tcp_timewait.c revision 100831
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 100831 2002-07-28 19:59:31Z truckman $ 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/uma.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_isn_reseed_interval = 0; 144SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 145 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 146 147static void tcp_cleartaocache(void); 148static struct inpcb *tcp_notify(struct inpcb *, int); 149 150/* 151 * Target size of TCP PCB hash tables. Must be a power of two. 152 * 153 * Note that this can be overridden by the kernel environment 154 * variable net.inet.tcp.tcbhashsize 155 */ 156#ifndef TCBHASHSIZE 157#define TCBHASHSIZE 512 158#endif 159 160/* 161 * This is the actual shape of what we allocate using the zone 162 * allocator. Doing it this way allows us to protect both structures 163 * using the same generation count, and also eliminates the overhead 164 * of allocating tcpcbs separately. By hiding the structure here, 165 * we avoid changing most of the rest of the code (although it needs 166 * to be changed, eventually, for greater efficiency). 167 */ 168#define ALIGNMENT 32 169#define ALIGNM1 (ALIGNMENT - 1) 170struct inp_tp { 171 union { 172 struct inpcb inp; 173 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 174 } inp_tp_u; 175 struct tcpcb tcb; 176 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl; 177 struct callout inp_tp_delack; 178}; 179#undef ALIGNMENT 180#undef ALIGNM1 181 182/* 183 * Tcp initialization 184 */ 185void 186tcp_init() 187{ 188 int hashsize = TCBHASHSIZE; 189 190 tcp_ccgen = 1; 191 tcp_cleartaocache(); 192 193 tcp_delacktime = TCPTV_DELACK; 194 tcp_keepinit = TCPTV_KEEP_INIT; 195 tcp_keepidle = TCPTV_KEEP_IDLE; 196 tcp_keepintvl = TCPTV_KEEPINTVL; 197 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 198 tcp_msl = TCPTV_MSL; 199 tcp_rexmit_min = TCPTV_MIN; 200 tcp_rexmit_slop = TCPTV_CPU_VAR; 201 202 INP_INFO_LOCK_INIT(&tcbinfo, "tcp"); 203 LIST_INIT(&tcb); 204 tcbinfo.listhead = &tcb; 205 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 206 if (!powerof2(hashsize)) { 207 printf("WARNING: TCB hash size not a power of 2\n"); 208 hashsize = 512; /* safe default */ 209 } 210 tcp_tcbhashsize = hashsize; 211 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask); 212 tcbinfo.porthashbase = hashinit(hashsize, M_PCB, 213 &tcbinfo.porthashmask); 214 tcbinfo.ipi_zone = uma_zcreate("tcpcb", sizeof(struct inp_tp), 215 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 216 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 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 = tcp_rexmit_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 INP_INFO_RLOCK(&tcbinfo); 755 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) { 756 INP_LOCK(inpb); 757 if ((tcpb = intotcpcb(inpb))) { 758 while ((te = LIST_FIRST(&tcpb->t_segq)) 759 != NULL) { 760 LIST_REMOVE(te, tqe_q); 761 m_freem(te->tqe_m); 762 FREE(te, M_TSEGQ); 763 } 764 } 765 INP_UNLOCK(inpb); 766 } 767 INP_INFO_RUNLOCK(&tcbinfo); 768 } 769} 770 771/* 772 * Notify a tcp user of an asynchronous error; 773 * store error as soft error, but wake up user 774 * (for now, won't do anything until can select for soft error). 775 * 776 * Do not wake up user since there currently is no mechanism for 777 * reporting soft errors (yet - a kqueue filter may be added). 778 */ 779static struct inpcb * 780tcp_notify(inp, error) 781 struct inpcb *inp; 782 int error; 783{ 784 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 785 786 /* 787 * Ignore some errors if we are hooked up. 788 * If connection hasn't completed, has retransmitted several times, 789 * and receives a second error, give up now. This is better 790 * than waiting a long time to establish a connection that 791 * can never complete. 792 */ 793 if (tp->t_state == TCPS_ESTABLISHED && 794 (error == EHOSTUNREACH || error == ENETUNREACH || 795 error == EHOSTDOWN)) { 796 return inp; 797 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 798 tp->t_softerror) { 799 tcp_drop(tp, error); 800 return (struct inpcb *)0; 801 } else { 802 tp->t_softerror = error; 803 return inp; 804 } 805#if 0 806 wakeup((caddr_t) &so->so_timeo); 807 sorwakeup(so); 808 sowwakeup(so); 809#endif 810} 811 812static int 813tcp_pcblist(SYSCTL_HANDLER_ARGS) 814{ 815 int error, i, n, s; 816 struct inpcb *inp, **inp_list; 817 inp_gen_t gencnt; 818 struct xinpgen xig; 819 820 /* 821 * The process of preparing the TCB list is too time-consuming and 822 * resource-intensive to repeat twice on every request. 823 */ 824 if (req->oldptr == 0) { 825 n = tcbinfo.ipi_count; 826 req->oldidx = 2 * (sizeof xig) 827 + (n + n/8) * sizeof(struct xtcpcb); 828 return 0; 829 } 830 831 if (req->newptr != 0) 832 return EPERM; 833 834 /* 835 * OK, now we're committed to doing something. 836 */ 837 s = splnet(); 838 INP_INFO_RLOCK(&tcbinfo); 839 gencnt = tcbinfo.ipi_gencnt; 840 n = tcbinfo.ipi_count; 841 INP_INFO_RUNLOCK(&tcbinfo); 842 splx(s); 843 844 sysctl_wire_old_buffer(req, 2 * (sizeof xig) 845 + n * sizeof(struct xtcpcb)); 846 847 xig.xig_len = sizeof xig; 848 xig.xig_count = n; 849 xig.xig_gen = gencnt; 850 xig.xig_sogen = so_gencnt; 851 error = SYSCTL_OUT(req, &xig, sizeof xig); 852 if (error) 853 return error; 854 855 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 856 if (inp_list == 0) 857 return ENOMEM; 858 859 s = splnet(); 860 INP_INFO_RLOCK(&tcbinfo); 861 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n; 862 inp = LIST_NEXT(inp, inp_list)) { 863 INP_LOCK(inp); 864 if (inp->inp_gencnt <= gencnt && 865 cr_canseesocket(req->td->td_ucred, inp->inp_socket) == 0) 866 inp_list[i++] = inp; 867 INP_UNLOCK(inp); 868 } 869 INP_INFO_RUNLOCK(&tcbinfo); 870 splx(s); 871 n = i; 872 873 error = 0; 874 for (i = 0; i < n; i++) { 875 inp = inp_list[i]; 876 INP_LOCK(inp); 877 if (inp->inp_gencnt <= gencnt) { 878 struct xtcpcb xt; 879 caddr_t inp_ppcb; 880 xt.xt_len = sizeof xt; 881 /* XXX should avoid extra copy */ 882 bcopy(inp, &xt.xt_inp, sizeof *inp); 883 inp_ppcb = inp->inp_ppcb; 884 if (inp_ppcb != NULL) 885 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 886 else 887 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 888 if (inp->inp_socket) 889 sotoxsocket(inp->inp_socket, &xt.xt_socket); 890 error = SYSCTL_OUT(req, &xt, sizeof xt); 891 } 892 INP_UNLOCK(inp); 893 } 894 if (!error) { 895 /* 896 * Give the user an updated idea of our state. 897 * If the generation differs from what we told 898 * her before, she knows that something happened 899 * while we were processing this request, and it 900 * might be necessary to retry. 901 */ 902 s = splnet(); 903 INP_INFO_RLOCK(&tcbinfo); 904 xig.xig_gen = tcbinfo.ipi_gencnt; 905 xig.xig_sogen = so_gencnt; 906 xig.xig_count = tcbinfo.ipi_count; 907 INP_INFO_RUNLOCK(&tcbinfo); 908 splx(s); 909 error = SYSCTL_OUT(req, &xig, sizeof xig); 910 } 911 free(inp_list, M_TEMP); 912 return error; 913} 914 915SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 916 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 917 918static int 919tcp_getcred(SYSCTL_HANDLER_ARGS) 920{ 921 struct xucred xuc; 922 struct sockaddr_in addrs[2]; 923 struct inpcb *inp; 924 int error, s; 925 926 error = suser_cred(req->td->td_ucred, PRISON_ROOT); 927 if (error) 928 return (error); 929 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 930 if (error) 931 return (error); 932 s = splnet(); 933 INP_INFO_RLOCK(&tcbinfo); 934 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 935 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 936 if (inp == NULL) { 937 error = ENOENT; 938 goto outunlocked; 939 } 940 INP_LOCK(inp); 941 if (inp->inp_socket == NULL) { 942 error = ENOENT; 943 goto out; 944 } 945 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 946 if (error) 947 goto out; 948 cru2x(inp->inp_socket->so_cred, &xuc); 949out: 950 INP_UNLOCK(inp); 951outunlocked: 952 INP_INFO_RUNLOCK(&tcbinfo); 953 splx(s); 954 if (error == 0) 955 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 956 return (error); 957} 958 959SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 960 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 961 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 962 963#ifdef INET6 964static int 965tcp6_getcred(SYSCTL_HANDLER_ARGS) 966{ 967 struct xucred xuc; 968 struct sockaddr_in6 addrs[2]; 969 struct inpcb *inp; 970 int error, s, mapped = 0; 971 972 error = suser_cred(req->td->td_ucred, PRISON_ROOT); 973 if (error) 974 return (error); 975 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 976 if (error) 977 return (error); 978 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 979 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 980 mapped = 1; 981 else 982 return (EINVAL); 983 } 984 s = splnet(); 985 INP_INFO_RLOCK(&tcbinfo); 986 if (mapped == 1) 987 inp = in_pcblookup_hash(&tcbinfo, 988 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 989 addrs[1].sin6_port, 990 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 991 addrs[0].sin6_port, 992 0, NULL); 993 else 994 inp = in6_pcblookup_hash(&tcbinfo, &addrs[1].sin6_addr, 995 addrs[1].sin6_port, 996 &addrs[0].sin6_addr, addrs[0].sin6_port, 997 0, NULL); 998 if (inp == NULL) { 999 error = ENOENT; 1000 goto outunlocked; 1001 } 1002 INP_LOCK(inp); 1003 if (inp->inp_socket == NULL) { 1004 error = ENOENT; 1005 goto out; 1006 } 1007 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1008 if (error) 1009 goto out; 1010 cru2x(inp->inp_socket->so_cred, &xuc); 1011out: 1012 INP_UNLOCK(inp); 1013outunlocked: 1014 INP_INFO_RUNLOCK(&tcbinfo); 1015 splx(s); 1016 if (error == 0) 1017 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1018 return (error); 1019} 1020 1021SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1022 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1023 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1024#endif 1025 1026 1027void 1028tcp_ctlinput(cmd, sa, vip) 1029 int cmd; 1030 struct sockaddr *sa; 1031 void *vip; 1032{ 1033 struct ip *ip = vip; 1034 struct tcphdr *th; 1035 struct in_addr faddr; 1036 struct inpcb *inp; 1037 struct tcpcb *tp; 1038 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1039 tcp_seq icmp_seq; 1040 int s; 1041 1042 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1043 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1044 return; 1045 1046 if (cmd == PRC_QUENCH) 1047 notify = tcp_quench; 1048 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1049 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1050 notify = tcp_drop_syn_sent; 1051 else if (cmd == PRC_MSGSIZE) 1052 notify = tcp_mtudisc; 1053 else if (PRC_IS_REDIRECT(cmd)) { 1054 ip = 0; 1055 notify = in_rtchange; 1056 } else if (cmd == PRC_HOSTDEAD) 1057 ip = 0; 1058 else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0) 1059 return; 1060 if (ip) { 1061 s = splnet(); 1062 th = (struct tcphdr *)((caddr_t)ip 1063 + (IP_VHL_HL(ip->ip_vhl) << 2)); 1064 INP_INFO_WLOCK(&tcbinfo); 1065 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1066 ip->ip_src, th->th_sport, 0, NULL); 1067 if (inp != NULL) { 1068 INP_LOCK(inp); 1069 if (inp->inp_socket != NULL) { 1070 icmp_seq = htonl(th->th_seq); 1071 tp = intotcpcb(inp); 1072 if (SEQ_GEQ(icmp_seq, tp->snd_una) && 1073 SEQ_LT(icmp_seq, tp->snd_max)) 1074 inp = (*notify)(inp, inetctlerrmap[cmd]); 1075 } 1076 if (inp) 1077 INP_UNLOCK(inp); 1078 } else { 1079 struct in_conninfo inc; 1080 1081 inc.inc_fport = th->th_dport; 1082 inc.inc_lport = th->th_sport; 1083 inc.inc_faddr = faddr; 1084 inc.inc_laddr = ip->ip_src; 1085#ifdef INET6 1086 inc.inc_isipv6 = 0; 1087#endif 1088 syncache_unreach(&inc, th); 1089 } 1090 INP_INFO_WUNLOCK(&tcbinfo); 1091 splx(s); 1092 } else 1093 in_pcbnotifyall(&tcbinfo, faddr, inetctlerrmap[cmd], notify); 1094} 1095 1096#ifdef INET6 1097void 1098tcp6_ctlinput(cmd, sa, d) 1099 int cmd; 1100 struct sockaddr *sa; 1101 void *d; 1102{ 1103 struct tcphdr th; 1104 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1105 struct ip6_hdr *ip6; 1106 struct mbuf *m; 1107 struct ip6ctlparam *ip6cp = NULL; 1108 const struct sockaddr_in6 *sa6_src = NULL; 1109 int off; 1110 struct tcp_portonly { 1111 u_int16_t th_sport; 1112 u_int16_t th_dport; 1113 } *thp; 1114 1115 if (sa->sa_family != AF_INET6 || 1116 sa->sa_len != sizeof(struct sockaddr_in6)) 1117 return; 1118 1119 if (cmd == PRC_QUENCH) 1120 notify = tcp_quench; 1121 else if (cmd == PRC_MSGSIZE) 1122 notify = tcp_mtudisc; 1123 else if (!PRC_IS_REDIRECT(cmd) && 1124 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1125 return; 1126 1127 /* if the parameter is from icmp6, decode it. */ 1128 if (d != NULL) { 1129 ip6cp = (struct ip6ctlparam *)d; 1130 m = ip6cp->ip6c_m; 1131 ip6 = ip6cp->ip6c_ip6; 1132 off = ip6cp->ip6c_off; 1133 sa6_src = ip6cp->ip6c_src; 1134 } else { 1135 m = NULL; 1136 ip6 = NULL; 1137 off = 0; /* fool gcc */ 1138 sa6_src = &sa6_any; 1139 } 1140 1141 if (ip6) { 1142 struct in_conninfo inc; 1143 /* 1144 * XXX: We assume that when IPV6 is non NULL, 1145 * M and OFF are valid. 1146 */ 1147 1148 /* check if we can safely examine src and dst ports */ 1149 if (m->m_pkthdr.len < off + sizeof(*thp)) 1150 return; 1151 1152 bzero(&th, sizeof(th)); 1153 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1154 1155 in6_pcbnotify(&tcb, sa, th.th_dport, 1156 (struct sockaddr *)ip6cp->ip6c_src, 1157 th.th_sport, cmd, notify); 1158 1159 inc.inc_fport = th.th_dport; 1160 inc.inc_lport = th.th_sport; 1161 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1162 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1163 inc.inc_isipv6 = 1; 1164 syncache_unreach(&inc, &th); 1165 } else 1166 in6_pcbnotify(&tcb, sa, 0, (const struct sockaddr *)sa6_src, 1167 0, cmd, notify); 1168} 1169#endif /* INET6 */ 1170 1171 1172/* 1173 * Following is where TCP initial sequence number generation occurs. 1174 * 1175 * There are two places where we must use initial sequence numbers: 1176 * 1. In SYN-ACK packets. 1177 * 2. In SYN packets. 1178 * 1179 * All ISNs for SYN-ACK packets are generated by the syncache. See 1180 * tcp_syncache.c for details. 1181 * 1182 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1183 * depends on this property. In addition, these ISNs should be 1184 * unguessable so as to prevent connection hijacking. To satisfy 1185 * the requirements of this situation, the algorithm outlined in 1186 * RFC 1948 is used to generate sequence numbers. 1187 * 1188 * Implementation details: 1189 * 1190 * Time is based off the system timer, and is corrected so that it 1191 * increases by one megabyte per second. This allows for proper 1192 * recycling on high speed LANs while still leaving over an hour 1193 * before rollover. 1194 * 1195 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1196 * between seeding of isn_secret. This is normally set to zero, 1197 * as reseeding should not be necessary. 1198 * 1199 */ 1200 1201#define ISN_BYTES_PER_SECOND 1048576 1202 1203u_char isn_secret[32]; 1204int isn_last_reseed; 1205MD5_CTX isn_ctx; 1206 1207tcp_seq 1208tcp_new_isn(tp) 1209 struct tcpcb *tp; 1210{ 1211 u_int32_t md5_buffer[4]; 1212 tcp_seq new_isn; 1213 1214 /* Seed if this is the first use, reseed if requested. */ 1215 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1216 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1217 < (u_int)ticks))) { 1218 read_random(&isn_secret, sizeof(isn_secret)); 1219 isn_last_reseed = ticks; 1220 } 1221 1222 /* Compute the md5 hash and return the ISN. */ 1223 MD5Init(&isn_ctx); 1224 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1225 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1226#ifdef INET6 1227 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1228 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1229 sizeof(struct in6_addr)); 1230 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1231 sizeof(struct in6_addr)); 1232 } else 1233#endif 1234 { 1235 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1236 sizeof(struct in_addr)); 1237 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1238 sizeof(struct in_addr)); 1239 } 1240 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1241 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1242 new_isn = (tcp_seq) md5_buffer[0]; 1243 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1244 return new_isn; 1245} 1246 1247/* 1248 * When a source quench is received, close congestion window 1249 * to one segment. We will gradually open it again as we proceed. 1250 */ 1251struct inpcb * 1252tcp_quench(inp, errno) 1253 struct inpcb *inp; 1254 int errno; 1255{ 1256 struct tcpcb *tp = intotcpcb(inp); 1257 1258 if (tp) 1259 tp->snd_cwnd = tp->t_maxseg; 1260 return (inp); 1261} 1262 1263/* 1264 * When a specific ICMP unreachable message is received and the 1265 * connection state is SYN-SENT, drop the connection. This behavior 1266 * is controlled by the icmp_may_rst sysctl. 1267 */ 1268struct inpcb * 1269tcp_drop_syn_sent(inp, errno) 1270 struct inpcb *inp; 1271 int errno; 1272{ 1273 struct tcpcb *tp = intotcpcb(inp); 1274 1275 if (tp && tp->t_state == TCPS_SYN_SENT) { 1276 tcp_drop(tp, errno); 1277 return (struct inpcb *)0; 1278 } 1279 return inp; 1280} 1281 1282/* 1283 * When `need fragmentation' ICMP is received, update our idea of the MSS 1284 * based on the new value in the route. Also nudge TCP to send something, 1285 * since we know the packet we just sent was dropped. 1286 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1287 */ 1288struct inpcb * 1289tcp_mtudisc(inp, errno) 1290 struct inpcb *inp; 1291 int errno; 1292{ 1293 struct tcpcb *tp = intotcpcb(inp); 1294 struct rtentry *rt; 1295 struct rmxp_tao *taop; 1296 struct socket *so = inp->inp_socket; 1297 int offered; 1298 int mss; 1299#ifdef INET6 1300 int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1301#endif /* INET6 */ 1302 1303 if (tp) { 1304#ifdef INET6 1305 if (isipv6) 1306 rt = tcp_rtlookup6(&inp->inp_inc); 1307 else 1308#endif /* INET6 */ 1309 rt = tcp_rtlookup(&inp->inp_inc); 1310 if (!rt || !rt->rt_rmx.rmx_mtu) { 1311 tp->t_maxopd = tp->t_maxseg = 1312#ifdef INET6 1313 isipv6 ? tcp_v6mssdflt : 1314#endif /* INET6 */ 1315 tcp_mssdflt; 1316 return inp; 1317 } 1318 taop = rmx_taop(rt->rt_rmx); 1319 offered = taop->tao_mssopt; 1320 mss = rt->rt_rmx.rmx_mtu - 1321#ifdef INET6 1322 (isipv6 ? 1323 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1324#endif /* INET6 */ 1325 sizeof(struct tcpiphdr) 1326#ifdef INET6 1327 ) 1328#endif /* INET6 */ 1329 ; 1330 1331 if (offered) 1332 mss = min(mss, offered); 1333 /* 1334 * XXX - The above conditional probably violates the TCP 1335 * spec. The problem is that, since we don't know the 1336 * other end's MSS, we are supposed to use a conservative 1337 * default. But, if we do that, then MTU discovery will 1338 * never actually take place, because the conservative 1339 * default is much less than the MTUs typically seen 1340 * on the Internet today. For the moment, we'll sweep 1341 * this under the carpet. 1342 * 1343 * The conservative default might not actually be a problem 1344 * if the only case this occurs is when sending an initial 1345 * SYN with options and data to a host we've never talked 1346 * to before. Then, they will reply with an MSS value which 1347 * will get recorded and the new parameters should get 1348 * recomputed. For Further Study. 1349 */ 1350 if (tp->t_maxopd <= mss) 1351 return inp; 1352 tp->t_maxopd = mss; 1353 1354 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1355 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1356 mss -= TCPOLEN_TSTAMP_APPA; 1357 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC && 1358 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC) 1359 mss -= TCPOLEN_CC_APPA; 1360#if (MCLBYTES & (MCLBYTES - 1)) == 0 1361 if (mss > MCLBYTES) 1362 mss &= ~(MCLBYTES-1); 1363#else 1364 if (mss > MCLBYTES) 1365 mss = mss / MCLBYTES * MCLBYTES; 1366#endif 1367 if (so->so_snd.sb_hiwat < mss) 1368 mss = so->so_snd.sb_hiwat; 1369 1370 tp->t_maxseg = mss; 1371 1372 tcpstat.tcps_mturesent++; 1373 tp->t_rtttime = 0; 1374 tp->snd_nxt = tp->snd_una; 1375 tcp_output(tp); 1376 } 1377 return inp; 1378} 1379 1380/* 1381 * Look-up the routing entry to the peer of this inpcb. If no route 1382 * is found and it cannot be allocated the return NULL. This routine 1383 * is called by TCP routines that access the rmx structure and by tcp_mss 1384 * to get the interface MTU. 1385 */ 1386struct rtentry * 1387tcp_rtlookup(inc) 1388 struct in_conninfo *inc; 1389{ 1390 struct route *ro; 1391 struct rtentry *rt; 1392 1393 ro = &inc->inc_route; 1394 rt = ro->ro_rt; 1395 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1396 /* No route yet, so try to acquire one */ 1397 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1398 ro->ro_dst.sa_family = AF_INET; 1399 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1400 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1401 inc->inc_faddr; 1402 rtalloc(ro); 1403 rt = ro->ro_rt; 1404 } 1405 } 1406 return rt; 1407} 1408 1409#ifdef INET6 1410struct rtentry * 1411tcp_rtlookup6(inc) 1412 struct in_conninfo *inc; 1413{ 1414 struct route_in6 *ro6; 1415 struct rtentry *rt; 1416 1417 ro6 = &inc->inc6_route; 1418 rt = ro6->ro_rt; 1419 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1420 /* No route yet, so try to acquire one */ 1421 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1422 ro6->ro_dst.sin6_family = AF_INET6; 1423 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1424 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1425 rtalloc((struct route *)ro6); 1426 rt = ro6->ro_rt; 1427 } 1428 } 1429 return rt; 1430} 1431#endif /* INET6 */ 1432 1433#ifdef IPSEC 1434/* compute ESP/AH header size for TCP, including outer IP header. */ 1435size_t 1436ipsec_hdrsiz_tcp(tp) 1437 struct tcpcb *tp; 1438{ 1439 struct inpcb *inp; 1440 struct mbuf *m; 1441 size_t hdrsiz; 1442 struct ip *ip; 1443#ifdef INET6 1444 struct ip6_hdr *ip6; 1445#endif /* INET6 */ 1446 struct tcphdr *th; 1447 1448 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1449 return 0; 1450 MGETHDR(m, M_DONTWAIT, MT_DATA); 1451 if (!m) 1452 return 0; 1453 1454#ifdef INET6 1455 if ((inp->inp_vflag & INP_IPV6) != 0) { 1456 ip6 = mtod(m, struct ip6_hdr *); 1457 th = (struct tcphdr *)(ip6 + 1); 1458 m->m_pkthdr.len = m->m_len = 1459 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1460 tcp_fillheaders(tp, ip6, th); 1461 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1462 } else 1463#endif /* INET6 */ 1464 { 1465 ip = mtod(m, struct ip *); 1466 th = (struct tcphdr *)(ip + 1); 1467 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1468 tcp_fillheaders(tp, ip, th); 1469 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1470 } 1471 1472 m_free(m); 1473 return hdrsiz; 1474} 1475#endif /*IPSEC*/ 1476 1477/* 1478 * Return a pointer to the cached information about the remote host. 1479 * The cached information is stored in the protocol specific part of 1480 * the route metrics. 1481 */ 1482struct rmxp_tao * 1483tcp_gettaocache(inc) 1484 struct in_conninfo *inc; 1485{ 1486 struct rtentry *rt; 1487 1488#ifdef INET6 1489 if (inc->inc_isipv6) 1490 rt = tcp_rtlookup6(inc); 1491 else 1492#endif /* INET6 */ 1493 rt = tcp_rtlookup(inc); 1494 1495 /* Make sure this is a host route and is up. */ 1496 if (rt == NULL || 1497 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)) 1498 return NULL; 1499 1500 return rmx_taop(rt->rt_rmx); 1501} 1502 1503/* 1504 * Clear all the TAO cache entries, called from tcp_init. 1505 * 1506 * XXX 1507 * This routine is just an empty one, because we assume that the routing 1508 * routing tables are initialized at the same time when TCP, so there is 1509 * nothing in the cache left over. 1510 */ 1511static void 1512tcp_cleartaocache() 1513{ 1514} 1515