1 /* $OpenBSD: tcp_subr.c,v 1.114 2012/12/28 17:52:06 gsoares 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/proc.h> 74 #include <sys/mbuf.h> 75 #include <sys/socket.h> 76 #include <sys/socketvar.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/in_systm.h> 86 #include <netinet/ip.h> 87 #include <netinet/in_pcb.h> 88 #include <netinet/ip_var.h> 89 #include <netinet/ip_icmp.h> 90 #include <netinet/tcp.h> 91 #include <netinet/tcp_fsm.h> 92 #include <netinet/tcp_seq.h> 93 #include <netinet/tcp_timer.h> 94 #include <netinet/tcp_var.h> 95 #include <netinet/tcpip.h> 96 #include <dev/rndvar.h> 97 98 #ifdef INET6 99 #include <netinet6/in6_var.h> 100 #include <netinet6/ip6protosw.h> 101 #endif /* INET6 */ 102 103 #include <crypto/md5.h> 104 105 /* patchable/settable parameters for tcp */ 106 int tcp_mssdflt = TCP_MSS; 107 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 108 109 /* values controllable via sysctl */ 110 int tcp_do_rfc1323 = 1; 111 #ifdef TCP_SACK 112 int tcp_do_sack = 1; /* RFC 2018 selective ACKs */ 113 #endif 114 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ 115 #ifdef TCP_ECN 116 int tcp_do_ecn = 0; /* RFC3168 ECN enabled/disabled? */ 117 #endif 118 int tcp_do_rfc3390 = 2; /* Increase TCP's Initial Window to 10*mss */ 119 120 u_int32_t tcp_now = 1; 121 122 #ifndef TCBHASHSIZE 123 #define TCBHASHSIZE 128 124 #endif 125 int tcbhashsize = TCBHASHSIZE; 126 127 /* syn hash parameters */ 128 #define TCP_SYN_HASH_SIZE 293 129 #define TCP_SYN_BUCKET_SIZE 35 130 int tcp_syn_cache_size = TCP_SYN_HASH_SIZE; 131 int tcp_syn_cache_limit = TCP_SYN_HASH_SIZE*TCP_SYN_BUCKET_SIZE; 132 int tcp_syn_bucket_limit = 3*TCP_SYN_BUCKET_SIZE; 133 struct syn_cache_head tcp_syn_cache[TCP_SYN_HASH_SIZE]; 134 135 int tcp_reass_limit = NMBCLUSTERS / 2; /* hardlimit for tcpqe_pool */ 136 #ifdef TCP_SACK 137 int tcp_sackhole_limit = 32*1024; /* hardlimit for sackhl_pool */ 138 #endif 139 140 #ifdef INET6 141 extern int ip6_defhlim; 142 #endif /* INET6 */ 143 144 struct pool tcpcb_pool; 145 struct pool tcpqe_pool; 146 #ifdef TCP_SACK 147 struct pool sackhl_pool; 148 #endif 149 150 struct tcpstat tcpstat; /* tcp statistics */ 151 tcp_seq tcp_iss; 152 153 /* 154 * Tcp initialization 155 */ 156 void 157 tcp_init() 158 { 159 tcp_iss = 1; /* wrong */ 160 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl", 161 NULL); 162 pool_init(&tcpqe_pool, sizeof(struct tcpqent), 0, 0, 0, "tcpqepl", 163 NULL); 164 pool_sethardlimit(&tcpqe_pool, tcp_reass_limit, NULL, 0); 165 #ifdef TCP_SACK 166 pool_init(&sackhl_pool, sizeof(struct sackhole), 0, 0, 0, "sackhlpl", 167 NULL); 168 pool_sethardlimit(&sackhl_pool, tcp_sackhole_limit, NULL, 0); 169 #endif /* TCP_SACK */ 170 in_pcbinit(&tcbtable, tcbhashsize); 171 172 #ifdef INET6 173 /* 174 * Since sizeof(struct ip6_hdr) > sizeof(struct ip), we 175 * do max length checks/computations only on the former. 176 */ 177 if (max_protohdr < (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))) 178 max_protohdr = (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)); 179 if ((max_linkhdr + sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) > 180 MHLEN) 181 panic("tcp_init"); 182 183 icmp6_mtudisc_callback_register(tcp6_mtudisc_callback); 184 #endif /* INET6 */ 185 186 /* Initialize the compressed state engine. */ 187 syn_cache_init(); 188 189 /* Initialize timer state. */ 190 tcp_timer_init(); 191 } 192 193 /* 194 * Create template to be used to send tcp packets on a connection. 195 * Call after host entry created, allocates an mbuf and fills 196 * in a skeletal tcp/ip header, minimizing the amount of work 197 * necessary when the connection is used. 198 * 199 * To support IPv6 in addition to IPv4 and considering that the sizes of 200 * the IPv4 and IPv6 headers are not the same, we now use a separate pointer 201 * for the TCP header. Also, we made the former tcpiphdr header pointer 202 * into just an IP overlay pointer, with casting as appropriate for v6. rja 203 */ 204 struct mbuf * 205 tcp_template(tp) 206 struct tcpcb *tp; 207 { 208 struct inpcb *inp = tp->t_inpcb; 209 struct mbuf *m; 210 struct tcphdr *th; 211 212 if ((m = tp->t_template) == 0) { 213 m = m_get(M_DONTWAIT, MT_HEADER); 214 if (m == NULL) 215 return (0); 216 217 switch (tp->pf) { 218 case 0: /*default to PF_INET*/ 219 #ifdef INET 220 case AF_INET: 221 m->m_len = sizeof(struct ip); 222 break; 223 #endif /* INET */ 224 #ifdef INET6 225 case AF_INET6: 226 m->m_len = sizeof(struct ip6_hdr); 227 break; 228 #endif /* INET6 */ 229 } 230 m->m_len += sizeof (struct tcphdr); 231 232 /* 233 * The link header, network header, TCP header, and TCP options 234 * all must fit in this mbuf. For now, assume the worst case of 235 * TCP options size. Eventually, compute this from tp flags. 236 */ 237 if (m->m_len + MAX_TCPOPTLEN + max_linkhdr >= MHLEN) { 238 MCLGET(m, M_DONTWAIT); 239 if ((m->m_flags & M_EXT) == 0) { 240 m_free(m); 241 return (0); 242 } 243 } 244 } 245 246 switch(tp->pf) { 247 #ifdef INET 248 case AF_INET: 249 { 250 struct ipovly *ipovly; 251 252 ipovly = mtod(m, struct ipovly *); 253 254 bzero(ipovly->ih_x1, sizeof ipovly->ih_x1); 255 ipovly->ih_pr = IPPROTO_TCP; 256 ipovly->ih_len = htons(sizeof (struct tcphdr)); 257 ipovly->ih_src = inp->inp_laddr; 258 ipovly->ih_dst = inp->inp_faddr; 259 260 th = (struct tcphdr *)(mtod(m, caddr_t) + 261 sizeof(struct ip)); 262 th->th_sum = in_cksum_phdr(ipovly->ih_src.s_addr, 263 ipovly->ih_dst.s_addr, 264 htons(sizeof (struct tcphdr) + IPPROTO_TCP)); 265 } 266 break; 267 #endif /* INET */ 268 #ifdef INET6 269 case AF_INET6: 270 { 271 struct ip6_hdr *ip6; 272 273 ip6 = mtod(m, struct ip6_hdr *); 274 275 ip6->ip6_src = inp->inp_laddr6; 276 ip6->ip6_dst = inp->inp_faddr6; 277 ip6->ip6_flow = htonl(0x60000000) | 278 (inp->inp_flowinfo & IPV6_FLOWLABEL_MASK); 279 280 ip6->ip6_nxt = IPPROTO_TCP; 281 ip6->ip6_plen = htons(sizeof(struct tcphdr)); /*XXX*/ 282 ip6->ip6_hlim = in6_selecthlim(inp, NULL); /*XXX*/ 283 284 th = (struct tcphdr *)(mtod(m, caddr_t) + 285 sizeof(struct ip6_hdr)); 286 th->th_sum = 0; 287 } 288 break; 289 #endif /* INET6 */ 290 } 291 292 th->th_sport = inp->inp_lport; 293 th->th_dport = inp->inp_fport; 294 th->th_seq = 0; 295 th->th_ack = 0; 296 th->th_x2 = 0; 297 th->th_off = 5; 298 th->th_flags = 0; 299 th->th_win = 0; 300 th->th_urp = 0; 301 return (m); 302 } 303 304 /* 305 * Send a single message to the TCP at address specified by 306 * the given TCP/IP header. If m == 0, then we make a copy 307 * of the tcpiphdr at ti and send directly to the addressed host. 308 * This is used to force keep alive messages out using the TCP 309 * template for a connection tp->t_template. If flags are given 310 * then we send a message back to the TCP which originated the 311 * segment ti, and discard the mbuf containing it and any other 312 * attached mbufs. 313 * 314 * In any case the ack and sequence number of the transmitted 315 * segment are as specified by the parameters. 316 */ 317 #ifdef INET6 318 /* This function looks hairy, because it was so IPv4-dependent. */ 319 #endif /* INET6 */ 320 void 321 tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0, 322 tcp_seq ack, tcp_seq seq, int flags, u_int rtableid) 323 { 324 int tlen; 325 int win = 0; 326 struct mbuf *m = 0; 327 struct route *ro = 0; 328 struct tcphdr *th; 329 struct ip *ip; 330 struct ipovly *ih; 331 #ifdef INET6 332 struct ip6_hdr *ip6; 333 #endif 334 int af; /* af on wire */ 335 336 if (tp) { 337 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 338 /* 339 * If this is called with an unconnected 340 * socket/tp/pcb (tp->pf is 0), we lose. 341 */ 342 af = tp->pf; 343 344 /* 345 * The route/route6 distinction is meaningless 346 * unless you're allocating space or passing parameters. 347 */ 348 ro = &tp->t_inpcb->inp_route; 349 } else 350 af = (((struct ip *)template)->ip_v == 6) ? AF_INET6 : AF_INET; 351 352 m = m_gethdr(M_DONTWAIT, MT_HEADER); 353 if (m == NULL) 354 return; 355 m->m_data += max_linkhdr; 356 tlen = 0; 357 358 #define xchg(a,b,type) do { type t; t=a; a=b; b=t; } while (0) 359 switch (af) { 360 #ifdef INET6 361 case AF_INET6: 362 ip6 = mtod(m, struct ip6_hdr *); 363 th = (struct tcphdr *)(ip6 + 1); 364 tlen = sizeof(*ip6) + sizeof(*th); 365 if (th0) { 366 bcopy(template, ip6, sizeof(*ip6)); 367 bcopy(th0, th, sizeof(*th)); 368 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 369 } else { 370 bcopy(template, ip6, tlen); 371 } 372 break; 373 #endif /* INET6 */ 374 case AF_INET: 375 ip = mtod(m, struct ip *); 376 th = (struct tcphdr *)(ip + 1); 377 tlen = sizeof(*ip) + sizeof(*th); 378 if (th0) { 379 bcopy(template, ip, sizeof(*ip)); 380 bcopy(th0, th, sizeof(*th)); 381 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, u_int32_t); 382 } else { 383 bcopy(template, ip, tlen); 384 } 385 break; 386 } 387 if (th0) 388 xchg(th->th_dport, th->th_sport, u_int16_t); 389 else 390 flags = TH_ACK; 391 #undef xchg 392 393 m->m_len = tlen; 394 m->m_pkthdr.len = tlen; 395 m->m_pkthdr.rcvif = (struct ifnet *) 0; 396 th->th_seq = htonl(seq); 397 th->th_ack = htonl(ack); 398 th->th_x2 = 0; 399 th->th_off = sizeof (struct tcphdr) >> 2; 400 th->th_flags = flags; 401 if (tp) 402 win >>= tp->rcv_scale; 403 if (win > TCP_MAXWIN) 404 win = TCP_MAXWIN; 405 th->th_win = htons((u_int16_t)win); 406 th->th_urp = 0; 407 408 /* force routing domain */ 409 if (tp) 410 m->m_pkthdr.rdomain = tp->t_inpcb->inp_rtableid; 411 else 412 m->m_pkthdr.rdomain = rtableid; 413 414 switch (af) { 415 #ifdef INET6 416 case AF_INET6: 417 ip6->ip6_flow = htonl(0x60000000); 418 ip6->ip6_nxt = IPPROTO_TCP; 419 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, NULL); /*XXX*/ 420 ip6->ip6_plen = tlen - sizeof(struct ip6_hdr); 421 th->th_sum = 0; 422 th->th_sum = in6_cksum(m, IPPROTO_TCP, 423 sizeof(struct ip6_hdr), ip6->ip6_plen); 424 HTONS(ip6->ip6_plen); 425 ip6_output(m, tp ? tp->t_inpcb->inp_outputopts6 : NULL, 426 (struct route_in6 *)ro, 0, NULL, NULL, 427 tp ? tp->t_inpcb : NULL); 428 break; 429 #endif /* INET6 */ 430 case AF_INET: 431 ih = (struct ipovly *)ip; 432 bzero(ih->ih_x1, sizeof ih->ih_x1); 433 ih->ih_len = htons((u_short)tlen - sizeof(struct ip)); 434 435 /* 436 * There's no point deferring to hardware checksum processing 437 * here, as we only send a minimal TCP packet whose checksum 438 * we need to compute in any case. 439 */ 440 th->th_sum = 0; 441 th->th_sum = in_cksum(m, tlen); 442 ip->ip_len = htons(tlen); 443 ip->ip_ttl = ip_defttl; 444 ip_output(m, (void *)NULL, ro, ip_mtudisc ? IP_MTUDISC : 0, 445 (void *)NULL, tp ? tp->t_inpcb : (void *)NULL); 446 } 447 } 448 449 /* 450 * Create a new TCP control block, making an 451 * empty reassembly queue and hooking it to the argument 452 * protocol control block. 453 */ 454 struct tcpcb * 455 tcp_newtcpcb(struct inpcb *inp) 456 { 457 struct tcpcb *tp; 458 int i; 459 460 tp = pool_get(&tcpcb_pool, PR_NOWAIT|PR_ZERO); 461 if (tp == NULL) 462 return ((struct tcpcb *)0); 463 TAILQ_INIT(&tp->t_segq); 464 tp->t_maxseg = tcp_mssdflt; 465 tp->t_maxopd = 0; 466 467 TCP_INIT_DELACK(tp); 468 for (i = 0; i < TCPT_NTIMERS; i++) 469 TCP_TIMER_INIT(tp, i); 470 timeout_set(&tp->t_reap_to, tcp_reaper, tp); 471 472 #ifdef TCP_SACK 473 tp->sack_enable = tcp_do_sack; 474 #endif 475 tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; 476 tp->t_inpcb = inp; 477 /* 478 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 479 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 480 * reasonable initial retransmit time. 481 */ 482 tp->t_srtt = TCPTV_SRTTBASE; 483 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << 484 (TCP_RTTVAR_SHIFT + TCP_RTT_BASE_SHIFT - 1); 485 tp->t_rttmin = TCPTV_MIN; 486 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 487 TCPTV_MIN, TCPTV_REXMTMAX); 488 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 489 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 490 491 tp->t_pmtud_mtu_sent = 0; 492 tp->t_pmtud_mss_acked = 0; 493 494 #ifdef INET6 495 /* we disallow IPv4 mapped address completely. */ 496 if ((inp->inp_flags & INP_IPV6) == 0) 497 tp->pf = PF_INET; 498 else 499 tp->pf = PF_INET6; 500 #else 501 tp->pf = PF_INET; 502 #endif 503 504 #ifdef INET6 505 if (inp->inp_flags & INP_IPV6) 506 inp->inp_ipv6.ip6_hlim = ip6_defhlim; 507 else 508 #endif /* INET6 */ 509 inp->inp_ip.ip_ttl = ip_defttl; 510 511 inp->inp_ppcb = (caddr_t)tp; 512 return (tp); 513 } 514 515 /* 516 * Drop a TCP connection, reporting 517 * the specified error. If connection is synchronized, 518 * then send a RST to peer. 519 */ 520 struct tcpcb * 521 tcp_drop(tp, errno) 522 struct tcpcb *tp; 523 int errno; 524 { 525 struct socket *so = tp->t_inpcb->inp_socket; 526 527 if (TCPS_HAVERCVDSYN(tp->t_state)) { 528 tp->t_state = TCPS_CLOSED; 529 (void) tcp_output(tp); 530 tcpstat.tcps_drops++; 531 } else 532 tcpstat.tcps_conndrops++; 533 if (errno == ETIMEDOUT && tp->t_softerror) 534 errno = tp->t_softerror; 535 so->so_error = errno; 536 return (tcp_close(tp)); 537 } 538 539 /* 540 * Close a TCP control block: 541 * discard all space held by the tcp 542 * discard internet protocol block 543 * wake up any sleepers 544 */ 545 struct tcpcb * 546 tcp_close(struct tcpcb *tp) 547 { 548 struct inpcb *inp = tp->t_inpcb; 549 struct socket *so = inp->inp_socket; 550 #ifdef TCP_SACK 551 struct sackhole *p, *q; 552 #endif 553 554 /* free the reassembly queue, if any */ 555 tcp_freeq(tp); 556 557 tcp_canceltimers(tp); 558 TCP_CLEAR_DELACK(tp); 559 syn_cache_cleanup(tp); 560 561 #ifdef TCP_SACK 562 /* Free SACK holes. */ 563 q = p = tp->snd_holes; 564 while (p != 0) { 565 q = p->next; 566 pool_put(&sackhl_pool, p); 567 p = q; 568 } 569 #endif 570 if (tp->t_template) 571 (void) m_free(tp->t_template); 572 573 tp->t_flags |= TF_DEAD; 574 timeout_add(&tp->t_reap_to, 0); 575 576 inp->inp_ppcb = 0; 577 soisdisconnected(so); 578 in_pcbdetach(inp); 579 return ((struct tcpcb *)0); 580 } 581 582 void 583 tcp_reaper(void *arg) 584 { 585 struct tcpcb *tp = arg; 586 int s; 587 588 s = splsoftnet(); 589 pool_put(&tcpcb_pool, tp); 590 splx(s); 591 tcpstat.tcps_closed++; 592 } 593 594 int 595 tcp_freeq(struct tcpcb *tp) 596 { 597 struct tcpqent *qe; 598 int rv = 0; 599 600 while ((qe = TAILQ_FIRST(&tp->t_segq)) != NULL) { 601 TAILQ_REMOVE(&tp->t_segq, qe, tcpqe_q); 602 m_freem(qe->tcpqe_m); 603 pool_put(&tcpqe_pool, qe); 604 rv = 1; 605 } 606 return (rv); 607 } 608 609 /* 610 * Compute proper scaling value for receiver window from buffer space 611 */ 612 613 void 614 tcp_rscale(struct tcpcb *tp, u_long hiwat) 615 { 616 tp->request_r_scale = 0; 617 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 618 TCP_MAXWIN << tp->request_r_scale < hiwat) 619 tp->request_r_scale++; 620 } 621 622 /* 623 * Notify a tcp user of an asynchronous error; 624 * store error as soft error, but wake up user 625 * (for now, won't do anything until can select for soft error). 626 */ 627 void 628 tcp_notify(inp, error) 629 struct inpcb *inp; 630 int error; 631 { 632 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 633 struct socket *so = inp->inp_socket; 634 635 /* 636 * Ignore some errors if we are hooked up. 637 * If connection hasn't completed, has retransmitted several times, 638 * and receives a second error, give up now. This is better 639 * than waiting a long time to establish a connection that 640 * can never complete. 641 */ 642 if (tp->t_state == TCPS_ESTABLISHED && 643 (error == EHOSTUNREACH || error == ENETUNREACH || 644 error == EHOSTDOWN)) { 645 return; 646 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 647 tp->t_rxtshift > 3 && tp->t_softerror) 648 so->so_error = error; 649 else 650 tp->t_softerror = error; 651 wakeup((caddr_t) &so->so_timeo); 652 sorwakeup(so); 653 sowwakeup(so); 654 } 655 656 #ifdef INET6 657 void 658 tcp6_ctlinput(cmd, sa, d) 659 int cmd; 660 struct sockaddr *sa; 661 void *d; 662 { 663 struct tcphdr th; 664 struct tcpcb *tp; 665 void (*notify)(struct inpcb *, int) = tcp_notify; 666 struct ip6_hdr *ip6; 667 const struct sockaddr_in6 *sa6_src = NULL; 668 struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)sa; 669 struct inpcb *inp; 670 struct mbuf *m; 671 tcp_seq seq; 672 int off; 673 struct { 674 u_int16_t th_sport; 675 u_int16_t th_dport; 676 u_int32_t th_seq; 677 } *thp; 678 679 if (sa->sa_family != AF_INET6 || 680 sa->sa_len != sizeof(struct sockaddr_in6) || 681 IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) || 682 IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) 683 return; 684 if ((unsigned)cmd >= PRC_NCMDS) 685 return; 686 else if (cmd == PRC_QUENCH) { 687 /* 688 * Don't honor ICMP Source Quench messages meant for 689 * TCP connections. 690 */ 691 /* XXX there's no PRC_QUENCH in IPv6 */ 692 return; 693 } else if (PRC_IS_REDIRECT(cmd)) 694 notify = in_rtchange, d = NULL; 695 else if (cmd == PRC_MSGSIZE) 696 ; /* special code is present, see below */ 697 else if (cmd == PRC_HOSTDEAD) 698 d = NULL; 699 else if (inet6ctlerrmap[cmd] == 0) 700 return; 701 702 /* if the parameter is from icmp6, decode it. */ 703 if (d != NULL) { 704 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 705 m = ip6cp->ip6c_m; 706 ip6 = ip6cp->ip6c_ip6; 707 off = ip6cp->ip6c_off; 708 sa6_src = ip6cp->ip6c_src; 709 } else { 710 m = NULL; 711 ip6 = NULL; 712 sa6_src = &sa6_any; 713 } 714 715 if (ip6) { 716 /* 717 * XXX: We assume that when ip6 is non NULL, 718 * M and OFF are valid. 719 */ 720 721 /* check if we can safely examine src and dst ports */ 722 if (m->m_pkthdr.len < off + sizeof(*thp)) 723 return; 724 725 bzero(&th, sizeof(th)); 726 #ifdef DIAGNOSTIC 727 if (sizeof(*thp) > sizeof(th)) 728 panic("assumption failed in tcp6_ctlinput"); 729 #endif 730 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 731 732 /* 733 * Check to see if we have a valid TCP connection 734 * corresponding to the address in the ICMPv6 message 735 * payload. 736 */ 737 inp = in6_pcbhashlookup(&tcbtable, &sa6->sin6_addr, 738 th.th_dport, (struct in6_addr *)&sa6_src->sin6_addr, 739 th.th_sport); 740 if (cmd == PRC_MSGSIZE) { 741 /* 742 * Depending on the value of "valid" and routing table 743 * size (mtudisc_{hi,lo}wat), we will: 744 * - recalcurate the new MTU and create the 745 * corresponding routing entry, or 746 * - ignore the MTU change notification. 747 */ 748 icmp6_mtudisc_update((struct ip6ctlparam *)d, inp != NULL); 749 return; 750 } 751 if (inp) { 752 seq = ntohl(th.th_seq); 753 if (inp->inp_socket && 754 (tp = intotcpcb(inp)) && 755 SEQ_GEQ(seq, tp->snd_una) && 756 SEQ_LT(seq, tp->snd_max)) 757 notify(inp, inet6ctlerrmap[cmd]); 758 } else if (syn_cache_count && 759 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 760 inet6ctlerrmap[cmd] == ENETUNREACH || 761 inet6ctlerrmap[cmd] == EHOSTDOWN)) 762 syn_cache_unreach((struct sockaddr *)sa6_src, 763 sa, &th, /* XXX */ 0); 764 } else { 765 (void) in6_pcbnotify(&tcbtable, sa, 0, 766 (struct sockaddr *)sa6_src, 0, cmd, NULL, notify); 767 } 768 } 769 #endif 770 771 void * 772 tcp_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *v) 773 { 774 struct ip *ip = v; 775 struct tcphdr *th; 776 struct tcpcb *tp; 777 struct inpcb *inp; 778 struct in_addr faddr; 779 tcp_seq seq; 780 u_int mtu; 781 extern int inetctlerrmap[]; 782 void (*notify)(struct inpcb *, int) = tcp_notify; 783 int errno; 784 785 if (sa->sa_family != AF_INET) 786 return NULL; 787 faddr = satosin(sa)->sin_addr; 788 if (faddr.s_addr == INADDR_ANY) 789 return NULL; 790 791 if ((unsigned)cmd >= PRC_NCMDS) 792 return NULL; 793 errno = inetctlerrmap[cmd]; 794 if (cmd == PRC_QUENCH) 795 /* 796 * Don't honor ICMP Source Quench messages meant for 797 * TCP connections. 798 */ 799 return NULL; 800 else if (PRC_IS_REDIRECT(cmd)) 801 notify = in_rtchange, ip = 0; 802 else if (cmd == PRC_MSGSIZE && ip_mtudisc && ip) { 803 /* 804 * Verify that the packet in the icmp payload refers 805 * to an existing TCP connection. 806 */ 807 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 808 seq = ntohl(th->th_seq); 809 inp = in_pcbhashlookup(&tcbtable, 810 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 811 rdomain); 812 if (inp && (tp = intotcpcb(inp)) && 813 SEQ_GEQ(seq, tp->snd_una) && 814 SEQ_LT(seq, tp->snd_max)) { 815 struct icmp *icp; 816 icp = (struct icmp *)((caddr_t)ip - 817 offsetof(struct icmp, icmp_ip)); 818 819 /* 820 * If the ICMP message advertises a Next-Hop MTU 821 * equal or larger than the maximum packet size we have 822 * ever sent, drop the message. 823 */ 824 mtu = (u_int)ntohs(icp->icmp_nextmtu); 825 if (mtu >= tp->t_pmtud_mtu_sent) 826 return NULL; 827 if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) { 828 /* 829 * Calculate new MTU, and create corresponding 830 * route (traditional PMTUD). 831 */ 832 tp->t_flags &= ~TF_PMTUD_PEND; 833 icmp_mtudisc(icp, inp->inp_rtableid); 834 } else { 835 /* 836 * Record the information got in the ICMP 837 * message; act on it later. 838 * If we had already recorded an ICMP message, 839 * replace the old one only if the new message 840 * refers to an older TCP segment 841 */ 842 if (tp->t_flags & TF_PMTUD_PEND) { 843 if (SEQ_LT(tp->t_pmtud_th_seq, seq)) 844 return NULL; 845 } else 846 tp->t_flags |= TF_PMTUD_PEND; 847 tp->t_pmtud_th_seq = seq; 848 tp->t_pmtud_nextmtu = icp->icmp_nextmtu; 849 tp->t_pmtud_ip_len = icp->icmp_ip.ip_len; 850 tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl; 851 return NULL; 852 } 853 } else { 854 /* ignore if we don't have a matching connection */ 855 return NULL; 856 } 857 notify = tcp_mtudisc, ip = 0; 858 } else if (cmd == PRC_MTUINC) 859 notify = tcp_mtudisc_increase, ip = 0; 860 else if (cmd == PRC_HOSTDEAD) 861 ip = 0; 862 else if (errno == 0) 863 return NULL; 864 865 if (ip) { 866 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 867 inp = in_pcbhashlookup(&tcbtable, 868 ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport, 869 rdomain); 870 if (inp) { 871 seq = ntohl(th->th_seq); 872 if (inp->inp_socket && 873 (tp = intotcpcb(inp)) && 874 SEQ_GEQ(seq, tp->snd_una) && 875 SEQ_LT(seq, tp->snd_max)) 876 notify(inp, errno); 877 } else if (syn_cache_count && 878 (inetctlerrmap[cmd] == EHOSTUNREACH || 879 inetctlerrmap[cmd] == ENETUNREACH || 880 inetctlerrmap[cmd] == EHOSTDOWN)) { 881 struct sockaddr_in sin; 882 883 bzero(&sin, sizeof(sin)); 884 sin.sin_len = sizeof(sin); 885 sin.sin_family = AF_INET; 886 sin.sin_port = th->th_sport; 887 sin.sin_addr = ip->ip_src; 888 syn_cache_unreach((struct sockaddr *)&sin, 889 sa, th, rdomain); 890 } 891 } else 892 in_pcbnotifyall(&tcbtable, sa, rdomain, errno, notify); 893 894 return NULL; 895 } 896 897 898 #ifdef INET6 899 /* 900 * Path MTU Discovery handlers. 901 */ 902 void 903 tcp6_mtudisc_callback(faddr) 904 struct in6_addr *faddr; 905 { 906 struct sockaddr_in6 sin6; 907 908 bzero(&sin6, sizeof(sin6)); 909 sin6.sin6_family = AF_INET6; 910 sin6.sin6_len = sizeof(struct sockaddr_in6); 911 sin6.sin6_addr = *faddr; 912 (void) in6_pcbnotify(&tcbtable, (struct sockaddr *)&sin6, 0, 913 (struct sockaddr *)&sa6_any, 0, PRC_MSGSIZE, NULL, tcp_mtudisc); 914 } 915 #endif /* INET6 */ 916 917 /* 918 * On receipt of path MTU corrections, flush old route and replace it 919 * with the new one. Retransmit all unacknowledged packets, to ensure 920 * that all packets will be received. 921 */ 922 void 923 tcp_mtudisc(inp, errno) 924 struct inpcb *inp; 925 int errno; 926 { 927 struct tcpcb *tp = intotcpcb(inp); 928 struct rtentry *rt = in_pcbrtentry(inp); 929 int change = 0; 930 931 if (tp != 0) { 932 int orig_maxseg = tp->t_maxseg; 933 if (rt != 0) { 934 /* 935 * If this was not a host route, remove and realloc. 936 */ 937 if ((rt->rt_flags & RTF_HOST) == 0) { 938 in_rtchange(inp, errno); 939 if ((rt = in_pcbrtentry(inp)) == 0) 940 return; 941 } 942 if (orig_maxseg != tp->t_maxseg || 943 (rt->rt_rmx.rmx_locks & RTV_MTU)) 944 change = 1; 945 } 946 tcp_mss(tp, -1); 947 948 /* 949 * Resend unacknowledged packets 950 */ 951 tp->snd_nxt = tp->snd_una; 952 if (change || errno > 0) 953 tcp_output(tp); 954 } 955 } 956 957 void 958 tcp_mtudisc_increase(inp, errno) 959 struct inpcb *inp; 960 int errno; 961 { 962 struct tcpcb *tp = intotcpcb(inp); 963 struct rtentry *rt = in_pcbrtentry(inp); 964 965 if (tp != 0 && rt != 0) { 966 /* 967 * If this was a host route, remove and realloc. 968 */ 969 if (rt->rt_flags & RTF_HOST) 970 in_rtchange(inp, errno); 971 972 /* also takes care of congestion window */ 973 tcp_mss(tp, -1); 974 } 975 } 976 977 #define TCP_ISS_CONN_INC 4096 978 int tcp_secret_init; 979 u_char tcp_secret[16]; 980 MD5_CTX tcp_secret_ctx; 981 982 void 983 tcp_set_iss_tsm(struct tcpcb *tp) 984 { 985 MD5_CTX ctx; 986 u_int32_t digest[4]; 987 988 if (tcp_secret_init == 0) { 989 arc4random_buf(tcp_secret, sizeof(tcp_secret)); 990 MD5Init(&tcp_secret_ctx); 991 MD5Update(&tcp_secret_ctx, tcp_secret, sizeof(tcp_secret)); 992 tcp_secret_init = 1; 993 } 994 ctx = tcp_secret_ctx; 995 MD5Update(&ctx, (char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 996 MD5Update(&ctx, (char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 997 if (tp->pf == AF_INET6) { 998 MD5Update(&ctx, (char *)&tp->t_inpcb->inp_laddr6, 999 sizeof(struct in6_addr)); 1000 MD5Update(&ctx, (char *)&tp->t_inpcb->inp_faddr6, 1001 sizeof(struct in6_addr)); 1002 } else { 1003 MD5Update(&ctx, (char *)&tp->t_inpcb->inp_laddr, 1004 sizeof(struct in_addr)); 1005 MD5Update(&ctx, (char *)&tp->t_inpcb->inp_faddr, 1006 sizeof(struct in_addr)); 1007 } 1008 MD5Final((u_char *)digest, &ctx); 1009 tcp_iss += TCP_ISS_CONN_INC; 1010 tp->iss = digest[0] + tcp_iss; 1011 tp->ts_modulate = digest[1]; 1012 } 1013 1014 #ifdef TCP_SIGNATURE 1015 int 1016 tcp_signature_tdb_attach() 1017 { 1018 return (0); 1019 } 1020 1021 int 1022 tcp_signature_tdb_init(tdbp, xsp, ii) 1023 struct tdb *tdbp; 1024 struct xformsw *xsp; 1025 struct ipsecinit *ii; 1026 { 1027 if ((ii->ii_authkeylen < 1) || (ii->ii_authkeylen > 80)) 1028 return (EINVAL); 1029 1030 tdbp->tdb_amxkey = malloc(ii->ii_authkeylen, M_XDATA, M_NOWAIT); 1031 if (tdbp->tdb_amxkey == NULL) 1032 return (ENOMEM); 1033 bcopy(ii->ii_authkey, tdbp->tdb_amxkey, ii->ii_authkeylen); 1034 tdbp->tdb_amxkeylen = ii->ii_authkeylen; 1035 1036 return (0); 1037 } 1038 1039 int 1040 tcp_signature_tdb_zeroize(tdbp) 1041 struct tdb *tdbp; 1042 { 1043 if (tdbp->tdb_amxkey) { 1044 explicit_bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); 1045 free(tdbp->tdb_amxkey, M_XDATA); 1046 tdbp->tdb_amxkey = NULL; 1047 } 1048 1049 return (0); 1050 } 1051 1052 int 1053 tcp_signature_tdb_input(m, tdbp, skip, protoff) 1054 struct mbuf *m; 1055 struct tdb *tdbp; 1056 int skip, protoff; 1057 { 1058 return (0); 1059 } 1060 1061 int 1062 tcp_signature_tdb_output(m, tdbp, mp, skip, protoff) 1063 struct mbuf *m; 1064 struct tdb *tdbp; 1065 struct mbuf **mp; 1066 int skip, protoff; 1067 { 1068 return (EINVAL); 1069 } 1070 1071 int 1072 tcp_signature_apply(fstate, data, len) 1073 caddr_t fstate; 1074 caddr_t data; 1075 unsigned int len; 1076 { 1077 MD5Update((MD5_CTX *)fstate, (char *)data, len); 1078 return 0; 1079 } 1080 1081 int 1082 tcp_signature(struct tdb *tdb, int af, struct mbuf *m, struct tcphdr *th, 1083 int iphlen, int doswap, char *sig) 1084 { 1085 MD5_CTX ctx; 1086 int len; 1087 struct tcphdr th0; 1088 1089 MD5Init(&ctx); 1090 1091 switch(af) { 1092 case 0: 1093 #ifdef INET 1094 case AF_INET: { 1095 struct ippseudo ippseudo; 1096 struct ip *ip; 1097 1098 ip = mtod(m, struct ip *); 1099 1100 ippseudo.ippseudo_src = ip->ip_src; 1101 ippseudo.ippseudo_dst = ip->ip_dst; 1102 ippseudo.ippseudo_pad = 0; 1103 ippseudo.ippseudo_p = IPPROTO_TCP; 1104 ippseudo.ippseudo_len = htons(m->m_pkthdr.len - iphlen); 1105 1106 MD5Update(&ctx, (char *)&ippseudo, 1107 sizeof(struct ippseudo)); 1108 break; 1109 } 1110 #endif 1111 #ifdef INET6 1112 case AF_INET6: { 1113 struct ip6_hdr_pseudo ip6pseudo; 1114 struct ip6_hdr *ip6; 1115 1116 ip6 = mtod(m, struct ip6_hdr *); 1117 bzero(&ip6pseudo, sizeof(ip6pseudo)); 1118 ip6pseudo.ip6ph_src = ip6->ip6_src; 1119 ip6pseudo.ip6ph_dst = ip6->ip6_dst; 1120 in6_clearscope(&ip6pseudo.ip6ph_src); 1121 in6_clearscope(&ip6pseudo.ip6ph_dst); 1122 ip6pseudo.ip6ph_nxt = IPPROTO_TCP; 1123 ip6pseudo.ip6ph_len = htonl(m->m_pkthdr.len - iphlen); 1124 1125 MD5Update(&ctx, (char *)&ip6pseudo, 1126 sizeof(ip6pseudo)); 1127 break; 1128 } 1129 #endif 1130 } 1131 1132 th0 = *th; 1133 th0.th_sum = 0; 1134 1135 if (doswap) { 1136 HTONL(th0.th_seq); 1137 HTONL(th0.th_ack); 1138 HTONS(th0.th_win); 1139 HTONS(th0.th_urp); 1140 } 1141 MD5Update(&ctx, (char *)&th0, sizeof(th0)); 1142 1143 len = m->m_pkthdr.len - iphlen - th->th_off * sizeof(uint32_t); 1144 1145 if (len > 0 && 1146 m_apply(m, iphlen + th->th_off * sizeof(uint32_t), len, 1147 tcp_signature_apply, (caddr_t)&ctx)) 1148 return (-1); 1149 1150 MD5Update(&ctx, tdb->tdb_amxkey, tdb->tdb_amxkeylen); 1151 MD5Final(sig, &ctx); 1152 1153 return (0); 1154 } 1155 #endif /* TCP_SIGNATURE */ 1156