This test WITHOUT encryption reveals something is majorly wrong with our packet decoding causing random and frequent disconnects.

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

@@ -73,6 +73,12 @@ public class InitialHandler extends PacketHandler implements PendingConnection
         this.ch = channel;
     }
 
+    @Override
+    public void exception(Throwable t) throws Exception
+    {
+        disconnect( ChatColor.RED + Util.exception( t ) );
+    }
+
     @Override
     public void handle(Packet1Login login) throws Exception
     {
@@ -113,7 +119,8 @@ public class InitialHandler extends PacketHandler implements PendingConnection
         Preconditions.checkArgument( handshake.username.length() <= 16, "Cannot have username longer than 16 characters" );
         this.handshake = handshake;
         ch.write( forgeMods );
-        ch.write( request = EncryptionUtil.encryptRequest() );
+        handle( (PacketCDClientStatus) null );
+        //ch.write( request = EncryptionUtil.encryptRequest() );
         thisState = State.ENCRYPT;
     }
 
@@ -195,7 +202,7 @@ public class InitialHandler extends PacketHandler implements PendingConnection
     @Override
     public void handle(PacketCDClientStatus clientStatus) throws Exception
     {
-        Preconditions.checkState( thisState == State.LOGIN, "Not expecting LOGIN" );
+        //  Preconditions.checkState( thisState == State.LOGIN, "Not expecting LOGIN" );
 
         UserConnection userCon = new UserConnection( (BungeeCord) bungee, ch, this, handshake, forgeLogin, loginMessages );
         ch.pipeline().get( HandlerBoss.class ).setHandler( new UpstreamBridge( bungee, userCon ) );

proxy/src/main/java/net/md_5/bungee/netty/CipherCodec.java

@@ -15,6 +15,7 @@ public class CipherCodec extends ByteToByteCodec
 
     private Cipher encrypt;
     private Cipher decrypt;
+    private ByteBuf heapOut;
 
     public CipherCodec(Cipher encrypt, Cipher decrypt)
     {
@@ -25,33 +26,58 @@ public class CipherCodec extends ByteToByteCodec
     @Override
     public void encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out) throws Exception
     {
-        cipher( encrypt, in, out );
+        cipher( ctx, in, out, encrypt );
     }
 
     @Override
     public void decode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out) throws Exception
     {
-        cipher( decrypt, in, out );
+        cipher( ctx, in, out, decrypt );
     }
 
-    private void cipher(Cipher cipher, ByteBuf in, ByteBuf out) throws Exception
+    @Override
+    public void freeInboundBuffer(ChannelHandlerContext ctx) throws Exception
     {
-        try
+        super.freeInboundBuffer( ctx );
+        if ( heapOut != null )
         {
+            heapOut.release();
+            heapOut = null;
+        }
+    }
+
+    @Override
+    public void freeOutboundBuffer(ChannelHandlerContext ctx) throws Exception
+    {
+        super.freeOutboundBuffer( ctx );
+        if ( heapOut != null )
+        {
+            heapOut.release();
+            heapOut = null;
+        }
+    }
+
+    private void cipher(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out, Cipher cipher) throws Exception
+    {
+        synchronized ( this )
+        {
+            if ( heapOut == null )
+            {
+                heapOut = ctx.alloc().heapBuffer();
+            }
+
             int available = in.readableBytes();
             int outputSize = cipher.getOutputSize( available );
-            int writerIndex = out.writerIndex();
+            if ( heapOut.capacity() < outputSize )
-            if ( out.capacity() + writerIndex < outputSize )
             {
-                out.capacity( outputSize + writerIndex );
+                heapOut.capacity( outputSize );
             }
-            int processed = cipher.update( in.nioBuffer(), out.nioBuffer( out.writerIndex(), outputSize ) );
+            int processed = cipher.update( in.array(), in.arrayOffset() + in.readerIndex(), available, heapOut.array(), heapOut.arrayOffset() + heapOut.writerIndex() );
             in.readerIndex( in.readerIndex() + processed );
-            out.writerIndex( writerIndex + processed );
+            heapOut.writerIndex( heapOut.writerIndex() + processed );
-        } catch ( Exception ex )
+
-        {
+            out.writeBytes( heapOut );
-            ex.printStackTrace();
+            heapOut.discardSomeReadBytes();
-            throw ex;
         }
     }
 }

proxy/src/main/java/net/md_5/bungee/netty/HandlerBoss.java

@@ -83,6 +83,10 @@ public class HandlerBoss extends ChannelInboundMessageHandlerAdapter<ByteBuf>
             {
                 ProxyServer.getInstance().getLogger().log( Level.SEVERE, handler + " - encountered exception", cause );
             }
+            if ( handler != null )
+            {
+                handler.exception( cause );
+            }
             ctx.close();
         }
     }