1/*
2 * L2TPv3 IP encapsulation support
3 *
4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
5 *
6 *	This program is free software; you can redistribute it and/or
7 *	modify it under the terms of the GNU General Public License
8 *	as published by the Free Software Foundation; either version
9 *	2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/icmp.h>
13#include <linux/module.h>
14#include <linux/skbuff.h>
15#include <linux/random.h>
16#include <linux/socket.h>
17#include <linux/l2tp.h>
18#include <linux/in.h>
19#include <net/sock.h>
20#include <net/ip.h>
21#include <net/icmp.h>
22#include <net/udp.h>
23#include <net/inet_common.h>
24#include <net/inet_hashtables.h>
25#include <net/tcp_states.h>
26#include <net/protocol.h>
27#include <net/xfrm.h>
28
29#include "l2tp_core.h"
30
31struct l2tp_ip_sock {
32	/* inet_sock has to be the first member of l2tp_ip_sock */
33	struct inet_sock	inet;
34
35	__u32			conn_id;
36	__u32			peer_conn_id;
37
38	__u64			tx_packets;
39	__u64			tx_bytes;
40	__u64			tx_errors;
41	__u64			rx_packets;
42	__u64			rx_bytes;
43	__u64			rx_errors;
44};
45
46static DEFINE_RWLOCK(l2tp_ip_lock);
47static struct hlist_head l2tp_ip_table;
48static struct hlist_head l2tp_ip_bind_table;
49
50static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
51{
52	return (struct l2tp_ip_sock *)sk;
53}
54
55static struct sock *__l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
56{
57	struct hlist_node *node;
58	struct sock *sk;
59
60	sk_for_each_bound(sk, node, &l2tp_ip_bind_table) {
61		struct inet_sock *inet = inet_sk(sk);
62		struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
63
64		if (l2tp == NULL)
65			continue;
66
67		if ((l2tp->conn_id == tunnel_id) &&
68#ifdef CONFIG_NET_NS
69		    (sk->sk_net == net) &&
70#endif
71		    !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
72		    !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
73			goto found;
74	}
75
76	sk = NULL;
77found:
78	return sk;
79}
80
81static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
82{
83	struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
84	if (sk)
85		sock_hold(sk);
86
87	return sk;
88}
89
90/* When processing receive frames, there are two cases to
91 * consider. Data frames consist of a non-zero session-id and an
92 * optional cookie. Control frames consist of a regular L2TP header
93 * preceded by 32-bits of zeros.
94 *
95 * L2TPv3 Session Header Over IP
96 *
97 *  0                   1                   2                   3
98 *  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
99 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
100 * |                           Session ID                          |
101 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
102 * |               Cookie (optional, maximum 64 bits)...
103 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
104 *                                                                 |
105 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
106 *
107 * L2TPv3 Control Message Header Over IP
108 *
109 *  0                   1                   2                   3
110 *  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
111 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
112 * |                      (32 bits of zeros)                       |
113 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
114 * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
115 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
116 * |                     Control Connection ID                     |
117 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
118 * |               Ns              |               Nr              |
119 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
120 *
121 * All control frames are passed to userspace.
122 */
123static int l2tp_ip_recv(struct sk_buff *skb)
124{
125	struct sock *sk;
126	u32 session_id;
127	u32 tunnel_id;
128	unsigned char *ptr, *optr;
129	struct l2tp_session *session;
130	struct l2tp_tunnel *tunnel = NULL;
131	int length;
132	int offset;
133
134	/* Point to L2TP header */
135	optr = ptr = skb->data;
136
137	if (!pskb_may_pull(skb, 4))
138		goto discard;
139
140	session_id = ntohl(*((__be32 *) ptr));
141	ptr += 4;
142
143	/* RFC3931: L2TP/IP packets have the first 4 bytes containing
144	 * the session_id. If it is 0, the packet is a L2TP control
145	 * frame and the session_id value can be discarded.
146	 */
147	if (session_id == 0) {
148		__skb_pull(skb, 4);
149		goto pass_up;
150	}
151
152	/* Ok, this is a data packet. Lookup the session. */
153	session = l2tp_session_find(&init_net, NULL, session_id);
154	if (session == NULL)
155		goto discard;
156
157	tunnel = session->tunnel;
158	if (tunnel == NULL)
159		goto discard;
160
161	/* Trace packet contents, if enabled */
162	if (tunnel->debug & L2TP_MSG_DATA) {
163		length = min(32u, skb->len);
164		if (!pskb_may_pull(skb, length))
165			goto discard;
166
167		printk(KERN_DEBUG "%s: ip recv: ", tunnel->name);
168
169		offset = 0;
170		do {
171			printk(" %02X", ptr[offset]);
172		} while (++offset < length);
173
174		printk("\n");
175	}
176
177	l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
178
179	return 0;
180
181pass_up:
182	/* Get the tunnel_id from the L2TP header */
183	if (!pskb_may_pull(skb, 12))
184		goto discard;
185
186	if ((skb->data[0] & 0xc0) != 0xc0)
187		goto discard;
188
189	tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
190	tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
191	if (tunnel != NULL)
192		sk = tunnel->sock;
193	else {
194		struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
195
196		read_lock_bh(&l2tp_ip_lock);
197		sk = __l2tp_ip_bind_lookup(&init_net, iph->daddr, 0, tunnel_id);
198		read_unlock_bh(&l2tp_ip_lock);
199	}
200
201	if (sk == NULL)
202		goto discard;
203
204	sock_hold(sk);
205
206	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
207		goto discard_put;
208
209	nf_reset(skb);
210
211	return sk_receive_skb(sk, skb, 1);
212
213discard_put:
214	sock_put(sk);
215
216discard:
217	kfree_skb(skb);
218	return 0;
219}
220
221static int l2tp_ip_open(struct sock *sk)
222{
223	/* Prevent autobind. We don't have ports. */
224	inet_sk(sk)->inet_num = IPPROTO_L2TP;
225
226	write_lock_bh(&l2tp_ip_lock);
227	sk_add_node(sk, &l2tp_ip_table);
228	write_unlock_bh(&l2tp_ip_lock);
229
230	return 0;
231}
232
233static void l2tp_ip_close(struct sock *sk, long timeout)
234{
235	write_lock_bh(&l2tp_ip_lock);
236	hlist_del_init(&sk->sk_bind_node);
237	hlist_del_init(&sk->sk_node);
238	write_unlock_bh(&l2tp_ip_lock);
239	sk_common_release(sk);
240}
241
242static void l2tp_ip_destroy_sock(struct sock *sk)
243{
244	struct sk_buff *skb;
245
246	while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
247		kfree_skb(skb);
248
249	sk_refcnt_debug_dec(sk);
250}
251
252static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
253{
254	struct inet_sock *inet = inet_sk(sk);
255	struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
256	int ret = -EINVAL;
257	int chk_addr_ret;
258
259	ret = -EADDRINUSE;
260	read_lock_bh(&l2tp_ip_lock);
261	if (__l2tp_ip_bind_lookup(&init_net, addr->l2tp_addr.s_addr, sk->sk_bound_dev_if, addr->l2tp_conn_id))
262		goto out_in_use;
263
264	read_unlock_bh(&l2tp_ip_lock);
265
266	lock_sock(sk);
267	if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
268		goto out;
269
270	chk_addr_ret = inet_addr_type(&init_net, addr->l2tp_addr.s_addr);
271	ret = -EADDRNOTAVAIL;
272	if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
273	    chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
274		goto out;
275
276	inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
277	if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
278		inet->inet_saddr = 0;  /* Use device */
279	sk_dst_reset(sk);
280
281	l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
282
283	write_lock_bh(&l2tp_ip_lock);
284	sk_add_bind_node(sk, &l2tp_ip_bind_table);
285	sk_del_node_init(sk);
286	write_unlock_bh(&l2tp_ip_lock);
287	ret = 0;
288out:
289	release_sock(sk);
290
291	return ret;
292
293out_in_use:
294	read_unlock_bh(&l2tp_ip_lock);
295
296	return ret;
297}
298
299static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
300{
301	int rc;
302	struct inet_sock *inet = inet_sk(sk);
303	struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
304	struct rtable *rt;
305	__be32 saddr;
306	int oif;
307
308	rc = -EINVAL;
309	if (addr_len < sizeof(*lsa))
310		goto out;
311
312	rc = -EAFNOSUPPORT;
313	if (lsa->l2tp_family != AF_INET)
314		goto out;
315
316	sk_dst_reset(sk);
317
318	oif = sk->sk_bound_dev_if;
319	saddr = inet->inet_saddr;
320
321	rc = -EINVAL;
322	if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
323		goto out;
324
325	rc = ip_route_connect(&rt, lsa->l2tp_addr.s_addr, saddr,
326			      RT_CONN_FLAGS(sk), oif,
327			      IPPROTO_L2TP,
328			      0, 0, sk, 1);
329	if (rc) {
330		if (rc == -ENETUNREACH)
331			IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES);
332		goto out;
333	}
334
335	rc = -ENETUNREACH;
336	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
337		ip_rt_put(rt);
338		goto out;
339	}
340
341	l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
342
343	if (!inet->inet_saddr)
344		inet->inet_saddr = rt->rt_src;
345	if (!inet->inet_rcv_saddr)
346		inet->inet_rcv_saddr = rt->rt_src;
347	inet->inet_daddr = rt->rt_dst;
348	sk->sk_state = TCP_ESTABLISHED;
349	inet->inet_id = jiffies;
350
351	sk_dst_set(sk, &rt->dst);
352
353	write_lock_bh(&l2tp_ip_lock);
354	hlist_del_init(&sk->sk_bind_node);
355	sk_add_bind_node(sk, &l2tp_ip_bind_table);
356	write_unlock_bh(&l2tp_ip_lock);
357
358	rc = 0;
359out:
360	return rc;
361}
362
363static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
364			   int *uaddr_len, int peer)
365{
366	struct sock *sk		= sock->sk;
367	struct inet_sock *inet	= inet_sk(sk);
368	struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
369	struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
370
371	memset(lsa, 0, sizeof(*lsa));
372	lsa->l2tp_family = AF_INET;
373	if (peer) {
374		if (!inet->inet_dport)
375			return -ENOTCONN;
376		lsa->l2tp_conn_id = lsk->peer_conn_id;
377		lsa->l2tp_addr.s_addr = inet->inet_daddr;
378	} else {
379		__be32 addr = inet->inet_rcv_saddr;
380		if (!addr)
381			addr = inet->inet_saddr;
382		lsa->l2tp_conn_id = lsk->conn_id;
383		lsa->l2tp_addr.s_addr = addr;
384	}
385	*uaddr_len = sizeof(*lsa);
386	return 0;
387}
388
389static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
390{
391	int rc;
392
393	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
394		goto drop;
395
396	nf_reset(skb);
397
398	/* Charge it to the socket, dropping if the queue is full. */
399	rc = sock_queue_rcv_skb(sk, skb);
400	if (rc < 0)
401		goto drop;
402
403	return 0;
404
405drop:
406	IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
407	kfree_skb(skb);
408	return -1;
409}
410
411/* Userspace will call sendmsg() on the tunnel socket to send L2TP
412 * control frames.
413 */
414static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len)
415{
416	struct sk_buff *skb;
417	int rc;
418	struct l2tp_ip_sock *lsa = l2tp_ip_sk(sk);
419	struct inet_sock *inet = inet_sk(sk);
420	struct ip_options *opt = inet->opt;
421	struct rtable *rt = NULL;
422	int connected = 0;
423	__be32 daddr;
424
425	if (sock_flag(sk, SOCK_DEAD))
426		return -ENOTCONN;
427
428	/* Get and verify the address. */
429	if (msg->msg_name) {
430		struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name;
431		if (msg->msg_namelen < sizeof(*lip))
432			return -EINVAL;
433
434		if (lip->l2tp_family != AF_INET) {
435			if (lip->l2tp_family != AF_UNSPEC)
436				return -EAFNOSUPPORT;
437		}
438
439		daddr = lip->l2tp_addr.s_addr;
440	} else {
441		if (sk->sk_state != TCP_ESTABLISHED)
442			return -EDESTADDRREQ;
443
444		daddr = inet->inet_daddr;
445		connected = 1;
446	}
447
448	/* Allocate a socket buffer */
449	rc = -ENOMEM;
450	skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
451			   4 + len, 0, GFP_KERNEL);
452	if (!skb)
453		goto error;
454
455	/* Reserve space for headers, putting IP header on 4-byte boundary. */
456	skb_reserve(skb, 2 + NET_SKB_PAD);
457	skb_reset_network_header(skb);
458	skb_reserve(skb, sizeof(struct iphdr));
459	skb_reset_transport_header(skb);
460
461	/* Insert 0 session_id */
462	*((__be32 *) skb_put(skb, 4)) = 0;
463
464	/* Copy user data into skb */
465	rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
466	if (rc < 0) {
467		kfree_skb(skb);
468		goto error;
469	}
470
471	if (connected)
472		rt = (struct rtable *) __sk_dst_check(sk, 0);
473
474	if (rt == NULL) {
475		/* Use correct destination address if we have options. */
476		if (opt && opt->srr)
477			daddr = opt->faddr;
478
479		{
480			struct flowi fl = { .oif = sk->sk_bound_dev_if,
481					    .nl_u = { .ip4_u = {
482							.daddr = daddr,
483							.saddr = inet->inet_saddr,
484							.tos = RT_CONN_FLAGS(sk) } },
485					    .proto = sk->sk_protocol,
486					    .flags = inet_sk_flowi_flags(sk),
487					    .uli_u = { .ports = {
488							 .sport = inet->inet_sport,
489							 .dport = inet->inet_dport } } };
490
491			/* If this fails, retransmit mechanism of transport layer will
492			 * keep trying until route appears or the connection times
493			 * itself out.
494			 */
495			security_sk_classify_flow(sk, &fl);
496			if (ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 0))
497				goto no_route;
498		}
499		sk_setup_caps(sk, &rt->dst);
500	}
501	skb_dst_set(skb, dst_clone(&rt->dst));
502
503	/* Queue the packet to IP for output */
504	rc = ip_queue_xmit(skb);
505
506error:
507	/* Update stats */
508	if (rc >= 0) {
509		lsa->tx_packets++;
510		lsa->tx_bytes += len;
511		rc = len;
512	} else {
513		lsa->tx_errors++;
514	}
515
516	return rc;
517
518no_route:
519	IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
520	kfree_skb(skb);
521	return -EHOSTUNREACH;
522}
523
524static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
525			   size_t len, int noblock, int flags, int *addr_len)
526{
527	struct inet_sock *inet = inet_sk(sk);
528	struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
529	size_t copied = 0;
530	int err = -EOPNOTSUPP;
531	struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
532	struct sk_buff *skb;
533
534	if (flags & MSG_OOB)
535		goto out;
536
537	if (addr_len)
538		*addr_len = sizeof(*sin);
539
540	skb = skb_recv_datagram(sk, flags, noblock, &err);
541	if (!skb)
542		goto out;
543
544	copied = skb->len;
545	if (len < copied) {
546		msg->msg_flags |= MSG_TRUNC;
547		copied = len;
548	}
549
550	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
551	if (err)
552		goto done;
553
554	sock_recv_timestamp(msg, sk, skb);
555
556	/* Copy the address. */
557	if (sin) {
558		sin->sin_family = AF_INET;
559		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
560		sin->sin_port = 0;
561		memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
562	}
563	if (inet->cmsg_flags)
564		ip_cmsg_recv(msg, skb);
565	if (flags & MSG_TRUNC)
566		copied = skb->len;
567done:
568	skb_free_datagram(sk, skb);
569out:
570	if (err) {
571		lsk->rx_errors++;
572		return err;
573	}
574
575	lsk->rx_packets++;
576	lsk->rx_bytes += copied;
577
578	return copied;
579}
580
581struct proto l2tp_ip_prot = {
582	.name		   = "L2TP/IP",
583	.owner		   = THIS_MODULE,
584	.init		   = l2tp_ip_open,
585	.close		   = l2tp_ip_close,
586	.bind		   = l2tp_ip_bind,
587	.connect	   = l2tp_ip_connect,
588	.disconnect	   = udp_disconnect,
589	.ioctl		   = udp_ioctl,
590	.destroy	   = l2tp_ip_destroy_sock,
591	.setsockopt	   = ip_setsockopt,
592	.getsockopt	   = ip_getsockopt,
593	.sendmsg	   = l2tp_ip_sendmsg,
594	.recvmsg	   = l2tp_ip_recvmsg,
595	.backlog_rcv	   = l2tp_ip_backlog_recv,
596	.hash		   = inet_hash,
597	.unhash		   = inet_unhash,
598	.obj_size	   = sizeof(struct l2tp_ip_sock),
599#ifdef CONFIG_COMPAT
600	.compat_setsockopt = compat_ip_setsockopt,
601	.compat_getsockopt = compat_ip_getsockopt,
602#endif
603};
604
605static const struct proto_ops l2tp_ip_ops = {
606	.family		   = PF_INET,
607	.owner		   = THIS_MODULE,
608	.release	   = inet_release,
609	.bind		   = inet_bind,
610	.connect	   = inet_dgram_connect,
611	.socketpair	   = sock_no_socketpair,
612	.accept		   = sock_no_accept,
613	.getname	   = l2tp_ip_getname,
614	.poll		   = datagram_poll,
615	.ioctl		   = inet_ioctl,
616	.listen		   = sock_no_listen,
617	.shutdown	   = inet_shutdown,
618	.setsockopt	   = sock_common_setsockopt,
619	.getsockopt	   = sock_common_getsockopt,
620	.sendmsg	   = inet_sendmsg,
621	.recvmsg	   = sock_common_recvmsg,
622	.mmap		   = sock_no_mmap,
623	.sendpage	   = sock_no_sendpage,
624#ifdef CONFIG_COMPAT
625	.compat_setsockopt = compat_sock_common_setsockopt,
626	.compat_getsockopt = compat_sock_common_getsockopt,
627#endif
628};
629
630static struct inet_protosw l2tp_ip_protosw = {
631	.type		= SOCK_DGRAM,
632	.protocol	= IPPROTO_L2TP,
633	.prot		= &l2tp_ip_prot,
634	.ops		= &l2tp_ip_ops,
635	.no_check	= 0,
636};
637
638static struct net_protocol l2tp_ip_protocol __read_mostly = {
639	.handler	= l2tp_ip_recv,
640};
641
642static int __init l2tp_ip_init(void)
643{
644	int err;
645
646	printk(KERN_INFO "L2TP IP encapsulation support (L2TPv3)\n");
647
648	err = proto_register(&l2tp_ip_prot, 1);
649	if (err != 0)
650		goto out;
651
652	err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
653	if (err)
654		goto out1;
655
656	inet_register_protosw(&l2tp_ip_protosw);
657	return 0;
658
659out1:
660	proto_unregister(&l2tp_ip_prot);
661out:
662	return err;
663}
664
665static void __exit l2tp_ip_exit(void)
666{
667	inet_unregister_protosw(&l2tp_ip_protosw);
668	inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
669	proto_unregister(&l2tp_ip_prot);
670}
671
672module_init(l2tp_ip_init);
673module_exit(l2tp_ip_exit);
674
675MODULE_LICENSE("GPL");
676MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
677MODULE_DESCRIPTION("L2TP over IP");
678MODULE_VERSION("1.0");
679
680/* Use the value of SOCK_DGRAM (2) directory, because __stringify does't like
681 * enums
682 */
683MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
684