1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * Implementation of the Transmission Control Protocol(TCP). 8 * 9 * IPv4 specific functions 10 * 11 * code split from: 12 * linux/ipv4/tcp.c 13 * linux/ipv4/tcp_input.c 14 * linux/ipv4/tcp_output.c 15 * 16 * See tcp.c for author information 17 */ 18 19 /* 20 * Changes: 21 * David S. Miller : New socket lookup architecture. 22 * This code is dedicated to John Dyson. 23 * David S. Miller : Change semantics of established hash, 24 * half is devoted to TIME_WAIT sockets 25 * and the rest go in the other half. 26 * Andi Kleen : Add support for syncookies and fixed 27 * some bugs: ip options weren't passed to 28 * the TCP layer, missed a check for an 29 * ACK bit. 30 * Andi Kleen : Implemented fast path mtu discovery. 31 * Fixed many serious bugs in the 32 * request_sock handling and moved 33 * most of it into the af independent code. 34 * Added tail drop and some other bugfixes. 35 * Added new listen semantics. 36 * Mike McLagan : Routing by source 37 * Juan Jose Ciarlante: ip_dynaddr bits 38 * Andi Kleen: various fixes. 39 * Vitaly E. Lavrov : Transparent proxy revived after year 40 * coma. 41 * Andi Kleen : Fix new listen. 42 * Andi Kleen : Fix accept error reporting. 43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which 44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind 45 * a single port at the same time. 46 */ 47 48 #define pr_fmt(fmt) "TCP: " fmt 49 50 #include <linux/bottom_half.h> 51 #include <linux/types.h> 52 #include <linux/fcntl.h> 53 #include <linux/module.h> 54 #include <linux/random.h> 55 #include <linux/cache.h> 56 #include <linux/jhash.h> 57 #include <linux/init.h> 58 #include <linux/times.h> 59 #include <linux/slab.h> 60 #include <linux/sched.h> 61 62 #include <net/net_namespace.h> 63 #include <net/icmp.h> 64 #include <net/inet_hashtables.h> 65 #include <net/tcp.h> 66 #include <net/transp_v6.h> 67 #include <net/ipv6.h> 68 #include <net/inet_common.h> 69 #include <net/timewait_sock.h> 70 #include <net/xfrm.h> 71 #include <net/secure_seq.h> 72 #include <net/busy_poll.h> 73 #include <net/rstreason.h> 74 75 #include <linux/inet.h> 76 #include <linux/ipv6.h> 77 #include <linux/stddef.h> 78 #include <linux/proc_fs.h> 79 #include <linux/seq_file.h> 80 #include <linux/inetdevice.h> 81 #include <linux/btf_ids.h> 82 83 #include <crypto/hash.h> 84 #include <linux/scatterlist.h> 85 86 #include <trace/events/tcp.h> 87 88 #ifdef CONFIG_TCP_MD5SIG 89 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 90 __be32 daddr, __be32 saddr, const struct tcphdr *th); 91 #endif 92 93 struct inet_hashinfo tcp_hashinfo; 94 EXPORT_SYMBOL(tcp_hashinfo); 95 96 static DEFINE_PER_CPU(struct sock_bh_locked, ipv4_tcp_sk) = { 97 .bh_lock = INIT_LOCAL_LOCK(bh_lock), 98 }; 99 100 static DEFINE_MUTEX(tcp_exit_batch_mutex); 101 102 static u32 tcp_v4_init_seq(const struct sk_buff *skb) 103 { 104 return secure_tcp_seq(ip_hdr(skb)->daddr, 105 ip_hdr(skb)->saddr, 106 tcp_hdr(skb)->dest, 107 tcp_hdr(skb)->source); 108 } 109 110 static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb) 111 { 112 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr); 113 } 114 115 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) 116 { 117 int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse); 118 const struct inet_timewait_sock *tw = inet_twsk(sktw); 119 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw); 120 struct tcp_sock *tp = tcp_sk(sk); 121 int ts_recent_stamp; 122 123 if (reuse == 2) { 124 /* Still does not detect *everything* that goes through 125 * lo, since we require a loopback src or dst address 126 * or direct binding to 'lo' interface. 127 */ 128 bool loopback = false; 129 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX) 130 loopback = true; 131 #if IS_ENABLED(CONFIG_IPV6) 132 if (tw->tw_family == AF_INET6) { 133 if (ipv6_addr_loopback(&tw->tw_v6_daddr) || 134 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) || 135 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) || 136 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr)) 137 loopback = true; 138 } else 139 #endif 140 { 141 if (ipv4_is_loopback(tw->tw_daddr) || 142 ipv4_is_loopback(tw->tw_rcv_saddr)) 143 loopback = true; 144 } 145 if (!loopback) 146 reuse = 0; 147 } 148 149 /* With PAWS, it is safe from the viewpoint 150 of data integrity. Even without PAWS it is safe provided sequence 151 spaces do not overlap i.e. at data rates <= 80Mbit/sec. 152 153 Actually, the idea is close to VJ's one, only timestamp cache is 154 held not per host, but per port pair and TW bucket is used as state 155 holder. 156 157 If TW bucket has been already destroyed we fall back to VJ's scheme 158 and use initial timestamp retrieved from peer table. 159 */ 160 ts_recent_stamp = READ_ONCE(tcptw->tw_ts_recent_stamp); 161 if (ts_recent_stamp && 162 (!twp || (reuse && time_after32(ktime_get_seconds(), 163 ts_recent_stamp)))) { 164 /* inet_twsk_hashdance_schedule() sets sk_refcnt after putting twsk 165 * and releasing the bucket lock. 166 */ 167 if (unlikely(!refcount_inc_not_zero(&sktw->sk_refcnt))) 168 return 0; 169 170 /* In case of repair and re-using TIME-WAIT sockets we still 171 * want to be sure that it is safe as above but honor the 172 * sequence numbers and time stamps set as part of the repair 173 * process. 174 * 175 * Without this check re-using a TIME-WAIT socket with TCP 176 * repair would accumulate a -1 on the repair assigned 177 * sequence number. The first time it is reused the sequence 178 * is -1, the second time -2, etc. This fixes that issue 179 * without appearing to create any others. 180 */ 181 if (likely(!tp->repair)) { 182 u32 seq = tcptw->tw_snd_nxt + 65535 + 2; 183 184 if (!seq) 185 seq = 1; 186 WRITE_ONCE(tp->write_seq, seq); 187 tp->rx_opt.ts_recent = READ_ONCE(tcptw->tw_ts_recent); 188 tp->rx_opt.ts_recent_stamp = ts_recent_stamp; 189 } 190 191 return 1; 192 } 193 194 return 0; 195 } 196 EXPORT_SYMBOL_GPL(tcp_twsk_unique); 197 198 static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr, 199 int addr_len) 200 { 201 /* This check is replicated from tcp_v4_connect() and intended to 202 * prevent BPF program called below from accessing bytes that are out 203 * of the bound specified by user in addr_len. 204 */ 205 if (addr_len < sizeof(struct sockaddr_in)) 206 return -EINVAL; 207 208 sock_owned_by_me(sk); 209 210 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr, &addr_len); 211 } 212 213 /* This will initiate an outgoing connection. */ 214 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 215 { 216 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; 217 struct inet_timewait_death_row *tcp_death_row; 218 struct inet_sock *inet = inet_sk(sk); 219 struct tcp_sock *tp = tcp_sk(sk); 220 struct ip_options_rcu *inet_opt; 221 struct net *net = sock_net(sk); 222 __be16 orig_sport, orig_dport; 223 __be32 daddr, nexthop; 224 struct flowi4 *fl4; 225 struct rtable *rt; 226 int err; 227 228 if (addr_len < sizeof(struct sockaddr_in)) 229 return -EINVAL; 230 231 if (usin->sin_family != AF_INET) 232 return -EAFNOSUPPORT; 233 234 nexthop = daddr = usin->sin_addr.s_addr; 235 inet_opt = rcu_dereference_protected(inet->inet_opt, 236 lockdep_sock_is_held(sk)); 237 if (inet_opt && inet_opt->opt.srr) { 238 if (!daddr) 239 return -EINVAL; 240 nexthop = inet_opt->opt.faddr; 241 } 242 243 orig_sport = inet->inet_sport; 244 orig_dport = usin->sin_port; 245 fl4 = &inet->cork.fl.u.ip4; 246 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr, 247 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport, 248 orig_dport, sk); 249 if (IS_ERR(rt)) { 250 err = PTR_ERR(rt); 251 if (err == -ENETUNREACH) 252 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); 253 return err; 254 } 255 256 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { 257 ip_rt_put(rt); 258 return -ENETUNREACH; 259 } 260 261 if (!inet_opt || !inet_opt->opt.srr) 262 daddr = fl4->daddr; 263 264 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row; 265 266 if (!inet->inet_saddr) { 267 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET); 268 if (err) { 269 ip_rt_put(rt); 270 return err; 271 } 272 } else { 273 sk_rcv_saddr_set(sk, inet->inet_saddr); 274 } 275 276 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) { 277 /* Reset inherited state */ 278 tp->rx_opt.ts_recent = 0; 279 tp->rx_opt.ts_recent_stamp = 0; 280 if (likely(!tp->repair)) 281 WRITE_ONCE(tp->write_seq, 0); 282 } 283 284 inet->inet_dport = usin->sin_port; 285 sk_daddr_set(sk, daddr); 286 287 inet_csk(sk)->icsk_ext_hdr_len = 0; 288 if (inet_opt) 289 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen; 290 291 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT; 292 293 /* Socket identity is still unknown (sport may be zero). 294 * However we set state to SYN-SENT and not releasing socket 295 * lock select source port, enter ourselves into the hash tables and 296 * complete initialization after this. 297 */ 298 tcp_set_state(sk, TCP_SYN_SENT); 299 err = inet_hash_connect(tcp_death_row, sk); 300 if (err) 301 goto failure; 302 303 sk_set_txhash(sk); 304 305 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport, 306 inet->inet_sport, inet->inet_dport, sk); 307 if (IS_ERR(rt)) { 308 err = PTR_ERR(rt); 309 rt = NULL; 310 goto failure; 311 } 312 tp->tcp_usec_ts = dst_tcp_usec_ts(&rt->dst); 313 /* OK, now commit destination to socket. */ 314 sk->sk_gso_type = SKB_GSO_TCPV4; 315 sk_setup_caps(sk, &rt->dst); 316 rt = NULL; 317 318 if (likely(!tp->repair)) { 319 if (!tp->write_seq) 320 WRITE_ONCE(tp->write_seq, 321 secure_tcp_seq(inet->inet_saddr, 322 inet->inet_daddr, 323 inet->inet_sport, 324 usin->sin_port)); 325 WRITE_ONCE(tp->tsoffset, 326 secure_tcp_ts_off(net, inet->inet_saddr, 327 inet->inet_daddr)); 328 } 329 330 atomic_set(&inet->inet_id, get_random_u16()); 331 332 if (tcp_fastopen_defer_connect(sk, &err)) 333 return err; 334 if (err) 335 goto failure; 336 337 err = tcp_connect(sk); 338 339 if (err) 340 goto failure; 341 342 return 0; 343 344 failure: 345 /* 346 * This unhashes the socket and releases the local port, 347 * if necessary. 348 */ 349 tcp_set_state(sk, TCP_CLOSE); 350 inet_bhash2_reset_saddr(sk); 351 ip_rt_put(rt); 352 sk->sk_route_caps = 0; 353 inet->inet_dport = 0; 354 return err; 355 } 356 EXPORT_SYMBOL(tcp_v4_connect); 357 358 /* 359 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191. 360 * It can be called through tcp_release_cb() if socket was owned by user 361 * at the time tcp_v4_err() was called to handle ICMP message. 362 */ 363 void tcp_v4_mtu_reduced(struct sock *sk) 364 { 365 struct inet_sock *inet = inet_sk(sk); 366 struct dst_entry *dst; 367 u32 mtu; 368 369 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) 370 return; 371 mtu = READ_ONCE(tcp_sk(sk)->mtu_info); 372 dst = inet_csk_update_pmtu(sk, mtu); 373 if (!dst) 374 return; 375 376 /* Something is about to be wrong... Remember soft error 377 * for the case, if this connection will not able to recover. 378 */ 379 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) 380 WRITE_ONCE(sk->sk_err_soft, EMSGSIZE); 381 382 mtu = dst_mtu(dst); 383 384 if (inet->pmtudisc != IP_PMTUDISC_DONT && 385 ip_sk_accept_pmtu(sk) && 386 inet_csk(sk)->icsk_pmtu_cookie > mtu) { 387 tcp_sync_mss(sk, mtu); 388 389 /* Resend the TCP packet because it's 390 * clear that the old packet has been 391 * dropped. This is the new "fast" path mtu 392 * discovery. 393 */ 394 tcp_simple_retransmit(sk); 395 } /* else let the usual retransmit timer handle it */ 396 } 397 EXPORT_SYMBOL(tcp_v4_mtu_reduced); 398 399 static void do_redirect(struct sk_buff *skb, struct sock *sk) 400 { 401 struct dst_entry *dst = __sk_dst_check(sk, 0); 402 403 if (dst) 404 dst->ops->redirect(dst, sk, skb); 405 } 406 407 408 /* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */ 409 void tcp_req_err(struct sock *sk, u32 seq, bool abort) 410 { 411 struct request_sock *req = inet_reqsk(sk); 412 struct net *net = sock_net(sk); 413 414 /* ICMPs are not backlogged, hence we cannot get 415 * an established socket here. 416 */ 417 if (seq != tcp_rsk(req)->snt_isn) { 418 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 419 } else if (abort) { 420 /* 421 * Still in SYN_RECV, just remove it silently. 422 * There is no good way to pass the error to the newly 423 * created socket, and POSIX does not want network 424 * errors returned from accept(). 425 */ 426 inet_csk_reqsk_queue_drop(req->rsk_listener, req); 427 tcp_listendrop(req->rsk_listener); 428 } 429 reqsk_put(req); 430 } 431 EXPORT_SYMBOL(tcp_req_err); 432 433 /* TCP-LD (RFC 6069) logic */ 434 void tcp_ld_RTO_revert(struct sock *sk, u32 seq) 435 { 436 struct inet_connection_sock *icsk = inet_csk(sk); 437 struct tcp_sock *tp = tcp_sk(sk); 438 struct sk_buff *skb; 439 s32 remaining; 440 u32 delta_us; 441 442 if (sock_owned_by_user(sk)) 443 return; 444 445 if (seq != tp->snd_una || !icsk->icsk_retransmits || 446 !icsk->icsk_backoff) 447 return; 448 449 skb = tcp_rtx_queue_head(sk); 450 if (WARN_ON_ONCE(!skb)) 451 return; 452 453 icsk->icsk_backoff--; 454 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT; 455 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX); 456 457 tcp_mstamp_refresh(tp); 458 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb)); 459 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us); 460 461 if (remaining > 0) { 462 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 463 remaining, TCP_RTO_MAX); 464 } else { 465 /* RTO revert clocked out retransmission. 466 * Will retransmit now. 467 */ 468 tcp_retransmit_timer(sk); 469 } 470 } 471 EXPORT_SYMBOL(tcp_ld_RTO_revert); 472 473 /* 474 * This routine is called by the ICMP module when it gets some 475 * sort of error condition. If err < 0 then the socket should 476 * be closed and the error returned to the user. If err > 0 477 * it's just the icmp type << 8 | icmp code. After adjustment 478 * header points to the first 8 bytes of the tcp header. We need 479 * to find the appropriate port. 480 * 481 * The locking strategy used here is very "optimistic". When 482 * someone else accesses the socket the ICMP is just dropped 483 * and for some paths there is no check at all. 484 * A more general error queue to queue errors for later handling 485 * is probably better. 486 * 487 */ 488 489 int tcp_v4_err(struct sk_buff *skb, u32 info) 490 { 491 const struct iphdr *iph = (const struct iphdr *)skb->data; 492 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2)); 493 struct tcp_sock *tp; 494 const int type = icmp_hdr(skb)->type; 495 const int code = icmp_hdr(skb)->code; 496 struct sock *sk; 497 struct request_sock *fastopen; 498 u32 seq, snd_una; 499 int err; 500 struct net *net = dev_net(skb->dev); 501 502 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, 503 iph->daddr, th->dest, iph->saddr, 504 ntohs(th->source), inet_iif(skb), 0); 505 if (!sk) { 506 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS); 507 return -ENOENT; 508 } 509 if (sk->sk_state == TCP_TIME_WAIT) { 510 /* To increase the counter of ignored icmps for TCP-AO */ 511 tcp_ao_ignore_icmp(sk, AF_INET, type, code); 512 inet_twsk_put(inet_twsk(sk)); 513 return 0; 514 } 515 seq = ntohl(th->seq); 516 if (sk->sk_state == TCP_NEW_SYN_RECV) { 517 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB || 518 type == ICMP_TIME_EXCEEDED || 519 (type == ICMP_DEST_UNREACH && 520 (code == ICMP_NET_UNREACH || 521 code == ICMP_HOST_UNREACH))); 522 return 0; 523 } 524 525 if (tcp_ao_ignore_icmp(sk, AF_INET, type, code)) { 526 sock_put(sk); 527 return 0; 528 } 529 530 bh_lock_sock(sk); 531 /* If too many ICMPs get dropped on busy 532 * servers this needs to be solved differently. 533 * We do take care of PMTU discovery (RFC1191) special case : 534 * we can receive locally generated ICMP messages while socket is held. 535 */ 536 if (sock_owned_by_user(sk)) { 537 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)) 538 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); 539 } 540 if (sk->sk_state == TCP_CLOSE) 541 goto out; 542 543 if (static_branch_unlikely(&ip4_min_ttl)) { 544 /* min_ttl can be changed concurrently from do_ip_setsockopt() */ 545 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) { 546 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); 547 goto out; 548 } 549 } 550 551 tp = tcp_sk(sk); 552 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */ 553 fastopen = rcu_dereference(tp->fastopen_rsk); 554 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una; 555 if (sk->sk_state != TCP_LISTEN && 556 !between(seq, snd_una, tp->snd_nxt)) { 557 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 558 goto out; 559 } 560 561 switch (type) { 562 case ICMP_REDIRECT: 563 if (!sock_owned_by_user(sk)) 564 do_redirect(skb, sk); 565 goto out; 566 case ICMP_SOURCE_QUENCH: 567 /* Just silently ignore these. */ 568 goto out; 569 case ICMP_PARAMETERPROB: 570 err = EPROTO; 571 break; 572 case ICMP_DEST_UNREACH: 573 if (code > NR_ICMP_UNREACH) 574 goto out; 575 576 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ 577 /* We are not interested in TCP_LISTEN and open_requests 578 * (SYN-ACKs send out by Linux are always <576bytes so 579 * they should go through unfragmented). 580 */ 581 if (sk->sk_state == TCP_LISTEN) 582 goto out; 583 584 WRITE_ONCE(tp->mtu_info, info); 585 if (!sock_owned_by_user(sk)) { 586 tcp_v4_mtu_reduced(sk); 587 } else { 588 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags)) 589 sock_hold(sk); 590 } 591 goto out; 592 } 593 594 err = icmp_err_convert[code].errno; 595 /* check if this ICMP message allows revert of backoff. 596 * (see RFC 6069) 597 */ 598 if (!fastopen && 599 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH)) 600 tcp_ld_RTO_revert(sk, seq); 601 break; 602 case ICMP_TIME_EXCEEDED: 603 err = EHOSTUNREACH; 604 break; 605 default: 606 goto out; 607 } 608 609 switch (sk->sk_state) { 610 case TCP_SYN_SENT: 611 case TCP_SYN_RECV: 612 /* Only in fast or simultaneous open. If a fast open socket is 613 * already accepted it is treated as a connected one below. 614 */ 615 if (fastopen && !fastopen->sk) 616 break; 617 618 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th); 619 620 if (!sock_owned_by_user(sk)) 621 tcp_done_with_error(sk, err); 622 else 623 WRITE_ONCE(sk->sk_err_soft, err); 624 goto out; 625 } 626 627 /* If we've already connected we will keep trying 628 * until we time out, or the user gives up. 629 * 630 * rfc1122 4.2.3.9 allows to consider as hard errors 631 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, 632 * but it is obsoleted by pmtu discovery). 633 * 634 * Note, that in modern internet, where routing is unreliable 635 * and in each dark corner broken firewalls sit, sending random 636 * errors ordered by their masters even this two messages finally lose 637 * their original sense (even Linux sends invalid PORT_UNREACHs) 638 * 639 * Now we are in compliance with RFCs. 640 * --ANK (980905) 641 */ 642 643 if (!sock_owned_by_user(sk) && 644 inet_test_bit(RECVERR, sk)) { 645 WRITE_ONCE(sk->sk_err, err); 646 sk_error_report(sk); 647 } else { /* Only an error on timeout */ 648 WRITE_ONCE(sk->sk_err_soft, err); 649 } 650 651 out: 652 bh_unlock_sock(sk); 653 sock_put(sk); 654 return 0; 655 } 656 657 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr) 658 { 659 struct tcphdr *th = tcp_hdr(skb); 660 661 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0); 662 skb->csum_start = skb_transport_header(skb) - skb->head; 663 skb->csum_offset = offsetof(struct tcphdr, check); 664 } 665 666 /* This routine computes an IPv4 TCP checksum. */ 667 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) 668 { 669 const struct inet_sock *inet = inet_sk(sk); 670 671 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr); 672 } 673 EXPORT_SYMBOL(tcp_v4_send_check); 674 675 #define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32)) 676 677 static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb, 678 const struct tcp_ao_hdr *aoh, 679 struct ip_reply_arg *arg, struct tcphdr *reply, 680 __be32 reply_options[REPLY_OPTIONS_LEN]) 681 { 682 #ifdef CONFIG_TCP_AO 683 int sdif = tcp_v4_sdif(skb); 684 int dif = inet_iif(skb); 685 int l3index = sdif ? dif : 0; 686 bool allocated_traffic_key; 687 struct tcp_ao_key *key; 688 char *traffic_key; 689 bool drop = true; 690 u32 ao_sne = 0; 691 u8 keyid; 692 693 rcu_read_lock(); 694 if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, ntohl(reply->seq), 695 &key, &traffic_key, &allocated_traffic_key, 696 &keyid, &ao_sne)) 697 goto out; 698 699 reply_options[0] = htonl((TCPOPT_AO << 24) | (tcp_ao_len(key) << 16) | 700 (aoh->rnext_keyid << 8) | keyid); 701 arg->iov[0].iov_len += tcp_ao_len_aligned(key); 702 reply->doff = arg->iov[0].iov_len / 4; 703 704 if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1], 705 key, traffic_key, 706 (union tcp_ao_addr *)&ip_hdr(skb)->saddr, 707 (union tcp_ao_addr *)&ip_hdr(skb)->daddr, 708 reply, ao_sne)) 709 goto out; 710 drop = false; 711 out: 712 rcu_read_unlock(); 713 if (allocated_traffic_key) 714 kfree(traffic_key); 715 return drop; 716 #else 717 return true; 718 #endif 719 } 720 721 /* 722 * This routine will send an RST to the other tcp. 723 * 724 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.) 725 * for reset. 726 * Answer: if a packet caused RST, it is not for a socket 727 * existing in our system, if it is matched to a socket, 728 * it is just duplicate segment or bug in other side's TCP. 729 * So that we build reply only basing on parameters 730 * arrived with segment. 731 * Exception: precedence violation. We do not implement it in any case. 732 */ 733 734 static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb, 735 enum sk_rst_reason reason) 736 { 737 const struct tcphdr *th = tcp_hdr(skb); 738 struct { 739 struct tcphdr th; 740 __be32 opt[REPLY_OPTIONS_LEN]; 741 } rep; 742 const __u8 *md5_hash_location = NULL; 743 const struct tcp_ao_hdr *aoh; 744 struct ip_reply_arg arg; 745 #ifdef CONFIG_TCP_MD5SIG 746 struct tcp_md5sig_key *key = NULL; 747 unsigned char newhash[16]; 748 struct sock *sk1 = NULL; 749 int genhash; 750 #endif 751 u64 transmit_time = 0; 752 struct sock *ctl_sk; 753 struct net *net; 754 u32 txhash = 0; 755 756 /* Never send a reset in response to a reset. */ 757 if (th->rst) 758 return; 759 760 /* If sk not NULL, it means we did a successful lookup and incoming 761 * route had to be correct. prequeue might have dropped our dst. 762 */ 763 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL) 764 return; 765 766 /* Swap the send and the receive. */ 767 memset(&rep, 0, sizeof(rep)); 768 rep.th.dest = th->source; 769 rep.th.source = th->dest; 770 rep.th.doff = sizeof(struct tcphdr) / 4; 771 rep.th.rst = 1; 772 773 if (th->ack) { 774 rep.th.seq = th->ack_seq; 775 } else { 776 rep.th.ack = 1; 777 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin + 778 skb->len - (th->doff << 2)); 779 } 780 781 memset(&arg, 0, sizeof(arg)); 782 arg.iov[0].iov_base = (unsigned char *)&rep; 783 arg.iov[0].iov_len = sizeof(rep.th); 784 785 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); 786 787 /* Invalid TCP option size or twice included auth */ 788 if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh)) 789 return; 790 791 if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt)) 792 return; 793 794 #ifdef CONFIG_TCP_MD5SIG 795 rcu_read_lock(); 796 if (sk && sk_fullsock(sk)) { 797 const union tcp_md5_addr *addr; 798 int l3index; 799 800 /* sdif set, means packet ingressed via a device 801 * in an L3 domain and inet_iif is set to it. 802 */ 803 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; 804 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 805 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 806 } else if (md5_hash_location) { 807 const union tcp_md5_addr *addr; 808 int sdif = tcp_v4_sdif(skb); 809 int dif = inet_iif(skb); 810 int l3index; 811 812 /* 813 * active side is lost. Try to find listening socket through 814 * source port, and then find md5 key through listening socket. 815 * we are not loose security here: 816 * Incoming packet is checked with md5 hash with finding key, 817 * no RST generated if md5 hash doesn't match. 818 */ 819 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo, 820 NULL, 0, ip_hdr(skb)->saddr, 821 th->source, ip_hdr(skb)->daddr, 822 ntohs(th->source), dif, sdif); 823 /* don't send rst if it can't find key */ 824 if (!sk1) 825 goto out; 826 827 /* sdif set, means packet ingressed via a device 828 * in an L3 domain and dif is set to it. 829 */ 830 l3index = sdif ? dif : 0; 831 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 832 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET); 833 if (!key) 834 goto out; 835 836 837 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb); 838 if (genhash || memcmp(md5_hash_location, newhash, 16) != 0) 839 goto out; 840 841 } 842 843 if (key) { 844 rep.opt[0] = htonl((TCPOPT_NOP << 24) | 845 (TCPOPT_NOP << 16) | 846 (TCPOPT_MD5SIG << 8) | 847 TCPOLEN_MD5SIG); 848 /* Update length and the length the header thinks exists */ 849 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 850 rep.th.doff = arg.iov[0].iov_len / 4; 851 852 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1], 853 key, ip_hdr(skb)->saddr, 854 ip_hdr(skb)->daddr, &rep.th); 855 } 856 #endif 857 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */ 858 if (rep.opt[0] == 0) { 859 __be32 mrst = mptcp_reset_option(skb); 860 861 if (mrst) { 862 rep.opt[0] = mrst; 863 arg.iov[0].iov_len += sizeof(mrst); 864 rep.th.doff = arg.iov[0].iov_len / 4; 865 } 866 } 867 868 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 869 ip_hdr(skb)->saddr, /* XXX */ 870 arg.iov[0].iov_len, IPPROTO_TCP, 0); 871 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 872 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0; 873 874 /* When socket is gone, all binding information is lost. 875 * routing might fail in this case. No choice here, if we choose to force 876 * input interface, we will misroute in case of asymmetric route. 877 */ 878 if (sk) 879 arg.bound_dev_if = sk->sk_bound_dev_if; 880 881 trace_tcp_send_reset(sk, skb, reason); 882 883 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) != 884 offsetof(struct inet_timewait_sock, tw_bound_dev_if)); 885 886 arg.tos = ip_hdr(skb)->tos; 887 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL); 888 local_bh_disable(); 889 local_lock_nested_bh(&ipv4_tcp_sk.bh_lock); 890 ctl_sk = this_cpu_read(ipv4_tcp_sk.sock); 891 892 sock_net_set(ctl_sk, net); 893 if (sk) { 894 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ? 895 inet_twsk(sk)->tw_mark : sk->sk_mark; 896 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ? 897 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority); 898 transmit_time = tcp_transmit_time(sk); 899 xfrm_sk_clone_policy(ctl_sk, sk); 900 txhash = (sk->sk_state == TCP_TIME_WAIT) ? 901 inet_twsk(sk)->tw_txhash : sk->sk_txhash; 902 } else { 903 ctl_sk->sk_mark = 0; 904 ctl_sk->sk_priority = 0; 905 } 906 ip_send_unicast_reply(ctl_sk, 907 skb, &TCP_SKB_CB(skb)->header.h4.opt, 908 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 909 &arg, arg.iov[0].iov_len, 910 transmit_time, txhash); 911 912 xfrm_sk_free_policy(ctl_sk); 913 sock_net_set(ctl_sk, &init_net); 914 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); 915 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS); 916 local_unlock_nested_bh(&ipv4_tcp_sk.bh_lock); 917 local_bh_enable(); 918 919 #ifdef CONFIG_TCP_MD5SIG 920 out: 921 rcu_read_unlock(); 922 #endif 923 } 924 925 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states 926 outside socket context is ugly, certainly. What can I do? 927 */ 928 929 static void tcp_v4_send_ack(const struct sock *sk, 930 struct sk_buff *skb, u32 seq, u32 ack, 931 u32 win, u32 tsval, u32 tsecr, int oif, 932 struct tcp_key *key, 933 int reply_flags, u8 tos, u32 txhash) 934 { 935 const struct tcphdr *th = tcp_hdr(skb); 936 struct { 937 struct tcphdr th; 938 __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)]; 939 } rep; 940 struct net *net = sock_net(sk); 941 struct ip_reply_arg arg; 942 struct sock *ctl_sk; 943 u64 transmit_time; 944 945 memset(&rep.th, 0, sizeof(struct tcphdr)); 946 memset(&arg, 0, sizeof(arg)); 947 948 arg.iov[0].iov_base = (unsigned char *)&rep; 949 arg.iov[0].iov_len = sizeof(rep.th); 950 if (tsecr) { 951 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 952 (TCPOPT_TIMESTAMP << 8) | 953 TCPOLEN_TIMESTAMP); 954 rep.opt[1] = htonl(tsval); 955 rep.opt[2] = htonl(tsecr); 956 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED; 957 } 958 959 /* Swap the send and the receive. */ 960 rep.th.dest = th->source; 961 rep.th.source = th->dest; 962 rep.th.doff = arg.iov[0].iov_len / 4; 963 rep.th.seq = htonl(seq); 964 rep.th.ack_seq = htonl(ack); 965 rep.th.ack = 1; 966 rep.th.window = htons(win); 967 968 #ifdef CONFIG_TCP_MD5SIG 969 if (tcp_key_is_md5(key)) { 970 int offset = (tsecr) ? 3 : 0; 971 972 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) | 973 (TCPOPT_NOP << 16) | 974 (TCPOPT_MD5SIG << 8) | 975 TCPOLEN_MD5SIG); 976 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 977 rep.th.doff = arg.iov[0].iov_len/4; 978 979 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset], 980 key->md5_key, ip_hdr(skb)->saddr, 981 ip_hdr(skb)->daddr, &rep.th); 982 } 983 #endif 984 #ifdef CONFIG_TCP_AO 985 if (tcp_key_is_ao(key)) { 986 int offset = (tsecr) ? 3 : 0; 987 988 rep.opt[offset++] = htonl((TCPOPT_AO << 24) | 989 (tcp_ao_len(key->ao_key) << 16) | 990 (key->ao_key->sndid << 8) | 991 key->rcv_next); 992 arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key); 993 rep.th.doff = arg.iov[0].iov_len / 4; 994 995 tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset], 996 key->ao_key, key->traffic_key, 997 (union tcp_ao_addr *)&ip_hdr(skb)->saddr, 998 (union tcp_ao_addr *)&ip_hdr(skb)->daddr, 999 &rep.th, key->sne); 1000 } 1001 #endif 1002 arg.flags = reply_flags; 1003 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 1004 ip_hdr(skb)->saddr, /* XXX */ 1005 arg.iov[0].iov_len, IPPROTO_TCP, 0); 1006 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 1007 if (oif) 1008 arg.bound_dev_if = oif; 1009 arg.tos = tos; 1010 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL); 1011 local_bh_disable(); 1012 local_lock_nested_bh(&ipv4_tcp_sk.bh_lock); 1013 ctl_sk = this_cpu_read(ipv4_tcp_sk.sock); 1014 sock_net_set(ctl_sk, net); 1015 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ? 1016 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark); 1017 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ? 1018 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority); 1019 transmit_time = tcp_transmit_time(sk); 1020 ip_send_unicast_reply(ctl_sk, 1021 skb, &TCP_SKB_CB(skb)->header.h4.opt, 1022 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 1023 &arg, arg.iov[0].iov_len, 1024 transmit_time, txhash); 1025 1026 sock_net_set(ctl_sk, &init_net); 1027 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); 1028 local_unlock_nested_bh(&ipv4_tcp_sk.bh_lock); 1029 local_bh_enable(); 1030 } 1031 1032 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) 1033 { 1034 struct inet_timewait_sock *tw = inet_twsk(sk); 1035 struct tcp_timewait_sock *tcptw = tcp_twsk(sk); 1036 struct tcp_key key = {}; 1037 #ifdef CONFIG_TCP_AO 1038 struct tcp_ao_info *ao_info; 1039 1040 if (static_branch_unlikely(&tcp_ao_needed.key)) { 1041 /* FIXME: the segment to-be-acked is not verified yet */ 1042 ao_info = rcu_dereference(tcptw->ao_info); 1043 if (ao_info) { 1044 const struct tcp_ao_hdr *aoh; 1045 1046 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) { 1047 inet_twsk_put(tw); 1048 return; 1049 } 1050 1051 if (aoh) 1052 key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1); 1053 } 1054 } 1055 if (key.ao_key) { 1056 struct tcp_ao_key *rnext_key; 1057 1058 key.traffic_key = snd_other_key(key.ao_key); 1059 key.sne = READ_ONCE(ao_info->snd_sne); 1060 rnext_key = READ_ONCE(ao_info->rnext_key); 1061 key.rcv_next = rnext_key->rcvid; 1062 key.type = TCP_KEY_AO; 1063 #else 1064 if (0) { 1065 #endif 1066 } else if (static_branch_tcp_md5()) { 1067 key.md5_key = tcp_twsk_md5_key(tcptw); 1068 if (key.md5_key) 1069 key.type = TCP_KEY_MD5; 1070 } 1071 1072 tcp_v4_send_ack(sk, skb, 1073 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, 1074 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, 1075 tcp_tw_tsval(tcptw), 1076 READ_ONCE(tcptw->tw_ts_recent), 1077 tw->tw_bound_dev_if, &key, 1078 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0, 1079 tw->tw_tos, 1080 tw->tw_txhash); 1081 1082 inet_twsk_put(tw); 1083 } 1084 1085 static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, 1086 struct request_sock *req) 1087 { 1088 struct tcp_key key = {}; 1089 1090 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV 1091 * sk->sk_state == TCP_SYN_RECV -> for Fast Open. 1092 */ 1093 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 : 1094 tcp_sk(sk)->snd_nxt; 1095 1096 #ifdef CONFIG_TCP_AO 1097 if (static_branch_unlikely(&tcp_ao_needed.key) && 1098 tcp_rsk_used_ao(req)) { 1099 const union tcp_md5_addr *addr; 1100 const struct tcp_ao_hdr *aoh; 1101 int l3index; 1102 1103 /* Invalid TCP option size or twice included auth */ 1104 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) 1105 return; 1106 if (!aoh) 1107 return; 1108 1109 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 1110 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; 1111 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, 1112 aoh->rnext_keyid, -1); 1113 if (unlikely(!key.ao_key)) { 1114 /* Send ACK with any matching MKT for the peer */ 1115 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1); 1116 /* Matching key disappeared (user removed the key?) 1117 * let the handshake timeout. 1118 */ 1119 if (!key.ao_key) { 1120 net_info_ratelimited("TCP-AO key for (%pI4, %d)->(%pI4, %d) suddenly disappeared, won't ACK new connection\n", 1121 addr, 1122 ntohs(tcp_hdr(skb)->source), 1123 &ip_hdr(skb)->daddr, 1124 ntohs(tcp_hdr(skb)->dest)); 1125 return; 1126 } 1127 } 1128 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC); 1129 if (!key.traffic_key) 1130 return; 1131 1132 key.type = TCP_KEY_AO; 1133 key.rcv_next = aoh->keyid; 1134 tcp_v4_ao_calc_key_rsk(key.ao_key, key.traffic_key, req); 1135 #else 1136 if (0) { 1137 #endif 1138 } else if (static_branch_tcp_md5()) { 1139 const union tcp_md5_addr *addr; 1140 int l3index; 1141 1142 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 1143 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; 1144 key.md5_key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 1145 if (key.md5_key) 1146 key.type = TCP_KEY_MD5; 1147 } 1148 1149 tcp_v4_send_ack(sk, skb, seq, 1150 tcp_rsk(req)->rcv_nxt, 1151 tcp_synack_window(req) >> inet_rsk(req)->rcv_wscale, 1152 tcp_rsk_tsval(tcp_rsk(req)), 1153 READ_ONCE(req->ts_recent), 1154 0, &key, 1155 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, 1156 ip_hdr(skb)->tos, 1157 READ_ONCE(tcp_rsk(req)->txhash)); 1158 if (tcp_key_is_ao(&key)) 1159 kfree(key.traffic_key); 1160 } 1161 1162 /* 1163 * Send a SYN-ACK after having received a SYN. 1164 * This still operates on a request_sock only, not on a big 1165 * socket. 1166 */ 1167 static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, 1168 struct flowi *fl, 1169 struct request_sock *req, 1170 struct tcp_fastopen_cookie *foc, 1171 enum tcp_synack_type synack_type, 1172 struct sk_buff *syn_skb) 1173 { 1174 const struct inet_request_sock *ireq = inet_rsk(req); 1175 struct flowi4 fl4; 1176 int err = -1; 1177 struct sk_buff *skb; 1178 u8 tos; 1179 1180 /* First, grab a route. */ 1181 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL) 1182 return -1; 1183 1184 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb); 1185 1186 if (skb) { 1187 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); 1188 1189 tos = READ_ONCE(inet_sk(sk)->tos); 1190 1191 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)) 1192 tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) | 1193 (tos & INET_ECN_MASK); 1194 1195 if (!INET_ECN_is_capable(tos) && 1196 tcp_bpf_ca_needs_ecn((struct sock *)req)) 1197 tos |= INET_ECN_ECT_0; 1198 1199 rcu_read_lock(); 1200 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, 1201 ireq->ir_rmt_addr, 1202 rcu_dereference(ireq->ireq_opt), 1203 tos); 1204 rcu_read_unlock(); 1205 err = net_xmit_eval(err); 1206 } 1207 1208 return err; 1209 } 1210 1211 /* 1212 * IPv4 request_sock destructor. 1213 */ 1214 static void tcp_v4_reqsk_destructor(struct request_sock *req) 1215 { 1216 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1)); 1217 } 1218 1219 #ifdef CONFIG_TCP_MD5SIG 1220 /* 1221 * RFC2385 MD5 checksumming requires a mapping of 1222 * IP address->MD5 Key. 1223 * We need to maintain these in the sk structure. 1224 */ 1225 1226 DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ); 1227 EXPORT_SYMBOL(tcp_md5_needed); 1228 1229 static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new) 1230 { 1231 if (!old) 1232 return true; 1233 1234 /* l3index always overrides non-l3index */ 1235 if (old->l3index && new->l3index == 0) 1236 return false; 1237 if (old->l3index == 0 && new->l3index) 1238 return true; 1239 1240 return old->prefixlen < new->prefixlen; 1241 } 1242 1243 /* Find the Key structure for an address. */ 1244 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1245 const union tcp_md5_addr *addr, 1246 int family, bool any_l3index) 1247 { 1248 const struct tcp_sock *tp = tcp_sk(sk); 1249 struct tcp_md5sig_key *key; 1250 const struct tcp_md5sig_info *md5sig; 1251 __be32 mask; 1252 struct tcp_md5sig_key *best_match = NULL; 1253 bool match; 1254 1255 /* caller either holds rcu_read_lock() or socket lock */ 1256 md5sig = rcu_dereference_check(tp->md5sig_info, 1257 lockdep_sock_is_held(sk)); 1258 if (!md5sig) 1259 return NULL; 1260 1261 hlist_for_each_entry_rcu(key, &md5sig->head, node, 1262 lockdep_sock_is_held(sk)) { 1263 if (key->family != family) 1264 continue; 1265 if (!any_l3index && key->flags & TCP_MD5SIG_FLAG_IFINDEX && 1266 key->l3index != l3index) 1267 continue; 1268 if (family == AF_INET) { 1269 mask = inet_make_mask(key->prefixlen); 1270 match = (key->addr.a4.s_addr & mask) == 1271 (addr->a4.s_addr & mask); 1272 #if IS_ENABLED(CONFIG_IPV6) 1273 } else if (family == AF_INET6) { 1274 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6, 1275 key->prefixlen); 1276 #endif 1277 } else { 1278 match = false; 1279 } 1280 1281 if (match && better_md5_match(best_match, key)) 1282 best_match = key; 1283 } 1284 return best_match; 1285 } 1286 EXPORT_SYMBOL(__tcp_md5_do_lookup); 1287 1288 static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk, 1289 const union tcp_md5_addr *addr, 1290 int family, u8 prefixlen, 1291 int l3index, u8 flags) 1292 { 1293 const struct tcp_sock *tp = tcp_sk(sk); 1294 struct tcp_md5sig_key *key; 1295 unsigned int size = sizeof(struct in_addr); 1296 const struct tcp_md5sig_info *md5sig; 1297 1298 /* caller either holds rcu_read_lock() or socket lock */ 1299 md5sig = rcu_dereference_check(tp->md5sig_info, 1300 lockdep_sock_is_held(sk)); 1301 if (!md5sig) 1302 return NULL; 1303 #if IS_ENABLED(CONFIG_IPV6) 1304 if (family == AF_INET6) 1305 size = sizeof(struct in6_addr); 1306 #endif 1307 hlist_for_each_entry_rcu(key, &md5sig->head, node, 1308 lockdep_sock_is_held(sk)) { 1309 if (key->family != family) 1310 continue; 1311 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX)) 1312 continue; 1313 if (key->l3index != l3index) 1314 continue; 1315 if (!memcmp(&key->addr, addr, size) && 1316 key->prefixlen == prefixlen) 1317 return key; 1318 } 1319 return NULL; 1320 } 1321 1322 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1323 const struct sock *addr_sk) 1324 { 1325 const union tcp_md5_addr *addr; 1326 int l3index; 1327 1328 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), 1329 addr_sk->sk_bound_dev_if); 1330 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr; 1331 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 1332 } 1333 EXPORT_SYMBOL(tcp_v4_md5_lookup); 1334 1335 static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp) 1336 { 1337 struct tcp_sock *tp = tcp_sk(sk); 1338 struct tcp_md5sig_info *md5sig; 1339 1340 md5sig = kmalloc(sizeof(*md5sig), gfp); 1341 if (!md5sig) 1342 return -ENOMEM; 1343 1344 sk_gso_disable(sk); 1345 INIT_HLIST_HEAD(&md5sig->head); 1346 rcu_assign_pointer(tp->md5sig_info, md5sig); 1347 return 0; 1348 } 1349 1350 /* This can be called on a newly created socket, from other files */ 1351 static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1352 int family, u8 prefixlen, int l3index, u8 flags, 1353 const u8 *newkey, u8 newkeylen, gfp_t gfp) 1354 { 1355 /* Add Key to the list */ 1356 struct tcp_md5sig_key *key; 1357 struct tcp_sock *tp = tcp_sk(sk); 1358 struct tcp_md5sig_info *md5sig; 1359 1360 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags); 1361 if (key) { 1362 /* Pre-existing entry - just update that one. 1363 * Note that the key might be used concurrently. 1364 * data_race() is telling kcsan that we do not care of 1365 * key mismatches, since changing MD5 key on live flows 1366 * can lead to packet drops. 1367 */ 1368 data_race(memcpy(key->key, newkey, newkeylen)); 1369 1370 /* Pairs with READ_ONCE() in tcp_md5_hash_key(). 1371 * Also note that a reader could catch new key->keylen value 1372 * but old key->key[], this is the reason we use __GFP_ZERO 1373 * at sock_kmalloc() time below these lines. 1374 */ 1375 WRITE_ONCE(key->keylen, newkeylen); 1376 1377 return 0; 1378 } 1379 1380 md5sig = rcu_dereference_protected(tp->md5sig_info, 1381 lockdep_sock_is_held(sk)); 1382 1383 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO); 1384 if (!key) 1385 return -ENOMEM; 1386 1387 memcpy(key->key, newkey, newkeylen); 1388 key->keylen = newkeylen; 1389 key->family = family; 1390 key->prefixlen = prefixlen; 1391 key->l3index = l3index; 1392 key->flags = flags; 1393 memcpy(&key->addr, addr, 1394 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) : 1395 sizeof(struct in_addr)); 1396 hlist_add_head_rcu(&key->node, &md5sig->head); 1397 return 0; 1398 } 1399 1400 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1401 int family, u8 prefixlen, int l3index, u8 flags, 1402 const u8 *newkey, u8 newkeylen) 1403 { 1404 struct tcp_sock *tp = tcp_sk(sk); 1405 1406 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) { 1407 if (tcp_md5_alloc_sigpool()) 1408 return -ENOMEM; 1409 1410 if (tcp_md5sig_info_add(sk, GFP_KERNEL)) { 1411 tcp_md5_release_sigpool(); 1412 return -ENOMEM; 1413 } 1414 1415 if (!static_branch_inc(&tcp_md5_needed.key)) { 1416 struct tcp_md5sig_info *md5sig; 1417 1418 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk)); 1419 rcu_assign_pointer(tp->md5sig_info, NULL); 1420 kfree_rcu(md5sig, rcu); 1421 tcp_md5_release_sigpool(); 1422 return -EUSERS; 1423 } 1424 } 1425 1426 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags, 1427 newkey, newkeylen, GFP_KERNEL); 1428 } 1429 EXPORT_SYMBOL(tcp_md5_do_add); 1430 1431 int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, 1432 int family, u8 prefixlen, int l3index, 1433 struct tcp_md5sig_key *key) 1434 { 1435 struct tcp_sock *tp = tcp_sk(sk); 1436 1437 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) { 1438 tcp_md5_add_sigpool(); 1439 1440 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) { 1441 tcp_md5_release_sigpool(); 1442 return -ENOMEM; 1443 } 1444 1445 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) { 1446 struct tcp_md5sig_info *md5sig; 1447 1448 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk)); 1449 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n"); 1450 rcu_assign_pointer(tp->md5sig_info, NULL); 1451 kfree_rcu(md5sig, rcu); 1452 tcp_md5_release_sigpool(); 1453 return -EUSERS; 1454 } 1455 } 1456 1457 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, 1458 key->flags, key->key, key->keylen, 1459 sk_gfp_mask(sk, GFP_ATOMIC)); 1460 } 1461 EXPORT_SYMBOL(tcp_md5_key_copy); 1462 1463 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family, 1464 u8 prefixlen, int l3index, u8 flags) 1465 { 1466 struct tcp_md5sig_key *key; 1467 1468 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags); 1469 if (!key) 1470 return -ENOENT; 1471 hlist_del_rcu(&key->node); 1472 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 1473 kfree_rcu(key, rcu); 1474 return 0; 1475 } 1476 EXPORT_SYMBOL(tcp_md5_do_del); 1477 1478 void tcp_clear_md5_list(struct sock *sk) 1479 { 1480 struct tcp_sock *tp = tcp_sk(sk); 1481 struct tcp_md5sig_key *key; 1482 struct hlist_node *n; 1483 struct tcp_md5sig_info *md5sig; 1484 1485 md5sig = rcu_dereference_protected(tp->md5sig_info, 1); 1486 1487 hlist_for_each_entry_safe(key, n, &md5sig->head, node) { 1488 hlist_del_rcu(&key->node); 1489 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 1490 kfree_rcu(key, rcu); 1491 } 1492 } 1493 1494 static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, 1495 sockptr_t optval, int optlen) 1496 { 1497 struct tcp_md5sig cmd; 1498 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr; 1499 const union tcp_md5_addr *addr; 1500 u8 prefixlen = 32; 1501 int l3index = 0; 1502 bool l3flag; 1503 u8 flags; 1504 1505 if (optlen < sizeof(cmd)) 1506 return -EINVAL; 1507 1508 if (copy_from_sockptr(&cmd, optval, sizeof(cmd))) 1509 return -EFAULT; 1510 1511 if (sin->sin_family != AF_INET) 1512 return -EINVAL; 1513 1514 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX; 1515 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX; 1516 1517 if (optname == TCP_MD5SIG_EXT && 1518 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) { 1519 prefixlen = cmd.tcpm_prefixlen; 1520 if (prefixlen > 32) 1521 return -EINVAL; 1522 } 1523 1524 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex && 1525 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) { 1526 struct net_device *dev; 1527 1528 rcu_read_lock(); 1529 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex); 1530 if (dev && netif_is_l3_master(dev)) 1531 l3index = dev->ifindex; 1532 1533 rcu_read_unlock(); 1534 1535 /* ok to reference set/not set outside of rcu; 1536 * right now device MUST be an L3 master 1537 */ 1538 if (!dev || !l3index) 1539 return -EINVAL; 1540 } 1541 1542 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr; 1543 1544 if (!cmd.tcpm_keylen) 1545 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags); 1546 1547 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) 1548 return -EINVAL; 1549 1550 /* Don't allow keys for peers that have a matching TCP-AO key. 1551 * See the comment in tcp_ao_add_cmd() 1552 */ 1553 if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false)) 1554 return -EKEYREJECTED; 1555 1556 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags, 1557 cmd.tcpm_key, cmd.tcpm_keylen); 1558 } 1559 1560 static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp, 1561 __be32 daddr, __be32 saddr, 1562 const struct tcphdr *th, int nbytes) 1563 { 1564 struct tcp4_pseudohdr *bp; 1565 struct scatterlist sg; 1566 struct tcphdr *_th; 1567 1568 bp = hp->scratch; 1569 bp->saddr = saddr; 1570 bp->daddr = daddr; 1571 bp->pad = 0; 1572 bp->protocol = IPPROTO_TCP; 1573 bp->len = cpu_to_be16(nbytes); 1574 1575 _th = (struct tcphdr *)(bp + 1); 1576 memcpy(_th, th, sizeof(*th)); 1577 _th->check = 0; 1578 1579 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th)); 1580 ahash_request_set_crypt(hp->req, &sg, NULL, 1581 sizeof(*bp) + sizeof(*th)); 1582 return crypto_ahash_update(hp->req); 1583 } 1584 1585 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 1586 __be32 daddr, __be32 saddr, const struct tcphdr *th) 1587 { 1588 struct tcp_sigpool hp; 1589 1590 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp)) 1591 goto clear_hash_nostart; 1592 1593 if (crypto_ahash_init(hp.req)) 1594 goto clear_hash; 1595 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2)) 1596 goto clear_hash; 1597 if (tcp_md5_hash_key(&hp, key)) 1598 goto clear_hash; 1599 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0); 1600 if (crypto_ahash_final(hp.req)) 1601 goto clear_hash; 1602 1603 tcp_sigpool_end(&hp); 1604 return 0; 1605 1606 clear_hash: 1607 tcp_sigpool_end(&hp); 1608 clear_hash_nostart: 1609 memset(md5_hash, 0, 16); 1610 return 1; 1611 } 1612 1613 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1614 const struct sock *sk, 1615 const struct sk_buff *skb) 1616 { 1617 const struct tcphdr *th = tcp_hdr(skb); 1618 struct tcp_sigpool hp; 1619 __be32 saddr, daddr; 1620 1621 if (sk) { /* valid for establish/request sockets */ 1622 saddr = sk->sk_rcv_saddr; 1623 daddr = sk->sk_daddr; 1624 } else { 1625 const struct iphdr *iph = ip_hdr(skb); 1626 saddr = iph->saddr; 1627 daddr = iph->daddr; 1628 } 1629 1630 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp)) 1631 goto clear_hash_nostart; 1632 1633 if (crypto_ahash_init(hp.req)) 1634 goto clear_hash; 1635 1636 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len)) 1637 goto clear_hash; 1638 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2)) 1639 goto clear_hash; 1640 if (tcp_md5_hash_key(&hp, key)) 1641 goto clear_hash; 1642 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0); 1643 if (crypto_ahash_final(hp.req)) 1644 goto clear_hash; 1645 1646 tcp_sigpool_end(&hp); 1647 return 0; 1648 1649 clear_hash: 1650 tcp_sigpool_end(&hp); 1651 clear_hash_nostart: 1652 memset(md5_hash, 0, 16); 1653 return 1; 1654 } 1655 EXPORT_SYMBOL(tcp_v4_md5_hash_skb); 1656 1657 #endif 1658 1659 static void tcp_v4_init_req(struct request_sock *req, 1660 const struct sock *sk_listener, 1661 struct sk_buff *skb) 1662 { 1663 struct inet_request_sock *ireq = inet_rsk(req); 1664 struct net *net = sock_net(sk_listener); 1665 1666 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr); 1667 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr); 1668 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb)); 1669 } 1670 1671 static struct dst_entry *tcp_v4_route_req(const struct sock *sk, 1672 struct sk_buff *skb, 1673 struct flowi *fl, 1674 struct request_sock *req, 1675 u32 tw_isn) 1676 { 1677 tcp_v4_init_req(req, sk, skb); 1678 1679 if (security_inet_conn_request(sk, skb, req)) 1680 return NULL; 1681 1682 return inet_csk_route_req(sk, &fl->u.ip4, req); 1683 } 1684 1685 struct request_sock_ops tcp_request_sock_ops __read_mostly = { 1686 .family = PF_INET, 1687 .obj_size = sizeof(struct tcp_request_sock), 1688 .rtx_syn_ack = tcp_rtx_synack, 1689 .send_ack = tcp_v4_reqsk_send_ack, 1690 .destructor = tcp_v4_reqsk_destructor, 1691 .send_reset = tcp_v4_send_reset, 1692 .syn_ack_timeout = tcp_syn_ack_timeout, 1693 }; 1694 1695 const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { 1696 .mss_clamp = TCP_MSS_DEFAULT, 1697 #ifdef CONFIG_TCP_MD5SIG 1698 .req_md5_lookup = tcp_v4_md5_lookup, 1699 .calc_md5_hash = tcp_v4_md5_hash_skb, 1700 #endif 1701 #ifdef CONFIG_TCP_AO 1702 .ao_lookup = tcp_v4_ao_lookup_rsk, 1703 .ao_calc_key = tcp_v4_ao_calc_key_rsk, 1704 .ao_synack_hash = tcp_v4_ao_synack_hash, 1705 #endif 1706 #ifdef CONFIG_SYN_COOKIES 1707 .cookie_init_seq = cookie_v4_init_sequence, 1708 #endif 1709 .route_req = tcp_v4_route_req, 1710 .init_seq = tcp_v4_init_seq, 1711 .init_ts_off = tcp_v4_init_ts_off, 1712 .send_synack = tcp_v4_send_synack, 1713 }; 1714 1715 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) 1716 { 1717 /* Never answer to SYNs send to broadcast or multicast */ 1718 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) 1719 goto drop; 1720 1721 return tcp_conn_request(&tcp_request_sock_ops, 1722 &tcp_request_sock_ipv4_ops, sk, skb); 1723 1724 drop: 1725 tcp_listendrop(sk); 1726 return 0; 1727 } 1728 EXPORT_SYMBOL(tcp_v4_conn_request); 1729 1730 1731 /* 1732 * The three way handshake has completed - we got a valid synack - 1733 * now create the new socket. 1734 */ 1735 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 1736 struct request_sock *req, 1737 struct dst_entry *dst, 1738 struct request_sock *req_unhash, 1739 bool *own_req) 1740 { 1741 struct inet_request_sock *ireq; 1742 bool found_dup_sk = false; 1743 struct inet_sock *newinet; 1744 struct tcp_sock *newtp; 1745 struct sock *newsk; 1746 #ifdef CONFIG_TCP_MD5SIG 1747 const union tcp_md5_addr *addr; 1748 struct tcp_md5sig_key *key; 1749 int l3index; 1750 #endif 1751 struct ip_options_rcu *inet_opt; 1752 1753 if (sk_acceptq_is_full(sk)) 1754 goto exit_overflow; 1755 1756 newsk = tcp_create_openreq_child(sk, req, skb); 1757 if (!newsk) 1758 goto exit_nonewsk; 1759 1760 newsk->sk_gso_type = SKB_GSO_TCPV4; 1761 inet_sk_rx_dst_set(newsk, skb); 1762 1763 newtp = tcp_sk(newsk); 1764 newinet = inet_sk(newsk); 1765 ireq = inet_rsk(req); 1766 sk_daddr_set(newsk, ireq->ir_rmt_addr); 1767 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr); 1768 newsk->sk_bound_dev_if = ireq->ir_iif; 1769 newinet->inet_saddr = ireq->ir_loc_addr; 1770 inet_opt = rcu_dereference(ireq->ireq_opt); 1771 RCU_INIT_POINTER(newinet->inet_opt, inet_opt); 1772 newinet->mc_index = inet_iif(skb); 1773 newinet->mc_ttl = ip_hdr(skb)->ttl; 1774 newinet->rcv_tos = ip_hdr(skb)->tos; 1775 inet_csk(newsk)->icsk_ext_hdr_len = 0; 1776 if (inet_opt) 1777 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; 1778 atomic_set(&newinet->inet_id, get_random_u16()); 1779 1780 /* Set ToS of the new socket based upon the value of incoming SYN. 1781 * ECT bits are set later in tcp_init_transfer(). 1782 */ 1783 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)) 1784 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK; 1785 1786 if (!dst) { 1787 dst = inet_csk_route_child_sock(sk, newsk, req); 1788 if (!dst) 1789 goto put_and_exit; 1790 } else { 1791 /* syncookie case : see end of cookie_v4_check() */ 1792 } 1793 sk_setup_caps(newsk, dst); 1794 1795 tcp_ca_openreq_child(newsk, dst); 1796 1797 tcp_sync_mss(newsk, dst_mtu(dst)); 1798 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst)); 1799 1800 tcp_initialize_rcv_mss(newsk); 1801 1802 #ifdef CONFIG_TCP_MD5SIG 1803 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif); 1804 /* Copy over the MD5 key from the original socket */ 1805 addr = (union tcp_md5_addr *)&newinet->inet_daddr; 1806 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 1807 if (key && !tcp_rsk_used_ao(req)) { 1808 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key)) 1809 goto put_and_exit; 1810 sk_gso_disable(newsk); 1811 } 1812 #endif 1813 #ifdef CONFIG_TCP_AO 1814 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET)) 1815 goto put_and_exit; /* OOM, release back memory */ 1816 #endif 1817 1818 if (__inet_inherit_port(sk, newsk) < 0) 1819 goto put_and_exit; 1820 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), 1821 &found_dup_sk); 1822 if (likely(*own_req)) { 1823 tcp_move_syn(newtp, req); 1824 ireq->ireq_opt = NULL; 1825 } else { 1826 newinet->inet_opt = NULL; 1827 1828 if (!req_unhash && found_dup_sk) { 1829 /* This code path should only be executed in the 1830 * syncookie case only 1831 */ 1832 bh_unlock_sock(newsk); 1833 sock_put(newsk); 1834 newsk = NULL; 1835 } 1836 } 1837 return newsk; 1838 1839 exit_overflow: 1840 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 1841 exit_nonewsk: 1842 dst_release(dst); 1843 exit: 1844 tcp_listendrop(sk); 1845 return NULL; 1846 put_and_exit: 1847 newinet->inet_opt = NULL; 1848 inet_csk_prepare_forced_close(newsk); 1849 tcp_done(newsk); 1850 goto exit; 1851 } 1852 EXPORT_SYMBOL(tcp_v4_syn_recv_sock); 1853 1854 static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb) 1855 { 1856 #ifdef CONFIG_SYN_COOKIES 1857 const struct tcphdr *th = tcp_hdr(skb); 1858 1859 if (!th->syn) 1860 sk = cookie_v4_check(sk, skb); 1861 #endif 1862 return sk; 1863 } 1864 1865 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 1866 struct tcphdr *th, u32 *cookie) 1867 { 1868 u16 mss = 0; 1869 #ifdef CONFIG_SYN_COOKIES 1870 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops, 1871 &tcp_request_sock_ipv4_ops, sk, th); 1872 if (mss) { 1873 *cookie = __cookie_v4_init_sequence(iph, th, &mss); 1874 tcp_synq_overflow(sk); 1875 } 1876 #endif 1877 return mss; 1878 } 1879 1880 INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *, 1881 u32)); 1882 /* The socket must have it's spinlock held when we get 1883 * here, unless it is a TCP_LISTEN socket. 1884 * 1885 * We have a potential double-lock case here, so even when 1886 * doing backlog processing we use the BH locking scheme. 1887 * This is because we cannot sleep with the original spinlock 1888 * held. 1889 */ 1890 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) 1891 { 1892 enum skb_drop_reason reason; 1893 struct sock *rsk; 1894 1895 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ 1896 struct dst_entry *dst; 1897 1898 dst = rcu_dereference_protected(sk->sk_rx_dst, 1899 lockdep_sock_is_held(sk)); 1900 1901 sock_rps_save_rxhash(sk, skb); 1902 sk_mark_napi_id(sk, skb); 1903 if (dst) { 1904 if (sk->sk_rx_dst_ifindex != skb->skb_iif || 1905 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check, 1906 dst, 0)) { 1907 RCU_INIT_POINTER(sk->sk_rx_dst, NULL); 1908 dst_release(dst); 1909 } 1910 } 1911 tcp_rcv_established(sk, skb); 1912 return 0; 1913 } 1914 1915 if (tcp_checksum_complete(skb)) 1916 goto csum_err; 1917 1918 if (sk->sk_state == TCP_LISTEN) { 1919 struct sock *nsk = tcp_v4_cookie_check(sk, skb); 1920 1921 if (!nsk) 1922 return 0; 1923 if (nsk != sk) { 1924 reason = tcp_child_process(sk, nsk, skb); 1925 if (reason) { 1926 rsk = nsk; 1927 goto reset; 1928 } 1929 return 0; 1930 } 1931 } else 1932 sock_rps_save_rxhash(sk, skb); 1933 1934 reason = tcp_rcv_state_process(sk, skb); 1935 if (reason) { 1936 rsk = sk; 1937 goto reset; 1938 } 1939 return 0; 1940 1941 reset: 1942 tcp_v4_send_reset(rsk, skb, sk_rst_convert_drop_reason(reason)); 1943 discard: 1944 sk_skb_reason_drop(sk, skb, reason); 1945 /* Be careful here. If this function gets more complicated and 1946 * gcc suffers from register pressure on the x86, sk (in %ebx) 1947 * might be destroyed here. This current version compiles correctly, 1948 * but you have been warned. 1949 */ 1950 return 0; 1951 1952 csum_err: 1953 reason = SKB_DROP_REASON_TCP_CSUM; 1954 trace_tcp_bad_csum(skb); 1955 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); 1956 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); 1957 goto discard; 1958 } 1959 EXPORT_SYMBOL(tcp_v4_do_rcv); 1960 1961 int tcp_v4_early_demux(struct sk_buff *skb) 1962 { 1963 struct net *net = dev_net(skb->dev); 1964 const struct iphdr *iph; 1965 const struct tcphdr *th; 1966 struct sock *sk; 1967 1968 if (skb->pkt_type != PACKET_HOST) 1969 return 0; 1970 1971 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr))) 1972 return 0; 1973 1974 iph = ip_hdr(skb); 1975 th = tcp_hdr(skb); 1976 1977 if (th->doff < sizeof(struct tcphdr) / 4) 1978 return 0; 1979 1980 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, 1981 iph->saddr, th->source, 1982 iph->daddr, ntohs(th->dest), 1983 skb->skb_iif, inet_sdif(skb)); 1984 if (sk) { 1985 skb->sk = sk; 1986 skb->destructor = sock_edemux; 1987 if (sk_fullsock(sk)) { 1988 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst); 1989 1990 if (dst) 1991 dst = dst_check(dst, 0); 1992 if (dst && 1993 sk->sk_rx_dst_ifindex == skb->skb_iif) 1994 skb_dst_set_noref(skb, dst); 1995 } 1996 } 1997 return 0; 1998 } 1999 2000 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, 2001 enum skb_drop_reason *reason) 2002 { 2003 u32 tail_gso_size, tail_gso_segs; 2004 struct skb_shared_info *shinfo; 2005 const struct tcphdr *th; 2006 struct tcphdr *thtail; 2007 struct sk_buff *tail; 2008 unsigned int hdrlen; 2009 bool fragstolen; 2010 u32 gso_segs; 2011 u32 gso_size; 2012 u64 limit; 2013 int delta; 2014 2015 /* In case all data was pulled from skb frags (in __pskb_pull_tail()), 2016 * we can fix skb->truesize to its real value to avoid future drops. 2017 * This is valid because skb is not yet charged to the socket. 2018 * It has been noticed pure SACK packets were sometimes dropped 2019 * (if cooked by drivers without copybreak feature). 2020 */ 2021 skb_condense(skb); 2022 2023 skb_dst_drop(skb); 2024 2025 if (unlikely(tcp_checksum_complete(skb))) { 2026 bh_unlock_sock(sk); 2027 trace_tcp_bad_csum(skb); 2028 *reason = SKB_DROP_REASON_TCP_CSUM; 2029 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); 2030 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); 2031 return true; 2032 } 2033 2034 /* Attempt coalescing to last skb in backlog, even if we are 2035 * above the limits. 2036 * This is okay because skb capacity is limited to MAX_SKB_FRAGS. 2037 */ 2038 th = (const struct tcphdr *)skb->data; 2039 hdrlen = th->doff * 4; 2040 2041 tail = sk->sk_backlog.tail; 2042 if (!tail) 2043 goto no_coalesce; 2044 thtail = (struct tcphdr *)tail->data; 2045 2046 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq || 2047 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield || 2048 ((TCP_SKB_CB(tail)->tcp_flags | 2049 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) || 2050 !((TCP_SKB_CB(tail)->tcp_flags & 2051 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) || 2052 ((TCP_SKB_CB(tail)->tcp_flags ^ 2053 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) || 2054 !tcp_skb_can_collapse_rx(tail, skb) || 2055 thtail->doff != th->doff || 2056 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th))) 2057 goto no_coalesce; 2058 2059 __skb_pull(skb, hdrlen); 2060 2061 shinfo = skb_shinfo(skb); 2062 gso_size = shinfo->gso_size ?: skb->len; 2063 gso_segs = shinfo->gso_segs ?: 1; 2064 2065 shinfo = skb_shinfo(tail); 2066 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen); 2067 tail_gso_segs = shinfo->gso_segs ?: 1; 2068 2069 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) { 2070 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq; 2071 2072 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) { 2073 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq; 2074 thtail->window = th->window; 2075 } 2076 2077 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and 2078 * thtail->fin, so that the fast path in tcp_rcv_established() 2079 * is not entered if we append a packet with a FIN. 2080 * SYN, RST, URG are not present. 2081 * ACK is set on both packets. 2082 * PSH : we do not really care in TCP stack, 2083 * at least for 'GRO' packets. 2084 */ 2085 thtail->fin |= th->fin; 2086 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags; 2087 2088 if (TCP_SKB_CB(skb)->has_rxtstamp) { 2089 TCP_SKB_CB(tail)->has_rxtstamp = true; 2090 tail->tstamp = skb->tstamp; 2091 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp; 2092 } 2093 2094 /* Not as strict as GRO. We only need to carry mss max value */ 2095 shinfo->gso_size = max(gso_size, tail_gso_size); 2096 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF); 2097 2098 sk->sk_backlog.len += delta; 2099 __NET_INC_STATS(sock_net(sk), 2100 LINUX_MIB_TCPBACKLOGCOALESCE); 2101 kfree_skb_partial(skb, fragstolen); 2102 return false; 2103 } 2104 __skb_push(skb, hdrlen); 2105 2106 no_coalesce: 2107 /* sk->sk_backlog.len is reset only at the end of __release_sock(). 2108 * Both sk->sk_backlog.len and sk->sk_rmem_alloc could reach 2109 * sk_rcvbuf in normal conditions. 2110 */ 2111 limit = ((u64)READ_ONCE(sk->sk_rcvbuf)) << 1; 2112 2113 limit += ((u32)READ_ONCE(sk->sk_sndbuf)) >> 1; 2114 2115 /* Only socket owner can try to collapse/prune rx queues 2116 * to reduce memory overhead, so add a little headroom here. 2117 * Few sockets backlog are possibly concurrently non empty. 2118 */ 2119 limit += 64 * 1024; 2120 2121 limit = min_t(u64, limit, UINT_MAX); 2122 2123 if (unlikely(sk_add_backlog(sk, skb, limit))) { 2124 bh_unlock_sock(sk); 2125 *reason = SKB_DROP_REASON_SOCKET_BACKLOG; 2126 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP); 2127 return true; 2128 } 2129 return false; 2130 } 2131 EXPORT_SYMBOL(tcp_add_backlog); 2132 2133 int tcp_filter(struct sock *sk, struct sk_buff *skb) 2134 { 2135 struct tcphdr *th = (struct tcphdr *)skb->data; 2136 2137 return sk_filter_trim_cap(sk, skb, th->doff * 4); 2138 } 2139 EXPORT_SYMBOL(tcp_filter); 2140 2141 static void tcp_v4_restore_cb(struct sk_buff *skb) 2142 { 2143 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4, 2144 sizeof(struct inet_skb_parm)); 2145 } 2146 2147 static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph, 2148 const struct tcphdr *th) 2149 { 2150 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB() 2151 * barrier() makes sure compiler wont play fool^Waliasing games. 2152 */ 2153 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb), 2154 sizeof(struct inet_skb_parm)); 2155 barrier(); 2156 2157 TCP_SKB_CB(skb)->seq = ntohl(th->seq); 2158 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + 2159 skb->len - th->doff * 4); 2160 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); 2161 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th); 2162 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph); 2163 TCP_SKB_CB(skb)->sacked = 0; 2164 TCP_SKB_CB(skb)->has_rxtstamp = 2165 skb->tstamp || skb_hwtstamps(skb)->hwtstamp; 2166 } 2167 2168 /* 2169 * From tcp_input.c 2170 */ 2171 2172 int tcp_v4_rcv(struct sk_buff *skb) 2173 { 2174 struct net *net = dev_net(skb->dev); 2175 enum skb_drop_reason drop_reason; 2176 int sdif = inet_sdif(skb); 2177 int dif = inet_iif(skb); 2178 const struct iphdr *iph; 2179 const struct tcphdr *th; 2180 struct sock *sk = NULL; 2181 bool refcounted; 2182 int ret; 2183 u32 isn; 2184 2185 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; 2186 if (skb->pkt_type != PACKET_HOST) 2187 goto discard_it; 2188 2189 /* Count it even if it's bad */ 2190 __TCP_INC_STATS(net, TCP_MIB_INSEGS); 2191 2192 if (!pskb_may_pull(skb, sizeof(struct tcphdr))) 2193 goto discard_it; 2194 2195 th = (const struct tcphdr *)skb->data; 2196 2197 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) { 2198 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL; 2199 goto bad_packet; 2200 } 2201 if (!pskb_may_pull(skb, th->doff * 4)) 2202 goto discard_it; 2203 2204 /* An explanation is required here, I think. 2205 * Packet length and doff are validated by header prediction, 2206 * provided case of th->doff==0 is eliminated. 2207 * So, we defer the checks. */ 2208 2209 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo)) 2210 goto csum_error; 2211 2212 th = (const struct tcphdr *)skb->data; 2213 iph = ip_hdr(skb); 2214 lookup: 2215 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo, 2216 skb, __tcp_hdrlen(th), th->source, 2217 th->dest, sdif, &refcounted); 2218 if (!sk) 2219 goto no_tcp_socket; 2220 2221 if (sk->sk_state == TCP_TIME_WAIT) 2222 goto do_time_wait; 2223 2224 if (sk->sk_state == TCP_NEW_SYN_RECV) { 2225 struct request_sock *req = inet_reqsk(sk); 2226 bool req_stolen = false; 2227 struct sock *nsk; 2228 2229 sk = req->rsk_listener; 2230 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 2231 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 2232 else 2233 drop_reason = tcp_inbound_hash(sk, req, skb, 2234 &iph->saddr, &iph->daddr, 2235 AF_INET, dif, sdif); 2236 if (unlikely(drop_reason)) { 2237 sk_drops_add(sk, skb); 2238 reqsk_put(req); 2239 goto discard_it; 2240 } 2241 if (tcp_checksum_complete(skb)) { 2242 reqsk_put(req); 2243 goto csum_error; 2244 } 2245 if (unlikely(sk->sk_state != TCP_LISTEN)) { 2246 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb); 2247 if (!nsk) { 2248 inet_csk_reqsk_queue_drop_and_put(sk, req); 2249 goto lookup; 2250 } 2251 sk = nsk; 2252 /* reuseport_migrate_sock() has already held one sk_refcnt 2253 * before returning. 2254 */ 2255 } else { 2256 /* We own a reference on the listener, increase it again 2257 * as we might lose it too soon. 2258 */ 2259 sock_hold(sk); 2260 } 2261 refcounted = true; 2262 nsk = NULL; 2263 if (!tcp_filter(sk, skb)) { 2264 th = (const struct tcphdr *)skb->data; 2265 iph = ip_hdr(skb); 2266 tcp_v4_fill_cb(skb, iph, th); 2267 nsk = tcp_check_req(sk, skb, req, false, &req_stolen); 2268 } else { 2269 drop_reason = SKB_DROP_REASON_SOCKET_FILTER; 2270 } 2271 if (!nsk) { 2272 reqsk_put(req); 2273 if (req_stolen) { 2274 /* Another cpu got exclusive access to req 2275 * and created a full blown socket. 2276 * Try to feed this packet to this socket 2277 * instead of discarding it. 2278 */ 2279 tcp_v4_restore_cb(skb); 2280 sock_put(sk); 2281 goto lookup; 2282 } 2283 goto discard_and_relse; 2284 } 2285 nf_reset_ct(skb); 2286 if (nsk == sk) { 2287 reqsk_put(req); 2288 tcp_v4_restore_cb(skb); 2289 } else { 2290 drop_reason = tcp_child_process(sk, nsk, skb); 2291 if (drop_reason) { 2292 enum sk_rst_reason rst_reason; 2293 2294 rst_reason = sk_rst_convert_drop_reason(drop_reason); 2295 tcp_v4_send_reset(nsk, skb, rst_reason); 2296 goto discard_and_relse; 2297 } 2298 sock_put(sk); 2299 return 0; 2300 } 2301 } 2302 2303 process: 2304 if (static_branch_unlikely(&ip4_min_ttl)) { 2305 /* min_ttl can be changed concurrently from do_ip_setsockopt() */ 2306 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) { 2307 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); 2308 drop_reason = SKB_DROP_REASON_TCP_MINTTL; 2309 goto discard_and_relse; 2310 } 2311 } 2312 2313 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) { 2314 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 2315 goto discard_and_relse; 2316 } 2317 2318 drop_reason = tcp_inbound_hash(sk, NULL, skb, &iph->saddr, &iph->daddr, 2319 AF_INET, dif, sdif); 2320 if (drop_reason) 2321 goto discard_and_relse; 2322 2323 nf_reset_ct(skb); 2324 2325 if (tcp_filter(sk, skb)) { 2326 drop_reason = SKB_DROP_REASON_SOCKET_FILTER; 2327 goto discard_and_relse; 2328 } 2329 th = (const struct tcphdr *)skb->data; 2330 iph = ip_hdr(skb); 2331 tcp_v4_fill_cb(skb, iph, th); 2332 2333 skb->dev = NULL; 2334 2335 if (sk->sk_state == TCP_LISTEN) { 2336 ret = tcp_v4_do_rcv(sk, skb); 2337 goto put_and_return; 2338 } 2339 2340 sk_incoming_cpu_update(sk); 2341 2342 bh_lock_sock_nested(sk); 2343 tcp_segs_in(tcp_sk(sk), skb); 2344 ret = 0; 2345 if (!sock_owned_by_user(sk)) { 2346 ret = tcp_v4_do_rcv(sk, skb); 2347 } else { 2348 if (tcp_add_backlog(sk, skb, &drop_reason)) 2349 goto discard_and_relse; 2350 } 2351 bh_unlock_sock(sk); 2352 2353 put_and_return: 2354 if (refcounted) 2355 sock_put(sk); 2356 2357 return ret; 2358 2359 no_tcp_socket: 2360 drop_reason = SKB_DROP_REASON_NO_SOCKET; 2361 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 2362 goto discard_it; 2363 2364 tcp_v4_fill_cb(skb, iph, th); 2365 2366 if (tcp_checksum_complete(skb)) { 2367 csum_error: 2368 drop_reason = SKB_DROP_REASON_TCP_CSUM; 2369 trace_tcp_bad_csum(skb); 2370 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS); 2371 bad_packet: 2372 __TCP_INC_STATS(net, TCP_MIB_INERRS); 2373 } else { 2374 tcp_v4_send_reset(NULL, skb, sk_rst_convert_drop_reason(drop_reason)); 2375 } 2376 2377 discard_it: 2378 SKB_DR_OR(drop_reason, NOT_SPECIFIED); 2379 /* Discard frame. */ 2380 sk_skb_reason_drop(sk, skb, drop_reason); 2381 return 0; 2382 2383 discard_and_relse: 2384 sk_drops_add(sk, skb); 2385 if (refcounted) 2386 sock_put(sk); 2387 goto discard_it; 2388 2389 do_time_wait: 2390 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 2391 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 2392 inet_twsk_put(inet_twsk(sk)); 2393 goto discard_it; 2394 } 2395 2396 tcp_v4_fill_cb(skb, iph, th); 2397 2398 if (tcp_checksum_complete(skb)) { 2399 inet_twsk_put(inet_twsk(sk)); 2400 goto csum_error; 2401 } 2402 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn)) { 2403 case TCP_TW_SYN: { 2404 struct sock *sk2 = inet_lookup_listener(net, 2405 net->ipv4.tcp_death_row.hashinfo, 2406 skb, __tcp_hdrlen(th), 2407 iph->saddr, th->source, 2408 iph->daddr, th->dest, 2409 inet_iif(skb), 2410 sdif); 2411 if (sk2) { 2412 inet_twsk_deschedule_put(inet_twsk(sk)); 2413 sk = sk2; 2414 tcp_v4_restore_cb(skb); 2415 refcounted = false; 2416 __this_cpu_write(tcp_tw_isn, isn); 2417 goto process; 2418 } 2419 } 2420 /* to ACK */ 2421 fallthrough; 2422 case TCP_TW_ACK: 2423 tcp_v4_timewait_ack(sk, skb); 2424 break; 2425 case TCP_TW_RST: 2426 tcp_v4_send_reset(sk, skb, SK_RST_REASON_TCP_TIMEWAIT_SOCKET); 2427 inet_twsk_deschedule_put(inet_twsk(sk)); 2428 goto discard_it; 2429 case TCP_TW_SUCCESS:; 2430 } 2431 goto discard_it; 2432 } 2433 2434 static struct timewait_sock_ops tcp_timewait_sock_ops = { 2435 .twsk_obj_size = sizeof(struct tcp_timewait_sock), 2436 .twsk_destructor= tcp_twsk_destructor, 2437 }; 2438 2439 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) 2440 { 2441 struct dst_entry *dst = skb_dst(skb); 2442 2443 if (dst && dst_hold_safe(dst)) { 2444 rcu_assign_pointer(sk->sk_rx_dst, dst); 2445 sk->sk_rx_dst_ifindex = skb->skb_iif; 2446 } 2447 } 2448 EXPORT_SYMBOL(inet_sk_rx_dst_set); 2449 2450 const struct inet_connection_sock_af_ops ipv4_specific = { 2451 .queue_xmit = ip_queue_xmit, 2452 .send_check = tcp_v4_send_check, 2453 .rebuild_header = inet_sk_rebuild_header, 2454 .sk_rx_dst_set = inet_sk_rx_dst_set, 2455 .conn_request = tcp_v4_conn_request, 2456 .syn_recv_sock = tcp_v4_syn_recv_sock, 2457 .net_header_len = sizeof(struct iphdr), 2458 .setsockopt = ip_setsockopt, 2459 .getsockopt = ip_getsockopt, 2460 .addr2sockaddr = inet_csk_addr2sockaddr, 2461 .sockaddr_len = sizeof(struct sockaddr_in), 2462 .mtu_reduced = tcp_v4_mtu_reduced, 2463 }; 2464 EXPORT_SYMBOL(ipv4_specific); 2465 2466 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) 2467 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = { 2468 #ifdef CONFIG_TCP_MD5SIG 2469 .md5_lookup = tcp_v4_md5_lookup, 2470 .calc_md5_hash = tcp_v4_md5_hash_skb, 2471 .md5_parse = tcp_v4_parse_md5_keys, 2472 #endif 2473 #ifdef CONFIG_TCP_AO 2474 .ao_lookup = tcp_v4_ao_lookup, 2475 .calc_ao_hash = tcp_v4_ao_hash_skb, 2476 .ao_parse = tcp_v4_parse_ao, 2477 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk, 2478 #endif 2479 }; 2480 #endif 2481 2482 /* NOTE: A lot of things set to zero explicitly by call to 2483 * sk_alloc() so need not be done here. 2484 */ 2485 static int tcp_v4_init_sock(struct sock *sk) 2486 { 2487 struct inet_connection_sock *icsk = inet_csk(sk); 2488 2489 tcp_init_sock(sk); 2490 2491 icsk->icsk_af_ops = &ipv4_specific; 2492 2493 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) 2494 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific; 2495 #endif 2496 2497 return 0; 2498 } 2499 2500 #ifdef CONFIG_TCP_MD5SIG 2501 static void tcp_md5sig_info_free_rcu(struct rcu_head *head) 2502 { 2503 struct tcp_md5sig_info *md5sig; 2504 2505 md5sig = container_of(head, struct tcp_md5sig_info, rcu); 2506 kfree(md5sig); 2507 static_branch_slow_dec_deferred(&tcp_md5_needed); 2508 tcp_md5_release_sigpool(); 2509 } 2510 #endif 2511 2512 void tcp_v4_destroy_sock(struct sock *sk) 2513 { 2514 struct tcp_sock *tp = tcp_sk(sk); 2515 2516 trace_tcp_destroy_sock(sk); 2517 2518 tcp_clear_xmit_timers(sk); 2519 2520 tcp_cleanup_congestion_control(sk); 2521 2522 tcp_cleanup_ulp(sk); 2523 2524 /* Cleanup up the write buffer. */ 2525 tcp_write_queue_purge(sk); 2526 2527 /* Check if we want to disable active TFO */ 2528 tcp_fastopen_active_disable_ofo_check(sk); 2529 2530 /* Cleans up our, hopefully empty, out_of_order_queue. */ 2531 skb_rbtree_purge(&tp->out_of_order_queue); 2532 2533 #ifdef CONFIG_TCP_MD5SIG 2534 /* Clean up the MD5 key list, if any */ 2535 if (tp->md5sig_info) { 2536 struct tcp_md5sig_info *md5sig; 2537 2538 md5sig = rcu_dereference_protected(tp->md5sig_info, 1); 2539 tcp_clear_md5_list(sk); 2540 call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu); 2541 rcu_assign_pointer(tp->md5sig_info, NULL); 2542 } 2543 #endif 2544 tcp_ao_destroy_sock(sk, false); 2545 2546 /* Clean up a referenced TCP bind bucket. */ 2547 if (inet_csk(sk)->icsk_bind_hash) 2548 inet_put_port(sk); 2549 2550 BUG_ON(rcu_access_pointer(tp->fastopen_rsk)); 2551 2552 /* If socket is aborted during connect operation */ 2553 tcp_free_fastopen_req(tp); 2554 tcp_fastopen_destroy_cipher(sk); 2555 tcp_saved_syn_free(tp); 2556 2557 sk_sockets_allocated_dec(sk); 2558 } 2559 EXPORT_SYMBOL(tcp_v4_destroy_sock); 2560 2561 #ifdef CONFIG_PROC_FS 2562 /* Proc filesystem TCP sock list dumping. */ 2563 2564 static unsigned short seq_file_family(const struct seq_file *seq); 2565 2566 static bool seq_sk_match(struct seq_file *seq, const struct sock *sk) 2567 { 2568 unsigned short family = seq_file_family(seq); 2569 2570 /* AF_UNSPEC is used as a match all */ 2571 return ((family == AF_UNSPEC || family == sk->sk_family) && 2572 net_eq(sock_net(sk), seq_file_net(seq))); 2573 } 2574 2575 /* Find a non empty bucket (starting from st->bucket) 2576 * and return the first sk from it. 2577 */ 2578 static void *listening_get_first(struct seq_file *seq) 2579 { 2580 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2581 struct tcp_iter_state *st = seq->private; 2582 2583 st->offset = 0; 2584 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) { 2585 struct inet_listen_hashbucket *ilb2; 2586 struct hlist_nulls_node *node; 2587 struct sock *sk; 2588 2589 ilb2 = &hinfo->lhash2[st->bucket]; 2590 if (hlist_nulls_empty(&ilb2->nulls_head)) 2591 continue; 2592 2593 spin_lock(&ilb2->lock); 2594 sk_nulls_for_each(sk, node, &ilb2->nulls_head) { 2595 if (seq_sk_match(seq, sk)) 2596 return sk; 2597 } 2598 spin_unlock(&ilb2->lock); 2599 } 2600 2601 return NULL; 2602 } 2603 2604 /* Find the next sk of "cur" within the same bucket (i.e. st->bucket). 2605 * If "cur" is the last one in the st->bucket, 2606 * call listening_get_first() to return the first sk of the next 2607 * non empty bucket. 2608 */ 2609 static void *listening_get_next(struct seq_file *seq, void *cur) 2610 { 2611 struct tcp_iter_state *st = seq->private; 2612 struct inet_listen_hashbucket *ilb2; 2613 struct hlist_nulls_node *node; 2614 struct inet_hashinfo *hinfo; 2615 struct sock *sk = cur; 2616 2617 ++st->num; 2618 ++st->offset; 2619 2620 sk = sk_nulls_next(sk); 2621 sk_nulls_for_each_from(sk, node) { 2622 if (seq_sk_match(seq, sk)) 2623 return sk; 2624 } 2625 2626 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2627 ilb2 = &hinfo->lhash2[st->bucket]; 2628 spin_unlock(&ilb2->lock); 2629 ++st->bucket; 2630 return listening_get_first(seq); 2631 } 2632 2633 static void *listening_get_idx(struct seq_file *seq, loff_t *pos) 2634 { 2635 struct tcp_iter_state *st = seq->private; 2636 void *rc; 2637 2638 st->bucket = 0; 2639 st->offset = 0; 2640 rc = listening_get_first(seq); 2641 2642 while (rc && *pos) { 2643 rc = listening_get_next(seq, rc); 2644 --*pos; 2645 } 2646 return rc; 2647 } 2648 2649 static inline bool empty_bucket(struct inet_hashinfo *hinfo, 2650 const struct tcp_iter_state *st) 2651 { 2652 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain); 2653 } 2654 2655 /* 2656 * Get first established socket starting from bucket given in st->bucket. 2657 * If st->bucket is zero, the very first socket in the hash is returned. 2658 */ 2659 static void *established_get_first(struct seq_file *seq) 2660 { 2661 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2662 struct tcp_iter_state *st = seq->private; 2663 2664 st->offset = 0; 2665 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) { 2666 struct sock *sk; 2667 struct hlist_nulls_node *node; 2668 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket); 2669 2670 cond_resched(); 2671 2672 /* Lockless fast path for the common case of empty buckets */ 2673 if (empty_bucket(hinfo, st)) 2674 continue; 2675 2676 spin_lock_bh(lock); 2677 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) { 2678 if (seq_sk_match(seq, sk)) 2679 return sk; 2680 } 2681 spin_unlock_bh(lock); 2682 } 2683 2684 return NULL; 2685 } 2686 2687 static void *established_get_next(struct seq_file *seq, void *cur) 2688 { 2689 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2690 struct tcp_iter_state *st = seq->private; 2691 struct hlist_nulls_node *node; 2692 struct sock *sk = cur; 2693 2694 ++st->num; 2695 ++st->offset; 2696 2697 sk = sk_nulls_next(sk); 2698 2699 sk_nulls_for_each_from(sk, node) { 2700 if (seq_sk_match(seq, sk)) 2701 return sk; 2702 } 2703 2704 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket)); 2705 ++st->bucket; 2706 return established_get_first(seq); 2707 } 2708 2709 static void *established_get_idx(struct seq_file *seq, loff_t pos) 2710 { 2711 struct tcp_iter_state *st = seq->private; 2712 void *rc; 2713 2714 st->bucket = 0; 2715 rc = established_get_first(seq); 2716 2717 while (rc && pos) { 2718 rc = established_get_next(seq, rc); 2719 --pos; 2720 } 2721 return rc; 2722 } 2723 2724 static void *tcp_get_idx(struct seq_file *seq, loff_t pos) 2725 { 2726 void *rc; 2727 struct tcp_iter_state *st = seq->private; 2728 2729 st->state = TCP_SEQ_STATE_LISTENING; 2730 rc = listening_get_idx(seq, &pos); 2731 2732 if (!rc) { 2733 st->state = TCP_SEQ_STATE_ESTABLISHED; 2734 rc = established_get_idx(seq, pos); 2735 } 2736 2737 return rc; 2738 } 2739 2740 static void *tcp_seek_last_pos(struct seq_file *seq) 2741 { 2742 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2743 struct tcp_iter_state *st = seq->private; 2744 int bucket = st->bucket; 2745 int offset = st->offset; 2746 int orig_num = st->num; 2747 void *rc = NULL; 2748 2749 switch (st->state) { 2750 case TCP_SEQ_STATE_LISTENING: 2751 if (st->bucket > hinfo->lhash2_mask) 2752 break; 2753 rc = listening_get_first(seq); 2754 while (offset-- && rc && bucket == st->bucket) 2755 rc = listening_get_next(seq, rc); 2756 if (rc) 2757 break; 2758 st->bucket = 0; 2759 st->state = TCP_SEQ_STATE_ESTABLISHED; 2760 fallthrough; 2761 case TCP_SEQ_STATE_ESTABLISHED: 2762 if (st->bucket > hinfo->ehash_mask) 2763 break; 2764 rc = established_get_first(seq); 2765 while (offset-- && rc && bucket == st->bucket) 2766 rc = established_get_next(seq, rc); 2767 } 2768 2769 st->num = orig_num; 2770 2771 return rc; 2772 } 2773 2774 void *tcp_seq_start(struct seq_file *seq, loff_t *pos) 2775 { 2776 struct tcp_iter_state *st = seq->private; 2777 void *rc; 2778 2779 if (*pos && *pos == st->last_pos) { 2780 rc = tcp_seek_last_pos(seq); 2781 if (rc) 2782 goto out; 2783 } 2784 2785 st->state = TCP_SEQ_STATE_LISTENING; 2786 st->num = 0; 2787 st->bucket = 0; 2788 st->offset = 0; 2789 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; 2790 2791 out: 2792 st->last_pos = *pos; 2793 return rc; 2794 } 2795 EXPORT_SYMBOL(tcp_seq_start); 2796 2797 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2798 { 2799 struct tcp_iter_state *st = seq->private; 2800 void *rc = NULL; 2801 2802 if (v == SEQ_START_TOKEN) { 2803 rc = tcp_get_idx(seq, 0); 2804 goto out; 2805 } 2806 2807 switch (st->state) { 2808 case TCP_SEQ_STATE_LISTENING: 2809 rc = listening_get_next(seq, v); 2810 if (!rc) { 2811 st->state = TCP_SEQ_STATE_ESTABLISHED; 2812 st->bucket = 0; 2813 st->offset = 0; 2814 rc = established_get_first(seq); 2815 } 2816 break; 2817 case TCP_SEQ_STATE_ESTABLISHED: 2818 rc = established_get_next(seq, v); 2819 break; 2820 } 2821 out: 2822 ++*pos; 2823 st->last_pos = *pos; 2824 return rc; 2825 } 2826 EXPORT_SYMBOL(tcp_seq_next); 2827 2828 void tcp_seq_stop(struct seq_file *seq, void *v) 2829 { 2830 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2831 struct tcp_iter_state *st = seq->private; 2832 2833 switch (st->state) { 2834 case TCP_SEQ_STATE_LISTENING: 2835 if (v != SEQ_START_TOKEN) 2836 spin_unlock(&hinfo->lhash2[st->bucket].lock); 2837 break; 2838 case TCP_SEQ_STATE_ESTABLISHED: 2839 if (v) 2840 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket)); 2841 break; 2842 } 2843 } 2844 EXPORT_SYMBOL(tcp_seq_stop); 2845 2846 static void get_openreq4(const struct request_sock *req, 2847 struct seq_file *f, int i) 2848 { 2849 const struct inet_request_sock *ireq = inet_rsk(req); 2850 long delta = req->rsk_timer.expires - jiffies; 2851 2852 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2853 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK", 2854 i, 2855 ireq->ir_loc_addr, 2856 ireq->ir_num, 2857 ireq->ir_rmt_addr, 2858 ntohs(ireq->ir_rmt_port), 2859 TCP_SYN_RECV, 2860 0, 0, /* could print option size, but that is af dependent. */ 2861 1, /* timers active (only the expire timer) */ 2862 jiffies_delta_to_clock_t(delta), 2863 req->num_timeout, 2864 from_kuid_munged(seq_user_ns(f), 2865 sock_i_uid(req->rsk_listener)), 2866 0, /* non standard timer */ 2867 0, /* open_requests have no inode */ 2868 0, 2869 req); 2870 } 2871 2872 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i) 2873 { 2874 int timer_active; 2875 unsigned long timer_expires; 2876 const struct tcp_sock *tp = tcp_sk(sk); 2877 const struct inet_connection_sock *icsk = inet_csk(sk); 2878 const struct inet_sock *inet = inet_sk(sk); 2879 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq; 2880 __be32 dest = inet->inet_daddr; 2881 __be32 src = inet->inet_rcv_saddr; 2882 __u16 destp = ntohs(inet->inet_dport); 2883 __u16 srcp = ntohs(inet->inet_sport); 2884 int rx_queue; 2885 int state; 2886 2887 if (icsk->icsk_pending == ICSK_TIME_RETRANS || 2888 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT || 2889 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { 2890 timer_active = 1; 2891 timer_expires = icsk->icsk_timeout; 2892 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { 2893 timer_active = 4; 2894 timer_expires = icsk->icsk_timeout; 2895 } else if (timer_pending(&sk->sk_timer)) { 2896 timer_active = 2; 2897 timer_expires = sk->sk_timer.expires; 2898 } else { 2899 timer_active = 0; 2900 timer_expires = jiffies; 2901 } 2902 2903 state = inet_sk_state_load(sk); 2904 if (state == TCP_LISTEN) 2905 rx_queue = READ_ONCE(sk->sk_ack_backlog); 2906 else 2907 /* Because we don't lock the socket, 2908 * we might find a transient negative value. 2909 */ 2910 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) - 2911 READ_ONCE(tp->copied_seq), 0); 2912 2913 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " 2914 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d", 2915 i, src, srcp, dest, destp, state, 2916 READ_ONCE(tp->write_seq) - tp->snd_una, 2917 rx_queue, 2918 timer_active, 2919 jiffies_delta_to_clock_t(timer_expires - jiffies), 2920 icsk->icsk_retransmits, 2921 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)), 2922 icsk->icsk_probes_out, 2923 sock_i_ino(sk), 2924 refcount_read(&sk->sk_refcnt), sk, 2925 jiffies_to_clock_t(icsk->icsk_rto), 2926 jiffies_to_clock_t(icsk->icsk_ack.ato), 2927 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk), 2928 tcp_snd_cwnd(tp), 2929 state == TCP_LISTEN ? 2930 fastopenq->max_qlen : 2931 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)); 2932 } 2933 2934 static void get_timewait4_sock(const struct inet_timewait_sock *tw, 2935 struct seq_file *f, int i) 2936 { 2937 long delta = tw->tw_timer.expires - jiffies; 2938 __be32 dest, src; 2939 __u16 destp, srcp; 2940 2941 dest = tw->tw_daddr; 2942 src = tw->tw_rcv_saddr; 2943 destp = ntohs(tw->tw_dport); 2944 srcp = ntohs(tw->tw_sport); 2945 2946 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2947 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK", 2948 i, src, srcp, dest, destp, tw->tw_substate, 0, 0, 2949 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, 2950 refcount_read(&tw->tw_refcnt), tw); 2951 } 2952 2953 #define TMPSZ 150 2954 2955 static int tcp4_seq_show(struct seq_file *seq, void *v) 2956 { 2957 struct tcp_iter_state *st; 2958 struct sock *sk = v; 2959 2960 seq_setwidth(seq, TMPSZ - 1); 2961 if (v == SEQ_START_TOKEN) { 2962 seq_puts(seq, " sl local_address rem_address st tx_queue " 2963 "rx_queue tr tm->when retrnsmt uid timeout " 2964 "inode"); 2965 goto out; 2966 } 2967 st = seq->private; 2968 2969 if (sk->sk_state == TCP_TIME_WAIT) 2970 get_timewait4_sock(v, seq, st->num); 2971 else if (sk->sk_state == TCP_NEW_SYN_RECV) 2972 get_openreq4(v, seq, st->num); 2973 else 2974 get_tcp4_sock(v, seq, st->num); 2975 out: 2976 seq_pad(seq, '\n'); 2977 return 0; 2978 } 2979 2980 #ifdef CONFIG_BPF_SYSCALL 2981 struct bpf_tcp_iter_state { 2982 struct tcp_iter_state state; 2983 unsigned int cur_sk; 2984 unsigned int end_sk; 2985 unsigned int max_sk; 2986 struct sock **batch; 2987 bool st_bucket_done; 2988 }; 2989 2990 struct bpf_iter__tcp { 2991 __bpf_md_ptr(struct bpf_iter_meta *, meta); 2992 __bpf_md_ptr(struct sock_common *, sk_common); 2993 uid_t uid __aligned(8); 2994 }; 2995 2996 static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta, 2997 struct sock_common *sk_common, uid_t uid) 2998 { 2999 struct bpf_iter__tcp ctx; 3000 3001 meta->seq_num--; /* skip SEQ_START_TOKEN */ 3002 ctx.meta = meta; 3003 ctx.sk_common = sk_common; 3004 ctx.uid = uid; 3005 return bpf_iter_run_prog(prog, &ctx); 3006 } 3007 3008 static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter) 3009 { 3010 while (iter->cur_sk < iter->end_sk) 3011 sock_gen_put(iter->batch[iter->cur_sk++]); 3012 } 3013 3014 static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter, 3015 unsigned int new_batch_sz) 3016 { 3017 struct sock **new_batch; 3018 3019 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz, 3020 GFP_USER | __GFP_NOWARN); 3021 if (!new_batch) 3022 return -ENOMEM; 3023 3024 bpf_iter_tcp_put_batch(iter); 3025 kvfree(iter->batch); 3026 iter->batch = new_batch; 3027 iter->max_sk = new_batch_sz; 3028 3029 return 0; 3030 } 3031 3032 static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq, 3033 struct sock *start_sk) 3034 { 3035 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 3036 struct bpf_tcp_iter_state *iter = seq->private; 3037 struct tcp_iter_state *st = &iter->state; 3038 struct hlist_nulls_node *node; 3039 unsigned int expected = 1; 3040 struct sock *sk; 3041 3042 sock_hold(start_sk); 3043 iter->batch[iter->end_sk++] = start_sk; 3044 3045 sk = sk_nulls_next(start_sk); 3046 sk_nulls_for_each_from(sk, node) { 3047 if (seq_sk_match(seq, sk)) { 3048 if (iter->end_sk < iter->max_sk) { 3049 sock_hold(sk); 3050 iter->batch[iter->end_sk++] = sk; 3051 } 3052 expected++; 3053 } 3054 } 3055 spin_unlock(&hinfo->lhash2[st->bucket].lock); 3056 3057 return expected; 3058 } 3059 3060 static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq, 3061 struct sock *start_sk) 3062 { 3063 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 3064 struct bpf_tcp_iter_state *iter = seq->private; 3065 struct tcp_iter_state *st = &iter->state; 3066 struct hlist_nulls_node *node; 3067 unsigned int expected = 1; 3068 struct sock *sk; 3069 3070 sock_hold(start_sk); 3071 iter->batch[iter->end_sk++] = start_sk; 3072 3073 sk = sk_nulls_next(start_sk); 3074 sk_nulls_for_each_from(sk, node) { 3075 if (seq_sk_match(seq, sk)) { 3076 if (iter->end_sk < iter->max_sk) { 3077 sock_hold(sk); 3078 iter->batch[iter->end_sk++] = sk; 3079 } 3080 expected++; 3081 } 3082 } 3083 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket)); 3084 3085 return expected; 3086 } 3087 3088 static struct sock *bpf_iter_tcp_batch(struct seq_file *seq) 3089 { 3090 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 3091 struct bpf_tcp_iter_state *iter = seq->private; 3092 struct tcp_iter_state *st = &iter->state; 3093 unsigned int expected; 3094 bool resized = false; 3095 struct sock *sk; 3096 3097 /* The st->bucket is done. Directly advance to the next 3098 * bucket instead of having the tcp_seek_last_pos() to skip 3099 * one by one in the current bucket and eventually find out 3100 * it has to advance to the next bucket. 3101 */ 3102 if (iter->st_bucket_done) { 3103 st->offset = 0; 3104 st->bucket++; 3105 if (st->state == TCP_SEQ_STATE_LISTENING && 3106 st->bucket > hinfo->lhash2_mask) { 3107 st->state = TCP_SEQ_STATE_ESTABLISHED; 3108 st->bucket = 0; 3109 } 3110 } 3111 3112 again: 3113 /* Get a new batch */ 3114 iter->cur_sk = 0; 3115 iter->end_sk = 0; 3116 iter->st_bucket_done = false; 3117 3118 sk = tcp_seek_last_pos(seq); 3119 if (!sk) 3120 return NULL; /* Done */ 3121 3122 if (st->state == TCP_SEQ_STATE_LISTENING) 3123 expected = bpf_iter_tcp_listening_batch(seq, sk); 3124 else 3125 expected = bpf_iter_tcp_established_batch(seq, sk); 3126 3127 if (iter->end_sk == expected) { 3128 iter->st_bucket_done = true; 3129 return sk; 3130 } 3131 3132 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) { 3133 resized = true; 3134 goto again; 3135 } 3136 3137 return sk; 3138 } 3139 3140 static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos) 3141 { 3142 /* bpf iter does not support lseek, so it always 3143 * continue from where it was stop()-ped. 3144 */ 3145 if (*pos) 3146 return bpf_iter_tcp_batch(seq); 3147 3148 return SEQ_START_TOKEN; 3149 } 3150 3151 static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 3152 { 3153 struct bpf_tcp_iter_state *iter = seq->private; 3154 struct tcp_iter_state *st = &iter->state; 3155 struct sock *sk; 3156 3157 /* Whenever seq_next() is called, the iter->cur_sk is 3158 * done with seq_show(), so advance to the next sk in 3159 * the batch. 3160 */ 3161 if (iter->cur_sk < iter->end_sk) { 3162 /* Keeping st->num consistent in tcp_iter_state. 3163 * bpf_iter_tcp does not use st->num. 3164 * meta.seq_num is used instead. 3165 */ 3166 st->num++; 3167 /* Move st->offset to the next sk in the bucket such that 3168 * the future start() will resume at st->offset in 3169 * st->bucket. See tcp_seek_last_pos(). 3170 */ 3171 st->offset++; 3172 sock_gen_put(iter->batch[iter->cur_sk++]); 3173 } 3174 3175 if (iter->cur_sk < iter->end_sk) 3176 sk = iter->batch[iter->cur_sk]; 3177 else 3178 sk = bpf_iter_tcp_batch(seq); 3179 3180 ++*pos; 3181 /* Keeping st->last_pos consistent in tcp_iter_state. 3182 * bpf iter does not do lseek, so st->last_pos always equals to *pos. 3183 */ 3184 st->last_pos = *pos; 3185 return sk; 3186 } 3187 3188 static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v) 3189 { 3190 struct bpf_iter_meta meta; 3191 struct bpf_prog *prog; 3192 struct sock *sk = v; 3193 uid_t uid; 3194 int ret; 3195 3196 if (v == SEQ_START_TOKEN) 3197 return 0; 3198 3199 if (sk_fullsock(sk)) 3200 lock_sock(sk); 3201 3202 if (unlikely(sk_unhashed(sk))) { 3203 ret = SEQ_SKIP; 3204 goto unlock; 3205 } 3206 3207 if (sk->sk_state == TCP_TIME_WAIT) { 3208 uid = 0; 3209 } else if (sk->sk_state == TCP_NEW_SYN_RECV) { 3210 const struct request_sock *req = v; 3211 3212 uid = from_kuid_munged(seq_user_ns(seq), 3213 sock_i_uid(req->rsk_listener)); 3214 } else { 3215 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)); 3216 } 3217 3218 meta.seq = seq; 3219 prog = bpf_iter_get_info(&meta, false); 3220 ret = tcp_prog_seq_show(prog, &meta, v, uid); 3221 3222 unlock: 3223 if (sk_fullsock(sk)) 3224 release_sock(sk); 3225 return ret; 3226 3227 } 3228 3229 static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v) 3230 { 3231 struct bpf_tcp_iter_state *iter = seq->private; 3232 struct bpf_iter_meta meta; 3233 struct bpf_prog *prog; 3234 3235 if (!v) { 3236 meta.seq = seq; 3237 prog = bpf_iter_get_info(&meta, true); 3238 if (prog) 3239 (void)tcp_prog_seq_show(prog, &meta, v, 0); 3240 } 3241 3242 if (iter->cur_sk < iter->end_sk) { 3243 bpf_iter_tcp_put_batch(iter); 3244 iter->st_bucket_done = false; 3245 } 3246 } 3247 3248 static const struct seq_operations bpf_iter_tcp_seq_ops = { 3249 .show = bpf_iter_tcp_seq_show, 3250 .start = bpf_iter_tcp_seq_start, 3251 .next = bpf_iter_tcp_seq_next, 3252 .stop = bpf_iter_tcp_seq_stop, 3253 }; 3254 #endif 3255 static unsigned short seq_file_family(const struct seq_file *seq) 3256 { 3257 const struct tcp_seq_afinfo *afinfo; 3258 3259 #ifdef CONFIG_BPF_SYSCALL 3260 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */ 3261 if (seq->op == &bpf_iter_tcp_seq_ops) 3262 return AF_UNSPEC; 3263 #endif 3264 3265 /* Iterated from proc fs */ 3266 afinfo = pde_data(file_inode(seq->file)); 3267 return afinfo->family; 3268 } 3269 3270 static const struct seq_operations tcp4_seq_ops = { 3271 .show = tcp4_seq_show, 3272 .start = tcp_seq_start, 3273 .next = tcp_seq_next, 3274 .stop = tcp_seq_stop, 3275 }; 3276 3277 static struct tcp_seq_afinfo tcp4_seq_afinfo = { 3278 .family = AF_INET, 3279 }; 3280 3281 static int __net_init tcp4_proc_init_net(struct net *net) 3282 { 3283 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops, 3284 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo)) 3285 return -ENOMEM; 3286 return 0; 3287 } 3288 3289 static void __net_exit tcp4_proc_exit_net(struct net *net) 3290 { 3291 remove_proc_entry("tcp", net->proc_net); 3292 } 3293 3294 static struct pernet_operations tcp4_net_ops = { 3295 .init = tcp4_proc_init_net, 3296 .exit = tcp4_proc_exit_net, 3297 }; 3298 3299 int __init tcp4_proc_init(void) 3300 { 3301 return register_pernet_subsys(&tcp4_net_ops); 3302 } 3303 3304 void tcp4_proc_exit(void) 3305 { 3306 unregister_pernet_subsys(&tcp4_net_ops); 3307 } 3308 #endif /* CONFIG_PROC_FS */ 3309 3310 /* @wake is one when sk_stream_write_space() calls us. 3311 * This sends EPOLLOUT only if notsent_bytes is half the limit. 3312 * This mimics the strategy used in sock_def_write_space(). 3313 */ 3314 bool tcp_stream_memory_free(const struct sock *sk, int wake) 3315 { 3316 const struct tcp_sock *tp = tcp_sk(sk); 3317 u32 notsent_bytes = READ_ONCE(tp->write_seq) - 3318 READ_ONCE(tp->snd_nxt); 3319 3320 return (notsent_bytes << wake) < tcp_notsent_lowat(tp); 3321 } 3322 EXPORT_SYMBOL(tcp_stream_memory_free); 3323 3324 struct proto tcp_prot = { 3325 .name = "TCP", 3326 .owner = THIS_MODULE, 3327 .close = tcp_close, 3328 .pre_connect = tcp_v4_pre_connect, 3329 .connect = tcp_v4_connect, 3330 .disconnect = tcp_disconnect, 3331 .accept = inet_csk_accept, 3332 .ioctl = tcp_ioctl, 3333 .init = tcp_v4_init_sock, 3334 .destroy = tcp_v4_destroy_sock, 3335 .shutdown = tcp_shutdown, 3336 .setsockopt = tcp_setsockopt, 3337 .getsockopt = tcp_getsockopt, 3338 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt, 3339 .keepalive = tcp_set_keepalive, 3340 .recvmsg = tcp_recvmsg, 3341 .sendmsg = tcp_sendmsg, 3342 .splice_eof = tcp_splice_eof, 3343 .backlog_rcv = tcp_v4_do_rcv, 3344 .release_cb = tcp_release_cb, 3345 .hash = inet_hash, 3346 .unhash = inet_unhash, 3347 .get_port = inet_csk_get_port, 3348 .put_port = inet_put_port, 3349 #ifdef CONFIG_BPF_SYSCALL 3350 .psock_update_sk_prot = tcp_bpf_update_proto, 3351 #endif 3352 .enter_memory_pressure = tcp_enter_memory_pressure, 3353 .leave_memory_pressure = tcp_leave_memory_pressure, 3354 .stream_memory_free = tcp_stream_memory_free, 3355 .sockets_allocated = &tcp_sockets_allocated, 3356 .orphan_count = &tcp_orphan_count, 3357 3358 .memory_allocated = &tcp_memory_allocated, 3359 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc, 3360 3361 .memory_pressure = &tcp_memory_pressure, 3362 .sysctl_mem = sysctl_tcp_mem, 3363 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 3364 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), 3365 .max_header = MAX_TCP_HEADER, 3366 .obj_size = sizeof(struct tcp_sock), 3367 .slab_flags = SLAB_TYPESAFE_BY_RCU, 3368 .twsk_prot = &tcp_timewait_sock_ops, 3369 .rsk_prot = &tcp_request_sock_ops, 3370 .h.hashinfo = NULL, 3371 .no_autobind = true, 3372 .diag_destroy = tcp_abort, 3373 }; 3374 EXPORT_SYMBOL(tcp_prot); 3375 3376 static void __net_exit tcp_sk_exit(struct net *net) 3377 { 3378 if (net->ipv4.tcp_congestion_control) 3379 bpf_module_put(net->ipv4.tcp_congestion_control, 3380 net->ipv4.tcp_congestion_control->owner); 3381 } 3382 3383 static void __net_init tcp_set_hashinfo(struct net *net) 3384 { 3385 struct inet_hashinfo *hinfo; 3386 unsigned int ehash_entries; 3387 struct net *old_net; 3388 3389 if (net_eq(net, &init_net)) 3390 goto fallback; 3391 3392 old_net = current->nsproxy->net_ns; 3393 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries); 3394 if (!ehash_entries) 3395 goto fallback; 3396 3397 ehash_entries = roundup_pow_of_two(ehash_entries); 3398 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries); 3399 if (!hinfo) { 3400 pr_warn("Failed to allocate TCP ehash (entries: %u) " 3401 "for a netns, fallback to the global one\n", 3402 ehash_entries); 3403 fallback: 3404 hinfo = &tcp_hashinfo; 3405 ehash_entries = tcp_hashinfo.ehash_mask + 1; 3406 } 3407 3408 net->ipv4.tcp_death_row.hashinfo = hinfo; 3409 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2; 3410 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128); 3411 } 3412 3413 static int __net_init tcp_sk_init(struct net *net) 3414 { 3415 net->ipv4.sysctl_tcp_ecn = 2; 3416 net->ipv4.sysctl_tcp_ecn_fallback = 1; 3417 3418 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS; 3419 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS; 3420 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD; 3421 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL; 3422 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS; 3423 3424 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME; 3425 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES; 3426 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL; 3427 3428 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES; 3429 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES; 3430 net->ipv4.sysctl_tcp_syncookies = 1; 3431 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH; 3432 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1; 3433 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2; 3434 net->ipv4.sysctl_tcp_orphan_retries = 0; 3435 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT; 3436 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX; 3437 net->ipv4.sysctl_tcp_tw_reuse = 2; 3438 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1; 3439 3440 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1); 3441 tcp_set_hashinfo(net); 3442 3443 net->ipv4.sysctl_tcp_sack = 1; 3444 net->ipv4.sysctl_tcp_window_scaling = 1; 3445 net->ipv4.sysctl_tcp_timestamps = 1; 3446 net->ipv4.sysctl_tcp_early_retrans = 3; 3447 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION; 3448 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */ 3449 net->ipv4.sysctl_tcp_retrans_collapse = 1; 3450 net->ipv4.sysctl_tcp_max_reordering = 300; 3451 net->ipv4.sysctl_tcp_dsack = 1; 3452 net->ipv4.sysctl_tcp_app_win = 31; 3453 net->ipv4.sysctl_tcp_adv_win_scale = 1; 3454 net->ipv4.sysctl_tcp_frto = 2; 3455 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1; 3456 /* This limits the percentage of the congestion window which we 3457 * will allow a single TSO frame to consume. Building TSO frames 3458 * which are too large can cause TCP streams to be bursty. 3459 */ 3460 net->ipv4.sysctl_tcp_tso_win_divisor = 3; 3461 /* Default TSQ limit of 16 TSO segments */ 3462 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536; 3463 3464 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */ 3465 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX; 3466 3467 net->ipv4.sysctl_tcp_min_tso_segs = 2; 3468 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */ 3469 net->ipv4.sysctl_tcp_min_rtt_wlen = 300; 3470 net->ipv4.sysctl_tcp_autocorking = 1; 3471 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2; 3472 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200; 3473 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120; 3474 if (net != &init_net) { 3475 memcpy(net->ipv4.sysctl_tcp_rmem, 3476 init_net.ipv4.sysctl_tcp_rmem, 3477 sizeof(init_net.ipv4.sysctl_tcp_rmem)); 3478 memcpy(net->ipv4.sysctl_tcp_wmem, 3479 init_net.ipv4.sysctl_tcp_wmem, 3480 sizeof(init_net.ipv4.sysctl_tcp_wmem)); 3481 } 3482 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC; 3483 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC; 3484 net->ipv4.sysctl_tcp_comp_sack_nr = 44; 3485 net->ipv4.sysctl_tcp_backlog_ack_defer = 1; 3486 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE; 3487 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0; 3488 atomic_set(&net->ipv4.tfo_active_disable_times, 0); 3489 3490 /* Set default values for PLB */ 3491 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */ 3492 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3; 3493 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12; 3494 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60; 3495 /* Default congestion threshold for PLB to mark a round is 50% */ 3496 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2; 3497 3498 /* Reno is always built in */ 3499 if (!net_eq(net, &init_net) && 3500 bpf_try_module_get(init_net.ipv4.tcp_congestion_control, 3501 init_net.ipv4.tcp_congestion_control->owner)) 3502 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control; 3503 else 3504 net->ipv4.tcp_congestion_control = &tcp_reno; 3505 3506 net->ipv4.sysctl_tcp_syn_linear_timeouts = 4; 3507 net->ipv4.sysctl_tcp_shrink_window = 0; 3508 3509 net->ipv4.sysctl_tcp_pingpong_thresh = 1; 3510 net->ipv4.sysctl_tcp_rto_min_us = jiffies_to_usecs(TCP_RTO_MIN); 3511 3512 return 0; 3513 } 3514 3515 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list) 3516 { 3517 struct net *net; 3518 3519 /* make sure concurrent calls to tcp_sk_exit_batch from net_cleanup_work 3520 * and failed setup_net error unwinding path are serialized. 3521 * 3522 * tcp_twsk_purge() handles twsk in any dead netns, not just those in 3523 * net_exit_list, the thread that dismantles a particular twsk must 3524 * do so without other thread progressing to refcount_dec_and_test() of 3525 * tcp_death_row.tw_refcount. 3526 */ 3527 mutex_lock(&tcp_exit_batch_mutex); 3528 3529 tcp_twsk_purge(net_exit_list); 3530 3531 list_for_each_entry(net, net_exit_list, exit_list) { 3532 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo); 3533 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount)); 3534 tcp_fastopen_ctx_destroy(net); 3535 } 3536 3537 mutex_unlock(&tcp_exit_batch_mutex); 3538 } 3539 3540 static struct pernet_operations __net_initdata tcp_sk_ops = { 3541 .init = tcp_sk_init, 3542 .exit = tcp_sk_exit, 3543 .exit_batch = tcp_sk_exit_batch, 3544 }; 3545 3546 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 3547 DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta, 3548 struct sock_common *sk_common, uid_t uid) 3549 3550 #define INIT_BATCH_SZ 16 3551 3552 static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux) 3553 { 3554 struct bpf_tcp_iter_state *iter = priv_data; 3555 int err; 3556 3557 err = bpf_iter_init_seq_net(priv_data, aux); 3558 if (err) 3559 return err; 3560 3561 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ); 3562 if (err) { 3563 bpf_iter_fini_seq_net(priv_data); 3564 return err; 3565 } 3566 3567 return 0; 3568 } 3569 3570 static void bpf_iter_fini_tcp(void *priv_data) 3571 { 3572 struct bpf_tcp_iter_state *iter = priv_data; 3573 3574 bpf_iter_fini_seq_net(priv_data); 3575 kvfree(iter->batch); 3576 } 3577 3578 static const struct bpf_iter_seq_info tcp_seq_info = { 3579 .seq_ops = &bpf_iter_tcp_seq_ops, 3580 .init_seq_private = bpf_iter_init_tcp, 3581 .fini_seq_private = bpf_iter_fini_tcp, 3582 .seq_priv_size = sizeof(struct bpf_tcp_iter_state), 3583 }; 3584 3585 static const struct bpf_func_proto * 3586 bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id, 3587 const struct bpf_prog *prog) 3588 { 3589 switch (func_id) { 3590 case BPF_FUNC_setsockopt: 3591 return &bpf_sk_setsockopt_proto; 3592 case BPF_FUNC_getsockopt: 3593 return &bpf_sk_getsockopt_proto; 3594 default: 3595 return NULL; 3596 } 3597 } 3598 3599 static struct bpf_iter_reg tcp_reg_info = { 3600 .target = "tcp", 3601 .ctx_arg_info_size = 1, 3602 .ctx_arg_info = { 3603 { offsetof(struct bpf_iter__tcp, sk_common), 3604 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED }, 3605 }, 3606 .get_func_proto = bpf_iter_tcp_get_func_proto, 3607 .seq_info = &tcp_seq_info, 3608 }; 3609 3610 static void __init bpf_iter_register(void) 3611 { 3612 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON]; 3613 if (bpf_iter_reg_target(&tcp_reg_info)) 3614 pr_warn("Warning: could not register bpf iterator tcp\n"); 3615 } 3616 3617 #endif 3618 3619 void __init tcp_v4_init(void) 3620 { 3621 int cpu, res; 3622 3623 for_each_possible_cpu(cpu) { 3624 struct sock *sk; 3625 3626 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW, 3627 IPPROTO_TCP, &init_net); 3628 if (res) 3629 panic("Failed to create the TCP control socket.\n"); 3630 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 3631 3632 /* Please enforce IP_DF and IPID==0 for RST and 3633 * ACK sent in SYN-RECV and TIME-WAIT state. 3634 */ 3635 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO; 3636 3637 sk->sk_clockid = CLOCK_MONOTONIC; 3638 3639 per_cpu(ipv4_tcp_sk.sock, cpu) = sk; 3640 } 3641 if (register_pernet_subsys(&tcp_sk_ops)) 3642 panic("Failed to create the TCP control socket.\n"); 3643 3644 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 3645 bpf_iter_register(); 3646 #endif 3647 } 3648