I've got the snmp side working on the yun. I've managed to install pysnmp en can now perform a get on a python snmp agent. Now the next step is to merge below code with the Yun bridge and you have a working solution. Good luck.
To install pysnmp, please follow the steps on http://tavendo.com/blog/post/arduino-yun-with-autobahn/ untill the "twisted" part. And then download and install pysnmp.
For these instructions you need a SD card for the Yun.
Then you can run the following code:
Agent python code:
from pysnmp.carrier.asynsock.dispatch import AsynsockDispatcher
from pysnmp.carrier.asynsock.dgram import udp, udp6
from pyasn1.codec.ber import encoder, decoder
from pysnmp.proto import api
import time, bisect
class SysDescr:
name = (1,3,6,1,2,1,1,1,0)
def __eq__(self, other): return self.name == other
def __ne__(self, other): return self.name != other
def __lt__(self, other): return self.name < other
def __le__(self, other): return self.name <= other
def __gt__(self, other): return self.name > other
def __ge__(self, other): return self.name >= other
def __call__(self, protoVer):
return api.protoModules[protoVer].OctetString(
'Yun PySNMP example command responder'
)
class Uptime:
name = (1,3,6,1,2,1,1,3,0)
birthday = time.time()
def __eq__(self, other): return self.name == other
def __ne__(self, other): return self.name != other
def __lt__(self, other): return self.name < other
def __le__(self, other): return self.name <= other
def __gt__(self, other): return self.name > other
def __ge__(self, other): return self.name >= other
def __call__(self, protoVer):
return api.protoModules[protoVer].TimeTicks(
(time.time()-self.birthday)*100
)
mibInstr = (
SysDescr(), Uptime() # sorted by object name
)
mibInstrIdx = {}
for mibVar in mibInstr:
mibInstrIdx[mibVar.name] = mibVar
def cbFun(transportDispatcher, transportDomain, transportAddress, wholeMsg):
while wholeMsg:
msgVer = api.decodeMessageVersion(wholeMsg)
if msgVer in api.protoModules:
pMod = api.protoModules[msgVer]
else:
print('Unsupported SNMP version %s' % msgVer)
return
reqMsg, wholeMsg = decoder.decode(
wholeMsg, asn1Spec=pMod.Message(),
)
rspMsg = pMod.apiMessage.getResponse(reqMsg)
rspPDU = pMod.apiMessage.getPDU(rspMsg)
reqPDU = pMod.apiMessage.getPDU(reqMsg)
varBinds = []; pendingErrors = []
errorIndex = 0
# GETNEXT PDU
if reqPDU.isSameTypeWith(pMod.GetNextRequestPDU()):
# Produce response var-binds
for oid, val in pMod.apiPDU.getVarBinds(reqPDU):
errorIndex = errorIndex + 1
# Search next OID to report
nextIdx = bisect.bisect(mibInstr, oid)
if nextIdx == len(mibInstr):
# Out of MIB
varBinds.append((oid, val))
pendingErrors.append(
(pMod.apiPDU.setEndOfMibError, errorIndex)
)
else:
# Report value if OID is found
varBinds.append(
(mibInstr[nextIdx].name, mibInstr[nextIdx](msgVer))
)
elif reqPDU.isSameTypeWith(pMod.GetRequestPDU()):
for oid, val in pMod.apiPDU.getVarBinds(reqPDU):
if oid in mibInstrIdx:
varBinds.append((oid, mibInstrIdx[oid](msgVer)))
else:
# No such instance
varBinds.append((oid, val))
pendingErrors.append(
(pMod.apiPDU.setNoSuchInstanceError, errorIndex)
)
break
else:
# Report unsupported request type
pMod.apiPDU.setErrorStatus(rspPDU, 'genErr')
pMod.apiPDU.setVarBinds(rspPDU, varBinds)
# Commit possible error indices to response PDU
for f, i in pendingErrors:
f(rspPDU, i)
transportDispatcher.sendMessage(
encoder.encode(rspMsg), transportDomain, transportAddress
)
return wholeMsg
transportDispatcher = AsynsockDispatcher()
transportDispatcher.registerRecvCbFun(cbFun)
# UDP/IPv4
transportDispatcher.registerTransport(
udp.domainName, udp.UdpSocketTransport().openServerMode(('localhost', 161))
)
transportDispatcher.jobStarted(1)
try:
# Dispatcher will never finish as job#1 never reaches zero
transportDispatcher.runDispatcher()
except:
transportDispatcher.closeDispatcher()
raise
SNMP get code:
from pysnmp.carrier.asynsock.dispatch import AsynsockDispatcher
from pysnmp.carrier.asynsock.dgram import udp, udp6
from pyasn1.codec.ber import encoder, decoder
from pysnmp.proto import api
from time import time
# 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()
def cbTimerFun(timeNow):
if timeNow - startedAt > 3:
raise Exception("Request timed out")
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)
# UDP/IPv4
transportDispatcher.registerTransport(
udp.domainName, udp.UdpSocketTransport().openClientMode()
)
# Pass message to dispatcher
transportDispatcher.sendMessage(
encoder.encode(reqMsg), udp.domainName, ('127.0.0.1', 161)
)
transportDispatcher.jobStarted(1)
# Dispatcher will finish as job#1 counter reaches zero
transportDispatcher.runDispatcher()
transportDispatcher.closeDispatcher()
