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

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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(struct net *net,
 61                                            struct in6_addr *laddr,
 62                                            int dif, u32 tunnel_id)
 63 {
 64         struct sock *sk;
 65 
 66         sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
 67                 const struct in6_addr *addr = inet6_rcv_saddr(sk);
 68                 struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
 69 
 70                 if (l2tp == NULL)
 71                         continue;
 72 
 73                 if ((l2tp->conn_id == tunnel_id) &&
 74                     net_eq(sock_net(sk), net) &&
 75                     !(addr && ipv6_addr_equal(addr, laddr)) &&
 76                     !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
 77                         goto found;
 78         }
 79 
 80         sk = NULL;
 81 found:
 82         return sk;
 83 }
 84 
 85 static inline struct sock *l2tp_ip6_bind_lookup(struct net *net,
 86                                                 struct in6_addr *laddr,
 87                                                 int dif, u32 tunnel_id)
 88 {
 89         struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id);
 90         if (sk)
 91                 sock_hold(sk);
 92 
 93         return sk;
 94 }
 95 
 96 /* When processing receive frames, there are two cases to
 97  * consider. Data frames consist of a non-zero session-id and an
 98  * optional cookie. Control frames consist of a regular L2TP header
 99  * preceded by 32-bits of zeros.
100  *
101  * L2TPv3 Session Header Over IP
102  *
103  *  0                   1                   2                   3
104  *  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
105  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
106  * |                           Session ID                          |
107  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
108  * |               Cookie (optional, maximum 64 bits)...
109  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
110  *                                                                 |
111  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
112  *
113  * L2TPv3 Control Message Header Over IP
114  *
115  *  0                   1                   2                   3
116  *  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
117  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
118  * |                      (32 bits of zeros)                       |
119  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
120  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
121  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
122  * |                     Control Connection ID                     |
123  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
124  * |               Ns              |               Nr              |
125  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
126  *
127  * All control frames are passed to userspace.
128  */
129 static int l2tp_ip6_recv(struct sk_buff *skb)
130 {
131         struct sock *sk;
132         u32 session_id;
133         u32 tunnel_id;
134         unsigned char *ptr, *optr;
135         struct l2tp_session *session;
136         struct l2tp_tunnel *tunnel = NULL;
137         int length;
138 
139         if (!pskb_may_pull(skb, 4))
140                 goto discard;
141 
142         /* Point to L2TP header */
143         optr = ptr = skb->data;
144         session_id = ntohl(*((__be32 *) ptr));
145         ptr += 4;
146 
147         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
148          * the session_id. If it is 0, the packet is a L2TP control
149          * frame and the session_id value can be discarded.
150          */
151         if (session_id == 0) {
152                 __skb_pull(skb, 4);
153                 goto pass_up;
154         }
155 
156         /* Ok, this is a data packet. Lookup the session. */
157         session = l2tp_session_find(&init_net, NULL, session_id);
158         if (session == NULL)
159                 goto discard;
160 
161         tunnel = session->tunnel;
162         if (tunnel == NULL)
163                 goto discard;
164 
165         /* Trace packet contents, if enabled */
166         if (tunnel->debug & L2TP_MSG_DATA) {
167                 length = min(32u, skb->len);
168                 if (!pskb_may_pull(skb, length))
169                         goto discard;
170 
171                 /* Point to L2TP header */
172                 optr = ptr = skb->data;
173                 ptr += 4;
174                 pr_debug("%s: ip recv\n", tunnel->name);
175                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
176         }
177 
178         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
179                          tunnel->recv_payload_hook);
180         return 0;
181 
182 pass_up:
183         /* Get the tunnel_id from the L2TP header */
184         if (!pskb_may_pull(skb, 12))
185                 goto discard;
186 
187         if ((skb->data[0] & 0xc0) != 0xc0)
188                 goto discard;
189 
190         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
191         tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
192         if (tunnel != NULL)
193                 sk = tunnel->sock;
194         else {
195                 struct ipv6hdr *iph = ipv6_hdr(skb);
196 
197                 read_lock_bh(&l2tp_ip6_lock);
198                 sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr,
199                                             0, tunnel_id);
200                 read_unlock_bh(&l2tp_ip6_lock);
201         }
202 
203         if (sk == NULL)
204                 goto discard;
205 
206         sock_hold(sk);
207 
208         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
209                 goto discard_put;
210 
211         nf_reset(skb);
212 
213         return sk_receive_skb(sk, skb, 1);
214 
215 discard_put:
216         sock_put(sk);
217 
218 discard:
219         kfree_skb(skb);
220         return 0;
221 }
222 
223 static int l2tp_ip6_open(struct sock *sk)
224 {
225         /* Prevent autobind. We don't have ports. */
226         inet_sk(sk)->inet_num = IPPROTO_L2TP;
227 
228         write_lock_bh(&l2tp_ip6_lock);
229         sk_add_node(sk, &l2tp_ip6_table);
230         write_unlock_bh(&l2tp_ip6_lock);
231 
232         return 0;
233 }
234 
235 static void l2tp_ip6_close(struct sock *sk, long timeout)
236 {
237         write_lock_bh(&l2tp_ip6_lock);
238         hlist_del_init(&sk->sk_bind_node);
239         sk_del_node_init(sk);
240         write_unlock_bh(&l2tp_ip6_lock);
241 
242         sk_common_release(sk);
243 }
244 
245 static void l2tp_ip6_destroy_sock(struct sock *sk)
246 {
247         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
248 
249         lock_sock(sk);
250         ip6_flush_pending_frames(sk);
251         release_sock(sk);
252 
253         if (tunnel) {
254                 l2tp_tunnel_closeall(tunnel);
255                 sock_put(sk);
256         }
257 
258         inet6_destroy_sock(sk);
259 }
260 
261 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
262 {
263         struct inet_sock *inet = inet_sk(sk);
264         struct ipv6_pinfo *np = inet6_sk(sk);
265         struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
266         __be32 v4addr = 0;
267         int addr_type;
268         int err;
269 
270         if (!sock_flag(sk, SOCK_ZAPPED))
271                 return -EINVAL;
272         if (addr->l2tp_family != AF_INET6)
273                 return -EINVAL;
274         if (addr_len < sizeof(*addr))
275                 return -EINVAL;
276 
277         addr_type = ipv6_addr_type(&addr->l2tp_addr);
278 
279         /* l2tp_ip6 sockets are IPv6 only */
280         if (addr_type == IPV6_ADDR_MAPPED)
281                 return -EADDRNOTAVAIL;
282 
283         /* L2TP is point-point, not multicast */
284         if (addr_type & IPV6_ADDR_MULTICAST)
285                 return -EADDRNOTAVAIL;
286 
287         err = -EADDRINUSE;
288         read_lock_bh(&l2tp_ip6_lock);
289         if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr,
290                                    sk->sk_bound_dev_if, addr->l2tp_conn_id))
291                 goto out_in_use;
292         read_unlock_bh(&l2tp_ip6_lock);
293 
294         lock_sock(sk);
295 
296         err = -EINVAL;
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 
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 
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 
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 
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 
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  */
486 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
487 {
488         struct ipv6_txoptions opt_space;
489         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
490         struct in6_addr *daddr, *final_p, final;
491         struct ipv6_pinfo *np = inet6_sk(sk);
492         struct ipv6_txoptions *opt_to_free = NULL;
493         struct ipv6_txoptions *opt = NULL;
494         struct ip6_flowlabel *flowlabel = NULL;
495         struct dst_entry *dst = NULL;
496         struct flowi6 fl6;
497         int addr_len = msg->msg_namelen;
498         int hlimit = -1;
499         int tclass = -1;
500         int dontfrag = -1;
501         int transhdrlen = 4; /* zero session-id */
502         int ulen = len + transhdrlen;
503         int err;
504 
505         /* Rough check on arithmetic overflow,
506            better check is made in ip6_append_data().
507          */
508         if (len > INT_MAX)
509                 return -EMSGSIZE;
510 
511         /* Mirror BSD error message compatibility */
512         if (msg->msg_flags & MSG_OOB)
513                 return -EOPNOTSUPP;
514 
515         /*
516          *      Get and verify the address.
517          */
518         memset(&fl6, 0, sizeof(fl6));
519 
520         fl6.flowi6_mark = sk->sk_mark;
521 
522         if (lsa) {
523                 if (addr_len < SIN6_LEN_RFC2133)
524                         return -EINVAL;
525 
526                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
527                         return -EAFNOSUPPORT;
528 
529                 daddr = &lsa->l2tp_addr;
530                 if (np->sndflow) {
531                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
532                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
533                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
534                                 if (flowlabel == NULL)
535                                         return -EINVAL;
536                         }
537                 }
538 
539                 /*
540                  * Otherwise it will be difficult to maintain
541                  * sk->sk_dst_cache.
542                  */
543                 if (sk->sk_state == TCP_ESTABLISHED &&
544                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
545                         daddr = &sk->sk_v6_daddr;
546 
547                 if (addr_len >= sizeof(struct sockaddr_in6) &&
548                     lsa->l2tp_scope_id &&
549                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
550                         fl6.flowi6_oif = lsa->l2tp_scope_id;
551         } else {
552                 if (sk->sk_state != TCP_ESTABLISHED)
553                         return -EDESTADDRREQ;
554 
555                 daddr = &sk->sk_v6_daddr;
556                 fl6.flowlabel = np->flow_label;
557         }
558 
559         if (fl6.flowi6_oif == 0)
560                 fl6.flowi6_oif = sk->sk_bound_dev_if;
561 
562         if (msg->msg_controllen) {
563                 opt = &opt_space;
564                 memset(opt, 0, sizeof(struct ipv6_txoptions));
565                 opt->tot_len = sizeof(struct ipv6_txoptions);
566 
567                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
568                                             &hlimit, &tclass, &dontfrag);
569                 if (err < 0) {
570                         fl6_sock_release(flowlabel);
571                         return err;
572                 }
573                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
574                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
575                         if (flowlabel == NULL)
576                                 return -EINVAL;
577                 }
578                 if (!(opt->opt_nflen|opt->opt_flen))
579                         opt = NULL;
580         }
581 
582         if (!opt) {
583                 opt = txopt_get(np);
584                 opt_to_free = opt;
585         }
586         if (flowlabel)
587                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
588         opt = ipv6_fixup_options(&opt_space, opt);
589 
590         fl6.flowi6_proto = sk->sk_protocol;
591         if (!ipv6_addr_any(daddr))
592                 fl6.daddr = *daddr;
593         else
594                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
595         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
596                 fl6.saddr = np->saddr;
597 
598         final_p = fl6_update_dst(&fl6, opt, &final);
599 
600         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
601                 fl6.flowi6_oif = np->mcast_oif;
602         else if (!fl6.flowi6_oif)
603                 fl6.flowi6_oif = np->ucast_oif;
604 
605         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
606 
607         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
608         if (IS_ERR(dst)) {
609                 err = PTR_ERR(dst);
610                 goto out;
611         }
612 
613         if (hlimit < 0)
614                 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
615 
616         if (tclass < 0)
617                 tclass = np->tclass;
618 
619         if (dontfrag < 0)
620                 dontfrag = np->dontfrag;
621 
622         if (msg->msg_flags & MSG_CONFIRM)
623                 goto do_confirm;
624 
625 back_from_confirm:
626         lock_sock(sk);
627         err = ip6_append_data(sk, ip_generic_getfrag, msg,
628                               ulen, transhdrlen, hlimit, tclass, opt,
629                               &fl6, (struct rt6_info *)dst,
630                               msg->msg_flags, dontfrag);
631         if (err)
632                 ip6_flush_pending_frames(sk);
633         else if (!(msg->msg_flags & MSG_MORE))
634                 err = l2tp_ip6_push_pending_frames(sk);
635         release_sock(sk);
636 done:
637         dst_release(dst);
638 out:
639         fl6_sock_release(flowlabel);
640         txopt_put(opt_to_free);
641 
642         return err < 0 ? err : len;
643 
644 do_confirm:
645         dst_confirm(dst);
646         if (!(msg->msg_flags & MSG_PROBE) || len)
647                 goto back_from_confirm;
648         err = 0;
649         goto done;
650 }
651 
652 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
653                             int noblock, int flags, int *addr_len)
654 {
655         struct ipv6_pinfo *np = inet6_sk(sk);
656         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
657         size_t copied = 0;
658         int err = -EOPNOTSUPP;
659         struct sk_buff *skb;
660 
661         if (flags & MSG_OOB)
662                 goto out;
663 
664         if (addr_len)
665                 *addr_len = sizeof(*lsa);
666 
667         if (flags & MSG_ERRQUEUE)
668                 return ipv6_recv_error(sk, msg, len, addr_len);
669 
670         skb = skb_recv_datagram(sk, flags, noblock, &err);
671         if (!skb)
672                 goto out;
673 
674         copied = skb->len;
675         if (len < copied) {
676                 msg->msg_flags |= MSG_TRUNC;
677                 copied = len;
678         }
679 
680         err = skb_copy_datagram_msg(skb, 0, msg, copied);
681         if (err)
682                 goto done;
683 
684         sock_recv_timestamp(msg, sk, skb);
685 
686         /* Copy the address. */
687         if (lsa) {
688                 lsa->l2tp_family = AF_INET6;
689                 lsa->l2tp_unused = 0;
690                 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
691                 lsa->l2tp_flowinfo = 0;
692                 lsa->l2tp_scope_id = 0;
693                 lsa->l2tp_conn_id = 0;
694                 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
695                         lsa->l2tp_scope_id = inet6_iif(skb);
696         }
697 
698         if (np->rxopt.all)
699                 ip6_datagram_recv_ctl(sk, msg, skb);
700 
701         if (flags & MSG_TRUNC)
702                 copied = skb->len;
703 done:
704         skb_free_datagram(sk, skb);
705 out:
706         return err ? err : copied;
707 }
708 
709 static struct proto l2tp_ip6_prot = {
710         .name              = "L2TP/IPv6",
711         .owner             = THIS_MODULE,
712         .init              = l2tp_ip6_open,
713         .close             = l2tp_ip6_close,
714         .bind              = l2tp_ip6_bind,
715         .connect           = l2tp_ip6_connect,
716         .disconnect        = l2tp_ip6_disconnect,
717         .ioctl             = udp_ioctl,
718         .destroy           = l2tp_ip6_destroy_sock,
719         .setsockopt        = ipv6_setsockopt,
720         .getsockopt        = ipv6_getsockopt,
721         .sendmsg           = l2tp_ip6_sendmsg,
722         .recvmsg           = l2tp_ip6_recvmsg,
723         .backlog_rcv       = l2tp_ip6_backlog_recv,
724         .hash              = inet6_hash,
725         .unhash            = inet_unhash,
726         .obj_size          = sizeof(struct l2tp_ip6_sock),
727 #ifdef CONFIG_COMPAT
728         .compat_setsockopt = compat_ipv6_setsockopt,
729         .compat_getsockopt = compat_ipv6_getsockopt,
730 #endif
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         .listen            = sock_no_listen,
745         .shutdown          = inet_shutdown,
746         .setsockopt        = sock_common_setsockopt,
747         .getsockopt        = sock_common_getsockopt,
748         .sendmsg           = inet_sendmsg,
749         .recvmsg           = sock_common_recvmsg,
750         .mmap              = sock_no_mmap,
751         .sendpage          = sock_no_sendpage,
752 #ifdef CONFIG_COMPAT
753         .compat_setsockopt = compat_sock_common_setsockopt,
754         .compat_getsockopt = compat_sock_common_getsockopt,
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 
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 
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 

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