aboutsummaryrefslogtreecommitdiff
path: root/net/dccp/proto.c
blob: 46dd489f66cf2f4de32a422943314c3be199d273 (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
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
/*
 *  net/dccp/proto.c
 *
 *  An implementation of the DCCP protocol
 *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 *	This program is free software; you can redistribute it and/or modify it
 *	under the terms of the GNU General Public License version 2 as
 *	published by the Free Software Foundation.
 */

#include <linux/config.h>
#include <linux/dccp.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/in.h>
#include <linux/if_arp.h>
#include <linux/init.h>
#include <linux/random.h>
#include <net/checksum.h>

#include <net/inet_common.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/sock.h>
#include <net/xfrm.h>

#include <asm/semaphore.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/dccp.h>

#include "ccid.h"
#include "dccp.h"

DEFINE_SNMP_STAT(struct dccp_mib, dccp_statistics);

atomic_t dccp_orphan_count = ATOMIC_INIT(0);

static struct net_protocol dccp_protocol = {
	.handler	= dccp_v4_rcv,
	.err_handler	= dccp_v4_err,
};

const char *dccp_packet_name(const int type)
{
	static const char *dccp_packet_names[] = {
		[DCCP_PKT_REQUEST]  = "REQUEST",
		[DCCP_PKT_RESPONSE] = "RESPONSE",
		[DCCP_PKT_DATA]	    = "DATA",
		[DCCP_PKT_ACK]	    = "ACK",
		[DCCP_PKT_DATAACK]  = "DATAACK",
		[DCCP_PKT_CLOSEREQ] = "CLOSEREQ",
		[DCCP_PKT_CLOSE]    = "CLOSE",
		[DCCP_PKT_RESET]    = "RESET",
		[DCCP_PKT_SYNC]	    = "SYNC",
		[DCCP_PKT_SYNCACK]  = "SYNCACK",
	};

	if (type >= DCCP_NR_PKT_TYPES)
		return "INVALID";
	else
		return dccp_packet_names[type];
}

EXPORT_SYMBOL_GPL(dccp_packet_name);

const char *dccp_state_name(const int state)
{
	static char *dccp_state_names[] = {
	[DCCP_OPEN]	  = "OPEN",
	[DCCP_REQUESTING] = "REQUESTING",
	[DCCP_PARTOPEN]	  = "PARTOPEN",
	[DCCP_LISTEN]	  = "LISTEN",
	[DCCP_RESPOND]	  = "RESPOND",
	[DCCP_CLOSING]	  = "CLOSING",
	[DCCP_TIME_WAIT]  = "TIME_WAIT",
	[DCCP_CLOSED]	  = "CLOSED",
	};

	if (state >= DCCP_MAX_STATES)
		return "INVALID STATE!";
	else
		return dccp_state_names[state];
}

EXPORT_SYMBOL_GPL(dccp_state_name);

static inline int dccp_listen_start(struct sock *sk)
{
	dccp_sk(sk)->dccps_role = DCCP_ROLE_LISTEN;
	return inet_csk_listen_start(sk, TCP_SYNQ_HSIZE);
}

int dccp_disconnect(struct sock *sk, int flags)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct inet_sock *inet = inet_sk(sk);
	int err = 0;
	const int old_state = sk->sk_state;

	if (old_state != DCCP_CLOSED)
		dccp_set_state(sk, DCCP_CLOSED);

	/* ABORT function of RFC793 */
	if (old_state == DCCP_LISTEN) {
		inet_csk_listen_stop(sk);
	/* FIXME: do the active reset thing */
	} else if (old_state == DCCP_REQUESTING)
		sk->sk_err = ECONNRESET;

	dccp_clear_xmit_timers(sk);
	__skb_queue_purge(&sk->sk_receive_queue);
	if (sk->sk_send_head != NULL) {
		__kfree_skb(sk->sk_send_head);
		sk->sk_send_head = NULL;
	}

	inet->dport = 0;

	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
		inet_reset_saddr(sk);

	sk->sk_shutdown = 0;
	sock_reset_flag(sk, SOCK_DONE);

	icsk->icsk_backoff = 0;
	inet_csk_delack_init(sk);
	__sk_dst_reset(sk);

	BUG_TRAP(!inet->num || icsk->icsk_bind_hash);

	sk->sk_error_report(sk);
	return err;
}

int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
	dccp_pr_debug("entry\n");
	return -ENOIOCTLCMD;
}

int dccp_setsockopt(struct sock *sk, int level, int optname,
		    char *optval, int optlen)
{
	dccp_pr_debug("entry\n");

	if (level != SOL_DCCP)
		return ip_setsockopt(sk, level, optname, optval, optlen);

	return -EOPNOTSUPP;
}

int dccp_getsockopt(struct sock *sk, int level, int optname,
		    char *optval, int *optlen)
{
	dccp_pr_debug("entry\n");

	if (level != SOL_DCCP)
		return ip_getsockopt(sk, level, optname, optval, optlen);

	return -EOPNOTSUPP;
}

int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		 size_t len)
{
	const struct dccp_sock *dp = dccp_sk(sk);
	const int flags = msg->msg_flags;
	const int noblock = flags & MSG_DONTWAIT;
	struct sk_buff *skb;
	int rc, size;
	long timeo;

	if (len > dp->dccps_mss_cache)
		return -EMSGSIZE;

	lock_sock(sk);
	timeo = sock_sndtimeo(sk, noblock);

	/*
	 * We have to use sk_stream_wait_connect here to set sk_write_pending,
	 * so that the trick in dccp_rcv_request_sent_state_process.
	 */
	/* Wait for a connection to finish. */
	if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN | DCCPF_CLOSING))
		if ((rc = sk_stream_wait_connect(sk, &timeo)) != 0)
			goto out_release;

	size = sk->sk_prot->max_header + len;
	release_sock(sk);
	skb = sock_alloc_send_skb(sk, size, noblock, &rc);
	lock_sock(sk);
	if (skb == NULL)
		goto out_release;

	skb_reserve(skb, sk->sk_prot->max_header);
	rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
	if (rc != 0)
		goto out_discard;

	rc = dccp_write_xmit(sk, skb, len);
out_release:
	release_sock(sk);
	return rc ? : len;
out_discard:
	kfree_skb(skb);
	goto out_release;
}

EXPORT_SYMBOL(dccp_sendmsg);

int dccp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		 size_t len, int nonblock, int flags, int *addr_len)
{
	const struct dccp_hdr *dh;
	int copied = 0;
	unsigned long used;
	int err;
	int target;		/* Read at least this many bytes */
	long timeo;

	lock_sock(sk);

	err = -ENOTCONN;
	if (sk->sk_state == DCCP_LISTEN)
		goto out;

	timeo = sock_rcvtimeo(sk, nonblock);

	/* Urgent data needs to be handled specially. */
	if (flags & MSG_OOB)
		goto recv_urg;

	/* FIXME */
#if 0
	seq = &tp->copied_seq;
	if (flags & MSG_PEEK) {
		peek_seq = tp->copied_seq;
		seq = &peek_seq;
	}
#endif

	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);

	do {
		struct sk_buff *skb;
		u32 offset;

	/* FIXME */
#if 0
		/*
		 * Are we at urgent data? Stop if we have read anything or
		 * have SIGURG pending.
		 */
		if (tp->urg_data && tp->urg_seq == *seq) {
			if (copied)
				break;
			if (signal_pending(current)) {
				copied = timeo ? sock_intr_errno(timeo) :
						 -EAGAIN;
				break;
			}
		}
#endif

		/* Next get a buffer. */

		skb = skb_peek(&sk->sk_receive_queue);
		do {
			if (!skb)
				break;

			offset = 0;
			dh = dccp_hdr(skb);

			if (dh->dccph_type == DCCP_PKT_DATA ||
			    dh->dccph_type == DCCP_PKT_DATAACK)
				goto found_ok_skb;

			if (dh->dccph_type == DCCP_PKT_RESET ||
			    dh->dccph_type == DCCP_PKT_CLOSE) {
				dccp_pr_debug("found fin ok!\n");
				goto found_fin_ok;
			}
			dccp_pr_debug("packet_type=%s\n",
				      dccp_packet_name(dh->dccph_type));
			BUG_TRAP(flags & MSG_PEEK);
			skb = skb->next;
		} while (skb != (struct sk_buff *)&sk->sk_receive_queue);

		/* Well, if we have backlog, try to process it now yet. */
		if (copied >= target && !sk->sk_backlog.tail)
			break;

		if (copied) {
			if (sk->sk_err ||
			    sk->sk_state == DCCP_CLOSED ||
			    (sk->sk_shutdown & RCV_SHUTDOWN) ||
			    !timeo ||
			    signal_pending(current) ||
			    (flags & MSG_PEEK))
				break;
		} else {
			if (sock_flag(sk, SOCK_DONE))
				break;

			if (sk->sk_err) {
				copied = sock_error(sk);
				break;
			}

			if (sk->sk_shutdown & RCV_SHUTDOWN)
				break;

			if (sk->sk_state == DCCP_CLOSED) {
				if (!sock_flag(sk, SOCK_DONE)) {
					/* This occurs when user tries to read
					 * from never connected socket.
					 */
					copied = -ENOTCONN;
					break;
				}
				break;
			}

			if (!timeo) {
				copied = -EAGAIN;
				break;
			}

			if (signal_pending(current)) {
				copied = sock_intr_errno(timeo);
				break;
			}
		}

		/* FIXME: cleanup_rbuf(sk, copied); */

		if (copied >= target) {
			/* Do not sleep, just process backlog. */
			release_sock(sk);
			lock_sock(sk);
		} else
			sk_wait_data(sk, &timeo);

		continue;

	found_ok_skb:
		/* Ok so how much can we use? */
		used = skb->len - offset;
		if (len < used)
			used = len;

		if (!(flags & MSG_TRUNC)) {
			err = skb_copy_datagram_iovec(skb, offset,
						      msg->msg_iov, used);
			if (err) {
				/* Exception. Bailout! */
				if (!copied)
					copied = -EFAULT;
				break;
			}
		}

		copied += used;
		len -= used;

		/* FIXME: tcp_rcv_space_adjust(sk); */

//skip_copy:
		if (used + offset < skb->len)
			continue;

		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
		continue;
	found_fin_ok:
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
		break;
		
	} while (len > 0);

	/* According to UNIX98, msg_name/msg_namelen are ignored
	 * on connected socket. I was just happy when found this 8) --ANK
	 */

	/* Clean up data we have read: This will do ACK frames. */
	/* FIXME: cleanup_rbuf(sk, copied); */

	release_sock(sk);
	return copied;

out:
	release_sock(sk);
	return err;

recv_urg:
	/* FIXME: err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len); */
	goto out;
}

static int inet_dccp_listen(struct socket *sock, int backlog)
{
	struct sock *sk = sock->sk;
	unsigned char old_state;
	int err;

	lock_sock(sk);

	err = -EINVAL;
	if (sock->state != SS_UNCONNECTED || sock->type != SOCK_DCCP)
		goto out;

	old_state = sk->sk_state;
	if (!((1 << old_state) & (DCCPF_CLOSED | DCCPF_LISTEN)))
		goto out;

	/* Really, if the socket is already in listen state
	 * we can only allow the backlog to be adjusted.
	 */
	if (old_state != DCCP_LISTEN) {
		/*
		 * FIXME: here it probably should be sk->sk_prot->listen_start
		 * see tcp_listen_start
		 */
		err = dccp_listen_start(sk);
		if (err)
			goto out;
	}
	sk->sk_max_ack_backlog = backlog;
	err = 0;

out:
	release_sock(sk);
	return err;
}

static const unsigned char dccp_new_state[] = {
	/* current state:   new state:      action:	*/
	[0]		  = DCCP_CLOSED,
	[DCCP_OPEN] 	  = DCCP_CLOSING | DCCP_ACTION_FIN,
	[DCCP_REQUESTING] = DCCP_CLOSED,
	[DCCP_PARTOPEN]	  = DCCP_CLOSING | DCCP_ACTION_FIN,
	[DCCP_LISTEN]	  = DCCP_CLOSED,
	[DCCP_RESPOND]	  = DCCP_CLOSED,
	[DCCP_CLOSING]	  = DCCP_CLOSED,
	[DCCP_TIME_WAIT]  = DCCP_CLOSED,
	[DCCP_CLOSED]	  = DCCP_CLOSED,
};

static int dccp_close_state(struct sock *sk)
{
	const int next = dccp_new_state[sk->sk_state];
	const int ns = next & DCCP_STATE_MASK;

	if (ns != sk->sk_state)
		dccp_set_state(sk, ns);

	return next & DCCP_ACTION_FIN;
}

void dccp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;

	lock_sock(sk);

	sk->sk_shutdown = SHUTDOWN_MASK;

	if (sk->sk_state == DCCP_LISTEN) {
		dccp_set_state(sk, DCCP_CLOSED);

		/* Special case. */
		inet_csk_listen_stop(sk);

		goto adjudge_to_death;
	}

	/*
	 * We need to flush the recv. buffs.  We do this only on the
	 * descriptor close, not protocol-sourced closes, because the
	  *reader process may not have drained the data yet!
	 */
	/* FIXME: check for unread data */
	while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
		__kfree_skb(skb);
	}

	if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
	} else if (dccp_close_state(sk)) {
		dccp_send_close(sk);
	}

	sk_stream_wait_close(sk, timeout);

adjudge_to_death:
	release_sock(sk);
	/*
	 * Now socket is owned by kernel and we acquire BH lock
	 * to finish close. No need to check for user refs.
	 */
	local_bh_disable();
	bh_lock_sock(sk);
	BUG_TRAP(!sock_owned_by_user(sk));

	sock_hold(sk);
	sock_orphan(sk);
						
	if (sk->sk_state != DCCP_CLOSED)
		dccp_set_state(sk, DCCP_CLOSED);

	atomic_inc(&dccp_orphan_count);
	if (sk->sk_state == DCCP_CLOSED)
		inet_csk_destroy_sock(sk);

	/* Otherwise, socket is reprieved until protocol close. */

	bh_unlock_sock(sk);
	local_bh_enable();
	sock_put(sk);
}

void dccp_shutdown(struct sock *sk, int how)
{
	dccp_pr_debug("entry\n");
}

struct proto_ops inet_dccp_ops = {
	.family		= PF_INET,
	.owner		= THIS_MODULE,
	.release	= inet_release,
	.bind		= inet_bind,
	.connect	= inet_stream_connect,
	.socketpair	= sock_no_socketpair,
	.accept		= inet_accept,
	.getname	= inet_getname,
	.poll		= sock_no_poll,
	.ioctl		= inet_ioctl,
	/* FIXME: work on inet_listen to rename it to sock_common_listen */
	.listen		= inet_dccp_listen,
	.shutdown	= inet_shutdown,
	.setsockopt	= sock_common_setsockopt,
	.getsockopt	= sock_common_getsockopt,
	.sendmsg	= inet_sendmsg,
	.recvmsg	= sock_common_recvmsg,
	.mmap		= sock_no_mmap,
	.sendpage	= sock_no_sendpage,
};

extern struct net_proto_family inet_family_ops;

static struct inet_protosw dccp_v4_protosw = {
	.type		= SOCK_DCCP,
	.protocol	= IPPROTO_DCCP,
	.prot		= &dccp_v4_prot,
	.ops		= &inet_dccp_ops,
	.capability	= -1,
	.no_check	= 0,
	.flags		= 0,
};

/*
 * This is the global socket data structure used for responding to
 * the Out-of-the-blue (OOTB) packets. A control sock will be created
 * for this socket at the initialization time.
 */
struct socket *dccp_ctl_socket;

static char dccp_ctl_socket_err_msg[] __initdata =
	KERN_ERR "DCCP: Failed to create the control socket.\n";

static int __init dccp_ctl_sock_init(void)
{
	int rc = sock_create_kern(PF_INET, SOCK_DCCP, IPPROTO_DCCP,
				  &dccp_ctl_socket);
	if (rc < 0)
		printk(dccp_ctl_socket_err_msg);
	else {
		dccp_ctl_socket->sk->sk_allocation = GFP_ATOMIC;
		inet_sk(dccp_ctl_socket->sk)->uc_ttl = -1;

		/* Unhash it so that IP input processing does not even
		 * see it, we do not wish this socket to see incoming
		 * packets.
		 */
		dccp_ctl_socket->sk->sk_prot->unhash(dccp_ctl_socket->sk);
	}

	return rc;
}

static void __exit dccp_ctl_sock_exit(void)
{
	if (dccp_ctl_socket != NULL)
		sock_release(dccp_ctl_socket);
}

static int __init init_dccp_v4_mibs(void)
{
	int rc = -ENOMEM;

	dccp_statistics[0] = alloc_percpu(struct dccp_mib);
	if (dccp_statistics[0] == NULL)
		goto out;

	dccp_statistics[1] = alloc_percpu(struct dccp_mib);
	if (dccp_statistics[1] == NULL)
		goto out_free_one;

	rc = 0;
out:
	return rc;
out_free_one:
	free_percpu(dccp_statistics[0]);
	dccp_statistics[0] = NULL;
	goto out;

}

static int thash_entries;
module_param(thash_entries, int, 0444);
MODULE_PARM_DESC(thash_entries, "Number of ehash buckets");

int dccp_debug;
module_param(dccp_debug, int, 0444);
MODULE_PARM_DESC(dccp_debug, "Enable debug messages");

static int __init dccp_init(void)
{
	unsigned long goal;
	int ehash_order, bhash_order, i;
	int rc = proto_register(&dccp_v4_prot, 1);

	if (rc)
		goto out;

	dccp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("dccp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
				  SLAB_HWCACHE_ALIGN, NULL, NULL);
	if (!dccp_hashinfo.bind_bucket_cachep)
		goto out_proto_unregister;

	/*
	 * Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
	if (num_physpages >= (128 * 1024))
		goal = num_physpages >> (21 - PAGE_SHIFT);
	else
		goal = num_physpages >> (23 - PAGE_SHIFT);

	if (thash_entries)
		goal = (thash_entries *
			sizeof(struct inet_ehash_bucket)) >> PAGE_SHIFT;
	for (ehash_order = 0; (1UL << ehash_order) < goal; ehash_order++)
		;
	do {
		dccp_hashinfo.ehash_size = (1UL << ehash_order) * PAGE_SIZE /
					sizeof(struct inet_ehash_bucket);
		dccp_hashinfo.ehash_size >>= 1;
		while (dccp_hashinfo.ehash_size &
		       (dccp_hashinfo.ehash_size - 1))
			dccp_hashinfo.ehash_size--;
		dccp_hashinfo.ehash = (struct inet_ehash_bucket *)
			__get_free_pages(GFP_ATOMIC, ehash_order);
	} while (!dccp_hashinfo.ehash && --ehash_order > 0);

	if (!dccp_hashinfo.ehash) {
		printk(KERN_CRIT "Failed to allocate DCCP "
				 "established hash table\n");
		goto out_free_bind_bucket_cachep;
	}

	for (i = 0; i < (dccp_hashinfo.ehash_size << 1); i++) {
		rwlock_init(&dccp_hashinfo.ehash[i].lock);
		INIT_HLIST_HEAD(&dccp_hashinfo.ehash[i].chain);
	}

	bhash_order = ehash_order;

	do {
		dccp_hashinfo.bhash_size = (1UL << bhash_order) * PAGE_SIZE /
					sizeof(struct inet_bind_hashbucket);
		if ((dccp_hashinfo.bhash_size > (64 * 1024)) &&
		    bhash_order > 0)
			continue;
		dccp_hashinfo.bhash = (struct inet_bind_hashbucket *)
			__get_free_pages(GFP_ATOMIC, bhash_order);
	} while (!dccp_hashinfo.bhash && --bhash_order >= 0);

	if (!dccp_hashinfo.bhash) {
		printk(KERN_CRIT "Failed to allocate DCCP bind hash table\n");
		goto out_free_dccp_ehash;
	}

	for (i = 0; i < dccp_hashinfo.bhash_size; i++) {
		spin_lock_init(&dccp_hashinfo.bhash[i].lock);
		INIT_HLIST_HEAD(&dccp_hashinfo.bhash[i].chain);
	}

	if (init_dccp_v4_mibs())
		goto out_free_dccp_bhash;

	rc = -EAGAIN;
	if (inet_add_protocol(&dccp_protocol, IPPROTO_DCCP))
		goto out_free_dccp_v4_mibs;

	inet_register_protosw(&dccp_v4_protosw);

	rc = dccp_ctl_sock_init();
	if (rc)
		goto out_unregister_protosw;
out:
	return rc;
out_unregister_protosw:
	inet_unregister_protosw(&dccp_v4_protosw);
	inet_del_protocol(&dccp_protocol, IPPROTO_DCCP);
out_free_dccp_v4_mibs:
	free_percpu(dccp_statistics[0]);
	free_percpu(dccp_statistics[1]);
	dccp_statistics[0] = dccp_statistics[1] = NULL;
out_free_dccp_bhash:
	free_pages((unsigned long)dccp_hashinfo.bhash, bhash_order);
	dccp_hashinfo.bhash = NULL;
out_free_dccp_ehash:
	free_pages((unsigned long)dccp_hashinfo.ehash, ehash_order);
	dccp_hashinfo.ehash = NULL;
out_free_bind_bucket_cachep:
	kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
	dccp_hashinfo.bind_bucket_cachep = NULL;
out_proto_unregister:
	proto_unregister(&dccp_v4_prot);
	goto out;
}

static const char dccp_del_proto_err_msg[] __exitdata =
	KERN_ERR "can't remove dccp net_protocol\n";

static void __exit dccp_fini(void)
{
	dccp_ctl_sock_exit();

	inet_unregister_protosw(&dccp_v4_protosw);

	if (inet_del_protocol(&dccp_protocol, IPPROTO_DCCP) < 0)
		printk(dccp_del_proto_err_msg);

	/* Free the control endpoint.  */
	sock_release(dccp_ctl_socket);

	proto_unregister(&dccp_v4_prot);

	kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
}

module_init(dccp_init);
module_exit(dccp_fini);

/*
 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
 * values directly, Also cover the case where the protocol is not specified,
 * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
 */
MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-33-type-6");
MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-0-type-6");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@conectiva.com.br>");
MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");