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1 | f0cbd3ec | bellard | /*
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2 | f0cbd3ec | bellard | * Copyright (c) 1982, 1986, 1993
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3 | f0cbd3ec | bellard | * The Regents of the University of California. All rights reserved.
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4 | f0cbd3ec | bellard | *
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5 | f0cbd3ec | bellard | * Redistribution and use in source and binary forms, with or without
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6 | f0cbd3ec | bellard | * modification, are permitted provided that the following conditions
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7 | f0cbd3ec | bellard | * are met:
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8 | f0cbd3ec | bellard | * 1. Redistributions of source code must retain the above copyright
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9 | f0cbd3ec | bellard | * notice, this list of conditions and the following disclaimer.
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10 | f0cbd3ec | bellard | * 2. Redistributions in binary form must reproduce the above copyright
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11 | f0cbd3ec | bellard | * notice, this list of conditions and the following disclaimer in the
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12 | f0cbd3ec | bellard | * documentation and/or other materials provided with the distribution.
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13 | f0cbd3ec | bellard | * 3. All advertising materials mentioning features or use of this software
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14 | f0cbd3ec | bellard | * must display the following acknowledgement:
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15 | f0cbd3ec | bellard | * This product includes software developed by the University of
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16 | f0cbd3ec | bellard | * California, Berkeley and its contributors.
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17 | f0cbd3ec | bellard | * 4. Neither the name of the University nor the names of its contributors
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18 | f0cbd3ec | bellard | * may be used to endorse or promote products derived from this software
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19 | f0cbd3ec | bellard | * without specific prior written permission.
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20 | f0cbd3ec | bellard | *
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21 | f0cbd3ec | bellard | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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22 | f0cbd3ec | bellard | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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23 | f0cbd3ec | bellard | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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24 | f0cbd3ec | bellard | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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25 | f0cbd3ec | bellard | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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26 | f0cbd3ec | bellard | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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27 | f0cbd3ec | bellard | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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28 | f0cbd3ec | bellard | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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29 | f0cbd3ec | bellard | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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30 | f0cbd3ec | bellard | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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31 | f0cbd3ec | bellard | * SUCH DAMAGE.
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32 | f0cbd3ec | bellard | *
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33 | f0cbd3ec | bellard | * @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93
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34 | f0cbd3ec | bellard | * tcp_timer.h,v 1.4 1994/08/21 05:27:38 paul Exp
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35 | f0cbd3ec | bellard | */
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36 | f0cbd3ec | bellard | |
37 | f0cbd3ec | bellard | #ifndef _TCP_TIMER_H_
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38 | f0cbd3ec | bellard | #define _TCP_TIMER_H_
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39 | f0cbd3ec | bellard | |
40 | f0cbd3ec | bellard | /*
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41 | f0cbd3ec | bellard | * Definitions of the TCP timers. These timers are counted
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42 | f0cbd3ec | bellard | * down PR_SLOWHZ times a second.
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43 | f0cbd3ec | bellard | */
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44 | f0cbd3ec | bellard | #define TCPT_NTIMERS 4 |
45 | f0cbd3ec | bellard | |
46 | f0cbd3ec | bellard | #define TCPT_REXMT 0 /* retransmit */ |
47 | f0cbd3ec | bellard | #define TCPT_PERSIST 1 /* retransmit persistence */ |
48 | f0cbd3ec | bellard | #define TCPT_KEEP 2 /* keep alive */ |
49 | f0cbd3ec | bellard | #define TCPT_2MSL 3 /* 2*msl quiet time timer */ |
50 | f0cbd3ec | bellard | |
51 | f0cbd3ec | bellard | /*
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52 | f0cbd3ec | bellard | * The TCPT_REXMT timer is used to force retransmissions.
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53 | f0cbd3ec | bellard | * The TCP has the TCPT_REXMT timer set whenever segments
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54 | f0cbd3ec | bellard | * have been sent for which ACKs are expected but not yet
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55 | f0cbd3ec | bellard | * received. If an ACK is received which advances tp->snd_una,
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56 | f0cbd3ec | bellard | * then the retransmit timer is cleared (if there are no more
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57 | f0cbd3ec | bellard | * outstanding segments) or reset to the base value (if there
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58 | f0cbd3ec | bellard | * are more ACKs expected). Whenever the retransmit timer goes off,
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59 | f0cbd3ec | bellard | * we retransmit one unacknowledged segment, and do a backoff
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60 | f0cbd3ec | bellard | * on the retransmit timer.
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61 | f0cbd3ec | bellard | *
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62 | f0cbd3ec | bellard | * The TCPT_PERSIST timer is used to keep window size information
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63 | f0cbd3ec | bellard | * flowing even if the window goes shut. If all previous transmissions
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64 | f0cbd3ec | bellard | * have been acknowledged (so that there are no retransmissions in progress),
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65 | f0cbd3ec | bellard | * and the window is too small to bother sending anything, then we start
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66 | f0cbd3ec | bellard | * the TCPT_PERSIST timer. When it expires, if the window is nonzero,
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67 | f0cbd3ec | bellard | * we go to transmit state. Otherwise, at intervals send a single byte
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68 | f0cbd3ec | bellard | * into the peer's window to force him to update our window information.
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69 | f0cbd3ec | bellard | * We do this at most as often as TCPT_PERSMIN time intervals,
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70 | f0cbd3ec | bellard | * but no more frequently than the current estimate of round-trip
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71 | f0cbd3ec | bellard | * packet time. The TCPT_PERSIST timer is cleared whenever we receive
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72 | f0cbd3ec | bellard | * a window update from the peer.
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73 | f0cbd3ec | bellard | *
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74 | f0cbd3ec | bellard | * The TCPT_KEEP timer is used to keep connections alive. If an
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75 | f0cbd3ec | bellard | * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time,
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76 | f0cbd3ec | bellard | * but not yet established, then we drop the connection. Once the connection
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77 | f0cbd3ec | bellard | * is established, if the connection is idle for TCPTV_KEEP_IDLE time
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78 | f0cbd3ec | bellard | * (and keepalives have been enabled on the socket), we begin to probe
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79 | f0cbd3ec | bellard | * the connection. We force the peer to send us a segment by sending:
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80 | f0cbd3ec | bellard | * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
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81 | f0cbd3ec | bellard | * This segment is (deliberately) outside the window, and should elicit
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82 | f0cbd3ec | bellard | * an ack segment in response from the peer. If, despite the TCPT_KEEP
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83 | f0cbd3ec | bellard | * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE
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84 | f0cbd3ec | bellard | * amount of time probing, then we drop the connection.
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85 | f0cbd3ec | bellard | */
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86 | f0cbd3ec | bellard | |
87 | f0cbd3ec | bellard | /*
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88 | f0cbd3ec | bellard | * Time constants.
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89 | f0cbd3ec | bellard | */
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90 | f0cbd3ec | bellard | #define TCPTV_MSL ( 5*PR_SLOWHZ) /* max seg lifetime (hah!) */ |
91 | f0cbd3ec | bellard | |
92 | f0cbd3ec | bellard | #define TCPTV_SRTTBASE 0 /* base roundtrip time; |
93 | f0cbd3ec | bellard | if 0, no idea yet */
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94 | f0cbd3ec | bellard | #define TCPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */ |
95 | f0cbd3ec | bellard | |
96 | f0cbd3ec | bellard | #define TCPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistence */ |
97 | f0cbd3ec | bellard | #define TCPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */ |
98 | f0cbd3ec | bellard | |
99 | f0cbd3ec | bellard | #define TCPTV_KEEP_INIT ( 75*PR_SLOWHZ) /* initial connect keep alive */ |
100 | f0cbd3ec | bellard | #define TCPTV_KEEP_IDLE (120*60*PR_SLOWHZ) /* dflt time before probing */ |
101 | f0cbd3ec | bellard | #define TCPTV_KEEPINTVL ( 75*PR_SLOWHZ) /* default probe interval */ |
102 | f0cbd3ec | bellard | #define TCPTV_KEEPCNT 8 /* max probes before drop */ |
103 | f0cbd3ec | bellard | |
104 | f0cbd3ec | bellard | #define TCPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */ |
105 | f0cbd3ec | bellard | /* #define TCPTV_REXMTMAX ( 64*PR_SLOWHZ) */ /* max allowable REXMT value */ |
106 | f0cbd3ec | bellard | #define TCPTV_REXMTMAX ( 12*PR_SLOWHZ) /* max allowable REXMT value */ |
107 | f0cbd3ec | bellard | |
108 | f0cbd3ec | bellard | #define TCP_LINGERTIME 120 /* linger at most 2 minutes */ |
109 | f0cbd3ec | bellard | |
110 | f0cbd3ec | bellard | #define TCP_MAXRXTSHIFT 12 /* maximum retransmits */ |
111 | f0cbd3ec | bellard | |
112 | f0cbd3ec | bellard | |
113 | f0cbd3ec | bellard | #ifdef TCPTIMERS
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114 | f0cbd3ec | bellard | char *tcptimers[] =
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115 | f0cbd3ec | bellard | { "REXMT", "PERSIST", "KEEP", "2MSL" }; |
116 | f0cbd3ec | bellard | #endif
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117 | f0cbd3ec | bellard | |
118 | f0cbd3ec | bellard | /*
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119 | f0cbd3ec | bellard | * Force a time value to be in a certain range.
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120 | f0cbd3ec | bellard | */
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121 | f0cbd3ec | bellard | #define TCPT_RANGESET(tv, value, tvmin, tvmax) { \
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122 | f0cbd3ec | bellard | (tv) = (value); \ |
123 | f0cbd3ec | bellard | if ((tv) < (tvmin)) \
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124 | f0cbd3ec | bellard | (tv) = (tvmin); \ |
125 | f0cbd3ec | bellard | else if ((tv) > (tvmax)) \ |
126 | f0cbd3ec | bellard | (tv) = (tvmax); \ |
127 | f0cbd3ec | bellard | } |
128 | f0cbd3ec | bellard | |
129 | f0cbd3ec | bellard | extern int tcp_keepidle; /* time before keepalive probes begin */ |
130 | f0cbd3ec | bellard | extern int tcp_keepintvl; /* time between keepalive probes */ |
131 | f0cbd3ec | bellard | extern int tcp_maxidle; /* time to drop after starting probes */ |
132 | f0cbd3ec | bellard | extern int tcp_ttl; /* time to live for TCP segs */ |
133 | f0cbd3ec | bellard | extern int tcp_backoff[]; |
134 | f0cbd3ec | bellard | |
135 | f0cbd3ec | bellard | struct tcpcb;
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136 | f0cbd3ec | bellard | |
137 | f0cbd3ec | bellard | void tcp_fasttimo _P((void)); |
138 | f0cbd3ec | bellard | void tcp_slowtimo _P((void)); |
139 | f0cbd3ec | bellard | void tcp_canceltimers _P((struct tcpcb *)); |
140 | f0cbd3ec | bellard | struct tcpcb * tcp_timers _P((register struct tcpcb *, int)); |
141 | f0cbd3ec | bellard | |
142 | f0cbd3ec | bellard | #endif |