1 /* $NetBSD: tcp_subr.c,v 1.85 1999/12/15 06:28:43 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 #include <netinet6/ip6protosw.h> 143 #endif 144 145 #include <netinet/tcp.h> 146 #include <netinet/tcp_fsm.h> 147 #include <netinet/tcp_seq.h> 148 #include <netinet/tcp_timer.h> 149 #include <netinet/tcp_var.h> 150 #include <netinet/tcpip.h> 151 152 #ifdef IPSEC 153 #include <netinet6/ipsec.h> 154 #endif /*IPSEC*/ 155 156 #ifdef INET6 157 struct in6pcb tcb6; 158 #endif 159 160 /* patchable/settable parameters for tcp */ 161 int tcp_mssdflt = TCP_MSS; 162 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 163 int tcp_do_rfc1323 = 1; /* window scaling / timestamps (obsolete) */ 164 int tcp_do_sack = 1; /* selective acknowledgement */ 165 int tcp_do_win_scale = 1; /* RFC1323 window scaling */ 166 int tcp_do_timestamps = 1; /* RFC1323 timestamps */ 167 int tcp_do_newreno = 0; /* Use the New Reno algorithms */ 168 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ 169 int tcp_init_win = 1; 170 int tcp_mss_ifmtu = 0; 171 #ifdef TCP_COMPAT_42 172 int tcp_compat_42 = 1; 173 #else 174 int tcp_compat_42 = 0; 175 #endif 176 177 #ifndef TCBHASHSIZE 178 #define TCBHASHSIZE 128 179 #endif 180 int tcbhashsize = TCBHASHSIZE; 181 182 int tcp_freeq __P((struct tcpcb *)); 183 184 struct pool tcpcb_pool; 185 186 /* 187 * Tcp initialization 188 */ 189 void 190 tcp_init() 191 { 192 int hlen; 193 194 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl", 195 0, NULL, NULL, M_PCB); 196 in_pcbinit(&tcbtable, tcbhashsize, tcbhashsize); 197 #ifdef INET6 198 tcb6.in6p_next = tcb6.in6p_prev = &tcb6; 199 #endif 200 LIST_INIT(&tcp_delacks); 201 202 hlen = sizeof(struct ip) + sizeof(struct tcphdr); 203 #ifdef INET6 204 if (sizeof(struct ip) < sizeof(struct ip6_hdr)) 205 hlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 206 #endif 207 if (max_protohdr < hlen) 208 max_protohdr = hlen; 209 if (max_linkhdr + hlen > MHLEN) 210 panic("tcp_init"); 211 212 /* Initialize the compressed state engine. */ 213 syn_cache_init(); 214 } 215 216 /* 217 * Create template to be used to send tcp packets on a connection. 218 * Call after host entry created, allocates an mbuf and fills 219 * in a skeletal tcp/ip header, minimizing the amount of work 220 * necessary when the connection is used. 221 */ 222 struct mbuf * 223 tcp_template(tp) 224 struct tcpcb *tp; 225 { 226 register struct inpcb *inp = tp->t_inpcb; 227 #ifdef INET6 228 register struct in6pcb *in6p = tp->t_in6pcb; 229 #endif 230 register struct tcphdr *n; 231 register struct mbuf *m; 232 int hlen; 233 234 switch (tp->t_family) { 235 case AF_INET: 236 hlen = sizeof(struct ip); 237 if (inp) 238 break; 239 #ifdef INET6 240 if (in6p) { 241 /* mapped addr case */ 242 if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_laddr) 243 && IN6_IS_ADDR_V4MAPPED(&in6p->in6p_faddr)) 244 break; 245 } 246 #endif 247 return NULL; /*EINVAL*/ 248 #ifdef INET6 249 case AF_INET6: 250 hlen = sizeof(struct ip6_hdr); 251 if (in6p) { 252 /* more sainty check? */ 253 break; 254 } 255 return NULL; /*EINVAL*/ 256 #endif 257 default: 258 hlen = 0; /*pacify gcc*/ 259 return NULL; /*EAFNOSUPPORT*/ 260 } 261 if ((m = tp->t_template) == 0) { 262 MGETHDR(m, M_DONTWAIT, MT_HEADER); 263 if (m) { 264 MCLGET(m, M_DONTWAIT); 265 if ((m->m_flags & M_EXT) == 0) { 266 m_free(m); 267 m = NULL; 268 } 269 } 270 if (m == NULL) 271 return NULL; 272 m->m_pkthdr.len = m->m_len = hlen + sizeof(struct tcphdr); 273 } 274 bzero(mtod(m, caddr_t), m->m_len); 275 switch (tp->t_family) { 276 case AF_INET: 277 { 278 struct ipovly *ipov; 279 mtod(m, struct ip *)->ip_v = 4; 280 ipov = mtod(m, struct ipovly *); 281 ipov->ih_pr = IPPROTO_TCP; 282 ipov->ih_len = htons(sizeof(struct tcphdr)); 283 if (inp) { 284 ipov->ih_src = inp->inp_laddr; 285 ipov->ih_dst = inp->inp_faddr; 286 } 287 #ifdef INET6 288 else if (in6p) { 289 /* mapped addr case */ 290 bcopy(&in6p->in6p_laddr.s6_addr32[3], &ipov->ih_src, 291 sizeof(ipov->ih_src)); 292 bcopy(&in6p->in6p_faddr.s6_addr32[3], &ipov->ih_dst, 293 sizeof(ipov->ih_dst)); 294 } 295 #endif 296 break; 297 } 298 #ifdef INET6 299 case AF_INET6: 300 { 301 struct ip6_hdr *ip6; 302 mtod(m, struct ip *)->ip_v = 6; 303 ip6 = mtod(m, struct ip6_hdr *); 304 ip6->ip6_nxt = IPPROTO_TCP; 305 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 306 ip6->ip6_src = in6p->in6p_laddr; 307 ip6->ip6_dst = in6p->in6p_faddr; 308 ip6->ip6_flow = in6p->in6p_flowinfo & IPV6_FLOWINFO_MASK; 309 if (ip6_auto_flowlabel) { 310 ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK; 311 ip6->ip6_flow |= 312 (htonl(ip6_flow_seq++) & IPV6_FLOWLABEL_MASK); 313 } 314 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 315 ip6->ip6_vfc |= IPV6_VERSION; 316 break; 317 } 318 #endif 319 } 320 n = (struct tcphdr *)(mtod(m, caddr_t) + hlen); 321 if (inp) { 322 n->th_sport = inp->inp_lport; 323 n->th_dport = inp->inp_fport; 324 } 325 #ifdef INET6 326 else if (in6p) { 327 n->th_sport = in6p->in6p_lport; 328 n->th_dport = in6p->in6p_fport; 329 } 330 #endif 331 n->th_seq = 0; 332 n->th_ack = 0; 333 n->th_x2 = 0; 334 n->th_off = 5; 335 n->th_flags = 0; 336 n->th_win = 0; 337 n->th_sum = 0; 338 n->th_urp = 0; 339 return (m); 340 } 341 342 /* 343 * Send a single message to the TCP at address specified by 344 * the given TCP/IP header. If m == 0, then we make a copy 345 * of the tcpiphdr at ti and send directly to the addressed host. 346 * This is used to force keep alive messages out using the TCP 347 * template for a connection tp->t_template. If flags are given 348 * then we send a message back to the TCP which originated the 349 * segment ti, and discard the mbuf containing it and any other 350 * attached mbufs. 351 * 352 * In any case the ack and sequence number of the transmitted 353 * segment are as specified by the parameters. 354 */ 355 int 356 tcp_respond(tp, template, m, th0, ack, seq, flags) 357 struct tcpcb *tp; 358 struct mbuf *template; 359 register struct mbuf *m; 360 struct tcphdr *th0; 361 tcp_seq ack, seq; 362 int flags; 363 { 364 #ifndef INET6 365 struct route iproute; 366 #else 367 struct route_in6 iproute; /* sizeof(route_in6) > sizeof(route) */ 368 #endif 369 struct route *ro; 370 struct rtentry *rt; 371 int error, tlen, win = 0; 372 int hlen; 373 struct ip *ip; 374 #ifdef INET6 375 struct ip6_hdr *ip6; 376 #endif 377 int family; /* family on packet, not inpcb/in6pcb! */ 378 struct tcphdr *th; 379 380 if (tp != NULL && (flags & TH_RST) == 0) { 381 if (tp->t_inpcb) 382 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 383 #ifdef INET6 384 else if (tp->t_in6pcb) 385 win = sbspace(&tp->t_in6pcb->in6p_socket->so_rcv); 386 #endif 387 } 388 389 ip = NULL; 390 #ifdef INET6 391 ip6 = NULL; 392 #endif 393 if (m == 0) { 394 if (!template) 395 return EINVAL; 396 397 /* get family information from template */ 398 switch (mtod(template, struct ip *)->ip_v) { 399 case 4: 400 family = AF_INET; 401 hlen = sizeof(struct ip); 402 break; 403 #ifdef INET6 404 case 6: 405 family = AF_INET6; 406 hlen = sizeof(struct ip6_hdr); 407 break; 408 #endif 409 default: 410 return EAFNOSUPPORT; 411 } 412 413 MGETHDR(m, M_DONTWAIT, MT_HEADER); 414 if (m) { 415 MCLGET(m, M_DONTWAIT); 416 if ((m->m_flags & M_EXT) == 0) { 417 m_free(m); 418 m = NULL; 419 } 420 } 421 if (m == NULL) 422 return (ENOBUFS); 423 424 if (tcp_compat_42) 425 tlen = 1; 426 else 427 tlen = 0; 428 429 m->m_data += max_linkhdr; 430 bcopy(mtod(template, caddr_t), mtod(m, caddr_t), 431 template->m_len); 432 switch (family) { 433 case AF_INET: 434 ip = mtod(m, struct ip *); 435 th = (struct tcphdr *)(ip + 1); 436 break; 437 #ifdef INET6 438 case AF_INET6: 439 ip6 = mtod(m, struct ip6_hdr *); 440 th = (struct tcphdr *)(ip6 + 1); 441 break; 442 #endif 443 #if 0 444 default: 445 /* noone will visit here */ 446 m_freem(m); 447 return EAFNOSUPPORT; 448 #endif 449 } 450 flags = TH_ACK; 451 } else { 452 /* get family information from m */ 453 switch (mtod(m, struct ip *)->ip_v) { 454 case 4: 455 family = AF_INET; 456 hlen = sizeof(struct ip); 457 break; 458 #ifdef INET6 459 case 6: 460 family = AF_INET6; 461 hlen = sizeof(struct ip6_hdr); 462 break; 463 #endif 464 default: 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 if (tp && tp->t_in6pcb) { 540 struct ifnet *oifp; 541 ro = (struct route *)&tp->t_in6pcb->in6p_route; 542 oifp = ro->ro_rt ? ro->ro_rt->rt_ifp : NULL; 543 ip6->ip6_hlim = in6_selecthlim(tp->t_in6pcb, oifp); 544 } else 545 ip6->ip6_hlim = ip6_defhlim; 546 ip6->ip6_flow &= ~IPV6_FLOWINFO_MASK; 547 if (ip6_auto_flowlabel) { 548 ip6->ip6_flow |= 549 (htonl(ip6_flow_seq++) & IPV6_FLOWLABEL_MASK); 550 } 551 break; 552 } 553 #endif 554 } 555 556 #ifdef IPSEC 557 m->m_pkthdr.rcvif = NULL; 558 #endif /*IPSEC*/ 559 560 /* 561 * If we're doing Path MTU discovery, we need to set DF unless 562 * the route's MTU is locked. If we lack a route, we need to 563 * look it up now. 564 * 565 * ip_output() could do this for us, but it's convenient to just 566 * do it here unconditionally. 567 */ 568 if (tp != NULL && tp->t_inpcb != NULL) { 569 ro = &tp->t_inpcb->inp_route; 570 #ifdef IPSEC 571 m->m_pkthdr.rcvif = (struct ifnet *)tp->t_inpcb->inp_socket; 572 #endif 573 #ifdef DIAGNOSTIC 574 if (family != AF_INET) 575 panic("tcp_respond: address family mismatch"); 576 if (!in_hosteq(ip->ip_dst, tp->t_inpcb->inp_faddr)) { 577 panic("tcp_respond: ip_dst %x != inp_faddr %x", 578 ntohl(ip->ip_dst.s_addr), 579 ntohl(tp->t_inpcb->inp_faddr.s_addr)); 580 } 581 #endif 582 } 583 #ifdef INET6 584 else if (tp != NULL && tp->t_in6pcb != NULL) { 585 ro = (struct route *)&tp->t_in6pcb->in6p_route; 586 #ifdef IPSEC 587 m->m_pkthdr.rcvif = (struct ifnet *)tp->t_in6pcb->in6p_socket; 588 #endif 589 #ifdef DIAGNOSTIC 590 if (family == AF_INET) { 591 if (!IN6_IS_ADDR_V4MAPPED(&tp->t_in6pcb->in6p_faddr)) 592 panic("tcp_respond: not mapped addr"); 593 if (bcmp(&ip->ip_dst, 594 &tp->t_in6pcb->in6p_faddr.s6_addr32[3], 595 sizeof(ip->ip_dst)) != 0) { 596 panic("tcp_respond: ip_dst != in6p_faddr"); 597 } 598 } else if (family == AF_INET6) { 599 if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &tp->t_in6pcb->in6p_faddr)) 600 panic("tcp_respond: ip6_dst != in6p_faddr"); 601 } else 602 panic("tcp_respond: address family mismatch"); 603 #endif 604 } 605 #endif 606 else { 607 ro = (struct route *)&iproute; 608 bzero(ro, sizeof(iproute)); 609 } 610 if ((rt = ro->ro_rt) == NULL || (rt->rt_flags & RTF_UP) == 0) { 611 if (ro->ro_rt != NULL) { 612 RTFREE(ro->ro_rt); 613 ro->ro_rt = NULL; 614 } 615 switch (family) { 616 case AF_INET: 617 { 618 struct sockaddr_in *dst; 619 dst = satosin(&ro->ro_dst); 620 dst->sin_family = AF_INET; 621 dst->sin_len = sizeof(*dst); 622 dst->sin_addr = ip->ip_dst; 623 break; 624 } 625 #ifdef INET6 626 case AF_INET6: 627 { 628 struct sockaddr_in6 *dst; 629 dst = satosin6(&ro->ro_dst); 630 bzero(dst, sizeof(*dst)); 631 dst->sin6_family = AF_INET6; 632 dst->sin6_len = sizeof(*dst); 633 dst->sin6_addr = ip6->ip6_dst; 634 break; 635 } 636 #endif 637 } 638 rtalloc(ro); 639 if ((rt = ro->ro_rt) == NULL) { 640 m_freem(m); 641 switch (family) { 642 case AF_INET: 643 ipstat.ips_noroute++; 644 break; 645 #ifdef INET6 646 case AF_INET6: 647 ip6stat.ip6s_noroute++; 648 break; 649 #endif 650 } 651 return (EHOSTUNREACH); 652 } 653 } 654 switch (family) { 655 case AF_INET: 656 if (ip_mtudisc != 0 && (rt->rt_rmx.rmx_locks & RTV_MTU) == 0) 657 ip->ip_off |= IP_DF; 658 659 error = ip_output(m, NULL, ro, 0, NULL); 660 break; 661 #ifdef INET6 662 case AF_INET6: 663 error = ip6_output(m, NULL, (struct route_in6 *)ro, 0, NULL, 664 NULL); 665 break; 666 #endif 667 default: 668 error = EAFNOSUPPORT; 669 break; 670 } 671 672 if (ro == (struct route *)&iproute) { 673 RTFREE(ro->ro_rt); 674 ro->ro_rt = NULL; 675 } 676 677 return (error); 678 } 679 680 /* 681 * Create a new TCP control block, making an 682 * empty reassembly queue and hooking it to the argument 683 * protocol control block. 684 */ 685 struct tcpcb * 686 tcp_newtcpcb(family, aux) 687 int family; /* selects inpcb, or in6pcb */ 688 void *aux; 689 { 690 register struct tcpcb *tp; 691 692 switch (family) { 693 case PF_INET: 694 break; 695 #ifdef INET6 696 case PF_INET6: 697 break; 698 #endif 699 default: 700 return NULL; 701 } 702 703 tp = pool_get(&tcpcb_pool, PR_NOWAIT); 704 if (tp == NULL) 705 return (NULL); 706 bzero((caddr_t)tp, sizeof(struct tcpcb)); 707 LIST_INIT(&tp->segq); 708 LIST_INIT(&tp->timeq); 709 tp->t_family = family; /* may be overridden later on */ 710 tp->t_peermss = tcp_mssdflt; 711 tp->t_ourmss = tcp_mssdflt; 712 tp->t_segsz = tcp_mssdflt; 713 LIST_INIT(&tp->t_sc); 714 715 tp->t_flags = 0; 716 if (tcp_do_rfc1323 && tcp_do_win_scale) 717 tp->t_flags |= TF_REQ_SCALE; 718 if (tcp_do_rfc1323 && tcp_do_timestamps) 719 tp->t_flags |= TF_REQ_TSTMP; 720 if (tcp_do_sack == 2) 721 tp->t_flags |= TF_WILL_SACK; 722 else if (tcp_do_sack == 1) 723 tp->t_flags |= TF_WILL_SACK|TF_IGNR_RXSACK; 724 tp->t_flags |= TF_CANT_TXSACK; 725 switch (family) { 726 case PF_INET: 727 tp->t_inpcb = (struct inpcb *)aux; 728 break; 729 #ifdef INET6 730 case PF_INET6: 731 tp->t_in6pcb = (struct in6pcb *)aux; 732 break; 733 #endif 734 } 735 /* 736 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 737 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 738 * reasonable initial retransmit time. 739 */ 740 tp->t_srtt = TCPTV_SRTTBASE; 741 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1); 742 tp->t_rttmin = TCPTV_MIN; 743 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 744 TCPTV_MIN, TCPTV_REXMTMAX); 745 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 746 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 747 if (family == AF_INET) { 748 struct inpcb *inp = (struct inpcb *)aux; 749 inp->inp_ip.ip_ttl = ip_defttl; 750 inp->inp_ppcb = (caddr_t)tp; 751 } 752 #ifdef INET6 753 else if (family == AF_INET6) { 754 struct in6pcb *in6p = (struct in6pcb *)aux; 755 in6p->in6p_ip6.ip6_hlim = in6_selecthlim(in6p, 756 in6p->in6p_route.ro_rt ? in6p->in6p_route.ro_rt->rt_ifp 757 : NULL); 758 in6p->in6p_ppcb = (caddr_t)tp; 759 } 760 #endif 761 return (tp); 762 } 763 764 /* 765 * Drop a TCP connection, reporting 766 * the specified error. If connection is synchronized, 767 * then send a RST to peer. 768 */ 769 struct tcpcb * 770 tcp_drop(tp, errno) 771 register struct tcpcb *tp; 772 int errno; 773 { 774 struct socket *so; 775 776 if (tp->t_inpcb) 777 so = tp->t_inpcb->inp_socket; 778 #ifdef INET6 779 else if (tp->t_in6pcb) 780 so = tp->t_in6pcb->in6p_socket; 781 #endif 782 else 783 return NULL; 784 785 if (TCPS_HAVERCVDSYN(tp->t_state)) { 786 tp->t_state = TCPS_CLOSED; 787 (void) tcp_output(tp); 788 tcpstat.tcps_drops++; 789 } else 790 tcpstat.tcps_conndrops++; 791 if (errno == ETIMEDOUT && tp->t_softerror) 792 errno = tp->t_softerror; 793 so->so_error = errno; 794 return (tcp_close(tp)); 795 } 796 797 /* 798 * Close a TCP control block: 799 * discard all space held by the tcp 800 * discard internet protocol block 801 * wake up any sleepers 802 */ 803 struct tcpcb * 804 tcp_close(tp) 805 register struct tcpcb *tp; 806 { 807 struct inpcb *inp; 808 #ifdef INET6 809 struct in6pcb *in6p; 810 #endif 811 struct socket *so; 812 #ifdef RTV_RTT 813 register struct rtentry *rt; 814 #endif 815 struct route *ro; 816 817 inp = tp->t_inpcb; 818 #ifdef INET6 819 in6p = tp->t_in6pcb; 820 #endif 821 so = NULL; 822 ro = NULL; 823 if (inp) { 824 so = inp->inp_socket; 825 ro = &inp->inp_route; 826 } 827 #ifdef INET6 828 else if (in6p) { 829 so = in6p->in6p_socket; 830 ro = (struct route *)&in6p->in6p_route; 831 } 832 #endif 833 834 #ifdef RTV_RTT 835 /* 836 * If we sent enough data to get some meaningful characteristics, 837 * save them in the routing entry. 'Enough' is arbitrarily 838 * defined as the sendpipesize (default 4K) * 16. This would 839 * give us 16 rtt samples assuming we only get one sample per 840 * window (the usual case on a long haul net). 16 samples is 841 * enough for the srtt filter to converge to within 5% of the correct 842 * value; fewer samples and we could save a very bogus rtt. 843 * 844 * Don't update the default route's characteristics and don't 845 * update anything that the user "locked". 846 */ 847 if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) && 848 ro && (rt = ro->ro_rt) && 849 !in_nullhost(satosin(rt_key(rt))->sin_addr)) { 850 register u_long i = 0; 851 852 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 853 i = tp->t_srtt * 854 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 855 if (rt->rt_rmx.rmx_rtt && i) 856 /* 857 * filter this update to half the old & half 858 * the new values, converting scale. 859 * See route.h and tcp_var.h for a 860 * description of the scaling constants. 861 */ 862 rt->rt_rmx.rmx_rtt = 863 (rt->rt_rmx.rmx_rtt + i) / 2; 864 else 865 rt->rt_rmx.rmx_rtt = i; 866 } 867 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 868 i = tp->t_rttvar * 869 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2)); 870 if (rt->rt_rmx.rmx_rttvar && i) 871 rt->rt_rmx.rmx_rttvar = 872 (rt->rt_rmx.rmx_rttvar + i) / 2; 873 else 874 rt->rt_rmx.rmx_rttvar = i; 875 } 876 /* 877 * update the pipelimit (ssthresh) if it has been updated 878 * already or if a pipesize was specified & the threshhold 879 * got below half the pipesize. I.e., wait for bad news 880 * before we start updating, then update on both good 881 * and bad news. 882 */ 883 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 884 (i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) || 885 i < (rt->rt_rmx.rmx_sendpipe / 2)) { 886 /* 887 * convert the limit from user data bytes to 888 * packets then to packet data bytes. 889 */ 890 i = (i + tp->t_segsz / 2) / tp->t_segsz; 891 if (i < 2) 892 i = 2; 893 i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr)); 894 if (rt->rt_rmx.rmx_ssthresh) 895 rt->rt_rmx.rmx_ssthresh = 896 (rt->rt_rmx.rmx_ssthresh + i) / 2; 897 else 898 rt->rt_rmx.rmx_ssthresh = i; 899 } 900 } 901 #endif /* RTV_RTT */ 902 /* free the reassembly queue, if any */ 903 TCP_REASS_LOCK(tp); 904 (void) tcp_freeq(tp); 905 TCP_REASS_UNLOCK(tp); 906 907 TCP_CLEAR_DELACK(tp); 908 syn_cache_cleanup(tp); 909 910 if (tp->t_template) { 911 m_free(tp->t_template); 912 tp->t_template = NULL; 913 } 914 pool_put(&tcpcb_pool, tp); 915 if (inp) { 916 inp->inp_ppcb = 0; 917 soisdisconnected(so); 918 in_pcbdetach(inp); 919 } 920 #ifdef INET6 921 else if (in6p) { 922 in6p->in6p_ppcb = 0; 923 soisdisconnected(so); 924 in6_pcbdetach(in6p); 925 } 926 #endif 927 tcpstat.tcps_closed++; 928 return ((struct tcpcb *)0); 929 } 930 931 int 932 tcp_freeq(tp) 933 struct tcpcb *tp; 934 { 935 register struct ipqent *qe; 936 int rv = 0; 937 #ifdef TCPREASS_DEBUG 938 int i = 0; 939 #endif 940 941 TCP_REASS_LOCK_CHECK(tp); 942 943 while ((qe = tp->segq.lh_first) != NULL) { 944 #ifdef TCPREASS_DEBUG 945 printf("tcp_freeq[%p,%d]: %u:%u(%u) 0x%02x\n", 946 tp, i++, qe->ipqe_seq, qe->ipqe_seq + qe->ipqe_len, 947 qe->ipqe_len, qe->ipqe_flags & (TH_SYN|TH_FIN|TH_RST)); 948 #endif 949 LIST_REMOVE(qe, ipqe_q); 950 LIST_REMOVE(qe, ipqe_timeq); 951 m_freem(qe->ipqe_m); 952 pool_put(&ipqent_pool, qe); 953 rv = 1; 954 } 955 return (rv); 956 } 957 958 /* 959 * Protocol drain routine. Called when memory is in short supply. 960 */ 961 void 962 tcp_drain() 963 { 964 register struct inpcb *inp; 965 register struct tcpcb *tp; 966 967 /* 968 * Free the sequence queue of all TCP connections. 969 */ 970 inp = tcbtable.inpt_queue.cqh_first; 971 if (inp) /* XXX */ 972 for (; inp != (struct inpcb *)&tcbtable.inpt_queue; 973 inp = inp->inp_queue.cqe_next) { 974 if ((tp = intotcpcb(inp)) != NULL) { 975 /* 976 * We may be called from a device's interrupt 977 * context. If the tcpcb is already busy, 978 * just bail out now. 979 */ 980 if (tcp_reass_lock_try(tp) == 0) 981 continue; 982 if (tcp_freeq(tp)) 983 tcpstat.tcps_connsdrained++; 984 TCP_REASS_UNLOCK(tp); 985 } 986 } 987 } 988 989 /* 990 * Notify a tcp user of an asynchronous error; 991 * store error as soft error, but wake up user 992 * (for now, won't do anything until can select for soft error). 993 */ 994 void 995 tcp_notify(inp, error) 996 struct inpcb *inp; 997 int error; 998 { 999 register struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 1000 register struct socket *so = inp->inp_socket; 1001 1002 /* 1003 * Ignore some errors if we are hooked up. 1004 * If connection hasn't completed, has retransmitted several times, 1005 * and receives a second error, give up now. This is better 1006 * than waiting a long time to establish a connection that 1007 * can never complete. 1008 */ 1009 if (tp->t_state == TCPS_ESTABLISHED && 1010 (error == EHOSTUNREACH || error == ENETUNREACH || 1011 error == EHOSTDOWN)) { 1012 return; 1013 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1014 tp->t_rxtshift > 3 && tp->t_softerror) 1015 so->so_error = error; 1016 else 1017 tp->t_softerror = error; 1018 wakeup((caddr_t) &so->so_timeo); 1019 sorwakeup(so); 1020 sowwakeup(so); 1021 } 1022 1023 #if defined(INET6) && !defined(TCP6) 1024 void 1025 tcp6_notify(in6p, error) 1026 struct in6pcb *in6p; 1027 int error; 1028 { 1029 register struct tcpcb *tp = (struct tcpcb *)in6p->in6p_ppcb; 1030 register struct socket *so = in6p->in6p_socket; 1031 1032 /* 1033 * Ignore some errors if we are hooked up. 1034 * If connection hasn't completed, has retransmitted several times, 1035 * and receives a second error, give up now. This is better 1036 * than waiting a long time to establish a connection that 1037 * can never complete. 1038 */ 1039 if (tp->t_state == TCPS_ESTABLISHED && 1040 (error == EHOSTUNREACH || error == ENETUNREACH || 1041 error == EHOSTDOWN)) { 1042 return; 1043 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1044 tp->t_rxtshift > 3 && tp->t_softerror) 1045 so->so_error = error; 1046 else 1047 tp->t_softerror = error; 1048 wakeup((caddr_t) &so->so_timeo); 1049 sorwakeup(so); 1050 sowwakeup(so); 1051 } 1052 #endif 1053 1054 #if defined(INET6) && !defined(TCP6) 1055 void 1056 tcp6_ctlinput(cmd, sa, d) 1057 int cmd; 1058 struct sockaddr *sa; 1059 void *d; 1060 { 1061 register struct tcphdr *thp; 1062 struct tcphdr th; 1063 void (*notify) __P((struct in6pcb *, int)) = tcp6_notify; 1064 int nmatch; 1065 extern struct in6_addr zeroin6_addr; /* netinet6/in6_pcb.c */ 1066 struct sockaddr_in6 sa6; 1067 register struct ip6_hdr *ip6; 1068 struct mbuf *m; 1069 int off; 1070 1071 if (sa->sa_family != AF_INET6 || 1072 sa->sa_len != sizeof(struct sockaddr_in6)) 1073 return; 1074 if ((unsigned)cmd >= PRC_NCMDS) 1075 return; 1076 else if (cmd == PRC_QUENCH) { 1077 /* XXX there's no PRC_QUENCH in IPv6 */ 1078 notify = tcp6_quench; 1079 } else if (PRC_IS_REDIRECT(cmd)) 1080 notify = in6_rtchange, d = NULL; 1081 else if (cmd == PRC_MSGSIZE) 1082 notify = tcp6_mtudisc, d = NULL; 1083 else if (cmd == PRC_HOSTDEAD) 1084 d = NULL; 1085 else if (inet6ctlerrmap[cmd] == 0) 1086 return; 1087 1088 /* translate addresses into internal form */ 1089 sa6 = *(struct sockaddr_in6 *)sa; 1090 if (IN6_IS_ADDR_LINKLOCAL(&sa6.sin6_addr)) 1091 sa6.sin6_addr.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 1092 1093 /* if the parameter is from icmp6, decode it. */ 1094 if (d != NULL) { 1095 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 1096 m = ip6cp->ip6c_m; 1097 ip6 = ip6cp->ip6c_ip6; 1098 off = ip6cp->ip6c_off; 1099 } else { 1100 m = NULL; 1101 ip6 = NULL; 1102 } 1103 1104 if (ip6) { 1105 /* 1106 * XXX: We assume that when ip6 is non NULL, 1107 * M and OFF are valid. 1108 */ 1109 struct in6_addr s; 1110 1111 /* translate addresses into internal form */ 1112 memcpy(&s, &ip6->ip6_src, sizeof(s)); 1113 if (IN6_IS_ADDR_LINKLOCAL(&s)) 1114 s.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 1115 1116 if (m->m_len < off + sizeof(th)) { 1117 /* 1118 * this should be rare case, 1119 * so we compromise on this copy... 1120 */ 1121 m_copydata(m, off, sizeof(th), (caddr_t)&th); 1122 thp = &th; 1123 } else 1124 thp = (struct tcphdr *)(mtod(m, caddr_t) + off); 1125 nmatch = in6_pcbnotify(&tcb6, (struct sockaddr *)&sa6, 1126 thp->th_dport, &s, thp->th_sport, cmd, notify); 1127 if (nmatch == 0 && syn_cache_count && 1128 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 1129 inet6ctlerrmap[cmd] == ENETUNREACH || 1130 inet6ctlerrmap[cmd] == EHOSTDOWN)) { 1131 struct sockaddr_in6 sin6; 1132 bzero(&sin6, sizeof(sin6)); 1133 sin6.sin6_len = sizeof(sin6); 1134 sin6.sin6_family = AF_INET6; 1135 sin6.sin6_port = thp->th_sport; 1136 sin6.sin6_addr = s; 1137 syn_cache_unreach((struct sockaddr *)&sin6, sa, thp); 1138 } 1139 } else { 1140 (void) in6_pcbnotify(&tcb6, (struct sockaddr *)&sa6, 0, 1141 &zeroin6_addr, 0, cmd, notify); 1142 } 1143 } 1144 #endif 1145 1146 /* assumes that ip header and tcp header are contiguous on mbuf */ 1147 void * 1148 tcp_ctlinput(cmd, sa, v) 1149 int cmd; 1150 struct sockaddr *sa; 1151 register void *v; 1152 { 1153 register struct ip *ip = v; 1154 register struct tcphdr *th; 1155 extern int inetctlerrmap[]; 1156 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1157 int errno; 1158 int nmatch; 1159 1160 if (sa->sa_family != AF_INET || 1161 sa->sa_len != sizeof(struct sockaddr_in)) 1162 return NULL; 1163 if ((unsigned)cmd >= PRC_NCMDS) 1164 return NULL; 1165 errno = inetctlerrmap[cmd]; 1166 if (cmd == PRC_QUENCH) 1167 notify = tcp_quench; 1168 else if (PRC_IS_REDIRECT(cmd)) 1169 notify = in_rtchange, ip = 0; 1170 else if (cmd == PRC_MSGSIZE && ip_mtudisc) 1171 notify = tcp_mtudisc, ip = 0; 1172 else if (cmd == PRC_HOSTDEAD) 1173 ip = 0; 1174 else if (errno == 0) 1175 return NULL; 1176 if (ip && ip->ip_v == 4 && sa->sa_family == AF_INET) { 1177 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1178 nmatch = in_pcbnotify(&tcbtable, satosin(sa)->sin_addr, 1179 th->th_dport, ip->ip_src, th->th_sport, errno, notify); 1180 if (nmatch == 0 && syn_cache_count && 1181 (inetctlerrmap[cmd] == EHOSTUNREACH || 1182 inetctlerrmap[cmd] == ENETUNREACH || 1183 inetctlerrmap[cmd] == EHOSTDOWN)) { 1184 struct sockaddr_in sin; 1185 bzero(&sin, sizeof(sin)); 1186 sin.sin_len = sizeof(sin); 1187 sin.sin_family = AF_INET; 1188 sin.sin_port = th->th_sport; 1189 sin.sin_addr = ip->ip_src; 1190 syn_cache_unreach((struct sockaddr *)&sin, sa, th); 1191 } 1192 1193 /* XXX mapped address case */ 1194 } 1195 else { 1196 (void)in_pcbnotifyall(&tcbtable, satosin(sa)->sin_addr, errno, 1197 notify); 1198 } 1199 return NULL; 1200 } 1201 1202 /* 1203 * When a source quence is received, we are being notifed of congestion. 1204 * Close the congestion window down to the Loss Window (one segment). 1205 * We will gradually open it again as we proceed. 1206 */ 1207 void 1208 tcp_quench(inp, errno) 1209 struct inpcb *inp; 1210 int errno; 1211 { 1212 struct tcpcb *tp = intotcpcb(inp); 1213 1214 if (tp) 1215 tp->snd_cwnd = tp->t_segsz; 1216 } 1217 1218 #if defined(INET6) && !defined(TCP6) 1219 void 1220 tcp6_quench(in6p, errno) 1221 struct in6pcb *in6p; 1222 int errno; 1223 { 1224 struct tcpcb *tp = in6totcpcb(in6p); 1225 1226 if (tp) 1227 tp->snd_cwnd = tp->t_segsz; 1228 } 1229 #endif 1230 1231 /* 1232 * On receipt of path MTU corrections, flush old route and replace it 1233 * with the new one. Retransmit all unacknowledged packets, to ensure 1234 * that all packets will be received. 1235 */ 1236 void 1237 tcp_mtudisc(inp, errno) 1238 struct inpcb *inp; 1239 int errno; 1240 { 1241 struct tcpcb *tp = intotcpcb(inp); 1242 struct rtentry *rt = in_pcbrtentry(inp); 1243 1244 if (tp != 0) { 1245 if (rt != 0) { 1246 /* 1247 * If this was not a host route, remove and realloc. 1248 */ 1249 if ((rt->rt_flags & RTF_HOST) == 0) { 1250 in_rtchange(inp, errno); 1251 if ((rt = in_pcbrtentry(inp)) == 0) 1252 return; 1253 } 1254 1255 /* 1256 * Slow start out of the error condition. We 1257 * use the MTU because we know it's smaller 1258 * than the previously transmitted segment. 1259 * 1260 * Note: This is more conservative than the 1261 * suggestion in draft-floyd-incr-init-win-03. 1262 */ 1263 if (rt->rt_rmx.rmx_mtu != 0) 1264 tp->snd_cwnd = 1265 TCP_INITIAL_WINDOW(tcp_init_win, 1266 rt->rt_rmx.rmx_mtu); 1267 } 1268 1269 /* 1270 * Resend unacknowledged packets. 1271 */ 1272 tp->snd_nxt = tp->snd_una; 1273 tcp_output(tp); 1274 } 1275 } 1276 1277 #if defined(INET6) && !defined(TCP6) 1278 void 1279 tcp6_mtudisc(in6p, errno) 1280 struct in6pcb *in6p; 1281 int errno; 1282 { 1283 struct tcpcb *tp = in6totcpcb(in6p); 1284 struct rtentry *rt = in6_pcbrtentry(in6p); 1285 1286 if (tp != 0) { 1287 if (rt != 0) { 1288 /* 1289 * If this was not a host route, remove and realloc. 1290 */ 1291 if ((rt->rt_flags & RTF_HOST) == 0) { 1292 in6_rtchange(in6p, errno); 1293 if ((rt = in6_pcbrtentry(in6p)) == 0) 1294 return; 1295 } 1296 1297 /* 1298 * Slow start out of the error condition. We 1299 * use the MTU because we know it's smaller 1300 * than the previously transmitted segment. 1301 * 1302 * Note: This is more conservative than the 1303 * suggestion in draft-floyd-incr-init-win-03. 1304 */ 1305 if (rt->rt_rmx.rmx_mtu != 0) 1306 tp->snd_cwnd = 1307 TCP_INITIAL_WINDOW(tcp_init_win, 1308 rt->rt_rmx.rmx_mtu); 1309 } 1310 1311 /* 1312 * Resend unacknowledged packets. 1313 */ 1314 tp->snd_nxt = tp->snd_una; 1315 tcp_output(tp); 1316 } 1317 } 1318 #endif 1319 1320 /* 1321 * Compute the MSS to advertise to the peer. Called only during 1322 * the 3-way handshake. If we are the server (peer initiated 1323 * connection), we are called with a pointer to the interface 1324 * on which the SYN packet arrived. If we are the client (we 1325 * initiated connection), we are called with a pointer to the 1326 * interface out which this connection should go. 1327 * 1328 * NOTE: Do not subtract IP option/extension header size nor IPsec 1329 * header size from MSS advertisement. MSS option must hold the maximum 1330 * segment size we can accept, so it must always be: 1331 * max(if mtu) - ip header - tcp header 1332 */ 1333 u_long 1334 tcp_mss_to_advertise(ifp, af) 1335 const struct ifnet *ifp; 1336 int af; 1337 { 1338 extern u_long in_maxmtu; 1339 u_long mss = 0; 1340 u_long hdrsiz; 1341 1342 /* 1343 * In order to avoid defeating path MTU discovery on the peer, 1344 * we advertise the max MTU of all attached networks as our MSS, 1345 * per RFC 1191, section 3.1. 1346 * 1347 * We provide the option to advertise just the MTU of 1348 * the interface on which we hope this connection will 1349 * be receiving. If we are responding to a SYN, we 1350 * will have a pretty good idea about this, but when 1351 * initiating a connection there is a bit more doubt. 1352 * 1353 * We also need to ensure that loopback has a large enough 1354 * MSS, as the loopback MTU is never included in in_maxmtu. 1355 */ 1356 1357 if (ifp != NULL) 1358 mss = ifp->if_mtu; 1359 1360 if (tcp_mss_ifmtu == 0) 1361 mss = max(in_maxmtu, mss); 1362 1363 switch (af) { 1364 case AF_INET: 1365 hdrsiz = sizeof(struct ip); 1366 break; 1367 #ifdef INET6 1368 case AF_INET6: 1369 hdrsiz = sizeof(struct ip6_hdr); 1370 break; 1371 #endif 1372 default: 1373 hdrsiz = 0; 1374 break; 1375 } 1376 hdrsiz += sizeof(struct tcphdr); 1377 if (mss > hdrsiz) 1378 mss -= hdrsiz; 1379 1380 mss = max(tcp_mssdflt, mss); 1381 return (mss); 1382 } 1383 1384 /* 1385 * Set connection variables based on the peer's advertised MSS. 1386 * We are passed the TCPCB for the actual connection. If we 1387 * are the server, we are called by the compressed state engine 1388 * when the 3-way handshake is complete. If we are the client, 1389 * we are called when we recieve the SYN,ACK from the server. 1390 * 1391 * NOTE: Our advertised MSS value must be initialized in the TCPCB 1392 * before this routine is called! 1393 */ 1394 void 1395 tcp_mss_from_peer(tp, offer) 1396 struct tcpcb *tp; 1397 int offer; 1398 { 1399 struct socket *so; 1400 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1401 struct rtentry *rt; 1402 #endif 1403 u_long bufsize; 1404 int mss; 1405 1406 so = NULL; 1407 rt = NULL; 1408 if (tp->t_inpcb) { 1409 so = tp->t_inpcb->inp_socket; 1410 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1411 rt = in_pcbrtentry(tp->t_inpcb); 1412 #endif 1413 } 1414 #ifdef INET6 1415 else if (tp->t_in6pcb) { 1416 so = tp->t_in6pcb->in6p_socket; 1417 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1418 #ifdef TCP6 1419 rt = NULL; 1420 #else 1421 rt = in6_pcbrtentry(tp->t_in6pcb); 1422 #endif 1423 #endif 1424 } 1425 #endif 1426 1427 /* 1428 * As per RFC1122, use the default MSS value, unless they 1429 * sent us an offer. Do not accept offers less than 32 bytes. 1430 */ 1431 mss = tcp_mssdflt; 1432 if (offer) 1433 mss = offer; 1434 mss = max(mss, 32); /* sanity */ 1435 tp->t_peermss = mss; 1436 mss -= tcp_optlen(tp); 1437 if (tp->t_inpcb) 1438 mss -= ip_optlen(tp->t_inpcb); 1439 #ifdef INET6 1440 else if (tp->t_in6pcb) 1441 mss -= ip6_optlen(tp->t_in6pcb); 1442 #endif 1443 1444 /* 1445 * If there's a pipesize, change the socket buffer to that size. 1446 * Make the socket buffer an integral number of MSS units. If 1447 * the MSS is larger than the socket buffer, artificially decrease 1448 * the MSS. 1449 */ 1450 #ifdef RTV_SPIPE 1451 if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0) 1452 bufsize = rt->rt_rmx.rmx_sendpipe; 1453 else 1454 #endif 1455 bufsize = so->so_snd.sb_hiwat; 1456 if (bufsize < mss) 1457 mss = bufsize; 1458 else { 1459 bufsize = roundup(bufsize, mss); 1460 if (bufsize > sb_max) 1461 bufsize = sb_max; 1462 (void) sbreserve(&so->so_snd, bufsize); 1463 } 1464 tp->t_segsz = mss; 1465 1466 #ifdef RTV_SSTHRESH 1467 if (rt != NULL && rt->rt_rmx.rmx_ssthresh) { 1468 /* 1469 * There's some sort of gateway or interface buffer 1470 * limit on the path. Use this to set the slow 1471 * start threshold, but set the threshold to no less 1472 * than 2 * MSS. 1473 */ 1474 tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh); 1475 } 1476 #endif 1477 } 1478 1479 /* 1480 * Processing necessary when a TCP connection is established. 1481 */ 1482 void 1483 tcp_established(tp) 1484 struct tcpcb *tp; 1485 { 1486 struct socket *so; 1487 #ifdef RTV_RPIPE 1488 struct rtentry *rt; 1489 #endif 1490 u_long bufsize; 1491 1492 so = NULL; 1493 rt = NULL; 1494 if (tp->t_inpcb) { 1495 so = tp->t_inpcb->inp_socket; 1496 #if defined(RTV_RPIPE) 1497 rt = in_pcbrtentry(tp->t_inpcb); 1498 #endif 1499 } 1500 #ifdef INET6 1501 else if (tp->t_in6pcb) { 1502 so = tp->t_in6pcb->in6p_socket; 1503 #if defined(RTV_RPIPE) 1504 #ifdef TCP6 1505 rt = NULL; 1506 #else 1507 rt = in6_pcbrtentry(tp->t_in6pcb); 1508 #endif 1509 #endif 1510 } 1511 #endif 1512 1513 tp->t_state = TCPS_ESTABLISHED; 1514 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle); 1515 1516 #ifdef RTV_RPIPE 1517 if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0) 1518 bufsize = rt->rt_rmx.rmx_recvpipe; 1519 else 1520 #endif 1521 bufsize = so->so_rcv.sb_hiwat; 1522 if (bufsize > tp->t_ourmss) { 1523 bufsize = roundup(bufsize, tp->t_ourmss); 1524 if (bufsize > sb_max) 1525 bufsize = sb_max; 1526 (void) sbreserve(&so->so_rcv, bufsize); 1527 } 1528 } 1529 1530 /* 1531 * Check if there's an initial rtt or rttvar. Convert from the 1532 * route-table units to scaled multiples of the slow timeout timer. 1533 * Called only during the 3-way handshake. 1534 */ 1535 void 1536 tcp_rmx_rtt(tp) 1537 struct tcpcb *tp; 1538 { 1539 #ifdef RTV_RTT 1540 struct rtentry *rt = NULL; 1541 int rtt; 1542 1543 if (tp->t_inpcb) 1544 rt = in_pcbrtentry(tp->t_inpcb); 1545 #ifdef INET6 1546 else if (tp->t_in6pcb) { 1547 #ifdef TCP6 1548 rt = NULL; 1549 #else 1550 rt = in6_pcbrtentry(tp->t_in6pcb); 1551 #endif 1552 } 1553 #endif 1554 if (rt == NULL) 1555 return; 1556 1557 if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) { 1558 /* 1559 * XXX The lock bit for MTU indicates that the value 1560 * is also a minimum value; this is subject to time. 1561 */ 1562 if (rt->rt_rmx.rmx_locks & RTV_RTT) 1563 TCPT_RANGESET(tp->t_rttmin, 1564 rtt / (RTM_RTTUNIT / PR_SLOWHZ), 1565 TCPTV_MIN, TCPTV_REXMTMAX); 1566 tp->t_srtt = rtt / 1567 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1568 if (rt->rt_rmx.rmx_rttvar) { 1569 tp->t_rttvar = rt->rt_rmx.rmx_rttvar / 1570 ((RTM_RTTUNIT / PR_SLOWHZ) >> 1571 (TCP_RTTVAR_SHIFT + 2)); 1572 } else { 1573 /* Default variation is +- 1 rtt */ 1574 tp->t_rttvar = 1575 tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT); 1576 } 1577 TCPT_RANGESET(tp->t_rxtcur, 1578 ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2), 1579 tp->t_rttmin, TCPTV_REXMTMAX); 1580 } 1581 #endif 1582 } 1583 1584 tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */ 1585 1586 /* 1587 * Get a new sequence value given a tcp control block 1588 */ 1589 tcp_seq 1590 tcp_new_iss(tp, len, addin) 1591 void *tp; 1592 u_long len; 1593 tcp_seq addin; 1594 { 1595 tcp_seq tcp_iss; 1596 1597 /* 1598 * Randomize. 1599 */ 1600 #if NRND > 0 1601 rnd_extract_data(&tcp_iss, sizeof(tcp_iss), RND_EXTRACT_ANY); 1602 #else 1603 tcp_iss = random(); 1604 #endif 1605 1606 /* 1607 * If we were asked to add some amount to a known value, 1608 * we will take a random value obtained above, mask off the upper 1609 * bits, and add in the known value. We also add in a constant to 1610 * ensure that we are at least a certain distance from the original 1611 * value. 1612 * 1613 * This is used when an old connection is in timed wait 1614 * and we have a new one coming in, for instance. 1615 */ 1616 if (addin != 0) { 1617 #ifdef TCPISS_DEBUG 1618 printf("Random %08x, ", tcp_iss); 1619 #endif 1620 tcp_iss &= TCP_ISS_RANDOM_MASK; 1621 tcp_iss += addin + TCP_ISSINCR; 1622 #ifdef TCPISS_DEBUG 1623 printf("Old ISS %08x, ISS %08x\n", addin, tcp_iss); 1624 #endif 1625 } else { 1626 tcp_iss &= TCP_ISS_RANDOM_MASK; 1627 tcp_iss += tcp_iss_seq; 1628 tcp_iss_seq += TCP_ISSINCR; 1629 #ifdef TCPISS_DEBUG 1630 printf("ISS %08x\n", tcp_iss); 1631 #endif 1632 } 1633 1634 if (tcp_compat_42) { 1635 /* 1636 * Limit it to the positive range for really old TCP 1637 * implementations. 1638 */ 1639 if (tcp_iss >= 0x80000000) 1640 tcp_iss &= 0x7fffffff; /* XXX */ 1641 } 1642 1643 return tcp_iss; 1644 } 1645 1646 #ifdef IPSEC 1647 /* compute ESP/AH header size for TCP, including outer IP header. */ 1648 size_t 1649 ipsec4_hdrsiz_tcp(tp) 1650 struct tcpcb *tp; 1651 { 1652 struct inpcb *inp; 1653 size_t hdrsiz; 1654 1655 /* XXX mapped addr case (tp->t_in6pcb) */ 1656 if (!tp || !tp->t_template || !(inp = tp->t_inpcb)) 1657 return 0; 1658 switch (tp->t_family) { 1659 case AF_INET: 1660 hdrsiz = ipsec4_hdrsiz(tp->t_template, inp); 1661 break; 1662 default: 1663 hdrsiz = 0; 1664 break; 1665 } 1666 1667 return hdrsiz; 1668 } 1669 1670 #if defined(INET6) && !defined(TCP6) 1671 size_t 1672 ipsec6_hdrsiz_tcp(tp) 1673 struct tcpcb *tp; 1674 { 1675 struct in6pcb *in6p; 1676 size_t hdrsiz; 1677 1678 if (!tp || !tp->t_template || !(in6p = tp->t_in6pcb)) 1679 return 0; 1680 switch (tp->t_family) { 1681 case AF_INET6: 1682 hdrsiz = ipsec6_hdrsiz(tp->t_template, in6p); 1683 break; 1684 case AF_INET: 1685 /* mapped address case - tricky */ 1686 default: 1687 hdrsiz = 0; 1688 break; 1689 } 1690 1691 return hdrsiz; 1692 } 1693 #endif 1694 #endif /*IPSEC*/ 1695 1696 /* 1697 * Determine the length of the TCP options for this connection. 1698 * 1699 * XXX: What do we do for SACK, when we add that? Just reserve 1700 * all of the space? Otherwise we can't exactly be incrementing 1701 * cwnd by an amount that varies depending on the amount we last 1702 * had to SACK! 1703 */ 1704 1705 u_int 1706 tcp_optlen(tp) 1707 struct tcpcb *tp; 1708 { 1709 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 1710 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1711 return TCPOLEN_TSTAMP_APPA; 1712 else 1713 return 0; 1714 } 1715