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/inet6_hashtables.h> 29 #include <net/tcp_states.h> 30 #include <net/protocol.h> 31 #include <net/xfrm.h> 32 33 #include <net/transp_v6.h> 34 #include <net/addrconf.h> 35 #include <net/ip6_route.h> 36 37 #include "l2tp_core.h" 38 39 struct l2tp_ip6_sock { 40 /* inet_sock has to be the first member of l2tp_ip6_sock */ 41 struct inet_sock inet; 42 43 u32 conn_id; 44 u32 peer_conn_id; 45 46 /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see 47 inet6_sk_generic */ 48 struct ipv6_pinfo inet6; 49 }; 50 51 static DEFINE_RWLOCK(l2tp_ip6_lock); 52 static struct hlist_head l2tp_ip6_table; 53 static struct hlist_head l2tp_ip6_bind_table; 54 55 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk) 56 { 57 return (struct l2tp_ip6_sock *)sk; 58 } 59 60 static struct sock *__l2tp_ip6_bind_lookup(struct net *net, 61 struct in6_addr *laddr, 62 const struct in6_addr *raddr, 63 int dif, u32 tunnel_id) 64 { 65 struct sock *sk; 66 67 sk_for_each_bound(sk, &l2tp_ip6_bind_table) { 68 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk); 69 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr; 70 struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk); 71 72 if (l2tp == NULL) 73 continue; 74 75 if ((l2tp->conn_id == tunnel_id) && 76 net_eq(sock_net(sk), net) && 77 (!sk_laddr || ipv6_addr_any(sk_laddr) || ipv6_addr_equal(sk_laddr, laddr)) && 78 (!raddr || ipv6_addr_any(sk_raddr) || ipv6_addr_equal(sk_raddr, raddr)) && 79 (!sk->sk_bound_dev_if || !dif || 80 sk->sk_bound_dev_if == dif)) 81 goto found; 82 } 83 84 sk = NULL; 85 found: 86 return sk; 87 } 88 89 /* When processing receive frames, there are two cases to 90 * consider. Data frames consist of a non-zero session-id and an 91 * optional cookie. Control frames consist of a regular L2TP header 92 * preceded by 32-bits of zeros. 93 * 94 * L2TPv3 Session Header Over IP 95 * 96 * 0 1 2 3 97 * 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 98 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 99 * | Session ID | 100 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 101 * | Cookie (optional, maximum 64 bits)... 102 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 103 * | 104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 105 * 106 * L2TPv3 Control Message Header Over IP 107 * 108 * 0 1 2 3 109 * 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 1 110 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 111 * | (32 bits of zeros) | 112 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 113 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length | 114 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 115 * | Control Connection ID | 116 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 117 * | Ns | Nr | 118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 119 * 120 * All control frames are passed to userspace. 121 */ 122 static int l2tp_ip6_recv(struct sk_buff *skb) 123 { 124 struct net *net = dev_net(skb->dev); 125 struct sock *sk; 126 u32 session_id; 127 u32 tunnel_id; 128 unsigned char *ptr, *optr; 129 struct l2tp_session *session; 130 struct l2tp_tunnel *tunnel = NULL; 131 int length; 132 133 if (!pskb_may_pull(skb, 4)) 134 goto discard; 135 136 /* Point to L2TP header */ 137 optr = ptr = skb->data; 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(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 /* Point to L2TP header */ 166 optr = ptr = skb->data; 167 ptr += 4; 168 pr_debug("%s: ip recv\n", tunnel->name); 169 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length); 170 } 171 172 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, 173 tunnel->recv_payload_hook); 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 tunnel = l2tp_tunnel_find(net, tunnel_id); 186 if (tunnel != NULL) 187 sk = tunnel->sock; 188 else { 189 struct ipv6hdr *iph = ipv6_hdr(skb); 190 191 read_lock_bh(&l2tp_ip6_lock); 192 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr, 193 inet6_iif(skb), tunnel_id); 194 if (!sk) { 195 read_unlock_bh(&l2tp_ip6_lock); 196 goto discard; 197 } 198 199 sock_hold(sk); 200 read_unlock_bh(&l2tp_ip6_lock); 201 } 202 203 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 204 goto discard_put; 205 206 nf_reset(skb); 207 208 return sk_receive_skb(sk, skb, 1); 209 210 discard_put: 211 sock_put(sk); 212 213 discard: 214 kfree_skb(skb); 215 return 0; 216 } 217 218 static int l2tp_ip6_open(struct sock *sk) 219 { 220 /* Prevent autobind. We don't have ports. */ 221 inet_sk(sk)->inet_num = IPPROTO_L2TP; 222 223 write_lock_bh(&l2tp_ip6_lock); 224 sk_add_node(sk, &l2tp_ip6_table); 225 write_unlock_bh(&l2tp_ip6_lock); 226 227 return 0; 228 } 229 230 static void l2tp_ip6_close(struct sock *sk, long timeout) 231 { 232 write_lock_bh(&l2tp_ip6_lock); 233 hlist_del_init(&sk->sk_bind_node); 234 sk_del_node_init(sk); 235 write_unlock_bh(&l2tp_ip6_lock); 236 237 sk_common_release(sk); 238 } 239 240 static void l2tp_ip6_destroy_sock(struct sock *sk) 241 { 242 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); 243 244 lock_sock(sk); 245 ip6_flush_pending_frames(sk); 246 release_sock(sk); 247 248 if (tunnel) { 249 l2tp_tunnel_closeall(tunnel); 250 sock_put(sk); 251 } 252 253 inet6_destroy_sock(sk); 254 } 255 256 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 257 { 258 struct inet_sock *inet = inet_sk(sk); 259 struct ipv6_pinfo *np = inet6_sk(sk); 260 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr; 261 struct net *net = sock_net(sk); 262 __be32 v4addr = 0; 263 int bound_dev_if; 264 int addr_type; 265 int err; 266 267 if (addr->l2tp_family != AF_INET6) 268 return -EINVAL; 269 if (addr_len < sizeof(*addr)) 270 return -EINVAL; 271 272 addr_type = ipv6_addr_type(&addr->l2tp_addr); 273 274 /* l2tp_ip6 sockets are IPv6 only */ 275 if (addr_type == IPV6_ADDR_MAPPED) 276 return -EADDRNOTAVAIL; 277 278 /* L2TP is point-point, not multicast */ 279 if (addr_type & IPV6_ADDR_MULTICAST) 280 return -EADDRNOTAVAIL; 281 282 lock_sock(sk); 283 284 err = -EINVAL; 285 if (!sock_flag(sk, SOCK_ZAPPED)) 286 goto out_unlock; 287 288 if (sk->sk_state != TCP_CLOSE) 289 goto out_unlock; 290 291 bound_dev_if = sk->sk_bound_dev_if; 292 293 /* Check if the address belongs to the host. */ 294 rcu_read_lock(); 295 if (addr_type != IPV6_ADDR_ANY) { 296 struct net_device *dev = NULL; 297 298 if (addr_type & IPV6_ADDR_LINKLOCAL) { 299 if (addr->l2tp_scope_id) 300 bound_dev_if = addr->l2tp_scope_id; 301 302 /* Binding to link-local address requires an 303 * interface. 304 */ 305 if (!bound_dev_if) 306 goto out_unlock_rcu; 307 308 err = -ENODEV; 309 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if); 310 if (!dev) 311 goto out_unlock_rcu; 312 } 313 314 /* ipv4 addr of the socket is invalid. Only the 315 * unspecified and mapped address have a v4 equivalent. 316 */ 317 v4addr = LOOPBACK4_IPV6; 318 err = -EADDRNOTAVAIL; 319 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0)) 320 goto out_unlock_rcu; 321 } 322 rcu_read_unlock(); 323 324 write_lock_bh(&l2tp_ip6_lock); 325 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if, 326 addr->l2tp_conn_id)) { 327 write_unlock_bh(&l2tp_ip6_lock); 328 err = -EADDRINUSE; 329 goto out_unlock; 330 } 331 332 inet->inet_saddr = v4addr; 333 inet->inet_rcv_saddr = v4addr; 334 sk->sk_bound_dev_if = bound_dev_if; 335 sk->sk_v6_rcv_saddr = addr->l2tp_addr; 336 np->saddr = addr->l2tp_addr; 337 338 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id; 339 340 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); 352 353 return err; 354 } 355 356 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr, 357 int addr_len) 358 { 359 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr; 360 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr; 361 struct in6_addr *daddr; 362 int addr_type; 363 int rc; 364 365 if (addr_len < sizeof(*lsa)) 366 return -EINVAL; 367 368 if (usin->sin6_family != AF_INET6) 369 return -EINVAL; 370 371 addr_type = ipv6_addr_type(&usin->sin6_addr); 372 if (addr_type & IPV6_ADDR_MULTICAST) 373 return -EINVAL; 374 375 if (addr_type & IPV6_ADDR_MAPPED) { 376 daddr = &usin->sin6_addr; 377 if (ipv4_is_multicast(daddr->s6_addr32[3])) 378 return -EINVAL; 379 } 380 381 lock_sock(sk); 382 383 /* Must bind first - autobinding does not work */ 384 if (sock_flag(sk, SOCK_ZAPPED)) { 385 rc = -EINVAL; 386 goto out_sk; 387 } 388 389 rc = __ip6_datagram_connect(sk, uaddr, addr_len); 390 if (rc < 0) 391 goto out_sk; 392 393 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 394 395 write_lock_bh(&l2tp_ip6_lock); 396 hlist_del_init(&sk->sk_bind_node); 397 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 398 write_unlock_bh(&l2tp_ip6_lock); 399 400 out_sk: 401 release_sock(sk); 402 403 return rc; 404 } 405 406 static int l2tp_ip6_disconnect(struct sock *sk, int flags) 407 { 408 if (sock_flag(sk, SOCK_ZAPPED)) 409 return 0; 410 411 return __udp_disconnect(sk, flags); 412 } 413 414 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr, 415 int *uaddr_len, int peer) 416 { 417 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; 418 struct sock *sk = sock->sk; 419 struct ipv6_pinfo *np = inet6_sk(sk); 420 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk); 421 422 lsa->l2tp_family = AF_INET6; 423 lsa->l2tp_flowinfo = 0; 424 lsa->l2tp_scope_id = 0; 425 lsa->l2tp_unused = 0; 426 if (peer) { 427 if (!lsk->peer_conn_id) 428 return -ENOTCONN; 429 lsa->l2tp_conn_id = lsk->peer_conn_id; 430 lsa->l2tp_addr = sk->sk_v6_daddr; 431 if (np->sndflow) 432 lsa->l2tp_flowinfo = np->flow_label; 433 } else { 434 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 435 lsa->l2tp_addr = np->saddr; 436 else 437 lsa->l2tp_addr = sk->sk_v6_rcv_saddr; 438 439 lsa->l2tp_conn_id = lsk->conn_id; 440 } 441 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 442 lsa->l2tp_scope_id = sk->sk_bound_dev_if; 443 *uaddr_len = sizeof(*lsa); 444 return 0; 445 } 446 447 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb) 448 { 449 int rc; 450 451 /* Charge it to the socket, dropping if the queue is full. */ 452 rc = sock_queue_rcv_skb(sk, skb); 453 if (rc < 0) 454 goto drop; 455 456 return 0; 457 458 drop: 459 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); 460 kfree_skb(skb); 461 return -1; 462 } 463 464 static int l2tp_ip6_push_pending_frames(struct sock *sk) 465 { 466 struct sk_buff *skb; 467 __be32 *transhdr = NULL; 468 int err = 0; 469 470 skb = skb_peek(&sk->sk_write_queue); 471 if (skb == NULL) 472 goto out; 473 474 transhdr = (__be32 *)skb_transport_header(skb); 475 *transhdr = 0; 476 477 err = ip6_push_pending_frames(sk); 478 479 out: 480 return err; 481 } 482 483 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 484 * control frames. 485 */ 486 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 487 { 488 struct ipv6_txoptions opt_space; 489 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 490 struct in6_addr *daddr, *final_p, final; 491 struct ipv6_pinfo *np = inet6_sk(sk); 492 struct ipv6_txoptions *opt_to_free = NULL; 493 struct ipv6_txoptions *opt = NULL; 494 struct ip6_flowlabel *flowlabel = NULL; 495 struct dst_entry *dst = NULL; 496 struct flowi6 fl6; 497 struct sockcm_cookie sockc_unused = {0}; 498 struct ipcm6_cookie ipc6; 499 int addr_len = msg->msg_namelen; 500 int transhdrlen = 4; /* zero session-id */ 501 int ulen = len + transhdrlen; 502 int err; 503 504 /* Rough check on arithmetic overflow, 505 better check is made in ip6_append_data(). 506 */ 507 if (len > INT_MAX) 508 return -EMSGSIZE; 509 510 /* Mirror BSD error message compatibility */ 511 if (msg->msg_flags & MSG_OOB) 512 return -EOPNOTSUPP; 513 514 /* 515 * Get and verify the address. 516 */ 517 memset(&fl6, 0, sizeof(fl6)); 518 519 fl6.flowi6_mark = sk->sk_mark; 520 fl6.flowi6_uid = sk->sk_uid; 521 522 ipc6.hlimit = -1; 523 ipc6.tclass = -1; 524 ipc6.dontfrag = -1; 525 526 if (lsa) { 527 if (addr_len < SIN6_LEN_RFC2133) 528 return -EINVAL; 529 530 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6) 531 return -EAFNOSUPPORT; 532 533 daddr = &lsa->l2tp_addr; 534 if (np->sndflow) { 535 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK; 536 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) { 537 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 538 if (flowlabel == NULL) 539 return -EINVAL; 540 } 541 } 542 543 /* 544 * Otherwise it will be difficult to maintain 545 * sk->sk_dst_cache. 546 */ 547 if (sk->sk_state == TCP_ESTABLISHED && 548 ipv6_addr_equal(daddr, &sk->sk_v6_daddr)) 549 daddr = &sk->sk_v6_daddr; 550 551 if (addr_len >= sizeof(struct sockaddr_in6) && 552 lsa->l2tp_scope_id && 553 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL) 554 fl6.flowi6_oif = lsa->l2tp_scope_id; 555 } else { 556 if (sk->sk_state != TCP_ESTABLISHED) 557 return -EDESTADDRREQ; 558 559 daddr = &sk->sk_v6_daddr; 560 fl6.flowlabel = np->flow_label; 561 } 562 563 if (fl6.flowi6_oif == 0) 564 fl6.flowi6_oif = sk->sk_bound_dev_if; 565 566 if (msg->msg_controllen) { 567 opt = &opt_space; 568 memset(opt, 0, sizeof(struct ipv6_txoptions)); 569 opt->tot_len = sizeof(struct ipv6_txoptions); 570 ipc6.opt = opt; 571 572 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6, 573 &sockc_unused); 574 if (err < 0) { 575 fl6_sock_release(flowlabel); 576 return err; 577 } 578 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) { 579 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 580 if (flowlabel == NULL) 581 return -EINVAL; 582 } 583 if (!(opt->opt_nflen|opt->opt_flen)) 584 opt = NULL; 585 } 586 587 if (!opt) { 588 opt = txopt_get(np); 589 opt_to_free = opt; 590 } 591 if (flowlabel) 592 opt = fl6_merge_options(&opt_space, flowlabel, opt); 593 opt = ipv6_fixup_options(&opt_space, opt); 594 ipc6.opt = opt; 595 596 fl6.flowi6_proto = sk->sk_protocol; 597 if (!ipv6_addr_any(daddr)) 598 fl6.daddr = *daddr; 599 else 600 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ 601 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr)) 602 fl6.saddr = np->saddr; 603 604 final_p = fl6_update_dst(&fl6, opt, &final); 605 606 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 607 fl6.flowi6_oif = np->mcast_oif; 608 else if (!fl6.flowi6_oif) 609 fl6.flowi6_oif = np->ucast_oif; 610 611 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6)); 612 613 if (ipc6.tclass < 0) 614 ipc6.tclass = np->tclass; 615 616 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); 617 618 dst = ip6_dst_lookup_flow(sk, &fl6, final_p); 619 if (IS_ERR(dst)) { 620 err = PTR_ERR(dst); 621 goto out; 622 } 623 624 if (ipc6.hlimit < 0) 625 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 626 627 if (ipc6.dontfrag < 0) 628 ipc6.dontfrag = np->dontfrag; 629 630 if (msg->msg_flags & MSG_CONFIRM) 631 goto do_confirm; 632 633 back_from_confirm: 634 lock_sock(sk); 635 err = ip6_append_data(sk, ip_generic_getfrag, msg, 636 ulen, transhdrlen, &ipc6, 637 &fl6, (struct rt6_info *)dst, 638 msg->msg_flags, &sockc_unused); 639 if (err) 640 ip6_flush_pending_frames(sk); 641 else if (!(msg->msg_flags & MSG_MORE)) 642 err = l2tp_ip6_push_pending_frames(sk); 643 release_sock(sk); 644 done: 645 dst_release(dst); 646 out: 647 fl6_sock_release(flowlabel); 648 txopt_put(opt_to_free); 649 650 return err < 0 ? err : len; 651 652 do_confirm: 653 dst_confirm(dst); 654 if (!(msg->msg_flags & MSG_PROBE) || len) 655 goto back_from_confirm; 656 err = 0; 657 goto done; 658 } 659 660 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 661 int noblock, int flags, int *addr_len) 662 { 663 struct ipv6_pinfo *np = inet6_sk(sk); 664 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 665 size_t copied = 0; 666 int err = -EOPNOTSUPP; 667 struct sk_buff *skb; 668 669 if (flags & MSG_OOB) 670 goto out; 671 672 if (addr_len) 673 *addr_len = sizeof(*lsa); 674 675 if (flags & MSG_ERRQUEUE) 676 return ipv6_recv_error(sk, msg, len, addr_len); 677 678 skb = skb_recv_datagram(sk, flags, noblock, &err); 679 if (!skb) 680 goto out; 681 682 copied = skb->len; 683 if (len < copied) { 684 msg->msg_flags |= MSG_TRUNC; 685 copied = len; 686 } 687 688 err = skb_copy_datagram_msg(skb, 0, msg, copied); 689 if (err) 690 goto done; 691 692 sock_recv_timestamp(msg, sk, skb); 693 694 /* Copy the address. */ 695 if (lsa) { 696 lsa->l2tp_family = AF_INET6; 697 lsa->l2tp_unused = 0; 698 lsa->l2tp_addr = ipv6_hdr(skb)->saddr; 699 lsa->l2tp_flowinfo = 0; 700 lsa->l2tp_scope_id = 0; 701 lsa->l2tp_conn_id = 0; 702 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 703 lsa->l2tp_scope_id = inet6_iif(skb); 704 } 705 706 if (np->rxopt.all) 707 ip6_datagram_recv_ctl(sk, msg, skb); 708 709 if (flags & MSG_TRUNC) 710 copied = skb->len; 711 done: 712 skb_free_datagram(sk, skb); 713 out: 714 return err ? err : copied; 715 } 716 717 static struct proto l2tp_ip6_prot = { 718 .name = "L2TP/IPv6", 719 .owner = THIS_MODULE, 720 .init = l2tp_ip6_open, 721 .close = l2tp_ip6_close, 722 .bind = l2tp_ip6_bind, 723 .connect = l2tp_ip6_connect, 724 .disconnect = l2tp_ip6_disconnect, 725 .ioctl = udp_ioctl, 726 .destroy = l2tp_ip6_destroy_sock, 727 .setsockopt = ipv6_setsockopt, 728 .getsockopt = ipv6_getsockopt, 729 .sendmsg = l2tp_ip6_sendmsg, 730 .recvmsg = l2tp_ip6_recvmsg, 731 .backlog_rcv = l2tp_ip6_backlog_recv, 732 .hash = inet6_hash, 733 .unhash = inet_unhash, 734 .obj_size = sizeof(struct l2tp_ip6_sock), 735 #ifdef CONFIG_COMPAT 736 .compat_setsockopt = compat_ipv6_setsockopt, 737 .compat_getsockopt = compat_ipv6_getsockopt, 738 #endif 739 }; 740 741 static const struct proto_ops l2tp_ip6_ops = { 742 .family = PF_INET6, 743 .owner = THIS_MODULE, 744 .release = inet6_release, 745 .bind = inet6_bind, 746 .connect = inet_dgram_connect, 747 .socketpair = sock_no_socketpair, 748 .accept = sock_no_accept, 749 .getname = l2tp_ip6_getname, 750 .poll = datagram_poll, 751 .ioctl = inet6_ioctl, 752 .listen = sock_no_listen, 753 .shutdown = inet_shutdown, 754 .setsockopt = sock_common_setsockopt, 755 .getsockopt = sock_common_getsockopt, 756 .sendmsg = inet_sendmsg, 757 .recvmsg = sock_common_recvmsg, 758 .mmap = sock_no_mmap, 759 .sendpage = sock_no_sendpage, 760 #ifdef CONFIG_COMPAT 761 .compat_setsockopt = compat_sock_common_setsockopt, 762 .compat_getsockopt = compat_sock_common_getsockopt, 763 #endif 764 }; 765 766 static struct inet_protosw l2tp_ip6_protosw = { 767 .type = SOCK_DGRAM, 768 .protocol = IPPROTO_L2TP, 769 .prot = &l2tp_ip6_prot, 770 .ops = &l2tp_ip6_ops, 771 }; 772 773 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = { 774 .handler = l2tp_ip6_recv, 775 }; 776 777 static int __init l2tp_ip6_init(void) 778 { 779 int err; 780 781 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n"); 782 783 err = proto_register(&l2tp_ip6_prot, 1); 784 if (err != 0) 785 goto out; 786 787 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 788 if (err) 789 goto out1; 790 791 inet6_register_protosw(&l2tp_ip6_protosw); 792 return 0; 793 794 out1: 795 proto_unregister(&l2tp_ip6_prot); 796 out: 797 return err; 798 } 799 800 static void __exit l2tp_ip6_exit(void) 801 { 802 inet6_unregister_protosw(&l2tp_ip6_protosw); 803 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 804 proto_unregister(&l2tp_ip6_prot); 805 } 806 807 module_init(l2tp_ip6_init); 808 module_exit(l2tp_ip6_exit); 809 810 MODULE_LICENSE("GPL"); 811 MODULE_AUTHOR("Chris Elston <celston@katalix.com>"); 812 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6"); 813 MODULE_VERSION("1.0"); 814 815 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like 816 * enums 817 */ 818 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP); 819 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP); 820