net/l2tp/l2tp_ip.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * L2TPv3 IP encapsulation support
   4  *
   5  * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <asm/ioctls.h>
  11 #include <linux/icmp.h>
  12 #include <linux/module.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/random.h>
  15 #include <linux/socket.h>
  16 #include <linux/l2tp.h>
  17 #include <linux/in.h>
  18 #include <net/sock.h>
  19 #include <net/ip.h>
  20 #include <net/icmp.h>
  21 #include <net/udp.h>
  22 #include <net/inet_common.h>
  23 #include <net/inet_hashtables.h>
  24 #include <net/tcp_states.h>
  25 #include <net/protocol.h>
  26 #include <net/xfrm.h>
  27
  28 #include "l2tp_core.h"
  29
  30 struct l2tp_ip_sock {
  31         /* inet_sock has to be the first member of l2tp_ip_sock */
  32         struct inet_sock        inet;
  33
  34         u32                     conn_id;
  35         u32                     peer_conn_id;
  36 };
  37
  38 static DEFINE_RWLOCK(l2tp_ip_lock);
  39 static struct hlist_head l2tp_ip_table;
  40 static struct hlist_head l2tp_ip_bind_table;
  41
  42 static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
  43 {
  44         return (struct l2tp_ip_sock *)sk;
  45 }
  46
  47 static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
  48                                           __be32 raddr, int dif, u32 tunnel_id)
  49 {
  50         struct sock *sk;
  51
  52         sk_for_each_bound(sk, &l2tp_ip_bind_table) {
  53                 const struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
  54                 const struct inet_sock *inet = inet_sk(sk);
  55
  56                 if (!net_eq(sock_net(sk), net))
  57                         continue;
  58
  59                 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
  60                         continue;
  61
  62                 if (inet->inet_rcv_saddr && laddr &&
  63                     inet->inet_rcv_saddr != laddr)
  64                         continue;
  65
  66                 if (inet->inet_daddr && raddr && inet->inet_daddr != raddr)
  67                         continue;
  68
  69                 if (l2tp->conn_id != tunnel_id)
  70                         continue;
  71
  72                 goto found;
  73         }
  74
  75         sk = NULL;
  76 found:
  77         return sk;
  78 }
  79
  80 /* When processing receive frames, there are two cases to
  81  * consider. Data frames consist of a non-zero session-id and an
  82  * optional cookie. Control frames consist of a regular L2TP header
  83  * preceded by 32-bits of zeros.
  84  *
  85  * L2TPv3 Session Header Over IP
  86  *
  87  *  0                   1                   2                   3
  88  *  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
  89  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  90  * |                           Session ID                          |
  91  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  92  * |               Cookie (optional, maximum 64 bits)...
  93  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  94  *                                                                 |
  95  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  96  *
  97  * L2TPv3 Control Message Header Over IP
  98  *
  99  *  0                   1                   2                   3
 100  *  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
 101  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 102  * |                      (32 bits of zeros)                       |
 103  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 104  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 105  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 106  * |                     Control Connection ID                     |
 107  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 108  * |               Ns              |               Nr              |
 109  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 110  *
 111  * All control frames are passed to userspace.
 112  */
 113 static int l2tp_ip_recv(struct sk_buff *skb)
 114 {
 115         struct net *net = dev_net(skb->dev);
 116         struct sock *sk;
 117         u32 session_id;
 118         u32 tunnel_id;
 119         unsigned char *ptr, *optr;
 120         struct l2tp_session *session;
 121         struct l2tp_tunnel *tunnel = NULL;
 122         struct iphdr *iph;
 123         int length;
 124
 125         if (!pskb_may_pull(skb, 4))
 126                 goto discard;
 127
 128         /* Point to L2TP header */
 129         optr = ptr = skb->data;
 130         session_id = ntohl(*((__be32 *) ptr));
 131         ptr += 4;
 132
 133         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 134          * the session_id. If it is 0, the packet is a L2TP control
 135          * frame and the session_id value can be discarded.
 136          */
 137         if (session_id == 0) {
 138                 __skb_pull(skb, 4);
 139                 goto pass_up;
 140         }
 141
 142         /* Ok, this is a data packet. Lookup the session. */
 143         session = l2tp_session_get(net, session_id);
 144         if (!session)
 145                 goto discard;
 146
 147         tunnel = session->tunnel;
 148         if (!tunnel)
 149                 goto discard_sess;
 150
 151         /* Trace packet contents, if enabled */
 152         if (tunnel->debug & L2TP_MSG_DATA) {
 153                 length = min(32u, skb->len);
 154                 if (!pskb_may_pull(skb, length))
 155                         goto discard_sess;
 156
 157                 /* Point to L2TP header */
 158                 optr = ptr = skb->data;
 159                 ptr += 4;
 160                 pr_debug("%s: ip recv\n", tunnel->name);
 161                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
 162         }
 163
 164         if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
 165                 goto discard_sess;
 166
 167         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
 168         l2tp_session_dec_refcount(session);
 169
 170         return 0;
 171
 172 pass_up:
 173         /* Get the tunnel_id from the L2TP header */
 174         if (!pskb_may_pull(skb, 12))
 175                 goto discard;
 176
 177         if ((skb->data[0] & 0xc0) != 0xc0)
 178                 goto discard;
 179
 180         tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
 181         iph = (struct iphdr *)skb_network_header(skb);
 182
 183         read_lock_bh(&l2tp_ip_lock);
 184         sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb),
 185                                    tunnel_id);
 186         if (!sk) {
 187                 read_unlock_bh(&l2tp_ip_lock);
 188                 goto discard;
 189         }
 190         sock_hold(sk);
 191         read_unlock_bh(&l2tp_ip_lock);
 192
 193         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 194                 goto discard_put;
 195
 196         nf_reset_ct(skb);
 197
 198         return sk_receive_skb(sk, skb, 1);
 199
 200 discard_sess:
 201         l2tp_session_dec_refcount(session);
 202         goto discard;
 203
 204 discard_put:
 205         sock_put(sk);
 206
 207 discard:
 208         kfree_skb(skb);
 209         return 0;
 210 }
 211
 212 static int l2tp_ip_open(struct sock *sk)
 213 {
 214         /* Prevent autobind. We don't have ports. */
 215         inet_sk(sk)->inet_num = IPPROTO_L2TP;
 216
 217         write_lock_bh(&l2tp_ip_lock);
 218         sk_add_node(sk, &l2tp_ip_table);
 219         write_unlock_bh(&l2tp_ip_lock);
 220
 221         return 0;
 222 }
 223
 224 static void l2tp_ip_close(struct sock *sk, long timeout)
 225 {
 226         write_lock_bh(&l2tp_ip_lock);
 227         hlist_del_init(&sk->sk_bind_node);
 228         sk_del_node_init(sk);
 229         write_unlock_bh(&l2tp_ip_lock);
 230         sk_common_release(sk);
 231 }
 232
 233 static void l2tp_ip_destroy_sock(struct sock *sk)
 234 {
 235         struct sk_buff *skb;
 236         struct l2tp_tunnel *tunnel = sk->sk_user_data;
 237
 238         while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
 239                 kfree_skb(skb);
 240
 241         if (tunnel)
 242                 l2tp_tunnel_delete(tunnel);
 243 }
 244
 245 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 246 {
 247         struct inet_sock *inet = inet_sk(sk);
 248         struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
 249         struct net *net = sock_net(sk);
 250         int ret;
 251         int chk_addr_ret;
 252
 253         if (addr_len < sizeof(struct sockaddr_l2tpip))
 254                 return -EINVAL;
 255         if (addr->l2tp_family != AF_INET)
 256                 return -EINVAL;
 257
 258         lock_sock(sk);
 259
 260         ret = -EINVAL;
 261         if (!sock_flag(sk, SOCK_ZAPPED))
 262                 goto out;
 263
 264         if (sk->sk_state != TCP_CLOSE)
 265                 goto out;
 266
 267         chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
 268         ret = -EADDRNOTAVAIL;
 269         if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
 270             chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 271                 goto out;
 272
 273         if (addr->l2tp_addr.s_addr)
 274                 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
 275         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 276                 inet->inet_saddr = 0;  /* Use device */
 277
 278         write_lock_bh(&l2tp_ip_lock);
 279         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
 280                                   sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
 281                 write_unlock_bh(&l2tp_ip_lock);
 282                 ret = -EADDRINUSE;
 283                 goto out;
 284         }
 285
 286         sk_dst_reset(sk);
 287         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 288
 289         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 290         sk_del_node_init(sk);
 291         write_unlock_bh(&l2tp_ip_lock);
 292
 293         ret = 0;
 294         sock_reset_flag(sk, SOCK_ZAPPED);
 295
 296 out:
 297         release_sock(sk);
 298
 299         return ret;
 300 }
 301
 302 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 303 {
 304         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 305         int rc;
 306
 307         if (addr_len < sizeof(*lsa))
 308                 return -EINVAL;
 309
 310         if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 311                 return -EINVAL;
 312
 313         lock_sock(sk);
 314
 315         /* Must bind first - autobinding does not work */
 316         if (sock_flag(sk, SOCK_ZAPPED)) {
 317                 rc = -EINVAL;
 318                 goto out_sk;
 319         }
 320
 321         rc = __ip4_datagram_connect(sk, uaddr, addr_len);
 322         if (rc < 0)
 323                 goto out_sk;
 324
 325         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 326
 327         write_lock_bh(&l2tp_ip_lock);
 328         hlist_del_init(&sk->sk_bind_node);
 329         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 330         write_unlock_bh(&l2tp_ip_lock);
 331
 332 out_sk:
 333         release_sock(sk);
 334
 335         return rc;
 336 }
 337
 338 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 339 {
 340         if (sock_flag(sk, SOCK_ZAPPED))
 341                 return 0;
 342
 343         return __udp_disconnect(sk, flags);
 344 }
 345
 346 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 347                            int peer)
 348 {
 349         struct sock *sk         = sock->sk;
 350         struct inet_sock *inet  = inet_sk(sk);
 351         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 352         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 353
 354         memset(lsa, 0, sizeof(*lsa));
 355         lsa->l2tp_family = AF_INET;
 356         if (peer) {
 357                 if (!inet->inet_dport)
 358                         return -ENOTCONN;
 359                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 360                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 361         } else {
 362                 __be32 addr = inet->inet_rcv_saddr;
 363                 if (!addr)
 364                         addr = inet->inet_saddr;
 365                 lsa->l2tp_conn_id = lsk->conn_id;
 366                 lsa->l2tp_addr.s_addr = addr;
 367         }
 368         return sizeof(*lsa);
 369 }
 370
 371 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
 372 {
 373         int rc;
 374
 375         /* Charge it to the socket, dropping if the queue is full. */
 376         rc = sock_queue_rcv_skb(sk, skb);
 377         if (rc < 0)
 378                 goto drop;
 379
 380         return 0;
 381
 382 drop:
 383         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
 384         kfree_skb(skb);
 385         return 0;
 386 }
 387
 388 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
 389  * control frames.
 390  */
 391 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 392 {
 393         struct sk_buff *skb;
 394         int rc;
 395         struct inet_sock *inet = inet_sk(sk);
 396         struct rtable *rt = NULL;
 397         struct flowi4 *fl4;
 398         int connected = 0;
 399         __be32 daddr;
 400
 401         lock_sock(sk);
 402
 403         rc = -ENOTCONN;
 404         if (sock_flag(sk, SOCK_DEAD))
 405                 goto out;
 406
 407         /* Get and verify the address. */
 408         if (msg->msg_name) {
 409                 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
 410                 rc = -EINVAL;
 411                 if (msg->msg_namelen < sizeof(*lip))
 412                         goto out;
 413
 414                 if (lip->l2tp_family != AF_INET) {
 415                         rc = -EAFNOSUPPORT;
 416                         if (lip->l2tp_family != AF_UNSPEC)
 417                                 goto out;
 418                 }
 419
 420                 daddr = lip->l2tp_addr.s_addr;
 421         } else {
 422                 rc = -EDESTADDRREQ;
 423                 if (sk->sk_state != TCP_ESTABLISHED)
 424                         goto out;
 425
 426                 daddr = inet->inet_daddr;
 427                 connected = 1;
 428         }
 429
 430         /* Allocate a socket buffer */
 431         rc = -ENOMEM;
 432         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 433                            4 + len, 0, GFP_KERNEL);
 434         if (!skb)
 435                 goto error;
 436
 437         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 438         skb_reserve(skb, 2 + NET_SKB_PAD);
 439         skb_reset_network_header(skb);
 440         skb_reserve(skb, sizeof(struct iphdr));
 441         skb_reset_transport_header(skb);
 442
 443         /* Insert 0 session_id */
 444         *((__be32 *) skb_put(skb, 4)) = 0;
 445
 446         /* Copy user data into skb */
 447         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 448         if (rc < 0) {
 449                 kfree_skb(skb);
 450                 goto error;
 451         }
 452
 453         fl4 = &inet->cork.fl.u.ip4;
 454         if (connected)
 455                 rt = (struct rtable *) __sk_dst_check(sk, 0);
 456
 457         rcu_read_lock();
 458         if (rt == NULL) {
 459                 const struct ip_options_rcu *inet_opt;
 460
 461                 inet_opt = rcu_dereference(inet->inet_opt);
 462
 463                 /* Use correct destination address if we have options. */
 464                 if (inet_opt && inet_opt->opt.srr)
 465                         daddr = inet_opt->opt.faddr;
 466
 467                 /* If this fails, retransmit mechanism of transport layer will
 468                  * keep trying until route appears or the connection times
 469                  * itself out.
 470                  */
 471                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 472                                            daddr, inet->inet_saddr,
 473                                            inet->inet_dport, inet->inet_sport,
 474                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 475                                            sk->sk_bound_dev_if);
 476                 if (IS_ERR(rt))
 477                         goto no_route;
 478                 if (connected) {
 479                         sk_setup_caps(sk, &rt->dst);
 480                 } else {
 481                         skb_dst_set(skb, &rt->dst);
 482                         goto xmit;
 483                 }
 484         }
 485
 486         /* We dont need to clone dst here, it is guaranteed to not disappear.
 487          *  __dev_xmit_skb() might force a refcount if needed.
 488          */
 489         skb_dst_set_noref(skb, &rt->dst);
 490
 491 xmit:
 492         /* Queue the packet to IP for output */
 493         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 494         rcu_read_unlock();
 495
 496 error:
 497         if (rc >= 0)
 498                 rc = len;
 499
 500 out:
 501         release_sock(sk);
 502         return rc;
 503
 504 no_route:
 505         rcu_read_unlock();
 506         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 507         kfree_skb(skb);
 508         rc = -EHOSTUNREACH;
 509         goto out;
 510 }
 511
 512 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 513                            size_t len, int noblock, int flags, int *addr_len)
 514 {
 515         struct inet_sock *inet = inet_sk(sk);
 516         size_t copied = 0;
 517         int err = -EOPNOTSUPP;
 518         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 519         struct sk_buff *skb;
 520
 521         if (flags & MSG_OOB)
 522                 goto out;
 523
 524         skb = skb_recv_datagram(sk, flags, noblock, &err);
 525         if (!skb)
 526                 goto out;
 527
 528         copied = skb->len;
 529         if (len < copied) {
 530                 msg->msg_flags |= MSG_TRUNC;
 531                 copied = len;
 532         }
 533
 534         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 535         if (err)
 536                 goto done;
 537
 538         sock_recv_timestamp(msg, sk, skb);
 539
 540         /* Copy the address. */
 541         if (sin) {
 542                 sin->sin_family = AF_INET;
 543                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 544                 sin->sin_port = 0;
 545                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 546                 *addr_len = sizeof(*sin);
 547         }
 548         if (inet->cmsg_flags)
 549                 ip_cmsg_recv(msg, skb);
 550         if (flags & MSG_TRUNC)
 551                 copied = skb->len;
 552 done:
 553         skb_free_datagram(sk, skb);
 554 out:
 555         return err ? err : copied;
 556 }
 557
 558 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 559 {
 560         struct sk_buff *skb;
 561         int amount;
 562
 563         switch (cmd) {
 564         case SIOCOUTQ:
 565                 amount = sk_wmem_alloc_get(sk);
 566                 break;
 567         case SIOCINQ:
 568                 spin_lock_bh(&sk->sk_receive_queue.lock);
 569                 skb = skb_peek(&sk->sk_receive_queue);
 570                 amount = skb ? skb->len : 0;
 571                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 572                 break;
 573
 574         default:
 575                 return -ENOIOCTLCMD;
 576         }
 577
 578         return put_user(amount, (int __user *)arg);
 579 }
 580 EXPORT_SYMBOL(l2tp_ioctl);
 581
 582 static struct proto l2tp_ip_prot = {
 583         .name              = "L2TP/IP",
 584         .owner             = THIS_MODULE,
 585         .init              = l2tp_ip_open,
 586         .close             = l2tp_ip_close,
 587         .bind              = l2tp_ip_bind,
 588         .connect           = l2tp_ip_connect,
 589         .disconnect        = l2tp_ip_disconnect,
 590         .ioctl             = l2tp_ioctl,
 591         .destroy           = l2tp_ip_destroy_sock,
 592         .setsockopt        = ip_setsockopt,
 593         .getsockopt        = ip_getsockopt,
 594         .sendmsg           = l2tp_ip_sendmsg,
 595         .recvmsg           = l2tp_ip_recvmsg,
 596         .backlog_rcv       = l2tp_ip_backlog_recv,
 597         .hash              = inet_hash,
 598         .unhash            = inet_unhash,
 599         .obj_size          = sizeof(struct l2tp_ip_sock),
 600 #ifdef CONFIG_COMPAT
 601         .compat_setsockopt = compat_ip_setsockopt,
 602         .compat_getsockopt = compat_ip_getsockopt,
 603 #endif
 604 };
 605
 606 static const struct proto_ops l2tp_ip_ops = {
 607         .family            = PF_INET,
 608         .owner             = THIS_MODULE,
 609         .release           = inet_release,
 610         .bind              = inet_bind,
 611         .connect           = inet_dgram_connect,
 612         .socketpair        = sock_no_socketpair,
 613         .accept            = sock_no_accept,
 614         .getname           = l2tp_ip_getname,
 615         .poll              = datagram_poll,
 616         .ioctl             = inet_ioctl,
 617         .gettstamp         = sock_gettstamp,
 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);