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TOMOYO Linux Cross Reference
Linux/net/l2tp/l2tp_ip6.c

Version: ~ [ linux-5.4-rc3 ] ~ [ linux-5.3.6 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.79 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.149 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.196 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.196 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.75 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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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/inet6_hashtables.h>
 29 #include <net/tcp_states.h>
 30 #include <net/protocol.h>
 31 #include <net/xfrm.h>
 32 
 33 #include <net/transp_v6.h>
 34 #include <net/addrconf.h>
 35 #include <net/ip6_route.h>
 36 
 37 #include "l2tp_core.h"
 38 
 39 struct l2tp_ip6_sock {
 40         /* inet_sock has to be the first member of l2tp_ip6_sock */
 41         struct inet_sock        inet;
 42 
 43         u32                     conn_id;
 44         u32                     peer_conn_id;
 45 
 46         /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
 47            inet6_sk_generic */
 48         struct ipv6_pinfo       inet6;
 49 };
 50 
 51 static DEFINE_RWLOCK(l2tp_ip6_lock);
 52 static struct hlist_head l2tp_ip6_table;
 53 static struct hlist_head l2tp_ip6_bind_table;
 54 
 55 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
 56 {
 57         return (struct l2tp_ip6_sock *)sk;
 58 }
 59 
 60 static struct sock *__l2tp_ip6_bind_lookup(const struct net *net,
 61                                            const struct in6_addr *laddr,
 62                                            const struct in6_addr *raddr,
 63                                            int dif, u32 tunnel_id)
 64 {
 65         struct sock *sk;
 66 
 67         sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
 68                 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
 69                 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr;
 70                 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
 71 
 72                 if (!net_eq(sock_net(sk), net))
 73                         continue;
 74 
 75                 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
 76                         continue;
 77 
 78                 if (sk_laddr && !ipv6_addr_any(sk_laddr) &&
 79                     !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr))
 80                         continue;
 81 
 82                 if (!ipv6_addr_any(sk_raddr) && raddr &&
 83                     !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr))
 84                         continue;
 85 
 86                 if (l2tp->conn_id != tunnel_id)
 87                         continue;
 88 
 89                 goto found;
 90         }
 91 
 92         sk = NULL;
 93 found:
 94         return sk;
 95 }
 96 
 97 /* When processing receive frames, there are two cases to
 98  * consider. Data frames consist of a non-zero session-id and an
 99  * optional cookie. Control frames consist of a regular L2TP header
100  * preceded by 32-bits of zeros.
101  *
102  * L2TPv3 Session Header Over IP
103  *
104  *  0                   1                   2                   3
105  *  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
106  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
107  * |                           Session ID                          |
108  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
109  * |               Cookie (optional, maximum 64 bits)...
110  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
111  *                                                                 |
112  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
113  *
114  * L2TPv3 Control Message Header Over IP
115  *
116  *  0                   1                   2                   3
117  *  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
118  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
119  * |                      (32 bits of zeros)                       |
120  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
121  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
122  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
123  * |                     Control Connection ID                     |
124  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
125  * |               Ns              |               Nr              |
126  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
127  *
128  * All control frames are passed to userspace.
129  */
130 static int l2tp_ip6_recv(struct sk_buff *skb)
131 {
132         struct net *net = dev_net(skb->dev);
133         struct sock *sk;
134         u32 session_id;
135         u32 tunnel_id;
136         unsigned char *ptr, *optr;
137         struct l2tp_session *session;
138         struct l2tp_tunnel *tunnel = NULL;
139         int length;
140 
141         if (!pskb_may_pull(skb, 4))
142                 goto discard;
143 
144         /* Point to L2TP header */
145         optr = ptr = skb->data;
146         session_id = ntohl(*((__be32 *) ptr));
147         ptr += 4;
148 
149         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
150          * the session_id. If it is 0, the packet is a L2TP control
151          * frame and the session_id value can be discarded.
152          */
153         if (session_id == 0) {
154                 __skb_pull(skb, 4);
155                 goto pass_up;
156         }
157 
158         /* Ok, this is a data packet. Lookup the session. */
159         session = l2tp_session_get(net, NULL, session_id, true);
160         if (!session)
161                 goto discard;
162 
163         tunnel = session->tunnel;
164         if (!tunnel)
165                 goto discard_sess;
166 
167         /* Trace packet contents, if enabled */
168         if (tunnel->debug & L2TP_MSG_DATA) {
169                 length = min(32u, skb->len);
170                 if (!pskb_may_pull(skb, length))
171                         goto discard_sess;
172 
173                 /* Point to L2TP header */
174                 optr = ptr = skb->data;
175                 ptr += 4;
176                 pr_debug("%s: ip recv\n", tunnel->name);
177                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
178         }
179 
180         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
181                          tunnel->recv_payload_hook);
182         l2tp_session_dec_refcount(session);
183 
184         return 0;
185 
186 pass_up:
187         /* Get the tunnel_id from the L2TP header */
188         if (!pskb_may_pull(skb, 12))
189                 goto discard;
190 
191         if ((skb->data[0] & 0xc0) != 0xc0)
192                 goto discard;
193 
194         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
195         tunnel = l2tp_tunnel_find(net, tunnel_id);
196         if (tunnel) {
197                 sk = tunnel->sock;
198                 sock_hold(sk);
199         } else {
200                 struct ipv6hdr *iph = ipv6_hdr(skb);
201 
202                 read_lock_bh(&l2tp_ip6_lock);
203                 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
204                                             inet6_iif(skb), tunnel_id);
205                 if (!sk) {
206                         read_unlock_bh(&l2tp_ip6_lock);
207                         goto discard;
208                 }
209 
210                 sock_hold(sk);
211                 read_unlock_bh(&l2tp_ip6_lock);
212         }
213 
214         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
215                 goto discard_put;
216 
217         nf_reset(skb);
218 
219         return sk_receive_skb(sk, skb, 1);
220 
221 discard_sess:
222         if (session->deref)
223                 session->deref(session);
224         l2tp_session_dec_refcount(session);
225         goto discard;
226 
227 discard_put:
228         sock_put(sk);
229 
230 discard:
231         kfree_skb(skb);
232         return 0;
233 }
234 
235 static int l2tp_ip6_open(struct sock *sk)
236 {
237         /* Prevent autobind. We don't have ports. */
238         inet_sk(sk)->inet_num = IPPROTO_L2TP;
239 
240         write_lock_bh(&l2tp_ip6_lock);
241         sk_add_node(sk, &l2tp_ip6_table);
242         write_unlock_bh(&l2tp_ip6_lock);
243 
244         return 0;
245 }
246 
247 static void l2tp_ip6_close(struct sock *sk, long timeout)
248 {
249         write_lock_bh(&l2tp_ip6_lock);
250         hlist_del_init(&sk->sk_bind_node);
251         sk_del_node_init(sk);
252         write_unlock_bh(&l2tp_ip6_lock);
253 
254         sk_common_release(sk);
255 }
256 
257 static void l2tp_ip6_destroy_sock(struct sock *sk)
258 {
259         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
260 
261         lock_sock(sk);
262         ip6_flush_pending_frames(sk);
263         release_sock(sk);
264 
265         if (tunnel) {
266                 l2tp_tunnel_closeall(tunnel);
267                 sock_put(sk);
268         }
269 
270         inet6_destroy_sock(sk);
271 }
272 
273 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
274 {
275         struct inet_sock *inet = inet_sk(sk);
276         struct ipv6_pinfo *np = inet6_sk(sk);
277         struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
278         struct net *net = sock_net(sk);
279         __be32 v4addr = 0;
280         int bound_dev_if;
281         int addr_type;
282         int err;
283 
284         if (addr->l2tp_family != AF_INET6)
285                 return -EINVAL;
286         if (addr_len < sizeof(*addr))
287                 return -EINVAL;
288 
289         addr_type = ipv6_addr_type(&addr->l2tp_addr);
290 
291         /* l2tp_ip6 sockets are IPv6 only */
292         if (addr_type == IPV6_ADDR_MAPPED)
293                 return -EADDRNOTAVAIL;
294 
295         /* L2TP is point-point, not multicast */
296         if (addr_type & IPV6_ADDR_MULTICAST)
297                 return -EADDRNOTAVAIL;
298 
299         lock_sock(sk);
300 
301         err = -EINVAL;
302         if (!sock_flag(sk, SOCK_ZAPPED))
303                 goto out_unlock;
304 
305         if (sk->sk_state != TCP_CLOSE)
306                 goto out_unlock;
307 
308         bound_dev_if = sk->sk_bound_dev_if;
309 
310         /* Check if the address belongs to the host. */
311         rcu_read_lock();
312         if (addr_type != IPV6_ADDR_ANY) {
313                 struct net_device *dev = NULL;
314 
315                 if (addr_type & IPV6_ADDR_LINKLOCAL) {
316                         if (addr->l2tp_scope_id)
317                                 bound_dev_if = addr->l2tp_scope_id;
318 
319                         /* Binding to link-local address requires an
320                          * interface.
321                          */
322                         if (!bound_dev_if)
323                                 goto out_unlock_rcu;
324 
325                         err = -ENODEV;
326                         dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
327                         if (!dev)
328                                 goto out_unlock_rcu;
329                 }
330 
331                 /* ipv4 addr of the socket is invalid.  Only the
332                  * unspecified and mapped address have a v4 equivalent.
333                  */
334                 v4addr = LOOPBACK4_IPV6;
335                 err = -EADDRNOTAVAIL;
336                 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
337                         goto out_unlock_rcu;
338         }
339         rcu_read_unlock();
340 
341         write_lock_bh(&l2tp_ip6_lock);
342         if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
343                                    addr->l2tp_conn_id)) {
344                 write_unlock_bh(&l2tp_ip6_lock);
345                 err = -EADDRINUSE;
346                 goto out_unlock;
347         }
348 
349         inet->inet_saddr = v4addr;
350         inet->inet_rcv_saddr = v4addr;
351         sk->sk_bound_dev_if = bound_dev_if;
352         sk->sk_v6_rcv_saddr = addr->l2tp_addr;
353         np->saddr = addr->l2tp_addr;
354 
355         l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
356 
357         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
358         sk_del_node_init(sk);
359         write_unlock_bh(&l2tp_ip6_lock);
360 
361         sock_reset_flag(sk, SOCK_ZAPPED);
362         release_sock(sk);
363         return 0;
364 
365 out_unlock_rcu:
366         rcu_read_unlock();
367 out_unlock:
368         release_sock(sk);
369 
370         return err;
371 }
372 
373 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
374                             int addr_len)
375 {
376         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
377         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
378         struct in6_addr *daddr;
379         int     addr_type;
380         int rc;
381 
382         if (addr_len < sizeof(*lsa))
383                 return -EINVAL;
384 
385         if (usin->sin6_family != AF_INET6)
386                 return -EINVAL;
387 
388         addr_type = ipv6_addr_type(&usin->sin6_addr);
389         if (addr_type & IPV6_ADDR_MULTICAST)
390                 return -EINVAL;
391 
392         if (addr_type & IPV6_ADDR_MAPPED) {
393                 daddr = &usin->sin6_addr;
394                 if (ipv4_is_multicast(daddr->s6_addr32[3]))
395                         return -EINVAL;
396         }
397 
398         lock_sock(sk);
399 
400          /* Must bind first - autobinding does not work */
401         if (sock_flag(sk, SOCK_ZAPPED)) {
402                 rc = -EINVAL;
403                 goto out_sk;
404         }
405 
406         rc = __ip6_datagram_connect(sk, uaddr, addr_len);
407         if (rc < 0)
408                 goto out_sk;
409 
410         l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
411 
412         write_lock_bh(&l2tp_ip6_lock);
413         hlist_del_init(&sk->sk_bind_node);
414         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
415         write_unlock_bh(&l2tp_ip6_lock);
416 
417 out_sk:
418         release_sock(sk);
419 
420         return rc;
421 }
422 
423 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
424 {
425         if (sock_flag(sk, SOCK_ZAPPED))
426                 return 0;
427 
428         return __udp_disconnect(sk, flags);
429 }
430 
431 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
432                             int *uaddr_len, int peer)
433 {
434         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
435         struct sock *sk = sock->sk;
436         struct ipv6_pinfo *np = inet6_sk(sk);
437         struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
438 
439         lsa->l2tp_family = AF_INET6;
440         lsa->l2tp_flowinfo = 0;
441         lsa->l2tp_scope_id = 0;
442         lsa->l2tp_unused = 0;
443         if (peer) {
444                 if (!lsk->peer_conn_id)
445                         return -ENOTCONN;
446                 lsa->l2tp_conn_id = lsk->peer_conn_id;
447                 lsa->l2tp_addr = sk->sk_v6_daddr;
448                 if (np->sndflow)
449                         lsa->l2tp_flowinfo = np->flow_label;
450         } else {
451                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
452                         lsa->l2tp_addr = np->saddr;
453                 else
454                         lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
455 
456                 lsa->l2tp_conn_id = lsk->conn_id;
457         }
458         if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
459                 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
460         *uaddr_len = sizeof(*lsa);
461         return 0;
462 }
463 
464 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
465 {
466         int rc;
467 
468         /* Charge it to the socket, dropping if the queue is full. */
469         rc = sock_queue_rcv_skb(sk, skb);
470         if (rc < 0)
471                 goto drop;
472 
473         return 0;
474 
475 drop:
476         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
477         kfree_skb(skb);
478         return -1;
479 }
480 
481 static int l2tp_ip6_push_pending_frames(struct sock *sk)
482 {
483         struct sk_buff *skb;
484         __be32 *transhdr = NULL;
485         int err = 0;
486 
487         skb = skb_peek(&sk->sk_write_queue);
488         if (skb == NULL)
489                 goto out;
490 
491         transhdr = (__be32 *)skb_transport_header(skb);
492         *transhdr = 0;
493 
494         err = ip6_push_pending_frames(sk);
495 
496 out:
497         return err;
498 }
499 
500 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
501  * control frames.
502  */
503 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
504 {
505         struct ipv6_txoptions opt_space;
506         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
507         struct in6_addr *daddr, *final_p, final;
508         struct ipv6_pinfo *np = inet6_sk(sk);
509         struct ipv6_txoptions *opt_to_free = NULL;
510         struct ipv6_txoptions *opt = NULL;
511         struct ip6_flowlabel *flowlabel = NULL;
512         struct dst_entry *dst = NULL;
513         struct flowi6 fl6;
514         struct sockcm_cookie sockc_unused = {0};
515         struct ipcm6_cookie ipc6;
516         int addr_len = msg->msg_namelen;
517         int transhdrlen = 4; /* zero session-id */
518         int ulen = len + transhdrlen;
519         int err;
520 
521         /* Rough check on arithmetic overflow,
522            better check is made in ip6_append_data().
523          */
524         if (len > INT_MAX)
525                 return -EMSGSIZE;
526 
527         /* Mirror BSD error message compatibility */
528         if (msg->msg_flags & MSG_OOB)
529                 return -EOPNOTSUPP;
530 
531         /*
532          *      Get and verify the address.
533          */
534         memset(&fl6, 0, sizeof(fl6));
535 
536         fl6.flowi6_mark = sk->sk_mark;
537         fl6.flowi6_uid = sk->sk_uid;
538 
539         ipc6.hlimit = -1;
540         ipc6.tclass = -1;
541         ipc6.dontfrag = -1;
542 
543         if (lsa) {
544                 if (addr_len < SIN6_LEN_RFC2133)
545                         return -EINVAL;
546 
547                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
548                         return -EAFNOSUPPORT;
549 
550                 daddr = &lsa->l2tp_addr;
551                 if (np->sndflow) {
552                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
553                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
554                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
555                                 if (flowlabel == NULL)
556                                         return -EINVAL;
557                         }
558                 }
559 
560                 /*
561                  * Otherwise it will be difficult to maintain
562                  * sk->sk_dst_cache.
563                  */
564                 if (sk->sk_state == TCP_ESTABLISHED &&
565                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
566                         daddr = &sk->sk_v6_daddr;
567 
568                 if (addr_len >= sizeof(struct sockaddr_in6) &&
569                     lsa->l2tp_scope_id &&
570                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
571                         fl6.flowi6_oif = lsa->l2tp_scope_id;
572         } else {
573                 if (sk->sk_state != TCP_ESTABLISHED)
574                         return -EDESTADDRREQ;
575 
576                 daddr = &sk->sk_v6_daddr;
577                 fl6.flowlabel = np->flow_label;
578         }
579 
580         if (fl6.flowi6_oif == 0)
581                 fl6.flowi6_oif = sk->sk_bound_dev_if;
582 
583         if (msg->msg_controllen) {
584                 opt = &opt_space;
585                 memset(opt, 0, sizeof(struct ipv6_txoptions));
586                 opt->tot_len = sizeof(struct ipv6_txoptions);
587                 ipc6.opt = opt;
588 
589                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6,
590                                             &sockc_unused);
591                 if (err < 0) {
592                         fl6_sock_release(flowlabel);
593                         return err;
594                 }
595                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
596                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
597                         if (flowlabel == NULL)
598                                 return -EINVAL;
599                 }
600                 if (!(opt->opt_nflen|opt->opt_flen))
601                         opt = NULL;
602         }
603 
604         if (!opt) {
605                 opt = txopt_get(np);
606                 opt_to_free = opt;
607         }
608         if (flowlabel)
609                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
610         opt = ipv6_fixup_options(&opt_space, opt);
611         ipc6.opt = opt;
612 
613         fl6.flowi6_proto = sk->sk_protocol;
614         if (!ipv6_addr_any(daddr))
615                 fl6.daddr = *daddr;
616         else
617                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
618         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
619                 fl6.saddr = np->saddr;
620 
621         final_p = fl6_update_dst(&fl6, opt, &final);
622 
623         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
624                 fl6.flowi6_oif = np->mcast_oif;
625         else if (!fl6.flowi6_oif)
626                 fl6.flowi6_oif = np->ucast_oif;
627 
628         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
629 
630         if (ipc6.tclass < 0)
631                 ipc6.tclass = np->tclass;
632 
633         fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
634 
635         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
636         if (IS_ERR(dst)) {
637                 err = PTR_ERR(dst);
638                 goto out;
639         }
640 
641         if (ipc6.hlimit < 0)
642                 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
643 
644         if (ipc6.dontfrag < 0)
645                 ipc6.dontfrag = np->dontfrag;
646 
647         if (msg->msg_flags & MSG_CONFIRM)
648                 goto do_confirm;
649 
650 back_from_confirm:
651         lock_sock(sk);
652         err = ip6_append_data(sk, ip_generic_getfrag, msg,
653                               ulen, transhdrlen, &ipc6,
654                               &fl6, (struct rt6_info *)dst,
655                               msg->msg_flags, &sockc_unused);
656         if (err)
657                 ip6_flush_pending_frames(sk);
658         else if (!(msg->msg_flags & MSG_MORE))
659                 err = l2tp_ip6_push_pending_frames(sk);
660         release_sock(sk);
661 done:
662         dst_release(dst);
663 out:
664         fl6_sock_release(flowlabel);
665         txopt_put(opt_to_free);
666 
667         return err < 0 ? err : len;
668 
669 do_confirm:
670         if (msg->msg_flags & MSG_PROBE)
671                 dst_confirm_neigh(dst, &fl6.daddr);
672         if (!(msg->msg_flags & MSG_PROBE) || len)
673                 goto back_from_confirm;
674         err = 0;
675         goto done;
676 }
677 
678 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
679                             int noblock, int flags, int *addr_len)
680 {
681         struct ipv6_pinfo *np = inet6_sk(sk);
682         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
683         size_t copied = 0;
684         int err = -EOPNOTSUPP;
685         struct sk_buff *skb;
686 
687         if (flags & MSG_OOB)
688                 goto out;
689 
690         if (addr_len)
691                 *addr_len = sizeof(*lsa);
692 
693         if (flags & MSG_ERRQUEUE)
694                 return ipv6_recv_error(sk, msg, len, addr_len);
695 
696         skb = skb_recv_datagram(sk, flags, noblock, &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         }
723 
724         if (np->rxopt.all)
725                 ip6_datagram_recv_ctl(sk, msg, skb);
726 
727         if (flags & MSG_TRUNC)
728                 copied = skb->len;
729 done:
730         skb_free_datagram(sk, skb);
731 out:
732         return err ? err : copied;
733 }
734 
735 static struct proto l2tp_ip6_prot = {
736         .name              = "L2TP/IPv6",
737         .owner             = THIS_MODULE,
738         .init              = l2tp_ip6_open,
739         .close             = l2tp_ip6_close,
740         .bind              = l2tp_ip6_bind,
741         .connect           = l2tp_ip6_connect,
742         .disconnect        = l2tp_ip6_disconnect,
743         .ioctl             = l2tp_ioctl,
744         .destroy           = l2tp_ip6_destroy_sock,
745         .setsockopt        = ipv6_setsockopt,
746         .getsockopt        = ipv6_getsockopt,
747         .sendmsg           = l2tp_ip6_sendmsg,
748         .recvmsg           = l2tp_ip6_recvmsg,
749         .backlog_rcv       = l2tp_ip6_backlog_recv,
750         .hash              = inet6_hash,
751         .unhash            = inet_unhash,
752         .obj_size          = sizeof(struct l2tp_ip6_sock),
753 #ifdef CONFIG_COMPAT
754         .compat_setsockopt = compat_ipv6_setsockopt,
755         .compat_getsockopt = compat_ipv6_getsockopt,
756 #endif
757 };
758 
759 static const struct proto_ops l2tp_ip6_ops = {
760         .family            = PF_INET6,
761         .owner             = THIS_MODULE,
762         .release           = inet6_release,
763         .bind              = inet6_bind,
764         .connect           = inet_dgram_connect,
765         .socketpair        = sock_no_socketpair,
766         .accept            = sock_no_accept,
767         .getname           = l2tp_ip6_getname,
768         .poll              = datagram_poll,
769         .ioctl             = inet6_ioctl,
770         .listen            = sock_no_listen,
771         .shutdown          = inet_shutdown,
772         .setsockopt        = sock_common_setsockopt,
773         .getsockopt        = sock_common_getsockopt,
774         .sendmsg           = inet_sendmsg,
775         .recvmsg           = sock_common_recvmsg,
776         .mmap              = sock_no_mmap,
777         .sendpage          = sock_no_sendpage,
778 #ifdef CONFIG_COMPAT
779         .compat_setsockopt = compat_sock_common_setsockopt,
780         .compat_getsockopt = compat_sock_common_getsockopt,
781 #endif
782 };
783 
784 static struct inet_protosw l2tp_ip6_protosw = {
785         .type           = SOCK_DGRAM,
786         .protocol       = IPPROTO_L2TP,
787         .prot           = &l2tp_ip6_prot,
788         .ops            = &l2tp_ip6_ops,
789 };
790 
791 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
792         .handler        = l2tp_ip6_recv,
793 };
794 
795 static int __init l2tp_ip6_init(void)
796 {
797         int err;
798 
799         pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
800 
801         err = proto_register(&l2tp_ip6_prot, 1);
802         if (err != 0)
803                 goto out;
804 
805         err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
806         if (err)
807                 goto out1;
808 
809         inet6_register_protosw(&l2tp_ip6_protosw);
810         return 0;
811 
812 out1:
813         proto_unregister(&l2tp_ip6_prot);
814 out:
815         return err;
816 }
817 
818 static void __exit l2tp_ip6_exit(void)
819 {
820         inet6_unregister_protosw(&l2tp_ip6_protosw);
821         inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
822         proto_unregister(&l2tp_ip6_prot);
823 }
824 
825 module_init(l2tp_ip6_init);
826 module_exit(l2tp_ip6_exit);
827 
828 MODULE_LICENSE("GPL");
829 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
830 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
831 MODULE_VERSION("1.0");
832 
833 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
834  * enums
835  */
836 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
837 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);
838 

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