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                 struct inet_sock *inet = inet_sk(sk);
  58                 struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
  59
  60                 if (l2tp == NULL)
  61                         continue;
  62
  63                 if ((l2tp->conn_id == tunnel_id) &&
  64                     net_eq(sock_net(sk), net) &&
  65                     !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
  66                     (!inet->inet_daddr || !raddr || inet->inet_daddr == raddr) &&
  67                     (!sk->sk_bound_dev_if || !dif ||
  68                      sk->sk_bound_dev_if == dif))
  69                         goto found;
  70         }
  71
  72         sk = NULL;
  73 found:
  74         return sk;
  75 }
  76
  77 /* When processing receive frames, there are two cases to
  78  * consider. Data frames consist of a non-zero session-id and an
  79  * optional cookie. Control frames consist of a regular L2TP header
  80  * preceded by 32-bits of zeros.
  81  *
  82  * L2TPv3 Session Header Over IP
  83  *
  84  *  0                   1                   2                   3
  85  *  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
  86  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  87  * |                           Session ID                          |
  88  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  89  * |               Cookie (optional, maximum 64 bits)...
  90  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  91  *                                                                 |
  92  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  93  *
  94  * L2TPv3 Control Message Header Over IP
  95  *
  96  *  0                   1                   2                   3
  97  *  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
  98  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  99  * |                      (32 bits of zeros)                       |
 100  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 101  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 102  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 103  * |                     Control Connection ID                     |
 104  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 105  * |               Ns              |               Nr              |
 106  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 107  *
 108  * All control frames are passed to userspace.
 109  */
 110 static int l2tp_ip_recv(struct sk_buff *skb)
 111 {
 112         struct net *net = dev_net(skb->dev);
 113         struct sock *sk;
 114         u32 session_id;
 115         u32 tunnel_id;
 116         unsigned char *ptr, *optr;
 117         struct l2tp_session *session;
 118         struct l2tp_tunnel *tunnel = NULL;
 119         int length;
 120
 121         if (!pskb_may_pull(skb, 4))
 122                 goto discard;
 123
 124         /* Point to L2TP header */
 125         optr = ptr = skb->data;
 126         session_id = ntohl(*((__be32 *) ptr));
 127         ptr += 4;
 128
 129         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 130          * the session_id. If it is 0, the packet is a L2TP control
 131          * frame and the session_id value can be discarded.
 132          */
 133         if (session_id == 0) {
 134                 __skb_pull(skb, 4);
 135                 goto pass_up;
 136         }
 137
 138         /* Ok, this is a data packet. Lookup the session. */
 139         session = l2tp_session_find(net, NULL, session_id);
 140         if (session == NULL)
 141                 goto discard;
 142
 143         tunnel = session->tunnel;
 144         if (tunnel == NULL)
 145                 goto discard;
 146
 147         /* Trace packet contents, if enabled */
 148         if (tunnel->debug & L2TP_MSG_DATA) {
 149                 length = min(32u, skb->len);
 150                 if (!pskb_may_pull(skb, length))
 151                         goto discard;
 152
 153                 /* Point to L2TP header */
 154                 optr = ptr = skb->data;
 155                 ptr += 4;
 156                 pr_debug("%s: ip recv\n", tunnel->name);
 157                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 158         }
 159
 160         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
 161
 162         return 0;
 163
 164 pass_up:
 165         /* Get the tunnel_id from the L2TP header */
 166         if (!pskb_may_pull(skb, 12))
 167                 goto discard;
 168
 169         if ((skb->data[0] & 0xc0) != 0xc0)
 170                 goto discard;
 171
 172         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 173         tunnel = l2tp_tunnel_find(net, tunnel_id);
 174         if (tunnel) {
 175                 sk = tunnel->sock;
 176                 sock_hold(sk);
 177         } else {
 178                 struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
 179
 180                 read_lock_bh(&l2tp_ip_lock);
 181                 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr,
 182                                            inet_iif(skb), tunnel_id);
 183                 if (!sk) {
 184                         read_unlock_bh(&l2tp_ip_lock);
 185                         goto discard;
 186                 }
 187
 188                 sock_hold(sk);
 189                 read_unlock_bh(&l2tp_ip_lock);
 190         }
 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         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 232
 233         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 234                 kfree_skb(skb);
 235
 236         if (tunnel) {
 237                 l2tp_tunnel_closeall(tunnel);
 238                 sock_put(sk);
 239         }
 240
 241         sk_refcnt_debug_dec(sk);
 242 }
 243
 244 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 245 {
 246         struct inet_sock *inet = inet_sk(sk);
 247         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 248         struct net *net = sock_net(sk);
 249         int ret;
 250         int chk_addr_ret;
 251
 252         if (addr_len < sizeof(struct sockaddr_l2tpip))
 253                 return -EINVAL;
 254         if (addr->l2tp_family != AF_INET)
 255                 return -EINVAL;
 256
 257         lock_sock(sk);
 258
 259         ret = -EINVAL;
 260         if (!sock_flag(sk, SOCK_ZAPPED))
 261                 goto out;
 262
 263         if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
 264                 goto out;
 265
 266         chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
 267         ret = -EADDRNOTAVAIL;
 268         if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
 269             chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 270                 goto out;
 271
 272         if (addr->l2tp_addr.s_addr)
 273                 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
 274         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 275                 inet->inet_saddr = 0;  /* Use device */
 276
 277         write_lock_bh(&l2tp_ip_lock);
 278         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
 279                                   sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
 280                 write_unlock_bh(&l2tp_ip_lock);
 281                 ret = -EADDRINUSE;
 282                 goto out;
 283         }
 284
 285         sk_dst_reset(sk);
 286         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 287
 288         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 289         sk_del_node_init(sk);
 290         write_unlock_bh(&l2tp_ip_lock);
 291
 292         ret = 0;
 293         sock_reset_flag(sk, SOCK_ZAPPED);
 294
 295 out:
 296         release_sock(sk);
 297
 298         return ret;
 299 }
 300
 301 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 302 {
 303         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 304         int rc;
 305
 306         if (addr_len < sizeof(*lsa))
 307                 return -EINVAL;
 308
 309         if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 310                 return -EINVAL;
 311
 312         lock_sock(sk);
 313
 314         /* Must bind first - autobinding does not work */
 315         if (sock_flag(sk, SOCK_ZAPPED)) {
 316                 rc = -EINVAL;
 317                 goto out_sk;
 318         }
 319
 320         rc = __ip4_datagram_connect(sk, uaddr, addr_len);
 321         if (rc < 0)
 322                 goto out_sk;
 323
 324         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 325
 326         write_lock_bh(&l2tp_ip_lock);
 327         hlist_del_init(&sk->sk_bind_node);
 328         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 329         write_unlock_bh(&l2tp_ip_lock);
 330
 331 out_sk:
 332         release_sock(sk);
 333
 334         return rc;
 335 }
 336
 337 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 338 {
 339         if (sock_flag(sk, SOCK_ZAPPED))
 340                 return 0;
 341
 342         return __udp_disconnect(sk, flags);
 343 }
 344
 345 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 346                            int *uaddr_len, int peer)
 347 {
 348         struct sock *sk         = sock->sk;
 349         struct inet_sock *inet  = inet_sk(sk);
 350         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 351         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 352
 353         memset(lsa, 0, sizeof(*lsa));
 354         lsa->l2tp_family = AF_INET;
 355         if (peer) {
 356                 if (!inet->inet_dport)
 357                         return -ENOTCONN;
 358                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 359                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 360         } else {
 361                 __be32 addr = inet->inet_rcv_saddr;
 362                 if (!addr)
 363                         addr = inet->inet_saddr;
 364                 lsa->l2tp_conn_id = lsk->conn_id;
 365                 lsa->l2tp_addr.s_addr = addr;
 366         }
 367         *uaddr_len = sizeof(*lsa);
 368         return 0;
 369 }
 370
 371 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 372 {
 373         int rc;
 374
 375         /* Charge it to the socket, dropping if the queue is full. */
 376         rc = sock_queue_rcv_skb(sk, skb);
 377         if (rc < 0)
 378                 goto drop;
 379
 380         return 0;
 381
 382 drop:
 383         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 384         kfree_skb(skb);
 385         return 0;
 386 }
 387
 388 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 389  * control frames.
 390  */
 391 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 392 {
 393         struct sk_buff *skb;
 394         int rc;
 395         struct inet_sock *inet = inet_sk(sk);
 396         struct rtable *rt = NULL;
 397         struct flowi4 *fl4;
 398         int connected = 0;
 399         __be32 daddr;
 400
 401         lock_sock(sk);
 402
 403         rc = -ENOTCONN;
 404         if (sock_flag(sk, SOCK_DEAD))
 405                 goto out;
 406
 407         /* Get and verify the address. */
 408         if (msg->msg_name) {
 409                 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
 410                 rc = -EINVAL;
 411                 if (msg->msg_namelen < sizeof(*lip))
 412                         goto out;
 413
 414                 if (lip->l2tp_family != AF_INET) {
 415                         rc = -EAFNOSUPPORT;
 416                         if (lip->l2tp_family != AF_UNSPEC)
 417                                 goto out;
 418                 }
 419
 420                 daddr = lip->l2tp_addr.s_addr;
 421         } else {
 422                 rc = -EDESTADDRREQ;
 423                 if (sk->sk_state != TCP_ESTABLISHED)
 424                         goto out;
 425
 426                 daddr = inet->inet_daddr;
 427                 connected = 1;
 428         }
 429
 430         /* Allocate a socket buffer */
 431         rc = -ENOMEM;
 432         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 433                            4 + len, 0, GFP_KERNEL);
 434         if (!skb)
 435                 goto error;
 436
 437         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 438         skb_reserve(skb, 2 + NET_SKB_PAD);
 439         skb_reset_network_header(skb);
 440         skb_reserve(skb, sizeof(struct iphdr));
 441         skb_reset_transport_header(skb);
 442
 443         /* Insert 0 session_id */
 444         *((__be32 *) skb_put(skb, 4)) = 0;
 445
 446         /* Copy user data into skb */
 447         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 448         if (rc < 0) {
 449                 kfree_skb(skb);
 450                 goto error;
 451         }
 452
 453         fl4 = &inet->cork.fl.u.ip4;
 454         if (connected)
 455                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 456
 457         rcu_read_lock();
 458         if (rt == NULL) {
 459                 const struct ip_options_rcu *inet_opt;
 460
 461                 inet_opt = rcu_dereference(inet->inet_opt);
 462
 463                 /* Use correct destination address if we have options. */
 464                 if (inet_opt && inet_opt->opt.srr)
 465                         daddr = inet_opt->opt.faddr;
 466
 467                 /* If this fails, retransmit mechanism of transport layer will
 468                  * keep trying until route appears or the connection times
 469                  * itself out.
 470                  */
 471                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 472                                            daddr, inet->inet_saddr,
 473                                            inet->inet_dport, inet->inet_sport,
 474                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 475                                            sk->sk_bound_dev_if);
 476                 if (IS_ERR(rt))
 477                         goto no_route;
 478                 if (connected) {
 479                         sk_setup_caps(sk, &rt->dst);
 480                 } else {
 481                         skb_dst_set(skb, &rt->dst);
 482                         goto xmit;
 483                 }
 484         }
 485
 486         /* We dont need to clone dst here, it is guaranteed to not disappear.
 487          *  __dev_xmit_skb() might force a refcount if needed.
 488          */
 489         skb_dst_set_noref(skb, &rt->dst);
 490
 491 xmit:
 492         /* Queue the packet to IP for output */
 493         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 494         rcu_read_unlock();
 495
 496 error:
 497         if (rc >= 0)
 498                 rc = len;
 499
 500 out:
 501         release_sock(sk);
 502         return rc;
 503
 504 no_route:
 505         rcu_read_unlock();
 506         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 507         kfree_skb(skb);
 508         rc = -EHOSTUNREACH;
 509         goto out;
 510 }
 511
 512 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 513                            size_t len, int noblock, int flags, int *addr_len)
 514 {
 515         struct inet_sock *inet = inet_sk(sk);
 516         size_t copied = 0;
 517         int err = -EOPNOTSUPP;
 518         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 519         struct sk_buff *skb;
 520
 521         if (flags & MSG_OOB)
 522                 goto out;
 523
 524         skb = skb_recv_datagram(sk, flags, noblock, &err);
 525         if (!skb)
 526                 goto out;
 527
 528         copied = skb->len;
 529         if (len < copied) {
 530                 msg->msg_flags |= MSG_TRUNC;
 531                 copied = len;
 532         }
 533
 534         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 535         if (err)
 536                 goto done;
 537
 538         sock_recv_timestamp(msg, sk, skb);
 539
 540         /* Copy the address. */
 541         if (sin) {
 542                 sin->sin_family = AF_INET;
 543                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 544                 sin->sin_port = 0;
 545                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 546                 *addr_len = sizeof(*sin);
 547         }
 548         if (inet->cmsg_flags)
 549                 ip_cmsg_recv(msg, skb);
 550         if (flags & MSG_TRUNC)
 551                 copied = skb->len;
 552 done:
 553         skb_free_datagram(sk, skb);
 554 out:
 555         return err ? err : copied;
 556 }
 557
 558 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 559 {
 560         struct sk_buff *skb;
 561         int amount;
 562
 563         switch (cmd) {
 564         case SIOCOUTQ:
 565                 amount = sk_wmem_alloc_get(sk);
 566                 break;
 567         case SIOCINQ:
 568                 spin_lock_bh(&sk->sk_receive_queue.lock);
 569                 skb = skb_peek(&sk->sk_receive_queue);
 570                 amount = skb ? skb->len : 0;
 571                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 572                 break;
 573
 574         default:
 575                 return -ENOIOCTLCMD;
 576         }
 577
 578         return put_user(amount, (int __user *)arg);
 579 }
 580 EXPORT_SYMBOL(l2tp_ioctl);
 581
 582 static struct proto l2tp_ip_prot = {
 583         .name              = "L2TP/IP",
 584         .owner             = THIS_MODULE,
 585         .init              = l2tp_ip_open,
 586         .close             = l2tp_ip_close,
 587         .bind              = l2tp_ip_bind,
 588         .connect           = l2tp_ip_connect,
 589         .disconnect        = l2tp_ip_disconnect,
 590         .ioctl             = l2tp_ioctl,
 591         .destroy           = l2tp_ip_destroy_sock,
 592         .setsockopt        = ip_setsockopt,
 593         .getsockopt        = ip_getsockopt,
 594         .sendmsg           = l2tp_ip_sendmsg,
 595         .recvmsg           = l2tp_ip_recvmsg,
 596         .backlog_rcv       = l2tp_ip_backlog_recv,
 597         .hash              = inet_hash,
 598         .unhash            = inet_unhash,
 599         .obj_size          = sizeof(struct l2tp_ip_sock),
 600 #ifdef CONFIG_COMPAT
 601         .compat_setsockopt = compat_ip_setsockopt,
 602         .compat_getsockopt = compat_ip_getsockopt,
 603 #endif
 604 };
 605
 606 static const struct proto_ops l2tp_ip_ops = {
 607         .family            = PF_INET,
 608         .owner             = THIS_MODULE,
 609         .release           = inet_release,
 610         .bind              = inet_bind,
 611         .connect           = inet_dgram_connect,
 612         .socketpair        = sock_no_socketpair,
 613         .accept            = sock_no_accept,
 614         .getname           = l2tp_ip_getname,
 615         .poll              = datagram_poll,
 616         .ioctl             = inet_ioctl,
 617         .listen            = sock_no_listen,
 618         .shutdown          = inet_shutdown,
 619         .setsockopt        = sock_common_setsockopt,
 620         .getsockopt        = sock_common_getsockopt,
 621         .sendmsg           = inet_sendmsg,
 622         .recvmsg           = sock_common_recvmsg,
 623         .mmap              = sock_no_mmap,
 624         .sendpage          = sock_no_sendpage,
 625 #ifdef CONFIG_COMPAT
 626         .compat_setsockopt = compat_sock_common_setsockopt,
 627         .compat_getsockopt = compat_sock_common_getsockopt,
 628 #endif
 629 };
 630
 631 static struct inet_protosw l2tp_ip_protosw = {
 632         .type           = SOCK_DGRAM,
 633         .protocol       = IPPROTO_L2TP,
 634         .prot           = &l2tp_ip_prot,
 635         .ops            = &l2tp_ip_ops,
 636 };
 637
 638 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 639         .handler        = l2tp_ip_recv,
 640         .netns_ok       = 1,
 641 };
 642
 643 static int __init l2tp_ip_init(void)
 644 {
 645         int err;
 646
 647         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 648
 649         err = proto_register(&l2tp_ip_prot, 1);
 650         if (err != 0)
 651                 goto out;
 652
 653         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 654         if (err)
 655                 goto out1;
 656
 657         inet_register_protosw(&l2tp_ip_protosw);
 658         return 0;
 659
 660 out1:
 661         proto_unregister(&l2tp_ip_prot);
 662 out:
 663         return err;
 664 }
 665
 666 static void __exit l2tp_ip_exit(void)
 667 {
 668         inet_unregister_protosw(&l2tp_ip_protosw);
 669         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 670         proto_unregister(&l2tp_ip_prot);
 671 }
 672
 673 module_init(l2tp_ip_init);
 674 module_exit(l2tp_ip_exit);
 675
 676 MODULE_LICENSE("GPL");
 677 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 678 MODULE_DESCRIPTION("L2TP over IP");
 679 MODULE_VERSION("1.0");
 680
 681 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 682  * enums
 683  */
 684 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 685 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);