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/tcp_states.h>
  28 #include <net/protocol.h>
  29 #include <net/xfrm.h>
  30
  31 #include <net/transp_v6.h>
  32 #include <net/addrconf.h>
  33 #include <net/ip6_route.h>
  34
  35 #include "l2tp_core.h"
  36
  37 struct l2tp_ip6_sock {
  38         /* inet_sock has to be the first member of l2tp_ip6_sock */
  39         struct inet_sock        inet;
  40
  41         u32                     conn_id;
  42         u32                     peer_conn_id;
  43
  44         /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
  45            inet6_sk_generic */
  46         struct ipv6_pinfo       inet6;
  47 };
  48
  49 static DEFINE_RWLOCK(l2tp_ip6_lock);
  50 static struct hlist_head l2tp_ip6_table;
  51 static struct hlist_head l2tp_ip6_bind_table;
  52
  53 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
  54 {
  55         return (struct l2tp_ip6_sock *)sk;
  56 }
  57
  58 static struct sock *__l2tp_ip6_bind_lookup(struct net *net,
  59                                            struct in6_addr *laddr,
  60                                            int dif, u32 tunnel_id)
  61 {
  62         struct sock *sk;
  63
  64         sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
  65                 const struct in6_addr *addr = inet6_rcv_saddr(sk);
  66                 struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
  67
  68                 if (l2tp == NULL)
  69                         continue;
  70
  71                 if ((l2tp->conn_id == tunnel_id) &&
  72                     net_eq(sock_net(sk), net) &&
  73                     !(addr && ipv6_addr_equal(addr, laddr)) &&
  74                     !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
  75                         goto found;
  76         }
  77
  78         sk = NULL;
  79 found:
  80         return sk;
  81 }
  82
  83 static inline struct sock *l2tp_ip6_bind_lookup(struct net *net,
  84                                                 struct in6_addr *laddr,
  85                                                 int dif, u32 tunnel_id)
  86 {
  87         struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id);
  88         if (sk)
  89                 sock_hold(sk);
  90
  91         return sk;
  92 }
  93
  94 /* When processing receive frames, there are two cases to
  95  * consider. Data frames consist of a non-zero session-id and an
  96  * optional cookie. Control frames consist of a regular L2TP header
  97  * preceded by 32-bits of zeros.
  98  *
  99  * L2TPv3 Session Header Over IP
 100  *
 101  *  0                   1                   2                   3
 102  *  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
 103  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 104  * |                           Session ID                          |
 105  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 106  * |               Cookie (optional, maximum 64 bits)...
 107  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 108  *                                                                 |
 109  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 110  *
 111  * L2TPv3 Control Message Header Over IP
 112  *
 113  *  0                   1                   2                   3
 114  *  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
 115  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 116  * |                      (32 bits of zeros)                       |
 117  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 118  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 119  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 120  * |                     Control Connection ID                     |
 121  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 122  * |               Ns              |               Nr              |
 123  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 124  *
 125  * All control frames are passed to userspace.
 126  */
 127 static int l2tp_ip6_recv(struct sk_buff *skb)
 128 {
 129         struct net *net = dev_net(skb->dev);
 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         struct ipv6hdr *iph;
 137         int length;
 138
 139         if (!pskb_may_pull(skb, 4))
 140                 goto discard;
 141
 142         /* Point to L2TP header */
 143         optr = ptr = skb->data;
 144         session_id = ntohl(*((__be32 *) ptr));
 145         ptr += 4;
 146
 147         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 148          * the session_id. If it is 0, the packet is a L2TP control
 149          * frame and the session_id value can be discarded.
 150          */
 151         if (session_id == 0) {
 152                 __skb_pull(skb, 4);
 153                 goto pass_up;
 154         }
 155
 156         /* Ok, this is a data packet. Lookup the session. */
 157         session = l2tp_session_get(net, NULL, session_id, true);
 158         if (!session)
 159                 goto discard;
 160
 161         tunnel = session->tunnel;
 162         if (!tunnel)
 163                 goto discard_sess;
 164
 165         /* Trace packet contents, if enabled */
 166         if (tunnel->debug & L2TP_MSG_DATA) {
 167                 length = min(32u, skb->len);
 168                 if (!pskb_may_pull(skb, length))
 169                         goto discard_sess;
 170
 171                 /* Point to L2TP header */
 172                 optr = ptr = skb->data;
 173                 ptr += 4;
 174                 pr_debug("%s: ip recv\n", tunnel->name);
 175                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 176         }
 177
 178         if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
 179                 goto discard;
 180
 181         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
 182                          tunnel->recv_payload_hook);
 183         l2tp_session_dec_refcount(session);
 184
 185         return 0;
 186
 187 pass_up:
 188         /* Get the tunnel_id from the L2TP header */
 189         if (!pskb_may_pull(skb, 12))
 190                 goto discard;
 191
 192         if ((skb->data[0] & 0xc0) != 0xc0)
 193                 goto discard;
 194
 195         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 196         iph = ipv6_hdr(skb);
 197
 198         read_lock_bh(&l2tp_ip6_lock);
 199         sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, 0, tunnel_id);
 200         if (!sk) {
 201                 read_unlock_bh(&l2tp_ip6_lock);
 202                 goto discard;
 203         }
 204         sock_hold(sk);
 205         read_unlock_bh(&l2tp_ip6_lock);
 206
 207         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 208                 goto discard_put;
 209
 210         nf_reset(skb);
 211
 212         return sk_receive_skb(sk, skb, 1);
 213
 214 discard_sess:
 215         if (session->deref)
 216                 session->deref(session);
 217         l2tp_session_dec_refcount(session);
 218         goto discard;
 219
 220 discard_put:
 221         sock_put(sk);
 222
 223 discard:
 224         kfree_skb(skb);
 225         return 0;
 226 }
 227
 228 static void l2tp_ip6_hash(struct sock *sk)
 229 {
 230         if (sk_unhashed(sk)) {
 231                 write_lock_bh(&l2tp_ip6_lock);
 232                 sk_add_node(sk, &l2tp_ip6_table);
 233                 write_unlock_bh(&l2tp_ip6_lock);
 234         }
 235 }
 236
 237 static void l2tp_ip6_unhash(struct sock *sk)
 238 {
 239         if (sk_unhashed(sk))
 240                 return;
 241         write_lock_bh(&l2tp_ip6_lock);
 242         sk_del_node_init(sk);
 243         write_unlock_bh(&l2tp_ip6_lock);
 244 }
 245
 246 static int l2tp_ip6_open(struct sock *sk)
 247 {
 248         /* Prevent autobind. We don't have ports. */
 249         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 250
 251         l2tp_ip6_hash(sk);
 252         return 0;
 253 }
 254
 255 static void l2tp_ip6_close(struct sock *sk, long timeout)
 256 {
 257         write_lock_bh(&l2tp_ip6_lock);
 258         hlist_del_init(&sk->sk_bind_node);
 259         sk_del_node_init(sk);
 260         write_unlock_bh(&l2tp_ip6_lock);
 261
 262         sk_common_release(sk);
 263 }
 264
 265 static void l2tp_ip6_destroy_sock(struct sock *sk)
 266 {
 267         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 268
 269         lock_sock(sk);
 270         ip6_flush_pending_frames(sk);
 271         release_sock(sk);
 272
 273         if (tunnel) {
 274                 l2tp_tunnel_closeall(tunnel);
 275                 sock_put(sk);
 276         }
 277
 278         inet6_destroy_sock(sk);
 279 }
 280
 281 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 282 {
 283         struct inet_sock *inet = inet_sk(sk);
 284         struct ipv6_pinfo *np = inet6_sk(sk);
 285         struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
 286         struct net *net = sock_net(sk);
 287         __be32 v4addr = 0;
 288         int bound_dev_if;
 289         int addr_type;
 290         int err;
 291
 292         if (addr->l2tp_family != AF_INET6)
 293                 return -EINVAL;
 294         if (addr_len < sizeof(*addr))
 295                 return -EINVAL;
 296
 297         addr_type = ipv6_addr_type(&addr->l2tp_addr);
 298
 299         /* l2tp_ip6 sockets are IPv6 only */
 300         if (addr_type == IPV6_ADDR_MAPPED)
 301                 return -EADDRNOTAVAIL;
 302
 303         /* L2TP is point-point, not multicast */
 304         if (addr_type & IPV6_ADDR_MULTICAST)
 305                 return -EADDRNOTAVAIL;
 306
 307         lock_sock(sk);
 308
 309         err = -EINVAL;
 310         if (!sock_flag(sk, SOCK_ZAPPED))
 311                 goto out_unlock;
 312
 313         if (sk->sk_state != TCP_CLOSE)
 314                 goto out_unlock;
 315
 316         bound_dev_if = sk->sk_bound_dev_if;
 317
 318         /* Check if the address belongs to the host. */
 319         rcu_read_lock();
 320         if (addr_type != IPV6_ADDR_ANY) {
 321                 struct net_device *dev = NULL;
 322
 323                 if (addr_type & IPV6_ADDR_LINKLOCAL) {
 324                         if (addr->l2tp_scope_id)
 325                                 bound_dev_if = addr->l2tp_scope_id;
 326
 327                         /* Binding to link-local address requires an
 328                          * interface.
 329                          */
 330                         if (!bound_dev_if)
 331                                 goto out_unlock_rcu;
 332
 333                         err = -ENODEV;
 334                         dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
 335                         if (!dev)
 336                                 goto out_unlock_rcu;
 337                 }
 338
 339                 /* ipv4 addr of the socket is invalid.  Only the
 340                  * unspecified and mapped address have a v4 equivalent.
 341                  */
 342                 v4addr = LOOPBACK4_IPV6;
 343                 err = -EADDRNOTAVAIL;
 344                 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
 345                         goto out_unlock_rcu;
 346         }
 347         rcu_read_unlock();
 348
 349         write_lock_bh(&l2tp_ip6_lock);
 350         if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, bound_dev_if,
 351                                    addr->l2tp_conn_id)) {
 352                 write_unlock_bh(&l2tp_ip6_lock);
 353                 err = -EADDRINUSE;
 354                 goto out_unlock;
 355         }
 356
 357         inet->inet_saddr = v4addr;
 358         inet->inet_rcv_saddr = v4addr;
 359         sk->sk_bound_dev_if = bound_dev_if;
 360         sk->sk_v6_rcv_saddr = addr->l2tp_addr;
 361         np->saddr = addr->l2tp_addr;
 362
 363         l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
 364
 365         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 366         sk_del_node_init(sk);
 367         write_unlock_bh(&l2tp_ip6_lock);
 368
 369         sock_reset_flag(sk, SOCK_ZAPPED);
 370         release_sock(sk);
 371         return 0;
 372
 373 out_unlock_rcu:
 374         rcu_read_unlock();
 375 out_unlock:
 376         release_sock(sk);
 377
 378         return err;
 379 }
 380
 381 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 382                             int addr_len)
 383 {
 384         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 385         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 386         struct in6_addr *daddr;
 387         int     addr_type;
 388         int rc;
 389
 390         if (addr_len < sizeof(*lsa))
 391                 return -EINVAL;
 392
 393         if (usin->sin6_family != AF_INET6)
 394                 return -EINVAL;
 395
 396         addr_type = ipv6_addr_type(&usin->sin6_addr);
 397         if (addr_type & IPV6_ADDR_MULTICAST)
 398                 return -EINVAL;
 399
 400         if (addr_type & IPV6_ADDR_MAPPED) {
 401                 daddr = &usin->sin6_addr;
 402                 if (ipv4_is_multicast(daddr->s6_addr32[3]))
 403                         return -EINVAL;
 404         }
 405
 406         lock_sock(sk);
 407
 408          /* Must bind first - autobinding does not work */
 409         if (sock_flag(sk, SOCK_ZAPPED)) {
 410                 rc = -EINVAL;
 411                 goto out_sk;
 412         }
 413
 414         rc = __ip6_datagram_connect(sk, uaddr, addr_len);
 415         if (rc < 0)
 416                 goto out_sk;
 417
 418         l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 419
 420         write_lock_bh(&l2tp_ip6_lock);
 421         hlist_del_init(&sk->sk_bind_node);
 422         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 423         write_unlock_bh(&l2tp_ip6_lock);
 424
 425 out_sk:
 426         release_sock(sk);
 427
 428         return rc;
 429 }
 430
 431 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 432 {
 433         if (sock_flag(sk, SOCK_ZAPPED))
 434                 return 0;
 435
 436         return udp_disconnect(sk, flags);
 437 }
 438
 439 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 440                             int *uaddr_len, int peer)
 441 {
 442         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 443         struct sock *sk = sock->sk;
 444         struct ipv6_pinfo *np = inet6_sk(sk);
 445         struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 446
 447         lsa->l2tp_family = AF_INET6;
 448         lsa->l2tp_flowinfo = 0;
 449         lsa->l2tp_scope_id = 0;
 450         lsa->l2tp_unused = 0;
 451         if (peer) {
 452                 if (!lsk->peer_conn_id)
 453                         return -ENOTCONN;
 454                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 455                 lsa->l2tp_addr = sk->sk_v6_daddr;
 456                 if (np->sndflow)
 457                         lsa->l2tp_flowinfo = np->flow_label;
 458         } else {
 459                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 460                         lsa->l2tp_addr = np->saddr;
 461                 else
 462                         lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
 463
 464                 lsa->l2tp_conn_id = lsk->conn_id;
 465         }
 466         if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 467                 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 468         *uaddr_len = sizeof(*lsa);
 469         return 0;
 470 }
 471
 472 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 473 {
 474         int rc;
 475
 476         /* Charge it to the socket, dropping if the queue is full. */
 477         rc = sock_queue_rcv_skb(sk, skb);
 478         if (rc < 0)
 479                 goto drop;
 480
 481         return 0;
 482
 483 drop:
 484         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 485         kfree_skb(skb);
 486         return -1;
 487 }
 488
 489 static int l2tp_ip6_push_pending_frames(struct sock *sk)
 490 {
 491         struct sk_buff *skb;
 492         __be32 *transhdr = NULL;
 493         int err = 0;
 494
 495         skb = skb_peek(&sk->sk_write_queue);
 496         if (skb == NULL)
 497                 goto out;
 498
 499         transhdr = (__be32 *)skb_transport_header(skb);
 500         *transhdr = 0;
 501
 502         err = ip6_push_pending_frames(sk);
 503
 504 out:
 505         return err;
 506 }
 507
 508 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 509  * control frames.
 510  */
 511 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 512 {
 513         struct ipv6_txoptions opt_space;
 514         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 515         struct in6_addr *daddr, *final_p, final;
 516         struct ipv6_pinfo *np = inet6_sk(sk);
 517         struct ipv6_txoptions *opt_to_free = NULL;
 518         struct ipv6_txoptions *opt = NULL;
 519         struct ip6_flowlabel *flowlabel = NULL;
 520         struct dst_entry *dst = NULL;
 521         struct flowi6 fl6;
 522         int addr_len = msg->msg_namelen;
 523         int hlimit = -1;
 524         int tclass = -1;
 525         int dontfrag = -1;
 526         int transhdrlen = 4; /* zero session-id */
 527         int ulen = len + transhdrlen;
 528         int err;
 529
 530         /* Rough check on arithmetic overflow,
 531            better check is made in ip6_append_data().
 532          */
 533         if (len > INT_MAX)
 534                 return -EMSGSIZE;
 535
 536         /* Mirror BSD error message compatibility */
 537         if (msg->msg_flags & MSG_OOB)
 538                 return -EOPNOTSUPP;
 539
 540         /*
 541          *      Get and verify the address.
 542          */
 543         memset(&fl6, 0, sizeof(fl6));
 544
 545         fl6.flowi6_mark = sk->sk_mark;
 546
 547         if (lsa) {
 548                 if (addr_len < SIN6_LEN_RFC2133)
 549                         return -EINVAL;
 550
 551                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 552                         return -EAFNOSUPPORT;
 553
 554                 daddr = &lsa->l2tp_addr;
 555                 if (np->sndflow) {
 556                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 557                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 558                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 559                                 if (flowlabel == NULL)
 560                                         return -EINVAL;
 561                         }
 562                 }
 563
 564                 /*
 565                  * Otherwise it will be difficult to maintain
 566                  * sk->sk_dst_cache.
 567                  */
 568                 if (sk->sk_state == TCP_ESTABLISHED &&
 569                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
 570                         daddr = &sk->sk_v6_daddr;
 571
 572                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 573                     lsa->l2tp_scope_id &&
 574                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 575                         fl6.flowi6_oif = lsa->l2tp_scope_id;
 576         } else {
 577                 if (sk->sk_state != TCP_ESTABLISHED)
 578                         return -EDESTADDRREQ;
 579
 580                 daddr = &sk->sk_v6_daddr;
 581                 fl6.flowlabel = np->flow_label;
 582         }
 583
 584         if (fl6.flowi6_oif == 0)
 585                 fl6.flowi6_oif = sk->sk_bound_dev_if;
 586
 587         if (msg->msg_controllen) {
 588                 opt = &opt_space;
 589                 memset(opt, 0, sizeof(struct ipv6_txoptions));
 590                 opt->tot_len = sizeof(struct ipv6_txoptions);
 591
 592                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
 593                                             &hlimit, &tclass, &dontfrag);
 594                 if (err < 0) {
 595                         fl6_sock_release(flowlabel);
 596                         return err;
 597                 }
 598                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 599                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 600                         if (flowlabel == NULL)
 601                                 return -EINVAL;
 602                 }
 603                 if (!(opt->opt_nflen|opt->opt_flen))
 604                         opt = NULL;
 605         }
 606
 607         if (!opt) {
 608                 opt = txopt_get(np);
 609                 opt_to_free = opt;
 610         }
 611         if (flowlabel)
 612                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
 613         opt = ipv6_fixup_options(&opt_space, opt);
 614
 615         fl6.flowi6_proto = sk->sk_protocol;
 616         if (!ipv6_addr_any(daddr))
 617                 fl6.daddr = *daddr;
 618         else
 619                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 620         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 621                 fl6.saddr = np->saddr;
 622
 623         final_p = fl6_update_dst(&fl6, opt, &final);
 624
 625         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 626                 fl6.flowi6_oif = np->mcast_oif;
 627         else if (!fl6.flowi6_oif)
 628                 fl6.flowi6_oif = np->ucast_oif;
 629
 630         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 631
 632         dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
 633         if (IS_ERR(dst)) {
 634                 err = PTR_ERR(dst);
 635                 goto out;
 636         }
 637
 638         if (hlimit < 0)
 639                 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 640
 641         if (tclass < 0)
 642                 tclass = np->tclass;
 643
 644         if (dontfrag < 0)
 645                 dontfrag = np->dontfrag;
 646
 647         if (msg->msg_flags & MSG_CONFIRM)
 648                 goto do_confirm;
 649
 650 back_from_confirm:
 651         lock_sock(sk);
 652         err = ip6_append_data(sk, ip_generic_getfrag, msg,
 653                               ulen, transhdrlen, hlimit, tclass, opt,
 654                               &fl6, (struct rt6_info *)dst,
 655                               msg->msg_flags, dontfrag);
 656         if (err)
 657                 ip6_flush_pending_frames(sk);
 658         else if (!(msg->msg_flags & MSG_MORE))
 659                 err = l2tp_ip6_push_pending_frames(sk);
 660         release_sock(sk);
 661 done:
 662         dst_release(dst);
 663 out:
 664         fl6_sock_release(flowlabel);
 665         txopt_put(opt_to_free);
 666
 667         return err < 0 ? err : len;
 668
 669 do_confirm:
 670         dst_confirm(dst);
 671         if (!(msg->msg_flags & MSG_PROBE) || len)
 672                 goto back_from_confirm;
 673         err = 0;
 674         goto done;
 675 }
 676
 677 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 678                             int noblock, int flags, int *addr_len)
 679 {
 680         struct ipv6_pinfo *np = inet6_sk(sk);
 681         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 682         size_t copied = 0;
 683         int err = -EOPNOTSUPP;
 684         struct sk_buff *skb;
 685
 686         if (flags & MSG_OOB)
 687                 goto out;
 688
 689         if (flags & MSG_ERRQUEUE)
 690                 return ipv6_recv_error(sk, msg, len, addr_len);
 691
 692         skb = skb_recv_datagram(sk, flags, noblock, &err);
 693         if (!skb)
 694                 goto out;
 695
 696         copied = skb->len;
 697         if (len < copied) {
 698                 msg->msg_flags |= MSG_TRUNC;
 699                 copied = len;
 700         }
 701
 702         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 703         if (err)
 704                 goto done;
 705
 706         sock_recv_timestamp(msg, sk, skb);
 707
 708         /* Copy the address. */
 709         if (lsa) {
 710                 lsa->l2tp_family = AF_INET6;
 711                 lsa->l2tp_unused = 0;
 712                 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 713                 lsa->l2tp_flowinfo = 0;
 714                 lsa->l2tp_scope_id = 0;
 715                 lsa->l2tp_conn_id = 0;
 716                 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 717                         lsa->l2tp_scope_id = inet6_iif(skb);
 718                 *addr_len = sizeof(*lsa);
 719         }
 720
 721         if (np->rxopt.all)
 722                 ip6_datagram_recv_ctl(sk, msg, skb);
 723
 724         if (flags & MSG_TRUNC)
 725                 copied = skb->len;
 726 done:
 727         skb_free_datagram(sk, skb);
 728 out:
 729         return err ? err : copied;
 730 }
 731
 732 static struct proto l2tp_ip6_prot = {
 733         .name              = "L2TP/IPv6",
 734         .owner             = THIS_MODULE,
 735         .init              = l2tp_ip6_open,
 736         .close             = l2tp_ip6_close,
 737         .bind              = l2tp_ip6_bind,
 738         .connect           = l2tp_ip6_connect,
 739         .disconnect        = l2tp_ip6_disconnect,
 740         .ioctl             = l2tp_ioctl,
 741         .destroy           = l2tp_ip6_destroy_sock,
 742         .setsockopt        = ipv6_setsockopt,
 743         .getsockopt        = ipv6_getsockopt,
 744         .sendmsg           = l2tp_ip6_sendmsg,
 745         .recvmsg           = l2tp_ip6_recvmsg,
 746         .backlog_rcv       = l2tp_ip6_backlog_recv,
 747         .hash              = l2tp_ip6_hash,
 748         .unhash            = l2tp_ip6_unhash,
 749         .obj_size          = sizeof(struct l2tp_ip6_sock),
 750 #ifdef CONFIG_COMPAT
 751         .compat_setsockopt = compat_ipv6_setsockopt,
 752         .compat_getsockopt = compat_ipv6_getsockopt,
 753 #endif
 754 };
 755
 756 static const struct proto_ops l2tp_ip6_ops = {
 757         .family            = PF_INET6,
 758         .owner             = THIS_MODULE,
 759         .release           = inet6_release,
 760         .bind              = inet6_bind,
 761         .connect           = inet_dgram_connect,
 762         .socketpair        = sock_no_socketpair,
 763         .accept            = sock_no_accept,
 764         .getname           = l2tp_ip6_getname,
 765         .poll              = datagram_poll,
 766         .ioctl             = inet6_ioctl,
 767         .listen            = sock_no_listen,
 768         .shutdown          = inet_shutdown,
 769         .setsockopt        = sock_common_setsockopt,
 770         .getsockopt        = sock_common_getsockopt,
 771         .sendmsg           = inet_sendmsg,
 772         .recvmsg           = sock_common_recvmsg,
 773         .mmap              = sock_no_mmap,
 774         .sendpage          = sock_no_sendpage,
 775 #ifdef CONFIG_COMPAT
 776         .compat_setsockopt = compat_sock_common_setsockopt,
 777         .compat_getsockopt = compat_sock_common_getsockopt,
 778 #endif
 779 };
 780
 781 static struct inet_protosw l2tp_ip6_protosw = {
 782         .type           = SOCK_DGRAM,
 783         .protocol       = IPPROTO_L2TP,
 784         .prot           = &l2tp_ip6_prot,
 785         .ops            = &l2tp_ip6_ops,
 786 };
 787
 788 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 789         .handler        = l2tp_ip6_recv,
 790 };
 791
 792 static int __init l2tp_ip6_init(void)
 793 {
 794         int err;
 795
 796         pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 797
 798         err = proto_register(&l2tp_ip6_prot, 1);
 799         if (err != 0)
 800                 goto out;
 801
 802         err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 803         if (err)
 804                 goto out1;
 805
 806         inet6_register_protosw(&l2tp_ip6_protosw);
 807         return 0;
 808
 809 out1:
 810         proto_unregister(&l2tp_ip6_prot);
 811 out:
 812         return err;
 813 }
 814
 815 static void __exit l2tp_ip6_exit(void)
 816 {
 817         inet6_unregister_protosw(&l2tp_ip6_protosw);
 818         inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 819         proto_unregister(&l2tp_ip6_prot);
 820 }
 821
 822 module_init(l2tp_ip6_init);
 823 module_exit(l2tp_ip6_exit);
 824
 825 MODULE_LICENSE("GPL");
 826 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 827 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 828 MODULE_VERSION("1.0");
 829
 830 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 831  * enums
 832  */
 833 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
 834 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);