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 <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
  33 struct 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
  41 static DEFINE_RWLOCK(l2tp_ip_lock);
  42 static struct hlist_head l2tp_ip_table;
  43 static struct hlist_head l2tp_ip_bind_table;
  44
  45 static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
  46 {
  47         return (struct l2tp_ip_sock *)sk;
  48 }
  49
  50 static 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;
  70 found:
  71         return sk;
  72 }
  73
  74 static 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  */
 116 static 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
 167 pass_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
 199 discard_put:
 200         sock_put(sk);
 201
 202 discard:
 203         kfree_skb(skb);
 204         return 0;
 205 }
 206
 207 static 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
 219 static 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
 228 static 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
 238 static 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
 284 out:
 285         release_sock(sk);
 286
 287         return ret;
 288
 289 out_in_use:
 290         read_unlock_bh(&l2tp_ip_lock);
 291
 292         return ret;
 293 }
 294
 295 static 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
 326 static 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
 334 static 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
 360 static 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
 371 drop:
 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  */
 380 static 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
 480 xmit:
 481         /* Queue the packet to IP for output */
 482         rc = ip_queue_xmit(skb, &inet->cork.fl);
 483         rcu_read_unlock();
 484
 485 error:
 486         if (rc >= 0)
 487                 rc = len;
 488
 489 out:
 490         release_sock(sk);
 491         return rc;
 492
 493 no_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
 501 static 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;
 543 done:
 544         skb_free_datagram(sk, skb);
 545 out:
 546         return err ? err : copied;
 547 }
 548
 549 static 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
 573 static 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
 598 static 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
 606 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 607         .handler        = l2tp_ip_recv,
 608 };
 609
 610 static 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
 627 out1:
 628         proto_unregister(&l2tp_ip_prot);
 629 out:
 630         return err;
 631 }
 632
 633 static 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
 640 module_init(l2tp_ip_init);
 641 module_exit(l2tp_ip_exit);
 642
 643 MODULE_LICENSE("GPL");
 644 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 645 MODULE_DESCRIPTION("L2TP over IP");
 646 MODULE_VERSION("1.0");
 647
 648 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 649  * enums
 650  */
 651 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);