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 * $FreeBSD$ 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> 102 103 int tcp_mssdflt = TCP_MSS; 104 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 105 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size"); 106 107 #ifdef INET6 108 int tcp_v6mssdflt = TCP6_MSS; 109 SYSCTL_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 0 115 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 116 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 117 &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time"); 118 #endif 119 120 int tcp_do_rfc1323 = 1; 121 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 122 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions"); 123 124 int tcp_do_rfc1644 = 0; 125 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 126 &tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions"); 127 128 static int tcp_tcbhashsize = 0; 129 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 130 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 131 132 static int do_tcpdrain = 1; 133 SYSCTL_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"); 135 136 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 137 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 138 139 static int icmp_may_rst = 1; 140 SYSCTL_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"); 142 143 static int tcp_strict_rfc1948 = 0; 144 SYSCTL_INT(_net_inet_tcp, OID_AUTO, strict_rfc1948, CTLFLAG_RW, 145 &tcp_strict_rfc1948, 0, "Determines if RFC1948 is followed exactly"); 146 147 static int tcp_isn_reseed_interval = 0; 148 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 149 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 150 151 static void tcp_cleartaocache __P((void)); 152 static 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) 174 struct 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 */ 189 void 190 tcp_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 */ 236 void 237 tcp_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 */ 294 struct tcptemp * 295 tcp_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 */ 325 void 326 tcp_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_plen = htons((u_short)(sizeof (struct tcphdr) + 431 tlen)); 432 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 433 } else 434 #endif 435 { 436 tlen += sizeof (struct tcpiphdr); 437 ip->ip_len = tlen; 438 ip->ip_ttl = ip_defttl; 439 } 440 m->m_len = tlen; 441 m->m_pkthdr.len = tlen; 442 m->m_pkthdr.rcvif = (struct ifnet *) 0; 443 nth->th_seq = htonl(seq); 444 nth->th_ack = htonl(ack); 445 nth->th_x2 = 0; 446 nth->th_off = sizeof (struct tcphdr) >> 2; 447 nth->th_flags = flags; 448 if (tp) 449 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 450 else 451 nth->th_win = htons((u_short)win); 452 nth->th_urp = 0; 453 #ifdef INET6 454 if (isipv6) { 455 nth->th_sum = 0; 456 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 457 sizeof(struct ip6_hdr), 458 tlen - sizeof(struct ip6_hdr)); 459 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 460 ro6 && ro6->ro_rt ? 461 ro6->ro_rt->rt_ifp : 462 NULL); 463 } else 464 #endif /* INET6 */ 465 { 466 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 467 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 468 m->m_pkthdr.csum_flags = CSUM_TCP; 469 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 470 } 471 #ifdef TCPDEBUG 472 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 473 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 474 #endif 475 #ifdef IPSEC 476 if (ipsec_setsocket(m, tp ? tp->t_inpcb->inp_socket : NULL) != 0) { 477 m_freem(m); 478 return; 479 } 480 #endif 481 #ifdef INET6 482 if (isipv6) { 483 (void)ip6_output(m, NULL, ro6, ipflags, NULL, NULL); 484 if (ro6 == &sro6 && ro6->ro_rt) { 485 RTFREE(ro6->ro_rt); 486 ro6->ro_rt = NULL; 487 } 488 } else 489 #endif /* INET6 */ 490 { 491 (void) ip_output(m, NULL, ro, ipflags, NULL); 492 if (ro == &sro && ro->ro_rt) { 493 RTFREE(ro->ro_rt); 494 ro->ro_rt = NULL; 495 } 496 } 497 } 498 499 /* 500 * Create a new TCP control block, making an 501 * empty reassembly queue and hooking it to the argument 502 * protocol control block. The `inp' parameter must have 503 * come from the zone allocator set up in tcp_init(). 504 */ 505 struct tcpcb * 506 tcp_newtcpcb(inp) 507 struct inpcb *inp; 508 { 509 struct inp_tp *it; 510 register struct tcpcb *tp; 511 #ifdef INET6 512 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 513 #endif /* INET6 */ 514 515 it = (struct inp_tp *)inp; 516 tp = &it->tcb; 517 bzero((char *) tp, sizeof(struct tcpcb)); 518 LIST_INIT(&tp->t_segq); 519 tp->t_maxseg = tp->t_maxopd = 520 #ifdef INET6 521 isipv6 ? tcp_v6mssdflt : 522 #endif /* INET6 */ 523 tcp_mssdflt; 524 525 /* Set up our timeouts. */ 526 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt, 0); 527 callout_init(tp->tt_persist = &it->inp_tp_persist, 0); 528 callout_init(tp->tt_keep = &it->inp_tp_keep, 0); 529 callout_init(tp->tt_2msl = &it->inp_tp_2msl, 0); 530 callout_init(tp->tt_delack = &it->inp_tp_delack, 0); 531 532 if (tcp_do_rfc1323) 533 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 534 if (tcp_do_rfc1644) 535 tp->t_flags |= TF_REQ_CC; 536 tp->t_inpcb = inp; /* XXX */ 537 /* 538 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 539 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 540 * reasonable initial retransmit time. 541 */ 542 tp->t_srtt = TCPTV_SRTTBASE; 543 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 544 tp->t_rttmin = TCPTV_MIN; 545 tp->t_rxtcur = TCPTV_RTOBASE; 546 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 547 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 548 tp->t_rcvtime = ticks; 549 /* 550 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 551 * because the socket may be bound to an IPv6 wildcard address, 552 * which may match an IPv4-mapped IPv6 address. 553 */ 554 inp->inp_ip_ttl = ip_defttl; 555 inp->inp_ppcb = (caddr_t)tp; 556 return (tp); /* XXX */ 557 } 558 559 /* 560 * Drop a TCP connection, reporting 561 * the specified error. If connection is synchronized, 562 * then send a RST to peer. 563 */ 564 struct tcpcb * 565 tcp_drop(tp, errno) 566 register struct tcpcb *tp; 567 int errno; 568 { 569 struct socket *so = tp->t_inpcb->inp_socket; 570 571 if (TCPS_HAVERCVDSYN(tp->t_state)) { 572 tp->t_state = TCPS_CLOSED; 573 (void) tcp_output(tp); 574 tcpstat.tcps_drops++; 575 } else 576 tcpstat.tcps_conndrops++; 577 if (errno == ETIMEDOUT && tp->t_softerror) 578 errno = tp->t_softerror; 579 so->so_error = errno; 580 return (tcp_close(tp)); 581 } 582 583 /* 584 * Close a TCP control block: 585 * discard all space held by the tcp 586 * discard internet protocol block 587 * wake up any sleepers 588 */ 589 struct tcpcb * 590 tcp_close(tp) 591 register struct tcpcb *tp; 592 { 593 register struct tseg_qent *q; 594 struct inpcb *inp = tp->t_inpcb; 595 struct socket *so = inp->inp_socket; 596 #ifdef INET6 597 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 598 #endif /* INET6 */ 599 register struct rtentry *rt; 600 int dosavessthresh; 601 602 /* 603 * Make sure that all of our timers are stopped before we 604 * delete the PCB. 605 */ 606 callout_stop(tp->tt_rexmt); 607 callout_stop(tp->tt_persist); 608 callout_stop(tp->tt_keep); 609 callout_stop(tp->tt_2msl); 610 callout_stop(tp->tt_delack); 611 612 /* 613 * If we got enough samples through the srtt filter, 614 * save the rtt and rttvar in the routing entry. 615 * 'Enough' is arbitrarily defined as the 16 samples. 616 * 16 samples is enough for the srtt filter to converge 617 * to within 5% of the correct value; fewer samples and 618 * we could save a very bogus rtt. 619 * 620 * Don't update the default route's characteristics and don't 621 * update anything that the user "locked". 622 */ 623 if (tp->t_rttupdated >= 16) { 624 register u_long i = 0; 625 #ifdef INET6 626 if (isipv6) { 627 struct sockaddr_in6 *sin6; 628 629 if ((rt = inp->in6p_route.ro_rt) == NULL) 630 goto no_valid_rt; 631 sin6 = (struct sockaddr_in6 *)rt_key(rt); 632 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 633 goto no_valid_rt; 634 } 635 else 636 #endif /* INET6 */ 637 if ((rt = inp->inp_route.ro_rt) == NULL || 638 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr 639 == INADDR_ANY) 640 goto no_valid_rt; 641 642 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 643 i = tp->t_srtt * 644 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 645 if (rt->rt_rmx.rmx_rtt && i) 646 /* 647 * filter this update to half the old & half 648 * the new values, converting scale. 649 * See route.h and tcp_var.h for a 650 * description of the scaling constants. 651 */ 652 rt->rt_rmx.rmx_rtt = 653 (rt->rt_rmx.rmx_rtt + i) / 2; 654 else 655 rt->rt_rmx.rmx_rtt = i; 656 tcpstat.tcps_cachedrtt++; 657 } 658 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 659 i = tp->t_rttvar * 660 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 661 if (rt->rt_rmx.rmx_rttvar && i) 662 rt->rt_rmx.rmx_rttvar = 663 (rt->rt_rmx.rmx_rttvar + i) / 2; 664 else 665 rt->rt_rmx.rmx_rttvar = i; 666 tcpstat.tcps_cachedrttvar++; 667 } 668 /* 669 * The old comment here said: 670 * update the pipelimit (ssthresh) if it has been updated 671 * already or if a pipesize was specified & the threshhold 672 * got below half the pipesize. I.e., wait for bad news 673 * before we start updating, then update on both good 674 * and bad news. 675 * 676 * But we want to save the ssthresh even if no pipesize is 677 * specified explicitly in the route, because such 678 * connections still have an implicit pipesize specified 679 * by the global tcp_sendspace. In the absence of a reliable 680 * way to calculate the pipesize, it will have to do. 681 */ 682 i = tp->snd_ssthresh; 683 if (rt->rt_rmx.rmx_sendpipe != 0) 684 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2); 685 else 686 dosavessthresh = (i < so->so_snd.sb_hiwat / 2); 687 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 688 i != 0 && rt->rt_rmx.rmx_ssthresh != 0) 689 || dosavessthresh) { 690 /* 691 * convert the limit from user data bytes to 692 * packets then to packet data bytes. 693 */ 694 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 695 if (i < 2) 696 i = 2; 697 i *= (u_long)(tp->t_maxseg + 698 #ifdef INET6 699 (isipv6 ? sizeof (struct ip6_hdr) + 700 sizeof (struct tcphdr) : 701 #endif 702 sizeof (struct tcpiphdr) 703 #ifdef INET6 704 ) 705 #endif 706 ); 707 if (rt->rt_rmx.rmx_ssthresh) 708 rt->rt_rmx.rmx_ssthresh = 709 (rt->rt_rmx.rmx_ssthresh + i) / 2; 710 else 711 rt->rt_rmx.rmx_ssthresh = i; 712 tcpstat.tcps_cachedssthresh++; 713 } 714 } 715 no_valid_rt: 716 /* free the reassembly queue, if any */ 717 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 718 LIST_REMOVE(q, tqe_q); 719 m_freem(q->tqe_m); 720 FREE(q, M_TSEGQ); 721 } 722 inp->inp_ppcb = NULL; 723 soisdisconnected(so); 724 #ifdef INET6 725 if (INP_CHECK_SOCKAF(so, AF_INET6)) 726 in6_pcbdetach(inp); 727 else 728 #endif /* INET6 */ 729 in_pcbdetach(inp); 730 tcpstat.tcps_closed++; 731 return ((struct tcpcb *)0); 732 } 733 734 void 735 tcp_drain() 736 { 737 if (do_tcpdrain) 738 { 739 struct inpcb *inpb; 740 struct tcpcb *tcpb; 741 struct tseg_qent *te; 742 743 /* 744 * Walk the tcpbs, if existing, and flush the reassembly queue, 745 * if there is one... 746 * XXX: The "Net/3" implementation doesn't imply that the TCP 747 * reassembly queue should be flushed, but in a situation 748 * where we're really low on mbufs, this is potentially 749 * usefull. 750 */ 751 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) { 752 if ((tcpb = intotcpcb(inpb))) { 753 while ((te = LIST_FIRST(&tcpb->t_segq)) 754 != NULL) { 755 LIST_REMOVE(te, tqe_q); 756 m_freem(te->tqe_m); 757 FREE(te, M_TSEGQ); 758 } 759 } 760 } 761 } 762 } 763 764 /* 765 * Notify a tcp user of an asynchronous error; 766 * store error as soft error, but wake up user 767 * (for now, won't do anything until can select for soft error). 768 * 769 * Do not wake up user since there currently is no mechanism for 770 * reporting soft errors (yet - a kqueue filter may be added). 771 */ 772 static void 773 tcp_notify(inp, error) 774 struct inpcb *inp; 775 int error; 776 { 777 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 778 779 /* 780 * Ignore some errors if we are hooked up. 781 * If connection hasn't completed, has retransmitted several times, 782 * and receives a second error, give up now. This is better 783 * than waiting a long time to establish a connection that 784 * can never complete. 785 */ 786 if (tp->t_state == TCPS_ESTABLISHED && 787 (error == EHOSTUNREACH || error == ENETUNREACH || 788 error == EHOSTDOWN)) { 789 return; 790 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 791 tp->t_softerror) 792 tcp_drop(tp, error); 793 else 794 tp->t_softerror = error; 795 #if 0 796 wakeup((caddr_t) &so->so_timeo); 797 sorwakeup(so); 798 sowwakeup(so); 799 #endif 800 } 801 802 static int 803 tcp_pcblist(SYSCTL_HANDLER_ARGS) 804 { 805 int error, i, n, s; 806 struct inpcb *inp, **inp_list; 807 inp_gen_t gencnt; 808 struct xinpgen xig; 809 810 /* 811 * The process of preparing the TCB list is too time-consuming and 812 * resource-intensive to repeat twice on every request. 813 */ 814 if (req->oldptr == 0) { 815 n = tcbinfo.ipi_count; 816 req->oldidx = 2 * (sizeof xig) 817 + (n + n/8) * sizeof(struct xtcpcb); 818 return 0; 819 } 820 821 if (req->newptr != 0) 822 return EPERM; 823 824 /* 825 * OK, now we're committed to doing something. 826 */ 827 s = splnet(); 828 gencnt = tcbinfo.ipi_gencnt; 829 n = tcbinfo.ipi_count; 830 splx(s); 831 832 xig.xig_len = sizeof xig; 833 xig.xig_count = n; 834 xig.xig_gen = gencnt; 835 xig.xig_sogen = so_gencnt; 836 error = SYSCTL_OUT(req, &xig, sizeof xig); 837 if (error) 838 return error; 839 840 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 841 if (inp_list == 0) 842 return ENOMEM; 843 844 s = splnet(); 845 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n; 846 inp = LIST_NEXT(inp, inp_list)) { 847 if (inp->inp_gencnt <= gencnt) { 848 if (cr_cansee(req->td->td_proc->p_ucred, 849 inp->inp_socket->so_cred)) 850 continue; 851 inp_list[i++] = inp; 852 } 853 } 854 splx(s); 855 n = i; 856 857 error = 0; 858 for (i = 0; i < n; i++) { 859 inp = inp_list[i]; 860 if (inp->inp_gencnt <= gencnt) { 861 struct xtcpcb xt; 862 caddr_t inp_ppcb; 863 xt.xt_len = sizeof xt; 864 /* XXX should avoid extra copy */ 865 bcopy(inp, &xt.xt_inp, sizeof *inp); 866 inp_ppcb = inp->inp_ppcb; 867 if (inp_ppcb != NULL) 868 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 869 else 870 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 871 if (inp->inp_socket) 872 sotoxsocket(inp->inp_socket, &xt.xt_socket); 873 error = SYSCTL_OUT(req, &xt, sizeof xt); 874 } 875 } 876 if (!error) { 877 /* 878 * Give the user an updated idea of our state. 879 * If the generation differs from what we told 880 * her before, she knows that something happened 881 * while we were processing this request, and it 882 * might be necessary to retry. 883 */ 884 s = splnet(); 885 xig.xig_gen = tcbinfo.ipi_gencnt; 886 xig.xig_sogen = so_gencnt; 887 xig.xig_count = tcbinfo.ipi_count; 888 splx(s); 889 error = SYSCTL_OUT(req, &xig, sizeof xig); 890 } 891 free(inp_list, M_TEMP); 892 return error; 893 } 894 895 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 896 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 897 898 static int 899 tcp_getcred(SYSCTL_HANDLER_ARGS) 900 { 901 struct xucred xuc; 902 struct sockaddr_in addrs[2]; 903 struct inpcb *inp; 904 int error, s; 905 906 error = suser_xxx(0, req->td->td_proc, PRISON_ROOT); 907 if (error) 908 return (error); 909 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 910 if (error) 911 return (error); 912 s = splnet(); 913 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 914 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 915 if (inp == NULL || inp->inp_socket == NULL) { 916 error = ENOENT; 917 goto out; 918 } 919 error = cr_cansee(req->td->td_proc->p_ucred, inp->inp_socket->so_cred); 920 if (error) 921 goto out; 922 bzero(&xuc, sizeof(xuc)); 923 xuc.cr_uid = inp->inp_socket->so_cred->cr_uid; 924 xuc.cr_ngroups = inp->inp_socket->so_cred->cr_ngroups; 925 bcopy(inp->inp_socket->so_cred->cr_groups, xuc.cr_groups, 926 sizeof(xuc.cr_groups)); 927 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 928 out: 929 splx(s); 930 return (error); 931 } 932 933 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 934 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 935 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 936 937 #ifdef INET6 938 static int 939 tcp6_getcred(SYSCTL_HANDLER_ARGS) 940 { 941 struct xucred xuc; 942 struct sockaddr_in6 addrs[2]; 943 struct inpcb *inp; 944 int error, s, mapped = 0; 945 946 error = suser_xxx(0, req->td->td_proc, PRISON_ROOT); 947 if (error) 948 return (error); 949 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 950 if (error) 951 return (error); 952 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 953 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 954 mapped = 1; 955 else 956 return (EINVAL); 957 } 958 s = splnet(); 959 if (mapped == 1) 960 inp = in_pcblookup_hash(&tcbinfo, 961 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 962 addrs[1].sin6_port, 963 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 964 addrs[0].sin6_port, 965 0, NULL); 966 else 967 inp = in6_pcblookup_hash(&tcbinfo, &addrs[1].sin6_addr, 968 addrs[1].sin6_port, 969 &addrs[0].sin6_addr, addrs[0].sin6_port, 970 0, NULL); 971 if (inp == NULL || inp->inp_socket == NULL) { 972 error = ENOENT; 973 goto out; 974 } 975 error = cr_cansee(req->td->td_proc->p_ucred, inp->inp_socket->so_cred); 976 if (error) 977 goto out; 978 bzero(&xuc, sizeof(xuc)); 979 xuc.cr_uid = inp->inp_socket->so_cred->cr_uid; 980 xuc.cr_ngroups = inp->inp_socket->so_cred->cr_ngroups; 981 bcopy(inp->inp_socket->so_cred->cr_groups, xuc.cr_groups, 982 sizeof(xuc.cr_groups)); 983 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 984 out: 985 splx(s); 986 return (error); 987 } 988 989 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 990 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 991 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 992 #endif 993 994 995 void 996 tcp_ctlinput(cmd, sa, vip) 997 int cmd; 998 struct sockaddr *sa; 999 void *vip; 1000 { 1001 struct ip *ip = vip; 1002 struct tcphdr *th; 1003 struct in_addr faddr; 1004 struct inpcb *inp; 1005 struct tcpcb *tp; 1006 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1007 tcp_seq icmp_seq; 1008 int s; 1009 1010 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1011 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1012 return; 1013 1014 if (cmd == PRC_QUENCH) 1015 notify = tcp_quench; 1016 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1017 cmd == PRC_UNREACH_PORT) && ip) 1018 notify = tcp_drop_syn_sent; 1019 else if (cmd == PRC_MSGSIZE) 1020 notify = tcp_mtudisc; 1021 else if (PRC_IS_REDIRECT(cmd)) { 1022 ip = 0; 1023 notify = in_rtchange; 1024 } else if (cmd == PRC_HOSTDEAD) 1025 ip = 0; 1026 else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0) 1027 return; 1028 if (ip) { 1029 s = splnet(); 1030 th = (struct tcphdr *)((caddr_t)ip 1031 + (IP_VHL_HL(ip->ip_vhl) << 2)); 1032 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1033 ip->ip_src, th->th_sport, 0, NULL); 1034 if (inp != NULL && inp->inp_socket != NULL) { 1035 icmp_seq = htonl(th->th_seq); 1036 tp = intotcpcb(inp); 1037 if (SEQ_GEQ(icmp_seq, tp->snd_una) && 1038 SEQ_LT(icmp_seq, tp->snd_max)) 1039 (*notify)(inp, inetctlerrmap[cmd]); 1040 } else { 1041 struct in_conninfo inc; 1042 1043 inc.inc_fport = th->th_dport; 1044 inc.inc_lport = th->th_sport; 1045 inc.inc_faddr = faddr; 1046 inc.inc_laddr = ip->ip_src; 1047 #ifdef INET6 1048 inc.inc_isipv6 = 0; 1049 #endif 1050 syncache_unreach(&inc, th); 1051 } 1052 splx(s); 1053 } else 1054 in_pcbnotifyall(&tcb, faddr, inetctlerrmap[cmd], notify); 1055 } 1056 1057 #ifdef INET6 1058 void 1059 tcp6_ctlinput(cmd, sa, d) 1060 int cmd; 1061 struct sockaddr *sa; 1062 void *d; 1063 { 1064 struct tcphdr th; 1065 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1066 struct ip6_hdr *ip6; 1067 struct mbuf *m; 1068 struct ip6ctlparam *ip6cp = NULL; 1069 const struct sockaddr_in6 *sa6_src = NULL; 1070 int off; 1071 struct tcp_portonly { 1072 u_int16_t th_sport; 1073 u_int16_t th_dport; 1074 } *thp; 1075 1076 if (sa->sa_family != AF_INET6 || 1077 sa->sa_len != sizeof(struct sockaddr_in6)) 1078 return; 1079 1080 if (cmd == PRC_QUENCH) 1081 notify = tcp_quench; 1082 else if (cmd == PRC_MSGSIZE) 1083 notify = tcp_mtudisc; 1084 else if (!PRC_IS_REDIRECT(cmd) && 1085 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1086 return; 1087 1088 /* if the parameter is from icmp6, decode it. */ 1089 if (d != NULL) { 1090 ip6cp = (struct ip6ctlparam *)d; 1091 m = ip6cp->ip6c_m; 1092 ip6 = ip6cp->ip6c_ip6; 1093 off = ip6cp->ip6c_off; 1094 sa6_src = ip6cp->ip6c_src; 1095 } else { 1096 m = NULL; 1097 ip6 = NULL; 1098 off = 0; /* fool gcc */ 1099 sa6_src = &sa6_any; 1100 } 1101 1102 if (ip6) { 1103 struct in_conninfo inc; 1104 /* 1105 * XXX: We assume that when IPV6 is non NULL, 1106 * M and OFF are valid. 1107 */ 1108 1109 /* check if we can safely examine src and dst ports */ 1110 if (m->m_pkthdr.len < off + sizeof(*thp)) 1111 return; 1112 1113 bzero(&th, sizeof(th)); 1114 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1115 1116 in6_pcbnotify(&tcb, sa, th.th_dport, 1117 (struct sockaddr *)ip6cp->ip6c_src, 1118 th.th_sport, cmd, notify); 1119 1120 inc.inc_fport = th.th_dport; 1121 inc.inc_lport = th.th_sport; 1122 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1123 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1124 inc.inc_isipv6 = 1; 1125 syncache_unreach(&inc, &th); 1126 } else 1127 in6_pcbnotify(&tcb, sa, 0, (struct sockaddr *)sa6_src, 1128 0, cmd, notify); 1129 } 1130 #endif /* INET6 */ 1131 1132 1133 /* 1134 * Following is where TCP initial sequence number generation occurs. 1135 * 1136 * There are two places where we must use initial sequence numbers: 1137 * 1. In SYN-ACK packets. 1138 * 2. In SYN packets. 1139 * 1140 * The ISNs in SYN-ACK packets have no monotonicity requirement, 1141 * and should be as unpredictable as possible to avoid the possibility 1142 * of spoofing and/or connection hijacking. To satisfy this 1143 * requirement, SYN-ACK ISNs are generated via the arc4random() 1144 * function. If exact RFC 1948 compliance is requested via sysctl, 1145 * these ISNs will be generated just like those in SYN packets. 1146 * 1147 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1148 * depends on this property. In addition, these ISNs should be 1149 * unguessable so as to prevent connection hijacking. To satisfy 1150 * the requirements of this situation, the algorithm outlined in 1151 * RFC 1948 is used to generate sequence numbers. 1152 * 1153 * For more information on the theory of operation, please see 1154 * RFC 1948. 1155 * 1156 * Implementation details: 1157 * 1158 * Time is based off the system timer, and is corrected so that it 1159 * increases by one megabyte per second. This allows for proper 1160 * recycling on high speed LANs while still leaving over an hour 1161 * before rollover. 1162 * 1163 * Two sysctls control the generation of ISNs: 1164 * 1165 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1166 * between seeding of isn_secret. This is normally set to zero, 1167 * as reseeding should not be necessary. 1168 * 1169 * net.inet.tcp.strict_rfc1948 controls whether RFC 1948 is followed 1170 * strictly. When strict compliance is requested, reseeding is 1171 * disabled and SYN-ACKs will be generated in the same manner as 1172 * SYNs. Strict mode is disabled by default. 1173 * 1174 */ 1175 1176 #define ISN_BYTES_PER_SECOND 1048576 1177 1178 u_char isn_secret[32]; 1179 int isn_last_reseed; 1180 MD5_CTX isn_ctx; 1181 1182 tcp_seq 1183 tcp_new_isn(tp) 1184 struct tcpcb *tp; 1185 { 1186 u_int32_t md5_buffer[4]; 1187 tcp_seq new_isn; 1188 1189 /* Use arc4random for SYN-ACKs when not in exact RFC1948 mode. */ 1190 if (((tp->t_state == TCPS_LISTEN) || (tp->t_state == TCPS_TIME_WAIT)) 1191 && tcp_strict_rfc1948 == 0) 1192 return arc4random(); 1193 1194 /* Seed if this is the first use, reseed if requested. */ 1195 if ((isn_last_reseed == 0) || 1196 ((tcp_strict_rfc1948 == 0) && (tcp_isn_reseed_interval > 0) && 1197 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1198 < (u_int)ticks))) { 1199 read_random(&isn_secret, sizeof(isn_secret)); 1200 isn_last_reseed = ticks; 1201 } 1202 1203 /* Compute the md5 hash and return the ISN. */ 1204 MD5Init(&isn_ctx); 1205 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1206 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1207 #ifdef INET6 1208 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1209 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1210 sizeof(struct in6_addr)); 1211 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1212 sizeof(struct in6_addr)); 1213 } else 1214 #endif 1215 { 1216 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1217 sizeof(struct in_addr)); 1218 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1219 sizeof(struct in_addr)); 1220 } 1221 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1222 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1223 new_isn = (tcp_seq) md5_buffer[0]; 1224 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1225 return new_isn; 1226 } 1227 1228 /* 1229 * When a source quench is received, close congestion window 1230 * to one segment. We will gradually open it again as we proceed. 1231 */ 1232 void 1233 tcp_quench(inp, errno) 1234 struct inpcb *inp; 1235 int errno; 1236 { 1237 struct tcpcb *tp = intotcpcb(inp); 1238 1239 if (tp) 1240 tp->snd_cwnd = tp->t_maxseg; 1241 } 1242 1243 /* 1244 * When a specific ICMP unreachable message is received and the 1245 * connection state is SYN-SENT, drop the connection. This behavior 1246 * is controlled by the icmp_may_rst sysctl. 1247 */ 1248 void 1249 tcp_drop_syn_sent(inp, errno) 1250 struct inpcb *inp; 1251 int errno; 1252 { 1253 struct tcpcb *tp = intotcpcb(inp); 1254 1255 if (tp && tp->t_state == TCPS_SYN_SENT) 1256 tcp_drop(tp, errno); 1257 } 1258 1259 /* 1260 * When `need fragmentation' ICMP is received, update our idea of the MSS 1261 * based on the new value in the route. Also nudge TCP to send something, 1262 * since we know the packet we just sent was dropped. 1263 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1264 */ 1265 void 1266 tcp_mtudisc(inp, errno) 1267 struct inpcb *inp; 1268 int errno; 1269 { 1270 struct tcpcb *tp = intotcpcb(inp); 1271 struct rtentry *rt; 1272 struct rmxp_tao *taop; 1273 struct socket *so = inp->inp_socket; 1274 int offered; 1275 int mss; 1276 #ifdef INET6 1277 int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1278 #endif /* INET6 */ 1279 1280 if (tp) { 1281 #ifdef INET6 1282 if (isipv6) 1283 rt = tcp_rtlookup6(&inp->inp_inc); 1284 else 1285 #endif /* INET6 */ 1286 rt = tcp_rtlookup(&inp->inp_inc); 1287 if (!rt || !rt->rt_rmx.rmx_mtu) { 1288 tp->t_maxopd = tp->t_maxseg = 1289 #ifdef INET6 1290 isipv6 ? tcp_v6mssdflt : 1291 #endif /* INET6 */ 1292 tcp_mssdflt; 1293 return; 1294 } 1295 taop = rmx_taop(rt->rt_rmx); 1296 offered = taop->tao_mssopt; 1297 mss = rt->rt_rmx.rmx_mtu - 1298 #ifdef INET6 1299 (isipv6 ? 1300 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1301 #endif /* INET6 */ 1302 sizeof(struct tcpiphdr) 1303 #ifdef INET6 1304 ) 1305 #endif /* INET6 */ 1306 ; 1307 1308 if (offered) 1309 mss = min(mss, offered); 1310 /* 1311 * XXX - The above conditional probably violates the TCP 1312 * spec. The problem is that, since we don't know the 1313 * other end's MSS, we are supposed to use a conservative 1314 * default. But, if we do that, then MTU discovery will 1315 * never actually take place, because the conservative 1316 * default is much less than the MTUs typically seen 1317 * on the Internet today. For the moment, we'll sweep 1318 * this under the carpet. 1319 * 1320 * The conservative default might not actually be a problem 1321 * if the only case this occurs is when sending an initial 1322 * SYN with options and data to a host we've never talked 1323 * to before. Then, they will reply with an MSS value which 1324 * will get recorded and the new parameters should get 1325 * recomputed. For Further Study. 1326 */ 1327 if (tp->t_maxopd <= mss) 1328 return; 1329 tp->t_maxopd = mss; 1330 1331 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1332 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1333 mss -= TCPOLEN_TSTAMP_APPA; 1334 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC && 1335 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC) 1336 mss -= TCPOLEN_CC_APPA; 1337 #if (MCLBYTES & (MCLBYTES - 1)) == 0 1338 if (mss > MCLBYTES) 1339 mss &= ~(MCLBYTES-1); 1340 #else 1341 if (mss > MCLBYTES) 1342 mss = mss / MCLBYTES * MCLBYTES; 1343 #endif 1344 if (so->so_snd.sb_hiwat < mss) 1345 mss = so->so_snd.sb_hiwat; 1346 1347 tp->t_maxseg = mss; 1348 1349 tcpstat.tcps_mturesent++; 1350 tp->t_rtttime = 0; 1351 tp->snd_nxt = tp->snd_una; 1352 tcp_output(tp); 1353 } 1354 } 1355 1356 /* 1357 * Look-up the routing entry to the peer of this inpcb. If no route 1358 * is found and it cannot be allocated the return NULL. This routine 1359 * is called by TCP routines that access the rmx structure and by tcp_mss 1360 * to get the interface MTU. 1361 */ 1362 struct rtentry * 1363 tcp_rtlookup(inc) 1364 struct in_conninfo *inc; 1365 { 1366 struct route *ro; 1367 struct rtentry *rt; 1368 1369 ro = &inc->inc_route; 1370 rt = ro->ro_rt; 1371 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1372 /* No route yet, so try to acquire one */ 1373 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1374 ro->ro_dst.sa_family = AF_INET; 1375 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1376 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1377 inc->inc_faddr; 1378 rtalloc(ro); 1379 rt = ro->ro_rt; 1380 } 1381 } 1382 return rt; 1383 } 1384 1385 #ifdef INET6 1386 struct rtentry * 1387 tcp_rtlookup6(inc) 1388 struct in_conninfo *inc; 1389 { 1390 struct route_in6 *ro6; 1391 struct rtentry *rt; 1392 1393 ro6 = &inc->inc6_route; 1394 rt = ro6->ro_rt; 1395 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1396 /* No route yet, so try to acquire one */ 1397 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1398 ro6->ro_dst.sin6_family = AF_INET6; 1399 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1400 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1401 rtalloc((struct route *)ro6); 1402 rt = ro6->ro_rt; 1403 } 1404 } 1405 return rt; 1406 } 1407 #endif /* INET6 */ 1408 1409 #ifdef IPSEC 1410 /* compute ESP/AH header size for TCP, including outer IP header. */ 1411 size_t 1412 ipsec_hdrsiz_tcp(tp) 1413 struct tcpcb *tp; 1414 { 1415 struct inpcb *inp; 1416 struct mbuf *m; 1417 size_t hdrsiz; 1418 struct ip *ip; 1419 #ifdef INET6 1420 struct ip6_hdr *ip6; 1421 #endif /* INET6 */ 1422 struct tcphdr *th; 1423 1424 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1425 return 0; 1426 MGETHDR(m, M_DONTWAIT, MT_DATA); 1427 if (!m) 1428 return 0; 1429 1430 #ifdef INET6 1431 if ((inp->inp_vflag & INP_IPV6) != 0) { 1432 ip6 = mtod(m, struct ip6_hdr *); 1433 th = (struct tcphdr *)(ip6 + 1); 1434 m->m_pkthdr.len = m->m_len = 1435 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1436 tcp_fillheaders(tp, ip6, th); 1437 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1438 } else 1439 #endif /* INET6 */ 1440 { 1441 ip = mtod(m, struct ip *); 1442 th = (struct tcphdr *)(ip + 1); 1443 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1444 tcp_fillheaders(tp, ip, th); 1445 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1446 } 1447 1448 m_free(m); 1449 return hdrsiz; 1450 } 1451 #endif /*IPSEC*/ 1452 1453 /* 1454 * Return a pointer to the cached information about the remote host. 1455 * The cached information is stored in the protocol specific part of 1456 * the route metrics. 1457 */ 1458 struct rmxp_tao * 1459 tcp_gettaocache(inc) 1460 struct in_conninfo *inc; 1461 { 1462 struct rtentry *rt; 1463 1464 #ifdef INET6 1465 if (inc->inc_isipv6) 1466 rt = tcp_rtlookup6(inc); 1467 else 1468 #endif /* INET6 */ 1469 rt = tcp_rtlookup(inc); 1470 1471 /* Make sure this is a host route and is up. */ 1472 if (rt == NULL || 1473 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)) 1474 return NULL; 1475 1476 return rmx_taop(rt->rt_rmx); 1477 } 1478 1479 /* 1480 * Clear all the TAO cache entries, called from tcp_init. 1481 * 1482 * XXX 1483 * This routine is just an empty one, because we assume that the routing 1484 * routing tables are initialized at the same time when TCP, so there is 1485 * nothing in the cache left over. 1486 */ 1487 static void 1488 tcp_cleartaocache() 1489 { 1490 } 1491