diff --git a/src/core/posix_io.c b/src/core/posix_io.c
index 31db8665..f4ae1c13 100644
--- a/src/core/posix_io.c
+++ b/src/core/posix_io.c
@@ -141,10 +141,13 @@ static int posix_file_xfer_seek ( struct xfer_interface *xfer, off_t offset,
  *
  * @v xfer		POSIX file data transfer interface
  * @v iobuf		I/O buffer
+ * @v meta		Data transfer metadata, or NULL
  * @ret rc		Return status code
  */
-static int posix_file_xfer_deliver_iob ( struct xfer_interface *xfer,
-					 struct io_buffer *iobuf ) {
+static int
+posix_file_xfer_deliver_iob ( struct xfer_interface *xfer,
+			      struct io_buffer *iobuf,
+			      struct xfer_metadata *meta __unused ) {
 	struct posix_file *file =
 		container_of ( xfer, struct posix_file, xfer );
 
diff --git a/src/core/xfer.c b/src/core/xfer.c
index ea5fda3d..97fd2a62 100644
--- a/src/core/xfer.c
+++ b/src/core/xfer.c
@@ -174,20 +174,23 @@ struct io_buffer * xfer_alloc_iob ( struct xfer_interface *xfer, size_t len ) {
 }
 
 /**
- * Deliver datagram
+ * Deliver datagram as I/O buffer with metadata
  *
  * @v xfer		Data transfer interface
  * @v iobuf		Datagram I/O buffer
+ * @v meta		Data transfer metadata, or NULL
  * @ret rc		Return status code
  */
-int xfer_deliver_iob ( struct xfer_interface *xfer, struct io_buffer *iobuf ) {
+int xfer_deliver_iob_meta ( struct xfer_interface *xfer,
+			    struct io_buffer *iobuf,
+			    struct xfer_metadata *meta ) {
 	struct xfer_interface *dest = xfer_get_dest ( xfer );
 	int rc;
 
 	DBGC ( xfer, "XFER %p->%p deliver_iob %zd\n", xfer, dest,
 	       iob_len ( iobuf ) );
 
-	rc = dest->op->deliver_iob ( dest, iobuf );
+	rc = dest->op->deliver_iob ( dest, iobuf, meta );
 
 	if ( rc != 0 ) {
 		DBGC ( xfer, "XFER %p<-%p deliver_iob: %s\n", xfer, dest,
@@ -197,6 +200,18 @@ int xfer_deliver_iob ( struct xfer_interface *xfer, struct io_buffer *iobuf ) {
 	return rc;
 }
 
+/**
+ * Deliver datagram as I/O buffer with metadata
+ *
+ * @v xfer		Data transfer interface
+ * @v iobuf		Datagram I/O buffer
+ * @ret rc		Return status code
+ */
+int xfer_deliver_iob ( struct xfer_interface *xfer,
+		       struct io_buffer *iobuf ) {
+	return xfer_deliver_iob_meta ( xfer, iobuf, NULL );
+}
+
 /**
  * Deliver datagram as raw data
  *
@@ -341,13 +356,15 @@ default_xfer_alloc_iob ( struct xfer_interface *xfer __unused, size_t len ) {
  *
  * @v xfer		Data transfer interface
  * @v iobuf		Datagram I/O buffer
+ * @v meta		Data transfer metadata
  * @ret rc		Return status code
  *
  * This function is intended to be used as the deliver() method for
  * data transfer interfaces that prefer to handle raw data.
  */
 int xfer_deliver_as_raw ( struct xfer_interface *xfer,
-			  struct io_buffer *iobuf ) {
+			  struct io_buffer *iobuf,
+			  struct xfer_metadata *meta __unused ) {
 	int rc;
 
 	rc = xfer->op->deliver_raw ( xfer, iobuf->data, iob_len ( iobuf ) );
@@ -375,7 +392,7 @@ int xfer_deliver_as_iob ( struct xfer_interface *xfer,
 		return -ENOMEM;
 
 	memcpy ( iob_put ( iobuf, len ), data, len );
-	return xfer->op->deliver_iob ( xfer, iobuf );
+	return xfer->op->deliver_iob ( xfer, iobuf, NULL );
 }
 
 /**
diff --git a/src/include/gpxe/xfer.h b/src/include/gpxe/xfer.h
index f946ab1c..0224613b 100644
--- a/src/include/gpxe/xfer.h
+++ b/src/include/gpxe/xfer.h
@@ -13,6 +13,7 @@
 #include <gpxe/iobuf.h>
 
 struct xfer_interface;
+struct xfer_metadata;
 
 /** Data transfer interface operations */
 struct xfer_interface_operations {
@@ -63,10 +64,11 @@ struct xfer_interface_operations {
 	 */
 	struct io_buffer * ( * alloc_iob ) ( struct xfer_interface *xfer,
 					     size_t len );
-	/** Deliver datagram as I/O buffer
+	/** Deliver datagram as I/O buffer with metadata
 	 *
 	 * @v xfer		Data transfer interface
 	 * @v iobuf		Datagram I/O buffer
+	 * @v meta		Data transfer metadata, or NULL
 	 * @ret rc		Return status code
 	 *
 	 * A data transfer interface that wishes to support only raw
@@ -78,7 +80,8 @@ struct xfer_interface_operations {
 	 * fatal error.
 	 */
 	int ( * deliver_iob ) ( struct xfer_interface *xfer,
-				struct io_buffer *iobuf );
+				struct io_buffer *iobuf,
+				struct xfer_metadata *meta );
 	/** Deliver datagram as raw data
 	 *
 	 * @v xfer		Data transfer interface
@@ -106,6 +109,14 @@ struct xfer_interface {
 	struct xfer_interface_operations *op;
 };
 
+/** Data transfer metadata */
+struct xfer_metadata {
+	/** Source socket address, or NULL */
+	struct sockaddr *src;
+	/** Destination socket address, or NULL */
+	struct sockaddr *dest;
+};
+
 /** Basis positions for seek() events */
 enum seek_whence {
 	SEEK_SET = 0,
@@ -141,6 +152,9 @@ extern struct io_buffer * xfer_alloc_iob ( struct xfer_interface *xfer,
 					   size_t len );
 extern int xfer_deliver_iob ( struct xfer_interface *xfer,
 			      struct io_buffer *iobuf );
+extern int xfer_deliver_iob_meta ( struct xfer_interface *xfer,
+				   struct io_buffer *iobuf,
+				   struct xfer_metadata *meta );
 extern int xfer_deliver_raw ( struct xfer_interface *xfer,
 			      const void *data, size_t len );
 extern int xfer_vprintf ( struct xfer_interface *xfer,
@@ -158,7 +172,8 @@ extern int ignore_xfer_seek ( struct xfer_interface *xfer, off_t offset,
 extern struct io_buffer * default_xfer_alloc_iob ( struct xfer_interface *xfer,
 						   size_t len );
 extern int xfer_deliver_as_raw ( struct xfer_interface *xfer,
-				 struct io_buffer *iobuf );
+				 struct io_buffer *iobuf,
+				 struct xfer_metadata *meta );
 extern int xfer_deliver_as_iob ( struct xfer_interface *xfer,
 				 const void *data, size_t len );
 extern int ignore_xfer_deliver_raw ( struct xfer_interface *xfer,
diff --git a/src/net/tcp.c b/src/net/tcp.c
index 830e8d50..00c7b742 100644
--- a/src/net/tcp.c
+++ b/src/net/tcp.c
@@ -930,10 +930,12 @@ static int tcp_xfer_seek ( struct xfer_interface *xfer, off_t offset,
  *
  * @v xfer		Data transfer interface
  * @v iobuf		Datagram I/O buffer
+ * @v meta		Data transfer metadata, or NULL
  * @ret rc		Return status code
  */
 static int tcp_xfer_deliver_iob ( struct xfer_interface *xfer,
-				  struct io_buffer *iobuf ) {
+				  struct io_buffer *iobuf,
+				  struct xfer_metadata *meta __unused ) {
 	struct tcp_connection *tcp =
 		container_of ( xfer, struct tcp_connection, xfer );
 
diff --git a/src/net/tcp/ftp.c b/src/net/tcp/ftp.c
index f90e7931..b027d912 100644
--- a/src/net/tcp/ftp.c
+++ b/src/net/tcp/ftp.c
@@ -338,10 +338,12 @@ static void ftp_data_closed ( struct xfer_interface *data, int rc ) {
  *
  * @v xfer		FTP data channel interface
  * @v iobuf		I/O buffer
+ * @v meta		Data transfer metadata, or NULL
  * @ret rc		Return status code
  */
 static int ftp_data_deliver_iob ( struct xfer_interface *data,
-				  struct io_buffer *iobuf ) {
+				  struct io_buffer *iobuf,
+				  struct xfer_metadata *meta __unused ) {
 	struct ftp_request *ftp =
 		container_of ( data, struct ftp_request, data );
 	int rc;
diff --git a/src/net/tcp/http.c b/src/net/tcp/http.c
index cdd6fb91..dcd0d3a3 100644
--- a/src/net/tcp/http.c
+++ b/src/net/tcp/http.c
@@ -316,10 +316,12 @@ static int http_rx_data ( struct http_request *http,
  *
  * @v socket		Transport layer interface
  * @v iobuf		I/O buffer
+ * @v meta		Data transfer metadata, or NULL
  * @ret rc		Return status code
  */
 static int http_socket_deliver_iob ( struct xfer_interface *socket,
-				     struct io_buffer *iobuf ) {
+				     struct io_buffer *iobuf,
+				     struct xfer_metadata *meta __unused ) {
 	struct http_request *http =
 		container_of ( socket, struct http_request, socket );
 	struct http_line_handler *lh;