Geyser/connector/src/main/java/org/geysermc/connector/ping/GeyserLegacyPingPassthrough.java

/*
 * Copyright (c) 2019-2020 GeyserMC. http://geysermc.org
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a copy
 *  of this software and associated documentation files (the "Software"), to deal
 *  in the Software without restriction, including without limitation the rights
 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the Software is
 *  furnished to do so, subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in
 *  all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *  THE SOFTWARE.
 *
 *  @author GeyserMC
 *  @link https://github.com/GeyserMC/Geyser
 *
 */

package org.geysermc.connector.ping;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.github.steveice10.mc.protocol.MinecraftConstants;
import com.nukkitx.nbt.util.VarInts;
import org.geysermc.connector.common.ping.GeyserPingInfo;
import org.geysermc.connector.GeyserConnector;

import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ConnectException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketTimeoutException;
import java.util.concurrent.TimeUnit;

public class GeyserLegacyPingPassthrough implements IGeyserPingPassthrough, Runnable {

    private GeyserConnector connector;

    public GeyserLegacyPingPassthrough(GeyserConnector connector) {
        this.connector = connector;
    }

    private GeyserPingInfo pingInfo;

    /**
     * Start legacy ping passthrough thread
     * @param connector GeyserConnector
     * @return GeyserPingPassthrough, or null if not initialized
     */
    public static IGeyserPingPassthrough init(GeyserConnector connector) {
        if (connector.getConfig().isPassthroughMotd() || connector.getConfig().isPassthroughPlayerCounts()) {
            GeyserLegacyPingPassthrough pingPassthrough = new GeyserLegacyPingPassthrough(connector);
            // Ensure delay is not zero
            int interval = (connector.getConfig().getPingPassthroughInterval() == 0) ? 1 : connector.getConfig().getPingPassthroughInterval();
            connector.getLogger().debug("Scheduling ping passthrough at an interval of " + interval + " second(s).");
            connector.getGeneralThreadPool().scheduleAtFixedRate(pingPassthrough, 1, interval, TimeUnit.SECONDS);
            return pingPassthrough;
        }
        return null;
    }

    @Override
    public GeyserPingInfo getPingInformation() {
        return pingInfo;
    }

    @Override
    public void run() {
        try {
            Socket socket = new Socket();
            String address = connector.getConfig().getRemote().getAddress();
            int port = connector.getConfig().getRemote().getPort();
            socket.connect(new InetSocketAddress(address, port), 5000);

            ByteArrayOutputStream byteArrayStream = new ByteArrayOutputStream();
            DataOutputStream handshake = new DataOutputStream(byteArrayStream);
            handshake.write(0x0);
            VarInts.writeUnsignedInt(handshake, MinecraftConstants.PROTOCOL_VERSION);
            VarInts.writeUnsignedInt(handshake, address.length());
            handshake.writeBytes(address);
            handshake.writeShort(port);
            VarInts.writeUnsignedInt(handshake, 1);

            DataOutputStream dataOutputStream = new DataOutputStream(socket.getOutputStream());
            VarInts.writeUnsignedInt(dataOutputStream, byteArrayStream.size());
            dataOutputStream.write(byteArrayStream.toByteArray());
            dataOutputStream.writeByte(0x01);
            dataOutputStream.writeByte(0x00);

            DataInputStream dataInputStream = new DataInputStream(socket.getInputStream());
            VarInts.readUnsignedInt(dataInputStream);
            VarInts.readUnsignedInt(dataInputStream);
            int length = VarInts.readUnsignedInt(dataInputStream);
            byte[] buffer = new byte[length];
            dataInputStream.readFully(buffer);
            dataOutputStream.writeByte(0x09);
            dataOutputStream.writeByte(0x01);
            dataOutputStream.writeLong(System.currentTimeMillis());

            VarInts.readUnsignedInt(dataInputStream);
            String json = new String(buffer);

            this.pingInfo = GeyserConnector.JSON_MAPPER.readValue(json, GeyserPingInfo.class);

            byteArrayStream.close();
            handshake.close();
            dataOutputStream.close();
            dataInputStream.close();
            socket.close();
        } catch (SocketTimeoutException | ConnectException ex) {
            this.pingInfo = null;
            this.connector.getLogger().debug("Connection timeout for ping passthrough.");
        } catch (JsonParseException | JsonMappingException ex) {
            this.connector.getLogger().error("Failed to parse json when pinging server!", ex);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}