1 /*
2 * L2TPv3 IP encapsulation support for IPv6
3 *
4 * Copyright (c) 2012 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 <linux/in6.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/inet6_hashtables.h>
29 #include <net/tcp_states.h>
30 #include <net/protocol.h>
31 #include <net/xfrm.h>
32
33 #include <net/transp_v6.h>
34 #include <net/addrconf.h>
35 #include <net/ip6_route.h>
36
37 #include "l2tp_core.h"
38
39 struct l2tp_ip6_sock {
40 /* inet_sock has to be the first member of l2tp_ip6_sock */
41 struct inet_sock inet;
42
43 u32 conn_id;
44 u32 peer_conn_id;
45
46 /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
47 inet6_sk_generic */
48 struct ipv6_pinfo inet6;
49 };
50
51 static DEFINE_RWLOCK(l2tp_ip6_lock);
52 static struct hlist_head l2tp_ip6_table;
53 static struct hlist_head l2tp_ip6_bind_table;
54
55 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
56 {
57 return (struct l2tp_ip6_sock *)sk;
58 }
59
60 static struct sock *__l2tp_ip6_bind_lookup(const struct net *net,
61 const struct in6_addr *laddr,
62 const struct in6_addr *raddr,
63 int dif, u32 tunnel_id)
64 {
65 struct sock *sk;
66
67 sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
68 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
69 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr;
70 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
71
72 if (!net_eq(sock_net(sk), net))
73 continue;
74
75 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
76 continue;
77
78 if (sk_laddr && !ipv6_addr_any(sk_laddr) &&
79 !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr))
80 continue;
81
82 if (!ipv6_addr_any(sk_raddr) && raddr &&
83 !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr))
84 continue;
85
86 if (l2tp->conn_id != tunnel_id)
87 continue;
88
89 goto found;
90 }
91
92 sk = NULL;
93 found:
94 return sk;
95 }
96
97 /* When processing receive frames, there are two cases to
98 * consider. Data frames consist of a non-zero session-id and an
99 * optional cookie. Control frames consist of a regular L2TP header
100 * preceded by 32-bits of zeros.
101 *
102 * L2TPv3 Session Header Over IP
103 *
104 * 0 1 2 3
105 * 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
106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
107 * | Session ID |
108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
109 * | Cookie (optional, maximum 64 bits)...
110 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
111 * |
112 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
113 *
114 * L2TPv3 Control Message Header Over IP
115 *
116 * 0 1 2 3
117 * 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
118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
119 * | (32 bits of zeros) |
120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
121 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
122 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
123 * | Control Connection ID |
124 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
125 * | Ns | Nr |
126 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
127 *
128 * All control frames are passed to userspace.
129 */
130 static int l2tp_ip6_recv(struct sk_buff *skb)
131 {
132 struct net *net = dev_net(skb->dev);
133 struct sock *sk;
134 u32 session_id;
135 u32 tunnel_id;
136 unsigned char *ptr, *optr;
137 struct l2tp_session *session;
138 struct l2tp_tunnel *tunnel = NULL;
139 struct ipv6hdr *iph;
140 int length;
141
142 if (!pskb_may_pull(skb, 4))
143 goto discard;
144
145 /* Point to L2TP header */
146 optr = ptr = skb->data;
147 session_id = ntohl(*((__be32 *) ptr));
148 ptr += 4;
149
150 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
151 * the session_id. If it is 0, the packet is a L2TP control
152 * frame and the session_id value can be discarded.
153 */
154 if (session_id == 0) {
155 __skb_pull(skb, 4);
156 goto pass_up;
157 }
158
159 /* Ok, this is a data packet. Lookup the session. */
160 session = l2tp_session_get(net, NULL, session_id);
161 if (!session)
162 goto discard;
163
164 tunnel = session->tunnel;
165 if (!tunnel)
166 goto discard_sess;
167
168 /* Trace packet contents, if enabled */
169 if (tunnel->debug & L2TP_MSG_DATA) {
170 length = min(32u, skb->len);
171 if (!pskb_may_pull(skb, length))
172 goto discard_sess;
173
174 /* Point to L2TP header */
175 optr = ptr = skb->data;
176 ptr += 4;
177 pr_debug("%s: ip recv\n", tunnel->name);
178 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
179 }
180
181 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
182 tunnel->recv_payload_hook);
183 l2tp_session_dec_refcount(session);
184
185 return 0;
186
187 pass_up:
188 /* Get the tunnel_id from the L2TP header */
189 if (!pskb_may_pull(skb, 12))
190 goto discard;
191
192 if ((skb->data[0] & 0xc0) != 0xc0)
193 goto discard;
194
195 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
196 iph = ipv6_hdr(skb);
197
198 read_lock_bh(&l2tp_ip6_lock);
199 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
200 inet6_iif(skb), tunnel_id);
201 if (!sk) {
202 read_unlock_bh(&l2tp_ip6_lock);
203 goto discard;
204 }
205 sock_hold(sk);
206 read_unlock_bh(&l2tp_ip6_lock);
207
208 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
209 goto discard_put;
210
211 nf_reset(skb);
212
213 return sk_receive_skb(sk, skb, 1);
214
215 discard_sess:
216 l2tp_session_dec_refcount(session);
217 goto discard;
218
219 discard_put:
220 sock_put(sk);
221
222 discard:
223 kfree_skb(skb);
224 return 0;
225 }
226
227 static int l2tp_ip6_open(struct sock *sk)
228 {
229 /* Prevent autobind. We don't have ports. */
230 inet_sk(sk)->inet_num = IPPROTO_L2TP;
231
232 write_lock_bh(&l2tp_ip6_lock);
233 sk_add_node(sk, &l2tp_ip6_table);
234 write_unlock_bh(&l2tp_ip6_lock);
235
236 return 0;
237 }
238
239 static void l2tp_ip6_close(struct sock *sk, long timeout)
240 {
241 write_lock_bh(&l2tp_ip6_lock);
242 hlist_del_init(&sk->sk_bind_node);
243 sk_del_node_init(sk);
244 write_unlock_bh(&l2tp_ip6_lock);
245
246 sk_common_release(sk);
247 }
248
249 static void l2tp_ip6_destroy_sock(struct sock *sk)
250 {
251 struct l2tp_tunnel *tunnel = sk->sk_user_data;
252
253 lock_sock(sk);
254 ip6_flush_pending_frames(sk);
255 release_sock(sk);
256
257 if (tunnel)
258 l2tp_tunnel_delete(tunnel);
259
260 inet6_destroy_sock(sk);
261 }
262
263 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
264 {
265 struct inet_sock *inet = inet_sk(sk);
266 struct ipv6_pinfo *np = inet6_sk(sk);
267 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
268 struct net *net = sock_net(sk);
269 __be32 v4addr = 0;
270 int bound_dev_if;
271 int addr_type;
272 int err;
273
274 if (addr->l2tp_family != AF_INET6)
275 return -EINVAL;
276 if (addr_len < sizeof(*addr))
277 return -EINVAL;
278
279 addr_type = ipv6_addr_type(&addr->l2tp_addr);
280
281 /* l2tp_ip6 sockets are IPv6 only */
282 if (addr_type == IPV6_ADDR_MAPPED)
283 return -EADDRNOTAVAIL;
284
285 /* L2TP is point-point, not multicast */
286 if (addr_type & IPV6_ADDR_MULTICAST)
287 return -EADDRNOTAVAIL;
288
289 lock_sock(sk);
290
291 err = -EINVAL;
292 if (!sock_flag(sk, SOCK_ZAPPED))
293 goto out_unlock;
294
295 if (sk->sk_state != TCP_CLOSE)
296 goto out_unlock;
297
298 bound_dev_if = sk->sk_bound_dev_if;
299
300 /* Check if the address belongs to the host. */
301 rcu_read_lock();
302 if (addr_type != IPV6_ADDR_ANY) {
303 struct net_device *dev = NULL;
304
305 if (addr_type & IPV6_ADDR_LINKLOCAL) {
306 if (addr->l2tp_scope_id)
307 bound_dev_if = addr->l2tp_scope_id;
308
309 /* Binding to link-local address requires an
310 * interface.
311 */
312 if (!bound_dev_if)
313 goto out_unlock_rcu;
314
315 err = -ENODEV;
316 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
317 if (!dev)
318 goto out_unlock_rcu;
319 }
320
321 /* ipv4 addr of the socket is invalid. Only the
322 * unspecified and mapped address have a v4 equivalent.
323 */
324 v4addr = LOOPBACK4_IPV6;
325 err = -EADDRNOTAVAIL;
326 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
327 goto out_unlock_rcu;
328 }
329 rcu_read_unlock();
330
331 write_lock_bh(&l2tp_ip6_lock);
332 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
333 addr->l2tp_conn_id)) {
334 write_unlock_bh(&l2tp_ip6_lock);
335 err = -EADDRINUSE;
336 goto out_unlock;
337 }
338
339 inet->inet_saddr = v4addr;
340 inet->inet_rcv_saddr = v4addr;
341 sk->sk_bound_dev_if = bound_dev_if;
342 sk->sk_v6_rcv_saddr = addr->l2tp_addr;
343 np->saddr = addr->l2tp_addr;
344
345 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
346
347 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
348 sk_del_node_init(sk);
349 write_unlock_bh(&l2tp_ip6_lock);
350
351 sock_reset_flag(sk, SOCK_ZAPPED);
352 release_sock(sk);
353 return 0;
354
355 out_unlock_rcu:
356 rcu_read_unlock();
357 out_unlock:
358 release_sock(sk);
359
360 return err;
361 }
362
363 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
364 int addr_len)
365 {
366 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
367 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
368 struct in6_addr *daddr;
369 int addr_type;
370 int rc;
371
372 if (addr_len < sizeof(*lsa))
373 return -EINVAL;
374
375 if (usin->sin6_family != AF_INET6)
376 return -EINVAL;
377
378 addr_type = ipv6_addr_type(&usin->sin6_addr);
379 if (addr_type & IPV6_ADDR_MULTICAST)
380 return -EINVAL;
381
382 if (addr_type & IPV6_ADDR_MAPPED) {
383 daddr = &usin->sin6_addr;
384 if (ipv4_is_multicast(daddr->s6_addr32[3]))
385 return -EINVAL;
386 }
387
388 lock_sock(sk);
389
390 /* Must bind first - autobinding does not work */
391 if (sock_flag(sk, SOCK_ZAPPED)) {
392 rc = -EINVAL;
393 goto out_sk;
394 }
395
396 rc = __ip6_datagram_connect(sk, uaddr, addr_len);
397 if (rc < 0)
398 goto out_sk;
399
400 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
401
402 write_lock_bh(&l2tp_ip6_lock);
403 hlist_del_init(&sk->sk_bind_node);
404 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
405 write_unlock_bh(&l2tp_ip6_lock);
406
407 out_sk:
408 release_sock(sk);
409
410 return rc;
411 }
412
413 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
414 {
415 if (sock_flag(sk, SOCK_ZAPPED))
416 return 0;
417
418 return __udp_disconnect(sk, flags);
419 }
420
421 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
422 int *uaddr_len, int peer)
423 {
424 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
425 struct sock *sk = sock->sk;
426 struct ipv6_pinfo *np = inet6_sk(sk);
427 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
428
429 lsa->l2tp_family = AF_INET6;
430 lsa->l2tp_flowinfo = 0;
431 lsa->l2tp_scope_id = 0;
432 lsa->l2tp_unused = 0;
433 if (peer) {
434 if (!lsk->peer_conn_id)
435 return -ENOTCONN;
436 lsa->l2tp_conn_id = lsk->peer_conn_id;
437 lsa->l2tp_addr = sk->sk_v6_daddr;
438 if (np->sndflow)
439 lsa->l2tp_flowinfo = np->flow_label;
440 } else {
441 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
442 lsa->l2tp_addr = np->saddr;
443 else
444 lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
445
446 lsa->l2tp_conn_id = lsk->conn_id;
447 }
448 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
449 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
450 *uaddr_len = sizeof(*lsa);
451 return 0;
452 }
453
454 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
455 {
456 int rc;
457
458 /* Charge it to the socket, dropping if the queue is full. */
459 rc = sock_queue_rcv_skb(sk, skb);
460 if (rc < 0)
461 goto drop;
462
463 return 0;
464
465 drop:
466 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
467 kfree_skb(skb);
468 return -1;
469 }
470
471 static int l2tp_ip6_push_pending_frames(struct sock *sk)
472 {
473 struct sk_buff *skb;
474 __be32 *transhdr = NULL;
475 int err = 0;
476
477 skb = skb_peek(&sk->sk_write_queue);
478 if (skb == NULL)
479 goto out;
480
481 transhdr = (__be32 *)skb_transport_header(skb);
482 *transhdr = 0;
483
484 err = ip6_push_pending_frames(sk);
485
486 out:
487 return err;
488 }
489
490 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
491 * control frames.
492 */
493 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
494 {
495 struct ipv6_txoptions opt_space;
496 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
497 struct in6_addr *daddr, *final_p, final;
498 struct ipv6_pinfo *np = inet6_sk(sk);
499 struct ipv6_txoptions *opt_to_free = NULL;
500 struct ipv6_txoptions *opt = NULL;
501 struct ip6_flowlabel *flowlabel = NULL;
502 struct dst_entry *dst = NULL;
503 struct flowi6 fl6;
504 struct sockcm_cookie sockc_unused = {0};
505 struct ipcm6_cookie ipc6;
506 int addr_len = msg->msg_namelen;
507 int transhdrlen = 4; /* zero session-id */
508 int ulen = len + transhdrlen;
509 int err;
510
511 /* Rough check on arithmetic overflow,
512 better check is made in ip6_append_data().
513 */
514 if (len > INT_MAX)
515 return -EMSGSIZE;
516
517 /* Mirror BSD error message compatibility */
518 if (msg->msg_flags & MSG_OOB)
519 return -EOPNOTSUPP;
520
521 /*
522 * Get and verify the address.
523 */
524 memset(&fl6, 0, sizeof(fl6));
525
526 fl6.flowi6_mark = sk->sk_mark;
527 fl6.flowi6_uid = sk->sk_uid;
528
529 ipc6.hlimit = -1;
530 ipc6.tclass = -1;
531 ipc6.dontfrag = -1;
532
533 if (lsa) {
534 if (addr_len < SIN6_LEN_RFC2133)
535 return -EINVAL;
536
537 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
538 return -EAFNOSUPPORT;
539
540 daddr = &lsa->l2tp_addr;
541 if (np->sndflow) {
542 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
543 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
544 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
545 if (flowlabel == NULL)
546 return -EINVAL;
547 }
548 }
549
550 /*
551 * Otherwise it will be difficult to maintain
552 * sk->sk_dst_cache.
553 */
554 if (sk->sk_state == TCP_ESTABLISHED &&
555 ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
556 daddr = &sk->sk_v6_daddr;
557
558 if (addr_len >= sizeof(struct sockaddr_in6) &&
559 lsa->l2tp_scope_id &&
560 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
561 fl6.flowi6_oif = lsa->l2tp_scope_id;
562 } else {
563 if (sk->sk_state != TCP_ESTABLISHED)
564 return -EDESTADDRREQ;
565
566 daddr = &sk->sk_v6_daddr;
567 fl6.flowlabel = np->flow_label;
568 }
569
570 if (fl6.flowi6_oif == 0)
571 fl6.flowi6_oif = sk->sk_bound_dev_if;
572
573 if (msg->msg_controllen) {
574 opt = &opt_space;
575 memset(opt, 0, sizeof(struct ipv6_txoptions));
576 opt->tot_len = sizeof(struct ipv6_txoptions);
577 ipc6.opt = opt;
578
579 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6,
580 &sockc_unused);
581 if (err < 0) {
582 fl6_sock_release(flowlabel);
583 return err;
584 }
585 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
586 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
587 if (flowlabel == NULL)
588 return -EINVAL;
589 }
590 if (!(opt->opt_nflen|opt->opt_flen))
591 opt = NULL;
592 }
593
594 if (!opt) {
595 opt = txopt_get(np);
596 opt_to_free = opt;
597 }
598 if (flowlabel)
599 opt = fl6_merge_options(&opt_space, flowlabel, opt);
600 opt = ipv6_fixup_options(&opt_space, opt);
601 ipc6.opt = opt;
602
603 fl6.flowi6_proto = sk->sk_protocol;
604 if (!ipv6_addr_any(daddr))
605 fl6.daddr = *daddr;
606 else
607 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
608 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
609 fl6.saddr = np->saddr;
610
611 final_p = fl6_update_dst(&fl6, opt, &final);
612
613 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
614 fl6.flowi6_oif = np->mcast_oif;
615 else if (!fl6.flowi6_oif)
616 fl6.flowi6_oif = np->ucast_oif;
617
618 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
619
620 if (ipc6.tclass < 0)
621 ipc6.tclass = np->tclass;
622
623 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
624
625 dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
626 if (IS_ERR(dst)) {
627 err = PTR_ERR(dst);
628 goto out;
629 }
630
631 if (ipc6.hlimit < 0)
632 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
633
634 if (ipc6.dontfrag < 0)
635 ipc6.dontfrag = np->dontfrag;
636
637 if (msg->msg_flags & MSG_CONFIRM)
638 goto do_confirm;
639
640 back_from_confirm:
641 lock_sock(sk);
642 err = ip6_append_data(sk, ip_generic_getfrag, msg,
643 ulen, transhdrlen, &ipc6,
644 &fl6, (struct rt6_info *)dst,
645 msg->msg_flags, &sockc_unused);
646 if (err)
647 ip6_flush_pending_frames(sk);
648 else if (!(msg->msg_flags & MSG_MORE))
649 err = l2tp_ip6_push_pending_frames(sk);
650 release_sock(sk);
651 done:
652 dst_release(dst);
653 out:
654 fl6_sock_release(flowlabel);
655 txopt_put(opt_to_free);
656
657 return err < 0 ? err : len;
658
659 do_confirm:
660 if (msg->msg_flags & MSG_PROBE)
661 dst_confirm_neigh(dst, &fl6.daddr);
662 if (!(msg->msg_flags & MSG_PROBE) || len)
663 goto back_from_confirm;
664 err = 0;
665 goto done;
666 }
667
668 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
669 int noblock, int flags, int *addr_len)
670 {
671 struct ipv6_pinfo *np = inet6_sk(sk);
672 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
673 size_t copied = 0;
674 int err = -EOPNOTSUPP;
675 struct sk_buff *skb;
676
677 if (flags & MSG_OOB)
678 goto out;
679
680 if (addr_len)
681 *addr_len = sizeof(*lsa);
682
683 if (flags & MSG_ERRQUEUE)
684 return ipv6_recv_error(sk, msg, len, addr_len);
685
686 skb = skb_recv_datagram(sk, flags, noblock, &err);
687 if (!skb)
688 goto out;
689
690 copied = skb->len;
691 if (len < copied) {
692 msg->msg_flags |= MSG_TRUNC;
693 copied = len;
694 }
695
696 err = skb_copy_datagram_msg(skb, 0, msg, copied);
697 if (err)
698 goto done;
699
700 sock_recv_timestamp(msg, sk, skb);
701
702 /* Copy the address. */
703 if (lsa) {
704 lsa->l2tp_family = AF_INET6;
705 lsa->l2tp_unused = 0;
706 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
707 lsa->l2tp_flowinfo = 0;
708 lsa->l2tp_scope_id = 0;
709 lsa->l2tp_conn_id = 0;
710 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
711 lsa->l2tp_scope_id = inet6_iif(skb);
712 }
713
714 if (np->rxopt.all)
715 ip6_datagram_recv_ctl(sk, msg, skb);
716
717 if (flags & MSG_TRUNC)
718 copied = skb->len;
719 done:
720 skb_free_datagram(sk, skb);
721 out:
722 return err ? err : copied;
723 }
724
725 static struct proto l2tp_ip6_prot = {
726 .name = "L2TP/IPv6",
727 .owner = THIS_MODULE,
728 .init = l2tp_ip6_open,
729 .close = l2tp_ip6_close,
730 .bind = l2tp_ip6_bind,
731 .connect = l2tp_ip6_connect,
732 .disconnect = l2tp_ip6_disconnect,
733 .ioctl = l2tp_ioctl,
734 .destroy = l2tp_ip6_destroy_sock,
735 .setsockopt = ipv6_setsockopt,
736 .getsockopt = ipv6_getsockopt,
737 .sendmsg = l2tp_ip6_sendmsg,
738 .recvmsg = l2tp_ip6_recvmsg,
739 .backlog_rcv = l2tp_ip6_backlog_recv,
740 .hash = inet6_hash,
741 .unhash = inet_unhash,
742 .obj_size = sizeof(struct l2tp_ip6_sock),
743 #ifdef CONFIG_COMPAT
744 .compat_setsockopt = compat_ipv6_setsockopt,
745 .compat_getsockopt = compat_ipv6_getsockopt,
746 #endif
747 };
748
749 static const struct proto_ops l2tp_ip6_ops = {
750 .family = PF_INET6,
751 .owner = THIS_MODULE,
752 .release = inet6_release,
753 .bind = inet6_bind,
754 .connect = inet_dgram_connect,
755 .socketpair = sock_no_socketpair,
756 .accept = sock_no_accept,
757 .getname = l2tp_ip6_getname,
758 .poll = datagram_poll,
759 .ioctl = inet6_ioctl,
760 .listen = sock_no_listen,
761 .shutdown = inet_shutdown,
762 .setsockopt = sock_common_setsockopt,
763 .getsockopt = sock_common_getsockopt,
764 .sendmsg = inet_sendmsg,
765 .recvmsg = sock_common_recvmsg,
766 .mmap = sock_no_mmap,
767 .sendpage = sock_no_sendpage,
768 #ifdef CONFIG_COMPAT
769 .compat_setsockopt = compat_sock_common_setsockopt,
770 .compat_getsockopt = compat_sock_common_getsockopt,
771 #endif
772 };
773
774 static struct inet_protosw l2tp_ip6_protosw = {
775 .type = SOCK_DGRAM,
776 .protocol = IPPROTO_L2TP,
777 .prot = &l2tp_ip6_prot,
778 .ops = &l2tp_ip6_ops,
779 };
780
781 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
782 .handler = l2tp_ip6_recv,
783 };
784
785 static int __init l2tp_ip6_init(void)
786 {
787 int err;
788
789 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
790
791 err = proto_register(&l2tp_ip6_prot, 1);
792 if (err != 0)
793 goto out;
794
795 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
796 if (err)
797 goto out1;
798
799 inet6_register_protosw(&l2tp_ip6_protosw);
800 return 0;
801
802 out1:
803 proto_unregister(&l2tp_ip6_prot);
804 out:
805 return err;
806 }
807
808 static void __exit l2tp_ip6_exit(void)
809 {
810 inet6_unregister_protosw(&l2tp_ip6_protosw);
811 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
812 proto_unregister(&l2tp_ip6_prot);
813 }
814
815 module_init(l2tp_ip6_init);
816 module_exit(l2tp_ip6_exit);
817
818 MODULE_LICENSE("GPL");
819 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
820 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
821 MODULE_VERSION("1.0");
822
823 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
824 * enums
825 */
826 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
827 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);
828
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