Add SNMP agent with multiple SNMP context example script

2 files changed, 87 insertions, 0 deletions

diff --git a/docs/source/examples/v3arch/asyncore/agent/cmdrsp/agent-side-mib-implementations.rst b/docs/source/examples/v3arch/asyncore/agent/cmdrsp/agent-side-mib-implementations.rst
index 67911331..c11e2ad5 100644
--- a/docs/source/examples/v3arch/asyncore/agent/cmdrsp/agent-side-mib-implementations.rst
+++ b/docs/source/examples/v3arch/asyncore/agent/cmdrsp/agent-side-mib-implementations.rst
@@ -37,6 +37,17 @@ Agent-side MIB implementations
 :download:`Download</../../examples/v3arch/asyncore/agent/cmdrsp/alternative-mib-tree.py>` script.
 
 
+.. include:: /../../examples/v3arch/asyncore/agent/cmdrsp/multiple-snmp-contexts.py
+   :start-after: """
+   :end-before: """#
+
+.. literalinclude:: /../../examples/v3arch/asyncore/agent/cmdrsp/multiple-snmp-contexts.py
+   :start-after: """#
+   :language: python
+
+:download:`Download</../../examples/v3arch/asyncore/agent/cmdrsp/multiple-snmp-contexts.py>` script.
+
+
 .. include:: /../../examples/v3arch/asyncore/agent/cmdrsp/custom-mib-controller.py
    :start-after: """
    :end-before: """#
diff --git a/examples/v3arch/asyncore/agent/cmdrsp/multiple-snmp-contexts.py b/examples/v3arch/asyncore/agent/cmdrsp/multiple-snmp-contexts.py
new file mode 100644
index 00000000..89e8db9f
--- /dev/null
+++ b/examples/v3arch/asyncore/agent/cmdrsp/multiple-snmp-contexts.py
@@ -0,0 +1,76 @@
+"""
+Multiple MIB trees under distinct context names
++++++++++++++++++++++++++++++++++++++++++++++++
+
+Listen and respond to SNMP GET/SET/GETNEXT/GETBULK queries with
+the following options:
+
+* SNMPv3
+* with USM username usr-md5-none
+* using two independent (empty) sets of Managed Objects addressed by
+  SNMP context name `context-a` and `context-b` 
+* allow access to SNMPv2-MIB objects (1.3.6.1.2.1)
+* over IPv4/UDP, listening at 127.0.0.1:161
+
+Either of the following Net-SNMP commands will walk this Agent:
+
+| $ snmpwalk -v3 -u usr-md5-none -l authNoPriv -A authkey1 -n context-a 127.0.0.1 .1.3.6
+| $ snmpwalk -v3 -u usr-md5-none -l authNoPriv -A authkey1 -n context-b 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.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