/usr/lib/python3/dist-packages/pysnmp/proto/mpmod/rfc2576.py is in python3-pysnmp4 4.2.5-1.
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import sys
from pyasn1.codec.ber import decoder
from pyasn1.type import univ
from pyasn1.compat.octets import null
from pyasn1.error import PyAsn1Error
from pysnmp.proto.mpmod.base import AbstractMessageProcessingModel
from pysnmp.proto import rfc3411, errind, error
from pysnmp.proto.api import v1, v2c
from pysnmp import debug
# Since I have not found a detailed reference to v1MP/v2cMP
# inner workings, the following has been patterned from v3MP. Most
# references here goes to RFC3412.
class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
messageProcessingModelID = univ.Integer(0) # SNMPv1
snmpMsgSpec = v1.Message
# rfc3412: 7.1
def prepareOutgoingMessage(
self,
snmpEngine,
transportDomain,
transportAddress,
messageProcessingModel,
securityModel,
securityName,
securityLevel,
contextEngineId,
contextName,
pduVersion,
pdu,
expectResponse,
sendPduHandle
):
snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
snmpEngineID = snmpEngineID.syntax
# rfc3412: 7.1.1b
if pdu.tagSet in rfc3411.confirmedClassPDUs:
pdu.setComponentByPosition(1)
msgID = pdu.getComponentByPosition(0)
# rfc3412: 7.1.4
# Since there's no SNMP engine identification in v1/2c,
# set destination contextEngineId to ours
if not contextEngineId:
contextEngineId = snmpEngineID
# rfc3412: 7.1.5
if not contextName:
contextName = null
debug.logger & debug.flagMP and debug.logger('prepareOutgoingMessage: using contextEngineId %r contextName %r' % (contextEngineId, contextName))
# rfc3412: 7.1.6
scopedPDU = ( contextEngineId, contextName, pdu )
msg = self._snmpMsgSpec
msg.setComponentByPosition(0, self.messageProcessingModelID)
msg.setComponentByPosition(2)
msg.getComponentByPosition(2).setComponentByType(
pdu.tagSet, pdu, verifyConstraints=False
)
# rfc3412: 7.1.7
globalData = ( msg, )
k = int(securityModel)
if k in snmpEngine.securityModels:
smHandler = snmpEngine.securityModels[k]
else:
raise error.StatusInformation(
errorIndication = errind.unsupportedSecurityModel
)
# rfc3412: 7.1.9.a & rfc2576: 5.2.1 --> no-op
snmpEngineMaxMessageSize, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
# rfc3412: 7.1.9.b
( securityParameters,
wholeMsg ) = smHandler.generateRequestMsg(
snmpEngine,
self.messageProcessingModelID,
globalData,
snmpEngineMaxMessageSize.syntax,
securityModel,
snmpEngineID,
securityName,
securityLevel,
scopedPDU
)
# rfc3412: 7.1.9.c
if pdu.tagSet in rfc3411.confirmedClassPDUs:
# XXX rfc bug? why stateReference should be created?
self._cache.pushByMsgId(
int(msgID),
sendPduHandle=sendPduHandle,
msgID=msgID,
snmpEngineID=snmpEngineID,
securityModel=securityModel,
securityName=securityName,
securityLevel=securityLevel,
contextEngineId=contextEngineId,
contextName=contextName,
transportDomain=transportDomain,
transportAddress=transportAddress
)
return ( transportDomain, transportAddress, wholeMsg )
# rfc3412: 7.1
def prepareResponseMessage(
self,
snmpEngine,
messageProcessingModel,
securityModel,
securityName,
securityLevel,
contextEngineId,
contextName,
pduVersion,
pdu,
maxSizeResponseScopedPDU,
stateReference,
statusInformation
):
snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
snmpEngineID = snmpEngineID.syntax
# rfc3412: 7.1.2.b
if stateReference is None:
raise error.StatusInformation(
errorIndication = errind.nonReportable
)
cachedParams = self._cache.popByStateRef(stateReference)
msgID = cachedParams['msgID']
contextEngineId = cachedParams['contextEngineId']
contextName = cachedParams['contextName']
securityModel = cachedParams['securityModel']
securityName = cachedParams['securityName']
securityLevel = cachedParams['securityLevel']
securityStateReference = cachedParams['securityStateReference']
maxMessageSize = cachedParams['msgMaxSize']
transportDomain = cachedParams['transportDomain']
transportAddress = cachedParams['transportAddress']
debug.logger & debug.flagMP and debug.logger('prepareResponseMessage: cache read msgID %s transportDomain %s transportAddress %s by stateReference %s' % (msgID, transportDomain, transportAddress, stateReference))
# rfc3412: 7.1.3
if statusInformation:
# rfc3412: 7.1.3a (N/A)
# rfc3412: 7.1.3b (always discard)
raise error.StatusInformation(
errorIndication = errind.nonReportable
)
# rfc3412: 7.1.4
# Since there's no SNMP engine identification in v1/2c,
# set destination contextEngineId to ours
if not contextEngineId:
contextEngineId = snmpEngineID
# rfc3412: 7.1.5
if not contextName:
contextName = null
# rfc3412: 7.1.6
scopedPDU = ( contextEngineId, contextName, pdu )
debug.logger & debug.flagMP and debug.logger('prepareResponseMessage: using contextEngineId %r contextName %r' % (contextEngineId, contextName))
msg = self._snmpMsgSpec
msg.setComponentByPosition(0, messageProcessingModel)
msg.setComponentByPosition(2)
msg.getComponentByPosition(2).setComponentByType(
pdu.tagSet, pdu, verifyConstraints=False
)
# att: msgId not set back to PDU as it's up to responder app
# rfc3412: 7.1.7
globalData = ( msg, )
k = int(securityModel)
if k in snmpEngine.securityModels:
smHandler = snmpEngine.securityModels[k]
else:
raise error.StatusInformation(
errorIndication = errind.unsupportedSecurityModel
)
securityEngineId = snmpEngineID
# rfc3412: 7.1.8.a
( securityParameters,
wholeMsg ) = smHandler.generateResponseMsg(
snmpEngine,
self.messageProcessingModelID,
globalData,
maxMessageSize,
securityModel,
snmpEngineID,
securityName,
securityLevel,
scopedPDU,
securityStateReference
)
return ( transportDomain, transportAddress, wholeMsg )
# rfc3412: 7.2.1
def prepareDataElements(
self,
snmpEngine,
transportDomain,
transportAddress,
wholeMsg
):
# rfc3412: 7.2.2
try:
msg, restOfwholeMsg = decoder.decode(
wholeMsg, asn1Spec=self._snmpMsgSpec
)
except PyAsn1Error:
debug.logger & debug.flagMP and debug.logger('prepareDataElements: %s' % (sys.exc_info()[1],))
snmpInASNParseErrs, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpInASNParseErrs')
snmpInASNParseErrs.syntax = snmpInASNParseErrs.syntax + 1
raise error.StatusInformation(
errorIndication = errind.parseError
)
debug.logger & debug.flagMP and debug.logger('prepareDataElements: %s' % (msg.prettyPrint(),))
# rfc3412: 7.2.3
msgVersion = messageProcessingModel = msg.getComponentByPosition(0)
# rfc2576: 5.2.1
snmpEngineMaxMessageSize, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
securityParameters = (
msg.getComponentByPosition(1),
# transportDomain identifies local enpoint
(transportDomain, transportAddress)
)
messageProcessingModel = int(msg.getComponentByPosition(0))
securityModel = messageProcessingModel + 1
securityLevel = 1
# rfc3412: 7.2.4 -- 7.2.5 -> noop
k = int(securityModel)
if k in snmpEngine.securityModels:
smHandler = snmpEngine.securityModels[k]
else:
raise error.StatusInformation(
errorIndication = errind.unsupportedSecurityModel
)
# rfc3412: 7.2.6
( securityEngineID,
securityName,
scopedPDU,
maxSizeResponseScopedPDU,
securityStateReference ) = smHandler.processIncomingMsg(
snmpEngine,
messageProcessingModel,
snmpEngineMaxMessageSize.syntax,
securityParameters,
securityModel,
securityLevel,
wholeMsg,
msg
)
debug.logger & debug.flagMP and debug.logger('prepareDataElements: SM returned securityEngineID %r securityName %r' % (securityEngineID, securityName))
# rfc3412: 7.2.6a --> noop
# rfc3412: 7.2.7
contextEngineId, contextName, pdu = scopedPDU
# rfc2576: 5.2.1
pduVersion = msgVersion
pduType = pdu.tagSet
# rfc3412: 7.2.8, 7.2.9 -> noop
# rfc3412: 7.2.10
if pduType in rfc3411.responseClassPDUs:
# (wild hack: use PDU reqID at MsgID)
msgID = pdu.getComponentByPosition(0)
# 7.2.10a
try:
cachedReqParams = self._cache.popByMsgId(int(msgID))
except error.ProtocolError:
smHandler.releaseStateInformation(securityStateReference)
raise error.StatusInformation(
errorIndication = errind.dataMismatch
)
# 7.2.10b
sendPduHandle = cachedReqParams['sendPduHandle']
else:
sendPduHandle = None
# no error by default
statusInformation = None
# rfc3412: 7.2.11 -> noop
# rfc3412: 7.2.12
if pduType in rfc3411.responseClassPDUs:
# rfc3412: 7.2.12a -> noop
# rfc3412: 7.2.12b
if securityModel != cachedReqParams['securityModel'] or \
securityName != cachedReqParams['securityName'] or \
securityLevel != cachedReqParams['securityLevel'] or \
contextEngineId != cachedReqParams['contextEngineId'] or \
contextName != cachedReqParams['contextName']:
smHandler.releaseStateInformation(securityStateReference)
raise error.StatusInformation(
errorIndication = errind.dataMismatch
)
stateReference = None
# rfc3412: 7.2.12c
smHandler.releaseStateInformation(securityStateReference)
# rfc3412: 7.2.12d
return ( messageProcessingModel,
securityModel,
securityName,
securityLevel,
contextEngineId,
contextName,
pduVersion,
pdu,
pduType,
sendPduHandle,
maxSizeResponseScopedPDU,
statusInformation,
stateReference )
# rfc3412: 7.2.13
if pduType in rfc3411.confirmedClassPDUs:
# (wild hack: use PDU reqID at MsgID)
msgID = pdu.getComponentByPosition(0)
# rfc3412: 7.2.13a
snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
if securityEngineID != snmpEngineID.syntax:
smHandler.releaseStateInformation(securityStateReference)
raise error.StatusInformation(
errorIndication = errind.engineIDMismatch
)
# rfc3412: 7.2.13b
stateReference = self._cache.newStateReference()
self._cache.pushByStateRef(
stateReference,
msgVersion=messageProcessingModel,
msgID=msgID,
contextEngineId=contextEngineId,
contextName=contextName,
securityModel=securityModel,
securityName=securityName,
securityLevel=securityLevel,
securityStateReference=securityStateReference,
msgMaxSize=snmpEngineMaxMessageSize.syntax,
maxSizeResponseScopedPDU=maxSizeResponseScopedPDU,
transportDomain=transportDomain,
transportAddress=transportAddress
)
debug.logger & debug.flagMP and debug.logger('prepareDataElements: cached by new stateReference %s' % stateReference)
# rfc3412: 7.2.13c
return ( messageProcessingModel,
securityModel,
securityName,
securityLevel,
contextEngineId,
contextName,
pduVersion,
pdu,
pduType,
sendPduHandle,
maxSizeResponseScopedPDU,
statusInformation,
stateReference )
# rfc3412: 7.2.14
if pduType in rfc3411.unconfirmedClassPDUs:
# Pass new stateReference to let app browse request details
stateReference = self._cache.newStateReference()
# This is not specified explicitly in RFC
smHandler.releaseStateInformation(securityStateReference)
return ( messageProcessingModel,
securityModel,
securityName,
securityLevel,
contextEngineId,
contextName,
pduVersion,
pdu,
pduType,
sendPduHandle,
maxSizeResponseScopedPDU,
statusInformation,
stateReference )
smHandler.releaseStateInformation(securityStateReference)
raise error.StatusInformation(
errorIndication = errind.unsupportedPDUtype
)
class SnmpV2cMessageProcessingModel(SnmpV1MessageProcessingModel):
messageProcessingModelID = univ.Integer(1) # SNMPv2c
snmpMsgSpec = v2c.Message
|