VirtualBox

source: vbox/trunk/src/VBox/Devices/Network/slirp/tcp_timer.h@ 28587

Last change on this file since 28587 was 28449, checked in by vboxsync, 15 years ago

NAT: slirp file headers

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
File size: 6.8 KB
Line 
1/* $Id: tcp_timer.h 28449 2010-04-19 09:52:59Z vboxsync $ */
2/** @file
3 * NAT - TCP timer (declarations/defines).
4 */
5
6/*
7 * Copyright (C) 2006-2010 Sun Microsystems, Inc.
8 *
9 * This file is part of VirtualBox Open Source Edition (OSE), as
10 * available from http://www.virtualbox.org. This file is free software;
11 * you can redistribute it and/or modify it under the terms of the GNU
12 * General Public License (GPL) as published by the Free Software
13 * Foundation, in version 2 as it comes in the "COPYING" file of the
14 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16 *
17 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
18 * Clara, CA 95054 USA or visit http://www.sun.com if you need
19 * additional information or have any questions.
20 */
21
22/*
23 * This code is based on:
24 *
25 * Copyright (c) 1982, 1986, 1993
26 * The Regents of the University of California. All rights reserved.
27 *
28 * Redistribution and use in source and binary forms, with or without
29 * modification, are permitted provided that the following conditions
30 * are met:
31 * 1. Redistributions of source code must retain the above copyright
32 * notice, this list of conditions and the following disclaimer.
33 * 2. Redistributions in binary form must reproduce the above copyright
34 * notice, this list of conditions and the following disclaimer in the
35 * documentation and/or other materials provided with the distribution.
36 * 3. All advertising materials mentioning features or use of this software
37 * must display the following acknowledgement:
38 * This product includes software developed by the University of
39 * California, Berkeley and its contributors.
40 * 4. Neither the name of the University nor the names of its contributors
41 * may be used to endorse or promote products derived from this software
42 * without specific prior written permission.
43 *
44 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
45 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
46 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
47 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
48 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
49 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
50 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
51 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
52 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
53 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
54 * SUCH DAMAGE.
55 *
56 * @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93
57 * tcp_timer.h,v 1.4 1994/08/21 05:27:38 paul Exp
58 */
59
60#ifndef _TCP_TIMER_H_
61#define _TCP_TIMER_H_
62
63/*
64 * Definitions of the TCP timers. These timers are counted
65 * down PR_SLOWHZ times a second.
66 */
67#define TCPT_NTIMERS 4
68
69#define TCPT_REXMT 0 /* retransmit */
70#define TCPT_PERSIST 1 /* retransmit persistence */
71#define TCPT_KEEP 2 /* keep alive */
72#define TCPT_2MSL 3 /* 2*msl quiet time timer */
73
74/*
75 * The TCPT_REXMT timer is used to force retransmissions.
76 * The TCP has the TCPT_REXMT timer set whenever segments
77 * have been sent for which ACKs are expected but not yet
78 * received. If an ACK is received which advances tp->snd_una,
79 * then the retransmit timer is cleared (if there are no more
80 * outstanding segments) or reset to the base value (if there
81 * are more ACKs expected). Whenever the retransmit timer goes off,
82 * we retransmit one unacknowledged segment, and do a backoff
83 * on the retransmit timer.
84 *
85 * The TCPT_PERSIST timer is used to keep window size information
86 * flowing even if the window goes shut. If all previous transmissions
87 * have been acknowledged (so that there are no retransmissions in progress),
88 * and the window is too small to bother sending anything, then we start
89 * the TCPT_PERSIST timer. When it expires, if the window is nonzero,
90 * we go to transmit state. Otherwise, at intervals send a single byte
91 * into the peer's window to force him to update our window information.
92 * We do this at most as often as TCPT_PERSMIN time intervals,
93 * but no more frequently than the current estimate of round-trip
94 * packet time. The TCPT_PERSIST timer is cleared whenever we receive
95 * a window update from the peer.
96 *
97 * The TCPT_KEEP timer is used to keep connections alive. If an
98 * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time,
99 * but not yet established, then we drop the connection. Once the connection
100 * is established, if the connection is idle for TCPTV_KEEP_IDLE time
101 * (and keepalives have been enabled on the socket), we begin to probe
102 * the connection. We force the peer to send us a segment by sending:
103 * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
104 * This segment is (deliberately) outside the window, and should elicit
105 * an ack segment in response from the peer. If, despite the TCPT_KEEP
106 * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE
107 * amount of time probing, then we drop the connection.
108 */
109
110/*
111 * Time constants.
112 */
113#define TCPTV_MSL ( 5*PR_SLOWHZ) /* max seg lifetime (hah!) */
114
115#define TCPTV_SRTTBASE 0 /* base roundtrip time;
116 if 0, no idea yet */
117#define TCPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */
118
119#define TCPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistence */
120#define TCPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */
121
122#define TCPTV_KEEP_INIT ( 75*PR_SLOWHZ) /* initial connect keep alive */
123#define TCPTV_KEEP_IDLE (120*60*PR_SLOWHZ) /* dflt time before probing */
124#define TCPTV_KEEPINTVL ( 75*PR_SLOWHZ) /* default probe interval */
125#define TCPTV_KEEPCNT 8 /* max probes before drop */
126
127#define TCPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */
128#define TCPTV_REXMTMAX ( 12*PR_SLOWHZ) /* max allowable REXMT value */
129
130#define TCP_LINGERTIME 120 /* linger at most 2 minutes */
131
132#define TCP_MAXRXTSHIFT 12 /* maximum retransmits */
133
134
135#ifdef TCPTIMERS
136char *tcptimers[] =
137 { "REXMT", "PERSIST", "KEEP", "2MSL" };
138#endif
139
140/*
141 * Force a time value to be in a certain range.
142 */
143#define TCPT_RANGESET(tv, value, tvmin, tvmax) { \
144 (tv) = (value); \
145 if ((tv) < (tvmin)) \
146 (tv) = (tvmin); \
147 else if ((tv) > (tvmax)) \
148 (tv) = (tvmax); \
149}
150
151extern const int tcp_backoff[];
152
153struct tcpcb;
154
155void tcp_fasttimo (PNATState);
156void tcp_slowtimo (PNATState);
157void tcp_canceltimers (struct tcpcb *);
158struct tcpcb * tcp_timers (PNATState, register struct tcpcb *, int);
159
160#endif
Note: See TracBrowser for help on using the repository browser.

© 2025 Oracle Support Privacy / Do Not Sell My Info Terms of Use Trademark Policy Automated Access Etiquette