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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
39struct 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
51static DEFINE_RWLOCK(l2tp_ip6_lock);
52static struct hlist_head l2tp_ip6_table;
53static struct hlist_head l2tp_ip6_bind_table;
54
55static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
56{
57 return (struct l2tp_ip6_sock *)sk;
58}
59
60static 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;
93found:
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 */
130static 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
187pass_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
215discard_sess:
216 l2tp_session_dec_refcount(session);
217 goto discard;
218
219discard_put:
220 sock_put(sk);
221
222discard:
223 kfree_skb(skb);
224 return 0;
225}
226
227static 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
239static 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
249static 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
263static 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
355out_unlock_rcu:
356 rcu_read_unlock();
357out_unlock:
358 release_sock(sk);
359
360 return err;
361}
362
363static 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
407out_sk:
408 release_sock(sk);
409
410 return rc;
411}
412
413static 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
421static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
422 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 return sizeof(*lsa);
451}
452
453static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
454{
455 int rc;
456
457 /* Charge it to the socket, dropping if the queue is full. */
458 rc = sock_queue_rcv_skb(sk, skb);
459 if (rc < 0)
460 goto drop;
461
462 return 0;
463
464drop:
465 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
466 kfree_skb(skb);
467 return -1;
468}
469
470static int l2tp_ip6_push_pending_frames(struct sock *sk)
471{
472 struct sk_buff *skb;
473 __be32 *transhdr = NULL;
474 int err = 0;
475
476 skb = skb_peek(&sk->sk_write_queue);
477 if (skb == NULL)
478 goto out;
479
480 transhdr = (__be32 *)skb_transport_header(skb);
481 *transhdr = 0;
482
483 err = ip6_push_pending_frames(sk);
484
485out:
486 return err;
487}
488
489/* Userspace will call sendmsg() on the tunnel socket to send L2TP
490 * control frames.
491 */
492static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
493{
494 struct ipv6_txoptions opt_space;
495 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
496 struct in6_addr *daddr, *final_p, final;
497 struct ipv6_pinfo *np = inet6_sk(sk);
498 struct ipv6_txoptions *opt_to_free = NULL;
499 struct ipv6_txoptions *opt = NULL;
500 struct ip6_flowlabel *flowlabel = NULL;
501 struct dst_entry *dst = NULL;
502 struct flowi6 fl6;
503 struct sockcm_cookie sockc_unused = {0};
504 struct ipcm6_cookie ipc6;
505 int addr_len = msg->msg_namelen;
506 int transhdrlen = 4; /* zero session-id */
507 int ulen = len + transhdrlen;
508 int err;
509
510 /* Rough check on arithmetic overflow,
511 better check is made in ip6_append_data().
512 */
513 if (len > INT_MAX)
514 return -EMSGSIZE;
515
516 /* Mirror BSD error message compatibility */
517 if (msg->msg_flags & MSG_OOB)
518 return -EOPNOTSUPP;
519
520 /*
521 * Get and verify the address.
522 */
523 memset(&fl6, 0, sizeof(fl6));
524
525 fl6.flowi6_mark = sk->sk_mark;
526 fl6.flowi6_uid = sk->sk_uid;
527
528 ipc6.hlimit = -1;
529 ipc6.tclass = -1;
530 ipc6.dontfrag = -1;
531
532 if (lsa) {
533 if (addr_len < SIN6_LEN_RFC2133)
534 return -EINVAL;
535
536 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
537 return -EAFNOSUPPORT;
538
539 daddr = &lsa->l2tp_addr;
540 if (np->sndflow) {
541 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
542 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
543 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
544 if (flowlabel == NULL)
545 return -EINVAL;
546 }
547 }
548
549 /*
550 * Otherwise it will be difficult to maintain
551 * sk->sk_dst_cache.
552 */
553 if (sk->sk_state == TCP_ESTABLISHED &&
554 ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
555 daddr = &sk->sk_v6_daddr;
556
557 if (addr_len >= sizeof(struct sockaddr_in6) &&
558 lsa->l2tp_scope_id &&
559 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
560 fl6.flowi6_oif = lsa->l2tp_scope_id;
561 } else {
562 if (sk->sk_state != TCP_ESTABLISHED)
563 return -EDESTADDRREQ;
564
565 daddr = &sk->sk_v6_daddr;
566 fl6.flowlabel = np->flow_label;
567 }
568
569 if (fl6.flowi6_oif == 0)
570 fl6.flowi6_oif = sk->sk_bound_dev_if;
571
572 if (msg->msg_controllen) {
573 opt = &opt_space;
574 memset(opt, 0, sizeof(struct ipv6_txoptions));
575 opt->tot_len = sizeof(struct ipv6_txoptions);
576 ipc6.opt = opt;
577
578 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6,
579 &sockc_unused);
580 if (err < 0) {
581 fl6_sock_release(flowlabel);
582 return err;
583 }
584 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
585 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
586 if (flowlabel == NULL)
587 return -EINVAL;
588 }
589 if (!(opt->opt_nflen|opt->opt_flen))
590 opt = NULL;
591 }
592
593 if (!opt) {
594 opt = txopt_get(np);
595 opt_to_free = opt;
596 }
597 if (flowlabel)
598 opt = fl6_merge_options(&opt_space, flowlabel, opt);
599 opt = ipv6_fixup_options(&opt_space, opt);
600 ipc6.opt = opt;
601
602 fl6.flowi6_proto = sk->sk_protocol;
603 if (!ipv6_addr_any(daddr))
604 fl6.daddr = *daddr;
605 else
606 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
607 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
608 fl6.saddr = np->saddr;
609
610 final_p = fl6_update_dst(&fl6, opt, &final);
611
612 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
613 fl6.flowi6_oif = np->mcast_oif;
614 else if (!fl6.flowi6_oif)
615 fl6.flowi6_oif = np->ucast_oif;
616
617 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
618
619 if (ipc6.tclass < 0)
620 ipc6.tclass = np->tclass;
621
622 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
623
624 dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
625 if (IS_ERR(dst)) {
626 err = PTR_ERR(dst);
627 goto out;
628 }
629
630 if (ipc6.hlimit < 0)
631 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
632
633 if (ipc6.dontfrag < 0)
634 ipc6.dontfrag = np->dontfrag;
635
636 if (msg->msg_flags & MSG_CONFIRM)
637 goto do_confirm;
638
639back_from_confirm:
640 lock_sock(sk);
641 err = ip6_append_data(sk, ip_generic_getfrag, msg,
642 ulen, transhdrlen, &ipc6,
643 &fl6, (struct rt6_info *)dst,
644 msg->msg_flags, &sockc_unused);
645 if (err)
646 ip6_flush_pending_frames(sk);
647 else if (!(msg->msg_flags & MSG_MORE))
648 err = l2tp_ip6_push_pending_frames(sk);
649 release_sock(sk);
650done:
651 dst_release(dst);
652out:
653 fl6_sock_release(flowlabel);
654 txopt_put(opt_to_free);
655
656 return err < 0 ? err : len;
657
658do_confirm:
659 if (msg->msg_flags & MSG_PROBE)
660 dst_confirm_neigh(dst, &fl6.daddr);
661 if (!(msg->msg_flags & MSG_PROBE) || len)
662 goto back_from_confirm;
663 err = 0;
664 goto done;
665}
666
667static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
668 int noblock, int flags, int *addr_len)
669{
670 struct ipv6_pinfo *np = inet6_sk(sk);
671 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
672 size_t copied = 0;
673 int err = -EOPNOTSUPP;
674 struct sk_buff *skb;
675
676 if (flags & MSG_OOB)
677 goto out;
678
679 if (addr_len)
680 *addr_len = sizeof(*lsa);
681
682 if (flags & MSG_ERRQUEUE)
683 return ipv6_recv_error(sk, msg, len, addr_len);
684
685 skb = skb_recv_datagram(sk, flags, noblock, &err);
686 if (!skb)
687 goto out;
688
689 copied = skb->len;
690 if (len < copied) {
691 msg->msg_flags |= MSG_TRUNC;
692 copied = len;
693 }
694
695 err = skb_copy_datagram_msg(skb, 0, msg, copied);
696 if (err)
697 goto done;
698
699 sock_recv_timestamp(msg, sk, skb);
700
701 /* Copy the address. */
702 if (lsa) {
703 lsa->l2tp_family = AF_INET6;
704 lsa->l2tp_unused = 0;
705 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
706 lsa->l2tp_flowinfo = 0;
707 lsa->l2tp_scope_id = 0;
708 lsa->l2tp_conn_id = 0;
709 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
710 lsa->l2tp_scope_id = inet6_iif(skb);
711 }
712
713 if (np->rxopt.all)
714 ip6_datagram_recv_ctl(sk, msg, skb);
715
716 if (flags & MSG_TRUNC)
717 copied = skb->len;
718done:
719 skb_free_datagram(sk, skb);
720out:
721 return err ? err : copied;
722}
723
724static struct proto l2tp_ip6_prot = {
725 .name = "L2TP/IPv6",
726 .owner = THIS_MODULE,
727 .init = l2tp_ip6_open,
728 .close = l2tp_ip6_close,
729 .bind = l2tp_ip6_bind,
730 .connect = l2tp_ip6_connect,
731 .disconnect = l2tp_ip6_disconnect,
732 .ioctl = l2tp_ioctl,
733 .destroy = l2tp_ip6_destroy_sock,
734 .setsockopt = ipv6_setsockopt,
735 .getsockopt = ipv6_getsockopt,
736 .sendmsg = l2tp_ip6_sendmsg,
737 .recvmsg = l2tp_ip6_recvmsg,
738 .backlog_rcv = l2tp_ip6_backlog_recv,
739 .hash = inet6_hash,
740 .unhash = inet_unhash,
741 .obj_size = sizeof(struct l2tp_ip6_sock),
742#ifdef CONFIG_COMPAT
743 .compat_setsockopt = compat_ipv6_setsockopt,
744 .compat_getsockopt = compat_ipv6_getsockopt,
745#endif
746};
747
748static const struct proto_ops l2tp_ip6_ops = {
749 .family = PF_INET6,
750 .owner = THIS_MODULE,
751 .release = inet6_release,
752 .bind = inet6_bind,
753 .connect = inet_dgram_connect,
754 .socketpair = sock_no_socketpair,
755 .accept = sock_no_accept,
756 .getname = l2tp_ip6_getname,
757 .poll = datagram_poll,
758 .ioctl = inet6_ioctl,
759 .listen = sock_no_listen,
760 .shutdown = inet_shutdown,
761 .setsockopt = sock_common_setsockopt,
762 .getsockopt = sock_common_getsockopt,
763 .sendmsg = inet_sendmsg,
764 .recvmsg = sock_common_recvmsg,
765 .mmap = sock_no_mmap,
766 .sendpage = sock_no_sendpage,
767#ifdef CONFIG_COMPAT
768 .compat_setsockopt = compat_sock_common_setsockopt,
769 .compat_getsockopt = compat_sock_common_getsockopt,
770#endif
771};
772
773static struct inet_protosw l2tp_ip6_protosw = {
774 .type = SOCK_DGRAM,
775 .protocol = IPPROTO_L2TP,
776 .prot = &l2tp_ip6_prot,
777 .ops = &l2tp_ip6_ops,
778};
779
780static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
781 .handler = l2tp_ip6_recv,
782};
783
784static int __init l2tp_ip6_init(void)
785{
786 int err;
787
788 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
789
790 err = proto_register(&l2tp_ip6_prot, 1);
791 if (err != 0)
792 goto out;
793
794 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
795 if (err)
796 goto out1;
797
798 inet6_register_protosw(&l2tp_ip6_protosw);
799 return 0;
800
801out1:
802 proto_unregister(&l2tp_ip6_prot);
803out:
804 return err;
805}
806
807static void __exit l2tp_ip6_exit(void)
808{
809 inet6_unregister_protosw(&l2tp_ip6_protosw);
810 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
811 proto_unregister(&l2tp_ip6_prot);
812}
813
814module_init(l2tp_ip6_init);
815module_exit(l2tp_ip6_exit);
816
817MODULE_LICENSE("GPL");
818MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
819MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
820MODULE_VERSION("1.0");
821
822/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
823 * enums
824 */
825MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
826MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* L2TPv3 IP encapsulation support for IPv6
3 *
4 * Copyright (c) 2012 Katalix Systems Ltd
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/icmp.h>
10#include <linux/module.h>
11#include <linux/skbuff.h>
12#include <linux/random.h>
13#include <linux/socket.h>
14#include <linux/l2tp.h>
15#include <linux/in.h>
16#include <linux/in6.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
26#include <net/transp_v6.h>
27#include <net/addrconf.h>
28#include <net/ip6_route.h>
29
30#include "l2tp_core.h"
31
32struct l2tp_ip6_sock {
33 /* inet_sock has to be the first member of l2tp_ip6_sock */
34 struct inet_sock inet;
35
36 u32 conn_id;
37 u32 peer_conn_id;
38
39 /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
40 * inet6_sk_generic
41 */
42 struct ipv6_pinfo inet6;
43};
44
45static DEFINE_RWLOCK(l2tp_ip6_lock);
46static struct hlist_head l2tp_ip6_table;
47static struct hlist_head l2tp_ip6_bind_table;
48
49static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
50{
51 return (struct l2tp_ip6_sock *)sk;
52}
53
54static struct sock *__l2tp_ip6_bind_lookup(const struct net *net,
55 const struct in6_addr *laddr,
56 const struct in6_addr *raddr,
57 int dif, u32 tunnel_id)
58{
59 struct sock *sk;
60
61 sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
62 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
63 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr;
64 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
65
66 if (!net_eq(sock_net(sk), net))
67 continue;
68
69 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
70 continue;
71
72 if (sk_laddr && !ipv6_addr_any(sk_laddr) &&
73 !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr))
74 continue;
75
76 if (!ipv6_addr_any(sk_raddr) && raddr &&
77 !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr))
78 continue;
79
80 if (l2tp->conn_id != tunnel_id)
81 continue;
82
83 goto found;
84 }
85
86 sk = NULL;
87found:
88 return sk;
89}
90
91/* When processing receive frames, there are two cases to
92 * consider. Data frames consist of a non-zero session-id and an
93 * optional cookie. Control frames consist of a regular L2TP header
94 * preceded by 32-bits of zeros.
95 *
96 * L2TPv3 Session Header Over IP
97 *
98 * 0 1 2 3
99 * 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
100 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
101 * | Session ID |
102 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
103 * | Cookie (optional, maximum 64 bits)...
104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
105 * |
106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
107 *
108 * L2TPv3 Control Message Header Over IP
109 *
110 * 0 1 2 3
111 * 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
112 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
113 * | (32 bits of zeros) |
114 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
115 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
116 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
117 * | Control Connection ID |
118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
119 * | Ns | Nr |
120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
121 *
122 * All control frames are passed to userspace.
123 */
124static int l2tp_ip6_recv(struct sk_buff *skb)
125{
126 struct net *net = dev_net(skb->dev);
127 struct sock *sk;
128 u32 session_id;
129 u32 tunnel_id;
130 unsigned char *ptr, *optr;
131 struct l2tp_session *session;
132 struct l2tp_tunnel *tunnel = NULL;
133 struct ipv6hdr *iph;
134
135 if (!pskb_may_pull(skb, 4))
136 goto discard;
137
138 /* Point to L2TP header */
139 optr = skb->data;
140 ptr = skb->data;
141 session_id = ntohl(*((__be32 *)ptr));
142 ptr += 4;
143
144 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
145 * the session_id. If it is 0, the packet is a L2TP control
146 * frame and the session_id value can be discarded.
147 */
148 if (session_id == 0) {
149 __skb_pull(skb, 4);
150 goto pass_up;
151 }
152
153 /* Ok, this is a data packet. Lookup the session. */
154 session = l2tp_session_get(net, session_id);
155 if (!session)
156 goto discard;
157
158 tunnel = session->tunnel;
159 if (!tunnel)
160 goto discard_sess;
161
162 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
163 goto discard_sess;
164
165 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
166 l2tp_session_dec_refcount(session);
167
168 return 0;
169
170pass_up:
171 /* Get the tunnel_id from the L2TP header */
172 if (!pskb_may_pull(skb, 12))
173 goto discard;
174
175 if ((skb->data[0] & 0xc0) != 0xc0)
176 goto discard;
177
178 tunnel_id = ntohl(*(__be32 *)&skb->data[4]);
179 iph = ipv6_hdr(skb);
180
181 read_lock_bh(&l2tp_ip6_lock);
182 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
183 inet6_iif(skb), tunnel_id);
184 if (!sk) {
185 read_unlock_bh(&l2tp_ip6_lock);
186 goto discard;
187 }
188 sock_hold(sk);
189 read_unlock_bh(&l2tp_ip6_lock);
190
191 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
192 goto discard_put;
193
194 nf_reset_ct(skb);
195
196 return sk_receive_skb(sk, skb, 1);
197
198discard_sess:
199 l2tp_session_dec_refcount(session);
200 goto discard;
201
202discard_put:
203 sock_put(sk);
204
205discard:
206 kfree_skb(skb);
207 return 0;
208}
209
210static int l2tp_ip6_hash(struct sock *sk)
211{
212 if (sk_unhashed(sk)) {
213 write_lock_bh(&l2tp_ip6_lock);
214 sk_add_node(sk, &l2tp_ip6_table);
215 write_unlock_bh(&l2tp_ip6_lock);
216 }
217 return 0;
218}
219
220static void l2tp_ip6_unhash(struct sock *sk)
221{
222 if (sk_unhashed(sk))
223 return;
224 write_lock_bh(&l2tp_ip6_lock);
225 sk_del_node_init(sk);
226 write_unlock_bh(&l2tp_ip6_lock);
227}
228
229static int l2tp_ip6_open(struct sock *sk)
230{
231 /* Prevent autobind. We don't have ports. */
232 inet_sk(sk)->inet_num = IPPROTO_L2TP;
233
234 l2tp_ip6_hash(sk);
235 return 0;
236}
237
238static void l2tp_ip6_close(struct sock *sk, long timeout)
239{
240 write_lock_bh(&l2tp_ip6_lock);
241 hlist_del_init(&sk->sk_bind_node);
242 sk_del_node_init(sk);
243 write_unlock_bh(&l2tp_ip6_lock);
244
245 sk_common_release(sk);
246}
247
248static void l2tp_ip6_destroy_sock(struct sock *sk)
249{
250 struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk);
251
252 lock_sock(sk);
253 ip6_flush_pending_frames(sk);
254 release_sock(sk);
255
256 if (tunnel)
257 l2tp_tunnel_delete(tunnel);
258
259 inet6_destroy_sock(sk);
260}
261
262static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
263{
264 struct inet_sock *inet = inet_sk(sk);
265 struct ipv6_pinfo *np = inet6_sk(sk);
266 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *)uaddr;
267 struct net *net = sock_net(sk);
268 __be32 v4addr = 0;
269 int bound_dev_if;
270 int addr_type;
271 int err;
272
273 if (addr->l2tp_family != AF_INET6)
274 return -EINVAL;
275 if (addr_len < sizeof(*addr))
276 return -EINVAL;
277
278 addr_type = ipv6_addr_type(&addr->l2tp_addr);
279
280 /* l2tp_ip6 sockets are IPv6 only */
281 if (addr_type == IPV6_ADDR_MAPPED)
282 return -EADDRNOTAVAIL;
283
284 /* L2TP is point-point, not multicast */
285 if (addr_type & IPV6_ADDR_MULTICAST)
286 return -EADDRNOTAVAIL;
287
288 lock_sock(sk);
289
290 err = -EINVAL;
291 if (!sock_flag(sk, SOCK_ZAPPED))
292 goto out_unlock;
293
294 if (sk->sk_state != TCP_CLOSE)
295 goto out_unlock;
296
297 bound_dev_if = sk->sk_bound_dev_if;
298
299 /* Check if the address belongs to the host. */
300 rcu_read_lock();
301 if (addr_type != IPV6_ADDR_ANY) {
302 struct net_device *dev = NULL;
303
304 if (addr_type & IPV6_ADDR_LINKLOCAL) {
305 if (addr->l2tp_scope_id)
306 bound_dev_if = addr->l2tp_scope_id;
307
308 /* Binding to link-local address requires an
309 * interface.
310 */
311 if (!bound_dev_if)
312 goto out_unlock_rcu;
313
314 err = -ENODEV;
315 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
316 if (!dev)
317 goto out_unlock_rcu;
318 }
319
320 /* ipv4 addr of the socket is invalid. Only the
321 * unspecified and mapped address have a v4 equivalent.
322 */
323 v4addr = LOOPBACK4_IPV6;
324 err = -EADDRNOTAVAIL;
325 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
326 goto out_unlock_rcu;
327 }
328 rcu_read_unlock();
329
330 write_lock_bh(&l2tp_ip6_lock);
331 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
332 addr->l2tp_conn_id)) {
333 write_unlock_bh(&l2tp_ip6_lock);
334 err = -EADDRINUSE;
335 goto out_unlock;
336 }
337
338 inet->inet_saddr = v4addr;
339 inet->inet_rcv_saddr = v4addr;
340 sk->sk_bound_dev_if = bound_dev_if;
341 sk->sk_v6_rcv_saddr = addr->l2tp_addr;
342 np->saddr = addr->l2tp_addr;
343
344 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
345
346 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
347 sk_del_node_init(sk);
348 write_unlock_bh(&l2tp_ip6_lock);
349
350 sock_reset_flag(sk, SOCK_ZAPPED);
351 release_sock(sk);
352 return 0;
353
354out_unlock_rcu:
355 rcu_read_unlock();
356out_unlock:
357 release_sock(sk);
358
359 return err;
360}
361
362static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
363 int addr_len)
364{
365 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
366 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
367 struct in6_addr *daddr;
368 int addr_type;
369 int rc;
370
371 if (addr_len < sizeof(*lsa))
372 return -EINVAL;
373
374 if (usin->sin6_family != AF_INET6)
375 return -EINVAL;
376
377 addr_type = ipv6_addr_type(&usin->sin6_addr);
378 if (addr_type & IPV6_ADDR_MULTICAST)
379 return -EINVAL;
380
381 if (addr_type & IPV6_ADDR_MAPPED) {
382 daddr = &usin->sin6_addr;
383 if (ipv4_is_multicast(daddr->s6_addr32[3]))
384 return -EINVAL;
385 }
386
387 lock_sock(sk);
388
389 /* Must bind first - autobinding does not work */
390 if (sock_flag(sk, SOCK_ZAPPED)) {
391 rc = -EINVAL;
392 goto out_sk;
393 }
394
395 rc = __ip6_datagram_connect(sk, uaddr, addr_len);
396 if (rc < 0)
397 goto out_sk;
398
399 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
400
401 write_lock_bh(&l2tp_ip6_lock);
402 hlist_del_init(&sk->sk_bind_node);
403 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
404 write_unlock_bh(&l2tp_ip6_lock);
405
406out_sk:
407 release_sock(sk);
408
409 return rc;
410}
411
412static int l2tp_ip6_disconnect(struct sock *sk, int flags)
413{
414 if (sock_flag(sk, SOCK_ZAPPED))
415 return 0;
416
417 return __udp_disconnect(sk, flags);
418}
419
420static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
421 int peer)
422{
423 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
424 struct sock *sk = sock->sk;
425 struct ipv6_pinfo *np = inet6_sk(sk);
426 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
427
428 lsa->l2tp_family = AF_INET6;
429 lsa->l2tp_flowinfo = 0;
430 lsa->l2tp_scope_id = 0;
431 lsa->l2tp_unused = 0;
432 if (peer) {
433 if (!lsk->peer_conn_id)
434 return -ENOTCONN;
435 lsa->l2tp_conn_id = lsk->peer_conn_id;
436 lsa->l2tp_addr = sk->sk_v6_daddr;
437 if (np->sndflow)
438 lsa->l2tp_flowinfo = np->flow_label;
439 } else {
440 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
441 lsa->l2tp_addr = np->saddr;
442 else
443 lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
444
445 lsa->l2tp_conn_id = lsk->conn_id;
446 }
447 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
448 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
449 return sizeof(*lsa);
450}
451
452static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
453{
454 int rc;
455
456 /* Charge it to the socket, dropping if the queue is full. */
457 rc = sock_queue_rcv_skb(sk, skb);
458 if (rc < 0)
459 goto drop;
460
461 return 0;
462
463drop:
464 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
465 kfree_skb(skb);
466 return -1;
467}
468
469static int l2tp_ip6_push_pending_frames(struct sock *sk)
470{
471 struct sk_buff *skb;
472 __be32 *transhdr = NULL;
473 int err = 0;
474
475 skb = skb_peek(&sk->sk_write_queue);
476 if (!skb)
477 goto out;
478
479 transhdr = (__be32 *)skb_transport_header(skb);
480 *transhdr = 0;
481
482 err = ip6_push_pending_frames(sk);
483
484out:
485 return err;
486}
487
488/* Userspace will call sendmsg() on the tunnel socket to send L2TP
489 * control frames.
490 */
491static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
492{
493 struct ipv6_txoptions opt_space;
494 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
495 struct in6_addr *daddr, *final_p, final;
496 struct ipv6_pinfo *np = inet6_sk(sk);
497 struct ipv6_txoptions *opt_to_free = NULL;
498 struct ipv6_txoptions *opt = NULL;
499 struct ip6_flowlabel *flowlabel = NULL;
500 struct dst_entry *dst = NULL;
501 struct flowi6 fl6;
502 struct ipcm6_cookie ipc6;
503 int addr_len = msg->msg_namelen;
504 int transhdrlen = 4; /* zero session-id */
505 int ulen = len + transhdrlen;
506 int err;
507
508 /* Rough check on arithmetic overflow,
509 * better check is made in ip6_append_data().
510 */
511 if (len > INT_MAX)
512 return -EMSGSIZE;
513
514 /* Mirror BSD error message compatibility */
515 if (msg->msg_flags & MSG_OOB)
516 return -EOPNOTSUPP;
517
518 /* Get and verify the address */
519 memset(&fl6, 0, sizeof(fl6));
520
521 fl6.flowi6_mark = sk->sk_mark;
522 fl6.flowi6_uid = sk->sk_uid;
523
524 ipcm6_init(&ipc6);
525
526 if (lsa) {
527 if (addr_len < SIN6_LEN_RFC2133)
528 return -EINVAL;
529
530 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
531 return -EAFNOSUPPORT;
532
533 daddr = &lsa->l2tp_addr;
534 if (np->sndflow) {
535 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
536 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
537 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
538 if (IS_ERR(flowlabel))
539 return -EINVAL;
540 }
541 }
542
543 /* Otherwise it will be difficult to maintain
544 * sk->sk_dst_cache.
545 */
546 if (sk->sk_state == TCP_ESTABLISHED &&
547 ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
548 daddr = &sk->sk_v6_daddr;
549
550 if (addr_len >= sizeof(struct sockaddr_in6) &&
551 lsa->l2tp_scope_id &&
552 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
553 fl6.flowi6_oif = lsa->l2tp_scope_id;
554 } else {
555 if (sk->sk_state != TCP_ESTABLISHED)
556 return -EDESTADDRREQ;
557
558 daddr = &sk->sk_v6_daddr;
559 fl6.flowlabel = np->flow_label;
560 }
561
562 if (fl6.flowi6_oif == 0)
563 fl6.flowi6_oif = sk->sk_bound_dev_if;
564
565 if (msg->msg_controllen) {
566 opt = &opt_space;
567 memset(opt, 0, sizeof(struct ipv6_txoptions));
568 opt->tot_len = sizeof(struct ipv6_txoptions);
569 ipc6.opt = opt;
570
571 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6);
572 if (err < 0) {
573 fl6_sock_release(flowlabel);
574 return err;
575 }
576 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
577 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
578 if (IS_ERR(flowlabel))
579 return -EINVAL;
580 }
581 if (!(opt->opt_nflen | opt->opt_flen))
582 opt = NULL;
583 }
584
585 if (!opt) {
586 opt = txopt_get(np);
587 opt_to_free = opt;
588 }
589 if (flowlabel)
590 opt = fl6_merge_options(&opt_space, flowlabel, opt);
591 opt = ipv6_fixup_options(&opt_space, opt);
592 ipc6.opt = opt;
593
594 fl6.flowi6_proto = sk->sk_protocol;
595 if (!ipv6_addr_any(daddr))
596 fl6.daddr = *daddr;
597 else
598 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
599 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
600 fl6.saddr = np->saddr;
601
602 final_p = fl6_update_dst(&fl6, opt, &final);
603
604 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
605 fl6.flowi6_oif = np->mcast_oif;
606 else if (!fl6.flowi6_oif)
607 fl6.flowi6_oif = np->ucast_oif;
608
609 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6));
610
611 if (ipc6.tclass < 0)
612 ipc6.tclass = np->tclass;
613
614 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
615
616 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
617 if (IS_ERR(dst)) {
618 err = PTR_ERR(dst);
619 goto out;
620 }
621
622 if (ipc6.hlimit < 0)
623 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
624
625 if (ipc6.dontfrag < 0)
626 ipc6.dontfrag = np->dontfrag;
627
628 if (msg->msg_flags & MSG_CONFIRM)
629 goto do_confirm;
630
631back_from_confirm:
632 lock_sock(sk);
633 err = ip6_append_data(sk, ip_generic_getfrag, msg,
634 ulen, transhdrlen, &ipc6,
635 &fl6, (struct rt6_info *)dst,
636 msg->msg_flags);
637 if (err)
638 ip6_flush_pending_frames(sk);
639 else if (!(msg->msg_flags & MSG_MORE))
640 err = l2tp_ip6_push_pending_frames(sk);
641 release_sock(sk);
642done:
643 dst_release(dst);
644out:
645 fl6_sock_release(flowlabel);
646 txopt_put(opt_to_free);
647
648 return err < 0 ? err : len;
649
650do_confirm:
651 if (msg->msg_flags & MSG_PROBE)
652 dst_confirm_neigh(dst, &fl6.daddr);
653 if (!(msg->msg_flags & MSG_PROBE) || len)
654 goto back_from_confirm;
655 err = 0;
656 goto done;
657}
658
659static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
660 int noblock, int flags, int *addr_len)
661{
662 struct ipv6_pinfo *np = inet6_sk(sk);
663 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
664 size_t copied = 0;
665 int err = -EOPNOTSUPP;
666 struct sk_buff *skb;
667
668 if (flags & MSG_OOB)
669 goto out;
670
671 if (flags & MSG_ERRQUEUE)
672 return ipv6_recv_error(sk, msg, len, addr_len);
673
674 skb = skb_recv_datagram(sk, flags, noblock, &err);
675 if (!skb)
676 goto out;
677
678 copied = skb->len;
679 if (len < copied) {
680 msg->msg_flags |= MSG_TRUNC;
681 copied = len;
682 }
683
684 err = skb_copy_datagram_msg(skb, 0, msg, copied);
685 if (err)
686 goto done;
687
688 sock_recv_timestamp(msg, sk, skb);
689
690 /* Copy the address. */
691 if (lsa) {
692 lsa->l2tp_family = AF_INET6;
693 lsa->l2tp_unused = 0;
694 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
695 lsa->l2tp_flowinfo = 0;
696 lsa->l2tp_scope_id = 0;
697 lsa->l2tp_conn_id = 0;
698 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
699 lsa->l2tp_scope_id = inet6_iif(skb);
700 *addr_len = sizeof(*lsa);
701 }
702
703 if (np->rxopt.all)
704 ip6_datagram_recv_ctl(sk, msg, skb);
705
706 if (flags & MSG_TRUNC)
707 copied = skb->len;
708done:
709 skb_free_datagram(sk, skb);
710out:
711 return err ? err : copied;
712}
713
714static struct proto l2tp_ip6_prot = {
715 .name = "L2TP/IPv6",
716 .owner = THIS_MODULE,
717 .init = l2tp_ip6_open,
718 .close = l2tp_ip6_close,
719 .bind = l2tp_ip6_bind,
720 .connect = l2tp_ip6_connect,
721 .disconnect = l2tp_ip6_disconnect,
722 .ioctl = l2tp_ioctl,
723 .destroy = l2tp_ip6_destroy_sock,
724 .setsockopt = ipv6_setsockopt,
725 .getsockopt = ipv6_getsockopt,
726 .sendmsg = l2tp_ip6_sendmsg,
727 .recvmsg = l2tp_ip6_recvmsg,
728 .backlog_rcv = l2tp_ip6_backlog_recv,
729 .hash = l2tp_ip6_hash,
730 .unhash = l2tp_ip6_unhash,
731 .obj_size = sizeof(struct l2tp_ip6_sock),
732};
733
734static const struct proto_ops l2tp_ip6_ops = {
735 .family = PF_INET6,
736 .owner = THIS_MODULE,
737 .release = inet6_release,
738 .bind = inet6_bind,
739 .connect = inet_dgram_connect,
740 .socketpair = sock_no_socketpair,
741 .accept = sock_no_accept,
742 .getname = l2tp_ip6_getname,
743 .poll = datagram_poll,
744 .ioctl = inet6_ioctl,
745 .gettstamp = sock_gettstamp,
746 .listen = sock_no_listen,
747 .shutdown = inet_shutdown,
748 .setsockopt = sock_common_setsockopt,
749 .getsockopt = sock_common_getsockopt,
750 .sendmsg = inet_sendmsg,
751 .recvmsg = sock_common_recvmsg,
752 .mmap = sock_no_mmap,
753 .sendpage = sock_no_sendpage,
754#ifdef CONFIG_COMPAT
755 .compat_ioctl = inet6_compat_ioctl,
756#endif
757};
758
759static struct inet_protosw l2tp_ip6_protosw = {
760 .type = SOCK_DGRAM,
761 .protocol = IPPROTO_L2TP,
762 .prot = &l2tp_ip6_prot,
763 .ops = &l2tp_ip6_ops,
764};
765
766static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
767 .handler = l2tp_ip6_recv,
768};
769
770static int __init l2tp_ip6_init(void)
771{
772 int err;
773
774 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
775
776 err = proto_register(&l2tp_ip6_prot, 1);
777 if (err != 0)
778 goto out;
779
780 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
781 if (err)
782 goto out1;
783
784 inet6_register_protosw(&l2tp_ip6_protosw);
785 return 0;
786
787out1:
788 proto_unregister(&l2tp_ip6_prot);
789out:
790 return err;
791}
792
793static void __exit l2tp_ip6_exit(void)
794{
795 inet6_unregister_protosw(&l2tp_ip6_protosw);
796 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
797 proto_unregister(&l2tp_ip6_prot);
798}
799
800module_init(l2tp_ip6_init);
801module_exit(l2tp_ip6_exit);
802
803MODULE_LICENSE("GPL");
804MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
805MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
806MODULE_VERSION("1.0");
807
808/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
809 * enums
810 */
811MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
812MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);