net/l2tp/l2tp_ip.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* L2TPv3 IP encapsulation support
   3  *
   4  * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
   5  */
   6
   7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   8
   9 #include <asm/ioctls.h>
  10 #include <linux/icmp.h>
  11 #include <linux/module.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/random.h>
  14 #include <linux/socket.h>
  15 #include <linux/l2tp.h>
  16 #include <linux/in.h>
  17 #include <net/sock.h>
  18 #include <net/ip.h>
  19 #include <net/icmp.h>
  20 #include <net/udp.h>
  21 #include <net/inet_common.h>
  22 #include <net/tcp_states.h>
  23 #include <net/protocol.h>
  24 #include <net/xfrm.h>
  25
  26 #include "l2tp_core.h"
  27
  28 struct l2tp_ip_sock {
  29         /* inet_sock has to be the first member of l2tp_ip_sock */
  30         struct inet_sock        inet;
  31
  32         u32                     conn_id;
  33         u32                     peer_conn_id;
  34 };
  35
  36 static DEFINE_RWLOCK(l2tp_ip_lock);
  37 static struct hlist_head l2tp_ip_table;
  38 static struct hlist_head l2tp_ip_bind_table;
  39
  40 static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
  41 {
  42         return (struct l2tp_ip_sock *)sk;
  43 }
  44
  45 static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
  46                                           __be32 raddr, int dif, u32 tunnel_id)
  47 {
  48         struct sock *sk;
  49
  50         sk_for_each_bound(sk, &l2tp_ip_bind_table) {
  51                 const struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
  52                 const struct inet_sock *inet = inet_sk(sk);
  53
  54                 if (!net_eq(sock_net(sk), net))
  55                         continue;
  56
  57                 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
  58                         continue;
  59
  60                 if (inet->inet_rcv_saddr && laddr &&
  61                     inet->inet_rcv_saddr != laddr)
  62                         continue;
  63
  64                 if (inet->inet_daddr && raddr && inet->inet_daddr != raddr)
  65                         continue;
  66
  67                 if (l2tp->conn_id != tunnel_id)
  68                         continue;
  69
  70                 goto found;
  71         }
  72
  73         sk = NULL;
  74 found:
  75         return sk;
  76 }
  77
  78 /* When processing receive frames, there are two cases to
  79  * consider. Data frames consist of a non-zero session-id and an
  80  * optional cookie. Control frames consist of a regular L2TP header
  81  * preceded by 32-bits of zeros.
  82  *
  83  * L2TPv3 Session Header Over IP
  84  *
  85  *  0                   1                   2                   3
  86  *  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
  87  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  88  * |                           Session ID                          |
  89  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  90  * |               Cookie (optional, maximum 64 bits)...
  91  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  92  *                                                                 |
  93  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  94  *
  95  * L2TPv3 Control Message Header Over IP
  96  *
  97  *  0                   1                   2                   3
  98  *  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
  99  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 100  * |                      (32 bits of zeros)                       |
 101  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 102  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 103  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 104  * |                     Control Connection ID                     |
 105  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 106  * |               Ns              |               Nr              |
 107  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 108  *
 109  * All control frames are passed to userspace.
 110  */
 111 static int l2tp_ip_recv(struct sk_buff *skb)
 112 {
 113         struct net *net = dev_net(skb->dev);
 114         struct sock *sk;
 115         u32 session_id;
 116         u32 tunnel_id;
 117         unsigned char *ptr, *optr;
 118         struct l2tp_session *session;
 119         struct l2tp_tunnel *tunnel = NULL;
 120         struct iphdr *iph;
 121
 122         if (!pskb_may_pull(skb, 4))
 123                 goto discard;
 124
 125         /* Point to L2TP header */
 126         optr = skb->data;
 127         ptr = skb->data;
 128         session_id = ntohl(*((__be32 *)ptr));
 129         ptr += 4;
 130
 131         /* RFC3931: L2TP/IP packets have the first 4 bytes containing
 132          * the session_id. If it is 0, the packet is a L2TP control
 133          * frame and the session_id value can be discarded.
 134          */
 135         if (session_id == 0) {
 136                 __skb_pull(skb, 4);
 137                 goto pass_up;
 138         }
 139
 140         /* Ok, this is a data packet. Lookup the session. */
 141         session = l2tp_session_get(net, session_id);
 142         if (!session)
 143                 goto discard;
 144
 145         tunnel = session->tunnel;
 146         if (!tunnel)
 147                 goto discard_sess;
 148
 149         if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
 150                 goto discard_sess;
 151
 152         l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
 153         l2tp_session_dec_refcount(session);
 154
 155         return 0;
 156
 157 pass_up:
 158         /* Get the tunnel_id from the L2TP header */
 159         if (!pskb_may_pull(skb, 12))
 160                 goto discard;
 161
 162         if ((skb->data[0] & 0xc0) != 0xc0)
 163                 goto discard;
 164
 165         tunnel_id = ntohl(*(__be32 *)&skb->data[4]);
 166         iph = (struct iphdr *)skb_network_header(skb);
 167
 168         read_lock_bh(&l2tp_ip_lock);
 169         sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb),
 170                                    tunnel_id);
 171         if (!sk) {
 172                 read_unlock_bh(&l2tp_ip_lock);
 173                 goto discard;
 174         }
 175         sock_hold(sk);
 176         read_unlock_bh(&l2tp_ip_lock);
 177
 178         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 179                 goto discard_put;
 180
 181         nf_reset_ct(skb);
 182
 183         return sk_receive_skb(sk, skb, 1);
 184
 185 discard_sess:
 186         l2tp_session_dec_refcount(session);
 187         goto discard;
 188
 189 discard_put:
 190         sock_put(sk);
 191
 192 discard:
 193         kfree_skb(skb);
 194         return 0;
 195 }
 196
 197 static int l2tp_ip_hash(struct sock *sk)
 198 {
 199         if (sk_unhashed(sk)) {
 200                 write_lock_bh(&l2tp_ip_lock);
 201                 sk_add_node(sk, &l2tp_ip_table);
 202                 write_unlock_bh(&l2tp_ip_lock);
 203         }
 204         return 0;
 205 }
 206
 207 static void l2tp_ip_unhash(struct sock *sk)
 208 {
 209         if (sk_unhashed(sk))
 210                 return;
 211         write_lock_bh(&l2tp_ip_lock);
 212         sk_del_node_init(sk);
 213         write_unlock_bh(&l2tp_ip_lock);
 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         l2tp_ip_hash(sk);
 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 l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk);
 237         struct sk_buff *skb;
 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 = addr->l2tp_addr.s_addr;
 276                 inet->inet_saddr = addr->l2tp_addr.s_addr;
 277         }
 278         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 279                 inet->inet_saddr = 0;  /* Use device */
 280
 281         write_lock_bh(&l2tp_ip_lock);
 282         if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
 283                                   sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
 284                 write_unlock_bh(&l2tp_ip_lock);
 285                 ret = -EADDRINUSE;
 286                 goto out;
 287         }
 288
 289         sk_dst_reset(sk);
 290         l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
 291
 292         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 293         sk_del_node_init(sk);
 294         write_unlock_bh(&l2tp_ip_lock);
 295
 296         ret = 0;
 297         sock_reset_flag(sk, SOCK_ZAPPED);
 298
 299 out:
 300         release_sock(sk);
 301
 302         return ret;
 303 }
 304
 305 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 306 {
 307         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 308         int rc;
 309
 310         if (addr_len < sizeof(*lsa))
 311                 return -EINVAL;
 312
 313         if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
 314                 return -EINVAL;
 315
 316         lock_sock(sk);
 317
 318         /* Must bind first - autobinding does not work */
 319         if (sock_flag(sk, SOCK_ZAPPED)) {
 320                 rc = -EINVAL;
 321                 goto out_sk;
 322         }
 323
 324         rc = __ip4_datagram_connect(sk, uaddr, addr_len);
 325         if (rc < 0)
 326                 goto out_sk;
 327
 328         l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 329
 330         write_lock_bh(&l2tp_ip_lock);
 331         hlist_del_init(&sk->sk_bind_node);
 332         sk_add_bind_node(sk, &l2tp_ip_bind_table);
 333         write_unlock_bh(&l2tp_ip_lock);
 334
 335 out_sk:
 336         release_sock(sk);
 337
 338         return rc;
 339 }
 340
 341 static int l2tp_ip_disconnect(struct sock *sk, int flags)
 342 {
 343         if (sock_flag(sk, SOCK_ZAPPED))
 344                 return 0;
 345
 346         return __udp_disconnect(sk, flags);
 347 }
 348
 349 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
 350                            int peer)
 351 {
 352         struct sock *sk         = sock->sk;
 353         struct inet_sock *inet  = inet_sk(sk);
 354         struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
 355         struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
 356
 357         memset(lsa, 0, sizeof(*lsa));
 358         lsa->l2tp_family = AF_INET;
 359         if (peer) {
 360                 if (!inet->inet_dport)
 361                         return -ENOTCONN;
 362                 lsa->l2tp_conn_id = lsk->peer_conn_id;
 363                 lsa->l2tp_addr.s_addr = inet->inet_daddr;
 364         } else {
 365                 __be32 addr = inet->inet_rcv_saddr;
 366
 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
 415                 rc = -EINVAL;
 416                 if (msg->msg_namelen < sizeof(*lip))
 417                         goto out;
 418
 419                 if (lip->l2tp_family != AF_INET) {
 420                         rc = -EAFNOSUPPORT;
 421                         if (lip->l2tp_family != AF_UNSPEC)
 422                                 goto out;
 423                 }
 424
 425                 daddr = lip->l2tp_addr.s_addr;
 426         } else {
 427                 rc = -EDESTADDRREQ;
 428                 if (sk->sk_state != TCP_ESTABLISHED)
 429                         goto out;
 430
 431                 daddr = inet->inet_daddr;
 432                 connected = 1;
 433         }
 434
 435         /* Allocate a socket buffer */
 436         rc = -ENOMEM;
 437         skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
 438                            4 + len, 0, GFP_KERNEL);
 439         if (!skb)
 440                 goto error;
 441
 442         /* Reserve space for headers, putting IP header on 4-byte boundary. */
 443         skb_reserve(skb, 2 + NET_SKB_PAD);
 444         skb_reset_network_header(skb);
 445         skb_reserve(skb, sizeof(struct iphdr));
 446         skb_reset_transport_header(skb);
 447
 448         /* Insert 0 session_id */
 449         *((__be32 *)skb_put(skb, 4)) = 0;
 450
 451         /* Copy user data into skb */
 452         rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 453         if (rc < 0) {
 454                 kfree_skb(skb);
 455                 goto error;
 456         }
 457
 458         fl4 = &inet->cork.fl.u.ip4;
 459         if (connected)
 460                 rt = (struct rtable *)__sk_dst_check(sk, 0);
 461
 462         rcu_read_lock();
 463         if (!rt) {
 464                 const struct ip_options_rcu *inet_opt;
 465
 466                 inet_opt = rcu_dereference(inet->inet_opt);
 467
 468                 /* Use correct destination address if we have options. */
 469                 if (inet_opt && inet_opt->opt.srr)
 470                         daddr = inet_opt->opt.faddr;
 471
 472                 /* If this fails, retransmit mechanism of transport layer will
 473                  * keep trying until route appears or the connection times
 474                  * itself out.
 475                  */
 476                 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
 477                                            daddr, inet->inet_saddr,
 478                                            inet->inet_dport, inet->inet_sport,
 479                                            sk->sk_protocol, RT_CONN_FLAGS(sk),
 480                                            sk->sk_bound_dev_if);
 481                 if (IS_ERR(rt))
 482                         goto no_route;
 483                 if (connected) {
 484                         sk_setup_caps(sk, &rt->dst);
 485                 } else {
 486                         skb_dst_set(skb, &rt->dst);
 487                         goto xmit;
 488                 }
 489         }
 490
 491         /* We dont need to clone dst here, it is guaranteed to not disappear.
 492          *  __dev_xmit_skb() might force a refcount if needed.
 493          */
 494         skb_dst_set_noref(skb, &rt->dst);
 495
 496 xmit:
 497         /* Queue the packet to IP for output */
 498         rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
 499         rcu_read_unlock();
 500
 501 error:
 502         if (rc >= 0)
 503                 rc = len;
 504
 505 out:
 506         release_sock(sk);
 507         return rc;
 508
 509 no_route:
 510         rcu_read_unlock();
 511         IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
 512         kfree_skb(skb);
 513         rc = -EHOSTUNREACH;
 514         goto out;
 515 }
 516
 517 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 518                            size_t len, int noblock, int flags, int *addr_len)
 519 {
 520         struct inet_sock *inet = inet_sk(sk);
 521         size_t copied = 0;
 522         int err = -EOPNOTSUPP;
 523         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 524         struct sk_buff *skb;
 525
 526         if (flags & MSG_OOB)
 527                 goto out;
 528
 529         skb = skb_recv_datagram(sk, flags, noblock, &err);
 530         if (!skb)
 531                 goto out;
 532
 533         copied = skb->len;
 534         if (len < copied) {
 535                 msg->msg_flags |= MSG_TRUNC;
 536                 copied = len;
 537         }
 538
 539         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 540         if (err)
 541                 goto done;
 542
 543         sock_recv_timestamp(msg, sk, skb);
 544
 545         /* Copy the address. */
 546         if (sin) {
 547                 sin->sin_family = AF_INET;
 548                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 549                 sin->sin_port = 0;
 550                 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 551                 *addr_len = sizeof(*sin);
 552         }
 553         if (inet->cmsg_flags)
 554                 ip_cmsg_recv(msg, skb);
 555         if (flags & MSG_TRUNC)
 556                 copied = skb->len;
 557 done:
 558         skb_free_datagram(sk, skb);
 559 out:
 560         return err ? err : copied;
 561 }
 562
 563 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 564 {
 565         struct sk_buff *skb;
 566         int amount;
 567
 568         switch (cmd) {
 569         case SIOCOUTQ:
 570                 amount = sk_wmem_alloc_get(sk);
 571                 break;
 572         case SIOCINQ:
 573                 spin_lock_bh(&sk->sk_receive_queue.lock);
 574                 skb = skb_peek(&sk->sk_receive_queue);
 575                 amount = skb ? skb->len : 0;
 576                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 577                 break;
 578
 579         default:
 580                 return -ENOIOCTLCMD;
 581         }
 582
 583         return put_user(amount, (int __user *)arg);
 584 }
 585 EXPORT_SYMBOL_GPL(l2tp_ioctl);
 586
 587 static struct proto l2tp_ip_prot = {
 588         .name              = "L2TP/IP",
 589         .owner             = THIS_MODULE,
 590         .init              = l2tp_ip_open,
 591         .close             = l2tp_ip_close,
 592         .bind              = l2tp_ip_bind,
 593         .connect           = l2tp_ip_connect,
 594         .disconnect        = l2tp_ip_disconnect,
 595         .ioctl             = l2tp_ioctl,
 596         .destroy           = l2tp_ip_destroy_sock,
 597         .setsockopt        = ip_setsockopt,
 598         .getsockopt        = ip_getsockopt,
 599         .sendmsg           = l2tp_ip_sendmsg,
 600         .recvmsg           = l2tp_ip_recvmsg,
 601         .backlog_rcv       = l2tp_ip_backlog_recv,
 602         .hash              = l2tp_ip_hash,
 603         .unhash            = l2tp_ip_unhash,
 604         .obj_size          = sizeof(struct l2tp_ip_sock),
 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         .gettstamp         = sock_gettstamp,
 619         .listen            = sock_no_listen,
 620         .shutdown          = inet_shutdown,
 621         .setsockopt        = sock_common_setsockopt,
 622         .getsockopt        = sock_common_getsockopt,
 623         .sendmsg           = inet_sendmsg,
 624         .recvmsg           = sock_common_recvmsg,
 625         .mmap              = sock_no_mmap,
 626         .sendpage          = sock_no_sendpage,
 627 };
 628
 629 static struct inet_protosw l2tp_ip_protosw = {
 630         .type           = SOCK_DGRAM,
 631         .protocol       = IPPROTO_L2TP,
 632         .prot           = &l2tp_ip_prot,
 633         .ops            = &l2tp_ip_ops,
 634 };
 635
 636 static struct net_protocol l2tp_ip_protocol __read_mostly = {
 637         .handler        = l2tp_ip_recv,
 638         .netns_ok       = 1,
 639 };
 640
 641 static int __init l2tp_ip_init(void)
 642 {
 643         int err;
 644
 645         pr_info("L2TP IP encapsulation support (L2TPv3)\n");
 646
 647         err = proto_register(&l2tp_ip_prot, 1);
 648         if (err != 0)
 649                 goto out;
 650
 651         err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 652         if (err)
 653                 goto out1;
 654
 655         inet_register_protosw(&l2tp_ip_protosw);
 656         return 0;
 657
 658 out1:
 659         proto_unregister(&l2tp_ip_prot);
 660 out:
 661         return err;
 662 }
 663
 664 static void __exit l2tp_ip_exit(void)
 665 {
 666         inet_unregister_protosw(&l2tp_ip_protosw);
 667         inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
 668         proto_unregister(&l2tp_ip_prot);
 669 }
 670
 671 module_init(l2tp_ip_init);
 672 module_exit(l2tp_ip_exit);
 673
 674 MODULE_LICENSE("GPL");
 675 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 676 MODULE_DESCRIPTION("L2TP over IP");
 677 MODULE_VERSION("1.0");
 678
 679 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 680  * enums
 681  */
 682 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
 683 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);