1 /* 2 * L2TPv3 IP encapsulation support for IPv6 3 * 4 * Copyright (c) 2012 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 <linux/icmp.h> 15 #include <linux/module.h> 16 #include <linux/skbuff.h> 17 #include <linux/random.h> 18 #include <linux/socket.h> 19 #include <linux/l2tp.h> 20 #include <linux/in.h> 21 #include <linux/in6.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 <net/transp_v6.h> 33 #include <net/addrconf.h> 34 #include <net/ip6_route.h> 35 36 #include "l2tp_core.h" 37 38 struct l2tp_ip6_sock { 39 /* inet_sock has to be the first member of l2tp_ip6_sock */ 40 struct inet_sock inet; 41 42 u32 conn_id; 43 u32 peer_conn_id; 44 45 /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see 46 inet6_sk_generic */ 47 struct ipv6_pinfo inet6; 48 }; 49 50 static DEFINE_RWLOCK(l2tp_ip6_lock); 51 static struct hlist_head l2tp_ip6_table; 52 static struct hlist_head l2tp_ip6_bind_table; 53 54 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk) 55 { 56 return (struct l2tp_ip6_sock *)sk; 57 } 58 59 static struct sock *__l2tp_ip6_bind_lookup(struct net *net, 60 struct in6_addr *laddr, 61 int dif, u32 tunnel_id) 62 { 63 struct sock *sk; 64 65 sk_for_each_bound(sk, &l2tp_ip6_bind_table) { 66 const struct in6_addr *addr = inet6_rcv_saddr(sk); 67 struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk); 68 69 if (l2tp == NULL) 70 continue; 71 72 if ((l2tp->conn_id == tunnel_id) && 73 net_eq(sock_net(sk), net) && 74 !(addr && ipv6_addr_equal(addr, laddr)) && 75 !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)) 76 goto found; 77 } 78 79 sk = NULL; 80 found: 81 return sk; 82 } 83 84 static inline struct sock *l2tp_ip6_bind_lookup(struct net *net, 85 struct in6_addr *laddr, 86 int dif, u32 tunnel_id) 87 { 88 struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id); 89 if (sk) 90 sock_hold(sk); 91 92 return sk; 93 } 94 95 /* When processing receive frames, there are two cases to 96 * consider. Data frames consist of a non-zero session-id and an 97 * optional cookie. Control frames consist of a regular L2TP header 98 * preceded by 32-bits of zeros. 99 * 100 * L2TPv3 Session Header Over IP 101 * 102 * 0 1 2 3 103 * 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 1 104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 105 * | Session ID | 106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 107 * | Cookie (optional, maximum 64 bits)... 108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 109 * | 110 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 111 * 112 * L2TPv3 Control Message Header Over IP 113 * 114 * 0 1 2 3 115 * 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 1 116 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 117 * | (32 bits of zeros) | 118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 119 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length | 120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 121 * | Control Connection ID | 122 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 123 * | Ns | Nr | 124 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 125 * 126 * All control frames are passed to userspace. 127 */ 128 static int l2tp_ip6_recv(struct sk_buff *skb) 129 { 130 struct sock *sk; 131 u32 session_id; 132 u32 tunnel_id; 133 unsigned char *ptr, *optr; 134 struct l2tp_session *session; 135 struct l2tp_tunnel *tunnel = NULL; 136 int length; 137 138 /* Point to L2TP header */ 139 optr = ptr = skb->data; 140 141 if (!pskb_may_pull(skb, 4)) 142 goto discard; 143 144 session_id = ntohl(*((__be32 *) ptr)); 145 ptr += 4; 146 147 /* RFC3931: L2TP/IP packets have the first 4 bytes containing 148 * the session_id. If it is 0, the packet is a L2TP control 149 * frame and the session_id value can be discarded. 150 */ 151 if (session_id == 0) { 152 __skb_pull(skb, 4); 153 goto pass_up; 154 } 155 156 /* Ok, this is a data packet. Lookup the session. */ 157 session = l2tp_session_find(&init_net, NULL, session_id); 158 if (session == NULL) 159 goto discard; 160 161 tunnel = session->tunnel; 162 if (tunnel == NULL) 163 goto discard; 164 165 /* Trace packet contents, if enabled */ 166 if (tunnel->debug & L2TP_MSG_DATA) { 167 length = min(32u, skb->len); 168 if (!pskb_may_pull(skb, length)) 169 goto discard; 170 171 pr_debug("%s: ip recv\n", tunnel->name); 172 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length); 173 } 174 175 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, 176 tunnel->recv_payload_hook); 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 ipv6hdr *iph = ipv6_hdr(skb); 193 194 read_lock_bh(&l2tp_ip6_lock); 195 sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr, 196 0, tunnel_id); 197 read_unlock_bh(&l2tp_ip6_lock); 198 } 199 200 if (sk == NULL) 201 goto discard; 202 203 sock_hold(sk); 204 205 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 206 goto discard_put; 207 208 nf_reset(skb); 209 210 return sk_receive_skb(sk, skb, 1); 211 212 discard_put: 213 sock_put(sk); 214 215 discard: 216 kfree_skb(skb); 217 return 0; 218 } 219 220 static int l2tp_ip6_open(struct sock *sk) 221 { 222 /* Prevent autobind. We don't have ports. */ 223 inet_sk(sk)->inet_num = IPPROTO_L2TP; 224 225 write_lock_bh(&l2tp_ip6_lock); 226 sk_add_node(sk, &l2tp_ip6_table); 227 write_unlock_bh(&l2tp_ip6_lock); 228 229 return 0; 230 } 231 232 static void l2tp_ip6_close(struct sock *sk, long timeout) 233 { 234 write_lock_bh(&l2tp_ip6_lock); 235 hlist_del_init(&sk->sk_bind_node); 236 sk_del_node_init(sk); 237 write_unlock_bh(&l2tp_ip6_lock); 238 239 sk_common_release(sk); 240 } 241 242 static void l2tp_ip6_destroy_sock(struct sock *sk) 243 { 244 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); 245 246 lock_sock(sk); 247 ip6_flush_pending_frames(sk); 248 release_sock(sk); 249 250 if (tunnel) { 251 l2tp_tunnel_closeall(tunnel); 252 sock_put(sk); 253 } 254 255 inet6_destroy_sock(sk); 256 } 257 258 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 259 { 260 struct inet_sock *inet = inet_sk(sk); 261 struct ipv6_pinfo *np = inet6_sk(sk); 262 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr; 263 __be32 v4addr = 0; 264 int addr_type; 265 int err; 266 267 if (!sock_flag(sk, SOCK_ZAPPED)) 268 return -EINVAL; 269 if (addr->l2tp_family != AF_INET6) 270 return -EINVAL; 271 if (addr_len < sizeof(*addr)) 272 return -EINVAL; 273 274 addr_type = ipv6_addr_type(&addr->l2tp_addr); 275 276 /* l2tp_ip6 sockets are IPv6 only */ 277 if (addr_type == IPV6_ADDR_MAPPED) 278 return -EADDRNOTAVAIL; 279 280 /* L2TP is point-point, not multicast */ 281 if (addr_type & IPV6_ADDR_MULTICAST) 282 return -EADDRNOTAVAIL; 283 284 err = -EADDRINUSE; 285 read_lock_bh(&l2tp_ip6_lock); 286 if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr, 287 sk->sk_bound_dev_if, addr->l2tp_conn_id)) 288 goto out_in_use; 289 read_unlock_bh(&l2tp_ip6_lock); 290 291 lock_sock(sk); 292 293 err = -EINVAL; 294 if (sk->sk_state != TCP_CLOSE) 295 goto out_unlock; 296 297 /* Check if the address belongs to the host. */ 298 rcu_read_lock(); 299 if (addr_type != IPV6_ADDR_ANY) { 300 struct net_device *dev = NULL; 301 302 if (addr_type & IPV6_ADDR_LINKLOCAL) { 303 if (addr_len >= sizeof(struct sockaddr_in6) && 304 addr->l2tp_scope_id) { 305 /* Override any existing binding, if another 306 * one is supplied by user. 307 */ 308 sk->sk_bound_dev_if = addr->l2tp_scope_id; 309 } 310 311 /* Binding to link-local address requires an 312 interface */ 313 if (!sk->sk_bound_dev_if) 314 goto out_unlock_rcu; 315 316 err = -ENODEV; 317 dev = dev_get_by_index_rcu(sock_net(sk), 318 sk->sk_bound_dev_if); 319 if (!dev) 320 goto out_unlock_rcu; 321 } 322 323 /* ipv4 addr of the socket is invalid. Only the 324 * unspecified and mapped address have a v4 equivalent. 325 */ 326 v4addr = LOOPBACK4_IPV6; 327 err = -EADDRNOTAVAIL; 328 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0)) 329 goto out_unlock_rcu; 330 } 331 rcu_read_unlock(); 332 333 inet->inet_rcv_saddr = inet->inet_saddr = v4addr; 334 sk->sk_v6_rcv_saddr = addr->l2tp_addr; 335 np->saddr = addr->l2tp_addr; 336 337 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id; 338 339 write_lock_bh(&l2tp_ip6_lock); 340 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 341 sk_del_node_init(sk); 342 write_unlock_bh(&l2tp_ip6_lock); 343 344 sock_reset_flag(sk, SOCK_ZAPPED); 345 release_sock(sk); 346 return 0; 347 348 out_unlock_rcu: 349 rcu_read_unlock(); 350 out_unlock: 351 release_sock(sk); 352 return err; 353 354 out_in_use: 355 read_unlock_bh(&l2tp_ip6_lock); 356 return err; 357 } 358 359 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr, 360 int addr_len) 361 { 362 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr; 363 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr; 364 struct in6_addr *daddr; 365 int addr_type; 366 int rc; 367 368 if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */ 369 return -EINVAL; 370 371 if (addr_len < sizeof(*lsa)) 372 return -EINVAL; 373 374 if (usin->sin6_family != AF_INET6) 375 return -EINVAL; 376 377 addr_type = ipv6_addr_type(&usin->sin6_addr); 378 if (addr_type & IPV6_ADDR_MULTICAST) 379 return -EINVAL; 380 381 if (addr_type & IPV6_ADDR_MAPPED) { 382 daddr = &usin->sin6_addr; 383 if (ipv4_is_multicast(daddr->s6_addr32[3])) 384 return -EINVAL; 385 } 386 387 rc = ip6_datagram_connect(sk, uaddr, addr_len); 388 389 lock_sock(sk); 390 391 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 392 393 write_lock_bh(&l2tp_ip6_lock); 394 hlist_del_init(&sk->sk_bind_node); 395 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 396 write_unlock_bh(&l2tp_ip6_lock); 397 398 release_sock(sk); 399 400 return rc; 401 } 402 403 static int l2tp_ip6_disconnect(struct sock *sk, int flags) 404 { 405 if (sock_flag(sk, SOCK_ZAPPED)) 406 return 0; 407 408 return udp_disconnect(sk, flags); 409 } 410 411 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr, 412 int *uaddr_len, int peer) 413 { 414 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; 415 struct sock *sk = sock->sk; 416 struct ipv6_pinfo *np = inet6_sk(sk); 417 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk); 418 419 lsa->l2tp_family = AF_INET6; 420 lsa->l2tp_flowinfo = 0; 421 lsa->l2tp_scope_id = 0; 422 lsa->l2tp_unused = 0; 423 if (peer) { 424 if (!lsk->peer_conn_id) 425 return -ENOTCONN; 426 lsa->l2tp_conn_id = lsk->peer_conn_id; 427 lsa->l2tp_addr = sk->sk_v6_daddr; 428 if (np->sndflow) 429 lsa->l2tp_flowinfo = np->flow_label; 430 } else { 431 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 432 lsa->l2tp_addr = np->saddr; 433 else 434 lsa->l2tp_addr = sk->sk_v6_rcv_saddr; 435 436 lsa->l2tp_conn_id = lsk->conn_id; 437 } 438 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 439 lsa->l2tp_scope_id = sk->sk_bound_dev_if; 440 *uaddr_len = sizeof(*lsa); 441 return 0; 442 } 443 444 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb) 445 { 446 int rc; 447 448 /* Charge it to the socket, dropping if the queue is full. */ 449 rc = sock_queue_rcv_skb(sk, skb); 450 if (rc < 0) 451 goto drop; 452 453 return 0; 454 455 drop: 456 IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS); 457 kfree_skb(skb); 458 return -1; 459 } 460 461 static int l2tp_ip6_push_pending_frames(struct sock *sk) 462 { 463 struct sk_buff *skb; 464 __be32 *transhdr = NULL; 465 int err = 0; 466 467 skb = skb_peek(&sk->sk_write_queue); 468 if (skb == NULL) 469 goto out; 470 471 transhdr = (__be32 *)skb_transport_header(skb); 472 *transhdr = 0; 473 474 err = ip6_push_pending_frames(sk); 475 476 out: 477 return err; 478 } 479 480 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 481 * control frames. 482 */ 483 static int l2tp_ip6_sendmsg(struct kiocb *iocb, struct sock *sk, 484 struct msghdr *msg, size_t len) 485 { 486 struct ipv6_txoptions opt_space; 487 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 488 struct in6_addr *daddr, *final_p, final; 489 struct ipv6_pinfo *np = inet6_sk(sk); 490 struct ipv6_txoptions *opt = NULL; 491 struct ip6_flowlabel *flowlabel = NULL; 492 struct dst_entry *dst = NULL; 493 struct flowi6 fl6; 494 int addr_len = msg->msg_namelen; 495 int hlimit = -1; 496 int tclass = -1; 497 int dontfrag = -1; 498 int transhdrlen = 4; /* zero session-id */ 499 int ulen = len + transhdrlen; 500 int err; 501 502 /* Rough check on arithmetic overflow, 503 better check is made in ip6_append_data(). 504 */ 505 if (len > INT_MAX) 506 return -EMSGSIZE; 507 508 /* Mirror BSD error message compatibility */ 509 if (msg->msg_flags & MSG_OOB) 510 return -EOPNOTSUPP; 511 512 /* 513 * Get and verify the address. 514 */ 515 memset(&fl6, 0, sizeof(fl6)); 516 517 fl6.flowi6_mark = sk->sk_mark; 518 519 if (lsa) { 520 if (addr_len < SIN6_LEN_RFC2133) 521 return -EINVAL; 522 523 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6) 524 return -EAFNOSUPPORT; 525 526 daddr = &lsa->l2tp_addr; 527 if (np->sndflow) { 528 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK; 529 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) { 530 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 531 if (flowlabel == NULL) 532 return -EINVAL; 533 } 534 } 535 536 /* 537 * Otherwise it will be difficult to maintain 538 * sk->sk_dst_cache. 539 */ 540 if (sk->sk_state == TCP_ESTABLISHED && 541 ipv6_addr_equal(daddr, &sk->sk_v6_daddr)) 542 daddr = &sk->sk_v6_daddr; 543 544 if (addr_len >= sizeof(struct sockaddr_in6) && 545 lsa->l2tp_scope_id && 546 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL) 547 fl6.flowi6_oif = lsa->l2tp_scope_id; 548 } else { 549 if (sk->sk_state != TCP_ESTABLISHED) 550 return -EDESTADDRREQ; 551 552 daddr = &sk->sk_v6_daddr; 553 fl6.flowlabel = np->flow_label; 554 } 555 556 if (fl6.flowi6_oif == 0) 557 fl6.flowi6_oif = sk->sk_bound_dev_if; 558 559 if (msg->msg_controllen) { 560 opt = &opt_space; 561 memset(opt, 0, sizeof(struct ipv6_txoptions)); 562 opt->tot_len = sizeof(struct ipv6_txoptions); 563 564 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt, 565 &hlimit, &tclass, &dontfrag); 566 if (err < 0) { 567 fl6_sock_release(flowlabel); 568 return err; 569 } 570 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) { 571 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 572 if (flowlabel == NULL) 573 return -EINVAL; 574 } 575 if (!(opt->opt_nflen|opt->opt_flen)) 576 opt = NULL; 577 } 578 579 if (opt == NULL) 580 opt = np->opt; 581 if (flowlabel) 582 opt = fl6_merge_options(&opt_space, flowlabel, opt); 583 opt = ipv6_fixup_options(&opt_space, opt); 584 585 fl6.flowi6_proto = sk->sk_protocol; 586 if (!ipv6_addr_any(daddr)) 587 fl6.daddr = *daddr; 588 else 589 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ 590 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr)) 591 fl6.saddr = np->saddr; 592 593 final_p = fl6_update_dst(&fl6, opt, &final); 594 595 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 596 fl6.flowi6_oif = np->mcast_oif; 597 else if (!fl6.flowi6_oif) 598 fl6.flowi6_oif = np->ucast_oif; 599 600 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6)); 601 602 dst = ip6_dst_lookup_flow(sk, &fl6, final_p); 603 if (IS_ERR(dst)) { 604 err = PTR_ERR(dst); 605 goto out; 606 } 607 608 if (hlimit < 0) 609 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 610 611 if (tclass < 0) 612 tclass = np->tclass; 613 614 if (dontfrag < 0) 615 dontfrag = np->dontfrag; 616 617 if (msg->msg_flags & MSG_CONFIRM) 618 goto do_confirm; 619 620 back_from_confirm: 621 lock_sock(sk); 622 err = ip6_append_data(sk, ip_generic_getfrag, msg, 623 ulen, transhdrlen, hlimit, tclass, opt, 624 &fl6, (struct rt6_info *)dst, 625 msg->msg_flags, dontfrag); 626 if (err) 627 ip6_flush_pending_frames(sk); 628 else if (!(msg->msg_flags & MSG_MORE)) 629 err = l2tp_ip6_push_pending_frames(sk); 630 release_sock(sk); 631 done: 632 dst_release(dst); 633 out: 634 fl6_sock_release(flowlabel); 635 636 return err < 0 ? err : len; 637 638 do_confirm: 639 dst_confirm(dst); 640 if (!(msg->msg_flags & MSG_PROBE) || len) 641 goto back_from_confirm; 642 err = 0; 643 goto done; 644 } 645 646 static int l2tp_ip6_recvmsg(struct kiocb *iocb, struct sock *sk, 647 struct msghdr *msg, size_t len, int noblock, 648 int flags, int *addr_len) 649 { 650 struct ipv6_pinfo *np = inet6_sk(sk); 651 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 652 size_t copied = 0; 653 int err = -EOPNOTSUPP; 654 struct sk_buff *skb; 655 656 if (flags & MSG_OOB) 657 goto out; 658 659 if (addr_len) 660 *addr_len = sizeof(*lsa); 661 662 if (flags & MSG_ERRQUEUE) 663 return ipv6_recv_error(sk, msg, len, addr_len); 664 665 skb = skb_recv_datagram(sk, flags, noblock, &err); 666 if (!skb) 667 goto out; 668 669 copied = skb->len; 670 if (len < copied) { 671 msg->msg_flags |= MSG_TRUNC; 672 copied = len; 673 } 674 675 err = skb_copy_datagram_msg(skb, 0, msg, copied); 676 if (err) 677 goto done; 678 679 sock_recv_timestamp(msg, sk, skb); 680 681 /* Copy the address. */ 682 if (lsa) { 683 lsa->l2tp_family = AF_INET6; 684 lsa->l2tp_unused = 0; 685 lsa->l2tp_addr = ipv6_hdr(skb)->saddr; 686 lsa->l2tp_flowinfo = 0; 687 lsa->l2tp_scope_id = 0; 688 lsa->l2tp_conn_id = 0; 689 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 690 lsa->l2tp_scope_id = inet6_iif(skb); 691 } 692 693 if (np->rxopt.all) 694 ip6_datagram_recv_ctl(sk, msg, skb); 695 696 if (flags & MSG_TRUNC) 697 copied = skb->len; 698 done: 699 skb_free_datagram(sk, skb); 700 out: 701 return err ? err : copied; 702 } 703 704 static struct proto l2tp_ip6_prot = { 705 .name = "L2TP/IPv6", 706 .owner = THIS_MODULE, 707 .init = l2tp_ip6_open, 708 .close = l2tp_ip6_close, 709 .bind = l2tp_ip6_bind, 710 .connect = l2tp_ip6_connect, 711 .disconnect = l2tp_ip6_disconnect, 712 .ioctl = udp_ioctl, 713 .destroy = l2tp_ip6_destroy_sock, 714 .setsockopt = ipv6_setsockopt, 715 .getsockopt = ipv6_getsockopt, 716 .sendmsg = l2tp_ip6_sendmsg, 717 .recvmsg = l2tp_ip6_recvmsg, 718 .backlog_rcv = l2tp_ip6_backlog_recv, 719 .hash = inet_hash, 720 .unhash = inet_unhash, 721 .obj_size = sizeof(struct l2tp_ip6_sock), 722 #ifdef CONFIG_COMPAT 723 .compat_setsockopt = compat_ipv6_setsockopt, 724 .compat_getsockopt = compat_ipv6_getsockopt, 725 #endif 726 }; 727 728 static const struct proto_ops l2tp_ip6_ops = { 729 .family = PF_INET6, 730 .owner = THIS_MODULE, 731 .release = inet6_release, 732 .bind = inet6_bind, 733 .connect = inet_dgram_connect, 734 .socketpair = sock_no_socketpair, 735 .accept = sock_no_accept, 736 .getname = l2tp_ip6_getname, 737 .poll = datagram_poll, 738 .ioctl = inet6_ioctl, 739 .listen = sock_no_listen, 740 .shutdown = inet_shutdown, 741 .setsockopt = sock_common_setsockopt, 742 .getsockopt = sock_common_getsockopt, 743 .sendmsg = inet_sendmsg, 744 .recvmsg = sock_common_recvmsg, 745 .mmap = sock_no_mmap, 746 .sendpage = sock_no_sendpage, 747 #ifdef CONFIG_COMPAT 748 .compat_setsockopt = compat_sock_common_setsockopt, 749 .compat_getsockopt = compat_sock_common_getsockopt, 750 #endif 751 }; 752 753 static struct inet_protosw l2tp_ip6_protosw = { 754 .type = SOCK_DGRAM, 755 .protocol = IPPROTO_L2TP, 756 .prot = &l2tp_ip6_prot, 757 .ops = &l2tp_ip6_ops, 758 }; 759 760 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = { 761 .handler = l2tp_ip6_recv, 762 }; 763 764 static int __init l2tp_ip6_init(void) 765 { 766 int err; 767 768 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n"); 769 770 err = proto_register(&l2tp_ip6_prot, 1); 771 if (err != 0) 772 goto out; 773 774 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 775 if (err) 776 goto out1; 777 778 inet6_register_protosw(&l2tp_ip6_protosw); 779 return 0; 780 781 out1: 782 proto_unregister(&l2tp_ip6_prot); 783 out: 784 return err; 785 } 786 787 static void __exit l2tp_ip6_exit(void) 788 { 789 inet6_unregister_protosw(&l2tp_ip6_protosw); 790 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 791 proto_unregister(&l2tp_ip6_prot); 792 } 793 794 module_init(l2tp_ip6_init); 795 module_exit(l2tp_ip6_exit); 796 797 MODULE_LICENSE("GPL"); 798 MODULE_AUTHOR("Chris Elston <celston@katalix.com>"); 799 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6"); 800 MODULE_VERSION("1.0"); 801 802 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like 803 * enums 804 */ 805 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP); 806