[SNMP4J] Strange problem with multithreaded SNMPv3-Scan

[chk-world at gmx.de]

In-Reply-To=24557.1099935606 at www13.gmx.net

Hi Frank and Mathias,
thanks for your reply to my question. I tried to set the tcp and udp buffer
size and file-max value to the following on my linux system:

sysctl -w net.core.wmem_max=524287 (was 128k)
sysctl -w net.core.rmem_max=524287 (was 128k)
sysctl -w net.core.wmem_default=524287 (was 64k)
sysctl -w net.core.rmem_default=524287 (was 64k)
sysctl -w net.core.optmem_max=20480 (was 10k)
fs.file-max = 91750 (was that high allready)

This doesn't change anything. Also setting to low values doesn't brought
more errors.

> As Mathias already pointed out, increasing the UDP buffer size on your
> system may help. Without knowing more about your request sending
> code, it is hard to help more specific.
I attached an example at the end of this message.
If I run more than 4 Threads at the same time I get response = null back
when doing response=snmp.sendPDU(request, uTarget) from agents who answer
correctly if using only 4 Threads.

When playing with some timeout values sometimes I get:
org.snmp4j.MessageException: Message processing model 3 returned error:
-1402

Best regards and thanks,
Chris

PS: I'm using a webmailer, so the In-Reply-To doens't get set in the mail,
sorry for that.

----------------------------
import java.io.IOException;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.snmp4j.*;
import EDU.oswego.cs.dl.util.concurrent.LinkedQueue;
import EDU.oswego.cs.dl.util.concurrent.PooledExecutor;

public class SNMPv3DeviceDiscovery
{
  private class RunnableSender implements Runnable
  {
    public static final int DEFAULT = 0;
    
    String ipAddress = null;
    OID authProtocol;
    OID privProtocol;
    OctetString privPassphrase;
    OctetString authPassphrase;
    OctetString authoritativeEngineID;
    OctetString contextEngineID;
    OctetString contextName = new OctetString();
    OctetString securityName = new OctetString();

    int version = SnmpConstants.version3;
    int retries = 1;
    int timeout = 1500;
    int pduType = PDU.GET;

    VariableBinding variableBinding;
    int operation = DEFAULT;
    Snmp snmp;
    USM usm = null;
    PDU response = null;
    PDU request = null;
    UserTarget uTarget;

    /* unchanged from SnmpRequest from
       org/snmp4j/tools/console/SnmpRequest.java */
    private void printVariableBindings(PDU response) {...}
    private void printReport(PDU response) {...}
    
    private RunnableSender(String ipAddress)
    {
      this.ipAddress = ipAddress;
      variableBinding = new VariableBinding(new OID("1.3.6.1.2.1.1.5.0"));
      authProtocol = AuthMD5.ID;
      securityName = new OctetString("user");
      authPassphrase = new OctetString("authPwd");
      privPassphrase = new OctetString("privPwd");
      version = SnmpConstants.version3;
      privProtocol = PrivDES.ID;

      uTarget = new UserTarget();
      uTarget.setSecurityLevel(SecurityLevel.AUTH_PRIV);
      uTarget.setSecurityName(securityName);
      uTarget.setVersion(version);
      uTarget.setRetries(retries);
      uTarget.setTimeout(timeout);
      uTarget.setAddress(new UdpAddress(ipAddress + "/161"));

      request = new ScopedPDU();
      request.setType(pduType);
      request.add(variableBinding);
    }

    public void run()
    {
      try
      {
        DefaultUdpTransportMapping dutm = new DefaultUdpTransportMapping();
        dutm.setAsyncMsgProcessingSupported(false);
        TransportMapping transport = dutm;
        
        snmp = new Snmp(transport);
        usm = new USM(SecurityProtocols.getInstance(), new
OctetString(((MPv3) snmp
           
.getMessageProcessingModel(MessageProcessingModel.MPv3)).createLocalEngineID()),
0);
        SecurityModels.getInstance().addSecurityModel(usm);
        snmp.getUSM().addUser(securityName,
            new UsmUser(securityName, authProtocol, authPassphrase,
privProtocol, privPassphrase));
        snmp.listen();
      } catch (IOException e1)
      {
        e1.printStackTrace();
      }

      try
      {
        response = snmp.sendPDU(request, uTarget);
      } catch (IOException e)
      {
        e.printStackTrace();
      } // catch

      if (response == null)
      {
        System.out.print("host: " + ipAddress + " --- ");
        System.out.println("Request timed out.");
      } else if (response.getType() == PDU.REPORT)
      {
        System.out.print("host: " + ipAddress + " --- ");
        printReport(response);
      } else
      {
        System.out.println("Response received with requestID=" +
response.getRequestID() + ", errorIndex="
            + response.getErrorIndex() + ", " + "errorStatus=" +
response.getErrorStatus());
        System.out.print("host: " + ipAddress + " --- ");
        printVariableBindings(response);
      } // if response
      close();
    } // run
    
 public void close() {
  try {
      SecurityModels.getInstance().removeSecurityModel(new
Integer32(usm.getID()));
        usm = null;
        snmp.close();
      } catch (IOException e2) {
        e2.printStackTrace();
      }
    }
  } // RunnableSender

 public void ipLoop() throws InterruptedException
 {
  // the second parameter is the maxPoolSize, if this value (and the
  // minPoolSize are bigger than 4 I get timeouts.
  PooledExecutor pooledExecutor = new PooledExecutor(new LinkedQueue(), 4);
  pooledExecutor.setMinimumPoolSize(4);
   
  for (int i = 1; i < 10; i++)
  {
    pooledExecutor.execute(new RunnableSender("10.137.1." +
Integer.toString(i)));
  }//for
 }//ipLoop

  public static void main(String[] args) throws InterruptedException{
    Logger.getRootLogger().setLevel(Level.OFF);
    CounterSupport.getInstance().addCounterListener(new
DefaultCounterListener());
    SNMPv3DeviceDiscovery snmpRequest = new SNMPv3DeviceDiscovery();
    snmpRequest.ipLoop();
    Thread.sleep(20000);
    System.exit(0);
  }
}

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