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 74 #include <linux/inet.h> 75 #include <linux/ipv6.h> 76 #include <linux/stddef.h> 77 #include <linux/proc_fs.h> 78 #include <linux/seq_file.h> 79 #include <linux/inetdevice.h> 80 #include <linux/btf_ids.h> 81 82 #include <crypto/hash.h> 83 #include <linux/scatterlist.h> 84 85 #include <trace/events/tcp.h> 86 87 #ifdef CONFIG_TCP_MD5SIG 88 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 89 __be32 daddr, __be32 saddr, const struct tcphdr *th); 90 #endif 91 92 struct inet_hashinfo tcp_hashinfo; 93 EXPORT_SYMBOL(tcp_hashinfo); 94 95 static DEFINE_PER_CPU(struct sock *, ipv4_tcp_sk); 96 97 static u32 tcp_v4_init_seq(const struct sk_buff *skb) 98 { 99 return secure_tcp_seq(ip_hdr(skb)->daddr, 100 ip_hdr(skb)->saddr, 101 tcp_hdr(skb)->dest, 102 tcp_hdr(skb)->source); 103 } 104 105 static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb) 106 { 107 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr); 108 } 109 110 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) 111 { 112 int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse); 113 const struct inet_timewait_sock *tw = inet_twsk(sktw); 114 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw); 115 struct tcp_sock *tp = tcp_sk(sk); 116 117 if (reuse == 2) { 118 /* Still does not detect *everything* that goes through 119 * lo, since we require a loopback src or dst address 120 * or direct binding to 'lo' interface. 121 */ 122 bool loopback = false; 123 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX) 124 loopback = true; 125 #if IS_ENABLED(CONFIG_IPV6) 126 if (tw->tw_family == AF_INET6) { 127 if (ipv6_addr_loopback(&tw->tw_v6_daddr) || 128 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) || 129 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) || 130 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr)) 131 loopback = true; 132 } else 133 #endif 134 { 135 if (ipv4_is_loopback(tw->tw_daddr) || 136 ipv4_is_loopback(tw->tw_rcv_saddr)) 137 loopback = true; 138 } 139 if (!loopback) 140 reuse = 0; 141 } 142 143 /* With PAWS, it is safe from the viewpoint 144 of data integrity. Even without PAWS it is safe provided sequence 145 spaces do not overlap i.e. at data rates <= 80Mbit/sec. 146 147 Actually, the idea is close to VJ's one, only timestamp cache is 148 held not per host, but per port pair and TW bucket is used as state 149 holder. 150 151 If TW bucket has been already destroyed we fall back to VJ's scheme 152 and use initial timestamp retrieved from peer table. 153 */ 154 if (tcptw->tw_ts_recent_stamp && 155 (!twp || (reuse && time_after32(ktime_get_seconds(), 156 tcptw->tw_ts_recent_stamp)))) { 157 /* In case of repair and re-using TIME-WAIT sockets we still 158 * want to be sure that it is safe as above but honor the 159 * sequence numbers and time stamps set as part of the repair 160 * process. 161 * 162 * Without this check re-using a TIME-WAIT socket with TCP 163 * repair would accumulate a -1 on the repair assigned 164 * sequence number. The first time it is reused the sequence 165 * is -1, the second time -2, etc. This fixes that issue 166 * without appearing to create any others. 167 */ 168 if (likely(!tp->repair)) { 169 u32 seq = tcptw->tw_snd_nxt + 65535 + 2; 170 171 if (!seq) 172 seq = 1; 173 WRITE_ONCE(tp->write_seq, seq); 174 tp->rx_opt.ts_recent = tcptw->tw_ts_recent; 175 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp; 176 } 177 sock_hold(sktw); 178 return 1; 179 } 180 181 return 0; 182 } 183 EXPORT_SYMBOL_GPL(tcp_twsk_unique); 184 185 static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr, 186 int addr_len) 187 { 188 /* This check is replicated from tcp_v4_connect() and intended to 189 * prevent BPF program called below from accessing bytes that are out 190 * of the bound specified by user in addr_len. 191 */ 192 if (addr_len < sizeof(struct sockaddr_in)) 193 return -EINVAL; 194 195 sock_owned_by_me(sk); 196 197 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr, &addr_len); 198 } 199 200 /* This will initiate an outgoing connection. */ 201 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 202 { 203 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; 204 struct inet_timewait_death_row *tcp_death_row; 205 struct inet_sock *inet = inet_sk(sk); 206 struct tcp_sock *tp = tcp_sk(sk); 207 struct ip_options_rcu *inet_opt; 208 struct net *net = sock_net(sk); 209 __be16 orig_sport, orig_dport; 210 __be32 daddr, nexthop; 211 struct flowi4 *fl4; 212 struct rtable *rt; 213 int err; 214 215 if (addr_len < sizeof(struct sockaddr_in)) 216 return -EINVAL; 217 218 if (usin->sin_family != AF_INET) 219 return -EAFNOSUPPORT; 220 221 nexthop = daddr = usin->sin_addr.s_addr; 222 inet_opt = rcu_dereference_protected(inet->inet_opt, 223 lockdep_sock_is_held(sk)); 224 if (inet_opt && inet_opt->opt.srr) { 225 if (!daddr) 226 return -EINVAL; 227 nexthop = inet_opt->opt.faddr; 228 } 229 230 orig_sport = inet->inet_sport; 231 orig_dport = usin->sin_port; 232 fl4 = &inet->cork.fl.u.ip4; 233 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr, 234 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport, 235 orig_dport, sk); 236 if (IS_ERR(rt)) { 237 err = PTR_ERR(rt); 238 if (err == -ENETUNREACH) 239 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); 240 return err; 241 } 242 243 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { 244 ip_rt_put(rt); 245 return -ENETUNREACH; 246 } 247 248 if (!inet_opt || !inet_opt->opt.srr) 249 daddr = fl4->daddr; 250 251 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row; 252 253 if (!inet->inet_saddr) { 254 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET); 255 if (err) { 256 ip_rt_put(rt); 257 return err; 258 } 259 } else { 260 sk_rcv_saddr_set(sk, inet->inet_saddr); 261 } 262 263 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) { 264 /* Reset inherited state */ 265 tp->rx_opt.ts_recent = 0; 266 tp->rx_opt.ts_recent_stamp = 0; 267 if (likely(!tp->repair)) 268 WRITE_ONCE(tp->write_seq, 0); 269 } 270 271 inet->inet_dport = usin->sin_port; 272 sk_daddr_set(sk, daddr); 273 274 inet_csk(sk)->icsk_ext_hdr_len = 0; 275 if (inet_opt) 276 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen; 277 278 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT; 279 280 /* Socket identity is still unknown (sport may be zero). 281 * However we set state to SYN-SENT and not releasing socket 282 * lock select source port, enter ourselves into the hash tables and 283 * complete initialization after this. 284 */ 285 tcp_set_state(sk, TCP_SYN_SENT); 286 err = inet_hash_connect(tcp_death_row, sk); 287 if (err) 288 goto failure; 289 290 sk_set_txhash(sk); 291 292 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport, 293 inet->inet_sport, inet->inet_dport, sk); 294 if (IS_ERR(rt)) { 295 err = PTR_ERR(rt); 296 rt = NULL; 297 goto failure; 298 } 299 tp->tcp_usec_ts = dst_tcp_usec_ts(&rt->dst); 300 /* OK, now commit destination to socket. */ 301 sk->sk_gso_type = SKB_GSO_TCPV4; 302 sk_setup_caps(sk, &rt->dst); 303 rt = NULL; 304 305 if (likely(!tp->repair)) { 306 if (!tp->write_seq) 307 WRITE_ONCE(tp->write_seq, 308 secure_tcp_seq(inet->inet_saddr, 309 inet->inet_daddr, 310 inet->inet_sport, 311 usin->sin_port)); 312 WRITE_ONCE(tp->tsoffset, 313 secure_tcp_ts_off(net, inet->inet_saddr, 314 inet->inet_daddr)); 315 } 316 317 atomic_set(&inet->inet_id, get_random_u16()); 318 319 if (tcp_fastopen_defer_connect(sk, &err)) 320 return err; 321 if (err) 322 goto failure; 323 324 err = tcp_connect(sk); 325 326 if (err) 327 goto failure; 328 329 return 0; 330 331 failure: 332 /* 333 * This unhashes the socket and releases the local port, 334 * if necessary. 335 */ 336 tcp_set_state(sk, TCP_CLOSE); 337 inet_bhash2_reset_saddr(sk); 338 ip_rt_put(rt); 339 sk->sk_route_caps = 0; 340 inet->inet_dport = 0; 341 return err; 342 } 343 EXPORT_SYMBOL(tcp_v4_connect); 344 345 /* 346 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191. 347 * It can be called through tcp_release_cb() if socket was owned by user 348 * at the time tcp_v4_err() was called to handle ICMP message. 349 */ 350 void tcp_v4_mtu_reduced(struct sock *sk) 351 { 352 struct inet_sock *inet = inet_sk(sk); 353 struct dst_entry *dst; 354 u32 mtu; 355 356 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) 357 return; 358 mtu = READ_ONCE(tcp_sk(sk)->mtu_info); 359 dst = inet_csk_update_pmtu(sk, mtu); 360 if (!dst) 361 return; 362 363 /* Something is about to be wrong... Remember soft error 364 * for the case, if this connection will not able to recover. 365 */ 366 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) 367 WRITE_ONCE(sk->sk_err_soft, EMSGSIZE); 368 369 mtu = dst_mtu(dst); 370 371 if (inet->pmtudisc != IP_PMTUDISC_DONT && 372 ip_sk_accept_pmtu(sk) && 373 inet_csk(sk)->icsk_pmtu_cookie > mtu) { 374 tcp_sync_mss(sk, mtu); 375 376 /* Resend the TCP packet because it's 377 * clear that the old packet has been 378 * dropped. This is the new "fast" path mtu 379 * discovery. 380 */ 381 tcp_simple_retransmit(sk); 382 } /* else let the usual retransmit timer handle it */ 383 } 384 EXPORT_SYMBOL(tcp_v4_mtu_reduced); 385 386 static void do_redirect(struct sk_buff *skb, struct sock *sk) 387 { 388 struct dst_entry *dst = __sk_dst_check(sk, 0); 389 390 if (dst) 391 dst->ops->redirect(dst, sk, skb); 392 } 393 394 395 /* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */ 396 void tcp_req_err(struct sock *sk, u32 seq, bool abort) 397 { 398 struct request_sock *req = inet_reqsk(sk); 399 struct net *net = sock_net(sk); 400 401 /* ICMPs are not backlogged, hence we cannot get 402 * an established socket here. 403 */ 404 if (seq != tcp_rsk(req)->snt_isn) { 405 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 406 } else if (abort) { 407 /* 408 * Still in SYN_RECV, just remove it silently. 409 * There is no good way to pass the error to the newly 410 * created socket, and POSIX does not want network 411 * errors returned from accept(). 412 */ 413 inet_csk_reqsk_queue_drop(req->rsk_listener, req); 414 tcp_listendrop(req->rsk_listener); 415 } 416 reqsk_put(req); 417 } 418 EXPORT_SYMBOL(tcp_req_err); 419 420 /* TCP-LD (RFC 6069) logic */ 421 void tcp_ld_RTO_revert(struct sock *sk, u32 seq) 422 { 423 struct inet_connection_sock *icsk = inet_csk(sk); 424 struct tcp_sock *tp = tcp_sk(sk); 425 struct sk_buff *skb; 426 s32 remaining; 427 u32 delta_us; 428 429 if (sock_owned_by_user(sk)) 430 return; 431 432 if (seq != tp->snd_una || !icsk->icsk_retransmits || 433 !icsk->icsk_backoff) 434 return; 435 436 skb = tcp_rtx_queue_head(sk); 437 if (WARN_ON_ONCE(!skb)) 438 return; 439 440 icsk->icsk_backoff--; 441 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT; 442 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX); 443 444 tcp_mstamp_refresh(tp); 445 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb)); 446 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us); 447 448 if (remaining > 0) { 449 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 450 remaining, TCP_RTO_MAX); 451 } else { 452 /* RTO revert clocked out retransmission. 453 * Will retransmit now. 454 */ 455 tcp_retransmit_timer(sk); 456 } 457 } 458 EXPORT_SYMBOL(tcp_ld_RTO_revert); 459 460 /* 461 * This routine is called by the ICMP module when it gets some 462 * sort of error condition. If err < 0 then the socket should 463 * be closed and the error returned to the user. If err > 0 464 * it's just the icmp type << 8 | icmp code. After adjustment 465 * header points to the first 8 bytes of the tcp header. We need 466 * to find the appropriate port. 467 * 468 * The locking strategy used here is very "optimistic". When 469 * someone else accesses the socket the ICMP is just dropped 470 * and for some paths there is no check at all. 471 * A more general error queue to queue errors for later handling 472 * is probably better. 473 * 474 */ 475 476 int tcp_v4_err(struct sk_buff *skb, u32 info) 477 { 478 const struct iphdr *iph = (const struct iphdr *)skb->data; 479 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2)); 480 struct tcp_sock *tp; 481 const int type = icmp_hdr(skb)->type; 482 const int code = icmp_hdr(skb)->code; 483 struct sock *sk; 484 struct request_sock *fastopen; 485 u32 seq, snd_una; 486 int err; 487 struct net *net = dev_net(skb->dev); 488 489 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, 490 iph->daddr, th->dest, iph->saddr, 491 ntohs(th->source), inet_iif(skb), 0); 492 if (!sk) { 493 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS); 494 return -ENOENT; 495 } 496 if (sk->sk_state == TCP_TIME_WAIT) { 497 /* To increase the counter of ignored icmps for TCP-AO */ 498 tcp_ao_ignore_icmp(sk, AF_INET, type, code); 499 inet_twsk_put(inet_twsk(sk)); 500 return 0; 501 } 502 seq = ntohl(th->seq); 503 if (sk->sk_state == TCP_NEW_SYN_RECV) { 504 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB || 505 type == ICMP_TIME_EXCEEDED || 506 (type == ICMP_DEST_UNREACH && 507 (code == ICMP_NET_UNREACH || 508 code == ICMP_HOST_UNREACH))); 509 return 0; 510 } 511 512 if (tcp_ao_ignore_icmp(sk, AF_INET, type, code)) { 513 sock_put(sk); 514 return 0; 515 } 516 517 bh_lock_sock(sk); 518 /* If too many ICMPs get dropped on busy 519 * servers this needs to be solved differently. 520 * We do take care of PMTU discovery (RFC1191) special case : 521 * we can receive locally generated ICMP messages while socket is held. 522 */ 523 if (sock_owned_by_user(sk)) { 524 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)) 525 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); 526 } 527 if (sk->sk_state == TCP_CLOSE) 528 goto out; 529 530 if (static_branch_unlikely(&ip4_min_ttl)) { 531 /* min_ttl can be changed concurrently from do_ip_setsockopt() */ 532 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) { 533 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); 534 goto out; 535 } 536 } 537 538 tp = tcp_sk(sk); 539 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */ 540 fastopen = rcu_dereference(tp->fastopen_rsk); 541 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una; 542 if (sk->sk_state != TCP_LISTEN && 543 !between(seq, snd_una, tp->snd_nxt)) { 544 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 545 goto out; 546 } 547 548 switch (type) { 549 case ICMP_REDIRECT: 550 if (!sock_owned_by_user(sk)) 551 do_redirect(skb, sk); 552 goto out; 553 case ICMP_SOURCE_QUENCH: 554 /* Just silently ignore these. */ 555 goto out; 556 case ICMP_PARAMETERPROB: 557 err = EPROTO; 558 break; 559 case ICMP_DEST_UNREACH: 560 if (code > NR_ICMP_UNREACH) 561 goto out; 562 563 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ 564 /* We are not interested in TCP_LISTEN and open_requests 565 * (SYN-ACKs send out by Linux are always <576bytes so 566 * they should go through unfragmented). 567 */ 568 if (sk->sk_state == TCP_LISTEN) 569 goto out; 570 571 WRITE_ONCE(tp->mtu_info, info); 572 if (!sock_owned_by_user(sk)) { 573 tcp_v4_mtu_reduced(sk); 574 } else { 575 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags)) 576 sock_hold(sk); 577 } 578 goto out; 579 } 580 581 err = icmp_err_convert[code].errno; 582 /* check if this ICMP message allows revert of backoff. 583 * (see RFC 6069) 584 */ 585 if (!fastopen && 586 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH)) 587 tcp_ld_RTO_revert(sk, seq); 588 break; 589 case ICMP_TIME_EXCEEDED: 590 err = EHOSTUNREACH; 591 break; 592 default: 593 goto out; 594 } 595 596 switch (sk->sk_state) { 597 case TCP_SYN_SENT: 598 case TCP_SYN_RECV: 599 /* Only in fast or simultaneous open. If a fast open socket is 600 * already accepted it is treated as a connected one below. 601 */ 602 if (fastopen && !fastopen->sk) 603 break; 604 605 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th); 606 607 if (!sock_owned_by_user(sk)) { 608 WRITE_ONCE(sk->sk_err, err); 609 610 sk_error_report(sk); 611 612 tcp_done(sk); 613 } else { 614 WRITE_ONCE(sk->sk_err_soft, err); 615 } 616 goto out; 617 } 618 619 /* If we've already connected we will keep trying 620 * until we time out, or the user gives up. 621 * 622 * rfc1122 4.2.3.9 allows to consider as hard errors 623 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, 624 * but it is obsoleted by pmtu discovery). 625 * 626 * Note, that in modern internet, where routing is unreliable 627 * and in each dark corner broken firewalls sit, sending random 628 * errors ordered by their masters even this two messages finally lose 629 * their original sense (even Linux sends invalid PORT_UNREACHs) 630 * 631 * Now we are in compliance with RFCs. 632 * --ANK (980905) 633 */ 634 635 if (!sock_owned_by_user(sk) && 636 inet_test_bit(RECVERR, sk)) { 637 WRITE_ONCE(sk->sk_err, err); 638 sk_error_report(sk); 639 } else { /* Only an error on timeout */ 640 WRITE_ONCE(sk->sk_err_soft, err); 641 } 642 643 out: 644 bh_unlock_sock(sk); 645 sock_put(sk); 646 return 0; 647 } 648 649 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr) 650 { 651 struct tcphdr *th = tcp_hdr(skb); 652 653 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0); 654 skb->csum_start = skb_transport_header(skb) - skb->head; 655 skb->csum_offset = offsetof(struct tcphdr, check); 656 } 657 658 /* This routine computes an IPv4 TCP checksum. */ 659 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) 660 { 661 const struct inet_sock *inet = inet_sk(sk); 662 663 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr); 664 } 665 EXPORT_SYMBOL(tcp_v4_send_check); 666 667 #define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32)) 668 669 static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb, 670 const struct tcp_ao_hdr *aoh, 671 struct ip_reply_arg *arg, struct tcphdr *reply, 672 __be32 reply_options[REPLY_OPTIONS_LEN]) 673 { 674 #ifdef CONFIG_TCP_AO 675 int sdif = tcp_v4_sdif(skb); 676 int dif = inet_iif(skb); 677 int l3index = sdif ? dif : 0; 678 bool allocated_traffic_key; 679 struct tcp_ao_key *key; 680 char *traffic_key; 681 bool drop = true; 682 u32 ao_sne = 0; 683 u8 keyid; 684 685 rcu_read_lock(); 686 if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, ntohl(reply->seq), 687 &key, &traffic_key, &allocated_traffic_key, 688 &keyid, &ao_sne)) 689 goto out; 690 691 reply_options[0] = htonl((TCPOPT_AO << 24) | (tcp_ao_len(key) << 16) | 692 (aoh->rnext_keyid << 8) | keyid); 693 arg->iov[0].iov_len += tcp_ao_len_aligned(key); 694 reply->doff = arg->iov[0].iov_len / 4; 695 696 if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1], 697 key, traffic_key, 698 (union tcp_ao_addr *)&ip_hdr(skb)->saddr, 699 (union tcp_ao_addr *)&ip_hdr(skb)->daddr, 700 reply, ao_sne)) 701 goto out; 702 drop = false; 703 out: 704 rcu_read_unlock(); 705 if (allocated_traffic_key) 706 kfree(traffic_key); 707 return drop; 708 #else 709 return true; 710 #endif 711 } 712 713 /* 714 * This routine will send an RST to the other tcp. 715 * 716 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.) 717 * for reset. 718 * Answer: if a packet caused RST, it is not for a socket 719 * existing in our system, if it is matched to a socket, 720 * it is just duplicate segment or bug in other side's TCP. 721 * So that we build reply only basing on parameters 722 * arrived with segment. 723 * Exception: precedence violation. We do not implement it in any case. 724 */ 725 726 static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) 727 { 728 const struct tcphdr *th = tcp_hdr(skb); 729 struct { 730 struct tcphdr th; 731 __be32 opt[REPLY_OPTIONS_LEN]; 732 } rep; 733 const __u8 *md5_hash_location = NULL; 734 const struct tcp_ao_hdr *aoh; 735 struct ip_reply_arg arg; 736 #ifdef CONFIG_TCP_MD5SIG 737 struct tcp_md5sig_key *key = NULL; 738 unsigned char newhash[16]; 739 struct sock *sk1 = NULL; 740 int genhash; 741 #endif 742 u64 transmit_time = 0; 743 struct sock *ctl_sk; 744 struct net *net; 745 u32 txhash = 0; 746 747 /* Never send a reset in response to a reset. */ 748 if (th->rst) 749 return; 750 751 /* If sk not NULL, it means we did a successful lookup and incoming 752 * route had to be correct. prequeue might have dropped our dst. 753 */ 754 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL) 755 return; 756 757 /* Swap the send and the receive. */ 758 memset(&rep, 0, sizeof(rep)); 759 rep.th.dest = th->source; 760 rep.th.source = th->dest; 761 rep.th.doff = sizeof(struct tcphdr) / 4; 762 rep.th.rst = 1; 763 764 if (th->ack) { 765 rep.th.seq = th->ack_seq; 766 } else { 767 rep.th.ack = 1; 768 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin + 769 skb->len - (th->doff << 2)); 770 } 771 772 memset(&arg, 0, sizeof(arg)); 773 arg.iov[0].iov_base = (unsigned char *)&rep; 774 arg.iov[0].iov_len = sizeof(rep.th); 775 776 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); 777 778 /* Invalid TCP option size or twice included auth */ 779 if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh)) 780 return; 781 782 if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt)) 783 return; 784 785 #ifdef CONFIG_TCP_MD5SIG 786 rcu_read_lock(); 787 if (sk && sk_fullsock(sk)) { 788 const union tcp_md5_addr *addr; 789 int l3index; 790 791 /* sdif set, means packet ingressed via a device 792 * in an L3 domain and inet_iif is set to it. 793 */ 794 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; 795 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 796 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 797 } else if (md5_hash_location) { 798 const union tcp_md5_addr *addr; 799 int sdif = tcp_v4_sdif(skb); 800 int dif = inet_iif(skb); 801 int l3index; 802 803 /* 804 * active side is lost. Try to find listening socket through 805 * source port, and then find md5 key through listening socket. 806 * we are not loose security here: 807 * Incoming packet is checked with md5 hash with finding key, 808 * no RST generated if md5 hash doesn't match. 809 */ 810 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo, 811 NULL, 0, ip_hdr(skb)->saddr, 812 th->source, ip_hdr(skb)->daddr, 813 ntohs(th->source), dif, sdif); 814 /* don't send rst if it can't find key */ 815 if (!sk1) 816 goto out; 817 818 /* sdif set, means packet ingressed via a device 819 * in an L3 domain and dif is set to it. 820 */ 821 l3index = sdif ? dif : 0; 822 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 823 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET); 824 if (!key) 825 goto out; 826 827 828 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb); 829 if (genhash || memcmp(md5_hash_location, newhash, 16) != 0) 830 goto out; 831 832 } 833 834 if (key) { 835 rep.opt[0] = htonl((TCPOPT_NOP << 24) | 836 (TCPOPT_NOP << 16) | 837 (TCPOPT_MD5SIG << 8) | 838 TCPOLEN_MD5SIG); 839 /* Update length and the length the header thinks exists */ 840 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 841 rep.th.doff = arg.iov[0].iov_len / 4; 842 843 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1], 844 key, ip_hdr(skb)->saddr, 845 ip_hdr(skb)->daddr, &rep.th); 846 } 847 #endif 848 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */ 849 if (rep.opt[0] == 0) { 850 __be32 mrst = mptcp_reset_option(skb); 851 852 if (mrst) { 853 rep.opt[0] = mrst; 854 arg.iov[0].iov_len += sizeof(mrst); 855 rep.th.doff = arg.iov[0].iov_len / 4; 856 } 857 } 858 859 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 860 ip_hdr(skb)->saddr, /* XXX */ 861 arg.iov[0].iov_len, IPPROTO_TCP, 0); 862 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 863 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0; 864 865 /* When socket is gone, all binding information is lost. 866 * routing might fail in this case. No choice here, if we choose to force 867 * input interface, we will misroute in case of asymmetric route. 868 */ 869 if (sk) 870 arg.bound_dev_if = sk->sk_bound_dev_if; 871 872 trace_tcp_send_reset(sk, skb); 873 874 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) != 875 offsetof(struct inet_timewait_sock, tw_bound_dev_if)); 876 877 arg.tos = ip_hdr(skb)->tos; 878 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL); 879 local_bh_disable(); 880 ctl_sk = this_cpu_read(ipv4_tcp_sk); 881 sock_net_set(ctl_sk, net); 882 if (sk) { 883 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ? 884 inet_twsk(sk)->tw_mark : sk->sk_mark; 885 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ? 886 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority); 887 transmit_time = tcp_transmit_time(sk); 888 xfrm_sk_clone_policy(ctl_sk, sk); 889 txhash = (sk->sk_state == TCP_TIME_WAIT) ? 890 inet_twsk(sk)->tw_txhash : sk->sk_txhash; 891 } else { 892 ctl_sk->sk_mark = 0; 893 ctl_sk->sk_priority = 0; 894 } 895 ip_send_unicast_reply(ctl_sk, 896 skb, &TCP_SKB_CB(skb)->header.h4.opt, 897 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 898 &arg, arg.iov[0].iov_len, 899 transmit_time, txhash); 900 901 xfrm_sk_free_policy(ctl_sk); 902 sock_net_set(ctl_sk, &init_net); 903 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); 904 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS); 905 local_bh_enable(); 906 907 #ifdef CONFIG_TCP_MD5SIG 908 out: 909 rcu_read_unlock(); 910 #endif 911 } 912 913 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states 914 outside socket context is ugly, certainly. What can I do? 915 */ 916 917 static void tcp_v4_send_ack(const struct sock *sk, 918 struct sk_buff *skb, u32 seq, u32 ack, 919 u32 win, u32 tsval, u32 tsecr, int oif, 920 struct tcp_key *key, 921 int reply_flags, u8 tos, u32 txhash) 922 { 923 const struct tcphdr *th = tcp_hdr(skb); 924 struct { 925 struct tcphdr th; 926 __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)]; 927 } rep; 928 struct net *net = sock_net(sk); 929 struct ip_reply_arg arg; 930 struct sock *ctl_sk; 931 u64 transmit_time; 932 933 memset(&rep.th, 0, sizeof(struct tcphdr)); 934 memset(&arg, 0, sizeof(arg)); 935 936 arg.iov[0].iov_base = (unsigned char *)&rep; 937 arg.iov[0].iov_len = sizeof(rep.th); 938 if (tsecr) { 939 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 940 (TCPOPT_TIMESTAMP << 8) | 941 TCPOLEN_TIMESTAMP); 942 rep.opt[1] = htonl(tsval); 943 rep.opt[2] = htonl(tsecr); 944 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED; 945 } 946 947 /* Swap the send and the receive. */ 948 rep.th.dest = th->source; 949 rep.th.source = th->dest; 950 rep.th.doff = arg.iov[0].iov_len / 4; 951 rep.th.seq = htonl(seq); 952 rep.th.ack_seq = htonl(ack); 953 rep.th.ack = 1; 954 rep.th.window = htons(win); 955 956 #ifdef CONFIG_TCP_MD5SIG 957 if (tcp_key_is_md5(key)) { 958 int offset = (tsecr) ? 3 : 0; 959 960 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) | 961 (TCPOPT_NOP << 16) | 962 (TCPOPT_MD5SIG << 8) | 963 TCPOLEN_MD5SIG); 964 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 965 rep.th.doff = arg.iov[0].iov_len/4; 966 967 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset], 968 key->md5_key, ip_hdr(skb)->saddr, 969 ip_hdr(skb)->daddr, &rep.th); 970 } 971 #endif 972 #ifdef CONFIG_TCP_AO 973 if (tcp_key_is_ao(key)) { 974 int offset = (tsecr) ? 3 : 0; 975 976 rep.opt[offset++] = htonl((TCPOPT_AO << 24) | 977 (tcp_ao_len(key->ao_key) << 16) | 978 (key->ao_key->sndid << 8) | 979 key->rcv_next); 980 arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key); 981 rep.th.doff = arg.iov[0].iov_len / 4; 982 983 tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset], 984 key->ao_key, key->traffic_key, 985 (union tcp_ao_addr *)&ip_hdr(skb)->saddr, 986 (union tcp_ao_addr *)&ip_hdr(skb)->daddr, 987 &rep.th, key->sne); 988 } 989 #endif 990 arg.flags = reply_flags; 991 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 992 ip_hdr(skb)->saddr, /* XXX */ 993 arg.iov[0].iov_len, IPPROTO_TCP, 0); 994 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 995 if (oif) 996 arg.bound_dev_if = oif; 997 arg.tos = tos; 998 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL); 999 local_bh_disable(); 1000 ctl_sk = this_cpu_read(ipv4_tcp_sk); 1001 sock_net_set(ctl_sk, net); 1002 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ? 1003 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark); 1004 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ? 1005 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority); 1006 transmit_time = tcp_transmit_time(sk); 1007 ip_send_unicast_reply(ctl_sk, 1008 skb, &TCP_SKB_CB(skb)->header.h4.opt, 1009 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 1010 &arg, arg.iov[0].iov_len, 1011 transmit_time, txhash); 1012 1013 sock_net_set(ctl_sk, &init_net); 1014 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); 1015 local_bh_enable(); 1016 } 1017 1018 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) 1019 { 1020 struct inet_timewait_sock *tw = inet_twsk(sk); 1021 struct tcp_timewait_sock *tcptw = tcp_twsk(sk); 1022 struct tcp_key key = {}; 1023 #ifdef CONFIG_TCP_AO 1024 struct tcp_ao_info *ao_info; 1025 1026 if (static_branch_unlikely(&tcp_ao_needed.key)) { 1027 /* FIXME: the segment to-be-acked is not verified yet */ 1028 ao_info = rcu_dereference(tcptw->ao_info); 1029 if (ao_info) { 1030 const struct tcp_ao_hdr *aoh; 1031 1032 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) { 1033 inet_twsk_put(tw); 1034 return; 1035 } 1036 1037 if (aoh) 1038 key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1); 1039 } 1040 } 1041 if (key.ao_key) { 1042 struct tcp_ao_key *rnext_key; 1043 1044 key.traffic_key = snd_other_key(key.ao_key); 1045 key.sne = READ_ONCE(ao_info->snd_sne); 1046 rnext_key = READ_ONCE(ao_info->rnext_key); 1047 key.rcv_next = rnext_key->rcvid; 1048 key.type = TCP_KEY_AO; 1049 #else 1050 if (0) { 1051 #endif 1052 #ifdef CONFIG_TCP_MD5SIG 1053 } else if (static_branch_unlikely(&tcp_md5_needed.key)) { 1054 key.md5_key = tcp_twsk_md5_key(tcptw); 1055 if (key.md5_key) 1056 key.type = TCP_KEY_MD5; 1057 #endif 1058 } 1059 1060 tcp_v4_send_ack(sk, skb, 1061 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, 1062 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, 1063 tcp_tw_tsval(tcptw), 1064 tcptw->tw_ts_recent, 1065 tw->tw_bound_dev_if, &key, 1066 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0, 1067 tw->tw_tos, 1068 tw->tw_txhash); 1069 1070 inet_twsk_put(tw); 1071 } 1072 1073 static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, 1074 struct request_sock *req) 1075 { 1076 struct tcp_key key = {}; 1077 1078 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV 1079 * sk->sk_state == TCP_SYN_RECV -> for Fast Open. 1080 */ 1081 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 : 1082 tcp_sk(sk)->snd_nxt; 1083 1084 #ifdef CONFIG_TCP_AO 1085 if (static_branch_unlikely(&tcp_ao_needed.key) && 1086 tcp_rsk_used_ao(req)) { 1087 const union tcp_md5_addr *addr; 1088 const struct tcp_ao_hdr *aoh; 1089 int l3index; 1090 1091 /* Invalid TCP option size or twice included auth */ 1092 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) 1093 return; 1094 if (!aoh) 1095 return; 1096 1097 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 1098 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; 1099 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, 1100 aoh->rnext_keyid, -1); 1101 if (unlikely(!key.ao_key)) { 1102 /* Send ACK with any matching MKT for the peer */ 1103 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1); 1104 /* Matching key disappeared (user removed the key?) 1105 * let the handshake timeout. 1106 */ 1107 if (!key.ao_key) { 1108 net_info_ratelimited("TCP-AO key for (%pI4, %d)->(%pI4, %d) suddenly disappeared, won't ACK new connection\n", 1109 addr, 1110 ntohs(tcp_hdr(skb)->source), 1111 &ip_hdr(skb)->daddr, 1112 ntohs(tcp_hdr(skb)->dest)); 1113 return; 1114 } 1115 } 1116 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC); 1117 if (!key.traffic_key) 1118 return; 1119 1120 key.type = TCP_KEY_AO; 1121 key.rcv_next = aoh->keyid; 1122 tcp_v4_ao_calc_key_rsk(key.ao_key, key.traffic_key, req); 1123 #else 1124 if (0) { 1125 #endif 1126 #ifdef CONFIG_TCP_MD5SIG 1127 } else if (static_branch_unlikely(&tcp_md5_needed.key)) { 1128 const union tcp_md5_addr *addr; 1129 int l3index; 1130 1131 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 1132 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; 1133 key.md5_key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 1134 if (key.md5_key) 1135 key.type = TCP_KEY_MD5; 1136 #endif 1137 } 1138 1139 /* RFC 7323 2.3 1140 * The window field (SEG.WND) of every outgoing segment, with the 1141 * exception of <SYN> segments, MUST be right-shifted by 1142 * Rcv.Wind.Shift bits: 1143 */ 1144 tcp_v4_send_ack(sk, skb, seq, 1145 tcp_rsk(req)->rcv_nxt, 1146 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale, 1147 tcp_rsk_tsval(tcp_rsk(req)), 1148 READ_ONCE(req->ts_recent), 1149 0, &key, 1150 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, 1151 ip_hdr(skb)->tos, 1152 READ_ONCE(tcp_rsk(req)->txhash)); 1153 if (tcp_key_is_ao(&key)) 1154 kfree(key.traffic_key); 1155 } 1156 1157 /* 1158 * Send a SYN-ACK after having received a SYN. 1159 * This still operates on a request_sock only, not on a big 1160 * socket. 1161 */ 1162 static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, 1163 struct flowi *fl, 1164 struct request_sock *req, 1165 struct tcp_fastopen_cookie *foc, 1166 enum tcp_synack_type synack_type, 1167 struct sk_buff *syn_skb) 1168 { 1169 const struct inet_request_sock *ireq = inet_rsk(req); 1170 struct flowi4 fl4; 1171 int err = -1; 1172 struct sk_buff *skb; 1173 u8 tos; 1174 1175 /* First, grab a route. */ 1176 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL) 1177 return -1; 1178 1179 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb); 1180 1181 if (skb) { 1182 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); 1183 1184 tos = READ_ONCE(inet_sk(sk)->tos); 1185 1186 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)) 1187 tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) | 1188 (tos & INET_ECN_MASK); 1189 1190 if (!INET_ECN_is_capable(tos) && 1191 tcp_bpf_ca_needs_ecn((struct sock *)req)) 1192 tos |= INET_ECN_ECT_0; 1193 1194 rcu_read_lock(); 1195 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, 1196 ireq->ir_rmt_addr, 1197 rcu_dereference(ireq->ireq_opt), 1198 tos); 1199 rcu_read_unlock(); 1200 err = net_xmit_eval(err); 1201 } 1202 1203 return err; 1204 } 1205 1206 /* 1207 * IPv4 request_sock destructor. 1208 */ 1209 static void tcp_v4_reqsk_destructor(struct request_sock *req) 1210 { 1211 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1)); 1212 } 1213 1214 #ifdef CONFIG_TCP_MD5SIG 1215 /* 1216 * RFC2385 MD5 checksumming requires a mapping of 1217 * IP address->MD5 Key. 1218 * We need to maintain these in the sk structure. 1219 */ 1220 1221 DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ); 1222 EXPORT_SYMBOL(tcp_md5_needed); 1223 1224 static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new) 1225 { 1226 if (!old) 1227 return true; 1228 1229 /* l3index always overrides non-l3index */ 1230 if (old->l3index && new->l3index == 0) 1231 return false; 1232 if (old->l3index == 0 && new->l3index) 1233 return true; 1234 1235 return old->prefixlen < new->prefixlen; 1236 } 1237 1238 /* Find the Key structure for an address. */ 1239 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1240 const union tcp_md5_addr *addr, 1241 int family, bool any_l3index) 1242 { 1243 const struct tcp_sock *tp = tcp_sk(sk); 1244 struct tcp_md5sig_key *key; 1245 const struct tcp_md5sig_info *md5sig; 1246 __be32 mask; 1247 struct tcp_md5sig_key *best_match = NULL; 1248 bool match; 1249 1250 /* caller either holds rcu_read_lock() or socket lock */ 1251 md5sig = rcu_dereference_check(tp->md5sig_info, 1252 lockdep_sock_is_held(sk)); 1253 if (!md5sig) 1254 return NULL; 1255 1256 hlist_for_each_entry_rcu(key, &md5sig->head, node, 1257 lockdep_sock_is_held(sk)) { 1258 if (key->family != family) 1259 continue; 1260 if (!any_l3index && key->flags & TCP_MD5SIG_FLAG_IFINDEX && 1261 key->l3index != l3index) 1262 continue; 1263 if (family == AF_INET) { 1264 mask = inet_make_mask(key->prefixlen); 1265 match = (key->addr.a4.s_addr & mask) == 1266 (addr->a4.s_addr & mask); 1267 #if IS_ENABLED(CONFIG_IPV6) 1268 } else if (family == AF_INET6) { 1269 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6, 1270 key->prefixlen); 1271 #endif 1272 } else { 1273 match = false; 1274 } 1275 1276 if (match && better_md5_match(best_match, key)) 1277 best_match = key; 1278 } 1279 return best_match; 1280 } 1281 EXPORT_SYMBOL(__tcp_md5_do_lookup); 1282 1283 static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk, 1284 const union tcp_md5_addr *addr, 1285 int family, u8 prefixlen, 1286 int l3index, u8 flags) 1287 { 1288 const struct tcp_sock *tp = tcp_sk(sk); 1289 struct tcp_md5sig_key *key; 1290 unsigned int size = sizeof(struct in_addr); 1291 const struct tcp_md5sig_info *md5sig; 1292 1293 /* caller either holds rcu_read_lock() or socket lock */ 1294 md5sig = rcu_dereference_check(tp->md5sig_info, 1295 lockdep_sock_is_held(sk)); 1296 if (!md5sig) 1297 return NULL; 1298 #if IS_ENABLED(CONFIG_IPV6) 1299 if (family == AF_INET6) 1300 size = sizeof(struct in6_addr); 1301 #endif 1302 hlist_for_each_entry_rcu(key, &md5sig->head, node, 1303 lockdep_sock_is_held(sk)) { 1304 if (key->family != family) 1305 continue; 1306 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX)) 1307 continue; 1308 if (key->l3index != l3index) 1309 continue; 1310 if (!memcmp(&key->addr, addr, size) && 1311 key->prefixlen == prefixlen) 1312 return key; 1313 } 1314 return NULL; 1315 } 1316 1317 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1318 const struct sock *addr_sk) 1319 { 1320 const union tcp_md5_addr *addr; 1321 int l3index; 1322 1323 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), 1324 addr_sk->sk_bound_dev_if); 1325 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr; 1326 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 1327 } 1328 EXPORT_SYMBOL(tcp_v4_md5_lookup); 1329 1330 static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp) 1331 { 1332 struct tcp_sock *tp = tcp_sk(sk); 1333 struct tcp_md5sig_info *md5sig; 1334 1335 md5sig = kmalloc(sizeof(*md5sig), gfp); 1336 if (!md5sig) 1337 return -ENOMEM; 1338 1339 sk_gso_disable(sk); 1340 INIT_HLIST_HEAD(&md5sig->head); 1341 rcu_assign_pointer(tp->md5sig_info, md5sig); 1342 return 0; 1343 } 1344 1345 /* This can be called on a newly created socket, from other files */ 1346 static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1347 int family, u8 prefixlen, int l3index, u8 flags, 1348 const u8 *newkey, u8 newkeylen, gfp_t gfp) 1349 { 1350 /* Add Key to the list */ 1351 struct tcp_md5sig_key *key; 1352 struct tcp_sock *tp = tcp_sk(sk); 1353 struct tcp_md5sig_info *md5sig; 1354 1355 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags); 1356 if (key) { 1357 /* Pre-existing entry - just update that one. 1358 * Note that the key might be used concurrently. 1359 * data_race() is telling kcsan that we do not care of 1360 * key mismatches, since changing MD5 key on live flows 1361 * can lead to packet drops. 1362 */ 1363 data_race(memcpy(key->key, newkey, newkeylen)); 1364 1365 /* Pairs with READ_ONCE() in tcp_md5_hash_key(). 1366 * Also note that a reader could catch new key->keylen value 1367 * but old key->key[], this is the reason we use __GFP_ZERO 1368 * at sock_kmalloc() time below these lines. 1369 */ 1370 WRITE_ONCE(key->keylen, newkeylen); 1371 1372 return 0; 1373 } 1374 1375 md5sig = rcu_dereference_protected(tp->md5sig_info, 1376 lockdep_sock_is_held(sk)); 1377 1378 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO); 1379 if (!key) 1380 return -ENOMEM; 1381 1382 memcpy(key->key, newkey, newkeylen); 1383 key->keylen = newkeylen; 1384 key->family = family; 1385 key->prefixlen = prefixlen; 1386 key->l3index = l3index; 1387 key->flags = flags; 1388 memcpy(&key->addr, addr, 1389 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) : 1390 sizeof(struct in_addr)); 1391 hlist_add_head_rcu(&key->node, &md5sig->head); 1392 return 0; 1393 } 1394 1395 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1396 int family, u8 prefixlen, int l3index, u8 flags, 1397 const u8 *newkey, u8 newkeylen) 1398 { 1399 struct tcp_sock *tp = tcp_sk(sk); 1400 1401 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) { 1402 if (tcp_md5_alloc_sigpool()) 1403 return -ENOMEM; 1404 1405 if (tcp_md5sig_info_add(sk, GFP_KERNEL)) { 1406 tcp_md5_release_sigpool(); 1407 return -ENOMEM; 1408 } 1409 1410 if (!static_branch_inc(&tcp_md5_needed.key)) { 1411 struct tcp_md5sig_info *md5sig; 1412 1413 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk)); 1414 rcu_assign_pointer(tp->md5sig_info, NULL); 1415 kfree_rcu(md5sig, rcu); 1416 tcp_md5_release_sigpool(); 1417 return -EUSERS; 1418 } 1419 } 1420 1421 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags, 1422 newkey, newkeylen, GFP_KERNEL); 1423 } 1424 EXPORT_SYMBOL(tcp_md5_do_add); 1425 1426 int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, 1427 int family, u8 prefixlen, int l3index, 1428 struct tcp_md5sig_key *key) 1429 { 1430 struct tcp_sock *tp = tcp_sk(sk); 1431 1432 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) { 1433 tcp_md5_add_sigpool(); 1434 1435 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) { 1436 tcp_md5_release_sigpool(); 1437 return -ENOMEM; 1438 } 1439 1440 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) { 1441 struct tcp_md5sig_info *md5sig; 1442 1443 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk)); 1444 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n"); 1445 rcu_assign_pointer(tp->md5sig_info, NULL); 1446 kfree_rcu(md5sig, rcu); 1447 tcp_md5_release_sigpool(); 1448 return -EUSERS; 1449 } 1450 } 1451 1452 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, 1453 key->flags, key->key, key->keylen, 1454 sk_gfp_mask(sk, GFP_ATOMIC)); 1455 } 1456 EXPORT_SYMBOL(tcp_md5_key_copy); 1457 1458 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family, 1459 u8 prefixlen, int l3index, u8 flags) 1460 { 1461 struct tcp_md5sig_key *key; 1462 1463 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags); 1464 if (!key) 1465 return -ENOENT; 1466 hlist_del_rcu(&key->node); 1467 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 1468 kfree_rcu(key, rcu); 1469 return 0; 1470 } 1471 EXPORT_SYMBOL(tcp_md5_do_del); 1472 1473 void tcp_clear_md5_list(struct sock *sk) 1474 { 1475 struct tcp_sock *tp = tcp_sk(sk); 1476 struct tcp_md5sig_key *key; 1477 struct hlist_node *n; 1478 struct tcp_md5sig_info *md5sig; 1479 1480 md5sig = rcu_dereference_protected(tp->md5sig_info, 1); 1481 1482 hlist_for_each_entry_safe(key, n, &md5sig->head, node) { 1483 hlist_del_rcu(&key->node); 1484 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 1485 kfree_rcu(key, rcu); 1486 } 1487 } 1488 1489 static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, 1490 sockptr_t optval, int optlen) 1491 { 1492 struct tcp_md5sig cmd; 1493 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr; 1494 const union tcp_md5_addr *addr; 1495 u8 prefixlen = 32; 1496 int l3index = 0; 1497 bool l3flag; 1498 u8 flags; 1499 1500 if (optlen < sizeof(cmd)) 1501 return -EINVAL; 1502 1503 if (copy_from_sockptr(&cmd, optval, sizeof(cmd))) 1504 return -EFAULT; 1505 1506 if (sin->sin_family != AF_INET) 1507 return -EINVAL; 1508 1509 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX; 1510 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX; 1511 1512 if (optname == TCP_MD5SIG_EXT && 1513 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) { 1514 prefixlen = cmd.tcpm_prefixlen; 1515 if (prefixlen > 32) 1516 return -EINVAL; 1517 } 1518 1519 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex && 1520 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) { 1521 struct net_device *dev; 1522 1523 rcu_read_lock(); 1524 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex); 1525 if (dev && netif_is_l3_master(dev)) 1526 l3index = dev->ifindex; 1527 1528 rcu_read_unlock(); 1529 1530 /* ok to reference set/not set outside of rcu; 1531 * right now device MUST be an L3 master 1532 */ 1533 if (!dev || !l3index) 1534 return -EINVAL; 1535 } 1536 1537 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr; 1538 1539 if (!cmd.tcpm_keylen) 1540 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags); 1541 1542 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) 1543 return -EINVAL; 1544 1545 /* Don't allow keys for peers that have a matching TCP-AO key. 1546 * See the comment in tcp_ao_add_cmd() 1547 */ 1548 if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false)) 1549 return -EKEYREJECTED; 1550 1551 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags, 1552 cmd.tcpm_key, cmd.tcpm_keylen); 1553 } 1554 1555 static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp, 1556 __be32 daddr, __be32 saddr, 1557 const struct tcphdr *th, int nbytes) 1558 { 1559 struct tcp4_pseudohdr *bp; 1560 struct scatterlist sg; 1561 struct tcphdr *_th; 1562 1563 bp = hp->scratch; 1564 bp->saddr = saddr; 1565 bp->daddr = daddr; 1566 bp->pad = 0; 1567 bp->protocol = IPPROTO_TCP; 1568 bp->len = cpu_to_be16(nbytes); 1569 1570 _th = (struct tcphdr *)(bp + 1); 1571 memcpy(_th, th, sizeof(*th)); 1572 _th->check = 0; 1573 1574 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th)); 1575 ahash_request_set_crypt(hp->req, &sg, NULL, 1576 sizeof(*bp) + sizeof(*th)); 1577 return crypto_ahash_update(hp->req); 1578 } 1579 1580 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 1581 __be32 daddr, __be32 saddr, const struct tcphdr *th) 1582 { 1583 struct tcp_sigpool hp; 1584 1585 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp)) 1586 goto clear_hash_nostart; 1587 1588 if (crypto_ahash_init(hp.req)) 1589 goto clear_hash; 1590 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2)) 1591 goto clear_hash; 1592 if (tcp_md5_hash_key(&hp, key)) 1593 goto clear_hash; 1594 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0); 1595 if (crypto_ahash_final(hp.req)) 1596 goto clear_hash; 1597 1598 tcp_sigpool_end(&hp); 1599 return 0; 1600 1601 clear_hash: 1602 tcp_sigpool_end(&hp); 1603 clear_hash_nostart: 1604 memset(md5_hash, 0, 16); 1605 return 1; 1606 } 1607 1608 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1609 const struct sock *sk, 1610 const struct sk_buff *skb) 1611 { 1612 const struct tcphdr *th = tcp_hdr(skb); 1613 struct tcp_sigpool hp; 1614 __be32 saddr, daddr; 1615 1616 if (sk) { /* valid for establish/request sockets */ 1617 saddr = sk->sk_rcv_saddr; 1618 daddr = sk->sk_daddr; 1619 } else { 1620 const struct iphdr *iph = ip_hdr(skb); 1621 saddr = iph->saddr; 1622 daddr = iph->daddr; 1623 } 1624 1625 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp)) 1626 goto clear_hash_nostart; 1627 1628 if (crypto_ahash_init(hp.req)) 1629 goto clear_hash; 1630 1631 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len)) 1632 goto clear_hash; 1633 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2)) 1634 goto clear_hash; 1635 if (tcp_md5_hash_key(&hp, key)) 1636 goto clear_hash; 1637 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0); 1638 if (crypto_ahash_final(hp.req)) 1639 goto clear_hash; 1640 1641 tcp_sigpool_end(&hp); 1642 return 0; 1643 1644 clear_hash: 1645 tcp_sigpool_end(&hp); 1646 clear_hash_nostart: 1647 memset(md5_hash, 0, 16); 1648 return 1; 1649 } 1650 EXPORT_SYMBOL(tcp_v4_md5_hash_skb); 1651 1652 #endif 1653 1654 static void tcp_v4_init_req(struct request_sock *req, 1655 const struct sock *sk_listener, 1656 struct sk_buff *skb) 1657 { 1658 struct inet_request_sock *ireq = inet_rsk(req); 1659 struct net *net = sock_net(sk_listener); 1660 1661 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr); 1662 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr); 1663 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb)); 1664 } 1665 1666 static struct dst_entry *tcp_v4_route_req(const struct sock *sk, 1667 struct sk_buff *skb, 1668 struct flowi *fl, 1669 struct request_sock *req) 1670 { 1671 tcp_v4_init_req(req, sk, skb); 1672 1673 if (security_inet_conn_request(sk, skb, req)) 1674 return NULL; 1675 1676 return inet_csk_route_req(sk, &fl->u.ip4, req); 1677 } 1678 1679 struct request_sock_ops tcp_request_sock_ops __read_mostly = { 1680 .family = PF_INET, 1681 .obj_size = sizeof(struct tcp_request_sock), 1682 .rtx_syn_ack = tcp_rtx_synack, 1683 .send_ack = tcp_v4_reqsk_send_ack, 1684 .destructor = tcp_v4_reqsk_destructor, 1685 .send_reset = tcp_v4_send_reset, 1686 .syn_ack_timeout = tcp_syn_ack_timeout, 1687 }; 1688 1689 const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { 1690 .mss_clamp = TCP_MSS_DEFAULT, 1691 #ifdef CONFIG_TCP_MD5SIG 1692 .req_md5_lookup = tcp_v4_md5_lookup, 1693 .calc_md5_hash = tcp_v4_md5_hash_skb, 1694 #endif 1695 #ifdef CONFIG_TCP_AO 1696 .ao_lookup = tcp_v4_ao_lookup_rsk, 1697 .ao_calc_key = tcp_v4_ao_calc_key_rsk, 1698 .ao_synack_hash = tcp_v4_ao_synack_hash, 1699 #endif 1700 #ifdef CONFIG_SYN_COOKIES 1701 .cookie_init_seq = cookie_v4_init_sequence, 1702 #endif 1703 .route_req = tcp_v4_route_req, 1704 .init_seq = tcp_v4_init_seq, 1705 .init_ts_off = tcp_v4_init_ts_off, 1706 .send_synack = tcp_v4_send_synack, 1707 }; 1708 1709 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) 1710 { 1711 /* Never answer to SYNs send to broadcast or multicast */ 1712 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) 1713 goto drop; 1714 1715 return tcp_conn_request(&tcp_request_sock_ops, 1716 &tcp_request_sock_ipv4_ops, sk, skb); 1717 1718 drop: 1719 tcp_listendrop(sk); 1720 return 0; 1721 } 1722 EXPORT_SYMBOL(tcp_v4_conn_request); 1723 1724 1725 /* 1726 * The three way handshake has completed - we got a valid synack - 1727 * now create the new socket. 1728 */ 1729 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 1730 struct request_sock *req, 1731 struct dst_entry *dst, 1732 struct request_sock *req_unhash, 1733 bool *own_req) 1734 { 1735 struct inet_request_sock *ireq; 1736 bool found_dup_sk = false; 1737 struct inet_sock *newinet; 1738 struct tcp_sock *newtp; 1739 struct sock *newsk; 1740 #ifdef CONFIG_TCP_MD5SIG 1741 const union tcp_md5_addr *addr; 1742 struct tcp_md5sig_key *key; 1743 int l3index; 1744 #endif 1745 struct ip_options_rcu *inet_opt; 1746 1747 if (sk_acceptq_is_full(sk)) 1748 goto exit_overflow; 1749 1750 newsk = tcp_create_openreq_child(sk, req, skb); 1751 if (!newsk) 1752 goto exit_nonewsk; 1753 1754 newsk->sk_gso_type = SKB_GSO_TCPV4; 1755 inet_sk_rx_dst_set(newsk, skb); 1756 1757 newtp = tcp_sk(newsk); 1758 newinet = inet_sk(newsk); 1759 ireq = inet_rsk(req); 1760 sk_daddr_set(newsk, ireq->ir_rmt_addr); 1761 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr); 1762 newsk->sk_bound_dev_if = ireq->ir_iif; 1763 newinet->inet_saddr = ireq->ir_loc_addr; 1764 inet_opt = rcu_dereference(ireq->ireq_opt); 1765 RCU_INIT_POINTER(newinet->inet_opt, inet_opt); 1766 newinet->mc_index = inet_iif(skb); 1767 newinet->mc_ttl = ip_hdr(skb)->ttl; 1768 newinet->rcv_tos = ip_hdr(skb)->tos; 1769 inet_csk(newsk)->icsk_ext_hdr_len = 0; 1770 if (inet_opt) 1771 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; 1772 atomic_set(&newinet->inet_id, get_random_u16()); 1773 1774 /* Set ToS of the new socket based upon the value of incoming SYN. 1775 * ECT bits are set later in tcp_init_transfer(). 1776 */ 1777 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)) 1778 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK; 1779 1780 if (!dst) { 1781 dst = inet_csk_route_child_sock(sk, newsk, req); 1782 if (!dst) 1783 goto put_and_exit; 1784 } else { 1785 /* syncookie case : see end of cookie_v4_check() */ 1786 } 1787 sk_setup_caps(newsk, dst); 1788 1789 tcp_ca_openreq_child(newsk, dst); 1790 1791 tcp_sync_mss(newsk, dst_mtu(dst)); 1792 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst)); 1793 1794 tcp_initialize_rcv_mss(newsk); 1795 1796 #ifdef CONFIG_TCP_MD5SIG 1797 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif); 1798 /* Copy over the MD5 key from the original socket */ 1799 addr = (union tcp_md5_addr *)&newinet->inet_daddr; 1800 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 1801 if (key && !tcp_rsk_used_ao(req)) { 1802 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key)) 1803 goto put_and_exit; 1804 sk_gso_disable(newsk); 1805 } 1806 #endif 1807 #ifdef CONFIG_TCP_AO 1808 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET)) 1809 goto put_and_exit; /* OOM, release back memory */ 1810 #endif 1811 1812 if (__inet_inherit_port(sk, newsk) < 0) 1813 goto put_and_exit; 1814 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), 1815 &found_dup_sk); 1816 if (likely(*own_req)) { 1817 tcp_move_syn(newtp, req); 1818 ireq->ireq_opt = NULL; 1819 } else { 1820 newinet->inet_opt = NULL; 1821 1822 if (!req_unhash && found_dup_sk) { 1823 /* This code path should only be executed in the 1824 * syncookie case only 1825 */ 1826 bh_unlock_sock(newsk); 1827 sock_put(newsk); 1828 newsk = NULL; 1829 } 1830 } 1831 return newsk; 1832 1833 exit_overflow: 1834 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 1835 exit_nonewsk: 1836 dst_release(dst); 1837 exit: 1838 tcp_listendrop(sk); 1839 return NULL; 1840 put_and_exit: 1841 newinet->inet_opt = NULL; 1842 inet_csk_prepare_forced_close(newsk); 1843 tcp_done(newsk); 1844 goto exit; 1845 } 1846 EXPORT_SYMBOL(tcp_v4_syn_recv_sock); 1847 1848 static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb) 1849 { 1850 #ifdef CONFIG_SYN_COOKIES 1851 const struct tcphdr *th = tcp_hdr(skb); 1852 1853 if (!th->syn) 1854 sk = cookie_v4_check(sk, skb); 1855 #endif 1856 return sk; 1857 } 1858 1859 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 1860 struct tcphdr *th, u32 *cookie) 1861 { 1862 u16 mss = 0; 1863 #ifdef CONFIG_SYN_COOKIES 1864 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops, 1865 &tcp_request_sock_ipv4_ops, sk, th); 1866 if (mss) { 1867 *cookie = __cookie_v4_init_sequence(iph, th, &mss); 1868 tcp_synq_overflow(sk); 1869 } 1870 #endif 1871 return mss; 1872 } 1873 1874 INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *, 1875 u32)); 1876 /* The socket must have it's spinlock held when we get 1877 * here, unless it is a TCP_LISTEN socket. 1878 * 1879 * We have a potential double-lock case here, so even when 1880 * doing backlog processing we use the BH locking scheme. 1881 * This is because we cannot sleep with the original spinlock 1882 * held. 1883 */ 1884 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) 1885 { 1886 enum skb_drop_reason reason; 1887 struct sock *rsk; 1888 1889 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ 1890 struct dst_entry *dst; 1891 1892 dst = rcu_dereference_protected(sk->sk_rx_dst, 1893 lockdep_sock_is_held(sk)); 1894 1895 sock_rps_save_rxhash(sk, skb); 1896 sk_mark_napi_id(sk, skb); 1897 if (dst) { 1898 if (sk->sk_rx_dst_ifindex != skb->skb_iif || 1899 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check, 1900 dst, 0)) { 1901 RCU_INIT_POINTER(sk->sk_rx_dst, NULL); 1902 dst_release(dst); 1903 } 1904 } 1905 tcp_rcv_established(sk, skb); 1906 return 0; 1907 } 1908 1909 if (tcp_checksum_complete(skb)) 1910 goto csum_err; 1911 1912 if (sk->sk_state == TCP_LISTEN) { 1913 struct sock *nsk = tcp_v4_cookie_check(sk, skb); 1914 1915 if (!nsk) 1916 return 0; 1917 if (nsk != sk) { 1918 reason = tcp_child_process(sk, nsk, skb); 1919 if (reason) { 1920 rsk = nsk; 1921 goto reset; 1922 } 1923 return 0; 1924 } 1925 } else 1926 sock_rps_save_rxhash(sk, skb); 1927 1928 reason = tcp_rcv_state_process(sk, skb); 1929 if (reason) { 1930 rsk = sk; 1931 goto reset; 1932 } 1933 return 0; 1934 1935 reset: 1936 tcp_v4_send_reset(rsk, skb); 1937 discard: 1938 kfree_skb_reason(skb, reason); 1939 /* Be careful here. If this function gets more complicated and 1940 * gcc suffers from register pressure on the x86, sk (in %ebx) 1941 * might be destroyed here. This current version compiles correctly, 1942 * but you have been warned. 1943 */ 1944 return 0; 1945 1946 csum_err: 1947 reason = SKB_DROP_REASON_TCP_CSUM; 1948 trace_tcp_bad_csum(skb); 1949 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); 1950 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); 1951 goto discard; 1952 } 1953 EXPORT_SYMBOL(tcp_v4_do_rcv); 1954 1955 int tcp_v4_early_demux(struct sk_buff *skb) 1956 { 1957 struct net *net = dev_net(skb->dev); 1958 const struct iphdr *iph; 1959 const struct tcphdr *th; 1960 struct sock *sk; 1961 1962 if (skb->pkt_type != PACKET_HOST) 1963 return 0; 1964 1965 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr))) 1966 return 0; 1967 1968 iph = ip_hdr(skb); 1969 th = tcp_hdr(skb); 1970 1971 if (th->doff < sizeof(struct tcphdr) / 4) 1972 return 0; 1973 1974 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, 1975 iph->saddr, th->source, 1976 iph->daddr, ntohs(th->dest), 1977 skb->skb_iif, inet_sdif(skb)); 1978 if (sk) { 1979 skb->sk = sk; 1980 skb->destructor = sock_edemux; 1981 if (sk_fullsock(sk)) { 1982 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst); 1983 1984 if (dst) 1985 dst = dst_check(dst, 0); 1986 if (dst && 1987 sk->sk_rx_dst_ifindex == skb->skb_iif) 1988 skb_dst_set_noref(skb, dst); 1989 } 1990 } 1991 return 0; 1992 } 1993 1994 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, 1995 enum skb_drop_reason *reason) 1996 { 1997 u32 limit, tail_gso_size, tail_gso_segs; 1998 struct skb_shared_info *shinfo; 1999 const struct tcphdr *th; 2000 struct tcphdr *thtail; 2001 struct sk_buff *tail; 2002 unsigned int hdrlen; 2003 bool fragstolen; 2004 u32 gso_segs; 2005 u32 gso_size; 2006 int delta; 2007 2008 /* In case all data was pulled from skb frags (in __pskb_pull_tail()), 2009 * we can fix skb->truesize to its real value to avoid future drops. 2010 * This is valid because skb is not yet charged to the socket. 2011 * It has been noticed pure SACK packets were sometimes dropped 2012 * (if cooked by drivers without copybreak feature). 2013 */ 2014 skb_condense(skb); 2015 2016 skb_dst_drop(skb); 2017 2018 if (unlikely(tcp_checksum_complete(skb))) { 2019 bh_unlock_sock(sk); 2020 trace_tcp_bad_csum(skb); 2021 *reason = SKB_DROP_REASON_TCP_CSUM; 2022 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); 2023 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); 2024 return true; 2025 } 2026 2027 /* Attempt coalescing to last skb in backlog, even if we are 2028 * above the limits. 2029 * This is okay because skb capacity is limited to MAX_SKB_FRAGS. 2030 */ 2031 th = (const struct tcphdr *)skb->data; 2032 hdrlen = th->doff * 4; 2033 2034 tail = sk->sk_backlog.tail; 2035 if (!tail) 2036 goto no_coalesce; 2037 thtail = (struct tcphdr *)tail->data; 2038 2039 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq || 2040 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield || 2041 ((TCP_SKB_CB(tail)->tcp_flags | 2042 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) || 2043 !((TCP_SKB_CB(tail)->tcp_flags & 2044 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) || 2045 ((TCP_SKB_CB(tail)->tcp_flags ^ 2046 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) || 2047 #ifdef CONFIG_TLS_DEVICE 2048 tail->decrypted != skb->decrypted || 2049 #endif 2050 !mptcp_skb_can_collapse(tail, skb) || 2051 thtail->doff != th->doff || 2052 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th))) 2053 goto no_coalesce; 2054 2055 __skb_pull(skb, hdrlen); 2056 2057 shinfo = skb_shinfo(skb); 2058 gso_size = shinfo->gso_size ?: skb->len; 2059 gso_segs = shinfo->gso_segs ?: 1; 2060 2061 shinfo = skb_shinfo(tail); 2062 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen); 2063 tail_gso_segs = shinfo->gso_segs ?: 1; 2064 2065 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) { 2066 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq; 2067 2068 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) { 2069 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq; 2070 thtail->window = th->window; 2071 } 2072 2073 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and 2074 * thtail->fin, so that the fast path in tcp_rcv_established() 2075 * is not entered if we append a packet with a FIN. 2076 * SYN, RST, URG are not present. 2077 * ACK is set on both packets. 2078 * PSH : we do not really care in TCP stack, 2079 * at least for 'GRO' packets. 2080 */ 2081 thtail->fin |= th->fin; 2082 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags; 2083 2084 if (TCP_SKB_CB(skb)->has_rxtstamp) { 2085 TCP_SKB_CB(tail)->has_rxtstamp = true; 2086 tail->tstamp = skb->tstamp; 2087 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp; 2088 } 2089 2090 /* Not as strict as GRO. We only need to carry mss max value */ 2091 shinfo->gso_size = max(gso_size, tail_gso_size); 2092 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF); 2093 2094 sk->sk_backlog.len += delta; 2095 __NET_INC_STATS(sock_net(sk), 2096 LINUX_MIB_TCPBACKLOGCOALESCE); 2097 kfree_skb_partial(skb, fragstolen); 2098 return false; 2099 } 2100 __skb_push(skb, hdrlen); 2101 2102 no_coalesce: 2103 limit = (u32)READ_ONCE(sk->sk_rcvbuf) + (u32)(READ_ONCE(sk->sk_sndbuf) >> 1); 2104 2105 /* Only socket owner can try to collapse/prune rx queues 2106 * to reduce memory overhead, so add a little headroom here. 2107 * Few sockets backlog are possibly concurrently non empty. 2108 */ 2109 limit += 64 * 1024; 2110 2111 if (unlikely(sk_add_backlog(sk, skb, limit))) { 2112 bh_unlock_sock(sk); 2113 *reason = SKB_DROP_REASON_SOCKET_BACKLOG; 2114 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP); 2115 return true; 2116 } 2117 return false; 2118 } 2119 EXPORT_SYMBOL(tcp_add_backlog); 2120 2121 int tcp_filter(struct sock *sk, struct sk_buff *skb) 2122 { 2123 struct tcphdr *th = (struct tcphdr *)skb->data; 2124 2125 return sk_filter_trim_cap(sk, skb, th->doff * 4); 2126 } 2127 EXPORT_SYMBOL(tcp_filter); 2128 2129 static void tcp_v4_restore_cb(struct sk_buff *skb) 2130 { 2131 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4, 2132 sizeof(struct inet_skb_parm)); 2133 } 2134 2135 static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph, 2136 const struct tcphdr *th) 2137 { 2138 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB() 2139 * barrier() makes sure compiler wont play fool^Waliasing games. 2140 */ 2141 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb), 2142 sizeof(struct inet_skb_parm)); 2143 barrier(); 2144 2145 TCP_SKB_CB(skb)->seq = ntohl(th->seq); 2146 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + 2147 skb->len - th->doff * 4); 2148 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); 2149 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th); 2150 TCP_SKB_CB(skb)->tcp_tw_isn = 0; 2151 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph); 2152 TCP_SKB_CB(skb)->sacked = 0; 2153 TCP_SKB_CB(skb)->has_rxtstamp = 2154 skb->tstamp || skb_hwtstamps(skb)->hwtstamp; 2155 } 2156 2157 /* 2158 * From tcp_input.c 2159 */ 2160 2161 int tcp_v4_rcv(struct sk_buff *skb) 2162 { 2163 struct net *net = dev_net(skb->dev); 2164 enum skb_drop_reason drop_reason; 2165 int sdif = inet_sdif(skb); 2166 int dif = inet_iif(skb); 2167 const struct iphdr *iph; 2168 const struct tcphdr *th; 2169 bool refcounted; 2170 struct sock *sk; 2171 int ret; 2172 2173 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; 2174 if (skb->pkt_type != PACKET_HOST) 2175 goto discard_it; 2176 2177 /* Count it even if it's bad */ 2178 __TCP_INC_STATS(net, TCP_MIB_INSEGS); 2179 2180 if (!pskb_may_pull(skb, sizeof(struct tcphdr))) 2181 goto discard_it; 2182 2183 th = (const struct tcphdr *)skb->data; 2184 2185 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) { 2186 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL; 2187 goto bad_packet; 2188 } 2189 if (!pskb_may_pull(skb, th->doff * 4)) 2190 goto discard_it; 2191 2192 /* An explanation is required here, I think. 2193 * Packet length and doff are validated by header prediction, 2194 * provided case of th->doff==0 is eliminated. 2195 * So, we defer the checks. */ 2196 2197 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo)) 2198 goto csum_error; 2199 2200 th = (const struct tcphdr *)skb->data; 2201 iph = ip_hdr(skb); 2202 lookup: 2203 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo, 2204 skb, __tcp_hdrlen(th), th->source, 2205 th->dest, sdif, &refcounted); 2206 if (!sk) 2207 goto no_tcp_socket; 2208 2209 process: 2210 if (sk->sk_state == TCP_TIME_WAIT) 2211 goto do_time_wait; 2212 2213 if (sk->sk_state == TCP_NEW_SYN_RECV) { 2214 struct request_sock *req = inet_reqsk(sk); 2215 bool req_stolen = false; 2216 struct sock *nsk; 2217 2218 sk = req->rsk_listener; 2219 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 2220 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 2221 else 2222 drop_reason = tcp_inbound_hash(sk, req, skb, 2223 &iph->saddr, &iph->daddr, 2224 AF_INET, dif, sdif); 2225 if (unlikely(drop_reason)) { 2226 sk_drops_add(sk, skb); 2227 reqsk_put(req); 2228 goto discard_it; 2229 } 2230 if (tcp_checksum_complete(skb)) { 2231 reqsk_put(req); 2232 goto csum_error; 2233 } 2234 if (unlikely(sk->sk_state != TCP_LISTEN)) { 2235 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb); 2236 if (!nsk) { 2237 inet_csk_reqsk_queue_drop_and_put(sk, req); 2238 goto lookup; 2239 } 2240 sk = nsk; 2241 /* reuseport_migrate_sock() has already held one sk_refcnt 2242 * before returning. 2243 */ 2244 } else { 2245 /* We own a reference on the listener, increase it again 2246 * as we might lose it too soon. 2247 */ 2248 sock_hold(sk); 2249 } 2250 refcounted = true; 2251 nsk = NULL; 2252 if (!tcp_filter(sk, skb)) { 2253 th = (const struct tcphdr *)skb->data; 2254 iph = ip_hdr(skb); 2255 tcp_v4_fill_cb(skb, iph, th); 2256 nsk = tcp_check_req(sk, skb, req, false, &req_stolen); 2257 } else { 2258 drop_reason = SKB_DROP_REASON_SOCKET_FILTER; 2259 } 2260 if (!nsk) { 2261 reqsk_put(req); 2262 if (req_stolen) { 2263 /* Another cpu got exclusive access to req 2264 * and created a full blown socket. 2265 * Try to feed this packet to this socket 2266 * instead of discarding it. 2267 */ 2268 tcp_v4_restore_cb(skb); 2269 sock_put(sk); 2270 goto lookup; 2271 } 2272 goto discard_and_relse; 2273 } 2274 nf_reset_ct(skb); 2275 if (nsk == sk) { 2276 reqsk_put(req); 2277 tcp_v4_restore_cb(skb); 2278 } else { 2279 drop_reason = tcp_child_process(sk, nsk, skb); 2280 if (drop_reason) { 2281 tcp_v4_send_reset(nsk, skb); 2282 goto discard_and_relse; 2283 } 2284 sock_put(sk); 2285 return 0; 2286 } 2287 } 2288 2289 if (static_branch_unlikely(&ip4_min_ttl)) { 2290 /* min_ttl can be changed concurrently from do_ip_setsockopt() */ 2291 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) { 2292 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); 2293 drop_reason = SKB_DROP_REASON_TCP_MINTTL; 2294 goto discard_and_relse; 2295 } 2296 } 2297 2298 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) { 2299 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 2300 goto discard_and_relse; 2301 } 2302 2303 drop_reason = tcp_inbound_hash(sk, NULL, skb, &iph->saddr, &iph->daddr, 2304 AF_INET, dif, sdif); 2305 if (drop_reason) 2306 goto discard_and_relse; 2307 2308 nf_reset_ct(skb); 2309 2310 if (tcp_filter(sk, skb)) { 2311 drop_reason = SKB_DROP_REASON_SOCKET_FILTER; 2312 goto discard_and_relse; 2313 } 2314 th = (const struct tcphdr *)skb->data; 2315 iph = ip_hdr(skb); 2316 tcp_v4_fill_cb(skb, iph, th); 2317 2318 skb->dev = NULL; 2319 2320 if (sk->sk_state == TCP_LISTEN) { 2321 ret = tcp_v4_do_rcv(sk, skb); 2322 goto put_and_return; 2323 } 2324 2325 sk_incoming_cpu_update(sk); 2326 2327 bh_lock_sock_nested(sk); 2328 tcp_segs_in(tcp_sk(sk), skb); 2329 ret = 0; 2330 if (!sock_owned_by_user(sk)) { 2331 ret = tcp_v4_do_rcv(sk, skb); 2332 } else { 2333 if (tcp_add_backlog(sk, skb, &drop_reason)) 2334 goto discard_and_relse; 2335 } 2336 bh_unlock_sock(sk); 2337 2338 put_and_return: 2339 if (refcounted) 2340 sock_put(sk); 2341 2342 return ret; 2343 2344 no_tcp_socket: 2345 drop_reason = SKB_DROP_REASON_NO_SOCKET; 2346 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 2347 goto discard_it; 2348 2349 tcp_v4_fill_cb(skb, iph, th); 2350 2351 if (tcp_checksum_complete(skb)) { 2352 csum_error: 2353 drop_reason = SKB_DROP_REASON_TCP_CSUM; 2354 trace_tcp_bad_csum(skb); 2355 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS); 2356 bad_packet: 2357 __TCP_INC_STATS(net, TCP_MIB_INERRS); 2358 } else { 2359 tcp_v4_send_reset(NULL, skb); 2360 } 2361 2362 discard_it: 2363 SKB_DR_OR(drop_reason, NOT_SPECIFIED); 2364 /* Discard frame. */ 2365 kfree_skb_reason(skb, drop_reason); 2366 return 0; 2367 2368 discard_and_relse: 2369 sk_drops_add(sk, skb); 2370 if (refcounted) 2371 sock_put(sk); 2372 goto discard_it; 2373 2374 do_time_wait: 2375 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 2376 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 2377 inet_twsk_put(inet_twsk(sk)); 2378 goto discard_it; 2379 } 2380 2381 tcp_v4_fill_cb(skb, iph, th); 2382 2383 if (tcp_checksum_complete(skb)) { 2384 inet_twsk_put(inet_twsk(sk)); 2385 goto csum_error; 2386 } 2387 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) { 2388 case TCP_TW_SYN: { 2389 struct sock *sk2 = inet_lookup_listener(net, 2390 net->ipv4.tcp_death_row.hashinfo, 2391 skb, __tcp_hdrlen(th), 2392 iph->saddr, th->source, 2393 iph->daddr, th->dest, 2394 inet_iif(skb), 2395 sdif); 2396 if (sk2) { 2397 inet_twsk_deschedule_put(inet_twsk(sk)); 2398 sk = sk2; 2399 tcp_v4_restore_cb(skb); 2400 refcounted = false; 2401 goto process; 2402 } 2403 } 2404 /* to ACK */ 2405 fallthrough; 2406 case TCP_TW_ACK: 2407 tcp_v4_timewait_ack(sk, skb); 2408 break; 2409 case TCP_TW_RST: 2410 tcp_v4_send_reset(sk, skb); 2411 inet_twsk_deschedule_put(inet_twsk(sk)); 2412 goto discard_it; 2413 case TCP_TW_SUCCESS:; 2414 } 2415 goto discard_it; 2416 } 2417 2418 static struct timewait_sock_ops tcp_timewait_sock_ops = { 2419 .twsk_obj_size = sizeof(struct tcp_timewait_sock), 2420 .twsk_unique = tcp_twsk_unique, 2421 .twsk_destructor= tcp_twsk_destructor, 2422 }; 2423 2424 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) 2425 { 2426 struct dst_entry *dst = skb_dst(skb); 2427 2428 if (dst && dst_hold_safe(dst)) { 2429 rcu_assign_pointer(sk->sk_rx_dst, dst); 2430 sk->sk_rx_dst_ifindex = skb->skb_iif; 2431 } 2432 } 2433 EXPORT_SYMBOL(inet_sk_rx_dst_set); 2434 2435 const struct inet_connection_sock_af_ops ipv4_specific = { 2436 .queue_xmit = ip_queue_xmit, 2437 .send_check = tcp_v4_send_check, 2438 .rebuild_header = inet_sk_rebuild_header, 2439 .sk_rx_dst_set = inet_sk_rx_dst_set, 2440 .conn_request = tcp_v4_conn_request, 2441 .syn_recv_sock = tcp_v4_syn_recv_sock, 2442 .net_header_len = sizeof(struct iphdr), 2443 .setsockopt = ip_setsockopt, 2444 .getsockopt = ip_getsockopt, 2445 .addr2sockaddr = inet_csk_addr2sockaddr, 2446 .sockaddr_len = sizeof(struct sockaddr_in), 2447 .mtu_reduced = tcp_v4_mtu_reduced, 2448 }; 2449 EXPORT_SYMBOL(ipv4_specific); 2450 2451 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) 2452 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = { 2453 #ifdef CONFIG_TCP_MD5SIG 2454 .md5_lookup = tcp_v4_md5_lookup, 2455 .calc_md5_hash = tcp_v4_md5_hash_skb, 2456 .md5_parse = tcp_v4_parse_md5_keys, 2457 #endif 2458 #ifdef CONFIG_TCP_AO 2459 .ao_lookup = tcp_v4_ao_lookup, 2460 .calc_ao_hash = tcp_v4_ao_hash_skb, 2461 .ao_parse = tcp_v4_parse_ao, 2462 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk, 2463 #endif 2464 }; 2465 #endif 2466 2467 /* NOTE: A lot of things set to zero explicitly by call to 2468 * sk_alloc() so need not be done here. 2469 */ 2470 static int tcp_v4_init_sock(struct sock *sk) 2471 { 2472 struct inet_connection_sock *icsk = inet_csk(sk); 2473 2474 tcp_init_sock(sk); 2475 2476 icsk->icsk_af_ops = &ipv4_specific; 2477 2478 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) 2479 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific; 2480 #endif 2481 2482 return 0; 2483 } 2484 2485 #ifdef CONFIG_TCP_MD5SIG 2486 static void tcp_md5sig_info_free_rcu(struct rcu_head *head) 2487 { 2488 struct tcp_md5sig_info *md5sig; 2489 2490 md5sig = container_of(head, struct tcp_md5sig_info, rcu); 2491 kfree(md5sig); 2492 static_branch_slow_dec_deferred(&tcp_md5_needed); 2493 tcp_md5_release_sigpool(); 2494 } 2495 #endif 2496 2497 void tcp_v4_destroy_sock(struct sock *sk) 2498 { 2499 struct tcp_sock *tp = tcp_sk(sk); 2500 2501 trace_tcp_destroy_sock(sk); 2502 2503 tcp_clear_xmit_timers(sk); 2504 2505 tcp_cleanup_congestion_control(sk); 2506 2507 tcp_cleanup_ulp(sk); 2508 2509 /* Cleanup up the write buffer. */ 2510 tcp_write_queue_purge(sk); 2511 2512 /* Check if we want to disable active TFO */ 2513 tcp_fastopen_active_disable_ofo_check(sk); 2514 2515 /* Cleans up our, hopefully empty, out_of_order_queue. */ 2516 skb_rbtree_purge(&tp->out_of_order_queue); 2517 2518 #ifdef CONFIG_TCP_MD5SIG 2519 /* Clean up the MD5 key list, if any */ 2520 if (tp->md5sig_info) { 2521 struct tcp_md5sig_info *md5sig; 2522 2523 md5sig = rcu_dereference_protected(tp->md5sig_info, 1); 2524 tcp_clear_md5_list(sk); 2525 call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu); 2526 rcu_assign_pointer(tp->md5sig_info, NULL); 2527 } 2528 #endif 2529 tcp_ao_destroy_sock(sk, false); 2530 2531 /* Clean up a referenced TCP bind bucket. */ 2532 if (inet_csk(sk)->icsk_bind_hash) 2533 inet_put_port(sk); 2534 2535 BUG_ON(rcu_access_pointer(tp->fastopen_rsk)); 2536 2537 /* If socket is aborted during connect operation */ 2538 tcp_free_fastopen_req(tp); 2539 tcp_fastopen_destroy_cipher(sk); 2540 tcp_saved_syn_free(tp); 2541 2542 sk_sockets_allocated_dec(sk); 2543 } 2544 EXPORT_SYMBOL(tcp_v4_destroy_sock); 2545 2546 #ifdef CONFIG_PROC_FS 2547 /* Proc filesystem TCP sock list dumping. */ 2548 2549 static unsigned short seq_file_family(const struct seq_file *seq); 2550 2551 static bool seq_sk_match(struct seq_file *seq, const struct sock *sk) 2552 { 2553 unsigned short family = seq_file_family(seq); 2554 2555 /* AF_UNSPEC is used as a match all */ 2556 return ((family == AF_UNSPEC || family == sk->sk_family) && 2557 net_eq(sock_net(sk), seq_file_net(seq))); 2558 } 2559 2560 /* Find a non empty bucket (starting from st->bucket) 2561 * and return the first sk from it. 2562 */ 2563 static void *listening_get_first(struct seq_file *seq) 2564 { 2565 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2566 struct tcp_iter_state *st = seq->private; 2567 2568 st->offset = 0; 2569 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) { 2570 struct inet_listen_hashbucket *ilb2; 2571 struct hlist_nulls_node *node; 2572 struct sock *sk; 2573 2574 ilb2 = &hinfo->lhash2[st->bucket]; 2575 if (hlist_nulls_empty(&ilb2->nulls_head)) 2576 continue; 2577 2578 spin_lock(&ilb2->lock); 2579 sk_nulls_for_each(sk, node, &ilb2->nulls_head) { 2580 if (seq_sk_match(seq, sk)) 2581 return sk; 2582 } 2583 spin_unlock(&ilb2->lock); 2584 } 2585 2586 return NULL; 2587 } 2588 2589 /* Find the next sk of "cur" within the same bucket (i.e. st->bucket). 2590 * If "cur" is the last one in the st->bucket, 2591 * call listening_get_first() to return the first sk of the next 2592 * non empty bucket. 2593 */ 2594 static void *listening_get_next(struct seq_file *seq, void *cur) 2595 { 2596 struct tcp_iter_state *st = seq->private; 2597 struct inet_listen_hashbucket *ilb2; 2598 struct hlist_nulls_node *node; 2599 struct inet_hashinfo *hinfo; 2600 struct sock *sk = cur; 2601 2602 ++st->num; 2603 ++st->offset; 2604 2605 sk = sk_nulls_next(sk); 2606 sk_nulls_for_each_from(sk, node) { 2607 if (seq_sk_match(seq, sk)) 2608 return sk; 2609 } 2610 2611 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2612 ilb2 = &hinfo->lhash2[st->bucket]; 2613 spin_unlock(&ilb2->lock); 2614 ++st->bucket; 2615 return listening_get_first(seq); 2616 } 2617 2618 static void *listening_get_idx(struct seq_file *seq, loff_t *pos) 2619 { 2620 struct tcp_iter_state *st = seq->private; 2621 void *rc; 2622 2623 st->bucket = 0; 2624 st->offset = 0; 2625 rc = listening_get_first(seq); 2626 2627 while (rc && *pos) { 2628 rc = listening_get_next(seq, rc); 2629 --*pos; 2630 } 2631 return rc; 2632 } 2633 2634 static inline bool empty_bucket(struct inet_hashinfo *hinfo, 2635 const struct tcp_iter_state *st) 2636 { 2637 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain); 2638 } 2639 2640 /* 2641 * Get first established socket starting from bucket given in st->bucket. 2642 * If st->bucket is zero, the very first socket in the hash is returned. 2643 */ 2644 static void *established_get_first(struct seq_file *seq) 2645 { 2646 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2647 struct tcp_iter_state *st = seq->private; 2648 2649 st->offset = 0; 2650 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) { 2651 struct sock *sk; 2652 struct hlist_nulls_node *node; 2653 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket); 2654 2655 cond_resched(); 2656 2657 /* Lockless fast path for the common case of empty buckets */ 2658 if (empty_bucket(hinfo, st)) 2659 continue; 2660 2661 spin_lock_bh(lock); 2662 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) { 2663 if (seq_sk_match(seq, sk)) 2664 return sk; 2665 } 2666 spin_unlock_bh(lock); 2667 } 2668 2669 return NULL; 2670 } 2671 2672 static void *established_get_next(struct seq_file *seq, void *cur) 2673 { 2674 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2675 struct tcp_iter_state *st = seq->private; 2676 struct hlist_nulls_node *node; 2677 struct sock *sk = cur; 2678 2679 ++st->num; 2680 ++st->offset; 2681 2682 sk = sk_nulls_next(sk); 2683 2684 sk_nulls_for_each_from(sk, node) { 2685 if (seq_sk_match(seq, sk)) 2686 return sk; 2687 } 2688 2689 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket)); 2690 ++st->bucket; 2691 return established_get_first(seq); 2692 } 2693 2694 static void *established_get_idx(struct seq_file *seq, loff_t pos) 2695 { 2696 struct tcp_iter_state *st = seq->private; 2697 void *rc; 2698 2699 st->bucket = 0; 2700 rc = established_get_first(seq); 2701 2702 while (rc && pos) { 2703 rc = established_get_next(seq, rc); 2704 --pos; 2705 } 2706 return rc; 2707 } 2708 2709 static void *tcp_get_idx(struct seq_file *seq, loff_t pos) 2710 { 2711 void *rc; 2712 struct tcp_iter_state *st = seq->private; 2713 2714 st->state = TCP_SEQ_STATE_LISTENING; 2715 rc = listening_get_idx(seq, &pos); 2716 2717 if (!rc) { 2718 st->state = TCP_SEQ_STATE_ESTABLISHED; 2719 rc = established_get_idx(seq, pos); 2720 } 2721 2722 return rc; 2723 } 2724 2725 static void *tcp_seek_last_pos(struct seq_file *seq) 2726 { 2727 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2728 struct tcp_iter_state *st = seq->private; 2729 int bucket = st->bucket; 2730 int offset = st->offset; 2731 int orig_num = st->num; 2732 void *rc = NULL; 2733 2734 switch (st->state) { 2735 case TCP_SEQ_STATE_LISTENING: 2736 if (st->bucket > hinfo->lhash2_mask) 2737 break; 2738 rc = listening_get_first(seq); 2739 while (offset-- && rc && bucket == st->bucket) 2740 rc = listening_get_next(seq, rc); 2741 if (rc) 2742 break; 2743 st->bucket = 0; 2744 st->state = TCP_SEQ_STATE_ESTABLISHED; 2745 fallthrough; 2746 case TCP_SEQ_STATE_ESTABLISHED: 2747 if (st->bucket > hinfo->ehash_mask) 2748 break; 2749 rc = established_get_first(seq); 2750 while (offset-- && rc && bucket == st->bucket) 2751 rc = established_get_next(seq, rc); 2752 } 2753 2754 st->num = orig_num; 2755 2756 return rc; 2757 } 2758 2759 void *tcp_seq_start(struct seq_file *seq, loff_t *pos) 2760 { 2761 struct tcp_iter_state *st = seq->private; 2762 void *rc; 2763 2764 if (*pos && *pos == st->last_pos) { 2765 rc = tcp_seek_last_pos(seq); 2766 if (rc) 2767 goto out; 2768 } 2769 2770 st->state = TCP_SEQ_STATE_LISTENING; 2771 st->num = 0; 2772 st->bucket = 0; 2773 st->offset = 0; 2774 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; 2775 2776 out: 2777 st->last_pos = *pos; 2778 return rc; 2779 } 2780 EXPORT_SYMBOL(tcp_seq_start); 2781 2782 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2783 { 2784 struct tcp_iter_state *st = seq->private; 2785 void *rc = NULL; 2786 2787 if (v == SEQ_START_TOKEN) { 2788 rc = tcp_get_idx(seq, 0); 2789 goto out; 2790 } 2791 2792 switch (st->state) { 2793 case TCP_SEQ_STATE_LISTENING: 2794 rc = listening_get_next(seq, v); 2795 if (!rc) { 2796 st->state = TCP_SEQ_STATE_ESTABLISHED; 2797 st->bucket = 0; 2798 st->offset = 0; 2799 rc = established_get_first(seq); 2800 } 2801 break; 2802 case TCP_SEQ_STATE_ESTABLISHED: 2803 rc = established_get_next(seq, v); 2804 break; 2805 } 2806 out: 2807 ++*pos; 2808 st->last_pos = *pos; 2809 return rc; 2810 } 2811 EXPORT_SYMBOL(tcp_seq_next); 2812 2813 void tcp_seq_stop(struct seq_file *seq, void *v) 2814 { 2815 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2816 struct tcp_iter_state *st = seq->private; 2817 2818 switch (st->state) { 2819 case TCP_SEQ_STATE_LISTENING: 2820 if (v != SEQ_START_TOKEN) 2821 spin_unlock(&hinfo->lhash2[st->bucket].lock); 2822 break; 2823 case TCP_SEQ_STATE_ESTABLISHED: 2824 if (v) 2825 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket)); 2826 break; 2827 } 2828 } 2829 EXPORT_SYMBOL(tcp_seq_stop); 2830 2831 static void get_openreq4(const struct request_sock *req, 2832 struct seq_file *f, int i) 2833 { 2834 const struct inet_request_sock *ireq = inet_rsk(req); 2835 long delta = req->rsk_timer.expires - jiffies; 2836 2837 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2838 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK", 2839 i, 2840 ireq->ir_loc_addr, 2841 ireq->ir_num, 2842 ireq->ir_rmt_addr, 2843 ntohs(ireq->ir_rmt_port), 2844 TCP_SYN_RECV, 2845 0, 0, /* could print option size, but that is af dependent. */ 2846 1, /* timers active (only the expire timer) */ 2847 jiffies_delta_to_clock_t(delta), 2848 req->num_timeout, 2849 from_kuid_munged(seq_user_ns(f), 2850 sock_i_uid(req->rsk_listener)), 2851 0, /* non standard timer */ 2852 0, /* open_requests have no inode */ 2853 0, 2854 req); 2855 } 2856 2857 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i) 2858 { 2859 int timer_active; 2860 unsigned long timer_expires; 2861 const struct tcp_sock *tp = tcp_sk(sk); 2862 const struct inet_connection_sock *icsk = inet_csk(sk); 2863 const struct inet_sock *inet = inet_sk(sk); 2864 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq; 2865 __be32 dest = inet->inet_daddr; 2866 __be32 src = inet->inet_rcv_saddr; 2867 __u16 destp = ntohs(inet->inet_dport); 2868 __u16 srcp = ntohs(inet->inet_sport); 2869 int rx_queue; 2870 int state; 2871 2872 if (icsk->icsk_pending == ICSK_TIME_RETRANS || 2873 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT || 2874 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { 2875 timer_active = 1; 2876 timer_expires = icsk->icsk_timeout; 2877 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { 2878 timer_active = 4; 2879 timer_expires = icsk->icsk_timeout; 2880 } else if (timer_pending(&sk->sk_timer)) { 2881 timer_active = 2; 2882 timer_expires = sk->sk_timer.expires; 2883 } else { 2884 timer_active = 0; 2885 timer_expires = jiffies; 2886 } 2887 2888 state = inet_sk_state_load(sk); 2889 if (state == TCP_LISTEN) 2890 rx_queue = READ_ONCE(sk->sk_ack_backlog); 2891 else 2892 /* Because we don't lock the socket, 2893 * we might find a transient negative value. 2894 */ 2895 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) - 2896 READ_ONCE(tp->copied_seq), 0); 2897 2898 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " 2899 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d", 2900 i, src, srcp, dest, destp, state, 2901 READ_ONCE(tp->write_seq) - tp->snd_una, 2902 rx_queue, 2903 timer_active, 2904 jiffies_delta_to_clock_t(timer_expires - jiffies), 2905 icsk->icsk_retransmits, 2906 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)), 2907 icsk->icsk_probes_out, 2908 sock_i_ino(sk), 2909 refcount_read(&sk->sk_refcnt), sk, 2910 jiffies_to_clock_t(icsk->icsk_rto), 2911 jiffies_to_clock_t(icsk->icsk_ack.ato), 2912 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk), 2913 tcp_snd_cwnd(tp), 2914 state == TCP_LISTEN ? 2915 fastopenq->max_qlen : 2916 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)); 2917 } 2918 2919 static void get_timewait4_sock(const struct inet_timewait_sock *tw, 2920 struct seq_file *f, int i) 2921 { 2922 long delta = tw->tw_timer.expires - jiffies; 2923 __be32 dest, src; 2924 __u16 destp, srcp; 2925 2926 dest = tw->tw_daddr; 2927 src = tw->tw_rcv_saddr; 2928 destp = ntohs(tw->tw_dport); 2929 srcp = ntohs(tw->tw_sport); 2930 2931 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2932 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK", 2933 i, src, srcp, dest, destp, tw->tw_substate, 0, 0, 2934 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, 2935 refcount_read(&tw->tw_refcnt), tw); 2936 } 2937 2938 #define TMPSZ 150 2939 2940 static int tcp4_seq_show(struct seq_file *seq, void *v) 2941 { 2942 struct tcp_iter_state *st; 2943 struct sock *sk = v; 2944 2945 seq_setwidth(seq, TMPSZ - 1); 2946 if (v == SEQ_START_TOKEN) { 2947 seq_puts(seq, " sl local_address rem_address st tx_queue " 2948 "rx_queue tr tm->when retrnsmt uid timeout " 2949 "inode"); 2950 goto out; 2951 } 2952 st = seq->private; 2953 2954 if (sk->sk_state == TCP_TIME_WAIT) 2955 get_timewait4_sock(v, seq, st->num); 2956 else if (sk->sk_state == TCP_NEW_SYN_RECV) 2957 get_openreq4(v, seq, st->num); 2958 else 2959 get_tcp4_sock(v, seq, st->num); 2960 out: 2961 seq_pad(seq, '\n'); 2962 return 0; 2963 } 2964 2965 #ifdef CONFIG_BPF_SYSCALL 2966 struct bpf_tcp_iter_state { 2967 struct tcp_iter_state state; 2968 unsigned int cur_sk; 2969 unsigned int end_sk; 2970 unsigned int max_sk; 2971 struct sock **batch; 2972 bool st_bucket_done; 2973 }; 2974 2975 struct bpf_iter__tcp { 2976 __bpf_md_ptr(struct bpf_iter_meta *, meta); 2977 __bpf_md_ptr(struct sock_common *, sk_common); 2978 uid_t uid __aligned(8); 2979 }; 2980 2981 static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta, 2982 struct sock_common *sk_common, uid_t uid) 2983 { 2984 struct bpf_iter__tcp ctx; 2985 2986 meta->seq_num--; /* skip SEQ_START_TOKEN */ 2987 ctx.meta = meta; 2988 ctx.sk_common = sk_common; 2989 ctx.uid = uid; 2990 return bpf_iter_run_prog(prog, &ctx); 2991 } 2992 2993 static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter) 2994 { 2995 while (iter->cur_sk < iter->end_sk) 2996 sock_gen_put(iter->batch[iter->cur_sk++]); 2997 } 2998 2999 static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter, 3000 unsigned int new_batch_sz) 3001 { 3002 struct sock **new_batch; 3003 3004 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz, 3005 GFP_USER | __GFP_NOWARN); 3006 if (!new_batch) 3007 return -ENOMEM; 3008 3009 bpf_iter_tcp_put_batch(iter); 3010 kvfree(iter->batch); 3011 iter->batch = new_batch; 3012 iter->max_sk = new_batch_sz; 3013 3014 return 0; 3015 } 3016 3017 static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq, 3018 struct sock *start_sk) 3019 { 3020 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 3021 struct bpf_tcp_iter_state *iter = seq->private; 3022 struct tcp_iter_state *st = &iter->state; 3023 struct hlist_nulls_node *node; 3024 unsigned int expected = 1; 3025 struct sock *sk; 3026 3027 sock_hold(start_sk); 3028 iter->batch[iter->end_sk++] = start_sk; 3029 3030 sk = sk_nulls_next(start_sk); 3031 sk_nulls_for_each_from(sk, node) { 3032 if (seq_sk_match(seq, sk)) { 3033 if (iter->end_sk < iter->max_sk) { 3034 sock_hold(sk); 3035 iter->batch[iter->end_sk++] = sk; 3036 } 3037 expected++; 3038 } 3039 } 3040 spin_unlock(&hinfo->lhash2[st->bucket].lock); 3041 3042 return expected; 3043 } 3044 3045 static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq, 3046 struct sock *start_sk) 3047 { 3048 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 3049 struct bpf_tcp_iter_state *iter = seq->private; 3050 struct tcp_iter_state *st = &iter->state; 3051 struct hlist_nulls_node *node; 3052 unsigned int expected = 1; 3053 struct sock *sk; 3054 3055 sock_hold(start_sk); 3056 iter->batch[iter->end_sk++] = start_sk; 3057 3058 sk = sk_nulls_next(start_sk); 3059 sk_nulls_for_each_from(sk, node) { 3060 if (seq_sk_match(seq, sk)) { 3061 if (iter->end_sk < iter->max_sk) { 3062 sock_hold(sk); 3063 iter->batch[iter->end_sk++] = sk; 3064 } 3065 expected++; 3066 } 3067 } 3068 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket)); 3069 3070 return expected; 3071 } 3072 3073 static struct sock *bpf_iter_tcp_batch(struct seq_file *seq) 3074 { 3075 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 3076 struct bpf_tcp_iter_state *iter = seq->private; 3077 struct tcp_iter_state *st = &iter->state; 3078 unsigned int expected; 3079 bool resized = false; 3080 struct sock *sk; 3081 3082 /* The st->bucket is done. Directly advance to the next 3083 * bucket instead of having the tcp_seek_last_pos() to skip 3084 * one by one in the current bucket and eventually find out 3085 * it has to advance to the next bucket. 3086 */ 3087 if (iter->st_bucket_done) { 3088 st->offset = 0; 3089 st->bucket++; 3090 if (st->state == TCP_SEQ_STATE_LISTENING && 3091 st->bucket > hinfo->lhash2_mask) { 3092 st->state = TCP_SEQ_STATE_ESTABLISHED; 3093 st->bucket = 0; 3094 } 3095 } 3096 3097 again: 3098 /* Get a new batch */ 3099 iter->cur_sk = 0; 3100 iter->end_sk = 0; 3101 iter->st_bucket_done = false; 3102 3103 sk = tcp_seek_last_pos(seq); 3104 if (!sk) 3105 return NULL; /* Done */ 3106 3107 if (st->state == TCP_SEQ_STATE_LISTENING) 3108 expected = bpf_iter_tcp_listening_batch(seq, sk); 3109 else 3110 expected = bpf_iter_tcp_established_batch(seq, sk); 3111 3112 if (iter->end_sk == expected) { 3113 iter->st_bucket_done = true; 3114 return sk; 3115 } 3116 3117 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) { 3118 resized = true; 3119 goto again; 3120 } 3121 3122 return sk; 3123 } 3124 3125 static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos) 3126 { 3127 /* bpf iter does not support lseek, so it always 3128 * continue from where it was stop()-ped. 3129 */ 3130 if (*pos) 3131 return bpf_iter_tcp_batch(seq); 3132 3133 return SEQ_START_TOKEN; 3134 } 3135 3136 static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 3137 { 3138 struct bpf_tcp_iter_state *iter = seq->private; 3139 struct tcp_iter_state *st = &iter->state; 3140 struct sock *sk; 3141 3142 /* Whenever seq_next() is called, the iter->cur_sk is 3143 * done with seq_show(), so advance to the next sk in 3144 * the batch. 3145 */ 3146 if (iter->cur_sk < iter->end_sk) { 3147 /* Keeping st->num consistent in tcp_iter_state. 3148 * bpf_iter_tcp does not use st->num. 3149 * meta.seq_num is used instead. 3150 */ 3151 st->num++; 3152 /* Move st->offset to the next sk in the bucket such that 3153 * the future start() will resume at st->offset in 3154 * st->bucket. See tcp_seek_last_pos(). 3155 */ 3156 st->offset++; 3157 sock_gen_put(iter->batch[iter->cur_sk++]); 3158 } 3159 3160 if (iter->cur_sk < iter->end_sk) 3161 sk = iter->batch[iter->cur_sk]; 3162 else 3163 sk = bpf_iter_tcp_batch(seq); 3164 3165 ++*pos; 3166 /* Keeping st->last_pos consistent in tcp_iter_state. 3167 * bpf iter does not do lseek, so st->last_pos always equals to *pos. 3168 */ 3169 st->last_pos = *pos; 3170 return sk; 3171 } 3172 3173 static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v) 3174 { 3175 struct bpf_iter_meta meta; 3176 struct bpf_prog *prog; 3177 struct sock *sk = v; 3178 uid_t uid; 3179 int ret; 3180 3181 if (v == SEQ_START_TOKEN) 3182 return 0; 3183 3184 if (sk_fullsock(sk)) 3185 lock_sock(sk); 3186 3187 if (unlikely(sk_unhashed(sk))) { 3188 ret = SEQ_SKIP; 3189 goto unlock; 3190 } 3191 3192 if (sk->sk_state == TCP_TIME_WAIT) { 3193 uid = 0; 3194 } else if (sk->sk_state == TCP_NEW_SYN_RECV) { 3195 const struct request_sock *req = v; 3196 3197 uid = from_kuid_munged(seq_user_ns(seq), 3198 sock_i_uid(req->rsk_listener)); 3199 } else { 3200 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)); 3201 } 3202 3203 meta.seq = seq; 3204 prog = bpf_iter_get_info(&meta, false); 3205 ret = tcp_prog_seq_show(prog, &meta, v, uid); 3206 3207 unlock: 3208 if (sk_fullsock(sk)) 3209 release_sock(sk); 3210 return ret; 3211 3212 } 3213 3214 static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v) 3215 { 3216 struct bpf_tcp_iter_state *iter = seq->private; 3217 struct bpf_iter_meta meta; 3218 struct bpf_prog *prog; 3219 3220 if (!v) { 3221 meta.seq = seq; 3222 prog = bpf_iter_get_info(&meta, true); 3223 if (prog) 3224 (void)tcp_prog_seq_show(prog, &meta, v, 0); 3225 } 3226 3227 if (iter->cur_sk < iter->end_sk) { 3228 bpf_iter_tcp_put_batch(iter); 3229 iter->st_bucket_done = false; 3230 } 3231 } 3232 3233 static const struct seq_operations bpf_iter_tcp_seq_ops = { 3234 .show = bpf_iter_tcp_seq_show, 3235 .start = bpf_iter_tcp_seq_start, 3236 .next = bpf_iter_tcp_seq_next, 3237 .stop = bpf_iter_tcp_seq_stop, 3238 }; 3239 #endif 3240 static unsigned short seq_file_family(const struct seq_file *seq) 3241 { 3242 const struct tcp_seq_afinfo *afinfo; 3243 3244 #ifdef CONFIG_BPF_SYSCALL 3245 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */ 3246 if (seq->op == &bpf_iter_tcp_seq_ops) 3247 return AF_UNSPEC; 3248 #endif 3249 3250 /* Iterated from proc fs */ 3251 afinfo = pde_data(file_inode(seq->file)); 3252 return afinfo->family; 3253 } 3254 3255 static const struct seq_operations tcp4_seq_ops = { 3256 .show = tcp4_seq_show, 3257 .start = tcp_seq_start, 3258 .next = tcp_seq_next, 3259 .stop = tcp_seq_stop, 3260 }; 3261 3262 static struct tcp_seq_afinfo tcp4_seq_afinfo = { 3263 .family = AF_INET, 3264 }; 3265 3266 static int __net_init tcp4_proc_init_net(struct net *net) 3267 { 3268 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops, 3269 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo)) 3270 return -ENOMEM; 3271 return 0; 3272 } 3273 3274 static void __net_exit tcp4_proc_exit_net(struct net *net) 3275 { 3276 remove_proc_entry("tcp", net->proc_net); 3277 } 3278 3279 static struct pernet_operations tcp4_net_ops = { 3280 .init = tcp4_proc_init_net, 3281 .exit = tcp4_proc_exit_net, 3282 }; 3283 3284 int __init tcp4_proc_init(void) 3285 { 3286 return register_pernet_subsys(&tcp4_net_ops); 3287 } 3288 3289 void tcp4_proc_exit(void) 3290 { 3291 unregister_pernet_subsys(&tcp4_net_ops); 3292 } 3293 #endif /* CONFIG_PROC_FS */ 3294 3295 /* @wake is one when sk_stream_write_space() calls us. 3296 * This sends EPOLLOUT only if notsent_bytes is half the limit. 3297 * This mimics the strategy used in sock_def_write_space(). 3298 */ 3299 bool tcp_stream_memory_free(const struct sock *sk, int wake) 3300 { 3301 const struct tcp_sock *tp = tcp_sk(sk); 3302 u32 notsent_bytes = READ_ONCE(tp->write_seq) - 3303 READ_ONCE(tp->snd_nxt); 3304 3305 return (notsent_bytes << wake) < tcp_notsent_lowat(tp); 3306 } 3307 EXPORT_SYMBOL(tcp_stream_memory_free); 3308 3309 struct proto tcp_prot = { 3310 .name = "TCP", 3311 .owner = THIS_MODULE, 3312 .close = tcp_close, 3313 .pre_connect = tcp_v4_pre_connect, 3314 .connect = tcp_v4_connect, 3315 .disconnect = tcp_disconnect, 3316 .accept = inet_csk_accept, 3317 .ioctl = tcp_ioctl, 3318 .init = tcp_v4_init_sock, 3319 .destroy = tcp_v4_destroy_sock, 3320 .shutdown = tcp_shutdown, 3321 .setsockopt = tcp_setsockopt, 3322 .getsockopt = tcp_getsockopt, 3323 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt, 3324 .keepalive = tcp_set_keepalive, 3325 .recvmsg = tcp_recvmsg, 3326 .sendmsg = tcp_sendmsg, 3327 .splice_eof = tcp_splice_eof, 3328 .backlog_rcv = tcp_v4_do_rcv, 3329 .release_cb = tcp_release_cb, 3330 .hash = inet_hash, 3331 .unhash = inet_unhash, 3332 .get_port = inet_csk_get_port, 3333 .put_port = inet_put_port, 3334 #ifdef CONFIG_BPF_SYSCALL 3335 .psock_update_sk_prot = tcp_bpf_update_proto, 3336 #endif 3337 .enter_memory_pressure = tcp_enter_memory_pressure, 3338 .leave_memory_pressure = tcp_leave_memory_pressure, 3339 .stream_memory_free = tcp_stream_memory_free, 3340 .sockets_allocated = &tcp_sockets_allocated, 3341 .orphan_count = &tcp_orphan_count, 3342 3343 .memory_allocated = &tcp_memory_allocated, 3344 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc, 3345 3346 .memory_pressure = &tcp_memory_pressure, 3347 .sysctl_mem = sysctl_tcp_mem, 3348 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 3349 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), 3350 .max_header = MAX_TCP_HEADER, 3351 .obj_size = sizeof(struct tcp_sock), 3352 .slab_flags = SLAB_TYPESAFE_BY_RCU, 3353 .twsk_prot = &tcp_timewait_sock_ops, 3354 .rsk_prot = &tcp_request_sock_ops, 3355 .h.hashinfo = NULL, 3356 .no_autobind = true, 3357 .diag_destroy = tcp_abort, 3358 }; 3359 EXPORT_SYMBOL(tcp_prot); 3360 3361 static void __net_exit tcp_sk_exit(struct net *net) 3362 { 3363 if (net->ipv4.tcp_congestion_control) 3364 bpf_module_put(net->ipv4.tcp_congestion_control, 3365 net->ipv4.tcp_congestion_control->owner); 3366 } 3367 3368 static void __net_init tcp_set_hashinfo(struct net *net) 3369 { 3370 struct inet_hashinfo *hinfo; 3371 unsigned int ehash_entries; 3372 struct net *old_net; 3373 3374 if (net_eq(net, &init_net)) 3375 goto fallback; 3376 3377 old_net = current->nsproxy->net_ns; 3378 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries); 3379 if (!ehash_entries) 3380 goto fallback; 3381 3382 ehash_entries = roundup_pow_of_two(ehash_entries); 3383 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries); 3384 if (!hinfo) { 3385 pr_warn("Failed to allocate TCP ehash (entries: %u) " 3386 "for a netns, fallback to the global one\n", 3387 ehash_entries); 3388 fallback: 3389 hinfo = &tcp_hashinfo; 3390 ehash_entries = tcp_hashinfo.ehash_mask + 1; 3391 } 3392 3393 net->ipv4.tcp_death_row.hashinfo = hinfo; 3394 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2; 3395 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128); 3396 } 3397 3398 static int __net_init tcp_sk_init(struct net *net) 3399 { 3400 net->ipv4.sysctl_tcp_ecn = 2; 3401 net->ipv4.sysctl_tcp_ecn_fallback = 1; 3402 3403 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS; 3404 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS; 3405 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD; 3406 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL; 3407 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS; 3408 3409 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME; 3410 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES; 3411 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL; 3412 3413 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES; 3414 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES; 3415 net->ipv4.sysctl_tcp_syncookies = 1; 3416 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH; 3417 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1; 3418 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2; 3419 net->ipv4.sysctl_tcp_orphan_retries = 0; 3420 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT; 3421 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX; 3422 net->ipv4.sysctl_tcp_tw_reuse = 2; 3423 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1; 3424 3425 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1); 3426 tcp_set_hashinfo(net); 3427 3428 net->ipv4.sysctl_tcp_sack = 1; 3429 net->ipv4.sysctl_tcp_window_scaling = 1; 3430 net->ipv4.sysctl_tcp_timestamps = 1; 3431 net->ipv4.sysctl_tcp_early_retrans = 3; 3432 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION; 3433 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */ 3434 net->ipv4.sysctl_tcp_retrans_collapse = 1; 3435 net->ipv4.sysctl_tcp_max_reordering = 300; 3436 net->ipv4.sysctl_tcp_dsack = 1; 3437 net->ipv4.sysctl_tcp_app_win = 31; 3438 net->ipv4.sysctl_tcp_adv_win_scale = 1; 3439 net->ipv4.sysctl_tcp_frto = 2; 3440 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1; 3441 /* This limits the percentage of the congestion window which we 3442 * will allow a single TSO frame to consume. Building TSO frames 3443 * which are too large can cause TCP streams to be bursty. 3444 */ 3445 net->ipv4.sysctl_tcp_tso_win_divisor = 3; 3446 /* Default TSQ limit of 16 TSO segments */ 3447 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536; 3448 3449 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */ 3450 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX; 3451 3452 net->ipv4.sysctl_tcp_min_tso_segs = 2; 3453 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */ 3454 net->ipv4.sysctl_tcp_min_rtt_wlen = 300; 3455 net->ipv4.sysctl_tcp_autocorking = 1; 3456 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2; 3457 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200; 3458 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120; 3459 if (net != &init_net) { 3460 memcpy(net->ipv4.sysctl_tcp_rmem, 3461 init_net.ipv4.sysctl_tcp_rmem, 3462 sizeof(init_net.ipv4.sysctl_tcp_rmem)); 3463 memcpy(net->ipv4.sysctl_tcp_wmem, 3464 init_net.ipv4.sysctl_tcp_wmem, 3465 sizeof(init_net.ipv4.sysctl_tcp_wmem)); 3466 } 3467 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC; 3468 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC; 3469 net->ipv4.sysctl_tcp_comp_sack_nr = 44; 3470 net->ipv4.sysctl_tcp_backlog_ack_defer = 1; 3471 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE; 3472 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0; 3473 atomic_set(&net->ipv4.tfo_active_disable_times, 0); 3474 3475 /* Set default values for PLB */ 3476 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */ 3477 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3; 3478 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12; 3479 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60; 3480 /* Default congestion threshold for PLB to mark a round is 50% */ 3481 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2; 3482 3483 /* Reno is always built in */ 3484 if (!net_eq(net, &init_net) && 3485 bpf_try_module_get(init_net.ipv4.tcp_congestion_control, 3486 init_net.ipv4.tcp_congestion_control->owner)) 3487 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control; 3488 else 3489 net->ipv4.tcp_congestion_control = &tcp_reno; 3490 3491 net->ipv4.sysctl_tcp_syn_linear_timeouts = 4; 3492 net->ipv4.sysctl_tcp_shrink_window = 0; 3493 3494 net->ipv4.sysctl_tcp_pingpong_thresh = 1; 3495 3496 return 0; 3497 } 3498 3499 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list) 3500 { 3501 struct net *net; 3502 3503 tcp_twsk_purge(net_exit_list); 3504 3505 list_for_each_entry(net, net_exit_list, exit_list) { 3506 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo); 3507 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount)); 3508 tcp_fastopen_ctx_destroy(net); 3509 } 3510 } 3511 3512 static struct pernet_operations __net_initdata tcp_sk_ops = { 3513 .init = tcp_sk_init, 3514 .exit = tcp_sk_exit, 3515 .exit_batch = tcp_sk_exit_batch, 3516 }; 3517 3518 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 3519 DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta, 3520 struct sock_common *sk_common, uid_t uid) 3521 3522 #define INIT_BATCH_SZ 16 3523 3524 static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux) 3525 { 3526 struct bpf_tcp_iter_state *iter = priv_data; 3527 int err; 3528 3529 err = bpf_iter_init_seq_net(priv_data, aux); 3530 if (err) 3531 return err; 3532 3533 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ); 3534 if (err) { 3535 bpf_iter_fini_seq_net(priv_data); 3536 return err; 3537 } 3538 3539 return 0; 3540 } 3541 3542 static void bpf_iter_fini_tcp(void *priv_data) 3543 { 3544 struct bpf_tcp_iter_state *iter = priv_data; 3545 3546 bpf_iter_fini_seq_net(priv_data); 3547 kvfree(iter->batch); 3548 } 3549 3550 static const struct bpf_iter_seq_info tcp_seq_info = { 3551 .seq_ops = &bpf_iter_tcp_seq_ops, 3552 .init_seq_private = bpf_iter_init_tcp, 3553 .fini_seq_private = bpf_iter_fini_tcp, 3554 .seq_priv_size = sizeof(struct bpf_tcp_iter_state), 3555 }; 3556 3557 static const struct bpf_func_proto * 3558 bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id, 3559 const struct bpf_prog *prog) 3560 { 3561 switch (func_id) { 3562 case BPF_FUNC_setsockopt: 3563 return &bpf_sk_setsockopt_proto; 3564 case BPF_FUNC_getsockopt: 3565 return &bpf_sk_getsockopt_proto; 3566 default: 3567 return NULL; 3568 } 3569 } 3570 3571 static struct bpf_iter_reg tcp_reg_info = { 3572 .target = "tcp", 3573 .ctx_arg_info_size = 1, 3574 .ctx_arg_info = { 3575 { offsetof(struct bpf_iter__tcp, sk_common), 3576 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED }, 3577 }, 3578 .get_func_proto = bpf_iter_tcp_get_func_proto, 3579 .seq_info = &tcp_seq_info, 3580 }; 3581 3582 static void __init bpf_iter_register(void) 3583 { 3584 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON]; 3585 if (bpf_iter_reg_target(&tcp_reg_info)) 3586 pr_warn("Warning: could not register bpf iterator tcp\n"); 3587 } 3588 3589 #endif 3590 3591 void __init tcp_v4_init(void) 3592 { 3593 int cpu, res; 3594 3595 for_each_possible_cpu(cpu) { 3596 struct sock *sk; 3597 3598 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW, 3599 IPPROTO_TCP, &init_net); 3600 if (res) 3601 panic("Failed to create the TCP control socket.\n"); 3602 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 3603 3604 /* Please enforce IP_DF and IPID==0 for RST and 3605 * ACK sent in SYN-RECV and TIME-WAIT state. 3606 */ 3607 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO; 3608 3609 per_cpu(ipv4_tcp_sk, cpu) = sk; 3610 } 3611 if (register_pernet_subsys(&tcp_sk_ops)) 3612 panic("Failed to create the TCP control socket.\n"); 3613 3614 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 3615 bpf_iter_register(); 3616 #endif 3617 } 3618