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 #include <net/net_namespace.h> 26 #include <net/netns/generic.h> 27 28 #include <net/transp_v6.h> 29 #include <net/addrconf.h> 30 #include <net/ip6_route.h> 31 32 #include "l2tp_core.h" 33 34 /* per-net private data for this module */ 35 static unsigned int l2tp_ip6_net_id; 36 struct l2tp_ip6_net { 37 rwlock_t l2tp_ip6_lock; 38 struct hlist_head l2tp_ip6_table; 39 struct hlist_head l2tp_ip6_bind_table; 40 }; 41 42 struct l2tp_ip6_sock { 43 /* inet_sock has to be the first member of l2tp_ip6_sock */ 44 struct inet_sock inet; 45 46 u32 conn_id; 47 u32 peer_conn_id; 48 49 struct ipv6_pinfo inet6; 50 }; 51 52 static struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk) 53 { 54 return (struct l2tp_ip6_sock *)sk; 55 } 56 57 static struct l2tp_ip6_net *l2tp_ip6_pernet(const struct net *net) 58 { 59 return net_generic(net, l2tp_ip6_net_id); 60 } 61 62 static struct sock *__l2tp_ip6_bind_lookup(const struct net *net, 63 const struct in6_addr *laddr, 64 const struct in6_addr *raddr, 65 int dif, u32 tunnel_id) 66 { 67 struct l2tp_ip6_net *pn = l2tp_ip6_pernet(net); 68 struct sock *sk; 69 70 sk_for_each_bound(sk, &pn->l2tp_ip6_bind_table) { 71 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk); 72 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr; 73 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk); 74 int bound_dev_if; 75 76 if (!net_eq(sock_net(sk), net)) 77 continue; 78 79 bound_dev_if = READ_ONCE(sk->sk_bound_dev_if); 80 if (bound_dev_if && dif && bound_dev_if != dif) 81 continue; 82 83 if (sk_laddr && !ipv6_addr_any(sk_laddr) && 84 !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr)) 85 continue; 86 87 if (!ipv6_addr_any(sk_raddr) && raddr && 88 !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr)) 89 continue; 90 91 if (l2tp->conn_id != tunnel_id) 92 continue; 93 94 goto found; 95 } 96 97 sk = NULL; 98 found: 99 return sk; 100 } 101 102 /* When processing receive frames, there are two cases to 103 * consider. Data frames consist of a non-zero session-id and an 104 * optional cookie. Control frames consist of a regular L2TP header 105 * preceded by 32-bits of zeros. 106 * 107 * L2TPv3 Session 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 * | Session ID | 113 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 114 * | Cookie (optional, maximum 64 bits)... 115 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 116 * | 117 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 118 * 119 * L2TPv3 Control Message Header Over IP 120 * 121 * 0 1 2 3 122 * 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 1 123 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 124 * | (32 bits of zeros) | 125 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 126 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length | 127 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 128 * | Control Connection ID | 129 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 130 * | Ns | Nr | 131 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 * 133 * All control frames are passed to userspace. 134 */ 135 static int l2tp_ip6_recv(struct sk_buff *skb) 136 { 137 struct net *net = dev_net(skb->dev); 138 struct l2tp_ip6_net *pn; 139 struct sock *sk; 140 u32 session_id; 141 u32 tunnel_id; 142 unsigned char *ptr, *optr; 143 struct l2tp_session *session; 144 struct l2tp_tunnel *tunnel = NULL; 145 struct ipv6hdr *iph; 146 147 pn = l2tp_ip6_pernet(net); 148 149 if (!pskb_may_pull(skb, 4)) 150 goto discard; 151 152 /* Point to L2TP header */ 153 optr = skb->data; 154 ptr = skb->data; 155 session_id = ntohl(*((__be32 *)ptr)); 156 ptr += 4; 157 158 /* RFC3931: L2TP/IP packets have the first 4 bytes containing 159 * the session_id. If it is 0, the packet is a L2TP control 160 * frame and the session_id value can be discarded. 161 */ 162 if (session_id == 0) { 163 __skb_pull(skb, 4); 164 goto pass_up; 165 } 166 167 /* Ok, this is a data packet. Lookup the session. */ 168 session = l2tp_v3_session_get(net, NULL, session_id); 169 if (!session) 170 goto discard; 171 172 tunnel = session->tunnel; 173 if (!tunnel) 174 goto discard_sess; 175 176 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) 177 goto discard_sess; 178 179 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len); 180 l2tp_session_put(session); 181 182 return 0; 183 184 pass_up: 185 /* Get the tunnel_id from the L2TP header */ 186 if (!pskb_may_pull(skb, 12)) 187 goto discard; 188 189 if ((skb->data[0] & 0xc0) != 0xc0) 190 goto discard; 191 192 tunnel_id = ntohl(*(__be32 *)&skb->data[4]); 193 iph = ipv6_hdr(skb); 194 195 read_lock_bh(&pn->l2tp_ip6_lock); 196 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr, 197 inet6_iif(skb), tunnel_id); 198 if (!sk) { 199 read_unlock_bh(&pn->l2tp_ip6_lock); 200 goto discard; 201 } 202 sock_hold(sk); 203 read_unlock_bh(&pn->l2tp_ip6_lock); 204 205 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) 206 goto discard_put; 207 208 nf_reset_ct(skb); 209 210 return sk_receive_skb(sk, skb, 1); 211 212 discard_sess: 213 l2tp_session_put(session); 214 goto discard; 215 216 discard_put: 217 sock_put(sk); 218 219 discard: 220 kfree_skb(skb); 221 return 0; 222 } 223 224 static int l2tp_ip6_hash(struct sock *sk) 225 { 226 struct l2tp_ip6_net *pn = l2tp_ip6_pernet(sock_net(sk)); 227 228 if (sk_unhashed(sk)) { 229 write_lock_bh(&pn->l2tp_ip6_lock); 230 sk_add_node(sk, &pn->l2tp_ip6_table); 231 write_unlock_bh(&pn->l2tp_ip6_lock); 232 } 233 return 0; 234 } 235 236 static void l2tp_ip6_unhash(struct sock *sk) 237 { 238 struct l2tp_ip6_net *pn = l2tp_ip6_pernet(sock_net(sk)); 239 240 if (sk_unhashed(sk)) 241 return; 242 write_lock_bh(&pn->l2tp_ip6_lock); 243 sk_del_node_init(sk); 244 write_unlock_bh(&pn->l2tp_ip6_lock); 245 } 246 247 static int l2tp_ip6_open(struct sock *sk) 248 { 249 /* Prevent autobind. We don't have ports. */ 250 inet_sk(sk)->inet_num = IPPROTO_L2TP; 251 252 l2tp_ip6_hash(sk); 253 return 0; 254 } 255 256 static void l2tp_ip6_close(struct sock *sk, long timeout) 257 { 258 struct l2tp_ip6_net *pn = l2tp_ip6_pernet(sock_net(sk)); 259 260 write_lock_bh(&pn->l2tp_ip6_lock); 261 hlist_del_init(&sk->sk_bind_node); 262 sk_del_node_init(sk); 263 write_unlock_bh(&pn->l2tp_ip6_lock); 264 265 sk_common_release(sk); 266 } 267 268 static void l2tp_ip6_destroy_sock(struct sock *sk) 269 { 270 struct l2tp_tunnel *tunnel; 271 272 lock_sock(sk); 273 ip6_flush_pending_frames(sk); 274 release_sock(sk); 275 276 tunnel = l2tp_sk_to_tunnel(sk); 277 if (tunnel) { 278 l2tp_tunnel_delete(tunnel); 279 l2tp_tunnel_put(tunnel); 280 } 281 } 282 283 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr_unsized *uaddr, 284 int addr_len) 285 { 286 struct inet_sock *inet = inet_sk(sk); 287 struct ipv6_pinfo *np = inet6_sk(sk); 288 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *)uaddr; 289 struct net *net = sock_net(sk); 290 struct l2tp_ip6_net *pn; 291 __be32 v4addr = 0; 292 int bound_dev_if; 293 int addr_type; 294 int err; 295 296 pn = l2tp_ip6_pernet(net); 297 298 if (addr->l2tp_family != AF_INET6) 299 return -EINVAL; 300 if (addr_len < sizeof(*addr)) 301 return -EINVAL; 302 303 addr_type = ipv6_addr_type(&addr->l2tp_addr); 304 305 /* l2tp_ip6 sockets are IPv6 only */ 306 if (addr_type == IPV6_ADDR_MAPPED) 307 return -EADDRNOTAVAIL; 308 309 /* L2TP is point-point, not multicast */ 310 if (addr_type & IPV6_ADDR_MULTICAST) 311 return -EADDRNOTAVAIL; 312 313 lock_sock(sk); 314 315 err = -EINVAL; 316 if (!sock_flag(sk, SOCK_ZAPPED)) 317 goto out_unlock; 318 319 if (sk->sk_state != TCP_CLOSE) 320 goto out_unlock; 321 322 bound_dev_if = sk->sk_bound_dev_if; 323 324 /* Check if the address belongs to the host. */ 325 rcu_read_lock(); 326 if (addr_type != IPV6_ADDR_ANY) { 327 struct net_device *dev = NULL; 328 329 if (addr_type & IPV6_ADDR_LINKLOCAL) { 330 if (addr->l2tp_scope_id) 331 bound_dev_if = addr->l2tp_scope_id; 332 333 /* Binding to link-local address requires an 334 * interface. 335 */ 336 if (!bound_dev_if) 337 goto out_unlock_rcu; 338 339 err = -ENODEV; 340 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if); 341 if (!dev) 342 goto out_unlock_rcu; 343 } 344 345 /* ipv4 addr of the socket is invalid. Only the 346 * unspecified and mapped address have a v4 equivalent. 347 */ 348 v4addr = LOOPBACK4_IPV6; 349 err = -EADDRNOTAVAIL; 350 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0)) 351 goto out_unlock_rcu; 352 } 353 rcu_read_unlock(); 354 355 write_lock_bh(&pn->l2tp_ip6_lock); 356 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if, 357 addr->l2tp_conn_id)) { 358 write_unlock_bh(&pn->l2tp_ip6_lock); 359 err = -EADDRINUSE; 360 goto out_unlock; 361 } 362 363 inet->inet_saddr = v4addr; 364 inet->inet_rcv_saddr = v4addr; 365 sk->sk_bound_dev_if = bound_dev_if; 366 sk->sk_v6_rcv_saddr = addr->l2tp_addr; 367 np->saddr = addr->l2tp_addr; 368 369 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id; 370 371 sk_add_bind_node(sk, &pn->l2tp_ip6_bind_table); 372 sk_del_node_init(sk); 373 write_unlock_bh(&pn->l2tp_ip6_lock); 374 375 sock_reset_flag(sk, SOCK_ZAPPED); 376 release_sock(sk); 377 return 0; 378 379 out_unlock_rcu: 380 rcu_read_unlock(); 381 out_unlock: 382 release_sock(sk); 383 384 return err; 385 } 386 387 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr_unsized *uaddr, 388 int addr_len) 389 { 390 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; 391 struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; 392 struct in6_addr *daddr; 393 int addr_type; 394 int rc; 395 struct l2tp_ip6_net *pn; 396 397 if (addr_len < sizeof(*lsa)) 398 return -EINVAL; 399 400 if (usin->sin6_family != AF_INET6) 401 return -EINVAL; 402 403 addr_type = ipv6_addr_type(&usin->sin6_addr); 404 if (addr_type & IPV6_ADDR_MULTICAST) 405 return -EINVAL; 406 407 if (addr_type & IPV6_ADDR_MAPPED) { 408 daddr = &usin->sin6_addr; 409 if (ipv4_is_multicast(daddr->s6_addr32[3])) 410 return -EINVAL; 411 } 412 413 lock_sock(sk); 414 415 /* Must bind first - autobinding does not work */ 416 if (sock_flag(sk, SOCK_ZAPPED)) { 417 rc = -EINVAL; 418 goto out_sk; 419 } 420 421 rc = __ip6_datagram_connect(sk, uaddr, addr_len); 422 if (rc < 0) 423 goto out_sk; 424 425 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; 426 427 pn = l2tp_ip6_pernet(sock_net(sk)); 428 write_lock_bh(&pn->l2tp_ip6_lock); 429 hlist_del_init(&sk->sk_bind_node); 430 sk_add_bind_node(sk, &pn->l2tp_ip6_bind_table); 431 write_unlock_bh(&pn->l2tp_ip6_lock); 432 433 out_sk: 434 release_sock(sk); 435 436 return rc; 437 } 438 439 static int l2tp_ip6_disconnect(struct sock *sk, int flags) 440 { 441 if (sock_flag(sk, SOCK_ZAPPED)) 442 return 0; 443 444 return __udp_disconnect(sk, flags); 445 } 446 447 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr, 448 int peer) 449 { 450 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; 451 struct sock *sk = sock->sk; 452 struct ipv6_pinfo *np = inet6_sk(sk); 453 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk); 454 455 lsa->l2tp_family = AF_INET6; 456 lsa->l2tp_flowinfo = 0; 457 lsa->l2tp_scope_id = 0; 458 lsa->l2tp_unused = 0; 459 if (peer) { 460 if (!lsk->peer_conn_id) 461 return -ENOTCONN; 462 lsa->l2tp_conn_id = lsk->peer_conn_id; 463 lsa->l2tp_addr = sk->sk_v6_daddr; 464 if (inet6_test_bit(SNDFLOW, sk)) 465 lsa->l2tp_flowinfo = np->flow_label; 466 } else { 467 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 468 lsa->l2tp_addr = np->saddr; 469 else 470 lsa->l2tp_addr = sk->sk_v6_rcv_saddr; 471 472 lsa->l2tp_conn_id = lsk->conn_id; 473 } 474 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 475 lsa->l2tp_scope_id = READ_ONCE(sk->sk_bound_dev_if); 476 return sizeof(*lsa); 477 } 478 479 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb) 480 { 481 int rc; 482 483 /* Charge it to the socket, dropping if the queue is full. */ 484 rc = sock_queue_rcv_skb(sk, skb); 485 if (rc < 0) 486 goto drop; 487 488 return 0; 489 490 drop: 491 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); 492 kfree_skb(skb); 493 return -1; 494 } 495 496 static int l2tp_ip6_push_pending_frames(struct sock *sk) 497 { 498 struct sk_buff *skb; 499 __be32 *transhdr = NULL; 500 int err = 0; 501 502 skb = skb_peek(&sk->sk_write_queue); 503 if (!skb) 504 goto out; 505 506 transhdr = (__be32 *)skb_transport_header(skb); 507 *transhdr = 0; 508 509 err = ip6_push_pending_frames(sk); 510 511 out: 512 return err; 513 } 514 515 /* Userspace will call sendmsg() on the tunnel socket to send L2TP 516 * control frames. 517 */ 518 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 519 { 520 struct ipv6_txoptions opt_space; 521 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 522 struct in6_addr *daddr, *final_p, final; 523 struct ipv6_pinfo *np = inet6_sk(sk); 524 struct ipv6_txoptions *opt_to_free = NULL; 525 struct ipv6_txoptions *opt = NULL; 526 struct ip6_flowlabel *flowlabel = NULL; 527 struct dst_entry *dst = NULL; 528 struct flowi6 fl6; 529 struct ipcm6_cookie ipc6; 530 int addr_len = msg->msg_namelen; 531 int transhdrlen = 4; /* zero session-id */ 532 int ulen; 533 int err; 534 535 /* Rough check on arithmetic overflow, 536 * better check is made in ip6_append_data(). 537 */ 538 if (len > INT_MAX - transhdrlen) 539 return -EMSGSIZE; 540 541 /* Mirror BSD error message compatibility */ 542 if (msg->msg_flags & MSG_OOB) 543 return -EOPNOTSUPP; 544 545 /* Get and verify the address */ 546 memset(&fl6, 0, sizeof(fl6)); 547 548 fl6.flowi6_mark = READ_ONCE(sk->sk_mark); 549 fl6.flowi6_uid = sk_uid(sk); 550 551 ipcm6_init_sk(&ipc6, sk); 552 553 if (lsa) { 554 if (addr_len < SIN6_LEN_RFC2133) 555 return -EINVAL; 556 557 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6) 558 return -EAFNOSUPPORT; 559 560 daddr = &lsa->l2tp_addr; 561 if (inet6_test_bit(SNDFLOW, sk)) { 562 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK; 563 if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { 564 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 565 if (IS_ERR(flowlabel)) 566 return -EINVAL; 567 } 568 } 569 570 /* Otherwise it will be difficult to maintain 571 * sk->sk_dst_cache. 572 */ 573 if (sk->sk_state == TCP_ESTABLISHED && 574 ipv6_addr_equal(daddr, &sk->sk_v6_daddr)) 575 daddr = &sk->sk_v6_daddr; 576 577 if (addr_len >= sizeof(struct sockaddr_in6) && 578 lsa->l2tp_scope_id && 579 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL) 580 fl6.flowi6_oif = lsa->l2tp_scope_id; 581 } else { 582 if (sk->sk_state != TCP_ESTABLISHED) 583 return -EDESTADDRREQ; 584 585 daddr = &sk->sk_v6_daddr; 586 fl6.flowlabel = np->flow_label; 587 } 588 589 if (fl6.flowi6_oif == 0) 590 fl6.flowi6_oif = READ_ONCE(sk->sk_bound_dev_if); 591 592 if (msg->msg_controllen) { 593 opt = &opt_space; 594 memset(opt, 0, sizeof(struct ipv6_txoptions)); 595 opt->tot_len = sizeof(struct ipv6_txoptions); 596 ipc6.opt = opt; 597 598 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6); 599 if (err < 0) { 600 fl6_sock_release(flowlabel); 601 return err; 602 } 603 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) { 604 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 605 if (IS_ERR(flowlabel)) 606 return -EINVAL; 607 } 608 if (!(opt->opt_nflen | opt->opt_flen)) 609 opt = NULL; 610 } 611 612 if (!opt) { 613 opt = txopt_get(np); 614 opt_to_free = opt; 615 } 616 if (flowlabel) 617 opt = fl6_merge_options(&opt_space, flowlabel, opt); 618 opt = ipv6_fixup_options(&opt_space, opt); 619 ipc6.opt = opt; 620 621 fl6.flowi6_proto = sk->sk_protocol; 622 if (!ipv6_addr_any(daddr)) 623 fl6.daddr = *daddr; 624 else 625 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ 626 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr)) 627 fl6.saddr = np->saddr; 628 629 final_p = fl6_update_dst(&fl6, opt, &final); 630 631 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 632 fl6.flowi6_oif = READ_ONCE(np->mcast_oif); 633 else if (!fl6.flowi6_oif) 634 fl6.flowi6_oif = READ_ONCE(np->ucast_oif); 635 636 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); 637 638 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); 639 640 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); 641 if (IS_ERR(dst)) { 642 err = PTR_ERR(dst); 643 goto out; 644 } 645 646 if (ipc6.hlimit < 0) 647 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 648 649 if (msg->msg_flags & MSG_CONFIRM) 650 goto do_confirm; 651 652 back_from_confirm: 653 lock_sock(sk); 654 ulen = len + (skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0); 655 err = ip6_append_data(sk, ip_generic_getfrag, msg, 656 ulen, transhdrlen, &ipc6, 657 &fl6, dst_rt6_info(dst), 658 msg->msg_flags); 659 if (err) 660 ip6_flush_pending_frames(sk); 661 else if (!(msg->msg_flags & MSG_MORE)) 662 err = l2tp_ip6_push_pending_frames(sk); 663 release_sock(sk); 664 done: 665 dst_release(dst); 666 out: 667 fl6_sock_release(flowlabel); 668 txopt_put(opt_to_free); 669 670 return err < 0 ? err : len; 671 672 do_confirm: 673 if (msg->msg_flags & MSG_PROBE) 674 dst_confirm_neigh(dst, &fl6.daddr); 675 if (!(msg->msg_flags & MSG_PROBE) || len) 676 goto back_from_confirm; 677 err = 0; 678 goto done; 679 } 680 681 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 682 int flags, int *addr_len) 683 { 684 struct ipv6_pinfo *np = inet6_sk(sk); 685 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); 686 size_t copied = 0; 687 int err = -EOPNOTSUPP; 688 struct sk_buff *skb; 689 690 if (flags & MSG_OOB) 691 goto out; 692 693 if (flags & MSG_ERRQUEUE) 694 return ipv6_recv_error(sk, msg, len, addr_len); 695 696 skb = skb_recv_datagram(sk, flags, &err); 697 if (!skb) 698 goto out; 699 700 copied = skb->len; 701 if (len < copied) { 702 msg->msg_flags |= MSG_TRUNC; 703 copied = len; 704 } 705 706 err = skb_copy_datagram_msg(skb, 0, msg, copied); 707 if (err) 708 goto done; 709 710 sock_recv_timestamp(msg, sk, skb); 711 712 /* Copy the address. */ 713 if (lsa) { 714 lsa->l2tp_family = AF_INET6; 715 lsa->l2tp_unused = 0; 716 lsa->l2tp_addr = ipv6_hdr(skb)->saddr; 717 lsa->l2tp_flowinfo = 0; 718 lsa->l2tp_scope_id = 0; 719 lsa->l2tp_conn_id = 0; 720 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) 721 lsa->l2tp_scope_id = inet6_iif(skb); 722 *addr_len = sizeof(*lsa); 723 } 724 725 if (np->rxopt.all) 726 ip6_datagram_recv_ctl(sk, msg, skb); 727 728 if (flags & MSG_TRUNC) 729 copied = skb->len; 730 done: 731 skb_free_datagram(sk, skb); 732 out: 733 return err ? err : copied; 734 } 735 736 static struct proto l2tp_ip6_prot = { 737 .name = "L2TP/IPv6", 738 .owner = THIS_MODULE, 739 .init = l2tp_ip6_open, 740 .close = l2tp_ip6_close, 741 .bind = l2tp_ip6_bind, 742 .connect = l2tp_ip6_connect, 743 .disconnect = l2tp_ip6_disconnect, 744 .ioctl = l2tp_ioctl, 745 .destroy = l2tp_ip6_destroy_sock, 746 .setsockopt = ipv6_setsockopt, 747 .getsockopt = ipv6_getsockopt, 748 .sendmsg = l2tp_ip6_sendmsg, 749 .recvmsg = l2tp_ip6_recvmsg, 750 .backlog_rcv = l2tp_ip6_backlog_recv, 751 .hash = l2tp_ip6_hash, 752 .unhash = l2tp_ip6_unhash, 753 .obj_size = sizeof(struct l2tp_ip6_sock), 754 .ipv6_pinfo_offset = offsetof(struct l2tp_ip6_sock, inet6), 755 }; 756 757 static const struct proto_ops l2tp_ip6_ops = { 758 .family = PF_INET6, 759 .owner = THIS_MODULE, 760 .release = inet6_release, 761 .bind = inet6_bind, 762 .connect = inet_dgram_connect, 763 .socketpair = sock_no_socketpair, 764 .accept = sock_no_accept, 765 .getname = l2tp_ip6_getname, 766 .poll = datagram_poll, 767 .ioctl = inet6_ioctl, 768 .gettstamp = sock_gettstamp, 769 .listen = sock_no_listen, 770 .shutdown = inet_shutdown, 771 .setsockopt = sock_common_setsockopt, 772 .getsockopt = sock_common_getsockopt, 773 .sendmsg = inet_sendmsg, 774 .recvmsg = sock_common_recvmsg, 775 .mmap = sock_no_mmap, 776 #ifdef CONFIG_COMPAT 777 .compat_ioctl = inet6_compat_ioctl, 778 #endif 779 }; 780 781 static struct inet_protosw l2tp_ip6_protosw = { 782 .type = SOCK_DGRAM, 783 .protocol = IPPROTO_L2TP, 784 .prot = &l2tp_ip6_prot, 785 .ops = &l2tp_ip6_ops, 786 }; 787 788 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = { 789 .handler = l2tp_ip6_recv, 790 }; 791 792 static __net_init int l2tp_ip6_init_net(struct net *net) 793 { 794 struct l2tp_ip6_net *pn = net_generic(net, l2tp_ip6_net_id); 795 796 rwlock_init(&pn->l2tp_ip6_lock); 797 INIT_HLIST_HEAD(&pn->l2tp_ip6_table); 798 INIT_HLIST_HEAD(&pn->l2tp_ip6_bind_table); 799 return 0; 800 } 801 802 static __net_exit void l2tp_ip6_exit_net(struct net *net) 803 { 804 struct l2tp_ip6_net *pn = l2tp_ip6_pernet(net); 805 806 write_lock_bh(&pn->l2tp_ip6_lock); 807 WARN_ON_ONCE(hlist_count_nodes(&pn->l2tp_ip6_table) != 0); 808 WARN_ON_ONCE(hlist_count_nodes(&pn->l2tp_ip6_bind_table) != 0); 809 write_unlock_bh(&pn->l2tp_ip6_lock); 810 } 811 812 static struct pernet_operations l2tp_ip6_net_ops = { 813 .init = l2tp_ip6_init_net, 814 .exit = l2tp_ip6_exit_net, 815 .id = &l2tp_ip6_net_id, 816 .size = sizeof(struct l2tp_ip6_net), 817 }; 818 819 static int __init l2tp_ip6_init(void) 820 { 821 int err; 822 823 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n"); 824 825 err = register_pernet_device(&l2tp_ip6_net_ops); 826 if (err) 827 goto out; 828 829 err = proto_register(&l2tp_ip6_prot, 1); 830 if (err != 0) 831 goto out1; 832 833 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 834 if (err) 835 goto out2; 836 837 inet6_register_protosw(&l2tp_ip6_protosw); 838 return 0; 839 840 out2: 841 proto_unregister(&l2tp_ip6_prot); 842 out1: 843 unregister_pernet_device(&l2tp_ip6_net_ops); 844 out: 845 return err; 846 } 847 848 static void __exit l2tp_ip6_exit(void) 849 { 850 inet6_unregister_protosw(&l2tp_ip6_protosw); 851 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); 852 proto_unregister(&l2tp_ip6_prot); 853 unregister_pernet_device(&l2tp_ip6_net_ops); 854 } 855 856 module_init(l2tp_ip6_init); 857 module_exit(l2tp_ip6_exit); 858 859 MODULE_LICENSE("GPL"); 860 MODULE_AUTHOR("Chris Elston <celston@katalix.com>"); 861 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6"); 862 MODULE_VERSION("1.0"); 863 864 /* Use the values of SOCK_DGRAM (2) as type and IPPROTO_L2TP (115) as protocol, 865 * because __stringify doesn't like enums 866 */ 867 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 115, 2); 868 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, 115); 869