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from pysnmp.carrier.asynsock.dispatch import AsynsockDispatcher
from pysnmp.carrier.asynsock.dgram import udp
from pysnmp.proto import api
from pyasn1.codec.ber import encoder, decoder
from time import time
# Send request message to this address
transportAddress = udp.UdpTransportAddress(('195.218.195.228', 161))
# Send request message from this non-local (!) IP address
transportAddress.setLocalAddress(('1.2.3.4', 0))
# Protocol version to use
#pMod = api.protoModules[api.protoVersion1]
pMod = api.protoModules[api.protoVersion2c]
# Build PDU
reqPDU = pMod.GetRequestPDU()
pMod.apiPDU.setDefaults(reqPDU)
pMod.apiPDU.setVarBinds(
reqPDU, ( ('1.3.6.1.2.1.1.1.0', pMod.Null('')),
('1.3.6.1.2.1.1.3.0', pMod.Null('')) )
)
# Build message
reqMsg = pMod.Message()
pMod.apiMessage.setDefaults(reqMsg)
pMod.apiMessage.setCommunity(reqMsg, 'public')
pMod.apiMessage.setPDU(reqMsg, reqPDU)
startedAt = time()
class StopWaiting(Exception): pass
def cbTimerFun(timeNow):
if timeNow - startedAt > 3:
raise StopWaiting()
def cbRecvFun(transportDispatcher, transportDomain, transportAddress,
wholeMsg, reqPDU=reqPDU):
while wholeMsg:
rspMsg, wholeMsg = decoder.decode(wholeMsg, asn1Spec=pMod.Message())
rspPDU = pMod.apiMessage.getPDU(rspMsg)
# Match response to request
if pMod.apiPDU.getRequestID(reqPDU)==pMod.apiPDU.getRequestID(rspPDU):
# Check for SNMP errors reported
errorStatus = pMod.apiPDU.getErrorStatus(rspPDU)
if errorStatus:
print(errorStatus.prettyPrint())
else:
for oid, val in pMod.apiPDU.getVarBinds(rspPDU):
print('%s = %s' % (oid.prettyPrint(), val.prettyPrint()))
transportDispatcher.jobFinished(1)
return wholeMsg
transportDispatcher = AsynsockDispatcher()
transportDispatcher.registerRecvCbFun(cbRecvFun)
transportDispatcher.registerTimerCbFun(cbTimerFun)
# Initialize UDP/IPv4 transport
udpSocketTransport = udp.UdpSocketTransport().openClientMode()
# Use sendmsg()/recvmsg() for socket communication (required for
# IP source spoofing functionality)
udpSocketTransport.enablePktInfo()
# Enable IP source spoofing (requires root privileges)
udpSocketTransport.enableTransparent()
transportDispatcher.registerTransport(udp.domainName, udpSocketTransport)
# Pass message to dispatcher
transportDispatcher.sendMessage(
encoder.encode(reqMsg), udp.domainName, transportAddress
)
# We might never receive any response as we sent request with fake source IP
transportDispatcher.jobStarted(1)
# Dispatcher will finish as all jobs counter reaches zero
try:
transportDispatcher.runDispatcher()
except StopWaiting:
transportDispatcher.closeDispatcher()
else:
raise
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