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 (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(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 (!sock_flag(sk, SOCK_ZAPPED))
 298                 goto out_unlock;
 299
 300         if (sk->sk_state != TCP_CLOSE)
 301                 goto out_unlock;
 302
 303         /* Check if the address belongs to the host. */
 304         rcu_read_lock();
 305         if (addr_type != IPV6_ADDR_ANY) {
 306                 struct net_device *dev = NULL;
 307
 308                 if (addr_type & IPV6_ADDR_LINKLOCAL) {
 309                         if (addr_len >= sizeof(struct sockaddr_in6) &&
 310                             addr->l2tp_scope_id) {
 311                                 /* Override any existing binding, if another
 312                                  * one is supplied by user.
 313                                  */
 314                                 sk->sk_bound_dev_if = addr->l2tp_scope_id;
 315                         }
 316
 317                         /* Binding to link-local address requires an
 318                            interface */
 319                         if (!sk->sk_bound_dev_if)
 320                                 goto out_unlock_rcu;
 321
 322                         err = -ENODEV;
 323                         dev = dev_get_by_index_rcu(sock_net(sk),
 324                                                    sk->sk_bound_dev_if);
 325                         if (!dev)
 326                                 goto out_unlock_rcu;
 327                 }
 328
 329                 /* ipv4 addr of the socket is invalid.  Only the
 330                  * unspecified and mapped address have a v4 equivalent.
 331                  */
 332                 v4addr = LOOPBACK4_IPV6;
 333                 err = -EADDRNOTAVAIL;
 334                 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
 335                         goto out_unlock_rcu;
 336         }
 337         rcu_read_unlock();
 338
 339         inet->inet_rcv_saddr = inet->inet_saddr = v4addr;
 340         sk->sk_v6_rcv_saddr = addr->l2tp_addr;
 341         np->saddr = addr->l2tp_addr;
 342
 343         l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
 344
 345         write_lock_bh(&l2tp_ip6_lock);
 346         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 347         sk_del_node_init(sk);
 348         write_unlock_bh(&l2tp_ip6_lock);
 349
 350         sock_reset_flag(sk, SOCK_ZAPPED);
 351         release_sock(sk);
 352         return 0;
 353
 354 out_unlock_rcu:
 355         rcu_read_unlock();
 356 out_unlock:
 357         release_sock(sk);
 358         return err;
 359
 360 out_in_use:
 361         read_unlock_bh(&l2tp_ip6_lock);
 362         return err;
 363 }
 364
 365 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 366                             int addr_len)
 367 {
 368         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 369         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 370         struct in6_addr *daddr;
 371         int     addr_type;
 372         int rc;
 373
 374         if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
 375                 return -EINVAL;
 376
 377         if (addr_len < sizeof(*lsa))
 378                 return -EINVAL;
 379
 380         if (usin->sin6_family != AF_INET6)
 381                 return -EINVAL;
 382
 383         addr_type = ipv6_addr_type(&usin->sin6_addr);
 384         if (addr_type & IPV6_ADDR_MULTICAST)
 385                 return -EINVAL;
 386
 387         if (addr_type & IPV6_ADDR_MAPPED) {
 388                 daddr = &usin->sin6_addr;
 389                 if (ipv4_is_multicast(daddr->s6_addr32[3]))
 390                         return -EINVAL;
 391         }
 392
 393         rc = ip6_datagram_connect(sk, uaddr, addr_len);
 394
 395         lock_sock(sk);
 396
 397         l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 398
 399         write_lock_bh(&l2tp_ip6_lock);
 400         hlist_del_init(&sk->sk_bind_node);
 401         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 402         write_unlock_bh(&l2tp_ip6_lock);
 403
 404         release_sock(sk);
 405
 406         return rc;
 407 }
 408
 409 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 410 {
 411         if (sock_flag(sk, SOCK_ZAPPED))
 412                 return 0;
 413
 414         return __udp_disconnect(sk, flags);
 415 }
 416
 417 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 418                             int *uaddr_len, int peer)
 419 {
 420         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 421         struct sock *sk = sock->sk;
 422         struct ipv6_pinfo *np = inet6_sk(sk);
 423         struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 424
 425         lsa->l2tp_family = AF_INET6;
 426         lsa->l2tp_flowinfo = 0;
 427         lsa->l2tp_scope_id = 0;
 428         lsa->l2tp_unused = 0;
 429         if (peer) {
 430                 if (!lsk->peer_conn_id)
 431                         return -ENOTCONN;
 432                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 433                 lsa->l2tp_addr = sk->sk_v6_daddr;
 434                 if (np->sndflow)
 435                         lsa->l2tp_flowinfo = np->flow_label;
 436         } else {
 437                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 438                         lsa->l2tp_addr = np->saddr;
 439                 else
 440                         lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
 441
 442                 lsa->l2tp_conn_id = lsk->conn_id;
 443         }
 444         if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 445                 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 446         *uaddr_len = sizeof(*lsa);
 447         return 0;
 448 }
 449
 450 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 451 {
 452         int rc;
 453
 454         /* Charge it to the socket, dropping if the queue is full. */
 455         rc = sock_queue_rcv_skb(sk, skb);
 456         if (rc < 0)
 457                 goto drop;
 458
 459         return 0;
 460
 461 drop:
 462         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 463         kfree_skb(skb);
 464         return -1;
 465 }
 466
 467 static int l2tp_ip6_push_pending_frames(struct sock *sk)
 468 {
 469         struct sk_buff *skb;
 470         __be32 *transhdr = NULL;
 471         int err = 0;
 472
 473         skb = skb_peek(&sk->sk_write_queue);
 474         if (skb == NULL)
 475                 goto out;
 476
 477         transhdr = (__be32 *)skb_transport_header(skb);
 478         *transhdr = 0;
 479
 480         err = ip6_push_pending_frames(sk);
 481
 482 out:
 483         return err;
 484 }
 485
 486 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 487  * control frames.
 488  */
 489 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 490 {
 491         struct ipv6_txoptions opt_space;
 492         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 493         struct in6_addr *daddr, *final_p, final;
 494         struct ipv6_pinfo *np = inet6_sk(sk);
 495         struct ipv6_txoptions *opt_to_free = NULL;
 496         struct ipv6_txoptions *opt = NULL;
 497         struct ip6_flowlabel *flowlabel = NULL;
 498         struct dst_entry *dst = NULL;
 499         struct flowi6 fl6;
 500         struct sockcm_cookie sockc_unused = {0};
 501         struct ipcm6_cookie ipc6;
 502         int addr_len = msg->msg_namelen;
 503         int transhdrlen = 4; /* zero session-id */
 504         int ulen = len + transhdrlen;
 505         int err;
 506
 507         /* Rough check on arithmetic overflow,
 508            better check is made in ip6_append_data().
 509          */
 510         if (len > INT_MAX)
 511                 return -EMSGSIZE;
 512
 513         /* Mirror BSD error message compatibility */
 514         if (msg->msg_flags & MSG_OOB)
 515                 return -EOPNOTSUPP;
 516
 517         /*
 518          *      Get and verify the address.
 519          */
 520         memset(&fl6, 0, sizeof(fl6));
 521
 522         fl6.flowi6_mark = sk->sk_mark;
 523
 524         ipc6.hlimit = -1;
 525         ipc6.tclass = -1;
 526         ipc6.dontfrag = -1;
 527
 528         if (lsa) {
 529                 if (addr_len < SIN6_LEN_RFC2133)
 530                         return -EINVAL;
 531
 532                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 533                         return -EAFNOSUPPORT;
 534
 535                 daddr = &lsa->l2tp_addr;
 536                 if (np->sndflow) {
 537                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 538                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 539                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 540                                 if (flowlabel == NULL)
 541                                         return -EINVAL;
 542                         }
 543                 }
 544
 545                 /*
 546                  * Otherwise it will be difficult to maintain
 547                  * sk->sk_dst_cache.
 548                  */
 549                 if (sk->sk_state == TCP_ESTABLISHED &&
 550                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
 551                         daddr = &sk->sk_v6_daddr;
 552
 553                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 554                     lsa->l2tp_scope_id &&
 555                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 556                         fl6.flowi6_oif = lsa->l2tp_scope_id;
 557         } else {
 558                 if (sk->sk_state != TCP_ESTABLISHED)
 559                         return -EDESTADDRREQ;
 560
 561                 daddr = &sk->sk_v6_daddr;
 562                 fl6.flowlabel = np->flow_label;
 563         }
 564
 565         if (fl6.flowi6_oif == 0)
 566                 fl6.flowi6_oif = sk->sk_bound_dev_if;
 567
 568         if (msg->msg_controllen) {
 569                 opt = &opt_space;
 570                 memset(opt, 0, sizeof(struct ipv6_txoptions));
 571                 opt->tot_len = sizeof(struct ipv6_txoptions);
 572                 ipc6.opt = opt;
 573
 574                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6,
 575                                             &sockc_unused);
 576                 if (err < 0) {
 577                         fl6_sock_release(flowlabel);
 578                         return err;
 579                 }
 580                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 581                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 582                         if (flowlabel == NULL)
 583                                 return -EINVAL;
 584                 }
 585                 if (!(opt->opt_nflen|opt->opt_flen))
 586                         opt = NULL;
 587         }
 588
 589         if (!opt) {
 590                 opt = txopt_get(np);
 591                 opt_to_free = opt;
 592         }
 593         if (flowlabel)
 594                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
 595         opt = ipv6_fixup_options(&opt_space, opt);
 596         ipc6.opt = opt;
 597
 598         fl6.flowi6_proto = sk->sk_protocol;
 599         if (!ipv6_addr_any(daddr))
 600                 fl6.daddr = *daddr;
 601         else
 602                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 603         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 604                 fl6.saddr = np->saddr;
 605
 606         final_p = fl6_update_dst(&fl6, opt, &final);
 607
 608         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 609                 fl6.flowi6_oif = np->mcast_oif;
 610         else if (!fl6.flowi6_oif)
 611                 fl6.flowi6_oif = np->ucast_oif;
 612
 613         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 614
 615         if (ipc6.tclass < 0)
 616                 ipc6.tclass = np->tclass;
 617
 618         fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 619
 620         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 621         if (IS_ERR(dst)) {
 622                 err = PTR_ERR(dst);
 623                 goto out;
 624         }
 625
 626         if (ipc6.hlimit < 0)
 627                 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 628
 629         if (ipc6.dontfrag < 0)
 630                 ipc6.dontfrag = np->dontfrag;
 631
 632         if (msg->msg_flags & MSG_CONFIRM)
 633                 goto do_confirm;
 634
 635 back_from_confirm:
 636         lock_sock(sk);
 637         err = ip6_append_data(sk, ip_generic_getfrag, msg,
 638                               ulen, transhdrlen, &ipc6,
 639                               &fl6, (struct rt6_info *)dst,
 640                               msg->msg_flags, &sockc_unused);
 641         if (err)
 642                 ip6_flush_pending_frames(sk);
 643         else if (!(msg->msg_flags & MSG_MORE))
 644                 err = l2tp_ip6_push_pending_frames(sk);
 645         release_sock(sk);
 646 done:
 647         dst_release(dst);
 648 out:
 649         fl6_sock_release(flowlabel);
 650         txopt_put(opt_to_free);
 651
 652         return err < 0 ? err : len;
 653
 654 do_confirm:
 655         dst_confirm(dst);
 656         if (!(msg->msg_flags & MSG_PROBE) || len)
 657                 goto back_from_confirm;
 658         err = 0;
 659         goto done;
 660 }
 661
 662 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 663                             int noblock, int flags, int *addr_len)
 664 {
 665         struct ipv6_pinfo *np = inet6_sk(sk);
 666         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 667         size_t copied = 0;
 668         int err = -EOPNOTSUPP;
 669         struct sk_buff *skb;
 670
 671         if (flags & MSG_OOB)
 672                 goto out;
 673
 674         if (addr_len)
 675                 *addr_len = sizeof(*lsa);
 676
 677         if (flags & MSG_ERRQUEUE)
 678                 return ipv6_recv_error(sk, msg, len, addr_len);
 679
 680         skb = skb_recv_datagram(sk, flags, noblock, &err);
 681         if (!skb)
 682                 goto out;
 683
 684         copied = skb->len;
 685         if (len < copied) {
 686                 msg->msg_flags |= MSG_TRUNC;
 687                 copied = len;
 688         }
 689
 690         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 691         if (err)
 692                 goto done;
 693
 694         sock_recv_timestamp(msg, sk, skb);
 695
 696         /* Copy the address. */
 697         if (lsa) {
 698                 lsa->l2tp_family = AF_INET6;
 699                 lsa->l2tp_unused = 0;
 700                 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 701                 lsa->l2tp_flowinfo = 0;
 702                 lsa->l2tp_scope_id = 0;
 703                 lsa->l2tp_conn_id = 0;
 704                 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 705                         lsa->l2tp_scope_id = inet6_iif(skb);
 706         }
 707
 708         if (np->rxopt.all)
 709                 ip6_datagram_recv_ctl(sk, msg, skb);
 710
 711         if (flags & MSG_TRUNC)
 712                 copied = skb->len;
 713 done:
 714         skb_free_datagram(sk, skb);
 715 out:
 716         return err ? err : copied;
 717 }
 718
 719 static struct proto l2tp_ip6_prot = {
 720         .name              = "L2TP/IPv6",
 721         .owner             = THIS_MODULE,
 722         .init              = l2tp_ip6_open,
 723         .close             = l2tp_ip6_close,
 724         .bind              = l2tp_ip6_bind,
 725         .connect           = l2tp_ip6_connect,
 726         .disconnect        = l2tp_ip6_disconnect,
 727         .ioctl             = udp_ioctl,
 728         .destroy           = l2tp_ip6_destroy_sock,
 729         .setsockopt        = ipv6_setsockopt,
 730         .getsockopt        = ipv6_getsockopt,
 731         .sendmsg           = l2tp_ip6_sendmsg,
 732         .recvmsg           = l2tp_ip6_recvmsg,
 733         .backlog_rcv       = l2tp_ip6_backlog_recv,
 734         .hash              = inet6_hash,
 735         .unhash            = inet_unhash,
 736         .obj_size          = sizeof(struct l2tp_ip6_sock),
 737 #ifdef CONFIG_COMPAT
 738         .compat_setsockopt = compat_ipv6_setsockopt,
 739         .compat_getsockopt = compat_ipv6_getsockopt,
 740 #endif
 741 };
 742
 743 static const struct proto_ops l2tp_ip6_ops = {
 744         .family            = PF_INET6,
 745         .owner             = THIS_MODULE,
 746         .release           = inet6_release,
 747         .bind              = inet6_bind,
 748         .connect           = inet_dgram_connect,
 749         .socketpair        = sock_no_socketpair,
 750         .accept            = sock_no_accept,
 751         .getname           = l2tp_ip6_getname,
 752         .poll              = datagram_poll,
 753         .ioctl             = inet6_ioctl,
 754         .listen            = sock_no_listen,
 755         .shutdown          = inet_shutdown,
 756         .setsockopt        = sock_common_setsockopt,
 757         .getsockopt        = sock_common_getsockopt,
 758         .sendmsg           = inet_sendmsg,
 759         .recvmsg           = sock_common_recvmsg,
 760         .mmap              = sock_no_mmap,
 761         .sendpage          = sock_no_sendpage,
 762 #ifdef CONFIG_COMPAT
 763         .compat_setsockopt = compat_sock_common_setsockopt,
 764         .compat_getsockopt = compat_sock_common_getsockopt,
 765 #endif
 766 };
 767
 768 static struct inet_protosw l2tp_ip6_protosw = {
 769         .type           = SOCK_DGRAM,
 770         .protocol       = IPPROTO_L2TP,
 771         .prot           = &l2tp_ip6_prot,
 772         .ops            = &l2tp_ip6_ops,
 773 };
 774
 775 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 776         .handler        = l2tp_ip6_recv,
 777 };
 778
 779 static int __init l2tp_ip6_init(void)
 780 {
 781         int err;
 782
 783         pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 784
 785         err = proto_register(&l2tp_ip6_prot, 1);
 786         if (err != 0)
 787                 goto out;
 788
 789         err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 790         if (err)
 791                 goto out1;
 792
 793         inet6_register_protosw(&l2tp_ip6_protosw);
 794         return 0;
 795
 796 out1:
 797         proto_unregister(&l2tp_ip6_prot);
 798 out:
 799         return err;
 800 }
 801
 802 static void __exit l2tp_ip6_exit(void)
 803 {
 804         inet6_unregister_protosw(&l2tp_ip6_protosw);
 805         inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 806         proto_unregister(&l2tp_ip6_prot);
 807 }
 808
 809 module_init(l2tp_ip6_init);
 810 module_exit(l2tp_ip6_exit);
 811
 812 MODULE_LICENSE("GPL");
 813 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 814 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 815 MODULE_VERSION("1.0");
 816
 817 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 818  * enums
 819  */
 820 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
 821 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);