tcp_subr.c revision 1.101
1 /* $NetBSD: tcp_subr.c,v 1.101 2000/10/19 20:23:00 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, 2000 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 #include <netinet/icmp6.h> 144 #endif 145 146 #include <netinet/tcp.h> 147 #include <netinet/tcp_fsm.h> 148 #include <netinet/tcp_seq.h> 149 #include <netinet/tcp_timer.h> 150 #include <netinet/tcp_var.h> 151 #include <netinet/tcpip.h> 152 153 #ifdef IPSEC 154 #include <netinet6/ipsec.h> 155 #endif /*IPSEC*/ 156 157 #ifdef INET6 158 struct in6pcb tcb6; 159 #endif 160 161 /* patchable/settable parameters for tcp */ 162 int tcp_mssdflt = TCP_MSS; 163 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 164 int tcp_do_rfc1323 = 1; /* window scaling / timestamps (obsolete) */ 165 int tcp_do_sack = 1; /* selective acknowledgement */ 166 int tcp_do_win_scale = 1; /* RFC1323 window scaling */ 167 int tcp_do_timestamps = 1; /* RFC1323 timestamps */ 168 int tcp_do_newreno = 0; /* Use the New Reno algorithms */ 169 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ 170 int tcp_init_win = 1; 171 int tcp_mss_ifmtu = 0; 172 #ifdef TCP_COMPAT_42 173 int tcp_compat_42 = 1; 174 #else 175 int tcp_compat_42 = 0; 176 #endif 177 int tcp_rst_ppslim = 100; /* 100pps */ 178 179 /* tcb hash */ 180 #ifndef TCBHASHSIZE 181 #define TCBHASHSIZE 128 182 #endif 183 int tcbhashsize = TCBHASHSIZE; 184 185 /* syn hash parameters */ 186 #define TCP_SYN_HASH_SIZE 293 187 #define TCP_SYN_BUCKET_SIZE 35 188 int tcp_syn_cache_size = TCP_SYN_HASH_SIZE; 189 int tcp_syn_cache_limit = TCP_SYN_HASH_SIZE*TCP_SYN_BUCKET_SIZE; 190 int tcp_syn_bucket_limit = 3*TCP_SYN_BUCKET_SIZE; 191 struct syn_cache_head tcp_syn_cache[TCP_SYN_HASH_SIZE]; 192 int tcp_syn_cache_interval = 1; /* runs timer twice a second */ 193 194 int tcp_freeq __P((struct tcpcb *)); 195 196 #ifdef INET 197 void tcp_mtudisc_callback __P((struct in_addr)); 198 #endif 199 #ifdef INET6 200 void tcp6_mtudisc_callback __P((struct in6_addr *)); 201 #endif 202 203 void tcp_mtudisc __P((struct inpcb *, int)); 204 #ifdef INET6 205 void tcp6_mtudisc __P((struct in6pcb *, int)); 206 #endif 207 208 struct pool tcpcb_pool; 209 210 /* 211 * Tcp initialization 212 */ 213 void 214 tcp_init() 215 { 216 int hlen; 217 218 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl", 219 0, NULL, NULL, M_PCB); 220 in_pcbinit(&tcbtable, tcbhashsize, tcbhashsize); 221 #ifdef INET6 222 tcb6.in6p_next = tcb6.in6p_prev = &tcb6; 223 #endif 224 LIST_INIT(&tcp_delacks); 225 226 hlen = sizeof(struct ip) + sizeof(struct tcphdr); 227 #ifdef INET6 228 if (sizeof(struct ip) < sizeof(struct ip6_hdr)) 229 hlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 230 #endif 231 if (max_protohdr < hlen) 232 max_protohdr = hlen; 233 if (max_linkhdr + hlen > MHLEN) 234 panic("tcp_init"); 235 236 #ifdef INET 237 icmp_mtudisc_callback_register(tcp_mtudisc_callback); 238 #endif 239 #ifdef INET6 240 icmp6_mtudisc_callback_register(tcp6_mtudisc_callback); 241 #endif 242 243 /* Initialize the compressed state engine. */ 244 syn_cache_init(); 245 } 246 247 /* 248 * Create template to be used to send tcp packets on a connection. 249 * Call after host entry created, allocates an mbuf and fills 250 * in a skeletal tcp/ip header, minimizing the amount of work 251 * necessary when the connection is used. 252 */ 253 struct mbuf * 254 tcp_template(tp) 255 struct tcpcb *tp; 256 { 257 struct inpcb *inp = tp->t_inpcb; 258 #ifdef INET6 259 struct in6pcb *in6p = tp->t_in6pcb; 260 #endif 261 struct tcphdr *n; 262 struct mbuf *m; 263 int hlen; 264 265 switch (tp->t_family) { 266 case AF_INET: 267 hlen = sizeof(struct ip); 268 if (inp) 269 break; 270 #ifdef INET6 271 if (in6p) { 272 /* mapped addr case */ 273 if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_laddr) 274 && IN6_IS_ADDR_V4MAPPED(&in6p->in6p_faddr)) 275 break; 276 } 277 #endif 278 return NULL; /*EINVAL*/ 279 #ifdef INET6 280 case AF_INET6: 281 hlen = sizeof(struct ip6_hdr); 282 if (in6p) { 283 /* more sainty check? */ 284 break; 285 } 286 return NULL; /*EINVAL*/ 287 #endif 288 default: 289 hlen = 0; /*pacify gcc*/ 290 return NULL; /*EAFNOSUPPORT*/ 291 } 292 #ifdef DIAGNOSTIC 293 if (hlen + sizeof(struct tcphdr) > MCLBYTES) 294 panic("mclbytes too small for t_template"); 295 #endif 296 m = tp->t_template; 297 if (m && m->m_len == hlen + sizeof(struct tcphdr)) 298 ; 299 else { 300 if (m) 301 m_freem(m); 302 m = tp->t_template = NULL; 303 MGETHDR(m, M_DONTWAIT, MT_HEADER); 304 if (m && hlen + sizeof(struct tcphdr) > MHLEN) { 305 MCLGET(m, M_DONTWAIT); 306 if ((m->m_flags & M_EXT) == 0) { 307 m_free(m); 308 m = NULL; 309 } 310 } 311 if (m == NULL) 312 return NULL; 313 m->m_pkthdr.len = m->m_len = hlen + sizeof(struct tcphdr); 314 } 315 bzero(mtod(m, caddr_t), m->m_len); 316 switch (tp->t_family) { 317 case AF_INET: 318 { 319 struct ipovly *ipov; 320 mtod(m, struct ip *)->ip_v = 4; 321 ipov = mtod(m, struct ipovly *); 322 ipov->ih_pr = IPPROTO_TCP; 323 ipov->ih_len = htons(sizeof(struct tcphdr)); 324 if (inp) { 325 ipov->ih_src = inp->inp_laddr; 326 ipov->ih_dst = inp->inp_faddr; 327 } 328 #ifdef INET6 329 else if (in6p) { 330 /* mapped addr case */ 331 bcopy(&in6p->in6p_laddr.s6_addr32[3], &ipov->ih_src, 332 sizeof(ipov->ih_src)); 333 bcopy(&in6p->in6p_faddr.s6_addr32[3], &ipov->ih_dst, 334 sizeof(ipov->ih_dst)); 335 } 336 #endif 337 break; 338 } 339 #ifdef INET6 340 case AF_INET6: 341 { 342 struct ip6_hdr *ip6; 343 mtod(m, struct ip *)->ip_v = 6; 344 ip6 = mtod(m, struct ip6_hdr *); 345 ip6->ip6_nxt = IPPROTO_TCP; 346 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 347 ip6->ip6_src = in6p->in6p_laddr; 348 ip6->ip6_dst = in6p->in6p_faddr; 349 ip6->ip6_flow = in6p->in6p_flowinfo & IPV6_FLOWINFO_MASK; 350 if (ip6_auto_flowlabel) { 351 ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK; 352 ip6->ip6_flow |= 353 (htonl(ip6_flow_seq++) & IPV6_FLOWLABEL_MASK); 354 } 355 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 356 ip6->ip6_vfc |= IPV6_VERSION; 357 break; 358 } 359 #endif 360 } 361 n = (struct tcphdr *)(mtod(m, caddr_t) + hlen); 362 if (inp) { 363 n->th_sport = inp->inp_lport; 364 n->th_dport = inp->inp_fport; 365 } 366 #ifdef INET6 367 else if (in6p) { 368 n->th_sport = in6p->in6p_lport; 369 n->th_dport = in6p->in6p_fport; 370 } 371 #endif 372 n->th_seq = 0; 373 n->th_ack = 0; 374 n->th_x2 = 0; 375 n->th_off = 5; 376 n->th_flags = 0; 377 n->th_win = 0; 378 n->th_sum = 0; 379 n->th_urp = 0; 380 return (m); 381 } 382 383 /* 384 * Send a single message to the TCP at address specified by 385 * the given TCP/IP header. If m == 0, then we make a copy 386 * of the tcpiphdr at ti and send directly to the addressed host. 387 * This is used to force keep alive messages out using the TCP 388 * template for a connection tp->t_template. If flags are given 389 * then we send a message back to the TCP which originated the 390 * segment ti, and discard the mbuf containing it and any other 391 * attached mbufs. 392 * 393 * In any case the ack and sequence number of the transmitted 394 * segment are as specified by the parameters. 395 */ 396 int 397 tcp_respond(tp, template, m, th0, ack, seq, flags) 398 struct tcpcb *tp; 399 struct mbuf *template; 400 struct mbuf *m; 401 struct tcphdr *th0; 402 tcp_seq ack, seq; 403 int flags; 404 { 405 struct route *ro; 406 int error, tlen, win = 0; 407 int hlen; 408 struct ip *ip; 409 #ifdef INET6 410 struct ip6_hdr *ip6; 411 #endif 412 int family; /* family on packet, not inpcb/in6pcb! */ 413 struct tcphdr *th; 414 415 if (tp != NULL && (flags & TH_RST) == 0) { 416 #ifdef DIAGNOSTIC 417 if (tp->t_inpcb && tp->t_in6pcb) 418 panic("tcp_respond: both t_inpcb and t_in6pcb are set"); 419 #endif 420 #ifdef INET 421 if (tp->t_inpcb) 422 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 423 #endif 424 #ifdef INET6 425 if (tp->t_in6pcb) 426 win = sbspace(&tp->t_in6pcb->in6p_socket->so_rcv); 427 #endif 428 } 429 430 ip = NULL; 431 #ifdef INET6 432 ip6 = NULL; 433 #endif 434 if (m == 0) { 435 if (!template) 436 return EINVAL; 437 438 /* get family information from template */ 439 switch (mtod(template, struct ip *)->ip_v) { 440 case 4: 441 family = AF_INET; 442 hlen = sizeof(struct ip); 443 break; 444 #ifdef INET6 445 case 6: 446 family = AF_INET6; 447 hlen = sizeof(struct ip6_hdr); 448 break; 449 #endif 450 default: 451 return EAFNOSUPPORT; 452 } 453 454 MGETHDR(m, M_DONTWAIT, MT_HEADER); 455 if (m) { 456 MCLGET(m, M_DONTWAIT); 457 if ((m->m_flags & M_EXT) == 0) { 458 m_free(m); 459 m = NULL; 460 } 461 } 462 if (m == NULL) 463 return (ENOBUFS); 464 465 if (tcp_compat_42) 466 tlen = 1; 467 else 468 tlen = 0; 469 470 m->m_data += max_linkhdr; 471 bcopy(mtod(template, caddr_t), mtod(m, caddr_t), 472 template->m_len); 473 switch (family) { 474 case AF_INET: 475 ip = mtod(m, struct ip *); 476 th = (struct tcphdr *)(ip + 1); 477 break; 478 #ifdef INET6 479 case AF_INET6: 480 ip6 = mtod(m, struct ip6_hdr *); 481 th = (struct tcphdr *)(ip6 + 1); 482 break; 483 #endif 484 #if 0 485 default: 486 /* noone will visit here */ 487 m_freem(m); 488 return EAFNOSUPPORT; 489 #endif 490 } 491 flags = TH_ACK; 492 } else { 493 494 if ((m->m_flags & M_PKTHDR) == 0) { 495 #if 0 496 printf("non PKTHDR to tcp_respond\n"); 497 #endif 498 m_freem(m); 499 return EINVAL; 500 } 501 #ifdef DIAGNOSTIC 502 if (!th0) 503 panic("th0 == NULL in tcp_respond"); 504 #endif 505 506 /* get family information from m */ 507 switch (mtod(m, struct ip *)->ip_v) { 508 case 4: 509 family = AF_INET; 510 hlen = sizeof(struct ip); 511 ip = mtod(m, struct ip *); 512 break; 513 #ifdef INET6 514 case 6: 515 family = AF_INET6; 516 hlen = sizeof(struct ip6_hdr); 517 ip6 = mtod(m, struct ip6_hdr *); 518 break; 519 #endif 520 default: 521 m_freem(m); 522 return EAFNOSUPPORT; 523 } 524 if ((flags & TH_SYN) == 0 || sizeof(*th0) > (th0->th_off << 2)) 525 tlen = sizeof(*th0); 526 else 527 tlen = th0->th_off << 2; 528 529 if (m->m_len > hlen + tlen && (m->m_flags & M_EXT) == 0 && 530 mtod(m, caddr_t) + hlen == (caddr_t)th0) { 531 m->m_len = hlen + tlen; 532 m_freem(m->m_next); 533 m->m_next = NULL; 534 } else { 535 struct mbuf *n; 536 537 #ifdef DIAGNOSTIC 538 if (max_linkhdr + hlen + tlen > MCLBYTES) { 539 m_freem(m); 540 return EMSGSIZE; 541 } 542 #endif 543 MGETHDR(n, M_DONTWAIT, MT_HEADER); 544 if (n && max_linkhdr + hlen + tlen > MHLEN) { 545 MCLGET(n, M_DONTWAIT); 546 if ((n->m_flags & M_EXT) == 0) { 547 m_freem(n); 548 n = NULL; 549 } 550 } 551 if (!n) { 552 m_freem(m); 553 return ENOBUFS; 554 } 555 556 n->m_data += max_linkhdr; 557 n->m_len = hlen + tlen; 558 m_copyback(n, 0, hlen, mtod(m, caddr_t)); 559 m_copyback(n, hlen, tlen, (caddr_t)th0); 560 561 m_freem(m); 562 m = n; 563 n = NULL; 564 } 565 566 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 567 switch (family) { 568 case AF_INET: 569 ip = mtod(m, struct ip *); 570 th = (struct tcphdr *)(ip + 1); 571 ip->ip_p = IPPROTO_TCP; 572 xchg(ip->ip_dst, ip->ip_src, struct in_addr); 573 ip->ip_p = IPPROTO_TCP; 574 break; 575 #ifdef INET6 576 case AF_INET6: 577 ip6 = mtod(m, struct ip6_hdr *); 578 th = (struct tcphdr *)(ip6 + 1); 579 ip6->ip6_nxt = IPPROTO_TCP; 580 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 581 ip6->ip6_nxt = IPPROTO_TCP; 582 break; 583 #endif 584 #if 0 585 default: 586 /* noone will visit here */ 587 m_freem(m); 588 return EAFNOSUPPORT; 589 #endif 590 } 591 xchg(th->th_dport, th->th_sport, u_int16_t); 592 #undef xchg 593 tlen = 0; /*be friendly with the following code*/ 594 } 595 th->th_seq = htonl(seq); 596 th->th_ack = htonl(ack); 597 th->th_x2 = 0; 598 if ((flags & TH_SYN) == 0) { 599 if (tp) 600 win >>= tp->rcv_scale; 601 if (win > TCP_MAXWIN) 602 win = TCP_MAXWIN; 603 th->th_win = htons((u_int16_t)win); 604 th->th_off = sizeof (struct tcphdr) >> 2; 605 tlen += sizeof(*th); 606 } else 607 tlen += th->th_off << 2; 608 m->m_len = hlen + tlen; 609 m->m_pkthdr.len = hlen + tlen; 610 m->m_pkthdr.rcvif = (struct ifnet *) 0; 611 th->th_flags = flags; 612 th->th_urp = 0; 613 614 switch (family) { 615 #ifdef INET 616 case AF_INET: 617 { 618 struct ipovly *ipov = (struct ipovly *)ip; 619 bzero(ipov->ih_x1, sizeof ipov->ih_x1); 620 ipov->ih_len = htons((u_int16_t)tlen); 621 622 th->th_sum = 0; 623 th->th_sum = in_cksum(m, hlen + tlen); 624 ip->ip_len = hlen + tlen; /*will be flipped on output*/ 625 ip->ip_ttl = ip_defttl; 626 break; 627 } 628 #endif 629 #ifdef INET6 630 case AF_INET6: 631 { 632 th->th_sum = 0; 633 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), 634 tlen); 635 ip6->ip6_plen = ntohs(tlen); 636 if (tp && tp->t_in6pcb) { 637 struct ifnet *oifp; 638 ro = (struct route *)&tp->t_in6pcb->in6p_route; 639 oifp = ro->ro_rt ? ro->ro_rt->rt_ifp : NULL; 640 ip6->ip6_hlim = in6_selecthlim(tp->t_in6pcb, oifp); 641 } else 642 ip6->ip6_hlim = ip6_defhlim; 643 ip6->ip6_flow &= ~IPV6_FLOWINFO_MASK; 644 if (ip6_auto_flowlabel) { 645 ip6->ip6_flow |= 646 (htonl(ip6_flow_seq++) & IPV6_FLOWLABEL_MASK); 647 } 648 break; 649 } 650 #endif 651 } 652 653 #ifdef IPSEC 654 ipsec_setsocket(m, NULL); 655 #endif /*IPSEC*/ 656 657 if (tp != NULL && tp->t_inpcb != NULL) { 658 ro = &tp->t_inpcb->inp_route; 659 #ifdef IPSEC 660 ipsec_setsocket(m, tp->t_inpcb->inp_socket); 661 #endif 662 #ifdef DIAGNOSTIC 663 if (family != AF_INET) 664 panic("tcp_respond: address family mismatch"); 665 if (!in_hosteq(ip->ip_dst, tp->t_inpcb->inp_faddr)) { 666 panic("tcp_respond: ip_dst %x != inp_faddr %x", 667 ntohl(ip->ip_dst.s_addr), 668 ntohl(tp->t_inpcb->inp_faddr.s_addr)); 669 } 670 #endif 671 } 672 #ifdef INET6 673 else if (tp != NULL && tp->t_in6pcb != NULL) { 674 ro = (struct route *)&tp->t_in6pcb->in6p_route; 675 #ifdef IPSEC 676 ipsec_setsocket(m, tp->t_in6pcb->in6p_socket); 677 #endif 678 #ifdef DIAGNOSTIC 679 if (family == AF_INET) { 680 if (!IN6_IS_ADDR_V4MAPPED(&tp->t_in6pcb->in6p_faddr)) 681 panic("tcp_respond: not mapped addr"); 682 if (bcmp(&ip->ip_dst, 683 &tp->t_in6pcb->in6p_faddr.s6_addr32[3], 684 sizeof(ip->ip_dst)) != 0) { 685 panic("tcp_respond: ip_dst != in6p_faddr"); 686 } 687 } else if (family == AF_INET6) { 688 if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &tp->t_in6pcb->in6p_faddr)) 689 panic("tcp_respond: ip6_dst != in6p_faddr"); 690 } else 691 panic("tcp_respond: address family mismatch"); 692 #endif 693 } 694 #endif 695 else 696 ro = NULL; 697 698 switch (family) { 699 #ifdef INET 700 case AF_INET: 701 error = ip_output(m, NULL, ro, 702 (ip_mtudisc ? IP_MTUDISC : 0), 703 NULL); 704 break; 705 #endif 706 #ifdef INET6 707 case AF_INET6: 708 error = ip6_output(m, NULL, (struct route_in6 *)ro, 0, NULL, 709 NULL); 710 break; 711 #endif 712 default: 713 error = EAFNOSUPPORT; 714 break; 715 } 716 717 return (error); 718 } 719 720 /* 721 * Create a new TCP control block, making an 722 * empty reassembly queue and hooking it to the argument 723 * protocol control block. 724 */ 725 struct tcpcb * 726 tcp_newtcpcb(family, aux) 727 int family; /* selects inpcb, or in6pcb */ 728 void *aux; 729 { 730 struct tcpcb *tp; 731 732 switch (family) { 733 case PF_INET: 734 break; 735 #ifdef INET6 736 case PF_INET6: 737 break; 738 #endif 739 default: 740 return NULL; 741 } 742 743 tp = pool_get(&tcpcb_pool, PR_NOWAIT); 744 if (tp == NULL) 745 return (NULL); 746 bzero((caddr_t)tp, sizeof(struct tcpcb)); 747 LIST_INIT(&tp->segq); 748 LIST_INIT(&tp->timeq); 749 tp->t_family = family; /* may be overridden later on */ 750 tp->t_peermss = tcp_mssdflt; 751 tp->t_ourmss = tcp_mssdflt; 752 tp->t_segsz = tcp_mssdflt; 753 LIST_INIT(&tp->t_sc); 754 755 tp->t_flags = 0; 756 if (tcp_do_rfc1323 && tcp_do_win_scale) 757 tp->t_flags |= TF_REQ_SCALE; 758 if (tcp_do_rfc1323 && tcp_do_timestamps) 759 tp->t_flags |= TF_REQ_TSTMP; 760 if (tcp_do_sack == 2) 761 tp->t_flags |= TF_WILL_SACK; 762 else if (tcp_do_sack == 1) 763 tp->t_flags |= TF_WILL_SACK|TF_IGNR_RXSACK; 764 tp->t_flags |= TF_CANT_TXSACK; 765 switch (family) { 766 case PF_INET: 767 tp->t_inpcb = (struct inpcb *)aux; 768 break; 769 #ifdef INET6 770 case PF_INET6: 771 tp->t_in6pcb = (struct in6pcb *)aux; 772 break; 773 #endif 774 } 775 /* 776 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 777 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 778 * reasonable initial retransmit time. 779 */ 780 tp->t_srtt = TCPTV_SRTTBASE; 781 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1); 782 tp->t_rttmin = TCPTV_MIN; 783 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 784 TCPTV_MIN, TCPTV_REXMTMAX); 785 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 786 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 787 if (family == AF_INET) { 788 struct inpcb *inp = (struct inpcb *)aux; 789 inp->inp_ip.ip_ttl = ip_defttl; 790 inp->inp_ppcb = (caddr_t)tp; 791 } 792 #ifdef INET6 793 else if (family == AF_INET6) { 794 struct in6pcb *in6p = (struct in6pcb *)aux; 795 in6p->in6p_ip6.ip6_hlim = in6_selecthlim(in6p, 796 in6p->in6p_route.ro_rt ? in6p->in6p_route.ro_rt->rt_ifp 797 : NULL); 798 in6p->in6p_ppcb = (caddr_t)tp; 799 } 800 #endif 801 return (tp); 802 } 803 804 /* 805 * Drop a TCP connection, reporting 806 * the specified error. If connection is synchronized, 807 * then send a RST to peer. 808 */ 809 struct tcpcb * 810 tcp_drop(tp, errno) 811 struct tcpcb *tp; 812 int errno; 813 { 814 struct socket *so; 815 816 #ifdef DIAGNOSTIC 817 if (tp->t_inpcb && tp->t_in6pcb) 818 panic("tcp_drop: both t_inpcb and t_in6pcb are set"); 819 #endif 820 #ifdef INET 821 if (tp->t_inpcb) 822 so = tp->t_inpcb->inp_socket; 823 #endif 824 #ifdef INET6 825 if (tp->t_in6pcb) 826 so = tp->t_in6pcb->in6p_socket; 827 #endif 828 else 829 return NULL; 830 831 if (TCPS_HAVERCVDSYN(tp->t_state)) { 832 tp->t_state = TCPS_CLOSED; 833 (void) tcp_output(tp); 834 tcpstat.tcps_drops++; 835 } else 836 tcpstat.tcps_conndrops++; 837 if (errno == ETIMEDOUT && tp->t_softerror) 838 errno = tp->t_softerror; 839 so->so_error = errno; 840 return (tcp_close(tp)); 841 } 842 843 /* 844 * Close a TCP control block: 845 * discard all space held by the tcp 846 * discard internet protocol block 847 * wake up any sleepers 848 */ 849 struct tcpcb * 850 tcp_close(tp) 851 struct tcpcb *tp; 852 { 853 struct inpcb *inp; 854 #ifdef INET6 855 struct in6pcb *in6p; 856 #endif 857 struct socket *so; 858 #ifdef RTV_RTT 859 struct rtentry *rt; 860 #endif 861 struct route *ro; 862 863 inp = tp->t_inpcb; 864 #ifdef INET6 865 in6p = tp->t_in6pcb; 866 #endif 867 so = NULL; 868 ro = NULL; 869 if (inp) { 870 so = inp->inp_socket; 871 ro = &inp->inp_route; 872 } 873 #ifdef INET6 874 else if (in6p) { 875 so = in6p->in6p_socket; 876 ro = (struct route *)&in6p->in6p_route; 877 } 878 #endif 879 880 #ifdef RTV_RTT 881 /* 882 * If we sent enough data to get some meaningful characteristics, 883 * save them in the routing entry. 'Enough' is arbitrarily 884 * defined as the sendpipesize (default 4K) * 16. This would 885 * give us 16 rtt samples assuming we only get one sample per 886 * window (the usual case on a long haul net). 16 samples is 887 * enough for the srtt filter to converge to within 5% of the correct 888 * value; fewer samples and we could save a very bogus rtt. 889 * 890 * Don't update the default route's characteristics and don't 891 * update anything that the user "locked". 892 */ 893 if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) && 894 ro && (rt = ro->ro_rt) && 895 !in_nullhost(satosin(rt_key(rt))->sin_addr)) { 896 u_long i = 0; 897 898 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 899 i = tp->t_srtt * 900 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 901 if (rt->rt_rmx.rmx_rtt && i) 902 /* 903 * filter this update to half the old & half 904 * the new values, converting scale. 905 * See route.h and tcp_var.h for a 906 * description of the scaling constants. 907 */ 908 rt->rt_rmx.rmx_rtt = 909 (rt->rt_rmx.rmx_rtt + i) / 2; 910 else 911 rt->rt_rmx.rmx_rtt = i; 912 } 913 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 914 i = tp->t_rttvar * 915 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2)); 916 if (rt->rt_rmx.rmx_rttvar && i) 917 rt->rt_rmx.rmx_rttvar = 918 (rt->rt_rmx.rmx_rttvar + i) / 2; 919 else 920 rt->rt_rmx.rmx_rttvar = i; 921 } 922 /* 923 * update the pipelimit (ssthresh) if it has been updated 924 * already or if a pipesize was specified & the threshhold 925 * got below half the pipesize. I.e., wait for bad news 926 * before we start updating, then update on both good 927 * and bad news. 928 */ 929 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 930 (i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) || 931 i < (rt->rt_rmx.rmx_sendpipe / 2)) { 932 /* 933 * convert the limit from user data bytes to 934 * packets then to packet data bytes. 935 */ 936 i = (i + tp->t_segsz / 2) / tp->t_segsz; 937 if (i < 2) 938 i = 2; 939 i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr)); 940 if (rt->rt_rmx.rmx_ssthresh) 941 rt->rt_rmx.rmx_ssthresh = 942 (rt->rt_rmx.rmx_ssthresh + i) / 2; 943 else 944 rt->rt_rmx.rmx_ssthresh = i; 945 } 946 } 947 #endif /* RTV_RTT */ 948 /* free the reassembly queue, if any */ 949 TCP_REASS_LOCK(tp); 950 (void) tcp_freeq(tp); 951 TCP_REASS_UNLOCK(tp); 952 953 TCP_CLEAR_DELACK(tp); 954 syn_cache_cleanup(tp); 955 956 if (tp->t_template) { 957 m_free(tp->t_template); 958 tp->t_template = NULL; 959 } 960 pool_put(&tcpcb_pool, tp); 961 if (inp) { 962 inp->inp_ppcb = 0; 963 soisdisconnected(so); 964 in_pcbdetach(inp); 965 } 966 #ifdef INET6 967 else if (in6p) { 968 in6p->in6p_ppcb = 0; 969 soisdisconnected(so); 970 in6_pcbdetach(in6p); 971 } 972 #endif 973 tcpstat.tcps_closed++; 974 return ((struct tcpcb *)0); 975 } 976 977 int 978 tcp_freeq(tp) 979 struct tcpcb *tp; 980 { 981 struct ipqent *qe; 982 int rv = 0; 983 #ifdef TCPREASS_DEBUG 984 int i = 0; 985 #endif 986 987 TCP_REASS_LOCK_CHECK(tp); 988 989 while ((qe = tp->segq.lh_first) != NULL) { 990 #ifdef TCPREASS_DEBUG 991 printf("tcp_freeq[%p,%d]: %u:%u(%u) 0x%02x\n", 992 tp, i++, qe->ipqe_seq, qe->ipqe_seq + qe->ipqe_len, 993 qe->ipqe_len, qe->ipqe_flags & (TH_SYN|TH_FIN|TH_RST)); 994 #endif 995 LIST_REMOVE(qe, ipqe_q); 996 LIST_REMOVE(qe, ipqe_timeq); 997 m_freem(qe->ipqe_m); 998 pool_put(&ipqent_pool, qe); 999 rv = 1; 1000 } 1001 return (rv); 1002 } 1003 1004 /* 1005 * Protocol drain routine. Called when memory is in short supply. 1006 */ 1007 void 1008 tcp_drain() 1009 { 1010 struct inpcb *inp; 1011 struct tcpcb *tp; 1012 1013 /* 1014 * Free the sequence queue of all TCP connections. 1015 */ 1016 inp = tcbtable.inpt_queue.cqh_first; 1017 if (inp) /* XXX */ 1018 for (; inp != (struct inpcb *)&tcbtable.inpt_queue; 1019 inp = inp->inp_queue.cqe_next) { 1020 if ((tp = intotcpcb(inp)) != NULL) { 1021 /* 1022 * We may be called from a device's interrupt 1023 * context. If the tcpcb is already busy, 1024 * just bail out now. 1025 */ 1026 if (tcp_reass_lock_try(tp) == 0) 1027 continue; 1028 if (tcp_freeq(tp)) 1029 tcpstat.tcps_connsdrained++; 1030 TCP_REASS_UNLOCK(tp); 1031 } 1032 } 1033 } 1034 1035 /* 1036 * Notify a tcp user of an asynchronous error; 1037 * store error as soft error, but wake up user 1038 * (for now, won't do anything until can select for soft error). 1039 */ 1040 void 1041 tcp_notify(inp, error) 1042 struct inpcb *inp; 1043 int error; 1044 { 1045 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 1046 struct socket *so = inp->inp_socket; 1047 1048 /* 1049 * Ignore some errors if we are hooked up. 1050 * If connection hasn't completed, has retransmitted several times, 1051 * and receives a second error, give up now. This is better 1052 * than waiting a long time to establish a connection that 1053 * can never complete. 1054 */ 1055 if (tp->t_state == TCPS_ESTABLISHED && 1056 (error == EHOSTUNREACH || error == ENETUNREACH || 1057 error == EHOSTDOWN)) { 1058 return; 1059 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1060 tp->t_rxtshift > 3 && tp->t_softerror) 1061 so->so_error = error; 1062 else 1063 tp->t_softerror = error; 1064 wakeup((caddr_t) &so->so_timeo); 1065 sorwakeup(so); 1066 sowwakeup(so); 1067 } 1068 1069 #ifdef INET6 1070 void 1071 tcp6_notify(in6p, error) 1072 struct in6pcb *in6p; 1073 int error; 1074 { 1075 struct tcpcb *tp = (struct tcpcb *)in6p->in6p_ppcb; 1076 struct socket *so = in6p->in6p_socket; 1077 1078 /* 1079 * Ignore some errors if we are hooked up. 1080 * If connection hasn't completed, has retransmitted several times, 1081 * and receives a second error, give up now. This is better 1082 * than waiting a long time to establish a connection that 1083 * can never complete. 1084 */ 1085 if (tp->t_state == TCPS_ESTABLISHED && 1086 (error == EHOSTUNREACH || error == ENETUNREACH || 1087 error == EHOSTDOWN)) { 1088 return; 1089 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1090 tp->t_rxtshift > 3 && tp->t_softerror) 1091 so->so_error = error; 1092 else 1093 tp->t_softerror = error; 1094 wakeup((caddr_t) &so->so_timeo); 1095 sorwakeup(so); 1096 sowwakeup(so); 1097 } 1098 #endif 1099 1100 #ifdef INET6 1101 void 1102 tcp6_ctlinput(cmd, sa, d) 1103 int cmd; 1104 struct sockaddr *sa; 1105 void *d; 1106 { 1107 struct tcphdr *thp; 1108 struct tcphdr th; 1109 void (*notify) __P((struct in6pcb *, int)) = tcp6_notify; 1110 int nmatch; 1111 struct sockaddr_in6 sa6; 1112 struct ip6_hdr *ip6; 1113 struct mbuf *m; 1114 int off; 1115 struct in6_addr finaldst; 1116 struct in6_addr s; 1117 1118 if (sa->sa_family != AF_INET6 || 1119 sa->sa_len != sizeof(struct sockaddr_in6)) 1120 return; 1121 if ((unsigned)cmd >= PRC_NCMDS) 1122 return; 1123 else if (cmd == PRC_QUENCH) { 1124 /* XXX there's no PRC_QUENCH in IPv6 */ 1125 notify = tcp6_quench; 1126 } else if (PRC_IS_REDIRECT(cmd)) 1127 notify = in6_rtchange, d = NULL; 1128 else if (cmd == PRC_MSGSIZE) 1129 ; /* special code is present, see below */ 1130 else if (cmd == PRC_HOSTDEAD) 1131 d = NULL; 1132 else if (inet6ctlerrmap[cmd] == 0) 1133 return; 1134 1135 /* if the parameter is from icmp6, decode it. */ 1136 if (d != NULL) { 1137 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 1138 m = ip6cp->ip6c_m; 1139 ip6 = ip6cp->ip6c_ip6; 1140 off = ip6cp->ip6c_off; 1141 1142 /* translate addresses into internal form */ 1143 bcopy(ip6cp->ip6c_finaldst, &finaldst, sizeof(finaldst)); 1144 if (IN6_IS_ADDR_LINKLOCAL(&finaldst)) { 1145 finaldst.s6_addr16[1] = 1146 htons(m->m_pkthdr.rcvif->if_index); 1147 } 1148 bcopy(&ip6->ip6_src, &s, sizeof(s)); 1149 if (IN6_IS_ADDR_LINKLOCAL(&s)) 1150 s.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 1151 } else { 1152 m = NULL; 1153 ip6 = NULL; 1154 } 1155 1156 /* translate addresses into internal form */ 1157 sa6 = *(struct sockaddr_in6 *)sa; 1158 if (IN6_IS_ADDR_LINKLOCAL(&sa6.sin6_addr) && m && m->m_pkthdr.rcvif) 1159 sa6.sin6_addr.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 1160 1161 if (ip6) { 1162 /* 1163 * XXX: We assume that when ip6 is non NULL, 1164 * M and OFF are valid. 1165 */ 1166 1167 /* check if we can safely examine src and dst ports */ 1168 if (m->m_pkthdr.len < off + sizeof(th)) 1169 return; 1170 1171 if (m->m_len < off + sizeof(th)) { 1172 /* 1173 * this should be rare case, 1174 * so we compromise on this copy... 1175 */ 1176 m_copydata(m, off, sizeof(th), (caddr_t)&th); 1177 thp = &th; 1178 } else 1179 thp = (struct tcphdr *)(mtod(m, caddr_t) + off); 1180 1181 if (cmd == PRC_MSGSIZE) { 1182 /* 1183 * Check to see if we have a valid TCP connection 1184 * corresponding to the address in the ICMPv6 message 1185 * payload. 1186 */ 1187 if (!in6_pcblookup_connect(&tcb6, &finaldst, 1188 thp->th_dport, &s, thp->th_sport, 0)) 1189 return; 1190 1191 /* 1192 * Now that we've validated that we are actually 1193 * communicating with the host indicated in the ICMPv6 1194 * message, recalculate the new MTU, and create the 1195 * corresponding routing entry. 1196 */ 1197 icmp6_mtudisc_update((struct ip6ctlparam *)d); 1198 1199 return; 1200 } 1201 1202 nmatch = in6_pcbnotify(&tcb6, (struct sockaddr *)&sa6, 1203 thp->th_dport, &s, thp->th_sport, cmd, notify); 1204 if (nmatch == 0 && syn_cache_count && 1205 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 1206 inet6ctlerrmap[cmd] == ENETUNREACH || 1207 inet6ctlerrmap[cmd] == EHOSTDOWN)) { 1208 struct sockaddr_in6 sin6; 1209 bzero(&sin6, sizeof(sin6)); 1210 sin6.sin6_len = sizeof(sin6); 1211 sin6.sin6_family = AF_INET6; 1212 sin6.sin6_port = thp->th_sport; 1213 sin6.sin6_addr = s; 1214 syn_cache_unreach((struct sockaddr *)&sin6, sa, thp); 1215 } 1216 } else { 1217 (void) in6_pcbnotify(&tcb6, (struct sockaddr *)&sa6, 0, 1218 &zeroin6_addr, 0, cmd, notify); 1219 } 1220 } 1221 #endif 1222 1223 #ifdef INET 1224 /* assumes that ip header and tcp header are contiguous on mbuf */ 1225 void * 1226 tcp_ctlinput(cmd, sa, v) 1227 int cmd; 1228 struct sockaddr *sa; 1229 void *v; 1230 { 1231 struct ip *ip = v; 1232 struct tcphdr *th; 1233 struct icmp *icp; 1234 extern int inetctlerrmap[]; 1235 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1236 int errno; 1237 int nmatch; 1238 1239 if (sa->sa_family != AF_INET || 1240 sa->sa_len != sizeof(struct sockaddr_in)) 1241 return NULL; 1242 if ((unsigned)cmd >= PRC_NCMDS) 1243 return NULL; 1244 errno = inetctlerrmap[cmd]; 1245 if (cmd == PRC_QUENCH) 1246 notify = tcp_quench; 1247 else if (PRC_IS_REDIRECT(cmd)) 1248 notify = in_rtchange, ip = 0; 1249 else if (cmd == PRC_MSGSIZE && ip_mtudisc && ip && ip->ip_v == 4) { 1250 /* 1251 * Check to see if we have a valid TCP connection 1252 * corresponding to the address in the ICMP message 1253 * payload. 1254 */ 1255 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1256 if (in_pcblookup_connect(&tcbtable, 1257 ip->ip_dst, th->th_dport, 1258 ip->ip_src, th->th_sport) == NULL) 1259 return NULL; 1260 1261 /* 1262 * Now that we've validated that we are actually communicating 1263 * with the host indicated in the ICMP message, locate the 1264 * ICMP header, recalculate the new MTU, and create the 1265 * corresponding routing entry. 1266 */ 1267 icp = (struct icmp *)((caddr_t)ip - 1268 offsetof(struct icmp, icmp_ip)); 1269 icmp_mtudisc(icp, ip->ip_dst); 1270 1271 return NULL; 1272 } else if (cmd == PRC_HOSTDEAD) 1273 ip = 0; 1274 else if (errno == 0) 1275 return NULL; 1276 if (ip && ip->ip_v == 4 && sa->sa_family == AF_INET) { 1277 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1278 nmatch = in_pcbnotify(&tcbtable, satosin(sa)->sin_addr, 1279 th->th_dport, ip->ip_src, th->th_sport, errno, notify); 1280 if (nmatch == 0 && syn_cache_count && 1281 (inetctlerrmap[cmd] == EHOSTUNREACH || 1282 inetctlerrmap[cmd] == ENETUNREACH || 1283 inetctlerrmap[cmd] == EHOSTDOWN)) { 1284 struct sockaddr_in sin; 1285 bzero(&sin, sizeof(sin)); 1286 sin.sin_len = sizeof(sin); 1287 sin.sin_family = AF_INET; 1288 sin.sin_port = th->th_sport; 1289 sin.sin_addr = ip->ip_src; 1290 syn_cache_unreach((struct sockaddr *)&sin, sa, th); 1291 } 1292 1293 /* XXX mapped address case */ 1294 } else 1295 in_pcbnotifyall(&tcbtable, satosin(sa)->sin_addr, errno, 1296 notify); 1297 return NULL; 1298 } 1299 1300 /* 1301 * When a source quence is received, we are being notifed of congestion. 1302 * Close the congestion window down to the Loss Window (one segment). 1303 * We will gradually open it again as we proceed. 1304 */ 1305 void 1306 tcp_quench(inp, errno) 1307 struct inpcb *inp; 1308 int errno; 1309 { 1310 struct tcpcb *tp = intotcpcb(inp); 1311 1312 if (tp) 1313 tp->snd_cwnd = tp->t_segsz; 1314 } 1315 #endif 1316 1317 #ifdef INET6 1318 void 1319 tcp6_quench(in6p, errno) 1320 struct in6pcb *in6p; 1321 int errno; 1322 { 1323 struct tcpcb *tp = in6totcpcb(in6p); 1324 1325 if (tp) 1326 tp->snd_cwnd = tp->t_segsz; 1327 } 1328 #endif 1329 1330 #ifdef INET 1331 /* 1332 * Path MTU Discovery handlers. 1333 */ 1334 void 1335 tcp_mtudisc_callback(faddr) 1336 struct in_addr faddr; 1337 { 1338 1339 in_pcbnotifyall(&tcbtable, faddr, EMSGSIZE, tcp_mtudisc); 1340 } 1341 1342 /* 1343 * On receipt of path MTU corrections, flush old route and replace it 1344 * with the new one. Retransmit all unacknowledged packets, to ensure 1345 * that all packets will be received. 1346 */ 1347 void 1348 tcp_mtudisc(inp, errno) 1349 struct inpcb *inp; 1350 int errno; 1351 { 1352 struct tcpcb *tp = intotcpcb(inp); 1353 struct rtentry *rt = in_pcbrtentry(inp); 1354 1355 if (tp != 0) { 1356 if (rt != 0) { 1357 /* 1358 * If this was not a host route, remove and realloc. 1359 */ 1360 if ((rt->rt_flags & RTF_HOST) == 0) { 1361 in_rtchange(inp, errno); 1362 if ((rt = in_pcbrtentry(inp)) == 0) 1363 return; 1364 } 1365 1366 /* 1367 * Slow start out of the error condition. We 1368 * use the MTU because we know it's smaller 1369 * than the previously transmitted segment. 1370 * 1371 * Note: This is more conservative than the 1372 * suggestion in draft-floyd-incr-init-win-03. 1373 */ 1374 if (rt->rt_rmx.rmx_mtu != 0) 1375 tp->snd_cwnd = 1376 TCP_INITIAL_WINDOW(tcp_init_win, 1377 rt->rt_rmx.rmx_mtu); 1378 } 1379 1380 /* 1381 * Resend unacknowledged packets. 1382 */ 1383 tp->snd_nxt = tp->snd_una; 1384 tcp_output(tp); 1385 } 1386 } 1387 #endif 1388 1389 #ifdef INET6 1390 /* 1391 * Path MTU Discovery handlers. 1392 */ 1393 void 1394 tcp6_mtudisc_callback(faddr) 1395 struct in6_addr *faddr; 1396 { 1397 struct sockaddr_in6 sin6; 1398 1399 bzero(&sin6, sizeof(sin6)); 1400 sin6.sin6_family = AF_INET6; 1401 sin6.sin6_len = sizeof(struct sockaddr_in6); 1402 sin6.sin6_addr = *faddr; 1403 (void) in6_pcbnotify(&tcb6, (struct sockaddr *)&sin6, 0, 1404 &zeroin6_addr, 0, EMSGSIZE, tcp6_mtudisc); 1405 } 1406 1407 void 1408 tcp6_mtudisc(in6p, errno) 1409 struct in6pcb *in6p; 1410 int errno; 1411 { 1412 struct tcpcb *tp = in6totcpcb(in6p); 1413 struct rtentry *rt = in6_pcbrtentry(in6p); 1414 1415 if (tp != 0) { 1416 if (rt != 0) { 1417 /* 1418 * If this was not a host route, remove and realloc. 1419 */ 1420 if ((rt->rt_flags & RTF_HOST) == 0) { 1421 in6_rtchange(in6p, errno); 1422 if ((rt = in6_pcbrtentry(in6p)) == 0) 1423 return; 1424 } 1425 1426 /* 1427 * Slow start out of the error condition. We 1428 * use the MTU because we know it's smaller 1429 * than the previously transmitted segment. 1430 * 1431 * Note: This is more conservative than the 1432 * suggestion in draft-floyd-incr-init-win-03. 1433 */ 1434 if (rt->rt_rmx.rmx_mtu != 0) 1435 tp->snd_cwnd = 1436 TCP_INITIAL_WINDOW(tcp_init_win, 1437 rt->rt_rmx.rmx_mtu); 1438 } 1439 1440 /* 1441 * Resend unacknowledged packets. 1442 */ 1443 tp->snd_nxt = tp->snd_una; 1444 tcp_output(tp); 1445 } 1446 } 1447 #endif /* INET6 */ 1448 1449 /* 1450 * Compute the MSS to advertise to the peer. Called only during 1451 * the 3-way handshake. If we are the server (peer initiated 1452 * connection), we are called with a pointer to the interface 1453 * on which the SYN packet arrived. If we are the client (we 1454 * initiated connection), we are called with a pointer to the 1455 * interface out which this connection should go. 1456 * 1457 * NOTE: Do not subtract IP option/extension header size nor IPsec 1458 * header size from MSS advertisement. MSS option must hold the maximum 1459 * segment size we can accept, so it must always be: 1460 * max(if mtu) - ip header - tcp header 1461 */ 1462 u_long 1463 tcp_mss_to_advertise(ifp, af) 1464 const struct ifnet *ifp; 1465 int af; 1466 { 1467 extern u_long in_maxmtu; 1468 u_long mss = 0; 1469 u_long hdrsiz; 1470 1471 /* 1472 * In order to avoid defeating path MTU discovery on the peer, 1473 * we advertise the max MTU of all attached networks as our MSS, 1474 * per RFC 1191, section 3.1. 1475 * 1476 * We provide the option to advertise just the MTU of 1477 * the interface on which we hope this connection will 1478 * be receiving. If we are responding to a SYN, we 1479 * will have a pretty good idea about this, but when 1480 * initiating a connection there is a bit more doubt. 1481 * 1482 * We also need to ensure that loopback has a large enough 1483 * MSS, as the loopback MTU is never included in in_maxmtu. 1484 */ 1485 1486 if (ifp != NULL) 1487 mss = ifp->if_mtu; 1488 1489 if (tcp_mss_ifmtu == 0) 1490 mss = max(in_maxmtu, mss); 1491 1492 switch (af) { 1493 case AF_INET: 1494 hdrsiz = sizeof(struct ip); 1495 break; 1496 #ifdef INET6 1497 case AF_INET6: 1498 hdrsiz = sizeof(struct ip6_hdr); 1499 break; 1500 #endif 1501 default: 1502 hdrsiz = 0; 1503 break; 1504 } 1505 hdrsiz += sizeof(struct tcphdr); 1506 if (mss > hdrsiz) 1507 mss -= hdrsiz; 1508 1509 mss = max(tcp_mssdflt, mss); 1510 return (mss); 1511 } 1512 1513 /* 1514 * Set connection variables based on the peer's advertised MSS. 1515 * We are passed the TCPCB for the actual connection. If we 1516 * are the server, we are called by the compressed state engine 1517 * when the 3-way handshake is complete. If we are the client, 1518 * we are called when we recieve the SYN,ACK from the server. 1519 * 1520 * NOTE: Our advertised MSS value must be initialized in the TCPCB 1521 * before this routine is called! 1522 */ 1523 void 1524 tcp_mss_from_peer(tp, offer) 1525 struct tcpcb *tp; 1526 int offer; 1527 { 1528 struct socket *so; 1529 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1530 struct rtentry *rt; 1531 #endif 1532 u_long bufsize; 1533 int mss; 1534 1535 #ifdef DIAGNOSTIC 1536 if (tp->t_inpcb && tp->t_in6pcb) 1537 panic("tcp_mss_from_peer: both t_inpcb and t_in6pcb are set"); 1538 #endif 1539 so = NULL; 1540 rt = NULL; 1541 #ifdef INET 1542 if (tp->t_inpcb) { 1543 so = tp->t_inpcb->inp_socket; 1544 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1545 rt = in_pcbrtentry(tp->t_inpcb); 1546 #endif 1547 } 1548 #endif 1549 #ifdef INET6 1550 if (tp->t_in6pcb) { 1551 so = tp->t_in6pcb->in6p_socket; 1552 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1553 rt = in6_pcbrtentry(tp->t_in6pcb); 1554 #endif 1555 } 1556 #endif 1557 1558 /* 1559 * As per RFC1122, use the default MSS value, unless they 1560 * sent us an offer. Do not accept offers less than 32 bytes. 1561 */ 1562 mss = tcp_mssdflt; 1563 if (offer) 1564 mss = offer; 1565 mss = max(mss, 32); /* sanity */ 1566 tp->t_peermss = mss; 1567 mss -= tcp_optlen(tp); 1568 #ifdef INET 1569 if (tp->t_inpcb) 1570 mss -= ip_optlen(tp->t_inpcb); 1571 #endif 1572 #ifdef INET6 1573 if (tp->t_in6pcb) 1574 mss -= ip6_optlen(tp->t_in6pcb); 1575 #endif 1576 1577 /* 1578 * If there's a pipesize, change the socket buffer to that size. 1579 * Make the socket buffer an integral number of MSS units. If 1580 * the MSS is larger than the socket buffer, artificially decrease 1581 * the MSS. 1582 */ 1583 #ifdef RTV_SPIPE 1584 if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0) 1585 bufsize = rt->rt_rmx.rmx_sendpipe; 1586 else 1587 #endif 1588 bufsize = so->so_snd.sb_hiwat; 1589 if (bufsize < mss) 1590 mss = bufsize; 1591 else { 1592 bufsize = roundup(bufsize, mss); 1593 if (bufsize > sb_max) 1594 bufsize = sb_max; 1595 (void) sbreserve(&so->so_snd, bufsize); 1596 } 1597 tp->t_segsz = mss; 1598 1599 #ifdef RTV_SSTHRESH 1600 if (rt != NULL && rt->rt_rmx.rmx_ssthresh) { 1601 /* 1602 * There's some sort of gateway or interface buffer 1603 * limit on the path. Use this to set the slow 1604 * start threshold, but set the threshold to no less 1605 * than 2 * MSS. 1606 */ 1607 tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh); 1608 } 1609 #endif 1610 } 1611 1612 /* 1613 * Processing necessary when a TCP connection is established. 1614 */ 1615 void 1616 tcp_established(tp) 1617 struct tcpcb *tp; 1618 { 1619 struct socket *so; 1620 #ifdef RTV_RPIPE 1621 struct rtentry *rt; 1622 #endif 1623 u_long bufsize; 1624 1625 #ifdef DIAGNOSTIC 1626 if (tp->t_inpcb && tp->t_in6pcb) 1627 panic("tcp_established: both t_inpcb and t_in6pcb are set"); 1628 #endif 1629 so = NULL; 1630 rt = NULL; 1631 #ifdef INET 1632 if (tp->t_inpcb) { 1633 so = tp->t_inpcb->inp_socket; 1634 #if defined(RTV_RPIPE) 1635 rt = in_pcbrtentry(tp->t_inpcb); 1636 #endif 1637 } 1638 #endif 1639 #ifdef INET6 1640 if (tp->t_in6pcb) { 1641 so = tp->t_in6pcb->in6p_socket; 1642 #if defined(RTV_RPIPE) 1643 rt = in6_pcbrtentry(tp->t_in6pcb); 1644 #endif 1645 } 1646 #endif 1647 1648 tp->t_state = TCPS_ESTABLISHED; 1649 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle); 1650 1651 #ifdef RTV_RPIPE 1652 if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0) 1653 bufsize = rt->rt_rmx.rmx_recvpipe; 1654 else 1655 #endif 1656 bufsize = so->so_rcv.sb_hiwat; 1657 if (bufsize > tp->t_ourmss) { 1658 bufsize = roundup(bufsize, tp->t_ourmss); 1659 if (bufsize > sb_max) 1660 bufsize = sb_max; 1661 (void) sbreserve(&so->so_rcv, bufsize); 1662 } 1663 } 1664 1665 /* 1666 * Check if there's an initial rtt or rttvar. Convert from the 1667 * route-table units to scaled multiples of the slow timeout timer. 1668 * Called only during the 3-way handshake. 1669 */ 1670 void 1671 tcp_rmx_rtt(tp) 1672 struct tcpcb *tp; 1673 { 1674 #ifdef RTV_RTT 1675 struct rtentry *rt = NULL; 1676 int rtt; 1677 1678 #ifdef DIAGNOSTIC 1679 if (tp->t_inpcb && tp->t_in6pcb) 1680 panic("tcp_rmx_rtt: both t_inpcb and t_in6pcb are set"); 1681 #endif 1682 #ifdef INET 1683 if (tp->t_inpcb) 1684 rt = in_pcbrtentry(tp->t_inpcb); 1685 #endif 1686 #ifdef INET6 1687 if (tp->t_in6pcb) 1688 rt = in6_pcbrtentry(tp->t_in6pcb); 1689 #endif 1690 if (rt == NULL) 1691 return; 1692 1693 if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) { 1694 /* 1695 * XXX The lock bit for MTU indicates that the value 1696 * is also a minimum value; this is subject to time. 1697 */ 1698 if (rt->rt_rmx.rmx_locks & RTV_RTT) 1699 TCPT_RANGESET(tp->t_rttmin, 1700 rtt / (RTM_RTTUNIT / PR_SLOWHZ), 1701 TCPTV_MIN, TCPTV_REXMTMAX); 1702 tp->t_srtt = rtt / 1703 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1704 if (rt->rt_rmx.rmx_rttvar) { 1705 tp->t_rttvar = rt->rt_rmx.rmx_rttvar / 1706 ((RTM_RTTUNIT / PR_SLOWHZ) >> 1707 (TCP_RTTVAR_SHIFT + 2)); 1708 } else { 1709 /* Default variation is +- 1 rtt */ 1710 tp->t_rttvar = 1711 tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT); 1712 } 1713 TCPT_RANGESET(tp->t_rxtcur, 1714 ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2), 1715 tp->t_rttmin, TCPTV_REXMTMAX); 1716 } 1717 #endif 1718 } 1719 1720 tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */ 1721 1722 /* 1723 * Get a new sequence value given a tcp control block 1724 */ 1725 tcp_seq 1726 tcp_new_iss(tp, len, addin) 1727 void *tp; 1728 u_long len; 1729 tcp_seq addin; 1730 { 1731 tcp_seq tcp_iss; 1732 1733 /* 1734 * Randomize. 1735 */ 1736 #if NRND > 0 1737 rnd_extract_data(&tcp_iss, sizeof(tcp_iss), RND_EXTRACT_ANY); 1738 #else 1739 tcp_iss = random(); 1740 #endif 1741 1742 /* 1743 * If we were asked to add some amount to a known value, 1744 * we will take a random value obtained above, mask off the upper 1745 * bits, and add in the known value. We also add in a constant to 1746 * ensure that we are at least a certain distance from the original 1747 * value. 1748 * 1749 * This is used when an old connection is in timed wait 1750 * and we have a new one coming in, for instance. 1751 */ 1752 if (addin != 0) { 1753 #ifdef TCPISS_DEBUG 1754 printf("Random %08x, ", tcp_iss); 1755 #endif 1756 tcp_iss &= TCP_ISS_RANDOM_MASK; 1757 tcp_iss += addin + TCP_ISSINCR; 1758 #ifdef TCPISS_DEBUG 1759 printf("Old ISS %08x, ISS %08x\n", addin, tcp_iss); 1760 #endif 1761 } else { 1762 tcp_iss &= TCP_ISS_RANDOM_MASK; 1763 tcp_iss += tcp_iss_seq; 1764 tcp_iss_seq += TCP_ISSINCR; 1765 #ifdef TCPISS_DEBUG 1766 printf("ISS %08x\n", tcp_iss); 1767 #endif 1768 } 1769 1770 if (tcp_compat_42) { 1771 /* 1772 * Limit it to the positive range for really old TCP 1773 * implementations. 1774 */ 1775 if (tcp_iss >= 0x80000000) 1776 tcp_iss &= 0x7fffffff; /* XXX */ 1777 } 1778 1779 return tcp_iss; 1780 } 1781 1782 #ifdef IPSEC 1783 /* compute ESP/AH header size for TCP, including outer IP header. */ 1784 size_t 1785 ipsec4_hdrsiz_tcp(tp) 1786 struct tcpcb *tp; 1787 { 1788 struct inpcb *inp; 1789 size_t hdrsiz; 1790 1791 /* XXX mapped addr case (tp->t_in6pcb) */ 1792 if (!tp || !tp->t_template || !(inp = tp->t_inpcb)) 1793 return 0; 1794 switch (tp->t_family) { 1795 case AF_INET: 1796 /* XXX: should use currect direction. */ 1797 hdrsiz = ipsec4_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, inp); 1798 break; 1799 default: 1800 hdrsiz = 0; 1801 break; 1802 } 1803 1804 return hdrsiz; 1805 } 1806 1807 #ifdef INET6 1808 size_t 1809 ipsec6_hdrsiz_tcp(tp) 1810 struct tcpcb *tp; 1811 { 1812 struct in6pcb *in6p; 1813 size_t hdrsiz; 1814 1815 if (!tp || !tp->t_template || !(in6p = tp->t_in6pcb)) 1816 return 0; 1817 switch (tp->t_family) { 1818 case AF_INET6: 1819 /* XXX: should use currect direction. */ 1820 hdrsiz = ipsec6_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, in6p); 1821 break; 1822 case AF_INET: 1823 /* mapped address case - tricky */ 1824 default: 1825 hdrsiz = 0; 1826 break; 1827 } 1828 1829 return hdrsiz; 1830 } 1831 #endif 1832 #endif /*IPSEC*/ 1833 1834 /* 1835 * Determine the length of the TCP options for this connection. 1836 * 1837 * XXX: What do we do for SACK, when we add that? Just reserve 1838 * all of the space? Otherwise we can't exactly be incrementing 1839 * cwnd by an amount that varies depending on the amount we last 1840 * had to SACK! 1841 */ 1842 1843 u_int 1844 tcp_optlen(tp) 1845 struct tcpcb *tp; 1846 { 1847 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 1848 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1849 return TCPOLEN_TSTAMP_APPA; 1850 else 1851 return 0; 1852 } 1853
Indexes created Sun Sep 21 16:09:51 GMT 2025