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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* L2TPv3 IP encapsulation support
3 *
4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <asm/ioctls.h>
10#include <linux/icmp.h>
11#include <linux/module.h>
12#include <linux/skbuff.h>
13#include <linux/random.h>
14#include <linux/socket.h>
15#include <linux/l2tp.h>
16#include <linux/in.h>
17#include <net/sock.h>
18#include <net/ip.h>
19#include <net/icmp.h>
20#include <net/udp.h>
21#include <net/inet_common.h>
22#include <net/tcp_states.h>
23#include <net/protocol.h>
24#include <net/xfrm.h>
25#include <net/net_namespace.h>
26#include <net/netns/generic.h>
27
28#include "l2tp_core.h"
29
30/* per-net private data for this module */
31static unsigned int l2tp_ip_net_id;
32struct l2tp_ip_net {
33 rwlock_t l2tp_ip_lock;
34 struct hlist_head l2tp_ip_table;
35 struct hlist_head l2tp_ip_bind_table;
36};
37
38struct l2tp_ip_sock {
39 /* inet_sock has to be the first member of l2tp_ip_sock */
40 struct inet_sock inet;
41
42 u32 conn_id;
43 u32 peer_conn_id;
44};
45
46static struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
47{
48 return (struct l2tp_ip_sock *)sk;
49}
50
51static struct l2tp_ip_net *l2tp_ip_pernet(const struct net *net)
52{
53 return net_generic(net, l2tp_ip_net_id);
54}
55
56static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
57 __be32 raddr, int dif, u32 tunnel_id)
58{
59 struct l2tp_ip_net *pn = l2tp_ip_pernet(net);
60 struct sock *sk;
61
62 sk_for_each_bound(sk, &pn->l2tp_ip_bind_table) {
63 const struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
64 const struct inet_sock *inet = inet_sk(sk);
65 int bound_dev_if;
66
67 if (!net_eq(sock_net(sk), net))
68 continue;
69
70 bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
71 if (bound_dev_if && dif && bound_dev_if != dif)
72 continue;
73
74 if (inet->inet_rcv_saddr && laddr &&
75 inet->inet_rcv_saddr != laddr)
76 continue;
77
78 if (inet->inet_daddr && raddr && inet->inet_daddr != raddr)
79 continue;
80
81 if (l2tp->conn_id != tunnel_id)
82 continue;
83
84 goto found;
85 }
86
87 sk = NULL;
88found:
89 return sk;
90}
91
92/* When processing receive frames, there are two cases to
93 * consider. Data frames consist of a non-zero session-id and an
94 * optional cookie. Control frames consist of a regular L2TP header
95 * preceded by 32-bits of zeros.
96 *
97 * L2TPv3 Session Header Over IP
98 *
99 * 0 1 2 3
100 * 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
101 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
102 * | Session ID |
103 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
104 * | Cookie (optional, maximum 64 bits)...
105 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
106 * |
107 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
108 *
109 * L2TPv3 Control Message Header Over IP
110 *
111 * 0 1 2 3
112 * 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
113 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
114 * | (32 bits of zeros) |
115 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
116 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
117 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
118 * | Control Connection ID |
119 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
120 * | Ns | Nr |
121 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
122 *
123 * All control frames are passed to userspace.
124 */
125static int l2tp_ip_recv(struct sk_buff *skb)
126{
127 struct net *net = dev_net(skb->dev);
128 struct l2tp_ip_net *pn;
129 struct sock *sk;
130 u32 session_id;
131 u32 tunnel_id;
132 unsigned char *ptr, *optr;
133 struct l2tp_session *session;
134 struct l2tp_tunnel *tunnel = NULL;
135 struct iphdr *iph;
136
137 pn = l2tp_ip_pernet(net);
138
139 if (!pskb_may_pull(skb, 4))
140 goto discard;
141
142 /* Point to L2TP header */
143 optr = skb->data;
144 ptr = skb->data;
145 session_id = ntohl(*((__be32 *)ptr));
146 ptr += 4;
147
148 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
149 * the session_id. If it is 0, the packet is a L2TP control
150 * frame and the session_id value can be discarded.
151 */
152 if (session_id == 0) {
153 __skb_pull(skb, 4);
154 goto pass_up;
155 }
156
157 /* Ok, this is a data packet. Lookup the session. */
158 session = l2tp_v3_session_get(net, NULL, session_id);
159 if (!session)
160 goto discard;
161
162 tunnel = session->tunnel;
163 if (!tunnel)
164 goto discard_sess;
165
166 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
167 goto discard_sess;
168
169 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
170 l2tp_session_put(session);
171
172 return 0;
173
174pass_up:
175 /* Get the tunnel_id from the L2TP header */
176 if (!pskb_may_pull(skb, 12))
177 goto discard;
178
179 if ((skb->data[0] & 0xc0) != 0xc0)
180 goto discard;
181
182 tunnel_id = ntohl(*(__be32 *)&skb->data[4]);
183 iph = (struct iphdr *)skb_network_header(skb);
184
185 read_lock_bh(&pn->l2tp_ip_lock);
186 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb),
187 tunnel_id);
188 if (!sk) {
189 read_unlock_bh(&pn->l2tp_ip_lock);
190 goto discard;
191 }
192 sock_hold(sk);
193 read_unlock_bh(&pn->l2tp_ip_lock);
194
195 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
196 goto discard_put;
197
198 nf_reset_ct(skb);
199
200 return sk_receive_skb(sk, skb, 1);
201
202discard_sess:
203 l2tp_session_put(session);
204 goto discard;
205
206discard_put:
207 sock_put(sk);
208
209discard:
210 kfree_skb(skb);
211 return 0;
212}
213
214static int l2tp_ip_hash(struct sock *sk)
215{
216 struct l2tp_ip_net *pn = l2tp_ip_pernet(sock_net(sk));
217
218 if (sk_unhashed(sk)) {
219 write_lock_bh(&pn->l2tp_ip_lock);
220 sk_add_node(sk, &pn->l2tp_ip_table);
221 write_unlock_bh(&pn->l2tp_ip_lock);
222 }
223 return 0;
224}
225
226static void l2tp_ip_unhash(struct sock *sk)
227{
228 struct l2tp_ip_net *pn = l2tp_ip_pernet(sock_net(sk));
229
230 if (sk_unhashed(sk))
231 return;
232 write_lock_bh(&pn->l2tp_ip_lock);
233 sk_del_node_init(sk);
234 write_unlock_bh(&pn->l2tp_ip_lock);
235}
236
237static int l2tp_ip_open(struct sock *sk)
238{
239 /* Prevent autobind. We don't have ports. */
240 inet_sk(sk)->inet_num = IPPROTO_L2TP;
241
242 l2tp_ip_hash(sk);
243 return 0;
244}
245
246static void l2tp_ip_close(struct sock *sk, long timeout)
247{
248 struct l2tp_ip_net *pn = l2tp_ip_pernet(sock_net(sk));
249
250 write_lock_bh(&pn->l2tp_ip_lock);
251 hlist_del_init(&sk->sk_bind_node);
252 sk_del_node_init(sk);
253 write_unlock_bh(&pn->l2tp_ip_lock);
254 sk_common_release(sk);
255}
256
257static void l2tp_ip_destroy_sock(struct sock *sk)
258{
259 struct l2tp_tunnel *tunnel;
260
261 __skb_queue_purge(&sk->sk_write_queue);
262
263 tunnel = l2tp_sk_to_tunnel(sk);
264 if (tunnel) {
265 l2tp_tunnel_delete(tunnel);
266 l2tp_tunnel_put(tunnel);
267 }
268}
269
270static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
271{
272 struct inet_sock *inet = inet_sk(sk);
273 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *)uaddr;
274 struct net *net = sock_net(sk);
275 struct l2tp_ip_net *pn;
276 int ret;
277 int chk_addr_ret;
278
279 if (addr_len < sizeof(struct sockaddr_l2tpip))
280 return -EINVAL;
281 if (addr->l2tp_family != AF_INET)
282 return -EINVAL;
283
284 lock_sock(sk);
285
286 ret = -EINVAL;
287 if (!sock_flag(sk, SOCK_ZAPPED))
288 goto out;
289
290 if (sk->sk_state != TCP_CLOSE)
291 goto out;
292
293 chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
294 ret = -EADDRNOTAVAIL;
295 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
296 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
297 goto out;
298
299 if (addr->l2tp_addr.s_addr) {
300 inet->inet_rcv_saddr = addr->l2tp_addr.s_addr;
301 inet->inet_saddr = addr->l2tp_addr.s_addr;
302 }
303 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
304 inet->inet_saddr = 0; /* Use device */
305
306 pn = l2tp_ip_pernet(net);
307 write_lock_bh(&pn->l2tp_ip_lock);
308 if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
309 sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
310 write_unlock_bh(&pn->l2tp_ip_lock);
311 ret = -EADDRINUSE;
312 goto out;
313 }
314
315 sk_dst_reset(sk);
316 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
317
318 sk_add_bind_node(sk, &pn->l2tp_ip_bind_table);
319 sk_del_node_init(sk);
320 write_unlock_bh(&pn->l2tp_ip_lock);
321
322 ret = 0;
323 sock_reset_flag(sk, SOCK_ZAPPED);
324
325out:
326 release_sock(sk);
327
328 return ret;
329}
330
331static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
332{
333 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
334 struct l2tp_ip_net *pn = l2tp_ip_pernet(sock_net(sk));
335 int rc;
336
337 if (addr_len < sizeof(*lsa))
338 return -EINVAL;
339
340 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
341 return -EINVAL;
342
343 lock_sock(sk);
344
345 /* Must bind first - autobinding does not work */
346 if (sock_flag(sk, SOCK_ZAPPED)) {
347 rc = -EINVAL;
348 goto out_sk;
349 }
350
351 rc = __ip4_datagram_connect(sk, uaddr, addr_len);
352 if (rc < 0)
353 goto out_sk;
354
355 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
356
357 write_lock_bh(&pn->l2tp_ip_lock);
358 hlist_del_init(&sk->sk_bind_node);
359 sk_add_bind_node(sk, &pn->l2tp_ip_bind_table);
360 write_unlock_bh(&pn->l2tp_ip_lock);
361
362out_sk:
363 release_sock(sk);
364
365 return rc;
366}
367
368static int l2tp_ip_disconnect(struct sock *sk, int flags)
369{
370 if (sock_flag(sk, SOCK_ZAPPED))
371 return 0;
372
373 return __udp_disconnect(sk, flags);
374}
375
376static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
377 int peer)
378{
379 struct sock *sk = sock->sk;
380 struct inet_sock *inet = inet_sk(sk);
381 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
382 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
383
384 memset(lsa, 0, sizeof(*lsa));
385 lsa->l2tp_family = AF_INET;
386 if (peer) {
387 if (!inet->inet_dport)
388 return -ENOTCONN;
389 lsa->l2tp_conn_id = lsk->peer_conn_id;
390 lsa->l2tp_addr.s_addr = inet->inet_daddr;
391 } else {
392 __be32 addr = inet->inet_rcv_saddr;
393
394 if (!addr)
395 addr = inet->inet_saddr;
396 lsa->l2tp_conn_id = lsk->conn_id;
397 lsa->l2tp_addr.s_addr = addr;
398 }
399 return sizeof(*lsa);
400}
401
402static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
403{
404 int rc;
405
406 /* Charge it to the socket, dropping if the queue is full. */
407 rc = sock_queue_rcv_skb(sk, skb);
408 if (rc < 0)
409 goto drop;
410
411 return 0;
412
413drop:
414 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
415 kfree_skb(skb);
416 return 0;
417}
418
419/* Userspace will call sendmsg() on the tunnel socket to send L2TP
420 * control frames.
421 */
422static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
423{
424 struct sk_buff *skb;
425 int rc;
426 struct inet_sock *inet = inet_sk(sk);
427 struct rtable *rt = NULL;
428 struct flowi4 *fl4;
429 int connected = 0;
430 __be32 daddr;
431
432 lock_sock(sk);
433
434 rc = -ENOTCONN;
435 if (sock_flag(sk, SOCK_DEAD))
436 goto out;
437
438 /* Get and verify the address. */
439 if (msg->msg_name) {
440 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
441
442 rc = -EINVAL;
443 if (msg->msg_namelen < sizeof(*lip))
444 goto out;
445
446 if (lip->l2tp_family != AF_INET) {
447 rc = -EAFNOSUPPORT;
448 if (lip->l2tp_family != AF_UNSPEC)
449 goto out;
450 }
451
452 daddr = lip->l2tp_addr.s_addr;
453 } else {
454 rc = -EDESTADDRREQ;
455 if (sk->sk_state != TCP_ESTABLISHED)
456 goto out;
457
458 daddr = inet->inet_daddr;
459 connected = 1;
460 }
461
462 /* Allocate a socket buffer */
463 rc = -ENOMEM;
464 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
465 4 + len, 0, GFP_KERNEL);
466 if (!skb)
467 goto error;
468
469 /* Reserve space for headers, putting IP header on 4-byte boundary. */
470 skb_reserve(skb, 2 + NET_SKB_PAD);
471 skb_reset_network_header(skb);
472 skb_reserve(skb, sizeof(struct iphdr));
473 skb_reset_transport_header(skb);
474
475 /* Insert 0 session_id */
476 *((__be32 *)skb_put(skb, 4)) = 0;
477
478 /* Copy user data into skb */
479 rc = memcpy_from_msg(skb_put(skb, len), msg, len);
480 if (rc < 0) {
481 kfree_skb(skb);
482 goto error;
483 }
484
485 fl4 = &inet->cork.fl.u.ip4;
486 if (connected)
487 rt = dst_rtable(__sk_dst_check(sk, 0));
488
489 rcu_read_lock();
490 if (!rt) {
491 const struct ip_options_rcu *inet_opt;
492
493 inet_opt = rcu_dereference(inet->inet_opt);
494
495 /* Use correct destination address if we have options. */
496 if (inet_opt && inet_opt->opt.srr)
497 daddr = inet_opt->opt.faddr;
498
499 /* If this fails, retransmit mechanism of transport layer will
500 * keep trying until route appears or the connection times
501 * itself out.
502 */
503 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
504 daddr, inet->inet_saddr,
505 inet->inet_dport, inet->inet_sport,
506 sk->sk_protocol, ip_sock_rt_tos(sk),
507 sk->sk_bound_dev_if);
508 if (IS_ERR(rt))
509 goto no_route;
510 if (connected) {
511 sk_setup_caps(sk, &rt->dst);
512 } else {
513 skb_dst_set(skb, &rt->dst);
514 goto xmit;
515 }
516 }
517
518 /* We don't need to clone dst here, it is guaranteed to not disappear.
519 * __dev_xmit_skb() might force a refcount if needed.
520 */
521 skb_dst_set_noref(skb, &rt->dst);
522
523xmit:
524 /* Queue the packet to IP for output */
525 rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
526 rcu_read_unlock();
527
528error:
529 if (rc >= 0)
530 rc = len;
531
532out:
533 release_sock(sk);
534 return rc;
535
536no_route:
537 rcu_read_unlock();
538 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
539 kfree_skb(skb);
540 rc = -EHOSTUNREACH;
541 goto out;
542}
543
544static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
545 size_t len, int flags, int *addr_len)
546{
547 struct inet_sock *inet = inet_sk(sk);
548 size_t copied = 0;
549 int err = -EOPNOTSUPP;
550 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
551 struct sk_buff *skb;
552
553 if (flags & MSG_OOB)
554 goto out;
555
556 skb = skb_recv_datagram(sk, flags, &err);
557 if (!skb)
558 goto out;
559
560 copied = skb->len;
561 if (len < copied) {
562 msg->msg_flags |= MSG_TRUNC;
563 copied = len;
564 }
565
566 err = skb_copy_datagram_msg(skb, 0, msg, copied);
567 if (err)
568 goto done;
569
570 sock_recv_timestamp(msg, sk, skb);
571
572 /* Copy the address. */
573 if (sin) {
574 sin->sin_family = AF_INET;
575 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
576 sin->sin_port = 0;
577 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
578 *addr_len = sizeof(*sin);
579 }
580 if (inet_cmsg_flags(inet))
581 ip_cmsg_recv(msg, skb);
582 if (flags & MSG_TRUNC)
583 copied = skb->len;
584done:
585 skb_free_datagram(sk, skb);
586out:
587 return err ? err : copied;
588}
589
590int l2tp_ioctl(struct sock *sk, int cmd, int *karg)
591{
592 struct sk_buff *skb;
593
594 switch (cmd) {
595 case SIOCOUTQ:
596 *karg = sk_wmem_alloc_get(sk);
597 break;
598 case SIOCINQ:
599 spin_lock_bh(&sk->sk_receive_queue.lock);
600 skb = skb_peek(&sk->sk_receive_queue);
601 *karg = skb ? skb->len : 0;
602 spin_unlock_bh(&sk->sk_receive_queue.lock);
603 break;
604
605 default:
606 return -ENOIOCTLCMD;
607 }
608
609 return 0;
610}
611EXPORT_SYMBOL_GPL(l2tp_ioctl);
612
613static struct proto l2tp_ip_prot = {
614 .name = "L2TP/IP",
615 .owner = THIS_MODULE,
616 .init = l2tp_ip_open,
617 .close = l2tp_ip_close,
618 .bind = l2tp_ip_bind,
619 .connect = l2tp_ip_connect,
620 .disconnect = l2tp_ip_disconnect,
621 .ioctl = l2tp_ioctl,
622 .destroy = l2tp_ip_destroy_sock,
623 .setsockopt = ip_setsockopt,
624 .getsockopt = ip_getsockopt,
625 .sendmsg = l2tp_ip_sendmsg,
626 .recvmsg = l2tp_ip_recvmsg,
627 .backlog_rcv = l2tp_ip_backlog_recv,
628 .hash = l2tp_ip_hash,
629 .unhash = l2tp_ip_unhash,
630 .obj_size = sizeof(struct l2tp_ip_sock),
631};
632
633static const struct proto_ops l2tp_ip_ops = {
634 .family = PF_INET,
635 .owner = THIS_MODULE,
636 .release = inet_release,
637 .bind = inet_bind,
638 .connect = inet_dgram_connect,
639 .socketpair = sock_no_socketpair,
640 .accept = sock_no_accept,
641 .getname = l2tp_ip_getname,
642 .poll = datagram_poll,
643 .ioctl = inet_ioctl,
644 .gettstamp = sock_gettstamp,
645 .listen = sock_no_listen,
646 .shutdown = inet_shutdown,
647 .setsockopt = sock_common_setsockopt,
648 .getsockopt = sock_common_getsockopt,
649 .sendmsg = inet_sendmsg,
650 .recvmsg = sock_common_recvmsg,
651 .mmap = sock_no_mmap,
652};
653
654static struct inet_protosw l2tp_ip_protosw = {
655 .type = SOCK_DGRAM,
656 .protocol = IPPROTO_L2TP,
657 .prot = &l2tp_ip_prot,
658 .ops = &l2tp_ip_ops,
659};
660
661static struct net_protocol l2tp_ip_protocol __read_mostly = {
662 .handler = l2tp_ip_recv,
663};
664
665static __net_init int l2tp_ip_init_net(struct net *net)
666{
667 struct l2tp_ip_net *pn = net_generic(net, l2tp_ip_net_id);
668
669 rwlock_init(&pn->l2tp_ip_lock);
670 INIT_HLIST_HEAD(&pn->l2tp_ip_table);
671 INIT_HLIST_HEAD(&pn->l2tp_ip_bind_table);
672 return 0;
673}
674
675static __net_exit void l2tp_ip_exit_net(struct net *net)
676{
677 struct l2tp_ip_net *pn = l2tp_ip_pernet(net);
678
679 write_lock_bh(&pn->l2tp_ip_lock);
680 WARN_ON_ONCE(hlist_count_nodes(&pn->l2tp_ip_table) != 0);
681 WARN_ON_ONCE(hlist_count_nodes(&pn->l2tp_ip_bind_table) != 0);
682 write_unlock_bh(&pn->l2tp_ip_lock);
683}
684
685static struct pernet_operations l2tp_ip_net_ops = {
686 .init = l2tp_ip_init_net,
687 .exit = l2tp_ip_exit_net,
688 .id = &l2tp_ip_net_id,
689 .size = sizeof(struct l2tp_ip_net),
690};
691
692static int __init l2tp_ip_init(void)
693{
694 int err;
695
696 pr_info("L2TP IP encapsulation support (L2TPv3)\n");
697
698 err = register_pernet_device(&l2tp_ip_net_ops);
699 if (err)
700 goto out;
701
702 err = proto_register(&l2tp_ip_prot, 1);
703 if (err != 0)
704 goto out1;
705
706 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
707 if (err)
708 goto out2;
709
710 inet_register_protosw(&l2tp_ip_protosw);
711 return 0;
712
713out2:
714 proto_unregister(&l2tp_ip_prot);
715out1:
716 unregister_pernet_device(&l2tp_ip_net_ops);
717out:
718 return err;
719}
720
721static void __exit l2tp_ip_exit(void)
722{
723 inet_unregister_protosw(&l2tp_ip_protosw);
724 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
725 proto_unregister(&l2tp_ip_prot);
726 unregister_pernet_device(&l2tp_ip_net_ops);
727}
728
729module_init(l2tp_ip_init);
730module_exit(l2tp_ip_exit);
731
732MODULE_LICENSE("GPL");
733MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
734MODULE_DESCRIPTION("L2TP over IP");
735MODULE_VERSION("1.0");
736
737/* Use the values of SOCK_DGRAM (2) as type and IPPROTO_L2TP (115) as protocol,
738 * because __stringify doesn't like enums
739 */
740MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 115, 2);
741MODULE_ALIAS_NET_PF_PROTO(PF_INET, 115);
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/icmp.h>
15#include <linux/module.h>
16#include <linux/skbuff.h>
17#include <linux/random.h>
18#include <linux/socket.h>
19#include <linux/l2tp.h>
20#include <linux/in.h>
21#include <net/sock.h>
22#include <net/ip.h>
23#include <net/icmp.h>
24#include <net/udp.h>
25#include <net/inet_common.h>
26#include <net/inet_hashtables.h>
27#include <net/tcp_states.h>
28#include <net/protocol.h>
29#include <net/xfrm.h>
30
31#include "l2tp_core.h"
32
33struct l2tp_ip_sock {
34 /* inet_sock has to be the first member of l2tp_ip_sock */
35 struct inet_sock inet;
36
37 u32 conn_id;
38 u32 peer_conn_id;
39};
40
41static DEFINE_RWLOCK(l2tp_ip_lock);
42static struct hlist_head l2tp_ip_table;
43static struct hlist_head l2tp_ip_bind_table;
44
45static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
46{
47 return (struct l2tp_ip_sock *)sk;
48}
49
50static struct sock *__l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
51{
52 struct hlist_node *node;
53 struct sock *sk;
54
55 sk_for_each_bound(sk, node, &l2tp_ip_bind_table) {
56 struct inet_sock *inet = inet_sk(sk);
57 struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
58
59 if (l2tp == NULL)
60 continue;
61
62 if ((l2tp->conn_id == tunnel_id) &&
63 net_eq(sock_net(sk), net) &&
64 !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
65 !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
66 goto found;
67 }
68
69 sk = NULL;
70found:
71 return sk;
72}
73
74static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
75{
76 struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
77 if (sk)
78 sock_hold(sk);
79
80 return sk;
81}
82
83/* When processing receive frames, there are two cases to
84 * consider. Data frames consist of a non-zero session-id and an
85 * optional cookie. Control frames consist of a regular L2TP header
86 * preceded by 32-bits of zeros.
87 *
88 * L2TPv3 Session Header Over IP
89 *
90 * 0 1 2 3
91 * 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
92 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
93 * | Session ID |
94 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
95 * | Cookie (optional, maximum 64 bits)...
96 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
97 * |
98 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
99 *
100 * L2TPv3 Control Message Header Over IP
101 *
102 * 0 1 2 3
103 * 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
104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
105 * | (32 bits of zeros) |
106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
107 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
109 * | Control Connection ID |
110 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
111 * | Ns | Nr |
112 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
113 *
114 * All control frames are passed to userspace.
115 */
116static int l2tp_ip_recv(struct sk_buff *skb)
117{
118 struct sock *sk;
119 u32 session_id;
120 u32 tunnel_id;
121 unsigned char *ptr, *optr;
122 struct l2tp_session *session;
123 struct l2tp_tunnel *tunnel = NULL;
124 int length;
125
126 /* Point to L2TP header */
127 optr = ptr = skb->data;
128
129 if (!pskb_may_pull(skb, 4))
130 goto discard;
131
132 session_id = ntohl(*((__be32 *) ptr));
133 ptr += 4;
134
135 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
136 * the session_id. If it is 0, the packet is a L2TP control
137 * frame and the session_id value can be discarded.
138 */
139 if (session_id == 0) {
140 __skb_pull(skb, 4);
141 goto pass_up;
142 }
143
144 /* Ok, this is a data packet. Lookup the session. */
145 session = l2tp_session_find(&init_net, NULL, session_id);
146 if (session == NULL)
147 goto discard;
148
149 tunnel = session->tunnel;
150 if (tunnel == NULL)
151 goto discard;
152
153 /* Trace packet contents, if enabled */
154 if (tunnel->debug & L2TP_MSG_DATA) {
155 length = min(32u, skb->len);
156 if (!pskb_may_pull(skb, length))
157 goto discard;
158
159 pr_debug("%s: ip recv\n", tunnel->name);
160 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
161 }
162
163 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
164
165 return 0;
166
167pass_up:
168 /* Get the tunnel_id from the L2TP header */
169 if (!pskb_may_pull(skb, 12))
170 goto discard;
171
172 if ((skb->data[0] & 0xc0) != 0xc0)
173 goto discard;
174
175 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
176 tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
177 if (tunnel != NULL)
178 sk = tunnel->sock;
179 else {
180 struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
181
182 read_lock_bh(&l2tp_ip_lock);
183 sk = __l2tp_ip_bind_lookup(&init_net, iph->daddr, 0, tunnel_id);
184 read_unlock_bh(&l2tp_ip_lock);
185 }
186
187 if (sk == NULL)
188 goto discard;
189
190 sock_hold(sk);
191
192 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
193 goto discard_put;
194
195 nf_reset(skb);
196
197 return sk_receive_skb(sk, skb, 1);
198
199discard_put:
200 sock_put(sk);
201
202discard:
203 kfree_skb(skb);
204 return 0;
205}
206
207static int l2tp_ip_open(struct sock *sk)
208{
209 /* Prevent autobind. We don't have ports. */
210 inet_sk(sk)->inet_num = IPPROTO_L2TP;
211
212 write_lock_bh(&l2tp_ip_lock);
213 sk_add_node(sk, &l2tp_ip_table);
214 write_unlock_bh(&l2tp_ip_lock);
215
216 return 0;
217}
218
219static void l2tp_ip_close(struct sock *sk, long timeout)
220{
221 write_lock_bh(&l2tp_ip_lock);
222 hlist_del_init(&sk->sk_bind_node);
223 sk_del_node_init(sk);
224 write_unlock_bh(&l2tp_ip_lock);
225 sk_common_release(sk);
226}
227
228static void l2tp_ip_destroy_sock(struct sock *sk)
229{
230 struct sk_buff *skb;
231
232 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
233 kfree_skb(skb);
234
235 sk_refcnt_debug_dec(sk);
236}
237
238static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
239{
240 struct inet_sock *inet = inet_sk(sk);
241 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
242 int ret;
243 int chk_addr_ret;
244
245 if (!sock_flag(sk, SOCK_ZAPPED))
246 return -EINVAL;
247 if (addr_len < sizeof(struct sockaddr_l2tpip))
248 return -EINVAL;
249 if (addr->l2tp_family != AF_INET)
250 return -EINVAL;
251
252 ret = -EADDRINUSE;
253 read_lock_bh(&l2tp_ip_lock);
254 if (__l2tp_ip_bind_lookup(&init_net, addr->l2tp_addr.s_addr, sk->sk_bound_dev_if, addr->l2tp_conn_id))
255 goto out_in_use;
256
257 read_unlock_bh(&l2tp_ip_lock);
258
259 lock_sock(sk);
260 if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
261 goto out;
262
263 chk_addr_ret = inet_addr_type(&init_net, addr->l2tp_addr.s_addr);
264 ret = -EADDRNOTAVAIL;
265 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
266 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
267 goto out;
268
269 if (addr->l2tp_addr.s_addr)
270 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
271 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
272 inet->inet_saddr = 0; /* Use device */
273 sk_dst_reset(sk);
274
275 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
276
277 write_lock_bh(&l2tp_ip_lock);
278 sk_add_bind_node(sk, &l2tp_ip_bind_table);
279 sk_del_node_init(sk);
280 write_unlock_bh(&l2tp_ip_lock);
281 ret = 0;
282 sock_reset_flag(sk, SOCK_ZAPPED);
283
284out:
285 release_sock(sk);
286
287 return ret;
288
289out_in_use:
290 read_unlock_bh(&l2tp_ip_lock);
291
292 return ret;
293}
294
295static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
296{
297 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
298 int rc;
299
300 if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
301 return -EINVAL;
302
303 if (addr_len < sizeof(*lsa))
304 return -EINVAL;
305
306 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
307 return -EINVAL;
308
309 rc = ip4_datagram_connect(sk, uaddr, addr_len);
310 if (rc < 0)
311 return rc;
312
313 lock_sock(sk);
314
315 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
316
317 write_lock_bh(&l2tp_ip_lock);
318 hlist_del_init(&sk->sk_bind_node);
319 sk_add_bind_node(sk, &l2tp_ip_bind_table);
320 write_unlock_bh(&l2tp_ip_lock);
321
322 release_sock(sk);
323 return rc;
324}
325
326static int l2tp_ip_disconnect(struct sock *sk, int flags)
327{
328 if (sock_flag(sk, SOCK_ZAPPED))
329 return 0;
330
331 return udp_disconnect(sk, flags);
332}
333
334static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
335 int *uaddr_len, int peer)
336{
337 struct sock *sk = sock->sk;
338 struct inet_sock *inet = inet_sk(sk);
339 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
340 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
341
342 memset(lsa, 0, sizeof(*lsa));
343 lsa->l2tp_family = AF_INET;
344 if (peer) {
345 if (!inet->inet_dport)
346 return -ENOTCONN;
347 lsa->l2tp_conn_id = lsk->peer_conn_id;
348 lsa->l2tp_addr.s_addr = inet->inet_daddr;
349 } else {
350 __be32 addr = inet->inet_rcv_saddr;
351 if (!addr)
352 addr = inet->inet_saddr;
353 lsa->l2tp_conn_id = lsk->conn_id;
354 lsa->l2tp_addr.s_addr = addr;
355 }
356 *uaddr_len = sizeof(*lsa);
357 return 0;
358}
359
360static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
361{
362 int rc;
363
364 /* Charge it to the socket, dropping if the queue is full. */
365 rc = sock_queue_rcv_skb(sk, skb);
366 if (rc < 0)
367 goto drop;
368
369 return 0;
370
371drop:
372 IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
373 kfree_skb(skb);
374 return -1;
375}
376
377/* Userspace will call sendmsg() on the tunnel socket to send L2TP
378 * control frames.
379 */
380static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len)
381{
382 struct sk_buff *skb;
383 int rc;
384 struct inet_sock *inet = inet_sk(sk);
385 struct rtable *rt = NULL;
386 struct flowi4 *fl4;
387 int connected = 0;
388 __be32 daddr;
389
390 lock_sock(sk);
391
392 rc = -ENOTCONN;
393 if (sock_flag(sk, SOCK_DEAD))
394 goto out;
395
396 /* Get and verify the address. */
397 if (msg->msg_name) {
398 struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name;
399 rc = -EINVAL;
400 if (msg->msg_namelen < sizeof(*lip))
401 goto out;
402
403 if (lip->l2tp_family != AF_INET) {
404 rc = -EAFNOSUPPORT;
405 if (lip->l2tp_family != AF_UNSPEC)
406 goto out;
407 }
408
409 daddr = lip->l2tp_addr.s_addr;
410 } else {
411 rc = -EDESTADDRREQ;
412 if (sk->sk_state != TCP_ESTABLISHED)
413 goto out;
414
415 daddr = inet->inet_daddr;
416 connected = 1;
417 }
418
419 /* Allocate a socket buffer */
420 rc = -ENOMEM;
421 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
422 4 + len, 0, GFP_KERNEL);
423 if (!skb)
424 goto error;
425
426 /* Reserve space for headers, putting IP header on 4-byte boundary. */
427 skb_reserve(skb, 2 + NET_SKB_PAD);
428 skb_reset_network_header(skb);
429 skb_reserve(skb, sizeof(struct iphdr));
430 skb_reset_transport_header(skb);
431
432 /* Insert 0 session_id */
433 *((__be32 *) skb_put(skb, 4)) = 0;
434
435 /* Copy user data into skb */
436 rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
437 if (rc < 0) {
438 kfree_skb(skb);
439 goto error;
440 }
441
442 fl4 = &inet->cork.fl.u.ip4;
443 if (connected)
444 rt = (struct rtable *) __sk_dst_check(sk, 0);
445
446 rcu_read_lock();
447 if (rt == NULL) {
448 const struct ip_options_rcu *inet_opt;
449
450 inet_opt = rcu_dereference(inet->inet_opt);
451
452 /* Use correct destination address if we have options. */
453 if (inet_opt && inet_opt->opt.srr)
454 daddr = inet_opt->opt.faddr;
455
456 /* If this fails, retransmit mechanism of transport layer will
457 * keep trying until route appears or the connection times
458 * itself out.
459 */
460 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
461 daddr, inet->inet_saddr,
462 inet->inet_dport, inet->inet_sport,
463 sk->sk_protocol, RT_CONN_FLAGS(sk),
464 sk->sk_bound_dev_if);
465 if (IS_ERR(rt))
466 goto no_route;
467 if (connected) {
468 sk_setup_caps(sk, &rt->dst);
469 } else {
470 skb_dst_set(skb, &rt->dst);
471 goto xmit;
472 }
473 }
474
475 /* We dont need to clone dst here, it is guaranteed to not disappear.
476 * __dev_xmit_skb() might force a refcount if needed.
477 */
478 skb_dst_set_noref(skb, &rt->dst);
479
480xmit:
481 /* Queue the packet to IP for output */
482 rc = ip_queue_xmit(skb, &inet->cork.fl);
483 rcu_read_unlock();
484
485error:
486 if (rc >= 0)
487 rc = len;
488
489out:
490 release_sock(sk);
491 return rc;
492
493no_route:
494 rcu_read_unlock();
495 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
496 kfree_skb(skb);
497 rc = -EHOSTUNREACH;
498 goto out;
499}
500
501static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
502 size_t len, int noblock, int flags, int *addr_len)
503{
504 struct inet_sock *inet = inet_sk(sk);
505 size_t copied = 0;
506 int err = -EOPNOTSUPP;
507 struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
508 struct sk_buff *skb;
509
510 if (flags & MSG_OOB)
511 goto out;
512
513 if (addr_len)
514 *addr_len = sizeof(*sin);
515
516 skb = skb_recv_datagram(sk, flags, noblock, &err);
517 if (!skb)
518 goto out;
519
520 copied = skb->len;
521 if (len < copied) {
522 msg->msg_flags |= MSG_TRUNC;
523 copied = len;
524 }
525
526 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
527 if (err)
528 goto done;
529
530 sock_recv_timestamp(msg, sk, skb);
531
532 /* Copy the address. */
533 if (sin) {
534 sin->sin_family = AF_INET;
535 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
536 sin->sin_port = 0;
537 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
538 }
539 if (inet->cmsg_flags)
540 ip_cmsg_recv(msg, skb);
541 if (flags & MSG_TRUNC)
542 copied = skb->len;
543done:
544 skb_free_datagram(sk, skb);
545out:
546 return err ? err : copied;
547}
548
549static struct proto l2tp_ip_prot = {
550 .name = "L2TP/IP",
551 .owner = THIS_MODULE,
552 .init = l2tp_ip_open,
553 .close = l2tp_ip_close,
554 .bind = l2tp_ip_bind,
555 .connect = l2tp_ip_connect,
556 .disconnect = l2tp_ip_disconnect,
557 .ioctl = udp_ioctl,
558 .destroy = l2tp_ip_destroy_sock,
559 .setsockopt = ip_setsockopt,
560 .getsockopt = ip_getsockopt,
561 .sendmsg = l2tp_ip_sendmsg,
562 .recvmsg = l2tp_ip_recvmsg,
563 .backlog_rcv = l2tp_ip_backlog_recv,
564 .hash = inet_hash,
565 .unhash = inet_unhash,
566 .obj_size = sizeof(struct l2tp_ip_sock),
567#ifdef CONFIG_COMPAT
568 .compat_setsockopt = compat_ip_setsockopt,
569 .compat_getsockopt = compat_ip_getsockopt,
570#endif
571};
572
573static const struct proto_ops l2tp_ip_ops = {
574 .family = PF_INET,
575 .owner = THIS_MODULE,
576 .release = inet_release,
577 .bind = inet_bind,
578 .connect = inet_dgram_connect,
579 .socketpair = sock_no_socketpair,
580 .accept = sock_no_accept,
581 .getname = l2tp_ip_getname,
582 .poll = datagram_poll,
583 .ioctl = inet_ioctl,
584 .listen = sock_no_listen,
585 .shutdown = inet_shutdown,
586 .setsockopt = sock_common_setsockopt,
587 .getsockopt = sock_common_getsockopt,
588 .sendmsg = inet_sendmsg,
589 .recvmsg = sock_common_recvmsg,
590 .mmap = sock_no_mmap,
591 .sendpage = sock_no_sendpage,
592#ifdef CONFIG_COMPAT
593 .compat_setsockopt = compat_sock_common_setsockopt,
594 .compat_getsockopt = compat_sock_common_getsockopt,
595#endif
596};
597
598static struct inet_protosw l2tp_ip_protosw = {
599 .type = SOCK_DGRAM,
600 .protocol = IPPROTO_L2TP,
601 .prot = &l2tp_ip_prot,
602 .ops = &l2tp_ip_ops,
603 .no_check = 0,
604};
605
606static struct net_protocol l2tp_ip_protocol __read_mostly = {
607 .handler = l2tp_ip_recv,
608};
609
610static int __init l2tp_ip_init(void)
611{
612 int err;
613
614 pr_info("L2TP IP encapsulation support (L2TPv3)\n");
615
616 err = proto_register(&l2tp_ip_prot, 1);
617 if (err != 0)
618 goto out;
619
620 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
621 if (err)
622 goto out1;
623
624 inet_register_protosw(&l2tp_ip_protosw);
625 return 0;
626
627out1:
628 proto_unregister(&l2tp_ip_prot);
629out:
630 return err;
631}
632
633static void __exit l2tp_ip_exit(void)
634{
635 inet_unregister_protosw(&l2tp_ip_protosw);
636 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
637 proto_unregister(&l2tp_ip_prot);
638}
639
640module_init(l2tp_ip_init);
641module_exit(l2tp_ip_exit);
642
643MODULE_LICENSE("GPL");
644MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
645MODULE_DESCRIPTION("L2TP over IP");
646MODULE_VERSION("1.0");
647
648/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
649 * enums
650 */
651MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);