1 /* $OpenBSD: tcp_subr.c,v 1.151 2016/03/07 18:44:00 naddy 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/socket.h> 75 #include <sys/socketvar.h> 76 #include <sys/timeout.h> 77 #include <sys/protosw.h> 78 #include <sys/kernel.h> 79 #include <sys/pool.h> 80 81 #include <net/route.h> 82 83 #include <netinet/in.h> 84 #include <netinet/ip.h> 85 #include <netinet/in_pcb.h> 86 #include <netinet/ip_var.h> 87 #include <netinet/ip_icmp.h> 88 #include <netinet/tcp.h> 89 #include <netinet/tcp_fsm.h> 90 #include <netinet/tcp_seq.h> 91 #include <netinet/tcp_timer.h> 92 #include <netinet/tcp_var.h> 93 #include <netinet/tcpip.h> 94 95 #ifdef INET6 96 #include <netinet6/ip6protosw.h> 97 #endif /* INET6 */ 98 99 #include <crypto/md5.h> 100 #include <crypto/sha2.h> 101 102 /* patchable/settable parameters for tcp */ 103 int tcp_mssdflt = TCP_MSS; 104 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 105 106 /* values controllable via sysctl */ 107 int tcp_do_rfc1323 = 1; 108 #ifdef TCP_SACK 109 int tcp_do_sack = 1; /* RFC 2018 selective ACKs */ 110 #endif 111 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ 112 #ifdef TCP_ECN 113 int tcp_do_ecn = 0; /* RFC3168 ECN enabled/disabled? */ 114 #endif 115 int tcp_do_rfc3390 = 2; /* Increase TCP's Initial Window to 10*mss */ 116 117 u_int32_t tcp_now = 1; 118 119 #ifndef TCB_INITIAL_HASH_SIZE 120 #define TCB_INITIAL_HASH_SIZE 128 121 #endif 122 123 int tcp_reass_limit = NMBCLUSTERS / 2; /* hardlimit for tcpqe_pool */ 124 #ifdef TCP_SACK 125 int tcp_sackhole_limit = 32*1024; /* hardlimit for sackhl_pool */ 126 #endif 127 128 struct pool tcpcb_pool; 129 struct pool tcpqe_pool; 130 #ifdef TCP_SACK 131 struct pool sackhl_pool; 132 #endif 133 134 struct tcpstat tcpstat; /* tcp statistics */ 135 tcp_seq tcp_iss; 136 137 /* 138 * Tcp initialization 139 */ 140 void 141 tcp_init(void) 142 { 143 tcp_iss = 1; /* wrong */ 144 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcb", NULL); 145 pool_init(&tcpqe_pool, sizeof(struct tcpqent), 0, 0, 0, "tcpqe", NULL); 146 pool_sethardlimit(&tcpqe_pool, tcp_reass_limit, NULL, 0); 147 #ifdef TCP_SACK 148 pool_init(&sackhl_pool, sizeof(struct sackhole), 0, 0, 0, "sackhl", 149 NULL); 150 pool_sethardlimit(&sackhl_pool, tcp_sackhole_limit, NULL, 0); 151 #endif /* TCP_SACK */ 152 in_pcbinit(&tcbtable, TCB_INITIAL_HASH_SIZE); 153 154 #ifdef INET6 155 /* 156 * Since sizeof(struct ip6_hdr) > sizeof(struct ip), we 157 * do max length checks/computations only on the former. 158 */ 159 if (max_protohdr < (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))) 160 max_protohdr = (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)); 161 if ((max_linkhdr + sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) > 162 MHLEN) 163 panic("tcp_init"); 164 165 icmp6_mtudisc_callback_register(tcp6_mtudisc_callback); 166 #endif /* INET6 */ 167 168 /* Initialize the compressed state engine. */ 169 syn_cache_init(); 170 171 /* Initialize timer state. */ 172 tcp_timer_init(); 173 } 174 175 /* 176 * Create template to be used to send tcp packets on a connection. 177 * Call after host entry created, allocates an mbuf and fills 178 * in a skeletal tcp/ip header, minimizing the amount of work 179 * necessary when the connection is used. 180 * 181 * To support IPv6 in addition to IPv4 and considering that the sizes of 182 * the IPv4 and IPv6 headers are not the same, we now use a separate pointer 183 * for the TCP header. Also, we made the former tcpiphdr header pointer 184 * into just an IP overlay pointer, with casting as appropriate for v6. rja 185 */ 186 struct mbuf * 187 tcp_template(tp) 188 struct tcpcb *tp; 189 { 190 struct inpcb *inp = tp->t_inpcb; 191 struct mbuf *m; 192 struct tcphdr *th; 193 194 if ((m = tp->t_template) == 0) { 195 m = m_get(M_DONTWAIT, MT_HEADER); 196 if (m == NULL) 197 return (0); 198 199 switch (tp->pf) { 200 case 0: /*default to PF_INET*/ 201 case AF_INET: 202 m->m_len = sizeof(struct ip); 203 break; 204 #ifdef INET6 205 case AF_INET6: 206 m->m_len = sizeof(struct ip6_hdr); 207 break; 208 #endif /* INET6 */ 209 } 210 m->m_len += sizeof (struct tcphdr); 211 212 /* 213 * The link header, network header, TCP header, and TCP options 214 * all must fit in this mbuf. For now, assume the worst case of 215 * TCP options size. Eventually, compute this from tp flags. 216 */ 217 if (m->m_len + MAX_TCPOPTLEN + max_linkhdr >= MHLEN) { 218 MCLGET(m, M_DONTWAIT); 219 if ((m->m_flags & M_EXT) == 0) { 220 m_free(m); 221 return (0); 222 } 223 } 224 } 225 226 switch(tp->pf) { 227 case AF_INET: 228 { 229 struct ipovly *ipovly; 230 231 ipovly = mtod(m, struct ipovly *); 232 233 bzero(ipovly->ih_x1, sizeof ipovly->ih_x1); 234 ipovly->ih_pr = IPPROTO_TCP; 235 ipovly->ih_len = htons(sizeof (struct tcphdr)); 236 ipovly->ih_src = inp->inp_laddr; 237 ipovly->ih_dst = inp->inp_faddr; 238 239 th = (struct tcphdr *)(mtod(m, caddr_t) + 240 sizeof(struct ip)); 241 } 242 break; 243 #ifdef INET6 244 case AF_INET6: 245 { 246 struct ip6_hdr *ip6; 247 248 ip6 = mtod(m, struct ip6_hdr *); 249 250 ip6->ip6_src = inp->inp_laddr6; 251 ip6->ip6_dst = inp->inp_faddr6; 252 ip6->ip6_flow = htonl(0x60000000) | 253 (inp->inp_flowinfo & IPV6_FLOWLABEL_MASK); 254 255 ip6->ip6_nxt = IPPROTO_TCP; 256 ip6->ip6_plen = htons(sizeof(struct tcphdr)); /*XXX*/ 257 ip6->ip6_hlim = in6_selecthlim(inp); /*XXX*/ 258 259 th = (struct tcphdr *)(mtod(m, caddr_t) + 260 sizeof(struct ip6_hdr)); 261 } 262 break; 263 #endif /* INET6 */ 264 } 265 266 th->th_sport = inp->inp_lport; 267 th->th_dport = inp->inp_fport; 268 th->th_seq = 0; 269 th->th_ack = 0; 270 th->th_x2 = 0; 271 th->th_off = 5; 272 th->th_flags = 0; 273 th->th_win = 0; 274 th->th_urp = 0; 275 th->th_sum = 0; 276 return (m); 277 } 278 279 /* 280 * Send a single message to the TCP at address specified by 281 * the given TCP/IP header. If m == 0, then we make a copy 282 * of the tcpiphdr at ti and send directly to the addressed host. 283 * This is used to force keep alive messages out using the TCP 284 * template for a connection tp->t_template. If flags are given 285 * then we send a message back to the TCP which originated the 286 * segment ti, and discard the mbuf containing it and any other 287 * attached mbufs. 288 * 289 * In any case the ack and sequence number of the transmitted 290 * segment are as specified by the parameters. 291 */ 292 void 293 tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0, 294 tcp_seq ack, tcp_seq seq, int flags, u_int rtableid) 295 { 296 int tlen; 297 int win = 0; 298 struct mbuf *m = NULL; 299 struct route *ro = NULL; 300 struct tcphdr *th; 301 struct ip *ip; 302 #ifdef INET6 303 struct ip6_hdr *ip6; 304 #endif 305 int af; /* af on wire */ 306 307 if (tp) { 308 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 309 /* 310 * If this is called with an unconnected 311 * socket/tp/pcb (tp->pf is 0), we lose. 312 */ 313 af = tp->pf; 314 315 /* 316 * The route/route6 distinction is meaningless 317 * unless you're allocating space or passing parameters. 318 */ 319 ro = &tp->t_inpcb->inp_route; 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(tcp_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 (struct route_in6 *)ro, 0, NULL, 408 tp ? tp->t_inpcb : NULL); 409 break; 410 #endif /* INET6 */ 411 case AF_INET: 412 ip->ip_len = htons(tlen); 413 ip->ip_ttl = ip_defttl; 414 ip->ip_tos = 0; 415 ip_output(m, NULL, ro, ip_mtudisc ? IP_MTUDISC : 0, 416 NULL, tp ? tp->t_inpcb : NULL, 0); 417 } 418 } 419 420 /* 421 * Create a new TCP control block, making an 422 * empty reassembly queue and hooking it to the argument 423 * protocol control block. 424 */ 425 struct tcpcb * 426 tcp_newtcpcb(struct inpcb *inp) 427 { 428 struct tcpcb *tp; 429 int i; 430 431 tp = pool_get(&tcpcb_pool, PR_NOWAIT|PR_ZERO); 432 if (tp == NULL) 433 return (NULL); 434 TAILQ_INIT(&tp->t_segq); 435 tp->t_maxseg = tcp_mssdflt; 436 tp->t_maxopd = 0; 437 438 TCP_INIT_DELACK(tp); 439 for (i = 0; i < TCPT_NTIMERS; i++) 440 TCP_TIMER_INIT(tp, i); 441 timeout_set(&tp->t_reap_to, tcp_reaper, tp); 442 443 #ifdef TCP_SACK 444 tp->sack_enable = tcp_do_sack; 445 #endif 446 tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; 447 tp->t_inpcb = inp; 448 /* 449 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 450 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 451 * reasonable initial retransmit time. 452 */ 453 tp->t_srtt = TCPTV_SRTTBASE; 454 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << 455 (TCP_RTTVAR_SHIFT + TCP_RTT_BASE_SHIFT - 1); 456 tp->t_rttmin = TCPTV_MIN; 457 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 458 TCPTV_MIN, TCPTV_REXMTMAX); 459 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 460 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 461 462 tp->t_pmtud_mtu_sent = 0; 463 tp->t_pmtud_mss_acked = 0; 464 465 #ifdef INET6 466 /* we disallow IPv4 mapped address completely. */ 467 if ((inp->inp_flags & INP_IPV6) == 0) 468 tp->pf = PF_INET; 469 else 470 tp->pf = PF_INET6; 471 #else 472 tp->pf = PF_INET; 473 #endif 474 475 #ifdef INET6 476 if (inp->inp_flags & INP_IPV6) 477 inp->inp_ipv6.ip6_hlim = ip6_defhlim; 478 else 479 #endif /* INET6 */ 480 inp->inp_ip.ip_ttl = ip_defttl; 481 482 inp->inp_ppcb = (caddr_t)tp; 483 return (tp); 484 } 485 486 /* 487 * Drop a TCP connection, reporting 488 * the specified error. If connection is synchronized, 489 * then send a RST to peer. 490 */ 491 struct tcpcb * 492 tcp_drop(tp, errno) 493 struct tcpcb *tp; 494 int errno; 495 { 496 struct socket *so = tp->t_inpcb->inp_socket; 497 498 if (TCPS_HAVERCVDSYN(tp->t_state)) { 499 tp->t_state = TCPS_CLOSED; 500 (void) tcp_output(tp); 501 tcpstat.tcps_drops++; 502 } else 503 tcpstat.tcps_conndrops++; 504 if (errno == ETIMEDOUT && tp->t_softerror) 505 errno = tp->t_softerror; 506 so->so_error = errno; 507 return (tcp_close(tp)); 508 } 509 510 /* 511 * Close a TCP control block: 512 * discard all space held by the tcp 513 * discard internet protocol block 514 * wake up any sleepers 515 */ 516 struct tcpcb * 517 tcp_close(struct tcpcb *tp) 518 { 519 struct inpcb *inp = tp->t_inpcb; 520 struct socket *so = inp->inp_socket; 521 #ifdef TCP_SACK 522 struct sackhole *p, *q; 523 #endif 524 525 /* free the reassembly queue, if any */ 526 tcp_freeq(tp); 527 528 tcp_canceltimers(tp); 529 TCP_CLEAR_DELACK(tp); 530 syn_cache_cleanup(tp); 531 532 #ifdef TCP_SACK 533 /* Free SACK holes. */ 534 q = p = tp->snd_holes; 535 while (p != 0) { 536 q = p->next; 537 pool_put(&sackhl_pool, p); 538 p = q; 539 } 540 #endif 541 if (tp->t_template) 542 (void) m_free(tp->t_template); 543 544 tp->t_flags |= TF_DEAD; 545 timeout_add(&tp->t_reap_to, 0); 546 547 inp->inp_ppcb = 0; 548 soisdisconnected(so); 549 in_pcbdetach(inp); 550 return (NULL); 551 } 552 553 void 554 tcp_reaper(void *arg) 555 { 556 struct tcpcb *tp = arg; 557 int s; 558 559 s = splsoftnet(); 560 pool_put(&tcpcb_pool, tp); 561 splx(s); 562 tcpstat.tcps_closed++; 563 } 564 565 int 566 tcp_freeq(struct tcpcb *tp) 567 { 568 struct tcpqent *qe; 569 int rv = 0; 570 571 while ((qe = TAILQ_FIRST(&tp->t_segq)) != NULL) { 572 TAILQ_REMOVE(&tp->t_segq, qe, tcpqe_q); 573 m_freem(qe->tcpqe_m); 574 pool_put(&tcpqe_pool, qe); 575 rv = 1; 576 } 577 return (rv); 578 } 579 580 /* 581 * Compute proper scaling value for receiver window from buffer space 582 */ 583 584 void 585 tcp_rscale(struct tcpcb *tp, u_long hiwat) 586 { 587 tp->request_r_scale = 0; 588 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 589 TCP_MAXWIN << tp->request_r_scale < hiwat) 590 tp->request_r_scale++; 591 } 592 593 /* 594 * Notify a tcp user of an asynchronous error; 595 * store error as soft error, but wake up user 596 * (for now, won't do anything until can select for soft error). 597 */ 598 void 599 tcp_notify(inp, error) 600 struct inpcb *inp; 601 int error; 602 { 603 struct tcpcb *tp = intotcpcb(inp); 604 struct socket *so = inp->inp_socket; 605 606 /* 607 * Ignore some errors if we are hooked up. 608 * If connection hasn't completed, has retransmitted several times, 609 * and receives a second error, give up now. This is better 610 * than waiting a long time to establish a connection that 611 * can never complete. 612 */ 613 if (tp->t_state == TCPS_ESTABLISHED && 614 (error == EHOSTUNREACH || error == ENETUNREACH || 615 error == EHOSTDOWN)) { 616 return; 617 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 618 tp->t_rxtshift > 3 && tp->t_softerror) 619 so->so_error = error; 620 else 621 tp->t_softerror = error; 622 wakeup((caddr_t) &so->so_timeo); 623 sorwakeup(so); 624 sowwakeup(so); 625 } 626 627 #ifdef INET6 628 void 629 tcp6_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *d) 630 { 631 struct tcphdr th; 632 struct tcpcb *tp; 633 void (*notify)(struct inpcb *, int) = tcp_notify; 634 struct ip6_hdr *ip6; 635 const struct sockaddr_in6 *sa6_src = NULL; 636 struct sockaddr_in6 *sa6 = satosin6(sa); 637 struct inpcb *inp; 638 struct mbuf *m; 639 tcp_seq seq; 640 int off; 641 struct { 642 u_int16_t th_sport; 643 u_int16_t th_dport; 644 u_int32_t th_seq; 645 } *thp; 646 647 if (sa->sa_family != AF_INET6 || 648 sa->sa_len != sizeof(struct sockaddr_in6) || 649 IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) || 650 IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) 651 return; 652 if ((unsigned)cmd >= PRC_NCMDS) 653 return; 654 else if (cmd == PRC_QUENCH) { 655 /* 656 * Don't honor ICMP Source Quench messages meant for 657 * TCP connections. 658 */ 659 /* XXX there's no PRC_QUENCH in IPv6 */ 660 return; 661 } else if (PRC_IS_REDIRECT(cmd)) 662 notify = in_rtchange, d = NULL; 663 else if (cmd == PRC_MSGSIZE) 664 ; /* special code is present, see below */ 665 else if (cmd == PRC_HOSTDEAD) 666 d = NULL; 667 else if (inet6ctlerrmap[cmd] == 0) 668 return; 669 670 /* if the parameter is from icmp6, decode it. */ 671 if (d != NULL) { 672 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 673 m = ip6cp->ip6c_m; 674 ip6 = ip6cp->ip6c_ip6; 675 off = ip6cp->ip6c_off; 676 sa6_src = ip6cp->ip6c_src; 677 } else { 678 m = NULL; 679 ip6 = NULL; 680 sa6_src = &sa6_any; 681 } 682 683 if (ip6) { 684 /* 685 * XXX: We assume that when ip6 is non NULL, 686 * M and OFF are valid. 687 */ 688 689 /* check if we can safely examine src and dst ports */ 690 if (m->m_pkthdr.len < off + sizeof(*thp)) 691 return; 692 693 bzero(&th, sizeof(th)); 694 #ifdef DIAGNOSTIC 695 if (sizeof(*thp) > sizeof(th)) 696 panic("assumption failed in tcp6_ctlinput"); 697 #endif 698 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 699 700 /* 701 * Check to see if we have a valid TCP connection 702 * corresponding to the address in the ICMPv6 message 703 * payload. 704 */ 705 inp = in6_pcbhashlookup(&tcbtable, &sa6->sin6_addr, 706 th.th_dport, (struct in6_addr *)&sa6_src->sin6_addr, 707 th.th_sport, rdomain); 708 if (cmd == PRC_MSGSIZE) { 709 /* 710 * Depending on the value of "valid" and routing table 711 * size (mtudisc_{hi,lo}wat), we will: 712 * - recalcurate the new MTU and create the 713 * corresponding routing entry, or 714 * - ignore the MTU change notification. 715 */ 716 icmp6_mtudisc_update((struct ip6ctlparam *)d, inp != NULL); 717 return; 718 } 719 if (inp) { 720 seq = ntohl(th.th_seq); 721 if (inp->inp_socket && 722 (tp = intotcpcb(inp)) && 723 SEQ_GEQ(seq, tp->snd_una) && 724 SEQ_LT(seq, tp->snd_max)) 725 notify(inp, inet6ctlerrmap[cmd]); 726 } else if (inet6ctlerrmap[cmd] == EHOSTUNREACH || 727 inet6ctlerrmap[cmd] == ENETUNREACH || 728 inet6ctlerrmap[cmd] == EHOSTDOWN) 729 syn_cache_unreach((struct sockaddr *)sa6_src, 730 sa, &th, rdomain); 731 } else { 732 (void) in6_pcbnotify(&tcbtable, sa6, 0, 733 sa6_src, 0, rdomain, cmd, NULL, notify); 734 } 735 } 736 #endif 737 738 void * 739 tcp_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *v) 740 { 741 struct ip *ip = v; 742 struct tcphdr *th; 743 struct tcpcb *tp; 744 struct inpcb *inp; 745 struct in_addr faddr; 746 tcp_seq seq; 747 u_int mtu; 748 void (*notify)(struct inpcb *, int) = tcp_notify; 749 int errno; 750 751 if (sa->sa_family != AF_INET) 752 return NULL; 753 faddr = satosin(sa)->sin_addr; 754 if (faddr.s_addr == INADDR_ANY) 755 return NULL; 756 757 if ((unsigned)cmd >= PRC_NCMDS) 758 return NULL; 759 errno = inetctlerrmap[cmd]; 760 if (cmd == PRC_QUENCH) 761 /* 762 * Don't honor ICMP Source Quench messages meant for 763 * TCP connections. 764 */ 765 return NULL; 766 else if (PRC_IS_REDIRECT(cmd)) 767 notify = in_rtchange, ip = 0; 768 else if (cmd == PRC_MSGSIZE && ip_mtudisc && ip) { 769 /* 770 * Verify that the packet in the icmp payload refers 771 * to an existing TCP connection. 772 */ 773 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 774 seq = ntohl(th->th_seq); 775 inp = in_pcbhashlookup(&tcbtable, 776 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 777 rdomain); 778 if (inp && (tp = intotcpcb(inp)) && 779 SEQ_GEQ(seq, tp->snd_una) && 780 SEQ_LT(seq, tp->snd_max)) { 781 struct icmp *icp; 782 icp = (struct icmp *)((caddr_t)ip - 783 offsetof(struct icmp, icmp_ip)); 784 785 /* 786 * If the ICMP message advertises a Next-Hop MTU 787 * equal or larger than the maximum packet size we have 788 * ever sent, drop the message. 789 */ 790 mtu = (u_int)ntohs(icp->icmp_nextmtu); 791 if (mtu >= tp->t_pmtud_mtu_sent) 792 return NULL; 793 if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) { 794 /* 795 * Calculate new MTU, and create corresponding 796 * route (traditional PMTUD). 797 */ 798 tp->t_flags &= ~TF_PMTUD_PEND; 799 icmp_mtudisc(icp, inp->inp_rtableid); 800 } else { 801 /* 802 * Record the information got in the ICMP 803 * message; act on it later. 804 * If we had already recorded an ICMP message, 805 * replace the old one only if the new message 806 * refers to an older TCP segment 807 */ 808 if (tp->t_flags & TF_PMTUD_PEND) { 809 if (SEQ_LT(tp->t_pmtud_th_seq, seq)) 810 return NULL; 811 } else 812 tp->t_flags |= TF_PMTUD_PEND; 813 tp->t_pmtud_th_seq = seq; 814 tp->t_pmtud_nextmtu = icp->icmp_nextmtu; 815 tp->t_pmtud_ip_len = icp->icmp_ip.ip_len; 816 tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl; 817 return NULL; 818 } 819 } else { 820 /* ignore if we don't have a matching connection */ 821 return NULL; 822 } 823 notify = tcp_mtudisc, ip = 0; 824 } else if (cmd == PRC_MTUINC) 825 notify = tcp_mtudisc_increase, ip = 0; 826 else if (cmd == PRC_HOSTDEAD) 827 ip = 0; 828 else if (errno == 0) 829 return NULL; 830 831 if (ip) { 832 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 833 inp = in_pcbhashlookup(&tcbtable, 834 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 835 rdomain); 836 if (inp) { 837 seq = ntohl(th->th_seq); 838 if (inp->inp_socket && 839 (tp = intotcpcb(inp)) && 840 SEQ_GEQ(seq, tp->snd_una) && 841 SEQ_LT(seq, tp->snd_max)) 842 notify(inp, errno); 843 } else if (inetctlerrmap[cmd] == EHOSTUNREACH || 844 inetctlerrmap[cmd] == ENETUNREACH || 845 inetctlerrmap[cmd] == EHOSTDOWN) { 846 struct sockaddr_in sin; 847 848 bzero(&sin, sizeof(sin)); 849 sin.sin_len = sizeof(sin); 850 sin.sin_family = AF_INET; 851 sin.sin_port = th->th_sport; 852 sin.sin_addr = ip->ip_src; 853 syn_cache_unreach(sintosa(&sin), sa, th, rdomain); 854 } 855 } else 856 in_pcbnotifyall(&tcbtable, sa, rdomain, errno, notify); 857 858 return NULL; 859 } 860 861 862 #ifdef INET6 863 /* 864 * Path MTU Discovery handlers. 865 */ 866 void 867 tcp6_mtudisc_callback(sin6, rdomain) 868 struct sockaddr_in6 *sin6; 869 u_int rdomain; 870 { 871 (void) in6_pcbnotify(&tcbtable, sin6, 0, 872 &sa6_any, 0, rdomain, PRC_MSGSIZE, NULL, tcp_mtudisc); 873 } 874 #endif /* INET6 */ 875 876 /* 877 * On receipt of path MTU corrections, flush old route and replace it 878 * with the new one. Retransmit all unacknowledged packets, to ensure 879 * that all packets will be received. 880 */ 881 void 882 tcp_mtudisc(inp, errno) 883 struct inpcb *inp; 884 int errno; 885 { 886 struct tcpcb *tp = intotcpcb(inp); 887 struct rtentry *rt = in_pcbrtentry(inp); 888 int change = 0; 889 890 if (tp != 0) { 891 int orig_maxseg = tp->t_maxseg; 892 if (rt != 0) { 893 /* 894 * If this was not a host route, remove and realloc. 895 */ 896 if ((rt->rt_flags & RTF_HOST) == 0) { 897 in_rtchange(inp, errno); 898 if ((rt = in_pcbrtentry(inp)) == 0) 899 return; 900 } 901 if (orig_maxseg != tp->t_maxseg || 902 (rt->rt_rmx.rmx_locks & RTV_MTU)) 903 change = 1; 904 } 905 tcp_mss(tp, -1); 906 907 /* 908 * Resend unacknowledged packets 909 */ 910 tp->snd_nxt = tp->snd_una; 911 if (change || errno > 0) 912 tcp_output(tp); 913 } 914 } 915 916 void 917 tcp_mtudisc_increase(inp, errno) 918 struct inpcb *inp; 919 int errno; 920 { 921 struct tcpcb *tp = intotcpcb(inp); 922 struct rtentry *rt = in_pcbrtentry(inp); 923 924 if (tp != 0 && rt != 0) { 925 /* 926 * If this was a host route, remove and realloc. 927 */ 928 if (rt->rt_flags & RTF_HOST) 929 in_rtchange(inp, errno); 930 931 /* also takes care of congestion window */ 932 tcp_mss(tp, -1); 933 } 934 } 935 936 /* 937 * Generate new ISNs with a method based on RFC1948 938 */ 939 #define TCP_ISS_CONN_INC 4096 940 int tcp_secret_init; 941 u_char tcp_secret[16]; 942 SHA2_CTX tcp_secret_ctx; 943 944 void 945 tcp_set_iss_tsm(struct tcpcb *tp) 946 { 947 SHA2_CTX ctx; 948 union { 949 uint8_t bytes[SHA512_DIGEST_LENGTH]; 950 uint32_t words[2]; 951 } digest; 952 u_int rdomain = rtable_l2(tp->t_inpcb->inp_rtableid); 953 954 if (tcp_secret_init == 0) { 955 arc4random_buf(tcp_secret, sizeof(tcp_secret)); 956 SHA512Init(&tcp_secret_ctx); 957 SHA512Update(&tcp_secret_ctx, tcp_secret, sizeof(tcp_secret)); 958 tcp_secret_init = 1; 959 } 960 ctx = tcp_secret_ctx; 961 SHA512Update(&ctx, &rdomain, sizeof(rdomain)); 962 SHA512Update(&ctx, &tp->t_inpcb->inp_lport, sizeof(u_short)); 963 SHA512Update(&ctx, &tp->t_inpcb->inp_fport, sizeof(u_short)); 964 if (tp->pf == AF_INET6) { 965 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr6, 966 sizeof(struct in6_addr)); 967 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr6, 968 sizeof(struct in6_addr)); 969 } else { 970 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr, 971 sizeof(struct in_addr)); 972 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr, 973 sizeof(struct in_addr)); 974 } 975 SHA512Final(digest.bytes, &ctx); 976 tcp_iss += TCP_ISS_CONN_INC; 977 tp->iss = digest.words[0] + tcp_iss; 978 tp->ts_modulate = digest.words[1]; 979 } 980 981 #ifdef TCP_SIGNATURE 982 int 983 tcp_signature_tdb_attach(void) 984 { 985 return (0); 986 } 987 988 int 989 tcp_signature_tdb_init(tdbp, xsp, ii) 990 struct tdb *tdbp; 991 struct xformsw *xsp; 992 struct ipsecinit *ii; 993 { 994 if ((ii->ii_authkeylen < 1) || (ii->ii_authkeylen > 80)) 995 return (EINVAL); 996 997 tdbp->tdb_amxkey = malloc(ii->ii_authkeylen, M_XDATA, M_NOWAIT); 998 if (tdbp->tdb_amxkey == NULL) 999 return (ENOMEM); 1000 bcopy(ii->ii_authkey, tdbp->tdb_amxkey, ii->ii_authkeylen); 1001 tdbp->tdb_amxkeylen = ii->ii_authkeylen; 1002 1003 return (0); 1004 } 1005 1006 int 1007 tcp_signature_tdb_zeroize(tdbp) 1008 struct tdb *tdbp; 1009 { 1010 if (tdbp->tdb_amxkey) { 1011 explicit_bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); 1012 free(tdbp->tdb_amxkey, M_XDATA, 0); 1013 tdbp->tdb_amxkey = NULL; 1014 } 1015 1016 return (0); 1017 } 1018 1019 int 1020 tcp_signature_tdb_input(m, tdbp, skip, protoff) 1021 struct mbuf *m; 1022 struct tdb *tdbp; 1023 int skip, protoff; 1024 { 1025 return (0); 1026 } 1027 1028 int 1029 tcp_signature_tdb_output(m, tdbp, mp, skip, protoff) 1030 struct mbuf *m; 1031 struct tdb *tdbp; 1032 struct mbuf **mp; 1033 int skip, protoff; 1034 { 1035 return (EINVAL); 1036 } 1037 1038 int 1039 tcp_signature_apply(fstate, data, len) 1040 caddr_t fstate; 1041 caddr_t data; 1042 unsigned int len; 1043 { 1044 MD5Update((MD5_CTX *)fstate, (char *)data, len); 1045 return 0; 1046 } 1047 1048 int 1049 tcp_signature(struct tdb *tdb, int af, struct mbuf *m, struct tcphdr *th, 1050 int iphlen, int doswap, char *sig) 1051 { 1052 MD5_CTX ctx; 1053 int len; 1054 struct tcphdr th0; 1055 1056 MD5Init(&ctx); 1057 1058 switch(af) { 1059 case 0: 1060 case AF_INET: { 1061 struct ippseudo ippseudo; 1062 struct ip *ip; 1063 1064 ip = mtod(m, struct ip *); 1065 1066 ippseudo.ippseudo_src = ip->ip_src; 1067 ippseudo.ippseudo_dst = ip->ip_dst; 1068 ippseudo.ippseudo_pad = 0; 1069 ippseudo.ippseudo_p = IPPROTO_TCP; 1070 ippseudo.ippseudo_len = htons(m->m_pkthdr.len - iphlen); 1071 1072 MD5Update(&ctx, (char *)&ippseudo, 1073 sizeof(struct ippseudo)); 1074 break; 1075 } 1076 #ifdef INET6 1077 case AF_INET6: { 1078 struct ip6_hdr_pseudo ip6pseudo; 1079 struct ip6_hdr *ip6; 1080 1081 ip6 = mtod(m, struct ip6_hdr *); 1082 bzero(&ip6pseudo, sizeof(ip6pseudo)); 1083 ip6pseudo.ip6ph_src = ip6->ip6_src; 1084 ip6pseudo.ip6ph_dst = ip6->ip6_dst; 1085 in6_clearscope(&ip6pseudo.ip6ph_src); 1086 in6_clearscope(&ip6pseudo.ip6ph_dst); 1087 ip6pseudo.ip6ph_nxt = IPPROTO_TCP; 1088 ip6pseudo.ip6ph_len = htonl(m->m_pkthdr.len - iphlen); 1089 1090 MD5Update(&ctx, (char *)&ip6pseudo, 1091 sizeof(ip6pseudo)); 1092 break; 1093 } 1094 #endif 1095 } 1096 1097 th0 = *th; 1098 th0.th_sum = 0; 1099 1100 if (doswap) { 1101 th0.th_seq = htonl(th0.th_seq); 1102 th0.th_ack = htonl(th0.th_ack); 1103 th0.th_win = htons(th0.th_win); 1104 th0.th_urp = htons(th0.th_urp); 1105 } 1106 MD5Update(&ctx, (char *)&th0, sizeof(th0)); 1107 1108 len = m->m_pkthdr.len - iphlen - th->th_off * sizeof(uint32_t); 1109 1110 if (len > 0 && 1111 m_apply(m, iphlen + th->th_off * sizeof(uint32_t), len, 1112 tcp_signature_apply, (caddr_t)&ctx)) 1113 return (-1); 1114 1115 MD5Update(&ctx, tdb->tdb_amxkey, tdb->tdb_amxkeylen); 1116 MD5Final(sig, &ctx); 1117 1118 return (0); 1119 } 1120 #endif /* TCP_SIGNATURE */ 1121