Linux 2.6.19-rc6
[cris-mirror.git] / net / ipv4 / inet_connection_sock.c
blob96bbe2a0aa1b05e41fcd144e3b11a61b17d854ba
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.
6 * Support for INET connection oriented protocols.
8 * Authors: See the TCP sources
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.
16 #include <linux/module.h>
17 #include <linux/jhash.h>
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>
27 #ifdef INET_CSK_DEBUG
28 const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
29 EXPORT_SYMBOL(inet_csk_timer_bug_msg);
30 #endif
33 * This array holds the first and last local port number.
34 * For high-usage systems, use sysctl to change this to
35 * 32768-61000
37 int sysctl_local_port_range[2] = { 1024, 4999 };
39 int inet_csk_bind_conflict(const struct sock *sk,
40 const struct inet_bind_bucket *tb)
42 const __be32 sk_rcv_saddr = inet_rcv_saddr(sk);
43 struct sock *sk2;
44 struct hlist_node *node;
45 int reuse = sk->sk_reuse;
47 sk_for_each_bound(sk2, node, &tb->owners) {
48 if (sk != sk2 &&
49 !inet_v6_ipv6only(sk2) &&
50 (!sk->sk_bound_dev_if ||
51 !sk2->sk_bound_dev_if ||
52 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
53 if (!reuse || !sk2->sk_reuse ||
54 sk2->sk_state == TCP_LISTEN) {
55 const __be32 sk2_rcv_saddr = inet_rcv_saddr(sk2);
56 if (!sk2_rcv_saddr || !sk_rcv_saddr ||
57 sk2_rcv_saddr == sk_rcv_saddr)
58 break;
62 return node != NULL;
65 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
67 /* Obtain a reference to a local port for the given sock,
68 * if snum is zero it means select any available local port.
70 int inet_csk_get_port(struct inet_hashinfo *hashinfo,
71 struct sock *sk, unsigned short snum,
72 int (*bind_conflict)(const struct sock *sk,
73 const struct inet_bind_bucket *tb))
75 struct inet_bind_hashbucket *head;
76 struct hlist_node *node;
77 struct inet_bind_bucket *tb;
78 int ret;
80 local_bh_disable();
81 if (!snum) {
82 int low = sysctl_local_port_range[0];
83 int high = sysctl_local_port_range[1];
84 int remaining = (high - low) + 1;
85 int rover = net_random() % (high - low) + low;
87 do {
88 head = &hashinfo->bhash[inet_bhashfn(rover, hashinfo->bhash_size)];
89 spin_lock(&head->lock);
90 inet_bind_bucket_for_each(tb, node, &head->chain)
91 if (tb->port == rover)
92 goto next;
93 break;
94 next:
95 spin_unlock(&head->lock);
96 if (++rover > high)
97 rover = low;
98 } while (--remaining > 0);
100 /* Exhausted local port range during search? It is not
101 * possible for us to be holding one of the bind hash
102 * locks if this test triggers, because if 'remaining'
103 * drops to zero, we broke out of the do/while loop at
104 * the top level, not from the 'break;' statement.
106 ret = 1;
107 if (remaining <= 0)
108 goto fail;
110 /* OK, here is the one we will use. HEAD is
111 * non-NULL and we hold it's mutex.
113 snum = rover;
114 } else {
115 head = &hashinfo->bhash[inet_bhashfn(snum, hashinfo->bhash_size)];
116 spin_lock(&head->lock);
117 inet_bind_bucket_for_each(tb, node, &head->chain)
118 if (tb->port == snum)
119 goto tb_found;
121 tb = NULL;
122 goto tb_not_found;
123 tb_found:
124 if (!hlist_empty(&tb->owners)) {
125 if (sk->sk_reuse > 1)
126 goto success;
127 if (tb->fastreuse > 0 &&
128 sk->sk_reuse && sk->sk_state != TCP_LISTEN) {
129 goto success;
130 } else {
131 ret = 1;
132 if (bind_conflict(sk, tb))
133 goto fail_unlock;
136 tb_not_found:
137 ret = 1;
138 if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep, head, snum)) == NULL)
139 goto fail_unlock;
140 if (hlist_empty(&tb->owners)) {
141 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
142 tb->fastreuse = 1;
143 else
144 tb->fastreuse = 0;
145 } else if (tb->fastreuse &&
146 (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
147 tb->fastreuse = 0;
148 success:
149 if (!inet_csk(sk)->icsk_bind_hash)
150 inet_bind_hash(sk, tb, snum);
151 BUG_TRAP(inet_csk(sk)->icsk_bind_hash == tb);
152 ret = 0;
154 fail_unlock:
155 spin_unlock(&head->lock);
156 fail:
157 local_bh_enable();
158 return ret;
161 EXPORT_SYMBOL_GPL(inet_csk_get_port);
164 * Wait for an incoming connection, avoid race conditions. This must be called
165 * with the socket locked.
167 static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
169 struct inet_connection_sock *icsk = inet_csk(sk);
170 DEFINE_WAIT(wait);
171 int err;
174 * True wake-one mechanism for incoming connections: only
175 * one process gets woken up, not the 'whole herd'.
176 * Since we do not 'race & poll' for established sockets
177 * anymore, the common case will execute the loop only once.
179 * Subtle issue: "add_wait_queue_exclusive()" will be added
180 * after any current non-exclusive waiters, and we know that
181 * it will always _stay_ after any new non-exclusive waiters
182 * because all non-exclusive waiters are added at the
183 * beginning of the wait-queue. As such, it's ok to "drop"
184 * our exclusiveness temporarily when we get woken up without
185 * having to remove and re-insert us on the wait queue.
187 for (;;) {
188 prepare_to_wait_exclusive(sk->sk_sleep, &wait,
189 TASK_INTERRUPTIBLE);
190 release_sock(sk);
191 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
192 timeo = schedule_timeout(timeo);
193 lock_sock(sk);
194 err = 0;
195 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
196 break;
197 err = -EINVAL;
198 if (sk->sk_state != TCP_LISTEN)
199 break;
200 err = sock_intr_errno(timeo);
201 if (signal_pending(current))
202 break;
203 err = -EAGAIN;
204 if (!timeo)
205 break;
207 finish_wait(sk->sk_sleep, &wait);
208 return err;
212 * This will accept the next outstanding connection.
214 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
216 struct inet_connection_sock *icsk = inet_csk(sk);
217 struct sock *newsk;
218 int error;
220 lock_sock(sk);
222 /* We need to make sure that this socket is listening,
223 * and that it has something pending.
225 error = -EINVAL;
226 if (sk->sk_state != TCP_LISTEN)
227 goto out_err;
229 /* Find already established connection */
230 if (reqsk_queue_empty(&icsk->icsk_accept_queue)) {
231 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
233 /* If this is a non blocking socket don't sleep */
234 error = -EAGAIN;
235 if (!timeo)
236 goto out_err;
238 error = inet_csk_wait_for_connect(sk, timeo);
239 if (error)
240 goto out_err;
243 newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
244 BUG_TRAP(newsk->sk_state != TCP_SYN_RECV);
245 out:
246 release_sock(sk);
247 return newsk;
248 out_err:
249 newsk = NULL;
250 *err = error;
251 goto out;
254 EXPORT_SYMBOL(inet_csk_accept);
257 * Using different timers for retransmit, delayed acks and probes
258 * We may wish use just one timer maintaining a list of expire jiffies
259 * to optimize.
261 void inet_csk_init_xmit_timers(struct sock *sk,
262 void (*retransmit_handler)(unsigned long),
263 void (*delack_handler)(unsigned long),
264 void (*keepalive_handler)(unsigned long))
266 struct inet_connection_sock *icsk = inet_csk(sk);
268 init_timer(&icsk->icsk_retransmit_timer);
269 init_timer(&icsk->icsk_delack_timer);
270 init_timer(&sk->sk_timer);
272 icsk->icsk_retransmit_timer.function = retransmit_handler;
273 icsk->icsk_delack_timer.function = delack_handler;
274 sk->sk_timer.function = keepalive_handler;
276 icsk->icsk_retransmit_timer.data =
277 icsk->icsk_delack_timer.data =
278 sk->sk_timer.data = (unsigned long)sk;
280 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
283 EXPORT_SYMBOL(inet_csk_init_xmit_timers);
285 void inet_csk_clear_xmit_timers(struct sock *sk)
287 struct inet_connection_sock *icsk = inet_csk(sk);
289 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
291 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
292 sk_stop_timer(sk, &icsk->icsk_delack_timer);
293 sk_stop_timer(sk, &sk->sk_timer);
296 EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
298 void inet_csk_delete_keepalive_timer(struct sock *sk)
300 sk_stop_timer(sk, &sk->sk_timer);
303 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
305 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
307 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
310 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
312 struct dst_entry* inet_csk_route_req(struct sock *sk,
313 const struct request_sock *req)
315 struct rtable *rt;
316 const struct inet_request_sock *ireq = inet_rsk(req);
317 struct ip_options *opt = inet_rsk(req)->opt;
318 struct flowi fl = { .oif = sk->sk_bound_dev_if,
319 .nl_u = { .ip4_u =
320 { .daddr = ((opt && opt->srr) ?
321 opt->faddr :
322 ireq->rmt_addr),
323 .saddr = ireq->loc_addr,
324 .tos = RT_CONN_FLAGS(sk) } },
325 .proto = sk->sk_protocol,
326 .uli_u = { .ports =
327 { .sport = inet_sk(sk)->sport,
328 .dport = ireq->rmt_port } } };
330 security_req_classify_flow(req, &fl);
331 if (ip_route_output_flow(&rt, &fl, sk, 0)) {
332 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
333 return NULL;
335 if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) {
336 ip_rt_put(rt);
337 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
338 return NULL;
340 return &rt->u.dst;
343 EXPORT_SYMBOL_GPL(inet_csk_route_req);
345 static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
346 const u32 rnd, const u16 synq_hsize)
348 return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
351 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
352 #define AF_INET_FAMILY(fam) ((fam) == AF_INET)
353 #else
354 #define AF_INET_FAMILY(fam) 1
355 #endif
357 struct request_sock *inet_csk_search_req(const struct sock *sk,
358 struct request_sock ***prevp,
359 const __be16 rport, const __be32 raddr,
360 const __be32 laddr)
362 const struct inet_connection_sock *icsk = inet_csk(sk);
363 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
364 struct request_sock *req, **prev;
366 for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd,
367 lopt->nr_table_entries)];
368 (req = *prev) != NULL;
369 prev = &req->dl_next) {
370 const struct inet_request_sock *ireq = inet_rsk(req);
372 if (ireq->rmt_port == rport &&
373 ireq->rmt_addr == raddr &&
374 ireq->loc_addr == laddr &&
375 AF_INET_FAMILY(req->rsk_ops->family)) {
376 BUG_TRAP(!req->sk);
377 *prevp = prev;
378 break;
382 return req;
385 EXPORT_SYMBOL_GPL(inet_csk_search_req);
387 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
388 unsigned long timeout)
390 struct inet_connection_sock *icsk = inet_csk(sk);
391 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
392 const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port,
393 lopt->hash_rnd, lopt->nr_table_entries);
395 reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
396 inet_csk_reqsk_queue_added(sk, timeout);
399 /* Only thing we need from tcp.h */
400 extern int sysctl_tcp_synack_retries;
402 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
404 void inet_csk_reqsk_queue_prune(struct sock *parent,
405 const unsigned long interval,
406 const unsigned long timeout,
407 const unsigned long max_rto)
409 struct inet_connection_sock *icsk = inet_csk(parent);
410 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
411 struct listen_sock *lopt = queue->listen_opt;
412 int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
413 int thresh = max_retries;
414 unsigned long now = jiffies;
415 struct request_sock **reqp, *req;
416 int i, budget;
418 if (lopt == NULL || lopt->qlen == 0)
419 return;
421 /* Normally all the openreqs are young and become mature
422 * (i.e. converted to established socket) for first timeout.
423 * If synack was not acknowledged for 3 seconds, it means
424 * one of the following things: synack was lost, ack was lost,
425 * rtt is high or nobody planned to ack (i.e. synflood).
426 * When server is a bit loaded, queue is populated with old
427 * open requests, reducing effective size of queue.
428 * When server is well loaded, queue size reduces to zero
429 * after several minutes of work. It is not synflood,
430 * it is normal operation. The solution is pruning
431 * too old entries overriding normal timeout, when
432 * situation becomes dangerous.
434 * Essentially, we reserve half of room for young
435 * embrions; and abort old ones without pity, if old
436 * ones are about to clog our table.
438 if (lopt->qlen>>(lopt->max_qlen_log-1)) {
439 int young = (lopt->qlen_young<<1);
441 while (thresh > 2) {
442 if (lopt->qlen < young)
443 break;
444 thresh--;
445 young <<= 1;
449 if (queue->rskq_defer_accept)
450 max_retries = queue->rskq_defer_accept;
452 budget = 2 * (lopt->nr_table_entries / (timeout / interval));
453 i = lopt->clock_hand;
455 do {
456 reqp=&lopt->syn_table[i];
457 while ((req = *reqp) != NULL) {
458 if (time_after_eq(now, req->expires)) {
459 if ((req->retrans < thresh ||
460 (inet_rsk(req)->acked && req->retrans < max_retries))
461 && !req->rsk_ops->rtx_syn_ack(parent, req, NULL)) {
462 unsigned long timeo;
464 if (req->retrans++ == 0)
465 lopt->qlen_young--;
466 timeo = min((timeout << req->retrans), max_rto);
467 req->expires = now + timeo;
468 reqp = &req->dl_next;
469 continue;
472 /* Drop this request */
473 inet_csk_reqsk_queue_unlink(parent, req, reqp);
474 reqsk_queue_removed(queue, req);
475 reqsk_free(req);
476 continue;
478 reqp = &req->dl_next;
481 i = (i + 1) & (lopt->nr_table_entries - 1);
483 } while (--budget > 0);
485 lopt->clock_hand = i;
487 if (lopt->qlen)
488 inet_csk_reset_keepalive_timer(parent, interval);
491 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
493 struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req,
494 const gfp_t priority)
496 struct sock *newsk = sk_clone(sk, priority);
498 if (newsk != NULL) {
499 struct inet_connection_sock *newicsk = inet_csk(newsk);
501 newsk->sk_state = TCP_SYN_RECV;
502 newicsk->icsk_bind_hash = NULL;
504 inet_sk(newsk)->dport = inet_rsk(req)->rmt_port;
505 newsk->sk_write_space = sk_stream_write_space;
507 newicsk->icsk_retransmits = 0;
508 newicsk->icsk_backoff = 0;
509 newicsk->icsk_probes_out = 0;
511 /* Deinitialize accept_queue to trap illegal accesses. */
512 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
514 security_inet_csk_clone(newsk, req);
516 return newsk;
519 EXPORT_SYMBOL_GPL(inet_csk_clone);
522 * At this point, there should be no process reference to this
523 * socket, and thus no user references at all. Therefore we
524 * can assume the socket waitqueue is inactive and nobody will
525 * try to jump onto it.
527 void inet_csk_destroy_sock(struct sock *sk)
529 BUG_TRAP(sk->sk_state == TCP_CLOSE);
530 BUG_TRAP(sock_flag(sk, SOCK_DEAD));
532 /* It cannot be in hash table! */
533 BUG_TRAP(sk_unhashed(sk));
535 /* If it has not 0 inet_sk(sk)->num, it must be bound */
536 BUG_TRAP(!inet_sk(sk)->num || inet_csk(sk)->icsk_bind_hash);
538 sk->sk_prot->destroy(sk);
540 sk_stream_kill_queues(sk);
542 xfrm_sk_free_policy(sk);
544 sk_refcnt_debug_release(sk);
546 atomic_dec(sk->sk_prot->orphan_count);
547 sock_put(sk);
550 EXPORT_SYMBOL(inet_csk_destroy_sock);
552 int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
554 struct inet_sock *inet = inet_sk(sk);
555 struct inet_connection_sock *icsk = inet_csk(sk);
556 int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
558 if (rc != 0)
559 return rc;
561 sk->sk_max_ack_backlog = 0;
562 sk->sk_ack_backlog = 0;
563 inet_csk_delack_init(sk);
565 /* There is race window here: we announce ourselves listening,
566 * but this transition is still not validated by get_port().
567 * It is OK, because this socket enters to hash table only
568 * after validation is complete.
570 sk->sk_state = TCP_LISTEN;
571 if (!sk->sk_prot->get_port(sk, inet->num)) {
572 inet->sport = htons(inet->num);
574 sk_dst_reset(sk);
575 sk->sk_prot->hash(sk);
577 return 0;
580 sk->sk_state = TCP_CLOSE;
581 __reqsk_queue_destroy(&icsk->icsk_accept_queue);
582 return -EADDRINUSE;
585 EXPORT_SYMBOL_GPL(inet_csk_listen_start);
588 * This routine closes sockets which have been at least partially
589 * opened, but not yet accepted.
591 void inet_csk_listen_stop(struct sock *sk)
593 struct inet_connection_sock *icsk = inet_csk(sk);
594 struct request_sock *acc_req;
595 struct request_sock *req;
597 inet_csk_delete_keepalive_timer(sk);
599 /* make all the listen_opt local to us */
600 acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue);
602 /* Following specs, it would be better either to send FIN
603 * (and enter FIN-WAIT-1, it is normal close)
604 * or to send active reset (abort).
605 * Certainly, it is pretty dangerous while synflood, but it is
606 * bad justification for our negligence 8)
607 * To be honest, we are not able to make either
608 * of the variants now. --ANK
610 reqsk_queue_destroy(&icsk->icsk_accept_queue);
612 while ((req = acc_req) != NULL) {
613 struct sock *child = req->sk;
615 acc_req = req->dl_next;
617 local_bh_disable();
618 bh_lock_sock(child);
619 BUG_TRAP(!sock_owned_by_user(child));
620 sock_hold(child);
622 sk->sk_prot->disconnect(child, O_NONBLOCK);
624 sock_orphan(child);
626 atomic_inc(sk->sk_prot->orphan_count);
628 inet_csk_destroy_sock(child);
630 bh_unlock_sock(child);
631 local_bh_enable();
632 sock_put(child);
634 sk_acceptq_removed(sk);
635 __reqsk_free(req);
637 BUG_TRAP(!sk->sk_ack_backlog);
640 EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
642 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
644 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
645 const struct inet_sock *inet = inet_sk(sk);
647 sin->sin_family = AF_INET;
648 sin->sin_addr.s_addr = inet->daddr;
649 sin->sin_port = inet->dport;
652 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
654 int inet_csk_ctl_sock_create(struct socket **sock, unsigned short family,
655 unsigned short type, unsigned char protocol)
657 int rc = sock_create_kern(family, type, protocol, sock);
659 if (rc == 0) {
660 (*sock)->sk->sk_allocation = GFP_ATOMIC;
661 inet_sk((*sock)->sk)->uc_ttl = -1;
663 * Unhash it so that IP input processing does not even see it,
664 * we do not wish this socket to see incoming packets.
666 (*sock)->sk->sk_prot->unhash((*sock)->sk);
668 return rc;
671 EXPORT_SYMBOL_GPL(inet_csk_ctl_sock_create);
673 #ifdef CONFIG_COMPAT
674 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
675 char __user *optval, int __user *optlen)
677 const struct inet_connection_sock *icsk = inet_csk(sk);
679 if (icsk->icsk_af_ops->compat_getsockopt != NULL)
680 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
681 optval, optlen);
682 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
683 optval, optlen);
686 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
688 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
689 char __user *optval, int optlen)
691 const struct inet_connection_sock *icsk = inet_csk(sk);
693 if (icsk->icsk_af_ops->compat_setsockopt != NULL)
694 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
695 optval, optlen);
696 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
697 optval, optlen);
700 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
701 #endif