summaryrefslogtreecommitdiffstats
path: root/net/ipv4/inet_connection_sock.c
blob: 38f23e721b80108d0a9ae3716fca5212cf8f737d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Support for INET connection oriented protocols.
 *
 * Authors:	See the TCP sources
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or(at your option) any later version.
 */

#include <linux/module.h>
#include <linux/jhash.h>

#include <net/inet_connection_sock.h>
#include <net/inet_hashtables.h>
#include <net/inet_timewait_sock.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/tcp_states.h>
#include <net/xfrm.h>

#ifdef INET_CSK_DEBUG
const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
EXPORT_SYMBOL(inet_csk_timer_bug_msg);
#endif

/*
 * This struct holds the first and last local port number.
 */
struct local_ports sysctl_local_ports __read_mostly = {
	.lock = SEQLOCK_UNLOCKED,
	.range = { 32768, 61000 },
};

unsigned long *sysctl_local_reserved_ports;
EXPORT_SYMBOL(sysctl_local_reserved_ports);

void inet_get_local_port_range(int *low, int *high)
{
	unsigned seq;
	do {
		seq = read_seqbegin(&sysctl_local_ports.lock);

		*low = sysctl_local_ports.range[0];
		*high = sysctl_local_ports.range[1];
	} while (read_seqretry(&sysctl_local_ports.lock, seq));
}
EXPORT_SYMBOL(inet_get_local_port_range);

int inet_csk_bind_conflict(const struct sock *sk,
			   const struct inet_bind_bucket *tb)
{
	struct sock *sk2;
	struct hlist_node *node;
	int reuse = sk->sk_reuse;

	/*
	 * Unlike other sk lookup places we do not check
	 * for sk_net here, since _all_ the socks listed
	 * in tb->owners list belong to the same net - the
	 * one this bucket belongs to.
	 */

	sk_for_each_bound(sk2, node, &tb->owners) {
		if (sk != sk2 &&
		    !inet_v6_ipv6only(sk2) &&
		    (!sk->sk_bound_dev_if ||
		     !sk2->sk_bound_dev_if ||
		     sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
			if (!reuse || !sk2->sk_reuse ||
			    sk2->sk_state == TCP_LISTEN) {
				const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
				if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||
				    sk2_rcv_saddr == sk_rcv_saddr(sk))
					break;
			}
		}
	}
	return node != NULL;
}
EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);

/* Obtain a reference to a local port for the given sock,
 * if snum is zero it means select any available local port.
 */
int inet_csk_get_port(struct sock *sk, unsigned short snum)
{
	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
	struct inet_bind_hashbucket *head;
	struct hlist_node *node;
	struct inet_bind_bucket *tb;
	int ret, attempts = 5;
	struct net *net = sock_net(sk);
	int smallest_size = -1, smallest_rover;

	local_bh_disable();
	if (!snum) {
		int remaining, rover, low, high;

again:
		inet_get_local_port_range(&low, &high);
		remaining = (high - low) + 1;
		smallest_rover = rover = net_random() % remaining + low;

		smallest_size = -1;
		do {
			if (inet_is_reserved_local_port(rover))
				goto next_nolock;
			head = &hashinfo->bhash[inet_bhashfn(net, rover,
					hashinfo->bhash_size)];
			spin_lock(&head->lock);
			inet_bind_bucket_for_each(tb, node, &head->chain)
				if (net_eq(ib_net(tb), net) && tb->port == rover) {
					if (tb->fastreuse > 0 &&
					    sk->sk_reuse &&
					    sk->sk_state != TCP_LISTEN &&
					    (tb->num_owners < smallest_size || smallest_size == -1)) {
						smallest_size = tb->num_owners;
						smallest_rover = rover;
						if (atomic_read(&hashinfo->bsockets) > (high - low) + 1) {
							spin_unlock(&head->lock);
							snum = smallest_rover;
							goto have_snum;
						}
					}
					goto next;
				}
			break;
		next:
			spin_unlock(&head->lock);
		next_nolock:
			if (++rover > high)
				rover = low;
		} while (--remaining > 0);

		/* Exhausted local port range during search?  It is not
		 * possible for us to be holding one of the bind hash
		 * locks if this test triggers, because if 'remaining'
		 * drops to zero, we broke out of the do/while loop at
		 * the top level, not from the 'break;' statement.
		 */
		ret = 1;
		if (remaining <= 0) {
			if (smallest_size != -1) {
				snum = smallest_rover;
				goto have_snum;
			}
			goto fail;
		}
		/* OK, here is the one we will use.  HEAD is
		 * non-NULL and we hold it's mutex.
		 */
		snum = rover;
	} else {
have_snum:
		head = &hashinfo->bhash[inet_bhashfn(net, snum,
				hashinfo->bhash_size)];
		spin_lock(&head->lock);
		inet_bind_bucket_for_each(tb, node, &head->chain)
			if (net_eq(ib_net(tb), net) && tb->port == snum)
				goto tb_found;
	}
	tb = NULL;
	goto tb_not_found;
tb_found:
	if (!hlist_empty(&tb->owners)) {
		if (tb->fastreuse > 0 &&
		    sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
		    smallest_size == -1) {
			goto success;
		} else {
			ret = 1;
			if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb)) {
				if (sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
				    smallest_size != -1 && --attempts >= 0) {
					spin_unlock(&head->lock);
					goto again;
				}
				goto fail_unlock;
			}
		}
	}
tb_not_found:
	ret = 1;
	if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
					net, head, snum)) == NULL)
		goto fail_unlock;
	if (hlist_empty(&tb->owners)) {
		if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
			tb->fastreuse = 1;
		else
			tb->fastreuse = 0;
	} else if (tb->fastreuse &&
		   (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
		tb->fastreuse = 0;
success:
	if (!inet_csk(sk)->icsk_bind_hash)
		inet_bind_hash(sk, tb, snum);
	WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
	ret = 0;

fail_unlock:
	spin_unlock(&head->lock);
fail:
	local_bh_enable();
	return ret;
}
EXPORT_SYMBOL_GPL(inet_csk_get_port);

/*
 * Wait for an incoming connection, avoid race conditions. This must be called
 * with the socket locked.
 */
static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	DEFINE_WAIT(wait);
	int err;

	/*
	 * True wake-one mechanism for incoming connections: only
	 * one process gets woken up, not the 'whole herd'.
	 * Since we do not 'race & poll' for established sockets
	 * anymore, the common case will execute the loop only once.
	 *
	 * Subtle issue: "add_wait_queue_exclusive()" will be added
	 * after any current non-exclusive waiters, and we know that
	 * it will always _stay_ after any new non-exclusive waiters
	 * because all non-exclusive waiters are added at the
	 * beginning of the wait-queue. As such, it's ok to "drop"
	 * our exclusiveness temporarily when we get woken up without
	 * having to remove and re-insert us on the wait queue.
	 */
	for (;;) {
		prepare_to_wait_exclusive(sk_sleep(sk), &wait,
					  TASK_INTERRUPTIBLE);
		release_sock(sk);
		if (reqsk_queue_empty(&icsk->icsk_accept_queue))
			timeo = schedule_timeout(timeo);
		lock_sock(sk);
		err = 0;
		if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
			break;
		err = -EINVAL;
		if (sk->sk_state != TCP_LISTEN)
			break;
		err = sock_intr_errno(timeo);
		if (signal_pending(current))
			break;
		err = -EAGAIN;
		if (!timeo)
			break;
	}
	finish_wait(sk_sleep(sk), &wait);
	return err;
}

/*
 * This will accept the next outstanding connection.
 */
struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct sock *newsk;
	int error;

	lock_sock(sk);

	/* We need to make sure that this socket is listening,
	 * and that it has something pending.
	 */
	error = -EINVAL;
	if (sk->sk_state != TCP_LISTEN)
		goto out_err;

	/* Find already established connection */
	if (reqsk_queue_empty(&icsk->icsk_accept_queue)) {
		long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);

		/* If this is a non blocking socket don't sleep */
		error = -EAGAIN;
		if (!timeo)
			goto out_err;

		error = inet_csk_wait_for_connect(sk, timeo);
		if (error)
			goto out_err;
	}

	newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
	WARN_ON(newsk->sk_state == TCP_SYN_RECV);
out:
	release_sock(sk);
	return newsk;
out_err:
	newsk = NULL;
	*err = error;
	goto out;
}
EXPORT_SYMBOL(inet_csk_accept);

/*
 * Using different timers for retransmit, delayed acks and probes
 * We may wish use just one timer maintaining a list of expire jiffies
 * to optimize.
 */
void inet_csk_init_xmit_timers(struct sock *sk,
			       void (*retransmit_handler)(unsigned long),
			       void (*delack_handler)(unsigned long),
			       void (*keepalive_handler)(unsigned long))
{
	struct inet_connection_sock *icsk = inet_csk(sk);

	setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
			(unsigned long)sk);
	setup_timer(&icsk->icsk_delack_timer, delack_handler,
			(unsigned long)sk);
	setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
	icsk->icsk_pending = icsk->icsk_ack.pending = 0;
}
EXPORT_SYMBOL(inet_csk_init_xmit_timers);

void inet_csk_clear_xmit_timers(struct sock *sk)
{
	struct inet_connection_sock *icsk = inet_csk(sk);

	icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;

	sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
	sk_stop_timer(sk, &icsk->icsk_delack_timer);
	sk_stop_timer(sk, &sk->sk_timer);
}
EXPORT_SYMBOL(inet_csk_clear_xmit_timers);

void inet_csk_delete_keepalive_timer(struct sock *sk)
{
	sk_stop_timer(sk, &sk->sk_timer);
}
EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);

void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
{
	sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
}
EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);

struct dst_entry *inet_csk_route_req(struct sock *sk,
				     const struct request_sock *req)
{
	struct rtable *rt;
	const struct inet_request_sock *ireq = inet_rsk(req);
	struct ip_options *opt = inet_rsk(req)->opt;
	struct flowi4 fl4 = {
		.flowi4_oif = sk->sk_bound_dev_if,
		.flowi4_mark = sk->sk_mark,
		.daddr = ((opt && opt->srr) ?
			  opt->faddr : ireq->rmt_addr),
		.saddr = ireq->loc_addr,
		.flowi4_tos = RT_CONN_FLAGS(sk),
		.flowi4_proto = sk->sk_protocol,
		.flowi4_flags = inet_sk_flowi_flags(sk),
		.fl4_sport = inet_sk(sk)->inet_sport,
		.fl4_dport = ireq->rmt_port,
	};
	struct net *net = sock_net(sk);

	security_req_classify_flow(req, flowi4_to_flowi(&fl4));
	rt = ip_route_output_flow(net, &fl4, sk);
	if (IS_ERR(rt))
		goto no_route;
	if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
		goto route_err;
	return &rt->dst;

route_err:
	ip_rt_put(rt);
no_route:
	IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
	return NULL;
}
EXPORT_SYMBOL_GPL(inet_csk_route_req);

static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
				 const u32 rnd, const u32 synq_hsize)
{
	return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
}

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
#else
#define AF_INET_FAMILY(fam) 1
#endif

struct request_sock *inet_csk_search_req(const struct sock *sk,
					 struct request_sock ***prevp,
					 const __be16 rport, const __be32 raddr,
					 const __be32 laddr)
{
	const struct inet_connection_sock *icsk = inet_csk(sk);
	struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
	struct request_sock *req, **prev;

	for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd,
						    lopt->nr_table_entries)];
	     (req = *prev) != NULL;
	     prev = &req->dl_next) {
		const struct inet_request_sock *ireq = inet_rsk(req);

		if (ireq->rmt_port == rport &&
		    ireq->rmt_addr == raddr &&
		    ireq->loc_addr == laddr &&
		    AF_INET_FAMILY(req->rsk_ops->family)) {
			WARN_ON(req->sk);
			*prevp = prev;
			break;
		}
	}

	return req;
}
EXPORT_SYMBOL_GPL(inet_csk_search_req);

void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
				   unsigned long timeout)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
	const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port,
				     lopt->hash_rnd, lopt->nr_table_entries);

	reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
	inet_csk_reqsk_queue_added(sk, timeout);
}
EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);

/* Only thing we need from tcp.h */
extern int sysctl_tcp_synack_retries;


/* Decide when to expire the request and when to resend SYN-ACK */
static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
				  const int max_retries,
				  const u8 rskq_defer_accept,
				  int *expire, int *resend)
{
	if (!rskq_defer_accept) {
		*expire = req->retrans >= thresh;
		*resend = 1;
		return;
	}
	*expire = req->retrans >= thresh &&
		  (!inet_rsk(req)->acked || req->retrans >= max_retries);
	/*
	 * Do not resend while waiting for data after ACK,
	 * start to resend on end of deferring period to give
	 * last chance for data or ACK to create established socket.
	 */
	*resend = !inet_rsk(req)->acked ||
		  req->retrans >= rskq_defer_accept - 1;
}

void inet_csk_reqsk_queue_prune(struct sock *parent,
				const unsigned long interval,
				const unsigned long timeout,
				const unsigned long max_rto)
{
	struct inet_connection_sock *icsk = inet_csk(parent);
	struct request_sock_queue *queue = &icsk->icsk_accept_queue;
	struct listen_sock *lopt = queue->listen_opt;
	int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
	int thresh = max_retries;
	unsigned long now = jiffies;
	struct request_sock **reqp, *req;
	int i, budget;

	if (lopt == NULL || lopt->qlen == 0)
		return;

	/* Normally all the openreqs are young and become mature
	 * (i.e. converted to established socket) for first timeout.
	 * If synack was not acknowledged for 3 seconds, it means
	 * one of the following things: synack was lost, ack was lost,
	 * rtt is high or nobody planned to ack (i.e. synflood).
	 * When server is a bit loaded, queue is populated with old
	 * open requests, reducing effective size of queue.
	 * When server is well loaded, queue size reduces to zero
	 * after several minutes of work. It is not synflood,
	 * it is normal operation. The solution is pruning
	 * too old entries overriding normal timeout, when
	 * situation becomes dangerous.
	 *
	 * Essentially, we reserve half of room for young
	 * embrions; and abort old ones without pity, if old
	 * ones are about to clog our table.
	 */
	if (lopt->qlen>>(lopt->max_qlen_log-1)) {
		int young = (lopt->qlen_young<<1);

		while (thresh > 2) {
			if (lopt->qlen < young)
				break;
			thresh--;
			young <<= 1;
		}
	}

	if (queue->rskq_defer_accept)
		max_retries = queue->rskq_defer_accept;

	budget = 2 * (lopt->nr_table_entries / (timeout / interval));
	i = lopt->clock_hand;

	do {
		reqp=&lopt->syn_table[i];
		while ((req = *reqp) != NULL) {
			if (time_after_eq(now, req->expires)) {
				int expire = 0, resend = 0;

				syn_ack_recalc(req, thresh, max_retries,
					       queue->rskq_defer_accept,
					       &expire, &resend);
				if (req->rsk_ops->syn_ack_timeout)
					req->rsk_ops->syn_ack_timeout(parent, req);
				if (!expire &&
				    (!resend ||
				     !req->rsk_ops->rtx_syn_ack(parent, req, NULL) ||
				     inet_rsk(req)->acked)) {
					unsigned long timeo;

					if (req->retrans++ == 0)
						lopt->qlen_young--;
					timeo = min((timeout << req->retrans), max_rto);
					req->expires = now + timeo;
					reqp = &req->dl_next;
					continue;
				}

				/* Drop this request */
				inet_csk_reqsk_queue_unlink(parent, req, reqp);
				reqsk_queue_removed(queue, req);
				reqsk_free(req);
				continue;
			}
			reqp = &req->dl_next;
		}

		i = (i + 1) & (lopt->nr_table_entries - 1);

	} while (--budget > 0);

	lopt->clock_hand = i;

	if (lopt->qlen)
		inet_csk_reset_keepalive_timer(parent, interval);
}
EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);

struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req,
			    const gfp_t priority)
{
	struct sock *newsk = sk_clone(sk, priority);

	if (newsk != NULL) {
		struct inet_connection_sock *newicsk = inet_csk(newsk);

		newsk->sk_state = TCP_SYN_RECV;
		newicsk->icsk_bind_hash = NULL;

		inet_sk(newsk)->inet_dport = inet_rsk(req)->rmt_port;
		inet_sk(newsk)->inet_num = ntohs(inet_rsk(req)->loc_port);
		inet_sk(newsk)->inet_sport = inet_rsk(req)->loc_port;
		newsk->sk_write_space = sk_stream_write_space;

		newicsk->icsk_retransmits = 0;
		newicsk->icsk_backoff	  = 0;
		newicsk->icsk_probes_out  = 0;

		/* Deinitialize accept_queue to trap illegal accesses. */
		memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));

		security_inet_csk_clone(newsk, req);
	}
	return newsk;
}
EXPORT_SYMBOL_GPL(inet_csk_clone);

/*
 * At this point, there should be no process reference to this
 * socket, and thus no user references at all.  Therefore we
 * can assume the socket waitqueue is inactive and nobody will
 * try to jump onto it.
 */
void inet_csk_destroy_sock(struct sock *sk)
{
	WARN_ON(sk->sk_state != TCP_CLOSE);
	WARN_ON(!sock_flag(sk, SOCK_DEAD));

	/* It cannot be in hash table! */
	WARN_ON(!sk_unhashed(sk));

	/* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
	WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);

	sk->sk_prot->destroy(sk);

	sk_stream_kill_queues(sk);

	xfrm_sk_free_policy(sk);

	sk_refcnt_debug_release(sk);

	percpu_counter_dec(sk->sk_prot->orphan_count);
	sock_put(sk);
}
EXPORT_SYMBOL(inet_csk_destroy_sock);

int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
{
	struct inet_sock *inet = inet_sk(sk);
	struct inet_connection_sock *icsk = inet_csk(sk);
	int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);

	if (rc != 0)
		return rc;

	sk->sk_max_ack_backlog = 0;
	sk->sk_ack_backlog = 0;
	inet_csk_delack_init(sk);

	/* There is race window here: we announce ourselves listening,
	 * but this transition is still not validated by get_port().
	 * It is OK, because this socket enters to hash table only
	 * after validation is complete.
	 */
	sk->sk_state = TCP_LISTEN;
	if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
		inet->inet_sport = htons(inet->inet_num);

		sk_dst_reset(sk);
		sk->sk_prot->hash(sk);

		return 0;
	}

	sk->sk_state = TCP_CLOSE;
	__reqsk_queue_destroy(&icsk->icsk_accept_queue);
	return -EADDRINUSE;
}
EXPORT_SYMBOL_GPL(inet_csk_listen_start);

/*
 *	This routine closes sockets which have been at least partially
 *	opened, but not yet accepted.
 */
void inet_csk_listen_stop(struct sock *sk)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct request_sock *acc_req;
	struct request_sock *req;

	inet_csk_delete_keepalive_timer(sk);

	/* make all the listen_opt local to us */
	acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue);

	/* Following specs, it would be better either to send FIN
	 * (and enter FIN-WAIT-1, it is normal close)
	 * or to send active reset (abort).
	 * Certainly, it is pretty dangerous while synflood, but it is
	 * bad justification for our negligence 8)
	 * To be honest, we are not able to make either
	 * of the variants now.			--ANK
	 */
	reqsk_queue_destroy(&icsk->icsk_accept_queue);

	while ((req = acc_req) != NULL) {
		struct sock *child = req->sk;

		acc_req = req->dl_next;

		local_bh_disable();
		bh_lock_sock(child);
		WARN_ON(sock_owned_by_user(child));
		sock_hold(child);

		sk->sk_prot->disconnect(child, O_NONBLOCK);

		sock_orphan(child);

		percpu_counter_inc(sk->sk_prot->orphan_count);

		inet_csk_destroy_sock(child);

		bh_unlock_sock(child);
		local_bh_enable();
		sock_put(child);

		sk_acceptq_removed(sk);
		__reqsk_free(req);
	}
	WARN_ON(sk->sk_ack_backlog);
}
EXPORT_SYMBOL_GPL(inet_csk_listen_stop);

void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
{
	struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
	const struct inet_sock *inet = inet_sk(sk);

	sin->sin_family		= AF_INET;
	sin->sin_addr.s_addr	= inet->inet_daddr;
	sin->sin_port		= inet->inet_dport;
}
EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);

#ifdef CONFIG_COMPAT
int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
			       char __user *optval, int __user *optlen)
{
	const struct inet_connection_sock *icsk = inet_csk(sk);

	if (icsk->icsk_af_ops->compat_getsockopt != NULL)
		return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
							    optval, optlen);
	return icsk->icsk_af_ops->getsockopt(sk, level, optname,
					     optval, optlen);
}
EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);

int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
			       char __user *optval, unsigned int optlen)
{
	const struct inet_connection_sock *icsk = inet_csk(sk);

	if (icsk->icsk_af_ops->compat_setsockopt != NULL)
		return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
							    optval, optlen);
	return icsk->icsk_af_ops->setsockopt(sk, level, optname,
					     optval, optlen);
}
EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
#endif
OpenPOWER on IntegriCloud