src/slirp/tcp_timer.h

/*
 * Copyright (c) 1982, 1986, 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.
 *
 *      @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93
 * tcp_timer.h,v 1.4 1994/08/21 05:27:38 paul Exp
 */

#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 persistence */
#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:
 *      <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 TCPT_KEEP
 * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE
 * amount of time probing, then we drop the connection.
 */

/*
 * Time constants.
 */
#define TCPTV_MSL       ( 5*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 persistence */
#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 */
#define TCPTV_REXMTMAX  ( 12*PR_SLOWHZ)         /* max allowable REXMT value */

#define TCP_LINGERTIME  120                     /* linger at most 2 minutes */

#define TCP_MAXRXTSHIFT 12                      /* maximum retransmits */


#ifdef  TCPTIMERS
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 ((tv) < (tvmin)) \
                (tv) = (tvmin); \
        else if ((tv) > (tvmax)) \
                (tv) = (tvmax); \
}

extern int tcp_keepidle;                /* time before keepalive probes begin */
extern int tcp_keepintvl;               /* time between keepalive probes */
extern int tcp_maxidle;                 /* time to drop after starting probes */
extern int tcp_ttl;                     /* time to live for TCP segs */
extern int tcp_backoff[];

struct tcpcb;

void tcp_fasttimo _P((void));
void tcp_slowtimo _P((void));
void tcp_canceltimers _P((struct tcpcb *));
struct tcpcb * tcp_timers _P((register struct tcpcb *, int));

#endif
Revision:	1.1
Committed:	2005-05-13T09:00:59Z (19 years, 1 month ago) by gbeauche
Content type:	text/plain
Branch:	MAIN
CVS Tags:	nigel-build-19, nigel-build-17
Log Message:	slirp user mode network emulation code from qemu
#	User	Rev	Content
1	gbeauche	1.1	/*
2			* Copyright (c) 1982, 1986, 1993
3			* The Regents of the University of California. All rights reserved.
4			*
5			* Redistribution and use in source and binary forms, with or without
6			* modification, are permitted provided that the following conditions
7			* are met:
8			* 1. Redistributions of source code must retain the above copyright
9			* notice, this list of conditions and the following disclaimer.
10			* 2. Redistributions in binary form must reproduce the above copyright
11			* notice, this list of conditions and the following disclaimer in the
12			* documentation and/or other materials provided with the distribution.
13			* 3. All advertising materials mentioning features or use of this software
14			* must display the following acknowledgement:
15			* This product includes software developed by the University of
16			* California, Berkeley and its contributors.
17			* 4. Neither the name of the University nor the names of its contributors
18			* may be used to endorse or promote products derived from this software
19			* without specific prior written permission.
20			*
21			* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24			* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31			* SUCH DAMAGE.
32			*
33			* @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93
34			* tcp_timer.h,v 1.4 1994/08/21 05:27:38 paul Exp
35			*/
36
37			#ifndef _TCP_TIMER_H_
38			#define _TCP_TIMER_H_
39
40			/*
41			* Definitions of the TCP timers. These timers are counted
42			* down PR_SLOWHZ times a second.
43			*/
44			#define TCPT_NTIMERS 4
45
46			#define TCPT_REXMT 0 /* retransmit */
47			#define TCPT_PERSIST 1 /* retransmit persistence */
48			#define TCPT_KEEP 2 /* keep alive */
49			#define TCPT_2MSL 3 /* 2msl quiet time timer /
50
51			/*
52			* The TCPT_REXMT timer is used to force retransmissions.
53			* The TCP has the TCPT_REXMT timer set whenever segments
54			* have been sent for which ACKs are expected but not yet
55			* received. If an ACK is received which advances tp->snd_una,
56			* then the retransmit timer is cleared (if there are no more
57			* outstanding segments) or reset to the base value (if there
58			* are more ACKs expected). Whenever the retransmit timer goes off,
59			* we retransmit one unacknowledged segment, and do a backoff
60			* on the retransmit timer.
61			*
62			* The TCPT_PERSIST timer is used to keep window size information
63			* flowing even if the window goes shut. If all previous transmissions
64			* have been acknowledged (so that there are no retransmissions in progress),
65			* and the window is too small to bother sending anything, then we start
66			* the TCPT_PERSIST timer. When it expires, if the window is nonzero,
67			* we go to transmit state. Otherwise, at intervals send a single byte
68			* into the peer's window to force him to update our window information.
69			* We do this at most as often as TCPT_PERSMIN time intervals,
70			* but no more frequently than the current estimate of round-trip
71			* packet time. The TCPT_PERSIST timer is cleared whenever we receive
72			* a window update from the peer.
73			*
74			* The TCPT_KEEP timer is used to keep connections alive. If an
75			* connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time,
76			* but not yet established, then we drop the connection. Once the connection
77			* is established, if the connection is idle for TCPTV_KEEP_IDLE time
78			* (and keepalives have been enabled on the socket), we begin to probe
79			* the connection. We force the peer to send us a segment by sending:
80			* <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
81			* This segment is (deliberately) outside the window, and should elicit
82			* an ack segment in response from the peer. If, despite the TCPT_KEEP
83			* initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE
84			* amount of time probing, then we drop the connection.
85			*/
86
87			/*
88			* Time constants.
89			*/
90			#define TCPTV_MSL ( 5PR_SLOWHZ) / max seg lifetime (hah!) */
91
92			#define TCPTV_SRTTBASE 0 /* base roundtrip time;
93			if 0, no idea yet */
94			#define TCPTV_SRTTDFLT ( 3PR_SLOWHZ) / assumed RTT if no info */
95
96			#define TCPTV_PERSMIN ( 5PR_SLOWHZ) / retransmit persistence */
97			#define TCPTV_PERSMAX ( 60PR_SLOWHZ) / maximum persist interval */
98
99			#define TCPTV_KEEP_INIT ( 75PR_SLOWHZ) / initial connect keep alive */
100			#define TCPTV_KEEP_IDLE (12060PR_SLOWHZ) /* dflt time before probing */
101			#define TCPTV_KEEPINTVL ( 75PR_SLOWHZ) / default probe interval */
102			#define TCPTV_KEEPCNT 8 /* max probes before drop */
103
104			#define TCPTV_MIN ( 1PR_SLOWHZ) / minimum allowable value */
105			/* #define TCPTV_REXMTMAX ( 64PR_SLOWHZ) / /* max allowable REXMT value */
106			#define TCPTV_REXMTMAX ( 12PR_SLOWHZ) / max allowable REXMT value */
107
108			#define TCP_LINGERTIME 120 /* linger at most 2 minutes */
109
110			#define TCP_MAXRXTSHIFT 12 /* maximum retransmits */
111
112
113			#ifdef TCPTIMERS
114			char *tcptimers[] =
115			{ "REXMT", "PERSIST", "KEEP", "2MSL" };
116			#endif
117
118			/*
119			* Force a time value to be in a certain range.
120			*/
121			#define TCPT_RANGESET(tv, value, tvmin, tvmax) { \
122			(tv) = (value); \
123			if ((tv) < (tvmin)) \
124			(tv) = (tvmin); \
125			else if ((tv) > (tvmax)) \
126			(tv) = (tvmax); \
127			}
128
129			extern int tcp_keepidle; /* time before keepalive probes begin */
130			extern int tcp_keepintvl; /* time between keepalive probes */
131			extern int tcp_maxidle; /* time to drop after starting probes */
132			extern int tcp_ttl; /* time to live for TCP segs */
133			extern int tcp_backoff[];
134
135			struct tcpcb;
136
137			void tcp_fasttimo _P((void));
138			void tcp_slowtimo _P((void));
139			void tcp_canceltimers _P((struct tcpcb *));
140			struct tcpcb * tcp_timers _P((register struct tcpcb *, int));
141
142			#endif