window here: we announce ourselves listening,
879 * but this transition is still not validated by get_port().
880 * It is OK, because this socket enters to hash table only
881 * after validation is complete.
882 */
883 inet_sk_state_store(sk, TCP_LISTEN);
884 if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
885 inet->inet_sport = htons(inet->inet_num);
886
887 sk_dst_reset(sk);
888 err = sk->sk_prot->hash(sk);
889
890 if (likely(!err))
891 return 0;
892 }
893
894 inet_sk_set_state(sk, TCP_CLOSE);
895 return err;
896}
897EXPORT_SYMBOL_GPL(inet_csk_listen_start);
898
899static void inet_child_forget(struct sock *sk, struct request_sock *req,
900 struct sock *child)
901{
902 sk->sk_prot->disconnect(child, O_NONBLOCK);
903
904 sock_orphan(child);
905
906 percpu_counter_inc(sk->sk_prot->orphan_count);
907
908 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
909 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req);
910 BUG_ON(sk != req->rsk_listener);
911
912 /* Paranoid, to prevent race condition if
913 * an inbound pkt destined for child is
914 * blocked by sock lock in tcp_v4_rcv().
915 * Also to satisfy an assertion in
916 * tcp_v4_destroy_sock().
917 */
918 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL);
919 }
920 inet_csk_destroy_sock(child);
921}
922
923struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
924 struct request_sock *req,
925 struct sock *child)
926{
927 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
928
929 spin_lock(&queue->rskq_lock);
930 if (unlikely(sk->sk_state != TCP_LISTEN)) {
931 inet_child_forget(sk, req, child);
932 child = NULL;
933 } else {
934 req->sk = child;
935 req->dl_next = NULL;
936 if (queue->rskq_accept_head == NULL)
937 WRITE_ONCE(queue->rskq_accept_head, req);
938 else
939 queue->rskq_accept_tail->dl_next = req;
940 queue->rskq_accept_tail = req;
941 sk_acceptq_added(sk);
942 }
943 spin_unlock(&queue->rskq_lock);
944 return child;
945}
946EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
947
948struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
949 struct request_sock *req, bool own_req)
950{
951 if (own_req) {
952 inet_csk_reqsk_queue_drop(sk, req);
953 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
954 if (inet_csk_reqsk_queue_add(sk, req, child))
955 return child;
956 }
957 /* Too bad, another child took ownership of the request, undo. */
958 bh_unlock_sock(child);
959 sock_put(child);
960 return NULL;
961}
962EXPORT_SYMBOL(inet_csk_complete_hashdance);
963
964/*
965 * This routine closes sockets which have been at least partially
966 * opened, but not yet accepted.
967 */
968void inet_csk_listen_stop(struct sock *sk)
969{
970 struct inet_connection_sock *icsk = inet_csk(sk);
971 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
972 struct request_sock *next, *req;
973
974 /* Following specs, it would be better either to send FIN
975 * (and enter FIN-WAIT-1, it is normal close)
976 * or to send active reset (abort).
977 * Certainly, it is pretty dangerous while synflood, but it is
978 * bad justification for our negligence 8)
979 * To be honest, we are not able to make either
980 * of the variants now. --ANK
981 */
982 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
983 struct sock *child = req->sk;
984
985 local_bh_disable();
986 bh_lock_sock(child);
987 WARN_ON(sock_owned_by_user(child));
988 sock_hold(child);
989
990 inet_child_forget(sk, req, child);
991 reqsk_put(req);
992 bh_unlock_sock(child);
993 local_bh_enable();
994 sock_put(child);
995
996 cond_resched();
997 }
998 if (queue->fastopenq.rskq_rst_head) {
999 /* Free all the reqs queued in rskq_rst_head. */
1000 spin_lock_bh(&queue->fastopenq.lock);
1001 req = queue->fastopenq.rskq_rst_head;
1002 queue->fastopenq.rskq_rst_head = NULL;
1003 spin_unlock_bh(&queue->fastopenq.lock);
1004 while (req != NULL) {
1005 next = req->dl_next;
1006 reqsk_put(req);
1007 req = next;
1008 }
1009 }
1010 WARN_ON_ONCE(sk->sk_ack_backlog);
1011}
1012EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1013
1014void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1015{
1016 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1017 const struct inet_sock *inet = inet_sk(sk);
1018
1019 sin->sin_family = AF_INET;
1020 sin->sin_addr.s_addr = inet->inet_daddr;
1021 sin->sin_port = inet->inet_dport;
1022}
1023EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1024
1025#ifdef CONFIG_COMPAT
1026int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
1027 char __user *optval, int __user *optlen)
1028{
1029 const struct inet_connection_sock *icsk = inet_csk(sk);
1030
1031 if (icsk->icsk_af_ops->compat_getsockopt)
1032 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
1033 optval, optlen);
1034 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
1035 optval, optlen);
1036}
1037EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
1038
1039int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
1040 char __user *optval, unsigned int optlen)
1041{
1042 const struct inet_connection_sock *icsk = inet_csk(sk);
1043
1044 if (icsk->icsk_af_ops->compat_setsockopt)
1045 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
1046 optval, optlen);
1047 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1048 optval, optlen);
1049}
1050EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
1051#endif
1052
1053static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1054{
1055 const struct inet_sock *inet = inet_sk(sk);
1056 const struct ip_options_rcu *inet_opt;
1057 __be32 daddr = inet->inet_daddr;
1058 struct flowi4 *fl4;
1059 struct rtable *rt;
1060
1061 rcu_read_lock();
1062 inet_opt = rcu_dereference(inet->inet_opt);
1063 if (inet_opt && inet_opt->opt.srr)
1064 daddr = inet_opt->opt.faddr;
1065 fl4 = &fl->u.ip4;
1066 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
1067 inet->inet_saddr, inet->inet_dport,
1068 inet->inet_sport, sk->sk_protocol,
1069 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
1070 if (IS_ERR(rt))
1071 rt = NULL;
1072 if (rt)
1073 sk_setup_caps(sk, &rt->dst);
1074 rcu_read_unlock();
1075
1076 return &rt->dst;
1077}
1078
1079struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1080{
1081 struct dst_entry *dst = __sk_dst_check(sk, 0);
1082 struct inet_sock *inet = inet_sk(sk);
1083
1084 if (!dst) {
1085 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1086 if (!dst)
1087 goto out;
1088 }
1089 dst->ops->update_pmtu(dst, sk, NULL, mtu);
1090
1091 dst = __sk_dst_check(sk, 0);
1092 if (!dst)
1093 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1094out:
1095 return dst;
1096}
1097EXPORT_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
27#ifdef INET_CSK_DEBUG
28const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
29EXPORT_SYMBOL(inet_csk_timer_bug_msg);
30#endif
31
32/*
33 * This struct holds the first and last local port number.
34 */
35struct local_ports sysctl_local_ports __read_mostly = {
36 .lock = __SEQLOCK_UNLOCKED(sysctl_local_ports.lock),
37 .range = { 32768, 61000 },
38};
39
40unsigned long *sysctl_local_reserved_ports;
41EXPORT_SYMBOL(sysctl_local_reserved_ports);
42
43void inet_get_local_port_range(int *low, int *high)
44{
45 unsigned int seq;
46
47 do {
48 seq = read_seqbegin(&sysctl_local_ports.lock);
49
50 *low = sysctl_local_ports.range[0];
51 *high = sysctl_local_ports.range[1];
52 } while (read_seqretry(&sysctl_local_ports.lock, seq));
53}
54EXPORT_SYMBOL(inet_get_local_port_range);
55
56int inet_csk_bind_conflict(const struct sock *sk,
57 const struct inet_bind_bucket *tb, bool relax)
58{
59 struct sock *sk2;
60 struct hlist_node *node;
61 int reuse = sk->sk_reuse;
62
63 /*
64 * Unlike other sk lookup places we do not check
65 * for sk_net here, since _all_ the socks listed
66 * in tb->owners list belong to the same net - the
67 * one this bucket belongs to.
68 */
69
70 sk_for_each_bound(sk2, node, &tb->owners) {
71 if (sk != sk2 &&
72 !inet_v6_ipv6only(sk2) &&
73 (!sk->sk_bound_dev_if ||
74 !sk2->sk_bound_dev_if ||
75 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
76 if (!reuse || !sk2->sk_reuse ||
77 sk2->sk_state == TCP_LISTEN) {
78 const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
79 if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||
80 sk2_rcv_saddr == sk_rcv_saddr(sk))
81 break;
82 }
83 if (!relax && reuse && sk2->sk_reuse &&
84 sk2->sk_state != TCP_LISTEN) {
85 const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
86
87 if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||
88 sk2_rcv_saddr == sk_rcv_saddr(sk))
89 break;
90 }
91 }
92 }
93 return node != NULL;
94}
95EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
96
97/* Obtain a reference to a local port for the given sock,
98 * if snum is zero it means select any available local port.
99 */
100int inet_csk_get_port(struct sock *sk, unsigned short snum)
101{
102 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
103 struct inet_bind_hashbucket *head;
104 struct hlist_node *node;
105 struct inet_bind_bucket *tb;
106 int ret, attempts = 5;
107 struct net *net = sock_net(sk);
108 int smallest_size = -1, smallest_rover;
109
110 local_bh_disable();
111 if (!snum) {
112 int remaining, rover, low, high;
113
114again:
115 inet_get_local_port_range(&low, &high);
116 remaining = (high - low) + 1;
117 smallest_rover = rover = net_random() % remaining + low;
118
119 smallest_size = -1;
120 do {
121 if (inet_is_reserved_local_port(rover))
122 goto next_nolock;
123 head = &hashinfo->bhash[inet_bhashfn(net, rover,
124 hashinfo->bhash_size)];
125 spin_lock(&head->lock);
126 inet_bind_bucket_for_each(tb, node, &head->chain)
127 if (net_eq(ib_net(tb), net) && tb->port == rover) {
128 if (tb->fastreuse > 0 &&
129 sk->sk_reuse &&
130 sk->sk_state != TCP_LISTEN &&
131 (tb->num_owners < smallest_size || smallest_size == -1)) {
132 smallest_size = tb->num_owners;
133 smallest_rover = rover;
134 if (atomic_read(&hashinfo->bsockets) > (high - low) + 1 &&
135 !inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
136 snum = smallest_rover;
137 goto tb_found;
138 }
139 }
140 if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
141 snum = rover;
142 goto tb_found;
143 }
144 goto next;
145 }
146 break;
147 next:
148 spin_unlock(&head->lock);
149 next_nolock:
150 if (++rover > high)
151 rover = low;
152 } while (--remaining > 0);
153
154 /* Exhausted local port range during search? It is not
155 * possible for us to be holding one of the bind hash
156 * locks if this test triggers, because if 'remaining'
157 * drops to zero, we broke out of the do/while loop at
158 * the top level, not from the 'break;' statement.
159 */
160 ret = 1;
161 if (remaining <= 0) {
162 if (smallest_size != -1) {
163 snum = smallest_rover;
164 goto have_snum;
165 }
166 goto fail;
167 }
168 /* OK, here is the one we will use. HEAD is
169 * non-NULL and we hold it's mutex.
170 */
171 snum = rover;
172 } else {
173have_snum:
174 head = &hashinfo->bhash[inet_bhashfn(net, snum,
175 hashinfo->bhash_size)];
176 spin_lock(&head->lock);
177 inet_bind_bucket_for_each(tb, node, &head->chain)
178 if (net_eq(ib_net(tb), net) && tb->port == snum)
179 goto tb_found;
180 }
181 tb = NULL;
182 goto tb_not_found;
183tb_found:
184 if (!hlist_empty(&tb->owners)) {
185 if (sk->sk_reuse == SK_FORCE_REUSE)
186 goto success;
187
188 if (tb->fastreuse > 0 &&
189 sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
190 smallest_size == -1) {
191 goto success;
192 } else {
193 ret = 1;
194 if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) {
195 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
196 smallest_size != -1 && --attempts >= 0) {
197 spin_unlock(&head->lock);
198 goto again;
199 }
200
201 goto fail_unlock;
202 }
203 }
204 }
205tb_not_found:
206 ret = 1;
207 if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
208 net, head, snum)) == NULL)
209 goto fail_unlock;
210 if (hlist_empty(&tb->owners)) {
211 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
212 tb->fastreuse = 1;
213 else
214 tb->fastreuse = 0;
215 } else if (tb->fastreuse &&
216 (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
217 tb->fastreuse = 0;
218success:
219 if (!inet_csk(sk)->icsk_bind_hash)
220 inet_bind_hash(sk, tb, snum);
221 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
222 ret = 0;
223
224fail_unlock:
225 spin_unlock(&head->lock);
226fail:
227 local_bh_enable();
228 return ret;
229}
230EXPORT_SYMBOL_GPL(inet_csk_get_port);
231
232/*
233 * Wait for an incoming connection, avoid race conditions. This must be called
234 * with the socket locked.
235 */
236static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
237{
238 struct inet_connection_sock *icsk = inet_csk(sk);
239 DEFINE_WAIT(wait);
240 int err;
241
242 /*
243 * True wake-one mechanism for incoming connections: only
244 * one process gets woken up, not the 'whole herd'.
245 * Since we do not 'race & poll' for established sockets
246 * anymore, the common case will execute the loop only once.
247 *
248 * Subtle issue: "add_wait_queue_exclusive()" will be added
249 * after any current non-exclusive waiters, and we know that
250 * it will always _stay_ after any new non-exclusive waiters
251 * because all non-exclusive waiters are added at the
252 * beginning of the wait-queue. As such, it's ok to "drop"
253 * our exclusiveness temporarily when we get woken up without
254 * having to remove and re-insert us on the wait queue.
255 */
256 for (;;) {
257 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
258 TASK_INTERRUPTIBLE);
259 release_sock(sk);
260 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
261 timeo = schedule_timeout(timeo);
262 lock_sock(sk);
263 err = 0;
264 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
265 break;
266 err = -EINVAL;
267 if (sk->sk_state != TCP_LISTEN)
268 break;
269 err = sock_intr_errno(timeo);
270 if (signal_pending(current))
271 break;
272 err = -EAGAIN;
273 if (!timeo)
274 break;
275 }
276 finish_wait(sk_sleep(sk), &wait);
277 return err;
278}
279
280/*
281 * This will accept the next outstanding connection.
282 */
283struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
284{
285 struct inet_connection_sock *icsk = inet_csk(sk);
286 struct sock *newsk;
287 int error;
288
289 lock_sock(sk);
290
291 /* We need to make sure that this socket is listening,
292 * and that it has something pending.
293 */
294 error = -EINVAL;
295 if (sk->sk_state != TCP_LISTEN)
296 goto out_err;
297
298 /* Find already established connection */
299 if (reqsk_queue_empty(&icsk->icsk_accept_queue)) {
300 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
301
302 /* If this is a non blocking socket don't sleep */
303 error = -EAGAIN;
304 if (!timeo)
305 goto out_err;
306
307 error = inet_csk_wait_for_connect(sk, timeo);
308 if (error)
309 goto out_err;
310 }
311
312 newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
313 WARN_ON(newsk->sk_state == TCP_SYN_RECV);
314out:
315 release_sock(sk);
316 return newsk;
317out_err:
318 newsk = NULL;
319 *err = error;
320 goto out;
321}
322EXPORT_SYMBOL(inet_csk_accept);
323
324/*
325 * Using different timers for retransmit, delayed acks and probes
326 * We may wish use just one timer maintaining a list of expire jiffies
327 * to optimize.
328 */
329void inet_csk_init_xmit_timers(struct sock *sk,
330 void (*retransmit_handler)(unsigned long),
331 void (*delack_handler)(unsigned long),
332 void (*keepalive_handler)(unsigned long))
333{
334 struct inet_connection_sock *icsk = inet_csk(sk);
335
336 setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
337 (unsigned long)sk);
338 setup_timer(&icsk->icsk_delack_timer, delack_handler,
339 (unsigned long)sk);
340 setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
341 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
342}
343EXPORT_SYMBOL(inet_csk_init_xmit_timers);
344
345void inet_csk_clear_xmit_timers(struct sock *sk)
346{
347 struct inet_connection_sock *icsk = inet_csk(sk);
348
349 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
350
351 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
352 sk_stop_timer(sk, &icsk->icsk_delack_timer);
353 sk_stop_timer(sk, &sk->sk_timer);
354}
355EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
356
357void inet_csk_delete_keepalive_timer(struct sock *sk)
358{
359 sk_stop_timer(sk, &sk->sk_timer);
360}
361EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
362
363void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
364{
365 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
366}
367EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
368
369struct dst_entry *inet_csk_route_req(struct sock *sk,
370 struct flowi4 *fl4,
371 const struct request_sock *req)
372{
373 struct rtable *rt;
374 const struct inet_request_sock *ireq = inet_rsk(req);
375 struct ip_options_rcu *opt = inet_rsk(req)->opt;
376 struct net *net = sock_net(sk);
377
378 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
379 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
380 sk->sk_protocol,
381 inet_sk_flowi_flags(sk) & ~FLOWI_FLAG_PRECOW_METRICS,
382 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr,
383 ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport);
384 security_req_classify_flow(req, flowi4_to_flowi(fl4));
385 rt = ip_route_output_flow(net, fl4, sk);
386 if (IS_ERR(rt))
387 goto no_route;
388 if (opt && opt->opt.is_strictroute && fl4->daddr != rt->rt_gateway)
389 goto route_err;
390 return &rt->dst;
391
392route_err:
393 ip_rt_put(rt);
394no_route:
395 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
396 return NULL;
397}
398EXPORT_SYMBOL_GPL(inet_csk_route_req);
399
400struct dst_entry *inet_csk_route_child_sock(struct sock *sk,
401 struct sock *newsk,
402 const struct request_sock *req)
403{
404 const struct inet_request_sock *ireq = inet_rsk(req);
405 struct inet_sock *newinet = inet_sk(newsk);
406 struct ip_options_rcu *opt = ireq->opt;
407 struct net *net = sock_net(sk);
408 struct flowi4 *fl4;
409 struct rtable *rt;
410
411 fl4 = &newinet->cork.fl.u.ip4;
412 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
413 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
414 sk->sk_protocol, inet_sk_flowi_flags(sk),
415 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr,
416 ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport);
417 security_req_classify_flow(req, flowi4_to_flowi(fl4));
418 rt = ip_route_output_flow(net, fl4, sk);
419 if (IS_ERR(rt))
420 goto no_route;
421 if (opt && opt->opt.is_strictroute && fl4->daddr != rt->rt_gateway)
422 goto route_err;
423 return &rt->dst;
424
425route_err:
426 ip_rt_put(rt);
427no_route:
428 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
429 return NULL;
430}
431EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
432
433static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
434 const u32 rnd, const u32 synq_hsize)
435{
436 return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
437}
438
439#if IS_ENABLED(CONFIG_IPV6)
440#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
441#else
442#define AF_INET_FAMILY(fam) 1
443#endif
444
445struct request_sock *inet_csk_search_req(const struct sock *sk,
446 struct request_sock ***prevp,
447 const __be16 rport, const __be32 raddr,
448 const __be32 laddr)
449{
450 const struct inet_connection_sock *icsk = inet_csk(sk);
451 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
452 struct request_sock *req, **prev;
453
454 for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd,
455 lopt->nr_table_entries)];
456 (req = *prev) != NULL;
457 prev = &req->dl_next) {
458 const struct inet_request_sock *ireq = inet_rsk(req);
459
460 if (ireq->rmt_port == rport &&
461 ireq->rmt_addr == raddr &&
462 ireq->loc_addr == laddr &&
463 AF_INET_FAMILY(req->rsk_ops->family)) {
464 WARN_ON(req->sk);
465 *prevp = prev;
466 break;
467 }
468 }
469
470 return req;
471}
472EXPORT_SYMBOL_GPL(inet_csk_search_req);
473
474void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
475 unsigned long timeout)
476{
477 struct inet_connection_sock *icsk = inet_csk(sk);
478 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
479 const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port,
480 lopt->hash_rnd, lopt->nr_table_entries);
481
482 reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
483 inet_csk_reqsk_queue_added(sk, timeout);
484}
485EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
486
487/* Only thing we need from tcp.h */
488extern int sysctl_tcp_synack_retries;
489
490
491/* Decide when to expire the request and when to resend SYN-ACK */
492static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
493 const int max_retries,
494 const u8 rskq_defer_accept,
495 int *expire, int *resend)
496{
497 if (!rskq_defer_accept) {
498 *expire = req->retrans >= thresh;
499 *resend = 1;
500 return;
501 }
502 *expire = req->retrans >= thresh &&
503 (!inet_rsk(req)->acked || req->retrans >= max_retries);
504 /*
505 * Do not resend while waiting for data after ACK,
506 * start to resend on end of deferring period to give
507 * last chance for data or ACK to create established socket.
508 */
509 *resend = !inet_rsk(req)->acked ||
510 req->retrans >= rskq_defer_accept - 1;
511}
512
513void inet_csk_reqsk_queue_prune(struct sock *parent,
514 const unsigned long interval,
515 const unsigned long timeout,
516 const unsigned long max_rto)
517{
518 struct inet_connection_sock *icsk = inet_csk(parent);
519 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
520 struct listen_sock *lopt = queue->listen_opt;
521 int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
522 int thresh = max_retries;
523 unsigned long now = jiffies;
524 struct request_sock **reqp, *req;
525 int i, budget;
526
527 if (lopt == NULL || lopt->qlen == 0)
528 return;
529
530 /* Normally all the openreqs are young and become mature
531 * (i.e. converted to established socket) for first timeout.
532 * If synack was not acknowledged for 1 second, it means
533 * one of the following things: synack was lost, ack was lost,
534 * rtt is high or nobody planned to ack (i.e. synflood).
535 * When server is a bit loaded, queue is populated with old
536 * open requests, reducing effective size of queue.
537 * When server is well loaded, queue size reduces to zero
538 * after several minutes of work. It is not synflood,
539 * it is normal operation. The solution is pruning
540 * too old entries overriding normal timeout, when
541 * situation becomes dangerous.
542 *
543 * Essentially, we reserve half of room for young
544 * embrions; and abort old ones without pity, if old
545 * ones are about to clog our table.
546 */
547 if (lopt->qlen>>(lopt->max_qlen_log-1)) {
548 int young = (lopt->qlen_young<<1);
549
550 while (thresh > 2) {
551 if (lopt->qlen < young)
552 break;
553 thresh--;
554 young <<= 1;
555 }
556 }
557
558 if (queue->rskq_defer_accept)
559 max_retries = queue->rskq_defer_accept;
560
561 budget = 2 * (lopt->nr_table_entries / (timeout / interval));
562 i = lopt->clock_hand;
563
564 do {
565 reqp=&lopt->syn_table[i];
566 while ((req = *reqp) != NULL) {
567 if (time_after_eq(now, req->expires)) {
568 int expire = 0, resend = 0;
569
570 syn_ack_recalc(req, thresh, max_retries,
571 queue->rskq_defer_accept,
572 &expire, &resend);
573 req->rsk_ops->syn_ack_timeout(parent, req);
574 if (!expire &&
575 (!resend ||
576 !req->rsk_ops->rtx_syn_ack(parent, req, NULL) ||
577 inet_rsk(req)->acked)) {
578 unsigned long timeo;
579
580 if (req->retrans++ == 0)
581 lopt->qlen_young--;
582 timeo = min((timeout << req->retrans), max_rto);
583 req->expires = now + timeo;
584 reqp = &req->dl_next;
585 continue;
586 }
587
588 /* Drop this request */
589 inet_csk_reqsk_queue_unlink(parent, req, reqp);
590 reqsk_queue_removed(queue, req);
591 reqsk_free(req);
592 continue;
593 }
594 reqp = &req->dl_next;
595 }
596
597 i = (i + 1) & (lopt->nr_table_entries - 1);
598
599 } while (--budget > 0);
600
601 lopt->clock_hand = i;
602
603 if (lopt->qlen)
604 inet_csk_reset_keepalive_timer(parent, interval);
605}
606EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
607
608/**
609 * inet_csk_clone_lock - clone an inet socket, and lock its clone
610 * @sk: the socket to clone
611 * @req: request_sock
612 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
613 *
614 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
615 */
616struct sock *inet_csk_clone_lock(const struct sock *sk,
617 const struct request_sock *req,
618 const gfp_t priority)
619{
620 struct sock *newsk = sk_clone_lock(sk, priority);
621
622 if (newsk != NULL) {
623 struct inet_connection_sock *newicsk = inet_csk(newsk);
624
625 newsk->sk_state = TCP_SYN_RECV;
626 newicsk->icsk_bind_hash = NULL;
627
628 inet_sk(newsk)->inet_dport = inet_rsk(req)->rmt_port;
629 inet_sk(newsk)->inet_num = ntohs(inet_rsk(req)->loc_port);
630 inet_sk(newsk)->inet_sport = inet_rsk(req)->loc_port;
631 newsk->sk_write_space = sk_stream_write_space;
632
633 newicsk->icsk_retransmits = 0;
634 newicsk->icsk_backoff = 0;
635 newicsk->icsk_probes_out = 0;
636
637 /* Deinitialize accept_queue to trap illegal accesses. */
638 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
639
640 security_inet_csk_clone(newsk, req);
641 }
642 return newsk;
643}
644EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
645
646/*
647 * At this point, there should be no process reference to this
648 * socket, and thus no user references at all. Therefore we
649 * can assume the socket waitqueue is inactive and nobody will
650 * try to jump onto it.
651 */
652void inet_csk_destroy_sock(struct sock *sk)
653{
654 WARN_ON(sk->sk_state != TCP_CLOSE);
655 WARN_ON(!sock_flag(sk, SOCK_DEAD));
656
657 /* It cannot be in hash table! */
658 WARN_ON(!sk_unhashed(sk));
659
660 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
661 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
662
663 sk->sk_prot->destroy(sk);
664
665 sk_stream_kill_queues(sk);
666
667 xfrm_sk_free_policy(sk);
668
669 sk_refcnt_debug_release(sk);
670
671 percpu_counter_dec(sk->sk_prot->orphan_count);
672 sock_put(sk);
673}
674EXPORT_SYMBOL(inet_csk_destroy_sock);
675
676int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
677{
678 struct inet_sock *inet = inet_sk(sk);
679 struct inet_connection_sock *icsk = inet_csk(sk);
680 int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
681
682 if (rc != 0)
683 return rc;
684
685 sk->sk_max_ack_backlog = 0;
686 sk->sk_ack_backlog = 0;
687 inet_csk_delack_init(sk);
688
689 /* There is race window here: we announce ourselves listening,
690 * but this transition is still not validated by get_port().
691 * It is OK, because this socket enters to hash table only
692 * after validation is complete.
693 */
694 sk->sk_state = TCP_LISTEN;
695 if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
696 inet->inet_sport = htons(inet->inet_num);
697
698 sk_dst_reset(sk);
699 sk->sk_prot->hash(sk);
700
701 return 0;
702 }
703
704 sk->sk_state = TCP_CLOSE;
705 __reqsk_queue_destroy(&icsk->icsk_accept_queue);
706 return -EADDRINUSE;
707}
708EXPORT_SYMBOL_GPL(inet_csk_listen_start);
709
710/*
711 * This routine closes sockets which have been at least partially
712 * opened, but not yet accepted.
713 */
714void inet_csk_listen_stop(struct sock *sk)
715{
716 struct inet_connection_sock *icsk = inet_csk(sk);
717 struct request_sock *acc_req;
718 struct request_sock *req;
719
720 inet_csk_delete_keepalive_timer(sk);
721
722 /* make all the listen_opt local to us */
723 acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue);
724
725 /* Following specs, it would be better either to send FIN
726 * (and enter FIN-WAIT-1, it is normal close)
727 * or to send active reset (abort).
728 * Certainly, it is pretty dangerous while synflood, but it is
729 * bad justification for our negligence 8)
730 * To be honest, we are not able to make either
731 * of the variants now. --ANK
732 */
733 reqsk_queue_destroy(&icsk->icsk_accept_queue);
734
735 while ((req = acc_req) != NULL) {
736 struct sock *child = req->sk;
737
738 acc_req = req->dl_next;
739
740 local_bh_disable();
741 bh_lock_sock(child);
742 WARN_ON(sock_owned_by_user(child));
743 sock_hold(child);
744
745 sk->sk_prot->disconnect(child, O_NONBLOCK);
746
747 sock_orphan(child);
748
749 percpu_counter_inc(sk->sk_prot->orphan_count);
750
751 inet_csk_destroy_sock(child);
752
753 bh_unlock_sock(child);
754 local_bh_enable();
755 sock_put(child);
756
757 sk_acceptq_removed(sk);
758 __reqsk_free(req);
759 }
760 WARN_ON(sk->sk_ack_backlog);
761}
762EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
763
764void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
765{
766 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
767 const struct inet_sock *inet = inet_sk(sk);
768
769 sin->sin_family = AF_INET;
770 sin->sin_addr.s_addr = inet->inet_daddr;
771 sin->sin_port = inet->inet_dport;
772}
773EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
774
775#ifdef CONFIG_COMPAT
776int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
777 char __user *optval, int __user *optlen)
778{
779 const struct inet_connection_sock *icsk = inet_csk(sk);
780
781 if (icsk->icsk_af_ops->compat_getsockopt != NULL)
782 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
783 optval, optlen);
784 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
785 optval, optlen);
786}
787EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
788
789int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
790 char __user *optval, unsigned int optlen)
791{
792 const struct inet_connection_sock *icsk = inet_csk(sk);
793
794 if (icsk->icsk_af_ops->compat_setsockopt != NULL)
795 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
796 optval, optlen);
797 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
798 optval, optlen);
799}
800EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
801#endif