tcp_subr.c revision 1.180
1 /* $NetBSD: tcp_subr.c,v 1.180 2005/02/12 01:24:07 heas 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, 2001 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. Neither the name of the University nor the names of its contributors 82 * may be used to endorse or promote products derived from this software 83 * without specific prior written permission. 84 * 85 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 86 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 87 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 88 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 89 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 90 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 91 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 92 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 93 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 94 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 95 * SUCH DAMAGE. 96 * 97 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 98 */ 99 100 #include <sys/cdefs.h> 101 __KERNEL_RCSID(0, "$NetBSD: tcp_subr.c,v 1.180 2005/02/12 01:24:07 heas Exp $"); 102 103 #include "opt_inet.h" 104 #include "opt_ipsec.h" 105 #include "opt_tcp_compat_42.h" 106 #include "opt_inet_csum.h" 107 #include "opt_mbuftrace.h" 108 #include "rnd.h" 109 110 #include <sys/param.h> 111 #include <sys/proc.h> 112 #include <sys/systm.h> 113 #include <sys/malloc.h> 114 #include <sys/mbuf.h> 115 #include <sys/socket.h> 116 #include <sys/socketvar.h> 117 #include <sys/protosw.h> 118 #include <sys/errno.h> 119 #include <sys/kernel.h> 120 #include <sys/pool.h> 121 #if NRND > 0 122 #include <sys/md5.h> 123 #include <sys/rnd.h> 124 #endif 125 126 #include <net/route.h> 127 #include <net/if.h> 128 129 #include <netinet/in.h> 130 #include <netinet/in_systm.h> 131 #include <netinet/ip.h> 132 #include <netinet/in_pcb.h> 133 #include <netinet/ip_var.h> 134 #include <netinet/ip_icmp.h> 135 136 #ifdef INET6 137 #ifndef INET 138 #include <netinet/in.h> 139 #endif 140 #include <netinet/ip6.h> 141 #include <netinet6/in6_pcb.h> 142 #include <netinet6/ip6_var.h> 143 #include <netinet6/in6_var.h> 144 #include <netinet6/ip6protosw.h> 145 #include <netinet/icmp6.h> 146 #include <netinet6/nd6.h> 147 #endif 148 149 #include <netinet/tcp.h> 150 #include <netinet/tcp_fsm.h> 151 #include <netinet/tcp_seq.h> 152 #include <netinet/tcp_timer.h> 153 #include <netinet/tcp_var.h> 154 #include <netinet/tcpip.h> 155 156 #ifdef IPSEC 157 #include <netinet6/ipsec.h> 158 #include <netkey/key.h> 159 #endif /*IPSEC*/ 160 161 #ifdef FAST_IPSEC 162 #include <netipsec/ipsec.h> 163 #include <netipsec/xform.h> 164 #ifdef INET6 165 #include <netipsec/ipsec6.h> 166 #endif 167 #include <netipsec/key.h> 168 #endif /* FAST_IPSEC*/ 169 170 171 struct inpcbtable tcbtable; /* head of queue of active tcpcb's */ 172 struct tcpstat tcpstat; /* tcp statistics */ 173 u_int32_t tcp_now; /* for RFC 1323 timestamps */ 174 175 /* patchable/settable parameters for tcp */ 176 int tcp_mssdflt = TCP_MSS; 177 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 178 int tcp_do_rfc1323 = 1; /* window scaling / timestamps (obsolete) */ 179 #if NRND > 0 180 int tcp_do_rfc1948 = 0; /* ISS by cryptographic hash */ 181 #endif 182 int tcp_do_sack = 1; /* selective acknowledgement */ 183 int tcp_do_win_scale = 1; /* RFC1323 window scaling */ 184 int tcp_do_timestamps = 1; /* RFC1323 timestamps */ 185 int tcp_do_newreno = 1; /* Use the New Reno algorithms */ 186 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ 187 #ifndef TCP_INIT_WIN 188 #define TCP_INIT_WIN 0 /* initial slow start window */ 189 #endif 190 #ifndef TCP_INIT_WIN_LOCAL 191 #define TCP_INIT_WIN_LOCAL 4 /* initial slow start window for local nets */ 192 #endif 193 int tcp_init_win = TCP_INIT_WIN; 194 int tcp_init_win_local = TCP_INIT_WIN_LOCAL; 195 int tcp_mss_ifmtu = 0; 196 #ifdef TCP_COMPAT_42 197 int tcp_compat_42 = 1; 198 #else 199 int tcp_compat_42 = 0; 200 #endif 201 int tcp_rst_ppslim = 100; /* 100pps */ 202 int tcp_ackdrop_ppslim = 100; /* 100pps */ 203 int tcp_do_loopback_cksum = 0; 204 205 /* tcb hash */ 206 #ifndef TCBHASHSIZE 207 #define TCBHASHSIZE 128 208 #endif 209 int tcbhashsize = TCBHASHSIZE; 210 211 /* syn hash parameters */ 212 #define TCP_SYN_HASH_SIZE 293 213 #define TCP_SYN_BUCKET_SIZE 35 214 int tcp_syn_cache_size = TCP_SYN_HASH_SIZE; 215 int tcp_syn_cache_limit = TCP_SYN_HASH_SIZE*TCP_SYN_BUCKET_SIZE; 216 int tcp_syn_bucket_limit = 3*TCP_SYN_BUCKET_SIZE; 217 struct syn_cache_head tcp_syn_cache[TCP_SYN_HASH_SIZE]; 218 219 int tcp_freeq(struct tcpcb *); 220 221 #ifdef INET 222 void tcp_mtudisc_callback(struct in_addr); 223 #endif 224 #ifdef INET6 225 void tcp6_mtudisc_callback(struct in6_addr *); 226 #endif 227 228 void tcp_mtudisc(struct inpcb *, int); 229 #ifdef INET6 230 void tcp6_mtudisc(struct in6pcb *, int); 231 #endif 232 233 POOL_INIT(tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl", NULL); 234 235 #ifdef TCP_CSUM_COUNTERS 236 #include <sys/device.h> 237 238 struct evcnt tcp_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 239 NULL, "tcp", "hwcsum bad"); 240 struct evcnt tcp_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 241 NULL, "tcp", "hwcsum ok"); 242 struct evcnt tcp_hwcsum_data = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 243 NULL, "tcp", "hwcsum data"); 244 struct evcnt tcp_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 245 NULL, "tcp", "swcsum"); 246 247 EVCNT_ATTACH_STATIC(tcp_hwcsum_bad); 248 EVCNT_ATTACH_STATIC(tcp_hwcsum_ok); 249 EVCNT_ATTACH_STATIC(tcp_hwcsum_data); 250 EVCNT_ATTACH_STATIC(tcp_swcsum); 251 #endif /* TCP_CSUM_COUNTERS */ 252 253 254 #ifdef TCP_OUTPUT_COUNTERS 255 #include <sys/device.h> 256 257 struct evcnt tcp_output_bigheader = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 258 NULL, "tcp", "output big header"); 259 struct evcnt tcp_output_predict_hit = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 260 NULL, "tcp", "output predict hit"); 261 struct evcnt tcp_output_predict_miss = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 262 NULL, "tcp", "output predict miss"); 263 struct evcnt tcp_output_copysmall = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 264 NULL, "tcp", "output copy small"); 265 struct evcnt tcp_output_copybig = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 266 NULL, "tcp", "output copy big"); 267 struct evcnt tcp_output_refbig = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 268 NULL, "tcp", "output reference big"); 269 270 EVCNT_ATTACH_STATIC(tcp_output_bigheader); 271 EVCNT_ATTACH_STATIC(tcp_output_predict_hit); 272 EVCNT_ATTACH_STATIC(tcp_output_predict_miss); 273 EVCNT_ATTACH_STATIC(tcp_output_copysmall); 274 EVCNT_ATTACH_STATIC(tcp_output_copybig); 275 EVCNT_ATTACH_STATIC(tcp_output_refbig); 276 277 #endif /* TCP_OUTPUT_COUNTERS */ 278 279 #ifdef TCP_REASS_COUNTERS 280 #include <sys/device.h> 281 282 struct evcnt tcp_reass_ = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 283 NULL, "tcp_reass", "calls"); 284 struct evcnt tcp_reass_empty = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 285 &tcp_reass_, "tcp_reass", "insert into empty queue"); 286 struct evcnt tcp_reass_iteration[8] = { 287 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", ">7 iterations"), 288 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "1 iteration"), 289 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "2 iterations"), 290 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "3 iterations"), 291 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "4 iterations"), 292 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "5 iterations"), 293 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "6 iterations"), 294 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "7 iterations"), 295 }; 296 struct evcnt tcp_reass_prependfirst = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 297 &tcp_reass_, "tcp_reass", "prepend to first"); 298 struct evcnt tcp_reass_prepend = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 299 &tcp_reass_, "tcp_reass", "prepend"); 300 struct evcnt tcp_reass_insert = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 301 &tcp_reass_, "tcp_reass", "insert"); 302 struct evcnt tcp_reass_inserttail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 303 &tcp_reass_, "tcp_reass", "insert at tail"); 304 struct evcnt tcp_reass_append = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 305 &tcp_reass_, "tcp_reass", "append"); 306 struct evcnt tcp_reass_appendtail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 307 &tcp_reass_, "tcp_reass", "append to tail fragment"); 308 struct evcnt tcp_reass_overlaptail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 309 &tcp_reass_, "tcp_reass", "overlap at end"); 310 struct evcnt tcp_reass_overlapfront = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 311 &tcp_reass_, "tcp_reass", "overlap at start"); 312 struct evcnt tcp_reass_segdup = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 313 &tcp_reass_, "tcp_reass", "duplicate segment"); 314 struct evcnt tcp_reass_fragdup = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 315 &tcp_reass_, "tcp_reass", "duplicate fragment"); 316 317 EVCNT_ATTACH_STATIC(tcp_reass_); 318 EVCNT_ATTACH_STATIC(tcp_reass_empty); 319 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 0); 320 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 1); 321 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 2); 322 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 3); 323 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 4); 324 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 5); 325 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 6); 326 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 7); 327 EVCNT_ATTACH_STATIC(tcp_reass_prependfirst); 328 EVCNT_ATTACH_STATIC(tcp_reass_prepend); 329 EVCNT_ATTACH_STATIC(tcp_reass_insert); 330 EVCNT_ATTACH_STATIC(tcp_reass_inserttail); 331 EVCNT_ATTACH_STATIC(tcp_reass_append); 332 EVCNT_ATTACH_STATIC(tcp_reass_appendtail); 333 EVCNT_ATTACH_STATIC(tcp_reass_overlaptail); 334 EVCNT_ATTACH_STATIC(tcp_reass_overlapfront); 335 EVCNT_ATTACH_STATIC(tcp_reass_segdup); 336 EVCNT_ATTACH_STATIC(tcp_reass_fragdup); 337 338 #endif /* TCP_REASS_COUNTERS */ 339 340 #ifdef MBUFTRACE 341 struct mowner tcp_mowner = { "tcp" }; 342 struct mowner tcp_rx_mowner = { "tcp", "rx" }; 343 struct mowner tcp_tx_mowner = { "tcp", "tx" }; 344 #endif 345 346 /* 347 * Tcp initialization 348 */ 349 void 350 tcp_init(void) 351 { 352 int hlen; 353 354 /* Initialize the TCPCB template. */ 355 tcp_tcpcb_template(); 356 357 in_pcbinit(&tcbtable, tcbhashsize, tcbhashsize); 358 359 hlen = sizeof(struct ip) + sizeof(struct tcphdr); 360 #ifdef INET6 361 if (sizeof(struct ip) < sizeof(struct ip6_hdr)) 362 hlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 363 #endif 364 if (max_protohdr < hlen) 365 max_protohdr = hlen; 366 if (max_linkhdr + hlen > MHLEN) 367 panic("tcp_init"); 368 369 #ifdef INET 370 icmp_mtudisc_callback_register(tcp_mtudisc_callback); 371 #endif 372 #ifdef INET6 373 icmp6_mtudisc_callback_register(tcp6_mtudisc_callback); 374 #endif 375 376 /* Initialize timer state. */ 377 tcp_timer_init(); 378 379 /* Initialize the compressed state engine. */ 380 syn_cache_init(); 381 382 MOWNER_ATTACH(&tcp_tx_mowner); 383 MOWNER_ATTACH(&tcp_rx_mowner); 384 MOWNER_ATTACH(&tcp_mowner); 385 } 386 387 /* 388 * Create template to be used to send tcp packets on a connection. 389 * Call after host entry created, allocates an mbuf and fills 390 * in a skeletal tcp/ip header, minimizing the amount of work 391 * necessary when the connection is used. 392 */ 393 struct mbuf * 394 tcp_template(struct tcpcb *tp) 395 { 396 struct inpcb *inp = tp->t_inpcb; 397 #ifdef INET6 398 struct in6pcb *in6p = tp->t_in6pcb; 399 #endif 400 struct tcphdr *n; 401 struct mbuf *m; 402 int hlen; 403 404 switch (tp->t_family) { 405 case AF_INET: 406 hlen = sizeof(struct ip); 407 if (inp) 408 break; 409 #ifdef INET6 410 if (in6p) { 411 /* mapped addr case */ 412 if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_laddr) 413 && IN6_IS_ADDR_V4MAPPED(&in6p->in6p_faddr)) 414 break; 415 } 416 #endif 417 return NULL; /*EINVAL*/ 418 #ifdef INET6 419 case AF_INET6: 420 hlen = sizeof(struct ip6_hdr); 421 if (in6p) { 422 /* more sainty check? */ 423 break; 424 } 425 return NULL; /*EINVAL*/ 426 #endif 427 default: 428 hlen = 0; /*pacify gcc*/ 429 return NULL; /*EAFNOSUPPORT*/ 430 } 431 #ifdef DIAGNOSTIC 432 if (hlen + sizeof(struct tcphdr) > MCLBYTES) 433 panic("mclbytes too small for t_template"); 434 #endif 435 m = tp->t_template; 436 if (m && m->m_len == hlen + sizeof(struct tcphdr)) 437 ; 438 else { 439 if (m) 440 m_freem(m); 441 m = tp->t_template = NULL; 442 MGETHDR(m, M_DONTWAIT, MT_HEADER); 443 if (m && hlen + sizeof(struct tcphdr) > MHLEN) { 444 MCLGET(m, M_DONTWAIT); 445 if ((m->m_flags & M_EXT) == 0) { 446 m_free(m); 447 m = NULL; 448 } 449 } 450 if (m == NULL) 451 return NULL; 452 MCLAIM(m, &tcp_mowner); 453 m->m_pkthdr.len = m->m_len = hlen + sizeof(struct tcphdr); 454 } 455 456 bzero(mtod(m, caddr_t), m->m_len); 457 458 n = (struct tcphdr *)(mtod(m, caddr_t) + hlen); 459 460 switch (tp->t_family) { 461 case AF_INET: 462 { 463 struct ipovly *ipov; 464 mtod(m, struct ip *)->ip_v = 4; 465 mtod(m, struct ip *)->ip_hl = hlen >> 2; 466 ipov = mtod(m, struct ipovly *); 467 ipov->ih_pr = IPPROTO_TCP; 468 ipov->ih_len = htons(sizeof(struct tcphdr)); 469 if (inp) { 470 ipov->ih_src = inp->inp_laddr; 471 ipov->ih_dst = inp->inp_faddr; 472 } 473 #ifdef INET6 474 else if (in6p) { 475 /* mapped addr case */ 476 bcopy(&in6p->in6p_laddr.s6_addr32[3], &ipov->ih_src, 477 sizeof(ipov->ih_src)); 478 bcopy(&in6p->in6p_faddr.s6_addr32[3], &ipov->ih_dst, 479 sizeof(ipov->ih_dst)); 480 } 481 #endif 482 /* 483 * Compute the pseudo-header portion of the checksum 484 * now. We incrementally add in the TCP option and 485 * payload lengths later, and then compute the TCP 486 * checksum right before the packet is sent off onto 487 * the wire. 488 */ 489 n->th_sum = in_cksum_phdr(ipov->ih_src.s_addr, 490 ipov->ih_dst.s_addr, 491 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 492 break; 493 } 494 #ifdef INET6 495 case AF_INET6: 496 { 497 struct ip6_hdr *ip6; 498 mtod(m, struct ip *)->ip_v = 6; 499 ip6 = mtod(m, struct ip6_hdr *); 500 ip6->ip6_nxt = IPPROTO_TCP; 501 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 502 ip6->ip6_src = in6p->in6p_laddr; 503 ip6->ip6_dst = in6p->in6p_faddr; 504 ip6->ip6_flow = in6p->in6p_flowinfo & IPV6_FLOWINFO_MASK; 505 if (ip6_auto_flowlabel) { 506 ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK; 507 ip6->ip6_flow |= 508 (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK); 509 } 510 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 511 ip6->ip6_vfc |= IPV6_VERSION; 512 513 /* 514 * Compute the pseudo-header portion of the checksum 515 * now. We incrementally add in the TCP option and 516 * payload lengths later, and then compute the TCP 517 * checksum right before the packet is sent off onto 518 * the wire. 519 */ 520 n->th_sum = in6_cksum_phdr(&in6p->in6p_laddr, 521 &in6p->in6p_faddr, htonl(sizeof(struct tcphdr)), 522 htonl(IPPROTO_TCP)); 523 break; 524 } 525 #endif 526 } 527 if (inp) { 528 n->th_sport = inp->inp_lport; 529 n->th_dport = inp->inp_fport; 530 } 531 #ifdef INET6 532 else if (in6p) { 533 n->th_sport = in6p->in6p_lport; 534 n->th_dport = in6p->in6p_fport; 535 } 536 #endif 537 n->th_seq = 0; 538 n->th_ack = 0; 539 n->th_x2 = 0; 540 n->th_off = 5; 541 n->th_flags = 0; 542 n->th_win = 0; 543 n->th_urp = 0; 544 return (m); 545 } 546 547 /* 548 * Send a single message to the TCP at address specified by 549 * the given TCP/IP header. If m == 0, then we make a copy 550 * of the tcpiphdr at ti and send directly to the addressed host. 551 * This is used to force keep alive messages out using the TCP 552 * template for a connection tp->t_template. If flags are given 553 * then we send a message back to the TCP which originated the 554 * segment ti, and discard the mbuf containing it and any other 555 * attached mbufs. 556 * 557 * In any case the ack and sequence number of the transmitted 558 * segment are as specified by the parameters. 559 */ 560 int 561 tcp_respond(struct tcpcb *tp, struct mbuf *template, struct mbuf *m, 562 struct tcphdr *th0, tcp_seq ack, tcp_seq seq, int flags) 563 { 564 struct route *ro; 565 int error, tlen, win = 0; 566 int hlen; 567 struct ip *ip; 568 #ifdef INET6 569 struct ip6_hdr *ip6; 570 #endif 571 int family; /* family on packet, not inpcb/in6pcb! */ 572 struct tcphdr *th; 573 struct socket *so; 574 575 if (tp != NULL && (flags & TH_RST) == 0) { 576 #ifdef DIAGNOSTIC 577 if (tp->t_inpcb && tp->t_in6pcb) 578 panic("tcp_respond: both t_inpcb and t_in6pcb are set"); 579 #endif 580 #ifdef INET 581 if (tp->t_inpcb) 582 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 583 #endif 584 #ifdef INET6 585 if (tp->t_in6pcb) 586 win = sbspace(&tp->t_in6pcb->in6p_socket->so_rcv); 587 #endif 588 } 589 590 th = NULL; /* Quell uninitialized warning */ 591 ip = NULL; 592 #ifdef INET6 593 ip6 = NULL; 594 #endif 595 if (m == 0) { 596 if (!template) 597 return EINVAL; 598 599 /* get family information from template */ 600 switch (mtod(template, struct ip *)->ip_v) { 601 case 4: 602 family = AF_INET; 603 hlen = sizeof(struct ip); 604 break; 605 #ifdef INET6 606 case 6: 607 family = AF_INET6; 608 hlen = sizeof(struct ip6_hdr); 609 break; 610 #endif 611 default: 612 return EAFNOSUPPORT; 613 } 614 615 MGETHDR(m, M_DONTWAIT, MT_HEADER); 616 if (m) { 617 MCLAIM(m, &tcp_tx_mowner); 618 MCLGET(m, M_DONTWAIT); 619 if ((m->m_flags & M_EXT) == 0) { 620 m_free(m); 621 m = NULL; 622 } 623 } 624 if (m == NULL) 625 return (ENOBUFS); 626 627 if (tcp_compat_42) 628 tlen = 1; 629 else 630 tlen = 0; 631 632 m->m_data += max_linkhdr; 633 bcopy(mtod(template, caddr_t), mtod(m, caddr_t), 634 template->m_len); 635 switch (family) { 636 case AF_INET: 637 ip = mtod(m, struct ip *); 638 th = (struct tcphdr *)(ip + 1); 639 break; 640 #ifdef INET6 641 case AF_INET6: 642 ip6 = mtod(m, struct ip6_hdr *); 643 th = (struct tcphdr *)(ip6 + 1); 644 break; 645 #endif 646 #if 0 647 default: 648 /* noone will visit here */ 649 m_freem(m); 650 return EAFNOSUPPORT; 651 #endif 652 } 653 flags = TH_ACK; 654 } else { 655 656 if ((m->m_flags & M_PKTHDR) == 0) { 657 #if 0 658 printf("non PKTHDR to tcp_respond\n"); 659 #endif 660 m_freem(m); 661 return EINVAL; 662 } 663 #ifdef DIAGNOSTIC 664 if (!th0) 665 panic("th0 == NULL in tcp_respond"); 666 #endif 667 668 /* get family information from m */ 669 switch (mtod(m, struct ip *)->ip_v) { 670 case 4: 671 family = AF_INET; 672 hlen = sizeof(struct ip); 673 ip = mtod(m, struct ip *); 674 break; 675 #ifdef INET6 676 case 6: 677 family = AF_INET6; 678 hlen = sizeof(struct ip6_hdr); 679 ip6 = mtod(m, struct ip6_hdr *); 680 break; 681 #endif 682 default: 683 m_freem(m); 684 return EAFNOSUPPORT; 685 } 686 /* clear h/w csum flags inherited from rx packet */ 687 m->m_pkthdr.csum_flags = 0; 688 689 if ((flags & TH_SYN) == 0 || sizeof(*th0) > (th0->th_off << 2)) 690 tlen = sizeof(*th0); 691 else 692 tlen = th0->th_off << 2; 693 694 if (m->m_len > hlen + tlen && (m->m_flags & M_EXT) == 0 && 695 mtod(m, caddr_t) + hlen == (caddr_t)th0) { 696 m->m_len = hlen + tlen; 697 m_freem(m->m_next); 698 m->m_next = NULL; 699 } else { 700 struct mbuf *n; 701 702 #ifdef DIAGNOSTIC 703 if (max_linkhdr + hlen + tlen > MCLBYTES) { 704 m_freem(m); 705 return EMSGSIZE; 706 } 707 #endif 708 MGETHDR(n, M_DONTWAIT, MT_HEADER); 709 if (n && max_linkhdr + hlen + tlen > MHLEN) { 710 MCLGET(n, M_DONTWAIT); 711 if ((n->m_flags & M_EXT) == 0) { 712 m_freem(n); 713 n = NULL; 714 } 715 } 716 if (!n) { 717 m_freem(m); 718 return ENOBUFS; 719 } 720 721 MCLAIM(n, &tcp_tx_mowner); 722 n->m_data += max_linkhdr; 723 n->m_len = hlen + tlen; 724 m_copyback(n, 0, hlen, mtod(m, caddr_t)); 725 m_copyback(n, hlen, tlen, (caddr_t)th0); 726 727 m_freem(m); 728 m = n; 729 n = NULL; 730 } 731 732 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 733 switch (family) { 734 case AF_INET: 735 ip = mtod(m, struct ip *); 736 th = (struct tcphdr *)(ip + 1); 737 ip->ip_p = IPPROTO_TCP; 738 xchg(ip->ip_dst, ip->ip_src, struct in_addr); 739 ip->ip_p = IPPROTO_TCP; 740 break; 741 #ifdef INET6 742 case AF_INET6: 743 ip6 = mtod(m, struct ip6_hdr *); 744 th = (struct tcphdr *)(ip6 + 1); 745 ip6->ip6_nxt = IPPROTO_TCP; 746 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 747 ip6->ip6_nxt = IPPROTO_TCP; 748 break; 749 #endif 750 #if 0 751 default: 752 /* noone will visit here */ 753 m_freem(m); 754 return EAFNOSUPPORT; 755 #endif 756 } 757 xchg(th->th_dport, th->th_sport, u_int16_t); 758 #undef xchg 759 tlen = 0; /*be friendly with the following code*/ 760 } 761 th->th_seq = htonl(seq); 762 th->th_ack = htonl(ack); 763 th->th_x2 = 0; 764 if ((flags & TH_SYN) == 0) { 765 if (tp) 766 win >>= tp->rcv_scale; 767 if (win > TCP_MAXWIN) 768 win = TCP_MAXWIN; 769 th->th_win = htons((u_int16_t)win); 770 th->th_off = sizeof (struct tcphdr) >> 2; 771 tlen += sizeof(*th); 772 } else 773 tlen += th->th_off << 2; 774 m->m_len = hlen + tlen; 775 m->m_pkthdr.len = hlen + tlen; 776 m->m_pkthdr.rcvif = (struct ifnet *) 0; 777 th->th_flags = flags; 778 th->th_urp = 0; 779 780 switch (family) { 781 #ifdef INET 782 case AF_INET: 783 { 784 struct ipovly *ipov = (struct ipovly *)ip; 785 bzero(ipov->ih_x1, sizeof ipov->ih_x1); 786 ipov->ih_len = htons((u_int16_t)tlen); 787 788 th->th_sum = 0; 789 th->th_sum = in_cksum(m, hlen + tlen); 790 ip->ip_len = htons(hlen + tlen); 791 ip->ip_ttl = ip_defttl; 792 break; 793 } 794 #endif 795 #ifdef INET6 796 case AF_INET6: 797 { 798 th->th_sum = 0; 799 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), 800 tlen); 801 ip6->ip6_plen = htons(tlen); 802 if (tp && tp->t_in6pcb) { 803 struct ifnet *oifp; 804 ro = (struct route *)&tp->t_in6pcb->in6p_route; 805 oifp = ro->ro_rt ? ro->ro_rt->rt_ifp : NULL; 806 ip6->ip6_hlim = in6_selecthlim(tp->t_in6pcb, oifp); 807 } else 808 ip6->ip6_hlim = ip6_defhlim; 809 ip6->ip6_flow &= ~IPV6_FLOWINFO_MASK; 810 if (ip6_auto_flowlabel) { 811 ip6->ip6_flow |= 812 (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK); 813 } 814 break; 815 } 816 #endif 817 } 818 819 if (tp && tp->t_inpcb) 820 so = tp->t_inpcb->inp_socket; 821 #ifdef INET6 822 else if (tp && tp->t_in6pcb) 823 so = tp->t_in6pcb->in6p_socket; 824 #endif 825 else 826 so = NULL; 827 828 if (tp != NULL && tp->t_inpcb != NULL) { 829 ro = &tp->t_inpcb->inp_route; 830 #ifdef DIAGNOSTIC 831 if (family != AF_INET) 832 panic("tcp_respond: address family mismatch"); 833 if (!in_hosteq(ip->ip_dst, tp->t_inpcb->inp_faddr)) { 834 panic("tcp_respond: ip_dst %x != inp_faddr %x", 835 ntohl(ip->ip_dst.s_addr), 836 ntohl(tp->t_inpcb->inp_faddr.s_addr)); 837 } 838 #endif 839 } 840 #ifdef INET6 841 else if (tp != NULL && tp->t_in6pcb != NULL) { 842 ro = (struct route *)&tp->t_in6pcb->in6p_route; 843 #ifdef DIAGNOSTIC 844 if (family == AF_INET) { 845 if (!IN6_IS_ADDR_V4MAPPED(&tp->t_in6pcb->in6p_faddr)) 846 panic("tcp_respond: not mapped addr"); 847 if (bcmp(&ip->ip_dst, 848 &tp->t_in6pcb->in6p_faddr.s6_addr32[3], 849 sizeof(ip->ip_dst)) != 0) { 850 panic("tcp_respond: ip_dst != in6p_faddr"); 851 } 852 } else if (family == AF_INET6) { 853 if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, 854 &tp->t_in6pcb->in6p_faddr)) 855 panic("tcp_respond: ip6_dst != in6p_faddr"); 856 } else 857 panic("tcp_respond: address family mismatch"); 858 #endif 859 } 860 #endif 861 else 862 ro = NULL; 863 864 switch (family) { 865 #ifdef INET 866 case AF_INET: 867 error = ip_output(m, NULL, ro, 868 (tp && tp->t_mtudisc ? IP_MTUDISC : 0), 869 (struct ip_moptions *)0, so); 870 break; 871 #endif 872 #ifdef INET6 873 case AF_INET6: 874 error = ip6_output(m, NULL, (struct route_in6 *)ro, 0, 875 (struct ip6_moptions *)0, so, NULL); 876 break; 877 #endif 878 default: 879 error = EAFNOSUPPORT; 880 break; 881 } 882 883 return (error); 884 } 885 886 /* 887 * Template TCPCB. Rather than zeroing a new TCPCB and initializing 888 * a bunch of members individually, we maintain this template for the 889 * static and mostly-static components of the TCPCB, and copy it into 890 * the new TCPCB instead. 891 */ 892 static struct tcpcb tcpcb_template = { 893 /* 894 * If TCP_NTIMERS ever changes, we'll need to update this 895 * initializer. 896 */ 897 .t_timer = { 898 CALLOUT_INITIALIZER, 899 CALLOUT_INITIALIZER, 900 CALLOUT_INITIALIZER, 901 CALLOUT_INITIALIZER, 902 }, 903 .t_delack_ch = CALLOUT_INITIALIZER, 904 905 .t_srtt = TCPTV_SRTTBASE, 906 .t_rttmin = TCPTV_MIN, 907 908 .snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT, 909 .snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT, 910 }; 911 912 /* 913 * Updates the TCPCB template whenever a parameter that would affect 914 * the template is changed. 915 */ 916 void 917 tcp_tcpcb_template(void) 918 { 919 struct tcpcb *tp = &tcpcb_template; 920 int flags; 921 922 tp->t_peermss = tcp_mssdflt; 923 tp->t_ourmss = tcp_mssdflt; 924 tp->t_segsz = tcp_mssdflt; 925 926 flags = 0; 927 if (tcp_do_rfc1323 && tcp_do_win_scale) 928 flags |= TF_REQ_SCALE; 929 if (tcp_do_rfc1323 && tcp_do_timestamps) 930 flags |= TF_REQ_TSTMP; 931 if (tcp_do_sack == 2) 932 flags |= TF_WILL_SACK; 933 else if (tcp_do_sack == 1) 934 flags |= TF_WILL_SACK|TF_IGNR_RXSACK; 935 flags |= TF_CANT_TXSACK; 936 tp->t_flags = flags; 937 938 /* 939 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 940 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 941 * reasonable initial retransmit time. 942 */ 943 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1); 944 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 945 TCPTV_MIN, TCPTV_REXMTMAX); 946 } 947 948 /* 949 * Create a new TCP control block, making an 950 * empty reassembly queue and hooking it to the argument 951 * protocol control block. 952 */ 953 /* family selects inpcb, or in6pcb */ 954 struct tcpcb * 955 tcp_newtcpcb(int family, void *aux) 956 { 957 struct tcpcb *tp; 958 int i; 959 960 /* XXX Consider using a pool_cache for speed. */ 961 tp = pool_get(&tcpcb_pool, PR_NOWAIT); 962 if (tp == NULL) 963 return (NULL); 964 memcpy(tp, &tcpcb_template, sizeof(*tp)); 965 TAILQ_INIT(&tp->segq); 966 TAILQ_INIT(&tp->timeq); 967 tp->t_family = family; /* may be overridden later on */ 968 LIST_INIT(&tp->t_sc); /* XXX can template this */ 969 970 /* Don't sweat this loop; hopefully the compiler will unroll it. */ 971 for (i = 0; i < TCPT_NTIMERS; i++) 972 TCP_TIMER_INIT(tp, i); 973 974 switch (family) { 975 case AF_INET: 976 { 977 struct inpcb *inp = (struct inpcb *)aux; 978 979 inp->inp_ip.ip_ttl = ip_defttl; 980 inp->inp_ppcb = (caddr_t)tp; 981 982 tp->t_inpcb = inp; 983 tp->t_mtudisc = ip_mtudisc; 984 break; 985 } 986 #ifdef INET6 987 case AF_INET6: 988 { 989 struct in6pcb *in6p = (struct in6pcb *)aux; 990 991 in6p->in6p_ip6.ip6_hlim = in6_selecthlim(in6p, 992 in6p->in6p_route.ro_rt ? in6p->in6p_route.ro_rt->rt_ifp 993 : NULL); 994 in6p->in6p_ppcb = (caddr_t)tp; 995 996 tp->t_in6pcb = in6p; 997 /* for IPv6, always try to run path MTU discovery */ 998 tp->t_mtudisc = 1; 999 break; 1000 } 1001 #endif /* INET6 */ 1002 default: 1003 pool_put(&tcpcb_pool, tp); 1004 return (NULL); 1005 } 1006 1007 /* 1008 * Initialize our timebase. When we send timestamps, we take 1009 * the delta from tcp_now -- this means each connection always 1010 * gets a timebase of 0, which makes it, among other things, 1011 * more difficult to determine how long a system has been up, 1012 * and thus how many TCP sequence increments have occurred. 1013 */ 1014 tp->ts_timebase = tcp_now; 1015 1016 return (tp); 1017 } 1018 1019 /* 1020 * Drop a TCP connection, reporting 1021 * the specified error. If connection is synchronized, 1022 * then send a RST to peer. 1023 */ 1024 struct tcpcb * 1025 tcp_drop(struct tcpcb *tp, int errno) 1026 { 1027 struct socket *so = NULL; 1028 1029 #ifdef DIAGNOSTIC 1030 if (tp->t_inpcb && tp->t_in6pcb) 1031 panic("tcp_drop: both t_inpcb and t_in6pcb are set"); 1032 #endif 1033 #ifdef INET 1034 if (tp->t_inpcb) 1035 so = tp->t_inpcb->inp_socket; 1036 #endif 1037 #ifdef INET6 1038 if (tp->t_in6pcb) 1039 so = tp->t_in6pcb->in6p_socket; 1040 #endif 1041 if (!so) 1042 return NULL; 1043 1044 if (TCPS_HAVERCVDSYN(tp->t_state)) { 1045 tp->t_state = TCPS_CLOSED; 1046 (void) tcp_output(tp); 1047 tcpstat.tcps_drops++; 1048 } else 1049 tcpstat.tcps_conndrops++; 1050 if (errno == ETIMEDOUT && tp->t_softerror) 1051 errno = tp->t_softerror; 1052 so->so_error = errno; 1053 return (tcp_close(tp)); 1054 } 1055 1056 /* 1057 * Return whether this tcpcb is marked as dead, indicating 1058 * to the calling timer function that no further action should 1059 * be taken, as we are about to release this tcpcb. The release 1060 * of the storage will be done if this is the last timer running. 1061 * 1062 * This should be called from the callout handler function after 1063 * callout_ack() is done, so that the number of invoking timer 1064 * functions is 0. 1065 */ 1066 int 1067 tcp_isdead(struct tcpcb *tp) 1068 { 1069 int dead = (tp->t_flags & TF_DEAD); 1070 1071 if (__predict_false(dead)) { 1072 if (tcp_timers_invoking(tp) > 0) 1073 /* not quite there yet -- count separately? */ 1074 return dead; 1075 tcpstat.tcps_delayed_free++; 1076 pool_put(&tcpcb_pool, tp); 1077 } 1078 return dead; 1079 } 1080 1081 /* 1082 * Close a TCP control block: 1083 * discard all space held by the tcp 1084 * discard internet protocol block 1085 * wake up any sleepers 1086 */ 1087 struct tcpcb * 1088 tcp_close(struct tcpcb *tp) 1089 { 1090 struct inpcb *inp; 1091 #ifdef INET6 1092 struct in6pcb *in6p; 1093 #endif 1094 struct socket *so; 1095 #ifdef RTV_RTT 1096 struct rtentry *rt; 1097 #endif 1098 struct route *ro; 1099 1100 inp = tp->t_inpcb; 1101 #ifdef INET6 1102 in6p = tp->t_in6pcb; 1103 #endif 1104 so = NULL; 1105 ro = NULL; 1106 if (inp) { 1107 so = inp->inp_socket; 1108 ro = &inp->inp_route; 1109 } 1110 #ifdef INET6 1111 else if (in6p) { 1112 so = in6p->in6p_socket; 1113 ro = (struct route *)&in6p->in6p_route; 1114 } 1115 #endif 1116 1117 #ifdef RTV_RTT 1118 /* 1119 * If we sent enough data to get some meaningful characteristics, 1120 * save them in the routing entry. 'Enough' is arbitrarily 1121 * defined as the sendpipesize (default 4K) * 16. This would 1122 * give us 16 rtt samples assuming we only get one sample per 1123 * window (the usual case on a long haul net). 16 samples is 1124 * enough for the srtt filter to converge to within 5% of the correct 1125 * value; fewer samples and we could save a very bogus rtt. 1126 * 1127 * Don't update the default route's characteristics and don't 1128 * update anything that the user "locked". 1129 */ 1130 if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) && 1131 ro && (rt = ro->ro_rt) && 1132 !in_nullhost(satosin(rt_key(rt))->sin_addr)) { 1133 u_long i = 0; 1134 1135 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 1136 i = tp->t_srtt * 1137 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1138 if (rt->rt_rmx.rmx_rtt && i) 1139 /* 1140 * filter this update to half the old & half 1141 * the new values, converting scale. 1142 * See route.h and tcp_var.h for a 1143 * description of the scaling constants. 1144 */ 1145 rt->rt_rmx.rmx_rtt = 1146 (rt->rt_rmx.rmx_rtt + i) / 2; 1147 else 1148 rt->rt_rmx.rmx_rtt = i; 1149 } 1150 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 1151 i = tp->t_rttvar * 1152 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2)); 1153 if (rt->rt_rmx.rmx_rttvar && i) 1154 rt->rt_rmx.rmx_rttvar = 1155 (rt->rt_rmx.rmx_rttvar + i) / 2; 1156 else 1157 rt->rt_rmx.rmx_rttvar = i; 1158 } 1159 /* 1160 * update the pipelimit (ssthresh) if it has been updated 1161 * already or if a pipesize was specified & the threshhold 1162 * got below half the pipesize. I.e., wait for bad news 1163 * before we start updating, then update on both good 1164 * and bad news. 1165 */ 1166 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 1167 (i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) || 1168 i < (rt->rt_rmx.rmx_sendpipe / 2)) { 1169 /* 1170 * convert the limit from user data bytes to 1171 * packets then to packet data bytes. 1172 */ 1173 i = (i + tp->t_segsz / 2) / tp->t_segsz; 1174 if (i < 2) 1175 i = 2; 1176 i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr)); 1177 if (rt->rt_rmx.rmx_ssthresh) 1178 rt->rt_rmx.rmx_ssthresh = 1179 (rt->rt_rmx.rmx_ssthresh + i) / 2; 1180 else 1181 rt->rt_rmx.rmx_ssthresh = i; 1182 } 1183 } 1184 #endif /* RTV_RTT */ 1185 /* free the reassembly queue, if any */ 1186 TCP_REASS_LOCK(tp); 1187 (void) tcp_freeq(tp); 1188 TCP_REASS_UNLOCK(tp); 1189 1190 tcp_canceltimers(tp); 1191 TCP_CLEAR_DELACK(tp); 1192 syn_cache_cleanup(tp); 1193 1194 if (tp->t_template) { 1195 m_free(tp->t_template); 1196 tp->t_template = NULL; 1197 } 1198 if (tcp_timers_invoking(tp)) 1199 tp->t_flags |= TF_DEAD; 1200 else 1201 pool_put(&tcpcb_pool, tp); 1202 1203 if (inp) { 1204 inp->inp_ppcb = 0; 1205 soisdisconnected(so); 1206 in_pcbdetach(inp); 1207 } 1208 #ifdef INET6 1209 else if (in6p) { 1210 in6p->in6p_ppcb = 0; 1211 soisdisconnected(so); 1212 in6_pcbdetach(in6p); 1213 } 1214 #endif 1215 tcpstat.tcps_closed++; 1216 return ((struct tcpcb *)0); 1217 } 1218 1219 int 1220 tcp_freeq(tp) 1221 struct tcpcb *tp; 1222 { 1223 struct ipqent *qe; 1224 int rv = 0; 1225 #ifdef TCPREASS_DEBUG 1226 int i = 0; 1227 #endif 1228 1229 TCP_REASS_LOCK_CHECK(tp); 1230 1231 while ((qe = TAILQ_FIRST(&tp->segq)) != NULL) { 1232 #ifdef TCPREASS_DEBUG 1233 printf("tcp_freeq[%p,%d]: %u:%u(%u) 0x%02x\n", 1234 tp, i++, qe->ipqe_seq, qe->ipqe_seq + qe->ipqe_len, 1235 qe->ipqe_len, qe->ipqe_flags & (TH_SYN|TH_FIN|TH_RST)); 1236 #endif 1237 TAILQ_REMOVE(&tp->segq, qe, ipqe_q); 1238 TAILQ_REMOVE(&tp->timeq, qe, ipqe_timeq); 1239 m_freem(qe->ipqe_m); 1240 pool_put(&tcpipqent_pool, qe); 1241 rv = 1; 1242 } 1243 return (rv); 1244 } 1245 1246 /* 1247 * Protocol drain routine. Called when memory is in short supply. 1248 */ 1249 void 1250 tcp_drain(void) 1251 { 1252 struct inpcb_hdr *inph; 1253 struct tcpcb *tp; 1254 1255 /* 1256 * Free the sequence queue of all TCP connections. 1257 */ 1258 CIRCLEQ_FOREACH(inph, &tcbtable.inpt_queue, inph_queue) { 1259 switch (inph->inph_af) { 1260 case AF_INET: 1261 tp = intotcpcb((struct inpcb *)inph); 1262 break; 1263 #ifdef INET6 1264 case AF_INET6: 1265 tp = in6totcpcb((struct in6pcb *)inph); 1266 break; 1267 #endif 1268 default: 1269 tp = NULL; 1270 break; 1271 } 1272 if (tp != NULL) { 1273 /* 1274 * We may be called from a device's interrupt 1275 * context. If the tcpcb is already busy, 1276 * just bail out now. 1277 */ 1278 if (tcp_reass_lock_try(tp) == 0) 1279 continue; 1280 if (tcp_freeq(tp)) 1281 tcpstat.tcps_connsdrained++; 1282 TCP_REASS_UNLOCK(tp); 1283 } 1284 } 1285 } 1286 1287 /* 1288 * Notify a tcp user of an asynchronous error; 1289 * store error as soft error, but wake up user 1290 * (for now, won't do anything until can select for soft error). 1291 */ 1292 void 1293 tcp_notify(struct inpcb *inp, int error) 1294 { 1295 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 1296 struct socket *so = inp->inp_socket; 1297 1298 /* 1299 * Ignore some errors if we are hooked up. 1300 * If connection hasn't completed, has retransmitted several times, 1301 * and receives a second error, give up now. This is better 1302 * than waiting a long time to establish a connection that 1303 * can never complete. 1304 */ 1305 if (tp->t_state == TCPS_ESTABLISHED && 1306 (error == EHOSTUNREACH || error == ENETUNREACH || 1307 error == EHOSTDOWN)) { 1308 return; 1309 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1310 tp->t_rxtshift > 3 && tp->t_softerror) 1311 so->so_error = error; 1312 else 1313 tp->t_softerror = error; 1314 wakeup((caddr_t) &so->so_timeo); 1315 sorwakeup(so); 1316 sowwakeup(so); 1317 } 1318 1319 #ifdef INET6 1320 void 1321 tcp6_notify(struct in6pcb *in6p, int error) 1322 { 1323 struct tcpcb *tp = (struct tcpcb *)in6p->in6p_ppcb; 1324 struct socket *so = in6p->in6p_socket; 1325 1326 /* 1327 * Ignore some errors if we are hooked up. 1328 * If connection hasn't completed, has retransmitted several times, 1329 * and receives a second error, give up now. This is better 1330 * than waiting a long time to establish a connection that 1331 * can never complete. 1332 */ 1333 if (tp->t_state == TCPS_ESTABLISHED && 1334 (error == EHOSTUNREACH || error == ENETUNREACH || 1335 error == EHOSTDOWN)) { 1336 return; 1337 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1338 tp->t_rxtshift > 3 && tp->t_softerror) 1339 so->so_error = error; 1340 else 1341 tp->t_softerror = error; 1342 wakeup((caddr_t) &so->so_timeo); 1343 sorwakeup(so); 1344 sowwakeup(so); 1345 } 1346 #endif 1347 1348 #ifdef INET6 1349 void 1350 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1351 { 1352 struct tcphdr th; 1353 void (*notify)(struct in6pcb *, int) = tcp6_notify; 1354 int nmatch; 1355 struct ip6_hdr *ip6; 1356 const struct sockaddr_in6 *sa6_src = NULL; 1357 struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)sa; 1358 struct mbuf *m; 1359 int off; 1360 1361 if (sa->sa_family != AF_INET6 || 1362 sa->sa_len != sizeof(struct sockaddr_in6)) 1363 return; 1364 if ((unsigned)cmd >= PRC_NCMDS) 1365 return; 1366 else if (cmd == PRC_QUENCH) { 1367 /* XXX there's no PRC_QUENCH in IPv6 */ 1368 notify = tcp6_quench; 1369 } else if (PRC_IS_REDIRECT(cmd)) 1370 notify = in6_rtchange, d = NULL; 1371 else if (cmd == PRC_MSGSIZE) 1372 ; /* special code is present, see below */ 1373 else if (cmd == PRC_HOSTDEAD) 1374 d = NULL; 1375 else if (inet6ctlerrmap[cmd] == 0) 1376 return; 1377 1378 /* if the parameter is from icmp6, decode it. */ 1379 if (d != NULL) { 1380 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 1381 m = ip6cp->ip6c_m; 1382 ip6 = ip6cp->ip6c_ip6; 1383 off = ip6cp->ip6c_off; 1384 sa6_src = ip6cp->ip6c_src; 1385 } else { 1386 m = NULL; 1387 ip6 = NULL; 1388 sa6_src = &sa6_any; 1389 off = 0; 1390 } 1391 1392 if (ip6) { 1393 /* 1394 * XXX: We assume that when ip6 is non NULL, 1395 * M and OFF are valid. 1396 */ 1397 1398 /* check if we can safely examine src and dst ports */ 1399 if (m->m_pkthdr.len < off + sizeof(th)) { 1400 if (cmd == PRC_MSGSIZE) 1401 icmp6_mtudisc_update((struct ip6ctlparam *)d, 0); 1402 return; 1403 } 1404 1405 bzero(&th, sizeof(th)); 1406 m_copydata(m, off, sizeof(th), (caddr_t)&th); 1407 1408 if (cmd == PRC_MSGSIZE) { 1409 int valid = 0; 1410 1411 /* 1412 * Check to see if we have a valid TCP connection 1413 * corresponding to the address in the ICMPv6 message 1414 * payload. 1415 */ 1416 if (in6_pcblookup_connect(&tcbtable, &sa6->sin6_addr, 1417 th.th_dport, (struct in6_addr *)&sa6_src->sin6_addr, 1418 th.th_sport, 0)) 1419 valid++; 1420 1421 /* 1422 * Depending on the value of "valid" and routing table 1423 * size (mtudisc_{hi,lo}wat), we will: 1424 * - recalcurate the new MTU and create the 1425 * corresponding routing entry, or 1426 * - ignore the MTU change notification. 1427 */ 1428 icmp6_mtudisc_update((struct ip6ctlparam *)d, valid); 1429 1430 /* 1431 * no need to call in6_pcbnotify, it should have been 1432 * called via callback if necessary 1433 */ 1434 return; 1435 } 1436 1437 nmatch = in6_pcbnotify(&tcbtable, sa, th.th_dport, 1438 (struct sockaddr *)sa6_src, th.th_sport, cmd, NULL, notify); 1439 if (nmatch == 0 && syn_cache_count && 1440 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 1441 inet6ctlerrmap[cmd] == ENETUNREACH || 1442 inet6ctlerrmap[cmd] == EHOSTDOWN)) 1443 syn_cache_unreach((struct sockaddr *)sa6_src, 1444 sa, &th); 1445 } else { 1446 (void) in6_pcbnotify(&tcbtable, sa, 0, 1447 (struct sockaddr *)sa6_src, 0, cmd, NULL, notify); 1448 } 1449 } 1450 #endif 1451 1452 #ifdef INET 1453 /* assumes that ip header and tcp header are contiguous on mbuf */ 1454 void * 1455 tcp_ctlinput(int cmd, struct sockaddr *sa, void *v) 1456 { 1457 struct ip *ip = v; 1458 struct tcphdr *th; 1459 struct icmp *icp; 1460 extern const int inetctlerrmap[]; 1461 void (*notify)(struct inpcb *, int) = tcp_notify; 1462 int errno; 1463 int nmatch; 1464 #ifdef INET6 1465 struct in6_addr src6, dst6; 1466 #endif 1467 1468 if (sa->sa_family != AF_INET || 1469 sa->sa_len != sizeof(struct sockaddr_in)) 1470 return NULL; 1471 if ((unsigned)cmd >= PRC_NCMDS) 1472 return NULL; 1473 errno = inetctlerrmap[cmd]; 1474 if (cmd == PRC_QUENCH) 1475 notify = tcp_quench; 1476 else if (PRC_IS_REDIRECT(cmd)) 1477 notify = in_rtchange, ip = 0; 1478 else if (cmd == PRC_MSGSIZE && ip && ip->ip_v == 4) { 1479 /* 1480 * Check to see if we have a valid TCP connection 1481 * corresponding to the address in the ICMP message 1482 * payload. 1483 * 1484 * Boundary check is made in icmp_input(), with ICMP_ADVLENMIN. 1485 */ 1486 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1487 #ifdef INET6 1488 memset(&src6, 0, sizeof(src6)); 1489 memset(&dst6, 0, sizeof(dst6)); 1490 src6.s6_addr16[5] = dst6.s6_addr16[5] = 0xffff; 1491 memcpy(&src6.s6_addr32[3], &ip->ip_src, sizeof(struct in_addr)); 1492 memcpy(&dst6.s6_addr32[3], &ip->ip_dst, sizeof(struct in_addr)); 1493 #endif 1494 if (in_pcblookup_connect(&tcbtable, ip->ip_dst, th->th_dport, 1495 ip->ip_src, th->th_sport) != NULL) 1496 ; 1497 #ifdef INET6 1498 else if (in6_pcblookup_connect(&tcbtable, &dst6, 1499 th->th_dport, &src6, th->th_sport, 0) != NULL) 1500 ; 1501 #endif 1502 else 1503 return NULL; 1504 1505 /* 1506 * Now that we've validated that we are actually communicating 1507 * with the host indicated in the ICMP message, locate the 1508 * ICMP header, recalculate the new MTU, and create the 1509 * corresponding routing entry. 1510 */ 1511 icp = (struct icmp *)((caddr_t)ip - 1512 offsetof(struct icmp, icmp_ip)); 1513 icmp_mtudisc(icp, ip->ip_dst); 1514 1515 return NULL; 1516 } else if (cmd == PRC_HOSTDEAD) 1517 ip = 0; 1518 else if (errno == 0) 1519 return NULL; 1520 if (ip && ip->ip_v == 4 && sa->sa_family == AF_INET) { 1521 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1522 nmatch = in_pcbnotify(&tcbtable, satosin(sa)->sin_addr, 1523 th->th_dport, ip->ip_src, th->th_sport, errno, notify); 1524 if (nmatch == 0 && syn_cache_count && 1525 (inetctlerrmap[cmd] == EHOSTUNREACH || 1526 inetctlerrmap[cmd] == ENETUNREACH || 1527 inetctlerrmap[cmd] == EHOSTDOWN)) { 1528 struct sockaddr_in sin; 1529 bzero(&sin, sizeof(sin)); 1530 sin.sin_len = sizeof(sin); 1531 sin.sin_family = AF_INET; 1532 sin.sin_port = th->th_sport; 1533 sin.sin_addr = ip->ip_src; 1534 syn_cache_unreach((struct sockaddr *)&sin, sa, th); 1535 } 1536 1537 /* XXX mapped address case */ 1538 } else 1539 in_pcbnotifyall(&tcbtable, satosin(sa)->sin_addr, errno, 1540 notify); 1541 return NULL; 1542 } 1543 1544 /* 1545 * When a source quence is received, we are being notifed of congestion. 1546 * Close the congestion window down to the Loss Window (one segment). 1547 * We will gradually open it again as we proceed. 1548 */ 1549 void 1550 tcp_quench(struct inpcb *inp, int errno) 1551 { 1552 struct tcpcb *tp = intotcpcb(inp); 1553 1554 if (tp) 1555 tp->snd_cwnd = tp->t_segsz; 1556 } 1557 #endif 1558 1559 #ifdef INET6 1560 void 1561 tcp6_quench(struct in6pcb *in6p, int errno) 1562 { 1563 struct tcpcb *tp = in6totcpcb(in6p); 1564 1565 if (tp) 1566 tp->snd_cwnd = tp->t_segsz; 1567 } 1568 #endif 1569 1570 #ifdef INET 1571 /* 1572 * Path MTU Discovery handlers. 1573 */ 1574 void 1575 tcp_mtudisc_callback(struct in_addr faddr) 1576 { 1577 #ifdef INET6 1578 struct in6_addr in6; 1579 #endif 1580 1581 in_pcbnotifyall(&tcbtable, faddr, EMSGSIZE, tcp_mtudisc); 1582 #ifdef INET6 1583 memset(&in6, 0, sizeof(in6)); 1584 in6.s6_addr16[5] = 0xffff; 1585 memcpy(&in6.s6_addr32[3], &faddr, sizeof(struct in_addr)); 1586 tcp6_mtudisc_callback(&in6); 1587 #endif 1588 } 1589 1590 /* 1591 * On receipt of path MTU corrections, flush old route and replace it 1592 * with the new one. Retransmit all unacknowledged packets, to ensure 1593 * that all packets will be received. 1594 */ 1595 void 1596 tcp_mtudisc(struct inpcb *inp, int errno) 1597 { 1598 struct tcpcb *tp = intotcpcb(inp); 1599 struct rtentry *rt = in_pcbrtentry(inp); 1600 1601 if (tp != 0) { 1602 if (rt != 0) { 1603 /* 1604 * If this was not a host route, remove and realloc. 1605 */ 1606 if ((rt->rt_flags & RTF_HOST) == 0) { 1607 in_rtchange(inp, errno); 1608 if ((rt = in_pcbrtentry(inp)) == 0) 1609 return; 1610 } 1611 1612 /* 1613 * Slow start out of the error condition. We 1614 * use the MTU because we know it's smaller 1615 * than the previously transmitted segment. 1616 * 1617 * Note: This is more conservative than the 1618 * suggestion in draft-floyd-incr-init-win-03. 1619 */ 1620 if (rt->rt_rmx.rmx_mtu != 0) 1621 tp->snd_cwnd = 1622 TCP_INITIAL_WINDOW(tcp_init_win, 1623 rt->rt_rmx.rmx_mtu); 1624 } 1625 1626 /* 1627 * Resend unacknowledged packets. 1628 */ 1629 tp->snd_nxt = tp->snd_una; 1630 tcp_output(tp); 1631 } 1632 } 1633 #endif 1634 1635 #ifdef INET6 1636 /* 1637 * Path MTU Discovery handlers. 1638 */ 1639 void 1640 tcp6_mtudisc_callback(struct in6_addr *faddr) 1641 { 1642 struct sockaddr_in6 sin6; 1643 1644 bzero(&sin6, sizeof(sin6)); 1645 sin6.sin6_family = AF_INET6; 1646 sin6.sin6_len = sizeof(struct sockaddr_in6); 1647 sin6.sin6_addr = *faddr; 1648 (void) in6_pcbnotify(&tcbtable, (struct sockaddr *)&sin6, 0, 1649 (struct sockaddr *)&sa6_any, 0, PRC_MSGSIZE, NULL, tcp6_mtudisc); 1650 } 1651 1652 void 1653 tcp6_mtudisc(struct in6pcb *in6p, int errno) 1654 { 1655 struct tcpcb *tp = in6totcpcb(in6p); 1656 struct rtentry *rt = in6_pcbrtentry(in6p); 1657 1658 if (tp != 0) { 1659 if (rt != 0) { 1660 /* 1661 * If this was not a host route, remove and realloc. 1662 */ 1663 if ((rt->rt_flags & RTF_HOST) == 0) { 1664 in6_rtchange(in6p, errno); 1665 if ((rt = in6_pcbrtentry(in6p)) == 0) 1666 return; 1667 } 1668 1669 /* 1670 * Slow start out of the error condition. We 1671 * use the MTU because we know it's smaller 1672 * than the previously transmitted segment. 1673 * 1674 * Note: This is more conservative than the 1675 * suggestion in draft-floyd-incr-init-win-03. 1676 */ 1677 if (rt->rt_rmx.rmx_mtu != 0) 1678 tp->snd_cwnd = 1679 TCP_INITIAL_WINDOW(tcp_init_win, 1680 rt->rt_rmx.rmx_mtu); 1681 } 1682 1683 /* 1684 * Resend unacknowledged packets. 1685 */ 1686 tp->snd_nxt = tp->snd_una; 1687 tcp_output(tp); 1688 } 1689 } 1690 #endif /* INET6 */ 1691 1692 /* 1693 * Compute the MSS to advertise to the peer. Called only during 1694 * the 3-way handshake. If we are the server (peer initiated 1695 * connection), we are called with a pointer to the interface 1696 * on which the SYN packet arrived. If we are the client (we 1697 * initiated connection), we are called with a pointer to the 1698 * interface out which this connection should go. 1699 * 1700 * NOTE: Do not subtract IP option/extension header size nor IPsec 1701 * header size from MSS advertisement. MSS option must hold the maximum 1702 * segment size we can accept, so it must always be: 1703 * max(if mtu) - ip header - tcp header 1704 */ 1705 u_long 1706 tcp_mss_to_advertise(const struct ifnet *ifp, int af) 1707 { 1708 extern u_long in_maxmtu; 1709 u_long mss = 0; 1710 u_long hdrsiz; 1711 1712 /* 1713 * In order to avoid defeating path MTU discovery on the peer, 1714 * we advertise the max MTU of all attached networks as our MSS, 1715 * per RFC 1191, section 3.1. 1716 * 1717 * We provide the option to advertise just the MTU of 1718 * the interface on which we hope this connection will 1719 * be receiving. If we are responding to a SYN, we 1720 * will have a pretty good idea about this, but when 1721 * initiating a connection there is a bit more doubt. 1722 * 1723 * We also need to ensure that loopback has a large enough 1724 * MSS, as the loopback MTU is never included in in_maxmtu. 1725 */ 1726 1727 if (ifp != NULL) 1728 switch (af) { 1729 case AF_INET: 1730 mss = ifp->if_mtu; 1731 break; 1732 #ifdef INET6 1733 case AF_INET6: 1734 mss = IN6_LINKMTU(ifp); 1735 break; 1736 #endif 1737 } 1738 1739 if (tcp_mss_ifmtu == 0) 1740 switch (af) { 1741 case AF_INET: 1742 mss = max(in_maxmtu, mss); 1743 break; 1744 #ifdef INET6 1745 case AF_INET6: 1746 mss = max(in6_maxmtu, mss); 1747 break; 1748 #endif 1749 } 1750 1751 switch (af) { 1752 case AF_INET: 1753 hdrsiz = sizeof(struct ip); 1754 break; 1755 #ifdef INET6 1756 case AF_INET6: 1757 hdrsiz = sizeof(struct ip6_hdr); 1758 break; 1759 #endif 1760 default: 1761 hdrsiz = 0; 1762 break; 1763 } 1764 hdrsiz += sizeof(struct tcphdr); 1765 if (mss > hdrsiz) 1766 mss -= hdrsiz; 1767 1768 mss = max(tcp_mssdflt, mss); 1769 return (mss); 1770 } 1771 1772 /* 1773 * Set connection variables based on the peer's advertised MSS. 1774 * We are passed the TCPCB for the actual connection. If we 1775 * are the server, we are called by the compressed state engine 1776 * when the 3-way handshake is complete. If we are the client, 1777 * we are called when we receive the SYN,ACK from the server. 1778 * 1779 * NOTE: Our advertised MSS value must be initialized in the TCPCB 1780 * before this routine is called! 1781 */ 1782 void 1783 tcp_mss_from_peer(struct tcpcb *tp, int offer) 1784 { 1785 struct socket *so; 1786 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1787 struct rtentry *rt; 1788 #endif 1789 u_long bufsize; 1790 int mss; 1791 1792 #ifdef DIAGNOSTIC 1793 if (tp->t_inpcb && tp->t_in6pcb) 1794 panic("tcp_mss_from_peer: both t_inpcb and t_in6pcb are set"); 1795 #endif 1796 so = NULL; 1797 rt = NULL; 1798 #ifdef INET 1799 if (tp->t_inpcb) { 1800 so = tp->t_inpcb->inp_socket; 1801 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1802 rt = in_pcbrtentry(tp->t_inpcb); 1803 #endif 1804 } 1805 #endif 1806 #ifdef INET6 1807 if (tp->t_in6pcb) { 1808 so = tp->t_in6pcb->in6p_socket; 1809 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1810 rt = in6_pcbrtentry(tp->t_in6pcb); 1811 #endif 1812 } 1813 #endif 1814 1815 /* 1816 * As per RFC1122, use the default MSS value, unless they 1817 * sent us an offer. Do not accept offers less than 256 bytes. 1818 */ 1819 mss = tcp_mssdflt; 1820 if (offer) 1821 mss = offer; 1822 mss = max(mss, 256); /* sanity */ 1823 tp->t_peermss = mss; 1824 mss -= tcp_optlen(tp); 1825 #ifdef INET 1826 if (tp->t_inpcb) 1827 mss -= ip_optlen(tp->t_inpcb); 1828 #endif 1829 #ifdef INET6 1830 if (tp->t_in6pcb) 1831 mss -= ip6_optlen(tp->t_in6pcb); 1832 #endif 1833 1834 /* 1835 * If there's a pipesize, change the socket buffer to that size. 1836 * Make the socket buffer an integral number of MSS units. If 1837 * the MSS is larger than the socket buffer, artificially decrease 1838 * the MSS. 1839 */ 1840 #ifdef RTV_SPIPE 1841 if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0) 1842 bufsize = rt->rt_rmx.rmx_sendpipe; 1843 else 1844 #endif 1845 bufsize = so->so_snd.sb_hiwat; 1846 if (bufsize < mss) 1847 mss = bufsize; 1848 else { 1849 bufsize = roundup(bufsize, mss); 1850 if (bufsize > sb_max) 1851 bufsize = sb_max; 1852 (void) sbreserve(&so->so_snd, bufsize, so); 1853 } 1854 tp->t_segsz = mss; 1855 1856 #ifdef RTV_SSTHRESH 1857 if (rt != NULL && rt->rt_rmx.rmx_ssthresh) { 1858 /* 1859 * There's some sort of gateway or interface buffer 1860 * limit on the path. Use this to set the slow 1861 * start threshold, but set the threshold to no less 1862 * than 2 * MSS. 1863 */ 1864 tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh); 1865 } 1866 #endif 1867 } 1868 1869 /* 1870 * Processing necessary when a TCP connection is established. 1871 */ 1872 void 1873 tcp_established(struct tcpcb *tp) 1874 { 1875 struct socket *so; 1876 #ifdef RTV_RPIPE 1877 struct rtentry *rt; 1878 #endif 1879 u_long bufsize; 1880 1881 #ifdef DIAGNOSTIC 1882 if (tp->t_inpcb && tp->t_in6pcb) 1883 panic("tcp_established: both t_inpcb and t_in6pcb are set"); 1884 #endif 1885 so = NULL; 1886 rt = NULL; 1887 #ifdef INET 1888 if (tp->t_inpcb) { 1889 so = tp->t_inpcb->inp_socket; 1890 #if defined(RTV_RPIPE) 1891 rt = in_pcbrtentry(tp->t_inpcb); 1892 #endif 1893 } 1894 #endif 1895 #ifdef INET6 1896 if (tp->t_in6pcb) { 1897 so = tp->t_in6pcb->in6p_socket; 1898 #if defined(RTV_RPIPE) 1899 rt = in6_pcbrtentry(tp->t_in6pcb); 1900 #endif 1901 } 1902 #endif 1903 1904 tp->t_state = TCPS_ESTABLISHED; 1905 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle); 1906 1907 #ifdef RTV_RPIPE 1908 if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0) 1909 bufsize = rt->rt_rmx.rmx_recvpipe; 1910 else 1911 #endif 1912 bufsize = so->so_rcv.sb_hiwat; 1913 if (bufsize > tp->t_ourmss) { 1914 bufsize = roundup(bufsize, tp->t_ourmss); 1915 if (bufsize > sb_max) 1916 bufsize = sb_max; 1917 (void) sbreserve(&so->so_rcv, bufsize, so); 1918 } 1919 } 1920 1921 /* 1922 * Check if there's an initial rtt or rttvar. Convert from the 1923 * route-table units to scaled multiples of the slow timeout timer. 1924 * Called only during the 3-way handshake. 1925 */ 1926 void 1927 tcp_rmx_rtt(struct tcpcb *tp) 1928 { 1929 #ifdef RTV_RTT 1930 struct rtentry *rt = NULL; 1931 int rtt; 1932 1933 #ifdef DIAGNOSTIC 1934 if (tp->t_inpcb && tp->t_in6pcb) 1935 panic("tcp_rmx_rtt: both t_inpcb and t_in6pcb are set"); 1936 #endif 1937 #ifdef INET 1938 if (tp->t_inpcb) 1939 rt = in_pcbrtentry(tp->t_inpcb); 1940 #endif 1941 #ifdef INET6 1942 if (tp->t_in6pcb) 1943 rt = in6_pcbrtentry(tp->t_in6pcb); 1944 #endif 1945 if (rt == NULL) 1946 return; 1947 1948 if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) { 1949 /* 1950 * XXX The lock bit for MTU indicates that the value 1951 * is also a minimum value; this is subject to time. 1952 */ 1953 if (rt->rt_rmx.rmx_locks & RTV_RTT) 1954 TCPT_RANGESET(tp->t_rttmin, 1955 rtt / (RTM_RTTUNIT / PR_SLOWHZ), 1956 TCPTV_MIN, TCPTV_REXMTMAX); 1957 tp->t_srtt = rtt / 1958 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1959 if (rt->rt_rmx.rmx_rttvar) { 1960 tp->t_rttvar = rt->rt_rmx.rmx_rttvar / 1961 ((RTM_RTTUNIT / PR_SLOWHZ) >> 1962 (TCP_RTTVAR_SHIFT + 2)); 1963 } else { 1964 /* Default variation is +- 1 rtt */ 1965 tp->t_rttvar = 1966 tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT); 1967 } 1968 TCPT_RANGESET(tp->t_rxtcur, 1969 ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2), 1970 tp->t_rttmin, TCPTV_REXMTMAX); 1971 } 1972 #endif 1973 } 1974 1975 tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */ 1976 #if NRND > 0 1977 u_int8_t tcp_iss_secret[16]; /* 128 bits; should be plenty */ 1978 #endif 1979 1980 /* 1981 * Get a new sequence value given a tcp control block 1982 */ 1983 tcp_seq 1984 tcp_new_iss(struct tcpcb *tp, tcp_seq addin) 1985 { 1986 1987 #ifdef INET 1988 if (tp->t_inpcb != NULL) { 1989 return (tcp_new_iss1(&tp->t_inpcb->inp_laddr, 1990 &tp->t_inpcb->inp_faddr, tp->t_inpcb->inp_lport, 1991 tp->t_inpcb->inp_fport, sizeof(tp->t_inpcb->inp_laddr), 1992 addin)); 1993 } 1994 #endif 1995 #ifdef INET6 1996 if (tp->t_in6pcb != NULL) { 1997 return (tcp_new_iss1(&tp->t_in6pcb->in6p_laddr, 1998 &tp->t_in6pcb->in6p_faddr, tp->t_in6pcb->in6p_lport, 1999 tp->t_in6pcb->in6p_fport, sizeof(tp->t_in6pcb->in6p_laddr), 2000 addin)); 2001 } 2002 #endif 2003 /* Not possible. */ 2004 panic("tcp_new_iss"); 2005 } 2006 2007 /* 2008 * This routine actually generates a new TCP initial sequence number. 2009 */ 2010 tcp_seq 2011 tcp_new_iss1(void *laddr, void *faddr, u_int16_t lport, u_int16_t fport, 2012 size_t addrsz, tcp_seq addin) 2013 { 2014 tcp_seq tcp_iss; 2015 2016 #if NRND > 0 2017 static int beenhere; 2018 2019 /* 2020 * If we haven't been here before, initialize our cryptographic 2021 * hash secret. 2022 */ 2023 if (beenhere == 0) { 2024 rnd_extract_data(tcp_iss_secret, sizeof(tcp_iss_secret), 2025 RND_EXTRACT_ANY); 2026 beenhere = 1; 2027 } 2028 2029 if (tcp_do_rfc1948) { 2030 MD5_CTX ctx; 2031 u_int8_t hash[16]; /* XXX MD5 knowledge */ 2032 2033 /* 2034 * Compute the base value of the ISS. It is a hash 2035 * of (saddr, sport, daddr, dport, secret). 2036 */ 2037 MD5Init(&ctx); 2038 2039 MD5Update(&ctx, (u_char *) laddr, addrsz); 2040 MD5Update(&ctx, (u_char *) &lport, sizeof(lport)); 2041 2042 MD5Update(&ctx, (u_char *) faddr, addrsz); 2043 MD5Update(&ctx, (u_char *) &fport, sizeof(fport)); 2044 2045 MD5Update(&ctx, tcp_iss_secret, sizeof(tcp_iss_secret)); 2046 2047 MD5Final(hash, &ctx); 2048 2049 memcpy(&tcp_iss, hash, sizeof(tcp_iss)); 2050 2051 /* 2052 * Now increment our "timer", and add it in to 2053 * the computed value. 2054 * 2055 * XXX Use `addin'? 2056 * XXX TCP_ISSINCR too large to use? 2057 */ 2058 tcp_iss_seq += TCP_ISSINCR; 2059 #ifdef TCPISS_DEBUG 2060 printf("ISS hash 0x%08x, ", tcp_iss); 2061 #endif 2062 tcp_iss += tcp_iss_seq + addin; 2063 #ifdef TCPISS_DEBUG 2064 printf("new ISS 0x%08x\n", tcp_iss); 2065 #endif 2066 } else 2067 #endif /* NRND > 0 */ 2068 { 2069 /* 2070 * Randomize. 2071 */ 2072 #if NRND > 0 2073 rnd_extract_data(&tcp_iss, sizeof(tcp_iss), RND_EXTRACT_ANY); 2074 #else 2075 tcp_iss = arc4random(); 2076 #endif 2077 2078 /* 2079 * If we were asked to add some amount to a known value, 2080 * we will take a random value obtained above, mask off 2081 * the upper bits, and add in the known value. We also 2082 * add in a constant to ensure that we are at least a 2083 * certain distance from the original value. 2084 * 2085 * This is used when an old connection is in timed wait 2086 * and we have a new one coming in, for instance. 2087 */ 2088 if (addin != 0) { 2089 #ifdef TCPISS_DEBUG 2090 printf("Random %08x, ", tcp_iss); 2091 #endif 2092 tcp_iss &= TCP_ISS_RANDOM_MASK; 2093 tcp_iss += addin + TCP_ISSINCR; 2094 #ifdef TCPISS_DEBUG 2095 printf("Old ISS %08x, ISS %08x\n", addin, tcp_iss); 2096 #endif 2097 } else { 2098 tcp_iss &= TCP_ISS_RANDOM_MASK; 2099 tcp_iss += tcp_iss_seq; 2100 tcp_iss_seq += TCP_ISSINCR; 2101 #ifdef TCPISS_DEBUG 2102 printf("ISS %08x\n", tcp_iss); 2103 #endif 2104 } 2105 } 2106 2107 if (tcp_compat_42) { 2108 /* 2109 * Limit it to the positive range for really old TCP 2110 * implementations. 2111 * Just AND off the top bit instead of checking if 2112 * is set first - saves a branch 50% of the time. 2113 */ 2114 tcp_iss &= 0x7fffffff; /* XXX */ 2115 } 2116 2117 return (tcp_iss); 2118 } 2119 2120 #if defined(IPSEC) || defined(FAST_IPSEC) 2121 /* compute ESP/AH header size for TCP, including outer IP header. */ 2122 size_t 2123 ipsec4_hdrsiz_tcp(struct tcpcb *tp) 2124 { 2125 struct inpcb *inp; 2126 size_t hdrsiz; 2127 2128 /* XXX mapped addr case (tp->t_in6pcb) */ 2129 if (!tp || !tp->t_template || !(inp = tp->t_inpcb)) 2130 return 0; 2131 switch (tp->t_family) { 2132 case AF_INET: 2133 /* XXX: should use currect direction. */ 2134 hdrsiz = ipsec4_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, inp); 2135 break; 2136 default: 2137 hdrsiz = 0; 2138 break; 2139 } 2140 2141 return hdrsiz; 2142 } 2143 2144 #ifdef INET6 2145 size_t 2146 ipsec6_hdrsiz_tcp(struct tcpcb *tp) 2147 { 2148 struct in6pcb *in6p; 2149 size_t hdrsiz; 2150 2151 if (!tp || !tp->t_template || !(in6p = tp->t_in6pcb)) 2152 return 0; 2153 switch (tp->t_family) { 2154 case AF_INET6: 2155 /* XXX: should use currect direction. */ 2156 hdrsiz = ipsec6_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, in6p); 2157 break; 2158 case AF_INET: 2159 /* mapped address case - tricky */ 2160 default: 2161 hdrsiz = 0; 2162 break; 2163 } 2164 2165 return hdrsiz; 2166 } 2167 #endif 2168 #endif /*IPSEC*/ 2169 2170 /* 2171 * Determine the length of the TCP options for this connection. 2172 * 2173 * XXX: What do we do for SACK, when we add that? Just reserve 2174 * all of the space? Otherwise we can't exactly be incrementing 2175 * cwnd by an amount that varies depending on the amount we last 2176 * had to SACK! 2177 */ 2178 2179 u_int 2180 tcp_optlen(struct tcpcb *tp) 2181 { 2182 u_int optlen; 2183 2184 optlen = 0; 2185 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 2186 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 2187 optlen += TCPOLEN_TSTAMP_APPA; 2188 2189 #ifdef TCP_SIGNATURE 2190 #if defined(INET6) && defined(FAST_IPSEC) 2191 if (tp->t_family == AF_INET) 2192 #endif 2193 if (tp->t_flags & TF_SIGNATURE) 2194 optlen += TCPOLEN_SIGNATURE + 2; 2195 #endif /* TCP_SIGNATURE */ 2196 2197 return optlen; 2198 } 2199
Indexes created Tue Sep 23 07:09:52 GMT 2025