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|
"""
Implementing conceptual table
+++++++++++++++++++++++++++++
Listen and respond to SNMP GET/SET/GETNEXT/GETBULK queries with
the following options:
* SNMPv2c
* with SNMP community "public"
* define a simple SNMP Table within a newly created EXAMPLE-MIB
* pre-populate SNMP Table with a single row of values
* allow read access only to the subtree where example SNMP Table resides
* over IPv4/UDP, listening at 127.0.0.1:161
The following Net-SNMP commands will populate and walk a table:
| $ snmpset -v2c -c public 127.0.0.1 1.3.6.6.1.5.2.97.98.99 s "my value"
| $ snmpset -v2c -c public 127.0.0.1 1.3.6.6.1.5.4.97.98.99 i 4
| $ snmpwalk -v2c -c public 127.0.0.1 1.3.6
...while the following command will destroy the same row
| $ snmpset -v2c -c public 127.0.0.1 1.3.6.6.1.5.4.97.98.99 i 6
| $ snmpwalk -v2c -c public 127.0.0.1 1.3.6
"""#
from pysnmp.entity import engine, config
from pysnmp.entity.rfc3413 import cmdrsp, context
from pysnmp.carrier.asyncore.dgram import udp
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))
)
# SNMPv2c setup
# SecurityName <-> CommunityName mapping.
config.addV1System(snmpEngine, 'my-area', 'public')
# Allow read MIB access for this user / securityModels at VACM
config.addVacmUser(snmpEngine, 2, 'my-area', 'noAuthNoPriv', (1, 3, 6, 6), (1, 3, 6, 6))
# Create an SNMP context
snmpContext = context.SnmpContext(snmpEngine)
# --- define custom SNMP Table within a newly defined EXAMPLE-MIB ---
mibBuilder = snmpContext.getMibInstrum().getMibBuilder()
(MibTable,
MibTableRow,
MibTableColumn,
MibScalarInstance) = mibBuilder.importSymbols(
'SNMPv2-SMI',
'MibTable',
'MibTableRow',
'MibTableColumn',
'MibScalarInstance'
)
RowStatus, = mibBuilder.importSymbols('SNMPv2-TC', 'RowStatus')
mibBuilder.exportSymbols(
'__EXAMPLE-MIB',
# table object
exampleTable=MibTable((1, 3, 6, 6, 1)).setMaxAccess('readcreate'),
# table row object, also carries references to table indices
exampleTableEntry=MibTableRow((1, 3, 6, 6, 1, 5)).setMaxAccess('readcreate').setIndexNames((0, '__EXAMPLE-MIB', 'exampleTableColumn1')),
# table column: string index
exampleTableColumn1=MibTableColumn((1, 3, 6, 6, 1, 5, 1), v2c.OctetString()).setMaxAccess('readcreate'),
# table column: string value
exampleTableColumn2=MibTableColumn((1, 3, 6, 6, 1, 5, 2), v2c.OctetString()).setMaxAccess('readcreate'),
# table column: integer value with default
exampleTableColumn3=MibTableColumn((1, 3, 6, 6, 1, 5, 3), v2c.Integer32(123)).setMaxAccess('readcreate'),
# table column: row status
exampleTableStatus=MibTableColumn((1, 3, 6, 6, 1, 5, 4), RowStatus('notExists')).setMaxAccess('readcreate')
)
# --- end of custom SNMP table definition, empty table now exists ---
# --- populate custom SNMP table with one row ---
(exampleTableEntry,
exampleTableColumn2,
exampleTableColumn3,
exampleTableStatus) = mibBuilder.importSymbols(
'__EXAMPLE-MIB',
'exampleTableEntry',
'exampleTableColumn2',
'exampleTableColumn3',
'exampleTableStatus'
)
rowInstanceId = exampleTableEntry.getInstIdFromIndices('example record one')
mibInstrumentation = snmpContext.getMibInstrum()
mibInstrumentation.writeMibObjects(
(exampleTableColumn2.name + rowInstanceId, 'my string value'),
(exampleTableColumn3.name + rowInstanceId, 123456),
(exampleTableStatus.name + rowInstanceId, 'createAndGo')
)
# --- end of SNMP table population ---
# 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
|
