1
2
3
4
5
6
7
8
9
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
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
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
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
133 optr = ptr = skb->data;
134 session_id = ntohl(*((__be32 *) ptr));
135 ptr += 4;
136
137
138
139
140
141 if (session_id == 0) {
142 __skb_pull(skb, 4);
143 goto pass_up;
144 }
145
146
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
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
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
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
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;
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
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
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
390
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
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
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
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
445 *((__be32 *) skb_put(skb, 4)) = 0;
446
447
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
465 if (inet_opt && inet_opt->opt.srr)
466 daddr = inet_opt->opt.faddr;
467
468
469
470
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
488
489
490 skb_dst_set_noref(skb, &rt->dst);
491
492xmit:
493
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
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
683
684
685MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
686MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);
687
