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                 struct inet_sock *inet = inet_sk(sk);
  57                 struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
  58
  59                 if (l2tp == NULL)
  60                         continue;
  61
  62                 if ((l2tp->conn_id == tunnel_id) &&
  63                     net_eq(sock_net(sk), net) &&
  64                     !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
  65                     (!inet->inet_daddr || !raddr || inet->inet_daddr == raddr) &&
  66                     (!sk->sk_bound_dev_if || !dif ||
  67                      sk->sk_bound_dev_if == dif))
  68                         goto found;
  69         }
  70
  71         sk = NULL;
  72 found:
  73         return sk;
  74 }
  75
  76 /* When processing receive frames, there are two cases to
  77  * consider. Data frames consist of a non-zero session-id and an
  78  * optional cookie. Control frames consist of a regular L2TP header
  79  * preceded by 32-bits of zeros.
  80  *
  81  * L2TPv3 Session Header Over IP
  82  *
  83  *  0                   1                   2                   3
  84  *  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
  85  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  86  * |                           Session ID                          |
  87  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  88  * |               Cookie (optional, maximum 64 bits)...
  89  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  90  *                                                                 |
  91  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  92  *
  93  * L2TPv3 Control Message Header Over IP
  94  *
  95  *  0                   1                   2                   3
  96  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  97  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  98  * |                      (32 bits of zeros)                       |
  99  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 100  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 101  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 102  * |                     Control Connection ID                     |
 103  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 104  * |               Ns              |               Nr              |
 105  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 106  *
 107  * All control frames are passed to userspace.
 108  */
 109 static int l2tp_ip_recv(struct sk_buff *skb)
 110 {
 111         struct net *net = dev_net(skb->dev);
 112         struct sock *sk;
 113         u32 session_id;
 114         u32 tunnel_id;
 115         unsigned char *ptr, *optr;
 116         struct l2tp_session *session;
 117         struct l2tp_tunnel *tunnel = NULL;
 118         int length;
 119
 120         if (!pskb_may_pull(skb, 4))
 121                 goto discard;
 122
 123         /* Point to L2TP header */
 124         optr = ptr = skb->data;
 125         session_id = ntohl(*((__be32 *) ptr));
 126         ptr += 4;
 127
 128         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 129          * the session_id. If it is 0, the packet is a L2TP control
 130          * frame and the session_id value can be discarded.
 131          */
 132         if (session_id == 0) {
 133                 __skb_pull(skb, 4);
 134                 goto pass_up;
 135         }
 136
 137         /* Ok, this is a data packet. Lookup the session. */
 138         session = l2tp_session_find(net, NULL, session_id);
 139         if (session == NULL)
 140                 goto discard;
 141
 142         tunnel = session->tunnel;
 143         if (tunnel == NULL)
 144                 goto discard;
 145
 146         /* Trace packet contents, if enabled */
 147         if (tunnel->debug & L2TP_MSG_DATA) {
 148                 length = min(32u, skb->len);
 149                 if (!pskb_may_pull(skb, length))
 150                         goto discard;
 151
 152                 /* Point to L2TP header */
 153                 optr = ptr = skb->data;
 154                 ptr += 4;
 155                 pr_debug("%s: ip recv\n", tunnel->name);
 156                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 157         }
 158
 159         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
 160
 161         return 0;
 162
 163 pass_up:
 164         /* Get the tunnel_id from the L2TP header */
 165         if (!pskb_may_pull(skb, 12))
 166                 goto discard;
 167
 168         if ((skb->data[0] & 0xc0) != 0xc0)
 169                 goto discard;
 170
 171         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 172         tunnel = l2tp_tunnel_find(net, tunnel_id);
 173         if (tunnel != NULL)
 174                 sk = tunnel->sock;
 175         else {
 176                 struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
 177
 178                 read_lock_bh(&l2tp_ip_lock);
 179                 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr,
 180                                            inet_iif(skb), tunnel_id);
 181                 if (!sk) {
 182                         read_unlock_bh(&l2tp_ip_lock);
 183                         goto discard;
 184                 }
 185
 186                 sock_hold(sk);
 187                 read_unlock_bh(&l2tp_ip_lock);
 188         }
 189
 190         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 191                 goto discard_put;
 192
 193         nf_reset(skb);
 194
 195         return sk_receive_skb(sk, skb, 1);
 196
 197 discard_put:
 198         sock_put(sk);
 199
 200 discard:
 201         kfree_skb(skb);
 202         return 0;
 203 }
 204
 205 static int l2tp_ip_open(struct sock *sk)
 206 {
 207         /* Prevent autobind. We don't have ports. */
 208         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 209
 210         write_lock_bh(&l2tp_ip_lock);
 211         sk_add_node(sk, &l2tp_ip_table);
 212         write_unlock_bh(&l2tp_ip_lock);
 213
 214         return 0;
 215 }
 216
 217 static void l2tp_ip_close(struct sock *sk, long timeout)
 218 {
 219         write_lock_bh(&l2tp_ip_lock);
 220         hlist_del_init(&sk->sk_bind_node);
 221         sk_del_node_init(sk);
 222         write_unlock_bh(&l2tp_ip_lock);
 223         sk_common_release(sk);
 224 }
 225
 226 static void l2tp_ip_destroy_sock(struct sock *sk)
 227 {
 228         struct sk_buff *skb;
 229         struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
 230
 231         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 232                 kfree_skb(skb);
 233
 234         if (tunnel) {
 235                 l2tp_tunnel_closeall(tunnel);
 236                 sock_put(sk);
 237         }
 238
 239         sk_refcnt_debug_dec(sk);
 240 }
 241
 242 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 243 {
 244         struct inet_sock *inet = inet_sk(sk);
 245         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 246         struct net *net = sock_net(sk);
 247         int ret;
 248         int chk_addr_ret;
 249
 250         if (addr_len < sizeof(struct sockaddr_l2tpip))
 251                 return -EINVAL;
 252         if (addr->l2tp_family != AF_INET)
 253                 return -EINVAL;
 254
 255         lock_sock(sk);
 256
 257         ret = -EINVAL;
 258         if (!sock_flag(sk, SOCK_ZAPPED))
 259                 goto out;
 260
 261         if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
 262                 goto out;
 263
 264         chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
 265         ret = -EADDRNOTAVAIL;
 266         if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
 267             chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 268                 goto out;
 269
 270         if (addr->l2tp_addr.s_addr)
 271                 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
 272         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 273                 inet->inet_saddr = 0;  /* Use device */
 274
 275         write_lock_bh(&l2tp_ip_lock);
 276         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
 277                                   sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
 278                 write_unlock_bh(&l2tp_ip_lock);
 279                 ret = -EADDRINUSE;
 280                 goto out;
 281         }
 282
 283         sk_dst_reset(sk);
 284         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 285
 286         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 287         sk_del_node_init(sk);
 288         write_unlock_bh(&l2tp_ip_lock);
 289
 290         ret = 0;
 291         sock_reset_flag(sk, SOCK_ZAPPED);
 292
 293 out:
 294         release_sock(sk);
 295
 296         return ret;
 297 }
 298
 299 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 300 {
 301         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 302         int rc;
 303
 304         if (addr_len < sizeof(*lsa))
 305                 return -EINVAL;
 306
 307         if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 308                 return -EINVAL;
 309
 310         lock_sock(sk);
 311
 312         /* Must bind first - autobinding does not work */
 313         if (sock_flag(sk, SOCK_ZAPPED)) {
 314                 rc = -EINVAL;
 315                 goto out_sk;
 316         }
 317
 318         rc = __ip4_datagram_connect(sk, uaddr, addr_len);
 319         if (rc < 0)
 320                 goto out_sk;
 321
 322         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 323
 324         write_lock_bh(&l2tp_ip_lock);
 325         hlist_del_init(&sk->sk_bind_node);
 326         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 327         write_unlock_bh(&l2tp_ip_lock);
 328
 329 out_sk:
 330         release_sock(sk);
 331
 332         return rc;
 333 }
 334
 335 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 336 {
 337         if (sock_flag(sk, SOCK_ZAPPED))
 338                 return 0;
 339
 340         return __udp_disconnect(sk, flags);
 341 }
 342
 343 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 344                            int *uaddr_len, int peer)
 345 {
 346         struct sock *sk         = sock->sk;
 347         struct inet_sock *inet  = inet_sk(sk);
 348         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 349         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 350
 351         memset(lsa, 0, sizeof(*lsa));
 352         lsa->l2tp_family = AF_INET;
 353         if (peer) {
 354                 if (!inet->inet_dport)
 355                         return -ENOTCONN;
 356                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 357                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 358         } else {
 359                 __be32 addr = inet->inet_rcv_saddr;
 360                 if (!addr)
 361                         addr = inet->inet_saddr;
 362                 lsa->l2tp_conn_id = lsk->conn_id;
 363                 lsa->l2tp_addr.s_addr = addr;
 364         }
 365         *uaddr_len = sizeof(*lsa);
 366         return 0;
 367 }
 368
 369 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 370 {
 371         int rc;
 372
 373         /* Charge it to the socket, dropping if the queue is full. */
 374         rc = sock_queue_rcv_skb(sk, skb);
 375         if (rc < 0)
 376                 goto drop;
 377
 378         return 0;
 379
 380 drop:
 381         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 382         kfree_skb(skb);
 383         return -1;
 384 }
 385
 386 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 387  * control frames.
 388  */
 389 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 390 {
 391         struct sk_buff *skb;
 392         int rc;
 393         struct inet_sock *inet = inet_sk(sk);
 394         struct rtable *rt = NULL;
 395         struct flowi4 *fl4;
 396         int connected = 0;
 397         __be32 daddr;
 398
 399         lock_sock(sk);
 400
 401         rc = -ENOTCONN;
 402         if (sock_flag(sk, SOCK_DEAD))
 403                 goto out;
 404
 405         /* Get and verify the address. */
 406         if (msg->msg_name) {
 407                 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
 408                 rc = -EINVAL;
 409                 if (msg->msg_namelen < sizeof(*lip))
 410                         goto out;
 411
 412                 if (lip->l2tp_family != AF_INET) {
 413                         rc = -EAFNOSUPPORT;
 414                         if (lip->l2tp_family != AF_UNSPEC)
 415                                 goto out;
 416                 }
 417
 418                 daddr = lip->l2tp_addr.s_addr;
 419         } else {
 420                 rc = -EDESTADDRREQ;
 421                 if (sk->sk_state != TCP_ESTABLISHED)
 422                         goto out;
 423
 424                 daddr = inet->inet_daddr;
 425                 connected = 1;
 426         }
 427
 428         /* Allocate a socket buffer */
 429         rc = -ENOMEM;
 430         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 431                            4 + len, 0, GFP_KERNEL);
 432         if (!skb)
 433                 goto error;
 434
 435         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 436         skb_reserve(skb, 2 + NET_SKB_PAD);
 437         skb_reset_network_header(skb);
 438         skb_reserve(skb, sizeof(struct iphdr));
 439         skb_reset_transport_header(skb);
 440
 441         /* Insert 0 session_id */
 442         *((__be32 *) skb_put(skb, 4)) = 0;
 443
 444         /* Copy user data into skb */
 445         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 446         if (rc < 0) {
 447                 kfree_skb(skb);
 448                 goto error;
 449         }
 450
 451         fl4 = &inet->cork.fl.u.ip4;
 452         if (connected)
 453                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 454
 455         rcu_read_lock();
 456         if (rt == NULL) {
 457                 const struct ip_options_rcu *inet_opt;
 458
 459                 inet_opt = rcu_dereference(inet->inet_opt);
 460
 461                 /* Use correct destination address if we have options. */
 462                 if (inet_opt && inet_opt->opt.srr)
 463                         daddr = inet_opt->opt.faddr;
 464
 465                 /* If this fails, retransmit mechanism of transport layer will
 466                  * keep trying until route appears or the connection times
 467                  * itself out.
 468                  */
 469                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 470                                            daddr, inet->inet_saddr,
 471                                            inet->inet_dport, inet->inet_sport,
 472                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 473                                            sk->sk_bound_dev_if);
 474                 if (IS_ERR(rt))
 475                         goto no_route;
 476                 if (connected) {
 477                         sk_setup_caps(sk, &rt->dst);
 478                 } else {
 479                         skb_dst_set(skb, &rt->dst);
 480                         goto xmit;
 481                 }
 482         }
 483
 484         /* We dont need to clone dst here, it is guaranteed to not disappear.
 485          *  __dev_xmit_skb() might force a refcount if needed.
 486          */
 487         skb_dst_set_noref(skb, &rt->dst);
 488
 489 xmit:
 490         /* Queue the packet to IP for output */
 491         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 492         rcu_read_unlock();
 493
 494 error:
 495         if (rc >= 0)
 496                 rc = len;
 497
 498 out:
 499         release_sock(sk);
 500         return rc;
 501
 502 no_route:
 503         rcu_read_unlock();
 504         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 505         kfree_skb(skb);
 506         rc = -EHOSTUNREACH;
 507         goto out;
 508 }
 509
 510 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 511                            size_t len, int noblock, int flags, int *addr_len)
 512 {
 513         struct inet_sock *inet = inet_sk(sk);
 514         size_t copied = 0;
 515         int err = -EOPNOTSUPP;
 516         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 517         struct sk_buff *skb;
 518
 519         if (flags & MSG_OOB)
 520                 goto out;
 521
 522         skb = skb_recv_datagram(sk, flags, noblock, &err);
 523         if (!skb)
 524                 goto out;
 525
 526         copied = skb->len;
 527         if (len < copied) {
 528                 msg->msg_flags |= MSG_TRUNC;
 529                 copied = len;
 530         }
 531
 532         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 533         if (err)
 534                 goto done;
 535
 536         sock_recv_timestamp(msg, sk, skb);
 537
 538         /* Copy the address. */
 539         if (sin) {
 540                 sin->sin_family = AF_INET;
 541                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 542                 sin->sin_port = 0;
 543                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 544                 *addr_len = sizeof(*sin);
 545         }
 546         if (inet->cmsg_flags)
 547                 ip_cmsg_recv(msg, skb);
 548         if (flags & MSG_TRUNC)
 549                 copied = skb->len;
 550 done:
 551         skb_free_datagram(sk, skb);
 552 out:
 553         return err ? err : copied;
 554 }
 555
 556 static struct proto l2tp_ip_prot = {
 557         .name              = "L2TP/IP",
 558         .owner             = THIS_MODULE,
 559         .init              = l2tp_ip_open,
 560         .close             = l2tp_ip_close,
 561         .bind              = l2tp_ip_bind,
 562         .connect           = l2tp_ip_connect,
 563         .disconnect        = l2tp_ip_disconnect,
 564         .ioctl             = udp_ioctl,
 565         .destroy           = l2tp_ip_destroy_sock,
 566         .setsockopt        = ip_setsockopt,
 567         .getsockopt        = ip_getsockopt,
 568         .sendmsg           = l2tp_ip_sendmsg,
 569         .recvmsg           = l2tp_ip_recvmsg,
 570         .backlog_rcv       = l2tp_ip_backlog_recv,
 571         .hash              = inet_hash,
 572         .unhash            = inet_unhash,
 573         .obj_size          = sizeof(struct l2tp_ip_sock),
 574 #ifdef CONFIG_COMPAT
 575         .compat_setsockopt = compat_ip_setsockopt,
 576         .compat_getsockopt = compat_ip_getsockopt,
 577 #endif
 578 };
 579
 580 static const struct proto_ops l2tp_ip_ops = {
 581         .family            = PF_INET,
 582         .owner             = THIS_MODULE,
 583         .release           = inet_release,
 584         .bind              = inet_bind,
 585         .connect           = inet_dgram_connect,
 586         .socketpair        = sock_no_socketpair,
 587         .accept            = sock_no_accept,
 588         .getname           = l2tp_ip_getname,
 589         .poll              = datagram_poll,
 590         .ioctl             = inet_ioctl,
 591         .listen            = sock_no_listen,
 592         .shutdown          = inet_shutdown,
 593         .setsockopt        = sock_common_setsockopt,
 594         .getsockopt        = sock_common_getsockopt,
 595         .sendmsg           = inet_sendmsg,
 596         .recvmsg           = sock_common_recvmsg,
 597         .mmap              = sock_no_mmap,
 598         .sendpage          = sock_no_sendpage,
 599 #ifdef CONFIG_COMPAT
 600         .compat_setsockopt = compat_sock_common_setsockopt,
 601         .compat_getsockopt = compat_sock_common_getsockopt,
 602 #endif
 603 };
 604
 605 static struct inet_protosw l2tp_ip_protosw = {
 606         .type           = SOCK_DGRAM,
 607         .protocol       = IPPROTO_L2TP,
 608         .prot           = &l2tp_ip_prot,
 609         .ops            = &l2tp_ip_ops,
 610 };
 611
 612 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 613         .handler        = l2tp_ip_recv,
 614         .netns_ok       = 1,
 615 };
 616
 617 static int __init l2tp_ip_init(void)
 618 {
 619         int err;
 620
 621         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 622
 623         err = proto_register(&l2tp_ip_prot, 1);
 624         if (err != 0)
 625                 goto out;
 626
 627         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 628         if (err)
 629                 goto out1;
 630
 631         inet_register_protosw(&l2tp_ip_protosw);
 632         return 0;
 633
 634 out1:
 635         proto_unregister(&l2tp_ip_prot);
 636 out:
 637         return err;
 638 }
 639
 640 static void __exit l2tp_ip_exit(void)
 641 {
 642         inet_unregister_protosw(&l2tp_ip_protosw);
 643         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 644         proto_unregister(&l2tp_ip_prot);
 645 }
 646
 647 module_init(l2tp_ip_init);
 648 module_exit(l2tp_ip_exit);
 649
 650 MODULE_LICENSE("GPL");
 651 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 652 MODULE_DESCRIPTION("L2TP over IP");
 653 MODULE_VERSION("1.0");
 654
 655 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 656  * enums
 657  */
 658 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 659 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);