1 /* $OpenBSD: tcp_subr.c,v 1.142 2015/05/13 10:42:46 jsg 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 /* syn hash parameters */ 124 #define TCP_SYN_HASH_SIZE 293 125 #define TCP_SYN_BUCKET_SIZE 35 126 int tcp_syn_cache_size = TCP_SYN_HASH_SIZE; 127 int tcp_syn_cache_limit = TCP_SYN_HASH_SIZE*TCP_SYN_BUCKET_SIZE; 128 int tcp_syn_bucket_limit = 3*TCP_SYN_BUCKET_SIZE; 129 struct syn_cache_head tcp_syn_cache[TCP_SYN_HASH_SIZE]; 130 131 int tcp_reass_limit = NMBCLUSTERS / 2; /* hardlimit for tcpqe_pool */ 132 #ifdef TCP_SACK 133 int tcp_sackhole_limit = 32*1024; /* hardlimit for sackhl_pool */ 134 #endif 135 136 struct pool tcpcb_pool; 137 struct pool tcpqe_pool; 138 #ifdef TCP_SACK 139 struct pool sackhl_pool; 140 #endif 141 142 struct tcpstat tcpstat; /* tcp statistics */ 143 tcp_seq tcp_iss; 144 145 /* 146 * Tcp initialization 147 */ 148 void 149 tcp_init() 150 { 151 tcp_iss = 1; /* wrong */ 152 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcb", NULL); 153 pool_init(&tcpqe_pool, sizeof(struct tcpqent), 0, 0, 0, "tcpqe", NULL); 154 pool_sethardlimit(&tcpqe_pool, tcp_reass_limit, NULL, 0); 155 #ifdef TCP_SACK 156 pool_init(&sackhl_pool, sizeof(struct sackhole), 0, 0, 0, "sackhl", 157 NULL); 158 pool_sethardlimit(&sackhl_pool, tcp_sackhole_limit, NULL, 0); 159 #endif /* TCP_SACK */ 160 in_pcbinit(&tcbtable, TCB_INITIAL_HASH_SIZE); 161 162 #ifdef INET6 163 /* 164 * Since sizeof(struct ip6_hdr) > sizeof(struct ip), we 165 * do max length checks/computations only on the former. 166 */ 167 if (max_protohdr < (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))) 168 max_protohdr = (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)); 169 if ((max_linkhdr + sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) > 170 MHLEN) 171 panic("tcp_init"); 172 173 icmp6_mtudisc_callback_register(tcp6_mtudisc_callback); 174 #endif /* INET6 */ 175 176 /* Initialize the compressed state engine. */ 177 syn_cache_init(); 178 179 /* Initialize timer state. */ 180 tcp_timer_init(); 181 } 182 183 /* 184 * Create template to be used to send tcp packets on a connection. 185 * Call after host entry created, allocates an mbuf and fills 186 * in a skeletal tcp/ip header, minimizing the amount of work 187 * necessary when the connection is used. 188 * 189 * To support IPv6 in addition to IPv4 and considering that the sizes of 190 * the IPv4 and IPv6 headers are not the same, we now use a separate pointer 191 * for the TCP header. Also, we made the former tcpiphdr header pointer 192 * into just an IP overlay pointer, with casting as appropriate for v6. rja 193 */ 194 struct mbuf * 195 tcp_template(tp) 196 struct tcpcb *tp; 197 { 198 struct inpcb *inp = tp->t_inpcb; 199 struct mbuf *m; 200 struct tcphdr *th; 201 202 if ((m = tp->t_template) == 0) { 203 m = m_get(M_DONTWAIT, MT_HEADER); 204 if (m == NULL) 205 return (0); 206 207 switch (tp->pf) { 208 case 0: /*default to PF_INET*/ 209 case AF_INET: 210 m->m_len = sizeof(struct ip); 211 break; 212 #ifdef INET6 213 case AF_INET6: 214 m->m_len = sizeof(struct ip6_hdr); 215 break; 216 #endif /* INET6 */ 217 } 218 m->m_len += sizeof (struct tcphdr); 219 220 /* 221 * The link header, network header, TCP header, and TCP options 222 * all must fit in this mbuf. For now, assume the worst case of 223 * TCP options size. Eventually, compute this from tp flags. 224 */ 225 if (m->m_len + MAX_TCPOPTLEN + max_linkhdr >= MHLEN) { 226 MCLGET(m, M_DONTWAIT); 227 if ((m->m_flags & M_EXT) == 0) { 228 m_free(m); 229 return (0); 230 } 231 } 232 } 233 234 switch(tp->pf) { 235 case AF_INET: 236 { 237 struct ipovly *ipovly; 238 239 ipovly = mtod(m, struct ipovly *); 240 241 bzero(ipovly->ih_x1, sizeof ipovly->ih_x1); 242 ipovly->ih_pr = IPPROTO_TCP; 243 ipovly->ih_len = htons(sizeof (struct tcphdr)); 244 ipovly->ih_src = inp->inp_laddr; 245 ipovly->ih_dst = inp->inp_faddr; 246 247 th = (struct tcphdr *)(mtod(m, caddr_t) + 248 sizeof(struct ip)); 249 } 250 break; 251 #ifdef INET6 252 case AF_INET6: 253 { 254 struct ip6_hdr *ip6; 255 256 ip6 = mtod(m, struct ip6_hdr *); 257 258 ip6->ip6_src = inp->inp_laddr6; 259 ip6->ip6_dst = inp->inp_faddr6; 260 ip6->ip6_flow = htonl(0x60000000) | 261 (inp->inp_flowinfo & IPV6_FLOWLABEL_MASK); 262 263 ip6->ip6_nxt = IPPROTO_TCP; 264 ip6->ip6_plen = htons(sizeof(struct tcphdr)); /*XXX*/ 265 ip6->ip6_hlim = in6_selecthlim(inp, NULL); /*XXX*/ 266 267 th = (struct tcphdr *)(mtod(m, caddr_t) + 268 sizeof(struct ip6_hdr)); 269 } 270 break; 271 #endif /* INET6 */ 272 } 273 274 th->th_sport = inp->inp_lport; 275 th->th_dport = inp->inp_fport; 276 th->th_seq = 0; 277 th->th_ack = 0; 278 th->th_x2 = 0; 279 th->th_off = 5; 280 th->th_flags = 0; 281 th->th_win = 0; 282 th->th_urp = 0; 283 th->th_sum = 0; 284 return (m); 285 } 286 287 /* 288 * Send a single message to the TCP at address specified by 289 * the given TCP/IP header. If m == 0, then we make a copy 290 * of the tcpiphdr at ti and send directly to the addressed host. 291 * This is used to force keep alive messages out using the TCP 292 * template for a connection tp->t_template. If flags are given 293 * then we send a message back to the TCP which originated the 294 * segment ti, and discard the mbuf containing it and any other 295 * attached mbufs. 296 * 297 * In any case the ack and sequence number of the transmitted 298 * segment are as specified by the parameters. 299 */ 300 void 301 tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0, 302 tcp_seq ack, tcp_seq seq, int flags, u_int rtableid) 303 { 304 int tlen; 305 int win = 0; 306 struct mbuf *m = NULL; 307 struct route *ro = NULL; 308 struct tcphdr *th; 309 struct ip *ip; 310 #ifdef INET6 311 struct ip6_hdr *ip6; 312 #endif 313 int af; /* af on wire */ 314 315 if (tp) { 316 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 317 /* 318 * If this is called with an unconnected 319 * socket/tp/pcb (tp->pf is 0), we lose. 320 */ 321 af = tp->pf; 322 323 /* 324 * The route/route6 distinction is meaningless 325 * unless you're allocating space or passing parameters. 326 */ 327 ro = &tp->t_inpcb->inp_route; 328 } else 329 af = (((struct ip *)template)->ip_v == 6) ? AF_INET6 : AF_INET; 330 331 m = m_gethdr(M_DONTWAIT, MT_HEADER); 332 if (m == NULL) 333 return; 334 m->m_data += max_linkhdr; 335 tlen = 0; 336 337 #define xchg(a,b,type) do { type t; t=a; a=b; b=t; } while (0) 338 switch (af) { 339 #ifdef INET6 340 case AF_INET6: 341 ip6 = mtod(m, struct ip6_hdr *); 342 th = (struct tcphdr *)(ip6 + 1); 343 tlen = sizeof(*ip6) + sizeof(*th); 344 if (th0) { 345 bcopy(template, ip6, sizeof(*ip6)); 346 bcopy(th0, th, sizeof(*th)); 347 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 348 } else { 349 bcopy(template, ip6, tlen); 350 } 351 break; 352 #endif /* INET6 */ 353 case AF_INET: 354 ip = mtod(m, struct ip *); 355 th = (struct tcphdr *)(ip + 1); 356 tlen = sizeof(*ip) + sizeof(*th); 357 if (th0) { 358 bcopy(template, ip, sizeof(*ip)); 359 bcopy(th0, th, sizeof(*th)); 360 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, u_int32_t); 361 } else { 362 bcopy(template, ip, tlen); 363 } 364 break; 365 } 366 if (th0) 367 xchg(th->th_dport, th->th_sport, u_int16_t); 368 else 369 flags = TH_ACK; 370 #undef xchg 371 372 th->th_seq = htonl(seq); 373 th->th_ack = htonl(ack); 374 th->th_x2 = 0; 375 th->th_off = sizeof (struct tcphdr) >> 2; 376 th->th_flags = flags; 377 if (tp) 378 win >>= tp->rcv_scale; 379 if (win > TCP_MAXWIN) 380 win = TCP_MAXWIN; 381 th->th_win = htons((u_int16_t)win); 382 th->th_urp = 0; 383 384 if (tp && (tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 385 (flags & TH_RST) == 0 && (tp->t_flags & TF_RCVD_TSTMP)) { 386 u_int32_t *lp = (u_int32_t *)(th + 1); 387 /* Form timestamp option as shown in appendix A of RFC 1323. */ 388 *lp++ = htonl(TCPOPT_TSTAMP_HDR); 389 *lp++ = htonl(tcp_now + tp->ts_modulate); 390 *lp = htonl(tp->ts_recent); 391 tlen += TCPOLEN_TSTAMP_APPA; 392 th->th_off = (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_APPA) >> 2; 393 } 394 395 m->m_len = tlen; 396 m->m_pkthdr.len = tlen; 397 m->m_pkthdr.rcvif = (struct ifnet *) 0; 398 m->m_pkthdr.csum_flags |= M_TCP_CSUM_OUT; 399 400 /* force routing table */ 401 if (tp) 402 m->m_pkthdr.ph_rtableid = tp->t_inpcb->inp_rtableid; 403 else 404 m->m_pkthdr.ph_rtableid = rtableid; 405 406 switch (af) { 407 #ifdef INET6 408 case AF_INET6: 409 ip6->ip6_flow = htonl(0x60000000); 410 ip6->ip6_nxt = IPPROTO_TCP; 411 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, NULL); /*XXX*/ 412 ip6->ip6_plen = tlen - sizeof(struct ip6_hdr); 413 HTONS(ip6->ip6_plen); 414 ip6_output(m, tp ? tp->t_inpcb->inp_outputopts6 : NULL, 415 (struct route_in6 *)ro, 0, NULL, NULL, 416 tp ? tp->t_inpcb : NULL); 417 break; 418 #endif /* INET6 */ 419 case AF_INET: 420 ip->ip_len = htons(tlen); 421 ip->ip_ttl = ip_defttl; 422 ip->ip_tos = 0; 423 ip_output(m, NULL, ro, ip_mtudisc ? IP_MTUDISC : 0, 424 NULL, tp ? tp->t_inpcb : NULL, 0); 425 } 426 } 427 428 /* 429 * Create a new TCP control block, making an 430 * empty reassembly queue and hooking it to the argument 431 * protocol control block. 432 */ 433 struct tcpcb * 434 tcp_newtcpcb(struct inpcb *inp) 435 { 436 struct tcpcb *tp; 437 int i; 438 439 tp = pool_get(&tcpcb_pool, PR_NOWAIT|PR_ZERO); 440 if (tp == NULL) 441 return (NULL); 442 TAILQ_INIT(&tp->t_segq); 443 tp->t_maxseg = tcp_mssdflt; 444 tp->t_maxopd = 0; 445 446 TCP_INIT_DELACK(tp); 447 for (i = 0; i < TCPT_NTIMERS; i++) 448 TCP_TIMER_INIT(tp, i); 449 timeout_set(&tp->t_reap_to, tcp_reaper, tp); 450 451 #ifdef TCP_SACK 452 tp->sack_enable = tcp_do_sack; 453 #endif 454 tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; 455 tp->t_inpcb = inp; 456 /* 457 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 458 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 459 * reasonable initial retransmit time. 460 */ 461 tp->t_srtt = TCPTV_SRTTBASE; 462 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << 463 (TCP_RTTVAR_SHIFT + TCP_RTT_BASE_SHIFT - 1); 464 tp->t_rttmin = TCPTV_MIN; 465 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 466 TCPTV_MIN, TCPTV_REXMTMAX); 467 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 468 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 469 470 tp->t_pmtud_mtu_sent = 0; 471 tp->t_pmtud_mss_acked = 0; 472 473 #ifdef INET6 474 /* we disallow IPv4 mapped address completely. */ 475 if ((inp->inp_flags & INP_IPV6) == 0) 476 tp->pf = PF_INET; 477 else 478 tp->pf = PF_INET6; 479 #else 480 tp->pf = PF_INET; 481 #endif 482 483 #ifdef INET6 484 if (inp->inp_flags & INP_IPV6) 485 inp->inp_ipv6.ip6_hlim = ip6_defhlim; 486 else 487 #endif /* INET6 */ 488 inp->inp_ip.ip_ttl = ip_defttl; 489 490 inp->inp_ppcb = (caddr_t)tp; 491 return (tp); 492 } 493 494 /* 495 * Drop a TCP connection, reporting 496 * the specified error. If connection is synchronized, 497 * then send a RST to peer. 498 */ 499 struct tcpcb * 500 tcp_drop(tp, errno) 501 struct tcpcb *tp; 502 int errno; 503 { 504 struct socket *so = tp->t_inpcb->inp_socket; 505 506 if (TCPS_HAVERCVDSYN(tp->t_state)) { 507 tp->t_state = TCPS_CLOSED; 508 (void) tcp_output(tp); 509 tcpstat.tcps_drops++; 510 } else 511 tcpstat.tcps_conndrops++; 512 if (errno == ETIMEDOUT && tp->t_softerror) 513 errno = tp->t_softerror; 514 so->so_error = errno; 515 return (tcp_close(tp)); 516 } 517 518 /* 519 * Close a TCP control block: 520 * discard all space held by the tcp 521 * discard internet protocol block 522 * wake up any sleepers 523 */ 524 struct tcpcb * 525 tcp_close(struct tcpcb *tp) 526 { 527 struct inpcb *inp = tp->t_inpcb; 528 struct socket *so = inp->inp_socket; 529 #ifdef TCP_SACK 530 struct sackhole *p, *q; 531 #endif 532 533 /* free the reassembly queue, if any */ 534 tcp_freeq(tp); 535 536 tcp_canceltimers(tp); 537 TCP_CLEAR_DELACK(tp); 538 syn_cache_cleanup(tp); 539 540 #ifdef TCP_SACK 541 /* Free SACK holes. */ 542 q = p = tp->snd_holes; 543 while (p != 0) { 544 q = p->next; 545 pool_put(&sackhl_pool, p); 546 p = q; 547 } 548 #endif 549 if (tp->t_template) 550 (void) m_free(tp->t_template); 551 552 tp->t_flags |= TF_DEAD; 553 timeout_add(&tp->t_reap_to, 0); 554 555 inp->inp_ppcb = 0; 556 soisdisconnected(so); 557 in_pcbdetach(inp); 558 return (NULL); 559 } 560 561 void 562 tcp_reaper(void *arg) 563 { 564 struct tcpcb *tp = arg; 565 int s; 566 567 s = splsoftnet(); 568 pool_put(&tcpcb_pool, tp); 569 splx(s); 570 tcpstat.tcps_closed++; 571 } 572 573 int 574 tcp_freeq(struct tcpcb *tp) 575 { 576 struct tcpqent *qe; 577 int rv = 0; 578 579 while ((qe = TAILQ_FIRST(&tp->t_segq)) != NULL) { 580 TAILQ_REMOVE(&tp->t_segq, qe, tcpqe_q); 581 m_freem(qe->tcpqe_m); 582 pool_put(&tcpqe_pool, qe); 583 rv = 1; 584 } 585 return (rv); 586 } 587 588 /* 589 * Compute proper scaling value for receiver window from buffer space 590 */ 591 592 void 593 tcp_rscale(struct tcpcb *tp, u_long hiwat) 594 { 595 tp->request_r_scale = 0; 596 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 597 TCP_MAXWIN << tp->request_r_scale < hiwat) 598 tp->request_r_scale++; 599 } 600 601 /* 602 * Notify a tcp user of an asynchronous error; 603 * store error as soft error, but wake up user 604 * (for now, won't do anything until can select for soft error). 605 */ 606 void 607 tcp_notify(inp, error) 608 struct inpcb *inp; 609 int error; 610 { 611 struct tcpcb *tp = intotcpcb(inp); 612 struct socket *so = inp->inp_socket; 613 614 /* 615 * Ignore some errors if we are hooked up. 616 * If connection hasn't completed, has retransmitted several times, 617 * and receives a second error, give up now. This is better 618 * than waiting a long time to establish a connection that 619 * can never complete. 620 */ 621 if (tp->t_state == TCPS_ESTABLISHED && 622 (error == EHOSTUNREACH || error == ENETUNREACH || 623 error == EHOSTDOWN)) { 624 return; 625 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 626 tp->t_rxtshift > 3 && tp->t_softerror) 627 so->so_error = error; 628 else 629 tp->t_softerror = error; 630 wakeup((caddr_t) &so->so_timeo); 631 sorwakeup(so); 632 sowwakeup(so); 633 } 634 635 #ifdef INET6 636 void 637 tcp6_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *d) 638 { 639 struct tcphdr th; 640 struct tcpcb *tp; 641 void (*notify)(struct inpcb *, int) = tcp_notify; 642 struct ip6_hdr *ip6; 643 const struct sockaddr_in6 *sa6_src = NULL; 644 struct sockaddr_in6 *sa6 = satosin6(sa); 645 struct inpcb *inp; 646 struct mbuf *m; 647 tcp_seq seq; 648 int off; 649 struct { 650 u_int16_t th_sport; 651 u_int16_t th_dport; 652 u_int32_t th_seq; 653 } *thp; 654 655 if (sa->sa_family != AF_INET6 || 656 sa->sa_len != sizeof(struct sockaddr_in6) || 657 IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) || 658 IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) 659 return; 660 if ((unsigned)cmd >= PRC_NCMDS) 661 return; 662 else if (cmd == PRC_QUENCH) { 663 /* 664 * Don't honor ICMP Source Quench messages meant for 665 * TCP connections. 666 */ 667 /* XXX there's no PRC_QUENCH in IPv6 */ 668 return; 669 } else if (PRC_IS_REDIRECT(cmd)) 670 notify = in_rtchange, d = NULL; 671 else if (cmd == PRC_MSGSIZE) 672 ; /* special code is present, see below */ 673 else if (cmd == PRC_HOSTDEAD) 674 d = NULL; 675 else if (inet6ctlerrmap[cmd] == 0) 676 return; 677 678 /* if the parameter is from icmp6, decode it. */ 679 if (d != NULL) { 680 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 681 m = ip6cp->ip6c_m; 682 ip6 = ip6cp->ip6c_ip6; 683 off = ip6cp->ip6c_off; 684 sa6_src = ip6cp->ip6c_src; 685 } else { 686 m = NULL; 687 ip6 = NULL; 688 sa6_src = &sa6_any; 689 } 690 691 if (ip6) { 692 /* 693 * XXX: We assume that when ip6 is non NULL, 694 * M and OFF are valid. 695 */ 696 697 /* check if we can safely examine src and dst ports */ 698 if (m->m_pkthdr.len < off + sizeof(*thp)) 699 return; 700 701 bzero(&th, sizeof(th)); 702 #ifdef DIAGNOSTIC 703 if (sizeof(*thp) > sizeof(th)) 704 panic("assumption failed in tcp6_ctlinput"); 705 #endif 706 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 707 708 /* 709 * Check to see if we have a valid TCP connection 710 * corresponding to the address in the ICMPv6 message 711 * payload. 712 */ 713 inp = in6_pcbhashlookup(&tcbtable, &sa6->sin6_addr, 714 th.th_dport, (struct in6_addr *)&sa6_src->sin6_addr, 715 th.th_sport, rdomain); 716 if (cmd == PRC_MSGSIZE) { 717 /* 718 * Depending on the value of "valid" and routing table 719 * size (mtudisc_{hi,lo}wat), we will: 720 * - recalcurate the new MTU and create the 721 * corresponding routing entry, or 722 * - ignore the MTU change notification. 723 */ 724 icmp6_mtudisc_update((struct ip6ctlparam *)d, inp != NULL); 725 return; 726 } 727 if (inp) { 728 seq = ntohl(th.th_seq); 729 if (inp->inp_socket && 730 (tp = intotcpcb(inp)) && 731 SEQ_GEQ(seq, tp->snd_una) && 732 SEQ_LT(seq, tp->snd_max)) 733 notify(inp, inet6ctlerrmap[cmd]); 734 } else if (syn_cache_count && 735 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 736 inet6ctlerrmap[cmd] == ENETUNREACH || 737 inet6ctlerrmap[cmd] == EHOSTDOWN)) 738 syn_cache_unreach((struct sockaddr *)sa6_src, 739 sa, &th, rdomain); 740 } else { 741 (void) in6_pcbnotify(&tcbtable, sa6, 0, 742 sa6_src, 0, rdomain, cmd, NULL, notify); 743 } 744 } 745 #endif 746 747 void * 748 tcp_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *v) 749 { 750 struct ip *ip = v; 751 struct tcphdr *th; 752 struct tcpcb *tp; 753 struct inpcb *inp; 754 struct in_addr faddr; 755 tcp_seq seq; 756 u_int mtu; 757 void (*notify)(struct inpcb *, int) = tcp_notify; 758 int errno; 759 760 if (sa->sa_family != AF_INET) 761 return NULL; 762 faddr = satosin(sa)->sin_addr; 763 if (faddr.s_addr == INADDR_ANY) 764 return NULL; 765 766 if ((unsigned)cmd >= PRC_NCMDS) 767 return NULL; 768 errno = inetctlerrmap[cmd]; 769 if (cmd == PRC_QUENCH) 770 /* 771 * Don't honor ICMP Source Quench messages meant for 772 * TCP connections. 773 */ 774 return NULL; 775 else if (PRC_IS_REDIRECT(cmd)) 776 notify = in_rtchange, ip = 0; 777 else if (cmd == PRC_MSGSIZE && ip_mtudisc && ip) { 778 /* 779 * Verify that the packet in the icmp payload refers 780 * to an existing TCP connection. 781 */ 782 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 783 seq = ntohl(th->th_seq); 784 inp = in_pcbhashlookup(&tcbtable, 785 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 786 rdomain); 787 if (inp && (tp = intotcpcb(inp)) && 788 SEQ_GEQ(seq, tp->snd_una) && 789 SEQ_LT(seq, tp->snd_max)) { 790 struct icmp *icp; 791 icp = (struct icmp *)((caddr_t)ip - 792 offsetof(struct icmp, icmp_ip)); 793 794 /* 795 * If the ICMP message advertises a Next-Hop MTU 796 * equal or larger than the maximum packet size we have 797 * ever sent, drop the message. 798 */ 799 mtu = (u_int)ntohs(icp->icmp_nextmtu); 800 if (mtu >= tp->t_pmtud_mtu_sent) 801 return NULL; 802 if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) { 803 /* 804 * Calculate new MTU, and create corresponding 805 * route (traditional PMTUD). 806 */ 807 tp->t_flags &= ~TF_PMTUD_PEND; 808 icmp_mtudisc(icp, inp->inp_rtableid); 809 } else { 810 /* 811 * Record the information got in the ICMP 812 * message; act on it later. 813 * If we had already recorded an ICMP message, 814 * replace the old one only if the new message 815 * refers to an older TCP segment 816 */ 817 if (tp->t_flags & TF_PMTUD_PEND) { 818 if (SEQ_LT(tp->t_pmtud_th_seq, seq)) 819 return NULL; 820 } else 821 tp->t_flags |= TF_PMTUD_PEND; 822 tp->t_pmtud_th_seq = seq; 823 tp->t_pmtud_nextmtu = icp->icmp_nextmtu; 824 tp->t_pmtud_ip_len = icp->icmp_ip.ip_len; 825 tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl; 826 return NULL; 827 } 828 } else { 829 /* ignore if we don't have a matching connection */ 830 return NULL; 831 } 832 notify = tcp_mtudisc, ip = 0; 833 } else if (cmd == PRC_MTUINC) 834 notify = tcp_mtudisc_increase, ip = 0; 835 else if (cmd == PRC_HOSTDEAD) 836 ip = 0; 837 else if (errno == 0) 838 return NULL; 839 840 if (ip) { 841 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 842 inp = in_pcbhashlookup(&tcbtable, 843 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 844 rdomain); 845 if (inp) { 846 seq = ntohl(th->th_seq); 847 if (inp->inp_socket && 848 (tp = intotcpcb(inp)) && 849 SEQ_GEQ(seq, tp->snd_una) && 850 SEQ_LT(seq, tp->snd_max)) 851 notify(inp, errno); 852 } else if (syn_cache_count && 853 (inetctlerrmap[cmd] == EHOSTUNREACH || 854 inetctlerrmap[cmd] == ENETUNREACH || 855 inetctlerrmap[cmd] == EHOSTDOWN)) { 856 struct sockaddr_in sin; 857 858 bzero(&sin, sizeof(sin)); 859 sin.sin_len = sizeof(sin); 860 sin.sin_family = AF_INET; 861 sin.sin_port = th->th_sport; 862 sin.sin_addr = ip->ip_src; 863 syn_cache_unreach((struct sockaddr *)&sin, 864 sa, th, rdomain); 865 } 866 } else 867 in_pcbnotifyall(&tcbtable, sa, rdomain, errno, notify); 868 869 return NULL; 870 } 871 872 873 #ifdef INET6 874 /* 875 * Path MTU Discovery handlers. 876 */ 877 void 878 tcp6_mtudisc_callback(sin6, rdomain) 879 struct sockaddr_in6 *sin6; 880 u_int rdomain; 881 { 882 (void) in6_pcbnotify(&tcbtable, sin6, 0, 883 &sa6_any, 0, rdomain, PRC_MSGSIZE, NULL, tcp_mtudisc); 884 } 885 #endif /* INET6 */ 886 887 /* 888 * On receipt of path MTU corrections, flush old route and replace it 889 * with the new one. Retransmit all unacknowledged packets, to ensure 890 * that all packets will be received. 891 */ 892 void 893 tcp_mtudisc(inp, errno) 894 struct inpcb *inp; 895 int errno; 896 { 897 struct tcpcb *tp = intotcpcb(inp); 898 struct rtentry *rt = in_pcbrtentry(inp); 899 int change = 0; 900 901 if (tp != 0) { 902 int orig_maxseg = tp->t_maxseg; 903 if (rt != 0) { 904 /* 905 * If this was not a host route, remove and realloc. 906 */ 907 if ((rt->rt_flags & RTF_HOST) == 0) { 908 in_rtchange(inp, errno); 909 if ((rt = in_pcbrtentry(inp)) == 0) 910 return; 911 } 912 if (orig_maxseg != tp->t_maxseg || 913 (rt->rt_rmx.rmx_locks & RTV_MTU)) 914 change = 1; 915 } 916 tcp_mss(tp, -1); 917 918 /* 919 * Resend unacknowledged packets 920 */ 921 tp->snd_nxt = tp->snd_una; 922 if (change || errno > 0) 923 tcp_output(tp); 924 } 925 } 926 927 void 928 tcp_mtudisc_increase(inp, errno) 929 struct inpcb *inp; 930 int errno; 931 { 932 struct tcpcb *tp = intotcpcb(inp); 933 struct rtentry *rt = in_pcbrtentry(inp); 934 935 if (tp != 0 && rt != 0) { 936 /* 937 * If this was a host route, remove and realloc. 938 */ 939 if (rt->rt_flags & RTF_HOST) 940 in_rtchange(inp, errno); 941 942 /* also takes care of congestion window */ 943 tcp_mss(tp, -1); 944 } 945 } 946 947 #define TCP_ISS_CONN_INC 4096 948 int tcp_secret_init; 949 u_char tcp_secret[16]; 950 SHA2_CTX tcp_secret_ctx; 951 952 void 953 tcp_set_iss_tsm(struct tcpcb *tp) 954 { 955 SHA2_CTX ctx; 956 union { 957 uint8_t bytes[SHA512_DIGEST_LENGTH]; 958 uint32_t words[2]; 959 } digest; 960 u_int rdomain = rtable_l2(tp->t_inpcb->inp_rtableid); 961 962 if (tcp_secret_init == 0) { 963 arc4random_buf(tcp_secret, sizeof(tcp_secret)); 964 SHA512Init(&tcp_secret_ctx); 965 SHA512Update(&tcp_secret_ctx, tcp_secret, sizeof(tcp_secret)); 966 tcp_secret_init = 1; 967 } 968 ctx = tcp_secret_ctx; 969 SHA512Update(&ctx, &rdomain, sizeof(rdomain)); 970 SHA512Update(&ctx, &tp->t_inpcb->inp_lport, sizeof(u_short)); 971 SHA512Update(&ctx, &tp->t_inpcb->inp_fport, sizeof(u_short)); 972 if (tp->pf == AF_INET6) { 973 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr6, 974 sizeof(struct in6_addr)); 975 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr6, 976 sizeof(struct in6_addr)); 977 } else { 978 SHA512Update(&ctx, &tp->t_inpcb->inp_laddr, 979 sizeof(struct in_addr)); 980 SHA512Update(&ctx, &tp->t_inpcb->inp_faddr, 981 sizeof(struct in_addr)); 982 } 983 SHA512Final(digest.bytes, &ctx); 984 tcp_iss += TCP_ISS_CONN_INC; 985 tp->iss = digest.words[0] + tcp_iss; 986 tp->ts_modulate = digest.words[1]; 987 } 988 989 #ifdef TCP_SIGNATURE 990 int 991 tcp_signature_tdb_attach() 992 { 993 return (0); 994 } 995 996 int 997 tcp_signature_tdb_init(tdbp, xsp, ii) 998 struct tdb *tdbp; 999 struct xformsw *xsp; 1000 struct ipsecinit *ii; 1001 { 1002 if ((ii->ii_authkeylen < 1) || (ii->ii_authkeylen > 80)) 1003 return (EINVAL); 1004 1005 tdbp->tdb_amxkey = malloc(ii->ii_authkeylen, M_XDATA, M_NOWAIT); 1006 if (tdbp->tdb_amxkey == NULL) 1007 return (ENOMEM); 1008 bcopy(ii->ii_authkey, tdbp->tdb_amxkey, ii->ii_authkeylen); 1009 tdbp->tdb_amxkeylen = ii->ii_authkeylen; 1010 1011 return (0); 1012 } 1013 1014 int 1015 tcp_signature_tdb_zeroize(tdbp) 1016 struct tdb *tdbp; 1017 { 1018 if (tdbp->tdb_amxkey) { 1019 explicit_bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); 1020 free(tdbp->tdb_amxkey, M_XDATA, 0); 1021 tdbp->tdb_amxkey = NULL; 1022 } 1023 1024 return (0); 1025 } 1026 1027 int 1028 tcp_signature_tdb_input(m, tdbp, skip, protoff) 1029 struct mbuf *m; 1030 struct tdb *tdbp; 1031 int skip, protoff; 1032 { 1033 return (0); 1034 } 1035 1036 int 1037 tcp_signature_tdb_output(m, tdbp, mp, skip, protoff) 1038 struct mbuf *m; 1039 struct tdb *tdbp; 1040 struct mbuf **mp; 1041 int skip, protoff; 1042 { 1043 return (EINVAL); 1044 } 1045 1046 int 1047 tcp_signature_apply(fstate, data, len) 1048 caddr_t fstate; 1049 caddr_t data; 1050 unsigned int len; 1051 { 1052 MD5Update((MD5_CTX *)fstate, (char *)data, len); 1053 return 0; 1054 } 1055 1056 int 1057 tcp_signature(struct tdb *tdb, int af, struct mbuf *m, struct tcphdr *th, 1058 int iphlen, int doswap, char *sig) 1059 { 1060 MD5_CTX ctx; 1061 int len; 1062 struct tcphdr th0; 1063 1064 MD5Init(&ctx); 1065 1066 switch(af) { 1067 case 0: 1068 case AF_INET: { 1069 struct ippseudo ippseudo; 1070 struct ip *ip; 1071 1072 ip = mtod(m, struct ip *); 1073 1074 ippseudo.ippseudo_src = ip->ip_src; 1075 ippseudo.ippseudo_dst = ip->ip_dst; 1076 ippseudo.ippseudo_pad = 0; 1077 ippseudo.ippseudo_p = IPPROTO_TCP; 1078 ippseudo.ippseudo_len = htons(m->m_pkthdr.len - iphlen); 1079 1080 MD5Update(&ctx, (char *)&ippseudo, 1081 sizeof(struct ippseudo)); 1082 break; 1083 } 1084 #ifdef INET6 1085 case AF_INET6: { 1086 struct ip6_hdr_pseudo ip6pseudo; 1087 struct ip6_hdr *ip6; 1088 1089 ip6 = mtod(m, struct ip6_hdr *); 1090 bzero(&ip6pseudo, sizeof(ip6pseudo)); 1091 ip6pseudo.ip6ph_src = ip6->ip6_src; 1092 ip6pseudo.ip6ph_dst = ip6->ip6_dst; 1093 in6_clearscope(&ip6pseudo.ip6ph_src); 1094 in6_clearscope(&ip6pseudo.ip6ph_dst); 1095 ip6pseudo.ip6ph_nxt = IPPROTO_TCP; 1096 ip6pseudo.ip6ph_len = htonl(m->m_pkthdr.len - iphlen); 1097 1098 MD5Update(&ctx, (char *)&ip6pseudo, 1099 sizeof(ip6pseudo)); 1100 break; 1101 } 1102 #endif 1103 } 1104 1105 th0 = *th; 1106 th0.th_sum = 0; 1107 1108 if (doswap) { 1109 HTONL(th0.th_seq); 1110 HTONL(th0.th_ack); 1111 HTONS(th0.th_win); 1112 HTONS(th0.th_urp); 1113 } 1114 MD5Update(&ctx, (char *)&th0, sizeof(th0)); 1115 1116 len = m->m_pkthdr.len - iphlen - th->th_off * sizeof(uint32_t); 1117 1118 if (len > 0 && 1119 m_apply(m, iphlen + th->th_off * sizeof(uint32_t), len, 1120 tcp_signature_apply, (caddr_t)&ctx)) 1121 return (-1); 1122 1123 MD5Update(&ctx, tdb->tdb_amxkey, tdb->tdb_amxkeylen); 1124 MD5Final(sig, &ctx); 1125 1126 return (0); 1127 } 1128 #endif /* TCP_SIGNATURE */ 1129