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sys/netinet/tcp_subr.c
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1 /* $NetBSD: tcp_subr.c,v 1.296 2022/11/04 09:01:53 ozaki-r 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, 2008 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 * 49 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 50 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 51 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 52 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 53 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 54 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 55 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 56 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 57 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 58 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 59 * POSSIBILITY OF SUCH DAMAGE. 60 */ 61 62 /* 63 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 64 * The Regents of the University of California. All rights reserved. 65 * 66 * Redistribution and use in source and binary forms, with or without 67 * modification, are permitted provided that the following conditions 68 * are met: 69 * 1. Redistributions of source code must retain the above copyright 70 * notice, this list of conditions and the following disclaimer. 71 * 2. Redistributions in binary form must reproduce the above copyright 72 * notice, this list of conditions and the following disclaimer in the 73 * documentation and/or other materials provided with the distribution. 74 * 3. Neither the name of the University nor the names of its contributors 75 * may be used to endorse or promote products derived from this software 76 * without specific prior written permission. 77 * 78 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 79 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 80 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 81 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 82 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 83 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 84 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 85 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 86 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 87 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 88 * SUCH DAMAGE. 89 * 90 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 91 */ 92 93 #include <sys/cdefs.h> 94 __KERNEL_RCSID(0, "$NetBSD: tcp_subr.c,v 1.296 2022/11/04 09:01:53 ozaki-r Exp $"); 95 96 #ifdef _KERNEL_OPT 97 #include "opt_inet.h" 98 #include "opt_ipsec.h" 99 #include "opt_inet_csum.h" 100 #include "opt_mbuftrace.h" 101 #endif 102 103 #include <sys/param.h> 104 #include <sys/atomic.h> 105 #include <sys/proc.h> 106 #include <sys/systm.h> 107 #include <sys/mbuf.h> 108 #include <sys/once.h> 109 #include <sys/socket.h> 110 #include <sys/socketvar.h> 111 #include <sys/protosw.h> 112 #include <sys/errno.h> 113 #include <sys/kernel.h> 114 #include <sys/pool.h> 115 #include <sys/md5.h> 116 #include <sys/cprng.h> 117 118 #include <net/route.h> 119 #include <net/if.h> 120 121 #include <netinet/in.h> 122 #include <netinet/in_systm.h> 123 #include <netinet/ip.h> 124 #include <netinet/in_pcb.h> 125 #include <netinet/ip_var.h> 126 #include <netinet/ip_icmp.h> 127 128 #ifdef INET6 129 #include <netinet/ip6.h> 130 #include <netinet6/in6_pcb.h> 131 #include <netinet6/ip6_var.h> 132 #include <netinet6/in6_var.h> 133 #include <netinet6/ip6protosw.h> 134 #include <netinet/icmp6.h> 135 #include <netinet6/nd6.h> 136 #endif 137 138 #include <netinet/tcp.h> 139 #include <netinet/tcp_fsm.h> 140 #include <netinet/tcp_seq.h> 141 #include <netinet/tcp_timer.h> 142 #include <netinet/tcp_var.h> 143 #include <netinet/tcp_vtw.h> 144 #include <netinet/tcp_private.h> 145 #include <netinet/tcp_congctl.h> 146 #include <netinet/tcp_syncache.h> 147 148 #ifdef IPSEC 149 #include <netipsec/ipsec.h> 150 #ifdef INET6 151 #include <netipsec/ipsec6.h> 152 #endif 153 #include <netipsec/key.h> 154 #endif 155 156 157 struct inpcbtable tcbtable; /* head of queue of active tcpcb's */ 158 u_int32_t tcp_now; /* slow ticks, for RFC 1323 timestamps */ 159 160 percpu_t *tcpstat_percpu; 161 162 /* patchable/settable parameters for tcp */ 163 int tcp_mssdflt = TCP_MSS; 164 int tcp_minmss = TCP_MINMSS; 165 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 166 int tcp_do_rfc1323 = 1; /* window scaling / timestamps (obsolete) */ 167 int tcp_do_rfc1948 = 0; /* ISS by cryptographic hash */ 168 int tcp_do_sack = 1; /* selective acknowledgement */ 169 int tcp_do_win_scale = 1; /* RFC1323 window scaling */ 170 int tcp_do_timestamps = 1; /* RFC1323 timestamps */ 171 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ 172 int tcp_do_ecn = 0; /* Explicit Congestion Notification */ 173 #ifndef TCP_INIT_WIN 174 #define TCP_INIT_WIN 4 /* initial slow start window */ 175 #endif 176 #ifndef TCP_INIT_WIN_LOCAL 177 #define TCP_INIT_WIN_LOCAL 4 /* initial slow start window for local nets */ 178 #endif 179 /* 180 * Up to 5 we scale linearly, to reach 3 * 1460; then (iw) * 1460. 181 * This is to simulate current behavior for iw == 4 182 */ 183 int tcp_init_win_max[] = { 184 1 * 1460, 185 1 * 1460, 186 2 * 1460, 187 2 * 1460, 188 3 * 1460, 189 5 * 1460, 190 6 * 1460, 191 7 * 1460, 192 8 * 1460, 193 9 * 1460, 194 10 * 1460 195 }; 196 int tcp_init_win = TCP_INIT_WIN; 197 int tcp_init_win_local = TCP_INIT_WIN_LOCAL; 198 int tcp_mss_ifmtu = 0; 199 int tcp_rst_ppslim = 100; /* 100pps */ 200 int tcp_ackdrop_ppslim = 100; /* 100pps */ 201 int tcp_do_loopback_cksum = 0; 202 int tcp_do_abc = 1; /* RFC3465 Appropriate byte counting. */ 203 int tcp_abc_aggressive = 1; /* 1: L=2*SMSS 0: L=1*SMSS */ 204 int tcp_sack_tp_maxholes = 32; 205 int tcp_sack_globalmaxholes = 1024; 206 int tcp_sack_globalholes = 0; 207 int tcp_ecn_maxretries = 1; 208 int tcp_msl_enable = 1; /* enable TIME_WAIT truncation */ 209 int tcp_msl_loop = PR_SLOWHZ; /* MSL for loopback */ 210 int tcp_msl_local = 5 * PR_SLOWHZ; /* MSL for 'local' */ 211 int tcp_msl_remote = TCPTV_MSL; /* MSL otherwise */ 212 int tcp_msl_remote_threshold = TCPTV_SRTTDFLT; /* RTT threshold */ 213 int tcp_rttlocal = 0; /* Use RTT to decide who's 'local' */ 214 215 int tcp4_vtw_enable = 0; /* 1 to enable */ 216 int tcp6_vtw_enable = 0; /* 1 to enable */ 217 int tcp_vtw_was_enabled = 0; 218 int tcp_vtw_entries = 1 << 4; /* 16 vestigial TIME_WAIT entries */ 219 220 /* tcb hash */ 221 #ifndef TCBHASHSIZE 222 #define TCBHASHSIZE 128 223 #endif 224 int tcbhashsize = TCBHASHSIZE; 225 226 int tcp_freeq(struct tcpcb *); 227 static int tcp_iss_secret_init(void); 228 229 static void tcp_mtudisc_callback(struct in_addr); 230 231 #ifdef INET6 232 static void tcp6_mtudisc(struct inpcb *, int); 233 #endif 234 235 static struct pool tcpcb_pool; 236 237 static int tcp_drainwanted; 238 239 #ifdef TCP_CSUM_COUNTERS 240 #include <sys/device.h> 241 242 struct evcnt tcp_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 243 NULL, "tcp", "hwcsum bad"); 244 struct evcnt tcp_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 245 NULL, "tcp", "hwcsum ok"); 246 struct evcnt tcp_hwcsum_data = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 247 NULL, "tcp", "hwcsum data"); 248 struct evcnt tcp_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 249 NULL, "tcp", "swcsum"); 250 251 EVCNT_ATTACH_STATIC(tcp_hwcsum_bad); 252 EVCNT_ATTACH_STATIC(tcp_hwcsum_ok); 253 EVCNT_ATTACH_STATIC(tcp_hwcsum_data); 254 EVCNT_ATTACH_STATIC(tcp_swcsum); 255 256 #if defined(INET6) 257 struct evcnt tcp6_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 258 NULL, "tcp6", "hwcsum bad"); 259 struct evcnt tcp6_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 260 NULL, "tcp6", "hwcsum ok"); 261 struct evcnt tcp6_hwcsum_data = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 262 NULL, "tcp6", "hwcsum data"); 263 struct evcnt tcp6_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 264 NULL, "tcp6", "swcsum"); 265 266 EVCNT_ATTACH_STATIC(tcp6_hwcsum_bad); 267 EVCNT_ATTACH_STATIC(tcp6_hwcsum_ok); 268 EVCNT_ATTACH_STATIC(tcp6_hwcsum_data); 269 EVCNT_ATTACH_STATIC(tcp6_swcsum); 270 #endif /* defined(INET6) */ 271 #endif /* TCP_CSUM_COUNTERS */ 272 273 274 #ifdef TCP_OUTPUT_COUNTERS 275 #include <sys/device.h> 276 277 struct evcnt tcp_output_bigheader = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 278 NULL, "tcp", "output big header"); 279 struct evcnt tcp_output_predict_hit = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 280 NULL, "tcp", "output predict hit"); 281 struct evcnt tcp_output_predict_miss = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 282 NULL, "tcp", "output predict miss"); 283 struct evcnt tcp_output_copysmall = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 284 NULL, "tcp", "output copy small"); 285 struct evcnt tcp_output_copybig = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 286 NULL, "tcp", "output copy big"); 287 struct evcnt tcp_output_refbig = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 288 NULL, "tcp", "output reference big"); 289 290 EVCNT_ATTACH_STATIC(tcp_output_bigheader); 291 EVCNT_ATTACH_STATIC(tcp_output_predict_hit); 292 EVCNT_ATTACH_STATIC(tcp_output_predict_miss); 293 EVCNT_ATTACH_STATIC(tcp_output_copysmall); 294 EVCNT_ATTACH_STATIC(tcp_output_copybig); 295 EVCNT_ATTACH_STATIC(tcp_output_refbig); 296 297 #endif /* TCP_OUTPUT_COUNTERS */ 298 299 #ifdef TCP_REASS_COUNTERS 300 #include <sys/device.h> 301 302 struct evcnt tcp_reass_ = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 303 NULL, "tcp_reass", "calls"); 304 struct evcnt tcp_reass_empty = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 305 &tcp_reass_, "tcp_reass", "insert into empty queue"); 306 struct evcnt tcp_reass_iteration[8] = { 307 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", ">7 iterations"), 308 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "1 iteration"), 309 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "2 iterations"), 310 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "3 iterations"), 311 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "4 iterations"), 312 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "5 iterations"), 313 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "6 iterations"), 314 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "7 iterations"), 315 }; 316 struct evcnt tcp_reass_prependfirst = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 317 &tcp_reass_, "tcp_reass", "prepend to first"); 318 struct evcnt tcp_reass_prepend = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 319 &tcp_reass_, "tcp_reass", "prepend"); 320 struct evcnt tcp_reass_insert = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 321 &tcp_reass_, "tcp_reass", "insert"); 322 struct evcnt tcp_reass_inserttail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 323 &tcp_reass_, "tcp_reass", "insert at tail"); 324 struct evcnt tcp_reass_append = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 325 &tcp_reass_, "tcp_reass", "append"); 326 struct evcnt tcp_reass_appendtail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 327 &tcp_reass_, "tcp_reass", "append to tail fragment"); 328 struct evcnt tcp_reass_overlaptail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 329 &tcp_reass_, "tcp_reass", "overlap at end"); 330 struct evcnt tcp_reass_overlapfront = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 331 &tcp_reass_, "tcp_reass", "overlap at start"); 332 struct evcnt tcp_reass_segdup = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 333 &tcp_reass_, "tcp_reass", "duplicate segment"); 334 struct evcnt tcp_reass_fragdup = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 335 &tcp_reass_, "tcp_reass", "duplicate fragment"); 336 337 EVCNT_ATTACH_STATIC(tcp_reass_); 338 EVCNT_ATTACH_STATIC(tcp_reass_empty); 339 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 0); 340 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 1); 341 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 2); 342 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 3); 343 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 4); 344 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 5); 345 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 6); 346 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 7); 347 EVCNT_ATTACH_STATIC(tcp_reass_prependfirst); 348 EVCNT_ATTACH_STATIC(tcp_reass_prepend); 349 EVCNT_ATTACH_STATIC(tcp_reass_insert); 350 EVCNT_ATTACH_STATIC(tcp_reass_inserttail); 351 EVCNT_ATTACH_STATIC(tcp_reass_append); 352 EVCNT_ATTACH_STATIC(tcp_reass_appendtail); 353 EVCNT_ATTACH_STATIC(tcp_reass_overlaptail); 354 EVCNT_ATTACH_STATIC(tcp_reass_overlapfront); 355 EVCNT_ATTACH_STATIC(tcp_reass_segdup); 356 EVCNT_ATTACH_STATIC(tcp_reass_fragdup); 357 358 #endif /* TCP_REASS_COUNTERS */ 359 360 #ifdef MBUFTRACE 361 struct mowner tcp_mowner = MOWNER_INIT("tcp", ""); 362 struct mowner tcp_rx_mowner = MOWNER_INIT("tcp", "rx"); 363 struct mowner tcp_tx_mowner = MOWNER_INIT("tcp", "tx"); 364 struct mowner tcp_sock_mowner = MOWNER_INIT("tcp", "sock"); 365 struct mowner tcp_sock_rx_mowner = MOWNER_INIT("tcp", "sock rx"); 366 struct mowner tcp_sock_tx_mowner = MOWNER_INIT("tcp", "sock tx"); 367 #endif 368 369 static int 370 do_tcpinit(void) 371 { 372 373 inpcb_init(&tcbtable, tcbhashsize, tcbhashsize); 374 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl", 375 NULL, IPL_SOFTNET); 376 377 tcp_usrreq_init(); 378 379 /* Initialize timer state. */ 380 tcp_timer_init(); 381 382 /* Initialize the compressed state engine. */ 383 syn_cache_init(); 384 385 /* Initialize the congestion control algorithms. */ 386 tcp_congctl_init(); 387 388 /* Initialize the TCPCB template. */ 389 tcp_tcpcb_template(); 390 391 /* Initialize reassembly queue */ 392 tcpipqent_init(); 393 394 /* SACK */ 395 tcp_sack_init(); 396 397 MOWNER_ATTACH(&tcp_tx_mowner); 398 MOWNER_ATTACH(&tcp_rx_mowner); 399 MOWNER_ATTACH(&tcp_reass_mowner); 400 MOWNER_ATTACH(&tcp_sock_mowner); 401 MOWNER_ATTACH(&tcp_sock_tx_mowner); 402 MOWNER_ATTACH(&tcp_sock_rx_mowner); 403 MOWNER_ATTACH(&tcp_mowner); 404 405 tcpstat_percpu = percpu_alloc(sizeof(uint64_t) * TCP_NSTATS); 406 407 vtw_earlyinit(); 408 409 tcp_slowtimo_init(); 410 411 return 0; 412 } 413 414 void 415 tcp_init_common(unsigned basehlen) 416 { 417 static ONCE_DECL(dotcpinit); 418 unsigned hlen = basehlen + sizeof(struct tcphdr); 419 unsigned oldhlen; 420 421 if (max_linkhdr + hlen > MHLEN) 422 panic("tcp_init"); 423 while ((oldhlen = max_protohdr) < hlen) 424 atomic_cas_uint(&max_protohdr, oldhlen, hlen); 425 426 RUN_ONCE(&dotcpinit, do_tcpinit); 427 } 428 429 /* 430 * Tcp initialization 431 */ 432 void 433 tcp_init(void) 434 { 435 436 icmp_mtudisc_callback_register(tcp_mtudisc_callback); 437 438 tcp_init_common(sizeof(struct ip)); 439 } 440 441 /* 442 * Create template to be used to send tcp packets on a connection. 443 * Call after host entry created, allocates an mbuf and fills 444 * in a skeletal tcp/ip header, minimizing the amount of work 445 * necessary when the connection is used. 446 */ 447 struct mbuf * 448 tcp_template(struct tcpcb *tp) 449 { 450 struct inpcb *inp = tp->t_inpcb; 451 struct tcphdr *n; 452 struct mbuf *m; 453 int hlen; 454 455 switch (tp->t_family) { 456 case AF_INET: 457 hlen = sizeof(struct ip); 458 if (inp->inp_af == AF_INET) 459 break; 460 #ifdef INET6 461 if (inp->inp_af == AF_INET6) { 462 /* mapped addr case */ 463 if (IN6_IS_ADDR_V4MAPPED(&in6p_laddr(inp)) 464 && IN6_IS_ADDR_V4MAPPED(&in6p_faddr(inp))) 465 break; 466 } 467 #endif 468 return NULL; /*EINVAL*/ 469 #ifdef INET6 470 case AF_INET6: 471 hlen = sizeof(struct ip6_hdr); 472 if (inp != NULL) { 473 /* more sainty check? */ 474 break; 475 } 476 return NULL; /*EINVAL*/ 477 #endif 478 default: 479 return NULL; /*EAFNOSUPPORT*/ 480 } 481 482 KASSERT(hlen + sizeof(struct tcphdr) <= MCLBYTES); 483 484 m = tp->t_template; 485 if (m && m->m_len == hlen + sizeof(struct tcphdr)) { 486 ; 487 } else { 488 if (m) 489 m_freem(m); 490 m = tp->t_template = NULL; 491 MGETHDR(m, M_DONTWAIT, MT_HEADER); 492 if (m && hlen + sizeof(struct tcphdr) > MHLEN) { 493 MCLGET(m, M_DONTWAIT); 494 if ((m->m_flags & M_EXT) == 0) { 495 m_free(m); 496 m = NULL; 497 } 498 } 499 if (m == NULL) 500 return NULL; 501 MCLAIM(m, &tcp_mowner); 502 m->m_pkthdr.len = m->m_len = hlen + sizeof(struct tcphdr); 503 } 504 505 memset(mtod(m, void *), 0, m->m_len); 506 507 n = (struct tcphdr *)(mtod(m, char *) + hlen); 508 509 switch (tp->t_family) { 510 case AF_INET: 511 { 512 struct ipovly *ipov; 513 mtod(m, struct ip *)->ip_v = 4; 514 mtod(m, struct ip *)->ip_hl = hlen >> 2; 515 ipov = mtod(m, struct ipovly *); 516 ipov->ih_pr = IPPROTO_TCP; 517 ipov->ih_len = htons(sizeof(struct tcphdr)); 518 if (inp->inp_af == AF_INET) { 519 ipov->ih_src = in4p_laddr(inp); 520 ipov->ih_dst = in4p_faddr(inp); 521 } 522 #ifdef INET6 523 else if (inp->inp_af == AF_INET6) { 524 /* mapped addr case */ 525 bcopy(&in6p_laddr(inp).s6_addr32[3], &ipov->ih_src, 526 sizeof(ipov->ih_src)); 527 bcopy(&in6p_faddr(inp).s6_addr32[3], &ipov->ih_dst, 528 sizeof(ipov->ih_dst)); 529 } 530 #endif 531 532 /* 533 * Compute the pseudo-header portion of the checksum 534 * now. We incrementally add in the TCP option and 535 * payload lengths later, and then compute the TCP 536 * checksum right before the packet is sent off onto 537 * the wire. 538 */ 539 n->th_sum = in_cksum_phdr(ipov->ih_src.s_addr, 540 ipov->ih_dst.s_addr, 541 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 542 break; 543 } 544 #ifdef INET6 545 case AF_INET6: 546 { 547 struct ip6_hdr *ip6; 548 mtod(m, struct ip *)->ip_v = 6; 549 ip6 = mtod(m, struct ip6_hdr *); 550 ip6->ip6_nxt = IPPROTO_TCP; 551 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 552 ip6->ip6_src = in6p_laddr(inp); 553 ip6->ip6_dst = in6p_faddr(inp); 554 ip6->ip6_flow = in6p_flowinfo(inp) & IPV6_FLOWINFO_MASK; 555 if (ip6_auto_flowlabel) { 556 ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK; 557 ip6->ip6_flow |= 558 (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK); 559 } 560 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 561 ip6->ip6_vfc |= IPV6_VERSION; 562 563 /* 564 * Compute the pseudo-header portion of the checksum 565 * now. We incrementally add in the TCP option and 566 * payload lengths later, and then compute the TCP 567 * checksum right before the packet is sent off onto 568 * the wire. 569 */ 570 n->th_sum = in6_cksum_phdr(&in6p_laddr(inp), 571 &in6p_faddr(inp), htonl(sizeof(struct tcphdr)), 572 htonl(IPPROTO_TCP)); 573 break; 574 } 575 #endif 576 } 577 578 n->th_sport = inp->inp_lport; 579 n->th_dport = inp->inp_fport; 580 581 n->th_seq = 0; 582 n->th_ack = 0; 583 n->th_x2 = 0; 584 n->th_off = 5; 585 n->th_flags = 0; 586 n->th_win = 0; 587 n->th_urp = 0; 588 return m; 589 } 590 591 /* 592 * Send a single message to the TCP at address specified by 593 * the given TCP/IP header. If m == 0, then we make a copy 594 * of the tcpiphdr at ti and send directly to the addressed host. 595 * This is used to force keep alive messages out using the TCP 596 * template for a connection tp->t_template. If flags are given 597 * then we send a message back to the TCP which originated the 598 * segment ti, and discard the mbuf containing it and any other 599 * attached mbufs. 600 * 601 * In any case the ack and sequence number of the transmitted 602 * segment are as specified by the parameters. 603 */ 604 int 605 tcp_respond(struct tcpcb *tp, struct mbuf *mtemplate, struct mbuf *m, 606 struct tcphdr *th0, tcp_seq ack, tcp_seq seq, int flags) 607 { 608 struct route *ro; 609 int error, tlen, win = 0; 610 int hlen; 611 struct ip *ip; 612 #ifdef INET6 613 struct ip6_hdr *ip6; 614 #endif 615 int family; /* family on packet, not inpcb! */ 616 struct tcphdr *th; 617 618 if (tp != NULL && (flags & TH_RST) == 0) { 619 KASSERT(tp->t_inpcb != NULL); 620 621 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 622 } 623 624 th = NULL; /* Quell uninitialized warning */ 625 ip = NULL; 626 #ifdef INET6 627 ip6 = NULL; 628 #endif 629 if (m == NULL) { 630 if (!mtemplate) 631 return EINVAL; 632 633 /* get family information from template */ 634 switch (mtod(mtemplate, struct ip *)->ip_v) { 635 case 4: 636 family = AF_INET; 637 hlen = sizeof(struct ip); 638 break; 639 #ifdef INET6 640 case 6: 641 family = AF_INET6; 642 hlen = sizeof(struct ip6_hdr); 643 break; 644 #endif 645 default: 646 return EAFNOSUPPORT; 647 } 648 649 MGETHDR(m, M_DONTWAIT, MT_HEADER); 650 if (m) { 651 MCLAIM(m, &tcp_tx_mowner); 652 MCLGET(m, M_DONTWAIT); 653 if ((m->m_flags & M_EXT) == 0) { 654 m_free(m); 655 m = NULL; 656 } 657 } 658 if (m == NULL) 659 return ENOBUFS; 660 661 tlen = 0; 662 663 m->m_data += max_linkhdr; 664 bcopy(mtod(mtemplate, void *), mtod(m, void *), 665 mtemplate->m_len); 666 switch (family) { 667 case AF_INET: 668 ip = mtod(m, struct ip *); 669 th = (struct tcphdr *)(ip + 1); 670 break; 671 #ifdef INET6 672 case AF_INET6: 673 ip6 = mtod(m, struct ip6_hdr *); 674 th = (struct tcphdr *)(ip6 + 1); 675 break; 676 #endif 677 } 678 flags = TH_ACK; 679 } else { 680 if ((m->m_flags & M_PKTHDR) == 0) { 681 m_freem(m); 682 return EINVAL; 683 } 684 KASSERT(th0 != NULL); 685 686 /* get family information from m */ 687 switch (mtod(m, struct ip *)->ip_v) { 688 case 4: 689 family = AF_INET; 690 hlen = sizeof(struct ip); 691 ip = mtod(m, struct ip *); 692 break; 693 #ifdef INET6 694 case 6: 695 family = AF_INET6; 696 hlen = sizeof(struct ip6_hdr); 697 ip6 = mtod(m, struct ip6_hdr *); 698 break; 699 #endif 700 default: 701 m_freem(m); 702 return EAFNOSUPPORT; 703 } 704 /* clear h/w csum flags inherited from rx packet */ 705 m->m_pkthdr.csum_flags = 0; 706 707 if ((flags & TH_SYN) == 0 || sizeof(*th0) > (th0->th_off << 2)) 708 tlen = sizeof(*th0); 709 else 710 tlen = th0->th_off << 2; 711 712 if (m->m_len > hlen + tlen && (m->m_flags & M_EXT) == 0 && 713 mtod(m, char *) + hlen == (char *)th0) { 714 m->m_len = hlen + tlen; 715 m_freem(m->m_next); 716 m->m_next = NULL; 717 } else { 718 struct mbuf *n; 719 720 KASSERT(max_linkhdr + hlen + tlen <= MCLBYTES); 721 722 MGETHDR(n, M_DONTWAIT, MT_HEADER); 723 if (n && max_linkhdr + hlen + tlen > MHLEN) { 724 MCLGET(n, M_DONTWAIT); 725 if ((n->m_flags & M_EXT) == 0) { 726 m_freem(n); 727 n = NULL; 728 } 729 } 730 if (!n) { 731 m_freem(m); 732 return ENOBUFS; 733 } 734 735 MCLAIM(n, &tcp_tx_mowner); 736 n->m_data += max_linkhdr; 737 n->m_len = hlen + tlen; 738 m_copyback(n, 0, hlen, mtod(m, void *)); 739 m_copyback(n, hlen, tlen, (void *)th0); 740 741 m_freem(m); 742 m = n; 743 n = NULL; 744 } 745 746 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 747 switch (family) { 748 case AF_INET: 749 ip = mtod(m, struct ip *); 750 th = (struct tcphdr *)(ip + 1); 751 ip->ip_p = IPPROTO_TCP; 752 xchg(ip->ip_dst, ip->ip_src, struct in_addr); 753 ip->ip_p = IPPROTO_TCP; 754 break; 755 #ifdef INET6 756 case AF_INET6: 757 ip6 = mtod(m, struct ip6_hdr *); 758 th = (struct tcphdr *)(ip6 + 1); 759 ip6->ip6_nxt = IPPROTO_TCP; 760 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 761 ip6->ip6_nxt = IPPROTO_TCP; 762 break; 763 #endif 764 } 765 xchg(th->th_dport, th->th_sport, u_int16_t); 766 #undef xchg 767 tlen = 0; /*be friendly with the following code*/ 768 } 769 th->th_seq = htonl(seq); 770 th->th_ack = htonl(ack); 771 th->th_x2 = 0; 772 if ((flags & TH_SYN) == 0) { 773 if (tp) 774 win >>= tp->rcv_scale; 775 if (win > TCP_MAXWIN) 776 win = TCP_MAXWIN; 777 th->th_win = htons((u_int16_t)win); 778 th->th_off = sizeof (struct tcphdr) >> 2; 779 tlen += sizeof(*th); 780 } else { 781 tlen += th->th_off << 2; 782 } 783 m->m_len = hlen + tlen; 784 m->m_pkthdr.len = hlen + tlen; 785 m_reset_rcvif(m); 786 th->th_flags = flags; 787 th->th_urp = 0; 788 789 switch (family) { 790 case AF_INET: 791 { 792 struct ipovly *ipov = (struct ipovly *)ip; 793 memset(ipov->ih_x1, 0, sizeof ipov->ih_x1); 794 ipov->ih_len = htons((u_int16_t)tlen); 795 796 th->th_sum = 0; 797 th->th_sum = in_cksum(m, hlen + tlen); 798 ip->ip_len = htons(hlen + tlen); 799 ip->ip_ttl = ip_defttl; 800 break; 801 } 802 #ifdef INET6 803 case AF_INET6: 804 { 805 th->th_sum = 0; 806 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), 807 tlen); 808 ip6->ip6_plen = htons(tlen); 809 if (tp && tp->t_inpcb->inp_af == AF_INET6) 810 ip6->ip6_hlim = in6pcb_selecthlim_rt(tp->t_inpcb); 811 else 812 ip6->ip6_hlim = ip6_defhlim; 813 ip6->ip6_flow &= ~IPV6_FLOWINFO_MASK; 814 if (ip6_auto_flowlabel) { 815 ip6->ip6_flow |= 816 (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK); 817 } 818 break; 819 } 820 #endif 821 } 822 823 if (tp != NULL && tp->t_inpcb->inp_af == AF_INET) { 824 ro = &tp->t_inpcb->inp_route; 825 KASSERT(family == AF_INET); 826 KASSERT(in_hosteq(ip->ip_dst, in4p_faddr(tp->t_inpcb))); 827 } 828 #ifdef INET6 829 else if (tp != NULL && tp->t_inpcb->inp_af == AF_INET6) { 830 ro = (struct route *)&tp->t_inpcb->inp_route; 831 832 #ifdef DIAGNOSTIC 833 if (family == AF_INET) { 834 if (!IN6_IS_ADDR_V4MAPPED(&in6p_faddr(tp->t_inpcb))) 835 panic("tcp_respond: not mapped addr"); 836 if (memcmp(&ip->ip_dst, 837 &in6p_faddr(tp->t_inpcb).s6_addr32[3], 838 sizeof(ip->ip_dst)) != 0) { 839 panic("tcp_respond: ip_dst != in6p_faddr"); 840 } 841 } else if (family == AF_INET6) { 842 if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, 843 &in6p_faddr(tp->t_inpcb))) 844 panic("tcp_respond: ip6_dst != in6p_faddr"); 845 } else 846 panic("tcp_respond: address family mismatch"); 847 #endif 848 } 849 #endif 850 else 851 ro = NULL; 852 853 switch (family) { 854 case AF_INET: 855 error = ip_output(m, NULL, ro, 856 (tp && tp->t_mtudisc ? IP_MTUDISC : 0), NULL, 857 tp ? tp->t_inpcb : NULL); 858 break; 859 #ifdef INET6 860 case AF_INET6: 861 error = ip6_output(m, NULL, ro, 0, NULL, 862 tp ? tp->t_inpcb : NULL, NULL); 863 break; 864 #endif 865 default: 866 error = EAFNOSUPPORT; 867 break; 868 } 869 870 return error; 871 } 872 873 /* 874 * Template TCPCB. Rather than zeroing a new TCPCB and initializing 875 * a bunch of members individually, we maintain this template for the 876 * static and mostly-static components of the TCPCB, and copy it into 877 * the new TCPCB instead. 878 */ 879 static struct tcpcb tcpcb_template = { 880 .t_srtt = TCPTV_SRTTBASE, 881 .t_rttmin = TCPTV_MIN, 882 883 .snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT, 884 .snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT, 885 .snd_numholes = 0, 886 .snd_cubic_wmax = 0, 887 .snd_cubic_wmax_last = 0, 888 .snd_cubic_ctime = 0, 889 890 .t_partialacks = -1, 891 .t_bytes_acked = 0, 892 .t_sndrexmitpack = 0, 893 .t_rcvoopack = 0, 894 .t_sndzerowin = 0, 895 }; 896 897 /* 898 * Updates the TCPCB template whenever a parameter that would affect 899 * the template is changed. 900 */ 901 void 902 tcp_tcpcb_template(void) 903 { 904 struct tcpcb *tp = &tcpcb_template; 905 int flags; 906 907 tp->t_peermss = tcp_mssdflt; 908 tp->t_ourmss = tcp_mssdflt; 909 tp->t_segsz = tcp_mssdflt; 910 911 flags = 0; 912 if (tcp_do_rfc1323 && tcp_do_win_scale) 913 flags |= TF_REQ_SCALE; 914 if (tcp_do_rfc1323 && tcp_do_timestamps) 915 flags |= TF_REQ_TSTMP; 916 tp->t_flags = flags; 917 918 /* 919 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 920 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives 921 * reasonable initial retransmit time. 922 */ 923 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1); 924 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 925 TCPTV_MIN, TCPTV_REXMTMAX); 926 927 /* Keep Alive */ 928 tp->t_keepinit = MIN(tcp_keepinit, TCP_TIMER_MAXTICKS); 929 tp->t_keepidle = MIN(tcp_keepidle, TCP_TIMER_MAXTICKS); 930 tp->t_keepintvl = MIN(tcp_keepintvl, TCP_TIMER_MAXTICKS); 931 tp->t_keepcnt = MAX(1, MIN(tcp_keepcnt, TCP_TIMER_MAXTICKS)); 932 tp->t_maxidle = tp->t_keepcnt * MIN(tp->t_keepintvl, 933 TCP_TIMER_MAXTICKS/tp->t_keepcnt); 934 935 /* MSL */ 936 tp->t_msl = TCPTV_MSL; 937 } 938 939 /* 940 * Create a new TCP control block, making an 941 * empty reassembly queue and hooking it to the argument 942 * protocol control block. 943 */ 944 struct tcpcb * 945 tcp_newtcpcb(int family, struct inpcb *inp) 946 { 947 struct tcpcb *tp; 948 int i; 949 950 /* XXX Consider using a pool_cache for speed. */ 951 tp = pool_get(&tcpcb_pool, PR_NOWAIT); /* splsoftnet via tcp_usrreq */ 952 if (tp == NULL) 953 return NULL; 954 memcpy(tp, &tcpcb_template, sizeof(*tp)); 955 TAILQ_INIT(&tp->segq); 956 TAILQ_INIT(&tp->timeq); 957 tp->t_family = family; /* may be overridden later on */ 958 TAILQ_INIT(&tp->snd_holes); 959 LIST_INIT(&tp->t_sc); /* XXX can template this */ 960 961 /* Don't sweat this loop; hopefully the compiler will unroll it. */ 962 for (i = 0; i < TCPT_NTIMERS; i++) { 963 callout_init(&tp->t_timer[i], CALLOUT_MPSAFE); 964 TCP_TIMER_INIT(tp, i); 965 } 966 callout_init(&tp->t_delack_ch, CALLOUT_MPSAFE); 967 968 switch (family) { 969 case AF_INET: 970 in4p_ip(inp).ip_ttl = ip_defttl; 971 inp->inp_ppcb = (void *)tp; 972 973 tp->t_inpcb = inp; 974 tp->t_mtudisc = ip_mtudisc; 975 break; 976 #ifdef INET6 977 case AF_INET6: 978 in6p_ip6(inp).ip6_hlim = in6pcb_selecthlim_rt(inp); 979 inp->inp_ppcb = (void *)tp; 980 981 tp->t_inpcb = inp; 982 /* for IPv6, always try to run path MTU discovery */ 983 tp->t_mtudisc = 1; 984 break; 985 #endif /* INET6 */ 986 default: 987 for (i = 0; i < TCPT_NTIMERS; i++) 988 callout_destroy(&tp->t_timer[i]); 989 callout_destroy(&tp->t_delack_ch); 990 pool_put(&tcpcb_pool, tp); /* splsoftnet via tcp_usrreq */ 991 return NULL; 992 } 993 994 /* 995 * Initialize our timebase. When we send timestamps, we take 996 * the delta from tcp_now -- this means each connection always 997 * gets a timebase of 1, which makes it, among other things, 998 * more difficult to determine how long a system has been up, 999 * and thus how many TCP sequence increments have occurred. 1000 * 1001 * We start with 1, because 0 doesn't work with linux, which 1002 * considers timestamp 0 in a SYN packet as a bug and disables 1003 * timestamps. 1004 */ 1005 tp->ts_timebase = tcp_now - 1; 1006 1007 tcp_congctl_select(tp, tcp_congctl_global_name); 1008 1009 return tp; 1010 } 1011 1012 /* 1013 * Drop a TCP connection, reporting 1014 * the specified error. If connection is synchronized, 1015 * then send a RST to peer. 1016 */ 1017 struct tcpcb * 1018 tcp_drop(struct tcpcb *tp, int errno) 1019 { 1020 struct socket *so; 1021 1022 KASSERT(tp->t_inpcb != NULL); 1023 1024 so = tp->t_inpcb->inp_socket; 1025 if (so == NULL) 1026 return NULL; 1027 1028 if (TCPS_HAVERCVDSYN(tp->t_state)) { 1029 tp->t_state = TCPS_CLOSED; 1030 (void) tcp_output(tp); 1031 TCP_STATINC(TCP_STAT_DROPS); 1032 } else 1033 TCP_STATINC(TCP_STAT_CONNDROPS); 1034 if (errno == ETIMEDOUT && tp->t_softerror) 1035 errno = tp->t_softerror; 1036 so->so_error = errno; 1037 return (tcp_close(tp)); 1038 } 1039 1040 /* 1041 * Close a TCP control block: 1042 * discard all space held by the tcp 1043 * discard internet protocol block 1044 * wake up any sleepers 1045 */ 1046 struct tcpcb * 1047 tcp_close(struct tcpcb *tp) 1048 { 1049 struct inpcb *inp; 1050 struct socket *so; 1051 #ifdef RTV_RTT 1052 struct rtentry *rt = NULL; 1053 #endif 1054 struct route *ro; 1055 int j; 1056 1057 inp = tp->t_inpcb; 1058 so = inp->inp_socket; 1059 ro = &inp->inp_route; 1060 1061 #ifdef RTV_RTT 1062 /* 1063 * If we sent enough data to get some meaningful characteristics, 1064 * save them in the routing entry. 'Enough' is arbitrarily 1065 * defined as the sendpipesize (default 4K) * 16. This would 1066 * give us 16 rtt samples assuming we only get one sample per 1067 * window (the usual case on a long haul net). 16 samples is 1068 * enough for the srtt filter to converge to within 5% of the correct 1069 * value; fewer samples and we could save a very bogus rtt. 1070 * 1071 * Don't update the default route's characteristics and don't 1072 * update anything that the user "locked". 1073 */ 1074 if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) && 1075 ro && (rt = rtcache_validate(ro)) != NULL && 1076 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr)) { 1077 u_long i = 0; 1078 1079 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 1080 i = tp->t_srtt * 1081 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1082 if (rt->rt_rmx.rmx_rtt && i) 1083 /* 1084 * filter this update to half the old & half 1085 * the new values, converting scale. 1086 * See route.h and tcp_var.h for a 1087 * description of the scaling constants. 1088 */ 1089 rt->rt_rmx.rmx_rtt = 1090 (rt->rt_rmx.rmx_rtt + i) / 2; 1091 else 1092 rt->rt_rmx.rmx_rtt = i; 1093 } 1094 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 1095 i = tp->t_rttvar * 1096 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2)); 1097 if (rt->rt_rmx.rmx_rttvar && i) 1098 rt->rt_rmx.rmx_rttvar = 1099 (rt->rt_rmx.rmx_rttvar + i) / 2; 1100 else 1101 rt->rt_rmx.rmx_rttvar = i; 1102 } 1103 /* 1104 * update the pipelimit (ssthresh) if it has been updated 1105 * already or if a pipesize was specified & the threshold 1106 * got below half the pipesize. I.e., wait for bad news 1107 * before we start updating, then update on both good 1108 * and bad news. 1109 */ 1110 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 1111 (i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) || 1112 i < (rt->rt_rmx.rmx_sendpipe / 2)) { 1113 /* 1114 * convert the limit from user data bytes to 1115 * packets then to packet data bytes. 1116 */ 1117 i = (i + tp->t_segsz / 2) / tp->t_segsz; 1118 if (i < 2) 1119 i = 2; 1120 i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr)); 1121 if (rt->rt_rmx.rmx_ssthresh) 1122 rt->rt_rmx.rmx_ssthresh = 1123 (rt->rt_rmx.rmx_ssthresh + i) / 2; 1124 else 1125 rt->rt_rmx.rmx_ssthresh = i; 1126 } 1127 } 1128 rtcache_unref(rt, ro); 1129 #endif /* RTV_RTT */ 1130 /* free the reassembly queue, if any */ 1131 TCP_REASS_LOCK(tp); 1132 (void) tcp_freeq(tp); 1133 TCP_REASS_UNLOCK(tp); 1134 1135 /* free the SACK holes list. */ 1136 tcp_free_sackholes(tp); 1137 tcp_congctl_release(tp); 1138 syn_cache_cleanup(tp); 1139 1140 if (tp->t_template) { 1141 m_free(tp->t_template); 1142 tp->t_template = NULL; 1143 } 1144 1145 /* 1146 * Detaching the pcb will unlock the socket/tcpcb, and stopping 1147 * the timers can also drop the lock. We need to prevent access 1148 * to the tcpcb as it's half torn down. Flag the pcb as dead 1149 * (prevents access by timers) and only then detach it. 1150 */ 1151 tp->t_flags |= TF_DEAD; 1152 inp->inp_ppcb = NULL; 1153 soisdisconnected(so); 1154 inpcb_destroy(inp); 1155 /* 1156 * pcb is no longer visble elsewhere, so we can safely release 1157 * the lock in callout_halt() if needed. 1158 */ 1159 TCP_STATINC(TCP_STAT_CLOSED); 1160 for (j = 0; j < TCPT_NTIMERS; j++) { 1161 callout_halt(&tp->t_timer[j], softnet_lock); 1162 callout_destroy(&tp->t_timer[j]); 1163 } 1164 callout_halt(&tp->t_delack_ch, softnet_lock); 1165 callout_destroy(&tp->t_delack_ch); 1166 pool_put(&tcpcb_pool, tp); 1167 1168 return NULL; 1169 } 1170 1171 int 1172 tcp_freeq(struct tcpcb *tp) 1173 { 1174 struct ipqent *qe; 1175 int rv = 0; 1176 1177 TCP_REASS_LOCK_CHECK(tp); 1178 1179 while ((qe = TAILQ_FIRST(&tp->segq)) != NULL) { 1180 TAILQ_REMOVE(&tp->segq, qe, ipqe_q); 1181 TAILQ_REMOVE(&tp->timeq, qe, ipqe_timeq); 1182 m_freem(qe->ipqe_m); 1183 tcpipqent_free(qe); 1184 rv = 1; 1185 } 1186 tp->t_segqlen = 0; 1187 KASSERT(TAILQ_EMPTY(&tp->timeq)); 1188 return (rv); 1189 } 1190 1191 void 1192 tcp_fasttimo(void) 1193 { 1194 if (tcp_drainwanted) { 1195 tcp_drain(); 1196 tcp_drainwanted = 0; 1197 } 1198 } 1199 1200 void 1201 tcp_drainstub(void) 1202 { 1203 tcp_drainwanted = 1; 1204 } 1205 1206 /* 1207 * Protocol drain routine. Called when memory is in short supply. 1208 * Called from pr_fasttimo thus a callout context. 1209 */ 1210 void 1211 tcp_drain(void) 1212 { 1213 struct inpcb *inp; 1214 struct tcpcb *tp; 1215 1216 mutex_enter(softnet_lock); 1217 KERNEL_LOCK(1, NULL); 1218 1219 /* 1220 * Free the sequence queue of all TCP connections. 1221 */ 1222 TAILQ_FOREACH(inp, &tcbtable.inpt_queue, inp_queue) { 1223 tp = intotcpcb(inp); 1224 if (tp != NULL) { 1225 /* 1226 * If the tcpcb is already busy, 1227 * just bail out now. 1228 */ 1229 if (tcp_reass_lock_try(tp) == 0) 1230 continue; 1231 if (tcp_freeq(tp)) 1232 TCP_STATINC(TCP_STAT_CONNSDRAINED); 1233 TCP_REASS_UNLOCK(tp); 1234 } 1235 } 1236 1237 KERNEL_UNLOCK_ONE(NULL); 1238 mutex_exit(softnet_lock); 1239 } 1240 1241 /* 1242 * Notify a tcp user of an asynchronous error; 1243 * store error as soft error, but wake up user 1244 * (for now, won't do anything until can select for soft error). 1245 */ 1246 void 1247 tcp_notify(struct inpcb *inp, int error) 1248 { 1249 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 1250 struct socket *so = inp->inp_socket; 1251 1252 /* 1253 * Ignore some errors if we are hooked up. 1254 * If connection hasn't completed, has retransmitted several times, 1255 * and receives a second error, give up now. This is better 1256 * than waiting a long time to establish a connection that 1257 * can never complete. 1258 */ 1259 if (tp->t_state == TCPS_ESTABLISHED && 1260 (error == EHOSTUNREACH || error == ENETUNREACH || 1261 error == EHOSTDOWN)) { 1262 return; 1263 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 && 1264 tp->t_rxtshift > 3 && tp->t_softerror) 1265 so->so_error = error; 1266 else 1267 tp->t_softerror = error; 1268 cv_broadcast(&so->so_cv); 1269 sorwakeup(so); 1270 sowwakeup(so); 1271 } 1272 1273 #ifdef INET6 1274 void * 1275 tcp6_ctlinput(int cmd, const struct sockaddr *sa, void *d) 1276 { 1277 struct tcphdr th; 1278 void (*notify)(struct inpcb *, int) = tcp_notify; 1279 int nmatch; 1280 struct ip6_hdr *ip6; 1281 const struct sockaddr_in6 *sa6_src = NULL; 1282 const struct sockaddr_in6 *sa6 = (const struct sockaddr_in6 *)sa; 1283 struct mbuf *m; 1284 int off; 1285 1286 if (sa->sa_family != AF_INET6 || 1287 sa->sa_len != sizeof(struct sockaddr_in6)) 1288 return NULL; 1289 if ((unsigned)cmd >= PRC_NCMDS) 1290 return NULL; 1291 else if (cmd == PRC_QUENCH) { 1292 /* 1293 * Don't honor ICMP Source Quench messages meant for 1294 * TCP connections. 1295 */ 1296 return NULL; 1297 } else if (PRC_IS_REDIRECT(cmd)) 1298 notify = in6pcb_rtchange, d = NULL; 1299 else if (cmd == PRC_MSGSIZE) 1300 ; /* special code is present, see below */ 1301 else if (cmd == PRC_HOSTDEAD) 1302 d = NULL; 1303 else if (inet6ctlerrmap[cmd] == 0) 1304 return NULL; 1305 1306 /* if the parameter is from icmp6, decode it. */ 1307 if (d != NULL) { 1308 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d; 1309 m = ip6cp->ip6c_m; 1310 ip6 = ip6cp->ip6c_ip6; 1311 off = ip6cp->ip6c_off; 1312 sa6_src = ip6cp->ip6c_src; 1313 } else { 1314 m = NULL; 1315 ip6 = NULL; 1316 sa6_src = &sa6_any; 1317 off = 0; 1318 } 1319 1320 if (ip6) { 1321 /* check if we can safely examine src and dst ports */ 1322 if (m->m_pkthdr.len < off + sizeof(th)) { 1323 if (cmd == PRC_MSGSIZE) 1324 icmp6_mtudisc_update((struct ip6ctlparam *)d, 0); 1325 return NULL; 1326 } 1327 1328 memset(&th, 0, sizeof(th)); 1329 m_copydata(m, off, sizeof(th), (void *)&th); 1330 1331 if (cmd == PRC_MSGSIZE) { 1332 int valid = 0; 1333 1334 /* 1335 * Check to see if we have a valid TCP connection 1336 * corresponding to the address in the ICMPv6 message 1337 * payload. 1338 */ 1339 if (in6pcb_lookup(&tcbtable, &sa6->sin6_addr, 1340 th.th_dport, 1341 (const struct in6_addr *)&sa6_src->sin6_addr, 1342 th.th_sport, 0, 0)) 1343 valid++; 1344 1345 /* 1346 * Depending on the value of "valid" and routing table 1347 * size (mtudisc_{hi,lo}wat), we will: 1348 * - recalcurate the new MTU and create the 1349 * corresponding routing entry, or 1350 * - ignore the MTU change notification. 1351 */ 1352 icmp6_mtudisc_update((struct ip6ctlparam *)d, valid); 1353 1354 /* 1355 * no need to call in6pcb_notify, it should have been 1356 * called via callback if necessary 1357 */ 1358 return NULL; 1359 } 1360 1361 nmatch = in6pcb_notify(&tcbtable, sa, th.th_dport, 1362 (const struct sockaddr *)sa6_src, th.th_sport, cmd, NULL, notify); 1363 if (nmatch == 0 && syn_cache_count && 1364 (inet6ctlerrmap[cmd] == EHOSTUNREACH || 1365 inet6ctlerrmap[cmd] == ENETUNREACH || 1366 inet6ctlerrmap[cmd] == EHOSTDOWN)) 1367 syn_cache_unreach((const struct sockaddr *)sa6_src, 1368 sa, &th); 1369 } else { 1370 (void) in6pcb_notify(&tcbtable, sa, 0, 1371 (const struct sockaddr *)sa6_src, 0, cmd, NULL, notify); 1372 } 1373 1374 return NULL; 1375 } 1376 #endif 1377 1378 /* assumes that ip header and tcp header are contiguous on mbuf */ 1379 void * 1380 tcp_ctlinput(int cmd, const struct sockaddr *sa, void *v) 1381 { 1382 struct ip *ip = v; 1383 struct tcphdr *th; 1384 struct icmp *icp; 1385 extern const int inetctlerrmap[]; 1386 void (*notify)(struct inpcb *, int) = tcp_notify; 1387 int errno; 1388 int nmatch; 1389 struct tcpcb *tp; 1390 u_int mtu; 1391 tcp_seq seq; 1392 struct inpcb *inp; 1393 #ifdef INET6 1394 struct in6_addr src6, dst6; 1395 #endif 1396 1397 if (sa->sa_family != AF_INET || 1398 sa->sa_len != sizeof(struct sockaddr_in)) 1399 return NULL; 1400 if ((unsigned)cmd >= PRC_NCMDS) 1401 return NULL; 1402 errno = inetctlerrmap[cmd]; 1403 if (cmd == PRC_QUENCH) 1404 /* 1405 * Don't honor ICMP Source Quench messages meant for 1406 * TCP connections. 1407 */ 1408 return NULL; 1409 else if (PRC_IS_REDIRECT(cmd)) 1410 notify = inpcb_rtchange, ip = 0; 1411 else if (cmd == PRC_MSGSIZE && ip && ip->ip_v == 4) { 1412 /* 1413 * Check to see if we have a valid TCP connection 1414 * corresponding to the address in the ICMP message 1415 * payload. 1416 * 1417 * Boundary check is made in icmp_input(), with ICMP_ADVLENMIN. 1418 */ 1419 th = (struct tcphdr *)((char *)ip + (ip->ip_hl << 2)); 1420 #ifdef INET6 1421 in6_in_2_v4mapin6(&ip->ip_src, &src6); 1422 in6_in_2_v4mapin6(&ip->ip_dst, &dst6); 1423 #endif 1424 if ((inp = inpcb_lookup(&tcbtable, ip->ip_dst, 1425 th->th_dport, ip->ip_src, th->th_sport, 0)) != NULL) 1426 ; 1427 #ifdef INET6 1428 else if ((inp = in6pcb_lookup(&tcbtable, &dst6, 1429 th->th_dport, &src6, th->th_sport, 0, 0)) != NULL) 1430 ; 1431 #endif 1432 else 1433 return NULL; 1434 1435 /* 1436 * Now that we've validated that we are actually communicating 1437 * with the host indicated in the ICMP message, locate the 1438 * ICMP header, recalculate the new MTU, and create the 1439 * corresponding routing entry. 1440 */ 1441 icp = (struct icmp *)((char *)ip - 1442 offsetof(struct icmp, icmp_ip)); 1443 tp = intotcpcb(inp); 1444 if (tp == NULL) 1445 return NULL; 1446 seq = ntohl(th->th_seq); 1447 if (SEQ_LT(seq, tp->snd_una) || SEQ_GT(seq, tp->snd_max)) 1448 return NULL; 1449 /* 1450 * If the ICMP message advertises a Next-Hop MTU 1451 * equal or larger than the maximum packet size we have 1452 * ever sent, drop the message. 1453 */ 1454 mtu = (u_int)ntohs(icp->icmp_nextmtu); 1455 if (mtu >= tp->t_pmtud_mtu_sent) 1456 return NULL; 1457 if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) { 1458 /* 1459 * Calculate new MTU, and create corresponding 1460 * route (traditional PMTUD). 1461 */ 1462 tp->t_flags &= ~TF_PMTUD_PEND; 1463 icmp_mtudisc(icp, ip->ip_dst); 1464 } else { 1465 /* 1466 * Record the information got in the ICMP 1467 * message; act on it later. 1468 * If we had already recorded an ICMP message, 1469 * replace the old one only if the new message 1470 * refers to an older TCP segment 1471 */ 1472 if (tp->t_flags & TF_PMTUD_PEND) { 1473 if (SEQ_LT(tp->t_pmtud_th_seq, seq)) 1474 return NULL; 1475 } else 1476 tp->t_flags |= TF_PMTUD_PEND; 1477 tp->t_pmtud_th_seq = seq; 1478 tp->t_pmtud_nextmtu = icp->icmp_nextmtu; 1479 tp->t_pmtud_ip_len = icp->icmp_ip.ip_len; 1480 tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl; 1481 } 1482 return NULL; 1483 } else if (cmd == PRC_HOSTDEAD) 1484 ip = 0; 1485 else if (errno == 0) 1486 return NULL; 1487 if (ip && ip->ip_v == 4 && sa->sa_family == AF_INET) { 1488 th = (struct tcphdr *)((char *)ip + (ip->ip_hl << 2)); 1489 nmatch = inpcb_notify(&tcbtable, satocsin(sa)->sin_addr, 1490 th->th_dport, ip->ip_src, th->th_sport, errno, notify); 1491 if (nmatch == 0 && syn_cache_count && 1492 (inetctlerrmap[cmd] == EHOSTUNREACH || 1493 inetctlerrmap[cmd] == ENETUNREACH || 1494 inetctlerrmap[cmd] == EHOSTDOWN)) { 1495 struct sockaddr_in sin; 1496 memset(&sin, 0, sizeof(sin)); 1497 sin.sin_len = sizeof(sin); 1498 sin.sin_family = AF_INET; 1499 sin.sin_port = th->th_sport; 1500 sin.sin_addr = ip->ip_src; 1501 syn_cache_unreach((struct sockaddr *)&sin, sa, th); 1502 } 1503 1504 /* XXX mapped address case */ 1505 } else 1506 inpcb_notifyall(&tcbtable, satocsin(sa)->sin_addr, errno, 1507 notify); 1508 return NULL; 1509 } 1510 1511 /* 1512 * When a source quench is received, we are being notified of congestion. 1513 * Close the congestion window down to the Loss Window (one segment). 1514 * We will gradually open it again as we proceed. 1515 */ 1516 void 1517 tcp_quench(struct inpcb *inp) 1518 { 1519 struct tcpcb *tp = intotcpcb(inp); 1520 1521 if (tp) { 1522 tp->snd_cwnd = tp->t_segsz; 1523 tp->t_bytes_acked = 0; 1524 } 1525 } 1526 1527 /* 1528 * Path MTU Discovery handlers. 1529 */ 1530 void 1531 tcp_mtudisc_callback(struct in_addr faddr) 1532 { 1533 #ifdef INET6 1534 struct in6_addr in6; 1535 #endif 1536 1537 inpcb_notifyall(&tcbtable, faddr, EMSGSIZE, tcp_mtudisc); 1538 #ifdef INET6 1539 in6_in_2_v4mapin6(&faddr, &in6); 1540 tcp6_mtudisc_callback(&in6); 1541 #endif 1542 } 1543 1544 /* 1545 * On receipt of path MTU corrections, flush old route and replace it 1546 * with the new one. Retransmit all unacknowledged packets, to ensure 1547 * that all packets will be received. 1548 */ 1549 void 1550 tcp_mtudisc(struct inpcb *inp, int errno) 1551 { 1552 struct tcpcb *tp = intotcpcb(inp); 1553 struct rtentry *rt; 1554 1555 if (tp == NULL) 1556 return; 1557 1558 rt = inpcb_rtentry(inp); 1559 if (rt != NULL) { 1560 /* 1561 * If this was not a host route, remove and realloc. 1562 */ 1563 if ((rt->rt_flags & RTF_HOST) == 0) { 1564 inpcb_rtentry_unref(rt, inp); 1565 inpcb_rtchange(inp, errno); 1566 if ((rt = inpcb_rtentry(inp)) == NULL) 1567 return; 1568 } 1569 1570 /* 1571 * Slow start out of the error condition. We 1572 * use the MTU because we know it's smaller 1573 * than the previously transmitted segment. 1574 * 1575 * Note: This is more conservative than the 1576 * suggestion in draft-floyd-incr-init-win-03. 1577 */ 1578 if (rt->rt_rmx.rmx_mtu != 0) 1579 tp->snd_cwnd = 1580 TCP_INITIAL_WINDOW(tcp_init_win, 1581 rt->rt_rmx.rmx_mtu); 1582 inpcb_rtentry_unref(rt, inp); 1583 } 1584 1585 /* 1586 * Resend unacknowledged packets. 1587 */ 1588 tp->snd_nxt = tp->sack_newdata = tp->snd_una; 1589 tcp_output(tp); 1590 } 1591 1592 #ifdef INET6 1593 /* 1594 * Path MTU Discovery handlers. 1595 */ 1596 void 1597 tcp6_mtudisc_callback(struct in6_addr *faddr) 1598 { 1599 struct sockaddr_in6 sin6; 1600 1601 memset(&sin6, 0, sizeof(sin6)); 1602 sin6.sin6_family = AF_INET6; 1603 sin6.sin6_len = sizeof(struct sockaddr_in6); 1604 sin6.sin6_addr = *faddr; 1605 (void) in6pcb_notify(&tcbtable, (struct sockaddr *)&sin6, 0, 1606 (const struct sockaddr *)&sa6_any, 0, PRC_MSGSIZE, NULL, tcp6_mtudisc); 1607 } 1608 1609 void 1610 tcp6_mtudisc(struct inpcb *inp, int errno) 1611 { 1612 struct tcpcb *tp = intotcpcb(inp); 1613 struct rtentry *rt; 1614 1615 if (tp == NULL) 1616 return; 1617 1618 rt = in6pcb_rtentry(inp); 1619 if (rt != NULL) { 1620 /* 1621 * If this was not a host route, remove and realloc. 1622 */ 1623 if ((rt->rt_flags & RTF_HOST) == 0) { 1624 in6pcb_rtentry_unref(rt, inp); 1625 in6pcb_rtchange(inp, errno); 1626 rt = in6pcb_rtentry(inp); 1627 if (rt == NULL) 1628 return; 1629 } 1630 1631 /* 1632 * Slow start out of the error condition. We 1633 * use the MTU because we know it's smaller 1634 * than the previously transmitted segment. 1635 * 1636 * Note: This is more conservative than the 1637 * suggestion in draft-floyd-incr-init-win-03. 1638 */ 1639 if (rt->rt_rmx.rmx_mtu != 0) { 1640 tp->snd_cwnd = TCP_INITIAL_WINDOW(tcp_init_win, 1641 rt->rt_rmx.rmx_mtu); 1642 } 1643 in6pcb_rtentry_unref(rt, inp); 1644 } 1645 1646 /* 1647 * Resend unacknowledged packets. 1648 */ 1649 tp->snd_nxt = tp->sack_newdata = tp->snd_una; 1650 tcp_output(tp); 1651 } 1652 #endif /* INET6 */ 1653 1654 /* 1655 * Compute the MSS to advertise to the peer. Called only during 1656 * the 3-way handshake. If we are the server (peer initiated 1657 * connection), we are called with a pointer to the interface 1658 * on which the SYN packet arrived. If we are the client (we 1659 * initiated connection), we are called with a pointer to the 1660 * interface out which this connection should go. 1661 * 1662 * NOTE: Do not subtract IP option/extension header size nor IPsec 1663 * header size from MSS advertisement. MSS option must hold the maximum 1664 * segment size we can accept, so it must always be: 1665 * max(if mtu) - ip header - tcp header 1666 */ 1667 u_long 1668 tcp_mss_to_advertise(const struct ifnet *ifp, int af) 1669 { 1670 extern u_long in_maxmtu; 1671 u_long mss = 0; 1672 u_long hdrsiz; 1673 1674 /* 1675 * In order to avoid defeating path MTU discovery on the peer, 1676 * we advertise the max MTU of all attached networks as our MSS, 1677 * per RFC 1191, section 3.1. 1678 * 1679 * We provide the option to advertise just the MTU of 1680 * the interface on which we hope this connection will 1681 * be receiving. If we are responding to a SYN, we 1682 * will have a pretty good idea about this, but when 1683 * initiating a connection there is a bit more doubt. 1684 * 1685 * We also need to ensure that loopback has a large enough 1686 * MSS, as the loopback MTU is never included in in_maxmtu. 1687 */ 1688 1689 if (ifp != NULL) 1690 switch (af) { 1691 #ifdef INET6 1692 case AF_INET6: /* FALLTHROUGH */ 1693 #endif 1694 case AF_INET: 1695 mss = ifp->if_mtu; 1696 break; 1697 } 1698 1699 if (tcp_mss_ifmtu == 0) 1700 switch (af) { 1701 #ifdef INET6 1702 case AF_INET6: /* FALLTHROUGH */ 1703 #endif 1704 case AF_INET: 1705 mss = uimax(in_maxmtu, mss); 1706 break; 1707 } 1708 1709 switch (af) { 1710 case AF_INET: 1711 hdrsiz = sizeof(struct ip); 1712 break; 1713 #ifdef INET6 1714 case AF_INET6: 1715 hdrsiz = sizeof(struct ip6_hdr); 1716 break; 1717 #endif 1718 default: 1719 hdrsiz = 0; 1720 break; 1721 } 1722 hdrsiz += sizeof(struct tcphdr); 1723 if (mss > hdrsiz) 1724 mss -= hdrsiz; 1725 1726 mss = uimax(tcp_mssdflt, mss); 1727 return (mss); 1728 } 1729 1730 /* 1731 * Set connection variables based on the peer's advertised MSS. 1732 * We are passed the TCPCB for the actual connection. If we 1733 * are the server, we are called by the compressed state engine 1734 * when the 3-way handshake is complete. If we are the client, 1735 * we are called when we receive the SYN,ACK from the server. 1736 * 1737 * NOTE: Our advertised MSS value must be initialized in the TCPCB 1738 * before this routine is called! 1739 */ 1740 void 1741 tcp_mss_from_peer(struct tcpcb *tp, int offer) 1742 { 1743 struct socket *so; 1744 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1745 struct rtentry *rt; 1746 #endif 1747 u_long bufsize; 1748 int mss; 1749 1750 KASSERT(tp->t_inpcb != NULL); 1751 1752 so = NULL; 1753 rt = NULL; 1754 1755 so = tp->t_inpcb->inp_socket; 1756 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1757 rt = inpcb_rtentry(tp->t_inpcb); 1758 #endif 1759 1760 /* 1761 * As per RFC1122, use the default MSS value, unless they 1762 * sent us an offer. Do not accept offers less than 256 bytes. 1763 */ 1764 mss = tcp_mssdflt; 1765 if (offer) 1766 mss = offer; 1767 mss = uimax(mss, 256); /* sanity */ 1768 tp->t_peermss = mss; 1769 mss -= tcp_optlen(tp); 1770 if (tp->t_inpcb->inp_af == AF_INET) 1771 mss -= ip_optlen(tp->t_inpcb); 1772 #ifdef INET6 1773 if (tp->t_inpcb->inp_af == AF_INET6) 1774 mss -= ip6_optlen(tp->t_inpcb); 1775 #endif 1776 /* 1777 * XXX XXX What if mss goes negative or zero? This can happen if a 1778 * socket has large IPv6 options. We crash below. 1779 */ 1780 1781 /* 1782 * If there's a pipesize, change the socket buffer to that size. 1783 * Make the socket buffer an integral number of MSS units. If 1784 * the MSS is larger than the socket buffer, artificially decrease 1785 * the MSS. 1786 */ 1787 #ifdef RTV_SPIPE 1788 if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0) 1789 bufsize = rt->rt_rmx.rmx_sendpipe; 1790 else 1791 #endif 1792 { 1793 KASSERT(so != NULL); 1794 bufsize = so->so_snd.sb_hiwat; 1795 } 1796 if (bufsize < mss) 1797 mss = bufsize; 1798 else { 1799 bufsize = roundup(bufsize, mss); 1800 if (bufsize > sb_max) 1801 bufsize = sb_max; 1802 (void) sbreserve(&so->so_snd, bufsize, so); 1803 } 1804 tp->t_segsz = mss; 1805 1806 #ifdef RTV_SSTHRESH 1807 if (rt != NULL && rt->rt_rmx.rmx_ssthresh) { 1808 /* 1809 * There's some sort of gateway or interface buffer 1810 * limit on the path. Use this to set the slow 1811 * start threshold, but set the threshold to no less 1812 * than 2 * MSS. 1813 */ 1814 tp->snd_ssthresh = uimax(2 * mss, rt->rt_rmx.rmx_ssthresh); 1815 } 1816 #endif 1817 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH) 1818 inpcb_rtentry_unref(rt, tp->t_inpcb); 1819 #endif 1820 } 1821 1822 /* 1823 * Processing necessary when a TCP connection is established. 1824 */ 1825 void 1826 tcp_established(struct tcpcb *tp) 1827 { 1828 struct socket *so; 1829 #ifdef RTV_RPIPE 1830 struct rtentry *rt; 1831 #endif 1832 u_long bufsize; 1833 1834 KASSERT(tp->t_inpcb != NULL); 1835 1836 so = NULL; 1837 rt = NULL; 1838 1839 /* This is a while() to reduce the dreadful stairstepping below */ 1840 while (tp->t_inpcb->inp_af == AF_INET) { 1841 so = tp->t_inpcb->inp_socket; 1842 #if defined(RTV_RPIPE) 1843 rt = inpcb_rtentry(tp->t_inpcb); 1844 #endif 1845 if (__predict_true(tcp_msl_enable)) { 1846 if (in4p_laddr(tp->t_inpcb).s_addr == INADDR_LOOPBACK) { 1847 tp->t_msl = tcp_msl_loop ? tcp_msl_loop : (TCPTV_MSL >> 2); 1848 break; 1849 } 1850 1851 if (__predict_false(tcp_rttlocal)) { 1852 /* This may be adjusted by tcp_input */ 1853 tp->t_msl = tcp_msl_local ? tcp_msl_local : (TCPTV_MSL >> 1); 1854 break; 1855 } 1856 if (in_localaddr(in4p_faddr(tp->t_inpcb))) { 1857 tp->t_msl = tcp_msl_local ? tcp_msl_local : (TCPTV_MSL >> 1); 1858 break; 1859 } 1860 } 1861 tp->t_msl = tcp_msl_remote ? tcp_msl_remote : TCPTV_MSL; 1862 break; 1863 } 1864 1865 /* Clamp to a reasonable range. */ 1866 tp->t_msl = MIN(tp->t_msl, TCP_MAXMSL); 1867 1868 #ifdef INET6 1869 while (tp->t_inpcb->inp_af == AF_INET6) { 1870 so = tp->t_inpcb->inp_socket; 1871 #if defined(RTV_RPIPE) 1872 rt = in6pcb_rtentry(tp->t_inpcb); 1873 #endif 1874 if (__predict_true(tcp_msl_enable)) { 1875 extern const struct in6_addr in6addr_loopback; 1876 1877 if (IN6_ARE_ADDR_EQUAL(&in6p_laddr(tp->t_inpcb), 1878 &in6addr_loopback)) { 1879 tp->t_msl = tcp_msl_loop ? tcp_msl_loop : (TCPTV_MSL >> 2); 1880 break; 1881 } 1882 1883 if (__predict_false(tcp_rttlocal)) { 1884 /* This may be adjusted by tcp_input */ 1885 tp->t_msl = tcp_msl_local ? tcp_msl_local : (TCPTV_MSL >> 1); 1886 break; 1887 } 1888 if (in6_localaddr(&in6p_faddr(tp->t_inpcb))) { 1889 tp->t_msl = tcp_msl_local ? tcp_msl_local : (TCPTV_MSL >> 1); 1890 break; 1891 } 1892 } 1893 tp->t_msl = tcp_msl_remote ? tcp_msl_remote : TCPTV_MSL; 1894 break; 1895 } 1896 1897 /* Clamp to a reasonable range. */ 1898 tp->t_msl = MIN(tp->t_msl, TCP_MAXMSL); 1899 #endif 1900 1901 tp->t_state = TCPS_ESTABLISHED; 1902 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle); 1903 1904 #ifdef RTV_RPIPE 1905 if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0) 1906 bufsize = rt->rt_rmx.rmx_recvpipe; 1907 else 1908 #endif 1909 { 1910 KASSERT(so != NULL); 1911 bufsize = so->so_rcv.sb_hiwat; 1912 } 1913 if (bufsize > tp->t_ourmss) { 1914 bufsize = roundup(bufsize, tp->t_ourmss); 1915 if (bufsize > sb_max) 1916 bufsize = sb_max; 1917 (void) sbreserve(&so->so_rcv, bufsize, so); 1918 } 1919 #ifdef RTV_RPIPE 1920 inpcb_rtentry_unref(rt, tp->t_inpcb); 1921 #endif 1922 } 1923 1924 /* 1925 * Check if there's an initial rtt or rttvar. Convert from the 1926 * route-table units to scaled multiples of the slow timeout timer. 1927 * Called only during the 3-way handshake. 1928 */ 1929 void 1930 tcp_rmx_rtt(struct tcpcb *tp) 1931 { 1932 #ifdef RTV_RTT 1933 struct rtentry *rt = NULL; 1934 int rtt; 1935 1936 KASSERT(tp->t_inpcb != NULL); 1937 1938 rt = inpcb_rtentry(tp->t_inpcb); 1939 if (rt == NULL) 1940 return; 1941 1942 if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) { 1943 /* 1944 * XXX The lock bit for MTU indicates that the value 1945 * is also a minimum value; this is subject to time. 1946 */ 1947 if (rt->rt_rmx.rmx_locks & RTV_RTT) 1948 TCPT_RANGESET(tp->t_rttmin, 1949 rtt / (RTM_RTTUNIT / PR_SLOWHZ), 1950 TCPTV_MIN, TCPTV_REXMTMAX); 1951 tp->t_srtt = rtt / 1952 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2)); 1953 if (rt->rt_rmx.rmx_rttvar) { 1954 tp->t_rttvar = rt->rt_rmx.rmx_rttvar / 1955 ((RTM_RTTUNIT / PR_SLOWHZ) >> 1956 (TCP_RTTVAR_SHIFT + 2)); 1957 } else { 1958 /* Default variation is +- 1 rtt */ 1959 tp->t_rttvar = 1960 tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT); 1961 } 1962 TCPT_RANGESET(tp->t_rxtcur, 1963 ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2), 1964 tp->t_rttmin, TCPTV_REXMTMAX); 1965 } 1966 inpcb_rtentry_unref(rt, tp->t_inpcb); 1967 #endif 1968 } 1969 1970 tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */ 1971 1972 /* 1973 * Get a new sequence value given a tcp control block 1974 */ 1975 tcp_seq 1976 tcp_new_iss(struct tcpcb *tp) 1977 { 1978 1979 if (tp->t_inpcb->inp_af == AF_INET) { 1980 return tcp_new_iss1(&in4p_laddr(tp->t_inpcb), 1981 &in4p_faddr(tp->t_inpcb), tp->t_inpcb->inp_lport, 1982 tp->t_inpcb->inp_fport, sizeof(in4p_laddr(tp->t_inpcb))); 1983 } 1984 #ifdef INET6 1985 if (tp->t_inpcb->inp_af == AF_INET6) { 1986 return tcp_new_iss1(&in6p_laddr(tp->t_inpcb), 1987 &in6p_faddr(tp->t_inpcb), tp->t_inpcb->inp_lport, 1988 tp->t_inpcb->inp_fport, sizeof(in6p_laddr(tp->t_inpcb))); 1989 } 1990 #endif 1991 1992 panic("tcp_new_iss: unreachable"); 1993 } 1994 1995 static u_int8_t tcp_iss_secret[16]; /* 128 bits; should be plenty */ 1996 1997 /* 1998 * Initialize RFC 1948 ISS Secret 1999 */ 2000 static int 2001 tcp_iss_secret_init(void) 2002 { 2003 cprng_strong(kern_cprng, 2004 tcp_iss_secret, sizeof(tcp_iss_secret), 0); 2005 2006 return 0; 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) 2015 { 2016 tcp_seq tcp_iss; 2017 2018 if (tcp_do_rfc1948) { 2019 MD5_CTX ctx; 2020 u_int8_t hash[16]; /* XXX MD5 knowledge */ 2021 static ONCE_DECL(tcp_iss_secret_control); 2022 2023 /* 2024 * If we haven't been here before, initialize our cryptographic 2025 * hash secret. 2026 */ 2027 RUN_ONCE(&tcp_iss_secret_control, tcp_iss_secret_init); 2028 2029 /* 2030 * Compute the base value of the ISS. It is a hash 2031 * of (saddr, sport, daddr, dport, secret). 2032 */ 2033 MD5Init(&ctx); 2034 2035 MD5Update(&ctx, (u_char *) laddr, addrsz); 2036 MD5Update(&ctx, (u_char *) &lport, sizeof(lport)); 2037 2038 MD5Update(&ctx, (u_char *) faddr, addrsz); 2039 MD5Update(&ctx, (u_char *) &fport, sizeof(fport)); 2040 2041 MD5Update(&ctx, tcp_iss_secret, sizeof(tcp_iss_secret)); 2042 2043 MD5Final(hash, &ctx); 2044 2045 memcpy(&tcp_iss, hash, sizeof(tcp_iss)); 2046 2047 #ifdef TCPISS_DEBUG 2048 printf("ISS hash 0x%08x, ", tcp_iss); 2049 #endif 2050 } else { 2051 /* 2052 * Randomize. 2053 */ 2054 tcp_iss = cprng_fast32() & TCP_ISS_RANDOM_MASK; 2055 #ifdef TCPISS_DEBUG 2056 printf("ISS random 0x%08x, ", tcp_iss); 2057 #endif 2058 } 2059 2060 /* 2061 * Add the offset in to the computed value. 2062 */ 2063 tcp_iss += tcp_iss_seq; 2064 #ifdef TCPISS_DEBUG 2065 printf("ISS %08x\n", tcp_iss); 2066 #endif 2067 return tcp_iss; 2068 } 2069 2070 #if defined(IPSEC) 2071 /* compute ESP/AH header size for TCP, including outer IP header. */ 2072 size_t 2073 ipsec4_hdrsiz_tcp(struct tcpcb *tp) 2074 { 2075 struct inpcb *inp; 2076 size_t hdrsiz; 2077 2078 /* XXX mapped addr case (tp->t_inpcb) */ 2079 if (!tp || !tp->t_template || !(inp = tp->t_inpcb)) 2080 return 0; 2081 switch (tp->t_family) { 2082 case AF_INET: 2083 /* XXX: should use correct direction. */ 2084 hdrsiz = ipsec_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, inp); 2085 break; 2086 default: 2087 hdrsiz = 0; 2088 break; 2089 } 2090 2091 return hdrsiz; 2092 } 2093 2094 #ifdef INET6 2095 size_t 2096 ipsec6_hdrsiz_tcp(struct tcpcb *tp) 2097 { 2098 struct inpcb *inp; 2099 size_t hdrsiz; 2100 2101 if (!tp || !tp->t_template || !(inp = tp->t_inpcb)) 2102 return 0; 2103 switch (tp->t_family) { 2104 case AF_INET6: 2105 /* XXX: should use correct direction. */ 2106 hdrsiz = ipsec_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, inp); 2107 break; 2108 case AF_INET: 2109 /* mapped address case - tricky */ 2110 default: 2111 hdrsiz = 0; 2112 break; 2113 } 2114 2115 return hdrsiz; 2116 } 2117 #endif 2118 #endif /*IPSEC*/ 2119 2120 /* 2121 * Determine the length of the TCP options for this connection. 2122 * 2123 * XXX: What do we do for SACK, when we add that? Just reserve 2124 * all of the space? Otherwise we can't exactly be incrementing 2125 * cwnd by an amount that varies depending on the amount we last 2126 * had to SACK! 2127 */ 2128 2129 u_int 2130 tcp_optlen(struct tcpcb *tp) 2131 { 2132 u_int optlen; 2133 2134 optlen = 0; 2135 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 2136 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 2137 optlen += TCPOLEN_TSTAMP_APPA; 2138 2139 #ifdef TCP_SIGNATURE 2140 if (tp->t_flags & TF_SIGNATURE) 2141 optlen += TCPOLEN_SIGLEN; 2142 #endif 2143 2144 return optlen; 2145 } 2146 2147 u_int 2148 tcp_hdrsz(struct tcpcb *tp) 2149 { 2150 u_int hlen; 2151 2152 switch (tp->t_family) { 2153 #ifdef INET6 2154 case AF_INET6: 2155 hlen = sizeof(struct ip6_hdr); 2156 break; 2157 #endif 2158 case AF_INET: 2159 hlen = sizeof(struct ip); 2160 break; 2161 default: 2162 hlen = 0; 2163 break; 2164 } 2165 hlen += sizeof(struct tcphdr); 2166 2167 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 2168 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 2169 hlen += TCPOLEN_TSTAMP_APPA; 2170 #ifdef TCP_SIGNATURE 2171 if (tp->t_flags & TF_SIGNATURE) 2172 hlen += TCPOLEN_SIGLEN; 2173 #endif 2174 return hlen; 2175 } 2176 2177 void 2178 tcp_statinc(u_int stat) 2179 { 2180 2181 KASSERT(stat < TCP_NSTATS); 2182 TCP_STATINC(stat); 2183 } 2184 2185 void 2186 tcp_statadd(u_int stat, uint64_t val) 2187 { 2188 2189 KASSERT(stat < TCP_NSTATS); 2190 TCP_STATADD(stat, val); 2191 }
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