diff --git a/src/include/gpxe/hello.h b/src/include/gpxe/hello.h
new file mode 100644
index 00000000..23ee336f
--- /dev/null
+++ b/src/include/gpxe/hello.h
@@ -0,0 +1,46 @@
+#ifndef _HELLO_H
+#define _HELLO_H
+
+/** @file
+ *
+ * "Hello world" TCP protocol
+ *
+ */
+
+#include <stdint.h>
+#include <gpxe/tcp.h>
+
+enum hello_state {
+	HELLO_SENDING_MESSAGE = 1,
+	HELLO_SENDING_ENDL,
+};
+
+/**
+ * A "hello world" request
+ *
+ */
+struct hello_request {
+	/** TCP connection for this request */
+	struct tcp_connection tcp;
+	/** Current state */
+	enum hello_state state;
+	/** Message to be transmitted */
+	const char *message;
+	/** Amount of message remaining to be transmitted */
+	size_t remaining;
+	/** Callback function
+	 *
+	 * @v data	Received data
+	 * @v len	Length of received data
+	 *
+	 * This function is called for all data received from the
+	 * remote server.
+	 */
+	void ( *callback ) ( char *data, size_t len );
+	/** Connection complete indicator */
+	int complete;
+};
+
+extern int hello_connect ( struct hello_request *hello );
+
+#endif
diff --git a/src/proto/hello.c b/src/proto/hello.c
new file mode 100644
index 00000000..eee9c77b
--- /dev/null
+++ b/src/proto/hello.c
@@ -0,0 +1,133 @@
+#include <stddef.h>
+#include <string.h>
+#include <vsprintf.h>
+#include <assert.h>
+#include <gpxe/hello.h>
+
+/** @file
+ *
+ * "Hello world" TCP protocol
+ *
+ * This file implements a trivial TCP-based protocol.  It connects to
+ * the server specified in hello_request::tcp and transmits a single
+ * message (hello_request::message).  Any data received from the
+ * server will be passed to the callback function,
+ * hello_request::callback(), and once the connection has been closed,
+ * hello_request::complete will be set to 1.
+ *
+ * To use this code, do something like:
+ *
+ * @code
+ *
+ *   static void my_callback ( char *data, size_t len ) {
+ *     ... process data ...
+ *   }
+ *
+ *   struct hello_request hello = {
+ *     .message = "hello world!",
+ *     .callback = my_callback,
+ *   };
+ *
+ *   hello.sin.sin_addr.s_addr = ... server IP address ...
+ *   hello.sin.sin_port = ... server port ...
+ *
+ *   hello_connect ( &hello );
+ *   while ( ! hello.completed ) {
+ *     run_tcpip();
+ *   }
+ *
+ * @endcode
+ *
+ * It's worth noting that this trivial protocol would be entirely
+ * adequate to implement a TCP-based version of TFTP; just use "RRQ
+ * <filename>" as the message.  Now, if only an appropriate server
+ * existed...
+ */
+
+static inline struct hello_request *
+tcp_to_hello ( struct tcp_connection *conn ) {
+	return container_of ( conn, struct hello_request, tcp );
+}
+
+static void hello_aborted ( struct tcp_connection *conn ) {
+	struct hello_request *hello = tcp_to_hello ( conn );
+
+	printf ( "Connection aborted\n" );
+	hello->complete = 1;
+}
+
+static void hello_timedout ( struct tcp_connection *conn ) {
+	struct hello_request *hello = tcp_to_hello ( conn );
+
+	printf ( "Connection timed out\n" );
+	hello->complete = 1;
+}
+
+static void hello_closed ( struct tcp_connection *conn ) {
+	struct hello_request *hello = tcp_to_hello ( conn );
+
+	hello->complete = 1;
+}
+
+static void hello_connected ( struct tcp_connection *conn ) {
+	struct hello_request *hello = tcp_to_hello ( conn );
+
+	hello->remaining = strlen ( hello->message );
+	hello->state = HELLO_SENDING_MESSAGE;
+}
+
+static void hello_acked ( struct tcp_connection *conn, size_t len ) {
+	struct hello_request *hello = tcp_to_hello ( conn );
+	
+	hello->message += len;
+	hello->remaining -= len;
+	if ( hello->remaining == 0 ) {
+		switch ( hello->state ) {
+		case HELLO_SENDING_MESSAGE:
+			hello->message = "\r\n";
+			hello->remaining = 2;
+			hello->state = HELLO_SENDING_ENDL;
+			break;
+		case HELLO_SENDING_ENDL:
+			/* Nothing to do once we've finished sending
+			 * the end-of-line indicator.
+			 */
+			break;
+		default:
+			assert ( 0 );
+		}
+	}
+}
+
+static void hello_newdata ( struct tcp_connection *conn, void *data,
+			    size_t len ) {
+	struct hello_request *hello = tcp_to_hello ( conn );
+
+	hello->callback ( data, len );
+}
+
+static void hello_senddata ( struct tcp_connection *conn ) {
+	struct hello_request *hello = tcp_to_hello ( conn );
+
+	tcp_send ( conn, hello->message, hello->remaining );
+}
+
+static struct tcp_operations hello_tcp_operations = {
+	.aborted	= hello_aborted,
+	.timedout	= hello_timedout,
+	.closed		= hello_closed,
+	.connected	= hello_connected,
+	.acked		= hello_acked,
+	.newdata	= hello_newdata,
+	.senddata	= hello_senddata,
+};
+
+/**
+ * Initiate a "hello world" connection
+ *
+ * @v hello	"Hello world" request
+ */
+int hello_connect ( struct hello_request *hello ) {
+	hello->tcp.tcp_op = &hello_tcp_operations;
+	return tcp_connect ( &hello->tcp );
+}
diff --git a/src/util/prototester.c b/src/util/prototester.c
index f520d668..d5cd91fd 100644
--- a/src/util/prototester.c
+++ b/src/util/prototester.c
@@ -12,6 +12,7 @@
 #include <assert.h>
 
 #include <gpxe/tcp.h>
+#include <gpxe/hello.h>
 
 typedef int irq_action_t;
 
@@ -251,109 +252,6 @@ static void hijack_disable ( struct hijack_device *hijack_dev ) {
  *
  */
 
-#include <stddef.h>
-#define container_of(ptr, type, member) ({                      \
-	const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
-	(type *)( (char *)__mptr - offsetof(type,member) );})
-
-enum hello_state {
-	HELLO_SENDING_MESSAGE = 1,
-	HELLO_SENDING_ENDL,
-};
-
-struct hello_request {
-	struct tcp_connection tcp;
-	const char *message;
-	enum hello_state state;
-	size_t remaining;
-	void ( *callback ) ( char *data, size_t len );
-	int complete;
-};
-
-static inline struct hello_request *
-tcp_to_hello ( struct tcp_connection *conn ) {
-	return container_of ( conn, struct hello_request, tcp );
-}
-
-static void hello_aborted ( struct tcp_connection *conn ) {
-	struct hello_request *hello = tcp_to_hello ( conn );
-
-	printf ( "Connection aborted\n" );
-	hello->complete = 1;
-}
-
-static void hello_timedout ( struct tcp_connection *conn ) {
-	struct hello_request *hello = tcp_to_hello ( conn );
-
-	printf ( "Connection timed out\n" );
-	hello->complete = 1;
-}
-
-static void hello_closed ( struct tcp_connection *conn ) {
-	struct hello_request *hello = tcp_to_hello ( conn );
-
-	hello->complete = 1;
-}
-
-static void hello_connected ( struct tcp_connection *conn ) {
-	struct hello_request *hello = tcp_to_hello ( conn );
-
-	printf ( "Connection established\n" );
-	hello->state = HELLO_SENDING_MESSAGE;
-}
-
-static void hello_acked ( struct tcp_connection *conn, size_t len ) {
-	struct hello_request *hello = tcp_to_hello ( conn );
-
-	hello->message += len;
-	hello->remaining -= len;
-	if ( hello->remaining == 0 ) {
-		switch ( hello->state ) {
-		case HELLO_SENDING_MESSAGE:
-			hello->state = HELLO_SENDING_ENDL;
-			hello->message = "\r\n";
-			hello->remaining = 2;
-			break;
-		case HELLO_SENDING_ENDL:
-			/* Nothing to do once we've finished sending
-			 * the end-of-line indicator.
-			 */
-			break;
-		default:
-			assert ( 0 );
-		}
-	}
-}
-
-static void hello_newdata ( struct tcp_connection *conn, void *data,
-			    size_t len ) {
-	struct hello_request *hello = tcp_to_hello ( conn );
-
-	hello->callback ( data, len );
-}
-
-static void hello_senddata ( struct tcp_connection *conn ) {
-	struct hello_request *hello = tcp_to_hello ( conn );
-
-	tcp_send ( conn, hello->message, hello->remaining );
-}
-
-static struct tcp_operations hello_tcp_operations = {
-	.aborted	= hello_aborted,
-	.timedout	= hello_timedout,
-	.closed		= hello_closed,
-	.connected	= hello_connected,
-	.acked		= hello_acked,
-	.newdata	= hello_newdata,
-	.senddata	= hello_senddata,
-};
-
-static int hello_connect ( struct hello_request *hello ) {
-	hello->tcp.tcp_op = &hello_tcp_operations;
-	hello->remaining = strlen ( hello->message );
-	return tcp_connect ( &hello->tcp );
-}
-
 struct hello_options {
 	struct sockaddr_in server;
 	const char *message;