Trying to stop packets to a particular IP address

[Annie Rajoria]

I have been trying to develop an application to stop packets from reaching a particular IP address. However I am getting the following 2 errors:

1) Multiple markers at this line
- The left-hand side of an assignment must be a
variable - Syntax error on token ".0", invalid AssignmentOperator
for targetIp = 0.0.0.0; (I have changed it from String as I need to compare it later on to DestinationIP)

2) Multiple markers at this line
- Syntax error on token "p", delete this
token - Packet cannot be resolved to a variable
for line: getLayerHandler().getTransportLayer().receive(Packet p, sourceIP, destinationIP);

The code(modified of Simpleportscanner application) to get the above result is:

public class nnew extends IPApplication
{

public nnew()
{
    srcport = 1;
    destport = 1024;
    targetIp = 0.0.0.0;
    originIp = "1.1.1.1";
    startTick = 100;
}

public void handleEvent(Event e)
{
        getLayerHandler().getTransportLayer().receive(Packet p, sourceIP, destinationIP);

        if(destinationIP==targetIp){
            return;
        }
        else{
            Random ran = new Random(123L);

                byte payload[] = new byte[28];
                ran.nextBytes(payload);
                getLayerHandler().getTransportLayer().sendUDPPacket(srcport, destport, destinationIP, payload);
            }

    super.handleEvent(e);
}

public boolean start()
{
    //destinationIP = IPFactory.createIPv4Address(targetIp);
    TickedEvent e = new TickedEvent(this, startTick);
    getLayerHandler().addEvent(e);
    return super.start();
}

private int srcport;
private int destport;
//private String targetIp;
private String originIp;
private int startTick;
private IPv4Address destinationIP,targetIp;
private IPv4Address sourceIP;

}

Kindly help! Thank you!

[Karsten Bsufka]

Well this are standard Java implementation error and actual the errors messages already point to the solution, e.g.: getLayerHandler().getTransportLayer().receive(Packet p, sourceIP, destinationIP); ==> getLayerHandler().getTransportLayer().receive(p, sourceIP, destinationIP);

Which still would not work since there is no p anywhere in that method.

NeSSi2 already ships with a few example applications, one is a firewall. You could us that implementation as a hint, see de.dailab.nessi.applications.firewall.FirewallApp. This is located in:

    <groupId>de.dailab.nessi</groupId>
    <artifactId>nessi.ip.applications</artifactId>

Hope that helps.