tcp_timewait.c revision 167636
1/*- 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 30 * $FreeBSD: head/sys/netinet/tcp_timewait.c 167636 2007-03-16 13:42:26Z rwatson $ 31 */ 32 33#include "opt_compat.h" 34#include "opt_inet.h" 35#include "opt_inet6.h" 36#include "opt_ipsec.h" 37#include "opt_mac.h" 38#include "opt_tcpdebug.h" 39#include "opt_tcp_sack.h" 40 41#include <sys/param.h> 42#include <sys/systm.h> 43#include <sys/callout.h> 44#include <sys/kernel.h> 45#include <sys/sysctl.h> 46#include <sys/malloc.h> 47#include <sys/mbuf.h> 48#ifdef INET6 49#include <sys/domain.h> 50#endif 51#include <sys/priv.h> 52#include <sys/proc.h> 53#include <sys/socket.h> 54#include <sys/socketvar.h> 55#include <sys/protosw.h> 56#include <sys/random.h> 57 58#include <vm/uma.h> 59 60#include <net/route.h> 61#include <net/if.h> 62 63#include <netinet/in.h> 64#include <netinet/in_systm.h> 65#include <netinet/ip.h> 66#ifdef INET6 67#include <netinet/ip6.h> 68#endif 69#include <netinet/in_pcb.h> 70#ifdef INET6 71#include <netinet6/in6_pcb.h> 72#endif 73#include <netinet/in_var.h> 74#include <netinet/ip_var.h> 75#ifdef INET6 76#include <netinet6/ip6_var.h> 77#include <netinet6/scope6_var.h> 78#include <netinet6/nd6.h> 79#endif 80#include <netinet/ip_icmp.h> 81#include <netinet/tcp.h> 82#include <netinet/tcp_fsm.h> 83#include <netinet/tcp_seq.h> 84#include <netinet/tcp_timer.h> 85#include <netinet/tcp_var.h> 86#ifdef INET6 87#include <netinet6/tcp6_var.h> 88#endif 89#include <netinet/tcpip.h> 90#ifdef TCPDEBUG 91#include <netinet/tcp_debug.h> 92#endif 93#include <netinet6/ip6protosw.h> 94 95#ifdef IPSEC 96#include <netinet6/ipsec.h> 97#ifdef INET6 98#include <netinet6/ipsec6.h> 99#endif 100#include <netkey/key.h> 101#endif /*IPSEC*/ 102 103#ifdef FAST_IPSEC 104#include <netipsec/ipsec.h> 105#include <netipsec/xform.h> 106#ifdef INET6 107#include <netipsec/ipsec6.h> 108#endif 109#include <netipsec/key.h> 110#define IPSEC 111#endif /*FAST_IPSEC*/ 112 113#include <machine/in_cksum.h> 114#include <sys/md5.h> 115 116#include <security/mac/mac_framework.h> 117 118int tcp_mssdflt = TCP_MSS; 119SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 120 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size"); 121 122#ifdef INET6 123int tcp_v6mssdflt = TCP6_MSS; 124SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 125 CTLFLAG_RW, &tcp_v6mssdflt , 0, 126 "Default TCP Maximum Segment Size for IPv6"); 127#endif 128 129/* 130 * Minimum MSS we accept and use. This prevents DoS attacks where 131 * we are forced to a ridiculous low MSS like 20 and send hundreds 132 * of packets instead of one. The effect scales with the available 133 * bandwidth and quickly saturates the CPU and network interface 134 * with packet generation and sending. Set to zero to disable MINMSS 135 * checking. This setting prevents us from sending too small packets. 136 */ 137int tcp_minmss = TCP_MINMSS; 138SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 139 &tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 140/* 141 * Number of TCP segments per second we accept from remote host 142 * before we start to calculate average segment size. If average 143 * segment size drops below the minimum TCP MSS we assume a DoS 144 * attack and reset+drop the connection. Care has to be taken not to 145 * set this value too small to not kill interactive type connections 146 * (telnet, SSH) which send many small packets. 147 */ 148int tcp_minmssoverload = TCP_MINMSSOVERLOAD; 149SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmssoverload, CTLFLAG_RW, 150 &tcp_minmssoverload , 0, "Number of TCP Segments per Second allowed to" 151 "be under the MINMSS Size"); 152 153int tcp_do_rfc1323 = 1; 154SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 155 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions"); 156 157static int tcp_tcbhashsize = 0; 158SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 159 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 160 161static int do_tcpdrain = 1; 162SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 163 "Enable tcp_drain routine for extra help when low on mbufs"); 164 165SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 166 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 167 168static int icmp_may_rst = 1; 169SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 170 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 171 172static int tcp_isn_reseed_interval = 0; 173SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 174 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 175 176static uma_zone_t tcptw_zone; 177static int maxtcptw; 178 179static int 180tcptw_auto_size(void) 181{ 182 int halfrange; 183 184 /* 185 * Max out at half the ephemeral port range so that TIME_WAIT 186 * sockets don't tie up too many ephemeral ports. 187 */ 188 if (ipport_lastauto > ipport_firstauto) 189 halfrange = (ipport_lastauto - ipport_firstauto) / 2; 190 else 191 halfrange = (ipport_firstauto - ipport_lastauto) / 2; 192 /* Protect against goofy port ranges smaller than 32. */ 193 return (imin(imax(halfrange, 32), maxsockets / 5)); 194} 195 196static int 197sysctl_maxtcptw(SYSCTL_HANDLER_ARGS) 198{ 199 int error, new; 200 201 if (maxtcptw == 0) 202 new = tcptw_auto_size(); 203 else 204 new = maxtcptw; 205 error = sysctl_handle_int(oidp, &new, sizeof(int), req); 206 if (error == 0 && req->newptr) 207 if (new >= 32) { 208 maxtcptw = new; 209 uma_zone_set_max(tcptw_zone, maxtcptw); 210 } 211 return (error); 212} 213SYSCTL_PROC(_net_inet_tcp, OID_AUTO, maxtcptw, CTLTYPE_INT|CTLFLAG_RW, 214 &maxtcptw, 0, sysctl_maxtcptw, "IU", 215 "Maximum number of compressed TCP TIME_WAIT entries"); 216 217static int nolocaltimewait = 0; 218SYSCTL_INT(_net_inet_tcp, OID_AUTO, nolocaltimewait, CTLFLAG_RW, 219 &nolocaltimewait, 0, "Do not create compressed TCP TIME_WAIT entries" 220 "for local connections"); 221 222/* 223 * TCP bandwidth limiting sysctls. Note that the default lower bound of 224 * 1024 exists only for debugging. A good production default would be 225 * something like 6100. 226 */ 227SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0, 228 "TCP inflight data limiting"); 229 230static int tcp_inflight_enable = 1; 231SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, enable, CTLFLAG_RW, 232 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 233 234static int tcp_inflight_debug = 0; 235SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW, 236 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 237 238static int tcp_inflight_rttthresh; 239SYSCTL_PROC(_net_inet_tcp_inflight, OID_AUTO, rttthresh, CTLTYPE_INT|CTLFLAG_RW, 240 &tcp_inflight_rttthresh, 0, sysctl_msec_to_ticks, "I", 241 "RTT threshold below which inflight will deactivate itself"); 242 243static int tcp_inflight_min = 6144; 244SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, min, CTLFLAG_RW, 245 &tcp_inflight_min, 0, "Lower-bound for TCP inflight window"); 246 247static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 248SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, max, CTLFLAG_RW, 249 &tcp_inflight_max, 0, "Upper-bound for TCP inflight window"); 250 251static int tcp_inflight_stab = 20; 252SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, stab, CTLFLAG_RW, 253 &tcp_inflight_stab, 0, "Inflight Algorithm Stabilization 20 = 2 packets"); 254 255uma_zone_t sack_hole_zone; 256 257static struct inpcb *tcp_notify(struct inpcb *, int); 258static void tcp_isn_tick(void *); 259 260/* 261 * Target size of TCP PCB hash tables. Must be a power of two. 262 * 263 * Note that this can be overridden by the kernel environment 264 * variable net.inet.tcp.tcbhashsize 265 */ 266#ifndef TCBHASHSIZE 267#define TCBHASHSIZE 512 268#endif 269 270/* 271 * XXX 272 * Callouts should be moved into struct tcp directly. They are currently 273 * separate because the tcpcb structure is exported to userland for sysctl 274 * parsing purposes, which do not know about callouts. 275 */ 276struct tcpcb_mem { 277 struct tcpcb tcb; 278 struct callout tcpcb_mem_rexmt, tcpcb_mem_persist, tcpcb_mem_keep; 279 struct callout tcpcb_mem_2msl, tcpcb_mem_delack; 280}; 281 282static uma_zone_t tcpcb_zone; 283struct callout isn_callout; 284static struct mtx isn_mtx; 285 286#define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 287#define ISN_LOCK() mtx_lock(&isn_mtx) 288#define ISN_UNLOCK() mtx_unlock(&isn_mtx) 289 290/* 291 * TCP initialization. 292 */ 293static void 294tcp_zone_change(void *tag) 295{ 296 297 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 298 uma_zone_set_max(tcpcb_zone, maxsockets); 299 if (maxtcptw == 0) 300 uma_zone_set_max(tcptw_zone, tcptw_auto_size()); 301} 302 303static int 304tcp_inpcb_init(void *mem, int size, int flags) 305{ 306 struct inpcb *inp = mem; 307 308 INP_LOCK_INIT(inp, "inp", "tcpinp"); 309 return (0); 310} 311 312void 313tcp_init(void) 314{ 315 int hashsize = TCBHASHSIZE; 316 317 tcp_delacktime = TCPTV_DELACK; 318 tcp_keepinit = TCPTV_KEEP_INIT; 319 tcp_keepidle = TCPTV_KEEP_IDLE; 320 tcp_keepintvl = TCPTV_KEEPINTVL; 321 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 322 tcp_msl = TCPTV_MSL; 323 tcp_rexmit_min = TCPTV_MIN; 324 tcp_rexmit_slop = TCPTV_CPU_VAR; 325 tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 326 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 327 328 INP_INFO_LOCK_INIT(&tcbinfo, "tcp"); 329 LIST_INIT(&tcb); 330 tcbinfo.listhead = &tcb; 331 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 332 if (!powerof2(hashsize)) { 333 printf("WARNING: TCB hash size not a power of 2\n"); 334 hashsize = 512; /* safe default */ 335 } 336 tcp_tcbhashsize = hashsize; 337 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask); 338 tcbinfo.porthashbase = hashinit(hashsize, M_PCB, 339 &tcbinfo.porthashmask); 340 tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb), 341 NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 342 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 343#ifdef INET6 344#define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 345#else /* INET6 */ 346#define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 347#endif /* INET6 */ 348 if (max_protohdr < TCP_MINPROTOHDR) 349 max_protohdr = TCP_MINPROTOHDR; 350 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 351 panic("tcp_init"); 352#undef TCP_MINPROTOHDR 353 /* 354 * These have to be type stable for the benefit of the timers. 355 */ 356 tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 357 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 358 uma_zone_set_max(tcpcb_zone, maxsockets); 359 tcptw_zone = uma_zcreate("tcptw", sizeof(struct tcptw), 360 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 361 TUNABLE_INT_FETCH("net.inet.tcp.maxtcptw", &maxtcptw); 362 if (maxtcptw == 0) 363 uma_zone_set_max(tcptw_zone, tcptw_auto_size()); 364 else 365 uma_zone_set_max(tcptw_zone, maxtcptw); 366 tcp_timer_init(); 367 syncache_init(); 368 tcp_hc_init(); 369 tcp_reass_init(); 370 ISN_LOCK_INIT(); 371 callout_init(&isn_callout, CALLOUT_MPSAFE); 372 tcp_isn_tick(NULL); 373 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 374 SHUTDOWN_PRI_DEFAULT); 375 sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 376 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 377 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 378 EVENTHANDLER_PRI_ANY); 379} 380 381void 382tcp_fini(void *xtp) 383{ 384 385 callout_stop(&isn_callout); 386} 387 388/* 389 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 390 * tcp_template used to store this data in mbufs, but we now recopy it out 391 * of the tcpcb each time to conserve mbufs. 392 */ 393void 394tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 395{ 396 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 397 398 INP_LOCK_ASSERT(inp); 399 400#ifdef INET6 401 if ((inp->inp_vflag & INP_IPV6) != 0) { 402 struct ip6_hdr *ip6; 403 404 ip6 = (struct ip6_hdr *)ip_ptr; 405 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 406 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 407 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 408 (IPV6_VERSION & IPV6_VERSION_MASK); 409 ip6->ip6_nxt = IPPROTO_TCP; 410 ip6->ip6_plen = sizeof(struct tcphdr); 411 ip6->ip6_src = inp->in6p_laddr; 412 ip6->ip6_dst = inp->in6p_faddr; 413 } else 414#endif 415 { 416 struct ip *ip; 417 418 ip = (struct ip *)ip_ptr; 419 ip->ip_v = IPVERSION; 420 ip->ip_hl = 5; 421 ip->ip_tos = inp->inp_ip_tos; 422 ip->ip_len = 0; 423 ip->ip_id = 0; 424 ip->ip_off = 0; 425 ip->ip_ttl = inp->inp_ip_ttl; 426 ip->ip_sum = 0; 427 ip->ip_p = IPPROTO_TCP; 428 ip->ip_src = inp->inp_laddr; 429 ip->ip_dst = inp->inp_faddr; 430 } 431 th->th_sport = inp->inp_lport; 432 th->th_dport = inp->inp_fport; 433 th->th_seq = 0; 434 th->th_ack = 0; 435 th->th_x2 = 0; 436 th->th_off = 5; 437 th->th_flags = 0; 438 th->th_win = 0; 439 th->th_urp = 0; 440 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 441} 442 443/* 444 * Create template to be used to send tcp packets on a connection. 445 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 446 * use for this function is in keepalives, which use tcp_respond. 447 */ 448struct tcptemp * 449tcpip_maketemplate(struct inpcb *inp) 450{ 451 struct mbuf *m; 452 struct tcptemp *n; 453 454 m = m_get(M_DONTWAIT, MT_DATA); 455 if (m == NULL) 456 return (0); 457 m->m_len = sizeof(struct tcptemp); 458 n = mtod(m, struct tcptemp *); 459 460 tcpip_fillheaders(inp, (void *)&n->tt_ipgen, (void *)&n->tt_t); 461 return (n); 462} 463 464/* 465 * Send a single message to the TCP at address specified by 466 * the given TCP/IP header. If m == NULL, then we make a copy 467 * of the tcpiphdr at ti and send directly to the addressed host. 468 * This is used to force keep alive messages out using the TCP 469 * template for a connection. If flags are given then we send 470 * a message back to the TCP which originated the * segment ti, 471 * and discard the mbuf containing it and any other attached mbufs. 472 * 473 * In any case the ack and sequence number of the transmitted 474 * segment are as specified by the parameters. 475 * 476 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 477 */ 478void 479tcp_respond(struct tcpcb *tp, void *ipgen, register struct tcphdr *th, 480 register struct mbuf *m, tcp_seq ack, tcp_seq seq, int flags) 481{ 482 register int tlen; 483 int win = 0; 484 struct ip *ip; 485 struct tcphdr *nth; 486#ifdef INET6 487 struct ip6_hdr *ip6; 488 int isipv6; 489#endif /* INET6 */ 490 int ipflags = 0; 491 struct inpcb *inp; 492 493 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 494 495#ifdef INET6 496 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 497 ip6 = ipgen; 498#endif /* INET6 */ 499 ip = ipgen; 500 501 if (tp != NULL) { 502 inp = tp->t_inpcb; 503 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 504 INP_INFO_WLOCK_ASSERT(&tcbinfo); 505 INP_LOCK_ASSERT(inp); 506 } else 507 inp = NULL; 508 509 if (tp != NULL) { 510 if (!(flags & TH_RST)) { 511 win = sbspace(&inp->inp_socket->so_rcv); 512 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 513 win = (long)TCP_MAXWIN << tp->rcv_scale; 514 } 515 } 516 if (m == NULL) { 517 m = m_gethdr(M_DONTWAIT, MT_DATA); 518 if (m == NULL) 519 return; 520 tlen = 0; 521 m->m_data += max_linkhdr; 522#ifdef INET6 523 if (isipv6) { 524 bcopy((caddr_t)ip6, mtod(m, caddr_t), 525 sizeof(struct ip6_hdr)); 526 ip6 = mtod(m, struct ip6_hdr *); 527 nth = (struct tcphdr *)(ip6 + 1); 528 } else 529#endif /* INET6 */ 530 { 531 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 532 ip = mtod(m, struct ip *); 533 nth = (struct tcphdr *)(ip + 1); 534 } 535 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 536 flags = TH_ACK; 537 } else { 538 m_freem(m->m_next); 539 m->m_next = NULL; 540 m->m_data = (caddr_t)ipgen; 541 /* m_len is set later */ 542 tlen = 0; 543#define xchg(a,b,type) { type t; t=a; a=b; b=t; } 544#ifdef INET6 545 if (isipv6) { 546 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 547 nth = (struct tcphdr *)(ip6 + 1); 548 } else 549#endif /* INET6 */ 550 { 551 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 552 nth = (struct tcphdr *)(ip + 1); 553 } 554 if (th != nth) { 555 /* 556 * this is usually a case when an extension header 557 * exists between the IPv6 header and the 558 * TCP header. 559 */ 560 nth->th_sport = th->th_sport; 561 nth->th_dport = th->th_dport; 562 } 563 xchg(nth->th_dport, nth->th_sport, n_short); 564#undef xchg 565 } 566#ifdef INET6 567 if (isipv6) { 568 ip6->ip6_flow = 0; 569 ip6->ip6_vfc = IPV6_VERSION; 570 ip6->ip6_nxt = IPPROTO_TCP; 571 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 572 tlen)); 573 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 574 } else 575#endif 576 { 577 tlen += sizeof (struct tcpiphdr); 578 ip->ip_len = tlen; 579 ip->ip_ttl = ip_defttl; 580 if (path_mtu_discovery) 581 ip->ip_off |= IP_DF; 582 } 583 m->m_len = tlen; 584 m->m_pkthdr.len = tlen; 585 m->m_pkthdr.rcvif = NULL; 586#ifdef MAC 587 if (inp != NULL) { 588 /* 589 * Packet is associated with a socket, so allow the 590 * label of the response to reflect the socket label. 591 */ 592 INP_LOCK_ASSERT(inp); 593 mac_create_mbuf_from_inpcb(inp, m); 594 } else { 595 /* 596 * Packet is not associated with a socket, so possibly 597 * update the label in place. 598 */ 599 mac_reflect_mbuf_tcp(m); 600 } 601#endif 602 nth->th_seq = htonl(seq); 603 nth->th_ack = htonl(ack); 604 nth->th_x2 = 0; 605 nth->th_off = sizeof (struct tcphdr) >> 2; 606 nth->th_flags = flags; 607 if (tp != NULL) 608 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 609 else 610 nth->th_win = htons((u_short)win); 611 nth->th_urp = 0; 612#ifdef INET6 613 if (isipv6) { 614 nth->th_sum = 0; 615 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 616 sizeof(struct ip6_hdr), 617 tlen - sizeof(struct ip6_hdr)); 618 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 619 NULL, NULL); 620 } else 621#endif /* INET6 */ 622 { 623 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 624 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 625 m->m_pkthdr.csum_flags = CSUM_TCP; 626 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 627 } 628#ifdef TCPDEBUG 629 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 630 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 631#endif 632#ifdef INET6 633 if (isipv6) 634 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 635 else 636#endif /* INET6 */ 637 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 638} 639 640/* 641 * Create a new TCP control block, making an 642 * empty reassembly queue and hooking it to the argument 643 * protocol control block. The `inp' parameter must have 644 * come from the zone allocator set up in tcp_init(). 645 */ 646struct tcpcb * 647tcp_newtcpcb(struct inpcb *inp) 648{ 649 struct tcpcb_mem *tm; 650 struct tcpcb *tp; 651#ifdef INET6 652 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 653#endif /* INET6 */ 654 655 tm = uma_zalloc(tcpcb_zone, M_NOWAIT | M_ZERO); 656 if (tm == NULL) 657 return (NULL); 658 tp = &tm->tcb; 659 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 660 tp->t_maxseg = tp->t_maxopd = 661#ifdef INET6 662 isipv6 ? tcp_v6mssdflt : 663#endif /* INET6 */ 664 tcp_mssdflt; 665 666 /* Set up our timeouts. */ 667 callout_init(tp->tt_rexmt = &tm->tcpcb_mem_rexmt, NET_CALLOUT_MPSAFE); 668 callout_init(tp->tt_persist = &tm->tcpcb_mem_persist, NET_CALLOUT_MPSAFE); 669 callout_init(tp->tt_keep = &tm->tcpcb_mem_keep, NET_CALLOUT_MPSAFE); 670 callout_init(tp->tt_2msl = &tm->tcpcb_mem_2msl, NET_CALLOUT_MPSAFE); 671 callout_init(tp->tt_delack = &tm->tcpcb_mem_delack, NET_CALLOUT_MPSAFE); 672 673 if (tcp_do_rfc1323) 674 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 675 tp->sack_enable = tcp_do_sack; 676 TAILQ_INIT(&tp->snd_holes); 677 tp->t_inpcb = inp; /* XXX */ 678 /* 679 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 680 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 681 * reasonable initial retransmit time. 682 */ 683 tp->t_srtt = TCPTV_SRTTBASE; 684 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 685 tp->t_rttmin = tcp_rexmit_min; 686 tp->t_rxtcur = TCPTV_RTOBASE; 687 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 688 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 689 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 690 tp->t_rcvtime = ticks; 691 tp->t_bw_rtttime = ticks; 692 /* 693 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 694 * because the socket may be bound to an IPv6 wildcard address, 695 * which may match an IPv4-mapped IPv6 address. 696 */ 697 inp->inp_ip_ttl = ip_defttl; 698 inp->inp_ppcb = tp; 699 return (tp); /* XXX */ 700} 701 702/* 703 * Drop a TCP connection, reporting 704 * the specified error. If connection is synchronized, 705 * then send a RST to peer. 706 */ 707struct tcpcb * 708tcp_drop(struct tcpcb *tp, int errno) 709{ 710 struct socket *so = tp->t_inpcb->inp_socket; 711 712 INP_INFO_WLOCK_ASSERT(&tcbinfo); 713 INP_LOCK_ASSERT(tp->t_inpcb); 714 715 if (TCPS_HAVERCVDSYN(tp->t_state)) { 716 tp->t_state = TCPS_CLOSED; 717 (void) tcp_output(tp); 718 tcpstat.tcps_drops++; 719 } else 720 tcpstat.tcps_conndrops++; 721 if (errno == ETIMEDOUT && tp->t_softerror) 722 errno = tp->t_softerror; 723 so->so_error = errno; 724 return (tcp_close(tp)); 725} 726 727void 728tcp_discardcb(struct tcpcb *tp) 729{ 730 struct tseg_qent *q; 731 struct inpcb *inp = tp->t_inpcb; 732 struct socket *so = inp->inp_socket; 733#ifdef INET6 734 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 735#endif /* INET6 */ 736 737 INP_LOCK_ASSERT(inp); 738 739 /* 740 * Make sure that all of our timers are stopped before we 741 * delete the PCB. 742 */ 743 callout_stop(tp->tt_rexmt); 744 callout_stop(tp->tt_persist); 745 callout_stop(tp->tt_keep); 746 callout_stop(tp->tt_2msl); 747 callout_stop(tp->tt_delack); 748 749 /* 750 * If we got enough samples through the srtt filter, 751 * save the rtt and rttvar in the routing entry. 752 * 'Enough' is arbitrarily defined as 4 rtt samples. 753 * 4 samples is enough for the srtt filter to converge 754 * to within enough % of the correct value; fewer samples 755 * and we could save a bogus rtt. The danger is not high 756 * as tcp quickly recovers from everything. 757 * XXX: Works very well but needs some more statistics! 758 */ 759 if (tp->t_rttupdated >= 4) { 760 struct hc_metrics_lite metrics; 761 u_long ssthresh; 762 763 bzero(&metrics, sizeof(metrics)); 764 /* 765 * Update the ssthresh always when the conditions below 766 * are satisfied. This gives us better new start value 767 * for the congestion avoidance for new connections. 768 * ssthresh is only set if packet loss occured on a session. 769 * 770 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 771 * being torn down. Ideally this code would not use 'so'. 772 */ 773 ssthresh = tp->snd_ssthresh; 774 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 775 /* 776 * convert the limit from user data bytes to 777 * packets then to packet data bytes. 778 */ 779 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 780 if (ssthresh < 2) 781 ssthresh = 2; 782 ssthresh *= (u_long)(tp->t_maxseg + 783#ifdef INET6 784 (isipv6 ? sizeof (struct ip6_hdr) + 785 sizeof (struct tcphdr) : 786#endif 787 sizeof (struct tcpiphdr) 788#ifdef INET6 789 ) 790#endif 791 ); 792 } else 793 ssthresh = 0; 794 metrics.rmx_ssthresh = ssthresh; 795 796 metrics.rmx_rtt = tp->t_srtt; 797 metrics.rmx_rttvar = tp->t_rttvar; 798 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 799 metrics.rmx_bandwidth = tp->snd_bandwidth; 800 metrics.rmx_cwnd = tp->snd_cwnd; 801 metrics.rmx_sendpipe = 0; 802 metrics.rmx_recvpipe = 0; 803 804 tcp_hc_update(&inp->inp_inc, &metrics); 805 } 806 807 /* free the reassembly queue, if any */ 808 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) { 809 LIST_REMOVE(q, tqe_q); 810 m_freem(q->tqe_m); 811 uma_zfree(tcp_reass_zone, q); 812 tp->t_segqlen--; 813 tcp_reass_qsize--; 814 } 815 tcp_free_sackholes(tp); 816 inp->inp_ppcb = NULL; 817 tp->t_inpcb = NULL; 818 uma_zfree(tcpcb_zone, tp); 819} 820 821/* 822 * Attempt to close a TCP control block, marking it as dropped, and freeing 823 * the socket if we hold the only reference. 824 */ 825struct tcpcb * 826tcp_close(struct tcpcb *tp) 827{ 828 struct inpcb *inp = tp->t_inpcb; 829 struct socket *so; 830 831 INP_INFO_WLOCK_ASSERT(&tcbinfo); 832 INP_LOCK_ASSERT(inp); 833 834 in_pcbdrop(inp); 835 tcpstat.tcps_closed++; 836 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 837 so = inp->inp_socket; 838 soisdisconnected(so); 839 if (inp->inp_vflag & INP_SOCKREF) { 840 KASSERT(so->so_state & SS_PROTOREF, 841 ("tcp_close: !SS_PROTOREF")); 842 inp->inp_vflag &= ~INP_SOCKREF; 843 INP_UNLOCK(inp); 844 ACCEPT_LOCK(); 845 SOCK_LOCK(so); 846 so->so_state &= ~SS_PROTOREF; 847 sofree(so); 848 return (NULL); 849 } 850 return (tp); 851} 852 853void 854tcp_drain(void) 855{ 856 857 if (do_tcpdrain) { 858 struct inpcb *inpb; 859 struct tcpcb *tcpb; 860 struct tseg_qent *te; 861 862 /* 863 * Walk the tcpbs, if existing, and flush the reassembly queue, 864 * if there is one... 865 * XXX: The "Net/3" implementation doesn't imply that the TCP 866 * reassembly queue should be flushed, but in a situation 867 * where we're really low on mbufs, this is potentially 868 * usefull. 869 */ 870 INP_INFO_RLOCK(&tcbinfo); 871 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) { 872 if (inpb->inp_vflag & INP_TIMEWAIT) 873 continue; 874 INP_LOCK(inpb); 875 if ((tcpb = intotcpcb(inpb)) != NULL) { 876 while ((te = LIST_FIRST(&tcpb->t_segq)) 877 != NULL) { 878 LIST_REMOVE(te, tqe_q); 879 m_freem(te->tqe_m); 880 uma_zfree(tcp_reass_zone, te); 881 tcpb->t_segqlen--; 882 tcp_reass_qsize--; 883 } 884 tcp_clean_sackreport(tcpb); 885 } 886 INP_UNLOCK(inpb); 887 } 888 INP_INFO_RUNLOCK(&tcbinfo); 889 } 890} 891 892/* 893 * Notify a tcp user of an asynchronous error; 894 * store error as soft error, but wake up user 895 * (for now, won't do anything until can select for soft error). 896 * 897 * Do not wake up user since there currently is no mechanism for 898 * reporting soft errors (yet - a kqueue filter may be added). 899 */ 900static struct inpcb * 901tcp_notify(struct inpcb *inp, int error) 902{ 903 struct tcpcb *tp; 904 905 INP_INFO_WLOCK_ASSERT(&tcbinfo); 906 INP_LOCK_ASSERT(inp); 907 908 if ((inp->inp_vflag & INP_TIMEWAIT) || 909 (inp->inp_vflag & INP_DROPPED)) 910 return (inp); 911 912 tp = intotcpcb(inp); 913 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 914 915 /* 916 * Ignore some errors if we are hooked up. 917 * If connection hasn't completed, has retransmitted several times, 918 * and receives a second error, give up now. This is better 919 * than waiting a long time to establish a connection that 920 * can never complete. 921 */ 922 if (tp->t_state == TCPS_ESTABLISHED && 923 (error == EHOSTUNREACH || error == ENETUNREACH || 924 error == EHOSTDOWN)) { 925 return (inp); 926 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 927 tp->t_softerror) { 928 tp = tcp_drop(tp, error); 929 if (tp != NULL) 930 return (inp); 931 else 932 return (NULL); 933 } else { 934 tp->t_softerror = error; 935 return (inp); 936 } 937#if 0 938 wakeup( &so->so_timeo); 939 sorwakeup(so); 940 sowwakeup(so); 941#endif 942} 943 944static int 945tcp_pcblist(SYSCTL_HANDLER_ARGS) 946{ 947 int error, i, n; 948 struct inpcb *inp, **inp_list; 949 inp_gen_t gencnt; 950 struct xinpgen xig; 951 952 /* 953 * The process of preparing the TCB list is too time-consuming and 954 * resource-intensive to repeat twice on every request. 955 */ 956 if (req->oldptr == NULL) { 957 n = tcbinfo.ipi_count; 958 req->oldidx = 2 * (sizeof xig) 959 + (n + n/8) * sizeof(struct xtcpcb); 960 return (0); 961 } 962 963 if (req->newptr != NULL) 964 return (EPERM); 965 966 /* 967 * OK, now we're committed to doing something. 968 */ 969 INP_INFO_RLOCK(&tcbinfo); 970 gencnt = tcbinfo.ipi_gencnt; 971 n = tcbinfo.ipi_count; 972 INP_INFO_RUNLOCK(&tcbinfo); 973 974 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 975 + n * sizeof(struct xtcpcb)); 976 if (error != 0) 977 return (error); 978 979 xig.xig_len = sizeof xig; 980 xig.xig_count = n; 981 xig.xig_gen = gencnt; 982 xig.xig_sogen = so_gencnt; 983 error = SYSCTL_OUT(req, &xig, sizeof xig); 984 if (error) 985 return (error); 986 987 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 988 if (inp_list == NULL) 989 return (ENOMEM); 990 991 INP_INFO_RLOCK(&tcbinfo); 992 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp != NULL && i < n; 993 inp = LIST_NEXT(inp, inp_list)) { 994 INP_LOCK(inp); 995 if (inp->inp_gencnt <= gencnt) { 996 /* 997 * XXX: This use of cr_cansee(), introduced with 998 * TCP state changes, is not quite right, but for 999 * now, better than nothing. 1000 */ 1001 if (inp->inp_vflag & INP_TIMEWAIT) { 1002 if (intotw(inp) != NULL) 1003 error = cr_cansee(req->td->td_ucred, 1004 intotw(inp)->tw_cred); 1005 else 1006 error = EINVAL; /* Skip this inp. */ 1007 } else 1008 error = cr_canseesocket(req->td->td_ucred, 1009 inp->inp_socket); 1010 if (error == 0) 1011 inp_list[i++] = inp; 1012 } 1013 INP_UNLOCK(inp); 1014 } 1015 INP_INFO_RUNLOCK(&tcbinfo); 1016 n = i; 1017 1018 error = 0; 1019 for (i = 0; i < n; i++) { 1020 inp = inp_list[i]; 1021 INP_LOCK(inp); 1022 if (inp->inp_gencnt <= gencnt) { 1023 struct xtcpcb xt; 1024 void *inp_ppcb; 1025 1026 bzero(&xt, sizeof(xt)); 1027 xt.xt_len = sizeof xt; 1028 /* XXX should avoid extra copy */ 1029 bcopy(inp, &xt.xt_inp, sizeof *inp); 1030 inp_ppcb = inp->inp_ppcb; 1031 if (inp_ppcb == NULL) 1032 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1033 else if (inp->inp_vflag & INP_TIMEWAIT) { 1034 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1035 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1036 } else 1037 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1038 if (inp->inp_socket != NULL) 1039 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1040 else { 1041 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1042 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1043 } 1044 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1045 INP_UNLOCK(inp); 1046 error = SYSCTL_OUT(req, &xt, sizeof xt); 1047 } else 1048 INP_UNLOCK(inp); 1049 1050 } 1051 if (!error) { 1052 /* 1053 * Give the user an updated idea of our state. 1054 * If the generation differs from what we told 1055 * her before, she knows that something happened 1056 * while we were processing this request, and it 1057 * might be necessary to retry. 1058 */ 1059 INP_INFO_RLOCK(&tcbinfo); 1060 xig.xig_gen = tcbinfo.ipi_gencnt; 1061 xig.xig_sogen = so_gencnt; 1062 xig.xig_count = tcbinfo.ipi_count; 1063 INP_INFO_RUNLOCK(&tcbinfo); 1064 error = SYSCTL_OUT(req, &xig, sizeof xig); 1065 } 1066 free(inp_list, M_TEMP); 1067 return (error); 1068} 1069 1070SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1071 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1072 1073static int 1074tcp_getcred(SYSCTL_HANDLER_ARGS) 1075{ 1076 struct xucred xuc; 1077 struct sockaddr_in addrs[2]; 1078 struct inpcb *inp; 1079 int error; 1080 1081 error = priv_check_cred(req->td->td_ucred, PRIV_NETINET_GETCRED, 1082 SUSER_ALLOWJAIL); 1083 if (error) 1084 return (error); 1085 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1086 if (error) 1087 return (error); 1088 INP_INFO_RLOCK(&tcbinfo); 1089 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 1090 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1091 if (inp == NULL) { 1092 error = ENOENT; 1093 goto outunlocked; 1094 } 1095 INP_LOCK(inp); 1096 if (inp->inp_socket == NULL) { 1097 error = ENOENT; 1098 goto out; 1099 } 1100 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1101 if (error) 1102 goto out; 1103 cru2x(inp->inp_socket->so_cred, &xuc); 1104out: 1105 INP_UNLOCK(inp); 1106outunlocked: 1107 INP_INFO_RUNLOCK(&tcbinfo); 1108 if (error == 0) 1109 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1110 return (error); 1111} 1112 1113SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1114 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1115 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1116 1117#ifdef INET6 1118static int 1119tcp6_getcred(SYSCTL_HANDLER_ARGS) 1120{ 1121 struct xucred xuc; 1122 struct sockaddr_in6 addrs[2]; 1123 struct inpcb *inp; 1124 int error, mapped = 0; 1125 1126 error = priv_check_cred(req->td->td_ucred, PRIV_NETINET_GETCRED, 1127 SUSER_ALLOWJAIL); 1128 if (error) 1129 return (error); 1130 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1131 if (error) 1132 return (error); 1133 if ((error = sa6_embedscope(&addrs[0], ip6_use_defzone)) != 0 || 1134 (error = sa6_embedscope(&addrs[1], ip6_use_defzone)) != 0) { 1135 return (error); 1136 } 1137 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1138 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1139 mapped = 1; 1140 else 1141 return (EINVAL); 1142 } 1143 1144 INP_INFO_RLOCK(&tcbinfo); 1145 if (mapped == 1) 1146 inp = in_pcblookup_hash(&tcbinfo, 1147 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1148 addrs[1].sin6_port, 1149 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1150 addrs[0].sin6_port, 1151 0, NULL); 1152 else 1153 inp = in6_pcblookup_hash(&tcbinfo, 1154 &addrs[1].sin6_addr, addrs[1].sin6_port, 1155 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1156 if (inp == NULL) { 1157 error = ENOENT; 1158 goto outunlocked; 1159 } 1160 INP_LOCK(inp); 1161 if (inp->inp_socket == NULL) { 1162 error = ENOENT; 1163 goto out; 1164 } 1165 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1166 if (error) 1167 goto out; 1168 cru2x(inp->inp_socket->so_cred, &xuc); 1169out: 1170 INP_UNLOCK(inp); 1171outunlocked: 1172 INP_INFO_RUNLOCK(&tcbinfo); 1173 if (error == 0) 1174 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1175 return (error); 1176} 1177 1178SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1179 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1180 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1181#endif 1182 1183 1184void 1185tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1186{ 1187 struct ip *ip = vip; 1188 struct tcphdr *th; 1189 struct in_addr faddr; 1190 struct inpcb *inp; 1191 struct tcpcb *tp; 1192 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1193 struct icmp *icp; 1194 struct in_conninfo inc; 1195 tcp_seq icmp_tcp_seq; 1196 int mtu; 1197 1198 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1199 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1200 return; 1201 1202 if (cmd == PRC_MSGSIZE) 1203 notify = tcp_mtudisc; 1204 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1205 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1206 notify = tcp_drop_syn_sent; 1207 /* 1208 * Redirects don't need to be handled up here. 1209 */ 1210 else if (PRC_IS_REDIRECT(cmd)) 1211 return; 1212 /* 1213 * Source quench is depreciated. 1214 */ 1215 else if (cmd == PRC_QUENCH) 1216 return; 1217 /* 1218 * Hostdead is ugly because it goes linearly through all PCBs. 1219 * XXX: We never get this from ICMP, otherwise it makes an 1220 * excellent DoS attack on machines with many connections. 1221 */ 1222 else if (cmd == PRC_HOSTDEAD) 1223 ip = NULL; 1224 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1225 return; 1226 if (ip != NULL) { 1227 icp = (struct icmp *)((caddr_t)ip 1228 - offsetof(struct icmp, icmp_ip)); 1229 th = (struct tcphdr *)((caddr_t)ip 1230 + (ip->ip_hl << 2)); 1231 INP_INFO_WLOCK(&tcbinfo); 1232 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1233 ip->ip_src, th->th_sport, 0, NULL); 1234 if (inp != NULL) { 1235 INP_LOCK(inp); 1236 if (!(inp->inp_vflag & INP_TIMEWAIT) && 1237 !(inp->inp_vflag & INP_DROPPED) && 1238 !(inp->inp_socket == NULL)) { 1239 icmp_tcp_seq = htonl(th->th_seq); 1240 tp = intotcpcb(inp); 1241 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1242 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1243 if (cmd == PRC_MSGSIZE) { 1244 /* 1245 * MTU discovery: 1246 * If we got a needfrag set the MTU 1247 * in the route to the suggested new 1248 * value (if given) and then notify. 1249 */ 1250 bzero(&inc, sizeof(inc)); 1251 inc.inc_flags = 0; /* IPv4 */ 1252 inc.inc_faddr = faddr; 1253 1254 mtu = ntohs(icp->icmp_nextmtu); 1255 /* 1256 * If no alternative MTU was 1257 * proposed, try the next smaller 1258 * one. ip->ip_len has already 1259 * been swapped in icmp_input(). 1260 */ 1261 if (!mtu) 1262 mtu = ip_next_mtu(ip->ip_len, 1263 1); 1264 if (mtu < max(296, (tcp_minmss) 1265 + sizeof(struct tcpiphdr))) 1266 mtu = 0; 1267 if (!mtu) 1268 mtu = tcp_mssdflt 1269 + sizeof(struct tcpiphdr); 1270 /* 1271 * Only cache the the MTU if it 1272 * is smaller than the interface 1273 * or route MTU. tcp_mtudisc() 1274 * will do right thing by itself. 1275 */ 1276 if (mtu <= tcp_maxmtu(&inc, NULL)) 1277 tcp_hc_updatemtu(&inc, mtu); 1278 } 1279 1280 inp = (*notify)(inp, inetctlerrmap[cmd]); 1281 } 1282 } 1283 if (inp != NULL) 1284 INP_UNLOCK(inp); 1285 } else { 1286 inc.inc_fport = th->th_dport; 1287 inc.inc_lport = th->th_sport; 1288 inc.inc_faddr = faddr; 1289 inc.inc_laddr = ip->ip_src; 1290#ifdef INET6 1291 inc.inc_isipv6 = 0; 1292#endif 1293 syncache_unreach(&inc, th); 1294 } 1295 INP_INFO_WUNLOCK(&tcbinfo); 1296 } else 1297 in_pcbnotifyall(&tcbinfo, faddr, inetctlerrmap[cmd], notify); 1298} 1299 1300#ifdef INET6 1301void 1302tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1303{ 1304 struct tcphdr th; 1305 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1306 struct ip6_hdr *ip6; 1307 struct mbuf *m; 1308 struct ip6ctlparam *ip6cp = NULL; 1309 const struct sockaddr_in6 *sa6_src = NULL; 1310 int off; 1311 struct tcp_portonly { 1312 u_int16_t th_sport; 1313 u_int16_t th_dport; 1314 } *thp; 1315 1316 if (sa->sa_family != AF_INET6 || 1317 sa->sa_len != sizeof(struct sockaddr_in6)) 1318 return; 1319 1320 if (cmd == PRC_MSGSIZE) 1321 notify = tcp_mtudisc; 1322 else if (!PRC_IS_REDIRECT(cmd) && 1323 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1324 return; 1325 /* Source quench is depreciated. */ 1326 else if (cmd == PRC_QUENCH) 1327 return; 1328 1329 /* if the parameter is from icmp6, decode it. */ 1330 if (d != NULL) { 1331 ip6cp = (struct ip6ctlparam *)d; 1332 m = ip6cp->ip6c_m; 1333 ip6 = ip6cp->ip6c_ip6; 1334 off = ip6cp->ip6c_off; 1335 sa6_src = ip6cp->ip6c_src; 1336 } else { 1337 m = NULL; 1338 ip6 = NULL; 1339 off = 0; /* fool gcc */ 1340 sa6_src = &sa6_any; 1341 } 1342 1343 if (ip6 != NULL) { 1344 struct in_conninfo inc; 1345 /* 1346 * XXX: We assume that when IPV6 is non NULL, 1347 * M and OFF are valid. 1348 */ 1349 1350 /* check if we can safely examine src and dst ports */ 1351 if (m->m_pkthdr.len < off + sizeof(*thp)) 1352 return; 1353 1354 bzero(&th, sizeof(th)); 1355 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1356 1357 in6_pcbnotify(&tcbinfo, sa, th.th_dport, 1358 (struct sockaddr *)ip6cp->ip6c_src, 1359 th.th_sport, cmd, NULL, notify); 1360 1361 inc.inc_fport = th.th_dport; 1362 inc.inc_lport = th.th_sport; 1363 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1364 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1365 inc.inc_isipv6 = 1; 1366 INP_INFO_WLOCK(&tcbinfo); 1367 syncache_unreach(&inc, &th); 1368 INP_INFO_WUNLOCK(&tcbinfo); 1369 } else 1370 in6_pcbnotify(&tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1371 0, cmd, NULL, notify); 1372} 1373#endif /* INET6 */ 1374 1375 1376/* 1377 * Following is where TCP initial sequence number generation occurs. 1378 * 1379 * There are two places where we must use initial sequence numbers: 1380 * 1. In SYN-ACK packets. 1381 * 2. In SYN packets. 1382 * 1383 * All ISNs for SYN-ACK packets are generated by the syncache. See 1384 * tcp_syncache.c for details. 1385 * 1386 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1387 * depends on this property. In addition, these ISNs should be 1388 * unguessable so as to prevent connection hijacking. To satisfy 1389 * the requirements of this situation, the algorithm outlined in 1390 * RFC 1948 is used, with only small modifications. 1391 * 1392 * Implementation details: 1393 * 1394 * Time is based off the system timer, and is corrected so that it 1395 * increases by one megabyte per second. This allows for proper 1396 * recycling on high speed LANs while still leaving over an hour 1397 * before rollover. 1398 * 1399 * As reading the *exact* system time is too expensive to be done 1400 * whenever setting up a TCP connection, we increment the time 1401 * offset in two ways. First, a small random positive increment 1402 * is added to isn_offset for each connection that is set up. 1403 * Second, the function tcp_isn_tick fires once per clock tick 1404 * and increments isn_offset as necessary so that sequence numbers 1405 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1406 * random positive increments serve only to ensure that the same 1407 * exact sequence number is never sent out twice (as could otherwise 1408 * happen when a port is recycled in less than the system tick 1409 * interval.) 1410 * 1411 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1412 * between seeding of isn_secret. This is normally set to zero, 1413 * as reseeding should not be necessary. 1414 * 1415 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1416 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1417 * general, this means holding an exclusive (write) lock. 1418 */ 1419 1420#define ISN_BYTES_PER_SECOND 1048576 1421#define ISN_STATIC_INCREMENT 4096 1422#define ISN_RANDOM_INCREMENT (4096 - 1) 1423 1424static u_char isn_secret[32]; 1425static int isn_last_reseed; 1426static u_int32_t isn_offset, isn_offset_old; 1427static MD5_CTX isn_ctx; 1428 1429tcp_seq 1430tcp_new_isn(struct tcpcb *tp) 1431{ 1432 u_int32_t md5_buffer[4]; 1433 tcp_seq new_isn; 1434 1435 INP_LOCK_ASSERT(tp->t_inpcb); 1436 1437 ISN_LOCK(); 1438 /* Seed if this is the first use, reseed if requested. */ 1439 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1440 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1441 < (u_int)ticks))) { 1442 read_random(&isn_secret, sizeof(isn_secret)); 1443 isn_last_reseed = ticks; 1444 } 1445 1446 /* Compute the md5 hash and return the ISN. */ 1447 MD5Init(&isn_ctx); 1448 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1449 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1450#ifdef INET6 1451 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1452 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1453 sizeof(struct in6_addr)); 1454 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1455 sizeof(struct in6_addr)); 1456 } else 1457#endif 1458 { 1459 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1460 sizeof(struct in_addr)); 1461 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1462 sizeof(struct in_addr)); 1463 } 1464 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1465 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1466 new_isn = (tcp_seq) md5_buffer[0]; 1467 isn_offset += ISN_STATIC_INCREMENT + 1468 (arc4random() & ISN_RANDOM_INCREMENT); 1469 new_isn += isn_offset; 1470 ISN_UNLOCK(); 1471 return (new_isn); 1472} 1473 1474/* 1475 * Increment the offset to the next ISN_BYTES_PER_SECOND / hz boundary 1476 * to keep time flowing at a relatively constant rate. If the random 1477 * increments have already pushed us past the projected offset, do nothing. 1478 */ 1479static void 1480tcp_isn_tick(void *xtp) 1481{ 1482 u_int32_t projected_offset; 1483 1484 ISN_LOCK(); 1485 projected_offset = isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1486 1487 if (projected_offset > isn_offset) 1488 isn_offset = projected_offset; 1489 1490 isn_offset_old = isn_offset; 1491 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1492 ISN_UNLOCK(); 1493} 1494 1495/* 1496 * When a specific ICMP unreachable message is received and the 1497 * connection state is SYN-SENT, drop the connection. This behavior 1498 * is controlled by the icmp_may_rst sysctl. 1499 */ 1500struct inpcb * 1501tcp_drop_syn_sent(struct inpcb *inp, int errno) 1502{ 1503 struct tcpcb *tp; 1504 1505 INP_INFO_WLOCK_ASSERT(&tcbinfo); 1506 INP_LOCK_ASSERT(inp); 1507 1508 if ((inp->inp_vflag & INP_TIMEWAIT) || 1509 (inp->inp_vflag & INP_DROPPED)) 1510 return (inp); 1511 1512 tp = intotcpcb(inp); 1513 if (tp->t_state != TCPS_SYN_SENT) 1514 return (inp); 1515 1516 tp = tcp_drop(tp, errno); 1517 if (tp != NULL) 1518 return (inp); 1519 else 1520 return (NULL); 1521} 1522 1523/* 1524 * When `need fragmentation' ICMP is received, update our idea of the MSS 1525 * based on the new value in the route. Also nudge TCP to send something, 1526 * since we know the packet we just sent was dropped. 1527 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1528 */ 1529struct inpcb * 1530tcp_mtudisc(struct inpcb *inp, int errno) 1531{ 1532 struct tcpcb *tp; 1533 struct socket *so = inp->inp_socket; 1534 u_int maxmtu; 1535 u_int romtu; 1536 int mss; 1537#ifdef INET6 1538 int isipv6; 1539#endif /* INET6 */ 1540 1541 INP_LOCK_ASSERT(inp); 1542 if ((inp->inp_vflag & INP_TIMEWAIT) || 1543 (inp->inp_vflag & INP_DROPPED)) 1544 return (inp); 1545 1546 tp = intotcpcb(inp); 1547 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1548 1549#ifdef INET6 1550 isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1551#endif 1552 maxmtu = tcp_hc_getmtu(&inp->inp_inc); /* IPv4 and IPv6 */ 1553 romtu = 1554#ifdef INET6 1555 isipv6 ? tcp_maxmtu6(&inp->inp_inc, NULL) : 1556#endif /* INET6 */ 1557 tcp_maxmtu(&inp->inp_inc, NULL); 1558 if (!maxmtu) 1559 maxmtu = romtu; 1560 else 1561 maxmtu = min(maxmtu, romtu); 1562 if (!maxmtu) { 1563 tp->t_maxopd = tp->t_maxseg = 1564#ifdef INET6 1565 isipv6 ? tcp_v6mssdflt : 1566#endif /* INET6 */ 1567 tcp_mssdflt; 1568 return (inp); 1569 } 1570 mss = maxmtu - 1571#ifdef INET6 1572 (isipv6 ? sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1573#endif /* INET6 */ 1574 sizeof(struct tcpiphdr) 1575#ifdef INET6 1576 ) 1577#endif /* INET6 */ 1578 ; 1579 1580 /* 1581 * XXX - The above conditional probably violates the TCP 1582 * spec. The problem is that, since we don't know the 1583 * other end's MSS, we are supposed to use a conservative 1584 * default. But, if we do that, then MTU discovery will 1585 * never actually take place, because the conservative 1586 * default is much less than the MTUs typically seen 1587 * on the Internet today. For the moment, we'll sweep 1588 * this under the carpet. 1589 * 1590 * The conservative default might not actually be a problem 1591 * if the only case this occurs is when sending an initial 1592 * SYN with options and data to a host we've never talked 1593 * to before. Then, they will reply with an MSS value which 1594 * will get recorded and the new parameters should get 1595 * recomputed. For Further Study. 1596 */ 1597 if (tp->t_maxopd <= mss) 1598 return (inp); 1599 tp->t_maxopd = mss; 1600 1601 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1602 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1603 mss -= TCPOLEN_TSTAMP_APPA; 1604#if (MCLBYTES & (MCLBYTES - 1)) == 0 1605 if (mss > MCLBYTES) 1606 mss &= ~(MCLBYTES-1); 1607#else 1608 if (mss > MCLBYTES) 1609 mss = mss / MCLBYTES * MCLBYTES; 1610#endif 1611 if (so->so_snd.sb_hiwat < mss) 1612 mss = so->so_snd.sb_hiwat; 1613 1614 tp->t_maxseg = mss; 1615 1616 tcpstat.tcps_mturesent++; 1617 tp->t_rtttime = 0; 1618 tp->snd_nxt = tp->snd_una; 1619 tcp_free_sackholes(tp); 1620 tp->snd_recover = tp->snd_max; 1621 if (tp->sack_enable) 1622 EXIT_FASTRECOVERY(tp); 1623 tcp_output(tp); 1624 return (inp); 1625} 1626 1627/* 1628 * Look-up the routing entry to the peer of this inpcb. If no route 1629 * is found and it cannot be allocated, then return NULL. This routine 1630 * is called by TCP routines that access the rmx structure and by tcp_mss 1631 * to get the interface MTU. 1632 */ 1633u_long 1634tcp_maxmtu(struct in_conninfo *inc, int *flags) 1635{ 1636 struct route sro; 1637 struct sockaddr_in *dst; 1638 struct ifnet *ifp; 1639 u_long maxmtu = 0; 1640 1641 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1642 1643 bzero(&sro, sizeof(sro)); 1644 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1645 dst = (struct sockaddr_in *)&sro.ro_dst; 1646 dst->sin_family = AF_INET; 1647 dst->sin_len = sizeof(*dst); 1648 dst->sin_addr = inc->inc_faddr; 1649 rtalloc_ign(&sro, RTF_CLONING); 1650 } 1651 if (sro.ro_rt != NULL) { 1652 ifp = sro.ro_rt->rt_ifp; 1653 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1654 maxmtu = ifp->if_mtu; 1655 else 1656 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1657 1658 /* Report additional interface capabilities. */ 1659 if (flags != NULL) { 1660 if (ifp->if_capenable & IFCAP_TSO4 && 1661 ifp->if_hwassist & CSUM_TSO) 1662 *flags |= CSUM_TSO; 1663 } 1664 RTFREE(sro.ro_rt); 1665 } 1666 return (maxmtu); 1667} 1668 1669#ifdef INET6 1670u_long 1671tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1672{ 1673 struct route_in6 sro6; 1674 struct ifnet *ifp; 1675 u_long maxmtu = 0; 1676 1677 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1678 1679 bzero(&sro6, sizeof(sro6)); 1680 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1681 sro6.ro_dst.sin6_family = AF_INET6; 1682 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1683 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1684 rtalloc_ign((struct route *)&sro6, RTF_CLONING); 1685 } 1686 if (sro6.ro_rt != NULL) { 1687 ifp = sro6.ro_rt->rt_ifp; 1688 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1689 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1690 else 1691 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1692 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1693 1694 /* Report additional interface capabilities. */ 1695 if (flags != NULL) { 1696 if (ifp->if_capenable & IFCAP_TSO6 && 1697 ifp->if_hwassist & CSUM_TSO) 1698 *flags |= CSUM_TSO; 1699 } 1700 RTFREE(sro6.ro_rt); 1701 } 1702 1703 return (maxmtu); 1704} 1705#endif /* INET6 */ 1706 1707#ifdef IPSEC 1708/* compute ESP/AH header size for TCP, including outer IP header. */ 1709size_t 1710ipsec_hdrsiz_tcp(struct tcpcb *tp) 1711{ 1712 struct inpcb *inp; 1713 struct mbuf *m; 1714 size_t hdrsiz; 1715 struct ip *ip; 1716#ifdef INET6 1717 struct ip6_hdr *ip6; 1718#endif 1719 struct tcphdr *th; 1720 1721 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1722 return (0); 1723 MGETHDR(m, M_DONTWAIT, MT_DATA); 1724 if (!m) 1725 return (0); 1726 1727#ifdef INET6 1728 if ((inp->inp_vflag & INP_IPV6) != 0) { 1729 ip6 = mtod(m, struct ip6_hdr *); 1730 th = (struct tcphdr *)(ip6 + 1); 1731 m->m_pkthdr.len = m->m_len = 1732 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1733 tcpip_fillheaders(inp, ip6, th); 1734 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1735 } else 1736#endif /* INET6 */ 1737 { 1738 ip = mtod(m, struct ip *); 1739 th = (struct tcphdr *)(ip + 1); 1740 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1741 tcpip_fillheaders(inp, ip, th); 1742 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1743 } 1744 1745 m_free(m); 1746 return (hdrsiz); 1747} 1748#endif /*IPSEC*/ 1749 1750/* 1751 * Move a TCP connection into TIME_WAIT state. 1752 * tcbinfo is locked. 1753 * inp is locked, and is unlocked before returning. 1754 */ 1755void 1756tcp_twstart(struct tcpcb *tp) 1757{ 1758 struct tcptw *tw; 1759 struct inpcb *inp = tp->t_inpcb; 1760 int acknow; 1761 struct socket *so; 1762 1763 INP_INFO_WLOCK_ASSERT(&tcbinfo); /* tcp_timer_2msl_reset(). */ 1764 INP_LOCK_ASSERT(inp); 1765 1766 if (nolocaltimewait && in_localip(inp->inp_faddr)) { 1767 tp = tcp_close(tp); 1768 if (tp != NULL) 1769 INP_UNLOCK(inp); 1770 return; 1771 } 1772 1773 tw = uma_zalloc(tcptw_zone, M_NOWAIT); 1774 if (tw == NULL) { 1775 tw = tcp_timer_2msl_tw(1); 1776 if (tw == NULL) { 1777 tp = tcp_close(tp); 1778 if (tp != NULL) 1779 INP_UNLOCK(inp); 1780 return; 1781 } 1782 } 1783 tw->tw_inpcb = inp; 1784 1785 /* 1786 * Recover last window size sent. 1787 */ 1788 tw->last_win = (tp->rcv_adv - tp->rcv_nxt) >> tp->rcv_scale; 1789 1790 /* 1791 * Set t_recent if timestamps are used on the connection. 1792 */ 1793 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 1794 (TF_REQ_TSTMP|TF_RCVD_TSTMP)) 1795 tw->t_recent = tp->ts_recent; 1796 else 1797 tw->t_recent = 0; 1798 1799 tw->snd_nxt = tp->snd_nxt; 1800 tw->rcv_nxt = tp->rcv_nxt; 1801 tw->iss = tp->iss; 1802 tw->irs = tp->irs; 1803 tw->t_starttime = tp->t_starttime; 1804 tw->tw_time = 0; 1805 1806/* XXX 1807 * If this code will 1808 * be used for fin-wait-2 state also, then we may need 1809 * a ts_recent from the last segment. 1810 */ 1811 acknow = tp->t_flags & TF_ACKNOW; 1812 1813 /* 1814 * First, discard tcpcb state, which includes stopping its timers and 1815 * freeing it. tcp_discardcb() used to also release the inpcb, but 1816 * that work is now done in the caller. 1817 * 1818 * Note: soisdisconnected() call used to be made in tcp_discardcb(), 1819 * and might not be needed here any longer. 1820 */ 1821 tcp_discardcb(tp); 1822 so = inp->inp_socket; 1823 soisdisconnected(so); 1824 SOCK_LOCK(so); 1825 tw->tw_cred = crhold(so->so_cred); 1826 tw->tw_so_options = so->so_options; 1827 SOCK_UNLOCK(so); 1828 if (acknow) 1829 tcp_twrespond(tw, TH_ACK); 1830 inp->inp_ppcb = tw; 1831 inp->inp_vflag |= INP_TIMEWAIT; 1832 tcp_timer_2msl_reset(tw, 0); 1833 1834 /* 1835 * If the inpcb owns the sole reference to the socket, then we can 1836 * detach and free the socket as it is not needed in time wait. 1837 */ 1838 if (inp->inp_vflag & INP_SOCKREF) { 1839 KASSERT(so->so_state & SS_PROTOREF, 1840 ("tcp_twstart: !SS_PROTOREF")); 1841 inp->inp_vflag &= ~INP_SOCKREF; 1842 INP_UNLOCK(inp); 1843 ACCEPT_LOCK(); 1844 SOCK_LOCK(so); 1845 so->so_state &= ~SS_PROTOREF; 1846 sofree(so); 1847 } else 1848 INP_UNLOCK(inp); 1849} 1850 1851#if 0 1852/* 1853 * The appromixate rate of ISN increase of Microsoft TCP stacks; 1854 * the actual rate is slightly higher due to the addition of 1855 * random positive increments. 1856 * 1857 * Most other new OSes use semi-randomized ISN values, so we 1858 * do not need to worry about them. 1859 */ 1860#define MS_ISN_BYTES_PER_SECOND 250000 1861 1862/* 1863 * Determine if the ISN we will generate has advanced beyond the last 1864 * sequence number used by the previous connection. If so, indicate 1865 * that it is safe to recycle this tw socket by returning 1. 1866 */ 1867int 1868tcp_twrecycleable(struct tcptw *tw) 1869{ 1870 tcp_seq new_iss = tw->iss; 1871 tcp_seq new_irs = tw->irs; 1872 1873 INP_INFO_WLOCK_ASSERT(&tcbinfo); 1874 new_iss += (ticks - tw->t_starttime) * (ISN_BYTES_PER_SECOND / hz); 1875 new_irs += (ticks - tw->t_starttime) * (MS_ISN_BYTES_PER_SECOND / hz); 1876 1877 if (SEQ_GT(new_iss, tw->snd_nxt) && SEQ_GT(new_irs, tw->rcv_nxt)) 1878 return (1); 1879 else 1880 return (0); 1881} 1882#endif 1883 1884void 1885tcp_twclose(struct tcptw *tw, int reuse) 1886{ 1887 struct socket *so; 1888 struct inpcb *inp; 1889 1890 /* 1891 * At this point, we are in one of two situations: 1892 * 1893 * (1) We have no socket, just an inpcb<->twtcp pair. We can free 1894 * all state. 1895 * 1896 * (2) We have a socket -- if we own a reference, release it and 1897 * notify the socket layer. 1898 */ 1899 inp = tw->tw_inpcb; 1900 KASSERT((inp->inp_vflag & INP_TIMEWAIT), ("tcp_twclose: !timewait")); 1901 KASSERT(intotw(inp) == tw, ("tcp_twclose: inp_ppcb != tw")); 1902 INP_INFO_WLOCK_ASSERT(&tcbinfo); /* tcp_timer_2msl_stop(). */ 1903 INP_LOCK_ASSERT(inp); 1904 1905 tw->tw_inpcb = NULL; 1906 tcp_timer_2msl_stop(tw); 1907 inp->inp_ppcb = NULL; 1908 in_pcbdrop(inp); 1909 1910 so = inp->inp_socket; 1911 if (so != NULL) { 1912 /* 1913 * If there's a socket, handle two cases: first, we own a 1914 * strong reference, which we will now release, or we don't 1915 * in which case another reference exists (XXXRW: think 1916 * about this more), and we don't need to take action. 1917 */ 1918 if (inp->inp_vflag & INP_SOCKREF) { 1919 inp->inp_vflag &= ~INP_SOCKREF; 1920 INP_UNLOCK(inp); 1921 ACCEPT_LOCK(); 1922 SOCK_LOCK(so); 1923 KASSERT(so->so_state & SS_PROTOREF, 1924 ("tcp_twclose: INP_SOCKREF && !SS_PROTOREF")); 1925 so->so_state &= ~SS_PROTOREF; 1926 sofree(so); 1927 } else { 1928 /* 1929 * If we don't own the only reference, the socket and 1930 * inpcb need to be left around to be handled by 1931 * tcp_usr_detach() later. 1932 */ 1933 INP_UNLOCK(inp); 1934 } 1935 } else { 1936#ifdef INET6 1937 if (inp->inp_vflag & INP_IPV6PROTO) 1938 in6_pcbfree(inp); 1939 else 1940#endif 1941 in_pcbfree(inp); 1942 } 1943 tcpstat.tcps_closed++; 1944 crfree(tw->tw_cred); 1945 tw->tw_cred = NULL; 1946 if (reuse) 1947 return; 1948 uma_zfree(tcptw_zone, tw); 1949} 1950 1951int 1952tcp_twrespond(struct tcptw *tw, int flags) 1953{ 1954 struct inpcb *inp = tw->tw_inpcb; 1955 struct tcphdr *th; 1956 struct mbuf *m; 1957 struct ip *ip = NULL; 1958 u_int8_t *optp; 1959 u_int hdrlen, optlen; 1960 int error; 1961#ifdef INET6 1962 struct ip6_hdr *ip6 = NULL; 1963 int isipv6 = inp->inp_inc.inc_isipv6; 1964#endif 1965 1966 INP_LOCK_ASSERT(inp); 1967 1968 m = m_gethdr(M_DONTWAIT, MT_DATA); 1969 if (m == NULL) 1970 return (ENOBUFS); 1971 m->m_data += max_linkhdr; 1972 1973#ifdef MAC 1974 mac_create_mbuf_from_inpcb(inp, m); 1975#endif 1976 1977#ifdef INET6 1978 if (isipv6) { 1979 hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1980 ip6 = mtod(m, struct ip6_hdr *); 1981 th = (struct tcphdr *)(ip6 + 1); 1982 tcpip_fillheaders(inp, ip6, th); 1983 } else 1984#endif 1985 { 1986 hdrlen = sizeof(struct tcpiphdr); 1987 ip = mtod(m, struct ip *); 1988 th = (struct tcphdr *)(ip + 1); 1989 tcpip_fillheaders(inp, ip, th); 1990 } 1991 optp = (u_int8_t *)(th + 1); 1992 1993 /* 1994 * Send a timestamp and echo-reply if both our side and our peer 1995 * have sent timestamps in our SYN's and this is not a RST. 1996 */ 1997 if (tw->t_recent && flags == TH_ACK) { 1998 u_int32_t *lp = (u_int32_t *)optp; 1999 2000 /* Form timestamp option as shown in appendix A of RFC 1323. */ 2001 *lp++ = htonl(TCPOPT_TSTAMP_HDR); 2002 *lp++ = htonl(ticks); 2003 *lp = htonl(tw->t_recent); 2004 optp += TCPOLEN_TSTAMP_APPA; 2005 } 2006 2007 optlen = optp - (u_int8_t *)(th + 1); 2008 2009 m->m_len = hdrlen + optlen; 2010 m->m_pkthdr.len = m->m_len; 2011 2012 KASSERT(max_linkhdr + m->m_len <= MHLEN, ("tcptw: mbuf too small")); 2013 2014 th->th_seq = htonl(tw->snd_nxt); 2015 th->th_ack = htonl(tw->rcv_nxt); 2016 th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; 2017 th->th_flags = flags; 2018 th->th_win = htons(tw->last_win); 2019 2020#ifdef INET6 2021 if (isipv6) { 2022 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), 2023 sizeof(struct tcphdr) + optlen); 2024 ip6->ip6_hlim = in6_selecthlim(inp, NULL); 2025 error = ip6_output(m, inp->in6p_outputopts, NULL, 2026 (tw->tw_so_options & SO_DONTROUTE), NULL, NULL, inp); 2027 } else 2028#endif 2029 { 2030 th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 2031 htons(sizeof(struct tcphdr) + optlen + IPPROTO_TCP)); 2032 m->m_pkthdr.csum_flags = CSUM_TCP; 2033 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 2034 ip->ip_len = m->m_pkthdr.len; 2035 if (path_mtu_discovery) 2036 ip->ip_off |= IP_DF; 2037 error = ip_output(m, inp->inp_options, NULL, 2038 ((tw->tw_so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0), 2039 NULL, inp); 2040 } 2041 if (flags & TH_ACK) 2042 tcpstat.tcps_sndacks++; 2043 else 2044 tcpstat.tcps_sndctrl++; 2045 tcpstat.tcps_sndtotal++; 2046 return (error); 2047} 2048 2049/* 2050 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 2051 * 2052 * This code attempts to calculate the bandwidth-delay product as a 2053 * means of determining the optimal window size to maximize bandwidth, 2054 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 2055 * routers. This code also does a fairly good job keeping RTTs in check 2056 * across slow links like modems. We implement an algorithm which is very 2057 * similar (but not meant to be) TCP/Vegas. The code operates on the 2058 * transmitter side of a TCP connection and so only effects the transmit 2059 * side of the connection. 2060 * 2061 * BACKGROUND: TCP makes no provision for the management of buffer space 2062 * at the end points or at the intermediate routers and switches. A TCP 2063 * stream, whether using NewReno or not, will eventually buffer as 2064 * many packets as it is able and the only reason this typically works is 2065 * due to the fairly small default buffers made available for a connection 2066 * (typicaly 16K or 32K). As machines use larger windows and/or window 2067 * scaling it is now fairly easy for even a single TCP connection to blow-out 2068 * all available buffer space not only on the local interface, but on 2069 * intermediate routers and switches as well. NewReno makes a misguided 2070 * attempt to 'solve' this problem by waiting for an actual failure to occur, 2071 * then backing off, then steadily increasing the window again until another 2072 * failure occurs, ad-infinitum. This results in terrible oscillation that 2073 * is only made worse as network loads increase and the idea of intentionally 2074 * blowing out network buffers is, frankly, a terrible way to manage network 2075 * resources. 2076 * 2077 * It is far better to limit the transmit window prior to the failure 2078 * condition being achieved. There are two general ways to do this: First 2079 * you can 'scan' through different transmit window sizes and locate the 2080 * point where the RTT stops increasing, indicating that you have filled the 2081 * pipe, then scan backwards until you note that RTT stops decreasing, then 2082 * repeat ad-infinitum. This method works in principle but has severe 2083 * implementation issues due to RTT variances, timer granularity, and 2084 * instability in the algorithm which can lead to many false positives and 2085 * create oscillations as well as interact badly with other TCP streams 2086 * implementing the same algorithm. 2087 * 2088 * The second method is to limit the window to the bandwidth delay product 2089 * of the link. This is the method we implement. RTT variances and our 2090 * own manipulation of the congestion window, bwnd, can potentially 2091 * destabilize the algorithm. For this reason we have to stabilize the 2092 * elements used to calculate the window. We do this by using the minimum 2093 * observed RTT, the long term average of the observed bandwidth, and 2094 * by adding two segments worth of slop. It isn't perfect but it is able 2095 * to react to changing conditions and gives us a very stable basis on 2096 * which to extend the algorithm. 2097 */ 2098void 2099tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 2100{ 2101 u_long bw; 2102 u_long bwnd; 2103 int save_ticks; 2104 2105 INP_LOCK_ASSERT(tp->t_inpcb); 2106 2107 /* 2108 * If inflight_enable is disabled in the middle of a tcp connection, 2109 * make sure snd_bwnd is effectively disabled. 2110 */ 2111 if (tcp_inflight_enable == 0 || tp->t_rttlow < tcp_inflight_rttthresh) { 2112 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 2113 tp->snd_bandwidth = 0; 2114 return; 2115 } 2116 2117 /* 2118 * Figure out the bandwidth. Due to the tick granularity this 2119 * is a very rough number and it MUST be averaged over a fairly 2120 * long period of time. XXX we need to take into account a link 2121 * that is not using all available bandwidth, but for now our 2122 * slop will ramp us up if this case occurs and the bandwidth later 2123 * increases. 2124 * 2125 * Note: if ticks rollover 'bw' may wind up negative. We must 2126 * effectively reset t_bw_rtttime for this case. 2127 */ 2128 save_ticks = ticks; 2129 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 2130 return; 2131 2132 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 2133 (save_ticks - tp->t_bw_rtttime); 2134 tp->t_bw_rtttime = save_ticks; 2135 tp->t_bw_rtseq = ack_seq; 2136 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 2137 return; 2138 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 2139 2140 tp->snd_bandwidth = bw; 2141 2142 /* 2143 * Calculate the semi-static bandwidth delay product, plus two maximal 2144 * segments. The additional slop puts us squarely in the sweet 2145 * spot and also handles the bandwidth run-up case and stabilization. 2146 * Without the slop we could be locking ourselves into a lower 2147 * bandwidth. 2148 * 2149 * Situations Handled: 2150 * (1) Prevents over-queueing of packets on LANs, especially on 2151 * high speed LANs, allowing larger TCP buffers to be 2152 * specified, and also does a good job preventing 2153 * over-queueing of packets over choke points like modems 2154 * (at least for the transmit side). 2155 * 2156 * (2) Is able to handle changing network loads (bandwidth 2157 * drops so bwnd drops, bandwidth increases so bwnd 2158 * increases). 2159 * 2160 * (3) Theoretically should stabilize in the face of multiple 2161 * connections implementing the same algorithm (this may need 2162 * a little work). 2163 * 2164 * (4) Stability value (defaults to 20 = 2 maximal packets) can 2165 * be adjusted with a sysctl but typically only needs to be 2166 * on very slow connections. A value no smaller then 5 2167 * should be used, but only reduce this default if you have 2168 * no other choice. 2169 */ 2170#define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 2171 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + tcp_inflight_stab * tp->t_maxseg / 10; 2172#undef USERTT 2173 2174 if (tcp_inflight_debug > 0) { 2175 static int ltime; 2176 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 2177 ltime = ticks; 2178 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 2179 tp, 2180 bw, 2181 tp->t_rttbest, 2182 tp->t_srtt, 2183 bwnd 2184 ); 2185 } 2186 } 2187 if ((long)bwnd < tcp_inflight_min) 2188 bwnd = tcp_inflight_min; 2189 if (bwnd > tcp_inflight_max) 2190 bwnd = tcp_inflight_max; 2191 if ((long)bwnd < tp->t_maxseg * 2) 2192 bwnd = tp->t_maxseg * 2; 2193 tp->snd_bwnd = bwnd; 2194} 2195 2196#ifdef TCP_SIGNATURE 2197/* 2198 * Callback function invoked by m_apply() to digest TCP segment data 2199 * contained within an mbuf chain. 2200 */ 2201static int 2202tcp_signature_apply(void *fstate, void *data, u_int len) 2203{ 2204 2205 MD5Update(fstate, (u_char *)data, len); 2206 return (0); 2207} 2208 2209/* 2210 * Compute TCP-MD5 hash of a TCPv4 segment. (RFC2385) 2211 * 2212 * Parameters: 2213 * m pointer to head of mbuf chain 2214 * off0 offset to TCP header within the mbuf chain 2215 * len length of TCP segment data, excluding options 2216 * optlen length of TCP segment options 2217 * buf pointer to storage for computed MD5 digest 2218 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 2219 * 2220 * We do this over ip, tcphdr, segment data, and the key in the SADB. 2221 * When called from tcp_input(), we can be sure that th_sum has been 2222 * zeroed out and verified already. 2223 * 2224 * This function is for IPv4 use only. Calling this function with an 2225 * IPv6 packet in the mbuf chain will yield undefined results. 2226 * 2227 * Return 0 if successful, otherwise return -1. 2228 * 2229 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 2230 * search with the destination IP address, and a 'magic SPI' to be 2231 * determined by the application. This is hardcoded elsewhere to 1179 2232 * right now. Another branch of this code exists which uses the SPD to 2233 * specify per-application flows but it is unstable. 2234 */ 2235int 2236tcp_signature_compute(struct mbuf *m, int off0, int len, int optlen, 2237 u_char *buf, u_int direction) 2238{ 2239 union sockaddr_union dst; 2240 struct ippseudo ippseudo; 2241 MD5_CTX ctx; 2242 int doff; 2243 struct ip *ip; 2244 struct ipovly *ipovly; 2245 struct secasvar *sav; 2246 struct tcphdr *th; 2247 u_short savecsum; 2248 2249 KASSERT(m != NULL, ("NULL mbuf chain")); 2250 KASSERT(buf != NULL, ("NULL signature pointer")); 2251 2252 /* Extract the destination from the IP header in the mbuf. */ 2253 ip = mtod(m, struct ip *); 2254 bzero(&dst, sizeof(union sockaddr_union)); 2255 dst.sa.sa_len = sizeof(struct sockaddr_in); 2256 dst.sa.sa_family = AF_INET; 2257 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 2258 ip->ip_src : ip->ip_dst; 2259 2260 /* Look up an SADB entry which matches the address of the peer. */ 2261 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2262 if (sav == NULL) { 2263 printf("%s: SADB lookup failed for %s\n", __func__, 2264 inet_ntoa(dst.sin.sin_addr)); 2265 return (EINVAL); 2266 } 2267 2268 MD5Init(&ctx); 2269 ipovly = (struct ipovly *)ip; 2270 th = (struct tcphdr *)((u_char *)ip + off0); 2271 doff = off0 + sizeof(struct tcphdr) + optlen; 2272 2273 /* 2274 * Step 1: Update MD5 hash with IP pseudo-header. 2275 * 2276 * XXX The ippseudo header MUST be digested in network byte order, 2277 * or else we'll fail the regression test. Assume all fields we've 2278 * been doing arithmetic on have been in host byte order. 2279 * XXX One cannot depend on ipovly->ih_len here. When called from 2280 * tcp_output(), the underlying ip_len member has not yet been set. 2281 */ 2282 ippseudo.ippseudo_src = ipovly->ih_src; 2283 ippseudo.ippseudo_dst = ipovly->ih_dst; 2284 ippseudo.ippseudo_pad = 0; 2285 ippseudo.ippseudo_p = IPPROTO_TCP; 2286 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + optlen); 2287 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2288 2289 /* 2290 * Step 2: Update MD5 hash with TCP header, excluding options. 2291 * The TCP checksum must be set to zero. 2292 */ 2293 savecsum = th->th_sum; 2294 th->th_sum = 0; 2295 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2296 th->th_sum = savecsum; 2297 2298 /* 2299 * Step 3: Update MD5 hash with TCP segment data. 2300 * Use m_apply() to avoid an early m_pullup(). 2301 */ 2302 if (len > 0) 2303 m_apply(m, doff, len, tcp_signature_apply, &ctx); 2304 2305 /* 2306 * Step 4: Update MD5 hash with shared secret. 2307 */ 2308 MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); 2309 MD5Final(buf, &ctx); 2310 2311 key_sa_recordxfer(sav, m); 2312 KEY_FREESAV(&sav); 2313 return (0); 2314} 2315#endif /* TCP_SIGNATURE */ 2316 2317static int 2318sysctl_drop(SYSCTL_HANDLER_ARGS) 2319{ 2320 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 2321 struct sockaddr_storage addrs[2]; 2322 struct inpcb *inp; 2323 struct tcpcb *tp; 2324 struct tcptw *tw; 2325 struct sockaddr_in *fin, *lin; 2326#ifdef INET6 2327 struct sockaddr_in6 *fin6, *lin6; 2328 struct in6_addr f6, l6; 2329#endif 2330 int error; 2331 2332 inp = NULL; 2333 fin = lin = NULL; 2334#ifdef INET6 2335 fin6 = lin6 = NULL; 2336#endif 2337 error = 0; 2338 2339 if (req->oldptr != NULL || req->oldlen != 0) 2340 return (EINVAL); 2341 if (req->newptr == NULL) 2342 return (EPERM); 2343 if (req->newlen < sizeof(addrs)) 2344 return (ENOMEM); 2345 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2346 if (error) 2347 return (error); 2348 2349 switch (addrs[0].ss_family) { 2350#ifdef INET6 2351 case AF_INET6: 2352 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2353 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2354 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2355 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2356 return (EINVAL); 2357 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2358 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2359 return (EINVAL); 2360 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2361 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2362 fin = (struct sockaddr_in *)&addrs[0]; 2363 lin = (struct sockaddr_in *)&addrs[1]; 2364 break; 2365 } 2366 error = sa6_embedscope(fin6, ip6_use_defzone); 2367 if (error) 2368 return (error); 2369 error = sa6_embedscope(lin6, ip6_use_defzone); 2370 if (error) 2371 return (error); 2372 break; 2373#endif 2374 case AF_INET: 2375 fin = (struct sockaddr_in *)&addrs[0]; 2376 lin = (struct sockaddr_in *)&addrs[1]; 2377 if (fin->sin_len != sizeof(struct sockaddr_in) || 2378 lin->sin_len != sizeof(struct sockaddr_in)) 2379 return (EINVAL); 2380 break; 2381 default: 2382 return (EINVAL); 2383 } 2384 INP_INFO_WLOCK(&tcbinfo); 2385 switch (addrs[0].ss_family) { 2386#ifdef INET6 2387 case AF_INET6: 2388 inp = in6_pcblookup_hash(&tcbinfo, &f6, fin6->sin6_port, 2389 &l6, lin6->sin6_port, 0, NULL); 2390 break; 2391#endif 2392 case AF_INET: 2393 inp = in_pcblookup_hash(&tcbinfo, fin->sin_addr, fin->sin_port, 2394 lin->sin_addr, lin->sin_port, 0, NULL); 2395 break; 2396 } 2397 if (inp != NULL) { 2398 INP_LOCK(inp); 2399 if (inp->inp_vflag & INP_TIMEWAIT) { 2400 /* 2401 * XXXRW: There currently exists a state where an 2402 * inpcb is present, but its timewait state has been 2403 * discarded. For now, don't allow dropping of this 2404 * type of inpcb. 2405 */ 2406 tw = intotw(inp); 2407 if (tw != NULL) 2408 tcp_twclose(tw, 0); 2409 } else if (!(inp->inp_vflag & INP_DROPPED) && 2410 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2411 tp = intotcpcb(inp); 2412 tcp_drop(tp, ECONNABORTED); 2413 } 2414 INP_UNLOCK(inp); 2415 } else 2416 error = ESRCH; 2417 INP_INFO_WUNLOCK(&tcbinfo); 2418 return (error); 2419} 2420 2421SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2422 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2423 0, sysctl_drop, "", "Drop TCP connection"); 2424