net/l2tp/l2tp_ip.c

   1 /*
   2  * L2TPv3 IP encapsulation support
   3  *
   4  * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <asm/ioctls.h>
  15 #include <linux/icmp.h>
  16 #include <linux/module.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/random.h>
  19 #include <linux/socket.h>
  20 #include <linux/l2tp.h>
  21 #include <linux/in.h>
  22 #include <net/sock.h>
  23 #include <net/ip.h>
  24 #include <net/icmp.h>
  25 #include <net/udp.h>
  26 #include <net/inet_common.h>
  27 #include <net/inet_hashtables.h>
  28 #include <net/tcp_states.h>
  29 #include <net/protocol.h>
  30 #include <net/xfrm.h>
  31
  32 #include "l2tp_core.h"
  33
  34 struct l2tp_ip_sock {
  35         /* inet_sock has to be the first member of l2tp_ip_sock */
  36         struct inet_sock        inet;
  37
  38         u32                     conn_id;
  39         u32                     peer_conn_id;
  40 };
  41
  42 static DEFINE_RWLOCK(l2tp_ip_lock);
  43 static struct hlist_head l2tp_ip_table;
  44 static struct hlist_head l2tp_ip_bind_table;
  45
  46 static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
  47 {
  48         return (struct l2tp_ip_sock *)sk;
  49 }
  50
  51 static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
  52                                           __be32 raddr, int dif, u32 tunnel_id)
  53 {
  54         struct sock *sk;
  55
  56         sk_for_each_bound(sk, &l2tp_ip_bind_table) {
  57                 const struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
  58                 const struct inet_sock *inet = inet_sk(sk);
  59
  60                 if (!net_eq(sock_net(sk), net))
  61                         continue;
  62
  63                 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
  64                         continue;
  65
  66                 if (inet->inet_rcv_saddr && laddr &&
  67                     inet->inet_rcv_saddr != laddr)
  68                         continue;
  69
  70                 if (inet->inet_daddr && raddr && inet->inet_daddr != raddr)
  71                         continue;
  72
  73                 if (l2tp->conn_id != tunnel_id)
  74                         continue;
  75
  76                 goto found;
  77         }
  78
  79         sk = NULL;
  80 found:
  81         return sk;
  82 }
  83
  84 /* When processing receive frames, there are two cases to
  85  * consider. Data frames consist of a non-zero session-id and an
  86  * optional cookie. Control frames consist of a regular L2TP header
  87  * preceded by 32-bits of zeros.
  88  *
  89  * L2TPv3 Session Header Over IP
  90  *
  91  *  0                   1                   2                   3
  92  *  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
  93  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  94  * |                           Session ID                          |
  95  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  96  * |               Cookie (optional, maximum 64 bits)...
  97  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  98  *                                                                 |
  99  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 100  *
 101  * L2TPv3 Control Message Header Over IP
 102  *
 103  *  0                   1                   2                   3
 104  *  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
 105  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 106  * |                      (32 bits of zeros)                       |
 107  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 108  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 109  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 110  * |                     Control Connection ID                     |
 111  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 112  * |               Ns              |               Nr              |
 113  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 114  *
 115  * All control frames are passed to userspace.
 116  */
 117 static int l2tp_ip_recv(struct sk_buff *skb)
 118 {
 119         struct net *net = dev_net(skb->dev);
 120         struct sock *sk;
 121         u32 session_id;
 122         u32 tunnel_id;
 123         unsigned char *ptr, *optr;
 124         struct l2tp_session *session;
 125         struct l2tp_tunnel *tunnel = NULL;
 126         struct iphdr *iph;
 127         int length;
 128
 129         if (!pskb_may_pull(skb, 4))
 130                 goto discard;
 131
 132         /* Point to L2TP header */
 133         optr = ptr = skb->data;
 134         session_id = ntohl(*((__be32 *) ptr));
 135         ptr += 4;
 136
 137         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 138          * the session_id. If it is 0, the packet is a L2TP control
 139          * frame and the session_id value can be discarded.
 140          */
 141         if (session_id == 0) {
 142                 __skb_pull(skb, 4);
 143                 goto pass_up;
 144         }
 145
 146         /* Ok, this is a data packet. Lookup the session. */
 147         session = l2tp_session_get(net, NULL, session_id, true);
 148         if (!session)
 149                 goto discard;
 150
 151         tunnel = session->tunnel;
 152         if (!tunnel)
 153                 goto discard_sess;
 154
 155         /* Trace packet contents, if enabled */
 156         if (tunnel->debug & L2TP_MSG_DATA) {
 157                 length = min(32u, skb->len);
 158                 if (!pskb_may_pull(skb, length))
 159                         goto discard_sess;
 160
 161                 /* Point to L2TP header */
 162                 optr = ptr = skb->data;
 163                 ptr += 4;
 164                 pr_debug("%s: ip recv\n", tunnel->name);
 165                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 166         }
 167
 168         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
 169         l2tp_session_dec_refcount(session);
 170
 171         return 0;
 172
 173 pass_up:
 174         /* Get the tunnel_id from the L2TP header */
 175         if (!pskb_may_pull(skb, 12))
 176                 goto discard;
 177
 178         if ((skb->data[0] & 0xc0) != 0xc0)
 179                 goto discard;
 180
 181         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 182         iph = (struct iphdr *)skb_network_header(skb);
 183
 184         read_lock_bh(&l2tp_ip_lock);
 185         sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb),
 186                                    tunnel_id);
 187         if (!sk) {
 188                 read_unlock_bh(&l2tp_ip_lock);
 189                 goto discard;
 190         }
 191         sock_hold(sk);
 192         read_unlock_bh(&l2tp_ip_lock);
 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_sess:
 202         if (session->deref)
 203                 session->deref(session);
 204         l2tp_session_dec_refcount(session);
 205         goto discard;
 206
 207 discard_put:
 208         sock_put(sk);
 209
 210 discard:
 211         kfree_skb(skb);
 212         return 0;
 213 }
 214
 215 static int l2tp_ip_open(struct sock *sk)
 216 {
 217         /* Prevent autobind. We don't have ports. */
 218         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 219
 220         write_lock_bh(&l2tp_ip_lock);
 221         sk_add_node(sk, &l2tp_ip_table);
 222         write_unlock_bh(&l2tp_ip_lock);
 223
 224         return 0;
 225 }
 226
 227 static void l2tp_ip_close(struct sock *sk, long timeout)
 228 {
 229         write_lock_bh(&l2tp_ip_lock);
 230         hlist_del_init(&sk->sk_bind_node);
 231         sk_del_node_init(sk);
 232         write_unlock_bh(&l2tp_ip_lock);
 233         sk_common_release(sk);
 234 }
 235
 236 static void l2tp_ip_destroy_sock(struct sock *sk)
 237 {
 238         struct sk_buff *skb;
 239         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 240
 241         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 242                 kfree_skb(skb);
 243
 244         if (tunnel) {
 245                 l2tp_tunnel_closeall(tunnel);
 246                 sock_put(sk);
 247         }
 248
 249         sk_refcnt_debug_dec(sk);
 250 }
 251
 252 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 253 {
 254         struct inet_sock *inet = inet_sk(sk);
 255         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 256         struct net *net = sock_net(sk);
 257         int ret;
 258         int chk_addr_ret;
 259
 260         if (addr_len < sizeof(struct sockaddr_l2tpip))
 261                 return -EINVAL;
 262         if (addr->l2tp_family != AF_INET)
 263                 return -EINVAL;
 264
 265         lock_sock(sk);
 266
 267         ret = -EINVAL;
 268         if (!sock_flag(sk, SOCK_ZAPPED))
 269                 goto out;
 270
 271         if (sk->sk_state != TCP_CLOSE)
 272                 goto out;
 273
 274         chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
 275         ret = -EADDRNOTAVAIL;
 276         if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
 277             chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 278                 goto out;
 279
 280         if (addr->l2tp_addr.s_addr)
 281                 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
 282         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 283                 inet->inet_saddr = 0;  /* Use device */
 284
 285         write_lock_bh(&l2tp_ip_lock);
 286         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
 287                                   sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
 288                 write_unlock_bh(&l2tp_ip_lock);
 289                 ret = -EADDRINUSE;
 290                 goto out;
 291         }
 292
 293         sk_dst_reset(sk);
 294         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 295
 296         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 297         sk_del_node_init(sk);
 298         write_unlock_bh(&l2tp_ip_lock);
 299
 300         ret = 0;
 301         sock_reset_flag(sk, SOCK_ZAPPED);
 302
 303 out:
 304         release_sock(sk);
 305
 306         return ret;
 307 }
 308
 309 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 310 {
 311         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 312         int rc;
 313
 314         if (addr_len < sizeof(*lsa))
 315                 return -EINVAL;
 316
 317         if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 318                 return -EINVAL;
 319
 320         lock_sock(sk);
 321
 322         /* Must bind first - autobinding does not work */
 323         if (sock_flag(sk, SOCK_ZAPPED)) {
 324                 rc = -EINVAL;
 325                 goto out_sk;
 326         }
 327
 328         rc = __ip4_datagram_connect(sk, uaddr, addr_len);
 329         if (rc < 0)
 330                 goto out_sk;
 331
 332         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 333
 334         write_lock_bh(&l2tp_ip_lock);
 335         hlist_del_init(&sk->sk_bind_node);
 336         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 337         write_unlock_bh(&l2tp_ip_lock);
 338
 339 out_sk:
 340         release_sock(sk);
 341
 342         return rc;
 343 }
 344
 345 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 346 {
 347         if (sock_flag(sk, SOCK_ZAPPED))
 348                 return 0;
 349
 350         return __udp_disconnect(sk, flags);
 351 }
 352
 353 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 354                            int *uaddr_len, int peer)
 355 {
 356         struct sock *sk         = sock->sk;
 357         struct inet_sock *inet  = inet_sk(sk);
 358         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 359         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 360
 361         memset(lsa, 0, sizeof(*lsa));
 362         lsa->l2tp_family = AF_INET;
 363         if (peer) {
 364                 if (!inet->inet_dport)
 365                         return -ENOTCONN;
 366                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 367                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 368         } else {
 369                 __be32 addr = inet->inet_rcv_saddr;
 370                 if (!addr)
 371                         addr = inet->inet_saddr;
 372                 lsa->l2tp_conn_id = lsk->conn_id;
 373                 lsa->l2tp_addr.s_addr = addr;
 374         }
 375         *uaddr_len = sizeof(*lsa);
 376         return 0;
 377 }
 378
 379 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 380 {
 381         int rc;
 382
 383         /* Charge it to the socket, dropping if the queue is full. */
 384         rc = sock_queue_rcv_skb(sk, skb);
 385         if (rc < 0)
 386                 goto drop;
 387
 388         return 0;
 389
 390 drop:
 391         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 392         kfree_skb(skb);
 393         return 0;
 394 }
 395
 396 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 397  * control frames.
 398  */
 399 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 400 {
 401         struct sk_buff *skb;
 402         int rc;
 403         struct inet_sock *inet = inet_sk(sk);
 404         struct rtable *rt = NULL;
 405         struct flowi4 *fl4;
 406         int connected = 0;
 407         __be32 daddr;
 408
 409         lock_sock(sk);
 410
 411         rc = -ENOTCONN;
 412         if (sock_flag(sk, SOCK_DEAD))
 413                 goto out;
 414
 415         /* Get and verify the address. */
 416         if (msg->msg_name) {
 417                 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
 418                 rc = -EINVAL;
 419                 if (msg->msg_namelen < sizeof(*lip))
 420                         goto out;
 421
 422                 if (lip->l2tp_family != AF_INET) {
 423                         rc = -EAFNOSUPPORT;
 424                         if (lip->l2tp_family != AF_UNSPEC)
 425                                 goto out;
 426                 }
 427
 428                 daddr = lip->l2tp_addr.s_addr;
 429         } else {
 430                 rc = -EDESTADDRREQ;
 431                 if (sk->sk_state != TCP_ESTABLISHED)
 432                         goto out;
 433
 434                 daddr = inet->inet_daddr;
 435                 connected = 1;
 436         }
 437
 438         /* Allocate a socket buffer */
 439         rc = -ENOMEM;
 440         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 441                            4 + len, 0, GFP_KERNEL);
 442         if (!skb)
 443                 goto error;
 444
 445         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 446         skb_reserve(skb, 2 + NET_SKB_PAD);
 447         skb_reset_network_header(skb);
 448         skb_reserve(skb, sizeof(struct iphdr));
 449         skb_reset_transport_header(skb);
 450
 451         /* Insert 0 session_id */
 452         *((__be32 *) skb_put(skb, 4)) = 0;
 453
 454         /* Copy user data into skb */
 455         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 456         if (rc < 0) {
 457                 kfree_skb(skb);
 458                 goto error;
 459         }
 460
 461         fl4 = &inet->cork.fl.u.ip4;
 462         if (connected)
 463                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 464
 465         rcu_read_lock();
 466         if (rt == NULL) {
 467                 const struct ip_options_rcu *inet_opt;
 468
 469                 inet_opt = rcu_dereference(inet->inet_opt);
 470
 471                 /* Use correct destination address if we have options. */
 472                 if (inet_opt && inet_opt->opt.srr)
 473                         daddr = inet_opt->opt.faddr;
 474
 475                 /* If this fails, retransmit mechanism of transport layer will
 476                  * keep trying until route appears or the connection times
 477                  * itself out.
 478                  */
 479                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 480                                            daddr, inet->inet_saddr,
 481                                            inet->inet_dport, inet->inet_sport,
 482                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 483                                            sk->sk_bound_dev_if);
 484                 if (IS_ERR(rt))
 485                         goto no_route;
 486                 if (connected) {
 487                         sk_setup_caps(sk, &rt->dst);
 488                 } else {
 489                         skb_dst_set(skb, &rt->dst);
 490                         goto xmit;
 491                 }
 492         }
 493
 494         /* We dont need to clone dst here, it is guaranteed to not disappear.
 495          *  __dev_xmit_skb() might force a refcount if needed.
 496          */
 497         skb_dst_set_noref(skb, &rt->dst);
 498
 499 xmit:
 500         /* Queue the packet to IP for output */
 501         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 502         rcu_read_unlock();
 503
 504 error:
 505         if (rc >= 0)
 506                 rc = len;
 507
 508 out:
 509         release_sock(sk);
 510         return rc;
 511
 512 no_route:
 513         rcu_read_unlock();
 514         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 515         kfree_skb(skb);
 516         rc = -EHOSTUNREACH;
 517         goto out;
 518 }
 519
 520 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 521                            size_t len, int noblock, int flags, int *addr_len)
 522 {
 523         struct inet_sock *inet = inet_sk(sk);
 524         size_t copied = 0;
 525         int err = -EOPNOTSUPP;
 526         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 527         struct sk_buff *skb;
 528
 529         if (flags & MSG_OOB)
 530                 goto out;
 531
 532         skb = skb_recv_datagram(sk, flags, noblock, &err);
 533         if (!skb)
 534                 goto out;
 535
 536         copied = skb->len;
 537         if (len < copied) {
 538                 msg->msg_flags |= MSG_TRUNC;
 539                 copied = len;
 540         }
 541
 542         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 543         if (err)
 544                 goto done;
 545
 546         sock_recv_timestamp(msg, sk, skb);
 547
 548         /* Copy the address. */
 549         if (sin) {
 550                 sin->sin_family = AF_INET;
 551                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 552                 sin->sin_port = 0;
 553                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 554                 *addr_len = sizeof(*sin);
 555         }
 556         if (inet->cmsg_flags)
 557                 ip_cmsg_recv(msg, skb);
 558         if (flags & MSG_TRUNC)
 559                 copied = skb->len;
 560 done:
 561         skb_free_datagram(sk, skb);
 562 out:
 563         return err ? err : copied;
 564 }
 565
 566 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 567 {
 568         struct sk_buff *skb;
 569         int amount;
 570
 571         switch (cmd) {
 572         case SIOCOUTQ:
 573                 amount = sk_wmem_alloc_get(sk);
 574                 break;
 575         case SIOCINQ:
 576                 spin_lock_bh(&sk->sk_receive_queue.lock);
 577                 skb = skb_peek(&sk->sk_receive_queue);
 578                 amount = skb ? skb->len : 0;
 579                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 580                 break;
 581
 582         default:
 583                 return -ENOIOCTLCMD;
 584         }
 585
 586         return put_user(amount, (int __user *)arg);
 587 }
 588 EXPORT_SYMBOL(l2tp_ioctl);
 589
 590 static struct proto l2tp_ip_prot = {
 591         .name              = "L2TP/IP",
 592         .owner             = THIS_MODULE,
 593         .init              = l2tp_ip_open,
 594         .close             = l2tp_ip_close,
 595         .bind              = l2tp_ip_bind,
 596         .connect           = l2tp_ip_connect,
 597         .disconnect        = l2tp_ip_disconnect,
 598         .ioctl             = l2tp_ioctl,
 599         .destroy           = l2tp_ip_destroy_sock,
 600         .setsockopt        = ip_setsockopt,
 601         .getsockopt        = ip_getsockopt,
 602         .sendmsg           = l2tp_ip_sendmsg,
 603         .recvmsg           = l2tp_ip_recvmsg,
 604         .backlog_rcv       = l2tp_ip_backlog_recv,
 605         .hash              = inet_hash,
 606         .unhash            = inet_unhash,
 607         .obj_size          = sizeof(struct l2tp_ip_sock),
 608 #ifdef CONFIG_COMPAT
 609         .compat_setsockopt = compat_ip_setsockopt,
 610         .compat_getsockopt = compat_ip_getsockopt,
 611 #endif
 612 };
 613
 614 static const struct proto_ops l2tp_ip_ops = {
 615         .family            = PF_INET,
 616         .owner             = THIS_MODULE,
 617         .release           = inet_release,
 618         .bind              = inet_bind,
 619         .connect           = inet_dgram_connect,
 620         .socketpair        = sock_no_socketpair,
 621         .accept            = sock_no_accept,
 622         .getname           = l2tp_ip_getname,
 623         .poll              = datagram_poll,
 624         .ioctl             = inet_ioctl,
 625         .listen            = sock_no_listen,
 626         .shutdown          = inet_shutdown,
 627         .setsockopt        = sock_common_setsockopt,
 628         .getsockopt        = sock_common_getsockopt,
 629         .sendmsg           = inet_sendmsg,
 630         .recvmsg           = sock_common_recvmsg,
 631         .mmap              = sock_no_mmap,
 632         .sendpage          = sock_no_sendpage,
 633 #ifdef CONFIG_COMPAT
 634         .compat_setsockopt = compat_sock_common_setsockopt,
 635         .compat_getsockopt = compat_sock_common_getsockopt,
 636 #endif
 637 };
 638
 639 static struct inet_protosw l2tp_ip_protosw = {
 640         .type           = SOCK_DGRAM,
 641         .protocol       = IPPROTO_L2TP,
 642         .prot           = &l2tp_ip_prot,
 643         .ops            = &l2tp_ip_ops,
 644 };
 645
 646 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 647         .handler        = l2tp_ip_recv,
 648         .netns_ok       = 1,
 649 };
 650
 651 static int __init l2tp_ip_init(void)
 652 {
 653         int err;
 654
 655         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 656
 657         err = proto_register(&l2tp_ip_prot, 1);
 658         if (err != 0)
 659                 goto out;
 660
 661         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 662         if (err)
 663                 goto out1;
 664
 665         inet_register_protosw(&l2tp_ip_protosw);
 666         return 0;
 667
 668 out1:
 669         proto_unregister(&l2tp_ip_prot);
 670 out:
 671         return err;
 672 }
 673
 674 static void __exit l2tp_ip_exit(void)
 675 {
 676         inet_unregister_protosw(&l2tp_ip_protosw);
 677         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 678         proto_unregister(&l2tp_ip_prot);
 679 }
 680
 681 module_init(l2tp_ip_init);
 682 module_exit(l2tp_ip_exit);
 683
 684 MODULE_LICENSE("GPL");
 685 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 686 MODULE_DESCRIPTION("L2TP over IP");
 687 MODULE_VERSION("1.0");
 688
 689 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 690  * enums
 691  */
 692 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 693 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);