From 936f5cb0f1146b8f00668422cbf931572e82337c Mon Sep 17 00:00:00 2001 From: Miroslav Lichvar Date: Thu, 7 Jan 2016 11:12:55 +0100 Subject: [PATCH] sources: add trust option 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. --- candm.h | 2 ++ chrony.texi.in | 9 +++++++++ client.c | 3 ++- cmdmon.c | 6 ++++-- cmdparse.c | 3 +++ conf.c | 3 +++ sources.c | 36 +++++++++++++++++++++++++----------- srcparams.h | 1 + 8 files changed, 49 insertions(+), 14 deletions(-) diff --git a/candm.h b/candm.h index a740aa2..5b7c8d2 100644 --- a/candm.h +++ b/candm.h @@ -243,6 +243,7 @@ typedef struct { #define REQ_ADDSRC_IBURST 0x4 #define REQ_ADDSRC_PREFER 0x8 #define REQ_ADDSRC_NOSELECT 0x10 +#define REQ_ADDSRC_TRUST 0x20 typedef struct { IPAddr ip_addr; @@ -478,6 +479,7 @@ typedef struct { #define RPY_SD_FLAG_NOSELECT 0x1 #define RPY_SD_FLAG_PREFER 0x2 +#define RPY_SD_FLAG_TRUST 0x4 typedef struct { IPAddr ip_addr; diff --git a/chrony.texi.in b/chrony.texi.in index 59caf74..73f9023 100644 --- a/chrony.texi.in +++ b/chrony.texi.in @@ -2720,6 +2720,10 @@ Prefer this source over sources without prefer option. @item noselect Never select this source. This is useful for monitoring or with sources which are not very accurate, but are locked with a PPS refclock. +@item trust +Assume time from this source is always true. It can't be rejected as a +falseticker in the source selection if sources that are specified without this +option don't agree with it. @item minsamples Set the minimum number of samples kept for this source. This overrides the @code{minsamples} directive (@pxref{minsamples directive}). @@ -3024,6 +3028,11 @@ Prefer this source over sources without prefer option. @item noselect Never select this source. This is particularly useful for monitoring. +@item trust +Assume time from this source is always true. It can't be rejected as a +falseticker in the source selection if sources that are specified without this +option don't agree with it. + @item minsamples Set the minimum number of samples kept for this source. This overrides the @code{minsamples} directive (@pxref{minsamples directive}). diff --git a/client.c b/client.c index d19ec84..aa7271a 100644 --- a/client.c +++ b/client.c @@ -1118,7 +1118,8 @@ process_cmd_add_server_or_peer(CMD_Request *msg, char *line) (data.params.auto_offline ? REQ_ADDSRC_AUTOOFFLINE : 0) | (data.params.iburst ? REQ_ADDSRC_IBURST : 0) | (data.params.sel_options & SRC_SELECT_PREFER ? REQ_ADDSRC_PREFER : 0) | - (data.params.sel_options & SRC_SELECT_NOSELECT ? REQ_ADDSRC_NOSELECT : 0)); + (data.params.sel_options & SRC_SELECT_NOSELECT ? REQ_ADDSRC_NOSELECT : 0) | + (data.params.sel_options & SRC_SELECT_TRUST ? REQ_ADDSRC_TRUST : 0)); result = 1; break; diff --git a/cmdmon.c b/cmdmon.c index bf22de9..ae2a10c 100644 --- a/cmdmon.c +++ b/cmdmon.c @@ -663,7 +663,8 @@ handle_source_data(CMD_Request *rx_message, CMD_Reply *tx_message) } tx_message->data.source_data.flags = htons((report.sel_options & SRC_SELECT_PREFER ? RPY_SD_FLAG_PREFER : 0) | - (report.sel_options & SRC_SELECT_NOSELECT ? RPY_SD_FLAG_NOSELECT : 0)); + (report.sel_options & SRC_SELECT_NOSELECT ? RPY_SD_FLAG_NOSELECT : 0) | + (report.sel_options & SRC_SELECT_TRUST ? RPY_SD_FLAG_TRUST : 0)); tx_message->data.source_data.reachability = htons(report.reachability); tx_message->data.source_data.since_sample = htonl(report.latest_meas_ago); tx_message->data.source_data.orig_latest_meas = UTI_FloatHostToNetwork(report.orig_latest_meas); @@ -758,7 +759,8 @@ handle_add_source(NTP_Source_Type type, CMD_Request *rx_message, CMD_Reply *tx_m params.iburst = ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_IBURST ? 1 : 0; params.sel_options = (ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_PREFER ? SRC_SELECT_PREFER : 0) | - (ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_NOSELECT ? SRC_SELECT_NOSELECT : 0); + (ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_NOSELECT ? SRC_SELECT_NOSELECT : 0) | + (ntohl(rx_message->data.ntp_source.flags) & REQ_ADDSRC_TRUST ? SRC_SELECT_TRUST : 0); params.max_delay = UTI_FloatNetworkToHost(rx_message->data.ntp_source.max_delay); params.max_delay_ratio = UTI_FloatNetworkToHost(rx_message->data.ntp_source.max_delay_ratio); diff --git a/cmdparse.c b/cmdparse.c index 51a9364..976e696 100644 --- a/cmdparse.c +++ b/cmdparse.c @@ -170,6 +170,9 @@ CPS_ParseNTPSourceAdd(char *line, CPS_NTP_Source *src) } else if (!strcasecmp(cmd, "prefer")) { src->params.sel_options |= SRC_SELECT_PREFER; + } else if (!strcasecmp(cmd, "trust")) { + src->params.sel_options |= SRC_SELECT_TRUST; + } else if (!strcasecmp(cmd, "version")) { if (sscanf(line, "%d%n", &src->params.version, &n) != 1) { result = CPS_BadVersion; diff --git a/conf.c b/conf.c index c556476..8260de6 100644 --- a/conf.c +++ b/conf.c @@ -743,6 +743,9 @@ parse_refclock(char *line) } else if (!strcasecmp(cmd, "prefer")) { n = 0; sel_options |= SRC_SELECT_PREFER; + } else if (!strcasecmp(cmd, "trust")) { + n = 0; + sel_options |= SRC_SELECT_TRUST; } else { other_parse_error("Invalid refclock option"); return; diff --git a/sources.c b/sources.c index c67cf51..2e48c5f 100644 --- a/sources.c +++ b/sources.c @@ -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)) { diff --git a/srcparams.h b/srcparams.h index 1e15af6..15fb6f2 100644 --- a/srcparams.h +++ b/srcparams.h @@ -66,5 +66,6 @@ typedef struct { /* Flags for source selection */ #define SRC_SELECT_NOSELECT 0x1 #define SRC_SELECT_PREFER 0x2 +#define SRC_SELECT_TRUST 0x4 #endif /* GOT_SRCPARAMS_H */