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sources: add trust option

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Assume time from a source that is specified with the trust option is
always true.  It can't be rejected as falseticker in the source
selection if sources that are specified without this option don't agree
with it.
This commit is contained in:
Miroslav Lichvar
2016-01-07 11:12:55 +01:00
parent fa15fb3d53
commit 936f5cb0f1
8 changed files with 49 additions and 14 deletions
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36
sources.c
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@@ -603,7 +603,8 @@ SRC_SelectSource(SRC_Instance updated_inst)
struct timeval now, ref_time;
int i, j, j1, j2, index, sel_prefer, n_endpoints, n_sel_sources;
int n_badstats_sources, max_sel_reach, max_badstat_reach;
int depth, best_depth, combined, stratum, min_stratum, max_score_index;
int depth, best_depth, trust_depth, best_trust_depth;
int combined, stratum, min_stratum, max_score_index;
double src_offset, src_offset_sd, src_frequency, src_skew;
double src_root_delay, src_root_dispersion;
double best_lo, best_hi, distance, sel_src_distance, max_score;
@@ -751,8 +752,12 @@ SRC_SelectSource(SRC_Instance updated_inst)
The first case is just bad luck - we need extra sources to
detect the falseticker, so just make an arbitrary choice based
on stratum & stability etc.
Intervals from sources specified with the trust option have higher
priority in the search.
*/
trust_depth = best_trust_depth = 0;
depth = best_depth = 0;
best_lo = best_hi = 0.0;
@@ -760,14 +765,20 @@ SRC_SelectSource(SRC_Instance updated_inst)
switch (sort_list[i].tag) {
case LOW:
depth++;
if (depth > best_depth) {
if (sources[sort_list[i].index]->sel_options & SRC_SELECT_TRUST)
trust_depth++;
if (trust_depth > best_trust_depth ||
(trust_depth == best_trust_depth && depth > best_depth)) {
best_trust_depth = trust_depth;
best_depth = depth;
best_lo = sort_list[i].offset;
}
break;
case HIGH:
if (depth == best_depth)
if (trust_depth == best_trust_depth && depth == best_depth)
best_hi = sort_list[i].offset;
if (sources[sort_list[i].index]->sel_options & SRC_SELECT_TRUST)
trust_depth--;
depth--;
break;
default:
@@ -775,9 +786,9 @@ SRC_SelectSource(SRC_Instance updated_inst)
}
}
if (best_depth <= n_sel_sources / 2) {
/* Could not even get half the reachable sources to agree -
clearly we can't synchronise. */
if (best_depth <= n_sel_sources / 2 && !best_trust_depth) {
/* Could not even get half the reachable sources to agree and there
are no trusted sources - clearly we can't synchronise */
if (selected_source_index != INVALID_SOURCE) {
log_selection_message("Can't synchronise: no majority", NULL);
@@ -798,14 +809,17 @@ SRC_SelectSource(SRC_Instance updated_inst)
n_sel_sources = 0;
for (i = 0; i < n_sources; i++) {
/* This should be the same condition to get into the endpoint
list */
if (sources[i]->status != SRC_OK)
continue;
/* This should be the same condition to get into the endpoint
list */
/* Check if source's interval contains the best interval, or
is wholly contained within it */
if ((sources[i]->sel_info.lo_limit <= best_lo &&
/* Check if source's interval contains the best interval, or is wholly
contained within it. If there are any trusted sources the first
condition is applied only to them to not allow non-trusted sources to
move the final offset outside the interval. */
if (((!best_trust_depth || sources[i]->sel_options & SRC_SELECT_TRUST) &&
sources[i]->sel_info.lo_limit <= best_lo &&
sources[i]->sel_info.hi_limit >= best_hi) ||
(sources[i]->sel_info.lo_limit >= best_lo &&
sources[i]->sel_info.hi_limit <= best_hi)) {