1/* $OpenBSD: tcp_subr.c,v 1.201 2024/04/17 20:48:51 bluhm Exp $ */ 2/* $NetBSD: tcp_subr.c,v 1.22 1996/02/13 23:44:00 christos Exp $ */ 3 4/* 5 * Copyright (c) 1982, 1986, 1988, 1990, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)COPYRIGHT 1.1 (NRL) 17 January 1995 33 * 34 * NRL grants permission for redistribution and use in source and binary 35 * forms, with or without modification, of the software and documentation 36 * created at NRL provided that the following conditions are met: 37 * 38 * 1. Redistributions of source code must retain the above copyright 39 * notice, this list of conditions and the following disclaimer. 40 * 2. Redistributions in binary form must reproduce the above copyright 41 * notice, this list of conditions and the following disclaimer in the 42 * documentation and/or other materials provided with the distribution. 43 * 3. All advertising materials mentioning features or use of this software 44 * must display the following acknowledgements: 45 * This product includes software developed by the University of 46 * California, Berkeley and its contributors. 47 * This product includes software developed at the Information 48 * Technology Division, US Naval Research Laboratory. 49 * 4. Neither the name of the NRL nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL AND CONTRIBUTORS ``AS 54 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 55 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 56 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NRL OR 57 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 58 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 59 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 60 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 61 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 62 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 63 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 64 * 65 * The views and conclusions contained in the software and documentation 66 * are those of the authors and should not be interpreted as representing 67 * official policies, either expressed or implied, of the US Naval 68 * Research Laboratory (NRL). 69 */ 70 71#include <sys/param.h> 72#include <sys/systm.h> 73#include <sys/mbuf.h> 74#include <sys/mutex.h> 75#include <sys/socket.h> 76#include <sys/socketvar.h> 77#include <sys/timeout.h> 78#include <sys/protosw.h> 79#include <sys/kernel.h> 80#include <sys/pool.h> 81 82#include <net/route.h> 83 84#include <netinet/in.h> 85#include <netinet/ip.h> 86#include <netinet/in_pcb.h> 87#include <netinet/ip_var.h> 88#include <netinet6/ip6_var.h> 89#include <netinet/ip_icmp.h> 90#include <netinet/tcp.h> 91#include <netinet/tcp_fsm.h> 92#include <netinet/tcp_seq.h> 93#include <netinet/tcp_timer.h> 94#include <netinet/tcp_var.h> 95 96#ifdef INET6 97#include <netinet6/ip6protosw.h> 98#endif /* INET6 */ 99 100#include <crypto/md5.h> 101#include <crypto/sha2.h> 102 103/* 104 * Locks used to protect struct members in this file: 105 * I immutable after creation 106 * T tcp_timer_mtx global tcp timer data structures 107 */ 108 109struct mutex tcp_timer_mtx = MUTEX_INITIALIZER(IPL_SOFTNET); 110 111/* patchable/settable parameters for tcp */ 112int tcp_mssdflt = TCP_MSS; 113int tcp_rttdflt = TCPTV_SRTTDFLT; 114 115/* values controllable via sysctl */ 116int tcp_do_rfc1323 = 1; 117int tcp_do_sack = 1; /* RFC 2018 selective ACKs */ 118int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ 119#ifdef TCP_ECN 120int tcp_do_ecn = 0; /* RFC3168 ECN enabled/disabled? */ 121#endif 122int tcp_do_rfc3390 = 2; /* Increase TCP's Initial Window to 10*mss */ 123int tcp_do_tso = 1; /* TCP segmentation offload for output */ 124 125#ifndef TCB_INITIAL_HASH_SIZE 126#define TCB_INITIAL_HASH_SIZE 128 127#endif 128 129int tcp_reass_limit = NMBCLUSTERS / 8; /* hardlimit for tcpqe_pool */ 130int tcp_sackhole_limit = 32*1024; /* hardlimit for sackhl_pool */ 131 132struct pool tcpcb_pool; 133struct pool tcpqe_pool; 134struct pool sackhl_pool; 135 136struct cpumem *tcpcounters; /* tcp statistics */ 137 138u_char tcp_secret[16]; /* [I] */ 139SHA2_CTX tcp_secret_ctx; /* [I] */ 140tcp_seq tcp_iss; /* [T] updated by timer and connection */ 141uint64_t tcp_starttime; /* [I] random offset for tcp_now() */ 142 143/* 144 * Tcp initialization 145 */ 146void 147tcp_init(void) 148{ 149 tcp_iss = 1; /* wrong */ 150 /* 0 is treated special so add 1, 63 bits to count is enough */ 151 arc4random_buf(&tcp_starttime, sizeof(tcp_starttime)); 152 tcp_starttime = 1ULL + (tcp_starttime / 2); 153 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, IPL_SOFTNET, 0, 154 "tcpcb", NULL); 155 pool_init(&tcpqe_pool, sizeof(struct tcpqent), 0, IPL_SOFTNET, 0, 156 "tcpqe", NULL); 157 pool_sethardlimit(&tcpqe_pool, tcp_reass_limit, NULL, 0); 158 pool_init(&sackhl_pool, sizeof(struct sackhole), 0, IPL_SOFTNET, 0, 159 "sackhl", NULL); 160 pool_sethardlimit(&sackhl_pool, tcp_sackhole_limit, NULL, 0); 161 in_pcbinit(&tcbtable, TCB_INITIAL_HASH_SIZE); 162#ifdef INET6 163 in_pcbinit(&tcb6table, TCB_INITIAL_HASH_SIZE); 164#endif 165 tcpcounters = counters_alloc(tcps_ncounters); 166 167 arc4random_buf(tcp_secret, sizeof(tcp_secret)); 168 SHA512Init(&tcp_secret_ctx); 169 SHA512Update(&tcp_secret_ctx, tcp_secret, sizeof(tcp_secret)); 170 171#ifdef INET6 172 /* 173 * Since sizeof(struct ip6_hdr) > sizeof(struct ip), we 174 * do max length checks/computations only on the former. 175 */ 176 if (max_protohdr < (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))) 177 max_protohdr = (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)); 178 if ((max_linkhdr + sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) > 179 MHLEN) 180 panic("tcp_init"); 181 182 icmp6_mtudisc_callback_register(tcp6_mtudisc_callback); 183#endif /* INET6 */ 184 185 /* Initialize the compressed state engine. */ 186 syn_cache_init(); 187 188 /* Initialize timer state. */ 189 tcp_timer_init(); 190} 191 192/* 193 * Create template to be used to send tcp packets on a connection. 194 * Call after host entry created, allocates an mbuf and fills 195 * in a skeletal tcp/ip header, minimizing the amount of work 196 * necessary when the connection is used. 197 * 198 * To support IPv6 in addition to IPv4 and considering that the sizes of 199 * the IPv4 and IPv6 headers are not the same, we now use a separate pointer 200 * for the TCP header. Also, we made the former tcpiphdr header pointer 201 * into just an IP overlay pointer, with casting as appropriate for v6. rja 202 */ 203struct mbuf * 204tcp_template(struct tcpcb *tp) 205{ 206 struct inpcb *inp = tp->t_inpcb; 207 struct mbuf *m; 208 struct tcphdr *th; 209 210 CTASSERT(sizeof(struct ip) + sizeof(struct tcphdr) <= MHLEN); 211 CTASSERT(sizeof(struct ip6_hdr) + sizeof(struct tcphdr) <= MHLEN); 212 213 if ((m = tp->t_template) == 0) { 214 m = m_get(M_DONTWAIT, MT_HEADER); 215 if (m == NULL) 216 return (0); 217 218 switch (tp->pf) { 219 case 0: /*default to PF_INET*/ 220 case AF_INET: 221 m->m_len = sizeof(struct ip); 222 break; 223#ifdef INET6 224 case AF_INET6: 225 m->m_len = sizeof(struct ip6_hdr); 226 break; 227#endif /* INET6 */ 228 } 229 m->m_len += sizeof (struct tcphdr); 230 } 231 232 switch(tp->pf) { 233 case AF_INET: 234 { 235 struct ipovly *ipovly; 236 237 ipovly = mtod(m, struct ipovly *); 238 239 bzero(ipovly->ih_x1, sizeof ipovly->ih_x1); 240 ipovly->ih_pr = IPPROTO_TCP; 241 ipovly->ih_len = htons(sizeof (struct tcphdr)); 242 ipovly->ih_src = inp->inp_laddr; 243 ipovly->ih_dst = inp->inp_faddr; 244 245 th = (struct tcphdr *)(mtod(m, caddr_t) + 246 sizeof(struct ip)); 247 } 248 break; 249#ifdef INET6 250 case AF_INET6: 251 { 252 struct ip6_hdr *ip6; 253 254 ip6 = mtod(m, struct ip6_hdr *); 255 256 ip6->ip6_src = inp->inp_laddr6; 257 ip6->ip6_dst = inp->inp_faddr6; 258 ip6->ip6_flow = htonl(0x60000000) | 259 (inp->inp_flowinfo & IPV6_FLOWLABEL_MASK); 260 261 ip6->ip6_nxt = IPPROTO_TCP; 262 ip6->ip6_plen = htons(sizeof(struct tcphdr)); /*XXX*/ 263 ip6->ip6_hlim = in6_selecthlim(inp); /*XXX*/ 264 265 th = (struct tcphdr *)(mtod(m, caddr_t) + 266 sizeof(struct ip6_hdr)); 267 } 268 break; 269#endif /* INET6 */ 270 } 271 272 th->th_sport = inp->inp_lport; 273 th->th_dport = inp->inp_fport; 274 th->th_seq = 0; 275 th->th_ack = 0; 276 th->th_x2 = 0; 277 th->th_off = 5; 278 th->th_flags = 0; 279 th->th_win = 0; 280 th->th_urp = 0; 281 th->th_sum = 0; 282 return (m); 283} 284 285/* 286 * Send a single message to the TCP at address specified by 287 * the given TCP/IP header. If m == 0, then we make a copy 288 * of the tcpiphdr at ti and send directly to the addressed host. 289 * This is used to force keep alive messages out using the TCP 290 * template for a connection tp->t_template. If flags are given 291 * then we send a message back to the TCP which originated the 292 * segment ti, and discard the mbuf containing it and any other 293 * attached mbufs. 294 * 295 * In any case the ack and sequence number of the transmitted 296 * segment are as specified by the parameters. 297 */ 298void 299tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0, 300 tcp_seq ack, tcp_seq seq, int flags, u_int rtableid, uint64_t now) 301{ 302 int tlen; 303 int win = 0; 304 struct mbuf *m = NULL; 305 struct tcphdr *th; 306 struct ip *ip; 307#ifdef INET6 308 struct ip6_hdr *ip6; 309#endif 310 int af; /* af on wire */ 311 312 if (tp) { 313 struct socket *so = tp->t_inpcb->inp_socket; 314 win = sbspace(so, &so->so_rcv); 315 /* 316 * If this is called with an unconnected 317 * socket/tp/pcb (tp->pf is 0), we lose. 318 */ 319 af = tp->pf; 320 } else 321 af = (((struct ip *)template)->ip_v == 6) ? AF_INET6 : AF_INET; 322 323 m = m_gethdr(M_DONTWAIT, MT_HEADER); 324 if (m == NULL) 325 return; 326 m->m_data += max_linkhdr; 327 tlen = 0; 328 329#define xchg(a,b,type) do { type t; t=a; a=b; b=t; } while (0) 330 switch (af) { 331#ifdef INET6 332 case AF_INET6: 333 ip6 = mtod(m, struct ip6_hdr *); 334 th = (struct tcphdr *)(ip6 + 1); 335 tlen = sizeof(*ip6) + sizeof(*th); 336 if (th0) { 337 bcopy(template, ip6, sizeof(*ip6)); 338 bcopy(th0, th, sizeof(*th)); 339 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 340 } else { 341 bcopy(template, ip6, tlen); 342 } 343 break; 344#endif /* INET6 */ 345 case AF_INET: 346 ip = mtod(m, struct ip *); 347 th = (struct tcphdr *)(ip + 1); 348 tlen = sizeof(*ip) + sizeof(*th); 349 if (th0) { 350 bcopy(template, ip, sizeof(*ip)); 351 bcopy(th0, th, sizeof(*th)); 352 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, u_int32_t); 353 } else { 354 bcopy(template, ip, tlen); 355 } 356 break; 357 } 358 if (th0) 359 xchg(th->th_dport, th->th_sport, u_int16_t); 360 else 361 flags = TH_ACK; 362#undef xchg 363 364 th->th_seq = htonl(seq); 365 th->th_ack = htonl(ack); 366 th->th_x2 = 0; 367 th->th_off = sizeof (struct tcphdr) >> 2; 368 th->th_flags = flags; 369 if (tp) 370 win >>= tp->rcv_scale; 371 if (win > TCP_MAXWIN) 372 win = TCP_MAXWIN; 373 th->th_win = htons((u_int16_t)win); 374 th->th_urp = 0; 375 376 if (tp && (tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 377 (flags & TH_RST) == 0 && (tp->t_flags & TF_RCVD_TSTMP)) { 378 u_int32_t *lp = (u_int32_t *)(th + 1); 379 /* Form timestamp option as shown in appendix A of RFC 1323. */ 380 *lp++ = htonl(TCPOPT_TSTAMP_HDR); 381 *lp++ = htonl(now + tp->ts_modulate); 382 *lp = htonl(tp->ts_recent); 383 tlen += TCPOLEN_TSTAMP_APPA; 384 th->th_off = (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_APPA) >> 2; 385 } 386 387 m->m_len = tlen; 388 m->m_pkthdr.len = tlen; 389 m->m_pkthdr.ph_ifidx = 0; 390 m->m_pkthdr.csum_flags |= M_TCP_CSUM_OUT; 391 392 /* force routing table */ 393 if (tp) 394 m->m_pkthdr.ph_rtableid = tp->t_inpcb->inp_rtableid; 395 else 396 m->m_pkthdr.ph_rtableid = rtableid; 397 398 switch (af) { 399#ifdef INET6 400 case AF_INET6: 401 ip6->ip6_flow = htonl(0x60000000); 402 ip6->ip6_nxt = IPPROTO_TCP; 403 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL); /*XXX*/ 404 ip6->ip6_plen = tlen - sizeof(struct ip6_hdr); 405 ip6->ip6_plen = htons(ip6->ip6_plen); 406 ip6_output(m, tp ? tp->t_inpcb->inp_outputopts6 : NULL, 407 tp ? &tp->t_inpcb->inp_route : NULL, 408 0, NULL, 409 tp ? &tp->t_inpcb->inp_seclevel : NULL); 410 break; 411#endif /* INET6 */ 412 case AF_INET: 413 ip->ip_len = htons(tlen); 414 ip->ip_ttl = ip_defttl; 415 ip->ip_tos = 0; 416 ip_output(m, NULL, 417 tp ? &tp->t_inpcb->inp_route : NULL, 418 ip_mtudisc ? IP_MTUDISC : 0, NULL, 419 tp ? &tp->t_inpcb->inp_seclevel : NULL, 0); 420 break; 421 } 422} 423 424/* 425 * Create a new TCP control block, making an 426 * empty reassembly queue and hooking it to the argument 427 * protocol control block. 428 */ 429struct tcpcb * 430tcp_newtcpcb(struct inpcb *inp, int wait) 431{ 432 struct tcpcb *tp; 433 int i; 434 435 tp = pool_get(&tcpcb_pool, (wait == M_WAIT ? PR_WAITOK : PR_NOWAIT) | 436 PR_ZERO); 437 if (tp == NULL) 438 return (NULL); 439 TAILQ_INIT(&tp->t_segq); 440 tp->t_maxseg = tcp_mssdflt; 441 tp->t_maxopd = 0; 442 443 for (i = 0; i < TCPT_NTIMERS; i++) 444 TCP_TIMER_INIT(tp, i); 445 446 tp->sack_enable = tcp_do_sack; 447 tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; 448 tp->t_inpcb = inp; 449 /* 450 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 451 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 452 * reasonable initial retransmit time. 453 */ 454 tp->t_srtt = TCPTV_SRTTBASE; 455 tp->t_rttvar = tcp_rttdflt << 456 (TCP_RTTVAR_SHIFT + TCP_RTT_BASE_SHIFT - 1); 457 tp->t_rttmin = TCPTV_MIN; 458 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 459 TCPTV_MIN, TCPTV_REXMTMAX); 460 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 461 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 462 463 tp->t_pmtud_mtu_sent = 0; 464 tp->t_pmtud_mss_acked = 0; 465 466#ifdef INET6 467 if (ISSET(inp->inp_flags, INP_IPV6)) { 468 tp->pf = PF_INET6; 469 inp->inp_ipv6.ip6_hlim = ip6_defhlim; 470 } else 471#endif 472 { 473 tp->pf = PF_INET; 474 inp->inp_ip.ip_ttl = ip_defttl; 475 } 476 477 inp->inp_ppcb = (caddr_t)tp; 478 return (tp); 479} 480 481/* 482 * Drop a TCP connection, reporting 483 * the specified error. If connection is synchronized, 484 * then send a RST to peer. 485 */ 486struct tcpcb * 487tcp_drop(struct tcpcb *tp, int errno) 488{ 489 struct socket *so = tp->t_inpcb->inp_socket; 490 491 if (TCPS_HAVERCVDSYN(tp->t_state)) { 492 tp->t_state = TCPS_CLOSED; 493 (void) tcp_output(tp); 494 tcpstat_inc(tcps_drops); 495 } else 496 tcpstat_inc(tcps_conndrops); 497 if (errno == ETIMEDOUT && tp->t_softerror) 498 errno = tp->t_softerror; 499 so->so_error = errno; 500 return (tcp_close(tp)); 501} 502 503/* 504 * Close a TCP control block: 505 * discard all space held by the tcp 506 * discard internet protocol block 507 * wake up any sleepers 508 */ 509struct tcpcb * 510tcp_close(struct tcpcb *tp) 511{ 512 struct inpcb *inp = tp->t_inpcb; 513 struct socket *so = inp->inp_socket; 514 struct sackhole *p, *q; 515 516 /* free the reassembly queue, if any */ 517 tcp_freeq(tp); 518 519 tcp_canceltimers(tp); 520 syn_cache_cleanup(tp); 521 522 /* Free SACK holes. */ 523 q = p = tp->snd_holes; 524 while (p != 0) { 525 q = p->next; 526 pool_put(&sackhl_pool, p); 527 p = q; 528 } 529 530 m_free(tp->t_template); 531 /* Free tcpcb after all pending timers have been run. */ 532 TCP_TIMER_ARM(tp, TCPT_REAPER, 1); 533 534 inp->inp_ppcb = NULL; 535 soisdisconnected(so); 536 in_pcbdetach(inp); 537 return (NULL); 538} 539 540int 541tcp_freeq(struct tcpcb *tp) 542{ 543 struct tcpqent *qe; 544 int rv = 0; 545 546 while ((qe = TAILQ_FIRST(&tp->t_segq)) != NULL) { 547 TAILQ_REMOVE(&tp->t_segq, qe, tcpqe_q); 548 m_freem(qe->tcpqe_m); 549 pool_put(&tcpqe_pool, qe); 550 rv = 1; 551 } 552 return (rv); 553} 554 555/* 556 * Compute proper scaling value for receiver window from buffer space 557 */ 558 559void 560tcp_rscale(struct tcpcb *tp, u_long hiwat) 561{ 562 tp->request_r_scale = 0; 563 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 564 TCP_MAXWIN << tp->request_r_scale < hiwat) 565 tp->request_r_scale++; 566} 567 568/* 569 * Notify a tcp user of an asynchronous error; 570 * store error as soft error, but wake up user 571 * (for now, won't do anything until can select for soft error). 572 */ 573void 574tcp_notify(struct inpcb *inp, int error) 575{ 576 struct tcpcb *tp = intotcpcb(inp); 577 struct socket *so = inp->inp_socket; 578 579 /* 580 * Ignore some errors if we are hooked up. 581 * If connection hasn't completed, has retransmitted several times, 582 * and receives a second error, give up now. This is better 583 * than waiting a long time to establish a connection that 584 * can never complete. 585 */ 586 if (tp->t_state == TCPS_ESTABLISHED && 587 (error == EHOSTUNREACH || error == ENETUNREACH || 588 error == EHOSTDOWN)) { 589 return; 590 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 591 tp->t_rxtshift > 3 && tp->t_softerror) 592 so->so_error = error; 593 else 594 tp->t_softerror = error; 595 wakeup((caddr_t) &so->so_timeo); 596 sorwakeup(so); 597 sowwakeup(so); 598} 599 600#ifdef INET6 601void 602tcp6_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *d) 603{ 604 struct tcphdr th; 605 struct tcpcb *tp; 606 void (*notify)(struct inpcb *, int) = tcp_notify; 607 struct ip6_hdr *ip6; 608 const struct sockaddr_in6 *sa6_src = NULL; 609 struct sockaddr_in6 *sa6 = satosin6(sa); 610 struct inpcb *inp; 611 struct mbuf *m; 612 tcp_seq seq; 613 int off; 614 struct { 615 u_int16_t th_sport; 616 u_int16_t th_dport; 617 u_int32_t th_seq; 618 } *thp; 619 620 CTASSERT(sizeof(*thp) <= sizeof(th)); 621 if (sa->sa_family != AF_INET6 || 622 sa->sa_len != sizeof(struct sockaddr_in6) || 623 IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) || 624 IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) 625 return; 626 if ((unsigned)cmd >= PRC_NCMDS) 627 return; 628 else if (cmd == PRC_QUENCH) { 629 /* 630 * Don't honor ICMP Source Quench messages meant for 631 * TCP connections. 632 */ 633 /* XXX there's no PRC_QUENCH in IPv6 */ 634 return; 635 } else if (PRC_IS_REDIRECT(cmd)) 636 notify = in_rtchange, d = NULL; 637 else if (cmd == PRC_MSGSIZE) 638 ; /* special code is present, see below */ 639 else if (cmd == PRC_HOSTDEAD) 640 d = NULL; 641 else if (inet6ctlerrmap[cmd] == 0) 642 return; 643 644 /* if the parameter is from icmp6, decode it. */ 645 if (d != NULL) { 646 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 647 m = ip6cp->ip6c_m; 648 ip6 = ip6cp->ip6c_ip6; 649 off = ip6cp->ip6c_off; 650 sa6_src = ip6cp->ip6c_src; 651 } else { 652 m = NULL; 653 ip6 = NULL; 654 sa6_src = &sa6_any; 655 } 656 657 if (ip6) { 658 /* 659 * XXX: We assume that when ip6 is non NULL, 660 * M and OFF are valid. 661 */ 662 663 /* check if we can safely examine src and dst ports */ 664 if (m->m_pkthdr.len < off + sizeof(*thp)) 665 return; 666 667 bzero(&th, sizeof(th)); 668 m_copydata(m, off, sizeof(*thp), &th); 669 670 /* 671 * Check to see if we have a valid TCP connection 672 * corresponding to the address in the ICMPv6 message 673 * payload. 674 */ 675 inp = in6_pcblookup(&tcb6table, &sa6->sin6_addr, 676 th.th_dport, &sa6_src->sin6_addr, th.th_sport, rdomain); 677 if (cmd == PRC_MSGSIZE) { 678 /* 679 * Depending on the value of "valid" and routing table 680 * size (mtudisc_{hi,lo}wat), we will: 681 * - recalculate the new MTU and create the 682 * corresponding routing entry, or 683 * - ignore the MTU change notification. 684 */ 685 icmp6_mtudisc_update((struct ip6ctlparam *)d, 686 inp != NULL); 687 in_pcbunref(inp); 688 return; 689 } 690 if (inp) { 691 seq = ntohl(th.th_seq); 692 if ((tp = intotcpcb(inp)) && 693 SEQ_GEQ(seq, tp->snd_una) && 694 SEQ_LT(seq, tp->snd_max)) 695 notify(inp, inet6ctlerrmap[cmd]); 696 } else if (inet6ctlerrmap[cmd] == EHOSTUNREACH || 697 inet6ctlerrmap[cmd] == ENETUNREACH || 698 inet6ctlerrmap[cmd] == EHOSTDOWN) 699 syn_cache_unreach(sin6tosa_const(sa6_src), sa, &th, 700 rdomain); 701 in_pcbunref(inp); 702 } else { 703 in6_pcbnotify(&tcb6table, sa6, 0, 704 sa6_src, 0, rdomain, cmd, NULL, notify); 705 } 706} 707#endif 708 709void 710tcp_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *v) 711{ 712 struct ip *ip = v; 713 struct tcphdr *th; 714 struct tcpcb *tp; 715 struct inpcb *inp; 716 struct in_addr faddr; 717 tcp_seq seq; 718 u_int mtu; 719 void (*notify)(struct inpcb *, int) = tcp_notify; 720 int errno; 721 722 if (sa->sa_family != AF_INET) 723 return; 724 faddr = satosin(sa)->sin_addr; 725 if (faddr.s_addr == INADDR_ANY) 726 return; 727 728 if ((unsigned)cmd >= PRC_NCMDS) 729 return; 730 errno = inetctlerrmap[cmd]; 731 if (cmd == PRC_QUENCH) 732 /* 733 * Don't honor ICMP Source Quench messages meant for 734 * TCP connections. 735 */ 736 return; 737 else if (PRC_IS_REDIRECT(cmd)) 738 notify = in_rtchange, ip = 0; 739 else if (cmd == PRC_MSGSIZE && ip_mtudisc && ip) { 740 /* 741 * Verify that the packet in the icmp payload refers 742 * to an existing TCP connection. 743 */ 744 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 745 seq = ntohl(th->th_seq); 746 inp = in_pcblookup(&tcbtable, 747 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 748 rdomain); 749 if (inp && (tp = intotcpcb(inp)) && 750 SEQ_GEQ(seq, tp->snd_una) && 751 SEQ_LT(seq, tp->snd_max)) { 752 struct icmp *icp; 753 icp = (struct icmp *)((caddr_t)ip - 754 offsetof(struct icmp, icmp_ip)); 755 756 /* 757 * If the ICMP message advertises a Next-Hop MTU 758 * equal or larger than the maximum packet size we have 759 * ever sent, drop the message. 760 */ 761 mtu = (u_int)ntohs(icp->icmp_nextmtu); 762 if (mtu >= tp->t_pmtud_mtu_sent) { 763 in_pcbunref(inp); 764 return; 765 } 766 if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) { 767 /* 768 * Calculate new MTU, and create corresponding 769 * route (traditional PMTUD). 770 */ 771 tp->t_flags &= ~TF_PMTUD_PEND; 772 icmp_mtudisc(icp, inp->inp_rtableid); 773 } else { 774 /* 775 * Record the information got in the ICMP 776 * message; act on it later. 777 * If we had already recorded an ICMP message, 778 * replace the old one only if the new message 779 * refers to an older TCP segment 780 */ 781 if (tp->t_flags & TF_PMTUD_PEND) { 782 if (SEQ_LT(tp->t_pmtud_th_seq, seq)) { 783 in_pcbunref(inp); 784 return; 785 } 786 } else 787 tp->t_flags |= TF_PMTUD_PEND; 788 tp->t_pmtud_th_seq = seq; 789 tp->t_pmtud_nextmtu = icp->icmp_nextmtu; 790 tp->t_pmtud_ip_len = icp->icmp_ip.ip_len; 791 tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl; 792 in_pcbunref(inp); 793 return; 794 } 795 } else { 796 /* ignore if we don't have a matching connection */ 797 in_pcbunref(inp); 798 return; 799 } 800 in_pcbunref(inp); 801 notify = tcp_mtudisc, ip = 0; 802 } else if (cmd == PRC_MTUINC) 803 notify = tcp_mtudisc_increase, ip = 0; 804 else if (cmd == PRC_HOSTDEAD) 805 ip = 0; 806 else if (errno == 0) 807 return; 808 809 if (ip) { 810 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 811 inp = in_pcblookup(&tcbtable, 812 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 813 rdomain); 814 if (inp) { 815 seq = ntohl(th->th_seq); 816 if ((tp = intotcpcb(inp)) && 817 SEQ_GEQ(seq, tp->snd_una) && 818 SEQ_LT(seq, tp->snd_max)) 819 notify(inp, errno); 820 } else if (inetctlerrmap[cmd] == EHOSTUNREACH || 821 inetctlerrmap[cmd] == ENETUNREACH || 822 inetctlerrmap[cmd] == EHOSTDOWN) { 823 struct sockaddr_in sin; 824 825 bzero(&sin, sizeof(sin)); 826 sin.sin_len = sizeof(sin); 827 sin.sin_family = AF_INET; 828 sin.sin_port = th->th_sport; 829 sin.sin_addr = ip->ip_src; 830 syn_cache_unreach(sintosa(&sin), sa, th, rdomain); 831 } 832 in_pcbunref(inp); 833 } else 834 in_pcbnotifyall(&tcbtable, satosin(sa), rdomain, errno, notify); 835} 836 837 838#ifdef INET6 839/* 840 * Path MTU Discovery handlers. 841 */ 842void 843tcp6_mtudisc_callback(struct sockaddr_in6 *sin6, u_int rdomain) 844{ 845 in6_pcbnotify(&tcb6table, sin6, 0, 846 &sa6_any, 0, rdomain, PRC_MSGSIZE, NULL, tcp_mtudisc); 847} 848#endif /* INET6 */ 849 850/* 851 * On receipt of path MTU corrections, flush old route and replace it 852 * with the new one. Retransmit all unacknowledged packets, to ensure 853 * that all packets will be received. 854 */ 855void 856tcp_mtudisc(struct inpcb *inp, int errno) 857{ 858 struct tcpcb *tp = intotcpcb(inp); 859 struct rtentry *rt; 860 int orig_maxseg, change = 0; 861 862 if (tp == NULL) 863 return; 864 orig_maxseg = tp->t_maxseg; 865 866 rt = in_pcbrtentry(inp); 867 if (rt != NULL) { 868 unsigned int orig_mtulock = (rt->rt_locks & RTV_MTU); 869 870 /* 871 * If this was not a host route, remove and realloc. 872 */ 873 if ((rt->rt_flags & RTF_HOST) == 0) { 874 in_rtchange(inp, errno); 875 if ((rt = in_pcbrtentry(inp)) == NULL) 876 return; 877 } 878 if (orig_mtulock < (rt->rt_locks & RTV_MTU)) 879 change = 1; 880 } 881 tcp_mss(tp, -1); 882 if (orig_maxseg > tp->t_maxseg) 883 change = 1; 884 885 /* 886 * Resend unacknowledged packets 887 */ 888 tp->snd_nxt = tp->snd_una; 889 if (change || errno > 0) 890 tcp_output(tp); 891} 892 893void 894tcp_mtudisc_increase(struct inpcb *inp, int errno) 895{ 896 struct tcpcb *tp = intotcpcb(inp); 897 struct rtentry *rt = in_pcbrtentry(inp); 898 899 if (tp != 0 && rt != 0) { 900 /* 901 * If this was a host route, remove and realloc. 902 */ 903 if (rt->rt_flags & RTF_HOST) 904 in_rtchange(inp, errno); 905 906 /* also takes care of congestion window */ 907 tcp_mss(tp, -1); 908 } 909} 910 911/* 912 * Generate new ISNs with a method based on RFC1948 913 */ 914#define TCP_ISS_CONN_INC 4096 915 916void 917tcp_set_iss_tsm(struct tcpcb *tp) 918{ 919 SHA2_CTX ctx; 920 union { 921 uint8_t bytes[SHA512_DIGEST_LENGTH]; 922 uint32_t words[2]; 923 } digest; 924 u_int rdomain = rtable_l2(tp->t_inpcb->inp_rtableid); 925 tcp_seq iss; 926 927 mtx_enter(&tcp_timer_mtx); 928 tcp_iss += TCP_ISS_CONN_INC; 929 iss = tcp_iss; 930 mtx_leave(&tcp_timer_mtx); 931 932 ctx = tcp_secret_ctx; 933 SHA512Update(&ctx, &rdomain, sizeof(rdomain)); 934 SHA512Update(&ctx, &tp->t_inpcb->inp_lport, sizeof(u_short)); 935 SHA512Update(&ctx, &tp->t_inpcb->inp_fport, sizeof(u_short)); 936 if (tp->pf == AF_INET6) { 937 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr6, 938 sizeof(struct in6_addr)); 939 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr6, 940 sizeof(struct in6_addr)); 941 } else { 942 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr, 943 sizeof(struct in_addr)); 944 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr, 945 sizeof(struct in_addr)); 946 } 947 SHA512Final(digest.bytes, &ctx); 948 tp->iss = digest.words[0] + iss; 949 tp->ts_modulate = digest.words[1]; 950} 951 952#ifdef TCP_SIGNATURE 953int 954tcp_signature_tdb_attach(void) 955{ 956 return (0); 957} 958 959int 960tcp_signature_tdb_init(struct tdb *tdbp, const struct xformsw *xsp, 961 struct ipsecinit *ii) 962{ 963 if ((ii->ii_authkeylen < 1) || (ii->ii_authkeylen > 80)) 964 return (EINVAL); 965 966 tdbp->tdb_amxkey = malloc(ii->ii_authkeylen, M_XDATA, M_NOWAIT); 967 if (tdbp->tdb_amxkey == NULL) 968 return (ENOMEM); 969 memcpy(tdbp->tdb_amxkey, ii->ii_authkey, ii->ii_authkeylen); 970 tdbp->tdb_amxkeylen = ii->ii_authkeylen; 971 972 return (0); 973} 974 975int 976tcp_signature_tdb_zeroize(struct tdb *tdbp) 977{ 978 if (tdbp->tdb_amxkey) { 979 explicit_bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); 980 free(tdbp->tdb_amxkey, M_XDATA, tdbp->tdb_amxkeylen); 981 tdbp->tdb_amxkey = NULL; 982 } 983 984 return (0); 985} 986 987int 988tcp_signature_tdb_input(struct mbuf **mp, struct tdb *tdbp, int skip, 989 int protoff) 990{ 991 m_freemp(mp); 992 return (IPPROTO_DONE); 993} 994 995int 996tcp_signature_tdb_output(struct mbuf *m, struct tdb *tdbp, int skip, 997 int protoff) 998{ 999 m_freem(m); 1000 return (EINVAL); 1001} 1002 1003int 1004tcp_signature_apply(caddr_t fstate, caddr_t data, unsigned int len) 1005{ 1006 MD5Update((MD5_CTX *)fstate, (char *)data, len); 1007 return 0; 1008} 1009 1010int 1011tcp_signature(struct tdb *tdb, int af, struct mbuf *m, struct tcphdr *th, 1012 int iphlen, int doswap, char *sig) 1013{ 1014 MD5_CTX ctx; 1015 int len; 1016 struct tcphdr th0; 1017 1018 MD5Init(&ctx); 1019 1020 switch(af) { 1021 case 0: 1022 case AF_INET: { 1023 struct ippseudo ippseudo; 1024 struct ip *ip; 1025 1026 ip = mtod(m, struct ip *); 1027 1028 ippseudo.ippseudo_src = ip->ip_src; 1029 ippseudo.ippseudo_dst = ip->ip_dst; 1030 ippseudo.ippseudo_pad = 0; 1031 ippseudo.ippseudo_p = IPPROTO_TCP; 1032 ippseudo.ippseudo_len = htons(m->m_pkthdr.len - iphlen); 1033 1034 MD5Update(&ctx, (char *)&ippseudo, 1035 sizeof(struct ippseudo)); 1036 break; 1037 } 1038#ifdef INET6 1039 case AF_INET6: { 1040 struct ip6_hdr_pseudo ip6pseudo; 1041 struct ip6_hdr *ip6; 1042 1043 ip6 = mtod(m, struct ip6_hdr *); 1044 bzero(&ip6pseudo, sizeof(ip6pseudo)); 1045 ip6pseudo.ip6ph_src = ip6->ip6_src; 1046 ip6pseudo.ip6ph_dst = ip6->ip6_dst; 1047 in6_clearscope(&ip6pseudo.ip6ph_src); 1048 in6_clearscope(&ip6pseudo.ip6ph_dst); 1049 ip6pseudo.ip6ph_nxt = IPPROTO_TCP; 1050 ip6pseudo.ip6ph_len = htonl(m->m_pkthdr.len - iphlen); 1051 1052 MD5Update(&ctx, (char *)&ip6pseudo, 1053 sizeof(ip6pseudo)); 1054 break; 1055 } 1056#endif 1057 } 1058 1059 th0 = *th; 1060 th0.th_sum = 0; 1061 1062 if (doswap) { 1063 th0.th_seq = htonl(th0.th_seq); 1064 th0.th_ack = htonl(th0.th_ack); 1065 th0.th_win = htons(th0.th_win); 1066 th0.th_urp = htons(th0.th_urp); 1067 } 1068 MD5Update(&ctx, (char *)&th0, sizeof(th0)); 1069 1070 len = m->m_pkthdr.len - iphlen - th->th_off * sizeof(uint32_t); 1071 1072 if (len > 0 && 1073 m_apply(m, iphlen + th->th_off * sizeof(uint32_t), len, 1074 tcp_signature_apply, (caddr_t)&ctx)) 1075 return (-1); 1076 1077 MD5Update(&ctx, tdb->tdb_amxkey, tdb->tdb_amxkeylen); 1078 MD5Final(sig, &ctx); 1079 1080 return (0); 1081} 1082#endif /* TCP_SIGNATURE */ 1083