/* IBM_PROLOG_BEGIN_TAG */ /* This is an automatically generated prolog. */ /* */ /* bos720 src/bos/kernext/inet/tcp_timer.h 1.11.1.7 */ /* */ /* Licensed Materials - Property of IBM */ /* */ /* COPYRIGHT International Business Machines Corp. 1988,1993 */ /* All Rights Reserved */ /* */ /* US Government Users Restricted Rights - Use, duplication or */ /* disclosure restricted by GSA ADP Schedule Contract with IBM Corp. */ /* */ /* IBM_PROLOG_END_TAG */ /* @(#)38 1.11.1.7 src/bos/kernext/inet/tcp_timer.h, sysxinet_tcp, bos720 2/24/06 18:22:17 */ /* * COMPONENT_NAME: SYSXINET * * FUNCTIONS: TCPT_RANGESET * * * ORIGINS: 26,27,85 * * * (C) COPYRIGHT International Business Machines Corp. 1988,1993 * All Rights Reserved * Licensed Materials - Property of IBM * US Government Users Restricted Rights - Use, duplication or * disclosure restricted by GSA ADP Schedule Contract with IBM Corp. */ /* * * (c) Copyright 1991, OPEN SOFTWARE FOUNDATION, INC. * ALL RIGHTS RESERVED * */ /* * OSF/1 1.1 Snapshot 2 */ /* * Copyright (c) 1982, 1986 Regents of the University of California. * All rights reserved. * * Redistribution and use in source and binary forms are permitted provided * that: (1) source distributions retain this entire copyright notice and * comment, and (2) distributions including binaries display the following * acknowledgement: ``This product includes software developed by the * University of California, Berkeley and its contributors'' in the * documentation or other materials provided with the distribution and in * all advertising materials mentioning features or use of this software. * Neither the name of the University nor the names of its contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. * * Base: tcp_timer.h 7.6 (Berkeley) 6/29/88 * Merged: tcp_timer.h 7.8 (Berkeley) 6/28/90 */ #ifndef _TCP_TIMER_H_ #define _TCP_TIMER_H_ /* * Definitions of the TCP timers. These timers are counted * down PR_SLOWHZ times a second. */ #define TCPT_NTIMERS 4 #define TCPT_REXMT 0 /* retransmit */ #define TCPT_PERSIST 1 /* retransmit persistance */ #define TCPT_KEEP 2 /* keep alive */ #define TCPT_2MSL 3 /* 2*msl quiet time timer */ /* * The TCPT_REXMT timer is used to force retransmissions. * The TCP has the TCPT_REXMT timer set whenever segments * have been sent for which ACKs are expected but not yet * received. If an ACK is received which advances tp->snd_una, * then the retransmit timer is cleared (if there are no more * outstanding segments) or reset to the base value (if there * are more ACKs expected). Whenever the retransmit timer goes off, * we retransmit one unacknowledged segment, and do a backoff * on the retransmit timer. * * The TCPT_PERSIST timer is used to keep window size information * flowing even if the window goes shut. If all previous transmissions * have been acknowledged (so that there are no retransmissions in progress), * and the window is too small to bother sending anything, then we start * the TCPT_PERSIST timer. When it expires, if the window is nonzero, * we go to transmit state. Otherwise, at intervals send a single byte * into the peer's window to force him to update our window information. * We do this at most as often as TCPT_PERSMIN time intervals, * but no more frequently than the current estimate of round-trip * packet time. The TCPT_PERSIST timer is cleared whenever we receive * a window update from the peer. * * The TCPT_KEEP timer is used to keep connections alive. If an * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time, * but not yet established, then we drop the connection. Once the connection * is established, if the connection is idle for TCPTV_KEEP_IDLE time * (and keepalives have been enabled on the socket), we begin to probe * the connection. We force the peer to send us a segment by sending: * * This segment is (deliberately) outside the window, and should elicit * an ack segment in response from the peer. If, despite the TCPT_KEEP * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE * amount of time probing, then we drop the connection. */ #define TCP_TTL 60 /* default time to live for TCP segs */ /* * Time constants. */ #define TCPTV_MSL ( 30*PR_SLOWHZ) /* max seg lifetime (hah!) */ #define TCPTV_SRTTBASE 0 /* base roundtrip time; if 0, no idea yet */ #define TCPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */ #define TCPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistance */ #define TCPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */ #define TCPTV_KEEP_INIT ( 75*PR_SLOWHZ) /* initial connect keep alive */ #define TCPTV_KEEP_IDLE (120*60*PR_SLOWHZ) /* dflt time before probing */ #define TCPTV_KEEPINTVL ( 75*PR_SLOWHZ) /* default probe interval */ #define TCPTV_KEEPCNT 8 /* max probes before drop */ #define TCPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */ #define TCPTV_REXMTMAX ( 64*PR_SLOWHZ) /* max allowable REXMT value */ /* RTT, RTO macros with tcp_low_rto feature enabled */ #define TCPTV_LOWRTO_SRTTBASE 0 /* base roundtrip time; if 0, no idea yet */ #define TCPTV_LOWRTO_MIN 1 /* min rto = 1 timer wheel tick */ #define TCPTV_LOWRTO_REXMTMAX 64*timer_wheel_hz /* max rto = 64sec*(timer wheel ticks/sec) */ #define TCP_LOW_RTO_LENGTH 15 /* max retransmissions with low rto feature enabled */ #define TCP_LINGERTIME 120 /* linger at most 2 minutes */ #define TCPTV_TIME_WAIT 15 /* 15 second time_wait timer */ #define TCPTV_AOOT 1 /* Aix slOOw Timeout, */ #ifndef CONST #define CONST #endif #ifdef TCPTIMERS CONST char *tcptimers[] = { "REXMT", "PERSIST", "KEEP", "2MSL" }; #endif /* * Force a time value to be in a certain range. */ #define TCPT_RANGESET(tv, value, tvmin, tvmax) { \ (tv) = (value); \ if ((u_short)(tv) < (u_short)(tvmin)) \ (tv) = (tvmin); \ else if ((u_short)(tv) > (u_short)(tvmax)) \ (tv) = (tvmax); \ } #ifdef _KERNEL extern long tcp_keepidle; /* time before keepalive probes begin */ extern long tcp_keepintvl; /* time between keepalive probes */ extern long tcp_keepcnt; /* number of keepalive probes */ extern long tcp_maxidle; /* time to drop after starting probes */ extern long tcp_ttl; /* time to live for TCP segs */ extern long tcp_rtolow; /* TCP RTO backoff low watermark */ extern long tcp_rtohigh; /* TCP RTO backoff high watermark */ extern long tcp_rtolimit; /* TCP RTO backoff exponential mark */ extern long tcp_rtolength; /* TCP RTO backoff total# elements */ extern long tcp_rtoshift; /* TCP RTO backoff delta shift; the */ /* number of bit shitfs from */ /* tcp_rtolow to tcp_rtohigh inclusive */ #define TCP_BACKOFF(x) \ ( (((x)+1) >= (tcp_rtolimit)) ? (tcp_rtohigh) : \ (tcp_rtolow) << (((tcp_rtoshift)*(x))/(tcp_rtolimit)) ) #endif #endif /* _TCP_TIMER_H_ */