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 (addr->l2tp_family != AF_INET6)
270 return -EINVAL;
271 if (addr_len < sizeof(*addr))
272 return -EINVAL;
273
274 addr_type = ipv6_addr_type(&addr->l2tp_addr);
275
276 /* l2tp_ip6 sockets are IPv6 only */
277 if (addr_type == IPV6_ADDR_MAPPED)
278 return -EADDRNOTAVAIL;
279
280 /* L2TP is point-point, not multicast */
281 if (addr_type & IPV6_ADDR_MULTICAST)
282 return -EADDRNOTAVAIL;
283
284 err = -EADDRINUSE;
285 read_lock_bh(&l2tp_ip6_lock);
286 if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr,
287 sk->sk_bound_dev_if, addr->l2tp_conn_id))
288 goto out_in_use;
289 read_unlock_bh(&l2tp_ip6_lock);
290
291 lock_sock(sk);
292
293 err = -EINVAL;
294 if (!sock_flag(sk, SOCK_ZAPPED))
295 goto out_unlock;
296
297 if (sk->sk_state != TCP_CLOSE)
298 goto out_unlock;
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_len >= sizeof(struct sockaddr_in6) &&
307 addr->l2tp_scope_id) {
308 /* Override any existing binding, if another
309 * one is supplied by user.
310 */
311 sk->sk_bound_dev_if = addr->l2tp_scope_id;
312 }
313
314 /* Binding to link-local address requires an
315 interface */
316 if (!sk->sk_bound_dev_if)
317 goto out_unlock_rcu;
318
319 err = -ENODEV;
320 dev = dev_get_by_index_rcu(sock_net(sk),
321 sk->sk_bound_dev_if);
322 if (!dev)
323 goto out_unlock_rcu;
324 }
325
326 /* ipv4 addr of the socket is invalid. Only the
327 * unspecified and mapped address have a v4 equivalent.
328 */
329 v4addr = LOOPBACK4_IPV6;
330 err = -EADDRNOTAVAIL;
331 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
332 goto out_unlock_rcu;
333 }
334 rcu_read_unlock();
335
336 inet->inet_rcv_saddr = inet->inet_saddr = v4addr;
337 sk->sk_v6_rcv_saddr = addr->l2tp_addr;
338 np->saddr = addr->l2tp_addr;
339
340 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
341
342 write_lock_bh(&l2tp_ip6_lock);
343 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
344 sk_del_node_init(sk);
345 write_unlock_bh(&l2tp_ip6_lock);
346
347 sock_reset_flag(sk, SOCK_ZAPPED);
348 release_sock(sk);
349 return 0;
350
351 out_unlock_rcu:
352 rcu_read_unlock();
353 out_unlock:
354 release_sock(sk);
355 return err;
356
357 out_in_use:
358 read_unlock_bh(&l2tp_ip6_lock);
359 return err;
360 }
361
l2tp_ip6_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)362 static 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 (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
372 return -EINVAL;
373
374 if (addr_len < sizeof(*lsa))
375 return -EINVAL;
376
377 if (usin->sin6_family != AF_INET6)
378 return -EINVAL;
379
380 addr_type = ipv6_addr_type(&usin->sin6_addr);
381 if (addr_type & IPV6_ADDR_MULTICAST)
382 return -EINVAL;
383
384 if (addr_type & IPV6_ADDR_MAPPED) {
385 daddr = &usin->sin6_addr;
386 if (ipv4_is_multicast(daddr->s6_addr32[3]))
387 return -EINVAL;
388 }
389
390 rc = ip6_datagram_connect(sk, uaddr, addr_len);
391
392 lock_sock(sk);
393
394 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
395
396 write_lock_bh(&l2tp_ip6_lock);
397 hlist_del_init(&sk->sk_bind_node);
398 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
399 write_unlock_bh(&l2tp_ip6_lock);
400
401 release_sock(sk);
402
403 return rc;
404 }
405
l2tp_ip6_disconnect(struct sock * sk,int flags)406 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
407 {
408 if (sock_flag(sk, SOCK_ZAPPED))
409 return 0;
410
411 return udp_disconnect(sk, flags);
412 }
413
l2tp_ip6_getname(struct socket * sock,struct sockaddr * uaddr,int * uaddr_len,int peer)414 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
415 int *uaddr_len, int peer)
416 {
417 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
418 struct sock *sk = sock->sk;
419 struct ipv6_pinfo *np = inet6_sk(sk);
420 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
421
422 lsa->l2tp_family = AF_INET6;
423 lsa->l2tp_flowinfo = 0;
424 lsa->l2tp_scope_id = 0;
425 lsa->l2tp_unused = 0;
426 if (peer) {
427 if (!lsk->peer_conn_id)
428 return -ENOTCONN;
429 lsa->l2tp_conn_id = lsk->peer_conn_id;
430 lsa->l2tp_addr = sk->sk_v6_daddr;
431 if (np->sndflow)
432 lsa->l2tp_flowinfo = np->flow_label;
433 } else {
434 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
435 lsa->l2tp_addr = np->saddr;
436 else
437 lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
438
439 lsa->l2tp_conn_id = lsk->conn_id;
440 }
441 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
442 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
443 *uaddr_len = sizeof(*lsa);
444 return 0;
445 }
446
l2tp_ip6_backlog_recv(struct sock * sk,struct sk_buff * skb)447 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
448 {
449 int rc;
450
451 /* Charge it to the socket, dropping if the queue is full. */
452 rc = sock_queue_rcv_skb(sk, skb);
453 if (rc < 0)
454 goto drop;
455
456 return 0;
457
458 drop:
459 IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
460 kfree_skb(skb);
461 return -1;
462 }
463
l2tp_ip6_push_pending_frames(struct sock * sk)464 static int l2tp_ip6_push_pending_frames(struct sock *sk)
465 {
466 struct sk_buff *skb;
467 __be32 *transhdr = NULL;
468 int err = 0;
469
470 skb = skb_peek(&sk->sk_write_queue);
471 if (skb == NULL)
472 goto out;
473
474 transhdr = (__be32 *)skb_transport_header(skb);
475 *transhdr = 0;
476
477 err = ip6_push_pending_frames(sk);
478
479 out:
480 return err;
481 }
482
483 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
484 * control frames.
485 */
l2tp_ip6_sendmsg(struct kiocb * iocb,struct sock * sk,struct msghdr * msg,size_t len)486 static int l2tp_ip6_sendmsg(struct kiocb *iocb, struct sock *sk,
487 struct msghdr *msg, size_t len)
488 {
489 struct ipv6_txoptions opt_space;
490 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
491 struct in6_addr *daddr, *final_p, final;
492 struct ipv6_pinfo *np = inet6_sk(sk);
493 struct ipv6_txoptions *opt_to_free = NULL;
494 struct ipv6_txoptions *opt = NULL;
495 struct ip6_flowlabel *flowlabel = NULL;
496 struct dst_entry *dst = NULL;
497 struct flowi6 fl6;
498 int addr_len = msg->msg_namelen;
499 int hlimit = -1;
500 int tclass = -1;
501 int dontfrag = -1;
502 int transhdrlen = 4; /* zero session-id */
503 int ulen = len + transhdrlen;
504 int err;
505
506 /* Rough check on arithmetic overflow,
507 better check is made in ip6_append_data().
508 */
509 if (len > INT_MAX)
510 return -EMSGSIZE;
511
512 /* Mirror BSD error message compatibility */
513 if (msg->msg_flags & MSG_OOB)
514 return -EOPNOTSUPP;
515
516 /*
517 * Get and verify the address.
518 */
519 memset(&fl6, 0, sizeof(fl6));
520
521 fl6.flowi6_mark = sk->sk_mark;
522 fl6.flowi6_uid = sk->sk_uid;
523
524 if (lsa) {
525 if (addr_len < SIN6_LEN_RFC2133)
526 return -EINVAL;
527
528 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
529 return -EAFNOSUPPORT;
530
531 daddr = &lsa->l2tp_addr;
532 if (np->sndflow) {
533 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
534 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
535 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
536 if (flowlabel == NULL)
537 return -EINVAL;
538 }
539 }
540
541 /*
542 * Otherwise it will be difficult to maintain
543 * sk->sk_dst_cache.
544 */
545 if (sk->sk_state == TCP_ESTABLISHED &&
546 ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
547 daddr = &sk->sk_v6_daddr;
548
549 if (addr_len >= sizeof(struct sockaddr_in6) &&
550 lsa->l2tp_scope_id &&
551 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
552 fl6.flowi6_oif = lsa->l2tp_scope_id;
553 } else {
554 if (sk->sk_state != TCP_ESTABLISHED)
555 return -EDESTADDRREQ;
556
557 daddr = &sk->sk_v6_daddr;
558 fl6.flowlabel = np->flow_label;
559 }
560
561 if (fl6.flowi6_oif == 0)
562 fl6.flowi6_oif = sk->sk_bound_dev_if;
563
564 if (msg->msg_controllen) {
565 opt = &opt_space;
566 memset(opt, 0, sizeof(struct ipv6_txoptions));
567 opt->tot_len = sizeof(struct ipv6_txoptions);
568
569 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
570 &hlimit, &tclass, &dontfrag);
571 if (err < 0) {
572 fl6_sock_release(flowlabel);
573 return err;
574 }
575 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
576 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
577 if (flowlabel == NULL)
578 return -EINVAL;
579 }
580 if (!(opt->opt_nflen|opt->opt_flen))
581 opt = NULL;
582 }
583
584 if (!opt) {
585 opt = txopt_get(np);
586 opt_to_free = opt;
587 }
588 if (flowlabel)
589 opt = fl6_merge_options(&opt_space, flowlabel, opt);
590 opt = ipv6_fixup_options(&opt_space, opt);
591
592 fl6.flowi6_proto = sk->sk_protocol;
593 if (!ipv6_addr_any(daddr))
594 fl6.daddr = *daddr;
595 else
596 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
597 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
598 fl6.saddr = np->saddr;
599
600 final_p = fl6_update_dst(&fl6, opt, &final);
601
602 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
603 fl6.flowi6_oif = np->mcast_oif;
604 else if (!fl6.flowi6_oif)
605 fl6.flowi6_oif = np->ucast_oif;
606
607 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
608
609 dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
610 if (IS_ERR(dst)) {
611 err = PTR_ERR(dst);
612 goto out;
613 }
614
615 if (hlimit < 0)
616 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
617
618 if (tclass < 0)
619 tclass = np->tclass;
620
621 if (dontfrag < 0)
622 dontfrag = np->dontfrag;
623
624 if (msg->msg_flags & MSG_CONFIRM)
625 goto do_confirm;
626
627 back_from_confirm:
628 lock_sock(sk);
629 err = ip6_append_data(sk, ip_generic_getfrag, msg->msg_iov,
630 ulen, transhdrlen, hlimit, tclass, opt,
631 &fl6, (struct rt6_info *)dst,
632 msg->msg_flags, dontfrag);
633 if (err)
634 ip6_flush_pending_frames(sk);
635 else if (!(msg->msg_flags & MSG_MORE))
636 err = l2tp_ip6_push_pending_frames(sk);
637 release_sock(sk);
638 done:
639 dst_release(dst);
640 out:
641 fl6_sock_release(flowlabel);
642 txopt_put(opt_to_free);
643
644 return err < 0 ? err : len;
645
646 do_confirm:
647 dst_confirm(dst);
648 if (!(msg->msg_flags & MSG_PROBE) || len)
649 goto back_from_confirm;
650 err = 0;
651 goto done;
652 }
653
l2tp_ip6_recvmsg(struct kiocb * iocb,struct sock * sk,struct msghdr * msg,size_t len,int noblock,int flags,int * addr_len)654 static int l2tp_ip6_recvmsg(struct kiocb *iocb, struct sock *sk,
655 struct msghdr *msg, size_t len, int noblock,
656 int flags, int *addr_len)
657 {
658 struct ipv6_pinfo *np = inet6_sk(sk);
659 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
660 size_t copied = 0;
661 int err = -EOPNOTSUPP;
662 struct sk_buff *skb;
663
664 if (flags & MSG_OOB)
665 goto out;
666
667 if (addr_len)
668 *addr_len = sizeof(*lsa);
669
670 if (flags & MSG_ERRQUEUE)
671 return ipv6_recv_error(sk, msg, len, addr_len);
672
673 skb = skb_recv_datagram(sk, flags, noblock, &err);
674 if (!skb)
675 goto out;
676
677 copied = skb->len;
678 if (len < copied) {
679 msg->msg_flags |= MSG_TRUNC;
680 copied = len;
681 }
682
683 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
684 if (err)
685 goto done;
686
687 sock_recv_timestamp(msg, sk, skb);
688
689 /* Copy the address. */
690 if (lsa) {
691 lsa->l2tp_family = AF_INET6;
692 lsa->l2tp_unused = 0;
693 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
694 lsa->l2tp_flowinfo = 0;
695 lsa->l2tp_scope_id = 0;
696 lsa->l2tp_conn_id = 0;
697 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
698 lsa->l2tp_scope_id = inet6_iif(skb);
699 }
700
701 if (np->rxopt.all)
702 ip6_datagram_recv_ctl(sk, msg, skb);
703
704 if (flags & MSG_TRUNC)
705 copied = skb->len;
706 done:
707 skb_free_datagram(sk, skb);
708 out:
709 return err ? err : copied;
710 }
711
712 static struct proto l2tp_ip6_prot = {
713 .name = "L2TP/IPv6",
714 .owner = THIS_MODULE,
715 .init = l2tp_ip6_open,
716 .close = l2tp_ip6_close,
717 .bind = l2tp_ip6_bind,
718 .connect = l2tp_ip6_connect,
719 .disconnect = l2tp_ip6_disconnect,
720 .ioctl = l2tp_ioctl,
721 .destroy = l2tp_ip6_destroy_sock,
722 .setsockopt = ipv6_setsockopt,
723 .getsockopt = ipv6_getsockopt,
724 .sendmsg = l2tp_ip6_sendmsg,
725 .recvmsg = l2tp_ip6_recvmsg,
726 .backlog_rcv = l2tp_ip6_backlog_recv,
727 .hash = inet_hash,
728 .unhash = inet_unhash,
729 .obj_size = sizeof(struct l2tp_ip6_sock),
730 #ifdef CONFIG_COMPAT
731 .compat_setsockopt = compat_ipv6_setsockopt,
732 .compat_getsockopt = compat_ipv6_getsockopt,
733 #endif
734 };
735
736 static const struct proto_ops l2tp_ip6_ops = {
737 .family = PF_INET6,
738 .owner = THIS_MODULE,
739 .release = inet6_release,
740 .bind = inet6_bind,
741 .connect = inet_dgram_connect,
742 .socketpair = sock_no_socketpair,
743 .accept = sock_no_accept,
744 .getname = l2tp_ip6_getname,
745 .poll = datagram_poll,
746 .ioctl = inet6_ioctl,
747 .listen = sock_no_listen,
748 .shutdown = inet_shutdown,
749 .setsockopt = sock_common_setsockopt,
750 .getsockopt = sock_common_getsockopt,
751 .sendmsg = inet_sendmsg,
752 .recvmsg = sock_common_recvmsg,
753 .mmap = sock_no_mmap,
754 .sendpage = sock_no_sendpage,
755 #ifdef CONFIG_COMPAT
756 .compat_setsockopt = compat_sock_common_setsockopt,
757 .compat_getsockopt = compat_sock_common_getsockopt,
758 #endif
759 };
760
761 static struct inet_protosw l2tp_ip6_protosw = {
762 .type = SOCK_DGRAM,
763 .protocol = IPPROTO_L2TP,
764 .prot = &l2tp_ip6_prot,
765 .ops = &l2tp_ip6_ops,
766 };
767
768 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
769 .handler = l2tp_ip6_recv,
770 };
771
l2tp_ip6_init(void)772 static int __init l2tp_ip6_init(void)
773 {
774 int err;
775
776 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
777
778 err = proto_register(&l2tp_ip6_prot, 1);
779 if (err != 0)
780 goto out;
781
782 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
783 if (err)
784 goto out1;
785
786 inet6_register_protosw(&l2tp_ip6_protosw);
787 return 0;
788
789 out1:
790 proto_unregister(&l2tp_ip6_prot);
791 out:
792 return err;
793 }
794
l2tp_ip6_exit(void)795 static void __exit l2tp_ip6_exit(void)
796 {
797 inet6_unregister_protosw(&l2tp_ip6_protosw);
798 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
799 proto_unregister(&l2tp_ip6_prot);
800 }
801
802 module_init(l2tp_ip6_init);
803 module_exit(l2tp_ip6_exit);
804
805 MODULE_LICENSE("GPL");
806 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
807 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
808 MODULE_VERSION("1.0");
809
810 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
811 * enums
812 */
813 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
814