如何在MIB树中添加变量？

Question

这是我从 http://snmplabs.com/pysnmp/examples/v3arch/asyncore/agent/cmdrsp/agent-side-mib-implementations.html 获得的示例代码这里他们给出了 "Multiple MIB trees under distinct context names" 的示例程序。


from pysnmp.entity import engine, config
from pysnmp.entity.rfc3413 import cmdrsp, context
from pysnmp.carrier.asyncore.dgram import udp
from pysnmp.smi import instrum, builder
from pysnmp.proto.api import v2c

# Create SNMP engine
snmpEngine = engine.SnmpEngine()

# Transport setup

# UDP over IPv4
config.addTransport(
    snmpEngine,
    udp.domainName,
    udp.UdpTransport().openServerMode(('127.0.0.1', 161))
)

# SNMPv3/USM setup

# user: usr-md5-none, auth: MD5, priv NONE
config.addV3User(
    snmpEngine, 'usr-md5-none',
    config.usmHMACMD5AuthProtocol, 'authkey1'
)

# Allow full MIB access for each user at VACM
config.addVacmUser(snmpEngine, 3, 'usr-md5-none', 'authNoPriv', (1, 3, 6, 1, 2, 1), (1, 3, 6, 1, 2, 1))

# Create an SNMP context with default ContextEngineId (same as SNMP engine ID)
snmpContext = context.SnmpContext(snmpEngine)

# Create multiple independent trees of MIB managed objects (empty so far)
mibTreeA = instrum.MibInstrumController(builder.MibBuilder())
mibTreeB = instrum.MibInstrumController(builder.MibBuilder())

# Register MIB trees at distinct SNMP Context names
snmpContext.registerContextName(v2c.OctetString('context-a'), mibTreeA)
snmpContext.registerContextName(v2c.OctetString('context-b'), mibTreeB)

# Register SNMP Applications at the SNMP engine for particular SNMP context
cmdrsp.GetCommandResponder(snmpEngine, snmpContext)
cmdrsp.SetCommandResponder(snmpEngine, snmpContext)
cmdrsp.NextCommandResponder(snmpEngine, snmpContext)
cmdrsp.BulkCommandResponder(snmpEngine, snmpContext)

# Register an imaginary never-ending job to keep I/O dispatcher running forever
snmpEngine.transportDispatcher.jobStarted(1)

# Run I/O dispatcher which would receive queries and send responses
try:
    snmpEngine.transportDispatcher.runDispatcher()

except:
    snmpEngine.transportDispatcher.closeDispatcher()
    raise

我尝试了以下 snmp walk

snmpwalk -v3 -u usr-md5-none -l authNoPriv -A authkey1 -n context-a 127.0.0.1 .1.3.6

我得到

SNMPv2-SMI::dod = No more variables left in this MIB View (It is past the end of the MIB tree)

我知道这是因为 MIB 树是空的。但是如何将我的数据添加到其中呢？

Answer 1

要一般添加或覆盖功能 MIB 树的 OID，您可以将以下代码添加到您提供的代码示例中：

...
mibBuilder = snmpContext.getMibInstrum().getMibBuilder()

MibScalar, MibScalarInstance = mibBuilder.importSymbols(
    'SNMPv2-SMI', 'MibScalar', 'MibScalarInstance'
)

class MyStaticMibScalarInstance(MibScalarInstance):
    def getValue(self, name, idx):
        currentDT = datetime.datetime.now()
        return self.getSyntax().clone(
            'Hello World! It\'s currently: ' + str(currentDT)
        )

mibBuilder.exportSymbols(
    '__MY_MIB', MibScalar((1, 3, 6, 1, 2, 1, 1, 1), v2c.OctetString()),
    MyStaticMibScalarInstance((1, 3, 6, 1, 2, 1, 1, 1), (0,), v2c.OctetString())
)

# Register SNMP Applications at the SNMP engine for particular SNMP context
cmdrsp.GetCommandResponder(snmpEngine, snmpContext)
...

# snmpwalk -v3 -u usr-md5-none -l authNoPriv -A authkey1 127.0.0.1 .1.3.6
iso.3.6.1.2.1.1.1.0 = STRING: "Hello World! It's currently: 2019-11-18 16:02:43.796005"
iso.3.6.1.2.1.1.2.0 = OID: iso.3.6.1.4.1.20408
iso.3.6.1.2.1.1.3.0 = Timeticks: (494) 0:00:04.94
iso.3.6.1.2.1.1.4.0 = ""
iso.3.6.1.2.1.1.5.0 = ""
iso.3.6.1.2.1.1.6.0 = ""
iso.3.6.1.2.1.1.7.0 = INTEGER: 0
iso.3.6.1.2.1.1.8.0 = Timeticks: (0) 0:00:00.00
iso.3.6.1.2.1.11.1.0 = Counter32: 13
iso.3.6.1.2.1.11.2.0 = Counter32: 0
iso.3.6.1.2.1.11.3.0 = Counter32: 0
iso.3.6.1.2.1.11.4.0 = Counter32: 0
iso.3.6.1.2.1.11.5.0 = Counter32: 0
iso.3.6.1.2.1.11.6.0 = Counter32: 0
iso.3.6.1.2.1.11.8.0 = Counter32: 0
iso.3.6.1.2.1.11.9.0 = Counter32: 0

如果您真的需要第二个上下文和独立树，您可以创建一个通用控制器来检查并发回任何您想要的内容。

# Create an SNMP context with default ContextEngineId (same as SNMP engine ID)
snmpContext = context.SnmpContext(snmpEngine)

# Very basic Management Instrumentation Controller without
# any Managed Objects attached. It supports only GET's and
# modded to react to a target OID, otherwise
# always echos request var-binds in response.
class EchoMibInstrumController(instrum.AbstractMibInstrumController):
    def readVars(self, varBinds, acInfo=(None, None)):
        retItem = []
        for ov in varBinds:
            if str(ov[0]) == '1.3.6.1.2.1.1.1.0':
                currentDT = datetime.datetime.now()
                retItem.extend([(ov[0], v2c.OctetString('Hello World! It\'s currently: %s' % str(currentDT)))])
            else:
                retItem.extend([(ov[0], v2c.OctetString('You queried OID %s' % ov[0]))])
        return retItem


# Create multiple independent trees of MIB managed objects (empty so far)
mibTreeA = EchoMibInstrumController()
mibTreeB = instrum.MibInstrumController(builder.MibBuilder())

# Register MIB trees at distinct SNMP Context names
snmpContext.registerContextName(v2c.OctetString('context-a'), mibTreeA)
snmpContext.registerContextName(v2c.OctetString('context-b'), mibTreeB)

snmpget -v3 -u usr-md5-none -l authNoPriv -A authkey1 -n context-a 127.0.0.1 .1.3.6.1.2.1.1.1.0

# snmpget -v3 -u usr-md5-none -l authNoPriv -A authkey1 127.0.0.1 .1.3.6.1.2.1.1.1.0
iso.3.6.1.2.1.1.1.0 = STRING: "PySNMP engine version 4.4.12, Python 3.5.2 (default, Jul  5 2016, 12:43:10)  [GCC 5.4.0 20160609]"

# snmpget -v3 -u usr-md5-none -l authNoPriv -A authkey1 -n context-a 127.0.0.1 .1.3.6.1.2.1.1.1.0
iso.3.6.1.2.1.1.1.0 = STRING: "Hello World! It's currently: 2019-11-18 15:56:26.598242"

# snmpget -v3 -u usr-md5-none -l authNoPriv -A authkey1 -n context-a 127.0.0.1 .1.3.6.1.2.1.1.2.0
iso.3.6.1.2.1.1.2.0 = STRING: "You queried OID 1.3.6.1.2.1.1.2.0"

如何在MIB树中添加变量？

How to add variable in the MIB tree?

python

snmp

pysnmp

mib