/*
OrpheusMS: MapleStory Private Server based on OdinMS
Copyright (C) 2012 Aaron Weiss <aaron@deviant-core.net>
Patrick Huy <patrick.huy@frz.cc>
Matthias Butz <matze@odinms.de>
Jan Christian Meyer <vimes@odinms.de>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero 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 Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package net.mina;
import client.MapleClient;
import tools.MapleAESOFB;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.CumulativeProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
public class MaplePacketDecoder extends CumulativeProtocolDecoder {
private static final String DECODER_STATE_KEY = MaplePacketDecoder.class.getName() + ".STATE";
private static class DecoderState {
public int packetlength = -1;
}
@Override
protected boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
final MapleClient client = (MapleClient) session.getAttribute(MapleClient.CLIENT_KEY);
DecoderState decoderState = (DecoderState) session.getAttribute(DECODER_STATE_KEY);
if (decoderState == null) {
decoderState = new DecoderState();
session.setAttribute(DECODER_STATE_KEY, decoderState);
}
if (in.remaining() >= 4 && decoderState.packetlength == -1) {
int packetHeader = in.getInt();
if (!client.getReceiveCrypto().checkPacket(packetHeader)) {
session.close(true);
return false;
}
decoderState.packetlength = MapleAESOFB.getPacketLength(packetHeader);
} else if (in.remaining() < 4 && decoderState.packetlength == -1) {
return false;
}
if (in.remaining() >= decoderState.packetlength) {
byte decryptedPacket[] = new byte[decoderState.packetlength];
in.get(decryptedPacket, 0, decoderState.packetlength);
decoderState.packetlength = -1;
client.getReceiveCrypto().crypt(decryptedPacket);
MapleCustomEncryption.decryptData(decryptedPacket);
out.write(decryptedPacket);
return true;
}
return false;
}
}