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3f421baa ACM |
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> | |
a019d6fe | 26 | #include <net/xfrm.h> |
3f421baa ACM |
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 | static inline int inet_csk_bind_conflict(struct sock *sk, struct inet_bind_bucket *tb) | |
41 | { | |
42 | const u32 sk_rcv_saddr = inet_rcv_saddr(sk); | |
43 | struct sock *sk2; | |
44 | struct hlist_node *node; | |
45 | int reuse = sk->sk_reuse; | |
46 | ||
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 u32 sk2_rcv_saddr = inet_rcv_saddr(sk2); | |
56 | if (!sk2_rcv_saddr || !sk_rcv_saddr || | |
57 | sk2_rcv_saddr == sk_rcv_saddr) | |
58 | break; | |
59 | } | |
60 | } | |
61 | } | |
62 | return node != NULL; | |
63 | } | |
64 | ||
65 | /* Obtain a reference to a local port for the given sock, | |
66 | * if snum is zero it means select any available local port. | |
67 | */ | |
68 | int inet_csk_get_port(struct inet_hashinfo *hashinfo, | |
69 | struct sock *sk, unsigned short snum) | |
70 | { | |
71 | struct inet_bind_hashbucket *head; | |
72 | struct hlist_node *node; | |
73 | struct inet_bind_bucket *tb; | |
74 | int ret; | |
75 | ||
76 | local_bh_disable(); | |
77 | if (!snum) { | |
78 | int low = sysctl_local_port_range[0]; | |
79 | int high = sysctl_local_port_range[1]; | |
80 | int remaining = (high - low) + 1; | |
81 | int rover; | |
82 | ||
83 | spin_lock(&hashinfo->portalloc_lock); | |
84 | if (hashinfo->port_rover < low) | |
85 | rover = low; | |
86 | else | |
87 | rover = hashinfo->port_rover; | |
88 | do { | |
89 | rover++; | |
90 | if (rover > high) | |
91 | rover = low; | |
92 | head = &hashinfo->bhash[inet_bhashfn(rover, hashinfo->bhash_size)]; | |
93 | spin_lock(&head->lock); | |
94 | inet_bind_bucket_for_each(tb, node, &head->chain) | |
95 | if (tb->port == rover) | |
96 | goto next; | |
97 | break; | |
98 | next: | |
99 | spin_unlock(&head->lock); | |
100 | } while (--remaining > 0); | |
101 | hashinfo->port_rover = rover; | |
102 | spin_unlock(&hashinfo->portalloc_lock); | |
103 | ||
104 | /* Exhausted local port range during search? It is not | |
105 | * possible for us to be holding one of the bind hash | |
106 | * locks if this test triggers, because if 'remaining' | |
107 | * drops to zero, we broke out of the do/while loop at | |
108 | * the top level, not from the 'break;' statement. | |
109 | */ | |
110 | ret = 1; | |
111 | if (remaining <= 0) | |
112 | goto fail; | |
113 | ||
114 | /* OK, here is the one we will use. HEAD is | |
115 | * non-NULL and we hold it's mutex. | |
116 | */ | |
117 | snum = rover; | |
118 | } else { | |
119 | head = &hashinfo->bhash[inet_bhashfn(snum, hashinfo->bhash_size)]; | |
120 | spin_lock(&head->lock); | |
121 | inet_bind_bucket_for_each(tb, node, &head->chain) | |
122 | if (tb->port == snum) | |
123 | goto tb_found; | |
124 | } | |
125 | tb = NULL; | |
126 | goto tb_not_found; | |
127 | tb_found: | |
128 | if (!hlist_empty(&tb->owners)) { | |
129 | if (sk->sk_reuse > 1) | |
130 | goto success; | |
131 | if (tb->fastreuse > 0 && | |
132 | sk->sk_reuse && sk->sk_state != TCP_LISTEN) { | |
133 | goto success; | |
134 | } else { | |
135 | ret = 1; | |
136 | if (inet_csk_bind_conflict(sk, tb)) | |
137 | goto fail_unlock; | |
138 | } | |
139 | } | |
140 | tb_not_found: | |
141 | ret = 1; | |
142 | if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep, head, snum)) == NULL) | |
143 | goto fail_unlock; | |
144 | if (hlist_empty(&tb->owners)) { | |
145 | if (sk->sk_reuse && sk->sk_state != TCP_LISTEN) | |
146 | tb->fastreuse = 1; | |
147 | else | |
148 | tb->fastreuse = 0; | |
149 | } else if (tb->fastreuse && | |
150 | (!sk->sk_reuse || sk->sk_state == TCP_LISTEN)) | |
151 | tb->fastreuse = 0; | |
152 | success: | |
153 | if (!inet_csk(sk)->icsk_bind_hash) | |
154 | inet_bind_hash(sk, tb, snum); | |
155 | BUG_TRAP(inet_csk(sk)->icsk_bind_hash == tb); | |
156 | ret = 0; | |
157 | ||
158 | fail_unlock: | |
159 | spin_unlock(&head->lock); | |
160 | fail: | |
161 | local_bh_enable(); | |
162 | return ret; | |
163 | } | |
164 | ||
165 | EXPORT_SYMBOL_GPL(inet_csk_get_port); | |
166 | ||
167 | /* | |
168 | * Wait for an incoming connection, avoid race conditions. This must be called | |
169 | * with the socket locked. | |
170 | */ | |
171 | static int inet_csk_wait_for_connect(struct sock *sk, long timeo) | |
172 | { | |
173 | struct inet_connection_sock *icsk = inet_csk(sk); | |
174 | DEFINE_WAIT(wait); | |
175 | int err; | |
176 | ||
177 | /* | |
178 | * True wake-one mechanism for incoming connections: only | |
179 | * one process gets woken up, not the 'whole herd'. | |
180 | * Since we do not 'race & poll' for established sockets | |
181 | * anymore, the common case will execute the loop only once. | |
182 | * | |
183 | * Subtle issue: "add_wait_queue_exclusive()" will be added | |
184 | * after any current non-exclusive waiters, and we know that | |
185 | * it will always _stay_ after any new non-exclusive waiters | |
186 | * because all non-exclusive waiters are added at the | |
187 | * beginning of the wait-queue. As such, it's ok to "drop" | |
188 | * our exclusiveness temporarily when we get woken up without | |
189 | * having to remove and re-insert us on the wait queue. | |
190 | */ | |
191 | for (;;) { | |
192 | prepare_to_wait_exclusive(sk->sk_sleep, &wait, | |
193 | TASK_INTERRUPTIBLE); | |
194 | release_sock(sk); | |
195 | if (reqsk_queue_empty(&icsk->icsk_accept_queue)) | |
196 | timeo = schedule_timeout(timeo); | |
197 | lock_sock(sk); | |
198 | err = 0; | |
199 | if (!reqsk_queue_empty(&icsk->icsk_accept_queue)) | |
200 | break; | |
201 | err = -EINVAL; | |
202 | if (sk->sk_state != TCP_LISTEN) | |
203 | break; | |
204 | err = sock_intr_errno(timeo); | |
205 | if (signal_pending(current)) | |
206 | break; | |
207 | err = -EAGAIN; | |
208 | if (!timeo) | |
209 | break; | |
210 | } | |
211 | finish_wait(sk->sk_sleep, &wait); | |
212 | return err; | |
213 | } | |
214 | ||
215 | /* | |
216 | * This will accept the next outstanding connection. | |
217 | */ | |
218 | struct sock *inet_csk_accept(struct sock *sk, int flags, int *err) | |
219 | { | |
220 | struct inet_connection_sock *icsk = inet_csk(sk); | |
221 | struct sock *newsk; | |
222 | int error; | |
223 | ||
224 | lock_sock(sk); | |
225 | ||
226 | /* We need to make sure that this socket is listening, | |
227 | * and that it has something pending. | |
228 | */ | |
229 | error = -EINVAL; | |
230 | if (sk->sk_state != TCP_LISTEN) | |
231 | goto out_err; | |
232 | ||
233 | /* Find already established connection */ | |
234 | if (reqsk_queue_empty(&icsk->icsk_accept_queue)) { | |
235 | long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK); | |
236 | ||
237 | /* If this is a non blocking socket don't sleep */ | |
238 | error = -EAGAIN; | |
239 | if (!timeo) | |
240 | goto out_err; | |
241 | ||
242 | error = inet_csk_wait_for_connect(sk, timeo); | |
243 | if (error) | |
244 | goto out_err; | |
245 | } | |
246 | ||
247 | newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk); | |
248 | BUG_TRAP(newsk->sk_state != TCP_SYN_RECV); | |
249 | out: | |
250 | release_sock(sk); | |
251 | return newsk; | |
252 | out_err: | |
253 | newsk = NULL; | |
254 | *err = error; | |
255 | goto out; | |
256 | } | |
257 | ||
258 | EXPORT_SYMBOL(inet_csk_accept); | |
259 | ||
260 | /* | |
261 | * Using different timers for retransmit, delayed acks and probes | |
262 | * We may wish use just one timer maintaining a list of expire jiffies | |
263 | * to optimize. | |
264 | */ | |
265 | void inet_csk_init_xmit_timers(struct sock *sk, | |
266 | void (*retransmit_handler)(unsigned long), | |
267 | void (*delack_handler)(unsigned long), | |
268 | void (*keepalive_handler)(unsigned long)) | |
269 | { | |
270 | struct inet_connection_sock *icsk = inet_csk(sk); | |
271 | ||
272 | init_timer(&icsk->icsk_retransmit_timer); | |
273 | init_timer(&icsk->icsk_delack_timer); | |
274 | init_timer(&sk->sk_timer); | |
275 | ||
276 | icsk->icsk_retransmit_timer.function = retransmit_handler; | |
277 | icsk->icsk_delack_timer.function = delack_handler; | |
278 | sk->sk_timer.function = keepalive_handler; | |
279 | ||
280 | icsk->icsk_retransmit_timer.data = | |
281 | icsk->icsk_delack_timer.data = | |
282 | sk->sk_timer.data = (unsigned long)sk; | |
283 | ||
284 | icsk->icsk_pending = icsk->icsk_ack.pending = 0; | |
285 | } | |
286 | ||
287 | EXPORT_SYMBOL(inet_csk_init_xmit_timers); | |
288 | ||
289 | void inet_csk_clear_xmit_timers(struct sock *sk) | |
290 | { | |
291 | struct inet_connection_sock *icsk = inet_csk(sk); | |
292 | ||
293 | icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0; | |
294 | ||
295 | sk_stop_timer(sk, &icsk->icsk_retransmit_timer); | |
296 | sk_stop_timer(sk, &icsk->icsk_delack_timer); | |
297 | sk_stop_timer(sk, &sk->sk_timer); | |
298 | } | |
299 | ||
300 | EXPORT_SYMBOL(inet_csk_clear_xmit_timers); | |
301 | ||
302 | void inet_csk_delete_keepalive_timer(struct sock *sk) | |
303 | { | |
304 | sk_stop_timer(sk, &sk->sk_timer); | |
305 | } | |
306 | ||
307 | EXPORT_SYMBOL(inet_csk_delete_keepalive_timer); | |
308 | ||
309 | void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len) | |
310 | { | |
311 | sk_reset_timer(sk, &sk->sk_timer, jiffies + len); | |
312 | } | |
313 | ||
314 | EXPORT_SYMBOL(inet_csk_reset_keepalive_timer); | |
315 | ||
316 | struct dst_entry* inet_csk_route_req(struct sock *sk, | |
317 | const struct request_sock *req) | |
318 | { | |
319 | struct rtable *rt; | |
320 | const struct inet_request_sock *ireq = inet_rsk(req); | |
321 | struct ip_options *opt = inet_rsk(req)->opt; | |
322 | struct flowi fl = { .oif = sk->sk_bound_dev_if, | |
323 | .nl_u = { .ip4_u = | |
324 | { .daddr = ((opt && opt->srr) ? | |
325 | opt->faddr : | |
326 | ireq->rmt_addr), | |
327 | .saddr = ireq->loc_addr, | |
328 | .tos = RT_CONN_FLAGS(sk) } }, | |
329 | .proto = sk->sk_protocol, | |
330 | .uli_u = { .ports = | |
331 | { .sport = inet_sk(sk)->sport, | |
332 | .dport = ireq->rmt_port } } }; | |
333 | ||
334 | if (ip_route_output_flow(&rt, &fl, sk, 0)) { | |
335 | IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES); | |
336 | return NULL; | |
337 | } | |
338 | if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) { | |
339 | ip_rt_put(rt); | |
340 | IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES); | |
341 | return NULL; | |
342 | } | |
343 | return &rt->u.dst; | |
344 | } | |
345 | ||
346 | EXPORT_SYMBOL_GPL(inet_csk_route_req); | |
347 | ||
348 | static inline u32 inet_synq_hash(const u32 raddr, const u16 rport, | |
349 | const u32 rnd, const u16 synq_hsize) | |
350 | { | |
351 | return jhash_2words(raddr, (u32)rport, rnd) & (synq_hsize - 1); | |
352 | } | |
353 | ||
354 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) | |
355 | #define AF_INET_FAMILY(fam) ((fam) == AF_INET) | |
356 | #else | |
357 | #define AF_INET_FAMILY(fam) 1 | |
358 | #endif | |
359 | ||
360 | struct request_sock *inet_csk_search_req(const struct sock *sk, | |
361 | struct request_sock ***prevp, | |
362 | const __u16 rport, const __u32 raddr, | |
363 | const __u32 laddr) | |
364 | { | |
365 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
366 | struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt; | |
367 | struct request_sock *req, **prev; | |
368 | ||
369 | for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd, | |
370 | lopt->nr_table_entries)]; | |
371 | (req = *prev) != NULL; | |
372 | prev = &req->dl_next) { | |
373 | const struct inet_request_sock *ireq = inet_rsk(req); | |
374 | ||
375 | if (ireq->rmt_port == rport && | |
376 | ireq->rmt_addr == raddr && | |
377 | ireq->loc_addr == laddr && | |
378 | AF_INET_FAMILY(req->rsk_ops->family)) { | |
379 | BUG_TRAP(!req->sk); | |
380 | *prevp = prev; | |
381 | break; | |
382 | } | |
383 | } | |
384 | ||
385 | return req; | |
386 | } | |
387 | ||
388 | EXPORT_SYMBOL_GPL(inet_csk_search_req); | |
389 | ||
390 | void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, | |
391 | const unsigned timeout) | |
392 | { | |
393 | struct inet_connection_sock *icsk = inet_csk(sk); | |
394 | struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt; | |
395 | const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port, | |
396 | lopt->hash_rnd, lopt->nr_table_entries); | |
397 | ||
398 | reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout); | |
399 | inet_csk_reqsk_queue_added(sk, timeout); | |
400 | } | |
401 | ||
a019d6fe ACM |
402 | /* Only thing we need from tcp.h */ |
403 | extern int sysctl_tcp_synack_retries; | |
404 | ||
3f421baa | 405 | EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); |
9f1d2604 | 406 | |
a019d6fe ACM |
407 | void inet_csk_reqsk_queue_prune(struct sock *parent, |
408 | const unsigned long interval, | |
409 | const unsigned long timeout, | |
410 | const unsigned long max_rto) | |
411 | { | |
412 | struct inet_connection_sock *icsk = inet_csk(parent); | |
413 | struct request_sock_queue *queue = &icsk->icsk_accept_queue; | |
414 | struct listen_sock *lopt = queue->listen_opt; | |
415 | int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries; | |
416 | int thresh = max_retries; | |
417 | unsigned long now = jiffies; | |
418 | struct request_sock **reqp, *req; | |
419 | int i, budget; | |
420 | ||
421 | if (lopt == NULL || lopt->qlen == 0) | |
422 | return; | |
423 | ||
424 | /* Normally all the openreqs are young and become mature | |
425 | * (i.e. converted to established socket) for first timeout. | |
426 | * If synack was not acknowledged for 3 seconds, it means | |
427 | * one of the following things: synack was lost, ack was lost, | |
428 | * rtt is high or nobody planned to ack (i.e. synflood). | |
429 | * When server is a bit loaded, queue is populated with old | |
430 | * open requests, reducing effective size of queue. | |
431 | * When server is well loaded, queue size reduces to zero | |
432 | * after several minutes of work. It is not synflood, | |
433 | * it is normal operation. The solution is pruning | |
434 | * too old entries overriding normal timeout, when | |
435 | * situation becomes dangerous. | |
436 | * | |
437 | * Essentially, we reserve half of room for young | |
438 | * embrions; and abort old ones without pity, if old | |
439 | * ones are about to clog our table. | |
440 | */ | |
441 | if (lopt->qlen>>(lopt->max_qlen_log-1)) { | |
442 | int young = (lopt->qlen_young<<1); | |
443 | ||
444 | while (thresh > 2) { | |
445 | if (lopt->qlen < young) | |
446 | break; | |
447 | thresh--; | |
448 | young <<= 1; | |
449 | } | |
450 | } | |
451 | ||
452 | if (queue->rskq_defer_accept) | |
453 | max_retries = queue->rskq_defer_accept; | |
454 | ||
455 | budget = 2 * (lopt->nr_table_entries / (timeout / interval)); | |
456 | i = lopt->clock_hand; | |
457 | ||
458 | do { | |
459 | reqp=&lopt->syn_table[i]; | |
460 | while ((req = *reqp) != NULL) { | |
461 | if (time_after_eq(now, req->expires)) { | |
462 | if ((req->retrans < thresh || | |
463 | (inet_rsk(req)->acked && req->retrans < max_retries)) | |
464 | && !req->rsk_ops->rtx_syn_ack(parent, req, NULL)) { | |
465 | unsigned long timeo; | |
466 | ||
467 | if (req->retrans++ == 0) | |
468 | lopt->qlen_young--; | |
469 | timeo = min((timeout << req->retrans), max_rto); | |
470 | req->expires = now + timeo; | |
471 | reqp = &req->dl_next; | |
472 | continue; | |
473 | } | |
474 | ||
475 | /* Drop this request */ | |
476 | inet_csk_reqsk_queue_unlink(parent, req, reqp); | |
477 | reqsk_queue_removed(queue, req); | |
478 | reqsk_free(req); | |
479 | continue; | |
480 | } | |
481 | reqp = &req->dl_next; | |
482 | } | |
483 | ||
484 | i = (i + 1) & (lopt->nr_table_entries - 1); | |
485 | ||
486 | } while (--budget > 0); | |
487 | ||
488 | lopt->clock_hand = i; | |
489 | ||
490 | if (lopt->qlen) | |
491 | inet_csk_reset_keepalive_timer(parent, interval); | |
492 | } | |
493 | ||
494 | EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune); | |
495 | ||
9f1d2604 ACM |
496 | struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req, |
497 | const unsigned int __nocast priority) | |
498 | { | |
499 | struct sock *newsk = sk_clone(sk, priority); | |
500 | ||
501 | if (newsk != NULL) { | |
502 | struct inet_connection_sock *newicsk = inet_csk(newsk); | |
503 | ||
504 | newsk->sk_state = TCP_SYN_RECV; | |
505 | newicsk->icsk_bind_hash = NULL; | |
506 | ||
507 | inet_sk(newsk)->dport = inet_rsk(req)->rmt_port; | |
508 | newsk->sk_write_space = sk_stream_write_space; | |
509 | ||
510 | newicsk->icsk_retransmits = 0; | |
6687e988 ACM |
511 | newicsk->icsk_backoff = 0; |
512 | newicsk->icsk_probes_out = 0; | |
9f1d2604 ACM |
513 | |
514 | /* Deinitialize accept_queue to trap illegal accesses. */ | |
515 | memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue)); | |
516 | } | |
517 | return newsk; | |
518 | } | |
519 | ||
520 | EXPORT_SYMBOL_GPL(inet_csk_clone); | |
a019d6fe ACM |
521 | |
522 | /* | |
523 | * At this point, there should be no process reference to this | |
524 | * socket, and thus no user references at all. Therefore we | |
525 | * can assume the socket waitqueue is inactive and nobody will | |
526 | * try to jump onto it. | |
527 | */ | |
528 | void inet_csk_destroy_sock(struct sock *sk) | |
529 | { | |
530 | BUG_TRAP(sk->sk_state == TCP_CLOSE); | |
531 | BUG_TRAP(sock_flag(sk, SOCK_DEAD)); | |
532 | ||
533 | /* It cannot be in hash table! */ | |
534 | BUG_TRAP(sk_unhashed(sk)); | |
535 | ||
536 | /* If it has not 0 inet_sk(sk)->num, it must be bound */ | |
537 | BUG_TRAP(!inet_sk(sk)->num || inet_csk(sk)->icsk_bind_hash); | |
538 | ||
539 | sk->sk_prot->destroy(sk); | |
540 | ||
541 | sk_stream_kill_queues(sk); | |
542 | ||
543 | xfrm_sk_free_policy(sk); | |
544 | ||
545 | sk_refcnt_debug_release(sk); | |
546 | ||
547 | atomic_dec(sk->sk_prot->orphan_count); | |
548 | sock_put(sk); | |
549 | } | |
550 | ||
551 | EXPORT_SYMBOL(inet_csk_destroy_sock); | |
552 | ||
553 | int inet_csk_listen_start(struct sock *sk, const int nr_table_entries) | |
554 | { | |
555 | struct inet_sock *inet = inet_sk(sk); | |
556 | struct inet_connection_sock *icsk = inet_csk(sk); | |
557 | int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries); | |
558 | ||
559 | if (rc != 0) | |
560 | return rc; | |
561 | ||
562 | sk->sk_max_ack_backlog = 0; | |
563 | sk->sk_ack_backlog = 0; | |
564 | inet_csk_delack_init(sk); | |
565 | ||
566 | /* There is race window here: we announce ourselves listening, | |
567 | * but this transition is still not validated by get_port(). | |
568 | * It is OK, because this socket enters to hash table only | |
569 | * after validation is complete. | |
570 | */ | |
571 | sk->sk_state = TCP_LISTEN; | |
572 | if (!sk->sk_prot->get_port(sk, inet->num)) { | |
573 | inet->sport = htons(inet->num); | |
574 | ||
575 | sk_dst_reset(sk); | |
576 | sk->sk_prot->hash(sk); | |
577 | ||
578 | return 0; | |
579 | } | |
580 | ||
581 | sk->sk_state = TCP_CLOSE; | |
582 | __reqsk_queue_destroy(&icsk->icsk_accept_queue); | |
583 | return -EADDRINUSE; | |
584 | } | |
585 | ||
586 | EXPORT_SYMBOL_GPL(inet_csk_listen_start); | |
587 | ||
588 | /* | |
589 | * This routine closes sockets which have been at least partially | |
590 | * opened, but not yet accepted. | |
591 | */ | |
592 | void inet_csk_listen_stop(struct sock *sk) | |
593 | { | |
594 | struct inet_connection_sock *icsk = inet_csk(sk); | |
595 | struct request_sock *acc_req; | |
596 | struct request_sock *req; | |
597 | ||
598 | inet_csk_delete_keepalive_timer(sk); | |
599 | ||
600 | /* make all the listen_opt local to us */ | |
601 | acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue); | |
602 | ||
603 | /* Following specs, it would be better either to send FIN | |
604 | * (and enter FIN-WAIT-1, it is normal close) | |
605 | * or to send active reset (abort). | |
606 | * Certainly, it is pretty dangerous while synflood, but it is | |
607 | * bad justification for our negligence 8) | |
608 | * To be honest, we are not able to make either | |
609 | * of the variants now. --ANK | |
610 | */ | |
611 | reqsk_queue_destroy(&icsk->icsk_accept_queue); | |
612 | ||
613 | while ((req = acc_req) != NULL) { | |
614 | struct sock *child = req->sk; | |
615 | ||
616 | acc_req = req->dl_next; | |
617 | ||
618 | local_bh_disable(); | |
619 | bh_lock_sock(child); | |
620 | BUG_TRAP(!sock_owned_by_user(child)); | |
621 | sock_hold(child); | |
622 | ||
623 | sk->sk_prot->disconnect(child, O_NONBLOCK); | |
624 | ||
625 | sock_orphan(child); | |
626 | ||
627 | atomic_inc(sk->sk_prot->orphan_count); | |
628 | ||
629 | inet_csk_destroy_sock(child); | |
630 | ||
631 | bh_unlock_sock(child); | |
632 | local_bh_enable(); | |
633 | sock_put(child); | |
634 | ||
635 | sk_acceptq_removed(sk); | |
636 | __reqsk_free(req); | |
637 | } | |
638 | BUG_TRAP(!sk->sk_ack_backlog); | |
639 | } | |
640 | ||
641 | EXPORT_SYMBOL_GPL(inet_csk_listen_stop); |