1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * L2TPv3 IP encapsulation support 4 * 5 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <asm/ioctls.h> 11 #include <linux/icmp.h> 12 #include <linux/module.h> 13 #include <linux/skbuff.h> 14 #include <linux/random.h> 15 #include <linux/socket.h> 16 #include <linux/l2tp.h> 17 #include <linux/in.h> 18 #include <net/sock.h> 19 #include <net/ip.h> 20 #include <net/icmp.h> 21 #include <net/udp.h> 22 #include <net/inet_common.h> 23 #include <net/inet_hashtables.h> 24 #include <net/tcp_states.h> 25 #include <net/protocol.h> 26 #include <net/xfrm.h> 27 28 #include "l2tp_core.h" 29 30 struct l2tp_ip_sock { 31 /* inet_sock has to be the first member of l2tp_ip_sock */ 32 struct inet_sock inet; 33 34 u32 conn_id; 35 u32 peer_conn_id; 36 }; 37 38 static DEFINE_RWLOCK(l2tp_ip_lock); 39 static struct hlist_head l2tp_ip_table; 40 static struct hlist_head l2tp_ip_bind_table; 41 42 static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk) 43 { 44 return (struct l2tp_ip_sock *)sk; 45 } 46 47 static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr, 48 __be32 raddr, int dif, u32 tunnel_id) 49 { 50 struct sock *sk; 51 52 sk_for_each_bound(sk, &l2tp_ip_bind_table) { 53 const struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk); 54 const struct inet_sock *inet = inet_sk(sk); 55 56 if (!net_eq(sock_net(sk), net)) 57 continue; 58 59 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif) 60 continue; 61 62 if (inet->inet_rcv_saddr && laddr && 63 inet->inet_rcv_saddr != laddr) 64 continue; 65 66 if (inet->inet_daddr && raddr && inet->inet_daddr != raddr) 67 continue; 68 69 if (l2tp->conn_id != tunnel_id) 70 continue; 71 72 goto found; 73 } 74 75 sk = NULL; 76 found: 77 return sk; 78 } 79 80 /* When processing receive frames, there are two cases to 81 * consider. Data frames consist of a non-zero session-id and an 82 * optional cookie. Control frames consist of a regular L2TP header 83 * preceded by 32-bits of zeros. 84 * 85 * L2TPv3 Session Header Over IP 86 * 87 * 0 1 2 3 88 * 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 89 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 90 * | Session ID | 91 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 92 * | Cookie (optional, maximum 64 bits)... 93 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 94 * | 95 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 96 * 97 * L2TPv3 Control Message Header Over IP 98 * 99 * 0 1 2 3 100 * 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 1 101 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 102 * | (32 bits of zeros) | 103 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 104 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length | 105 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 106 * | Control Connection ID | 107 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 108 * | Ns | Nr | 109 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 110 * 111 * All control frames are passed to userspace. 112 */ 113 static int l2tp_ip_recv(struct sk_buff *skb) 114 { 115 struct net *net = dev_net(skb->dev); 116 struct sock *sk; 117 u32 session_id; 118 u32 tunnel_id; 119 unsigned char *ptr, *optr; 120 struct l2tp_session *session; 121 struct l2tp_tunnel *tunnel = NULL; 122 struct iphdr *iph; 123 int length; 124 125 if (!pskb_may_pull(skb, 4)) 126 goto discard; 127 128 /* Point to L2TP header */ 129 optr = ptr = skb->data; 130 session_id = ntohl(*((__be32 *) ptr)); 131 ptr += 4; 132 133 /* RFC3931: L2TP/IP packets have the first 4 bytes containing 134 * the session_id. If it is 0, the packet is a L2TP control 135 * frame and the session_id value can be discarded. 136 */ 137 if (session_id == 0) { 138 __skb_pull(skb, 4); 139 goto pass_up; 140 } 141 142 /* Ok, this is a data packet. Lookup the session. */ 143 session = l2tp_session_get(net, session_id); 144 if (!session) 145 goto discard; 146 147 tunnel = session->tunnel; 148 if (!tunnel) 149 goto discard_sess; 150 151 /* Trace packet contents, if enabled */ 152 if (tunnel->debug & L2TP_MSG_DATA) { 153 length = min(32u, skb->len); 154 if (!pskb_may_pull(skb, length)) 155 goto discard_sess; 156 157 /* Point to L2TP header */ 158 optr = 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_open(struct sock *sk) 213 { 214 /* Prevent autobind. We don't have ports. */ 215 inet_sk(sk)->inet_num = IPPROTO_L2TP; 216 217 write_lock_bh(&l2tp_ip_lock); 218 sk_add_node(sk, &l2tp_ip_table); 219 write_unlock_bh(&l2tp_ip_lock); 220 221 return 0; 222 } 223 224 static void l2tp_ip_close(struct sock *sk, long timeout) 225 { 226 write_lock_bh(&l2tp_ip_lock); 227 hlist_del_init(&sk->sk_bind_node); 228 sk_del_node_init(sk); 229 write_unlock_bh(&l2tp_ip_lock); 230 sk_common_release(sk); 231 } 232 233 static void l2tp_ip_destroy_sock(struct sock *sk) 234 { 235 struct sk_buff *skb; 236 struct l2tp_tunnel *tunnel = sk->sk_user_data; 237 238 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 239 kfree_skb(skb); 240 241 if (tunnel) 242 l2tp_tunnel_delete(tunnel); 243 } 244 245 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 246 { 247 struct inet_sock *inet = inet_sk(sk); 248 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr; 249 struct net *net = sock_net(sk); 250 int ret; 251 int chk_addr_ret; 252 253 if (addr_len < sizeof(struct sockaddr_l2tpip)) 254 return -EINVAL; 255 if (addr->l2tp_family != AF_INET) 256 return -EINVAL; 257 258 lock_sock(sk); 259 260 ret = -EINVAL; 261 if (!sock_flag(sk, SOCK_ZAPPED)) 262 goto out; 263 264 if (sk->sk_state != TCP_CLOSE) 265 goto out; 266 267 chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr); 268 ret = -EADDRNOTAVAIL; 269 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL && 270 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST) 271 goto out; 272 273 if (addr->l2tp_addr.s_addr) 274 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr; 275 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST) 276 inet->inet_saddr = 0; /* Use device */ 277 278 write_lock_bh(&l2tp_ip_lock); 279 if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0, 280 sk->sk_bound_dev_if, addr->l2tp_conn_id)) { 281 write_unlock_bh(&l2tp_ip_lock); 282 ret = -EADDRINUSE; 283 goto out; 284 } 285 286 sk_dst_reset(sk); 287 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id; 288 289 sk_add_bind_node(sk, &l2tp_ip_bind_table); 290 sk_del_node_init(sk); 291 write_unlock_bh(&l2tp_ip_lock); 292 293 ret = 0; 294 sock_reset_flag(sk, SOCK_ZAPPED); 295 296 out: 297 release_sock(sk); 298 299 return ret; 300 } 301 302 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 303 { 304 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr; 305 int rc; 306 307 if (addr_len < sizeof(*lsa)) 308 return -EINVAL; 309 310 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr)) 311 return -EINVAL; 312 313 lock_sock(sk); 314 315 /* Must bind first - autobinding does not work */ 316 if (sock_flag(sk, SOCK_ZAPPED)) { 317 rc = -EINVAL; 318 goto out_sk; 319 } 320 321 rc = __ip4_datagram_connect(sk, uaddr, addr_len); 322 if (rc < 0) 323 goto out_sk; 324 325 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 326 327 write_lock_bh(&l2tp_ip_lock); 328 hlist_del_init(&sk->sk_bind_node); 329 sk_add_bind_node(sk, &l2tp_ip_bind_table); 330 write_unlock_bh(&l2tp_ip_lock); 331 332 out_sk: 333 release_sock(sk); 334 335 return rc; 336 } 337 338 static int l2tp_ip_disconnect(struct sock *sk, int flags) 339 { 340 if (sock_flag(sk, SOCK_ZAPPED)) 341 return 0; 342 343 return __udp_disconnect(sk, flags); 344 } 345 346 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr, 347 int peer) 348 { 349 struct sock *sk = sock->sk; 350 struct inet_sock *inet = inet_sk(sk); 351 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk); 352 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr; 353 354 memset(lsa, 0, sizeof(*lsa)); 355 lsa->l2tp_family = AF_INET; 356 if (peer) { 357 if (!inet->inet_dport) 358 return -ENOTCONN; 359 lsa->l2tp_conn_id = lsk->peer_conn_id; 360 lsa->l2tp_addr.s_addr = inet->inet_daddr; 361 } else { 362 __be32 addr = inet->inet_rcv_saddr; 363 if (!addr) 364 addr = inet->inet_saddr; 365 lsa->l2tp_conn_id = lsk->conn_id; 366 lsa->l2tp_addr.s_addr = addr; 367 } 368 return sizeof(*lsa); 369 } 370 371 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb) 372 { 373 int rc; 374 375 /* Charge it to the socket, dropping if the queue is full. */ 376 rc = sock_queue_rcv_skb(sk, skb); 377 if (rc < 0) 378 goto drop; 379 380 return 0; 381 382 drop: 383 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); 384 kfree_skb(skb); 385 return 0; 386 } 387 388 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 389 * control frames. 390 */ 391 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 392 { 393 struct sk_buff *skb; 394 int rc; 395 struct inet_sock *inet = inet_sk(sk); 396 struct rtable *rt = NULL; 397 struct flowi4 *fl4; 398 int connected = 0; 399 __be32 daddr; 400 401 lock_sock(sk); 402 403 rc = -ENOTCONN; 404 if (sock_flag(sk, SOCK_DEAD)) 405 goto out; 406 407 /* Get and verify the address. */ 408 if (msg->msg_name) { 409 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name); 410 rc = -EINVAL; 411 if (msg->msg_namelen < sizeof(*lip)) 412 goto out; 413 414 if (lip->l2tp_family != AF_INET) { 415 rc = -EAFNOSUPPORT; 416 if (lip->l2tp_family != AF_UNSPEC) 417 goto out; 418 } 419 420 daddr = lip->l2tp_addr.s_addr; 421 } else { 422 rc = -EDESTADDRREQ; 423 if (sk->sk_state != TCP_ESTABLISHED) 424 goto out; 425 426 daddr = inet->inet_daddr; 427 connected = 1; 428 } 429 430 /* Allocate a socket buffer */ 431 rc = -ENOMEM; 432 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) + 433 4 + len, 0, GFP_KERNEL); 434 if (!skb) 435 goto error; 436 437 /* Reserve space for headers, putting IP header on 4-byte boundary. */ 438 skb_reserve(skb, 2 + NET_SKB_PAD); 439 skb_reset_network_header(skb); 440 skb_reserve(skb, sizeof(struct iphdr)); 441 skb_reset_transport_header(skb); 442 443 /* Insert 0 session_id */ 444 *((__be32 *) skb_put(skb, 4)) = 0; 445 446 /* Copy user data into skb */ 447 rc = memcpy_from_msg(skb_put(skb, len), msg, len); 448 if (rc < 0) { 449 kfree_skb(skb); 450 goto error; 451 } 452 453 fl4 = &inet->cork.fl.u.ip4; 454 if (connected) 455 rt = (struct rtable *) __sk_dst_check(sk, 0); 456 457 rcu_read_lock(); 458 if (rt == NULL) { 459 const struct ip_options_rcu *inet_opt; 460 461 inet_opt = rcu_dereference(inet->inet_opt); 462 463 /* Use correct destination address if we have options. */ 464 if (inet_opt && inet_opt->opt.srr) 465 daddr = inet_opt->opt.faddr; 466 467 /* If this fails, retransmit mechanism of transport layer will 468 * keep trying until route appears or the connection times 469 * itself out. 470 */ 471 rt = ip_route_output_ports(sock_net(sk), fl4, sk, 472 daddr, inet->inet_saddr, 473 inet->inet_dport, inet->inet_sport, 474 sk->sk_protocol, RT_CONN_FLAGS(sk), 475 sk->sk_bound_dev_if); 476 if (IS_ERR(rt)) 477 goto no_route; 478 if (connected) { 479 sk_setup_caps(sk, &rt->dst); 480 } else { 481 skb_dst_set(skb, &rt->dst); 482 goto xmit; 483 } 484 } 485 486 /* We dont need to clone dst here, it is guaranteed to not disappear. 487 * __dev_xmit_skb() might force a refcount if needed. 488 */ 489 skb_dst_set_noref(skb, &rt->dst); 490 491 xmit: 492 /* Queue the packet to IP for output */ 493 rc = ip_queue_xmit(sk, skb, &inet->cork.fl); 494 rcu_read_unlock(); 495 496 error: 497 if (rc >= 0) 498 rc = len; 499 500 out: 501 release_sock(sk); 502 return rc; 503 504 no_route: 505 rcu_read_unlock(); 506 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 507 kfree_skb(skb); 508 rc = -EHOSTUNREACH; 509 goto out; 510 } 511 512 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg, 513 size_t len, int noblock, int flags, int *addr_len) 514 { 515 struct inet_sock *inet = inet_sk(sk); 516 size_t copied = 0; 517 int err = -EOPNOTSUPP; 518 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name); 519 struct sk_buff *skb; 520 521 if (flags & MSG_OOB) 522 goto out; 523 524 skb = skb_recv_datagram(sk, flags, noblock, &err); 525 if (!skb) 526 goto out; 527 528 copied = skb->len; 529 if (len < copied) { 530 msg->msg_flags |= MSG_TRUNC; 531 copied = len; 532 } 533 534 err = skb_copy_datagram_msg(skb, 0, msg, copied); 535 if (err) 536 goto done; 537 538 sock_recv_timestamp(msg, sk, skb); 539 540 /* Copy the address. */ 541 if (sin) { 542 sin->sin_family = AF_INET; 543 sin->sin_addr.s_addr = ip_hdr(skb)->saddr; 544 sin->sin_port = 0; 545 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero)); 546 *addr_len = sizeof(*sin); 547 } 548 if (inet->cmsg_flags) 549 ip_cmsg_recv(msg, skb); 550 if (flags & MSG_TRUNC) 551 copied = skb->len; 552 done: 553 skb_free_datagram(sk, skb); 554 out: 555 return err ? err : copied; 556 } 557 558 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg) 559 { 560 struct sk_buff *skb; 561 int amount; 562 563 switch (cmd) { 564 case SIOCOUTQ: 565 amount = sk_wmem_alloc_get(sk); 566 break; 567 case SIOCINQ: 568 spin_lock_bh(&sk->sk_receive_queue.lock); 569 skb = skb_peek(&sk->sk_receive_queue); 570 amount = skb ? skb->len : 0; 571 spin_unlock_bh(&sk->sk_receive_queue.lock); 572 break; 573 574 default: 575 return -ENOIOCTLCMD; 576 } 577 578 return put_user(amount, (int __user *)arg); 579 } 580 EXPORT_SYMBOL(l2tp_ioctl); 581 582 static struct proto l2tp_ip_prot = { 583 .name = "L2TP/IP", 584 .owner = THIS_MODULE, 585 .init = l2tp_ip_open, 586 .close = l2tp_ip_close, 587 .bind = l2tp_ip_bind, 588 .connect = l2tp_ip_connect, 589 .disconnect = l2tp_ip_disconnect, 590 .ioctl = l2tp_ioctl, 591 .destroy = l2tp_ip_destroy_sock, 592 .setsockopt = ip_setsockopt, 593 .getsockopt = ip_getsockopt, 594 .sendmsg = l2tp_ip_sendmsg, 595 .recvmsg = l2tp_ip_recvmsg, 596 .backlog_rcv = l2tp_ip_backlog_recv, 597 .hash = inet_hash, 598 .unhash = inet_unhash, 599 .obj_size = sizeof(struct l2tp_ip_sock), 600 #ifdef CONFIG_COMPAT 601 .compat_setsockopt = compat_ip_setsockopt, 602 .compat_getsockopt = compat_ip_getsockopt, 603 #endif 604 }; 605 606 static const struct proto_ops l2tp_ip_ops = { 607 .family = PF_INET, 608 .owner = THIS_MODULE, 609 .release = inet_release, 610 .bind = inet_bind, 611 .connect = inet_dgram_connect, 612 .socketpair = sock_no_socketpair, 613 .accept = sock_no_accept, 614 .getname = l2tp_ip_getname, 615 .poll = datagram_poll, 616 .ioctl = inet_ioctl, 617 .gettstamp = sock_gettstamp, 618 .listen = sock_no_listen, 619 .shutdown = inet_shutdown, 620 .setsockopt = sock_common_setsockopt, 621 .getsockopt = sock_common_getsockopt, 622 .sendmsg = inet_sendmsg, 623 .recvmsg = sock_common_recvmsg, 624 .mmap = sock_no_mmap, 625 .sendpage = sock_no_sendpage, 626 #ifdef CONFIG_COMPAT 627 .compat_setsockopt = compat_sock_common_setsockopt, 628 .compat_getsockopt = compat_sock_common_getsockopt, 629 #endif 630 }; 631 632 static struct inet_protosw l2tp_ip_protosw = { 633 .type = SOCK_DGRAM, 634 .protocol = IPPROTO_L2TP, 635 .prot = &l2tp_ip_prot, 636 .ops = &l2tp_ip_ops, 637 }; 638 639 static struct net_protocol l2tp_ip_protocol __read_mostly = { 640 .handler = l2tp_ip_recv, 641 .netns_ok = 1, 642 }; 643 644 static int __init l2tp_ip_init(void) 645 { 646 int err; 647 648 pr_info("L2TP IP encapsulation support (L2TPv3)\n"); 649 650 err = proto_register(&l2tp_ip_prot, 1); 651 if (err != 0) 652 goto out; 653 654 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 655 if (err) 656 goto out1; 657 658 inet_register_protosw(&l2tp_ip_protosw); 659 return 0; 660 661 out1: 662 proto_unregister(&l2tp_ip_prot); 663 out: 664 return err; 665 } 666 667 static void __exit l2tp_ip_exit(void) 668 { 669 inet_unregister_protosw(&l2tp_ip_protosw); 670 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 671 proto_unregister(&l2tp_ip_prot); 672 } 673 674 module_init(l2tp_ip_init); 675 module_exit(l2tp_ip_exit); 676 677 MODULE_LICENSE("GPL"); 678 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 679 MODULE_DESCRIPTION("L2TP over IP"); 680 MODULE_VERSION("1.0"); 681 682 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like 683 * enums 684 */ 685 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP); 686 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP); 687