/*******************************************************************************
* gMix open source project - https://svs.informatik.uni-hamburg.de/gmix/
* Copyright (C) 2014 SVS
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*******************************************************************************/
package userGeneratedContent.testbedPlugIns.layerPlugIns.layer3outputStrategy.binomialPool_v0_001;
import java.security.SecureRandom;
import java.util.Vector;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.apache.commons.math.MathException;
import org.apache.commons.math.distribution.NormalDistributionImpl;
import staticContent.framework.controller.Implementation;
import staticContent.framework.interfaces.Layer3OutputStrategyMix;
import staticContent.framework.message.MixMessage;
import staticContent.framework.message.Reply;
import staticContent.framework.message.Request;
import staticContent.framework.userDatabase.User;
//Diaz 2003 ("Generalising Mixes")
//"a timed pool mix that tosses coins and uses a probability function that
//depends on the number of messages inside the mix at the time of flushing"
//-> normal cumulative distribution
public class MixPlugIn extends Implementation implements Layer3OutputStrategyMix {
private static SecureRandom secureRandom = new SecureRandom();
private SimplexBinomialPool requestPool;
private SimplexBinomialPool replyPool;
private int DEFAULT_POOL_SIZE;
private int SENDING_RATE;
private double MAX_OUTPUT_FRACTION;
private double MEAN;
private double STDDEV;
@Override
public void constructor() {
this.DEFAULT_POOL_SIZE = settings.getPropertyAsInt("BINOMIAL_POOL_DEFAULT_POOL_SIZE");
this.SENDING_RATE = settings.getPropertyAsInt("BINOMIAL_POOL_SENDING_RATE");
this.MAX_OUTPUT_FRACTION = settings.getPropertyAsDouble("BINOMIAL_POOL_MAX_OUTPUT_FRACTION");
this.MEAN = settings.getPropertyAsDouble("BINOMIAL_POOL_MEAN");
this.STDDEV = settings.getPropertyAsDouble("BINOMIAL_POOL_STDDEV");
this.requestPool = new SimplexBinomialPool(true);
this.replyPool = new SimplexBinomialPool(false);
}
@Override
public void initialize() {
// no need to do anything
}
@Override
public void begin() {
// no need to do anything
}
@Override
public void addRequest(Request request) {
requestPool.addMessage((MixMessage) request);
}
@Override
public void addReply(Reply reply) {
replyPool.addMessage((MixMessage) reply);
}
public class SimplexBinomialPool implements Runnable {
private boolean isRequestPool;
private Vector<MixMessage> collectedMessages;
private boolean isFirstMessage = true;
private NormalDistributionImpl normalDist;
private ScheduledThreadPoolExecutor scheduler;
public SimplexBinomialPool( boolean isRequestPool) {
this.collectedMessages = new Vector<MixMessage>(DEFAULT_POOL_SIZE);
this.isRequestPool = isRequestPool;
this.scheduler = new ScheduledThreadPoolExecutor(1);
this.normalDist = new NormalDistributionImpl(MEAN, STDDEV);
this.normalDist.reseedRandomGenerator(secureRandom.nextLong());
}
public void addMessage(MixMessage mixMessage) {
synchronized (this) {
if (isFirstMessage) {
isFirstMessage = false;
scheduler.scheduleAtFixedRate(this, SENDING_RATE, SENDING_RATE, TimeUnit.MILLISECONDS);
}
collectedMessages.add(mixMessage);
}
}
public void putOutMessages() {
synchronized (this) {
try {
double coinBias = MAX_OUTPUT_FRACTION * normalDist.cumulativeProbability(collectedMessages.size());
for (int i=0; i<collectedMessages.size(); i++) {
MixMessage m = collectedMessages.get(i);
if (secureRandom.nextDouble() <= coinBias) {
if (isRequestPool)
anonNode.putOutRequest((Request)m);
else
anonNode.putOutReply((Reply)m);
collectedMessages.remove(i--);
}
}
} catch (MathException e) {
throw new RuntimeException("ERROR: problem with generating the biased coin! " +e.getStackTrace());
}
}
}
@Override
public void run() {
putOutMessages();
}
}
@Override
public int getMaxSizeOfNextWrite() {
return super.recodingLayerMix.getMaxSizeOfNextReply();
}
@Override
public int getMaxSizeOfNextRead() {
return super.recodingLayerMix.getMaxSizeOfNextRequest();
}
@Override
public void write(User user, byte[] data) {
Reply reply = MixMessage.getInstanceReply(data, user);
reply.isFirstReplyHop = true;
transportLayerMix.addLayer4Header(reply);
anonNode.forwardToLayer2(reply);
}
}