1 | /*
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2 | * NTP client/server, based on OpenNTPD 3.9p1
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3 | *
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4 | * Busybox port author: Adam Tkac (C) 2009 <vonsch@gmail.com>
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5 | *
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6 | * OpenNTPd 3.9p1 copyright holders:
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7 | * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
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8 | * Copyright (c) 2004 Alexander Guy <alexander.guy@andern.org>
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9 | *
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10 | * OpenNTPd code is licensed under ISC-style licence:
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11 | *
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12 | * Permission to use, copy, modify, and distribute this software for any
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13 | * purpose with or without fee is hereby granted, provided that the above
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14 | * copyright notice and this permission notice appear in all copies.
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15 | *
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16 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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17 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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18 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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19 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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20 | * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
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21 | * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
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22 | * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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23 | ***********************************************************************
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24 | *
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25 | * Parts of OpenNTPD clock syncronization code is replaced by
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26 | * code which is based on ntp-4.2.6, which carries the following
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27 | * copyright notice:
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28 | *
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29 | * Copyright (c) University of Delaware 1992-2009
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30 | *
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31 | * Permission to use, copy, modify, and distribute this software and
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32 | * its documentation for any purpose with or without fee is hereby
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33 | * granted, provided that the above copyright notice appears in all
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34 | * copies and that both the copyright notice and this permission
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35 | * notice appear in supporting documentation, and that the name
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36 | * University of Delaware not be used in advertising or publicity
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37 | * pertaining to distribution of the software without specific,
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38 | * written prior permission. The University of Delaware makes no
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39 | * representations about the suitability this software for any
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40 | * purpose. It is provided "as is" without express or implied warranty.
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41 | ***********************************************************************
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42 | */
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43 |
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44 | //usage:#define ntpd_trivial_usage
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45 | //usage: "[-dnqNw"IF_FEATURE_NTPD_SERVER("l -I IFACE")"] [-S PROG] [-p PEER]..."
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46 | //usage:#define ntpd_full_usage "\n\n"
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47 | //usage: "NTP client/server\n"
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48 | //usage: "\n -d Verbose"
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49 | //usage: "\n -n Do not daemonize"
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50 | //usage: "\n -q Quit after clock is set"
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51 | //usage: "\n -N Run at high priority"
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52 | //usage: "\n -w Do not set time (only query peers), implies -n"
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53 | //usage: "\n -S PROG Run PROG after stepping time, stratum change, and every 11 mins"
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54 | //usage: "\n -p PEER Obtain time from PEER (may be repeated)"
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55 | //usage: IF_FEATURE_NTPD_CONF(
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56 | //usage: "\n If -p is not given, 'server HOST' lines"
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57 | //usage: "\n from /etc/ntp.conf are used"
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58 | //usage: )
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59 | //usage: IF_FEATURE_NTPD_SERVER(
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60 | //usage: "\n -l Also run as server on port 123"
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61 | //usage: "\n -I IFACE Bind server to IFACE, implies -l"
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62 | //usage: )
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63 |
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64 | // -l and -p options are not compatible with "standard" ntpd:
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65 | // it has them as "-l logfile" and "-p pidfile".
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66 | // -S and -w are not compat either, "standard" ntpd has no such opts.
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67 |
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68 | #include "libbb.h"
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69 | #include <math.h>
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70 | #include <netinet/ip.h> /* For IPTOS_LOWDELAY definition */
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71 | #include <sys/resource.h> /* setpriority */
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72 | #include <sys/timex.h>
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73 | #ifndef IPTOS_LOWDELAY
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74 | # define IPTOS_LOWDELAY 0x10
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75 | #endif
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76 |
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77 |
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78 | /* Verbosity control (max level of -dddd options accepted).
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79 | * max 6 is very talkative (and bloated). 3 is non-bloated,
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80 | * production level setting.
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81 | */
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82 | #define MAX_VERBOSE 3
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83 |
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84 |
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85 | /* High-level description of the algorithm:
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86 | *
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87 | * We start running with very small poll_exp, BURSTPOLL,
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88 | * in order to quickly accumulate INITIAL_SAMPLES datapoints
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89 | * for each peer. Then, time is stepped if the offset is larger
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90 | * than STEP_THRESHOLD, otherwise it isn't; anyway, we enlarge
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91 | * poll_exp to MINPOLL and enter frequency measurement step:
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92 | * we collect new datapoints but ignore them for WATCH_THRESHOLD
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93 | * seconds. After WATCH_THRESHOLD seconds we look at accumulated
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94 | * offset and estimate frequency drift.
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95 | *
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96 | * (frequency measurement step seems to not be strictly needed,
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97 | * it is conditionally disabled with USING_INITIAL_FREQ_ESTIMATION
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98 | * define set to 0)
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99 | *
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100 | * After this, we enter "steady state": we collect a datapoint,
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101 | * we select the best peer, if this datapoint is not a new one
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102 | * (IOW: if this datapoint isn't for selected peer), sleep
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103 | * and collect another one; otherwise, use its offset to update
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104 | * frequency drift, if offset is somewhat large, reduce poll_exp,
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105 | * otherwise increase poll_exp.
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106 | *
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107 | * If offset is larger than STEP_THRESHOLD, which shouldn't normally
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108 | * happen, we assume that something "bad" happened (computer
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109 | * was hibernated, someone set totally wrong date, etc),
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110 | * then the time is stepped, all datapoints are discarded,
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111 | * and we go back to steady state.
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112 | *
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113 | * Made some changes to speed up re-syncing after our clock goes bad
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114 | * (tested with suspending my laptop):
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115 | * - if largish offset (>= STEP_THRESHOLD == 1 sec) is seen
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116 | * from a peer, schedule next query for this peer soon
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117 | * without drastically lowering poll interval for everybody.
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118 | * This makes us collect enough data for step much faster:
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119 | * e.g. at poll = 10 (1024 secs), step was done within 5 minutes
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120 | * after first reply which indicated that our clock is 14 seconds off.
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121 | * - on step, do not discard d_dispersion data of the existing datapoints,
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122 | * do not clear reachable_bits. This prevents discarding first ~8
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123 | * datapoints after the step.
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124 | */
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125 |
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126 | #define INITIAL_SAMPLES 4 /* how many samples do we want for init */
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127 | #define BAD_DELAY_GROWTH 4 /* drop packet if its delay grew by more than this */
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128 |
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129 | #define RETRY_INTERVAL 32 /* on send/recv error, retry in N secs (need to be power of 2) */
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130 | #define NOREPLY_INTERVAL 512 /* sent, but got no reply: cap next query by this many seconds */
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131 | #define RESPONSE_INTERVAL 16 /* wait for reply up to N secs */
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132 |
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133 | /* Step threshold (sec). std ntpd uses 0.128.
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134 | */
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135 | #define STEP_THRESHOLD 1
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136 | /* Slew threshold (sec): adjtimex() won't accept offsets larger than this.
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137 | * Using exact power of 2 (1/8) results in smaller code
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138 | */
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139 | #define SLEW_THRESHOLD 0.125
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140 | /* Stepout threshold (sec). std ntpd uses 900 (11 mins (!)) */
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141 | #define WATCH_THRESHOLD 128
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142 | /* NB: set WATCH_THRESHOLD to ~60 when debugging to save time) */
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143 | //UNUSED: #define PANIC_THRESHOLD 1000 /* panic threshold (sec) */
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144 |
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145 | /*
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146 | * If we got |offset| > BIGOFF from a peer, cap next query interval
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147 | * for this peer by this many seconds:
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148 | */
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149 | #define BIGOFF STEP_THRESHOLD
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150 | #define BIGOFF_INTERVAL (1 << 7) /* 128 s */
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151 |
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152 | #define FREQ_TOLERANCE 0.000015 /* frequency tolerance (15 PPM) */
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153 | #define BURSTPOLL 0 /* initial poll */
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154 | #define MINPOLL 5 /* minimum poll interval. std ntpd uses 6 (6: 64 sec) */
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155 | /*
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156 | * If offset > discipline_jitter * POLLADJ_GATE, and poll interval is > 2^BIGPOLL,
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157 | * then it is decreased _at once_. (If <= 2^BIGPOLL, it will be decreased _eventually_).
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158 | */
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159 | #define BIGPOLL 9 /* 2^9 sec ~= 8.5 min */
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160 | #define MAXPOLL 12 /* maximum poll interval (12: 1.1h, 17: 36.4h). std ntpd uses 17 */
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161 | /*
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162 | * Actively lower poll when we see such big offsets.
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163 | * With SLEW_THRESHOLD = 0.125, it means we try to sync more aggressively
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164 | * if offset increases over ~0.04 sec
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165 | */
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166 | //#define POLLDOWN_OFFSET (SLEW_THRESHOLD / 3)
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167 | #define MINDISP 0.01 /* minimum dispersion (sec) */
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168 | #define MAXDISP 16 /* maximum dispersion (sec) */
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169 | #define MAXSTRAT 16 /* maximum stratum (infinity metric) */
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170 | #define MAXDIST 1 /* distance threshold (sec) */
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171 | #define MIN_SELECTED 1 /* minimum intersection survivors */
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172 | #define MIN_CLUSTERED 3 /* minimum cluster survivors */
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173 |
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174 | #define MAXDRIFT 0.000500 /* frequency drift we can correct (500 PPM) */
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175 |
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176 | /* Poll-adjust threshold.
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177 | * When we see that offset is small enough compared to discipline jitter,
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178 | * we grow a counter: += MINPOLL. When counter goes over POLLADJ_LIMIT,
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179 | * we poll_exp++. If offset isn't small, counter -= poll_exp*2,
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180 | * and when it goes below -POLLADJ_LIMIT, we poll_exp--.
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181 | * (Bumped from 30 to 40 since otherwise I often see poll_exp going *2* steps down)
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182 | */
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183 | #define POLLADJ_LIMIT 40
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184 | /* If offset < discipline_jitter * POLLADJ_GATE, then we decide to increase
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185 | * poll interval (we think we can't improve timekeeping
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186 | * by staying at smaller poll).
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187 | */
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188 | #define POLLADJ_GATE 4
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189 | #define TIMECONST_HACK_GATE 2
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190 | /* Compromise Allan intercept (sec). doc uses 1500, std ntpd uses 512 */
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191 | #define ALLAN 512
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192 | /* PLL loop gain */
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193 | #define PLL 65536
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194 | /* FLL loop gain [why it depends on MAXPOLL??] */
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195 | #define FLL (MAXPOLL + 1)
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196 | /* Parameter averaging constant */
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197 | #define AVG 4
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198 |
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199 |
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200 | enum {
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201 | NTP_VERSION = 4,
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202 | NTP_MAXSTRATUM = 15,
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203 |
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204 | NTP_DIGESTSIZE = 16,
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205 | NTP_MSGSIZE_NOAUTH = 48,
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206 | NTP_MSGSIZE = (NTP_MSGSIZE_NOAUTH + 4 + NTP_DIGESTSIZE),
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207 |
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208 | /* Status Masks */
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209 | MODE_MASK = (7 << 0),
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210 | VERSION_MASK = (7 << 3),
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211 | VERSION_SHIFT = 3,
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212 | LI_MASK = (3 << 6),
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213 |
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214 | /* Leap Second Codes (high order two bits of m_status) */
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215 | LI_NOWARNING = (0 << 6), /* no warning */
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216 | LI_PLUSSEC = (1 << 6), /* add a second (61 seconds) */
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217 | LI_MINUSSEC = (2 << 6), /* minus a second (59 seconds) */
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218 | LI_ALARM = (3 << 6), /* alarm condition */
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219 |
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220 | /* Mode values */
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221 | MODE_RES0 = 0, /* reserved */
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222 | MODE_SYM_ACT = 1, /* symmetric active */
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223 | MODE_SYM_PAS = 2, /* symmetric passive */
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224 | MODE_CLIENT = 3, /* client */
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225 | MODE_SERVER = 4, /* server */
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226 | MODE_BROADCAST = 5, /* broadcast */
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227 | MODE_RES1 = 6, /* reserved for NTP control message */
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228 | MODE_RES2 = 7, /* reserved for private use */
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229 | };
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230 |
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231 | //TODO: better base selection
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232 | #define OFFSET_1900_1970 2208988800UL /* 1970 - 1900 in seconds */
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233 |
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234 | #define NUM_DATAPOINTS 8
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235 |
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236 | typedef struct {
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237 | uint32_t int_partl;
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238 | uint32_t fractionl;
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239 | } l_fixedpt_t;
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240 |
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241 | typedef struct {
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242 | uint16_t int_parts;
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243 | uint16_t fractions;
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244 | } s_fixedpt_t;
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245 |
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246 | typedef struct {
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247 | uint8_t m_status; /* status of local clock and leap info */
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248 | uint8_t m_stratum;
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249 | uint8_t m_ppoll; /* poll value */
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250 | int8_t m_precision_exp;
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251 | s_fixedpt_t m_rootdelay;
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252 | s_fixedpt_t m_rootdisp;
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253 | uint32_t m_refid;
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254 | l_fixedpt_t m_reftime;
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255 | l_fixedpt_t m_orgtime;
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256 | l_fixedpt_t m_rectime;
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257 | l_fixedpt_t m_xmttime;
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258 | uint32_t m_keyid;
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259 | uint8_t m_digest[NTP_DIGESTSIZE];
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260 | } msg_t;
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261 |
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262 | typedef struct {
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263 | double d_offset;
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264 | double d_recv_time;
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265 | double d_dispersion;
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266 | } datapoint_t;
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267 |
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268 | typedef struct {
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269 | len_and_sockaddr *p_lsa;
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270 | char *p_dotted;
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271 | int p_fd;
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272 | int datapoint_idx;
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273 | uint32_t lastpkt_refid;
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274 | uint8_t lastpkt_status;
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275 | uint8_t lastpkt_stratum;
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276 | uint8_t reachable_bits;
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277 | /* when to send new query (if p_fd == -1)
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278 | * or when receive times out (if p_fd >= 0): */
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279 | double next_action_time;
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280 | double p_xmttime;
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281 | double p_raw_delay;
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282 | /* p_raw_delay is set even by "high delay" packets */
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283 | /* lastpkt_delay isn't */
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284 | double lastpkt_recv_time;
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285 | double lastpkt_delay;
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286 | double lastpkt_rootdelay;
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287 | double lastpkt_rootdisp;
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288 | /* produced by filter algorithm: */
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289 | double filter_offset;
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290 | double filter_dispersion;
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291 | double filter_jitter;
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292 | datapoint_t filter_datapoint[NUM_DATAPOINTS];
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293 | /* last sent packet: */
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294 | msg_t p_xmt_msg;
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295 | char p_hostname[1];
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296 | } peer_t;
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297 |
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298 |
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299 | #define USING_KERNEL_PLL_LOOP 1
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300 | #define USING_INITIAL_FREQ_ESTIMATION 0
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301 |
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302 | enum {
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303 | OPT_n = (1 << 0),
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304 | OPT_q = (1 << 1),
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305 | OPT_N = (1 << 2),
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306 | OPT_x = (1 << 3),
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307 | /* Insert new options above this line. */
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308 | /* Non-compat options: */
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309 | OPT_w = (1 << 4),
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310 | OPT_p = (1 << 5),
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311 | OPT_S = (1 << 6),
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312 | OPT_l = (1 << 7) * ENABLE_FEATURE_NTPD_SERVER,
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313 | OPT_I = (1 << 8) * ENABLE_FEATURE_NTPD_SERVER,
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314 | /* We hijack some bits for other purposes */
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315 | OPT_qq = (1 << 31),
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316 | };
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317 |
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318 | struct globals {
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319 | double cur_time;
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320 | /* total round trip delay to currently selected reference clock */
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321 | double rootdelay;
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322 | /* reference timestamp: time when the system clock was last set or corrected */
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323 | double reftime;
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324 | /* total dispersion to currently selected reference clock */
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325 | double rootdisp;
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326 |
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327 | double last_script_run;
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328 | char *script_name;
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329 | llist_t *ntp_peers;
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330 | #if ENABLE_FEATURE_NTPD_SERVER
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331 | int listen_fd;
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332 | char *if_name;
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333 | # define G_listen_fd (G.listen_fd)
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334 | #else
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335 | # define G_listen_fd (-1)
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336 | #endif
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337 | unsigned verbose;
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338 | unsigned peer_cnt;
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339 | /* refid: 32-bit code identifying the particular server or reference clock
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340 | * in stratum 0 packets this is a four-character ASCII string,
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341 | * called the kiss code, used for debugging and monitoring
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342 | * in stratum 1 packets this is a four-character ASCII string
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343 | * assigned to the reference clock by IANA. Example: "GPS "
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344 | * in stratum 2+ packets, it's IPv4 address or 4 first bytes
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345 | * of MD5 hash of IPv6
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346 | */
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347 | uint32_t refid;
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348 | uint8_t ntp_status;
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349 | /* precision is defined as the larger of the resolution and time to
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350 | * read the clock, in log2 units. For instance, the precision of a
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351 | * mains-frequency clock incrementing at 60 Hz is 16 ms, even when the
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352 | * system clock hardware representation is to the nanosecond.
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353 | *
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354 | * Delays, jitters of various kinds are clamped down to precision.
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355 | *
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356 | * If precision_sec is too large, discipline_jitter gets clamped to it
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357 | * and if offset is smaller than discipline_jitter * POLLADJ_GATE, poll
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358 | * interval grows even though we really can benefit from staying at
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359 | * smaller one, collecting non-lagged datapoits and correcting offset.
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360 | * (Lagged datapoits exist when poll_exp is large but we still have
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361 | * systematic offset error - the time distance between datapoints
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362 | * is significant and older datapoints have smaller offsets.
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363 | * This makes our offset estimation a bit smaller than reality)
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364 | * Due to this effect, setting G_precision_sec close to
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365 | * STEP_THRESHOLD isn't such a good idea - offsets may grow
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366 | * too big and we will step. I observed it with -6.
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367 | *
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368 | * OTOH, setting precision_sec far too small would result in futile
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369 | * attempts to syncronize to an unachievable precision.
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370 | *
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371 | * -6 is 1/64 sec, -7 is 1/128 sec and so on.
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372 | * -8 is 1/256 ~= 0.003906 (worked well for me --vda)
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373 | * -9 is 1/512 ~= 0.001953 (let's try this for some time)
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374 | */
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375 | #define G_precision_exp -9
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376 | /*
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377 | * G_precision_exp is used only for construction outgoing packets.
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378 | * It's ok to set G_precision_sec to a slightly different value
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379 | * (One which is "nicer looking" in logs).
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380 | * Exact value would be (1.0 / (1 << (- G_precision_exp))):
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381 | */
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382 | #define G_precision_sec 0.002
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383 | uint8_t stratum;
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384 |
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385 | #define STATE_NSET 0 /* initial state, "nothing is set" */
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386 | //#define STATE_FSET 1 /* frequency set from file */
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387 | //#define STATE_SPIK 2 /* spike detected */
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388 | //#define STATE_FREQ 3 /* initial frequency */
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389 | #define STATE_SYNC 4 /* clock synchronized (normal operation) */
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390 | uint8_t discipline_state; // doc calls it c.state
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391 | uint8_t poll_exp; // s.poll
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392 | int polladj_count; // c.count
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393 | long kernel_freq_drift;
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394 | peer_t *last_update_peer;
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395 | double last_update_offset; // c.last
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396 | double last_update_recv_time; // s.t
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397 | double discipline_jitter; // c.jitter
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398 | /* Since we only compare it with ints, can simplify code
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399 | * by not making this variable floating point:
|
---|
400 | */
|
---|
401 | unsigned offset_to_jitter_ratio;
|
---|
402 | //double cluster_offset; // s.offset
|
---|
403 | //double cluster_jitter; // s.jitter
|
---|
404 | #if !USING_KERNEL_PLL_LOOP
|
---|
405 | double discipline_freq_drift; // c.freq
|
---|
406 | /* Maybe conditionally calculate wander? it's used only for logging */
|
---|
407 | double discipline_wander; // c.wander
|
---|
408 | #endif
|
---|
409 | };
|
---|
410 | #define G (*ptr_to_globals)
|
---|
411 |
|
---|
412 |
|
---|
413 | #define VERB1 if (MAX_VERBOSE && G.verbose)
|
---|
414 | #define VERB2 if (MAX_VERBOSE >= 2 && G.verbose >= 2)
|
---|
415 | #define VERB3 if (MAX_VERBOSE >= 3 && G.verbose >= 3)
|
---|
416 | #define VERB4 if (MAX_VERBOSE >= 4 && G.verbose >= 4)
|
---|
417 | #define VERB5 if (MAX_VERBOSE >= 5 && G.verbose >= 5)
|
---|
418 | #define VERB6 if (MAX_VERBOSE >= 6 && G.verbose >= 6)
|
---|
419 |
|
---|
420 |
|
---|
421 | static double LOG2D(int a)
|
---|
422 | {
|
---|
423 | if (a < 0)
|
---|
424 | return 1.0 / (1UL << -a);
|
---|
425 | return 1UL << a;
|
---|
426 | }
|
---|
427 | static ALWAYS_INLINE double SQUARE(double x)
|
---|
428 | {
|
---|
429 | return x * x;
|
---|
430 | }
|
---|
431 | static ALWAYS_INLINE double MAXD(double a, double b)
|
---|
432 | {
|
---|
433 | if (a > b)
|
---|
434 | return a;
|
---|
435 | return b;
|
---|
436 | }
|
---|
437 | static ALWAYS_INLINE double MIND(double a, double b)
|
---|
438 | {
|
---|
439 | if (a < b)
|
---|
440 | return a;
|
---|
441 | return b;
|
---|
442 | }
|
---|
443 | static NOINLINE double my_SQRT(double X)
|
---|
444 | {
|
---|
445 | union {
|
---|
446 | float f;
|
---|
447 | int32_t i;
|
---|
448 | } v;
|
---|
449 | double invsqrt;
|
---|
450 | double Xhalf = X * 0.5;
|
---|
451 |
|
---|
452 | /* Fast and good approximation to 1/sqrt(X), black magic */
|
---|
453 | v.f = X;
|
---|
454 | /*v.i = 0x5f3759df - (v.i >> 1);*/
|
---|
455 | v.i = 0x5f375a86 - (v.i >> 1); /* - this constant is slightly better */
|
---|
456 | invsqrt = v.f; /* better than 0.2% accuracy */
|
---|
457 |
|
---|
458 | /* Refining it using Newton's method: x1 = x0 - f(x0)/f'(x0)
|
---|
459 | * f(x) = 1/(x*x) - X (f==0 when x = 1/sqrt(X))
|
---|
460 | * f'(x) = -2/(x*x*x)
|
---|
461 | * f(x)/f'(x) = (X - 1/(x*x)) / (2/(x*x*x)) = X*x*x*x/2 - x/2
|
---|
462 | * x1 = x0 - (X*x0*x0*x0/2 - x0/2) = 1.5*x0 - X*x0*x0*x0/2 = x0*(1.5 - (X/2)*x0*x0)
|
---|
463 | */
|
---|
464 | invsqrt = invsqrt * (1.5 - Xhalf * invsqrt * invsqrt); /* ~0.05% accuracy */
|
---|
465 | /* invsqrt = invsqrt * (1.5 - Xhalf * invsqrt * invsqrt); 2nd iter: ~0.0001% accuracy */
|
---|
466 | /* With 4 iterations, more than half results will be exact,
|
---|
467 | * at 6th iterations result stabilizes with about 72% results exact.
|
---|
468 | * We are well satisfied with 0.05% accuracy.
|
---|
469 | */
|
---|
470 |
|
---|
471 | return X * invsqrt; /* X * 1/sqrt(X) ~= sqrt(X) */
|
---|
472 | }
|
---|
473 | static ALWAYS_INLINE double SQRT(double X)
|
---|
474 | {
|
---|
475 | /* If this arch doesn't use IEEE 754 floats, fall back to using libm */
|
---|
476 | if (sizeof(float) != 4)
|
---|
477 | return sqrt(X);
|
---|
478 |
|
---|
479 | /* This avoids needing libm, saves about 0.5k on x86-32 */
|
---|
480 | return my_SQRT(X);
|
---|
481 | }
|
---|
482 |
|
---|
483 | static double
|
---|
484 | gettime1900d(void)
|
---|
485 | {
|
---|
486 | struct timeval tv;
|
---|
487 | gettimeofday(&tv, NULL); /* never fails */
|
---|
488 | G.cur_time = tv.tv_sec + (1.0e-6 * tv.tv_usec) + OFFSET_1900_1970;
|
---|
489 | return G.cur_time;
|
---|
490 | }
|
---|
491 |
|
---|
492 | static void
|
---|
493 | d_to_tv(double d, struct timeval *tv)
|
---|
494 | {
|
---|
495 | tv->tv_sec = (long)d;
|
---|
496 | tv->tv_usec = (d - tv->tv_sec) * 1000000;
|
---|
497 | }
|
---|
498 |
|
---|
499 | static double
|
---|
500 | lfp_to_d(l_fixedpt_t lfp)
|
---|
501 | {
|
---|
502 | double ret;
|
---|
503 | lfp.int_partl = ntohl(lfp.int_partl);
|
---|
504 | lfp.fractionl = ntohl(lfp.fractionl);
|
---|
505 | ret = (double)lfp.int_partl + ((double)lfp.fractionl / UINT_MAX);
|
---|
506 | return ret;
|
---|
507 | }
|
---|
508 | static double
|
---|
509 | sfp_to_d(s_fixedpt_t sfp)
|
---|
510 | {
|
---|
511 | double ret;
|
---|
512 | sfp.int_parts = ntohs(sfp.int_parts);
|
---|
513 | sfp.fractions = ntohs(sfp.fractions);
|
---|
514 | ret = (double)sfp.int_parts + ((double)sfp.fractions / USHRT_MAX);
|
---|
515 | return ret;
|
---|
516 | }
|
---|
517 | #if ENABLE_FEATURE_NTPD_SERVER
|
---|
518 | static l_fixedpt_t
|
---|
519 | d_to_lfp(double d)
|
---|
520 | {
|
---|
521 | l_fixedpt_t lfp;
|
---|
522 | lfp.int_partl = (uint32_t)d;
|
---|
523 | lfp.fractionl = (uint32_t)((d - lfp.int_partl) * UINT_MAX);
|
---|
524 | lfp.int_partl = htonl(lfp.int_partl);
|
---|
525 | lfp.fractionl = htonl(lfp.fractionl);
|
---|
526 | return lfp;
|
---|
527 | }
|
---|
528 | static s_fixedpt_t
|
---|
529 | d_to_sfp(double d)
|
---|
530 | {
|
---|
531 | s_fixedpt_t sfp;
|
---|
532 | sfp.int_parts = (uint16_t)d;
|
---|
533 | sfp.fractions = (uint16_t)((d - sfp.int_parts) * USHRT_MAX);
|
---|
534 | sfp.int_parts = htons(sfp.int_parts);
|
---|
535 | sfp.fractions = htons(sfp.fractions);
|
---|
536 | return sfp;
|
---|
537 | }
|
---|
538 | #endif
|
---|
539 |
|
---|
540 | static double
|
---|
541 | dispersion(const datapoint_t *dp)
|
---|
542 | {
|
---|
543 | return dp->d_dispersion + FREQ_TOLERANCE * (G.cur_time - dp->d_recv_time);
|
---|
544 | }
|
---|
545 |
|
---|
546 | static double
|
---|
547 | root_distance(peer_t *p)
|
---|
548 | {
|
---|
549 | /* The root synchronization distance is the maximum error due to
|
---|
550 | * all causes of the local clock relative to the primary server.
|
---|
551 | * It is defined as half the total delay plus total dispersion
|
---|
552 | * plus peer jitter.
|
---|
553 | */
|
---|
554 | return MAXD(MINDISP, p->lastpkt_rootdelay + p->lastpkt_delay) / 2
|
---|
555 | + p->lastpkt_rootdisp
|
---|
556 | + p->filter_dispersion
|
---|
557 | + FREQ_TOLERANCE * (G.cur_time - p->lastpkt_recv_time)
|
---|
558 | + p->filter_jitter;
|
---|
559 | }
|
---|
560 |
|
---|
561 | static void
|
---|
562 | set_next(peer_t *p, unsigned t)
|
---|
563 | {
|
---|
564 | p->next_action_time = G.cur_time + t;
|
---|
565 | }
|
---|
566 |
|
---|
567 | /*
|
---|
568 | * Peer clock filter and its helpers
|
---|
569 | */
|
---|
570 | static void
|
---|
571 | filter_datapoints(peer_t *p)
|
---|
572 | {
|
---|
573 | int i, idx;
|
---|
574 | double sum, wavg;
|
---|
575 | datapoint_t *fdp;
|
---|
576 |
|
---|
577 | #if 0
|
---|
578 | /* Simulations have shown that use of *averaged* offset for p->filter_offset
|
---|
579 | * is in fact worse than simply using last received one: with large poll intervals
|
---|
580 | * (>= 2048) averaging code uses offset values which are outdated by hours,
|
---|
581 | * and time/frequency correction goes totally wrong when fed essentially bogus offsets.
|
---|
582 | */
|
---|
583 | int got_newest;
|
---|
584 | double minoff, maxoff, w;
|
---|
585 | double x = x; /* for compiler */
|
---|
586 | double oldest_off = oldest_off;
|
---|
587 | double oldest_age = oldest_age;
|
---|
588 | double newest_off = newest_off;
|
---|
589 | double newest_age = newest_age;
|
---|
590 |
|
---|
591 | fdp = p->filter_datapoint;
|
---|
592 |
|
---|
593 | minoff = maxoff = fdp[0].d_offset;
|
---|
594 | for (i = 1; i < NUM_DATAPOINTS; i++) {
|
---|
595 | if (minoff > fdp[i].d_offset)
|
---|
596 | minoff = fdp[i].d_offset;
|
---|
597 | if (maxoff < fdp[i].d_offset)
|
---|
598 | maxoff = fdp[i].d_offset;
|
---|
599 | }
|
---|
600 |
|
---|
601 | idx = p->datapoint_idx; /* most recent datapoint's index */
|
---|
602 | /* Average offset:
|
---|
603 | * Drop two outliers and take weighted average of the rest:
|
---|
604 | * most_recent/2 + older1/4 + older2/8 ... + older5/32 + older6/32
|
---|
605 | * we use older6/32, not older6/64 since sum of weights should be 1:
|
---|
606 | * 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/32 = 1
|
---|
607 | */
|
---|
608 | wavg = 0;
|
---|
609 | w = 0.5;
|
---|
610 | /* n-1
|
---|
611 | * --- dispersion(i)
|
---|
612 | * filter_dispersion = \ -------------
|
---|
613 | * / (i+1)
|
---|
614 | * --- 2
|
---|
615 | * i=0
|
---|
616 | */
|
---|
617 | got_newest = 0;
|
---|
618 | sum = 0;
|
---|
619 | for (i = 0; i < NUM_DATAPOINTS; i++) {
|
---|
620 | VERB5 {
|
---|
621 | bb_error_msg("datapoint[%d]: off:%f disp:%f(%f) age:%f%s",
|
---|
622 | i,
|
---|
623 | fdp[idx].d_offset,
|
---|
624 | fdp[idx].d_dispersion, dispersion(&fdp[idx]),
|
---|
625 | G.cur_time - fdp[idx].d_recv_time,
|
---|
626 | (minoff == fdp[idx].d_offset || maxoff == fdp[idx].d_offset)
|
---|
627 | ? " (outlier by offset)" : ""
|
---|
628 | );
|
---|
629 | }
|
---|
630 |
|
---|
631 | sum += dispersion(&fdp[idx]) / (2 << i);
|
---|
632 |
|
---|
633 | if (minoff == fdp[idx].d_offset) {
|
---|
634 | minoff -= 1; /* so that we don't match it ever again */
|
---|
635 | } else
|
---|
636 | if (maxoff == fdp[idx].d_offset) {
|
---|
637 | maxoff += 1;
|
---|
638 | } else {
|
---|
639 | oldest_off = fdp[idx].d_offset;
|
---|
640 | oldest_age = G.cur_time - fdp[idx].d_recv_time;
|
---|
641 | if (!got_newest) {
|
---|
642 | got_newest = 1;
|
---|
643 | newest_off = oldest_off;
|
---|
644 | newest_age = oldest_age;
|
---|
645 | }
|
---|
646 | x = oldest_off * w;
|
---|
647 | wavg += x;
|
---|
648 | w /= 2;
|
---|
649 | }
|
---|
650 |
|
---|
651 | idx = (idx - 1) & (NUM_DATAPOINTS - 1);
|
---|
652 | }
|
---|
653 | p->filter_dispersion = sum;
|
---|
654 | wavg += x; /* add another older6/64 to form older6/32 */
|
---|
655 | /* Fix systematic underestimation with large poll intervals.
|
---|
656 | * Imagine that we still have a bit of uncorrected drift,
|
---|
657 | * and poll interval is big (say, 100 sec). Offsets form a progression:
|
---|
658 | * 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 - 0.7 is most recent.
|
---|
659 | * The algorithm above drops 0.0 and 0.7 as outliers,
|
---|
660 | * and then we have this estimation, ~25% off from 0.7:
|
---|
661 | * 0.1/32 + 0.2/32 + 0.3/16 + 0.4/8 + 0.5/4 + 0.6/2 = 0.503125
|
---|
662 | */
|
---|
663 | x = oldest_age - newest_age;
|
---|
664 | if (x != 0) {
|
---|
665 | x = newest_age / x; /* in above example, 100 / (600 - 100) */
|
---|
666 | if (x < 1) { /* paranoia check */
|
---|
667 | x = (newest_off - oldest_off) * x; /* 0.5 * 100/500 = 0.1 */
|
---|
668 | wavg += x;
|
---|
669 | }
|
---|
670 | }
|
---|
671 | p->filter_offset = wavg;
|
---|
672 |
|
---|
673 | #else
|
---|
674 |
|
---|
675 | fdp = p->filter_datapoint;
|
---|
676 | idx = p->datapoint_idx; /* most recent datapoint's index */
|
---|
677 |
|
---|
678 | /* filter_offset: simply use the most recent value */
|
---|
679 | p->filter_offset = fdp[idx].d_offset;
|
---|
680 |
|
---|
681 | /* n-1
|
---|
682 | * --- dispersion(i)
|
---|
683 | * filter_dispersion = \ -------------
|
---|
684 | * / (i+1)
|
---|
685 | * --- 2
|
---|
686 | * i=0
|
---|
687 | */
|
---|
688 | wavg = 0;
|
---|
689 | sum = 0;
|
---|
690 | for (i = 0; i < NUM_DATAPOINTS; i++) {
|
---|
691 | sum += dispersion(&fdp[idx]) / (2 << i);
|
---|
692 | wavg += fdp[idx].d_offset;
|
---|
693 | idx = (idx - 1) & (NUM_DATAPOINTS - 1);
|
---|
694 | }
|
---|
695 | wavg /= NUM_DATAPOINTS;
|
---|
696 | p->filter_dispersion = sum;
|
---|
697 | #endif
|
---|
698 |
|
---|
699 | /* +----- -----+ ^ 1/2
|
---|
700 | * | n-1 |
|
---|
701 | * | --- |
|
---|
702 | * | 1 \ 2 |
|
---|
703 | * filter_jitter = | --- * / (avg-offset_j) |
|
---|
704 | * | n --- |
|
---|
705 | * | j=0 |
|
---|
706 | * +----- -----+
|
---|
707 | * where n is the number of valid datapoints in the filter (n > 1);
|
---|
708 | * if filter_jitter < precision then filter_jitter = precision
|
---|
709 | */
|
---|
710 | sum = 0;
|
---|
711 | for (i = 0; i < NUM_DATAPOINTS; i++) {
|
---|
712 | sum += SQUARE(wavg - fdp[i].d_offset);
|
---|
713 | }
|
---|
714 | sum = SQRT(sum / NUM_DATAPOINTS);
|
---|
715 | p->filter_jitter = sum > G_precision_sec ? sum : G_precision_sec;
|
---|
716 |
|
---|
717 | VERB4 bb_error_msg("filter offset:%+f disp:%f jitter:%f",
|
---|
718 | p->filter_offset,
|
---|
719 | p->filter_dispersion,
|
---|
720 | p->filter_jitter);
|
---|
721 | }
|
---|
722 |
|
---|
723 | static void
|
---|
724 | reset_peer_stats(peer_t *p, double offset)
|
---|
725 | {
|
---|
726 | int i;
|
---|
727 | bool small_ofs = fabs(offset) < STEP_THRESHOLD;
|
---|
728 |
|
---|
729 | /* Used to set p->filter_datapoint[i].d_dispersion = MAXDISP
|
---|
730 | * and clear reachable bits, but this proved to be too agressive:
|
---|
731 | * after step (tested with suspending laptop for ~30 secs),
|
---|
732 | * this caused all previous data to be considered invalid,
|
---|
733 | * making us needing to collect full ~8 datapoins per peer
|
---|
734 | * after step in order to start trusting them.
|
---|
735 | * In turn, this was making poll interval decrease even after
|
---|
736 | * step was done. (Poll interval decreases already before step
|
---|
737 | * in this scenario, because we see large offsets and end up with
|
---|
738 | * no good peer to select).
|
---|
739 | */
|
---|
740 |
|
---|
741 | for (i = 0; i < NUM_DATAPOINTS; i++) {
|
---|
742 | if (small_ofs) {
|
---|
743 | p->filter_datapoint[i].d_recv_time += offset;
|
---|
744 | if (p->filter_datapoint[i].d_offset != 0) {
|
---|
745 | p->filter_datapoint[i].d_offset -= offset;
|
---|
746 | //bb_error_msg("p->filter_datapoint[%d].d_offset %f -> %f",
|
---|
747 | // i,
|
---|
748 | // p->filter_datapoint[i].d_offset + offset,
|
---|
749 | // p->filter_datapoint[i].d_offset);
|
---|
750 | }
|
---|
751 | } else {
|
---|
752 | p->filter_datapoint[i].d_recv_time = G.cur_time;
|
---|
753 | p->filter_datapoint[i].d_offset = 0;
|
---|
754 | /*p->filter_datapoint[i].d_dispersion = MAXDISP;*/
|
---|
755 | }
|
---|
756 | }
|
---|
757 | if (small_ofs) {
|
---|
758 | p->lastpkt_recv_time += offset;
|
---|
759 | } else {
|
---|
760 | /*p->reachable_bits = 0;*/
|
---|
761 | p->lastpkt_recv_time = G.cur_time;
|
---|
762 | }
|
---|
763 | filter_datapoints(p); /* recalc p->filter_xxx */
|
---|
764 | VERB6 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
|
---|
765 | }
|
---|
766 |
|
---|
767 | static void
|
---|
768 | resolve_peer_hostname(peer_t *p, int loop_on_fail)
|
---|
769 | {
|
---|
770 | len_and_sockaddr *lsa;
|
---|
771 |
|
---|
772 | again:
|
---|
773 | lsa = host2sockaddr(p->p_hostname, 123);
|
---|
774 | if (!lsa) {
|
---|
775 | /* error message already emitted by host2sockaddr() */
|
---|
776 | if (!loop_on_fail)
|
---|
777 | return;
|
---|
778 | //FIXME: do this to avoid infinite looping on typo in a hostname?
|
---|
779 | //well... in which case, what is a good value for loop_on_fail?
|
---|
780 | //if (--loop_on_fail == 0)
|
---|
781 | // xfunc_die();
|
---|
782 | sleep(5);
|
---|
783 | goto again;
|
---|
784 | }
|
---|
785 | free(p->p_lsa);
|
---|
786 | free(p->p_dotted);
|
---|
787 | p->p_lsa = lsa;
|
---|
788 | p->p_dotted = xmalloc_sockaddr2dotted_noport(&lsa->u.sa);
|
---|
789 | }
|
---|
790 |
|
---|
791 | static void
|
---|
792 | add_peers(const char *s)
|
---|
793 | {
|
---|
794 | llist_t *item;
|
---|
795 | peer_t *p;
|
---|
796 |
|
---|
797 | p = xzalloc(sizeof(*p) + strlen(s));
|
---|
798 | strcpy(p->p_hostname, s);
|
---|
799 | resolve_peer_hostname(p, /*loop_on_fail=*/ 1);
|
---|
800 |
|
---|
801 | /* Names like N.<country2chars>.pool.ntp.org are randomly resolved
|
---|
802 | * to a pool of machines. Sometimes different N's resolve to the same IP.
|
---|
803 | * It is not useful to have two peers with same IP. We skip duplicates.
|
---|
804 | */
|
---|
805 | for (item = G.ntp_peers; item != NULL; item = item->link) {
|
---|
806 | peer_t *pp = (peer_t *) item->data;
|
---|
807 | if (strcmp(p->p_dotted, pp->p_dotted) == 0) {
|
---|
808 | bb_error_msg("duplicate peer %s (%s)", s, p->p_dotted);
|
---|
809 | free(p->p_lsa);
|
---|
810 | free(p->p_dotted);
|
---|
811 | free(p);
|
---|
812 | return;
|
---|
813 | }
|
---|
814 | }
|
---|
815 |
|
---|
816 | p->p_fd = -1;
|
---|
817 | p->p_xmt_msg.m_status = MODE_CLIENT | (NTP_VERSION << 3);
|
---|
818 | p->next_action_time = G.cur_time; /* = set_next(p, 0); */
|
---|
819 | reset_peer_stats(p, STEP_THRESHOLD);
|
---|
820 |
|
---|
821 | llist_add_to(&G.ntp_peers, p);
|
---|
822 | G.peer_cnt++;
|
---|
823 | }
|
---|
824 |
|
---|
825 | static int
|
---|
826 | do_sendto(int fd,
|
---|
827 | const struct sockaddr *from, const struct sockaddr *to, socklen_t addrlen,
|
---|
828 | msg_t *msg, ssize_t len)
|
---|
829 | {
|
---|
830 | ssize_t ret;
|
---|
831 |
|
---|
832 | errno = 0;
|
---|
833 | if (!from) {
|
---|
834 | ret = sendto(fd, msg, len, MSG_DONTWAIT, to, addrlen);
|
---|
835 | } else {
|
---|
836 | ret = send_to_from(fd, msg, len, MSG_DONTWAIT, to, from, addrlen);
|
---|
837 | }
|
---|
838 | if (ret != len) {
|
---|
839 | bb_perror_msg("send failed");
|
---|
840 | return -1;
|
---|
841 | }
|
---|
842 | return 0;
|
---|
843 | }
|
---|
844 |
|
---|
845 | static void
|
---|
846 | send_query_to_peer(peer_t *p)
|
---|
847 | {
|
---|
848 | /* Why do we need to bind()?
|
---|
849 | * See what happens when we don't bind:
|
---|
850 | *
|
---|
851 | * socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
|
---|
852 | * setsockopt(3, SOL_IP, IP_TOS, [16], 4) = 0
|
---|
853 | * gettimeofday({1259071266, 327885}, NULL) = 0
|
---|
854 | * sendto(3, "xxx", 48, MSG_DONTWAIT, {sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr("10.34.32.125")}, 16) = 48
|
---|
855 | * ^^^ we sent it from some source port picked by kernel.
|
---|
856 | * time(NULL) = 1259071266
|
---|
857 | * write(2, "ntpd: entering poll 15 secs\n", 28) = 28
|
---|
858 | * poll([{fd=3, events=POLLIN}], 1, 15000) = 1 ([{fd=3, revents=POLLIN}])
|
---|
859 | * recv(3, "yyy", 68, MSG_DONTWAIT) = 48
|
---|
860 | * ^^^ this recv will receive packets to any local port!
|
---|
861 | *
|
---|
862 | * Uncomment this and use strace to see it in action:
|
---|
863 | */
|
---|
864 | #define PROBE_LOCAL_ADDR /* { len_and_sockaddr lsa; lsa.len = LSA_SIZEOF_SA; getsockname(p->query.fd, &lsa.u.sa, &lsa.len); } */
|
---|
865 |
|
---|
866 | if (p->p_fd == -1) {
|
---|
867 | int fd, family;
|
---|
868 | len_and_sockaddr *local_lsa;
|
---|
869 |
|
---|
870 | family = p->p_lsa->u.sa.sa_family;
|
---|
871 | p->p_fd = fd = xsocket_type(&local_lsa, family, SOCK_DGRAM);
|
---|
872 | /* local_lsa has "null" address and port 0 now.
|
---|
873 | * bind() ensures we have a *particular port* selected by kernel
|
---|
874 | * and remembered in p->p_fd, thus later recv(p->p_fd)
|
---|
875 | * receives only packets sent to this port.
|
---|
876 | */
|
---|
877 | PROBE_LOCAL_ADDR
|
---|
878 | xbind(fd, &local_lsa->u.sa, local_lsa->len);
|
---|
879 | PROBE_LOCAL_ADDR
|
---|
880 | #if ENABLE_FEATURE_IPV6
|
---|
881 | if (family == AF_INET)
|
---|
882 | #endif
|
---|
883 | setsockopt_int(fd, IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY);
|
---|
884 | free(local_lsa);
|
---|
885 | }
|
---|
886 |
|
---|
887 | /* Emit message _before_ attempted send. Think of a very short
|
---|
888 | * roundtrip networks: we need to go back to recv loop ASAP,
|
---|
889 | * to reduce delay. Printing messages after send works against that.
|
---|
890 | */
|
---|
891 | VERB1 bb_error_msg("sending query to %s", p->p_dotted);
|
---|
892 |
|
---|
893 | /*
|
---|
894 | * Send out a random 64-bit number as our transmit time. The NTP
|
---|
895 | * server will copy said number into the originate field on the
|
---|
896 | * response that it sends us. This is totally legal per the SNTP spec.
|
---|
897 | *
|
---|
898 | * The impact of this is two fold: we no longer send out the current
|
---|
899 | * system time for the world to see (which may aid an attacker), and
|
---|
900 | * it gives us a (not very secure) way of knowing that we're not
|
---|
901 | * getting spoofed by an attacker that can't capture our traffic
|
---|
902 | * but can spoof packets from the NTP server we're communicating with.
|
---|
903 | *
|
---|
904 | * Save the real transmit timestamp locally.
|
---|
905 | */
|
---|
906 | p->p_xmt_msg.m_xmttime.int_partl = rand();
|
---|
907 | p->p_xmt_msg.m_xmttime.fractionl = rand();
|
---|
908 | p->p_xmttime = gettime1900d();
|
---|
909 |
|
---|
910 | /* Were doing it only if sendto worked, but
|
---|
911 | * loss of sync detection needs reachable_bits updated
|
---|
912 | * even if sending fails *locally*:
|
---|
913 | * "network is unreachable" because cable was pulled?
|
---|
914 | * We still need to declare "unsync" if this condition persists.
|
---|
915 | */
|
---|
916 | p->reachable_bits <<= 1;
|
---|
917 |
|
---|
918 | if (do_sendto(p->p_fd, /*from:*/ NULL, /*to:*/ &p->p_lsa->u.sa, /*addrlen:*/ p->p_lsa->len,
|
---|
919 | &p->p_xmt_msg, NTP_MSGSIZE_NOAUTH) == -1
|
---|
920 | ) {
|
---|
921 | close(p->p_fd);
|
---|
922 | p->p_fd = -1;
|
---|
923 | /*
|
---|
924 | * We know that we sent nothing.
|
---|
925 | * We can retry *soon* without fearing
|
---|
926 | * that we are flooding the peer.
|
---|
927 | */
|
---|
928 | set_next(p, RETRY_INTERVAL);
|
---|
929 | return;
|
---|
930 | }
|
---|
931 |
|
---|
932 | set_next(p, RESPONSE_INTERVAL);
|
---|
933 | }
|
---|
934 |
|
---|
935 |
|
---|
936 | /* Note that there is no provision to prevent several run_scripts
|
---|
937 | * to be started in quick succession. In fact, it happens rather often
|
---|
938 | * if initial syncronization results in a step.
|
---|
939 | * You will see "step" and then "stratum" script runs, sometimes
|
---|
940 | * as close as only 0.002 seconds apart.
|
---|
941 | * Script should be ready to deal with this.
|
---|
942 | */
|
---|
943 | static void run_script(const char *action, double offset)
|
---|
944 | {
|
---|
945 | char *argv[3];
|
---|
946 | char *env1, *env2, *env3, *env4;
|
---|
947 |
|
---|
948 | G.last_script_run = G.cur_time;
|
---|
949 |
|
---|
950 | if (!G.script_name)
|
---|
951 | return;
|
---|
952 |
|
---|
953 | argv[0] = (char*) G.script_name;
|
---|
954 | argv[1] = (char*) action;
|
---|
955 | argv[2] = NULL;
|
---|
956 |
|
---|
957 | VERB1 bb_error_msg("executing '%s %s'", G.script_name, action);
|
---|
958 |
|
---|
959 | env1 = xasprintf("%s=%u", "stratum", G.stratum);
|
---|
960 | putenv(env1);
|
---|
961 | env2 = xasprintf("%s=%ld", "freq_drift_ppm", G.kernel_freq_drift);
|
---|
962 | putenv(env2);
|
---|
963 | env3 = xasprintf("%s=%u", "poll_interval", 1 << G.poll_exp);
|
---|
964 | putenv(env3);
|
---|
965 | env4 = xasprintf("%s=%f", "offset", offset);
|
---|
966 | putenv(env4);
|
---|
967 | /* Other items of potential interest: selected peer,
|
---|
968 | * rootdelay, reftime, rootdisp, refid, ntp_status,
|
---|
969 | * last_update_offset, last_update_recv_time, discipline_jitter,
|
---|
970 | * how many peers have reachable_bits = 0?
|
---|
971 | */
|
---|
972 |
|
---|
973 | /* Don't want to wait: it may run hwclock --systohc, and that
|
---|
974 | * may take some time (seconds): */
|
---|
975 | /*spawn_and_wait(argv);*/
|
---|
976 | spawn(argv);
|
---|
977 |
|
---|
978 | unsetenv("stratum");
|
---|
979 | unsetenv("freq_drift_ppm");
|
---|
980 | unsetenv("poll_interval");
|
---|
981 | unsetenv("offset");
|
---|
982 | free(env1);
|
---|
983 | free(env2);
|
---|
984 | free(env3);
|
---|
985 | free(env4);
|
---|
986 | }
|
---|
987 |
|
---|
988 | static NOINLINE void
|
---|
989 | step_time(double offset)
|
---|
990 | {
|
---|
991 | llist_t *item;
|
---|
992 | double dtime;
|
---|
993 | struct timeval tvc, tvn;
|
---|
994 | char buf[sizeof("yyyy-mm-dd hh:mm:ss") + /*paranoia:*/ 4];
|
---|
995 | time_t tval;
|
---|
996 |
|
---|
997 | gettimeofday(&tvc, NULL); /* never fails */
|
---|
998 | dtime = tvc.tv_sec + (1.0e-6 * tvc.tv_usec) + offset;
|
---|
999 | d_to_tv(dtime, &tvn);
|
---|
1000 | if (settimeofday(&tvn, NULL) == -1)
|
---|
1001 | bb_perror_msg_and_die("settimeofday");
|
---|
1002 |
|
---|
1003 | VERB2 {
|
---|
1004 | tval = tvc.tv_sec;
|
---|
1005 | strftime_YYYYMMDDHHMMSS(buf, sizeof(buf), &tval);
|
---|
1006 | bb_error_msg("current time is %s.%06u", buf, (unsigned)tvc.tv_usec);
|
---|
1007 | }
|
---|
1008 | tval = tvn.tv_sec;
|
---|
1009 | strftime_YYYYMMDDHHMMSS(buf, sizeof(buf), &tval);
|
---|
1010 | bb_error_msg("setting time to %s.%06u (offset %+fs)", buf, (unsigned)tvn.tv_usec, offset);
|
---|
1011 |
|
---|
1012 | /* Correct various fields which contain time-relative values: */
|
---|
1013 |
|
---|
1014 | /* Globals: */
|
---|
1015 | G.cur_time += offset;
|
---|
1016 | G.last_update_recv_time += offset;
|
---|
1017 | G.last_script_run += offset;
|
---|
1018 |
|
---|
1019 | /* p->lastpkt_recv_time, p->next_action_time and such: */
|
---|
1020 | for (item = G.ntp_peers; item != NULL; item = item->link) {
|
---|
1021 | peer_t *pp = (peer_t *) item->data;
|
---|
1022 | reset_peer_stats(pp, offset);
|
---|
1023 | //bb_error_msg("offset:%+f pp->next_action_time:%f -> %f",
|
---|
1024 | // offset, pp->next_action_time, pp->next_action_time + offset);
|
---|
1025 | pp->next_action_time += offset;
|
---|
1026 | if (pp->p_fd >= 0) {
|
---|
1027 | /* We wait for reply from this peer too.
|
---|
1028 | * But due to step we are doing, reply's data is no longer
|
---|
1029 | * useful (in fact, it'll be bogus). Stop waiting for it.
|
---|
1030 | */
|
---|
1031 | close(pp->p_fd);
|
---|
1032 | pp->p_fd = -1;
|
---|
1033 | set_next(pp, RETRY_INTERVAL);
|
---|
1034 | }
|
---|
1035 | }
|
---|
1036 | }
|
---|
1037 |
|
---|
1038 | static void clamp_pollexp_and_set_MAXSTRAT(void)
|
---|
1039 | {
|
---|
1040 | if (G.poll_exp < MINPOLL)
|
---|
1041 | G.poll_exp = MINPOLL;
|
---|
1042 | if (G.poll_exp > BIGPOLL)
|
---|
1043 | G.poll_exp = BIGPOLL;
|
---|
1044 | G.polladj_count = 0;
|
---|
1045 | G.stratum = MAXSTRAT;
|
---|
1046 | }
|
---|
1047 |
|
---|
1048 |
|
---|
1049 | /*
|
---|
1050 | * Selection and clustering, and their helpers
|
---|
1051 | */
|
---|
1052 | typedef struct {
|
---|
1053 | peer_t *p;
|
---|
1054 | int type;
|
---|
1055 | double edge;
|
---|
1056 | double opt_rd; /* optimization */
|
---|
1057 | } point_t;
|
---|
1058 | static int
|
---|
1059 | compare_point_edge(const void *aa, const void *bb)
|
---|
1060 | {
|
---|
1061 | const point_t *a = aa;
|
---|
1062 | const point_t *b = bb;
|
---|
1063 | if (a->edge < b->edge) {
|
---|
1064 | return -1;
|
---|
1065 | }
|
---|
1066 | return (a->edge > b->edge);
|
---|
1067 | }
|
---|
1068 | typedef struct {
|
---|
1069 | peer_t *p;
|
---|
1070 | double metric;
|
---|
1071 | } survivor_t;
|
---|
1072 | static int
|
---|
1073 | compare_survivor_metric(const void *aa, const void *bb)
|
---|
1074 | {
|
---|
1075 | const survivor_t *a = aa;
|
---|
1076 | const survivor_t *b = bb;
|
---|
1077 | if (a->metric < b->metric) {
|
---|
1078 | return -1;
|
---|
1079 | }
|
---|
1080 | return (a->metric > b->metric);
|
---|
1081 | }
|
---|
1082 | static int
|
---|
1083 | fit(peer_t *p, double rd)
|
---|
1084 | {
|
---|
1085 | if ((p->reachable_bits & (p->reachable_bits-1)) == 0) {
|
---|
1086 | /* One or zero bits in reachable_bits */
|
---|
1087 | VERB4 bb_error_msg("peer %s unfit for selection: unreachable", p->p_dotted);
|
---|
1088 | return 0;
|
---|
1089 | }
|
---|
1090 | #if 0 /* we filter out such packets earlier */
|
---|
1091 | if ((p->lastpkt_status & LI_ALARM) == LI_ALARM
|
---|
1092 | || p->lastpkt_stratum >= MAXSTRAT
|
---|
1093 | ) {
|
---|
1094 | VERB4 bb_error_msg("peer %s unfit for selection: bad status/stratum", p->p_dotted);
|
---|
1095 | return 0;
|
---|
1096 | }
|
---|
1097 | #endif
|
---|
1098 | /* rd is root_distance(p) */
|
---|
1099 | if (rd > MAXDIST + FREQ_TOLERANCE * (1 << G.poll_exp)) {
|
---|
1100 | VERB4 bb_error_msg("peer %s unfit for selection: root distance too high", p->p_dotted);
|
---|
1101 | return 0;
|
---|
1102 | }
|
---|
1103 | //TODO
|
---|
1104 | // /* Do we have a loop? */
|
---|
1105 | // if (p->refid == p->dstaddr || p->refid == s.refid)
|
---|
1106 | // return 0;
|
---|
1107 | return 1;
|
---|
1108 | }
|
---|
1109 | static peer_t*
|
---|
1110 | select_and_cluster(void)
|
---|
1111 | {
|
---|
1112 | peer_t *p;
|
---|
1113 | llist_t *item;
|
---|
1114 | int i, j;
|
---|
1115 | int size = 3 * G.peer_cnt;
|
---|
1116 | /* for selection algorithm */
|
---|
1117 | point_t point[size];
|
---|
1118 | unsigned num_points, num_candidates;
|
---|
1119 | double low, high;
|
---|
1120 | unsigned num_falsetickers;
|
---|
1121 | /* for cluster algorithm */
|
---|
1122 | survivor_t survivor[size];
|
---|
1123 | unsigned num_survivors;
|
---|
1124 |
|
---|
1125 | /* Selection */
|
---|
1126 |
|
---|
1127 | num_points = 0;
|
---|
1128 | item = G.ntp_peers;
|
---|
1129 | while (item != NULL) {
|
---|
1130 | double rd, offset;
|
---|
1131 |
|
---|
1132 | p = (peer_t *) item->data;
|
---|
1133 | rd = root_distance(p);
|
---|
1134 | offset = p->filter_offset;
|
---|
1135 | if (!fit(p, rd)) {
|
---|
1136 | item = item->link;
|
---|
1137 | continue;
|
---|
1138 | }
|
---|
1139 |
|
---|
1140 | VERB5 bb_error_msg("interval: [%f %f %f] %s",
|
---|
1141 | offset - rd,
|
---|
1142 | offset,
|
---|
1143 | offset + rd,
|
---|
1144 | p->p_dotted
|
---|
1145 | );
|
---|
1146 | point[num_points].p = p;
|
---|
1147 | point[num_points].type = -1;
|
---|
1148 | point[num_points].edge = offset - rd;
|
---|
1149 | point[num_points].opt_rd = rd;
|
---|
1150 | num_points++;
|
---|
1151 | point[num_points].p = p;
|
---|
1152 | point[num_points].type = 0;
|
---|
1153 | point[num_points].edge = offset;
|
---|
1154 | point[num_points].opt_rd = rd;
|
---|
1155 | num_points++;
|
---|
1156 | point[num_points].p = p;
|
---|
1157 | point[num_points].type = 1;
|
---|
1158 | point[num_points].edge = offset + rd;
|
---|
1159 | point[num_points].opt_rd = rd;
|
---|
1160 | num_points++;
|
---|
1161 | item = item->link;
|
---|
1162 | }
|
---|
1163 | num_candidates = num_points / 3;
|
---|
1164 | if (num_candidates == 0) {
|
---|
1165 | VERB3 bb_error_msg("no valid datapoints%s", ", no peer selected");
|
---|
1166 | return NULL;
|
---|
1167 | }
|
---|
1168 | //TODO: sorting does not seem to be done in reference code
|
---|
1169 | qsort(point, num_points, sizeof(point[0]), compare_point_edge);
|
---|
1170 |
|
---|
1171 | /* Start with the assumption that there are no falsetickers.
|
---|
1172 | * Attempt to find a nonempty intersection interval containing
|
---|
1173 | * the midpoints of all truechimers.
|
---|
1174 | * If a nonempty interval cannot be found, increase the number
|
---|
1175 | * of assumed falsetickers by one and try again.
|
---|
1176 | * If a nonempty interval is found and the number of falsetickers
|
---|
1177 | * is less than the number of truechimers, a majority has been found
|
---|
1178 | * and the midpoint of each truechimer represents
|
---|
1179 | * the candidates available to the cluster algorithm.
|
---|
1180 | */
|
---|
1181 | num_falsetickers = 0;
|
---|
1182 | while (1) {
|
---|
1183 | int c;
|
---|
1184 | unsigned num_midpoints = 0;
|
---|
1185 |
|
---|
1186 | low = 1 << 9;
|
---|
1187 | high = - (1 << 9);
|
---|
1188 | c = 0;
|
---|
1189 | for (i = 0; i < num_points; i++) {
|
---|
1190 | /* We want to do:
|
---|
1191 | * if (point[i].type == -1) c++;
|
---|
1192 | * if (point[i].type == 1) c--;
|
---|
1193 | * and it's simpler to do it this way:
|
---|
1194 | */
|
---|
1195 | c -= point[i].type;
|
---|
1196 | if (c >= num_candidates - num_falsetickers) {
|
---|
1197 | /* If it was c++ and it got big enough... */
|
---|
1198 | low = point[i].edge;
|
---|
1199 | break;
|
---|
1200 | }
|
---|
1201 | if (point[i].type == 0)
|
---|
1202 | num_midpoints++;
|
---|
1203 | }
|
---|
1204 | c = 0;
|
---|
1205 | for (i = num_points-1; i >= 0; i--) {
|
---|
1206 | c += point[i].type;
|
---|
1207 | if (c >= num_candidates - num_falsetickers) {
|
---|
1208 | high = point[i].edge;
|
---|
1209 | break;
|
---|
1210 | }
|
---|
1211 | if (point[i].type == 0)
|
---|
1212 | num_midpoints++;
|
---|
1213 | }
|
---|
1214 | /* If the number of midpoints is greater than the number
|
---|
1215 | * of allowed falsetickers, the intersection contains at
|
---|
1216 | * least one truechimer with no midpoint - bad.
|
---|
1217 | * Also, interval should be nonempty.
|
---|
1218 | */
|
---|
1219 | if (num_midpoints <= num_falsetickers && low < high)
|
---|
1220 | break;
|
---|
1221 | num_falsetickers++;
|
---|
1222 | if (num_falsetickers * 2 >= num_candidates) {
|
---|
1223 | VERB3 bb_error_msg("falsetickers:%d, candidates:%d%s",
|
---|
1224 | num_falsetickers, num_candidates,
|
---|
1225 | ", no peer selected");
|
---|
1226 | return NULL;
|
---|
1227 | }
|
---|
1228 | }
|
---|
1229 | VERB4 bb_error_msg("selected interval: [%f, %f]; candidates:%d falsetickers:%d",
|
---|
1230 | low, high, num_candidates, num_falsetickers);
|
---|
1231 |
|
---|
1232 | /* Clustering */
|
---|
1233 |
|
---|
1234 | /* Construct a list of survivors (p, metric)
|
---|
1235 | * from the chime list, where metric is dominated
|
---|
1236 | * first by stratum and then by root distance.
|
---|
1237 | * All other things being equal, this is the order of preference.
|
---|
1238 | */
|
---|
1239 | num_survivors = 0;
|
---|
1240 | for (i = 0; i < num_points; i++) {
|
---|
1241 | if (point[i].edge < low || point[i].edge > high)
|
---|
1242 | continue;
|
---|
1243 | p = point[i].p;
|
---|
1244 | survivor[num_survivors].p = p;
|
---|
1245 | /* x.opt_rd == root_distance(p); */
|
---|
1246 | survivor[num_survivors].metric = MAXDIST * p->lastpkt_stratum + point[i].opt_rd;
|
---|
1247 | VERB5 bb_error_msg("survivor[%d] metric:%f peer:%s",
|
---|
1248 | num_survivors, survivor[num_survivors].metric, p->p_dotted);
|
---|
1249 | num_survivors++;
|
---|
1250 | }
|
---|
1251 | /* There must be at least MIN_SELECTED survivors to satisfy the
|
---|
1252 | * correctness assertions. Ordinarily, the Byzantine criteria
|
---|
1253 | * require four survivors, but for the demonstration here, one
|
---|
1254 | * is acceptable.
|
---|
1255 | */
|
---|
1256 | if (num_survivors < MIN_SELECTED) {
|
---|
1257 | VERB3 bb_error_msg("survivors:%d%s",
|
---|
1258 | num_survivors,
|
---|
1259 | ", no peer selected");
|
---|
1260 | return NULL;
|
---|
1261 | }
|
---|
1262 |
|
---|
1263 | //looks like this is ONLY used by the fact that later we pick survivor[0].
|
---|
1264 | //we can avoid sorting then, just find the minimum once!
|
---|
1265 | qsort(survivor, num_survivors, sizeof(survivor[0]), compare_survivor_metric);
|
---|
1266 |
|
---|
1267 | /* For each association p in turn, calculate the selection
|
---|
1268 | * jitter p->sjitter as the square root of the sum of squares
|
---|
1269 | * (p->offset - q->offset) over all q associations. The idea is
|
---|
1270 | * to repeatedly discard the survivor with maximum selection
|
---|
1271 | * jitter until a termination condition is met.
|
---|
1272 | */
|
---|
1273 | while (1) {
|
---|
1274 | unsigned max_idx = max_idx;
|
---|
1275 | double max_selection_jitter = max_selection_jitter;
|
---|
1276 | double min_jitter = min_jitter;
|
---|
1277 |
|
---|
1278 | if (num_survivors <= MIN_CLUSTERED) {
|
---|
1279 | VERB4 bb_error_msg("num_survivors %d <= %d, not discarding more",
|
---|
1280 | num_survivors, MIN_CLUSTERED);
|
---|
1281 | break;
|
---|
1282 | }
|
---|
1283 |
|
---|
1284 | /* To make sure a few survivors are left
|
---|
1285 | * for the clustering algorithm to chew on,
|
---|
1286 | * we stop if the number of survivors
|
---|
1287 | * is less than or equal to MIN_CLUSTERED (3).
|
---|
1288 | */
|
---|
1289 | for (i = 0; i < num_survivors; i++) {
|
---|
1290 | double selection_jitter_sq;
|
---|
1291 |
|
---|
1292 | p = survivor[i].p;
|
---|
1293 | if (i == 0 || p->filter_jitter < min_jitter)
|
---|
1294 | min_jitter = p->filter_jitter;
|
---|
1295 |
|
---|
1296 | selection_jitter_sq = 0;
|
---|
1297 | for (j = 0; j < num_survivors; j++) {
|
---|
1298 | peer_t *q = survivor[j].p;
|
---|
1299 | selection_jitter_sq += SQUARE(p->filter_offset - q->filter_offset);
|
---|
1300 | }
|
---|
1301 | if (i == 0 || selection_jitter_sq > max_selection_jitter) {
|
---|
1302 | max_selection_jitter = selection_jitter_sq;
|
---|
1303 | max_idx = i;
|
---|
1304 | }
|
---|
1305 | VERB6 bb_error_msg("survivor %d selection_jitter^2:%f",
|
---|
1306 | i, selection_jitter_sq);
|
---|
1307 | }
|
---|
1308 | max_selection_jitter = SQRT(max_selection_jitter / num_survivors);
|
---|
1309 | VERB5 bb_error_msg("max_selection_jitter (at %d):%f min_jitter:%f",
|
---|
1310 | max_idx, max_selection_jitter, min_jitter);
|
---|
1311 |
|
---|
1312 | /* If the maximum selection jitter is less than the
|
---|
1313 | * minimum peer jitter, then tossing out more survivors
|
---|
1314 | * will not lower the minimum peer jitter, so we might
|
---|
1315 | * as well stop.
|
---|
1316 | */
|
---|
1317 | if (max_selection_jitter < min_jitter) {
|
---|
1318 | VERB4 bb_error_msg("max_selection_jitter:%f < min_jitter:%f, num_survivors:%d, not discarding more",
|
---|
1319 | max_selection_jitter, min_jitter, num_survivors);
|
---|
1320 | break;
|
---|
1321 | }
|
---|
1322 |
|
---|
1323 | /* Delete survivor[max_idx] from the list
|
---|
1324 | * and go around again.
|
---|
1325 | */
|
---|
1326 | VERB6 bb_error_msg("dropping survivor %d", max_idx);
|
---|
1327 | num_survivors--;
|
---|
1328 | while (max_idx < num_survivors) {
|
---|
1329 | survivor[max_idx] = survivor[max_idx + 1];
|
---|
1330 | max_idx++;
|
---|
1331 | }
|
---|
1332 | }
|
---|
1333 |
|
---|
1334 | if (0) {
|
---|
1335 | /* Combine the offsets of the clustering algorithm survivors
|
---|
1336 | * using a weighted average with weight determined by the root
|
---|
1337 | * distance. Compute the selection jitter as the weighted RMS
|
---|
1338 | * difference between the first survivor and the remaining
|
---|
1339 | * survivors. In some cases the inherent clock jitter can be
|
---|
1340 | * reduced by not using this algorithm, especially when frequent
|
---|
1341 | * clockhopping is involved. bbox: thus we don't do it.
|
---|
1342 | */
|
---|
1343 | double x, y, z, w;
|
---|
1344 | y = z = w = 0;
|
---|
1345 | for (i = 0; i < num_survivors; i++) {
|
---|
1346 | p = survivor[i].p;
|
---|
1347 | x = root_distance(p);
|
---|
1348 | y += 1 / x;
|
---|
1349 | z += p->filter_offset / x;
|
---|
1350 | w += SQUARE(p->filter_offset - survivor[0].p->filter_offset) / x;
|
---|
1351 | }
|
---|
1352 | //G.cluster_offset = z / y;
|
---|
1353 | //G.cluster_jitter = SQRT(w / y);
|
---|
1354 | }
|
---|
1355 |
|
---|
1356 | /* Pick the best clock. If the old system peer is on the list
|
---|
1357 | * and at the same stratum as the first survivor on the list,
|
---|
1358 | * then don't do a clock hop. Otherwise, select the first
|
---|
1359 | * survivor on the list as the new system peer.
|
---|
1360 | */
|
---|
1361 | p = survivor[0].p;
|
---|
1362 | if (G.last_update_peer
|
---|
1363 | && G.last_update_peer->lastpkt_stratum <= p->lastpkt_stratum
|
---|
1364 | ) {
|
---|
1365 | /* Starting from 1 is ok here */
|
---|
1366 | for (i = 1; i < num_survivors; i++) {
|
---|
1367 | if (G.last_update_peer == survivor[i].p) {
|
---|
1368 | VERB5 bb_error_msg("keeping old synced peer");
|
---|
1369 | p = G.last_update_peer;
|
---|
1370 | goto keep_old;
|
---|
1371 | }
|
---|
1372 | }
|
---|
1373 | }
|
---|
1374 | G.last_update_peer = p;
|
---|
1375 | keep_old:
|
---|
1376 | VERB4 bb_error_msg("selected peer %s filter_offset:%+f age:%f",
|
---|
1377 | p->p_dotted,
|
---|
1378 | p->filter_offset,
|
---|
1379 | G.cur_time - p->lastpkt_recv_time
|
---|
1380 | );
|
---|
1381 | return p;
|
---|
1382 | }
|
---|
1383 |
|
---|
1384 |
|
---|
1385 | /*
|
---|
1386 | * Local clock discipline and its helpers
|
---|
1387 | */
|
---|
1388 | static void
|
---|
1389 | set_new_values(int disc_state, double offset, double recv_time)
|
---|
1390 | {
|
---|
1391 | /* Enter new state and set state variables. Note we use the time
|
---|
1392 | * of the last clock filter sample, which must be earlier than
|
---|
1393 | * the current time.
|
---|
1394 | */
|
---|
1395 | VERB4 bb_error_msg("disc_state=%d last update offset=%f recv_time=%f",
|
---|
1396 | disc_state, offset, recv_time);
|
---|
1397 | G.discipline_state = disc_state;
|
---|
1398 | G.last_update_offset = offset;
|
---|
1399 | G.last_update_recv_time = recv_time;
|
---|
1400 | }
|
---|
1401 | /* Return: -1: decrease poll interval, 0: leave as is, 1: increase */
|
---|
1402 | static NOINLINE int
|
---|
1403 | update_local_clock(peer_t *p)
|
---|
1404 | {
|
---|
1405 | int rc;
|
---|
1406 | struct timex tmx;
|
---|
1407 | /* Note: can use G.cluster_offset instead: */
|
---|
1408 | double offset = p->filter_offset;
|
---|
1409 | double recv_time = p->lastpkt_recv_time;
|
---|
1410 | double abs_offset;
|
---|
1411 | #if !USING_KERNEL_PLL_LOOP
|
---|
1412 | double freq_drift;
|
---|
1413 | #endif
|
---|
1414 | #if !USING_KERNEL_PLL_LOOP || USING_INITIAL_FREQ_ESTIMATION
|
---|
1415 | double since_last_update;
|
---|
1416 | #endif
|
---|
1417 | double etemp, dtemp;
|
---|
1418 |
|
---|
1419 | abs_offset = fabs(offset);
|
---|
1420 |
|
---|
1421 | #if 0
|
---|
1422 | /* If needed, -S script can do it by looking at $offset
|
---|
1423 | * env var and killing parent */
|
---|
1424 | /* If the offset is too large, give up and go home */
|
---|
1425 | if (abs_offset > PANIC_THRESHOLD) {
|
---|
1426 | bb_error_msg_and_die("offset %f far too big, exiting", offset);
|
---|
1427 | }
|
---|
1428 | #endif
|
---|
1429 |
|
---|
1430 | /* If this is an old update, for instance as the result
|
---|
1431 | * of a system peer change, avoid it. We never use
|
---|
1432 | * an old sample or the same sample twice.
|
---|
1433 | */
|
---|
1434 | if (recv_time <= G.last_update_recv_time) {
|
---|
1435 | VERB3 bb_error_msg("update from %s: same or older datapoint, not using it",
|
---|
1436 | p->p_dotted);
|
---|
1437 | return 0; /* "leave poll interval as is" */
|
---|
1438 | }
|
---|
1439 |
|
---|
1440 | /* Clock state machine transition function. This is where the
|
---|
1441 | * action is and defines how the system reacts to large time
|
---|
1442 | * and frequency errors.
|
---|
1443 | */
|
---|
1444 | #if !USING_KERNEL_PLL_LOOP || USING_INITIAL_FREQ_ESTIMATION
|
---|
1445 | since_last_update = recv_time - G.reftime;
|
---|
1446 | #endif
|
---|
1447 | #if !USING_KERNEL_PLL_LOOP
|
---|
1448 | freq_drift = 0;
|
---|
1449 | #endif
|
---|
1450 | #if USING_INITIAL_FREQ_ESTIMATION
|
---|
1451 | if (G.discipline_state == STATE_FREQ) {
|
---|
1452 | /* Ignore updates until the stepout threshold */
|
---|
1453 | if (since_last_update < WATCH_THRESHOLD) {
|
---|
1454 | VERB4 bb_error_msg("measuring drift, datapoint ignored, %f sec remains",
|
---|
1455 | WATCH_THRESHOLD - since_last_update);
|
---|
1456 | return 0; /* "leave poll interval as is" */
|
---|
1457 | }
|
---|
1458 | # if !USING_KERNEL_PLL_LOOP
|
---|
1459 | freq_drift = (offset - G.last_update_offset) / since_last_update;
|
---|
1460 | # endif
|
---|
1461 | }
|
---|
1462 | #endif
|
---|
1463 |
|
---|
1464 | /* There are two main regimes: when the
|
---|
1465 | * offset exceeds the step threshold and when it does not.
|
---|
1466 | */
|
---|
1467 | if (abs_offset > STEP_THRESHOLD) {
|
---|
1468 | #if 0
|
---|
1469 | double remains;
|
---|
1470 |
|
---|
1471 | // This "spike state" seems to be useless, peer selection already drops
|
---|
1472 | // occassional "bad" datapoints. If we are here, there were _many_
|
---|
1473 | // large offsets. When a few first large offsets are seen,
|
---|
1474 | // we end up in "no valid datapoints, no peer selected" state.
|
---|
1475 | // Only when enough of them are seen (which means it's not a fluke),
|
---|
1476 | // we end up here. Looks like _our_ clock is off.
|
---|
1477 | switch (G.discipline_state) {
|
---|
1478 | case STATE_SYNC:
|
---|
1479 | /* The first outlyer: ignore it, switch to SPIK state */
|
---|
1480 | VERB3 bb_error_msg("update from %s: offset:%+f, spike%s",
|
---|
1481 | p->p_dotted, offset,
|
---|
1482 | "");
|
---|
1483 | G.discipline_state = STATE_SPIK;
|
---|
1484 | return -1; /* "decrease poll interval" */
|
---|
1485 |
|
---|
1486 | case STATE_SPIK:
|
---|
1487 | /* Ignore succeeding outlyers until either an inlyer
|
---|
1488 | * is found or the stepout threshold is exceeded.
|
---|
1489 | */
|
---|
1490 | remains = WATCH_THRESHOLD - since_last_update;
|
---|
1491 | if (remains > 0) {
|
---|
1492 | VERB3 bb_error_msg("update from %s: offset:%+f, spike%s",
|
---|
1493 | p->p_dotted, offset,
|
---|
1494 | ", datapoint ignored");
|
---|
1495 | return -1; /* "decrease poll interval" */
|
---|
1496 | }
|
---|
1497 | /* fall through: we need to step */
|
---|
1498 | } /* switch */
|
---|
1499 | #endif
|
---|
1500 |
|
---|
1501 | /* Step the time and clamp down the poll interval.
|
---|
1502 | *
|
---|
1503 | * In NSET state an initial frequency correction is
|
---|
1504 | * not available, usually because the frequency file has
|
---|
1505 | * not yet been written. Since the time is outside the
|
---|
1506 | * capture range, the clock is stepped. The frequency
|
---|
1507 | * will be set directly following the stepout interval.
|
---|
1508 | *
|
---|
1509 | * In FSET state the initial frequency has been set
|
---|
1510 | * from the frequency file. Since the time is outside
|
---|
1511 | * the capture range, the clock is stepped immediately,
|
---|
1512 | * rather than after the stepout interval. Guys get
|
---|
1513 | * nervous if it takes 17 minutes to set the clock for
|
---|
1514 | * the first time.
|
---|
1515 | *
|
---|
1516 | * In SPIK state the stepout threshold has expired and
|
---|
1517 | * the phase is still above the step threshold. Note
|
---|
1518 | * that a single spike greater than the step threshold
|
---|
1519 | * is always suppressed, even at the longer poll
|
---|
1520 | * intervals.
|
---|
1521 | */
|
---|
1522 | VERB4 bb_error_msg("stepping time by %+f; poll_exp=MINPOLL", offset);
|
---|
1523 | step_time(offset);
|
---|
1524 | if (option_mask32 & OPT_q) {
|
---|
1525 | /* We were only asked to set time once. Done. */
|
---|
1526 | exit(0);
|
---|
1527 | }
|
---|
1528 |
|
---|
1529 | clamp_pollexp_and_set_MAXSTRAT();
|
---|
1530 |
|
---|
1531 | run_script("step", offset);
|
---|
1532 |
|
---|
1533 | recv_time += offset;
|
---|
1534 |
|
---|
1535 | #if USING_INITIAL_FREQ_ESTIMATION
|
---|
1536 | if (G.discipline_state == STATE_NSET) {
|
---|
1537 | set_new_values(STATE_FREQ, /*offset:*/ 0, recv_time);
|
---|
1538 | return 1; /* "ok to increase poll interval" */
|
---|
1539 | }
|
---|
1540 | #endif
|
---|
1541 | abs_offset = offset = 0;
|
---|
1542 | set_new_values(STATE_SYNC, offset, recv_time);
|
---|
1543 | } else { /* abs_offset <= STEP_THRESHOLD */
|
---|
1544 |
|
---|
1545 | /* The ratio is calculated before jitter is updated to make
|
---|
1546 | * poll adjust code more sensitive to large offsets.
|
---|
1547 | */
|
---|
1548 | G.offset_to_jitter_ratio = abs_offset / G.discipline_jitter;
|
---|
1549 |
|
---|
1550 | /* Compute the clock jitter as the RMS of exponentially
|
---|
1551 | * weighted offset differences. Used by the poll adjust code.
|
---|
1552 | */
|
---|
1553 | etemp = SQUARE(G.discipline_jitter);
|
---|
1554 | dtemp = SQUARE(offset - G.last_update_offset);
|
---|
1555 | G.discipline_jitter = SQRT(etemp + (dtemp - etemp) / AVG);
|
---|
1556 | if (G.discipline_jitter < G_precision_sec)
|
---|
1557 | G.discipline_jitter = G_precision_sec;
|
---|
1558 |
|
---|
1559 | switch (G.discipline_state) {
|
---|
1560 | case STATE_NSET:
|
---|
1561 | if (option_mask32 & OPT_q) {
|
---|
1562 | /* We were only asked to set time once.
|
---|
1563 | * The clock is precise enough, no need to step.
|
---|
1564 | */
|
---|
1565 | exit(0);
|
---|
1566 | }
|
---|
1567 | #if USING_INITIAL_FREQ_ESTIMATION
|
---|
1568 | /* This is the first update received and the frequency
|
---|
1569 | * has not been initialized. The first thing to do
|
---|
1570 | * is directly measure the oscillator frequency.
|
---|
1571 | */
|
---|
1572 | set_new_values(STATE_FREQ, offset, recv_time);
|
---|
1573 | #else
|
---|
1574 | set_new_values(STATE_SYNC, offset, recv_time);
|
---|
1575 | #endif
|
---|
1576 | VERB4 bb_error_msg("transitioning to FREQ, datapoint ignored");
|
---|
1577 | return 0; /* "leave poll interval as is" */
|
---|
1578 |
|
---|
1579 | #if 0 /* this is dead code for now */
|
---|
1580 | case STATE_FSET:
|
---|
1581 | /* This is the first update and the frequency
|
---|
1582 | * has been initialized. Adjust the phase, but
|
---|
1583 | * don't adjust the frequency until the next update.
|
---|
1584 | */
|
---|
1585 | set_new_values(STATE_SYNC, offset, recv_time);
|
---|
1586 | /* freq_drift remains 0 */
|
---|
1587 | break;
|
---|
1588 | #endif
|
---|
1589 |
|
---|
1590 | #if USING_INITIAL_FREQ_ESTIMATION
|
---|
1591 | case STATE_FREQ:
|
---|
1592 | /* since_last_update >= WATCH_THRESHOLD, we waited enough.
|
---|
1593 | * Correct the phase and frequency and switch to SYNC state.
|
---|
1594 | * freq_drift was already estimated (see code above)
|
---|
1595 | */
|
---|
1596 | set_new_values(STATE_SYNC, offset, recv_time);
|
---|
1597 | break;
|
---|
1598 | #endif
|
---|
1599 |
|
---|
1600 | default:
|
---|
1601 | #if !USING_KERNEL_PLL_LOOP
|
---|
1602 | /* Compute freq_drift due to PLL and FLL contributions.
|
---|
1603 | *
|
---|
1604 | * The FLL and PLL frequency gain constants
|
---|
1605 | * depend on the poll interval and Allan
|
---|
1606 | * intercept. The FLL is not used below one-half
|
---|
1607 | * the Allan intercept. Above that the loop gain
|
---|
1608 | * increases in steps to 1 / AVG.
|
---|
1609 | */
|
---|
1610 | if ((1 << G.poll_exp) > ALLAN / 2) {
|
---|
1611 | etemp = FLL - G.poll_exp;
|
---|
1612 | if (etemp < AVG)
|
---|
1613 | etemp = AVG;
|
---|
1614 | freq_drift += (offset - G.last_update_offset) / (MAXD(since_last_update, ALLAN) * etemp);
|
---|
1615 | }
|
---|
1616 | /* For the PLL the integration interval
|
---|
1617 | * (numerator) is the minimum of the update
|
---|
1618 | * interval and poll interval. This allows
|
---|
1619 | * oversampling, but not undersampling.
|
---|
1620 | */
|
---|
1621 | etemp = MIND(since_last_update, (1 << G.poll_exp));
|
---|
1622 | dtemp = (4 * PLL) << G.poll_exp;
|
---|
1623 | freq_drift += offset * etemp / SQUARE(dtemp);
|
---|
1624 | #endif
|
---|
1625 | set_new_values(STATE_SYNC, offset, recv_time);
|
---|
1626 | break;
|
---|
1627 | }
|
---|
1628 | if (G.stratum != p->lastpkt_stratum + 1) {
|
---|
1629 | G.stratum = p->lastpkt_stratum + 1;
|
---|
1630 | run_script("stratum", offset);
|
---|
1631 | }
|
---|
1632 | }
|
---|
1633 |
|
---|
1634 | G.reftime = G.cur_time;
|
---|
1635 | G.ntp_status = p->lastpkt_status;
|
---|
1636 | G.refid = p->lastpkt_refid;
|
---|
1637 | G.rootdelay = p->lastpkt_rootdelay + p->lastpkt_delay;
|
---|
1638 | dtemp = p->filter_jitter; // SQRT(SQUARE(p->filter_jitter) + SQUARE(G.cluster_jitter));
|
---|
1639 | dtemp += MAXD(p->filter_dispersion + FREQ_TOLERANCE * (G.cur_time - p->lastpkt_recv_time) + abs_offset, MINDISP);
|
---|
1640 | G.rootdisp = p->lastpkt_rootdisp + dtemp;
|
---|
1641 | VERB4 bb_error_msg("updating leap/refid/reftime/rootdisp from peer %s", p->p_dotted);
|
---|
1642 |
|
---|
1643 | /* We are in STATE_SYNC now, but did not do adjtimex yet.
|
---|
1644 | * (Any other state does not reach this, they all return earlier)
|
---|
1645 | * By this time, freq_drift and offset are set
|
---|
1646 | * to values suitable for adjtimex.
|
---|
1647 | */
|
---|
1648 | #if !USING_KERNEL_PLL_LOOP
|
---|
1649 | /* Calculate the new frequency drift and frequency stability (wander).
|
---|
1650 | * Compute the clock wander as the RMS of exponentially weighted
|
---|
1651 | * frequency differences. This is not used directly, but can,
|
---|
1652 | * along with the jitter, be a highly useful monitoring and
|
---|
1653 | * debugging tool.
|
---|
1654 | */
|
---|
1655 | dtemp = G.discipline_freq_drift + freq_drift;
|
---|
1656 | G.discipline_freq_drift = MAXD(MIND(MAXDRIFT, dtemp), -MAXDRIFT);
|
---|
1657 | etemp = SQUARE(G.discipline_wander);
|
---|
1658 | dtemp = SQUARE(dtemp);
|
---|
1659 | G.discipline_wander = SQRT(etemp + (dtemp - etemp) / AVG);
|
---|
1660 |
|
---|
1661 | VERB4 bb_error_msg("discipline freq_drift=%.9f(int:%ld corr:%e) wander=%f",
|
---|
1662 | G.discipline_freq_drift,
|
---|
1663 | (long)(G.discipline_freq_drift * 65536e6),
|
---|
1664 | freq_drift,
|
---|
1665 | G.discipline_wander);
|
---|
1666 | #endif
|
---|
1667 | VERB4 {
|
---|
1668 | memset(&tmx, 0, sizeof(tmx));
|
---|
1669 | if (adjtimex(&tmx) < 0)
|
---|
1670 | bb_perror_msg_and_die("adjtimex");
|
---|
1671 | bb_error_msg("p adjtimex freq:%ld offset:%+ld status:0x%x tc:%ld",
|
---|
1672 | tmx.freq, tmx.offset, tmx.status, tmx.constant);
|
---|
1673 | }
|
---|
1674 |
|
---|
1675 | memset(&tmx, 0, sizeof(tmx));
|
---|
1676 | #if 0
|
---|
1677 | //doesn't work, offset remains 0 (!) in kernel:
|
---|
1678 | //ntpd: set adjtimex freq:1786097 tmx.offset:77487
|
---|
1679 | //ntpd: prev adjtimex freq:1786097 tmx.offset:0
|
---|
1680 | //ntpd: cur adjtimex freq:1786097 tmx.offset:0
|
---|
1681 | tmx.modes = ADJ_FREQUENCY | ADJ_OFFSET;
|
---|
1682 | /* 65536 is one ppm */
|
---|
1683 | tmx.freq = G.discipline_freq_drift * 65536e6;
|
---|
1684 | #endif
|
---|
1685 | tmx.modes = ADJ_OFFSET | ADJ_STATUS | ADJ_TIMECONST;// | ADJ_MAXERROR | ADJ_ESTERROR;
|
---|
1686 | tmx.constant = (int)G.poll_exp - 4;
|
---|
1687 | /* EXPERIMENTAL.
|
---|
1688 | * The below if statement should be unnecessary, but...
|
---|
1689 | * It looks like Linux kernel's PLL is far too gentle in changing
|
---|
1690 | * tmx.freq in response to clock offset. Offset keeps growing
|
---|
1691 | * and eventually we fall back to smaller poll intervals.
|
---|
1692 | * We can make correction more agressive (about x2) by supplying
|
---|
1693 | * PLL time constant which is one less than the real one.
|
---|
1694 | * To be on a safe side, let's do it only if offset is significantly
|
---|
1695 | * larger than jitter.
|
---|
1696 | */
|
---|
1697 | if (G.offset_to_jitter_ratio >= TIMECONST_HACK_GATE)
|
---|
1698 | tmx.constant--;
|
---|
1699 | tmx.offset = (long)(offset * 1000000); /* usec */
|
---|
1700 | if (SLEW_THRESHOLD < STEP_THRESHOLD) {
|
---|
1701 | if (tmx.offset > (long)(SLEW_THRESHOLD * 1000000)) {
|
---|
1702 | tmx.offset = (long)(SLEW_THRESHOLD * 1000000);
|
---|
1703 | tmx.constant--;
|
---|
1704 | }
|
---|
1705 | if (tmx.offset < -(long)(SLEW_THRESHOLD * 1000000)) {
|
---|
1706 | tmx.offset = -(long)(SLEW_THRESHOLD * 1000000);
|
---|
1707 | tmx.constant--;
|
---|
1708 | }
|
---|
1709 | }
|
---|
1710 | if (tmx.constant < 0)
|
---|
1711 | tmx.constant = 0;
|
---|
1712 |
|
---|
1713 | tmx.status = STA_PLL;
|
---|
1714 | if (G.ntp_status & LI_PLUSSEC)
|
---|
1715 | tmx.status |= STA_INS;
|
---|
1716 | if (G.ntp_status & LI_MINUSSEC)
|
---|
1717 | tmx.status |= STA_DEL;
|
---|
1718 |
|
---|
1719 | //tmx.esterror = (uint32_t)(clock_jitter * 1e6);
|
---|
1720 | //tmx.maxerror = (uint32_t)((sys_rootdelay / 2 + sys_rootdisp) * 1e6);
|
---|
1721 | rc = adjtimex(&tmx);
|
---|
1722 | if (rc < 0)
|
---|
1723 | bb_perror_msg_and_die("adjtimex");
|
---|
1724 | /* NB: here kernel returns constant == G.poll_exp, not == G.poll_exp - 4.
|
---|
1725 | * Not sure why. Perhaps it is normal.
|
---|
1726 | */
|
---|
1727 | VERB4 bb_error_msg("adjtimex:%d freq:%ld offset:%+ld status:0x%x",
|
---|
1728 | rc, tmx.freq, tmx.offset, tmx.status);
|
---|
1729 | G.kernel_freq_drift = tmx.freq / 65536;
|
---|
1730 | VERB2 bb_error_msg("update from:%s offset:%+f delay:%f jitter:%f clock drift:%+.3fppm tc:%d",
|
---|
1731 | p->p_dotted,
|
---|
1732 | offset,
|
---|
1733 | p->lastpkt_delay,
|
---|
1734 | G.discipline_jitter,
|
---|
1735 | (double)tmx.freq / 65536,
|
---|
1736 | (int)tmx.constant
|
---|
1737 | );
|
---|
1738 |
|
---|
1739 | return 1; /* "ok to increase poll interval" */
|
---|
1740 | }
|
---|
1741 |
|
---|
1742 |
|
---|
1743 | /*
|
---|
1744 | * We've got a new reply packet from a peer, process it
|
---|
1745 | * (helpers first)
|
---|
1746 | */
|
---|
1747 | static unsigned
|
---|
1748 | poll_interval(int upper_bound)
|
---|
1749 | {
|
---|
1750 | unsigned interval, r, mask;
|
---|
1751 | interval = 1 << G.poll_exp;
|
---|
1752 | if (interval > upper_bound)
|
---|
1753 | interval = upper_bound;
|
---|
1754 | mask = ((interval-1) >> 4) | 1;
|
---|
1755 | r = rand();
|
---|
1756 | interval += r & mask; /* ~ random(0..1) * interval/16 */
|
---|
1757 | VERB4 bb_error_msg("chose poll interval:%u (poll_exp:%d)", interval, G.poll_exp);
|
---|
1758 | return interval;
|
---|
1759 | }
|
---|
1760 | static void
|
---|
1761 | adjust_poll(int count)
|
---|
1762 | {
|
---|
1763 | G.polladj_count += count;
|
---|
1764 | if (G.polladj_count > POLLADJ_LIMIT) {
|
---|
1765 | G.polladj_count = 0;
|
---|
1766 | if (G.poll_exp < MAXPOLL) {
|
---|
1767 | G.poll_exp++;
|
---|
1768 | VERB4 bb_error_msg("polladj: discipline_jitter:%f ++poll_exp=%d",
|
---|
1769 | G.discipline_jitter, G.poll_exp);
|
---|
1770 | }
|
---|
1771 | } else if (G.polladj_count < -POLLADJ_LIMIT || (count < 0 && G.poll_exp > BIGPOLL)) {
|
---|
1772 | G.polladj_count = 0;
|
---|
1773 | if (G.poll_exp > MINPOLL) {
|
---|
1774 | llist_t *item;
|
---|
1775 |
|
---|
1776 | G.poll_exp--;
|
---|
1777 | /* Correct p->next_action_time in each peer
|
---|
1778 | * which waits for sending, so that they send earlier.
|
---|
1779 | * Old pp->next_action_time are on the order
|
---|
1780 | * of t + (1 << old_poll_exp) + small_random,
|
---|
1781 | * we simply need to subtract ~half of that.
|
---|
1782 | */
|
---|
1783 | for (item = G.ntp_peers; item != NULL; item = item->link) {
|
---|
1784 | peer_t *pp = (peer_t *) item->data;
|
---|
1785 | if (pp->p_fd < 0)
|
---|
1786 | pp->next_action_time -= (1 << G.poll_exp);
|
---|
1787 | }
|
---|
1788 | VERB4 bb_error_msg("polladj: discipline_jitter:%f --poll_exp=%d",
|
---|
1789 | G.discipline_jitter, G.poll_exp);
|
---|
1790 | }
|
---|
1791 | } else {
|
---|
1792 | VERB4 bb_error_msg("polladj: count:%d", G.polladj_count);
|
---|
1793 | }
|
---|
1794 | }
|
---|
1795 | static NOINLINE void
|
---|
1796 | recv_and_process_peer_pkt(peer_t *p)
|
---|
1797 | {
|
---|
1798 | int rc;
|
---|
1799 | ssize_t size;
|
---|
1800 | msg_t msg;
|
---|
1801 | double T1, T2, T3, T4;
|
---|
1802 | double offset;
|
---|
1803 | double prev_delay, delay;
|
---|
1804 | unsigned interval;
|
---|
1805 | datapoint_t *datapoint;
|
---|
1806 | peer_t *q;
|
---|
1807 |
|
---|
1808 | offset = 0;
|
---|
1809 |
|
---|
1810 | /* We can recvfrom here and check from.IP, but some multihomed
|
---|
1811 | * ntp servers reply from their *other IP*.
|
---|
1812 | * TODO: maybe we should check at least what we can: from.port == 123?
|
---|
1813 | */
|
---|
1814 | recv_again:
|
---|
1815 | size = recv(p->p_fd, &msg, sizeof(msg), MSG_DONTWAIT);
|
---|
1816 | if (size < 0) {
|
---|
1817 | if (errno == EINTR)
|
---|
1818 | /* Signal caught */
|
---|
1819 | goto recv_again;
|
---|
1820 | if (errno == EAGAIN)
|
---|
1821 | /* There was no packet after all
|
---|
1822 | * (poll() returning POLLIN for a fd
|
---|
1823 | * is not a ironclad guarantee that data is there)
|
---|
1824 | */
|
---|
1825 | return;
|
---|
1826 | /*
|
---|
1827 | * If you need a different handling for a specific
|
---|
1828 | * errno, always explain it in comment.
|
---|
1829 | */
|
---|
1830 | bb_perror_msg_and_die("recv(%s) error", p->p_dotted);
|
---|
1831 | }
|
---|
1832 |
|
---|
1833 | if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
|
---|
1834 | bb_error_msg("malformed packet received from %s", p->p_dotted);
|
---|
1835 | return;
|
---|
1836 | }
|
---|
1837 |
|
---|
1838 | if (msg.m_orgtime.int_partl != p->p_xmt_msg.m_xmttime.int_partl
|
---|
1839 | || msg.m_orgtime.fractionl != p->p_xmt_msg.m_xmttime.fractionl
|
---|
1840 | ) {
|
---|
1841 | /* Somebody else's packet */
|
---|
1842 | return;
|
---|
1843 | }
|
---|
1844 |
|
---|
1845 | /* We do not expect any more packets from this peer for now.
|
---|
1846 | * Closing the socket informs kernel about it.
|
---|
1847 | * We open a new socket when we send a new query.
|
---|
1848 | */
|
---|
1849 | close(p->p_fd);
|
---|
1850 | p->p_fd = -1;
|
---|
1851 |
|
---|
1852 | if ((msg.m_status & LI_ALARM) == LI_ALARM
|
---|
1853 | || msg.m_stratum == 0
|
---|
1854 | || msg.m_stratum > NTP_MAXSTRATUM
|
---|
1855 | ) {
|
---|
1856 | bb_error_msg("reply from %s: peer is unsynced", p->p_dotted);
|
---|
1857 | /*
|
---|
1858 | * Stratum 0 responses may have commands in 32-bit m_refid field:
|
---|
1859 | * "DENY", "RSTR" - peer does not like us at all,
|
---|
1860 | * "RATE" - peer is overloaded, reduce polling freq.
|
---|
1861 | * If poll interval is small, increase it.
|
---|
1862 | */
|
---|
1863 | if (G.poll_exp < BIGPOLL)
|
---|
1864 | goto increase_interval;
|
---|
1865 | goto pick_normal_interval;
|
---|
1866 | }
|
---|
1867 |
|
---|
1868 | // /* Verify valid root distance */
|
---|
1869 | // if (msg.m_rootdelay / 2 + msg.m_rootdisp >= MAXDISP || p->lastpkt_reftime > msg.m_xmt)
|
---|
1870 | // return; /* invalid header values */
|
---|
1871 |
|
---|
1872 | /*
|
---|
1873 | * From RFC 2030 (with a correction to the delay math):
|
---|
1874 | *
|
---|
1875 | * Timestamp Name ID When Generated
|
---|
1876 | * ------------------------------------------------------------
|
---|
1877 | * Originate Timestamp T1 time request sent by client
|
---|
1878 | * Receive Timestamp T2 time request received by server
|
---|
1879 | * Transmit Timestamp T3 time reply sent by server
|
---|
1880 | * Destination Timestamp T4 time reply received by client
|
---|
1881 | *
|
---|
1882 | * The roundtrip delay and local clock offset are defined as
|
---|
1883 | *
|
---|
1884 | * delay = (T4 - T1) - (T3 - T2); offset = ((T2 - T1) + (T3 - T4)) / 2
|
---|
1885 | */
|
---|
1886 | T1 = p->p_xmttime;
|
---|
1887 | T2 = lfp_to_d(msg.m_rectime);
|
---|
1888 | T3 = lfp_to_d(msg.m_xmttime);
|
---|
1889 | T4 = G.cur_time;
|
---|
1890 |
|
---|
1891 | /* The delay calculation is a special case. In cases where the
|
---|
1892 | * server and client clocks are running at different rates and
|
---|
1893 | * with very fast networks, the delay can appear negative. In
|
---|
1894 | * order to avoid violating the Principle of Least Astonishment,
|
---|
1895 | * the delay is clamped not less than the system precision.
|
---|
1896 | */
|
---|
1897 | delay = (T4 - T1) - (T3 - T2);
|
---|
1898 | if (delay < G_precision_sec)
|
---|
1899 | delay = G_precision_sec;
|
---|
1900 | /*
|
---|
1901 | * If this packet's delay is much bigger than the last one,
|
---|
1902 | * it's better to just ignore it than use its much less precise value.
|
---|
1903 | */
|
---|
1904 | prev_delay = p->p_raw_delay;
|
---|
1905 | p->p_raw_delay = delay;
|
---|
1906 | if (p->reachable_bits && delay > prev_delay * BAD_DELAY_GROWTH) {
|
---|
1907 | bb_error_msg("reply from %s: delay %f is too high, ignoring", p->p_dotted, delay);
|
---|
1908 | goto pick_normal_interval;
|
---|
1909 | }
|
---|
1910 |
|
---|
1911 | p->lastpkt_delay = delay;
|
---|
1912 | p->lastpkt_recv_time = T4;
|
---|
1913 | VERB6 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time);
|
---|
1914 | p->lastpkt_status = msg.m_status;
|
---|
1915 | p->lastpkt_stratum = msg.m_stratum;
|
---|
1916 | p->lastpkt_rootdelay = sfp_to_d(msg.m_rootdelay);
|
---|
1917 | p->lastpkt_rootdisp = sfp_to_d(msg.m_rootdisp);
|
---|
1918 | p->lastpkt_refid = msg.m_refid;
|
---|
1919 |
|
---|
1920 | p->datapoint_idx = p->reachable_bits ? (p->datapoint_idx + 1) % NUM_DATAPOINTS : 0;
|
---|
1921 | datapoint = &p->filter_datapoint[p->datapoint_idx];
|
---|
1922 | datapoint->d_recv_time = T4;
|
---|
1923 | datapoint->d_offset = offset = ((T2 - T1) + (T3 - T4)) / 2;
|
---|
1924 | datapoint->d_dispersion = LOG2D(msg.m_precision_exp) + G_precision_sec;
|
---|
1925 | if (!p->reachable_bits) {
|
---|
1926 | /* 1st datapoint ever - replicate offset in every element */
|
---|
1927 | int i;
|
---|
1928 | for (i = 0; i < NUM_DATAPOINTS; i++) {
|
---|
1929 | p->filter_datapoint[i].d_offset = offset;
|
---|
1930 | }
|
---|
1931 | }
|
---|
1932 |
|
---|
1933 | p->reachable_bits |= 1;
|
---|
1934 | if ((MAX_VERBOSE && G.verbose) || (option_mask32 & OPT_w)) {
|
---|
1935 | bb_error_msg("reply from %s: offset:%+f delay:%f status:0x%02x strat:%d refid:0x%08x rootdelay:%f reach:0x%02x",
|
---|
1936 | p->p_dotted,
|
---|
1937 | offset,
|
---|
1938 | p->lastpkt_delay,
|
---|
1939 | p->lastpkt_status,
|
---|
1940 | p->lastpkt_stratum,
|
---|
1941 | p->lastpkt_refid,
|
---|
1942 | p->lastpkt_rootdelay,
|
---|
1943 | p->reachable_bits
|
---|
1944 | /* not shown: m_ppoll, m_precision_exp, m_rootdisp,
|
---|
1945 | * m_reftime, m_orgtime, m_rectime, m_xmttime
|
---|
1946 | */
|
---|
1947 | );
|
---|
1948 | }
|
---|
1949 |
|
---|
1950 | /* Muck with statictics and update the clock */
|
---|
1951 | filter_datapoints(p);
|
---|
1952 | q = select_and_cluster();
|
---|
1953 | rc = 0;
|
---|
1954 | if (q) {
|
---|
1955 | if (!(option_mask32 & OPT_w)) {
|
---|
1956 | rc = update_local_clock(q);
|
---|
1957 | #if 0
|
---|
1958 | //Disabled this because there is a case where largish offsets
|
---|
1959 | //are unavoidable: if network round-trip delay is, say, ~0.6s,
|
---|
1960 | //error in offset estimation would be ~delay/2 ~= 0.3s.
|
---|
1961 | //Thus, offsets will be usually in -0.3...0.3s range.
|
---|
1962 | //In this case, this code would keep poll interval small,
|
---|
1963 | //but it won't be helping.
|
---|
1964 | //BIGOFF check below deals with a case of seeing multi-second offsets.
|
---|
1965 |
|
---|
1966 | /* If drift is dangerously large, immediately
|
---|
1967 | * drop poll interval one step down.
|
---|
1968 | */
|
---|
1969 | if (fabs(q->filter_offset) >= POLLDOWN_OFFSET) {
|
---|
1970 | VERB4 bb_error_msg("offset:%+f > POLLDOWN_OFFSET", q->filter_offset);
|
---|
1971 | adjust_poll(-POLLADJ_LIMIT * 3);
|
---|
1972 | rc = 0;
|
---|
1973 | }
|
---|
1974 | #endif
|
---|
1975 | }
|
---|
1976 | } else {
|
---|
1977 | /* No peer selected.
|
---|
1978 | * If poll interval is small, increase it.
|
---|
1979 | */
|
---|
1980 | if (G.poll_exp < BIGPOLL)
|
---|
1981 | goto increase_interval;
|
---|
1982 | }
|
---|
1983 |
|
---|
1984 | if (rc != 0) {
|
---|
1985 | /* Adjust the poll interval by comparing the current offset
|
---|
1986 | * with the clock jitter. If the offset is less than
|
---|
1987 | * the clock jitter times a constant, then the averaging interval
|
---|
1988 | * is increased, otherwise it is decreased. A bit of hysteresis
|
---|
1989 | * helps calm the dance. Works best using burst mode.
|
---|
1990 | */
|
---|
1991 | if (rc > 0 && G.offset_to_jitter_ratio <= POLLADJ_GATE) {
|
---|
1992 | /* was += G.poll_exp but it is a bit
|
---|
1993 | * too optimistic for my taste at high poll_exp's */
|
---|
1994 | increase_interval:
|
---|
1995 | adjust_poll(MINPOLL);
|
---|
1996 | } else {
|
---|
1997 | VERB3 if (rc > 0)
|
---|
1998 | bb_error_msg("want smaller interval: offset/jitter = %u",
|
---|
1999 | G.offset_to_jitter_ratio);
|
---|
2000 | adjust_poll(-G.poll_exp * 2);
|
---|
2001 | }
|
---|
2002 | }
|
---|
2003 |
|
---|
2004 | /* Decide when to send new query for this peer */
|
---|
2005 | pick_normal_interval:
|
---|
2006 | interval = poll_interval(INT_MAX);
|
---|
2007 | if (fabs(offset) >= BIGOFF && interval > BIGOFF_INTERVAL) {
|
---|
2008 | /* If we are synced, offsets are less than SLEW_THRESHOLD,
|
---|
2009 | * or at the very least not much larger than it.
|
---|
2010 | * Now we see a largish one.
|
---|
2011 | * Either this peer is feeling bad, or packet got corrupted,
|
---|
2012 | * or _our_ clock is wrong now and _all_ peers will show similar
|
---|
2013 | * largish offsets too.
|
---|
2014 | * I observed this with laptop suspend stopping clock.
|
---|
2015 | * In any case, it makes sense to make next request soonish:
|
---|
2016 | * cases 1 and 2: get a better datapoint,
|
---|
2017 | * case 3: allows to resync faster.
|
---|
2018 | */
|
---|
2019 | interval = BIGOFF_INTERVAL;
|
---|
2020 | }
|
---|
2021 |
|
---|
2022 | set_next(p, interval);
|
---|
2023 | }
|
---|
2024 |
|
---|
2025 | #if ENABLE_FEATURE_NTPD_SERVER
|
---|
2026 | static NOINLINE void
|
---|
2027 | recv_and_process_client_pkt(void /*int fd*/)
|
---|
2028 | {
|
---|
2029 | ssize_t size;
|
---|
2030 | //uint8_t version;
|
---|
2031 | len_and_sockaddr *to;
|
---|
2032 | struct sockaddr *from;
|
---|
2033 | msg_t msg;
|
---|
2034 | uint8_t query_status;
|
---|
2035 | l_fixedpt_t query_xmttime;
|
---|
2036 |
|
---|
2037 | to = get_sock_lsa(G_listen_fd);
|
---|
2038 | from = xzalloc(to->len);
|
---|
2039 |
|
---|
2040 | size = recv_from_to(G_listen_fd, &msg, sizeof(msg), MSG_DONTWAIT, from, &to->u.sa, to->len);
|
---|
2041 | if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
|
---|
2042 | char *addr;
|
---|
2043 | if (size < 0) {
|
---|
2044 | if (errno == EAGAIN)
|
---|
2045 | goto bail;
|
---|
2046 | bb_perror_msg_and_die("recv");
|
---|
2047 | }
|
---|
2048 | addr = xmalloc_sockaddr2dotted_noport(from);
|
---|
2049 | bb_error_msg("malformed packet received from %s: size %u", addr, (int)size);
|
---|
2050 | free(addr);
|
---|
2051 | goto bail;
|
---|
2052 | }
|
---|
2053 |
|
---|
2054 | /* Respond only to client and symmetric active packets */
|
---|
2055 | if ((msg.m_status & MODE_MASK) != MODE_CLIENT
|
---|
2056 | && (msg.m_status & MODE_MASK) != MODE_SYM_ACT
|
---|
2057 | ) {
|
---|
2058 | goto bail;
|
---|
2059 | }
|
---|
2060 |
|
---|
2061 | query_status = msg.m_status;
|
---|
2062 | query_xmttime = msg.m_xmttime;
|
---|
2063 |
|
---|
2064 | /* Build a reply packet */
|
---|
2065 | memset(&msg, 0, sizeof(msg));
|
---|
2066 | msg.m_status = G.stratum < MAXSTRAT ? (G.ntp_status & LI_MASK) : LI_ALARM;
|
---|
2067 | msg.m_status |= (query_status & VERSION_MASK);
|
---|
2068 | msg.m_status |= ((query_status & MODE_MASK) == MODE_CLIENT) ?
|
---|
2069 | MODE_SERVER : MODE_SYM_PAS;
|
---|
2070 | msg.m_stratum = G.stratum;
|
---|
2071 | msg.m_ppoll = G.poll_exp;
|
---|
2072 | msg.m_precision_exp = G_precision_exp;
|
---|
2073 | /* this time was obtained between poll() and recv() */
|
---|
2074 | msg.m_rectime = d_to_lfp(G.cur_time);
|
---|
2075 | msg.m_xmttime = d_to_lfp(gettime1900d()); /* this instant */
|
---|
2076 | if (G.peer_cnt == 0) {
|
---|
2077 | /* we have no peers: "stratum 1 server" mode. reftime = our own time */
|
---|
2078 | G.reftime = G.cur_time;
|
---|
2079 | }
|
---|
2080 | msg.m_reftime = d_to_lfp(G.reftime);
|
---|
2081 | msg.m_orgtime = query_xmttime;
|
---|
2082 | msg.m_rootdelay = d_to_sfp(G.rootdelay);
|
---|
2083 | //simple code does not do this, fix simple code!
|
---|
2084 | msg.m_rootdisp = d_to_sfp(G.rootdisp);
|
---|
2085 | //version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */
|
---|
2086 | msg.m_refid = G.refid; // (version > (3 << VERSION_SHIFT)) ? G.refid : G.refid3;
|
---|
2087 |
|
---|
2088 | /* We reply from the local address packet was sent to,
|
---|
2089 | * this makes to/from look swapped here: */
|
---|
2090 | do_sendto(G_listen_fd,
|
---|
2091 | /*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len,
|
---|
2092 | &msg, size);
|
---|
2093 |
|
---|
2094 | bail:
|
---|
2095 | free(to);
|
---|
2096 | free(from);
|
---|
2097 | }
|
---|
2098 | #endif
|
---|
2099 |
|
---|
2100 | /* Upstream ntpd's options:
|
---|
2101 | *
|
---|
2102 | * -4 Force DNS resolution of host names to the IPv4 namespace.
|
---|
2103 | * -6 Force DNS resolution of host names to the IPv6 namespace.
|
---|
2104 | * -a Require cryptographic authentication for broadcast client,
|
---|
2105 | * multicast client and symmetric passive associations.
|
---|
2106 | * This is the default.
|
---|
2107 | * -A Do not require cryptographic authentication for broadcast client,
|
---|
2108 | * multicast client and symmetric passive associations.
|
---|
2109 | * This is almost never a good idea.
|
---|
2110 | * -b Enable the client to synchronize to broadcast servers.
|
---|
2111 | * -c conffile
|
---|
2112 | * Specify the name and path of the configuration file,
|
---|
2113 | * default /etc/ntp.conf
|
---|
2114 | * -d Specify debugging mode. This option may occur more than once,
|
---|
2115 | * with each occurrence indicating greater detail of display.
|
---|
2116 | * -D level
|
---|
2117 | * Specify debugging level directly.
|
---|
2118 | * -f driftfile
|
---|
2119 | * Specify the name and path of the frequency file.
|
---|
2120 | * This is the same operation as the "driftfile FILE"
|
---|
2121 | * configuration command.
|
---|
2122 | * -g Normally, ntpd exits with a message to the system log
|
---|
2123 | * if the offset exceeds the panic threshold, which is 1000 s
|
---|
2124 | * by default. This option allows the time to be set to any value
|
---|
2125 | * without restriction; however, this can happen only once.
|
---|
2126 | * If the threshold is exceeded after that, ntpd will exit
|
---|
2127 | * with a message to the system log. This option can be used
|
---|
2128 | * with the -q and -x options. See the tinker command for other options.
|
---|
2129 | * -i jaildir
|
---|
2130 | * Chroot the server to the directory jaildir. This option also implies
|
---|
2131 | * that the server attempts to drop root privileges at startup
|
---|
2132 | * (otherwise, chroot gives very little additional security).
|
---|
2133 | * You may need to also specify a -u option.
|
---|
2134 | * -k keyfile
|
---|
2135 | * Specify the name and path of the symmetric key file,
|
---|
2136 | * default /etc/ntp/keys. This is the same operation
|
---|
2137 | * as the "keys FILE" configuration command.
|
---|
2138 | * -l logfile
|
---|
2139 | * Specify the name and path of the log file. The default
|
---|
2140 | * is the system log file. This is the same operation as
|
---|
2141 | * the "logfile FILE" configuration command.
|
---|
2142 | * -L Do not listen to virtual IPs. The default is to listen.
|
---|
2143 | * -n Don't fork.
|
---|
2144 | * -N To the extent permitted by the operating system,
|
---|
2145 | * run the ntpd at the highest priority.
|
---|
2146 | * -p pidfile
|
---|
2147 | * Specify the name and path of the file used to record the ntpd
|
---|
2148 | * process ID. This is the same operation as the "pidfile FILE"
|
---|
2149 | * configuration command.
|
---|
2150 | * -P priority
|
---|
2151 | * To the extent permitted by the operating system,
|
---|
2152 | * run the ntpd at the specified priority.
|
---|
2153 | * -q Exit the ntpd just after the first time the clock is set.
|
---|
2154 | * This behavior mimics that of the ntpdate program, which is
|
---|
2155 | * to be retired. The -g and -x options can be used with this option.
|
---|
2156 | * Note: The kernel time discipline is disabled with this option.
|
---|
2157 | * -r broadcastdelay
|
---|
2158 | * Specify the default propagation delay from the broadcast/multicast
|
---|
2159 | * server to this client. This is necessary only if the delay
|
---|
2160 | * cannot be computed automatically by the protocol.
|
---|
2161 | * -s statsdir
|
---|
2162 | * Specify the directory path for files created by the statistics
|
---|
2163 | * facility. This is the same operation as the "statsdir DIR"
|
---|
2164 | * configuration command.
|
---|
2165 | * -t key
|
---|
2166 | * Add a key number to the trusted key list. This option can occur
|
---|
2167 | * more than once.
|
---|
2168 | * -u user[:group]
|
---|
2169 | * Specify a user, and optionally a group, to switch to.
|
---|
2170 | * -v variable
|
---|
2171 | * -V variable
|
---|
2172 | * Add a system variable listed by default.
|
---|
2173 | * -x Normally, the time is slewed if the offset is less than the step
|
---|
2174 | * threshold, which is 128 ms by default, and stepped if above
|
---|
2175 | * the threshold. This option sets the threshold to 600 s, which is
|
---|
2176 | * well within the accuracy window to set the clock manually.
|
---|
2177 | * Note: since the slew rate of typical Unix kernels is limited
|
---|
2178 | * to 0.5 ms/s, each second of adjustment requires an amortization
|
---|
2179 | * interval of 2000 s. Thus, an adjustment as much as 600 s
|
---|
2180 | * will take almost 14 days to complete. This option can be used
|
---|
2181 | * with the -g and -q options. See the tinker command for other options.
|
---|
2182 | * Note: The kernel time discipline is disabled with this option.
|
---|
2183 | */
|
---|
2184 |
|
---|
2185 | /* By doing init in a separate function we decrease stack usage
|
---|
2186 | * in main loop.
|
---|
2187 | */
|
---|
2188 | static NOINLINE void ntp_init(char **argv)
|
---|
2189 | {
|
---|
2190 | unsigned opts;
|
---|
2191 | llist_t *peers;
|
---|
2192 |
|
---|
2193 | srand(getpid());
|
---|
2194 |
|
---|
2195 | if (getuid())
|
---|
2196 | bb_error_msg_and_die(bb_msg_you_must_be_root);
|
---|
2197 |
|
---|
2198 | /* Set some globals */
|
---|
2199 | G.discipline_jitter = G_precision_sec;
|
---|
2200 | G.stratum = MAXSTRAT;
|
---|
2201 | if (BURSTPOLL != 0)
|
---|
2202 | G.poll_exp = BURSTPOLL; /* speeds up initial sync */
|
---|
2203 | G.last_script_run = G.reftime = G.last_update_recv_time = gettime1900d(); /* sets G.cur_time too */
|
---|
2204 |
|
---|
2205 | /* Parse options */
|
---|
2206 | peers = NULL;
|
---|
2207 | opt_complementary = "dd:p::wn" /* -d: counter; -p: list; -w implies -n */
|
---|
2208 | IF_FEATURE_NTPD_SERVER(":Il"); /* -I implies -l */
|
---|
2209 | opts = getopt32(argv,
|
---|
2210 | "nqNx" /* compat */
|
---|
2211 | "wp:S:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
|
---|
2212 | IF_FEATURE_NTPD_SERVER("I:") /* compat */
|
---|
2213 | "d" /* compat */
|
---|
2214 | "46aAbgL", /* compat, ignored */
|
---|
2215 | &peers,&G.script_name,
|
---|
2216 | #if ENABLE_FEATURE_NTPD_SERVER
|
---|
2217 | &G.if_name,
|
---|
2218 | #endif
|
---|
2219 | &G.verbose);
|
---|
2220 |
|
---|
2221 | // if (opts & OPT_x) /* disable stepping, only slew is allowed */
|
---|
2222 | // G.time_was_stepped = 1;
|
---|
2223 | if (peers) {
|
---|
2224 | while (peers)
|
---|
2225 | add_peers(llist_pop(&peers));
|
---|
2226 | }
|
---|
2227 | #if ENABLE_FEATURE_NTPD_CONF
|
---|
2228 | else {
|
---|
2229 | parser_t *parser;
|
---|
2230 | char *token[3];
|
---|
2231 |
|
---|
2232 | parser = config_open("/etc/ntp.conf");
|
---|
2233 | while (config_read(parser, token, 3, 1, "# \t", PARSE_NORMAL)) {
|
---|
2234 | if (strcmp(token[0], "server") == 0 && token[1]) {
|
---|
2235 | add_peers(token[1]);
|
---|
2236 | continue;
|
---|
2237 | }
|
---|
2238 | bb_error_msg("skipping %s:%u: unimplemented command '%s'",
|
---|
2239 | "/etc/ntp.conf", parser->lineno, token[0]
|
---|
2240 | );
|
---|
2241 | }
|
---|
2242 | config_close(parser);
|
---|
2243 | }
|
---|
2244 | #endif
|
---|
2245 | if (G.peer_cnt == 0) {
|
---|
2246 | if (!(opts & OPT_l))
|
---|
2247 | bb_show_usage();
|
---|
2248 | /* -l but no peers: "stratum 1 server" mode */
|
---|
2249 | G.stratum = 1;
|
---|
2250 | }
|
---|
2251 | #if ENABLE_FEATURE_NTPD_SERVER
|
---|
2252 | G_listen_fd = -1;
|
---|
2253 | if (opts & OPT_l) {
|
---|
2254 | G_listen_fd = create_and_bind_dgram_or_die(NULL, 123);
|
---|
2255 | if (opts & OPT_I) {
|
---|
2256 | if (setsockopt_bindtodevice(G_listen_fd, G.if_name))
|
---|
2257 | xfunc_die();
|
---|
2258 | }
|
---|
2259 | socket_want_pktinfo(G_listen_fd);
|
---|
2260 | setsockopt_int(G_listen_fd, IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY);
|
---|
2261 | }
|
---|
2262 | #endif
|
---|
2263 | if (!(opts & OPT_n)) {
|
---|
2264 | bb_daemonize_or_rexec(DAEMON_DEVNULL_STDIO, argv);
|
---|
2265 | logmode = LOGMODE_NONE;
|
---|
2266 | }
|
---|
2267 | /* I hesitate to set -20 prio. -15 should be high enough for timekeeping */
|
---|
2268 | if (opts & OPT_N)
|
---|
2269 | setpriority(PRIO_PROCESS, 0, -15);
|
---|
2270 |
|
---|
2271 | /* If network is up, syncronization occurs in ~10 seconds.
|
---|
2272 | * We give "ntpd -q" 10 seconds to get first reply,
|
---|
2273 | * then another 50 seconds to finish syncing.
|
---|
2274 | *
|
---|
2275 | * I tested ntpd 4.2.6p1 and apparently it never exits
|
---|
2276 | * (will try forever), but it does not feel right.
|
---|
2277 | * The goal of -q is to act like ntpdate: set time
|
---|
2278 | * after a reasonably small period of polling, or fail.
|
---|
2279 | */
|
---|
2280 | if (opts & OPT_q) {
|
---|
2281 | option_mask32 |= OPT_qq;
|
---|
2282 | alarm(10);
|
---|
2283 | }
|
---|
2284 |
|
---|
2285 | bb_signals(0
|
---|
2286 | | (1 << SIGTERM)
|
---|
2287 | | (1 << SIGINT)
|
---|
2288 | | (1 << SIGALRM)
|
---|
2289 | , record_signo
|
---|
2290 | );
|
---|
2291 | bb_signals(0
|
---|
2292 | | (1 << SIGPIPE)
|
---|
2293 | | (1 << SIGCHLD)
|
---|
2294 | , SIG_IGN
|
---|
2295 | );
|
---|
2296 | }
|
---|
2297 |
|
---|
2298 | int ntpd_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
---|
2299 | int ntpd_main(int argc UNUSED_PARAM, char **argv)
|
---|
2300 | {
|
---|
2301 | #undef G
|
---|
2302 | struct globals G;
|
---|
2303 | struct pollfd *pfd;
|
---|
2304 | peer_t **idx2peer;
|
---|
2305 | unsigned cnt;
|
---|
2306 |
|
---|
2307 | memset(&G, 0, sizeof(G));
|
---|
2308 | SET_PTR_TO_GLOBALS(&G);
|
---|
2309 |
|
---|
2310 | ntp_init(argv);
|
---|
2311 |
|
---|
2312 | /* If ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */
|
---|
2313 | cnt = G.peer_cnt + ENABLE_FEATURE_NTPD_SERVER;
|
---|
2314 | idx2peer = xzalloc(sizeof(idx2peer[0]) * cnt);
|
---|
2315 | pfd = xzalloc(sizeof(pfd[0]) * cnt);
|
---|
2316 |
|
---|
2317 | /* Countdown: we never sync before we sent INITIAL_SAMPLES+1
|
---|
2318 | * packets to each peer.
|
---|
2319 | * NB: if some peer is not responding, we may end up sending
|
---|
2320 | * fewer packets to it and more to other peers.
|
---|
2321 | * NB2: sync usually happens using INITIAL_SAMPLES packets,
|
---|
2322 | * since last reply does not come back instantaneously.
|
---|
2323 | */
|
---|
2324 | cnt = G.peer_cnt * (INITIAL_SAMPLES + 1);
|
---|
2325 |
|
---|
2326 | write_pidfile(CONFIG_PID_FILE_PATH "/ntpd.pid");
|
---|
2327 |
|
---|
2328 | while (!bb_got_signal) {
|
---|
2329 | llist_t *item;
|
---|
2330 | unsigned i, j;
|
---|
2331 | int nfds, timeout;
|
---|
2332 | double nextaction;
|
---|
2333 |
|
---|
2334 | /* Nothing between here and poll() blocks for any significant time */
|
---|
2335 |
|
---|
2336 | nextaction = G.cur_time + 3600;
|
---|
2337 |
|
---|
2338 | i = 0;
|
---|
2339 | #if ENABLE_FEATURE_NTPD_SERVER
|
---|
2340 | if (G_listen_fd != -1) {
|
---|
2341 | pfd[0].fd = G_listen_fd;
|
---|
2342 | pfd[0].events = POLLIN;
|
---|
2343 | i++;
|
---|
2344 | }
|
---|
2345 | #endif
|
---|
2346 | /* Pass over peer list, send requests, time out on receives */
|
---|
2347 | for (item = G.ntp_peers; item != NULL; item = item->link) {
|
---|
2348 | peer_t *p = (peer_t *) item->data;
|
---|
2349 |
|
---|
2350 | if (p->next_action_time <= G.cur_time) {
|
---|
2351 | if (p->p_fd == -1) {
|
---|
2352 | /* Time to send new req */
|
---|
2353 | if (--cnt == 0) {
|
---|
2354 | VERB4 bb_error_msg("disabling burst mode");
|
---|
2355 | G.polladj_count = 0;
|
---|
2356 | G.poll_exp = MINPOLL;
|
---|
2357 | }
|
---|
2358 | send_query_to_peer(p);
|
---|
2359 | } else {
|
---|
2360 | /* Timed out waiting for reply */
|
---|
2361 | close(p->p_fd);
|
---|
2362 | p->p_fd = -1;
|
---|
2363 | /* If poll interval is small, increase it */
|
---|
2364 | if (G.poll_exp < BIGPOLL)
|
---|
2365 | adjust_poll(MINPOLL);
|
---|
2366 | timeout = poll_interval(NOREPLY_INTERVAL);
|
---|
2367 | bb_error_msg("timed out waiting for %s, reach 0x%02x, next query in %us",
|
---|
2368 | p->p_dotted, p->reachable_bits, timeout);
|
---|
2369 |
|
---|
2370 | /* What if don't see it because it changed its IP? */
|
---|
2371 | if (p->reachable_bits == 0)
|
---|
2372 | resolve_peer_hostname(p, /*loop_on_fail=*/ 0);
|
---|
2373 |
|
---|
2374 | set_next(p, timeout);
|
---|
2375 | }
|
---|
2376 | }
|
---|
2377 |
|
---|
2378 | if (p->next_action_time < nextaction)
|
---|
2379 | nextaction = p->next_action_time;
|
---|
2380 |
|
---|
2381 | if (p->p_fd >= 0) {
|
---|
2382 | /* Wait for reply from this peer */
|
---|
2383 | pfd[i].fd = p->p_fd;
|
---|
2384 | pfd[i].events = POLLIN;
|
---|
2385 | idx2peer[i] = p;
|
---|
2386 | i++;
|
---|
2387 | }
|
---|
2388 | }
|
---|
2389 |
|
---|
2390 | timeout = nextaction - G.cur_time;
|
---|
2391 | if (timeout < 0)
|
---|
2392 | timeout = 0;
|
---|
2393 | timeout++; /* (nextaction - G.cur_time) rounds down, compensating */
|
---|
2394 |
|
---|
2395 | /* Here we may block */
|
---|
2396 | VERB2 {
|
---|
2397 | if (i > (ENABLE_FEATURE_NTPD_SERVER && G_listen_fd != -1)) {
|
---|
2398 | /* We wait for at least one reply.
|
---|
2399 | * Poll for it, without wasting time for message.
|
---|
2400 | * Since replies often come under 1 second, this also
|
---|
2401 | * reduces clutter in logs.
|
---|
2402 | */
|
---|
2403 | nfds = poll(pfd, i, 1000);
|
---|
2404 | if (nfds != 0)
|
---|
2405 | goto did_poll;
|
---|
2406 | if (--timeout <= 0)
|
---|
2407 | goto did_poll;
|
---|
2408 | }
|
---|
2409 | bb_error_msg("poll:%us sockets:%u interval:%us", timeout, i, 1 << G.poll_exp);
|
---|
2410 | }
|
---|
2411 | nfds = poll(pfd, i, timeout * 1000);
|
---|
2412 | did_poll:
|
---|
2413 | gettime1900d(); /* sets G.cur_time */
|
---|
2414 | if (nfds <= 0) {
|
---|
2415 | if (!bb_got_signal /* poll wasn't interrupted by a signal */
|
---|
2416 | && G.cur_time - G.last_script_run > 11*60
|
---|
2417 | ) {
|
---|
2418 | /* Useful for updating battery-backed RTC and such */
|
---|
2419 | run_script("periodic", G.last_update_offset);
|
---|
2420 | gettime1900d(); /* sets G.cur_time */
|
---|
2421 | }
|
---|
2422 | goto check_unsync;
|
---|
2423 | }
|
---|
2424 |
|
---|
2425 | /* Process any received packets */
|
---|
2426 | j = 0;
|
---|
2427 | #if ENABLE_FEATURE_NTPD_SERVER
|
---|
2428 | if (G.listen_fd != -1) {
|
---|
2429 | if (pfd[0].revents /* & (POLLIN|POLLERR)*/) {
|
---|
2430 | nfds--;
|
---|
2431 | recv_and_process_client_pkt(/*G.listen_fd*/);
|
---|
2432 | gettime1900d(); /* sets G.cur_time */
|
---|
2433 | }
|
---|
2434 | j = 1;
|
---|
2435 | }
|
---|
2436 | #endif
|
---|
2437 | for (; nfds != 0 && j < i; j++) {
|
---|
2438 | if (pfd[j].revents /* & (POLLIN|POLLERR)*/) {
|
---|
2439 | /*
|
---|
2440 | * At init, alarm was set to 10 sec.
|
---|
2441 | * Now we did get a reply.
|
---|
2442 | * Increase timeout to 50 seconds to finish syncing.
|
---|
2443 | */
|
---|
2444 | if (option_mask32 & OPT_qq) {
|
---|
2445 | option_mask32 &= ~OPT_qq;
|
---|
2446 | alarm(50);
|
---|
2447 | }
|
---|
2448 | nfds--;
|
---|
2449 | recv_and_process_peer_pkt(idx2peer[j]);
|
---|
2450 | gettime1900d(); /* sets G.cur_time */
|
---|
2451 | }
|
---|
2452 | }
|
---|
2453 |
|
---|
2454 | check_unsync:
|
---|
2455 | if (G.ntp_peers && G.stratum != MAXSTRAT) {
|
---|
2456 | for (item = G.ntp_peers; item != NULL; item = item->link) {
|
---|
2457 | peer_t *p = (peer_t *) item->data;
|
---|
2458 | if (p->reachable_bits)
|
---|
2459 | goto have_reachable_peer;
|
---|
2460 | }
|
---|
2461 | /* No peer responded for last 8 packets, panic */
|
---|
2462 | clamp_pollexp_and_set_MAXSTRAT();
|
---|
2463 | run_script("unsync", 0.0);
|
---|
2464 | have_reachable_peer: ;
|
---|
2465 | }
|
---|
2466 | } /* while (!bb_got_signal) */
|
---|
2467 |
|
---|
2468 | remove_pidfile(CONFIG_PID_FILE_PATH "/ntpd.pid");
|
---|
2469 | kill_myself_with_sig(bb_got_signal);
|
---|
2470 | }
|
---|
2471 |
|
---|
2472 |
|
---|
2473 |
|
---|
2474 |
|
---|
2475 |
|
---|
2476 |
|
---|
2477 | /*** openntpd-4.6 uses only adjtime, not adjtimex ***/
|
---|
2478 |
|
---|
2479 | /*** ntp-4.2.6/ntpd/ntp_loopfilter.c - adjtimex usage ***/
|
---|
2480 |
|
---|
2481 | #if 0
|
---|
2482 | static double
|
---|
2483 | direct_freq(double fp_offset)
|
---|
2484 | {
|
---|
2485 | #ifdef KERNEL_PLL
|
---|
2486 | /*
|
---|
2487 | * If the kernel is enabled, we need the residual offset to
|
---|
2488 | * calculate the frequency correction.
|
---|
2489 | */
|
---|
2490 | if (pll_control && kern_enable) {
|
---|
2491 | memset(&ntv, 0, sizeof(ntv));
|
---|
2492 | ntp_adjtime(&ntv);
|
---|
2493 | #ifdef STA_NANO
|
---|
2494 | clock_offset = ntv.offset / 1e9;
|
---|
2495 | #else /* STA_NANO */
|
---|
2496 | clock_offset = ntv.offset / 1e6;
|
---|
2497 | #endif /* STA_NANO */
|
---|
2498 | drift_comp = FREQTOD(ntv.freq);
|
---|
2499 | }
|
---|
2500 | #endif /* KERNEL_PLL */
|
---|
2501 | set_freq((fp_offset - clock_offset) / (current_time - clock_epoch) + drift_comp);
|
---|
2502 | wander_resid = 0;
|
---|
2503 | return drift_comp;
|
---|
2504 | }
|
---|
2505 |
|
---|
2506 | static void
|
---|
2507 | set_freq(double freq) /* frequency update */
|
---|
2508 | {
|
---|
2509 | char tbuf[80];
|
---|
2510 |
|
---|
2511 | drift_comp = freq;
|
---|
2512 |
|
---|
2513 | #ifdef KERNEL_PLL
|
---|
2514 | /*
|
---|
2515 | * If the kernel is enabled, update the kernel frequency.
|
---|
2516 | */
|
---|
2517 | if (pll_control && kern_enable) {
|
---|
2518 | memset(&ntv, 0, sizeof(ntv));
|
---|
2519 | ntv.modes = MOD_FREQUENCY;
|
---|
2520 | ntv.freq = DTOFREQ(drift_comp);
|
---|
2521 | ntp_adjtime(&ntv);
|
---|
2522 | snprintf(tbuf, sizeof(tbuf), "kernel %.3f PPM", drift_comp * 1e6);
|
---|
2523 | report_event(EVNT_FSET, NULL, tbuf);
|
---|
2524 | } else {
|
---|
2525 | snprintf(tbuf, sizeof(tbuf), "ntpd %.3f PPM", drift_comp * 1e6);
|
---|
2526 | report_event(EVNT_FSET, NULL, tbuf);
|
---|
2527 | }
|
---|
2528 | #else /* KERNEL_PLL */
|
---|
2529 | snprintf(tbuf, sizeof(tbuf), "ntpd %.3f PPM", drift_comp * 1e6);
|
---|
2530 | report_event(EVNT_FSET, NULL, tbuf);
|
---|
2531 | #endif /* KERNEL_PLL */
|
---|
2532 | }
|
---|
2533 |
|
---|
2534 | ...
|
---|
2535 | ...
|
---|
2536 | ...
|
---|
2537 |
|
---|
2538 | #ifdef KERNEL_PLL
|
---|
2539 | /*
|
---|
2540 | * This code segment works when clock adjustments are made using
|
---|
2541 | * precision time kernel support and the ntp_adjtime() system
|
---|
2542 | * call. This support is available in Solaris 2.6 and later,
|
---|
2543 | * Digital Unix 4.0 and later, FreeBSD, Linux and specially
|
---|
2544 | * modified kernels for HP-UX 9 and Ultrix 4. In the case of the
|
---|
2545 | * DECstation 5000/240 and Alpha AXP, additional kernel
|
---|
2546 | * modifications provide a true microsecond clock and nanosecond
|
---|
2547 | * clock, respectively.
|
---|
2548 | *
|
---|
2549 | * Important note: The kernel discipline is used only if the
|
---|
2550 | * step threshold is less than 0.5 s, as anything higher can
|
---|
2551 | * lead to overflow problems. This might occur if some misguided
|
---|
2552 | * lad set the step threshold to something ridiculous.
|
---|
2553 | */
|
---|
2554 | if (pll_control && kern_enable) {
|
---|
2555 |
|
---|
2556 | #define MOD_BITS (MOD_OFFSET | MOD_MAXERROR | MOD_ESTERROR | MOD_STATUS | MOD_TIMECONST)
|
---|
2557 |
|
---|
2558 | /*
|
---|
2559 | * We initialize the structure for the ntp_adjtime()
|
---|
2560 | * system call. We have to convert everything to
|
---|
2561 | * microseconds or nanoseconds first. Do not update the
|
---|
2562 | * system variables if the ext_enable flag is set. In
|
---|
2563 | * this case, the external clock driver will update the
|
---|
2564 | * variables, which will be read later by the local
|
---|
2565 | * clock driver. Afterwards, remember the time and
|
---|
2566 | * frequency offsets for jitter and stability values and
|
---|
2567 | * to update the frequency file.
|
---|
2568 | */
|
---|
2569 | memset(&ntv, 0, sizeof(ntv));
|
---|
2570 | if (ext_enable) {
|
---|
2571 | ntv.modes = MOD_STATUS;
|
---|
2572 | } else {
|
---|
2573 | #ifdef STA_NANO
|
---|
2574 | ntv.modes = MOD_BITS | MOD_NANO;
|
---|
2575 | #else /* STA_NANO */
|
---|
2576 | ntv.modes = MOD_BITS;
|
---|
2577 | #endif /* STA_NANO */
|
---|
2578 | if (clock_offset < 0)
|
---|
2579 | dtemp = -.5;
|
---|
2580 | else
|
---|
2581 | dtemp = .5;
|
---|
2582 | #ifdef STA_NANO
|
---|
2583 | ntv.offset = (int32)(clock_offset * 1e9 + dtemp);
|
---|
2584 | ntv.constant = sys_poll;
|
---|
2585 | #else /* STA_NANO */
|
---|
2586 | ntv.offset = (int32)(clock_offset * 1e6 + dtemp);
|
---|
2587 | ntv.constant = sys_poll - 4;
|
---|
2588 | #endif /* STA_NANO */
|
---|
2589 | ntv.esterror = (u_int32)(clock_jitter * 1e6);
|
---|
2590 | ntv.maxerror = (u_int32)((sys_rootdelay / 2 + sys_rootdisp) * 1e6);
|
---|
2591 | ntv.status = STA_PLL;
|
---|
2592 |
|
---|
2593 | /*
|
---|
2594 | * Enable/disable the PPS if requested.
|
---|
2595 | */
|
---|
2596 | if (pps_enable) {
|
---|
2597 | if (!(pll_status & STA_PPSTIME))
|
---|
2598 | report_event(EVNT_KERN,
|
---|
2599 | NULL, "PPS enabled");
|
---|
2600 | ntv.status |= STA_PPSTIME | STA_PPSFREQ;
|
---|
2601 | } else {
|
---|
2602 | if (pll_status & STA_PPSTIME)
|
---|
2603 | report_event(EVNT_KERN,
|
---|
2604 | NULL, "PPS disabled");
|
---|
2605 | ntv.status &= ~(STA_PPSTIME | STA_PPSFREQ);
|
---|
2606 | }
|
---|
2607 | if (sys_leap == LEAP_ADDSECOND)
|
---|
2608 | ntv.status |= STA_INS;
|
---|
2609 | else if (sys_leap == LEAP_DELSECOND)
|
---|
2610 | ntv.status |= STA_DEL;
|
---|
2611 | }
|
---|
2612 |
|
---|
2613 | /*
|
---|
2614 | * Pass the stuff to the kernel. If it squeals, turn off
|
---|
2615 | * the pps. In any case, fetch the kernel offset,
|
---|
2616 | * frequency and jitter.
|
---|
2617 | */
|
---|
2618 | if (ntp_adjtime(&ntv) == TIME_ERROR) {
|
---|
2619 | if (!(ntv.status & STA_PPSSIGNAL))
|
---|
2620 | report_event(EVNT_KERN, NULL,
|
---|
2621 | "PPS no signal");
|
---|
2622 | }
|
---|
2623 | pll_status = ntv.status;
|
---|
2624 | #ifdef STA_NANO
|
---|
2625 | clock_offset = ntv.offset / 1e9;
|
---|
2626 | #else /* STA_NANO */
|
---|
2627 | clock_offset = ntv.offset / 1e6;
|
---|
2628 | #endif /* STA_NANO */
|
---|
2629 | clock_frequency = FREQTOD(ntv.freq);
|
---|
2630 |
|
---|
2631 | /*
|
---|
2632 | * If the kernel PPS is lit, monitor its performance.
|
---|
2633 | */
|
---|
2634 | if (ntv.status & STA_PPSTIME) {
|
---|
2635 | #ifdef STA_NANO
|
---|
2636 | clock_jitter = ntv.jitter / 1e9;
|
---|
2637 | #else /* STA_NANO */
|
---|
2638 | clock_jitter = ntv.jitter / 1e6;
|
---|
2639 | #endif /* STA_NANO */
|
---|
2640 | }
|
---|
2641 |
|
---|
2642 | #if defined(STA_NANO) && NTP_API == 4
|
---|
2643 | /*
|
---|
2644 | * If the TAI changes, update the kernel TAI.
|
---|
2645 | */
|
---|
2646 | if (loop_tai != sys_tai) {
|
---|
2647 | loop_tai = sys_tai;
|
---|
2648 | ntv.modes = MOD_TAI;
|
---|
2649 | ntv.constant = sys_tai;
|
---|
2650 | ntp_adjtime(&ntv);
|
---|
2651 | }
|
---|
2652 | #endif /* STA_NANO */
|
---|
2653 | }
|
---|
2654 | #endif /* KERNEL_PLL */
|
---|
2655 | #endif
|
---|