net/ipv4: EXPORT_SYMBOL cleanups
[linux-3.10.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,
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         const __be32 sk_rcv_saddr = inet_rcv_saddr(sk);
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 = inet_rcv_saddr(sk2);
79                                 if (!sk2_rcv_saddr || !sk_rcv_saddr ||
80                                     sk2_rcv_saddr == sk_rcv_saddr)
81                                         break;
82                         }
83                 }
84         }
85         return node != NULL;
86 }
87 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
88
89 /* Obtain a reference to a local port for the given sock,
90  * if snum is zero it means select any available local port.
91  */
92 int inet_csk_get_port(struct sock *sk, unsigned short snum)
93 {
94         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
95         struct inet_bind_hashbucket *head;
96         struct hlist_node *node;
97         struct inet_bind_bucket *tb;
98         int ret, attempts = 5;
99         struct net *net = sock_net(sk);
100         int smallest_size = -1, smallest_rover;
101
102         local_bh_disable();
103         if (!snum) {
104                 int remaining, rover, low, high;
105
106 again:
107                 inet_get_local_port_range(&low, &high);
108                 remaining = (high - low) + 1;
109                 smallest_rover = rover = net_random() % remaining + low;
110
111                 smallest_size = -1;
112                 do {
113                         if (inet_is_reserved_local_port(rover))
114                                 goto next_nolock;
115                         head = &hashinfo->bhash[inet_bhashfn(net, rover,
116                                         hashinfo->bhash_size)];
117                         spin_lock(&head->lock);
118                         inet_bind_bucket_for_each(tb, node, &head->chain)
119                                 if (net_eq(ib_net(tb), net) && tb->port == rover) {
120                                         if (tb->fastreuse > 0 &&
121                                             sk->sk_reuse &&
122                                             sk->sk_state != TCP_LISTEN &&
123                                             (tb->num_owners < smallest_size || smallest_size == -1)) {
124                                                 smallest_size = tb->num_owners;
125                                                 smallest_rover = rover;
126                                                 if (atomic_read(&hashinfo->bsockets) > (high - low) + 1) {
127                                                         spin_unlock(&head->lock);
128                                                         snum = smallest_rover;
129                                                         goto have_snum;
130                                                 }
131                                         }
132                                         goto next;
133                                 }
134                         break;
135                 next:
136                         spin_unlock(&head->lock);
137                 next_nolock:
138                         if (++rover > high)
139                                 rover = low;
140                 } while (--remaining > 0);
141
142                 /* Exhausted local port range during search?  It is not
143                  * possible for us to be holding one of the bind hash
144                  * locks if this test triggers, because if 'remaining'
145                  * drops to zero, we broke out of the do/while loop at
146                  * the top level, not from the 'break;' statement.
147                  */
148                 ret = 1;
149                 if (remaining <= 0) {
150                         if (smallest_size != -1) {
151                                 snum = smallest_rover;
152                                 goto have_snum;
153                         }
154                         goto fail;
155                 }
156                 /* OK, here is the one we will use.  HEAD is
157                  * non-NULL and we hold it's mutex.
158                  */
159                 snum = rover;
160         } else {
161 have_snum:
162                 head = &hashinfo->bhash[inet_bhashfn(net, snum,
163                                 hashinfo->bhash_size)];
164                 spin_lock(&head->lock);
165                 inet_bind_bucket_for_each(tb, node, &head->chain)
166                         if (net_eq(ib_net(tb), net) && tb->port == snum)
167                                 goto tb_found;
168         }
169         tb = NULL;
170         goto tb_not_found;
171 tb_found:
172         if (!hlist_empty(&tb->owners)) {
173                 if (tb->fastreuse > 0 &&
174                     sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
175                     smallest_size == -1) {
176                         goto success;
177                 } else {
178                         ret = 1;
179                         if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb)) {
180                                 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
181                                     smallest_size != -1 && --attempts >= 0) {
182                                         spin_unlock(&head->lock);
183                                         goto again;
184                                 }
185                                 goto fail_unlock;
186                         }
187                 }
188         }
189 tb_not_found:
190         ret = 1;
191         if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
192                                         net, head, snum)) == NULL)
193                 goto fail_unlock;
194         if (hlist_empty(&tb->owners)) {
195                 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
196                         tb->fastreuse = 1;
197                 else
198                         tb->fastreuse = 0;
199         } else if (tb->fastreuse &&
200                    (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
201                 tb->fastreuse = 0;
202 success:
203         if (!inet_csk(sk)->icsk_bind_hash)
204                 inet_bind_hash(sk, tb, snum);
205         WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
206         ret = 0;
207
208 fail_unlock:
209         spin_unlock(&head->lock);
210 fail:
211         local_bh_enable();
212         return ret;
213 }
214 EXPORT_SYMBOL_GPL(inet_csk_get_port);
215
216 /*
217  * Wait for an incoming connection, avoid race conditions. This must be called
218  * with the socket locked.
219  */
220 static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
221 {
222         struct inet_connection_sock *icsk = inet_csk(sk);
223         DEFINE_WAIT(wait);
224         int err;
225
226         /*
227          * True wake-one mechanism for incoming connections: only
228          * one process gets woken up, not the 'whole herd'.
229          * Since we do not 'race & poll' for established sockets
230          * anymore, the common case will execute the loop only once.
231          *
232          * Subtle issue: "add_wait_queue_exclusive()" will be added
233          * after any current non-exclusive waiters, and we know that
234          * it will always _stay_ after any new non-exclusive waiters
235          * because all non-exclusive waiters are added at the
236          * beginning of the wait-queue. As such, it's ok to "drop"
237          * our exclusiveness temporarily when we get woken up without
238          * having to remove and re-insert us on the wait queue.
239          */
240         for (;;) {
241                 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
242                                           TASK_INTERRUPTIBLE);
243                 release_sock(sk);
244                 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
245                         timeo = schedule_timeout(timeo);
246                 lock_sock(sk);
247                 err = 0;
248                 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
249                         break;
250                 err = -EINVAL;
251                 if (sk->sk_state != TCP_LISTEN)
252                         break;
253                 err = sock_intr_errno(timeo);
254                 if (signal_pending(current))
255                         break;
256                 err = -EAGAIN;
257                 if (!timeo)
258                         break;
259         }
260         finish_wait(sk_sleep(sk), &wait);
261         return err;
262 }
263
264 /*
265  * This will accept the next outstanding connection.
266  */
267 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
268 {
269         struct inet_connection_sock *icsk = inet_csk(sk);
270         struct sock *newsk;
271         int error;
272
273         lock_sock(sk);
274
275         /* We need to make sure that this socket is listening,
276          * and that it has something pending.
277          */
278         error = -EINVAL;
279         if (sk->sk_state != TCP_LISTEN)
280                 goto out_err;
281
282         /* Find already established connection */
283         if (reqsk_queue_empty(&icsk->icsk_accept_queue)) {
284                 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
285
286                 /* If this is a non blocking socket don't sleep */
287                 error = -EAGAIN;
288                 if (!timeo)
289                         goto out_err;
290
291                 error = inet_csk_wait_for_connect(sk, timeo);
292                 if (error)
293                         goto out_err;
294         }
295
296         newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
297         WARN_ON(newsk->sk_state == TCP_SYN_RECV);
298 out:
299         release_sock(sk);
300         return newsk;
301 out_err:
302         newsk = NULL;
303         *err = error;
304         goto out;
305 }
306 EXPORT_SYMBOL(inet_csk_accept);
307
308 /*
309  * Using different timers for retransmit, delayed acks and probes
310  * We may wish use just one timer maintaining a list of expire jiffies
311  * to optimize.
312  */
313 void inet_csk_init_xmit_timers(struct sock *sk,
314                                void (*retransmit_handler)(unsigned long),
315                                void (*delack_handler)(unsigned long),
316                                void (*keepalive_handler)(unsigned long))
317 {
318         struct inet_connection_sock *icsk = inet_csk(sk);
319
320         setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
321                         (unsigned long)sk);
322         setup_timer(&icsk->icsk_delack_timer, delack_handler,
323                         (unsigned long)sk);
324         setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
325         icsk->icsk_pending = icsk->icsk_ack.pending = 0;
326 }
327 EXPORT_SYMBOL(inet_csk_init_xmit_timers);
328
329 void inet_csk_clear_xmit_timers(struct sock *sk)
330 {
331         struct inet_connection_sock *icsk = inet_csk(sk);
332
333         icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
334
335         sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
336         sk_stop_timer(sk, &icsk->icsk_delack_timer);
337         sk_stop_timer(sk, &sk->sk_timer);
338 }
339 EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
340
341 void inet_csk_delete_keepalive_timer(struct sock *sk)
342 {
343         sk_stop_timer(sk, &sk->sk_timer);
344 }
345 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
346
347 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
348 {
349         sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
350 }
351 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
352
353 struct dst_entry *inet_csk_route_req(struct sock *sk,
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 *opt = inet_rsk(req)->opt;
359         struct flowi fl = { .oif = sk->sk_bound_dev_if,
360                             .mark = sk->sk_mark,
361                             .nl_u = { .ip4_u =
362                                       { .daddr = ((opt && opt->srr) ?
363                                                   opt->faddr :
364                                                   ireq->rmt_addr),
365                                         .saddr = ireq->loc_addr,
366                                         .tos = RT_CONN_FLAGS(sk) } },
367                             .proto = sk->sk_protocol,
368                             .flags = inet_sk_flowi_flags(sk),
369                             .uli_u = { .ports =
370                                        { .sport = inet_sk(sk)->inet_sport,
371                                          .dport = ireq->rmt_port } } };
372         struct net *net = sock_net(sk);
373
374         security_req_classify_flow(req, &fl);
375         if (ip_route_output_flow(net, &rt, &fl, sk, 0))
376                 goto no_route;
377         if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
378                 goto route_err;
379         return &rt->dst;
380
381 route_err:
382         ip_rt_put(rt);
383 no_route:
384         IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
385         return NULL;
386 }
387 EXPORT_SYMBOL_GPL(inet_csk_route_req);
388
389 static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
390                                  const u32 rnd, const u32 synq_hsize)
391 {
392         return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
393 }
394
395 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
396 #define AF_INET_FAMILY(fam) ((fam) == AF_INET)
397 #else
398 #define AF_INET_FAMILY(fam) 1
399 #endif
400
401 struct request_sock *inet_csk_search_req(const struct sock *sk,
402                                          struct request_sock ***prevp,
403                                          const __be16 rport, const __be32 raddr,
404                                          const __be32 laddr)
405 {
406         const struct inet_connection_sock *icsk = inet_csk(sk);
407         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
408         struct request_sock *req, **prev;
409
410         for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd,
411                                                     lopt->nr_table_entries)];
412              (req = *prev) != NULL;
413              prev = &req->dl_next) {
414                 const struct inet_request_sock *ireq = inet_rsk(req);
415
416                 if (ireq->rmt_port == rport &&
417                     ireq->rmt_addr == raddr &&
418                     ireq->loc_addr == laddr &&
419                     AF_INET_FAMILY(req->rsk_ops->family)) {
420                         WARN_ON(req->sk);
421                         *prevp = prev;
422                         break;
423                 }
424         }
425
426         return req;
427 }
428 EXPORT_SYMBOL_GPL(inet_csk_search_req);
429
430 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
431                                    unsigned long timeout)
432 {
433         struct inet_connection_sock *icsk = inet_csk(sk);
434         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
435         const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port,
436                                      lopt->hash_rnd, lopt->nr_table_entries);
437
438         reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
439         inet_csk_reqsk_queue_added(sk, timeout);
440 }
441 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
442
443 /* Only thing we need from tcp.h */
444 extern int sysctl_tcp_synack_retries;
445
446
447 /* Decide when to expire the request and when to resend SYN-ACK */
448 static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
449                                   const int max_retries,
450                                   const u8 rskq_defer_accept,
451                                   int *expire, int *resend)
452 {
453         if (!rskq_defer_accept) {
454                 *expire = req->retrans >= thresh;
455                 *resend = 1;
456                 return;
457         }
458         *expire = req->retrans >= thresh &&
459                   (!inet_rsk(req)->acked || req->retrans >= max_retries);
460         /*
461          * Do not resend while waiting for data after ACK,
462          * start to resend on end of deferring period to give
463          * last chance for data or ACK to create established socket.
464          */
465         *resend = !inet_rsk(req)->acked ||
466                   req->retrans >= rskq_defer_accept - 1;
467 }
468
469 void inet_csk_reqsk_queue_prune(struct sock *parent,
470                                 const unsigned long interval,
471                                 const unsigned long timeout,
472                                 const unsigned long max_rto)
473 {
474         struct inet_connection_sock *icsk = inet_csk(parent);
475         struct request_sock_queue *queue = &icsk->icsk_accept_queue;
476         struct listen_sock *lopt = queue->listen_opt;
477         int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
478         int thresh = max_retries;
479         unsigned long now = jiffies;
480         struct request_sock **reqp, *req;
481         int i, budget;
482
483         if (lopt == NULL || lopt->qlen == 0)
484                 return;
485
486         /* Normally all the openreqs are young and become mature
487          * (i.e. converted to established socket) for first timeout.
488          * If synack was not acknowledged for 3 seconds, it means
489          * one of the following things: synack was lost, ack was lost,
490          * rtt is high or nobody planned to ack (i.e. synflood).
491          * When server is a bit loaded, queue is populated with old
492          * open requests, reducing effective size of queue.
493          * When server is well loaded, queue size reduces to zero
494          * after several minutes of work. It is not synflood,
495          * it is normal operation. The solution is pruning
496          * too old entries overriding normal timeout, when
497          * situation becomes dangerous.
498          *
499          * Essentially, we reserve half of room for young
500          * embrions; and abort old ones without pity, if old
501          * ones are about to clog our table.
502          */
503         if (lopt->qlen>>(lopt->max_qlen_log-1)) {
504                 int young = (lopt->qlen_young<<1);
505
506                 while (thresh > 2) {
507                         if (lopt->qlen < young)
508                                 break;
509                         thresh--;
510                         young <<= 1;
511                 }
512         }
513
514         if (queue->rskq_defer_accept)
515                 max_retries = queue->rskq_defer_accept;
516
517         budget = 2 * (lopt->nr_table_entries / (timeout / interval));
518         i = lopt->clock_hand;
519
520         do {
521                 reqp=&lopt->syn_table[i];
522                 while ((req = *reqp) != NULL) {
523                         if (time_after_eq(now, req->expires)) {
524                                 int expire = 0, resend = 0;
525
526                                 syn_ack_recalc(req, thresh, max_retries,
527                                                queue->rskq_defer_accept,
528                                                &expire, &resend);
529                                 if (req->rsk_ops->syn_ack_timeout)
530                                         req->rsk_ops->syn_ack_timeout(parent, req);
531                                 if (!expire &&
532                                     (!resend ||
533                                      !req->rsk_ops->rtx_syn_ack(parent, req, NULL) ||
534                                      inet_rsk(req)->acked)) {
535                                         unsigned long timeo;
536
537                                         if (req->retrans++ == 0)
538                                                 lopt->qlen_young--;
539                                         timeo = min((timeout << req->retrans), max_rto);
540                                         req->expires = now + timeo;
541                                         reqp = &req->dl_next;
542                                         continue;
543                                 }
544
545                                 /* Drop this request */
546                                 inet_csk_reqsk_queue_unlink(parent, req, reqp);
547                                 reqsk_queue_removed(queue, req);
548                                 reqsk_free(req);
549                                 continue;
550                         }
551                         reqp = &req->dl_next;
552                 }
553
554                 i = (i + 1) & (lopt->nr_table_entries - 1);
555
556         } while (--budget > 0);
557
558         lopt->clock_hand = i;
559
560         if (lopt->qlen)
561                 inet_csk_reset_keepalive_timer(parent, interval);
562 }
563 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
564
565 struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req,
566                             const gfp_t priority)
567 {
568         struct sock *newsk = sk_clone(sk, priority);
569
570         if (newsk != NULL) {
571                 struct inet_connection_sock *newicsk = inet_csk(newsk);
572
573                 newsk->sk_state = TCP_SYN_RECV;
574                 newicsk->icsk_bind_hash = NULL;
575
576                 inet_sk(newsk)->inet_dport = inet_rsk(req)->rmt_port;
577                 inet_sk(newsk)->inet_num = ntohs(inet_rsk(req)->loc_port);
578                 inet_sk(newsk)->inet_sport = inet_rsk(req)->loc_port;
579                 newsk->sk_write_space = sk_stream_write_space;
580
581                 newicsk->icsk_retransmits = 0;
582                 newicsk->icsk_backoff     = 0;
583                 newicsk->icsk_probes_out  = 0;
584
585                 /* Deinitialize accept_queue to trap illegal accesses. */
586                 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
587
588                 security_inet_csk_clone(newsk, req);
589         }
590         return newsk;
591 }
592 EXPORT_SYMBOL_GPL(inet_csk_clone);
593
594 /*
595  * At this point, there should be no process reference to this
596  * socket, and thus no user references at all.  Therefore we
597  * can assume the socket waitqueue is inactive and nobody will
598  * try to jump onto it.
599  */
600 void inet_csk_destroy_sock(struct sock *sk)
601 {
602         WARN_ON(sk->sk_state != TCP_CLOSE);
603         WARN_ON(!sock_flag(sk, SOCK_DEAD));
604
605         /* It cannot be in hash table! */
606         WARN_ON(!sk_unhashed(sk));
607
608         /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
609         WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
610
611         sk->sk_prot->destroy(sk);
612
613         sk_stream_kill_queues(sk);
614
615         xfrm_sk_free_policy(sk);
616
617         sk_refcnt_debug_release(sk);
618
619         percpu_counter_dec(sk->sk_prot->orphan_count);
620         sock_put(sk);
621 }
622 EXPORT_SYMBOL(inet_csk_destroy_sock);
623
624 int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
625 {
626         struct inet_sock *inet = inet_sk(sk);
627         struct inet_connection_sock *icsk = inet_csk(sk);
628         int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
629
630         if (rc != 0)
631                 return rc;
632
633         sk->sk_max_ack_backlog = 0;
634         sk->sk_ack_backlog = 0;
635         inet_csk_delack_init(sk);
636
637         /* There is race window here: we announce ourselves listening,
638          * but this transition is still not validated by get_port().
639          * It is OK, because this socket enters to hash table only
640          * after validation is complete.
641          */
642         sk->sk_state = TCP_LISTEN;
643         if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
644                 inet->inet_sport = htons(inet->inet_num);
645
646                 sk_dst_reset(sk);
647                 sk->sk_prot->hash(sk);
648
649                 return 0;
650         }
651
652         sk->sk_state = TCP_CLOSE;
653         __reqsk_queue_destroy(&icsk->icsk_accept_queue);
654         return -EADDRINUSE;
655 }
656 EXPORT_SYMBOL_GPL(inet_csk_listen_start);
657
658 /*
659  *      This routine closes sockets which have been at least partially
660  *      opened, but not yet accepted.
661  */
662 void inet_csk_listen_stop(struct sock *sk)
663 {
664         struct inet_connection_sock *icsk = inet_csk(sk);
665         struct request_sock *acc_req;
666         struct request_sock *req;
667
668         inet_csk_delete_keepalive_timer(sk);
669
670         /* make all the listen_opt local to us */
671         acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue);
672
673         /* Following specs, it would be better either to send FIN
674          * (and enter FIN-WAIT-1, it is normal close)
675          * or to send active reset (abort).
676          * Certainly, it is pretty dangerous while synflood, but it is
677          * bad justification for our negligence 8)
678          * To be honest, we are not able to make either
679          * of the variants now.                 --ANK
680          */
681         reqsk_queue_destroy(&icsk->icsk_accept_queue);
682
683         while ((req = acc_req) != NULL) {
684                 struct sock *child = req->sk;
685
686                 acc_req = req->dl_next;
687
688                 local_bh_disable();
689                 bh_lock_sock(child);
690                 WARN_ON(sock_owned_by_user(child));
691                 sock_hold(child);
692
693                 sk->sk_prot->disconnect(child, O_NONBLOCK);
694
695                 sock_orphan(child);
696
697                 percpu_counter_inc(sk->sk_prot->orphan_count);
698
699                 inet_csk_destroy_sock(child);
700
701                 bh_unlock_sock(child);
702                 local_bh_enable();
703                 sock_put(child);
704
705                 sk_acceptq_removed(sk);
706                 __reqsk_free(req);
707         }
708         WARN_ON(sk->sk_ack_backlog);
709 }
710 EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
711
712 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
713 {
714         struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
715         const struct inet_sock *inet = inet_sk(sk);
716
717         sin->sin_family         = AF_INET;
718         sin->sin_addr.s_addr    = inet->inet_daddr;
719         sin->sin_port           = inet->inet_dport;
720 }
721 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
722
723 #ifdef CONFIG_COMPAT
724 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
725                                char __user *optval, int __user *optlen)
726 {
727         const struct inet_connection_sock *icsk = inet_csk(sk);
728
729         if (icsk->icsk_af_ops->compat_getsockopt != NULL)
730                 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
731                                                             optval, optlen);
732         return icsk->icsk_af_ops->getsockopt(sk, level, optname,
733                                              optval, optlen);
734 }
735 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
736
737 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
738                                char __user *optval, unsigned int optlen)
739 {
740         const struct inet_connection_sock *icsk = inet_csk(sk);
741
742         if (icsk->icsk_af_ops->compat_setsockopt != NULL)
743                 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
744                                                             optval, optlen);
745         return icsk->icsk_af_ops->setsockopt(sk, level, optname,
746                                              optval, optlen);
747 }
748 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
749 #endif