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 int bound_dev_if; 54 55 if (!net_eq(sock_net(sk), net)) 56 continue; 57 58 bound_dev_if = READ_ONCE(sk->sk_bound_dev_if); 59 if (bound_dev_if && dif && 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; 123 124 if (!pskb_may_pull(skb, 4)) 125 goto discard; 126 127 /* Point to L2TP header */ 128 optr = skb->data; 129 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 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) 152 goto discard_sess; 153 154 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len); 155 l2tp_session_dec_refcount(session); 156 157 return 0; 158 159 pass_up: 160 /* Get the tunnel_id from the L2TP header */ 161 if (!pskb_may_pull(skb, 12)) 162 goto discard; 163 164 if ((skb->data[0] & 0xc0) != 0xc0) 165 goto discard; 166 167 tunnel_id = ntohl(*(__be32 *)&skb->data[4]); 168 iph = (struct iphdr *)skb_network_header(skb); 169 170 read_lock_bh(&l2tp_ip_lock); 171 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb), 172 tunnel_id); 173 if (!sk) { 174 read_unlock_bh(&l2tp_ip_lock); 175 goto discard; 176 } 177 sock_hold(sk); 178 read_unlock_bh(&l2tp_ip_lock); 179 180 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 181 goto discard_put; 182 183 nf_reset_ct(skb); 184 185 return sk_receive_skb(sk, skb, 1); 186 187 discard_sess: 188 l2tp_session_dec_refcount(session); 189 goto discard; 190 191 discard_put: 192 sock_put(sk); 193 194 discard: 195 kfree_skb(skb); 196 return 0; 197 } 198 199 static int l2tp_ip_hash(struct sock *sk) 200 { 201 if (sk_unhashed(sk)) { 202 write_lock_bh(&l2tp_ip_lock); 203 sk_add_node(sk, &l2tp_ip_table); 204 write_unlock_bh(&l2tp_ip_lock); 205 } 206 return 0; 207 } 208 209 static void l2tp_ip_unhash(struct sock *sk) 210 { 211 if (sk_unhashed(sk)) 212 return; 213 write_lock_bh(&l2tp_ip_lock); 214 sk_del_node_init(sk); 215 write_unlock_bh(&l2tp_ip_lock); 216 } 217 218 static int l2tp_ip_open(struct sock *sk) 219 { 220 /* Prevent autobind. We don't have ports. */ 221 inet_sk(sk)->inet_num = IPPROTO_L2TP; 222 223 l2tp_ip_hash(sk); 224 return 0; 225 } 226 227 static void l2tp_ip_close(struct sock *sk, long timeout) 228 { 229 write_lock_bh(&l2tp_ip_lock); 230 hlist_del_init(&sk->sk_bind_node); 231 sk_del_node_init(sk); 232 write_unlock_bh(&l2tp_ip_lock); 233 sk_common_release(sk); 234 } 235 236 static void l2tp_ip_destroy_sock(struct sock *sk) 237 { 238 struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk); 239 struct sk_buff *skb; 240 241 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) 242 kfree_skb(skb); 243 244 if (tunnel) 245 l2tp_tunnel_delete(tunnel); 246 } 247 248 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 249 { 250 struct inet_sock *inet = inet_sk(sk); 251 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *)uaddr; 252 struct net *net = sock_net(sk); 253 int ret; 254 int chk_addr_ret; 255 256 if (addr_len < sizeof(struct sockaddr_l2tpip)) 257 return -EINVAL; 258 if (addr->l2tp_family != AF_INET) 259 return -EINVAL; 260 261 lock_sock(sk); 262 263 ret = -EINVAL; 264 if (!sock_flag(sk, SOCK_ZAPPED)) 265 goto out; 266 267 if (sk->sk_state != TCP_CLOSE) 268 goto out; 269 270 chk_addr_ret = inet_addr_type(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 if (addr->l2tp_addr.s_addr) { 277 inet->inet_rcv_saddr = addr->l2tp_addr.s_addr; 278 inet->inet_saddr = addr->l2tp_addr.s_addr; 279 } 280 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST) 281 inet->inet_saddr = 0; /* Use device */ 282 283 write_lock_bh(&l2tp_ip_lock); 284 if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0, 285 sk->sk_bound_dev_if, addr->l2tp_conn_id)) { 286 write_unlock_bh(&l2tp_ip_lock); 287 ret = -EADDRINUSE; 288 goto out; 289 } 290 291 sk_dst_reset(sk); 292 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id; 293 294 sk_add_bind_node(sk, &l2tp_ip_bind_table); 295 sk_del_node_init(sk); 296 write_unlock_bh(&l2tp_ip_lock); 297 298 ret = 0; 299 sock_reset_flag(sk, SOCK_ZAPPED); 300 301 out: 302 release_sock(sk); 303 304 return ret; 305 } 306 307 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 308 { 309 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr; 310 int rc; 311 312 if (addr_len < sizeof(*lsa)) 313 return -EINVAL; 314 315 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr)) 316 return -EINVAL; 317 318 lock_sock(sk); 319 320 /* Must bind first - autobinding does not work */ 321 if (sock_flag(sk, SOCK_ZAPPED)) { 322 rc = -EINVAL; 323 goto out_sk; 324 } 325 326 rc = __ip4_datagram_connect(sk, uaddr, addr_len); 327 if (rc < 0) 328 goto out_sk; 329 330 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 331 332 write_lock_bh(&l2tp_ip_lock); 333 hlist_del_init(&sk->sk_bind_node); 334 sk_add_bind_node(sk, &l2tp_ip_bind_table); 335 write_unlock_bh(&l2tp_ip_lock); 336 337 out_sk: 338 release_sock(sk); 339 340 return rc; 341 } 342 343 static int l2tp_ip_disconnect(struct sock *sk, int flags) 344 { 345 if (sock_flag(sk, SOCK_ZAPPED)) 346 return 0; 347 348 return __udp_disconnect(sk, flags); 349 } 350 351 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr, 352 int peer) 353 { 354 struct sock *sk = sock->sk; 355 struct inet_sock *inet = inet_sk(sk); 356 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk); 357 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr; 358 359 memset(lsa, 0, sizeof(*lsa)); 360 lsa->l2tp_family = AF_INET; 361 if (peer) { 362 if (!inet->inet_dport) 363 return -ENOTCONN; 364 lsa->l2tp_conn_id = lsk->peer_conn_id; 365 lsa->l2tp_addr.s_addr = inet->inet_daddr; 366 } else { 367 __be32 addr = inet->inet_rcv_saddr; 368 369 if (!addr) 370 addr = inet->inet_saddr; 371 lsa->l2tp_conn_id = lsk->conn_id; 372 lsa->l2tp_addr.s_addr = addr; 373 } 374 return sizeof(*lsa); 375 } 376 377 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb) 378 { 379 int rc; 380 381 /* Charge it to the socket, dropping if the queue is full. */ 382 rc = sock_queue_rcv_skb(sk, skb); 383 if (rc < 0) 384 goto drop; 385 386 return 0; 387 388 drop: 389 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); 390 kfree_skb(skb); 391 return 0; 392 } 393 394 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 395 * control frames. 396 */ 397 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 398 { 399 struct sk_buff *skb; 400 int rc; 401 struct inet_sock *inet = inet_sk(sk); 402 struct rtable *rt = NULL; 403 struct flowi4 *fl4; 404 int connected = 0; 405 __be32 daddr; 406 407 lock_sock(sk); 408 409 rc = -ENOTCONN; 410 if (sock_flag(sk, SOCK_DEAD)) 411 goto out; 412 413 /* Get and verify the address. */ 414 if (msg->msg_name) { 415 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name); 416 417 rc = -EINVAL; 418 if (msg->msg_namelen < sizeof(*lip)) 419 goto out; 420 421 if (lip->l2tp_family != AF_INET) { 422 rc = -EAFNOSUPPORT; 423 if (lip->l2tp_family != AF_UNSPEC) 424 goto out; 425 } 426 427 daddr = lip->l2tp_addr.s_addr; 428 } else { 429 rc = -EDESTADDRREQ; 430 if (sk->sk_state != TCP_ESTABLISHED) 431 goto out; 432 433 daddr = inet->inet_daddr; 434 connected = 1; 435 } 436 437 /* Allocate a socket buffer */ 438 rc = -ENOMEM; 439 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) + 440 4 + len, 0, GFP_KERNEL); 441 if (!skb) 442 goto error; 443 444 /* Reserve space for headers, putting IP header on 4-byte boundary. */ 445 skb_reserve(skb, 2 + NET_SKB_PAD); 446 skb_reset_network_header(skb); 447 skb_reserve(skb, sizeof(struct iphdr)); 448 skb_reset_transport_header(skb); 449 450 /* Insert 0 session_id */ 451 *((__be32 *)skb_put(skb, 4)) = 0; 452 453 /* Copy user data into skb */ 454 rc = memcpy_from_msg(skb_put(skb, len), msg, len); 455 if (rc < 0) { 456 kfree_skb(skb); 457 goto error; 458 } 459 460 fl4 = &inet->cork.fl.u.ip4; 461 if (connected) 462 rt = (struct rtable *)__sk_dst_check(sk, 0); 463 464 rcu_read_lock(); 465 if (!rt) { 466 const struct ip_options_rcu *inet_opt; 467 468 inet_opt = rcu_dereference(inet->inet_opt); 469 470 /* Use correct destination address if we have options. */ 471 if (inet_opt && inet_opt->opt.srr) 472 daddr = inet_opt->opt.faddr; 473 474 /* If this fails, retransmit mechanism of transport layer will 475 * keep trying until route appears or the connection times 476 * itself out. 477 */ 478 rt = ip_route_output_ports(sock_net(sk), fl4, sk, 479 daddr, inet->inet_saddr, 480 inet->inet_dport, inet->inet_sport, 481 sk->sk_protocol, RT_CONN_FLAGS(sk), 482 sk->sk_bound_dev_if); 483 if (IS_ERR(rt)) 484 goto no_route; 485 if (connected) { 486 sk_setup_caps(sk, &rt->dst); 487 } else { 488 skb_dst_set(skb, &rt->dst); 489 goto xmit; 490 } 491 } 492 493 /* We don't need to clone dst here, it is guaranteed to not disappear. 494 * __dev_xmit_skb() might force a refcount if needed. 495 */ 496 skb_dst_set_noref(skb, &rt->dst); 497 498 xmit: 499 /* Queue the packet to IP for output */ 500 rc = ip_queue_xmit(sk, skb, &inet->cork.fl); 501 rcu_read_unlock(); 502 503 error: 504 if (rc >= 0) 505 rc = len; 506 507 out: 508 release_sock(sk); 509 return rc; 510 511 no_route: 512 rcu_read_unlock(); 513 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 514 kfree_skb(skb); 515 rc = -EHOSTUNREACH; 516 goto out; 517 } 518 519 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg, 520 size_t len, int flags, int *addr_len) 521 { 522 struct inet_sock *inet = inet_sk(sk); 523 size_t copied = 0; 524 int err = -EOPNOTSUPP; 525 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name); 526 struct sk_buff *skb; 527 528 if (flags & MSG_OOB) 529 goto out; 530 531 skb = skb_recv_datagram(sk, flags, &err); 532 if (!skb) 533 goto out; 534 535 copied = skb->len; 536 if (len < copied) { 537 msg->msg_flags |= MSG_TRUNC; 538 copied = len; 539 } 540 541 err = skb_copy_datagram_msg(skb, 0, msg, copied); 542 if (err) 543 goto done; 544 545 sock_recv_timestamp(msg, sk, skb); 546 547 /* Copy the address. */ 548 if (sin) { 549 sin->sin_family = AF_INET; 550 sin->sin_addr.s_addr = ip_hdr(skb)->saddr; 551 sin->sin_port = 0; 552 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero)); 553 *addr_len = sizeof(*sin); 554 } 555 if (inet->cmsg_flags) 556 ip_cmsg_recv(msg, skb); 557 if (flags & MSG_TRUNC) 558 copied = skb->len; 559 done: 560 skb_free_datagram(sk, skb); 561 out: 562 return err ? err : copied; 563 } 564 565 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg) 566 { 567 struct sk_buff *skb; 568 int amount; 569 570 switch (cmd) { 571 case SIOCOUTQ: 572 amount = sk_wmem_alloc_get(sk); 573 break; 574 case SIOCINQ: 575 spin_lock_bh(&sk->sk_receive_queue.lock); 576 skb = skb_peek(&sk->sk_receive_queue); 577 amount = skb ? skb->len : 0; 578 spin_unlock_bh(&sk->sk_receive_queue.lock); 579 break; 580 581 default: 582 return -ENOIOCTLCMD; 583 } 584 585 return put_user(amount, (int __user *)arg); 586 } 587 EXPORT_SYMBOL_GPL(l2tp_ioctl); 588 589 static struct proto l2tp_ip_prot = { 590 .name = "L2TP/IP", 591 .owner = THIS_MODULE, 592 .init = l2tp_ip_open, 593 .close = l2tp_ip_close, 594 .bind = l2tp_ip_bind, 595 .connect = l2tp_ip_connect, 596 .disconnect = l2tp_ip_disconnect, 597 .ioctl = l2tp_ioctl, 598 .destroy = l2tp_ip_destroy_sock, 599 .setsockopt = ip_setsockopt, 600 .getsockopt = ip_getsockopt, 601 .sendmsg = l2tp_ip_sendmsg, 602 .recvmsg = l2tp_ip_recvmsg, 603 .backlog_rcv = l2tp_ip_backlog_recv, 604 .hash = l2tp_ip_hash, 605 .unhash = l2tp_ip_unhash, 606 .obj_size = sizeof(struct l2tp_ip_sock), 607 }; 608 609 static const struct proto_ops l2tp_ip_ops = { 610 .family = PF_INET, 611 .owner = THIS_MODULE, 612 .release = inet_release, 613 .bind = inet_bind, 614 .connect = inet_dgram_connect, 615 .socketpair = sock_no_socketpair, 616 .accept = sock_no_accept, 617 .getname = l2tp_ip_getname, 618 .poll = datagram_poll, 619 .ioctl = inet_ioctl, 620 .gettstamp = sock_gettstamp, 621 .listen = sock_no_listen, 622 .shutdown = inet_shutdown, 623 .setsockopt = sock_common_setsockopt, 624 .getsockopt = sock_common_getsockopt, 625 .sendmsg = inet_sendmsg, 626 .recvmsg = sock_common_recvmsg, 627 .mmap = sock_no_mmap, 628 .sendpage = sock_no_sendpage, 629 }; 630 631 static struct inet_protosw l2tp_ip_protosw = { 632 .type = SOCK_DGRAM, 633 .protocol = IPPROTO_L2TP, 634 .prot = &l2tp_ip_prot, 635 .ops = &l2tp_ip_ops, 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 pr_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"); 679 680 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like 681 * enums 682 */ 683 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP); 684 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP); 685