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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/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
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(const struct net *net, __be32 laddr,
51 __be32 raddr, int dif, u32 tunnel_id)
52{
53 struct sock *sk;
54
55 sk_for_each_bound(sk, &l2tp_ip_bind_table) {
56 const struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
57 const struct inet_sock *inet = inet_sk(sk);
58
59 if (!net_eq(sock_net(sk), net))
60 continue;
61
62 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
63 continue;
64
65 if (inet->inet_rcv_saddr && laddr &&
66 inet->inet_rcv_saddr != laddr)
67 continue;
68
69 if (inet->inet_daddr && raddr && inet->inet_daddr != raddr)
70 continue;
71
72 if (l2tp->conn_id != tunnel_id)
73 continue;
74
75 goto found;
76 }
77
78 sk = NULL;
79found:
80 return sk;
81}
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115
116static int l2tp_ip_recv(struct sk_buff *skb)
117{
118 struct net *net = dev_net(skb->dev);
119 struct sock *sk;
120 u32 session_id;
121 u32 tunnel_id;
122 unsigned char *ptr, *optr;
123 struct l2tp_session *session;
124 struct l2tp_tunnel *tunnel = NULL;
125 struct iphdr *iph;
126 int length;
127
128 if (!pskb_may_pull(skb, 4))
129 goto discard;
130
131
132 optr = ptr = skb->data;
133 session_id = ntohl(*((__be32 *) ptr));
134 ptr += 4;
135
136
137
138
139
140 if (session_id == 0) {
141 __skb_pull(skb, 4);
142 goto pass_up;
143 }
144
145
146 session = l2tp_session_get(net, NULL, session_id);
147 if (!session)
148 goto discard;
149
150 tunnel = session->tunnel;
151 if (!tunnel)
152 goto discard_sess;
153
154
155 if (tunnel->debug & L2TP_MSG_DATA) {
156 length = min(32u, skb->len);
157 if (!pskb_may_pull(skb, length))
158 goto discard_sess;
159
160
161 optr = ptr = skb->data;
162 ptr += 4;
163 pr_debug("%s: ip recv\n", tunnel->name);
164 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
165 }
166
167 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
168 goto discard_sess;
169
170 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
171 l2tp_session_dec_refcount(session);
172
173 return 0;
174
175pass_up:
176
177 if (!pskb_may_pull(skb, 12))
178 goto discard;
179
180 if ((skb->data[0] & 0xc0) != 0xc0)
181 goto discard;
182
183 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
184 iph = (struct iphdr *)skb_network_header(skb);
185
186 read_lock_bh(&l2tp_ip_lock);
187 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb),
188 tunnel_id);
189 if (!sk) {
190 read_unlock_bh(&l2tp_ip_lock);
191 goto discard;
192 }
193 sock_hold(sk);
194 read_unlock_bh(&l2tp_ip_lock);
195
196 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
197 goto discard_put;
198
199 nf_reset(skb);
200
201 return sk_receive_skb(sk, skb, 1);
202
203discard_sess:
204 l2tp_session_dec_refcount(session);
205 goto discard;
206
207discard_put:
208 sock_put(sk);
209
210discard:
211 kfree_skb(skb);
212 return 0;
213}
214
215static int l2tp_ip_hash(struct sock *sk)
216{
217 if (sk_unhashed(sk)) {
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_unhash(struct sock *sk)
226{
227 if (sk_unhashed(sk))
228 return;
229 write_lock_bh(&l2tp_ip_lock);
230 sk_del_node_init(sk);
231 write_unlock_bh(&l2tp_ip_lock);
232}
233
234static int l2tp_ip_open(struct sock *sk)
235{
236
237 inet_sk(sk)->inet_num = IPPROTO_L2TP;
238
239 l2tp_ip_hash(sk);
240 return 0;
241}
242
243static void l2tp_ip_close(struct sock *sk, long timeout)
244{
245 write_lock_bh(&l2tp_ip_lock);
246 hlist_del_init(&sk->sk_bind_node);
247 sk_del_node_init(sk);
248 write_unlock_bh(&l2tp_ip_lock);
249 sk_common_release(sk);
250}
251
252static void l2tp_ip_destroy_sock(struct sock *sk)
253{
254 struct sk_buff *skb;
255 struct l2tp_tunnel *tunnel = sk->sk_user_data;
256
257 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
258 kfree_skb(skb);
259
260 if (tunnel)
261 l2tp_tunnel_delete(tunnel);
262}
263
264static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
265{
266 struct inet_sock *inet = inet_sk(sk);
267 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
268 struct net *net = sock_net(sk);
269 int ret;
270 int chk_addr_ret;
271
272 if (addr_len < sizeof(struct sockaddr_l2tpip))
273 return -EINVAL;
274 if (addr->l2tp_family != AF_INET)
275 return -EINVAL;
276
277 lock_sock(sk);
278
279 ret = -EINVAL;
280 if (!sock_flag(sk, SOCK_ZAPPED))
281 goto out;
282
283 if (sk->sk_state != TCP_CLOSE)
284 goto out;
285
286 chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
287 ret = -EADDRNOTAVAIL;
288 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
289 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
290 goto out;
291
292 if (addr->l2tp_addr.s_addr)
293 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
294 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
295 inet->inet_saddr = 0;
296
297 write_lock_bh(&l2tp_ip_lock);
298 if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
299 sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
300 write_unlock_bh(&l2tp_ip_lock);
301 ret = -EADDRINUSE;
302 goto out;
303 }
304
305 sk_dst_reset(sk);
306 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
307
308 sk_add_bind_node(sk, &l2tp_ip_bind_table);
309 sk_del_node_init(sk);
310 write_unlock_bh(&l2tp_ip_lock);
311
312 ret = 0;
313 sock_reset_flag(sk, SOCK_ZAPPED);
314
315out:
316 release_sock(sk);
317
318 return ret;
319}
320
321static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
322{
323 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
324 int rc;
325
326 if (addr_len < sizeof(*lsa))
327 return -EINVAL;
328
329 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
330 return -EINVAL;
331
332 lock_sock(sk);
333
334
335 if (sock_flag(sk, SOCK_ZAPPED)) {
336 rc = -EINVAL;
337 goto out_sk;
338 }
339
340 rc = __ip4_datagram_connect(sk, uaddr, addr_len);
341 if (rc < 0)
342 goto out_sk;
343
344 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
345
346 write_lock_bh(&l2tp_ip_lock);
347 hlist_del_init(&sk->sk_bind_node);
348 sk_add_bind_node(sk, &l2tp_ip_bind_table);
349 write_unlock_bh(&l2tp_ip_lock);
350
351out_sk:
352 release_sock(sk);
353
354 return rc;
355}
356
357static int l2tp_ip_disconnect(struct sock *sk, int flags)
358{
359 if (sock_flag(sk, SOCK_ZAPPED))
360 return 0;
361
362 return __udp_disconnect(sk, flags);
363}
364
365static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
366 int peer)
367{
368 struct sock *sk = sock->sk;
369 struct inet_sock *inet = inet_sk(sk);
370 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
371 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
372
373 memset(lsa, 0, sizeof(*lsa));
374 lsa->l2tp_family = AF_INET;
375 if (peer) {
376 if (!inet->inet_dport)
377 return -ENOTCONN;
378 lsa->l2tp_conn_id = lsk->peer_conn_id;
379 lsa->l2tp_addr.s_addr = inet->inet_daddr;
380 } else {
381 __be32 addr = inet->inet_rcv_saddr;
382 if (!addr)
383 addr = inet->inet_saddr;
384 lsa->l2tp_conn_id = lsk->conn_id;
385 lsa->l2tp_addr.s_addr = addr;
386 }
387 return sizeof(*lsa);
388}
389
390static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
391{
392 int rc;
393
394
395 rc = sock_queue_rcv_skb(sk, skb);
396 if (rc < 0)
397 goto drop;
398
399 return 0;
400
401drop:
402 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
403 kfree_skb(skb);
404 return 0;
405}
406
407
408
409
410static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
411{
412 struct sk_buff *skb;
413 int rc;
414 struct inet_sock *inet = inet_sk(sk);
415 struct rtable *rt = NULL;
416 struct flowi4 *fl4;
417 int connected = 0;
418 __be32 daddr;
419
420 lock_sock(sk);
421
422 rc = -ENOTCONN;
423 if (sock_flag(sk, SOCK_DEAD))
424 goto out;
425
426
427 if (msg->msg_name) {
428 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
429 rc = -EINVAL;
430 if (msg->msg_namelen < sizeof(*lip))
431 goto out;
432
433 if (lip->l2tp_family != AF_INET) {
434 rc = -EAFNOSUPPORT;
435 if (lip->l2tp_family != AF_UNSPEC)
436 goto out;
437 }
438
439 daddr = lip->l2tp_addr.s_addr;
440 } else {
441 rc = -EDESTADDRREQ;
442 if (sk->sk_state != TCP_ESTABLISHED)
443 goto out;
444
445 daddr = inet->inet_daddr;
446 connected = 1;
447 }
448
449
450 rc = -ENOMEM;
451 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
452 4 + len, 0, GFP_KERNEL);
453 if (!skb)
454 goto error;
455
456
457 skb_reserve(skb, 2 + NET_SKB_PAD);
458 skb_reset_network_header(skb);
459 skb_reserve(skb, sizeof(struct iphdr));
460 skb_reset_transport_header(skb);
461
462
463 *((__be32 *) skb_put(skb, 4)) = 0;
464
465
466 rc = memcpy_from_msg(skb_put(skb, len), msg, len);
467 if (rc < 0) {
468 kfree_skb(skb);
469 goto error;
470 }
471
472 fl4 = &inet->cork.fl.u.ip4;
473 if (connected)
474 rt = (struct rtable *) __sk_dst_check(sk, 0);
475
476 rcu_read_lock();
477 if (rt == NULL) {
478 const struct ip_options_rcu *inet_opt;
479
480 inet_opt = rcu_dereference(inet->inet_opt);
481
482
483 if (inet_opt && inet_opt->opt.srr)
484 daddr = inet_opt->opt.faddr;
485
486
487
488
489
490 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
491 daddr, inet->inet_saddr,
492 inet->inet_dport, inet->inet_sport,
493 sk->sk_protocol, RT_CONN_FLAGS(sk),
494 sk->sk_bound_dev_if);
495 if (IS_ERR(rt))
496 goto no_route;
497 if (connected) {
498 sk_setup_caps(sk, &rt->dst);
499 } else {
500 skb_dst_set(skb, &rt->dst);
501 goto xmit;
502 }
503 }
504
505
506
507
508 skb_dst_set_noref(skb, &rt->dst);
509
510xmit:
511
512 rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
513 rcu_read_unlock();
514
515error:
516 if (rc >= 0)
517 rc = len;
518
519out:
520 release_sock(sk);
521 return rc;
522
523no_route:
524 rcu_read_unlock();
525 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
526 kfree_skb(skb);
527 rc = -EHOSTUNREACH;
528 goto out;
529}
530
531static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
532 size_t len, int noblock, int flags, int *addr_len)
533{
534 struct inet_sock *inet = inet_sk(sk);
535 size_t copied = 0;
536 int err = -EOPNOTSUPP;
537 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
538 struct sk_buff *skb;
539
540 if (flags & MSG_OOB)
541 goto out;
542
543 skb = skb_recv_datagram(sk, flags, noblock, &err);
544 if (!skb)
545 goto out;
546
547 copied = skb->len;
548 if (len < copied) {
549 msg->msg_flags |= MSG_TRUNC;
550 copied = len;
551 }
552
553 err = skb_copy_datagram_msg(skb, 0, msg, copied);
554 if (err)
555 goto done;
556
557 sock_recv_timestamp(msg, sk, skb);
558
559
560 if (sin) {
561 sin->sin_family = AF_INET;
562 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
563 sin->sin_port = 0;
564 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
565 *addr_len = sizeof(*sin);
566 }
567 if (inet->cmsg_flags)
568 ip_cmsg_recv(msg, skb);
569 if (flags & MSG_TRUNC)
570 copied = skb->len;
571done:
572 skb_free_datagram(sk, skb);
573out:
574 return err ? err : copied;
575}
576
577int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
578{
579 struct sk_buff *skb;
580 int amount;
581
582 switch (cmd) {
583 case SIOCOUTQ:
584 amount = sk_wmem_alloc_get(sk);
585 break;
586 case SIOCINQ:
587 spin_lock_bh(&sk->sk_receive_queue.lock);
588 skb = skb_peek(&sk->sk_receive_queue);
589 amount = skb ? skb->len : 0;
590 spin_unlock_bh(&sk->sk_receive_queue.lock);
591 break;
592
593 default:
594 return -ENOIOCTLCMD;
595 }
596
597 return put_user(amount, (int __user *)arg);
598}
599EXPORT_SYMBOL(l2tp_ioctl);
600
601static struct proto l2tp_ip_prot = {
602 .name = "L2TP/IP",
603 .owner = THIS_MODULE,
604 .init = l2tp_ip_open,
605 .close = l2tp_ip_close,
606 .bind = l2tp_ip_bind,
607 .connect = l2tp_ip_connect,
608 .disconnect = l2tp_ip_disconnect,
609 .ioctl = l2tp_ioctl,
610 .destroy = l2tp_ip_destroy_sock,
611 .setsockopt = ip_setsockopt,
612 .getsockopt = ip_getsockopt,
613 .sendmsg = l2tp_ip_sendmsg,
614 .recvmsg = l2tp_ip_recvmsg,
615 .backlog_rcv = l2tp_ip_backlog_recv,
616 .hash = l2tp_ip_hash,
617 .unhash = l2tp_ip_unhash,
618 .obj_size = sizeof(struct l2tp_ip_sock),
619#ifdef CONFIG_COMPAT
620 .compat_setsockopt = compat_ip_setsockopt,
621 .compat_getsockopt = compat_ip_getsockopt,
622#endif
623};
624
625static const struct proto_ops l2tp_ip_ops = {
626 .family = PF_INET,
627 .owner = THIS_MODULE,
628 .release = inet_release,
629 .bind = inet_bind,
630 .connect = inet_dgram_connect,
631 .socketpair = sock_no_socketpair,
632 .accept = sock_no_accept,
633 .getname = l2tp_ip_getname,
634 .poll = datagram_poll,
635 .ioctl = inet_ioctl,
636 .listen = sock_no_listen,
637 .shutdown = inet_shutdown,
638 .setsockopt = sock_common_setsockopt,
639 .getsockopt = sock_common_getsockopt,
640 .sendmsg = inet_sendmsg,
641 .recvmsg = sock_common_recvmsg,
642 .mmap = sock_no_mmap,
643 .sendpage = sock_no_sendpage,
644#ifdef CONFIG_COMPAT
645 .compat_setsockopt = compat_sock_common_setsockopt,
646 .compat_getsockopt = compat_sock_common_getsockopt,
647#endif
648};
649
650static struct inet_protosw l2tp_ip_protosw = {
651 .type = SOCK_DGRAM,
652 .protocol = IPPROTO_L2TP,
653 .prot = &l2tp_ip_prot,
654 .ops = &l2tp_ip_ops,
655};
656
657static struct net_protocol l2tp_ip_protocol __read_mostly = {
658 .handler = l2tp_ip_recv,
659 .netns_ok = 1,
660};
661
662static int __init l2tp_ip_init(void)
663{
664 int err;
665
666 pr_info("L2TP IP encapsulation support (L2TPv3)\n");
667
668 err = proto_register(&l2tp_ip_prot, 1);
669 if (err != 0)
670 goto out;
671
672 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
673 if (err)
674 goto out1;
675
676 inet_register_protosw(&l2tp_ip_protosw);
677 return 0;
678
679out1:
680 proto_unregister(&l2tp_ip_prot);
681out:
682 return err;
683}
684
685static void __exit l2tp_ip_exit(void)
686{
687 inet_unregister_protosw(&l2tp_ip_protosw);
688 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
689 proto_unregister(&l2tp_ip_prot);
690}
691
692module_init(l2tp_ip_init);
693module_exit(l2tp_ip_exit);
694
695MODULE_LICENSE("GPL");
696MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
697MODULE_DESCRIPTION("L2TP over IP");
698MODULE_VERSION("1.0");
699
700
701
702
703MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
704MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);
705
