summaryrefslogtreecommitdiff
path: root/net/l2tp/l2tp_ip.c
blob: 55670ec3cd0f916143759cbc73320cf85b7ef196 (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
/*
 * L2TPv3 IP encapsulation support
 *
 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
 *
 *	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/icmp.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/random.h>
#include <linux/socket.h>
#include <linux/l2tp.h>
#include <linux/in.h>
#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/inet_common.h>
#include <net/inet_hashtables.h>
#include <net/tcp_states.h>
#include <net/protocol.h>
#include <net/xfrm.h>

#include "l2tp_core.h"

struct l2tp_ip_sock {
	/* inet_sock has to be the first member of l2tp_ip_sock */
	struct inet_sock	inet;

	__u32			conn_id;
	__u32			peer_conn_id;

	__u64			tx_packets;
	__u64			tx_bytes;
	__u64			tx_errors;
	__u64			rx_packets;
	__u64			rx_bytes;
	__u64			rx_errors;
};

static DEFINE_RWLOCK(l2tp_ip_lock);
static struct hlist_head l2tp_ip_table;
static struct hlist_head l2tp_ip_bind_table;

static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
{
	return (struct l2tp_ip_sock *)sk;
}

static struct sock *__l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
{
	struct hlist_node *node;
	struct sock *sk;

	sk_for_each_bound(sk, node, &l2tp_ip_bind_table) {
		struct inet_sock *inet = inet_sk(sk);
		struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);

		if (l2tp == NULL)
			continue;

		if ((l2tp->conn_id == tunnel_id) &&
		    net_eq(sock_net(sk), net) &&
		    !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
		    !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
			goto found;
	}

	sk = NULL;
found:
	return sk;
}

static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
{
	struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
	if (sk)
		sock_hold(sk);

	return sk;
}

/* When processing receive frames, there are two cases to
 * consider. Data frames consist of a non-zero session-id and an
 * optional cookie. Control frames consist of a regular L2TP header
 * preceded by 32-bits of zeros.
 *
 * L2TPv3 Session Header Over IP
 *
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                           Session ID                          |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |               Cookie (optional, maximum 64 bits)...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *                                                                 |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * L2TPv3 Control Message Header Over IP
 *
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                      (32 bits of zeros)                       |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                     Control Connection ID                     |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |               Ns              |               Nr              |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * All control frames are passed to userspace.
 */
static int l2tp_ip_recv(struct sk_buff *skb)
{
	struct sock *sk;
	u32 session_id;
	u32 tunnel_id;
	unsigned char *ptr, *optr;
	struct l2tp_session *session;
	struct l2tp_tunnel *tunnel = NULL;
	int length;
	int offset;

	/* Point to L2TP header */
	optr = ptr = skb->data;

	if (!pskb_may_pull(skb, 4))
		goto discard;

	session_id = ntohl(*((__be32 *) ptr));
	ptr += 4;

	/* RFC3931: L2TP/IP packets have the first 4 bytes containing
	 * the session_id. If it is 0, the packet is a L2TP control
	 * frame and the session_id value can be discarded.
	 */
	if (session_id == 0) {
		__skb_pull(skb, 4);
		goto pass_up;
	}

	/* Ok, this is a data packet. Lookup the session. */
	session = l2tp_session_find(&init_net, NULL, session_id);
	if (session == NULL)
		goto discard;

	tunnel = session->tunnel;
	if (tunnel == NULL)
		goto discard;

	/* Trace packet contents, if enabled */
	if (tunnel->debug & L2TP_MSG_DATA) {
		length = min(32u, skb->len);
		if (!pskb_may_pull(skb, length))
			goto discard;

		printk(KERN_DEBUG "%s: ip recv: ", tunnel->name);

		offset = 0;
		do {
			printk(" %02X", ptr[offset]);
		} while (++offset < length);

		printk("\n");
	}

	l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);

	return 0;

pass_up:
	/* Get the tunnel_id from the L2TP header */
	if (!pskb_may_pull(skb, 12))
		goto discard;

	if ((skb->data[0] & 0xc0) != 0xc0)
		goto discard;

	tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
	tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
	if (tunnel != NULL)
		sk = tunnel->sock;
	else {
		struct iphdr *iph = (struct iphdr *) skb_network_header(skb);

		read_lock_bh(&l2tp_ip_lock);
		sk = __l2tp_ip_bind_lookup(&init_net, iph->daddr, 0, tunnel_id);
		read_unlock_bh(&l2tp_ip_lock);
	}

	if (sk == NULL)
		goto discard;

	sock_hold(sk);

	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto discard_put;

	nf_reset(skb);

	return sk_receive_skb(sk, skb, 1);

discard_put:
	sock_put(sk);

discard:
	kfree_skb(skb);
	return 0;
}

static int l2tp_ip_open(struct sock *sk)
{
	/* Prevent autobind. We don't have ports. */
	inet_sk(sk)->inet_num = IPPROTO_L2TP;

	write_lock_bh(&l2tp_ip_lock);
	sk_add_node(sk, &l2tp_ip_table);
	write_unlock_bh(&l2tp_ip_lock);

	return 0;
}

static void l2tp_ip_close(struct sock *sk, long timeout)
{
	write_lock_bh(&l2tp_ip_lock);
	hlist_del_init(&sk->sk_bind_node);
	hlist_del_init(&sk->sk_node);
	write_unlock_bh(&l2tp_ip_lock);
	sk_common_release(sk);
}

static void l2tp_ip_destroy_sock(struct sock *sk)
{
	struct sk_buff *skb;

	while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
		kfree_skb(skb);

	sk_refcnt_debug_dec(sk);
}

static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
	int ret = -EINVAL;
	int chk_addr_ret;

	ret = -EADDRINUSE;
	read_lock_bh(&l2tp_ip_lock);
	if (__l2tp_ip_bind_lookup(&init_net, addr->l2tp_addr.s_addr, sk->sk_bound_dev_if, addr->l2tp_conn_id))
		goto out_in_use;

	read_unlock_bh(&l2tp_ip_lock);

	lock_sock(sk);
	if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
		goto out;

	chk_addr_ret = inet_addr_type(&init_net, addr->l2tp_addr.s_addr);
	ret = -EADDRNOTAVAIL;
	if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
	    chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
		goto out;

	inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
	if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
		inet->inet_saddr = 0;  /* Use device */
	sk_dst_reset(sk);

	l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;

	write_lock_bh(&l2tp_ip_lock);
	sk_add_bind_node(sk, &l2tp_ip_bind_table);
	sk_del_node_init(sk);
	write_unlock_bh(&l2tp_ip_lock);
	ret = 0;
out:
	release_sock(sk);

	return ret;

out_in_use:
	read_unlock_bh(&l2tp_ip_lock);

	return ret;
}

static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
	struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
	struct inet_sock *inet = inet_sk(sk);
	struct flowi4 *fl4;
	struct rtable *rt;
	__be32 saddr;
	int oif, rc;

	rc = -EINVAL;
	if (addr_len < sizeof(*lsa))
		goto out;

	rc = -EAFNOSUPPORT;
	if (lsa->l2tp_family != AF_INET)
		goto out;

	lock_sock(sk);

	sk_dst_reset(sk);

	oif = sk->sk_bound_dev_if;
	saddr = inet->inet_saddr;

	rc = -EINVAL;
	if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
		goto out;

	fl4 = &inet->cork.fl.u.ip4;
	rt = ip_route_connect(fl4, lsa->l2tp_addr.s_addr, saddr,
			      RT_CONN_FLAGS(sk), oif,
			      IPPROTO_L2TP,
			      0, 0, sk, true);
	if (IS_ERR(rt)) {
		rc = PTR_ERR(rt);
		if (rc == -ENETUNREACH)
			IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES);
		goto out;
	}

	rc = -ENETUNREACH;
	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
		ip_rt_put(rt);
		goto out;
	}

	l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;

	if (!inet->inet_saddr)
		inet->inet_saddr = fl4->saddr;
	if (!inet->inet_rcv_saddr)
		inet->inet_rcv_saddr = fl4->saddr;
	inet->inet_daddr = fl4->daddr;
	sk->sk_state = TCP_ESTABLISHED;
	inet->inet_id = jiffies;

	sk_dst_set(sk, &rt->dst);

	write_lock_bh(&l2tp_ip_lock);
	hlist_del_init(&sk->sk_bind_node);
	sk_add_bind_node(sk, &l2tp_ip_bind_table);
	write_unlock_bh(&l2tp_ip_lock);

	rc = 0;
out:
	release_sock(sk);
	return rc;
}

static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
			   int *uaddr_len, int peer)
{
	struct sock *sk		= sock->sk;
	struct inet_sock *inet	= inet_sk(sk);
	struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
	struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;

	memset(lsa, 0, sizeof(*lsa));
	lsa->l2tp_family = AF_INET;
	if (peer) {
		if (!inet->inet_dport)
			return -ENOTCONN;
		lsa->l2tp_conn_id = lsk->peer_conn_id;
		lsa->l2tp_addr.s_addr = inet->inet_daddr;
	} else {
		__be32 addr = inet->inet_rcv_saddr;
		if (!addr)
			addr = inet->inet_saddr;
		lsa->l2tp_conn_id = lsk->conn_id;
		lsa->l2tp_addr.s_addr = addr;
	}
	*uaddr_len = sizeof(*lsa);
	return 0;
}

static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
{
	int rc;

	/* Charge it to the socket, dropping if the queue is full. */
	rc = sock_queue_rcv_skb(sk, skb);
	if (rc < 0)
		goto drop;

	return 0;

drop:
	IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
	kfree_skb(skb);
	return -1;
}

/* Userspace will call sendmsg() on the tunnel socket to send L2TP
 * control frames.
 */
static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len)
{
	struct sk_buff *skb;
	int rc;
	struct l2tp_ip_sock *lsa = l2tp_ip_sk(sk);
	struct inet_sock *inet = inet_sk(sk);
	struct rtable *rt = NULL;
	struct flowi4 *fl4;
	int connected = 0;
	__be32 daddr;

	lock_sock(sk);

	rc = -ENOTCONN;
	if (sock_flag(sk, SOCK_DEAD))
		goto out;

	/* Get and verify the address. */
	if (msg->msg_name) {
		struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name;
		rc = -EINVAL;
		if (msg->msg_namelen < sizeof(*lip))
			goto out;

		if (lip->l2tp_family != AF_INET) {
			rc = -EAFNOSUPPORT;
			if (lip->l2tp_family != AF_UNSPEC)
				goto out;
		}

		daddr = lip->l2tp_addr.s_addr;
	} else {
		if (sk->sk_state != TCP_ESTABLISHED)
			return -EDESTADDRREQ;

		daddr = inet->inet_daddr;
		connected = 1;
	}

	/* Allocate a socket buffer */
	rc = -ENOMEM;
	skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
			   4 + len, 0, GFP_KERNEL);
	if (!skb)
		goto error;

	/* Reserve space for headers, putting IP header on 4-byte boundary. */
	skb_reserve(skb, 2 + NET_SKB_PAD);
	skb_reset_network_header(skb);
	skb_reserve(skb, sizeof(struct iphdr));
	skb_reset_transport_header(skb);

	/* Insert 0 session_id */
	*((__be32 *) skb_put(skb, 4)) = 0;

	/* Copy user data into skb */
	rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
	if (rc < 0) {
		kfree_skb(skb);
		goto error;
	}

	fl4 = &inet->cork.fl.u.ip4;
	if (connected)
		rt = (struct rtable *) __sk_dst_check(sk, 0);

	rcu_read_lock();
	if (rt == NULL) {
		const struct ip_options_rcu *inet_opt;

		inet_opt = rcu_dereference(inet->inet_opt);

		/* Use correct destination address if we have options. */
		if (inet_opt && inet_opt->opt.srr)
			daddr = inet_opt->opt.faddr;

		/* If this fails, retransmit mechanism of transport layer will
		 * keep trying until route appears or the connection times
		 * itself out.
		 */
		rt = ip_route_output_ports(sock_net(sk), fl4, sk,
					   daddr, inet->inet_saddr,
					   inet->inet_dport, inet->inet_sport,
					   sk->sk_protocol, RT_CONN_FLAGS(sk),
					   sk->sk_bound_dev_if);
		if (IS_ERR(rt))
			goto no_route;
		if (connected)
			sk_setup_caps(sk, &rt->dst);
		else
			dst_release(&rt->dst); /* safe since we hold rcu_read_lock */
	}

	/* We dont need to clone dst here, it is guaranteed to not disappear.
	 *  __dev_xmit_skb() might force a refcount if needed.
	 */
	skb_dst_set_noref(skb, &rt->dst);

	/* Queue the packet to IP for output */
	rc = ip_queue_xmit(skb, &inet->cork.fl);
	rcu_read_unlock();

error:
	/* Update stats */
	if (rc >= 0) {
		lsa->tx_packets++;
		lsa->tx_bytes += len;
		rc = len;
	} else {
		lsa->tx_errors++;
	}

out:
	release_sock(sk);
	return rc;

no_route:
	rcu_read_unlock();
	IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
	kfree_skb(skb);
	rc = -EHOSTUNREACH;
	goto out;
}

static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
			   size_t len, int noblock, int flags, int *addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
	size_t copied = 0;
	int err = -EOPNOTSUPP;
	struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
	struct sk_buff *skb;

	if (flags & MSG_OOB)
		goto out;

	if (addr_len)
		*addr_len = sizeof(*sin);

	skb = skb_recv_datagram(sk, flags, noblock, &err);
	if (!skb)
		goto out;

	copied = skb->len;
	if (len < copied) {
		msg->msg_flags |= MSG_TRUNC;
		copied = len;
	}

	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
	if (err)
		goto done;

	sock_recv_timestamp(msg, sk, skb);

	/* Copy the address. */
	if (sin) {
		sin->sin_family = AF_INET;
		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
		sin->sin_port = 0;
		memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
	}
	if (inet->cmsg_flags)
		ip_cmsg_recv(msg, skb);
	if (flags & MSG_TRUNC)
		copied = skb->len;
done:
	skb_free_datagram(sk, skb);
out:
	if (err) {
		lsk->rx_errors++;
		return err;
	}

	lsk->rx_packets++;
	lsk->rx_bytes += copied;

	return copied;
}

static struct proto l2tp_ip_prot = {
	.name		   = "L2TP/IP",
	.owner		   = THIS_MODULE,
	.init		   = l2tp_ip_open,
	.close		   = l2tp_ip_close,
	.bind		   = l2tp_ip_bind,
	.connect	   = l2tp_ip_connect,
	.disconnect	   = udp_disconnect,
	.ioctl		   = udp_ioctl,
	.destroy	   = l2tp_ip_destroy_sock,
	.setsockopt	   = ip_setsockopt,
	.getsockopt	   = ip_getsockopt,
	.sendmsg	   = l2tp_ip_sendmsg,
	.recvmsg	   = l2tp_ip_recvmsg,
	.backlog_rcv	   = l2tp_ip_backlog_recv,
	.hash		   = inet_hash,
	.unhash		   = inet_unhash,
	.obj_size	   = sizeof(struct l2tp_ip_sock),
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_ip_setsockopt,
	.compat_getsockopt = compat_ip_getsockopt,
#endif
};

static const struct proto_ops l2tp_ip_ops = {
	.family		   = PF_INET,
	.owner		   = THIS_MODULE,
	.release	   = inet_release,
	.bind		   = inet_bind,
	.connect	   = inet_dgram_connect,
	.socketpair	   = sock_no_socketpair,
	.accept		   = sock_no_accept,
	.getname	   = l2tp_ip_getname,
	.poll		   = datagram_poll,
	.ioctl		   = inet_ioctl,
	.listen		   = sock_no_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,
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_sock_common_setsockopt,
	.compat_getsockopt = compat_sock_common_getsockopt,
#endif
};

static struct inet_protosw l2tp_ip_protosw = {
	.type		= SOCK_DGRAM,
	.protocol	= IPPROTO_L2TP,
	.prot		= &l2tp_ip_prot,
	.ops		= &l2tp_ip_ops,
	.no_check	= 0,
};

static struct net_protocol l2tp_ip_protocol __read_mostly = {
	.handler	= l2tp_ip_recv,
};

static int __init l2tp_ip_init(void)
{
	int err;

	printk(KERN_INFO "L2TP IP encapsulation support (L2TPv3)\n");

	err = proto_register(&l2tp_ip_prot, 1);
	if (err != 0)
		goto out;

	err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
	if (err)
		goto out1;

	inet_register_protosw(&l2tp_ip_protosw);
	return 0;

out1:
	proto_unregister(&l2tp_ip_prot);
out:
	return err;
}

static void __exit l2tp_ip_exit(void)
{
	inet_unregister_protosw(&l2tp_ip_protosw);
	inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
	proto_unregister(&l2tp_ip_prot);
}

module_init(l2tp_ip_init);
module_exit(l2tp_ip_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
MODULE_DESCRIPTION("L2TP over IP");
MODULE_VERSION("1.0");

/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 * enums
 */
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);