local: reset daemon after unexpected time jump

Add a new change type and use it when an unexpected time jump is
detected in the scheduler to reset reference times, offset and slewing,
NCR instances (with their polling interval), synchronization status, and
drop all sourcestats, manual, refclock and RTC samples.

This should make the recovery more graceful if the estimated jump has a
large error (e.g. select didn't timeout, or after system suspend).

local.c

@@ -479,7 +479,7 @@ LCL_NotifyExternalTimeStep(struct timeval *raw, struct timeval *cooked,
     double offset, double dispersion)
 {
   /* Dispatch to all handlers */
-  invoke_parameter_change_handlers(raw, cooked, 0.0, offset, LCL_ChangeStep);
+  invoke_parameter_change_handlers(raw, cooked, 0.0, offset, LCL_ChangeUnknownStep);
 
   lcl_InvokeDispersionNotifyHandlers(dispersion);
 }

local.h

@@ -74,7 +74,8 @@ extern void LCL_GetOffsetCorrection(struct timeval *raw, double *correction, dou
 
 typedef enum {
   LCL_ChangeAdjust,
-  LCL_ChangeStep
+  LCL_ChangeStep,
+  LCL_ChangeUnknownStep
 } LCL_ChangeType;
 
 typedef void (*LCL_ParameterChangeHandler)

manual.c

@@ -221,6 +221,11 @@ slew_samples(struct timeval *raw,
 {
   double delta_time;
   int i;
+
+  if (change_type == LCL_ChangeUnknownStep) {
+    MNL_Reset();
+  }
+
   for (i=0; i<n_samples; i++) {
     UTI_AdjustTimeval(&samples[i].when, cooked, &samples[i].when, &delta_time,
         dfreq, doffset);

ntp_sources.c

@@ -491,9 +491,13 @@ slew_sources(struct timeval *raw,
           UTI_IPToString(&records[i].remote_addr->ip_addr), dfreq, doffset);
 #endif
 
+      if (change_type == LCL_ChangeUnknownStep) {
+        NCR_ResetInstance(records[i].data);
+      } else {
         NCR_SlewTimes(records[i].data, cooked, dfreq, doffset);
       }
     }
+  }
 
 }
 

refclock.c

@@ -581,9 +581,13 @@ slew_samples(struct timeval *raw, struct timeval *cooked, double dfreq,
 {
   int i;
 
-  for (i = 0; i < n_sources; i++)
+  for (i = 0; i < n_sources; i++) {
+    if (change_type == LCL_ChangeUnknownStep)
+      filter_reset(&refclocks[i].filter);
+    else
       filter_slew_samples(&refclocks[i].filter, cooked, dfreq, doffset);
   }
+}
 
 static void
 add_dispersion(double dispersion, void *anything)

reference.c

@@ -147,7 +147,10 @@ handle_slew(struct timeval *raw,
             LCL_ChangeType change_type,
             void *anything)
 {
-  if (change_type == LCL_ChangeStep) {
+  if (change_type == LCL_ChangeUnknownStep) {
+    last_ref_update.tv_sec = 0;
+    last_ref_update.tv_usec = 0;
+  } else if (change_type == LCL_ChangeStep) {
     UTI_AddDoubleToTimeval(&last_ref_update, -doffset, &last_ref_update);
   }
 }

rtc_linux.c

@@ -273,6 +273,11 @@ slew_samples
   double delta_time;
   double old_seconds_fast, old_gain_rate;
 
+  if (change_type == LCL_ChangeUnknownStep) {
+    /* Drop all samples. */
+    n_samples = 0;
+  }
+
   for (i=0; i<n_samples; i++) {
     UTI_AdjustTimeval(system_times + i, cooked, system_times + i, &delta_time,
         dfreq, doffset);

sources.c

@@ -1093,9 +1093,17 @@ slew_sources(struct timeval *raw,
   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);
+  }
 }
 
 /* ================================================== */

sys_generic.c

@@ -87,6 +87,7 @@ static double slew_error;
 /* ================================================== */
 
 static void handle_end_of_slew(void *anything);
+static void update_slew(void);
 
 /* ================================================== */
 /* Adjust slew_start on clock step */
@@ -95,9 +96,15 @@ static void
 handle_step(struct timeval *raw, struct timeval *cooked, double dfreq,
             double doffset, LCL_ChangeType change_type, void *anything)
 {
-  if (change_type == LCL_ChangeStep)
+  if (change_type == LCL_ChangeUnknownStep) {
+    /* Reset offset and slewing */
+    slew_start = *raw;
+    offset_register = 0.0;
+    update_slew();
+  } else if (change_type == LCL_ChangeStep) {
     UTI_AddDoubleToTimeval(&slew_start, -doffset, &slew_start);
   }
+}
 
 /* ================================================== */
 /* End currently running slew and start a new one */

test/simulation/005-externalstep

@@ -4,8 +4,8 @@
 
 test_start "external time step"
 
-min_sync_time=1300
-max_sync_time=1500
+min_sync_time=1500
+max_sync_time=1550
 
 for step in -1e2 1e2; do
 	# Make one step in 150th second