reference: rework adjustment of reference timestamp

Instead of converting the reference timestamp to the NTP format and
back, add a negative double value to the timestamp directly. Move the
code to a separate function. This will allow the timestamp to stay
outside the compiled-in NTP era, which is useful for testing of the
cmdmon protocol.

diff --git a/reference.c b/reference.c
index 40b748230c3ec04b59c0cbaccfdc21ebb9967569..cdc61968097fdea433cb72d7d4e7a3cc163a1cec 100644 (file)
--- a/reference.c
+++ b/reference.c
@@ -959,6 +959,18 @@ get_clock_estimates(int manual,
 
 /* ================================================== */
 
+static void
+fuzz_ref_time(struct timespec *ts)
+{
+  uint32_t rnd;
+
+  /* Add a random value from interval [-1.0, 0.0] */
+  UTI_GetRandomBytes(&rnd, sizeof (rnd));
+  UTI_AddDoubleToTimespec(ts, -(double)rnd / (uint32_t)-1, ts);
+}
+
+/* ================================================== */
+
 void
 REF_SetReference(int stratum, NTP_Leap leap, int combined_sources,
                  uint32_t ref_id, IPAddr *ref_ip, struct timespec *ref_time,
@@ -970,7 +982,6 @@ REF_SetReference(int stratum, NTP_Leap leap, int combined_sources,
   double residual_frequency, local_abs_frequency;
   double elapsed, update_interval, correction_rate, orig_root_distance;
   struct timespec now, raw_now;
-  NTP_int64 ref_fuzz;
   int manual;
 
   assert(initialised);
@@ -1065,11 +1076,7 @@ REF_SetReference(int stratum, NTP_Leap leap, int combined_sources,
   /* Add a random error of up to one second to the reference time to make it
      less useful when disclosed to NTP and cmdmon clients for estimating
      receive timestamps in the interleaved symmetric NTP mode */
-  UTI_GetNtp64Fuzz(&ref_fuzz, 0);
-  UTI_TimespecToNtp64(&our_ref_time, &ref_fuzz, &ref_fuzz);
-  UTI_Ntp64ToTimespec(&ref_fuzz, &our_ref_time);
-  if (UTI_CompareTimespecs(&our_ref_time, ref_time) >= 0)
-    our_ref_time.tv_sec--;
+  fuzz_ref_time(&our_ref_time);
 
   local_abs_frequency = LCL_ReadAbsoluteFrequency();