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, NULL, session_id, true); 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, tunnel->recv_payload_hook); 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 if (session->deref) 203 session->deref(session); 204 l2tp_session_dec_refcount(session); 205 goto discard; 206 207 discard_put: 208 sock_put(sk); 209 210 discard: 211 kfree_skb(skb); 212 return 0; 213 } 214 215 static int l2tp_ip_open(struct sock *sk) 216 { 217 /* Prevent autobind. We don't have ports. */ 218 inet_sk(sk)->inet_num = IPPROTO_L2TP; 219 220 write_lock_bh(&l2tp_ip_lock); 221 sk_add_node(sk, &l2tp_ip_table); 222 write_unlock_bh(&l2tp_ip_lock); 223 224 return 0; 225 } 226 227 static void l2tp_ip_close(struct sock *sk, long timeout) 228 { 229 write_lock_bh(&l2tp_ip_lock); 230 hlist_del_init(&sk->sk_bind_node); 231 sk_del_node_init(sk); 232 write_unlock_bh(&l2tp_ip_lock); 233 sk_common_release(sk); 234 } 235 236 static void l2tp_ip_destroy_sock(struct sock *sk) 237 { 238 struct sk_buff *skb; 239 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); 240 241 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 242 kfree_skb(skb); 243 244 if (tunnel) { 245 l2tp_tunnel_closeall(tunnel); 246 sock_put(sk); 247 } 248 249 sk_refcnt_debug_dec(sk); 250 } 251 252 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 253 { 254 struct inet_sock *inet = inet_sk(sk); 255 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr; 256 struct net *net = sock_net(sk); 257 int ret; 258 int chk_addr_ret; 259 260 if (addr_len < sizeof(struct sockaddr_l2tpip)) 261 return -EINVAL; 262 if (addr->l2tp_family != AF_INET) 263 return -EINVAL; 264 265 lock_sock(sk); 266 267 ret = -EINVAL; 268 if (!sock_flag(sk, SOCK_ZAPPED)) 269 goto out; 270 271 if (sk->sk_state != TCP_CLOSE) 272 goto out; 273 274 chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr); 275 ret = -EADDRNOTAVAIL; 276 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL && 277 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST) 278 goto out; 279 280 if (addr->l2tp_addr.s_addr) 281 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr; 282 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST) 283 inet->inet_saddr = 0; /* Use device */ 284 285 write_lock_bh(&l2tp_ip_lock); 286 if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0, 287 sk->sk_bound_dev_if, addr->l2tp_conn_id)) { 288 write_unlock_bh(&l2tp_ip_lock); 289 ret = -EADDRINUSE; 290 goto out; 291 } 292 293 sk_dst_reset(sk); 294 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id; 295 296 sk_add_bind_node(sk, &l2tp_ip_bind_table); 297 sk_del_node_init(sk); 298 write_unlock_bh(&l2tp_ip_lock); 299 300 ret = 0; 301 sock_reset_flag(sk, SOCK_ZAPPED); 302 303 out: 304 release_sock(sk); 305 306 return ret; 307 } 308 309 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 310 { 311 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr; 312 int rc; 313 314 if (addr_len < sizeof(*lsa)) 315 return -EINVAL; 316 317 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr)) 318 return -EINVAL; 319 320 lock_sock(sk); 321 322 /* Must bind first - autobinding does not work */ 323 if (sock_flag(sk, SOCK_ZAPPED)) { 324 rc = -EINVAL; 325 goto out_sk; 326 } 327 328 rc = __ip4_datagram_connect(sk, uaddr, addr_len); 329 if (rc < 0) 330 goto out_sk; 331 332 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 333 334 write_lock_bh(&l2tp_ip_lock); 335 hlist_del_init(&sk->sk_bind_node); 336 sk_add_bind_node(sk, &l2tp_ip_bind_table); 337 write_unlock_bh(&l2tp_ip_lock); 338 339 out_sk: 340 release_sock(sk); 341 342 return rc; 343 } 344 345 static int l2tp_ip_disconnect(struct sock *sk, int flags) 346 { 347 if (sock_flag(sk, SOCK_ZAPPED)) 348 return 0; 349 350 return __udp_disconnect(sk, flags); 351 } 352 353 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr, 354 int *uaddr_len, int peer) 355 { 356 struct sock *sk = sock->sk; 357 struct inet_sock *inet = inet_sk(sk); 358 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk); 359 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr; 360 361 memset(lsa, 0, sizeof(*lsa)); 362 lsa->l2tp_family = AF_INET; 363 if (peer) { 364 if (!inet->inet_dport) 365 return -ENOTCONN; 366 lsa->l2tp_conn_id = lsk->peer_conn_id; 367 lsa->l2tp_addr.s_addr = inet->inet_daddr; 368 } else { 369 __be32 addr = inet->inet_rcv_saddr; 370 if (!addr) 371 addr = inet->inet_saddr; 372 lsa->l2tp_conn_id = lsk->conn_id; 373 lsa->l2tp_addr.s_addr = addr; 374 } 375 *uaddr_len = sizeof(*lsa); 376 return 0; 377 } 378 379 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb) 380 { 381 int rc; 382 383 /* Charge it to the socket, dropping if the queue is full. */ 384 rc = sock_queue_rcv_skb(sk, skb); 385 if (rc < 0) 386 goto drop; 387 388 return 0; 389 390 drop: 391 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); 392 kfree_skb(skb); 393 return 0; 394 } 395 396 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 397 * control frames. 398 */ 399 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 400 { 401 struct sk_buff *skb; 402 int rc; 403 struct inet_sock *inet = inet_sk(sk); 404 struct rtable *rt = NULL; 405 struct flowi4 *fl4; 406 int connected = 0; 407 __be32 daddr; 408 409 lock_sock(sk); 410 411 rc = -ENOTCONN; 412 if (sock_flag(sk, SOCK_DEAD)) 413 goto out; 414 415 /* Get and verify the address. */ 416 if (msg->msg_name) { 417 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name); 418 rc = -EINVAL; 419 if (msg->msg_namelen < sizeof(*lip)) 420 goto out; 421 422 if (lip->l2tp_family != AF_INET) { 423 rc = -EAFNOSUPPORT; 424 if (lip->l2tp_family != AF_UNSPEC) 425 goto out; 426 } 427 428 daddr = lip->l2tp_addr.s_addr; 429 } else { 430 rc = -EDESTADDRREQ; 431 if (sk->sk_state != TCP_ESTABLISHED) 432 goto out; 433 434 daddr = inet->inet_daddr; 435 connected = 1; 436 } 437 438 /* Allocate a socket buffer */ 439 rc = -ENOMEM; 440 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) + 441 4 + len, 0, GFP_KERNEL); 442 if (!skb) 443 goto error; 444 445 /* Reserve space for headers, putting IP header on 4-byte boundary. */ 446 skb_reserve(skb, 2 + NET_SKB_PAD); 447 skb_reset_network_header(skb); 448 skb_reserve(skb, sizeof(struct iphdr)); 449 skb_reset_transport_header(skb); 450 451 /* Insert 0 session_id */ 452 *((__be32 *) skb_put(skb, 4)) = 0; 453 454 /* Copy user data into skb */ 455 rc = memcpy_from_msg(skb_put(skb, len), msg, len); 456 if (rc < 0) { 457 kfree_skb(skb); 458 goto error; 459 } 460 461 fl4 = &inet->cork.fl.u.ip4; 462 if (connected) 463 rt = (struct rtable *) __sk_dst_check(sk, 0); 464 465 rcu_read_lock(); 466 if (rt == NULL) { 467 const struct ip_options_rcu *inet_opt; 468 469 inet_opt = rcu_dereference(inet->inet_opt); 470 471 /* Use correct destination address if we have options. */ 472 if (inet_opt && inet_opt->opt.srr) 473 daddr = inet_opt->opt.faddr; 474 475 /* If this fails, retransmit mechanism of transport layer will 476 * keep trying until route appears or the connection times 477 * itself out. 478 */ 479 rt = ip_route_output_ports(sock_net(sk), fl4, sk, 480 daddr, inet->inet_saddr, 481 inet->inet_dport, inet->inet_sport, 482 sk->sk_protocol, RT_CONN_FLAGS(sk), 483 sk->sk_bound_dev_if); 484 if (IS_ERR(rt)) 485 goto no_route; 486 if (connected) { 487 sk_setup_caps(sk, &rt->dst); 488 } else { 489 skb_dst_set(skb, &rt->dst); 490 goto xmit; 491 } 492 } 493 494 /* We dont need to clone dst here, it is guaranteed to not disappear. 495 * __dev_xmit_skb() might force a refcount if needed. 496 */ 497 skb_dst_set_noref(skb, &rt->dst); 498 499 xmit: 500 /* Queue the packet to IP for output */ 501 rc = ip_queue_xmit(sk, skb, &inet->cork.fl); 502 rcu_read_unlock(); 503 504 error: 505 if (rc >= 0) 506 rc = len; 507 508 out: 509 release_sock(sk); 510 return rc; 511 512 no_route: 513 rcu_read_unlock(); 514 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 515 kfree_skb(skb); 516 rc = -EHOSTUNREACH; 517 goto out; 518 } 519 520 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg, 521 size_t len, int noblock, int flags, int *addr_len) 522 { 523 struct inet_sock *inet = inet_sk(sk); 524 size_t copied = 0; 525 int err = -EOPNOTSUPP; 526 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name); 527 struct sk_buff *skb; 528 529 if (flags & MSG_OOB) 530 goto out; 531 532 skb = skb_recv_datagram(sk, flags, noblock, &err); 533 if (!skb) 534 goto out; 535 536 copied = skb->len; 537 if (len < copied) { 538 msg->msg_flags |= MSG_TRUNC; 539 copied = len; 540 } 541 542 err = skb_copy_datagram_msg(skb, 0, msg, copied); 543 if (err) 544 goto done; 545 546 sock_recv_timestamp(msg, sk, skb); 547 548 /* Copy the address. */ 549 if (sin) { 550 sin->sin_family = AF_INET; 551 sin->sin_addr.s_addr = ip_hdr(skb)->saddr; 552 sin->sin_port = 0; 553 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero)); 554 *addr_len = sizeof(*sin); 555 } 556 if (inet->cmsg_flags) 557 ip_cmsg_recv(msg, skb); 558 if (flags & MSG_TRUNC) 559 copied = skb->len; 560 done: 561 skb_free_datagram(sk, skb); 562 out: 563 return err ? err : copied; 564 } 565 566 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg) 567 { 568 struct sk_buff *skb; 569 int amount; 570 571 switch (cmd) { 572 case SIOCOUTQ: 573 amount = sk_wmem_alloc_get(sk); 574 break; 575 case SIOCINQ: 576 spin_lock_bh(&sk->sk_receive_queue.lock); 577 skb = skb_peek(&sk->sk_receive_queue); 578 amount = skb ? skb->len : 0; 579 spin_unlock_bh(&sk->sk_receive_queue.lock); 580 break; 581 582 default: 583 return -ENOIOCTLCMD; 584 } 585 586 return put_user(amount, (int __user *)arg); 587 } 588 EXPORT_SYMBOL(l2tp_ioctl); 589 590 static struct proto l2tp_ip_prot = { 591 .name = "L2TP/IP", 592 .owner = THIS_MODULE, 593 .init = l2tp_ip_open, 594 .close = l2tp_ip_close, 595 .bind = l2tp_ip_bind, 596 .connect = l2tp_ip_connect, 597 .disconnect = l2tp_ip_disconnect, 598 .ioctl = l2tp_ioctl, 599 .destroy = l2tp_ip_destroy_sock, 600 .setsockopt = ip_setsockopt, 601 .getsockopt = ip_getsockopt, 602 .sendmsg = l2tp_ip_sendmsg, 603 .recvmsg = l2tp_ip_recvmsg, 604 .backlog_rcv = l2tp_ip_backlog_recv, 605 .hash = inet_hash, 606 .unhash = inet_unhash, 607 .obj_size = sizeof(struct l2tp_ip_sock), 608 #ifdef CONFIG_COMPAT 609 .compat_setsockopt = compat_ip_setsockopt, 610 .compat_getsockopt = compat_ip_getsockopt, 611 #endif 612 }; 613 614 static const struct proto_ops l2tp_ip_ops = { 615 .family = PF_INET, 616 .owner = THIS_MODULE, 617 .release = inet_release, 618 .bind = inet_bind, 619 .connect = inet_dgram_connect, 620 .socketpair = sock_no_socketpair, 621 .accept = sock_no_accept, 622 .getname = l2tp_ip_getname, 623 .poll = datagram_poll, 624 .ioctl = inet_ioctl, 625 .listen = sock_no_listen, 626 .shutdown = inet_shutdown, 627 .setsockopt = sock_common_setsockopt, 628 .getsockopt = sock_common_getsockopt, 629 .sendmsg = inet_sendmsg, 630 .recvmsg = sock_common_recvmsg, 631 .mmap = sock_no_mmap, 632 .sendpage = sock_no_sendpage, 633 #ifdef CONFIG_COMPAT 634 .compat_setsockopt = compat_sock_common_setsockopt, 635 .compat_getsockopt = compat_sock_common_getsockopt, 636 #endif 637 }; 638 639 static struct inet_protosw l2tp_ip_protosw = { 640 .type = SOCK_DGRAM, 641 .protocol = IPPROTO_L2TP, 642 .prot = &l2tp_ip_prot, 643 .ops = &l2tp_ip_ops, 644 }; 645 646 static struct net_protocol l2tp_ip_protocol __read_mostly = { 647 .handler = l2tp_ip_recv, 648 .netns_ok = 1, 649 }; 650 651 static int __init l2tp_ip_init(void) 652 { 653 int err; 654 655 pr_info("L2TP IP encapsulation support (L2TPv3)\n"); 656 657 err = proto_register(&l2tp_ip_prot, 1); 658 if (err != 0) 659 goto out; 660 661 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 662 if (err) 663 goto out1; 664 665 inet_register_protosw(&l2tp_ip_protosw); 666 return 0; 667 668 out1: 669 proto_unregister(&l2tp_ip_prot); 670 out: 671 return err; 672 } 673 674 static void __exit l2tp_ip_exit(void) 675 { 676 inet_unregister_protosw(&l2tp_ip_protosw); 677 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 678 proto_unregister(&l2tp_ip_prot); 679 } 680 681 module_init(l2tp_ip_init); 682 module_exit(l2tp_ip_exit); 683 684 MODULE_LICENSE("GPL"); 685 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 686 MODULE_DESCRIPTION("L2TP over IP"); 687 MODULE_VERSION("1.0"); 688 689 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like 690 * enums 691 */ 692 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP); 693 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP); 694