tcp_subr.c revision 1.75
1 /* $NetBSD: tcp_subr.c,v 1.75 1999/07/31 18:41:15 itojun Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc. 34 * All rights reserved. 35 * 36 * This code is derived from software contributed to The NetBSD Foundation 37 * by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation 38 * Facility, NASA Ames Research Center. 39 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 3. All advertising materials mentioning features or use of this software 49 * must display the following acknowledgement: 50 * This product includes software developed by the NetBSD 51 * Foundation, Inc. and its contributors. 52 * 4. Neither the name of The NetBSD Foundation nor the names of its 53 * contributors may be used to endorse or promote products derived 54 * from this software without specific prior written permission. 55 * 56 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 57 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 58 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 59 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 60 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 61 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 62 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 63 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 64 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 65 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 66 * POSSIBILITY OF SUCH DAMAGE. 67 */ 68 69 /* 70 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 71 * The Regents of the University of California. All rights reserved. 72 * 73 * Redistribution and use in source and binary forms, with or without 74 * modification, are permitted provided that the following conditions 75 * are met: 76 * 1. Redistributions of source code must retain the above copyright 77 * notice, this list of conditions and the following disclaimer. 78 * 2. Redistributions in binary form must reproduce the above copyright 79 * notice, this list of conditions and the following disclaimer in the 80 * documentation and/or other materials provided with the distribution. 81 * 3. All advertising materials mentioning features or use of this software 82 * must display the following acknowledgement: 83 * This product includes software developed by the University of 84 * California, Berkeley and its contributors. 85 * 4. Neither the name of the University nor the names of its contributors 86 * may be used to endorse or promote products derived from this software 87 * without specific prior written permission. 88 * 89 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 90 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 91 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 92 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 93 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 94 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 95 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 96 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 97 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 98 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 99 * SUCH DAMAGE. 100 * 101 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 102 */ 103 104 #include "opt_inet.h" 105 #include "opt_ipsec.h" 106 #include "opt_tcp_compat_42.h" 107 #include "rnd.h" 108 109 #include <sys/param.h> 110 #include <sys/proc.h> 111 #include <sys/systm.h> 112 #include <sys/malloc.h> 113 #include <sys/mbuf.h> 114 #include <sys/socket.h> 115 #include <sys/socketvar.h> 116 #include <sys/protosw.h> 117 #include <sys/errno.h> 118 #include <sys/kernel.h> 119 #include <sys/pool.h> 120 #if NRND > 0 121 #include <sys/rnd.h> 122 #endif 123 124 #include <net/route.h> 125 #include <net/if.h> 126 127 #include <netinet/in.h> 128 #include <netinet/in_systm.h> 129 #include <netinet/ip.h> 130 #include <netinet/in_pcb.h> 131 #include <netinet/ip_var.h> 132 #include <netinet/ip_icmp.h> 133 134 #ifdef INET6 135 #ifndef INET 136 #include <netinet/in.h> 137 #endif 138 #include <netinet/ip6.h> 139 #include <netinet6/in6_pcb.h> 140 #include <netinet6/ip6_var.h> 141 #include <netinet6/in6_var.h> 142 #endif 143 144 #include <netinet/tcp.h> 145 #include <netinet/tcp_fsm.h> 146 #include <netinet/tcp_seq.h> 147 #include <netinet/tcp_timer.h> 148 #include <netinet/tcp_var.h> 149 #include <netinet/tcpip.h> 150 151 #ifdef IPSEC 152 #include <netinet6/ipsec.h> 153 #endif /*IPSEC*/ 154 155 #ifdef INET6 156 struct in6pcb tcb6; 157 #endif 158 159 /* patchable/settable parameters for tcp */ 160 int tcp_mssdflt = TCP_MSS; 161 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 162 int tcp_do_rfc1323 = 1; /* window scaling / timestamps (obsolete) */ 163 int tcp_do_sack = 1; /* selective acknowledgement */ 164 int tcp_do_win_scale = 1; /* RFC1323 window scaling */ 165 int tcp_do_timestamps = 1; /* RFC1323 timestamps */ 166 int tcp_do_newreno = 0; /* Use the New Reno algorithms */ 167 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ 168 int tcp_init_win = 1; 169 int tcp_mss_ifmtu = 0; 170 #ifdef TCP_COMPAT_42 171 int tcp_compat_42 = 1; 172 #else 173 int tcp_compat_42 = 0; 174 #endif 175 176 #ifndef TCBHASHSIZE 177 #define TCBHASHSIZE 128 178 #endif 179 int tcbhashsize = TCBHASHSIZE; 180 181 int tcp_freeq __P((struct tcpcb *)); 182 183 struct pool tcpcb_pool; 184 185 /* 186 * Tcp initialization 187 */ 188 void 189 tcp_init() 190 { 191 int hlen; 192 193 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl", 194 0, NULL, NULL, M_PCB); 195 in_pcbinit(&tcbtable, tcbhashsize, tcbhashsize); 196 #ifdef INET6 197 tcb6.in6p_next = tcb6.in6p_prev = &tcb6; 198 #endif 199 LIST_INIT(&tcp_delacks); 200 201 hlen = sizeof(struct ip) + sizeof(struct tcphdr); 202 #ifdef INET6 203 if (sizeof(struct ip) < sizeof(struct ip6_hdr)) 204 hlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 205 #endif 206 if (max_protohdr < hlen) 207 max_protohdr = hlen; 208 if (max_linkhdr + hlen > MHLEN) 209 panic("tcp_init"); 210 211 /* Initialize the compressed state engine. */ 212 syn_cache_init(); 213 } 214 215 /* 216 * Create template to be used to send tcp packets on a connection. 217 * Call after host entry created, allocates an mbuf and fills 218 * in a skeletal tcp/ip header, minimizing the amount of work 219 * necessary when the connection is used. 220 */ 221 struct mbuf * 222 tcp_template(tp) 223 struct tcpcb *tp; 224 { 225 register struct inpcb *inp = tp->t_inpcb; 226 #ifdef INET6 227 register struct in6pcb *in6p = tp->t_in6pcb; 228 #endif 229 register struct tcphdr *n; 230 register struct mbuf *m; 231 int hlen; 232 233 switch (tp->t_family) { 234 case AF_INET: 235 hlen = sizeof(struct ip); 236 if (inp) 237 break; 238 #ifdef INET6 239 if (in6p) { 240 /* mapped addr case */ 241 if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_laddr) 242 && IN6_IS_ADDR_V4MAPPED(&in6p->in6p_faddr)) 243 break; 244 } 245 #endif 246 return NULL; /*EINVAL*/ 247 #ifdef INET6 248 case AF_INET6: 249 hlen = sizeof(struct ip6_hdr); 250 if (in6p) { 251 /* more sainty check? */ 252 break; 253 } 254 return NULL; /*EINVAL*/ 255 #endif 256 default: 257 hlen = 0; /*pacify gcc*/ 258 return NULL; /*EAFNOSUPPORT*/ 259 } 260 if ((m = tp->t_template) == 0) { 261 MGETHDR(m, M_DONTWAIT, MT_HEADER); 262 if (m) { 263 MCLGET(m, M_DONTWAIT); 264 if ((m->m_flags & M_EXT) == 0) { 265 m_free(m); 266 m = NULL; 267 } 268 } 269 if (m == NULL) 270 return NULL; 271 m->m_len = hlen + sizeof(struct tcphdr); 272 } 273 bzero(mtod(m, caddr_t), m->m_len); 274 switch (tp->t_family) { 275 case AF_INET: 276 { 277 struct ipovly *ipov; 278 mtod(m, struct ip *)->ip_v = 4; 279 ipov = mtod(m, struct ipovly *); 280 ipov->ih_pr = IPPROTO_TCP; 281 ipov->ih_len = htons(sizeof(struct tcphdr)); 282 if (inp) { 283 ipov->ih_src = inp->inp_laddr; 284 ipov->ih_dst = inp->inp_faddr; 285 } 286 #ifdef INET6 287 else if (in6p) { 288 /* mapped addr case */ 289 bcopy(&in6p->in6p_laddr.s6_addr32[3], &ipov->ih_src, 290 sizeof(ipov->ih_src)); 291 bcopy(&in6p->in6p_faddr.s6_addr32[3], &ipov->ih_dst, 292 sizeof(ipov->ih_dst)); 293 } 294 #endif 295 break; 296 } 297 #ifdef INET6 298 case AF_INET6: 299 { 300 struct ip6_hdr *ip6; 301 mtod(m, struct ip *)->ip_v = 6; 302 ip6 = mtod(m, struct ip6_hdr *); 303 ip6->ip6_nxt = IPPROTO_TCP; 304 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 305 ip6->ip6_src = in6p->in6p_laddr; 306 ip6->ip6_dst = in6p->in6p_faddr; 307 ip6->ip6_flow = in6p->in6p_flowinfo & IPV6_FLOWINFO_MASK; 308 if (ip6_auto_flowlabel) { 309 ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK; 310 ip6->ip6_flow |= 311 (htonl(ip6_flow_seq++) & IPV6_FLOWLABEL_MASK); 312 } 313 ip6->ip6_vfc = IPV6_VERSION; 314 break; 315 } 316 #endif 317 } 318 n = (struct tcphdr *)(mtod(m, caddr_t) + hlen); 319 if (inp) { 320 n->th_sport = inp->inp_lport; 321 n->th_dport = inp->inp_fport; 322 } 323 #ifdef INET6 324 else if (in6p) { 325 n->th_sport = in6p->in6p_lport; 326 n->th_dport = in6p->in6p_fport; 327 } 328 #endif 329 n->th_seq = 0; 330 n->th_ack = 0; 331 n->th_x2 = 0; 332 n->th_off = 5; 333 n->th_flags = 0; 334 n->th_win = 0; 335 n->th_sum = 0; 336 n->th_urp = 0; 337 return (m); 338 } 339 340 /* 341 * Send a single message to the TCP at address specified by 342 * the given TCP/IP header. If m == 0, then we make a copy 343 * of the tcpiphdr at ti and send directly to the addressed host. 344 * This is used to force keep alive messages out using the TCP 345 * template for a connection tp->t_template. If flags are given 346 * then we send a message back to the TCP which originated the 347 * segment ti, and discard the mbuf containing it and any other 348 * attached mbufs. 349 * 350 * In any case the ack and sequence number of the transmitted 351 * segment are as specified by the parameters. 352 */ 353 int 354 tcp_respond(tp, template, m, th0, ack, seq, flags) 355 struct tcpcb *tp; 356 struct mbuf *template; 357 register struct mbuf *m; 358 struct tcphdr *th0; 359 tcp_seq ack, seq; 360 int flags; 361 { 362 #ifndef INET6 363 struct route iproute; 364 #else 365 struct route_in6 iproute; /* sizeof(route_in6) > sizeof(route) */ 366 #endif 367 struct route *ro; 368 struct rtentry *rt; 369 int error, tlen, win = 0; 370 int hlen; 371 struct ip *ip; 372 #ifdef INET6 373 struct ip6_hdr *ip6; 374 #endif 375 int family; /* family on packet, not inpcb/in6pcb! */ 376 struct tcphdr *th; 377 378 if (tp != NULL && (flags & TH_RST) == 0) { 379 if (tp->t_inpcb) 380 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 381 #ifdef INET6 382 else if (tp->t_in6pcb) 383 win = sbspace(&tp->t_in6pcb->in6p_socket->so_rcv); 384 #endif 385 } 386 387 ip = NULL; 388 #ifdef INET6 389 ip6 = NULL; 390 #endif 391 if (m == 0) { 392 if (!template) 393 return EINVAL; 394 395 /* get family information from template */ 396 switch (mtod(template, struct ip *)->ip_v) { 397 case 4: 398 family = AF_INET; 399 hlen = sizeof(struct ip); 400 break; 401 #ifdef INET6 402 case 6: 403 family = AF_INET6; 404 hlen = sizeof(struct ip6_hdr); 405 break; 406 #endif 407 default: 408 return EAFNOSUPPORT; 409 } 410 411 MGETHDR(m, M_DONTWAIT, MT_HEADER); 412 if (m) { 413 MCLGET(m, M_DONTWAIT); 414 if ((m->m_flags & M_EXT) == 0) { 415 m_free(m); 416 m = NULL; 417 } 418 } 419 if (m == NULL) 420 return (ENOBUFS); 421 422 if (tcp_compat_42) 423 tlen = 1; 424 else 425 tlen = 0; 426 427 m->m_data += max_linkhdr; 428 bcopy(mtod(template, caddr_t), mtod(m, caddr_t), 429 template->m_len); 430 switch (family) { 431 case AF_INET: 432 ip = mtod(m, struct ip *); 433 th = (struct tcphdr *)(ip + 1); 434 break; 435 #ifdef INET6 436 case AF_INET6: 437 ip6 = mtod(m, struct ip6_hdr *); 438 th = (struct tcphdr *)(ip6 + 1); 439 break; 440 #endif 441 default: /*pacify gcc*/ 442 ip = NULL; 443 #ifdef INET6 444 ip6 = NULL; 445 #endif 446 th = NULL; 447 break; 448 } 449 flags = TH_ACK; 450 } else { 451 /* get family information from m */ 452 switch (mtod(m, struct ip *)->ip_v) { 453 case 4: 454 family = AF_INET; 455 hlen = sizeof(struct ip); 456 break; 457 #ifdef INET6 458 case 6: 459 family = AF_INET6; 460 hlen = sizeof(struct ip6_hdr); 461 break; 462 #endif 463 default: 464 if (m) 465 m_freem(m); 466 return EAFNOSUPPORT; 467 } 468 469 /* template pointer almost has no meaning */ 470 m_freem(m->m_next); 471 m->m_next = 0; 472 m->m_len = hlen + sizeof(struct tcphdr); 473 if ((m->m_flags & M_PKTHDR) == 0) { 474 printf("non PKTHDR to tcp_respond\n"); 475 m_freem(m); 476 return EINVAL; 477 } 478 479 tlen = 0; 480 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 481 switch (family) { 482 case AF_INET: 483 ip = mtod(m, struct ip *); 484 th = (struct tcphdr *)(ip + 1); 485 xchg(ip->ip_dst, ip->ip_src, struct in_addr); 486 ip->ip_p = IPPROTO_TCP; 487 break; 488 #ifdef INET6 489 case AF_INET6: 490 ip6 = mtod(m, struct ip6_hdr *); 491 th = (struct tcphdr *)(ip6 + 1); 492 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 493 ip6->ip6_nxt = IPPROTO_TCP; 494 break; 495 #endif 496 } 497 *th = *th0; 498 xchg(th->th_dport, th->th_sport, u_int16_t); 499 #undef xchg 500 } 501 th->th_seq = htonl(seq); 502 th->th_ack = htonl(ack); 503 th->th_x2 = 0; 504 if ((flags & TH_SYN) == 0) { 505 if (tp) 506 th->th_win = htons((u_int16_t) (win >> tp->rcv_scale)); 507 else 508 th->th_win = htons((u_int16_t)win); 509 th->th_off = sizeof (struct tcphdr) >> 2; 510 tlen += sizeof (struct tcphdr); 511 } else 512 tlen += th->th_off << 2; 513 m->m_len = hlen + tlen; 514 m->m_pkthdr.len = hlen + tlen; 515 m->m_pkthdr.rcvif = (struct ifnet *) 0; 516 th->th_flags = flags; 517 th->th_urp = 0; 518 519 switch (family) { 520 case AF_INET: 521 { 522 struct ipovly *ipov = (struct ipovly *)ip; 523 bzero(ipov->ih_x1, sizeof ipov->ih_x1); 524 ipov->ih_len = htons((u_int16_t)tlen); 525 526 th->th_sum = 0; 527 th->th_sum = in_cksum(m, hlen + tlen); 528 ip->ip_len = hlen + tlen; /*will be flipped on output*/ 529 ip->ip_ttl = ip_defttl; 530 break; 531 } 532 #ifdef INET6 533 case AF_INET6: 534 { 535 th->th_sum = 0; 536 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), 537 tlen); 538 ip6->ip6_plen = ntohs(tlen); 539 ip6->ip6_hlim = ip6_defhlim; 540 ip6->ip6_flow &= ~IPV6_FLOWINFO_MASK; 541 if (ip6_auto_flowlabel) { 542 ip6->ip6_flow |= 543 (htonl(ip6_flow_seq++) & IPV6_FLOWLABEL_MASK); 544 } 545 break; 546 } 547 #endif 548 } 549 550 #ifdef IPSEC 551 m->m_pkthdr.rcvif = NULL; 552 #endif /*IPSEC*/ 553 554 /* 555 * If we're doing Path MTU discovery, we need to set DF unless 556 * the route's MTU is locked. If we lack a route, we need to 557 * look it up now. 558 * 559 * ip_output() could do this for us, but it's convenient to just 560 * do it here unconditionally. 561 */ 562 if (tp != NULL && tp->t_inpcb != NULL) { 563 ro = &tp->t_inpcb->inp_route; 564 #ifdef IPSEC 565 m->m_pkthdr.rcvif = (struct ifnet *)tp->t_inpcb->inp_socket; 566 #endif 567 #ifdef DIAGNOSTIC 568 if (family != AF_INET) 569 panic("tcp_respond: address family mismatch"); 570 if (!in_hosteq(ip->ip_dst, tp->t_inpcb->inp_faddr)) { 571 panic("tcp_respond: ip_dst %x != inp_faddr %x", 572 ntohl(ip->ip_dst.s_addr), 573 ntohl(tp->t_inpcb->inp_faddr.s_addr)); 574 } 575 #endif 576 } 577 #ifdef INET6 578 else if (tp != NULL && tp->t_in6pcb != NULL) { 579 ro = (struct route *)&tp->t_in6pcb->in6p_route; 580 #ifdef IPSEC 581 m->m_pkthdr.rcvif = (struct ifnet *)tp->t_in6pcb->in6p_socket; 582 #endif 583 #ifdef DIAGNOSTIC 584 if (family == AF_INET) { 585 if (!IN6_IS_ADDR_V4MAPPED(&tp->t_in6pcb->in6p_faddr)) 586 panic("tcp_respond: not mapped addr"); 587 if (bcmp(&ip->ip_dst, 588 &tp->t_in6pcb->in6p_faddr.s6_addr32[3], 589 sizeof(ip->ip_dst)) != 0) { 590 panic("tcp_respond: ip_dst != in6p_faddr"); 591 } 592 } else if (family == AF_INET6) { 593 if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &tp->t_in6pcb->in6p_faddr)) 594 panic("tcp_respond: ip6_dst != in6p_faddr"); 595 } else 596 panic("tcp_respond: address family mismatch"); 597 #endif 598 } 599 #endif 600 else { 601 ro = (struct route *)&iproute; 602 bzero(ro, sizeof(iproute)); 603 } 604 if ((rt = ro->ro_rt) == NULL || (rt->rt_flags & RTF_UP) == 0) { 605 if (ro->ro_rt != NULL) { 606 RTFREE(ro->ro_rt); 607 ro->ro_rt = NULL; 608 } 609 switch (family) { 610 case AF_INET: 611 { 612 struct sockaddr_in *dst; 613 dst = satosin(&ro->ro_dst); 614 dst->sin_family = AF_INET; 615 dst->sin_len = sizeof(*dst); 616 dst->sin_addr = ip->ip_dst; 617 break; 618 } 619 #ifdef INET6 620 case AF_INET6: 621 { 622 struct sockaddr_in6 *dst; 623 dst = satosin6(&ro->ro_dst); 624 bzero(dst, sizeof(*dst)); 625 dst->sin6_family = AF_INET6; 626 dst->sin6_len = sizeof(*dst); 627 dst->sin6_addr = ip6->ip6_dst; 628 break; 629 } 630 #endif 631 } 632 rtalloc(ro); 633 if ((rt = ro->ro_rt) == NULL) { 634 m_freem(m); 635 switch (family) { 636 case AF_INET: 637 ipstat.ips_noroute++; 638 break; 639 #ifdef INET6 640 case AF_INET6: 641 ip6stat.ip6s_noroute++; 642 break; 643 #endif 644 } 645 return (EHOSTUNREACH); 646 } 647 } 648 switch (family) { 649 case AF_INET: 650 if (ip_mtudisc != 0 && (rt->rt_rmx.rmx_locks & RTV_MTU) == 0) 651 ip->ip_off |= IP_DF; 652 653 error = ip_output(m, NULL, ro, 0, NULL); 654 break; 655 #ifdef INET6 656 case AF_INET6: 657 error = ip6_output(m, NULL, (struct route_in6 *)ro, 0, NULL); 658 break; 659 #endif 660 default: 661 error = EAFNOSUPPORT; 662 break; 663 } 664 665 if (ro == (struct route *)&iproute) { 666 RTFREE(ro->ro_rt); 667 ro->ro_rt = NULL; 668 } 669 670 return (error); 671 } 672 673 /* 674 * Create a new TCP control block, making an 675 * empty reassembly queue and hooking it to the argument 676 * protocol control block. 677 */ 678 struct tcpcb * 679 tcp_newtcpcb(family, aux) 680 int family; /* selects inpcb, or in6pcb */ 681 void *aux; 682 { 683 register struct tcpcb *tp; 684 685 switch (family) { 686 case PF_INET: 687 break; 688 #ifdef INET6 689 case PF_INET6: 690 break; 691 #endif 692 default: 693 return NULL; 694 } 695 696 tp = pool_get(&tcpcb_pool, PR_NOWAIT); 697 if (tp == NULL) 698 return (NULL); 699 bzero((caddr_t)tp, sizeof(struct tcpcb)); 700 LIST_INIT(&tp->segq); 701 LIST_INIT(&tp->timeq); 702 tp->t_family = family; /* may be overridden later on */ 703 tp->t_peermss = tcp_mssdflt; 704 tp->t_ourmss = tcp_mssdflt; 705 tp->t_segsz = tcp_mssdflt; 706 707 tp->t_flags = 0; 708 if (tcp_do_rfc1323 && tcp_do_win_scale) 709 tp->t_flags |= TF_REQ_SCALE; 710 if (tcp_do_rfc1323 && tcp_do_timestamps) 711 tp->t_flags |= TF_REQ_TSTMP; 712 if (tcp_do_sack == 2) 713 tp->t_flags |= TF_WILL_SACK; 714 else if (tcp_do_sack == 1) 715 tp->t_flags |= TF_WILL_SACK|TF_IGNR_RXSACK; 716 tp->t_flags |= TF_CANT_TXSACK; 717 switch (family) { 718 case PF_INET: 719 tp->t_inpcb = (struct inpcb *)aux; 720 break; 721 #ifdef INET6 722 case PF_INET6: 723 tp->t_in6pcb = (struct in6pcb *)aux; 724 break; 725 #endif 726 } 727 /* 728 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 729 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 730 * reasonable initial retransmit time. 731 */ 732 tp->t_srtt = TCPTV_SRTTBASE; 733 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1); 734 tp->t_rttmin = TCPTV_MIN; 735 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 736 TCPTV_MIN, TCPTV_REXMTMAX); 737 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 738 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 739 if (family == AF_INET) { 740 struct inpcb *inp = (struct inpcb *)aux; 741 inp->inp_ip.ip_ttl = ip_defttl; 742 inp->inp_ppcb = (caddr_t)tp; 743 } 744 #ifdef INET6 745 else if (family == AF_INET6) { 746 struct in6pcb *in6p = (struct in6pcb *)aux; 747 in6p->in6p_ip6.ip6_hlim = ip6_defhlim; 748 in6p->in6p_ppcb = (caddr_t)tp; 749 } 750 #endif 751 return (tp); 752 } 753 754 /* 755 * Drop a TCP connection, reporting 756 * the specified error. If connection is synchronized, 757 * then send a RST to peer. 758 */ 759 struct tcpcb * 760 tcp_drop(tp, errno) 761 register struct tcpcb *tp; 762 int errno; 763 { 764 struct socket *so; 765 766 if (tp->t_inpcb) 767 so = tp->t_inpcb->inp_socket; 768 #ifdef INET6 769 else if (tp->t_in6pcb) 770 so = tp->t_in6pcb->in6p_socket; 771 #endif 772 else 773 return NULL; 774 775 if (TCPS_HAVERCVDSYN(tp->t_state)) { 776 tp->t_state = TCPS_CLOSED; 777 (void) tcp_output(tp); 778 tcpstat.tcps_drops++; 779 } else 780 tcpstat.tcps_conndrops++; 781 if (errno == ETIMEDOUT && tp->t_softerror) 782 errno = tp->t_softerror; 783 so->so_error = errno; 784 return (tcp_close(tp)); 785 } 786 787 /* 788 * Close a TCP control block: 789 * discard all space held by the tcp 790 * discard internet protocol block 791 * wake up any sleepers 792 */ 793 struct tcpcb * 794 tcp_close(tp) 795 register struct tcpcb *tp; 796 { 797 struct inpcb *inp; 798 #ifdef INET6 799 struct in6pcb *in6p; 800 #endif 801 struct socket *so; 802 #ifdef RTV_RTT 803 register struct rtentry *rt; 804 #endif 805 struct route *ro; 806 807 inp = tp->t_inpcb; 808 #ifdef INET6 809 in6p = tp->t_in6pcb; 810 #endif 811 so = NULL; 812 ro = NULL; 813 if (inp) { 814 so = inp->inp_socket; 815 ro = &inp->inp_route; 816 } 817 #ifdef INET6 818 else if (in6p) { 819 so = in6p->in6p_socket; 820 ro = (struct route *)&in6p->in6p_route; 821 } 822 #endif 823 824 #ifdef RTV_RTT 825 /* 826 * If we sent enough data to get some meaningful characteristics, 827 * save them in the routing entry. 'Enough' is arbitrarily 828 * defined as the sendpipesize (default 4K) * 16. This would 829 * give us 16 rtt samples assuming we only get one sample per 830 * window (the usual case on a long haul net). 16 samples is 831 * enough for the srtt filter to converge to within 5% of the correct 832 * value; fewer samples and we could save a very bogus rtt. 833 * 834 * Don't update the default route's characteristics and don't 835 * update anything that the user "locked". 836 */ 837 if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) && 838 ro && (rt = ro->ro_rt) && 839 !in_nullhost(satosin(rt_key(rt))->sin_addr)) { 840 register u_long i = 0; 841 842 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 843 i = tp->t_srtt * 844 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 845 if (rt->rt_rmx.rmx_rtt && i) 846 /* 847 * filter this update to half the old & half 848 * the new values, converting scale. 849 * See route.h and tcp_var.h for a 850 * description of the scaling constants. 851 */ 852 rt->rt_rmx.rmx_rtt = 853 (rt->rt_rmx.rmx_rtt + i) / 2; 854 else 855 rt->rt_rmx.rmx_rtt = i; 856 } 857 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 858 i = tp->t_rttvar * 859 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2)); 860 if (rt->rt_rmx.rmx_rttvar && i) 861 rt->rt_rmx.rmx_rttvar = 862 (rt->rt_rmx.rmx_rttvar + i) / 2; 863 else 864 rt->rt_rmx.rmx_rttvar = i; 865 } 866 /* 867 * update the pipelimit (ssthresh) if it has been updated 868 * already or if a pipesize was specified & the threshhold 869 * got below half the pipesize. I.e., wait for bad news 870 * before we start updating, then update on both good 871 * and bad news. 872 */ 873 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 874 (i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) || 875 i < (rt->rt_rmx.rmx_sendpipe / 2)) { 876 /* 877 * convert the limit from user data bytes to 878 * packets then to packet data bytes. 879 */ 880 i = (i + tp->t_segsz / 2) / tp->t_segsz; 881 if (i < 2) 882 i = 2; 883 i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr)); 884 if (rt->rt_rmx.rmx_ssthresh) 885 rt->rt_rmx.rmx_ssthresh = 886 (rt->rt_rmx.rmx_ssthresh + i) / 2; 887 else 888 rt->rt_rmx.rmx_ssthresh = i; 889 } 890 } 891 #endif /* RTV_RTT */ 892 /* free the reassembly queue, if any */ 893 TCP_REASS_LOCK(tp); 894 (void) tcp_freeq(tp); 895 TCP_REASS_UNLOCK(tp); 896 897 TCP_CLEAR_DELACK(tp); 898 899 if (tp->t_template) { 900 m_free(tp->t_template); 901 tp->t_template = NULL; 902 } 903 pool_put(&tcpcb_pool, tp); 904 if (inp) { 905 inp->inp_ppcb = 0; 906 soisdisconnected(so); 907 in_pcbdetach(inp); 908 } 909 #ifdef INET6 910 else if (in6p) { 911 in6p->in6p_ppcb = 0; 912 soisdisconnected(so); 913 in6_pcbdetach(in6p); 914 } 915 #endif 916 tcpstat.tcps_closed++; 917 return ((struct tcpcb *)0); 918 } 919 920 int 921 tcp_freeq(tp) 922 struct tcpcb *tp; 923 { 924 register struct ipqent *qe; 925 int rv = 0; 926 #ifdef TCPREASS_DEBUG 927 int i = 0; 928 #endif 929 930 TCP_REASS_LOCK_CHECK(tp); 931 932 while ((qe = tp->segq.lh_first) != NULL) { 933 #ifdef TCPREASS_DEBUG 934 printf("tcp_freeq[%p,%d]: %u:%u(%u) 0x%02x\n", 935 tp, i++, qe->ipqe_seq, qe->ipqe_seq + qe->ipqe_len, 936 qe->ipqe_len, qe->ipqe_flags & (TH_SYN|TH_FIN|TH_RST)); 937 #endif 938 LIST_REMOVE(qe, ipqe_q); 939 LIST_REMOVE(qe, ipqe_timeq); 940 m_freem(qe->ipqe_m); 941 pool_put(&ipqent_pool, qe); 942 rv = 1; 943 } 944 return (rv); 945 } 946 947 /* 948 * Protocol drain routine. Called when memory is in short supply. 949 */ 950 void 951 tcp_drain() 952 { 953 register struct inpcb *inp; 954 register struct tcpcb *tp; 955 956 /* 957 * Free the sequence queue of all TCP connections. 958 */ 959 inp = tcbtable.inpt_queue.cqh_first; 960 if (inp) /* XXX */ 961 for (; inp != (struct inpcb *)&tcbtable.inpt_queue; 962 inp = inp->inp_queue.cqe_next) { 963 if ((tp = intotcpcb(inp)) != NULL) { 964 /* 965 * We may be called from a device's interrupt 966 * context. If the tcpcb is already busy, 967 * just bail out now. 968 */ 969 if (tcp_reass_lock_try(tp) == 0) 970 continue; 971 if (tcp_freeq(tp)) 972 tcpstat.tcps_connsdrained++; 973 TCP_REASS_UNLOCK(tp); 974 } 975 } 976 } 977 978 /* 979 * Notify a tcp user of an asynchronous error; 980 * store error as soft error, but wake up user 981 * (for now, won't do anything until can select for soft error). 982 */ 983 void 984 tcp_notify(inp, error) 985 struct inpcb *inp; 986 int error; 987 { 988 register struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 989 register struct socket *so = inp->inp_socket; 990 991 /* 992 * Ignore some errors if we are hooked up. 993 * If connection hasn't completed, has retransmitted several times, 994 * and receives a second error, give up now. This is better 995 * than waiting a long time to establish a connection that 996 * can never complete. 997 */ 998 if (tp->t_state == TCPS_ESTABLISHED && 999 (error == EHOSTUNREACH || error == ENETUNREACH || 1000 error == EHOSTDOWN)) { 1001 return; 1002 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1003 tp->t_rxtshift > 3 && tp->t_softerror) 1004 so->so_error = error; 1005 else 1006 tp->t_softerror = error; 1007 wakeup((caddr_t) &so->so_timeo); 1008 sorwakeup(so); 1009 sowwakeup(so); 1010 } 1011 1012 #if defined(INET6) && !defined(TCP6) 1013 void 1014 tcp6_notify(in6p, error) 1015 struct in6pcb *in6p; 1016 int error; 1017 { 1018 register struct tcpcb *tp = (struct tcpcb *)in6p->in6p_ppcb; 1019 register struct socket *so = in6p->in6p_socket; 1020 1021 /* 1022 * Ignore some errors if we are hooked up. 1023 * If connection hasn't completed, has retransmitted several times, 1024 * and receives a second error, give up now. This is better 1025 * than waiting a long time to establish a connection that 1026 * can never complete. 1027 */ 1028 if (tp->t_state == TCPS_ESTABLISHED && 1029 (error == EHOSTUNREACH || error == ENETUNREACH || 1030 error == EHOSTDOWN)) { 1031 return; 1032 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1033 tp->t_rxtshift > 3 && tp->t_softerror) 1034 so->so_error = error; 1035 else 1036 tp->t_softerror = error; 1037 wakeup((caddr_t) &so->so_timeo); 1038 sorwakeup(so); 1039 sowwakeup(so); 1040 } 1041 #endif 1042 1043 #if defined(INET6) && !defined(TCP6) 1044 void 1045 tcp6_ctlinput(cmd, sa, ip6, m, off) 1046 int cmd; 1047 struct sockaddr *sa; 1048 register struct ip6_hdr *ip6; 1049 struct mbuf *m; 1050 int off; 1051 { 1052 register struct tcphdr *thp; 1053 struct tcphdr th; 1054 void (*notify) __P((struct in6pcb *, int)) = tcp6_notify; 1055 int nmatch; 1056 extern struct in6_addr zeroin6_addr; /* netinet6/in6_pcb.c */ 1057 struct sockaddr_in6 sa6; 1058 1059 if (cmd == PRC_QUENCH) 1060 notify = tcp6_quench; 1061 else if (cmd == PRC_MSGSIZE) 1062 notify = tcp6_mtudisc; 1063 else if (!PRC_IS_REDIRECT(cmd) && 1064 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1065 return; 1066 1067 /* translate addresses into internal form */ 1068 sa6 = *(struct sockaddr_in6 *)sa; 1069 if (IN6_IS_ADDR_LINKLOCAL(&sa6.sin6_addr)) 1070 sa6.sin6_addr.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 1071 1072 if (ip6) { 1073 /* 1074 * XXX: We assume that when ip6 is non NULL, 1075 * M and OFF are valid. 1076 */ 1077 struct in6_addr s; 1078 1079 /* translate addresses into internal form */ 1080 memcpy(&s, &ip6->ip6_dst, sizeof(s)); 1081 if (IN6_IS_ADDR_LINKLOCAL(&s)) 1082 s.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 1083 1084 if (m->m_len < off + sizeof(th)) { 1085 /* 1086 * this should be rare case, 1087 * so we compromise on this copy... 1088 */ 1089 m_copydata(m, off, sizeof(th), (caddr_t)&th); 1090 thp = &th; 1091 } else 1092 thp = (struct tcphdr *)(mtod(m, caddr_t) + off); 1093 nmatch = in6_pcbnotify(&tcb6, (struct sockaddr *)&sa6, 1094 thp->th_dport, &s, thp->th_sport, cmd, notify); 1095 if (nmatch == 0 && syn_cache_count && 1096 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 1097 inet6ctlerrmap[cmd] == ENETUNREACH || 1098 inet6ctlerrmap[cmd] == EHOSTDOWN)) { 1099 struct sockaddr_in6 sin6; 1100 bzero(&sin6, sizeof(sin6)); 1101 sin6.sin6_len = sizeof(sin6); 1102 sin6.sin6_family = AF_INET6; 1103 sin6.sin6_port = thp->th_sport; 1104 sin6.sin6_addr = s; 1105 syn_cache_unreach((struct sockaddr *)&sin6, sa, thp); 1106 } 1107 } else { 1108 (void) in6_pcbnotify(&tcb6, (struct sockaddr *)&sa6, 0, 1109 &zeroin6_addr, 0, cmd, notify); 1110 } 1111 } 1112 #endif 1113 1114 /* assumes that ip header and tcp header are contiguous on mbuf */ 1115 void * 1116 tcp_ctlinput(cmd, sa, v) 1117 int cmd; 1118 struct sockaddr *sa; 1119 register void *v; 1120 { 1121 register struct ip *ip = v; 1122 register struct tcphdr *th; 1123 extern int inetctlerrmap[]; 1124 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1125 int errno; 1126 int nmatch; 1127 1128 if ((unsigned)cmd >= PRC_NCMDS) 1129 return NULL; 1130 errno = inetctlerrmap[cmd]; 1131 if (cmd == PRC_QUENCH) 1132 notify = tcp_quench; 1133 else if (PRC_IS_REDIRECT(cmd)) 1134 notify = in_rtchange, ip = 0; 1135 else if (cmd == PRC_MSGSIZE && ip_mtudisc) 1136 notify = tcp_mtudisc, ip = 0; 1137 else if (cmd == PRC_HOSTDEAD) 1138 ip = 0; 1139 else if (errno == 0) 1140 return NULL; 1141 if (ip && ip->ip_v == 4 && sa->sa_family == AF_INET) { 1142 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1143 nmatch = in_pcbnotify(&tcbtable, satosin(sa)->sin_addr, 1144 th->th_dport, ip->ip_src, th->th_sport, errno, notify); 1145 if (nmatch == 0 && syn_cache_count && 1146 (inetctlerrmap[cmd] == EHOSTUNREACH || 1147 inetctlerrmap[cmd] == ENETUNREACH || 1148 inetctlerrmap[cmd] == EHOSTDOWN)) { 1149 struct sockaddr_in sin; 1150 bzero(&sin, sizeof(sin)); 1151 sin.sin_len = sizeof(sin); 1152 sin.sin_family = AF_INET; 1153 sin.sin_port = th->th_sport; 1154 sin.sin_addr = ip->ip_src; 1155 syn_cache_unreach((struct sockaddr *)&sin, sa, th); 1156 } 1157 1158 /* XXX mapped address case */ 1159 } 1160 else { 1161 (void)in_pcbnotifyall(&tcbtable, satosin(sa)->sin_addr, errno, 1162 notify); 1163 } 1164 return NULL; 1165 } 1166 1167 /* 1168 * When a source quence is received, we are being notifed of congestion. 1169 * Close the congestion window down to the Loss Window (one segment). 1170 * We will gradually open it again as we proceed. 1171 */ 1172 void 1173 tcp_quench(inp, errno) 1174 struct inpcb *inp; 1175 int errno; 1176 { 1177 struct tcpcb *tp = intotcpcb(inp); 1178 1179 if (tp) 1180 tp->snd_cwnd = tp->t_segsz; 1181 } 1182 1183 #if defined(INET6) && !defined(TCP6) 1184 void 1185 tcp6_quench(in6p, errno) 1186 struct in6pcb *in6p; 1187 int errno; 1188 { 1189 struct tcpcb *tp = in6totcpcb(in6p); 1190 1191 if (tp) 1192 tp->snd_cwnd = tp->t_segsz; 1193 } 1194 #endif 1195 1196 /* 1197 * On receipt of path MTU corrections, flush old route and replace it 1198 * with the new one. Retransmit all unacknowledged packets, to ensure 1199 * that all packets will be received. 1200 */ 1201 void 1202 tcp_mtudisc(inp, errno) 1203 struct inpcb *inp; 1204 int errno; 1205 { 1206 struct tcpcb *tp = intotcpcb(inp); 1207 struct rtentry *rt = in_pcbrtentry(inp); 1208 1209 if (tp != 0) { 1210 if (rt != 0) { 1211 /* 1212 * If this was not a host route, remove and realloc. 1213 */ 1214 if ((rt->rt_flags & RTF_HOST) == 0) { 1215 in_rtchange(inp, errno); 1216 if ((rt = in_pcbrtentry(inp)) == 0) 1217 return; 1218 } 1219 1220 /* 1221 * Slow start out of the error condition. We 1222 * use the MTU because we know it's smaller 1223 * than the previously transmitted segment. 1224 * 1225 * Note: This is more conservative than the 1226 * suggestion in draft-floyd-incr-init-win-03. 1227 */ 1228 if (rt->rt_rmx.rmx_mtu != 0) 1229 tp->snd_cwnd = 1230 TCP_INITIAL_WINDOW(tcp_init_win, 1231 rt->rt_rmx.rmx_mtu); 1232 } 1233 1234 /* 1235 * Resend unacknowledged packets. 1236 */ 1237 tp->snd_nxt = tp->snd_una; 1238 tcp_output(tp); 1239 } 1240 } 1241 1242 #if defined(INET6) && !defined(TCP6) 1243 void 1244 tcp6_mtudisc(in6p, errno) 1245 struct in6pcb *in6p; 1246 int errno; 1247 { 1248 struct tcpcb *tp = in6totcpcb(in6p); 1249 struct rtentry *rt = in6_pcbrtentry(in6p); 1250 1251 if (tp != 0) { 1252 if (rt != 0) { 1253 /* 1254 * If this was not a host route, remove and realloc. 1255 */ 1256 if ((rt->rt_flags & RTF_HOST) == 0) { 1257 in6_rtchange(in6p, errno); 1258 if ((rt = in6_pcbrtentry(in6p)) == 0) 1259 return; 1260 } 1261 1262 /* 1263 * Slow start out of the error condition. We 1264 * use the MTU because we know it's smaller 1265 * than the previously transmitted segment. 1266 * 1267 * Note: This is more conservative than the 1268 * suggestion in draft-floyd-incr-init-win-03. 1269 */ 1270 if (rt->rt_rmx.rmx_mtu != 0) 1271 tp->snd_cwnd = 1272 TCP_INITIAL_WINDOW(tcp_init_win, 1273 rt->rt_rmx.rmx_mtu); 1274 } 1275 1276 /* 1277 * Resend unacknowledged packets. 1278 */ 1279 tp->snd_nxt = tp->snd_una; 1280 tcp_output(tp); 1281 } 1282 } 1283 #endif 1284 1285 /* 1286 * Compute the MSS to advertise to the peer. Called only during 1287 * the 3-way handshake. If we are the server (peer initiated 1288 * connection), we are called with a pointer to the interface 1289 * on which the SYN packet arrived. If we are the client (we 1290 * initiated connection), we are called with a pointer to the 1291 * interface out which this connection should go. 1292 */ 1293 u_long 1294 tcp_mss_to_advertise(ifp) 1295 const struct ifnet *ifp; 1296 { 1297 extern u_long in_maxmtu; 1298 u_long mss = 0; 1299 1300 /* 1301 * In order to avoid defeating path MTU discovery on the peer, 1302 * we advertise the max MTU of all attached networks as our MSS, 1303 * per RFC 1191, section 3.1. 1304 * 1305 * We provide the option to advertise just the MTU of 1306 * the interface on which we hope this connection will 1307 * be receiving. If we are responding to a SYN, we 1308 * will have a pretty good idea about this, but when 1309 * initiating a connection there is a bit more doubt. 1310 * 1311 * We also need to ensure that loopback has a large enough 1312 * MSS, as the loopback MTU is never included in in_maxmtu. 1313 */ 1314 1315 if (ifp != NULL) 1316 mss = ifp->if_mtu; 1317 1318 if (tcp_mss_ifmtu == 0) 1319 mss = max(in_maxmtu, mss); 1320 1321 if (mss > sizeof(struct tcpiphdr)) 1322 mss -= sizeof(struct tcpiphdr); 1323 1324 mss = max(tcp_mssdflt, mss); 1325 return (mss); 1326 } 1327 1328 /* 1329 * Set connection variables based on the peer's advertised MSS. 1330 * We are passed the TCPCB for the actual connection. If we 1331 * are the server, we are called by the compressed state engine 1332 * when the 3-way handshake is complete. If we are the client, 1333 * we are called when we recieve the SYN,ACK from the server. 1334 * 1335 * NOTE: Our advertised MSS value must be initialized in the TCPCB 1336 * before this routine is called! 1337 */ 1338 void 1339 tcp_mss_from_peer(tp, offer) 1340 struct tcpcb *tp; 1341 int offer; 1342 { 1343 struct socket *so; 1344 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1345 struct rtentry *rt; 1346 #endif 1347 u_long bufsize; 1348 int mss; 1349 1350 so = NULL; 1351 rt = NULL; 1352 if (tp->t_inpcb) { 1353 so = tp->t_inpcb->inp_socket; 1354 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1355 rt = in_pcbrtentry(tp->t_inpcb); 1356 #endif 1357 } 1358 #ifdef INET6 1359 else if (tp->t_in6pcb) { 1360 so = tp->t_in6pcb->in6p_socket; 1361 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1362 #ifdef TCP6 1363 rt = NULL; 1364 #else 1365 rt = in6_pcbrtentry(tp->t_in6pcb); 1366 #endif 1367 #endif 1368 } 1369 #endif 1370 1371 /* 1372 * As per RFC1122, use the default MSS value, unless they 1373 * sent us an offer. Do not accept offers less than 32 bytes. 1374 */ 1375 mss = tcp_mssdflt; 1376 if (offer) 1377 mss = offer; 1378 mss = max(mss, 32); /* sanity */ 1379 tp->t_peermss = mss; 1380 mss -= tcp_optlen(tp); 1381 if (tp->t_inpcb) 1382 mss -= ip_optlen(tp->t_inpcb); 1383 #ifdef INET6 1384 else if (tp->t_in6pcb) 1385 mss -= ip6_optlen(tp->t_in6pcb); 1386 #endif 1387 1388 /* 1389 * If there's a pipesize, change the socket buffer to that size. 1390 * Make the socket buffer an integral number of MSS units. If 1391 * the MSS is larger than the socket buffer, artificially decrease 1392 * the MSS. 1393 */ 1394 #ifdef RTV_SPIPE 1395 if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0) 1396 bufsize = rt->rt_rmx.rmx_sendpipe; 1397 else 1398 #endif 1399 bufsize = so->so_snd.sb_hiwat; 1400 if (bufsize < mss) 1401 mss = bufsize; 1402 else { 1403 bufsize = roundup(bufsize, mss); 1404 if (bufsize > sb_max) 1405 bufsize = sb_max; 1406 (void) sbreserve(&so->so_snd, bufsize); 1407 } 1408 tp->t_segsz = mss; 1409 1410 #ifdef RTV_SSTHRESH 1411 if (rt != NULL && rt->rt_rmx.rmx_ssthresh) { 1412 /* 1413 * There's some sort of gateway or interface buffer 1414 * limit on the path. Use this to set the slow 1415 * start threshold, but set the threshold to no less 1416 * than 2 * MSS. 1417 */ 1418 tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh); 1419 } 1420 #endif 1421 } 1422 1423 /* 1424 * Processing necessary when a TCP connection is established. 1425 */ 1426 void 1427 tcp_established(tp) 1428 struct tcpcb *tp; 1429 { 1430 struct socket *so; 1431 #ifdef RTV_RPIPE 1432 struct rtentry *rt; 1433 #endif 1434 u_long bufsize; 1435 1436 so = NULL; 1437 rt = NULL; 1438 if (tp->t_inpcb) { 1439 so = tp->t_inpcb->inp_socket; 1440 #if defined(RTV_RPIPE) 1441 rt = in_pcbrtentry(tp->t_inpcb); 1442 #endif 1443 } 1444 #ifdef INET6 1445 else if (tp->t_in6pcb) { 1446 so = tp->t_in6pcb->in6p_socket; 1447 #if defined(RTV_RPIPE) 1448 #ifdef TCP6 1449 rt = NULL; 1450 #else 1451 rt = in6_pcbrtentry(tp->t_in6pcb); 1452 #endif 1453 #endif 1454 } 1455 #endif 1456 1457 tp->t_state = TCPS_ESTABLISHED; 1458 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle); 1459 1460 #ifdef RTV_RPIPE 1461 if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0) 1462 bufsize = rt->rt_rmx.rmx_recvpipe; 1463 else 1464 #endif 1465 bufsize = so->so_rcv.sb_hiwat; 1466 if (bufsize > tp->t_ourmss) { 1467 bufsize = roundup(bufsize, tp->t_ourmss); 1468 if (bufsize > sb_max) 1469 bufsize = sb_max; 1470 (void) sbreserve(&so->so_rcv, bufsize); 1471 } 1472 } 1473 1474 /* 1475 * Check if there's an initial rtt or rttvar. Convert from the 1476 * route-table units to scaled multiples of the slow timeout timer. 1477 * Called only during the 3-way handshake. 1478 */ 1479 void 1480 tcp_rmx_rtt(tp) 1481 struct tcpcb *tp; 1482 { 1483 #ifdef RTV_RTT 1484 struct rtentry *rt = NULL; 1485 int rtt; 1486 1487 if (tp->t_inpcb) 1488 rt = in_pcbrtentry(tp->t_inpcb); 1489 #ifdef INET6 1490 else if (tp->t_in6pcb) { 1491 #ifdef TCP6 1492 rt = NULL; 1493 #else 1494 rt = in6_pcbrtentry(tp->t_in6pcb); 1495 #endif 1496 } 1497 #endif 1498 if (rt == NULL) 1499 return; 1500 1501 if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) { 1502 /* 1503 * XXX The lock bit for MTU indicates that the value 1504 * is also a minimum value; this is subject to time. 1505 */ 1506 if (rt->rt_rmx.rmx_locks & RTV_RTT) 1507 TCPT_RANGESET(tp->t_rttmin, 1508 rtt / (RTM_RTTUNIT / PR_SLOWHZ), 1509 TCPTV_MIN, TCPTV_REXMTMAX); 1510 tp->t_srtt = rtt / 1511 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1512 if (rt->rt_rmx.rmx_rttvar) { 1513 tp->t_rttvar = rt->rt_rmx.rmx_rttvar / 1514 ((RTM_RTTUNIT / PR_SLOWHZ) >> 1515 (TCP_RTTVAR_SHIFT + 2)); 1516 } else { 1517 /* Default variation is +- 1 rtt */ 1518 tp->t_rttvar = 1519 tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT); 1520 } 1521 TCPT_RANGESET(tp->t_rxtcur, 1522 ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2), 1523 tp->t_rttmin, TCPTV_REXMTMAX); 1524 } 1525 #endif 1526 } 1527 1528 tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */ 1529 1530 /* 1531 * Get a new sequence value given a tcp control block 1532 */ 1533 tcp_seq 1534 tcp_new_iss(tp, len, addin) 1535 void *tp; 1536 u_long len; 1537 tcp_seq addin; 1538 { 1539 tcp_seq tcp_iss; 1540 1541 /* 1542 * Randomize. 1543 */ 1544 #if NRND > 0 1545 rnd_extract_data(&tcp_iss, sizeof(tcp_iss), RND_EXTRACT_ANY); 1546 #else 1547 tcp_iss = random(); 1548 #endif 1549 1550 /* 1551 * If we were asked to add some amount to a known value, 1552 * we will take a random value obtained above, mask off the upper 1553 * bits, and add in the known value. We also add in a constant to 1554 * ensure that we are at least a certain distance from the original 1555 * value. 1556 * 1557 * This is used when an old connection is in timed wait 1558 * and we have a new one coming in, for instance. 1559 */ 1560 if (addin != 0) { 1561 #ifdef TCPISS_DEBUG 1562 printf("Random %08x, ", tcp_iss); 1563 #endif 1564 tcp_iss &= TCP_ISS_RANDOM_MASK; 1565 tcp_iss += addin + TCP_ISSINCR; 1566 #ifdef TCPISS_DEBUG 1567 printf("Old ISS %08x, ISS %08x\n", addin, tcp_iss); 1568 #endif 1569 } else { 1570 tcp_iss &= TCP_ISS_RANDOM_MASK; 1571 tcp_iss += tcp_iss_seq; 1572 tcp_iss_seq += TCP_ISSINCR; 1573 #ifdef TCPISS_DEBUG 1574 printf("ISS %08x\n", tcp_iss); 1575 #endif 1576 } 1577 1578 if (tcp_compat_42) { 1579 /* 1580 * Limit it to the positive range for really old TCP 1581 * implementations. 1582 */ 1583 if (tcp_iss >= 0x80000000) 1584 tcp_iss &= 0x7fffffff; /* XXX */ 1585 } 1586 1587 return tcp_iss; 1588 } 1589 1590 #ifdef IPSEC 1591 /* compute ESP/AH header size for TCP, including outer IP header. */ 1592 size_t 1593 ipsec4_hdrsiz_tcp(tp) 1594 struct tcpcb *tp; 1595 { 1596 struct inpcb *inp; 1597 size_t hdrsiz; 1598 1599 /* XXX mapped addr case (tp->t_in6pcb) */ 1600 if (!tp || !tp->t_template || !(inp = tp->t_inpcb)) 1601 return 0; 1602 switch (tp->t_family) { 1603 case AF_INET: 1604 hdrsiz = ipsec4_hdrsiz(tp->t_template, inp); 1605 break; 1606 default: 1607 hdrsiz = 0; 1608 break; 1609 } 1610 1611 return hdrsiz; 1612 } 1613 1614 #if defined(INET6) && !defined(TCP6) 1615 size_t 1616 ipsec6_hdrsiz_tcp(tp) 1617 struct tcpcb *tp; 1618 { 1619 struct in6pcb *in6p; 1620 size_t hdrsiz; 1621 1622 if (!tp || !tp->t_template || !(in6p = tp->t_in6pcb)) 1623 return 0; 1624 switch (tp->t_family) { 1625 case AF_INET6: 1626 hdrsiz = ipsec6_hdrsiz(tp->t_template, in6p); 1627 break; 1628 case AF_INET: 1629 /* mapped address case - tricky */ 1630 default: 1631 hdrsiz = 0; 1632 break; 1633 } 1634 1635 return hdrsiz; 1636 } 1637 #endif 1638 #endif /*IPSEC*/ 1639 1640 /* 1641 * Determine the length of the TCP options for this connection. 1642 * 1643 * XXX: What do we do for SACK, when we add that? Just reserve 1644 * all of the space? Otherwise we can't exactly be incrementing 1645 * cwnd by an amount that varies depending on the amount we last 1646 * had to SACK! 1647 */ 1648 1649 u_int 1650 tcp_optlen(tp) 1651 struct tcpcb *tp; 1652 { 1653 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 1654 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1655 return TCPOLEN_TSTAMP_APPA; 1656 else 1657 return 0; 1658 } 1659
Indexes created Tue Sep 23 14:10:03 GMT 2025