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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 <asm/ioctls.h>
15#include <linux/icmp.h>
16#include <linux/module.h>
17#include <linux/skbuff.h>
18#include <linux/random.h>
19#include <linux/socket.h>
20#include <linux/l2tp.h>
21#include <linux/in.h>
22#include <net/sock.h>
23#include <net/ip.h>
24#include <net/icmp.h>
25#include <net/udp.h>
26#include <net/inet_common.h>
27#include <net/inet_hashtables.h>
28#include <net/tcp_states.h>
29#include <net/protocol.h>
30#include <net/xfrm.h>
31
32#include "l2tp_core.h"
33
34struct l2tp_ip_sock {
35 /* inet_sock has to be the first member of l2tp_ip_sock */
36 struct inet_sock inet;
37
38 u32 conn_id;
39 u32 peer_conn_id;
40};
41
42static DEFINE_RWLOCK(l2tp_ip_lock);
43static struct hlist_head l2tp_ip_table;
44static struct hlist_head l2tp_ip_bind_table;
45
46static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
47{
48 return (struct l2tp_ip_sock *)sk;
49}
50
51static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
52 __be32 raddr, int dif, u32 tunnel_id)
53{
54 struct sock *sk;
55
56 sk_for_each_bound(sk, &l2tp_ip_bind_table) {
57 const struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
58 const struct inet_sock *inet = inet_sk(sk);
59
60 if (!net_eq(sock_net(sk), net))
61 continue;
62
63 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
64 continue;
65
66 if (inet->inet_rcv_saddr && laddr &&
67 inet->inet_rcv_saddr != laddr)
68 continue;
69
70 if (inet->inet_daddr && raddr && inet->inet_daddr != raddr)
71 continue;
72
73 if (l2tp->conn_id != tunnel_id)
74 continue;
75
76 goto found;
77 }
78
79 sk = NULL;
80found:
81 return sk;
82}
83
84/* When processing receive frames, there are two cases to
85 * consider. Data frames consist of a non-zero session-id and an
86 * optional cookie. Control frames consist of a regular L2TP header
87 * preceded by 32-bits of zeros.
88 *
89 * L2TPv3 Session Header Over IP
90 *
91 * 0 1 2 3
92 * 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
93 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
94 * | Session ID |
95 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
96 * | Cookie (optional, maximum 64 bits)...
97 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
98 * |
99 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
100 *
101 * L2TPv3 Control Message Header Over IP
102 *
103 * 0 1 2 3
104 * 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
105 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
106 * | (32 bits of zeros) |
107 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
108 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
109 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
110 * | Control Connection ID |
111 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
112 * | Ns | Nr |
113 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
114 *
115 * All control frames are passed to userspace.
116 */
117static int l2tp_ip_recv(struct sk_buff *skb)
118{
119 struct net *net = dev_net(skb->dev);
120 struct sock *sk;
121 u32 session_id;
122 u32 tunnel_id;
123 unsigned char *ptr, *optr;
124 struct l2tp_session *session;
125 struct l2tp_tunnel *tunnel = NULL;
126 struct iphdr *iph;
127 int length;
128
129 if (!pskb_may_pull(skb, 4))
130 goto discard;
131
132 /* Point to L2TP header */
133 optr = ptr = skb->data;
134 session_id = ntohl(*((__be32 *) ptr));
135 ptr += 4;
136
137 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
138 * the session_id. If it is 0, the packet is a L2TP control
139 * frame and the session_id value can be discarded.
140 */
141 if (session_id == 0) {
142 __skb_pull(skb, 4);
143 goto pass_up;
144 }
145
146 /* Ok, this is a data packet. Lookup the session. */
147 session = l2tp_session_get(net, NULL, session_id);
148 if (!session)
149 goto discard;
150
151 tunnel = session->tunnel;
152 if (!tunnel)
153 goto discard_sess;
154
155 /* Trace packet contents, if enabled */
156 if (tunnel->debug & L2TP_MSG_DATA) {
157 length = min(32u, skb->len);
158 if (!pskb_may_pull(skb, length))
159 goto discard_sess;
160
161 /* Point to L2TP header */
162 optr = ptr = skb->data;
163 ptr += 4;
164 pr_debug("%s: ip recv\n", tunnel->name);
165 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
166 }
167
168 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
169 l2tp_session_dec_refcount(session);
170
171 return 0;
172
173pass_up:
174 /* Get the tunnel_id from the L2TP header */
175 if (!pskb_may_pull(skb, 12))
176 goto discard;
177
178 if ((skb->data[0] & 0xc0) != 0xc0)
179 goto discard;
180
181 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
182 iph = (struct iphdr *)skb_network_header(skb);
183
184 read_lock_bh(&l2tp_ip_lock);
185 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb),
186 tunnel_id);
187 if (!sk) {
188 read_unlock_bh(&l2tp_ip_lock);
189 goto discard;
190 }
191 sock_hold(sk);
192 read_unlock_bh(&l2tp_ip_lock);
193
194 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
195 goto discard_put;
196
197 nf_reset(skb);
198
199 return sk_receive_skb(sk, skb, 1);
200
201discard_sess:
202 l2tp_session_dec_refcount(session);
203 goto discard;
204
205discard_put:
206 sock_put(sk);
207
208discard:
209 kfree_skb(skb);
210 return 0;
211}
212
213static int l2tp_ip_open(struct sock *sk)
214{
215 /* Prevent autobind. We don't have ports. */
216 inet_sk(sk)->inet_num = IPPROTO_L2TP;
217
218 write_lock_bh(&l2tp_ip_lock);
219 sk_add_node(sk, &l2tp_ip_table);
220 write_unlock_bh(&l2tp_ip_lock);
221
222 return 0;
223}
224
225static void l2tp_ip_close(struct sock *sk, long timeout)
226{
227 write_lock_bh(&l2tp_ip_lock);
228 hlist_del_init(&sk->sk_bind_node);
229 sk_del_node_init(sk);
230 write_unlock_bh(&l2tp_ip_lock);
231 sk_common_release(sk);
232}
233
234static void l2tp_ip_destroy_sock(struct sock *sk)
235{
236 struct sk_buff *skb;
237 struct l2tp_tunnel *tunnel = sk->sk_user_data;
238
239 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
240 kfree_skb(skb);
241
242 if (tunnel)
243 l2tp_tunnel_delete(tunnel);
244}
245
246static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
247{
248 struct inet_sock *inet = inet_sk(sk);
249 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
250 struct net *net = sock_net(sk);
251 int ret;
252 int chk_addr_ret;
253
254 if (addr_len < sizeof(struct sockaddr_l2tpip))
255 return -EINVAL;
256 if (addr->l2tp_family != AF_INET)
257 return -EINVAL;
258
259 lock_sock(sk);
260
261 ret = -EINVAL;
262 if (!sock_flag(sk, SOCK_ZAPPED))
263 goto out;
264
265 if (sk->sk_state != TCP_CLOSE)
266 goto out;
267
268 chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
269 ret = -EADDRNOTAVAIL;
270 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
271 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
272 goto out;
273
274 if (addr->l2tp_addr.s_addr)
275 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
276 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
277 inet->inet_saddr = 0; /* Use device */
278
279 write_lock_bh(&l2tp_ip_lock);
280 if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
281 sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
282 write_unlock_bh(&l2tp_ip_lock);
283 ret = -EADDRINUSE;
284 goto out;
285 }
286
287 sk_dst_reset(sk);
288 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
289
290 sk_add_bind_node(sk, &l2tp_ip_bind_table);
291 sk_del_node_init(sk);
292 write_unlock_bh(&l2tp_ip_lock);
293
294 ret = 0;
295 sock_reset_flag(sk, SOCK_ZAPPED);
296
297out:
298 release_sock(sk);
299
300 return ret;
301}
302
303static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
304{
305 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
306 int rc;
307
308 if (addr_len < sizeof(*lsa))
309 return -EINVAL;
310
311 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
312 return -EINVAL;
313
314 lock_sock(sk);
315
316 /* Must bind first - autobinding does not work */
317 if (sock_flag(sk, SOCK_ZAPPED)) {
318 rc = -EINVAL;
319 goto out_sk;
320 }
321
322 rc = __ip4_datagram_connect(sk, uaddr, addr_len);
323 if (rc < 0)
324 goto out_sk;
325
326 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
327
328 write_lock_bh(&l2tp_ip_lock);
329 hlist_del_init(&sk->sk_bind_node);
330 sk_add_bind_node(sk, &l2tp_ip_bind_table);
331 write_unlock_bh(&l2tp_ip_lock);
332
333out_sk:
334 release_sock(sk);
335
336 return rc;
337}
338
339static int l2tp_ip_disconnect(struct sock *sk, int flags)
340{
341 if (sock_flag(sk, SOCK_ZAPPED))
342 return 0;
343
344 return __udp_disconnect(sk, flags);
345}
346
347static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
348 int peer)
349{
350 struct sock *sk = sock->sk;
351 struct inet_sock *inet = inet_sk(sk);
352 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
353 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
354
355 memset(lsa, 0, sizeof(*lsa));
356 lsa->l2tp_family = AF_INET;
357 if (peer) {
358 if (!inet->inet_dport)
359 return -ENOTCONN;
360 lsa->l2tp_conn_id = lsk->peer_conn_id;
361 lsa->l2tp_addr.s_addr = inet->inet_daddr;
362 } else {
363 __be32 addr = inet->inet_rcv_saddr;
364 if (!addr)
365 addr = inet->inet_saddr;
366 lsa->l2tp_conn_id = lsk->conn_id;
367 lsa->l2tp_addr.s_addr = addr;
368 }
369 return sizeof(*lsa);
370}
371
372static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
373{
374 int rc;
375
376 /* Charge it to the socket, dropping if the queue is full. */
377 rc = sock_queue_rcv_skb(sk, skb);
378 if (rc < 0)
379 goto drop;
380
381 return 0;
382
383drop:
384 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
385 kfree_skb(skb);
386 return 0;
387}
388
389/* Userspace will call sendmsg() on the tunnel socket to send L2TP
390 * control frames.
391 */
392static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
393{
394 struct sk_buff *skb;
395 int rc;
396 struct inet_sock *inet = inet_sk(sk);
397 struct rtable *rt = NULL;
398 struct flowi4 *fl4;
399 int connected = 0;
400 __be32 daddr;
401
402 lock_sock(sk);
403
404 rc = -ENOTCONN;
405 if (sock_flag(sk, SOCK_DEAD))
406 goto out;
407
408 /* Get and verify the address. */
409 if (msg->msg_name) {
410 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
411 rc = -EINVAL;
412 if (msg->msg_namelen < sizeof(*lip))
413 goto out;
414
415 if (lip->l2tp_family != AF_INET) {
416 rc = -EAFNOSUPPORT;
417 if (lip->l2tp_family != AF_UNSPEC)
418 goto out;
419 }
420
421 daddr = lip->l2tp_addr.s_addr;
422 } else {
423 rc = -EDESTADDRREQ;
424 if (sk->sk_state != TCP_ESTABLISHED)
425 goto out;
426
427 daddr = inet->inet_daddr;
428 connected = 1;
429 }
430
431 /* Allocate a socket buffer */
432 rc = -ENOMEM;
433 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
434 4 + len, 0, GFP_KERNEL);
435 if (!skb)
436 goto error;
437
438 /* Reserve space for headers, putting IP header on 4-byte boundary. */
439 skb_reserve(skb, 2 + NET_SKB_PAD);
440 skb_reset_network_header(skb);
441 skb_reserve(skb, sizeof(struct iphdr));
442 skb_reset_transport_header(skb);
443
444 /* Insert 0 session_id */
445 *((__be32 *) skb_put(skb, 4)) = 0;
446
447 /* Copy user data into skb */
448 rc = memcpy_from_msg(skb_put(skb, len), msg, len);
449 if (rc < 0) {
450 kfree_skb(skb);
451 goto error;
452 }
453
454 fl4 = &inet->cork.fl.u.ip4;
455 if (connected)
456 rt = (struct rtable *) __sk_dst_check(sk, 0);
457
458 rcu_read_lock();
459 if (rt == NULL) {
460 const struct ip_options_rcu *inet_opt;
461
462 inet_opt = rcu_dereference(inet->inet_opt);
463
464 /* Use correct destination address if we have options. */
465 if (inet_opt && inet_opt->opt.srr)
466 daddr = inet_opt->opt.faddr;
467
468 /* If this fails, retransmit mechanism of transport layer will
469 * keep trying until route appears or the connection times
470 * itself out.
471 */
472 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
473 daddr, inet->inet_saddr,
474 inet->inet_dport, inet->inet_sport,
475 sk->sk_protocol, RT_CONN_FLAGS(sk),
476 sk->sk_bound_dev_if);
477 if (IS_ERR(rt))
478 goto no_route;
479 if (connected) {
480 sk_setup_caps(sk, &rt->dst);
481 } else {
482 skb_dst_set(skb, &rt->dst);
483 goto xmit;
484 }
485 }
486
487 /* We dont need to clone dst here, it is guaranteed to not disappear.
488 * __dev_xmit_skb() might force a refcount if needed.
489 */
490 skb_dst_set_noref(skb, &rt->dst);
491
492xmit:
493 /* Queue the packet to IP for output */
494 rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
495 rcu_read_unlock();
496
497error:
498 if (rc >= 0)
499 rc = len;
500
501out:
502 release_sock(sk);
503 return rc;
504
505no_route:
506 rcu_read_unlock();
507 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
508 kfree_skb(skb);
509 rc = -EHOSTUNREACH;
510 goto out;
511}
512
513static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
514 size_t len, int noblock, int flags, int *addr_len)
515{
516 struct inet_sock *inet = inet_sk(sk);
517 size_t copied = 0;
518 int err = -EOPNOTSUPP;
519 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
520 struct sk_buff *skb;
521
522 if (flags & MSG_OOB)
523 goto out;
524
525 skb = skb_recv_datagram(sk, flags, noblock, &err);
526 if (!skb)
527 goto out;
528
529 copied = skb->len;
530 if (len < copied) {
531 msg->msg_flags |= MSG_TRUNC;
532 copied = len;
533 }
534
535 err = skb_copy_datagram_msg(skb, 0, msg, copied);
536 if (err)
537 goto done;
538
539 sock_recv_timestamp(msg, sk, skb);
540
541 /* Copy the address. */
542 if (sin) {
543 sin->sin_family = AF_INET;
544 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
545 sin->sin_port = 0;
546 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
547 *addr_len = sizeof(*sin);
548 }
549 if (inet->cmsg_flags)
550 ip_cmsg_recv(msg, skb);
551 if (flags & MSG_TRUNC)
552 copied = skb->len;
553done:
554 skb_free_datagram(sk, skb);
555out:
556 return err ? err : copied;
557}
558
559int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
560{
561 struct sk_buff *skb;
562 int amount;
563
564 switch (cmd) {
565 case SIOCOUTQ:
566 amount = sk_wmem_alloc_get(sk);
567 break;
568 case SIOCINQ:
569 spin_lock_bh(&sk->sk_receive_queue.lock);
570 skb = skb_peek(&sk->sk_receive_queue);
571 amount = skb ? skb->len : 0;
572 spin_unlock_bh(&sk->sk_receive_queue.lock);
573 break;
574
575 default:
576 return -ENOIOCTLCMD;
577 }
578
579 return put_user(amount, (int __user *)arg);
580}
581EXPORT_SYMBOL(l2tp_ioctl);
582
583static struct proto l2tp_ip_prot = {
584 .name = "L2TP/IP",
585 .owner = THIS_MODULE,
586 .init = l2tp_ip_open,
587 .close = l2tp_ip_close,
588 .bind = l2tp_ip_bind,
589 .connect = l2tp_ip_connect,
590 .disconnect = l2tp_ip_disconnect,
591 .ioctl = l2tp_ioctl,
592 .destroy = l2tp_ip_destroy_sock,
593 .setsockopt = ip_setsockopt,
594 .getsockopt = ip_getsockopt,
595 .sendmsg = l2tp_ip_sendmsg,
596 .recvmsg = l2tp_ip_recvmsg,
597 .backlog_rcv = l2tp_ip_backlog_recv,
598 .hash = inet_hash,
599 .unhash = inet_unhash,
600 .obj_size = sizeof(struct l2tp_ip_sock),
601#ifdef CONFIG_COMPAT
602 .compat_setsockopt = compat_ip_setsockopt,
603 .compat_getsockopt = compat_ip_getsockopt,
604#endif
605};
606
607static const struct proto_ops l2tp_ip_ops = {
608 .family = PF_INET,
609 .owner = THIS_MODULE,
610 .release = inet_release,
611 .bind = inet_bind,
612 .connect = inet_dgram_connect,
613 .socketpair = sock_no_socketpair,
614 .accept = sock_no_accept,
615 .getname = l2tp_ip_getname,
616 .poll = datagram_poll,
617 .ioctl = inet_ioctl,
618 .listen = sock_no_listen,
619 .shutdown = inet_shutdown,
620 .setsockopt = sock_common_setsockopt,
621 .getsockopt = sock_common_getsockopt,
622 .sendmsg = inet_sendmsg,
623 .recvmsg = sock_common_recvmsg,
624 .mmap = sock_no_mmap,
625 .sendpage = sock_no_sendpage,
626#ifdef CONFIG_COMPAT
627 .compat_setsockopt = compat_sock_common_setsockopt,
628 .compat_getsockopt = compat_sock_common_getsockopt,
629#endif
630};
631
632static struct inet_protosw l2tp_ip_protosw = {
633 .type = SOCK_DGRAM,
634 .protocol = IPPROTO_L2TP,
635 .prot = &l2tp_ip_prot,
636 .ops = &l2tp_ip_ops,
637};
638
639static struct net_protocol l2tp_ip_protocol __read_mostly = {
640 .handler = l2tp_ip_recv,
641 .netns_ok = 1,
642};
643
644static int __init l2tp_ip_init(void)
645{
646 int err;
647
648 pr_info("L2TP IP encapsulation support (L2TPv3)\n");
649
650 err = proto_register(&l2tp_ip_prot, 1);
651 if (err != 0)
652 goto out;
653
654 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
655 if (err)
656 goto out1;
657
658 inet_register_protosw(&l2tp_ip_protosw);
659 return 0;
660
661out1:
662 proto_unregister(&l2tp_ip_prot);
663out:
664 return err;
665}
666
667static void __exit l2tp_ip_exit(void)
668{
669 inet_unregister_protosw(&l2tp_ip_protosw);
670 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
671 proto_unregister(&l2tp_ip_prot);
672}
673
674module_init(l2tp_ip_init);
675module_exit(l2tp_ip_exit);
676
677MODULE_LICENSE("GPL");
678MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
679MODULE_DESCRIPTION("L2TP over IP");
680MODULE_VERSION("1.0");
681
682/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
683 * enums
684 */
685MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
686MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);
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);