tcp_subr.c revision 1.192
1 /* $NetBSD: tcp_subr.c,v 1.192 2005/07/19 17:00:02 christos 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 1.192 2005/07/19 17:00:02 christos 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_sack_tp_maxholes = 32; 204 int tcp_sack_globalmaxholes = 1024; 205 int tcp_sack_globalholes = 0; 206 207 208 /* tcb hash */ 209 #ifndef TCBHASHSIZE 210 #define TCBHASHSIZE 128 211 #endif 212 int tcbhashsize = TCBHASHSIZE; 213 214 /* syn hash parameters */ 215 #define TCP_SYN_HASH_SIZE 293 216 #define TCP_SYN_BUCKET_SIZE 35 217 int tcp_syn_cache_size = TCP_SYN_HASH_SIZE; 218 int tcp_syn_cache_limit = TCP_SYN_HASH_SIZE*TCP_SYN_BUCKET_SIZE; 219 int tcp_syn_bucket_limit = 3*TCP_SYN_BUCKET_SIZE; 220 struct syn_cache_head tcp_syn_cache[TCP_SYN_HASH_SIZE]; 221 222 int tcp_freeq(struct tcpcb *); 223 224 #ifdef INET 225 void tcp_mtudisc_callback(struct in_addr); 226 #endif 227 #ifdef INET6 228 void tcp6_mtudisc_callback(struct in6_addr *); 229 #endif 230 231 #ifdef INET6 232 void tcp6_mtudisc(struct in6pcb *, int); 233 #endif 234 235 POOL_INIT(tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl", NULL); 236 237 #ifdef TCP_CSUM_COUNTERS 238 #include <sys/device.h> 239 240 struct evcnt tcp_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 241 NULL, "tcp", "hwcsum bad"); 242 struct evcnt tcp_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 243 NULL, "tcp", "hwcsum ok"); 244 struct evcnt tcp_hwcsum_data = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 245 NULL, "tcp", "hwcsum data"); 246 struct evcnt tcp_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 247 NULL, "tcp", "swcsum"); 248 249 EVCNT_ATTACH_STATIC(tcp_hwcsum_bad); 250 EVCNT_ATTACH_STATIC(tcp_hwcsum_ok); 251 EVCNT_ATTACH_STATIC(tcp_hwcsum_data); 252 EVCNT_ATTACH_STATIC(tcp_swcsum); 253 #endif /* TCP_CSUM_COUNTERS */ 254 255 256 #ifdef TCP_OUTPUT_COUNTERS 257 #include <sys/device.h> 258 259 struct evcnt tcp_output_bigheader = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 260 NULL, "tcp", "output big header"); 261 struct evcnt tcp_output_predict_hit = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 262 NULL, "tcp", "output predict hit"); 263 struct evcnt tcp_output_predict_miss = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 264 NULL, "tcp", "output predict miss"); 265 struct evcnt tcp_output_copysmall = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 266 NULL, "tcp", "output copy small"); 267 struct evcnt tcp_output_copybig = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 268 NULL, "tcp", "output copy big"); 269 struct evcnt tcp_output_refbig = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 270 NULL, "tcp", "output reference big"); 271 272 EVCNT_ATTACH_STATIC(tcp_output_bigheader); 273 EVCNT_ATTACH_STATIC(tcp_output_predict_hit); 274 EVCNT_ATTACH_STATIC(tcp_output_predict_miss); 275 EVCNT_ATTACH_STATIC(tcp_output_copysmall); 276 EVCNT_ATTACH_STATIC(tcp_output_copybig); 277 EVCNT_ATTACH_STATIC(tcp_output_refbig); 278 279 #endif /* TCP_OUTPUT_COUNTERS */ 280 281 #ifdef TCP_REASS_COUNTERS 282 #include <sys/device.h> 283 284 struct evcnt tcp_reass_ = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 285 NULL, "tcp_reass", "calls"); 286 struct evcnt tcp_reass_empty = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 287 &tcp_reass_, "tcp_reass", "insert into empty queue"); 288 struct evcnt tcp_reass_iteration[8] = { 289 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", ">7 iterations"), 290 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "1 iteration"), 291 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "2 iterations"), 292 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "3 iterations"), 293 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "4 iterations"), 294 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "5 iterations"), 295 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "6 iterations"), 296 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "7 iterations"), 297 }; 298 struct evcnt tcp_reass_prependfirst = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 299 &tcp_reass_, "tcp_reass", "prepend to first"); 300 struct evcnt tcp_reass_prepend = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 301 &tcp_reass_, "tcp_reass", "prepend"); 302 struct evcnt tcp_reass_insert = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 303 &tcp_reass_, "tcp_reass", "insert"); 304 struct evcnt tcp_reass_inserttail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 305 &tcp_reass_, "tcp_reass", "insert at tail"); 306 struct evcnt tcp_reass_append = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 307 &tcp_reass_, "tcp_reass", "append"); 308 struct evcnt tcp_reass_appendtail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 309 &tcp_reass_, "tcp_reass", "append to tail fragment"); 310 struct evcnt tcp_reass_overlaptail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 311 &tcp_reass_, "tcp_reass", "overlap at end"); 312 struct evcnt tcp_reass_overlapfront = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 313 &tcp_reass_, "tcp_reass", "overlap at start"); 314 struct evcnt tcp_reass_segdup = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 315 &tcp_reass_, "tcp_reass", "duplicate segment"); 316 struct evcnt tcp_reass_fragdup = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 317 &tcp_reass_, "tcp_reass", "duplicate fragment"); 318 319 EVCNT_ATTACH_STATIC(tcp_reass_); 320 EVCNT_ATTACH_STATIC(tcp_reass_empty); 321 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 0); 322 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 1); 323 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 2); 324 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 3); 325 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 4); 326 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 5); 327 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 6); 328 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 7); 329 EVCNT_ATTACH_STATIC(tcp_reass_prependfirst); 330 EVCNT_ATTACH_STATIC(tcp_reass_prepend); 331 EVCNT_ATTACH_STATIC(tcp_reass_insert); 332 EVCNT_ATTACH_STATIC(tcp_reass_inserttail); 333 EVCNT_ATTACH_STATIC(tcp_reass_append); 334 EVCNT_ATTACH_STATIC(tcp_reass_appendtail); 335 EVCNT_ATTACH_STATIC(tcp_reass_overlaptail); 336 EVCNT_ATTACH_STATIC(tcp_reass_overlapfront); 337 EVCNT_ATTACH_STATIC(tcp_reass_segdup); 338 EVCNT_ATTACH_STATIC(tcp_reass_fragdup); 339 340 #endif /* TCP_REASS_COUNTERS */ 341 342 #ifdef MBUFTRACE 343 struct mowner tcp_mowner = { "tcp" }; 344 struct mowner tcp_rx_mowner = { "tcp", "rx" }; 345 struct mowner tcp_tx_mowner = { "tcp", "tx" }; 346 #endif 347 348 /* 349 * Tcp initialization 350 */ 351 void 352 tcp_init(void) 353 { 354 int hlen; 355 356 /* Initialize the TCPCB template. */ 357 tcp_tcpcb_template(); 358 359 in_pcbinit(&tcbtable, tcbhashsize, tcbhashsize); 360 361 hlen = sizeof(struct ip) + sizeof(struct tcphdr); 362 #ifdef INET6 363 if (sizeof(struct ip) < sizeof(struct ip6_hdr)) 364 hlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 365 #endif 366 if (max_protohdr < hlen) 367 max_protohdr = hlen; 368 if (max_linkhdr + hlen > MHLEN) 369 panic("tcp_init"); 370 371 #ifdef INET 372 icmp_mtudisc_callback_register(tcp_mtudisc_callback); 373 #endif 374 #ifdef INET6 375 icmp6_mtudisc_callback_register(tcp6_mtudisc_callback); 376 #endif 377 378 /* Initialize timer state. */ 379 tcp_timer_init(); 380 381 /* Initialize the compressed state engine. */ 382 syn_cache_init(); 383 384 MOWNER_ATTACH(&tcp_tx_mowner); 385 MOWNER_ATTACH(&tcp_rx_mowner); 386 MOWNER_ATTACH(&tcp_mowner); 387 } 388 389 /* 390 * Create template to be used to send tcp packets on a connection. 391 * Call after host entry created, allocates an mbuf and fills 392 * in a skeletal tcp/ip header, minimizing the amount of work 393 * necessary when the connection is used. 394 */ 395 struct mbuf * 396 tcp_template(struct tcpcb *tp) 397 { 398 struct inpcb *inp = tp->t_inpcb; 399 #ifdef INET6 400 struct in6pcb *in6p = tp->t_in6pcb; 401 #endif 402 struct tcphdr *n; 403 struct mbuf *m; 404 int hlen; 405 406 switch (tp->t_family) { 407 case AF_INET: 408 hlen = sizeof(struct ip); 409 if (inp) 410 break; 411 #ifdef INET6 412 if (in6p) { 413 /* mapped addr case */ 414 if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_laddr) 415 && IN6_IS_ADDR_V4MAPPED(&in6p->in6p_faddr)) 416 break; 417 } 418 #endif 419 return NULL; /*EINVAL*/ 420 #ifdef INET6 421 case AF_INET6: 422 hlen = sizeof(struct ip6_hdr); 423 if (in6p) { 424 /* more sainty check? */ 425 break; 426 } 427 return NULL; /*EINVAL*/ 428 #endif 429 default: 430 hlen = 0; /*pacify gcc*/ 431 return NULL; /*EAFNOSUPPORT*/ 432 } 433 #ifdef DIAGNOSTIC 434 if (hlen + sizeof(struct tcphdr) > MCLBYTES) 435 panic("mclbytes too small for t_template"); 436 #endif 437 m = tp->t_template; 438 if (m && m->m_len == hlen + sizeof(struct tcphdr)) 439 ; 440 else { 441 if (m) 442 m_freem(m); 443 m = tp->t_template = NULL; 444 MGETHDR(m, M_DONTWAIT, MT_HEADER); 445 if (m && hlen + sizeof(struct tcphdr) > MHLEN) { 446 MCLGET(m, M_DONTWAIT); 447 if ((m->m_flags & M_EXT) == 0) { 448 m_free(m); 449 m = NULL; 450 } 451 } 452 if (m == NULL) 453 return NULL; 454 MCLAIM(m, &tcp_mowner); 455 m->m_pkthdr.len = m->m_len = hlen + sizeof(struct tcphdr); 456 } 457 458 bzero(mtod(m, caddr_t), m->m_len); 459 460 n = (struct tcphdr *)(mtod(m, caddr_t) + hlen); 461 462 switch (tp->t_family) { 463 case AF_INET: 464 { 465 struct ipovly *ipov; 466 mtod(m, struct ip *)->ip_v = 4; 467 mtod(m, struct ip *)->ip_hl = hlen >> 2; 468 ipov = mtod(m, struct ipovly *); 469 ipov->ih_pr = IPPROTO_TCP; 470 ipov->ih_len = htons(sizeof(struct tcphdr)); 471 if (inp) { 472 ipov->ih_src = inp->inp_laddr; 473 ipov->ih_dst = inp->inp_faddr; 474 } 475 #ifdef INET6 476 else if (in6p) { 477 /* mapped addr case */ 478 bcopy(&in6p->in6p_laddr.s6_addr32[3], &ipov->ih_src, 479 sizeof(ipov->ih_src)); 480 bcopy(&in6p->in6p_faddr.s6_addr32[3], &ipov->ih_dst, 481 sizeof(ipov->ih_dst)); 482 } 483 #endif 484 /* 485 * Compute the pseudo-header portion of the checksum 486 * now. We incrementally add in the TCP option and 487 * payload lengths later, and then compute the TCP 488 * checksum right before the packet is sent off onto 489 * the wire. 490 */ 491 n->th_sum = in_cksum_phdr(ipov->ih_src.s_addr, 492 ipov->ih_dst.s_addr, 493 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 494 break; 495 } 496 #ifdef INET6 497 case AF_INET6: 498 { 499 struct ip6_hdr *ip6; 500 mtod(m, struct ip *)->ip_v = 6; 501 ip6 = mtod(m, struct ip6_hdr *); 502 ip6->ip6_nxt = IPPROTO_TCP; 503 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 504 ip6->ip6_src = in6p->in6p_laddr; 505 ip6->ip6_dst = in6p->in6p_faddr; 506 ip6->ip6_flow = in6p->in6p_flowinfo & IPV6_FLOWINFO_MASK; 507 if (ip6_auto_flowlabel) { 508 ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK; 509 ip6->ip6_flow |= 510 (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK); 511 } 512 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 513 ip6->ip6_vfc |= IPV6_VERSION; 514 515 /* 516 * Compute the pseudo-header portion of the checksum 517 * now. We incrementally add in the TCP option and 518 * payload lengths later, and then compute the TCP 519 * checksum right before the packet is sent off onto 520 * the wire. 521 */ 522 n->th_sum = in6_cksum_phdr(&in6p->in6p_laddr, 523 &in6p->in6p_faddr, htonl(sizeof(struct tcphdr)), 524 htonl(IPPROTO_TCP)); 525 break; 526 } 527 #endif 528 } 529 if (inp) { 530 n->th_sport = inp->inp_lport; 531 n->th_dport = inp->inp_fport; 532 } 533 #ifdef INET6 534 else if (in6p) { 535 n->th_sport = in6p->in6p_lport; 536 n->th_dport = in6p->in6p_fport; 537 } 538 #endif 539 n->th_seq = 0; 540 n->th_ack = 0; 541 n->th_x2 = 0; 542 n->th_off = 5; 543 n->th_flags = 0; 544 n->th_win = 0; 545 n->th_urp = 0; 546 return (m); 547 } 548 549 /* 550 * Send a single message to the TCP at address specified by 551 * the given TCP/IP header. If m == 0, then we make a copy 552 * of the tcpiphdr at ti and send directly to the addressed host. 553 * This is used to force keep alive messages out using the TCP 554 * template for a connection tp->t_template. If flags are given 555 * then we send a message back to the TCP which originated the 556 * segment ti, and discard the mbuf containing it and any other 557 * attached mbufs. 558 * 559 * In any case the ack and sequence number of the transmitted 560 * segment are as specified by the parameters. 561 */ 562 int 563 tcp_respond(struct tcpcb *tp, struct mbuf *template, struct mbuf *m, 564 struct tcphdr *th0, tcp_seq ack, tcp_seq seq, int flags) 565 { 566 struct route *ro; 567 int error, tlen, win = 0; 568 int hlen; 569 struct ip *ip; 570 #ifdef INET6 571 struct ip6_hdr *ip6; 572 #endif 573 int family; /* family on packet, not inpcb/in6pcb! */ 574 struct tcphdr *th; 575 struct socket *so; 576 577 if (tp != NULL && (flags & TH_RST) == 0) { 578 #ifdef DIAGNOSTIC 579 if (tp->t_inpcb && tp->t_in6pcb) 580 panic("tcp_respond: both t_inpcb and t_in6pcb are set"); 581 #endif 582 #ifdef INET 583 if (tp->t_inpcb) 584 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 585 #endif 586 #ifdef INET6 587 if (tp->t_in6pcb) 588 win = sbspace(&tp->t_in6pcb->in6p_socket->so_rcv); 589 #endif 590 } 591 592 th = NULL; /* Quell uninitialized warning */ 593 ip = NULL; 594 #ifdef INET6 595 ip6 = NULL; 596 #endif 597 if (m == 0) { 598 if (!template) 599 return EINVAL; 600 601 /* get family information from template */ 602 switch (mtod(template, struct ip *)->ip_v) { 603 case 4: 604 family = AF_INET; 605 hlen = sizeof(struct ip); 606 break; 607 #ifdef INET6 608 case 6: 609 family = AF_INET6; 610 hlen = sizeof(struct ip6_hdr); 611 break; 612 #endif 613 default: 614 return EAFNOSUPPORT; 615 } 616 617 MGETHDR(m, M_DONTWAIT, MT_HEADER); 618 if (m) { 619 MCLAIM(m, &tcp_tx_mowner); 620 MCLGET(m, M_DONTWAIT); 621 if ((m->m_flags & M_EXT) == 0) { 622 m_free(m); 623 m = NULL; 624 } 625 } 626 if (m == NULL) 627 return (ENOBUFS); 628 629 if (tcp_compat_42) 630 tlen = 1; 631 else 632 tlen = 0; 633 634 m->m_data += max_linkhdr; 635 bcopy(mtod(template, caddr_t), mtod(m, caddr_t), 636 template->m_len); 637 switch (family) { 638 case AF_INET: 639 ip = mtod(m, struct ip *); 640 th = (struct tcphdr *)(ip + 1); 641 break; 642 #ifdef INET6 643 case AF_INET6: 644 ip6 = mtod(m, struct ip6_hdr *); 645 th = (struct tcphdr *)(ip6 + 1); 646 break; 647 #endif 648 #if 0 649 default: 650 /* noone will visit here */ 651 m_freem(m); 652 return EAFNOSUPPORT; 653 #endif 654 } 655 flags = TH_ACK; 656 } else { 657 658 if ((m->m_flags & M_PKTHDR) == 0) { 659 #if 0 660 printf("non PKTHDR to tcp_respond\n"); 661 #endif 662 m_freem(m); 663 return EINVAL; 664 } 665 #ifdef DIAGNOSTIC 666 if (!th0) 667 panic("th0 == NULL in tcp_respond"); 668 #endif 669 670 /* get family information from m */ 671 switch (mtod(m, struct ip *)->ip_v) { 672 case 4: 673 family = AF_INET; 674 hlen = sizeof(struct ip); 675 ip = mtod(m, struct ip *); 676 break; 677 #ifdef INET6 678 case 6: 679 family = AF_INET6; 680 hlen = sizeof(struct ip6_hdr); 681 ip6 = mtod(m, struct ip6_hdr *); 682 break; 683 #endif 684 default: 685 m_freem(m); 686 return EAFNOSUPPORT; 687 } 688 /* clear h/w csum flags inherited from rx packet */ 689 m->m_pkthdr.csum_flags = 0; 690 691 if ((flags & TH_SYN) == 0 || sizeof(*th0) > (th0->th_off << 2)) 692 tlen = sizeof(*th0); 693 else 694 tlen = th0->th_off << 2; 695 696 if (m->m_len > hlen + tlen && (m->m_flags & M_EXT) == 0 && 697 mtod(m, caddr_t) + hlen == (caddr_t)th0) { 698 m->m_len = hlen + tlen; 699 m_freem(m->m_next); 700 m->m_next = NULL; 701 } else { 702 struct mbuf *n; 703 704 #ifdef DIAGNOSTIC 705 if (max_linkhdr + hlen + tlen > MCLBYTES) { 706 m_freem(m); 707 return EMSGSIZE; 708 } 709 #endif 710 MGETHDR(n, M_DONTWAIT, MT_HEADER); 711 if (n && max_linkhdr + hlen + tlen > MHLEN) { 712 MCLGET(n, M_DONTWAIT); 713 if ((n->m_flags & M_EXT) == 0) { 714 m_freem(n); 715 n = NULL; 716 } 717 } 718 if (!n) { 719 m_freem(m); 720 return ENOBUFS; 721 } 722 723 MCLAIM(n, &tcp_tx_mowner); 724 n->m_data += max_linkhdr; 725 n->m_len = hlen + tlen; 726 m_copyback(n, 0, hlen, mtod(m, caddr_t)); 727 m_copyback(n, hlen, tlen, (caddr_t)th0); 728 729 m_freem(m); 730 m = n; 731 n = NULL; 732 } 733 734 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 735 switch (family) { 736 case AF_INET: 737 ip = mtod(m, struct ip *); 738 th = (struct tcphdr *)(ip + 1); 739 ip->ip_p = IPPROTO_TCP; 740 xchg(ip->ip_dst, ip->ip_src, struct in_addr); 741 ip->ip_p = IPPROTO_TCP; 742 break; 743 #ifdef INET6 744 case AF_INET6: 745 ip6 = mtod(m, struct ip6_hdr *); 746 th = (struct tcphdr *)(ip6 + 1); 747 ip6->ip6_nxt = IPPROTO_TCP; 748 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 749 ip6->ip6_nxt = IPPROTO_TCP; 750 break; 751 #endif 752 #if 0 753 default: 754 /* noone will visit here */ 755 m_freem(m); 756 return EAFNOSUPPORT; 757 #endif 758 } 759 xchg(th->th_dport, th->th_sport, u_int16_t); 760 #undef xchg 761 tlen = 0; /*be friendly with the following code*/ 762 } 763 th->th_seq = htonl(seq); 764 th->th_ack = htonl(ack); 765 th->th_x2 = 0; 766 if ((flags & TH_SYN) == 0) { 767 if (tp) 768 win >>= tp->rcv_scale; 769 if (win > TCP_MAXWIN) 770 win = TCP_MAXWIN; 771 th->th_win = htons((u_int16_t)win); 772 th->th_off = sizeof (struct tcphdr) >> 2; 773 tlen += sizeof(*th); 774 } else 775 tlen += th->th_off << 2; 776 m->m_len = hlen + tlen; 777 m->m_pkthdr.len = hlen + tlen; 778 m->m_pkthdr.rcvif = (struct ifnet *) 0; 779 th->th_flags = flags; 780 th->th_urp = 0; 781 782 switch (family) { 783 #ifdef INET 784 case AF_INET: 785 { 786 struct ipovly *ipov = (struct ipovly *)ip; 787 bzero(ipov->ih_x1, sizeof ipov->ih_x1); 788 ipov->ih_len = htons((u_int16_t)tlen); 789 790 th->th_sum = 0; 791 th->th_sum = in_cksum(m, hlen + tlen); 792 ip->ip_len = htons(hlen + tlen); 793 ip->ip_ttl = ip_defttl; 794 break; 795 } 796 #endif 797 #ifdef INET6 798 case AF_INET6: 799 { 800 th->th_sum = 0; 801 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), 802 tlen); 803 ip6->ip6_plen = htons(tlen); 804 if (tp && tp->t_in6pcb) { 805 struct ifnet *oifp; 806 ro = (struct route *)&tp->t_in6pcb->in6p_route; 807 oifp = ro->ro_rt ? ro->ro_rt->rt_ifp : NULL; 808 ip6->ip6_hlim = in6_selecthlim(tp->t_in6pcb, oifp); 809 } else 810 ip6->ip6_hlim = ip6_defhlim; 811 ip6->ip6_flow &= ~IPV6_FLOWINFO_MASK; 812 if (ip6_auto_flowlabel) { 813 ip6->ip6_flow |= 814 (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK); 815 } 816 break; 817 } 818 #endif 819 } 820 821 if (tp && tp->t_inpcb) 822 so = tp->t_inpcb->inp_socket; 823 #ifdef INET6 824 else if (tp && tp->t_in6pcb) 825 so = tp->t_in6pcb->in6p_socket; 826 #endif 827 else 828 so = NULL; 829 830 if (tp != NULL && tp->t_inpcb != NULL) { 831 ro = &tp->t_inpcb->inp_route; 832 #ifdef DIAGNOSTIC 833 if (family != AF_INET) 834 panic("tcp_respond: address family mismatch"); 835 if (!in_hosteq(ip->ip_dst, tp->t_inpcb->inp_faddr)) { 836 panic("tcp_respond: ip_dst %x != inp_faddr %x", 837 ntohl(ip->ip_dst.s_addr), 838 ntohl(tp->t_inpcb->inp_faddr.s_addr)); 839 } 840 #endif 841 } 842 #ifdef INET6 843 else if (tp != NULL && tp->t_in6pcb != NULL) { 844 ro = (struct route *)&tp->t_in6pcb->in6p_route; 845 #ifdef DIAGNOSTIC 846 if (family == AF_INET) { 847 if (!IN6_IS_ADDR_V4MAPPED(&tp->t_in6pcb->in6p_faddr)) 848 panic("tcp_respond: not mapped addr"); 849 if (bcmp(&ip->ip_dst, 850 &tp->t_in6pcb->in6p_faddr.s6_addr32[3], 851 sizeof(ip->ip_dst)) != 0) { 852 panic("tcp_respond: ip_dst != in6p_faddr"); 853 } 854 } else if (family == AF_INET6) { 855 if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, 856 &tp->t_in6pcb->in6p_faddr)) 857 panic("tcp_respond: ip6_dst != in6p_faddr"); 858 } else 859 panic("tcp_respond: address family mismatch"); 860 #endif 861 } 862 #endif 863 else 864 ro = NULL; 865 866 switch (family) { 867 #ifdef INET 868 case AF_INET: 869 error = ip_output(m, NULL, ro, 870 (tp && tp->t_mtudisc ? IP_MTUDISC : 0), 871 (struct ip_moptions *)0, so); 872 break; 873 #endif 874 #ifdef INET6 875 case AF_INET6: 876 error = ip6_output(m, NULL, (struct route_in6 *)ro, 0, 877 (struct ip6_moptions *)0, so, NULL); 878 break; 879 #endif 880 default: 881 error = EAFNOSUPPORT; 882 break; 883 } 884 885 return (error); 886 } 887 888 /* 889 * Template TCPCB. Rather than zeroing a new TCPCB and initializing 890 * a bunch of members individually, we maintain this template for the 891 * static and mostly-static components of the TCPCB, and copy it into 892 * the new TCPCB instead. 893 */ 894 static struct tcpcb tcpcb_template = { 895 /* 896 * If TCP_NTIMERS ever changes, we'll need to update this 897 * initializer. 898 */ 899 .t_timer = { 900 CALLOUT_INITIALIZER, 901 CALLOUT_INITIALIZER, 902 CALLOUT_INITIALIZER, 903 CALLOUT_INITIALIZER, 904 }, 905 .t_delack_ch = CALLOUT_INITIALIZER, 906 907 .t_srtt = TCPTV_SRTTBASE, 908 .t_rttmin = TCPTV_MIN, 909 910 .snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT, 911 .snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT, 912 .snd_numholes = 0, 913 914 .t_partialacks = -1, 915 }; 916 917 /* 918 * Updates the TCPCB template whenever a parameter that would affect 919 * the template is changed. 920 */ 921 void 922 tcp_tcpcb_template(void) 923 { 924 struct tcpcb *tp = &tcpcb_template; 925 int flags; 926 927 tp->t_peermss = tcp_mssdflt; 928 tp->t_ourmss = tcp_mssdflt; 929 tp->t_segsz = tcp_mssdflt; 930 931 flags = 0; 932 if (tcp_do_rfc1323 && tcp_do_win_scale) 933 flags |= TF_REQ_SCALE; 934 if (tcp_do_rfc1323 && tcp_do_timestamps) 935 flags |= TF_REQ_TSTMP; 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 TAILQ_INIT(&tp->snd_holes); 969 LIST_INIT(&tp->t_sc); /* XXX can template this */ 970 971 /* Don't sweat this loop; hopefully the compiler will unroll it. */ 972 for (i = 0; i < TCPT_NTIMERS; i++) 973 TCP_TIMER_INIT(tp, i); 974 975 switch (family) { 976 case AF_INET: 977 { 978 struct inpcb *inp = (struct inpcb *)aux; 979 980 inp->inp_ip.ip_ttl = ip_defttl; 981 inp->inp_ppcb = (caddr_t)tp; 982 983 tp->t_inpcb = inp; 984 tp->t_mtudisc = ip_mtudisc; 985 break; 986 } 987 #ifdef INET6 988 case AF_INET6: 989 { 990 struct in6pcb *in6p = (struct in6pcb *)aux; 991 992 in6p->in6p_ip6.ip6_hlim = in6_selecthlim(in6p, 993 in6p->in6p_route.ro_rt ? in6p->in6p_route.ro_rt->rt_ifp 994 : NULL); 995 in6p->in6p_ppcb = (caddr_t)tp; 996 997 tp->t_in6pcb = in6p; 998 /* for IPv6, always try to run path MTU discovery */ 999 tp->t_mtudisc = 1; 1000 break; 1001 } 1002 #endif /* INET6 */ 1003 default: 1004 pool_put(&tcpcb_pool, tp); 1005 return (NULL); 1006 } 1007 1008 /* 1009 * Initialize our timebase. When we send timestamps, we take 1010 * the delta from tcp_now -- this means each connection always 1011 * gets a timebase of 0, which makes it, among other things, 1012 * more difficult to determine how long a system has been up, 1013 * and thus how many TCP sequence increments have occurred. 1014 */ 1015 tp->ts_timebase = tcp_now; 1016 1017 return (tp); 1018 } 1019 1020 /* 1021 * Drop a TCP connection, reporting 1022 * the specified error. If connection is synchronized, 1023 * then send a RST to peer. 1024 */ 1025 struct tcpcb * 1026 tcp_drop(struct tcpcb *tp, int errno) 1027 { 1028 struct socket *so = NULL; 1029 1030 #ifdef DIAGNOSTIC 1031 if (tp->t_inpcb && tp->t_in6pcb) 1032 panic("tcp_drop: both t_inpcb and t_in6pcb are set"); 1033 #endif 1034 #ifdef INET 1035 if (tp->t_inpcb) 1036 so = tp->t_inpcb->inp_socket; 1037 #endif 1038 #ifdef INET6 1039 if (tp->t_in6pcb) 1040 so = tp->t_in6pcb->in6p_socket; 1041 #endif 1042 if (!so) 1043 return NULL; 1044 1045 if (TCPS_HAVERCVDSYN(tp->t_state)) { 1046 tp->t_state = TCPS_CLOSED; 1047 (void) tcp_output(tp); 1048 tcpstat.tcps_drops++; 1049 } else 1050 tcpstat.tcps_conndrops++; 1051 if (errno == ETIMEDOUT && tp->t_softerror) 1052 errno = tp->t_softerror; 1053 so->so_error = errno; 1054 return (tcp_close(tp)); 1055 } 1056 1057 /* 1058 * Return whether this tcpcb is marked as dead, indicating 1059 * to the calling timer function that no further action should 1060 * be taken, as we are about to release this tcpcb. The release 1061 * of the storage will be done if this is the last timer running. 1062 * 1063 * This should be called from the callout handler function after 1064 * callout_ack() is done, so that the number of invoking timer 1065 * functions is 0. 1066 */ 1067 int 1068 tcp_isdead(struct tcpcb *tp) 1069 { 1070 int dead = (tp->t_flags & TF_DEAD); 1071 1072 if (__predict_false(dead)) { 1073 if (tcp_timers_invoking(tp) > 0) 1074 /* not quite there yet -- count separately? */ 1075 return dead; 1076 tcpstat.tcps_delayed_free++; 1077 pool_put(&tcpcb_pool, tp); 1078 } 1079 return dead; 1080 } 1081 1082 /* 1083 * Close a TCP control block: 1084 * discard all space held by the tcp 1085 * discard internet protocol block 1086 * wake up any sleepers 1087 */ 1088 struct tcpcb * 1089 tcp_close(struct tcpcb *tp) 1090 { 1091 struct inpcb *inp; 1092 #ifdef INET6 1093 struct in6pcb *in6p; 1094 #endif 1095 struct socket *so; 1096 #ifdef RTV_RTT 1097 struct rtentry *rt; 1098 #endif 1099 struct route *ro; 1100 1101 inp = tp->t_inpcb; 1102 #ifdef INET6 1103 in6p = tp->t_in6pcb; 1104 #endif 1105 so = NULL; 1106 ro = NULL; 1107 if (inp) { 1108 so = inp->inp_socket; 1109 ro = &inp->inp_route; 1110 } 1111 #ifdef INET6 1112 else if (in6p) { 1113 so = in6p->in6p_socket; 1114 ro = (struct route *)&in6p->in6p_route; 1115 } 1116 #endif 1117 1118 #ifdef RTV_RTT 1119 /* 1120 * If we sent enough data to get some meaningful characteristics, 1121 * save them in the routing entry. 'Enough' is arbitrarily 1122 * defined as the sendpipesize (default 4K) * 16. This would 1123 * give us 16 rtt samples assuming we only get one sample per 1124 * window (the usual case on a long haul net). 16 samples is 1125 * enough for the srtt filter to converge to within 5% of the correct 1126 * value; fewer samples and we could save a very bogus rtt. 1127 * 1128 * Don't update the default route's characteristics and don't 1129 * update anything that the user "locked". 1130 */ 1131 if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) && 1132 ro && (rt = ro->ro_rt) && 1133 !in_nullhost(satosin(rt_key(rt))->sin_addr)) { 1134 u_long i = 0; 1135 1136 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 1137 i = tp->t_srtt * 1138 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1139 if (rt->rt_rmx.rmx_rtt && i) 1140 /* 1141 * filter this update to half the old & half 1142 * the new values, converting scale. 1143 * See route.h and tcp_var.h for a 1144 * description of the scaling constants. 1145 */ 1146 rt->rt_rmx.rmx_rtt = 1147 (rt->rt_rmx.rmx_rtt + i) / 2; 1148 else 1149 rt->rt_rmx.rmx_rtt = i; 1150 } 1151 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 1152 i = tp->t_rttvar * 1153 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2)); 1154 if (rt->rt_rmx.rmx_rttvar && i) 1155 rt->rt_rmx.rmx_rttvar = 1156 (rt->rt_rmx.rmx_rttvar + i) / 2; 1157 else 1158 rt->rt_rmx.rmx_rttvar = i; 1159 } 1160 /* 1161 * update the pipelimit (ssthresh) if it has been updated 1162 * already or if a pipesize was specified & the threshhold 1163 * got below half the pipesize. I.e., wait for bad news 1164 * before we start updating, then update on both good 1165 * and bad news. 1166 */ 1167 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 1168 (i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) || 1169 i < (rt->rt_rmx.rmx_sendpipe / 2)) { 1170 /* 1171 * convert the limit from user data bytes to 1172 * packets then to packet data bytes. 1173 */ 1174 i = (i + tp->t_segsz / 2) / tp->t_segsz; 1175 if (i < 2) 1176 i = 2; 1177 i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr)); 1178 if (rt->rt_rmx.rmx_ssthresh) 1179 rt->rt_rmx.rmx_ssthresh = 1180 (rt->rt_rmx.rmx_ssthresh + i) / 2; 1181 else 1182 rt->rt_rmx.rmx_ssthresh = i; 1183 } 1184 } 1185 #endif /* RTV_RTT */ 1186 /* free the reassembly queue, if any */ 1187 TCP_REASS_LOCK(tp); 1188 (void) tcp_freeq(tp); 1189 TCP_REASS_UNLOCK(tp); 1190 1191 /* free the SACK holes list. */ 1192 tcp_free_sackholes(tp); 1193 1194 tcp_canceltimers(tp); 1195 TCP_CLEAR_DELACK(tp); 1196 syn_cache_cleanup(tp); 1197 1198 if (tp->t_template) { 1199 m_free(tp->t_template); 1200 tp->t_template = NULL; 1201 } 1202 if (tcp_timers_invoking(tp)) 1203 tp->t_flags |= TF_DEAD; 1204 else 1205 pool_put(&tcpcb_pool, tp); 1206 1207 if (inp) { 1208 inp->inp_ppcb = 0; 1209 soisdisconnected(so); 1210 in_pcbdetach(inp); 1211 } 1212 #ifdef INET6 1213 else if (in6p) { 1214 in6p->in6p_ppcb = 0; 1215 soisdisconnected(so); 1216 in6_pcbdetach(in6p); 1217 } 1218 #endif 1219 tcpstat.tcps_closed++; 1220 return ((struct tcpcb *)0); 1221 } 1222 1223 int 1224 tcp_freeq(tp) 1225 struct tcpcb *tp; 1226 { 1227 struct ipqent *qe; 1228 int rv = 0; 1229 #ifdef TCPREASS_DEBUG 1230 int i = 0; 1231 #endif 1232 1233 TCP_REASS_LOCK_CHECK(tp); 1234 1235 while ((qe = TAILQ_FIRST(&tp->segq)) != NULL) { 1236 #ifdef TCPREASS_DEBUG 1237 printf("tcp_freeq[%p,%d]: %u:%u(%u) 0x%02x\n", 1238 tp, i++, qe->ipqe_seq, qe->ipqe_seq + qe->ipqe_len, 1239 qe->ipqe_len, qe->ipqe_flags & (TH_SYN|TH_FIN|TH_RST)); 1240 #endif 1241 TAILQ_REMOVE(&tp->segq, qe, ipqe_q); 1242 TAILQ_REMOVE(&tp->timeq, qe, ipqe_timeq); 1243 m_freem(qe->ipqe_m); 1244 tcpipqent_free(qe); 1245 rv = 1; 1246 } 1247 tp->t_segqlen = 0; 1248 KASSERT(TAILQ_EMPTY(&tp->timeq)); 1249 return (rv); 1250 } 1251 1252 /* 1253 * Protocol drain routine. Called when memory is in short supply. 1254 */ 1255 void 1256 tcp_drain(void) 1257 { 1258 struct inpcb_hdr *inph; 1259 struct tcpcb *tp; 1260 1261 /* 1262 * Free the sequence queue of all TCP connections. 1263 */ 1264 CIRCLEQ_FOREACH(inph, &tcbtable.inpt_queue, inph_queue) { 1265 switch (inph->inph_af) { 1266 case AF_INET: 1267 tp = intotcpcb((struct inpcb *)inph); 1268 break; 1269 #ifdef INET6 1270 case AF_INET6: 1271 tp = in6totcpcb((struct in6pcb *)inph); 1272 break; 1273 #endif 1274 default: 1275 tp = NULL; 1276 break; 1277 } 1278 if (tp != NULL) { 1279 /* 1280 * We may be called from a device's interrupt 1281 * context. If the tcpcb is already busy, 1282 * just bail out now. 1283 */ 1284 if (tcp_reass_lock_try(tp) == 0) 1285 continue; 1286 if (tcp_freeq(tp)) 1287 tcpstat.tcps_connsdrained++; 1288 TCP_REASS_UNLOCK(tp); 1289 } 1290 } 1291 } 1292 1293 /* 1294 * Notify a tcp user of an asynchronous error; 1295 * store error as soft error, but wake up user 1296 * (for now, won't do anything until can select for soft error). 1297 */ 1298 void 1299 tcp_notify(struct inpcb *inp, int error) 1300 { 1301 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 1302 struct socket *so = inp->inp_socket; 1303 1304 /* 1305 * Ignore some errors if we are hooked up. 1306 * If connection hasn't completed, has retransmitted several times, 1307 * and receives a second error, give up now. This is better 1308 * than waiting a long time to establish a connection that 1309 * can never complete. 1310 */ 1311 if (tp->t_state == TCPS_ESTABLISHED && 1312 (error == EHOSTUNREACH || error == ENETUNREACH || 1313 error == EHOSTDOWN)) { 1314 return; 1315 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1316 tp->t_rxtshift > 3 && tp->t_softerror) 1317 so->so_error = error; 1318 else 1319 tp->t_softerror = error; 1320 wakeup((caddr_t) &so->so_timeo); 1321 sorwakeup(so); 1322 sowwakeup(so); 1323 } 1324 1325 #ifdef INET6 1326 void 1327 tcp6_notify(struct in6pcb *in6p, int error) 1328 { 1329 struct tcpcb *tp = (struct tcpcb *)in6p->in6p_ppcb; 1330 struct socket *so = in6p->in6p_socket; 1331 1332 /* 1333 * Ignore some errors if we are hooked up. 1334 * If connection hasn't completed, has retransmitted several times, 1335 * and receives a second error, give up now. This is better 1336 * than waiting a long time to establish a connection that 1337 * can never complete. 1338 */ 1339 if (tp->t_state == TCPS_ESTABLISHED && 1340 (error == EHOSTUNREACH || error == ENETUNREACH || 1341 error == EHOSTDOWN)) { 1342 return; 1343 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1344 tp->t_rxtshift > 3 && tp->t_softerror) 1345 so->so_error = error; 1346 else 1347 tp->t_softerror = error; 1348 wakeup((caddr_t) &so->so_timeo); 1349 sorwakeup(so); 1350 sowwakeup(so); 1351 } 1352 #endif 1353 1354 #ifdef INET6 1355 void 1356 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1357 { 1358 struct tcphdr th; 1359 void (*notify)(struct in6pcb *, int) = tcp6_notify; 1360 int nmatch; 1361 struct ip6_hdr *ip6; 1362 const struct sockaddr_in6 *sa6_src = NULL; 1363 struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)sa; 1364 struct mbuf *m; 1365 int off; 1366 1367 if (sa->sa_family != AF_INET6 || 1368 sa->sa_len != sizeof(struct sockaddr_in6)) 1369 return; 1370 if ((unsigned)cmd >= PRC_NCMDS) 1371 return; 1372 else if (cmd == PRC_QUENCH) { 1373 /* 1374 * Don't honor ICMP Source Quench messages meant for 1375 * TCP connections. 1376 */ 1377 return; 1378 } else if (PRC_IS_REDIRECT(cmd)) 1379 notify = in6_rtchange, d = NULL; 1380 else if (cmd == PRC_MSGSIZE) 1381 ; /* special code is present, see below */ 1382 else if (cmd == PRC_HOSTDEAD) 1383 d = NULL; 1384 else if (inet6ctlerrmap[cmd] == 0) 1385 return; 1386 1387 /* if the parameter is from icmp6, decode it. */ 1388 if (d != NULL) { 1389 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 1390 m = ip6cp->ip6c_m; 1391 ip6 = ip6cp->ip6c_ip6; 1392 off = ip6cp->ip6c_off; 1393 sa6_src = ip6cp->ip6c_src; 1394 } else { 1395 m = NULL; 1396 ip6 = NULL; 1397 sa6_src = &sa6_any; 1398 off = 0; 1399 } 1400 1401 if (ip6) { 1402 /* 1403 * XXX: We assume that when ip6 is non NULL, 1404 * M and OFF are valid. 1405 */ 1406 1407 /* check if we can safely examine src and dst ports */ 1408 if (m->m_pkthdr.len < off + sizeof(th)) { 1409 if (cmd == PRC_MSGSIZE) 1410 icmp6_mtudisc_update((struct ip6ctlparam *)d, 0); 1411 return; 1412 } 1413 1414 bzero(&th, sizeof(th)); 1415 m_copydata(m, off, sizeof(th), (caddr_t)&th); 1416 1417 if (cmd == PRC_MSGSIZE) { 1418 int valid = 0; 1419 1420 /* 1421 * Check to see if we have a valid TCP connection 1422 * corresponding to the address in the ICMPv6 message 1423 * payload. 1424 */ 1425 if (in6_pcblookup_connect(&tcbtable, &sa6->sin6_addr, 1426 th.th_dport, (const struct in6_addr *)&sa6_src->sin6_addr, 1427 th.th_sport, 0)) 1428 valid++; 1429 1430 /* 1431 * Depending on the value of "valid" and routing table 1432 * size (mtudisc_{hi,lo}wat), we will: 1433 * - recalcurate the new MTU and create the 1434 * corresponding routing entry, or 1435 * - ignore the MTU change notification. 1436 */ 1437 icmp6_mtudisc_update((struct ip6ctlparam *)d, valid); 1438 1439 /* 1440 * no need to call in6_pcbnotify, it should have been 1441 * called via callback if necessary 1442 */ 1443 return; 1444 } 1445 1446 nmatch = in6_pcbnotify(&tcbtable, sa, th.th_dport, 1447 (const struct sockaddr *)sa6_src, th.th_sport, cmd, NULL, notify); 1448 if (nmatch == 0 && syn_cache_count && 1449 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 1450 inet6ctlerrmap[cmd] == ENETUNREACH || 1451 inet6ctlerrmap[cmd] == EHOSTDOWN)) 1452 syn_cache_unreach((const struct sockaddr *)sa6_src, 1453 sa, &th); 1454 } else { 1455 (void) in6_pcbnotify(&tcbtable, sa, 0, 1456 (const struct sockaddr *)sa6_src, 0, cmd, NULL, notify); 1457 } 1458 } 1459 #endif 1460 1461 #ifdef INET 1462 /* assumes that ip header and tcp header are contiguous on mbuf */ 1463 void * 1464 tcp_ctlinput(int cmd, struct sockaddr *sa, void *v) 1465 { 1466 struct ip *ip = v; 1467 struct tcphdr *th; 1468 struct icmp *icp; 1469 extern const int inetctlerrmap[]; 1470 void (*notify)(struct inpcb *, int) = tcp_notify; 1471 int errno; 1472 int nmatch; 1473 struct tcpcb *tp; 1474 u_int mtu; 1475 tcp_seq seq; 1476 struct inpcb *inp; 1477 #ifdef INET6 1478 struct in6pcb *in6p; 1479 struct in6_addr src6, dst6; 1480 #endif 1481 1482 if (sa->sa_family != AF_INET || 1483 sa->sa_len != sizeof(struct sockaddr_in)) 1484 return NULL; 1485 if ((unsigned)cmd >= PRC_NCMDS) 1486 return NULL; 1487 errno = inetctlerrmap[cmd]; 1488 if (cmd == PRC_QUENCH) 1489 /* 1490 * Don't honor ICMP Source Quench messages meant for 1491 * TCP connections. 1492 */ 1493 return NULL; 1494 else if (PRC_IS_REDIRECT(cmd)) 1495 notify = in_rtchange, ip = 0; 1496 else if (cmd == PRC_MSGSIZE && ip && ip->ip_v == 4) { 1497 /* 1498 * Check to see if we have a valid TCP connection 1499 * corresponding to the address in the ICMP message 1500 * payload. 1501 * 1502 * Boundary check is made in icmp_input(), with ICMP_ADVLENMIN. 1503 */ 1504 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1505 #ifdef INET6 1506 memset(&src6, 0, sizeof(src6)); 1507 memset(&dst6, 0, sizeof(dst6)); 1508 src6.s6_addr16[5] = dst6.s6_addr16[5] = 0xffff; 1509 memcpy(&src6.s6_addr32[3], &ip->ip_src, sizeof(struct in_addr)); 1510 memcpy(&dst6.s6_addr32[3], &ip->ip_dst, sizeof(struct in_addr)); 1511 #endif 1512 if ((inp = in_pcblookup_connect(&tcbtable, ip->ip_dst, 1513 th->th_dport, ip->ip_src, th->th_sport)) != NULL) 1514 in6p = NULL; 1515 #ifdef INET6 1516 else if ((in6p = in6_pcblookup_connect(&tcbtable, &dst6, 1517 th->th_dport, &src6, th->th_sport, 0)) != NULL) 1518 ; 1519 #endif 1520 else 1521 return NULL; 1522 1523 /* 1524 * Now that we've validated that we are actually communicating 1525 * with the host indicated in the ICMP message, locate the 1526 * ICMP header, recalculate the new MTU, and create the 1527 * corresponding routing entry. 1528 */ 1529 icp = (struct icmp *)((caddr_t)ip - 1530 offsetof(struct icmp, icmp_ip)); 1531 if (inp) { 1532 if ((tp = intotcpcb(inp)) == NULL) 1533 return NULL; 1534 } 1535 #ifdef INET6 1536 else if (in6p) { 1537 if ((tp = in6totcpcb(in6p)) == NULL) 1538 return NULL; 1539 } 1540 #endif 1541 else 1542 return NULL; 1543 seq = ntohl(th->th_seq); 1544 if (SEQ_LT(seq, tp->snd_una) || SEQ_GT(seq, tp->snd_max)) 1545 return NULL; 1546 /* 1547 * If the ICMP message advertises a Next-Hop MTU 1548 * equal or larger than the maximum packet size we have 1549 * ever sent, drop the message. 1550 */ 1551 mtu = (u_int)ntohs(icp->icmp_nextmtu); 1552 if (mtu >= tp->t_pmtud_mtu_sent) 1553 return NULL; 1554 if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) { 1555 /* 1556 * Calculate new MTU, and create corresponding 1557 * route (traditional PMTUD). 1558 */ 1559 tp->t_flags &= ~TF_PMTUD_PEND; 1560 icmp_mtudisc(icp, ip->ip_dst); 1561 } else { 1562 /* 1563 * Record the information got in the ICMP 1564 * message; act on it later. 1565 * If we had already recorded an ICMP message, 1566 * replace the old one only if the new message 1567 * refers to an older TCP segment 1568 */ 1569 if (tp->t_flags & TF_PMTUD_PEND) { 1570 if (SEQ_LT(tp->t_pmtud_th_seq, seq)) 1571 return NULL; 1572 } else 1573 tp->t_flags |= TF_PMTUD_PEND; 1574 tp->t_pmtud_th_seq = seq; 1575 tp->t_pmtud_nextmtu = icp->icmp_nextmtu; 1576 tp->t_pmtud_ip_len = icp->icmp_ip.ip_len; 1577 tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl; 1578 } 1579 return NULL; 1580 } else if (cmd == PRC_HOSTDEAD) 1581 ip = 0; 1582 else if (errno == 0) 1583 return NULL; 1584 if (ip && ip->ip_v == 4 && sa->sa_family == AF_INET) { 1585 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 1586 nmatch = in_pcbnotify(&tcbtable, satosin(sa)->sin_addr, 1587 th->th_dport, ip->ip_src, th->th_sport, errno, notify); 1588 if (nmatch == 0 && syn_cache_count && 1589 (inetctlerrmap[cmd] == EHOSTUNREACH || 1590 inetctlerrmap[cmd] == ENETUNREACH || 1591 inetctlerrmap[cmd] == EHOSTDOWN)) { 1592 struct sockaddr_in sin; 1593 bzero(&sin, sizeof(sin)); 1594 sin.sin_len = sizeof(sin); 1595 sin.sin_family = AF_INET; 1596 sin.sin_port = th->th_sport; 1597 sin.sin_addr = ip->ip_src; 1598 syn_cache_unreach((struct sockaddr *)&sin, sa, th); 1599 } 1600 1601 /* XXX mapped address case */ 1602 } else 1603 in_pcbnotifyall(&tcbtable, satosin(sa)->sin_addr, errno, 1604 notify); 1605 return NULL; 1606 } 1607 1608 /* 1609 * When a source quench is received, we are being notified of congestion. 1610 * Close the congestion window down to the Loss Window (one segment). 1611 * We will gradually open it again as we proceed. 1612 */ 1613 void 1614 tcp_quench(struct inpcb *inp, int errno) 1615 { 1616 struct tcpcb *tp = intotcpcb(inp); 1617 1618 if (tp) 1619 tp->snd_cwnd = tp->t_segsz; 1620 } 1621 #endif 1622 1623 #ifdef INET6 1624 void 1625 tcp6_quench(struct in6pcb *in6p, int errno) 1626 { 1627 struct tcpcb *tp = in6totcpcb(in6p); 1628 1629 if (tp) 1630 tp->snd_cwnd = tp->t_segsz; 1631 } 1632 #endif 1633 1634 #ifdef INET 1635 /* 1636 * Path MTU Discovery handlers. 1637 */ 1638 void 1639 tcp_mtudisc_callback(struct in_addr faddr) 1640 { 1641 #ifdef INET6 1642 struct in6_addr in6; 1643 #endif 1644 1645 in_pcbnotifyall(&tcbtable, faddr, EMSGSIZE, tcp_mtudisc); 1646 #ifdef INET6 1647 memset(&in6, 0, sizeof(in6)); 1648 in6.s6_addr16[5] = 0xffff; 1649 memcpy(&in6.s6_addr32[3], &faddr, sizeof(struct in_addr)); 1650 tcp6_mtudisc_callback(&in6); 1651 #endif 1652 } 1653 1654 /* 1655 * On receipt of path MTU corrections, flush old route and replace it 1656 * with the new one. Retransmit all unacknowledged packets, to ensure 1657 * that all packets will be received. 1658 */ 1659 void 1660 tcp_mtudisc(struct inpcb *inp, int errno) 1661 { 1662 struct tcpcb *tp = intotcpcb(inp); 1663 struct rtentry *rt = in_pcbrtentry(inp); 1664 1665 if (tp != 0) { 1666 if (rt != 0) { 1667 /* 1668 * If this was not a host route, remove and realloc. 1669 */ 1670 if ((rt->rt_flags & RTF_HOST) == 0) { 1671 in_rtchange(inp, errno); 1672 if ((rt = in_pcbrtentry(inp)) == 0) 1673 return; 1674 } 1675 1676 /* 1677 * Slow start out of the error condition. We 1678 * use the MTU because we know it's smaller 1679 * than the previously transmitted segment. 1680 * 1681 * Note: This is more conservative than the 1682 * suggestion in draft-floyd-incr-init-win-03. 1683 */ 1684 if (rt->rt_rmx.rmx_mtu != 0) 1685 tp->snd_cwnd = 1686 TCP_INITIAL_WINDOW(tcp_init_win, 1687 rt->rt_rmx.rmx_mtu); 1688 } 1689 1690 /* 1691 * Resend unacknowledged packets. 1692 */ 1693 tp->snd_nxt = tp->snd_una; 1694 tcp_output(tp); 1695 } 1696 } 1697 #endif 1698 1699 #ifdef INET6 1700 /* 1701 * Path MTU Discovery handlers. 1702 */ 1703 void 1704 tcp6_mtudisc_callback(struct in6_addr *faddr) 1705 { 1706 struct sockaddr_in6 sin6; 1707 1708 bzero(&sin6, sizeof(sin6)); 1709 sin6.sin6_family = AF_INET6; 1710 sin6.sin6_len = sizeof(struct sockaddr_in6); 1711 sin6.sin6_addr = *faddr; 1712 (void) in6_pcbnotify(&tcbtable, (struct sockaddr *)&sin6, 0, 1713 (const struct sockaddr *)&sa6_any, 0, PRC_MSGSIZE, NULL, tcp6_mtudisc); 1714 } 1715 1716 void 1717 tcp6_mtudisc(struct in6pcb *in6p, int errno) 1718 { 1719 struct tcpcb *tp = in6totcpcb(in6p); 1720 struct rtentry *rt = in6_pcbrtentry(in6p); 1721 1722 if (tp != 0) { 1723 if (rt != 0) { 1724 /* 1725 * If this was not a host route, remove and realloc. 1726 */ 1727 if ((rt->rt_flags & RTF_HOST) == 0) { 1728 in6_rtchange(in6p, errno); 1729 if ((rt = in6_pcbrtentry(in6p)) == 0) 1730 return; 1731 } 1732 1733 /* 1734 * Slow start out of the error condition. We 1735 * use the MTU because we know it's smaller 1736 * than the previously transmitted segment. 1737 * 1738 * Note: This is more conservative than the 1739 * suggestion in draft-floyd-incr-init-win-03. 1740 */ 1741 if (rt->rt_rmx.rmx_mtu != 0) 1742 tp->snd_cwnd = 1743 TCP_INITIAL_WINDOW(tcp_init_win, 1744 rt->rt_rmx.rmx_mtu); 1745 } 1746 1747 /* 1748 * Resend unacknowledged packets. 1749 */ 1750 tp->snd_nxt = tp->snd_una; 1751 tcp_output(tp); 1752 } 1753 } 1754 #endif /* INET6 */ 1755 1756 /* 1757 * Compute the MSS to advertise to the peer. Called only during 1758 * the 3-way handshake. If we are the server (peer initiated 1759 * connection), we are called with a pointer to the interface 1760 * on which the SYN packet arrived. If we are the client (we 1761 * initiated connection), we are called with a pointer to the 1762 * interface out which this connection should go. 1763 * 1764 * NOTE: Do not subtract IP option/extension header size nor IPsec 1765 * header size from MSS advertisement. MSS option must hold the maximum 1766 * segment size we can accept, so it must always be: 1767 * max(if mtu) - ip header - tcp header 1768 */ 1769 u_long 1770 tcp_mss_to_advertise(const struct ifnet *ifp, int af) 1771 { 1772 extern u_long in_maxmtu; 1773 u_long mss = 0; 1774 u_long hdrsiz; 1775 1776 /* 1777 * In order to avoid defeating path MTU discovery on the peer, 1778 * we advertise the max MTU of all attached networks as our MSS, 1779 * per RFC 1191, section 3.1. 1780 * 1781 * We provide the option to advertise just the MTU of 1782 * the interface on which we hope this connection will 1783 * be receiving. If we are responding to a SYN, we 1784 * will have a pretty good idea about this, but when 1785 * initiating a connection there is a bit more doubt. 1786 * 1787 * We also need to ensure that loopback has a large enough 1788 * MSS, as the loopback MTU is never included in in_maxmtu. 1789 */ 1790 1791 if (ifp != NULL) 1792 switch (af) { 1793 case AF_INET: 1794 mss = ifp->if_mtu; 1795 break; 1796 #ifdef INET6 1797 case AF_INET6: 1798 mss = IN6_LINKMTU(ifp); 1799 break; 1800 #endif 1801 } 1802 1803 if (tcp_mss_ifmtu == 0) 1804 switch (af) { 1805 case AF_INET: 1806 mss = max(in_maxmtu, mss); 1807 break; 1808 #ifdef INET6 1809 case AF_INET6: 1810 mss = max(in6_maxmtu, mss); 1811 break; 1812 #endif 1813 } 1814 1815 switch (af) { 1816 case AF_INET: 1817 hdrsiz = sizeof(struct ip); 1818 break; 1819 #ifdef INET6 1820 case AF_INET6: 1821 hdrsiz = sizeof(struct ip6_hdr); 1822 break; 1823 #endif 1824 default: 1825 hdrsiz = 0; 1826 break; 1827 } 1828 hdrsiz += sizeof(struct tcphdr); 1829 if (mss > hdrsiz) 1830 mss -= hdrsiz; 1831 1832 mss = max(tcp_mssdflt, mss); 1833 return (mss); 1834 } 1835 1836 /* 1837 * Set connection variables based on the peer's advertised MSS. 1838 * We are passed the TCPCB for the actual connection. If we 1839 * are the server, we are called by the compressed state engine 1840 * when the 3-way handshake is complete. If we are the client, 1841 * we are called when we receive the SYN,ACK from the server. 1842 * 1843 * NOTE: Our advertised MSS value must be initialized in the TCPCB 1844 * before this routine is called! 1845 */ 1846 void 1847 tcp_mss_from_peer(struct tcpcb *tp, int offer) 1848 { 1849 struct socket *so; 1850 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1851 struct rtentry *rt; 1852 #endif 1853 u_long bufsize; 1854 int mss; 1855 1856 #ifdef DIAGNOSTIC 1857 if (tp->t_inpcb && tp->t_in6pcb) 1858 panic("tcp_mss_from_peer: both t_inpcb and t_in6pcb are set"); 1859 #endif 1860 so = NULL; 1861 rt = NULL; 1862 #ifdef INET 1863 if (tp->t_inpcb) { 1864 so = tp->t_inpcb->inp_socket; 1865 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1866 rt = in_pcbrtentry(tp->t_inpcb); 1867 #endif 1868 } 1869 #endif 1870 #ifdef INET6 1871 if (tp->t_in6pcb) { 1872 so = tp->t_in6pcb->in6p_socket; 1873 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1874 rt = in6_pcbrtentry(tp->t_in6pcb); 1875 #endif 1876 } 1877 #endif 1878 1879 /* 1880 * As per RFC1122, use the default MSS value, unless they 1881 * sent us an offer. Do not accept offers less than 256 bytes. 1882 */ 1883 mss = tcp_mssdflt; 1884 if (offer) 1885 mss = offer; 1886 mss = max(mss, 256); /* sanity */ 1887 tp->t_peermss = mss; 1888 mss -= tcp_optlen(tp); 1889 #ifdef INET 1890 if (tp->t_inpcb) 1891 mss -= ip_optlen(tp->t_inpcb); 1892 #endif 1893 #ifdef INET6 1894 if (tp->t_in6pcb) 1895 mss -= ip6_optlen(tp->t_in6pcb); 1896 #endif 1897 1898 /* 1899 * If there's a pipesize, change the socket buffer to that size. 1900 * Make the socket buffer an integral number of MSS units. If 1901 * the MSS is larger than the socket buffer, artificially decrease 1902 * the MSS. 1903 */ 1904 #ifdef RTV_SPIPE 1905 if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0) 1906 bufsize = rt->rt_rmx.rmx_sendpipe; 1907 else 1908 #endif 1909 bufsize = so->so_snd.sb_hiwat; 1910 if (bufsize < mss) 1911 mss = bufsize; 1912 else { 1913 bufsize = roundup(bufsize, mss); 1914 if (bufsize > sb_max) 1915 bufsize = sb_max; 1916 (void) sbreserve(&so->so_snd, bufsize, so); 1917 } 1918 tp->t_segsz = mss; 1919 1920 #ifdef RTV_SSTHRESH 1921 if (rt != NULL && rt->rt_rmx.rmx_ssthresh) { 1922 /* 1923 * There's some sort of gateway or interface buffer 1924 * limit on the path. Use this to set the slow 1925 * start threshold, but set the threshold to no less 1926 * than 2 * MSS. 1927 */ 1928 tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh); 1929 } 1930 #endif 1931 } 1932 1933 /* 1934 * Processing necessary when a TCP connection is established. 1935 */ 1936 void 1937 tcp_established(struct tcpcb *tp) 1938 { 1939 struct socket *so; 1940 #ifdef RTV_RPIPE 1941 struct rtentry *rt; 1942 #endif 1943 u_long bufsize; 1944 1945 #ifdef DIAGNOSTIC 1946 if (tp->t_inpcb && tp->t_in6pcb) 1947 panic("tcp_established: both t_inpcb and t_in6pcb are set"); 1948 #endif 1949 so = NULL; 1950 rt = NULL; 1951 #ifdef INET 1952 if (tp->t_inpcb) { 1953 so = tp->t_inpcb->inp_socket; 1954 #if defined(RTV_RPIPE) 1955 rt = in_pcbrtentry(tp->t_inpcb); 1956 #endif 1957 } 1958 #endif 1959 #ifdef INET6 1960 if (tp->t_in6pcb) { 1961 so = tp->t_in6pcb->in6p_socket; 1962 #if defined(RTV_RPIPE) 1963 rt = in6_pcbrtentry(tp->t_in6pcb); 1964 #endif 1965 } 1966 #endif 1967 1968 tp->t_state = TCPS_ESTABLISHED; 1969 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle); 1970 1971 #ifdef RTV_RPIPE 1972 if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0) 1973 bufsize = rt->rt_rmx.rmx_recvpipe; 1974 else 1975 #endif 1976 bufsize = so->so_rcv.sb_hiwat; 1977 if (bufsize > tp->t_ourmss) { 1978 bufsize = roundup(bufsize, tp->t_ourmss); 1979 if (bufsize > sb_max) 1980 bufsize = sb_max; 1981 (void) sbreserve(&so->so_rcv, bufsize, so); 1982 } 1983 } 1984 1985 /* 1986 * Check if there's an initial rtt or rttvar. Convert from the 1987 * route-table units to scaled multiples of the slow timeout timer. 1988 * Called only during the 3-way handshake. 1989 */ 1990 void 1991 tcp_rmx_rtt(struct tcpcb *tp) 1992 { 1993 #ifdef RTV_RTT 1994 struct rtentry *rt = NULL; 1995 int rtt; 1996 1997 #ifdef DIAGNOSTIC 1998 if (tp->t_inpcb && tp->t_in6pcb) 1999 panic("tcp_rmx_rtt: both t_inpcb and t_in6pcb are set"); 2000 #endif 2001 #ifdef INET 2002 if (tp->t_inpcb) 2003 rt = in_pcbrtentry(tp->t_inpcb); 2004 #endif 2005 #ifdef INET6 2006 if (tp->t_in6pcb) 2007 rt = in6_pcbrtentry(tp->t_in6pcb); 2008 #endif 2009 if (rt == NULL) 2010 return; 2011 2012 if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) { 2013 /* 2014 * XXX The lock bit for MTU indicates that the value 2015 * is also a minimum value; this is subject to time. 2016 */ 2017 if (rt->rt_rmx.rmx_locks & RTV_RTT) 2018 TCPT_RANGESET(tp->t_rttmin, 2019 rtt / (RTM_RTTUNIT / PR_SLOWHZ), 2020 TCPTV_MIN, TCPTV_REXMTMAX); 2021 tp->t_srtt = rtt / 2022 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 2023 if (rt->rt_rmx.rmx_rttvar) { 2024 tp->t_rttvar = rt->rt_rmx.rmx_rttvar / 2025 ((RTM_RTTUNIT / PR_SLOWHZ) >> 2026 (TCP_RTTVAR_SHIFT + 2)); 2027 } else { 2028 /* Default variation is +- 1 rtt */ 2029 tp->t_rttvar = 2030 tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT); 2031 } 2032 TCPT_RANGESET(tp->t_rxtcur, 2033 ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2), 2034 tp->t_rttmin, TCPTV_REXMTMAX); 2035 } 2036 #endif 2037 } 2038 2039 tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */ 2040 #if NRND > 0 2041 u_int8_t tcp_iss_secret[16]; /* 128 bits; should be plenty */ 2042 #endif 2043 2044 /* 2045 * Get a new sequence value given a tcp control block 2046 */ 2047 tcp_seq 2048 tcp_new_iss(struct tcpcb *tp, tcp_seq addin) 2049 { 2050 2051 #ifdef INET 2052 if (tp->t_inpcb != NULL) { 2053 return (tcp_new_iss1(&tp->t_inpcb->inp_laddr, 2054 &tp->t_inpcb->inp_faddr, tp->t_inpcb->inp_lport, 2055 tp->t_inpcb->inp_fport, sizeof(tp->t_inpcb->inp_laddr), 2056 addin)); 2057 } 2058 #endif 2059 #ifdef INET6 2060 if (tp->t_in6pcb != NULL) { 2061 return (tcp_new_iss1(&tp->t_in6pcb->in6p_laddr, 2062 &tp->t_in6pcb->in6p_faddr, tp->t_in6pcb->in6p_lport, 2063 tp->t_in6pcb->in6p_fport, sizeof(tp->t_in6pcb->in6p_laddr), 2064 addin)); 2065 } 2066 #endif 2067 /* Not possible. */ 2068 panic("tcp_new_iss"); 2069 } 2070 2071 /* 2072 * This routine actually generates a new TCP initial sequence number. 2073 */ 2074 tcp_seq 2075 tcp_new_iss1(void *laddr, void *faddr, u_int16_t lport, u_int16_t fport, 2076 size_t addrsz, tcp_seq addin) 2077 { 2078 tcp_seq tcp_iss; 2079 2080 #if NRND > 0 2081 static int beenhere; 2082 2083 /* 2084 * If we haven't been here before, initialize our cryptographic 2085 * hash secret. 2086 */ 2087 if (beenhere == 0) { 2088 rnd_extract_data(tcp_iss_secret, sizeof(tcp_iss_secret), 2089 RND_EXTRACT_ANY); 2090 beenhere = 1; 2091 } 2092 2093 if (tcp_do_rfc1948) { 2094 MD5_CTX ctx; 2095 u_int8_t hash[16]; /* XXX MD5 knowledge */ 2096 2097 /* 2098 * Compute the base value of the ISS. It is a hash 2099 * of (saddr, sport, daddr, dport, secret). 2100 */ 2101 MD5Init(&ctx); 2102 2103 MD5Update(&ctx, (u_char *) laddr, addrsz); 2104 MD5Update(&ctx, (u_char *) &lport, sizeof(lport)); 2105 2106 MD5Update(&ctx, (u_char *) faddr, addrsz); 2107 MD5Update(&ctx, (u_char *) &fport, sizeof(fport)); 2108 2109 MD5Update(&ctx, tcp_iss_secret, sizeof(tcp_iss_secret)); 2110 2111 MD5Final(hash, &ctx); 2112 2113 memcpy(&tcp_iss, hash, sizeof(tcp_iss)); 2114 2115 /* 2116 * Now increment our "timer", and add it in to 2117 * the computed value. 2118 * 2119 * XXX Use `addin'? 2120 * XXX TCP_ISSINCR too large to use? 2121 */ 2122 tcp_iss_seq += TCP_ISSINCR; 2123 #ifdef TCPISS_DEBUG 2124 printf("ISS hash 0x%08x, ", tcp_iss); 2125 #endif 2126 tcp_iss += tcp_iss_seq + addin; 2127 #ifdef TCPISS_DEBUG 2128 printf("new ISS 0x%08x\n", tcp_iss); 2129 #endif 2130 } else 2131 #endif /* NRND > 0 */ 2132 { 2133 /* 2134 * Randomize. 2135 */ 2136 #if NRND > 0 2137 rnd_extract_data(&tcp_iss, sizeof(tcp_iss), RND_EXTRACT_ANY); 2138 #else 2139 tcp_iss = arc4random(); 2140 #endif 2141 2142 /* 2143 * If we were asked to add some amount to a known value, 2144 * we will take a random value obtained above, mask off 2145 * the upper bits, and add in the known value. We also 2146 * add in a constant to ensure that we are at least a 2147 * certain distance from the original value. 2148 * 2149 * This is used when an old connection is in timed wait 2150 * and we have a new one coming in, for instance. 2151 */ 2152 if (addin != 0) { 2153 #ifdef TCPISS_DEBUG 2154 printf("Random %08x, ", tcp_iss); 2155 #endif 2156 tcp_iss &= TCP_ISS_RANDOM_MASK; 2157 tcp_iss += addin + TCP_ISSINCR; 2158 #ifdef TCPISS_DEBUG 2159 printf("Old ISS %08x, ISS %08x\n", addin, tcp_iss); 2160 #endif 2161 } else { 2162 tcp_iss &= TCP_ISS_RANDOM_MASK; 2163 tcp_iss += tcp_iss_seq; 2164 tcp_iss_seq += TCP_ISSINCR; 2165 #ifdef TCPISS_DEBUG 2166 printf("ISS %08x\n", tcp_iss); 2167 #endif 2168 } 2169 } 2170 2171 if (tcp_compat_42) { 2172 /* 2173 * Limit it to the positive range for really old TCP 2174 * implementations. 2175 * Just AND off the top bit instead of checking if 2176 * is set first - saves a branch 50% of the time. 2177 */ 2178 tcp_iss &= 0x7fffffff; /* XXX */ 2179 } 2180 2181 return (tcp_iss); 2182 } 2183 2184 #if defined(IPSEC) || defined(FAST_IPSEC) 2185 /* compute ESP/AH header size for TCP, including outer IP header. */ 2186 size_t 2187 ipsec4_hdrsiz_tcp(struct tcpcb *tp) 2188 { 2189 struct inpcb *inp; 2190 size_t hdrsiz; 2191 2192 /* XXX mapped addr case (tp->t_in6pcb) */ 2193 if (!tp || !tp->t_template || !(inp = tp->t_inpcb)) 2194 return 0; 2195 switch (tp->t_family) { 2196 case AF_INET: 2197 /* XXX: should use currect direction. */ 2198 hdrsiz = ipsec4_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, inp); 2199 break; 2200 default: 2201 hdrsiz = 0; 2202 break; 2203 } 2204 2205 return hdrsiz; 2206 } 2207 2208 #ifdef INET6 2209 size_t 2210 ipsec6_hdrsiz_tcp(struct tcpcb *tp) 2211 { 2212 struct in6pcb *in6p; 2213 size_t hdrsiz; 2214 2215 if (!tp || !tp->t_template || !(in6p = tp->t_in6pcb)) 2216 return 0; 2217 switch (tp->t_family) { 2218 case AF_INET6: 2219 /* XXX: should use currect direction. */ 2220 hdrsiz = ipsec6_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, in6p); 2221 break; 2222 case AF_INET: 2223 /* mapped address case - tricky */ 2224 default: 2225 hdrsiz = 0; 2226 break; 2227 } 2228 2229 return hdrsiz; 2230 } 2231 #endif 2232 #endif /*IPSEC*/ 2233 2234 /* 2235 * Determine the length of the TCP options for this connection. 2236 * 2237 * XXX: What do we do for SACK, when we add that? Just reserve 2238 * all of the space? Otherwise we can't exactly be incrementing 2239 * cwnd by an amount that varies depending on the amount we last 2240 * had to SACK! 2241 */ 2242 2243 u_int 2244 tcp_optlen(struct tcpcb *tp) 2245 { 2246 u_int optlen; 2247 2248 optlen = 0; 2249 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 2250 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 2251 optlen += TCPOLEN_TSTAMP_APPA; 2252 2253 #ifdef TCP_SIGNATURE 2254 #if defined(INET6) && defined(FAST_IPSEC) 2255 if (tp->t_family == AF_INET) 2256 #endif 2257 if (tp->t_flags & TF_SIGNATURE) 2258 optlen += TCPOLEN_SIGNATURE + 2; 2259 #endif /* TCP_SIGNATURE */ 2260 2261 return optlen; 2262 } 2263 2264 u_int 2265 tcp_hdrsz(struct tcpcb *tp) 2266 { 2267 u_int hlen; 2268 2269 switch (tp->t_family) { 2270 #ifdef INET6 2271 case AF_INET6: 2272 hlen = sizeof(struct ip6_hdr); 2273 break; 2274 #endif 2275 case AF_INET: 2276 hlen = sizeof(struct ip); 2277 break; 2278 default: 2279 hlen = 0; 2280 break; 2281 } 2282 hlen += sizeof(struct tcphdr); 2283 2284 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 2285 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 2286 hlen += TCPOLEN_TSTAMP_APPA; 2287 #ifdef TCP_SIGNATURE 2288 if (tp->t_flags & TF_SIGNATURE) 2289 hlen += TCPOLEN_SIGLEN; 2290 #endif 2291 return hlen; 2292 } 2293
Indexes created Sun Sep 21 20:09:37 GMT 2025