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(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
  51 {
  52         struct hlist_node *node;
  53         struct sock *sk;
  54
  55         sk_for_each_bound(sk, node, &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                     !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
  66                         goto found;
  67         }
  68
  69         sk = NULL;
  70 found:
  71         return sk;
  72 }
  73
  74 static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
  75 {
  76         struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
  77         if (sk)
  78                 sock_hold(sk);
  79
  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         /* Point to L2TP header */
 128         optr = ptr = skb->data;
 129
 130         if (!pskb_may_pull(skb, 4))
 131                 goto discard;
 132
 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                 pr_debug("%s: ip recv\n", tunnel->name);
 161                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 162         }
 163
 164         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
 165
 166         return 0;
 167
 168 pass_up:
 169         /* Get the tunnel_id from the L2TP header */
 170         if (!pskb_may_pull(skb, 12))
 171                 goto discard;
 172
 173         if ((skb->data[0] & 0xc0) != 0xc0)
 174                 goto discard;
 175
 176         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 177         tunnel = l2tp_tunnel_find(net, tunnel_id);
 178         if (tunnel != NULL)
 179                 sk = tunnel->sock;
 180         else {
 181                 struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
 182
 183                 read_lock_bh(&l2tp_ip_lock);
 184                 sk = __l2tp_ip_bind_lookup(net, iph->daddr, 0, tunnel_id);
 185                 read_unlock_bh(&l2tp_ip_lock);
 186         }
 187
 188         if (sk == NULL)
 189                 goto discard;
 190
 191         sock_hold(sk);
 192
 193         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 194                 goto discard_put;
 195
 196         nf_reset(skb);
 197
 198         return sk_receive_skb(sk, skb, 1);
 199
 200 discard_put:
 201         sock_put(sk);
 202
 203 discard:
 204         kfree_skb(skb);
 205         return 0;
 206 }
 207
 208 static int l2tp_ip_open(struct sock *sk)
 209 {
 210         /* Prevent autobind. We don't have ports. */
 211         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 212
 213         write_lock_bh(&l2tp_ip_lock);
 214         sk_add_node(sk, &l2tp_ip_table);
 215         write_unlock_bh(&l2tp_ip_lock);
 216
 217         return 0;
 218 }
 219
 220 static void l2tp_ip_close(struct sock *sk, long timeout)
 221 {
 222         write_lock_bh(&l2tp_ip_lock);
 223         hlist_del_init(&sk->sk_bind_node);
 224         sk_del_node_init(sk);
 225         write_unlock_bh(&l2tp_ip_lock);
 226         sk_common_release(sk);
 227 }
 228
 229 static void l2tp_ip_destroy_sock(struct sock *sk)
 230 {
 231         struct sk_buff *skb;
 232
 233         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 234                 kfree_skb(skb);
 235
 236         sk_refcnt_debug_dec(sk);
 237 }
 238
 239 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 240 {
 241         struct inet_sock *inet = inet_sk(sk);
 242         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 243         struct net *net = sock_net(sk);
 244         int ret;
 245         int chk_addr_ret;
 246
 247         if (!sock_flag(sk, SOCK_ZAPPED))
 248                 return -EINVAL;
 249         if (addr_len < sizeof(struct sockaddr_l2tpip))
 250                 return -EINVAL;
 251         if (addr->l2tp_family != AF_INET)
 252                 return -EINVAL;
 253
 254         ret = -EADDRINUSE;
 255         read_lock_bh(&l2tp_ip_lock);
 256         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr,
 257                                   sk->sk_bound_dev_if, addr->l2tp_conn_id))
 258                 goto out_in_use;
 259
 260         read_unlock_bh(&l2tp_ip_lock);
 261
 262         lock_sock(sk);
 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         sk_dst_reset(sk);
 277
 278         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 279
 280         write_lock_bh(&l2tp_ip_lock);
 281         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 282         sk_del_node_init(sk);
 283         write_unlock_bh(&l2tp_ip_lock);
 284         ret = 0;
 285         sock_reset_flag(sk, SOCK_ZAPPED);
 286
 287 out:
 288         release_sock(sk);
 289
 290         return ret;
 291
 292 out_in_use:
 293         read_unlock_bh(&l2tp_ip_lock);
 294
 295         return ret;
 296 }
 297
 298 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 299 {
 300         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 301         int rc;
 302
 303         if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
 304                 return -EINVAL;
 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         rc = ip4_datagram_connect(sk, uaddr, addr_len);
 313         if (rc < 0)
 314                 return rc;
 315
 316         lock_sock(sk);
 317
 318         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 319
 320         write_lock_bh(&l2tp_ip_lock);
 321         hlist_del_init(&sk->sk_bind_node);
 322         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 323         write_unlock_bh(&l2tp_ip_lock);
 324
 325         release_sock(sk);
 326         return rc;
 327 }
 328
 329 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 330 {
 331         if (sock_flag(sk, SOCK_ZAPPED))
 332                 return 0;
 333
 334         return udp_disconnect(sk, flags);
 335 }
 336
 337 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 338                            int *uaddr_len, int peer)
 339 {
 340         struct sock *sk         = sock->sk;
 341         struct inet_sock *inet  = inet_sk(sk);
 342         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 343         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 344
 345         memset(lsa, 0, sizeof(*lsa));
 346         lsa->l2tp_family = AF_INET;
 347         if (peer) {
 348                 if (!inet->inet_dport)
 349                         return -ENOTCONN;
 350                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 351                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 352         } else {
 353                 __be32 addr = inet->inet_rcv_saddr;
 354                 if (!addr)
 355                         addr = inet->inet_saddr;
 356                 lsa->l2tp_conn_id = lsk->conn_id;
 357                 lsa->l2tp_addr.s_addr = addr;
 358         }
 359         *uaddr_len = sizeof(*lsa);
 360         return 0;
 361 }
 362
 363 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 364 {
 365         int rc;
 366
 367         /* Charge it to the socket, dropping if the queue is full. */
 368         rc = sock_queue_rcv_skb(sk, skb);
 369         if (rc < 0)
 370                 goto drop;
 371
 372         return 0;
 373
 374 drop:
 375         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 376         kfree_skb(skb);
 377         return -1;
 378 }
 379
 380 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 381  * control frames.
 382  */
 383 static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len)
 384 {
 385         struct sk_buff *skb;
 386         int rc;
 387         struct inet_sock *inet = inet_sk(sk);
 388         struct rtable *rt = NULL;
 389         struct flowi4 *fl4;
 390         int connected = 0;
 391         __be32 daddr;
 392
 393         lock_sock(sk);
 394
 395         rc = -ENOTCONN;
 396         if (sock_flag(sk, SOCK_DEAD))
 397                 goto out;
 398
 399         /* Get and verify the address. */
 400         if (msg->msg_name) {
 401                 struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name;
 402                 rc = -EINVAL;
 403                 if (msg->msg_namelen < sizeof(*lip))
 404                         goto out;
 405
 406                 if (lip->l2tp_family != AF_INET) {
 407                         rc = -EAFNOSUPPORT;
 408                         if (lip->l2tp_family != AF_UNSPEC)
 409                                 goto out;
 410                 }
 411
 412                 daddr = lip->l2tp_addr.s_addr;
 413         } else {
 414                 rc = -EDESTADDRREQ;
 415                 if (sk->sk_state != TCP_ESTABLISHED)
 416                         goto out;
 417
 418                 daddr = inet->inet_daddr;
 419                 connected = 1;
 420         }
 421
 422         /* Allocate a socket buffer */
 423         rc = -ENOMEM;
 424         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 425                            4 + len, 0, GFP_KERNEL);
 426         if (!skb)
 427                 goto error;
 428
 429         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 430         skb_reserve(skb, 2 + NET_SKB_PAD);
 431         skb_reset_network_header(skb);
 432         skb_reserve(skb, sizeof(struct iphdr));
 433         skb_reset_transport_header(skb);
 434
 435         /* Insert 0 session_id */
 436         *((__be32 *) skb_put(skb, 4)) = 0;
 437
 438         /* Copy user data into skb */
 439         rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
 440         if (rc < 0) {
 441                 kfree_skb(skb);
 442                 goto error;
 443         }
 444
 445         fl4 = &inet->cork.fl.u.ip4;
 446         if (connected)
 447                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 448
 449         rcu_read_lock();
 450         if (rt == NULL) {
 451                 const struct ip_options_rcu *inet_opt;
 452
 453                 inet_opt = rcu_dereference(inet->inet_opt);
 454
 455                 /* Use correct destination address if we have options. */
 456                 if (inet_opt && inet_opt->opt.srr)
 457                         daddr = inet_opt->opt.faddr;
 458
 459                 /* If this fails, retransmit mechanism of transport layer will
 460                  * keep trying until route appears or the connection times
 461                  * itself out.
 462                  */
 463                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 464                                            daddr, inet->inet_saddr,
 465                                            inet->inet_dport, inet->inet_sport,
 466                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 467                                            sk->sk_bound_dev_if);
 468                 if (IS_ERR(rt))
 469                         goto no_route;
 470                 if (connected) {
 471                         sk_setup_caps(sk, &rt->dst);
 472                 } else {
 473                         skb_dst_set(skb, &rt->dst);
 474                         goto xmit;
 475                 }
 476         }
 477
 478         /* We dont need to clone dst here, it is guaranteed to not disappear.
 479          *  __dev_xmit_skb() might force a refcount if needed.
 480          */
 481         skb_dst_set_noref(skb, &rt->dst);
 482
 483 xmit:
 484         /* Queue the packet to IP for output */
 485         rc = ip_queue_xmit(skb, &inet->cork.fl);
 486         rcu_read_unlock();
 487
 488 error:
 489         if (rc >= 0)
 490                 rc = len;
 491
 492 out:
 493         release_sock(sk);
 494         return rc;
 495
 496 no_route:
 497         rcu_read_unlock();
 498         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 499         kfree_skb(skb);
 500         rc = -EHOSTUNREACH;
 501         goto out;
 502 }
 503
 504 static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 505                            size_t len, int noblock, int flags, int *addr_len)
 506 {
 507         struct inet_sock *inet = inet_sk(sk);
 508         size_t copied = 0;
 509         int err = -EOPNOTSUPP;
 510         struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
 511         struct sk_buff *skb;
 512
 513         if (flags & MSG_OOB)
 514                 goto out;
 515
 516         if (addr_len)
 517                 *addr_len = sizeof(*sin);
 518
 519         skb = skb_recv_datagram(sk, flags, noblock, &err);
 520         if (!skb)
 521                 goto out;
 522
 523         copied = skb->len;
 524         if (len < copied) {
 525                 msg->msg_flags |= MSG_TRUNC;
 526                 copied = len;
 527         }
 528
 529         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
 530         if (err)
 531                 goto done;
 532
 533         sock_recv_timestamp(msg, sk, skb);
 534
 535         /* Copy the address. */
 536         if (sin) {
 537                 sin->sin_family = AF_INET;
 538                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 539                 sin->sin_port = 0;
 540                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 541         }
 542         if (inet->cmsg_flags)
 543                 ip_cmsg_recv(msg, skb);
 544         if (flags & MSG_TRUNC)
 545                 copied = skb->len;
 546 done:
 547         skb_free_datagram(sk, skb);
 548 out:
 549         return err ? err : copied;
 550 }
 551
 552 static struct proto l2tp_ip_prot = {
 553         .name              = "L2TP/IP",
 554         .owner             = THIS_MODULE,
 555         .init              = l2tp_ip_open,
 556         .close             = l2tp_ip_close,
 557         .bind              = l2tp_ip_bind,
 558         .connect           = l2tp_ip_connect,
 559         .disconnect        = l2tp_ip_disconnect,
 560         .ioctl             = udp_ioctl,
 561         .destroy           = l2tp_ip_destroy_sock,
 562         .setsockopt        = ip_setsockopt,
 563         .getsockopt        = ip_getsockopt,
 564         .sendmsg           = l2tp_ip_sendmsg,
 565         .recvmsg           = l2tp_ip_recvmsg,
 566         .backlog_rcv       = l2tp_ip_backlog_recv,
 567         .hash              = inet_hash,
 568         .unhash            = inet_unhash,
 569         .obj_size          = sizeof(struct l2tp_ip_sock),
 570 #ifdef CONFIG_COMPAT
 571         .compat_setsockopt = compat_ip_setsockopt,
 572         .compat_getsockopt = compat_ip_getsockopt,
 573 #endif
 574 };
 575
 576 static const struct proto_ops l2tp_ip_ops = {
 577         .family            = PF_INET,
 578         .owner             = THIS_MODULE,
 579         .release           = inet_release,
 580         .bind              = inet_bind,
 581         .connect           = inet_dgram_connect,
 582         .socketpair        = sock_no_socketpair,
 583         .accept            = sock_no_accept,
 584         .getname           = l2tp_ip_getname,
 585         .poll              = datagram_poll,
 586         .ioctl             = inet_ioctl,
 587         .listen            = sock_no_listen,
 588         .shutdown          = inet_shutdown,
 589         .setsockopt        = sock_common_setsockopt,
 590         .getsockopt        = sock_common_getsockopt,
 591         .sendmsg           = inet_sendmsg,
 592         .recvmsg           = sock_common_recvmsg,
 593         .mmap              = sock_no_mmap,
 594         .sendpage          = sock_no_sendpage,
 595 #ifdef CONFIG_COMPAT
 596         .compat_setsockopt = compat_sock_common_setsockopt,
 597         .compat_getsockopt = compat_sock_common_getsockopt,
 598 #endif
 599 };
 600
 601 static struct inet_protosw l2tp_ip_protosw = {
 602         .type           = SOCK_DGRAM,
 603         .protocol       = IPPROTO_L2TP,
 604         .prot           = &l2tp_ip_prot,
 605         .ops            = &l2tp_ip_ops,
 606         .no_check       = 0,
 607 };
 608
 609 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 610         .handler        = l2tp_ip_recv,
 611         .netns_ok       = 1,
 612 };
 613
 614 static int __init l2tp_ip_init(void)
 615 {
 616         int err;
 617
 618         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 619
 620         err = proto_register(&l2tp_ip_prot, 1);
 621         if (err != 0)
 622                 goto out;
 623
 624         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 625         if (err)
 626                 goto out1;
 627
 628         inet_register_protosw(&l2tp_ip_protosw);
 629         return 0;
 630
 631 out1:
 632         proto_unregister(&l2tp_ip_prot);
 633 out:
 634         return err;
 635 }
 636
 637 static void __exit l2tp_ip_exit(void)
 638 {
 639         inet_unregister_protosw(&l2tp_ip_protosw);
 640         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 641         proto_unregister(&l2tp_ip_prot);
 642 }
 643
 644 module_init(l2tp_ip_init);
 645 module_exit(l2tp_ip_exit);
 646
 647 MODULE_LICENSE("GPL");
 648 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 649 MODULE_DESCRIPTION("L2TP over IP");
 650 MODULE_VERSION("1.0");
 651
 652 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 653  * enums
 654  */
 655 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);