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source: vbox/trunk/src/VBox/Devices/Network/slirp/tcp_timer.h@ 28023

最後變更 在這個檔案從28023是 20306,由 vboxsync 提交於 16 年 前

NAT: compile fixes

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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 /* 2*msl 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 ( 5*PR_SLOWHZ) /* max seg lifetime (hah!) */
91
92#define TCPTV_SRTTBASE 0 /* base roundtrip time;
93 if 0, no idea yet */
94#define TCPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */
95
96#define TCPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistence */
97#define TCPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */
98
99#define TCPTV_KEEP_INIT ( 75*PR_SLOWHZ) /* initial connect keep alive */
100#define TCPTV_KEEP_IDLE (120*60*PR_SLOWHZ) /* dflt time before probing */
101#define TCPTV_KEEPINTVL ( 75*PR_SLOWHZ) /* default probe interval */
102#define TCPTV_KEEPCNT 8 /* max probes before drop */
103
104#define TCPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */
105#define TCPTV_REXMTMAX ( 12*PR_SLOWHZ) /* max allowable REXMT value */
106
107#define TCP_LINGERTIME 120 /* linger at most 2 minutes */
108
109#define TCP_MAXRXTSHIFT 12 /* maximum retransmits */
110
111
112#ifdef TCPTIMERS
113char *tcptimers[] =
114 { "REXMT", "PERSIST", "KEEP", "2MSL" };
115#endif
116
117/*
118 * Force a time value to be in a certain range.
119 */
120#define TCPT_RANGESET(tv, value, tvmin, tvmax) { \
121 (tv) = (value); \
122 if ((tv) < (tvmin)) \
123 (tv) = (tvmin); \
124 else if ((tv) > (tvmax)) \
125 (tv) = (tvmax); \
126}
127
128extern const int tcp_backoff[];
129
130struct tcpcb;
131
132void tcp_fasttimo (PNATState);
133void tcp_slowtimo (PNATState);
134void tcp_canceltimers (struct tcpcb *);
135struct tcpcb * tcp_timers (PNATState, register struct tcpcb *, int);
136
137#endif
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