freebsd-src/sys/netns/spp_timer.h
Peter Wemm 664a31e496 Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot).  This is consistant with the other
BSD's who made this change quite some time ago.  More commits to come.
1999-12-29 04:46:21 +00:00

129 lines
5.2 KiB
C

/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)spp_timer.h 8.1 (Berkeley) 6/10/93
* $FreeBSD$
*/
#ifndef _NETNS_SPP_TIMER_H_
#define _NETNS_SPP_TIMER_H_
/*
* Definitions of the SPP timers. These timers are counted
* down PR_SLOWHZ times a second.
*/
#define SPPT_NTIMERS 4
#define SPPT_REXMT 0 /* retransmit */
#define SPPT_PERSIST 1 /* retransmit persistance */
#define SPPT_KEEP 2 /* keep alive */
#define SPPT_2MSL 3 /* 2*msl quiet time timer */
/*
* The SPPT_REXMT timer is used to force retransmissions.
* The SPP has the SPPT_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 SPPT_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 SPPT_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 SPPT_PERSMIN time intervals,
* but no more frequently than the current estimate of round-trip
* packet time. The SPPT_PERSIST timer is cleared whenever we receive
* a window update from the peer.
*
* The SPPT_KEEP timer is used to keep connections alive. If an
* connection is idle (no segments received) for SPPTV_KEEP amount of time,
* but not yet established, then we drop the connection. If the connection
* is established, then we force the peer to send us a segment by sending:
* <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
* This segment is (deliberately) outside the window, and should elicit
* an ack segment in response from the peer. If, despite the SPPT_KEEP
* initiated segments we cannot elicit a response from a peer in SPPT_MAXIDLE
* amount of time, then we drop the connection.
*/
#define SPP_TTL 30 /* default time to live for SPP segs */
/*
* Time constants.
*/
#define SPPTV_MSL ( 15*PR_SLOWHZ) /* max seg lifetime */
#define SPPTV_SRTTBASE 0 /* base roundtrip time;
if 0, no idea yet */
#define SPPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */
#define SPPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistance */
#define SPPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */
#define SPPTV_KEEP ( 75*PR_SLOWHZ) /* keep alive - 75 secs */
#define SPPTV_MAXIDLE ( 8*SPPTV_KEEP) /* maximum allowable idle
time before drop conn */
#define SPPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */
#define SPPTV_REXMTMAX ( 64*PR_SLOWHZ) /* max allowable REXMT value */
#define SPP_LINGERTIME 120 /* linger at most 2 minutes */
#define SPP_MAXRXTSHIFT 12 /* maximum retransmits */
#ifdef SPPTIMERS
char *spptimers[] =
{ "REXMT", "PERSIST", "KEEP", "2MSL" };
#endif
/*
* Force a time value to be in a certain range.
*/
#define SPPT_RANGESET(tv, value, tvmin, tvmax) { \
(tv) = (value); \
if ((tv) < (tvmin)) \
(tv) = (tvmin); \
else if ((tv) > (tvmax)) \
(tv) = (tvmax); \
}
#ifdef _KERNEL
extern int spp_backoff[];
#endif
#endif