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8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <asm/ioctls.h>
11#include <linux/icmp.h>
12#include <linux/module.h>
13#include <linux/skbuff.h>
14#include <linux/random.h>
15#include <linux/socket.h>
16#include <linux/l2tp.h>
17#include <linux/in.h>
18#include <net/sock.h>
19#include <net/ip.h>
20#include <net/icmp.h>
21#include <net/udp.h>
22#include <net/inet_common.h>
23#include <net/inet_hashtables.h>
24#include <net/tcp_states.h>
25#include <net/protocol.h>
26#include <net/xfrm.h>
27
28#include "l2tp_core.h"
29
30struct l2tp_ip_sock {
31
32 struct inet_sock inet;
33
34 u32 conn_id;
35 u32 peer_conn_id;
36};
37
38static DEFINE_RWLOCK(l2tp_ip_lock);
39static struct hlist_head l2tp_ip_table;
40static struct hlist_head l2tp_ip_bind_table;
41
42static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
43{
44 return (struct l2tp_ip_sock *)sk;
45}
46
47static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
48 __be32 raddr, int dif, u32 tunnel_id)
49{
50 struct sock *sk;
51
52 sk_for_each_bound(sk, &l2tp_ip_bind_table) {
53 const struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
54 const struct inet_sock *inet = inet_sk(sk);
55
56 if (!net_eq(sock_net(sk), net))
57 continue;
58
59 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
60 continue;
61
62 if (inet->inet_rcv_saddr && laddr &&
63 inet->inet_rcv_saddr != laddr)
64 continue;
65
66 if (inet->inet_daddr && raddr && inet->inet_daddr != raddr)
67 continue;
68
69 if (l2tp->conn_id != tunnel_id)
70 continue;
71
72 goto found;
73 }
74
75 sk = NULL;
76found:
77 return sk;
78}
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112
113static int l2tp_ip_recv(struct sk_buff *skb)
114{
115 struct net *net = dev_net(skb->dev);
116 struct sock *sk;
117 u32 session_id;
118 u32 tunnel_id;
119 unsigned char *ptr, *optr;
120 struct l2tp_session *session;
121 struct l2tp_tunnel *tunnel = NULL;
122 struct iphdr *iph;
123 int length;
124
125 if (!pskb_may_pull(skb, 4))
126 goto discard;
127
128
129 optr = ptr = skb->data;
130 session_id = ntohl(*((__be32 *) ptr));
131 ptr += 4;
132
133
134
135
136
137 if (session_id == 0) {
138 __skb_pull(skb, 4);
139 goto pass_up;
140 }
141
142
143 session = l2tp_session_get(net, session_id);
144 if (!session)
145 goto discard;
146
147 tunnel = session->tunnel;
148 if (!tunnel)
149 goto discard_sess;
150
151
152 if (tunnel->debug & L2TP_MSG_DATA) {
153 length = min(32u, skb->len);
154 if (!pskb_may_pull(skb, length))
155 goto discard_sess;
156
157
158 optr = ptr = skb->data;
159 ptr += 4;
160 pr_debug("%s: ip recv\n", tunnel->name);
161 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
162 }
163
164 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
165 goto discard_sess;
166
167 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
168 l2tp_session_dec_refcount(session);
169
170 return 0;
171
172pass_up:
173
174 if (!pskb_may_pull(skb, 12))
175 goto discard;
176
177 if ((skb->data[0] & 0xc0) != 0xc0)
178 goto discard;
179
180 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
181 iph = (struct iphdr *)skb_network_header(skb);
182
183 read_lock_bh(&l2tp_ip_lock);
184 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb),
185 tunnel_id);
186 if (!sk) {
187 read_unlock_bh(&l2tp_ip_lock);
188 goto discard;
189 }
190 sock_hold(sk);
191 read_unlock_bh(&l2tp_ip_lock);
192
193 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
194 goto discard_put;
195
196 nf_reset(skb);
197
198 return sk_receive_skb(sk, skb, 1);
199
200discard_sess:
201 l2tp_session_dec_refcount(session);
202 goto discard;
203
204discard_put:
205 sock_put(sk);
206
207discard:
208 kfree_skb(skb);
209 return 0;
210}
211
212static int l2tp_ip_open(struct sock *sk)
213{
214
215 inet_sk(sk)->inet_num = IPPROTO_L2TP;
216
217 write_lock_bh(&l2tp_ip_lock);
218 sk_add_node(sk, &l2tp_ip_table);
219 write_unlock_bh(&l2tp_ip_lock);
220
221 return 0;
222}
223
224static void l2tp_ip_close(struct sock *sk, long timeout)
225{
226 write_lock_bh(&l2tp_ip_lock);
227 hlist_del_init(&sk->sk_bind_node);
228 sk_del_node_init(sk);
229 write_unlock_bh(&l2tp_ip_lock);
230 sk_common_release(sk);
231}
232
233static void l2tp_ip_destroy_sock(struct sock *sk)
234{
235 struct sk_buff *skb;
236 struct l2tp_tunnel *tunnel = sk->sk_user_data;
237
238 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
239 kfree_skb(skb);
240
241 if (tunnel)
242 l2tp_tunnel_delete(tunnel);
243}
244
245static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
246{
247 struct inet_sock *inet = inet_sk(sk);
248 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
249 struct net *net = sock_net(sk);
250 int ret;
251 int chk_addr_ret;
252
253 if (addr_len < sizeof(struct sockaddr_l2tpip))
254 return -EINVAL;
255 if (addr->l2tp_family != AF_INET)
256 return -EINVAL;
257
258 lock_sock(sk);
259
260 ret = -EINVAL;
261 if (!sock_flag(sk, SOCK_ZAPPED))
262 goto out;
263
264 if (sk->sk_state != TCP_CLOSE)
265 goto out;
266
267 chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
268 ret = -EADDRNOTAVAIL;
269 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
270 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
271 goto out;
272
273 if (addr->l2tp_addr.s_addr)
274 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
275 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
276 inet->inet_saddr = 0;
277
278 write_lock_bh(&l2tp_ip_lock);
279 if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
280 sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
281 write_unlock_bh(&l2tp_ip_lock);
282 ret = -EADDRINUSE;
283 goto out;
284 }
285
286 sk_dst_reset(sk);
287 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
288
289 sk_add_bind_node(sk, &l2tp_ip_bind_table);
290 sk_del_node_init(sk);
291 write_unlock_bh(&l2tp_ip_lock);
292
293 ret = 0;
294 sock_reset_flag(sk, SOCK_ZAPPED);
295
296out:
297 release_sock(sk);
298
299 return ret;
300}
301
302static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
303{
304 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
305 int rc;
306
307 if (addr_len < sizeof(*lsa))
308 return -EINVAL;
309
310 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
311 return -EINVAL;
312
313 lock_sock(sk);
314
315
316 if (sock_flag(sk, SOCK_ZAPPED)) {
317 rc = -EINVAL;
318 goto out_sk;
319 }
320
321 rc = __ip4_datagram_connect(sk, uaddr, addr_len);
322 if (rc < 0)
323 goto out_sk;
324
325 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
326
327 write_lock_bh(&l2tp_ip_lock);
328 hlist_del_init(&sk->sk_bind_node);
329 sk_add_bind_node(sk, &l2tp_ip_bind_table);
330 write_unlock_bh(&l2tp_ip_lock);
331
332out_sk:
333 release_sock(sk);
334
335 return rc;
336}
337
338static int l2tp_ip_disconnect(struct sock *sk, int flags)
339{
340 if (sock_flag(sk, SOCK_ZAPPED))
341 return 0;
342
343 return __udp_disconnect(sk, flags);
344}
345
346static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
347 int peer)
348{
349 struct sock *sk = sock->sk;
350 struct inet_sock *inet = inet_sk(sk);
351 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
352 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
353
354 memset(lsa, 0, sizeof(*lsa));
355 lsa->l2tp_family = AF_INET;
356 if (peer) {
357 if (!inet->inet_dport)
358 return -ENOTCONN;
359 lsa->l2tp_conn_id = lsk->peer_conn_id;
360 lsa->l2tp_addr.s_addr = inet->inet_daddr;
361 } else {
362 __be32 addr = inet->inet_rcv_saddr;
363 if (!addr)
364 addr = inet->inet_saddr;
365 lsa->l2tp_conn_id = lsk->conn_id;
366 lsa->l2tp_addr.s_addr = addr;
367 }
368 return sizeof(*lsa);
369}
370
371static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
372{
373 int rc;
374
375
376 rc = sock_queue_rcv_skb(sk, skb);
377 if (rc < 0)
378 goto drop;
379
380 return 0;
381
382drop:
383 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
384 kfree_skb(skb);
385 return 0;
386}
387
388
389
390
391static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
392{
393 struct sk_buff *skb;
394 int rc;
395 struct inet_sock *inet = inet_sk(sk);
396 struct rtable *rt = NULL;
397 struct flowi4 *fl4;
398 int connected = 0;
399 __be32 daddr;
400
401 lock_sock(sk);
402
403 rc = -ENOTCONN;
404 if (sock_flag(sk, SOCK_DEAD))
405 goto out;
406
407
408 if (msg->msg_name) {
409 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
410 rc = -EINVAL;
411 if (msg->msg_namelen < sizeof(*lip))
412 goto out;
413
414 if (lip->l2tp_family != AF_INET) {
415 rc = -EAFNOSUPPORT;
416 if (lip->l2tp_family != AF_UNSPEC)
417 goto out;
418 }
419
420 daddr = lip->l2tp_addr.s_addr;
421 } else {
422 rc = -EDESTADDRREQ;
423 if (sk->sk_state != TCP_ESTABLISHED)
424 goto out;
425
426 daddr = inet->inet_daddr;
427 connected = 1;
428 }
429
430
431 rc = -ENOMEM;
432 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
433 4 + len, 0, GFP_KERNEL);
434 if (!skb)
435 goto error;
436
437
438 skb_reserve(skb, 2 + NET_SKB_PAD);
439 skb_reset_network_header(skb);
440 skb_reserve(skb, sizeof(struct iphdr));
441 skb_reset_transport_header(skb);
442
443
444 *((__be32 *) skb_put(skb, 4)) = 0;
445
446
447 rc = memcpy_from_msg(skb_put(skb, len), msg, len);
448 if (rc < 0) {
449 kfree_skb(skb);
450 goto error;
451 }
452
453 fl4 = &inet->cork.fl.u.ip4;
454 if (connected)
455 rt = (struct rtable *) __sk_dst_check(sk, 0);
456
457 rcu_read_lock();
458 if (rt == NULL) {
459 const struct ip_options_rcu *inet_opt;
460
461 inet_opt = rcu_dereference(inet->inet_opt);
462
463
464 if (inet_opt && inet_opt->opt.srr)
465 daddr = inet_opt->opt.faddr;
466
467
468
469
470
471 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
472 daddr, inet->inet_saddr,
473 inet->inet_dport, inet->inet_sport,
474 sk->sk_protocol, RT_CONN_FLAGS(sk),
475 sk->sk_bound_dev_if);
476 if (IS_ERR(rt))
477 goto no_route;
478 if (connected) {
479 sk_setup_caps(sk, &rt->dst);
480 } else {
481 skb_dst_set(skb, &rt->dst);
482 goto xmit;
483 }
484 }
485
486
487
488
489 skb_dst_set_noref(skb, &rt->dst);
490
491xmit:
492
493 rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
494 rcu_read_unlock();
495
496error:
497 if (rc >= 0)
498 rc = len;
499
500out:
501 release_sock(sk);
502 return rc;
503
504no_route:
505 rcu_read_unlock();
506 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
507 kfree_skb(skb);
508 rc = -EHOSTUNREACH;
509 goto out;
510}
511
512static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
513 size_t len, int noblock, int flags, int *addr_len)
514{
515 struct inet_sock *inet = inet_sk(sk);
516 size_t copied = 0;
517 int err = -EOPNOTSUPP;
518 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
519 struct sk_buff *skb;
520
521 if (flags & MSG_OOB)
522 goto out;
523
524 skb = skb_recv_datagram(sk, flags, noblock, &err);
525 if (!skb)
526 goto out;
527
528 copied = skb->len;
529 if (len < copied) {
530 msg->msg_flags |= MSG_TRUNC;
531 copied = len;
532 }
533
534 err = skb_copy_datagram_msg(skb, 0, msg, copied);
535 if (err)
536 goto done;
537
538 sock_recv_timestamp(msg, sk, skb);
539
540
541 if (sin) {
542 sin->sin_family = AF_INET;
543 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
544 sin->sin_port = 0;
545 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
546 *addr_len = sizeof(*sin);
547 }
548 if (inet->cmsg_flags)
549 ip_cmsg_recv(msg, skb);
550 if (flags & MSG_TRUNC)
551 copied = skb->len;
552done:
553 skb_free_datagram(sk, skb);
554out:
555 return err ? err : copied;
556}
557
558int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
559{
560 struct sk_buff *skb;
561 int amount;
562
563 switch (cmd) {
564 case SIOCOUTQ:
565 amount = sk_wmem_alloc_get(sk);
566 break;
567 case SIOCINQ:
568 spin_lock_bh(&sk->sk_receive_queue.lock);
569 skb = skb_peek(&sk->sk_receive_queue);
570 amount = skb ? skb->len : 0;
571 spin_unlock_bh(&sk->sk_receive_queue.lock);
572 break;
573
574 default:
575 return -ENOIOCTLCMD;
576 }
577
578 return put_user(amount, (int __user *)arg);
579}
580EXPORT_SYMBOL(l2tp_ioctl);
581
582static struct proto l2tp_ip_prot = {
583 .name = "L2TP/IP",
584 .owner = THIS_MODULE,
585 .init = l2tp_ip_open,
586 .close = l2tp_ip_close,
587 .bind = l2tp_ip_bind,
588 .connect = l2tp_ip_connect,
589 .disconnect = l2tp_ip_disconnect,
590 .ioctl = l2tp_ioctl,
591 .destroy = l2tp_ip_destroy_sock,
592 .setsockopt = ip_setsockopt,
593 .getsockopt = ip_getsockopt,
594 .sendmsg = l2tp_ip_sendmsg,
595 .recvmsg = l2tp_ip_recvmsg,
596 .backlog_rcv = l2tp_ip_backlog_recv,
597 .hash = inet_hash,
598 .unhash = inet_unhash,
599 .obj_size = sizeof(struct l2tp_ip_sock),
600#ifdef CONFIG_COMPAT
601 .compat_setsockopt = compat_ip_setsockopt,
602 .compat_getsockopt = compat_ip_getsockopt,
603#endif
604};
605
606static const struct proto_ops l2tp_ip_ops = {
607 .family = PF_INET,
608 .owner = THIS_MODULE,
609 .release = inet_release,
610 .bind = inet_bind,
611 .connect = inet_dgram_connect,
612 .socketpair = sock_no_socketpair,
613 .accept = sock_no_accept,
614 .getname = l2tp_ip_getname,
615 .poll = datagram_poll,
616 .ioctl = inet_ioctl,
617 .gettstamp = sock_gettstamp,
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
683
684
685MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
686MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);
687
