1 files changed, 142 insertions, 0 deletions
diff --git a/examples/v3arch/asyncore/proxy/command/udp6-to-udp4-conversion.py b/examples/v3arch/asyncore/proxy/command/udp6-to-udp4-conversion.py
new file mode 100644
index 0000000..a13df6b
--- /dev/null
+++ b/examples/v3arch/asyncore/proxy/command/udp6-to-udp4-conversion.py
@@ -0,0 +1,142 @@
+"""
+IPv6-to-IPv4 conversion
++++++++++++++++++++++++
+
+Act as a local SNMPv1/v2c Agent listening on a UDP/IPv6 transport, relay
+messages to distant SNMPv1/2c Agent over UDP/IPv4 transport:
+
+* with local SNMPv2c community 'public'
+* local Agent listening at [::1]:161
+* remote SNMPv2c community 'public'
+* remote Agent listening at 195.218.195.228:161
+
+This script can be queried with the following Net-SNMP command:
+
+| $ snmpget -v2c -c public udp6:[::1]:161 sysDescr.0
+
+due to proxy, it is equivalent to
+
+| $ snmpget -v2c -c public 195.218.195.228:161 sysDescr.0
+
+Warning: for production operation you would need to modify this script
+so that it will re-map possible duplicate request-ID values, coming in
+initial request PDUs from different Managers, into unique values to
+avoid sending duplicate request-IDs to Agents.
+
+"""#
+from pysnmp.carrier.asyncore.dgram import udp, udp6
+from pysnmp.entity import engine, config
+from pysnmp.entity.rfc3413 import cmdrsp, cmdgen, context
+from pysnmp.proto.api import v2c
+from pysnmp import error
+
+# Create SNMP engine with autogenernated engineID and pre-bound
+# to socket transport dispatcher
+snmpEngine = engine.SnmpEngine()
+
+#
+# Transport setup
+#
+
+# Agent section
+
+# UDP over IPv6
+config.addTransport(
+    snmpEngine,
+    udp6.domainName,
+    udp6.Udp6Transport().openServerMode(('::1', 161))
+)
+
+# Manager section
+
+# UDP over IPv4
+config.addTransport(
+    snmpEngine,
+    udp.domainName,
+    udp.UdpTransport().openClientMode()
+)
+
+#
+# SNMPv1/2c setup (Agent role)
+#
+
+# SecurityName <-> CommunityName mapping
+config.addV1System(snmpEngine, '1-my-area', 'public')
+
+#
+# SNMPv1/v2c setup (Manager role)
+#
+# Here we configure securityName lexicographically lesser than '1-my-area'
+# to let it match first in snmpCommunityTable on response processing.
+#
+
+config.addV1System(snmpEngine, '0-distant-area', 'public',
+                   transportTag='remote')
+
+#
+# Transport target used by Manager
+#
+
+config.addTargetParams(
+    snmpEngine, 'distant-agent-auth', '0-distant-area', 'noAuthNoPriv', 1
+)
+config.addTargetAddr(
+        snmpEngine, 'distant-agent', 
+        udp.domainName, ('195.218.195.228', 161),
+        'distant-agent-auth', retryCount=0, tagList='remote'
+)
+
+# Default SNMP context
+config.addContext(snmpEngine, '')
+
+class CommandResponder(cmdrsp.CommandResponderBase):
+    cmdGenMap = { 
+        v2c.GetRequestPDU.tagSet: cmdgen.GetCommandGenerator(),
+        v2c.SetRequestPDU.tagSet: cmdgen.SetCommandGenerator(),
+        v2c.GetNextRequestPDU.tagSet: cmdgen.NextCommandGeneratorSingleRun(),
+        v2c.GetBulkRequestPDU.tagSet: cmdgen.BulkCommandGeneratorSingleRun() 
+    }
+    pduTypes = cmdGenMap.keys()  # This app will handle these PDUs
+
+    # SNMP request relay
+    def handleMgmtOperation(self, snmpEngine, stateReference, contextName,
+                            PDU, acInfo):
+        cbCtx = stateReference, PDU
+        contextEngineId = None  # address authoritative SNMP Engine
+        try:
+            self.cmdGenMap[PDU.tagSet].sendPdu(
+                snmpEngine, 'distant-agent', 
+                contextEngineId, contextName,
+                PDU,
+                self.handleResponsePdu, cbCtx
+            )
+        except error.PySnmpError:
+            self.handleResponsePdu(
+                stateReference,  'error', None, cbCtx
+            )
+
+    # SNMP response relay
+    def handleResponsePdu(self, snmpEngine, sendRequestHandle,
+                          errorIndication, PDU, cbCtx):
+        stateReference, reqPDU = cbCtx
+
+        if errorIndication:
+            PDU = v2c.apiPDU.getResponse(reqPDU)
+            PDU.setErrorStatus(PDU, 5)
+
+        self.sendPdu(
+            snmpEngine, stateReference, PDU
+        )
+
+        self.releaseStateInformation(stateReference)
+
+CommandResponder(snmpEngine, context.SnmpContext(snmpEngine))
+
+snmpEngine.transportDispatcher.jobStarted(1) # this job would never finish
+
+# Run I/O dispatcher which would receive queries and send responses
+try:
+    snmpEngine.transportDispatcher.runDispatcher()
+except:
+    snmpEngine.transportDispatcher.closeDispatcher()
+    raise