1 /* $OpenBSD: tcp_subr.c,v 1.165 2017/06/26 09:32:32 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 94 #ifdef INET6 95 #include <netinet6/ip6protosw.h> 96 #endif /* INET6 */ 97 98 #include <crypto/md5.h> 99 #include <crypto/sha2.h> 100 101 /* patchable/settable parameters for tcp */ 102 int tcp_mssdflt = TCP_MSS; 103 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 104 105 /* values controllable via sysctl */ 106 int tcp_do_rfc1323 = 1; 107 #ifdef TCP_SACK 108 int tcp_do_sack = 1; /* RFC 2018 selective ACKs */ 109 #endif 110 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ 111 #ifdef TCP_ECN 112 int tcp_do_ecn = 0; /* RFC3168 ECN enabled/disabled? */ 113 #endif 114 int tcp_do_rfc3390 = 2; /* Increase TCP's Initial Window to 10*mss */ 115 116 u_int32_t tcp_now = 1; 117 118 #ifndef TCB_INITIAL_HASH_SIZE 119 #define TCB_INITIAL_HASH_SIZE 128 120 #endif 121 122 int tcp_reass_limit = NMBCLUSTERS / 8; /* hardlimit for tcpqe_pool */ 123 #ifdef TCP_SACK 124 int tcp_sackhole_limit = 32*1024; /* hardlimit for sackhl_pool */ 125 #endif 126 127 struct pool tcpcb_pool; 128 struct pool tcpqe_pool; 129 #ifdef TCP_SACK 130 struct pool sackhl_pool; 131 #endif 132 133 struct cpumem *tcpcounters; /* tcp statistics */ 134 tcp_seq tcp_iss; 135 136 /* 137 * Tcp initialization 138 */ 139 void 140 tcp_init(void) 141 { 142 tcp_iss = 1; /* wrong */ 143 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, IPL_SOFTNET, 0, 144 "tcpcb", NULL); 145 pool_init(&tcpqe_pool, sizeof(struct tcpqent), 0, IPL_SOFTNET, 0, 146 "tcpqe", NULL); 147 pool_sethardlimit(&tcpqe_pool, tcp_reass_limit, NULL, 0); 148 #ifdef TCP_SACK 149 pool_init(&sackhl_pool, sizeof(struct sackhole), 0, IPL_SOFTNET, 0, 150 "sackhl", NULL); 151 pool_sethardlimit(&sackhl_pool, tcp_sackhole_limit, NULL, 0); 152 #endif /* TCP_SACK */ 153 in_pcbinit(&tcbtable, TCB_INITIAL_HASH_SIZE); 154 tcpcounters = counters_alloc(tcps_ncounters); 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 struct socket *so = tp->t_inpcb->inp_socket; 309 win = sbspace(so, &so->so_rcv); 310 /* 311 * If this is called with an unconnected 312 * socket/tp/pcb (tp->pf is 0), we lose. 313 */ 314 af = tp->pf; 315 } else 316 af = (((struct ip *)template)->ip_v == 6) ? AF_INET6 : AF_INET; 317 318 m = m_gethdr(M_DONTWAIT, MT_HEADER); 319 if (m == NULL) 320 return; 321 m->m_data += max_linkhdr; 322 tlen = 0; 323 324 #define xchg(a,b,type) do { type t; t=a; a=b; b=t; } while (0) 325 switch (af) { 326 #ifdef INET6 327 case AF_INET6: 328 ip6 = mtod(m, struct ip6_hdr *); 329 th = (struct tcphdr *)(ip6 + 1); 330 tlen = sizeof(*ip6) + sizeof(*th); 331 if (th0) { 332 bcopy(template, ip6, sizeof(*ip6)); 333 bcopy(th0, th, sizeof(*th)); 334 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 335 } else { 336 bcopy(template, ip6, tlen); 337 } 338 break; 339 #endif /* INET6 */ 340 case AF_INET: 341 ip = mtod(m, struct ip *); 342 th = (struct tcphdr *)(ip + 1); 343 tlen = sizeof(*ip) + sizeof(*th); 344 if (th0) { 345 bcopy(template, ip, sizeof(*ip)); 346 bcopy(th0, th, sizeof(*th)); 347 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, u_int32_t); 348 } else { 349 bcopy(template, ip, tlen); 350 } 351 break; 352 } 353 if (th0) 354 xchg(th->th_dport, th->th_sport, u_int16_t); 355 else 356 flags = TH_ACK; 357 #undef xchg 358 359 th->th_seq = htonl(seq); 360 th->th_ack = htonl(ack); 361 th->th_x2 = 0; 362 th->th_off = sizeof (struct tcphdr) >> 2; 363 th->th_flags = flags; 364 if (tp) 365 win >>= tp->rcv_scale; 366 if (win > TCP_MAXWIN) 367 win = TCP_MAXWIN; 368 th->th_win = htons((u_int16_t)win); 369 th->th_urp = 0; 370 371 if (tp && (tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 372 (flags & TH_RST) == 0 && (tp->t_flags & TF_RCVD_TSTMP)) { 373 u_int32_t *lp = (u_int32_t *)(th + 1); 374 /* Form timestamp option as shown in appendix A of RFC 1323. */ 375 *lp++ = htonl(TCPOPT_TSTAMP_HDR); 376 *lp++ = htonl(tcp_now + tp->ts_modulate); 377 *lp = htonl(tp->ts_recent); 378 tlen += TCPOLEN_TSTAMP_APPA; 379 th->th_off = (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_APPA) >> 2; 380 } 381 382 m->m_len = tlen; 383 m->m_pkthdr.len = tlen; 384 m->m_pkthdr.ph_ifidx = 0; 385 m->m_pkthdr.csum_flags |= M_TCP_CSUM_OUT; 386 387 /* force routing table */ 388 if (tp) 389 m->m_pkthdr.ph_rtableid = tp->t_inpcb->inp_rtableid; 390 else 391 m->m_pkthdr.ph_rtableid = rtableid; 392 393 switch (af) { 394 #ifdef INET6 395 case AF_INET6: 396 ip6->ip6_flow = htonl(0x60000000); 397 ip6->ip6_nxt = IPPROTO_TCP; 398 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL); /*XXX*/ 399 ip6->ip6_plen = tlen - sizeof(struct ip6_hdr); 400 ip6->ip6_plen = htons(ip6->ip6_plen); 401 ip6_output(m, tp ? tp->t_inpcb->inp_outputopts6 : NULL, 402 tp ? &tp->t_inpcb->inp_route6 : NULL, 403 0, NULL, 404 tp ? tp->t_inpcb : NULL); 405 break; 406 #endif /* INET6 */ 407 case AF_INET: 408 ip->ip_len = htons(tlen); 409 ip->ip_ttl = ip_defttl; 410 ip->ip_tos = 0; 411 ip_output(m, NULL, 412 tp ? &tp->t_inpcb->inp_route : NULL, 413 ip_mtudisc ? IP_MTUDISC : 0, NULL, 414 tp ? tp->t_inpcb : NULL, 0); 415 break; 416 } 417 } 418 419 /* 420 * Create a new TCP control block, making an 421 * empty reassembly queue and hooking it to the argument 422 * protocol control block. 423 */ 424 struct tcpcb * 425 tcp_newtcpcb(struct inpcb *inp) 426 { 427 struct tcpcb *tp; 428 int i; 429 430 tp = pool_get(&tcpcb_pool, PR_NOWAIT|PR_ZERO); 431 if (tp == NULL) 432 return (NULL); 433 TAILQ_INIT(&tp->t_segq); 434 tp->t_maxseg = tcp_mssdflt; 435 tp->t_maxopd = 0; 436 437 TCP_INIT_DELACK(tp); 438 for (i = 0; i < TCPT_NTIMERS; i++) 439 TCP_TIMER_INIT(tp, i); 440 timeout_set(&tp->t_reap_to, tcp_reaper, tp); 441 442 #ifdef TCP_SACK 443 tp->sack_enable = tcp_do_sack; 444 #endif 445 tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; 446 tp->t_inpcb = inp; 447 /* 448 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 449 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 450 * reasonable initial retransmit time. 451 */ 452 tp->t_srtt = TCPTV_SRTTBASE; 453 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << 454 (TCP_RTTVAR_SHIFT + TCP_RTT_BASE_SHIFT - 1); 455 tp->t_rttmin = TCPTV_MIN; 456 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 457 TCPTV_MIN, TCPTV_REXMTMAX); 458 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 459 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 460 461 tp->t_pmtud_mtu_sent = 0; 462 tp->t_pmtud_mss_acked = 0; 463 464 #ifdef INET6 465 /* we disallow IPv4 mapped address completely. */ 466 if ((inp->inp_flags & INP_IPV6) == 0) 467 tp->pf = PF_INET; 468 else 469 tp->pf = PF_INET6; 470 #else 471 tp->pf = PF_INET; 472 #endif 473 474 #ifdef INET6 475 if (inp->inp_flags & INP_IPV6) 476 inp->inp_ipv6.ip6_hlim = ip6_defhlim; 477 else 478 #endif /* INET6 */ 479 inp->inp_ip.ip_ttl = ip_defttl; 480 481 inp->inp_ppcb = (caddr_t)tp; 482 return (tp); 483 } 484 485 /* 486 * Drop a TCP connection, reporting 487 * the specified error. If connection is synchronized, 488 * then send a RST to peer. 489 */ 490 struct tcpcb * 491 tcp_drop(struct tcpcb *tp, int errno) 492 { 493 struct socket *so = tp->t_inpcb->inp_socket; 494 495 if (TCPS_HAVERCVDSYN(tp->t_state)) { 496 tp->t_state = TCPS_CLOSED; 497 (void) tcp_output(tp); 498 tcpstat_inc(tcps_drops); 499 } else 500 tcpstat_inc(tcps_conndrops); 501 if (errno == ETIMEDOUT && tp->t_softerror) 502 errno = tp->t_softerror; 503 so->so_error = errno; 504 return (tcp_close(tp)); 505 } 506 507 /* 508 * Close a TCP control block: 509 * discard all space held by the tcp 510 * discard internet protocol block 511 * wake up any sleepers 512 */ 513 struct tcpcb * 514 tcp_close(struct tcpcb *tp) 515 { 516 struct inpcb *inp = tp->t_inpcb; 517 struct socket *so = inp->inp_socket; 518 #ifdef TCP_SACK 519 struct sackhole *p, *q; 520 #endif 521 522 /* free the reassembly queue, if any */ 523 tcp_freeq(tp); 524 525 tcp_canceltimers(tp); 526 TCP_CLEAR_DELACK(tp); 527 syn_cache_cleanup(tp); 528 529 #ifdef TCP_SACK 530 /* Free SACK holes. */ 531 q = p = tp->snd_holes; 532 while (p != 0) { 533 q = p->next; 534 pool_put(&sackhl_pool, p); 535 p = q; 536 } 537 #endif 538 m_free(tp->t_template); 539 540 tp->t_flags |= TF_DEAD; 541 timeout_add(&tp->t_reap_to, 0); 542 543 inp->inp_ppcb = 0; 544 soisdisconnected(so); 545 in_pcbdetach(inp); 546 return (NULL); 547 } 548 549 void 550 tcp_reaper(void *arg) 551 { 552 struct tcpcb *tp = arg; 553 554 pool_put(&tcpcb_pool, tp); 555 tcpstat_inc(tcps_closed); 556 } 557 558 int 559 tcp_freeq(struct tcpcb *tp) 560 { 561 struct tcpqent *qe; 562 int rv = 0; 563 564 while ((qe = TAILQ_FIRST(&tp->t_segq)) != NULL) { 565 TAILQ_REMOVE(&tp->t_segq, qe, tcpqe_q); 566 m_freem(qe->tcpqe_m); 567 pool_put(&tcpqe_pool, qe); 568 rv = 1; 569 } 570 return (rv); 571 } 572 573 /* 574 * Compute proper scaling value for receiver window from buffer space 575 */ 576 577 void 578 tcp_rscale(struct tcpcb *tp, u_long hiwat) 579 { 580 tp->request_r_scale = 0; 581 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 582 TCP_MAXWIN << tp->request_r_scale < hiwat) 583 tp->request_r_scale++; 584 } 585 586 /* 587 * Notify a tcp user of an asynchronous error; 588 * store error as soft error, but wake up user 589 * (for now, won't do anything until can select for soft error). 590 */ 591 void 592 tcp_notify(struct inpcb *inp, int error) 593 { 594 struct tcpcb *tp = intotcpcb(inp); 595 struct socket *so = inp->inp_socket; 596 597 /* 598 * Ignore some errors if we are hooked up. 599 * If connection hasn't completed, has retransmitted several times, 600 * and receives a second error, give up now. This is better 601 * than waiting a long time to establish a connection that 602 * can never complete. 603 */ 604 if (tp->t_state == TCPS_ESTABLISHED && 605 (error == EHOSTUNREACH || error == ENETUNREACH || 606 error == EHOSTDOWN)) { 607 return; 608 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 609 tp->t_rxtshift > 3 && tp->t_softerror) 610 so->so_error = error; 611 else 612 tp->t_softerror = error; 613 wakeup((caddr_t) &so->so_timeo); 614 sorwakeup(so); 615 sowwakeup(so); 616 } 617 618 #ifdef INET6 619 void 620 tcp6_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *d) 621 { 622 struct tcphdr th; 623 struct tcpcb *tp; 624 void (*notify)(struct inpcb *, int) = tcp_notify; 625 struct ip6_hdr *ip6; 626 const struct sockaddr_in6 *sa6_src = NULL; 627 struct sockaddr_in6 *sa6 = satosin6(sa); 628 struct inpcb *inp; 629 struct mbuf *m; 630 tcp_seq seq; 631 int off; 632 struct { 633 u_int16_t th_sport; 634 u_int16_t th_dport; 635 u_int32_t th_seq; 636 } *thp; 637 638 CTASSERT(sizeof(*thp) <= sizeof(th)); 639 if (sa->sa_family != AF_INET6 || 640 sa->sa_len != sizeof(struct sockaddr_in6) || 641 IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) || 642 IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) 643 return; 644 if ((unsigned)cmd >= PRC_NCMDS) 645 return; 646 else if (cmd == PRC_QUENCH) { 647 /* 648 * Don't honor ICMP Source Quench messages meant for 649 * TCP connections. 650 */ 651 /* XXX there's no PRC_QUENCH in IPv6 */ 652 return; 653 } else if (PRC_IS_REDIRECT(cmd)) 654 notify = in_rtchange, d = NULL; 655 else if (cmd == PRC_MSGSIZE) 656 ; /* special code is present, see below */ 657 else if (cmd == PRC_HOSTDEAD) 658 d = NULL; 659 else if (inet6ctlerrmap[cmd] == 0) 660 return; 661 662 /* if the parameter is from icmp6, decode it. */ 663 if (d != NULL) { 664 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 665 m = ip6cp->ip6c_m; 666 ip6 = ip6cp->ip6c_ip6; 667 off = ip6cp->ip6c_off; 668 sa6_src = ip6cp->ip6c_src; 669 } else { 670 m = NULL; 671 ip6 = NULL; 672 sa6_src = &sa6_any; 673 } 674 675 if (ip6) { 676 /* 677 * XXX: We assume that when ip6 is non NULL, 678 * M and OFF are valid. 679 */ 680 681 /* check if we can safely examine src and dst ports */ 682 if (m->m_pkthdr.len < off + sizeof(*thp)) 683 return; 684 685 bzero(&th, sizeof(th)); 686 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 687 688 /* 689 * Check to see if we have a valid TCP connection 690 * corresponding to the address in the ICMPv6 message 691 * payload. 692 */ 693 inp = in6_pcbhashlookup(&tcbtable, &sa6->sin6_addr, 694 th.th_dport, &sa6_src->sin6_addr, th.th_sport, rdomain); 695 if (cmd == PRC_MSGSIZE) { 696 /* 697 * Depending on the value of "valid" and routing table 698 * size (mtudisc_{hi,lo}wat), we will: 699 * - recalcurate the new MTU and create the 700 * corresponding routing entry, or 701 * - ignore the MTU change notification. 702 */ 703 icmp6_mtudisc_update((struct ip6ctlparam *)d, inp != NULL); 704 return; 705 } 706 if (inp) { 707 seq = ntohl(th.th_seq); 708 if (inp->inp_socket && 709 (tp = intotcpcb(inp)) && 710 SEQ_GEQ(seq, tp->snd_una) && 711 SEQ_LT(seq, tp->snd_max)) 712 notify(inp, inet6ctlerrmap[cmd]); 713 } else if (inet6ctlerrmap[cmd] == EHOSTUNREACH || 714 inet6ctlerrmap[cmd] == ENETUNREACH || 715 inet6ctlerrmap[cmd] == EHOSTDOWN) 716 syn_cache_unreach((struct sockaddr *)sa6_src, 717 sa, &th, rdomain); 718 } else { 719 (void) in6_pcbnotify(&tcbtable, sa6, 0, 720 sa6_src, 0, rdomain, cmd, NULL, notify); 721 } 722 } 723 #endif 724 725 void 726 tcp_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *v) 727 { 728 struct ip *ip = v; 729 struct tcphdr *th; 730 struct tcpcb *tp; 731 struct inpcb *inp; 732 struct in_addr faddr; 733 tcp_seq seq; 734 u_int mtu; 735 void (*notify)(struct inpcb *, int) = tcp_notify; 736 int errno; 737 738 if (sa->sa_family != AF_INET) 739 return; 740 faddr = satosin(sa)->sin_addr; 741 if (faddr.s_addr == INADDR_ANY) 742 return; 743 744 if ((unsigned)cmd >= PRC_NCMDS) 745 return; 746 errno = inetctlerrmap[cmd]; 747 if (cmd == PRC_QUENCH) 748 /* 749 * Don't honor ICMP Source Quench messages meant for 750 * TCP connections. 751 */ 752 return; 753 else if (PRC_IS_REDIRECT(cmd)) 754 notify = in_rtchange, ip = 0; 755 else if (cmd == PRC_MSGSIZE && ip_mtudisc && ip) { 756 /* 757 * Verify that the packet in the icmp payload refers 758 * to an existing TCP connection. 759 */ 760 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 761 seq = ntohl(th->th_seq); 762 inp = in_pcbhashlookup(&tcbtable, 763 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 764 rdomain); 765 if (inp && (tp = intotcpcb(inp)) && 766 SEQ_GEQ(seq, tp->snd_una) && 767 SEQ_LT(seq, tp->snd_max)) { 768 struct icmp *icp; 769 icp = (struct icmp *)((caddr_t)ip - 770 offsetof(struct icmp, icmp_ip)); 771 772 /* 773 * If the ICMP message advertises a Next-Hop MTU 774 * equal or larger than the maximum packet size we have 775 * ever sent, drop the message. 776 */ 777 mtu = (u_int)ntohs(icp->icmp_nextmtu); 778 if (mtu >= tp->t_pmtud_mtu_sent) 779 return; 780 if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) { 781 /* 782 * Calculate new MTU, and create corresponding 783 * route (traditional PMTUD). 784 */ 785 tp->t_flags &= ~TF_PMTUD_PEND; 786 icmp_mtudisc(icp, inp->inp_rtableid); 787 } else { 788 /* 789 * Record the information got in the ICMP 790 * message; act on it later. 791 * If we had already recorded an ICMP message, 792 * replace the old one only if the new message 793 * refers to an older TCP segment 794 */ 795 if (tp->t_flags & TF_PMTUD_PEND) { 796 if (SEQ_LT(tp->t_pmtud_th_seq, seq)) 797 return; 798 } else 799 tp->t_flags |= TF_PMTUD_PEND; 800 tp->t_pmtud_th_seq = seq; 801 tp->t_pmtud_nextmtu = icp->icmp_nextmtu; 802 tp->t_pmtud_ip_len = icp->icmp_ip.ip_len; 803 tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl; 804 return; 805 } 806 } else { 807 /* ignore if we don't have a matching connection */ 808 return; 809 } 810 notify = tcp_mtudisc, ip = 0; 811 } else if (cmd == PRC_MTUINC) 812 notify = tcp_mtudisc_increase, ip = 0; 813 else if (cmd == PRC_HOSTDEAD) 814 ip = 0; 815 else if (errno == 0) 816 return; 817 818 if (ip) { 819 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 820 inp = in_pcbhashlookup(&tcbtable, 821 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 822 rdomain); 823 if (inp) { 824 seq = ntohl(th->th_seq); 825 if (inp->inp_socket && 826 (tp = intotcpcb(inp)) && 827 SEQ_GEQ(seq, tp->snd_una) && 828 SEQ_LT(seq, tp->snd_max)) 829 notify(inp, errno); 830 } else if (inetctlerrmap[cmd] == EHOSTUNREACH || 831 inetctlerrmap[cmd] == ENETUNREACH || 832 inetctlerrmap[cmd] == EHOSTDOWN) { 833 struct sockaddr_in sin; 834 835 bzero(&sin, sizeof(sin)); 836 sin.sin_len = sizeof(sin); 837 sin.sin_family = AF_INET; 838 sin.sin_port = th->th_sport; 839 sin.sin_addr = ip->ip_src; 840 syn_cache_unreach(sintosa(&sin), sa, th, rdomain); 841 } 842 } else 843 in_pcbnotifyall(&tcbtable, sa, rdomain, errno, notify); 844 } 845 846 847 #ifdef INET6 848 /* 849 * Path MTU Discovery handlers. 850 */ 851 void 852 tcp6_mtudisc_callback(struct sockaddr_in6 *sin6, u_int rdomain) 853 { 854 (void) in6_pcbnotify(&tcbtable, sin6, 0, 855 &sa6_any, 0, rdomain, PRC_MSGSIZE, NULL, tcp_mtudisc); 856 } 857 #endif /* INET6 */ 858 859 /* 860 * On receipt of path MTU corrections, flush old route and replace it 861 * with the new one. Retransmit all unacknowledged packets, to ensure 862 * that all packets will be received. 863 */ 864 void 865 tcp_mtudisc(struct inpcb *inp, int errno) 866 { 867 struct tcpcb *tp = intotcpcb(inp); 868 struct rtentry *rt = in_pcbrtentry(inp); 869 int change = 0; 870 871 if (tp != 0) { 872 int orig_maxseg = tp->t_maxseg; 873 if (rt != 0) { 874 /* 875 * If this was not a host route, remove and realloc. 876 */ 877 if ((rt->rt_flags & RTF_HOST) == 0) { 878 in_rtchange(inp, errno); 879 if ((rt = in_pcbrtentry(inp)) == 0) 880 return; 881 } 882 if (orig_maxseg != tp->t_maxseg || 883 (rt->rt_locks & RTV_MTU)) 884 change = 1; 885 } 886 tcp_mss(tp, -1); 887 888 /* 889 * Resend unacknowledged packets 890 */ 891 tp->snd_nxt = tp->snd_una; 892 if (change || errno > 0) 893 tcp_output(tp); 894 } 895 } 896 897 void 898 tcp_mtudisc_increase(struct inpcb *inp, int errno) 899 { 900 struct tcpcb *tp = intotcpcb(inp); 901 struct rtentry *rt = in_pcbrtentry(inp); 902 903 if (tp != 0 && rt != 0) { 904 /* 905 * If this was a host route, remove and realloc. 906 */ 907 if (rt->rt_flags & RTF_HOST) 908 in_rtchange(inp, errno); 909 910 /* also takes care of congestion window */ 911 tcp_mss(tp, -1); 912 } 913 } 914 915 /* 916 * Generate new ISNs with a method based on RFC1948 917 */ 918 #define TCP_ISS_CONN_INC 4096 919 int tcp_secret_init; 920 u_char tcp_secret[16]; 921 SHA2_CTX tcp_secret_ctx; 922 923 void 924 tcp_set_iss_tsm(struct tcpcb *tp) 925 { 926 SHA2_CTX ctx; 927 union { 928 uint8_t bytes[SHA512_DIGEST_LENGTH]; 929 uint32_t words[2]; 930 } digest; 931 u_int rdomain = rtable_l2(tp->t_inpcb->inp_rtableid); 932 933 if (tcp_secret_init == 0) { 934 arc4random_buf(tcp_secret, sizeof(tcp_secret)); 935 SHA512Init(&tcp_secret_ctx); 936 SHA512Update(&tcp_secret_ctx, tcp_secret, sizeof(tcp_secret)); 937 tcp_secret_init = 1; 938 } 939 ctx = tcp_secret_ctx; 940 SHA512Update(&ctx, &rdomain, sizeof(rdomain)); 941 SHA512Update(&ctx, &tp->t_inpcb->inp_lport, sizeof(u_short)); 942 SHA512Update(&ctx, &tp->t_inpcb->inp_fport, sizeof(u_short)); 943 if (tp->pf == AF_INET6) { 944 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr6, 945 sizeof(struct in6_addr)); 946 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr6, 947 sizeof(struct in6_addr)); 948 } else { 949 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr, 950 sizeof(struct in_addr)); 951 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr, 952 sizeof(struct in_addr)); 953 } 954 SHA512Final(digest.bytes, &ctx); 955 tcp_iss += TCP_ISS_CONN_INC; 956 tp->iss = digest.words[0] + tcp_iss; 957 tp->ts_modulate = digest.words[1]; 958 } 959 960 #ifdef TCP_SIGNATURE 961 int 962 tcp_signature_tdb_attach(void) 963 { 964 return (0); 965 } 966 967 int 968 tcp_signature_tdb_init(struct tdb *tdbp, struct xformsw *xsp, 969 struct ipsecinit *ii) 970 { 971 if ((ii->ii_authkeylen < 1) || (ii->ii_authkeylen > 80)) 972 return (EINVAL); 973 974 tdbp->tdb_amxkey = malloc(ii->ii_authkeylen, M_XDATA, M_NOWAIT); 975 if (tdbp->tdb_amxkey == NULL) 976 return (ENOMEM); 977 bcopy(ii->ii_authkey, tdbp->tdb_amxkey, ii->ii_authkeylen); 978 tdbp->tdb_amxkeylen = ii->ii_authkeylen; 979 980 return (0); 981 } 982 983 int 984 tcp_signature_tdb_zeroize(struct tdb *tdbp) 985 { 986 if (tdbp->tdb_amxkey) { 987 explicit_bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); 988 free(tdbp->tdb_amxkey, M_XDATA, 0); 989 tdbp->tdb_amxkey = NULL; 990 } 991 992 return (0); 993 } 994 995 int 996 tcp_signature_tdb_input(struct mbuf *m, struct tdb *tdbp, int skip, int protoff) 997 { 998 return (0); 999 } 1000 1001 int 1002 tcp_signature_tdb_output(struct mbuf *m, struct tdb *tdbp, struct mbuf **mp, 1003 int skip, int protoff) 1004 { 1005 return (EINVAL); 1006 } 1007 1008 int 1009 tcp_signature_apply(caddr_t fstate, caddr_t data, unsigned int len) 1010 { 1011 MD5Update((MD5_CTX *)fstate, (char *)data, len); 1012 return 0; 1013 } 1014 1015 int 1016 tcp_signature(struct tdb *tdb, int af, struct mbuf *m, struct tcphdr *th, 1017 int iphlen, int doswap, char *sig) 1018 { 1019 MD5_CTX ctx; 1020 int len; 1021 struct tcphdr th0; 1022 1023 MD5Init(&ctx); 1024 1025 switch(af) { 1026 case 0: 1027 case AF_INET: { 1028 struct ippseudo ippseudo; 1029 struct ip *ip; 1030 1031 ip = mtod(m, struct ip *); 1032 1033 ippseudo.ippseudo_src = ip->ip_src; 1034 ippseudo.ippseudo_dst = ip->ip_dst; 1035 ippseudo.ippseudo_pad = 0; 1036 ippseudo.ippseudo_p = IPPROTO_TCP; 1037 ippseudo.ippseudo_len = htons(m->m_pkthdr.len - iphlen); 1038 1039 MD5Update(&ctx, (char *)&ippseudo, 1040 sizeof(struct ippseudo)); 1041 break; 1042 } 1043 #ifdef INET6 1044 case AF_INET6: { 1045 struct ip6_hdr_pseudo ip6pseudo; 1046 struct ip6_hdr *ip6; 1047 1048 ip6 = mtod(m, struct ip6_hdr *); 1049 bzero(&ip6pseudo, sizeof(ip6pseudo)); 1050 ip6pseudo.ip6ph_src = ip6->ip6_src; 1051 ip6pseudo.ip6ph_dst = ip6->ip6_dst; 1052 in6_clearscope(&ip6pseudo.ip6ph_src); 1053 in6_clearscope(&ip6pseudo.ip6ph_dst); 1054 ip6pseudo.ip6ph_nxt = IPPROTO_TCP; 1055 ip6pseudo.ip6ph_len = htonl(m->m_pkthdr.len - iphlen); 1056 1057 MD5Update(&ctx, (char *)&ip6pseudo, 1058 sizeof(ip6pseudo)); 1059 break; 1060 } 1061 #endif 1062 } 1063 1064 th0 = *th; 1065 th0.th_sum = 0; 1066 1067 if (doswap) { 1068 th0.th_seq = htonl(th0.th_seq); 1069 th0.th_ack = htonl(th0.th_ack); 1070 th0.th_win = htons(th0.th_win); 1071 th0.th_urp = htons(th0.th_urp); 1072 } 1073 MD5Update(&ctx, (char *)&th0, sizeof(th0)); 1074 1075 len = m->m_pkthdr.len - iphlen - th->th_off * sizeof(uint32_t); 1076 1077 if (len > 0 && 1078 m_apply(m, iphlen + th->th_off * sizeof(uint32_t), len, 1079 tcp_signature_apply, (caddr_t)&ctx)) 1080 return (-1); 1081 1082 MD5Update(&ctx, tdb->tdb_amxkey, tdb->tdb_amxkeylen); 1083 MD5Final(sig, &ctx); 1084 1085 return (0); 1086 } 1087 #endif /* TCP_SIGNATURE */ 1088