bostic@OKEEFFE.BERKELEY.EDU (Keith Bostic) (04/06/88)
Subject: spp_timer.h for updated IP/TCP and XNS sources for 4.3BSD
Index: sys/netns/spp_timer.h 4.3BSD
Description:
We forgot to post a copy of spp_timer.h with the updated IP/TCP
and XNS sources for 4.3BSD. A shar containing a copy is attached.
# This is a shell archive. Save it in a file, remove anything before
# this line, and then unpack it by entering "sh file". Note, it may
# create directories; files and directories will be owned by you and
# have default permissions.
#
# This archive contains:
#
# netns
# netns/spp_timer.h
#
echo c - netns
mkdir netns > /dev/null 2>&1
echo x - netns/spp_timer.h
sed 's/^X//' >netns/spp_timer.h << 'END-of-netns/spp_timer.h'
X/*
X * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
X * All rights reserved.
X *
X * Redistribution and use in source and binary forms are permitted
X * provided that this notice is preserved and that due credit is given
X * to the University of California at Berkeley. The name of the University
X * may not be used to endorse or promote products derived from this
X * software without specific prior written permission. This software
X * is provided ``as is'' without express or implied warranty.
X *
X * @(#)spp_timer.h 7.1 (Berkeley) 3/12/88
X */
X
X/*
X * Definitions of the SPP timers. These timers are counted
X * down PR_SLOWHZ times a second.
X */
X#define SPPT_NTIMERS 4
X
X#define SPPT_REXMT 0 /* retransmit */
X#define SPPT_PERSIST 1 /* retransmit persistance */
X#define SPPT_KEEP 2 /* keep alive */
X#define SPPT_2MSL 3 /* 2*msl quiet time timer */
X
X/*
X * The SPPT_REXMT timer is used to force retransmissions.
X * The SPP has the SPPT_REXMT timer set whenever segments
X * have been sent for which ACKs are expected but not yet
X * received. If an ACK is received which advances tp->snd_una,
X * then the retransmit timer is cleared (if there are no more
X * outstanding segments) or reset to the base value (if there
X * are more ACKs expected). Whenever the retransmit timer goes off,
X * we retransmit one unacknowledged segment, and do a backoff
X * on the retransmit timer.
X *
X * The SPPT_PERSIST timer is used to keep window size information
X * flowing even if the window goes shut. If all previous transmissions
X * have been acknowledged (so that there are no retransmissions in progress),
X * and the window is too small to bother sending anything, then we start
X * the SPPT_PERSIST timer. When it expires, if the window is nonzero,
X * we go to transmit state. Otherwise, at intervals send a single byte
X * into the peer's window to force him to update our window information.
X * We do this at most as often as SPPT_PERSMIN time intervals,
X * but no more frequently than the current estimate of round-trip
X * packet time. The SPPT_PERSIST timer is cleared whenever we receive
X * a window update from the peer.
X *
X * The SPPT_KEEP timer is used to keep connections alive. If an
X * connection is idle (no segments received) for SPPTV_KEEP amount of time,
X * but not yet established, then we drop the connection. If the connection
X * is established, then we force the peer to send us a segment by sending:
X * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
X * This segment is (deliberately) outside the window, and should elicit
X * an ack segment in response from the peer. If, despite the SPPT_KEEP
X * initiated segments we cannot elicit a response from a peer in SPPT_MAXIDLE
X * amount of time, then we drop the connection.
X */
X
X#define SPP_TTL 30 /* default time to live for SPP segs */
X/*
X * Time constants.
X */
X#define SPPTV_MSL ( 15*PR_SLOWHZ) /* max seg lifetime */
X#define SPPTV_SRTTBASE 0 /* base roundtrip time;
X if 0, no idea yet */
X#define SPPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */
X
X#define SPPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistance */
X#define SPPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */
X
X#define SPPTV_KEEP ( 75*PR_SLOWHZ) /* keep alive - 75 secs */
X#define SPPTV_MAXIDLE ( 8*SPPTV_KEEP) /* maximum allowable idle
X time before drop conn */
X
X#define SPPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */
X#define SPPTV_REXMTMAX ( 64*PR_SLOWHZ) /* max allowable REXMT value */
X
X#define SPP_LINGERTIME 120 /* linger at most 2 minutes */
X
X#define SPP_MAXRXTSHIFT 12 /* maximum retransmits */
X
X#ifdef SPPTIMERS
Xchar *spptimers[] =
X { "REXMT", "PERSIST", "KEEP", "2MSL" };
X#endif
X
X/*
X * Force a time value to be in a certain range.
X */
X#define SPPT_RANGESET(tv, value, tvmin, tvmax) { \
X (tv) = (value); \
X if ((tv) < (tvmin)) \
X (tv) = (tvmin); \
X else if ((tv) > (tvmax)) \
X (tv) = (tvmax); \
X}
X
X#ifdef KERNEL
Xextern int spp_backoff[];
X#endif
END-of-netns/spp_timer.h
exit