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         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
 169         l2tp_session_dec_refcount(session);
 170
 171         return 0;
 172
 173 pass_up:
 174         /* Get the tunnel_id from the L2TP header */
 175         if (!pskb_may_pull(skb, 12))
 176                 goto discard;
 177
 178         if ((skb->data[0] & 0xc0) != 0xc0)
 179                 goto discard;
 180
 181         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 182         iph = (struct iphdr *)skb_network_header(skb);
 183
 184         read_lock_bh(&l2tp_ip_lock);
 185         sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb),
 186                                    tunnel_id);
 187         if (!sk) {
 188                 read_unlock_bh(&l2tp_ip_lock);
 189                 goto discard;
 190         }
 191         sock_hold(sk);
 192         read_unlock_bh(&l2tp_ip_lock);
 193
 194         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 195                 goto discard_put;
 196
 197         nf_reset(skb);
 198
 199         return sk_receive_skb(sk, skb, 1);
 200
 201 discard_sess:
 202         l2tp_session_dec_refcount(session);
 203         goto discard;
 204
 205 discard_put:
 206         sock_put(sk);
 207
 208 discard:
 209         kfree_skb(skb);
 210         return 0;
 211 }
 212
 213 static int l2tp_ip_open(struct sock *sk)
 214 {
 215         /* Prevent autobind. We don't have ports. */
 216         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 217
 218         write_lock_bh(&l2tp_ip_lock);
 219         sk_add_node(sk, &l2tp_ip_table);
 220         write_unlock_bh(&l2tp_ip_lock);
 221
 222         return 0;
 223 }
 224
 225 static void l2tp_ip_close(struct sock *sk, long timeout)
 226 {
 227         write_lock_bh(&l2tp_ip_lock);
 228         hlist_del_init(&sk->sk_bind_node);
 229         sk_del_node_init(sk);
 230         write_unlock_bh(&l2tp_ip_lock);
 231         sk_common_release(sk);
 232 }
 233
 234 static void l2tp_ip_destroy_sock(struct sock *sk)
 235 {
 236         struct sk_buff *skb;
 237         struct l2tp_tunnel *tunnel = sk->sk_user_data;
 238
 239         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 240                 kfree_skb(skb);
 241
 242         if (tunnel)
 243                 l2tp_tunnel_delete(tunnel);
 244 }
 245
 246 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 247 {
 248         struct inet_sock *inet = inet_sk(sk);
 249         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 250         struct net *net = sock_net(sk);
 251         int ret;
 252         int chk_addr_ret;
 253
 254         if (addr_len < sizeof(struct sockaddr_l2tpip))
 255                 return -EINVAL;
 256         if (addr->l2tp_family != AF_INET)
 257                 return -EINVAL;
 258
 259         lock_sock(sk);
 260
 261         ret = -EINVAL;
 262         if (!sock_flag(sk, SOCK_ZAPPED))
 263                 goto out;
 264
 265         if (sk->sk_state != TCP_CLOSE)
 266                 goto out;
 267
 268         chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
 269         ret = -EADDRNOTAVAIL;
 270         if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
 271             chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 272                 goto out;
 273
 274         if (addr->l2tp_addr.s_addr)
 275                 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
 276         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 277                 inet->inet_saddr = 0;  /* Use device */
 278
 279         write_lock_bh(&l2tp_ip_lock);
 280         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
 281                                   sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
 282                 write_unlock_bh(&l2tp_ip_lock);
 283                 ret = -EADDRINUSE;
 284                 goto out;
 285         }
 286
 287         sk_dst_reset(sk);
 288         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 289
 290         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 291         sk_del_node_init(sk);
 292         write_unlock_bh(&l2tp_ip_lock);
 293
 294         ret = 0;
 295         sock_reset_flag(sk, SOCK_ZAPPED);
 296
 297 out:
 298         release_sock(sk);
 299
 300         return ret;
 301 }
 302
 303 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 304 {
 305         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 306         int rc;
 307
 308         if (addr_len < sizeof(*lsa))
 309                 return -EINVAL;
 310
 311         if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 312                 return -EINVAL;
 313
 314         lock_sock(sk);
 315
 316         /* Must bind first - autobinding does not work */
 317         if (sock_flag(sk, SOCK_ZAPPED)) {
 318                 rc = -EINVAL;
 319                 goto out_sk;
 320         }
 321
 322         rc = __ip4_datagram_connect(sk, uaddr, addr_len);
 323         if (rc < 0)
 324                 goto out_sk;
 325
 326         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 327
 328         write_lock_bh(&l2tp_ip_lock);
 329         hlist_del_init(&sk->sk_bind_node);
 330         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 331         write_unlock_bh(&l2tp_ip_lock);
 332
 333 out_sk:
 334         release_sock(sk);
 335
 336         return rc;
 337 }
 338
 339 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 340 {
 341         if (sock_flag(sk, SOCK_ZAPPED))
 342                 return 0;
 343
 344         return __udp_disconnect(sk, flags);
 345 }
 346
 347 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 348                            int peer)
 349 {
 350         struct sock *sk         = sock->sk;
 351         struct inet_sock *inet  = inet_sk(sk);
 352         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 353         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 354
 355         memset(lsa, 0, sizeof(*lsa));
 356         lsa->l2tp_family = AF_INET;
 357         if (peer) {
 358                 if (!inet->inet_dport)
 359                         return -ENOTCONN;
 360                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 361                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 362         } else {
 363                 __be32 addr = inet->inet_rcv_saddr;
 364                 if (!addr)
 365                         addr = inet->inet_saddr;
 366                 lsa->l2tp_conn_id = lsk->conn_id;
 367                 lsa->l2tp_addr.s_addr = addr;
 368         }
 369         return sizeof(*lsa);
 370 }
 371
 372 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 373 {
 374         int rc;
 375
 376         /* Charge it to the socket, dropping if the queue is full. */
 377         rc = sock_queue_rcv_skb(sk, skb);
 378         if (rc < 0)
 379                 goto drop;
 380
 381         return 0;
 382
 383 drop:
 384         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 385         kfree_skb(skb);
 386         return 0;
 387 }
 388
 389 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 390  * control frames.
 391  */
 392 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 393 {
 394         struct sk_buff *skb;
 395         int rc;
 396         struct inet_sock *inet = inet_sk(sk);
 397         struct rtable *rt = NULL;
 398         struct flowi4 *fl4;
 399         int connected = 0;
 400         __be32 daddr;
 401
 402         lock_sock(sk);
 403
 404         rc = -ENOTCONN;
 405         if (sock_flag(sk, SOCK_DEAD))
 406                 goto out;
 407
 408         /* Get and verify the address. */
 409         if (msg->msg_name) {
 410                 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
 411                 rc = -EINVAL;
 412                 if (msg->msg_namelen < sizeof(*lip))
 413                         goto out;
 414
 415                 if (lip->l2tp_family != AF_INET) {
 416                         rc = -EAFNOSUPPORT;
 417                         if (lip->l2tp_family != AF_UNSPEC)
 418                                 goto out;
 419                 }
 420
 421                 daddr = lip->l2tp_addr.s_addr;
 422         } else {
 423                 rc = -EDESTADDRREQ;
 424                 if (sk->sk_state != TCP_ESTABLISHED)
 425                         goto out;
 426
 427                 daddr = inet->inet_daddr;
 428                 connected = 1;
 429         }
 430
 431         /* Allocate a socket buffer */
 432         rc = -ENOMEM;
 433         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 434                            4 + len, 0, GFP_KERNEL);
 435         if (!skb)
 436                 goto error;
 437
 438         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 439         skb_reserve(skb, 2 + NET_SKB_PAD);
 440         skb_reset_network_header(skb);
 441         skb_reserve(skb, sizeof(struct iphdr));
 442         skb_reset_transport_header(skb);
 443
 444         /* Insert 0 session_id */
 445         *((__be32 *) skb_put(skb, 4)) = 0;
 446
 447         /* Copy user data into skb */
 448         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 449         if (rc < 0) {
 450                 kfree_skb(skb);
 451                 goto error;
 452         }
 453
 454         fl4 = &inet->cork.fl.u.ip4;
 455         if (connected)
 456                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 457
 458         rcu_read_lock();
 459         if (rt == NULL) {
 460                 const struct ip_options_rcu *inet_opt;
 461
 462                 inet_opt = rcu_dereference(inet->inet_opt);
 463
 464                 /* Use correct destination address if we have options. */
 465                 if (inet_opt && inet_opt->opt.srr)
 466                         daddr = inet_opt->opt.faddr;
 467
 468                 /* If this fails, retransmit mechanism of transport layer will
 469                  * keep trying until route appears or the connection times
 470                  * itself out.
 471                  */
 472                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 473                                            daddr, inet->inet_saddr,
 474                                            inet->inet_dport, inet->inet_sport,
 475                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 476                                            sk->sk_bound_dev_if);
 477                 if (IS_ERR(rt))
 478                         goto no_route;
 479                 if (connected) {
 480                         sk_setup_caps(sk, &rt->dst);
 481                 } else {
 482                         skb_dst_set(skb, &rt->dst);
 483                         goto xmit;
 484                 }
 485         }
 486
 487         /* We dont need to clone dst here, it is guaranteed to not disappear.
 488          *  __dev_xmit_skb() might force a refcount if needed.
 489          */
 490         skb_dst_set_noref(skb, &rt->dst);
 491
 492 xmit:
 493         /* Queue the packet to IP for output */
 494         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 495         rcu_read_unlock();
 496
 497 error:
 498         if (rc >= 0)
 499                 rc = len;
 500
 501 out:
 502         release_sock(sk);
 503         return rc;
 504
 505 no_route:
 506         rcu_read_unlock();
 507         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 508         kfree_skb(skb);
 509         rc = -EHOSTUNREACH;
 510         goto out;
 511 }
 512
 513 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 514                            size_t len, int noblock, int flags, int *addr_len)
 515 {
 516         struct inet_sock *inet = inet_sk(sk);
 517         size_t copied = 0;
 518         int err = -EOPNOTSUPP;
 519         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 520         struct sk_buff *skb;
 521
 522         if (flags & MSG_OOB)
 523                 goto out;
 524
 525         skb = skb_recv_datagram(sk, flags, noblock, &err);
 526         if (!skb)
 527                 goto out;
 528
 529         copied = skb->len;
 530         if (len < copied) {
 531                 msg->msg_flags |= MSG_TRUNC;
 532                 copied = len;
 533         }
 534
 535         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 536         if (err)
 537                 goto done;
 538
 539         sock_recv_timestamp(msg, sk, skb);
 540
 541         /* Copy the address. */
 542         if (sin) {
 543                 sin->sin_family = AF_INET;
 544                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 545                 sin->sin_port = 0;
 546                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 547                 *addr_len = sizeof(*sin);
 548         }
 549         if (inet->cmsg_flags)
 550                 ip_cmsg_recv(msg, skb);
 551         if (flags & MSG_TRUNC)
 552                 copied = skb->len;
 553 done:
 554         skb_free_datagram(sk, skb);
 555 out:
 556         return err ? err : copied;
 557 }
 558
 559 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 560 {
 561         struct sk_buff *skb;
 562         int amount;
 563
 564         switch (cmd) {
 565         case SIOCOUTQ:
 566                 amount = sk_wmem_alloc_get(sk);
 567                 break;
 568         case SIOCINQ:
 569                 spin_lock_bh(&sk->sk_receive_queue.lock);
 570                 skb = skb_peek(&sk->sk_receive_queue);
 571                 amount = skb ? skb->len : 0;
 572                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 573                 break;
 574
 575         default:
 576                 return -ENOIOCTLCMD;
 577         }
 578
 579         return put_user(amount, (int __user *)arg);
 580 }
 581 EXPORT_SYMBOL(l2tp_ioctl);
 582
 583 static struct proto l2tp_ip_prot = {
 584         .name              = "L2TP/IP",
 585         .owner             = THIS_MODULE,
 586         .init              = l2tp_ip_open,
 587         .close             = l2tp_ip_close,
 588         .bind              = l2tp_ip_bind,
 589         .connect           = l2tp_ip_connect,
 590         .disconnect        = l2tp_ip_disconnect,
 591         .ioctl             = l2tp_ioctl,
 592         .destroy           = l2tp_ip_destroy_sock,
 593         .setsockopt        = ip_setsockopt,
 594         .getsockopt        = ip_getsockopt,
 595         .sendmsg           = l2tp_ip_sendmsg,
 596         .recvmsg           = l2tp_ip_recvmsg,
 597         .backlog_rcv       = l2tp_ip_backlog_recv,
 598         .hash              = inet_hash,
 599         .unhash            = inet_unhash,
 600         .obj_size          = sizeof(struct l2tp_ip_sock),
 601 #ifdef CONFIG_COMPAT
 602         .compat_setsockopt = compat_ip_setsockopt,
 603         .compat_getsockopt = compat_ip_getsockopt,
 604 #endif
 605 };
 606
 607 static const struct proto_ops l2tp_ip_ops = {
 608         .family            = PF_INET,
 609         .owner             = THIS_MODULE,
 610         .release           = inet_release,
 611         .bind              = inet_bind,
 612         .connect           = inet_dgram_connect,
 613         .socketpair        = sock_no_socketpair,
 614         .accept            = sock_no_accept,
 615         .getname           = l2tp_ip_getname,
 616         .poll              = datagram_poll,
 617         .ioctl             = inet_ioctl,
 618         .listen            = sock_no_listen,
 619         .shutdown          = inet_shutdown,
 620         .setsockopt        = sock_common_setsockopt,
 621         .getsockopt        = sock_common_getsockopt,
 622         .sendmsg           = inet_sendmsg,
 623         .recvmsg           = sock_common_recvmsg,
 624         .mmap              = sock_no_mmap,
 625         .sendpage          = sock_no_sendpage,
 626 #ifdef CONFIG_COMPAT
 627         .compat_setsockopt = compat_sock_common_setsockopt,
 628         .compat_getsockopt = compat_sock_common_getsockopt,
 629 #endif
 630 };
 631
 632 static struct inet_protosw l2tp_ip_protosw = {
 633         .type           = SOCK_DGRAM,
 634         .protocol       = IPPROTO_L2TP,
 635         .prot           = &l2tp_ip_prot,
 636         .ops            = &l2tp_ip_ops,
 637 };
 638
 639 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 640         .handler        = l2tp_ip_recv,
 641         .netns_ok       = 1,
 642 };
 643
 644 static int __init l2tp_ip_init(void)
 645 {
 646         int err;
 647
 648         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 649
 650         err = proto_register(&l2tp_ip_prot, 1);
 651         if (err != 0)
 652                 goto out;
 653
 654         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 655         if (err)
 656                 goto out1;
 657
 658         inet_register_protosw(&l2tp_ip_protosw);
 659         return 0;
 660
 661 out1:
 662         proto_unregister(&l2tp_ip_prot);
 663 out:
 664         return err;
 665 }
 666
 667 static void __exit l2tp_ip_exit(void)
 668 {
 669         inet_unregister_protosw(&l2tp_ip_protosw);
 670         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 671         proto_unregister(&l2tp_ip_prot);
 672 }
 673
 674 module_init(l2tp_ip_init);
 675 module_exit(l2tp_ip_exit);
 676
 677 MODULE_LICENSE("GPL");
 678 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 679 MODULE_DESCRIPTION("L2TP over IP");
 680 MODULE_VERSION("1.0");
 681
 682 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 683  * enums
 684  */
 685 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 686 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);