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 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         /* Point to L2TP header */
 140         optr = ptr = skb->data;
 141
 142         if (!pskb_may_pull(skb, 4))
 143                 goto discard;
 144
 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(&init_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                 pr_debug("%s: ip recv\n", tunnel->name);
 173                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 174         }
 175
 176         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
 177                          tunnel->recv_payload_hook);
 178         return 0;
 179
 180 pass_up:
 181         /* Get the tunnel_id from the L2TP header */
 182         if (!pskb_may_pull(skb, 12))
 183                 goto discard;
 184
 185         if ((skb->data[0] & 0xc0) != 0xc0)
 186                 goto discard;
 187
 188         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 189         tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
 190         if (tunnel != NULL)
 191                 sk = tunnel->sock;
 192         else {
 193                 struct ipv6hdr *iph = ipv6_hdr(skb);
 194
 195                 read_lock_bh(&l2tp_ip6_lock);
 196                 sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr,
 197                                             0, tunnel_id);
 198                 read_unlock_bh(&l2tp_ip6_lock);
 199         }
 200
 201         if (sk == NULL)
 202                 goto discard;
 203
 204         sock_hold(sk);
 205
 206         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 207                 goto discard_put;
 208
 209         nf_reset(skb);
 210
 211         return sk_receive_skb(sk, skb, 1);
 212
 213 discard_put:
 214         sock_put(sk);
 215
 216 discard:
 217         kfree_skb(skb);
 218         return 0;
 219 }
 220
 221 static int l2tp_ip6_open(struct sock *sk)
 222 {
 223         /* Prevent autobind. We don't have ports. */
 224         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 225
 226         write_lock_bh(&l2tp_ip6_lock);
 227         sk_add_node(sk, &l2tp_ip6_table);
 228         write_unlock_bh(&l2tp_ip6_lock);
 229
 230         return 0;
 231 }
 232
 233 static void l2tp_ip6_close(struct sock *sk, long timeout)
 234 {
 235         write_lock_bh(&l2tp_ip6_lock);
 236         hlist_del_init(&sk->sk_bind_node);
 237         sk_del_node_init(sk);
 238         write_unlock_bh(&l2tp_ip6_lock);
 239
 240         sk_common_release(sk);
 241 }
 242
 243 static void l2tp_ip6_destroy_sock(struct sock *sk)
 244 {
 245         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 246
 247         lock_sock(sk);
 248         ip6_flush_pending_frames(sk);
 249         release_sock(sk);
 250
 251         if (tunnel) {
 252                 l2tp_tunnel_closeall(tunnel);
 253                 sock_put(sk);
 254         }
 255
 256         inet6_destroy_sock(sk);
 257 }
 258
 259 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 260 {
 261         struct inet_sock *inet = inet_sk(sk);
 262         struct ipv6_pinfo *np = inet6_sk(sk);
 263         struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
 264         __be32 v4addr = 0;
 265         int addr_type;
 266         int err;
 267
 268         if (!sock_flag(sk, SOCK_ZAPPED))
 269                 return -EINVAL;
 270         if (addr->l2tp_family != AF_INET6)
 271                 return -EINVAL;
 272         if (addr_len < sizeof(*addr))
 273                 return -EINVAL;
 274
 275         addr_type = ipv6_addr_type(&addr->l2tp_addr);
 276
 277         /* l2tp_ip6 sockets are IPv6 only */
 278         if (addr_type == IPV6_ADDR_MAPPED)
 279                 return -EADDRNOTAVAIL;
 280
 281         /* L2TP is point-point, not multicast */
 282         if (addr_type & IPV6_ADDR_MULTICAST)
 283                 return -EADDRNOTAVAIL;
 284
 285         err = -EADDRINUSE;
 286         read_lock_bh(&l2tp_ip6_lock);
 287         if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr,
 288                                    sk->sk_bound_dev_if, addr->l2tp_conn_id))
 289                 goto out_in_use;
 290         read_unlock_bh(&l2tp_ip6_lock);
 291
 292         lock_sock(sk);
 293
 294         err = -EINVAL;
 295         if (sk->sk_state != TCP_CLOSE)
 296                 goto out_unlock;
 297
 298         /* Check if the address belongs to the host. */
 299         rcu_read_lock();
 300         if (addr_type != IPV6_ADDR_ANY) {
 301                 struct net_device *dev = NULL;
 302
 303                 if (addr_type & IPV6_ADDR_LINKLOCAL) {
 304                         if (addr_len >= sizeof(struct sockaddr_in6) &&
 305                             addr->l2tp_scope_id) {
 306                                 /* Override any existing binding, if another
 307                                  * one is supplied by user.
 308                                  */
 309                                 sk->sk_bound_dev_if = addr->l2tp_scope_id;
 310                         }
 311
 312                         /* Binding to link-local address requires an
 313                            interface */
 314                         if (!sk->sk_bound_dev_if)
 315                                 goto out_unlock_rcu;
 316
 317                         err = -ENODEV;
 318                         dev = dev_get_by_index_rcu(sock_net(sk),
 319                                                    sk->sk_bound_dev_if);
 320                         if (!dev)
 321                                 goto out_unlock_rcu;
 322                 }
 323
 324                 /* ipv4 addr of the socket is invalid.  Only the
 325                  * unspecified and mapped address have a v4 equivalent.
 326                  */
 327                 v4addr = LOOPBACK4_IPV6;
 328                 err = -EADDRNOTAVAIL;
 329                 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
 330                         goto out_unlock_rcu;
 331         }
 332         rcu_read_unlock();
 333
 334         inet->inet_rcv_saddr = inet->inet_saddr = v4addr;
 335         sk->sk_v6_rcv_saddr = addr->l2tp_addr;
 336         np->saddr = addr->l2tp_addr;
 337
 338         l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
 339
 340         write_lock_bh(&l2tp_ip6_lock);
 341         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 342         sk_del_node_init(sk);
 343         write_unlock_bh(&l2tp_ip6_lock);
 344
 345         sock_reset_flag(sk, SOCK_ZAPPED);
 346         release_sock(sk);
 347         return 0;
 348
 349 out_unlock_rcu:
 350         rcu_read_unlock();
 351 out_unlock:
 352         release_sock(sk);
 353         return err;
 354
 355 out_in_use:
 356         read_unlock_bh(&l2tp_ip6_lock);
 357         return err;
 358 }
 359
 360 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 361                             int addr_len)
 362 {
 363         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 364         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 365         struct in6_addr *daddr;
 366         int     addr_type;
 367         int rc;
 368
 369         if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
 370                 return -EINVAL;
 371
 372         if (addr_len < sizeof(*lsa))
 373                 return -EINVAL;
 374
 375         if (usin->sin6_family != AF_INET6)
 376                 return -EINVAL;
 377
 378         addr_type = ipv6_addr_type(&usin->sin6_addr);
 379         if (addr_type & IPV6_ADDR_MULTICAST)
 380                 return -EINVAL;
 381
 382         if (addr_type & IPV6_ADDR_MAPPED) {
 383                 daddr = &usin->sin6_addr;
 384                 if (ipv4_is_multicast(daddr->s6_addr32[3]))
 385                         return -EINVAL;
 386         }
 387
 388         rc = ip6_datagram_connect(sk, uaddr, addr_len);
 389
 390         lock_sock(sk);
 391
 392         l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 393
 394         write_lock_bh(&l2tp_ip6_lock);
 395         hlist_del_init(&sk->sk_bind_node);
 396         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 397         write_unlock_bh(&l2tp_ip6_lock);
 398
 399         release_sock(sk);
 400
 401         return rc;
 402 }
 403
 404 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 405 {
 406         if (sock_flag(sk, SOCK_ZAPPED))
 407                 return 0;
 408
 409         return udp_disconnect(sk, flags);
 410 }
 411
 412 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 413                             int *uaddr_len, int peer)
 414 {
 415         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 416         struct sock *sk = sock->sk;
 417         struct ipv6_pinfo *np = inet6_sk(sk);
 418         struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 419
 420         lsa->l2tp_family = AF_INET6;
 421         lsa->l2tp_flowinfo = 0;
 422         lsa->l2tp_scope_id = 0;
 423         lsa->l2tp_unused = 0;
 424         if (peer) {
 425                 if (!lsk->peer_conn_id)
 426                         return -ENOTCONN;
 427                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 428                 lsa->l2tp_addr = sk->sk_v6_daddr;
 429                 if (np->sndflow)
 430                         lsa->l2tp_flowinfo = np->flow_label;
 431         } else {
 432                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 433                         lsa->l2tp_addr = np->saddr;
 434                 else
 435                         lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
 436
 437                 lsa->l2tp_conn_id = lsk->conn_id;
 438         }
 439         if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 440                 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 441         *uaddr_len = sizeof(*lsa);
 442         return 0;
 443 }
 444
 445 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 446 {
 447         int rc;
 448
 449         /* Charge it to the socket, dropping if the queue is full. */
 450         rc = sock_queue_rcv_skb(sk, skb);
 451         if (rc < 0)
 452                 goto drop;
 453
 454         return 0;
 455
 456 drop:
 457         IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
 458         kfree_skb(skb);
 459         return -1;
 460 }
 461
 462 static int l2tp_ip6_push_pending_frames(struct sock *sk)
 463 {
 464         struct sk_buff *skb;
 465         __be32 *transhdr = NULL;
 466         int err = 0;
 467
 468         skb = skb_peek(&sk->sk_write_queue);
 469         if (skb == NULL)
 470                 goto out;
 471
 472         transhdr = (__be32 *)skb_transport_header(skb);
 473         *transhdr = 0;
 474
 475         err = ip6_push_pending_frames(sk);
 476
 477 out:
 478         return err;
 479 }
 480
 481 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 482  * control frames.
 483  */
 484 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 485 {
 486         struct ipv6_txoptions opt_space;
 487         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 488         struct in6_addr *daddr, *final_p, final;
 489         struct ipv6_pinfo *np = inet6_sk(sk);
 490         struct ipv6_txoptions *opt_to_free = NULL;
 491         struct ipv6_txoptions *opt = NULL;
 492         struct ip6_flowlabel *flowlabel = NULL;
 493         struct dst_entry *dst = NULL;
 494         struct flowi6 fl6;
 495         int addr_len = msg->msg_namelen;
 496         int hlimit = -1;
 497         int tclass = -1;
 498         int dontfrag = -1;
 499         int transhdrlen = 4; /* zero session-id */
 500         int ulen = len + transhdrlen;
 501         int err;
 502
 503         /* Rough check on arithmetic overflow,
 504            better check is made in ip6_append_data().
 505          */
 506         if (len > INT_MAX)
 507                 return -EMSGSIZE;
 508
 509         /* Mirror BSD error message compatibility */
 510         if (msg->msg_flags & MSG_OOB)
 511                 return -EOPNOTSUPP;
 512
 513         /*
 514          *      Get and verify the address.
 515          */
 516         memset(&fl6, 0, sizeof(fl6));
 517
 518         fl6.flowi6_mark = sk->sk_mark;
 519
 520         if (lsa) {
 521                 if (addr_len < SIN6_LEN_RFC2133)
 522                         return -EINVAL;
 523
 524                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 525                         return -EAFNOSUPPORT;
 526
 527                 daddr = &lsa->l2tp_addr;
 528                 if (np->sndflow) {
 529                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 530                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 531                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 532                                 if (flowlabel == NULL)
 533                                         return -EINVAL;
 534                         }
 535                 }
 536
 537                 /*
 538                  * Otherwise it will be difficult to maintain
 539                  * sk->sk_dst_cache.
 540                  */
 541                 if (sk->sk_state == TCP_ESTABLISHED &&
 542                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
 543                         daddr = &sk->sk_v6_daddr;
 544
 545                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 546                     lsa->l2tp_scope_id &&
 547                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 548                         fl6.flowi6_oif = lsa->l2tp_scope_id;
 549         } else {
 550                 if (sk->sk_state != TCP_ESTABLISHED)
 551                         return -EDESTADDRREQ;
 552
 553                 daddr = &sk->sk_v6_daddr;
 554                 fl6.flowlabel = np->flow_label;
 555         }
 556
 557         if (fl6.flowi6_oif == 0)
 558                 fl6.flowi6_oif = sk->sk_bound_dev_if;
 559
 560         if (msg->msg_controllen) {
 561                 opt = &opt_space;
 562                 memset(opt, 0, sizeof(struct ipv6_txoptions));
 563                 opt->tot_len = sizeof(struct ipv6_txoptions);
 564
 565                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
 566                                             &hlimit, &tclass, &dontfrag);
 567                 if (err < 0) {
 568                         fl6_sock_release(flowlabel);
 569                         return err;
 570                 }
 571                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 572                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 573                         if (flowlabel == NULL)
 574                                 return -EINVAL;
 575                 }
 576                 if (!(opt->opt_nflen|opt->opt_flen))
 577                         opt = NULL;
 578         }
 579
 580         if (!opt) {
 581                 opt = txopt_get(np);
 582                 opt_to_free = opt;
 583         }
 584         if (flowlabel)
 585                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
 586         opt = ipv6_fixup_options(&opt_space, opt);
 587
 588         fl6.flowi6_proto = sk->sk_protocol;
 589         if (!ipv6_addr_any(daddr))
 590                 fl6.daddr = *daddr;
 591         else
 592                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 593         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 594                 fl6.saddr = np->saddr;
 595
 596         final_p = fl6_update_dst(&fl6, opt, &final);
 597
 598         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 599                 fl6.flowi6_oif = np->mcast_oif;
 600         else if (!fl6.flowi6_oif)
 601                 fl6.flowi6_oif = np->ucast_oif;
 602
 603         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 604
 605         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 606         if (IS_ERR(dst)) {
 607                 err = PTR_ERR(dst);
 608                 goto out;
 609         }
 610
 611         if (hlimit < 0)
 612                 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 613
 614         if (tclass < 0)
 615                 tclass = np->tclass;
 616
 617         if (dontfrag < 0)
 618                 dontfrag = np->dontfrag;
 619
 620         if (msg->msg_flags & MSG_CONFIRM)
 621                 goto do_confirm;
 622
 623 back_from_confirm:
 624         lock_sock(sk);
 625         err = ip6_append_data(sk, ip_generic_getfrag, msg,
 626                               ulen, transhdrlen, hlimit, tclass, opt,
 627                               &fl6, (struct rt6_info *)dst,
 628                               msg->msg_flags, dontfrag);
 629         if (err)
 630                 ip6_flush_pending_frames(sk);
 631         else if (!(msg->msg_flags & MSG_MORE))
 632                 err = l2tp_ip6_push_pending_frames(sk);
 633         release_sock(sk);
 634 done:
 635         dst_release(dst);
 636 out:
 637         fl6_sock_release(flowlabel);
 638         txopt_put(opt_to_free);
 639
 640         return err < 0 ? err : len;
 641
 642 do_confirm:
 643         dst_confirm(dst);
 644         if (!(msg->msg_flags & MSG_PROBE) || len)
 645                 goto back_from_confirm;
 646         err = 0;
 647         goto done;
 648 }
 649
 650 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 651                             int noblock, int flags, int *addr_len)
 652 {
 653         struct ipv6_pinfo *np = inet6_sk(sk);
 654         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 655         size_t copied = 0;
 656         int err = -EOPNOTSUPP;
 657         struct sk_buff *skb;
 658
 659         if (flags & MSG_OOB)
 660                 goto out;
 661
 662         if (addr_len)
 663                 *addr_len = sizeof(*lsa);
 664
 665         if (flags & MSG_ERRQUEUE)
 666                 return ipv6_recv_error(sk, msg, len, addr_len);
 667
 668         skb = skb_recv_datagram(sk, flags, noblock, &err);
 669         if (!skb)
 670                 goto out;
 671
 672         copied = skb->len;
 673         if (len < copied) {
 674                 msg->msg_flags |= MSG_TRUNC;
 675                 copied = len;
 676         }
 677
 678         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 679         if (err)
 680                 goto done;
 681
 682         sock_recv_timestamp(msg, sk, skb);
 683
 684         /* Copy the address. */
 685         if (lsa) {
 686                 lsa->l2tp_family = AF_INET6;
 687                 lsa->l2tp_unused = 0;
 688                 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 689                 lsa->l2tp_flowinfo = 0;
 690                 lsa->l2tp_scope_id = 0;
 691                 lsa->l2tp_conn_id = 0;
 692                 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 693                         lsa->l2tp_scope_id = inet6_iif(skb);
 694         }
 695
 696         if (np->rxopt.all)
 697                 ip6_datagram_recv_ctl(sk, msg, skb);
 698
 699         if (flags & MSG_TRUNC)
 700                 copied = skb->len;
 701 done:
 702         skb_free_datagram(sk, skb);
 703 out:
 704         return err ? err : copied;
 705 }
 706
 707 static struct proto l2tp_ip6_prot = {
 708         .name              = "L2TP/IPv6",
 709         .owner             = THIS_MODULE,
 710         .init              = l2tp_ip6_open,
 711         .close             = l2tp_ip6_close,
 712         .bind              = l2tp_ip6_bind,
 713         .connect           = l2tp_ip6_connect,
 714         .disconnect        = l2tp_ip6_disconnect,
 715         .ioctl             = udp_ioctl,
 716         .destroy           = l2tp_ip6_destroy_sock,
 717         .setsockopt        = ipv6_setsockopt,
 718         .getsockopt        = ipv6_getsockopt,
 719         .sendmsg           = l2tp_ip6_sendmsg,
 720         .recvmsg           = l2tp_ip6_recvmsg,
 721         .backlog_rcv       = l2tp_ip6_backlog_recv,
 722         .hash              = inet6_hash,
 723         .unhash            = inet_unhash,
 724         .obj_size          = sizeof(struct l2tp_ip6_sock),
 725 #ifdef CONFIG_COMPAT
 726         .compat_setsockopt = compat_ipv6_setsockopt,
 727         .compat_getsockopt = compat_ipv6_getsockopt,
 728 #endif
 729 };
 730
 731 static const struct proto_ops l2tp_ip6_ops = {
 732         .family            = PF_INET6,
 733         .owner             = THIS_MODULE,
 734         .release           = inet6_release,
 735         .bind              = inet6_bind,
 736         .connect           = inet_dgram_connect,
 737         .socketpair        = sock_no_socketpair,
 738         .accept            = sock_no_accept,
 739         .getname           = l2tp_ip6_getname,
 740         .poll              = datagram_poll,
 741         .ioctl             = inet6_ioctl,
 742         .listen            = sock_no_listen,
 743         .shutdown          = inet_shutdown,
 744         .setsockopt        = sock_common_setsockopt,
 745         .getsockopt        = sock_common_getsockopt,
 746         .sendmsg           = inet_sendmsg,
 747         .recvmsg           = sock_common_recvmsg,
 748         .mmap              = sock_no_mmap,
 749         .sendpage          = sock_no_sendpage,
 750 #ifdef CONFIG_COMPAT
 751         .compat_setsockopt = compat_sock_common_setsockopt,
 752         .compat_getsockopt = compat_sock_common_getsockopt,
 753 #endif
 754 };
 755
 756 static struct inet_protosw l2tp_ip6_protosw = {
 757         .type           = SOCK_DGRAM,
 758         .protocol       = IPPROTO_L2TP,
 759         .prot           = &l2tp_ip6_prot,
 760         .ops            = &l2tp_ip6_ops,
 761 };
 762
 763 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 764         .handler        = l2tp_ip6_recv,
 765 };
 766
 767 static int __init l2tp_ip6_init(void)
 768 {
 769         int err;
 770
 771         pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 772
 773         err = proto_register(&l2tp_ip6_prot, 1);
 774         if (err != 0)
 775                 goto out;
 776
 777         err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 778         if (err)
 779                 goto out1;
 780
 781         inet6_register_protosw(&l2tp_ip6_protosw);
 782         return 0;
 783
 784 out1:
 785         proto_unregister(&l2tp_ip6_prot);
 786 out:
 787         return err;
 788 }
 789
 790 static void __exit l2tp_ip6_exit(void)
 791 {
 792         inet6_unregister_protosw(&l2tp_ip6_protosw);
 793         inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 794         proto_unregister(&l2tp_ip6_prot);
 795 }
 796
 797 module_init(l2tp_ip6_init);
 798 module_exit(l2tp_ip6_exit);
 799
 800 MODULE_LICENSE("GPL");
 801 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 802 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 803 MODULE_VERSION("1.0");
 804
 805 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 806  * enums
 807  */
 808 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
 809 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);