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 #include <linux/icmp.h>
  13 #include <linux/module.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/random.h>
  16 #include <linux/socket.h>
  17 #include <linux/l2tp.h>
  18 #include <linux/in.h>
  19 #include <net/sock.h>
  20 #include <net/ip.h>
  21 #include <net/icmp.h>
  22 #include <net/udp.h>
  23 #include <net/inet_common.h>
  24 #include <net/inet_hashtables.h>
  25 #include <net/tcp_states.h>
  26 #include <net/protocol.h>
  27 #include <net/xfrm.h>
  28
  29 #include "l2tp_core.h"
  30
  31 struct l2tp_ip_sock {
  32         /* inet_sock has to be the first member of l2tp_ip_sock */
  33         struct inet_sock        inet;
  34
  35         __u32                   conn_id;
  36         __u32                   peer_conn_id;
  37
  38         __u64                   tx_packets;
  39         __u64                   tx_bytes;
  40         __u64                   tx_errors;
  41         __u64                   rx_packets;
  42         __u64                   rx_bytes;
  43         __u64                   rx_errors;
  44 };
  45
  46 static DEFINE_RWLOCK(l2tp_ip_lock);
  47 static struct hlist_head l2tp_ip_table;
  48 static struct hlist_head l2tp_ip_bind_table;
  49
  50 static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
  51 {
  52         return (struct l2tp_ip_sock *)sk;
  53 }
  54
  55 static struct sock *__l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
  56 {
  57         struct hlist_node *node;
  58         struct sock *sk;
  59
  60         sk_for_each_bound(sk, node, &l2tp_ip_bind_table) {
  61                 struct inet_sock *inet = inet_sk(sk);
  62                 struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
  63
  64                 if (l2tp == NULL)
  65                         continue;
  66
  67                 if ((l2tp->conn_id == tunnel_id) &&
  68                     net_eq(sock_net(sk), net) &&
  69                     !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
  70                     !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
  71                         goto found;
  72         }
  73
  74         sk = NULL;
  75 found:
  76         return sk;
  77 }
  78
  79 static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
  80 {
  81         struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
  82         if (sk)
  83                 sock_hold(sk);
  84
  85         return sk;
  86 }
  87
  88 /* When processing receive frames, there are two cases to
  89  * consider. Data frames consist of a non-zero session-id and an
  90  * optional cookie. Control frames consist of a regular L2TP header
  91  * preceded by 32-bits of zeros.
  92  *
  93  * L2TPv3 Session Header Over IP
  94  *
  95  *  0                   1                   2                   3
  96  *  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
  97  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  98  * |                           Session ID                          |
  99  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 100  * |               Cookie (optional, maximum 64 bits)...
 101  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 102  *                                                                 |
 103  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 104  *
 105  * L2TPv3 Control Message Header Over IP
 106  *
 107  *  0                   1                   2                   3
 108  *  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
 109  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 110  * |                      (32 bits of zeros)                       |
 111  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 112  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 113  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 114  * |                     Control Connection ID                     |
 115  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 116  * |               Ns              |               Nr              |
 117  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 118  *
 119  * All control frames are passed to userspace.
 120  */
 121 static int l2tp_ip_recv(struct sk_buff *skb)
 122 {
 123         struct sock *sk;
 124         u32 session_id;
 125         u32 tunnel_id;
 126         unsigned char *ptr, *optr;
 127         struct l2tp_session *session;
 128         struct l2tp_tunnel *tunnel = NULL;
 129         int length;
 130         int offset;
 131
 132         /* Point to L2TP header */
 133         optr = ptr = skb->data;
 134
 135         if (!pskb_may_pull(skb, 4))
 136                 goto discard;
 137
 138         session_id = ntohl(*((__be32 *) ptr));
 139         ptr += 4;
 140
 141         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 142          * the session_id. If it is 0, the packet is a L2TP control
 143          * frame and the session_id value can be discarded.
 144          */
 145         if (session_id == 0) {
 146                 __skb_pull(skb, 4);
 147                 goto pass_up;
 148         }
 149
 150         /* Ok, this is a data packet. Lookup the session. */
 151         session = l2tp_session_find(&init_net, NULL, session_id);
 152         if (session == NULL)
 153                 goto discard;
 154
 155         tunnel = session->tunnel;
 156         if (tunnel == NULL)
 157                 goto discard;
 158
 159         /* Trace packet contents, if enabled */
 160         if (tunnel->debug & L2TP_MSG_DATA) {
 161                 length = min(32u, skb->len);
 162                 if (!pskb_may_pull(skb, length))
 163                         goto discard;
 164
 165                 printk(KERN_DEBUG "%s: ip recv: ", tunnel->name);
 166
 167                 offset = 0;
 168                 do {
 169                         printk(" %02X", ptr[offset]);
 170                 } while (++offset < length);
 171
 172                 printk("\n");
 173         }
 174
 175         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
 176
 177         return 0;
 178
 179 pass_up:
 180         /* Get the tunnel_id from the L2TP header */
 181         if (!pskb_may_pull(skb, 12))
 182                 goto discard;
 183
 184         if ((skb->data[0] & 0xc0) != 0xc0)
 185                 goto discard;
 186
 187         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 188         tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
 189         if (tunnel != NULL)
 190                 sk = tunnel->sock;
 191         else {
 192                 struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
 193
 194                 read_lock_bh(&l2tp_ip_lock);
 195                 sk = __l2tp_ip_bind_lookup(&init_net, iph->daddr, 0, tunnel_id);
 196                 read_unlock_bh(&l2tp_ip_lock);
 197         }
 198
 199         if (sk == NULL)
 200                 goto discard;
 201
 202         sock_hold(sk);
 203
 204         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 205                 goto discard_put;
 206
 207         nf_reset(skb);
 208
 209         return sk_receive_skb(sk, skb, 1);
 210
 211 discard_put:
 212         sock_put(sk);
 213
 214 discard:
 215         kfree_skb(skb);
 216         return 0;
 217 }
 218
 219 static int l2tp_ip_open(struct sock *sk)
 220 {
 221         /* Prevent autobind. We don't have ports. */
 222         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 223
 224         write_lock_bh(&l2tp_ip_lock);
 225         sk_add_node(sk, &l2tp_ip_table);
 226         write_unlock_bh(&l2tp_ip_lock);
 227
 228         return 0;
 229 }
 230
 231 static void l2tp_ip_close(struct sock *sk, long timeout)
 232 {
 233         write_lock_bh(&l2tp_ip_lock);
 234         hlist_del_init(&sk->sk_bind_node);
 235         hlist_del_init(&sk->sk_node);
 236         write_unlock_bh(&l2tp_ip_lock);
 237         sk_common_release(sk);
 238 }
 239
 240 static void l2tp_ip_destroy_sock(struct sock *sk)
 241 {
 242         struct sk_buff *skb;
 243
 244         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 245                 kfree_skb(skb);
 246
 247         sk_refcnt_debug_dec(sk);
 248 }
 249
 250 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 251 {
 252         struct inet_sock *inet = inet_sk(sk);
 253         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 254         int ret = -EINVAL;
 255         int chk_addr_ret;
 256
 257         ret = -EADDRINUSE;
 258         read_lock_bh(&l2tp_ip_lock);
 259         if (__l2tp_ip_bind_lookup(&init_net, addr->l2tp_addr.s_addr, sk->sk_bound_dev_if, addr->l2tp_conn_id))
 260                 goto out_in_use;
 261
 262         read_unlock_bh(&l2tp_ip_lock);
 263
 264         lock_sock(sk);
 265         if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
 266                 goto out;
 267
 268         chk_addr_ret = inet_addr_type(&init_net, addr->l2tp_addr.s_addr);
 269         ret = -EADDRNOTAVAIL;
 270         if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
 271             chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 272                 goto out;
 273
 274         inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
 275         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 276                 inet->inet_saddr = 0;  /* Use device */
 277         sk_dst_reset(sk);
 278
 279         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 280
 281         write_lock_bh(&l2tp_ip_lock);
 282         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 283         sk_del_node_init(sk);
 284         write_unlock_bh(&l2tp_ip_lock);
 285         ret = 0;
 286 out:
 287         release_sock(sk);
 288
 289         return ret;
 290
 291 out_in_use:
 292         read_unlock_bh(&l2tp_ip_lock);
 293
 294         return ret;
 295 }
 296
 297 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 298 {
 299         int rc;
 300         struct inet_sock *inet = inet_sk(sk);
 301         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 302         struct rtable *rt;
 303         __be32 saddr;
 304         int oif;
 305
 306         rc = -EINVAL;
 307         if (addr_len < sizeof(*lsa))
 308                 goto out;
 309
 310         rc = -EAFNOSUPPORT;
 311         if (lsa->l2tp_family != AF_INET)
 312                 goto out;
 313
 314         sk_dst_reset(sk);
 315
 316         oif = sk->sk_bound_dev_if;
 317         saddr = inet->inet_saddr;
 318
 319         rc = -EINVAL;
 320         if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 321                 goto out;
 322
 323         rt = ip_route_connect(lsa->l2tp_addr.s_addr, saddr,
 324                               RT_CONN_FLAGS(sk), oif,
 325                               IPPROTO_L2TP,
 326                               0, 0, sk, true);
 327         if (IS_ERR(rt)) {
 328                 rc = PTR_ERR(rt);
 329                 if (rc == -ENETUNREACH)
 330                         IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES);
 331                 goto out;
 332         }
 333
 334         rc = -ENETUNREACH;
 335         if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
 336                 ip_rt_put(rt);
 337                 goto out;
 338         }
 339
 340         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 341
 342         if (!inet->inet_saddr)
 343                 inet->inet_saddr = rt->rt_src;
 344         if (!inet->inet_rcv_saddr)
 345                 inet->inet_rcv_saddr = rt->rt_src;
 346         inet->inet_daddr = rt->rt_dst;
 347         sk->sk_state = TCP_ESTABLISHED;
 348         inet->inet_id = jiffies;
 349
 350         sk_dst_set(sk, &rt->dst);
 351
 352         write_lock_bh(&l2tp_ip_lock);
 353         hlist_del_init(&sk->sk_bind_node);
 354         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 355         write_unlock_bh(&l2tp_ip_lock);
 356
 357         rc = 0;
 358 out:
 359         return rc;
 360 }
 361
 362 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 363                            int *uaddr_len, int peer)
 364 {
 365         struct sock *sk         = sock->sk;
 366         struct inet_sock *inet  = inet_sk(sk);
 367         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 368         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 369
 370         memset(lsa, 0, sizeof(*lsa));
 371         lsa->l2tp_family = AF_INET;
 372         if (peer) {
 373                 if (!inet->inet_dport)
 374                         return -ENOTCONN;
 375                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 376                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 377         } else {
 378                 __be32 addr = inet->inet_rcv_saddr;
 379                 if (!addr)
 380                         addr = inet->inet_saddr;
 381                 lsa->l2tp_conn_id = lsk->conn_id;
 382                 lsa->l2tp_addr.s_addr = addr;
 383         }
 384         *uaddr_len = sizeof(*lsa);
 385         return 0;
 386 }
 387
 388 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 389 {
 390         int rc;
 391
 392         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 393                 goto drop;
 394
 395         nf_reset(skb);
 396
 397         /* Charge it to the socket, dropping if the queue is full. */
 398         rc = sock_queue_rcv_skb(sk, skb);
 399         if (rc < 0)
 400                 goto drop;
 401
 402         return 0;
 403
 404 drop:
 405         IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
 406         kfree_skb(skb);
 407         return -1;
 408 }
 409
 410 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 411  * control frames.
 412  */
 413 static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len)
 414 {
 415         struct sk_buff *skb;
 416         int rc;
 417         struct l2tp_ip_sock *lsa = l2tp_ip_sk(sk);
 418         struct inet_sock *inet = inet_sk(sk);
 419         struct ip_options *opt = inet->opt;
 420         struct rtable *rt = NULL;
 421         int connected = 0;
 422         __be32 daddr;
 423
 424         if (sock_flag(sk, SOCK_DEAD))
 425                 return -ENOTCONN;
 426
 427         /* Get and verify the address. */
 428         if (msg->msg_name) {
 429                 struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name;
 430                 if (msg->msg_namelen < sizeof(*lip))
 431                         return -EINVAL;
 432
 433                 if (lip->l2tp_family != AF_INET) {
 434                         if (lip->l2tp_family != AF_UNSPEC)
 435                                 return -EAFNOSUPPORT;
 436                 }
 437
 438                 daddr = lip->l2tp_addr.s_addr;
 439         } else {
 440                 if (sk->sk_state != TCP_ESTABLISHED)
 441                         return -EDESTADDRREQ;
 442
 443                 daddr = inet->inet_daddr;
 444                 connected = 1;
 445         }
 446
 447         /* Allocate a socket buffer */
 448         rc = -ENOMEM;
 449         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 450                            4 + len, 0, GFP_KERNEL);
 451         if (!skb)
 452                 goto error;
 453
 454         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 455         skb_reserve(skb, 2 + NET_SKB_PAD);
 456         skb_reset_network_header(skb);
 457         skb_reserve(skb, sizeof(struct iphdr));
 458         skb_reset_transport_header(skb);
 459
 460         /* Insert 0 session_id */
 461         *((__be32 *) skb_put(skb, 4)) = 0;
 462
 463         /* Copy user data into skb */
 464         rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
 465         if (rc < 0) {
 466                 kfree_skb(skb);
 467                 goto error;
 468         }
 469
 470         if (connected)
 471                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 472
 473         if (rt == NULL) {
 474                 /* Use correct destination address if we have options. */
 475                 if (opt && opt->srr)
 476                         daddr = opt->faddr;
 477
 478                 /* If this fails, retransmit mechanism of transport layer will
 479                  * keep trying until route appears or the connection times
 480                  * itself out.
 481                  */
 482                 rt = ip_route_output_ports(sock_net(sk), sk,
 483                                            daddr, inet->inet_saddr,
 484                                            inet->inet_dport, inet->inet_sport,
 485                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 486                                            sk->sk_bound_dev_if);
 487                 if (IS_ERR(rt))
 488                         goto no_route;
 489                 sk_setup_caps(sk, &rt->dst);
 490         }
 491         skb_dst_set(skb, dst_clone(&rt->dst));
 492
 493         /* Queue the packet to IP for output */
 494         rc = ip_queue_xmit(skb);
 495
 496 error:
 497         /* Update stats */
 498         if (rc >= 0) {
 499                 lsa->tx_packets++;
 500                 lsa->tx_bytes += len;
 501                 rc = len;
 502         } else {
 503                 lsa->tx_errors++;
 504         }
 505
 506         return rc;
 507
 508 no_route:
 509         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 510         kfree_skb(skb);
 511         return -EHOSTUNREACH;
 512 }
 513
 514 static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 515                            size_t len, int noblock, int flags, int *addr_len)
 516 {
 517         struct inet_sock *inet = inet_sk(sk);
 518         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 519         size_t copied = 0;
 520         int err = -EOPNOTSUPP;
 521         struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
 522         struct sk_buff *skb;
 523
 524         if (flags & MSG_OOB)
 525                 goto out;
 526
 527         if (addr_len)
 528                 *addr_len = sizeof(*sin);
 529
 530         skb = skb_recv_datagram(sk, flags, noblock, &err);
 531         if (!skb)
 532                 goto out;
 533
 534         copied = skb->len;
 535         if (len < copied) {
 536                 msg->msg_flags |= MSG_TRUNC;
 537                 copied = len;
 538         }
 539
 540         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 541         if (err)
 542                 goto done;
 543
 544         sock_recv_timestamp(msg, sk, skb);
 545
 546         /* Copy the address. */
 547         if (sin) {
 548                 sin->sin_family = AF_INET;
 549                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 550                 sin->sin_port = 0;
 551                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 552         }
 553         if (inet->cmsg_flags)
 554                 ip_cmsg_recv(msg, skb);
 555         if (flags & MSG_TRUNC)
 556                 copied = skb->len;
 557 done:
 558         skb_free_datagram(sk, skb);
 559 out:
 560         if (err) {
 561                 lsk->rx_errors++;
 562                 return err;
 563         }
 564
 565         lsk->rx_packets++;
 566         lsk->rx_bytes += copied;
 567
 568         return copied;
 569 }
 570
 571 static struct proto l2tp_ip_prot = {
 572         .name              = "L2TP/IP",
 573         .owner             = THIS_MODULE,
 574         .init              = l2tp_ip_open,
 575         .close             = l2tp_ip_close,
 576         .bind              = l2tp_ip_bind,
 577         .connect           = l2tp_ip_connect,
 578         .disconnect        = udp_disconnect,
 579         .ioctl             = udp_ioctl,
 580         .destroy           = l2tp_ip_destroy_sock,
 581         .setsockopt        = ip_setsockopt,
 582         .getsockopt        = ip_getsockopt,
 583         .sendmsg           = l2tp_ip_sendmsg,
 584         .recvmsg           = l2tp_ip_recvmsg,
 585         .backlog_rcv       = l2tp_ip_backlog_recv,
 586         .hash              = inet_hash,
 587         .unhash            = inet_unhash,
 588         .obj_size          = sizeof(struct l2tp_ip_sock),
 589 #ifdef CONFIG_COMPAT
 590         .compat_setsockopt = compat_ip_setsockopt,
 591         .compat_getsockopt = compat_ip_getsockopt,
 592 #endif
 593 };
 594
 595 static const struct proto_ops l2tp_ip_ops = {
 596         .family            = PF_INET,
 597         .owner             = THIS_MODULE,
 598         .release           = inet_release,
 599         .bind              = inet_bind,
 600         .connect           = inet_dgram_connect,
 601         .socketpair        = sock_no_socketpair,
 602         .accept            = sock_no_accept,
 603         .getname           = l2tp_ip_getname,
 604         .poll              = datagram_poll,
 605         .ioctl             = inet_ioctl,
 606         .listen            = sock_no_listen,
 607         .shutdown          = inet_shutdown,
 608         .setsockopt        = sock_common_setsockopt,
 609         .getsockopt        = sock_common_getsockopt,
 610         .sendmsg           = inet_sendmsg,
 611         .recvmsg           = sock_common_recvmsg,
 612         .mmap              = sock_no_mmap,
 613         .sendpage          = sock_no_sendpage,
 614 #ifdef CONFIG_COMPAT
 615         .compat_setsockopt = compat_sock_common_setsockopt,
 616         .compat_getsockopt = compat_sock_common_getsockopt,
 617 #endif
 618 };
 619
 620 static struct inet_protosw l2tp_ip_protosw = {
 621         .type           = SOCK_DGRAM,
 622         .protocol       = IPPROTO_L2TP,
 623         .prot           = &l2tp_ip_prot,
 624         .ops            = &l2tp_ip_ops,
 625         .no_check       = 0,
 626 };
 627
 628 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 629         .handler        = l2tp_ip_recv,
 630 };
 631
 632 static int __init l2tp_ip_init(void)
 633 {
 634         int err;
 635
 636         printk(KERN_INFO "L2TP IP encapsulation support (L2TPv3)\n");
 637
 638         err = proto_register(&l2tp_ip_prot, 1);
 639         if (err != 0)
 640                 goto out;
 641
 642         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 643         if (err)
 644                 goto out1;
 645
 646         inet_register_protosw(&l2tp_ip_protosw);
 647         return 0;
 648
 649 out1:
 650         proto_unregister(&l2tp_ip_prot);
 651 out:
 652         return err;
 653 }
 654
 655 static void __exit l2tp_ip_exit(void)
 656 {
 657         inet_unregister_protosw(&l2tp_ip_protosw);
 658         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 659         proto_unregister(&l2tp_ip_prot);
 660 }
 661
 662 module_init(l2tp_ip_init);
 663 module_exit(l2tp_ip_exit);
 664
 665 MODULE_LICENSE("GPL");
 666 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 667 MODULE_DESCRIPTION("L2TP over IP");
 668 MODULE_VERSION("1.0");
 669
 670 /* Use the value of SOCK_DGRAM (2) directory, because __stringify does't like
 671  * enums
 672  */
 673 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);