1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * TCP over IPv6 4 * Linux INET6 implementation 5 * 6 * Authors: 7 * Pedro Roque <roque@di.fc.ul.pt> 8 * 9 * Based on: 10 * linux/net/ipv4/tcp.c 11 * linux/net/ipv4/tcp_input.c 12 * linux/net/ipv4/tcp_output.c 13 * 14 * Fixes: 15 * Hideaki YOSHIFUJI : sin6_scope_id support 16 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which 17 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind 18 * a single port at the same time. 19 * YOSHIFUJI Hideaki @USAGI: convert /proc/net/tcp6 to seq_file. 20 */ 21 22 #include <linux/bottom_half.h> 23 #include <linux/module.h> 24 #include <linux/errno.h> 25 #include <linux/types.h> 26 #include <linux/socket.h> 27 #include <linux/sockios.h> 28 #include <linux/net.h> 29 #include <linux/jiffies.h> 30 #include <linux/in.h> 31 #include <linux/in6.h> 32 #include <linux/netdevice.h> 33 #include <linux/init.h> 34 #include <linux/jhash.h> 35 #include <linux/ipsec.h> 36 #include <linux/times.h> 37 #include <linux/slab.h> 38 #include <linux/uaccess.h> 39 #include <linux/ipv6.h> 40 #include <linux/icmpv6.h> 41 #include <linux/random.h> 42 #include <linux/indirect_call_wrapper.h> 43 44 #include <net/tcp.h> 45 #include <net/ndisc.h> 46 #include <net/inet6_hashtables.h> 47 #include <net/inet6_connection_sock.h> 48 #include <net/ipv6.h> 49 #include <net/transp_v6.h> 50 #include <net/addrconf.h> 51 #include <net/ip6_route.h> 52 #include <net/ip6_checksum.h> 53 #include <net/inet_ecn.h> 54 #include <net/protocol.h> 55 #include <net/xfrm.h> 56 #include <net/snmp.h> 57 #include <net/dsfield.h> 58 #include <net/timewait_sock.h> 59 #include <net/inet_common.h> 60 #include <net/secure_seq.h> 61 #include <net/busy_poll.h> 62 63 #include <linux/proc_fs.h> 64 #include <linux/seq_file.h> 65 66 #include <crypto/hash.h> 67 #include <linux/scatterlist.h> 68 69 #include <trace/events/tcp.h> 70 71 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb); 72 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, 73 struct request_sock *req); 74 75 INDIRECT_CALLABLE_SCOPE int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb); 76 77 static const struct inet_connection_sock_af_ops ipv6_mapped; 78 const struct inet_connection_sock_af_ops ipv6_specific; 79 #ifdef CONFIG_TCP_MD5SIG 80 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific; 81 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific; 82 #else 83 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk, 84 const struct in6_addr *addr, 85 int l3index) 86 { 87 return NULL; 88 } 89 #endif 90 91 /* Helper returning the inet6 address from a given tcp socket. 92 * It can be used in TCP stack instead of inet6_sk(sk). 93 * This avoids a dereference and allow compiler optimizations. 94 * It is a specialized version of inet6_sk_generic(). 95 */ 96 static struct ipv6_pinfo *tcp_inet6_sk(const struct sock *sk) 97 { 98 unsigned int offset = sizeof(struct tcp6_sock) - sizeof(struct ipv6_pinfo); 99 100 return (struct ipv6_pinfo *)(((u8 *)sk) + offset); 101 } 102 103 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) 104 { 105 struct dst_entry *dst = skb_dst(skb); 106 107 if (dst && dst_hold_safe(dst)) { 108 const struct rt6_info *rt = (const struct rt6_info *)dst; 109 110 rcu_assign_pointer(sk->sk_rx_dst, dst); 111 sk->sk_rx_dst_ifindex = skb->skb_iif; 112 sk->sk_rx_dst_cookie = rt6_get_cookie(rt); 113 } 114 } 115 116 static u32 tcp_v6_init_seq(const struct sk_buff *skb) 117 { 118 return secure_tcpv6_seq(ipv6_hdr(skb)->daddr.s6_addr32, 119 ipv6_hdr(skb)->saddr.s6_addr32, 120 tcp_hdr(skb)->dest, 121 tcp_hdr(skb)->source); 122 } 123 124 static u32 tcp_v6_init_ts_off(const struct net *net, const struct sk_buff *skb) 125 { 126 return secure_tcpv6_ts_off(net, ipv6_hdr(skb)->daddr.s6_addr32, 127 ipv6_hdr(skb)->saddr.s6_addr32); 128 } 129 130 static int tcp_v6_pre_connect(struct sock *sk, struct sockaddr *uaddr, 131 int addr_len) 132 { 133 /* This check is replicated from tcp_v6_connect() and intended to 134 * prevent BPF program called below from accessing bytes that are out 135 * of the bound specified by user in addr_len. 136 */ 137 if (addr_len < SIN6_LEN_RFC2133) 138 return -EINVAL; 139 140 sock_owned_by_me(sk); 141 142 return BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr); 143 } 144 145 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 146 int addr_len) 147 { 148 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr; 149 struct inet_connection_sock *icsk = inet_csk(sk); 150 struct in6_addr *saddr = NULL, *final_p, final; 151 struct inet_timewait_death_row *tcp_death_row; 152 struct ipv6_pinfo *np = tcp_inet6_sk(sk); 153 struct inet_sock *inet = inet_sk(sk); 154 struct tcp_sock *tp = tcp_sk(sk); 155 struct net *net = sock_net(sk); 156 struct ipv6_txoptions *opt; 157 struct dst_entry *dst; 158 struct flowi6 fl6; 159 int addr_type; 160 int err; 161 162 if (addr_len < SIN6_LEN_RFC2133) 163 return -EINVAL; 164 165 if (usin->sin6_family != AF_INET6) 166 return -EAFNOSUPPORT; 167 168 memset(&fl6, 0, sizeof(fl6)); 169 170 if (np->sndflow) { 171 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK; 172 IP6_ECN_flow_init(fl6.flowlabel); 173 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) { 174 struct ip6_flowlabel *flowlabel; 175 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); 176 if (IS_ERR(flowlabel)) 177 return -EINVAL; 178 fl6_sock_release(flowlabel); 179 } 180 } 181 182 /* 183 * connect() to INADDR_ANY means loopback (BSD'ism). 184 */ 185 186 if (ipv6_addr_any(&usin->sin6_addr)) { 187 if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)) 188 ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK), 189 &usin->sin6_addr); 190 else 191 usin->sin6_addr = in6addr_loopback; 192 } 193 194 addr_type = ipv6_addr_type(&usin->sin6_addr); 195 196 if (addr_type & IPV6_ADDR_MULTICAST) 197 return -ENETUNREACH; 198 199 if (addr_type&IPV6_ADDR_LINKLOCAL) { 200 if (addr_len >= sizeof(struct sockaddr_in6) && 201 usin->sin6_scope_id) { 202 /* If interface is set while binding, indices 203 * must coincide. 204 */ 205 if (!sk_dev_equal_l3scope(sk, usin->sin6_scope_id)) 206 return -EINVAL; 207 208 sk->sk_bound_dev_if = usin->sin6_scope_id; 209 } 210 211 /* Connect to link-local address requires an interface */ 212 if (!sk->sk_bound_dev_if) 213 return -EINVAL; 214 } 215 216 if (tp->rx_opt.ts_recent_stamp && 217 !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) { 218 tp->rx_opt.ts_recent = 0; 219 tp->rx_opt.ts_recent_stamp = 0; 220 WRITE_ONCE(tp->write_seq, 0); 221 } 222 223 sk->sk_v6_daddr = usin->sin6_addr; 224 np->flow_label = fl6.flowlabel; 225 226 /* 227 * TCP over IPv4 228 */ 229 230 if (addr_type & IPV6_ADDR_MAPPED) { 231 u32 exthdrlen = icsk->icsk_ext_hdr_len; 232 struct sockaddr_in sin; 233 234 if (ipv6_only_sock(sk)) 235 return -ENETUNREACH; 236 237 sin.sin_family = AF_INET; 238 sin.sin_port = usin->sin6_port; 239 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3]; 240 241 /* Paired with READ_ONCE() in tcp_(get|set)sockopt() */ 242 WRITE_ONCE(icsk->icsk_af_ops, &ipv6_mapped); 243 if (sk_is_mptcp(sk)) 244 mptcpv6_handle_mapped(sk, true); 245 sk->sk_backlog_rcv = tcp_v4_do_rcv; 246 #ifdef CONFIG_TCP_MD5SIG 247 tp->af_specific = &tcp_sock_ipv6_mapped_specific; 248 #endif 249 250 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin)); 251 252 if (err) { 253 icsk->icsk_ext_hdr_len = exthdrlen; 254 /* Paired with READ_ONCE() in tcp_(get|set)sockopt() */ 255 WRITE_ONCE(icsk->icsk_af_ops, &ipv6_specific); 256 if (sk_is_mptcp(sk)) 257 mptcpv6_handle_mapped(sk, false); 258 sk->sk_backlog_rcv = tcp_v6_do_rcv; 259 #ifdef CONFIG_TCP_MD5SIG 260 tp->af_specific = &tcp_sock_ipv6_specific; 261 #endif 262 goto failure; 263 } 264 np->saddr = sk->sk_v6_rcv_saddr; 265 266 return err; 267 } 268 269 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) 270 saddr = &sk->sk_v6_rcv_saddr; 271 272 fl6.flowi6_proto = IPPROTO_TCP; 273 fl6.daddr = sk->sk_v6_daddr; 274 fl6.saddr = saddr ? *saddr : np->saddr; 275 fl6.flowi6_oif = sk->sk_bound_dev_if; 276 fl6.flowi6_mark = sk->sk_mark; 277 fl6.fl6_dport = usin->sin6_port; 278 fl6.fl6_sport = inet->inet_sport; 279 fl6.flowi6_uid = sk->sk_uid; 280 281 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk)); 282 final_p = fl6_update_dst(&fl6, opt, &final); 283 284 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); 285 286 dst = ip6_dst_lookup_flow(net, sk, &fl6, final_p); 287 if (IS_ERR(dst)) { 288 err = PTR_ERR(dst); 289 goto failure; 290 } 291 292 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row; 293 294 if (!saddr) { 295 saddr = &fl6.saddr; 296 297 err = inet_bhash2_update_saddr(sk, saddr, AF_INET6); 298 if (err) 299 goto failure; 300 } 301 302 /* set the source address */ 303 np->saddr = *saddr; 304 inet->inet_rcv_saddr = LOOPBACK4_IPV6; 305 306 sk->sk_gso_type = SKB_GSO_TCPV6; 307 ip6_dst_store(sk, dst, NULL, NULL); 308 309 icsk->icsk_ext_hdr_len = 0; 310 if (opt) 311 icsk->icsk_ext_hdr_len = opt->opt_flen + 312 opt->opt_nflen; 313 314 tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr); 315 316 inet->inet_dport = usin->sin6_port; 317 318 tcp_set_state(sk, TCP_SYN_SENT); 319 err = inet6_hash_connect(tcp_death_row, sk); 320 if (err) 321 goto late_failure; 322 323 sk_set_txhash(sk); 324 325 if (likely(!tp->repair)) { 326 if (!tp->write_seq) 327 WRITE_ONCE(tp->write_seq, 328 secure_tcpv6_seq(np->saddr.s6_addr32, 329 sk->sk_v6_daddr.s6_addr32, 330 inet->inet_sport, 331 inet->inet_dport)); 332 tp->tsoffset = secure_tcpv6_ts_off(net, np->saddr.s6_addr32, 333 sk->sk_v6_daddr.s6_addr32); 334 } 335 336 if (tcp_fastopen_defer_connect(sk, &err)) 337 return err; 338 if (err) 339 goto late_failure; 340 341 err = tcp_connect(sk); 342 if (err) 343 goto late_failure; 344 345 return 0; 346 347 late_failure: 348 tcp_set_state(sk, TCP_CLOSE); 349 inet_bhash2_reset_saddr(sk); 350 failure: 351 inet->inet_dport = 0; 352 sk->sk_route_caps = 0; 353 return err; 354 } 355 356 static void tcp_v6_mtu_reduced(struct sock *sk) 357 { 358 struct dst_entry *dst; 359 u32 mtu; 360 361 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) 362 return; 363 364 mtu = READ_ONCE(tcp_sk(sk)->mtu_info); 365 366 /* Drop requests trying to increase our current mss. 367 * Check done in __ip6_rt_update_pmtu() is too late. 368 */ 369 if (tcp_mtu_to_mss(sk, mtu) >= tcp_sk(sk)->mss_cache) 370 return; 371 372 dst = inet6_csk_update_pmtu(sk, mtu); 373 if (!dst) 374 return; 375 376 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) { 377 tcp_sync_mss(sk, dst_mtu(dst)); 378 tcp_simple_retransmit(sk); 379 } 380 } 381 382 static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 383 u8 type, u8 code, int offset, __be32 info) 384 { 385 const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data; 386 const struct tcphdr *th = (struct tcphdr *)(skb->data+offset); 387 struct net *net = dev_net(skb->dev); 388 struct request_sock *fastopen; 389 struct ipv6_pinfo *np; 390 struct tcp_sock *tp; 391 __u32 seq, snd_una; 392 struct sock *sk; 393 bool fatal; 394 int err; 395 396 sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, 397 &hdr->daddr, th->dest, 398 &hdr->saddr, ntohs(th->source), 399 skb->dev->ifindex, inet6_sdif(skb)); 400 401 if (!sk) { 402 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), 403 ICMP6_MIB_INERRORS); 404 return -ENOENT; 405 } 406 407 if (sk->sk_state == TCP_TIME_WAIT) { 408 inet_twsk_put(inet_twsk(sk)); 409 return 0; 410 } 411 seq = ntohl(th->seq); 412 fatal = icmpv6_err_convert(type, code, &err); 413 if (sk->sk_state == TCP_NEW_SYN_RECV) { 414 tcp_req_err(sk, seq, fatal); 415 return 0; 416 } 417 418 bh_lock_sock(sk); 419 if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG) 420 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); 421 422 if (sk->sk_state == TCP_CLOSE) 423 goto out; 424 425 if (static_branch_unlikely(&ip6_min_hopcount)) { 426 /* min_hopcount can be changed concurrently from do_ipv6_setsockopt() */ 427 if (ipv6_hdr(skb)->hop_limit < READ_ONCE(tcp_inet6_sk(sk)->min_hopcount)) { 428 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); 429 goto out; 430 } 431 } 432 433 tp = tcp_sk(sk); 434 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */ 435 fastopen = rcu_dereference(tp->fastopen_rsk); 436 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una; 437 if (sk->sk_state != TCP_LISTEN && 438 !between(seq, snd_una, tp->snd_nxt)) { 439 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 440 goto out; 441 } 442 443 np = tcp_inet6_sk(sk); 444 445 if (type == NDISC_REDIRECT) { 446 if (!sock_owned_by_user(sk)) { 447 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie); 448 449 if (dst) 450 dst->ops->redirect(dst, sk, skb); 451 } 452 goto out; 453 } 454 455 if (type == ICMPV6_PKT_TOOBIG) { 456 u32 mtu = ntohl(info); 457 458 /* We are not interested in TCP_LISTEN and open_requests 459 * (SYN-ACKs send out by Linux are always <576bytes so 460 * they should go through unfragmented). 461 */ 462 if (sk->sk_state == TCP_LISTEN) 463 goto out; 464 465 if (!ip6_sk_accept_pmtu(sk)) 466 goto out; 467 468 if (mtu < IPV6_MIN_MTU) 469 goto out; 470 471 WRITE_ONCE(tp->mtu_info, mtu); 472 473 if (!sock_owned_by_user(sk)) 474 tcp_v6_mtu_reduced(sk); 475 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, 476 &sk->sk_tsq_flags)) 477 sock_hold(sk); 478 goto out; 479 } 480 481 482 /* Might be for an request_sock */ 483 switch (sk->sk_state) { 484 case TCP_SYN_SENT: 485 case TCP_SYN_RECV: 486 /* Only in fast or simultaneous open. If a fast open socket is 487 * already accepted it is treated as a connected one below. 488 */ 489 if (fastopen && !fastopen->sk) 490 break; 491 492 ipv6_icmp_error(sk, skb, err, th->dest, ntohl(info), (u8 *)th); 493 494 if (!sock_owned_by_user(sk)) { 495 sk->sk_err = err; 496 sk_error_report(sk); /* Wake people up to see the error (see connect in sock.c) */ 497 498 tcp_done(sk); 499 } else 500 sk->sk_err_soft = err; 501 goto out; 502 case TCP_LISTEN: 503 break; 504 default: 505 /* check if this ICMP message allows revert of backoff. 506 * (see RFC 6069) 507 */ 508 if (!fastopen && type == ICMPV6_DEST_UNREACH && 509 code == ICMPV6_NOROUTE) 510 tcp_ld_RTO_revert(sk, seq); 511 } 512 513 if (!sock_owned_by_user(sk) && np->recverr) { 514 sk->sk_err = err; 515 sk_error_report(sk); 516 } else 517 sk->sk_err_soft = err; 518 519 out: 520 bh_unlock_sock(sk); 521 sock_put(sk); 522 return 0; 523 } 524 525 526 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst, 527 struct flowi *fl, 528 struct request_sock *req, 529 struct tcp_fastopen_cookie *foc, 530 enum tcp_synack_type synack_type, 531 struct sk_buff *syn_skb) 532 { 533 struct inet_request_sock *ireq = inet_rsk(req); 534 struct ipv6_pinfo *np = tcp_inet6_sk(sk); 535 struct ipv6_txoptions *opt; 536 struct flowi6 *fl6 = &fl->u.ip6; 537 struct sk_buff *skb; 538 int err = -ENOMEM; 539 u8 tclass; 540 541 /* First, grab a route. */ 542 if (!dst && (dst = inet6_csk_route_req(sk, fl6, req, 543 IPPROTO_TCP)) == NULL) 544 goto done; 545 546 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb); 547 548 if (skb) { 549 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr, 550 &ireq->ir_v6_rmt_addr); 551 552 fl6->daddr = ireq->ir_v6_rmt_addr; 553 if (np->repflow && ireq->pktopts) 554 fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts)); 555 556 tclass = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) ? 557 (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) | 558 (np->tclass & INET_ECN_MASK) : 559 np->tclass; 560 561 if (!INET_ECN_is_capable(tclass) && 562 tcp_bpf_ca_needs_ecn((struct sock *)req)) 563 tclass |= INET_ECN_ECT_0; 564 565 rcu_read_lock(); 566 opt = ireq->ipv6_opt; 567 if (!opt) 568 opt = rcu_dereference(np->opt); 569 err = ip6_xmit(sk, skb, fl6, skb->mark ? : sk->sk_mark, opt, 570 tclass, sk->sk_priority); 571 rcu_read_unlock(); 572 err = net_xmit_eval(err); 573 } 574 575 done: 576 return err; 577 } 578 579 580 static void tcp_v6_reqsk_destructor(struct request_sock *req) 581 { 582 kfree(inet_rsk(req)->ipv6_opt); 583 consume_skb(inet_rsk(req)->pktopts); 584 } 585 586 #ifdef CONFIG_TCP_MD5SIG 587 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk, 588 const struct in6_addr *addr, 589 int l3index) 590 { 591 return tcp_md5_do_lookup(sk, l3index, 592 (union tcp_md5_addr *)addr, AF_INET6); 593 } 594 595 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk, 596 const struct sock *addr_sk) 597 { 598 int l3index; 599 600 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), 601 addr_sk->sk_bound_dev_if); 602 return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr, 603 l3index); 604 } 605 606 static int tcp_v6_parse_md5_keys(struct sock *sk, int optname, 607 sockptr_t optval, int optlen) 608 { 609 struct tcp_md5sig cmd; 610 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr; 611 int l3index = 0; 612 u8 prefixlen; 613 u8 flags; 614 615 if (optlen < sizeof(cmd)) 616 return -EINVAL; 617 618 if (copy_from_sockptr(&cmd, optval, sizeof(cmd))) 619 return -EFAULT; 620 621 if (sin6->sin6_family != AF_INET6) 622 return -EINVAL; 623 624 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX; 625 626 if (optname == TCP_MD5SIG_EXT && 627 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) { 628 prefixlen = cmd.tcpm_prefixlen; 629 if (prefixlen > 128 || (ipv6_addr_v4mapped(&sin6->sin6_addr) && 630 prefixlen > 32)) 631 return -EINVAL; 632 } else { 633 prefixlen = ipv6_addr_v4mapped(&sin6->sin6_addr) ? 32 : 128; 634 } 635 636 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex && 637 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) { 638 struct net_device *dev; 639 640 rcu_read_lock(); 641 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex); 642 if (dev && netif_is_l3_master(dev)) 643 l3index = dev->ifindex; 644 rcu_read_unlock(); 645 646 /* ok to reference set/not set outside of rcu; 647 * right now device MUST be an L3 master 648 */ 649 if (!dev || !l3index) 650 return -EINVAL; 651 } 652 653 if (!cmd.tcpm_keylen) { 654 if (ipv6_addr_v4mapped(&sin6->sin6_addr)) 655 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3], 656 AF_INET, prefixlen, 657 l3index, flags); 658 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr, 659 AF_INET6, prefixlen, l3index, flags); 660 } 661 662 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) 663 return -EINVAL; 664 665 if (ipv6_addr_v4mapped(&sin6->sin6_addr)) 666 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3], 667 AF_INET, prefixlen, l3index, flags, 668 cmd.tcpm_key, cmd.tcpm_keylen, 669 GFP_KERNEL); 670 671 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr, 672 AF_INET6, prefixlen, l3index, flags, 673 cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL); 674 } 675 676 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp, 677 const struct in6_addr *daddr, 678 const struct in6_addr *saddr, 679 const struct tcphdr *th, int nbytes) 680 { 681 struct tcp6_pseudohdr *bp; 682 struct scatterlist sg; 683 struct tcphdr *_th; 684 685 bp = hp->scratch; 686 /* 1. TCP pseudo-header (RFC2460) */ 687 bp->saddr = *saddr; 688 bp->daddr = *daddr; 689 bp->protocol = cpu_to_be32(IPPROTO_TCP); 690 bp->len = cpu_to_be32(nbytes); 691 692 _th = (struct tcphdr *)(bp + 1); 693 memcpy(_th, th, sizeof(*th)); 694 _th->check = 0; 695 696 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th)); 697 ahash_request_set_crypt(hp->md5_req, &sg, NULL, 698 sizeof(*bp) + sizeof(*th)); 699 return crypto_ahash_update(hp->md5_req); 700 } 701 702 static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 703 const struct in6_addr *daddr, struct in6_addr *saddr, 704 const struct tcphdr *th) 705 { 706 struct tcp_md5sig_pool *hp; 707 struct ahash_request *req; 708 709 hp = tcp_get_md5sig_pool(); 710 if (!hp) 711 goto clear_hash_noput; 712 req = hp->md5_req; 713 714 if (crypto_ahash_init(req)) 715 goto clear_hash; 716 if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2)) 717 goto clear_hash; 718 if (tcp_md5_hash_key(hp, key)) 719 goto clear_hash; 720 ahash_request_set_crypt(req, NULL, md5_hash, 0); 721 if (crypto_ahash_final(req)) 722 goto clear_hash; 723 724 tcp_put_md5sig_pool(); 725 return 0; 726 727 clear_hash: 728 tcp_put_md5sig_pool(); 729 clear_hash_noput: 730 memset(md5_hash, 0, 16); 731 return 1; 732 } 733 734 static int tcp_v6_md5_hash_skb(char *md5_hash, 735 const struct tcp_md5sig_key *key, 736 const struct sock *sk, 737 const struct sk_buff *skb) 738 { 739 const struct in6_addr *saddr, *daddr; 740 struct tcp_md5sig_pool *hp; 741 struct ahash_request *req; 742 const struct tcphdr *th = tcp_hdr(skb); 743 744 if (sk) { /* valid for establish/request sockets */ 745 saddr = &sk->sk_v6_rcv_saddr; 746 daddr = &sk->sk_v6_daddr; 747 } else { 748 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 749 saddr = &ip6h->saddr; 750 daddr = &ip6h->daddr; 751 } 752 753 hp = tcp_get_md5sig_pool(); 754 if (!hp) 755 goto clear_hash_noput; 756 req = hp->md5_req; 757 758 if (crypto_ahash_init(req)) 759 goto clear_hash; 760 761 if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len)) 762 goto clear_hash; 763 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) 764 goto clear_hash; 765 if (tcp_md5_hash_key(hp, key)) 766 goto clear_hash; 767 ahash_request_set_crypt(req, NULL, md5_hash, 0); 768 if (crypto_ahash_final(req)) 769 goto clear_hash; 770 771 tcp_put_md5sig_pool(); 772 return 0; 773 774 clear_hash: 775 tcp_put_md5sig_pool(); 776 clear_hash_noput: 777 memset(md5_hash, 0, 16); 778 return 1; 779 } 780 781 #endif 782 783 static void tcp_v6_init_req(struct request_sock *req, 784 const struct sock *sk_listener, 785 struct sk_buff *skb) 786 { 787 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags); 788 struct inet_request_sock *ireq = inet_rsk(req); 789 const struct ipv6_pinfo *np = tcp_inet6_sk(sk_listener); 790 791 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr; 792 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr; 793 794 /* So that link locals have meaning */ 795 if ((!sk_listener->sk_bound_dev_if || l3_slave) && 796 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL) 797 ireq->ir_iif = tcp_v6_iif(skb); 798 799 if (!TCP_SKB_CB(skb)->tcp_tw_isn && 800 (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) || 801 np->rxopt.bits.rxinfo || 802 np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim || 803 np->rxopt.bits.rxohlim || np->repflow)) { 804 refcount_inc(&skb->users); 805 ireq->pktopts = skb; 806 } 807 } 808 809 static struct dst_entry *tcp_v6_route_req(const struct sock *sk, 810 struct sk_buff *skb, 811 struct flowi *fl, 812 struct request_sock *req) 813 { 814 tcp_v6_init_req(req, sk, skb); 815 816 if (security_inet_conn_request(sk, skb, req)) 817 return NULL; 818 819 return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP); 820 } 821 822 struct request_sock_ops tcp6_request_sock_ops __read_mostly = { 823 .family = AF_INET6, 824 .obj_size = sizeof(struct tcp6_request_sock), 825 .rtx_syn_ack = tcp_rtx_synack, 826 .send_ack = tcp_v6_reqsk_send_ack, 827 .destructor = tcp_v6_reqsk_destructor, 828 .send_reset = tcp_v6_send_reset, 829 .syn_ack_timeout = tcp_syn_ack_timeout, 830 }; 831 832 const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = { 833 .mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - 834 sizeof(struct ipv6hdr), 835 #ifdef CONFIG_TCP_MD5SIG 836 .req_md5_lookup = tcp_v6_md5_lookup, 837 .calc_md5_hash = tcp_v6_md5_hash_skb, 838 #endif 839 #ifdef CONFIG_SYN_COOKIES 840 .cookie_init_seq = cookie_v6_init_sequence, 841 #endif 842 .route_req = tcp_v6_route_req, 843 .init_seq = tcp_v6_init_seq, 844 .init_ts_off = tcp_v6_init_ts_off, 845 .send_synack = tcp_v6_send_synack, 846 }; 847 848 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq, 849 u32 ack, u32 win, u32 tsval, u32 tsecr, 850 int oif, struct tcp_md5sig_key *key, int rst, 851 u8 tclass, __be32 label, u32 priority, u32 txhash) 852 { 853 const struct tcphdr *th = tcp_hdr(skb); 854 struct tcphdr *t1; 855 struct sk_buff *buff; 856 struct flowi6 fl6; 857 struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); 858 struct sock *ctl_sk = net->ipv6.tcp_sk; 859 unsigned int tot_len = sizeof(struct tcphdr); 860 __be32 mrst = 0, *topt; 861 struct dst_entry *dst; 862 __u32 mark = 0; 863 864 if (tsecr) 865 tot_len += TCPOLEN_TSTAMP_ALIGNED; 866 #ifdef CONFIG_TCP_MD5SIG 867 if (key) 868 tot_len += TCPOLEN_MD5SIG_ALIGNED; 869 #endif 870 871 #ifdef CONFIG_MPTCP 872 if (rst && !key) { 873 mrst = mptcp_reset_option(skb); 874 875 if (mrst) 876 tot_len += sizeof(__be32); 877 } 878 #endif 879 880 buff = alloc_skb(MAX_TCP_HEADER, GFP_ATOMIC); 881 if (!buff) 882 return; 883 884 skb_reserve(buff, MAX_TCP_HEADER); 885 886 t1 = skb_push(buff, tot_len); 887 skb_reset_transport_header(buff); 888 889 /* Swap the send and the receive. */ 890 memset(t1, 0, sizeof(*t1)); 891 t1->dest = th->source; 892 t1->source = th->dest; 893 t1->doff = tot_len / 4; 894 t1->seq = htonl(seq); 895 t1->ack_seq = htonl(ack); 896 t1->ack = !rst || !th->ack; 897 t1->rst = rst; 898 t1->window = htons(win); 899 900 topt = (__be32 *)(t1 + 1); 901 902 if (tsecr) { 903 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 904 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); 905 *topt++ = htonl(tsval); 906 *topt++ = htonl(tsecr); 907 } 908 909 if (mrst) 910 *topt++ = mrst; 911 912 #ifdef CONFIG_TCP_MD5SIG 913 if (key) { 914 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 915 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG); 916 tcp_v6_md5_hash_hdr((__u8 *)topt, key, 917 &ipv6_hdr(skb)->saddr, 918 &ipv6_hdr(skb)->daddr, t1); 919 } 920 #endif 921 922 memset(&fl6, 0, sizeof(fl6)); 923 fl6.daddr = ipv6_hdr(skb)->saddr; 924 fl6.saddr = ipv6_hdr(skb)->daddr; 925 fl6.flowlabel = label; 926 927 buff->ip_summed = CHECKSUM_PARTIAL; 928 929 __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr); 930 931 fl6.flowi6_proto = IPPROTO_TCP; 932 if (rt6_need_strict(&fl6.daddr) && !oif) 933 fl6.flowi6_oif = tcp_v6_iif(skb); 934 else { 935 if (!oif && netif_index_is_l3_master(net, skb->skb_iif)) 936 oif = skb->skb_iif; 937 938 fl6.flowi6_oif = oif; 939 } 940 941 if (sk) { 942 if (sk->sk_state == TCP_TIME_WAIT) 943 mark = inet_twsk(sk)->tw_mark; 944 else 945 mark = sk->sk_mark; 946 skb_set_delivery_time(buff, tcp_transmit_time(sk), true); 947 } 948 if (txhash) { 949 /* autoflowlabel/skb_get_hash_flowi6 rely on buff->hash */ 950 skb_set_hash(buff, txhash, PKT_HASH_TYPE_L4); 951 } 952 fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark) ?: mark; 953 fl6.fl6_dport = t1->dest; 954 fl6.fl6_sport = t1->source; 955 fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL); 956 security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6)); 957 958 /* Pass a socket to ip6_dst_lookup either it is for RST 959 * Underlying function will use this to retrieve the network 960 * namespace 961 */ 962 if (sk && sk->sk_state != TCP_TIME_WAIT) 963 dst = ip6_dst_lookup_flow(net, sk, &fl6, NULL); /*sk's xfrm_policy can be referred*/ 964 else 965 dst = ip6_dst_lookup_flow(net, ctl_sk, &fl6, NULL); 966 if (!IS_ERR(dst)) { 967 skb_dst_set(buff, dst); 968 ip6_xmit(ctl_sk, buff, &fl6, fl6.flowi6_mark, NULL, 969 tclass & ~INET_ECN_MASK, priority); 970 TCP_INC_STATS(net, TCP_MIB_OUTSEGS); 971 if (rst) 972 TCP_INC_STATS(net, TCP_MIB_OUTRSTS); 973 return; 974 } 975 976 kfree_skb(buff); 977 } 978 979 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) 980 { 981 const struct tcphdr *th = tcp_hdr(skb); 982 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 983 u32 seq = 0, ack_seq = 0; 984 struct tcp_md5sig_key *key = NULL; 985 #ifdef CONFIG_TCP_MD5SIG 986 const __u8 *hash_location = NULL; 987 unsigned char newhash[16]; 988 int genhash; 989 struct sock *sk1 = NULL; 990 #endif 991 __be32 label = 0; 992 u32 priority = 0; 993 struct net *net; 994 u32 txhash = 0; 995 int oif = 0; 996 997 if (th->rst) 998 return; 999 1000 /* If sk not NULL, it means we did a successful lookup and incoming 1001 * route had to be correct. prequeue might have dropped our dst. 1002 */ 1003 if (!sk && !ipv6_unicast_destination(skb)) 1004 return; 1005 1006 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); 1007 #ifdef CONFIG_TCP_MD5SIG 1008 rcu_read_lock(); 1009 hash_location = tcp_parse_md5sig_option(th); 1010 if (sk && sk_fullsock(sk)) { 1011 int l3index; 1012 1013 /* sdif set, means packet ingressed via a device 1014 * in an L3 domain and inet_iif is set to it. 1015 */ 1016 l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0; 1017 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index); 1018 } else if (hash_location) { 1019 int dif = tcp_v6_iif_l3_slave(skb); 1020 int sdif = tcp_v6_sdif(skb); 1021 int l3index; 1022 1023 /* 1024 * active side is lost. Try to find listening socket through 1025 * source port, and then find md5 key through listening socket. 1026 * we are not loose security here: 1027 * Incoming packet is checked with md5 hash with finding key, 1028 * no RST generated if md5 hash doesn't match. 1029 */ 1030 sk1 = inet6_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo, 1031 NULL, 0, &ipv6h->saddr, th->source, 1032 &ipv6h->daddr, ntohs(th->source), 1033 dif, sdif); 1034 if (!sk1) 1035 goto out; 1036 1037 /* sdif set, means packet ingressed via a device 1038 * in an L3 domain and dif is set to it. 1039 */ 1040 l3index = tcp_v6_sdif(skb) ? dif : 0; 1041 1042 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index); 1043 if (!key) 1044 goto out; 1045 1046 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb); 1047 if (genhash || memcmp(hash_location, newhash, 16) != 0) 1048 goto out; 1049 } 1050 #endif 1051 1052 if (th->ack) 1053 seq = ntohl(th->ack_seq); 1054 else 1055 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len - 1056 (th->doff << 2); 1057 1058 if (sk) { 1059 oif = sk->sk_bound_dev_if; 1060 if (sk_fullsock(sk)) { 1061 const struct ipv6_pinfo *np = tcp_inet6_sk(sk); 1062 1063 trace_tcp_send_reset(sk, skb); 1064 if (np->repflow) 1065 label = ip6_flowlabel(ipv6h); 1066 priority = sk->sk_priority; 1067 txhash = sk->sk_hash; 1068 } 1069 if (sk->sk_state == TCP_TIME_WAIT) { 1070 label = cpu_to_be32(inet_twsk(sk)->tw_flowlabel); 1071 priority = inet_twsk(sk)->tw_priority; 1072 txhash = inet_twsk(sk)->tw_txhash; 1073 } 1074 } else { 1075 if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_TCP_RESET) 1076 label = ip6_flowlabel(ipv6h); 1077 } 1078 1079 tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 1080 ipv6_get_dsfield(ipv6h), label, priority, txhash); 1081 1082 #ifdef CONFIG_TCP_MD5SIG 1083 out: 1084 rcu_read_unlock(); 1085 #endif 1086 } 1087 1088 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq, 1089 u32 ack, u32 win, u32 tsval, u32 tsecr, int oif, 1090 struct tcp_md5sig_key *key, u8 tclass, 1091 __be32 label, u32 priority, u32 txhash) 1092 { 1093 tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0, 1094 tclass, label, priority, txhash); 1095 } 1096 1097 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb) 1098 { 1099 struct inet_timewait_sock *tw = inet_twsk(sk); 1100 struct tcp_timewait_sock *tcptw = tcp_twsk(sk); 1101 1102 tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, 1103 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, 1104 tcp_time_stamp_raw() + tcptw->tw_ts_offset, 1105 tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw), 1106 tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority, 1107 tw->tw_txhash); 1108 1109 inet_twsk_put(tw); 1110 } 1111 1112 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, 1113 struct request_sock *req) 1114 { 1115 int l3index; 1116 1117 l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0; 1118 1119 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV 1120 * sk->sk_state == TCP_SYN_RECV -> for Fast Open. 1121 */ 1122 /* RFC 7323 2.3 1123 * The window field (SEG.WND) of every outgoing segment, with the 1124 * exception of <SYN> segments, MUST be right-shifted by 1125 * Rcv.Wind.Shift bits: 1126 */ 1127 tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ? 1128 tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt, 1129 tcp_rsk(req)->rcv_nxt, 1130 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale, 1131 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off, 1132 req->ts_recent, sk->sk_bound_dev_if, 1133 tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr, l3index), 1134 ipv6_get_dsfield(ipv6_hdr(skb)), 0, sk->sk_priority, 1135 tcp_rsk(req)->txhash); 1136 } 1137 1138 1139 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb) 1140 { 1141 #ifdef CONFIG_SYN_COOKIES 1142 const struct tcphdr *th = tcp_hdr(skb); 1143 1144 if (!th->syn) 1145 sk = cookie_v6_check(sk, skb); 1146 #endif 1147 return sk; 1148 } 1149 1150 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, 1151 struct tcphdr *th, u32 *cookie) 1152 { 1153 u16 mss = 0; 1154 #ifdef CONFIG_SYN_COOKIES 1155 mss = tcp_get_syncookie_mss(&tcp6_request_sock_ops, 1156 &tcp_request_sock_ipv6_ops, sk, th); 1157 if (mss) { 1158 *cookie = __cookie_v6_init_sequence(iph, th, &mss); 1159 tcp_synq_overflow(sk); 1160 } 1161 #endif 1162 return mss; 1163 } 1164 1165 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) 1166 { 1167 if (skb->protocol == htons(ETH_P_IP)) 1168 return tcp_v4_conn_request(sk, skb); 1169 1170 if (!ipv6_unicast_destination(skb)) 1171 goto drop; 1172 1173 if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) { 1174 __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS); 1175 return 0; 1176 } 1177 1178 return tcp_conn_request(&tcp6_request_sock_ops, 1179 &tcp_request_sock_ipv6_ops, sk, skb); 1180 1181 drop: 1182 tcp_listendrop(sk); 1183 return 0; /* don't send reset */ 1184 } 1185 1186 static void tcp_v6_restore_cb(struct sk_buff *skb) 1187 { 1188 /* We need to move header back to the beginning if xfrm6_policy_check() 1189 * and tcp_v6_fill_cb() are going to be called again. 1190 * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there. 1191 */ 1192 memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6, 1193 sizeof(struct inet6_skb_parm)); 1194 } 1195 1196 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 1197 struct request_sock *req, 1198 struct dst_entry *dst, 1199 struct request_sock *req_unhash, 1200 bool *own_req) 1201 { 1202 struct inet_request_sock *ireq; 1203 struct ipv6_pinfo *newnp; 1204 const struct ipv6_pinfo *np = tcp_inet6_sk(sk); 1205 struct ipv6_txoptions *opt; 1206 struct inet_sock *newinet; 1207 bool found_dup_sk = false; 1208 struct tcp_sock *newtp; 1209 struct sock *newsk; 1210 #ifdef CONFIG_TCP_MD5SIG 1211 struct tcp_md5sig_key *key; 1212 int l3index; 1213 #endif 1214 struct flowi6 fl6; 1215 1216 if (skb->protocol == htons(ETH_P_IP)) { 1217 /* 1218 * v6 mapped 1219 */ 1220 1221 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst, 1222 req_unhash, own_req); 1223 1224 if (!newsk) 1225 return NULL; 1226 1227 inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk); 1228 1229 newnp = tcp_inet6_sk(newsk); 1230 newtp = tcp_sk(newsk); 1231 1232 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 1233 1234 newnp->saddr = newsk->sk_v6_rcv_saddr; 1235 1236 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped; 1237 if (sk_is_mptcp(newsk)) 1238 mptcpv6_handle_mapped(newsk, true); 1239 newsk->sk_backlog_rcv = tcp_v4_do_rcv; 1240 #ifdef CONFIG_TCP_MD5SIG 1241 newtp->af_specific = &tcp_sock_ipv6_mapped_specific; 1242 #endif 1243 1244 newnp->ipv6_mc_list = NULL; 1245 newnp->ipv6_ac_list = NULL; 1246 newnp->ipv6_fl_list = NULL; 1247 newnp->pktoptions = NULL; 1248 newnp->opt = NULL; 1249 newnp->mcast_oif = inet_iif(skb); 1250 newnp->mcast_hops = ip_hdr(skb)->ttl; 1251 newnp->rcv_flowinfo = 0; 1252 if (np->repflow) 1253 newnp->flow_label = 0; 1254 1255 /* 1256 * No need to charge this sock to the relevant IPv6 refcnt debug socks count 1257 * here, tcp_create_openreq_child now does this for us, see the comment in 1258 * that function for the gory details. -acme 1259 */ 1260 1261 /* It is tricky place. Until this moment IPv4 tcp 1262 worked with IPv6 icsk.icsk_af_ops. 1263 Sync it now. 1264 */ 1265 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie); 1266 1267 return newsk; 1268 } 1269 1270 ireq = inet_rsk(req); 1271 1272 if (sk_acceptq_is_full(sk)) 1273 goto out_overflow; 1274 1275 if (!dst) { 1276 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP); 1277 if (!dst) 1278 goto out; 1279 } 1280 1281 newsk = tcp_create_openreq_child(sk, req, skb); 1282 if (!newsk) 1283 goto out_nonewsk; 1284 1285 /* 1286 * No need to charge this sock to the relevant IPv6 refcnt debug socks 1287 * count here, tcp_create_openreq_child now does this for us, see the 1288 * comment in that function for the gory details. -acme 1289 */ 1290 1291 newsk->sk_gso_type = SKB_GSO_TCPV6; 1292 ip6_dst_store(newsk, dst, NULL, NULL); 1293 inet6_sk_rx_dst_set(newsk, skb); 1294 1295 inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk); 1296 1297 newtp = tcp_sk(newsk); 1298 newinet = inet_sk(newsk); 1299 newnp = tcp_inet6_sk(newsk); 1300 1301 memcpy(newnp, np, sizeof(struct ipv6_pinfo)); 1302 1303 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr; 1304 newnp->saddr = ireq->ir_v6_loc_addr; 1305 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; 1306 newsk->sk_bound_dev_if = ireq->ir_iif; 1307 1308 /* Now IPv6 options... 1309 1310 First: no IPv4 options. 1311 */ 1312 newinet->inet_opt = NULL; 1313 newnp->ipv6_mc_list = NULL; 1314 newnp->ipv6_ac_list = NULL; 1315 newnp->ipv6_fl_list = NULL; 1316 1317 /* Clone RX bits */ 1318 newnp->rxopt.all = np->rxopt.all; 1319 1320 newnp->pktoptions = NULL; 1321 newnp->opt = NULL; 1322 newnp->mcast_oif = tcp_v6_iif(skb); 1323 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; 1324 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb)); 1325 if (np->repflow) 1326 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb)); 1327 1328 /* Set ToS of the new socket based upon the value of incoming SYN. 1329 * ECT bits are set later in tcp_init_transfer(). 1330 */ 1331 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)) 1332 newnp->tclass = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK; 1333 1334 /* Clone native IPv6 options from listening socket (if any) 1335 1336 Yes, keeping reference count would be much more clever, 1337 but we make one more one thing there: reattach optmem 1338 to newsk. 1339 */ 1340 opt = ireq->ipv6_opt; 1341 if (!opt) 1342 opt = rcu_dereference(np->opt); 1343 if (opt) { 1344 opt = ipv6_dup_options(newsk, opt); 1345 RCU_INIT_POINTER(newnp->opt, opt); 1346 } 1347 inet_csk(newsk)->icsk_ext_hdr_len = 0; 1348 if (opt) 1349 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen + 1350 opt->opt_flen; 1351 1352 tcp_ca_openreq_child(newsk, dst); 1353 1354 tcp_sync_mss(newsk, dst_mtu(dst)); 1355 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst)); 1356 1357 tcp_initialize_rcv_mss(newsk); 1358 1359 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; 1360 newinet->inet_rcv_saddr = LOOPBACK4_IPV6; 1361 1362 #ifdef CONFIG_TCP_MD5SIG 1363 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif); 1364 1365 /* Copy over the MD5 key from the original socket */ 1366 key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr, l3index); 1367 if (key) { 1368 /* We're using one, so create a matching key 1369 * on the newsk structure. If we fail to get 1370 * memory, then we end up not copying the key 1371 * across. Shucks. 1372 */ 1373 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr, 1374 AF_INET6, 128, l3index, key->flags, key->key, key->keylen, 1375 sk_gfp_mask(sk, GFP_ATOMIC)); 1376 } 1377 #endif 1378 1379 if (__inet_inherit_port(sk, newsk) < 0) { 1380 inet_csk_prepare_forced_close(newsk); 1381 tcp_done(newsk); 1382 goto out; 1383 } 1384 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), 1385 &found_dup_sk); 1386 if (*own_req) { 1387 tcp_move_syn(newtp, req); 1388 1389 /* Clone pktoptions received with SYN, if we own the req */ 1390 if (ireq->pktopts) { 1391 newnp->pktoptions = skb_clone(ireq->pktopts, 1392 sk_gfp_mask(sk, GFP_ATOMIC)); 1393 consume_skb(ireq->pktopts); 1394 ireq->pktopts = NULL; 1395 if (newnp->pktoptions) { 1396 tcp_v6_restore_cb(newnp->pktoptions); 1397 skb_set_owner_r(newnp->pktoptions, newsk); 1398 } 1399 } 1400 } else { 1401 if (!req_unhash && found_dup_sk) { 1402 /* This code path should only be executed in the 1403 * syncookie case only 1404 */ 1405 bh_unlock_sock(newsk); 1406 sock_put(newsk); 1407 newsk = NULL; 1408 } 1409 } 1410 1411 return newsk; 1412 1413 out_overflow: 1414 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 1415 out_nonewsk: 1416 dst_release(dst); 1417 out: 1418 tcp_listendrop(sk); 1419 return NULL; 1420 } 1421 1422 INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *, 1423 u32)); 1424 /* The socket must have it's spinlock held when we get 1425 * here, unless it is a TCP_LISTEN socket. 1426 * 1427 * We have a potential double-lock case here, so even when 1428 * doing backlog processing we use the BH locking scheme. 1429 * This is because we cannot sleep with the original spinlock 1430 * held. 1431 */ 1432 INDIRECT_CALLABLE_SCOPE 1433 int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) 1434 { 1435 struct ipv6_pinfo *np = tcp_inet6_sk(sk); 1436 struct sk_buff *opt_skb = NULL; 1437 enum skb_drop_reason reason; 1438 struct tcp_sock *tp; 1439 1440 /* Imagine: socket is IPv6. IPv4 packet arrives, 1441 goes to IPv4 receive handler and backlogged. 1442 From backlog it always goes here. Kerboom... 1443 Fortunately, tcp_rcv_established and rcv_established 1444 handle them correctly, but it is not case with 1445 tcp_v6_hnd_req and tcp_v6_send_reset(). --ANK 1446 */ 1447 1448 if (skb->protocol == htons(ETH_P_IP)) 1449 return tcp_v4_do_rcv(sk, skb); 1450 1451 /* 1452 * socket locking is here for SMP purposes as backlog rcv 1453 * is currently called with bh processing disabled. 1454 */ 1455 1456 /* Do Stevens' IPV6_PKTOPTIONS. 1457 1458 Yes, guys, it is the only place in our code, where we 1459 may make it not affecting IPv4. 1460 The rest of code is protocol independent, 1461 and I do not like idea to uglify IPv4. 1462 1463 Actually, all the idea behind IPV6_PKTOPTIONS 1464 looks not very well thought. For now we latch 1465 options, received in the last packet, enqueued 1466 by tcp. Feel free to propose better solution. 1467 --ANK (980728) 1468 */ 1469 if (np->rxopt.all) 1470 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC)); 1471 1472 reason = SKB_DROP_REASON_NOT_SPECIFIED; 1473 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ 1474 struct dst_entry *dst; 1475 1476 dst = rcu_dereference_protected(sk->sk_rx_dst, 1477 lockdep_sock_is_held(sk)); 1478 1479 sock_rps_save_rxhash(sk, skb); 1480 sk_mark_napi_id(sk, skb); 1481 if (dst) { 1482 if (sk->sk_rx_dst_ifindex != skb->skb_iif || 1483 INDIRECT_CALL_1(dst->ops->check, ip6_dst_check, 1484 dst, sk->sk_rx_dst_cookie) == NULL) { 1485 RCU_INIT_POINTER(sk->sk_rx_dst, NULL); 1486 dst_release(dst); 1487 } 1488 } 1489 1490 tcp_rcv_established(sk, skb); 1491 if (opt_skb) 1492 goto ipv6_pktoptions; 1493 return 0; 1494 } 1495 1496 if (tcp_checksum_complete(skb)) 1497 goto csum_err; 1498 1499 if (sk->sk_state == TCP_LISTEN) { 1500 struct sock *nsk = tcp_v6_cookie_check(sk, skb); 1501 1502 if (!nsk) 1503 goto discard; 1504 1505 if (nsk != sk) { 1506 if (tcp_child_process(sk, nsk, skb)) 1507 goto reset; 1508 if (opt_skb) 1509 __kfree_skb(opt_skb); 1510 return 0; 1511 } 1512 } else 1513 sock_rps_save_rxhash(sk, skb); 1514 1515 if (tcp_rcv_state_process(sk, skb)) 1516 goto reset; 1517 if (opt_skb) 1518 goto ipv6_pktoptions; 1519 return 0; 1520 1521 reset: 1522 tcp_v6_send_reset(sk, skb); 1523 discard: 1524 if (opt_skb) 1525 __kfree_skb(opt_skb); 1526 kfree_skb_reason(skb, reason); 1527 return 0; 1528 csum_err: 1529 reason = SKB_DROP_REASON_TCP_CSUM; 1530 trace_tcp_bad_csum(skb); 1531 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); 1532 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); 1533 goto discard; 1534 1535 1536 ipv6_pktoptions: 1537 /* Do you ask, what is it? 1538 1539 1. skb was enqueued by tcp. 1540 2. skb is added to tail of read queue, rather than out of order. 1541 3. socket is not in passive state. 1542 4. Finally, it really contains options, which user wants to receive. 1543 */ 1544 tp = tcp_sk(sk); 1545 if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt && 1546 !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) { 1547 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo) 1548 np->mcast_oif = tcp_v6_iif(opt_skb); 1549 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) 1550 np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit; 1551 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass) 1552 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb)); 1553 if (np->repflow) 1554 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb)); 1555 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) { 1556 skb_set_owner_r(opt_skb, sk); 1557 tcp_v6_restore_cb(opt_skb); 1558 opt_skb = xchg(&np->pktoptions, opt_skb); 1559 } else { 1560 __kfree_skb(opt_skb); 1561 opt_skb = xchg(&np->pktoptions, NULL); 1562 } 1563 } 1564 1565 consume_skb(opt_skb); 1566 return 0; 1567 } 1568 1569 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr, 1570 const struct tcphdr *th) 1571 { 1572 /* This is tricky: we move IP6CB at its correct location into 1573 * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because 1574 * _decode_session6() uses IP6CB(). 1575 * barrier() makes sure compiler won't play aliasing games. 1576 */ 1577 memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb), 1578 sizeof(struct inet6_skb_parm)); 1579 barrier(); 1580 1581 TCP_SKB_CB(skb)->seq = ntohl(th->seq); 1582 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + 1583 skb->len - th->doff*4); 1584 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); 1585 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th); 1586 TCP_SKB_CB(skb)->tcp_tw_isn = 0; 1587 TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr); 1588 TCP_SKB_CB(skb)->sacked = 0; 1589 TCP_SKB_CB(skb)->has_rxtstamp = 1590 skb->tstamp || skb_hwtstamps(skb)->hwtstamp; 1591 } 1592 1593 INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) 1594 { 1595 enum skb_drop_reason drop_reason; 1596 int sdif = inet6_sdif(skb); 1597 int dif = inet6_iif(skb); 1598 const struct tcphdr *th; 1599 const struct ipv6hdr *hdr; 1600 bool refcounted; 1601 struct sock *sk; 1602 int ret; 1603 struct net *net = dev_net(skb->dev); 1604 1605 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; 1606 if (skb->pkt_type != PACKET_HOST) 1607 goto discard_it; 1608 1609 /* 1610 * Count it even if it's bad. 1611 */ 1612 __TCP_INC_STATS(net, TCP_MIB_INSEGS); 1613 1614 if (!pskb_may_pull(skb, sizeof(struct tcphdr))) 1615 goto discard_it; 1616 1617 th = (const struct tcphdr *)skb->data; 1618 1619 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) { 1620 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL; 1621 goto bad_packet; 1622 } 1623 if (!pskb_may_pull(skb, th->doff*4)) 1624 goto discard_it; 1625 1626 if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo)) 1627 goto csum_error; 1628 1629 th = (const struct tcphdr *)skb->data; 1630 hdr = ipv6_hdr(skb); 1631 1632 lookup: 1633 sk = __inet6_lookup_skb(net->ipv4.tcp_death_row.hashinfo, skb, __tcp_hdrlen(th), 1634 th->source, th->dest, inet6_iif(skb), sdif, 1635 &refcounted); 1636 if (!sk) 1637 goto no_tcp_socket; 1638 1639 process: 1640 if (sk->sk_state == TCP_TIME_WAIT) 1641 goto do_time_wait; 1642 1643 if (sk->sk_state == TCP_NEW_SYN_RECV) { 1644 struct request_sock *req = inet_reqsk(sk); 1645 bool req_stolen = false; 1646 struct sock *nsk; 1647 1648 sk = req->rsk_listener; 1649 drop_reason = tcp_inbound_md5_hash(sk, skb, 1650 &hdr->saddr, &hdr->daddr, 1651 AF_INET6, dif, sdif); 1652 if (drop_reason) { 1653 sk_drops_add(sk, skb); 1654 reqsk_put(req); 1655 goto discard_it; 1656 } 1657 if (tcp_checksum_complete(skb)) { 1658 reqsk_put(req); 1659 goto csum_error; 1660 } 1661 if (unlikely(sk->sk_state != TCP_LISTEN)) { 1662 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb); 1663 if (!nsk) { 1664 inet_csk_reqsk_queue_drop_and_put(sk, req); 1665 goto lookup; 1666 } 1667 sk = nsk; 1668 /* reuseport_migrate_sock() has already held one sk_refcnt 1669 * before returning. 1670 */ 1671 } else { 1672 sock_hold(sk); 1673 } 1674 refcounted = true; 1675 nsk = NULL; 1676 if (!tcp_filter(sk, skb)) { 1677 th = (const struct tcphdr *)skb->data; 1678 hdr = ipv6_hdr(skb); 1679 tcp_v6_fill_cb(skb, hdr, th); 1680 nsk = tcp_check_req(sk, skb, req, false, &req_stolen); 1681 } else { 1682 drop_reason = SKB_DROP_REASON_SOCKET_FILTER; 1683 } 1684 if (!nsk) { 1685 reqsk_put(req); 1686 if (req_stolen) { 1687 /* Another cpu got exclusive access to req 1688 * and created a full blown socket. 1689 * Try to feed this packet to this socket 1690 * instead of discarding it. 1691 */ 1692 tcp_v6_restore_cb(skb); 1693 sock_put(sk); 1694 goto lookup; 1695 } 1696 goto discard_and_relse; 1697 } 1698 if (nsk == sk) { 1699 reqsk_put(req); 1700 tcp_v6_restore_cb(skb); 1701 } else if (tcp_child_process(sk, nsk, skb)) { 1702 tcp_v6_send_reset(nsk, skb); 1703 goto discard_and_relse; 1704 } else { 1705 sock_put(sk); 1706 return 0; 1707 } 1708 } 1709 1710 if (static_branch_unlikely(&ip6_min_hopcount)) { 1711 /* min_hopcount can be changed concurrently from do_ipv6_setsockopt() */ 1712 if (hdr->hop_limit < READ_ONCE(tcp_inet6_sk(sk)->min_hopcount)) { 1713 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); 1714 goto discard_and_relse; 1715 } 1716 } 1717 1718 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) { 1719 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 1720 goto discard_and_relse; 1721 } 1722 1723 drop_reason = tcp_inbound_md5_hash(sk, skb, &hdr->saddr, &hdr->daddr, 1724 AF_INET6, dif, sdif); 1725 if (drop_reason) 1726 goto discard_and_relse; 1727 1728 if (tcp_filter(sk, skb)) { 1729 drop_reason = SKB_DROP_REASON_SOCKET_FILTER; 1730 goto discard_and_relse; 1731 } 1732 th = (const struct tcphdr *)skb->data; 1733 hdr = ipv6_hdr(skb); 1734 tcp_v6_fill_cb(skb, hdr, th); 1735 1736 skb->dev = NULL; 1737 1738 if (sk->sk_state == TCP_LISTEN) { 1739 ret = tcp_v6_do_rcv(sk, skb); 1740 goto put_and_return; 1741 } 1742 1743 sk_incoming_cpu_update(sk); 1744 1745 bh_lock_sock_nested(sk); 1746 tcp_segs_in(tcp_sk(sk), skb); 1747 ret = 0; 1748 if (!sock_owned_by_user(sk)) { 1749 ret = tcp_v6_do_rcv(sk, skb); 1750 } else { 1751 if (tcp_add_backlog(sk, skb, &drop_reason)) 1752 goto discard_and_relse; 1753 } 1754 bh_unlock_sock(sk); 1755 put_and_return: 1756 if (refcounted) 1757 sock_put(sk); 1758 return ret ? -1 : 0; 1759 1760 no_tcp_socket: 1761 drop_reason = SKB_DROP_REASON_NO_SOCKET; 1762 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 1763 goto discard_it; 1764 1765 tcp_v6_fill_cb(skb, hdr, th); 1766 1767 if (tcp_checksum_complete(skb)) { 1768 csum_error: 1769 drop_reason = SKB_DROP_REASON_TCP_CSUM; 1770 trace_tcp_bad_csum(skb); 1771 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS); 1772 bad_packet: 1773 __TCP_INC_STATS(net, TCP_MIB_INERRS); 1774 } else { 1775 tcp_v6_send_reset(NULL, skb); 1776 } 1777 1778 discard_it: 1779 SKB_DR_OR(drop_reason, NOT_SPECIFIED); 1780 kfree_skb_reason(skb, drop_reason); 1781 return 0; 1782 1783 discard_and_relse: 1784 sk_drops_add(sk, skb); 1785 if (refcounted) 1786 sock_put(sk); 1787 goto discard_it; 1788 1789 do_time_wait: 1790 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 1791 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 1792 inet_twsk_put(inet_twsk(sk)); 1793 goto discard_it; 1794 } 1795 1796 tcp_v6_fill_cb(skb, hdr, th); 1797 1798 if (tcp_checksum_complete(skb)) { 1799 inet_twsk_put(inet_twsk(sk)); 1800 goto csum_error; 1801 } 1802 1803 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) { 1804 case TCP_TW_SYN: 1805 { 1806 struct sock *sk2; 1807 1808 sk2 = inet6_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo, 1809 skb, __tcp_hdrlen(th), 1810 &ipv6_hdr(skb)->saddr, th->source, 1811 &ipv6_hdr(skb)->daddr, 1812 ntohs(th->dest), 1813 tcp_v6_iif_l3_slave(skb), 1814 sdif); 1815 if (sk2) { 1816 struct inet_timewait_sock *tw = inet_twsk(sk); 1817 inet_twsk_deschedule_put(tw); 1818 sk = sk2; 1819 tcp_v6_restore_cb(skb); 1820 refcounted = false; 1821 goto process; 1822 } 1823 } 1824 /* to ACK */ 1825 fallthrough; 1826 case TCP_TW_ACK: 1827 tcp_v6_timewait_ack(sk, skb); 1828 break; 1829 case TCP_TW_RST: 1830 tcp_v6_send_reset(sk, skb); 1831 inet_twsk_deschedule_put(inet_twsk(sk)); 1832 goto discard_it; 1833 case TCP_TW_SUCCESS: 1834 ; 1835 } 1836 goto discard_it; 1837 } 1838 1839 void tcp_v6_early_demux(struct sk_buff *skb) 1840 { 1841 struct net *net = dev_net(skb->dev); 1842 const struct ipv6hdr *hdr; 1843 const struct tcphdr *th; 1844 struct sock *sk; 1845 1846 if (skb->pkt_type != PACKET_HOST) 1847 return; 1848 1849 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr))) 1850 return; 1851 1852 hdr = ipv6_hdr(skb); 1853 th = tcp_hdr(skb); 1854 1855 if (th->doff < sizeof(struct tcphdr) / 4) 1856 return; 1857 1858 /* Note : We use inet6_iif() here, not tcp_v6_iif() */ 1859 sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, 1860 &hdr->saddr, th->source, 1861 &hdr->daddr, ntohs(th->dest), 1862 inet6_iif(skb), inet6_sdif(skb)); 1863 if (sk) { 1864 skb->sk = sk; 1865 skb->destructor = sock_edemux; 1866 if (sk_fullsock(sk)) { 1867 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst); 1868 1869 if (dst) 1870 dst = dst_check(dst, sk->sk_rx_dst_cookie); 1871 if (dst && 1872 sk->sk_rx_dst_ifindex == skb->skb_iif) 1873 skb_dst_set_noref(skb, dst); 1874 } 1875 } 1876 } 1877 1878 static struct timewait_sock_ops tcp6_timewait_sock_ops = { 1879 .twsk_obj_size = sizeof(struct tcp6_timewait_sock), 1880 .twsk_unique = tcp_twsk_unique, 1881 .twsk_destructor = tcp_twsk_destructor, 1882 }; 1883 1884 INDIRECT_CALLABLE_SCOPE void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb) 1885 { 1886 __tcp_v6_send_check(skb, &sk->sk_v6_rcv_saddr, &sk->sk_v6_daddr); 1887 } 1888 1889 const struct inet_connection_sock_af_ops ipv6_specific = { 1890 .queue_xmit = inet6_csk_xmit, 1891 .send_check = tcp_v6_send_check, 1892 .rebuild_header = inet6_sk_rebuild_header, 1893 .sk_rx_dst_set = inet6_sk_rx_dst_set, 1894 .conn_request = tcp_v6_conn_request, 1895 .syn_recv_sock = tcp_v6_syn_recv_sock, 1896 .net_header_len = sizeof(struct ipv6hdr), 1897 .net_frag_header_len = sizeof(struct frag_hdr), 1898 .setsockopt = ipv6_setsockopt, 1899 .getsockopt = ipv6_getsockopt, 1900 .addr2sockaddr = inet6_csk_addr2sockaddr, 1901 .sockaddr_len = sizeof(struct sockaddr_in6), 1902 .mtu_reduced = tcp_v6_mtu_reduced, 1903 }; 1904 1905 #ifdef CONFIG_TCP_MD5SIG 1906 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = { 1907 .md5_lookup = tcp_v6_md5_lookup, 1908 .calc_md5_hash = tcp_v6_md5_hash_skb, 1909 .md5_parse = tcp_v6_parse_md5_keys, 1910 }; 1911 #endif 1912 1913 /* 1914 * TCP over IPv4 via INET6 API 1915 */ 1916 static const struct inet_connection_sock_af_ops ipv6_mapped = { 1917 .queue_xmit = ip_queue_xmit, 1918 .send_check = tcp_v4_send_check, 1919 .rebuild_header = inet_sk_rebuild_header, 1920 .sk_rx_dst_set = inet_sk_rx_dst_set, 1921 .conn_request = tcp_v6_conn_request, 1922 .syn_recv_sock = tcp_v6_syn_recv_sock, 1923 .net_header_len = sizeof(struct iphdr), 1924 .setsockopt = ipv6_setsockopt, 1925 .getsockopt = ipv6_getsockopt, 1926 .addr2sockaddr = inet6_csk_addr2sockaddr, 1927 .sockaddr_len = sizeof(struct sockaddr_in6), 1928 .mtu_reduced = tcp_v4_mtu_reduced, 1929 }; 1930 1931 #ifdef CONFIG_TCP_MD5SIG 1932 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = { 1933 .md5_lookup = tcp_v4_md5_lookup, 1934 .calc_md5_hash = tcp_v4_md5_hash_skb, 1935 .md5_parse = tcp_v6_parse_md5_keys, 1936 }; 1937 #endif 1938 1939 /* NOTE: A lot of things set to zero explicitly by call to 1940 * sk_alloc() so need not be done here. 1941 */ 1942 static int tcp_v6_init_sock(struct sock *sk) 1943 { 1944 struct inet_connection_sock *icsk = inet_csk(sk); 1945 1946 tcp_init_sock(sk); 1947 1948 icsk->icsk_af_ops = &ipv6_specific; 1949 1950 #ifdef CONFIG_TCP_MD5SIG 1951 tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific; 1952 #endif 1953 1954 return 0; 1955 } 1956 1957 #ifdef CONFIG_PROC_FS 1958 /* Proc filesystem TCPv6 sock list dumping. */ 1959 static void get_openreq6(struct seq_file *seq, 1960 const struct request_sock *req, int i) 1961 { 1962 long ttd = req->rsk_timer.expires - jiffies; 1963 const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr; 1964 const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr; 1965 1966 if (ttd < 0) 1967 ttd = 0; 1968 1969 seq_printf(seq, 1970 "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X " 1971 "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n", 1972 i, 1973 src->s6_addr32[0], src->s6_addr32[1], 1974 src->s6_addr32[2], src->s6_addr32[3], 1975 inet_rsk(req)->ir_num, 1976 dest->s6_addr32[0], dest->s6_addr32[1], 1977 dest->s6_addr32[2], dest->s6_addr32[3], 1978 ntohs(inet_rsk(req)->ir_rmt_port), 1979 TCP_SYN_RECV, 1980 0, 0, /* could print option size, but that is af dependent. */ 1981 1, /* timers active (only the expire timer) */ 1982 jiffies_to_clock_t(ttd), 1983 req->num_timeout, 1984 from_kuid_munged(seq_user_ns(seq), 1985 sock_i_uid(req->rsk_listener)), 1986 0, /* non standard timer */ 1987 0, /* open_requests have no inode */ 1988 0, req); 1989 } 1990 1991 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i) 1992 { 1993 const struct in6_addr *dest, *src; 1994 __u16 destp, srcp; 1995 int timer_active; 1996 unsigned long timer_expires; 1997 const struct inet_sock *inet = inet_sk(sp); 1998 const struct tcp_sock *tp = tcp_sk(sp); 1999 const struct inet_connection_sock *icsk = inet_csk(sp); 2000 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq; 2001 int rx_queue; 2002 int state; 2003 2004 dest = &sp->sk_v6_daddr; 2005 src = &sp->sk_v6_rcv_saddr; 2006 destp = ntohs(inet->inet_dport); 2007 srcp = ntohs(inet->inet_sport); 2008 2009 if (icsk->icsk_pending == ICSK_TIME_RETRANS || 2010 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT || 2011 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { 2012 timer_active = 1; 2013 timer_expires = icsk->icsk_timeout; 2014 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { 2015 timer_active = 4; 2016 timer_expires = icsk->icsk_timeout; 2017 } else if (timer_pending(&sp->sk_timer)) { 2018 timer_active = 2; 2019 timer_expires = sp->sk_timer.expires; 2020 } else { 2021 timer_active = 0; 2022 timer_expires = jiffies; 2023 } 2024 2025 state = inet_sk_state_load(sp); 2026 if (state == TCP_LISTEN) 2027 rx_queue = READ_ONCE(sp->sk_ack_backlog); 2028 else 2029 /* Because we don't lock the socket, 2030 * we might find a transient negative value. 2031 */ 2032 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) - 2033 READ_ONCE(tp->copied_seq), 0); 2034 2035 seq_printf(seq, 2036 "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X " 2037 "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n", 2038 i, 2039 src->s6_addr32[0], src->s6_addr32[1], 2040 src->s6_addr32[2], src->s6_addr32[3], srcp, 2041 dest->s6_addr32[0], dest->s6_addr32[1], 2042 dest->s6_addr32[2], dest->s6_addr32[3], destp, 2043 state, 2044 READ_ONCE(tp->write_seq) - tp->snd_una, 2045 rx_queue, 2046 timer_active, 2047 jiffies_delta_to_clock_t(timer_expires - jiffies), 2048 icsk->icsk_retransmits, 2049 from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)), 2050 icsk->icsk_probes_out, 2051 sock_i_ino(sp), 2052 refcount_read(&sp->sk_refcnt), sp, 2053 jiffies_to_clock_t(icsk->icsk_rto), 2054 jiffies_to_clock_t(icsk->icsk_ack.ato), 2055 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sp), 2056 tcp_snd_cwnd(tp), 2057 state == TCP_LISTEN ? 2058 fastopenq->max_qlen : 2059 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh) 2060 ); 2061 } 2062 2063 static void get_timewait6_sock(struct seq_file *seq, 2064 struct inet_timewait_sock *tw, int i) 2065 { 2066 long delta = tw->tw_timer.expires - jiffies; 2067 const struct in6_addr *dest, *src; 2068 __u16 destp, srcp; 2069 2070 dest = &tw->tw_v6_daddr; 2071 src = &tw->tw_v6_rcv_saddr; 2072 destp = ntohs(tw->tw_dport); 2073 srcp = ntohs(tw->tw_sport); 2074 2075 seq_printf(seq, 2076 "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X " 2077 "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n", 2078 i, 2079 src->s6_addr32[0], src->s6_addr32[1], 2080 src->s6_addr32[2], src->s6_addr32[3], srcp, 2081 dest->s6_addr32[0], dest->s6_addr32[1], 2082 dest->s6_addr32[2], dest->s6_addr32[3], destp, 2083 tw->tw_substate, 0, 0, 2084 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, 2085 refcount_read(&tw->tw_refcnt), tw); 2086 } 2087 2088 static int tcp6_seq_show(struct seq_file *seq, void *v) 2089 { 2090 struct tcp_iter_state *st; 2091 struct sock *sk = v; 2092 2093 if (v == SEQ_START_TOKEN) { 2094 seq_puts(seq, 2095 " sl " 2096 "local_address " 2097 "remote_address " 2098 "st tx_queue rx_queue tr tm->when retrnsmt" 2099 " uid timeout inode\n"); 2100 goto out; 2101 } 2102 st = seq->private; 2103 2104 if (sk->sk_state == TCP_TIME_WAIT) 2105 get_timewait6_sock(seq, v, st->num); 2106 else if (sk->sk_state == TCP_NEW_SYN_RECV) 2107 get_openreq6(seq, v, st->num); 2108 else 2109 get_tcp6_sock(seq, v, st->num); 2110 out: 2111 return 0; 2112 } 2113 2114 static const struct seq_operations tcp6_seq_ops = { 2115 .show = tcp6_seq_show, 2116 .start = tcp_seq_start, 2117 .next = tcp_seq_next, 2118 .stop = tcp_seq_stop, 2119 }; 2120 2121 static struct tcp_seq_afinfo tcp6_seq_afinfo = { 2122 .family = AF_INET6, 2123 }; 2124 2125 int __net_init tcp6_proc_init(struct net *net) 2126 { 2127 if (!proc_create_net_data("tcp6", 0444, net->proc_net, &tcp6_seq_ops, 2128 sizeof(struct tcp_iter_state), &tcp6_seq_afinfo)) 2129 return -ENOMEM; 2130 return 0; 2131 } 2132 2133 void tcp6_proc_exit(struct net *net) 2134 { 2135 remove_proc_entry("tcp6", net->proc_net); 2136 } 2137 #endif 2138 2139 struct proto tcpv6_prot = { 2140 .name = "TCPv6", 2141 .owner = THIS_MODULE, 2142 .close = tcp_close, 2143 .pre_connect = tcp_v6_pre_connect, 2144 .connect = tcp_v6_connect, 2145 .disconnect = tcp_disconnect, 2146 .accept = inet_csk_accept, 2147 .ioctl = tcp_ioctl, 2148 .init = tcp_v6_init_sock, 2149 .destroy = tcp_v4_destroy_sock, 2150 .shutdown = tcp_shutdown, 2151 .setsockopt = tcp_setsockopt, 2152 .getsockopt = tcp_getsockopt, 2153 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt, 2154 .keepalive = tcp_set_keepalive, 2155 .recvmsg = tcp_recvmsg, 2156 .sendmsg = tcp_sendmsg, 2157 .sendpage = tcp_sendpage, 2158 .backlog_rcv = tcp_v6_do_rcv, 2159 .release_cb = tcp_release_cb, 2160 .hash = inet6_hash, 2161 .unhash = inet_unhash, 2162 .get_port = inet_csk_get_port, 2163 .put_port = inet_put_port, 2164 #ifdef CONFIG_BPF_SYSCALL 2165 .psock_update_sk_prot = tcp_bpf_update_proto, 2166 #endif 2167 .enter_memory_pressure = tcp_enter_memory_pressure, 2168 .leave_memory_pressure = tcp_leave_memory_pressure, 2169 .stream_memory_free = tcp_stream_memory_free, 2170 .sockets_allocated = &tcp_sockets_allocated, 2171 2172 .memory_allocated = &tcp_memory_allocated, 2173 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc, 2174 2175 .memory_pressure = &tcp_memory_pressure, 2176 .orphan_count = &tcp_orphan_count, 2177 .sysctl_mem = sysctl_tcp_mem, 2178 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 2179 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), 2180 .max_header = MAX_TCP_HEADER, 2181 .obj_size = sizeof(struct tcp6_sock), 2182 .slab_flags = SLAB_TYPESAFE_BY_RCU, 2183 .twsk_prot = &tcp6_timewait_sock_ops, 2184 .rsk_prot = &tcp6_request_sock_ops, 2185 .h.hashinfo = NULL, 2186 .no_autobind = true, 2187 .diag_destroy = tcp_abort, 2188 }; 2189 EXPORT_SYMBOL_GPL(tcpv6_prot); 2190 2191 static const struct inet6_protocol tcpv6_protocol = { 2192 .handler = tcp_v6_rcv, 2193 .err_handler = tcp_v6_err, 2194 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, 2195 }; 2196 2197 static struct inet_protosw tcpv6_protosw = { 2198 .type = SOCK_STREAM, 2199 .protocol = IPPROTO_TCP, 2200 .prot = &tcpv6_prot, 2201 .ops = &inet6_stream_ops, 2202 .flags = INET_PROTOSW_PERMANENT | 2203 INET_PROTOSW_ICSK, 2204 }; 2205 2206 static int __net_init tcpv6_net_init(struct net *net) 2207 { 2208 return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6, 2209 SOCK_RAW, IPPROTO_TCP, net); 2210 } 2211 2212 static void __net_exit tcpv6_net_exit(struct net *net) 2213 { 2214 inet_ctl_sock_destroy(net->ipv6.tcp_sk); 2215 } 2216 2217 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list) 2218 { 2219 tcp_twsk_purge(net_exit_list, AF_INET6); 2220 } 2221 2222 static struct pernet_operations tcpv6_net_ops = { 2223 .init = tcpv6_net_init, 2224 .exit = tcpv6_net_exit, 2225 .exit_batch = tcpv6_net_exit_batch, 2226 }; 2227 2228 int __init tcpv6_init(void) 2229 { 2230 int ret; 2231 2232 ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP); 2233 if (ret) 2234 goto out; 2235 2236 /* register inet6 protocol */ 2237 ret = inet6_register_protosw(&tcpv6_protosw); 2238 if (ret) 2239 goto out_tcpv6_protocol; 2240 2241 ret = register_pernet_subsys(&tcpv6_net_ops); 2242 if (ret) 2243 goto out_tcpv6_protosw; 2244 2245 ret = mptcpv6_init(); 2246 if (ret) 2247 goto out_tcpv6_pernet_subsys; 2248 2249 out: 2250 return ret; 2251 2252 out_tcpv6_pernet_subsys: 2253 unregister_pernet_subsys(&tcpv6_net_ops); 2254 out_tcpv6_protosw: 2255 inet6_unregister_protosw(&tcpv6_protosw); 2256 out_tcpv6_protocol: 2257 inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP); 2258 goto out; 2259 } 2260 2261 void tcpv6_exit(void) 2262 { 2263 unregister_pernet_subsys(&tcpv6_net_ops); 2264 inet6_unregister_protosw(&tcpv6_protosw); 2265 inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP); 2266 } 2267