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 struct ipv6_pinfo inet6; 40 }; 41 42 static DEFINE_RWLOCK(l2tp_ip6_lock); 43 static struct hlist_head l2tp_ip6_table; 44 static struct hlist_head l2tp_ip6_bind_table; 45 46 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk) 47 { 48 return (struct l2tp_ip6_sock *)sk; 49 } 50 51 static struct sock *__l2tp_ip6_bind_lookup(const struct net *net, 52 const struct in6_addr *laddr, 53 const struct in6_addr *raddr, 54 int dif, u32 tunnel_id) 55 { 56 struct sock *sk; 57 58 sk_for_each_bound(sk, &l2tp_ip6_bind_table) { 59 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk); 60 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr; 61 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk); 62 int bound_dev_if; 63 64 if (!net_eq(sock_net(sk), net)) 65 continue; 66 67 bound_dev_if = READ_ONCE(sk->sk_bound_dev_if); 68 if (bound_dev_if && dif && bound_dev_if != dif) 69 continue; 70 71 if (sk_laddr && !ipv6_addr_any(sk_laddr) && 72 !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr)) 73 continue; 74 75 if (!ipv6_addr_any(sk_raddr) && raddr && 76 !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr)) 77 continue; 78 79 if (l2tp->conn_id != tunnel_id) 80 continue; 81 82 goto found; 83 } 84 85 sk = NULL; 86 found: 87 return sk; 88 } 89 90 /* When processing receive frames, there are two cases to 91 * consider. Data frames consist of a non-zero session-id and an 92 * optional cookie. Control frames consist of a regular L2TP header 93 * preceded by 32-bits of zeros. 94 * 95 * L2TPv3 Session Header Over IP 96 * 97 * 0 1 2 3 98 * 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 99 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 100 * | Session ID | 101 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 102 * | Cookie (optional, maximum 64 bits)... 103 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 104 * | 105 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 106 * 107 * L2TPv3 Control Message Header Over IP 108 * 109 * 0 1 2 3 110 * 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 1 111 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 112 * | (32 bits of zeros) | 113 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 114 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length | 115 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 116 * | Control Connection ID | 117 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 118 * | Ns | Nr | 119 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 120 * 121 * All control frames are passed to userspace. 122 */ 123 static int l2tp_ip6_recv(struct sk_buff *skb) 124 { 125 struct net *net = dev_net(skb->dev); 126 struct sock *sk; 127 u32 session_id; 128 u32 tunnel_id; 129 unsigned char *ptr, *optr; 130 struct l2tp_session *session; 131 struct l2tp_tunnel *tunnel = NULL; 132 struct ipv6hdr *iph; 133 134 if (!pskb_may_pull(skb, 4)) 135 goto discard; 136 137 /* Point to L2TP header */ 138 optr = skb->data; 139 ptr = skb->data; 140 session_id = ntohl(*((__be32 *)ptr)); 141 ptr += 4; 142 143 /* RFC3931: L2TP/IP packets have the first 4 bytes containing 144 * the session_id. If it is 0, the packet is a L2TP control 145 * frame and the session_id value can be discarded. 146 */ 147 if (session_id == 0) { 148 __skb_pull(skb, 4); 149 goto pass_up; 150 } 151 152 /* Ok, this is a data packet. Lookup the session. */ 153 session = l2tp_v3_session_get(net, NULL, session_id); 154 if (!session) 155 goto discard; 156 157 tunnel = session->tunnel; 158 if (!tunnel) 159 goto discard_sess; 160 161 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) 162 goto discard_sess; 163 164 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len); 165 l2tp_session_dec_refcount(session); 166 167 return 0; 168 169 pass_up: 170 /* Get the tunnel_id from the L2TP header */ 171 if (!pskb_may_pull(skb, 12)) 172 goto discard; 173 174 if ((skb->data[0] & 0xc0) != 0xc0) 175 goto discard; 176 177 tunnel_id = ntohl(*(__be32 *)&skb->data[4]); 178 iph = ipv6_hdr(skb); 179 180 read_lock_bh(&l2tp_ip6_lock); 181 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr, 182 inet6_iif(skb), tunnel_id); 183 if (!sk) { 184 read_unlock_bh(&l2tp_ip6_lock); 185 goto discard; 186 } 187 sock_hold(sk); 188 read_unlock_bh(&l2tp_ip6_lock); 189 190 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 191 goto discard_put; 192 193 nf_reset_ct(skb); 194 195 return sk_receive_skb(sk, skb, 1); 196 197 discard_sess: 198 l2tp_session_dec_refcount(session); 199 goto discard; 200 201 discard_put: 202 sock_put(sk); 203 204 discard: 205 kfree_skb(skb); 206 return 0; 207 } 208 209 static int l2tp_ip6_hash(struct sock *sk) 210 { 211 if (sk_unhashed(sk)) { 212 write_lock_bh(&l2tp_ip6_lock); 213 sk_add_node(sk, &l2tp_ip6_table); 214 write_unlock_bh(&l2tp_ip6_lock); 215 } 216 return 0; 217 } 218 219 static void l2tp_ip6_unhash(struct sock *sk) 220 { 221 if (sk_unhashed(sk)) 222 return; 223 write_lock_bh(&l2tp_ip6_lock); 224 sk_del_node_init(sk); 225 write_unlock_bh(&l2tp_ip6_lock); 226 } 227 228 static int l2tp_ip6_open(struct sock *sk) 229 { 230 /* Prevent autobind. We don't have ports. */ 231 inet_sk(sk)->inet_num = IPPROTO_L2TP; 232 233 l2tp_ip6_hash(sk); 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 = l2tp_sk_to_tunnel(sk); 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 } 258 259 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) 260 { 261 struct inet_sock *inet = inet_sk(sk); 262 struct ipv6_pinfo *np = inet6_sk(sk); 263 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *)uaddr; 264 struct net *net = sock_net(sk); 265 __be32 v4addr = 0; 266 int bound_dev_if; 267 int addr_type; 268 int err; 269 270 if (addr->l2tp_family != AF_INET6) 271 return -EINVAL; 272 if (addr_len < sizeof(*addr)) 273 return -EINVAL; 274 275 addr_type = ipv6_addr_type(&addr->l2tp_addr); 276 277 /* l2tp_ip6 sockets are IPv6 only */ 278 if (addr_type == IPV6_ADDR_MAPPED) 279 return -EADDRNOTAVAIL; 280 281 /* L2TP is point-point, not multicast */ 282 if (addr_type & IPV6_ADDR_MULTICAST) 283 return -EADDRNOTAVAIL; 284 285 lock_sock(sk); 286 287 err = -EINVAL; 288 if (!sock_flag(sk, SOCK_ZAPPED)) 289 goto out_unlock; 290 291 if (sk->sk_state != TCP_CLOSE) 292 goto out_unlock; 293 294 bound_dev_if = sk->sk_bound_dev_if; 295 296 /* Check if the address belongs to the host. */ 297 rcu_read_lock(); 298 if (addr_type != IPV6_ADDR_ANY) { 299 struct net_device *dev = NULL; 300 301 if (addr_type & IPV6_ADDR_LINKLOCAL) { 302 if (addr->l2tp_scope_id) 303 bound_dev_if = addr->l2tp_scope_id; 304 305 /* Binding to link-local address requires an 306 * interface. 307 */ 308 if (!bound_dev_if) 309 goto out_unlock_rcu; 310 311 err = -ENODEV; 312 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if); 313 if (!dev) 314 goto out_unlock_rcu; 315 } 316 317 /* ipv4 addr of the socket is invalid. Only the 318 * unspecified and mapped address have a v4 equivalent. 319 */ 320 v4addr = LOOPBACK4_IPV6; 321 err = -EADDRNOTAVAIL; 322 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0)) 323 goto out_unlock_rcu; 324 } 325 rcu_read_unlock(); 326 327 write_lock_bh(&l2tp_ip6_lock); 328 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if, 329 addr->l2tp_conn_id)) { 330 write_unlock_bh(&l2tp_ip6_lock); 331 err = -EADDRINUSE; 332 goto out_unlock; 333 } 334 335 inet->inet_saddr = v4addr; 336 inet->inet_rcv_saddr = v4addr; 337 sk->sk_bound_dev_if = bound_dev_if; 338 sk->sk_v6_rcv_saddr = addr->l2tp_addr; 339 np->saddr = addr->l2tp_addr; 340 341 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id; 342 343 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 344 sk_del_node_init(sk); 345 write_unlock_bh(&l2tp_ip6_lock); 346 347 sock_reset_flag(sk, SOCK_ZAPPED); 348 release_sock(sk); 349 return 0; 350 351 out_unlock_rcu: 352 rcu_read_unlock(); 353 out_unlock: 354 release_sock(sk); 355 356 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 (addr_len < sizeof(*lsa)) 369 return -EINVAL; 370 371 if (usin->sin6_family != AF_INET6) 372 return -EINVAL; 373 374 addr_type = ipv6_addr_type(&usin->sin6_addr); 375 if (addr_type & IPV6_ADDR_MULTICAST) 376 return -EINVAL; 377 378 if (addr_type & IPV6_ADDR_MAPPED) { 379 daddr = &usin->sin6_addr; 380 if (ipv4_is_multicast(daddr->s6_addr32[3])) 381 return -EINVAL; 382 } 383 384 lock_sock(sk); 385 386 /* Must bind first - autobinding does not work */ 387 if (sock_flag(sk, SOCK_ZAPPED)) { 388 rc = -EINVAL; 389 goto out_sk; 390 } 391 392 rc = __ip6_datagram_connect(sk, uaddr, addr_len); 393 if (rc < 0) 394 goto out_sk; 395 396 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 397 398 write_lock_bh(&l2tp_ip6_lock); 399 hlist_del_init(&sk->sk_bind_node); 400 sk_add_bind_node(sk, &l2tp_ip6_bind_table); 401 write_unlock_bh(&l2tp_ip6_lock); 402 403 out_sk: 404 release_sock(sk); 405 406 return rc; 407 } 408 409 static int l2tp_ip6_disconnect(struct sock *sk, int flags) 410 { 411 if (sock_flag(sk, SOCK_ZAPPED)) 412 return 0; 413 414 return __udp_disconnect(sk, flags); 415 } 416 417 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr, 418 int peer) 419 { 420 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; 421 struct sock *sk = sock->sk; 422 struct ipv6_pinfo *np = inet6_sk(sk); 423 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk); 424 425 lsa->l2tp_family = AF_INET6; 426 lsa->l2tp_flowinfo = 0; 427 lsa->l2tp_scope_id = 0; 428 lsa->l2tp_unused = 0; 429 if (peer) { 430 if (!lsk->peer_conn_id) 431 return -ENOTCONN; 432 lsa->l2tp_conn_id = lsk->peer_conn_id; 433 lsa->l2tp_addr = sk->sk_v6_daddr; 434 if (inet6_test_bit(SNDFLOW, sk)) 435 lsa->l2tp_flowinfo = np->flow_label; 436 } else { 437 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 438 lsa->l2tp_addr = np->saddr; 439 else 440 lsa->l2tp_addr = sk->sk_v6_rcv_saddr; 441 442 lsa->l2tp_conn_id = lsk->conn_id; 443 } 444 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 445 lsa->l2tp_scope_id = READ_ONCE(sk->sk_bound_dev_if); 446 return sizeof(*lsa); 447 } 448 449 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb) 450 { 451 int rc; 452 453 /* Charge it to the socket, dropping if the queue is full. */ 454 rc = sock_queue_rcv_skb(sk, skb); 455 if (rc < 0) 456 goto drop; 457 458 return 0; 459 460 drop: 461 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); 462 kfree_skb(skb); 463 return -1; 464 } 465 466 static int l2tp_ip6_push_pending_frames(struct sock *sk) 467 { 468 struct sk_buff *skb; 469 __be32 *transhdr = NULL; 470 int err = 0; 471 472 skb = skb_peek(&sk->sk_write_queue); 473 if (!skb) 474 goto out; 475 476 transhdr = (__be32 *)skb_transport_header(skb); 477 *transhdr = 0; 478 479 err = ip6_push_pending_frames(sk); 480 481 out: 482 return err; 483 } 484 485 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 486 * control frames. 487 */ 488 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 489 { 490 struct ipv6_txoptions opt_space; 491 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 492 struct in6_addr *daddr, *final_p, final; 493 struct ipv6_pinfo *np = inet6_sk(sk); 494 struct ipv6_txoptions *opt_to_free = NULL; 495 struct ipv6_txoptions *opt = NULL; 496 struct ip6_flowlabel *flowlabel = NULL; 497 struct dst_entry *dst = NULL; 498 struct flowi6 fl6; 499 struct ipcm6_cookie ipc6; 500 int addr_len = msg->msg_namelen; 501 int transhdrlen = 4; /* zero session-id */ 502 int ulen; 503 int err; 504 505 /* Rough check on arithmetic overflow, 506 * better check is made in ip6_append_data(). 507 */ 508 if (len > INT_MAX - transhdrlen) 509 return -EMSGSIZE; 510 511 /* Mirror BSD error message compatibility */ 512 if (msg->msg_flags & MSG_OOB) 513 return -EOPNOTSUPP; 514 515 /* Get and verify the address */ 516 memset(&fl6, 0, sizeof(fl6)); 517 518 fl6.flowi6_mark = READ_ONCE(sk->sk_mark); 519 fl6.flowi6_uid = sk->sk_uid; 520 521 ipcm6_init(&ipc6); 522 523 if (lsa) { 524 if (addr_len < SIN6_LEN_RFC2133) 525 return -EINVAL; 526 527 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6) 528 return -EAFNOSUPPORT; 529 530 daddr = &lsa->l2tp_addr; 531 if (inet6_test_bit(SNDFLOW, sk)) { 532 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK; 533 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 534 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 535 if (IS_ERR(flowlabel)) 536 return -EINVAL; 537 } 538 } 539 540 /* Otherwise it will be difficult to maintain 541 * sk->sk_dst_cache. 542 */ 543 if (sk->sk_state == TCP_ESTABLISHED && 544 ipv6_addr_equal(daddr, &sk->sk_v6_daddr)) 545 daddr = &sk->sk_v6_daddr; 546 547 if (addr_len >= sizeof(struct sockaddr_in6) && 548 lsa->l2tp_scope_id && 549 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL) 550 fl6.flowi6_oif = lsa->l2tp_scope_id; 551 } else { 552 if (sk->sk_state != TCP_ESTABLISHED) 553 return -EDESTADDRREQ; 554 555 daddr = &sk->sk_v6_daddr; 556 fl6.flowlabel = np->flow_label; 557 } 558 559 if (fl6.flowi6_oif == 0) 560 fl6.flowi6_oif = READ_ONCE(sk->sk_bound_dev_if); 561 562 if (msg->msg_controllen) { 563 opt = &opt_space; 564 memset(opt, 0, sizeof(struct ipv6_txoptions)); 565 opt->tot_len = sizeof(struct ipv6_txoptions); 566 ipc6.opt = opt; 567 568 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6); 569 if (err < 0) { 570 fl6_sock_release(flowlabel); 571 return err; 572 } 573 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) { 574 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 575 if (IS_ERR(flowlabel)) 576 return -EINVAL; 577 } 578 if (!(opt->opt_nflen | opt->opt_flen)) 579 opt = NULL; 580 } 581 582 if (!opt) { 583 opt = txopt_get(np); 584 opt_to_free = opt; 585 } 586 if (flowlabel) 587 opt = fl6_merge_options(&opt_space, flowlabel, opt); 588 opt = ipv6_fixup_options(&opt_space, opt); 589 ipc6.opt = opt; 590 591 fl6.flowi6_proto = sk->sk_protocol; 592 if (!ipv6_addr_any(daddr)) 593 fl6.daddr = *daddr; 594 else 595 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ 596 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr)) 597 fl6.saddr = np->saddr; 598 599 final_p = fl6_update_dst(&fl6, opt, &final); 600 601 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 602 fl6.flowi6_oif = READ_ONCE(np->mcast_oif); 603 else if (!fl6.flowi6_oif) 604 fl6.flowi6_oif = READ_ONCE(np->ucast_oif); 605 606 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); 607 608 if (ipc6.tclass < 0) 609 ipc6.tclass = np->tclass; 610 611 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); 612 613 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 614 if (IS_ERR(dst)) { 615 err = PTR_ERR(dst); 616 goto out; 617 } 618 619 if (ipc6.hlimit < 0) 620 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 621 622 if (ipc6.dontfrag < 0) 623 ipc6.dontfrag = inet6_test_bit(DONTFRAG, sk); 624 625 if (msg->msg_flags & MSG_CONFIRM) 626 goto do_confirm; 627 628 back_from_confirm: 629 lock_sock(sk); 630 ulen = len + (skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0); 631 err = ip6_append_data(sk, ip_generic_getfrag, msg, 632 ulen, transhdrlen, &ipc6, 633 &fl6, dst_rt6_info(dst), 634 msg->msg_flags); 635 if (err) 636 ip6_flush_pending_frames(sk); 637 else if (!(msg->msg_flags & MSG_MORE)) 638 err = l2tp_ip6_push_pending_frames(sk); 639 release_sock(sk); 640 done: 641 dst_release(dst); 642 out: 643 fl6_sock_release(flowlabel); 644 txopt_put(opt_to_free); 645 646 return err < 0 ? err : len; 647 648 do_confirm: 649 if (msg->msg_flags & MSG_PROBE) 650 dst_confirm_neigh(dst, &fl6.daddr); 651 if (!(msg->msg_flags & MSG_PROBE) || len) 652 goto back_from_confirm; 653 err = 0; 654 goto done; 655 } 656 657 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 658 int flags, int *addr_len) 659 { 660 struct ipv6_pinfo *np = inet6_sk(sk); 661 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 662 size_t copied = 0; 663 int err = -EOPNOTSUPP; 664 struct sk_buff *skb; 665 666 if (flags & MSG_OOB) 667 goto out; 668 669 if (flags & MSG_ERRQUEUE) 670 return ipv6_recv_error(sk, msg, len, addr_len); 671 672 skb = skb_recv_datagram(sk, flags, &err); 673 if (!skb) 674 goto out; 675 676 copied = skb->len; 677 if (len < copied) { 678 msg->msg_flags |= MSG_TRUNC; 679 copied = len; 680 } 681 682 err = skb_copy_datagram_msg(skb, 0, msg, copied); 683 if (err) 684 goto done; 685 686 sock_recv_timestamp(msg, sk, skb); 687 688 /* Copy the address. */ 689 if (lsa) { 690 lsa->l2tp_family = AF_INET6; 691 lsa->l2tp_unused = 0; 692 lsa->l2tp_addr = ipv6_hdr(skb)->saddr; 693 lsa->l2tp_flowinfo = 0; 694 lsa->l2tp_scope_id = 0; 695 lsa->l2tp_conn_id = 0; 696 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 697 lsa->l2tp_scope_id = inet6_iif(skb); 698 *addr_len = sizeof(*lsa); 699 } 700 701 if (np->rxopt.all) 702 ip6_datagram_recv_ctl(sk, msg, skb); 703 704 if (flags & MSG_TRUNC) 705 copied = skb->len; 706 done: 707 skb_free_datagram(sk, skb); 708 out: 709 return err ? err : copied; 710 } 711 712 static struct proto l2tp_ip6_prot = { 713 .name = "L2TP/IPv6", 714 .owner = THIS_MODULE, 715 .init = l2tp_ip6_open, 716 .close = l2tp_ip6_close, 717 .bind = l2tp_ip6_bind, 718 .connect = l2tp_ip6_connect, 719 .disconnect = l2tp_ip6_disconnect, 720 .ioctl = l2tp_ioctl, 721 .destroy = l2tp_ip6_destroy_sock, 722 .setsockopt = ipv6_setsockopt, 723 .getsockopt = ipv6_getsockopt, 724 .sendmsg = l2tp_ip6_sendmsg, 725 .recvmsg = l2tp_ip6_recvmsg, 726 .backlog_rcv = l2tp_ip6_backlog_recv, 727 .hash = l2tp_ip6_hash, 728 .unhash = l2tp_ip6_unhash, 729 .obj_size = sizeof(struct l2tp_ip6_sock), 730 .ipv6_pinfo_offset = offsetof(struct l2tp_ip6_sock, inet6), 731 }; 732 733 static const struct proto_ops l2tp_ip6_ops = { 734 .family = PF_INET6, 735 .owner = THIS_MODULE, 736 .release = inet6_release, 737 .bind = inet6_bind, 738 .connect = inet_dgram_connect, 739 .socketpair = sock_no_socketpair, 740 .accept = sock_no_accept, 741 .getname = l2tp_ip6_getname, 742 .poll = datagram_poll, 743 .ioctl = inet6_ioctl, 744 .gettstamp = sock_gettstamp, 745 .listen = sock_no_listen, 746 .shutdown = inet_shutdown, 747 .setsockopt = sock_common_setsockopt, 748 .getsockopt = sock_common_getsockopt, 749 .sendmsg = inet_sendmsg, 750 .recvmsg = sock_common_recvmsg, 751 .mmap = sock_no_mmap, 752 #ifdef CONFIG_COMPAT 753 .compat_ioctl = inet6_compat_ioctl, 754 #endif 755 }; 756 757 static struct inet_protosw l2tp_ip6_protosw = { 758 .type = SOCK_DGRAM, 759 .protocol = IPPROTO_L2TP, 760 .prot = &l2tp_ip6_prot, 761 .ops = &l2tp_ip6_ops, 762 }; 763 764 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = { 765 .handler = l2tp_ip6_recv, 766 }; 767 768 static int __init l2tp_ip6_init(void) 769 { 770 int err; 771 772 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n"); 773 774 err = proto_register(&l2tp_ip6_prot, 1); 775 if (err != 0) 776 goto out; 777 778 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 779 if (err) 780 goto out1; 781 782 inet6_register_protosw(&l2tp_ip6_protosw); 783 return 0; 784 785 out1: 786 proto_unregister(&l2tp_ip6_prot); 787 out: 788 return err; 789 } 790 791 static void __exit l2tp_ip6_exit(void) 792 { 793 inet6_unregister_protosw(&l2tp_ip6_protosw); 794 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 795 proto_unregister(&l2tp_ip6_prot); 796 } 797 798 module_init(l2tp_ip6_init); 799 module_exit(l2tp_ip6_exit); 800 801 MODULE_LICENSE("GPL"); 802 MODULE_AUTHOR("Chris Elston <celston@katalix.com>"); 803 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6"); 804 MODULE_VERSION("1.0"); 805 806 /* Use the values of SOCK_DGRAM (2) as type and IPPROTO_L2TP (115) as protocol, 807 * because __stringify doesn't like enums 808 */ 809 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 115, 2); 810 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, 115); 811