tcp_subr.c revision 1.106
1 /* $NetBSD: tcp_subr.c,v 1.106 2001/01/24 09:04:16 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 (void)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 if (ipsec_setsocket(m, tp->t_inpcb->inp_socket) != 0) { 661 m_freem(m); 662 return ENOBUFS; 663 } 664 #endif 665 #ifdef DIAGNOSTIC 666 if (family != AF_INET) 667 panic("tcp_respond: address family mismatch"); 668 if (!in_hosteq(ip->ip_dst, tp->t_inpcb->inp_faddr)) { 669 panic("tcp_respond: ip_dst %x != inp_faddr %x", 670 ntohl(ip->ip_dst.s_addr), 671 ntohl(tp->t_inpcb->inp_faddr.s_addr)); 672 } 673 #endif 674 } 675 #ifdef INET6 676 else if (tp != NULL && tp->t_in6pcb != NULL) { 677 ro = (struct route *)&tp->t_in6pcb->in6p_route; 678 #ifdef IPSEC 679 if (ipsec_setsocket(m, tp->t_in6pcb->in6p_socket) != 0) { 680 m_freem(m); 681 return ENOBUFS; 682 } 683 #endif 684 #ifdef DIAGNOSTIC 685 if (family == AF_INET) { 686 if (!IN6_IS_ADDR_V4MAPPED(&tp->t_in6pcb->in6p_faddr)) 687 panic("tcp_respond: not mapped addr"); 688 if (bcmp(&ip->ip_dst, 689 &tp->t_in6pcb->in6p_faddr.s6_addr32[3], 690 sizeof(ip->ip_dst)) != 0) { 691 panic("tcp_respond: ip_dst != in6p_faddr"); 692 } 693 } else if (family == AF_INET6) { 694 if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &tp->t_in6pcb->in6p_faddr)) 695 panic("tcp_respond: ip6_dst != in6p_faddr"); 696 } else 697 panic("tcp_respond: address family mismatch"); 698 #endif 699 } 700 #endif 701 else 702 ro = NULL; 703 704 switch (family) { 705 #ifdef INET 706 case AF_INET: 707 error = ip_output(m, NULL, ro, 708 (ip_mtudisc ? IP_MTUDISC : 0), 709 NULL); 710 break; 711 #endif 712 #ifdef INET6 713 case AF_INET6: 714 error = ip6_output(m, NULL, (struct route_in6 *)ro, 0, NULL, 715 NULL); 716 break; 717 #endif 718 default: 719 error = EAFNOSUPPORT; 720 break; 721 } 722 723 return (error); 724 } 725 726 /* 727 * Create a new TCP control block, making an 728 * empty reassembly queue and hooking it to the argument 729 * protocol control block. 730 */ 731 struct tcpcb * 732 tcp_newtcpcb(family, aux) 733 int family; /* selects inpcb, or in6pcb */ 734 void *aux; 735 { 736 struct tcpcb *tp; 737 738 switch (family) { 739 case PF_INET: 740 break; 741 #ifdef INET6 742 case PF_INET6: 743 break; 744 #endif 745 default: 746 return NULL; 747 } 748 749 tp = pool_get(&tcpcb_pool, PR_NOWAIT); 750 if (tp == NULL) 751 return (NULL); 752 bzero((caddr_t)tp, sizeof(struct tcpcb)); 753 LIST_INIT(&tp->segq); 754 LIST_INIT(&tp->timeq); 755 tp->t_family = family; /* may be overridden later on */ 756 tp->t_peermss = tcp_mssdflt; 757 tp->t_ourmss = tcp_mssdflt; 758 tp->t_segsz = tcp_mssdflt; 759 LIST_INIT(&tp->t_sc); 760 761 tp->t_flags = 0; 762 if (tcp_do_rfc1323 && tcp_do_win_scale) 763 tp->t_flags |= TF_REQ_SCALE; 764 if (tcp_do_rfc1323 && tcp_do_timestamps) 765 tp->t_flags |= TF_REQ_TSTMP; 766 if (tcp_do_sack == 2) 767 tp->t_flags |= TF_WILL_SACK; 768 else if (tcp_do_sack == 1) 769 tp->t_flags |= TF_WILL_SACK|TF_IGNR_RXSACK; 770 tp->t_flags |= TF_CANT_TXSACK; 771 switch (family) { 772 case PF_INET: 773 tp->t_inpcb = (struct inpcb *)aux; 774 break; 775 #ifdef INET6 776 case PF_INET6: 777 tp->t_in6pcb = (struct in6pcb *)aux; 778 break; 779 #endif 780 } 781 /* 782 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 783 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 784 * reasonable initial retransmit time. 785 */ 786 tp->t_srtt = TCPTV_SRTTBASE; 787 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1); 788 tp->t_rttmin = TCPTV_MIN; 789 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 790 TCPTV_MIN, TCPTV_REXMTMAX); 791 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 792 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 793 if (family == AF_INET) { 794 struct inpcb *inp = (struct inpcb *)aux; 795 inp->inp_ip.ip_ttl = ip_defttl; 796 inp->inp_ppcb = (caddr_t)tp; 797 } 798 #ifdef INET6 799 else if (family == AF_INET6) { 800 struct in6pcb *in6p = (struct in6pcb *)aux; 801 in6p->in6p_ip6.ip6_hlim = in6_selecthlim(in6p, 802 in6p->in6p_route.ro_rt ? in6p->in6p_route.ro_rt->rt_ifp 803 : NULL); 804 in6p->in6p_ppcb = (caddr_t)tp; 805 } 806 #endif 807 return (tp); 808 } 809 810 /* 811 * Drop a TCP connection, reporting 812 * the specified error. If connection is synchronized, 813 * then send a RST to peer. 814 */ 815 struct tcpcb * 816 tcp_drop(tp, errno) 817 struct tcpcb *tp; 818 int errno; 819 { 820 struct socket *so = NULL; 821 822 #ifdef DIAGNOSTIC 823 if (tp->t_inpcb && tp->t_in6pcb) 824 panic("tcp_drop: both t_inpcb and t_in6pcb are set"); 825 #endif 826 #ifdef INET 827 if (tp->t_inpcb) 828 so = tp->t_inpcb->inp_socket; 829 #endif 830 #ifdef INET6 831 if (tp->t_in6pcb) 832 so = tp->t_in6pcb->in6p_socket; 833 #endif 834 if (!so) 835 return NULL; 836 837 if (TCPS_HAVERCVDSYN(tp->t_state)) { 838 tp->t_state = TCPS_CLOSED; 839 (void) tcp_output(tp); 840 tcpstat.tcps_drops++; 841 } else 842 tcpstat.tcps_conndrops++; 843 if (errno == ETIMEDOUT && tp->t_softerror) 844 errno = tp->t_softerror; 845 so->so_error = errno; 846 return (tcp_close(tp)); 847 } 848 849 /* 850 * Close a TCP control block: 851 * discard all space held by the tcp 852 * discard internet protocol block 853 * wake up any sleepers 854 */ 855 struct tcpcb * 856 tcp_close(tp) 857 struct tcpcb *tp; 858 { 859 struct inpcb *inp; 860 #ifdef INET6 861 struct in6pcb *in6p; 862 #endif 863 struct socket *so; 864 #ifdef RTV_RTT 865 struct rtentry *rt; 866 #endif 867 struct route *ro; 868 869 inp = tp->t_inpcb; 870 #ifdef INET6 871 in6p = tp->t_in6pcb; 872 #endif 873 so = NULL; 874 ro = NULL; 875 if (inp) { 876 so = inp->inp_socket; 877 ro = &inp->inp_route; 878 } 879 #ifdef INET6 880 else if (in6p) { 881 so = in6p->in6p_socket; 882 ro = (struct route *)&in6p->in6p_route; 883 } 884 #endif 885 886 #ifdef RTV_RTT 887 /* 888 * If we sent enough data to get some meaningful characteristics, 889 * save them in the routing entry. 'Enough' is arbitrarily 890 * defined as the sendpipesize (default 4K) * 16. This would 891 * give us 16 rtt samples assuming we only get one sample per 892 * window (the usual case on a long haul net). 16 samples is 893 * enough for the srtt filter to converge to within 5% of the correct 894 * value; fewer samples and we could save a very bogus rtt. 895 * 896 * Don't update the default route's characteristics and don't 897 * update anything that the user "locked". 898 */ 899 if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) && 900 ro && (rt = ro->ro_rt) && 901 !in_nullhost(satosin(rt_key(rt))->sin_addr)) { 902 u_long i = 0; 903 904 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 905 i = tp->t_srtt * 906 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 907 if (rt->rt_rmx.rmx_rtt && i) 908 /* 909 * filter this update to half the old & half 910 * the new values, converting scale. 911 * See route.h and tcp_var.h for a 912 * description of the scaling constants. 913 */ 914 rt->rt_rmx.rmx_rtt = 915 (rt->rt_rmx.rmx_rtt + i) / 2; 916 else 917 rt->rt_rmx.rmx_rtt = i; 918 } 919 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 920 i = tp->t_rttvar * 921 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2)); 922 if (rt->rt_rmx.rmx_rttvar && i) 923 rt->rt_rmx.rmx_rttvar = 924 (rt->rt_rmx.rmx_rttvar + i) / 2; 925 else 926 rt->rt_rmx.rmx_rttvar = i; 927 } 928 /* 929 * update the pipelimit (ssthresh) if it has been updated 930 * already or if a pipesize was specified & the threshhold 931 * got below half the pipesize. I.e., wait for bad news 932 * before we start updating, then update on both good 933 * and bad news. 934 */ 935 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 936 (i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) || 937 i < (rt->rt_rmx.rmx_sendpipe / 2)) { 938 /* 939 * convert the limit from user data bytes to 940 * packets then to packet data bytes. 941 */ 942 i = (i + tp->t_segsz / 2) / tp->t_segsz; 943 if (i < 2) 944 i = 2; 945 i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr)); 946 if (rt->rt_rmx.rmx_ssthresh) 947 rt->rt_rmx.rmx_ssthresh = 948 (rt->rt_rmx.rmx_ssthresh + i) / 2; 949 else 950 rt->rt_rmx.rmx_ssthresh = i; 951 } 952 } 953 #endif /* RTV_RTT */ 954 /* free the reassembly queue, if any */ 955 TCP_REASS_LOCK(tp); 956 (void) tcp_freeq(tp); 957 TCP_REASS_UNLOCK(tp); 958 959 TCP_CLEAR_DELACK(tp); 960 syn_cache_cleanup(tp); 961 962 if (tp->t_template) { 963 m_free(tp->t_template); 964 tp->t_template = NULL; 965 } 966 pool_put(&tcpcb_pool, tp); 967 if (inp) { 968 inp->inp_ppcb = 0; 969 soisdisconnected(so); 970 in_pcbdetach(inp); 971 } 972 #ifdef INET6 973 else if (in6p) { 974 in6p->in6p_ppcb = 0; 975 soisdisconnected(so); 976 in6_pcbdetach(in6p); 977 } 978 #endif 979 tcpstat.tcps_closed++; 980 return ((struct tcpcb *)0); 981 } 982 983 int 984 tcp_freeq(tp) 985 struct tcpcb *tp; 986 { 987 struct ipqent *qe; 988 int rv = 0; 989 #ifdef TCPREASS_DEBUG 990 int i = 0; 991 #endif 992 993 TCP_REASS_LOCK_CHECK(tp); 994 995 while ((qe = tp->segq.lh_first) != NULL) { 996 #ifdef TCPREASS_DEBUG 997 printf("tcp_freeq[%p,%d]: %u:%u(%u) 0x%02x\n", 998 tp, i++, qe->ipqe_seq, qe->ipqe_seq + qe->ipqe_len, 999 qe->ipqe_len, qe->ipqe_flags & (TH_SYN|TH_FIN|TH_RST)); 1000 #endif 1001 LIST_REMOVE(qe, ipqe_q); 1002 LIST_REMOVE(qe, ipqe_timeq); 1003 m_freem(qe->ipqe_m); 1004 pool_put(&ipqent_pool, qe); 1005 rv = 1; 1006 } 1007 return (rv); 1008 } 1009 1010 /* 1011 * Protocol drain routine. Called when memory is in short supply. 1012 */ 1013 void 1014 tcp_drain() 1015 { 1016 struct inpcb *inp; 1017 struct tcpcb *tp; 1018 1019 /* 1020 * Free the sequence queue of all TCP connections. 1021 */ 1022 inp = tcbtable.inpt_queue.cqh_first; 1023 if (inp) /* XXX */ 1024 for (; inp != (struct inpcb *)&tcbtable.inpt_queue; 1025 inp = inp->inp_queue.cqe_next) { 1026 if ((tp = intotcpcb(inp)) != NULL) { 1027 /* 1028 * We may be called from a device's interrupt 1029 * context. If the tcpcb is already busy, 1030 * just bail out now. 1031 */ 1032 if (tcp_reass_lock_try(tp) == 0) 1033 continue; 1034 if (tcp_freeq(tp)) 1035 tcpstat.tcps_connsdrained++; 1036 TCP_REASS_UNLOCK(tp); 1037 } 1038 } 1039 } 1040 1041 /* 1042 * Notify a tcp user of an asynchronous error; 1043 * store error as soft error, but wake up user 1044 * (for now, won't do anything until can select for soft error). 1045 */ 1046 void 1047 tcp_notify(inp, error) 1048 struct inpcb *inp; 1049 int error; 1050 { 1051 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 1052 struct socket *so = inp->inp_socket; 1053 1054 /* 1055 * Ignore some errors if we are hooked up. 1056 * If connection hasn't completed, has retransmitted several times, 1057 * and receives a second error, give up now. This is better 1058 * than waiting a long time to establish a connection that 1059 * can never complete. 1060 */ 1061 if (tp->t_state == TCPS_ESTABLISHED && 1062 (error == EHOSTUNREACH || error == ENETUNREACH || 1063 error == EHOSTDOWN)) { 1064 return; 1065 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1066 tp->t_rxtshift > 3 && tp->t_softerror) 1067 so->so_error = error; 1068 else 1069 tp->t_softerror = error; 1070 wakeup((caddr_t) &so->so_timeo); 1071 sorwakeup(so); 1072 sowwakeup(so); 1073 } 1074 1075 #ifdef INET6 1076 void 1077 tcp6_notify(in6p, error) 1078 struct in6pcb *in6p; 1079 int error; 1080 { 1081 struct tcpcb *tp = (struct tcpcb *)in6p->in6p_ppcb; 1082 struct socket *so = in6p->in6p_socket; 1083 1084 /* 1085 * Ignore some errors if we are hooked up. 1086 * If connection hasn't completed, has retransmitted several times, 1087 * and receives a second error, give up now. This is better 1088 * than waiting a long time to establish a connection that 1089 * can never complete. 1090 */ 1091 if (tp->t_state == TCPS_ESTABLISHED && 1092 (error == EHOSTUNREACH || error == ENETUNREACH || 1093 error == EHOSTDOWN)) { 1094 return; 1095 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1096 tp->t_rxtshift > 3 && tp->t_softerror) 1097 so->so_error = error; 1098 else 1099 tp->t_softerror = error; 1100 wakeup((caddr_t) &so->so_timeo); 1101 sorwakeup(so); 1102 sowwakeup(so); 1103 } 1104 #endif 1105 1106 #ifdef INET6 1107 void 1108 tcp6_ctlinput(cmd, sa, d) 1109 int cmd; 1110 struct sockaddr *sa; 1111 void *d; 1112 { 1113 struct tcphdr *thp; 1114 struct tcphdr th; 1115 void (*notify) __P((struct in6pcb *, int)) = tcp6_notify; 1116 int nmatch; 1117 struct sockaddr_in6 sa6; 1118 struct ip6_hdr *ip6; 1119 struct mbuf *m; 1120 int off; 1121 struct in6_addr finaldst; 1122 struct in6_addr s; 1123 1124 if (sa->sa_family != AF_INET6 || 1125 sa->sa_len != sizeof(struct sockaddr_in6)) 1126 return; 1127 if ((unsigned)cmd >= PRC_NCMDS) 1128 return; 1129 else if (cmd == PRC_QUENCH) { 1130 /* XXX there's no PRC_QUENCH in IPv6 */ 1131 notify = tcp6_quench; 1132 } else if (PRC_IS_REDIRECT(cmd)) 1133 notify = in6_rtchange, d = NULL; 1134 else if (cmd == PRC_MSGSIZE) 1135 ; /* special code is present, see below */ 1136 else if (cmd == PRC_HOSTDEAD) 1137 d = NULL; 1138 else if (inet6ctlerrmap[cmd] == 0) 1139 return; 1140 1141 /* if the parameter is from icmp6, decode it. */ 1142 if (d != NULL) { 1143 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 1144 m = ip6cp->ip6c_m; 1145 ip6 = ip6cp->ip6c_ip6; 1146 off = ip6cp->ip6c_off; 1147 1148 /* translate addresses into internal form */ 1149 bcopy(ip6cp->ip6c_finaldst, &finaldst, sizeof(finaldst)); 1150 if (IN6_IS_ADDR_LINKLOCAL(&finaldst)) { 1151 finaldst.s6_addr16[1] = 1152 htons(m->m_pkthdr.rcvif->if_index); 1153 } 1154 bcopy(&ip6->ip6_src, &s, sizeof(s)); 1155 if (IN6_IS_ADDR_LINKLOCAL(&s)) 1156 s.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 1157 } else { 1158 m = NULL; 1159 ip6 = NULL; 1160 } 1161 1162 /* translate addresses into internal form */ 1163 sa6 = *(struct sockaddr_in6 *)sa; 1164 if (IN6_IS_ADDR_LINKLOCAL(&sa6.sin6_addr) && m && m->m_pkthdr.rcvif) 1165 sa6.sin6_addr.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 1166 1167 if (ip6) { 1168 /* 1169 * XXX: We assume that when ip6 is non NULL, 1170 * M and OFF are valid. 1171 */ 1172 1173 /* check if we can safely examine src and dst ports */ 1174 if (m->m_pkthdr.len < off + sizeof(th)) 1175 return; 1176 1177 if (m->m_len < off + sizeof(th)) { 1178 /* 1179 * this should be rare case, 1180 * so we compromise on this copy... 1181 */ 1182 m_copydata(m, off, sizeof(th), (caddr_t)&th); 1183 thp = &th; 1184 } else 1185 thp = (struct tcphdr *)(mtod(m, caddr_t) + off); 1186 1187 if (cmd == PRC_MSGSIZE) { 1188 int valid = 0; 1189 1190 /* 1191 * Check to see if we have a valid TCP connection 1192 * corresponding to the address in the ICMPv6 message 1193 * payload. 1194 */ 1195 if (in6_pcblookup_connect(&tcb6, &finaldst, 1196 thp->th_dport, &s, thp->th_sport, 0)) 1197 valid++; 1198 1199 /* 1200 * Now that we've validated that we are actually 1201 * communicating with the host indicated in the ICMPv6 1202 * message, recalculate the new MTU, and create the 1203 * corresponding routing entry. 1204 */ 1205 icmp6_mtudisc_update((struct ip6ctlparam *)d, valid); 1206 1207 return; 1208 } 1209 1210 nmatch = in6_pcbnotify(&tcb6, (struct sockaddr *)&sa6, 1211 thp->th_dport, &s, thp->th_sport, cmd, notify); 1212 if (nmatch == 0 && syn_cache_count && 1213 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 1214 inet6ctlerrmap[cmd] == ENETUNREACH || 1215 inet6ctlerrmap[cmd] == EHOSTDOWN)) { 1216 struct sockaddr_in6 sin6; 1217 bzero(&sin6, sizeof(sin6)); 1218 sin6.sin6_len = sizeof(sin6); 1219 sin6.sin6_family = AF_INET6; 1220 sin6.sin6_port = thp->th_sport; 1221 sin6.sin6_addr = s; 1222 syn_cache_unreach((struct sockaddr *)&sin6, sa, thp); 1223 } 1224 } else { 1225 (void) in6_pcbnotify(&tcb6, (struct sockaddr *)&sa6, 0, 1226 &zeroin6_addr, 0, cmd, notify); 1227 } 1228 } 1229 #endif 1230 1231 #ifdef INET 1232 /* assumes that ip header and tcp header are contiguous on mbuf */ 1233 void * 1234 tcp_ctlinput(cmd, sa, v) 1235 int cmd; 1236 struct sockaddr *sa; 1237 void *v; 1238 { 1239 struct ip *ip = v; 1240 struct tcphdr *th; 1241 struct icmp *icp; 1242 extern int inetctlerrmap[]; 1243 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1244 int errno; 1245 int nmatch; 1246 1247 if (sa->sa_family != AF_INET || 1248 sa->sa_len != sizeof(struct sockaddr_in)) 1249 return NULL; 1250 if ((unsigned)cmd >= PRC_NCMDS) 1251 return NULL; 1252 errno = inetctlerrmap[cmd]; 1253 if (cmd == PRC_QUENCH) 1254 notify = tcp_quench; 1255 else if (PRC_IS_REDIRECT(cmd)) 1256 notify = in_rtchange, ip = 0; 1257 else if (cmd == PRC_MSGSIZE && ip_mtudisc && ip && ip->ip_v == 4) { 1258 /* 1259 * Check to see if we have a valid TCP connection 1260 * corresponding to the address in the ICMP message 1261 * payload. 1262 */ 1263 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1264 if (in_pcblookup_connect(&tcbtable, 1265 ip->ip_dst, th->th_dport, 1266 ip->ip_src, th->th_sport) == NULL) 1267 return NULL; 1268 1269 /* 1270 * Now that we've validated that we are actually communicating 1271 * with the host indicated in the ICMP message, locate the 1272 * ICMP header, recalculate the new MTU, and create the 1273 * corresponding routing entry. 1274 */ 1275 icp = (struct icmp *)((caddr_t)ip - 1276 offsetof(struct icmp, icmp_ip)); 1277 icmp_mtudisc(icp, ip->ip_dst); 1278 1279 return NULL; 1280 } else if (cmd == PRC_HOSTDEAD) 1281 ip = 0; 1282 else if (errno == 0) 1283 return NULL; 1284 if (ip && ip->ip_v == 4 && sa->sa_family == AF_INET) { 1285 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1286 nmatch = in_pcbnotify(&tcbtable, satosin(sa)->sin_addr, 1287 th->th_dport, ip->ip_src, th->th_sport, errno, notify); 1288 if (nmatch == 0 && syn_cache_count && 1289 (inetctlerrmap[cmd] == EHOSTUNREACH || 1290 inetctlerrmap[cmd] == ENETUNREACH || 1291 inetctlerrmap[cmd] == EHOSTDOWN)) { 1292 struct sockaddr_in sin; 1293 bzero(&sin, sizeof(sin)); 1294 sin.sin_len = sizeof(sin); 1295 sin.sin_family = AF_INET; 1296 sin.sin_port = th->th_sport; 1297 sin.sin_addr = ip->ip_src; 1298 syn_cache_unreach((struct sockaddr *)&sin, sa, th); 1299 } 1300 1301 /* XXX mapped address case */ 1302 } else 1303 in_pcbnotifyall(&tcbtable, satosin(sa)->sin_addr, errno, 1304 notify); 1305 return NULL; 1306 } 1307 1308 /* 1309 * When a source quence is received, we are being notifed of congestion. 1310 * Close the congestion window down to the Loss Window (one segment). 1311 * We will gradually open it again as we proceed. 1312 */ 1313 void 1314 tcp_quench(inp, errno) 1315 struct inpcb *inp; 1316 int errno; 1317 { 1318 struct tcpcb *tp = intotcpcb(inp); 1319 1320 if (tp) 1321 tp->snd_cwnd = tp->t_segsz; 1322 } 1323 #endif 1324 1325 #ifdef INET6 1326 void 1327 tcp6_quench(in6p, errno) 1328 struct in6pcb *in6p; 1329 int errno; 1330 { 1331 struct tcpcb *tp = in6totcpcb(in6p); 1332 1333 if (tp) 1334 tp->snd_cwnd = tp->t_segsz; 1335 } 1336 #endif 1337 1338 #ifdef INET 1339 /* 1340 * Path MTU Discovery handlers. 1341 */ 1342 void 1343 tcp_mtudisc_callback(faddr) 1344 struct in_addr faddr; 1345 { 1346 1347 in_pcbnotifyall(&tcbtable, faddr, EMSGSIZE, tcp_mtudisc); 1348 } 1349 1350 /* 1351 * On receipt of path MTU corrections, flush old route and replace it 1352 * with the new one. Retransmit all unacknowledged packets, to ensure 1353 * that all packets will be received. 1354 */ 1355 void 1356 tcp_mtudisc(inp, errno) 1357 struct inpcb *inp; 1358 int errno; 1359 { 1360 struct tcpcb *tp = intotcpcb(inp); 1361 struct rtentry *rt = in_pcbrtentry(inp); 1362 1363 if (tp != 0) { 1364 if (rt != 0) { 1365 /* 1366 * If this was not a host route, remove and realloc. 1367 */ 1368 if ((rt->rt_flags & RTF_HOST) == 0) { 1369 in_rtchange(inp, errno); 1370 if ((rt = in_pcbrtentry(inp)) == 0) 1371 return; 1372 } 1373 1374 /* 1375 * Slow start out of the error condition. We 1376 * use the MTU because we know it's smaller 1377 * than the previously transmitted segment. 1378 * 1379 * Note: This is more conservative than the 1380 * suggestion in draft-floyd-incr-init-win-03. 1381 */ 1382 if (rt->rt_rmx.rmx_mtu != 0) 1383 tp->snd_cwnd = 1384 TCP_INITIAL_WINDOW(tcp_init_win, 1385 rt->rt_rmx.rmx_mtu); 1386 } 1387 1388 /* 1389 * Resend unacknowledged packets. 1390 */ 1391 tp->snd_nxt = tp->snd_una; 1392 tcp_output(tp); 1393 } 1394 } 1395 #endif 1396 1397 #ifdef INET6 1398 /* 1399 * Path MTU Discovery handlers. 1400 */ 1401 void 1402 tcp6_mtudisc_callback(faddr) 1403 struct in6_addr *faddr; 1404 { 1405 struct sockaddr_in6 sin6; 1406 1407 bzero(&sin6, sizeof(sin6)); 1408 sin6.sin6_family = AF_INET6; 1409 sin6.sin6_len = sizeof(struct sockaddr_in6); 1410 sin6.sin6_addr = *faddr; 1411 (void) in6_pcbnotify(&tcb6, (struct sockaddr *)&sin6, 0, 1412 &zeroin6_addr, 0, PRC_MSGSIZE, tcp6_mtudisc); 1413 } 1414 1415 void 1416 tcp6_mtudisc(in6p, errno) 1417 struct in6pcb *in6p; 1418 int errno; 1419 { 1420 struct tcpcb *tp = in6totcpcb(in6p); 1421 struct rtentry *rt = in6_pcbrtentry(in6p); 1422 1423 if (tp != 0) { 1424 if (rt != 0) { 1425 /* 1426 * If this was not a host route, remove and realloc. 1427 */ 1428 if ((rt->rt_flags & RTF_HOST) == 0) { 1429 in6_rtchange(in6p, errno); 1430 if ((rt = in6_pcbrtentry(in6p)) == 0) 1431 return; 1432 } 1433 1434 /* 1435 * Slow start out of the error condition. We 1436 * use the MTU because we know it's smaller 1437 * than the previously transmitted segment. 1438 * 1439 * Note: This is more conservative than the 1440 * suggestion in draft-floyd-incr-init-win-03. 1441 */ 1442 if (rt->rt_rmx.rmx_mtu != 0) 1443 tp->snd_cwnd = 1444 TCP_INITIAL_WINDOW(tcp_init_win, 1445 rt->rt_rmx.rmx_mtu); 1446 } 1447 1448 /* 1449 * Resend unacknowledged packets. 1450 */ 1451 tp->snd_nxt = tp->snd_una; 1452 tcp_output(tp); 1453 } 1454 } 1455 #endif /* INET6 */ 1456 1457 /* 1458 * Compute the MSS to advertise to the peer. Called only during 1459 * the 3-way handshake. If we are the server (peer initiated 1460 * connection), we are called with a pointer to the interface 1461 * on which the SYN packet arrived. If we are the client (we 1462 * initiated connection), we are called with a pointer to the 1463 * interface out which this connection should go. 1464 * 1465 * NOTE: Do not subtract IP option/extension header size nor IPsec 1466 * header size from MSS advertisement. MSS option must hold the maximum 1467 * segment size we can accept, so it must always be: 1468 * max(if mtu) - ip header - tcp header 1469 */ 1470 u_long 1471 tcp_mss_to_advertise(ifp, af) 1472 const struct ifnet *ifp; 1473 int af; 1474 { 1475 extern u_long in_maxmtu; 1476 u_long mss = 0; 1477 u_long hdrsiz; 1478 1479 /* 1480 * In order to avoid defeating path MTU discovery on the peer, 1481 * we advertise the max MTU of all attached networks as our MSS, 1482 * per RFC 1191, section 3.1. 1483 * 1484 * We provide the option to advertise just the MTU of 1485 * the interface on which we hope this connection will 1486 * be receiving. If we are responding to a SYN, we 1487 * will have a pretty good idea about this, but when 1488 * initiating a connection there is a bit more doubt. 1489 * 1490 * We also need to ensure that loopback has a large enough 1491 * MSS, as the loopback MTU is never included in in_maxmtu. 1492 */ 1493 1494 if (ifp != NULL) 1495 mss = ifp->if_mtu; 1496 1497 if (tcp_mss_ifmtu == 0) 1498 mss = max(in_maxmtu, mss); 1499 1500 switch (af) { 1501 case AF_INET: 1502 hdrsiz = sizeof(struct ip); 1503 break; 1504 #ifdef INET6 1505 case AF_INET6: 1506 hdrsiz = sizeof(struct ip6_hdr); 1507 break; 1508 #endif 1509 default: 1510 hdrsiz = 0; 1511 break; 1512 } 1513 hdrsiz += sizeof(struct tcphdr); 1514 if (mss > hdrsiz) 1515 mss -= hdrsiz; 1516 1517 mss = max(tcp_mssdflt, mss); 1518 return (mss); 1519 } 1520 1521 /* 1522 * Set connection variables based on the peer's advertised MSS. 1523 * We are passed the TCPCB for the actual connection. If we 1524 * are the server, we are called by the compressed state engine 1525 * when the 3-way handshake is complete. If we are the client, 1526 * we are called when we recieve the SYN,ACK from the server. 1527 * 1528 * NOTE: Our advertised MSS value must be initialized in the TCPCB 1529 * before this routine is called! 1530 */ 1531 void 1532 tcp_mss_from_peer(tp, offer) 1533 struct tcpcb *tp; 1534 int offer; 1535 { 1536 struct socket *so; 1537 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1538 struct rtentry *rt; 1539 #endif 1540 u_long bufsize; 1541 int mss; 1542 1543 #ifdef DIAGNOSTIC 1544 if (tp->t_inpcb && tp->t_in6pcb) 1545 panic("tcp_mss_from_peer: both t_inpcb and t_in6pcb are set"); 1546 #endif 1547 so = NULL; 1548 rt = NULL; 1549 #ifdef INET 1550 if (tp->t_inpcb) { 1551 so = tp->t_inpcb->inp_socket; 1552 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1553 rt = in_pcbrtentry(tp->t_inpcb); 1554 #endif 1555 } 1556 #endif 1557 #ifdef INET6 1558 if (tp->t_in6pcb) { 1559 so = tp->t_in6pcb->in6p_socket; 1560 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1561 rt = in6_pcbrtentry(tp->t_in6pcb); 1562 #endif 1563 } 1564 #endif 1565 1566 /* 1567 * As per RFC1122, use the default MSS value, unless they 1568 * sent us an offer. Do not accept offers less than 32 bytes. 1569 */ 1570 mss = tcp_mssdflt; 1571 if (offer) 1572 mss = offer; 1573 mss = max(mss, 32); /* sanity */ 1574 tp->t_peermss = mss; 1575 mss -= tcp_optlen(tp); 1576 #ifdef INET 1577 if (tp->t_inpcb) 1578 mss -= ip_optlen(tp->t_inpcb); 1579 #endif 1580 #ifdef INET6 1581 if (tp->t_in6pcb) 1582 mss -= ip6_optlen(tp->t_in6pcb); 1583 #endif 1584 1585 /* 1586 * If there's a pipesize, change the socket buffer to that size. 1587 * Make the socket buffer an integral number of MSS units. If 1588 * the MSS is larger than the socket buffer, artificially decrease 1589 * the MSS. 1590 */ 1591 #ifdef RTV_SPIPE 1592 if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0) 1593 bufsize = rt->rt_rmx.rmx_sendpipe; 1594 else 1595 #endif 1596 bufsize = so->so_snd.sb_hiwat; 1597 if (bufsize < mss) 1598 mss = bufsize; 1599 else { 1600 bufsize = roundup(bufsize, mss); 1601 if (bufsize > sb_max) 1602 bufsize = sb_max; 1603 (void) sbreserve(&so->so_snd, bufsize); 1604 } 1605 tp->t_segsz = mss; 1606 1607 #ifdef RTV_SSTHRESH 1608 if (rt != NULL && rt->rt_rmx.rmx_ssthresh) { 1609 /* 1610 * There's some sort of gateway or interface buffer 1611 * limit on the path. Use this to set the slow 1612 * start threshold, but set the threshold to no less 1613 * than 2 * MSS. 1614 */ 1615 tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh); 1616 } 1617 #endif 1618 } 1619 1620 /* 1621 * Processing necessary when a TCP connection is established. 1622 */ 1623 void 1624 tcp_established(tp) 1625 struct tcpcb *tp; 1626 { 1627 struct socket *so; 1628 #ifdef RTV_RPIPE 1629 struct rtentry *rt; 1630 #endif 1631 u_long bufsize; 1632 1633 #ifdef DIAGNOSTIC 1634 if (tp->t_inpcb && tp->t_in6pcb) 1635 panic("tcp_established: both t_inpcb and t_in6pcb are set"); 1636 #endif 1637 so = NULL; 1638 rt = NULL; 1639 #ifdef INET 1640 if (tp->t_inpcb) { 1641 so = tp->t_inpcb->inp_socket; 1642 #if defined(RTV_RPIPE) 1643 rt = in_pcbrtentry(tp->t_inpcb); 1644 #endif 1645 } 1646 #endif 1647 #ifdef INET6 1648 if (tp->t_in6pcb) { 1649 so = tp->t_in6pcb->in6p_socket; 1650 #if defined(RTV_RPIPE) 1651 rt = in6_pcbrtentry(tp->t_in6pcb); 1652 #endif 1653 } 1654 #endif 1655 1656 tp->t_state = TCPS_ESTABLISHED; 1657 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle); 1658 1659 #ifdef RTV_RPIPE 1660 if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0) 1661 bufsize = rt->rt_rmx.rmx_recvpipe; 1662 else 1663 #endif 1664 bufsize = so->so_rcv.sb_hiwat; 1665 if (bufsize > tp->t_ourmss) { 1666 bufsize = roundup(bufsize, tp->t_ourmss); 1667 if (bufsize > sb_max) 1668 bufsize = sb_max; 1669 (void) sbreserve(&so->so_rcv, bufsize); 1670 } 1671 } 1672 1673 /* 1674 * Check if there's an initial rtt or rttvar. Convert from the 1675 * route-table units to scaled multiples of the slow timeout timer. 1676 * Called only during the 3-way handshake. 1677 */ 1678 void 1679 tcp_rmx_rtt(tp) 1680 struct tcpcb *tp; 1681 { 1682 #ifdef RTV_RTT 1683 struct rtentry *rt = NULL; 1684 int rtt; 1685 1686 #ifdef DIAGNOSTIC 1687 if (tp->t_inpcb && tp->t_in6pcb) 1688 panic("tcp_rmx_rtt: both t_inpcb and t_in6pcb are set"); 1689 #endif 1690 #ifdef INET 1691 if (tp->t_inpcb) 1692 rt = in_pcbrtentry(tp->t_inpcb); 1693 #endif 1694 #ifdef INET6 1695 if (tp->t_in6pcb) 1696 rt = in6_pcbrtentry(tp->t_in6pcb); 1697 #endif 1698 if (rt == NULL) 1699 return; 1700 1701 if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) { 1702 /* 1703 * XXX The lock bit for MTU indicates that the value 1704 * is also a minimum value; this is subject to time. 1705 */ 1706 if (rt->rt_rmx.rmx_locks & RTV_RTT) 1707 TCPT_RANGESET(tp->t_rttmin, 1708 rtt / (RTM_RTTUNIT / PR_SLOWHZ), 1709 TCPTV_MIN, TCPTV_REXMTMAX); 1710 tp->t_srtt = rtt / 1711 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1712 if (rt->rt_rmx.rmx_rttvar) { 1713 tp->t_rttvar = rt->rt_rmx.rmx_rttvar / 1714 ((RTM_RTTUNIT / PR_SLOWHZ) >> 1715 (TCP_RTTVAR_SHIFT + 2)); 1716 } else { 1717 /* Default variation is +- 1 rtt */ 1718 tp->t_rttvar = 1719 tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT); 1720 } 1721 TCPT_RANGESET(tp->t_rxtcur, 1722 ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2), 1723 tp->t_rttmin, TCPTV_REXMTMAX); 1724 } 1725 #endif 1726 } 1727 1728 tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */ 1729 1730 /* 1731 * Get a new sequence value given a tcp control block 1732 */ 1733 tcp_seq 1734 tcp_new_iss(tp, len, addin) 1735 void *tp; 1736 u_long len; 1737 tcp_seq addin; 1738 { 1739 tcp_seq tcp_iss; 1740 1741 /* 1742 * Randomize. 1743 */ 1744 #if NRND > 0 1745 rnd_extract_data(&tcp_iss, sizeof(tcp_iss), RND_EXTRACT_ANY); 1746 #else 1747 tcp_iss = random(); 1748 #endif 1749 1750 /* 1751 * If we were asked to add some amount to a known value, 1752 * we will take a random value obtained above, mask off the upper 1753 * bits, and add in the known value. We also add in a constant to 1754 * ensure that we are at least a certain distance from the original 1755 * value. 1756 * 1757 * This is used when an old connection is in timed wait 1758 * and we have a new one coming in, for instance. 1759 */ 1760 if (addin != 0) { 1761 #ifdef TCPISS_DEBUG 1762 printf("Random %08x, ", tcp_iss); 1763 #endif 1764 tcp_iss &= TCP_ISS_RANDOM_MASK; 1765 tcp_iss += addin + TCP_ISSINCR; 1766 #ifdef TCPISS_DEBUG 1767 printf("Old ISS %08x, ISS %08x\n", addin, tcp_iss); 1768 #endif 1769 } else { 1770 tcp_iss &= TCP_ISS_RANDOM_MASK; 1771 tcp_iss += tcp_iss_seq; 1772 tcp_iss_seq += TCP_ISSINCR; 1773 #ifdef TCPISS_DEBUG 1774 printf("ISS %08x\n", tcp_iss); 1775 #endif 1776 } 1777 1778 if (tcp_compat_42) { 1779 /* 1780 * Limit it to the positive range for really old TCP 1781 * implementations. 1782 */ 1783 if (tcp_iss >= 0x80000000) 1784 tcp_iss &= 0x7fffffff; /* XXX */ 1785 } 1786 1787 return tcp_iss; 1788 } 1789 1790 #ifdef IPSEC 1791 /* compute ESP/AH header size for TCP, including outer IP header. */ 1792 size_t 1793 ipsec4_hdrsiz_tcp(tp) 1794 struct tcpcb *tp; 1795 { 1796 struct inpcb *inp; 1797 size_t hdrsiz; 1798 1799 /* XXX mapped addr case (tp->t_in6pcb) */ 1800 if (!tp || !tp->t_template || !(inp = tp->t_inpcb)) 1801 return 0; 1802 switch (tp->t_family) { 1803 case AF_INET: 1804 /* XXX: should use currect direction. */ 1805 hdrsiz = ipsec4_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, inp); 1806 break; 1807 default: 1808 hdrsiz = 0; 1809 break; 1810 } 1811 1812 return hdrsiz; 1813 } 1814 1815 #ifdef INET6 1816 size_t 1817 ipsec6_hdrsiz_tcp(tp) 1818 struct tcpcb *tp; 1819 { 1820 struct in6pcb *in6p; 1821 size_t hdrsiz; 1822 1823 if (!tp || !tp->t_template || !(in6p = tp->t_in6pcb)) 1824 return 0; 1825 switch (tp->t_family) { 1826 case AF_INET6: 1827 /* XXX: should use currect direction. */ 1828 hdrsiz = ipsec6_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, in6p); 1829 break; 1830 case AF_INET: 1831 /* mapped address case - tricky */ 1832 default: 1833 hdrsiz = 0; 1834 break; 1835 } 1836 1837 return hdrsiz; 1838 } 1839 #endif 1840 #endif /*IPSEC*/ 1841 1842 /* 1843 * Determine the length of the TCP options for this connection. 1844 * 1845 * XXX: What do we do for SACK, when we add that? Just reserve 1846 * all of the space? Otherwise we can't exactly be incrementing 1847 * cwnd by an amount that varies depending on the amount we last 1848 * had to SACK! 1849 */ 1850 1851 u_int 1852 tcp_optlen(tp) 1853 struct tcpcb *tp; 1854 { 1855 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 1856 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1857 return TCPOLEN_TSTAMP_APPA; 1858 else 1859 return 0; 1860 } 1861
Indexes created Mon Sep 22 10:09:38 GMT 2025