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1 | /* |
2 | * Copyright (c) 1982, 1986, 1988 Regents of the University of California. | |
3 | * 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 | * | |
136b31f1 | 33 | * from: @(#)spp_timer.h 7.3 (Berkeley) 6/28/90 |
8ace4366 | 34 | * $Id: spp_timer.h,v 1.2 1993/10/16 19:54:37 rgrimes Exp $ |
15637ed4 RG |
35 | */ |
36 | ||
8ace4366 GW |
37 | #ifndef _NETNS_SPP_TIMER_H_ |
38 | #define _NETNS_SPP_TIMER_H_ 1 | |
39 | ||
15637ed4 RG |
40 | /* |
41 | * Definitions of the SPP timers. These timers are counted | |
42 | * down PR_SLOWHZ times a second. | |
43 | */ | |
44 | #define SPPT_NTIMERS 4 | |
45 | ||
46 | #define SPPT_REXMT 0 /* retransmit */ | |
47 | #define SPPT_PERSIST 1 /* retransmit persistance */ | |
48 | #define SPPT_KEEP 2 /* keep alive */ | |
49 | #define SPPT_2MSL 3 /* 2*msl quiet time timer */ | |
50 | ||
51 | /* | |
52 | * The SPPT_REXMT timer is used to force retransmissions. | |
53 | * The SPP has the SPPT_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 SPPT_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 SPPT_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 SPPT_PERSMIN time intervals, | |
70 | * but no more frequently than the current estimate of round-trip | |
71 | * packet time. The SPPT_PERSIST timer is cleared whenever we receive | |
72 | * a window update from the peer. | |
73 | * | |
74 | * The SPPT_KEEP timer is used to keep connections alive. If an | |
75 | * connection is idle (no segments received) for SPPTV_KEEP amount of time, | |
76 | * but not yet established, then we drop the connection. If the connection | |
77 | * is established, then we force the peer to send us a segment by sending: | |
78 | * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK> | |
79 | * This segment is (deliberately) outside the window, and should elicit | |
80 | * an ack segment in response from the peer. If, despite the SPPT_KEEP | |
81 | * initiated segments we cannot elicit a response from a peer in SPPT_MAXIDLE | |
82 | * amount of time, then we drop the connection. | |
83 | */ | |
84 | ||
85 | #define SPP_TTL 30 /* default time to live for SPP segs */ | |
86 | /* | |
87 | * Time constants. | |
88 | */ | |
89 | #define SPPTV_MSL ( 15*PR_SLOWHZ) /* max seg lifetime */ | |
90 | #define SPPTV_SRTTBASE 0 /* base roundtrip time; | |
91 | if 0, no idea yet */ | |
92 | #define SPPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */ | |
93 | ||
94 | #define SPPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistance */ | |
95 | #define SPPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */ | |
96 | ||
97 | #define SPPTV_KEEP ( 75*PR_SLOWHZ) /* keep alive - 75 secs */ | |
98 | #define SPPTV_MAXIDLE ( 8*SPPTV_KEEP) /* maximum allowable idle | |
99 | time before drop conn */ | |
100 | ||
101 | #define SPPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */ | |
102 | #define SPPTV_REXMTMAX ( 64*PR_SLOWHZ) /* max allowable REXMT value */ | |
103 | ||
104 | #define SPP_LINGERTIME 120 /* linger at most 2 minutes */ | |
105 | ||
106 | #define SPP_MAXRXTSHIFT 12 /* maximum retransmits */ | |
107 | ||
108 | #ifdef SPPTIMERS | |
109 | char *spptimers[] = | |
110 | { "REXMT", "PERSIST", "KEEP", "2MSL" }; | |
111 | #endif | |
112 | ||
113 | /* | |
114 | * Force a time value to be in a certain range. | |
115 | */ | |
116 | #define SPPT_RANGESET(tv, value, tvmin, tvmax) { \ | |
117 | (tv) = (value); \ | |
118 | if ((tv) < (tvmin)) \ | |
119 | (tv) = (tvmin); \ | |
120 | else if ((tv) > (tvmax)) \ | |
121 | (tv) = (tvmax); \ | |
122 | } | |
123 | ||
124 | #ifdef KERNEL | |
125 | extern int spp_backoff[]; | |
126 | #endif | |
8ace4366 | 127 | #endif /* _NETNS_SPP_TIMER_H_ */ |