net/l2tp/l2tp_ip.c

   1 /*
   2  * L2TPv3 IP encapsulation support
   3  *
   4  * Copyright (c) 2008,2009,2010 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 <asm/ioctls.h>
  15 #include <linux/icmp.h>
  16 #include <linux/module.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/random.h>
  19 #include <linux/socket.h>
  20 #include <linux/l2tp.h>
  21 #include <linux/in.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 "l2tp_core.h"
  33
  34 struct l2tp_ip_sock {
  35         /* inet_sock has to be the first member of l2tp_ip_sock */
  36         struct inet_sock        inet;
  37
  38         u32                     conn_id;
  39         u32                     peer_conn_id;
  40 };
  41
  42 static DEFINE_RWLOCK(l2tp_ip_lock);
  43 static struct hlist_head l2tp_ip_table;
  44 static struct hlist_head l2tp_ip_bind_table;
  45
  46 static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
  47 {
  48         return (struct l2tp_ip_sock *)sk;
  49 }
  50
  51 static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
  52                                           __be32 raddr, int dif, u32 tunnel_id)
  53 {
  54         struct sock *sk;
  55
  56         sk_for_each_bound(sk, &l2tp_ip_bind_table) {
  57                 struct inet_sock *inet = inet_sk(sk);
  58                 struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
  59
  60                 if (l2tp == NULL)
  61                         continue;
  62
  63                 if ((l2tp->conn_id == tunnel_id) &&
  64                     net_eq(sock_net(sk), net) &&
  65                     !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
  66                     (!inet->inet_daddr || !raddr || inet->inet_daddr == raddr) &&
  67                     (!sk->sk_bound_dev_if || !dif ||
  68                      sk->sk_bound_dev_if == dif))
  69                         goto found;
  70         }
  71
  72         sk = NULL;
  73 found:
  74         return sk;
  75 }
  76
  77 /* When processing receive frames, there are two cases to
  78  * consider. Data frames consist of a non-zero session-id and an
  79  * optional cookie. Control frames consist of a regular L2TP header
  80  * preceded by 32-bits of zeros.
  81  *
  82  * L2TPv3 Session Header Over IP
  83  *
  84  *  0                   1                   2                   3
  85  *  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
  86  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  87  * |                           Session ID                          |
  88  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  89  * |               Cookie (optional, maximum 64 bits)...
  90  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  91  *                                                                 |
  92  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  93  *
  94  * L2TPv3 Control Message 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  * |                      (32 bits of zeros)                       |
 100  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 101  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 102  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 103  * |                     Control Connection ID                     |
 104  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 105  * |               Ns              |               Nr              |
 106  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 107  *
 108  * All control frames are passed to userspace.
 109  */
 110 static int l2tp_ip_recv(struct sk_buff *skb)
 111 {
 112         struct net *net = dev_net(skb->dev);
 113         struct sock *sk;
 114         u32 session_id;
 115         u32 tunnel_id;
 116         unsigned char *ptr, *optr;
 117         struct l2tp_session *session;
 118         struct l2tp_tunnel *tunnel = NULL;
 119         int length;
 120
 121         if (!pskb_may_pull(skb, 4))
 122                 goto discard;
 123
 124         /* Point to L2TP header */
 125         optr = ptr = skb->data;
 126         session_id = ntohl(*((__be32 *) ptr));
 127         ptr += 4;
 128
 129         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 130          * the session_id. If it is 0, the packet is a L2TP control
 131          * frame and the session_id value can be discarded.
 132          */
 133         if (session_id == 0) {
 134                 __skb_pull(skb, 4);
 135                 goto pass_up;
 136         }
 137
 138         /* Ok, this is a data packet. Lookup the session. */
 139         session = l2tp_session_get(net, NULL, session_id, true);
 140         if (!session)
 141                 goto discard;
 142
 143         tunnel = session->tunnel;
 144         if (!tunnel)
 145                 goto discard_sess;
 146
 147         /* Trace packet contents, if enabled */
 148         if (tunnel->debug & L2TP_MSG_DATA) {
 149                 length = min(32u, skb->len);
 150                 if (!pskb_may_pull(skb, length))
 151                         goto discard_sess;
 152
 153                 /* Point to L2TP header */
 154                 optr = ptr = skb->data;
 155                 ptr += 4;
 156                 pr_debug("%s: ip recv\n", tunnel->name);
 157                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 158         }
 159
 160         if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
 161                 goto discard_sess;
 162
 163         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
 164         l2tp_session_dec_refcount(session);
 165
 166         return 0;
 167
 168 pass_up:
 169         /* Get the tunnel_id from the L2TP header */
 170         if (!pskb_may_pull(skb, 12))
 171                 goto discard;
 172
 173         if ((skb->data[0] & 0xc0) != 0xc0)
 174                 goto discard;
 175
 176         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 177         tunnel = l2tp_tunnel_find(net, tunnel_id);
 178         if (tunnel) {
 179                 sk = tunnel->sock;
 180                 sock_hold(sk);
 181         } else {
 182                 struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
 183
 184                 read_lock_bh(&l2tp_ip_lock);
 185                 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr,
 186                                            inet_iif(skb), tunnel_id);
 187                 if (!sk) {
 188                         read_unlock_bh(&l2tp_ip_lock);
 189                         goto discard;
 190                 }
 191
 192                 sock_hold(sk);
 193                 read_unlock_bh(&l2tp_ip_lock);
 194         }
 195
 196         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 197                 goto discard_put;
 198
 199         nf_reset(skb);
 200
 201         return sk_receive_skb(sk, skb, 1);
 202
 203 discard_sess:
 204         if (session->deref)
 205                 session->deref(session);
 206         l2tp_session_dec_refcount(session);
 207         goto discard;
 208
 209 discard_put:
 210         sock_put(sk);
 211
 212 discard:
 213         kfree_skb(skb);
 214         return 0;
 215 }
 216
 217 static int l2tp_ip_open(struct sock *sk)
 218 {
 219         /* Prevent autobind. We don't have ports. */
 220         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 221
 222         write_lock_bh(&l2tp_ip_lock);
 223         sk_add_node(sk, &l2tp_ip_table);
 224         write_unlock_bh(&l2tp_ip_lock);
 225
 226         return 0;
 227 }
 228
 229 static void l2tp_ip_close(struct sock *sk, long timeout)
 230 {
 231         write_lock_bh(&l2tp_ip_lock);
 232         hlist_del_init(&sk->sk_bind_node);
 233         sk_del_node_init(sk);
 234         write_unlock_bh(&l2tp_ip_lock);
 235         sk_common_release(sk);
 236 }
 237
 238 static void l2tp_ip_destroy_sock(struct sock *sk)
 239 {
 240         struct sk_buff *skb;
 241         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 242
 243         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 244                 kfree_skb(skb);
 245
 246         if (tunnel) {
 247                 l2tp_tunnel_closeall(tunnel);
 248                 sock_put(sk);
 249         }
 250
 251         sk_refcnt_debug_dec(sk);
 252 }
 253
 254 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 255 {
 256         struct inet_sock *inet = inet_sk(sk);
 257         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 258         struct net *net = sock_net(sk);
 259         int ret;
 260         int chk_addr_ret;
 261
 262         if (addr_len < sizeof(struct sockaddr_l2tpip))
 263                 return -EINVAL;
 264         if (addr->l2tp_family != AF_INET)
 265                 return -EINVAL;
 266
 267         lock_sock(sk);
 268
 269         ret = -EINVAL;
 270         if (!sock_flag(sk, SOCK_ZAPPED))
 271                 goto out;
 272
 273         if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
 274                 goto out;
 275
 276         chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
 277         ret = -EADDRNOTAVAIL;
 278         if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
 279             chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 280                 goto out;
 281
 282         if (addr->l2tp_addr.s_addr)
 283                 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
 284         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 285                 inet->inet_saddr = 0;  /* Use device */
 286
 287         write_lock_bh(&l2tp_ip_lock);
 288         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
 289                                   sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
 290                 write_unlock_bh(&l2tp_ip_lock);
 291                 ret = -EADDRINUSE;
 292                 goto out;
 293         }
 294
 295         sk_dst_reset(sk);
 296         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 297
 298         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 299         sk_del_node_init(sk);
 300         write_unlock_bh(&l2tp_ip_lock);
 301
 302         ret = 0;
 303         sock_reset_flag(sk, SOCK_ZAPPED);
 304
 305 out:
 306         release_sock(sk);
 307
 308         return ret;
 309 }
 310
 311 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 312 {
 313         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 314         int rc;
 315
 316         if (addr_len < sizeof(*lsa))
 317                 return -EINVAL;
 318
 319         if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 320                 return -EINVAL;
 321
 322         lock_sock(sk);
 323
 324         /* Must bind first - autobinding does not work */
 325         if (sock_flag(sk, SOCK_ZAPPED)) {
 326                 rc = -EINVAL;
 327                 goto out_sk;
 328         }
 329
 330         rc = __ip4_datagram_connect(sk, uaddr, addr_len);
 331         if (rc < 0)
 332                 goto out_sk;
 333
 334         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 335
 336         write_lock_bh(&l2tp_ip_lock);
 337         hlist_del_init(&sk->sk_bind_node);
 338         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 339         write_unlock_bh(&l2tp_ip_lock);
 340
 341 out_sk:
 342         release_sock(sk);
 343
 344         return rc;
 345 }
 346
 347 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 348 {
 349         if (sock_flag(sk, SOCK_ZAPPED))
 350                 return 0;
 351
 352         return __udp_disconnect(sk, flags);
 353 }
 354
 355 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 356                            int *uaddr_len, int peer)
 357 {
 358         struct sock *sk         = sock->sk;
 359         struct inet_sock *inet  = inet_sk(sk);
 360         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 361         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 362
 363         memset(lsa, 0, sizeof(*lsa));
 364         lsa->l2tp_family = AF_INET;
 365         if (peer) {
 366                 if (!inet->inet_dport)
 367                         return -ENOTCONN;
 368                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 369                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 370         } else {
 371                 __be32 addr = inet->inet_rcv_saddr;
 372                 if (!addr)
 373                         addr = inet->inet_saddr;
 374                 lsa->l2tp_conn_id = lsk->conn_id;
 375                 lsa->l2tp_addr.s_addr = addr;
 376         }
 377         *uaddr_len = sizeof(*lsa);
 378         return 0;
 379 }
 380
 381 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 382 {
 383         int rc;
 384
 385         /* Charge it to the socket, dropping if the queue is full. */
 386         rc = sock_queue_rcv_skb(sk, skb);
 387         if (rc < 0)
 388                 goto drop;
 389
 390         return 0;
 391
 392 drop:
 393         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 394         kfree_skb(skb);
 395         return 0;
 396 }
 397
 398 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 399  * control frames.
 400  */
 401 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 402 {
 403         struct sk_buff *skb;
 404         int rc;
 405         struct inet_sock *inet = inet_sk(sk);
 406         struct rtable *rt = NULL;
 407         struct flowi4 *fl4;
 408         int connected = 0;
 409         __be32 daddr;
 410
 411         lock_sock(sk);
 412
 413         rc = -ENOTCONN;
 414         if (sock_flag(sk, SOCK_DEAD))
 415                 goto out;
 416
 417         /* Get and verify the address. */
 418         if (msg->msg_name) {
 419                 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
 420                 rc = -EINVAL;
 421                 if (msg->msg_namelen < sizeof(*lip))
 422                         goto out;
 423
 424                 if (lip->l2tp_family != AF_INET) {
 425                         rc = -EAFNOSUPPORT;
 426                         if (lip->l2tp_family != AF_UNSPEC)
 427                                 goto out;
 428                 }
 429
 430                 daddr = lip->l2tp_addr.s_addr;
 431         } else {
 432                 rc = -EDESTADDRREQ;
 433                 if (sk->sk_state != TCP_ESTABLISHED)
 434                         goto out;
 435
 436                 daddr = inet->inet_daddr;
 437                 connected = 1;
 438         }
 439
 440         /* Allocate a socket buffer */
 441         rc = -ENOMEM;
 442         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 443                            4 + len, 0, GFP_KERNEL);
 444         if (!skb)
 445                 goto error;
 446
 447         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 448         skb_reserve(skb, 2 + NET_SKB_PAD);
 449         skb_reset_network_header(skb);
 450         skb_reserve(skb, sizeof(struct iphdr));
 451         skb_reset_transport_header(skb);
 452
 453         /* Insert 0 session_id */
 454         *((__be32 *) skb_put(skb, 4)) = 0;
 455
 456         /* Copy user data into skb */
 457         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 458         if (rc < 0) {
 459                 kfree_skb(skb);
 460                 goto error;
 461         }
 462
 463         fl4 = &inet->cork.fl.u.ip4;
 464         if (connected)
 465                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 466
 467         rcu_read_lock();
 468         if (rt == NULL) {
 469                 const struct ip_options_rcu *inet_opt;
 470
 471                 inet_opt = rcu_dereference(inet->inet_opt);
 472
 473                 /* Use correct destination address if we have options. */
 474                 if (inet_opt && inet_opt->opt.srr)
 475                         daddr = inet_opt->opt.faddr;
 476
 477                 /* If this fails, retransmit mechanism of transport layer will
 478                  * keep trying until route appears or the connection times
 479                  * itself out.
 480                  */
 481                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 482                                            daddr, inet->inet_saddr,
 483                                            inet->inet_dport, inet->inet_sport,
 484                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 485                                            sk->sk_bound_dev_if);
 486                 if (IS_ERR(rt))
 487                         goto no_route;
 488                 if (connected) {
 489                         sk_setup_caps(sk, &rt->dst);
 490                 } else {
 491                         skb_dst_set(skb, &rt->dst);
 492                         goto xmit;
 493                 }
 494         }
 495
 496         /* We dont need to clone dst here, it is guaranteed to not disappear.
 497          *  __dev_xmit_skb() might force a refcount if needed.
 498          */
 499         skb_dst_set_noref(skb, &rt->dst);
 500
 501 xmit:
 502         /* Queue the packet to IP for output */
 503         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 504         rcu_read_unlock();
 505
 506 error:
 507         if (rc >= 0)
 508                 rc = len;
 509
 510 out:
 511         release_sock(sk);
 512         return rc;
 513
 514 no_route:
 515         rcu_read_unlock();
 516         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 517         kfree_skb(skb);
 518         rc = -EHOSTUNREACH;
 519         goto out;
 520 }
 521
 522 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 523                            size_t len, int noblock, int flags, int *addr_len)
 524 {
 525         struct inet_sock *inet = inet_sk(sk);
 526         size_t copied = 0;
 527         int err = -EOPNOTSUPP;
 528         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 529         struct sk_buff *skb;
 530
 531         if (flags & MSG_OOB)
 532                 goto out;
 533
 534         skb = skb_recv_datagram(sk, flags, noblock, &err);
 535         if (!skb)
 536                 goto out;
 537
 538         copied = skb->len;
 539         if (len < copied) {
 540                 msg->msg_flags |= MSG_TRUNC;
 541                 copied = len;
 542         }
 543
 544         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 545         if (err)
 546                 goto done;
 547
 548         sock_recv_timestamp(msg, sk, skb);
 549
 550         /* Copy the address. */
 551         if (sin) {
 552                 sin->sin_family = AF_INET;
 553                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 554                 sin->sin_port = 0;
 555                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 556                 *addr_len = sizeof(*sin);
 557         }
 558         if (inet->cmsg_flags)
 559                 ip_cmsg_recv(msg, skb);
 560         if (flags & MSG_TRUNC)
 561                 copied = skb->len;
 562 done:
 563         skb_free_datagram(sk, skb);
 564 out:
 565         return err ? err : copied;
 566 }
 567
 568 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 569 {
 570         struct sk_buff *skb;
 571         int amount;
 572
 573         switch (cmd) {
 574         case SIOCOUTQ:
 575                 amount = sk_wmem_alloc_get(sk);
 576                 break;
 577         case SIOCINQ:
 578                 spin_lock_bh(&sk->sk_receive_queue.lock);
 579                 skb = skb_peek(&sk->sk_receive_queue);
 580                 amount = skb ? skb->len : 0;
 581                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 582                 break;
 583
 584         default:
 585                 return -ENOIOCTLCMD;
 586         }
 587
 588         return put_user(amount, (int __user *)arg);
 589 }
 590 EXPORT_SYMBOL(l2tp_ioctl);
 591
 592 static struct proto l2tp_ip_prot = {
 593         .name              = "L2TP/IP",
 594         .owner             = THIS_MODULE,
 595         .init              = l2tp_ip_open,
 596         .close             = l2tp_ip_close,
 597         .bind              = l2tp_ip_bind,
 598         .connect           = l2tp_ip_connect,
 599         .disconnect        = l2tp_ip_disconnect,
 600         .ioctl             = l2tp_ioctl,
 601         .destroy           = l2tp_ip_destroy_sock,
 602         .setsockopt        = ip_setsockopt,
 603         .getsockopt        = ip_getsockopt,
 604         .sendmsg           = l2tp_ip_sendmsg,
 605         .recvmsg           = l2tp_ip_recvmsg,
 606         .backlog_rcv       = l2tp_ip_backlog_recv,
 607         .hash              = inet_hash,
 608         .unhash            = inet_unhash,
 609         .obj_size          = sizeof(struct l2tp_ip_sock),
 610 #ifdef CONFIG_COMPAT
 611         .compat_setsockopt = compat_ip_setsockopt,
 612         .compat_getsockopt = compat_ip_getsockopt,
 613 #endif
 614 };
 615
 616 static const struct proto_ops l2tp_ip_ops = {
 617         .family            = PF_INET,
 618         .owner             = THIS_MODULE,
 619         .release           = inet_release,
 620         .bind              = inet_bind,
 621         .connect           = inet_dgram_connect,
 622         .socketpair        = sock_no_socketpair,
 623         .accept            = sock_no_accept,
 624         .getname           = l2tp_ip_getname,
 625         .poll              = datagram_poll,
 626         .ioctl             = inet_ioctl,
 627         .listen            = sock_no_listen,
 628         .shutdown          = inet_shutdown,
 629         .setsockopt        = sock_common_setsockopt,
 630         .getsockopt        = sock_common_getsockopt,
 631         .sendmsg           = inet_sendmsg,
 632         .recvmsg           = sock_common_recvmsg,
 633         .mmap              = sock_no_mmap,
 634         .sendpage          = sock_no_sendpage,
 635 #ifdef CONFIG_COMPAT
 636         .compat_setsockopt = compat_sock_common_setsockopt,
 637         .compat_getsockopt = compat_sock_common_getsockopt,
 638 #endif
 639 };
 640
 641 static struct inet_protosw l2tp_ip_protosw = {
 642         .type           = SOCK_DGRAM,
 643         .protocol       = IPPROTO_L2TP,
 644         .prot           = &l2tp_ip_prot,
 645         .ops            = &l2tp_ip_ops,
 646 };
 647
 648 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 649         .handler        = l2tp_ip_recv,
 650         .netns_ok       = 1,
 651 };
 652
 653 static int __init l2tp_ip_init(void)
 654 {
 655         int err;
 656
 657         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 658
 659         err = proto_register(&l2tp_ip_prot, 1);
 660         if (err != 0)
 661                 goto out;
 662
 663         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 664         if (err)
 665                 goto out1;
 666
 667         inet_register_protosw(&l2tp_ip_protosw);
 668         return 0;
 669
 670 out1:
 671         proto_unregister(&l2tp_ip_prot);
 672 out:
 673         return err;
 674 }
 675
 676 static void __exit l2tp_ip_exit(void)
 677 {
 678         inet_unregister_protosw(&l2tp_ip_protosw);
 679         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 680         proto_unregister(&l2tp_ip_prot);
 681 }
 682
 683 module_init(l2tp_ip_init);
 684 module_exit(l2tp_ip_exit);
 685
 686 MODULE_LICENSE("GPL");
 687 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 688 MODULE_DESCRIPTION("L2TP over IP");
 689 MODULE_VERSION("1.0");
 690
 691 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 692  * enums
 693  */
 694 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 695 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);