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> 101 102 int tcp_mssdflt = TCP_MSS; 103 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 104 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size"); 105 106 #ifdef INET6 107 int tcp_v6mssdflt = TCP6_MSS; 108 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 109 CTLFLAG_RW, &tcp_v6mssdflt , 0, 110 "Default TCP Maximum Segment Size for IPv6"); 111 #endif 112 113 #if 0 114 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 115 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 116 &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time"); 117 #endif 118 119 static int tcp_do_rfc1323 = 1; 120 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 121 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions"); 122 123 static int tcp_do_rfc1644 = 0; 124 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 125 &tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions"); 126 127 static int tcp_tcbhashsize = 0; 128 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 129 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 130 131 static int do_tcpdrain = 1; 132 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 133 "Enable tcp_drain routine for extra help when low on mbufs"); 134 135 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 136 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 137 138 static int icmp_may_rst = 1; 139 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 140 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 141 142 static void tcp_cleartaocache __P((void)); 143 static void tcp_notify __P((struct inpcb *, int)); 144 145 /* 146 * Target size of TCP PCB hash tables. Must be a power of two. 147 * 148 * Note that this can be overridden by the kernel environment 149 * variable net.inet.tcp.tcbhashsize 150 */ 151 #ifndef TCBHASHSIZE 152 #define TCBHASHSIZE 512 153 #endif 154 155 /* 156 * This is the actual shape of what we allocate using the zone 157 * allocator. Doing it this way allows us to protect both structures 158 * using the same generation count, and also eliminates the overhead 159 * of allocating tcpcbs separately. By hiding the structure here, 160 * we avoid changing most of the rest of the code (although it needs 161 * to be changed, eventually, for greater efficiency). 162 */ 163 #define ALIGNMENT 32 164 #define ALIGNM1 (ALIGNMENT - 1) 165 struct inp_tp { 166 union { 167 struct inpcb inp; 168 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 169 } inp_tp_u; 170 struct tcpcb tcb; 171 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl; 172 struct callout inp_tp_delack; 173 }; 174 #undef ALIGNMENT 175 #undef ALIGNM1 176 177 /* 178 * Tcp initialization 179 */ 180 void 181 tcp_init() 182 { 183 int hashsize; 184 185 tcp_ccgen = 1; 186 tcp_cleartaocache(); 187 188 tcp_delacktime = TCPTV_DELACK; 189 tcp_keepinit = TCPTV_KEEP_INIT; 190 tcp_keepidle = TCPTV_KEEP_IDLE; 191 tcp_keepintvl = TCPTV_KEEPINTVL; 192 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 193 tcp_msl = TCPTV_MSL; 194 195 LIST_INIT(&tcb); 196 tcbinfo.listhead = &tcb; 197 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", TCBHASHSIZE, hashsize); 198 if (!powerof2(hashsize)) { 199 printf("WARNING: TCB hash size not a power of 2\n"); 200 hashsize = 512; /* safe default */ 201 } 202 tcp_tcbhashsize = hashsize; 203 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask); 204 tcbinfo.porthashbase = hashinit(hashsize, M_PCB, 205 &tcbinfo.porthashmask); 206 tcbinfo.ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 207 ZONE_INTERRUPT, 0); 208 #ifdef INET6 209 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 210 #else /* INET6 */ 211 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 212 #endif /* INET6 */ 213 if (max_protohdr < TCP_MINPROTOHDR) 214 max_protohdr = TCP_MINPROTOHDR; 215 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 216 panic("tcp_init"); 217 #undef TCP_MINPROTOHDR 218 } 219 220 /* 221 * Create template to be used to send tcp packets on a connection. 222 * Call after host entry created, allocates an mbuf and fills 223 * in a skeletal tcp/ip header, minimizing the amount of work 224 * necessary when the connection is used. 225 */ 226 struct tcptemp * 227 tcp_template(tp) 228 struct tcpcb *tp; 229 { 230 register struct inpcb *inp = tp->t_inpcb; 231 register struct mbuf *m; 232 register struct tcptemp *n; 233 234 if ((n = tp->t_template) == 0) { 235 m = m_get(M_DONTWAIT, MT_HEADER); 236 if (m == NULL) 237 return (0); 238 m->m_len = sizeof (struct tcptemp); 239 n = mtod(m, struct tcptemp *); 240 } 241 #ifdef INET6 242 if ((inp->inp_vflag & INP_IPV6) != 0) { 243 register struct ip6_hdr *ip6; 244 245 ip6 = (struct ip6_hdr *)n->tt_ipgen; 246 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 247 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 248 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 249 (IPV6_VERSION & IPV6_VERSION_MASK); 250 ip6->ip6_nxt = IPPROTO_TCP; 251 ip6->ip6_plen = sizeof(struct tcphdr); 252 ip6->ip6_src = inp->in6p_laddr; 253 ip6->ip6_dst = inp->in6p_faddr; 254 n->tt_t.th_sum = 0; 255 } else 256 #endif 257 { 258 struct ip *ip = (struct ip *)n->tt_ipgen; 259 260 bzero(ip, sizeof(struct ip)); /* XXX overkill? */ 261 ip->ip_vhl = IP_VHL_BORING; 262 ip->ip_p = IPPROTO_TCP; 263 ip->ip_src = inp->inp_laddr; 264 ip->ip_dst = inp->inp_faddr; 265 n->tt_t.th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 266 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 267 } 268 n->tt_t.th_sport = inp->inp_lport; 269 n->tt_t.th_dport = inp->inp_fport; 270 n->tt_t.th_seq = 0; 271 n->tt_t.th_ack = 0; 272 n->tt_t.th_x2 = 0; 273 n->tt_t.th_off = 5; 274 n->tt_t.th_flags = 0; 275 n->tt_t.th_win = 0; 276 n->tt_t.th_urp = 0; 277 return (n); 278 } 279 280 /* 281 * Send a single message to the TCP at address specified by 282 * the given TCP/IP header. If m == 0, then we make a copy 283 * of the tcpiphdr at ti and send directly to the addressed host. 284 * This is used to force keep alive messages out using the TCP 285 * template for a connection tp->t_template. If flags are given 286 * then we send a message back to the TCP which originated the 287 * segment ti, and discard the mbuf containing it and any other 288 * attached mbufs. 289 * 290 * In any case the ack and sequence number of the transmitted 291 * segment are as specified by the parameters. 292 * 293 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 294 */ 295 void 296 tcp_respond(tp, ipgen, th, m, ack, seq, flags) 297 struct tcpcb *tp; 298 void *ipgen; 299 register struct tcphdr *th; 300 register struct mbuf *m; 301 tcp_seq ack, seq; 302 int flags; 303 { 304 register int tlen; 305 int win = 0; 306 struct route *ro = 0; 307 struct route sro; 308 struct ip *ip; 309 struct tcphdr *nth; 310 #ifdef INET6 311 struct route_in6 *ro6 = 0; 312 struct route_in6 sro6; 313 struct ip6_hdr *ip6; 314 int isipv6; 315 #endif /* INET6 */ 316 int ipflags = 0; 317 318 #ifdef INET6 319 isipv6 = IP_VHL_V(((struct ip *)ipgen)->ip_vhl) == 6; 320 ip6 = ipgen; 321 #endif /* INET6 */ 322 ip = ipgen; 323 324 if (tp) { 325 if (!(flags & TH_RST)) { 326 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 327 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 328 win = (long)TCP_MAXWIN << tp->rcv_scale; 329 } 330 #ifdef INET6 331 if (isipv6) 332 ro6 = &tp->t_inpcb->in6p_route; 333 else 334 #endif /* INET6 */ 335 ro = &tp->t_inpcb->inp_route; 336 } else { 337 #ifdef INET6 338 if (isipv6) { 339 ro6 = &sro6; 340 bzero(ro6, sizeof *ro6); 341 } else 342 #endif /* INET6 */ 343 { 344 ro = &sro; 345 bzero(ro, sizeof *ro); 346 } 347 } 348 if (m == 0) { 349 m = m_gethdr(M_DONTWAIT, MT_HEADER); 350 if (m == NULL) 351 return; 352 tlen = 0; 353 m->m_data += max_linkhdr; 354 #ifdef INET6 355 if (isipv6) { 356 bcopy((caddr_t)ip6, mtod(m, caddr_t), 357 sizeof(struct ip6_hdr)); 358 ip6 = mtod(m, struct ip6_hdr *); 359 nth = (struct tcphdr *)(ip6 + 1); 360 } else 361 #endif /* INET6 */ 362 { 363 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 364 ip = mtod(m, struct ip *); 365 nth = (struct tcphdr *)(ip + 1); 366 } 367 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 368 flags = TH_ACK; 369 } else { 370 m_freem(m->m_next); 371 m->m_next = 0; 372 m->m_data = (caddr_t)ipgen; 373 /* m_len is set later */ 374 tlen = 0; 375 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 376 #ifdef INET6 377 if (isipv6) { 378 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 379 nth = (struct tcphdr *)(ip6 + 1); 380 } else 381 #endif /* INET6 */ 382 { 383 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 384 nth = (struct tcphdr *)(ip + 1); 385 } 386 if (th != nth) { 387 /* 388 * this is usually a case when an extension header 389 * exists between the IPv6 header and the 390 * TCP header. 391 */ 392 nth->th_sport = th->th_sport; 393 nth->th_dport = th->th_dport; 394 } 395 xchg(nth->th_dport, nth->th_sport, n_short); 396 #undef xchg 397 } 398 #ifdef INET6 399 if (isipv6) { 400 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 401 tlen)); 402 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 403 } else 404 #endif 405 { 406 tlen += sizeof (struct tcpiphdr); 407 ip->ip_len = tlen; 408 ip->ip_ttl = ip_defttl; 409 } 410 m->m_len = tlen; 411 m->m_pkthdr.len = tlen; 412 m->m_pkthdr.rcvif = (struct ifnet *) 0; 413 nth->th_seq = htonl(seq); 414 nth->th_ack = htonl(ack); 415 nth->th_x2 = 0; 416 nth->th_off = sizeof (struct tcphdr) >> 2; 417 nth->th_flags = flags; 418 if (tp) 419 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 420 else 421 nth->th_win = htons((u_short)win); 422 nth->th_urp = 0; 423 #ifdef INET6 424 if (isipv6) { 425 nth->th_sum = 0; 426 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 427 sizeof(struct ip6_hdr), 428 tlen - sizeof(struct ip6_hdr)); 429 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 430 ro6 && ro6->ro_rt ? 431 ro6->ro_rt->rt_ifp : 432 NULL); 433 } else 434 #endif /* INET6 */ 435 { 436 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 437 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 438 m->m_pkthdr.csum_flags = CSUM_TCP; 439 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 440 } 441 #ifdef TCPDEBUG 442 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 443 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 444 #endif 445 #ifdef IPSEC 446 ipsec_setsocket(m, tp ? tp->t_inpcb->inp_socket : NULL); 447 #endif 448 #ifdef INET6 449 if (isipv6) { 450 (void)ip6_output(m, NULL, ro6, ipflags, NULL, NULL); 451 if (ro6 == &sro6 && ro6->ro_rt) { 452 RTFREE(ro6->ro_rt); 453 ro6->ro_rt = NULL; 454 } 455 } else 456 #endif /* INET6 */ 457 { 458 (void) ip_output(m, NULL, ro, ipflags, NULL); 459 if (ro == &sro && ro->ro_rt) { 460 RTFREE(ro->ro_rt); 461 ro->ro_rt = NULL; 462 } 463 } 464 } 465 466 /* 467 * Create a new TCP control block, making an 468 * empty reassembly queue and hooking it to the argument 469 * protocol control block. The `inp' parameter must have 470 * come from the zone allocator set up in tcp_init(). 471 */ 472 struct tcpcb * 473 tcp_newtcpcb(inp) 474 struct inpcb *inp; 475 { 476 struct inp_tp *it; 477 register struct tcpcb *tp; 478 #ifdef INET6 479 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 480 #endif /* INET6 */ 481 482 it = (struct inp_tp *)inp; 483 tp = &it->tcb; 484 bzero((char *) tp, sizeof(struct tcpcb)); 485 LIST_INIT(&tp->t_segq); 486 tp->t_maxseg = tp->t_maxopd = 487 #ifdef INET6 488 isipv6 ? tcp_v6mssdflt : 489 #endif /* INET6 */ 490 tcp_mssdflt; 491 492 /* Set up our timeouts. */ 493 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt, 0); 494 callout_init(tp->tt_persist = &it->inp_tp_persist, 0); 495 callout_init(tp->tt_keep = &it->inp_tp_keep, 0); 496 callout_init(tp->tt_2msl = &it->inp_tp_2msl, 0); 497 callout_init(tp->tt_delack = &it->inp_tp_delack, 0); 498 499 if (tcp_do_rfc1323) 500 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 501 if (tcp_do_rfc1644) 502 tp->t_flags |= TF_REQ_CC; 503 tp->t_inpcb = inp; /* XXX */ 504 /* 505 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 506 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 507 * reasonable initial retransmit time. 508 */ 509 tp->t_srtt = TCPTV_SRTTBASE; 510 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 511 tp->t_rttmin = TCPTV_MIN; 512 tp->t_rxtcur = TCPTV_RTOBASE; 513 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 514 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 515 tp->t_rcvtime = ticks; 516 /* 517 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 518 * because the socket may be bound to an IPv6 wildcard address, 519 * which may match an IPv4-mapped IPv6 address. 520 */ 521 inp->inp_ip_ttl = ip_defttl; 522 inp->inp_ppcb = (caddr_t)tp; 523 return (tp); /* XXX */ 524 } 525 526 /* 527 * Drop a TCP connection, reporting 528 * the specified error. If connection is synchronized, 529 * then send a RST to peer. 530 */ 531 struct tcpcb * 532 tcp_drop(tp, errno) 533 register struct tcpcb *tp; 534 int errno; 535 { 536 struct socket *so = tp->t_inpcb->inp_socket; 537 538 if (TCPS_HAVERCVDSYN(tp->t_state)) { 539 tp->t_state = TCPS_CLOSED; 540 (void) tcp_output(tp); 541 tcpstat.tcps_drops++; 542 } else 543 tcpstat.tcps_conndrops++; 544 if (errno == ETIMEDOUT && tp->t_softerror) 545 errno = tp->t_softerror; 546 so->so_error = errno; 547 return (tcp_close(tp)); 548 } 549 550 /* 551 * Close a TCP control block: 552 * discard all space held by the tcp 553 * discard internet protocol block 554 * wake up any sleepers 555 */ 556 struct tcpcb * 557 tcp_close(tp) 558 register struct tcpcb *tp; 559 { 560 register struct tseg_qent *q; 561 struct inpcb *inp = tp->t_inpcb; 562 struct socket *so = inp->inp_socket; 563 #ifdef INET6 564 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 565 #endif /* INET6 */ 566 register struct rtentry *rt; 567 int dosavessthresh; 568 569 /* 570 * Make sure that all of our timers are stopped before we 571 * delete the PCB. 572 */ 573 callout_stop(tp->tt_rexmt); 574 callout_stop(tp->tt_persist); 575 callout_stop(tp->tt_keep); 576 callout_stop(tp->tt_2msl); 577 callout_stop(tp->tt_delack); 578 579 /* 580 * If we got enough samples through the srtt filter, 581 * save the rtt and rttvar in the routing entry. 582 * 'Enough' is arbitrarily defined as the 16 samples. 583 * 16 samples is enough for the srtt filter to converge 584 * to within 5% of the correct value; fewer samples and 585 * we could save a very bogus rtt. 586 * 587 * Don't update the default route's characteristics and don't 588 * update anything that the user "locked". 589 */ 590 if (tp->t_rttupdated >= 16) { 591 register u_long i = 0; 592 #ifdef INET6 593 if (isipv6) { 594 struct sockaddr_in6 *sin6; 595 596 if ((rt = inp->in6p_route.ro_rt) == NULL) 597 goto no_valid_rt; 598 sin6 = (struct sockaddr_in6 *)rt_key(rt); 599 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 600 goto no_valid_rt; 601 } 602 else 603 #endif /* INET6 */ 604 if ((rt = inp->inp_route.ro_rt) == NULL || 605 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr 606 == INADDR_ANY) 607 goto no_valid_rt; 608 609 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 610 i = tp->t_srtt * 611 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 612 if (rt->rt_rmx.rmx_rtt && i) 613 /* 614 * filter this update to half the old & half 615 * the new values, converting scale. 616 * See route.h and tcp_var.h for a 617 * description of the scaling constants. 618 */ 619 rt->rt_rmx.rmx_rtt = 620 (rt->rt_rmx.rmx_rtt + i) / 2; 621 else 622 rt->rt_rmx.rmx_rtt = i; 623 tcpstat.tcps_cachedrtt++; 624 } 625 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 626 i = tp->t_rttvar * 627 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 628 if (rt->rt_rmx.rmx_rttvar && i) 629 rt->rt_rmx.rmx_rttvar = 630 (rt->rt_rmx.rmx_rttvar + i) / 2; 631 else 632 rt->rt_rmx.rmx_rttvar = i; 633 tcpstat.tcps_cachedrttvar++; 634 } 635 /* 636 * The old comment here said: 637 * update the pipelimit (ssthresh) if it has been updated 638 * already or if a pipesize was specified & the threshhold 639 * got below half the pipesize. I.e., wait for bad news 640 * before we start updating, then update on both good 641 * and bad news. 642 * 643 * But we want to save the ssthresh even if no pipesize is 644 * specified explicitly in the route, because such 645 * connections still have an implicit pipesize specified 646 * by the global tcp_sendspace. In the absence of a reliable 647 * way to calculate the pipesize, it will have to do. 648 */ 649 i = tp->snd_ssthresh; 650 if (rt->rt_rmx.rmx_sendpipe != 0) 651 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2); 652 else 653 dosavessthresh = (i < so->so_snd.sb_hiwat / 2); 654 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 655 i != 0 && rt->rt_rmx.rmx_ssthresh != 0) 656 || dosavessthresh) { 657 /* 658 * convert the limit from user data bytes to 659 * packets then to packet data bytes. 660 */ 661 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 662 if (i < 2) 663 i = 2; 664 i *= (u_long)(tp->t_maxseg + 665 #ifdef INET6 666 (isipv6 ? sizeof (struct ip6_hdr) + 667 sizeof (struct tcphdr) : 668 #endif 669 sizeof (struct tcpiphdr) 670 #ifdef INET6 671 ) 672 #endif 673 ); 674 if (rt->rt_rmx.rmx_ssthresh) 675 rt->rt_rmx.rmx_ssthresh = 676 (rt->rt_rmx.rmx_ssthresh + i) / 2; 677 else 678 rt->rt_rmx.rmx_ssthresh = i; 679 tcpstat.tcps_cachedssthresh++; 680 } 681 } 682 rt = inp->inp_route.ro_rt; 683 if (rt) { 684 /* 685 * mark route for deletion if no information is 686 * cached. 687 */ 688 if ((tp->t_flags & TF_LQ_OVERFLOW) && 689 ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0)){ 690 if (rt->rt_rmx.rmx_rtt == 0) 691 rt->rt_flags |= RTF_DELCLONE; 692 } 693 } 694 no_valid_rt: 695 /* free the reassembly queue, if any */ 696 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 697 LIST_REMOVE(q, tqe_q); 698 m_freem(q->tqe_m); 699 FREE(q, M_TSEGQ); 700 } 701 if (tp->t_template) 702 (void) m_free(dtom(tp->t_template)); 703 inp->inp_ppcb = NULL; 704 soisdisconnected(so); 705 #ifdef INET6 706 if (INP_CHECK_SOCKAF(so, AF_INET6)) 707 in6_pcbdetach(inp); 708 else 709 #endif /* INET6 */ 710 in_pcbdetach(inp); 711 tcpstat.tcps_closed++; 712 return ((struct tcpcb *)0); 713 } 714 715 void 716 tcp_drain() 717 { 718 if (do_tcpdrain) 719 { 720 struct inpcb *inpb; 721 struct tcpcb *tcpb; 722 struct tseg_qent *te; 723 724 /* 725 * Walk the tcpbs, if existing, and flush the reassembly queue, 726 * if there is one... 727 * XXX: The "Net/3" implementation doesn't imply that the TCP 728 * reassembly queue should be flushed, but in a situation 729 * where we're really low on mbufs, this is potentially 730 * usefull. 731 */ 732 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) { 733 if ((tcpb = intotcpcb(inpb))) { 734 while ((te = LIST_FIRST(&tcpb->t_segq)) 735 != NULL) { 736 LIST_REMOVE(te, tqe_q); 737 m_freem(te->tqe_m); 738 FREE(te, M_TSEGQ); 739 } 740 } 741 } 742 } 743 } 744 745 /* 746 * Notify a tcp user of an asynchronous error; 747 * store error as soft error, but wake up user 748 * (for now, won't do anything until can select for soft error). 749 * 750 * Do not wake up user since there currently is no mechanism for 751 * reporting soft errors (yet - a kqueue filter may be added). 752 */ 753 static void 754 tcp_notify(inp, error) 755 struct inpcb *inp; 756 int error; 757 { 758 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 759 760 /* 761 * Ignore some errors if we are hooked up. 762 * If connection hasn't completed, has retransmitted several times, 763 * and receives a second error, give up now. This is better 764 * than waiting a long time to establish a connection that 765 * can never complete. 766 */ 767 if (tp->t_state == TCPS_ESTABLISHED && 768 (error == EHOSTUNREACH || error == ENETUNREACH || 769 error == EHOSTDOWN)) { 770 return; 771 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 772 tp->t_softerror) 773 tcp_drop(tp, error); 774 else 775 tp->t_softerror = error; 776 #if 0 777 wakeup((caddr_t) &so->so_timeo); 778 sorwakeup(so); 779 sowwakeup(so); 780 #endif 781 } 782 783 static int 784 tcp_pcblist(SYSCTL_HANDLER_ARGS) 785 { 786 int error, i, n, s; 787 struct inpcb *inp, **inp_list; 788 inp_gen_t gencnt; 789 struct xinpgen xig; 790 791 /* 792 * The process of preparing the TCB list is too time-consuming and 793 * resource-intensive to repeat twice on every request. 794 */ 795 if (req->oldptr == 0) { 796 n = tcbinfo.ipi_count; 797 req->oldidx = 2 * (sizeof xig) 798 + (n + n/8) * sizeof(struct xtcpcb); 799 return 0; 800 } 801 802 if (req->newptr != 0) 803 return EPERM; 804 805 /* 806 * OK, now we're committed to doing something. 807 */ 808 s = splnet(); 809 gencnt = tcbinfo.ipi_gencnt; 810 n = tcbinfo.ipi_count; 811 splx(s); 812 813 xig.xig_len = sizeof xig; 814 xig.xig_count = n; 815 xig.xig_gen = gencnt; 816 xig.xig_sogen = so_gencnt; 817 error = SYSCTL_OUT(req, &xig, sizeof xig); 818 if (error) 819 return error; 820 821 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 822 if (inp_list == 0) 823 return ENOMEM; 824 825 s = splnet(); 826 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n; 827 inp = LIST_NEXT(inp, inp_list)) { 828 if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->p, inp)) 829 inp_list[i++] = inp; 830 } 831 splx(s); 832 n = i; 833 834 error = 0; 835 for (i = 0; i < n; i++) { 836 inp = inp_list[i]; 837 if (inp->inp_gencnt <= gencnt) { 838 struct xtcpcb xt; 839 caddr_t inp_ppcb; 840 xt.xt_len = sizeof xt; 841 /* XXX should avoid extra copy */ 842 bcopy(inp, &xt.xt_inp, sizeof *inp); 843 inp_ppcb = inp->inp_ppcb; 844 if (inp_ppcb != NULL) 845 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 846 else 847 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 848 if (inp->inp_socket) 849 sotoxsocket(inp->inp_socket, &xt.xt_socket); 850 error = SYSCTL_OUT(req, &xt, sizeof xt); 851 } 852 } 853 if (!error) { 854 /* 855 * Give the user an updated idea of our state. 856 * If the generation differs from what we told 857 * her before, she knows that something happened 858 * while we were processing this request, and it 859 * might be necessary to retry. 860 */ 861 s = splnet(); 862 xig.xig_gen = tcbinfo.ipi_gencnt; 863 xig.xig_sogen = so_gencnt; 864 xig.xig_count = tcbinfo.ipi_count; 865 splx(s); 866 error = SYSCTL_OUT(req, &xig, sizeof xig); 867 } 868 free(inp_list, M_TEMP); 869 return error; 870 } 871 872 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 873 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 874 875 static int 876 tcp_getcred(SYSCTL_HANDLER_ARGS) 877 { 878 struct xucred xuc; 879 struct sockaddr_in addrs[2]; 880 struct inpcb *inp; 881 int error, s; 882 883 error = suser(req->p); 884 if (error) 885 return (error); 886 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 887 if (error) 888 return (error); 889 s = splnet(); 890 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 891 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 892 if (inp == NULL || inp->inp_socket == NULL) { 893 error = ENOENT; 894 goto out; 895 } 896 bzero(&xuc, sizeof(xuc)); 897 xuc.cr_uid = inp->inp_socket->so_cred->cr_uid; 898 xuc.cr_ngroups = inp->inp_socket->so_cred->cr_ngroups; 899 bcopy(inp->inp_socket->so_cred->cr_groups, xuc.cr_groups, 900 sizeof(xuc.cr_groups)); 901 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 902 out: 903 splx(s); 904 return (error); 905 } 906 907 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 908 0, 0, tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 909 910 #ifdef INET6 911 static int 912 tcp6_getcred(SYSCTL_HANDLER_ARGS) 913 { 914 struct xucred xuc; 915 struct sockaddr_in6 addrs[2]; 916 struct inpcb *inp; 917 int error, s, mapped = 0; 918 919 error = suser(req->p); 920 if (error) 921 return (error); 922 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 923 if (error) 924 return (error); 925 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 926 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 927 mapped = 1; 928 else 929 return (EINVAL); 930 } 931 s = splnet(); 932 if (mapped == 1) 933 inp = in_pcblookup_hash(&tcbinfo, 934 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 935 addrs[1].sin6_port, 936 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 937 addrs[0].sin6_port, 938 0, NULL); 939 else 940 inp = in6_pcblookup_hash(&tcbinfo, &addrs[1].sin6_addr, 941 addrs[1].sin6_port, 942 &addrs[0].sin6_addr, addrs[0].sin6_port, 943 0, NULL); 944 if (inp == NULL || inp->inp_socket == NULL) { 945 error = ENOENT; 946 goto out; 947 } 948 bzero(&xuc, sizeof(xuc)); 949 xuc.cr_uid = inp->inp_socket->so_cred->cr_uid; 950 xuc.cr_ngroups = inp->inp_socket->so_cred->cr_ngroups; 951 bcopy(inp->inp_socket->so_cred->cr_groups, xuc.cr_groups, 952 sizeof(xuc.cr_groups)); 953 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 954 out: 955 splx(s); 956 return (error); 957 } 958 959 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 960 0, 0, 961 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 962 #endif 963 964 965 void 966 tcp_ctlinput(cmd, sa, vip) 967 int cmd; 968 struct sockaddr *sa; 969 void *vip; 970 { 971 struct ip *ip = vip; 972 struct tcphdr *th; 973 struct in_addr faddr; 974 struct inpcb *inp; 975 struct tcpcb *tp; 976 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 977 tcp_seq icmp_seq; 978 int s; 979 980 faddr = ((struct sockaddr_in *)sa)->sin_addr; 981 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 982 return; 983 984 if (cmd == PRC_QUENCH) 985 notify = tcp_quench; 986 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 987 cmd == PRC_UNREACH_PORT) && ip) 988 notify = tcp_drop_syn_sent; 989 else if (cmd == PRC_MSGSIZE) 990 notify = tcp_mtudisc; 991 else if (PRC_IS_REDIRECT(cmd)) { 992 ip = 0; 993 notify = in_rtchange; 994 } else if (cmd == PRC_HOSTDEAD) 995 ip = 0; 996 else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0) 997 return; 998 if (ip) { 999 s = splnet(); 1000 th = (struct tcphdr *)((caddr_t)ip 1001 + (IP_VHL_HL(ip->ip_vhl) << 2)); 1002 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1003 ip->ip_src, th->th_sport, 0, NULL); 1004 if (inp != NULL && inp->inp_socket != NULL) { 1005 icmp_seq = htonl(th->th_seq); 1006 tp = intotcpcb(inp); 1007 if (SEQ_GEQ(icmp_seq, tp->snd_una) && 1008 SEQ_LT(icmp_seq, tp->snd_max)) 1009 (*notify)(inp, inetctlerrmap[cmd]); 1010 } 1011 splx(s); 1012 } else 1013 in_pcbnotifyall(&tcb, faddr, inetctlerrmap[cmd], notify); 1014 } 1015 1016 #ifdef INET6 1017 void 1018 tcp6_ctlinput(cmd, sa, d) 1019 int cmd; 1020 struct sockaddr *sa; 1021 void *d; 1022 { 1023 register struct tcphdr *thp; 1024 struct tcphdr th; 1025 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1026 struct sockaddr_in6 sa6; 1027 struct ip6_hdr *ip6; 1028 struct mbuf *m; 1029 int off; 1030 1031 if (sa->sa_family != AF_INET6 || 1032 sa->sa_len != sizeof(struct sockaddr_in6)) 1033 return; 1034 1035 if (cmd == PRC_QUENCH) 1036 notify = tcp_quench; 1037 else if (cmd == PRC_MSGSIZE) 1038 notify = tcp_mtudisc; 1039 else if (!PRC_IS_REDIRECT(cmd) && 1040 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1041 return; 1042 1043 /* if the parameter is from icmp6, decode it. */ 1044 if (d != NULL) { 1045 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 1046 m = ip6cp->ip6c_m; 1047 ip6 = ip6cp->ip6c_ip6; 1048 off = ip6cp->ip6c_off; 1049 } else { 1050 m = NULL; 1051 ip6 = NULL; 1052 off = 0; /* fool gcc */ 1053 } 1054 1055 /* 1056 * Translate addresses into internal form. 1057 * Sa check if it is AF_INET6 is done at the top of this funciton. 1058 */ 1059 sa6 = *(struct sockaddr_in6 *)sa; 1060 if (IN6_IS_ADDR_LINKLOCAL(&sa6.sin6_addr) != 0 && m != NULL && 1061 m->m_pkthdr.rcvif != NULL) 1062 sa6.sin6_addr.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 1063 1064 if (ip6) { 1065 /* 1066 * XXX: We assume that when IPV6 is non NULL, 1067 * M and OFF are valid. 1068 */ 1069 struct in6_addr s; 1070 1071 /* translate addresses into internal form */ 1072 memcpy(&s, &ip6->ip6_src, sizeof(s)); 1073 if (IN6_IS_ADDR_LINKLOCAL(&s) != 0 && m != NULL && 1074 m->m_pkthdr.rcvif != NULL) 1075 s.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 1076 1077 /* check if we can safely examine src and dst ports */ 1078 if (m->m_pkthdr.len < off + sizeof(th)) 1079 return; 1080 1081 if (m->m_len < off + sizeof(th)) { 1082 /* 1083 * this should be rare case 1084 * because now MINCLSIZE is "(MHLEN + 1)", 1085 * so we compromise on this copy... 1086 */ 1087 m_copydata(m, off, sizeof(th), (caddr_t)&th); 1088 thp = &th; 1089 } else 1090 thp = (struct tcphdr *)(mtod(m, caddr_t) + off); 1091 in6_pcbnotify(&tcb, (struct sockaddr *)&sa6, thp->th_dport, 1092 &s, thp->th_sport, cmd, notify); 1093 } else 1094 in6_pcbnotify(&tcb, (struct sockaddr *)&sa6, 0, &zeroin6_addr, 1095 0, cmd, notify); 1096 } 1097 #endif /* INET6 */ 1098 1099 #define TCP_RNDISS_ROUNDS 16 1100 #define TCP_RNDISS_OUT 7200 1101 #define TCP_RNDISS_MAX 30000 1102 1103 u_int8_t tcp_rndiss_sbox[128]; 1104 u_int16_t tcp_rndiss_msb; 1105 u_int16_t tcp_rndiss_cnt; 1106 long tcp_rndiss_reseed; 1107 1108 u_int16_t 1109 tcp_rndiss_encrypt(val) 1110 u_int16_t val; 1111 { 1112 u_int16_t sum = 0, i; 1113 1114 for (i = 0; i < TCP_RNDISS_ROUNDS; i++) { 1115 sum += 0x79b9; 1116 val ^= ((u_int16_t)tcp_rndiss_sbox[(val^sum) & 0x7f]) << 7; 1117 val = ((val & 0xff) << 7) | (val >> 8); 1118 } 1119 1120 return val; 1121 } 1122 1123 void 1124 tcp_rndiss_init() 1125 { 1126 struct timeval time; 1127 1128 getmicrotime(&time); 1129 read_random(tcp_rndiss_sbox, sizeof(tcp_rndiss_sbox)); 1130 1131 tcp_rndiss_reseed = time.tv_sec + TCP_RNDISS_OUT; 1132 tcp_rndiss_msb = tcp_rndiss_msb == 0x8000 ? 0 : 0x8000; 1133 tcp_rndiss_cnt = 0; 1134 } 1135 1136 tcp_seq 1137 tcp_rndiss_next() 1138 { 1139 u_int16_t tmp; 1140 struct timeval time; 1141 1142 getmicrotime(&time); 1143 1144 if (tcp_rndiss_cnt >= TCP_RNDISS_MAX || 1145 time.tv_sec > tcp_rndiss_reseed) 1146 tcp_rndiss_init(); 1147 1148 read_random(&tmp, sizeof(tmp)); 1149 1150 /* (tmp & 0x7fff) ensures a 32768 byte gap between ISS */ 1151 return ((tcp_rndiss_encrypt(tcp_rndiss_cnt++) | tcp_rndiss_msb) <<16) | 1152 (tmp & 0x7fff); 1153 } 1154 1155 1156 /* 1157 * When a source quench is received, close congestion window 1158 * to one segment. We will gradually open it again as we proceed. 1159 */ 1160 void 1161 tcp_quench(inp, errno) 1162 struct inpcb *inp; 1163 int errno; 1164 { 1165 struct tcpcb *tp = intotcpcb(inp); 1166 1167 if (tp) 1168 tp->snd_cwnd = tp->t_maxseg; 1169 } 1170 1171 /* 1172 * When a specific ICMP unreachable message is received and the 1173 * connection state is SYN-SENT, drop the connection. This behavior 1174 * is controlled by the icmp_may_rst sysctl. 1175 */ 1176 void 1177 tcp_drop_syn_sent(inp, errno) 1178 struct inpcb *inp; 1179 int errno; 1180 { 1181 struct tcpcb *tp = intotcpcb(inp); 1182 1183 if (tp && tp->t_state == TCPS_SYN_SENT) 1184 tcp_drop(tp, errno); 1185 } 1186 1187 /* 1188 * When `need fragmentation' ICMP is received, update our idea of the MSS 1189 * based on the new value in the route. Also nudge TCP to send something, 1190 * since we know the packet we just sent was dropped. 1191 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1192 */ 1193 void 1194 tcp_mtudisc(inp, errno) 1195 struct inpcb *inp; 1196 int errno; 1197 { 1198 struct tcpcb *tp = intotcpcb(inp); 1199 struct rtentry *rt; 1200 struct rmxp_tao *taop; 1201 struct socket *so = inp->inp_socket; 1202 int offered; 1203 int mss; 1204 #ifdef INET6 1205 int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1206 #endif /* INET6 */ 1207 1208 if (tp) { 1209 #ifdef INET6 1210 if (isipv6) 1211 rt = tcp_rtlookup6(inp); 1212 else 1213 #endif /* INET6 */ 1214 rt = tcp_rtlookup(inp); 1215 if (!rt || !rt->rt_rmx.rmx_mtu) { 1216 tp->t_maxopd = tp->t_maxseg = 1217 #ifdef INET6 1218 isipv6 ? tcp_v6mssdflt : 1219 #endif /* INET6 */ 1220 tcp_mssdflt; 1221 return; 1222 } 1223 taop = rmx_taop(rt->rt_rmx); 1224 offered = taop->tao_mssopt; 1225 mss = rt->rt_rmx.rmx_mtu - 1226 #ifdef INET6 1227 (isipv6 ? 1228 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1229 #endif /* INET6 */ 1230 sizeof(struct tcpiphdr) 1231 #ifdef INET6 1232 ) 1233 #endif /* INET6 */ 1234 ; 1235 1236 if (offered) 1237 mss = min(mss, offered); 1238 /* 1239 * XXX - The above conditional probably violates the TCP 1240 * spec. The problem is that, since we don't know the 1241 * other end's MSS, we are supposed to use a conservative 1242 * default. But, if we do that, then MTU discovery will 1243 * never actually take place, because the conservative 1244 * default is much less than the MTUs typically seen 1245 * on the Internet today. For the moment, we'll sweep 1246 * this under the carpet. 1247 * 1248 * The conservative default might not actually be a problem 1249 * if the only case this occurs is when sending an initial 1250 * SYN with options and data to a host we've never talked 1251 * to before. Then, they will reply with an MSS value which 1252 * will get recorded and the new parameters should get 1253 * recomputed. For Further Study. 1254 */ 1255 if (tp->t_maxopd <= mss) 1256 return; 1257 tp->t_maxopd = mss; 1258 1259 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1260 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1261 mss -= TCPOLEN_TSTAMP_APPA; 1262 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC && 1263 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC) 1264 mss -= TCPOLEN_CC_APPA; 1265 #if (MCLBYTES & (MCLBYTES - 1)) == 0 1266 if (mss > MCLBYTES) 1267 mss &= ~(MCLBYTES-1); 1268 #else 1269 if (mss > MCLBYTES) 1270 mss = mss / MCLBYTES * MCLBYTES; 1271 #endif 1272 if (so->so_snd.sb_hiwat < mss) 1273 mss = so->so_snd.sb_hiwat; 1274 1275 tp->t_maxseg = mss; 1276 1277 tcpstat.tcps_mturesent++; 1278 tp->t_rtttime = 0; 1279 tp->snd_nxt = tp->snd_una; 1280 tcp_output(tp); 1281 } 1282 } 1283 1284 /* 1285 * Look-up the routing entry to the peer of this inpcb. If no route 1286 * is found and it cannot be allocated the return NULL. This routine 1287 * is called by TCP routines that access the rmx structure and by tcp_mss 1288 * to get the interface MTU. 1289 */ 1290 struct rtentry * 1291 tcp_rtlookup(inp) 1292 struct inpcb *inp; 1293 { 1294 struct route *ro; 1295 struct rtentry *rt; 1296 1297 ro = &inp->inp_route; 1298 rt = ro->ro_rt; 1299 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1300 /* No route yet, so try to acquire one */ 1301 if (inp->inp_faddr.s_addr != INADDR_ANY) { 1302 ro->ro_dst.sa_family = AF_INET; 1303 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 1304 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1305 inp->inp_faddr; 1306 rtalloc(ro); 1307 rt = ro->ro_rt; 1308 } 1309 } 1310 return rt; 1311 } 1312 1313 #ifdef INET6 1314 struct rtentry * 1315 tcp_rtlookup6(inp) 1316 struct inpcb *inp; 1317 { 1318 struct route_in6 *ro6; 1319 struct rtentry *rt; 1320 1321 ro6 = &inp->in6p_route; 1322 rt = ro6->ro_rt; 1323 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1324 /* No route yet, so try to acquire one */ 1325 if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) { 1326 ro6->ro_dst.sin6_family = AF_INET6; 1327 ro6->ro_dst.sin6_len = sizeof(ro6->ro_dst); 1328 ro6->ro_dst.sin6_addr = inp->in6p_faddr; 1329 rtalloc((struct route *)ro6); 1330 rt = ro6->ro_rt; 1331 } 1332 } 1333 return rt; 1334 } 1335 #endif /* INET6 */ 1336 1337 #ifdef IPSEC 1338 /* compute ESP/AH header size for TCP, including outer IP header. */ 1339 size_t 1340 ipsec_hdrsiz_tcp(tp) 1341 struct tcpcb *tp; 1342 { 1343 struct inpcb *inp; 1344 struct mbuf *m; 1345 size_t hdrsiz; 1346 struct ip *ip; 1347 #ifdef INET6 1348 struct ip6_hdr *ip6; 1349 #endif /* INET6 */ 1350 struct tcphdr *th; 1351 1352 if (!tp || !tp->t_template || !(inp = tp->t_inpcb)) 1353 return 0; 1354 MGETHDR(m, M_DONTWAIT, MT_DATA); 1355 if (!m) 1356 return 0; 1357 1358 #ifdef INET6 1359 if ((inp->inp_vflag & INP_IPV6) != 0) { 1360 ip6 = mtod(m, struct ip6_hdr *); 1361 th = (struct tcphdr *)(ip6 + 1); 1362 m->m_pkthdr.len = m->m_len = 1363 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1364 bcopy((caddr_t)tp->t_template->tt_ipgen, (caddr_t)ip6, 1365 sizeof(struct ip6_hdr)); 1366 bcopy((caddr_t)&tp->t_template->tt_t, (caddr_t)th, 1367 sizeof(struct tcphdr)); 1368 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1369 } else 1370 #endif /* INET6 */ 1371 { 1372 ip = mtod(m, struct ip *); 1373 th = (struct tcphdr *)(ip + 1); 1374 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1375 bcopy((caddr_t)tp->t_template->tt_ipgen, (caddr_t)ip, 1376 sizeof(struct ip)); 1377 bcopy((caddr_t)&tp->t_template->tt_t, (caddr_t)th, 1378 sizeof(struct tcphdr)); 1379 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1380 } 1381 1382 m_free(m); 1383 return hdrsiz; 1384 } 1385 #endif /*IPSEC*/ 1386 1387 /* 1388 * Return a pointer to the cached information about the remote host. 1389 * The cached information is stored in the protocol specific part of 1390 * the route metrics. 1391 */ 1392 struct rmxp_tao * 1393 tcp_gettaocache(inp) 1394 struct inpcb *inp; 1395 { 1396 struct rtentry *rt; 1397 1398 #ifdef INET6 1399 if ((inp->inp_vflag & INP_IPV6) != 0) 1400 rt = tcp_rtlookup6(inp); 1401 else 1402 #endif /* INET6 */ 1403 rt = tcp_rtlookup(inp); 1404 1405 /* Make sure this is a host route and is up. */ 1406 if (rt == NULL || 1407 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)) 1408 return NULL; 1409 1410 return rmx_taop(rt->rt_rmx); 1411 } 1412 1413 /* 1414 * Clear all the TAO cache entries, called from tcp_init. 1415 * 1416 * XXX 1417 * This routine is just an empty one, because we assume that the routing 1418 * routing tables are initialized at the same time when TCP, so there is 1419 * nothing in the cache left over. 1420 */ 1421 static void 1422 tcp_cleartaocache() 1423 { 1424 } 1425