PySNMP添加自定义MIB

Question

我一直在尝试让自定义MIB工作，但没有成功。

理想情况下，我希望从ASN1源中获得MIB的完整列表，但由于失败，我尝试了多种选择。

我已经下载了IF-MIB和IANAifType-MIB，并复制了基于文本和PySNMP格式的编译版本，但似乎都没有读到。未编译.py文件。

2018-08-21 21:14:18,442 pysmi: running pysmi version 0.3.1
2018-08-21 21:14:18,442 pysmi: debug category 'searcher' enabled
2018-08-21 21:14:18,442 pysmi: debug category 'reader' enabled
2018-08-21 21:14:18,442 pysmi: debug category 'compiler' enabled
2018-08-21 21:14:19,595 pysmi: current MIB source(s): FileReader{"/usr/share/snmp/mibs"}, FileReader{"/usr/share/mibs"}
2018-08-21 21:14:19,595 pysmi: current compiled MIBs location(s): StubSearcher
2018-08-21 21:14:19,595 pysmi: current compiled MIBs location(s): StubSearcher, PyPackageSearcher{"/usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs"}, PyPackageSearcher{"/usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs/instances"}, PyPackageSearcher{"pysnmp_mibs"}
2018-08-21 21:14:19,595 pysmi: current MIB borrower(s): 
2018-08-21 21:14:20,343 pysmi: current MIB source(s): FileReader{"/usr/share/snmp/mibs"}, FileReader{"/usr/share/mibs"}
2018-08-21 21:14:20,343 pysmi: current compiled MIBs location(s): StubSearcher
2018-08-21 21:14:20,343 pysmi: current compiled MIBs location(s): StubSearcher, PyPackageSearcher{"/usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs"}, PyPackageSearcher{"/usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs/instances"}, PyPackageSearcher{"pysnmp_mibs"}
2018-08-21 21:14:20,343 pysmi: current MIB borrower(s): 
2018-08-21 21:14:22,527 pysmi: current MIB source(s): FileReader{"/usr/share/snmp/mibs"}, FileReader{"/usr/share/mibs"}
2018-08-21 21:14:22,527 pysmi: current compiled MIBs location(s): StubSearcher
2018-08-21 21:14:22,527 pysmi: current compiled MIBs location(s): StubSearcher, PyPackageSearcher{"/usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs"}, PyPackageSearcher{"/usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs/instances"}, PyPackageSearcher{"pysnmp_mibs"}
2018-08-21 21:14:22,527 pysmi: current MIB borrower(s): 


:~$ ls /usr/share/snmp/mibs/I*
/usr/share/snmp/mibs/IANA-ADDRESS-FAMILY-NUMBERS-MIB.txt
/usr/share/snmp/mibs/IANAifType-MIB
/usr/share/snmp/mibs/IANAifType-MIB.py
/usr/share/snmp/mibs/IANAifType-MIB.txt
/usr/share/snmp/mibs/IANA-LANGUAGE-MIB.txt
/usr/share/snmp/mibs/IANA-RTPROTO-MIB.txt
/usr/share/snmp/mibs/IF-MIB
/usr/share/snmp/mibs/IF-MIB.py

:~$ ls /usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs/I*     
/usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs/IANAifType-MIB.py
/usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs/IF-MIB.py
/usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs/INET-ADDRESS-MIB.py

:~$ ls /usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs/__pycache__/I*
/usr/local/lib/python3.5/dist-packages/pysnmp/smi/mibs/__pycache__/INET-ADDRESS-MIB.cpython-35.pyc

我尝试使用以下内容从snmplabs站点导入：

from pysnmp.smi import builder 

# load mibs
MIBDIR = 'http://mibs.snmplabs.com/asn1/@mib@'
mibBuilder = builder.MibBuilder()
mibSources = mibBuilder.getMibSources() + (builder.DirMibSource(MIBDIR),)
mibBuilder.setMibSources(*mibSources)

我还尝试将.addAsn1MibSource('http://mibs.snmplabs.com/asn1/@mib@')附加到cmdgen上我的OID的末尾。

我仍然得到像SNMPv2-SMI::mib-2.2.2.1.2.27 = Ethernet0/1/0.101这样的输出，而不是IF-MIB::ifDescr.27 = STRING: Ethernet0/1/0.101。我还能做些什么来找出我做错了什么？

Answer 1

尝试将.loadMibs('IF-MIB', ...)附加到传递给cmdgen的ObjectType对象。问题是，如果在没有显式引用MIB的情况下进行查询(例如使用OID)，pysnmp将不知道应该加载哪个MIB来解析响应变量。

如果您的自定义MIB是格式良好的ASN.1文档，则不需要显式地将其编译为pysnmp - pysnmp将调用pysmi为您编译MIB。

更新：

MIB只在第一次.loadMibs()调用时加载一次，并且从那时起一直保留在内存中。因此，从技术上讲，您不需要在每次迭代中重复.loadMibs()调用。

避免显式.loadMibs()的一种方法是在查询中将托管对象作为MIB和符号对而不是OID传递。这将触发隐式MIB加载。

但是这不适用于反向查找，例如，如果您遍历SNMP代理，并最终接收到属于您从未加载过的其他MIB的OID。在这种情况下，仍然建议使用.loadMibs()调用。

Answer 2

@Ilya Etingof

对不起，由于没有足够的声誉，无法回复评论................你能为上面的答案提供一个例子吗？我终于明白了

pysnmp.smi.error.SmiError: ObjectType object not fully initialized

为

ObjectType(ObjectIdentity('1.3.6.1.2.1.25.2.3').loadMibs('HOST-RESOURCES-MIB'))

到目前为止，我遵循的步骤是

from pysnmp.hlapi import ObjectIdentity, ObjectType


mibBuilder = builder.MibBuilder()
mibBuilder.addMibSources(builder.DirMibSource('C://Users//Downloads//HOST-RESOURCES-MIB.txt'))

errorIndication, errorStatus, errorIndex, \
varBindTable = cmdgen.CommandGenerator().bulkCmd(
    cmdgen.CommunityData('test'),
    cmdgen.UdpTransportTarget(('test-ip', 161)),
    0,
    1,
    ObjectType(ObjectIdentity('1.3.6.1.2.1.25.2.3').loadMibs('HOST-RESOURCES-MIB'))
)

if errorIndication:
   print(errorIndication)
else:
    if errorStatus:
        print('%s at %s\n' % (
            errorStatus.prettyPrint(),
            errorIndex and varBindTable[-1][int(errorIndex)-1] or '?'
            ))
    else:
        for varBindTableRow in varBindTable:
            for name, val in varBindTableRow:
                print('%s = %s' % (name.prettyPrint(), val.prettyPrint()))