tcp_subr.c revision 1.182
1 /* $NetBSD: tcp_subr.c,v 1.182 2005/02/26 22:45:12 perry 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 1.182 2005/02/26 22:45:12 perry 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 .t_partialacks = -1, 912 }; 913 914 /* 915 * Updates the TCPCB template whenever a parameter that would affect 916 * the template is changed. 917 */ 918 void 919 tcp_tcpcb_template(void) 920 { 921 struct tcpcb *tp = &tcpcb_template; 922 int flags; 923 924 tp->t_peermss = tcp_mssdflt; 925 tp->t_ourmss = tcp_mssdflt; 926 tp->t_segsz = tcp_mssdflt; 927 928 flags = 0; 929 if (tcp_do_rfc1323 && tcp_do_win_scale) 930 flags |= TF_REQ_SCALE; 931 if (tcp_do_rfc1323 && tcp_do_timestamps) 932 flags |= TF_REQ_TSTMP; 933 if (tcp_do_sack == 2) 934 flags |= TF_WILL_SACK; 935 else if (tcp_do_sack == 1) 936 flags |= TF_WILL_SACK|TF_IGNR_RXSACK; 937 flags |= TF_CANT_TXSACK; 938 tp->t_flags = flags; 939 940 /* 941 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 942 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 943 * reasonable initial retransmit time. 944 */ 945 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1); 946 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 947 TCPTV_MIN, TCPTV_REXMTMAX); 948 } 949 950 /* 951 * Create a new TCP control block, making an 952 * empty reassembly queue and hooking it to the argument 953 * protocol control block. 954 */ 955 /* family selects inpcb, or in6pcb */ 956 struct tcpcb * 957 tcp_newtcpcb(int family, void *aux) 958 { 959 struct tcpcb *tp; 960 int i; 961 962 /* XXX Consider using a pool_cache for speed. */ 963 tp = pool_get(&tcpcb_pool, PR_NOWAIT); 964 if (tp == NULL) 965 return (NULL); 966 memcpy(tp, &tcpcb_template, sizeof(*tp)); 967 TAILQ_INIT(&tp->segq); 968 TAILQ_INIT(&tp->timeq); 969 tp->t_family = family; /* may be overridden later on */ 970 LIST_INIT(&tp->t_sc); /* XXX can template this */ 971 972 /* Don't sweat this loop; hopefully the compiler will unroll it. */ 973 for (i = 0; i < TCPT_NTIMERS; i++) 974 TCP_TIMER_INIT(tp, i); 975 976 switch (family) { 977 case AF_INET: 978 { 979 struct inpcb *inp = (struct inpcb *)aux; 980 981 inp->inp_ip.ip_ttl = ip_defttl; 982 inp->inp_ppcb = (caddr_t)tp; 983 984 tp->t_inpcb = inp; 985 tp->t_mtudisc = ip_mtudisc; 986 break; 987 } 988 #ifdef INET6 989 case AF_INET6: 990 { 991 struct in6pcb *in6p = (struct in6pcb *)aux; 992 993 in6p->in6p_ip6.ip6_hlim = in6_selecthlim(in6p, 994 in6p->in6p_route.ro_rt ? in6p->in6p_route.ro_rt->rt_ifp 995 : NULL); 996 in6p->in6p_ppcb = (caddr_t)tp; 997 998 tp->t_in6pcb = in6p; 999 /* for IPv6, always try to run path MTU discovery */ 1000 tp->t_mtudisc = 1; 1001 break; 1002 } 1003 #endif /* INET6 */ 1004 default: 1005 pool_put(&tcpcb_pool, tp); 1006 return (NULL); 1007 } 1008 1009 /* 1010 * Initialize our timebase. When we send timestamps, we take 1011 * the delta from tcp_now -- this means each connection always 1012 * gets a timebase of 0, which makes it, among other things, 1013 * more difficult to determine how long a system has been up, 1014 * and thus how many TCP sequence increments have occurred. 1015 */ 1016 tp->ts_timebase = tcp_now; 1017 1018 return (tp); 1019 } 1020 1021 /* 1022 * Drop a TCP connection, reporting 1023 * the specified error. If connection is synchronized, 1024 * then send a RST to peer. 1025 */ 1026 struct tcpcb * 1027 tcp_drop(struct tcpcb *tp, int errno) 1028 { 1029 struct socket *so = NULL; 1030 1031 #ifdef DIAGNOSTIC 1032 if (tp->t_inpcb && tp->t_in6pcb) 1033 panic("tcp_drop: both t_inpcb and t_in6pcb are set"); 1034 #endif 1035 #ifdef INET 1036 if (tp->t_inpcb) 1037 so = tp->t_inpcb->inp_socket; 1038 #endif 1039 #ifdef INET6 1040 if (tp->t_in6pcb) 1041 so = tp->t_in6pcb->in6p_socket; 1042 #endif 1043 if (!so) 1044 return NULL; 1045 1046 if (TCPS_HAVERCVDSYN(tp->t_state)) { 1047 tp->t_state = TCPS_CLOSED; 1048 (void) tcp_output(tp); 1049 tcpstat.tcps_drops++; 1050 } else 1051 tcpstat.tcps_conndrops++; 1052 if (errno == ETIMEDOUT && tp->t_softerror) 1053 errno = tp->t_softerror; 1054 so->so_error = errno; 1055 return (tcp_close(tp)); 1056 } 1057 1058 /* 1059 * Return whether this tcpcb is marked as dead, indicating 1060 * to the calling timer function that no further action should 1061 * be taken, as we are about to release this tcpcb. The release 1062 * of the storage will be done if this is the last timer running. 1063 * 1064 * This should be called from the callout handler function after 1065 * callout_ack() is done, so that the number of invoking timer 1066 * functions is 0. 1067 */ 1068 int 1069 tcp_isdead(struct tcpcb *tp) 1070 { 1071 int dead = (tp->t_flags & TF_DEAD); 1072 1073 if (__predict_false(dead)) { 1074 if (tcp_timers_invoking(tp) > 0) 1075 /* not quite there yet -- count separately? */ 1076 return dead; 1077 tcpstat.tcps_delayed_free++; 1078 pool_put(&tcpcb_pool, tp); 1079 } 1080 return dead; 1081 } 1082 1083 /* 1084 * Close a TCP control block: 1085 * discard all space held by the tcp 1086 * discard internet protocol block 1087 * wake up any sleepers 1088 */ 1089 struct tcpcb * 1090 tcp_close(struct tcpcb *tp) 1091 { 1092 struct inpcb *inp; 1093 #ifdef INET6 1094 struct in6pcb *in6p; 1095 #endif 1096 struct socket *so; 1097 #ifdef RTV_RTT 1098 struct rtentry *rt; 1099 #endif 1100 struct route *ro; 1101 1102 inp = tp->t_inpcb; 1103 #ifdef INET6 1104 in6p = tp->t_in6pcb; 1105 #endif 1106 so = NULL; 1107 ro = NULL; 1108 if (inp) { 1109 so = inp->inp_socket; 1110 ro = &inp->inp_route; 1111 } 1112 #ifdef INET6 1113 else if (in6p) { 1114 so = in6p->in6p_socket; 1115 ro = (struct route *)&in6p->in6p_route; 1116 } 1117 #endif 1118 1119 #ifdef RTV_RTT 1120 /* 1121 * If we sent enough data to get some meaningful characteristics, 1122 * save them in the routing entry. 'Enough' is arbitrarily 1123 * defined as the sendpipesize (default 4K) * 16. This would 1124 * give us 16 rtt samples assuming we only get one sample per 1125 * window (the usual case on a long haul net). 16 samples is 1126 * enough for the srtt filter to converge to within 5% of the correct 1127 * value; fewer samples and we could save a very bogus rtt. 1128 * 1129 * Don't update the default route's characteristics and don't 1130 * update anything that the user "locked". 1131 */ 1132 if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) && 1133 ro && (rt = ro->ro_rt) && 1134 !in_nullhost(satosin(rt_key(rt))->sin_addr)) { 1135 u_long i = 0; 1136 1137 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 1138 i = tp->t_srtt * 1139 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1140 if (rt->rt_rmx.rmx_rtt && i) 1141 /* 1142 * filter this update to half the old & half 1143 * the new values, converting scale. 1144 * See route.h and tcp_var.h for a 1145 * description of the scaling constants. 1146 */ 1147 rt->rt_rmx.rmx_rtt = 1148 (rt->rt_rmx.rmx_rtt + i) / 2; 1149 else 1150 rt->rt_rmx.rmx_rtt = i; 1151 } 1152 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 1153 i = tp->t_rttvar * 1154 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2)); 1155 if (rt->rt_rmx.rmx_rttvar && i) 1156 rt->rt_rmx.rmx_rttvar = 1157 (rt->rt_rmx.rmx_rttvar + i) / 2; 1158 else 1159 rt->rt_rmx.rmx_rttvar = i; 1160 } 1161 /* 1162 * update the pipelimit (ssthresh) if it has been updated 1163 * already or if a pipesize was specified & the threshhold 1164 * got below half the pipesize. I.e., wait for bad news 1165 * before we start updating, then update on both good 1166 * and bad news. 1167 */ 1168 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 1169 (i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) || 1170 i < (rt->rt_rmx.rmx_sendpipe / 2)) { 1171 /* 1172 * convert the limit from user data bytes to 1173 * packets then to packet data bytes. 1174 */ 1175 i = (i + tp->t_segsz / 2) / tp->t_segsz; 1176 if (i < 2) 1177 i = 2; 1178 i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr)); 1179 if (rt->rt_rmx.rmx_ssthresh) 1180 rt->rt_rmx.rmx_ssthresh = 1181 (rt->rt_rmx.rmx_ssthresh + i) / 2; 1182 else 1183 rt->rt_rmx.rmx_ssthresh = i; 1184 } 1185 } 1186 #endif /* RTV_RTT */ 1187 /* free the reassembly queue, if any */ 1188 TCP_REASS_LOCK(tp); 1189 (void) tcp_freeq(tp); 1190 TCP_REASS_UNLOCK(tp); 1191 1192 tcp_canceltimers(tp); 1193 TCP_CLEAR_DELACK(tp); 1194 syn_cache_cleanup(tp); 1195 1196 if (tp->t_template) { 1197 m_free(tp->t_template); 1198 tp->t_template = NULL; 1199 } 1200 if (tcp_timers_invoking(tp)) 1201 tp->t_flags |= TF_DEAD; 1202 else 1203 pool_put(&tcpcb_pool, tp); 1204 1205 if (inp) { 1206 inp->inp_ppcb = 0; 1207 soisdisconnected(so); 1208 in_pcbdetach(inp); 1209 } 1210 #ifdef INET6 1211 else if (in6p) { 1212 in6p->in6p_ppcb = 0; 1213 soisdisconnected(so); 1214 in6_pcbdetach(in6p); 1215 } 1216 #endif 1217 tcpstat.tcps_closed++; 1218 return ((struct tcpcb *)0); 1219 } 1220 1221 int 1222 tcp_freeq(tp) 1223 struct tcpcb *tp; 1224 { 1225 struct ipqent *qe; 1226 int rv = 0; 1227 #ifdef TCPREASS_DEBUG 1228 int i = 0; 1229 #endif 1230 1231 TCP_REASS_LOCK_CHECK(tp); 1232 1233 while ((qe = TAILQ_FIRST(&tp->segq)) != NULL) { 1234 #ifdef TCPREASS_DEBUG 1235 printf("tcp_freeq[%p,%d]: %u:%u(%u) 0x%02x\n", 1236 tp, i++, qe->ipqe_seq, qe->ipqe_seq + qe->ipqe_len, 1237 qe->ipqe_len, qe->ipqe_flags & (TH_SYN|TH_FIN|TH_RST)); 1238 #endif 1239 TAILQ_REMOVE(&tp->segq, qe, ipqe_q); 1240 TAILQ_REMOVE(&tp->timeq, qe, ipqe_timeq); 1241 m_freem(qe->ipqe_m); 1242 pool_put(&tcpipqent_pool, qe); 1243 rv = 1; 1244 } 1245 return (rv); 1246 } 1247 1248 /* 1249 * Protocol drain routine. Called when memory is in short supply. 1250 */ 1251 void 1252 tcp_drain(void) 1253 { 1254 struct inpcb_hdr *inph; 1255 struct tcpcb *tp; 1256 1257 /* 1258 * Free the sequence queue of all TCP connections. 1259 */ 1260 CIRCLEQ_FOREACH(inph, &tcbtable.inpt_queue, inph_queue) { 1261 switch (inph->inph_af) { 1262 case AF_INET: 1263 tp = intotcpcb((struct inpcb *)inph); 1264 break; 1265 #ifdef INET6 1266 case AF_INET6: 1267 tp = in6totcpcb((struct in6pcb *)inph); 1268 break; 1269 #endif 1270 default: 1271 tp = NULL; 1272 break; 1273 } 1274 if (tp != NULL) { 1275 /* 1276 * We may be called from a device's interrupt 1277 * context. If the tcpcb is already busy, 1278 * just bail out now. 1279 */ 1280 if (tcp_reass_lock_try(tp) == 0) 1281 continue; 1282 if (tcp_freeq(tp)) 1283 tcpstat.tcps_connsdrained++; 1284 TCP_REASS_UNLOCK(tp); 1285 } 1286 } 1287 } 1288 1289 /* 1290 * Notify a tcp user of an asynchronous error; 1291 * store error as soft error, but wake up user 1292 * (for now, won't do anything until can select for soft error). 1293 */ 1294 void 1295 tcp_notify(struct inpcb *inp, int error) 1296 { 1297 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 1298 struct socket *so = inp->inp_socket; 1299 1300 /* 1301 * Ignore some errors if we are hooked up. 1302 * If connection hasn't completed, has retransmitted several times, 1303 * and receives a second error, give up now. This is better 1304 * than waiting a long time to establish a connection that 1305 * can never complete. 1306 */ 1307 if (tp->t_state == TCPS_ESTABLISHED && 1308 (error == EHOSTUNREACH || error == ENETUNREACH || 1309 error == EHOSTDOWN)) { 1310 return; 1311 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1312 tp->t_rxtshift > 3 && tp->t_softerror) 1313 so->so_error = error; 1314 else 1315 tp->t_softerror = error; 1316 wakeup((caddr_t) &so->so_timeo); 1317 sorwakeup(so); 1318 sowwakeup(so); 1319 } 1320 1321 #ifdef INET6 1322 void 1323 tcp6_notify(struct in6pcb *in6p, int error) 1324 { 1325 struct tcpcb *tp = (struct tcpcb *)in6p->in6p_ppcb; 1326 struct socket *so = in6p->in6p_socket; 1327 1328 /* 1329 * Ignore some errors if we are hooked up. 1330 * If connection hasn't completed, has retransmitted several times, 1331 * and receives a second error, give up now. This is better 1332 * than waiting a long time to establish a connection that 1333 * can never complete. 1334 */ 1335 if (tp->t_state == TCPS_ESTABLISHED && 1336 (error == EHOSTUNREACH || error == ENETUNREACH || 1337 error == EHOSTDOWN)) { 1338 return; 1339 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1340 tp->t_rxtshift > 3 && tp->t_softerror) 1341 so->so_error = error; 1342 else 1343 tp->t_softerror = error; 1344 wakeup((caddr_t) &so->so_timeo); 1345 sorwakeup(so); 1346 sowwakeup(so); 1347 } 1348 #endif 1349 1350 #ifdef INET6 1351 void 1352 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1353 { 1354 struct tcphdr th; 1355 void (*notify)(struct in6pcb *, int) = tcp6_notify; 1356 int nmatch; 1357 struct ip6_hdr *ip6; 1358 const struct sockaddr_in6 *sa6_src = NULL; 1359 struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)sa; 1360 struct mbuf *m; 1361 int off; 1362 1363 if (sa->sa_family != AF_INET6 || 1364 sa->sa_len != sizeof(struct sockaddr_in6)) 1365 return; 1366 if ((unsigned)cmd >= PRC_NCMDS) 1367 return; 1368 else if (cmd == PRC_QUENCH) { 1369 /* XXX there's no PRC_QUENCH in IPv6 */ 1370 notify = tcp6_quench; 1371 } else if (PRC_IS_REDIRECT(cmd)) 1372 notify = in6_rtchange, d = NULL; 1373 else if (cmd == PRC_MSGSIZE) 1374 ; /* special code is present, see below */ 1375 else if (cmd == PRC_HOSTDEAD) 1376 d = NULL; 1377 else if (inet6ctlerrmap[cmd] == 0) 1378 return; 1379 1380 /* if the parameter is from icmp6, decode it. */ 1381 if (d != NULL) { 1382 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 1383 m = ip6cp->ip6c_m; 1384 ip6 = ip6cp->ip6c_ip6; 1385 off = ip6cp->ip6c_off; 1386 sa6_src = ip6cp->ip6c_src; 1387 } else { 1388 m = NULL; 1389 ip6 = NULL; 1390 sa6_src = &sa6_any; 1391 off = 0; 1392 } 1393 1394 if (ip6) { 1395 /* 1396 * XXX: We assume that when ip6 is non NULL, 1397 * M and OFF are valid. 1398 */ 1399 1400 /* check if we can safely examine src and dst ports */ 1401 if (m->m_pkthdr.len < off + sizeof(th)) { 1402 if (cmd == PRC_MSGSIZE) 1403 icmp6_mtudisc_update((struct ip6ctlparam *)d, 0); 1404 return; 1405 } 1406 1407 bzero(&th, sizeof(th)); 1408 m_copydata(m, off, sizeof(th), (caddr_t)&th); 1409 1410 if (cmd == PRC_MSGSIZE) { 1411 int valid = 0; 1412 1413 /* 1414 * Check to see if we have a valid TCP connection 1415 * corresponding to the address in the ICMPv6 message 1416 * payload. 1417 */ 1418 if (in6_pcblookup_connect(&tcbtable, &sa6->sin6_addr, 1419 th.th_dport, (struct in6_addr *)&sa6_src->sin6_addr, 1420 th.th_sport, 0)) 1421 valid++; 1422 1423 /* 1424 * Depending on the value of "valid" and routing table 1425 * size (mtudisc_{hi,lo}wat), we will: 1426 * - recalcurate the new MTU and create the 1427 * corresponding routing entry, or 1428 * - ignore the MTU change notification. 1429 */ 1430 icmp6_mtudisc_update((struct ip6ctlparam *)d, valid); 1431 1432 /* 1433 * no need to call in6_pcbnotify, it should have been 1434 * called via callback if necessary 1435 */ 1436 return; 1437 } 1438 1439 nmatch = in6_pcbnotify(&tcbtable, sa, th.th_dport, 1440 (struct sockaddr *)sa6_src, th.th_sport, cmd, NULL, notify); 1441 if (nmatch == 0 && syn_cache_count && 1442 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 1443 inet6ctlerrmap[cmd] == ENETUNREACH || 1444 inet6ctlerrmap[cmd] == EHOSTDOWN)) 1445 syn_cache_unreach((struct sockaddr *)sa6_src, 1446 sa, &th); 1447 } else { 1448 (void) in6_pcbnotify(&tcbtable, sa, 0, 1449 (struct sockaddr *)sa6_src, 0, cmd, NULL, notify); 1450 } 1451 } 1452 #endif 1453 1454 #ifdef INET 1455 /* assumes that ip header and tcp header are contiguous on mbuf */ 1456 void * 1457 tcp_ctlinput(int cmd, struct sockaddr *sa, void *v) 1458 { 1459 struct ip *ip = v; 1460 struct tcphdr *th; 1461 struct icmp *icp; 1462 extern const int inetctlerrmap[]; 1463 void (*notify)(struct inpcb *, int) = tcp_notify; 1464 int errno; 1465 int nmatch; 1466 #ifdef INET6 1467 struct in6_addr src6, dst6; 1468 #endif 1469 1470 if (sa->sa_family != AF_INET || 1471 sa->sa_len != sizeof(struct sockaddr_in)) 1472 return NULL; 1473 if ((unsigned)cmd >= PRC_NCMDS) 1474 return NULL; 1475 errno = inetctlerrmap[cmd]; 1476 if (cmd == PRC_QUENCH) 1477 notify = tcp_quench; 1478 else if (PRC_IS_REDIRECT(cmd)) 1479 notify = in_rtchange, ip = 0; 1480 else if (cmd == PRC_MSGSIZE && ip && ip->ip_v == 4) { 1481 /* 1482 * Check to see if we have a valid TCP connection 1483 * corresponding to the address in the ICMP message 1484 * payload. 1485 * 1486 * Boundary check is made in icmp_input(), with ICMP_ADVLENMIN. 1487 */ 1488 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1489 #ifdef INET6 1490 memset(&src6, 0, sizeof(src6)); 1491 memset(&dst6, 0, sizeof(dst6)); 1492 src6.s6_addr16[5] = dst6.s6_addr16[5] = 0xffff; 1493 memcpy(&src6.s6_addr32[3], &ip->ip_src, sizeof(struct in_addr)); 1494 memcpy(&dst6.s6_addr32[3], &ip->ip_dst, sizeof(struct in_addr)); 1495 #endif 1496 if (in_pcblookup_connect(&tcbtable, ip->ip_dst, th->th_dport, 1497 ip->ip_src, th->th_sport) != NULL) 1498 ; 1499 #ifdef INET6 1500 else if (in6_pcblookup_connect(&tcbtable, &dst6, 1501 th->th_dport, &src6, th->th_sport, 0) != NULL) 1502 ; 1503 #endif 1504 else 1505 return NULL; 1506 1507 /* 1508 * Now that we've validated that we are actually communicating 1509 * with the host indicated in the ICMP message, locate the 1510 * ICMP header, recalculate the new MTU, and create the 1511 * corresponding routing entry. 1512 */ 1513 icp = (struct icmp *)((caddr_t)ip - 1514 offsetof(struct icmp, icmp_ip)); 1515 icmp_mtudisc(icp, ip->ip_dst); 1516 1517 return NULL; 1518 } else if (cmd == PRC_HOSTDEAD) 1519 ip = 0; 1520 else if (errno == 0) 1521 return NULL; 1522 if (ip && ip->ip_v == 4 && sa->sa_family == AF_INET) { 1523 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1524 nmatch = in_pcbnotify(&tcbtable, satosin(sa)->sin_addr, 1525 th->th_dport, ip->ip_src, th->th_sport, errno, notify); 1526 if (nmatch == 0 && syn_cache_count && 1527 (inetctlerrmap[cmd] == EHOSTUNREACH || 1528 inetctlerrmap[cmd] == ENETUNREACH || 1529 inetctlerrmap[cmd] == EHOSTDOWN)) { 1530 struct sockaddr_in sin; 1531 bzero(&sin, sizeof(sin)); 1532 sin.sin_len = sizeof(sin); 1533 sin.sin_family = AF_INET; 1534 sin.sin_port = th->th_sport; 1535 sin.sin_addr = ip->ip_src; 1536 syn_cache_unreach((struct sockaddr *)&sin, sa, th); 1537 } 1538 1539 /* XXX mapped address case */ 1540 } else 1541 in_pcbnotifyall(&tcbtable, satosin(sa)->sin_addr, errno, 1542 notify); 1543 return NULL; 1544 } 1545 1546 /* 1547 * When a source quence is received, we are being notifed of congestion. 1548 * Close the congestion window down to the Loss Window (one segment). 1549 * We will gradually open it again as we proceed. 1550 */ 1551 void 1552 tcp_quench(struct inpcb *inp, int errno) 1553 { 1554 struct tcpcb *tp = intotcpcb(inp); 1555 1556 if (tp) 1557 tp->snd_cwnd = tp->t_segsz; 1558 } 1559 #endif 1560 1561 #ifdef INET6 1562 void 1563 tcp6_quench(struct in6pcb *in6p, int errno) 1564 { 1565 struct tcpcb *tp = in6totcpcb(in6p); 1566 1567 if (tp) 1568 tp->snd_cwnd = tp->t_segsz; 1569 } 1570 #endif 1571 1572 #ifdef INET 1573 /* 1574 * Path MTU Discovery handlers. 1575 */ 1576 void 1577 tcp_mtudisc_callback(struct in_addr faddr) 1578 { 1579 #ifdef INET6 1580 struct in6_addr in6; 1581 #endif 1582 1583 in_pcbnotifyall(&tcbtable, faddr, EMSGSIZE, tcp_mtudisc); 1584 #ifdef INET6 1585 memset(&in6, 0, sizeof(in6)); 1586 in6.s6_addr16[5] = 0xffff; 1587 memcpy(&in6.s6_addr32[3], &faddr, sizeof(struct in_addr)); 1588 tcp6_mtudisc_callback(&in6); 1589 #endif 1590 } 1591 1592 /* 1593 * On receipt of path MTU corrections, flush old route and replace it 1594 * with the new one. Retransmit all unacknowledged packets, to ensure 1595 * that all packets will be received. 1596 */ 1597 void 1598 tcp_mtudisc(struct inpcb *inp, int errno) 1599 { 1600 struct tcpcb *tp = intotcpcb(inp); 1601 struct rtentry *rt = in_pcbrtentry(inp); 1602 1603 if (tp != 0) { 1604 if (rt != 0) { 1605 /* 1606 * If this was not a host route, remove and realloc. 1607 */ 1608 if ((rt->rt_flags & RTF_HOST) == 0) { 1609 in_rtchange(inp, errno); 1610 if ((rt = in_pcbrtentry(inp)) == 0) 1611 return; 1612 } 1613 1614 /* 1615 * Slow start out of the error condition. We 1616 * use the MTU because we know it's smaller 1617 * than the previously transmitted segment. 1618 * 1619 * Note: This is more conservative than the 1620 * suggestion in draft-floyd-incr-init-win-03. 1621 */ 1622 if (rt->rt_rmx.rmx_mtu != 0) 1623 tp->snd_cwnd = 1624 TCP_INITIAL_WINDOW(tcp_init_win, 1625 rt->rt_rmx.rmx_mtu); 1626 } 1627 1628 /* 1629 * Resend unacknowledged packets. 1630 */ 1631 tp->snd_nxt = tp->snd_una; 1632 tcp_output(tp); 1633 } 1634 } 1635 #endif 1636 1637 #ifdef INET6 1638 /* 1639 * Path MTU Discovery handlers. 1640 */ 1641 void 1642 tcp6_mtudisc_callback(struct in6_addr *faddr) 1643 { 1644 struct sockaddr_in6 sin6; 1645 1646 bzero(&sin6, sizeof(sin6)); 1647 sin6.sin6_family = AF_INET6; 1648 sin6.sin6_len = sizeof(struct sockaddr_in6); 1649 sin6.sin6_addr = *faddr; 1650 (void) in6_pcbnotify(&tcbtable, (struct sockaddr *)&sin6, 0, 1651 (struct sockaddr *)&sa6_any, 0, PRC_MSGSIZE, NULL, tcp6_mtudisc); 1652 } 1653 1654 void 1655 tcp6_mtudisc(struct in6pcb *in6p, int errno) 1656 { 1657 struct tcpcb *tp = in6totcpcb(in6p); 1658 struct rtentry *rt = in6_pcbrtentry(in6p); 1659 1660 if (tp != 0) { 1661 if (rt != 0) { 1662 /* 1663 * If this was not a host route, remove and realloc. 1664 */ 1665 if ((rt->rt_flags & RTF_HOST) == 0) { 1666 in6_rtchange(in6p, errno); 1667 if ((rt = in6_pcbrtentry(in6p)) == 0) 1668 return; 1669 } 1670 1671 /* 1672 * Slow start out of the error condition. We 1673 * use the MTU because we know it's smaller 1674 * than the previously transmitted segment. 1675 * 1676 * Note: This is more conservative than the 1677 * suggestion in draft-floyd-incr-init-win-03. 1678 */ 1679 if (rt->rt_rmx.rmx_mtu != 0) 1680 tp->snd_cwnd = 1681 TCP_INITIAL_WINDOW(tcp_init_win, 1682 rt->rt_rmx.rmx_mtu); 1683 } 1684 1685 /* 1686 * Resend unacknowledged packets. 1687 */ 1688 tp->snd_nxt = tp->snd_una; 1689 tcp_output(tp); 1690 } 1691 } 1692 #endif /* INET6 */ 1693 1694 /* 1695 * Compute the MSS to advertise to the peer. Called only during 1696 * the 3-way handshake. If we are the server (peer initiated 1697 * connection), we are called with a pointer to the interface 1698 * on which the SYN packet arrived. If we are the client (we 1699 * initiated connection), we are called with a pointer to the 1700 * interface out which this connection should go. 1701 * 1702 * NOTE: Do not subtract IP option/extension header size nor IPsec 1703 * header size from MSS advertisement. MSS option must hold the maximum 1704 * segment size we can accept, so it must always be: 1705 * max(if mtu) - ip header - tcp header 1706 */ 1707 u_long 1708 tcp_mss_to_advertise(const struct ifnet *ifp, int af) 1709 { 1710 extern u_long in_maxmtu; 1711 u_long mss = 0; 1712 u_long hdrsiz; 1713 1714 /* 1715 * In order to avoid defeating path MTU discovery on the peer, 1716 * we advertise the max MTU of all attached networks as our MSS, 1717 * per RFC 1191, section 3.1. 1718 * 1719 * We provide the option to advertise just the MTU of 1720 * the interface on which we hope this connection will 1721 * be receiving. If we are responding to a SYN, we 1722 * will have a pretty good idea about this, but when 1723 * initiating a connection there is a bit more doubt. 1724 * 1725 * We also need to ensure that loopback has a large enough 1726 * MSS, as the loopback MTU is never included in in_maxmtu. 1727 */ 1728 1729 if (ifp != NULL) 1730 switch (af) { 1731 case AF_INET: 1732 mss = ifp->if_mtu; 1733 break; 1734 #ifdef INET6 1735 case AF_INET6: 1736 mss = IN6_LINKMTU(ifp); 1737 break; 1738 #endif 1739 } 1740 1741 if (tcp_mss_ifmtu == 0) 1742 switch (af) { 1743 case AF_INET: 1744 mss = max(in_maxmtu, mss); 1745 break; 1746 #ifdef INET6 1747 case AF_INET6: 1748 mss = max(in6_maxmtu, mss); 1749 break; 1750 #endif 1751 } 1752 1753 switch (af) { 1754 case AF_INET: 1755 hdrsiz = sizeof(struct ip); 1756 break; 1757 #ifdef INET6 1758 case AF_INET6: 1759 hdrsiz = sizeof(struct ip6_hdr); 1760 break; 1761 #endif 1762 default: 1763 hdrsiz = 0; 1764 break; 1765 } 1766 hdrsiz += sizeof(struct tcphdr); 1767 if (mss > hdrsiz) 1768 mss -= hdrsiz; 1769 1770 mss = max(tcp_mssdflt, mss); 1771 return (mss); 1772 } 1773 1774 /* 1775 * Set connection variables based on the peer's advertised MSS. 1776 * We are passed the TCPCB for the actual connection. If we 1777 * are the server, we are called by the compressed state engine 1778 * when the 3-way handshake is complete. If we are the client, 1779 * we are called when we receive the SYN,ACK from the server. 1780 * 1781 * NOTE: Our advertised MSS value must be initialized in the TCPCB 1782 * before this routine is called! 1783 */ 1784 void 1785 tcp_mss_from_peer(struct tcpcb *tp, int offer) 1786 { 1787 struct socket *so; 1788 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1789 struct rtentry *rt; 1790 #endif 1791 u_long bufsize; 1792 int mss; 1793 1794 #ifdef DIAGNOSTIC 1795 if (tp->t_inpcb && tp->t_in6pcb) 1796 panic("tcp_mss_from_peer: both t_inpcb and t_in6pcb are set"); 1797 #endif 1798 so = NULL; 1799 rt = NULL; 1800 #ifdef INET 1801 if (tp->t_inpcb) { 1802 so = tp->t_inpcb->inp_socket; 1803 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1804 rt = in_pcbrtentry(tp->t_inpcb); 1805 #endif 1806 } 1807 #endif 1808 #ifdef INET6 1809 if (tp->t_in6pcb) { 1810 so = tp->t_in6pcb->in6p_socket; 1811 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1812 rt = in6_pcbrtentry(tp->t_in6pcb); 1813 #endif 1814 } 1815 #endif 1816 1817 /* 1818 * As per RFC1122, use the default MSS value, unless they 1819 * sent us an offer. Do not accept offers less than 256 bytes. 1820 */ 1821 mss = tcp_mssdflt; 1822 if (offer) 1823 mss = offer; 1824 mss = max(mss, 256); /* sanity */ 1825 tp->t_peermss = mss; 1826 mss -= tcp_optlen(tp); 1827 #ifdef INET 1828 if (tp->t_inpcb) 1829 mss -= ip_optlen(tp->t_inpcb); 1830 #endif 1831 #ifdef INET6 1832 if (tp->t_in6pcb) 1833 mss -= ip6_optlen(tp->t_in6pcb); 1834 #endif 1835 1836 /* 1837 * If there's a pipesize, change the socket buffer to that size. 1838 * Make the socket buffer an integral number of MSS units. If 1839 * the MSS is larger than the socket buffer, artificially decrease 1840 * the MSS. 1841 */ 1842 #ifdef RTV_SPIPE 1843 if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0) 1844 bufsize = rt->rt_rmx.rmx_sendpipe; 1845 else 1846 #endif 1847 bufsize = so->so_snd.sb_hiwat; 1848 if (bufsize < mss) 1849 mss = bufsize; 1850 else { 1851 bufsize = roundup(bufsize, mss); 1852 if (bufsize > sb_max) 1853 bufsize = sb_max; 1854 (void) sbreserve(&so->so_snd, bufsize, so); 1855 } 1856 tp->t_segsz = mss; 1857 1858 #ifdef RTV_SSTHRESH 1859 if (rt != NULL && rt->rt_rmx.rmx_ssthresh) { 1860 /* 1861 * There's some sort of gateway or interface buffer 1862 * limit on the path. Use this to set the slow 1863 * start threshold, but set the threshold to no less 1864 * than 2 * MSS. 1865 */ 1866 tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh); 1867 } 1868 #endif 1869 } 1870 1871 /* 1872 * Processing necessary when a TCP connection is established. 1873 */ 1874 void 1875 tcp_established(struct tcpcb *tp) 1876 { 1877 struct socket *so; 1878 #ifdef RTV_RPIPE 1879 struct rtentry *rt; 1880 #endif 1881 u_long bufsize; 1882 1883 #ifdef DIAGNOSTIC 1884 if (tp->t_inpcb && tp->t_in6pcb) 1885 panic("tcp_established: both t_inpcb and t_in6pcb are set"); 1886 #endif 1887 so = NULL; 1888 rt = NULL; 1889 #ifdef INET 1890 if (tp->t_inpcb) { 1891 so = tp->t_inpcb->inp_socket; 1892 #if defined(RTV_RPIPE) 1893 rt = in_pcbrtentry(tp->t_inpcb); 1894 #endif 1895 } 1896 #endif 1897 #ifdef INET6 1898 if (tp->t_in6pcb) { 1899 so = tp->t_in6pcb->in6p_socket; 1900 #if defined(RTV_RPIPE) 1901 rt = in6_pcbrtentry(tp->t_in6pcb); 1902 #endif 1903 } 1904 #endif 1905 1906 tp->t_state = TCPS_ESTABLISHED; 1907 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle); 1908 1909 #ifdef RTV_RPIPE 1910 if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0) 1911 bufsize = rt->rt_rmx.rmx_recvpipe; 1912 else 1913 #endif 1914 bufsize = so->so_rcv.sb_hiwat; 1915 if (bufsize > tp->t_ourmss) { 1916 bufsize = roundup(bufsize, tp->t_ourmss); 1917 if (bufsize > sb_max) 1918 bufsize = sb_max; 1919 (void) sbreserve(&so->so_rcv, bufsize, so); 1920 } 1921 } 1922 1923 /* 1924 * Check if there's an initial rtt or rttvar. Convert from the 1925 * route-table units to scaled multiples of the slow timeout timer. 1926 * Called only during the 3-way handshake. 1927 */ 1928 void 1929 tcp_rmx_rtt(struct tcpcb *tp) 1930 { 1931 #ifdef RTV_RTT 1932 struct rtentry *rt = NULL; 1933 int rtt; 1934 1935 #ifdef DIAGNOSTIC 1936 if (tp->t_inpcb && tp->t_in6pcb) 1937 panic("tcp_rmx_rtt: both t_inpcb and t_in6pcb are set"); 1938 #endif 1939 #ifdef INET 1940 if (tp->t_inpcb) 1941 rt = in_pcbrtentry(tp->t_inpcb); 1942 #endif 1943 #ifdef INET6 1944 if (tp->t_in6pcb) 1945 rt = in6_pcbrtentry(tp->t_in6pcb); 1946 #endif 1947 if (rt == NULL) 1948 return; 1949 1950 if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) { 1951 /* 1952 * XXX The lock bit for MTU indicates that the value 1953 * is also a minimum value; this is subject to time. 1954 */ 1955 if (rt->rt_rmx.rmx_locks & RTV_RTT) 1956 TCPT_RANGESET(tp->t_rttmin, 1957 rtt / (RTM_RTTUNIT / PR_SLOWHZ), 1958 TCPTV_MIN, TCPTV_REXMTMAX); 1959 tp->t_srtt = rtt / 1960 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1961 if (rt->rt_rmx.rmx_rttvar) { 1962 tp->t_rttvar = rt->rt_rmx.rmx_rttvar / 1963 ((RTM_RTTUNIT / PR_SLOWHZ) >> 1964 (TCP_RTTVAR_SHIFT + 2)); 1965 } else { 1966 /* Default variation is +- 1 rtt */ 1967 tp->t_rttvar = 1968 tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT); 1969 } 1970 TCPT_RANGESET(tp->t_rxtcur, 1971 ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2), 1972 tp->t_rttmin, TCPTV_REXMTMAX); 1973 } 1974 #endif 1975 } 1976 1977 tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */ 1978 #if NRND > 0 1979 u_int8_t tcp_iss_secret[16]; /* 128 bits; should be plenty */ 1980 #endif 1981 1982 /* 1983 * Get a new sequence value given a tcp control block 1984 */ 1985 tcp_seq 1986 tcp_new_iss(struct tcpcb *tp, tcp_seq addin) 1987 { 1988 1989 #ifdef INET 1990 if (tp->t_inpcb != NULL) { 1991 return (tcp_new_iss1(&tp->t_inpcb->inp_laddr, 1992 &tp->t_inpcb->inp_faddr, tp->t_inpcb->inp_lport, 1993 tp->t_inpcb->inp_fport, sizeof(tp->t_inpcb->inp_laddr), 1994 addin)); 1995 } 1996 #endif 1997 #ifdef INET6 1998 if (tp->t_in6pcb != NULL) { 1999 return (tcp_new_iss1(&tp->t_in6pcb->in6p_laddr, 2000 &tp->t_in6pcb->in6p_faddr, tp->t_in6pcb->in6p_lport, 2001 tp->t_in6pcb->in6p_fport, sizeof(tp->t_in6pcb->in6p_laddr), 2002 addin)); 2003 } 2004 #endif 2005 /* Not possible. */ 2006 panic("tcp_new_iss"); 2007 } 2008 2009 /* 2010 * This routine actually generates a new TCP initial sequence number. 2011 */ 2012 tcp_seq 2013 tcp_new_iss1(void *laddr, void *faddr, u_int16_t lport, u_int16_t fport, 2014 size_t addrsz, tcp_seq addin) 2015 { 2016 tcp_seq tcp_iss; 2017 2018 #if NRND > 0 2019 static int beenhere; 2020 2021 /* 2022 * If we haven't been here before, initialize our cryptographic 2023 * hash secret. 2024 */ 2025 if (beenhere == 0) { 2026 rnd_extract_data(tcp_iss_secret, sizeof(tcp_iss_secret), 2027 RND_EXTRACT_ANY); 2028 beenhere = 1; 2029 } 2030 2031 if (tcp_do_rfc1948) { 2032 MD5_CTX ctx; 2033 u_int8_t hash[16]; /* XXX MD5 knowledge */ 2034 2035 /* 2036 * Compute the base value of the ISS. It is a hash 2037 * of (saddr, sport, daddr, dport, secret). 2038 */ 2039 MD5Init(&ctx); 2040 2041 MD5Update(&ctx, (u_char *) laddr, addrsz); 2042 MD5Update(&ctx, (u_char *) &lport, sizeof(lport)); 2043 2044 MD5Update(&ctx, (u_char *) faddr, addrsz); 2045 MD5Update(&ctx, (u_char *) &fport, sizeof(fport)); 2046 2047 MD5Update(&ctx, tcp_iss_secret, sizeof(tcp_iss_secret)); 2048 2049 MD5Final(hash, &ctx); 2050 2051 memcpy(&tcp_iss, hash, sizeof(tcp_iss)); 2052 2053 /* 2054 * Now increment our "timer", and add it in to 2055 * the computed value. 2056 * 2057 * XXX Use `addin'? 2058 * XXX TCP_ISSINCR too large to use? 2059 */ 2060 tcp_iss_seq += TCP_ISSINCR; 2061 #ifdef TCPISS_DEBUG 2062 printf("ISS hash 0x%08x, ", tcp_iss); 2063 #endif 2064 tcp_iss += tcp_iss_seq + addin; 2065 #ifdef TCPISS_DEBUG 2066 printf("new ISS 0x%08x\n", tcp_iss); 2067 #endif 2068 } else 2069 #endif /* NRND > 0 */ 2070 { 2071 /* 2072 * Randomize. 2073 */ 2074 #if NRND > 0 2075 rnd_extract_data(&tcp_iss, sizeof(tcp_iss), RND_EXTRACT_ANY); 2076 #else 2077 tcp_iss = arc4random(); 2078 #endif 2079 2080 /* 2081 * If we were asked to add some amount to a known value, 2082 * we will take a random value obtained above, mask off 2083 * the upper bits, and add in the known value. We also 2084 * add in a constant to ensure that we are at least a 2085 * certain distance from the original value. 2086 * 2087 * This is used when an old connection is in timed wait 2088 * and we have a new one coming in, for instance. 2089 */ 2090 if (addin != 0) { 2091 #ifdef TCPISS_DEBUG 2092 printf("Random %08x, ", tcp_iss); 2093 #endif 2094 tcp_iss &= TCP_ISS_RANDOM_MASK; 2095 tcp_iss += addin + TCP_ISSINCR; 2096 #ifdef TCPISS_DEBUG 2097 printf("Old ISS %08x, ISS %08x\n", addin, tcp_iss); 2098 #endif 2099 } else { 2100 tcp_iss &= TCP_ISS_RANDOM_MASK; 2101 tcp_iss += tcp_iss_seq; 2102 tcp_iss_seq += TCP_ISSINCR; 2103 #ifdef TCPISS_DEBUG 2104 printf("ISS %08x\n", tcp_iss); 2105 #endif 2106 } 2107 } 2108 2109 if (tcp_compat_42) { 2110 /* 2111 * Limit it to the positive range for really old TCP 2112 * implementations. 2113 * Just AND off the top bit instead of checking if 2114 * is set first - saves a branch 50% of the time. 2115 */ 2116 tcp_iss &= 0x7fffffff; /* XXX */ 2117 } 2118 2119 return (tcp_iss); 2120 } 2121 2122 #if defined(IPSEC) || defined(FAST_IPSEC) 2123 /* compute ESP/AH header size for TCP, including outer IP header. */ 2124 size_t 2125 ipsec4_hdrsiz_tcp(struct tcpcb *tp) 2126 { 2127 struct inpcb *inp; 2128 size_t hdrsiz; 2129 2130 /* XXX mapped addr case (tp->t_in6pcb) */ 2131 if (!tp || !tp->t_template || !(inp = tp->t_inpcb)) 2132 return 0; 2133 switch (tp->t_family) { 2134 case AF_INET: 2135 /* XXX: should use currect direction. */ 2136 hdrsiz = ipsec4_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, inp); 2137 break; 2138 default: 2139 hdrsiz = 0; 2140 break; 2141 } 2142 2143 return hdrsiz; 2144 } 2145 2146 #ifdef INET6 2147 size_t 2148 ipsec6_hdrsiz_tcp(struct tcpcb *tp) 2149 { 2150 struct in6pcb *in6p; 2151 size_t hdrsiz; 2152 2153 if (!tp || !tp->t_template || !(in6p = tp->t_in6pcb)) 2154 return 0; 2155 switch (tp->t_family) { 2156 case AF_INET6: 2157 /* XXX: should use currect direction. */ 2158 hdrsiz = ipsec6_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, in6p); 2159 break; 2160 case AF_INET: 2161 /* mapped address case - tricky */ 2162 default: 2163 hdrsiz = 0; 2164 break; 2165 } 2166 2167 return hdrsiz; 2168 } 2169 #endif 2170 #endif /*IPSEC*/ 2171 2172 /* 2173 * Determine the length of the TCP options for this connection. 2174 * 2175 * XXX: What do we do for SACK, when we add that? Just reserve 2176 * all of the space? Otherwise we can't exactly be incrementing 2177 * cwnd by an amount that varies depending on the amount we last 2178 * had to SACK! 2179 */ 2180 2181 u_int 2182 tcp_optlen(struct tcpcb *tp) 2183 { 2184 u_int optlen; 2185 2186 optlen = 0; 2187 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 2188 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 2189 optlen += TCPOLEN_TSTAMP_APPA; 2190 2191 #ifdef TCP_SIGNATURE 2192 #if defined(INET6) && defined(FAST_IPSEC) 2193 if (tp->t_family == AF_INET) 2194 #endif 2195 if (tp->t_flags & TF_SIGNATURE) 2196 optlen += TCPOLEN_SIGNATURE + 2; 2197 #endif /* TCP_SIGNATURE */ 2198 2199 return optlen; 2200 } 2201
Indexes created Tue Sep 23 02:09:52 GMT 2025