1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * L2TPv3 IP encapsulation support for IPv6 4 * 5 * Copyright (c) 2012 Katalix Systems Ltd 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 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 <linux/in6.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/inet6_hashtables.h> 25 #include <net/tcp_states.h> 26 #include <net/protocol.h> 27 #include <net/xfrm.h> 28 29 #include <net/transp_v6.h> 30 #include <net/addrconf.h> 31 #include <net/ip6_route.h> 32 33 #include "l2tp_core.h" 34 35 struct l2tp_ip6_sock { 36 /* inet_sock has to be the first member of l2tp_ip6_sock */ 37 struct inet_sock inet; 38 39 u32 conn_id; 40 u32 peer_conn_id; 41 42 /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see 43 inet6_sk_generic */ 44 struct ipv6_pinfo inet6; 45 }; 46 47 static DEFINE_RWLOCK(l2tp_ip6_lock); 48 static struct hlist_head l2tp_ip6_table; 49 static struct hlist_head l2tp_ip6_bind_table; 50 51 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk) 52 { 53 return (struct l2tp_ip6_sock *)sk; 54 } 55 56 static struct sock *__l2tp_ip6_bind_lookup(const struct net *net, 57 const struct in6_addr *laddr, 58 const struct in6_addr *raddr, 59 int dif, u32 tunnel_id) 60 { 61 struct sock *sk; 62 63 sk_for_each_bound(sk, &l2tp_ip6_bind_table) { 64 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk); 65 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr; 66 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk); 67 68 if (!net_eq(sock_net(sk), net)) 69 continue; 70 71 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif) 72 continue; 73 74 if (sk_laddr && !ipv6_addr_any(sk_laddr) && 75 !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr)) 76 continue; 77 78 if (!ipv6_addr_any(sk_raddr) && raddr && 79 !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr)) 80 continue; 81 82 if (l2tp->conn_id != tunnel_id) 83 continue; 84 85 goto found; 86 } 87 88 sk = NULL; 89 found: 90 return sk; 91 } 92 93 /* When processing receive frames, there are two cases to 94 * consider. Data frames consist of a non-zero session-id and an 95 * optional cookie. Control frames consist of a regular L2TP header 96 * preceded by 32-bits of zeros. 97 * 98 * L2TPv3 Session Header Over IP 99 * 100 * 0 1 2 3 101 * 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 1 102 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 103 * | Session ID | 104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 105 * | Cookie (optional, maximum 64 bits)... 106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 107 * | 108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 109 * 110 * L2TPv3 Control Message Header Over IP 111 * 112 * 0 1 2 3 113 * 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 1 114 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 115 * | (32 bits of zeros) | 116 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 117 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length | 118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 119 * | Control Connection ID | 120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 121 * | Ns | Nr | 122 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 123 * 124 * All control frames are passed to userspace. 125 */ 126 static int l2tp_ip6_recv(struct sk_buff *skb) 127 { 128 struct net *net = dev_net(skb->dev); 129 struct sock *sk; 130 u32 session_id; 131 u32 tunnel_id; 132 unsigned char *ptr, *optr; 133 struct l2tp_session *session; 134 struct l2tp_tunnel *tunnel = NULL; 135 struct ipv6hdr *iph; 136 int length; 137 138 if (!pskb_may_pull(skb, 4)) 139 goto discard; 140 141 /* Point to L2TP header */ 142 optr = ptr = skb->data; 143 session_id = ntohl(*((__be32 *) ptr)); 144 ptr += 4; 145 146 /* RFC3931: L2TP/IP packets have the first 4 bytes containing 147 * the session_id. If it is 0, the packet is a L2TP control 148 * frame and the session_id value can be discarded. 149 */ 150 if (session_id == 0) { 151 __skb_pull(skb, 4); 152 goto pass_up; 153 } 154 155 /* Ok, this is a data packet. Lookup the session. */ 156 session = l2tp_session_get(net, session_id); 157 if (!session) 158 goto discard; 159 160 tunnel = session->tunnel; 161 if (!tunnel) 162 goto discard_sess; 163 164 /* Trace packet contents, if enabled */ 165 if (tunnel->debug & L2TP_MSG_DATA) { 166 length = min(32u, skb->len); 167 if (!pskb_may_pull(skb, length)) 168 goto discard_sess; 169 170 /* Point to L2TP header */ 171 optr = ptr = skb->data; 172 ptr += 4; 173 pr_debug("%s: ip recv\n", tunnel->name); 174 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length); 175 } 176 177 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) 178 goto discard_sess; 179 180 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len); 181 l2tp_session_dec_refcount(session); 182 183 return 0; 184 185 pass_up: 186 /* Get the tunnel_id from the L2TP header */ 187 if (!pskb_may_pull(skb, 12)) 188 goto discard; 189 190 if ((skb->data[0] & 0xc0) != 0xc0) 191 goto discard; 192 193 tunnel_id = ntohl(*(__be32 *) &skb->data[4]); 194 iph = ipv6_hdr(skb); 195 196 read_lock_bh(&l2tp_ip6_lock); 197 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr, 198 inet6_iif(skb), tunnel_id); 199 if (!sk) { 200 read_unlock_bh(&l2tp_ip6_lock); 201 goto discard; 202 } 203 sock_hold(sk); 204 read_unlock_bh(&l2tp_ip6_lock); 205 206 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 207 goto discard_put; 208 209 nf_reset_ct(skb); 210 211 return sk_receive_skb(sk, skb, 1); 212 213 discard_sess: 214 l2tp_session_dec_refcount(session); 215 goto discard; 216 217 discard_put: 218 sock_put(sk); 219 220 discard: 221 kfree_skb(skb); 222 return 0; 223 } 224 225 static int l2tp_ip6_open(struct sock *sk) 226 { 227 /* Prevent autobind. We don't have ports. */ 228 inet_sk(sk)->inet_num = IPPROTO_L2TP; 229 230 write_lock_bh(&l2tp_ip6_lock); 231 sk_add_node(sk, &l2tp_ip6_table); 232 write_unlock_bh(&l2tp_ip6_lock); 233 234 return 0; 235 } 236 237 static void l2tp_ip6_close(struct sock *sk, long timeout) 238 { 239 write_lock_bh(&l2tp_ip6_lock); 240 hlist_del_init(&sk->sk_bind_node); 241 sk_del_node_init(sk); 242 write_unlock_bh(&l2tp_ip6_lock); 243 244 sk_common_release(sk); 245 } 246 247 static void l2tp_ip6_destroy_sock(struct sock *sk) 248 { 249 struct l2tp_tunnel *tunnel = sk->sk_user_data; 250 251 lock_sock(sk); 252 ip6_flush_pending_frames(sk); 253 release_sock(sk); 254 255 if (tunnel) 256 l2tp_tunnel_delete(tunnel); 257 258 inet6_destroy_sock(sk); 259 } 260 261 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 262 { 263 struct inet_sock *inet = inet_sk(sk); 264 struct ipv6_pinfo *np = inet6_sk(sk); 265 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr; 266 struct net *net = sock_net(sk); 267 __be32 v4addr = 0; 268 int bound_dev_if; 269 int addr_type; 270 int err; 271 272 if (addr->l2tp_family != AF_INET6) 273 return -EINVAL; 274 if (addr_len < sizeof(*addr)) 275 return -EINVAL; 276 277 addr_type = ipv6_addr_type(&addr->l2tp_addr); 278 279 /* l2tp_ip6 sockets are IPv6 only */ 280 if (addr_type == IPV6_ADDR_MAPPED) 281 return -EADDRNOTAVAIL; 282 283 /* L2TP is point-point, not multicast */ 284 if (addr_type & IPV6_ADDR_MULTICAST) 285 return -EADDRNOTAVAIL; 286 287 lock_sock(sk); 288 289 err = -EINVAL; 290 if (!sock_flag(sk, SOCK_ZAPPED)) 291 goto out_unlock; 292 293 if (sk->sk_state != TCP_CLOSE) 294 goto out_unlock; 295 296 bound_dev_if = sk->sk_bound_dev_if; 297 298 /* Check if the address belongs to the host. */ 299 rcu_read_lock(); 300 if (addr_type != IPV6_ADDR_ANY) { 301 struct net_device *dev = NULL; 302 303 if (addr_type & IPV6_ADDR_LINKLOCAL) { 304 if (addr->l2tp_scope_id) 305 bound_dev_if = addr->l2tp_scope_id; 306 307 /* Binding to link-local address requires an 308 * interface. 309 */ 310 if (!bound_dev_if) 311 goto out_unlock_rcu; 312 313 err = -ENODEV; 314 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if); 315 if (!dev) 316 goto out_unlock_rcu; 317 } 318 319 /* ipv4 addr of the socket is invalid. Only the 320 * unspecified and mapped address have a v4 equivalent. 321 */ 322 v4addr = LOOPBACK4_IPV6; 323 err = -EADDRNOTAVAIL; 324 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0)) 325 goto out_unlock_rcu; 326 } 327 rcu_read_unlock(); 328 329 write_lock_bh(&l2tp_ip6_lock); 330 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if, 331 addr->l2tp_conn_id)) { 332 write_unlock_bh(&l2tp_ip6_lock); 333 err = -EADDRINUSE; 334 goto out_unlock; 335 } 336 337 inet->inet_saddr = v4addr; 338 inet->inet_rcv_saddr = v4addr; 339 sk->sk_bound_dev_if = bound_dev_if; 340 sk->sk_v6_rcv_saddr = addr->l2tp_addr; 341 np->saddr = addr->l2tp_addr; 342 343 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id; 344 345 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 346 sk_del_node_init(sk); 347 write_unlock_bh(&l2tp_ip6_lock); 348 349 sock_reset_flag(sk, SOCK_ZAPPED); 350 release_sock(sk); 351 return 0; 352 353 out_unlock_rcu: 354 rcu_read_unlock(); 355 out_unlock: 356 release_sock(sk); 357 358 return err; 359 } 360 361 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr, 362 int addr_len) 363 { 364 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr; 365 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr; 366 struct in6_addr *daddr; 367 int addr_type; 368 int rc; 369 370 if (addr_len < sizeof(*lsa)) 371 return -EINVAL; 372 373 if (usin->sin6_family != AF_INET6) 374 return -EINVAL; 375 376 addr_type = ipv6_addr_type(&usin->sin6_addr); 377 if (addr_type & IPV6_ADDR_MULTICAST) 378 return -EINVAL; 379 380 if (addr_type & IPV6_ADDR_MAPPED) { 381 daddr = &usin->sin6_addr; 382 if (ipv4_is_multicast(daddr->s6_addr32[3])) 383 return -EINVAL; 384 } 385 386 lock_sock(sk); 387 388 /* Must bind first - autobinding does not work */ 389 if (sock_flag(sk, SOCK_ZAPPED)) { 390 rc = -EINVAL; 391 goto out_sk; 392 } 393 394 rc = __ip6_datagram_connect(sk, uaddr, addr_len); 395 if (rc < 0) 396 goto out_sk; 397 398 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 399 400 write_lock_bh(&l2tp_ip6_lock); 401 hlist_del_init(&sk->sk_bind_node); 402 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 403 write_unlock_bh(&l2tp_ip6_lock); 404 405 out_sk: 406 release_sock(sk); 407 408 return rc; 409 } 410 411 static int l2tp_ip6_disconnect(struct sock *sk, int flags) 412 { 413 if (sock_flag(sk, SOCK_ZAPPED)) 414 return 0; 415 416 return __udp_disconnect(sk, flags); 417 } 418 419 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr, 420 int peer) 421 { 422 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; 423 struct sock *sk = sock->sk; 424 struct ipv6_pinfo *np = inet6_sk(sk); 425 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk); 426 427 lsa->l2tp_family = AF_INET6; 428 lsa->l2tp_flowinfo = 0; 429 lsa->l2tp_scope_id = 0; 430 lsa->l2tp_unused = 0; 431 if (peer) { 432 if (!lsk->peer_conn_id) 433 return -ENOTCONN; 434 lsa->l2tp_conn_id = lsk->peer_conn_id; 435 lsa->l2tp_addr = sk->sk_v6_daddr; 436 if (np->sndflow) 437 lsa->l2tp_flowinfo = np->flow_label; 438 } else { 439 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 440 lsa->l2tp_addr = np->saddr; 441 else 442 lsa->l2tp_addr = sk->sk_v6_rcv_saddr; 443 444 lsa->l2tp_conn_id = lsk->conn_id; 445 } 446 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 447 lsa->l2tp_scope_id = sk->sk_bound_dev_if; 448 return sizeof(*lsa); 449 } 450 451 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb) 452 { 453 int rc; 454 455 /* Charge it to the socket, dropping if the queue is full. */ 456 rc = sock_queue_rcv_skb(sk, skb); 457 if (rc < 0) 458 goto drop; 459 460 return 0; 461 462 drop: 463 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); 464 kfree_skb(skb); 465 return -1; 466 } 467 468 static int l2tp_ip6_push_pending_frames(struct sock *sk) 469 { 470 struct sk_buff *skb; 471 __be32 *transhdr = NULL; 472 int err = 0; 473 474 skb = skb_peek(&sk->sk_write_queue); 475 if (skb == NULL) 476 goto out; 477 478 transhdr = (__be32 *)skb_transport_header(skb); 479 *transhdr = 0; 480 481 err = ip6_push_pending_frames(sk); 482 483 out: 484 return err; 485 } 486 487 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 488 * control frames. 489 */ 490 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 491 { 492 struct ipv6_txoptions opt_space; 493 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 494 struct in6_addr *daddr, *final_p, final; 495 struct ipv6_pinfo *np = inet6_sk(sk); 496 struct ipv6_txoptions *opt_to_free = NULL; 497 struct ipv6_txoptions *opt = NULL; 498 struct ip6_flowlabel *flowlabel = NULL; 499 struct dst_entry *dst = NULL; 500 struct flowi6 fl6; 501 struct ipcm6_cookie ipc6; 502 int addr_len = msg->msg_namelen; 503 int transhdrlen = 4; /* zero session-id */ 504 int ulen = len + transhdrlen; 505 int err; 506 507 /* Rough check on arithmetic overflow, 508 better check is made in ip6_append_data(). 509 */ 510 if (len > INT_MAX) 511 return -EMSGSIZE; 512 513 /* Mirror BSD error message compatibility */ 514 if (msg->msg_flags & MSG_OOB) 515 return -EOPNOTSUPP; 516 517 /* 518 * Get and verify the address. 519 */ 520 memset(&fl6, 0, sizeof(fl6)); 521 522 fl6.flowi6_mark = sk->sk_mark; 523 fl6.flowi6_uid = sk->sk_uid; 524 525 ipcm6_init(&ipc6); 526 527 if (lsa) { 528 if (addr_len < SIN6_LEN_RFC2133) 529 return -EINVAL; 530 531 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6) 532 return -EAFNOSUPPORT; 533 534 daddr = &lsa->l2tp_addr; 535 if (np->sndflow) { 536 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK; 537 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) { 538 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 539 if (IS_ERR(flowlabel)) 540 return -EINVAL; 541 } 542 } 543 544 /* 545 * Otherwise it will be difficult to maintain 546 * sk->sk_dst_cache. 547 */ 548 if (sk->sk_state == TCP_ESTABLISHED && 549 ipv6_addr_equal(daddr, &sk->sk_v6_daddr)) 550 daddr = &sk->sk_v6_daddr; 551 552 if (addr_len >= sizeof(struct sockaddr_in6) && 553 lsa->l2tp_scope_id && 554 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL) 555 fl6.flowi6_oif = lsa->l2tp_scope_id; 556 } else { 557 if (sk->sk_state != TCP_ESTABLISHED) 558 return -EDESTADDRREQ; 559 560 daddr = &sk->sk_v6_daddr; 561 fl6.flowlabel = np->flow_label; 562 } 563 564 if (fl6.flowi6_oif == 0) 565 fl6.flowi6_oif = sk->sk_bound_dev_if; 566 567 if (msg->msg_controllen) { 568 opt = &opt_space; 569 memset(opt, 0, sizeof(struct ipv6_txoptions)); 570 opt->tot_len = sizeof(struct ipv6_txoptions); 571 ipc6.opt = opt; 572 573 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6); 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 (IS_ERR(flowlabel)) 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(sock_net(sk), 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); 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 if (msg->msg_flags & MSG_PROBE) 654 dst_confirm_neigh(dst, &fl6.daddr); 655 if (!(msg->msg_flags & MSG_PROBE) || len) 656 goto back_from_confirm; 657 err = 0; 658 goto done; 659 } 660 661 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 662 int noblock, int flags, int *addr_len) 663 { 664 struct ipv6_pinfo *np = inet6_sk(sk); 665 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 666 size_t copied = 0; 667 int err = -EOPNOTSUPP; 668 struct sk_buff *skb; 669 670 if (flags & MSG_OOB) 671 goto out; 672 673 if (flags & MSG_ERRQUEUE) 674 return ipv6_recv_error(sk, msg, len, addr_len); 675 676 skb = skb_recv_datagram(sk, flags, noblock, &err); 677 if (!skb) 678 goto out; 679 680 copied = skb->len; 681 if (len < copied) { 682 msg->msg_flags |= MSG_TRUNC; 683 copied = len; 684 } 685 686 err = skb_copy_datagram_msg(skb, 0, msg, copied); 687 if (err) 688 goto done; 689 690 sock_recv_timestamp(msg, sk, skb); 691 692 /* Copy the address. */ 693 if (lsa) { 694 lsa->l2tp_family = AF_INET6; 695 lsa->l2tp_unused = 0; 696 lsa->l2tp_addr = ipv6_hdr(skb)->saddr; 697 lsa->l2tp_flowinfo = 0; 698 lsa->l2tp_scope_id = 0; 699 lsa->l2tp_conn_id = 0; 700 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 701 lsa->l2tp_scope_id = inet6_iif(skb); 702 *addr_len = sizeof(*lsa); 703 } 704 705 if (np->rxopt.all) 706 ip6_datagram_recv_ctl(sk, msg, skb); 707 708 if (flags & MSG_TRUNC) 709 copied = skb->len; 710 done: 711 skb_free_datagram(sk, skb); 712 out: 713 return err ? err : copied; 714 } 715 716 static struct proto l2tp_ip6_prot = { 717 .name = "L2TP/IPv6", 718 .owner = THIS_MODULE, 719 .init = l2tp_ip6_open, 720 .close = l2tp_ip6_close, 721 .bind = l2tp_ip6_bind, 722 .connect = l2tp_ip6_connect, 723 .disconnect = l2tp_ip6_disconnect, 724 .ioctl = l2tp_ioctl, 725 .destroy = l2tp_ip6_destroy_sock, 726 .setsockopt = ipv6_setsockopt, 727 .getsockopt = ipv6_getsockopt, 728 .sendmsg = l2tp_ip6_sendmsg, 729 .recvmsg = l2tp_ip6_recvmsg, 730 .backlog_rcv = l2tp_ip6_backlog_recv, 731 .hash = inet6_hash, 732 .unhash = inet_unhash, 733 .obj_size = sizeof(struct l2tp_ip6_sock), 734 #ifdef CONFIG_COMPAT 735 .compat_setsockopt = compat_ipv6_setsockopt, 736 .compat_getsockopt = compat_ipv6_getsockopt, 737 #endif 738 }; 739 740 static const struct proto_ops l2tp_ip6_ops = { 741 .family = PF_INET6, 742 .owner = THIS_MODULE, 743 .release = inet6_release, 744 .bind = inet6_bind, 745 .connect = inet_dgram_connect, 746 .socketpair = sock_no_socketpair, 747 .accept = sock_no_accept, 748 .getname = l2tp_ip6_getname, 749 .poll = datagram_poll, 750 .ioctl = inet6_ioctl, 751 .gettstamp = sock_gettstamp, 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