com.l2jmobius.gameserver.network.client.Crypt.java Source code

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Here is the source code for com.l2jmobius.gameserver.network.client.Crypt.java

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/*
 * This file is part of the L2J Mobius project.
 * 
 * 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 com.l2jmobius.gameserver.network.client;

import com.l2jmobius.commons.network.ICrypt;
import com.l2jmobius.gameserver.model.events.EventDispatcher;
import com.l2jmobius.gameserver.model.events.impl.server.OnPacketReceived;
import com.l2jmobius.gameserver.model.events.impl.server.OnPacketSent;

import io.netty.buffer.ByteBuf;

/**
 * @author UnAfraid, Nos
 */
public class Crypt implements ICrypt {
    private final L2GameClient _client;
    private final byte[] _inKey = new byte[16];
    private final byte[] _outKey = new byte[16];
    private boolean _isEnabled;

    public Crypt(L2GameClient client) {
        _client = client;
    }

    public void setKey(byte[] key) {
        System.arraycopy(key, 0, _inKey, 0, 16);
        System.arraycopy(key, 0, _outKey, 0, 16);
    }

    @Override
    public void encrypt(ByteBuf buf) {
        if (!_isEnabled) {
            _isEnabled = true;
            onPacketSent(buf);
            return;
        }

        onPacketSent(buf);

        int a = 0;
        while (buf.isReadable()) {
            final int b = buf.readByte() & 0xFF;
            a = b ^ _outKey[(buf.readerIndex() - 1) & 15] ^ a;
            buf.setByte(buf.readerIndex() - 1, a);
        }

        shiftKey(_outKey, buf.writerIndex());
    }

    @Override
    public void decrypt(ByteBuf buf) {
        if (!_isEnabled) {
            onPacketReceive(buf);
            return;
        }

        int a = 0;
        while (buf.isReadable()) {
            final int b = buf.readByte() & 0xFF;
            buf.setByte(buf.readerIndex() - 1, b ^ _inKey[(buf.readerIndex() - 1) & 15] ^ a);
            a = b;
        }

        shiftKey(_inKey, buf.writerIndex());

        onPacketReceive(buf);
    }

    private void onPacketSent(ByteBuf buf) {
        final byte[] data = new byte[buf.writerIndex()];
        buf.getBytes(0, data);
        EventDispatcher.getInstance().notifyEvent(new OnPacketSent(_client, data));
    }

    private void onPacketReceive(ByteBuf buf) {
        final byte[] data = new byte[buf.writerIndex()];
        buf.getBytes(0, data);
        EventDispatcher.getInstance().notifyEvent(new OnPacketReceived(_client, data));
    }

    private void shiftKey(byte[] key, int size) {
        int old = key[8] & 0xff;
        old |= (key[9] << 8) & 0xff00;
        old |= (key[10] << 0x10) & 0xff0000;
        old |= (key[11] << 0x18) & 0xff000000;

        old += size;

        key[8] = (byte) (old & 0xff);
        key[9] = (byte) ((old >> 0x08) & 0xff);
        key[10] = (byte) ((old >> 0x10) & 0xff);
        key[11] = (byte) ((old >> 0x18) & 0xff);
    }
}