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, session_id); 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 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) 169 goto discard_sess; 170 171 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len); 172 l2tp_session_dec_refcount(session); 173 174 return 0; 175 176 pass_up: 177 /* Get the tunnel_id from the L2TP header */ 178 if (!pskb_may_pull(skb, 12)) 179 goto discard; 180 181 if ((skb->data[0] & 0xc0) != 0xc0) 182 goto discard; 183 184 tunnel_id = ntohl(*(__be32 *) &skb->data[4]); 185 iph = (struct iphdr *)skb_network_header(skb); 186 187 read_lock_bh(&l2tp_ip_lock); 188 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb), 189 tunnel_id); 190 if (!sk) { 191 read_unlock_bh(&l2tp_ip_lock); 192 goto discard; 193 } 194 sock_hold(sk); 195 read_unlock_bh(&l2tp_ip_lock); 196 197 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 198 goto discard_put; 199 200 nf_reset(skb); 201 202 return sk_receive_skb(sk, skb, 1); 203 204 discard_sess: 205 l2tp_session_dec_refcount(session); 206 goto discard; 207 208 discard_put: 209 sock_put(sk); 210 211 discard: 212 kfree_skb(skb); 213 return 0; 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 write_lock_bh(&l2tp_ip_lock); 222 sk_add_node(sk, &l2tp_ip_table); 223 write_unlock_bh(&l2tp_ip_lock); 224 225 return 0; 226 } 227 228 static void l2tp_ip_close(struct sock *sk, long timeout) 229 { 230 write_lock_bh(&l2tp_ip_lock); 231 hlist_del_init(&sk->sk_bind_node); 232 sk_del_node_init(sk); 233 write_unlock_bh(&l2tp_ip_lock); 234 sk_common_release(sk); 235 } 236 237 static void l2tp_ip_destroy_sock(struct sock *sk) 238 { 239 struct sk_buff *skb; 240 struct l2tp_tunnel *tunnel = sk->sk_user_data; 241 242 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 243 kfree_skb(skb); 244 245 if (tunnel) 246 l2tp_tunnel_delete(tunnel); 247 } 248 249 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 250 { 251 struct inet_sock *inet = inet_sk(sk); 252 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr; 253 struct net *net = sock_net(sk); 254 int ret; 255 int chk_addr_ret; 256 257 if (addr_len < sizeof(struct sockaddr_l2tpip)) 258 return -EINVAL; 259 if (addr->l2tp_family != AF_INET) 260 return -EINVAL; 261 262 lock_sock(sk); 263 264 ret = -EINVAL; 265 if (!sock_flag(sk, SOCK_ZAPPED)) 266 goto out; 267 268 if (sk->sk_state != TCP_CLOSE) 269 goto out; 270 271 chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr); 272 ret = -EADDRNOTAVAIL; 273 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL && 274 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST) 275 goto out; 276 277 if (addr->l2tp_addr.s_addr) 278 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr; 279 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST) 280 inet->inet_saddr = 0; /* Use device */ 281 282 write_lock_bh(&l2tp_ip_lock); 283 if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0, 284 sk->sk_bound_dev_if, addr->l2tp_conn_id)) { 285 write_unlock_bh(&l2tp_ip_lock); 286 ret = -EADDRINUSE; 287 goto out; 288 } 289 290 sk_dst_reset(sk); 291 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id; 292 293 sk_add_bind_node(sk, &l2tp_ip_bind_table); 294 sk_del_node_init(sk); 295 write_unlock_bh(&l2tp_ip_lock); 296 297 ret = 0; 298 sock_reset_flag(sk, SOCK_ZAPPED); 299 300 out: 301 release_sock(sk); 302 303 return ret; 304 } 305 306 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 307 { 308 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr; 309 int rc; 310 311 if (addr_len < sizeof(*lsa)) 312 return -EINVAL; 313 314 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr)) 315 return -EINVAL; 316 317 lock_sock(sk); 318 319 /* Must bind first - autobinding does not work */ 320 if (sock_flag(sk, SOCK_ZAPPED)) { 321 rc = -EINVAL; 322 goto out_sk; 323 } 324 325 rc = __ip4_datagram_connect(sk, uaddr, addr_len); 326 if (rc < 0) 327 goto out_sk; 328 329 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 330 331 write_lock_bh(&l2tp_ip_lock); 332 hlist_del_init(&sk->sk_bind_node); 333 sk_add_bind_node(sk, &l2tp_ip_bind_table); 334 write_unlock_bh(&l2tp_ip_lock); 335 336 out_sk: 337 release_sock(sk); 338 339 return rc; 340 } 341 342 static int l2tp_ip_disconnect(struct sock *sk, int flags) 343 { 344 if (sock_flag(sk, SOCK_ZAPPED)) 345 return 0; 346 347 return __udp_disconnect(sk, flags); 348 } 349 350 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr, 351 int peer) 352 { 353 struct sock *sk = sock->sk; 354 struct inet_sock *inet = inet_sk(sk); 355 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk); 356 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr; 357 358 memset(lsa, 0, sizeof(*lsa)); 359 lsa->l2tp_family = AF_INET; 360 if (peer) { 361 if (!inet->inet_dport) 362 return -ENOTCONN; 363 lsa->l2tp_conn_id = lsk->peer_conn_id; 364 lsa->l2tp_addr.s_addr = inet->inet_daddr; 365 } else { 366 __be32 addr = inet->inet_rcv_saddr; 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 rc = -EINVAL; 415 if (msg->msg_namelen < sizeof(*lip)) 416 goto out; 417 418 if (lip->l2tp_family != AF_INET) { 419 rc = -EAFNOSUPPORT; 420 if (lip->l2tp_family != AF_UNSPEC) 421 goto out; 422 } 423 424 daddr = lip->l2tp_addr.s_addr; 425 } else { 426 rc = -EDESTADDRREQ; 427 if (sk->sk_state != TCP_ESTABLISHED) 428 goto out; 429 430 daddr = inet->inet_daddr; 431 connected = 1; 432 } 433 434 /* Allocate a socket buffer */ 435 rc = -ENOMEM; 436 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) + 437 4 + len, 0, GFP_KERNEL); 438 if (!skb) 439 goto error; 440 441 /* Reserve space for headers, putting IP header on 4-byte boundary. */ 442 skb_reserve(skb, 2 + NET_SKB_PAD); 443 skb_reset_network_header(skb); 444 skb_reserve(skb, sizeof(struct iphdr)); 445 skb_reset_transport_header(skb); 446 447 /* Insert 0 session_id */ 448 *((__be32 *) skb_put(skb, 4)) = 0; 449 450 /* Copy user data into skb */ 451 rc = memcpy_from_msg(skb_put(skb, len), msg, len); 452 if (rc < 0) { 453 kfree_skb(skb); 454 goto error; 455 } 456 457 fl4 = &inet->cork.fl.u.ip4; 458 if (connected) 459 rt = (struct rtable *) __sk_dst_check(sk, 0); 460 461 rcu_read_lock(); 462 if (rt == NULL) { 463 const struct ip_options_rcu *inet_opt; 464 465 inet_opt = rcu_dereference(inet->inet_opt); 466 467 /* Use correct destination address if we have options. */ 468 if (inet_opt && inet_opt->opt.srr) 469 daddr = inet_opt->opt.faddr; 470 471 /* If this fails, retransmit mechanism of transport layer will 472 * keep trying until route appears or the connection times 473 * itself out. 474 */ 475 rt = ip_route_output_ports(sock_net(sk), fl4, sk, 476 daddr, inet->inet_saddr, 477 inet->inet_dport, inet->inet_sport, 478 sk->sk_protocol, RT_CONN_FLAGS(sk), 479 sk->sk_bound_dev_if); 480 if (IS_ERR(rt)) 481 goto no_route; 482 if (connected) { 483 sk_setup_caps(sk, &rt->dst); 484 } else { 485 skb_dst_set(skb, &rt->dst); 486 goto xmit; 487 } 488 } 489 490 /* We dont need to clone dst here, it is guaranteed to not disappear. 491 * __dev_xmit_skb() might force a refcount if needed. 492 */ 493 skb_dst_set_noref(skb, &rt->dst); 494 495 xmit: 496 /* Queue the packet to IP for output */ 497 rc = ip_queue_xmit(sk, skb, &inet->cork.fl); 498 rcu_read_unlock(); 499 500 error: 501 if (rc >= 0) 502 rc = len; 503 504 out: 505 release_sock(sk); 506 return rc; 507 508 no_route: 509 rcu_read_unlock(); 510 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 511 kfree_skb(skb); 512 rc = -EHOSTUNREACH; 513 goto out; 514 } 515 516 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg, 517 size_t len, int noblock, int flags, int *addr_len) 518 { 519 struct inet_sock *inet = inet_sk(sk); 520 size_t copied = 0; 521 int err = -EOPNOTSUPP; 522 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name); 523 struct sk_buff *skb; 524 525 if (flags & MSG_OOB) 526 goto out; 527 528 skb = skb_recv_datagram(sk, flags, noblock, &err); 529 if (!skb) 530 goto out; 531 532 copied = skb->len; 533 if (len < copied) { 534 msg->msg_flags |= MSG_TRUNC; 535 copied = len; 536 } 537 538 err = skb_copy_datagram_msg(skb, 0, msg, copied); 539 if (err) 540 goto done; 541 542 sock_recv_timestamp(msg, sk, skb); 543 544 /* Copy the address. */ 545 if (sin) { 546 sin->sin_family = AF_INET; 547 sin->sin_addr.s_addr = ip_hdr(skb)->saddr; 548 sin->sin_port = 0; 549 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero)); 550 *addr_len = sizeof(*sin); 551 } 552 if (inet->cmsg_flags) 553 ip_cmsg_recv(msg, skb); 554 if (flags & MSG_TRUNC) 555 copied = skb->len; 556 done: 557 skb_free_datagram(sk, skb); 558 out: 559 return err ? err : copied; 560 } 561 562 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg) 563 { 564 struct sk_buff *skb; 565 int amount; 566 567 switch (cmd) { 568 case SIOCOUTQ: 569 amount = sk_wmem_alloc_get(sk); 570 break; 571 case SIOCINQ: 572 spin_lock_bh(&sk->sk_receive_queue.lock); 573 skb = skb_peek(&sk->sk_receive_queue); 574 amount = skb ? skb->len : 0; 575 spin_unlock_bh(&sk->sk_receive_queue.lock); 576 break; 577 578 default: 579 return -ENOIOCTLCMD; 580 } 581 582 return put_user(amount, (int __user *)arg); 583 } 584 EXPORT_SYMBOL(l2tp_ioctl); 585 586 static struct proto l2tp_ip_prot = { 587 .name = "L2TP/IP", 588 .owner = THIS_MODULE, 589 .init = l2tp_ip_open, 590 .close = l2tp_ip_close, 591 .bind = l2tp_ip_bind, 592 .connect = l2tp_ip_connect, 593 .disconnect = l2tp_ip_disconnect, 594 .ioctl = l2tp_ioctl, 595 .destroy = l2tp_ip_destroy_sock, 596 .setsockopt = ip_setsockopt, 597 .getsockopt = ip_getsockopt, 598 .sendmsg = l2tp_ip_sendmsg, 599 .recvmsg = l2tp_ip_recvmsg, 600 .backlog_rcv = l2tp_ip_backlog_recv, 601 .hash = inet_hash, 602 .unhash = inet_unhash, 603 .obj_size = sizeof(struct l2tp_ip_sock), 604 #ifdef CONFIG_COMPAT 605 .compat_setsockopt = compat_ip_setsockopt, 606 .compat_getsockopt = compat_ip_getsockopt, 607 #endif 608 }; 609 610 static const struct proto_ops l2tp_ip_ops = { 611 .family = PF_INET, 612 .owner = THIS_MODULE, 613 .release = inet_release, 614 .bind = inet_bind, 615 .connect = inet_dgram_connect, 616 .socketpair = sock_no_socketpair, 617 .accept = sock_no_accept, 618 .getname = l2tp_ip_getname, 619 .poll = datagram_poll, 620 .ioctl = inet_ioctl, 621 .gettstamp = sock_gettstamp, 622 .listen = sock_no_listen, 623 .shutdown = inet_shutdown, 624 .setsockopt = sock_common_setsockopt, 625 .getsockopt = sock_common_getsockopt, 626 .sendmsg = inet_sendmsg, 627 .recvmsg = sock_common_recvmsg, 628 .mmap = sock_no_mmap, 629 .sendpage = sock_no_sendpage, 630 #ifdef CONFIG_COMPAT 631 .compat_setsockopt = compat_sock_common_setsockopt, 632 .compat_getsockopt = compat_sock_common_getsockopt, 633 #endif 634 }; 635 636 static struct inet_protosw l2tp_ip_protosw = { 637 .type = SOCK_DGRAM, 638 .protocol = IPPROTO_L2TP, 639 .prot = &l2tp_ip_prot, 640 .ops = &l2tp_ip_ops, 641 }; 642 643 static struct net_protocol l2tp_ip_protocol __read_mostly = { 644 .handler = l2tp_ip_recv, 645 .netns_ok = 1, 646 }; 647 648 static int __init l2tp_ip_init(void) 649 { 650 int err; 651 652 pr_info("L2TP IP encapsulation support (L2TPv3)\n"); 653 654 err = proto_register(&l2tp_ip_prot, 1); 655 if (err != 0) 656 goto out; 657 658 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 659 if (err) 660 goto out1; 661 662 inet_register_protosw(&l2tp_ip_protosw); 663 return 0; 664 665 out1: 666 proto_unregister(&l2tp_ip_prot); 667 out: 668 return err; 669 } 670 671 static void __exit l2tp_ip_exit(void) 672 { 673 inet_unregister_protosw(&l2tp_ip_protosw); 674 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 675 proto_unregister(&l2tp_ip_prot); 676 } 677 678 module_init(l2tp_ip_init); 679 module_exit(l2tp_ip_exit); 680 681 MODULE_LICENSE("GPL"); 682 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 683 MODULE_DESCRIPTION("L2TP over IP"); 684 MODULE_VERSION("1.0"); 685 686 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like 687 * enums 688 */ 689 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP); 690 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP); 691