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 != NULL)
 187                 sk = tunnel->sock;
 188         else {
 189                 struct ipv6hdr *iph = ipv6_hdr(skb);
 190
 191                 read_lock_bh(&l2tp_ip6_lock);
 192                 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
 193                                             inet6_iif(skb), tunnel_id);
 194                 if (!sk) {
 195                         read_unlock_bh(&l2tp_ip6_lock);
 196                         goto discard;
 197                 }
 198
 199                 sock_hold(sk);
 200                 read_unlock_bh(&l2tp_ip6_lock);
 201         }
 202
 203         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 204                 goto discard_put;
 205
 206         nf_reset(skb);
 207
 208         return sk_receive_skb(sk, skb, 1);
 209
 210 discard_put:
 211         sock_put(sk);
 212
 213 discard:
 214         kfree_skb(skb);
 215         return 0;
 216 }
 217
 218 static int l2tp_ip6_open(struct sock *sk)
 219 {
 220         /* Prevent autobind. We don't have ports. */
 221         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 222
 223         write_lock_bh(&l2tp_ip6_lock);
 224         sk_add_node(sk, &l2tp_ip6_table);
 225         write_unlock_bh(&l2tp_ip6_lock);
 226
 227         return 0;
 228 }
 229
 230 static void l2tp_ip6_close(struct sock *sk, long timeout)
 231 {
 232         write_lock_bh(&l2tp_ip6_lock);
 233         hlist_del_init(&sk->sk_bind_node);
 234         sk_del_node_init(sk);
 235         write_unlock_bh(&l2tp_ip6_lock);
 236
 237         sk_common_release(sk);
 238 }
 239
 240 static void l2tp_ip6_destroy_sock(struct sock *sk)
 241 {
 242         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 243
 244         lock_sock(sk);
 245         ip6_flush_pending_frames(sk);
 246         release_sock(sk);
 247
 248         if (tunnel) {
 249                 l2tp_tunnel_closeall(tunnel);
 250                 sock_put(sk);
 251         }
 252
 253         inet6_destroy_sock(sk);
 254 }
 255
 256 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 257 {
 258         struct inet_sock *inet = inet_sk(sk);
 259         struct ipv6_pinfo *np = inet6_sk(sk);
 260         struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
 261         struct net *net = sock_net(sk);
 262         __be32 v4addr = 0;
 263         int bound_dev_if;
 264         int addr_type;
 265         int err;
 266
 267         if (addr->l2tp_family != AF_INET6)
 268                 return -EINVAL;
 269         if (addr_len < sizeof(*addr))
 270                 return -EINVAL;
 271
 272         addr_type = ipv6_addr_type(&addr->l2tp_addr);
 273
 274         /* l2tp_ip6 sockets are IPv6 only */
 275         if (addr_type == IPV6_ADDR_MAPPED)
 276                 return -EADDRNOTAVAIL;
 277
 278         /* L2TP is point-point, not multicast */
 279         if (addr_type & IPV6_ADDR_MULTICAST)
 280                 return -EADDRNOTAVAIL;
 281
 282         lock_sock(sk);
 283
 284         err = -EINVAL;
 285         if (!sock_flag(sk, SOCK_ZAPPED))
 286                 goto out_unlock;
 287
 288         if (sk->sk_state != TCP_CLOSE)
 289                 goto out_unlock;
 290
 291         bound_dev_if = sk->sk_bound_dev_if;
 292
 293         /* Check if the address belongs to the host. */
 294         rcu_read_lock();
 295         if (addr_type != IPV6_ADDR_ANY) {
 296                 struct net_device *dev = NULL;
 297
 298                 if (addr_type & IPV6_ADDR_LINKLOCAL) {
 299                         if (addr->l2tp_scope_id)
 300                                 bound_dev_if = addr->l2tp_scope_id;
 301
 302                         /* Binding to link-local address requires an
 303                          * interface.
 304                          */
 305                         if (!bound_dev_if)
 306                                 goto out_unlock_rcu;
 307
 308                         err = -ENODEV;
 309                         dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
 310                         if (!dev)
 311                                 goto out_unlock_rcu;
 312                 }
 313
 314                 /* ipv4 addr of the socket is invalid.  Only the
 315                  * unspecified and mapped address have a v4 equivalent.
 316                  */
 317                 v4addr = LOOPBACK4_IPV6;
 318                 err = -EADDRNOTAVAIL;
 319                 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
 320                         goto out_unlock_rcu;
 321         }
 322         rcu_read_unlock();
 323
 324         write_lock_bh(&l2tp_ip6_lock);
 325         if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
 326                                    addr->l2tp_conn_id)) {
 327                 write_unlock_bh(&l2tp_ip6_lock);
 328                 err = -EADDRINUSE;
 329                 goto out_unlock;
 330         }
 331
 332         inet->inet_saddr = v4addr;
 333         inet->inet_rcv_saddr = v4addr;
 334         sk->sk_bound_dev_if = bound_dev_if;
 335         sk->sk_v6_rcv_saddr = addr->l2tp_addr;
 336         np->saddr = addr->l2tp_addr;
 337
 338         l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
 339
 340         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 341         sk_del_node_init(sk);
 342         write_unlock_bh(&l2tp_ip6_lock);
 343
 344         sock_reset_flag(sk, SOCK_ZAPPED);
 345         release_sock(sk);
 346         return 0;
 347
 348 out_unlock_rcu:
 349         rcu_read_unlock();
 350 out_unlock:
 351         release_sock(sk);
 352
 353         return err;
 354 }
 355
 356 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
 357                             int addr_len)
 358 {
 359         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
 360         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
 361         struct in6_addr *daddr;
 362         int     addr_type;
 363         int rc;
 364
 365         if (addr_len < sizeof(*lsa))
 366                 return -EINVAL;
 367
 368         if (usin->sin6_family != AF_INET6)
 369                 return -EINVAL;
 370
 371         addr_type = ipv6_addr_type(&usin->sin6_addr);
 372         if (addr_type & IPV6_ADDR_MULTICAST)
 373                 return -EINVAL;
 374
 375         if (addr_type & IPV6_ADDR_MAPPED) {
 376                 daddr = &usin->sin6_addr;
 377                 if (ipv4_is_multicast(daddr->s6_addr32[3]))
 378                         return -EINVAL;
 379         }
 380
 381         lock_sock(sk);
 382
 383          /* Must bind first - autobinding does not work */
 384         if (sock_flag(sk, SOCK_ZAPPED)) {
 385                 rc = -EINVAL;
 386                 goto out_sk;
 387         }
 388
 389         rc = __ip6_datagram_connect(sk, uaddr, addr_len);
 390         if (rc < 0)
 391                 goto out_sk;
 392
 393         l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 394
 395         write_lock_bh(&l2tp_ip6_lock);
 396         hlist_del_init(&sk->sk_bind_node);
 397         sk_add_bind_node(sk, &l2tp_ip6_bind_table);
 398         write_unlock_bh(&l2tp_ip6_lock);
 399
 400 out_sk:
 401         release_sock(sk);
 402
 403         return rc;
 404 }
 405
 406 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
 407 {
 408         if (sock_flag(sk, SOCK_ZAPPED))
 409                 return 0;
 410
 411         return __udp_disconnect(sk, flags);
 412 }
 413
 414 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
 415                             int *uaddr_len, int peer)
 416 {
 417         struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
 418         struct sock *sk = sock->sk;
 419         struct ipv6_pinfo *np = inet6_sk(sk);
 420         struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
 421
 422         lsa->l2tp_family = AF_INET6;
 423         lsa->l2tp_flowinfo = 0;
 424         lsa->l2tp_scope_id = 0;
 425         lsa->l2tp_unused = 0;
 426         if (peer) {
 427                 if (!lsk->peer_conn_id)
 428                         return -ENOTCONN;
 429                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 430                 lsa->l2tp_addr = sk->sk_v6_daddr;
 431                 if (np->sndflow)
 432                         lsa->l2tp_flowinfo = np->flow_label;
 433         } else {
 434                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 435                         lsa->l2tp_addr = np->saddr;
 436                 else
 437                         lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
 438
 439                 lsa->l2tp_conn_id = lsk->conn_id;
 440         }
 441         if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 442                 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
 443         *uaddr_len = sizeof(*lsa);
 444         return 0;
 445 }
 446
 447 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
 448 {
 449         int rc;
 450
 451         /* Charge it to the socket, dropping if the queue is full. */
 452         rc = sock_queue_rcv_skb(sk, skb);
 453         if (rc < 0)
 454                 goto drop;
 455
 456         return 0;
 457
 458 drop:
 459         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 460         kfree_skb(skb);
 461         return -1;
 462 }
 463
 464 static int l2tp_ip6_push_pending_frames(struct sock *sk)
 465 {
 466         struct sk_buff *skb;
 467         __be32 *transhdr = NULL;
 468         int err = 0;
 469
 470         skb = skb_peek(&sk->sk_write_queue);
 471         if (skb == NULL)
 472                 goto out;
 473
 474         transhdr = (__be32 *)skb_transport_header(skb);
 475         *transhdr = 0;
 476
 477         err = ip6_push_pending_frames(sk);
 478
 479 out:
 480         return err;
 481 }
 482
 483 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 484  * control frames.
 485  */
 486 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 487 {
 488         struct ipv6_txoptions opt_space;
 489         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 490         struct in6_addr *daddr, *final_p, final;
 491         struct ipv6_pinfo *np = inet6_sk(sk);
 492         struct ipv6_txoptions *opt_to_free = NULL;
 493         struct ipv6_txoptions *opt = NULL;
 494         struct ip6_flowlabel *flowlabel = NULL;
 495         struct dst_entry *dst = NULL;
 496         struct flowi6 fl6;
 497         struct sockcm_cookie sockc_unused = {0};
 498         struct ipcm6_cookie ipc6;
 499         int addr_len = msg->msg_namelen;
 500         int transhdrlen = 4; /* zero session-id */
 501         int ulen = len + transhdrlen;
 502         int err;
 503
 504         /* Rough check on arithmetic overflow,
 505            better check is made in ip6_append_data().
 506          */
 507         if (len > INT_MAX)
 508                 return -EMSGSIZE;
 509
 510         /* Mirror BSD error message compatibility */
 511         if (msg->msg_flags & MSG_OOB)
 512                 return -EOPNOTSUPP;
 513
 514         /*
 515          *      Get and verify the address.
 516          */
 517         memset(&fl6, 0, sizeof(fl6));
 518
 519         fl6.flowi6_mark = sk->sk_mark;
 520         fl6.flowi6_uid = sk->sk_uid;
 521
 522         ipc6.hlimit = -1;
 523         ipc6.tclass = -1;
 524         ipc6.dontfrag = -1;
 525
 526         if (lsa) {
 527                 if (addr_len < SIN6_LEN_RFC2133)
 528                         return -EINVAL;
 529
 530                 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
 531                         return -EAFNOSUPPORT;
 532
 533                 daddr = &lsa->l2tp_addr;
 534                 if (np->sndflow) {
 535                         fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
 536                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 537                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 538                                 if (flowlabel == NULL)
 539                                         return -EINVAL;
 540                         }
 541                 }
 542
 543                 /*
 544                  * Otherwise it will be difficult to maintain
 545                  * sk->sk_dst_cache.
 546                  */
 547                 if (sk->sk_state == TCP_ESTABLISHED &&
 548                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
 549                         daddr = &sk->sk_v6_daddr;
 550
 551                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 552                     lsa->l2tp_scope_id &&
 553                     ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
 554                         fl6.flowi6_oif = lsa->l2tp_scope_id;
 555         } else {
 556                 if (sk->sk_state != TCP_ESTABLISHED)
 557                         return -EDESTADDRREQ;
 558
 559                 daddr = &sk->sk_v6_daddr;
 560                 fl6.flowlabel = np->flow_label;
 561         }
 562
 563         if (fl6.flowi6_oif == 0)
 564                 fl6.flowi6_oif = sk->sk_bound_dev_if;
 565
 566         if (msg->msg_controllen) {
 567                 opt = &opt_space;
 568                 memset(opt, 0, sizeof(struct ipv6_txoptions));
 569                 opt->tot_len = sizeof(struct ipv6_txoptions);
 570                 ipc6.opt = opt;
 571
 572                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6,
 573                                             &sockc_unused);
 574                 if (err < 0) {
 575                         fl6_sock_release(flowlabel);
 576                         return err;
 577                 }
 578                 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
 579                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 580                         if (flowlabel == NULL)
 581                                 return -EINVAL;
 582                 }
 583                 if (!(opt->opt_nflen|opt->opt_flen))
 584                         opt = NULL;
 585         }
 586
 587         if (!opt) {
 588                 opt = txopt_get(np);
 589                 opt_to_free = opt;
 590         }
 591         if (flowlabel)
 592                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
 593         opt = ipv6_fixup_options(&opt_space, opt);
 594         ipc6.opt = opt;
 595
 596         fl6.flowi6_proto = sk->sk_protocol;
 597         if (!ipv6_addr_any(daddr))
 598                 fl6.daddr = *daddr;
 599         else
 600                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
 601         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
 602                 fl6.saddr = np->saddr;
 603
 604         final_p = fl6_update_dst(&fl6, opt, &final);
 605
 606         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 607                 fl6.flowi6_oif = np->mcast_oif;
 608         else if (!fl6.flowi6_oif)
 609                 fl6.flowi6_oif = np->ucast_oif;
 610
 611         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 612
 613         if (ipc6.tclass < 0)
 614                 ipc6.tclass = np->tclass;
 615
 616         fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 617
 618         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 619         if (IS_ERR(dst)) {
 620                 err = PTR_ERR(dst);
 621                 goto out;
 622         }
 623
 624         if (ipc6.hlimit < 0)
 625                 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 626
 627         if (ipc6.dontfrag < 0)
 628                 ipc6.dontfrag = np->dontfrag;
 629
 630         if (msg->msg_flags & MSG_CONFIRM)
 631                 goto do_confirm;
 632
 633 back_from_confirm:
 634         lock_sock(sk);
 635         err = ip6_append_data(sk, ip_generic_getfrag, msg,
 636                               ulen, transhdrlen, &ipc6,
 637                               &fl6, (struct rt6_info *)dst,
 638                               msg->msg_flags, &sockc_unused);
 639         if (err)
 640                 ip6_flush_pending_frames(sk);
 641         else if (!(msg->msg_flags & MSG_MORE))
 642                 err = l2tp_ip6_push_pending_frames(sk);
 643         release_sock(sk);
 644 done:
 645         dst_release(dst);
 646 out:
 647         fl6_sock_release(flowlabel);
 648         txopt_put(opt_to_free);
 649
 650         return err < 0 ? err : len;
 651
 652 do_confirm:
 653         dst_confirm(dst);
 654         if (!(msg->msg_flags & MSG_PROBE) || len)
 655                 goto back_from_confirm;
 656         err = 0;
 657         goto done;
 658 }
 659
 660 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 661                             int noblock, int flags, int *addr_len)
 662 {
 663         struct ipv6_pinfo *np = inet6_sk(sk);
 664         DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
 665         size_t copied = 0;
 666         int err = -EOPNOTSUPP;
 667         struct sk_buff *skb;
 668
 669         if (flags & MSG_OOB)
 670                 goto out;
 671
 672         if (addr_len)
 673                 *addr_len = sizeof(*lsa);
 674
 675         if (flags & MSG_ERRQUEUE)
 676                 return ipv6_recv_error(sk, msg, len, addr_len);
 677
 678         skb = skb_recv_datagram(sk, flags, noblock, &err);
 679         if (!skb)
 680                 goto out;
 681
 682         copied = skb->len;
 683         if (len < copied) {
 684                 msg->msg_flags |= MSG_TRUNC;
 685                 copied = len;
 686         }
 687
 688         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 689         if (err)
 690                 goto done;
 691
 692         sock_recv_timestamp(msg, sk, skb);
 693
 694         /* Copy the address. */
 695         if (lsa) {
 696                 lsa->l2tp_family = AF_INET6;
 697                 lsa->l2tp_unused = 0;
 698                 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
 699                 lsa->l2tp_flowinfo = 0;
 700                 lsa->l2tp_scope_id = 0;
 701                 lsa->l2tp_conn_id = 0;
 702                 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
 703                         lsa->l2tp_scope_id = inet6_iif(skb);
 704         }
 705
 706         if (np->rxopt.all)
 707                 ip6_datagram_recv_ctl(sk, msg, skb);
 708
 709         if (flags & MSG_TRUNC)
 710                 copied = skb->len;
 711 done:
 712         skb_free_datagram(sk, skb);
 713 out:
 714         return err ? err : copied;
 715 }
 716
 717 static struct proto l2tp_ip6_prot = {
 718         .name              = "L2TP/IPv6",
 719         .owner             = THIS_MODULE,
 720         .init              = l2tp_ip6_open,
 721         .close             = l2tp_ip6_close,
 722         .bind              = l2tp_ip6_bind,
 723         .connect           = l2tp_ip6_connect,
 724         .disconnect        = l2tp_ip6_disconnect,
 725         .ioctl             = udp_ioctl,
 726         .destroy           = l2tp_ip6_destroy_sock,
 727         .setsockopt        = ipv6_setsockopt,
 728         .getsockopt        = ipv6_getsockopt,
 729         .sendmsg           = l2tp_ip6_sendmsg,
 730         .recvmsg           = l2tp_ip6_recvmsg,
 731         .backlog_rcv       = l2tp_ip6_backlog_recv,
 732         .hash              = inet6_hash,
 733         .unhash            = inet_unhash,
 734         .obj_size          = sizeof(struct l2tp_ip6_sock),
 735 #ifdef CONFIG_COMPAT
 736         .compat_setsockopt = compat_ipv6_setsockopt,
 737         .compat_getsockopt = compat_ipv6_getsockopt,
 738 #endif
 739 };
 740
 741 static const struct proto_ops l2tp_ip6_ops = {
 742         .family            = PF_INET6,
 743         .owner             = THIS_MODULE,
 744         .release           = inet6_release,
 745         .bind              = inet6_bind,
 746         .connect           = inet_dgram_connect,
 747         .socketpair        = sock_no_socketpair,
 748         .accept            = sock_no_accept,
 749         .getname           = l2tp_ip6_getname,
 750         .poll              = datagram_poll,
 751         .ioctl             = inet6_ioctl,
 752         .listen            = sock_no_listen,
 753         .shutdown          = inet_shutdown,
 754         .setsockopt        = sock_common_setsockopt,
 755         .getsockopt        = sock_common_getsockopt,
 756         .sendmsg           = inet_sendmsg,
 757         .recvmsg           = sock_common_recvmsg,
 758         .mmap              = sock_no_mmap,
 759         .sendpage          = sock_no_sendpage,
 760 #ifdef CONFIG_COMPAT
 761         .compat_setsockopt = compat_sock_common_setsockopt,
 762         .compat_getsockopt = compat_sock_common_getsockopt,
 763 #endif
 764 };
 765
 766 static struct inet_protosw l2tp_ip6_protosw = {
 767         .type           = SOCK_DGRAM,
 768         .protocol       = IPPROTO_L2TP,
 769         .prot           = &l2tp_ip6_prot,
 770         .ops            = &l2tp_ip6_ops,
 771 };
 772
 773 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
 774         .handler        = l2tp_ip6_recv,
 775 };
 776
 777 static int __init l2tp_ip6_init(void)
 778 {
 779         int err;
 780
 781         pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
 782
 783         err = proto_register(&l2tp_ip6_prot, 1);
 784         if (err != 0)
 785                 goto out;
 786
 787         err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 788         if (err)
 789                 goto out1;
 790
 791         inet6_register_protosw(&l2tp_ip6_protosw);
 792         return 0;
 793
 794 out1:
 795         proto_unregister(&l2tp_ip6_prot);
 796 out:
 797         return err;
 798 }
 799
 800 static void __exit l2tp_ip6_exit(void)
 801 {
 802         inet6_unregister_protosw(&l2tp_ip6_protosw);
 803         inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
 804         proto_unregister(&l2tp_ip6_prot);
 805 }
 806
 807 module_init(l2tp_ip6_init);
 808 module_exit(l2tp_ip6_exit);
 809
 810 MODULE_LICENSE("GPL");
 811 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
 812 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
 813 MODULE_VERSION("1.0");
 814
 815 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 816  * enums
 817  */
 818 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
 819 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);