### - *- mode: Perl -*-
######################################################################
### SNMP_util -- SNMP utilities using SNMP_Session.pm and BER.pm
######################################################################
### Copyright (c) 1998-2002, Mike Mitchell.
###
### This program is free software; you can redistribute it under the
### "Artistic License" included in this distribution (file "Artistic").
######################################################################
### Created by:  Mike Mitchell   <Mike.Mitchell@sas.com>
###
### Contributions and fixes by:
###
### Tobias Oetiker <oetiker@ee.ethz.ch>:  Basic layout
### Simon Leinen <simon@switch.ch>: SNMP_session.pm/BER.pm
### Jeff Allen <jeff.allen@acm.org>: length() of undefined value
### Johannes Demel <demel@zid.tuwien.ac.at>: MIB file parse problem
### Simon Leinen <simon@switch.ch>: more OIDs from Interface MIB
### Jacques Supcik <supcik@ip-plus.net>: Specify local IP, port
### Tobias Oetiker <oetiker@ee.ethz.ch>: HASH as first OID to set SNMP options
### Simon Leinen <simon@switch.ch>: 'undefined port' bug
### Daniel McDonald <dmcdonald@digicontech.com>: request for getbulk support
### Laurent Girod <girod.laurent@pmintl.ch>: code for snmpwalkhash
### Ian Duplisse <i.duplisse@cablelabs.com>: MIB parsing suggestions
######################################################################

package SNMP_util;

require 5.004;

use strict;
use vars qw(@ISA @EXPORT $VERSION);
use Exporter;
use Carp;

use BER "0.82";
use SNMP_Session "0.83";
use Socket;

$VERSION = '0.92';

@ISA = qw(Exporter);

@EXPORT = qw(snmpget snmpgetnext snmpwalk snmpset snmptrap snmpgetbulk snmpmaptable snmpmaptable4 snmpwalkhash snmpmapOID snmpMIB_to_OID snmpLoad_OID_Cache snmpQueue_MIB_File);

# The OID numbers from RFC1213 (MIB-II) and RFC1315 (Frame Relay)
# are pre-loaded below.
%SNMP_util::OIDS = 
  (
    'iso' => '1',
    'org' => '1.3',
    'dod' => '1.3.6',
    'internet' => '1.3.6.1',
    'directory' => '1.3.6.1.1',
    'mgmt' => '1.3.6.1.2',
    'mib-2' => '1.3.6.1.2.1',
    'system' => '1.3.6.1.2.1.1',
    'sysDescr' => '1.3.6.1.2.1.1.1.0',
    'sysObjectID' => '1.3.6.1.2.1.1.2.0',
    'sysUpTime' => '1.3.6.1.2.1.1.3.0',
    'sysUptime' => '1.3.6.1.2.1.1.3.0',
    'sysContact' => '1.3.6.1.2.1.1.4.0',
    'sysName' => '1.3.6.1.2.1.1.5.0',
    'sysLocation' => '1.3.6.1.2.1.1.6.0',
    'sysServices' => '1.3.6.1.2.1.1.7.0',
    'interfaces' => '1.3.6.1.2.1.2',
    'ifNumber' => '1.3.6.1.2.1.2.1.0',
    'ifTable' => '1.3.6.1.2.1.2.2',
    'ifEntry' => '1.3.6.1.2.1.2.2.1',
    'ifIndex' => '1.3.6.1.2.1.2.2.1.1',
    'ifInOctets' => '1.3.6.1.2.1.2.2.1.10',
    'ifInUcastPkts' => '1.3.6.1.2.1.2.2.1.11',
    'ifInNUcastPkts' => '1.3.6.1.2.1.2.2.1.12',
    'ifInDiscards' => '1.3.6.1.2.1.2.2.1.13',
    'ifInErrors' => '1.3.6.1.2.1.2.2.1.14',
    'ifInUnknownProtos' => '1.3.6.1.2.1.2.2.1.15',
    'ifOutOctets' => '1.3.6.1.2.1.2.2.1.16',
    'ifOutUcastPkts' => '1.3.6.1.2.1.2.2.1.17',
    'ifOutNUcastPkts' => '1.3.6.1.2.1.2.2.1.18',
    'ifOutDiscards' => '1.3.6.1.2.1.2.2.1.19',
    'ifDescr' => '1.3.6.1.2.1.2.2.1.2',
    'ifOutErrors' => '1.3.6.1.2.1.2.2.1.20',
    'ifOutQLen' => '1.3.6.1.2.1.2.2.1.21',
    'ifSpecific' => '1.3.6.1.2.1.2.2.1.22',
    'ifType' => '1.3.6.1.2.1.2.2.1.3',
    'ifMtu' => '1.3.6.1.2.1.2.2.1.4',
    'ifSpeed' => '1.3.6.1.2.1.2.2.1.5',
    'ifPhysAddress' => '1.3.6.1.2.1.2.2.1.6',
    'ifAdminHack' => '1.3.6.1.2.1.2.2.1.7',  
    'ifAdminStatus' => '1.3.6.1.2.1.2.2.1.7',
    'ifOperHack' => '1.3.6.1.2.1.2.2.1.8',             
    'ifOperStatus' => '1.3.6.1.2.1.2.2.1.8',
    'ifLastChange' => '1.3.6.1.2.1.2.2.1.9',
    'at' => '1.3.6.1.2.1.3',
    'atTable' => '1.3.6.1.2.1.3.1',
    'atEntry' => '1.3.6.1.2.1.3.1.1',
    'atIfIndex' => '1.3.6.1.2.1.3.1.1.1',
    'atPhysAddress' => '1.3.6.1.2.1.3.1.1.2',
    'atNetAddress' => '1.3.6.1.2.1.3.1.1.3',
    'ip' => '1.3.6.1.2.1.4',
    'ipForwarding' => '1.3.6.1.2.1.4.1',
    'ipOutRequests' => '1.3.6.1.2.1.4.10',
    'ipOutDiscards' => '1.3.6.1.2.1.4.11',
    'ipOutNoRoutes' => '1.3.6.1.2.1.4.12',
    'ipReasmTimeout' => '1.3.6.1.2.1.4.13',
    'ipReasmReqds' => '1.3.6.1.2.1.4.14',
    'ipReasmOKs' => '1.3.6.1.2.1.4.15',
    'ipReasmFails' => '1.3.6.1.2.1.4.16',
    'ipFragOKs' => '1.3.6.1.2.1.4.17',
    'ipFragFails' => '1.3.6.1.2.1.4.18',
    'ipFragCreates' => '1.3.6.1.2.1.4.19',
    'ipDefaultTTL' => '1.3.6.1.2.1.4.2',
    'ipAddrTable' => '1.3.6.1.2.1.4.20',
    'ipAddrEntry' => '1.3.6.1.2.1.4.20.1',
    'ipAdEntAddr' => '1.3.6.1.2.1.4.20.1.1',
    'ipAdEntIfIndex' => '1.3.6.1.2.1.4.20.1.2',
    'ipAdEntNetMask' => '1.3.6.1.2.1.4.20.1.3',
    'ipAdEntBcastAddr' => '1.3.6.1.2.1.4.20.1.4',
    'ipAdEntReasmMaxSize' => '1.3.6.1.2.1.4.20.1.5',
    'ipRouteTable' => '1.3.6.1.2.1.4.21',
    'ipRouteEntry' => '1.3.6.1.2.1.4.21.1',
    'ipRouteDest' => '1.3.6.1.2.1.4.21.1.1',
    'ipRouteAge' => '1.3.6.1.2.1.4.21.1.10',
    'ipRouteMask' => '1.3.6.1.2.1.4.21.1.11',
    'ipRouteMetric5' => '1.3.6.1.2.1.4.21.1.12',
    'ipRouteInfo' => '1.3.6.1.2.1.4.21.1.13',
    'ipRouteIfIndex' => '1.3.6.1.2.1.4.21.1.2',
    'ipRouteMetric1' => '1.3.6.1.2.1.4.21.1.3',
    'ipRouteMetric2' => '1.3.6.1.2.1.4.21.1.4',
    'ipRouteMetric3' => '1.3.6.1.2.1.4.21.1.5',
    'ipRouteMetric4' => '1.3.6.1.2.1.4.21.1.6',
    'ipRouteNextHop' => '1.3.6.1.2.1.4.21.1.7',
    'ipRouteType' => '1.3.6.1.2.1.4.21.1.8',
    'ipRouteProto' => '1.3.6.1.2.1.4.21.1.9',
    'ipNetToMediaTable' => '1.3.6.1.2.1.4.22',
    'ipNetToMediaEntry' => '1.3.6.1.2.1.4.22.1',
    'ipNetToMediaIfIndex' => '1.3.6.1.2.1.4.22.1.1',
    'ipNetToMediaPhysAddress' => '1.3.6.1.2.1.4.22.1.2',
    'ipNetToMediaNetAddress' => '1.3.6.1.2.1.4.22.1.3',
    'ipNetToMediaType' => '1.3.6.1.2.1.4.22.1.4',
    'ipRoutingDiscards' => '1.3.6.1.2.1.4.23',
    'ipInReceives' => '1.3.6.1.2.1.4.3',
    'ipInHdrErrors' => '1.3.6.1.2.1.4.4',
    'ipInAddrErrors' => '1.3.6.1.2.1.4.5',
    'ipForwDatagrams' => '1.3.6.1.2.1.4.6',
    'ipInUnknownProtos' => '1.3.6.1.2.1.4.7',
    'ipInDiscards' => '1.3.6.1.2.1.4.8',
    'ipInDelivers' => '1.3.6.1.2.1.4.9',
    'icmp' => '1.3.6.1.2.1.5',
    'icmpInMsgs' => '1.3.6.1.2.1.5.1',
    'icmpInTimestamps' => '1.3.6.1.2.1.5.10',
    'icmpInTimestampReps' => '1.3.6.1.2.1.5.11',
    'icmpInAddrMasks' => '1.3.6.1.2.1.5.12',
    'icmpInAddrMaskReps' => '1.3.6.1.2.1.5.13',
    'icmpOutMsgs' => '1.3.6.1.2.1.5.14',
    'icmpOutErrors' => '1.3.6.1.2.1.5.15',
    'icmpOutDestUnreachs' => '1.3.6.1.2.1.5.16',
    'icmpOutTimeExcds' => '1.3.6.1.2.1.5.17',
    'icmpOutParmProbs' => '1.3.6.1.2.1.5.18',
    'icmpOutSrcQuenchs' => '1.3.6.1.2.1.5.19',
    'icmpInErrors' => '1.3.6.1.2.1.5.2',
    'icmpOutRedirects' => '1.3.6.1.2.1.5.20',
    'icmpOutEchos' => '1.3.6.1.2.1.5.21',
    'icmpOutEchoReps' => '1.3.6.1.2.1.5.22',
    'icmpOutTimestamps' => '1.3.6.1.2.1.5.23',
    'icmpOutTimestampReps' => '1.3.6.1.2.1.5.24',
    'icmpOutAddrMasks' => '1.3.6.1.2.1.5.25',
    'icmpOutAddrMaskReps' => '1.3.6.1.2.1.5.26',
    'icmpInDestUnreachs' => '1.3.6.1.2.1.5.3',
    'icmpInTimeExcds' => '1.3.6.1.2.1.5.4',
    'icmpInParmProbs' => '1.3.6.1.2.1.5.5',
    'icmpInSrcQuenchs' => '1.3.6.1.2.1.5.6',
    'icmpInRedirects' => '1.3.6.1.2.1.5.7',
    'icmpInEchos' => '1.3.6.1.2.1.5.8',
    'icmpInEchoReps' => '1.3.6.1.2.1.5.9',
    'tcp' => '1.3.6.1.2.1.6',
    'tcpRtoAlgorithm' => '1.3.6.1.2.1.6.1',
    'tcpInSegs' => '1.3.6.1.2.1.6.10',
    'tcpOutSegs' => '1.3.6.1.2.1.6.11',
    'tcpRetransSegs' => '1.3.6.1.2.1.6.12',
    'tcpConnTable' => '1.3.6.1.2.1.6.13',
    'tcpConnEntry' => '1.3.6.1.2.1.6.13.1',
    'tcpConnState' => '1.3.6.1.2.1.6.13.1.1',
    'tcpConnLocalAddress' => '1.3.6.1.2.1.6.13.1.2',
    'tcpConnLocalPort' => '1.3.6.1.2.1.6.13.1.3',
    'tcpConnRemAddress' => '1.3.6.1.2.1.6.13.1.4',
    'tcpConnRemPort' => '1.3.6.1.2.1.6.13.1.5',
    'tcpInErrs' => '1.3.6.1.2.1.6.14',
    'tcpOutRsts' => '1.3.6.1.2.1.6.15',
    'tcpRtoMin' => '1.3.6.1.2.1.6.2',
    'tcpRtoMax' => '1.3.6.1.2.1.6.3',
    'tcpMaxConn' => '1.3.6.1.2.1.6.4',
    'tcpActiveOpens' => '1.3.6.1.2.1.6.5',
    'tcpPassiveOpens' => '1.3.6.1.2.1.6.6',
    'tcpAttemptFails' => '1.3.6.1.2.1.6.7',
    'tcpEstabResets' => '1.3.6.1.2.1.6.8',
    'tcpCurrEstab' => '1.3.6.1.2.1.6.9',
    'udp' => '1.3.6.1.2.1.7',
    'udpInDatagrams' => '1.3.6.1.2.1.7.1',
    'udpNoPorts' => '1.3.6.1.2.1.7.2',
    'udpInErrors' => '1.3.6.1.2.1.7.3',
    'udpOutDatagrams' => '1.3.6.1.2.1.7.4',
    'udpTable' => '1.3.6.1.2.1.7.5',
    'udpEntry' => '1.3.6.1.2.1.7.5.1',
    'udpLocalAddress' => '1.3.6.1.2.1.7.5.1.1',
    'udpLocalPort' => '1.3.6.1.2.1.7.5.1.2',
    'egp' => '1.3.6.1.2.1.8',
    'egpInMsgs' => '1.3.6.1.2.1.8.1',
    'egpInErrors' => '1.3.6.1.2.1.8.2',
    'egpOutMsgs' => '1.3.6.1.2.1.8.3',
    'egpOutErrors' => '1.3.6.1.2.1.8.4',
    'egpNeighTable' => '1.3.6.1.2.1.8.5',
    'egpNeighEntry' => '1.3.6.1.2.1.8.5.1',
    'egpNeighState' => '1.3.6.1.2.1.8.5.1.1',
    'egpNeighStateUps' => '1.3.6.1.2.1.8.5.1.10',
    'egpNeighStateDowns' => '1.3.6.1.2.1.8.5.1.11',
    'egpNeighIntervalHello' => '1.3.6.1.2.1.8.5.1.12',
    'egpNeighIntervalPoll' => '1.3.6.1.2.1.8.5.1.13',
    'egpNeighMode' => '1.3.6.1.2.1.8.5.1.14',
    'egpNeighEventTrigger' => '1.3.6.1.2.1.8.5.1.15',
    'egpNeighAddr' => '1.3.6.1.2.1.8.5.1.2',
    'egpNeighAs' => '1.3.6.1.2.1.8.5.1.3',
    'egpNeighInMsgs' => '1.3.6.1.2.1.8.5.1.4',
    'egpNeighInErrs' => '1.3.6.1.2.1.8.5.1.5',
    'egpNeighOutMsgs' => '1.3.6.1.2.1.8.5.1.6',
    'egpNeighOutErrs' => '1.3.6.1.2.1.8.5.1.7',
    'egpNeighInErrMsgs' => '1.3.6.1.2.1.8.5.1.8',
    'egpNeighOutErrMsgs' => '1.3.6.1.2.1.8.5.1.9',
    'egpAs' => '1.3.6.1.2.1.8.6',
    'transmission' => '1.3.6.1.2.1.10',
    'frame-relay' => '1.3.6.1.2.1.10.32',
    'frDlcmiTable' => '1.3.6.1.2.1.10.32.1',
    'frDlcmiEntry' => '1.3.6.1.2.1.10.32.1.1',
    'frDlcmiIfIndex' => '1.3.6.1.2.1.10.32.1.1.1',
    'frDlcmiState' => '1.3.6.1.2.1.10.32.1.1.2',
    'frDlcmiAddress' => '1.3.6.1.2.1.10.32.1.1.3',
    'frDlcmiAddressLen' => '1.3.6.1.2.1.10.32.1.1.4',
    'frDlcmiPollingInterval' => '1.3.6.1.2.1.10.32.1.1.5',
    'frDlcmiFullEnquiryInterval' => '1.3.6.1.2.1.10.32.1.1.6',
    'frDlcmiErrorThreshold' => '1.3.6.1.2.1.10.32.1.1.7',
    'frDlcmiMonitoredEvents' => '1.3.6.1.2.1.10.32.1.1.8',
    'frDlcmiMaxSupportedVCs' => '1.3.6.1.2.1.10.32.1.1.9',
    'frDlcmiMulticast' => '1.3.6.1.2.1.10.32.1.1.10',
    'frCircuitTable' => '1.3.6.1.2.1.10.32.2',
    'frCircuitEntry' => '1.3.6.1.2.1.10.32.2.1',
    'frCircuitIfIndex' => '1.3.6.1.2.1.10.32.2.1.1',
    'frCircuitDlci' => '1.3.6.1.2.1.10.32.2.1.2',
    'frCircuitState' => '1.3.6.1.2.1.10.32.2.1.3',
    'frCircuitReceivedFECNs' => '1.3.6.1.2.1.10.32.2.1.4',
    'frCircuitReceivedBECNs' => '1.3.6.1.2.1.10.32.2.1.5',
    'frCircuitSentFrames' => '1.3.6.1.2.1.10.32.2.1.6',
    'frCircuitSentOctets' => '1.3.6.1.2.1.10.32.2.1.7',
    'frOutOctets' => '1.3.6.1.2.1.10.32.2.1.7',
    'frCircuitReceivedFrames' => '1.3.6.1.2.1.10.32.2.1.8',
    'frCircuitReceivedOctets' => '1.3.6.1.2.1.10.32.2.1.9',
    'frInOctets' => '1.3.6.1.2.1.10.32.2.1.9',
    'frCircuitCreationTime' => '1.3.6.1.2.1.10.32.2.1.10',
    'frCircuitLastTimeChange' => '1.3.6.1.2.1.10.32.2.1.11',
    'frCircuitCommittedBurst' => '1.3.6.1.2.1.10.32.2.1.12',
    'frCircuitExcessBurst' => '1.3.6.1.2.1.10.32.2.1.13',
    'frCircuitThroughput' => '1.3.6.1.2.1.10.32.2.1.14',
    'frErrTable' => '1.3.6.1.2.1.10.32.3',
    'frErrEntry' => '1.3.6.1.2.1.10.32.3.1',
    'frErrIfIndex' => '1.3.6.1.2.1.10.32.3.1.1',
    'frErrType' => '1.3.6.1.2.1.10.32.3.1.2',
    'frErrData' => '1.3.6.1.2.1.10.32.3.1.3',
    'frErrTime' => '1.3.6.1.2.1.10.32.3.1.4',
    'frame-relay-globals' => '1.3.6.1.2.1.10.32.4',
    'frTrapState' => '1.3.6.1.2.1.10.32.4.1',
    'snmp' => '1.3.6.1.2.1.11',
    'snmpInPkts' => '1.3.6.1.2.1.11.1',
    'snmpInBadValues' => '1.3.6.1.2.1.11.10',
    'snmpInReadOnlys' => '1.3.6.1.2.1.11.11',
    'snmpInGenErrs' => '1.3.6.1.2.1.11.12',
    'snmpInTotalReqVars' => '1.3.6.1.2.1.11.13',
    'snmpInTotalSetVars' => '1.3.6.1.2.1.11.14',
    'snmpInGetRequests' => '1.3.6.1.2.1.11.15',
    'snmpInGetNexts' => '1.3.6.1.2.1.11.16',
    'snmpInSetRequests' => '1.3.6.1.2.1.11.17',
    'snmpInGetResponses' => '1.3.6.1.2.1.11.18',
    'snmpInTraps' => '1.3.6.1.2.1.11.19',
    'snmpOutPkts' => '1.3.6.1.2.1.11.2',
    'snmpOutTooBigs' => '1.3.6.1.2.1.11.20',
    'snmpOutNoSuchNames' => '1.3.6.1.2.1.11.21',
    'snmpOutBadValues' => '1.3.6.1.2.1.11.22',
    'snmpOutGenErrs' => '1.3.6.1.2.1.11.24',
    'snmpOutGetRequests' => '1.3.6.1.2.1.11.25',
    'snmpOutGetNexts' => '1.3.6.1.2.1.11.26',
    'snmpOutSetRequests' => '1.3.6.1.2.1.11.27',
    'snmpOutGetResponses' => '1.3.6.1.2.1.11.28',
    'snmpOutTraps' => '1.3.6.1.2.1.11.29',
    'snmpInBadVersions' => '1.3.6.1.2.1.11.3',
    'snmpEnableAuthenTraps' => '1.3.6.1.2.1.11.30',
    'snmpInBadCommunityNames' => '1.3.6.1.2.1.11.4',
    'snmpInBadCommunityUses' => '1.3.6.1.2.1.11.5',
    'snmpInASNParseErrs' => '1.3.6.1.2.1.11.6',
    'snmpInTooBigs' => '1.3.6.1.2.1.11.8',
    'snmpInNoSuchNames' => '1.3.6.1.2.1.11.9',
    'ifName' => '1.3.6.1.2.1.31.1.1.1.1',
    'ifInMulticastPkts' => '1.3.6.1.2.1.31.1.1.1.2',
    'ifInBroadcastPkts' => '1.3.6.1.2.1.31.1.1.1.3',
    'ifOutMulticastPkts' => '1.3.6.1.2.1.31.1.1.1.4',
    'ifOutBroadcastPkts' => '1.3.6.1.2.1.31.1.1.1.5',
    'ifHCInOctets' => '1.3.6.1.2.1.31.1.1.1.6',
    'ifHCInUcastPkts' => '1.3.6.1.2.1.31.1.1.1.7',
    'ifHCInMulticastPkts' => '1.3.6.1.2.1.31.1.1.1.8',
    'ifHCInBroadcastPkts' => '1.3.6.1.2.1.31.1.1.1.9',
    'ifHCOutOctets' => '1.3.6.1.2.1.31.1.1.1.10',
    'ifHCOutUcastPkts' => '1.3.6.1.2.1.31.1.1.1.11',
    'ifHCOutMulticastPkts' => '1.3.6.1.2.1.31.1.1.1.12',
    'ifHCOutBroadcastPkts' => '1.3.6.1.2.1.31.1.1.1.13',
    'ifLinkUpDownTrapEnable' => '1.3.6.1.2.1.31.1.1.1.14',
    'ifHighSpeed' => '1.3.6.1.2.1.31.1.1.1.15',
    'ifPromiscuousMode' => '1.3.6.1.2.1.31.1.1.1.16',
    'ifConnectorPresent' => '1.3.6.1.2.1.31.1.1.1.17',
    'ifAlias' => '1.3.6.1.2.1.31.1.1.1.18',
    'ifCounterDiscontinuityTime' => '1.3.6.1.2.1.31.1.1.1.19',
    'experimental' => '1.3.6.1.3',
    'private' => '1.3.6.1.4',
    'enterprises' => '1.3.6.1.4.1',
  );

# GIL
my %revOIDS = ();	# Reversed %SNMP_util::OIDS hash
my $RevNeeded = 1;

my $agent_start_time = time;

undef $SNMP_util::Host;
undef $SNMP_util::Session;
undef $SNMP_util::Version;
undef $SNMP_util::LHost;
$SNMP_util::Debug = 0;
$SNMP_util::CacheFile = "OID_cache.txt";
$SNMP_util::CacheLoaded = 0;

srand(time + $$);

### Prototypes
sub snmpget ($@);
sub snmpgetnext ($@);
sub snmpopen ($$$);
sub snmpwalk ($@);
sub snmpwalk_flg ($$@);
sub snmpset ($@);
sub snmptrap ($$$$$@);
sub snmpgetbulk ($$$@);
sub snmpmaptable ($$@);
sub snmpmaptable4 ($$$@);
sub snmpwalkhash ($$@);
sub toOID (@);
sub snmpmapOID (@);
sub snmpMIB_to_OID ($);
sub encode_oid_with_errmsg ($);
sub Check_OID ($);
sub snmpLoad_OID_Cache ($);
sub snmpQueue_MIB_File (@);

sub version () { $VERSION; }

#
# Start an snmp session
#
sub snmpopen ($$$) {
  my($host, $type, $vars) = @_;
  my($nhost, $port, $community, $lhost, $lport, $nlhost);
  my($timeout, $retries, $backoff, $version);

  $type = 0 if (!defined($type));
  $community = "public";
  $nlhost = "";

  ($community, $host) = ($1, $2) if ($host =~ /^(.*)@([^@]+)$/);
  ($host, $port, $timeout, $retries, $backoff, $version) = split(':', $host, 6)
    if ($host =~ /:/);
  $version = '1' unless defined $version;
  if (defined($port) && ($port =~ /^([^!]*)!(.*)$/)) {
    ($port, $lhost) = ($1, $2);
    $nlhost = $lhost;
    ($lhost, $lport) = ($1, $2) if ($lhost =~ /^(.*)!(.*)$/);
    undef($lhost) if (defined($lhost) && (length($lhost) <= 0));
    undef($lport) if (defined($lport) && (length($lport) <= 0));
  }
  undef($port) if (defined($port) && length($port) <= 0);
  $port = 162 if ($type == 1 && !defined($port));
  $nhost = "$community\@$host";
  $nhost .= ":" . $port if (defined($port));

  if ((!defined($SNMP_util::Session))
    || ($SNMP_util::Host ne $nhost)
    || ($SNMP_util::Version ne $version)
    || ($SNMP_util::LHost ne $nlhost)) {
    if (defined($SNMP_util::Session)) {
      $SNMP_util::Session->close();    
      undef $SNMP_util::Session;
      undef $SNMP_util::Host;
      undef $SNMP_util::Version;
      undef $SNMP_util::LHost;
    }
    $SNMP_util::Session = ($version =~ /^2c?$/i)
      ? SNMPv2c_Session->open($host, $community, $port, undef,
				$lport, undef, $lhost)
      : SNMP_Session->open($host, $community, $port, undef,
				$lport, undef, $lhost);
    ($SNMP_util::Host = $nhost, $SNMP_util::Version = $version,
      $SNMP_util::LHost = $nlhost) if defined($SNMP_util::Session);
  }

  if (defined($SNMP_util::Session)) {
    if (ref $vars->[0] eq 'HASH') {
      my $opts = shift @$vars;
      foreach $type (keys %$opts) {
	if (exists $SNMP_util::Session->{$type}) {
	  if ($type eq 'timeout') {
	    $SNMP_util::Session->set_timeout($opts->{$type});
	  } elsif ($type eq 'retries') {
	    $SNMP_util::Session->set_retries($opts->{$type});
	  } elsif ($type eq 'backoff') {
	    $SNMP_util::Session->set_backoff($opts->{$type});
	  } else {
	    $SNMP_util::Session->{$type} = $opts->{$type};
	  }
	} else {
	  carp "SNMPopen Unknown SNMP Option Key '$type'\n"
	    unless ($SNMP_Session::suppress_warnings > 1);
	}
      }
    }
    $SNMP_util::Session->set_timeout($timeout)
      if (defined($timeout) && (length($timeout) > 0));
    $SNMP_util::Session->set_retries($retries)
      if (defined($retries) && (length($retries) > 0));
    $SNMP_util::Session->set_backoff($backoff)
      if (defined($backoff) && (length($backoff) > 0));
  }
  return $SNMP_util::Session;
}


#
# A restricted snmpget.
#
sub snmpget ($@) {
  my($host, @vars) = @_;
  my(@enoid, $var, $response, $bindings, $binding, $value, $oid, @retvals);
  my $session;

  $session = &snmpopen($host, 0, \@vars);
  if (!defined($session)) {
    carp "SNMPGET Problem for $host\n"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }

  @enoid = &toOID(@vars);
  return undef unless defined $enoid[0];

  if ($session->get_request_response(@enoid)) {
    $response = $session->pdu_buffer;
    ($bindings) = $session->decode_get_response($response);
    while ($bindings) {
      ($binding, $bindings) = decode_sequence($bindings);
      ($oid, $value) = decode_by_template($binding, "%O%@");
      my $tempo = pretty_print($value);
      push @retvals, $tempo;
    }
    return(@retvals);
  }
  $var = join(' ', @vars);
  carp "SNMPGET Problem for $var on $host\n"
    unless ($SNMP_Session::suppress_warnings > 1);
  return undef;
}

#
# A restricted snmpgetnext.
#
sub snmpgetnext ($@) {
  my($host, @vars) = @_;
  my(@enoid, $var, $response, $bindings, $binding);
  my($value, $upoid, $oid, @retvals);
  my($noid);
  my $session;

  $session = &snmpopen($host, 0, \@vars);
  if (!defined($session)) {
    carp "SNMPGETNEXT Problem for $host\n"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }

  @enoid = &toOID(@vars);
  return undef unless defined $enoid[0];

  undef @vars;
  undef @retvals;
  foreach $noid (@enoid) {
    $upoid = pretty_print($noid);
    push(@vars, $upoid);
  }
  if ($session->getnext_request_response(@enoid)) {
    $response = $session->pdu_buffer;
    ($bindings) = $session->decode_get_response($response);
    while ($bindings) {
      ($binding, $bindings) = decode_sequence($bindings);
      ($oid, $value) = decode_by_template($binding, "%O%@");
      my $tempo = pretty_print($oid);
      my $tempv = pretty_print($value);
      push @retvals, "$tempo:$tempv";
    }
    return (@retvals);
  } else {
    $var = join(' ', @vars);
    carp "SNMPGETNEXT Problem for $var on $host\n"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }
}

#
# A restricted snmpwalk.
#
sub snmpwalk ($@) {
  my($host, @vars) = @_;
  return(&snmpwalk_flg($host, undef, @vars));
}

#
# Walk the MIB, putting everything you find into hashes.
#
sub snmpwalkhash($$@) {
#  my($host, $hash_sub, @vars) = @_;
  return(&snmpwalk_flg( @_ ));
}

sub snmpwalk_flg ($$@) {
  my($host, $hash_sub, @vars) = @_;
  my(@enoid, $var, $response, $bindings, $binding);
  my($value, $upoid, $oid, @retvals);
  my($got, @nnoid, $noid, $ok);
  my $session;
  my(%soid);
  my(%done, %rethash);
	
  $session = &snmpopen($host, 0, \@vars);
  if (!defined($session)) {
    carp "SNMPWALK Problem for $host\n"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }

  @enoid = toOID(@vars);
  return undef unless defined $enoid[0];

  # GIL
  #
  # Create/Refresh a reversed hash with oid -> name
  #
  if (defined($hash_sub) && $RevNeeded) {
    %revOIDS = reverse %SNMP_util::OIDS;
    $RevNeeded = 0;
  }

  $got = 0;
  @nnoid = @enoid;
  undef @vars;
  foreach $noid (@enoid) {
    $upoid = pretty_print($noid);
    push(@vars, $upoid);
  }
  while(($SNMP_util::Version ne '1' && $session->{'use_getbulk'})
    ? $session->getbulk_request_response(0,
					  $session->default_max_repetitions(),
					  @nnoid)
    : $session->getnext_request_response(@nnoid))
  {
    $got = 1;
    $response = $session->pdu_buffer;
    ($bindings) = $session->decode_get_response($response);
    undef @nnoid;
    while ($bindings) {
      ($binding, $bindings) = decode_sequence($bindings);
      ($oid, $value) = decode_by_template($binding, "%O%@");
      $ok = 0;
      my $tempo = pretty_print($oid);
      foreach $noid (@vars) {
	if ($tempo =~ /^$noid\./ || $tempo eq $noid ) {
	  $ok = 1;
	  $upoid = $noid;
	  last;
	}
      }
      if ($ok) {
	my $tmp = encode_oid_with_errmsg ($tempo);
	return undef unless defined $tmp;
	next if (exists($done{$tmp}));	# GIL
	push @nnoid, $tmp;
	my $tempv = pretty_print($value);
	if (defined($hash_sub)) {
	  #
	  # extract name of the oid, if possible, the rest becomes the instance
	  #
	  my $inst;
	  while (!exists($revOIDS{$tempo}) && length($tempo)) {
	    $tempo =~ s/(\.\d+?)$//;
	    $inst = $1.$inst;
	  }	
	  #
	  # call hash_sub
	  #
	  &$hash_sub(\%rethash, $host, $revOIDS{$tempo}, $tempo, $inst, $tempv);
	} else {
	  $tempo=~s/^$upoid\.//;
	  push @retvals, "$tempo:$tempv";
	}
	$done{$tmp} = 1;	# GIL
      }
    }
    last if ($#nnoid < 0);
  }
  if ($got) {
    if (defined($hash_sub)) {
    	return (%rethash)
    } else {
    	return (@retvals);
    }
  } else {
    $var = join(' ', @vars);
    carp "SNMPWALK Problem for $var on $host\n"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }
}

#
# A restricted snmpset.
#
sub snmpset($@) {
  my($host, @vars) = @_;
  my(@enoid, $response, $bindings, $binding);
  my($oid, @retvals, $type, $value);
  my $session;

  $session = &snmpopen($host, 0, \@vars);
  if (!defined($session)) {
    carp "SNMPSET Problem for $host\n"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }

  while(@vars) {
    ($oid) = toOID((shift @vars));
    $type  = shift @vars;
    $value = shift @vars;
    if ($type =~ /string/i) {
      $value = encode_string($value);
      push @enoid, [$oid,$value];
    } elsif ($type =~ /ipaddr/i) {
      $value = encode_ip_address($value);
      push @enoid, [$oid,$value];
    } elsif ($type =~ /int/i) {
      $value = encode_int($value);
      push @enoid, [$oid,$value];
    } elsif ($type =~ /oid/i) {
      my $tmp = encode_oid_with_errmsg($value);
      return undef unless defined $tmp;
      push @enoid, [$oid,$tmp];
    } else {
      carp "unknown SNMP type: $type\n"
	unless ($SNMP_Session::suppress_warnings > 1);
      return undef;
    }
  }
  return undef unless defined $enoid[0];
  if ($session->set_request_response(@enoid)) {
    $response = $session->pdu_buffer;
    ($bindings) = $session->decode_get_response($response);
    while ($bindings) {
      ($binding, $bindings) = decode_sequence($bindings);
      ($oid, $value) = decode_by_template($binding, "%O%@");
      my $tempo = pretty_print($value);
      push @retvals, $tempo;
    }
    return (@retvals);
  }
  return undef;
}

#
# Send an SNMP trap
#
sub snmptrap($$$$$@) {
  my($host, $ent, $agent, $gen, $spec, @vars) = @_;
  my($oid, @retvals, $type, $value);
  my(@enoid);
  my $session;

  $session = &snmpopen($host, 1, \@vars);
  if (!defined($session)) {
    carp "SNMPTRAP Problem for $host\n"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }

  if ($agent =~ /^\d+\.\d+\.\d+\.\d+(.*)/ ) {
    $agent = pack("C*", split /\./, $agent);
  } else {
    $agent = inet_aton($agent);
  }
  push @enoid, toOID(($ent));
  push @enoid, encode_ip_address($agent);
  push @enoid, encode_int($gen);
  push @enoid, encode_int($spec);
  push @enoid, encode_timeticks((time-$agent_start_time) * 100);
  while(@vars) {
    ($oid) = toOID((shift @vars));
    $type  = shift @vars;
    $value = shift @vars;
    if ($type =~ /string/i) {
      $value = encode_string($value);
      push @enoid, [$oid,$value];
    } elsif ($type =~ /ipaddr/i) {
      $value = encode_ip_address($value);
      push @enoid, [$oid,$value];
    } elsif ($type =~ /int/i) {
      $value = encode_int($value);
      push @enoid, [$oid,$value];
    } elsif ($type =~ /oid/i) {
      my $tmp = encode_oid_with_errmsg($value);
      return undef unless defined $tmp;
      push @enoid, [$oid,$tmp];
    } else {
      carp "unknown SNMP type: $type\n"
	unless ($SNMP_Session::suppress_warnings > 1);
      return undef;
    }
  }
  return($session->trap_request_send(@enoid));
}

#
# A restricted snmpgetbulk.
#
sub snmpgetbulk ($$$@) {
  my($host, $nr, $mr, @vars) = @_;
  my(@enoid, $var, $response, $bindings, $binding);
  my($value, $upoid, $oid, @retvals);
  my($noid);
  my $session;

  $session = &snmpopen($host, 0, \@vars);
  if (!defined($session)) {
    carp "SNMPGETBULK Problem for $host\n"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }

  @enoid = &toOID(@vars);
  return undef unless defined $enoid[0];

  undef @vars;
  undef @retvals;
  foreach $noid (@enoid) {
    $upoid = pretty_print($noid);
    push(@vars, $upoid);
  }
  if ($session->getbulk_request_response($nr, $mr, @enoid)) {
    $response = $session->pdu_buffer;
    ($bindings) = $session->decode_get_response($response);
    while ($bindings) {
      ($binding, $bindings) = decode_sequence($bindings);
      ($oid, $value) = decode_by_template($binding, "%O%@");
      my $tempo = pretty_print($oid);
      my $tempv = pretty_print($value);
      push @retvals, "$tempo:$tempv";
    }
    return (@retvals);
  } else {
    $var = join(' ', @vars);
    carp "SNMPGETBULK Problem for $var on $host\n"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }
}

#
# walk a table, calling a user-supplied function for each
# column of a table.
#
sub snmpmaptable($$@) {
  my($host, $fun, @vars) = @_;
  return snmpmaptable4($host, $fun, 0, @vars);
}

sub snmpmaptable4($$$@) {
  my($host, $fun, $max_reps, @vars) = @_;
  my(@enoid, $var, $session);

  $session = &snmpopen($host, 0, \@vars);
  if (!defined($session)) {
    carp "SNMPMAPTABLE Problem for $host\n"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }

  foreach $var (toOID(@vars)) {
    push(@enoid, [split('\.', pretty_print($var))]);
  }

  $max_reps = $session->default_max_repetitions() if ($max_reps <= 0);

  return $session->map_table_start_end( [@enoid],
					sub() {
					  my ($ind, @vals) = @_;
					  my (@pvals, $val);

					  foreach $val (@vals) {
					    push(@pvals, pretty_print($val));
					  }
					  &$fun($ind, @pvals);
					},
					"", undef, $max_reps);
}


#
#  Given an OID in either ASN.1 or mixed text/ASN.1 notation, return an
#  encoded OID.
#
sub toOID(@) {
  my(@vars) = @_;
  my($oid, $var, $tmp, $tmpv, @retvar);

  undef @retvar;
  foreach $var (@vars) {
    ($oid, $tmp) = &Check_OID($var);
    if (!$oid && $SNMP_util::CacheLoaded == 0) {
      $tmp = $SNMP_Session::suppress_warnings;
      $SNMP_Session::suppress_warnings = 1000;

      &snmpLoad_OID_Cache($SNMP_util::CacheFile);

      $SNMP_util::CacheLoaded = 1;
      $SNMP_Session::suppress_warnings = $tmp;

      ($oid, $tmp) = &Check_OID($var);
    }
    while (!$oid && $#SNMP_util::MIB_Files >= 0) {
      $tmp = $SNMP_Session::suppress_warnings;
      $SNMP_Session::suppress_warnings = 1000;

      snmpMIB_to_OID(shift(@SNMP_util::MIB_Files));

      $SNMP_Session::suppress_warnings = $tmp;

      ($oid, $tmp) = &Check_OID($var);
      if ($oid) {
	open(CACHE, ">>$SNMP_util::CacheFile");
	print CACHE "$tmp\t$oid\n";
	close(CACHE);
      }
    }
    if ($oid) {
      $var =~ s/^$tmp/$oid/;
    } else {
      carp "Unknown SNMP var $var\n"
      unless ($SNMP_Session::suppress_warnings > 1);
      next;
    }
    if ($var =~ /\"(.*)\"/) {
      $tmp = sprintf("%d.%s", length($1), join(".", map(ord, split(//, $1))));
      $var =~ s/\".*\"/$tmp/;
    }
    print "toOID: $var\n" if $SNMP_util::Debug;
    $tmp = encode_oid_with_errmsg($var);
    return undef unless defined $tmp;
    push(@retvar, $tmp);
  }
  return @retvar;
}

#
#  Add passed-in text, OID pairs to the OID mapping table.
#
sub snmpmapOID(@)
{
  my(@vars) = @_;
  my($oid, $txt, $ind);

  $ind = 0;
  while($ind <= $#vars) {
    $txt = $vars[$ind++];
    next unless($txt =~ /^(([a-z][a-z\d\-]*\.)*([a-z][a-z\d\-]*))$/i);

    $oid = $vars[$ind++];
    next unless($oid =~ /^((\d+.)*\d+)$/);

    $SNMP_util::OIDS{$txt} = $oid;
    $RevNeeded = 1;
    print "snmpmapOID: $txt => $oid\n" if $SNMP_util::Debug;
  }
  
  return undef;
}

#
# Open the passed-in file name and read it in to populate
# the cache of text-to-OID map table.  It expects lines
# with two fields, the first the textual string like "ifInOctets",
# and the second the OID value, like "1.3.6.1.2.1.2.2.1.10".
#
# blank lines and anything after a '#' or between '--' is ignored.
#
sub snmpLoad_OID_Cache ($) {
  my($arg) = @_;
  my($txt, $oid);

  if (!open(CACHE, $arg)) {
    carp "snmpLoad_OID_Cache: Can't open $arg: $!"
      unless ($SNMP_Session::suppress_warnings > 1);
    return -1;
  }

  while(<CACHE>) {
    s/#.*//;
    s/--.*--//g;
    s/--.*//;
    next if (/^$/);
    next unless (/\s/);
    chop;
    ($txt, $oid) = split(' ', $_, 2);
    &snmpmapOID($txt, $oid);
  }
  close(CACHE);
  return 0;
}

#
# Check to see if an OID is in the text-to-OID cache.
# Returns the OID and the corresponding text as two separate
# elements.
#
sub Check_OID ($) {
  my($var) = @_;
  my($tmp, $tmpv, $oid);

  if ($var =~ /^(([a-z][a-z\d\-]*\.)*([a-z][a-z\d\-]*))/i)
  {
    $tmp = $&;
    $tmpv = $tmp;
    for (;;) {
      last if defined($SNMP_util::OIDS{$tmpv});
      last if !($tmpv =~ s/^[^\.]*\.//);
    }
    $oid = $SNMP_util::OIDS{$tmpv};
    if ($oid) {
      return ($oid, $tmp);
    } else {
      return undef;
    }
  }
  return ($var, $var);
}

#
# Save the passed-in list of MIB files until an OID can't be
# found in the existing table.  At that time the MIB file will
# be loaded, and the lookup attempted again.
#
sub snmpQueue_MIB_File (@) {
  my(@files) = @_;
  my($file);

  foreach $file (@files) {
    push(@SNMP_util::MIB_Files, $file);
  }
}

#
# Read in the passed MIB file, parsing it
# for their text-to-OID mappings
#
sub snmpMIB_to_OID ($) {
  my($arg) = @_;
  my($quote, $buf, $var, $code, $val, $tmp, $tmpv, $strt);
  my($ret, $pass, $pos, $need2pass, $cnt, %prev);
  my(%Link) = (
    'org' => 'iso',
    'dod' => 'org',
    'internet' => 'dod',
    'directory' => 'internet',
    'mgmt' => 'internet',
    'mib-2' => 'mgmt',
    'experimental' => 'internet',
    'private' => 'internet',
    'enterprises' => 'private',
  );

  if (!open(MIB, $arg)) {
    carp "snmpMIB_to_OID: Can't open $arg: $!"
      unless ($SNMP_Session::suppress_warnings > 1);
    return -1;
  }
  print "snmpMIB_to_OID: loading $arg\n" if $SNMP_util::Debug;
  $ret = 0;
  $pass = 0;
  $need2pass = 1;
  $cnt = 0;
  $pos = tell(MIB);
  while($need2pass) {
    while(<MIB>) {
      s/--.*--//g;	# throw away comments (-- anything --)
      s/--.*//;		# throw away comments (-- anything EOL)
      if ($quote) {
	next unless /"/;
	$quote = 0;
      }
      chop;
#
#	$buf = "$buf $_";
# Previous line removed (and following replacement)
# suggested by Brian Reichert, reichert@numachi.com
#
      $buf .= ' ' . $_;
      $buf =~ s/\s+/ /g;

      if ($buf =~ / DEFINITIONS ::= BEGIN/) {
	if ($pass == 0 && $need2pass) {
	  seek(MIB, $pos, 0);
	  $buf = "";
	  $pass = 1;
	  $need2pass = 0;
	  $cnt = 0;
	  next;
	}
	$need2pass = 0;
	$pass = 0;
	$pos = tell(MIB);
	undef %Link;
	undef %prev;
	%Link = (
	  'org' => 'iso',
	  'dod' => 'org',
	  'internet' => 'dod',
	  'directory' => 'internet',
	  'mgmt' => 'internet',
	  'mib-2' => 'mgmt',
	  'experimental' => 'internet',
	  'private' => 'internet',
	  'enterprises' => 'private',
	);
	$buf = "";
	next;
      }

      $buf =~ s/OBJECT-TYPE/OBJECT IDENTIFIER/;
      $buf =~ s/OBJECT-IDENTITY/OBJECT IDENTIFIER/;
      $buf =~ s/OBJECT-GROUP/OBJECT IDENTIFIER/;
      $buf =~ s/MODULE-IDENTITY/OBJECT IDENTIFIER/;
      $buf =~ s/ IMPORTS .*\;//;
      $buf =~ s/ SEQUENCE {.*}//;
      $buf =~ s/ SYNTAX .*//;
      $buf =~ s/ [\w-]+ ::= OBJECT IDENTIFIER//;
      $buf =~ s/ OBJECT IDENTIFIER .* ::= {/ OBJECT IDENTIFIER ::= {/;
      $buf =~ s/".*"//;
      if ($buf =~ /"/) {
	$quote = 1;
      }

      if ($buf =~ / ([\w\-]+) OBJECT IDENTIFIER ::= {([^}]+)}/) {
	$var = $1;
	$buf = $2;
	undef $val;
	$buf =~ s/ +$//;
	($code, $val) = split(' ', $buf, 2);

	if (!defined($val) || (length($val) <= 0)) {
	  $SNMP_util::OIDS{$var} = $code;
	  $cnt++;
	  print "'$var' => '$code'\n" if $SNMP_util::Debug;
	} else {
	  $strt = $code;
	  while($val =~ / /) {
	    ($tmp, $val) = split(' ', $val, 2);
	    if ($tmp =~ /([\w\-]+)\((\d+)\)/) {
	      $tmp = $1;
	      $tmpv = "$SNMP_util::OIDS{$strt}.$2";
	      $Link{$tmp} = $strt;
	      if (!defined($prev{$tmp}) && defined($SNMP_util::OIDS{$tmp})) {
		if ($tmpv ne $SNMP_util::OIDS{$tmp}) {
		  $strt = "$strt.$tmp";
		  $SNMP_util::OIDS{$strt} = $tmpv;
		  $cnt++;
		}
	      } else {
		$prev{$tmp} = 1;
		$SNMP_util::OIDS{$tmp} = $tmpv;
		$cnt++;
		$strt = $tmp;
	      }
	    }
	  }

	  if (!defined($SNMP_util::OIDS{$strt})) {
	    if ($pass) {
	      carp "snmpMIB_to_OID: $arg: \"$strt\" prefix unknown, load the parent MIB first.\n"
		unless ($SNMP_Session::suppress_warnings > 1);
	    } else {
		$need2pass = 1;
	    }
	  }
	  $Link{$var} = $strt;
	  $val = "$SNMP_util::OIDS{$strt}.$val";
	  if (!defined($prev{$var}) && defined($SNMP_util::OIDS{$var})) {
	    if ($val ne $SNMP_util::OIDS{$var}) {
	      $var = "$strt.$var";
	    }
	  }

	  $SNMP_util::OIDS{$var} = $val;
	  $prev{$var} = 1;
	  $cnt++;

	  print "'$var' => '$val'\n" if $SNMP_util::Debug;
	}
	undef $buf;
      }
    }
    if ($pass == 0 && $need2pass) {
      seek(MIB, $pos, 0);
      $buf = "";
      $pass = 1;
      $cnt = 0;
    } else {
      $ret += $cnt;
      $need2pass = 0;
    }
  }
  close(MIB);
  $RevNeeded = 1;
  return $ret;
}

sub encode_oid_with_errmsg ($) {
  my ($oid) = @_;
  my $tmp = encode_oid(split(/\./, $oid));
  if (! defined $tmp) {
    carp "cannot encode Object ID $oid: $BER::errmsg"
      unless ($SNMP_Session::suppress_warnings > 1);
    return undef;
  }
  return $tmp;
}

1;
