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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#include <net/tcp.h>
27#include <net/sock_reuseport.h>
28#include <net/addrconf.h>
29
30#ifdef INET_CSK_DEBUG
31const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
32EXPORT_SYMBOL(inet_csk_timer_bug_msg);
33#endif
34
35#if IS_ENABLED(CONFIG_IPV6)
36/* match_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses if IPv6
37 * only, and any IPv4 addresses if not IPv6 only
38 * match_wildcard == false: addresses must be exactly the same, i.e.
39 * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
40 * and 0.0.0.0 equals to 0.0.0.0 only
41 */
42static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6,
43 const struct in6_addr *sk2_rcv_saddr6,
44 __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
45 bool sk1_ipv6only, bool sk2_ipv6only,
46 bool match_wildcard)
47{
48 int addr_type = ipv6_addr_type(sk1_rcv_saddr6);
49 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
50
51 /* if both are mapped, treat as IPv4 */
52 if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
53 if (!sk2_ipv6only) {
54 if (sk1_rcv_saddr == sk2_rcv_saddr)
55 return true;
56 if (!sk1_rcv_saddr || !sk2_rcv_saddr)
57 return match_wildcard;
58 }
59 return false;
60 }
61
62 if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
63 return true;
64
65 if (addr_type2 == IPV6_ADDR_ANY && match_wildcard &&
66 !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
67 return true;
68
69 if (addr_type == IPV6_ADDR_ANY && match_wildcard &&
70 !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
71 return true;
72
73 if (sk2_rcv_saddr6 &&
74 ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6))
75 return true;
76
77 return false;
78}
79#endif
80
81/* match_wildcard == true: 0.0.0.0 equals to any IPv4 addresses
82 * match_wildcard == false: addresses must be exactly the same, i.e.
83 * 0.0.0.0 only equals to 0.0.0.0
84 */
85static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
86 bool sk2_ipv6only, bool match_wildcard)
87{
88 if (!sk2_ipv6only) {
89 if (sk1_rcv_saddr == sk2_rcv_saddr)
90 return true;
91 if (!sk1_rcv_saddr || !sk2_rcv_saddr)
92 return match_wildcard;
93 }
94 return false;
95}
96
97bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
98 bool match_wildcard)
99{
100#if IS_ENABLED(CONFIG_IPV6)
101 if (sk->sk_family == AF_INET6)
102 return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr,
103 inet6_rcv_saddr(sk2),
104 sk->sk_rcv_saddr,
105 sk2->sk_rcv_saddr,
106 ipv6_only_sock(sk),
107 ipv6_only_sock(sk2),
108 match_wildcard);
109#endif
110 return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr,
111 ipv6_only_sock(sk2), match_wildcard);
112}
113EXPORT_SYMBOL(inet_rcv_saddr_equal);
114
115void inet_get_local_port_range(struct net *net, int *low, int *high)
116{
117 unsigned int seq;
118
119 do {
120 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
121
122 *low = net->ipv4.ip_local_ports.range[0];
123 *high = net->ipv4.ip_local_ports.range[1];
124 } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
125}
126EXPORT_SYMBOL(inet_get_local_port_range);
127
128static int inet_csk_bind_conflict(const struct sock *sk,
129 const struct inet_bind_bucket *tb,
130 bool relax, bool reuseport_ok)
131{
132 struct sock *sk2;
133 bool reuse = sk->sk_reuse;
134 bool reuseport = !!sk->sk_reuseport && reuseport_ok;
135 kuid_t uid = sock_i_uid((struct sock *)sk);
136
137 /*
138 * Unlike other sk lookup places we do not check
139 * for sk_net here, since _all_ the socks listed
140 * in tb->owners list belong to the same net - the
141 * one this bucket belongs to.
142 */
143
144 sk_for_each_bound(sk2, &tb->owners) {
145 if (sk != sk2 &&
146 (!sk->sk_bound_dev_if ||
147 !sk2->sk_bound_dev_if ||
148 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
149 if ((!reuse || !sk2->sk_reuse ||
150 sk2->sk_state == TCP_LISTEN) &&
151 (!reuseport || !sk2->sk_reuseport ||
152 rcu_access_pointer(sk->sk_reuseport_cb) ||
153 (sk2->sk_state != TCP_TIME_WAIT &&
154 !uid_eq(uid, sock_i_uid(sk2))))) {
155 if (inet_rcv_saddr_equal(sk, sk2, true))
156 break;
157 }
158 if (!relax && reuse && sk2->sk_reuse &&
159 sk2->sk_state != TCP_LISTEN) {
160 if (inet_rcv_saddr_equal(sk, sk2, true))
161 break;
162 }
163 }
164 }
165 return sk2 != NULL;
166}
167
168/*
169 * Find an open port number for the socket. Returns with the
170 * inet_bind_hashbucket lock held.
171 */
172static struct inet_bind_hashbucket *
173inet_csk_find_open_port(struct sock *sk, struct inet_bind_bucket **tb_ret, int *port_ret)
174{
175 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
176 int port = 0;
177 struct inet_bind_hashbucket *head;
178 struct net *net = sock_net(sk);
179 int i, low, high, attempt_half;
180 struct inet_bind_bucket *tb;
181 u32 remaining, offset;
182
183 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
184other_half_scan:
185 inet_get_local_port_range(net, &low, &high);
186 high++; /* [32768, 60999] -> [32768, 61000[ */
187 if (high - low < 4)
188 attempt_half = 0;
189 if (attempt_half) {
190 int half = low + (((high - low) >> 2) << 1);
191
192 if (attempt_half == 1)
193 high = half;
194 else
195 low = half;
196 }
197 remaining = high - low;
198 if (likely(remaining > 1))
199 remaining &= ~1U;
200
201 offset = prandom_u32() % remaining;
202 /* __inet_hash_connect() favors ports having @low parity
203 * We do the opposite to not pollute connect() users.
204 */
205 offset |= 1U;
206
207other_parity_scan:
208 port = low + offset;
209 for (i = 0; i < remaining; i += 2, port += 2) {
210 if (unlikely(port >= high))
211 port -= remaining;
212 if (inet_is_local_reserved_port(net, port))
213 continue;
214 head = &hinfo->bhash[inet_bhashfn(net, port,
215 hinfo->bhash_size)];
216 spin_lock_bh(&head->lock);
217 inet_bind_bucket_for_each(tb, &head->chain)
218 if (net_eq(ib_net(tb), net) && tb->port == port) {
219 if (!inet_csk_bind_conflict(sk, tb, false, false))
220 goto success;
221 goto next_port;
222 }
223 tb = NULL;
224 goto success;
225next_port:
226 spin_unlock_bh(&head->lock);
227 cond_resched();
228 }
229
230 offset--;
231 if (!(offset & 1))
232 goto other_parity_scan;
233
234 if (attempt_half == 1) {
235 /* OK we now try the upper half of the range */
236 attempt_half = 2;
237 goto other_half_scan;
238 }
239 return NULL;
240success:
241 *port_ret = port;
242 *tb_ret = tb;
243 return head;
244}
245
246static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
247 struct sock *sk)
248{
249 kuid_t uid = sock_i_uid(sk);
250
251 if (tb->fastreuseport <= 0)
252 return 0;
253 if (!sk->sk_reuseport)
254 return 0;
255 if (rcu_access_pointer(sk->sk_reuseport_cb))
256 return 0;
257 if (!uid_eq(tb->fastuid, uid))
258 return 0;
259 /* We only need to check the rcv_saddr if this tb was once marked
260 * without fastreuseport and then was reset, as we can only know that
261 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
262 * owners list.
263 */
264 if (tb->fastreuseport == FASTREUSEPORT_ANY)
265 return 1;
266#if IS_ENABLED(CONFIG_IPV6)
267 if (tb->fast_sk_family == AF_INET6)
268 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
269 inet6_rcv_saddr(sk),
270 tb->fast_rcv_saddr,
271 sk->sk_rcv_saddr,
272 tb->fast_ipv6_only,
273 ipv6_only_sock(sk), true);
274#endif
275 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
276 ipv6_only_sock(sk), true);
277}
278
279/* Obtain a reference to a local port for the given sock,
280 * if snum is zero it means select any available local port.
281 * We try to allocate an odd port (and leave even ports for connect())
282 */
283int inet_csk_get_port(struct sock *sk, unsigned short snum)
284{
285 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
286 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
287 int ret = 1, port = snum;
288 struct inet_bind_hashbucket *head;
289 struct net *net = sock_net(sk);
290 struct inet_bind_bucket *tb = NULL;
291 kuid_t uid = sock_i_uid(sk);
292
293 if (!port) {
294 head = inet_csk_find_open_port(sk, &tb, &port);
295 if (!head)
296 return ret;
297 if (!tb)
298 goto tb_not_found;
299 goto success;
300 }
301 head = &hinfo->bhash[inet_bhashfn(net, port,
302 hinfo->bhash_size)];
303 spin_lock_bh(&head->lock);
304 inet_bind_bucket_for_each(tb, &head->chain)
305 if (net_eq(ib_net(tb), net) && tb->port == port)
306 goto tb_found;
307tb_not_found:
308 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
309 net, head, port);
310 if (!tb)
311 goto fail_unlock;
312tb_found:
313 if (!hlist_empty(&tb->owners)) {
314 if (sk->sk_reuse == SK_FORCE_REUSE)
315 goto success;
316
317 if ((tb->fastreuse > 0 && reuse) ||
318 sk_reuseport_match(tb, sk))
319 goto success;
320 if (inet_csk_bind_conflict(sk, tb, true, true))
321 goto fail_unlock;
322 }
323success:
324 if (hlist_empty(&tb->owners)) {
325 tb->fastreuse = reuse;
326 if (sk->sk_reuseport) {
327 tb->fastreuseport = FASTREUSEPORT_ANY;
328 tb->fastuid = uid;
329 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
330 tb->fast_ipv6_only = ipv6_only_sock(sk);
331 tb->fast_sk_family = sk->sk_family;
332#if IS_ENABLED(CONFIG_IPV6)
333 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
334#endif
335 } else {
336 tb->fastreuseport = 0;
337 }
338 } else {
339 if (!reuse)
340 tb->fastreuse = 0;
341 if (sk->sk_reuseport) {
342 /* We didn't match or we don't have fastreuseport set on
343 * the tb, but we have sk_reuseport set on this socket
344 * and we know that there are no bind conflicts with
345 * this socket in this tb, so reset our tb's reuseport
346 * settings so that any subsequent sockets that match
347 * our current socket will be put on the fast path.
348 *
349 * If we reset we need to set FASTREUSEPORT_STRICT so we
350 * do extra checking for all subsequent sk_reuseport
351 * socks.
352 */
353 if (!sk_reuseport_match(tb, sk)) {
354 tb->fastreuseport = FASTREUSEPORT_STRICT;
355 tb->fastuid = uid;
356 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
357 tb->fast_ipv6_only = ipv6_only_sock(sk);
358 tb->fast_sk_family = sk->sk_family;
359#if IS_ENABLED(CONFIG_IPV6)
360 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
361#endif
362 }
363 } else {
364 tb->fastreuseport = 0;
365 }
366 }
367 if (!inet_csk(sk)->icsk_bind_hash)
368 inet_bind_hash(sk, tb, port);
369 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
370 ret = 0;
371
372fail_unlock:
373 spin_unlock_bh(&head->lock);
374 return ret;
375}
376EXPORT_SYMBOL_GPL(inet_csk_get_port);
377
378/*
379 * Wait for an incoming connection, avoid race conditions. This must be called
380 * with the socket locked.
381 */
382static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
383{
384 struct inet_connection_sock *icsk = inet_csk(sk);
385 DEFINE_WAIT(wait);
386 int err;
387
388 /*
389 * True wake-one mechanism for incoming connections: only
390 * one process gets woken up, not the 'whole herd'.
391 * Since we do not 'race & poll' for established sockets
392 * anymore, the common case will execute the loop only once.
393 *
394 * Subtle issue: "add_wait_queue_exclusive()" will be added
395 * after any current non-exclusive waiters, and we know that
396 * it will always _stay_ after any new non-exclusive waiters
397 * because all non-exclusive waiters are added at the
398 * beginning of the wait-queue. As such, it's ok to "drop"
399 * our exclusiveness temporarily when we get woken up without
400 * having to remove and re-insert us on the wait queue.
401 */
402 for (;;) {
403 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
404 TASK_INTERRUPTIBLE);
405 release_sock(sk);
406 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
407 timeo = schedule_timeout(timeo);
408 sched_annotate_sleep();
409 lock_sock(sk);
410 err = 0;
411 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
412 break;
413 err = -EINVAL;
414 if (sk->sk_state != TCP_LISTEN)
415 break;
416 err = sock_intr_errno(timeo);
417 if (signal_pending(current))
418 break;
419 err = -EAGAIN;
420 if (!timeo)
421 break;
422 }
423 finish_wait(sk_sleep(sk), &wait);
424 return err;
425}
426
427/*
428 * This will accept the next outstanding connection.
429 */
430struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
431{
432 struct inet_connection_sock *icsk = inet_csk(sk);
433 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
434 struct request_sock *req;
435 struct sock *newsk;
436 int error;
437
438 lock_sock(sk);
439
440 /* We need to make sure that this socket is listening,
441 * and that it has something pending.
442 */
443 error = -EINVAL;
444 if (sk->sk_state != TCP_LISTEN)
445 goto out_err;
446
447 /* Find already established connection */
448 if (reqsk_queue_empty(queue)) {
449 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
450
451 /* If this is a non blocking socket don't sleep */
452 error = -EAGAIN;
453 if (!timeo)
454 goto out_err;
455
456 error = inet_csk_wait_for_connect(sk, timeo);
457 if (error)
458 goto out_err;
459 }
460 req = reqsk_queue_remove(queue, sk);
461 newsk = req->sk;
462
463 if (sk->sk_protocol == IPPROTO_TCP &&
464 tcp_rsk(req)->tfo_listener) {
465 spin_lock_bh(&queue->fastopenq.lock);
466 if (tcp_rsk(req)->tfo_listener) {
467 /* We are still waiting for the final ACK from 3WHS
468 * so can't free req now. Instead, we set req->sk to
469 * NULL to signify that the child socket is taken
470 * so reqsk_fastopen_remove() will free the req
471 * when 3WHS finishes (or is aborted).
472 */
473 req->sk = NULL;
474 req = NULL;
475 }
476 spin_unlock_bh(&queue->fastopenq.lock);
477 }
478out:
479 release_sock(sk);
480 if (req)
481 reqsk_put(req);
482 return newsk;
483out_err:
484 newsk = NULL;
485 req = NULL;
486 *err = error;
487 goto out;
488}
489EXPORT_SYMBOL(inet_csk_accept);
490
491/*
492 * Using different timers for retransmit, delayed acks and probes
493 * We may wish use just one timer maintaining a list of expire jiffies
494 * to optimize.
495 */
496void inet_csk_init_xmit_timers(struct sock *sk,
497 void (*retransmit_handler)(struct timer_list *t),
498 void (*delack_handler)(struct timer_list *t),
499 void (*keepalive_handler)(struct timer_list *t))
500{
501 struct inet_connection_sock *icsk = inet_csk(sk);
502
503 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
504 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
505 timer_setup(&sk->sk_timer, keepalive_handler, 0);
506 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
507}
508EXPORT_SYMBOL(inet_csk_init_xmit_timers);
509
510void inet_csk_clear_xmit_timers(struct sock *sk)
511{
512 struct inet_connection_sock *icsk = inet_csk(sk);
513
514 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
515
516 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
517 sk_stop_timer(sk, &icsk->icsk_delack_timer);
518 sk_stop_timer(sk, &sk->sk_timer);
519}
520EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
521
522void inet_csk_delete_keepalive_timer(struct sock *sk)
523{
524 sk_stop_timer(sk, &sk->sk_timer);
525}
526EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
527
528void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
529{
530 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
531}
532EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
533
534struct dst_entry *inet_csk_route_req(const struct sock *sk,
535 struct flowi4 *fl4,
536 const struct request_sock *req)
537{
538 const struct inet_request_sock *ireq = inet_rsk(req);
539 struct net *net = read_pnet(&ireq->ireq_net);
540 struct ip_options_rcu *opt;
541 struct rtable *rt;
542
543 opt = ireq_opt_deref(ireq);
544
545 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
546 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
547 sk->sk_protocol, inet_sk_flowi_flags(sk),
548 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
549 ireq->ir_loc_addr, ireq->ir_rmt_port,
550 htons(ireq->ir_num), sk->sk_uid);
551 security_req_classify_flow(req, flowi4_to_flowi(fl4));
552 rt = ip_route_output_flow(net, fl4, sk);
553 if (IS_ERR(rt))
554 goto no_route;
555 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
556 goto route_err;
557 return &rt->dst;
558
559route_err:
560 ip_rt_put(rt);
561no_route:
562 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
563 return NULL;
564}
565EXPORT_SYMBOL_GPL(inet_csk_route_req);
566
567struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
568 struct sock *newsk,
569 const struct request_sock *req)
570{
571 const struct inet_request_sock *ireq = inet_rsk(req);
572 struct net *net = read_pnet(&ireq->ireq_net);
573 struct inet_sock *newinet = inet_sk(newsk);
574 struct ip_options_rcu *opt;
575 struct flowi4 *fl4;
576 struct rtable *rt;
577
578 opt = rcu_dereference(ireq->ireq_opt);
579 fl4 = &newinet->cork.fl.u.ip4;
580
581 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
582 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
583 sk->sk_protocol, inet_sk_flowi_flags(sk),
584 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
585 ireq->ir_loc_addr, ireq->ir_rmt_port,
586 htons(ireq->ir_num), sk->sk_uid);
587 security_req_classify_flow(req, flowi4_to_flowi(fl4));
588 rt = ip_route_output_flow(net, fl4, sk);
589 if (IS_ERR(rt))
590 goto no_route;
591 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
592 goto route_err;
593 return &rt->dst;
594
595route_err:
596 ip_rt_put(rt);
597no_route:
598 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
599 return NULL;
600}
601EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
602
603#if IS_ENABLED(CONFIG_IPV6)
604#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
605#else
606#define AF_INET_FAMILY(fam) true
607#endif
608
609/* Decide when to expire the request and when to resend SYN-ACK */
610static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
611 const int max_retries,
612 const u8 rskq_defer_accept,
613 int *expire, int *resend)
614{
615 if (!rskq_defer_accept) {
616 *expire = req->num_timeout >= thresh;
617 *resend = 1;
618 return;
619 }
620 *expire = req->num_timeout >= thresh &&
621 (!inet_rsk(req)->acked || req->num_timeout >= max_retries);
622 /*
623 * Do not resend while waiting for data after ACK,
624 * start to resend on end of deferring period to give
625 * last chance for data or ACK to create established socket.
626 */
627 *resend = !inet_rsk(req)->acked ||
628 req->num_timeout >= rskq_defer_accept - 1;
629}
630
631int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
632{
633 int err = req->rsk_ops->rtx_syn_ack(parent, req);
634
635 if (!err)
636 req->num_retrans++;
637 return err;
638}
639EXPORT_SYMBOL(inet_rtx_syn_ack);
640
641/* return true if req was found in the ehash table */
642static bool reqsk_queue_unlink(struct request_sock_queue *queue,
643 struct request_sock *req)
644{
645 struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo;
646 bool found = false;
647
648 if (sk_hashed(req_to_sk(req))) {
649 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
650
651 spin_lock(lock);
652 found = __sk_nulls_del_node_init_rcu(req_to_sk(req));
653 spin_unlock(lock);
654 }
655 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
656 reqsk_put(req);
657 return found;
658}
659
660void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
661{
662 if (reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req)) {
663 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
664 reqsk_put(req);
665 }
666}
667EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
668
669void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
670{
671 inet_csk_reqsk_queue_drop(sk, req);
672 reqsk_put(req);
673}
674EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
675
676static void reqsk_timer_handler(struct timer_list *t)
677{
678 struct request_sock *req = from_timer(req, t, rsk_timer);
679 struct sock *sk_listener = req->rsk_listener;
680 struct net *net = sock_net(sk_listener);
681 struct inet_connection_sock *icsk = inet_csk(sk_listener);
682 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
683 int qlen, expire = 0, resend = 0;
684 int max_retries, thresh;
685 u8 defer_accept;
686
687 if (inet_sk_state_load(sk_listener) != TCP_LISTEN)
688 goto drop;
689
690 max_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries;
691 thresh = max_retries;
692 /* Normally all the openreqs are young and become mature
693 * (i.e. converted to established socket) for first timeout.
694 * If synack was not acknowledged for 1 second, it means
695 * one of the following things: synack was lost, ack was lost,
696 * rtt is high or nobody planned to ack (i.e. synflood).
697 * When server is a bit loaded, queue is populated with old
698 * open requests, reducing effective size of queue.
699 * When server is well loaded, queue size reduces to zero
700 * after several minutes of work. It is not synflood,
701 * it is normal operation. The solution is pruning
702 * too old entries overriding normal timeout, when
703 * situation becomes dangerous.
704 *
705 * Essentially, we reserve half of room for young
706 * embrions; and abort old ones without pity, if old
707 * ones are about to clog our table.
708 */
709 qlen = reqsk_queue_len(queue);
710 if ((qlen << 1) > max(8U, sk_listener->sk_max_ack_backlog)) {
711 int young = reqsk_queue_len_young(queue) << 1;
712
713 while (thresh > 2) {
714 if (qlen < young)
715 break;
716 thresh--;
717 young <<= 1;
718 }
719 }
720 defer_accept = READ_ONCE(queue->rskq_defer_accept);
721 if (defer_accept)
722 max_retries = defer_accept;
723 syn_ack_recalc(req, thresh, max_retries, defer_accept,
724 &expire, &resend);
725 req->rsk_ops->syn_ack_timeout(req);
726 if (!expire &&
727 (!resend ||
728 !inet_rtx_syn_ack(sk_listener, req) ||
729 inet_rsk(req)->acked)) {
730 unsigned long timeo;
731
732 if (req->num_timeout++ == 0)
733 atomic_dec(&queue->young);
734 timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
735 mod_timer(&req->rsk_timer, jiffies + timeo);
736 return;
737 }
738drop:
739 inet_csk_reqsk_queue_drop_and_put(sk_listener, req);
740}
741
742static void reqsk_queue_hash_req(struct request_sock *req,
743 unsigned long timeout)
744{
745 req->num_retrans = 0;
746 req->num_timeout = 0;
747 req->sk = NULL;
748
749 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
750 mod_timer(&req->rsk_timer, jiffies + timeout);
751
752 inet_ehash_insert(req_to_sk(req), NULL);
753 /* before letting lookups find us, make sure all req fields
754 * are committed to memory and refcnt initialized.
755 */
756 smp_wmb();
757 refcount_set(&req->rsk_refcnt, 2 + 1);
758}
759
760void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
761 unsigned long timeout)
762{
763 reqsk_queue_hash_req(req, timeout);
764 inet_csk_reqsk_queue_added(sk);
765}
766EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
767
768/**
769 * inet_csk_clone_lock - clone an inet socket, and lock its clone
770 * @sk: the socket to clone
771 * @req: request_sock
772 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
773 *
774 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
775 */
776struct sock *inet_csk_clone_lock(const struct sock *sk,
777 const struct request_sock *req,
778 const gfp_t priority)
779{
780 struct sock *newsk = sk_clone_lock(sk, priority);
781
782 if (newsk) {
783 struct inet_connection_sock *newicsk = inet_csk(newsk);
784
785 inet_sk_set_state(newsk, TCP_SYN_RECV);
786 newicsk->icsk_bind_hash = NULL;
787
788 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
789 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
790 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
791
792 /* listeners have SOCK_RCU_FREE, not the children */
793 sock_reset_flag(newsk, SOCK_RCU_FREE);
794
795 inet_sk(newsk)->mc_list = NULL;
796
797 newsk->sk_mark = inet_rsk(req)->ir_mark;
798 atomic64_set(&newsk->sk_cookie,
799 atomic64_read(&inet_rsk(req)->ir_cookie));
800
801 newicsk->icsk_retransmits = 0;
802 newicsk->icsk_backoff = 0;
803 newicsk->icsk_probes_out = 0;
804
805 /* Deinitialize accept_queue to trap illegal accesses. */
806 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
807
808 security_inet_csk_clone(newsk, req);
809 }
810 return newsk;
811}
812EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
813
814/*
815 * At this point, there should be no process reference to this
816 * socket, and thus no user references at all. Therefore we
817 * can assume the socket waitqueue is inactive and nobody will
818 * try to jump onto it.
819 */
820void inet_csk_destroy_sock(struct sock *sk)
821{
822 WARN_ON(sk->sk_state != TCP_CLOSE);
823 WARN_ON(!sock_flag(sk, SOCK_DEAD));
824
825 /* It cannot be in hash table! */
826 WARN_ON(!sk_unhashed(sk));
827
828 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
829 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
830
831 sk->sk_prot->destroy(sk);
832
833 sk_stream_kill_queues(sk);
834
835 xfrm_sk_free_policy(sk);
836
837 sk_refcnt_debug_release(sk);
838
839 percpu_counter_dec(sk->sk_prot->orphan_count);
840
841 sock_put(sk);
842}
843EXPORT_SYMBOL(inet_csk_destroy_sock);
844
845/* This function allows to force a closure of a socket after the call to
846 * tcp/dccp_create_openreq_child().
847 */
848void inet_csk_prepare_forced_close(struct sock *sk)
849 __releases(&sk->sk_lock.slock)
850{
851 /* sk_clone_lock locked the socket and set refcnt to 2 */
852 bh_unlock_sock(sk);
853 sock_put(sk);
854
855 /* The below has to be done to allow calling inet_csk_destroy_sock */
856 sock_set_flag(sk, SOCK_DEAD);
857 percpu_counter_inc(sk->sk_prot->orphan_count);
858 inet_sk(sk)->inet_num = 0;
859}
860EXPORT_SYMBOL(inet_csk_prepare_forced_close);
861
862int inet_csk_listen_start(struct sock *sk, int backlog)
863{
864 struct inet_connection_sock *icsk = inet_csk(sk);
865 struct inet_sock *inet = inet_sk(sk);
866 int err = -EADDRINUSE;
867
868 reqsk_queue_alloc(&icsk->icsk_accept_queue);
869
870 sk->sk_max_ack_backlog = backlog;
871 sk->sk_ack_backlog = 0;
872 inet_csk_delack_init(sk);
873
874 /* There is race window here: we announce ourselves listening,
875 * but this transition is still not validated by get_port().
876 * It is OK, because this socket enters to hash table only
877 * after validation is complete.
878 */
879 inet_sk_state_store(sk, TCP_LISTEN);
880 if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
881 inet->inet_sport = htons(inet->inet_num);
882
883 sk_dst_reset(sk);
884 err = sk->sk_prot->hash(sk);
885
886 if (likely(!err))
887 return 0;
888 }
889
890 inet_sk_set_state(sk, TCP_CLOSE);
891 return err;
892}
893EXPORT_SYMBOL_GPL(inet_csk_listen_start);
894
895static void inet_child_forget(struct sock *sk, struct request_sock *req,
896 struct sock *child)
897{
898 sk->sk_prot->disconnect(child, O_NONBLOCK);
899
900 sock_orphan(child);
901
902 percpu_counter_inc(sk->sk_prot->orphan_count);
903
904 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
905 BUG_ON(tcp_sk(child)->fastopen_rsk != req);
906 BUG_ON(sk != req->rsk_listener);
907
908 /* Paranoid, to prevent race condition if
909 * an inbound pkt destined for child is
910 * blocked by sock lock in tcp_v4_rcv().
911 * Also to satisfy an assertion in
912 * tcp_v4_destroy_sock().
913 */
914 tcp_sk(child)->fastopen_rsk = NULL;
915 }
916 inet_csk_destroy_sock(child);
917}
918
919struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
920 struct request_sock *req,
921 struct sock *child)
922{
923 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
924
925 spin_lock(&queue->rskq_lock);
926 if (unlikely(sk->sk_state != TCP_LISTEN)) {
927 inet_child_forget(sk, req, child);
928 child = NULL;
929 } else {
930 req->sk = child;
931 req->dl_next = NULL;
932 if (queue->rskq_accept_head == NULL)
933 queue->rskq_accept_head = req;
934 else
935 queue->rskq_accept_tail->dl_next = req;
936 queue->rskq_accept_tail = req;
937 sk_acceptq_added(sk);
938 }
939 spin_unlock(&queue->rskq_lock);
940 return child;
941}
942EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
943
944struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
945 struct request_sock *req, bool own_req)
946{
947 if (own_req) {
948 inet_csk_reqsk_queue_drop(sk, req);
949 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
950 if (inet_csk_reqsk_queue_add(sk, req, child))
951 return child;
952 }
953 /* Too bad, another child took ownership of the request, undo. */
954 bh_unlock_sock(child);
955 sock_put(child);
956 return NULL;
957}
958EXPORT_SYMBOL(inet_csk_complete_hashdance);
959
960/*
961 * This routine closes sockets which have been at least partially
962 * opened, but not yet accepted.
963 */
964void inet_csk_listen_stop(struct sock *sk)
965{
966 struct inet_connection_sock *icsk = inet_csk(sk);
967 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
968 struct request_sock *next, *req;
969
970 /* Following specs, it would be better either to send FIN
971 * (and enter FIN-WAIT-1, it is normal close)
972 * or to send active reset (abort).
973 * Certainly, it is pretty dangerous while synflood, but it is
974 * bad justification for our negligence 8)
975 * To be honest, we are not able to make either
976 * of the variants now. --ANK
977 */
978 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
979 struct sock *child = req->sk;
980
981 local_bh_disable();
982 bh_lock_sock(child);
983 WARN_ON(sock_owned_by_user(child));
984 sock_hold(child);
985
986 inet_child_forget(sk, req, child);
987 reqsk_put(req);
988 bh_unlock_sock(child);
989 local_bh_enable();
990 sock_put(child);
991
992 cond_resched();
993 }
994 if (queue->fastopenq.rskq_rst_head) {
995 /* Free all the reqs queued in rskq_rst_head. */
996 spin_lock_bh(&queue->fastopenq.lock);
997 req = queue->fastopenq.rskq_rst_head;
998 queue->fastopenq.rskq_rst_head = NULL;
999 spin_unlock_bh(&queue->fastopenq.lock);
1000 while (req != NULL) {
1001 next = req->dl_next;
1002 reqsk_put(req);
1003 req = next;
1004 }
1005 }
1006 WARN_ON_ONCE(sk->sk_ack_backlog);
1007}
1008EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1009
1010void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1011{
1012 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1013 const struct inet_sock *inet = inet_sk(sk);
1014
1015 sin->sin_family = AF_INET;
1016 sin->sin_addr.s_addr = inet->inet_daddr;
1017 sin->sin_port = inet->inet_dport;
1018}
1019EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1020
1021#ifdef CONFIG_COMPAT
1022int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
1023 char __user *optval, int __user *optlen)
1024{
1025 const struct inet_connection_sock *icsk = inet_csk(sk);
1026
1027 if (icsk->icsk_af_ops->compat_getsockopt)
1028 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
1029 optval, optlen);
1030 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
1031 optval, optlen);
1032}
1033EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
1034
1035int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
1036 char __user *optval, unsigned int optlen)
1037{
1038 const struct inet_connection_sock *icsk = inet_csk(sk);
1039
1040 if (icsk->icsk_af_ops->compat_setsockopt)
1041 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
1042 optval, optlen);
1043 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1044 optval, optlen);
1045}
1046EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
1047#endif
1048
1049static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1050{
1051 const struct inet_sock *inet = inet_sk(sk);
1052 const struct ip_options_rcu *inet_opt;
1053 __be32 daddr = inet->inet_daddr;
1054 struct flowi4 *fl4;
1055 struct rtable *rt;
1056
1057 rcu_read_lock();
1058 inet_opt = rcu_dereference(inet->inet_opt);
1059 if (inet_opt && inet_opt->opt.srr)
1060 daddr = inet_opt->opt.faddr;
1061 fl4 = &fl->u.ip4;
1062 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
1063 inet->inet_saddr, inet->inet_dport,
1064 inet->inet_sport, sk->sk_protocol,
1065 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
1066 if (IS_ERR(rt))
1067 rt = NULL;
1068 if (rt)
1069 sk_setup_caps(sk, &rt->dst);
1070 rcu_read_unlock();
1071
1072 return &rt->dst;
1073}
1074
1075struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1076{
1077 struct dst_entry *dst = __sk_dst_check(sk, 0);
1078 struct inet_sock *inet = inet_sk(sk);
1079
1080 if (!dst) {
1081 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1082 if (!dst)
1083 goto out;
1084 }
1085 dst->ops->update_pmtu(dst, sk, NULL, mtu);
1086
1087 dst = __sk_dst_check(sk, 0);
1088 if (!dst)
1089 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1090out:
1091 return dst;
1092}
1093EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);
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
28const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
29EXPORT_SYMBOL(inet_csk_timer_bug_msg);
30#endif
31
32/*
33 * This struct holds the first and last local port number.
34 */
35struct local_ports sysctl_local_ports __read_mostly = {
36 .lock = __SEQLOCK_UNLOCKED(sysctl_local_ports.lock),
37 .range = { 32768, 61000 },
38};
39
40unsigned long *sysctl_local_reserved_ports;
41EXPORT_SYMBOL(sysctl_local_reserved_ports);
42
43void 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}
53EXPORT_SYMBOL(inet_get_local_port_range);
54
55int 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}
86EXPORT_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 */
91int 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
105again:
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 {
160have_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;
170tb_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 }
188tb_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;
201success:
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
207fail_unlock:
208 spin_unlock(&head->lock);
209fail:
210 local_bh_enable();
211 return ret;
212}
213EXPORT_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 */
219static 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 */
266struct 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);
297out:
298 release_sock(sk);
299 return newsk;
300out_err:
301 newsk = NULL;
302 *err = error;
303 goto out;
304}
305EXPORT_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 */
312void 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}
326EXPORT_SYMBOL(inet_csk_init_xmit_timers);
327
328void 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}
338EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
339
340void inet_csk_delete_keepalive_timer(struct sock *sk)
341{
342 sk_stop_timer(sk, &sk->sk_timer);
343}
344EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
345
346void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
347{
348 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
349}
350EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
351
352struct 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
374route_err:
375 ip_rt_put(rt);
376no_route:
377 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
378 return NULL;
379}
380EXPORT_SYMBOL_GPL(inet_csk_route_req);
381
382struct 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
407route_err:
408 ip_rt_put(rt);
409no_route:
410 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
411 return NULL;
412}
413EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
414
415static 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
427struct 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}
454EXPORT_SYMBOL_GPL(inet_csk_search_req);
455
456void 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}
467EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
468
469/* Only thing we need from tcp.h */
470extern int sysctl_tcp_synack_retries;
471
472
473/* Decide when to expire the request and when to resend SYN-ACK */
474static 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
495void 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}
589EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
590
591struct 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}
618EXPORT_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 */
626void 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}
648EXPORT_SYMBOL(inet_csk_destroy_sock);
649
650int 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}
682EXPORT_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 */
688void 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}
736EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
737
738void 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}
747EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
748
749#ifdef CONFIG_COMPAT
750int 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}
761EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
762
763int 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}
774EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
775#endif