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Diffstat (limited to 'sources.c')
| -rw-r--r-- | sources.c | 1392 |
1 files changed, 1392 insertions, 0 deletions
diff --git a/sources.c b/sources.c new file mode 100644 index 0000000..9ca937e --- /dev/null +++ b/sources.c @@ -0,0 +1,1392 @@ +/* + chronyd/chronyc - Programs for keeping computer clocks accurate. + + ********************************************************************** + * Copyright (C) Richard P. Curnow 1997-2003 + * Copyright (C) Miroslav Lichvar 2011-2016, 2018 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + ********************************************************************** + + ======================================================================= + + The routines in this file manage the complete pool of sources that + we might be synchronizing to. This includes NTP sources and others + (e.g. local reference clocks, eyeball + wristwatch etc). + + */ + +#include "config.h" + +#include "sysincl.h" + +#include "sources.h" +#include "sourcestats.h" +#include "memory.h" +#include "ntp.h" /* For NTP_Leap */ +#include "ntp_sources.h" +#include "local.h" +#include "reference.h" +#include "util.h" +#include "conf.h" +#include "logging.h" +#include "reports.h" +#include "nameserv.h" +#include "sched.h" +#include "regress.h" + +/* ================================================== */ +/* Flag indicating that we are initialised */ +static int initialised = 0; + +/* ================================================== */ +/* Structure used to hold info for selecting between sources */ +struct SelectInfo { + NTP_Leap leap; + int stratum; + int select_ok; + double std_dev; + double root_distance; + double lo_limit; + double hi_limit; + double last_sample_ago; +}; + +/* ================================================== */ +/* This enum contains the flag values that are used to label + each source */ +typedef enum { + SRC_OK, /* OK so far, not a final status! */ + SRC_UNSELECTABLE, /* Has noselect option set */ + SRC_BAD_STATS, /* Doesn't have valid stats data */ + SRC_BAD_DISTANCE, /* Has root distance longer than allowed maximum */ + SRC_JITTERY, /* Had std dev larger than allowed maximum */ + SRC_WAITS_STATS, /* Others have bad stats, selection postponed */ + SRC_STALE, /* Has older samples than others */ + SRC_ORPHAN, /* Has stratum equal or larger than orphan stratum */ + SRC_UNTRUSTED, /* Overlaps trusted sources */ + SRC_FALSETICKER, /* Doesn't agree with others */ + SRC_WAITS_SOURCES, /* Not enough sources, selection postponed */ + SRC_NONPREFERRED, /* Others have prefer option */ + SRC_WAITS_UPDATE, /* No updates, selection postponed */ + SRC_DISTANT, /* Others have shorter root distance */ + SRC_OUTLIER, /* Outlier in clustering (not used yet) */ + SRC_UNSELECTED, /* Used for synchronisation, not system peer */ + SRC_SELECTED, /* Used for synchronisation, selected as system peer */ +} SRC_Status; + +/* ================================================== */ +/* Define the instance structure used to hold information about each + source */ +struct SRC_Instance_Record { + SST_Stats stats; + int index; /* Index back into the array of source */ + uint32_t ref_id; /* The reference ID of this source + (i.e. from its IP address, NOT the + reference _it_ is sync'd to) */ + IPAddr *ip_addr; /* Its IP address if NTP source */ + + /* Flag indicating that the source is updating reachability */ + int active; + + /* Reachability register */ + int reachability; + + /* Number of set bits in the reachability register */ + int reachability_size; + + /* Updates since last reference update */ + int updates; + + /* Updates left before allowing combining */ + int distant; + + /* Flag indicating the status of the source */ + SRC_Status status; + + /* Type of the source */ + SRC_Type type; + + /* Options used when selecting sources */ + int sel_options; + + /* Score against currently selected source */ + double sel_score; + + struct SelectInfo sel_info; +}; + +/* ================================================== */ +/* Structure used to build the sort list for finding falsetickers */ +struct Sort_Element { + int index; + double offset; + enum { + LOW = -1, + HIGH = 1 + } tag; +}; + +/* ================================================== */ +/* Table of sources */ +static struct SRC_Instance_Record **sources; +static struct Sort_Element *sort_list; +static int *sel_sources; +static int n_sources; /* Number of sources currently in the table */ +static int max_n_sources; /* Capacity of the table */ + +#define INVALID_SOURCE (-1) +static int selected_source_index; /* Which source index is currently + selected (set to INVALID_SOURCE + if no current valid reference) */ + +/* Score needed to replace the currently selected source */ +#define SCORE_LIMIT 10.0 + +/* Number of updates needed to reset the distant status */ +#define DISTANT_PENALTY 32 + +static double max_distance; +static double max_jitter; +static double reselect_distance; +static double stratum_weight; +static double combine_limit; + +/* ================================================== */ +/* Forward prototype */ + +static void +slew_sources(struct timespec *raw, struct timespec *cooked, double dfreq, + double doffset, LCL_ChangeType change_type, void *anything); +static void +add_dispersion(double dispersion, void *anything); +static char * +source_to_string(SRC_Instance inst); + +/* ================================================== */ +/* Initialisation function */ +void SRC_Initialise(void) { + sources = NULL; + sort_list = NULL; + sel_sources = NULL; + n_sources = 0; + max_n_sources = 0; + selected_source_index = INVALID_SOURCE; + max_distance = CNF_GetMaxDistance(); + max_jitter = CNF_GetMaxJitter(); + reselect_distance = CNF_GetReselectDistance(); + stratum_weight = CNF_GetStratumWeight(); + combine_limit = CNF_GetCombineLimit(); + initialised = 1; + + LCL_AddParameterChangeHandler(slew_sources, NULL); + LCL_AddDispersionNotifyHandler(add_dispersion, NULL); +} + +/* ================================================== */ +/* Finalisation function */ +void SRC_Finalise(void) +{ + LCL_RemoveParameterChangeHandler(slew_sources, NULL); + LCL_RemoveDispersionNotifyHandler(add_dispersion, NULL); + + Free(sources); + Free(sort_list); + Free(sel_sources); + + initialised = 0; +} + +/* ================================================== */ +/* Function to create a new instance. This would be called by one of + the individual source-type instance creation routines. */ + +SRC_Instance SRC_CreateNewInstance(uint32_t ref_id, SRC_Type type, int sel_options, + IPAddr *addr, int min_samples, int max_samples, + double min_delay, double asymmetry) +{ + SRC_Instance result; + + assert(initialised); + + if (min_samples == SRC_DEFAULT_MINSAMPLES) + min_samples = CNF_GetMinSamples(); + if (max_samples == SRC_DEFAULT_MAXSAMPLES) + max_samples = CNF_GetMaxSamples(); + + result = MallocNew(struct SRC_Instance_Record); + result->stats = SST_CreateInstance(ref_id, addr, min_samples, max_samples, + min_delay, asymmetry); + + if (n_sources == max_n_sources) { + /* Reallocate memory */ + max_n_sources = max_n_sources > 0 ? 2 * max_n_sources : 4; + if (sources) { + sources = ReallocArray(struct SRC_Instance_Record *, max_n_sources, sources); + sort_list = ReallocArray(struct Sort_Element, 3*max_n_sources, sort_list); + sel_sources = ReallocArray(int, max_n_sources, sel_sources); + } else { + sources = MallocArray(struct SRC_Instance_Record *, max_n_sources); + sort_list = MallocArray(struct Sort_Element, 3*max_n_sources); + sel_sources = MallocArray(int, max_n_sources); + } + } + + sources[n_sources] = result; + + result->index = n_sources; + result->type = type; + result->sel_options = sel_options; + + SRC_SetRefid(result, ref_id, addr); + SRC_ResetInstance(result); + + n_sources++; + + return result; +} + +/* ================================================== */ +/* Function to get rid of a source when it is being unconfigured. + This may cause the current reference source to be reselected, if this + was the reference source or contributed significantly to a + falseticker decision. */ + +void SRC_DestroyInstance(SRC_Instance instance) +{ + int dead_index, i; + + assert(initialised); + + SST_DeleteInstance(instance->stats); + dead_index = instance->index; + for (i=dead_index; i<n_sources-1; i++) { + sources[i] = sources[i+1]; + sources[i]->index = i; + } + --n_sources; + Free(instance); + + /* If this was the previous reference source, we have to reselect! */ + if (selected_source_index == dead_index) + SRC_ReselectSource(); + else if (selected_source_index > dead_index) + --selected_source_index; +} + +/* ================================================== */ + +void +SRC_ResetInstance(SRC_Instance instance) +{ + instance->active = 0; + instance->updates = 0; + instance->reachability = 0; + instance->reachability_size = 0; + instance->distant = 0; + instance->status = SRC_BAD_STATS; + instance->sel_score = 1.0; + + SST_ResetInstance(instance->stats); +} + +/* ================================================== */ + +void +SRC_SetRefid(SRC_Instance instance, uint32_t ref_id, IPAddr *addr) +{ + instance->ref_id = ref_id; + instance->ip_addr = addr; + SST_SetRefid(instance->stats, ref_id, addr); +} + +/* ================================================== */ + +SST_Stats +SRC_GetSourcestats(SRC_Instance instance) +{ + assert(initialised); + return instance->stats; +} + +/* ================================================== */ + +/* This function is called by one of the source drivers when it has + a new sample that is to be accumulated. + + This function causes the frequency estimation to be re-run for the + designated source, and the clock selection procedure to be re-run + afterwards. + */ + +void +SRC_AccumulateSample(SRC_Instance inst, NTP_Sample *sample) +{ + + assert(initialised); + + DEBUG_LOG("ip=[%s] t=%s ofs=%f del=%f disp=%f str=%d", + source_to_string(inst), UTI_TimespecToString(&sample->time), -sample->offset, + sample->root_delay, sample->root_dispersion, sample->stratum); + + if (REF_IsLeapSecondClose()) { + LOG(LOGS_INFO, "Dropping sample around leap second"); + return; + } + + SST_AccumulateSample(inst->stats, sample); + SST_DoNewRegression(inst->stats); +} + +/* ================================================== */ + +void +SRC_SetActive(SRC_Instance inst) +{ + inst->active = 1; +} + +/* ================================================== */ + +void +SRC_UnsetActive(SRC_Instance inst) +{ + inst->active = 0; +} + +/* ================================================== */ + +static int +special_mode_end(void) +{ + int i; + + for (i = 0; i < n_sources; i++) { + /* No updates from inactive sources */ + if (!sources[i]->active) + continue; + + /* Don't expect more updates than from an offline iburst NTP source */ + if (sources[i]->reachability_size >= SOURCE_REACH_BITS - 1) + continue; + + /* Check if the source could still have enough samples to be selectable */ + if (SOURCE_REACH_BITS - 1 - sources[i]->reachability_size + + SST_Samples(sources[i]->stats) >= MIN_SAMPLES_FOR_REGRESS) + return 0; + } + + return 1; +} + +void +SRC_UpdateReachability(SRC_Instance inst, int reachable) +{ + inst->reachability <<= 1; + inst->reachability |= !!reachable; + inst->reachability %= 1U << SOURCE_REACH_BITS; + + if (inst->reachability_size < SOURCE_REACH_BITS) + inst->reachability_size++; + + if (!reachable && inst->index == selected_source_index) { + /* Try to select a better source */ + SRC_SelectSource(NULL); + } + + /* Check if special reference update mode failed */ + if (REF_GetMode() != REF_ModeNormal && special_mode_end()) { + REF_SetUnsynchronised(); + } + + /* Try to replace NTP sources that are unreachable, falsetickers, or + have root distance or jitter larger than the allowed maximums */ + if (inst->type == SRC_NTP && + ((!inst->reachability && inst->reachability_size == SOURCE_REACH_BITS) || + inst->status == SRC_BAD_DISTANCE || inst->status == SRC_JITTERY || + inst->status == SRC_FALSETICKER)) { + NSR_HandleBadSource(inst->ip_addr); + } +} + +/* ================================================== */ + +void +SRC_ResetReachability(SRC_Instance inst) +{ + inst->reachability = 0; + inst->reachability_size = 0; + SRC_UpdateReachability(inst, 0); +} + +/* ================================================== */ + +static void +log_selection_message(char *format, char *arg) +{ + if (REF_GetMode() != REF_ModeNormal) + return; + LOG(LOGS_INFO, format, arg); +} + +/* ================================================== */ + +static int +compare_sort_elements(const void *a, const void *b) +{ + const struct Sort_Element *u = (const struct Sort_Element *) a; + const struct Sort_Element *v = (const struct Sort_Element *) b; + + if (u->offset < v->offset) { + return -1; + } else if (u->offset > v->offset) { + return +1; + } else if (u->tag < v->tag) { + return -1; + } else if (u->tag > v->tag) { + return +1; + } else { + return 0; + } +} + +/* ================================================== */ + +static char * +source_to_string(SRC_Instance inst) +{ + switch (inst->type) { + case SRC_NTP: + return UTI_IPToString(inst->ip_addr); + case SRC_REFCLOCK: + return UTI_RefidToString(inst->ref_id); + default: + assert(0); + } + return NULL; +} + +/* ================================================== */ + +static void +mark_ok_sources(SRC_Status status) +{ + int i; + + for (i = 0; i < n_sources; i++) { + if (sources[i]->status != SRC_OK) + continue; + sources[i]->status = status; + } +} + +/* ================================================== */ + +static int +combine_sources(int n_sel_sources, struct timespec *ref_time, double *offset, + double *offset_sd, double *frequency, double *frequency_sd, double *skew) +{ + struct timespec src_ref_time; + double src_offset, src_offset_sd, src_frequency, src_frequency_sd, src_skew; + double src_root_delay, src_root_dispersion, sel_src_distance, elapsed; + double offset_weight, sum_offset_weight, sum_offset, sum2_offset_sd; + double frequency_weight, sum_frequency_weight, sum_frequency; + double inv_sum2_frequency_sd, inv_sum2_skew; + int i, index, combined; + + if (n_sel_sources == 1) + return 1; + + sum_offset_weight = sum_offset = sum2_offset_sd = 0.0; + sum_frequency_weight = sum_frequency = inv_sum2_frequency_sd = inv_sum2_skew = 0.0; + + sel_src_distance = sources[selected_source_index]->sel_info.root_distance; + if (sources[selected_source_index]->type == SRC_NTP) + sel_src_distance += reselect_distance; + + for (i = combined = 0; i < n_sel_sources; i++) { + index = sel_sources[i]; + SST_GetTrackingData(sources[index]->stats, &src_ref_time, + &src_offset, &src_offset_sd, + &src_frequency, &src_frequency_sd, &src_skew, + &src_root_delay, &src_root_dispersion); + + /* Don't include this source if its distance is longer than the distance of + the selected source multiplied by the limit, their estimated frequencies + are not close, or it was recently marked as distant */ + + if (index != selected_source_index && + (sources[index]->sel_info.root_distance > combine_limit * sel_src_distance || + fabs(*frequency - src_frequency) > + combine_limit * (*skew + src_skew + LCL_GetMaxClockError()))) { + /* Use a smaller penalty in first few updates */ + sources[index]->distant = sources[index]->reachability_size >= SOURCE_REACH_BITS ? + DISTANT_PENALTY : 1; + } else if (sources[index]->distant) { + sources[index]->distant--; + } + + if (sources[index]->distant) { + sources[index]->status = SRC_DISTANT; + continue; + } + + if (sources[index]->status == SRC_OK) + sources[index]->status = SRC_UNSELECTED; + + elapsed = UTI_DiffTimespecsToDouble(ref_time, &src_ref_time); + src_offset += elapsed * src_frequency; + src_offset_sd += elapsed * src_frequency_sd; + offset_weight = 1.0 / sources[index]->sel_info.root_distance; + frequency_weight = 1.0 / SQUARE(src_frequency_sd); + + DEBUG_LOG("combining index=%d oweight=%e offset=%e osd=%e fweight=%e freq=%e fsd=%e skew=%e", + index, offset_weight, src_offset, src_offset_sd, + frequency_weight, src_frequency, src_frequency_sd, src_skew); + + sum_offset_weight += offset_weight; + sum_offset += offset_weight * src_offset; + sum2_offset_sd += offset_weight * (SQUARE(src_offset_sd) + + SQUARE(src_offset - *offset)); + + sum_frequency_weight += frequency_weight; + sum_frequency += frequency_weight * src_frequency; + inv_sum2_frequency_sd += 1.0 / SQUARE(src_frequency_sd); + inv_sum2_skew += 1.0 / SQUARE(src_skew); + + combined++; + } + + assert(combined); + *offset = sum_offset / sum_offset_weight; + *offset_sd = sqrt(sum2_offset_sd / sum_offset_weight); + *frequency = sum_frequency / sum_frequency_weight; + *frequency_sd = 1.0 / sqrt(inv_sum2_frequency_sd); + *skew = 1.0 / sqrt(inv_sum2_skew); + + DEBUG_LOG("combined result offset=%e osd=%e freq=%e fsd=%e skew=%e", + *offset, *offset_sd, *frequency, *frequency_sd, *skew); + + return combined; +} + +/* ================================================== */ +/* This function selects the current reference from amongst the pool + of sources we are holding and updates the local reference */ + +void +SRC_SelectSource(SRC_Instance updated_inst) +{ + struct SelectInfo *si; + struct timespec now, ref_time; + int i, j, j1, j2, index, sel_prefer, n_endpoints, n_sel_sources, sel_req_source; + int n_badstats_sources, max_sel_reach, max_sel_reach_size, max_badstat_reach; + int depth, best_depth, trust_depth, best_trust_depth; + int combined, stratum, min_stratum, max_score_index; + int orphan_stratum, orphan_source, leap_votes, leap_ins, leap_del; + double src_offset, src_offset_sd, src_frequency, src_frequency_sd, src_skew; + double src_root_delay, src_root_dispersion; + double best_lo, best_hi, distance, sel_src_distance, max_score; + double first_sample_ago, max_reach_sample_ago; + NTP_Leap leap_status; + + if (updated_inst) + updated_inst->updates++; + + if (n_sources == 0) { + /* In this case, we clearly cannot synchronise to anything */ + if (selected_source_index != INVALID_SOURCE) { + log_selection_message("Can't synchronise: no sources", NULL); + selected_source_index = INVALID_SOURCE; + } + return; + } + + /* This is accurate enough and cheaper than calling LCL_ReadCookedTime */ + SCH_GetLastEventTime(&now, NULL, NULL); + + /* Step 1 - build intervals about each source */ + + n_endpoints = 0; + n_sel_sources = 0; + n_badstats_sources = 0; + sel_req_source = 0; + max_sel_reach = max_badstat_reach = 0; + max_sel_reach_size = 0; + max_reach_sample_ago = 0.0; + + for (i = 0; i < n_sources; i++) { + assert(sources[i]->status != SRC_OK); + + /* If some sources are specified with the require option, at least one + of them will have to be selectable in order to update the clock */ + if (sources[i]->sel_options & SRC_SELECT_REQUIRE) + sel_req_source = 1; + + /* Ignore sources which were added with the noselect option */ + if (sources[i]->sel_options & SRC_SELECT_NOSELECT) { + sources[i]->status = SRC_UNSELECTABLE; + continue; + } + + si = &sources[i]->sel_info; + SST_GetSelectionData(sources[i]->stats, &now, &si->stratum, &si->leap, + &si->lo_limit, &si->hi_limit, &si->root_distance, + &si->std_dev, &first_sample_ago, + &si->last_sample_ago, &si->select_ok); + + if (!si->select_ok) { + ++n_badstats_sources; + sources[i]->status = SRC_BAD_STATS; + if (max_badstat_reach < sources[i]->reachability) + max_badstat_reach = sources[i]->reachability; + continue; + } + + /* Include extra dispersion in the root distance of sources that don't + have new samples (the last sample is older than span of all samples) */ + if (first_sample_ago < 2.0 * si->last_sample_ago) { + double extra_disp = LCL_GetMaxClockError() * + (2.0 * si->last_sample_ago - first_sample_ago); + si->root_distance += extra_disp; + si->lo_limit -= extra_disp; + si->hi_limit += extra_disp; + } + + /* Require the root distance to be below the allowed maximum */ + if (si->root_distance > max_distance) { + sources[i]->status = SRC_BAD_DISTANCE; + continue; + } + + /* And the same applies for the estimated standard deviation */ + if (si->std_dev > max_jitter) { + sources[i]->status = SRC_JITTERY; + continue; + } + + sources[i]->status = SRC_OK; /* For now */ + + if (sources[i]->reachability && max_reach_sample_ago < first_sample_ago) + max_reach_sample_ago = first_sample_ago; + + if (max_sel_reach < sources[i]->reachability) + max_sel_reach = sources[i]->reachability; + + if (max_sel_reach_size < sources[i]->reachability_size) + max_sel_reach_size = sources[i]->reachability_size; + } + + orphan_stratum = REF_GetOrphanStratum(); + orphan_source = INVALID_SOURCE; + + for (i = 0; i < n_sources; i++) { + if (sources[i]->status != SRC_OK) + continue; + + si = &sources[i]->sel_info; + + /* Reachability is not a requirement for selection. An unreachable source + can still be selected if its newest sample is not older than the oldest + sample from reachable sources. */ + if (!sources[i]->reachability && max_reach_sample_ago < si->last_sample_ago) { + sources[i]->status = SRC_STALE; + continue; + } + + /* When the local reference is configured with the orphan option, NTP + sources that have stratum equal to the configured local stratum are + considered to be orphans (i.e. serving local time while not being + synchronised with real time) and are excluded from the normal source + selection. Sources with stratum larger than the local stratum are + considered to be directly on indirectly synchronised to an orphan and + are always ignored. + + If no selectable source is available and all orphan sources have + reference IDs larger than the local ID, no source will be selected and + the local reference mode will be activated at some point, i.e. this host + will become an orphan. Otherwise, the orphan source with the smallest + reference ID will be selected. This ensures a group of servers polling + each other (with the same orphan configuration) which have no external + source can settle down to a state where only one server is serving its + local unsychronised time and others are synchronised to it. */ + + if (si->stratum >= orphan_stratum && sources[i]->type == SRC_NTP) { + sources[i]->status = SRC_ORPHAN; + + if (si->stratum == orphan_stratum && sources[i]->reachability && + (orphan_source == INVALID_SOURCE || + sources[i]->ref_id < sources[orphan_source]->ref_id)) + orphan_source = i; + + continue; + } + + ++n_sel_sources; + } + + /* If no selectable source is available, consider the orphan source */ + if (!n_sel_sources && orphan_source != INVALID_SOURCE) { + uint32_t local_ref_id = NSR_GetLocalRefid(sources[orphan_source]->ip_addr); + + if (!local_ref_id) { + LOG(LOGS_ERR, "Unknown local refid in orphan mode"); + } else if (sources[orphan_source]->ref_id < local_ref_id) { + sources[orphan_source]->status = SRC_OK; + n_sel_sources = 1; + DEBUG_LOG("selecting orphan refid=%"PRIx32, sources[orphan_source]->ref_id); + } + } + + for (i = 0; i < n_sources; i++) { + if (sources[i]->status != SRC_OK) + continue; + + si = &sources[i]->sel_info; + + j1 = n_endpoints; + j2 = j1 + 1; + + sort_list[j1].index = i; + sort_list[j1].offset = si->lo_limit; + sort_list[j1].tag = LOW; + + sort_list[j2].index = i; + sort_list[j2].offset = si->hi_limit; + sort_list[j2].tag = HIGH; + + n_endpoints += 2; + } + + DEBUG_LOG("badstat=%d sel=%d badstat_reach=%x sel_reach=%x size=%d max_reach_ago=%f", + n_badstats_sources, n_sel_sources, (unsigned int)max_badstat_reach, + (unsigned int)max_sel_reach, max_sel_reach_size, max_reach_sample_ago); + + /* Wait for the next call if we have no source selected and there is + a source with bad stats (has less than 3 samples) with reachability + equal to shifted maximum reachability of sources with valid stats. + This delays selecting source on start with servers using the same + polling interval until they all have valid stats. */ + if (n_badstats_sources && n_sel_sources && selected_source_index == INVALID_SOURCE && + max_sel_reach_size < SOURCE_REACH_BITS && max_sel_reach >> 1 == max_badstat_reach) { + mark_ok_sources(SRC_WAITS_STATS); + return; + } + + if (n_endpoints == 0) { + /* No sources provided valid endpoints */ + if (selected_source_index != INVALID_SOURCE) { + log_selection_message("Can't synchronise: no selectable sources", NULL); + selected_source_index = INVALID_SOURCE; + } + return; + } + + /* Now sort the endpoint list */ + qsort((void *) sort_list, n_endpoints, sizeof(struct Sort_Element), compare_sort_elements); + + /* Now search for the interval which is contained in the most + individual source intervals. Any source which overlaps this + will be a candidate. + + If we get a case like + + <-----------------------> + <--> + <--> + <===========> + + we will build the interval as shown with '=', whereas with an extra source we get + + <-----------------------> + <-------> + <--> + <--> + <==> + + 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; + + for (i = 0; i < n_endpoints; i++) { + switch (sort_list[i].tag) { + case LOW: + 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 (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: + assert(0); + } + } + + 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); + REF_SetUnsynchronised(); + selected_source_index = INVALID_SOURCE; + } + + /* .. and mark all sources as falsetickers (so they appear thus + on the outputs from the command client) */ + mark_ok_sources(SRC_FALSETICKER); + + return; + } + + /* We have our interval, now work out which source are in it, + i.e. build list of admissible sources. */ + + 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; + + /* 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)) { + + sel_sources[n_sel_sources++] = i; + + if (sources[i]->sel_options & SRC_SELECT_REQUIRE) + sel_req_source = 0; + } else if (sources[i]->sel_info.lo_limit <= best_lo && + sources[i]->sel_info.hi_limit >= best_hi) { + sources[i]->status = SRC_UNTRUSTED; + } else { + sources[i]->status = SRC_FALSETICKER; + } + } + + if (!n_sel_sources || sel_req_source || n_sel_sources < CNF_GetMinSources()) { + if (selected_source_index != INVALID_SOURCE) { + log_selection_message("Can't synchronise: %s selectable sources", + !n_sel_sources ? "no" : + sel_req_source ? "no required source in" : "not enough"); + selected_source_index = INVALID_SOURCE; + } + mark_ok_sources(SRC_WAITS_SOURCES); + return; + } + + /* Accept leap second status if more than half of selectable (and trusted + if there are any) sources agree */ + for (i = leap_ins = leap_del = leap_votes = 0; i < n_sel_sources; i++) { + index = sel_sources[i]; + if (best_trust_depth && !(sources[index]->sel_options & SRC_SELECT_TRUST)) + continue; + leap_votes++; + if (sources[index]->sel_info.leap == LEAP_InsertSecond) + leap_ins++; + else if (sources[index]->sel_info.leap == LEAP_DeleteSecond) + leap_del++; + } + + if (leap_ins > leap_votes / 2) + leap_status = LEAP_InsertSecond; + else if (leap_del > leap_votes / 2) + leap_status = LEAP_DeleteSecond; + else + leap_status = LEAP_Normal; + + /* If there are any sources with prefer option, reduce the list again + only to the preferred sources */ + for (i = 0; i < n_sel_sources; i++) { + if (sources[sel_sources[i]]->sel_options & SRC_SELECT_PREFER) + break; + } + if (i < n_sel_sources) { + for (i = j = 0; i < n_sel_sources; i++) { + if (!(sources[sel_sources[i]]->sel_options & SRC_SELECT_PREFER)) + sources[sel_sources[i]]->status = SRC_NONPREFERRED; + else + sel_sources[j++] = sel_sources[i]; + } + assert(j > 0); + n_sel_sources = j; + sel_prefer = 1; + } else { + sel_prefer = 0; + } + + /* Find minimum stratum */ + + index = sel_sources[0]; + min_stratum = sources[index]->sel_info.stratum; + for (i = 1; i < n_sel_sources; i++) { + index = sel_sources[i]; + stratum = sources[index]->sel_info.stratum; + if (stratum < min_stratum) + min_stratum = stratum; + } + + /* Update scores and find the source with maximum score */ + + max_score_index = INVALID_SOURCE; + max_score = 0.0; + sel_src_distance = 0.0; + + if (selected_source_index != INVALID_SOURCE) + sel_src_distance = sources[selected_source_index]->sel_info.root_distance + + (sources[selected_source_index]->sel_info.stratum - min_stratum) * stratum_weight; + + for (i = 0; i < n_sources; i++) { + /* Reset score for non-selectable sources */ + if (sources[i]->status != SRC_OK || + (sel_prefer && !(sources[i]->sel_options & SRC_SELECT_PREFER))) { + sources[i]->sel_score = 1.0; + sources[i]->distant = DISTANT_PENALTY; + continue; + } + + distance = sources[i]->sel_info.root_distance + + (sources[i]->sel_info.stratum - min_stratum) * stratum_weight; + if (sources[i]->type == SRC_NTP) + distance += reselect_distance; + + if (selected_source_index != INVALID_SOURCE) { + /* Update score, but only for source pairs where one source + has a new sample */ + if (sources[i] == updated_inst || + sources[selected_source_index] == updated_inst) { + + sources[i]->sel_score *= sel_src_distance / distance; + + if (sources[i]->sel_score < 1.0) + sources[i]->sel_score = 1.0; + } + } else { + /* When there is no selected source yet, assign scores so that the + source with minimum distance will have maximum score. The scores + will be reset when the source is selected later in this function. */ + sources[i]->sel_score = 1.0 / distance; + } + + DEBUG_LOG("select score=%f refid=%"PRIx32" match_refid=%"PRIx32" status=%u dist=%f", + sources[i]->sel_score, sources[i]->ref_id, + updated_inst ? updated_inst->ref_id : 0, + sources[i]->status, distance); + + if (max_score < sources[i]->sel_score) { + max_score = sources[i]->sel_score; + max_score_index = i; + } + } + + assert(max_score_index != INVALID_SOURCE); + + /* Is the current source still a survivor and no other source has reached + the score limit? */ + if (selected_source_index == INVALID_SOURCE || + sources[selected_source_index]->status != SRC_OK || + (max_score_index != selected_source_index && max_score > SCORE_LIMIT)) { + + /* Before selecting the new synchronisation source wait until the reference + can be updated */ + if (sources[max_score_index]->updates == 0) { + selected_source_index = INVALID_SOURCE; + mark_ok_sources(SRC_WAITS_UPDATE); + DEBUG_LOG("best source has no updates"); + return; + } + + selected_source_index = max_score_index; + log_selection_message("Selected source %s", + source_to_string(sources[selected_source_index])); + + /* New source has been selected, reset all scores */ + for (i = 0; i < n_sources; i++) { + sources[i]->sel_score = 1.0; + sources[i]->distant = 0; + } + } + + sources[selected_source_index]->status = SRC_SELECTED; + + /* Don't update reference when the selected source has no new samples */ + + if (sources[selected_source_index]->updates == 0) { + /* Mark the remaining sources as last combine_sources() call */ + + for (i = 0; i < n_sel_sources; i++) { + index = sel_sources[i]; + if (sources[index]->status == SRC_OK) + sources[index]->status = sources[index]->distant ? + SRC_DISTANT : SRC_UNSELECTED; + } + return; + } + + for (i = 0; i < n_sources; i++) + sources[i]->updates = 0; + + /* Now just use the statistics of the selected source combined with + the other selectable sources for trimming the local clock */ + + SST_GetTrackingData(sources[selected_source_index]->stats, &ref_time, + &src_offset, &src_offset_sd, + &src_frequency, &src_frequency_sd, &src_skew, + &src_root_delay, &src_root_dispersion); + + combined = combine_sources(n_sel_sources, &ref_time, &src_offset, &src_offset_sd, + &src_frequency, &src_frequency_sd, &src_skew); + + REF_SetReference(sources[selected_source_index]->sel_info.stratum, + leap_status, combined, + sources[selected_source_index]->ref_id, + sources[selected_source_index]->ip_addr, + &ref_time, src_offset, src_offset_sd, + src_frequency, src_frequency_sd, src_skew, + src_root_delay, src_root_dispersion); +} + +/* ================================================== */ +/* Force reselecting the best source */ + +void +SRC_ReselectSource(void) +{ + selected_source_index = INVALID_SOURCE; + SRC_SelectSource(NULL); +} + +/* ================================================== */ + +void +SRC_SetReselectDistance(double distance) +{ + if (reselect_distance != distance) { + reselect_distance = distance; + LOG(LOGS_INFO, "New reselect distance %f", distance); + } +} + +/* ================================================== */ +/* This routine is registered as a callback with the local clock + module, to be called whenever the local clock changes frequency or + is slewed. It runs through all the existing source statistics, and + adjusts them to make them look as though they were sampled under + the new regime. */ + +static void +slew_sources(struct timespec *raw, struct timespec *cooked, double dfreq, + double doffset, LCL_ChangeType change_type, void *anything) +{ + int i; + + for (i=0; i<n_sources; i++) { + if (change_type == LCL_ChangeUnknownStep) { + SST_ResetInstance(sources[i]->stats); + } else { + SST_SlewSamples(sources[i]->stats, cooked, dfreq, doffset); + } + } + + if (change_type == LCL_ChangeUnknownStep) { + /* After resetting no source is selectable, set reference unsynchronised */ + SRC_SelectSource(NULL); + } +} + +/* ================================================== */ +/* This routine is called when an indeterminate offset is introduced + into the local time. */ + +static void +add_dispersion(double dispersion, void *anything) +{ + int i; + + for (i = 0; i < n_sources; i++) { + SST_AddDispersion(sources[i]->stats, dispersion); + } +} + +/* ================================================== */ + +static +FILE *open_dumpfile(SRC_Instance inst, const char *mode) +{ + FILE *f; + char filename[1024], *dumpdir; + + dumpdir = CNF_GetDumpDir(); + if (dumpdir[0] == '\0') { + LOG(LOGS_WARN, "dumpdir not specified"); + return NULL; + } + + /* Include IP address in the name for NTP sources, or reference ID in hex */ + if ((inst->type == SRC_NTP && + snprintf(filename, sizeof (filename), "%s/%s.dat", dumpdir, + source_to_string(inst)) >= sizeof (filename)) || + (inst->type != SRC_NTP && + snprintf(filename, sizeof (filename), "%s/refid:%08"PRIx32".dat", + dumpdir, inst->ref_id) >= sizeof (filename))) { + LOG(LOGS_WARN, "dumpdir too long"); + return NULL; + } + + f = fopen(filename, mode); + if (!f && mode[0] != 'r') + LOG(LOGS_WARN, "Could not open dump file for %s", + source_to_string(inst)); + + return f; +} + +/* ================================================== */ +/* This is called to dump out the source measurement registers */ + +void +SRC_DumpSources(void) +{ + FILE *out; + int i; + + for (i = 0; i < n_sources; i++) { + out = open_dumpfile(sources[i], "w"); + if (!out) + continue; + SST_SaveToFile(sources[i]->stats, out); + fclose(out); + } +} + +/* ================================================== */ + +void +SRC_ReloadSources(void) +{ + FILE *in; + int i; + + for (i = 0; i < n_sources; i++) { + in = open_dumpfile(sources[i], "r"); + if (!in) + continue; + if (!SST_LoadFromFile(sources[i]->stats, in)) + LOG(LOGS_WARN, "Could not load dump file for %s", + source_to_string(sources[i])); + else + LOG(LOGS_INFO, "Loaded dump file for %s", + source_to_string(sources[i])); + fclose(in); + } +} + +/* ================================================== */ + +void +SRC_RemoveDumpFiles(void) +{ + char pattern[1024], name[64], *dumpdir, *s; + IPAddr ip_addr; + glob_t gl; + size_t i; + + dumpdir = CNF_GetDumpDir(); + if (dumpdir[0] == '\0' || + snprintf(pattern, sizeof (pattern), "%s/*.dat", dumpdir) >= sizeof (pattern)) + return; + + if (glob(pattern, 0, NULL, &gl)) + return; + + for (i = 0; i < gl.gl_pathc; i++) { + s = strrchr(gl.gl_pathv[i], '/'); + if (!s || snprintf(name, sizeof (name), "%s", s + 1) >= sizeof (name)) + continue; + + /* Remove .dat extension */ + if (strlen(name) < 4) + continue; + name[strlen(name) - 4] = '\0'; + + /* Check if it looks like name of an actual dump file */ + if (strncmp(name, "refid:", 6) && !UTI_StringToIP(name, &ip_addr)) + continue; + + DEBUG_LOG("Removing %s", gl.gl_pathv[i]); + unlink(gl.gl_pathv[i]); + } + + globfree(&gl); +} + +/* ================================================== */ + +int +SRC_IsSyncPeer(SRC_Instance inst) +{ + if (inst->index == selected_source_index) { + return 1; + } else { + return 0; + } + +} + +/* ================================================== */ + +int +SRC_IsReachable(SRC_Instance inst) +{ + return inst->reachability != 0; +} + +/* ================================================== */ + +int +SRC_ReadNumberOfSources(void) +{ + return n_sources; +} + +/* ================================================== */ + +int +SRC_ActiveSources(void) +{ + int i, r; + + for (i = r = 0; i < n_sources; i++) + if (sources[i]->active) + r++; + + return r; +} + +/* ================================================== */ + +int +SRC_ReportSource(int index, RPT_SourceReport *report, struct timespec *now) +{ + SRC_Instance src; + if ((index >= n_sources) || (index < 0)) { + return 0; + } else { + src = sources[index]; + + if (src->ip_addr) + report->ip_addr = *src->ip_addr; + else { + /* Use refid as an address */ + report->ip_addr.addr.in4 = src->ref_id; + report->ip_addr.family = IPADDR_INET4; + } + + switch (src->status) { + case SRC_FALSETICKER: + report->state = RPT_FALSETICKER; + break; + case SRC_JITTERY: + report->state = RPT_JITTERY; + break; + case SRC_UNTRUSTED: + case SRC_WAITS_SOURCES: + case SRC_NONPREFERRED: + case SRC_WAITS_UPDATE: + case SRC_DISTANT: + case SRC_OUTLIER: + report->state = RPT_OUTLIER; + break; + case SRC_UNSELECTED: + report->state = RPT_CANDIDATE; + break; + case SRC_SELECTED: + report->state = RPT_SYNC; + break; + default: + report->state = RPT_UNREACH; + break; + } + + report->sel_options = src->sel_options; + report->reachability = src->reachability; + + /* Call stats module to fill out estimates */ + SST_DoSourceReport(src->stats, report, now); + + return 1; + } + +} + +/* ================================================== */ + +int +SRC_ReportSourcestats(int index, RPT_SourcestatsReport *report, struct timespec *now) +{ + SRC_Instance src; + + if ((index >= n_sources) || (index < 0)) { + return 0; + } else { + src = sources[index]; + report->ref_id = src->ref_id; + if (src->ip_addr) + report->ip_addr = *src->ip_addr; + else + report->ip_addr.family = IPADDR_UNSPEC; + SST_DoSourcestatsReport(src->stats, report, now); + return 1; + } +} + +/* ================================================== */ + +SRC_Type +SRC_GetType(int index) +{ + if ((index >= n_sources) || (index < 0)) + return -1; + return sources[index]->type; +} + +/* ================================================== */ |