V1.57 (spp_timer.h for updated IP/TCP and XNS sources for 4.3BSD)

[Keith Bostic]

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