[SNMP4J] Socket closed error in Windows 7

[varma datla]

Hello,
We are using snmp4j-1.9.3d asynchronously to find devices in a network. All is 
working well until we tested it in Windows 7 where it is throwing the  "Socket 
is closed" exception after a few seconds and stops. Even the latest version 
1.11.1 didn't seemed to work. Luckily we had an older version, snmp4j-1.9.1e, 
which is working just fine without any errors.

Here are the details. Could you please suggest any ideas on why this is 
happening on Windows 7? or if I'm not using snmp4j appropriately.


Environment:
OS- Windows 7 (Firewall is off)
SNMP4J- 1.9.3d ( also tested with 1.11.1)
JVM- 1.6.0_13 (also tested with 1.6.0_20)
Total addresses- 65025.
Exception:-
org.snmp4j.MessageException: Socket is closed
at org.snmp4j.MessageDispatcherImpl.sendPdu(Unknown Source)
at org.snmp4j.Snmp.sendMessage(Unknown Source)
at org.snmp4j.Snmp.send(Unknown Source)
at org.snmp4j.Snmp.send(Unknown Source)
at com.some.Snmp4JUtil.send(Snmp4JUtil.java:86)
at com.some.Snmp4JUtil$3.run(Snmp4JUtil.java:155)


Code:
package com.some;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.LinkedHashSet;
import java.util.Set;

import org.apache.log4j.Logger;
import org.snmp4j.CommunityTarget;
import org.snmp4j.PDU;
import org.snmp4j.Snmp;
import org.snmp4j.TimeoutModel;
import org.snmp4j.TransportMapping;
import org.snmp4j.event.ResponseEvent;
import org.snmp4j.event.ResponseListener;
import org.snmp4j.mp.SnmpConstants;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.UdpAddress;
import org.snmp4j.smi.VariableBinding;
import org.snmp4j.transport.DefaultUdpTransportMapping;

public class Snmp4JUtil
{
   private static final Logger LOGGER = Logger.getLogger( Snmp4JUtil.class );   
   
   private Snmp snmp;
   private final int [] oid = {1, 3, 6, 1, 4, 1 };
   private final ResponseListener listener;
   
   
   public Snmp4JUtil( final ResponseListener listener )
   {
      this.listener = listener;
      
      try
      {         
         final TransportMapping transport = new DefaultUdpTransportMapping();
         this.snmp = new Snmp( transport );
         snmp.setTimeoutModel( getTimeoutModel( new int[]{ 500, 1000 } ) );
         snmp.listen();
      }
      catch (IOException e)
      {
         LOGGER.error( "Snmp4JUtil(). Error: " + e.getMessage() );
      }
   }
   
   public void close()
   {
      try
      {
         snmp.close();
      }
      catch (IOException e)
      {
         LOGGER.error( "close(). Error: " + e.getMessage() );
      }
   }
   
   public void send( final CommunityTarget target )
   {
      
      final PDU pdu = new PDU();
      pdu.setType( PDU.GETNEXT );                     
      pdu.add( new VariableBinding( new OID( oid ) ) );
      
      try
      {         
         this.snmp.send( pdu, target, null, listener);
      }
      catch (IOException e)
      {
         LOGGER.error( "send( CommunityTarget ) - address:" + 
target.getAddress() + "; error:" + e.getMessage() );
         e.printStackTrace();
      }
   }
   
   private TimeoutModel getTimeoutModel( final int[] timeoutsRetries )
   {
      return new TimeoutModel()
      {
         public long getRequestTimeout( final int totalNumberOfRetries,
                                        final long targetTimeout )
         {
            long requestTimeout = 0;

            for ( int i : timeoutsRetries )
            {
               requestTimeout += i;
            }

            return requestTimeout;
         }

         public long getRetryTimeout( final int retryCount,
                                      final int totalNumberOfRetries,
                                      final long targetTimeout )
         {
            return timeoutsRetries[retryCount];
         }
      };
   }  
   
   public static void main( final String args[] )
      throws Exception
   {  
      final StringBuilder responses = new StringBuilder();
      
      final ResponseListener listener = new ResponseListener()
      {
         @Override
         public void onResponse( ResponseEvent event )
         {
            //cancel event
            ((Snmp)event.getSource()).cancel(event.getRequest(), this);
            
            // output response here.         
            responses.append( "Response: " + event.getResponse() )
               .append( System.getProperty( "line.separator" ) );
         }
      };      

      final Snmp4JUtil snmpUtil = new Snmp4JUtil( listener );
      
      // A few thousand addresses...just for testing
      final Set<String> addresses = getAddresses( args[0] );
      
      final Thread t = new Thread(){
        public void run()
        {  
           for ( final String ipAddress : addresses )
           {
              final CommunityTarget target = new CommunityTarget();             
 
              target.setAddress( new UdpAddress( ipAddress + "/161" ) );
              target.setVersion( SnmpConstants.version1 );
              target.setRetries( 1 );
              
              snmpUtil.send( target );
           }
           
           System.out.println("Done requesting..");
           
           // Wait for few more seconds for responses..just for testing.
           try
           {
              Thread.sleep( 10000 );
              
              System.out.println( "Writing response to the file.." );
              writeResponse( responses );
              
              snmpUtil.close();
              System.out.println( "Done." );
           }
           catch ( Exception e )
           {
              System.err.println( "Error while sleeping/writing: " + 
e.getMessage() );
           }
        }
      };
      
      t.start();
   }
   
   private static void writeResponse( final StringBuilder sb )
      throws Exception
   {
      final Writer output = new BufferedWriter(new FileWriter( 
"C:/responses.txt" ));
      
      try 
      {
        output.write( sb.toString() );
      }
      catch ( Exception e )
      {
        System.err.println( "Error while writing responses: " + e.getMessage() 
);
      }
      finally {
        output.close();
      }
   }
   
   private static Set<String> getAddresses( final String fileName )
      throws Exception
   {
      final Set<String> addresses = new LinkedHashSet<String>(); 
      BufferedReader input = null;
      try
      {
         input = new BufferedReader(new FileReader( fileName ) );
         
         String strLine;         
         while ((strLine = input.readLine()) != null)   
         {
            if ( strLine.trim().length() > 0 )
            {
               addresses.add( strLine );
            }
         }
         
      }catch ( Exception e )
      {
        System.err.println( "Error while reading addresses: " + e.getMessage() 
);
      }
      finally
      {
         if ( input != null )
         {
            input.close();
         }
      }
      
      return addresses;
   }
}


Thank you and I appreciate your help.

Varma