hostage/src/de/tudarmstadt/informatik/hostage/ConnectionGuard.java

package de.tudarmstadt.informatik.hostage;

import android.util.Log;


public class ConnectionGuard {

	private final static ConnectionGuard INSTANCE = new ConnectionGuard();

	private ConnectionGuard() {
	}

	public final static long ONE_SECOND_IN_NANOSECONDS = 1000000000;

	private static long lastTimestamp = 0;
	private static String lastIP = "";
	private static String lastProtocol = "";

	public synchronized static boolean registerConnection(String protocol, String ip) {
		long timestamp = System.nanoTime();		
		boolean result = detectedPortscan(protocol, ip, timestamp);
		lastTimestamp = timestamp;
		lastIP = ip;
		lastProtocol = protocol;
		return result;
	}
	
	public synchronized static boolean detectedPortscan(String protocol, String ip){
		return detectedPortscan(protocol, ip, System.nanoTime());
	}
	
	public synchronized static boolean detectedPortscan(String protocol, String ip, long timestamp) {
		boolean result = false;
		boolean firstConnection = (lastTimestamp == 0);
		boolean belowThreshold = ((timestamp - lastTimestamp) < ONE_SECOND_IN_NANOSECONDS);
		boolean sameIP = (lastIP.equals(ip));
		boolean sameProtocol = (lastProtocol.equals(protocol));
		if (!firstConnection && sameIP && belowThreshold && !sameProtocol) {
			result = true;
		}
		
		return result;
	}
}