1 /* $OpenBSD: tcp_subr.c,v 1.138 2014/11/18 02:37:31 tedu 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 #include <net/if.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 <netinet/ip_icmp.h> 89 #include <netinet/tcp.h> 90 #include <netinet/tcp_fsm.h> 91 #include <netinet/tcp_seq.h> 92 #include <netinet/tcp_timer.h> 93 #include <netinet/tcp_var.h> 94 #include <netinet/tcpip.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 /* patchable/settable parameters for tcp */ 104 int tcp_mssdflt = TCP_MSS; 105 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 106 107 /* values controllable via sysctl */ 108 int tcp_do_rfc1323 = 1; 109 #ifdef TCP_SACK 110 int tcp_do_sack = 1; /* RFC 2018 selective ACKs */ 111 #endif 112 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ 113 #ifdef TCP_ECN 114 int tcp_do_ecn = 0; /* RFC3168 ECN enabled/disabled? */ 115 #endif 116 int tcp_do_rfc3390 = 2; /* Increase TCP's Initial Window to 10*mss */ 117 118 u_int32_t tcp_now = 1; 119 120 #ifndef TCB_INITIAL_HASH_SIZE 121 #define TCB_INITIAL_HASH_SIZE 128 122 #endif 123 124 /* syn hash parameters */ 125 #define TCP_SYN_HASH_SIZE 293 126 #define TCP_SYN_BUCKET_SIZE 35 127 int tcp_syn_cache_size = TCP_SYN_HASH_SIZE; 128 int tcp_syn_cache_limit = TCP_SYN_HASH_SIZE*TCP_SYN_BUCKET_SIZE; 129 int tcp_syn_bucket_limit = 3*TCP_SYN_BUCKET_SIZE; 130 struct syn_cache_head tcp_syn_cache[TCP_SYN_HASH_SIZE]; 131 132 int tcp_reass_limit = NMBCLUSTERS / 2; /* hardlimit for tcpqe_pool */ 133 #ifdef TCP_SACK 134 int tcp_sackhole_limit = 32*1024; /* hardlimit for sackhl_pool */ 135 #endif 136 137 struct pool tcpcb_pool; 138 struct pool tcpqe_pool; 139 #ifdef TCP_SACK 140 struct pool sackhl_pool; 141 #endif 142 143 struct tcpstat tcpstat; /* tcp statistics */ 144 tcp_seq tcp_iss; 145 146 /* 147 * Tcp initialization 148 */ 149 void 150 tcp_init() 151 { 152 tcp_iss = 1; /* wrong */ 153 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcb", NULL); 154 pool_init(&tcpqe_pool, sizeof(struct tcpqent), 0, 0, 0, "tcpqe", NULL); 155 pool_sethardlimit(&tcpqe_pool, tcp_reass_limit, NULL, 0); 156 #ifdef TCP_SACK 157 pool_init(&sackhl_pool, sizeof(struct sackhole), 0, 0, 0, "sackhl", 158 NULL); 159 pool_sethardlimit(&sackhl_pool, tcp_sackhole_limit, NULL, 0); 160 #endif /* TCP_SACK */ 161 in_pcbinit(&tcbtable, TCB_INITIAL_HASH_SIZE); 162 163 #ifdef INET6 164 /* 165 * Since sizeof(struct ip6_hdr) > sizeof(struct ip), we 166 * do max length checks/computations only on the former. 167 */ 168 if (max_protohdr < (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))) 169 max_protohdr = (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)); 170 if ((max_linkhdr + sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) > 171 MHLEN) 172 panic("tcp_init"); 173 174 icmp6_mtudisc_callback_register(tcp6_mtudisc_callback); 175 #endif /* INET6 */ 176 177 /* Initialize the compressed state engine. */ 178 syn_cache_init(); 179 180 /* Initialize timer state. */ 181 tcp_timer_init(); 182 } 183 184 /* 185 * Create template to be used to send tcp packets on a connection. 186 * Call after host entry created, allocates an mbuf and fills 187 * in a skeletal tcp/ip header, minimizing the amount of work 188 * necessary when the connection is used. 189 * 190 * To support IPv6 in addition to IPv4 and considering that the sizes of 191 * the IPv4 and IPv6 headers are not the same, we now use a separate pointer 192 * for the TCP header. Also, we made the former tcpiphdr header pointer 193 * into just an IP overlay pointer, with casting as appropriate for v6. rja 194 */ 195 struct mbuf * 196 tcp_template(tp) 197 struct tcpcb *tp; 198 { 199 struct inpcb *inp = tp->t_inpcb; 200 struct mbuf *m; 201 struct tcphdr *th; 202 203 if ((m = tp->t_template) == 0) { 204 m = m_get(M_DONTWAIT, MT_HEADER); 205 if (m == NULL) 206 return (0); 207 208 switch (tp->pf) { 209 case 0: /*default to PF_INET*/ 210 #ifdef INET 211 case AF_INET: 212 m->m_len = sizeof(struct ip); 213 break; 214 #endif /* INET */ 215 #ifdef INET6 216 case AF_INET6: 217 m->m_len = sizeof(struct ip6_hdr); 218 break; 219 #endif /* INET6 */ 220 } 221 m->m_len += sizeof (struct tcphdr); 222 223 /* 224 * The link header, network header, TCP header, and TCP options 225 * all must fit in this mbuf. For now, assume the worst case of 226 * TCP options size. Eventually, compute this from tp flags. 227 */ 228 if (m->m_len + MAX_TCPOPTLEN + max_linkhdr >= MHLEN) { 229 MCLGET(m, M_DONTWAIT); 230 if ((m->m_flags & M_EXT) == 0) { 231 m_free(m); 232 return (0); 233 } 234 } 235 } 236 237 switch(tp->pf) { 238 #ifdef INET 239 case AF_INET: 240 { 241 struct ipovly *ipovly; 242 243 ipovly = mtod(m, struct ipovly *); 244 245 bzero(ipovly->ih_x1, sizeof ipovly->ih_x1); 246 ipovly->ih_pr = IPPROTO_TCP; 247 ipovly->ih_len = htons(sizeof (struct tcphdr)); 248 ipovly->ih_src = inp->inp_laddr; 249 ipovly->ih_dst = inp->inp_faddr; 250 251 th = (struct tcphdr *)(mtod(m, caddr_t) + 252 sizeof(struct ip)); 253 } 254 break; 255 #endif /* INET */ 256 #ifdef INET6 257 case AF_INET6: 258 { 259 struct ip6_hdr *ip6; 260 261 ip6 = mtod(m, struct ip6_hdr *); 262 263 ip6->ip6_src = inp->inp_laddr6; 264 ip6->ip6_dst = inp->inp_faddr6; 265 ip6->ip6_flow = htonl(0x60000000) | 266 (inp->inp_flowinfo & IPV6_FLOWLABEL_MASK); 267 268 ip6->ip6_nxt = IPPROTO_TCP; 269 ip6->ip6_plen = htons(sizeof(struct tcphdr)); /*XXX*/ 270 ip6->ip6_hlim = in6_selecthlim(inp, NULL); /*XXX*/ 271 272 th = (struct tcphdr *)(mtod(m, caddr_t) + 273 sizeof(struct ip6_hdr)); 274 } 275 break; 276 #endif /* INET6 */ 277 } 278 279 th->th_sport = inp->inp_lport; 280 th->th_dport = inp->inp_fport; 281 th->th_seq = 0; 282 th->th_ack = 0; 283 th->th_x2 = 0; 284 th->th_off = 5; 285 th->th_flags = 0; 286 th->th_win = 0; 287 th->th_urp = 0; 288 th->th_sum = 0; 289 return (m); 290 } 291 292 /* 293 * Send a single message to the TCP at address specified by 294 * the given TCP/IP header. If m == 0, then we make a copy 295 * of the tcpiphdr at ti and send directly to the addressed host. 296 * This is used to force keep alive messages out using the TCP 297 * template for a connection tp->t_template. If flags are given 298 * then we send a message back to the TCP which originated the 299 * segment ti, and discard the mbuf containing it and any other 300 * attached mbufs. 301 * 302 * In any case the ack and sequence number of the transmitted 303 * segment are as specified by the parameters. 304 */ 305 #ifdef INET6 306 /* This function looks hairy, because it was so IPv4-dependent. */ 307 #endif /* INET6 */ 308 void 309 tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0, 310 tcp_seq ack, tcp_seq seq, int flags, u_int rtableid) 311 { 312 int tlen; 313 int win = 0; 314 struct mbuf *m = 0; 315 struct route *ro = 0; 316 struct tcphdr *th; 317 struct ip *ip; 318 #ifdef INET6 319 struct ip6_hdr *ip6; 320 #endif 321 int af; /* af on wire */ 322 323 if (tp) { 324 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 325 /* 326 * If this is called with an unconnected 327 * socket/tp/pcb (tp->pf is 0), we lose. 328 */ 329 af = tp->pf; 330 331 /* 332 * The route/route6 distinction is meaningless 333 * unless you're allocating space or passing parameters. 334 */ 335 ro = &tp->t_inpcb->inp_route; 336 } else 337 af = (((struct ip *)template)->ip_v == 6) ? AF_INET6 : AF_INET; 338 339 m = m_gethdr(M_DONTWAIT, MT_HEADER); 340 if (m == NULL) 341 return; 342 m->m_data += max_linkhdr; 343 tlen = 0; 344 345 #define xchg(a,b,type) do { type t; t=a; a=b; b=t; } while (0) 346 switch (af) { 347 #ifdef INET6 348 case AF_INET6: 349 ip6 = mtod(m, struct ip6_hdr *); 350 th = (struct tcphdr *)(ip6 + 1); 351 tlen = sizeof(*ip6) + sizeof(*th); 352 if (th0) { 353 bcopy(template, ip6, sizeof(*ip6)); 354 bcopy(th0, th, sizeof(*th)); 355 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 356 } else { 357 bcopy(template, ip6, tlen); 358 } 359 break; 360 #endif /* INET6 */ 361 case AF_INET: 362 ip = mtod(m, struct ip *); 363 th = (struct tcphdr *)(ip + 1); 364 tlen = sizeof(*ip) + sizeof(*th); 365 if (th0) { 366 bcopy(template, ip, sizeof(*ip)); 367 bcopy(th0, th, sizeof(*th)); 368 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, u_int32_t); 369 } else { 370 bcopy(template, ip, tlen); 371 } 372 break; 373 } 374 if (th0) 375 xchg(th->th_dport, th->th_sport, u_int16_t); 376 else 377 flags = TH_ACK; 378 #undef xchg 379 380 m->m_len = tlen; 381 m->m_pkthdr.len = tlen; 382 m->m_pkthdr.rcvif = (struct ifnet *) 0; 383 m->m_pkthdr.csum_flags |= M_TCP_CSUM_OUT; 384 th->th_seq = htonl(seq); 385 th->th_ack = htonl(ack); 386 th->th_x2 = 0; 387 th->th_off = sizeof (struct tcphdr) >> 2; 388 th->th_flags = flags; 389 if (tp) 390 win >>= tp->rcv_scale; 391 if (win > TCP_MAXWIN) 392 win = TCP_MAXWIN; 393 th->th_win = htons((u_int16_t)win); 394 th->th_urp = 0; 395 396 /* force routing table */ 397 if (tp) 398 m->m_pkthdr.ph_rtableid = tp->t_inpcb->inp_rtableid; 399 else 400 m->m_pkthdr.ph_rtableid = rtableid; 401 402 switch (af) { 403 #ifdef INET6 404 case AF_INET6: 405 ip6->ip6_flow = htonl(0x60000000); 406 ip6->ip6_nxt = IPPROTO_TCP; 407 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, NULL); /*XXX*/ 408 ip6->ip6_plen = tlen - sizeof(struct ip6_hdr); 409 HTONS(ip6->ip6_plen); 410 ip6_output(m, tp ? tp->t_inpcb->inp_outputopts6 : NULL, 411 (struct route_in6 *)ro, 0, NULL, NULL, 412 tp ? tp->t_inpcb : NULL); 413 break; 414 #endif /* INET6 */ 415 case AF_INET: 416 ip->ip_len = htons(tlen); 417 ip->ip_ttl = ip_defttl; 418 ip->ip_tos = 0; 419 ip_output(m, NULL, ro, ip_mtudisc ? IP_MTUDISC : 0, 420 NULL, tp ? tp->t_inpcb : NULL, 0); 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 */ 429 struct tcpcb * 430 tcp_newtcpcb(struct inpcb *inp) 431 { 432 struct tcpcb *tp; 433 int i; 434 435 tp = pool_get(&tcpcb_pool, PR_NOWAIT|PR_ZERO); 436 if (tp == NULL) 437 return (NULL); 438 TAILQ_INIT(&tp->t_segq); 439 tp->t_maxseg = tcp_mssdflt; 440 tp->t_maxopd = 0; 441 442 TCP_INIT_DELACK(tp); 443 for (i = 0; i < TCPT_NTIMERS; i++) 444 TCP_TIMER_INIT(tp, i); 445 timeout_set(&tp->t_reap_to, tcp_reaper, tp); 446 447 #ifdef TCP_SACK 448 tp->sack_enable = tcp_do_sack; 449 #endif 450 tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; 451 tp->t_inpcb = inp; 452 /* 453 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 454 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 455 * reasonable initial retransmit time. 456 */ 457 tp->t_srtt = TCPTV_SRTTBASE; 458 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << 459 (TCP_RTTVAR_SHIFT + TCP_RTT_BASE_SHIFT - 1); 460 tp->t_rttmin = TCPTV_MIN; 461 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 462 TCPTV_MIN, TCPTV_REXMTMAX); 463 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 464 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 465 466 tp->t_pmtud_mtu_sent = 0; 467 tp->t_pmtud_mss_acked = 0; 468 469 #ifdef INET6 470 /* we disallow IPv4 mapped address completely. */ 471 if ((inp->inp_flags & INP_IPV6) == 0) 472 tp->pf = PF_INET; 473 else 474 tp->pf = PF_INET6; 475 #else 476 tp->pf = PF_INET; 477 #endif 478 479 #ifdef INET6 480 if (inp->inp_flags & INP_IPV6) 481 inp->inp_ipv6.ip6_hlim = ip6_defhlim; 482 else 483 #endif /* INET6 */ 484 inp->inp_ip.ip_ttl = ip_defttl; 485 486 inp->inp_ppcb = (caddr_t)tp; 487 return (tp); 488 } 489 490 /* 491 * Drop a TCP connection, reporting 492 * the specified error. If connection is synchronized, 493 * then send a RST to peer. 494 */ 495 struct tcpcb * 496 tcp_drop(tp, errno) 497 struct tcpcb *tp; 498 int errno; 499 { 500 struct socket *so = tp->t_inpcb->inp_socket; 501 502 if (TCPS_HAVERCVDSYN(tp->t_state)) { 503 tp->t_state = TCPS_CLOSED; 504 (void) tcp_output(tp); 505 tcpstat.tcps_drops++; 506 } else 507 tcpstat.tcps_conndrops++; 508 if (errno == ETIMEDOUT && tp->t_softerror) 509 errno = tp->t_softerror; 510 so->so_error = errno; 511 return (tcp_close(tp)); 512 } 513 514 /* 515 * Close a TCP control block: 516 * discard all space held by the tcp 517 * discard internet protocol block 518 * wake up any sleepers 519 */ 520 struct tcpcb * 521 tcp_close(struct tcpcb *tp) 522 { 523 struct inpcb *inp = tp->t_inpcb; 524 struct socket *so = inp->inp_socket; 525 #ifdef TCP_SACK 526 struct sackhole *p, *q; 527 #endif 528 529 /* free the reassembly queue, if any */ 530 tcp_freeq(tp); 531 532 tcp_canceltimers(tp); 533 TCP_CLEAR_DELACK(tp); 534 syn_cache_cleanup(tp); 535 536 #ifdef TCP_SACK 537 /* Free SACK holes. */ 538 q = p = tp->snd_holes; 539 while (p != 0) { 540 q = p->next; 541 pool_put(&sackhl_pool, p); 542 p = q; 543 } 544 #endif 545 if (tp->t_template) 546 (void) m_free(tp->t_template); 547 548 tp->t_flags |= TF_DEAD; 549 timeout_add(&tp->t_reap_to, 0); 550 551 inp->inp_ppcb = 0; 552 soisdisconnected(so); 553 in_pcbdetach(inp); 554 return (NULL); 555 } 556 557 void 558 tcp_reaper(void *arg) 559 { 560 struct tcpcb *tp = arg; 561 int s; 562 563 s = splsoftnet(); 564 pool_put(&tcpcb_pool, tp); 565 splx(s); 566 tcpstat.tcps_closed++; 567 } 568 569 int 570 tcp_freeq(struct tcpcb *tp) 571 { 572 struct tcpqent *qe; 573 int rv = 0; 574 575 while ((qe = TAILQ_FIRST(&tp->t_segq)) != NULL) { 576 TAILQ_REMOVE(&tp->t_segq, qe, tcpqe_q); 577 m_freem(qe->tcpqe_m); 578 pool_put(&tcpqe_pool, qe); 579 rv = 1; 580 } 581 return (rv); 582 } 583 584 /* 585 * Compute proper scaling value for receiver window from buffer space 586 */ 587 588 void 589 tcp_rscale(struct tcpcb *tp, u_long hiwat) 590 { 591 tp->request_r_scale = 0; 592 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 593 TCP_MAXWIN << tp->request_r_scale < hiwat) 594 tp->request_r_scale++; 595 } 596 597 /* 598 * Notify a tcp user of an asynchronous error; 599 * store error as soft error, but wake up user 600 * (for now, won't do anything until can select for soft error). 601 */ 602 void 603 tcp_notify(inp, error) 604 struct inpcb *inp; 605 int error; 606 { 607 struct tcpcb *tp = intotcpcb(inp); 608 struct socket *so = inp->inp_socket; 609 610 /* 611 * Ignore some errors if we are hooked up. 612 * If connection hasn't completed, has retransmitted several times, 613 * and receives a second error, give up now. This is better 614 * than waiting a long time to establish a connection that 615 * can never complete. 616 */ 617 if (tp->t_state == TCPS_ESTABLISHED && 618 (error == EHOSTUNREACH || error == ENETUNREACH || 619 error == EHOSTDOWN)) { 620 return; 621 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 622 tp->t_rxtshift > 3 && tp->t_softerror) 623 so->so_error = error; 624 else 625 tp->t_softerror = error; 626 wakeup((caddr_t) &so->so_timeo); 627 sorwakeup(so); 628 sowwakeup(so); 629 } 630 631 #ifdef INET6 632 void 633 tcp6_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *d) 634 { 635 struct tcphdr th; 636 struct tcpcb *tp; 637 void (*notify)(struct inpcb *, int) = tcp_notify; 638 struct ip6_hdr *ip6; 639 const struct sockaddr_in6 *sa6_src = NULL; 640 struct sockaddr_in6 *sa6 = satosin6(sa); 641 struct inpcb *inp; 642 struct mbuf *m; 643 tcp_seq seq; 644 int off; 645 struct { 646 u_int16_t th_sport; 647 u_int16_t th_dport; 648 u_int32_t th_seq; 649 } *thp; 650 651 if (sa->sa_family != AF_INET6 || 652 sa->sa_len != sizeof(struct sockaddr_in6) || 653 IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) || 654 IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) 655 return; 656 if ((unsigned)cmd >= PRC_NCMDS) 657 return; 658 else if (cmd == PRC_QUENCH) { 659 /* 660 * Don't honor ICMP Source Quench messages meant for 661 * TCP connections. 662 */ 663 /* XXX there's no PRC_QUENCH in IPv6 */ 664 return; 665 } else if (PRC_IS_REDIRECT(cmd)) 666 notify = in_rtchange, d = NULL; 667 else if (cmd == PRC_MSGSIZE) 668 ; /* special code is present, see below */ 669 else if (cmd == PRC_HOSTDEAD) 670 d = NULL; 671 else if (inet6ctlerrmap[cmd] == 0) 672 return; 673 674 /* if the parameter is from icmp6, decode it. */ 675 if (d != NULL) { 676 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 677 m = ip6cp->ip6c_m; 678 ip6 = ip6cp->ip6c_ip6; 679 off = ip6cp->ip6c_off; 680 sa6_src = ip6cp->ip6c_src; 681 } else { 682 m = NULL; 683 ip6 = NULL; 684 sa6_src = &sa6_any; 685 } 686 687 if (ip6) { 688 /* 689 * XXX: We assume that when ip6 is non NULL, 690 * M and OFF are valid. 691 */ 692 693 /* check if we can safely examine src and dst ports */ 694 if (m->m_pkthdr.len < off + sizeof(*thp)) 695 return; 696 697 bzero(&th, sizeof(th)); 698 #ifdef DIAGNOSTIC 699 if (sizeof(*thp) > sizeof(th)) 700 panic("assumption failed in tcp6_ctlinput"); 701 #endif 702 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 703 704 /* 705 * Check to see if we have a valid TCP connection 706 * corresponding to the address in the ICMPv6 message 707 * payload. 708 */ 709 inp = in6_pcbhashlookup(&tcbtable, &sa6->sin6_addr, 710 th.th_dport, (struct in6_addr *)&sa6_src->sin6_addr, 711 th.th_sport, rdomain); 712 if (cmd == PRC_MSGSIZE) { 713 /* 714 * Depending on the value of "valid" and routing table 715 * size (mtudisc_{hi,lo}wat), we will: 716 * - recalcurate the new MTU and create the 717 * corresponding routing entry, or 718 * - ignore the MTU change notification. 719 */ 720 icmp6_mtudisc_update((struct ip6ctlparam *)d, inp != NULL); 721 return; 722 } 723 if (inp) { 724 seq = ntohl(th.th_seq); 725 if (inp->inp_socket && 726 (tp = intotcpcb(inp)) && 727 SEQ_GEQ(seq, tp->snd_una) && 728 SEQ_LT(seq, tp->snd_max)) 729 notify(inp, inet6ctlerrmap[cmd]); 730 } else if (syn_cache_count && 731 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 732 inet6ctlerrmap[cmd] == ENETUNREACH || 733 inet6ctlerrmap[cmd] == EHOSTDOWN)) 734 syn_cache_unreach((struct sockaddr *)sa6_src, 735 sa, &th, rdomain); 736 } else { 737 (void) in6_pcbnotify(&tcbtable, sa6, 0, 738 sa6_src, 0, rdomain, cmd, NULL, notify); 739 } 740 } 741 #endif 742 743 void * 744 tcp_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *v) 745 { 746 struct ip *ip = v; 747 struct tcphdr *th; 748 struct tcpcb *tp; 749 struct inpcb *inp; 750 struct in_addr faddr; 751 tcp_seq seq; 752 u_int mtu; 753 void (*notify)(struct inpcb *, int) = tcp_notify; 754 int errno; 755 756 if (sa->sa_family != AF_INET) 757 return NULL; 758 faddr = satosin(sa)->sin_addr; 759 if (faddr.s_addr == INADDR_ANY) 760 return NULL; 761 762 if ((unsigned)cmd >= PRC_NCMDS) 763 return NULL; 764 errno = inetctlerrmap[cmd]; 765 if (cmd == PRC_QUENCH) 766 /* 767 * Don't honor ICMP Source Quench messages meant for 768 * TCP connections. 769 */ 770 return NULL; 771 else if (PRC_IS_REDIRECT(cmd)) 772 notify = in_rtchange, ip = 0; 773 else if (cmd == PRC_MSGSIZE && ip_mtudisc && ip) { 774 /* 775 * Verify that the packet in the icmp payload refers 776 * to an existing TCP connection. 777 */ 778 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 779 seq = ntohl(th->th_seq); 780 inp = in_pcbhashlookup(&tcbtable, 781 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 782 rdomain); 783 if (inp && (tp = intotcpcb(inp)) && 784 SEQ_GEQ(seq, tp->snd_una) && 785 SEQ_LT(seq, tp->snd_max)) { 786 struct icmp *icp; 787 icp = (struct icmp *)((caddr_t)ip - 788 offsetof(struct icmp, icmp_ip)); 789 790 /* 791 * If the ICMP message advertises a Next-Hop MTU 792 * equal or larger than the maximum packet size we have 793 * ever sent, drop the message. 794 */ 795 mtu = (u_int)ntohs(icp->icmp_nextmtu); 796 if (mtu >= tp->t_pmtud_mtu_sent) 797 return NULL; 798 if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) { 799 /* 800 * Calculate new MTU, and create corresponding 801 * route (traditional PMTUD). 802 */ 803 tp->t_flags &= ~TF_PMTUD_PEND; 804 icmp_mtudisc(icp, inp->inp_rtableid); 805 } else { 806 /* 807 * Record the information got in the ICMP 808 * message; act on it later. 809 * If we had already recorded an ICMP message, 810 * replace the old one only if the new message 811 * refers to an older TCP segment 812 */ 813 if (tp->t_flags & TF_PMTUD_PEND) { 814 if (SEQ_LT(tp->t_pmtud_th_seq, seq)) 815 return NULL; 816 } else 817 tp->t_flags |= TF_PMTUD_PEND; 818 tp->t_pmtud_th_seq = seq; 819 tp->t_pmtud_nextmtu = icp->icmp_nextmtu; 820 tp->t_pmtud_ip_len = icp->icmp_ip.ip_len; 821 tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl; 822 return NULL; 823 } 824 } else { 825 /* ignore if we don't have a matching connection */ 826 return NULL; 827 } 828 notify = tcp_mtudisc, ip = 0; 829 } else if (cmd == PRC_MTUINC) 830 notify = tcp_mtudisc_increase, ip = 0; 831 else if (cmd == PRC_HOSTDEAD) 832 ip = 0; 833 else if (errno == 0) 834 return NULL; 835 836 if (ip) { 837 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 838 inp = in_pcbhashlookup(&tcbtable, 839 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 840 rdomain); 841 if (inp) { 842 seq = ntohl(th->th_seq); 843 if (inp->inp_socket && 844 (tp = intotcpcb(inp)) && 845 SEQ_GEQ(seq, tp->snd_una) && 846 SEQ_LT(seq, tp->snd_max)) 847 notify(inp, errno); 848 } else if (syn_cache_count && 849 (inetctlerrmap[cmd] == EHOSTUNREACH || 850 inetctlerrmap[cmd] == ENETUNREACH || 851 inetctlerrmap[cmd] == EHOSTDOWN)) { 852 struct sockaddr_in sin; 853 854 bzero(&sin, sizeof(sin)); 855 sin.sin_len = sizeof(sin); 856 sin.sin_family = AF_INET; 857 sin.sin_port = th->th_sport; 858 sin.sin_addr = ip->ip_src; 859 syn_cache_unreach((struct sockaddr *)&sin, 860 sa, th, rdomain); 861 } 862 } else 863 in_pcbnotifyall(&tcbtable, sa, rdomain, errno, notify); 864 865 return NULL; 866 } 867 868 869 #ifdef INET6 870 /* 871 * Path MTU Discovery handlers. 872 */ 873 void 874 tcp6_mtudisc_callback(sin6, rdomain) 875 struct sockaddr_in6 *sin6; 876 u_int rdomain; 877 { 878 (void) in6_pcbnotify(&tcbtable, sin6, 0, 879 &sa6_any, 0, rdomain, PRC_MSGSIZE, NULL, tcp_mtudisc); 880 } 881 #endif /* INET6 */ 882 883 /* 884 * On receipt of path MTU corrections, flush old route and replace it 885 * with the new one. Retransmit all unacknowledged packets, to ensure 886 * that all packets will be received. 887 */ 888 void 889 tcp_mtudisc(inp, errno) 890 struct inpcb *inp; 891 int errno; 892 { 893 struct tcpcb *tp = intotcpcb(inp); 894 struct rtentry *rt = in_pcbrtentry(inp); 895 int change = 0; 896 897 if (tp != 0) { 898 int orig_maxseg = tp->t_maxseg; 899 if (rt != 0) { 900 /* 901 * If this was not a host route, remove and realloc. 902 */ 903 if ((rt->rt_flags & RTF_HOST) == 0) { 904 in_rtchange(inp, errno); 905 if ((rt = in_pcbrtentry(inp)) == 0) 906 return; 907 } 908 if (orig_maxseg != tp->t_maxseg || 909 (rt->rt_rmx.rmx_locks & RTV_MTU)) 910 change = 1; 911 } 912 tcp_mss(tp, -1); 913 914 /* 915 * Resend unacknowledged packets 916 */ 917 tp->snd_nxt = tp->snd_una; 918 if (change || errno > 0) 919 tcp_output(tp); 920 } 921 } 922 923 void 924 tcp_mtudisc_increase(inp, errno) 925 struct inpcb *inp; 926 int errno; 927 { 928 struct tcpcb *tp = intotcpcb(inp); 929 struct rtentry *rt = in_pcbrtentry(inp); 930 931 if (tp != 0 && rt != 0) { 932 /* 933 * If this was a host route, remove and realloc. 934 */ 935 if (rt->rt_flags & RTF_HOST) 936 in_rtchange(inp, errno); 937 938 /* also takes care of congestion window */ 939 tcp_mss(tp, -1); 940 } 941 } 942 943 #define TCP_ISS_CONN_INC 4096 944 int tcp_secret_init; 945 u_char tcp_secret[16]; 946 SHA2_CTX tcp_secret_ctx; 947 948 void 949 tcp_set_iss_tsm(struct tcpcb *tp) 950 { 951 SHA2_CTX ctx; 952 union { 953 uint8_t bytes[SHA512_DIGEST_LENGTH]; 954 uint32_t words[2]; 955 } digest; 956 u_int rdomain = rtable_l2(tp->t_inpcb->inp_rtableid); 957 958 if (tcp_secret_init == 0) { 959 arc4random_buf(tcp_secret, sizeof(tcp_secret)); 960 SHA512Init(&tcp_secret_ctx); 961 SHA512Update(&tcp_secret_ctx, tcp_secret, sizeof(tcp_secret)); 962 tcp_secret_init = 1; 963 } 964 ctx = tcp_secret_ctx; 965 SHA512Update(&ctx, &rdomain, sizeof(rdomain)); 966 SHA512Update(&ctx, &tp->t_inpcb->inp_lport, sizeof(u_short)); 967 SHA512Update(&ctx, &tp->t_inpcb->inp_fport, sizeof(u_short)); 968 if (tp->pf == AF_INET6) { 969 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr6, 970 sizeof(struct in6_addr)); 971 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr6, 972 sizeof(struct in6_addr)); 973 } else { 974 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr, 975 sizeof(struct in_addr)); 976 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr, 977 sizeof(struct in_addr)); 978 } 979 SHA512Final(digest.bytes, &ctx); 980 tcp_iss += TCP_ISS_CONN_INC; 981 tp->iss = digest.words[0] + tcp_iss; 982 tp->ts_modulate = digest.words[1]; 983 } 984 985 #ifdef TCP_SIGNATURE 986 int 987 tcp_signature_tdb_attach() 988 { 989 return (0); 990 } 991 992 int 993 tcp_signature_tdb_init(tdbp, xsp, ii) 994 struct tdb *tdbp; 995 struct xformsw *xsp; 996 struct ipsecinit *ii; 997 { 998 if ((ii->ii_authkeylen < 1) || (ii->ii_authkeylen > 80)) 999 return (EINVAL); 1000 1001 tdbp->tdb_amxkey = malloc(ii->ii_authkeylen, M_XDATA, M_NOWAIT); 1002 if (tdbp->tdb_amxkey == NULL) 1003 return (ENOMEM); 1004 bcopy(ii->ii_authkey, tdbp->tdb_amxkey, ii->ii_authkeylen); 1005 tdbp->tdb_amxkeylen = ii->ii_authkeylen; 1006 1007 return (0); 1008 } 1009 1010 int 1011 tcp_signature_tdb_zeroize(tdbp) 1012 struct tdb *tdbp; 1013 { 1014 if (tdbp->tdb_amxkey) { 1015 explicit_bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); 1016 free(tdbp->tdb_amxkey, M_XDATA, 0); 1017 tdbp->tdb_amxkey = NULL; 1018 } 1019 1020 return (0); 1021 } 1022 1023 int 1024 tcp_signature_tdb_input(m, tdbp, skip, protoff) 1025 struct mbuf *m; 1026 struct tdb *tdbp; 1027 int skip, protoff; 1028 { 1029 return (0); 1030 } 1031 1032 int 1033 tcp_signature_tdb_output(m, tdbp, mp, skip, protoff) 1034 struct mbuf *m; 1035 struct tdb *tdbp; 1036 struct mbuf **mp; 1037 int skip, protoff; 1038 { 1039 return (EINVAL); 1040 } 1041 1042 int 1043 tcp_signature_apply(fstate, data, len) 1044 caddr_t fstate; 1045 caddr_t data; 1046 unsigned int len; 1047 { 1048 MD5Update((MD5_CTX *)fstate, (char *)data, len); 1049 return 0; 1050 } 1051 1052 int 1053 tcp_signature(struct tdb *tdb, int af, struct mbuf *m, struct tcphdr *th, 1054 int iphlen, int doswap, char *sig) 1055 { 1056 MD5_CTX ctx; 1057 int len; 1058 struct tcphdr th0; 1059 1060 MD5Init(&ctx); 1061 1062 switch(af) { 1063 case 0: 1064 #ifdef INET 1065 case AF_INET: { 1066 struct ippseudo ippseudo; 1067 struct ip *ip; 1068 1069 ip = mtod(m, struct ip *); 1070 1071 ippseudo.ippseudo_src = ip->ip_src; 1072 ippseudo.ippseudo_dst = ip->ip_dst; 1073 ippseudo.ippseudo_pad = 0; 1074 ippseudo.ippseudo_p = IPPROTO_TCP; 1075 ippseudo.ippseudo_len = htons(m->m_pkthdr.len - iphlen); 1076 1077 MD5Update(&ctx, (char *)&ippseudo, 1078 sizeof(struct ippseudo)); 1079 break; 1080 } 1081 #endif 1082 #ifdef INET6 1083 case AF_INET6: { 1084 struct ip6_hdr_pseudo ip6pseudo; 1085 struct ip6_hdr *ip6; 1086 1087 ip6 = mtod(m, struct ip6_hdr *); 1088 bzero(&ip6pseudo, sizeof(ip6pseudo)); 1089 ip6pseudo.ip6ph_src = ip6->ip6_src; 1090 ip6pseudo.ip6ph_dst = ip6->ip6_dst; 1091 in6_clearscope(&ip6pseudo.ip6ph_src); 1092 in6_clearscope(&ip6pseudo.ip6ph_dst); 1093 ip6pseudo.ip6ph_nxt = IPPROTO_TCP; 1094 ip6pseudo.ip6ph_len = htonl(m->m_pkthdr.len - iphlen); 1095 1096 MD5Update(&ctx, (char *)&ip6pseudo, 1097 sizeof(ip6pseudo)); 1098 break; 1099 } 1100 #endif 1101 } 1102 1103 th0 = *th; 1104 th0.th_sum = 0; 1105 1106 if (doswap) { 1107 HTONL(th0.th_seq); 1108 HTONL(th0.th_ack); 1109 HTONS(th0.th_win); 1110 HTONS(th0.th_urp); 1111 } 1112 MD5Update(&ctx, (char *)&th0, sizeof(th0)); 1113 1114 len = m->m_pkthdr.len - iphlen - th->th_off * sizeof(uint32_t); 1115 1116 if (len > 0 && 1117 m_apply(m, iphlen + th->th_off * sizeof(uint32_t), len, 1118 tcp_signature_apply, (caddr_t)&ctx)) 1119 return (-1); 1120 1121 MD5Update(&ctx, tdb->tdb_amxkey, tdb->tdb_amxkeylen); 1122 MD5Final(sig, &ctx); 1123 1124 return (0); 1125 } 1126 #endif /* TCP_SIGNATURE */ 1127