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 net_eq(sock_net(sk), net) && 69 !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) && 70 !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)) 71 goto found; 72 } 73 74 sk = NULL; 75 found: 76 return sk; 77 } 78 79 static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id) 80 { 81 struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id); 82 if (sk) 83 sock_hold(sk); 84 85 return sk; 86 } 87 88 /* When processing receive frames, there are two cases to 89 * consider. Data frames consist of a non-zero session-id and an 90 * optional cookie. Control frames consist of a regular L2TP header 91 * preceded by 32-bits of zeros. 92 * 93 * L2TPv3 Session Header Over IP 94 * 95 * 0 1 2 3 96 * 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 97 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 98 * | Session ID | 99 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 100 * | Cookie (optional, maximum 64 bits)... 101 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 102 * | 103 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 104 * 105 * L2TPv3 Control Message Header Over IP 106 * 107 * 0 1 2 3 108 * 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 1 109 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 110 * | (32 bits of zeros) | 111 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 112 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length | 113 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 114 * | Control Connection ID | 115 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 116 * | Ns | Nr | 117 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 118 * 119 * All control frames are passed to userspace. 120 */ 121 static int l2tp_ip_recv(struct sk_buff *skb) 122 { 123 struct sock *sk; 124 u32 session_id; 125 u32 tunnel_id; 126 unsigned char *ptr, *optr; 127 struct l2tp_session *session; 128 struct l2tp_tunnel *tunnel = NULL; 129 int length; 130 int offset; 131 132 /* Point to L2TP header */ 133 optr = ptr = skb->data; 134 135 if (!pskb_may_pull(skb, 4)) 136 goto discard; 137 138 session_id = ntohl(*((__be32 *) ptr)); 139 ptr += 4; 140 141 /* RFC3931: L2TP/IP packets have the first 4 bytes containing 142 * the session_id. If it is 0, the packet is a L2TP control 143 * frame and the session_id value can be discarded. 144 */ 145 if (session_id == 0) { 146 __skb_pull(skb, 4); 147 goto pass_up; 148 } 149 150 /* Ok, this is a data packet. Lookup the session. */ 151 session = l2tp_session_find(&init_net, NULL, session_id); 152 if (session == NULL) 153 goto discard; 154 155 tunnel = session->tunnel; 156 if (tunnel == NULL) 157 goto discard; 158 159 /* Trace packet contents, if enabled */ 160 if (tunnel->debug & L2TP_MSG_DATA) { 161 length = min(32u, skb->len); 162 if (!pskb_may_pull(skb, length)) 163 goto discard; 164 165 printk(KERN_DEBUG "%s: ip recv: ", tunnel->name); 166 167 offset = 0; 168 do { 169 printk(" %02X", ptr[offset]); 170 } while (++offset < length); 171 172 printk("\n"); 173 } 174 175 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook); 176 177 return 0; 178 179 pass_up: 180 /* Get the tunnel_id from the L2TP header */ 181 if (!pskb_may_pull(skb, 12)) 182 goto discard; 183 184 if ((skb->data[0] & 0xc0) != 0xc0) 185 goto discard; 186 187 tunnel_id = ntohl(*(__be32 *) &skb->data[4]); 188 tunnel = l2tp_tunnel_find(&init_net, tunnel_id); 189 if (tunnel != NULL) 190 sk = tunnel->sock; 191 else { 192 struct iphdr *iph = (struct iphdr *) skb_network_header(skb); 193 194 read_lock_bh(&l2tp_ip_lock); 195 sk = __l2tp_ip_bind_lookup(&init_net, iph->daddr, 0, tunnel_id); 196 read_unlock_bh(&l2tp_ip_lock); 197 } 198 199 if (sk == NULL) 200 goto discard; 201 202 sock_hold(sk); 203 204 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 205 goto discard_put; 206 207 nf_reset(skb); 208 209 return sk_receive_skb(sk, skb, 1); 210 211 discard_put: 212 sock_put(sk); 213 214 discard: 215 kfree_skb(skb); 216 return 0; 217 } 218 219 static int l2tp_ip_open(struct sock *sk) 220 { 221 /* Prevent autobind. We don't have ports. */ 222 inet_sk(sk)->inet_num = IPPROTO_L2TP; 223 224 write_lock_bh(&l2tp_ip_lock); 225 sk_add_node(sk, &l2tp_ip_table); 226 write_unlock_bh(&l2tp_ip_lock); 227 228 return 0; 229 } 230 231 static void l2tp_ip_close(struct sock *sk, long timeout) 232 { 233 write_lock_bh(&l2tp_ip_lock); 234 hlist_del_init(&sk->sk_bind_node); 235 hlist_del_init(&sk->sk_node); 236 write_unlock_bh(&l2tp_ip_lock); 237 sk_common_release(sk); 238 } 239 240 static void l2tp_ip_destroy_sock(struct sock *sk) 241 { 242 struct sk_buff *skb; 243 244 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 245 kfree_skb(skb); 246 247 sk_refcnt_debug_dec(sk); 248 } 249 250 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 251 { 252 struct inet_sock *inet = inet_sk(sk); 253 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr; 254 int ret = -EINVAL; 255 int chk_addr_ret; 256 257 ret = -EADDRINUSE; 258 read_lock_bh(&l2tp_ip_lock); 259 if (__l2tp_ip_bind_lookup(&init_net, addr->l2tp_addr.s_addr, sk->sk_bound_dev_if, addr->l2tp_conn_id)) 260 goto out_in_use; 261 262 read_unlock_bh(&l2tp_ip_lock); 263 264 lock_sock(sk); 265 if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip)) 266 goto out; 267 268 chk_addr_ret = inet_addr_type(&init_net, addr->l2tp_addr.s_addr); 269 ret = -EADDRNOTAVAIL; 270 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL && 271 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST) 272 goto out; 273 274 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 sk_dst_reset(sk); 278 279 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id; 280 281 write_lock_bh(&l2tp_ip_lock); 282 sk_add_bind_node(sk, &l2tp_ip_bind_table); 283 sk_del_node_init(sk); 284 write_unlock_bh(&l2tp_ip_lock); 285 ret = 0; 286 out: 287 release_sock(sk); 288 289 return ret; 290 291 out_in_use: 292 read_unlock_bh(&l2tp_ip_lock); 293 294 return ret; 295 } 296 297 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 298 { 299 int rc; 300 struct inet_sock *inet = inet_sk(sk); 301 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr; 302 struct rtable *rt; 303 __be32 saddr; 304 int oif; 305 306 rc = -EINVAL; 307 if (addr_len < sizeof(*lsa)) 308 goto out; 309 310 rc = -EAFNOSUPPORT; 311 if (lsa->l2tp_family != AF_INET) 312 goto out; 313 314 sk_dst_reset(sk); 315 316 oif = sk->sk_bound_dev_if; 317 saddr = inet->inet_saddr; 318 319 rc = -EINVAL; 320 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr)) 321 goto out; 322 323 rt = ip_route_connect(lsa->l2tp_addr.s_addr, saddr, 324 RT_CONN_FLAGS(sk), oif, 325 IPPROTO_L2TP, 326 0, 0, sk, true); 327 if (IS_ERR(rt)) { 328 rc = PTR_ERR(rt); 329 if (rc == -ENETUNREACH) 330 IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES); 331 goto out; 332 } 333 334 rc = -ENETUNREACH; 335 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { 336 ip_rt_put(rt); 337 goto out; 338 } 339 340 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 341 342 if (!inet->inet_saddr) 343 inet->inet_saddr = rt->rt_src; 344 if (!inet->inet_rcv_saddr) 345 inet->inet_rcv_saddr = rt->rt_src; 346 inet->inet_daddr = rt->rt_dst; 347 sk->sk_state = TCP_ESTABLISHED; 348 inet->inet_id = jiffies; 349 350 sk_dst_set(sk, &rt->dst); 351 352 write_lock_bh(&l2tp_ip_lock); 353 hlist_del_init(&sk->sk_bind_node); 354 sk_add_bind_node(sk, &l2tp_ip_bind_table); 355 write_unlock_bh(&l2tp_ip_lock); 356 357 rc = 0; 358 out: 359 return rc; 360 } 361 362 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr, 363 int *uaddr_len, int peer) 364 { 365 struct sock *sk = sock->sk; 366 struct inet_sock *inet = inet_sk(sk); 367 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk); 368 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr; 369 370 memset(lsa, 0, sizeof(*lsa)); 371 lsa->l2tp_family = AF_INET; 372 if (peer) { 373 if (!inet->inet_dport) 374 return -ENOTCONN; 375 lsa->l2tp_conn_id = lsk->peer_conn_id; 376 lsa->l2tp_addr.s_addr = inet->inet_daddr; 377 } else { 378 __be32 addr = inet->inet_rcv_saddr; 379 if (!addr) 380 addr = inet->inet_saddr; 381 lsa->l2tp_conn_id = lsk->conn_id; 382 lsa->l2tp_addr.s_addr = addr; 383 } 384 *uaddr_len = sizeof(*lsa); 385 return 0; 386 } 387 388 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb) 389 { 390 int rc; 391 392 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 393 goto drop; 394 395 nf_reset(skb); 396 397 /* Charge it to the socket, dropping if the queue is full. */ 398 rc = sock_queue_rcv_skb(sk, skb); 399 if (rc < 0) 400 goto drop; 401 402 return 0; 403 404 drop: 405 IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS); 406 kfree_skb(skb); 407 return -1; 408 } 409 410 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 411 * control frames. 412 */ 413 static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len) 414 { 415 struct sk_buff *skb; 416 int rc; 417 struct l2tp_ip_sock *lsa = l2tp_ip_sk(sk); 418 struct inet_sock *inet = inet_sk(sk); 419 struct ip_options *opt = inet->opt; 420 struct rtable *rt = NULL; 421 int connected = 0; 422 __be32 daddr; 423 424 if (sock_flag(sk, SOCK_DEAD)) 425 return -ENOTCONN; 426 427 /* Get and verify the address. */ 428 if (msg->msg_name) { 429 struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name; 430 if (msg->msg_namelen < sizeof(*lip)) 431 return -EINVAL; 432 433 if (lip->l2tp_family != AF_INET) { 434 if (lip->l2tp_family != AF_UNSPEC) 435 return -EAFNOSUPPORT; 436 } 437 438 daddr = lip->l2tp_addr.s_addr; 439 } else { 440 if (sk->sk_state != TCP_ESTABLISHED) 441 return -EDESTADDRREQ; 442 443 daddr = inet->inet_daddr; 444 connected = 1; 445 } 446 447 /* Allocate a socket buffer */ 448 rc = -ENOMEM; 449 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) + 450 4 + len, 0, GFP_KERNEL); 451 if (!skb) 452 goto error; 453 454 /* Reserve space for headers, putting IP header on 4-byte boundary. */ 455 skb_reserve(skb, 2 + NET_SKB_PAD); 456 skb_reset_network_header(skb); 457 skb_reserve(skb, sizeof(struct iphdr)); 458 skb_reset_transport_header(skb); 459 460 /* Insert 0 session_id */ 461 *((__be32 *) skb_put(skb, 4)) = 0; 462 463 /* Copy user data into skb */ 464 rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len); 465 if (rc < 0) { 466 kfree_skb(skb); 467 goto error; 468 } 469 470 if (connected) 471 rt = (struct rtable *) __sk_dst_check(sk, 0); 472 473 if (rt == NULL) { 474 /* Use correct destination address if we have options. */ 475 if (opt && opt->srr) 476 daddr = opt->faddr; 477 478 /* If this fails, retransmit mechanism of transport layer will 479 * keep trying until route appears or the connection times 480 * itself out. 481 */ 482 rt = ip_route_output_ports(sock_net(sk), sk, 483 daddr, inet->inet_saddr, 484 inet->inet_dport, inet->inet_sport, 485 sk->sk_protocol, RT_CONN_FLAGS(sk), 486 sk->sk_bound_dev_if); 487 if (IS_ERR(rt)) 488 goto no_route; 489 sk_setup_caps(sk, &rt->dst); 490 } 491 skb_dst_set(skb, dst_clone(&rt->dst)); 492 493 /* Queue the packet to IP for output */ 494 rc = ip_queue_xmit(skb); 495 496 error: 497 /* Update stats */ 498 if (rc >= 0) { 499 lsa->tx_packets++; 500 lsa->tx_bytes += len; 501 rc = len; 502 } else { 503 lsa->tx_errors++; 504 } 505 506 return rc; 507 508 no_route: 509 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 510 kfree_skb(skb); 511 return -EHOSTUNREACH; 512 } 513 514 static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 515 size_t len, int noblock, int flags, int *addr_len) 516 { 517 struct inet_sock *inet = inet_sk(sk); 518 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk); 519 size_t copied = 0; 520 int err = -EOPNOTSUPP; 521 struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name; 522 struct sk_buff *skb; 523 524 if (flags & MSG_OOB) 525 goto out; 526 527 if (addr_len) 528 *addr_len = sizeof(*sin); 529 530 skb = skb_recv_datagram(sk, flags, noblock, &err); 531 if (!skb) 532 goto out; 533 534 copied = skb->len; 535 if (len < copied) { 536 msg->msg_flags |= MSG_TRUNC; 537 copied = len; 538 } 539 540 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied); 541 if (err) 542 goto done; 543 544 sock_recv_timestamp(msg, sk, skb); 545 546 /* Copy the address. */ 547 if (sin) { 548 sin->sin_family = AF_INET; 549 sin->sin_addr.s_addr = ip_hdr(skb)->saddr; 550 sin->sin_port = 0; 551 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero)); 552 } 553 if (inet->cmsg_flags) 554 ip_cmsg_recv(msg, skb); 555 if (flags & MSG_TRUNC) 556 copied = skb->len; 557 done: 558 skb_free_datagram(sk, skb); 559 out: 560 if (err) { 561 lsk->rx_errors++; 562 return err; 563 } 564 565 lsk->rx_packets++; 566 lsk->rx_bytes += copied; 567 568 return copied; 569 } 570 571 static struct proto l2tp_ip_prot = { 572 .name = "L2TP/IP", 573 .owner = THIS_MODULE, 574 .init = l2tp_ip_open, 575 .close = l2tp_ip_close, 576 .bind = l2tp_ip_bind, 577 .connect = l2tp_ip_connect, 578 .disconnect = udp_disconnect, 579 .ioctl = udp_ioctl, 580 .destroy = l2tp_ip_destroy_sock, 581 .setsockopt = ip_setsockopt, 582 .getsockopt = ip_getsockopt, 583 .sendmsg = l2tp_ip_sendmsg, 584 .recvmsg = l2tp_ip_recvmsg, 585 .backlog_rcv = l2tp_ip_backlog_recv, 586 .hash = inet_hash, 587 .unhash = inet_unhash, 588 .obj_size = sizeof(struct l2tp_ip_sock), 589 #ifdef CONFIG_COMPAT 590 .compat_setsockopt = compat_ip_setsockopt, 591 .compat_getsockopt = compat_ip_getsockopt, 592 #endif 593 }; 594 595 static const struct proto_ops l2tp_ip_ops = { 596 .family = PF_INET, 597 .owner = THIS_MODULE, 598 .release = inet_release, 599 .bind = inet_bind, 600 .connect = inet_dgram_connect, 601 .socketpair = sock_no_socketpair, 602 .accept = sock_no_accept, 603 .getname = l2tp_ip_getname, 604 .poll = datagram_poll, 605 .ioctl = inet_ioctl, 606 .listen = sock_no_listen, 607 .shutdown = inet_shutdown, 608 .setsockopt = sock_common_setsockopt, 609 .getsockopt = sock_common_getsockopt, 610 .sendmsg = inet_sendmsg, 611 .recvmsg = sock_common_recvmsg, 612 .mmap = sock_no_mmap, 613 .sendpage = sock_no_sendpage, 614 #ifdef CONFIG_COMPAT 615 .compat_setsockopt = compat_sock_common_setsockopt, 616 .compat_getsockopt = compat_sock_common_getsockopt, 617 #endif 618 }; 619 620 static struct inet_protosw l2tp_ip_protosw = { 621 .type = SOCK_DGRAM, 622 .protocol = IPPROTO_L2TP, 623 .prot = &l2tp_ip_prot, 624 .ops = &l2tp_ip_ops, 625 .no_check = 0, 626 }; 627 628 static struct net_protocol l2tp_ip_protocol __read_mostly = { 629 .handler = l2tp_ip_recv, 630 }; 631 632 static int __init l2tp_ip_init(void) 633 { 634 int err; 635 636 printk(KERN_INFO "L2TP IP encapsulation support (L2TPv3)\n"); 637 638 err = proto_register(&l2tp_ip_prot, 1); 639 if (err != 0) 640 goto out; 641 642 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 643 if (err) 644 goto out1; 645 646 inet_register_protosw(&l2tp_ip_protosw); 647 return 0; 648 649 out1: 650 proto_unregister(&l2tp_ip_prot); 651 out: 652 return err; 653 } 654 655 static void __exit l2tp_ip_exit(void) 656 { 657 inet_unregister_protosw(&l2tp_ip_protosw); 658 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP); 659 proto_unregister(&l2tp_ip_prot); 660 } 661 662 module_init(l2tp_ip_init); 663 module_exit(l2tp_ip_exit); 664 665 MODULE_LICENSE("GPL"); 666 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 667 MODULE_DESCRIPTION("L2TP over IP"); 668 MODULE_VERSION("1.0"); 669 670 /* Use the value of SOCK_DGRAM (2) directory, because __stringify does't like 671 * enums 672 */ 673 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP); 674