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 } 261 262 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 263 { 264 struct inet_sock *inet = inet_sk(sk); 265 struct ipv6_pinfo *np = inet6_sk(sk); 266 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *)uaddr; 267 struct net *net = sock_net(sk); 268 __be32 v4addr = 0; 269 int bound_dev_if; 270 int addr_type; 271 int err; 272 273 if (addr->l2tp_family != AF_INET6) 274 return -EINVAL; 275 if (addr_len < sizeof(*addr)) 276 return -EINVAL; 277 278 addr_type = ipv6_addr_type(&addr->l2tp_addr); 279 280 /* l2tp_ip6 sockets are IPv6 only */ 281 if (addr_type == IPV6_ADDR_MAPPED) 282 return -EADDRNOTAVAIL; 283 284 /* L2TP is point-point, not multicast */ 285 if (addr_type & IPV6_ADDR_MULTICAST) 286 return -EADDRNOTAVAIL; 287 288 lock_sock(sk); 289 290 err = -EINVAL; 291 if (!sock_flag(sk, SOCK_ZAPPED)) 292 goto out_unlock; 293 294 if (sk->sk_state != TCP_CLOSE) 295 goto out_unlock; 296 297 bound_dev_if = sk->sk_bound_dev_if; 298 299 /* Check if the address belongs to the host. */ 300 rcu_read_lock(); 301 if (addr_type != IPV6_ADDR_ANY) { 302 struct net_device *dev = NULL; 303 304 if (addr_type & IPV6_ADDR_LINKLOCAL) { 305 if (addr->l2tp_scope_id) 306 bound_dev_if = addr->l2tp_scope_id; 307 308 /* Binding to link-local address requires an 309 * interface. 310 */ 311 if (!bound_dev_if) 312 goto out_unlock_rcu; 313 314 err = -ENODEV; 315 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if); 316 if (!dev) 317 goto out_unlock_rcu; 318 } 319 320 /* ipv4 addr of the socket is invalid. Only the 321 * unspecified and mapped address have a v4 equivalent. 322 */ 323 v4addr = LOOPBACK4_IPV6; 324 err = -EADDRNOTAVAIL; 325 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0)) 326 goto out_unlock_rcu; 327 } 328 rcu_read_unlock(); 329 330 write_lock_bh(&l2tp_ip6_lock); 331 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if, 332 addr->l2tp_conn_id)) { 333 write_unlock_bh(&l2tp_ip6_lock); 334 err = -EADDRINUSE; 335 goto out_unlock; 336 } 337 338 inet->inet_saddr = v4addr; 339 inet->inet_rcv_saddr = v4addr; 340 sk->sk_bound_dev_if = bound_dev_if; 341 sk->sk_v6_rcv_saddr = addr->l2tp_addr; 342 np->saddr = addr->l2tp_addr; 343 344 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id; 345 346 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 347 sk_del_node_init(sk); 348 write_unlock_bh(&l2tp_ip6_lock); 349 350 sock_reset_flag(sk, SOCK_ZAPPED); 351 release_sock(sk); 352 return 0; 353 354 out_unlock_rcu: 355 rcu_read_unlock(); 356 out_unlock: 357 release_sock(sk); 358 359 return err; 360 } 361 362 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr, 363 int addr_len) 364 { 365 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; 366 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 367 struct in6_addr *daddr; 368 int addr_type; 369 int rc; 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 lock_sock(sk); 388 389 /* Must bind first - autobinding does not work */ 390 if (sock_flag(sk, SOCK_ZAPPED)) { 391 rc = -EINVAL; 392 goto out_sk; 393 } 394 395 rc = __ip6_datagram_connect(sk, uaddr, addr_len); 396 if (rc < 0) 397 goto out_sk; 398 399 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 400 401 write_lock_bh(&l2tp_ip6_lock); 402 hlist_del_init(&sk->sk_bind_node); 403 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 404 write_unlock_bh(&l2tp_ip6_lock); 405 406 out_sk: 407 release_sock(sk); 408 409 return rc; 410 } 411 412 static int l2tp_ip6_disconnect(struct sock *sk, int flags) 413 { 414 if (sock_flag(sk, SOCK_ZAPPED)) 415 return 0; 416 417 return __udp_disconnect(sk, flags); 418 } 419 420 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr, 421 int peer) 422 { 423 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; 424 struct sock *sk = sock->sk; 425 struct ipv6_pinfo *np = inet6_sk(sk); 426 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk); 427 428 lsa->l2tp_family = AF_INET6; 429 lsa->l2tp_flowinfo = 0; 430 lsa->l2tp_scope_id = 0; 431 lsa->l2tp_unused = 0; 432 if (peer) { 433 if (!lsk->peer_conn_id) 434 return -ENOTCONN; 435 lsa->l2tp_conn_id = lsk->peer_conn_id; 436 lsa->l2tp_addr = sk->sk_v6_daddr; 437 if (np->sndflow) 438 lsa->l2tp_flowinfo = np->flow_label; 439 } else { 440 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 441 lsa->l2tp_addr = np->saddr; 442 else 443 lsa->l2tp_addr = sk->sk_v6_rcv_saddr; 444 445 lsa->l2tp_conn_id = lsk->conn_id; 446 } 447 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 448 lsa->l2tp_scope_id = READ_ONCE(sk->sk_bound_dev_if); 449 return sizeof(*lsa); 450 } 451 452 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb) 453 { 454 int rc; 455 456 /* Charge it to the socket, dropping if the queue is full. */ 457 rc = sock_queue_rcv_skb(sk, skb); 458 if (rc < 0) 459 goto drop; 460 461 return 0; 462 463 drop: 464 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); 465 kfree_skb(skb); 466 return -1; 467 } 468 469 static int l2tp_ip6_push_pending_frames(struct sock *sk) 470 { 471 struct sk_buff *skb; 472 __be32 *transhdr = NULL; 473 int err = 0; 474 475 skb = skb_peek(&sk->sk_write_queue); 476 if (!skb) 477 goto out; 478 479 transhdr = (__be32 *)skb_transport_header(skb); 480 *transhdr = 0; 481 482 err = ip6_push_pending_frames(sk); 483 484 out: 485 return err; 486 } 487 488 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 489 * control frames. 490 */ 491 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 492 { 493 struct ipv6_txoptions opt_space; 494 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 495 struct in6_addr *daddr, *final_p, final; 496 struct ipv6_pinfo *np = inet6_sk(sk); 497 struct ipv6_txoptions *opt_to_free = NULL; 498 struct ipv6_txoptions *opt = NULL; 499 struct ip6_flowlabel *flowlabel = NULL; 500 struct dst_entry *dst = NULL; 501 struct flowi6 fl6; 502 struct ipcm6_cookie ipc6; 503 int addr_len = msg->msg_namelen; 504 int transhdrlen = 4; /* zero session-id */ 505 int ulen; 506 int err; 507 508 /* Rough check on arithmetic overflow, 509 * better check is made in ip6_append_data(). 510 */ 511 if (len > INT_MAX - transhdrlen) 512 return -EMSGSIZE; 513 ulen = len + transhdrlen; 514 515 /* Mirror BSD error message compatibility */ 516 if (msg->msg_flags & MSG_OOB) 517 return -EOPNOTSUPP; 518 519 /* Get and verify the address */ 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 /* 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 = READ_ONCE(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 if (err < 0) { 574 fl6_sock_release(flowlabel); 575 return err; 576 } 577 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) { 578 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 579 if (IS_ERR(flowlabel)) 580 return -EINVAL; 581 } 582 if (!(opt->opt_nflen | opt->opt_flen)) 583 opt = NULL; 584 } 585 586 if (!opt) { 587 opt = txopt_get(np); 588 opt_to_free = opt; 589 } 590 if (flowlabel) 591 opt = fl6_merge_options(&opt_space, flowlabel, opt); 592 opt = ipv6_fixup_options(&opt_space, opt); 593 ipc6.opt = opt; 594 595 fl6.flowi6_proto = sk->sk_protocol; 596 if (!ipv6_addr_any(daddr)) 597 fl6.daddr = *daddr; 598 else 599 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ 600 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr)) 601 fl6.saddr = np->saddr; 602 603 final_p = fl6_update_dst(&fl6, opt, &final); 604 605 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 606 fl6.flowi6_oif = np->mcast_oif; 607 else if (!fl6.flowi6_oif) 608 fl6.flowi6_oif = np->ucast_oif; 609 610 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); 611 612 if (ipc6.tclass < 0) 613 ipc6.tclass = np->tclass; 614 615 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); 616 617 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 618 if (IS_ERR(dst)) { 619 err = PTR_ERR(dst); 620 goto out; 621 } 622 623 if (ipc6.hlimit < 0) 624 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 625 626 if (ipc6.dontfrag < 0) 627 ipc6.dontfrag = np->dontfrag; 628 629 if (msg->msg_flags & MSG_CONFIRM) 630 goto do_confirm; 631 632 back_from_confirm: 633 lock_sock(sk); 634 err = ip6_append_data(sk, ip_generic_getfrag, msg, 635 ulen, transhdrlen, &ipc6, 636 &fl6, (struct rt6_info *)dst, 637 msg->msg_flags); 638 if (err) 639 ip6_flush_pending_frames(sk); 640 else if (!(msg->msg_flags & MSG_MORE)) 641 err = l2tp_ip6_push_pending_frames(sk); 642 release_sock(sk); 643 done: 644 dst_release(dst); 645 out: 646 fl6_sock_release(flowlabel); 647 txopt_put(opt_to_free); 648 649 return err < 0 ? err : len; 650 651 do_confirm: 652 if (msg->msg_flags & MSG_PROBE) 653 dst_confirm_neigh(dst, &fl6.daddr); 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 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 (flags & MSG_ERRQUEUE) 673 return ipv6_recv_error(sk, msg, len, addr_len); 674 675 skb = skb_recv_datagram(sk, flags, &err); 676 if (!skb) 677 goto out; 678 679 copied = skb->len; 680 if (len < copied) { 681 msg->msg_flags |= MSG_TRUNC; 682 copied = len; 683 } 684 685 err = skb_copy_datagram_msg(skb, 0, msg, copied); 686 if (err) 687 goto done; 688 689 sock_recv_timestamp(msg, sk, skb); 690 691 /* Copy the address. */ 692 if (lsa) { 693 lsa->l2tp_family = AF_INET6; 694 lsa->l2tp_unused = 0; 695 lsa->l2tp_addr = ipv6_hdr(skb)->saddr; 696 lsa->l2tp_flowinfo = 0; 697 lsa->l2tp_scope_id = 0; 698 lsa->l2tp_conn_id = 0; 699 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 700 lsa->l2tp_scope_id = inet6_iif(skb); 701 *addr_len = sizeof(*lsa); 702 } 703 704 if (np->rxopt.all) 705 ip6_datagram_recv_ctl(sk, msg, skb); 706 707 if (flags & MSG_TRUNC) 708 copied = skb->len; 709 done: 710 skb_free_datagram(sk, skb); 711 out: 712 return err ? err : copied; 713 } 714 715 static struct proto l2tp_ip6_prot = { 716 .name = "L2TP/IPv6", 717 .owner = THIS_MODULE, 718 .init = l2tp_ip6_open, 719 .close = l2tp_ip6_close, 720 .bind = l2tp_ip6_bind, 721 .connect = l2tp_ip6_connect, 722 .disconnect = l2tp_ip6_disconnect, 723 .ioctl = l2tp_ioctl, 724 .destroy = l2tp_ip6_destroy_sock, 725 .setsockopt = ipv6_setsockopt, 726 .getsockopt = ipv6_getsockopt, 727 .sendmsg = l2tp_ip6_sendmsg, 728 .recvmsg = l2tp_ip6_recvmsg, 729 .backlog_rcv = l2tp_ip6_backlog_recv, 730 .hash = l2tp_ip6_hash, 731 .unhash = l2tp_ip6_unhash, 732 .obj_size = sizeof(struct l2tp_ip6_sock), 733 }; 734 735 static const struct proto_ops l2tp_ip6_ops = { 736 .family = PF_INET6, 737 .owner = THIS_MODULE, 738 .release = inet6_release, 739 .bind = inet6_bind, 740 .connect = inet_dgram_connect, 741 .socketpair = sock_no_socketpair, 742 .accept = sock_no_accept, 743 .getname = l2tp_ip6_getname, 744 .poll = datagram_poll, 745 .ioctl = inet6_ioctl, 746 .gettstamp = sock_gettstamp, 747 .listen = sock_no_listen, 748 .shutdown = inet_shutdown, 749 .setsockopt = sock_common_setsockopt, 750 .getsockopt = sock_common_getsockopt, 751 .sendmsg = inet_sendmsg, 752 .recvmsg = sock_common_recvmsg, 753 .mmap = sock_no_mmap, 754 .sendpage = sock_no_sendpage, 755 #ifdef CONFIG_COMPAT 756 .compat_ioctl = inet6_compat_ioctl, 757 #endif 758 }; 759 760 static struct inet_protosw l2tp_ip6_protosw = { 761 .type = SOCK_DGRAM, 762 .protocol = IPPROTO_L2TP, 763 .prot = &l2tp_ip6_prot, 764 .ops = &l2tp_ip6_ops, 765 }; 766 767 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = { 768 .handler = l2tp_ip6_recv, 769 }; 770 771 static int __init l2tp_ip6_init(void) 772 { 773 int err; 774 775 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n"); 776 777 err = proto_register(&l2tp_ip6_prot, 1); 778 if (err != 0) 779 goto out; 780 781 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 782 if (err) 783 goto out1; 784 785 inet6_register_protosw(&l2tp_ip6_protosw); 786 return 0; 787 788 out1: 789 proto_unregister(&l2tp_ip6_prot); 790 out: 791 return err; 792 } 793 794 static void __exit l2tp_ip6_exit(void) 795 { 796 inet6_unregister_protosw(&l2tp_ip6_protosw); 797 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 798 proto_unregister(&l2tp_ip6_prot); 799 } 800 801 module_init(l2tp_ip6_init); 802 module_exit(l2tp_ip6_exit); 803 804 MODULE_LICENSE("GPL"); 805 MODULE_AUTHOR("Chris Elston <celston@katalix.com>"); 806 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6"); 807 MODULE_VERSION("1.0"); 808 809 /* Use the values of SOCK_DGRAM (2) as type and IPPROTO_L2TP (115) as protocol, 810 * because __stringify doesn't like enums 811 */ 812 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 115, 2); 813 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, 115); 814