[FEATURE: #268] userspace/snmpd: improve reporting of offset between NTP and WR time

Add wrsSystemClockDriftUs (in microseconds) as int32. There is no need
to export this value as int64, with greater values of the offset
the exact information about the offset is not needed.

Signed-off-by: Adam Wujek <dev_public@wujek.eu>

userspace/rootfs_override/etc/init.d/system_clock_monitor

@@ -95,12 +95,17 @@ setCronConfig ()
 compareToThreshold () 
 {
 	local  __resultvar=$1
-	local  __c_offset=$2
+	# $(( )) to remove leading "+"
+	local  __c_offset=$(( $2 ))
 	local  __c_threshold=$3
 
 	if (( $__c_offset >= __c_threshold )) ; then
-		x=$(expr $__c_offset - $__c_threshold)
-		debug "System clock drift is exceedind the threshold by ${x} sec"
+		x=$(( $__c_offset - $__c_threshold ))
+		debug "X1System clock drift is exceeding the threshold by ${x} sec"
+		eval $__resultvar="1"
+	elif (( -$__c_offset >= __c_threshold )) ; then
+		x=$(( $__c_offset + $__c_threshold ))
+		debug "X2System clock drift is exceeding the threshold by ${x} sec"
 		eval $__resultvar="1"
 	else
 		debug "System clock drift is not exceeding the threshold"
@@ -109,27 +114,36 @@ compareToThreshold ()
 }
 
 #
-# Decode NTPD deamon output to get the offset in ms
+# Decode NTPD deamon output to get the offset in seconds.useconds
 #
 
-decodeOffsetMs () 
+decodeOffset ()
 {
 	local __resultvar=$1
 	local __str=$2
-	local __offset=$(echo $__str | sed -n 's/.* offset:[+-]\?\([0-9]*\).*/\1/p')
+	local __offset=$(echo $__str | sed -n 's/.* offset:\?\([+-][0-9]*\)\.\?\([0-9]*\) .*/\1.\2/p')
 	
 	if [[ -z "$__offset" ]] ; then
 		# Empty string
 		debug "Invalid Offset !!!"
 		debug "NTP msg=\"$__str\""
-		eval $__resultvar="-1"
-	else 
-		offset=$(expr $__offset + 0)
-		debug "NTP offset=$__offset ms" 
+		return 1
+	else
+		# Change the sign of the offset. ntpd returns a positive
+		# offset when the ntp time is ahead of the local time, which is
+		# counter-intuitive.
+		if [ "${__offset:0:1}" = "-" ]; then
+			__offset=+${__offset:1}
+		elif [ "${__offset:0:1}" = "+" ]; then
+			__offset=-${__offset:1}
+		fi
+		debug "NTP offset=$__offset s"
 		eval $__resultvar="'$__offset'"
+		return 0
 	fi 
 }
 
+
 #
 # Kill the NTPD daemon in background after few seconds
 #
@@ -171,9 +185,9 @@ read_ntp_server()
 		killNTPD 10
 		ntpRes=$($ntpTool  -n -w -q -d -p  $server 2>&1)
 		if [ -n "$ntpRes" ] ; then
-			decodeOffsetMs offset "$ntpRes"
-			if (( $offset >= 0 )) ; then
-				compareToThreshold alarmState $offset $ltThreshold
+			decodeOffset offset "$ntpRes"
+			if [ $? -eq 0 ] ; then
+				compareToThreshold alarmState ${offset%.*} $ltThreshold
 				if (( $alarmState == 1 )) ; then
 					# Exceeded Threshold  
 					writeMsg "exceeded_threshold" $systemClockMonitoringStatus

userspace/snmpd/WR-SWITCH-MIB.txt

@@ -30,6 +30,7 @@ wrSwitchMIB MODULE-IDENTITY
     DESCRIPTION
         "Updates for v6.1 WRS firmware release
         Added objects:
+         - wrsSystemClockDriftUs
          - wrsVersionFeatures
         "
 
@@ -731,6 +732,15 @@ wrsLeapSecSourceURL OBJECT-TYPE
         "Url to the leap second file"
     ::= { wrsCurrentTimeGroup 11 }
 
+wrsSystemClockDriftUs OBJECT-TYPE
+    SYNTAX         Integer32
+    MAX-ACCESS     read-only
+    STATUS         current
+    DESCRIPTION
+            "Drift of system clock expressed in microseconds with saturation to
+            min/max integer values"
+    ::= { wrsCurrentTimeGroup 12 }
+
 --wrsBootStatusGroup (.7.1.2)
 wrsBootStatusGroup      OBJECT IDENTIFIER ::= { wrsOperationStatus 2 }
 

userspace/snmpd/oids.txt

@@ -66,6 +66,7 @@
 "wrsLeapSecStatusDetails"			"1.3.6.1.4.1.96.100.7.1.1.9"
 "wrsLeapSecSourceStatusDetails"			"1.3.6.1.4.1.96.100.7.1.1.10"
 "wrsLeapSecSourceURL"			"1.3.6.1.4.1.96.100.7.1.1.11"
+"wrsSystemClockDriftUs"			"1.3.6.1.4.1.96.100.7.1.1.12"
 "wrsBootStatusGroup"			"1.3.6.1.4.1.96.100.7.1.2"
 "wrsBootCnt"			"1.3.6.1.4.1.96.100.7.1.2.1"
 "wrsRebootCnt"			"1.3.6.1.4.1.96.100.7.1.2.2"

userspace/snmpd/wrsCurrentTimeGroup.c

@@ -54,6 +54,7 @@ static struct pickinfo wrsCurrentTime_pickinfo[] = {
 	FIELD(wrsCurrentTime_s, ASN_INTEGER, wrsLeapSecStatusDetails),
 	FIELD(wrsCurrentTime_s, ASN_INTEGER, wrsLeapSecSourceStatusDetails),
 	FIELD(wrsCurrentTime_s, ASN_OCTET_STR, wrsLeapSecSourceUrl),
+	FIELD(wrsCurrentTime_s, ASN_INTEGER, wrsSystemClockDriftUs),
 };
 
 static service_exp_t services[]={
@@ -176,7 +177,9 @@ static void get_wrsSystemClockStatusDetails(void){
 	static int first_run=1;
 	char buff[21]; /* 1 for null char */
 	FILE *f;
-	int status=0, drift=0;
+	int status = 0;
+	int drift = 0;
+	int drift_us = 0;
 	static int 	threshold=0, unit=0, checkInterval=0;
 
 	update_expected_services();
@@ -212,10 +215,11 @@ static void get_wrsSystemClockStatusDetails(void){
 
 			if ((f=fopen(SYSTEMCLOCK_DRIFT, "r"))!=NULL) {
 				/* readline without newline */
-				if ( fscanf(f, "%d", &drift)!=1 ) {
+				if (fscanf(f, "%d.%d", &drift, &drift_us) != 2) {
 					snmp_log(LOG_ERR, "SNMP: " SL_ER " %s: invalid "
 						 "drift value in file " SYSTEMCLOCK_DRIFT "\n",slog_obj_name);
-					drift=0;
+					drift = 0;
+					drift_us = 0;
 				}
 				fclose(f);
 			} else {
@@ -270,6 +274,7 @@ static void get_wrsSystemClockStatusDetails(void){
 	}
 	wrsCurrentTime_s.wrsSystemClockStatusDetails = status;
 	wrsCurrentTime_s.wrsSystemClockDrift = drift;
+	wrsCurrentTime_s.wrsSystemClockDriftUs = int_saturate((int64_t)drift * 1000000 + (int64_t)drift_us);
 	wrsCurrentTime_s.wrsSystemClockDriftThreshold=threshold;
 	wrsCurrentTime_s.wrsSystemClockCheckInterval=checkInterval;
 	wrsCurrentTime_s.wrsSystemClockCheckIntervalUnit=unit;

userspace/snmpd/wrsCurrentTimeGroup.h

@@ -55,6 +55,7 @@ struct wrsCurrentTime_s {
 	int wrsLeapSecSourceStatusDetails; /* Leap second source status details*/
 	int wrsLeapSecSource;       /* Source of the leap seconds file */
 	char wrsLeapSecSourceUrl[WRS_LEAP_SECOND_SOURCE_URL_LEN + 1]; /* URL to download leap second file */
+	int wrsSystemClockDriftUs;    /* Current system clock drift value in us */
 };
 
 extern struct wrsCurrentTime_s wrsCurrentTime_s;