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 sock *sk;
  53
  54         sk_for_each_bound(sk, &l2tp_ip_bind_table) {
  55                 struct inet_sock *inet = inet_sk(sk);
  56                 struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
  57
  58                 if (l2tp == NULL)
  59                         continue;
  60
  61                 if ((l2tp->conn_id == tunnel_id) &&
  62                     net_eq(sock_net(sk), net) &&
  63                     !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
  64                     !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
  65                         goto found;
  66         }
  67
  68         sk = NULL;
  69 found:
  70         return sk;
  71 }
  72
  73 static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
  74 {
  75         struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
  76         if (sk)
  77                 sock_hold(sk);
  78
  79         return sk;
  80 }
  81
  82 /* When processing receive frames, there are two cases to
  83  * consider. Data frames consist of a non-zero session-id and an
  84  * optional cookie. Control frames consist of a regular L2TP header
  85  * preceded by 32-bits of zeros.
  86  *
  87  * L2TPv3 Session Header Over IP
  88  *
  89  *  0                   1                   2                   3
  90  *  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
  91  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  92  * |                           Session ID                          |
  93  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  94  * |               Cookie (optional, maximum 64 bits)...
  95  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  96  *                                                                 |
  97  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  98  *
  99  * L2TPv3 Control Message Header Over IP
 100  *
 101  *  0                   1                   2                   3
 102  *  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
 103  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 104  * |                      (32 bits of zeros)                       |
 105  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 106  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 107  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 108  * |                     Control Connection ID                     |
 109  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 110  * |               Ns              |               Nr              |
 111  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 112  *
 113  * All control frames are passed to userspace.
 114  */
 115 static int l2tp_ip_recv(struct sk_buff *skb)
 116 {
 117         struct net *net = dev_net(skb->dev);
 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         if (!pskb_may_pull(skb, 4))
 127                 goto discard;
 128
 129         /* Point to L2TP header */
 130         optr = ptr = skb->data;
 131         session_id = ntohl(*((__be32 *) ptr));
 132         ptr += 4;
 133
 134         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 135          * the session_id. If it is 0, the packet is a L2TP control
 136          * frame and the session_id value can be discarded.
 137          */
 138         if (session_id == 0) {
 139                 __skb_pull(skb, 4);
 140                 goto pass_up;
 141         }
 142
 143         /* Ok, this is a data packet. Lookup the session. */
 144         session = l2tp_session_find(net, NULL, session_id);
 145         if (session == NULL)
 146                 goto discard;
 147
 148         tunnel = session->tunnel;
 149         if (tunnel == NULL)
 150                 goto discard;
 151
 152         /* Trace packet contents, if enabled */
 153         if (tunnel->debug & L2TP_MSG_DATA) {
 154                 length = min(32u, skb->len);
 155                 if (!pskb_may_pull(skb, length))
 156                         goto discard;
 157
 158                 /* Point to L2TP header */
 159                 optr = ptr = skb->data;
 160                 ptr += 4;
 161                 pr_debug("%s: ip recv\n", tunnel->name);
 162                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 163         }
 164
 165         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
 166
 167         return 0;
 168
 169 pass_up:
 170         /* Get the tunnel_id from the L2TP header */
 171         if (!pskb_may_pull(skb, 12))
 172                 goto discard;
 173
 174         if ((skb->data[0] & 0xc0) != 0xc0)
 175                 goto discard;
 176
 177         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 178         tunnel = l2tp_tunnel_find(net, tunnel_id);
 179         if (tunnel != NULL)
 180                 sk = tunnel->sock;
 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, 0, tunnel_id);
 186                 read_unlock_bh(&l2tp_ip_lock);
 187         }
 188
 189         if (sk == NULL)
 190                 goto discard;
 191
 192         sock_hold(sk);
 193
 194         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 195                 goto discard_put;
 196
 197         nf_reset(skb);
 198
 199         return sk_receive_skb(sk, skb, 1);
 200
 201 discard_put:
 202         sock_put(sk);
 203
 204 discard:
 205         kfree_skb(skb);
 206         return 0;
 207 }
 208
 209 static int l2tp_ip_open(struct sock *sk)
 210 {
 211         /* Prevent autobind. We don't have ports. */
 212         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 213
 214         write_lock_bh(&l2tp_ip_lock);
 215         sk_add_node(sk, &l2tp_ip_table);
 216         write_unlock_bh(&l2tp_ip_lock);
 217
 218         return 0;
 219 }
 220
 221 static void l2tp_ip_close(struct sock *sk, long timeout)
 222 {
 223         write_lock_bh(&l2tp_ip_lock);
 224         hlist_del_init(&sk->sk_bind_node);
 225         sk_del_node_init(sk);
 226         write_unlock_bh(&l2tp_ip_lock);
 227         sk_common_release(sk);
 228 }
 229
 230 static void l2tp_ip_destroy_sock(struct sock *sk)
 231 {
 232         struct sk_buff *skb;
 233         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 234
 235         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 236                 kfree_skb(skb);
 237
 238         if (tunnel) {
 239                 l2tp_tunnel_closeall(tunnel);
 240                 sock_put(sk);
 241         }
 242
 243         sk_refcnt_debug_dec(sk);
 244 }
 245
 246 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 247 {
 248         struct inet_sock *inet = inet_sk(sk);
 249         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 250         struct net *net = sock_net(sk);
 251         int ret;
 252         int chk_addr_ret;
 253
 254         if (!sock_flag(sk, SOCK_ZAPPED))
 255                 return -EINVAL;
 256         if (addr_len < sizeof(struct sockaddr_l2tpip))
 257                 return -EINVAL;
 258         if (addr->l2tp_family != AF_INET)
 259                 return -EINVAL;
 260
 261         ret = -EADDRINUSE;
 262         read_lock_bh(&l2tp_ip_lock);
 263         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr,
 264                                   sk->sk_bound_dev_if, addr->l2tp_conn_id))
 265                 goto out_in_use;
 266
 267         read_unlock_bh(&l2tp_ip_lock);
 268
 269         lock_sock(sk);
 270         if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
 271                 goto out;
 272
 273         chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
 274         ret = -EADDRNOTAVAIL;
 275         if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
 276             chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 277                 goto out;
 278
 279         if (addr->l2tp_addr.s_addr)
 280                 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
 281         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 282                 inet->inet_saddr = 0;  /* Use device */
 283         sk_dst_reset(sk);
 284
 285         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 286
 287         write_lock_bh(&l2tp_ip_lock);
 288         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 289         sk_del_node_init(sk);
 290         write_unlock_bh(&l2tp_ip_lock);
 291         ret = 0;
 292         sock_reset_flag(sk, SOCK_ZAPPED);
 293
 294 out:
 295         release_sock(sk);
 296
 297         return ret;
 298
 299 out_in_use:
 300         read_unlock_bh(&l2tp_ip_lock);
 301
 302         return ret;
 303 }
 304
 305 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 306 {
 307         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 308         int rc;
 309
 310         if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
 311                 return -EINVAL;
 312
 313         if (addr_len < sizeof(*lsa))
 314                 return -EINVAL;
 315
 316         if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 317                 return -EINVAL;
 318
 319         rc = ip4_datagram_connect(sk, uaddr, addr_len);
 320         if (rc < 0)
 321                 return rc;
 322
 323         lock_sock(sk);
 324
 325         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 326
 327         write_lock_bh(&l2tp_ip_lock);
 328         hlist_del_init(&sk->sk_bind_node);
 329         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 330         write_unlock_bh(&l2tp_ip_lock);
 331
 332         release_sock(sk);
 333         return rc;
 334 }
 335
 336 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 337 {
 338         if (sock_flag(sk, SOCK_ZAPPED))
 339                 return 0;
 340
 341         return udp_disconnect(sk, flags);
 342 }
 343
 344 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 345                            int *uaddr_len, int peer)
 346 {
 347         struct sock *sk         = sock->sk;
 348         struct inet_sock *inet  = inet_sk(sk);
 349         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 350         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 351
 352         memset(lsa, 0, sizeof(*lsa));
 353         lsa->l2tp_family = AF_INET;
 354         if (peer) {
 355                 if (!inet->inet_dport)
 356                         return -ENOTCONN;
 357                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 358                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 359         } else {
 360                 __be32 addr = inet->inet_rcv_saddr;
 361                 if (!addr)
 362                         addr = inet->inet_saddr;
 363                 lsa->l2tp_conn_id = lsk->conn_id;
 364                 lsa->l2tp_addr.s_addr = addr;
 365         }
 366         *uaddr_len = sizeof(*lsa);
 367         return 0;
 368 }
 369
 370 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 371 {
 372         int rc;
 373
 374         /* Charge it to the socket, dropping if the queue is full. */
 375         rc = sock_queue_rcv_skb(sk, skb);
 376         if (rc < 0)
 377                 goto drop;
 378
 379         return 0;
 380
 381 drop:
 382         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 383         kfree_skb(skb);
 384         return -1;
 385 }
 386
 387 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 388  * control frames.
 389  */
 390 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 391 {
 392         struct sk_buff *skb;
 393         int rc;
 394         struct inet_sock *inet = inet_sk(sk);
 395         struct rtable *rt = NULL;
 396         struct flowi4 *fl4;
 397         int connected = 0;
 398         __be32 daddr;
 399
 400         lock_sock(sk);
 401
 402         rc = -ENOTCONN;
 403         if (sock_flag(sk, SOCK_DEAD))
 404                 goto out;
 405
 406         /* Get and verify the address. */
 407         if (msg->msg_name) {
 408                 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
 409                 rc = -EINVAL;
 410                 if (msg->msg_namelen < sizeof(*lip))
 411                         goto out;
 412
 413                 if (lip->l2tp_family != AF_INET) {
 414                         rc = -EAFNOSUPPORT;
 415                         if (lip->l2tp_family != AF_UNSPEC)
 416                                 goto out;
 417                 }
 418
 419                 daddr = lip->l2tp_addr.s_addr;
 420         } else {
 421                 rc = -EDESTADDRREQ;
 422                 if (sk->sk_state != TCP_ESTABLISHED)
 423                         goto out;
 424
 425                 daddr = inet->inet_daddr;
 426                 connected = 1;
 427         }
 428
 429         /* Allocate a socket buffer */
 430         rc = -ENOMEM;
 431         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 432                            4 + len, 0, GFP_KERNEL);
 433         if (!skb)
 434                 goto error;
 435
 436         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 437         skb_reserve(skb, 2 + NET_SKB_PAD);
 438         skb_reset_network_header(skb);
 439         skb_reserve(skb, sizeof(struct iphdr));
 440         skb_reset_transport_header(skb);
 441
 442         /* Insert 0 session_id */
 443         *((__be32 *) skb_put(skb, 4)) = 0;
 444
 445         /* Copy user data into skb */
 446         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 447         if (rc < 0) {
 448                 kfree_skb(skb);
 449                 goto error;
 450         }
 451
 452         fl4 = &inet->cork.fl.u.ip4;
 453         if (connected)
 454                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 455
 456         rcu_read_lock();
 457         if (rt == NULL) {
 458                 const struct ip_options_rcu *inet_opt;
 459
 460                 inet_opt = rcu_dereference(inet->inet_opt);
 461
 462                 /* Use correct destination address if we have options. */
 463                 if (inet_opt && inet_opt->opt.srr)
 464                         daddr = inet_opt->opt.faddr;
 465
 466                 /* If this fails, retransmit mechanism of transport layer will
 467                  * keep trying until route appears or the connection times
 468                  * itself out.
 469                  */
 470                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 471                                            daddr, inet->inet_saddr,
 472                                            inet->inet_dport, inet->inet_sport,
 473                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 474                                            sk->sk_bound_dev_if);
 475                 if (IS_ERR(rt))
 476                         goto no_route;
 477                 if (connected) {
 478                         sk_setup_caps(sk, &rt->dst);
 479                 } else {
 480                         skb_dst_set(skb, &rt->dst);
 481                         goto xmit;
 482                 }
 483         }
 484
 485         /* We dont need to clone dst here, it is guaranteed to not disappear.
 486          *  __dev_xmit_skb() might force a refcount if needed.
 487          */
 488         skb_dst_set_noref(skb, &rt->dst);
 489
 490 xmit:
 491         /* Queue the packet to IP for output */
 492         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 493         rcu_read_unlock();
 494
 495 error:
 496         if (rc >= 0)
 497                 rc = len;
 498
 499 out:
 500         release_sock(sk);
 501         return rc;
 502
 503 no_route:
 504         rcu_read_unlock();
 505         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 506         kfree_skb(skb);
 507         rc = -EHOSTUNREACH;
 508         goto out;
 509 }
 510
 511 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 512                            size_t len, int noblock, int flags, int *addr_len)
 513 {
 514         struct inet_sock *inet = inet_sk(sk);
 515         size_t copied = 0;
 516         int err = -EOPNOTSUPP;
 517         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 518         struct sk_buff *skb;
 519
 520         if (flags & MSG_OOB)
 521                 goto out;
 522
 523         skb = skb_recv_datagram(sk, flags, noblock, &err);
 524         if (!skb)
 525                 goto out;
 526
 527         copied = skb->len;
 528         if (len < copied) {
 529                 msg->msg_flags |= MSG_TRUNC;
 530                 copied = len;
 531         }
 532
 533         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 534         if (err)
 535                 goto done;
 536
 537         sock_recv_timestamp(msg, sk, skb);
 538
 539         /* Copy the address. */
 540         if (sin) {
 541                 sin->sin_family = AF_INET;
 542                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 543                 sin->sin_port = 0;
 544                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 545                 *addr_len = sizeof(*sin);
 546         }
 547         if (inet->cmsg_flags)
 548                 ip_cmsg_recv(msg, skb);
 549         if (flags & MSG_TRUNC)
 550                 copied = skb->len;
 551 done:
 552         skb_free_datagram(sk, skb);
 553 out:
 554         return err ? err : copied;
 555 }
 556
 557 static struct proto l2tp_ip_prot = {
 558         .name              = "L2TP/IP",
 559         .owner             = THIS_MODULE,
 560         .init              = l2tp_ip_open,
 561         .close             = l2tp_ip_close,
 562         .bind              = l2tp_ip_bind,
 563         .connect           = l2tp_ip_connect,
 564         .disconnect        = l2tp_ip_disconnect,
 565         .ioctl             = udp_ioctl,
 566         .destroy           = l2tp_ip_destroy_sock,
 567         .setsockopt        = ip_setsockopt,
 568         .getsockopt        = ip_getsockopt,
 569         .sendmsg           = l2tp_ip_sendmsg,
 570         .recvmsg           = l2tp_ip_recvmsg,
 571         .backlog_rcv       = l2tp_ip_backlog_recv,
 572         .hash              = inet_hash,
 573         .unhash            = inet_unhash,
 574         .obj_size          = sizeof(struct l2tp_ip_sock),
 575 #ifdef CONFIG_COMPAT
 576         .compat_setsockopt = compat_ip_setsockopt,
 577         .compat_getsockopt = compat_ip_getsockopt,
 578 #endif
 579 };
 580
 581 static const struct proto_ops l2tp_ip_ops = {
 582         .family            = PF_INET,
 583         .owner             = THIS_MODULE,
 584         .release           = inet_release,
 585         .bind              = inet_bind,
 586         .connect           = inet_dgram_connect,
 587         .socketpair        = sock_no_socketpair,
 588         .accept            = sock_no_accept,
 589         .getname           = l2tp_ip_getname,
 590         .poll              = datagram_poll,
 591         .ioctl             = inet_ioctl,
 592         .listen            = sock_no_listen,
 593         .shutdown          = inet_shutdown,
 594         .setsockopt        = sock_common_setsockopt,
 595         .getsockopt        = sock_common_getsockopt,
 596         .sendmsg           = inet_sendmsg,
 597         .recvmsg           = sock_common_recvmsg,
 598         .mmap              = sock_no_mmap,
 599         .sendpage          = sock_no_sendpage,
 600 #ifdef CONFIG_COMPAT
 601         .compat_setsockopt = compat_sock_common_setsockopt,
 602         .compat_getsockopt = compat_sock_common_getsockopt,
 603 #endif
 604 };
 605
 606 static struct inet_protosw l2tp_ip_protosw = {
 607         .type           = SOCK_DGRAM,
 608         .protocol       = IPPROTO_L2TP,
 609         .prot           = &l2tp_ip_prot,
 610         .ops            = &l2tp_ip_ops,
 611 };
 612
 613 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 614         .handler        = l2tp_ip_recv,
 615         .netns_ok       = 1,
 616 };
 617
 618 static int __init l2tp_ip_init(void)
 619 {
 620         int err;
 621
 622         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 623
 624         err = proto_register(&l2tp_ip_prot, 1);
 625         if (err != 0)
 626                 goto out;
 627
 628         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 629         if (err)
 630                 goto out1;
 631
 632         inet_register_protosw(&l2tp_ip_protosw);
 633         return 0;
 634
 635 out1:
 636         proto_unregister(&l2tp_ip_prot);
 637 out:
 638         return err;
 639 }
 640
 641 static void __exit l2tp_ip_exit(void)
 642 {
 643         inet_unregister_protosw(&l2tp_ip_protosw);
 644         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 645         proto_unregister(&l2tp_ip_prot);
 646 }
 647
 648 module_init(l2tp_ip_init);
 649 module_exit(l2tp_ip_exit);
 650
 651 MODULE_LICENSE("GPL");
 652 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 653 MODULE_DESCRIPTION("L2TP over IP");
 654 MODULE_VERSION("1.0");
 655
 656 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 657  * enums
 658  */
 659 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 660 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);