/* detects host flapping */
void check_for_host_flapping(host *hst, int update, int actual_check, int allow_flapstart_notification) {
int update_history = TRUE;
int is_flapping = FALSE;
register int x = 0;
register int y = 0;
int last_state_history_value = HOST_UP;
unsigned long wait_threshold = 0L;
double curved_changes = 0.0;
double curved_percent_change = 0.0;
time_t current_time = 0L;
double low_threshold = 0.0;
double high_threshold = 0.0;
double low_curve_value = 0.75;
double high_curve_value = 1.25;
log_debug_info(DEBUGL_FUNCTIONS, 0, "check_for_host_flapping()\n");
if (hst == NULL)
return;
log_debug_info(DEBUGL_FLAPPING, 1, "Checking host '%s' for flapping...\n", hst->name);
time(¤t_time);
/* period to wait for updating archived state info if we have no state change */
if (hst->total_services == 0)
wait_threshold = hst->notification_interval * interval_length;
else
wait_threshold = (hst->total_service_check_interval * interval_length) / hst->total_services;
update_history = update;
/* should we update state history for this state? */
if (update_history == TRUE) {
if (hst->current_state == HOST_UP && hst->flap_detection_on_up == FALSE)
update_history = FALSE;
if (hst->current_state == HOST_DOWN && hst->flap_detection_on_down == FALSE)
update_history = FALSE;
if (hst->current_state == HOST_UNREACHABLE && hst->flap_detection_on_unreachable == FALSE)
update_history = FALSE;
}
/* if we didn't have an actual check, only update if we've waited long enough */
if (update_history == TRUE && actual_check == FALSE && (current_time - hst->last_state_history_update) < wait_threshold) {
update_history = FALSE;
}
/* what thresholds should we use (global or host-specific)? */
low_threshold = (hst->low_flap_threshold <= 0.0) ? low_host_flap_threshold : hst->low_flap_threshold;
high_threshold = (hst->high_flap_threshold <= 0.0) ? high_host_flap_threshold : hst->high_flap_threshold;
/* record current host state */
if (update_history == TRUE) {
/* update the last record time */
hst->last_state_history_update = current_time;
/* record the current state in the state history */
hst->state_history[hst->state_history_index] = hst->current_state;
/* increment state history index to next available slot */
hst->state_history_index++;
if (hst->state_history_index >= MAX_STATE_HISTORY_ENTRIES)
hst->state_history_index = 0;
}
/* calculate overall changes in state */
for (x = 0, y = hst->state_history_index; x < MAX_STATE_HISTORY_ENTRIES; x++) {
if (x == 0) {
last_state_history_value = hst->state_history[y];
y++;
if (y >= MAX_STATE_HISTORY_ENTRIES)
y = 0;
continue;
}
if (last_state_history_value != hst->state_history[y])
curved_changes += (((double)(x - 1) * (high_curve_value - low_curve_value)) / ((double)(MAX_STATE_HISTORY_ENTRIES - 2))) + low_curve_value;
last_state_history_value = hst->state_history[y];
y++;
if (y >= MAX_STATE_HISTORY_ENTRIES)
y = 0;
}
/* calculate overall percent change in state */
curved_percent_change = (double)(((double)curved_changes * 100.0) / (double)(MAX_STATE_HISTORY_ENTRIES - 1));
hst->percent_state_change = curved_percent_change;
log_debug_info(DEBUGL_FLAPPING, 2, "LFT (low_threshold): %.2f, HFT (high_threshold): %.2f, CPC (curved_percent_change): %.2f, PSC (curved_percent_change): %.2f%%\n",
low_threshold, high_threshold, curved_percent_change, curved_percent_change);
/* don't do anything if we don't have flap detection enabled on a program-wide basis */
if (enable_flap_detection == FALSE)
return;
/* don't do anything if we don't have flap detection enabled for this host */
if (hst->flap_detection_enabled == FALSE)
return;
/* are we flapping, undecided, or what?... */
/* we're undecided, so don't change the current flap state */
if (curved_percent_change > low_threshold && curved_percent_change < high_threshold)
return;
/* we're below the lower bound, so we're not flapping */
else if (curved_percent_change <= low_threshold)
is_flapping = FALSE;
/* else we're above the upper bound, so we are flapping */
else if (curved_percent_change >= high_threshold)
is_flapping = TRUE;
log_debug_info(DEBUGL_FLAPPING, 1, "Host %s flapping (%.2f%% state change).\n", (is_flapping == TRUE) ? "is" : "is not", curved_percent_change);
/* did the host just start flapping? */
if (is_flapping == TRUE && hst->is_flapping == FALSE)
set_host_flap(hst, curved_percent_change, high_threshold, low_threshold, allow_flapstart_notification);
/* did the host just stop flapping? */
else if (is_flapping == FALSE && hst->is_flapping == TRUE)
clear_host_flap(hst, curved_percent_change, high_threshold, low_threshold);
return;
}
/* detects host flapping */
void check_for_host_flapping(host *hst, int update, int actual_check, int allow_flapstart_notification)
{
int is_flapping = FALSE;
unsigned long wait_threshold = 0L;
time_t current_time = 0L;
double low_threshold = 0.0;
double high_threshold = 0.0;
log_debug_info(DEBUGL_FUNCTIONS, 0, "check_for_host_flapping()\n");
if (hst == NULL || !should_flap_detect(hst))
return;
log_debug_info(DEBUGL_FLAPPING, 1, "Checking host '%s' for flapping...\n", hst->name);
time(¤t_time);
/* period to wait for updating archived state info if we have no state change */
if (hst->total_services == 0)
wait_threshold = hst->notification_interval * interval_length;
else
wait_threshold = (hst->total_service_check_interval * interval_length) / hst->total_services;
/* update history on actual checks and when enough time has passed */
if (current_time - hst->last_state_history_update > (time_t)wait_threshold)
update = TRUE;
if (actual_check == TRUE)
update = TRUE;
/*
* return early if we shouldn't update state history, as flapping
* state won't change and we won't send notifications regardless
*/
if (!update)
return;
/* what thresholds should we use (global or host-specific)? */
low_threshold = (hst->low_flap_threshold <= 0.0) ? low_host_flap_threshold : hst->low_flap_threshold;
high_threshold = (hst->high_flap_threshold <= 0.0) ? high_host_flap_threshold : hst->high_flap_threshold;
/* update the last record time */
hst->last_state_history_update = current_time;
/* record the current state in the state history */
hst->state_history[hst->state_history_index] = hst->current_state;
/* increment state history index to next available slot */
hst->state_history_index++;
if (hst->state_history_index >= MAX_STATE_HISTORY_ENTRIES)
hst->state_history_index = 0;
hst->percent_state_change = flapping_pct(hst->state_history, hst->state_history_index,
MAX_STATE_HISTORY_ENTRIES);
log_debug_info(DEBUGL_FLAPPING, 2, "LFT=%.2f, HFT=%.2f, CPC=%.2f, PSC=%.2f%%\n", low_threshold, high_threshold, hst->percent_state_change, hst->percent_state_change);
/* bail early if flap detection is disabled */
if (enable_flap_detection == FALSE)
return;
if (hst->flap_detection_enabled == FALSE)
return;
/* we're undecided, so don't change the current flap state */
if (hst->percent_state_change > low_threshold && hst->percent_state_change < high_threshold)
return;
/* we're below the lower bound, so we're not flapping */
if (hst->percent_state_change <= low_threshold)
is_flapping = FALSE;
/* else we're above the upper bound, so we are flapping */
else if (hst->percent_state_change >= high_threshold)
is_flapping = TRUE;
log_debug_info(DEBUGL_FLAPPING, 1, "Host %s flapping (%.2f%% state change).\n", (is_flapping == TRUE) ? "is" : "is not", hst->percent_state_change);
/* did the host just start flapping? */
if (is_flapping == TRUE && hst->is_flapping == FALSE)
set_host_flap(hst, hst->percent_state_change, high_threshold, low_threshold, allow_flapstart_notification);
/* did the host just stop flapping? */
else if (is_flapping == FALSE && hst->is_flapping == TRUE)
clear_host_flap(hst, hst->percent_state_change, high_threshold, low_threshold);
}