From 70928dba5250406c4cbd56af66caf6f03d30c449 Mon Sep 17 00:00:00 2001
From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Mon, 7 Apr 2014 16:15:40 +0200
Subject: [PATCH] ntp: set maximum number of iburst samples to size of reach
 register

Explicitly set the number of iburst samples to the size of the register
to make sure there are at least 7 reachability updates and the
initstepslew mode can be ended.
---
 ntp_core.c |  6 +++++-
 sources.c  | 11 ++++-------
 sources.h  |  3 +++
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/ntp_core.c b/ntp_core.c
index 719172b..3d55d72 100644
--- a/ntp_core.c
+++ b/ntp_core.c
@@ -186,6 +186,10 @@ struct NCR_Instance_Record {
    a reply to the previous probe */
 #define BURST_TIMEOUT 8.0
 
+/* Number of samples in initial burst */
+#define IBURST_GOOD_SAMPLES 4
+#define IBURST_TOTAL_SAMPLES SOURCE_REACH_BITS
+
 /* Time to wait after sending echo to 'warm up' link */
 #define WARM_UP_DELAY 4.0
 
@@ -345,7 +349,7 @@ NCR_GetInstance(NTP_Remote_Address *remote_addr, NTP_Source_Type type, SourcePar
   }
   
   if (params->iburst) {
-    NCR_InitiateSampleBurst(result, 4, 8);
+    NCR_InitiateSampleBurst(result, IBURST_GOOD_SAMPLES, IBURST_TOTAL_SAMPLES);
   }
 
   result->auto_offline = params->auto_offline;
diff --git a/sources.c b/sources.c
index 77245ca..364058a 100644
--- a/sources.c
+++ b/sources.c
@@ -135,9 +135,6 @@ static int selected_source_index; /* Which source index is currently
                                      selected (set to INVALID_SOURCE
                                      if no current valid reference) */
 
-/* Keep reachability status for last 8 samples */
-#define REACH_BITS 8
-
 /* Score needed to replace the currently selected source */
 #define SCORE_LIMIT 10.0
 
@@ -354,9 +351,9 @@ SRC_UpdateReachability(SRC_Instance inst, int reachable)
 {
   inst->reachability <<= 1;
   inst->reachability |= !!reachable;
-  inst->reachability &= ~(-1 << REACH_BITS);
+  inst->reachability &= ~(-1 << SOURCE_REACH_BITS);
 
-  if (inst->reachability_size < REACH_BITS)
+  if (inst->reachability_size < SOURCE_REACH_BITS)
       inst->reachability_size++;
 
   if (!reachable && inst->index == selected_source_index) {
@@ -366,7 +363,7 @@ SRC_UpdateReachability(SRC_Instance inst, int reachable)
 
   /* End special reference mode on last reachability update from iburst */
   if (REF_GetMode() != REF_ModeNormal &&
-      inst->reachability_size >= REACH_BITS - 1) {
+      inst->reachability_size >= SOURCE_REACH_BITS - 1) {
     REF_SetUnsynchronised();
   }
 }
@@ -458,7 +455,7 @@ combine_sources(int n_sel_sources, struct timeval *ref_time, double *offset,
          fabs(*frequency - src_frequency) >
            combine_limit * (*skew + src_skew + LCL_GetMaxClockError()))) {
       /* Use a smaller penalty in first few updates */
-      sources[index]->outlier = sources[index]->reachability_size >= REACH_BITS ?
+      sources[index]->outlier = sources[index]->reachability_size >= SOURCE_REACH_BITS ?
                                 OUTLIER_PENALTY : 1;
     } else if (sources[index]->outlier) {
       sources[index]->outlier--;
diff --git a/sources.h b/sources.h
index d06d25d..3037ee9 100644
--- a/sources.h
+++ b/sources.h
@@ -34,6 +34,9 @@
 #include "ntp.h"
 #include "reports.h"
 
+/* Size of the source reachability register */
+#define SOURCE_REACH_BITS 8
+
 /* This datatype is used to hold information about sources.  The
    instance must be passed when calling many of the interface
    functions */