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         struct iphdr *iph;
 127         int length;
 128
 129         if (!pskb_may_pull(skb, 4))
 130                 goto discard;
 131
 132         /* Point to L2TP header */
 133         optr = ptr = skb->data;
 134         session_id = ntohl(*((__be32 *) ptr));
 135         ptr += 4;
 136
 137         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 138          * the session_id. If it is 0, the packet is a L2TP control
 139          * frame and the session_id value can be discarded.
 140          */
 141         if (session_id == 0) {
 142                 __skb_pull(skb, 4);
 143                 goto pass_up;
 144         }
 145
 146         /* Ok, this is a data packet. Lookup the session. */
 147         session = l2tp_session_get(net, session_id);
 148         if (!session)
 149                 goto discard;
 150
 151         tunnel = session->tunnel;
 152         if (!tunnel)
 153                 goto discard_sess;
 154
 155         /* Trace packet contents, if enabled */
 156         if (tunnel->debug & L2TP_MSG_DATA) {
 157                 length = min(32u, skb->len);
 158                 if (!pskb_may_pull(skb, length))
 159                         goto discard_sess;
 160
 161                 /* Point to L2TP header */
 162                 optr = ptr = skb->data;
 163                 ptr += 4;
 164                 pr_debug("%s: ip recv\n", tunnel->name);
 165                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 166         }
 167
 168         if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
 169                 goto discard_sess;
 170
 171         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
 172         l2tp_session_dec_refcount(session);
 173
 174         return 0;
 175
 176 pass_up:
 177         /* Get the tunnel_id from the L2TP header */
 178         if (!pskb_may_pull(skb, 12))
 179                 goto discard;
 180
 181         if ((skb->data[0] & 0xc0) != 0xc0)
 182                 goto discard;
 183
 184         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 185         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, inet_iif(skb),
 189                                    tunnel_id);
 190         if (!sk) {
 191                 read_unlock_bh(&l2tp_ip_lock);
 192                 goto discard;
 193         }
 194         sock_hold(sk);
 195         read_unlock_bh(&l2tp_ip_lock);
 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_sess:
 205         l2tp_session_dec_refcount(session);
 206         goto discard;
 207
 208 discard_put:
 209         sock_put(sk);
 210
 211 discard:
 212         kfree_skb(skb);
 213         return 0;
 214 }
 215
 216 static int l2tp_ip_open(struct sock *sk)
 217 {
 218         /* Prevent autobind. We don't have ports. */
 219         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 220
 221         write_lock_bh(&l2tp_ip_lock);
 222         sk_add_node(sk, &l2tp_ip_table);
 223         write_unlock_bh(&l2tp_ip_lock);
 224
 225         return 0;
 226 }
 227
 228 static void l2tp_ip_close(struct sock *sk, long timeout)
 229 {
 230         write_lock_bh(&l2tp_ip_lock);
 231         hlist_del_init(&sk->sk_bind_node);
 232         sk_del_node_init(sk);
 233         write_unlock_bh(&l2tp_ip_lock);
 234         sk_common_release(sk);
 235 }
 236
 237 static void l2tp_ip_destroy_sock(struct sock *sk)
 238 {
 239         struct sk_buff *skb;
 240         struct l2tp_tunnel *tunnel = sk->sk_user_data;
 241
 242         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 243                 kfree_skb(skb);
 244
 245         if (tunnel)
 246                 l2tp_tunnel_delete(tunnel);
 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 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         return sizeof(*lsa);
 373 }
 374
 375 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 376 {
 377         int rc;
 378
 379         /* Charge it to the socket, dropping if the queue is full. */
 380         rc = sock_queue_rcv_skb(sk, skb);
 381         if (rc < 0)
 382                 goto drop;
 383
 384         return 0;
 385
 386 drop:
 387         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 388         kfree_skb(skb);
 389         return 0;
 390 }
 391
 392 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 393  * control frames.
 394  */
 395 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 396 {
 397         struct sk_buff *skb;
 398         int rc;
 399         struct inet_sock *inet = inet_sk(sk);
 400         struct rtable *rt = NULL;
 401         struct flowi4 *fl4;
 402         int connected = 0;
 403         __be32 daddr;
 404
 405         lock_sock(sk);
 406
 407         rc = -ENOTCONN;
 408         if (sock_flag(sk, SOCK_DEAD))
 409                 goto out;
 410
 411         /* Get and verify the address. */
 412         if (msg->msg_name) {
 413                 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
 414                 rc = -EINVAL;
 415                 if (msg->msg_namelen < sizeof(*lip))
 416                         goto out;
 417
 418                 if (lip->l2tp_family != AF_INET) {
 419                         rc = -EAFNOSUPPORT;
 420                         if (lip->l2tp_family != AF_UNSPEC)
 421                                 goto out;
 422                 }
 423
 424                 daddr = lip->l2tp_addr.s_addr;
 425         } else {
 426                 rc = -EDESTADDRREQ;
 427                 if (sk->sk_state != TCP_ESTABLISHED)
 428                         goto out;
 429
 430                 daddr = inet->inet_daddr;
 431                 connected = 1;
 432         }
 433
 434         /* Allocate a socket buffer */
 435         rc = -ENOMEM;
 436         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 437                            4 + len, 0, GFP_KERNEL);
 438         if (!skb)
 439                 goto error;
 440
 441         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 442         skb_reserve(skb, 2 + NET_SKB_PAD);
 443         skb_reset_network_header(skb);
 444         skb_reserve(skb, sizeof(struct iphdr));
 445         skb_reset_transport_header(skb);
 446
 447         /* Insert 0 session_id */
 448         *((__be32 *) skb_put(skb, 4)) = 0;
 449
 450         /* Copy user data into skb */
 451         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 452         if (rc < 0) {
 453                 kfree_skb(skb);
 454                 goto error;
 455         }
 456
 457         fl4 = &inet->cork.fl.u.ip4;
 458         if (connected)
 459                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 460
 461         rcu_read_lock();
 462         if (rt == NULL) {
 463                 const struct ip_options_rcu *inet_opt;
 464
 465                 inet_opt = rcu_dereference(inet->inet_opt);
 466
 467                 /* Use correct destination address if we have options. */
 468                 if (inet_opt && inet_opt->opt.srr)
 469                         daddr = inet_opt->opt.faddr;
 470
 471                 /* If this fails, retransmit mechanism of transport layer will
 472                  * keep trying until route appears or the connection times
 473                  * itself out.
 474                  */
 475                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 476                                            daddr, inet->inet_saddr,
 477                                            inet->inet_dport, inet->inet_sport,
 478                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 479                                            sk->sk_bound_dev_if);
 480                 if (IS_ERR(rt))
 481                         goto no_route;
 482                 if (connected) {
 483                         sk_setup_caps(sk, &rt->dst);
 484                 } else {
 485                         skb_dst_set(skb, &rt->dst);
 486                         goto xmit;
 487                 }
 488         }
 489
 490         /* We dont need to clone dst here, it is guaranteed to not disappear.
 491          *  __dev_xmit_skb() might force a refcount if needed.
 492          */
 493         skb_dst_set_noref(skb, &rt->dst);
 494
 495 xmit:
 496         /* Queue the packet to IP for output */
 497         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 498         rcu_read_unlock();
 499
 500 error:
 501         if (rc >= 0)
 502                 rc = len;
 503
 504 out:
 505         release_sock(sk);
 506         return rc;
 507
 508 no_route:
 509         rcu_read_unlock();
 510         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 511         kfree_skb(skb);
 512         rc = -EHOSTUNREACH;
 513         goto out;
 514 }
 515
 516 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 517                            size_t len, int noblock, int flags, int *addr_len)
 518 {
 519         struct inet_sock *inet = inet_sk(sk);
 520         size_t copied = 0;
 521         int err = -EOPNOTSUPP;
 522         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 523         struct sk_buff *skb;
 524
 525         if (flags & MSG_OOB)
 526                 goto out;
 527
 528         skb = skb_recv_datagram(sk, flags, noblock, &err);
 529         if (!skb)
 530                 goto out;
 531
 532         copied = skb->len;
 533         if (len < copied) {
 534                 msg->msg_flags |= MSG_TRUNC;
 535                 copied = len;
 536         }
 537
 538         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 539         if (err)
 540                 goto done;
 541
 542         sock_recv_timestamp(msg, sk, skb);
 543
 544         /* Copy the address. */
 545         if (sin) {
 546                 sin->sin_family = AF_INET;
 547                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 548                 sin->sin_port = 0;
 549                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 550                 *addr_len = sizeof(*sin);
 551         }
 552         if (inet->cmsg_flags)
 553                 ip_cmsg_recv(msg, skb);
 554         if (flags & MSG_TRUNC)
 555                 copied = skb->len;
 556 done:
 557         skb_free_datagram(sk, skb);
 558 out:
 559         return err ? err : copied;
 560 }
 561
 562 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 563 {
 564         struct sk_buff *skb;
 565         int amount;
 566
 567         switch (cmd) {
 568         case SIOCOUTQ:
 569                 amount = sk_wmem_alloc_get(sk);
 570                 break;
 571         case SIOCINQ:
 572                 spin_lock_bh(&sk->sk_receive_queue.lock);
 573                 skb = skb_peek(&sk->sk_receive_queue);
 574                 amount = skb ? skb->len : 0;
 575                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 576                 break;
 577
 578         default:
 579                 return -ENOIOCTLCMD;
 580         }
 581
 582         return put_user(amount, (int __user *)arg);
 583 }
 584 EXPORT_SYMBOL(l2tp_ioctl);
 585
 586 static struct proto l2tp_ip_prot = {
 587         .name              = "L2TP/IP",
 588         .owner             = THIS_MODULE,
 589         .init              = l2tp_ip_open,
 590         .close             = l2tp_ip_close,
 591         .bind              = l2tp_ip_bind,
 592         .connect           = l2tp_ip_connect,
 593         .disconnect        = l2tp_ip_disconnect,
 594         .ioctl             = l2tp_ioctl,
 595         .destroy           = l2tp_ip_destroy_sock,
 596         .setsockopt        = ip_setsockopt,
 597         .getsockopt        = ip_getsockopt,
 598         .sendmsg           = l2tp_ip_sendmsg,
 599         .recvmsg           = l2tp_ip_recvmsg,
 600         .backlog_rcv       = l2tp_ip_backlog_recv,
 601         .hash              = inet_hash,
 602         .unhash            = inet_unhash,
 603         .obj_size          = sizeof(struct l2tp_ip_sock),
 604 #ifdef CONFIG_COMPAT
 605         .compat_setsockopt = compat_ip_setsockopt,
 606         .compat_getsockopt = compat_ip_getsockopt,
 607 #endif
 608 };
 609
 610 static const struct proto_ops l2tp_ip_ops = {
 611         .family            = PF_INET,
 612         .owner             = THIS_MODULE,
 613         .release           = inet_release,
 614         .bind              = inet_bind,
 615         .connect           = inet_dgram_connect,
 616         .socketpair        = sock_no_socketpair,
 617         .accept            = sock_no_accept,
 618         .getname           = l2tp_ip_getname,
 619         .poll              = datagram_poll,
 620         .ioctl             = inet_ioctl,
 621         .listen            = sock_no_listen,
 622         .shutdown          = inet_shutdown,
 623         .setsockopt        = sock_common_setsockopt,
 624         .getsockopt        = sock_common_getsockopt,
 625         .sendmsg           = inet_sendmsg,
 626         .recvmsg           = sock_common_recvmsg,
 627         .mmap              = sock_no_mmap,
 628         .sendpage          = sock_no_sendpage,
 629 #ifdef CONFIG_COMPAT
 630         .compat_setsockopt = compat_sock_common_setsockopt,
 631         .compat_getsockopt = compat_sock_common_getsockopt,
 632 #endif
 633 };
 634
 635 static struct inet_protosw l2tp_ip_protosw = {
 636         .type           = SOCK_DGRAM,
 637         .protocol       = IPPROTO_L2TP,
 638         .prot           = &l2tp_ip_prot,
 639         .ops            = &l2tp_ip_ops,
 640 };
 641
 642 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 643         .handler        = l2tp_ip_recv,
 644         .netns_ok       = 1,
 645 };
 646
 647 static int __init l2tp_ip_init(void)
 648 {
 649         int err;
 650
 651         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 652
 653         err = proto_register(&l2tp_ip_prot, 1);
 654         if (err != 0)
 655                 goto out;
 656
 657         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 658         if (err)
 659                 goto out1;
 660
 661         inet_register_protosw(&l2tp_ip_protosw);
 662         return 0;
 663
 664 out1:
 665         proto_unregister(&l2tp_ip_prot);
 666 out:
 667         return err;
 668 }
 669
 670 static void __exit l2tp_ip_exit(void)
 671 {
 672         inet_unregister_protosw(&l2tp_ip_protosw);
 673         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 674         proto_unregister(&l2tp_ip_prot);
 675 }
 676
 677 module_init(l2tp_ip_init);
 678 module_exit(l2tp_ip_exit);
 679
 680 MODULE_LICENSE("GPL");
 681 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 682 MODULE_DESCRIPTION("L2TP over IP");
 683 MODULE_VERSION("1.0");
 684
 685 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 686  * enums
 687  */
 688 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 689 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);