Initial Minecraft 1.9.x support

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

@@ -110,6 +110,10 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
             pingTask.cancel(false);
             pingTask = null;
         }
+
+        if (brandMessage != null) {
+            brandMessage.getData().release();
+        }
     }
 
     @Override
@@ -169,6 +173,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
 
         // Tell the server the client's brand
         if (brandMessage != null) {
+            brandMessage.getData().retain();
             player.getConnectedServer().getChannel().delayedWrite(brandMessage);
         }
 
@@ -218,12 +223,23 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
             }
 
             if (packet.getChannel().equals("MC|Brand")) {
+                if (this.brandMessage != null) {
                     // Rewrite this packet to indicate that Velocity is running. Hurrah!
                     packet = PluginMessageUtil.rewriteMCBrand(packet);
                     this.brandMessage = packet;
+                } else {
+                    // Already have the brand packet and don't need this one.
+                    return;
+                }
             }
 
             // No other special handling?
+            if (packet == original) {
+                // we'll decrement this thrice: once when writing to the server, once just below this block,
+                // and once in the MinecraftConnection (since this is a slice)
+                packet.getData().retain();
+            }
+
             player.getConnectedServer().getChannel().write(packet);
         } finally {
             ReferenceCountUtil.release(original.getData());

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

@@ -4,6 +4,10 @@ import java.util.Arrays;
 
 public enum ProtocolConstants { ;
     public static final int MINECRAFT_1_7_2 = 4;
+    public static final int MINECRAFT_1_9 = 107;
+    public static final int MINECRAFT_1_9_1 = 108;
+    public static final int MINECRAFT_1_9_2 = 109;
+    public static final int MINECRAFT_1_9_4 = 110;
     public static final int MINECRAFT_1_10 = 210;
     public static final int MINECRAFT_1_11 = 315;
     public static final int MINECRAFT_1_11_1 = 316;
@@ -11,10 +15,14 @@ public enum ProtocolConstants { ;
     public static final int MINECRAFT_1_12_1 = 338;
     public static final int MINECRAFT_1_12_2 = 340;
 
-    public static final int MINIMUM_VERSION_SUPPORTED = MINECRAFT_1_10;
+    public static final int MINIMUM_VERSION_SUPPORTED = MINECRAFT_1_9;
-    public static final int MINIMUM_GENERIC_VERSION = MINECRAFT_1_10;
+    public static final int MINIMUM_GENERIC_VERSION = MINECRAFT_1_9;
 
     public static final int[] SUPPORTED_VERSIONS = new int[] {
+            MINECRAFT_1_9,
+            MINECRAFT_1_9_1,
+            MINECRAFT_1_9_2,
+            MINECRAFT_1_9_4,
             MINECRAFT_1_10,
             MINECRAFT_1_11,
             MINECRAFT_1_11_1,

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

@@ -13,71 +13,77 @@ public enum StateRegistry {
     HANDSHAKE {
         {
             SERVERBOUND.register(Handshake.class, Handshake::new,
-                    genericMapping(0x00));
+                    genericMappings(0x00));
         }
     },
     STATUS {
         {
             SERVERBOUND.register(StatusRequest.class, StatusRequest::new,
-                    genericMapping(0x00));
+                    genericMappings(0x00));
             SERVERBOUND.register(StatusPing.class, StatusPing::new,
-                    genericMapping(0x01));
+                    genericMappings(0x01));
 
             CLIENTBOUND.register(StatusResponse.class, StatusResponse::new,
-                    genericMapping(0x00));
+                    genericMappings(0x00));
             CLIENTBOUND.register(StatusPing.class, StatusPing::new,
-                    genericMapping(0x01));
+                    genericMappings(0x01));
         }
     },
     PLAY {
         {
             SERVERBOUND.register(Chat.class, Chat::new,
-                    map(0x02, MINECRAFT_1_10),
+                    map(0x02, MINECRAFT_1_9),
                     map(0x03, MINECRAFT_1_12),
                     map(0x02, MINECRAFT_1_12_2));
             SERVERBOUND.register(ClientSettings.class, ClientSettings::new,
-                    map(0x04, MINECRAFT_1_10),
+                    map(0x04, MINECRAFT_1_9),
                     map(0x05, MINECRAFT_1_12),
                     map(0x04, MINECRAFT_1_12_1));
             SERVERBOUND.register(PluginMessage.class, PluginMessage::new,
-                    map(0x09, MINECRAFT_1_10),
+                    map(0x09, MINECRAFT_1_9),
                     map(0x0A, MINECRAFT_1_12),
                     map(0x09, MINECRAFT_1_12_1));
             SERVERBOUND.register(KeepAlive.class, KeepAlive::new,
-                    map(0x0B, MINECRAFT_1_10),
+                    map(0x0B, MINECRAFT_1_9),
                     map(0x0C, MINECRAFT_1_12),
                     map(0x0B, MINECRAFT_1_12_1));
 
             CLIENTBOUND.register(BossBar.class, BossBar::new,
-                    map(0x0C, MINECRAFT_1_10));
+                    map(0x0C, MINECRAFT_1_9),
+                    map(0x0C, MINECRAFT_1_12));
             CLIENTBOUND.register(Chat.class, Chat::new,
-                    map(0x0F, MINECRAFT_1_10));
+                    map(0x0F, MINECRAFT_1_9),
+                    map(0x0F, MINECRAFT_1_12));
             CLIENTBOUND.register(PluginMessage.class, PluginMessage::new,
-                    map(0x18, MINECRAFT_1_10));
+                    map(0x18, MINECRAFT_1_9),
+                    map(0x18, MINECRAFT_1_12));
             CLIENTBOUND.register(Disconnect.class, Disconnect::new,
-                    map(0x1A, MINECRAFT_1_10));
+                    map(0x1A, MINECRAFT_1_9),
+                    map(0x1A, MINECRAFT_1_12));
             CLIENTBOUND.register(KeepAlive.class, KeepAlive::new,
-                    map(0x1F, MINECRAFT_1_10));
+                    map(0x1F, MINECRAFT_1_9),
+                    map(0x1F, MINECRAFT_1_12));
             CLIENTBOUND.register(JoinGame.class, JoinGame::new,
-                    map(0x23, MINECRAFT_1_10));
+                    map(0x23, MINECRAFT_1_9),
+                    map(0x23, MINECRAFT_1_12));
             CLIENTBOUND.register(Respawn.class, Respawn::new,
-                    map(0x33, MINECRAFT_1_10),
+                    map(0x33, MINECRAFT_1_9),
                     map(0x34, MINECRAFT_1_12),
                     map(0x35, MINECRAFT_1_12_2));
             CLIENTBOUND.register(ScoreboardDisplay.class, ScoreboardDisplay::new,
-                    map(0x38, MINECRAFT_1_10),
+                    map(0x38, MINECRAFT_1_9),
                     map(0x3A, MINECRAFT_1_12),
                     map(0x3B, MINECRAFT_1_12_1));
             CLIENTBOUND.register(ScoreboardObjective.class, ScoreboardObjective::new,
-                    map(0x3F, MINECRAFT_1_10),
+                    map(0x3F, MINECRAFT_1_9),
                     map(0x41, MINECRAFT_1_12),
                     map(0x42, MINECRAFT_1_12_1));
             CLIENTBOUND.register(ScoreboardTeam.class, ScoreboardTeam::new,
-                    map(0x41, MINECRAFT_1_10),
+                    map(0x41, MINECRAFT_1_9),
                     map(0x43, MINECRAFT_1_12),
                     map(0x44, MINECRAFT_1_12_1));
             CLIENTBOUND.register(ScoreboardSetScore.class, ScoreboardSetScore::new,
-                    map(0x42, MINECRAFT_1_10),
+                    map(0x42, MINECRAFT_1_9),
                     map(0x44, MINECRAFT_1_12),
                     map(0x45, MINECRAFT_1_12_1));
         }
@@ -85,18 +91,18 @@ public enum StateRegistry {
     LOGIN {
         {
             SERVERBOUND.register(ServerLogin.class, ServerLogin::new,
-                    genericMapping(0x00));
+                    genericMappings(0x00));
             SERVERBOUND.register(EncryptionResponse.class, EncryptionResponse::new,
-                    genericMapping(0x01));
+                    genericMappings(0x01));
 
             CLIENTBOUND.register(Disconnect.class, Disconnect::new,
-                    genericMapping(0x00));
+                    genericMappings(0x00));
             CLIENTBOUND.register(EncryptionRequest.class, EncryptionRequest::new,
-                    genericMapping(0x01));
+                    genericMappings(0x01));
             CLIENTBOUND.register(ServerLoginSuccess.class, ServerLoginSuccess::new,
-                    genericMapping(0x02));
+                    genericMappings(0x02));
             CLIENTBOUND.register(SetCompression.class, SetCompression::new,
-                    genericMapping(0x03));
+                    genericMappings(0x03));
         }
     };
 
@@ -107,7 +113,8 @@ public enum StateRegistry {
         private static final IntObjectMap<int[]> LINKED_PROTOCOL_VERSIONS = new IntObjectHashMap<>();
 
         static {
-            LINKED_PROTOCOL_VERSIONS.put(MINECRAFT_1_10, new int[] { MINECRAFT_1_11, MINECRAFT_1_11_1, MINECRAFT_1_12 });
+            LINKED_PROTOCOL_VERSIONS.put(MINECRAFT_1_9, new int[] { MINECRAFT_1_9_1, MINECRAFT_1_9_2, MINECRAFT_1_9_4 });
+            LINKED_PROTOCOL_VERSIONS.put(MINECRAFT_1_9_4, new int[] { MINECRAFT_1_10, MINECRAFT_1_11, MINECRAFT_1_11_1 });
             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 });
         }
@@ -232,7 +239,10 @@ public enum StateRegistry {
         return new PacketMapping(id, version);
     }
 
-    private static PacketMapping genericMapping(int id) {
+    private static PacketMapping[] genericMappings(int id) {
-        return new PacketMapping(id, MINIMUM_GENERIC_VERSION);
+        return new PacketMapping[]{
+                map(id, MINECRAFT_1_9),
+                map(id, MINECRAFT_1_12)
+        };
     }
 }

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

@@ -6,8 +6,6 @@ import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
 
-import java.util.Arrays;
-
 public class PluginMessage implements MinecraftPacket {
     private String channel;
     private ByteBuf data;