/* $Id: snmptrapforwarder.src,v 1.4 2002/04/11 13:28:31 tonyjpaul Exp $*/
/*
 * @(#)snmptrapforwarder.src
 * Copyright (c) 2012 ZOHO Corp. All Rights Reserved.
 * Please read the associated COPYRIGHTS file for more details.
 */

import com.adventnet.snmp.snmp2.*;
import java.util.*;
import ParseOptions;
import java.net.InetAddress;

public class snmptrapforwarder extends Thread implements SnmpClient {
    SnmpAPI api;
    SnmpSession v3_session;
    Vector v;
    String remoteHost = "localhost";
    int remotePort = 2001;
    int local_port=162;
    private static final int DEBUG_FLAG = 0;

    snmptrapforwarder()
    {
        // Start SNMP API
        api = new SnmpAPI();

        try {
            Thread.sleep(500);
        } catch (Exception x) {} 

        // Open session and set remote host & port if needed,
        v3_session = new SnmpSession(api);
        v = new Vector();
    }

    public static void main(String args[]) {

	if (args.length!= 3){
		System.out.println("Usage : java snmptrapforwarder [LocalPort] [RemoteHost] [RemotePort]");
		System.exit(1);
	}
    snmptrapforwarder eserv = new snmptrapforwarder();

    // Take care of getting options

	//String[] hostname={""};
	//eserv.v3_session.setLocalAddresses(hostname);
    eserv.local_port=Integer.parseInt(args[0]);
    eserv.v3_session.setLocalPort(eserv.local_port);
//     eserv.api.setDebug( true );

    eserv.remotePort = Integer.parseInt(args[2]);
	eserv.v3_session.setRemotePort(eserv.remotePort);
	eserv.remoteHost=args[1];

    try {
        eserv.v3_session.open();
    } catch (SnmpException e) {
	System.out.println("Unable to start session: " + e);
	System.exit(1);
	}

    eserv.v3_session.addSnmpClient(eserv);
    eserv.start();
     } // end main()

    public boolean authenticate(SnmpPDU pdu, String community)
    {
        	return true;
    }

    public boolean callback(SnmpSession sess, SnmpPDU pdu, int reqID)
    {
        if (pdu == null)
        {
            System.err.println("Null PDU received");
        }
        enQ(pdu);

        return true;
    }

        public void debugPrint(String debugOutput)
    {
        return;
    }


    /** Print octet data in a more readable form */
    String printOctets(byte[] data, int length) {
    StringBuffer s = new StringBuffer();

    int j = 0, line = 20; // we'll allow 20 bytes per line
    if (data.length < length) length = data.length;

    for (int i=0;i<length;i++) {
        if (j++ > 19) { j=1; s.append("\n"); }
        String bs = Integer.toString(byteToInt(data[i]),16);
        if (bs.length() < 2) bs = "0" + bs;
        s.append(bs+ " ");
    }
    return s.toString();
    }

    public synchronized SnmpPDU deQ()
    {
        for (Enumeration e = v.elements() ; e.hasMoreElements() ;)
        {
                SnmpPDU pdu = (SnmpPDU) e.nextElement();
            v.removeElement(pdu);
            return pdu;
        }
        return null;
    }
    
    /** Place in specified queue */
    public synchronized void enQ(SnmpPDU pdu)
    {
        v.addElement(pdu);
        notifyAll();
    }

    public void run()
    {
        System.out.println("snmptrapforwarder: Ready to forward traps");
        while (true)
        {
            SnmpPDU pdu = deQ();

            if (pdu == null)
                wait_for_v3pdus();

            if (pdu == null)
                pdu = deQ();

            if (pdu == null)
                continue;

            try {
					if ((pdu.getCommand() == SnmpAPI.TRP_REQ_MSG) 
							||(pdu.getCommand() == SnmpAPI.TRP2_REQ_MSG)
					)
				{
						pdu.setRemotePort(remotePort);
						pdu.setRemoteHost(remoteHost);
						System.out.println("Trap is Forwarded to "+remoteHost+":"+remotePort);
                		v3_session.send(pdu);
					}
					else
					{
						System.out.println("Not a Trap PDU -- dropping");
					}
            } catch (SnmpException e) {
                    System.err.println("Sending  PDU" + e.getMessage());
                continue;
            }

        }
    }

    public synchronized void wait_for_v3pdus()
    {
        try {
            if (v.size() > 0)
                return;
            else
                wait();
        } catch (InterruptedException i) {}
    }
    
    static int byteToInt(byte b) 
        {
          return (int)b & 0xFF;
        }
    
}