tcp_timewait.c revision 91357
1/* 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 34 * $FreeBSD: head/sys/netinet/tcp_timewait.c 91357 2002-02-27 05:11:50Z alfred $ 35 */ 36 37#include "opt_compat.h" 38#include "opt_inet6.h" 39#include "opt_ipsec.h" 40#include "opt_tcpdebug.h" 41 42#include <sys/param.h> 43#include <sys/systm.h> 44#include <sys/callout.h> 45#include <sys/kernel.h> 46#include <sys/sysctl.h> 47#include <sys/malloc.h> 48#include <sys/mbuf.h> 49#ifdef INET6 50#include <sys/domain.h> 51#endif 52#include <sys/proc.h> 53#include <sys/socket.h> 54#include <sys/socketvar.h> 55#include <sys/protosw.h> 56#include <sys/random.h> 57 58#include <vm/vm_zone.h> 59 60#include <net/route.h> 61#include <net/if.h> 62 63#define _IP_VHL 64#include <netinet/in.h> 65#include <netinet/in_systm.h> 66#include <netinet/ip.h> 67#ifdef INET6 68#include <netinet/ip6.h> 69#endif 70#include <netinet/in_pcb.h> 71#ifdef INET6 72#include <netinet6/in6_pcb.h> 73#endif 74#include <netinet/in_var.h> 75#include <netinet/ip_var.h> 76#ifdef INET6 77#include <netinet6/ip6_var.h> 78#endif 79#include <netinet/tcp.h> 80#include <netinet/tcp_fsm.h> 81#include <netinet/tcp_seq.h> 82#include <netinet/tcp_timer.h> 83#include <netinet/tcp_var.h> 84#ifdef INET6 85#include <netinet6/tcp6_var.h> 86#endif 87#include <netinet/tcpip.h> 88#ifdef TCPDEBUG 89#include <netinet/tcp_debug.h> 90#endif 91#include <netinet6/ip6protosw.h> 92 93#ifdef IPSEC 94#include <netinet6/ipsec.h> 95#ifdef INET6 96#include <netinet6/ipsec6.h> 97#endif 98#endif /*IPSEC*/ 99 100#include <machine/in_cksum.h> 101#include <sys/md5.h> 102 103int tcp_mssdflt = TCP_MSS; 104SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 105 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size"); 106 107#ifdef INET6 108int tcp_v6mssdflt = TCP6_MSS; 109SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 110 CTLFLAG_RW, &tcp_v6mssdflt , 0, 111 "Default TCP Maximum Segment Size for IPv6"); 112#endif 113 114#if 0 115static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 116SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 117 &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time"); 118#endif 119 120int tcp_do_rfc1323 = 1; 121SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 122 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions"); 123 124int tcp_do_rfc1644 = 0; 125SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 126 &tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions"); 127 128static int tcp_tcbhashsize = 0; 129SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 130 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 131 132static int do_tcpdrain = 1; 133SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 134 "Enable tcp_drain routine for extra help when low on mbufs"); 135 136SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 137 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 138 139static int icmp_may_rst = 1; 140SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 141 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 142 143static int tcp_strict_rfc1948 = 0; 144SYSCTL_INT(_net_inet_tcp, OID_AUTO, strict_rfc1948, CTLFLAG_RW, 145 &tcp_strict_rfc1948, 0, "Determines if RFC1948 is followed exactly"); 146 147static int tcp_isn_reseed_interval = 0; 148SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 149 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 150 151static void tcp_cleartaocache __P((void)); 152static void tcp_notify __P((struct inpcb *, int)); 153 154/* 155 * Target size of TCP PCB hash tables. Must be a power of two. 156 * 157 * Note that this can be overridden by the kernel environment 158 * variable net.inet.tcp.tcbhashsize 159 */ 160#ifndef TCBHASHSIZE 161#define TCBHASHSIZE 512 162#endif 163 164/* 165 * This is the actual shape of what we allocate using the zone 166 * allocator. Doing it this way allows us to protect both structures 167 * using the same generation count, and also eliminates the overhead 168 * of allocating tcpcbs separately. By hiding the structure here, 169 * we avoid changing most of the rest of the code (although it needs 170 * to be changed, eventually, for greater efficiency). 171 */ 172#define ALIGNMENT 32 173#define ALIGNM1 (ALIGNMENT - 1) 174struct inp_tp { 175 union { 176 struct inpcb inp; 177 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 178 } inp_tp_u; 179 struct tcpcb tcb; 180 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl; 181 struct callout inp_tp_delack; 182}; 183#undef ALIGNMENT 184#undef ALIGNM1 185 186/* 187 * Tcp initialization 188 */ 189void 190tcp_init() 191{ 192 int hashsize = TCBHASHSIZE; 193 194 tcp_ccgen = 1; 195 tcp_cleartaocache(); 196 197 tcp_delacktime = TCPTV_DELACK; 198 tcp_keepinit = TCPTV_KEEP_INIT; 199 tcp_keepidle = TCPTV_KEEP_IDLE; 200 tcp_keepintvl = TCPTV_KEEPINTVL; 201 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 202 tcp_msl = TCPTV_MSL; 203 204 LIST_INIT(&tcb); 205 tcbinfo.listhead = &tcb; 206 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 207 if (!powerof2(hashsize)) { 208 printf("WARNING: TCB hash size not a power of 2\n"); 209 hashsize = 512; /* safe default */ 210 } 211 tcp_tcbhashsize = hashsize; 212 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask); 213 tcbinfo.porthashbase = hashinit(hashsize, M_PCB, 214 &tcbinfo.porthashmask); 215 tcbinfo.ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 216 ZONE_INTERRUPT, 0); 217#ifdef INET6 218#define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 219#else /* INET6 */ 220#define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 221#endif /* INET6 */ 222 if (max_protohdr < TCP_MINPROTOHDR) 223 max_protohdr = TCP_MINPROTOHDR; 224 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 225 panic("tcp_init"); 226#undef TCP_MINPROTOHDR 227 228 syncache_init(); 229} 230 231/* 232 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 233 * tcp_template used to store this data in mbufs, but we now recopy it out 234 * of the tcpcb each time to conserve mbufs. 235 */ 236void 237tcp_fillheaders(tp, ip_ptr, tcp_ptr) 238 struct tcpcb *tp; 239 void *ip_ptr; 240 void *tcp_ptr; 241{ 242 struct inpcb *inp = tp->t_inpcb; 243 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 244 245#ifdef INET6 246 if ((inp->inp_vflag & INP_IPV6) != 0) { 247 struct ip6_hdr *ip6; 248 249 ip6 = (struct ip6_hdr *)ip_ptr; 250 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 251 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 252 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 253 (IPV6_VERSION & IPV6_VERSION_MASK); 254 ip6->ip6_nxt = IPPROTO_TCP; 255 ip6->ip6_plen = sizeof(struct tcphdr); 256 ip6->ip6_src = inp->in6p_laddr; 257 ip6->ip6_dst = inp->in6p_faddr; 258 tcp_hdr->th_sum = 0; 259 } else 260#endif 261 { 262 struct ip *ip = (struct ip *) ip_ptr; 263 264 ip->ip_vhl = IP_VHL_BORING; 265 ip->ip_tos = 0; 266 ip->ip_len = 0; 267 ip->ip_id = 0; 268 ip->ip_off = 0; 269 ip->ip_ttl = 0; 270 ip->ip_sum = 0; 271 ip->ip_p = IPPROTO_TCP; 272 ip->ip_src = inp->inp_laddr; 273 ip->ip_dst = inp->inp_faddr; 274 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 275 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 276 } 277 278 tcp_hdr->th_sport = inp->inp_lport; 279 tcp_hdr->th_dport = inp->inp_fport; 280 tcp_hdr->th_seq = 0; 281 tcp_hdr->th_ack = 0; 282 tcp_hdr->th_x2 = 0; 283 tcp_hdr->th_off = 5; 284 tcp_hdr->th_flags = 0; 285 tcp_hdr->th_win = 0; 286 tcp_hdr->th_urp = 0; 287} 288 289/* 290 * Create template to be used to send tcp packets on a connection. 291 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 292 * use for this function is in keepalives, which use tcp_respond. 293 */ 294struct tcptemp * 295tcp_maketemplate(tp) 296 struct tcpcb *tp; 297{ 298 struct mbuf *m; 299 struct tcptemp *n; 300 301 m = m_get(M_DONTWAIT, MT_HEADER); 302 if (m == NULL) 303 return (0); 304 m->m_len = sizeof(struct tcptemp); 305 n = mtod(m, struct tcptemp *); 306 307 tcp_fillheaders(tp, (void *)&n->tt_ipgen, (void *)&n->tt_t); 308 return (n); 309} 310 311/* 312 * Send a single message to the TCP at address specified by 313 * the given TCP/IP header. If m == 0, then we make a copy 314 * of the tcpiphdr at ti and send directly to the addressed host. 315 * This is used to force keep alive messages out using the TCP 316 * template for a connection. If flags are given then we send 317 * a message back to the TCP which originated the * segment ti, 318 * and discard the mbuf containing it and any other attached mbufs. 319 * 320 * In any case the ack and sequence number of the transmitted 321 * segment are as specified by the parameters. 322 * 323 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 324 */ 325void 326tcp_respond(tp, ipgen, th, m, ack, seq, flags) 327 struct tcpcb *tp; 328 void *ipgen; 329 register struct tcphdr *th; 330 register struct mbuf *m; 331 tcp_seq ack, seq; 332 int flags; 333{ 334 register int tlen; 335 int win = 0; 336 struct route *ro = 0; 337 struct route sro; 338 struct ip *ip; 339 struct tcphdr *nth; 340#ifdef INET6 341 struct route_in6 *ro6 = 0; 342 struct route_in6 sro6; 343 struct ip6_hdr *ip6; 344 int isipv6; 345#endif /* INET6 */ 346 int ipflags = 0; 347 348#ifdef INET6 349 isipv6 = IP_VHL_V(((struct ip *)ipgen)->ip_vhl) == 6; 350 ip6 = ipgen; 351#endif /* INET6 */ 352 ip = ipgen; 353 354 if (tp) { 355 if (!(flags & TH_RST)) { 356 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 357 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 358 win = (long)TCP_MAXWIN << tp->rcv_scale; 359 } 360#ifdef INET6 361 if (isipv6) 362 ro6 = &tp->t_inpcb->in6p_route; 363 else 364#endif /* INET6 */ 365 ro = &tp->t_inpcb->inp_route; 366 } else { 367#ifdef INET6 368 if (isipv6) { 369 ro6 = &sro6; 370 bzero(ro6, sizeof *ro6); 371 } else 372#endif /* INET6 */ 373 { 374 ro = &sro; 375 bzero(ro, sizeof *ro); 376 } 377 } 378 if (m == 0) { 379 m = m_gethdr(M_DONTWAIT, MT_HEADER); 380 if (m == NULL) 381 return; 382 tlen = 0; 383 m->m_data += max_linkhdr; 384#ifdef INET6 385 if (isipv6) { 386 bcopy((caddr_t)ip6, mtod(m, caddr_t), 387 sizeof(struct ip6_hdr)); 388 ip6 = mtod(m, struct ip6_hdr *); 389 nth = (struct tcphdr *)(ip6 + 1); 390 } else 391#endif /* INET6 */ 392 { 393 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 394 ip = mtod(m, struct ip *); 395 nth = (struct tcphdr *)(ip + 1); 396 } 397 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 398 flags = TH_ACK; 399 } else { 400 m_freem(m->m_next); 401 m->m_next = 0; 402 m->m_data = (caddr_t)ipgen; 403 /* m_len is set later */ 404 tlen = 0; 405#define xchg(a,b,type) { type t; t=a; a=b; b=t; } 406#ifdef INET6 407 if (isipv6) { 408 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 409 nth = (struct tcphdr *)(ip6 + 1); 410 } else 411#endif /* INET6 */ 412 { 413 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 414 nth = (struct tcphdr *)(ip + 1); 415 } 416 if (th != nth) { 417 /* 418 * this is usually a case when an extension header 419 * exists between the IPv6 header and the 420 * TCP header. 421 */ 422 nth->th_sport = th->th_sport; 423 nth->th_dport = th->th_dport; 424 } 425 xchg(nth->th_dport, nth->th_sport, n_short); 426#undef xchg 427 } 428#ifdef INET6 429 if (isipv6) { 430 ip6->ip6_flow = 0; 431 ip6->ip6_vfc = IPV6_VERSION; 432 ip6->ip6_nxt = IPPROTO_TCP; 433 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 434 tlen)); 435 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 436 } else 437#endif 438 { 439 tlen += sizeof (struct tcpiphdr); 440 ip->ip_len = tlen; 441 ip->ip_ttl = ip_defttl; 442 } 443 m->m_len = tlen; 444 m->m_pkthdr.len = tlen; 445 m->m_pkthdr.rcvif = (struct ifnet *) 0; 446 nth->th_seq = htonl(seq); 447 nth->th_ack = htonl(ack); 448 nth->th_x2 = 0; 449 nth->th_off = sizeof (struct tcphdr) >> 2; 450 nth->th_flags = flags; 451 if (tp) 452 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 453 else 454 nth->th_win = htons((u_short)win); 455 nth->th_urp = 0; 456#ifdef INET6 457 if (isipv6) { 458 nth->th_sum = 0; 459 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 460 sizeof(struct ip6_hdr), 461 tlen - sizeof(struct ip6_hdr)); 462 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 463 ro6 && ro6->ro_rt ? 464 ro6->ro_rt->rt_ifp : 465 NULL); 466 } else 467#endif /* INET6 */ 468 { 469 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 470 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 471 m->m_pkthdr.csum_flags = CSUM_TCP; 472 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 473 } 474#ifdef TCPDEBUG 475 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 476 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 477#endif 478#ifdef IPSEC 479 if (ipsec_setsocket(m, tp ? tp->t_inpcb->inp_socket : NULL) != 0) { 480 m_freem(m); 481 return; 482 } 483#endif 484#ifdef INET6 485 if (isipv6) { 486 (void)ip6_output(m, NULL, ro6, ipflags, NULL, NULL); 487 if (ro6 == &sro6 && ro6->ro_rt) { 488 RTFREE(ro6->ro_rt); 489 ro6->ro_rt = NULL; 490 } 491 } else 492#endif /* INET6 */ 493 { 494 (void) ip_output(m, NULL, ro, ipflags, NULL); 495 if (ro == &sro && ro->ro_rt) { 496 RTFREE(ro->ro_rt); 497 ro->ro_rt = NULL; 498 } 499 } 500} 501 502/* 503 * Create a new TCP control block, making an 504 * empty reassembly queue and hooking it to the argument 505 * protocol control block. The `inp' parameter must have 506 * come from the zone allocator set up in tcp_init(). 507 */ 508struct tcpcb * 509tcp_newtcpcb(inp) 510 struct inpcb *inp; 511{ 512 struct inp_tp *it; 513 register struct tcpcb *tp; 514#ifdef INET6 515 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 516#endif /* INET6 */ 517 518 it = (struct inp_tp *)inp; 519 tp = &it->tcb; 520 bzero((char *) tp, sizeof(struct tcpcb)); 521 LIST_INIT(&tp->t_segq); 522 tp->t_maxseg = tp->t_maxopd = 523#ifdef INET6 524 isipv6 ? tcp_v6mssdflt : 525#endif /* INET6 */ 526 tcp_mssdflt; 527 528 /* Set up our timeouts. */ 529 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt, 0); 530 callout_init(tp->tt_persist = &it->inp_tp_persist, 0); 531 callout_init(tp->tt_keep = &it->inp_tp_keep, 0); 532 callout_init(tp->tt_2msl = &it->inp_tp_2msl, 0); 533 callout_init(tp->tt_delack = &it->inp_tp_delack, 0); 534 535 if (tcp_do_rfc1323) 536 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 537 if (tcp_do_rfc1644) 538 tp->t_flags |= TF_REQ_CC; 539 tp->t_inpcb = inp; /* XXX */ 540 /* 541 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 542 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 543 * reasonable initial retransmit time. 544 */ 545 tp->t_srtt = TCPTV_SRTTBASE; 546 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 547 tp->t_rttmin = TCPTV_MIN; 548 tp->t_rxtcur = TCPTV_RTOBASE; 549 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 550 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 551 tp->t_rcvtime = ticks; 552 /* 553 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 554 * because the socket may be bound to an IPv6 wildcard address, 555 * which may match an IPv4-mapped IPv6 address. 556 */ 557 inp->inp_ip_ttl = ip_defttl; 558 inp->inp_ppcb = (caddr_t)tp; 559 return (tp); /* XXX */ 560} 561 562/* 563 * Drop a TCP connection, reporting 564 * the specified error. If connection is synchronized, 565 * then send a RST to peer. 566 */ 567struct tcpcb * 568tcp_drop(tp, errno) 569 register struct tcpcb *tp; 570 int errno; 571{ 572 struct socket *so = tp->t_inpcb->inp_socket; 573 574 if (TCPS_HAVERCVDSYN(tp->t_state)) { 575 tp->t_state = TCPS_CLOSED; 576 (void) tcp_output(tp); 577 tcpstat.tcps_drops++; 578 } else 579 tcpstat.tcps_conndrops++; 580 if (errno == ETIMEDOUT && tp->t_softerror) 581 errno = tp->t_softerror; 582 so->so_error = errno; 583 return (tcp_close(tp)); 584} 585 586/* 587 * Close a TCP control block: 588 * discard all space held by the tcp 589 * discard internet protocol block 590 * wake up any sleepers 591 */ 592struct tcpcb * 593tcp_close(tp) 594 register struct tcpcb *tp; 595{ 596 register struct tseg_qent *q; 597 struct inpcb *inp = tp->t_inpcb; 598 struct socket *so = inp->inp_socket; 599#ifdef INET6 600 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 601#endif /* INET6 */ 602 register struct rtentry *rt; 603 int dosavessthresh; 604 605 /* 606 * Make sure that all of our timers are stopped before we 607 * delete the PCB. 608 */ 609 callout_stop(tp->tt_rexmt); 610 callout_stop(tp->tt_persist); 611 callout_stop(tp->tt_keep); 612 callout_stop(tp->tt_2msl); 613 callout_stop(tp->tt_delack); 614 615 /* 616 * If we got enough samples through the srtt filter, 617 * save the rtt and rttvar in the routing entry. 618 * 'Enough' is arbitrarily defined as the 16 samples. 619 * 16 samples is enough for the srtt filter to converge 620 * to within 5% of the correct value; fewer samples and 621 * we could save a very bogus rtt. 622 * 623 * Don't update the default route's characteristics and don't 624 * update anything that the user "locked". 625 */ 626 if (tp->t_rttupdated >= 16) { 627 register u_long i = 0; 628#ifdef INET6 629 if (isipv6) { 630 struct sockaddr_in6 *sin6; 631 632 if ((rt = inp->in6p_route.ro_rt) == NULL) 633 goto no_valid_rt; 634 sin6 = (struct sockaddr_in6 *)rt_key(rt); 635 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 636 goto no_valid_rt; 637 } 638 else 639#endif /* INET6 */ 640 if ((rt = inp->inp_route.ro_rt) == NULL || 641 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr 642 == INADDR_ANY) 643 goto no_valid_rt; 644 645 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 646 i = tp->t_srtt * 647 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 648 if (rt->rt_rmx.rmx_rtt && i) 649 /* 650 * filter this update to half the old & half 651 * the new values, converting scale. 652 * See route.h and tcp_var.h for a 653 * description of the scaling constants. 654 */ 655 rt->rt_rmx.rmx_rtt = 656 (rt->rt_rmx.rmx_rtt + i) / 2; 657 else 658 rt->rt_rmx.rmx_rtt = i; 659 tcpstat.tcps_cachedrtt++; 660 } 661 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 662 i = tp->t_rttvar * 663 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 664 if (rt->rt_rmx.rmx_rttvar && i) 665 rt->rt_rmx.rmx_rttvar = 666 (rt->rt_rmx.rmx_rttvar + i) / 2; 667 else 668 rt->rt_rmx.rmx_rttvar = i; 669 tcpstat.tcps_cachedrttvar++; 670 } 671 /* 672 * The old comment here said: 673 * update the pipelimit (ssthresh) if it has been updated 674 * already or if a pipesize was specified & the threshhold 675 * got below half the pipesize. I.e., wait for bad news 676 * before we start updating, then update on both good 677 * and bad news. 678 * 679 * But we want to save the ssthresh even if no pipesize is 680 * specified explicitly in the route, because such 681 * connections still have an implicit pipesize specified 682 * by the global tcp_sendspace. In the absence of a reliable 683 * way to calculate the pipesize, it will have to do. 684 */ 685 i = tp->snd_ssthresh; 686 if (rt->rt_rmx.rmx_sendpipe != 0) 687 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2); 688 else 689 dosavessthresh = (i < so->so_snd.sb_hiwat / 2); 690 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 691 i != 0 && rt->rt_rmx.rmx_ssthresh != 0) 692 || dosavessthresh) { 693 /* 694 * convert the limit from user data bytes to 695 * packets then to packet data bytes. 696 */ 697 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 698 if (i < 2) 699 i = 2; 700 i *= (u_long)(tp->t_maxseg + 701#ifdef INET6 702 (isipv6 ? sizeof (struct ip6_hdr) + 703 sizeof (struct tcphdr) : 704#endif 705 sizeof (struct tcpiphdr) 706#ifdef INET6 707 ) 708#endif 709 ); 710 if (rt->rt_rmx.rmx_ssthresh) 711 rt->rt_rmx.rmx_ssthresh = 712 (rt->rt_rmx.rmx_ssthresh + i) / 2; 713 else 714 rt->rt_rmx.rmx_ssthresh = i; 715 tcpstat.tcps_cachedssthresh++; 716 } 717 } 718 no_valid_rt: 719 /* free the reassembly queue, if any */ 720 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 721 LIST_REMOVE(q, tqe_q); 722 m_freem(q->tqe_m); 723 FREE(q, M_TSEGQ); 724 } 725 inp->inp_ppcb = NULL; 726 soisdisconnected(so); 727#ifdef INET6 728 if (INP_CHECK_SOCKAF(so, AF_INET6)) 729 in6_pcbdetach(inp); 730 else 731#endif /* INET6 */ 732 in_pcbdetach(inp); 733 tcpstat.tcps_closed++; 734 return ((struct tcpcb *)0); 735} 736 737void 738tcp_drain() 739{ 740 if (do_tcpdrain) 741 { 742 struct inpcb *inpb; 743 struct tcpcb *tcpb; 744 struct tseg_qent *te; 745 746 /* 747 * Walk the tcpbs, if existing, and flush the reassembly queue, 748 * if there is one... 749 * XXX: The "Net/3" implementation doesn't imply that the TCP 750 * reassembly queue should be flushed, but in a situation 751 * where we're really low on mbufs, this is potentially 752 * usefull. 753 */ 754 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) { 755 if ((tcpb = intotcpcb(inpb))) { 756 while ((te = LIST_FIRST(&tcpb->t_segq)) 757 != NULL) { 758 LIST_REMOVE(te, tqe_q); 759 m_freem(te->tqe_m); 760 FREE(te, M_TSEGQ); 761 } 762 } 763 } 764 } 765} 766 767/* 768 * Notify a tcp user of an asynchronous error; 769 * store error as soft error, but wake up user 770 * (for now, won't do anything until can select for soft error). 771 * 772 * Do not wake up user since there currently is no mechanism for 773 * reporting soft errors (yet - a kqueue filter may be added). 774 */ 775static void 776tcp_notify(inp, error) 777 struct inpcb *inp; 778 int error; 779{ 780 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 781 782 /* 783 * Ignore some errors if we are hooked up. 784 * If connection hasn't completed, has retransmitted several times, 785 * and receives a second error, give up now. This is better 786 * than waiting a long time to establish a connection that 787 * can never complete. 788 */ 789 if (tp->t_state == TCPS_ESTABLISHED && 790 (error == EHOSTUNREACH || error == ENETUNREACH || 791 error == EHOSTDOWN)) { 792 return; 793 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 794 tp->t_softerror) 795 tcp_drop(tp, error); 796 else 797 tp->t_softerror = error; 798#if 0 799 wakeup((caddr_t) &so->so_timeo); 800 sorwakeup(so); 801 sowwakeup(so); 802#endif 803} 804 805static int 806tcp_pcblist(SYSCTL_HANDLER_ARGS) 807{ 808 int error, i, n, s; 809 struct inpcb *inp, **inp_list; 810 inp_gen_t gencnt; 811 struct xinpgen xig; 812 813 /* 814 * The process of preparing the TCB list is too time-consuming and 815 * resource-intensive to repeat twice on every request. 816 */ 817 if (req->oldptr == 0) { 818 n = tcbinfo.ipi_count; 819 req->oldidx = 2 * (sizeof xig) 820 + (n + n/8) * sizeof(struct xtcpcb); 821 return 0; 822 } 823 824 if (req->newptr != 0) 825 return EPERM; 826 827 /* 828 * OK, now we're committed to doing something. 829 */ 830 s = splnet(); 831 gencnt = tcbinfo.ipi_gencnt; 832 n = tcbinfo.ipi_count; 833 splx(s); 834 835 xig.xig_len = sizeof xig; 836 xig.xig_count = n; 837 xig.xig_gen = gencnt; 838 xig.xig_sogen = so_gencnt; 839 error = SYSCTL_OUT(req, &xig, sizeof xig); 840 if (error) 841 return error; 842 843 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 844 if (inp_list == 0) 845 return ENOMEM; 846 847 s = splnet(); 848 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n; 849 inp = LIST_NEXT(inp, inp_list)) { 850 if (inp->inp_gencnt <= gencnt) { 851 if (cr_cansee(req->td->td_proc->p_ucred, 852 inp->inp_socket->so_cred)) 853 continue; 854 inp_list[i++] = inp; 855 } 856 } 857 splx(s); 858 n = i; 859 860 error = 0; 861 for (i = 0; i < n; i++) { 862 inp = inp_list[i]; 863 if (inp->inp_gencnt <= gencnt) { 864 struct xtcpcb xt; 865 caddr_t inp_ppcb; 866 xt.xt_len = sizeof xt; 867 /* XXX should avoid extra copy */ 868 bcopy(inp, &xt.xt_inp, sizeof *inp); 869 inp_ppcb = inp->inp_ppcb; 870 if (inp_ppcb != NULL) 871 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 872 else 873 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 874 if (inp->inp_socket) 875 sotoxsocket(inp->inp_socket, &xt.xt_socket); 876 error = SYSCTL_OUT(req, &xt, sizeof xt); 877 } 878 } 879 if (!error) { 880 /* 881 * Give the user an updated idea of our state. 882 * If the generation differs from what we told 883 * her before, she knows that something happened 884 * while we were processing this request, and it 885 * might be necessary to retry. 886 */ 887 s = splnet(); 888 xig.xig_gen = tcbinfo.ipi_gencnt; 889 xig.xig_sogen = so_gencnt; 890 xig.xig_count = tcbinfo.ipi_count; 891 splx(s); 892 error = SYSCTL_OUT(req, &xig, sizeof xig); 893 } 894 free(inp_list, M_TEMP); 895 return error; 896} 897 898SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 899 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 900 901static int 902tcp_getcred(SYSCTL_HANDLER_ARGS) 903{ 904 struct xucred xuc; 905 struct sockaddr_in addrs[2]; 906 struct inpcb *inp; 907 int error, s; 908 909 error = suser_xxx(0, req->td->td_proc, PRISON_ROOT); 910 if (error) 911 return (error); 912 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 913 if (error) 914 return (error); 915 s = splnet(); 916 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 917 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 918 if (inp == NULL || inp->inp_socket == NULL) { 919 error = ENOENT; 920 goto out; 921 } 922 error = cr_cansee(req->td->td_proc->p_ucred, inp->inp_socket->so_cred); 923 if (error) 924 goto out; 925 cru2x(inp->inp_socket->so_cred, &xuc); 926 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 927out: 928 splx(s); 929 return (error); 930} 931 932SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 933 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 934 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 935 936#ifdef INET6 937static int 938tcp6_getcred(SYSCTL_HANDLER_ARGS) 939{ 940 struct xucred xuc; 941 struct sockaddr_in6 addrs[2]; 942 struct inpcb *inp; 943 int error, s, mapped = 0; 944 945 error = suser_xxx(0, req->td->td_proc, PRISON_ROOT); 946 if (error) 947 return (error); 948 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 949 if (error) 950 return (error); 951 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 952 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 953 mapped = 1; 954 else 955 return (EINVAL); 956 } 957 s = splnet(); 958 if (mapped == 1) 959 inp = in_pcblookup_hash(&tcbinfo, 960 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 961 addrs[1].sin6_port, 962 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 963 addrs[0].sin6_port, 964 0, NULL); 965 else 966 inp = in6_pcblookup_hash(&tcbinfo, &addrs[1].sin6_addr, 967 addrs[1].sin6_port, 968 &addrs[0].sin6_addr, addrs[0].sin6_port, 969 0, NULL); 970 if (inp == NULL || inp->inp_socket == NULL) { 971 error = ENOENT; 972 goto out; 973 } 974 error = cr_cansee(req->td->td_proc->p_ucred, inp->inp_socket->so_cred); 975 if (error) 976 goto out; 977 cru2x(inp->inp_socket->so_cred, &xuc); 978 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 979out: 980 splx(s); 981 return (error); 982} 983 984SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 985 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 986 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 987#endif 988 989 990void 991tcp_ctlinput(cmd, sa, vip) 992 int cmd; 993 struct sockaddr *sa; 994 void *vip; 995{ 996 struct ip *ip = vip; 997 struct tcphdr *th; 998 struct in_addr faddr; 999 struct inpcb *inp; 1000 struct tcpcb *tp; 1001 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1002 tcp_seq icmp_seq; 1003 int s; 1004 1005 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1006 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1007 return; 1008 1009 if (cmd == PRC_QUENCH) 1010 notify = tcp_quench; 1011 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1012 cmd == PRC_UNREACH_PORT) && ip) 1013 notify = tcp_drop_syn_sent; 1014 else if (cmd == PRC_MSGSIZE) 1015 notify = tcp_mtudisc; 1016 else if (PRC_IS_REDIRECT(cmd)) { 1017 ip = 0; 1018 notify = in_rtchange; 1019 } else if (cmd == PRC_HOSTDEAD) 1020 ip = 0; 1021 else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0) 1022 return; 1023 if (ip) { 1024 s = splnet(); 1025 th = (struct tcphdr *)((caddr_t)ip 1026 + (IP_VHL_HL(ip->ip_vhl) << 2)); 1027 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1028 ip->ip_src, th->th_sport, 0, NULL); 1029 if (inp != NULL && inp->inp_socket != NULL) { 1030 icmp_seq = htonl(th->th_seq); 1031 tp = intotcpcb(inp); 1032 if (SEQ_GEQ(icmp_seq, tp->snd_una) && 1033 SEQ_LT(icmp_seq, tp->snd_max)) 1034 (*notify)(inp, inetctlerrmap[cmd]); 1035 } else { 1036 struct in_conninfo inc; 1037 1038 inc.inc_fport = th->th_dport; 1039 inc.inc_lport = th->th_sport; 1040 inc.inc_faddr = faddr; 1041 inc.inc_laddr = ip->ip_src; 1042#ifdef INET6 1043 inc.inc_isipv6 = 0; 1044#endif 1045 syncache_unreach(&inc, th); 1046 } 1047 splx(s); 1048 } else 1049 in_pcbnotifyall(&tcb, faddr, inetctlerrmap[cmd], notify); 1050} 1051 1052#ifdef INET6 1053void 1054tcp6_ctlinput(cmd, sa, d) 1055 int cmd; 1056 struct sockaddr *sa; 1057 void *d; 1058{ 1059 struct tcphdr th; 1060 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1061 struct ip6_hdr *ip6; 1062 struct mbuf *m; 1063 struct ip6ctlparam *ip6cp = NULL; 1064 const struct sockaddr_in6 *sa6_src = NULL; 1065 int off; 1066 struct tcp_portonly { 1067 u_int16_t th_sport; 1068 u_int16_t th_dport; 1069 } *thp; 1070 1071 if (sa->sa_family != AF_INET6 || 1072 sa->sa_len != sizeof(struct sockaddr_in6)) 1073 return; 1074 1075 if (cmd == PRC_QUENCH) 1076 notify = tcp_quench; 1077 else if (cmd == PRC_MSGSIZE) 1078 notify = tcp_mtudisc; 1079 else if (!PRC_IS_REDIRECT(cmd) && 1080 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1081 return; 1082 1083 /* if the parameter is from icmp6, decode it. */ 1084 if (d != NULL) { 1085 ip6cp = (struct ip6ctlparam *)d; 1086 m = ip6cp->ip6c_m; 1087 ip6 = ip6cp->ip6c_ip6; 1088 off = ip6cp->ip6c_off; 1089 sa6_src = ip6cp->ip6c_src; 1090 } else { 1091 m = NULL; 1092 ip6 = NULL; 1093 off = 0; /* fool gcc */ 1094 sa6_src = &sa6_any; 1095 } 1096 1097 if (ip6) { 1098 struct in_conninfo inc; 1099 /* 1100 * XXX: We assume that when IPV6 is non NULL, 1101 * M and OFF are valid. 1102 */ 1103 1104 /* check if we can safely examine src and dst ports */ 1105 if (m->m_pkthdr.len < off + sizeof(*thp)) 1106 return; 1107 1108 bzero(&th, sizeof(th)); 1109 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1110 1111 in6_pcbnotify(&tcb, sa, th.th_dport, 1112 (struct sockaddr *)ip6cp->ip6c_src, 1113 th.th_sport, cmd, notify); 1114 1115 inc.inc_fport = th.th_dport; 1116 inc.inc_lport = th.th_sport; 1117 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1118 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1119 inc.inc_isipv6 = 1; 1120 syncache_unreach(&inc, &th); 1121 } else 1122 in6_pcbnotify(&tcb, sa, 0, (const struct sockaddr *)sa6_src, 1123 0, cmd, notify); 1124} 1125#endif /* INET6 */ 1126 1127 1128/* 1129 * Following is where TCP initial sequence number generation occurs. 1130 * 1131 * There are two places where we must use initial sequence numbers: 1132 * 1. In SYN-ACK packets. 1133 * 2. In SYN packets. 1134 * 1135 * The ISNs in SYN-ACK packets have no monotonicity requirement, 1136 * and should be as unpredictable as possible to avoid the possibility 1137 * of spoofing and/or connection hijacking. To satisfy this 1138 * requirement, SYN-ACK ISNs are generated via the arc4random() 1139 * function. If exact RFC 1948 compliance is requested via sysctl, 1140 * these ISNs will be generated just like those in SYN packets. 1141 * 1142 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1143 * depends on this property. In addition, these ISNs should be 1144 * unguessable so as to prevent connection hijacking. To satisfy 1145 * the requirements of this situation, the algorithm outlined in 1146 * RFC 1948 is used to generate sequence numbers. 1147 * 1148 * For more information on the theory of operation, please see 1149 * RFC 1948. 1150 * 1151 * Implementation details: 1152 * 1153 * Time is based off the system timer, and is corrected so that it 1154 * increases by one megabyte per second. This allows for proper 1155 * recycling on high speed LANs while still leaving over an hour 1156 * before rollover. 1157 * 1158 * Two sysctls control the generation of ISNs: 1159 * 1160 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1161 * between seeding of isn_secret. This is normally set to zero, 1162 * as reseeding should not be necessary. 1163 * 1164 * net.inet.tcp.strict_rfc1948 controls whether RFC 1948 is followed 1165 * strictly. When strict compliance is requested, reseeding is 1166 * disabled and SYN-ACKs will be generated in the same manner as 1167 * SYNs. Strict mode is disabled by default. 1168 * 1169 */ 1170 1171#define ISN_BYTES_PER_SECOND 1048576 1172 1173u_char isn_secret[32]; 1174int isn_last_reseed; 1175MD5_CTX isn_ctx; 1176 1177tcp_seq 1178tcp_new_isn(tp) 1179 struct tcpcb *tp; 1180{ 1181 u_int32_t md5_buffer[4]; 1182 tcp_seq new_isn; 1183 1184 /* Use arc4random for SYN-ACKs when not in exact RFC1948 mode. */ 1185 if (((tp->t_state == TCPS_LISTEN) || (tp->t_state == TCPS_TIME_WAIT)) 1186 && tcp_strict_rfc1948 == 0) 1187 return arc4random(); 1188 1189 /* Seed if this is the first use, reseed if requested. */ 1190 if ((isn_last_reseed == 0) || 1191 ((tcp_strict_rfc1948 == 0) && (tcp_isn_reseed_interval > 0) && 1192 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1193 < (u_int)ticks))) { 1194 read_random(&isn_secret, sizeof(isn_secret)); 1195 isn_last_reseed = ticks; 1196 } 1197 1198 /* Compute the md5 hash and return the ISN. */ 1199 MD5Init(&isn_ctx); 1200 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1201 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1202#ifdef INET6 1203 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1204 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1205 sizeof(struct in6_addr)); 1206 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1207 sizeof(struct in6_addr)); 1208 } else 1209#endif 1210 { 1211 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1212 sizeof(struct in_addr)); 1213 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1214 sizeof(struct in_addr)); 1215 } 1216 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1217 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1218 new_isn = (tcp_seq) md5_buffer[0]; 1219 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1220 return new_isn; 1221} 1222 1223/* 1224 * When a source quench is received, close congestion window 1225 * to one segment. We will gradually open it again as we proceed. 1226 */ 1227void 1228tcp_quench(inp, errno) 1229 struct inpcb *inp; 1230 int errno; 1231{ 1232 struct tcpcb *tp = intotcpcb(inp); 1233 1234 if (tp) 1235 tp->snd_cwnd = tp->t_maxseg; 1236} 1237 1238/* 1239 * When a specific ICMP unreachable message is received and the 1240 * connection state is SYN-SENT, drop the connection. This behavior 1241 * is controlled by the icmp_may_rst sysctl. 1242 */ 1243void 1244tcp_drop_syn_sent(inp, errno) 1245 struct inpcb *inp; 1246 int errno; 1247{ 1248 struct tcpcb *tp = intotcpcb(inp); 1249 1250 if (tp && tp->t_state == TCPS_SYN_SENT) 1251 tcp_drop(tp, errno); 1252} 1253 1254/* 1255 * When `need fragmentation' ICMP is received, update our idea of the MSS 1256 * based on the new value in the route. Also nudge TCP to send something, 1257 * since we know the packet we just sent was dropped. 1258 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1259 */ 1260void 1261tcp_mtudisc(inp, errno) 1262 struct inpcb *inp; 1263 int errno; 1264{ 1265 struct tcpcb *tp = intotcpcb(inp); 1266 struct rtentry *rt; 1267 struct rmxp_tao *taop; 1268 struct socket *so = inp->inp_socket; 1269 int offered; 1270 int mss; 1271#ifdef INET6 1272 int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1273#endif /* INET6 */ 1274 1275 if (tp) { 1276#ifdef INET6 1277 if (isipv6) 1278 rt = tcp_rtlookup6(&inp->inp_inc); 1279 else 1280#endif /* INET6 */ 1281 rt = tcp_rtlookup(&inp->inp_inc); 1282 if (!rt || !rt->rt_rmx.rmx_mtu) { 1283 tp->t_maxopd = tp->t_maxseg = 1284#ifdef INET6 1285 isipv6 ? tcp_v6mssdflt : 1286#endif /* INET6 */ 1287 tcp_mssdflt; 1288 return; 1289 } 1290 taop = rmx_taop(rt->rt_rmx); 1291 offered = taop->tao_mssopt; 1292 mss = rt->rt_rmx.rmx_mtu - 1293#ifdef INET6 1294 (isipv6 ? 1295 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1296#endif /* INET6 */ 1297 sizeof(struct tcpiphdr) 1298#ifdef INET6 1299 ) 1300#endif /* INET6 */ 1301 ; 1302 1303 if (offered) 1304 mss = min(mss, offered); 1305 /* 1306 * XXX - The above conditional probably violates the TCP 1307 * spec. The problem is that, since we don't know the 1308 * other end's MSS, we are supposed to use a conservative 1309 * default. But, if we do that, then MTU discovery will 1310 * never actually take place, because the conservative 1311 * default is much less than the MTUs typically seen 1312 * on the Internet today. For the moment, we'll sweep 1313 * this under the carpet. 1314 * 1315 * The conservative default might not actually be a problem 1316 * if the only case this occurs is when sending an initial 1317 * SYN with options and data to a host we've never talked 1318 * to before. Then, they will reply with an MSS value which 1319 * will get recorded and the new parameters should get 1320 * recomputed. For Further Study. 1321 */ 1322 if (tp->t_maxopd <= mss) 1323 return; 1324 tp->t_maxopd = mss; 1325 1326 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1327 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1328 mss -= TCPOLEN_TSTAMP_APPA; 1329 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC && 1330 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC) 1331 mss -= TCPOLEN_CC_APPA; 1332#if (MCLBYTES & (MCLBYTES - 1)) == 0 1333 if (mss > MCLBYTES) 1334 mss &= ~(MCLBYTES-1); 1335#else 1336 if (mss > MCLBYTES) 1337 mss = mss / MCLBYTES * MCLBYTES; 1338#endif 1339 if (so->so_snd.sb_hiwat < mss) 1340 mss = so->so_snd.sb_hiwat; 1341 1342 tp->t_maxseg = mss; 1343 1344 tcpstat.tcps_mturesent++; 1345 tp->t_rtttime = 0; 1346 tp->snd_nxt = tp->snd_una; 1347 tcp_output(tp); 1348 } 1349} 1350 1351/* 1352 * Look-up the routing entry to the peer of this inpcb. If no route 1353 * is found and it cannot be allocated the return NULL. This routine 1354 * is called by TCP routines that access the rmx structure and by tcp_mss 1355 * to get the interface MTU. 1356 */ 1357struct rtentry * 1358tcp_rtlookup(inc) 1359 struct in_conninfo *inc; 1360{ 1361 struct route *ro; 1362 struct rtentry *rt; 1363 1364 ro = &inc->inc_route; 1365 rt = ro->ro_rt; 1366 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1367 /* No route yet, so try to acquire one */ 1368 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1369 ro->ro_dst.sa_family = AF_INET; 1370 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1371 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1372 inc->inc_faddr; 1373 rtalloc(ro); 1374 rt = ro->ro_rt; 1375 } 1376 } 1377 return rt; 1378} 1379 1380#ifdef INET6 1381struct rtentry * 1382tcp_rtlookup6(inc) 1383 struct in_conninfo *inc; 1384{ 1385 struct route_in6 *ro6; 1386 struct rtentry *rt; 1387 1388 ro6 = &inc->inc6_route; 1389 rt = ro6->ro_rt; 1390 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1391 /* No route yet, so try to acquire one */ 1392 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1393 ro6->ro_dst.sin6_family = AF_INET6; 1394 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1395 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1396 rtalloc((struct route *)ro6); 1397 rt = ro6->ro_rt; 1398 } 1399 } 1400 return rt; 1401} 1402#endif /* INET6 */ 1403 1404#ifdef IPSEC 1405/* compute ESP/AH header size for TCP, including outer IP header. */ 1406size_t 1407ipsec_hdrsiz_tcp(tp) 1408 struct tcpcb *tp; 1409{ 1410 struct inpcb *inp; 1411 struct mbuf *m; 1412 size_t hdrsiz; 1413 struct ip *ip; 1414#ifdef INET6 1415 struct ip6_hdr *ip6; 1416#endif /* INET6 */ 1417 struct tcphdr *th; 1418 1419 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1420 return 0; 1421 MGETHDR(m, M_DONTWAIT, MT_DATA); 1422 if (!m) 1423 return 0; 1424 1425#ifdef INET6 1426 if ((inp->inp_vflag & INP_IPV6) != 0) { 1427 ip6 = mtod(m, struct ip6_hdr *); 1428 th = (struct tcphdr *)(ip6 + 1); 1429 m->m_pkthdr.len = m->m_len = 1430 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1431 tcp_fillheaders(tp, ip6, th); 1432 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1433 } else 1434#endif /* INET6 */ 1435 { 1436 ip = mtod(m, struct ip *); 1437 th = (struct tcphdr *)(ip + 1); 1438 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1439 tcp_fillheaders(tp, ip, th); 1440 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1441 } 1442 1443 m_free(m); 1444 return hdrsiz; 1445} 1446#endif /*IPSEC*/ 1447 1448/* 1449 * Return a pointer to the cached information about the remote host. 1450 * The cached information is stored in the protocol specific part of 1451 * the route metrics. 1452 */ 1453struct rmxp_tao * 1454tcp_gettaocache(inc) 1455 struct in_conninfo *inc; 1456{ 1457 struct rtentry *rt; 1458 1459#ifdef INET6 1460 if (inc->inc_isipv6) 1461 rt = tcp_rtlookup6(inc); 1462 else 1463#endif /* INET6 */ 1464 rt = tcp_rtlookup(inc); 1465 1466 /* Make sure this is a host route and is up. */ 1467 if (rt == NULL || 1468 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)) 1469 return NULL; 1470 1471 return rmx_taop(rt->rt_rmx); 1472} 1473 1474/* 1475 * Clear all the TAO cache entries, called from tcp_init. 1476 * 1477 * XXX 1478 * This routine is just an empty one, because we assume that the routing 1479 * routing tables are initialized at the same time when TCP, so there is 1480 * nothing in the cache left over. 1481 */ 1482static void 1483tcp_cleartaocache() 1484{ 1485} 1486