18b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project/* 28b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * Copyright (c) 1982, 1986, 1993 38b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * The Regents of the University of California. All rights reserved. 48b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * 58b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * Redistribution and use in source and binary forms, with or without 68b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * modification, are permitted provided that the following conditions 78b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * are met: 88b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * 1. Redistributions of source code must retain the above copyright 98b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * notice, this list of conditions and the following disclaimer. 108b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * 2. Redistributions in binary form must reproduce the above copyright 118b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * notice, this list of conditions and the following disclaimer in the 128b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * documentation and/or other materials provided with the distribution. 135d8f37ad78fc66901af50c762029a501561f3b23David 'Digit' Turner * 3. Neither the name of the University nor the names of its contributors 148b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * may be used to endorse or promote products derived from this software 158b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * without specific prior written permission. 168b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * 178b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 188b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 198b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 208b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 218b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 228b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 238b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 248b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 258b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 268b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 278b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * SUCH DAMAGE. 288b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * 298b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93 308b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * tcp_timer.h,v 1.4 1994/08/21 05:27:38 paul Exp 318b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project */ 328b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 338b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#ifndef _TCP_TIMER_H_ 348b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define _TCP_TIMER_H_ 358b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 368b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project/* 378b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * Definitions of the TCP timers. These timers are counted 388b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * down PR_SLOWHZ times a second. 398b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project */ 408b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPT_NTIMERS 4 418b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 428b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPT_REXMT 0 /* retransmit */ 438b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPT_PERSIST 1 /* retransmit persistence */ 448b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPT_KEEP 2 /* keep alive */ 458b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPT_2MSL 3 /* 2*msl quiet time timer */ 468b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 478b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project/* 488b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * The TCPT_REXMT timer is used to force retransmissions. 498b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * The TCP has the TCPT_REXMT timer set whenever segments 508b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * have been sent for which ACKs are expected but not yet 518b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * received. If an ACK is received which advances tp->snd_una, 528b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * then the retransmit timer is cleared (if there are no more 538b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * outstanding segments) or reset to the base value (if there 548b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * are more ACKs expected). Whenever the retransmit timer goes off, 558b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * we retransmit one unacknowledged segment, and do a backoff 568b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * on the retransmit timer. 578b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * 588b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * The TCPT_PERSIST timer is used to keep window size information 598b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * flowing even if the window goes shut. If all previous transmissions 608b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * have been acknowledged (so that there are no retransmissions in progress), 618b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * and the window is too small to bother sending anything, then we start 628b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * the TCPT_PERSIST timer. When it expires, if the window is nonzero, 638b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * we go to transmit state. Otherwise, at intervals send a single byte 648b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * into the peer's window to force him to update our window information. 658b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * We do this at most as often as TCPT_PERSMIN time intervals, 668b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * but no more frequently than the current estimate of round-trip 678b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * packet time. The TCPT_PERSIST timer is cleared whenever we receive 688b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * a window update from the peer. 698b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * 708b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * The TCPT_KEEP timer is used to keep connections alive. If an 718b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time, 728b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * but not yet established, then we drop the connection. Once the connection 738b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * is established, if the connection is idle for TCPTV_KEEP_IDLE time 748b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * (and keepalives have been enabled on the socket), we begin to probe 758b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * the connection. We force the peer to send us a segment by sending: 768b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK> 778b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * This segment is (deliberately) outside the window, and should elicit 788b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * an ack segment in response from the peer. If, despite the TCPT_KEEP 798b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE 808b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * amount of time probing, then we drop the connection. 818b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project */ 828b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 838b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project/* 848b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * Time constants. 858b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project */ 868b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_MSL ( 5*PR_SLOWHZ) /* max seg lifetime (hah!) */ 878b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 888b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_SRTTBASE 0 /* base roundtrip time; 898b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project if 0, no idea yet */ 908b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */ 918b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 928b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistence */ 938b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */ 948b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 958b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_KEEP_INIT ( 75*PR_SLOWHZ) /* initial connect keep alive */ 968b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_KEEP_IDLE (120*60*PR_SLOWHZ) /* dflt time before probing */ 978b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_KEEPINTVL ( 75*PR_SLOWHZ) /* default probe interval */ 988b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_KEEPCNT 8 /* max probes before drop */ 998b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 1008b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */ 1018b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project/* #define TCPTV_REXMTMAX ( 64*PR_SLOWHZ) */ /* max allowable REXMT value */ 1028b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPTV_REXMTMAX ( 12*PR_SLOWHZ) /* max allowable REXMT value */ 1038b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 1048b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCP_LINGERTIME 120 /* linger at most 2 minutes */ 1058b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 1068b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCP_MAXRXTSHIFT 12 /* maximum retransmits */ 1078b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 1088b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 1098b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#ifdef TCPTIMERS 1108b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Projectchar *tcptimers[] = 1118b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project { "REXMT", "PERSIST", "KEEP", "2MSL" }; 1128b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#endif 1138b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 1148b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project/* 1158b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project * Force a time value to be in a certain range. 1168b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project */ 1178b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#define TCPT_RANGESET(tv, value, tvmin, tvmax) { \ 1188b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project (tv) = (value); \ 1198b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project if ((tv) < (tvmin)) \ 1208b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project (tv) = (tvmin); \ 1218b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project else if ((tv) > (tvmax)) \ 1228b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project (tv) = (tvmax); \ 1238b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project} 1248b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 1255d8f37ad78fc66901af50c762029a501561f3b23David 'Digit' Turnerextern const int tcp_backoff[]; 1268b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 1278b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Projectstruct tcpcb; 1288b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 1298b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Projectvoid tcp_fasttimo _P((void)); 1308b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Projectvoid tcp_slowtimo _P((void)); 1318b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Projectvoid tcp_canceltimers _P((struct tcpcb *)); 1328b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project 1338b23a6c7e1aee255004dd19098d4c2462b61b849The Android Open Source Project#endif 134