net/l2tp/l2tp_ip6.c

   1 /*
   2  * L2TPv3 IP encapsulation support for IPv6
   3  *
   4  * Copyright (c) 2012 Katalix Systems Ltd
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/icmp.h>
  15 #include <linux/module.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/random.h>
  18 #include <linux/socket.h>
  19 #include <linux/l2tp.h>
  20 #include <linux/in.h>
  21 #include <linux/in6.h>
  22 #include <net/sock.h>
  23 #include <net/ip.h>
  24 #include <net/icmp.h>
  25 #include <net/udp.h>
  26 #include <net/inet_common.h>
  27 #include <net/inet_hashtables.h>
  28 #include <net/tcp_states.h>
  29 #include <net/protocol.h>
  30 #include <net/xfrm.h>
  31
  32 #include <net/transp_v6.h>
  33 #include <net/addrconf.h>
  34 #include <net/ip6_route.h>
  35
  36 #include "l2tp_core.h"
  37
  38 struct l2tp_ip6_sock {
  39         /* inet_sock has to be the first member of l2tp_ip6_sock */
  40         struct inet_sock        inet;
  41
  42         u32                     conn_id;
  43         u32                     peer_conn_id;
  44
  45         /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
  46            inet6_sk_generic */
  47         struct ipv6_pinfo       inet6;
  48 };
  49
  50 static DEFINE_RWLOCK(l2tp_ip6_lock);
  51 static struct hlist_head l2tp_ip6_table;
  52 static struct hlist_head l2tp_ip6_bind_table;
  53
  54 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
  55 {
  56         return (struct l2tp_ip6_sock *)sk;
  57 }
  58
  59 static struct sock *__l2tp_ip6_bind_lookup(struct net *net,
  60                                            struct in6_addr *laddr,
  61                                            int dif, u32 tunnel_id)
  62 {
  63         struct sock *sk;
  64
  65         sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
  66                 struct in6_addr *addr = inet6_rcv_saddr(sk);
  67                 struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
  68
  69                 if (l2tp == NULL)
  70                         continue;
  71
  72                 if ((l2tp->conn_id == tunnel_id) &&
  73                     net_eq(sock_net(sk), net) &&
  74                     !(addr && ipv6_addr_equal(addr, laddr)) &&
  75                     !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
  76                         goto found;
  77         }
  78
  79         sk = NULL;
  80 found:
  81         return sk;
  82 }
  83
  84 static inline struct sock *l2tp_ip6_bind_lookup(struct net *net,
  85                                                 struct in6_addr *laddr,
  86                                                 int dif, u32 tunnel_id)
  87 {
  88         struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id);
  89         if (sk)
  90                 sock_hold(sk);
  91
  92         return sk;
  93 }
  94
  95 /* When processing receive frames, there are two cases to
  96  * consider. Data frames consist of a non-zero session-id and an
  97  * optional cookie. Control frames consist of a regular L2TP header
  98  * preceded by 32-bits of zeros.
  99  *
 100  * L2TPv3 Session Header Over IP
 101  *
 102  *  0                   1                   2                   3
 103  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 104  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 105  * |                           Session ID                          |
 106  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 107  * |               Cookie (optional, maximum 64 bits)...
 108  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 109  *                                                                 |
 110  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 111  *
 112  * L2TPv3 Control Message Header Over IP
 113  *
 114  *  0                   1                   2                   3
 115  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 116  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 117  * |                      (32 bits of zeros)                       |
 118  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 119  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 120  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 121  * |                     Control Connection ID                     |
 122  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 123  * |               Ns              |               Nr              |
 124  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 125  *
 126  * All control frames are passed to userspace.
 127  */
 128 static int l2tp_ip6_recv(struct sk_buff *skb)
 129 {
 130         struct sock *sk;
 131         u32 session_id;
 132         u32 tunnel_id;
 133         unsigned char *ptr, *optr;
 134         struct l2tp_session *session;
 135         struct l2tp_tunnel *tunnel = NULL;
 136         int length;
 137
 138         if (!pskb_may_pull(skb, 4))
 139                 goto discard;
 140
 141         /* Point to L2TP header */
 142         optr = ptr = skb->data;
 143         session_id = ntohl(*((__be32 *) ptr));
 144         ptr += 4;
 145
 146         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 147          * the session_id. If it is 0, the packet is a L2TP control
 148          * frame and the session_id value can be discarded.
 149          */
 150         if (session_id == 0) {
 151                 __skb_pull(skb, 4);
 152                 goto pass_up;
 153         }
 154
 155         /* Ok, this is a data packet. Lookup the session. */
 156         session = l2tp_session_find(&init_net, NULL, session_id);
 157         if (session == NULL)
 158                 goto discard;
 159
 160         tunnel = session->tunnel;
 161         if (tunnel == NULL)
 162                 goto discard;
 163
 164         /* Trace packet contents, if enabled */
 165         if (tunnel->debug & L2TP_MSG_DATA) {
 166                 length = min(32u, skb->len);
 167                 if (!pskb_may_pull(skb, length))
 168                         goto discard;
 169
 170                 /* Point to L2TP header */
 171                 optr = ptr = skb->data;
 172                 ptr += 4;
 173                 pr_debug("%s: ip recv\n", tunnel->name);
 174                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 175         }
 176
 177         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
 178                          tunnel->recv_payload_hook);
 179         return 0;
 180
 181 pass_up:
 182         /* Get the tunnel_id from the L2TP header */
 183         if (!pskb_may_pull(skb, 12))
 184                 goto discard;
 185
 186         if ((skb->data[0] & 0xc0) != 0xc0)
 187                 goto discard;
 188
 189         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 190         tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
 191         if (tunnel != NULL)
 192                 sk = tunnel->sock;
 193         else {
 194                 struct ipv6hdr *iph = ipv6_hdr(skb);
 195
 196                 read_lock_bh(&l2tp_ip6_lock);
 197                 sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr,
 198                                             0, tunnel_id);
 199                 read_unlock_bh(&l2tp_ip6_lock);
 200         }
 201
 202         if (sk == NULL)
 203                 goto discard;
 204
 205         sock_hold(sk);
 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_put:
 215         sock_put(sk);
 216
 217 discard:
 218         kfree_skb(skb);
 219         return 0;
 220 }
 221
 222 static int l2tp_ip6_open(struct sock *sk)
 223 {
 224         /* Prevent autobind. We don't have ports. */
 225         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 226
 227         write_lock_bh(&l2tp_ip6_lock);
 228         sk_add_node(sk, &l2tp_ip6_table);
 229         write_unlock_bh(&l2tp_ip6_lock);
 230
 231         return 0;
 232 }
 233
 234 static void l2tp_ip6_close(struct sock *sk, long timeout)
 235 {
 236         write_lock_bh(&l2tp_ip6_lock);
 237         hlist_del_init(&sk->sk_bind_node);
 238         sk_del_node_init(sk);
 239         write_unlock_bh(&l2tp_ip6_lock);
 240
 241         sk_common_release(sk);
 242 }
 243
 244 static void l2tp_ip6_destroy_sock(struct sock *sk)
 245 {
 246         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 247
 248         lock_sock(sk);
 249         ip6_flush_pending_frames(sk);
 250         release_sock(sk);
 251
 252         if (tunnel) {
 253                 l2tp_tunnel_closeall(tunnel);
 254                 sock_put(sk);
 255         }
 256
 257         inet6_destroy_sock(sk);
 258 }
 259
 260 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 261 {
 262         struct inet_sock *inet = inet_sk(sk);
 263         struct ipv6_pinfo *np = inet6_sk(sk);
 264         struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
 265         __be32 v4addr = 0;
 266         int addr_type;
 267         int err;
 268
 269         if (!sock_flag(sk, SOCK_ZAPPED))
 270                 return -EINVAL;
 271         if (addr->l2tp_family != AF_INET6)
 272                 return -EINVAL;
 273         if (addr_len < sizeof(*addr))
 274                 return -EINVAL;
 275
 276         addr_type = ipv6_addr_type(&addr->l2tp_addr);
 277
 278         /* l2tp_ip6 sockets are IPv6 only */
 279         if (addr_type == IPV6_ADDR_MAPPED)
 280                 return -EADDRNOTAVAIL;
 281
 282         /* L2TP is point-point, not multicast */
 283         if (addr_type & IPV6_ADDR_MULTICAST)
 284                 return -EADDRNOTAVAIL;
 285
 286         err = -EADDRINUSE;
 287         read_lock_bh(&l2tp_ip6_lock);
 288         if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr,
 289                                    sk->sk_bound_dev_if, addr->l2tp_conn_id))
 290                 goto out_in_use;
 291         read_unlock_bh(&l2tp_ip6_lock);
 292
 293         lock_sock(sk);
 294
 295         err = -EINVAL;
 296         if (sk->sk_state != TCP_CLOSE)
 297                 goto out_unlock;
 298
 299         /* Check if the address belongs to the host. */
 300         rcu_read_lock();
 301         if (addr_type != IPV6_ADDR_ANY) {
 302                 struct net_device *dev = NULL;
 303
 304                 if (addr_type & IPV6_ADDR_LINKLOCAL) {
 305                         if (addr_len >= sizeof(struct sockaddr_in6) &&
 306                             addr->l2tp_scope_id) {
 307                                 /* Override any existing binding, if another
 308                                  * one is supplied by user.
 309                                  */
 310                                 sk->sk_bound_dev_if = addr->l2tp_scope_id;
 311                         }
 312
 313                         /* Binding to link-local address requires an
 314                            interface */
 315                         if (!sk->sk_bound_dev_if)
 316                                 goto out_unlock_rcu;
 317
 318                         err = -ENODEV;
 319                         dev = dev_get_by_index_rcu(sock_net(sk),
 320                                                    sk->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         inet->inet_rcv_saddr = inet->inet_saddr = v4addr;
 336         np->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         write_lock_bh(&l2tp_ip6_lock);
 342         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 343         sk_del_node_init(sk);
 344         write_unlock_bh(&l2tp_ip6_lock);
 345
 346         sock_reset_flag(sk, SOCK_ZAPPED);
 347         release_sock(sk);
 348         return 0;
 349
 350 out_unlock_rcu:
 351         rcu_read_unlock();
 352 out_unlock:
 353         release_sock(sk);
 354         return err;
 355
 356 out_in_use:
 357         read_unlock_bh(&l2tp_ip6_lock);
 358         return err;
 359 }
 360
 361 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 362                             int addr_len)
 363 {
 364         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 365         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 366         struct in6_addr *daddr;
 367         int     addr_type;
 368         int rc;
 369
 370         if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
 371                 return -EINVAL;
 372
 373         if (addr_len < sizeof(*lsa))
 374                 return -EINVAL;
 375
 376         addr_type = ipv6_addr_type(&usin->sin6_addr);
 377         if (addr_type & IPV6_ADDR_MULTICAST)
 378                 return -EINVAL;
 379
 380         if (addr_type & IPV6_ADDR_MAPPED) {
 381                 daddr = &usin->sin6_addr;
 382                 if (ipv4_is_multicast(daddr->s6_addr32[3]))
 383                         return -EINVAL;
 384         }
 385
 386         rc = ip6_datagram_connect(sk, uaddr, addr_len);
 387
 388         lock_sock(sk);
 389
 390         l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 391
 392         write_lock_bh(&l2tp_ip6_lock);
 393         hlist_del_init(&sk->sk_bind_node);
 394         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 395         write_unlock_bh(&l2tp_ip6_lock);
 396
 397         release_sock(sk);
 398
 399         return rc;
 400 }
 401
 402 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 403 {
 404         if (sock_flag(sk, SOCK_ZAPPED))
 405                 return 0;
 406
 407         return udp_disconnect(sk, flags);
 408 }
 409
 410 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 411                             int *uaddr_len, int peer)
 412 {
 413         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 414         struct sock *sk = sock->sk;
 415         struct ipv6_pinfo *np = inet6_sk(sk);
 416         struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 417
 418         lsa->l2tp_family = AF_INET6;
 419         lsa->l2tp_flowinfo = 0;
 420         lsa->l2tp_scope_id = 0;
 421         lsa->l2tp_unused = 0;
 422         if (peer) {
 423                 if (!lsk->peer_conn_id)
 424                         return -ENOTCONN;
 425                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 426                 lsa->l2tp_addr = np->daddr;
 427                 if (np->sndflow)
 428                         lsa->l2tp_flowinfo = np->flow_label;
 429         } else {
 430                 if (ipv6_addr_any(&np->rcv_saddr))
 431                         lsa->l2tp_addr = np->saddr;
 432                 else
 433                         lsa->l2tp_addr = np->rcv_saddr;
 434
 435                 lsa->l2tp_conn_id = lsk->conn_id;
 436         }
 437         if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 438                 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 439         *uaddr_len = sizeof(*lsa);
 440         return 0;
 441 }
 442
 443 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 444 {
 445         int rc;
 446
 447         /* Charge it to the socket, dropping if the queue is full. */
 448         rc = sock_queue_rcv_skb(sk, skb);
 449         if (rc < 0)
 450                 goto drop;
 451
 452         return 0;
 453
 454 drop:
 455         IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
 456         kfree_skb(skb);
 457         return -1;
 458 }
 459
 460 static int l2tp_ip6_push_pending_frames(struct sock *sk)
 461 {
 462         struct sk_buff *skb;
 463         __be32 *transhdr = NULL;
 464         int err = 0;
 465
 466         skb = skb_peek(&sk->sk_write_queue);
 467         if (skb == NULL)
 468                 goto out;
 469
 470         transhdr = (__be32 *)skb_transport_header(skb);
 471         *transhdr = 0;
 472
 473         err = ip6_push_pending_frames(sk);
 474
 475 out:
 476         return err;
 477 }
 478
 479 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 480  * control frames.
 481  */
 482 static int l2tp_ip6_sendmsg(struct kiocb *iocb, struct sock *sk,
 483                             struct msghdr *msg, size_t len)
 484 {
 485         struct ipv6_txoptions opt_space;
 486         struct sockaddr_l2tpip6 *lsa =
 487                 (struct sockaddr_l2tpip6 *) msg->msg_name;
 488         struct in6_addr *daddr, *final_p, final;
 489         struct ipv6_pinfo *np = inet6_sk(sk);
 490         struct ipv6_txoptions *opt = NULL;
 491         struct ip6_flowlabel *flowlabel = NULL;
 492         struct dst_entry *dst = NULL;
 493         struct flowi6 fl6;
 494         int addr_len = msg->msg_namelen;
 495         int hlimit = -1;
 496         int tclass = -1;
 497         int dontfrag = -1;
 498         int transhdrlen = 4; /* zero session-id */
 499         int ulen = len + transhdrlen;
 500         int err;
 501
 502         /* Rough check on arithmetic overflow,
 503            better check is made in ip6_append_data().
 504          */
 505         if (len > INT_MAX)
 506                 return -EMSGSIZE;
 507
 508         /* Mirror BSD error message compatibility */
 509         if (msg->msg_flags & MSG_OOB)
 510                 return -EOPNOTSUPP;
 511
 512         /*
 513          *      Get and verify the address.
 514          */
 515         memset(&fl6, 0, sizeof(fl6));
 516
 517         fl6.flowi6_mark = sk->sk_mark;
 518
 519         if (lsa) {
 520                 if (addr_len < SIN6_LEN_RFC2133)
 521                         return -EINVAL;
 522
 523                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 524                         return -EAFNOSUPPORT;
 525
 526                 daddr = &lsa->l2tp_addr;
 527                 if (np->sndflow) {
 528                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 529                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 530                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 531                                 if (flowlabel == NULL)
 532                                         return -EINVAL;
 533                                 daddr = &flowlabel->dst;
 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, &np->daddr))
 543                         daddr = &np->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 = &np->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 == NULL)
 581                 opt = np->opt;
 582         if (flowlabel)
 583                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
 584         opt = ipv6_fixup_options(&opt_space, opt);
 585
 586         fl6.flowi6_proto = sk->sk_protocol;
 587         if (!ipv6_addr_any(daddr))
 588                 fl6.daddr = *daddr;
 589         else
 590                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 591         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 592                 fl6.saddr = np->saddr;
 593
 594         final_p = fl6_update_dst(&fl6, opt, &final);
 595
 596         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 597                 fl6.flowi6_oif = np->mcast_oif;
 598         else if (!fl6.flowi6_oif)
 599                 fl6.flowi6_oif = np->ucast_oif;
 600
 601         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 602
 603         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
 604         if (IS_ERR(dst)) {
 605                 err = PTR_ERR(dst);
 606                 goto out;
 607         }
 608
 609         if (hlimit < 0) {
 610                 if (ipv6_addr_is_multicast(&fl6.daddr))
 611                         hlimit = np->mcast_hops;
 612                 else
 613                         hlimit = np->hop_limit;
 614                 if (hlimit < 0)
 615                         hlimit = ip6_dst_hoplimit(dst);
 616         }
 617
 618         if (tclass < 0)
 619                 tclass = np->tclass;
 620
 621         if (dontfrag < 0)
 622                 dontfrag = np->dontfrag;
 623
 624         if (msg->msg_flags & MSG_CONFIRM)
 625                 goto do_confirm;
 626
 627 back_from_confirm:
 628         lock_sock(sk);
 629         err = ip6_append_data(sk, ip_generic_getfrag, msg->msg_iov,
 630                               ulen, transhdrlen, hlimit, tclass, opt,
 631                               &fl6, (struct rt6_info *)dst,
 632                               msg->msg_flags, dontfrag);
 633         if (err)
 634                 ip6_flush_pending_frames(sk);
 635         else if (!(msg->msg_flags & MSG_MORE))
 636                 err = l2tp_ip6_push_pending_frames(sk);
 637         release_sock(sk);
 638 done:
 639         dst_release(dst);
 640 out:
 641         fl6_sock_release(flowlabel);
 642
 643         return err < 0 ? err : len;
 644
 645 do_confirm:
 646         dst_confirm(dst);
 647         if (!(msg->msg_flags & MSG_PROBE) || len)
 648                 goto back_from_confirm;
 649         err = 0;
 650         goto done;
 651 }
 652
 653 static int l2tp_ip6_recvmsg(struct kiocb *iocb, struct sock *sk,
 654                             struct msghdr *msg, size_t len, int noblock,
 655                             int flags, int *addr_len)
 656 {
 657         struct ipv6_pinfo *np = inet6_sk(sk);
 658         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)msg->msg_name;
 659         size_t copied = 0;
 660         int err = -EOPNOTSUPP;
 661         struct sk_buff *skb;
 662
 663         if (flags & MSG_OOB)
 664                 goto out;
 665
 666         if (addr_len)
 667                 *addr_len = sizeof(*lsa);
 668
 669         if (flags & MSG_ERRQUEUE)
 670                 return ipv6_recv_error(sk, msg, len, addr_len);
 671
 672         skb = skb_recv_datagram(sk, flags, noblock, &err);
 673         if (!skb)
 674                 goto out;
 675
 676         copied = skb->len;
 677         if (len < copied) {
 678                 msg->msg_flags |= MSG_TRUNC;
 679                 copied = len;
 680         }
 681
 682         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 683         if (err)
 684                 goto done;
 685
 686         sock_recv_timestamp(msg, sk, skb);
 687
 688         /* Copy the address. */
 689         if (lsa) {
 690                 lsa->l2tp_family = AF_INET6;
 691                 lsa->l2tp_unused = 0;
 692                 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 693                 lsa->l2tp_flowinfo = 0;
 694                 lsa->l2tp_scope_id = 0;
 695                 lsa->l2tp_conn_id = 0;
 696                 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 697                         lsa->l2tp_scope_id = IP6CB(skb)->iif;
 698         }
 699
 700         if (np->rxopt.all)
 701                 ip6_datagram_recv_ctl(sk, msg, skb);
 702
 703         if (flags & MSG_TRUNC)
 704                 copied = skb->len;
 705 done:
 706         skb_free_datagram(sk, skb);
 707 out:
 708         return err ? err : copied;
 709 }
 710
 711 static struct proto l2tp_ip6_prot = {
 712         .name              = "L2TP/IPv6",
 713         .owner             = THIS_MODULE,
 714         .init              = l2tp_ip6_open,
 715         .close             = l2tp_ip6_close,
 716         .bind              = l2tp_ip6_bind,
 717         .connect           = l2tp_ip6_connect,
 718         .disconnect        = l2tp_ip6_disconnect,
 719         .ioctl             = l2tp_ioctl,
 720         .destroy           = l2tp_ip6_destroy_sock,
 721         .setsockopt        = ipv6_setsockopt,
 722         .getsockopt        = ipv6_getsockopt,
 723         .sendmsg           = l2tp_ip6_sendmsg,
 724         .recvmsg           = l2tp_ip6_recvmsg,
 725         .backlog_rcv       = l2tp_ip6_backlog_recv,
 726         .hash              = inet_hash,
 727         .unhash            = inet_unhash,
 728         .obj_size          = sizeof(struct l2tp_ip6_sock),
 729 #ifdef CONFIG_COMPAT
 730         .compat_setsockopt = compat_ipv6_setsockopt,
 731         .compat_getsockopt = compat_ipv6_getsockopt,
 732 #endif
 733 };
 734
 735 static const struct proto_ops l2tp_ip6_ops = {
 736         .family            = PF_INET6,
 737         .owner             = THIS_MODULE,
 738         .release           = inet6_release,
 739         .bind              = inet6_bind,
 740         .connect           = inet_dgram_connect,
 741         .socketpair        = sock_no_socketpair,
 742         .accept            = sock_no_accept,
 743         .getname           = l2tp_ip6_getname,
 744         .poll              = datagram_poll,
 745         .ioctl             = inet6_ioctl,
 746         .listen            = sock_no_listen,
 747         .shutdown          = inet_shutdown,
 748         .setsockopt        = sock_common_setsockopt,
 749         .getsockopt        = sock_common_getsockopt,
 750         .sendmsg           = inet_sendmsg,
 751         .recvmsg           = sock_common_recvmsg,
 752         .mmap              = sock_no_mmap,
 753         .sendpage          = sock_no_sendpage,
 754 #ifdef CONFIG_COMPAT
 755         .compat_setsockopt = compat_sock_common_setsockopt,
 756         .compat_getsockopt = compat_sock_common_getsockopt,
 757 #endif
 758 };
 759
 760 static struct inet_protosw l2tp_ip6_protosw = {
 761         .type           = SOCK_DGRAM,
 762         .protocol       = IPPROTO_L2TP,
 763         .prot           = &l2tp_ip6_prot,
 764         .ops            = &l2tp_ip6_ops,
 765         .no_check       = 0,
 766 };
 767
 768 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 769         .handler        = l2tp_ip6_recv,
 770 };
 771
 772 static int __init l2tp_ip6_init(void)
 773 {
 774         int err;
 775
 776         pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 777
 778         err = proto_register(&l2tp_ip6_prot, 1);
 779         if (err != 0)
 780                 goto out;
 781
 782         err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 783         if (err)
 784                 goto out1;
 785
 786         inet6_register_protosw(&l2tp_ip6_protosw);
 787         return 0;
 788
 789 out1:
 790         proto_unregister(&l2tp_ip6_prot);
 791 out:
 792         return err;
 793 }
 794
 795 static void __exit l2tp_ip6_exit(void)
 796 {
 797         inet6_unregister_protosw(&l2tp_ip6_protosw);
 798         inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 799         proto_unregister(&l2tp_ip6_prot);
 800 }
 801
 802 module_init(l2tp_ip6_init);
 803 module_exit(l2tp_ip6_exit);
 804
 805 MODULE_LICENSE("GPL");
 806 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 807 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 808 MODULE_VERSION("1.0");
 809
 810 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 811  * enums
 812  */
 813 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);