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         int length;
 127
 128         if (!pskb_may_pull(skb, 4))
 129                 goto discard;
 130
 131         /* Point to L2TP header */
 132         optr = ptr = skb->data;
 133         session_id = ntohl(*((__be32 *) ptr));
 134         ptr += 4;
 135
 136         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 137          * the session_id. If it is 0, the packet is a L2TP control
 138          * frame and the session_id value can be discarded.
 139          */
 140         if (session_id == 0) {
 141                 __skb_pull(skb, 4);
 142                 goto pass_up;
 143         }
 144
 145         /* Ok, this is a data packet. Lookup the session. */
 146         session = l2tp_session_find(net, NULL, session_id);
 147         if (session == NULL)
 148                 goto discard;
 149
 150         tunnel = session->tunnel;
 151         if (tunnel == NULL)
 152                 goto discard;
 153
 154         /* Trace packet contents, if enabled */
 155         if (tunnel->debug & L2TP_MSG_DATA) {
 156                 length = min(32u, skb->len);
 157                 if (!pskb_may_pull(skb, length))
 158                         goto discard;
 159
 160                 /* Point to L2TP header */
 161                 optr = ptr = skb->data;
 162                 ptr += 4;
 163                 pr_debug("%s: ip recv\n", tunnel->name);
 164                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 165         }
 166
 167         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
 168
 169         return 0;
 170
 171 pass_up:
 172         /* Get the tunnel_id from the L2TP header */
 173         if (!pskb_may_pull(skb, 12))
 174                 goto discard;
 175
 176         if ((skb->data[0] & 0xc0) != 0xc0)
 177                 goto discard;
 178
 179         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 180         tunnel = l2tp_tunnel_find(net, tunnel_id);
 181         if (tunnel) {
 182                 sk = tunnel->sock;
 183                 sock_hold(sk);
 184         } else {
 185                 struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
 186
 187                 read_lock_bh(&l2tp_ip_lock);
 188                 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr,
 189                                            inet_iif(skb), tunnel_id);
 190                 if (!sk) {
 191                         read_unlock_bh(&l2tp_ip_lock);
 192                         goto discard;
 193                 }
 194
 195                 sock_hold(sk);
 196                 read_unlock_bh(&l2tp_ip_lock);
 197         }
 198
 199         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 200                 goto discard_put;
 201
 202         nf_reset(skb);
 203
 204         return sk_receive_skb(sk, skb, 1);
 205
 206 discard_put:
 207         sock_put(sk);
 208
 209 discard:
 210         kfree_skb(skb);
 211         return 0;
 212 }
 213
 214 static int l2tp_ip_open(struct sock *sk)
 215 {
 216         /* Prevent autobind. We don't have ports. */
 217         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 218
 219         write_lock_bh(&l2tp_ip_lock);
 220         sk_add_node(sk, &l2tp_ip_table);
 221         write_unlock_bh(&l2tp_ip_lock);
 222
 223         return 0;
 224 }
 225
 226 static void l2tp_ip_close(struct sock *sk, long timeout)
 227 {
 228         write_lock_bh(&l2tp_ip_lock);
 229         hlist_del_init(&sk->sk_bind_node);
 230         sk_del_node_init(sk);
 231         write_unlock_bh(&l2tp_ip_lock);
 232         sk_common_release(sk);
 233 }
 234
 235 static void l2tp_ip_destroy_sock(struct sock *sk)
 236 {
 237         struct sk_buff *skb;
 238         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 239
 240         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 241                 kfree_skb(skb);
 242
 243         if (tunnel) {
 244                 l2tp_tunnel_closeall(tunnel);
 245                 sock_put(sk);
 246         }
 247
 248         sk_refcnt_debug_dec(sk);
 249 }
 250
 251 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 252 {
 253         struct inet_sock *inet = inet_sk(sk);
 254         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 255         struct net *net = sock_net(sk);
 256         int ret;
 257         int chk_addr_ret;
 258
 259         if (addr_len < sizeof(struct sockaddr_l2tpip))
 260                 return -EINVAL;
 261         if (addr->l2tp_family != AF_INET)
 262                 return -EINVAL;
 263
 264         lock_sock(sk);
 265
 266         ret = -EINVAL;
 267         if (!sock_flag(sk, SOCK_ZAPPED))
 268                 goto out;
 269
 270         if (sk->sk_state != TCP_CLOSE)
 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
 284         write_lock_bh(&l2tp_ip_lock);
 285         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
 286                                   sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
 287                 write_unlock_bh(&l2tp_ip_lock);
 288                 ret = -EADDRINUSE;
 289                 goto out;
 290         }
 291
 292         sk_dst_reset(sk);
 293         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 294
 295         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 296         sk_del_node_init(sk);
 297         write_unlock_bh(&l2tp_ip_lock);
 298
 299         ret = 0;
 300         sock_reset_flag(sk, SOCK_ZAPPED);
 301
 302 out:
 303         release_sock(sk);
 304
 305         return ret;
 306 }
 307
 308 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 309 {
 310         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 311         int rc;
 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         lock_sock(sk);
 320
 321         /* Must bind first - autobinding does not work */
 322         if (sock_flag(sk, SOCK_ZAPPED)) {
 323                 rc = -EINVAL;
 324                 goto out_sk;
 325         }
 326
 327         rc = __ip4_datagram_connect(sk, uaddr, addr_len);
 328         if (rc < 0)
 329                 goto out_sk;
 330
 331         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 332
 333         write_lock_bh(&l2tp_ip_lock);
 334         hlist_del_init(&sk->sk_bind_node);
 335         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 336         write_unlock_bh(&l2tp_ip_lock);
 337
 338 out_sk:
 339         release_sock(sk);
 340
 341         return rc;
 342 }
 343
 344 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 345 {
 346         if (sock_flag(sk, SOCK_ZAPPED))
 347                 return 0;
 348
 349         return __udp_disconnect(sk, flags);
 350 }
 351
 352 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 353                            int *uaddr_len, int peer)
 354 {
 355         struct sock *sk         = sock->sk;
 356         struct inet_sock *inet  = inet_sk(sk);
 357         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 358         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 359
 360         memset(lsa, 0, sizeof(*lsa));
 361         lsa->l2tp_family = AF_INET;
 362         if (peer) {
 363                 if (!inet->inet_dport)
 364                         return -ENOTCONN;
 365                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 366                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 367         } else {
 368                 __be32 addr = inet->inet_rcv_saddr;
 369                 if (!addr)
 370                         addr = inet->inet_saddr;
 371                 lsa->l2tp_conn_id = lsk->conn_id;
 372                 lsa->l2tp_addr.s_addr = addr;
 373         }
 374         *uaddr_len = sizeof(*lsa);
 375         return 0;
 376 }
 377
 378 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 379 {
 380         int rc;
 381
 382         /* Charge it to the socket, dropping if the queue is full. */
 383         rc = sock_queue_rcv_skb(sk, skb);
 384         if (rc < 0)
 385                 goto drop;
 386
 387         return 0;
 388
 389 drop:
 390         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 391         kfree_skb(skb);
 392         return 0;
 393 }
 394
 395 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 396  * control frames.
 397  */
 398 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 399 {
 400         struct sk_buff *skb;
 401         int rc;
 402         struct inet_sock *inet = inet_sk(sk);
 403         struct rtable *rt = NULL;
 404         struct flowi4 *fl4;
 405         int connected = 0;
 406         __be32 daddr;
 407
 408         lock_sock(sk);
 409
 410         rc = -ENOTCONN;
 411         if (sock_flag(sk, SOCK_DEAD))
 412                 goto out;
 413
 414         /* Get and verify the address. */
 415         if (msg->msg_name) {
 416                 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
 417                 rc = -EINVAL;
 418                 if (msg->msg_namelen < sizeof(*lip))
 419                         goto out;
 420
 421                 if (lip->l2tp_family != AF_INET) {
 422                         rc = -EAFNOSUPPORT;
 423                         if (lip->l2tp_family != AF_UNSPEC)
 424                                 goto out;
 425                 }
 426
 427                 daddr = lip->l2tp_addr.s_addr;
 428         } else {
 429                 rc = -EDESTADDRREQ;
 430                 if (sk->sk_state != TCP_ESTABLISHED)
 431                         goto out;
 432
 433                 daddr = inet->inet_daddr;
 434                 connected = 1;
 435         }
 436
 437         /* Allocate a socket buffer */
 438         rc = -ENOMEM;
 439         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 440                            4 + len, 0, GFP_KERNEL);
 441         if (!skb)
 442                 goto error;
 443
 444         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 445         skb_reserve(skb, 2 + NET_SKB_PAD);
 446         skb_reset_network_header(skb);
 447         skb_reserve(skb, sizeof(struct iphdr));
 448         skb_reset_transport_header(skb);
 449
 450         /* Insert 0 session_id */
 451         *((__be32 *) skb_put(skb, 4)) = 0;
 452
 453         /* Copy user data into skb */
 454         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 455         if (rc < 0) {
 456                 kfree_skb(skb);
 457                 goto error;
 458         }
 459
 460         fl4 = &inet->cork.fl.u.ip4;
 461         if (connected)
 462                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 463
 464         rcu_read_lock();
 465         if (rt == NULL) {
 466                 const struct ip_options_rcu *inet_opt;
 467
 468                 inet_opt = rcu_dereference(inet->inet_opt);
 469
 470                 /* Use correct destination address if we have options. */
 471                 if (inet_opt && inet_opt->opt.srr)
 472                         daddr = inet_opt->opt.faddr;
 473
 474                 /* If this fails, retransmit mechanism of transport layer will
 475                  * keep trying until route appears or the connection times
 476                  * itself out.
 477                  */
 478                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 479                                            daddr, inet->inet_saddr,
 480                                            inet->inet_dport, inet->inet_sport,
 481                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 482                                            sk->sk_bound_dev_if);
 483                 if (IS_ERR(rt))
 484                         goto no_route;
 485                 if (connected) {
 486                         sk_setup_caps(sk, &rt->dst);
 487                 } else {
 488                         skb_dst_set(skb, &rt->dst);
 489                         goto xmit;
 490                 }
 491         }
 492
 493         /* We dont need to clone dst here, it is guaranteed to not disappear.
 494          *  __dev_xmit_skb() might force a refcount if needed.
 495          */
 496         skb_dst_set_noref(skb, &rt->dst);
 497
 498 xmit:
 499         /* Queue the packet to IP for output */
 500         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 501         rcu_read_unlock();
 502
 503 error:
 504         if (rc >= 0)
 505                 rc = len;
 506
 507 out:
 508         release_sock(sk);
 509         return rc;
 510
 511 no_route:
 512         rcu_read_unlock();
 513         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 514         kfree_skb(skb);
 515         rc = -EHOSTUNREACH;
 516         goto out;
 517 }
 518
 519 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 520                            size_t len, int noblock, int flags, int *addr_len)
 521 {
 522         struct inet_sock *inet = inet_sk(sk);
 523         size_t copied = 0;
 524         int err = -EOPNOTSUPP;
 525         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 526         struct sk_buff *skb;
 527
 528         if (flags & MSG_OOB)
 529                 goto out;
 530
 531         skb = skb_recv_datagram(sk, flags, noblock, &err);
 532         if (!skb)
 533                 goto out;
 534
 535         copied = skb->len;
 536         if (len < copied) {
 537                 msg->msg_flags |= MSG_TRUNC;
 538                 copied = len;
 539         }
 540
 541         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 542         if (err)
 543                 goto done;
 544
 545         sock_recv_timestamp(msg, sk, skb);
 546
 547         /* Copy the address. */
 548         if (sin) {
 549                 sin->sin_family = AF_INET;
 550                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 551                 sin->sin_port = 0;
 552                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 553                 *addr_len = sizeof(*sin);
 554         }
 555         if (inet->cmsg_flags)
 556                 ip_cmsg_recv(msg, skb);
 557         if (flags & MSG_TRUNC)
 558                 copied = skb->len;
 559 done:
 560         skb_free_datagram(sk, skb);
 561 out:
 562         return err ? err : copied;
 563 }
 564
 565 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 566 {
 567         struct sk_buff *skb;
 568         int amount;
 569
 570         switch (cmd) {
 571         case SIOCOUTQ:
 572                 amount = sk_wmem_alloc_get(sk);
 573                 break;
 574         case SIOCINQ:
 575                 spin_lock_bh(&sk->sk_receive_queue.lock);
 576                 skb = skb_peek(&sk->sk_receive_queue);
 577                 amount = skb ? skb->len : 0;
 578                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 579                 break;
 580
 581         default:
 582                 return -ENOIOCTLCMD;
 583         }
 584
 585         return put_user(amount, (int __user *)arg);
 586 }
 587 EXPORT_SYMBOL(l2tp_ioctl);
 588
 589 static struct proto l2tp_ip_prot = {
 590         .name              = "L2TP/IP",
 591         .owner             = THIS_MODULE,
 592         .init              = l2tp_ip_open,
 593         .close             = l2tp_ip_close,
 594         .bind              = l2tp_ip_bind,
 595         .connect           = l2tp_ip_connect,
 596         .disconnect        = l2tp_ip_disconnect,
 597         .ioctl             = l2tp_ioctl,
 598         .destroy           = l2tp_ip_destroy_sock,
 599         .setsockopt        = ip_setsockopt,
 600         .getsockopt        = ip_getsockopt,
 601         .sendmsg           = l2tp_ip_sendmsg,
 602         .recvmsg           = l2tp_ip_recvmsg,
 603         .backlog_rcv       = l2tp_ip_backlog_recv,
 604         .hash              = inet_hash,
 605         .unhash            = inet_unhash,
 606         .obj_size          = sizeof(struct l2tp_ip_sock),
 607 #ifdef CONFIG_COMPAT
 608         .compat_setsockopt = compat_ip_setsockopt,
 609         .compat_getsockopt = compat_ip_getsockopt,
 610 #endif
 611 };
 612
 613 static const struct proto_ops l2tp_ip_ops = {
 614         .family            = PF_INET,
 615         .owner             = THIS_MODULE,
 616         .release           = inet_release,
 617         .bind              = inet_bind,
 618         .connect           = inet_dgram_connect,
 619         .socketpair        = sock_no_socketpair,
 620         .accept            = sock_no_accept,
 621         .getname           = l2tp_ip_getname,
 622         .poll              = datagram_poll,
 623         .ioctl             = inet_ioctl,
 624         .listen            = sock_no_listen,
 625         .shutdown          = inet_shutdown,
 626         .setsockopt        = sock_common_setsockopt,
 627         .getsockopt        = sock_common_getsockopt,
 628         .sendmsg           = inet_sendmsg,
 629         .recvmsg           = sock_common_recvmsg,
 630         .mmap              = sock_no_mmap,
 631         .sendpage          = sock_no_sendpage,
 632 #ifdef CONFIG_COMPAT
 633         .compat_setsockopt = compat_sock_common_setsockopt,
 634         .compat_getsockopt = compat_sock_common_getsockopt,
 635 #endif
 636 };
 637
 638 static struct inet_protosw l2tp_ip_protosw = {
 639         .type           = SOCK_DGRAM,
 640         .protocol       = IPPROTO_L2TP,
 641         .prot           = &l2tp_ip_prot,
 642         .ops            = &l2tp_ip_ops,
 643 };
 644
 645 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 646         .handler        = l2tp_ip_recv,
 647         .netns_ok       = 1,
 648 };
 649
 650 static int __init l2tp_ip_init(void)
 651 {
 652         int err;
 653
 654         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 655
 656         err = proto_register(&l2tp_ip_prot, 1);
 657         if (err != 0)
 658                 goto out;
 659
 660         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 661         if (err)
 662                 goto out1;
 663
 664         inet_register_protosw(&l2tp_ip_protosw);
 665         return 0;
 666
 667 out1:
 668         proto_unregister(&l2tp_ip_prot);
 669 out:
 670         return err;
 671 }
 672
 673 static void __exit l2tp_ip_exit(void)
 674 {
 675         inet_unregister_protosw(&l2tp_ip_protosw);
 676         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 677         proto_unregister(&l2tp_ip_prot);
 678 }
 679
 680 module_init(l2tp_ip_init);
 681 module_exit(l2tp_ip_exit);
 682
 683 MODULE_LICENSE("GPL");
 684 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 685 MODULE_DESCRIPTION("L2TP over IP");
 686 MODULE_VERSION("1.0");
 687
 688 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 689  * enums
 690  */
 691 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 692 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);