/*
* 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.mediator;
import java.io.OutputStream;
import java.net.Inet6Address;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.nio.ByteBuffer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import de.fhkn.in.uce.holepunching.message.HolePunchingAttribute;
import de.fhkn.in.uce.mediator.connectionhandling.ConnectionRequest;
import de.fhkn.in.uce.mediator.connectionhandling.ConnectionRequestList;
import de.fhkn.in.uce.mediator.peerregistry.UserData;
import de.fhkn.in.uce.mediator.peerregistry.UserList;
import de.fhkn.in.uce.mediator.util.MediatorUtil;
import de.fhkn.in.uce.plugininterface.mediator.HandleMessage;
import de.fhkn.in.uce.plugininterface.message.NATTraversalTechniqueAttribute;
import de.fhkn.in.uce.stun.attribute.ErrorCode.STUNErrorCode;
import de.fhkn.in.uce.stun.attribute.Token;
import de.fhkn.in.uce.stun.attribute.Username;
import de.fhkn.in.uce.stun.attribute.XorMappedAddress;
import de.fhkn.in.uce.stun.header.STUNMessageClass;
import de.fhkn.in.uce.stun.header.STUNMessageMethod;
import de.fhkn.in.uce.stun.message.Message;
import de.fhkn.in.uce.stun.message.MessageStaticFactory;
/**
* This custom handler handles connection request messages for hole punching. It
* calls the target which starts the hole punching target and returns the
* private endpoint. The handler sends the private and public endpoints of the
* peers to the other party.
*
* @author Alexander Diener (aldiener@htwg-konstanz.de)
*
*/
public final class HolePunchingConnRequestHandler implements HandleMessage {
private static final Logger logger = LoggerFactory.getLogger(HolePunchingConnRequestHandler.class);
private final ConnectionRequestList connectionRequests = ConnectionRequestList.INSTANCE;
private final MediatorUtil mediatorUtil = MediatorUtil.INSTANCE;
private final UserList userList = UserList.INSTANCE;
@Override
public void handleMessage(final Message message, final Socket controlConnection) throws Exception {
if (message.getMessageClass() == STUNMessageClass.REQUEST) {
logger.debug("Handling connection request from {}", controlConnection.toString());
this.handleConnectionRequest(message, controlConnection);
} else if (message.getMessageClass() == STUNMessageClass.SUCCESS_RESPONSE) {
logger.debug("Handling connection request response from {}", controlConnection.toString());
this.handleConnectionRequestResponse(message, controlConnection);
}
}
private void handleConnectionRequest(final Message message, final Socket controlConnection) throws Exception {
this.mediatorUtil.checkForAttribute(message, Username.class);
this.mediatorUtil.checkForAttribute(message, XorMappedAddress.class);
this.connectionRequests.putConnectionRequest(new ConnectionRequest(controlConnection, message));
final Username username = message.getAttribute(Username.class);
final UserData user = this.userList.getUserDataByUserId(username.getUsernameAsString());
if (user == null) {
final String errorMessage = "User " + username.getUsernameAsString() + " not exists"; //$NON-NLS-1$ //$NON-NLS-2$
this.sendFailureResponse(message, errorMessage, STUNErrorCode.BAD_REQUEST,
controlConnection.getOutputStream());
} else {
this.forwardConnectionRequest(user, message, controlConnection);
// this.sendHPMessagesToPeers(user, message, controlConnection);
}
}
private void handleConnectionRequestResponse(final Message message, final Socket controlConnection)
throws Exception {
final ConnectionRequest connReq = this.connectionRequests.getConnectionRequest(new String(message.getHeader()
.getTransactionId()));
final Message successResponse = connReq.getConnectionRequestMessage().buildSuccessResponse();
// public endpoint
successResponse.addAttribute(this.createXorMappedAddressFromSocket(controlConnection, successResponse
.getHeader().getTransactionId()));
// private endpoint
successResponse.addAttribute(message.getAttribute(XorMappedAddress.class));
logger.debug("Sending connection request response to {}", connReq.getControlConnection().toString()); //$NON-NLS-1$
successResponse.writeTo(connReq.getControlConnection().getOutputStream());
}
private void forwardConnectionRequest(final UserData target, final Message connectionRequestFromSource,
final Socket controlConnectionToSource) throws Exception {
final Socket toTarget = target.getSocketToUser();
final Message connectionRequest = MessageStaticFactory.newSTUNMessageInstance(STUNMessageClass.REQUEST,
STUNMessageMethod.CONNECTION_REQUEST, connectionRequestFromSource.getHeader().getTransactionId());
connectionRequest.addAttribute(new HolePunchingAttribute());
connectionRequest.addAttribute(connectionRequestFromSource.getAttribute(Token.class));
// public endpoint
connectionRequest.addAttribute(this.createXorMappedAddressFromSocket(controlConnectionToSource,
connectionRequest.getHeader().getTransactionId()));
// private endpoint
connectionRequest.addAttribute(connectionRequestFromSource.getAttribute(XorMappedAddress.class));
logger.debug("Forwarding endpoints to target {}", toTarget.toString()); //$NON-NLS-1$
connectionRequest.writeTo(toTarget.getOutputStream());
}
private void sendFailureResponse(final Message message, final String errorReaon, final STUNErrorCode errorCode,
final OutputStream out) throws Exception {
logger.debug(errorReaon);
final Message failureResponse = message.buildFailureResponse(errorCode, errorReaon);
failureResponse.writeTo(out);
}
private XorMappedAddress createXorMappedAddressFromSocket(final Socket socket, final byte[] transactionid) {
XorMappedAddress result;
if (socket.getInetAddress() instanceof Inet6Address) {
result = new XorMappedAddress(new InetSocketAddress(socket.getInetAddress(), socket.getPort()), ByteBuffer
.wrap(transactionid).getInt());
} else {
result = new XorMappedAddress(new InetSocketAddress(socket.getInetAddress(), socket.getPort()));
}
return result;
}
@Override
public NATTraversalTechniqueAttribute getAttributeForTraversalTechnique() {
return new HolePunchingAttribute();
}
}