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 ((l2tp->conn_id == tunnel_id) &&
  73                     net_eq(sock_net(sk), net) &&
  74                     (!sk_laddr || ipv6_addr_any(sk_laddr) || ipv6_addr_equal(sk_laddr, laddr)) &&
  75                     (!raddr || ipv6_addr_any(sk_raddr) || ipv6_addr_equal(sk_raddr, raddr)) &&
  76                     (!sk->sk_bound_dev_if || !dif ||
  77                      sk->sk_bound_dev_if == dif))
  78                         goto found;
  79         }
  80
  81         sk = NULL;
  82 found:
  83         return sk;
  84 }
  85
  86 /* When processing receive frames, there are two cases to
  87  * consider. Data frames consist of a non-zero session-id and an
  88  * optional cookie. Control frames consist of a regular L2TP header
  89  * preceded by 32-bits of zeros.
  90  *
  91  * L2TPv3 Session Header Over IP
  92  *
  93  *  0                   1                   2                   3
  94  *  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
  95  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  96  * |                           Session ID                          |
  97  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  98  * |               Cookie (optional, maximum 64 bits)...
  99  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 100  *                                                                 |
 101  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 102  *
 103  * L2TPv3 Control Message Header Over IP
 104  *
 105  *  0                   1                   2                   3
 106  *  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
 107  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 108  * |                      (32 bits of zeros)                       |
 109  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 110  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 111  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 112  * |                     Control Connection ID                     |
 113  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 114  * |               Ns              |               Nr              |
 115  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 116  *
 117  * All control frames are passed to userspace.
 118  */
 119 static int l2tp_ip6_recv(struct sk_buff *skb)
 120 {
 121         struct net *net = dev_net(skb->dev);
 122         struct sock *sk;
 123         u32 session_id;
 124         u32 tunnel_id;
 125         unsigned char *ptr, *optr;
 126         struct l2tp_session *session;
 127         struct l2tp_tunnel *tunnel = NULL;
 128         int length;
 129
 130         if (!pskb_may_pull(skb, 4))
 131                 goto discard;
 132
 133         /* Point to L2TP header */
 134         optr = ptr = skb->data;
 135         session_id = ntohl(*((__be32 *) ptr));
 136         ptr += 4;
 137
 138         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 139          * the session_id. If it is 0, the packet is a L2TP control
 140          * frame and the session_id value can be discarded.
 141          */
 142         if (session_id == 0) {
 143                 __skb_pull(skb, 4);
 144                 goto pass_up;
 145         }
 146
 147         /* Ok, this is a data packet. Lookup the session. */
 148         session = l2tp_session_find(net, NULL, session_id);
 149         if (session == NULL)
 150                 goto discard;
 151
 152         tunnel = session->tunnel;
 153         if (tunnel == NULL)
 154                 goto discard;
 155
 156         /* Trace packet contents, if enabled */
 157         if (tunnel->debug & L2TP_MSG_DATA) {
 158                 length = min(32u, skb->len);
 159                 if (!pskb_may_pull(skb, length))
 160                         goto discard;
 161
 162                 /* Point to L2TP header */
 163                 optr = ptr = skb->data;
 164                 ptr += 4;
 165                 pr_debug("%s: ip recv\n", tunnel->name);
 166                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 167         }
 168
 169         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
 170                          tunnel->recv_payload_hook);
 171         return 0;
 172
 173 pass_up:
 174         /* Get the tunnel_id from the L2TP header */
 175         if (!pskb_may_pull(skb, 12))
 176                 goto discard;
 177
 178         if ((skb->data[0] & 0xc0) != 0xc0)
 179                 goto discard;
 180
 181         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 182         tunnel = l2tp_tunnel_find(net, tunnel_id);
 183         if (tunnel != NULL)
 184                 sk = tunnel->sock;
 185         else {
 186                 struct ipv6hdr *iph = ipv6_hdr(skb);
 187
 188                 read_lock_bh(&l2tp_ip6_lock);
 189                 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
 190                                             inet6_iif(skb), tunnel_id);
 191                 if (!sk) {
 192                         read_unlock_bh(&l2tp_ip6_lock);
 193                         goto discard;
 194                 }
 195
 196                 sock_hold(sk);
 197                 read_unlock_bh(&l2tp_ip6_lock);
 198         }
 199
 200         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 201                 goto discard_put;
 202
 203         nf_reset(skb);
 204
 205         return sk_receive_skb(sk, skb, 1);
 206
 207 discard_put:
 208         sock_put(sk);
 209
 210 discard:
 211         kfree_skb(skb);
 212         return 0;
 213 }
 214
 215 static int l2tp_ip6_open(struct sock *sk)
 216 {
 217         /* Prevent autobind. We don't have ports. */
 218         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 219
 220         write_lock_bh(&l2tp_ip6_lock);
 221         sk_add_node(sk, &l2tp_ip6_table);
 222         write_unlock_bh(&l2tp_ip6_lock);
 223
 224         return 0;
 225 }
 226
 227 static void l2tp_ip6_close(struct sock *sk, long timeout)
 228 {
 229         write_lock_bh(&l2tp_ip6_lock);
 230         hlist_del_init(&sk->sk_bind_node);
 231         sk_del_node_init(sk);
 232         write_unlock_bh(&l2tp_ip6_lock);
 233
 234         sk_common_release(sk);
 235 }
 236
 237 static void l2tp_ip6_destroy_sock(struct sock *sk)
 238 {
 239         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 240
 241         lock_sock(sk);
 242         ip6_flush_pending_frames(sk);
 243         release_sock(sk);
 244
 245         if (tunnel) {
 246                 l2tp_tunnel_closeall(tunnel);
 247                 sock_put(sk);
 248         }
 249
 250         inet6_destroy_sock(sk);
 251 }
 252
 253 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 254 {
 255         struct inet_sock *inet = inet_sk(sk);
 256         struct ipv6_pinfo *np = inet6_sk(sk);
 257         struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
 258         struct net *net = sock_net(sk);
 259         __be32 v4addr = 0;
 260         int bound_dev_if;
 261         int addr_type;
 262         int err;
 263
 264         if (addr->l2tp_family != AF_INET6)
 265                 return -EINVAL;
 266         if (addr_len < sizeof(*addr))
 267                 return -EINVAL;
 268
 269         addr_type = ipv6_addr_type(&addr->l2tp_addr);
 270
 271         /* l2tp_ip6 sockets are IPv6 only */
 272         if (addr_type == IPV6_ADDR_MAPPED)
 273                 return -EADDRNOTAVAIL;
 274
 275         /* L2TP is point-point, not multicast */
 276         if (addr_type & IPV6_ADDR_MULTICAST)
 277                 return -EADDRNOTAVAIL;
 278
 279         lock_sock(sk);
 280
 281         err = -EINVAL;
 282         if (!sock_flag(sk, SOCK_ZAPPED))
 283                 goto out_unlock;
 284
 285         if (sk->sk_state != TCP_CLOSE)
 286                 goto out_unlock;
 287
 288         bound_dev_if = sk->sk_bound_dev_if;
 289
 290         /* Check if the address belongs to the host. */
 291         rcu_read_lock();
 292         if (addr_type != IPV6_ADDR_ANY) {
 293                 struct net_device *dev = NULL;
 294
 295                 if (addr_type & IPV6_ADDR_LINKLOCAL) {
 296                         if (addr->l2tp_scope_id)
 297                                 bound_dev_if = addr->l2tp_scope_id;
 298
 299                         /* Binding to link-local address requires an
 300                          * interface.
 301                          */
 302                         if (!bound_dev_if)
 303                                 goto out_unlock_rcu;
 304
 305                         err = -ENODEV;
 306                         dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
 307                         if (!dev)
 308                                 goto out_unlock_rcu;
 309                 }
 310
 311                 /* ipv4 addr of the socket is invalid.  Only the
 312                  * unspecified and mapped address have a v4 equivalent.
 313                  */
 314                 v4addr = LOOPBACK4_IPV6;
 315                 err = -EADDRNOTAVAIL;
 316                 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
 317                         goto out_unlock_rcu;
 318         }
 319         rcu_read_unlock();
 320
 321         write_lock_bh(&l2tp_ip6_lock);
 322         if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
 323                                    addr->l2tp_conn_id)) {
 324                 write_unlock_bh(&l2tp_ip6_lock);
 325                 err = -EADDRINUSE;
 326                 goto out_unlock;
 327         }
 328
 329         inet->inet_saddr = v4addr;
 330         inet->inet_rcv_saddr = v4addr;
 331         sk->sk_bound_dev_if = bound_dev_if;
 332         sk->sk_v6_rcv_saddr = addr->l2tp_addr;
 333         np->saddr = addr->l2tp_addr;
 334
 335         l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
 336
 337         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 338         sk_del_node_init(sk);
 339         write_unlock_bh(&l2tp_ip6_lock);
 340
 341         sock_reset_flag(sk, SOCK_ZAPPED);
 342         release_sock(sk);
 343         return 0;
 344
 345 out_unlock_rcu:
 346         rcu_read_unlock();
 347 out_unlock:
 348         release_sock(sk);
 349
 350         return err;
 351 }
 352
 353 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 354                             int addr_len)
 355 {
 356         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 357         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 358         struct in6_addr *daddr;
 359         int     addr_type;
 360         int rc;
 361
 362         if (addr_len < sizeof(*lsa))
 363                 return -EINVAL;
 364
 365         if (usin->sin6_family != AF_INET6)
 366                 return -EINVAL;
 367
 368         addr_type = ipv6_addr_type(&usin->sin6_addr);
 369         if (addr_type & IPV6_ADDR_MULTICAST)
 370                 return -EINVAL;
 371
 372         if (addr_type & IPV6_ADDR_MAPPED) {
 373                 daddr = &usin->sin6_addr;
 374                 if (ipv4_is_multicast(daddr->s6_addr32[3]))
 375                         return -EINVAL;
 376         }
 377
 378         lock_sock(sk);
 379
 380          /* Must bind first - autobinding does not work */
 381         if (sock_flag(sk, SOCK_ZAPPED)) {
 382                 rc = -EINVAL;
 383                 goto out_sk;
 384         }
 385
 386         rc = __ip6_datagram_connect(sk, uaddr, addr_len);
 387         if (rc < 0)
 388                 goto out_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 out_sk:
 398         release_sock(sk);
 399
 400         return rc;
 401 }
 402
 403 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 404 {
 405         if (sock_flag(sk, SOCK_ZAPPED))
 406                 return 0;
 407
 408         return __udp_disconnect(sk, flags);
 409 }
 410
 411 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 412                             int *uaddr_len, int peer)
 413 {
 414         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 415         struct sock *sk = sock->sk;
 416         struct ipv6_pinfo *np = inet6_sk(sk);
 417         struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 418
 419         lsa->l2tp_family = AF_INET6;
 420         lsa->l2tp_flowinfo = 0;
 421         lsa->l2tp_scope_id = 0;
 422         lsa->l2tp_unused = 0;
 423         if (peer) {
 424                 if (!lsk->peer_conn_id)
 425                         return -ENOTCONN;
 426                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 427                 lsa->l2tp_addr = sk->sk_v6_daddr;
 428                 if (np->sndflow)
 429                         lsa->l2tp_flowinfo = np->flow_label;
 430         } else {
 431                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 432                         lsa->l2tp_addr = np->saddr;
 433                 else
 434                         lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
 435
 436                 lsa->l2tp_conn_id = lsk->conn_id;
 437         }
 438         if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 439                 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 440         *uaddr_len = sizeof(*lsa);
 441         return 0;
 442 }
 443
 444 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 445 {
 446         int rc;
 447
 448         /* Charge it to the socket, dropping if the queue is full. */
 449         rc = sock_queue_rcv_skb(sk, skb);
 450         if (rc < 0)
 451                 goto drop;
 452
 453         return 0;
 454
 455 drop:
 456         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 457         kfree_skb(skb);
 458         return -1;
 459 }
 460
 461 static int l2tp_ip6_push_pending_frames(struct sock *sk)
 462 {
 463         struct sk_buff *skb;
 464         __be32 *transhdr = NULL;
 465         int err = 0;
 466
 467         skb = skb_peek(&sk->sk_write_queue);
 468         if (skb == NULL)
 469                 goto out;
 470
 471         transhdr = (__be32 *)skb_transport_header(skb);
 472         *transhdr = 0;
 473
 474         err = ip6_push_pending_frames(sk);
 475
 476 out:
 477         return err;
 478 }
 479
 480 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 481  * control frames.
 482  */
 483 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 484 {
 485         struct ipv6_txoptions opt_space;
 486         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 487         struct in6_addr *daddr, *final_p, final;
 488         struct ipv6_pinfo *np = inet6_sk(sk);
 489         struct ipv6_txoptions *opt_to_free = NULL;
 490         struct ipv6_txoptions *opt = NULL;
 491         struct ip6_flowlabel *flowlabel = NULL;
 492         struct dst_entry *dst = NULL;
 493         struct flowi6 fl6;
 494         struct sockcm_cookie sockc_unused = {0};
 495         struct ipcm6_cookie ipc6;
 496         int addr_len = msg->msg_namelen;
 497         int transhdrlen = 4; /* zero session-id */
 498         int ulen = len + transhdrlen;
 499         int err;
 500
 501         /* Rough check on arithmetic overflow,
 502            better check is made in ip6_append_data().
 503          */
 504         if (len > INT_MAX)
 505                 return -EMSGSIZE;
 506
 507         /* Mirror BSD error message compatibility */
 508         if (msg->msg_flags & MSG_OOB)
 509                 return -EOPNOTSUPP;
 510
 511         /*
 512          *      Get and verify the address.
 513          */
 514         memset(&fl6, 0, sizeof(fl6));
 515
 516         fl6.flowi6_mark = sk->sk_mark;
 517         fl6.flowi6_uid = sk->sk_uid;
 518
 519         ipc6.hlimit = -1;
 520         ipc6.tclass = -1;
 521         ipc6.dontfrag = -1;
 522
 523         if (lsa) {
 524                 if (addr_len < SIN6_LEN_RFC2133)
 525                         return -EINVAL;
 526
 527                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 528                         return -EAFNOSUPPORT;
 529
 530                 daddr = &lsa->l2tp_addr;
 531                 if (np->sndflow) {
 532                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 533                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 534                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 535                                 if (flowlabel == NULL)
 536                                         return -EINVAL;
 537                         }
 538                 }
 539
 540                 /*
 541                  * Otherwise it will be difficult to maintain
 542                  * sk->sk_dst_cache.
 543                  */
 544                 if (sk->sk_state == TCP_ESTABLISHED &&
 545                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
 546                         daddr = &sk->sk_v6_daddr;
 547
 548                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 549                     lsa->l2tp_scope_id &&
 550                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 551                         fl6.flowi6_oif = lsa->l2tp_scope_id;
 552         } else {
 553                 if (sk->sk_state != TCP_ESTABLISHED)
 554                         return -EDESTADDRREQ;
 555
 556                 daddr = &sk->sk_v6_daddr;
 557                 fl6.flowlabel = np->flow_label;
 558         }
 559
 560         if (fl6.flowi6_oif == 0)
 561                 fl6.flowi6_oif = sk->sk_bound_dev_if;
 562
 563         if (msg->msg_controllen) {
 564                 opt = &opt_space;
 565                 memset(opt, 0, sizeof(struct ipv6_txoptions));
 566                 opt->tot_len = sizeof(struct ipv6_txoptions);
 567                 ipc6.opt = opt;
 568
 569                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6,
 570                                             &sockc_unused);
 571                 if (err < 0) {
 572                         fl6_sock_release(flowlabel);
 573                         return err;
 574                 }
 575                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 576                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 577                         if (flowlabel == NULL)
 578                                 return -EINVAL;
 579                 }
 580                 if (!(opt->opt_nflen|opt->opt_flen))
 581                         opt = NULL;
 582         }
 583
 584         if (!opt) {
 585                 opt = txopt_get(np);
 586                 opt_to_free = opt;
 587         }
 588         if (flowlabel)
 589                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
 590         opt = ipv6_fixup_options(&opt_space, opt);
 591         ipc6.opt = opt;
 592
 593         fl6.flowi6_proto = sk->sk_protocol;
 594         if (!ipv6_addr_any(daddr))
 595                 fl6.daddr = *daddr;
 596         else
 597                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 598         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 599                 fl6.saddr = np->saddr;
 600
 601         final_p = fl6_update_dst(&fl6, opt, &final);
 602
 603         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 604                 fl6.flowi6_oif = np->mcast_oif;
 605         else if (!fl6.flowi6_oif)
 606                 fl6.flowi6_oif = np->ucast_oif;
 607
 608         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 609
 610         if (ipc6.tclass < 0)
 611                 ipc6.tclass = np->tclass;
 612
 613         fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 614
 615         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 616         if (IS_ERR(dst)) {
 617                 err = PTR_ERR(dst);
 618                 goto out;
 619         }
 620
 621         if (ipc6.hlimit < 0)
 622                 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 623
 624         if (ipc6.dontfrag < 0)
 625                 ipc6.dontfrag = np->dontfrag;
 626
 627         if (msg->msg_flags & MSG_CONFIRM)
 628                 goto do_confirm;
 629
 630 back_from_confirm:
 631         lock_sock(sk);
 632         err = ip6_append_data(sk, ip_generic_getfrag, msg,
 633                               ulen, transhdrlen, &ipc6,
 634                               &fl6, (struct rt6_info *)dst,
 635                               msg->msg_flags, &sockc_unused);
 636         if (err)
 637                 ip6_flush_pending_frames(sk);
 638         else if (!(msg->msg_flags & MSG_MORE))
 639                 err = l2tp_ip6_push_pending_frames(sk);
 640         release_sock(sk);
 641 done:
 642         dst_release(dst);
 643 out:
 644         fl6_sock_release(flowlabel);
 645         txopt_put(opt_to_free);
 646
 647         return err < 0 ? err : len;
 648
 649 do_confirm:
 650         dst_confirm(dst);
 651         if (!(msg->msg_flags & MSG_PROBE) || len)
 652                 goto back_from_confirm;
 653         err = 0;
 654         goto done;
 655 }
 656
 657 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 658                             int noblock, int flags, int *addr_len)
 659 {
 660         struct ipv6_pinfo *np = inet6_sk(sk);
 661         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 662         size_t copied = 0;
 663         int err = -EOPNOTSUPP;
 664         struct sk_buff *skb;
 665
 666         if (flags & MSG_OOB)
 667                 goto out;
 668
 669         if (addr_len)
 670                 *addr_len = sizeof(*lsa);
 671
 672         if (flags & MSG_ERRQUEUE)
 673                 return ipv6_recv_error(sk, msg, len, addr_len);
 674
 675         skb = skb_recv_datagram(sk, flags, noblock, &err);
 676         if (!skb)
 677                 goto out;
 678
 679         copied = skb->len;
 680         if (len < copied) {
 681                 msg->msg_flags |= MSG_TRUNC;
 682                 copied = len;
 683         }
 684
 685         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 686         if (err)
 687                 goto done;
 688
 689         sock_recv_timestamp(msg, sk, skb);
 690
 691         /* Copy the address. */
 692         if (lsa) {
 693                 lsa->l2tp_family = AF_INET6;
 694                 lsa->l2tp_unused = 0;
 695                 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 696                 lsa->l2tp_flowinfo = 0;
 697                 lsa->l2tp_scope_id = 0;
 698                 lsa->l2tp_conn_id = 0;
 699                 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 700                         lsa->l2tp_scope_id = inet6_iif(skb);
 701         }
 702
 703         if (np->rxopt.all)
 704                 ip6_datagram_recv_ctl(sk, msg, skb);
 705
 706         if (flags & MSG_TRUNC)
 707                 copied = skb->len;
 708 done:
 709         skb_free_datagram(sk, skb);
 710 out:
 711         return err ? err : copied;
 712 }
 713
 714 static struct proto l2tp_ip6_prot = {
 715         .name              = "L2TP/IPv6",
 716         .owner             = THIS_MODULE,
 717         .init              = l2tp_ip6_open,
 718         .close             = l2tp_ip6_close,
 719         .bind              = l2tp_ip6_bind,
 720         .connect           = l2tp_ip6_connect,
 721         .disconnect        = l2tp_ip6_disconnect,
 722         .ioctl             = udp_ioctl,
 723         .destroy           = l2tp_ip6_destroy_sock,
 724         .setsockopt        = ipv6_setsockopt,
 725         .getsockopt        = ipv6_getsockopt,
 726         .sendmsg           = l2tp_ip6_sendmsg,
 727         .recvmsg           = l2tp_ip6_recvmsg,
 728         .backlog_rcv       = l2tp_ip6_backlog_recv,
 729         .hash              = inet6_hash,
 730         .unhash            = inet_unhash,
 731         .obj_size          = sizeof(struct l2tp_ip6_sock),
 732 #ifdef CONFIG_COMPAT
 733         .compat_setsockopt = compat_ipv6_setsockopt,
 734         .compat_getsockopt = compat_ipv6_getsockopt,
 735 #endif
 736 };
 737
 738 static const struct proto_ops l2tp_ip6_ops = {
 739         .family            = PF_INET6,
 740         .owner             = THIS_MODULE,
 741         .release           = inet6_release,
 742         .bind              = inet6_bind,
 743         .connect           = inet_dgram_connect,
 744         .socketpair        = sock_no_socketpair,
 745         .accept            = sock_no_accept,
 746         .getname           = l2tp_ip6_getname,
 747         .poll              = datagram_poll,
 748         .ioctl             = inet6_ioctl,
 749         .listen            = sock_no_listen,
 750         .shutdown          = inet_shutdown,
 751         .setsockopt        = sock_common_setsockopt,
 752         .getsockopt        = sock_common_getsockopt,
 753         .sendmsg           = inet_sendmsg,
 754         .recvmsg           = sock_common_recvmsg,
 755         .mmap              = sock_no_mmap,
 756         .sendpage          = sock_no_sendpage,
 757 #ifdef CONFIG_COMPAT
 758         .compat_setsockopt = compat_sock_common_setsockopt,
 759         .compat_getsockopt = compat_sock_common_getsockopt,
 760 #endif
 761 };
 762
 763 static struct inet_protosw l2tp_ip6_protosw = {
 764         .type           = SOCK_DGRAM,
 765         .protocol       = IPPROTO_L2TP,
 766         .prot           = &l2tp_ip6_prot,
 767         .ops            = &l2tp_ip6_ops,
 768 };
 769
 770 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 771         .handler        = l2tp_ip6_recv,
 772 };
 773
 774 static int __init l2tp_ip6_init(void)
 775 {
 776         int err;
 777
 778         pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 779
 780         err = proto_register(&l2tp_ip6_prot, 1);
 781         if (err != 0)
 782                 goto out;
 783
 784         err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 785         if (err)
 786                 goto out1;
 787
 788         inet6_register_protosw(&l2tp_ip6_protosw);
 789         return 0;
 790
 791 out1:
 792         proto_unregister(&l2tp_ip6_prot);
 793 out:
 794         return err;
 795 }
 796
 797 static void __exit l2tp_ip6_exit(void)
 798 {
 799         inet6_unregister_protosw(&l2tp_ip6_protosw);
 800         inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 801         proto_unregister(&l2tp_ip6_prot);
 802 }
 803
 804 module_init(l2tp_ip6_init);
 805 module_exit(l2tp_ip6_exit);
 806
 807 MODULE_LICENSE("GPL");
 808 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 809 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 810 MODULE_VERSION("1.0");
 811
 812 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 813  * enums
 814  */
 815 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
 816 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);