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 if (sk_fullsock(sk)) 872 trace_tcp_send_reset(sk, skb); 873 } 874 875 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) != 876 offsetof(struct inet_timewait_sock, tw_bound_dev_if)); 877 878 arg.tos = ip_hdr(skb)->tos; 879 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL); 880 local_bh_disable(); 881 ctl_sk = this_cpu_read(ipv4_tcp_sk); 882 sock_net_set(ctl_sk, net); 883 if (sk) { 884 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ? 885 inet_twsk(sk)->tw_mark : sk->sk_mark; 886 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ? 887 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority); 888 transmit_time = tcp_transmit_time(sk); 889 xfrm_sk_clone_policy(ctl_sk, sk); 890 txhash = (sk->sk_state == TCP_TIME_WAIT) ? 891 inet_twsk(sk)->tw_txhash : sk->sk_txhash; 892 } else { 893 ctl_sk->sk_mark = 0; 894 ctl_sk->sk_priority = 0; 895 } 896 ip_send_unicast_reply(ctl_sk, 897 skb, &TCP_SKB_CB(skb)->header.h4.opt, 898 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 899 &arg, arg.iov[0].iov_len, 900 transmit_time, txhash); 901 902 xfrm_sk_free_policy(ctl_sk); 903 sock_net_set(ctl_sk, &init_net); 904 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); 905 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS); 906 local_bh_enable(); 907 908 #ifdef CONFIG_TCP_MD5SIG 909 out: 910 rcu_read_unlock(); 911 #endif 912 } 913 914 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states 915 outside socket context is ugly, certainly. What can I do? 916 */ 917 918 static void tcp_v4_send_ack(const struct sock *sk, 919 struct sk_buff *skb, u32 seq, u32 ack, 920 u32 win, u32 tsval, u32 tsecr, int oif, 921 struct tcp_key *key, 922 int reply_flags, u8 tos, u32 txhash) 923 { 924 const struct tcphdr *th = tcp_hdr(skb); 925 struct { 926 struct tcphdr th; 927 __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)]; 928 } rep; 929 struct net *net = sock_net(sk); 930 struct ip_reply_arg arg; 931 struct sock *ctl_sk; 932 u64 transmit_time; 933 934 memset(&rep.th, 0, sizeof(struct tcphdr)); 935 memset(&arg, 0, sizeof(arg)); 936 937 arg.iov[0].iov_base = (unsigned char *)&rep; 938 arg.iov[0].iov_len = sizeof(rep.th); 939 if (tsecr) { 940 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 941 (TCPOPT_TIMESTAMP << 8) | 942 TCPOLEN_TIMESTAMP); 943 rep.opt[1] = htonl(tsval); 944 rep.opt[2] = htonl(tsecr); 945 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED; 946 } 947 948 /* Swap the send and the receive. */ 949 rep.th.dest = th->source; 950 rep.th.source = th->dest; 951 rep.th.doff = arg.iov[0].iov_len / 4; 952 rep.th.seq = htonl(seq); 953 rep.th.ack_seq = htonl(ack); 954 rep.th.ack = 1; 955 rep.th.window = htons(win); 956 957 #ifdef CONFIG_TCP_MD5SIG 958 if (tcp_key_is_md5(key)) { 959 int offset = (tsecr) ? 3 : 0; 960 961 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) | 962 (TCPOPT_NOP << 16) | 963 (TCPOPT_MD5SIG << 8) | 964 TCPOLEN_MD5SIG); 965 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 966 rep.th.doff = arg.iov[0].iov_len/4; 967 968 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset], 969 key->md5_key, ip_hdr(skb)->saddr, 970 ip_hdr(skb)->daddr, &rep.th); 971 } 972 #endif 973 #ifdef CONFIG_TCP_AO 974 if (tcp_key_is_ao(key)) { 975 int offset = (tsecr) ? 3 : 0; 976 977 rep.opt[offset++] = htonl((TCPOPT_AO << 24) | 978 (tcp_ao_len(key->ao_key) << 16) | 979 (key->ao_key->sndid << 8) | 980 key->rcv_next); 981 arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key); 982 rep.th.doff = arg.iov[0].iov_len / 4; 983 984 tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset], 985 key->ao_key, key->traffic_key, 986 (union tcp_ao_addr *)&ip_hdr(skb)->saddr, 987 (union tcp_ao_addr *)&ip_hdr(skb)->daddr, 988 &rep.th, key->sne); 989 } 990 #endif 991 arg.flags = reply_flags; 992 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 993 ip_hdr(skb)->saddr, /* XXX */ 994 arg.iov[0].iov_len, IPPROTO_TCP, 0); 995 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 996 if (oif) 997 arg.bound_dev_if = oif; 998 arg.tos = tos; 999 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL); 1000 local_bh_disable(); 1001 ctl_sk = this_cpu_read(ipv4_tcp_sk); 1002 sock_net_set(ctl_sk, net); 1003 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ? 1004 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark); 1005 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ? 1006 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority); 1007 transmit_time = tcp_transmit_time(sk); 1008 ip_send_unicast_reply(ctl_sk, 1009 skb, &TCP_SKB_CB(skb)->header.h4.opt, 1010 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 1011 &arg, arg.iov[0].iov_len, 1012 transmit_time, txhash); 1013 1014 sock_net_set(ctl_sk, &init_net); 1015 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); 1016 local_bh_enable(); 1017 } 1018 1019 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) 1020 { 1021 struct inet_timewait_sock *tw = inet_twsk(sk); 1022 struct tcp_timewait_sock *tcptw = tcp_twsk(sk); 1023 struct tcp_key key = {}; 1024 #ifdef CONFIG_TCP_AO 1025 struct tcp_ao_info *ao_info; 1026 1027 if (static_branch_unlikely(&tcp_ao_needed.key)) { 1028 /* FIXME: the segment to-be-acked is not verified yet */ 1029 ao_info = rcu_dereference(tcptw->ao_info); 1030 if (ao_info) { 1031 const struct tcp_ao_hdr *aoh; 1032 1033 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) { 1034 inet_twsk_put(tw); 1035 return; 1036 } 1037 1038 if (aoh) 1039 key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1); 1040 } 1041 } 1042 if (key.ao_key) { 1043 struct tcp_ao_key *rnext_key; 1044 1045 key.traffic_key = snd_other_key(key.ao_key); 1046 key.sne = READ_ONCE(ao_info->snd_sne); 1047 rnext_key = READ_ONCE(ao_info->rnext_key); 1048 key.rcv_next = rnext_key->rcvid; 1049 key.type = TCP_KEY_AO; 1050 #else 1051 if (0) { 1052 #endif 1053 #ifdef CONFIG_TCP_MD5SIG 1054 } else if (static_branch_unlikely(&tcp_md5_needed.key)) { 1055 key.md5_key = tcp_twsk_md5_key(tcptw); 1056 if (key.md5_key) 1057 key.type = TCP_KEY_MD5; 1058 #endif 1059 } 1060 1061 tcp_v4_send_ack(sk, skb, 1062 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, 1063 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, 1064 tcp_tw_tsval(tcptw), 1065 tcptw->tw_ts_recent, 1066 tw->tw_bound_dev_if, &key, 1067 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0, 1068 tw->tw_tos, 1069 tw->tw_txhash); 1070 1071 inet_twsk_put(tw); 1072 } 1073 1074 static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, 1075 struct request_sock *req) 1076 { 1077 struct tcp_key key = {}; 1078 1079 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV 1080 * sk->sk_state == TCP_SYN_RECV -> for Fast Open. 1081 */ 1082 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 : 1083 tcp_sk(sk)->snd_nxt; 1084 1085 #ifdef CONFIG_TCP_AO 1086 if (static_branch_unlikely(&tcp_ao_needed.key) && 1087 tcp_rsk_used_ao(req)) { 1088 const union tcp_md5_addr *addr; 1089 const struct tcp_ao_hdr *aoh; 1090 int l3index; 1091 1092 /* Invalid TCP option size or twice included auth */ 1093 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) 1094 return; 1095 if (!aoh) 1096 return; 1097 1098 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 1099 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; 1100 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, 1101 aoh->rnext_keyid, -1); 1102 if (unlikely(!key.ao_key)) { 1103 /* Send ACK with any matching MKT for the peer */ 1104 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1); 1105 /* Matching key disappeared (user removed the key?) 1106 * let the handshake timeout. 1107 */ 1108 if (!key.ao_key) { 1109 net_info_ratelimited("TCP-AO key for (%pI4, %d)->(%pI4, %d) suddenly disappeared, won't ACK new connection\n", 1110 addr, 1111 ntohs(tcp_hdr(skb)->source), 1112 &ip_hdr(skb)->daddr, 1113 ntohs(tcp_hdr(skb)->dest)); 1114 return; 1115 } 1116 } 1117 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC); 1118 if (!key.traffic_key) 1119 return; 1120 1121 key.type = TCP_KEY_AO; 1122 key.rcv_next = aoh->keyid; 1123 tcp_v4_ao_calc_key_rsk(key.ao_key, key.traffic_key, req); 1124 #else 1125 if (0) { 1126 #endif 1127 #ifdef CONFIG_TCP_MD5SIG 1128 } else if (static_branch_unlikely(&tcp_md5_needed.key)) { 1129 const union tcp_md5_addr *addr; 1130 int l3index; 1131 1132 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 1133 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; 1134 key.md5_key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 1135 if (key.md5_key) 1136 key.type = TCP_KEY_MD5; 1137 #endif 1138 } 1139 1140 /* RFC 7323 2.3 1141 * The window field (SEG.WND) of every outgoing segment, with the 1142 * exception of <SYN> segments, MUST be right-shifted by 1143 * Rcv.Wind.Shift bits: 1144 */ 1145 tcp_v4_send_ack(sk, skb, seq, 1146 tcp_rsk(req)->rcv_nxt, 1147 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale, 1148 tcp_rsk_tsval(tcp_rsk(req)), 1149 READ_ONCE(req->ts_recent), 1150 0, &key, 1151 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, 1152 ip_hdr(skb)->tos, 1153 READ_ONCE(tcp_rsk(req)->txhash)); 1154 if (tcp_key_is_ao(&key)) 1155 kfree(key.traffic_key); 1156 } 1157 1158 /* 1159 * Send a SYN-ACK after having received a SYN. 1160 * This still operates on a request_sock only, not on a big 1161 * socket. 1162 */ 1163 static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, 1164 struct flowi *fl, 1165 struct request_sock *req, 1166 struct tcp_fastopen_cookie *foc, 1167 enum tcp_synack_type synack_type, 1168 struct sk_buff *syn_skb) 1169 { 1170 const struct inet_request_sock *ireq = inet_rsk(req); 1171 struct flowi4 fl4; 1172 int err = -1; 1173 struct sk_buff *skb; 1174 u8 tos; 1175 1176 /* First, grab a route. */ 1177 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL) 1178 return -1; 1179 1180 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb); 1181 1182 if (skb) { 1183 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); 1184 1185 tos = READ_ONCE(inet_sk(sk)->tos); 1186 1187 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)) 1188 tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) | 1189 (tos & INET_ECN_MASK); 1190 1191 if (!INET_ECN_is_capable(tos) && 1192 tcp_bpf_ca_needs_ecn((struct sock *)req)) 1193 tos |= INET_ECN_ECT_0; 1194 1195 rcu_read_lock(); 1196 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, 1197 ireq->ir_rmt_addr, 1198 rcu_dereference(ireq->ireq_opt), 1199 tos); 1200 rcu_read_unlock(); 1201 err = net_xmit_eval(err); 1202 } 1203 1204 return err; 1205 } 1206 1207 /* 1208 * IPv4 request_sock destructor. 1209 */ 1210 static void tcp_v4_reqsk_destructor(struct request_sock *req) 1211 { 1212 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1)); 1213 } 1214 1215 #ifdef CONFIG_TCP_MD5SIG 1216 /* 1217 * RFC2385 MD5 checksumming requires a mapping of 1218 * IP address->MD5 Key. 1219 * We need to maintain these in the sk structure. 1220 */ 1221 1222 DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ); 1223 EXPORT_SYMBOL(tcp_md5_needed); 1224 1225 static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new) 1226 { 1227 if (!old) 1228 return true; 1229 1230 /* l3index always overrides non-l3index */ 1231 if (old->l3index && new->l3index == 0) 1232 return false; 1233 if (old->l3index == 0 && new->l3index) 1234 return true; 1235 1236 return old->prefixlen < new->prefixlen; 1237 } 1238 1239 /* Find the Key structure for an address. */ 1240 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, 1241 const union tcp_md5_addr *addr, 1242 int family, bool any_l3index) 1243 { 1244 const struct tcp_sock *tp = tcp_sk(sk); 1245 struct tcp_md5sig_key *key; 1246 const struct tcp_md5sig_info *md5sig; 1247 __be32 mask; 1248 struct tcp_md5sig_key *best_match = NULL; 1249 bool match; 1250 1251 /* caller either holds rcu_read_lock() or socket lock */ 1252 md5sig = rcu_dereference_check(tp->md5sig_info, 1253 lockdep_sock_is_held(sk)); 1254 if (!md5sig) 1255 return NULL; 1256 1257 hlist_for_each_entry_rcu(key, &md5sig->head, node, 1258 lockdep_sock_is_held(sk)) { 1259 if (key->family != family) 1260 continue; 1261 if (!any_l3index && key->flags & TCP_MD5SIG_FLAG_IFINDEX && 1262 key->l3index != l3index) 1263 continue; 1264 if (family == AF_INET) { 1265 mask = inet_make_mask(key->prefixlen); 1266 match = (key->addr.a4.s_addr & mask) == 1267 (addr->a4.s_addr & mask); 1268 #if IS_ENABLED(CONFIG_IPV6) 1269 } else if (family == AF_INET6) { 1270 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6, 1271 key->prefixlen); 1272 #endif 1273 } else { 1274 match = false; 1275 } 1276 1277 if (match && better_md5_match(best_match, key)) 1278 best_match = key; 1279 } 1280 return best_match; 1281 } 1282 EXPORT_SYMBOL(__tcp_md5_do_lookup); 1283 1284 static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk, 1285 const union tcp_md5_addr *addr, 1286 int family, u8 prefixlen, 1287 int l3index, u8 flags) 1288 { 1289 const struct tcp_sock *tp = tcp_sk(sk); 1290 struct tcp_md5sig_key *key; 1291 unsigned int size = sizeof(struct in_addr); 1292 const struct tcp_md5sig_info *md5sig; 1293 1294 /* caller either holds rcu_read_lock() or socket lock */ 1295 md5sig = rcu_dereference_check(tp->md5sig_info, 1296 lockdep_sock_is_held(sk)); 1297 if (!md5sig) 1298 return NULL; 1299 #if IS_ENABLED(CONFIG_IPV6) 1300 if (family == AF_INET6) 1301 size = sizeof(struct in6_addr); 1302 #endif 1303 hlist_for_each_entry_rcu(key, &md5sig->head, node, 1304 lockdep_sock_is_held(sk)) { 1305 if (key->family != family) 1306 continue; 1307 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX)) 1308 continue; 1309 if (key->l3index != l3index) 1310 continue; 1311 if (!memcmp(&key->addr, addr, size) && 1312 key->prefixlen == prefixlen) 1313 return key; 1314 } 1315 return NULL; 1316 } 1317 1318 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 1319 const struct sock *addr_sk) 1320 { 1321 const union tcp_md5_addr *addr; 1322 int l3index; 1323 1324 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), 1325 addr_sk->sk_bound_dev_if); 1326 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr; 1327 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 1328 } 1329 EXPORT_SYMBOL(tcp_v4_md5_lookup); 1330 1331 static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp) 1332 { 1333 struct tcp_sock *tp = tcp_sk(sk); 1334 struct tcp_md5sig_info *md5sig; 1335 1336 md5sig = kmalloc(sizeof(*md5sig), gfp); 1337 if (!md5sig) 1338 return -ENOMEM; 1339 1340 sk_gso_disable(sk); 1341 INIT_HLIST_HEAD(&md5sig->head); 1342 rcu_assign_pointer(tp->md5sig_info, md5sig); 1343 return 0; 1344 } 1345 1346 /* This can be called on a newly created socket, from other files */ 1347 static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1348 int family, u8 prefixlen, int l3index, u8 flags, 1349 const u8 *newkey, u8 newkeylen, gfp_t gfp) 1350 { 1351 /* Add Key to the list */ 1352 struct tcp_md5sig_key *key; 1353 struct tcp_sock *tp = tcp_sk(sk); 1354 struct tcp_md5sig_info *md5sig; 1355 1356 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags); 1357 if (key) { 1358 /* Pre-existing entry - just update that one. 1359 * Note that the key might be used concurrently. 1360 * data_race() is telling kcsan that we do not care of 1361 * key mismatches, since changing MD5 key on live flows 1362 * can lead to packet drops. 1363 */ 1364 data_race(memcpy(key->key, newkey, newkeylen)); 1365 1366 /* Pairs with READ_ONCE() in tcp_md5_hash_key(). 1367 * Also note that a reader could catch new key->keylen value 1368 * but old key->key[], this is the reason we use __GFP_ZERO 1369 * at sock_kmalloc() time below these lines. 1370 */ 1371 WRITE_ONCE(key->keylen, newkeylen); 1372 1373 return 0; 1374 } 1375 1376 md5sig = rcu_dereference_protected(tp->md5sig_info, 1377 lockdep_sock_is_held(sk)); 1378 1379 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO); 1380 if (!key) 1381 return -ENOMEM; 1382 1383 memcpy(key->key, newkey, newkeylen); 1384 key->keylen = newkeylen; 1385 key->family = family; 1386 key->prefixlen = prefixlen; 1387 key->l3index = l3index; 1388 key->flags = flags; 1389 memcpy(&key->addr, addr, 1390 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) : 1391 sizeof(struct in_addr)); 1392 hlist_add_head_rcu(&key->node, &md5sig->head); 1393 return 0; 1394 } 1395 1396 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 1397 int family, u8 prefixlen, int l3index, u8 flags, 1398 const u8 *newkey, u8 newkeylen) 1399 { 1400 struct tcp_sock *tp = tcp_sk(sk); 1401 1402 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) { 1403 if (tcp_md5_alloc_sigpool()) 1404 return -ENOMEM; 1405 1406 if (tcp_md5sig_info_add(sk, GFP_KERNEL)) { 1407 tcp_md5_release_sigpool(); 1408 return -ENOMEM; 1409 } 1410 1411 if (!static_branch_inc(&tcp_md5_needed.key)) { 1412 struct tcp_md5sig_info *md5sig; 1413 1414 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk)); 1415 rcu_assign_pointer(tp->md5sig_info, NULL); 1416 kfree_rcu(md5sig, rcu); 1417 tcp_md5_release_sigpool(); 1418 return -EUSERS; 1419 } 1420 } 1421 1422 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags, 1423 newkey, newkeylen, GFP_KERNEL); 1424 } 1425 EXPORT_SYMBOL(tcp_md5_do_add); 1426 1427 int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, 1428 int family, u8 prefixlen, int l3index, 1429 struct tcp_md5sig_key *key) 1430 { 1431 struct tcp_sock *tp = tcp_sk(sk); 1432 1433 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) { 1434 tcp_md5_add_sigpool(); 1435 1436 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) { 1437 tcp_md5_release_sigpool(); 1438 return -ENOMEM; 1439 } 1440 1441 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) { 1442 struct tcp_md5sig_info *md5sig; 1443 1444 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk)); 1445 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n"); 1446 rcu_assign_pointer(tp->md5sig_info, NULL); 1447 kfree_rcu(md5sig, rcu); 1448 tcp_md5_release_sigpool(); 1449 return -EUSERS; 1450 } 1451 } 1452 1453 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, 1454 key->flags, key->key, key->keylen, 1455 sk_gfp_mask(sk, GFP_ATOMIC)); 1456 } 1457 EXPORT_SYMBOL(tcp_md5_key_copy); 1458 1459 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family, 1460 u8 prefixlen, int l3index, u8 flags) 1461 { 1462 struct tcp_md5sig_key *key; 1463 1464 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags); 1465 if (!key) 1466 return -ENOENT; 1467 hlist_del_rcu(&key->node); 1468 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 1469 kfree_rcu(key, rcu); 1470 return 0; 1471 } 1472 EXPORT_SYMBOL(tcp_md5_do_del); 1473 1474 void tcp_clear_md5_list(struct sock *sk) 1475 { 1476 struct tcp_sock *tp = tcp_sk(sk); 1477 struct tcp_md5sig_key *key; 1478 struct hlist_node *n; 1479 struct tcp_md5sig_info *md5sig; 1480 1481 md5sig = rcu_dereference_protected(tp->md5sig_info, 1); 1482 1483 hlist_for_each_entry_safe(key, n, &md5sig->head, node) { 1484 hlist_del_rcu(&key->node); 1485 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 1486 kfree_rcu(key, rcu); 1487 } 1488 } 1489 1490 static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, 1491 sockptr_t optval, int optlen) 1492 { 1493 struct tcp_md5sig cmd; 1494 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr; 1495 const union tcp_md5_addr *addr; 1496 u8 prefixlen = 32; 1497 int l3index = 0; 1498 bool l3flag; 1499 u8 flags; 1500 1501 if (optlen < sizeof(cmd)) 1502 return -EINVAL; 1503 1504 if (copy_from_sockptr(&cmd, optval, sizeof(cmd))) 1505 return -EFAULT; 1506 1507 if (sin->sin_family != AF_INET) 1508 return -EINVAL; 1509 1510 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX; 1511 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX; 1512 1513 if (optname == TCP_MD5SIG_EXT && 1514 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) { 1515 prefixlen = cmd.tcpm_prefixlen; 1516 if (prefixlen > 32) 1517 return -EINVAL; 1518 } 1519 1520 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex && 1521 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) { 1522 struct net_device *dev; 1523 1524 rcu_read_lock(); 1525 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex); 1526 if (dev && netif_is_l3_master(dev)) 1527 l3index = dev->ifindex; 1528 1529 rcu_read_unlock(); 1530 1531 /* ok to reference set/not set outside of rcu; 1532 * right now device MUST be an L3 master 1533 */ 1534 if (!dev || !l3index) 1535 return -EINVAL; 1536 } 1537 1538 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr; 1539 1540 if (!cmd.tcpm_keylen) 1541 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags); 1542 1543 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) 1544 return -EINVAL; 1545 1546 /* Don't allow keys for peers that have a matching TCP-AO key. 1547 * See the comment in tcp_ao_add_cmd() 1548 */ 1549 if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false)) 1550 return -EKEYREJECTED; 1551 1552 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags, 1553 cmd.tcpm_key, cmd.tcpm_keylen); 1554 } 1555 1556 static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp, 1557 __be32 daddr, __be32 saddr, 1558 const struct tcphdr *th, int nbytes) 1559 { 1560 struct tcp4_pseudohdr *bp; 1561 struct scatterlist sg; 1562 struct tcphdr *_th; 1563 1564 bp = hp->scratch; 1565 bp->saddr = saddr; 1566 bp->daddr = daddr; 1567 bp->pad = 0; 1568 bp->protocol = IPPROTO_TCP; 1569 bp->len = cpu_to_be16(nbytes); 1570 1571 _th = (struct tcphdr *)(bp + 1); 1572 memcpy(_th, th, sizeof(*th)); 1573 _th->check = 0; 1574 1575 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th)); 1576 ahash_request_set_crypt(hp->req, &sg, NULL, 1577 sizeof(*bp) + sizeof(*th)); 1578 return crypto_ahash_update(hp->req); 1579 } 1580 1581 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 1582 __be32 daddr, __be32 saddr, const struct tcphdr *th) 1583 { 1584 struct tcp_sigpool hp; 1585 1586 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp)) 1587 goto clear_hash_nostart; 1588 1589 if (crypto_ahash_init(hp.req)) 1590 goto clear_hash; 1591 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2)) 1592 goto clear_hash; 1593 if (tcp_md5_hash_key(&hp, key)) 1594 goto clear_hash; 1595 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0); 1596 if (crypto_ahash_final(hp.req)) 1597 goto clear_hash; 1598 1599 tcp_sigpool_end(&hp); 1600 return 0; 1601 1602 clear_hash: 1603 tcp_sigpool_end(&hp); 1604 clear_hash_nostart: 1605 memset(md5_hash, 0, 16); 1606 return 1; 1607 } 1608 1609 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1610 const struct sock *sk, 1611 const struct sk_buff *skb) 1612 { 1613 const struct tcphdr *th = tcp_hdr(skb); 1614 struct tcp_sigpool hp; 1615 __be32 saddr, daddr; 1616 1617 if (sk) { /* valid for establish/request sockets */ 1618 saddr = sk->sk_rcv_saddr; 1619 daddr = sk->sk_daddr; 1620 } else { 1621 const struct iphdr *iph = ip_hdr(skb); 1622 saddr = iph->saddr; 1623 daddr = iph->daddr; 1624 } 1625 1626 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp)) 1627 goto clear_hash_nostart; 1628 1629 if (crypto_ahash_init(hp.req)) 1630 goto clear_hash; 1631 1632 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len)) 1633 goto clear_hash; 1634 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2)) 1635 goto clear_hash; 1636 if (tcp_md5_hash_key(&hp, key)) 1637 goto clear_hash; 1638 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0); 1639 if (crypto_ahash_final(hp.req)) 1640 goto clear_hash; 1641 1642 tcp_sigpool_end(&hp); 1643 return 0; 1644 1645 clear_hash: 1646 tcp_sigpool_end(&hp); 1647 clear_hash_nostart: 1648 memset(md5_hash, 0, 16); 1649 return 1; 1650 } 1651 EXPORT_SYMBOL(tcp_v4_md5_hash_skb); 1652 1653 #endif 1654 1655 static void tcp_v4_init_req(struct request_sock *req, 1656 const struct sock *sk_listener, 1657 struct sk_buff *skb) 1658 { 1659 struct inet_request_sock *ireq = inet_rsk(req); 1660 struct net *net = sock_net(sk_listener); 1661 1662 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr); 1663 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr); 1664 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb)); 1665 } 1666 1667 static struct dst_entry *tcp_v4_route_req(const struct sock *sk, 1668 struct sk_buff *skb, 1669 struct flowi *fl, 1670 struct request_sock *req) 1671 { 1672 tcp_v4_init_req(req, sk, skb); 1673 1674 if (security_inet_conn_request(sk, skb, req)) 1675 return NULL; 1676 1677 return inet_csk_route_req(sk, &fl->u.ip4, req); 1678 } 1679 1680 struct request_sock_ops tcp_request_sock_ops __read_mostly = { 1681 .family = PF_INET, 1682 .obj_size = sizeof(struct tcp_request_sock), 1683 .rtx_syn_ack = tcp_rtx_synack, 1684 .send_ack = tcp_v4_reqsk_send_ack, 1685 .destructor = tcp_v4_reqsk_destructor, 1686 .send_reset = tcp_v4_send_reset, 1687 .syn_ack_timeout = tcp_syn_ack_timeout, 1688 }; 1689 1690 const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { 1691 .mss_clamp = TCP_MSS_DEFAULT, 1692 #ifdef CONFIG_TCP_MD5SIG 1693 .req_md5_lookup = tcp_v4_md5_lookup, 1694 .calc_md5_hash = tcp_v4_md5_hash_skb, 1695 #endif 1696 #ifdef CONFIG_TCP_AO 1697 .ao_lookup = tcp_v4_ao_lookup_rsk, 1698 .ao_calc_key = tcp_v4_ao_calc_key_rsk, 1699 .ao_synack_hash = tcp_v4_ao_synack_hash, 1700 #endif 1701 #ifdef CONFIG_SYN_COOKIES 1702 .cookie_init_seq = cookie_v4_init_sequence, 1703 #endif 1704 .route_req = tcp_v4_route_req, 1705 .init_seq = tcp_v4_init_seq, 1706 .init_ts_off = tcp_v4_init_ts_off, 1707 .send_synack = tcp_v4_send_synack, 1708 }; 1709 1710 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) 1711 { 1712 /* Never answer to SYNs send to broadcast or multicast */ 1713 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) 1714 goto drop; 1715 1716 return tcp_conn_request(&tcp_request_sock_ops, 1717 &tcp_request_sock_ipv4_ops, sk, skb); 1718 1719 drop: 1720 tcp_listendrop(sk); 1721 return 0; 1722 } 1723 EXPORT_SYMBOL(tcp_v4_conn_request); 1724 1725 1726 /* 1727 * The three way handshake has completed - we got a valid synack - 1728 * now create the new socket. 1729 */ 1730 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 1731 struct request_sock *req, 1732 struct dst_entry *dst, 1733 struct request_sock *req_unhash, 1734 bool *own_req) 1735 { 1736 struct inet_request_sock *ireq; 1737 bool found_dup_sk = false; 1738 struct inet_sock *newinet; 1739 struct tcp_sock *newtp; 1740 struct sock *newsk; 1741 #ifdef CONFIG_TCP_MD5SIG 1742 const union tcp_md5_addr *addr; 1743 struct tcp_md5sig_key *key; 1744 int l3index; 1745 #endif 1746 struct ip_options_rcu *inet_opt; 1747 1748 if (sk_acceptq_is_full(sk)) 1749 goto exit_overflow; 1750 1751 newsk = tcp_create_openreq_child(sk, req, skb); 1752 if (!newsk) 1753 goto exit_nonewsk; 1754 1755 newsk->sk_gso_type = SKB_GSO_TCPV4; 1756 inet_sk_rx_dst_set(newsk, skb); 1757 1758 newtp = tcp_sk(newsk); 1759 newinet = inet_sk(newsk); 1760 ireq = inet_rsk(req); 1761 sk_daddr_set(newsk, ireq->ir_rmt_addr); 1762 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr); 1763 newsk->sk_bound_dev_if = ireq->ir_iif; 1764 newinet->inet_saddr = ireq->ir_loc_addr; 1765 inet_opt = rcu_dereference(ireq->ireq_opt); 1766 RCU_INIT_POINTER(newinet->inet_opt, inet_opt); 1767 newinet->mc_index = inet_iif(skb); 1768 newinet->mc_ttl = ip_hdr(skb)->ttl; 1769 newinet->rcv_tos = ip_hdr(skb)->tos; 1770 inet_csk(newsk)->icsk_ext_hdr_len = 0; 1771 if (inet_opt) 1772 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; 1773 atomic_set(&newinet->inet_id, get_random_u16()); 1774 1775 /* Set ToS of the new socket based upon the value of incoming SYN. 1776 * ECT bits are set later in tcp_init_transfer(). 1777 */ 1778 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)) 1779 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK; 1780 1781 if (!dst) { 1782 dst = inet_csk_route_child_sock(sk, newsk, req); 1783 if (!dst) 1784 goto put_and_exit; 1785 } else { 1786 /* syncookie case : see end of cookie_v4_check() */ 1787 } 1788 sk_setup_caps(newsk, dst); 1789 1790 tcp_ca_openreq_child(newsk, dst); 1791 1792 tcp_sync_mss(newsk, dst_mtu(dst)); 1793 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst)); 1794 1795 tcp_initialize_rcv_mss(newsk); 1796 1797 #ifdef CONFIG_TCP_MD5SIG 1798 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif); 1799 /* Copy over the MD5 key from the original socket */ 1800 addr = (union tcp_md5_addr *)&newinet->inet_daddr; 1801 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); 1802 if (key && !tcp_rsk_used_ao(req)) { 1803 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key)) 1804 goto put_and_exit; 1805 sk_gso_disable(newsk); 1806 } 1807 #endif 1808 #ifdef CONFIG_TCP_AO 1809 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET)) 1810 goto put_and_exit; /* OOM, release back memory */ 1811 #endif 1812 1813 if (__inet_inherit_port(sk, newsk) < 0) 1814 goto put_and_exit; 1815 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), 1816 &found_dup_sk); 1817 if (likely(*own_req)) { 1818 tcp_move_syn(newtp, req); 1819 ireq->ireq_opt = NULL; 1820 } else { 1821 newinet->inet_opt = NULL; 1822 1823 if (!req_unhash && found_dup_sk) { 1824 /* This code path should only be executed in the 1825 * syncookie case only 1826 */ 1827 bh_unlock_sock(newsk); 1828 sock_put(newsk); 1829 newsk = NULL; 1830 } 1831 } 1832 return newsk; 1833 1834 exit_overflow: 1835 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 1836 exit_nonewsk: 1837 dst_release(dst); 1838 exit: 1839 tcp_listendrop(sk); 1840 return NULL; 1841 put_and_exit: 1842 newinet->inet_opt = NULL; 1843 inet_csk_prepare_forced_close(newsk); 1844 tcp_done(newsk); 1845 goto exit; 1846 } 1847 EXPORT_SYMBOL(tcp_v4_syn_recv_sock); 1848 1849 static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb) 1850 { 1851 #ifdef CONFIG_SYN_COOKIES 1852 const struct tcphdr *th = tcp_hdr(skb); 1853 1854 if (!th->syn) 1855 sk = cookie_v4_check(sk, skb); 1856 #endif 1857 return sk; 1858 } 1859 1860 u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, 1861 struct tcphdr *th, u32 *cookie) 1862 { 1863 u16 mss = 0; 1864 #ifdef CONFIG_SYN_COOKIES 1865 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops, 1866 &tcp_request_sock_ipv4_ops, sk, th); 1867 if (mss) { 1868 *cookie = __cookie_v4_init_sequence(iph, th, &mss); 1869 tcp_synq_overflow(sk); 1870 } 1871 #endif 1872 return mss; 1873 } 1874 1875 INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *, 1876 u32)); 1877 /* The socket must have it's spinlock held when we get 1878 * here, unless it is a TCP_LISTEN socket. 1879 * 1880 * We have a potential double-lock case here, so even when 1881 * doing backlog processing we use the BH locking scheme. 1882 * This is because we cannot sleep with the original spinlock 1883 * held. 1884 */ 1885 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) 1886 { 1887 enum skb_drop_reason reason; 1888 struct sock *rsk; 1889 1890 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ 1891 struct dst_entry *dst; 1892 1893 dst = rcu_dereference_protected(sk->sk_rx_dst, 1894 lockdep_sock_is_held(sk)); 1895 1896 sock_rps_save_rxhash(sk, skb); 1897 sk_mark_napi_id(sk, skb); 1898 if (dst) { 1899 if (sk->sk_rx_dst_ifindex != skb->skb_iif || 1900 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check, 1901 dst, 0)) { 1902 RCU_INIT_POINTER(sk->sk_rx_dst, NULL); 1903 dst_release(dst); 1904 } 1905 } 1906 tcp_rcv_established(sk, skb); 1907 return 0; 1908 } 1909 1910 if (tcp_checksum_complete(skb)) 1911 goto csum_err; 1912 1913 if (sk->sk_state == TCP_LISTEN) { 1914 struct sock *nsk = tcp_v4_cookie_check(sk, skb); 1915 1916 if (!nsk) 1917 return 0; 1918 if (nsk != sk) { 1919 reason = tcp_child_process(sk, nsk, skb); 1920 if (reason) { 1921 rsk = nsk; 1922 goto reset; 1923 } 1924 return 0; 1925 } 1926 } else 1927 sock_rps_save_rxhash(sk, skb); 1928 1929 reason = tcp_rcv_state_process(sk, skb); 1930 if (reason) { 1931 rsk = sk; 1932 goto reset; 1933 } 1934 return 0; 1935 1936 reset: 1937 tcp_v4_send_reset(rsk, skb); 1938 discard: 1939 kfree_skb_reason(skb, reason); 1940 /* Be careful here. If this function gets more complicated and 1941 * gcc suffers from register pressure on the x86, sk (in %ebx) 1942 * might be destroyed here. This current version compiles correctly, 1943 * but you have been warned. 1944 */ 1945 return 0; 1946 1947 csum_err: 1948 reason = SKB_DROP_REASON_TCP_CSUM; 1949 trace_tcp_bad_csum(skb); 1950 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); 1951 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); 1952 goto discard; 1953 } 1954 EXPORT_SYMBOL(tcp_v4_do_rcv); 1955 1956 int tcp_v4_early_demux(struct sk_buff *skb) 1957 { 1958 struct net *net = dev_net(skb->dev); 1959 const struct iphdr *iph; 1960 const struct tcphdr *th; 1961 struct sock *sk; 1962 1963 if (skb->pkt_type != PACKET_HOST) 1964 return 0; 1965 1966 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr))) 1967 return 0; 1968 1969 iph = ip_hdr(skb); 1970 th = tcp_hdr(skb); 1971 1972 if (th->doff < sizeof(struct tcphdr) / 4) 1973 return 0; 1974 1975 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, 1976 iph->saddr, th->source, 1977 iph->daddr, ntohs(th->dest), 1978 skb->skb_iif, inet_sdif(skb)); 1979 if (sk) { 1980 skb->sk = sk; 1981 skb->destructor = sock_edemux; 1982 if (sk_fullsock(sk)) { 1983 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst); 1984 1985 if (dst) 1986 dst = dst_check(dst, 0); 1987 if (dst && 1988 sk->sk_rx_dst_ifindex == skb->skb_iif) 1989 skb_dst_set_noref(skb, dst); 1990 } 1991 } 1992 return 0; 1993 } 1994 1995 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, 1996 enum skb_drop_reason *reason) 1997 { 1998 u32 limit, tail_gso_size, tail_gso_segs; 1999 struct skb_shared_info *shinfo; 2000 const struct tcphdr *th; 2001 struct tcphdr *thtail; 2002 struct sk_buff *tail; 2003 unsigned int hdrlen; 2004 bool fragstolen; 2005 u32 gso_segs; 2006 u32 gso_size; 2007 int delta; 2008 2009 /* In case all data was pulled from skb frags (in __pskb_pull_tail()), 2010 * we can fix skb->truesize to its real value to avoid future drops. 2011 * This is valid because skb is not yet charged to the socket. 2012 * It has been noticed pure SACK packets were sometimes dropped 2013 * (if cooked by drivers without copybreak feature). 2014 */ 2015 skb_condense(skb); 2016 2017 skb_dst_drop(skb); 2018 2019 if (unlikely(tcp_checksum_complete(skb))) { 2020 bh_unlock_sock(sk); 2021 trace_tcp_bad_csum(skb); 2022 *reason = SKB_DROP_REASON_TCP_CSUM; 2023 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); 2024 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); 2025 return true; 2026 } 2027 2028 /* Attempt coalescing to last skb in backlog, even if we are 2029 * above the limits. 2030 * This is okay because skb capacity is limited to MAX_SKB_FRAGS. 2031 */ 2032 th = (const struct tcphdr *)skb->data; 2033 hdrlen = th->doff * 4; 2034 2035 tail = sk->sk_backlog.tail; 2036 if (!tail) 2037 goto no_coalesce; 2038 thtail = (struct tcphdr *)tail->data; 2039 2040 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq || 2041 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield || 2042 ((TCP_SKB_CB(tail)->tcp_flags | 2043 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) || 2044 !((TCP_SKB_CB(tail)->tcp_flags & 2045 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) || 2046 ((TCP_SKB_CB(tail)->tcp_flags ^ 2047 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) || 2048 #ifdef CONFIG_TLS_DEVICE 2049 tail->decrypted != skb->decrypted || 2050 #endif 2051 !mptcp_skb_can_collapse(tail, skb) || 2052 thtail->doff != th->doff || 2053 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th))) 2054 goto no_coalesce; 2055 2056 __skb_pull(skb, hdrlen); 2057 2058 shinfo = skb_shinfo(skb); 2059 gso_size = shinfo->gso_size ?: skb->len; 2060 gso_segs = shinfo->gso_segs ?: 1; 2061 2062 shinfo = skb_shinfo(tail); 2063 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen); 2064 tail_gso_segs = shinfo->gso_segs ?: 1; 2065 2066 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) { 2067 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq; 2068 2069 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) { 2070 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq; 2071 thtail->window = th->window; 2072 } 2073 2074 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and 2075 * thtail->fin, so that the fast path in tcp_rcv_established() 2076 * is not entered if we append a packet with a FIN. 2077 * SYN, RST, URG are not present. 2078 * ACK is set on both packets. 2079 * PSH : we do not really care in TCP stack, 2080 * at least for 'GRO' packets. 2081 */ 2082 thtail->fin |= th->fin; 2083 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags; 2084 2085 if (TCP_SKB_CB(skb)->has_rxtstamp) { 2086 TCP_SKB_CB(tail)->has_rxtstamp = true; 2087 tail->tstamp = skb->tstamp; 2088 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp; 2089 } 2090 2091 /* Not as strict as GRO. We only need to carry mss max value */ 2092 shinfo->gso_size = max(gso_size, tail_gso_size); 2093 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF); 2094 2095 sk->sk_backlog.len += delta; 2096 __NET_INC_STATS(sock_net(sk), 2097 LINUX_MIB_TCPBACKLOGCOALESCE); 2098 kfree_skb_partial(skb, fragstolen); 2099 return false; 2100 } 2101 __skb_push(skb, hdrlen); 2102 2103 no_coalesce: 2104 limit = (u32)READ_ONCE(sk->sk_rcvbuf) + (u32)(READ_ONCE(sk->sk_sndbuf) >> 1); 2105 2106 /* Only socket owner can try to collapse/prune rx queues 2107 * to reduce memory overhead, so add a little headroom here. 2108 * Few sockets backlog are possibly concurrently non empty. 2109 */ 2110 limit += 64 * 1024; 2111 2112 if (unlikely(sk_add_backlog(sk, skb, limit))) { 2113 bh_unlock_sock(sk); 2114 *reason = SKB_DROP_REASON_SOCKET_BACKLOG; 2115 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP); 2116 return true; 2117 } 2118 return false; 2119 } 2120 EXPORT_SYMBOL(tcp_add_backlog); 2121 2122 int tcp_filter(struct sock *sk, struct sk_buff *skb) 2123 { 2124 struct tcphdr *th = (struct tcphdr *)skb->data; 2125 2126 return sk_filter_trim_cap(sk, skb, th->doff * 4); 2127 } 2128 EXPORT_SYMBOL(tcp_filter); 2129 2130 static void tcp_v4_restore_cb(struct sk_buff *skb) 2131 { 2132 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4, 2133 sizeof(struct inet_skb_parm)); 2134 } 2135 2136 static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph, 2137 const struct tcphdr *th) 2138 { 2139 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB() 2140 * barrier() makes sure compiler wont play fool^Waliasing games. 2141 */ 2142 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb), 2143 sizeof(struct inet_skb_parm)); 2144 barrier(); 2145 2146 TCP_SKB_CB(skb)->seq = ntohl(th->seq); 2147 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + 2148 skb->len - th->doff * 4); 2149 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); 2150 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th); 2151 TCP_SKB_CB(skb)->tcp_tw_isn = 0; 2152 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph); 2153 TCP_SKB_CB(skb)->sacked = 0; 2154 TCP_SKB_CB(skb)->has_rxtstamp = 2155 skb->tstamp || skb_hwtstamps(skb)->hwtstamp; 2156 } 2157 2158 /* 2159 * From tcp_input.c 2160 */ 2161 2162 int tcp_v4_rcv(struct sk_buff *skb) 2163 { 2164 struct net *net = dev_net(skb->dev); 2165 enum skb_drop_reason drop_reason; 2166 int sdif = inet_sdif(skb); 2167 int dif = inet_iif(skb); 2168 const struct iphdr *iph; 2169 const struct tcphdr *th; 2170 bool refcounted; 2171 struct sock *sk; 2172 int ret; 2173 2174 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; 2175 if (skb->pkt_type != PACKET_HOST) 2176 goto discard_it; 2177 2178 /* Count it even if it's bad */ 2179 __TCP_INC_STATS(net, TCP_MIB_INSEGS); 2180 2181 if (!pskb_may_pull(skb, sizeof(struct tcphdr))) 2182 goto discard_it; 2183 2184 th = (const struct tcphdr *)skb->data; 2185 2186 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) { 2187 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL; 2188 goto bad_packet; 2189 } 2190 if (!pskb_may_pull(skb, th->doff * 4)) 2191 goto discard_it; 2192 2193 /* An explanation is required here, I think. 2194 * Packet length and doff are validated by header prediction, 2195 * provided case of th->doff==0 is eliminated. 2196 * So, we defer the checks. */ 2197 2198 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo)) 2199 goto csum_error; 2200 2201 th = (const struct tcphdr *)skb->data; 2202 iph = ip_hdr(skb); 2203 lookup: 2204 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo, 2205 skb, __tcp_hdrlen(th), th->source, 2206 th->dest, sdif, &refcounted); 2207 if (!sk) 2208 goto no_tcp_socket; 2209 2210 process: 2211 if (sk->sk_state == TCP_TIME_WAIT) 2212 goto do_time_wait; 2213 2214 if (sk->sk_state == TCP_NEW_SYN_RECV) { 2215 struct request_sock *req = inet_reqsk(sk); 2216 bool req_stolen = false; 2217 struct sock *nsk; 2218 2219 sk = req->rsk_listener; 2220 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 2221 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 2222 else 2223 drop_reason = tcp_inbound_hash(sk, req, skb, 2224 &iph->saddr, &iph->daddr, 2225 AF_INET, dif, sdif); 2226 if (unlikely(drop_reason)) { 2227 sk_drops_add(sk, skb); 2228 reqsk_put(req); 2229 goto discard_it; 2230 } 2231 if (tcp_checksum_complete(skb)) { 2232 reqsk_put(req); 2233 goto csum_error; 2234 } 2235 if (unlikely(sk->sk_state != TCP_LISTEN)) { 2236 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb); 2237 if (!nsk) { 2238 inet_csk_reqsk_queue_drop_and_put(sk, req); 2239 goto lookup; 2240 } 2241 sk = nsk; 2242 /* reuseport_migrate_sock() has already held one sk_refcnt 2243 * before returning. 2244 */ 2245 } else { 2246 /* We own a reference on the listener, increase it again 2247 * as we might lose it too soon. 2248 */ 2249 sock_hold(sk); 2250 } 2251 refcounted = true; 2252 nsk = NULL; 2253 if (!tcp_filter(sk, skb)) { 2254 th = (const struct tcphdr *)skb->data; 2255 iph = ip_hdr(skb); 2256 tcp_v4_fill_cb(skb, iph, th); 2257 nsk = tcp_check_req(sk, skb, req, false, &req_stolen); 2258 } else { 2259 drop_reason = SKB_DROP_REASON_SOCKET_FILTER; 2260 } 2261 if (!nsk) { 2262 reqsk_put(req); 2263 if (req_stolen) { 2264 /* Another cpu got exclusive access to req 2265 * and created a full blown socket. 2266 * Try to feed this packet to this socket 2267 * instead of discarding it. 2268 */ 2269 tcp_v4_restore_cb(skb); 2270 sock_put(sk); 2271 goto lookup; 2272 } 2273 goto discard_and_relse; 2274 } 2275 nf_reset_ct(skb); 2276 if (nsk == sk) { 2277 reqsk_put(req); 2278 tcp_v4_restore_cb(skb); 2279 } else { 2280 drop_reason = tcp_child_process(sk, nsk, skb); 2281 if (drop_reason) { 2282 tcp_v4_send_reset(nsk, skb); 2283 goto discard_and_relse; 2284 } 2285 sock_put(sk); 2286 return 0; 2287 } 2288 } 2289 2290 if (static_branch_unlikely(&ip4_min_ttl)) { 2291 /* min_ttl can be changed concurrently from do_ip_setsockopt() */ 2292 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) { 2293 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); 2294 drop_reason = SKB_DROP_REASON_TCP_MINTTL; 2295 goto discard_and_relse; 2296 } 2297 } 2298 2299 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) { 2300 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 2301 goto discard_and_relse; 2302 } 2303 2304 drop_reason = tcp_inbound_hash(sk, NULL, skb, &iph->saddr, &iph->daddr, 2305 AF_INET, dif, sdif); 2306 if (drop_reason) 2307 goto discard_and_relse; 2308 2309 nf_reset_ct(skb); 2310 2311 if (tcp_filter(sk, skb)) { 2312 drop_reason = SKB_DROP_REASON_SOCKET_FILTER; 2313 goto discard_and_relse; 2314 } 2315 th = (const struct tcphdr *)skb->data; 2316 iph = ip_hdr(skb); 2317 tcp_v4_fill_cb(skb, iph, th); 2318 2319 skb->dev = NULL; 2320 2321 if (sk->sk_state == TCP_LISTEN) { 2322 ret = tcp_v4_do_rcv(sk, skb); 2323 goto put_and_return; 2324 } 2325 2326 sk_incoming_cpu_update(sk); 2327 2328 bh_lock_sock_nested(sk); 2329 tcp_segs_in(tcp_sk(sk), skb); 2330 ret = 0; 2331 if (!sock_owned_by_user(sk)) { 2332 ret = tcp_v4_do_rcv(sk, skb); 2333 } else { 2334 if (tcp_add_backlog(sk, skb, &drop_reason)) 2335 goto discard_and_relse; 2336 } 2337 bh_unlock_sock(sk); 2338 2339 put_and_return: 2340 if (refcounted) 2341 sock_put(sk); 2342 2343 return ret; 2344 2345 no_tcp_socket: 2346 drop_reason = SKB_DROP_REASON_NO_SOCKET; 2347 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 2348 goto discard_it; 2349 2350 tcp_v4_fill_cb(skb, iph, th); 2351 2352 if (tcp_checksum_complete(skb)) { 2353 csum_error: 2354 drop_reason = SKB_DROP_REASON_TCP_CSUM; 2355 trace_tcp_bad_csum(skb); 2356 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS); 2357 bad_packet: 2358 __TCP_INC_STATS(net, TCP_MIB_INERRS); 2359 } else { 2360 tcp_v4_send_reset(NULL, skb); 2361 } 2362 2363 discard_it: 2364 SKB_DR_OR(drop_reason, NOT_SPECIFIED); 2365 /* Discard frame. */ 2366 kfree_skb_reason(skb, drop_reason); 2367 return 0; 2368 2369 discard_and_relse: 2370 sk_drops_add(sk, skb); 2371 if (refcounted) 2372 sock_put(sk); 2373 goto discard_it; 2374 2375 do_time_wait: 2376 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 2377 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 2378 inet_twsk_put(inet_twsk(sk)); 2379 goto discard_it; 2380 } 2381 2382 tcp_v4_fill_cb(skb, iph, th); 2383 2384 if (tcp_checksum_complete(skb)) { 2385 inet_twsk_put(inet_twsk(sk)); 2386 goto csum_error; 2387 } 2388 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) { 2389 case TCP_TW_SYN: { 2390 struct sock *sk2 = inet_lookup_listener(net, 2391 net->ipv4.tcp_death_row.hashinfo, 2392 skb, __tcp_hdrlen(th), 2393 iph->saddr, th->source, 2394 iph->daddr, th->dest, 2395 inet_iif(skb), 2396 sdif); 2397 if (sk2) { 2398 inet_twsk_deschedule_put(inet_twsk(sk)); 2399 sk = sk2; 2400 tcp_v4_restore_cb(skb); 2401 refcounted = false; 2402 goto process; 2403 } 2404 } 2405 /* to ACK */ 2406 fallthrough; 2407 case TCP_TW_ACK: 2408 tcp_v4_timewait_ack(sk, skb); 2409 break; 2410 case TCP_TW_RST: 2411 tcp_v4_send_reset(sk, skb); 2412 inet_twsk_deschedule_put(inet_twsk(sk)); 2413 goto discard_it; 2414 case TCP_TW_SUCCESS:; 2415 } 2416 goto discard_it; 2417 } 2418 2419 static struct timewait_sock_ops tcp_timewait_sock_ops = { 2420 .twsk_obj_size = sizeof(struct tcp_timewait_sock), 2421 .twsk_unique = tcp_twsk_unique, 2422 .twsk_destructor= tcp_twsk_destructor, 2423 }; 2424 2425 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) 2426 { 2427 struct dst_entry *dst = skb_dst(skb); 2428 2429 if (dst && dst_hold_safe(dst)) { 2430 rcu_assign_pointer(sk->sk_rx_dst, dst); 2431 sk->sk_rx_dst_ifindex = skb->skb_iif; 2432 } 2433 } 2434 EXPORT_SYMBOL(inet_sk_rx_dst_set); 2435 2436 const struct inet_connection_sock_af_ops ipv4_specific = { 2437 .queue_xmit = ip_queue_xmit, 2438 .send_check = tcp_v4_send_check, 2439 .rebuild_header = inet_sk_rebuild_header, 2440 .sk_rx_dst_set = inet_sk_rx_dst_set, 2441 .conn_request = tcp_v4_conn_request, 2442 .syn_recv_sock = tcp_v4_syn_recv_sock, 2443 .net_header_len = sizeof(struct iphdr), 2444 .setsockopt = ip_setsockopt, 2445 .getsockopt = ip_getsockopt, 2446 .addr2sockaddr = inet_csk_addr2sockaddr, 2447 .sockaddr_len = sizeof(struct sockaddr_in), 2448 .mtu_reduced = tcp_v4_mtu_reduced, 2449 }; 2450 EXPORT_SYMBOL(ipv4_specific); 2451 2452 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) 2453 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = { 2454 #ifdef CONFIG_TCP_MD5SIG 2455 .md5_lookup = tcp_v4_md5_lookup, 2456 .calc_md5_hash = tcp_v4_md5_hash_skb, 2457 .md5_parse = tcp_v4_parse_md5_keys, 2458 #endif 2459 #ifdef CONFIG_TCP_AO 2460 .ao_lookup = tcp_v4_ao_lookup, 2461 .calc_ao_hash = tcp_v4_ao_hash_skb, 2462 .ao_parse = tcp_v4_parse_ao, 2463 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk, 2464 #endif 2465 }; 2466 #endif 2467 2468 /* NOTE: A lot of things set to zero explicitly by call to 2469 * sk_alloc() so need not be done here. 2470 */ 2471 static int tcp_v4_init_sock(struct sock *sk) 2472 { 2473 struct inet_connection_sock *icsk = inet_csk(sk); 2474 2475 tcp_init_sock(sk); 2476 2477 icsk->icsk_af_ops = &ipv4_specific; 2478 2479 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) 2480 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific; 2481 #endif 2482 2483 return 0; 2484 } 2485 2486 #ifdef CONFIG_TCP_MD5SIG 2487 static void tcp_md5sig_info_free_rcu(struct rcu_head *head) 2488 { 2489 struct tcp_md5sig_info *md5sig; 2490 2491 md5sig = container_of(head, struct tcp_md5sig_info, rcu); 2492 kfree(md5sig); 2493 static_branch_slow_dec_deferred(&tcp_md5_needed); 2494 tcp_md5_release_sigpool(); 2495 } 2496 #endif 2497 2498 void tcp_v4_destroy_sock(struct sock *sk) 2499 { 2500 struct tcp_sock *tp = tcp_sk(sk); 2501 2502 trace_tcp_destroy_sock(sk); 2503 2504 tcp_clear_xmit_timers(sk); 2505 2506 tcp_cleanup_congestion_control(sk); 2507 2508 tcp_cleanup_ulp(sk); 2509 2510 /* Cleanup up the write buffer. */ 2511 tcp_write_queue_purge(sk); 2512 2513 /* Check if we want to disable active TFO */ 2514 tcp_fastopen_active_disable_ofo_check(sk); 2515 2516 /* Cleans up our, hopefully empty, out_of_order_queue. */ 2517 skb_rbtree_purge(&tp->out_of_order_queue); 2518 2519 #ifdef CONFIG_TCP_MD5SIG 2520 /* Clean up the MD5 key list, if any */ 2521 if (tp->md5sig_info) { 2522 struct tcp_md5sig_info *md5sig; 2523 2524 md5sig = rcu_dereference_protected(tp->md5sig_info, 1); 2525 tcp_clear_md5_list(sk); 2526 call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu); 2527 rcu_assign_pointer(tp->md5sig_info, NULL); 2528 } 2529 #endif 2530 tcp_ao_destroy_sock(sk, false); 2531 2532 /* Clean up a referenced TCP bind bucket. */ 2533 if (inet_csk(sk)->icsk_bind_hash) 2534 inet_put_port(sk); 2535 2536 BUG_ON(rcu_access_pointer(tp->fastopen_rsk)); 2537 2538 /* If socket is aborted during connect operation */ 2539 tcp_free_fastopen_req(tp); 2540 tcp_fastopen_destroy_cipher(sk); 2541 tcp_saved_syn_free(tp); 2542 2543 sk_sockets_allocated_dec(sk); 2544 } 2545 EXPORT_SYMBOL(tcp_v4_destroy_sock); 2546 2547 #ifdef CONFIG_PROC_FS 2548 /* Proc filesystem TCP sock list dumping. */ 2549 2550 static unsigned short seq_file_family(const struct seq_file *seq); 2551 2552 static bool seq_sk_match(struct seq_file *seq, const struct sock *sk) 2553 { 2554 unsigned short family = seq_file_family(seq); 2555 2556 /* AF_UNSPEC is used as a match all */ 2557 return ((family == AF_UNSPEC || family == sk->sk_family) && 2558 net_eq(sock_net(sk), seq_file_net(seq))); 2559 } 2560 2561 /* Find a non empty bucket (starting from st->bucket) 2562 * and return the first sk from it. 2563 */ 2564 static void *listening_get_first(struct seq_file *seq) 2565 { 2566 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2567 struct tcp_iter_state *st = seq->private; 2568 2569 st->offset = 0; 2570 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) { 2571 struct inet_listen_hashbucket *ilb2; 2572 struct hlist_nulls_node *node; 2573 struct sock *sk; 2574 2575 ilb2 = &hinfo->lhash2[st->bucket]; 2576 if (hlist_nulls_empty(&ilb2->nulls_head)) 2577 continue; 2578 2579 spin_lock(&ilb2->lock); 2580 sk_nulls_for_each(sk, node, &ilb2->nulls_head) { 2581 if (seq_sk_match(seq, sk)) 2582 return sk; 2583 } 2584 spin_unlock(&ilb2->lock); 2585 } 2586 2587 return NULL; 2588 } 2589 2590 /* Find the next sk of "cur" within the same bucket (i.e. st->bucket). 2591 * If "cur" is the last one in the st->bucket, 2592 * call listening_get_first() to return the first sk of the next 2593 * non empty bucket. 2594 */ 2595 static void *listening_get_next(struct seq_file *seq, void *cur) 2596 { 2597 struct tcp_iter_state *st = seq->private; 2598 struct inet_listen_hashbucket *ilb2; 2599 struct hlist_nulls_node *node; 2600 struct inet_hashinfo *hinfo; 2601 struct sock *sk = cur; 2602 2603 ++st->num; 2604 ++st->offset; 2605 2606 sk = sk_nulls_next(sk); 2607 sk_nulls_for_each_from(sk, node) { 2608 if (seq_sk_match(seq, sk)) 2609 return sk; 2610 } 2611 2612 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2613 ilb2 = &hinfo->lhash2[st->bucket]; 2614 spin_unlock(&ilb2->lock); 2615 ++st->bucket; 2616 return listening_get_first(seq); 2617 } 2618 2619 static void *listening_get_idx(struct seq_file *seq, loff_t *pos) 2620 { 2621 struct tcp_iter_state *st = seq->private; 2622 void *rc; 2623 2624 st->bucket = 0; 2625 st->offset = 0; 2626 rc = listening_get_first(seq); 2627 2628 while (rc && *pos) { 2629 rc = listening_get_next(seq, rc); 2630 --*pos; 2631 } 2632 return rc; 2633 } 2634 2635 static inline bool empty_bucket(struct inet_hashinfo *hinfo, 2636 const struct tcp_iter_state *st) 2637 { 2638 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain); 2639 } 2640 2641 /* 2642 * Get first established socket starting from bucket given in st->bucket. 2643 * If st->bucket is zero, the very first socket in the hash is returned. 2644 */ 2645 static void *established_get_first(struct seq_file *seq) 2646 { 2647 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2648 struct tcp_iter_state *st = seq->private; 2649 2650 st->offset = 0; 2651 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) { 2652 struct sock *sk; 2653 struct hlist_nulls_node *node; 2654 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket); 2655 2656 cond_resched(); 2657 2658 /* Lockless fast path for the common case of empty buckets */ 2659 if (empty_bucket(hinfo, st)) 2660 continue; 2661 2662 spin_lock_bh(lock); 2663 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) { 2664 if (seq_sk_match(seq, sk)) 2665 return sk; 2666 } 2667 spin_unlock_bh(lock); 2668 } 2669 2670 return NULL; 2671 } 2672 2673 static void *established_get_next(struct seq_file *seq, void *cur) 2674 { 2675 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2676 struct tcp_iter_state *st = seq->private; 2677 struct hlist_nulls_node *node; 2678 struct sock *sk = cur; 2679 2680 ++st->num; 2681 ++st->offset; 2682 2683 sk = sk_nulls_next(sk); 2684 2685 sk_nulls_for_each_from(sk, node) { 2686 if (seq_sk_match(seq, sk)) 2687 return sk; 2688 } 2689 2690 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket)); 2691 ++st->bucket; 2692 return established_get_first(seq); 2693 } 2694 2695 static void *established_get_idx(struct seq_file *seq, loff_t pos) 2696 { 2697 struct tcp_iter_state *st = seq->private; 2698 void *rc; 2699 2700 st->bucket = 0; 2701 rc = established_get_first(seq); 2702 2703 while (rc && pos) { 2704 rc = established_get_next(seq, rc); 2705 --pos; 2706 } 2707 return rc; 2708 } 2709 2710 static void *tcp_get_idx(struct seq_file *seq, loff_t pos) 2711 { 2712 void *rc; 2713 struct tcp_iter_state *st = seq->private; 2714 2715 st->state = TCP_SEQ_STATE_LISTENING; 2716 rc = listening_get_idx(seq, &pos); 2717 2718 if (!rc) { 2719 st->state = TCP_SEQ_STATE_ESTABLISHED; 2720 rc = established_get_idx(seq, pos); 2721 } 2722 2723 return rc; 2724 } 2725 2726 static void *tcp_seek_last_pos(struct seq_file *seq) 2727 { 2728 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2729 struct tcp_iter_state *st = seq->private; 2730 int bucket = st->bucket; 2731 int offset = st->offset; 2732 int orig_num = st->num; 2733 void *rc = NULL; 2734 2735 switch (st->state) { 2736 case TCP_SEQ_STATE_LISTENING: 2737 if (st->bucket > hinfo->lhash2_mask) 2738 break; 2739 rc = listening_get_first(seq); 2740 while (offset-- && rc && bucket == st->bucket) 2741 rc = listening_get_next(seq, rc); 2742 if (rc) 2743 break; 2744 st->bucket = 0; 2745 st->state = TCP_SEQ_STATE_ESTABLISHED; 2746 fallthrough; 2747 case TCP_SEQ_STATE_ESTABLISHED: 2748 if (st->bucket > hinfo->ehash_mask) 2749 break; 2750 rc = established_get_first(seq); 2751 while (offset-- && rc && bucket == st->bucket) 2752 rc = established_get_next(seq, rc); 2753 } 2754 2755 st->num = orig_num; 2756 2757 return rc; 2758 } 2759 2760 void *tcp_seq_start(struct seq_file *seq, loff_t *pos) 2761 { 2762 struct tcp_iter_state *st = seq->private; 2763 void *rc; 2764 2765 if (*pos && *pos == st->last_pos) { 2766 rc = tcp_seek_last_pos(seq); 2767 if (rc) 2768 goto out; 2769 } 2770 2771 st->state = TCP_SEQ_STATE_LISTENING; 2772 st->num = 0; 2773 st->bucket = 0; 2774 st->offset = 0; 2775 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; 2776 2777 out: 2778 st->last_pos = *pos; 2779 return rc; 2780 } 2781 EXPORT_SYMBOL(tcp_seq_start); 2782 2783 void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2784 { 2785 struct tcp_iter_state *st = seq->private; 2786 void *rc = NULL; 2787 2788 if (v == SEQ_START_TOKEN) { 2789 rc = tcp_get_idx(seq, 0); 2790 goto out; 2791 } 2792 2793 switch (st->state) { 2794 case TCP_SEQ_STATE_LISTENING: 2795 rc = listening_get_next(seq, v); 2796 if (!rc) { 2797 st->state = TCP_SEQ_STATE_ESTABLISHED; 2798 st->bucket = 0; 2799 st->offset = 0; 2800 rc = established_get_first(seq); 2801 } 2802 break; 2803 case TCP_SEQ_STATE_ESTABLISHED: 2804 rc = established_get_next(seq, v); 2805 break; 2806 } 2807 out: 2808 ++*pos; 2809 st->last_pos = *pos; 2810 return rc; 2811 } 2812 EXPORT_SYMBOL(tcp_seq_next); 2813 2814 void tcp_seq_stop(struct seq_file *seq, void *v) 2815 { 2816 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 2817 struct tcp_iter_state *st = seq->private; 2818 2819 switch (st->state) { 2820 case TCP_SEQ_STATE_LISTENING: 2821 if (v != SEQ_START_TOKEN) 2822 spin_unlock(&hinfo->lhash2[st->bucket].lock); 2823 break; 2824 case TCP_SEQ_STATE_ESTABLISHED: 2825 if (v) 2826 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket)); 2827 break; 2828 } 2829 } 2830 EXPORT_SYMBOL(tcp_seq_stop); 2831 2832 static void get_openreq4(const struct request_sock *req, 2833 struct seq_file *f, int i) 2834 { 2835 const struct inet_request_sock *ireq = inet_rsk(req); 2836 long delta = req->rsk_timer.expires - jiffies; 2837 2838 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2839 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK", 2840 i, 2841 ireq->ir_loc_addr, 2842 ireq->ir_num, 2843 ireq->ir_rmt_addr, 2844 ntohs(ireq->ir_rmt_port), 2845 TCP_SYN_RECV, 2846 0, 0, /* could print option size, but that is af dependent. */ 2847 1, /* timers active (only the expire timer) */ 2848 jiffies_delta_to_clock_t(delta), 2849 req->num_timeout, 2850 from_kuid_munged(seq_user_ns(f), 2851 sock_i_uid(req->rsk_listener)), 2852 0, /* non standard timer */ 2853 0, /* open_requests have no inode */ 2854 0, 2855 req); 2856 } 2857 2858 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i) 2859 { 2860 int timer_active; 2861 unsigned long timer_expires; 2862 const struct tcp_sock *tp = tcp_sk(sk); 2863 const struct inet_connection_sock *icsk = inet_csk(sk); 2864 const struct inet_sock *inet = inet_sk(sk); 2865 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq; 2866 __be32 dest = inet->inet_daddr; 2867 __be32 src = inet->inet_rcv_saddr; 2868 __u16 destp = ntohs(inet->inet_dport); 2869 __u16 srcp = ntohs(inet->inet_sport); 2870 int rx_queue; 2871 int state; 2872 2873 if (icsk->icsk_pending == ICSK_TIME_RETRANS || 2874 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT || 2875 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { 2876 timer_active = 1; 2877 timer_expires = icsk->icsk_timeout; 2878 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { 2879 timer_active = 4; 2880 timer_expires = icsk->icsk_timeout; 2881 } else if (timer_pending(&sk->sk_timer)) { 2882 timer_active = 2; 2883 timer_expires = sk->sk_timer.expires; 2884 } else { 2885 timer_active = 0; 2886 timer_expires = jiffies; 2887 } 2888 2889 state = inet_sk_state_load(sk); 2890 if (state == TCP_LISTEN) 2891 rx_queue = READ_ONCE(sk->sk_ack_backlog); 2892 else 2893 /* Because we don't lock the socket, 2894 * we might find a transient negative value. 2895 */ 2896 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) - 2897 READ_ONCE(tp->copied_seq), 0); 2898 2899 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " 2900 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d", 2901 i, src, srcp, dest, destp, state, 2902 READ_ONCE(tp->write_seq) - tp->snd_una, 2903 rx_queue, 2904 timer_active, 2905 jiffies_delta_to_clock_t(timer_expires - jiffies), 2906 icsk->icsk_retransmits, 2907 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)), 2908 icsk->icsk_probes_out, 2909 sock_i_ino(sk), 2910 refcount_read(&sk->sk_refcnt), sk, 2911 jiffies_to_clock_t(icsk->icsk_rto), 2912 jiffies_to_clock_t(icsk->icsk_ack.ato), 2913 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk), 2914 tcp_snd_cwnd(tp), 2915 state == TCP_LISTEN ? 2916 fastopenq->max_qlen : 2917 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)); 2918 } 2919 2920 static void get_timewait4_sock(const struct inet_timewait_sock *tw, 2921 struct seq_file *f, int i) 2922 { 2923 long delta = tw->tw_timer.expires - jiffies; 2924 __be32 dest, src; 2925 __u16 destp, srcp; 2926 2927 dest = tw->tw_daddr; 2928 src = tw->tw_rcv_saddr; 2929 destp = ntohs(tw->tw_dport); 2930 srcp = ntohs(tw->tw_sport); 2931 2932 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2933 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK", 2934 i, src, srcp, dest, destp, tw->tw_substate, 0, 0, 2935 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, 2936 refcount_read(&tw->tw_refcnt), tw); 2937 } 2938 2939 #define TMPSZ 150 2940 2941 static int tcp4_seq_show(struct seq_file *seq, void *v) 2942 { 2943 struct tcp_iter_state *st; 2944 struct sock *sk = v; 2945 2946 seq_setwidth(seq, TMPSZ - 1); 2947 if (v == SEQ_START_TOKEN) { 2948 seq_puts(seq, " sl local_address rem_address st tx_queue " 2949 "rx_queue tr tm->when retrnsmt uid timeout " 2950 "inode"); 2951 goto out; 2952 } 2953 st = seq->private; 2954 2955 if (sk->sk_state == TCP_TIME_WAIT) 2956 get_timewait4_sock(v, seq, st->num); 2957 else if (sk->sk_state == TCP_NEW_SYN_RECV) 2958 get_openreq4(v, seq, st->num); 2959 else 2960 get_tcp4_sock(v, seq, st->num); 2961 out: 2962 seq_pad(seq, '\n'); 2963 return 0; 2964 } 2965 2966 #ifdef CONFIG_BPF_SYSCALL 2967 struct bpf_tcp_iter_state { 2968 struct tcp_iter_state state; 2969 unsigned int cur_sk; 2970 unsigned int end_sk; 2971 unsigned int max_sk; 2972 struct sock **batch; 2973 bool st_bucket_done; 2974 }; 2975 2976 struct bpf_iter__tcp { 2977 __bpf_md_ptr(struct bpf_iter_meta *, meta); 2978 __bpf_md_ptr(struct sock_common *, sk_common); 2979 uid_t uid __aligned(8); 2980 }; 2981 2982 static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta, 2983 struct sock_common *sk_common, uid_t uid) 2984 { 2985 struct bpf_iter__tcp ctx; 2986 2987 meta->seq_num--; /* skip SEQ_START_TOKEN */ 2988 ctx.meta = meta; 2989 ctx.sk_common = sk_common; 2990 ctx.uid = uid; 2991 return bpf_iter_run_prog(prog, &ctx); 2992 } 2993 2994 static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter) 2995 { 2996 while (iter->cur_sk < iter->end_sk) 2997 sock_gen_put(iter->batch[iter->cur_sk++]); 2998 } 2999 3000 static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter, 3001 unsigned int new_batch_sz) 3002 { 3003 struct sock **new_batch; 3004 3005 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz, 3006 GFP_USER | __GFP_NOWARN); 3007 if (!new_batch) 3008 return -ENOMEM; 3009 3010 bpf_iter_tcp_put_batch(iter); 3011 kvfree(iter->batch); 3012 iter->batch = new_batch; 3013 iter->max_sk = new_batch_sz; 3014 3015 return 0; 3016 } 3017 3018 static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq, 3019 struct sock *start_sk) 3020 { 3021 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 3022 struct bpf_tcp_iter_state *iter = seq->private; 3023 struct tcp_iter_state *st = &iter->state; 3024 struct hlist_nulls_node *node; 3025 unsigned int expected = 1; 3026 struct sock *sk; 3027 3028 sock_hold(start_sk); 3029 iter->batch[iter->end_sk++] = start_sk; 3030 3031 sk = sk_nulls_next(start_sk); 3032 sk_nulls_for_each_from(sk, node) { 3033 if (seq_sk_match(seq, sk)) { 3034 if (iter->end_sk < iter->max_sk) { 3035 sock_hold(sk); 3036 iter->batch[iter->end_sk++] = sk; 3037 } 3038 expected++; 3039 } 3040 } 3041 spin_unlock(&hinfo->lhash2[st->bucket].lock); 3042 3043 return expected; 3044 } 3045 3046 static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq, 3047 struct sock *start_sk) 3048 { 3049 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 3050 struct bpf_tcp_iter_state *iter = seq->private; 3051 struct tcp_iter_state *st = &iter->state; 3052 struct hlist_nulls_node *node; 3053 unsigned int expected = 1; 3054 struct sock *sk; 3055 3056 sock_hold(start_sk); 3057 iter->batch[iter->end_sk++] = start_sk; 3058 3059 sk = sk_nulls_next(start_sk); 3060 sk_nulls_for_each_from(sk, node) { 3061 if (seq_sk_match(seq, sk)) { 3062 if (iter->end_sk < iter->max_sk) { 3063 sock_hold(sk); 3064 iter->batch[iter->end_sk++] = sk; 3065 } 3066 expected++; 3067 } 3068 } 3069 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket)); 3070 3071 return expected; 3072 } 3073 3074 static struct sock *bpf_iter_tcp_batch(struct seq_file *seq) 3075 { 3076 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo; 3077 struct bpf_tcp_iter_state *iter = seq->private; 3078 struct tcp_iter_state *st = &iter->state; 3079 unsigned int expected; 3080 bool resized = false; 3081 struct sock *sk; 3082 3083 /* The st->bucket is done. Directly advance to the next 3084 * bucket instead of having the tcp_seek_last_pos() to skip 3085 * one by one in the current bucket and eventually find out 3086 * it has to advance to the next bucket. 3087 */ 3088 if (iter->st_bucket_done) { 3089 st->offset = 0; 3090 st->bucket++; 3091 if (st->state == TCP_SEQ_STATE_LISTENING && 3092 st->bucket > hinfo->lhash2_mask) { 3093 st->state = TCP_SEQ_STATE_ESTABLISHED; 3094 st->bucket = 0; 3095 } 3096 } 3097 3098 again: 3099 /* Get a new batch */ 3100 iter->cur_sk = 0; 3101 iter->end_sk = 0; 3102 iter->st_bucket_done = false; 3103 3104 sk = tcp_seek_last_pos(seq); 3105 if (!sk) 3106 return NULL; /* Done */ 3107 3108 if (st->state == TCP_SEQ_STATE_LISTENING) 3109 expected = bpf_iter_tcp_listening_batch(seq, sk); 3110 else 3111 expected = bpf_iter_tcp_established_batch(seq, sk); 3112 3113 if (iter->end_sk == expected) { 3114 iter->st_bucket_done = true; 3115 return sk; 3116 } 3117 3118 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) { 3119 resized = true; 3120 goto again; 3121 } 3122 3123 return sk; 3124 } 3125 3126 static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos) 3127 { 3128 /* bpf iter does not support lseek, so it always 3129 * continue from where it was stop()-ped. 3130 */ 3131 if (*pos) 3132 return bpf_iter_tcp_batch(seq); 3133 3134 return SEQ_START_TOKEN; 3135 } 3136 3137 static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 3138 { 3139 struct bpf_tcp_iter_state *iter = seq->private; 3140 struct tcp_iter_state *st = &iter->state; 3141 struct sock *sk; 3142 3143 /* Whenever seq_next() is called, the iter->cur_sk is 3144 * done with seq_show(), so advance to the next sk in 3145 * the batch. 3146 */ 3147 if (iter->cur_sk < iter->end_sk) { 3148 /* Keeping st->num consistent in tcp_iter_state. 3149 * bpf_iter_tcp does not use st->num. 3150 * meta.seq_num is used instead. 3151 */ 3152 st->num++; 3153 /* Move st->offset to the next sk in the bucket such that 3154 * the future start() will resume at st->offset in 3155 * st->bucket. See tcp_seek_last_pos(). 3156 */ 3157 st->offset++; 3158 sock_gen_put(iter->batch[iter->cur_sk++]); 3159 } 3160 3161 if (iter->cur_sk < iter->end_sk) 3162 sk = iter->batch[iter->cur_sk]; 3163 else 3164 sk = bpf_iter_tcp_batch(seq); 3165 3166 ++*pos; 3167 /* Keeping st->last_pos consistent in tcp_iter_state. 3168 * bpf iter does not do lseek, so st->last_pos always equals to *pos. 3169 */ 3170 st->last_pos = *pos; 3171 return sk; 3172 } 3173 3174 static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v) 3175 { 3176 struct bpf_iter_meta meta; 3177 struct bpf_prog *prog; 3178 struct sock *sk = v; 3179 uid_t uid; 3180 int ret; 3181 3182 if (v == SEQ_START_TOKEN) 3183 return 0; 3184 3185 if (sk_fullsock(sk)) 3186 lock_sock(sk); 3187 3188 if (unlikely(sk_unhashed(sk))) { 3189 ret = SEQ_SKIP; 3190 goto unlock; 3191 } 3192 3193 if (sk->sk_state == TCP_TIME_WAIT) { 3194 uid = 0; 3195 } else if (sk->sk_state == TCP_NEW_SYN_RECV) { 3196 const struct request_sock *req = v; 3197 3198 uid = from_kuid_munged(seq_user_ns(seq), 3199 sock_i_uid(req->rsk_listener)); 3200 } else { 3201 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)); 3202 } 3203 3204 meta.seq = seq; 3205 prog = bpf_iter_get_info(&meta, false); 3206 ret = tcp_prog_seq_show(prog, &meta, v, uid); 3207 3208 unlock: 3209 if (sk_fullsock(sk)) 3210 release_sock(sk); 3211 return ret; 3212 3213 } 3214 3215 static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v) 3216 { 3217 struct bpf_tcp_iter_state *iter = seq->private; 3218 struct bpf_iter_meta meta; 3219 struct bpf_prog *prog; 3220 3221 if (!v) { 3222 meta.seq = seq; 3223 prog = bpf_iter_get_info(&meta, true); 3224 if (prog) 3225 (void)tcp_prog_seq_show(prog, &meta, v, 0); 3226 } 3227 3228 if (iter->cur_sk < iter->end_sk) { 3229 bpf_iter_tcp_put_batch(iter); 3230 iter->st_bucket_done = false; 3231 } 3232 } 3233 3234 static const struct seq_operations bpf_iter_tcp_seq_ops = { 3235 .show = bpf_iter_tcp_seq_show, 3236 .start = bpf_iter_tcp_seq_start, 3237 .next = bpf_iter_tcp_seq_next, 3238 .stop = bpf_iter_tcp_seq_stop, 3239 }; 3240 #endif 3241 static unsigned short seq_file_family(const struct seq_file *seq) 3242 { 3243 const struct tcp_seq_afinfo *afinfo; 3244 3245 #ifdef CONFIG_BPF_SYSCALL 3246 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */ 3247 if (seq->op == &bpf_iter_tcp_seq_ops) 3248 return AF_UNSPEC; 3249 #endif 3250 3251 /* Iterated from proc fs */ 3252 afinfo = pde_data(file_inode(seq->file)); 3253 return afinfo->family; 3254 } 3255 3256 static const struct seq_operations tcp4_seq_ops = { 3257 .show = tcp4_seq_show, 3258 .start = tcp_seq_start, 3259 .next = tcp_seq_next, 3260 .stop = tcp_seq_stop, 3261 }; 3262 3263 static struct tcp_seq_afinfo tcp4_seq_afinfo = { 3264 .family = AF_INET, 3265 }; 3266 3267 static int __net_init tcp4_proc_init_net(struct net *net) 3268 { 3269 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops, 3270 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo)) 3271 return -ENOMEM; 3272 return 0; 3273 } 3274 3275 static void __net_exit tcp4_proc_exit_net(struct net *net) 3276 { 3277 remove_proc_entry("tcp", net->proc_net); 3278 } 3279 3280 static struct pernet_operations tcp4_net_ops = { 3281 .init = tcp4_proc_init_net, 3282 .exit = tcp4_proc_exit_net, 3283 }; 3284 3285 int __init tcp4_proc_init(void) 3286 { 3287 return register_pernet_subsys(&tcp4_net_ops); 3288 } 3289 3290 void tcp4_proc_exit(void) 3291 { 3292 unregister_pernet_subsys(&tcp4_net_ops); 3293 } 3294 #endif /* CONFIG_PROC_FS */ 3295 3296 /* @wake is one when sk_stream_write_space() calls us. 3297 * This sends EPOLLOUT only if notsent_bytes is half the limit. 3298 * This mimics the strategy used in sock_def_write_space(). 3299 */ 3300 bool tcp_stream_memory_free(const struct sock *sk, int wake) 3301 { 3302 const struct tcp_sock *tp = tcp_sk(sk); 3303 u32 notsent_bytes = READ_ONCE(tp->write_seq) - 3304 READ_ONCE(tp->snd_nxt); 3305 3306 return (notsent_bytes << wake) < tcp_notsent_lowat(tp); 3307 } 3308 EXPORT_SYMBOL(tcp_stream_memory_free); 3309 3310 struct proto tcp_prot = { 3311 .name = "TCP", 3312 .owner = THIS_MODULE, 3313 .close = tcp_close, 3314 .pre_connect = tcp_v4_pre_connect, 3315 .connect = tcp_v4_connect, 3316 .disconnect = tcp_disconnect, 3317 .accept = inet_csk_accept, 3318 .ioctl = tcp_ioctl, 3319 .init = tcp_v4_init_sock, 3320 .destroy = tcp_v4_destroy_sock, 3321 .shutdown = tcp_shutdown, 3322 .setsockopt = tcp_setsockopt, 3323 .getsockopt = tcp_getsockopt, 3324 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt, 3325 .keepalive = tcp_set_keepalive, 3326 .recvmsg = tcp_recvmsg, 3327 .sendmsg = tcp_sendmsg, 3328 .splice_eof = tcp_splice_eof, 3329 .backlog_rcv = tcp_v4_do_rcv, 3330 .release_cb = tcp_release_cb, 3331 .hash = inet_hash, 3332 .unhash = inet_unhash, 3333 .get_port = inet_csk_get_port, 3334 .put_port = inet_put_port, 3335 #ifdef CONFIG_BPF_SYSCALL 3336 .psock_update_sk_prot = tcp_bpf_update_proto, 3337 #endif 3338 .enter_memory_pressure = tcp_enter_memory_pressure, 3339 .leave_memory_pressure = tcp_leave_memory_pressure, 3340 .stream_memory_free = tcp_stream_memory_free, 3341 .sockets_allocated = &tcp_sockets_allocated, 3342 .orphan_count = &tcp_orphan_count, 3343 3344 .memory_allocated = &tcp_memory_allocated, 3345 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc, 3346 3347 .memory_pressure = &tcp_memory_pressure, 3348 .sysctl_mem = sysctl_tcp_mem, 3349 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 3350 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), 3351 .max_header = MAX_TCP_HEADER, 3352 .obj_size = sizeof(struct tcp_sock), 3353 .slab_flags = SLAB_TYPESAFE_BY_RCU, 3354 .twsk_prot = &tcp_timewait_sock_ops, 3355 .rsk_prot = &tcp_request_sock_ops, 3356 .h.hashinfo = NULL, 3357 .no_autobind = true, 3358 .diag_destroy = tcp_abort, 3359 }; 3360 EXPORT_SYMBOL(tcp_prot); 3361 3362 static void __net_exit tcp_sk_exit(struct net *net) 3363 { 3364 if (net->ipv4.tcp_congestion_control) 3365 bpf_module_put(net->ipv4.tcp_congestion_control, 3366 net->ipv4.tcp_congestion_control->owner); 3367 } 3368 3369 static void __net_init tcp_set_hashinfo(struct net *net) 3370 { 3371 struct inet_hashinfo *hinfo; 3372 unsigned int ehash_entries; 3373 struct net *old_net; 3374 3375 if (net_eq(net, &init_net)) 3376 goto fallback; 3377 3378 old_net = current->nsproxy->net_ns; 3379 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries); 3380 if (!ehash_entries) 3381 goto fallback; 3382 3383 ehash_entries = roundup_pow_of_two(ehash_entries); 3384 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries); 3385 if (!hinfo) { 3386 pr_warn("Failed to allocate TCP ehash (entries: %u) " 3387 "for a netns, fallback to the global one\n", 3388 ehash_entries); 3389 fallback: 3390 hinfo = &tcp_hashinfo; 3391 ehash_entries = tcp_hashinfo.ehash_mask + 1; 3392 } 3393 3394 net->ipv4.tcp_death_row.hashinfo = hinfo; 3395 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2; 3396 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128); 3397 } 3398 3399 static int __net_init tcp_sk_init(struct net *net) 3400 { 3401 net->ipv4.sysctl_tcp_ecn = 2; 3402 net->ipv4.sysctl_tcp_ecn_fallback = 1; 3403 3404 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS; 3405 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS; 3406 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD; 3407 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL; 3408 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS; 3409 3410 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME; 3411 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES; 3412 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL; 3413 3414 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES; 3415 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES; 3416 net->ipv4.sysctl_tcp_syncookies = 1; 3417 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH; 3418 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1; 3419 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2; 3420 net->ipv4.sysctl_tcp_orphan_retries = 0; 3421 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT; 3422 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX; 3423 net->ipv4.sysctl_tcp_tw_reuse = 2; 3424 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1; 3425 3426 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1); 3427 tcp_set_hashinfo(net); 3428 3429 net->ipv4.sysctl_tcp_sack = 1; 3430 net->ipv4.sysctl_tcp_window_scaling = 1; 3431 net->ipv4.sysctl_tcp_timestamps = 1; 3432 net->ipv4.sysctl_tcp_early_retrans = 3; 3433 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION; 3434 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */ 3435 net->ipv4.sysctl_tcp_retrans_collapse = 1; 3436 net->ipv4.sysctl_tcp_max_reordering = 300; 3437 net->ipv4.sysctl_tcp_dsack = 1; 3438 net->ipv4.sysctl_tcp_app_win = 31; 3439 net->ipv4.sysctl_tcp_adv_win_scale = 1; 3440 net->ipv4.sysctl_tcp_frto = 2; 3441 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1; 3442 /* This limits the percentage of the congestion window which we 3443 * will allow a single TSO frame to consume. Building TSO frames 3444 * which are too large can cause TCP streams to be bursty. 3445 */ 3446 net->ipv4.sysctl_tcp_tso_win_divisor = 3; 3447 /* Default TSQ limit of 16 TSO segments */ 3448 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536; 3449 3450 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */ 3451 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX; 3452 3453 net->ipv4.sysctl_tcp_min_tso_segs = 2; 3454 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */ 3455 net->ipv4.sysctl_tcp_min_rtt_wlen = 300; 3456 net->ipv4.sysctl_tcp_autocorking = 1; 3457 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2; 3458 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200; 3459 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120; 3460 if (net != &init_net) { 3461 memcpy(net->ipv4.sysctl_tcp_rmem, 3462 init_net.ipv4.sysctl_tcp_rmem, 3463 sizeof(init_net.ipv4.sysctl_tcp_rmem)); 3464 memcpy(net->ipv4.sysctl_tcp_wmem, 3465 init_net.ipv4.sysctl_tcp_wmem, 3466 sizeof(init_net.ipv4.sysctl_tcp_wmem)); 3467 } 3468 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC; 3469 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC; 3470 net->ipv4.sysctl_tcp_comp_sack_nr = 44; 3471 net->ipv4.sysctl_tcp_backlog_ack_defer = 1; 3472 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE; 3473 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0; 3474 atomic_set(&net->ipv4.tfo_active_disable_times, 0); 3475 3476 /* Set default values for PLB */ 3477 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */ 3478 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3; 3479 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12; 3480 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60; 3481 /* Default congestion threshold for PLB to mark a round is 50% */ 3482 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2; 3483 3484 /* Reno is always built in */ 3485 if (!net_eq(net, &init_net) && 3486 bpf_try_module_get(init_net.ipv4.tcp_congestion_control, 3487 init_net.ipv4.tcp_congestion_control->owner)) 3488 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control; 3489 else 3490 net->ipv4.tcp_congestion_control = &tcp_reno; 3491 3492 net->ipv4.sysctl_tcp_syn_linear_timeouts = 4; 3493 net->ipv4.sysctl_tcp_shrink_window = 0; 3494 3495 net->ipv4.sysctl_tcp_pingpong_thresh = 1; 3496 3497 return 0; 3498 } 3499 3500 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list) 3501 { 3502 struct net *net; 3503 3504 tcp_twsk_purge(net_exit_list, AF_INET); 3505 3506 list_for_each_entry(net, net_exit_list, exit_list) { 3507 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo); 3508 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount)); 3509 tcp_fastopen_ctx_destroy(net); 3510 } 3511 } 3512 3513 static struct pernet_operations __net_initdata tcp_sk_ops = { 3514 .init = tcp_sk_init, 3515 .exit = tcp_sk_exit, 3516 .exit_batch = tcp_sk_exit_batch, 3517 }; 3518 3519 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 3520 DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta, 3521 struct sock_common *sk_common, uid_t uid) 3522 3523 #define INIT_BATCH_SZ 16 3524 3525 static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux) 3526 { 3527 struct bpf_tcp_iter_state *iter = priv_data; 3528 int err; 3529 3530 err = bpf_iter_init_seq_net(priv_data, aux); 3531 if (err) 3532 return err; 3533 3534 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ); 3535 if (err) { 3536 bpf_iter_fini_seq_net(priv_data); 3537 return err; 3538 } 3539 3540 return 0; 3541 } 3542 3543 static void bpf_iter_fini_tcp(void *priv_data) 3544 { 3545 struct bpf_tcp_iter_state *iter = priv_data; 3546 3547 bpf_iter_fini_seq_net(priv_data); 3548 kvfree(iter->batch); 3549 } 3550 3551 static const struct bpf_iter_seq_info tcp_seq_info = { 3552 .seq_ops = &bpf_iter_tcp_seq_ops, 3553 .init_seq_private = bpf_iter_init_tcp, 3554 .fini_seq_private = bpf_iter_fini_tcp, 3555 .seq_priv_size = sizeof(struct bpf_tcp_iter_state), 3556 }; 3557 3558 static const struct bpf_func_proto * 3559 bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id, 3560 const struct bpf_prog *prog) 3561 { 3562 switch (func_id) { 3563 case BPF_FUNC_setsockopt: 3564 return &bpf_sk_setsockopt_proto; 3565 case BPF_FUNC_getsockopt: 3566 return &bpf_sk_getsockopt_proto; 3567 default: 3568 return NULL; 3569 } 3570 } 3571 3572 static struct bpf_iter_reg tcp_reg_info = { 3573 .target = "tcp", 3574 .ctx_arg_info_size = 1, 3575 .ctx_arg_info = { 3576 { offsetof(struct bpf_iter__tcp, sk_common), 3577 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED }, 3578 }, 3579 .get_func_proto = bpf_iter_tcp_get_func_proto, 3580 .seq_info = &tcp_seq_info, 3581 }; 3582 3583 static void __init bpf_iter_register(void) 3584 { 3585 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON]; 3586 if (bpf_iter_reg_target(&tcp_reg_info)) 3587 pr_warn("Warning: could not register bpf iterator tcp\n"); 3588 } 3589 3590 #endif 3591 3592 void __init tcp_v4_init(void) 3593 { 3594 int cpu, res; 3595 3596 for_each_possible_cpu(cpu) { 3597 struct sock *sk; 3598 3599 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW, 3600 IPPROTO_TCP, &init_net); 3601 if (res) 3602 panic("Failed to create the TCP control socket.\n"); 3603 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 3604 3605 /* Please enforce IP_DF and IPID==0 for RST and 3606 * ACK sent in SYN-RECV and TIME-WAIT state. 3607 */ 3608 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO; 3609 3610 per_cpu(ipv4_tcp_sk, cpu) = sk; 3611 } 3612 if (register_pernet_subsys(&tcp_sk_ops)) 3613 panic("Failed to create the TCP control socket.\n"); 3614 3615 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 3616 bpf_iter_register(); 3617 #endif 3618 } 3619