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Add test for ratio of increase in delay to stddev

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Require that the ratio of the increase in delay from the minimum one in
the stats data register to the standard deviation of the offsets in the
register is less than maxdelaydevratio or the difference between
measured offset and predicted offset is larger than the increase in
delay. In the allowed delay increase is included also skew and maximum
clock frequency error.

maxdelaydevratio is 10.0 by default.
This commit is contained in:
Miroslav Lichvar
2010-12-03 18:35:33 +01:00
parent feb8811f37
commit b977c95be4
12 changed files with 112 additions and 9 deletions
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25
ntp_core.c
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@@ -119,6 +119,8 @@ struct NCR_Instance_Record {
min_delay_in_register that we can
tolerate. */
double max_delay_dev_ratio; /* Maximum ratio of increase in delay / stddev */
int do_auth; /* Flag indicating whether we
authenticate packets we send to
this machine (if it's serving us or
@@ -213,7 +215,7 @@ void
NCR_Initialise(void)
{
logfileid = CNF_GetLogMeasurements() ? LOG_FileOpen("measurements",
" Date (UTC) Time IP Address L St 1234 ab 5678 LP RP Score Offset Peer del. Peer disp. Root del. Root disp.")
" Date (UTC) Time IP Address L St 1234 abc 5678 LP RP Score Offset Peer del. Peer disp. Root del. Root disp.")
: -1;
access_auth_table = ADF_CreateTable();
@@ -284,6 +286,7 @@ NCR_GetInstance(NTP_Remote_Address *remote_addr, NTP_Source_Type type, SourcePar
result->max_delay = params->max_delay;
result->max_delay_ratio = params->max_delay_ratio;
result->max_delay_dev_ratio = params->max_delay_dev_ratio;
result->tx_count = 0;
@@ -777,7 +780,7 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
int test1, test2, test3, test4, test5, test6, test7, test8;
int test4a, test4b;
int test4a, test4b, test4c;
/* In the words of section 3.4.4 of RFC1305, valid_data means
that the NTP protocol association with the peer/server is
@@ -941,6 +944,18 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
test4b = 1; /* Success */
}
/* Test 4c (additional to RFC1305) requires that the ratio of the
increase in delay from the minimum one in the stats data register to
the standard deviation of the offsets in the register is less than an
administrator-defined value or the difference between measured offset
and predicted offset is larger than the increase in delay */
if (!SRC_IsGoodSample(inst->source, -theta, delta, inst->max_delay_dev_ratio,
LCL_GetMaxClockError(), &sample_time)) {
test4c = 0; /* Failed */
} else {
test4c = 1; /* Success */
}
/* Test 5 relates to authentication. */
if (inst->do_auth) {
if (do_auth) {
@@ -1011,7 +1026,7 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
valid_kod = test1 && test2 && test5;
valid_data = test1 && test2 && test3 && test4 && test4a && test4b;
valid_data = test1 && test2 && test3 && test4 && test4a && test4b && test4c;
valid_header = test5 && test6 && test7 && test8;
root_delay = pkt_root_delay + delta;
@@ -1240,13 +1255,13 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
/* Do measurement logging */
if (logfileid != -1) {
LOG_FileWrite(logfileid, "%s %-15s %1c %2d %1d%1d%1d%1d %1d%1d %1d%1d%1d%1d %2d %2d %4.2f %10.3e %10.3e %10.3e %10.3e %10.3e",
LOG_FileWrite(logfileid, "%s %-15s %1c %2d %1d%1d%1d%1d %1d%1d%1d %1d%1d%1d%1d %2d %2d %4.2f %10.3e %10.3e %10.3e %10.3e %10.3e",
UTI_TimeToLogForm(sample_time.tv_sec),
UTI_IPToString(&inst->remote_addr.ip_addr),
sync_stats[pkt_leap],
message->stratum,
test1, test2, test3, test4,
test4a, test4b,
test4a, test4b, test4c,
test5, test6, test7, test8,
inst->local_poll, inst->remote_poll,
inst->poll_score,