linux/net/l2tp/l2tp_ip.c
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   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 <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 <net/sock.h>
  22#include <net/ip.h>
  23#include <net/icmp.h>
  24#include <net/udp.h>
  25#include <net/inet_common.h>
  26#include <net/inet_hashtables.h>
  27#include <net/tcp_states.h>
  28#include <net/protocol.h>
  29#include <net/xfrm.h>
  30
  31#include "l2tp_core.h"
  32
  33struct l2tp_ip_sock {
  34        /* inet_sock has to be the first member of l2tp_ip_sock */
  35        struct inet_sock        inet;
  36
  37        u32                     conn_id;
  38        u32                     peer_conn_id;
  39};
  40
  41static DEFINE_RWLOCK(l2tp_ip_lock);
  42static struct hlist_head l2tp_ip_table;
  43static struct hlist_head l2tp_ip_bind_table;
  44
  45static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
  46{
  47        return (struct l2tp_ip_sock *)sk;
  48}
  49
  50static struct sock *__l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
  51{
  52        struct hlist_node *node;
  53        struct sock *sk;
  54
  55        sk_for_each_bound(sk, node, &l2tp_ip_bind_table) {
  56                struct inet_sock *inet = inet_sk(sk);
  57                struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
  58
  59                if (l2tp == NULL)
  60                        continue;
  61
  62                if ((l2tp->conn_id == tunnel_id) &&
  63                    net_eq(sock_net(sk), net) &&
  64                    !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
  65                    !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
  66                        goto found;
  67        }
  68
  69        sk = NULL;
  70found:
  71        return sk;
  72}
  73
  74static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
  75{
  76        struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
  77        if (sk)
  78                sock_hold(sk);
  79
  80        return sk;
  81}
  82
  83/* When processing receive frames, there are two cases to
  84 * consider. Data frames consist of a non-zero session-id and an
  85 * optional cookie. Control frames consist of a regular L2TP header
  86 * preceded by 32-bits of zeros.
  87 *
  88 * L2TPv3 Session Header Over IP
  89 *
  90 *  0                   1                   2                   3
  91 *  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
  92 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  93 * |                           Session ID                          |
  94 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  95 * |               Cookie (optional, maximum 64 bits)...
  96 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  97 *                                                                 |
  98 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  99 *
 100 * L2TPv3 Control Message 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 * |                      (32 bits of zeros)                       |
 106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 107 * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 109 * |                     Control Connection ID                     |
 110 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 111 * |               Ns              |               Nr              |
 112 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 113 *
 114 * All control frames are passed to userspace.
 115 */
 116static int l2tp_ip_recv(struct sk_buff *skb)
 117{
 118        struct sock *sk;
 119        u32 session_id;
 120        u32 tunnel_id;
 121        unsigned char *ptr, *optr;
 122        struct l2tp_session *session;
 123        struct l2tp_tunnel *tunnel = NULL;
 124        int length;
 125
 126        /* Point to L2TP header */
 127        optr = ptr = skb->data;
 128
 129        if (!pskb_may_pull(skb, 4))
 130                goto discard;
 131
 132        session_id = ntohl(*((__be32 *) ptr));
 133        ptr += 4;
 134
 135        /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 136         * the session_id. If it is 0, the packet is a L2TP control
 137         * frame and the session_id value can be discarded.
 138         */
 139        if (session_id == 0) {
 140                __skb_pull(skb, 4);
 141                goto pass_up;
 142        }
 143
 144        /* Ok, this is a data packet. Lookup the session. */
 145        session = l2tp_session_find(&init_net, NULL, session_id);
 146        if (session == NULL)
 147                goto discard;
 148
 149        tunnel = session->tunnel;
 150        if (tunnel == NULL)
 151                goto discard;
 152
 153        /* Trace packet contents, if enabled */
 154        if (tunnel->debug & L2TP_MSG_DATA) {
 155                length = min(32u, skb->len);
 156                if (!pskb_may_pull(skb, length))
 157                        goto discard;
 158
 159                pr_debug("%s: ip recv\n", tunnel->name);
 160                print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 161        }
 162
 163        l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
 164
 165        return 0;
 166
 167pass_up:
 168        /* Get the tunnel_id from the L2TP header */
 169        if (!pskb_may_pull(skb, 12))
 170                goto discard;
 171
 172        if ((skb->data[0] & 0xc0) != 0xc0)
 173                goto discard;
 174
 175        tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 176        tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
 177        if (tunnel != NULL)
 178                sk = tunnel->sock;
 179        else {
 180                struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
 181
 182                read_lock_bh(&l2tp_ip_lock);
 183                sk = __l2tp_ip_bind_lookup(&init_net, iph->daddr, 0, tunnel_id);
 184                read_unlock_bh(&l2tp_ip_lock);
 185        }
 186
 187        if (sk == NULL)
 188                goto discard;
 189
 190        sock_hold(sk);
 191
 192        if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 193                goto discard_put;
 194
 195        nf_reset(skb);
 196
 197        return sk_receive_skb(sk, skb, 1);
 198
 199discard_put:
 200        sock_put(sk);
 201
 202discard:
 203        kfree_skb(skb);
 204        return 0;
 205}
 206
 207static int l2tp_ip_open(struct sock *sk)
 208{
 209        /* Prevent autobind. We don't have ports. */
 210        inet_sk(sk)->inet_num = IPPROTO_L2TP;
 211
 212        write_lock_bh(&l2tp_ip_lock);
 213        sk_add_node(sk, &l2tp_ip_table);
 214        write_unlock_bh(&l2tp_ip_lock);
 215
 216        return 0;
 217}
 218
 219static void l2tp_ip_close(struct sock *sk, long timeout)
 220{
 221        write_lock_bh(&l2tp_ip_lock);
 222        hlist_del_init(&sk->sk_bind_node);
 223        sk_del_node_init(sk);
 224        write_unlock_bh(&l2tp_ip_lock);
 225        sk_common_release(sk);
 226}
 227
 228static void l2tp_ip_destroy_sock(struct sock *sk)
 229{
 230        struct sk_buff *skb;
 231
 232        while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 233                kfree_skb(skb);
 234
 235        sk_refcnt_debug_dec(sk);
 236}
 237
 238static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 239{
 240        struct inet_sock *inet = inet_sk(sk);
 241        struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 242        int ret;
 243        int chk_addr_ret;
 244
 245        if (!sock_flag(sk, SOCK_ZAPPED))
 246                return -EINVAL;
 247        if (addr_len < sizeof(struct sockaddr_l2tpip))
 248                return -EINVAL;
 249        if (addr->l2tp_family != AF_INET)
 250                return -EINVAL;
 251
 252        ret = -EADDRINUSE;
 253        read_lock_bh(&l2tp_ip_lock);
 254        if (__l2tp_ip_bind_lookup(&init_net, addr->l2tp_addr.s_addr, sk->sk_bound_dev_if, addr->l2tp_conn_id))
 255                goto out_in_use;
 256
 257        read_unlock_bh(&l2tp_ip_lock);
 258
 259        lock_sock(sk);
 260        if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
 261                goto out;
 262
 263        chk_addr_ret = inet_addr_type(&init_net, addr->l2tp_addr.s_addr);
 264        ret = -EADDRNOTAVAIL;
 265        if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
 266            chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 267                goto out;
 268
 269        if (addr->l2tp_addr.s_addr)
 270                inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
 271        if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 272                inet->inet_saddr = 0;  /* Use device */
 273        sk_dst_reset(sk);
 274
 275        l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 276
 277        write_lock_bh(&l2tp_ip_lock);
 278        sk_add_bind_node(sk, &l2tp_ip_bind_table);
 279        sk_del_node_init(sk);
 280        write_unlock_bh(&l2tp_ip_lock);
 281        ret = 0;
 282        sock_reset_flag(sk, SOCK_ZAPPED);
 283
 284out:
 285        release_sock(sk);
 286
 287        return ret;
 288
 289out_in_use:
 290        read_unlock_bh(&l2tp_ip_lock);
 291
 292        return ret;
 293}
 294
 295static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 296{
 297        struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 298        int rc;
 299
 300        if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
 301                return -EINVAL;
 302
 303        if (addr_len < sizeof(*lsa))
 304                return -EINVAL;
 305
 306        if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 307                return -EINVAL;
 308
 309        rc = ip4_datagram_connect(sk, uaddr, addr_len);
 310        if (rc < 0)
 311                return rc;
 312
 313        lock_sock(sk);
 314
 315        l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 316
 317        write_lock_bh(&l2tp_ip_lock);
 318        hlist_del_init(&sk->sk_bind_node);
 319        sk_add_bind_node(sk, &l2tp_ip_bind_table);
 320        write_unlock_bh(&l2tp_ip_lock);
 321
 322        release_sock(sk);
 323        return rc;
 324}
 325
 326static int l2tp_ip_disconnect(struct sock *sk, int flags)
 327{
 328        if (sock_flag(sk, SOCK_ZAPPED))
 329                return 0;
 330
 331        return udp_disconnect(sk, flags);
 332}
 333
 334static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 335                           int *uaddr_len, int peer)
 336{
 337        struct sock *sk         = sock->sk;
 338        struct inet_sock *inet  = inet_sk(sk);
 339        struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 340        struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 341
 342        memset(lsa, 0, sizeof(*lsa));
 343        lsa->l2tp_family = AF_INET;
 344        if (peer) {
 345                if (!inet->inet_dport)
 346                        return -ENOTCONN;
 347                lsa->l2tp_conn_id = lsk->peer_conn_id;
 348                lsa->l2tp_addr.s_addr = inet->inet_daddr;
 349        } else {
 350                __be32 addr = inet->inet_rcv_saddr;
 351                if (!addr)
 352                        addr = inet->inet_saddr;
 353                lsa->l2tp_conn_id = lsk->conn_id;
 354                lsa->l2tp_addr.s_addr = addr;
 355        }
 356        *uaddr_len = sizeof(*lsa);
 357        return 0;
 358}
 359
 360static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 361{
 362        int rc;
 363
 364        /* Charge it to the socket, dropping if the queue is full. */
 365        rc = sock_queue_rcv_skb(sk, skb);
 366        if (rc < 0)
 367                goto drop;
 368
 369        return 0;
 370
 371drop:
 372        IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
 373        kfree_skb(skb);
 374        return -1;
 375}
 376
 377/* Userspace will call sendmsg() on the tunnel socket to send L2TP
 378 * control frames.
 379 */
 380static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len)
 381{
 382        struct sk_buff *skb;
 383        int rc;
 384        struct inet_sock *inet = inet_sk(sk);
 385        struct rtable *rt = NULL;
 386        struct flowi4 *fl4;
 387        int connected = 0;
 388        __be32 daddr;
 389
 390        lock_sock(sk);
 391
 392        rc = -ENOTCONN;
 393        if (sock_flag(sk, SOCK_DEAD))
 394                goto out;
 395
 396        /* Get and verify the address. */
 397        if (msg->msg_name) {
 398                struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name;
 399                rc = -EINVAL;
 400                if (msg->msg_namelen < sizeof(*lip))
 401                        goto out;
 402
 403                if (lip->l2tp_family != AF_INET) {
 404                        rc = -EAFNOSUPPORT;
 405                        if (lip->l2tp_family != AF_UNSPEC)
 406                                goto out;
 407                }
 408
 409                daddr = lip->l2tp_addr.s_addr;
 410        } else {
 411                rc = -EDESTADDRREQ;
 412                if (sk->sk_state != TCP_ESTABLISHED)
 413                        goto out;
 414
 415                daddr = inet->inet_daddr;
 416                connected = 1;
 417        }
 418
 419        /* Allocate a socket buffer */
 420        rc = -ENOMEM;
 421        skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 422                           4 + len, 0, GFP_KERNEL);
 423        if (!skb)
 424                goto error;
 425
 426        /* Reserve space for headers, putting IP header on 4-byte boundary. */
 427        skb_reserve(skb, 2 + NET_SKB_PAD);
 428        skb_reset_network_header(skb);
 429        skb_reserve(skb, sizeof(struct iphdr));
 430        skb_reset_transport_header(skb);
 431
 432        /* Insert 0 session_id */
 433        *((__be32 *) skb_put(skb, 4)) = 0;
 434
 435        /* Copy user data into skb */
 436        rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
 437        if (rc < 0) {
 438                kfree_skb(skb);
 439                goto error;
 440        }
 441
 442        fl4 = &inet->cork.fl.u.ip4;
 443        if (connected)
 444                rt = (struct rtable *) __sk_dst_check(sk, 0);
 445
 446        rcu_read_lock();
 447        if (rt == NULL) {
 448                const struct ip_options_rcu *inet_opt;
 449
 450                inet_opt = rcu_dereference(inet->inet_opt);
 451
 452                /* Use correct destination address if we have options. */
 453                if (inet_opt && inet_opt->opt.srr)
 454                        daddr = inet_opt->opt.faddr;
 455
 456                /* If this fails, retransmit mechanism of transport layer will
 457                 * keep trying until route appears or the connection times
 458                 * itself out.
 459                 */
 460                rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 461                                           daddr, inet->inet_saddr,
 462                                           inet->inet_dport, inet->inet_sport,
 463                                           sk->sk_protocol, RT_CONN_FLAGS(sk),
 464                                           sk->sk_bound_dev_if);
 465                if (IS_ERR(rt))
 466                        goto no_route;
 467                if (connected) {
 468                        sk_setup_caps(sk, &rt->dst);
 469                } else {
 470                        skb_dst_set(skb, &rt->dst);
 471                        goto xmit;
 472                }
 473        }
 474
 475        /* We dont need to clone dst here, it is guaranteed to not disappear.
 476         *  __dev_xmit_skb() might force a refcount if needed.
 477         */
 478        skb_dst_set_noref(skb, &rt->dst);
 479
 480xmit:
 481        /* Queue the packet to IP for output */
 482        rc = ip_queue_xmit(skb, &inet->cork.fl);
 483        rcu_read_unlock();
 484
 485error:
 486        if (rc >= 0)
 487                rc = len;
 488
 489out:
 490        release_sock(sk);
 491        return rc;
 492
 493no_route:
 494        rcu_read_unlock();
 495        IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 496        kfree_skb(skb);
 497        rc = -EHOSTUNREACH;
 498        goto out;
 499}
 500
 501static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 502                           size_t len, int noblock, int flags, int *addr_len)
 503{
 504        struct inet_sock *inet = inet_sk(sk);
 505        size_t copied = 0;
 506        int err = -EOPNOTSUPP;
 507        struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
 508        struct sk_buff *skb;
 509
 510        if (flags & MSG_OOB)
 511                goto out;
 512
 513        if (addr_len)
 514                *addr_len = sizeof(*sin);
 515
 516        skb = skb_recv_datagram(sk, flags, noblock, &err);
 517        if (!skb)
 518                goto out;
 519
 520        copied = skb->len;
 521        if (len < copied) {
 522                msg->msg_flags |= MSG_TRUNC;
 523                copied = len;
 524        }
 525
 526        err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 527        if (err)
 528                goto done;
 529
 530        sock_recv_timestamp(msg, sk, skb);
 531
 532        /* Copy the address. */
 533        if (sin) {
 534                sin->sin_family = AF_INET;
 535                sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 536                sin->sin_port = 0;
 537                memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 538        }
 539        if (inet->cmsg_flags)
 540                ip_cmsg_recv(msg, skb);
 541        if (flags & MSG_TRUNC)
 542                copied = skb->len;
 543done:
 544        skb_free_datagram(sk, skb);
 545out:
 546        return err ? err : copied;
 547}
 548
 549static struct proto l2tp_ip_prot = {
 550        .name              = "L2TP/IP",
 551        .owner             = THIS_MODULE,
 552        .init              = l2tp_ip_open,
 553        .close             = l2tp_ip_close,
 554        .bind              = l2tp_ip_bind,
 555        .connect           = l2tp_ip_connect,
 556        .disconnect        = l2tp_ip_disconnect,
 557        .ioctl             = udp_ioctl,
 558        .destroy           = l2tp_ip_destroy_sock,
 559        .setsockopt        = ip_setsockopt,
 560        .getsockopt        = ip_getsockopt,
 561        .sendmsg           = l2tp_ip_sendmsg,
 562        .recvmsg           = l2tp_ip_recvmsg,
 563        .backlog_rcv       = l2tp_ip_backlog_recv,
 564        .hash              = inet_hash,
 565        .unhash            = inet_unhash,
 566        .obj_size          = sizeof(struct l2tp_ip_sock),
 567#ifdef CONFIG_COMPAT
 568        .compat_setsockopt = compat_ip_setsockopt,
 569        .compat_getsockopt = compat_ip_getsockopt,
 570#endif
 571};
 572
 573static const struct proto_ops l2tp_ip_ops = {
 574        .family            = PF_INET,
 575        .owner             = THIS_MODULE,
 576        .release           = inet_release,
 577        .bind              = inet_bind,
 578        .connect           = inet_dgram_connect,
 579        .socketpair        = sock_no_socketpair,
 580        .accept            = sock_no_accept,
 581        .getname           = l2tp_ip_getname,
 582        .poll              = datagram_poll,
 583        .ioctl             = inet_ioctl,
 584        .listen            = sock_no_listen,
 585        .shutdown          = inet_shutdown,
 586        .setsockopt        = sock_common_setsockopt,
 587        .getsockopt        = sock_common_getsockopt,
 588        .sendmsg           = inet_sendmsg,
 589        .recvmsg           = sock_common_recvmsg,
 590        .mmap              = sock_no_mmap,
 591        .sendpage          = sock_no_sendpage,
 592#ifdef CONFIG_COMPAT
 593        .compat_setsockopt = compat_sock_common_setsockopt,
 594        .compat_getsockopt = compat_sock_common_getsockopt,
 595#endif
 596};
 597
 598static struct inet_protosw l2tp_ip_protosw = {
 599        .type           = SOCK_DGRAM,
 600        .protocol       = IPPROTO_L2TP,
 601        .prot           = &l2tp_ip_prot,
 602        .ops            = &l2tp_ip_ops,
 603        .no_check       = 0,
 604};
 605
 606static struct net_protocol l2tp_ip_protocol __read_mostly = {
 607        .handler        = l2tp_ip_recv,
 608};
 609
 610static int __init l2tp_ip_init(void)
 611{
 612        int err;
 613
 614        pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 615
 616        err = proto_register(&l2tp_ip_prot, 1);
 617        if (err != 0)
 618                goto out;
 619
 620        err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 621        if (err)
 622                goto out1;
 623
 624        inet_register_protosw(&l2tp_ip_protosw);
 625        return 0;
 626
 627out1:
 628        proto_unregister(&l2tp_ip_prot);
 629out:
 630        return err;
 631}
 632
 633static void __exit l2tp_ip_exit(void)
 634{
 635        inet_unregister_protosw(&l2tp_ip_protosw);
 636        inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 637        proto_unregister(&l2tp_ip_prot);
 638}
 639
 640module_init(l2tp_ip_init);
 641module_exit(l2tp_ip_exit);
 642
 643MODULE_LICENSE("GPL");
 644MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 645MODULE_DESCRIPTION("L2TP over IP");
 646MODULE_VERSION("1.0");
 647
 648/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 649 * enums
 650 */
 651MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 652
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