[ICSK]: make inet_csk_reqsk_queue_hash_add timeout arg unsigned long
[linux-2.6] / net / ipv4 / inet_connection_sock.c
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/config.h>
17 #include <linux/module.h>
18 #include <linux/jhash.h>
19
20 #include <net/inet_connection_sock.h>
21 #include <net/inet_hashtables.h>
22 #include <net/inet_timewait_sock.h>
23 #include <net/ip.h>
24 #include <net/route.h>
25 #include <net/tcp_states.h>
26 #include <net/xfrm.h>
27
28 #ifdef INET_CSK_DEBUG
29 const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
30 EXPORT_SYMBOL(inet_csk_timer_bug_msg);
31 #endif
32
33 /*
34  * This array holds the first and last local port number.
35  * For high-usage systems, use sysctl to change this to
36  * 32768-61000
37  */
38 int sysctl_local_port_range[2] = { 1024, 4999 };
39
40 int inet_csk_bind_conflict(const struct sock *sk,
41                            const struct inet_bind_bucket *tb)
42 {
43         const u32 sk_rcv_saddr = inet_rcv_saddr(sk);
44         struct sock *sk2;
45         struct hlist_node *node;
46         int reuse = sk->sk_reuse;
47
48         sk_for_each_bound(sk2, node, &tb->owners) {
49                 if (sk != sk2 &&
50                     !inet_v6_ipv6only(sk2) &&
51                     (!sk->sk_bound_dev_if ||
52                      !sk2->sk_bound_dev_if ||
53                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
54                         if (!reuse || !sk2->sk_reuse ||
55                             sk2->sk_state == TCP_LISTEN) {
56                                 const u32 sk2_rcv_saddr = inet_rcv_saddr(sk2);
57                                 if (!sk2_rcv_saddr || !sk_rcv_saddr ||
58                                     sk2_rcv_saddr == sk_rcv_saddr)
59                                         break;
60                         }
61                 }
62         }
63         return node != NULL;
64 }
65
66 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
67
68 /* Obtain a reference to a local port for the given sock,
69  * if snum is zero it means select any available local port.
70  */
71 int inet_csk_get_port(struct inet_hashinfo *hashinfo,
72                       struct sock *sk, unsigned short snum,
73                       int (*bind_conflict)(const struct sock *sk,
74                                            const struct inet_bind_bucket *tb))
75 {
76         struct inet_bind_hashbucket *head;
77         struct hlist_node *node;
78         struct inet_bind_bucket *tb;
79         int ret;
80
81         local_bh_disable();
82         if (!snum) {
83                 int low = sysctl_local_port_range[0];
84                 int high = sysctl_local_port_range[1];
85                 int remaining = (high - low) + 1;
86                 int rover = net_random() % (high - low) + low;
87
88                 do {
89                         head = &hashinfo->bhash[inet_bhashfn(rover, hashinfo->bhash_size)];
90                         spin_lock(&head->lock);
91                         inet_bind_bucket_for_each(tb, node, &head->chain)
92                                 if (tb->port == rover)
93                                         goto next;
94                         break;
95                 next:
96                         spin_unlock(&head->lock);
97                         if (++rover > high)
98                                 rover = low;
99                 } while (--remaining > 0);
100
101                 /* Exhausted local port range during search?  It is not
102                  * possible for us to be holding one of the bind hash
103                  * locks if this test triggers, because if 'remaining'
104                  * drops to zero, we broke out of the do/while loop at
105                  * the top level, not from the 'break;' statement.
106                  */
107                 ret = 1;
108                 if (remaining <= 0)
109                         goto fail;
110
111                 /* OK, here is the one we will use.  HEAD is
112                  * non-NULL and we hold it's mutex.
113                  */
114                 snum = rover;
115         } else {
116                 head = &hashinfo->bhash[inet_bhashfn(snum, hashinfo->bhash_size)];
117                 spin_lock(&head->lock);
118                 inet_bind_bucket_for_each(tb, node, &head->chain)
119                         if (tb->port == snum)
120                                 goto tb_found;
121         }
122         tb = NULL;
123         goto tb_not_found;
124 tb_found:
125         if (!hlist_empty(&tb->owners)) {
126                 if (sk->sk_reuse > 1)
127                         goto success;
128                 if (tb->fastreuse > 0 &&
129                     sk->sk_reuse && sk->sk_state != TCP_LISTEN) {
130                         goto success;
131                 } else {
132                         ret = 1;
133                         if (bind_conflict(sk, tb))
134                                 goto fail_unlock;
135                 }
136         }
137 tb_not_found:
138         ret = 1;
139         if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep, head, snum)) == NULL)
140                 goto fail_unlock;
141         if (hlist_empty(&tb->owners)) {
142                 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
143                         tb->fastreuse = 1;
144                 else
145                         tb->fastreuse = 0;
146         } else if (tb->fastreuse &&
147                    (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
148                 tb->fastreuse = 0;
149 success:
150         if (!inet_csk(sk)->icsk_bind_hash)
151                 inet_bind_hash(sk, tb, snum);
152         BUG_TRAP(inet_csk(sk)->icsk_bind_hash == tb);
153         ret = 0;
154
155 fail_unlock:
156         spin_unlock(&head->lock);
157 fail:
158         local_bh_enable();
159         return ret;
160 }
161
162 EXPORT_SYMBOL_GPL(inet_csk_get_port);
163
164 /*
165  * Wait for an incoming connection, avoid race conditions. This must be called
166  * with the socket locked.
167  */
168 static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
169 {
170         struct inet_connection_sock *icsk = inet_csk(sk);
171         DEFINE_WAIT(wait);
172         int err;
173
174         /*
175          * True wake-one mechanism for incoming connections: only
176          * one process gets woken up, not the 'whole herd'.
177          * Since we do not 'race & poll' for established sockets
178          * anymore, the common case will execute the loop only once.
179          *
180          * Subtle issue: "add_wait_queue_exclusive()" will be added
181          * after any current non-exclusive waiters, and we know that
182          * it will always _stay_ after any new non-exclusive waiters
183          * because all non-exclusive waiters are added at the
184          * beginning of the wait-queue. As such, it's ok to "drop"
185          * our exclusiveness temporarily when we get woken up without
186          * having to remove and re-insert us on the wait queue.
187          */
188         for (;;) {
189                 prepare_to_wait_exclusive(sk->sk_sleep, &wait,
190                                           TASK_INTERRUPTIBLE);
191                 release_sock(sk);
192                 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
193                         timeo = schedule_timeout(timeo);
194                 lock_sock(sk);
195                 err = 0;
196                 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
197                         break;
198                 err = -EINVAL;
199                 if (sk->sk_state != TCP_LISTEN)
200                         break;
201                 err = sock_intr_errno(timeo);
202                 if (signal_pending(current))
203                         break;
204                 err = -EAGAIN;
205                 if (!timeo)
206                         break;
207         }
208         finish_wait(sk->sk_sleep, &wait);
209         return err;
210 }
211
212 /*
213  * This will accept the next outstanding connection.
214  */
215 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
216 {
217         struct inet_connection_sock *icsk = inet_csk(sk);
218         struct sock *newsk;
219         int error;
220
221         lock_sock(sk);
222
223         /* We need to make sure that this socket is listening,
224          * and that it has something pending.
225          */
226         error = -EINVAL;
227         if (sk->sk_state != TCP_LISTEN)
228                 goto out_err;
229
230         /* Find already established connection */
231         if (reqsk_queue_empty(&icsk->icsk_accept_queue)) {
232                 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
233
234                 /* If this is a non blocking socket don't sleep */
235                 error = -EAGAIN;
236                 if (!timeo)
237                         goto out_err;
238
239                 error = inet_csk_wait_for_connect(sk, timeo);
240                 if (error)
241                         goto out_err;
242         }
243
244         newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
245         BUG_TRAP(newsk->sk_state != TCP_SYN_RECV);
246 out:
247         release_sock(sk);
248         return newsk;
249 out_err:
250         newsk = NULL;
251         *err = error;
252         goto out;
253 }
254
255 EXPORT_SYMBOL(inet_csk_accept);
256
257 /*
258  * Using different timers for retransmit, delayed acks and probes
259  * We may wish use just one timer maintaining a list of expire jiffies 
260  * to optimize.
261  */
262 void inet_csk_init_xmit_timers(struct sock *sk,
263                                void (*retransmit_handler)(unsigned long),
264                                void (*delack_handler)(unsigned long),
265                                void (*keepalive_handler)(unsigned long))
266 {
267         struct inet_connection_sock *icsk = inet_csk(sk);
268
269         init_timer(&icsk->icsk_retransmit_timer);
270         init_timer(&icsk->icsk_delack_timer);
271         init_timer(&sk->sk_timer);
272
273         icsk->icsk_retransmit_timer.function = retransmit_handler;
274         icsk->icsk_delack_timer.function     = delack_handler;
275         sk->sk_timer.function                = keepalive_handler;
276
277         icsk->icsk_retransmit_timer.data = 
278                 icsk->icsk_delack_timer.data =
279                         sk->sk_timer.data  = (unsigned long)sk;
280
281         icsk->icsk_pending = icsk->icsk_ack.pending = 0;
282 }
283
284 EXPORT_SYMBOL(inet_csk_init_xmit_timers);
285
286 void inet_csk_clear_xmit_timers(struct sock *sk)
287 {
288         struct inet_connection_sock *icsk = inet_csk(sk);
289
290         icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
291
292         sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
293         sk_stop_timer(sk, &icsk->icsk_delack_timer);
294         sk_stop_timer(sk, &sk->sk_timer);
295 }
296
297 EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
298
299 void inet_csk_delete_keepalive_timer(struct sock *sk)
300 {
301         sk_stop_timer(sk, &sk->sk_timer);
302 }
303
304 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
305
306 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
307 {
308         sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
309 }
310
311 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
312
313 struct dst_entry* inet_csk_route_req(struct sock *sk,
314                                      const struct request_sock *req)
315 {
316         struct rtable *rt;
317         const struct inet_request_sock *ireq = inet_rsk(req);
318         struct ip_options *opt = inet_rsk(req)->opt;
319         struct flowi fl = { .oif = sk->sk_bound_dev_if,
320                             .nl_u = { .ip4_u =
321                                       { .daddr = ((opt && opt->srr) ?
322                                                   opt->faddr :
323                                                   ireq->rmt_addr),
324                                         .saddr = ireq->loc_addr,
325                                         .tos = RT_CONN_FLAGS(sk) } },
326                             .proto = sk->sk_protocol,
327                             .uli_u = { .ports =
328                                        { .sport = inet_sk(sk)->sport,
329                                          .dport = ireq->rmt_port } } };
330
331         if (ip_route_output_flow(&rt, &fl, sk, 0)) {
332                 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
333                 return NULL;
334         }
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;
339         }
340         return &rt->u.dst;
341 }
342
343 EXPORT_SYMBOL_GPL(inet_csk_route_req);
344
345 static inline u32 inet_synq_hash(const u32 raddr, const u16 rport,
346                                  const u32 rnd, const u16 synq_hsize)
347 {
348         return jhash_2words(raddr, (u32)rport, rnd) & (synq_hsize - 1);
349 }
350
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
356
357 struct request_sock *inet_csk_search_req(const struct sock *sk,
358                                          struct request_sock ***prevp,
359                                          const __u16 rport, const __u32 raddr,
360                                          const __u32 laddr)
361 {
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;
365
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);
371
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;
379                 }
380         }
381
382         return req;
383 }
384
385 EXPORT_SYMBOL_GPL(inet_csk_search_req);
386
387 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
388                                    unsigned long timeout)
389 {
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);
394
395         reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
396         inet_csk_reqsk_queue_added(sk, timeout);
397 }
398
399 /* Only thing we need from tcp.h */
400 extern int sysctl_tcp_synack_retries;
401
402 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
403
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)
408 {
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;
417
418         if (lopt == NULL || lopt->qlen == 0)
419                 return;
420
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.
433          *
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.
437          */
438         if (lopt->qlen>>(lopt->max_qlen_log-1)) {
439                 int young = (lopt->qlen_young<<1);
440
441                 while (thresh > 2) {
442                         if (lopt->qlen < young)
443                                 break;
444                         thresh--;
445                         young <<= 1;
446                 }
447         }
448
449         if (queue->rskq_defer_accept)
450                 max_retries = queue->rskq_defer_accept;
451
452         budget = 2 * (lopt->nr_table_entries / (timeout / interval));
453         i = lopt->clock_hand;
454
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;
463
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;
470                                 }
471
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;
477                         }
478                         reqp = &req->dl_next;
479                 }
480
481                 i = (i + 1) & (lopt->nr_table_entries - 1);
482
483         } while (--budget > 0);
484
485         lopt->clock_hand = i;
486
487         if (lopt->qlen)
488                 inet_csk_reset_keepalive_timer(parent, interval);
489 }
490
491 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
492
493 struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req,
494                             const gfp_t priority)
495 {
496         struct sock *newsk = sk_clone(sk, priority);
497
498         if (newsk != NULL) {
499                 struct inet_connection_sock *newicsk = inet_csk(newsk);
500
501                 newsk->sk_state = TCP_SYN_RECV;
502                 newicsk->icsk_bind_hash = NULL;
503
504                 inet_sk(newsk)->dport = inet_rsk(req)->rmt_port;
505                 newsk->sk_write_space = sk_stream_write_space;
506
507                 newicsk->icsk_retransmits = 0;
508                 newicsk->icsk_backoff     = 0;
509                 newicsk->icsk_probes_out  = 0;
510
511                 /* Deinitialize accept_queue to trap illegal accesses. */
512                 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
513         }
514         return newsk;
515 }
516
517 EXPORT_SYMBOL_GPL(inet_csk_clone);
518
519 /*
520  * At this point, there should be no process reference to this
521  * socket, and thus no user references at all.  Therefore we
522  * can assume the socket waitqueue is inactive and nobody will
523  * try to jump onto it.
524  */
525 void inet_csk_destroy_sock(struct sock *sk)
526 {
527         BUG_TRAP(sk->sk_state == TCP_CLOSE);
528         BUG_TRAP(sock_flag(sk, SOCK_DEAD));
529
530         /* It cannot be in hash table! */
531         BUG_TRAP(sk_unhashed(sk));
532
533         /* If it has not 0 inet_sk(sk)->num, it must be bound */
534         BUG_TRAP(!inet_sk(sk)->num || inet_csk(sk)->icsk_bind_hash);
535
536         sk->sk_prot->destroy(sk);
537
538         sk_stream_kill_queues(sk);
539
540         xfrm_sk_free_policy(sk);
541
542         sk_refcnt_debug_release(sk);
543
544         atomic_dec(sk->sk_prot->orphan_count);
545         sock_put(sk);
546 }
547
548 EXPORT_SYMBOL(inet_csk_destroy_sock);
549
550 int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
551 {
552         struct inet_sock *inet = inet_sk(sk);
553         struct inet_connection_sock *icsk = inet_csk(sk);
554         int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
555
556         if (rc != 0)
557                 return rc;
558
559         sk->sk_max_ack_backlog = 0;
560         sk->sk_ack_backlog = 0;
561         inet_csk_delack_init(sk);
562
563         /* There is race window here: we announce ourselves listening,
564          * but this transition is still not validated by get_port().
565          * It is OK, because this socket enters to hash table only
566          * after validation is complete.
567          */
568         sk->sk_state = TCP_LISTEN;
569         if (!sk->sk_prot->get_port(sk, inet->num)) {
570                 inet->sport = htons(inet->num);
571
572                 sk_dst_reset(sk);
573                 sk->sk_prot->hash(sk);
574
575                 return 0;
576         }
577
578         sk->sk_state = TCP_CLOSE;
579         __reqsk_queue_destroy(&icsk->icsk_accept_queue);
580         return -EADDRINUSE;
581 }
582
583 EXPORT_SYMBOL_GPL(inet_csk_listen_start);
584
585 /*
586  *      This routine closes sockets which have been at least partially
587  *      opened, but not yet accepted.
588  */
589 void inet_csk_listen_stop(struct sock *sk)
590 {
591         struct inet_connection_sock *icsk = inet_csk(sk);
592         struct request_sock *acc_req;
593         struct request_sock *req;
594
595         inet_csk_delete_keepalive_timer(sk);
596
597         /* make all the listen_opt local to us */
598         acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue);
599
600         /* Following specs, it would be better either to send FIN
601          * (and enter FIN-WAIT-1, it is normal close)
602          * or to send active reset (abort).
603          * Certainly, it is pretty dangerous while synflood, but it is
604          * bad justification for our negligence 8)
605          * To be honest, we are not able to make either
606          * of the variants now.                 --ANK
607          */
608         reqsk_queue_destroy(&icsk->icsk_accept_queue);
609
610         while ((req = acc_req) != NULL) {
611                 struct sock *child = req->sk;
612
613                 acc_req = req->dl_next;
614
615                 local_bh_disable();
616                 bh_lock_sock(child);
617                 BUG_TRAP(!sock_owned_by_user(child));
618                 sock_hold(child);
619
620                 sk->sk_prot->disconnect(child, O_NONBLOCK);
621
622                 sock_orphan(child);
623
624                 atomic_inc(sk->sk_prot->orphan_count);
625
626                 inet_csk_destroy_sock(child);
627
628                 bh_unlock_sock(child);
629                 local_bh_enable();
630                 sock_put(child);
631
632                 sk_acceptq_removed(sk);
633                 __reqsk_free(req);
634         }
635         BUG_TRAP(!sk->sk_ack_backlog);
636 }
637
638 EXPORT_SYMBOL_GPL(inet_csk_listen_stop);