1 files changed, 114 insertions, 0 deletions
diff --git a/plugins/check_snmp_if b/plugins/check_snmp_if
new file mode 100755
index 0000000..5d56ae3
--- /dev/null
+++ b/plugins/check_snmp_if
@@ -0,0 +1,114 @@
+#!/bin/bash
+
+# https://ixnfo.com/en/snmp-oid-and-mib-for-interfaces.html
+# https://oidref.com/1.3.6.1.2.1.2.2.1
+# https://bestmonitoringtools.com/mibdb/mibdb_search.php?mib=IF-MIB
+
+RESULTS=(OK WARNING CRITICAL UNKNOWN)
+
+readonly MIB_IFOPERSTATUS="1.3.6.1.2.1.2.2.1.8"
+readonly MIB_ALIAS="1.3.6.1.2.1.31.1.1.1.18"
+readonly MIB_NAME="1.3.6.1.2.1.31.1.1.1.1"
+readonly MIB_IN="1.3.6.1.2.1.31.1.1.1.6"
+readonly MIB_OUT="1.3.6.1.2.1.31.1.1.1.10"
+readonly MIB_ERR_IN="1.3.6.1.2.1.2.2.1.14"
+readonly MIB_ERR_OUT="1.3.6.1.2.1.2.2.1.20"
+
+perror() {
+	echo "$@"
+} >&2
+
+fail() {
+	local RET=$1
+	shift
+	perror "$@"
+	exit $RET
+}
+
+result() {
+	local RET=$1
+	shift
+	echo -n "SNMP IF ${RESULTS[$RET]}: $@"
+	perfdata
+	exit $RET
+}
+
+walk() {
+	snmpwalk $AUTH "$HOSTNAME" "$1"
+	return $?
+}
+
+extract_val()  {
+	sed -n 's/.*=\(.*\)/\1/p' | sed -n 's/.*:\s*\(.*\)/\1/p'  | tr -d "\"'"
+}
+
+perfdata() {
+	[ $GENPERFDATA -eq 0 ] && return
+
+	echo -n "| "
+	echo -n "in=$INOCTETS "
+	echo -n "out=$OUTOCTETS "
+	echo -n "in_err=$INERRORS "
+	echo -n "out_err=$OUTERRORS "
+	echo
+}
+
+GENPERFDATA=0
+
+while getopts ":H:c:i:u:p:" opt; do
+	case $opt in
+		H)
+			HOSTNAME="$OPTARG"
+			;;
+		c)
+			COMMUNITY="$OPTARG"
+			;;
+		i)
+			INTERFACE="$OPTARG"
+			;;
+		u)
+			SNMP_USER="$OPTARG"
+			;;
+		p)
+			SNMP_PW="$OPTARG"
+			;;
+		:)
+			fail 3 "$OPTARG requires Argument."
+			;;
+		*)
+			fail 3 "Invalid option $OPTARG"
+	esac
+done
+
+AUTH=""
+if [ -n "$COMMUNITY" ]; then
+	AUTH="-c $COMMUNITY -v 2c"
+elif [ -n "$SNMP_USER" ] && [ -n "$SNMP_PW" ]; then
+	AUTH="-v 3 -u $SNMP_USER -A $SNMP_PW -l authNoPriv"
+else
+	result 3 "No or insufficient authentication info provided"
+fi
+
+SNMPWALK_RESULT=$(walk "$MIB_IFOPERSTATUS.$INTERFACE"; exit $?)
+RET=$?
+
+[ $RET -ne 0 ] && result 3 "snmpwalk failed with code $RET: $SNMPWALK_RESULT"
+[ -z "$SNMPWALK_RESULT" ] && result 2 "No matching entry found."
+
+GENPERFDATA=1
+
+NAME=$(walk "$MIB_NAME.$INTERFACE" | extract_val)
+ALIAS=$(walk "$MIB_ALIAS.$INTERFACE" | extract_val)
+
+COMPLETE_NAME="$NAME"
+if [ -n "$ALIAS" ]; then COMPLETE_NAME+=" ($ALIAS)"; fi
+
+INOCTETS=$(walk "$MIB_IN.$INTERFACE" | extract_val)
+OUTOCTETS=$(walk "$MIB_OUT.$INTERFACE" | extract_val)
+
+INERRORS=$(walk "$MIB_ERR_IN.$INTERFACE" | extract_val)
+OUTERRORS=$(walk "$MIB_ERR_OUT.$INTERFACE" | extract_val)
+
+extract_val <<< "$SNMPWALK_RESULT" | grep "up\|1" > /dev/null && result 0 "$COMPLETE_NAME is up."
+
+result 2 "$COMPLETE_NAME $INTERFACE is not up: $SNMPWALK_RESULT"