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 int length; 122 123 if (!pskb_may_pull(skb, 4)) 124 goto discard; 125 126 /* Point to L2TP header */ 127 optr = skb->data; 128 ptr = skb->data; 129 session_id = ntohl(*((__be32 *)ptr)); 130 ptr += 4; 131 132 /* RFC3931: L2TP/IP packets have the first 4 bytes containing 133 * the session_id. If it is 0, the packet is a L2TP control 134 * frame and the session_id value can be discarded. 135 */ 136 if (session_id == 0) { 137 __skb_pull(skb, 4); 138 goto pass_up; 139 } 140 141 /* Ok, this is a data packet. Lookup the session. */ 142 session = l2tp_session_get(net, session_id); 143 if (!session) 144 goto discard; 145 146 tunnel = session->tunnel; 147 if (!tunnel) 148 goto discard_sess; 149 150 /* Trace packet contents, if enabled */ 151 if (tunnel->debug & L2TP_MSG_DATA) { 152 length = min(32u, skb->len); 153 if (!pskb_may_pull(skb, length)) 154 goto discard_sess; 155 156 /* Point to L2TP header */ 157 optr = skb->data; 158 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_hash(struct sock *sk) 213 { 214 if (sk_unhashed(sk)) { 215 write_lock_bh(&l2tp_ip_lock); 216 sk_add_node(sk, &l2tp_ip_table); 217 write_unlock_bh(&l2tp_ip_lock); 218 } 219 return 0; 220 } 221 222 static void l2tp_ip_unhash(struct sock *sk) 223 { 224 if (sk_unhashed(sk)) 225 return; 226 write_lock_bh(&l2tp_ip_lock); 227 sk_del_node_init(sk); 228 write_unlock_bh(&l2tp_ip_lock); 229 } 230 231 static int l2tp_ip_open(struct sock *sk) 232 { 233 /* Prevent autobind. We don't have ports. */ 234 inet_sk(sk)->inet_num = IPPROTO_L2TP; 235 236 l2tp_ip_hash(sk); 237 return 0; 238 } 239 240 static void l2tp_ip_close(struct sock *sk, long timeout) 241 { 242 write_lock_bh(&l2tp_ip_lock); 243 hlist_del_init(&sk->sk_bind_node); 244 sk_del_node_init(sk); 245 write_unlock_bh(&l2tp_ip_lock); 246 sk_common_release(sk); 247 } 248 249 static void l2tp_ip_destroy_sock(struct sock *sk) 250 { 251 struct sk_buff *skb; 252 struct l2tp_tunnel *tunnel = sk->sk_user_data; 253 254 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 255 kfree_skb(skb); 256 257 if (tunnel) 258 l2tp_tunnel_delete(tunnel); 259 } 260 261 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 262 { 263 struct inet_sock *inet = inet_sk(sk); 264 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *)uaddr; 265 struct net *net = sock_net(sk); 266 int ret; 267 int chk_addr_ret; 268 269 if (addr_len < sizeof(struct sockaddr_l2tpip)) 270 return -EINVAL; 271 if (addr->l2tp_family != AF_INET) 272 return -EINVAL; 273 274 lock_sock(sk); 275 276 ret = -EINVAL; 277 if (!sock_flag(sk, SOCK_ZAPPED)) 278 goto out; 279 280 if (sk->sk_state != TCP_CLOSE) 281 goto out; 282 283 chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr); 284 ret = -EADDRNOTAVAIL; 285 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL && 286 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST) 287 goto out; 288 289 if (addr->l2tp_addr.s_addr) { 290 inet->inet_rcv_saddr = addr->l2tp_addr.s_addr; 291 inet->inet_saddr = addr->l2tp_addr.s_addr; 292 } 293 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST) 294 inet->inet_saddr = 0; /* Use device */ 295 296 write_lock_bh(&l2tp_ip_lock); 297 if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0, 298 sk->sk_bound_dev_if, addr->l2tp_conn_id)) { 299 write_unlock_bh(&l2tp_ip_lock); 300 ret = -EADDRINUSE; 301 goto out; 302 } 303 304 sk_dst_reset(sk); 305 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id; 306 307 sk_add_bind_node(sk, &l2tp_ip_bind_table); 308 sk_del_node_init(sk); 309 write_unlock_bh(&l2tp_ip_lock); 310 311 ret = 0; 312 sock_reset_flag(sk, SOCK_ZAPPED); 313 314 out: 315 release_sock(sk); 316 317 return ret; 318 } 319 320 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 321 { 322 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr; 323 int rc; 324 325 if (addr_len < sizeof(*lsa)) 326 return -EINVAL; 327 328 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr)) 329 return -EINVAL; 330 331 lock_sock(sk); 332 333 /* Must bind first - autobinding does not work */ 334 if (sock_flag(sk, SOCK_ZAPPED)) { 335 rc = -EINVAL; 336 goto out_sk; 337 } 338 339 rc = __ip4_datagram_connect(sk, uaddr, addr_len); 340 if (rc < 0) 341 goto out_sk; 342 343 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 344 345 write_lock_bh(&l2tp_ip_lock); 346 hlist_del_init(&sk->sk_bind_node); 347 sk_add_bind_node(sk, &l2tp_ip_bind_table); 348 write_unlock_bh(&l2tp_ip_lock); 349 350 out_sk: 351 release_sock(sk); 352 353 return rc; 354 } 355 356 static int l2tp_ip_disconnect(struct sock *sk, int flags) 357 { 358 if (sock_flag(sk, SOCK_ZAPPED)) 359 return 0; 360 361 return __udp_disconnect(sk, flags); 362 } 363 364 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr, 365 int peer) 366 { 367 struct sock *sk = sock->sk; 368 struct inet_sock *inet = inet_sk(sk); 369 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk); 370 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr; 371 372 memset(lsa, 0, sizeof(*lsa)); 373 lsa->l2tp_family = AF_INET; 374 if (peer) { 375 if (!inet->inet_dport) 376 return -ENOTCONN; 377 lsa->l2tp_conn_id = lsk->peer_conn_id; 378 lsa->l2tp_addr.s_addr = inet->inet_daddr; 379 } else { 380 __be32 addr = inet->inet_rcv_saddr; 381 382 if (!addr) 383 addr = inet->inet_saddr; 384 lsa->l2tp_conn_id = lsk->conn_id; 385 lsa->l2tp_addr.s_addr = addr; 386 } 387 return sizeof(*lsa); 388 } 389 390 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb) 391 { 392 int rc; 393 394 /* Charge it to the socket, dropping if the queue is full. */ 395 rc = sock_queue_rcv_skb(sk, skb); 396 if (rc < 0) 397 goto drop; 398 399 return 0; 400 401 drop: 402 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); 403 kfree_skb(skb); 404 return 0; 405 } 406 407 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 408 * control frames. 409 */ 410 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 411 { 412 struct sk_buff *skb; 413 int rc; 414 struct inet_sock *inet = inet_sk(sk); 415 struct rtable *rt = NULL; 416 struct flowi4 *fl4; 417 int connected = 0; 418 __be32 daddr; 419 420 lock_sock(sk); 421 422 rc = -ENOTCONN; 423 if (sock_flag(sk, SOCK_DEAD)) 424 goto out; 425 426 /* Get and verify the address. */ 427 if (msg->msg_name) { 428 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name); 429 430 rc = -EINVAL; 431 if (msg->msg_namelen < sizeof(*lip)) 432 goto out; 433 434 if (lip->l2tp_family != AF_INET) { 435 rc = -EAFNOSUPPORT; 436 if (lip->l2tp_family != AF_UNSPEC) 437 goto out; 438 } 439 440 daddr = lip->l2tp_addr.s_addr; 441 } else { 442 rc = -EDESTADDRREQ; 443 if (sk->sk_state != TCP_ESTABLISHED) 444 goto out; 445 446 daddr = inet->inet_daddr; 447 connected = 1; 448 } 449 450 /* Allocate a socket buffer */ 451 rc = -ENOMEM; 452 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) + 453 4 + len, 0, GFP_KERNEL); 454 if (!skb) 455 goto error; 456 457 /* Reserve space for headers, putting IP header on 4-byte boundary. */ 458 skb_reserve(skb, 2 + NET_SKB_PAD); 459 skb_reset_network_header(skb); 460 skb_reserve(skb, sizeof(struct iphdr)); 461 skb_reset_transport_header(skb); 462 463 /* Insert 0 session_id */ 464 *((__be32 *)skb_put(skb, 4)) = 0; 465 466 /* Copy user data into skb */ 467 rc = memcpy_from_msg(skb_put(skb, len), msg, len); 468 if (rc < 0) { 469 kfree_skb(skb); 470 goto error; 471 } 472 473 fl4 = &inet->cork.fl.u.ip4; 474 if (connected) 475 rt = (struct rtable *)__sk_dst_check(sk, 0); 476 477 rcu_read_lock(); 478 if (!rt) { 479 const struct ip_options_rcu *inet_opt; 480 481 inet_opt = rcu_dereference(inet->inet_opt); 482 483 /* Use correct destination address if we have options. */ 484 if (inet_opt && inet_opt->opt.srr) 485 daddr = inet_opt->opt.faddr; 486 487 /* If this fails, retransmit mechanism of transport layer will 488 * keep trying until route appears or the connection times 489 * itself out. 490 */ 491 rt = ip_route_output_ports(sock_net(sk), fl4, sk, 492 daddr, inet->inet_saddr, 493 inet->inet_dport, inet->inet_sport, 494 sk->sk_protocol, RT_CONN_FLAGS(sk), 495 sk->sk_bound_dev_if); 496 if (IS_ERR(rt)) 497 goto no_route; 498 if (connected) { 499 sk_setup_caps(sk, &rt->dst); 500 } else { 501 skb_dst_set(skb, &rt->dst); 502 goto xmit; 503 } 504 } 505 506 /* We dont need to clone dst here, it is guaranteed to not disappear. 507 * __dev_xmit_skb() might force a refcount if needed. 508 */ 509 skb_dst_set_noref(skb, &rt->dst); 510 511 xmit: 512 /* Queue the packet to IP for output */ 513 rc = ip_queue_xmit(sk, skb, &inet->cork.fl); 514 rcu_read_unlock(); 515 516 error: 517 if (rc >= 0) 518 rc = len; 519 520 out: 521 release_sock(sk); 522 return rc; 523 524 no_route: 525 rcu_read_unlock(); 526 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 527 kfree_skb(skb); 528 rc = -EHOSTUNREACH; 529 goto out; 530 } 531 532 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg, 533 size_t len, int noblock, int flags, int *addr_len) 534 { 535 struct inet_sock *inet = inet_sk(sk); 536 size_t copied = 0; 537 int err = -EOPNOTSUPP; 538 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name); 539 struct sk_buff *skb; 540 541 if (flags & MSG_OOB) 542 goto out; 543 544 skb = skb_recv_datagram(sk, flags, noblock, &err); 545 if (!skb) 546 goto out; 547 548 copied = skb->len; 549 if (len < copied) { 550 msg->msg_flags |= MSG_TRUNC; 551 copied = len; 552 } 553 554 err = skb_copy_datagram_msg(skb, 0, msg, copied); 555 if (err) 556 goto done; 557 558 sock_recv_timestamp(msg, sk, skb); 559 560 /* Copy the address. */ 561 if (sin) { 562 sin->sin_family = AF_INET; 563 sin->sin_addr.s_addr = ip_hdr(skb)->saddr; 564 sin->sin_port = 0; 565 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero)); 566 *addr_len = sizeof(*sin); 567 } 568 if (inet->cmsg_flags) 569 ip_cmsg_recv(msg, skb); 570 if (flags & MSG_TRUNC) 571 copied = skb->len; 572 done: 573 skb_free_datagram(sk, skb); 574 out: 575 return err ? err : copied; 576 } 577 578 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg) 579 { 580 struct sk_buff *skb; 581 int amount; 582 583 switch (cmd) { 584 case SIOCOUTQ: 585 amount = sk_wmem_alloc_get(sk); 586 break; 587 case SIOCINQ: 588 spin_lock_bh(&sk->sk_receive_queue.lock); 589 skb = skb_peek(&sk->sk_receive_queue); 590 amount = skb ? skb->len : 0; 591 spin_unlock_bh(&sk->sk_receive_queue.lock); 592 break; 593 594 default: 595 return -ENOIOCTLCMD; 596 } 597 598 return put_user(amount, (int __user *)arg); 599 } 600 EXPORT_SYMBOL_GPL(l2tp_ioctl); 601 602 static struct proto l2tp_ip_prot = { 603 .name = "L2TP/IP", 604 .owner = THIS_MODULE, 605 .init = l2tp_ip_open, 606 .close = l2tp_ip_close, 607 .bind = l2tp_ip_bind, 608 .connect = l2tp_ip_connect, 609 .disconnect = l2tp_ip_disconnect, 610 .ioctl = l2tp_ioctl, 611 .destroy = l2tp_ip_destroy_sock, 612 .setsockopt = ip_setsockopt, 613 .getsockopt = ip_getsockopt, 614 .sendmsg = l2tp_ip_sendmsg, 615 .recvmsg = l2tp_ip_recvmsg, 616 .backlog_rcv = l2tp_ip_backlog_recv, 617 .hash = l2tp_ip_hash, 618 .unhash = l2tp_ip_unhash, 619 .obj_size = sizeof(struct l2tp_ip_sock), 620 }; 621 622 static const struct proto_ops l2tp_ip_ops = { 623 .family = PF_INET, 624 .owner = THIS_MODULE, 625 .release = inet_release, 626 .bind = inet_bind, 627 .connect = inet_dgram_connect, 628 .socketpair = sock_no_socketpair, 629 .accept = sock_no_accept, 630 .getname = l2tp_ip_getname, 631 .poll = datagram_poll, 632 .ioctl = inet_ioctl, 633 .gettstamp = sock_gettstamp, 634 .listen = sock_no_listen, 635 .shutdown = inet_shutdown, 636 .setsockopt = sock_common_setsockopt, 637 .getsockopt = sock_common_getsockopt, 638 .sendmsg = inet_sendmsg, 639 .recvmsg = sock_common_recvmsg, 640 .mmap = sock_no_mmap, 641 .sendpage = sock_no_sendpage, 642 }; 643 644 static struct inet_protosw l2tp_ip_protosw = { 645 .type = SOCK_DGRAM, 646 .protocol = IPPROTO_L2TP, 647 .prot = &l2tp_ip_prot, 648 .ops = &l2tp_ip_ops, 649 }; 650 651 static struct net_protocol l2tp_ip_protocol __read_mostly = { 652 .handler = l2tp_ip_recv, 653 .netns_ok = 1, 654 }; 655 656 static int __init l2tp_ip_init(void) 657 { 658 int err; 659 660 pr_info("L2TP IP encapsulation support (L2TPv3)\n"); 661 662 err = proto_register(&l2tp_ip_prot, 1); 663 if (err != 0) 664 goto out; 665 666 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 667 if (err) 668 goto out1; 669 670 inet_register_protosw(&l2tp_ip_protosw); 671 return 0; 672 673 out1: 674 proto_unregister(&l2tp_ip_prot); 675 out: 676 return err; 677 } 678 679 static void __exit l2tp_ip_exit(void) 680 { 681 inet_unregister_protosw(&l2tp_ip_protosw); 682 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 683 proto_unregister(&l2tp_ip_prot); 684 } 685 686 module_init(l2tp_ip_init); 687 module_exit(l2tp_ip_exit); 688 689 MODULE_LICENSE("GPL"); 690 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 691 MODULE_DESCRIPTION("L2TP over IP"); 692 MODULE_VERSION("1.0"); 693 694 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like 695 * enums 696 */ 697 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP); 698 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP); 699