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(const struct net *net,
  61                                            const 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                 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
  71
  72                 if (!net_eq(sock_net(sk), net))
  73                         continue;
  74
  75                 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
  76                         continue;
  77
  78                 if (sk_laddr && !ipv6_addr_any(sk_laddr) &&
  79                     !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr))
  80                         continue;
  81
  82                 if (!ipv6_addr_any(sk_raddr) && raddr &&
  83                     !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr))
  84                         continue;
  85
  86                 if (l2tp->conn_id != tunnel_id)
  87                         continue;
  88
  89                 goto found;
  90         }
  91
  92         sk = NULL;
  93 found:
  94         return sk;
  95 }
  96
  97 /* When processing receive frames, there are two cases to
  98  * consider. Data frames consist of a non-zero session-id and an
  99  * optional cookie. Control frames consist of a regular L2TP header
 100  * preceded by 32-bits of zeros.
 101  *
 102  * L2TPv3 Session Header Over IP
 103  *
 104  *  0                   1                   2                   3
 105  *  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
 106  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 107  * |                           Session ID                          |
 108  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 109  * |               Cookie (optional, maximum 64 bits)...
 110  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 111  *                                                                 |
 112  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 113  *
 114  * L2TPv3 Control Message Header Over IP
 115  *
 116  *  0                   1                   2                   3
 117  *  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
 118  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 119  * |                      (32 bits of zeros)                       |
 120  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 121  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 122  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 123  * |                     Control Connection ID                     |
 124  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 125  * |               Ns              |               Nr              |
 126  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 127  *
 128  * All control frames are passed to userspace.
 129  */
 130 static int l2tp_ip6_recv(struct sk_buff *skb)
 131 {
 132         struct net *net = dev_net(skb->dev);
 133         struct sock *sk;
 134         u32 session_id;
 135         u32 tunnel_id;
 136         unsigned char *ptr, *optr;
 137         struct l2tp_session *session;
 138         struct l2tp_tunnel *tunnel = NULL;
 139         struct ipv6hdr *iph;
 140         int length;
 141
 142         if (!pskb_may_pull(skb, 4))
 143                 goto discard;
 144
 145         /* Point to L2TP header */
 146         optr = ptr = skb->data;
 147         session_id = ntohl(*((__be32 *) ptr));
 148         ptr += 4;
 149
 150         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 151          * the session_id. If it is 0, the packet is a L2TP control
 152          * frame and the session_id value can be discarded.
 153          */
 154         if (session_id == 0) {
 155                 __skb_pull(skb, 4);
 156                 goto pass_up;
 157         }
 158
 159         /* Ok, this is a data packet. Lookup the session. */
 160         session = l2tp_session_get(net, NULL, session_id, true);
 161         if (!session)
 162                 goto discard;
 163
 164         tunnel = session->tunnel;
 165         if (!tunnel)
 166                 goto discard_sess;
 167
 168         /* Trace packet contents, if enabled */
 169         if (tunnel->debug & L2TP_MSG_DATA) {
 170                 length = min(32u, skb->len);
 171                 if (!pskb_may_pull(skb, length))
 172                         goto discard_sess;
 173
 174                 /* Point to L2TP header */
 175                 optr = ptr = skb->data;
 176                 ptr += 4;
 177                 pr_debug("%s: ip recv\n", tunnel->name);
 178                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 179         }
 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, &iph->saddr,
 200                                     inet6_iif(skb), tunnel_id);
 201         if (!sk) {
 202                 read_unlock_bh(&l2tp_ip6_lock);
 203                 goto discard;
 204         }
 205         sock_hold(sk);
 206         read_unlock_bh(&l2tp_ip6_lock);
 207
 208         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 209                 goto discard_put;
 210
 211         nf_reset(skb);
 212
 213         return sk_receive_skb(sk, skb, 1);
 214
 215 discard_sess:
 216         if (session->deref)
 217                 session->deref(session);
 218         l2tp_session_dec_refcount(session);
 219         goto discard;
 220
 221 discard_put:
 222         sock_put(sk);
 223
 224 discard:
 225         kfree_skb(skb);
 226         return 0;
 227 }
 228
 229 static int l2tp_ip6_open(struct sock *sk)
 230 {
 231         /* Prevent autobind. We don't have ports. */
 232         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 233
 234         write_lock_bh(&l2tp_ip6_lock);
 235         sk_add_node(sk, &l2tp_ip6_table);
 236         write_unlock_bh(&l2tp_ip6_lock);
 237
 238         return 0;
 239 }
 240
 241 static void l2tp_ip6_close(struct sock *sk, long timeout)
 242 {
 243         write_lock_bh(&l2tp_ip6_lock);
 244         hlist_del_init(&sk->sk_bind_node);
 245         sk_del_node_init(sk);
 246         write_unlock_bh(&l2tp_ip6_lock);
 247
 248         sk_common_release(sk);
 249 }
 250
 251 static void l2tp_ip6_destroy_sock(struct sock *sk)
 252 {
 253         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 254
 255         lock_sock(sk);
 256         ip6_flush_pending_frames(sk);
 257         release_sock(sk);
 258
 259         if (tunnel) {
 260                 l2tp_tunnel_closeall(tunnel);
 261                 sock_put(sk);
 262         }
 263
 264         inet6_destroy_sock(sk);
 265 }
 266
 267 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 268 {
 269         struct inet_sock *inet = inet_sk(sk);
 270         struct ipv6_pinfo *np = inet6_sk(sk);
 271         struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
 272         struct net *net = sock_net(sk);
 273         __be32 v4addr = 0;
 274         int bound_dev_if;
 275         int addr_type;
 276         int err;
 277
 278         if (addr->l2tp_family != AF_INET6)
 279                 return -EINVAL;
 280         if (addr_len < sizeof(*addr))
 281                 return -EINVAL;
 282
 283         addr_type = ipv6_addr_type(&addr->l2tp_addr);
 284
 285         /* l2tp_ip6 sockets are IPv6 only */
 286         if (addr_type == IPV6_ADDR_MAPPED)
 287                 return -EADDRNOTAVAIL;
 288
 289         /* L2TP is point-point, not multicast */
 290         if (addr_type & IPV6_ADDR_MULTICAST)
 291                 return -EADDRNOTAVAIL;
 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         bound_dev_if = sk->sk_bound_dev_if;
 303
 304         /* Check if the address belongs to the host. */
 305         rcu_read_lock();
 306         if (addr_type != IPV6_ADDR_ANY) {
 307                 struct net_device *dev = NULL;
 308
 309                 if (addr_type & IPV6_ADDR_LINKLOCAL) {
 310                         if (addr->l2tp_scope_id)
 311                                 bound_dev_if = addr->l2tp_scope_id;
 312
 313                         /* Binding to link-local address requires an
 314                          * interface.
 315                          */
 316                         if (!bound_dev_if)
 317                                 goto out_unlock_rcu;
 318
 319                         err = -ENODEV;
 320                         dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
 321                         if (!dev)
 322                                 goto out_unlock_rcu;
 323                 }
 324
 325                 /* ipv4 addr of the socket is invalid.  Only the
 326                  * unspecified and mapped address have a v4 equivalent.
 327                  */
 328                 v4addr = LOOPBACK4_IPV6;
 329                 err = -EADDRNOTAVAIL;
 330                 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
 331                         goto out_unlock_rcu;
 332         }
 333         rcu_read_unlock();
 334
 335         write_lock_bh(&l2tp_ip6_lock);
 336         if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
 337                                    addr->l2tp_conn_id)) {
 338                 write_unlock_bh(&l2tp_ip6_lock);
 339                 err = -EADDRINUSE;
 340                 goto out_unlock;
 341         }
 342
 343         inet->inet_saddr = v4addr;
 344         inet->inet_rcv_saddr = v4addr;
 345         sk->sk_bound_dev_if = bound_dev_if;
 346         sk->sk_v6_rcv_saddr = addr->l2tp_addr;
 347         np->saddr = addr->l2tp_addr;
 348
 349         l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
 350
 351         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 352         sk_del_node_init(sk);
 353         write_unlock_bh(&l2tp_ip6_lock);
 354
 355         sock_reset_flag(sk, SOCK_ZAPPED);
 356         release_sock(sk);
 357         return 0;
 358
 359 out_unlock_rcu:
 360         rcu_read_unlock();
 361 out_unlock:
 362         release_sock(sk);
 363
 364         return err;
 365 }
 366
 367 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 368                             int addr_len)
 369 {
 370         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 371         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 372         struct in6_addr *daddr;
 373         int     addr_type;
 374         int rc;
 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         lock_sock(sk);
 393
 394          /* Must bind first - autobinding does not work */
 395         if (sock_flag(sk, SOCK_ZAPPED)) {
 396                 rc = -EINVAL;
 397                 goto out_sk;
 398         }
 399
 400         rc = __ip6_datagram_connect(sk, uaddr, addr_len);
 401         if (rc < 0)
 402                 goto out_sk;
 403
 404         l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 405
 406         write_lock_bh(&l2tp_ip6_lock);
 407         hlist_del_init(&sk->sk_bind_node);
 408         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 409         write_unlock_bh(&l2tp_ip6_lock);
 410
 411 out_sk:
 412         release_sock(sk);
 413
 414         return rc;
 415 }
 416
 417 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 418 {
 419         if (sock_flag(sk, SOCK_ZAPPED))
 420                 return 0;
 421
 422         return __udp_disconnect(sk, flags);
 423 }
 424
 425 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 426                             int *uaddr_len, int peer)
 427 {
 428         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 429         struct sock *sk = sock->sk;
 430         struct ipv6_pinfo *np = inet6_sk(sk);
 431         struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 432
 433         lsa->l2tp_family = AF_INET6;
 434         lsa->l2tp_flowinfo = 0;
 435         lsa->l2tp_scope_id = 0;
 436         lsa->l2tp_unused = 0;
 437         if (peer) {
 438                 if (!lsk->peer_conn_id)
 439                         return -ENOTCONN;
 440                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 441                 lsa->l2tp_addr = sk->sk_v6_daddr;
 442                 if (np->sndflow)
 443                         lsa->l2tp_flowinfo = np->flow_label;
 444         } else {
 445                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 446                         lsa->l2tp_addr = np->saddr;
 447                 else
 448                         lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
 449
 450                 lsa->l2tp_conn_id = lsk->conn_id;
 451         }
 452         if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 453                 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 454         *uaddr_len = sizeof(*lsa);
 455         return 0;
 456 }
 457
 458 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 459 {
 460         int rc;
 461
 462         /* Charge it to the socket, dropping if the queue is full. */
 463         rc = sock_queue_rcv_skb(sk, skb);
 464         if (rc < 0)
 465                 goto drop;
 466
 467         return 0;
 468
 469 drop:
 470         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 471         kfree_skb(skb);
 472         return -1;
 473 }
 474
 475 static int l2tp_ip6_push_pending_frames(struct sock *sk)
 476 {
 477         struct sk_buff *skb;
 478         __be32 *transhdr = NULL;
 479         int err = 0;
 480
 481         skb = skb_peek(&sk->sk_write_queue);
 482         if (skb == NULL)
 483                 goto out;
 484
 485         transhdr = (__be32 *)skb_transport_header(skb);
 486         *transhdr = 0;
 487
 488         err = ip6_push_pending_frames(sk);
 489
 490 out:
 491         return err;
 492 }
 493
 494 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 495  * control frames.
 496  */
 497 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 498 {
 499         struct ipv6_txoptions opt_space;
 500         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 501         struct in6_addr *daddr, *final_p, final;
 502         struct ipv6_pinfo *np = inet6_sk(sk);
 503         struct ipv6_txoptions *opt_to_free = NULL;
 504         struct ipv6_txoptions *opt = NULL;
 505         struct ip6_flowlabel *flowlabel = NULL;
 506         struct dst_entry *dst = NULL;
 507         struct flowi6 fl6;
 508         struct sockcm_cookie sockc_unused = {0};
 509         struct ipcm6_cookie ipc6;
 510         int addr_len = msg->msg_namelen;
 511         int transhdrlen = 4; /* zero session-id */
 512         int ulen = len + transhdrlen;
 513         int err;
 514
 515         /* Rough check on arithmetic overflow,
 516            better check is made in ip6_append_data().
 517          */
 518         if (len > INT_MAX)
 519                 return -EMSGSIZE;
 520
 521         /* Mirror BSD error message compatibility */
 522         if (msg->msg_flags & MSG_OOB)
 523                 return -EOPNOTSUPP;
 524
 525         /*
 526          *      Get and verify the address.
 527          */
 528         memset(&fl6, 0, sizeof(fl6));
 529
 530         fl6.flowi6_mark = sk->sk_mark;
 531         fl6.flowi6_uid = sk->sk_uid;
 532
 533         ipc6.hlimit = -1;
 534         ipc6.tclass = -1;
 535         ipc6.dontfrag = -1;
 536
 537         if (lsa) {
 538                 if (addr_len < SIN6_LEN_RFC2133)
 539                         return -EINVAL;
 540
 541                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 542                         return -EAFNOSUPPORT;
 543
 544                 daddr = &lsa->l2tp_addr;
 545                 if (np->sndflow) {
 546                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 547                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 548                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 549                                 if (flowlabel == NULL)
 550                                         return -EINVAL;
 551                         }
 552                 }
 553
 554                 /*
 555                  * Otherwise it will be difficult to maintain
 556                  * sk->sk_dst_cache.
 557                  */
 558                 if (sk->sk_state == TCP_ESTABLISHED &&
 559                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
 560                         daddr = &sk->sk_v6_daddr;
 561
 562                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 563                     lsa->l2tp_scope_id &&
 564                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 565                         fl6.flowi6_oif = lsa->l2tp_scope_id;
 566         } else {
 567                 if (sk->sk_state != TCP_ESTABLISHED)
 568                         return -EDESTADDRREQ;
 569
 570                 daddr = &sk->sk_v6_daddr;
 571                 fl6.flowlabel = np->flow_label;
 572         }
 573
 574         if (fl6.flowi6_oif == 0)
 575                 fl6.flowi6_oif = sk->sk_bound_dev_if;
 576
 577         if (msg->msg_controllen) {
 578                 opt = &opt_space;
 579                 memset(opt, 0, sizeof(struct ipv6_txoptions));
 580                 opt->tot_len = sizeof(struct ipv6_txoptions);
 581                 ipc6.opt = opt;
 582
 583                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6,
 584                                             &sockc_unused);
 585                 if (err < 0) {
 586                         fl6_sock_release(flowlabel);
 587                         return err;
 588                 }
 589                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 590                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 591                         if (flowlabel == NULL)
 592                                 return -EINVAL;
 593                 }
 594                 if (!(opt->opt_nflen|opt->opt_flen))
 595                         opt = NULL;
 596         }
 597
 598         if (!opt) {
 599                 opt = txopt_get(np);
 600                 opt_to_free = opt;
 601         }
 602         if (flowlabel)
 603                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
 604         opt = ipv6_fixup_options(&opt_space, opt);
 605         ipc6.opt = opt;
 606
 607         fl6.flowi6_proto = sk->sk_protocol;
 608         if (!ipv6_addr_any(daddr))
 609                 fl6.daddr = *daddr;
 610         else
 611                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 612         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 613                 fl6.saddr = np->saddr;
 614
 615         final_p = fl6_update_dst(&fl6, opt, &final);
 616
 617         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 618                 fl6.flowi6_oif = np->mcast_oif;
 619         else if (!fl6.flowi6_oif)
 620                 fl6.flowi6_oif = np->ucast_oif;
 621
 622         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 623
 624         if (ipc6.tclass < 0)
 625                 ipc6.tclass = np->tclass;
 626
 627         fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 628
 629         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 630         if (IS_ERR(dst)) {
 631                 err = PTR_ERR(dst);
 632                 goto out;
 633         }
 634
 635         if (ipc6.hlimit < 0)
 636                 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 637
 638         if (ipc6.dontfrag < 0)
 639                 ipc6.dontfrag = np->dontfrag;
 640
 641         if (msg->msg_flags & MSG_CONFIRM)
 642                 goto do_confirm;
 643
 644 back_from_confirm:
 645         lock_sock(sk);
 646         err = ip6_append_data(sk, ip_generic_getfrag, msg,
 647                               ulen, transhdrlen, &ipc6,
 648                               &fl6, (struct rt6_info *)dst,
 649                               msg->msg_flags, &sockc_unused);
 650         if (err)
 651                 ip6_flush_pending_frames(sk);
 652         else if (!(msg->msg_flags & MSG_MORE))
 653                 err = l2tp_ip6_push_pending_frames(sk);
 654         release_sock(sk);
 655 done:
 656         dst_release(dst);
 657 out:
 658         fl6_sock_release(flowlabel);
 659         txopt_put(opt_to_free);
 660
 661         return err < 0 ? err : len;
 662
 663 do_confirm:
 664         if (msg->msg_flags & MSG_PROBE)
 665                 dst_confirm_neigh(dst, &fl6.daddr);
 666         if (!(msg->msg_flags & MSG_PROBE) || len)
 667                 goto back_from_confirm;
 668         err = 0;
 669         goto done;
 670 }
 671
 672 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 673                             int noblock, int flags, int *addr_len)
 674 {
 675         struct ipv6_pinfo *np = inet6_sk(sk);
 676         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 677         size_t copied = 0;
 678         int err = -EOPNOTSUPP;
 679         struct sk_buff *skb;
 680
 681         if (flags & MSG_OOB)
 682                 goto out;
 683
 684         if (addr_len)
 685                 *addr_len = sizeof(*lsa);
 686
 687         if (flags & MSG_ERRQUEUE)
 688                 return ipv6_recv_error(sk, msg, len, addr_len);
 689
 690         skb = skb_recv_datagram(sk, flags, noblock, &err);
 691         if (!skb)
 692                 goto out;
 693
 694         copied = skb->len;
 695         if (len < copied) {
 696                 msg->msg_flags |= MSG_TRUNC;
 697                 copied = len;
 698         }
 699
 700         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 701         if (err)
 702                 goto done;
 703
 704         sock_recv_timestamp(msg, sk, skb);
 705
 706         /* Copy the address. */
 707         if (lsa) {
 708                 lsa->l2tp_family = AF_INET6;
 709                 lsa->l2tp_unused = 0;
 710                 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 711                 lsa->l2tp_flowinfo = 0;
 712                 lsa->l2tp_scope_id = 0;
 713                 lsa->l2tp_conn_id = 0;
 714                 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 715                         lsa->l2tp_scope_id = inet6_iif(skb);
 716         }
 717
 718         if (np->rxopt.all)
 719                 ip6_datagram_recv_ctl(sk, msg, skb);
 720
 721         if (flags & MSG_TRUNC)
 722                 copied = skb->len;
 723 done:
 724         skb_free_datagram(sk, skb);
 725 out:
 726         return err ? err : copied;
 727 }
 728
 729 static struct proto l2tp_ip6_prot = {
 730         .name              = "L2TP/IPv6",
 731         .owner             = THIS_MODULE,
 732         .init              = l2tp_ip6_open,
 733         .close             = l2tp_ip6_close,
 734         .bind              = l2tp_ip6_bind,
 735         .connect           = l2tp_ip6_connect,
 736         .disconnect        = l2tp_ip6_disconnect,
 737         .ioctl             = l2tp_ioctl,
 738         .destroy           = l2tp_ip6_destroy_sock,
 739         .setsockopt        = ipv6_setsockopt,
 740         .getsockopt        = ipv6_getsockopt,
 741         .sendmsg           = l2tp_ip6_sendmsg,
 742         .recvmsg           = l2tp_ip6_recvmsg,
 743         .backlog_rcv       = l2tp_ip6_backlog_recv,
 744         .hash              = inet6_hash,
 745         .unhash            = inet_unhash,
 746         .obj_size          = sizeof(struct l2tp_ip6_sock),
 747 #ifdef CONFIG_COMPAT
 748         .compat_setsockopt = compat_ipv6_setsockopt,
 749         .compat_getsockopt = compat_ipv6_getsockopt,
 750 #endif
 751 };
 752
 753 static const struct proto_ops l2tp_ip6_ops = {
 754         .family            = PF_INET6,
 755         .owner             = THIS_MODULE,
 756         .release           = inet6_release,
 757         .bind              = inet6_bind,
 758         .connect           = inet_dgram_connect,
 759         .socketpair        = sock_no_socketpair,
 760         .accept            = sock_no_accept,
 761         .getname           = l2tp_ip6_getname,
 762         .poll              = datagram_poll,
 763         .ioctl             = inet6_ioctl,
 764         .listen            = sock_no_listen,
 765         .shutdown          = inet_shutdown,
 766         .setsockopt        = sock_common_setsockopt,
 767         .getsockopt        = sock_common_getsockopt,
 768         .sendmsg           = inet_sendmsg,
 769         .recvmsg           = sock_common_recvmsg,
 770         .mmap              = sock_no_mmap,
 771         .sendpage          = sock_no_sendpage,
 772 #ifdef CONFIG_COMPAT
 773         .compat_setsockopt = compat_sock_common_setsockopt,
 774         .compat_getsockopt = compat_sock_common_getsockopt,
 775 #endif
 776 };
 777
 778 static struct inet_protosw l2tp_ip6_protosw = {
 779         .type           = SOCK_DGRAM,
 780         .protocol       = IPPROTO_L2TP,
 781         .prot           = &l2tp_ip6_prot,
 782         .ops            = &l2tp_ip6_ops,
 783 };
 784
 785 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 786         .handler        = l2tp_ip6_recv,
 787 };
 788
 789 static int __init l2tp_ip6_init(void)
 790 {
 791         int err;
 792
 793         pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 794
 795         err = proto_register(&l2tp_ip6_prot, 1);
 796         if (err != 0)
 797                 goto out;
 798
 799         err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 800         if (err)
 801                 goto out1;
 802
 803         inet6_register_protosw(&l2tp_ip6_protosw);
 804         return 0;
 805
 806 out1:
 807         proto_unregister(&l2tp_ip6_prot);
 808 out:
 809         return err;
 810 }
 811
 812 static void __exit l2tp_ip6_exit(void)
 813 {
 814         inet6_unregister_protosw(&l2tp_ip6_protosw);
 815         inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 816         proto_unregister(&l2tp_ip6_prot);
 817 }
 818
 819 module_init(l2tp_ip6_init);
 820 module_exit(l2tp_ip6_exit);
 821
 822 MODULE_LICENSE("GPL");
 823 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 824 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 825 MODULE_VERSION("1.0");
 826
 827 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 828  * enums
 829  */
 830 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
 831 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);