diff --git a/src/core/open.c b/src/core/open.c
index ffcb4e29..fa9c8581 100644
--- a/src/core/open.c
+++ b/src/core/open.c
@@ -45,7 +45,7 @@ static struct socket_opener socket_openers_end[0]
 /**
  * Open URI
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v uri_string	URI string (e.g. "http://etherboot.org/kernel")
  * @ret rc		Return status code
  */
@@ -74,7 +74,7 @@ int open_uri ( struct xfer_interface *xfer, const char *uri_string ) {
 /**
  * Open socket
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v domain		Communication domain (e.g. PF_INET)
  * @v type		Communication semantics (e.g. SOCK_STREAM)
  */
@@ -101,7 +101,7 @@ int open_socket ( struct xfer_interface *xfer,
 /**
  * Open location
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v type		Location type
  * @v args		Remaining arguments depend upon location type
  * @ret rc		Return status code
@@ -128,7 +128,7 @@ int vopen ( struct xfer_interface *xfer, int type, va_list args ) {
 /**
  * Open location
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v type		Location type
  * @v ...		Remaining arguments depend upon location type
  * @ret rc		Return status code
diff --git a/src/core/xfer.c b/src/core/xfer.c
index c3993799..d3480816 100644
--- a/src/core/xfer.c
+++ b/src/core/xfer.c
@@ -26,10 +26,36 @@
  *
  */
 
+/**
+ * Close data transfer interface
+ *
+ * @v xfer		Data transfer interface
+ * @v rc		Reason for close
+ */
+void close ( struct xfer_interface *xfer, int rc ) {
+	struct xfer_interface *dest = xfer_dest ( xfer );
+
+	dest->op->close ( dest, rc );
+	xfer_unplug ( xfer );
+}
+
+/**
+ * Seek to position
+ *
+ * @v xfer		Data transfer interface
+ * @v pos		New position
+ * @ret rc		Return status code
+ */
+int seek ( struct xfer_interface *xfer, size_t pos ) {
+	struct xfer_interface *dest = xfer_dest ( xfer );
+
+	return dest->op->seek ( dest, pos );
+}
+
 /**
  * Send redirection event
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v type		New location type
  * @v args		Remaining arguments depend upon location type
  * @ret rc		Return status code
@@ -43,7 +69,7 @@ int vredirect ( struct xfer_interface *xfer, int type, va_list args ) {
 /**
  * Send redirection event
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v type		New location type
  * @v ...		Remaining arguments depend upon location type
  * @ret rc		Return status code
@@ -61,7 +87,7 @@ int redirect ( struct xfer_interface *xfer, int type, ... ) {
 /**
  * Deliver datagram
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v iobuf		Datagram I/O buffer
  * @ret rc		Return status code
  */
@@ -74,7 +100,7 @@ int deliver ( struct xfer_interface *xfer, struct io_buffer *iobuf ) {
 /**
  * Deliver datagram as raw data
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v iobuf		Datagram I/O buffer
  * @ret rc		Return status code
  */
@@ -93,10 +119,44 @@ int deliver_raw ( struct xfer_interface *xfer, const void *data, size_t len ) {
  *
  */
 
+/**
+ * Ignore close()
+ *
+ * @v xfer		Data transfer interface
+ * @v rc		Reason for close
+ */
+void ignore_close ( struct xfer_interface *xfer __unused, int rc __unused ) {
+	/* Nothing to do */
+}
+
+/**
+ * Ignore vredirect()
+ *
+ * @v xfer		Data transfer interface
+ * @v type		New location type
+ * @v args		Remaining arguments depend upon location type
+ * @ret rc		Return status code
+ */
+int ignore_vredirect ( struct xfer_interface *xfer __unused,
+		       int type __unused, va_list args __unused ) {
+	return 0;
+}
+
+/**
+ * Ignore seek()
+ *
+ * @v xfer		Data transfer interface
+ * @v pos		New position
+ * @ret rc		Return status code
+ */
+int ignore_seek ( struct xfer_interface *xfer __unused, size_t pos __unused ) {
+	return 0;
+}
+
 /**
  * Deliver datagram as raw data
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v iobuf		Datagram I/O buffer
  * @ret rc		Return status code
  *
@@ -115,7 +175,7 @@ int deliver_as_raw ( struct xfer_interface *xfer,
 /**
  * Deliver datagram as I/O buffer
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v data		Data buffer
  * @v len		Length of data buffer
  * @ret rc		Return status code
@@ -135,32 +195,29 @@ int deliver_as_iobuf ( struct xfer_interface *xfer,
 	return xfer->op->deliver ( xfer, iobuf );
 }
 
-/****************************************************************************
- *
- * Null data transfer interface
- *
- */
-
 /**
- * Null deliver datagram as raw data
+ * Ignore datagram as raw data
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v data		Data buffer
  * @v len		Length of data buffer
  * @ret rc		Return status code
  */
-static int null_deliver_raw ( struct xfer_interface *xfer,
-			      const void *data __unused, size_t len ) {
+int ignore_deliver_raw ( struct xfer_interface *xfer,
+			 const void *data __unused, size_t len ) {
 	DBGC ( xfer, "XFER %p %zd bytes delivered %s\n", xfer, len,
 	       ( ( xfer == &null_xfer ) ?
 		 "before connection" : "after termination" ) );
-	return -EPIPE;
+	return 0;
 }
 
 /** Null data transfer interface operations */
 struct xfer_interface_operations null_xfer_ops = {
+	.close		= ignore_close,
+	.vredirect	= ignore_vredirect,
+	.seek		= ignore_seek,
 	.deliver	= deliver_as_raw,
-	.deliver_raw	= null_deliver_raw,
+	.deliver_raw	= ignore_deliver_raw,
 };
 
 /**
diff --git a/src/include/gpxe/open.h b/src/include/gpxe/open.h
index 8839dc28..ad86d095 100644
--- a/src/include/gpxe/open.h
+++ b/src/include/gpxe/open.h
@@ -41,7 +41,7 @@ struct uri_opener {
 	const char *scheme;
 	/** Open URI
 	 *
-	 * @v xfer		Data-transfer interface
+	 * @v xfer		Data transfer interface
 	 * @v uri		URI
 	 * @ret rc		Return status code
 	 *
@@ -62,7 +62,7 @@ struct socket_opener {
 	int type;
 	/** Open socket
 	 *
-	 * @v xfer		Data-transfer interface
+	 * @v xfer		Data transfer interface
 	 * @v sa		Socket address
 	 * @ret rc		Return status code
 	 */
diff --git a/src/include/gpxe/xfer.h b/src/include/gpxe/xfer.h
index 0b8bf4ce..dfbde89d 100644
--- a/src/include/gpxe/xfer.h
+++ b/src/include/gpxe/xfer.h
@@ -32,22 +32,29 @@ struct xfer_interface_operations {
 
 	/** Close interface
 	 *
-	 * @v xfer		Data-transfer interface
+	 * @v xfer		Data transfer interface
 	 * @v rc		Reason for close
 	 */
 	void ( * close ) ( struct xfer_interface *xfer, int rc );
 	/** Redirect to new location
 	 *
-	 * @v xfer		Data-transfer interface
+	 * @v xfer		Data transfer interface
 	 * @v type		New location type
 	 * @v args		Remaining arguments depend upon location type
 	 * @ret rc		Return status code
 	 */
 	int ( * vredirect ) ( struct xfer_interface *xfer, int type,
 			      va_list args );
+	/** Seek to position
+	 *
+	 * @v xfer		Data transfer interface
+	 * @v pos		New position
+	 * @ret rc		Return status code
+	 */
+	int ( * seek ) ( struct xfer_interface *xfer, size_t pos );
 	/** Deliver datagram
 	 *
-	 * @v xfer		Data-transfer interface
+	 * @v xfer		Data transfer interface
 	 * @v iobuf		Datagram I/O buffer
 	 * @ret rc		Return status code
 	 *
@@ -59,7 +66,7 @@ struct xfer_interface_operations {
 			    struct io_buffer *iobuf );
 	/** Deliver datagram as raw data
 	 *
-	 * @v xfer		Data-transfer interface
+	 * @v xfer		Data transfer interface
 	 * @v data		Data buffer
 	 * @v len		Length of data buffer
 	 * @ret rc		Return status code
@@ -83,32 +90,67 @@ struct xfer_interface {
 extern struct xfer_interface null_xfer;
 extern struct xfer_interface_operations null_xfer_ops;
 
+extern void close ( struct xfer_interface *xfer, int rc );
+extern int seek ( struct xfer_interface *xfer, size_t pos );
 extern int vredirect ( struct xfer_interface *xfer, int type, va_list args );
 extern int redirect ( struct xfer_interface *xfer, int type, ... );
 extern int deliver ( struct xfer_interface *xfer, struct io_buffer *iobuf );
 extern int deliver_raw ( struct xfer_interface *xfer,
 			 const void *data, size_t len );
 
+extern void ignore_close ( struct xfer_interface *xfer, int rc );
+extern int ignore_vredirect ( struct xfer_interface *xfer,
+			      int type, va_list args );
+extern int ignore_seek ( struct xfer_interface *xfer, size_t pos );
 extern int deliver_as_raw ( struct xfer_interface *xfer,
 			    struct io_buffer *iobuf );
 extern int deliver_as_iobuf ( struct xfer_interface *xfer,
 			      const void *data, size_t len );
+extern int ignore_deliver_raw ( struct xfer_interface *xfer,
+				const void *data __unused, size_t len );
 
 /**
- * Get destination data-transfer interface
+ * Initialise a data transfer interface
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
+ * @v op		Data transfer interface operations
+ * @v refcnt		Data transfer interface reference counting method
+ */
+static inline void xfer_init ( struct xfer_interface *xfer,
+			       struct xfer_interface_operations *op,
+			       void ( * refcnt ) ( struct interface *intf,
+						   int delta ) ) {
+	xfer->intf.dest = &null_xfer.intf;
+	xfer->intf.refcnt = refcnt;
+	xfer->op = op;
+}
+
+/**
+ * Get data transfer interface from generic object communication interface
+ *
+ * @v intf		Generic object communication interface
+ * @ret xfer		Data transfer interface
+ */
+static inline struct xfer_interface *
+intf_to_xfer ( struct interface *intf ) {
+	return container_of ( intf, struct xfer_interface, intf );
+}
+
+/**
+ * Get destination data transfer interface
+ *
+ * @v xfer		Data transfer interface
  * @ret dest		Destination interface
  */
 static inline struct xfer_interface *
 xfer_dest ( struct xfer_interface *xfer ) {
-	return container_of ( xfer->intf.dest, struct xfer_interface, intf );
+	return intf_to_xfer ( xfer->intf.dest );
 }
 
 /**
- * Plug a data-transfer interface into a new destination interface
+ * Plug a data transfer interface into a new destination interface
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  * @v dest		New destination interface
  */
 static inline void xfer_plug ( struct xfer_interface *xfer,
@@ -117,23 +159,23 @@ static inline void xfer_plug ( struct xfer_interface *xfer,
 }
 
 /**
- * Unplug a data-transfer interface
+ * Unplug a data transfer interface
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  */
 static inline void xfer_unplug ( struct xfer_interface *xfer ) {
 	plug ( &xfer->intf, &null_xfer.intf );
 }
 
 /**
- * Terminate a data-transfer interface
+ * Stop using a data transfer interface
  *
- * @v xfer		Data-transfer interface
+ * @v xfer		Data transfer interface
  *
  * After calling this method, no further messages will be received via
  * the interface.
  */
-static inline void xfer_terminate ( struct xfer_interface *xfer ) {
+static inline void xfer_nullify ( struct xfer_interface *xfer ) {
 	xfer->op = &null_xfer_ops;
 };