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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#include <net/net_namespace.h>
26#include <net/netns/generic.h>
27
28#include <net/transp_v6.h>
29#include <net/addrconf.h>
30#include <net/ip6_route.h>
31
32#include "l2tp_core.h"
33
34/* per-net private data for this module */
35static unsigned int l2tp_ip6_net_id;
36struct l2tp_ip6_net {
37 rwlock_t l2tp_ip6_lock;
38 struct hlist_head l2tp_ip6_table;
39 struct hlist_head l2tp_ip6_bind_table;
40};
41
42struct l2tp_ip6_sock {
43 /* inet_sock has to be the first member of l2tp_ip6_sock */
44 struct inet_sock inet;
45
46 u32 conn_id;
47 u32 peer_conn_id;
48
49 struct ipv6_pinfo inet6;
50};
51
52static struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
53{
54 return (struct l2tp_ip6_sock *)sk;
55}
56
57static struct l2tp_ip6_net *l2tp_ip6_pernet(const struct net *net)
58{
59 return net_generic(net, l2tp_ip6_net_id);
60}
61
62static struct sock *__l2tp_ip6_bind_lookup(const struct net *net,
63 const struct in6_addr *laddr,
64 const struct in6_addr *raddr,
65 int dif, u32 tunnel_id)
66{
67 struct l2tp_ip6_net *pn = l2tp_ip6_pernet(net);
68 struct sock *sk;
69
70 sk_for_each_bound(sk, &pn->l2tp_ip6_bind_table) {
71 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
72 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr;
73 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
74 int bound_dev_if;
75
76 if (!net_eq(sock_net(sk), net))
77 continue;
78
79 bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
80 if (bound_dev_if && dif && bound_dev_if != dif)
81 continue;
82
83 if (sk_laddr && !ipv6_addr_any(sk_laddr) &&
84 !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr))
85 continue;
86
87 if (!ipv6_addr_any(sk_raddr) && raddr &&
88 !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr))
89 continue;
90
91 if (l2tp->conn_id != tunnel_id)
92 continue;
93
94 goto found;
95 }
96
97 sk = NULL;
98found:
99 return sk;
100}
101
102/* When processing receive frames, there are two cases to
103 * consider. Data frames consist of a non-zero session-id and an
104 * optional cookie. Control frames consist of a regular L2TP header
105 * preceded by 32-bits of zeros.
106 *
107 * L2TPv3 Session Header Over IP
108 *
109 * 0 1 2 3
110 * 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
111 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
112 * | Session ID |
113 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
114 * | Cookie (optional, maximum 64 bits)...
115 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
116 * |
117 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
118 *
119 * L2TPv3 Control Message Header Over IP
120 *
121 * 0 1 2 3
122 * 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
123 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
124 * | (32 bits of zeros) |
125 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
126 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
127 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
128 * | Control Connection ID |
129 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
130 * | Ns | Nr |
131 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
132 *
133 * All control frames are passed to userspace.
134 */
135static int l2tp_ip6_recv(struct sk_buff *skb)
136{
137 struct net *net = dev_net(skb->dev);
138 struct l2tp_ip6_net *pn;
139 struct sock *sk;
140 u32 session_id;
141 u32 tunnel_id;
142 unsigned char *ptr, *optr;
143 struct l2tp_session *session;
144 struct l2tp_tunnel *tunnel = NULL;
145 struct ipv6hdr *iph;
146
147 pn = l2tp_ip6_pernet(net);
148
149 if (!pskb_may_pull(skb, 4))
150 goto discard;
151
152 /* Point to L2TP header */
153 optr = skb->data;
154 ptr = skb->data;
155 session_id = ntohl(*((__be32 *)ptr));
156 ptr += 4;
157
158 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
159 * the session_id. If it is 0, the packet is a L2TP control
160 * frame and the session_id value can be discarded.
161 */
162 if (session_id == 0) {
163 __skb_pull(skb, 4);
164 goto pass_up;
165 }
166
167 /* Ok, this is a data packet. Lookup the session. */
168 session = l2tp_v3_session_get(net, NULL, session_id);
169 if (!session)
170 goto discard;
171
172 tunnel = session->tunnel;
173 if (!tunnel)
174 goto discard_sess;
175
176 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
177 goto discard_sess;
178
179 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
180 l2tp_session_put(session);
181
182 return 0;
183
184pass_up:
185 /* Get the tunnel_id from the L2TP header */
186 if (!pskb_may_pull(skb, 12))
187 goto discard;
188
189 if ((skb->data[0] & 0xc0) != 0xc0)
190 goto discard;
191
192 tunnel_id = ntohl(*(__be32 *)&skb->data[4]);
193 iph = ipv6_hdr(skb);
194
195 read_lock_bh(&pn->l2tp_ip6_lock);
196 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
197 inet6_iif(skb), tunnel_id);
198 if (!sk) {
199 read_unlock_bh(&pn->l2tp_ip6_lock);
200 goto discard;
201 }
202 sock_hold(sk);
203 read_unlock_bh(&pn->l2tp_ip6_lock);
204
205 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
206 goto discard_put;
207
208 nf_reset_ct(skb);
209
210 return sk_receive_skb(sk, skb, 1);
211
212discard_sess:
213 l2tp_session_put(session);
214 goto discard;
215
216discard_put:
217 sock_put(sk);
218
219discard:
220 kfree_skb(skb);
221 return 0;
222}
223
224static int l2tp_ip6_hash(struct sock *sk)
225{
226 struct l2tp_ip6_net *pn = l2tp_ip6_pernet(sock_net(sk));
227
228 if (sk_unhashed(sk)) {
229 write_lock_bh(&pn->l2tp_ip6_lock);
230 sk_add_node(sk, &pn->l2tp_ip6_table);
231 write_unlock_bh(&pn->l2tp_ip6_lock);
232 }
233 return 0;
234}
235
236static void l2tp_ip6_unhash(struct sock *sk)
237{
238 struct l2tp_ip6_net *pn = l2tp_ip6_pernet(sock_net(sk));
239
240 if (sk_unhashed(sk))
241 return;
242 write_lock_bh(&pn->l2tp_ip6_lock);
243 sk_del_node_init(sk);
244 write_unlock_bh(&pn->l2tp_ip6_lock);
245}
246
247static int l2tp_ip6_open(struct sock *sk)
248{
249 /* Prevent autobind. We don't have ports. */
250 inet_sk(sk)->inet_num = IPPROTO_L2TP;
251
252 l2tp_ip6_hash(sk);
253 return 0;
254}
255
256static void l2tp_ip6_close(struct sock *sk, long timeout)
257{
258 struct l2tp_ip6_net *pn = l2tp_ip6_pernet(sock_net(sk));
259
260 write_lock_bh(&pn->l2tp_ip6_lock);
261 hlist_del_init(&sk->sk_bind_node);
262 sk_del_node_init(sk);
263 write_unlock_bh(&pn->l2tp_ip6_lock);
264
265 sk_common_release(sk);
266}
267
268static void l2tp_ip6_destroy_sock(struct sock *sk)
269{
270 struct l2tp_tunnel *tunnel;
271
272 lock_sock(sk);
273 ip6_flush_pending_frames(sk);
274 release_sock(sk);
275
276 tunnel = l2tp_sk_to_tunnel(sk);
277 if (tunnel) {
278 l2tp_tunnel_delete(tunnel);
279 l2tp_tunnel_put(tunnel);
280 }
281}
282
283static int l2tp_ip6_bind(struct sock *sk, struct sockaddr_unsized *uaddr,
284 int addr_len)
285{
286 struct inet_sock *inet = inet_sk(sk);
287 struct ipv6_pinfo *np = inet6_sk(sk);
288 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *)uaddr;
289 struct net *net = sock_net(sk);
290 struct l2tp_ip6_net *pn;
291 __be32 v4addr = 0;
292 int bound_dev_if;
293 int addr_type;
294 int err;
295
296 pn = l2tp_ip6_pernet(net);
297
298 if (addr->l2tp_family != AF_INET6)
299 return -EINVAL;
300 if (addr_len < sizeof(*addr))
301 return -EINVAL;
302
303 addr_type = ipv6_addr_type(&addr->l2tp_addr);
304
305 /* l2tp_ip6 sockets are IPv6 only */
306 if (addr_type == IPV6_ADDR_MAPPED)
307 return -EADDRNOTAVAIL;
308
309 /* L2TP is point-point, not multicast */
310 if (addr_type & IPV6_ADDR_MULTICAST)
311 return -EADDRNOTAVAIL;
312
313 lock_sock(sk);
314
315 err = -EINVAL;
316 if (!sock_flag(sk, SOCK_ZAPPED))
317 goto out_unlock;
318
319 if (sk->sk_state != TCP_CLOSE)
320 goto out_unlock;
321
322 bound_dev_if = sk->sk_bound_dev_if;
323
324 /* Check if the address belongs to the host. */
325 rcu_read_lock();
326 if (addr_type != IPV6_ADDR_ANY) {
327 struct net_device *dev = NULL;
328
329 if (addr_type & IPV6_ADDR_LINKLOCAL) {
330 if (addr->l2tp_scope_id)
331 bound_dev_if = addr->l2tp_scope_id;
332
333 /* Binding to link-local address requires an
334 * interface.
335 */
336 if (!bound_dev_if)
337 goto out_unlock_rcu;
338
339 err = -ENODEV;
340 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
341 if (!dev)
342 goto out_unlock_rcu;
343 }
344
345 /* ipv4 addr of the socket is invalid. Only the
346 * unspecified and mapped address have a v4 equivalent.
347 */
348 v4addr = LOOPBACK4_IPV6;
349 err = -EADDRNOTAVAIL;
350 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
351 goto out_unlock_rcu;
352 }
353 rcu_read_unlock();
354
355 write_lock_bh(&pn->l2tp_ip6_lock);
356 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
357 addr->l2tp_conn_id)) {
358 write_unlock_bh(&pn->l2tp_ip6_lock);
359 err = -EADDRINUSE;
360 goto out_unlock;
361 }
362
363 inet->inet_saddr = v4addr;
364 inet->inet_rcv_saddr = v4addr;
365 sk->sk_bound_dev_if = bound_dev_if;
366 sk->sk_v6_rcv_saddr = addr->l2tp_addr;
367 np->saddr = addr->l2tp_addr;
368
369 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
370
371 sk_add_bind_node(sk, &pn->l2tp_ip6_bind_table);
372 sk_del_node_init(sk);
373 write_unlock_bh(&pn->l2tp_ip6_lock);
374
375 sock_reset_flag(sk, SOCK_ZAPPED);
376 release_sock(sk);
377 return 0;
378
379out_unlock_rcu:
380 rcu_read_unlock();
381out_unlock:
382 release_sock(sk);
383
384 return err;
385}
386
387static int l2tp_ip6_connect(struct sock *sk, struct sockaddr_unsized *uaddr,
388 int addr_len)
389{
390 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
391 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
392 struct in6_addr *daddr;
393 int addr_type;
394 int rc;
395 struct l2tp_ip6_net *pn;
396
397 if (addr_len < sizeof(*lsa))
398 return -EINVAL;
399
400 if (usin->sin6_family != AF_INET6)
401 return -EINVAL;
402
403 addr_type = ipv6_addr_type(&usin->sin6_addr);
404 if (addr_type & IPV6_ADDR_MULTICAST)
405 return -EINVAL;
406
407 if (addr_type & IPV6_ADDR_MAPPED) {
408 daddr = &usin->sin6_addr;
409 if (ipv4_is_multicast(daddr->s6_addr32[3]))
410 return -EINVAL;
411 }
412
413 lock_sock(sk);
414
415 /* Must bind first - autobinding does not work */
416 if (sock_flag(sk, SOCK_ZAPPED)) {
417 rc = -EINVAL;
418 goto out_sk;
419 }
420
421 rc = __ip6_datagram_connect(sk, uaddr, addr_len);
422 if (rc < 0)
423 goto out_sk;
424
425 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
426
427 pn = l2tp_ip6_pernet(sock_net(sk));
428 write_lock_bh(&pn->l2tp_ip6_lock);
429 hlist_del_init(&sk->sk_bind_node);
430 sk_add_bind_node(sk, &pn->l2tp_ip6_bind_table);
431 write_unlock_bh(&pn->l2tp_ip6_lock);
432
433out_sk:
434 release_sock(sk);
435
436 return rc;
437}
438
439static int l2tp_ip6_disconnect(struct sock *sk, int flags)
440{
441 if (sock_flag(sk, SOCK_ZAPPED))
442 return 0;
443
444 return __udp_disconnect(sk, flags);
445}
446
447static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
448 int peer)
449{
450 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
451 struct sock *sk = sock->sk;
452 struct ipv6_pinfo *np = inet6_sk(sk);
453 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
454
455 lsa->l2tp_family = AF_INET6;
456 lsa->l2tp_flowinfo = 0;
457 lsa->l2tp_scope_id = 0;
458 lsa->l2tp_unused = 0;
459 if (peer) {
460 if (!lsk->peer_conn_id)
461 return -ENOTCONN;
462 lsa->l2tp_conn_id = lsk->peer_conn_id;
463 lsa->l2tp_addr = sk->sk_v6_daddr;
464 if (inet6_test_bit(SNDFLOW, sk))
465 lsa->l2tp_flowinfo = np->flow_label;
466 } else {
467 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
468 lsa->l2tp_addr = np->saddr;
469 else
470 lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
471
472 lsa->l2tp_conn_id = lsk->conn_id;
473 }
474 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
475 lsa->l2tp_scope_id = READ_ONCE(sk->sk_bound_dev_if);
476 return sizeof(*lsa);
477}
478
479static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
480{
481 int rc;
482
483 /* Charge it to the socket, dropping if the queue is full. */
484 rc = sock_queue_rcv_skb(sk, skb);
485 if (rc < 0)
486 goto drop;
487
488 return 0;
489
490drop:
491 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
492 kfree_skb(skb);
493 return -1;
494}
495
496static int l2tp_ip6_push_pending_frames(struct sock *sk)
497{
498 struct sk_buff *skb;
499 __be32 *transhdr = NULL;
500 int err = 0;
501
502 skb = skb_peek(&sk->sk_write_queue);
503 if (!skb)
504 goto out;
505
506 transhdr = (__be32 *)skb_transport_header(skb);
507 *transhdr = 0;
508
509 err = ip6_push_pending_frames(sk);
510
511out:
512 return err;
513}
514
515/* Userspace will call sendmsg() on the tunnel socket to send L2TP
516 * control frames.
517 */
518static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
519{
520 struct ipv6_txoptions opt_space;
521 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
522 struct in6_addr *daddr, *final_p, final;
523 struct ipv6_pinfo *np = inet6_sk(sk);
524 struct ipv6_txoptions *opt_to_free = NULL;
525 struct ipv6_txoptions *opt = NULL;
526 struct ip6_flowlabel *flowlabel = NULL;
527 struct dst_entry *dst = NULL;
528 struct flowi6 fl6;
529 struct ipcm6_cookie ipc6;
530 int addr_len = msg->msg_namelen;
531 int transhdrlen = 4; /* zero session-id */
532 int ulen;
533 int err;
534
535 /* Rough check on arithmetic overflow,
536 * better check is made in ip6_append_data().
537 */
538 if (len > INT_MAX - transhdrlen)
539 return -EMSGSIZE;
540
541 /* Mirror BSD error message compatibility */
542 if (msg->msg_flags & MSG_OOB)
543 return -EOPNOTSUPP;
544
545 /* Get and verify the address */
546 memset(&fl6, 0, sizeof(fl6));
547
548 fl6.flowi6_mark = READ_ONCE(sk->sk_mark);
549 fl6.flowi6_uid = sk_uid(sk);
550
551 ipcm6_init_sk(&ipc6, sk);
552
553 if (lsa) {
554 if (addr_len < SIN6_LEN_RFC2133)
555 return -EINVAL;
556
557 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
558 return -EAFNOSUPPORT;
559
560 daddr = &lsa->l2tp_addr;
561 if (inet6_test_bit(SNDFLOW, sk)) {
562 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
563 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) {
564 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
565 if (IS_ERR(flowlabel))
566 return -EINVAL;
567 }
568 }
569
570 /* Otherwise it will be difficult to maintain
571 * sk->sk_dst_cache.
572 */
573 if (sk->sk_state == TCP_ESTABLISHED &&
574 ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
575 daddr = &sk->sk_v6_daddr;
576
577 if (addr_len >= sizeof(struct sockaddr_in6) &&
578 lsa->l2tp_scope_id &&
579 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
580 fl6.flowi6_oif = lsa->l2tp_scope_id;
581 } else {
582 if (sk->sk_state != TCP_ESTABLISHED)
583 return -EDESTADDRREQ;
584
585 daddr = &sk->sk_v6_daddr;
586 fl6.flowlabel = np->flow_label;
587 }
588
589 if (fl6.flowi6_oif == 0)
590 fl6.flowi6_oif = READ_ONCE(sk->sk_bound_dev_if);
591
592 if (msg->msg_controllen) {
593 opt = &opt_space;
594 memset(opt, 0, sizeof(struct ipv6_txoptions));
595 opt->tot_len = sizeof(struct ipv6_txoptions);
596 ipc6.opt = opt;
597
598 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6);
599 if (err < 0) {
600 fl6_sock_release(flowlabel);
601 return err;
602 }
603 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
604 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
605 if (IS_ERR(flowlabel))
606 return -EINVAL;
607 }
608 if (!(opt->opt_nflen | opt->opt_flen))
609 opt = NULL;
610 }
611
612 if (!opt) {
613 opt = txopt_get(np);
614 opt_to_free = opt;
615 }
616 if (flowlabel)
617 opt = fl6_merge_options(&opt_space, flowlabel, opt);
618 opt = ipv6_fixup_options(&opt_space, opt);
619 ipc6.opt = opt;
620
621 fl6.flowi6_proto = sk->sk_protocol;
622 if (!ipv6_addr_any(daddr))
623 fl6.daddr = *daddr;
624 else
625 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
626 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
627 fl6.saddr = np->saddr;
628
629 final_p = fl6_update_dst(&fl6, opt, &final);
630
631 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
632 fl6.flowi6_oif = READ_ONCE(np->mcast_oif);
633 else if (!fl6.flowi6_oif)
634 fl6.flowi6_oif = READ_ONCE(np->ucast_oif);
635
636 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6));
637
638 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
639
640 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
641 if (IS_ERR(dst)) {
642 err = PTR_ERR(dst);
643 goto out;
644 }
645
646 if (ipc6.hlimit < 0)
647 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
648
649 if (msg->msg_flags & MSG_CONFIRM)
650 goto do_confirm;
651
652back_from_confirm:
653 lock_sock(sk);
654 ulen = len + (skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0);
655 err = ip6_append_data(sk, ip_generic_getfrag, msg,
656 ulen, transhdrlen, &ipc6,
657 &fl6, dst_rt6_info(dst),
658 msg->msg_flags);
659 if (err)
660 ip6_flush_pending_frames(sk);
661 else if (!(msg->msg_flags & MSG_MORE))
662 err = l2tp_ip6_push_pending_frames(sk);
663 release_sock(sk);
664done:
665 dst_release(dst);
666out:
667 fl6_sock_release(flowlabel);
668 txopt_put(opt_to_free);
669
670 return err < 0 ? err : len;
671
672do_confirm:
673 if (msg->msg_flags & MSG_PROBE)
674 dst_confirm_neigh(dst, &fl6.daddr);
675 if (!(msg->msg_flags & MSG_PROBE) || len)
676 goto back_from_confirm;
677 err = 0;
678 goto done;
679}
680
681static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
682 int flags)
683{
684 struct ipv6_pinfo *np = inet6_sk(sk);
685 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
686 size_t copied = 0;
687 int err = -EOPNOTSUPP;
688 struct sk_buff *skb;
689
690 if (flags & MSG_OOB)
691 goto out;
692
693 if (flags & MSG_ERRQUEUE)
694 return ipv6_recv_error(sk, msg, len);
695
696 skb = skb_recv_datagram(sk, flags, &err);
697 if (!skb)
698 goto out;
699
700 copied = skb->len;
701 if (len < copied) {
702 msg->msg_flags |= MSG_TRUNC;
703 copied = len;
704 }
705
706 err = skb_copy_datagram_msg(skb, 0, msg, copied);
707 if (err)
708 goto done;
709
710 sock_recv_timestamp(msg, sk, skb);
711
712 /* Copy the address. */
713 if (lsa) {
714 lsa->l2tp_family = AF_INET6;
715 lsa->l2tp_unused = 0;
716 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
717 lsa->l2tp_flowinfo = 0;
718 lsa->l2tp_scope_id = 0;
719 lsa->l2tp_conn_id = 0;
720 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
721 lsa->l2tp_scope_id = inet6_iif(skb);
722 msg->msg_namelen = sizeof(*lsa);
723 }
724
725 if (np->rxopt.all)
726 ip6_datagram_recv_ctl(sk, msg, skb);
727
728 if (flags & MSG_TRUNC)
729 copied = skb->len;
730done:
731 skb_free_datagram(sk, skb);
732out:
733 return err ? err : copied;
734}
735
736static struct proto l2tp_ip6_prot = {
737 .name = "L2TP/IPv6",
738 .owner = THIS_MODULE,
739 .init = l2tp_ip6_open,
740 .close = l2tp_ip6_close,
741 .bind = l2tp_ip6_bind,
742 .connect = l2tp_ip6_connect,
743 .disconnect = l2tp_ip6_disconnect,
744 .ioctl = l2tp_ioctl,
745 .destroy = l2tp_ip6_destroy_sock,
746 .setsockopt = ipv6_setsockopt,
747 .getsockopt = ipv6_getsockopt,
748 .sendmsg = l2tp_ip6_sendmsg,
749 .recvmsg = l2tp_ip6_recvmsg,
750 .backlog_rcv = l2tp_ip6_backlog_recv,
751 .hash = l2tp_ip6_hash,
752 .unhash = l2tp_ip6_unhash,
753 .obj_size = sizeof(struct l2tp_ip6_sock),
754 .ipv6_pinfo_offset = offsetof(struct l2tp_ip6_sock, inet6),
755};
756
757static const struct proto_ops l2tp_ip6_ops = {
758 .family = PF_INET6,
759 .owner = THIS_MODULE,
760 .release = inet6_release,
761 .bind = inet6_bind,
762 .connect = inet_dgram_connect,
763 .socketpair = sock_no_socketpair,
764 .accept = sock_no_accept,
765 .getname = l2tp_ip6_getname,
766 .poll = datagram_poll,
767 .ioctl = inet6_ioctl,
768 .gettstamp = sock_gettstamp,
769 .listen = sock_no_listen,
770 .shutdown = inet_shutdown,
771 .setsockopt = sock_common_setsockopt,
772 .getsockopt = sock_common_getsockopt,
773 .sendmsg = inet_sendmsg,
774 .recvmsg = sock_common_recvmsg,
775 .mmap = sock_no_mmap,
776#ifdef CONFIG_COMPAT
777 .compat_ioctl = inet6_compat_ioctl,
778#endif
779};
780
781static struct inet_protosw l2tp_ip6_protosw = {
782 .type = SOCK_DGRAM,
783 .protocol = IPPROTO_L2TP,
784 .prot = &l2tp_ip6_prot,
785 .ops = &l2tp_ip6_ops,
786};
787
788static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
789 .handler = l2tp_ip6_recv,
790};
791
792static __net_init int l2tp_ip6_init_net(struct net *net)
793{
794 struct l2tp_ip6_net *pn = net_generic(net, l2tp_ip6_net_id);
795
796 rwlock_init(&pn->l2tp_ip6_lock);
797 INIT_HLIST_HEAD(&pn->l2tp_ip6_table);
798 INIT_HLIST_HEAD(&pn->l2tp_ip6_bind_table);
799 return 0;
800}
801
802static __net_exit void l2tp_ip6_exit_net(struct net *net)
803{
804 struct l2tp_ip6_net *pn = l2tp_ip6_pernet(net);
805
806 write_lock_bh(&pn->l2tp_ip6_lock);
807 WARN_ON_ONCE(hlist_count_nodes(&pn->l2tp_ip6_table) != 0);
808 WARN_ON_ONCE(hlist_count_nodes(&pn->l2tp_ip6_bind_table) != 0);
809 write_unlock_bh(&pn->l2tp_ip6_lock);
810}
811
812static struct pernet_operations l2tp_ip6_net_ops = {
813 .init = l2tp_ip6_init_net,
814 .exit = l2tp_ip6_exit_net,
815 .id = &l2tp_ip6_net_id,
816 .size = sizeof(struct l2tp_ip6_net),
817};
818
819static int __init l2tp_ip6_init(void)
820{
821 int err;
822
823 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
824
825 err = register_pernet_device(&l2tp_ip6_net_ops);
826 if (err)
827 goto out;
828
829 err = proto_register(&l2tp_ip6_prot, 1);
830 if (err != 0)
831 goto out1;
832
833 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
834 if (err)
835 goto out2;
836
837 inet6_register_protosw(&l2tp_ip6_protosw);
838 return 0;
839
840out2:
841 proto_unregister(&l2tp_ip6_prot);
842out1:
843 unregister_pernet_device(&l2tp_ip6_net_ops);
844out:
845 return err;
846}
847
848static void __exit l2tp_ip6_exit(void)
849{
850 inet6_unregister_protosw(&l2tp_ip6_protosw);
851 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
852 proto_unregister(&l2tp_ip6_prot);
853 unregister_pernet_device(&l2tp_ip6_net_ops);
854}
855
856module_init(l2tp_ip6_init);
857module_exit(l2tp_ip6_exit);
858
859MODULE_LICENSE("GPL");
860MODULE_AUTHOR("Chris Elston <[email protected]>");
861MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
862MODULE_VERSION("1.0");
863
864/* Use the values of SOCK_DGRAM (2) as type and IPPROTO_L2TP (115) as protocol,
865 * because __stringify doesn't like enums
866 */
867MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 115, 2);
868MODULE_ALIAS_NET_PF_PROTO(PF_INET6, 115);