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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/tcp_states.h>
29#include <net/protocol.h>
30#include <net/xfrm.h>
31
32#include <net/transp_v6.h>
33#include <net/addrconf.h>
34#include <net/ip6_route.h>
35
36#include "l2tp_core.h"
37
38struct l2tp_ip6_sock {
39 /* inet_sock has to be the first member of l2tp_ip6_sock */
40 struct inet_sock inet;
41
42 u32 conn_id;
43 u32 peer_conn_id;
44
45 /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
46 inet6_sk_generic */
47 struct ipv6_pinfo inet6;
48};
49
50static DEFINE_RWLOCK(l2tp_ip6_lock);
51static struct hlist_head l2tp_ip6_table;
52static struct hlist_head l2tp_ip6_bind_table;
53
54static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
55{
56 return (struct l2tp_ip6_sock *)sk;
57}
58
59static struct sock *__l2tp_ip6_bind_lookup(struct net *net,
60 struct in6_addr *laddr,
61 int dif, u32 tunnel_id)
62{
63 struct hlist_node *node;
64 struct sock *sk;
65
66 sk_for_each_bound(sk, node, &l2tp_ip6_bind_table) {
67 struct in6_addr *addr = inet6_rcv_saddr(sk);
68 struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
69
70 if (l2tp == NULL)
71 continue;
72
73 if ((l2tp->conn_id == tunnel_id) &&
74 net_eq(sock_net(sk), net) &&
75 !(addr && ipv6_addr_equal(addr, laddr)) &&
76 !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
77 goto found;
78 }
79
80 sk = NULL;
81found:
82 return sk;
83}
84
85static inline struct sock *l2tp_ip6_bind_lookup(struct net *net,
86 struct in6_addr *laddr,
87 int dif, u32 tunnel_id)
88{
89 struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id);
90 if (sk)
91 sock_hold(sk);
92
93 return sk;
94}
95
96/* When processing receive frames, there are two cases to
97 * consider. Data frames consist of a non-zero session-id and an
98 * optional cookie. Control frames consist of a regular L2TP header
99 * preceded by 32-bits of zeros.
100 *
101 * L2TPv3 Session Header Over IP
102 *
103 * 0 1 2 3
104 * 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
105 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
106 * | Session ID |
107 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
108 * | Cookie (optional, maximum 64 bits)...
109 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
110 * |
111 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
112 *
113 * L2TPv3 Control Message Header Over IP
114 *
115 * 0 1 2 3
116 * 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
117 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
118 * | (32 bits of zeros) |
119 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
120 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
121 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
122 * | Control Connection ID |
123 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
124 * | Ns | Nr |
125 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
126 *
127 * All control frames are passed to userspace.
128 */
129static int l2tp_ip6_recv(struct sk_buff *skb)
130{
131 struct sock *sk;
132 u32 session_id;
133 u32 tunnel_id;
134 unsigned char *ptr, *optr;
135 struct l2tp_session *session;
136 struct l2tp_tunnel *tunnel = NULL;
137 int length;
138
139 /* Point to L2TP header */
140 optr = ptr = skb->data;
141
142 if (!pskb_may_pull(skb, 4))
143 goto discard;
144
145 session_id = ntohl(*((__be32 *) ptr));
146 ptr += 4;
147
148 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
149 * the session_id. If it is 0, the packet is a L2TP control
150 * frame and the session_id value can be discarded.
151 */
152 if (session_id == 0) {
153 __skb_pull(skb, 4);
154 goto pass_up;
155 }
156
157 /* Ok, this is a data packet. Lookup the session. */
158 session = l2tp_session_find(&init_net, NULL, session_id);
159 if (session == NULL)
160 goto discard;
161
162 tunnel = session->tunnel;
163 if (tunnel == NULL)
164 goto discard;
165
166 /* Trace packet contents, if enabled */
167 if (tunnel->debug & L2TP_MSG_DATA) {
168 length = min(32u, skb->len);
169 if (!pskb_may_pull(skb, length))
170 goto discard;
171
172 pr_debug("%s: ip recv\n", tunnel->name);
173 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
174 }
175
176 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
177 tunnel->recv_payload_hook);
178 return 0;
179
180pass_up:
181 /* Get the tunnel_id from the L2TP header */
182 if (!pskb_may_pull(skb, 12))
183 goto discard;
184
185 if ((skb->data[0] & 0xc0) != 0xc0)
186 goto discard;
187
188 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
189 tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
190 if (tunnel != NULL)
191 sk = tunnel->sock;
192 else {
193 struct ipv6hdr *iph = ipv6_hdr(skb);
194
195 read_lock_bh(&l2tp_ip6_lock);
196 sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr,
197 0, tunnel_id);
198 read_unlock_bh(&l2tp_ip6_lock);
199 }
200
201 if (sk == NULL)
202 goto discard;
203
204 sock_hold(sk);
205
206 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
207 goto discard_put;
208
209 nf_reset(skb);
210
211 return sk_receive_skb(sk, skb, 1);
212
213discard_put:
214 sock_put(sk);
215
216discard:
217 kfree_skb(skb);
218 return 0;
219}
220
221static int l2tp_ip6_open(struct sock *sk)
222{
223 /* Prevent autobind. We don't have ports. */
224 inet_sk(sk)->inet_num = IPPROTO_L2TP;
225
226 write_lock_bh(&l2tp_ip6_lock);
227 sk_add_node(sk, &l2tp_ip6_table);
228 write_unlock_bh(&l2tp_ip6_lock);
229
230 return 0;
231}
232
233static void l2tp_ip6_close(struct sock *sk, long timeout)
234{
235 write_lock_bh(&l2tp_ip6_lock);
236 hlist_del_init(&sk->sk_bind_node);
237 sk_del_node_init(sk);
238 write_unlock_bh(&l2tp_ip6_lock);
239
240 sk_common_release(sk);
241}
242
243static void l2tp_ip6_destroy_sock(struct sock *sk)
244{
245 lock_sock(sk);
246 ip6_flush_pending_frames(sk);
247 release_sock(sk);
248
249 inet6_destroy_sock(sk);
250}
251
252static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
253{
254 struct inet_sock *inet = inet_sk(sk);
255 struct ipv6_pinfo *np = inet6_sk(sk);
256 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
257 __be32 v4addr = 0;
258 int addr_type;
259 int err;
260
261 if (!sock_flag(sk, SOCK_ZAPPED))
262 return -EINVAL;
263 if (addr->l2tp_family != AF_INET6)
264 return -EINVAL;
265 if (addr_len < sizeof(*addr))
266 return -EINVAL;
267
268 addr_type = ipv6_addr_type(&addr->l2tp_addr);
269
270 /* l2tp_ip6 sockets are IPv6 only */
271 if (addr_type == IPV6_ADDR_MAPPED)
272 return -EADDRNOTAVAIL;
273
274 /* L2TP is point-point, not multicast */
275 if (addr_type & IPV6_ADDR_MULTICAST)
276 return -EADDRNOTAVAIL;
277
278 err = -EADDRINUSE;
279 read_lock_bh(&l2tp_ip6_lock);
280 if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr,
281 sk->sk_bound_dev_if, addr->l2tp_conn_id))
282 goto out_in_use;
283 read_unlock_bh(&l2tp_ip6_lock);
284
285 lock_sock(sk);
286
287 err = -EINVAL;
288 if (sk->sk_state != TCP_CLOSE)
289 goto out_unlock;
290
291 /* Check if the address belongs to the host. */
292 rcu_read_lock();
293 if (addr_type != IPV6_ADDR_ANY) {
294 struct net_device *dev = NULL;
295
296 if (addr_type & IPV6_ADDR_LINKLOCAL) {
297 if (addr_len >= sizeof(struct sockaddr_in6) &&
298 addr->l2tp_scope_id) {
299 /* Override any existing binding, if another
300 * one is supplied by user.
301 */
302 sk->sk_bound_dev_if = addr->l2tp_scope_id;
303 }
304
305 /* Binding to link-local address requires an
306 interface */
307 if (!sk->sk_bound_dev_if)
308 goto out_unlock_rcu;
309
310 err = -ENODEV;
311 dev = dev_get_by_index_rcu(sock_net(sk),
312 sk->sk_bound_dev_if);
313 if (!dev)
314 goto out_unlock_rcu;
315 }
316
317 /* ipv4 addr of the socket is invalid. Only the
318 * unspecified and mapped address have a v4 equivalent.
319 */
320 v4addr = LOOPBACK4_IPV6;
321 err = -EADDRNOTAVAIL;
322 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
323 goto out_unlock_rcu;
324 }
325 rcu_read_unlock();
326
327 inet->inet_rcv_saddr = inet->inet_saddr = v4addr;
328 np->rcv_saddr = addr->l2tp_addr;
329 np->saddr = addr->l2tp_addr;
330
331 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
332
333 write_lock_bh(&l2tp_ip6_lock);
334 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
335 sk_del_node_init(sk);
336 write_unlock_bh(&l2tp_ip6_lock);
337
338 sock_reset_flag(sk, SOCK_ZAPPED);
339 release_sock(sk);
340 return 0;
341
342out_unlock_rcu:
343 rcu_read_unlock();
344out_unlock:
345 release_sock(sk);
346 return err;
347
348out_in_use:
349 read_unlock_bh(&l2tp_ip6_lock);
350 return err;
351}
352
353static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
354 int addr_len)
355{
356 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
357 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
358 struct in6_addr *daddr;
359 int addr_type;
360 int rc;
361
362 if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
363 return -EINVAL;
364
365 if (addr_len < sizeof(*lsa))
366 return -EINVAL;
367
368 addr_type = ipv6_addr_type(&usin->sin6_addr);
369 if (addr_type & IPV6_ADDR_MULTICAST)
370 return -EINVAL;
371
372 if (addr_type & IPV6_ADDR_MAPPED) {
373 daddr = &usin->sin6_addr;
374 if (ipv4_is_multicast(daddr->s6_addr32[3]))
375 return -EINVAL;
376 }
377
378 rc = ip6_datagram_connect(sk, uaddr, addr_len);
379
380 lock_sock(sk);
381
382 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
383
384 write_lock_bh(&l2tp_ip6_lock);
385 hlist_del_init(&sk->sk_bind_node);
386 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
387 write_unlock_bh(&l2tp_ip6_lock);
388
389 release_sock(sk);
390
391 return rc;
392}
393
394static int l2tp_ip6_disconnect(struct sock *sk, int flags)
395{
396 if (sock_flag(sk, SOCK_ZAPPED))
397 return 0;
398
399 return udp_disconnect(sk, flags);
400}
401
402static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
403 int *uaddr_len, int peer)
404{
405 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
406 struct sock *sk = sock->sk;
407 struct ipv6_pinfo *np = inet6_sk(sk);
408 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
409
410 lsa->l2tp_family = AF_INET6;
411 lsa->l2tp_flowinfo = 0;
412 lsa->l2tp_scope_id = 0;
413 lsa->l2tp_unused = 0;
414 if (peer) {
415 if (!lsk->peer_conn_id)
416 return -ENOTCONN;
417 lsa->l2tp_conn_id = lsk->peer_conn_id;
418 lsa->l2tp_addr = np->daddr;
419 if (np->sndflow)
420 lsa->l2tp_flowinfo = np->flow_label;
421 } else {
422 if (ipv6_addr_any(&np->rcv_saddr))
423 lsa->l2tp_addr = np->saddr;
424 else
425 lsa->l2tp_addr = np->rcv_saddr;
426
427 lsa->l2tp_conn_id = lsk->conn_id;
428 }
429 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
430 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
431 *uaddr_len = sizeof(*lsa);
432 return 0;
433}
434
435static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
436{
437 int rc;
438
439 /* Charge it to the socket, dropping if the queue is full. */
440 rc = sock_queue_rcv_skb(sk, skb);
441 if (rc < 0)
442 goto drop;
443
444 return 0;
445
446drop:
447 IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
448 kfree_skb(skb);
449 return -1;
450}
451
452static int l2tp_ip6_push_pending_frames(struct sock *sk)
453{
454 struct sk_buff *skb;
455 __be32 *transhdr = NULL;
456 int err = 0;
457
458 skb = skb_peek(&sk->sk_write_queue);
459 if (skb == NULL)
460 goto out;
461
462 transhdr = (__be32 *)skb_transport_header(skb);
463 *transhdr = 0;
464
465 err = ip6_push_pending_frames(sk);
466
467out:
468 return err;
469}
470
471/* Userspace will call sendmsg() on the tunnel socket to send L2TP
472 * control frames.
473 */
474static int l2tp_ip6_sendmsg(struct kiocb *iocb, struct sock *sk,
475 struct msghdr *msg, size_t len)
476{
477 struct ipv6_txoptions opt_space;
478 struct sockaddr_l2tpip6 *lsa =
479 (struct sockaddr_l2tpip6 *) msg->msg_name;
480 struct in6_addr *daddr, *final_p, final;
481 struct ipv6_pinfo *np = inet6_sk(sk);
482 struct ipv6_txoptions *opt = NULL;
483 struct ip6_flowlabel *flowlabel = NULL;
484 struct dst_entry *dst = NULL;
485 struct flowi6 fl6;
486 int addr_len = msg->msg_namelen;
487 int hlimit = -1;
488 int tclass = -1;
489 int dontfrag = -1;
490 int transhdrlen = 4; /* zero session-id */
491 int ulen = len + transhdrlen;
492 int err;
493
494 /* Rough check on arithmetic overflow,
495 better check is made in ip6_append_data().
496 */
497 if (len > INT_MAX)
498 return -EMSGSIZE;
499
500 /* Mirror BSD error message compatibility */
501 if (msg->msg_flags & MSG_OOB)
502 return -EOPNOTSUPP;
503
504 /*
505 * Get and verify the address.
506 */
507 memset(&fl6, 0, sizeof(fl6));
508
509 fl6.flowi6_mark = sk->sk_mark;
510
511 if (lsa) {
512 if (addr_len < SIN6_LEN_RFC2133)
513 return -EINVAL;
514
515 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
516 return -EAFNOSUPPORT;
517
518 daddr = &lsa->l2tp_addr;
519 if (np->sndflow) {
520 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
521 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
522 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
523 if (flowlabel == NULL)
524 return -EINVAL;
525 daddr = &flowlabel->dst;
526 }
527 }
528
529 /*
530 * Otherwise it will be difficult to maintain
531 * sk->sk_dst_cache.
532 */
533 if (sk->sk_state == TCP_ESTABLISHED &&
534 ipv6_addr_equal(daddr, &np->daddr))
535 daddr = &np->daddr;
536
537 if (addr_len >= sizeof(struct sockaddr_in6) &&
538 lsa->l2tp_scope_id &&
539 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
540 fl6.flowi6_oif = lsa->l2tp_scope_id;
541 } else {
542 if (sk->sk_state != TCP_ESTABLISHED)
543 return -EDESTADDRREQ;
544
545 daddr = &np->daddr;
546 fl6.flowlabel = np->flow_label;
547 }
548
549 if (fl6.flowi6_oif == 0)
550 fl6.flowi6_oif = sk->sk_bound_dev_if;
551
552 if (msg->msg_controllen) {
553 opt = &opt_space;
554 memset(opt, 0, sizeof(struct ipv6_txoptions));
555 opt->tot_len = sizeof(struct ipv6_txoptions);
556
557 err = datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
558 &hlimit, &tclass, &dontfrag);
559 if (err < 0) {
560 fl6_sock_release(flowlabel);
561 return err;
562 }
563 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
564 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
565 if (flowlabel == NULL)
566 return -EINVAL;
567 }
568 if (!(opt->opt_nflen|opt->opt_flen))
569 opt = NULL;
570 }
571
572 if (opt == NULL)
573 opt = np->opt;
574 if (flowlabel)
575 opt = fl6_merge_options(&opt_space, flowlabel, opt);
576 opt = ipv6_fixup_options(&opt_space, opt);
577
578 fl6.flowi6_proto = sk->sk_protocol;
579 if (!ipv6_addr_any(daddr))
580 fl6.daddr = *daddr;
581 else
582 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
583 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
584 fl6.saddr = np->saddr;
585
586 final_p = fl6_update_dst(&fl6, opt, &final);
587
588 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
589 fl6.flowi6_oif = np->mcast_oif;
590 else if (!fl6.flowi6_oif)
591 fl6.flowi6_oif = np->ucast_oif;
592
593 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
594
595 dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
596 if (IS_ERR(dst)) {
597 err = PTR_ERR(dst);
598 goto out;
599 }
600
601 if (hlimit < 0) {
602 if (ipv6_addr_is_multicast(&fl6.daddr))
603 hlimit = np->mcast_hops;
604 else
605 hlimit = np->hop_limit;
606 if (hlimit < 0)
607 hlimit = ip6_dst_hoplimit(dst);
608 }
609
610 if (tclass < 0)
611 tclass = np->tclass;
612
613 if (dontfrag < 0)
614 dontfrag = np->dontfrag;
615
616 if (msg->msg_flags & MSG_CONFIRM)
617 goto do_confirm;
618
619back_from_confirm:
620 lock_sock(sk);
621 err = ip6_append_data(sk, ip_generic_getfrag, msg->msg_iov,
622 ulen, transhdrlen, hlimit, tclass, opt,
623 &fl6, (struct rt6_info *)dst,
624 msg->msg_flags, dontfrag);
625 if (err)
626 ip6_flush_pending_frames(sk);
627 else if (!(msg->msg_flags & MSG_MORE))
628 err = l2tp_ip6_push_pending_frames(sk);
629 release_sock(sk);
630done:
631 dst_release(dst);
632out:
633 fl6_sock_release(flowlabel);
634
635 return err < 0 ? err : len;
636
637do_confirm:
638 dst_confirm(dst);
639 if (!(msg->msg_flags & MSG_PROBE) || len)
640 goto back_from_confirm;
641 err = 0;
642 goto done;
643}
644
645static int l2tp_ip6_recvmsg(struct kiocb *iocb, struct sock *sk,
646 struct msghdr *msg, size_t len, int noblock,
647 int flags, int *addr_len)
648{
649 struct inet_sock *inet = inet_sk(sk);
650 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)msg->msg_name;
651 size_t copied = 0;
652 int err = -EOPNOTSUPP;
653 struct sk_buff *skb;
654
655 if (flags & MSG_OOB)
656 goto out;
657
658 if (addr_len)
659 *addr_len = sizeof(*lsa);
660
661 if (flags & MSG_ERRQUEUE)
662 return ipv6_recv_error(sk, msg, len);
663
664 skb = skb_recv_datagram(sk, flags, noblock, &err);
665 if (!skb)
666 goto out;
667
668 copied = skb->len;
669 if (len < copied) {
670 msg->msg_flags |= MSG_TRUNC;
671 copied = len;
672 }
673
674 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
675 if (err)
676 goto done;
677
678 sock_recv_timestamp(msg, sk, skb);
679
680 /* Copy the address. */
681 if (lsa) {
682 lsa->l2tp_family = AF_INET6;
683 lsa->l2tp_unused = 0;
684 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
685 lsa->l2tp_flowinfo = 0;
686 lsa->l2tp_scope_id = 0;
687 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
688 lsa->l2tp_scope_id = IP6CB(skb)->iif;
689 }
690
691 if (inet->cmsg_flags)
692 ip_cmsg_recv(msg, skb);
693
694 if (flags & MSG_TRUNC)
695 copied = skb->len;
696done:
697 skb_free_datagram(sk, skb);
698out:
699 return err ? err : copied;
700}
701
702static struct proto l2tp_ip6_prot = {
703 .name = "L2TP/IPv6",
704 .owner = THIS_MODULE,
705 .init = l2tp_ip6_open,
706 .close = l2tp_ip6_close,
707 .bind = l2tp_ip6_bind,
708 .connect = l2tp_ip6_connect,
709 .disconnect = l2tp_ip6_disconnect,
710 .ioctl = udp_ioctl,
711 .destroy = l2tp_ip6_destroy_sock,
712 .setsockopt = ipv6_setsockopt,
713 .getsockopt = ipv6_getsockopt,
714 .sendmsg = l2tp_ip6_sendmsg,
715 .recvmsg = l2tp_ip6_recvmsg,
716 .backlog_rcv = l2tp_ip6_backlog_recv,
717 .hash = inet_hash,
718 .unhash = inet_unhash,
719 .obj_size = sizeof(struct l2tp_ip6_sock),
720#ifdef CONFIG_COMPAT
721 .compat_setsockopt = compat_ipv6_setsockopt,
722 .compat_getsockopt = compat_ipv6_getsockopt,
723#endif
724};
725
726static const struct proto_ops l2tp_ip6_ops = {
727 .family = PF_INET6,
728 .owner = THIS_MODULE,
729 .release = inet6_release,
730 .bind = inet6_bind,
731 .connect = inet_dgram_connect,
732 .socketpair = sock_no_socketpair,
733 .accept = sock_no_accept,
734 .getname = l2tp_ip6_getname,
735 .poll = datagram_poll,
736 .ioctl = inet6_ioctl,
737 .listen = sock_no_listen,
738 .shutdown = inet_shutdown,
739 .setsockopt = sock_common_setsockopt,
740 .getsockopt = sock_common_getsockopt,
741 .sendmsg = inet_sendmsg,
742 .recvmsg = sock_common_recvmsg,
743 .mmap = sock_no_mmap,
744 .sendpage = sock_no_sendpage,
745#ifdef CONFIG_COMPAT
746 .compat_setsockopt = compat_sock_common_setsockopt,
747 .compat_getsockopt = compat_sock_common_getsockopt,
748#endif
749};
750
751static struct inet_protosw l2tp_ip6_protosw = {
752 .type = SOCK_DGRAM,
753 .protocol = IPPROTO_L2TP,
754 .prot = &l2tp_ip6_prot,
755 .ops = &l2tp_ip6_ops,
756 .no_check = 0,
757};
758
759static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
760 .handler = l2tp_ip6_recv,
761};
762
763static int __init l2tp_ip6_init(void)
764{
765 int err;
766
767 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
768
769 err = proto_register(&l2tp_ip6_prot, 1);
770 if (err != 0)
771 goto out;
772
773 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
774 if (err)
775 goto out1;
776
777 inet6_register_protosw(&l2tp_ip6_protosw);
778 return 0;
779
780out1:
781 proto_unregister(&l2tp_ip6_prot);
782out:
783 return err;
784}
785
786static void __exit l2tp_ip6_exit(void)
787{
788 inet6_unregister_protosw(&l2tp_ip6_protosw);
789 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
790 proto_unregister(&l2tp_ip6_prot);
791}
792
793module_init(l2tp_ip6_init);
794module_exit(l2tp_ip6_exit);
795
796MODULE_LICENSE("GPL");
797MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
798MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
799MODULE_VERSION("1.0");
800
801/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
802 * enums
803 */
804MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * L2TPv3 IP encapsulation support for IPv6
4 *
5 * Copyright (c) 2012 Katalix Systems Ltd
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/icmp.h>
11#include <linux/module.h>
12#include <linux/skbuff.h>
13#include <linux/random.h>
14#include <linux/socket.h>
15#include <linux/l2tp.h>
16#include <linux/in.h>
17#include <linux/in6.h>
18#include <net/sock.h>
19#include <net/ip.h>
20#include <net/icmp.h>
21#include <net/udp.h>
22#include <net/inet_common.h>
23#include <net/inet_hashtables.h>
24#include <net/inet6_hashtables.h>
25#include <net/tcp_states.h>
26#include <net/protocol.h>
27#include <net/xfrm.h>
28
29#include <net/transp_v6.h>
30#include <net/addrconf.h>
31#include <net/ip6_route.h>
32
33#include "l2tp_core.h"
34
35struct l2tp_ip6_sock {
36 /* inet_sock has to be the first member of l2tp_ip6_sock */
37 struct inet_sock inet;
38
39 u32 conn_id;
40 u32 peer_conn_id;
41
42 /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
43 inet6_sk_generic */
44 struct ipv6_pinfo inet6;
45};
46
47static DEFINE_RWLOCK(l2tp_ip6_lock);
48static struct hlist_head l2tp_ip6_table;
49static struct hlist_head l2tp_ip6_bind_table;
50
51static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
52{
53 return (struct l2tp_ip6_sock *)sk;
54}
55
56static struct sock *__l2tp_ip6_bind_lookup(const struct net *net,
57 const struct in6_addr *laddr,
58 const struct in6_addr *raddr,
59 int dif, u32 tunnel_id)
60{
61 struct sock *sk;
62
63 sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
64 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
65 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr;
66 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
67
68 if (!net_eq(sock_net(sk), net))
69 continue;
70
71 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
72 continue;
73
74 if (sk_laddr && !ipv6_addr_any(sk_laddr) &&
75 !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr))
76 continue;
77
78 if (!ipv6_addr_any(sk_raddr) && raddr &&
79 !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr))
80 continue;
81
82 if (l2tp->conn_id != tunnel_id)
83 continue;
84
85 goto found;
86 }
87
88 sk = NULL;
89found:
90 return sk;
91}
92
93/* When processing receive frames, there are two cases to
94 * consider. Data frames consist of a non-zero session-id and an
95 * optional cookie. Control frames consist of a regular L2TP header
96 * preceded by 32-bits of zeros.
97 *
98 * L2TPv3 Session Header Over IP
99 *
100 * 0 1 2 3
101 * 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
102 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
103 * | Session ID |
104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
105 * | Cookie (optional, maximum 64 bits)...
106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
107 * |
108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
109 *
110 * L2TPv3 Control Message Header Over IP
111 *
112 * 0 1 2 3
113 * 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
114 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
115 * | (32 bits of zeros) |
116 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
117 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
119 * | Control Connection ID |
120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
121 * | Ns | Nr |
122 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
123 *
124 * All control frames are passed to userspace.
125 */
126static int l2tp_ip6_recv(struct sk_buff *skb)
127{
128 struct net *net = dev_net(skb->dev);
129 struct sock *sk;
130 u32 session_id;
131 u32 tunnel_id;
132 unsigned char *ptr, *optr;
133 struct l2tp_session *session;
134 struct l2tp_tunnel *tunnel = NULL;
135 struct ipv6hdr *iph;
136 int length;
137
138 if (!pskb_may_pull(skb, 4))
139 goto discard;
140
141 /* Point to L2TP header */
142 optr = ptr = skb->data;
143 session_id = ntohl(*((__be32 *) ptr));
144 ptr += 4;
145
146 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
147 * the session_id. If it is 0, the packet is a L2TP control
148 * frame and the session_id value can be discarded.
149 */
150 if (session_id == 0) {
151 __skb_pull(skb, 4);
152 goto pass_up;
153 }
154
155 /* Ok, this is a data packet. Lookup the session. */
156 session = l2tp_session_get(net, session_id);
157 if (!session)
158 goto discard;
159
160 tunnel = session->tunnel;
161 if (!tunnel)
162 goto discard_sess;
163
164 /* Trace packet contents, if enabled */
165 if (tunnel->debug & L2TP_MSG_DATA) {
166 length = min(32u, skb->len);
167 if (!pskb_may_pull(skb, length))
168 goto discard_sess;
169
170 /* Point to L2TP header */
171 optr = ptr = skb->data;
172 ptr += 4;
173 pr_debug("%s: ip recv\n", tunnel->name);
174 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
175 }
176
177 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
178 goto discard_sess;
179
180 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
181 l2tp_session_dec_refcount(session);
182
183 return 0;
184
185pass_up:
186 /* Get the tunnel_id from the L2TP header */
187 if (!pskb_may_pull(skb, 12))
188 goto discard;
189
190 if ((skb->data[0] & 0xc0) != 0xc0)
191 goto discard;
192
193 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
194 iph = ipv6_hdr(skb);
195
196 read_lock_bh(&l2tp_ip6_lock);
197 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
198 inet6_iif(skb), tunnel_id);
199 if (!sk) {
200 read_unlock_bh(&l2tp_ip6_lock);
201 goto discard;
202 }
203 sock_hold(sk);
204 read_unlock_bh(&l2tp_ip6_lock);
205
206 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
207 goto discard_put;
208
209 nf_reset_ct(skb);
210
211 return sk_receive_skb(sk, skb, 1);
212
213discard_sess:
214 l2tp_session_dec_refcount(session);
215 goto discard;
216
217discard_put:
218 sock_put(sk);
219
220discard:
221 kfree_skb(skb);
222 return 0;
223}
224
225static int l2tp_ip6_open(struct sock *sk)
226{
227 /* Prevent autobind. We don't have ports. */
228 inet_sk(sk)->inet_num = IPPROTO_L2TP;
229
230 write_lock_bh(&l2tp_ip6_lock);
231 sk_add_node(sk, &l2tp_ip6_table);
232 write_unlock_bh(&l2tp_ip6_lock);
233
234 return 0;
235}
236
237static void l2tp_ip6_close(struct sock *sk, long timeout)
238{
239 write_lock_bh(&l2tp_ip6_lock);
240 hlist_del_init(&sk->sk_bind_node);
241 sk_del_node_init(sk);
242 write_unlock_bh(&l2tp_ip6_lock);
243
244 sk_common_release(sk);
245}
246
247static void l2tp_ip6_destroy_sock(struct sock *sk)
248{
249 struct l2tp_tunnel *tunnel = sk->sk_user_data;
250
251 lock_sock(sk);
252 ip6_flush_pending_frames(sk);
253 release_sock(sk);
254
255 if (tunnel)
256 l2tp_tunnel_delete(tunnel);
257
258 inet6_destroy_sock(sk);
259}
260
261static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
262{
263 struct inet_sock *inet = inet_sk(sk);
264 struct ipv6_pinfo *np = inet6_sk(sk);
265 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
266 struct net *net = sock_net(sk);
267 __be32 v4addr = 0;
268 int bound_dev_if;
269 int addr_type;
270 int err;
271
272 if (addr->l2tp_family != AF_INET6)
273 return -EINVAL;
274 if (addr_len < sizeof(*addr))
275 return -EINVAL;
276
277 addr_type = ipv6_addr_type(&addr->l2tp_addr);
278
279 /* l2tp_ip6 sockets are IPv6 only */
280 if (addr_type == IPV6_ADDR_MAPPED)
281 return -EADDRNOTAVAIL;
282
283 /* L2TP is point-point, not multicast */
284 if (addr_type & IPV6_ADDR_MULTICAST)
285 return -EADDRNOTAVAIL;
286
287 lock_sock(sk);
288
289 err = -EINVAL;
290 if (!sock_flag(sk, SOCK_ZAPPED))
291 goto out_unlock;
292
293 if (sk->sk_state != TCP_CLOSE)
294 goto out_unlock;
295
296 bound_dev_if = sk->sk_bound_dev_if;
297
298 /* Check if the address belongs to the host. */
299 rcu_read_lock();
300 if (addr_type != IPV6_ADDR_ANY) {
301 struct net_device *dev = NULL;
302
303 if (addr_type & IPV6_ADDR_LINKLOCAL) {
304 if (addr->l2tp_scope_id)
305 bound_dev_if = addr->l2tp_scope_id;
306
307 /* Binding to link-local address requires an
308 * interface.
309 */
310 if (!bound_dev_if)
311 goto out_unlock_rcu;
312
313 err = -ENODEV;
314 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
315 if (!dev)
316 goto out_unlock_rcu;
317 }
318
319 /* ipv4 addr of the socket is invalid. Only the
320 * unspecified and mapped address have a v4 equivalent.
321 */
322 v4addr = LOOPBACK4_IPV6;
323 err = -EADDRNOTAVAIL;
324 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
325 goto out_unlock_rcu;
326 }
327 rcu_read_unlock();
328
329 write_lock_bh(&l2tp_ip6_lock);
330 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
331 addr->l2tp_conn_id)) {
332 write_unlock_bh(&l2tp_ip6_lock);
333 err = -EADDRINUSE;
334 goto out_unlock;
335 }
336
337 inet->inet_saddr = v4addr;
338 inet->inet_rcv_saddr = v4addr;
339 sk->sk_bound_dev_if = bound_dev_if;
340 sk->sk_v6_rcv_saddr = addr->l2tp_addr;
341 np->saddr = addr->l2tp_addr;
342
343 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
344
345 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
346 sk_del_node_init(sk);
347 write_unlock_bh(&l2tp_ip6_lock);
348
349 sock_reset_flag(sk, SOCK_ZAPPED);
350 release_sock(sk);
351 return 0;
352
353out_unlock_rcu:
354 rcu_read_unlock();
355out_unlock:
356 release_sock(sk);
357
358 return err;
359}
360
361static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
362 int addr_len)
363{
364 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
365 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
366 struct in6_addr *daddr;
367 int addr_type;
368 int rc;
369
370 if (addr_len < sizeof(*lsa))
371 return -EINVAL;
372
373 if (usin->sin6_family != AF_INET6)
374 return -EINVAL;
375
376 addr_type = ipv6_addr_type(&usin->sin6_addr);
377 if (addr_type & IPV6_ADDR_MULTICAST)
378 return -EINVAL;
379
380 if (addr_type & IPV6_ADDR_MAPPED) {
381 daddr = &usin->sin6_addr;
382 if (ipv4_is_multicast(daddr->s6_addr32[3]))
383 return -EINVAL;
384 }
385
386 lock_sock(sk);
387
388 /* Must bind first - autobinding does not work */
389 if (sock_flag(sk, SOCK_ZAPPED)) {
390 rc = -EINVAL;
391 goto out_sk;
392 }
393
394 rc = __ip6_datagram_connect(sk, uaddr, addr_len);
395 if (rc < 0)
396 goto out_sk;
397
398 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
399
400 write_lock_bh(&l2tp_ip6_lock);
401 hlist_del_init(&sk->sk_bind_node);
402 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
403 write_unlock_bh(&l2tp_ip6_lock);
404
405out_sk:
406 release_sock(sk);
407
408 return rc;
409}
410
411static int l2tp_ip6_disconnect(struct sock *sk, int flags)
412{
413 if (sock_flag(sk, SOCK_ZAPPED))
414 return 0;
415
416 return __udp_disconnect(sk, flags);
417}
418
419static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
420 int peer)
421{
422 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
423 struct sock *sk = sock->sk;
424 struct ipv6_pinfo *np = inet6_sk(sk);
425 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
426
427 lsa->l2tp_family = AF_INET6;
428 lsa->l2tp_flowinfo = 0;
429 lsa->l2tp_scope_id = 0;
430 lsa->l2tp_unused = 0;
431 if (peer) {
432 if (!lsk->peer_conn_id)
433 return -ENOTCONN;
434 lsa->l2tp_conn_id = lsk->peer_conn_id;
435 lsa->l2tp_addr = sk->sk_v6_daddr;
436 if (np->sndflow)
437 lsa->l2tp_flowinfo = np->flow_label;
438 } else {
439 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
440 lsa->l2tp_addr = np->saddr;
441 else
442 lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
443
444 lsa->l2tp_conn_id = lsk->conn_id;
445 }
446 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
447 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
448 return sizeof(*lsa);
449}
450
451static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
452{
453 int rc;
454
455 /* Charge it to the socket, dropping if the queue is full. */
456 rc = sock_queue_rcv_skb(sk, skb);
457 if (rc < 0)
458 goto drop;
459
460 return 0;
461
462drop:
463 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
464 kfree_skb(skb);
465 return -1;
466}
467
468static int l2tp_ip6_push_pending_frames(struct sock *sk)
469{
470 struct sk_buff *skb;
471 __be32 *transhdr = NULL;
472 int err = 0;
473
474 skb = skb_peek(&sk->sk_write_queue);
475 if (skb == NULL)
476 goto out;
477
478 transhdr = (__be32 *)skb_transport_header(skb);
479 *transhdr = 0;
480
481 err = ip6_push_pending_frames(sk);
482
483out:
484 return err;
485}
486
487/* Userspace will call sendmsg() on the tunnel socket to send L2TP
488 * control frames.
489 */
490static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
491{
492 struct ipv6_txoptions opt_space;
493 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
494 struct in6_addr *daddr, *final_p, final;
495 struct ipv6_pinfo *np = inet6_sk(sk);
496 struct ipv6_txoptions *opt_to_free = NULL;
497 struct ipv6_txoptions *opt = NULL;
498 struct ip6_flowlabel *flowlabel = NULL;
499 struct dst_entry *dst = NULL;
500 struct flowi6 fl6;
501 struct ipcm6_cookie ipc6;
502 int addr_len = msg->msg_namelen;
503 int transhdrlen = 4; /* zero session-id */
504 int ulen = len + transhdrlen;
505 int err;
506
507 /* Rough check on arithmetic overflow,
508 better check is made in ip6_append_data().
509 */
510 if (len > INT_MAX)
511 return -EMSGSIZE;
512
513 /* Mirror BSD error message compatibility */
514 if (msg->msg_flags & MSG_OOB)
515 return -EOPNOTSUPP;
516
517 /*
518 * Get and verify the address.
519 */
520 memset(&fl6, 0, sizeof(fl6));
521
522 fl6.flowi6_mark = sk->sk_mark;
523 fl6.flowi6_uid = sk->sk_uid;
524
525 ipcm6_init(&ipc6);
526
527 if (lsa) {
528 if (addr_len < SIN6_LEN_RFC2133)
529 return -EINVAL;
530
531 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
532 return -EAFNOSUPPORT;
533
534 daddr = &lsa->l2tp_addr;
535 if (np->sndflow) {
536 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
537 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
538 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
539 if (IS_ERR(flowlabel))
540 return -EINVAL;
541 }
542 }
543
544 /*
545 * Otherwise it will be difficult to maintain
546 * sk->sk_dst_cache.
547 */
548 if (sk->sk_state == TCP_ESTABLISHED &&
549 ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
550 daddr = &sk->sk_v6_daddr;
551
552 if (addr_len >= sizeof(struct sockaddr_in6) &&
553 lsa->l2tp_scope_id &&
554 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
555 fl6.flowi6_oif = lsa->l2tp_scope_id;
556 } else {
557 if (sk->sk_state != TCP_ESTABLISHED)
558 return -EDESTADDRREQ;
559
560 daddr = &sk->sk_v6_daddr;
561 fl6.flowlabel = np->flow_label;
562 }
563
564 if (fl6.flowi6_oif == 0)
565 fl6.flowi6_oif = sk->sk_bound_dev_if;
566
567 if (msg->msg_controllen) {
568 opt = &opt_space;
569 memset(opt, 0, sizeof(struct ipv6_txoptions));
570 opt->tot_len = sizeof(struct ipv6_txoptions);
571 ipc6.opt = opt;
572
573 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6);
574 if (err < 0) {
575 fl6_sock_release(flowlabel);
576 return err;
577 }
578 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
579 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
580 if (IS_ERR(flowlabel))
581 return -EINVAL;
582 }
583 if (!(opt->opt_nflen|opt->opt_flen))
584 opt = NULL;
585 }
586
587 if (!opt) {
588 opt = txopt_get(np);
589 opt_to_free = opt;
590 }
591 if (flowlabel)
592 opt = fl6_merge_options(&opt_space, flowlabel, opt);
593 opt = ipv6_fixup_options(&opt_space, opt);
594 ipc6.opt = opt;
595
596 fl6.flowi6_proto = sk->sk_protocol;
597 if (!ipv6_addr_any(daddr))
598 fl6.daddr = *daddr;
599 else
600 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
601 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
602 fl6.saddr = np->saddr;
603
604 final_p = fl6_update_dst(&fl6, opt, &final);
605
606 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
607 fl6.flowi6_oif = np->mcast_oif;
608 else if (!fl6.flowi6_oif)
609 fl6.flowi6_oif = np->ucast_oif;
610
611 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
612
613 if (ipc6.tclass < 0)
614 ipc6.tclass = np->tclass;
615
616 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
617
618 dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
619 if (IS_ERR(dst)) {
620 err = PTR_ERR(dst);
621 goto out;
622 }
623
624 if (ipc6.hlimit < 0)
625 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
626
627 if (ipc6.dontfrag < 0)
628 ipc6.dontfrag = np->dontfrag;
629
630 if (msg->msg_flags & MSG_CONFIRM)
631 goto do_confirm;
632
633back_from_confirm:
634 lock_sock(sk);
635 err = ip6_append_data(sk, ip_generic_getfrag, msg,
636 ulen, transhdrlen, &ipc6,
637 &fl6, (struct rt6_info *)dst,
638 msg->msg_flags);
639 if (err)
640 ip6_flush_pending_frames(sk);
641 else if (!(msg->msg_flags & MSG_MORE))
642 err = l2tp_ip6_push_pending_frames(sk);
643 release_sock(sk);
644done:
645 dst_release(dst);
646out:
647 fl6_sock_release(flowlabel);
648 txopt_put(opt_to_free);
649
650 return err < 0 ? err : len;
651
652do_confirm:
653 if (msg->msg_flags & MSG_PROBE)
654 dst_confirm_neigh(dst, &fl6.daddr);
655 if (!(msg->msg_flags & MSG_PROBE) || len)
656 goto back_from_confirm;
657 err = 0;
658 goto done;
659}
660
661static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
662 int noblock, int flags, int *addr_len)
663{
664 struct ipv6_pinfo *np = inet6_sk(sk);
665 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
666 size_t copied = 0;
667 int err = -EOPNOTSUPP;
668 struct sk_buff *skb;
669
670 if (flags & MSG_OOB)
671 goto out;
672
673 if (flags & MSG_ERRQUEUE)
674 return ipv6_recv_error(sk, msg, len, addr_len);
675
676 skb = skb_recv_datagram(sk, flags, noblock, &err);
677 if (!skb)
678 goto out;
679
680 copied = skb->len;
681 if (len < copied) {
682 msg->msg_flags |= MSG_TRUNC;
683 copied = len;
684 }
685
686 err = skb_copy_datagram_msg(skb, 0, msg, copied);
687 if (err)
688 goto done;
689
690 sock_recv_timestamp(msg, sk, skb);
691
692 /* Copy the address. */
693 if (lsa) {
694 lsa->l2tp_family = AF_INET6;
695 lsa->l2tp_unused = 0;
696 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
697 lsa->l2tp_flowinfo = 0;
698 lsa->l2tp_scope_id = 0;
699 lsa->l2tp_conn_id = 0;
700 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
701 lsa->l2tp_scope_id = inet6_iif(skb);
702 *addr_len = sizeof(*lsa);
703 }
704
705 if (np->rxopt.all)
706 ip6_datagram_recv_ctl(sk, msg, skb);
707
708 if (flags & MSG_TRUNC)
709 copied = skb->len;
710done:
711 skb_free_datagram(sk, skb);
712out:
713 return err ? err : copied;
714}
715
716static struct proto l2tp_ip6_prot = {
717 .name = "L2TP/IPv6",
718 .owner = THIS_MODULE,
719 .init = l2tp_ip6_open,
720 .close = l2tp_ip6_close,
721 .bind = l2tp_ip6_bind,
722 .connect = l2tp_ip6_connect,
723 .disconnect = l2tp_ip6_disconnect,
724 .ioctl = l2tp_ioctl,
725 .destroy = l2tp_ip6_destroy_sock,
726 .setsockopt = ipv6_setsockopt,
727 .getsockopt = ipv6_getsockopt,
728 .sendmsg = l2tp_ip6_sendmsg,
729 .recvmsg = l2tp_ip6_recvmsg,
730 .backlog_rcv = l2tp_ip6_backlog_recv,
731 .hash = inet6_hash,
732 .unhash = inet_unhash,
733 .obj_size = sizeof(struct l2tp_ip6_sock),
734#ifdef CONFIG_COMPAT
735 .compat_setsockopt = compat_ipv6_setsockopt,
736 .compat_getsockopt = compat_ipv6_getsockopt,
737#endif
738};
739
740static const struct proto_ops l2tp_ip6_ops = {
741 .family = PF_INET6,
742 .owner = THIS_MODULE,
743 .release = inet6_release,
744 .bind = inet6_bind,
745 .connect = inet_dgram_connect,
746 .socketpair = sock_no_socketpair,
747 .accept = sock_no_accept,
748 .getname = l2tp_ip6_getname,
749 .poll = datagram_poll,
750 .ioctl = inet6_ioctl,
751 .gettstamp = sock_gettstamp,
752 .listen = sock_no_listen,
753 .shutdown = inet_shutdown,
754 .setsockopt = sock_common_setsockopt,
755 .getsockopt = sock_common_getsockopt,
756 .sendmsg = inet_sendmsg,
757 .recvmsg = sock_common_recvmsg,
758 .mmap = sock_no_mmap,
759 .sendpage = sock_no_sendpage,
760#ifdef CONFIG_COMPAT
761 .compat_setsockopt = compat_sock_common_setsockopt,
762 .compat_getsockopt = compat_sock_common_getsockopt,
763#endif
764};
765
766static struct inet_protosw l2tp_ip6_protosw = {
767 .type = SOCK_DGRAM,
768 .protocol = IPPROTO_L2TP,
769 .prot = &l2tp_ip6_prot,
770 .ops = &l2tp_ip6_ops,
771};
772
773static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
774 .handler = l2tp_ip6_recv,
775};
776
777static int __init l2tp_ip6_init(void)
778{
779 int err;
780
781 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
782
783 err = proto_register(&l2tp_ip6_prot, 1);
784 if (err != 0)
785 goto out;
786
787 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
788 if (err)
789 goto out1;
790
791 inet6_register_protosw(&l2tp_ip6_protosw);
792 return 0;
793
794out1:
795 proto_unregister(&l2tp_ip6_prot);
796out:
797 return err;
798}
799
800static void __exit l2tp_ip6_exit(void)
801{
802 inet6_unregister_protosw(&l2tp_ip6_protosw);
803 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
804 proto_unregister(&l2tp_ip6_prot);
805}
806
807module_init(l2tp_ip6_init);
808module_exit(l2tp_ip6_exit);
809
810MODULE_LICENSE("GPL");
811MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
812MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
813MODULE_VERSION("1.0");
814
815/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
816 * enums
817 */
818MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
819MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);