1 /* $OpenBSD: tcp_subr.c,v 1.158 2017/01/10 09:01:18 mpi 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 / 8; /* 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, IPL_SOFTNET, 0, 145 "tcpcb", NULL); 146 pool_init(&tcpqe_pool, sizeof(struct tcpqent), 0, IPL_SOFTNET, 0, 147 "tcpqe", NULL); 148 pool_sethardlimit(&tcpqe_pool, tcp_reass_limit, NULL, 0); 149 #ifdef TCP_SACK 150 pool_init(&sackhl_pool, sizeof(struct sackhole), 0, IPL_SOFTNET, 0, 151 "sackhl", NULL); 152 pool_sethardlimit(&sackhl_pool, tcp_sackhole_limit, NULL, 0); 153 #endif /* TCP_SACK */ 154 in_pcbinit(&tcbtable, TCB_INITIAL_HASH_SIZE); 155 156 #ifdef INET6 157 /* 158 * Since sizeof(struct ip6_hdr) > sizeof(struct ip), we 159 * do max length checks/computations only on the former. 160 */ 161 if (max_protohdr < (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))) 162 max_protohdr = (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)); 163 if ((max_linkhdr + sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) > 164 MHLEN) 165 panic("tcp_init"); 166 167 icmp6_mtudisc_callback_register(tcp6_mtudisc_callback); 168 #endif /* INET6 */ 169 170 /* Initialize the compressed state engine. */ 171 syn_cache_init(); 172 173 /* Initialize timer state. */ 174 tcp_timer_init(); 175 } 176 177 /* 178 * Create template to be used to send tcp packets on a connection. 179 * Call after host entry created, allocates an mbuf and fills 180 * in a skeletal tcp/ip header, minimizing the amount of work 181 * necessary when the connection is used. 182 * 183 * To support IPv6 in addition to IPv4 and considering that the sizes of 184 * the IPv4 and IPv6 headers are not the same, we now use a separate pointer 185 * for the TCP header. Also, we made the former tcpiphdr header pointer 186 * into just an IP overlay pointer, with casting as appropriate for v6. rja 187 */ 188 struct mbuf * 189 tcp_template(struct tcpcb *tp) 190 { 191 struct inpcb *inp = tp->t_inpcb; 192 struct mbuf *m; 193 struct tcphdr *th; 194 195 if ((m = tp->t_template) == 0) { 196 m = m_get(M_DONTWAIT, MT_HEADER); 197 if (m == NULL) 198 return (0); 199 200 switch (tp->pf) { 201 case 0: /*default to PF_INET*/ 202 case AF_INET: 203 m->m_len = sizeof(struct ip); 204 break; 205 #ifdef INET6 206 case AF_INET6: 207 m->m_len = sizeof(struct ip6_hdr); 208 break; 209 #endif /* INET6 */ 210 } 211 m->m_len += sizeof (struct tcphdr); 212 213 /* 214 * The link header, network header, TCP header, and TCP options 215 * all must fit in this mbuf. For now, assume the worst case of 216 * TCP options size. Eventually, compute this from tp flags. 217 */ 218 if (m->m_len + MAX_TCPOPTLEN + max_linkhdr >= MHLEN) { 219 MCLGET(m, M_DONTWAIT); 220 if ((m->m_flags & M_EXT) == 0) { 221 m_free(m); 222 return (0); 223 } 224 } 225 } 226 227 switch(tp->pf) { 228 case AF_INET: 229 { 230 struct ipovly *ipovly; 231 232 ipovly = mtod(m, struct ipovly *); 233 234 bzero(ipovly->ih_x1, sizeof ipovly->ih_x1); 235 ipovly->ih_pr = IPPROTO_TCP; 236 ipovly->ih_len = htons(sizeof (struct tcphdr)); 237 ipovly->ih_src = inp->inp_laddr; 238 ipovly->ih_dst = inp->inp_faddr; 239 240 th = (struct tcphdr *)(mtod(m, caddr_t) + 241 sizeof(struct ip)); 242 } 243 break; 244 #ifdef INET6 245 case AF_INET6: 246 { 247 struct ip6_hdr *ip6; 248 249 ip6 = mtod(m, struct ip6_hdr *); 250 251 ip6->ip6_src = inp->inp_laddr6; 252 ip6->ip6_dst = inp->inp_faddr6; 253 ip6->ip6_flow = htonl(0x60000000) | 254 (inp->inp_flowinfo & IPV6_FLOWLABEL_MASK); 255 256 ip6->ip6_nxt = IPPROTO_TCP; 257 ip6->ip6_plen = htons(sizeof(struct tcphdr)); /*XXX*/ 258 ip6->ip6_hlim = in6_selecthlim(inp); /*XXX*/ 259 260 th = (struct tcphdr *)(mtod(m, caddr_t) + 261 sizeof(struct ip6_hdr)); 262 } 263 break; 264 #endif /* INET6 */ 265 } 266 267 th->th_sport = inp->inp_lport; 268 th->th_dport = inp->inp_fport; 269 th->th_seq = 0; 270 th->th_ack = 0; 271 th->th_x2 = 0; 272 th->th_off = 5; 273 th->th_flags = 0; 274 th->th_win = 0; 275 th->th_urp = 0; 276 th->th_sum = 0; 277 return (m); 278 } 279 280 /* 281 * Send a single message to the TCP at address specified by 282 * the given TCP/IP header. If m == 0, then we make a copy 283 * of the tcpiphdr at ti and send directly to the addressed host. 284 * This is used to force keep alive messages out using the TCP 285 * template for a connection tp->t_template. If flags are given 286 * then we send a message back to the TCP which originated the 287 * segment ti, and discard the mbuf containing it and any other 288 * attached mbufs. 289 * 290 * In any case the ack and sequence number of the transmitted 291 * segment are as specified by the parameters. 292 */ 293 void 294 tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0, 295 tcp_seq ack, tcp_seq seq, int flags, u_int rtableid) 296 { 297 int tlen; 298 int win = 0; 299 struct mbuf *m = 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 } else 315 af = (((struct ip *)template)->ip_v == 6) ? AF_INET6 : AF_INET; 316 317 m = m_gethdr(M_DONTWAIT, MT_HEADER); 318 if (m == NULL) 319 return; 320 m->m_data += max_linkhdr; 321 tlen = 0; 322 323 #define xchg(a,b,type) do { type t; t=a; a=b; b=t; } while (0) 324 switch (af) { 325 #ifdef INET6 326 case AF_INET6: 327 ip6 = mtod(m, struct ip6_hdr *); 328 th = (struct tcphdr *)(ip6 + 1); 329 tlen = sizeof(*ip6) + sizeof(*th); 330 if (th0) { 331 bcopy(template, ip6, sizeof(*ip6)); 332 bcopy(th0, th, sizeof(*th)); 333 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 334 } else { 335 bcopy(template, ip6, tlen); 336 } 337 break; 338 #endif /* INET6 */ 339 case AF_INET: 340 ip = mtod(m, struct ip *); 341 th = (struct tcphdr *)(ip + 1); 342 tlen = sizeof(*ip) + sizeof(*th); 343 if (th0) { 344 bcopy(template, ip, sizeof(*ip)); 345 bcopy(th0, th, sizeof(*th)); 346 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, u_int32_t); 347 } else { 348 bcopy(template, ip, tlen); 349 } 350 break; 351 } 352 if (th0) 353 xchg(th->th_dport, th->th_sport, u_int16_t); 354 else 355 flags = TH_ACK; 356 #undef xchg 357 358 th->th_seq = htonl(seq); 359 th->th_ack = htonl(ack); 360 th->th_x2 = 0; 361 th->th_off = sizeof (struct tcphdr) >> 2; 362 th->th_flags = flags; 363 if (tp) 364 win >>= tp->rcv_scale; 365 if (win > TCP_MAXWIN) 366 win = TCP_MAXWIN; 367 th->th_win = htons((u_int16_t)win); 368 th->th_urp = 0; 369 370 if (tp && (tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 371 (flags & TH_RST) == 0 && (tp->t_flags & TF_RCVD_TSTMP)) { 372 u_int32_t *lp = (u_int32_t *)(th + 1); 373 /* Form timestamp option as shown in appendix A of RFC 1323. */ 374 *lp++ = htonl(TCPOPT_TSTAMP_HDR); 375 *lp++ = htonl(tcp_now + tp->ts_modulate); 376 *lp = htonl(tp->ts_recent); 377 tlen += TCPOLEN_TSTAMP_APPA; 378 th->th_off = (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_APPA) >> 2; 379 } 380 381 m->m_len = tlen; 382 m->m_pkthdr.len = tlen; 383 m->m_pkthdr.ph_ifidx = 0; 384 m->m_pkthdr.csum_flags |= M_TCP_CSUM_OUT; 385 386 /* force routing table */ 387 if (tp) 388 m->m_pkthdr.ph_rtableid = tp->t_inpcb->inp_rtableid; 389 else 390 m->m_pkthdr.ph_rtableid = rtableid; 391 392 switch (af) { 393 #ifdef INET6 394 case AF_INET6: 395 ip6->ip6_flow = htonl(0x60000000); 396 ip6->ip6_nxt = IPPROTO_TCP; 397 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL); /*XXX*/ 398 ip6->ip6_plen = tlen - sizeof(struct ip6_hdr); 399 ip6->ip6_plen = htons(ip6->ip6_plen); 400 ip6_output(m, tp ? tp->t_inpcb->inp_outputopts6 : NULL, 401 tp ? &tp->t_inpcb->inp_route6 : NULL, 402 0, NULL, 403 tp ? tp->t_inpcb : NULL); 404 break; 405 #endif /* INET6 */ 406 case AF_INET: 407 ip->ip_len = htons(tlen); 408 ip->ip_ttl = ip_defttl; 409 ip->ip_tos = 0; 410 ip_output(m, NULL, 411 tp ? &tp->t_inpcb->inp_route : NULL, 412 ip_mtudisc ? IP_MTUDISC : 0, NULL, 413 tp ? tp->t_inpcb : NULL, 0); 414 break; 415 } 416 } 417 418 /* 419 * Create a new TCP control block, making an 420 * empty reassembly queue and hooking it to the argument 421 * protocol control block. 422 */ 423 struct tcpcb * 424 tcp_newtcpcb(struct inpcb *inp) 425 { 426 struct tcpcb *tp; 427 int i; 428 429 tp = pool_get(&tcpcb_pool, PR_NOWAIT|PR_ZERO); 430 if (tp == NULL) 431 return (NULL); 432 TAILQ_INIT(&tp->t_segq); 433 tp->t_maxseg = tcp_mssdflt; 434 tp->t_maxopd = 0; 435 436 TCP_INIT_DELACK(tp); 437 for (i = 0; i < TCPT_NTIMERS; i++) 438 TCP_TIMER_INIT(tp, i); 439 timeout_set(&tp->t_reap_to, tcp_reaper, tp); 440 441 #ifdef TCP_SACK 442 tp->sack_enable = tcp_do_sack; 443 #endif 444 tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; 445 tp->t_inpcb = inp; 446 /* 447 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 448 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 449 * reasonable initial retransmit time. 450 */ 451 tp->t_srtt = TCPTV_SRTTBASE; 452 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << 453 (TCP_RTTVAR_SHIFT + TCP_RTT_BASE_SHIFT - 1); 454 tp->t_rttmin = TCPTV_MIN; 455 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 456 TCPTV_MIN, TCPTV_REXMTMAX); 457 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 458 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 459 460 tp->t_pmtud_mtu_sent = 0; 461 tp->t_pmtud_mss_acked = 0; 462 463 #ifdef INET6 464 /* we disallow IPv4 mapped address completely. */ 465 if ((inp->inp_flags & INP_IPV6) == 0) 466 tp->pf = PF_INET; 467 else 468 tp->pf = PF_INET6; 469 #else 470 tp->pf = PF_INET; 471 #endif 472 473 #ifdef INET6 474 if (inp->inp_flags & INP_IPV6) 475 inp->inp_ipv6.ip6_hlim = ip6_defhlim; 476 else 477 #endif /* INET6 */ 478 inp->inp_ip.ip_ttl = ip_defttl; 479 480 inp->inp_ppcb = (caddr_t)tp; 481 return (tp); 482 } 483 484 /* 485 * Drop a TCP connection, reporting 486 * the specified error. If connection is synchronized, 487 * then send a RST to peer. 488 */ 489 struct tcpcb * 490 tcp_drop(struct tcpcb *tp, int errno) 491 { 492 struct socket *so = tp->t_inpcb->inp_socket; 493 494 if (TCPS_HAVERCVDSYN(tp->t_state)) { 495 tp->t_state = TCPS_CLOSED; 496 (void) tcp_output(tp); 497 tcpstat.tcps_drops++; 498 } else 499 tcpstat.tcps_conndrops++; 500 if (errno == ETIMEDOUT && tp->t_softerror) 501 errno = tp->t_softerror; 502 so->so_error = errno; 503 return (tcp_close(tp)); 504 } 505 506 /* 507 * Close a TCP control block: 508 * discard all space held by the tcp 509 * discard internet protocol block 510 * wake up any sleepers 511 */ 512 struct tcpcb * 513 tcp_close(struct tcpcb *tp) 514 { 515 struct inpcb *inp = tp->t_inpcb; 516 struct socket *so = inp->inp_socket; 517 #ifdef TCP_SACK 518 struct sackhole *p, *q; 519 #endif 520 521 /* free the reassembly queue, if any */ 522 tcp_freeq(tp); 523 524 tcp_canceltimers(tp); 525 TCP_CLEAR_DELACK(tp); 526 syn_cache_cleanup(tp); 527 528 #ifdef TCP_SACK 529 /* Free SACK holes. */ 530 q = p = tp->snd_holes; 531 while (p != 0) { 532 q = p->next; 533 pool_put(&sackhl_pool, p); 534 p = q; 535 } 536 #endif 537 m_free(tp->t_template); 538 539 tp->t_flags |= TF_DEAD; 540 timeout_add(&tp->t_reap_to, 0); 541 542 inp->inp_ppcb = 0; 543 soisdisconnected(so); 544 in_pcbdetach(inp); 545 return (NULL); 546 } 547 548 void 549 tcp_reaper(void *arg) 550 { 551 struct tcpcb *tp = arg; 552 553 pool_put(&tcpcb_pool, tp); 554 tcpstat.tcps_closed++; 555 } 556 557 int 558 tcp_freeq(struct tcpcb *tp) 559 { 560 struct tcpqent *qe; 561 int rv = 0; 562 563 while ((qe = TAILQ_FIRST(&tp->t_segq)) != NULL) { 564 TAILQ_REMOVE(&tp->t_segq, qe, tcpqe_q); 565 m_freem(qe->tcpqe_m); 566 pool_put(&tcpqe_pool, qe); 567 rv = 1; 568 } 569 return (rv); 570 } 571 572 /* 573 * Compute proper scaling value for receiver window from buffer space 574 */ 575 576 void 577 tcp_rscale(struct tcpcb *tp, u_long hiwat) 578 { 579 tp->request_r_scale = 0; 580 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 581 TCP_MAXWIN << tp->request_r_scale < hiwat) 582 tp->request_r_scale++; 583 } 584 585 /* 586 * Notify a tcp user of an asynchronous error; 587 * store error as soft error, but wake up user 588 * (for now, won't do anything until can select for soft error). 589 */ 590 void 591 tcp_notify(struct inpcb *inp, int error) 592 { 593 struct tcpcb *tp = intotcpcb(inp); 594 struct socket *so = inp->inp_socket; 595 596 /* 597 * Ignore some errors if we are hooked up. 598 * If connection hasn't completed, has retransmitted several times, 599 * and receives a second error, give up now. This is better 600 * than waiting a long time to establish a connection that 601 * can never complete. 602 */ 603 if (tp->t_state == TCPS_ESTABLISHED && 604 (error == EHOSTUNREACH || error == ENETUNREACH || 605 error == EHOSTDOWN)) { 606 return; 607 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 608 tp->t_rxtshift > 3 && tp->t_softerror) 609 so->so_error = error; 610 else 611 tp->t_softerror = error; 612 wakeup((caddr_t) &so->so_timeo); 613 sorwakeup(so); 614 sowwakeup(so); 615 } 616 617 #ifdef INET6 618 void 619 tcp6_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *d) 620 { 621 struct tcphdr th; 622 struct tcpcb *tp; 623 void (*notify)(struct inpcb *, int) = tcp_notify; 624 struct ip6_hdr *ip6; 625 const struct sockaddr_in6 *sa6_src = NULL; 626 struct sockaddr_in6 *sa6 = satosin6(sa); 627 struct inpcb *inp; 628 struct mbuf *m; 629 tcp_seq seq; 630 int off; 631 struct { 632 u_int16_t th_sport; 633 u_int16_t th_dport; 634 u_int32_t th_seq; 635 } *thp; 636 637 if (sa->sa_family != AF_INET6 || 638 sa->sa_len != sizeof(struct sockaddr_in6) || 639 IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) || 640 IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) 641 return; 642 if ((unsigned)cmd >= PRC_NCMDS) 643 return; 644 else if (cmd == PRC_QUENCH) { 645 /* 646 * Don't honor ICMP Source Quench messages meant for 647 * TCP connections. 648 */ 649 /* XXX there's no PRC_QUENCH in IPv6 */ 650 return; 651 } else if (PRC_IS_REDIRECT(cmd)) 652 notify = in_rtchange, d = NULL; 653 else if (cmd == PRC_MSGSIZE) 654 ; /* special code is present, see below */ 655 else if (cmd == PRC_HOSTDEAD) 656 d = NULL; 657 else if (inet6ctlerrmap[cmd] == 0) 658 return; 659 660 /* if the parameter is from icmp6, decode it. */ 661 if (d != NULL) { 662 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 663 m = ip6cp->ip6c_m; 664 ip6 = ip6cp->ip6c_ip6; 665 off = ip6cp->ip6c_off; 666 sa6_src = ip6cp->ip6c_src; 667 } else { 668 m = NULL; 669 ip6 = NULL; 670 sa6_src = &sa6_any; 671 } 672 673 if (ip6) { 674 /* 675 * XXX: We assume that when ip6 is non NULL, 676 * M and OFF are valid. 677 */ 678 679 /* check if we can safely examine src and dst ports */ 680 if (m->m_pkthdr.len < off + sizeof(*thp)) 681 return; 682 683 bzero(&th, sizeof(th)); 684 #ifdef DIAGNOSTIC 685 if (sizeof(*thp) > sizeof(th)) 686 panic("assumption failed in tcp6_ctlinput"); 687 #endif 688 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 689 690 /* 691 * Check to see if we have a valid TCP connection 692 * corresponding to the address in the ICMPv6 message 693 * payload. 694 */ 695 inp = in6_pcbhashlookup(&tcbtable, &sa6->sin6_addr, 696 th.th_dport, (struct in6_addr *)&sa6_src->sin6_addr, 697 th.th_sport, rdomain); 698 if (cmd == PRC_MSGSIZE) { 699 /* 700 * Depending on the value of "valid" and routing table 701 * size (mtudisc_{hi,lo}wat), we will: 702 * - recalcurate the new MTU and create the 703 * corresponding routing entry, or 704 * - ignore the MTU change notification. 705 */ 706 icmp6_mtudisc_update((struct ip6ctlparam *)d, inp != NULL); 707 return; 708 } 709 if (inp) { 710 seq = ntohl(th.th_seq); 711 if (inp->inp_socket && 712 (tp = intotcpcb(inp)) && 713 SEQ_GEQ(seq, tp->snd_una) && 714 SEQ_LT(seq, tp->snd_max)) 715 notify(inp, inet6ctlerrmap[cmd]); 716 } else if (inet6ctlerrmap[cmd] == EHOSTUNREACH || 717 inet6ctlerrmap[cmd] == ENETUNREACH || 718 inet6ctlerrmap[cmd] == EHOSTDOWN) 719 syn_cache_unreach((struct sockaddr *)sa6_src, 720 sa, &th, rdomain); 721 } else { 722 (void) in6_pcbnotify(&tcbtable, sa6, 0, 723 sa6_src, 0, rdomain, cmd, NULL, notify); 724 } 725 } 726 #endif 727 728 void * 729 tcp_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *v) 730 { 731 struct ip *ip = v; 732 struct tcphdr *th; 733 struct tcpcb *tp; 734 struct inpcb *inp; 735 struct in_addr faddr; 736 tcp_seq seq; 737 u_int mtu; 738 void (*notify)(struct inpcb *, int) = tcp_notify; 739 int errno; 740 741 if (sa->sa_family != AF_INET) 742 return NULL; 743 faddr = satosin(sa)->sin_addr; 744 if (faddr.s_addr == INADDR_ANY) 745 return NULL; 746 747 if ((unsigned)cmd >= PRC_NCMDS) 748 return NULL; 749 errno = inetctlerrmap[cmd]; 750 if (cmd == PRC_QUENCH) 751 /* 752 * Don't honor ICMP Source Quench messages meant for 753 * TCP connections. 754 */ 755 return NULL; 756 else if (PRC_IS_REDIRECT(cmd)) 757 notify = in_rtchange, ip = 0; 758 else if (cmd == PRC_MSGSIZE && ip_mtudisc && ip) { 759 /* 760 * Verify that the packet in the icmp payload refers 761 * to an existing TCP connection. 762 */ 763 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 764 seq = ntohl(th->th_seq); 765 inp = in_pcbhashlookup(&tcbtable, 766 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 767 rdomain); 768 if (inp && (tp = intotcpcb(inp)) && 769 SEQ_GEQ(seq, tp->snd_una) && 770 SEQ_LT(seq, tp->snd_max)) { 771 struct icmp *icp; 772 icp = (struct icmp *)((caddr_t)ip - 773 offsetof(struct icmp, icmp_ip)); 774 775 /* 776 * If the ICMP message advertises a Next-Hop MTU 777 * equal or larger than the maximum packet size we have 778 * ever sent, drop the message. 779 */ 780 mtu = (u_int)ntohs(icp->icmp_nextmtu); 781 if (mtu >= tp->t_pmtud_mtu_sent) 782 return NULL; 783 if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) { 784 /* 785 * Calculate new MTU, and create corresponding 786 * route (traditional PMTUD). 787 */ 788 tp->t_flags &= ~TF_PMTUD_PEND; 789 icmp_mtudisc(icp, inp->inp_rtableid); 790 } else { 791 /* 792 * Record the information got in the ICMP 793 * message; act on it later. 794 * If we had already recorded an ICMP message, 795 * replace the old one only if the new message 796 * refers to an older TCP segment 797 */ 798 if (tp->t_flags & TF_PMTUD_PEND) { 799 if (SEQ_LT(tp->t_pmtud_th_seq, seq)) 800 return NULL; 801 } else 802 tp->t_flags |= TF_PMTUD_PEND; 803 tp->t_pmtud_th_seq = seq; 804 tp->t_pmtud_nextmtu = icp->icmp_nextmtu; 805 tp->t_pmtud_ip_len = icp->icmp_ip.ip_len; 806 tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl; 807 return NULL; 808 } 809 } else { 810 /* ignore if we don't have a matching connection */ 811 return NULL; 812 } 813 notify = tcp_mtudisc, ip = 0; 814 } else if (cmd == PRC_MTUINC) 815 notify = tcp_mtudisc_increase, ip = 0; 816 else if (cmd == PRC_HOSTDEAD) 817 ip = 0; 818 else if (errno == 0) 819 return NULL; 820 821 if (ip) { 822 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 823 inp = in_pcbhashlookup(&tcbtable, 824 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 825 rdomain); 826 if (inp) { 827 seq = ntohl(th->th_seq); 828 if (inp->inp_socket && 829 (tp = intotcpcb(inp)) && 830 SEQ_GEQ(seq, tp->snd_una) && 831 SEQ_LT(seq, tp->snd_max)) 832 notify(inp, errno); 833 } else if (inetctlerrmap[cmd] == EHOSTUNREACH || 834 inetctlerrmap[cmd] == ENETUNREACH || 835 inetctlerrmap[cmd] == EHOSTDOWN) { 836 struct sockaddr_in sin; 837 838 bzero(&sin, sizeof(sin)); 839 sin.sin_len = sizeof(sin); 840 sin.sin_family = AF_INET; 841 sin.sin_port = th->th_sport; 842 sin.sin_addr = ip->ip_src; 843 syn_cache_unreach(sintosa(&sin), sa, th, rdomain); 844 } 845 } else 846 in_pcbnotifyall(&tcbtable, sa, rdomain, errno, notify); 847 848 return NULL; 849 } 850 851 852 #ifdef INET6 853 /* 854 * Path MTU Discovery handlers. 855 */ 856 void 857 tcp6_mtudisc_callback(struct sockaddr_in6 *sin6, u_int rdomain) 858 { 859 (void) in6_pcbnotify(&tcbtable, sin6, 0, 860 &sa6_any, 0, rdomain, PRC_MSGSIZE, NULL, tcp_mtudisc); 861 } 862 #endif /* INET6 */ 863 864 /* 865 * On receipt of path MTU corrections, flush old route and replace it 866 * with the new one. Retransmit all unacknowledged packets, to ensure 867 * that all packets will be received. 868 */ 869 void 870 tcp_mtudisc(struct inpcb *inp, int errno) 871 { 872 struct tcpcb *tp = intotcpcb(inp); 873 struct rtentry *rt = in_pcbrtentry(inp); 874 int change = 0; 875 876 if (tp != 0) { 877 int orig_maxseg = tp->t_maxseg; 878 if (rt != 0) { 879 /* 880 * If this was not a host route, remove and realloc. 881 */ 882 if ((rt->rt_flags & RTF_HOST) == 0) { 883 in_rtchange(inp, errno); 884 if ((rt = in_pcbrtentry(inp)) == 0) 885 return; 886 } 887 if (orig_maxseg != tp->t_maxseg || 888 (rt->rt_rmx.rmx_locks & RTV_MTU)) 889 change = 1; 890 } 891 tcp_mss(tp, -1); 892 893 /* 894 * Resend unacknowledged packets 895 */ 896 tp->snd_nxt = tp->snd_una; 897 if (change || errno > 0) 898 tcp_output(tp); 899 } 900 } 901 902 void 903 tcp_mtudisc_increase(struct inpcb *inp, int errno) 904 { 905 struct tcpcb *tp = intotcpcb(inp); 906 struct rtentry *rt = in_pcbrtentry(inp); 907 908 if (tp != 0 && rt != 0) { 909 /* 910 * If this was a host route, remove and realloc. 911 */ 912 if (rt->rt_flags & RTF_HOST) 913 in_rtchange(inp, errno); 914 915 /* also takes care of congestion window */ 916 tcp_mss(tp, -1); 917 } 918 } 919 920 /* 921 * Generate new ISNs with a method based on RFC1948 922 */ 923 #define TCP_ISS_CONN_INC 4096 924 int tcp_secret_init; 925 u_char tcp_secret[16]; 926 SHA2_CTX tcp_secret_ctx; 927 928 void 929 tcp_set_iss_tsm(struct tcpcb *tp) 930 { 931 SHA2_CTX ctx; 932 union { 933 uint8_t bytes[SHA512_DIGEST_LENGTH]; 934 uint32_t words[2]; 935 } digest; 936 u_int rdomain = rtable_l2(tp->t_inpcb->inp_rtableid); 937 938 if (tcp_secret_init == 0) { 939 arc4random_buf(tcp_secret, sizeof(tcp_secret)); 940 SHA512Init(&tcp_secret_ctx); 941 SHA512Update(&tcp_secret_ctx, tcp_secret, sizeof(tcp_secret)); 942 tcp_secret_init = 1; 943 } 944 ctx = tcp_secret_ctx; 945 SHA512Update(&ctx, &rdomain, sizeof(rdomain)); 946 SHA512Update(&ctx, &tp->t_inpcb->inp_lport, sizeof(u_short)); 947 SHA512Update(&ctx, &tp->t_inpcb->inp_fport, sizeof(u_short)); 948 if (tp->pf == AF_INET6) { 949 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr6, 950 sizeof(struct in6_addr)); 951 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr6, 952 sizeof(struct in6_addr)); 953 } else { 954 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr, 955 sizeof(struct in_addr)); 956 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr, 957 sizeof(struct in_addr)); 958 } 959 SHA512Final(digest.bytes, &ctx); 960 tcp_iss += TCP_ISS_CONN_INC; 961 tp->iss = digest.words[0] + tcp_iss; 962 tp->ts_modulate = digest.words[1]; 963 } 964 965 #ifdef TCP_SIGNATURE 966 int 967 tcp_signature_tdb_attach(void) 968 { 969 return (0); 970 } 971 972 int 973 tcp_signature_tdb_init(struct tdb *tdbp, struct xformsw *xsp, 974 struct ipsecinit *ii) 975 { 976 if ((ii->ii_authkeylen < 1) || (ii->ii_authkeylen > 80)) 977 return (EINVAL); 978 979 tdbp->tdb_amxkey = malloc(ii->ii_authkeylen, M_XDATA, M_NOWAIT); 980 if (tdbp->tdb_amxkey == NULL) 981 return (ENOMEM); 982 bcopy(ii->ii_authkey, tdbp->tdb_amxkey, ii->ii_authkeylen); 983 tdbp->tdb_amxkeylen = ii->ii_authkeylen; 984 985 return (0); 986 } 987 988 int 989 tcp_signature_tdb_zeroize(struct tdb *tdbp) 990 { 991 if (tdbp->tdb_amxkey) { 992 explicit_bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); 993 free(tdbp->tdb_amxkey, M_XDATA, 0); 994 tdbp->tdb_amxkey = NULL; 995 } 996 997 return (0); 998 } 999 1000 int 1001 tcp_signature_tdb_input(struct mbuf *m, struct tdb *tdbp, int skip, int protoff) 1002 { 1003 return (0); 1004 } 1005 1006 int 1007 tcp_signature_tdb_output(struct mbuf *m, struct tdb *tdbp, struct mbuf **mp, 1008 int skip, int protoff) 1009 { 1010 return (EINVAL); 1011 } 1012 1013 int 1014 tcp_signature_apply(caddr_t fstate, caddr_t data, unsigned int len) 1015 { 1016 MD5Update((MD5_CTX *)fstate, (char *)data, len); 1017 return 0; 1018 } 1019 1020 int 1021 tcp_signature(struct tdb *tdb, int af, struct mbuf *m, struct tcphdr *th, 1022 int iphlen, int doswap, char *sig) 1023 { 1024 MD5_CTX ctx; 1025 int len; 1026 struct tcphdr th0; 1027 1028 MD5Init(&ctx); 1029 1030 switch(af) { 1031 case 0: 1032 case AF_INET: { 1033 struct ippseudo ippseudo; 1034 struct ip *ip; 1035 1036 ip = mtod(m, struct ip *); 1037 1038 ippseudo.ippseudo_src = ip->ip_src; 1039 ippseudo.ippseudo_dst = ip->ip_dst; 1040 ippseudo.ippseudo_pad = 0; 1041 ippseudo.ippseudo_p = IPPROTO_TCP; 1042 ippseudo.ippseudo_len = htons(m->m_pkthdr.len - iphlen); 1043 1044 MD5Update(&ctx, (char *)&ippseudo, 1045 sizeof(struct ippseudo)); 1046 break; 1047 } 1048 #ifdef INET6 1049 case AF_INET6: { 1050 struct ip6_hdr_pseudo ip6pseudo; 1051 struct ip6_hdr *ip6; 1052 1053 ip6 = mtod(m, struct ip6_hdr *); 1054 bzero(&ip6pseudo, sizeof(ip6pseudo)); 1055 ip6pseudo.ip6ph_src = ip6->ip6_src; 1056 ip6pseudo.ip6ph_dst = ip6->ip6_dst; 1057 in6_clearscope(&ip6pseudo.ip6ph_src); 1058 in6_clearscope(&ip6pseudo.ip6ph_dst); 1059 ip6pseudo.ip6ph_nxt = IPPROTO_TCP; 1060 ip6pseudo.ip6ph_len = htonl(m->m_pkthdr.len - iphlen); 1061 1062 MD5Update(&ctx, (char *)&ip6pseudo, 1063 sizeof(ip6pseudo)); 1064 break; 1065 } 1066 #endif 1067 } 1068 1069 th0 = *th; 1070 th0.th_sum = 0; 1071 1072 if (doswap) { 1073 th0.th_seq = htonl(th0.th_seq); 1074 th0.th_ack = htonl(th0.th_ack); 1075 th0.th_win = htons(th0.th_win); 1076 th0.th_urp = htons(th0.th_urp); 1077 } 1078 MD5Update(&ctx, (char *)&th0, sizeof(th0)); 1079 1080 len = m->m_pkthdr.len - iphlen - th->th_off * sizeof(uint32_t); 1081 1082 if (len > 0 && 1083 m_apply(m, iphlen + th->th_off * sizeof(uint32_t), len, 1084 tcp_signature_apply, (caddr_t)&ctx)) 1085 return (-1); 1086 1087 MD5Update(&ctx, tdb->tdb_amxkey, tdb->tdb_amxkeylen); 1088 MD5Final(sig, &ctx); 1089 1090 return (0); 1091 } 1092 #endif /* TCP_SIGNATURE */ 1093