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
32 struct 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
45 static DEFINE_RWLOCK(l2tp_ip6_lock);
46 static struct hlist_head l2tp_ip6_table;
47 static struct hlist_head l2tp_ip6_bind_table;
48
l2tp_ip6_sk(const struct sock * sk)49 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
50 {
51 return (struct l2tp_ip6_sock *)sk;
52 }
53
__l2tp_ip6_bind_lookup(const struct net * net,const struct in6_addr * laddr,const struct in6_addr * raddr,int dif,u32 tunnel_id)54 static 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;
87 found:
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 */
l2tp_ip6_recv(struct sk_buff * skb)124 static 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
170 pass_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
198 discard_sess:
199 l2tp_session_dec_refcount(session);
200 goto discard;
201
202 discard_put:
203 sock_put(sk);
204
205 discard:
206 kfree_skb(skb);
207 return 0;
208 }
209
l2tp_ip6_hash(struct sock * sk)210 static 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
l2tp_ip6_unhash(struct sock * sk)220 static 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
l2tp_ip6_open(struct sock * sk)229 static 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
l2tp_ip6_close(struct sock * sk,long timeout)238 static 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
l2tp_ip6_destroy_sock(struct sock * sk)248 static 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
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 struct net *net = sock_net(sk);
266 __be32 v4addr = 0;
267 int bound_dev_if;
268 int addr_type;
269 int err;
270
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 lock_sock(sk);
287
288 err = -EINVAL;
289 if (!sock_flag(sk, SOCK_ZAPPED))
290 goto out_unlock;
291
292 if (sk->sk_state != TCP_CLOSE)
293 goto out_unlock;
294
295 bound_dev_if = sk->sk_bound_dev_if;
296
297 /* Check if the address belongs to the host. */
298 rcu_read_lock();
299 if (addr_type != IPV6_ADDR_ANY) {
300 struct net_device *dev = NULL;
301
302 if (addr_type & IPV6_ADDR_LINKLOCAL) {
303 if (addr->l2tp_scope_id)
304 bound_dev_if = addr->l2tp_scope_id;
305
306 /* Binding to link-local address requires an
307 * interface.
308 */
309 if (!bound_dev_if)
310 goto out_unlock_rcu;
311
312 err = -ENODEV;
313 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
314 if (!dev)
315 goto out_unlock_rcu;
316 }
317
318 /* ipv4 addr of the socket is invalid. Only the
319 * unspecified and mapped address have a v4 equivalent.
320 */
321 v4addr = LOOPBACK4_IPV6;
322 err = -EADDRNOTAVAIL;
323 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
324 goto out_unlock_rcu;
325 }
326 rcu_read_unlock();
327
328 write_lock_bh(&l2tp_ip6_lock);
329 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
330 addr->l2tp_conn_id)) {
331 write_unlock_bh(&l2tp_ip6_lock);
332 err = -EADDRINUSE;
333 goto out_unlock;
334 }
335
336 inet->inet_saddr = v4addr;
337 inet->inet_rcv_saddr = v4addr;
338 sk->sk_bound_dev_if = bound_dev_if;
339 sk->sk_v6_rcv_saddr = addr->l2tp_addr;
340 np->saddr = addr->l2tp_addr;
341
342 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
343
344 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
345 sk_del_node_init(sk);
346 write_unlock_bh(&l2tp_ip6_lock);
347
348 sock_reset_flag(sk, SOCK_ZAPPED);
349 release_sock(sk);
350 return 0;
351
352 out_unlock_rcu:
353 rcu_read_unlock();
354 out_unlock:
355 release_sock(sk);
356
357 return err;
358 }
359
l2tp_ip6_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)360 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
361 int addr_len)
362 {
363 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
364 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
365 struct in6_addr *daddr;
366 int addr_type;
367 int rc;
368
369 if (addr_len < sizeof(*lsa))
370 return -EINVAL;
371
372 if (usin->sin6_family != AF_INET6)
373 return -EINVAL;
374
375 addr_type = ipv6_addr_type(&usin->sin6_addr);
376 if (addr_type & IPV6_ADDR_MULTICAST)
377 return -EINVAL;
378
379 if (addr_type & IPV6_ADDR_MAPPED) {
380 daddr = &usin->sin6_addr;
381 if (ipv4_is_multicast(daddr->s6_addr32[3]))
382 return -EINVAL;
383 }
384
385 lock_sock(sk);
386
387 /* Must bind first - autobinding does not work */
388 if (sock_flag(sk, SOCK_ZAPPED)) {
389 rc = -EINVAL;
390 goto out_sk;
391 }
392
393 rc = __ip6_datagram_connect(sk, uaddr, addr_len);
394 if (rc < 0)
395 goto out_sk;
396
397 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
398
399 write_lock_bh(&l2tp_ip6_lock);
400 hlist_del_init(&sk->sk_bind_node);
401 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
402 write_unlock_bh(&l2tp_ip6_lock);
403
404 out_sk:
405 release_sock(sk);
406
407 return rc;
408 }
409
l2tp_ip6_disconnect(struct sock * sk,int flags)410 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
411 {
412 if (sock_flag(sk, SOCK_ZAPPED))
413 return 0;
414
415 return __udp_disconnect(sk, flags);
416 }
417
l2tp_ip6_getname(struct socket * sock,struct sockaddr * uaddr,int peer)418 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
419 int peer)
420 {
421 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
422 struct sock *sk = sock->sk;
423 struct ipv6_pinfo *np = inet6_sk(sk);
424 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
425
426 lsa->l2tp_family = AF_INET6;
427 lsa->l2tp_flowinfo = 0;
428 lsa->l2tp_scope_id = 0;
429 lsa->l2tp_unused = 0;
430 if (peer) {
431 if (!lsk->peer_conn_id)
432 return -ENOTCONN;
433 lsa->l2tp_conn_id = lsk->peer_conn_id;
434 lsa->l2tp_addr = sk->sk_v6_daddr;
435 if (np->sndflow)
436 lsa->l2tp_flowinfo = np->flow_label;
437 } else {
438 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
439 lsa->l2tp_addr = np->saddr;
440 else
441 lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
442
443 lsa->l2tp_conn_id = lsk->conn_id;
444 }
445 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
446 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
447 return sizeof(*lsa);
448 }
449
l2tp_ip6_backlog_recv(struct sock * sk,struct sk_buff * skb)450 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
451 {
452 int rc;
453
454 /* Charge it to the socket, dropping if the queue is full. */
455 rc = sock_queue_rcv_skb(sk, skb);
456 if (rc < 0)
457 goto drop;
458
459 return 0;
460
461 drop:
462 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
463 kfree_skb(skb);
464 return -1;
465 }
466
l2tp_ip6_push_pending_frames(struct sock * sk)467 static int l2tp_ip6_push_pending_frames(struct sock *sk)
468 {
469 struct sk_buff *skb;
470 __be32 *transhdr = NULL;
471 int err = 0;
472
473 skb = skb_peek(&sk->sk_write_queue);
474 if (!skb)
475 goto out;
476
477 transhdr = (__be32 *)skb_transport_header(skb);
478 *transhdr = 0;
479
480 err = ip6_push_pending_frames(sk);
481
482 out:
483 return err;
484 }
485
486 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
487 * control frames.
488 */
l2tp_ip6_sendmsg(struct sock * sk,struct msghdr * msg,size_t len)489 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
490 {
491 struct ipv6_txoptions opt_space;
492 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
493 struct in6_addr *daddr, *final_p, final;
494 struct ipv6_pinfo *np = inet6_sk(sk);
495 struct ipv6_txoptions *opt_to_free = NULL;
496 struct ipv6_txoptions *opt = NULL;
497 struct ip6_flowlabel *flowlabel = NULL;
498 struct dst_entry *dst = NULL;
499 struct flowi6 fl6;
500 struct ipcm6_cookie ipc6;
501 int addr_len = msg->msg_namelen;
502 int transhdrlen = 4; /* zero session-id */
503 int ulen;
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 - transhdrlen)
510 return -EMSGSIZE;
511 ulen = len + transhdrlen;
512
513 /* Mirror BSD error message compatibility */
514 if (msg->msg_flags & MSG_OOB)
515 return -EOPNOTSUPP;
516
517 /* Get and verify the address */
518 memset(&fl6, 0, sizeof(fl6));
519
520 fl6.flowi6_mark = sk->sk_mark;
521 fl6.flowi6_uid = sk->sk_uid;
522
523 ipcm6_init(&ipc6);
524
525 if (lsa) {
526 if (addr_len < SIN6_LEN_RFC2133)
527 return -EINVAL;
528
529 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
530 return -EAFNOSUPPORT;
531
532 daddr = &lsa->l2tp_addr;
533 if (np->sndflow) {
534 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
535 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
536 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
537 if (IS_ERR(flowlabel))
538 return -EINVAL;
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 ipc6.opt = opt;
569
570 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6);
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 (IS_ERR(flowlabel))
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 ipc6.opt = opt;
592
593 fl6.flowi6_proto = sk->sk_protocol;
594 if (!ipv6_addr_any(daddr))
595 fl6.daddr = *daddr;
596 else
597 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
598 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
599 fl6.saddr = np->saddr;
600
601 final_p = fl6_update_dst(&fl6, opt, &final);
602
603 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
604 fl6.flowi6_oif = np->mcast_oif;
605 else if (!fl6.flowi6_oif)
606 fl6.flowi6_oif = np->ucast_oif;
607
608 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6));
609
610 if (ipc6.tclass < 0)
611 ipc6.tclass = np->tclass;
612
613 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
614
615 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
616 if (IS_ERR(dst)) {
617 err = PTR_ERR(dst);
618 goto out;
619 }
620
621 if (ipc6.hlimit < 0)
622 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
623
624 if (ipc6.dontfrag < 0)
625 ipc6.dontfrag = np->dontfrag;
626
627 if (msg->msg_flags & MSG_CONFIRM)
628 goto do_confirm;
629
630 back_from_confirm:
631 lock_sock(sk);
632 err = ip6_append_data(sk, ip_generic_getfrag, msg,
633 ulen, transhdrlen, &ipc6,
634 &fl6, (struct rt6_info *)dst,
635 msg->msg_flags);
636 if (err)
637 ip6_flush_pending_frames(sk);
638 else if (!(msg->msg_flags & MSG_MORE))
639 err = l2tp_ip6_push_pending_frames(sk);
640 release_sock(sk);
641 done:
642 dst_release(dst);
643 out:
644 fl6_sock_release(flowlabel);
645 txopt_put(opt_to_free);
646
647 return err < 0 ? err : len;
648
649 do_confirm:
650 if (msg->msg_flags & MSG_PROBE)
651 dst_confirm_neigh(dst, &fl6.daddr);
652 if (!(msg->msg_flags & MSG_PROBE) || len)
653 goto back_from_confirm;
654 err = 0;
655 goto done;
656 }
657
l2tp_ip6_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int noblock,int flags,int * addr_len)658 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
659 int noblock, int flags, int *addr_len)
660 {
661 struct ipv6_pinfo *np = inet6_sk(sk);
662 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
663 size_t copied = 0;
664 int err = -EOPNOTSUPP;
665 struct sk_buff *skb;
666
667 if (flags & MSG_OOB)
668 goto out;
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_msg(skb, 0, msg, 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 *addr_len = sizeof(*lsa);
700 }
701
702 if (np->rxopt.all)
703 ip6_datagram_recv_ctl(sk, msg, skb);
704
705 if (flags & MSG_TRUNC)
706 copied = skb->len;
707 done:
708 skb_free_datagram(sk, skb);
709 out:
710 return err ? err : copied;
711 }
712
713 static struct proto l2tp_ip6_prot = {
714 .name = "L2TP/IPv6",
715 .owner = THIS_MODULE,
716 .init = l2tp_ip6_open,
717 .close = l2tp_ip6_close,
718 .bind = l2tp_ip6_bind,
719 .connect = l2tp_ip6_connect,
720 .disconnect = l2tp_ip6_disconnect,
721 .ioctl = l2tp_ioctl,
722 .destroy = l2tp_ip6_destroy_sock,
723 .setsockopt = ipv6_setsockopt,
724 .getsockopt = ipv6_getsockopt,
725 .sendmsg = l2tp_ip6_sendmsg,
726 .recvmsg = l2tp_ip6_recvmsg,
727 .backlog_rcv = l2tp_ip6_backlog_recv,
728 .hash = l2tp_ip6_hash,
729 .unhash = l2tp_ip6_unhash,
730 .obj_size = sizeof(struct l2tp_ip6_sock),
731 };
732
733 static const struct proto_ops l2tp_ip6_ops = {
734 .family = PF_INET6,
735 .owner = THIS_MODULE,
736 .release = inet6_release,
737 .bind = inet6_bind,
738 .connect = inet_dgram_connect,
739 .socketpair = sock_no_socketpair,
740 .accept = sock_no_accept,
741 .getname = l2tp_ip6_getname,
742 .poll = datagram_poll,
743 .ioctl = inet6_ioctl,
744 .gettstamp = sock_gettstamp,
745 .listen = sock_no_listen,
746 .shutdown = inet_shutdown,
747 .setsockopt = sock_common_setsockopt,
748 .getsockopt = sock_common_getsockopt,
749 .sendmsg = inet_sendmsg,
750 .recvmsg = sock_common_recvmsg,
751 .mmap = sock_no_mmap,
752 .sendpage = sock_no_sendpage,
753 #ifdef CONFIG_COMPAT
754 .compat_ioctl = inet6_compat_ioctl,
755 #endif
756 };
757
758 static struct inet_protosw l2tp_ip6_protosw = {
759 .type = SOCK_DGRAM,
760 .protocol = IPPROTO_L2TP,
761 .prot = &l2tp_ip6_prot,
762 .ops = &l2tp_ip6_ops,
763 };
764
765 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
766 .handler = l2tp_ip6_recv,
767 };
768
l2tp_ip6_init(void)769 static int __init l2tp_ip6_init(void)
770 {
771 int err;
772
773 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
774
775 err = proto_register(&l2tp_ip6_prot, 1);
776 if (err != 0)
777 goto out;
778
779 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
780 if (err)
781 goto out1;
782
783 inet6_register_protosw(&l2tp_ip6_protosw);
784 return 0;
785
786 out1:
787 proto_unregister(&l2tp_ip6_prot);
788 out:
789 return err;
790 }
791
l2tp_ip6_exit(void)792 static void __exit l2tp_ip6_exit(void)
793 {
794 inet6_unregister_protosw(&l2tp_ip6_protosw);
795 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
796 proto_unregister(&l2tp_ip6_prot);
797 }
798
799 module_init(l2tp_ip6_init);
800 module_exit(l2tp_ip6_exit);
801
802 MODULE_LICENSE("GPL");
803 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
804 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
805 MODULE_VERSION("1.0");
806
807 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
808 * enums
809 */
810 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
811 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);
812