ipv4: fix multicast losses
[linux-2.6.git] / 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/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
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
31
32 /*
33  * This struct holds the first and last local port number.
34  */
35 struct local_ports sysctl_local_ports __read_mostly = {
36         .lock = __SEQLOCK_UNLOCKED(sysctl_local_ports.lock),
37         .range = { 32768, 61000 },
38 };
39
40 unsigned long *sysctl_local_reserved_ports;
41 EXPORT_SYMBOL(sysctl_local_reserved_ports);
42
43 void inet_get_local_port_range(int *low, int *high)
44 {
45         unsigned seq;
46         do {
47                 seq = read_seqbegin(&sysctl_local_ports.lock);
48
49                 *low = sysctl_local_ports.range[0];
50                 *high = sysctl_local_ports.range[1];
51         } while (read_seqretry(&sysctl_local_ports.lock, seq));
52 }
53 EXPORT_SYMBOL(inet_get_local_port_range);
54
55 int inet_csk_bind_conflict(const struct sock *sk,
56                            const struct inet_bind_bucket *tb)
57 {
58         struct sock *sk2;
59         struct hlist_node *node;
60         int reuse = sk->sk_reuse;
61
62         /*
63          * Unlike other sk lookup places we do not check
64          * for sk_net here, since _all_ the socks listed
65          * in tb->owners list belong to the same net - the
66          * one this bucket belongs to.
67          */
68
69         sk_for_each_bound(sk2, node, &tb->owners) {
70                 if (sk != sk2 &&
71                     !inet_v6_ipv6only(sk2) &&
72                     (!sk->sk_bound_dev_if ||
73                      !sk2->sk_bound_dev_if ||
74                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
75                         if (!reuse || !sk2->sk_reuse ||
76                             sk2->sk_state == TCP_LISTEN) {
77                                 const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
78                                 if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||
79                                     sk2_rcv_saddr == sk_rcv_saddr(sk))
80                                         break;
81                         }
82                 }
83         }
84         return node != NULL;
85 }
86 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
87
88 /* Obtain a reference to a local port for the given sock,
89  * if snum is zero it means select any available local port.
90  */
91 int inet_csk_get_port(struct sock *sk, unsigned short snum)
92 {
93         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
94         struct inet_bind_hashbucket *head;
95         struct hlist_node *node;
96         struct inet_bind_bucket *tb;
97         int ret, attempts = 5;
98         struct net *net = sock_net(sk);
99         int smallest_size = -1, smallest_rover;
100
101         local_bh_disable();
102         if (!snum) {
103                 int remaining, rover, low, high;
104
105 again:
106                 inet_get_local_port_range(&low, &high);
107                 remaining = (high - low) + 1;
108                 smallest_rover = rover = net_random() % remaining + low;
109
110                 smallest_size = -1;
111                 do {
112                         if (inet_is_reserved_local_port(rover))
113                                 goto next_nolock;
114                         head = &hashinfo->bhash[inet_bhashfn(net, rover,
115                                         hashinfo->bhash_size)];
116                         spin_lock(&head->lock);
117                         inet_bind_bucket_for_each(tb, node, &head->chain)
118                                 if (net_eq(ib_net(tb), net) && tb->port == rover) {
119                                         if (tb->fastreuse > 0 &&
120                                             sk->sk_reuse &&
121                                             sk->sk_state != TCP_LISTEN &&
122                                             (tb->num_owners < smallest_size || smallest_size == -1)) {
123                                                 smallest_size = tb->num_owners;
124                                                 smallest_rover = rover;
125                                                 if (atomic_read(&hashinfo->bsockets) > (high - low) + 1) {
126                                                         spin_unlock(&head->lock);
127                                                         snum = smallest_rover;
128                                                         goto have_snum;
129                                                 }
130                                         }
131                                         goto next;
132                                 }
133                         break;
134                 next:
135                         spin_unlock(&head->lock);
136                 next_nolock:
137                         if (++rover > high)
138                                 rover = low;
139                 } while (--remaining > 0);
140
141                 /* Exhausted local port range during search?  It is not
142                  * possible for us to be holding one of the bind hash
143                  * locks if this test triggers, because if 'remaining'
144                  * drops to zero, we broke out of the do/while loop at
145                  * the top level, not from the 'break;' statement.
146                  */
147                 ret = 1;
148                 if (remaining <= 0) {
149                         if (smallest_size != -1) {
150                                 snum = smallest_rover;
151                                 goto have_snum;
152                         }
153                         goto fail;
154                 }
155                 /* OK, here is the one we will use.  HEAD is
156                  * non-NULL and we hold it's mutex.
157                  */
158                 snum = rover;
159         } else {
160 have_snum:
161                 head = &hashinfo->bhash[inet_bhashfn(net, snum,
162                                 hashinfo->bhash_size)];
163                 spin_lock(&head->lock);
164                 inet_bind_bucket_for_each(tb, node, &head->chain)
165                         if (net_eq(ib_net(tb), net) && tb->port == snum)
166                                 goto tb_found;
167         }
168         tb = NULL;
169         goto tb_not_found;
170 tb_found:
171         if (!hlist_empty(&tb->owners)) {
172                 if (tb->fastreuse > 0 &&
173                     sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
174                     smallest_size == -1) {
175                         goto success;
176                 } else {
177                         ret = 1;
178                         if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb)) {
179                                 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
180                                     smallest_size != -1 && --attempts >= 0) {
181                                         spin_unlock(&head->lock);
182                                         goto again;
183                                 }
184                                 goto fail_unlock;
185                         }
186                 }
187         }
188 tb_not_found:
189         ret = 1;
190         if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
191                                         net, head, snum)) == NULL)
192                 goto fail_unlock;
193         if (hlist_empty(&tb->owners)) {
194                 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
195                         tb->fastreuse = 1;
196                 else
197                         tb->fastreuse = 0;
198         } else if (tb->fastreuse &&
199                    (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
200                 tb->fastreuse = 0;
201 success:
202         if (!inet_csk(sk)->icsk_bind_hash)
203                 inet_bind_hash(sk, tb, snum);
204         WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
205         ret = 0;
206
207 fail_unlock:
208         spin_unlock(&head->lock);
209 fail:
210         local_bh_enable();
211         return ret;
212 }
213 EXPORT_SYMBOL_GPL(inet_csk_get_port);
214
215 /*
216  * Wait for an incoming connection, avoid race conditions. This must be called
217  * with the socket locked.
218  */
219 static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
220 {
221         struct inet_connection_sock *icsk = inet_csk(sk);
222         DEFINE_WAIT(wait);
223         int err;
224
225         /*
226          * True wake-one mechanism for incoming connections: only
227          * one process gets woken up, not the 'whole herd'.
228          * Since we do not 'race & poll' for established sockets
229          * anymore, the common case will execute the loop only once.
230          *
231          * Subtle issue: "add_wait_queue_exclusive()" will be added
232          * after any current non-exclusive waiters, and we know that
233          * it will always _stay_ after any new non-exclusive waiters
234          * because all non-exclusive waiters are added at the
235          * beginning of the wait-queue. As such, it's ok to "drop"
236          * our exclusiveness temporarily when we get woken up without
237          * having to remove and re-insert us on the wait queue.
238          */
239         for (;;) {
240                 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
241                                           TASK_INTERRUPTIBLE);
242                 release_sock(sk);
243                 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
244                         timeo = schedule_timeout(timeo);
245                 lock_sock(sk);
246                 err = 0;
247                 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
248                         break;
249                 err = -EINVAL;
250                 if (sk->sk_state != TCP_LISTEN)
251                         break;
252                 err = sock_intr_errno(timeo);
253                 if (signal_pending(current))
254                         break;
255                 err = -EAGAIN;
256                 if (!timeo)
257                         break;
258         }
259         finish_wait(sk_sleep(sk), &wait);
260         return err;
261 }
262
263 /*
264  * This will accept the next outstanding connection.
265  */
266 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
267 {
268         struct inet_connection_sock *icsk = inet_csk(sk);
269         struct sock *newsk;
270         int error;
271
272         lock_sock(sk);
273
274         /* We need to make sure that this socket is listening,
275          * and that it has something pending.
276          */
277         error = -EINVAL;
278         if (sk->sk_state != TCP_LISTEN)
279                 goto out_err;
280
281         /* Find already established connection */
282         if (reqsk_queue_empty(&icsk->icsk_accept_queue)) {
283                 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
284
285                 /* If this is a non blocking socket don't sleep */
286                 error = -EAGAIN;
287                 if (!timeo)
288                         goto out_err;
289
290                 error = inet_csk_wait_for_connect(sk, timeo);
291                 if (error)
292                         goto out_err;
293         }
294
295         newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
296         WARN_ON(newsk->sk_state == TCP_SYN_RECV);
297 out:
298         release_sock(sk);
299         return newsk;
300 out_err:
301         newsk = NULL;
302         *err = error;
303         goto out;
304 }
305 EXPORT_SYMBOL(inet_csk_accept);
306
307 /*
308  * Using different timers for retransmit, delayed acks and probes
309  * We may wish use just one timer maintaining a list of expire jiffies
310  * to optimize.
311  */
312 void inet_csk_init_xmit_timers(struct sock *sk,
313                                void (*retransmit_handler)(unsigned long),
314                                void (*delack_handler)(unsigned long),
315                                void (*keepalive_handler)(unsigned long))
316 {
317         struct inet_connection_sock *icsk = inet_csk(sk);
318
319         setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
320                         (unsigned long)sk);
321         setup_timer(&icsk->icsk_delack_timer, delack_handler,
322                         (unsigned long)sk);
323         setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
324         icsk->icsk_pending = icsk->icsk_ack.pending = 0;
325 }
326 EXPORT_SYMBOL(inet_csk_init_xmit_timers);
327
328 void inet_csk_clear_xmit_timers(struct sock *sk)
329 {
330         struct inet_connection_sock *icsk = inet_csk(sk);
331
332         icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
333
334         sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
335         sk_stop_timer(sk, &icsk->icsk_delack_timer);
336         sk_stop_timer(sk, &sk->sk_timer);
337 }
338 EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
339
340 void inet_csk_delete_keepalive_timer(struct sock *sk)
341 {
342         sk_stop_timer(sk, &sk->sk_timer);
343 }
344 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
345
346 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
347 {
348         sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
349 }
350 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
351
352 struct dst_entry *inet_csk_route_req(struct sock *sk,
353                                      struct flowi4 *fl4,
354                                      const struct request_sock *req)
355 {
356         struct rtable *rt;
357         const struct inet_request_sock *ireq = inet_rsk(req);
358         struct ip_options_rcu *opt = inet_rsk(req)->opt;
359         struct net *net = sock_net(sk);
360
361         flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
362                            RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
363                            sk->sk_protocol, inet_sk_flowi_flags(sk),
364                            (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr,
365                            ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport);
366         security_req_classify_flow(req, flowi4_to_flowi(fl4));
367         rt = ip_route_output_flow(net, fl4, sk);
368         if (IS_ERR(rt))
369                 goto no_route;
370         if (opt && opt->opt.is_strictroute && fl4->daddr != rt->rt_gateway)
371                 goto route_err;
372         return &rt->dst;
373
374 route_err:
375         ip_rt_put(rt);
376 no_route:
377         IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
378         return NULL;
379 }
380 EXPORT_SYMBOL_GPL(inet_csk_route_req);
381
382 struct dst_entry *inet_csk_route_child_sock(struct sock *sk,
383                                             struct sock *newsk,
384                                             const struct request_sock *req)
385 {
386         const struct inet_request_sock *ireq = inet_rsk(req);
387         struct inet_sock *newinet = inet_sk(newsk);
388         struct ip_options_rcu *opt = ireq->opt;
389         struct net *net = sock_net(sk);
390         struct flowi4 *fl4;
391         struct rtable *rt;
392
393         fl4 = &newinet->cork.fl.u.ip4;
394         flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
395                            RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
396                            sk->sk_protocol, inet_sk_flowi_flags(sk),
397                            (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr,
398                            ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport);
399         security_req_classify_flow(req, flowi4_to_flowi(fl4));
400         rt = ip_route_output_flow(net, fl4, sk);
401         if (IS_ERR(rt))
402                 goto no_route;
403         if (opt && opt->opt.is_strictroute && fl4->daddr != rt->rt_gateway)
404                 goto route_err;
405         return &rt->dst;
406
407 route_err:
408         ip_rt_put(rt);
409 no_route:
410         IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
411         return NULL;
412 }
413 EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
414
415 static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
416                                  const u32 rnd, const u32 synq_hsize)
417 {
418         return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
419 }
420
421 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
422 #define AF_INET_FAMILY(fam) ((fam) == AF_INET)
423 #else
424 #define AF_INET_FAMILY(fam) 1
425 #endif
426
427 struct request_sock *inet_csk_search_req(const struct sock *sk,
428                                          struct request_sock ***prevp,
429                                          const __be16 rport, const __be32 raddr,
430                                          const __be32 laddr)
431 {
432         const struct inet_connection_sock *icsk = inet_csk(sk);
433         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
434         struct request_sock *req, **prev;
435
436         for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd,
437                                                     lopt->nr_table_entries)];
438              (req = *prev) != NULL;
439              prev = &req->dl_next) {
440                 const struct inet_request_sock *ireq = inet_rsk(req);
441
442                 if (ireq->rmt_port == rport &&
443                     ireq->rmt_addr == raddr &&
444                     ireq->loc_addr == laddr &&
445                     AF_INET_FAMILY(req->rsk_ops->family)) {
446                         WARN_ON(req->sk);
447                         *prevp = prev;
448                         break;
449                 }
450         }
451
452         return req;
453 }
454 EXPORT_SYMBOL_GPL(inet_csk_search_req);
455
456 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
457                                    unsigned long timeout)
458 {
459         struct inet_connection_sock *icsk = inet_csk(sk);
460         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
461         const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port,
462                                      lopt->hash_rnd, lopt->nr_table_entries);
463
464         reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
465         inet_csk_reqsk_queue_added(sk, timeout);
466 }
467 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
468
469 /* Only thing we need from tcp.h */
470 extern int sysctl_tcp_synack_retries;
471
472
473 /* Decide when to expire the request and when to resend SYN-ACK */
474 static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
475                                   const int max_retries,
476                                   const u8 rskq_defer_accept,
477                                   int *expire, int *resend)
478 {
479         if (!rskq_defer_accept) {
480                 *expire = req->retrans >= thresh;
481                 *resend = 1;
482                 return;
483         }
484         *expire = req->retrans >= thresh &&
485                   (!inet_rsk(req)->acked || req->retrans >= max_retries);
486         /*
487          * Do not resend while waiting for data after ACK,
488          * start to resend on end of deferring period to give
489          * last chance for data or ACK to create established socket.
490          */
491         *resend = !inet_rsk(req)->acked ||
492                   req->retrans >= rskq_defer_accept - 1;
493 }
494
495 void inet_csk_reqsk_queue_prune(struct sock *parent,
496                                 const unsigned long interval,
497                                 const unsigned long timeout,
498                                 const unsigned long max_rto)
499 {
500         struct inet_connection_sock *icsk = inet_csk(parent);
501         struct request_sock_queue *queue = &icsk->icsk_accept_queue;
502         struct listen_sock *lopt = queue->listen_opt;
503         int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
504         int thresh = max_retries;
505         unsigned long now = jiffies;
506         struct request_sock **reqp, *req;
507         int i, budget;
508
509         if (lopt == NULL || lopt->qlen == 0)
510                 return;
511
512         /* Normally all the openreqs are young and become mature
513          * (i.e. converted to established socket) for first timeout.
514          * If synack was not acknowledged for 3 seconds, it means
515          * one of the following things: synack was lost, ack was lost,
516          * rtt is high or nobody planned to ack (i.e. synflood).
517          * When server is a bit loaded, queue is populated with old
518          * open requests, reducing effective size of queue.
519          * When server is well loaded, queue size reduces to zero
520          * after several minutes of work. It is not synflood,
521          * it is normal operation. The solution is pruning
522          * too old entries overriding normal timeout, when
523          * situation becomes dangerous.
524          *
525          * Essentially, we reserve half of room for young
526          * embrions; and abort old ones without pity, if old
527          * ones are about to clog our table.
528          */
529         if (lopt->qlen>>(lopt->max_qlen_log-1)) {
530                 int young = (lopt->qlen_young<<1);
531
532                 while (thresh > 2) {
533                         if (lopt->qlen < young)
534                                 break;
535                         thresh--;
536                         young <<= 1;
537                 }
538         }
539
540         if (queue->rskq_defer_accept)
541                 max_retries = queue->rskq_defer_accept;
542
543         budget = 2 * (lopt->nr_table_entries / (timeout / interval));
544         i = lopt->clock_hand;
545
546         do {
547                 reqp=&lopt->syn_table[i];
548                 while ((req = *reqp) != NULL) {
549                         if (time_after_eq(now, req->expires)) {
550                                 int expire = 0, resend = 0;
551
552                                 syn_ack_recalc(req, thresh, max_retries,
553                                                queue->rskq_defer_accept,
554                                                &expire, &resend);
555                                 if (req->rsk_ops->syn_ack_timeout)
556                                         req->rsk_ops->syn_ack_timeout(parent, req);
557                                 if (!expire &&
558                                     (!resend ||
559                                      !req->rsk_ops->rtx_syn_ack(parent, req, NULL) ||
560                                      inet_rsk(req)->acked)) {
561                                         unsigned long timeo;
562
563                                         if (req->retrans++ == 0)
564                                                 lopt->qlen_young--;
565                                         timeo = min((timeout << req->retrans), max_rto);
566                                         req->expires = now + timeo;
567                                         reqp = &req->dl_next;
568                                         continue;
569                                 }
570
571                                 /* Drop this request */
572                                 inet_csk_reqsk_queue_unlink(parent, req, reqp);
573                                 reqsk_queue_removed(queue, req);
574                                 reqsk_free(req);
575                                 continue;
576                         }
577                         reqp = &req->dl_next;
578                 }
579
580                 i = (i + 1) & (lopt->nr_table_entries - 1);
581
582         } while (--budget > 0);
583
584         lopt->clock_hand = i;
585
586         if (lopt->qlen)
587                 inet_csk_reset_keepalive_timer(parent, interval);
588 }
589 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
590
591 struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req,
592                             const gfp_t priority)
593 {
594         struct sock *newsk = sk_clone(sk, priority);
595
596         if (newsk != NULL) {
597                 struct inet_connection_sock *newicsk = inet_csk(newsk);
598
599                 newsk->sk_state = TCP_SYN_RECV;
600                 newicsk->icsk_bind_hash = NULL;
601
602                 inet_sk(newsk)->inet_dport = inet_rsk(req)->rmt_port;
603                 inet_sk(newsk)->inet_num = ntohs(inet_rsk(req)->loc_port);
604                 inet_sk(newsk)->inet_sport = inet_rsk(req)->loc_port;
605                 newsk->sk_write_space = sk_stream_write_space;
606
607                 newicsk->icsk_retransmits = 0;
608                 newicsk->icsk_backoff     = 0;
609                 newicsk->icsk_probes_out  = 0;
610
611                 /* Deinitialize accept_queue to trap illegal accesses. */
612                 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
613
614                 security_inet_csk_clone(newsk, req);
615         }
616         return newsk;
617 }
618 EXPORT_SYMBOL_GPL(inet_csk_clone);
619
620 /*
621  * At this point, there should be no process reference to this
622  * socket, and thus no user references at all.  Therefore we
623  * can assume the socket waitqueue is inactive and nobody will
624  * try to jump onto it.
625  */
626 void inet_csk_destroy_sock(struct sock *sk)
627 {
628         WARN_ON(sk->sk_state != TCP_CLOSE);
629         WARN_ON(!sock_flag(sk, SOCK_DEAD));
630
631         /* It cannot be in hash table! */
632         WARN_ON(!sk_unhashed(sk));
633
634         /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
635         WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
636
637         sk->sk_prot->destroy(sk);
638
639         sk_stream_kill_queues(sk);
640
641         xfrm_sk_free_policy(sk);
642
643         sk_refcnt_debug_release(sk);
644
645         percpu_counter_dec(sk->sk_prot->orphan_count);
646         sock_put(sk);
647 }
648 EXPORT_SYMBOL(inet_csk_destroy_sock);
649
650 int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
651 {
652         struct inet_sock *inet = inet_sk(sk);
653         struct inet_connection_sock *icsk = inet_csk(sk);
654         int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
655
656         if (rc != 0)
657                 return rc;
658
659         sk->sk_max_ack_backlog = 0;
660         sk->sk_ack_backlog = 0;
661         inet_csk_delack_init(sk);
662
663         /* There is race window here: we announce ourselves listening,
664          * but this transition is still not validated by get_port().
665          * It is OK, because this socket enters to hash table only
666          * after validation is complete.
667          */
668         sk->sk_state = TCP_LISTEN;
669         if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
670                 inet->inet_sport = htons(inet->inet_num);
671
672                 sk_dst_reset(sk);
673                 sk->sk_prot->hash(sk);
674
675                 return 0;
676         }
677
678         sk->sk_state = TCP_CLOSE;
679         __reqsk_queue_destroy(&icsk->icsk_accept_queue);
680         return -EADDRINUSE;
681 }
682 EXPORT_SYMBOL_GPL(inet_csk_listen_start);
683
684 /*
685  *      This routine closes sockets which have been at least partially
686  *      opened, but not yet accepted.
687  */
688 void inet_csk_listen_stop(struct sock *sk)
689 {
690         struct inet_connection_sock *icsk = inet_csk(sk);
691         struct request_sock *acc_req;
692         struct request_sock *req;
693
694         inet_csk_delete_keepalive_timer(sk);
695
696         /* make all the listen_opt local to us */
697         acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue);
698
699         /* Following specs, it would be better either to send FIN
700          * (and enter FIN-WAIT-1, it is normal close)
701          * or to send active reset (abort).
702          * Certainly, it is pretty dangerous while synflood, but it is
703          * bad justification for our negligence 8)
704          * To be honest, we are not able to make either
705          * of the variants now.                 --ANK
706          */
707         reqsk_queue_destroy(&icsk->icsk_accept_queue);
708
709         while ((req = acc_req) != NULL) {
710                 struct sock *child = req->sk;
711
712                 acc_req = req->dl_next;
713
714                 local_bh_disable();
715                 bh_lock_sock(child);
716                 WARN_ON(sock_owned_by_user(child));
717                 sock_hold(child);
718
719                 sk->sk_prot->disconnect(child, O_NONBLOCK);
720
721                 sock_orphan(child);
722
723                 percpu_counter_inc(sk->sk_prot->orphan_count);
724
725                 inet_csk_destroy_sock(child);
726
727                 bh_unlock_sock(child);
728                 local_bh_enable();
729                 sock_put(child);
730
731                 sk_acceptq_removed(sk);
732                 __reqsk_free(req);
733         }
734         WARN_ON(sk->sk_ack_backlog);
735 }
736 EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
737
738 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
739 {
740         struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
741         const struct inet_sock *inet = inet_sk(sk);
742
743         sin->sin_family         = AF_INET;
744         sin->sin_addr.s_addr    = inet->inet_daddr;
745         sin->sin_port           = inet->inet_dport;
746 }
747 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
748
749 #ifdef CONFIG_COMPAT
750 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
751                                char __user *optval, int __user *optlen)
752 {
753         const struct inet_connection_sock *icsk = inet_csk(sk);
754
755         if (icsk->icsk_af_ops->compat_getsockopt != NULL)
756                 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
757                                                             optval, optlen);
758         return icsk->icsk_af_ops->getsockopt(sk, level, optname,
759                                              optval, optlen);
760 }
761 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
762
763 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
764                                char __user *optval, unsigned int optlen)
765 {
766         const struct inet_connection_sock *icsk = inet_csk(sk);
767
768         if (icsk->icsk_af_ops->compat_setsockopt != NULL)
769                 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
770                                                             optval, optlen);
771         return icsk->icsk_af_ops->setsockopt(sk, level, optname,
772                                              optval, optlen);
773 }
774 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
775 #endif