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                                            const struct in6_addr *raddr,
  63                                            int dif, u32 tunnel_id)
  64 {
  65         struct sock *sk;
  66
  67         sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
  68                 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
  69                 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr;
  70                 struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
  71
  72                 if (l2tp == NULL)
  73                         continue;
  74
  75                 if ((l2tp->conn_id == tunnel_id) &&
  76                     net_eq(sock_net(sk), net) &&
  77                     (!sk_laddr || ipv6_addr_any(sk_laddr) || ipv6_addr_equal(sk_laddr, laddr)) &&
  78                     (!raddr || ipv6_addr_any(sk_raddr) || ipv6_addr_equal(sk_raddr, raddr)) &&
  79                     (!sk->sk_bound_dev_if || !dif ||
  80                      sk->sk_bound_dev_if == dif))
  81                         goto found;
  82         }
  83
  84         sk = NULL;
  85 found:
  86         return sk;
  87 }
  88
  89 /* When processing receive frames, there are two cases to
  90  * consider. Data frames consist of a non-zero session-id and an
  91  * optional cookie. Control frames consist of a regular L2TP header
  92  * preceded by 32-bits of zeros.
  93  *
  94  * L2TPv3 Session Header Over IP
  95  *
  96  *  0                   1                   2                   3
  97  *  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
  98  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  99  * |                           Session ID                          |
 100  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 101  * |               Cookie (optional, maximum 64 bits)...
 102  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 103  *                                                                 |
 104  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 105  *
 106  * L2TPv3 Control Message Header Over IP
 107  *
 108  *  0                   1                   2                   3
 109  *  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
 110  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 111  * |                      (32 bits of zeros)                       |
 112  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 113  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 114  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 115  * |                     Control Connection ID                     |
 116  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 117  * |               Ns              |               Nr              |
 118  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 119  *
 120  * All control frames are passed to userspace.
 121  */
 122 static int l2tp_ip6_recv(struct sk_buff *skb)
 123 {
 124         struct net *net = dev_net(skb->dev);
 125         struct sock *sk;
 126         u32 session_id;
 127         u32 tunnel_id;
 128         unsigned char *ptr, *optr;
 129         struct l2tp_session *session;
 130         struct l2tp_tunnel *tunnel = NULL;
 131         int length;
 132
 133         if (!pskb_may_pull(skb, 4))
 134                 goto discard;
 135
 136         /* Point to L2TP header */
 137         optr = ptr = skb->data;
 138         session_id = ntohl(*((__be32 *) ptr));
 139         ptr += 4;
 140
 141         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 142          * the session_id. If it is 0, the packet is a L2TP control
 143          * frame and the session_id value can be discarded.
 144          */
 145         if (session_id == 0) {
 146                 __skb_pull(skb, 4);
 147                 goto pass_up;
 148         }
 149
 150         /* Ok, this is a data packet. Lookup the session. */
 151         session = l2tp_session_find(net, NULL, session_id);
 152         if (session == NULL)
 153                 goto discard;
 154
 155         tunnel = session->tunnel;
 156         if (tunnel == NULL)
 157                 goto discard;
 158
 159         /* Trace packet contents, if enabled */
 160         if (tunnel->debug & L2TP_MSG_DATA) {
 161                 length = min(32u, skb->len);
 162                 if (!pskb_may_pull(skb, length))
 163                         goto discard;
 164
 165                 /* Point to L2TP header */
 166                 optr = ptr = skb->data;
 167                 ptr += 4;
 168                 pr_debug("%s: ip recv\n", tunnel->name);
 169                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 170         }
 171
 172         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
 173                          tunnel->recv_payload_hook);
 174         return 0;
 175
 176 pass_up:
 177         /* Get the tunnel_id from the L2TP header */
 178         if (!pskb_may_pull(skb, 12))
 179                 goto discard;
 180
 181         if ((skb->data[0] & 0xc0) != 0xc0)
 182                 goto discard;
 183
 184         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 185         tunnel = l2tp_tunnel_find(net, tunnel_id);
 186         if (tunnel) {
 187                 sk = tunnel->sock;
 188                 sock_hold(sk);
 189         } else {
 190                 struct ipv6hdr *iph = ipv6_hdr(skb);
 191
 192                 read_lock_bh(&l2tp_ip6_lock);
 193                 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
 194                                             inet6_iif(skb), tunnel_id);
 195                 if (!sk) {
 196                         read_unlock_bh(&l2tp_ip6_lock);
 197                         goto discard;
 198                 }
 199
 200                 sock_hold(sk);
 201                 read_unlock_bh(&l2tp_ip6_lock);
 202         }
 203
 204         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 205                 goto discard_put;
 206
 207         nf_reset(skb);
 208
 209         return sk_receive_skb(sk, skb, 1);
 210
 211 discard_put:
 212         sock_put(sk);
 213
 214 discard:
 215         kfree_skb(skb);
 216         return 0;
 217 }
 218
 219 static int l2tp_ip6_open(struct sock *sk)
 220 {
 221         /* Prevent autobind. We don't have ports. */
 222         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 223
 224         write_lock_bh(&l2tp_ip6_lock);
 225         sk_add_node(sk, &l2tp_ip6_table);
 226         write_unlock_bh(&l2tp_ip6_lock);
 227
 228         return 0;
 229 }
 230
 231 static void l2tp_ip6_close(struct sock *sk, long timeout)
 232 {
 233         write_lock_bh(&l2tp_ip6_lock);
 234         hlist_del_init(&sk->sk_bind_node);
 235         sk_del_node_init(sk);
 236         write_unlock_bh(&l2tp_ip6_lock);
 237
 238         sk_common_release(sk);
 239 }
 240
 241 static void l2tp_ip6_destroy_sock(struct sock *sk)
 242 {
 243         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 244
 245         lock_sock(sk);
 246         ip6_flush_pending_frames(sk);
 247         release_sock(sk);
 248
 249         if (tunnel) {
 250                 l2tp_tunnel_closeall(tunnel);
 251                 sock_put(sk);
 252         }
 253
 254         inet6_destroy_sock(sk);
 255 }
 256
 257 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 258 {
 259         struct inet_sock *inet = inet_sk(sk);
 260         struct ipv6_pinfo *np = inet6_sk(sk);
 261         struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
 262         struct net *net = sock_net(sk);
 263         __be32 v4addr = 0;
 264         int bound_dev_if;
 265         int addr_type;
 266         int err;
 267
 268         if (addr->l2tp_family != AF_INET6)
 269                 return -EINVAL;
 270         if (addr_len < sizeof(*addr))
 271                 return -EINVAL;
 272
 273         addr_type = ipv6_addr_type(&addr->l2tp_addr);
 274
 275         /* l2tp_ip6 sockets are IPv6 only */
 276         if (addr_type == IPV6_ADDR_MAPPED)
 277                 return -EADDRNOTAVAIL;
 278
 279         /* L2TP is point-point, not multicast */
 280         if (addr_type & IPV6_ADDR_MULTICAST)
 281                 return -EADDRNOTAVAIL;
 282
 283         lock_sock(sk);
 284
 285         err = -EINVAL;
 286         if (!sock_flag(sk, SOCK_ZAPPED))
 287                 goto out_unlock;
 288
 289         if (sk->sk_state != TCP_CLOSE)
 290                 goto out_unlock;
 291
 292         bound_dev_if = sk->sk_bound_dev_if;
 293
 294         /* Check if the address belongs to the host. */
 295         rcu_read_lock();
 296         if (addr_type != IPV6_ADDR_ANY) {
 297                 struct net_device *dev = NULL;
 298
 299                 if (addr_type & IPV6_ADDR_LINKLOCAL) {
 300                         if (addr->l2tp_scope_id)
 301                                 bound_dev_if = addr->l2tp_scope_id;
 302
 303                         /* Binding to link-local address requires an
 304                          * interface.
 305                          */
 306                         if (!bound_dev_if)
 307                                 goto out_unlock_rcu;
 308
 309                         err = -ENODEV;
 310                         dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
 311                         if (!dev)
 312                                 goto out_unlock_rcu;
 313                 }
 314
 315                 /* ipv4 addr of the socket is invalid.  Only the
 316                  * unspecified and mapped address have a v4 equivalent.
 317                  */
 318                 v4addr = LOOPBACK4_IPV6;
 319                 err = -EADDRNOTAVAIL;
 320                 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
 321                         goto out_unlock_rcu;
 322         }
 323         rcu_read_unlock();
 324
 325         write_lock_bh(&l2tp_ip6_lock);
 326         if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
 327                                    addr->l2tp_conn_id)) {
 328                 write_unlock_bh(&l2tp_ip6_lock);
 329                 err = -EADDRINUSE;
 330                 goto out_unlock;
 331         }
 332
 333         inet->inet_saddr = v4addr;
 334         inet->inet_rcv_saddr = v4addr;
 335         sk->sk_bound_dev_if = bound_dev_if;
 336         sk->sk_v6_rcv_saddr = addr->l2tp_addr;
 337         np->saddr = addr->l2tp_addr;
 338
 339         l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
 340
 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
 354         return err;
 355 }
 356
 357 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 358                             int addr_len)
 359 {
 360         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 361         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 362         struct in6_addr *daddr;
 363         int     addr_type;
 364         int rc;
 365
 366         if (addr_len < sizeof(*lsa))
 367                 return -EINVAL;
 368
 369         if (usin->sin6_family != AF_INET6)
 370                 return -EINVAL;
 371
 372         addr_type = ipv6_addr_type(&usin->sin6_addr);
 373         if (addr_type & IPV6_ADDR_MULTICAST)
 374                 return -EINVAL;
 375
 376         if (addr_type & IPV6_ADDR_MAPPED) {
 377                 daddr = &usin->sin6_addr;
 378                 if (ipv4_is_multicast(daddr->s6_addr32[3]))
 379                         return -EINVAL;
 380         }
 381
 382         lock_sock(sk);
 383
 384          /* Must bind first - autobinding does not work */
 385         if (sock_flag(sk, SOCK_ZAPPED)) {
 386                 rc = -EINVAL;
 387                 goto out_sk;
 388         }
 389
 390         rc = __ip6_datagram_connect(sk, uaddr, addr_len);
 391         if (rc < 0)
 392                 goto out_sk;
 393
 394         l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 395
 396         write_lock_bh(&l2tp_ip6_lock);
 397         hlist_del_init(&sk->sk_bind_node);
 398         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 399         write_unlock_bh(&l2tp_ip6_lock);
 400
 401 out_sk:
 402         release_sock(sk);
 403
 404         return rc;
 405 }
 406
 407 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 408 {
 409         if (sock_flag(sk, SOCK_ZAPPED))
 410                 return 0;
 411
 412         return __udp_disconnect(sk, flags);
 413 }
 414
 415 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 416                             int *uaddr_len, int peer)
 417 {
 418         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 419         struct sock *sk = sock->sk;
 420         struct ipv6_pinfo *np = inet6_sk(sk);
 421         struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 422
 423         lsa->l2tp_family = AF_INET6;
 424         lsa->l2tp_flowinfo = 0;
 425         lsa->l2tp_scope_id = 0;
 426         lsa->l2tp_unused = 0;
 427         if (peer) {
 428                 if (!lsk->peer_conn_id)
 429                         return -ENOTCONN;
 430                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 431                 lsa->l2tp_addr = sk->sk_v6_daddr;
 432                 if (np->sndflow)
 433                         lsa->l2tp_flowinfo = np->flow_label;
 434         } else {
 435                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 436                         lsa->l2tp_addr = np->saddr;
 437                 else
 438                         lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
 439
 440                 lsa->l2tp_conn_id = lsk->conn_id;
 441         }
 442         if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 443                 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 444         *uaddr_len = sizeof(*lsa);
 445         return 0;
 446 }
 447
 448 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 449 {
 450         int rc;
 451
 452         /* Charge it to the socket, dropping if the queue is full. */
 453         rc = sock_queue_rcv_skb(sk, skb);
 454         if (rc < 0)
 455                 goto drop;
 456
 457         return 0;
 458
 459 drop:
 460         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 461         kfree_skb(skb);
 462         return -1;
 463 }
 464
 465 static int l2tp_ip6_push_pending_frames(struct sock *sk)
 466 {
 467         struct sk_buff *skb;
 468         __be32 *transhdr = NULL;
 469         int err = 0;
 470
 471         skb = skb_peek(&sk->sk_write_queue);
 472         if (skb == NULL)
 473                 goto out;
 474
 475         transhdr = (__be32 *)skb_transport_header(skb);
 476         *transhdr = 0;
 477
 478         err = ip6_push_pending_frames(sk);
 479
 480 out:
 481         return err;
 482 }
 483
 484 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 485  * control frames.
 486  */
 487 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 488 {
 489         struct ipv6_txoptions opt_space;
 490         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 491         struct in6_addr *daddr, *final_p, final;
 492         struct ipv6_pinfo *np = inet6_sk(sk);
 493         struct ipv6_txoptions *opt_to_free = NULL;
 494         struct ipv6_txoptions *opt = NULL;
 495         struct ip6_flowlabel *flowlabel = NULL;
 496         struct dst_entry *dst = NULL;
 497         struct flowi6 fl6;
 498         struct sockcm_cookie sockc_unused = {0};
 499         struct ipcm6_cookie ipc6;
 500         int addr_len = msg->msg_namelen;
 501         int transhdrlen = 4; /* zero session-id */
 502         int ulen = len + transhdrlen;
 503         int err;
 504
 505         /* Rough check on arithmetic overflow,
 506            better check is made in ip6_append_data().
 507          */
 508         if (len > INT_MAX)
 509                 return -EMSGSIZE;
 510
 511         /* Mirror BSD error message compatibility */
 512         if (msg->msg_flags & MSG_OOB)
 513                 return -EOPNOTSUPP;
 514
 515         /*
 516          *      Get and verify the address.
 517          */
 518         memset(&fl6, 0, sizeof(fl6));
 519
 520         fl6.flowi6_mark = sk->sk_mark;
 521         fl6.flowi6_uid = sk->sk_uid;
 522
 523         ipc6.hlimit = -1;
 524         ipc6.tclass = -1;
 525         ipc6.dontfrag = -1;
 526
 527         if (lsa) {
 528                 if (addr_len < SIN6_LEN_RFC2133)
 529                         return -EINVAL;
 530
 531                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 532                         return -EAFNOSUPPORT;
 533
 534                 daddr = &lsa->l2tp_addr;
 535                 if (np->sndflow) {
 536                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 537                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 538                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 539                                 if (flowlabel == NULL)
 540                                         return -EINVAL;
 541                         }
 542                 }
 543
 544                 /*
 545                  * Otherwise it will be difficult to maintain
 546                  * sk->sk_dst_cache.
 547                  */
 548                 if (sk->sk_state == TCP_ESTABLISHED &&
 549                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
 550                         daddr = &sk->sk_v6_daddr;
 551
 552                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 553                     lsa->l2tp_scope_id &&
 554                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 555                         fl6.flowi6_oif = lsa->l2tp_scope_id;
 556         } else {
 557                 if (sk->sk_state != TCP_ESTABLISHED)
 558                         return -EDESTADDRREQ;
 559
 560                 daddr = &sk->sk_v6_daddr;
 561                 fl6.flowlabel = np->flow_label;
 562         }
 563
 564         if (fl6.flowi6_oif == 0)
 565                 fl6.flowi6_oif = sk->sk_bound_dev_if;
 566
 567         if (msg->msg_controllen) {
 568                 opt = &opt_space;
 569                 memset(opt, 0, sizeof(struct ipv6_txoptions));
 570                 opt->tot_len = sizeof(struct ipv6_txoptions);
 571                 ipc6.opt = opt;
 572
 573                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6,
 574                                             &sockc_unused);
 575                 if (err < 0) {
 576                         fl6_sock_release(flowlabel);
 577                         return err;
 578                 }
 579                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 580                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 581                         if (flowlabel == NULL)
 582                                 return -EINVAL;
 583                 }
 584                 if (!(opt->opt_nflen|opt->opt_flen))
 585                         opt = NULL;
 586         }
 587
 588         if (!opt) {
 589                 opt = txopt_get(np);
 590                 opt_to_free = opt;
 591         }
 592         if (flowlabel)
 593                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
 594         opt = ipv6_fixup_options(&opt_space, opt);
 595         ipc6.opt = opt;
 596
 597         fl6.flowi6_proto = sk->sk_protocol;
 598         if (!ipv6_addr_any(daddr))
 599                 fl6.daddr = *daddr;
 600         else
 601                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 602         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 603                 fl6.saddr = np->saddr;
 604
 605         final_p = fl6_update_dst(&fl6, opt, &final);
 606
 607         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 608                 fl6.flowi6_oif = np->mcast_oif;
 609         else if (!fl6.flowi6_oif)
 610                 fl6.flowi6_oif = np->ucast_oif;
 611
 612         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 613
 614         if (ipc6.tclass < 0)
 615                 ipc6.tclass = np->tclass;
 616
 617         fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 618
 619         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 620         if (IS_ERR(dst)) {
 621                 err = PTR_ERR(dst);
 622                 goto out;
 623         }
 624
 625         if (ipc6.hlimit < 0)
 626                 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 627
 628         if (ipc6.dontfrag < 0)
 629                 ipc6.dontfrag = np->dontfrag;
 630
 631         if (msg->msg_flags & MSG_CONFIRM)
 632                 goto do_confirm;
 633
 634 back_from_confirm:
 635         lock_sock(sk);
 636         err = ip6_append_data(sk, ip_generic_getfrag, msg,
 637                               ulen, transhdrlen, &ipc6,
 638                               &fl6, (struct rt6_info *)dst,
 639                               msg->msg_flags, &sockc_unused);
 640         if (err)
 641                 ip6_flush_pending_frames(sk);
 642         else if (!(msg->msg_flags & MSG_MORE))
 643                 err = l2tp_ip6_push_pending_frames(sk);
 644         release_sock(sk);
 645 done:
 646         dst_release(dst);
 647 out:
 648         fl6_sock_release(flowlabel);
 649         txopt_put(opt_to_free);
 650
 651         return err < 0 ? err : len;
 652
 653 do_confirm:
 654         if (msg->msg_flags & MSG_PROBE)
 655                 dst_confirm_neigh(dst, &fl6.daddr);
 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             = l2tp_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);