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
38 struct 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
50 static DEFINE_RWLOCK(l2tp_ip6_lock);
51 static struct hlist_head l2tp_ip6_table;
52 static struct hlist_head l2tp_ip6_bind_table;
53
l2tp_ip6_sk(const struct sock * sk)54 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
55 {
56 return (struct l2tp_ip6_sock *)sk;
57 }
58
__l2tp_ip6_bind_lookup(struct net * net,struct in6_addr * laddr,int dif,u32 tunnel_id)59 static struct sock *__l2tp_ip6_bind_lookup(struct net *net,
60 struct in6_addr *laddr,
61 int dif, u32 tunnel_id)
62 {
63 struct sock *sk;
64
65 sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
66 const struct in6_addr *addr = inet6_rcv_saddr(sk);
67 struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
68
69 if (l2tp == NULL)
70 continue;
71
72 if ((l2tp->conn_id == tunnel_id) &&
73 net_eq(sock_net(sk), net) &&
74 !(addr && ipv6_addr_equal(addr, laddr)) &&
75 !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
76 goto found;
77 }
78
79 sk = NULL;
80 found:
81 return sk;
82 }
83
l2tp_ip6_bind_lookup(struct net * net,struct in6_addr * laddr,int dif,u32 tunnel_id)84 static inline struct sock *l2tp_ip6_bind_lookup(struct net *net,
85 struct in6_addr *laddr,
86 int dif, u32 tunnel_id)
87 {
88 struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id);
89 if (sk)
90 sock_hold(sk);
91
92 return sk;
93 }
94
95 /* When processing receive frames, there are two cases to
96 * consider. Data frames consist of a non-zero session-id and an
97 * optional cookie. Control frames consist of a regular L2TP header
98 * preceded by 32-bits of zeros.
99 *
100 * L2TPv3 Session Header Over IP
101 *
102 * 0 1 2 3
103 * 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
104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
105 * | Session ID |
106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
107 * | Cookie (optional, maximum 64 bits)...
108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
109 * |
110 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
111 *
112 * L2TPv3 Control Message Header Over IP
113 *
114 * 0 1 2 3
115 * 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
116 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
117 * | (32 bits of zeros) |
118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
119 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
121 * | Control Connection ID |
122 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
123 * | Ns | Nr |
124 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
125 *
126 * All control frames are passed to userspace.
127 */
l2tp_ip6_recv(struct sk_buff * skb)128 static int l2tp_ip6_recv(struct sk_buff *skb)
129 {
130 struct sock *sk;
131 u32 session_id;
132 u32 tunnel_id;
133 unsigned char *ptr, *optr;
134 struct l2tp_session *session;
135 struct l2tp_tunnel *tunnel = NULL;
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_find(&init_net, NULL, session_id);
157 if (session == NULL)
158 goto discard;
159
160 tunnel = session->tunnel;
161 if (tunnel == NULL)
162 goto discard;
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;
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 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
178 tunnel->recv_payload_hook);
179 return 0;
180
181 pass_up:
182 /* Get the tunnel_id from the L2TP header */
183 if (!pskb_may_pull(skb, 12))
184 goto discard;
185
186 if ((skb->data[0] & 0xc0) != 0xc0)
187 goto discard;
188
189 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
190 tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
191 if (tunnel != NULL)
192 sk = tunnel->sock;
193 else {
194 struct ipv6hdr *iph = ipv6_hdr(skb);
195
196 read_lock_bh(&l2tp_ip6_lock);
197 sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr,
198 0, tunnel_id);
199 read_unlock_bh(&l2tp_ip6_lock);
200 }
201
202 if (sk == NULL)
203 goto discard;
204
205 sock_hold(sk);
206
207 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
208 goto discard_put;
209
210 nf_reset(skb);
211
212 return sk_receive_skb(sk, skb, 1);
213
214 discard_put:
215 sock_put(sk);
216
217 discard:
218 kfree_skb(skb);
219 return 0;
220 }
221
l2tp_ip6_open(struct sock * sk)222 static int l2tp_ip6_open(struct sock *sk)
223 {
224 /* Prevent autobind. We don't have ports. */
225 inet_sk(sk)->inet_num = IPPROTO_L2TP;
226
227 write_lock_bh(&l2tp_ip6_lock);
228 sk_add_node(sk, &l2tp_ip6_table);
229 write_unlock_bh(&l2tp_ip6_lock);
230
231 return 0;
232 }
233
l2tp_ip6_close(struct sock * sk,long timeout)234 static void l2tp_ip6_close(struct sock *sk, long timeout)
235 {
236 write_lock_bh(&l2tp_ip6_lock);
237 hlist_del_init(&sk->sk_bind_node);
238 sk_del_node_init(sk);
239 write_unlock_bh(&l2tp_ip6_lock);
240
241 sk_common_release(sk);
242 }
243
l2tp_ip6_destroy_sock(struct sock * sk)244 static void l2tp_ip6_destroy_sock(struct sock *sk)
245 {
246 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
247
248 lock_sock(sk);
249 ip6_flush_pending_frames(sk);
250 release_sock(sk);
251
252 if (tunnel) {
253 l2tp_tunnel_closeall(tunnel);
254 sock_put(sk);
255 }
256
257 inet6_destroy_sock(sk);
258 }
259
l2tp_ip6_bind(struct sock * sk,struct sockaddr * uaddr,int addr_len)260 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
261 {
262 struct inet_sock *inet = inet_sk(sk);
263 struct ipv6_pinfo *np = inet6_sk(sk);
264 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
265 __be32 v4addr = 0;
266 int addr_type;
267 int err;
268
269 if (!sock_flag(sk, SOCK_ZAPPED))
270 return -EINVAL;
271 if (addr->l2tp_family != AF_INET6)
272 return -EINVAL;
273 if (addr_len < sizeof(*addr))
274 return -EINVAL;
275
276 addr_type = ipv6_addr_type(&addr->l2tp_addr);
277
278 /* l2tp_ip6 sockets are IPv6 only */
279 if (addr_type == IPV6_ADDR_MAPPED)
280 return -EADDRNOTAVAIL;
281
282 /* L2TP is point-point, not multicast */
283 if (addr_type & IPV6_ADDR_MULTICAST)
284 return -EADDRNOTAVAIL;
285
286 err = -EADDRINUSE;
287 read_lock_bh(&l2tp_ip6_lock);
288 if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr,
289 sk->sk_bound_dev_if, addr->l2tp_conn_id))
290 goto out_in_use;
291 read_unlock_bh(&l2tp_ip6_lock);
292
293 lock_sock(sk);
294
295 err = -EINVAL;
296 if (sk->sk_state != TCP_CLOSE)
297 goto out_unlock;
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_len >= sizeof(struct sockaddr_in6) &&
306 addr->l2tp_scope_id) {
307 /* Override any existing binding, if another
308 * one is supplied by user.
309 */
310 sk->sk_bound_dev_if = addr->l2tp_scope_id;
311 }
312
313 /* Binding to link-local address requires an
314 interface */
315 if (!sk->sk_bound_dev_if)
316 goto out_unlock_rcu;
317
318 err = -ENODEV;
319 dev = dev_get_by_index_rcu(sock_net(sk),
320 sk->sk_bound_dev_if);
321 if (!dev)
322 goto out_unlock_rcu;
323 }
324
325 /* ipv4 addr of the socket is invalid. Only the
326 * unspecified and mapped address have a v4 equivalent.
327 */
328 v4addr = LOOPBACK4_IPV6;
329 err = -EADDRNOTAVAIL;
330 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
331 goto out_unlock_rcu;
332 }
333 rcu_read_unlock();
334
335 inet->inet_rcv_saddr = inet->inet_saddr = v4addr;
336 sk->sk_v6_rcv_saddr = addr->l2tp_addr;
337 np->saddr = addr->l2tp_addr;
338
339 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
340
341 write_lock_bh(&l2tp_ip6_lock);
342 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
343 sk_del_node_init(sk);
344 write_unlock_bh(&l2tp_ip6_lock);
345
346 sock_reset_flag(sk, SOCK_ZAPPED);
347 release_sock(sk);
348 return 0;
349
350 out_unlock_rcu:
351 rcu_read_unlock();
352 out_unlock:
353 release_sock(sk);
354 return err;
355
356 out_in_use:
357 read_unlock_bh(&l2tp_ip6_lock);
358 return err;
359 }
360
l2tp_ip6_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)361 static 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 (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
371 return -EINVAL;
372
373 if (addr_len < sizeof(*lsa))
374 return -EINVAL;
375
376 if (usin->sin6_family != AF_INET6)
377 return -EINVAL;
378
379 addr_type = ipv6_addr_type(&usin->sin6_addr);
380 if (addr_type & IPV6_ADDR_MULTICAST)
381 return -EINVAL;
382
383 if (addr_type & IPV6_ADDR_MAPPED) {
384 daddr = &usin->sin6_addr;
385 if (ipv4_is_multicast(daddr->s6_addr32[3]))
386 return -EINVAL;
387 }
388
389 rc = ip6_datagram_connect(sk, uaddr, addr_len);
390
391 lock_sock(sk);
392
393 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
394
395 write_lock_bh(&l2tp_ip6_lock);
396 hlist_del_init(&sk->sk_bind_node);
397 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
398 write_unlock_bh(&l2tp_ip6_lock);
399
400 release_sock(sk);
401
402 return rc;
403 }
404
l2tp_ip6_disconnect(struct sock * sk,int flags)405 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
406 {
407 if (sock_flag(sk, SOCK_ZAPPED))
408 return 0;
409
410 return udp_disconnect(sk, flags);
411 }
412
l2tp_ip6_getname(struct socket * sock,struct sockaddr * uaddr,int * uaddr_len,int peer)413 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
414 int *uaddr_len, int peer)
415 {
416 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
417 struct sock *sk = sock->sk;
418 struct ipv6_pinfo *np = inet6_sk(sk);
419 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
420
421 lsa->l2tp_family = AF_INET6;
422 lsa->l2tp_flowinfo = 0;
423 lsa->l2tp_scope_id = 0;
424 lsa->l2tp_unused = 0;
425 if (peer) {
426 if (!lsk->peer_conn_id)
427 return -ENOTCONN;
428 lsa->l2tp_conn_id = lsk->peer_conn_id;
429 lsa->l2tp_addr = sk->sk_v6_daddr;
430 if (np->sndflow)
431 lsa->l2tp_flowinfo = np->flow_label;
432 } else {
433 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
434 lsa->l2tp_addr = np->saddr;
435 else
436 lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
437
438 lsa->l2tp_conn_id = lsk->conn_id;
439 }
440 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
441 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
442 *uaddr_len = sizeof(*lsa);
443 return 0;
444 }
445
l2tp_ip6_backlog_recv(struct sock * sk,struct sk_buff * skb)446 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
447 {
448 int rc;
449
450 /* Charge it to the socket, dropping if the queue is full. */
451 rc = sock_queue_rcv_skb(sk, skb);
452 if (rc < 0)
453 goto drop;
454
455 return 0;
456
457 drop:
458 IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
459 kfree_skb(skb);
460 return -1;
461 }
462
l2tp_ip6_push_pending_frames(struct sock * sk)463 static int l2tp_ip6_push_pending_frames(struct sock *sk)
464 {
465 struct sk_buff *skb;
466 __be32 *transhdr = NULL;
467 int err = 0;
468
469 skb = skb_peek(&sk->sk_write_queue);
470 if (skb == NULL)
471 goto out;
472
473 transhdr = (__be32 *)skb_transport_header(skb);
474 *transhdr = 0;
475
476 err = ip6_push_pending_frames(sk);
477
478 out:
479 return err;
480 }
481
482 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
483 * control frames.
484 */
l2tp_ip6_sendmsg(struct sock * sk,struct msghdr * msg,size_t len)485 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
486 {
487 struct ipv6_txoptions opt_space;
488 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
489 struct in6_addr *daddr, *final_p, final;
490 struct ipv6_pinfo *np = inet6_sk(sk);
491 struct ipv6_txoptions *opt_to_free = NULL;
492 struct ipv6_txoptions *opt = NULL;
493 struct ip6_flowlabel *flowlabel = NULL;
494 struct dst_entry *dst = NULL;
495 struct flowi6 fl6;
496 int addr_len = msg->msg_namelen;
497 int hlimit = -1;
498 int tclass = -1;
499 int dontfrag = -1;
500 int transhdrlen = 4; /* zero session-id */
501 int ulen = len + transhdrlen;
502 int err;
503
504 /* Rough check on arithmetic overflow,
505 better check is made in ip6_append_data().
506 */
507 if (len > INT_MAX)
508 return -EMSGSIZE;
509
510 /* Mirror BSD error message compatibility */
511 if (msg->msg_flags & MSG_OOB)
512 return -EOPNOTSUPP;
513
514 /*
515 * Get and verify the address.
516 */
517 memset(&fl6, 0, sizeof(fl6));
518
519 fl6.flowi6_mark = sk->sk_mark;
520
521 if (lsa) {
522 if (addr_len < SIN6_LEN_RFC2133)
523 return -EINVAL;
524
525 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
526 return -EAFNOSUPPORT;
527
528 daddr = &lsa->l2tp_addr;
529 if (np->sndflow) {
530 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
531 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
532 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
533 if (flowlabel == NULL)
534 return -EINVAL;
535 }
536 }
537
538 /*
539 * Otherwise it will be difficult to maintain
540 * sk->sk_dst_cache.
541 */
542 if (sk->sk_state == TCP_ESTABLISHED &&
543 ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
544 daddr = &sk->sk_v6_daddr;
545
546 if (addr_len >= sizeof(struct sockaddr_in6) &&
547 lsa->l2tp_scope_id &&
548 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
549 fl6.flowi6_oif = lsa->l2tp_scope_id;
550 } else {
551 if (sk->sk_state != TCP_ESTABLISHED)
552 return -EDESTADDRREQ;
553
554 daddr = &sk->sk_v6_daddr;
555 fl6.flowlabel = np->flow_label;
556 }
557
558 if (fl6.flowi6_oif == 0)
559 fl6.flowi6_oif = sk->sk_bound_dev_if;
560
561 if (msg->msg_controllen) {
562 opt = &opt_space;
563 memset(opt, 0, sizeof(struct ipv6_txoptions));
564 opt->tot_len = sizeof(struct ipv6_txoptions);
565
566 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
567 &hlimit, &tclass, &dontfrag);
568 if (err < 0) {
569 fl6_sock_release(flowlabel);
570 return err;
571 }
572 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
573 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
574 if (flowlabel == NULL)
575 return -EINVAL;
576 }
577 if (!(opt->opt_nflen|opt->opt_flen))
578 opt = NULL;
579 }
580
581 if (!opt) {
582 opt = txopt_get(np);
583 opt_to_free = opt;
584 }
585 if (flowlabel)
586 opt = fl6_merge_options(&opt_space, flowlabel, opt);
587 opt = ipv6_fixup_options(&opt_space, opt);
588
589 fl6.flowi6_proto = sk->sk_protocol;
590 if (!ipv6_addr_any(daddr))
591 fl6.daddr = *daddr;
592 else
593 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
594 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
595 fl6.saddr = np->saddr;
596
597 final_p = fl6_update_dst(&fl6, opt, &final);
598
599 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
600 fl6.flowi6_oif = np->mcast_oif;
601 else if (!fl6.flowi6_oif)
602 fl6.flowi6_oif = np->ucast_oif;
603
604 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
605
606 dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
607 if (IS_ERR(dst)) {
608 err = PTR_ERR(dst);
609 goto out;
610 }
611
612 if (hlimit < 0)
613 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
614
615 if (tclass < 0)
616 tclass = np->tclass;
617
618 if (dontfrag < 0)
619 dontfrag = np->dontfrag;
620
621 if (msg->msg_flags & MSG_CONFIRM)
622 goto do_confirm;
623
624 back_from_confirm:
625 lock_sock(sk);
626 err = ip6_append_data(sk, ip_generic_getfrag, msg,
627 ulen, transhdrlen, hlimit, tclass, opt,
628 &fl6, (struct rt6_info *)dst,
629 msg->msg_flags, dontfrag);
630 if (err)
631 ip6_flush_pending_frames(sk);
632 else if (!(msg->msg_flags & MSG_MORE))
633 err = l2tp_ip6_push_pending_frames(sk);
634 release_sock(sk);
635 done:
636 dst_release(dst);
637 out:
638 fl6_sock_release(flowlabel);
639 txopt_put(opt_to_free);
640
641 return err < 0 ? err : len;
642
643 do_confirm:
644 dst_confirm(dst);
645 if (!(msg->msg_flags & MSG_PROBE) || len)
646 goto back_from_confirm;
647 err = 0;
648 goto done;
649 }
650
l2tp_ip6_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int noblock,int flags,int * addr_len)651 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
652 int noblock, int flags, int *addr_len)
653 {
654 struct ipv6_pinfo *np = inet6_sk(sk);
655 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
656 size_t copied = 0;
657 int err = -EOPNOTSUPP;
658 struct sk_buff *skb;
659
660 if (flags & MSG_OOB)
661 goto out;
662
663 if (addr_len)
664 *addr_len = sizeof(*lsa);
665
666 if (flags & MSG_ERRQUEUE)
667 return ipv6_recv_error(sk, msg, len, addr_len);
668
669 skb = skb_recv_datagram(sk, flags, noblock, &err);
670 if (!skb)
671 goto out;
672
673 copied = skb->len;
674 if (len < copied) {
675 msg->msg_flags |= MSG_TRUNC;
676 copied = len;
677 }
678
679 err = skb_copy_datagram_msg(skb, 0, msg, copied);
680 if (err)
681 goto done;
682
683 sock_recv_timestamp(msg, sk, skb);
684
685 /* Copy the address. */
686 if (lsa) {
687 lsa->l2tp_family = AF_INET6;
688 lsa->l2tp_unused = 0;
689 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
690 lsa->l2tp_flowinfo = 0;
691 lsa->l2tp_scope_id = 0;
692 lsa->l2tp_conn_id = 0;
693 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
694 lsa->l2tp_scope_id = inet6_iif(skb);
695 }
696
697 if (np->rxopt.all)
698 ip6_datagram_recv_ctl(sk, msg, skb);
699
700 if (flags & MSG_TRUNC)
701 copied = skb->len;
702 done:
703 skb_free_datagram(sk, skb);
704 out:
705 return err ? err : copied;
706 }
707
708 static struct proto l2tp_ip6_prot = {
709 .name = "L2TP/IPv6",
710 .owner = THIS_MODULE,
711 .init = l2tp_ip6_open,
712 .close = l2tp_ip6_close,
713 .bind = l2tp_ip6_bind,
714 .connect = l2tp_ip6_connect,
715 .disconnect = l2tp_ip6_disconnect,
716 .ioctl = udp_ioctl,
717 .destroy = l2tp_ip6_destroy_sock,
718 .setsockopt = ipv6_setsockopt,
719 .getsockopt = ipv6_getsockopt,
720 .sendmsg = l2tp_ip6_sendmsg,
721 .recvmsg = l2tp_ip6_recvmsg,
722 .backlog_rcv = l2tp_ip6_backlog_recv,
723 .hash = inet_hash,
724 .unhash = inet_unhash,
725 .obj_size = sizeof(struct l2tp_ip6_sock),
726 #ifdef CONFIG_COMPAT
727 .compat_setsockopt = compat_ipv6_setsockopt,
728 .compat_getsockopt = compat_ipv6_getsockopt,
729 #endif
730 };
731
732 static const struct proto_ops l2tp_ip6_ops = {
733 .family = PF_INET6,
734 .owner = THIS_MODULE,
735 .release = inet6_release,
736 .bind = inet6_bind,
737 .connect = inet_dgram_connect,
738 .socketpair = sock_no_socketpair,
739 .accept = sock_no_accept,
740 .getname = l2tp_ip6_getname,
741 .poll = datagram_poll,
742 .ioctl = inet6_ioctl,
743 .listen = sock_no_listen,
744 .shutdown = inet_shutdown,
745 .setsockopt = sock_common_setsockopt,
746 .getsockopt = sock_common_getsockopt,
747 .sendmsg = inet_sendmsg,
748 .recvmsg = sock_common_recvmsg,
749 .mmap = sock_no_mmap,
750 .sendpage = sock_no_sendpage,
751 #ifdef CONFIG_COMPAT
752 .compat_setsockopt = compat_sock_common_setsockopt,
753 .compat_getsockopt = compat_sock_common_getsockopt,
754 #endif
755 };
756
757 static struct inet_protosw l2tp_ip6_protosw = {
758 .type = SOCK_DGRAM,
759 .protocol = IPPROTO_L2TP,
760 .prot = &l2tp_ip6_prot,
761 .ops = &l2tp_ip6_ops,
762 };
763
764 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
765 .handler = l2tp_ip6_recv,
766 };
767
l2tp_ip6_init(void)768 static int __init l2tp_ip6_init(void)
769 {
770 int err;
771
772 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
773
774 err = proto_register(&l2tp_ip6_prot, 1);
775 if (err != 0)
776 goto out;
777
778 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
779 if (err)
780 goto out1;
781
782 inet6_register_protosw(&l2tp_ip6_protosw);
783 return 0;
784
785 out1:
786 proto_unregister(&l2tp_ip6_prot);
787 out:
788 return err;
789 }
790
l2tp_ip6_exit(void)791 static void __exit l2tp_ip6_exit(void)
792 {
793 inet6_unregister_protosw(&l2tp_ip6_protosw);
794 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
795 proto_unregister(&l2tp_ip6_prot);
796 }
797
798 module_init(l2tp_ip6_init);
799 module_exit(l2tp_ip6_exit);
800
801 MODULE_LICENSE("GPL");
802 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
803 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
804 MODULE_VERSION("1.0");
805
806 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
807 * enums
808 */
809 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
810 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);
811