I'm trying to develop a SNMPAgent that is able to simulate a SNMP device, using the existing snmp4j library.
public class SNMPAgent extends BaseAgent {
private String address;
/**
*
* @param address
* @throws IOException
*/
public SNMPAgent(String address) throws IOException {
/**
* Creates a base agent with boot-counter, config file, and a
* CommandProcessor for processing SNMP requests. Parameters:
* "bootCounterFile" - a file with serialized boot-counter information
* (read/write). If the file does not exist it is created on shutdown of
* the agent. "configFile" - a file with serialized configuration
* information (read/write). If the file does not exist it is created on
* shutdown of the agent. "commandProcessor" - the CommandProcessor
* instance that handles the SNMP requests.
*/
super(new File("./conf.agent"), new File("./bootCounter.agent"),
new CommandProcessor(
new OctetString(MPv3.createLocalEngineID())));
this.address = address;
}
/**
* Adds community to security name mappings needed for SNMPv1 and SNMPv2c.
*/
@Override
public void addCommunities(SnmpCommunityMIB communityMIB) {
Variable[] com2sec = new Variable[] { new OctetString("public"),
new OctetString("cpublic"), // security name
getAgent().getContextEngineID(), // local engine ID
new OctetString("public"), // default context name
new OctetString(), // transport tag
new Integer32(StorageType.nonVolatile), // storage type
new Integer32(RowStatus.active) // row status
};
MOTableRow row = communityMIB.getSnmpCommunityEntry().createRow(
new OctetString("public2public").toSubIndex(true), com2sec);
communityMIB.getSnmpCommunityEntry().addRow((SnmpCommunityMIB.SnmpCommunityEntryRow) row);
}
/**
* Adds initial notification targets and filters.
*/
@Override
protected void addNotificationTargets(SnmpTargetMIB arg0,
SnmpNotificationMIB arg1) {
// TODO Auto-generated method stub
}
/**
* Adds all the necessary initial users to the USM.
*/
@Override
protected void addUsmUser(USM arg0) {
// TODO Auto-generated method stub
}
/**
* Adds initial VACM configuration.
*/
@Override
public void addViews(VacmMIB vacm) {
vacm.addGroup(SecurityModel.SECURITY_MODEL_SNMPv2c, new OctetString(
"cpublic"), new OctetString("v1v2group"),
StorageType.nonVolatile);
vacm.addAccess(new OctetString("v1v2group"), new OctetString("public"),
SecurityModel.SECURITY_MODEL_ANY, SecurityLevel.NOAUTH_NOPRIV,
MutableVACM.VACM_MATCH_EXACT, new OctetString("fullReadView"),
new OctetString("fullWriteView"), new OctetString(
"fullNotifyView"), StorageType.nonVolatile);
vacm.addViewTreeFamily(new OctetString("fullReadView"), new OID("1.3"),
new OctetString(), VacmMIB.vacmViewIncluded,
StorageType.nonVolatile);
}
/**
* Unregister the basic MIB modules from the agent's MOServer.
*/
@Override
protected void unregisterManagedObjects() {
// TODO Auto-generated method stub
}
/**
* Register additional managed objects at the agent's server.
*/
@Override
protected void registerManagedObjects() {
// TODO Auto-generated method stub
}
protected void initTransportMappings() throws IOException {
transportMappings = new TransportMapping[1];
Address addr = GenericAddress.parse(address);
TransportMapping tm = TransportMappings.getInstance()
.createTransportMapping(addr);
transportMappings[0] = tm;
}
/**
* Start method invokes some initialization methods needed to start the
* agent
*
* @throws IOException
*/
public void start() throws IOException {
init();
// This method reads some old config from a file and causes
// unexpected behavior.
// loadConfig(ImportModes.REPLACE_CREATE);
addShutdownHook();
getServer().addContext(new OctetString("public"));
finishInit();
run();
sendColdStartNotification();
}
/**
* Clients can register the MO they need
*/
public void registerManagedObject(ManagedObject mo) {
try {
server.register(mo, null);
} catch (DuplicateRegistrationException ex) {
throw new RuntimeException(ex);
}
}
public void unregisterManagedObject(MOGroup moGroup) {
moGroup.unregisterMOs(server, getContext(moGroup));
}
}
It currently works when I try to register a new oid with a given value
SNMPAgent testAgent = new SNMPAgent(ip+"/"+port);
testAgent.start();
testAgent.unregisterManagedObject(testAgent.getSnmpv2MIB());
MOScalar editableScalar = MOCreator.createScalarEditable(new OID(oidval), new Integer32(48));
testAgent.registerManagedObject(editableScalar);
and also when I want to query the same ( and already registered ) oid
Optional<PDU> get = sender.sendGet(community, ip, port, "1.3.6.1.4.1.2011.2.1.2.1", 2, 1000L);
My trouble is that the set fuction, which should override the existing value within the oid, doesn't work. I'm using it as follows:
Integer32 intVal = new Integer32(28);
Optional<PDU> set = sender.sendSet(community, ip, port, "1.3.6.1.4.1.2011.2.1.2.1", intVal, 2, 1000L);
The sender object is instantiated from the SNMPSender class. The crucial part of the method sendSet is the following:
CommunityTarget comtarget = new CommunityTarget();
comtarget.setCommunity(new OctetString(community));
comtarget.setVersion(snmpVersion);
comtarget.setAddress(new UdpAddress(ipAddress + "/" + port));
comtarget.setRetries(retries);
comtarget.setTimeout(timeoutMillis);
PDU pdu = new PDU();
pdu.add(new VariableBinding(new OID(oidValue),setValue));
pdu.setType(PDU.SET);
ResponseEvent response = snmp.set(pdu, comtarget);
Last of all, the snmp is an object from the calss Snmp. And what does the .set method do?
public ResponseEvent set(PDU pdu, Target target) throws IOException {
pdu.setType(PDU.SET);
return send(pdu, target);
}
It calls the same send method that is called when performing a get, and even with deep debugging I can't figure out how to make it work.
We tried the SNMPSender on a real node and it worked, so I'm assuming something must be wrong with the SNMPAgent. Also when inspecting the ResponseEvent response object, the response parameter is null
