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 #include <linux/icmp.h> 13 #include <linux/module.h> 14 #include <linux/skbuff.h> 15 #include <linux/random.h> 16 #include <linux/socket.h> 17 #include <linux/l2tp.h> 18 #include <linux/in.h> 19 #include <net/sock.h> 20 #include <net/ip.h> 21 #include <net/icmp.h> 22 #include <net/udp.h> 23 #include <net/inet_common.h> 24 #include <net/inet_hashtables.h> 25 #include <net/tcp_states.h> 26 #include <net/protocol.h> 27 #include <net/xfrm.h> 28 29 #include "l2tp_core.h" 30 31 struct l2tp_ip_sock { 32 /* inet_sock has to be the first member of l2tp_ip_sock */ 33 struct inet_sock inet; 34 35 __u32 conn_id; 36 __u32 peer_conn_id; 37 38 __u64 tx_packets; 39 __u64 tx_bytes; 40 __u64 tx_errors; 41 __u64 rx_packets; 42 __u64 rx_bytes; 43 __u64 rx_errors; 44 }; 45 46 static DEFINE_RWLOCK(l2tp_ip_lock); 47 static struct hlist_head l2tp_ip_table; 48 static struct hlist_head l2tp_ip_bind_table; 49 50 static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk) 51 { 52 return (struct l2tp_ip_sock *)sk; 53 } 54 55 static struct sock *__l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id) 56 { 57 struct hlist_node *node; 58 struct sock *sk; 59 60 sk_for_each_bound(sk, node, &l2tp_ip_bind_table) { 61 struct inet_sock *inet = inet_sk(sk); 62 struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk); 63 64 if (l2tp == NULL) 65 continue; 66 67 if ((l2tp->conn_id == tunnel_id) && 68 #ifdef CONFIG_NET_NS 69 (sk->sk_net == net) && 70 #endif 71 !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) && 72 !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)) 73 goto found; 74 } 75 76 sk = NULL; 77 found: 78 return sk; 79 } 80 81 static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id) 82 { 83 struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id); 84 if (sk) 85 sock_hold(sk); 86 87 return sk; 88 } 89 90 /* When processing receive frames, there are two cases to 91 * consider. Data frames consist of a non-zero session-id and an 92 * optional cookie. Control frames consist of a regular L2TP header 93 * preceded by 32-bits of zeros. 94 * 95 * L2TPv3 Session 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 * | Session ID | 101 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 102 * | Cookie (optional, maximum 64 bits)... 103 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 104 * | 105 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 106 * 107 * L2TPv3 Control Message Header Over IP 108 * 109 * 0 1 2 3 110 * 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 1 111 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 112 * | (32 bits of zeros) | 113 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 114 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length | 115 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 116 * | Control Connection ID | 117 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 118 * | Ns | Nr | 119 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 120 * 121 * All control frames are passed to userspace. 122 */ 123 static int l2tp_ip_recv(struct sk_buff *skb) 124 { 125 struct sock *sk; 126 u32 session_id; 127 u32 tunnel_id; 128 unsigned char *ptr, *optr; 129 struct l2tp_session *session; 130 struct l2tp_tunnel *tunnel = NULL; 131 int length; 132 int offset; 133 134 /* Point to L2TP header */ 135 optr = ptr = skb->data; 136 137 if (!pskb_may_pull(skb, 4)) 138 goto discard; 139 140 session_id = ntohl(*((__be32 *) ptr)); 141 ptr += 4; 142 143 /* RFC3931: L2TP/IP packets have the first 4 bytes containing 144 * the session_id. If it is 0, the packet is a L2TP control 145 * frame and the session_id value can be discarded. 146 */ 147 if (session_id == 0) { 148 __skb_pull(skb, 4); 149 goto pass_up; 150 } 151 152 /* Ok, this is a data packet. Lookup the session. */ 153 session = l2tp_session_find(&init_net, NULL, session_id); 154 if (session == NULL) 155 goto discard; 156 157 tunnel = session->tunnel; 158 if (tunnel == NULL) 159 goto discard; 160 161 /* Trace packet contents, if enabled */ 162 if (tunnel->debug & L2TP_MSG_DATA) { 163 length = min(32u, skb->len); 164 if (!pskb_may_pull(skb, length)) 165 goto discard; 166 167 printk(KERN_DEBUG "%s: ip recv: ", tunnel->name); 168 169 offset = 0; 170 do { 171 printk(" %02X", ptr[offset]); 172 } while (++offset < length); 173 174 printk("\n"); 175 } 176 177 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook); 178 179 return 0; 180 181 pass_up: 182 /* Get the tunnel_id from the L2TP header */ 183 if (!pskb_may_pull(skb, 12)) 184 goto discard; 185 186 if ((skb->data[0] & 0xc0) != 0xc0) 187 goto discard; 188 189 tunnel_id = ntohl(*(__be32 *) &skb->data[4]); 190 tunnel = l2tp_tunnel_find(&init_net, tunnel_id); 191 if (tunnel != NULL) 192 sk = tunnel->sock; 193 else { 194 struct iphdr *iph = (struct iphdr *) skb_network_header(skb); 195 196 read_lock_bh(&l2tp_ip_lock); 197 sk = __l2tp_ip_bind_lookup(&init_net, iph->daddr, 0, tunnel_id); 198 read_unlock_bh(&l2tp_ip_lock); 199 } 200 201 if (sk == NULL) 202 goto discard; 203 204 sock_hold(sk); 205 206 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 207 goto discard_put; 208 209 nf_reset(skb); 210 211 return sk_receive_skb(sk, skb, 1); 212 213 discard_put: 214 sock_put(sk); 215 216 discard: 217 kfree_skb(skb); 218 return 0; 219 } 220 221 static int l2tp_ip_open(struct sock *sk) 222 { 223 /* Prevent autobind. We don't have ports. */ 224 inet_sk(sk)->inet_num = IPPROTO_L2TP; 225 226 write_lock_bh(&l2tp_ip_lock); 227 sk_add_node(sk, &l2tp_ip_table); 228 write_unlock_bh(&l2tp_ip_lock); 229 230 return 0; 231 } 232 233 static void l2tp_ip_close(struct sock *sk, long timeout) 234 { 235 write_lock_bh(&l2tp_ip_lock); 236 hlist_del_init(&sk->sk_bind_node); 237 hlist_del_init(&sk->sk_node); 238 write_unlock_bh(&l2tp_ip_lock); 239 sk_common_release(sk); 240 } 241 242 static void l2tp_ip_destroy_sock(struct sock *sk) 243 { 244 struct sk_buff *skb; 245 246 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 247 kfree_skb(skb); 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 int ret = -EINVAL; 257 int chk_addr_ret; 258 259 ret = -EADDRINUSE; 260 read_lock_bh(&l2tp_ip_lock); 261 if (__l2tp_ip_bind_lookup(&init_net, addr->l2tp_addr.s_addr, sk->sk_bound_dev_if, addr->l2tp_conn_id)) 262 goto out_in_use; 263 264 read_unlock_bh(&l2tp_ip_lock); 265 266 lock_sock(sk); 267 if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip)) 268 goto out; 269 270 chk_addr_ret = inet_addr_type(&init_net, addr->l2tp_addr.s_addr); 271 ret = -EADDRNOTAVAIL; 272 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL && 273 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST) 274 goto out; 275 276 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr; 277 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST) 278 inet->inet_saddr = 0; /* Use device */ 279 sk_dst_reset(sk); 280 281 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id; 282 283 write_lock_bh(&l2tp_ip_lock); 284 sk_add_bind_node(sk, &l2tp_ip_bind_table); 285 sk_del_node_init(sk); 286 write_unlock_bh(&l2tp_ip_lock); 287 ret = 0; 288 out: 289 release_sock(sk); 290 291 return ret; 292 293 out_in_use: 294 read_unlock_bh(&l2tp_ip_lock); 295 296 return ret; 297 } 298 299 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 300 { 301 int rc; 302 struct inet_sock *inet = inet_sk(sk); 303 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr; 304 struct rtable *rt; 305 __be32 saddr; 306 int oif; 307 308 rc = -EINVAL; 309 if (addr_len < sizeof(*lsa)) 310 goto out; 311 312 rc = -EAFNOSUPPORT; 313 if (lsa->l2tp_family != AF_INET) 314 goto out; 315 316 sk_dst_reset(sk); 317 318 oif = sk->sk_bound_dev_if; 319 saddr = inet->inet_saddr; 320 321 rc = -EINVAL; 322 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr)) 323 goto out; 324 325 rc = ip_route_connect(&rt, lsa->l2tp_addr.s_addr, saddr, 326 RT_CONN_FLAGS(sk), oif, 327 IPPROTO_L2TP, 328 0, 0, sk, 1); 329 if (rc) { 330 if (rc == -ENETUNREACH) 331 IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES); 332 goto out; 333 } 334 335 rc = -ENETUNREACH; 336 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { 337 ip_rt_put(rt); 338 goto out; 339 } 340 341 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 342 343 if (!inet->inet_saddr) 344 inet->inet_saddr = rt->rt_src; 345 if (!inet->inet_rcv_saddr) 346 inet->inet_rcv_saddr = rt->rt_src; 347 inet->inet_daddr = rt->rt_dst; 348 sk->sk_state = TCP_ESTABLISHED; 349 inet->inet_id = jiffies; 350 351 sk_dst_set(sk, &rt->dst); 352 353 write_lock_bh(&l2tp_ip_lock); 354 hlist_del_init(&sk->sk_bind_node); 355 sk_add_bind_node(sk, &l2tp_ip_bind_table); 356 write_unlock_bh(&l2tp_ip_lock); 357 358 rc = 0; 359 out: 360 return rc; 361 } 362 363 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr, 364 int *uaddr_len, int peer) 365 { 366 struct sock *sk = sock->sk; 367 struct inet_sock *inet = inet_sk(sk); 368 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk); 369 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr; 370 371 memset(lsa, 0, sizeof(*lsa)); 372 lsa->l2tp_family = AF_INET; 373 if (peer) { 374 if (!inet->inet_dport) 375 return -ENOTCONN; 376 lsa->l2tp_conn_id = lsk->peer_conn_id; 377 lsa->l2tp_addr.s_addr = inet->inet_daddr; 378 } else { 379 __be32 addr = inet->inet_rcv_saddr; 380 if (!addr) 381 addr = inet->inet_saddr; 382 lsa->l2tp_conn_id = lsk->conn_id; 383 lsa->l2tp_addr.s_addr = addr; 384 } 385 *uaddr_len = sizeof(*lsa); 386 return 0; 387 } 388 389 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb) 390 { 391 int rc; 392 393 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 394 goto drop; 395 396 nf_reset(skb); 397 398 /* Charge it to the socket, dropping if the queue is full. */ 399 rc = sock_queue_rcv_skb(sk, skb); 400 if (rc < 0) 401 goto drop; 402 403 return 0; 404 405 drop: 406 IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS); 407 kfree_skb(skb); 408 return -1; 409 } 410 411 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 412 * control frames. 413 */ 414 static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len) 415 { 416 struct sk_buff *skb; 417 int rc; 418 struct l2tp_ip_sock *lsa = l2tp_ip_sk(sk); 419 struct inet_sock *inet = inet_sk(sk); 420 struct ip_options *opt = inet->opt; 421 struct rtable *rt = NULL; 422 int connected = 0; 423 __be32 daddr; 424 425 if (sock_flag(sk, SOCK_DEAD)) 426 return -ENOTCONN; 427 428 /* Get and verify the address. */ 429 if (msg->msg_name) { 430 struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name; 431 if (msg->msg_namelen < sizeof(*lip)) 432 return -EINVAL; 433 434 if (lip->l2tp_family != AF_INET) { 435 if (lip->l2tp_family != AF_UNSPEC) 436 return -EAFNOSUPPORT; 437 } 438 439 daddr = lip->l2tp_addr.s_addr; 440 } else { 441 if (sk->sk_state != TCP_ESTABLISHED) 442 return -EDESTADDRREQ; 443 444 daddr = inet->inet_daddr; 445 connected = 1; 446 } 447 448 /* Allocate a socket buffer */ 449 rc = -ENOMEM; 450 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) + 451 4 + len, 0, GFP_KERNEL); 452 if (!skb) 453 goto error; 454 455 /* Reserve space for headers, putting IP header on 4-byte boundary. */ 456 skb_reserve(skb, 2 + NET_SKB_PAD); 457 skb_reset_network_header(skb); 458 skb_reserve(skb, sizeof(struct iphdr)); 459 skb_reset_transport_header(skb); 460 461 /* Insert 0 session_id */ 462 *((__be32 *) skb_put(skb, 4)) = 0; 463 464 /* Copy user data into skb */ 465 rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len); 466 if (rc < 0) { 467 kfree_skb(skb); 468 goto error; 469 } 470 471 if (connected) 472 rt = (struct rtable *) __sk_dst_check(sk, 0); 473 474 if (rt == NULL) { 475 /* Use correct destination address if we have options. */ 476 if (opt && opt->srr) 477 daddr = opt->faddr; 478 479 { 480 struct flowi fl = { .oif = sk->sk_bound_dev_if, 481 .nl_u = { .ip4_u = { 482 .daddr = daddr, 483 .saddr = inet->inet_saddr, 484 .tos = RT_CONN_FLAGS(sk) } }, 485 .proto = sk->sk_protocol, 486 .flags = inet_sk_flowi_flags(sk), 487 .uli_u = { .ports = { 488 .sport = inet->inet_sport, 489 .dport = inet->inet_dport } } }; 490 491 /* If this fails, retransmit mechanism of transport layer will 492 * keep trying until route appears or the connection times 493 * itself out. 494 */ 495 security_sk_classify_flow(sk, &fl); 496 if (ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 0)) 497 goto no_route; 498 } 499 sk_setup_caps(sk, &rt->dst); 500 } 501 skb_dst_set(skb, dst_clone(&rt->dst)); 502 503 /* Queue the packet to IP for output */ 504 rc = ip_queue_xmit(skb); 505 506 error: 507 /* Update stats */ 508 if (rc >= 0) { 509 lsa->tx_packets++; 510 lsa->tx_bytes += len; 511 rc = len; 512 } else { 513 lsa->tx_errors++; 514 } 515 516 return rc; 517 518 no_route: 519 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 520 kfree_skb(skb); 521 return -EHOSTUNREACH; 522 } 523 524 static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 525 size_t len, int noblock, int flags, int *addr_len) 526 { 527 struct inet_sock *inet = inet_sk(sk); 528 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk); 529 size_t copied = 0; 530 int err = -EOPNOTSUPP; 531 struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name; 532 struct sk_buff *skb; 533 534 if (flags & MSG_OOB) 535 goto out; 536 537 if (addr_len) 538 *addr_len = sizeof(*sin); 539 540 skb = skb_recv_datagram(sk, flags, noblock, &err); 541 if (!skb) 542 goto out; 543 544 copied = skb->len; 545 if (len < copied) { 546 msg->msg_flags |= MSG_TRUNC; 547 copied = len; 548 } 549 550 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied); 551 if (err) 552 goto done; 553 554 sock_recv_timestamp(msg, sk, skb); 555 556 /* Copy the address. */ 557 if (sin) { 558 sin->sin_family = AF_INET; 559 sin->sin_addr.s_addr = ip_hdr(skb)->saddr; 560 sin->sin_port = 0; 561 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero)); 562 } 563 if (inet->cmsg_flags) 564 ip_cmsg_recv(msg, skb); 565 if (flags & MSG_TRUNC) 566 copied = skb->len; 567 done: 568 skb_free_datagram(sk, skb); 569 out: 570 if (err) { 571 lsk->rx_errors++; 572 return err; 573 } 574 575 lsk->rx_packets++; 576 lsk->rx_bytes += copied; 577 578 return copied; 579 } 580 581 struct proto l2tp_ip_prot = { 582 .name = "L2TP/IP", 583 .owner = THIS_MODULE, 584 .init = l2tp_ip_open, 585 .close = l2tp_ip_close, 586 .bind = l2tp_ip_bind, 587 .connect = l2tp_ip_connect, 588 .disconnect = udp_disconnect, 589 .ioctl = udp_ioctl, 590 .destroy = l2tp_ip_destroy_sock, 591 .setsockopt = ip_setsockopt, 592 .getsockopt = ip_getsockopt, 593 .sendmsg = l2tp_ip_sendmsg, 594 .recvmsg = l2tp_ip_recvmsg, 595 .backlog_rcv = l2tp_ip_backlog_recv, 596 .hash = inet_hash, 597 .unhash = inet_unhash, 598 .obj_size = sizeof(struct l2tp_ip_sock), 599 #ifdef CONFIG_COMPAT 600 .compat_setsockopt = compat_ip_setsockopt, 601 .compat_getsockopt = compat_ip_getsockopt, 602 #endif 603 }; 604 605 static const struct proto_ops l2tp_ip_ops = { 606 .family = PF_INET, 607 .owner = THIS_MODULE, 608 .release = inet_release, 609 .bind = inet_bind, 610 .connect = inet_dgram_connect, 611 .socketpair = sock_no_socketpair, 612 .accept = sock_no_accept, 613 .getname = l2tp_ip_getname, 614 .poll = datagram_poll, 615 .ioctl = inet_ioctl, 616 .listen = sock_no_listen, 617 .shutdown = inet_shutdown, 618 .setsockopt = sock_common_setsockopt, 619 .getsockopt = sock_common_getsockopt, 620 .sendmsg = inet_sendmsg, 621 .recvmsg = sock_common_recvmsg, 622 .mmap = sock_no_mmap, 623 .sendpage = sock_no_sendpage, 624 #ifdef CONFIG_COMPAT 625 .compat_setsockopt = compat_sock_common_setsockopt, 626 .compat_getsockopt = compat_sock_common_getsockopt, 627 #endif 628 }; 629 630 static struct inet_protosw l2tp_ip_protosw = { 631 .type = SOCK_DGRAM, 632 .protocol = IPPROTO_L2TP, 633 .prot = &l2tp_ip_prot, 634 .ops = &l2tp_ip_ops, 635 .no_check = 0, 636 }; 637 638 static struct net_protocol l2tp_ip_protocol __read_mostly = { 639 .handler = l2tp_ip_recv, 640 }; 641 642 static int __init l2tp_ip_init(void) 643 { 644 int err; 645 646 printk(KERN_INFO "L2TP IP encapsulation support (L2TPv3)\n"); 647 648 err = proto_register(&l2tp_ip_prot, 1); 649 if (err != 0) 650 goto out; 651 652 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 653 if (err) 654 goto out1; 655 656 inet_register_protosw(&l2tp_ip_protosw); 657 return 0; 658 659 out1: 660 proto_unregister(&l2tp_ip_prot); 661 out: 662 return err; 663 } 664 665 static void __exit l2tp_ip_exit(void) 666 { 667 inet_unregister_protosw(&l2tp_ip_protosw); 668 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 669 proto_unregister(&l2tp_ip_prot); 670 } 671 672 module_init(l2tp_ip_init); 673 module_exit(l2tp_ip_exit); 674 675 MODULE_LICENSE("GPL"); 676 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 677 MODULE_DESCRIPTION("L2TP over IP"); 678 MODULE_VERSION("1.0"); 679 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, SOCK_DGRAM, IPPROTO_L2TP); 680