Improve legacy client ping support.

api/src/main/java/net/md_5/bungee/api/connection/PendingConnection.java

@@ -65,4 +65,12 @@ public interface PendingConnection extends Connection
      * Set this connection's online mode.
      */
     void setOnlineMode(boolean onlineMode);
+
+    /**
+     * Check if the client is using the older unsupported Minecraft protocol
+     * used by Minecraft clients older than 1.7.
+     *
+     * @return Whether the client is using a legacy client.
+     */
+    boolean isLegacy();
 }

protocol/src/main/java/net/md_5/bungee/protocol/LegacyDecoder.java

@@ -14,25 +14,26 @@ public class LegacyDecoder extends ByteToMessageDecoder
     @Override
     protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception
     {
-        if ( in.readableBytes() < 3 )
+        if ( !in.isReadable() )
         {
             return;
         }
-        int i = in.readerIndex();
-        short b1 = in.getUnsignedByte( i++ );
-        short b2 = in.getUnsignedByte( i++ );
-        short b3 = in.getUnsignedByte( i++ );
 
-        if ( b1 == 0xFE && b2 == 0x01 && b3 == 0xFA )
+        in.markReaderIndex();
+        short packetID = in.readUnsignedByte();
+
+        if ( packetID == 0xFE )
         {
-            out.add( new PacketWrapper( new LegacyPing(), Unpooled.EMPTY_BUFFER ) );
+            out.add( new PacketWrapper( new LegacyPing( in.isReadable() && in.readUnsignedByte() == 0x01 ), Unpooled.EMPTY_BUFFER ) );
             return;
-        }
+        } else if ( packetID == 0x02 && in.isReadable() )
-        if ( b1 == 0x02 && b2 >= 60 && b2 <= 78 )
         {
+            in.skipBytes( in.readableBytes() );
             out.add( new PacketWrapper( new LegacyHandshake(), Unpooled.EMPTY_BUFFER ) );
             return;
         }
+
+        in.resetReaderIndex();
         ctx.pipeline().remove( this );
     }
 }

protocol/src/main/java/net/md_5/bungee/protocol/packet/LegacyPing.java

@@ -1,11 +1,19 @@
 package net.md_5.bungee.protocol.packet;
 
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.RequiredArgsConstructor;
+
 import io.netty.buffer.ByteBuf;
 import net.md_5.bungee.protocol.AbstractPacketHandler;
 import net.md_5.bungee.protocol.DefinedPacket;
 
+@Data
+@RequiredArgsConstructor
+@EqualsAndHashCode(callSuper = false)
 public class LegacyPing extends DefinedPacket
 {
+    private final boolean v1_5;
 
     @Override
     public void read(ByteBuf buf)
@@ -24,23 +32,4 @@ public class LegacyPing extends DefinedPacket
     {
         handler.handle( this );
     }
-
-    @Override
-    public boolean equals(Object obj)
-    {
-        throw new UnsupportedOperationException( "Not supported yet." ); //To change body of generated methods, choose Tools | Templates.
-    }
-
-    @Override
-    public int hashCode()
-    {
-        throw new UnsupportedOperationException( "Not supported yet." ); //To change body of generated methods, choose Tools | Templates.
-    }
-
-    @Override
-    public String toString()
-    {
-        throw new UnsupportedOperationException( "Not supported yet." ); //To change body of generated methods, choose Tools | Templates.
-    }
-
 }

proxy/src/main/java/net/md_5/bungee/connection/InitialHandler.java

@@ -92,6 +92,8 @@ public class InitialHandler extends PacketHandler implements PendingConnection
     private UUID offlineId;
     @Getter
     private LoginResult loginProfile;
+    @Getter
+    private boolean legacy;
 
     private enum State
     {
@@ -125,6 +127,7 @@ public class InitialHandler extends PacketHandler implements PendingConnection
     @Override
     public void handle(LegacyHandshake legacyHandshake) throws Exception
     {
+        this.legacy = true;
         ch.getHandle().writeAndFlush( bungee.getTranslation( "outdated_client" ) );
         ch.close();
     }
@@ -132,6 +135,9 @@ public class InitialHandler extends PacketHandler implements PendingConnection
     @Override
     public void handle(LegacyPing ping) throws Exception
     {
+        this.legacy = true;
+        final boolean v1_5 = ping.isV1_5();
+
         ServerPing legacy = new ServerPing( new ServerPing.Protocol( bungee.getName() + " " + bungee.getGameVersion(), bungee.getProtocolVersion() ),
                 new ServerPing.Players( listener.getMaxPlayers(), bungee.getOnlineCount(), null ), listener.getMotd(), (Favicon) null );
 
@@ -145,14 +151,24 @@ public class InitialHandler extends PacketHandler implements PendingConnection
                     return;
                 }
 
-                ServerPing ping = result.getResponse();
+                ServerPing legacy = result.getResponse();
+                String kickMessage;
 
-                String kickMessage = ChatColor.DARK_BLUE
+                if ( v1_5 )
+                {
+                    kickMessage = ChatColor.DARK_BLUE
                             + "\00" + 127
-                        + "\00" + ping.getVersion().getName()
+                            + '\00' + legacy.getVersion().getName()
-                        + "\00" + ping.getDescription()
+                            + '\00' + getFirstLine( legacy.getDescription() )
-                        + "\00" + ping.getPlayers().getOnline()
+                            + '\00' + legacy.getPlayers().getOnline()
-                        + "\00" + ping.getPlayers().getMax();
+                            + '\00' + legacy.getPlayers().getMax();
+                } else
+                {
+                    // Clients <= 1.3 don't support colored motds because the color char is used as delimiter
+                    kickMessage = ChatColor.stripColor( getFirstLine( legacy.getDescription() ) )
+                            + '\u00a7' + legacy.getPlayers().getOnline()
+                            + '\u00a7' + legacy.getPlayers().getMax();
+                }
 
                 ch.getHandle().writeAndFlush( kickMessage );
                 ch.close();
@@ -162,6 +178,12 @@ public class InitialHandler extends PacketHandler implements PendingConnection
         bungee.getPluginManager().callEvent( new ProxyPingEvent( this, legacy, callback ) );
     }
 
+    private static String getFirstLine(String str)
+    {
+        int pos = str.indexOf( '\n' );
+        return pos == -1 ? str : str.substring( 0, pos );
+    }
+
     @Override
     public void handle(StatusRequest statusRequest) throws Exception
     {