/*
* Copyright (c) 2012 Alexander Diener,
*
* 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 de.fhkn.in.uce.holepunching.core.target;
import java.io.IOException;
import java.net.Socket;
import java.util.Set;
import java.util.UUID;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import de.fhkn.in.uce.holepunching.core.CancelableTask;
import de.fhkn.in.uce.holepunching.core.ConnectionAuthenticator;
import de.fhkn.in.uce.holepunching.core.HolePunchingUtil;
import de.fhkn.in.uce.holepunching.core.source.SourceConnectionAuthenticator;
import de.fhkn.in.uce.stun.attribute.Token;
import de.fhkn.in.uce.stun.header.STUNMessageMethod;
import de.fhkn.in.uce.stun.message.Message;
import de.fhkn.in.uce.stun.message.MessageReader;
import de.fhkn.in.uce.stun.message.MessageWriter;
/**
* Implementation of {@link ConnectionAuthenticator} on the target side.
*
* @author Daniel Maier, Alexander Diener (aldiener@htwg-konstanz.de)
*
*/
public class TargetConnectionAuthenticator implements ConnectionAuthenticator {
private static final Logger logger = LoggerFactory.getLogger(SourceConnectionAuthenticator.class);
private final HolePunchingUtil hpUtil;
private final UUID authentikationToken;
/**
* Creates a {@link TargetConnectionAuthenticator} from the given
* {@link UUID}.
*
* @param authentikationToken
* the token as {@link UUID}
*/
public TargetConnectionAuthenticator(final UUID authentikationToken) {
this.hpUtil = HolePunchingUtil.getInstance();
this.authentikationToken = authentikationToken;
}
/**
* Authentication mechanism on the target side. It first receives an
* AuthenticationMessage. If the tokens match it sends a
* AuthenticationAckMessage. Then it waits for the AuthenticationAckMessage
* from the source. If authentication is successful all hole punching
* threads get stopped.
*/
@Override
public boolean authenticate(final Socket toBeAuthenticated, final Set<CancelableTask> relatedHolePunchingTasks,
final CancelableTask ownTask, final Object sharedLock) throws IOException {
boolean result = false;
logger.info("Trying to authenticate socket: {}", toBeAuthenticated); //$NON-NLS-1$
final MessageWriter messageWriter = new MessageWriter(toBeAuthenticated.getOutputStream());
final MessageReader messageReader = this.hpUtil.getCustomHolePunchingMessageReader();
final Message receivedMessage = messageReader.readSTUNMessage(toBeAuthenticated.getInputStream());
if ((receivedMessage.getMessageMethod() == STUNMessageMethod.AUTHENTICATE)
&& receivedMessage.hasAttribute(Token.class)) {
final Token receivedToken = receivedMessage.getAttribute(Token.class);
if (receivedToken.getToken().equals(this.authentikationToken)) {
final Message tokenAckMessage = receivedMessage.buildSuccessResponse();
synchronized (sharedLock) {
messageWriter.writeMessage(tokenAckMessage);
final Message receveidAckMessage = messageReader
.readSTUNMessage(toBeAuthenticated.getInputStream());
if (this.hpUtil.isAuthenticationAcknowledgmentMessage(receveidAckMessage)) {
logger.debug("Authentication successfull, stopping hole punching threads"); //$NON-NLS-1$
this.hpUtil.stopCancableTasksExceptOwnTask(relatedHolePunchingTasks, ownTask);
result = true;
}
}
}
}
logger.debug("Authentication failed"); //$NON-NLS-1$
return result;
}
}