net/l2tp/l2tp_ip6.c

   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 net *net = dev_net(skb->dev);
 132         struct sock *sk;
 133         u32 session_id;
 134         u32 tunnel_id;
 135         unsigned char *ptr, *optr;
 136         struct l2tp_session *session;
 137         struct l2tp_tunnel *tunnel = NULL;
 138         int length;
 139
 140         if (!pskb_may_pull(skb, 4))
 141                 goto discard;
 142
 143         /* Point to L2TP header */
 144         optr = ptr = skb->data;
 145         session_id = ntohl(*((__be32 *) ptr));
 146         ptr += 4;
 147
 148         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 149          * the session_id. If it is 0, the packet is a L2TP control
 150          * frame and the session_id value can be discarded.
 151          */
 152         if (session_id == 0) {
 153                 __skb_pull(skb, 4);
 154                 goto pass_up;
 155         }
 156
 157         /* Ok, this is a data packet. Lookup the session. */
 158         session = l2tp_session_find(net, NULL, session_id);
 159         if (session == NULL)
 160                 goto discard;
 161
 162         tunnel = session->tunnel;
 163         if (tunnel == NULL)
 164                 goto discard;
 165
 166         /* Trace packet contents, if enabled */
 167         if (tunnel->debug & L2TP_MSG_DATA) {
 168                 length = min(32u, skb->len);
 169                 if (!pskb_may_pull(skb, length))
 170                         goto discard;
 171
 172                 /* Point to L2TP header */
 173                 optr = ptr = skb->data;
 174                 ptr += 4;
 175                 pr_debug("%s: ip recv\n", tunnel->name);
 176                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 177         }
 178
 179         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
 180                          tunnel->recv_payload_hook);
 181         return 0;
 182
 183 pass_up:
 184         /* Get the tunnel_id from the L2TP header */
 185         if (!pskb_may_pull(skb, 12))
 186                 goto discard;
 187
 188         if ((skb->data[0] & 0xc0) != 0xc0)
 189                 goto discard;
 190
 191         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 192         tunnel = l2tp_tunnel_find(net, tunnel_id);
 193         if (tunnel != NULL)
 194                 sk = tunnel->sock;
 195         else {
 196                 struct ipv6hdr *iph = ipv6_hdr(skb);
 197
 198                 read_lock_bh(&l2tp_ip6_lock);
 199                 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr,
 200                                             0, tunnel_id);
 201                 read_unlock_bh(&l2tp_ip6_lock);
 202         }
 203
 204         if (sk == NULL)
 205                 goto discard;
 206
 207         sock_hold(sk);
 208
 209         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 210                 goto discard_put;
 211
 212         nf_reset(skb);
 213
 214         return sk_receive_skb(sk, skb, 1);
 215
 216 discard_put:
 217         sock_put(sk);
 218
 219 discard:
 220         kfree_skb(skb);
 221         return 0;
 222 }
 223
 224 static int l2tp_ip6_open(struct sock *sk)
 225 {
 226         /* Prevent autobind. We don't have ports. */
 227         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 228
 229         write_lock_bh(&l2tp_ip6_lock);
 230         sk_add_node(sk, &l2tp_ip6_table);
 231         write_unlock_bh(&l2tp_ip6_lock);
 232
 233         return 0;
 234 }
 235
 236 static void l2tp_ip6_close(struct sock *sk, long timeout)
 237 {
 238         write_lock_bh(&l2tp_ip6_lock);
 239         hlist_del_init(&sk->sk_bind_node);
 240         sk_del_node_init(sk);
 241         write_unlock_bh(&l2tp_ip6_lock);
 242
 243         sk_common_release(sk);
 244 }
 245
 246 static void l2tp_ip6_destroy_sock(struct sock *sk)
 247 {
 248         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 249
 250         lock_sock(sk);
 251         ip6_flush_pending_frames(sk);
 252         release_sock(sk);
 253
 254         if (tunnel) {
 255                 l2tp_tunnel_closeall(tunnel);
 256                 sock_put(sk);
 257         }
 258
 259         inet6_destroy_sock(sk);
 260 }
 261
 262 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 263 {
 264         struct inet_sock *inet = inet_sk(sk);
 265         struct ipv6_pinfo *np = inet6_sk(sk);
 266         struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
 267         struct net *net = sock_net(sk);
 268         __be32 v4addr = 0;
 269         int addr_type;
 270         int err;
 271
 272         if (!sock_flag(sk, SOCK_ZAPPED))
 273                 return -EINVAL;
 274         if (addr->l2tp_family != AF_INET6)
 275                 return -EINVAL;
 276         if (addr_len < sizeof(*addr))
 277                 return -EINVAL;
 278
 279         addr_type = ipv6_addr_type(&addr->l2tp_addr);
 280
 281         /* l2tp_ip6 sockets are IPv6 only */
 282         if (addr_type == IPV6_ADDR_MAPPED)
 283                 return -EADDRNOTAVAIL;
 284
 285         /* L2TP is point-point, not multicast */
 286         if (addr_type & IPV6_ADDR_MULTICAST)
 287                 return -EADDRNOTAVAIL;
 288
 289         err = -EADDRINUSE;
 290         read_lock_bh(&l2tp_ip6_lock);
 291         if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr,
 292                                    sk->sk_bound_dev_if, addr->l2tp_conn_id))
 293                 goto out_in_use;
 294         read_unlock_bh(&l2tp_ip6_lock);
 295
 296         lock_sock(sk);
 297
 298         err = -EINVAL;
 299         if (sk->sk_state != TCP_CLOSE)
 300                 goto out_unlock;
 301
 302         /* Check if the address belongs to the host. */
 303         rcu_read_lock();
 304         if (addr_type != IPV6_ADDR_ANY) {
 305                 struct net_device *dev = NULL;
 306
 307                 if (addr_type & IPV6_ADDR_LINKLOCAL) {
 308                         if (addr_len >= sizeof(struct sockaddr_in6) &&
 309                             addr->l2tp_scope_id) {
 310                                 /* Override any existing binding, if another
 311                                  * one is supplied by user.
 312                                  */
 313                                 sk->sk_bound_dev_if = addr->l2tp_scope_id;
 314                         }
 315
 316                         /* Binding to link-local address requires an
 317                            interface */
 318                         if (!sk->sk_bound_dev_if)
 319                                 goto out_unlock_rcu;
 320
 321                         err = -ENODEV;
 322                         dev = dev_get_by_index_rcu(sock_net(sk),
 323                                                    sk->sk_bound_dev_if);
 324                         if (!dev)
 325                                 goto out_unlock_rcu;
 326                 }
 327
 328                 /* ipv4 addr of the socket is invalid.  Only the
 329                  * unspecified and mapped address have a v4 equivalent.
 330                  */
 331                 v4addr = LOOPBACK4_IPV6;
 332                 err = -EADDRNOTAVAIL;
 333                 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
 334                         goto out_unlock_rcu;
 335         }
 336         rcu_read_unlock();
 337
 338         inet->inet_rcv_saddr = inet->inet_saddr = v4addr;
 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         write_lock_bh(&l2tp_ip6_lock);
 345         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 346         sk_del_node_init(sk);
 347         write_unlock_bh(&l2tp_ip6_lock);
 348
 349         sock_reset_flag(sk, SOCK_ZAPPED);
 350         release_sock(sk);
 351         return 0;
 352
 353 out_unlock_rcu:
 354         rcu_read_unlock();
 355 out_unlock:
 356         release_sock(sk);
 357         return err;
 358
 359 out_in_use:
 360         read_unlock_bh(&l2tp_ip6_lock);
 361         return err;
 362 }
 363
 364 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 365                             int addr_len)
 366 {
 367         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 368         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 369         struct in6_addr *daddr;
 370         int     addr_type;
 371         int rc;
 372
 373         if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
 374                 return -EINVAL;
 375
 376         if (addr_len < sizeof(*lsa))
 377                 return -EINVAL;
 378
 379         if (usin->sin6_family != AF_INET6)
 380                 return -EINVAL;
 381
 382         addr_type = ipv6_addr_type(&usin->sin6_addr);
 383         if (addr_type & IPV6_ADDR_MULTICAST)
 384                 return -EINVAL;
 385
 386         if (addr_type & IPV6_ADDR_MAPPED) {
 387                 daddr = &usin->sin6_addr;
 388                 if (ipv4_is_multicast(daddr->s6_addr32[3]))
 389                         return -EINVAL;
 390         }
 391
 392         rc = ip6_datagram_connect(sk, uaddr, addr_len);
 393
 394         lock_sock(sk);
 395
 396         l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 397
 398         write_lock_bh(&l2tp_ip6_lock);
 399         hlist_del_init(&sk->sk_bind_node);
 400         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 401         write_unlock_bh(&l2tp_ip6_lock);
 402
 403         release_sock(sk);
 404
 405         return rc;
 406 }
 407
 408 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 409 {
 410         if (sock_flag(sk, SOCK_ZAPPED))
 411                 return 0;
 412
 413         return udp_disconnect(sk, flags);
 414 }
 415
 416 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 417                             int *uaddr_len, int peer)
 418 {
 419         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 420         struct sock *sk = sock->sk;
 421         struct ipv6_pinfo *np = inet6_sk(sk);
 422         struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 423
 424         lsa->l2tp_family = AF_INET6;
 425         lsa->l2tp_flowinfo = 0;
 426         lsa->l2tp_scope_id = 0;
 427         lsa->l2tp_unused = 0;
 428         if (peer) {
 429                 if (!lsk->peer_conn_id)
 430                         return -ENOTCONN;
 431                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 432                 lsa->l2tp_addr = sk->sk_v6_daddr;
 433                 if (np->sndflow)
 434                         lsa->l2tp_flowinfo = np->flow_label;
 435         } else {
 436                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 437                         lsa->l2tp_addr = np->saddr;
 438                 else
 439                         lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
 440
 441                 lsa->l2tp_conn_id = lsk->conn_id;
 442         }
 443         if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 444                 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 445         *uaddr_len = sizeof(*lsa);
 446         return 0;
 447 }
 448
 449 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 450 {
 451         int rc;
 452
 453         /* Charge it to the socket, dropping if the queue is full. */
 454         rc = sock_queue_rcv_skb(sk, skb);
 455         if (rc < 0)
 456                 goto drop;
 457
 458         return 0;
 459
 460 drop:
 461         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 462         kfree_skb(skb);
 463         return -1;
 464 }
 465
 466 static int l2tp_ip6_push_pending_frames(struct sock *sk)
 467 {
 468         struct sk_buff *skb;
 469         __be32 *transhdr = NULL;
 470         int err = 0;
 471
 472         skb = skb_peek(&sk->sk_write_queue);
 473         if (skb == NULL)
 474                 goto out;
 475
 476         transhdr = (__be32 *)skb_transport_header(skb);
 477         *transhdr = 0;
 478
 479         err = ip6_push_pending_frames(sk);
 480
 481 out:
 482         return err;
 483 }
 484
 485 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 486  * control frames.
 487  */
 488 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 489 {
 490         struct ipv6_txoptions opt_space;
 491         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 492         struct in6_addr *daddr, *final_p, final;
 493         struct ipv6_pinfo *np = inet6_sk(sk);
 494         struct ipv6_txoptions *opt_to_free = NULL;
 495         struct ipv6_txoptions *opt = NULL;
 496         struct ip6_flowlabel *flowlabel = NULL;
 497         struct dst_entry *dst = NULL;
 498         struct flowi6 fl6;
 499         struct sockcm_cookie sockc_unused = {0};
 500         struct ipcm6_cookie ipc6;
 501         int addr_len = msg->msg_namelen;
 502         int transhdrlen = 4; /* zero session-id */
 503         int ulen = len + transhdrlen;
 504         int err;
 505
 506         /* Rough check on arithmetic overflow,
 507            better check is made in ip6_append_data().
 508          */
 509         if (len > INT_MAX)
 510                 return -EMSGSIZE;
 511
 512         /* Mirror BSD error message compatibility */
 513         if (msg->msg_flags & MSG_OOB)
 514                 return -EOPNOTSUPP;
 515
 516         /*
 517          *      Get and verify the address.
 518          */
 519         memset(&fl6, 0, sizeof(fl6));
 520
 521         fl6.flowi6_mark = sk->sk_mark;
 522
 523         ipc6.hlimit = -1;
 524         ipc6.tclass = -1;
 525         ipc6.dontfrag = -1;
 526
 527         if (lsa) {
 528                 if (addr_len < SIN6_LEN_RFC2133)
 529                         return -EINVAL;
 530
 531                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 532                         return -EAFNOSUPPORT;
 533
 534                 daddr = &lsa->l2tp_addr;
 535                 if (np->sndflow) {
 536                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 537                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 538                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 539                                 if (flowlabel == NULL)
 540                                         return -EINVAL;
 541                         }
 542                 }
 543
 544                 /*
 545                  * Otherwise it will be difficult to maintain
 546                  * sk->sk_dst_cache.
 547                  */
 548                 if (sk->sk_state == TCP_ESTABLISHED &&
 549                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
 550                         daddr = &sk->sk_v6_daddr;
 551
 552                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 553                     lsa->l2tp_scope_id &&
 554                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 555                         fl6.flowi6_oif = lsa->l2tp_scope_id;
 556         } else {
 557                 if (sk->sk_state != TCP_ESTABLISHED)
 558                         return -EDESTADDRREQ;
 559
 560                 daddr = &sk->sk_v6_daddr;
 561                 fl6.flowlabel = np->flow_label;
 562         }
 563
 564         if (fl6.flowi6_oif == 0)
 565                 fl6.flowi6_oif = sk->sk_bound_dev_if;
 566
 567         if (msg->msg_controllen) {
 568                 opt = &opt_space;
 569                 memset(opt, 0, sizeof(struct ipv6_txoptions));
 570                 opt->tot_len = sizeof(struct ipv6_txoptions);
 571                 ipc6.opt = opt;
 572
 573                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6,
 574                                             &sockc_unused);
 575                 if (err < 0) {
 576                         fl6_sock_release(flowlabel);
 577                         return err;
 578                 }
 579                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 580                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 581                         if (flowlabel == NULL)
 582                                 return -EINVAL;
 583                 }
 584                 if (!(opt->opt_nflen|opt->opt_flen))
 585                         opt = NULL;
 586         }
 587
 588         if (!opt) {
 589                 opt = txopt_get(np);
 590                 opt_to_free = opt;
 591         }
 592         if (flowlabel)
 593                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
 594         opt = ipv6_fixup_options(&opt_space, opt);
 595         ipc6.opt = opt;
 596
 597         fl6.flowi6_proto = sk->sk_protocol;
 598         if (!ipv6_addr_any(daddr))
 599                 fl6.daddr = *daddr;
 600         else
 601                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 602         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 603                 fl6.saddr = np->saddr;
 604
 605         final_p = fl6_update_dst(&fl6, opt, &final);
 606
 607         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 608                 fl6.flowi6_oif = np->mcast_oif;
 609         else if (!fl6.flowi6_oif)
 610                 fl6.flowi6_oif = np->ucast_oif;
 611
 612         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 613
 614         if (ipc6.tclass < 0)
 615                 ipc6.tclass = np->tclass;
 616
 617         fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 618
 619         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 620         if (IS_ERR(dst)) {
 621                 err = PTR_ERR(dst);
 622                 goto out;
 623         }
 624
 625         if (ipc6.hlimit < 0)
 626                 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 627
 628         if (ipc6.dontfrag < 0)
 629                 ipc6.dontfrag = np->dontfrag;
 630
 631         if (msg->msg_flags & MSG_CONFIRM)
 632                 goto do_confirm;
 633
 634 back_from_confirm:
 635         lock_sock(sk);
 636         err = ip6_append_data(sk, ip_generic_getfrag, msg,
 637                               ulen, transhdrlen, &ipc6,
 638                               &fl6, (struct rt6_info *)dst,
 639                               msg->msg_flags, &sockc_unused);
 640         if (err)
 641                 ip6_flush_pending_frames(sk);
 642         else if (!(msg->msg_flags & MSG_MORE))
 643                 err = l2tp_ip6_push_pending_frames(sk);
 644         release_sock(sk);
 645 done:
 646         dst_release(dst);
 647 out:
 648         fl6_sock_release(flowlabel);
 649         txopt_put(opt_to_free);
 650
 651         return err < 0 ? err : len;
 652
 653 do_confirm:
 654         dst_confirm(dst);
 655         if (!(msg->msg_flags & MSG_PROBE) || len)
 656                 goto back_from_confirm;
 657         err = 0;
 658         goto done;
 659 }
 660
 661 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 662                             int noblock, int flags, int *addr_len)
 663 {
 664         struct ipv6_pinfo *np = inet6_sk(sk);
 665         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 666         size_t copied = 0;
 667         int err = -EOPNOTSUPP;
 668         struct sk_buff *skb;
 669
 670         if (flags & MSG_OOB)
 671                 goto out;
 672
 673         if (addr_len)
 674                 *addr_len = sizeof(*lsa);
 675
 676         if (flags & MSG_ERRQUEUE)
 677                 return ipv6_recv_error(sk, msg, len, addr_len);
 678
 679         skb = skb_recv_datagram(sk, flags, noblock, &err);
 680         if (!skb)
 681                 goto out;
 682
 683         copied = skb->len;
 684         if (len < copied) {
 685                 msg->msg_flags |= MSG_TRUNC;
 686                 copied = len;
 687         }
 688
 689         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 690         if (err)
 691                 goto done;
 692
 693         sock_recv_timestamp(msg, sk, skb);
 694
 695         /* Copy the address. */
 696         if (lsa) {
 697                 lsa->l2tp_family = AF_INET6;
 698                 lsa->l2tp_unused = 0;
 699                 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 700                 lsa->l2tp_flowinfo = 0;
 701                 lsa->l2tp_scope_id = 0;
 702                 lsa->l2tp_conn_id = 0;
 703                 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 704                         lsa->l2tp_scope_id = inet6_iif(skb);
 705         }
 706
 707         if (np->rxopt.all)
 708                 ip6_datagram_recv_ctl(sk, msg, skb);
 709
 710         if (flags & MSG_TRUNC)
 711                 copied = skb->len;
 712 done:
 713         skb_free_datagram(sk, skb);
 714 out:
 715         return err ? err : copied;
 716 }
 717
 718 static struct proto l2tp_ip6_prot = {
 719         .name              = "L2TP/IPv6",
 720         .owner             = THIS_MODULE,
 721         .init              = l2tp_ip6_open,
 722         .close             = l2tp_ip6_close,
 723         .bind              = l2tp_ip6_bind,
 724         .connect           = l2tp_ip6_connect,
 725         .disconnect        = l2tp_ip6_disconnect,
 726         .ioctl             = udp_ioctl,
 727         .destroy           = l2tp_ip6_destroy_sock,
 728         .setsockopt        = ipv6_setsockopt,
 729         .getsockopt        = ipv6_getsockopt,
 730         .sendmsg           = l2tp_ip6_sendmsg,
 731         .recvmsg           = l2tp_ip6_recvmsg,
 732         .backlog_rcv       = l2tp_ip6_backlog_recv,
 733         .hash              = inet6_hash,
 734         .unhash            = inet_unhash,
 735         .obj_size          = sizeof(struct l2tp_ip6_sock),
 736 #ifdef CONFIG_COMPAT
 737         .compat_setsockopt = compat_ipv6_setsockopt,
 738         .compat_getsockopt = compat_ipv6_getsockopt,
 739 #endif
 740 };
 741
 742 static const struct proto_ops l2tp_ip6_ops = {
 743         .family            = PF_INET6,
 744         .owner             = THIS_MODULE,
 745         .release           = inet6_release,
 746         .bind              = inet6_bind,
 747         .connect           = inet_dgram_connect,
 748         .socketpair        = sock_no_socketpair,
 749         .accept            = sock_no_accept,
 750         .getname           = l2tp_ip6_getname,
 751         .poll              = datagram_poll,
 752         .ioctl             = inet6_ioctl,
 753         .listen            = sock_no_listen,
 754         .shutdown          = inet_shutdown,
 755         .setsockopt        = sock_common_setsockopt,
 756         .getsockopt        = sock_common_getsockopt,
 757         .sendmsg           = inet_sendmsg,
 758         .recvmsg           = sock_common_recvmsg,
 759         .mmap              = sock_no_mmap,
 760         .sendpage          = sock_no_sendpage,
 761 #ifdef CONFIG_COMPAT
 762         .compat_setsockopt = compat_sock_common_setsockopt,
 763         .compat_getsockopt = compat_sock_common_getsockopt,
 764 #endif
 765 };
 766
 767 static struct inet_protosw l2tp_ip6_protosw = {
 768         .type           = SOCK_DGRAM,
 769         .protocol       = IPPROTO_L2TP,
 770         .prot           = &l2tp_ip6_prot,
 771         .ops            = &l2tp_ip6_ops,
 772 };
 773
 774 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 775         .handler        = l2tp_ip6_recv,
 776 };
 777
 778 static int __init l2tp_ip6_init(void)
 779 {
 780         int err;
 781
 782         pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 783
 784         err = proto_register(&l2tp_ip6_prot, 1);
 785         if (err != 0)
 786                 goto out;
 787
 788         err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 789         if (err)
 790                 goto out1;
 791
 792         inet6_register_protosw(&l2tp_ip6_protosw);
 793         return 0;
 794
 795 out1:
 796         proto_unregister(&l2tp_ip6_prot);
 797 out:
 798         return err;
 799 }
 800
 801 static void __exit l2tp_ip6_exit(void)
 802 {
 803         inet6_unregister_protosw(&l2tp_ip6_protosw);
 804         inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 805         proto_unregister(&l2tp_ip6_prot);
 806 }
 807
 808 module_init(l2tp_ip6_init);
 809 module_exit(l2tp_ip6_exit);
 810
 811 MODULE_LICENSE("GPL");
 812 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 813 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 814 MODULE_VERSION("1.0");
 815
 816 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 817  * enums
 818  */
 819 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
 820 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);