def main():
class CommandResponder(cmdrsp.CommandResponderBase):
pduTypes = (rfc1905.SetRequestPDU.tagSet, rfc1905.GetRequestPDU.tagSet,
rfc1905.GetNextRequestPDU.tagSet,
rfc1905.GetBulkRequestPDU.tagSet)
def handleMgmtOperation(self, snmpEngine, stateReference, contextName,
pdu, acInfo):
trunkReq = gCurrentRequestContext.copy()
trunkReq['snmp-pdu'] = pdu
pluginIdList = trunkReq['plugins-list']
logCtx = LogString(trunkReq)
reqCtx = {}
for pluginNum, pluginId in enumerate(pluginIdList):
st, pdu = pluginManager.processCommandRequest(
pluginId, snmpEngine, pdu, trunkReq, reqCtx)
if st == status.BREAK:
log.debug('plugin %s inhibits other plugins' % pluginId,
ctx=logCtx)
pluginIdList = pluginIdList[:pluginNum]
break
elif st == status.DROP:
log.debug(
'received SNMP message, plugin %s muted request' %
pluginId,
ctx=logCtx)
self.releaseStateInformation(stateReference)
return
elif st == status.RESPOND:
log.debug(
'received SNMP message, plugin %s forced immediate response'
% pluginId,
ctx=logCtx)
try:
self.sendPdu(snmpEngine, stateReference, pdu)
except PySnmpError:
log.error('failure sending SNMP response', ctx=logCtx)
else:
self.releaseStateInformation(stateReference)
return
# pass query to trunk
trunkIdList = trunkReq['trunk-id-list']
if trunkIdList is None:
log.error('no route configured', ctx=logCtx)
self.releaseStateInformation(stateReference)
return
for trunkId in trunkIdList:
cbCtx = pluginIdList, trunkId, trunkReq, snmpEngine, stateReference, reqCtx
try:
msgId = trunkingManager.sendReq(trunkId, trunkReq,
self.trunkCbFun, cbCtx)
except SnmpfwdError:
log.error(
'received SNMP message, message not sent to trunk "%s"'
% sys.exc_info()[1],
ctx=logCtx)
return
log.debug(
'received SNMP message, forwarded as trunk message #%s' %
msgId,
ctx=logCtx)
def trunkCbFun(self, msgId, trunkRsp, cbCtx):
pluginIdList, trunkId, trunkReq, snmpEngine, stateReference, reqCtx = cbCtx
for key in tuple(trunkRsp):
if key != 'callflow-id':
trunkRsp['client-' + key] = trunkRsp[key]
del trunkRsp[key]
trunkRsp['callflow-id'] = trunkReq['callflow-id']
logCtx = LogString(trunkRsp)
if trunkRsp['client-error-indication']:
log.info(
'received trunk message #%s, remote end reported error-indication "%s", NOT responding'
% (msgId, trunkRsp['client-error-indication']),
ctx=logCtx)
elif 'client-snmp-pdu' not in trunkRsp:
log.info(
'received trunk message #%s, remote end does not send SNMP PDU, NOT responding'
% msgId,
ctx=logCtx)
else:
pdu = trunkRsp['client-snmp-pdu']
for pluginId in pluginIdList:
st, pdu = pluginManager.processCommandResponse(
pluginId, snmpEngine, pdu, trunkReq, reqCtx)
if st == status.BREAK:
log.debug('plugin %s inhibits other plugins' %
pluginId,
ctx=logCtx)
break
elif st == status.DROP:
log.debug('plugin %s muted response' % pluginId,
ctx=logCtx)
self.releaseStateInformation(stateReference)
return
try:
self.sendPdu(snmpEngine, stateReference, pdu)
except PySnmpError:
log.error('failure sending SNMP response', ctx=logCtx)
else:
log.debug(
'received trunk message #%s, forwarded as SNMP message'
% msgId,
ctx=logCtx)
self.releaseStateInformation(stateReference)
#
# SNMPv3 NotificationReceiver implementation
#
class NotificationReceiver(ntfrcv.NotificationReceiver):
pduTypes = (rfc1157.TrapPDU.tagSet, rfc1905.SNMPv2TrapPDU.tagSet)
def processPdu(self, snmpEngine, messageProcessingModel, securityModel,
securityName, securityLevel, contextEngineId,
contextName, pduVersion, pdu, maxSizeResponseScopedPDU,
stateReference):
trunkReq = gCurrentRequestContext.copy()
if messageProcessingModel == 0:
pdu = rfc2576.v1ToV2(pdu)
# TODO: why this is not automatic?
v2c.apiTrapPDU.setDefaults(pdu)
trunkReq['snmp-pdu'] = pdu
pluginIdList = trunkReq['plugins-list']
logCtx = LogString(trunkReq)
reqCtx = {}
for pluginNum, pluginId in enumerate(pluginIdList):
st, pdu = pluginManager.processNotificationRequest(
pluginId, snmpEngine, pdu, trunkReq, reqCtx)
if st == status.BREAK:
log.debug('plugin %s inhibits other plugins' % pluginId,
ctx=logCtx)
pluginIdList = pluginIdList[:pluginNum]
break
elif st == status.DROP:
log.debug('plugin %s muted request' % pluginId, ctx=logCtx)
return
elif st == status.RESPOND:
log.debug('plugin %s NOT forced immediate response' %
pluginId,
ctx=logCtx)
# TODO: implement immediate response for confirmed-class PDU
return
# pass query to trunk
trunkIdList = trunkReq['trunk-id-list']
if trunkIdList is None:
log.error('no route configured', ctx=logCtx)
return
for trunkId in trunkIdList:
# TODO: pass messageProcessingModel to respond
cbCtx = pluginIdList, trunkId, trunkReq, snmpEngine, stateReference, reqCtx
try:
msgId = trunkingManager.sendReq(trunkId, trunkReq,
self.trunkCbFun, cbCtx)
except SnmpfwdError:
log.error(
'received SNMP message, message not sent to trunk "%s" %s'
% (trunkId, sys.exc_info()[1]),
ctx=logCtx)
return
log.debug(
'received SNMP message, forwarded as trunk message #%s' %
msgId,
ctx=logCtx)
def trunkCbFun(self, msgId, trunkRsp, cbCtx):
pluginIdList, trunkId, trunkReq, snmpEngine, stateReference, reqCtx = cbCtx
for key in tuple(trunkRsp):
if key != 'callflow-id':
trunkRsp['client-' + key] = trunkRsp[key]
del trunkRsp[key]
trunkRsp['callflow-id'] = trunkReq['callflow-id']
logCtx = LazyLogString(trunkReq, trunkRsp)
if trunkRsp['client-error-indication']:
log.info(
'received trunk message #%s, remote end reported error-indication "%s", NOT responding'
% (msgId, trunkRsp['client-error-indication']),
ctx=logCtx)
else:
if 'client-snmp-pdu' not in trunkRsp:
log.debug(
'received trunk message #%s -- unconfirmed SNMP message'
% msgId,
ctx=logCtx)
return
pdu = trunkRsp['client-snmp-pdu']
for pluginId in pluginIdList:
st, pdu = pluginManager.processNotificationResponse(
pluginId, snmpEngine, pdu, trunkReq, reqCtx)
if st == status.BREAK:
log.debug('plugin %s inhibits other plugins' %
pluginId,
ctx=logCtx)
break
elif st == status.DROP:
log.debug(
'received trunk message #%s, plugin %s muted response'
% (msgId, pluginId),
ctx=logCtx)
return
log.debug(
'received trunk message #%s, forwarded as SNMP message' %
msgId,
ctx=logCtx)
# TODO: implement response part
# # Agent-side API complies with SMIv2
# if messageProcessingModel == 0:
# PDU = rfc2576.v2ToV1(PDU, origPdu)
#
# statusInformation = {}
#
# # 3.4.3
# try:
# snmpEngine.msgAndPduDsp.returnResponsePdu(
# snmpEngine, messageProcessingModel, securityModel,
# securityName, securityLevel, contextEngineId,
# contextName, pduVersion, rspPDU, maxSizeResponseScopedPDU,
# stateReference, statusInformation)
#
# except error.StatusInformation:
# log.error('processPdu: stateReference %s, statusInformation %s' % (stateReference, sys.exc_info()[1]))
class LogString(LazyLogString):
GROUPINGS = [
['callflow-id'],
[
'snmp-engine-id', 'snmp-transport-domain', 'snmp-bind-address',
'snmp-bind-port', 'snmp-security-model', 'snmp-security-level',
'snmp-security-name', 'snmp-credentials-id'
],
['snmp-context-engine-id', 'snmp-context-name', 'snmp-context-id'],
['snmp-pdu', 'snmp-content-id'],
['snmp-peer-address', 'snmp-peer-port', 'snmp-peer-id'],
['trunk-id'],
['client-snmp-pdu'],
]
FORMATTERS = {
'client-snmp-pdu': LazyLogString.prettyVarBinds,
'snmp-pdu': LazyLogString.prettyVarBinds,
}
def securityAuditObserver(snmpEngine, execpoint, variables, cbCtx):
securityModel = variables.get('securityModel', 0)
logMsg = 'SNMPv%s auth failure' % securityModel
logMsg += ' at %s:%s' % variables['transportAddress'].getLocalAddress()
logMsg += ' from %s:%s' % variables['transportAddress']
statusInformation = variables.get('statusInformation', {})
if securityModel in (1, 2):
logMsg += ' using snmp-community-name "%s"' % statusInformation.get(
'communityName', '?')
elif securityModel == 3:
logMsg += ' using snmp-usm-user "%s"' % statusInformation.get(
'msgUserName', '?')
try:
logMsg += ': %s' % statusInformation['errorIndication']
except KeyError:
pass
log.error(logMsg)
def requestObserver(snmpEngine, execpoint, variables, cbCtx):
trunkReq = {
'callflow-id': '%10.10x' % random.randint(0, 0xffffffffff),
'snmp-engine-id': snmpEngine.snmpEngineID,
'snmp-transport-domain': variables['transportDomain'],
'snmp-peer-address': variables['transportAddress'][0],
'snmp-peer-port': variables['transportAddress'][1],
'snmp-bind-address':
variables['transportAddress'].getLocalAddress()[0],
'snmp-bind-port':
variables['transportAddress'].getLocalAddress()[1],
'snmp-security-model': variables['securityModel'],
'snmp-security-level': variables['securityLevel'],
'snmp-security-name': variables['securityName'],
'snmp-context-engine-id': variables['contextEngineId'],
'snmp-context-name': variables['contextName'],
}
trunkReq['snmp-credentials-id'] = macro.expandMacro(
credIdMap.get(
(str(snmpEngine.snmpEngineID), variables['transportDomain'],
variables['securityModel'], variables['securityLevel'],
str(variables['securityName']))), trunkReq)
k = '#'.join([
str(x)
for x in (variables['contextEngineId'], variables['contextName'])
])
for x, y in contextIdList:
if y.match(k):
trunkReq['snmp-context-id'] = macro.expandMacro(x, trunkReq)
break
else:
trunkReq['snmp-context-id'] = None
addr = '%s:%s#%s:%s' % (
variables['transportAddress'][0], variables['transportAddress'][1],
variables['transportAddress'].getLocalAddress()[0],
variables['transportAddress'].getLocalAddress()[1])
for pat, peerId in peerIdMap.get(str(variables['transportDomain']),
()):
if pat.match(addr):
trunkReq['snmp-peer-id'] = macro.expandMacro(peerId, trunkReq)
break
else:
trunkReq['snmp-peer-id'] = None
pdu = variables['pdu']
if pdu.tagSet == v1.TrapPDU.tagSet:
pdu = rfc2576.v1ToV2(pdu)
v2c.apiTrapPDU.setDefaults(pdu)
k = '#'.join([
snmpPduTypesMap.get(variables['pdu'].tagSet, '?'),
'|'.join([str(x[0]) for x in v2c.apiTrapPDU.getVarBinds(pdu)])
])
for x, y in contentIdList:
if y.match(k):
trunkReq['snmp-content-id'] = macro.expandMacro(x, trunkReq)
break
else:
trunkReq['snmp-content-id'] = None
trunkReq['plugins-list'] = pluginIdMap.get(
(trunkReq['snmp-credentials-id'], trunkReq['snmp-context-id'],
trunkReq['snmp-peer-id'], trunkReq['snmp-content-id']), [])
trunkReq['trunk-id-list'] = trunkIdMap.get(
(trunkReq['snmp-credentials-id'], trunkReq['snmp-context-id'],
trunkReq['snmp-peer-id'], trunkReq['snmp-content-id']))
cbCtx.clear()
cbCtx.update(trunkReq)
#
# main script starts here
#
helpMessage = """\
Usage: %s [--help]
[--version ]
[--debug-snmp=<%s>]
[--debug-asn1=<%s>]
[--daemonize]
[--process-user=<uname>] [--process-group=<gname>]
[--pid-file=<file>]
[--logging-method=<%s[:args>]>]
[--log-level=<%s>]
[--config-file=<file>]""" % (sys.argv[0], '|'.join([
x for x in pysnmp_debug.flagMap.keys() if x != 'mibview'
]), '|'.join([x for x in pyasn1_debug.flagMap.keys()]), '|'.join(
log.methodsMap.keys()), '|'.join(log.levelsMap))
try:
opts, params = getopt.getopt(sys.argv[1:], 'hv', [
'help', 'version', 'debug=', 'debug-snmp=', 'debug-asn1=',
'daemonize', 'process-user='******'process-group=', 'pid-file=',
'logging-method=', 'log-level=', 'config-file='
])
except Exception:
sys.stderr.write('ERROR: %s\r\n%s\r\n' %
(sys.exc_info()[1], helpMessage))
return
if params:
sys.stderr.write('ERROR: extra arguments supplied %s\r\n%s\r\n' %
(params, helpMessage))
return
pidFile = ''
cfgFile = CONFIG_FILE
foregroundFlag = True
procUser = procGroup = None
loggingMethod = ['stderr']
loggingLevel = None
for opt in opts:
if opt[0] == '-h' or opt[0] == '--help':
sys.stderr.write("""\
Synopsis:
SNMP Proxy Forwarder: server part. Receives SNMP requests at one or many
built-in SNMP Agents and routes them to encrypted trunks established with
Forwarder's Manager part(s) running elsewhere.
Can implement complex routing logic through analyzing parts of SNMP messages
and matching them against proxying rules.
Documentation:
http://snmpfwd.sourceforge.io/
%s
""" % helpMessage)
return
if opt[0] == '-v' or opt[0] == '--version':
import snmpfwd
import pysnmp
import pyasn1
sys.stderr.write("""\
SNMP Proxy Forwarder version %s, written by Ilya Etingof <*****@*****.**>
Using foundation libraries: pysnmp %s, pyasn1 %s.
Python interpreter: %s
Software documentation and support at https://github.com/etingof/snmpfwd
%s
""" % (snmpfwd.__version__, hasattr(pysnmp, '__version__')
and pysnmp.__version__ or 'unknown',
hasattr(pyasn1, '__version__') and pyasn1.__version__
or 'unknown', sys.version, helpMessage))
return
elif opt[0] == '--debug-snmp':
pysnmp_debug.setLogger(
pysnmp_debug.Debug(*opt[1].split(','),
**dict(loggerName=PROGRAM_NAME +
'.pysnmp')))
elif opt[0] == '--debug-asn1':
pyasn1_debug.setLogger(
pyasn1_debug.Debug(*opt[1].split(','),
**dict(loggerName=PROGRAM_NAME +
'.pyasn1')))
elif opt[0] == '--daemonize':
foregroundFlag = False
elif opt[0] == '--process-user':
procUser = opt[1]
elif opt[0] == '--process-group':
procGroup = opt[1]
elif opt[0] == '--pid-file':
pidFile = opt[1]
elif opt[0] == '--logging-method':
loggingMethod = opt[1].split(':')
elif opt[0] == '--log-level':
loggingLevel = opt[1]
elif opt[0] == '--config-file':
cfgFile = opt[1]
try:
log.setLogger(PROGRAM_NAME, *loggingMethod, **dict(force=True))
if loggingLevel:
log.setLevel(loggingLevel)
except SnmpfwdError:
sys.stderr.write('%s\r\n%s\r\n' % (sys.exc_info()[1], helpMessage))
return
try:
cfgTree = cparser.Config().load(cfgFile)
except SnmpfwdError:
log.error('configuration parsing error: %s' % sys.exc_info()[1])
return
if cfgTree.getAttrValue('program-name', '', default=None) != PROGRAM_NAME:
log.error('config file %s does not match program name %s' %
(cfgFile, PROGRAM_NAME))
return
if cfgTree.getAttrValue('config-version', '',
default=None) != CONFIG_VERSION:
log.error(
'config file %s version is not compatible with program version %s'
% (cfgFile, CONFIG_VERSION))
return
random.seed()
gCurrentRequestContext = {}
credIdMap = {}
peerIdMap = {}
contextIdList = []
contentIdList = []
pluginIdMap = {}
trunkIdMap = {}
engineIdMap = {}
transportDispatcher = AsynsockDispatcher()
transportDispatcher.registerRoutingCbFun(lambda td, t, d: td)
transportDispatcher.setSocketMap() # use global asyncore socket map
#
# Initialize plugin modules
#
pluginManager = PluginManager(macro.expandMacros(
cfgTree.getAttrValue('plugin-modules-path-list',
'',
default=[],
vector=True),
{'config-dir': os.path.dirname(cfgFile)}),
progId=PROGRAM_NAME,
apiVer=PLUGIN_API_VERSION)
for pluginCfgPath in cfgTree.getPathsToAttr('plugin-id'):
pluginId = cfgTree.getAttrValue('plugin-id', *pluginCfgPath)
pluginMod = cfgTree.getAttrValue('plugin-module', *pluginCfgPath)
pluginOptions = macro.expandMacros(
cfgTree.getAttrValue('plugin-options', *pluginCfgPath,
**dict(default=[], vector=True)),
{'config-dir': os.path.dirname(cfgFile)})
log.info(
'configuring plugin ID %s (at %s) from module %s with options %s...'
% (pluginId, '.'.join(pluginCfgPath), pluginMod,
', '.join(pluginOptions) or '<none>'))
try:
pluginManager.loadPlugin(pluginId, pluginMod, pluginOptions)
except SnmpfwdError:
log.error('plugin %s not loaded: %s' %
(pluginId, sys.exc_info()[1]))
return
for configEntryPath in cfgTree.getPathsToAttr('snmp-credentials-id'):
credId = cfgTree.getAttrValue('snmp-credentials-id', *configEntryPath)
configKey = []
log.info('configuring snmp-credentials %s (at %s)...' %
(credId, '.'.join(configEntryPath)))
engineId = cfgTree.getAttrValue('snmp-engine-id', *configEntryPath)
if engineId in engineIdMap:
snmpEngine, snmpContext, snmpEngineMap = engineIdMap[engineId]
log.info('using engine-id %s' %
snmpEngine.snmpEngineID.prettyPrint())
else:
snmpEngine = engine.SnmpEngine(snmpEngineID=engineId)
snmpContext = context.SnmpContext(snmpEngine)
snmpEngineMap = {'transportDomain': {}, 'securityName': {}}
snmpEngine.observer.registerObserver(
securityAuditObserver,
'rfc2576.prepareDataElements:sm-failure',
'rfc3412.prepareDataElements:sm-failure',
cbCtx=gCurrentRequestContext)
snmpEngine.observer.registerObserver(
requestObserver,
'rfc3412.receiveMessage:request',
cbCtx=gCurrentRequestContext)
CommandResponder(snmpEngine, snmpContext)
NotificationReceiver(snmpEngine, None)
engineIdMap[engineId] = snmpEngine, snmpContext, snmpEngineMap
log.info('new engine-id %s' %
snmpEngine.snmpEngineID.prettyPrint())
configKey.append(str(snmpEngine.snmpEngineID))
transportDomain = cfgTree.getAttrValue('snmp-transport-domain',
*configEntryPath)
transportDomain = rfc1902.ObjectName(transportDomain)
if transportDomain in snmpEngineMap['transportDomain']:
h, p, transportDomain = snmpEngineMap['transportDomain'][
transportDomain]
log.info('using transport endpoint %s:%s, transport ID %s' %
(h, p, transportDomain))
else:
if transportDomain[:len(udp.domainName)] == udp.domainName:
transport = udp.UdpTransport()
elif transportDomain[:len(udp6.domainName)] == udp6.domainName:
transport = udp6.Udp6Transport()
else:
log.error('unknown transport domain %s' % (transportDomain, ))
return
h, p = cfgTree.getAttrValue('snmp-bind-address',
*configEntryPath).split(':', 1)
snmpEngine.registerTransportDispatcher(transportDispatcher,
transportDomain)
transportOptions = cfgTree.getAttrValue(
'snmp-transport-options', *configEntryPath,
**dict(default=[], vector=True))
t = transport.openServerMode((h, int(p)))
if 'transparent-proxy' in transportOptions:
t.enablePktInfo()
t.enableTransparent()
elif 'virtual-interface' in transportOptions:
t.enablePktInfo()
config.addSocketTransport(snmpEngine, transportDomain, t)
snmpEngineMap['transportDomain'][
transportDomain] = h, p, transportDomain
log.info(
'new transport endpoint %s:%s, options %s, transport ID %s' %
(h, p, transportOptions and '/'.join(transportOptions)
or '<none>', transportDomain))
configKey.append(transportDomain)
securityModel = cfgTree.getAttrValue('snmp-security-model',
*configEntryPath)
securityModel = rfc1902.Integer(securityModel)
securityLevel = cfgTree.getAttrValue('snmp-security-level',
*configEntryPath)
securityLevel = rfc1902.Integer(securityLevel)
securityName = cfgTree.getAttrValue('snmp-security-name',
*configEntryPath)
if securityModel in (1, 2):
if securityName in snmpEngineMap['securityName']:
if snmpEngineMap['securityName'][
securityModel] == securityModel:
log.info('using security-name %s' % securityName)
else:
raise SnmpfwdError(
'snmp-security-name %s already in use at snmp-security-model %s'
% (securityName, securityModel))
else:
communityName = cfgTree.getAttrValue('snmp-community-name',
*configEntryPath)
config.addV1System(snmpEngine,
securityName,
communityName,
securityName=securityName)
log.info(
'new community-name %s, security-model %s, security-name %s, security-level %s'
% (communityName, securityModel, securityName,
securityLevel))
snmpEngineMap['securityName'][securityName] = securityModel
configKey.append(securityModel)
configKey.append(securityLevel)
configKey.append(securityName)
elif securityModel == 3:
if securityName in snmpEngineMap['securityName']:
log.info('using USM security-name: %s' % securityName)
else:
usmUser = cfgTree.getAttrValue('snmp-usm-user',
*configEntryPath)
log.info(
'new USM user %s, security-model %s, security-level %s, security-name %s'
% (usmUser, securityModel, securityLevel, securityName))
if securityLevel in (2, 3):
usmAuthProto = cfgTree.getAttrValue(
'snmp-usm-auth-protocol', *configEntryPath,
**dict(default=config.usmHMACMD5AuthProtocol))
usmAuthProto = rfc1902.ObjectName(usmAuthProto)
usmAuthKey = cfgTree.getAttrValue('snmp-usm-auth-key',
*configEntryPath)
log.info(
'new USM authentication key: %s, authentication protocol: %s'
% (usmAuthKey, usmAuthProto))
if securityLevel == 3:
usmPrivProto = cfgTree.getAttrValue(
'snmp-usm-priv-protocol', *configEntryPath,
**dict(default=config.usmDESPrivProtocol))
usmPrivProto = rfc1902.ObjectName(usmPrivProto)
usmPrivKey = cfgTree.getAttrValue(
'snmp-usm-priv-key', *configEntryPath,
**dict(default=None))
log.info(
'new USM encryption key: %s, encryption protocol: %s'
% (usmPrivKey, usmPrivProto))
config.addV3User(snmpEngine, usmUser, usmAuthProto,
usmAuthKey, usmPrivProto, usmPrivKey)
else:
config.addV3User(snmpEngine, usmUser, usmAuthProto,
usmAuthKey)
else:
config.addV3User(snmpEngine, usmUser)
snmpEngineMap['securityName'][securityName] = securityModel
configKey.append(securityModel)
configKey.append(securityLevel)
configKey.append(securityName)
else:
raise SnmpfwdError('unknown snmp-security-model: %s' %
securityModel)
configKey = tuple(configKey)
if configKey in credIdMap:
log.error(
'ambiguous configuration for key snmp-credentials-id=%s at %s'
% (credId, '.'.join(configEntryPath)))
return
credIdMap[configKey] = credId
duplicates = {}
for peerCfgPath in cfgTree.getPathsToAttr('snmp-peer-id'):
peerId = cfgTree.getAttrValue('snmp-peer-id', *peerCfgPath)
if peerId in duplicates:
log.error(
'duplicate snmp-peer-id=%s at %s and %s' %
(peerId, '.'.join(peerCfgPath), '.'.join(duplicates[peerId])))
return
duplicates[peerId] = peerCfgPath
log.info('configuring peer ID %s (at %s)...' %
(peerId, '.'.join(peerCfgPath)))
transportDomain = cfgTree.getAttrValue('snmp-transport-domain',
*peerCfgPath)
if transportDomain not in peerIdMap:
peerIdMap[transportDomain] = []
for peerAddress in cfgTree.getAttrValue(
'snmp-peer-address-pattern-list', *peerCfgPath,
**dict(vector=True)):
for bindAddress in cfgTree.getAttrValue(
'snmp-bind-address-pattern-list', *peerCfgPath,
**dict(vector=True)):
peerIdMap[transportDomain].append(
(re.compile(peerAddress + '#' + bindAddress), peerId))
duplicates = {}
for contextCfgPath in cfgTree.getPathsToAttr('snmp-context-id'):
contextId = cfgTree.getAttrValue('snmp-context-id', *contextCfgPath)
if contextId in duplicates:
log.error('duplicate snmp-context-id=%s at %s and %s' %
(contextId, '.'.join(contextCfgPath), '.'.join(
duplicates[contextId])))
return
duplicates[contextId] = contextCfgPath
k = '#'.join((cfgTree.getAttrValue('snmp-context-engine-id-pattern',
*contextCfgPath),
cfgTree.getAttrValue('snmp-context-name-pattern',
*contextCfgPath)))
log.info('configuring context ID %s (at %s), composite key: %s' %
(contextId, '.'.join(contextCfgPath), k))
contextIdList.append((contextId, re.compile(k)))
duplicates = {}
for contentCfgPath in cfgTree.getPathsToAttr('snmp-content-id'):
contentId = cfgTree.getAttrValue('snmp-content-id', *contentCfgPath)
if contentId in duplicates:
log.error('duplicate snmp-content-id=%s at %s and %s' %
(contentId, '.'.join(contentCfgPath), '.'.join(
duplicates[contentId])))
return
duplicates[contentId] = contentCfgPath
for x in cfgTree.getAttrValue('snmp-pdu-oid-prefix-pattern-list',
*contentCfgPath, **dict(vector=True)):
k = '#'.join([
cfgTree.getAttrValue('snmp-pdu-type-pattern', *contentCfgPath),
x
])
log.info('configuring content ID %s (at %s), composite key: %s' %
(contentId, '.'.join(contentCfgPath), k))
contentIdList.append((contentId, re.compile(k)))
del duplicates
for pluginCfgPath in cfgTree.getPathsToAttr('using-plugin-id-list'):
pluginIdList = cfgTree.getAttrValue('using-plugin-id-list',
*pluginCfgPath,
**dict(vector=True))
log.info('configuring plugin ID(s) %s (at %s)...' %
(','.join(pluginIdList), '.'.join(pluginCfgPath)))
for credId in cfgTree.getAttrValue('matching-snmp-credentials-id-list',
*pluginCfgPath,
**dict(vector=True)):
for peerId in cfgTree.getAttrValue('matching-snmp-peer-id-list',
*pluginCfgPath,
**dict(vector=True)):
for contextId in cfgTree.getAttrValue(
'matching-snmp-context-id-list', *pluginCfgPath,
**dict(vector=True)):
for contentId in cfgTree.getAttrValue(
'matching-snmp-content-id-list', *pluginCfgPath,
**dict(vector=True)):
k = credId, contextId, peerId, contentId
if k in pluginIdMap:
log.error(
'duplicate snmp-credentials-id %s, snmp-context-id %s, snmp-peer-id %s, snmp-content-id %s at plugin-id(s) %s'
% (credId, contextId, peerId, contentId,
','.join(pluginIdList)))
return
else:
log.info(
'configuring plugin(s) %s (at %s), composite key: %s'
% (','.join(pluginIdList),
'.'.join(pluginCfgPath), '/'.join(k)))
for pluginId in pluginIdList:
if not pluginManager.hasPlugin(pluginId):
log.error(
'undefined plugin ID %s referenced at %s'
% (pluginId, '.'.join(pluginCfgPath)))
return
pluginIdMap[k] = pluginIdList
for routeCfgPath in cfgTree.getPathsToAttr('using-trunk-id-list'):
trunkIdList = cfgTree.getAttrValue('using-trunk-id-list',
*routeCfgPath, **dict(vector=True))
log.info('configuring destination trunk ID(s) %s (at %s)...' %
(','.join(trunkIdList), '.'.join(routeCfgPath)))
for credId in cfgTree.getAttrValue('matching-snmp-credentials-id-list',
*routeCfgPath, **dict(vector=True)):
for peerId in cfgTree.getAttrValue('matching-snmp-peer-id-list',
*routeCfgPath,
**dict(vector=True)):
for contextId in cfgTree.getAttrValue(
'matching-snmp-context-id-list', *routeCfgPath,
**dict(vector=True)):
for contentId in cfgTree.getAttrValue(
'matching-snmp-content-id-list', *routeCfgPath,
**dict(vector=True)):
k = credId, contextId, peerId, contentId
if k in trunkIdMap:
log.error(
'duplicate snmp-credentials-id %s, snmp-context-id %s, snmp-peer-id %s, snmp-content-id %s at trunk-id(s) %s'
% (credId, contextId, peerId, contentId,
','.join(trunkIdList)))
return
else:
trunkIdMap[k] = trunkIdList
log.info(
'configuring trunk routing to %s (at %s), composite key: %s'
% (','.join(trunkIdList), '.'.join(routeCfgPath),
'/'.join(k)))
def dataCbFun(trunkId, msgId, msg):
log.debug('message ID %s received from trunk %s' % (msgId, trunkId))
trunkingManager = TrunkingManager(dataCbFun)
def getTrunkAddr(a, port=0):
f = lambda h, p=port: (h, int(p))
try:
return f(*a.split(':'))
except Exception:
raise SnmpfwdError('improper IPv4 endpoint %s' % a)
for trunkCfgPath in cfgTree.getPathsToAttr('trunk-id'):
trunkId = cfgTree.getAttrValue('trunk-id', *trunkCfgPath)
secret = cfgTree.getAttrValue('trunk-crypto-key', *trunkCfgPath,
**dict(default=''))
secret = secret and (secret * ((16 // len(secret)) + 1))[:16]
log.info('configuring trunk ID %s (at %s)...' %
(trunkId, '.'.join(trunkCfgPath)))
connectionMode = cfgTree.getAttrValue('trunk-connection-mode',
*trunkCfgPath)
if connectionMode == 'client':
trunkingManager.addClient(
trunkId,
getTrunkAddr(
cfgTree.getAttrValue('trunk-bind-address', *trunkCfgPath)),
getTrunkAddr(
cfgTree.getAttrValue('trunk-peer-address', *trunkCfgPath),
30201),
cfgTree.getAttrValue('trunk-ping-period',
*trunkCfgPath,
default=0,
expect=int), secret)
log.info(
'new trunking client from %s to %s' %
(cfgTree.getAttrValue('trunk-bind-address', *trunkCfgPath),
cfgTree.getAttrValue('trunk-peer-address', *trunkCfgPath)))
if connectionMode == 'server':
trunkingManager.addServer(
getTrunkAddr(
cfgTree.getAttrValue('trunk-bind-address', *trunkCfgPath),
30201),
cfgTree.getAttrValue('trunk-ping-period',
*trunkCfgPath,
default=0,
expect=int), secret)
log.info(
'new trunking server at %s' %
(cfgTree.getAttrValue('trunk-bind-address', *trunkCfgPath)))
transportDispatcher.registerTimerCbFun(trunkingManager.setupTrunks,
random.randrange(1, 5))
transportDispatcher.registerTimerCbFun(trunkingManager.monitorTrunks,
random.randrange(1, 5))
try:
daemon.dropPrivileges(procUser, procGroup)
except Exception:
log.error('can not drop privileges: %s' % sys.exc_info()[1])
return
if not foregroundFlag:
try:
daemon.daemonize(pidFile)
except Exception:
log.error('can not daemonize process: %s' % sys.exc_info()[1])
return
# Run mainloop
log.info('starting I/O engine...')
transportDispatcher.jobStarted(1) # server job would never finish
# Python 2.4 does not support the "finally" clause
while True:
try:
transportDispatcher.runDispatcher()
except (PySnmpError, SnmpfwdError, socket.error):
log.error(str(sys.exc_info()[1]))
continue
except Exception:
transportDispatcher.closeDispatcher()
raise
self.releaseStateInformation(stateReference)
credIdMap = {}
peerIdMap = {}
contextIdList = []
contentIdList = []
contentIdMap = {}
pluginIdMap = {}
trunkIdMap = {}
engineIdMap = {}
transportDispatcher = AsynsockDispatcher()
transportDispatcher.registerRoutingCbFun(lambda td, t, d: td)
transportDispatcher.setSocketMap() # use global asyncore socket map
snmpPduTypesMap = {
rfc1905.GetRequestPDU.tagSet: 'GET',
rfc1905.SetRequestPDU.tagSet: 'SET',
rfc1905.GetNextRequestPDU.tagSet: 'GETNEXT',
rfc1905.GetBulkRequestPDU.tagSet: 'GETBULK',
rfc1905.ResponsePDU.tagSet: 'RESPONSE'
}
def requestObserver(snmpEngine, execpoint, variables, cbCtx):
cbCtx['snmp-credentials-id'] = macro.expandMacros(
credIdMap.get(
(str(snmpEngine.snmpEngineID), variables['transportDomain'],
variables['securityModel'], variables['securityLevel'],
class SNMPEngine(object):
"""
Main object for SNMP querying, both get and set. There are several
different methods for this object:
get_one(): Requires a single OID and returns a single value or
{ oid: value } with oid
get_list(): Requires a list of OIDs and returns a list of values,
one per OID or a dictionary of oid/values
get_table(): Requires a list of OIDs and returns a list of a list
columns are each oid, the row is each entry for that column
[[oid1val1, oid2val1, oid3val1],[oid1val2, oid2val2, oid3val3]]
Used for returning all from same SNMP table
get_many(): Requires a list of OIDs and returns a list of lists,
row is each oid, which is a list of returned values
Used for different tables
The with_oid option is None by default, meaning no OID is returned
with the values. When this option is set, instead of just the values
a (oid, value) tuple is returned. The option is a number of digits
to return, with 0 meaning the entire OID
"""
zmq_core = None
logger = None
active_requests = {}
default_timeout = 3 # number of seconds before item is considered gone
max_attempts = 3
def __init__(self, zmq_core, logger):
self.zmq_core = zmq_core
self.logger = logger
self.scheduler = SNMPScheduler(logger=logger)
self.transport_dispatcher = AsynsockDispatcher()
self.transport_dispatcher.setSocketMap(zmq_core.socket_map)
snmp_engine = engine.SnmpEngine()
snmp_engine.registerTransportDispatcher(self.transport_dispatcher)
self.cmd_gen = cmdgen.AsynCommandGenerator(snmpEngine=snmp_engine)
def get_int(self, snmphost, oid, cb_func, **kw):
""" Return a single integer value """
return self.get_one(snmphost, oid, cb_func, filter='int', **kw)
def get_str(self, snmphost, oid, cb_func, **kw):
""" Return a single string value """
return self.get_one(snmphost, oid, cb_func, filter='str', **kw)
def get_one(self, snmphost, oid, cb_func, with_oid=None, **kw):
""" Return a single value from a single OID """
req = SNMPGetRequest(snmphost, snmphost.ro_community)
req.with_oid = with_oid
req.add_oid(oid, callback=cb_func, **kw)
return self.get(req)
def get_list(self, snmphost, oids, cb_func, with_oid=None, **kw):
""" Return a list of one value per given OID """
req = SNMPGetListRequest(snmphost, snmphost.ro_community, cb_func,
**kw)
req.with_oid = with_oid
for oid in oids:
req.add_oid(oid)
return self.get(req)
def get_many(self, snmphost, oids, cb_func, with_oid=None, **kw):
""" Return a list of a list. Each primary list maps to
one of the requested oid, which will return a list of
values for that oid
"""
req = SNMPRequest(snmphost,
snmphost.ro_community,
callback=cb_func,
**kw)
req.with_oid = with_oid
req.set_many()
req.set_replyall(True)
for oid in oids:
req.add_oid(oid)
return self.get(req)
def get_table(self, snmphost, oids, cb_func, with_oid=None, **kw):
if type(oids) in (str, unicode):
oids = (oids, )
req = SNMPGetTableRequest(snmphost, snmphost.ro_community, cb_func,
**kw)
req.with_oid = with_oid
for oid in oids:
req.add_oid(oid)
return self.get(req)
def get(self, request):
if request.community.community == '':
request.callback_none()
return True
self.scheduler.request_add(request)
return True
def set(self, request):
if request.community.community == '':
request.callback_none()
return True
self.scheduler.request_add(request)
def poll(self):
"""
This method should be periodically called to gather all pending
requests and handle any responses from remote agents.
Returns number of requests udner control if there is still things to do
"""
reqcount = 0
# check timeouts
try:
if self.transport_dispatcher.jobsArePending():
self.transport_dispatcher.handleTimerTick(time.time())
except AttributeError:
pass
except PySnmpError as errmsg:
self.logger.error('Problem with SNMP: %s', errmsg)
self._check_waiting_requests()
reqcount += len(self.scheduler.waiting_requests)
reqcount += len(self.active_requests)
return reqcount
def _request_finished(self, request_id):
""" Request with given request ID is finished """
self._del_request(request_id)
self.scheduler.request_received(request_id)
def _del_request(self, reqid):
try:
del (self.active_requests[reqid])
except KeyError:
pass
def _check_waiting_requests(self):
"""
Run a loop asking the scheduler to find all requests we can kick
off on this cycle. Returns when there is no more to send. """
while True:
request = self.scheduler.request_pop()
if request is None:
return
self.send_request(request)
def send_request(self, request, first=True):
request.prepare(self.cmd_gen, self._snmp_callback)
if first:
self.scheduler.request_sent(request.id)
self.active_requests[request.id] = request
request.attempt = 1
else:
request.attempt += 1
request.timeout = time.time() + self.default_timeout
@classmethod
def _format_value(cls, request, oid, raw_value):
""" Parse the SNMP returned value """
if isinstance(raw_value, (NoSuchInstance, NoSuchObject)):
val = None
else:
val = raw_value.prettyPrint()
if request.with_oid is None:
return val
else:
return (oid[-request.with_oid:].prettyPrint(), val)
def _parse_many(self, request, var_binds):
""" Get the raw var_binds into a list of oids which
have a list/dict of values """
if request.varbinds is None:
request.varbinds = [[] for x in request.oids]
need_more = False
for row in var_binds:
for idx, (oid, val) in enumerate(row):
if request.oids[idx].is_prefix_of(oid):
request.varbinds[idx].append(
self._format_value(request, oid, val))
# See if we need more data
need_more = False
for idx, (oid, val) in enumerate(var_binds[-1]):
if request.oids[idx].is_prefix_of(oid):
need_more = True
break
return need_more
def _parse_table(self, request, var_binds):
""" Parse the varbinds into a table which is a list of rows.
Each row is a list or dict of values for the same entity """
if request.varbinds is None:
request.varbinds = []
for row in var_binds:
row_data = []
for idx, (oid, val) in enumerate(row):
if request.oids[idx].is_prefix_of(oid):
row_data.append(self._format_value(request, oid, val))
else:
return False
request.varbinds.append(row_data)
return True
def _parse_row(self, request, var_binds):
first_req_oid = None
row_vals = []
for idx, (oid, val) in enumerate(var_binds):
try:
req_oid = request.oids[idx]
except IndexError:
self.logger.error('No request oid for %s', oid.prettyPrint())
continue
if first_req_oid is None:
first_req_oid = req_oid
if request.is_replyall():
row_vals.append(self._format_value(request, oid, val))
else:
request.callback_single(req_oid,
self._format_value(request, oid, val))
if request.is_replyall():
request.varbinds = row_vals
request.callback_table()
def _snmp_callback(self, request_id, error_indication, error_status,
error_index, var_binds, request):
if error_indication:
self.logger.debug('H: %d Error with SNMP: %s', request.host.id,
error_indication)
self._request_finished(request.id)
request.callback_none(error_indication)
return False
if error_status:
self.logger.debug(
'H:%d SNMP Errstat %s at %s', request.host.id,
error_status.prettyPrint(),
error_index and var_binds[int(error_index) - 1] or '?')
self._request_finished(request.id)
request.callback_none(error_status)
return False
if request.is_many():
if self._parse_many(request, var_binds):
return True
elif request.is_table():
if self._parse_table(request, var_binds):
return True
else:
self._parse_row(request, var_binds)
if request.is_table() or request.is_many():
request.callback_table()
self._request_finished(request.id)
return False
def main():
class LogString(LazyLogString):
GROUPINGS = [
['callflow-id'],
['trunk-id'],
[
'server-snmp-engine-id', 'server-snmp-transport-domain',
'server-snmp-peer-address', 'server-snmp-peer-port',
'server-snmp-bind-address', 'server-snmp-bind-port',
'server-snmp-security-model', 'server-snmp-security-level',
'server-snmp-security-name', 'server-snmp-context-engine-id',
'server-snmp-context-name', 'server-snmp-pdu',
'server-snmp-entity-id'
],
[
'server-snmp-credentials-id', 'server-snmp-context-id',
'server-snmp-content-id', 'server-snmp-peer-id',
'server-classification-id'
],
[
'snmp-peer-id', 'snmp-bind-address', 'snmp-bind-port',
'snmp-peer-address', 'snmp-peer-port',
'snmp-context-engine-id', 'snmp-context-name', 'snmp-pdu'
],
]
FORMATTERS = {
'server-snmp-pdu': LazyLogString.prettyVarBinds,
'snmp-pdu': LazyLogString.prettyVarBinds,
}
def snmpCbFun(snmpEngine, sendRequestHandle, errorIndication, rspPDU,
cbCtx):
trunkId, msgId, trunkReq, pluginIdList, reqCtx = cbCtx
trunkRsp = {
'callflow-id': trunkReq['callflow-id'],
'snmp-pdu': rspPDU,
}
logCtx = LogString(trunkRsp)
if errorIndication:
log.info('received SNMP error-indication "%s"' % errorIndication,
ctx=logCtx)
trunkRsp['error-indication'] = errorIndication
if rspPDU:
reqPdu = trunkReq['server-snmp-pdu']
for pluginId in pluginIdList:
if reqPdu.tagSet in rfc3411.notificationClassPDUs:
st, rspPDU = pluginManager.processNotificationResponse(
pluginId, snmpEngine, rspPDU, trunkReq, reqCtx)
elif reqPdu.tagSet not in rfc3411.unconfirmedClassPDUs:
st, rspPDU = pluginManager.processCommandResponse(
pluginId, snmpEngine, rspPDU, trunkReq, reqCtx)
else:
log.error('ignoring unsupported PDU', ctx=logCtx)
break
if st == status.BREAK:
log.debug('plugin %s inhibits other plugins' % pluginId,
ctx=logCtx)
break
elif st == status.DROP:
log.debug(
'received SNMP %s, plugin %s muted response' %
(errorIndication and 'error' or 'response', pluginId),
ctx=logCtx)
trunkRsp['snmp-pdu'] = None
break
try:
trunkingManager.sendRsp(trunkId, msgId, trunkRsp)
except SnmpfwdError:
log.error('received SNMP %s message, trunk message not sent "%s"' %
(msgId, sys.exc_info()[1]),
ctx=logCtx)
return
log.debug('received SNMP %s message, forwarded as trunk message #%s' %
(errorIndication and 'error' or 'response', msgId),
ctx=logCtx)
#
# The following needs proper support in pysnmp. Meanwhile - monkey patching!
#
def makeTargetAddrOverride(targetAddr):
endpoints = []
def getTargetAddr(snmpEngine, snmpTargetAddrName):
addrInfo = list(targetAddr(snmpEngine, snmpTargetAddrName))
if endpoints:
peerAddr, bindAddr = endpoints.pop(), endpoints.pop()
try:
addrInfo[1] = addrInfo[1].__class__(
peerAddr).setLocalAddress(bindAddr)
except Exception:
raise PySnmpError(
'failure replacing bind address %s -> %s for transport '
'domain %s' % (addrInfo[1], bindAddr, addrInfo[0]))
return addrInfo
def updateEndpoints(bindAddr, peerAddr):
endpoints.extend((bindAddr, peerAddr))
return getTargetAddr, updateEndpoints
lcd.getTargetAddr, updateEndpoints = makeTargetAddrOverride(
lcd.getTargetAddr)
def trunkCbFun(trunkId, msgId, trunkReq):
for key in tuple(trunkReq):
if key != 'callflow-id':
trunkReq['server-' + key] = trunkReq[key]
del trunkReq[key]
trunkReq['trunk-id'] = trunkId
k = [
str(x) for x in (trunkReq['server-snmp-engine-id'],
trunkReq['server-snmp-transport-domain'],
trunkReq['server-snmp-peer-address'] + ':' +
str(trunkReq['server-snmp-peer-port']),
trunkReq['server-snmp-bind-address'] + ':' +
str(trunkReq['server-snmp-bind-port']),
trunkReq['server-snmp-security-model'],
trunkReq['server-snmp-security-level'],
trunkReq['server-snmp-security-name'],
trunkReq['server-snmp-context-engine-id'],
trunkReq['server-snmp-context-name'])
]
k.append(snmpPduTypesMap.get(trunkReq['server-snmp-pdu'].tagSet, '?'))
k.append('|'.join([
str(x[0])
for x in v2c.apiPDU.getVarBinds(trunkReq['server-snmp-pdu'])
]))
k = '#'.join(k)
for x, y in origCredIdList:
if y.match(k):
origPeerId = trunkReq[
'server-snmp-entity-id'] = macro.expandMacro(x, trunkReq)
break
else:
origPeerId = None
k = [
str(x) for x in (trunkReq['server-snmp-credentials-id'],
trunkReq['server-snmp-context-id'],
trunkReq['server-snmp-content-id'],
trunkReq['server-snmp-peer-id'])
]
k = '#'.join(k)
for x, y in srvClassIdList:
if y.match(k):
srvClassId = trunkReq[
'server-classification-id'] = macro.expandMacro(
x, trunkReq)
break
else:
srvClassId = None
logCtx = LogString(trunkReq)
errorIndication = None
peerIdList = routingMap.get(
(origPeerId, srvClassId, macro.expandMacro(trunkId, trunkReq)))
if not peerIdList:
log.error('unroutable trunk message #%s' % msgId, ctx=logCtx)
errorIndication = 'no route to SNMP peer configured'
cbCtx = trunkId, msgId, trunkReq, (), {}
if errorIndication:
snmpCbFun(None, None, errorIndication, None, cbCtx)
return
pluginIdList = pluginIdMap.get(
(origPeerId, srvClassId, macro.expandMacro(trunkId, trunkReq)))
for peerId in peerIdList:
peerId = macro.expandMacro(peerId, trunkReq)
trunkReqCopy = trunkReq.copy()
(snmpEngine, contextEngineId, contextName, bindAddr, bindAddrMacro,
peerAddr, peerAddrMacro) = peerIdMap[peerId]
if bindAddrMacro:
bindAddr = macro.expandMacro(bindAddrMacro, trunkReqCopy), 0
if peerAddrMacro:
peerAddr = macro.expandMacro(peerAddrMacro, trunkReqCopy), 161
if bindAddr and peerAddr:
updateEndpoints(bindAddr, peerAddr)
trunkReqCopy['snmp-peer-id'] = peerId
trunkReqCopy['snmp-context-engine-id'] = contextEngineId
trunkReqCopy['snmp-context-name'] = contextName
trunkReqCopy['snmp-bind-address'], trunkReqCopy[
'snmp-bind-port'] = bindAddr
trunkReqCopy['snmp-peer-address'], trunkReqCopy[
'snmp-peer-port'] = peerAddr
logCtx.update(trunkReqCopy)
pdu = trunkReqCopy['server-snmp-pdu']
if pluginIdList:
reqCtx = {}
cbCtx = trunkId, msgId, trunkReqCopy, pluginIdList, reqCtx
for pluginNum, pluginId in enumerate(pluginIdList):
if pdu.tagSet in rfc3411.notificationClassPDUs:
st, pdu = pluginManager.processNotificationRequest(
pluginId, snmpEngine, pdu, trunkReqCopy, reqCtx)
elif pdu.tagSet not in rfc3411.unconfirmedClassPDUs:
st, pdu = pluginManager.processCommandRequest(
pluginId, snmpEngine, pdu, trunkReqCopy, reqCtx)
else:
log.error('ignoring unsupported PDU', ctx=logCtx)
break
if st == status.BREAK:
log.debug('plugin %s inhibits other plugins' %
pluginId,
ctx=logCtx)
cbCtx = trunkId, msgId, trunkReqCopy, pluginIdList[:
pluginNum], reqCtx
break
elif st == status.DROP:
log.debug(
'received trunk message #%s, plugin %s muted request'
% (msgId, pluginId),
ctx=logCtx)
snmpCbFun(snmpEngine, None, None, None, cbCtx)
return
elif st == status.RESPOND:
log.debug(
'received trunk message #%s, plugin %s forced immediate response'
% (msgId, pluginId),
ctx=logCtx)
snmpCbFun(snmpEngine, None, None, pdu, cbCtx)
return
snmpMessageSent = False
if pdu.tagSet in rfc3411.notificationClassPDUs:
if pdu.tagSet in rfc3411.unconfirmedClassPDUs:
try:
notificationOriginator.sendPdu(
snmpEngine, peerId,
macro.expandMacro(contextEngineId, trunkReq),
macro.expandMacro(contextName, trunkReq), pdu)
snmpMessageSent = True
except PySnmpError:
errorIndication = 'failure sending SNMP notification'
log.error('trunk message #%s, SNMP error: %s' %
(msgId, sys.exc_info()[1]),
ctx=logCtx)
else:
errorIndication = None
# respond to trunk right away
snmpCbFun(snmpEngine, None, errorIndication, None, cbCtx)
else:
try:
notificationOriginator.sendPdu(
snmpEngine, peerId,
macro.expandMacro(contextEngineId, trunkReq),
macro.expandMacro(contextName, trunkReq), pdu,
snmpCbFun, cbCtx)
snmpMessageSent = True
except PySnmpError:
log.error('trunk message #%s, SNMP error: %s' %
(msgId, sys.exc_info()[1]),
ctx=logCtx)
elif pdu.tagSet not in rfc3411.unconfirmedClassPDUs:
try:
commandGenerator.sendPdu(
snmpEngine, peerId,
macro.expandMacro(contextEngineId, trunkReq),
macro.expandMacro(contextName, trunkReq), pdu,
snmpCbFun, cbCtx)
snmpMessageSent = True
except PySnmpError:
errorIndication = 'failure sending SNMP command'
log.error('trunk message #%s, SNMP error: %s' %
(msgId, sys.exc_info()[1]),
ctx=logCtx)
# respond to trunk right away
snmpCbFun(snmpEngine, None, errorIndication, None, cbCtx)
else:
log.error('ignoring unsupported PDU', ctx=logCtx)
if snmpMessageSent:
log.debug(
'received trunk message #%s, forwarded as SNMP message' %
msgId,
ctx=logCtx)
#
# Main script body starts here
#
helpMessage = """\
Usage: %s [--help]
[--version ]
[--debug-snmp=<%s>]
[--debug-asn1=<%s>]
[--daemonize]
[--process-user=<uname>] [--process-group=<gname>]
[--pid-file=<file>]
[--logging-method=<%s[:args>]>]
[--log-level=<%s>]
[--config-file=<file>]""" % (sys.argv[0], '|'.join([
x for x in getattr(pysnmp_debug, 'FLAG_MAP',
getattr(pysnmp_debug, 'flagMap', ()))
if x != 'mibview'
]), '|'.join([
x for x in getattr(pyasn1_debug, 'FLAG_MAP',
getattr(pyasn1_debug, 'flagMap', ()))
]), '|'.join(log.methodsMap), '|'.join(log.levelsMap))
try:
opts, params = getopt.getopt(sys.argv[1:], 'hv', [
'help', 'version', 'debug=', 'debug-snmp=', 'debug-asn1=',
'daemonize', 'process-user='******'process-group=', 'pid-file=',
'logging-method=', 'log-level=', 'config-file='
])
except Exception:
sys.stderr.write('ERROR: %s\r\n%s\r\n' %
(sys.exc_info()[1], helpMessage))
return
if params:
sys.stderr.write('ERROR: extra arguments supplied %s\r\n%s\r\n' %
(params, helpMessage))
return
pidFile = ''
cfgFile = CONFIG_FILE
foregroundFlag = True
procUser = procGroup = None
loggingMethod = ['stderr']
loggingLevel = None
for opt in opts:
if opt[0] == '-h' or opt[0] == '--help':
sys.stderr.write("""\
Synopsis:
SNMP Proxy Forwarder: client part. Receives SNMP PDUs via one or many
encrypted trunks established with the Forwarder's Agent part(s) running
elsewhere and routes PDUs to built-in SNMP Managers for further
transmission towards SNMP Agents.
Can implement complex routing and protocol conversion logic through
analyzing parts of SNMP messages and matching them against proxying rules.
Documentation:
http://snmplabs.com/snmpfwd/
%s
""" % helpMessage)
return
if opt[0] == '-v' or opt[0] == '--version':
import snmpfwd
import pysnmp
import pyasn1
sys.stderr.write("""\
SNMP Proxy Forwarder version %s, written by Ilya Etingof <*****@*****.**>
Using foundation libraries: pysnmp %s, pyasn1 %s.
Python interpreter: %s
Software documentation and support at http://snmplabs.com/snmpfwd/
%s
""" % (snmpfwd.__version__, hasattr(pysnmp, '__version__')
and pysnmp.__version__ or 'unknown', hasattr(pyasn1, '__version__')
and pyasn1.__version__ or 'unknown', sys.version, helpMessage))
return
elif opt[0] == '--debug-snmp':
pysnmp_debug.setLogger(
pysnmp_debug.Debug(*opt[1].split(','),
**dict(loggerName=PROGRAM_NAME +
'.pysnmp')))
elif opt[0] == '--debug-asn1':
pyasn1_debug.setLogger(
pyasn1_debug.Debug(*opt[1].split(','),
**dict(loggerName=PROGRAM_NAME +
'.pyasn1')))
elif opt[0] == '--daemonize':
foregroundFlag = False
elif opt[0] == '--process-user':
procUser = opt[1]
elif opt[0] == '--process-group':
procGroup = opt[1]
elif opt[0] == '--pid-file':
pidFile = opt[1]
elif opt[0] == '--logging-method':
loggingMethod = opt[1].split(':')
elif opt[0] == '--log-level':
loggingLevel = opt[1]
elif opt[0] == '--config-file':
cfgFile = opt[1]
with daemon.PrivilegesOf(procUser, procGroup):
try:
log.setLogger(PROGRAM_NAME, *loggingMethod, **dict(force=True))
if loggingLevel:
log.setLevel(loggingLevel)
except SnmpfwdError:
sys.stderr.write('%s\r\n%s\r\n' % (sys.exc_info()[1], helpMessage))
return
try:
cfgTree = cparser.Config().load(cfgFile)
except SnmpfwdError:
log.error('configuration parsing error: %s' % sys.exc_info()[1])
return
if cfgTree.getAttrValue('program-name', '', default=None) != PROGRAM_NAME:
log.error('config file %s does not match program name %s' %
(cfgFile, PROGRAM_NAME))
return
if cfgTree.getAttrValue('config-version', '',
default=None) != CONFIG_VERSION:
log.error(
'config file %s version is not compatible with program version %s'
% (cfgFile, CONFIG_VERSION))
return
random.seed()
#
# SNMPv3 CommandGenerator & NotificationOriginator implementation
#
origCredIdList = []
srvClassIdList = []
peerIdMap = {}
pluginIdMap = {}
routingMap = {}
engineIdMap = {}
commandGenerator = cmdgen.CommandGenerator()
notificationOriginator = ntforg.NotificationOriginator()
transportDispatcher = AsynsockDispatcher()
transportDispatcher.registerRoutingCbFun(lambda td, t, d: td)
transportDispatcher.setSocketMap() # use global asyncore socket map
pluginManager = PluginManager(macro.expandMacros(
cfgTree.getAttrValue('plugin-modules-path-list',
'',
default=[],
vector=True),
{'config-dir': os.path.dirname(cfgFile)}),
progId=PROGRAM_NAME,
apiVer=PLUGIN_API_VERSION)
for pluginCfgPath in cfgTree.getPathsToAttr('plugin-id'):
pluginId = cfgTree.getAttrValue('plugin-id', *pluginCfgPath)
pluginMod = cfgTree.getAttrValue('plugin-module', *pluginCfgPath)
pluginOptions = macro.expandMacros(
cfgTree.getAttrValue('plugin-options', *pluginCfgPath,
**dict(default=[], vector=True)),
{'config-dir': os.path.dirname(cfgFile)})
log.info(
'configuring plugin ID %s (at %s) from module %s with options %s...'
% (pluginId, '.'.join(pluginCfgPath), pluginMod,
', '.join(pluginOptions) or '<none>'))
with daemon.PrivilegesOf(procUser, procGroup):
try:
pluginManager.loadPlugin(pluginId, pluginMod, pluginOptions)
except SnmpfwdError:
log.error('plugin %s not loaded: %s' %
(pluginId, sys.exc_info()[1]))
return
for peerEntryPath in cfgTree.getPathsToAttr('snmp-peer-id'):
peerId = cfgTree.getAttrValue('snmp-peer-id', *peerEntryPath)
if peerId in peerIdMap:
log.error('duplicate snmp-peer-id=%s at %s' %
(peerId, '.'.join(peerEntryPath)))
return
log.info('configuring SNMP peer %s (at %s)...' %
(peerId, '.'.join(peerEntryPath)))
engineId = cfgTree.getAttrValue('snmp-engine-id', *peerEntryPath)
if engineId in engineIdMap:
snmpEngine, snmpContext, snmpEngineMap = engineIdMap[engineId]
log.info('using engine-id: %s' %
snmpEngine.snmpEngineID.prettyPrint())
else:
snmpEngine = engine.SnmpEngine(snmpEngineID=engineId)
snmpContext = context.SnmpContext(snmpEngine)
snmpEngineMap = {
'transportDomain': {},
'securityName': {},
'credIds': set()
}
engineIdMap[engineId] = snmpEngine, snmpContext, snmpEngineMap
log.info('new engine-id %s' %
snmpEngine.snmpEngineID.prettyPrint())
transportDomain = cfgTree.getAttrValue('snmp-transport-domain',
*peerEntryPath)
transportDomain = rfc1902.ObjectName(str(transportDomain))
if (transportDomain[:len(udp.domainName)] != udp.domainName and udp6
and transportDomain[:len(udp6.domainName)] != udp6.domainName):
log.error('unknown transport domain %s' % (transportDomain, ))
return
transportOptions = cfgTree.getAttrValue(
'snmp-transport-options', *peerEntryPath,
**dict(default=[], vector=True))
bindAddr = cfgTree.getAttrValue('snmp-bind-address', *peerEntryPath)
try:
bindAddr, bindAddrMacro = endpoint.parseTransportAddress(
transportDomain, bindAddr, transportOptions)
except SnmpfwdError:
log.error('bad snmp-bind-address specification %s at %s' %
(bindAddr, '.'.join(peerEntryPath)))
return
if transportDomain in snmpEngineMap['transportDomain']:
log.info('using transport endpoint with transport ID %s' %
(transportDomain, ))
else:
if transportDomain[:len(udp.domainName)] == udp.domainName:
transport = udp.UdpTransport()
else:
transport = udp6.Udp6Transport()
snmpEngine.registerTransportDispatcher(transportDispatcher,
transportDomain)
t = transport.openClientMode(bindAddr)
if 'transparent-proxy' in transportOptions:
t.enablePktInfo()
t.enableTransparent()
elif 'virtual-interface' in transportOptions:
t.enablePktInfo()
config.addSocketTransport(snmpEngine, transportDomain, t)
snmpEngineMap['transportDomain'][transportDomain] = bindAddr[
0], bindAddr[1], transportDomain
log.info(
'new transport endpoint at bind address [%s]:%s, options %s, transport ID %s'
%
(bindAddr[0], bindAddr[1], transportOptions
and '/'.join(transportOptions) or '<none>', transportDomain))
securityModel = cfgTree.getAttrValue('snmp-security-model',
*peerEntryPath)
securityModel = rfc1902.Integer(securityModel)
securityLevel = cfgTree.getAttrValue('snmp-security-level',
*peerEntryPath)
securityLevel = rfc1902.Integer(securityLevel)
securityName = cfgTree.getAttrValue('snmp-security-name',
*peerEntryPath)
contextEngineId = cfgTree.getAttrValue('snmp-context-engine-id',
*peerEntryPath,
**dict(default=None))
contextName = cfgTree.getAttrValue('snmp-context-name', *peerEntryPath,
**dict(default=''))
if securityModel in (1, 2):
if securityName in snmpEngineMap['securityName']:
if snmpEngineMap['securityName'][
securityName] == securityModel:
log.info('using security-name %s' % securityName)
else:
log.error(
'security-name %s already in use at security-model %s'
% (securityName, securityModel))
return
else:
communityName = cfgTree.getAttrValue('snmp-community-name',
*peerEntryPath)
config.addV1System(snmpEngine,
securityName,
communityName,
securityName=securityName)
log.info(
'new community-name %s, security-model %s, security-name %s, security-level %s'
% (communityName, securityModel, securityName,
securityLevel))
snmpEngineMap['securityName'][securityName] = securityModel
elif securityModel == 3:
if securityName in snmpEngineMap['securityName']:
if snmpEngineMap['securityName'][
securityName] == securityModel:
log.info('using USM security-name: %s' % securityName)
else:
raise SnmpfwdError(
'security-name %s already in use at security-model %s'
% (securityName, securityModel))
else:
usmUser = cfgTree.getAttrValue('snmp-usm-user', *peerEntryPath)
securityEngineId = cfgTree.getAttrValue(
'snmp-security-engine-id', *peerEntryPath,
**dict(default=None))
if securityEngineId:
securityEngineId = rfc1902.OctetString(securityEngineId)
log.info(
'new USM user %s, security-model %s, security-level %s, '
'security-name %s, security-engine-id %s' %
(usmUser, securityModel, securityLevel, securityName,
securityEngineId and securityEngineId.prettyPrint()
or '<none>'))
if securityLevel in (2, 3):
usmAuthProto = cfgTree.getAttrValue(
'snmp-usm-auth-protocol', *peerEntryPath,
**dict(default=config.usmHMACMD5AuthProtocol))
try:
usmAuthProto = authProtocols[usmAuthProto.upper()]
except KeyError:
pass
usmAuthProto = rfc1902.ObjectName(usmAuthProto)
usmAuthKey = cfgTree.getAttrValue('snmp-usm-auth-key',
*peerEntryPath)
log.info(
'new USM authentication key: %s, authentication protocol: %s'
% (usmAuthKey, usmAuthProto))
if securityLevel == 3:
usmPrivProto = cfgTree.getAttrValue(
'snmp-usm-priv-protocol', *peerEntryPath,
**dict(default=config.usmDESPrivProtocol))
try:
usmPrivProto = privProtocols[usmPrivProto.upper()]
except KeyError:
pass
usmPrivProto = rfc1902.ObjectName(usmPrivProto)
usmPrivKey = cfgTree.getAttrValue(
'snmp-usm-priv-key', *peerEntryPath,
**dict(default=None))
log.info(
'new USM encryption key: %s, encryption protocol: %s'
% (usmPrivKey, usmPrivProto))
config.addV3User(
snmpEngine,
usmUser,
usmAuthProto,
usmAuthKey,
usmPrivProto,
usmPrivKey,
)
else:
config.addV3User(snmpEngine,
usmUser,
usmAuthProto,
usmAuthKey,
securityEngineId=securityEngineId)
else:
config.addV3User(snmpEngine,
usmUser,
securityEngineId=securityEngineId)
snmpEngineMap['securityName'][securityName] = securityModel
else:
log.error('unknown security-model: %s' % securityModel)
sys.exit(1)
credId = '/'.join(
[str(x) for x in (securityName, securityLevel, securityModel)])
if credId in snmpEngineMap['credIds']:
log.info('using credentials ID %s...' % credId)
else:
config.addTargetParams(
snmpEngine, credId, securityName, securityLevel,
securityModel == 3 and 3 or securityModel - 1)
log.info(
'new credentials %s, security-name %s, security-level %s, security-model %s'
% (credId, securityName, securityLevel, securityModel))
snmpEngineMap['credIds'].add(credId)
peerAddr = cfgTree.getAttrValue('snmp-peer-address', *peerEntryPath)
try:
peerAddr, peerAddrMacro = endpoint.parseTransportAddress(
transportDomain, peerAddr, transportOptions, defaultPort=161)
except SnmpfwdError:
log.error('bad snmp-peer-address specification %s at %s' %
(peerAddr, '.'.join(peerEntryPath)))
return
timeout = cfgTree.getAttrValue('snmp-peer-timeout', *peerEntryPath)
retries = cfgTree.getAttrValue('snmp-peer-retries', *peerEntryPath)
config.addTargetAddr(snmpEngine, peerId, transportDomain, peerAddr,
credId, timeout, retries)
peerIdMap[
peerId] = snmpEngine, contextEngineId, contextName, bindAddr, bindAddrMacro, peerAddr, peerAddrMacro
log.info(
'new peer ID %s, bind address %s, peer address %s, timeout %s*0.01 secs, retries %s, credentials ID %s'
% (peerId, bindAddrMacro or '<default>', peerAddrMacro
or '%s:%s' % peerAddr, timeout, retries, credId))
duplicates = {}
# TODO: rename orig-* into server-* and orig-snmp-peer-id into server-snmp-entity-id
for origCredCfgPath in cfgTree.getPathsToAttr('orig-snmp-peer-id'):
origCredId = cfgTree.getAttrValue('orig-snmp-peer-id',
*origCredCfgPath)
if origCredId in duplicates:
log.error('duplicate orig-snmp-peer-id=%s at %s and %s' %
(origCredId, '.'.join(origCredCfgPath), '.'.join(
duplicates[origCredId])))
return
duplicates[origCredId] = origCredCfgPath
k = '#'.join(
(cfgTree.getAttrValue('orig-snmp-engine-id-pattern',
*origCredCfgPath),
cfgTree.getAttrValue('orig-snmp-transport-domain-pattern',
*origCredCfgPath),
cfgTree.getAttrValue('orig-snmp-peer-address-pattern',
*origCredCfgPath),
cfgTree.getAttrValue('orig-snmp-bind-address-pattern',
*origCredCfgPath),
cfgTree.getAttrValue('orig-snmp-security-model-pattern',
*origCredCfgPath),
cfgTree.getAttrValue('orig-snmp-security-level-pattern',
*origCredCfgPath),
cfgTree.getAttrValue('orig-snmp-security-name-pattern',
*origCredCfgPath),
cfgTree.getAttrValue('orig-snmp-context-engine-id-pattern',
*origCredCfgPath),
cfgTree.getAttrValue('orig-snmp-context-name-pattern',
*origCredCfgPath),
cfgTree.getAttrValue('orig-snmp-pdu-type-pattern',
*origCredCfgPath),
cfgTree.getAttrValue('orig-snmp-oid-prefix-pattern',
*origCredCfgPath)))
log.info(
'configuring original SNMP peer ID %s (at %s), composite key: %s' %
(origCredId, '.'.join(origCredCfgPath), k))
origCredIdList.append((origCredId, re.compile(k)))
duplicates = {}
for srvClassCfgPath in cfgTree.getPathsToAttr('server-classification-id'):
srvClassId = cfgTree.getAttrValue('server-classification-id',
*srvClassCfgPath)
if srvClassId in duplicates:
log.error('duplicate server-classification-id=%s at %s and %s' %
(srvClassId, '.'.join(srvClassCfgPath), '.'.join(
duplicates[srvClassId])))
return
duplicates[srvClassId] = srvClassCfgPath
k = '#'.join(
(cfgTree.getAttrValue('server-snmp-credentials-id-pattern',
*srvClassCfgPath),
cfgTree.getAttrValue('server-snmp-context-id-pattern',
*srvClassCfgPath),
cfgTree.getAttrValue('server-snmp-content-id-pattern',
*srvClassCfgPath),
cfgTree.getAttrValue('server-snmp-peer-id-pattern',
*srvClassCfgPath)))
log.info(
'configuring server classification ID %s (at %s), composite key: %s'
% (srvClassId, '.'.join(srvClassCfgPath), k))
srvClassIdList.append((srvClassId, re.compile(k)))
del duplicates
for pluginCfgPath in cfgTree.getPathsToAttr('using-plugin-id-list'):
pluginIdList = cfgTree.getAttrValue('using-plugin-id-list',
*pluginCfgPath,
**dict(vector=True))
log.info('configuring plugin ID(s) %s (at %s)...' %
(','.join(pluginIdList), '.'.join(pluginCfgPath)))
for credId in cfgTree.getAttrValue('matching-orig-snmp-peer-id-list',
*pluginCfgPath,
**dict(vector=True)):
for srvClassId in cfgTree.getAttrValue(
'matching-server-classification-id-list', *pluginCfgPath,
**dict(vector=True)):
for trunkId in cfgTree.getAttrValue('matching-trunk-id-list',
*pluginCfgPath,
**dict(vector=True)):
k = credId, srvClassId, trunkId
if k in pluginIdMap:
log.error(
'duplicate snmp-credentials-id=%s and server-classification-id=%s and trunk-id=%s at plugin-id %s'
% (credId, srvClassId, trunkId,
','.join(pluginIdList)))
return
else:
log.info(
'configuring plugin(s) %s (at %s), composite key: %s'
% (','.join(pluginIdList), '.'.join(pluginCfgPath),
'/'.join(k)))
for pluginId in pluginIdList:
if not pluginManager.hasPlugin(pluginId):
log.error(
'undefined plugin ID %s referenced at %s' %
(pluginId, '.'.join(pluginCfgPath)))
return
pluginIdMap[k] = pluginIdList
for routeCfgPath in cfgTree.getPathsToAttr('using-snmp-peer-id-list'):
peerIdList = cfgTree.getAttrValue('using-snmp-peer-id-list',
*routeCfgPath, **dict(vector=True))
log.info('configuring routing entry with peer IDs %s (at %s)...' %
(','.join(peerIdList), '.'.join(routeCfgPath)))
for credId in cfgTree.getAttrValue('matching-orig-snmp-peer-id-list',
*routeCfgPath, **dict(vector=True)):
for srvClassId in cfgTree.getAttrValue(
'matching-server-classification-id-list', *routeCfgPath,
**dict(vector=True)):
for trunkId in cfgTree.getAttrValue('matching-trunk-id-list',
*routeCfgPath,
**dict(vector=True)):
k = credId, srvClassId, trunkId
if k in routingMap:
log.error(
'duplicate snmp-credentials-id=%s and server-classification-id=%s and trunk-id=%s at snmp-peer-id %s'
% (credId, srvClassId, trunkId,
','.join(peerIdList)))
return
else:
for peerId in peerIdList:
if peerId not in peerIdMap:
log.error('missing peer-id %s at %s' %
(peerId, '.'.join(routeCfgPath)))
return
routingMap[k] = peerIdList
trunkingManager = TrunkingManager(trunkCbFun)
for trunkCfgPath in cfgTree.getPathsToAttr('trunk-id'):
trunkId = cfgTree.getAttrValue('trunk-id', *trunkCfgPath)
secret = cfgTree.getAttrValue('trunk-crypto-key', *trunkCfgPath,
**dict(default=''))
secret = secret and (secret * ((16 // len(secret)) + 1))[:16]
log.info('configuring trunk ID %s (at %s)...' %
(trunkId, '.'.join(trunkCfgPath)))
connectionMode = cfgTree.getAttrValue('trunk-connection-mode',
*trunkCfgPath)
if connectionMode == 'client':
trunkingManager.addClient(
trunkId,
parseTrunkEndpoint(
cfgTree.getAttrValue('trunk-bind-address', *trunkCfgPath)),
parseTrunkEndpoint(
cfgTree.getAttrValue('trunk-peer-address', *trunkCfgPath),
30201),
cfgTree.getAttrValue('trunk-ping-period',
*trunkCfgPath,
default=0,
expect=int), secret)
log.info(
'new trunking client from %s to %s' %
(cfgTree.getAttrValue('trunk-bind-address', *trunkCfgPath),
cfgTree.getAttrValue('trunk-peer-address', *trunkCfgPath)))
if connectionMode == 'server':
trunkingManager.addServer(
parseTrunkEndpoint(
cfgTree.getAttrValue('trunk-bind-address', *trunkCfgPath),
30201),
cfgTree.getAttrValue('trunk-ping-period',
*trunkCfgPath,
default=0,
expect=int), secret)
log.info(
'new trunking server at %s' %
(cfgTree.getAttrValue('trunk-bind-address', *trunkCfgPath)))
transportDispatcher.registerTimerCbFun(trunkingManager.setupTrunks,
random.randrange(1, 5))
transportDispatcher.registerTimerCbFun(trunkingManager.monitorTrunks,
random.randrange(1, 5))
if not foregroundFlag:
try:
daemon.daemonize(pidFile)
except Exception:
log.error('can not daemonize process: %s' % sys.exc_info()[1])
return
# Run mainloop
log.info('starting I/O engine...')
transportDispatcher.jobStarted(1) # server job would never finish
# Python 2.4 does not support the "finally" clause
with daemon.PrivilegesOf(procUser, procGroup, final=True):
while True:
try:
transportDispatcher.runDispatcher()
except (PySnmpError, SnmpfwdError, socket.error):
log.error(str(sys.exc_info()[1]))
continue
except Exception:
transportDispatcher.closeDispatcher()
raise
