1 | /* |
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2 | * Copyright (c) 1982, 1986, 1988, 1993 |
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3 | * The Regents of the University of California. All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * 1. Redistributions of source code must retain the above copyright |
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9 | * notice, this list of conditions and the following disclaimer. |
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10 | * 2. Redistributions in binary form must reproduce the above copyright |
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11 | * notice, this list of conditions and the following disclaimer in the |
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12 | * documentation and/or other materials provided with the distribution. |
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13 | * 3. All advertising materials mentioning features or use of this software |
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14 | * must display the following acknowledgement: |
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15 | * This product includes software developed by the University of |
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16 | * California, Berkeley and its contributors. |
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17 | * 4. Neither the name of the University nor the names of its contributors |
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18 | * may be used to endorse or promote products derived from this software |
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19 | * without specific prior written permission. |
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20 | * |
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21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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31 | * SUCH DAMAGE. |
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32 | * |
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33 | * @(#)spp_timer.h 8.1 (Berkeley) 6/10/93 |
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34 | * $FreeBSD: src/sys/netns/spp_timer.h,v 1.9 1999/12/29 04:46:20 peter Exp $ |
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35 | */ |
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36 | |
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37 | #ifndef _NETNS_SPP_TIMER_H_ |
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38 | #define _NETNS_SPP_TIMER_H_ |
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39 | |
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40 | /* |
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41 | * Definitions of the SPP timers. These timers are counted |
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42 | * down PR_SLOWHZ times a second. |
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43 | */ |
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44 | #define SPPT_NTIMERS 4 |
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45 | |
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46 | #define SPPT_REXMT 0 /* retransmit */ |
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47 | #define SPPT_PERSIST 1 /* retransmit persistance */ |
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48 | #define SPPT_KEEP 2 /* keep alive */ |
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49 | #define SPPT_2MSL 3 /* 2*msl quiet time timer */ |
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50 | |
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51 | /* |
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52 | * The SPPT_REXMT timer is used to force retransmissions. |
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53 | * The SPP has the SPPT_REXMT timer set whenever segments |
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54 | * have been sent for which ACKs are expected but not yet |
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55 | * received. If an ACK is received which advances tp->snd_una, |
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56 | * then the retransmit timer is cleared (if there are no more |
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57 | * outstanding segments) or reset to the base value (if there |
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58 | * are more ACKs expected). Whenever the retransmit timer goes off, |
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59 | * we retransmit one unacknowledged segment, and do a backoff |
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60 | * on the retransmit timer. |
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61 | * |
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62 | * The SPPT_PERSIST timer is used to keep window size information |
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63 | * flowing even if the window goes shut. If all previous transmissions |
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64 | * have been acknowledged (so that there are no retransmissions in progress), |
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65 | * and the window is too small to bother sending anything, then we start |
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66 | * the SPPT_PERSIST timer. When it expires, if the window is nonzero, |
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67 | * we go to transmit state. Otherwise, at intervals send a single byte |
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68 | * into the peer's window to force him to update our window information. |
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69 | * We do this at most as often as SPPT_PERSMIN time intervals, |
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70 | * but no more frequently than the current estimate of round-trip |
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71 | * packet time. The SPPT_PERSIST timer is cleared whenever we receive |
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72 | * a window update from the peer. |
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73 | * |
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74 | * The SPPT_KEEP timer is used to keep connections alive. If an |
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75 | * connection is idle (no segments received) for SPPTV_KEEP amount of time, |
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76 | * but not yet established, then we drop the connection. If the connection |
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77 | * is established, then we force the peer to send us a segment by sending: |
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78 | * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK> |
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79 | * This segment is (deliberately) outside the window, and should elicit |
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80 | * an ack segment in response from the peer. If, despite the SPPT_KEEP |
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81 | * initiated segments we cannot elicit a response from a peer in SPPT_MAXIDLE |
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82 | * amount of time, then we drop the connection. |
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83 | */ |
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84 | |
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85 | #define SPP_TTL 30 /* default time to live for SPP segs */ |
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86 | /* |
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87 | * Time constants. |
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88 | */ |
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89 | #define SPPTV_MSL ( 15*PR_SLOWHZ) /* max seg lifetime */ |
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90 | #define SPPTV_SRTTBASE 0 /* base roundtrip time; |
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91 | if 0, no idea yet */ |
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92 | #define SPPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */ |
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93 | |
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94 | #define SPPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistance */ |
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95 | #define SPPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */ |
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96 | |
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97 | #define SPPTV_KEEP ( 75*PR_SLOWHZ) /* keep alive - 75 secs */ |
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98 | #define SPPTV_MAXIDLE ( 8*SPPTV_KEEP) /* maximum allowable idle |
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99 | time before drop conn */ |
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100 | |
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101 | #define SPPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */ |
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102 | #define SPPTV_REXMTMAX ( 64*PR_SLOWHZ) /* max allowable REXMT value */ |
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103 | |
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104 | #define SPP_LINGERTIME 120 /* linger at most 2 minutes */ |
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105 | |
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106 | #define SPP_MAXRXTSHIFT 12 /* maximum retransmits */ |
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107 | |
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108 | #ifdef SPPTIMERS |
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109 | char *spptimers[] = |
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110 | { "REXMT", "PERSIST", "KEEP", "2MSL" }; |
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111 | #endif |
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112 | |
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113 | /* |
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114 | * Force a time value to be in a certain range. |
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115 | */ |
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116 | #define SPPT_RANGESET(tv, value, tvmin, tvmax) { \ |
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117 | (tv) = (value); \ |
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118 | if ((tv) < (tvmin)) \ |
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119 | (tv) = (tvmin); \ |
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120 | else if ((tv) > (tvmax)) \ |
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121 | (tv) = (tvmax); \ |
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122 | } |
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123 | |
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124 | #ifdef _KERNEL |
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125 | extern int spp_backoff[]; |
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126 | #endif |
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127 | |
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128 | #endif |
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