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#
# GETNEXT Command Generator
#
# Send a series of SNMP GETNEXT requests
# with SNMPv3 with user 'usr-none-none', no auth and no privacy protocols
# over IPv4/UDP
# using Twisted framework for network transport
# to an Agent at 195.218.195.228:161
# for an OID in string form
# stop whenever received OID goes out of initial prefix (it may be a table)
#
# This script performs similar to the following Net-SNMP command:
#
# $ snmpwalk -v3 -l noAuthNoPriv -u usr-none-none -ObentU 195.218.195.228:161 1.3.6.1.2.1.1
#
from twisted.internet import reactor, defer
from pysnmp.entity import engine, config
from pysnmp.entity.rfc3413.twisted import cmdgen
from pysnmp.proto import rfc1902, rfc1905
from pysnmp.carrier.twisted.dgram import udp
# Initial OID prefix
initialOID = rfc1902.ObjectName('1.3.6.1.2.1.1')
# Create SNMP engine instance
snmpEngine = engine.SnmpEngine()
#
# SNMPv3/USM setup
#
# user: usr-none-none, no auth, no priv
config.addV3User(
snmpEngine, 'usr-none-none',
)
config.addTargetParams(snmpEngine, 'my-creds', 'usr-none-none', 'noAuthNoPriv')
#
# Setup transport endpoint and bind it with security settings yielding
# a target name
#
# UDP/IPv4
config.addTransport(
snmpEngine,
udp.domainName,
udp.UdpTwistedTransport().openClientMode()
)
config.addTargetAddr(
snmpEngine, 'my-router',
udp.domainName, ('195.218.195.228', 161),
'my-creds'
)
# Error/response receiver
def cbFun(response, *args):
snmpEngine, errorIndication, errorStatus, errorIndex, varBindTable = response
if errorIndication:
print(errorIndication)
elif errorStatus:
print('%s at %s' % (
errorStatus.prettyPrint(),
errorIndex and varBinds[int(errorIndex)-1][0] or '?'
)
)
else:
for varBindRow in varBindTable:
for oid, val in varBindRow:
if initialOID.isPrefixOf(oid):
print('%s = %s' % (oid.prettyPrint(), val.prettyPrint()))
else:
reactor.stop()
return False # signal dispatcher to stop
# Stop reactor when we are done walking (optional)
for oid, val in varBindRow:
if not val.isSameTypeWith(rfc1905.endOfMibView):
break
else:
reactor.stop()
return
# Re-create deferred for next GETNEXT iteration
df = defer.Deferred()
df.addCallback(cbFun)
return df # This also indicates that we wish to continue walking
# Stop reactor on SNMP error (optional)
reactor.stop()
# Prepare request to be sent yielding Twisted deferred object
df = cmdgen.NextCommandGenerator().sendVarBinds(
snmpEngine,
'my-router',
None, '', # contextEngineId, contextName
[ (initialOID, None) ]
)
# Register error/response receiver function at deferred
df.addCallback(cbFun)
# Run Twisted main loop
reactor.run()
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