diff --git a/utils/misc/src/main/java/org/onlab/util/Tools.java b/utils/misc/src/main/java/org/onlab/util/Tools.java
index 4a93068..61d3c56 100644
--- a/utils/misc/src/main/java/org/onlab/util/Tools.java
+++ b/utils/misc/src/main/java/org/onlab/util/Tools.java
@@ -25,6 +25,7 @@
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.FileVisitResult;
 import java.nio.file.Files;
@@ -34,9 +35,11 @@
 import java.nio.file.StandardCopyOption;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Dictionary;
 import java.util.List;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 import java.util.concurrent.ThreadFactory;
@@ -388,6 +391,37 @@
         }
     }
 
+    /**
+     * Returns a future that is completed exceptionally.
+     * @param t exception
+     * @param <T> future value type
+     * @return future
+     */
+    public static <T> CompletableFuture<T> exceptionalFuture(Throwable t) {
+        CompletableFuture<T> future = new CompletableFuture<>();
+        future.completeExceptionally(t);
+        return future;
+    }
+
+    /**
+     * Returns the contents of {@code ByteBuffer} as byte array.
+     * <p>
+     * WARNING: There is a performance cost due to array copy
+     * when using this method.
+     * @param buffer byte buffer
+     * @return byte array containing the byte buffer contents
+     */
+    public static byte[] byteBuffertoArray(ByteBuffer buffer) {
+        int length = buffer.remaining();
+        if (buffer.hasArray()) {
+            int offset = buffer.arrayOffset() + buffer.position();
+            return Arrays.copyOfRange(buffer.array(), offset, offset + length);
+        }
+        byte[] bytes = new byte[length];
+        buffer.duplicate().get(bytes);
+        return bytes;
+    }
+
     // Auxiliary path visitor for recursive directory structure copying.
     private static class DirectoryCopier extends SimpleFileVisitor<Path> {
         private Path src;
diff --git a/utils/netty/src/main/java/org/onlab/netty/NettyMessaging.java b/utils/netty/src/main/java/org/onlab/netty/NettyMessaging.java
index 44b7027..c19dc59 100644
--- a/utils/netty/src/main/java/org/onlab/netty/NettyMessaging.java
+++ b/utils/netty/src/main/java/org/onlab/netty/NettyMessaging.java
@@ -203,6 +203,25 @@
     }
 
     @Override
+    public void registerHandler(String type, Function<byte[], CompletableFuture<byte[]>> handler) {
+        handlers.put(type, message -> {
+            handler.apply(message.payload()).whenComplete((result, error) -> {
+            if (error == null) {
+                InternalMessage response = new InternalMessage(message.id(),
+                        localEp,
+                        REPLY_MESSAGE_TYPE,
+                        result);
+                try {
+                    sendAsync(message.sender(), response);
+                } catch (IOException e) {
+                    log.debug("Failed to respond", e);
+                }
+            }
+            });
+        });
+    }
+
+    @Override
     public void unregisterHandler(String type) {
         handlers.remove(type);
     }
diff --git a/utils/nio/src/main/java/org/onlab/nio/service/IOLoopMessaging.java b/utils/nio/src/main/java/org/onlab/nio/service/IOLoopMessaging.java
index 69b312a..37a6535 100644
--- a/utils/nio/src/main/java/org/onlab/nio/service/IOLoopMessaging.java
+++ b/utils/nio/src/main/java/org/onlab/nio/service/IOLoopMessaging.java
@@ -212,6 +212,23 @@
     }
 
     @Override
+    public void registerHandler(String type, Function<byte[], CompletableFuture<byte[]>> handler) {
+        handlers.put(type, message -> handler.apply(message.payload()).whenComplete((result, error) -> {
+            if (error == null) {
+                DefaultMessage response = new DefaultMessage(message.id(),
+                        localEp,
+                        REPLY_MESSAGE_TYPE,
+                        result);
+                try {
+                    sendAsync(message.sender(), response);
+                } catch (IOException e) {
+                    log.debug("Failed to respond", e);
+                }
+            }
+        }));
+    }
+
+    @Override
     public void unregisterHandler(String type) {
         handlers.remove(type);
     }
@@ -312,4 +329,4 @@
             return stream.isClosed();
         }
     }
-}
\ No newline at end of file
+}