1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* L2TPv3 IP encapsulation support for IPv6 3 * 4 * Copyright (c) 2012 Katalix Systems Ltd 5 */ 6 7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 8 9 #include <linux/icmp.h> 10 #include <linux/module.h> 11 #include <linux/skbuff.h> 12 #include <linux/random.h> 13 #include <linux/socket.h> 14 #include <linux/l2tp.h> 15 #include <linux/in.h> 16 #include <linux/in6.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 <net/transp_v6.h> 27 #include <net/addrconf.h> 28 #include <net/ip6_route.h> 29 30 #include "l2tp_core.h" 31 32 struct l2tp_ip6_sock { 33 /* inet_sock has to be the first member of l2tp_ip6_sock */ 34 struct inet_sock inet; 35 36 u32 conn_id; 37 u32 peer_conn_id; 38 39 /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see 40 * inet6_sk_generic 41 */ 42 struct ipv6_pinfo inet6; 43 }; 44 45 static DEFINE_RWLOCK(l2tp_ip6_lock); 46 static struct hlist_head l2tp_ip6_table; 47 static struct hlist_head l2tp_ip6_bind_table; 48 49 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk) 50 { 51 return (struct l2tp_ip6_sock *)sk; 52 } 53 54 static struct sock *__l2tp_ip6_bind_lookup(const struct net *net, 55 const struct in6_addr *laddr, 56 const struct in6_addr *raddr, 57 int dif, u32 tunnel_id) 58 { 59 struct sock *sk; 60 61 sk_for_each_bound(sk, &l2tp_ip6_bind_table) { 62 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk); 63 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr; 64 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk); 65 int bound_dev_if; 66 67 if (!net_eq(sock_net(sk), net)) 68 continue; 69 70 bound_dev_if = READ_ONCE(sk->sk_bound_dev_if); 71 if (bound_dev_if && dif && 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; 136 137 if (!pskb_may_pull(skb, 4)) 138 goto discard; 139 140 /* Point to L2TP header */ 141 optr = skb->data; 142 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 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) 165 goto discard_sess; 166 167 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len); 168 l2tp_session_dec_refcount(session); 169 170 return 0; 171 172 pass_up: 173 /* Get the tunnel_id from the L2TP header */ 174 if (!pskb_may_pull(skb, 12)) 175 goto discard; 176 177 if ((skb->data[0] & 0xc0) != 0xc0) 178 goto discard; 179 180 tunnel_id = ntohl(*(__be32 *)&skb->data[4]); 181 iph = ipv6_hdr(skb); 182 183 read_lock_bh(&l2tp_ip6_lock); 184 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr, 185 inet6_iif(skb), tunnel_id); 186 if (!sk) { 187 read_unlock_bh(&l2tp_ip6_lock); 188 goto discard; 189 } 190 sock_hold(sk); 191 read_unlock_bh(&l2tp_ip6_lock); 192 193 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 194 goto discard_put; 195 196 nf_reset_ct(skb); 197 198 return sk_receive_skb(sk, skb, 1); 199 200 discard_sess: 201 l2tp_session_dec_refcount(session); 202 goto discard; 203 204 discard_put: 205 sock_put(sk); 206 207 discard: 208 kfree_skb(skb); 209 return 0; 210 } 211 212 static int l2tp_ip6_hash(struct sock *sk) 213 { 214 if (sk_unhashed(sk)) { 215 write_lock_bh(&l2tp_ip6_lock); 216 sk_add_node(sk, &l2tp_ip6_table); 217 write_unlock_bh(&l2tp_ip6_lock); 218 } 219 return 0; 220 } 221 222 static void l2tp_ip6_unhash(struct sock *sk) 223 { 224 if (sk_unhashed(sk)) 225 return; 226 write_lock_bh(&l2tp_ip6_lock); 227 sk_del_node_init(sk); 228 write_unlock_bh(&l2tp_ip6_lock); 229 } 230 231 static int l2tp_ip6_open(struct sock *sk) 232 { 233 /* Prevent autobind. We don't have ports. */ 234 inet_sk(sk)->inet_num = IPPROTO_L2TP; 235 236 l2tp_ip6_hash(sk); 237 return 0; 238 } 239 240 static void l2tp_ip6_close(struct sock *sk, long timeout) 241 { 242 write_lock_bh(&l2tp_ip6_lock); 243 hlist_del_init(&sk->sk_bind_node); 244 sk_del_node_init(sk); 245 write_unlock_bh(&l2tp_ip6_lock); 246 247 sk_common_release(sk); 248 } 249 250 static void l2tp_ip6_destroy_sock(struct sock *sk) 251 { 252 struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk); 253 254 lock_sock(sk); 255 ip6_flush_pending_frames(sk); 256 release_sock(sk); 257 258 if (tunnel) 259 l2tp_tunnel_delete(tunnel); 260 261 inet6_destroy_sock(sk); 262 } 263 264 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 265 { 266 struct inet_sock *inet = inet_sk(sk); 267 struct ipv6_pinfo *np = inet6_sk(sk); 268 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *)uaddr; 269 struct net *net = sock_net(sk); 270 __be32 v4addr = 0; 271 int bound_dev_if; 272 int addr_type; 273 int err; 274 275 if (addr->l2tp_family != AF_INET6) 276 return -EINVAL; 277 if (addr_len < sizeof(*addr)) 278 return -EINVAL; 279 280 addr_type = ipv6_addr_type(&addr->l2tp_addr); 281 282 /* l2tp_ip6 sockets are IPv6 only */ 283 if (addr_type == IPV6_ADDR_MAPPED) 284 return -EADDRNOTAVAIL; 285 286 /* L2TP is point-point, not multicast */ 287 if (addr_type & IPV6_ADDR_MULTICAST) 288 return -EADDRNOTAVAIL; 289 290 lock_sock(sk); 291 292 err = -EINVAL; 293 if (!sock_flag(sk, SOCK_ZAPPED)) 294 goto out_unlock; 295 296 if (sk->sk_state != TCP_CLOSE) 297 goto out_unlock; 298 299 bound_dev_if = sk->sk_bound_dev_if; 300 301 /* Check if the address belongs to the host. */ 302 rcu_read_lock(); 303 if (addr_type != IPV6_ADDR_ANY) { 304 struct net_device *dev = NULL; 305 306 if (addr_type & IPV6_ADDR_LINKLOCAL) { 307 if (addr->l2tp_scope_id) 308 bound_dev_if = addr->l2tp_scope_id; 309 310 /* Binding to link-local address requires an 311 * interface. 312 */ 313 if (!bound_dev_if) 314 goto out_unlock_rcu; 315 316 err = -ENODEV; 317 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if); 318 if (!dev) 319 goto out_unlock_rcu; 320 } 321 322 /* ipv4 addr of the socket is invalid. Only the 323 * unspecified and mapped address have a v4 equivalent. 324 */ 325 v4addr = LOOPBACK4_IPV6; 326 err = -EADDRNOTAVAIL; 327 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0)) 328 goto out_unlock_rcu; 329 } 330 rcu_read_unlock(); 331 332 write_lock_bh(&l2tp_ip6_lock); 333 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if, 334 addr->l2tp_conn_id)) { 335 write_unlock_bh(&l2tp_ip6_lock); 336 err = -EADDRINUSE; 337 goto out_unlock; 338 } 339 340 inet->inet_saddr = v4addr; 341 inet->inet_rcv_saddr = v4addr; 342 sk->sk_bound_dev_if = bound_dev_if; 343 sk->sk_v6_rcv_saddr = addr->l2tp_addr; 344 np->saddr = addr->l2tp_addr; 345 346 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id; 347 348 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 349 sk_del_node_init(sk); 350 write_unlock_bh(&l2tp_ip6_lock); 351 352 sock_reset_flag(sk, SOCK_ZAPPED); 353 release_sock(sk); 354 return 0; 355 356 out_unlock_rcu: 357 rcu_read_unlock(); 358 out_unlock: 359 release_sock(sk); 360 361 return err; 362 } 363 364 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr, 365 int addr_len) 366 { 367 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; 368 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 369 struct in6_addr *daddr; 370 int addr_type; 371 int rc; 372 373 if (addr_len < sizeof(*lsa)) 374 return -EINVAL; 375 376 if (usin->sin6_family != AF_INET6) 377 return -EINVAL; 378 379 addr_type = ipv6_addr_type(&usin->sin6_addr); 380 if (addr_type & IPV6_ADDR_MULTICAST) 381 return -EINVAL; 382 383 if (addr_type & IPV6_ADDR_MAPPED) { 384 daddr = &usin->sin6_addr; 385 if (ipv4_is_multicast(daddr->s6_addr32[3])) 386 return -EINVAL; 387 } 388 389 lock_sock(sk); 390 391 /* Must bind first - autobinding does not work */ 392 if (sock_flag(sk, SOCK_ZAPPED)) { 393 rc = -EINVAL; 394 goto out_sk; 395 } 396 397 rc = __ip6_datagram_connect(sk, uaddr, addr_len); 398 if (rc < 0) 399 goto out_sk; 400 401 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 402 403 write_lock_bh(&l2tp_ip6_lock); 404 hlist_del_init(&sk->sk_bind_node); 405 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 406 write_unlock_bh(&l2tp_ip6_lock); 407 408 out_sk: 409 release_sock(sk); 410 411 return rc; 412 } 413 414 static int l2tp_ip6_disconnect(struct sock *sk, int flags) 415 { 416 if (sock_flag(sk, SOCK_ZAPPED)) 417 return 0; 418 419 return __udp_disconnect(sk, flags); 420 } 421 422 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr, 423 int peer) 424 { 425 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; 426 struct sock *sk = sock->sk; 427 struct ipv6_pinfo *np = inet6_sk(sk); 428 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk); 429 430 lsa->l2tp_family = AF_INET6; 431 lsa->l2tp_flowinfo = 0; 432 lsa->l2tp_scope_id = 0; 433 lsa->l2tp_unused = 0; 434 if (peer) { 435 if (!lsk->peer_conn_id) 436 return -ENOTCONN; 437 lsa->l2tp_conn_id = lsk->peer_conn_id; 438 lsa->l2tp_addr = sk->sk_v6_daddr; 439 if (np->sndflow) 440 lsa->l2tp_flowinfo = np->flow_label; 441 } else { 442 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 443 lsa->l2tp_addr = np->saddr; 444 else 445 lsa->l2tp_addr = sk->sk_v6_rcv_saddr; 446 447 lsa->l2tp_conn_id = lsk->conn_id; 448 } 449 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 450 lsa->l2tp_scope_id = READ_ONCE(sk->sk_bound_dev_if); 451 return sizeof(*lsa); 452 } 453 454 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb) 455 { 456 int rc; 457 458 /* Charge it to the socket, dropping if the queue is full. */ 459 rc = sock_queue_rcv_skb(sk, skb); 460 if (rc < 0) 461 goto drop; 462 463 return 0; 464 465 drop: 466 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); 467 kfree_skb(skb); 468 return -1; 469 } 470 471 static int l2tp_ip6_push_pending_frames(struct sock *sk) 472 { 473 struct sk_buff *skb; 474 __be32 *transhdr = NULL; 475 int err = 0; 476 477 skb = skb_peek(&sk->sk_write_queue); 478 if (!skb) 479 goto out; 480 481 transhdr = (__be32 *)skb_transport_header(skb); 482 *transhdr = 0; 483 484 err = ip6_push_pending_frames(sk); 485 486 out: 487 return err; 488 } 489 490 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 491 * control frames. 492 */ 493 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 494 { 495 struct ipv6_txoptions opt_space; 496 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 497 struct in6_addr *daddr, *final_p, final; 498 struct ipv6_pinfo *np = inet6_sk(sk); 499 struct ipv6_txoptions *opt_to_free = NULL; 500 struct ipv6_txoptions *opt = NULL; 501 struct ip6_flowlabel *flowlabel = NULL; 502 struct dst_entry *dst = NULL; 503 struct flowi6 fl6; 504 struct ipcm6_cookie ipc6; 505 int addr_len = msg->msg_namelen; 506 int transhdrlen = 4; /* zero session-id */ 507 int ulen; 508 int err; 509 510 /* Rough check on arithmetic overflow, 511 * better check is made in ip6_append_data(). 512 */ 513 if (len > INT_MAX - transhdrlen) 514 return -EMSGSIZE; 515 ulen = len + transhdrlen; 516 517 /* Mirror BSD error message compatibility */ 518 if (msg->msg_flags & MSG_OOB) 519 return -EOPNOTSUPP; 520 521 /* Get and verify the address */ 522 memset(&fl6, 0, sizeof(fl6)); 523 524 fl6.flowi6_mark = sk->sk_mark; 525 fl6.flowi6_uid = sk->sk_uid; 526 527 ipcm6_init(&ipc6); 528 529 if (lsa) { 530 if (addr_len < SIN6_LEN_RFC2133) 531 return -EINVAL; 532 533 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6) 534 return -EAFNOSUPPORT; 535 536 daddr = &lsa->l2tp_addr; 537 if (np->sndflow) { 538 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK; 539 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 540 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 541 if (IS_ERR(flowlabel)) 542 return -EINVAL; 543 } 544 } 545 546 /* Otherwise it will be difficult to maintain 547 * sk->sk_dst_cache. 548 */ 549 if (sk->sk_state == TCP_ESTABLISHED && 550 ipv6_addr_equal(daddr, &sk->sk_v6_daddr)) 551 daddr = &sk->sk_v6_daddr; 552 553 if (addr_len >= sizeof(struct sockaddr_in6) && 554 lsa->l2tp_scope_id && 555 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL) 556 fl6.flowi6_oif = lsa->l2tp_scope_id; 557 } else { 558 if (sk->sk_state != TCP_ESTABLISHED) 559 return -EDESTADDRREQ; 560 561 daddr = &sk->sk_v6_daddr; 562 fl6.flowlabel = np->flow_label; 563 } 564 565 if (fl6.flowi6_oif == 0) 566 fl6.flowi6_oif = READ_ONCE(sk->sk_bound_dev_if); 567 568 if (msg->msg_controllen) { 569 opt = &opt_space; 570 memset(opt, 0, sizeof(struct ipv6_txoptions)); 571 opt->tot_len = sizeof(struct ipv6_txoptions); 572 ipc6.opt = opt; 573 574 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6); 575 if (err < 0) { 576 fl6_sock_release(flowlabel); 577 return err; 578 } 579 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) { 580 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 581 if (IS_ERR(flowlabel)) 582 return -EINVAL; 583 } 584 if (!(opt->opt_nflen | opt->opt_flen)) 585 opt = NULL; 586 } 587 588 if (!opt) { 589 opt = txopt_get(np); 590 opt_to_free = opt; 591 } 592 if (flowlabel) 593 opt = fl6_merge_options(&opt_space, flowlabel, opt); 594 opt = ipv6_fixup_options(&opt_space, opt); 595 ipc6.opt = opt; 596 597 fl6.flowi6_proto = sk->sk_protocol; 598 if (!ipv6_addr_any(daddr)) 599 fl6.daddr = *daddr; 600 else 601 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ 602 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr)) 603 fl6.saddr = np->saddr; 604 605 final_p = fl6_update_dst(&fl6, opt, &final); 606 607 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 608 fl6.flowi6_oif = np->mcast_oif; 609 else if (!fl6.flowi6_oif) 610 fl6.flowi6_oif = np->ucast_oif; 611 612 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); 613 614 if (ipc6.tclass < 0) 615 ipc6.tclass = np->tclass; 616 617 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); 618 619 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 620 if (IS_ERR(dst)) { 621 err = PTR_ERR(dst); 622 goto out; 623 } 624 625 if (ipc6.hlimit < 0) 626 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 627 628 if (ipc6.dontfrag < 0) 629 ipc6.dontfrag = np->dontfrag; 630 631 if (msg->msg_flags & MSG_CONFIRM) 632 goto do_confirm; 633 634 back_from_confirm: 635 lock_sock(sk); 636 err = ip6_append_data(sk, ip_generic_getfrag, msg, 637 ulen, transhdrlen, &ipc6, 638 &fl6, (struct rt6_info *)dst, 639 msg->msg_flags); 640 if (err) 641 ip6_flush_pending_frames(sk); 642 else if (!(msg->msg_flags & MSG_MORE)) 643 err = l2tp_ip6_push_pending_frames(sk); 644 release_sock(sk); 645 done: 646 dst_release(dst); 647 out: 648 fl6_sock_release(flowlabel); 649 txopt_put(opt_to_free); 650 651 return err < 0 ? err : len; 652 653 do_confirm: 654 if (msg->msg_flags & MSG_PROBE) 655 dst_confirm_neigh(dst, &fl6.daddr); 656 if (!(msg->msg_flags & MSG_PROBE) || len) 657 goto back_from_confirm; 658 err = 0; 659 goto done; 660 } 661 662 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 663 int flags, int *addr_len) 664 { 665 struct ipv6_pinfo *np = inet6_sk(sk); 666 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 667 size_t copied = 0; 668 int err = -EOPNOTSUPP; 669 struct sk_buff *skb; 670 671 if (flags & MSG_OOB) 672 goto out; 673 674 if (flags & MSG_ERRQUEUE) 675 return ipv6_recv_error(sk, msg, len, addr_len); 676 677 skb = skb_recv_datagram(sk, flags, &err); 678 if (!skb) 679 goto out; 680 681 copied = skb->len; 682 if (len < copied) { 683 msg->msg_flags |= MSG_TRUNC; 684 copied = len; 685 } 686 687 err = skb_copy_datagram_msg(skb, 0, msg, copied); 688 if (err) 689 goto done; 690 691 sock_recv_timestamp(msg, sk, skb); 692 693 /* Copy the address. */ 694 if (lsa) { 695 lsa->l2tp_family = AF_INET6; 696 lsa->l2tp_unused = 0; 697 lsa->l2tp_addr = ipv6_hdr(skb)->saddr; 698 lsa->l2tp_flowinfo = 0; 699 lsa->l2tp_scope_id = 0; 700 lsa->l2tp_conn_id = 0; 701 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 702 lsa->l2tp_scope_id = inet6_iif(skb); 703 *addr_len = sizeof(*lsa); 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 = l2tp_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 = l2tp_ip6_hash, 733 .unhash = l2tp_ip6_unhash, 734 .obj_size = sizeof(struct l2tp_ip6_sock), 735 }; 736 737 static const struct proto_ops l2tp_ip6_ops = { 738 .family = PF_INET6, 739 .owner = THIS_MODULE, 740 .release = inet6_release, 741 .bind = inet6_bind, 742 .connect = inet_dgram_connect, 743 .socketpair = sock_no_socketpair, 744 .accept = sock_no_accept, 745 .getname = l2tp_ip6_getname, 746 .poll = datagram_poll, 747 .ioctl = inet6_ioctl, 748 .gettstamp = sock_gettstamp, 749 .listen = sock_no_listen, 750 .shutdown = inet_shutdown, 751 .setsockopt = sock_common_setsockopt, 752 .getsockopt = sock_common_getsockopt, 753 .sendmsg = inet_sendmsg, 754 .recvmsg = sock_common_recvmsg, 755 .mmap = sock_no_mmap, 756 .sendpage = sock_no_sendpage, 757 #ifdef CONFIG_COMPAT 758 .compat_ioctl = inet6_compat_ioctl, 759 #endif 760 }; 761 762 static struct inet_protosw l2tp_ip6_protosw = { 763 .type = SOCK_DGRAM, 764 .protocol = IPPROTO_L2TP, 765 .prot = &l2tp_ip6_prot, 766 .ops = &l2tp_ip6_ops, 767 }; 768 769 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = { 770 .handler = l2tp_ip6_recv, 771 }; 772 773 static int __init l2tp_ip6_init(void) 774 { 775 int err; 776 777 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n"); 778 779 err = proto_register(&l2tp_ip6_prot, 1); 780 if (err != 0) 781 goto out; 782 783 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 784 if (err) 785 goto out1; 786 787 inet6_register_protosw(&l2tp_ip6_protosw); 788 return 0; 789 790 out1: 791 proto_unregister(&l2tp_ip6_prot); 792 out: 793 return err; 794 } 795 796 static void __exit l2tp_ip6_exit(void) 797 { 798 inet6_unregister_protosw(&l2tp_ip6_protosw); 799 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 800 proto_unregister(&l2tp_ip6_prot); 801 } 802 803 module_init(l2tp_ip6_init); 804 module_exit(l2tp_ip6_exit); 805 806 MODULE_LICENSE("GPL"); 807 MODULE_AUTHOR("Chris Elston <celston@katalix.com>"); 808 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6"); 809 MODULE_VERSION("1.0"); 810 811 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like 812 * enums 813 */ 814 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP); 815 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP); 816