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/tcp_states.h>
  29 #include <net/protocol.h>
  30 #include <net/xfrm.h>
  31
  32 #include <net/transp_v6.h>
  33 #include <net/addrconf.h>
  34 #include <net/ip6_route.h>
  35
  36 #include "l2tp_core.h"
  37
  38 struct l2tp_ip6_sock {
  39         /* inet_sock has to be the first member of l2tp_ip6_sock */
  40         struct inet_sock        inet;
  41
  42         u32                     conn_id;
  43         u32                     peer_conn_id;
  44
  45         /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
  46            inet6_sk_generic */
  47         struct ipv6_pinfo       inet6;
  48 };
  49
  50 static DEFINE_RWLOCK(l2tp_ip6_lock);
  51 static struct hlist_head l2tp_ip6_table;
  52 static struct hlist_head l2tp_ip6_bind_table;
  53
  54 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
  55 {
  56         return (struct l2tp_ip6_sock *)sk;
  57 }
  58
  59 static struct sock *__l2tp_ip6_bind_lookup(struct net *net,
  60                                            struct in6_addr *laddr,
  61                                            int dif, u32 tunnel_id)
  62 {
  63         struct sock *sk;
  64
  65         sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
  66                 const struct in6_addr *addr = inet6_rcv_saddr(sk);
  67                 struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
  68
  69                 if (l2tp == NULL)
  70                         continue;
  71
  72                 if ((l2tp->conn_id == tunnel_id) &&
  73                     net_eq(sock_net(sk), net) &&
  74                     !(addr && ipv6_addr_equal(addr, laddr)) &&
  75                     !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
  76                         goto found;
  77         }
  78
  79         sk = NULL;
  80 found:
  81         return sk;
  82 }
  83
  84 static inline struct sock *l2tp_ip6_bind_lookup(struct net *net,
  85                                                 struct in6_addr *laddr,
  86                                                 int dif, u32 tunnel_id)
  87 {
  88         struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id);
  89         if (sk)
  90                 sock_hold(sk);
  91
  92         return sk;
  93 }
  94
  95 /* When processing receive frames, there are two cases to
  96  * consider. Data frames consist of a non-zero session-id and an
  97  * optional cookie. Control frames consist of a regular L2TP header
  98  * preceded by 32-bits of zeros.
  99  *
 100  * L2TPv3 Session Header Over IP
 101  *
 102  *  0                   1                   2                   3
 103  *  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
 104  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 105  * |                           Session ID                          |
 106  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 107  * |               Cookie (optional, maximum 64 bits)...
 108  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 109  *                                                                 |
 110  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 111  *
 112  * L2TPv3 Control Message Header Over IP
 113  *
 114  *  0                   1                   2                   3
 115  *  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
 116  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 117  * |                      (32 bits of zeros)                       |
 118  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 119  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 120  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 121  * |                     Control Connection ID                     |
 122  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 123  * |               Ns              |               Nr              |
 124  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 125  *
 126  * All control frames are passed to userspace.
 127  */
 128 static int l2tp_ip6_recv(struct sk_buff *skb)
 129 {
 130         struct sock *sk;
 131         u32 session_id;
 132         u32 tunnel_id;
 133         unsigned char *ptr, *optr;
 134         struct l2tp_session *session;
 135         struct l2tp_tunnel *tunnel = NULL;
 136         int length;
 137
 138         if (!pskb_may_pull(skb, 4))
 139                 goto discard;
 140
 141         /* Point to L2TP header */
 142         optr = ptr = skb->data;
 143         session_id = ntohl(*((__be32 *) ptr));
 144         ptr += 4;
 145
 146         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 147          * the session_id. If it is 0, the packet is a L2TP control
 148          * frame and the session_id value can be discarded.
 149          */
 150         if (session_id == 0) {
 151                 __skb_pull(skb, 4);
 152                 goto pass_up;
 153         }
 154
 155         /* Ok, this is a data packet. Lookup the session. */
 156         session = l2tp_session_find(&init_net, NULL, session_id);
 157         if (session == NULL)
 158                 goto discard;
 159
 160         tunnel = session->tunnel;
 161         if (tunnel == NULL)
 162                 goto discard;
 163
 164         /* Trace packet contents, if enabled */
 165         if (tunnel->debug & L2TP_MSG_DATA) {
 166                 length = min(32u, skb->len);
 167                 if (!pskb_may_pull(skb, length))
 168                         goto discard;
 169
 170                 /* Point to L2TP header */
 171                 optr = ptr = skb->data;
 172                 ptr += 4;
 173                 pr_debug("%s: ip recv\n", tunnel->name);
 174                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 175         }
 176
 177         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
 178                          tunnel->recv_payload_hook);
 179         return 0;
 180
 181 pass_up:
 182         /* Get the tunnel_id from the L2TP header */
 183         if (!pskb_may_pull(skb, 12))
 184                 goto discard;
 185
 186         if ((skb->data[0] & 0xc0) != 0xc0)
 187                 goto discard;
 188
 189         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 190         tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
 191         if (tunnel) {
 192                 sk = tunnel->sock;
 193                 sock_hold(sk);
 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                 if (!sk) {
 201                         read_unlock_bh(&l2tp_ip6_lock);
 202                         goto discard;
 203                 }
 204
 205                 sock_hold(sk);
 206                 read_unlock_bh(&l2tp_ip6_lock);
 207         }
 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         __be32 v4addr = 0;
 268         int addr_type;
 269         int err;
 270
 271         if (addr->l2tp_family != AF_INET6)
 272                 return -EINVAL;
 273         if (addr_len < sizeof(*addr))
 274                 return -EINVAL;
 275
 276         addr_type = ipv6_addr_type(&addr->l2tp_addr);
 277
 278         /* l2tp_ip6 sockets are IPv6 only */
 279         if (addr_type == IPV6_ADDR_MAPPED)
 280                 return -EADDRNOTAVAIL;
 281
 282         /* L2TP is point-point, not multicast */
 283         if (addr_type & IPV6_ADDR_MULTICAST)
 284                 return -EADDRNOTAVAIL;
 285
 286         err = -EADDRINUSE;
 287         read_lock_bh(&l2tp_ip6_lock);
 288         if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr,
 289                                    sk->sk_bound_dev_if, addr->l2tp_conn_id))
 290                 goto out_in_use;
 291         read_unlock_bh(&l2tp_ip6_lock);
 292
 293         lock_sock(sk);
 294
 295         err = -EINVAL;
 296         if (!sock_flag(sk, SOCK_ZAPPED))
 297                 goto out_unlock;
 298
 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(&init_net, 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         int addr_len = msg->msg_namelen;
 500         int hlimit = -1;
 501         int tclass = -1;
 502         int dontfrag = -1;
 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         if (lsa) {
 525                 if (addr_len < SIN6_LEN_RFC2133)
 526                         return -EINVAL;
 527
 528                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 529                         return -EAFNOSUPPORT;
 530
 531                 daddr = &lsa->l2tp_addr;
 532                 if (np->sndflow) {
 533                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 534                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 535                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 536                                 if (flowlabel == NULL)
 537                                         return -EINVAL;
 538                         }
 539                 }
 540
 541                 /*
 542                  * Otherwise it will be difficult to maintain
 543                  * sk->sk_dst_cache.
 544                  */
 545                 if (sk->sk_state == TCP_ESTABLISHED &&
 546                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
 547                         daddr = &sk->sk_v6_daddr;
 548
 549                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 550                     lsa->l2tp_scope_id &&
 551                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 552                         fl6.flowi6_oif = lsa->l2tp_scope_id;
 553         } else {
 554                 if (sk->sk_state != TCP_ESTABLISHED)
 555                         return -EDESTADDRREQ;
 556
 557                 daddr = &sk->sk_v6_daddr;
 558                 fl6.flowlabel = np->flow_label;
 559         }
 560
 561         if (fl6.flowi6_oif == 0)
 562                 fl6.flowi6_oif = sk->sk_bound_dev_if;
 563
 564         if (msg->msg_controllen) {
 565                 opt = &opt_space;
 566                 memset(opt, 0, sizeof(struct ipv6_txoptions));
 567                 opt->tot_len = sizeof(struct ipv6_txoptions);
 568
 569                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
 570                                             &hlimit, &tclass, &dontfrag);
 571                 if (err < 0) {
 572                         fl6_sock_release(flowlabel);
 573                         return err;
 574                 }
 575                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 576                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 577                         if (flowlabel == NULL)
 578                                 return -EINVAL;
 579                 }
 580                 if (!(opt->opt_nflen|opt->opt_flen))
 581                         opt = NULL;
 582         }
 583
 584         if (!opt) {
 585                 opt = txopt_get(np);
 586                 opt_to_free = opt;
 587         }
 588         if (flowlabel)
 589                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
 590         opt = ipv6_fixup_options(&opt_space, opt);
 591
 592         fl6.flowi6_proto = sk->sk_protocol;
 593         if (!ipv6_addr_any(daddr))
 594                 fl6.daddr = *daddr;
 595         else
 596                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 597         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 598                 fl6.saddr = np->saddr;
 599
 600         final_p = fl6_update_dst(&fl6, opt, &final);
 601
 602         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 603                 fl6.flowi6_oif = np->mcast_oif;
 604         else if (!fl6.flowi6_oif)
 605                 fl6.flowi6_oif = np->ucast_oif;
 606
 607         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 608
 609         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 610         if (IS_ERR(dst)) {
 611                 err = PTR_ERR(dst);
 612                 goto out;
 613         }
 614
 615         if (hlimit < 0)
 616                 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 617
 618         if (tclass < 0)
 619                 tclass = np->tclass;
 620
 621         if (dontfrag < 0)
 622                 dontfrag = np->dontfrag;
 623
 624         if (msg->msg_flags & MSG_CONFIRM)
 625                 goto do_confirm;
 626
 627 back_from_confirm:
 628         lock_sock(sk);
 629         err = ip6_append_data(sk, ip_generic_getfrag, msg,
 630                               ulen, transhdrlen, hlimit, tclass, opt,
 631                               &fl6, (struct rt6_info *)dst,
 632                               msg->msg_flags, dontfrag);
 633         if (err)
 634                 ip6_flush_pending_frames(sk);
 635         else if (!(msg->msg_flags & MSG_MORE))
 636                 err = l2tp_ip6_push_pending_frames(sk);
 637         release_sock(sk);
 638 done:
 639         dst_release(dst);
 640 out:
 641         fl6_sock_release(flowlabel);
 642         txopt_put(opt_to_free);
 643
 644         return err < 0 ? err : len;
 645
 646 do_confirm:
 647         dst_confirm(dst);
 648         if (!(msg->msg_flags & MSG_PROBE) || len)
 649                 goto back_from_confirm;
 650         err = 0;
 651         goto done;
 652 }
 653
 654 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 655                             int noblock, int flags, int *addr_len)
 656 {
 657         struct ipv6_pinfo *np = inet6_sk(sk);
 658         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 659         size_t copied = 0;
 660         int err = -EOPNOTSUPP;
 661         struct sk_buff *skb;
 662
 663         if (flags & MSG_OOB)
 664                 goto out;
 665
 666         if (addr_len)
 667                 *addr_len = sizeof(*lsa);
 668
 669         if (flags & MSG_ERRQUEUE)
 670                 return ipv6_recv_error(sk, msg, len, addr_len);
 671
 672         skb = skb_recv_datagram(sk, flags, noblock, &err);
 673         if (!skb)
 674                 goto out;
 675
 676         copied = skb->len;
 677         if (len < copied) {
 678                 msg->msg_flags |= MSG_TRUNC;
 679                 copied = len;
 680         }
 681
 682         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 683         if (err)
 684                 goto done;
 685
 686         sock_recv_timestamp(msg, sk, skb);
 687
 688         /* Copy the address. */
 689         if (lsa) {
 690                 lsa->l2tp_family = AF_INET6;
 691                 lsa->l2tp_unused = 0;
 692                 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 693                 lsa->l2tp_flowinfo = 0;
 694                 lsa->l2tp_scope_id = 0;
 695                 lsa->l2tp_conn_id = 0;
 696                 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 697                         lsa->l2tp_scope_id = inet6_iif(skb);
 698         }
 699
 700         if (np->rxopt.all)
 701                 ip6_datagram_recv_ctl(sk, msg, skb);
 702
 703         if (flags & MSG_TRUNC)
 704                 copied = skb->len;
 705 done:
 706         skb_free_datagram(sk, skb);
 707 out:
 708         return err ? err : copied;
 709 }
 710
 711 static struct proto l2tp_ip6_prot = {
 712         .name              = "L2TP/IPv6",
 713         .owner             = THIS_MODULE,
 714         .init              = l2tp_ip6_open,
 715         .close             = l2tp_ip6_close,
 716         .bind              = l2tp_ip6_bind,
 717         .connect           = l2tp_ip6_connect,
 718         .disconnect        = l2tp_ip6_disconnect,
 719         .ioctl             = l2tp_ioctl,
 720         .destroy           = l2tp_ip6_destroy_sock,
 721         .setsockopt        = ipv6_setsockopt,
 722         .getsockopt        = ipv6_getsockopt,
 723         .sendmsg           = l2tp_ip6_sendmsg,
 724         .recvmsg           = l2tp_ip6_recvmsg,
 725         .backlog_rcv       = l2tp_ip6_backlog_recv,
 726         .hash              = inet_hash,
 727         .unhash            = inet_unhash,
 728         .obj_size          = sizeof(struct l2tp_ip6_sock),
 729 #ifdef CONFIG_COMPAT
 730         .compat_setsockopt = compat_ipv6_setsockopt,
 731         .compat_getsockopt = compat_ipv6_getsockopt,
 732 #endif
 733 };
 734
 735 static const struct proto_ops l2tp_ip6_ops = {
 736         .family            = PF_INET6,
 737         .owner             = THIS_MODULE,
 738         .release           = inet6_release,
 739         .bind              = inet6_bind,
 740         .connect           = inet_dgram_connect,
 741         .socketpair        = sock_no_socketpair,
 742         .accept            = sock_no_accept,
 743         .getname           = l2tp_ip6_getname,
 744         .poll              = datagram_poll,
 745         .ioctl             = inet6_ioctl,
 746         .listen            = sock_no_listen,
 747         .shutdown          = inet_shutdown,
 748         .setsockopt        = sock_common_setsockopt,
 749         .getsockopt        = sock_common_getsockopt,
 750         .sendmsg           = inet_sendmsg,
 751         .recvmsg           = sock_common_recvmsg,
 752         .mmap              = sock_no_mmap,
 753         .sendpage          = sock_no_sendpage,
 754 #ifdef CONFIG_COMPAT
 755         .compat_setsockopt = compat_sock_common_setsockopt,
 756         .compat_getsockopt = compat_sock_common_getsockopt,
 757 #endif
 758 };
 759
 760 static struct inet_protosw l2tp_ip6_protosw = {
 761         .type           = SOCK_DGRAM,
 762         .protocol       = IPPROTO_L2TP,
 763         .prot           = &l2tp_ip6_prot,
 764         .ops            = &l2tp_ip6_ops,
 765 };
 766
 767 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 768         .handler        = l2tp_ip6_recv,
 769 };
 770
 771 static int __init l2tp_ip6_init(void)
 772 {
 773         int err;
 774
 775         pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 776
 777         err = proto_register(&l2tp_ip6_prot, 1);
 778         if (err != 0)
 779                 goto out;
 780
 781         err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 782         if (err)
 783                 goto out1;
 784
 785         inet6_register_protosw(&l2tp_ip6_protosw);
 786         return 0;
 787
 788 out1:
 789         proto_unregister(&l2tp_ip6_prot);
 790 out:
 791         return err;
 792 }
 793
 794 static void __exit l2tp_ip6_exit(void)
 795 {
 796         inet6_unregister_protosw(&l2tp_ip6_protosw);
 797         inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 798         proto_unregister(&l2tp_ip6_prot);
 799 }
 800
 801 module_init(l2tp_ip6_init);
 802 module_exit(l2tp_ip6_exit);
 803
 804 MODULE_LICENSE("GPL");
 805 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 806 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 807 MODULE_VERSION("1.0");
 808
 809 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 810  * enums
 811  */
 812 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
 813 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);