145 lines
4.1 KiB
Python
145 lines
4.1 KiB
Python
"""
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SNMPv3-to-SNMPv2c conversion
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++++++++++++++++++++++++++++
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Act as a local SNMPv3 Agent, relay messages to distant SNMPv1/v2c Agent:
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* over IPv4/UDP
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* with local SNMPv3 user usr-md5-des, MD5 auth and DES privacy protocols
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* local Agent listening at 127.0.0.1:161
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* remote SNMPv1, community public
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* remote Agent listening at 104.236.166.95:161
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This script can be queried with the following Net-SNMP command:
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| $ snmpget -v3 -l authPriv -u usr-md5-des -A authkey1 -X privkey1 -ObentU 127.0.0.1:161 1.3.6.1.2.1.1.1.0
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due to proxy, it is equivalent to
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| $ snmpget -v2c -c public 104.236.166.95:161 1.3.6.1.2.1.1.1.0
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Warning: for production operation you would need to modify this script
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so that it will re-map possible duplicate request-ID values, coming in
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initial request PDUs from different Managers, into unique values to
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avoid sending duplicate request-IDs to Agents.
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"""#
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from pysnmp.carrier.asyncore.dgram import udp
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from pysnmp.entity import engine, config
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from pysnmp.entity.rfc3413 import cmdrsp, cmdgen, context
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from pysnmp.proto.api import v2c
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from pysnmp import error
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# Create SNMP engine with autogenernated engineID and pre-bound
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# to socket transport dispatcher
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snmpEngine = engine.SnmpEngine()
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#
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# Transport setup
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#
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# Agent section
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# UDP over IPv4
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config.addTransport(
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snmpEngine,
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udp.domainName + (1,),
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udp.UdpTransport().openServerMode(('127.0.0.1', 161))
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)
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# Manager section
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# UDP over IPv4
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config.addTransport(
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snmpEngine,
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udp.domainName + (2,),
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udp.UdpTransport().openClientMode()
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)
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#
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# SNMPv3/USM setup (Agent role)
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#
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# user: usr-md5-des, auth: MD5, priv DES
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config.addV3User(
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snmpEngine, 'usr-md5-des',
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config.usmHMACMD5AuthProtocol, 'authkey1',
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config.usmDESPrivProtocol, 'privkey1'
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)
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#
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# SNMPv1/2c setup (Manager role)
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#
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# SecurityName <-> CommunityName mapping
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config.addV1System(snmpEngine, 'my-area', 'public')
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#
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# Transport target used by Manager
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#
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# Specify security settings per SecurityName (SNMPv1 - 0, SNMPv2c - 1)
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config.addTargetParams(snmpEngine, 'distant-agent-auth', 'my-area',
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'noAuthNoPriv', 0)
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config.addTargetAddr(
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snmpEngine, 'distant-agent',
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udp.domainName + (2,), ('104.236.166.95', 161),
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'distant-agent-auth', retryCount=0
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)
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# Default SNMP context
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config.addContext(snmpEngine, '')
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class CommandResponder(cmdrsp.CommandResponderBase):
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cmdGenMap = {
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v2c.GetRequestPDU.tagSet: cmdgen.GetCommandGenerator(),
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v2c.SetRequestPDU.tagSet: cmdgen.SetCommandGenerator(),
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v2c.GetNextRequestPDU.tagSet: cmdgen.NextCommandGeneratorSingleRun(),
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v2c.GetBulkRequestPDU.tagSet: cmdgen.BulkCommandGeneratorSingleRun()
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}
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SUPPORTED_PDU_TYPES = cmdGenMap.keys() # This app will handle these PDUs
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# SNMP request relay
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def handleMgmtOperation(self, snmpEngine, stateReference, contextName,
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PDU, acInfo):
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cbCtx = stateReference, PDU
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contextEngineId = None # address authoritative SNMP Engine
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try:
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self.cmdGenMap[PDU.tagSet].sendPdu(
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snmpEngine, 'distant-agent',
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contextEngineId, contextName,
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PDU,
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self.handleResponsePdu, cbCtx
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)
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except error.PySnmpError:
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self.handleResponsePdu(
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snmpEngine, stateReference, 'error', None, cbCtx
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)
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# SNMP response relay
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# noinspection PyUnusedLocal
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def handleResponsePdu(self, snmpEngine, sendRequestHandle,
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errorIndication, PDU, cbCtx):
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stateReference, reqPDU = cbCtx
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if errorIndication:
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PDU = v2c.apiPDU.getResponse(reqPDU)
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PDU.setErrorStatus(PDU, 5)
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self.sendPdu(snmpEngine, stateReference, PDU)
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self.releaseStateInformation(stateReference)
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CommandResponder(snmpEngine, context.SnmpContext(snmpEngine))
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snmpEngine.transportDispatcher.jobStarted(1) # this job would never finish
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# Run I/O dispatcher which would receive queries and send responses
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try:
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snmpEngine.transportDispatcher.runDispatcher()
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except:
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snmpEngine.transportDispatcher.closeDispatcher()
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raise
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