SNMPManager.java

/* 
 * Copyright 2016 christopher.metter.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package de.uniwuerzburg.info3.ofcprobe.vswitch.statistics.snmp;

import java.io.IOException;
import org.snmp4j.CommunityTarget;
import org.snmp4j.PDU;
import org.snmp4j.Snmp;
import org.snmp4j.Target;
import org.snmp4j.TransportMapping;
import org.snmp4j.event.ResponseEvent;
import org.snmp4j.mp.SnmpConstants;
import org.snmp4j.smi.Address;
import org.snmp4j.smi.GenericAddress;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.OctetString;
import org.snmp4j.smi.VariableBinding;
import org.snmp4j.transport.DefaultUdpTransportMapping;

/**
 * SNMPManager. Requests provided SNMP OID from Host.
 *
 * @author Christopher Metter(christopher.metter@informatik.uni-wuerzburg.de)
 *
 */
public class SNMPManager {

    private Snmp snmp = null;
    private String ip = null;

    /**
     * Standard Port for SNMP is 161. MUST BE PROVIDED!
     *
     * @param ip Host IP with port ip/Port eg.: 192.168.0.1/161
     */
    public SNMPManager(String ip) {
        this.ip = ip;
    }

    /**
     * Startet die SNMP Seassion.
     */
    public void start() {
        try {
            // Start SNMP Seassion
            TransportMapping<?> transport;
            transport = new DefaultUdpTransportMapping();
            this.snmp = new Snmp(transport);
            // Synchronisation
            transport.listen();
        } catch (IOException e) {
            throw new RuntimeException("Can't start SNMPManager!");
        }
    }

    /**
     * Returns the resonponse of the request
     *
     * @param oid OID.
     * @return Request.
     */
    public String getAsString(OID oid) {

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

    /**
     * Request multiple OIDs
     *
     * @param oids OIDS
     * @return ResponseEvent
     */
    public ResponseEvent get(OID oids[]) {

        try {
            PDU pdu = new PDU();
            for (OID oid : oids) {
                pdu.add(new VariableBinding(oid));
            }
            pdu.setType(PDU.GET);
            ResponseEvent event;
            event = snmp.send(pdu, getTarget(), null);
            if (event != null) {
                return event;
            }
            throw new RuntimeException("Timeout");
        } catch (IOException e) {
            throw new RuntimeException("Problem by response the OID");
        }
    }

    /**
     * Gets Target which contains information on data request Currently, SNMP 2
     * protocol 2 is used
     *
     * @return .
     */
    private Target getTarget() {

        Address targetAddress = GenericAddress.parse(this.ip);
        CommunityTarget target = new CommunityTarget();
        // Community the client has access to
        target.setCommunity(new OctetString("public"));
        target.setAddress(targetAddress);
        target.setRetries(1);
//		 Timeout (10sec)
        target.setTimeout(10000);
        // Protocol version
        target.setVersion(SnmpConstants.version2c);
        return target;
    }
}