# main section 
my (
	$sysChassisID, #and other stuff
);

# define OID of system Chassis ID attribute (serial number)
my @sysChassisIDOID = (
	"1.3.6.1.4.1.9.3.6.3",		# .chassisId
	"1.3.6.1.2.1.47.1.1.1.1.11.0",	# .entPhysicalSerialNumber.0
	"1.3.6.1.2.1.47.1.1.1.1.11.1",	# .entPhysicalSerialNumber.1
	"1.3.6.1.4.1.9.5.1.2.19.0",	# .CiscoStackMIB.chassisSerialNumberString
);

# calling the sub: (this takes place inside a while loop as 
# the script goes through a list of IP addresses.
# I borrowed heavily from cdppoll.pl.

$sysChassisID = getSnmpInfo (@sysChassisIDOID)


sub getSnmpInfo {
	my($crap , $value , $result);
	my $varType = ref($_[0]);	# Get the variable type from ref()
	if ($varType eq "ARRAY") {
		my @tmp = $_[0];
		print "\n    DEBUG::GET_SNMP_INFO: OID is an array" if $debugging;
		# march through the array until a valid value is collected then
	# return that value.
	while (@tmp) {
		my $tOID = shift @tmp;
		$value = getSnmpInfo($tOID);
		return $value if ((ref($value) eq "SCALAR") and ($value =~ m/[A-Za-z0-9]{1,}/));
		next;
	}
	} elsif ($varType eq "SCALAR") {
			print "\n    DEBUG::GET_SNMP_INFO: OID is a scalar" if $debugging;
	} else {
			print "\n    DEBUG:GET_SNMP_INFO:: OID is an illegal variable type ($varType)" if $debugging;
		return 0;
	}
	
	my($oid) = $_[0];
	$session = (defined $_[1]) ? ($_[1]) : ($session);
	unless ($session) {
		print "\n    DEBUG::GET_SNMP_INFO: session not established in getSnmpInfo sub-routine, check scopes and pass as option 2 to getSnmpInfo" if $debugging;
		print "\n    WARN::GET_SNMP_INFO: getSnmpInfo returning null, session unavailable.";
		return 0;
	}
	print "\n    DEBUG::GET_SNMP_INFO: fetching OID: $oid" if $debugging;
	$result = $session->get_request("$oid");
	return unless (defined $result);
	($crap , $value) = %$result;
	print "\n    DEBUG::GET_SNMP_INFO: OID value: $value" if $debugging;
	return $value;
}