net/l2tp/l2tp_ip.c

   1 /*
   2  * L2TPv3 IP encapsulation support
   3  *
   4  * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/icmp.h>
  15 #include <linux/module.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/random.h>
  18 #include <linux/socket.h>
  19 #include <linux/l2tp.h>
  20 #include <linux/in.h>
  21 #include <net/sock.h>
  22 #include <net/ip.h>
  23 #include <net/icmp.h>
  24 #include <net/udp.h>
  25 #include <net/inet_common.h>
  26 #include <net/inet_hashtables.h>
  27 #include <net/tcp_states.h>
  28 #include <net/protocol.h>
  29 #include <net/xfrm.h>
  30
  31 #include "l2tp_core.h"
  32
  33 struct l2tp_ip_sock {
  34         /* inet_sock has to be the first member of l2tp_ip_sock */
  35         struct inet_sock        inet;
  36
  37         u32                     conn_id;
  38         u32                     peer_conn_id;
  39 };
  40
  41 static DEFINE_RWLOCK(l2tp_ip_lock);
  42 static struct hlist_head l2tp_ip_table;
  43 static struct hlist_head l2tp_ip_bind_table;
  44
  45 static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
  46 {
  47         return (struct l2tp_ip_sock *)sk;
  48 }
  49
  50 static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
  51                                           __be32 raddr, int dif, u32 tunnel_id)
  52 {
  53         struct sock *sk;
  54
  55         sk_for_each_bound(sk, &l2tp_ip_bind_table) {
  56                 const struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
  57                 const struct inet_sock *inet = inet_sk(sk);
  58
  59                 if (!net_eq(sock_net(sk), net))
  60                         continue;
  61
  62                 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
  63                         continue;
  64
  65                 if (inet->inet_rcv_saddr && laddr &&
  66                     inet->inet_rcv_saddr != laddr)
  67                         continue;
  68
  69                 if (inet->inet_daddr && raddr && inet->inet_daddr != raddr)
  70                         continue;
  71
  72                 if (l2tp->conn_id != tunnel_id)
  73                         continue;
  74
  75                 goto found;
  76         }
  77
  78         sk = NULL;
  79 found:
  80         return sk;
  81 }
  82
  83 /* When processing receive frames, there are two cases to
  84  * consider. Data frames consist of a non-zero session-id and an
  85  * optional cookie. Control frames consist of a regular L2TP header
  86  * preceded by 32-bits of zeros.
  87  *
  88  * L2TPv3 Session Header Over IP
  89  *
  90  *  0                   1                   2                   3
  91  *  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
  92  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  93  * |                           Session ID                          |
  94  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  95  * |               Cookie (optional, maximum 64 bits)...
  96  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  97  *                                                                 |
  98  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  99  *
 100  * L2TPv3 Control Message Header Over IP
 101  *
 102  *  0                   1                   2                   3
 103  *  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
 104  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 105  * |                      (32 bits of zeros)                       |
 106  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 107  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 108  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 109  * |                     Control Connection ID                     |
 110  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 111  * |               Ns              |               Nr              |
 112  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 113  *
 114  * All control frames are passed to userspace.
 115  */
 116 static int l2tp_ip_recv(struct sk_buff *skb)
 117 {
 118         struct net *net = dev_net(skb->dev);
 119         struct sock *sk;
 120         u32 session_id;
 121         u32 tunnel_id;
 122         unsigned char *ptr, *optr;
 123         struct l2tp_session *session;
 124         struct l2tp_tunnel *tunnel = NULL;
 125         int length;
 126
 127         if (!pskb_may_pull(skb, 4))
 128                 goto discard;
 129
 130         /* Point to L2TP header */
 131         optr = ptr = skb->data;
 132         session_id = ntohl(*((__be32 *) ptr));
 133         ptr += 4;
 134
 135         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 136          * the session_id. If it is 0, the packet is a L2TP control
 137          * frame and the session_id value can be discarded.
 138          */
 139         if (session_id == 0) {
 140                 __skb_pull(skb, 4);
 141                 goto pass_up;
 142         }
 143
 144         /* Ok, this is a data packet. Lookup the session. */
 145         session = l2tp_session_find(net, NULL, session_id);
 146         if (session == NULL)
 147                 goto discard;
 148
 149         tunnel = session->tunnel;
 150         if (tunnel == NULL)
 151                 goto discard;
 152
 153         /* Trace packet contents, if enabled */
 154         if (tunnel->debug & L2TP_MSG_DATA) {
 155                 length = min(32u, skb->len);
 156                 if (!pskb_may_pull(skb, length))
 157                         goto discard;
 158
 159                 /* Point to L2TP header */
 160                 optr = ptr = skb->data;
 161                 ptr += 4;
 162                 pr_debug("%s: ip recv\n", tunnel->name);
 163                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 164         }
 165
 166         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
 167
 168         return 0;
 169
 170 pass_up:
 171         /* Get the tunnel_id from the L2TP header */
 172         if (!pskb_may_pull(skb, 12))
 173                 goto discard;
 174
 175         if ((skb->data[0] & 0xc0) != 0xc0)
 176                 goto discard;
 177
 178         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 179         tunnel = l2tp_tunnel_find(net, tunnel_id);
 180         if (tunnel != NULL)
 181                 sk = tunnel->sock;
 182         else {
 183                 struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
 184
 185                 read_lock_bh(&l2tp_ip_lock);
 186                 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr,
 187                                            inet_iif(skb), tunnel_id);
 188                 if (!sk) {
 189                         read_unlock_bh(&l2tp_ip_lock);
 190                         goto discard;
 191                 }
 192
 193                 sock_hold(sk);
 194                 read_unlock_bh(&l2tp_ip_lock);
 195         }
 196
 197         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 198                 goto discard_put;
 199
 200         nf_reset(skb);
 201
 202         return sk_receive_skb(sk, skb, 1);
 203
 204 discard_put:
 205         sock_put(sk);
 206
 207 discard:
 208         kfree_skb(skb);
 209         return 0;
 210 }
 211
 212 static int l2tp_ip_open(struct sock *sk)
 213 {
 214         /* Prevent autobind. We don't have ports. */
 215         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 216
 217         write_lock_bh(&l2tp_ip_lock);
 218         sk_add_node(sk, &l2tp_ip_table);
 219         write_unlock_bh(&l2tp_ip_lock);
 220
 221         return 0;
 222 }
 223
 224 static void l2tp_ip_close(struct sock *sk, long timeout)
 225 {
 226         write_lock_bh(&l2tp_ip_lock);
 227         hlist_del_init(&sk->sk_bind_node);
 228         sk_del_node_init(sk);
 229         write_unlock_bh(&l2tp_ip_lock);
 230         sk_common_release(sk);
 231 }
 232
 233 static void l2tp_ip_destroy_sock(struct sock *sk)
 234 {
 235         struct sk_buff *skb;
 236         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 237
 238         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 239                 kfree_skb(skb);
 240
 241         if (tunnel) {
 242                 l2tp_tunnel_closeall(tunnel);
 243                 sock_put(sk);
 244         }
 245
 246         sk_refcnt_debug_dec(sk);
 247 }
 248
 249 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 250 {
 251         struct inet_sock *inet = inet_sk(sk);
 252         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 253         struct net *net = sock_net(sk);
 254         int ret;
 255         int chk_addr_ret;
 256
 257         if (addr_len < sizeof(struct sockaddr_l2tpip))
 258                 return -EINVAL;
 259         if (addr->l2tp_family != AF_INET)
 260                 return -EINVAL;
 261
 262         lock_sock(sk);
 263
 264         ret = -EINVAL;
 265         if (!sock_flag(sk, SOCK_ZAPPED))
 266                 goto out;
 267
 268         if (sk->sk_state != TCP_CLOSE)
 269                 goto out;
 270
 271         chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
 272         ret = -EADDRNOTAVAIL;
 273         if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
 274             chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 275                 goto out;
 276
 277         if (addr->l2tp_addr.s_addr)
 278                 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
 279         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 280                 inet->inet_saddr = 0;  /* Use device */
 281
 282         write_lock_bh(&l2tp_ip_lock);
 283         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
 284                                   sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
 285                 write_unlock_bh(&l2tp_ip_lock);
 286                 ret = -EADDRINUSE;
 287                 goto out;
 288         }
 289
 290         sk_dst_reset(sk);
 291         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 292
 293         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 294         sk_del_node_init(sk);
 295         write_unlock_bh(&l2tp_ip_lock);
 296
 297         ret = 0;
 298         sock_reset_flag(sk, SOCK_ZAPPED);
 299
 300 out:
 301         release_sock(sk);
 302
 303         return ret;
 304 }
 305
 306 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 307 {
 308         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 309         int rc;
 310
 311         if (addr_len < sizeof(*lsa))
 312                 return -EINVAL;
 313
 314         if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 315                 return -EINVAL;
 316
 317         lock_sock(sk);
 318
 319         /* Must bind first - autobinding does not work */
 320         if (sock_flag(sk, SOCK_ZAPPED)) {
 321                 rc = -EINVAL;
 322                 goto out_sk;
 323         }
 324
 325         rc = __ip4_datagram_connect(sk, uaddr, addr_len);
 326         if (rc < 0)
 327                 goto out_sk;
 328
 329         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 330
 331         write_lock_bh(&l2tp_ip_lock);
 332         hlist_del_init(&sk->sk_bind_node);
 333         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 334         write_unlock_bh(&l2tp_ip_lock);
 335
 336 out_sk:
 337         release_sock(sk);
 338
 339         return rc;
 340 }
 341
 342 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 343 {
 344         if (sock_flag(sk, SOCK_ZAPPED))
 345                 return 0;
 346
 347         return __udp_disconnect(sk, flags);
 348 }
 349
 350 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 351                            int *uaddr_len, int peer)
 352 {
 353         struct sock *sk         = sock->sk;
 354         struct inet_sock *inet  = inet_sk(sk);
 355         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 356         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 357
 358         memset(lsa, 0, sizeof(*lsa));
 359         lsa->l2tp_family = AF_INET;
 360         if (peer) {
 361                 if (!inet->inet_dport)
 362                         return -ENOTCONN;
 363                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 364                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 365         } else {
 366                 __be32 addr = inet->inet_rcv_saddr;
 367                 if (!addr)
 368                         addr = inet->inet_saddr;
 369                 lsa->l2tp_conn_id = lsk->conn_id;
 370                 lsa->l2tp_addr.s_addr = addr;
 371         }
 372         *uaddr_len = sizeof(*lsa);
 373         return 0;
 374 }
 375
 376 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 377 {
 378         int rc;
 379
 380         /* Charge it to the socket, dropping if the queue is full. */
 381         rc = sock_queue_rcv_skb(sk, skb);
 382         if (rc < 0)
 383                 goto drop;
 384
 385         return 0;
 386
 387 drop:
 388         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 389         kfree_skb(skb);
 390         return -1;
 391 }
 392
 393 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 394  * control frames.
 395  */
 396 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 397 {
 398         struct sk_buff *skb;
 399         int rc;
 400         struct inet_sock *inet = inet_sk(sk);
 401         struct rtable *rt = NULL;
 402         struct flowi4 *fl4;
 403         int connected = 0;
 404         __be32 daddr;
 405
 406         lock_sock(sk);
 407
 408         rc = -ENOTCONN;
 409         if (sock_flag(sk, SOCK_DEAD))
 410                 goto out;
 411
 412         /* Get and verify the address. */
 413         if (msg->msg_name) {
 414                 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
 415                 rc = -EINVAL;
 416                 if (msg->msg_namelen < sizeof(*lip))
 417                         goto out;
 418
 419                 if (lip->l2tp_family != AF_INET) {
 420                         rc = -EAFNOSUPPORT;
 421                         if (lip->l2tp_family != AF_UNSPEC)
 422                                 goto out;
 423                 }
 424
 425                 daddr = lip->l2tp_addr.s_addr;
 426         } else {
 427                 rc = -EDESTADDRREQ;
 428                 if (sk->sk_state != TCP_ESTABLISHED)
 429                         goto out;
 430
 431                 daddr = inet->inet_daddr;
 432                 connected = 1;
 433         }
 434
 435         /* Allocate a socket buffer */
 436         rc = -ENOMEM;
 437         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 438                            4 + len, 0, GFP_KERNEL);
 439         if (!skb)
 440                 goto error;
 441
 442         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 443         skb_reserve(skb, 2 + NET_SKB_PAD);
 444         skb_reset_network_header(skb);
 445         skb_reserve(skb, sizeof(struct iphdr));
 446         skb_reset_transport_header(skb);
 447
 448         /* Insert 0 session_id */
 449         *((__be32 *) skb_put(skb, 4)) = 0;
 450
 451         /* Copy user data into skb */
 452         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 453         if (rc < 0) {
 454                 kfree_skb(skb);
 455                 goto error;
 456         }
 457
 458         fl4 = &inet->cork.fl.u.ip4;
 459         if (connected)
 460                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 461
 462         rcu_read_lock();
 463         if (rt == NULL) {
 464                 const struct ip_options_rcu *inet_opt;
 465
 466                 inet_opt = rcu_dereference(inet->inet_opt);
 467
 468                 /* Use correct destination address if we have options. */
 469                 if (inet_opt && inet_opt->opt.srr)
 470                         daddr = inet_opt->opt.faddr;
 471
 472                 /* If this fails, retransmit mechanism of transport layer will
 473                  * keep trying until route appears or the connection times
 474                  * itself out.
 475                  */
 476                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 477                                            daddr, inet->inet_saddr,
 478                                            inet->inet_dport, inet->inet_sport,
 479                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 480                                            sk->sk_bound_dev_if);
 481                 if (IS_ERR(rt))
 482                         goto no_route;
 483                 if (connected) {
 484                         sk_setup_caps(sk, &rt->dst);
 485                 } else {
 486                         skb_dst_set(skb, &rt->dst);
 487                         goto xmit;
 488                 }
 489         }
 490
 491         /* We dont need to clone dst here, it is guaranteed to not disappear.
 492          *  __dev_xmit_skb() might force a refcount if needed.
 493          */
 494         skb_dst_set_noref(skb, &rt->dst);
 495
 496 xmit:
 497         /* Queue the packet to IP for output */
 498         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 499         rcu_read_unlock();
 500
 501 error:
 502         if (rc >= 0)
 503                 rc = len;
 504
 505 out:
 506         release_sock(sk);
 507         return rc;
 508
 509 no_route:
 510         rcu_read_unlock();
 511         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 512         kfree_skb(skb);
 513         rc = -EHOSTUNREACH;
 514         goto out;
 515 }
 516
 517 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 518                            size_t len, int noblock, int flags, int *addr_len)
 519 {
 520         struct inet_sock *inet = inet_sk(sk);
 521         size_t copied = 0;
 522         int err = -EOPNOTSUPP;
 523         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 524         struct sk_buff *skb;
 525
 526         if (flags & MSG_OOB)
 527                 goto out;
 528
 529         skb = skb_recv_datagram(sk, flags, noblock, &err);
 530         if (!skb)
 531                 goto out;
 532
 533         copied = skb->len;
 534         if (len < copied) {
 535                 msg->msg_flags |= MSG_TRUNC;
 536                 copied = len;
 537         }
 538
 539         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 540         if (err)
 541                 goto done;
 542
 543         sock_recv_timestamp(msg, sk, skb);
 544
 545         /* Copy the address. */
 546         if (sin) {
 547                 sin->sin_family = AF_INET;
 548                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 549                 sin->sin_port = 0;
 550                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 551                 *addr_len = sizeof(*sin);
 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         return err ? err : copied;
 561 }
 562
 563 static struct proto l2tp_ip_prot = {
 564         .name              = "L2TP/IP",
 565         .owner             = THIS_MODULE,
 566         .init              = l2tp_ip_open,
 567         .close             = l2tp_ip_close,
 568         .bind              = l2tp_ip_bind,
 569         .connect           = l2tp_ip_connect,
 570         .disconnect        = l2tp_ip_disconnect,
 571         .ioctl             = udp_ioctl,
 572         .destroy           = l2tp_ip_destroy_sock,
 573         .setsockopt        = ip_setsockopt,
 574         .getsockopt        = ip_getsockopt,
 575         .sendmsg           = l2tp_ip_sendmsg,
 576         .recvmsg           = l2tp_ip_recvmsg,
 577         .backlog_rcv       = l2tp_ip_backlog_recv,
 578         .hash              = inet_hash,
 579         .unhash            = inet_unhash,
 580         .obj_size          = sizeof(struct l2tp_ip_sock),
 581 #ifdef CONFIG_COMPAT
 582         .compat_setsockopt = compat_ip_setsockopt,
 583         .compat_getsockopt = compat_ip_getsockopt,
 584 #endif
 585 };
 586
 587 static const struct proto_ops l2tp_ip_ops = {
 588         .family            = PF_INET,
 589         .owner             = THIS_MODULE,
 590         .release           = inet_release,
 591         .bind              = inet_bind,
 592         .connect           = inet_dgram_connect,
 593         .socketpair        = sock_no_socketpair,
 594         .accept            = sock_no_accept,
 595         .getname           = l2tp_ip_getname,
 596         .poll              = datagram_poll,
 597         .ioctl             = inet_ioctl,
 598         .listen            = sock_no_listen,
 599         .shutdown          = inet_shutdown,
 600         .setsockopt        = sock_common_setsockopt,
 601         .getsockopt        = sock_common_getsockopt,
 602         .sendmsg           = inet_sendmsg,
 603         .recvmsg           = sock_common_recvmsg,
 604         .mmap              = sock_no_mmap,
 605         .sendpage          = sock_no_sendpage,
 606 #ifdef CONFIG_COMPAT
 607         .compat_setsockopt = compat_sock_common_setsockopt,
 608         .compat_getsockopt = compat_sock_common_getsockopt,
 609 #endif
 610 };
 611
 612 static struct inet_protosw l2tp_ip_protosw = {
 613         .type           = SOCK_DGRAM,
 614         .protocol       = IPPROTO_L2TP,
 615         .prot           = &l2tp_ip_prot,
 616         .ops            = &l2tp_ip_ops,
 617 };
 618
 619 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 620         .handler        = l2tp_ip_recv,
 621         .netns_ok       = 1,
 622 };
 623
 624 static int __init l2tp_ip_init(void)
 625 {
 626         int err;
 627
 628         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 629
 630         err = proto_register(&l2tp_ip_prot, 1);
 631         if (err != 0)
 632                 goto out;
 633
 634         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 635         if (err)
 636                 goto out1;
 637
 638         inet_register_protosw(&l2tp_ip_protosw);
 639         return 0;
 640
 641 out1:
 642         proto_unregister(&l2tp_ip_prot);
 643 out:
 644         return err;
 645 }
 646
 647 static void __exit l2tp_ip_exit(void)
 648 {
 649         inet_unregister_protosw(&l2tp_ip_protosw);
 650         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 651         proto_unregister(&l2tp_ip_prot);
 652 }
 653
 654 module_init(l2tp_ip_init);
 655 module_exit(l2tp_ip_exit);
 656
 657 MODULE_LICENSE("GPL");
 658 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 659 MODULE_DESCRIPTION("L2TP over IP");
 660 MODULE_VERSION("1.0");
 661
 662 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 663  * enums
 664  */
 665 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 666 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);