Initial 1.12/1.12.1 support. Bug fixes!

src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java

@@ -4,7 +4,7 @@ import com.velocitypowered.proxy.connection.client.ClientPlaySessionHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.packets.Disconnect;
 import com.velocitypowered.proxy.protocol.packets.JoinGame;
-import com.velocitypowered.proxy.protocol.packets.Ping;
+import com.velocitypowered.proxy.protocol.packets.KeepAlive;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.packets.Respawn;
 import io.netty.buffer.ByteBuf;
@@ -18,7 +18,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
 
     @Override
     public void handle(MinecraftPacket packet) {
-        if (packet instanceof Ping) {
+        if (packet instanceof KeepAlive) {
             // Forward onto the server
             connection.getChannel().write(packet);
         } else if (packet instanceof Disconnect) {

src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -6,11 +6,13 @@ import com.velocitypowered.proxy.data.ServerInfo;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.packets.Chat;
 import com.velocitypowered.proxy.protocol.packets.JoinGame;
-import com.velocitypowered.proxy.protocol.packets.Ping;
+import com.velocitypowered.proxy.protocol.packets.KeepAlive;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.protocol.packets.Respawn;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.EventLoop;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 
 import java.net.InetSocketAddress;
 import java.util.concurrent.ScheduledFuture;
@@ -18,6 +20,8 @@ import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.TimeUnit;
 
 public class ClientPlaySessionHandler implements MinecraftSessionHandler {
+    private static final Logger logger = LogManager.getLogger(ClientPlaySessionHandler.class);
+
     private final ConnectedPlayer player;
     private ScheduledFuture<?> pingTask;
     private long lastPing = -1;
@@ -35,19 +39,19 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     }
 
     private void ping() {
-        long randomId = ThreadLocalRandom.current().nextLong();
+        long randomId = ThreadLocalRandom.current().nextInt();
         lastPing = randomId;
-        Ping ping = new Ping();
-        ping.setRandomId(randomId);
-        player.getConnection().write(ping);
+        KeepAlive keepAlive = new KeepAlive();
+        keepAlive.setRandomId(randomId);
+        player.getConnection().write(keepAlive);
     }
 
     @Override
     public void handle(MinecraftPacket packet) {
-        if (packet instanceof Ping) {
-            Ping ping = (Ping) packet;
-            if (ping.getRandomId() != lastPing) {
-                throw new IllegalStateException("Client sent invalid ping; expected " + lastPing + ", got " + ping.getRandomId());
+        if (packet instanceof KeepAlive) {
+            KeepAlive keepAlive = (KeepAlive) packet;
+            if (keepAlive.getRandomId() != lastPing) {
+                throw new IllegalStateException("Client sent invalid keepAlive; expected " + lastPing + ", got " + keepAlive.getRandomId());
             }
 
             // Do not forward the packet to the player's server, because we handle pings for all servers already.

src/main/java/com/velocitypowered/proxy/connection/client/StatusSessionHandler.java

@@ -1,20 +1,16 @@
 package com.velocitypowered.proxy.connection.client;
 
 import com.google.common.base.Preconditions;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.config.VelocityConfiguration;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
-import com.velocitypowered.proxy.protocol.packets.Ping;
+import com.velocitypowered.proxy.protocol.packets.KeepAlive;
+import com.velocitypowered.proxy.protocol.packets.StatusPing;
 import com.velocitypowered.proxy.protocol.packets.StatusRequest;
 import com.velocitypowered.proxy.protocol.packets.StatusResponse;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.data.ServerPing;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
-import net.kyori.text.Component;
-import net.kyori.text.TextComponent;
-import net.kyori.text.serializer.GsonComponentSerializer;
 
 public class StatusSessionHandler implements MinecraftSessionHandler {
     private final MinecraftConnection connection;
@@ -25,10 +21,10 @@ public class StatusSessionHandler implements MinecraftSessionHandler {
 
     @Override
     public void handle(MinecraftPacket packet) {
-        Preconditions.checkArgument(packet instanceof Ping || packet instanceof StatusRequest,
+        Preconditions.checkArgument(packet instanceof StatusPing|| packet instanceof StatusRequest,
                 "Unrecognized packet type " + packet.getClass().getName());
 
-        if (packet instanceof Ping) {
+        if (packet instanceof StatusPing) {
             // Just send back the client's packet, no processing to do here.
             connection.closeWith(packet);
             return;

src/main/java/com/velocitypowered/proxy/protocol/ProtocolConstants.java

@@ -3,10 +3,14 @@ package com.velocitypowered.proxy.protocol;
 import java.util.Arrays;
 
 public enum ProtocolConstants { ;
-    public static final int MINECRAFT_1_12 = 340;
+    public static final int MINECRAFT_1_12 = 335;
+    public static final int MINECRAFT_1_12_1 = 338;
+    public static final int MINECRAFT_1_12_2 = 340;
 
-    private static final int[] SUPPORTED_VERSIONS = new int[] {
-            MINECRAFT_1_12
+    public static final int[] SUPPORTED_VERSIONS = new int[] {
+            MINECRAFT_1_12,
+            MINECRAFT_1_12_1,
+            MINECRAFT_1_12_2
     };
 
     public static boolean isSupported(int version) {

src/main/java/com/velocitypowered/proxy/protocol/StateRegistry.java

@@ -4,67 +4,70 @@ import com.velocitypowered.proxy.protocol.packets.*;
 import io.netty.util.collection.IntObjectHashMap;
 import io.netty.util.collection.IntObjectMap;
 
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Objects;
+import java.util.*;
 import java.util.function.Supplier;
 
 import static com.velocitypowered.proxy.protocol.ProtocolConstants.MINECRAFT_1_12;
+import static com.velocitypowered.proxy.protocol.ProtocolConstants.MINECRAFT_1_12_1;
+import static com.velocitypowered.proxy.protocol.ProtocolConstants.MINECRAFT_1_12_2;
 
 public enum StateRegistry {
     HANDSHAKE {
         {
             SERVERBOUND.register(Handshake.class, Handshake::new,
-                    generic(0x00));
+                    lowestVersion(0x00));
         }
     },
     STATUS {
         {
             SERVERBOUND.register(StatusRequest.class, StatusRequest::new,
-                    generic(0x00));
-            SERVERBOUND.register(Ping.class, Ping::new,
-                    generic(0x01));
+                    lowestVersion(0x00));
+            SERVERBOUND.register(StatusPing.class, StatusPing::new,
+                    lowestVersion(0x01));
 
             CLIENTBOUND.register(StatusResponse.class, StatusResponse::new,
-                    generic(0x00));
-            CLIENTBOUND.register(Ping.class, Ping::new,
-                    generic(0x01));
+                    lowestVersion(0x00));
+            CLIENTBOUND.register(StatusPing.class, StatusPing::new,
+                    lowestVersion(0x01));
         }
     },
     PLAY {
         {
             SERVERBOUND.register(Chat.class, Chat::new,
-                    map(0x02, MINECRAFT_1_12));
-            SERVERBOUND.register(Ping.class, Ping::new,
-                    map(0x0b, MINECRAFT_1_12));
+                    map(0x03, MINECRAFT_1_12),
+                    map(0x02, MINECRAFT_1_12_2));
+            SERVERBOUND.register(KeepAlive.class, KeepAlive::new,
+                    map(0x0C, MINECRAFT_1_12),
+                    map(0x0B, MINECRAFT_1_12_1));
 
             CLIENTBOUND.register(Chat.class, Chat::new,
                     map(0x0F, MINECRAFT_1_12));
             CLIENTBOUND.register(Disconnect.class, Disconnect::new,
                     map(0x1A, MINECRAFT_1_12));
-            CLIENTBOUND.register(Ping.class, Ping::new,
+            CLIENTBOUND.register(KeepAlive.class, KeepAlive::new,
                     map(0x1F, MINECRAFT_1_12));
             CLIENTBOUND.register(JoinGame.class, JoinGame::new,
                     map(0x23, MINECRAFT_1_12));
             CLIENTBOUND.register(Respawn.class, Respawn::new,
-                    map(0x35, MINECRAFT_1_12));
+                    map(0x34, MINECRAFT_1_12),
+                    map(0x35, MINECRAFT_1_12_2));
         }
     },
     LOGIN {
         {
             SERVERBOUND.register(ServerLogin.class, ServerLogin::new,
-                    generic(0x00));
+                    lowestVersion(0x00));
             SERVERBOUND.register(EncryptionResponse.class, EncryptionResponse::new,
-                    generic(0x01));
+                    lowestVersion(0x01));
 
             CLIENTBOUND.register(Disconnect.class, Disconnect::new,
-                    generic(0x00));
+                    lowestVersion(0x00));
             CLIENTBOUND.register(EncryptionRequest.class, EncryptionRequest::new,
-                    generic(0x01));
+                    lowestVersion(0x01));
             CLIENTBOUND.register(ServerLoginSuccess.class, ServerLoginSuccess::new,
-                    generic(0x02));
+                    lowestVersion(0x02));
             CLIENTBOUND.register(SetCompression.class, SetCompression::new,
-                    generic(0x03));
+                    lowestVersion(0x03));
         }
     };
 
@@ -72,20 +75,25 @@ public enum StateRegistry {
     public final PacketRegistry SERVERBOUND = new PacketRegistry(ProtocolConstants.Direction.SERVERBOUND);
 
     public static class PacketRegistry {
+        private static final IntObjectMap<int[]> LINKED_PROTOCOL_VERSIONS = new IntObjectHashMap<>();
+
+        static {
+            LINKED_PROTOCOL_VERSIONS.put(MINECRAFT_1_12, new int[] { MINECRAFT_1_12_1 });
+            LINKED_PROTOCOL_VERSIONS.put(MINECRAFT_1_12_1, new int[] { MINECRAFT_1_12_2 });
+        }
+
         private final ProtocolConstants.Direction direction;
         private final IntObjectMap<ProtocolVersion> versions = new IntObjectHashMap<>();
 
         public PacketRegistry(ProtocolConstants.Direction direction) {
             this.direction = direction;
+            for (int version : ProtocolConstants.SUPPORTED_VERSIONS) {
+                versions.put(version, new ProtocolVersion(version));
+            }
         }
 
         public ProtocolVersion getVersion(final int version) {
-            ProtocolVersion result = null;
-            for (final IntObjectMap.PrimitiveEntry<ProtocolVersion> entry : this.versions.entries()) {
-                if (entry.key() <= version) {
-                    result = entry.value();
-                }
-            }
+            ProtocolVersion result = versions.get(version);
             if (result == null) {
                 throw new IllegalArgumentException("Could not find data for protocol version " + version);
             }
@@ -105,6 +113,17 @@ public enum StateRegistry {
                 }
                 version.packetIdToSupplier.put(mapping.id, packetSupplier);
                 version.packetClassToId.put(clazz, mapping.id);
+
+                int[] linked = LINKED_PROTOCOL_VERSIONS.get(mapping.protocolVersion);
+                if (linked != null) {
+                    links: for (int i : linked) {
+                        // Make sure that later mappings override this one.
+                        for (PacketMapping m : mappings) {
+                            if (i == m.protocolVersion) continue links;
+                        }
+                        register(clazz, packetSupplier, map(mapping.id, i));
+                    }
+                }
             }
         }
 
@@ -135,6 +154,14 @@ public enum StateRegistry {
                 }
                 return id;
             }
+
+            @Override
+            public String toString() {
+                return "ProtocolVersion{" +
+                        "id=" + id +
+                        ", packetClassToId=" + packetClassToId +
+                        '}';
+            }
         }
     }
 
@@ -174,7 +201,7 @@ public enum StateRegistry {
         return new PacketMapping(id, version);
     }
 
-    private static PacketMapping generic(int id) {
-        return new PacketMapping(id, 0);
+    private static PacketMapping lowestVersion(int id) {
+        return new PacketMapping(id, MINECRAFT_1_12);
     }
 }

src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftDecoder.java

@@ -17,6 +17,7 @@ public class MinecraftDecoder extends MessageToMessageDecoder<ByteBuf> {
     public MinecraftDecoder(ProtocolConstants.Direction direction) {
         this.state = StateRegistry.HANDSHAKE;
         this.direction = Preconditions.checkNotNull(direction, "direction");
+        this.setProtocolVersion(ProtocolConstants.MINECRAFT_1_12);
     }
 
     @Override
@@ -57,6 +58,7 @@ public class MinecraftDecoder extends MessageToMessageDecoder<ByteBuf> {
 
     public void setState(StateRegistry state) {
         this.state = state;
+        this.setProtocolVersion(protocolVersion.id);
     }
 
     public ProtocolConstants.Direction getDirection() {

src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftEncoder.java

@@ -17,6 +17,7 @@ public class MinecraftEncoder extends MessageToByteEncoder<MinecraftPacket> {
     public MinecraftEncoder(ProtocolConstants.Direction direction) {
         this.state = StateRegistry.HANDSHAKE;
         this.direction = Preconditions.checkNotNull(direction, "direction");
+        this.setProtocolVersion(ProtocolConstants.MINECRAFT_1_12);
     }
 
     @Override
@@ -40,6 +41,7 @@ public class MinecraftEncoder extends MessageToByteEncoder<MinecraftPacket> {
 
     public void setState(StateRegistry state) {
         this.state = state;
+        this.setProtocolVersion(protocolVersion.id);
     }
 
     public ProtocolConstants.Direction getDirection() {

src/main/java/com/velocitypowered/proxy/protocol/packets/KeepAlive.java

@@ -0,0 +1,45 @@
+package com.velocitypowered.proxy.protocol.packets;
+
+import com.velocitypowered.proxy.protocol.ProtocolConstants;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+
+import static com.velocitypowered.proxy.protocol.ProtocolConstants.MINECRAFT_1_12_2;
+
+public class KeepAlive implements MinecraftPacket {
+    private long randomId;
+
+    public long getRandomId() {
+        return randomId;
+    }
+
+    public void setRandomId(long randomId) {
+        this.randomId = randomId;
+    }
+
+    @Override
+    public String toString() {
+        return "KeepAlive{" +
+                "randomId=" + randomId +
+                '}';
+    }
+
+    @Override
+    public void decode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        if (protocolVersion >= MINECRAFT_1_12_2) {
+            randomId = buf.readLong();
+        } else {
+            randomId = ProtocolUtils.readVarInt(buf);
+        }
+    }
+
+    @Override
+    public void encode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        if (protocolVersion >= MINECRAFT_1_12_2) {
+            buf.writeLong(randomId);
+        } else {
+            ProtocolUtils.writeVarInt(buf, (int) randomId);
+        }
+    }
+}

src/main/java/com/velocitypowered/proxy/protocol/packets/StatusPing.java

@@ -1,27 +1,12 @@
 package com.velocitypowered.proxy.protocol.packets;
 
-import com.velocitypowered.proxy.protocol.ProtocolConstants;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolConstants;
 import io.netty.buffer.ByteBuf;
 
-public class Ping implements MinecraftPacket {
+public class StatusPing implements MinecraftPacket {
     private long randomId;
 
-    public long getRandomId() {
-        return randomId;
-    }
-
-    public void setRandomId(long randomId) {
-        this.randomId = randomId;
-    }
-
-    @Override
-    public String toString() {
-        return "Ping{" +
-                "randomId=" + randomId +
-                '}';
-    }
-
     @Override
     public void decode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
         randomId = buf.readLong();