SNMPManager.java

package org.opennaas.extensions.gim.controller.snmp;

import java.io.IOException;

import org.snmp4j.CommunityTarget;
import org.snmp4j.PDU;
import org.snmp4j.ScopedPDU;
import org.snmp4j.Snmp;
import org.snmp4j.Target;
import org.snmp4j.TransportMapping;
import org.snmp4j.UserTarget;
import org.snmp4j.event.ResponseEvent;
import org.snmp4j.mp.MPv3;
import org.snmp4j.mp.SnmpConstants;
import org.snmp4j.security.AuthMD5;
import org.snmp4j.security.SecurityLevel;
import org.snmp4j.security.SecurityModels;
import org.snmp4j.security.SecurityProtocols;
import org.snmp4j.security.USM;
import org.snmp4j.security.UsmUser;
import org.snmp4j.smi.Address;
import org.snmp4j.smi.GenericAddress;
import org.snmp4j.smi.Integer32;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.OctetString;
import org.snmp4j.smi.VariableBinding;
import org.snmp4j.transport.DefaultUdpTransportMapping;

public class SNMPManager {
	Snmp	snmp				= null;
	String	address				= null;

	int		SNMPversion			= 3;

	String	ver3Username		= "apc1";
	String	ver3AuthPasscode	= "admin user phrase";

	/**
	 * Constructor
	 * 
	 * @param add
	 */

	public SNMPManager(String add)
	{
		address = add;
	}

	/**
	 * Start the Snmp session. If you forget the listen() method you will not get any answers because the communication is asynchronous and the
	 * listen() method listens for answers.
	 * 
	 * @throws IOException
	 */

	public void start() throws IOException {
		TransportMapping transport = new DefaultUdpTransportMapping();

		if (SNMPversion == 3) {
			USM usm = new USM(SecurityProtocols.getInstance(), new OctetString(MPv3.createLocalEngineID()), 0);
			SecurityModels.getInstance().addSecurityModel(usm);
		}
		snmp = new Snmp(transport);

		if (SNMPversion == 3)
			snmp.getUSM().addUser(new OctetString(ver3Username),
					new UsmUser(new OctetString(ver3Username), AuthMD5.ID, new OctetString(ver3AuthPasscode), null, null));

		// Do not forget this line!
		transport.listen();
	}

	/**
	 * Method which takes a single OID and returns the response from the agent as a String.
	 * 
	 * @param oid
	 * @return
	 * @throws IOException
	 */

	public String getAsString(OID oid) throws IOException {
		ResponseEvent event = get(new OID[] { oid });
		return event.getResponse().get(0).getVariable().toString();
	}

	public String setIntFromString(int value, OID oid) throws IOException {

		ResponseEvent event = set(new OID[] { oid }, value);

		return event.getResponse().get(0).getVariable().toString();

	}

	public ResponseEvent set(OID oids[], int value) throws IOException {

		PDU pdu;

		if (SNMPversion == 3)
			pdu = new ScopedPDU();
		else
			pdu = new PDU();

		for (OID oid : oids) {
			pdu.add(new VariableBinding(oid, new Integer32(value)));
		}

		pdu.setType(PDU.SET);
		ResponseEvent event = null;

		try {
			if (SNMPversion == 3)
				event = snmp.send(pdu, getSNMPv3Target(), null);
			else
				event = snmp.send(pdu, getTarget(), null);

		} catch (IOException ioe) {
			System.out.println("Error SNMP SET");
		}

		if (event != null) {
			return event;
		}
		throw new RuntimeException("SET timed out");
	}

	/**
	 * This method is capable of handling multiple OIDs
	 * 
	 * @param oids
	 * @return
	 * @throws IOException
	 */

	public ResponseEvent get(OID oids[]) throws IOException {
		PDU pdu;

		if (SNMPversion == 3)
			pdu = new ScopedPDU();
		else
			pdu = new PDU();

		for (OID oid : oids) {
			pdu.add(new VariableBinding(oid));
		}

		pdu.setType(PDU.GET);

		ResponseEvent response;

		if (SNMPversion == 3)
			response = snmp.send(pdu, getSNMPv3Target());
		else
			response = snmp.send(pdu, getTarget());

		if (response != null) {
			PDU responsePDU = response.getResponse();
			if (responsePDU != null) {
				if (responsePDU.getErrorStatus() == PDU.noError) {
					return response;
				}
			}
			throw new RuntimeException("reposne was null");
		}
		throw new RuntimeException("GET timed out");
	}

	/**
	 * This method returns a Target, which contains information about where the data should be fetched and how.
	 * 
	 * @return
	 */

	private Target getSNMPv3Target() {
		Address targetAddress = GenericAddress.parse(address);
		UserTarget target = new UserTarget();

		target.setAddress(targetAddress);

		target.setVersion(SnmpConstants.version3); // SnmpConstants.version3
		target.setRetries(2);
		target.setTimeout(2500);
		target.setSecurityLevel(SecurityLevel.AUTH_NOPRIV); // SecurityLevel.AUTH_NOPRIV
		target.setSecurityName(new OctetString(ver3Username));

		return target;
	}

	private Target getTarget() {

		Address targetAddress = GenericAddress.parse(address);
		CommunityTarget target = new CommunityTarget();

		target.setCommunity(new OctetString("public"));

		target.setAddress(targetAddress);

		target.setRetries(2);

		target.setTimeout(1500);

		target.setVersion(SnmpConstants.version2c);

		return target;
	}

}