Make seek information part of the xfer metadata, rather than an entirely

separate xfer method.

Add missing .alloc_iob entries to several xfer_interface_operations
structures.

18 files changed, 83 insertions, 165 deletions

diff --git a/src/core/downloader.c b/src/core/downloader.c
index 3726c6e..0a443db 100644
--- a/src/core/downloader.c
+++ b/src/core/downloader.c
@@ -96,6 +96,9 @@ static int downloader_ensure_size ( struct downloader *downloader,
 	if ( len <= downloader->image->len )
 		return 0;
 
+	DBGC ( downloader, "Downloader %p extending to %zd bytes\n",
+	       downloader, len );
+
 	/* Extend buffer */
 	new_buffer = urealloc ( downloader->image->data, len );
 	if ( ! new_buffer ) {
@@ -142,67 +145,43 @@ static struct job_interface_operations downloader_job_operations = {
  */
 
 /**
- * Handle seek() event received via data transfer interface
- *
- * @v xfer		Downloader data transfer interface
- * @v pos		New position
- * @ret rc		Return status code
- */
-static int downloader_xfer_seek ( struct xfer_interface *xfer, off_t offset,
-				  int whence ) {
-	struct downloader *downloader =
-		container_of ( xfer, struct downloader, xfer );
-	off_t new_pos;
-	int rc;
-
-	/* Calculate new buffer position */
-	switch ( whence ) {
-	case SEEK_SET:
-		new_pos = offset;
-		break;
-	case SEEK_CUR:
-		new_pos = ( downloader->pos + offset );
-		break;
-	default:
-		assert ( 0 );
-		return -EINVAL;
-	}
-
-	/* Ensure that we have enough buffer space for this buffer position */
-	if ( ( rc = downloader_ensure_size ( downloader, new_pos ) ) != 0 )
-		return rc;
-	downloader->pos = new_pos;
-
-	return 0;
-}
-
-/**
  * Handle deliver_raw() event received via data transfer interface
  *
  * @v xfer		Downloader data transfer interface
- * @v data		Data buffer
- * @v len		Length of data buffer
+ * @v iobuf		Datagram I/O buffer
+ * @v meta		Data transfer metadata
  * @ret rc		Return status code
  */
-static int downloader_xfer_deliver_raw ( struct xfer_interface *xfer,
-					 const void *data, size_t len ) {
+static int downloader_xfer_deliver_iob ( struct xfer_interface *xfer,
+					 struct io_buffer *iobuf,
+					 struct xfer_metadata *meta ) {
 	struct downloader *downloader =
 		container_of ( xfer, struct downloader, xfer );
+	size_t len;
 	size_t max;
 	int rc;
 
+	/* Calculate new buffer position */
+	if ( meta->whence != SEEK_CUR )
+		downloader->pos = 0;
+	downloader->pos += meta->offset;
+
 	/* Ensure that we have enough buffer space for this data */
+	len = iob_len ( iobuf );
 	max = ( downloader->pos + len );
 	if ( ( rc = downloader_ensure_size ( downloader, max ) ) != 0 )
-		return rc;
+		goto done;
 
 	/* Copy data to buffer */
-	copy_to_user ( downloader->image->data, downloader->pos, data, len );
+	copy_to_user ( downloader->image->data, downloader->pos,
+		       iobuf->data, len );
 
 	/* Update current buffer position */
 	downloader->pos += len;
 
-	return 0;
+ done:
+	free_iob ( iobuf );
+	return rc;
 }
 
 /**
@@ -227,10 +206,10 @@ static void downloader_xfer_close ( struct xfer_interface *xfer, int rc ) {
 static struct xfer_interface_operations downloader_xfer_operations = {
 	.close		= downloader_xfer_close,
 	.vredirect	= xfer_vopen,
-	.seek		= downloader_xfer_seek,
 	.window		= unlimited_xfer_window,
-	.deliver_iob	= xfer_deliver_as_raw,
-	.deliver_raw	= downloader_xfer_deliver_raw,
+	.alloc_iob	= default_xfer_alloc_iob,
+	.deliver_iob	= downloader_xfer_deliver_iob,
+	.deliver_raw	= xfer_deliver_as_iob,
 };
 
 /****************************************************************************
diff --git a/src/core/filter.c b/src/core/filter.c
index 51ec5c4..f9ebe7c 100644
--- a/src/core/filter.c
+++ b/src/core/filter.c
@@ -44,12 +44,6 @@ int filter_vredirect ( struct xfer_interface *xfer, int type,
 	return xfer_vredirect ( other, type, args );
 }
 
-int filter_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
-	struct xfer_interface *other = filter_other_half ( xfer );
-
-	return xfer_seek ( other, offset, whence );
-}
-
 size_t filter_window ( struct xfer_interface *xfer ) {
 	struct xfer_interface *other = filter_other_half ( xfer );
 
diff --git a/src/core/hw.c b/src/core/hw.c
index 3502dbf..65604ee 100644
--- a/src/core/hw.c
+++ b/src/core/hw.c
@@ -36,8 +36,8 @@ static void hw_xfer_close ( struct xfer_interface *xfer, int rc ) {
 static struct xfer_interface_operations hw_xfer_operations = {
 	.close		= hw_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
+	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
 	.deliver_raw	= ignore_xfer_deliver_raw,
 };
diff --git a/src/core/posix_io.c b/src/core/posix_io.c
index 27c7210..2e3781a 100644
--- a/src/core/posix_io.c
+++ b/src/core/posix_io.c
@@ -104,38 +104,11 @@ static void posix_file_xfer_close ( struct xfer_interface *xfer, int rc ) {
 }
 
 /**
- * Handle seek() event
- *
- * @v xfer		POSIX file data transfer interface
- * @v pos		New position
- * @ret rc		Return status code
- */
-static int posix_file_xfer_seek ( struct xfer_interface *xfer, off_t offset,
-				  int whence ) {
-	struct posix_file *file =
-		container_of ( xfer, struct posix_file, xfer );
-
-	switch ( whence ) {
-	case SEEK_SET:
-		file->pos = offset;
-		break;
-	case SEEK_CUR:
-		file->pos += offset;
-		break;
-	}
-
-	if ( file->filesize < file->pos )
-		file->filesize = file->pos;
-
-	return 0;
-}
-
-/**
  * Handle deliver_iob() event
  *
  * @v xfer		POSIX file data transfer interface
  * @v iobuf		I/O buffer
- * @v meta		Data transfer metadata, or NULL
+ * @v meta		Data transfer metadata
  * @ret rc		Return status code
  */
 static int
@@ -145,6 +118,13 @@ posix_file_xfer_deliver_iob ( struct xfer_interface *xfer,
 	struct posix_file *file =
 		container_of ( xfer, struct posix_file, xfer );
 
+	/* Keep track of file position solely for the filesize */
+	if ( meta->whence != SEEK_CUR )
+		file->pos = 0;
+	file->pos += meta->offset;
+	if ( file->filesize < file->pos )
+		file->filesize = file->pos;
+
 	list_add_tail ( &iobuf->list, &file->data );
 	return 0;
 }
@@ -153,7 +133,6 @@ posix_file_xfer_deliver_iob ( struct xfer_interface *xfer,
 static struct xfer_interface_operations posix_file_xfer_operations = {
 	.close		= posix_file_xfer_close,
 	.vredirect	= xfer_vopen,
-	.seek		= posix_file_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= posix_file_xfer_deliver_iob,
diff --git a/src/core/resolv.c b/src/core/resolv.c
index 808ab65..f4a587f 100644
--- a/src/core/resolv.c
+++ b/src/core/resolv.c
@@ -312,7 +312,6 @@ struct named_socket {
 static struct xfer_interface_operations named_xfer_ops = {
 	.close		= ignore_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= no_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
diff --git a/src/core/xfer.c b/src/core/xfer.c
index 3add057..e850347 100644
--- a/src/core/xfer.c
+++ b/src/core/xfer.c
@@ -86,31 +86,6 @@ int xfer_redirect ( struct xfer_interface *xfer, int type, ... ) {
 }
 
 /**
- * Seek to position
- *
- * @v xfer		Data transfer interface
- * @v offset		Offset to new position
- * @v whence		Basis for new position
- * @ret rc		Return status code
- */
-int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
-	struct xfer_interface *dest = xfer_get_dest ( xfer );
-	int rc;
-
-	DBGC ( xfer, "XFER %p->%p seek %s+%ld\n", xfer, dest,
-	       whence_text ( whence ), offset );
-
-	rc = dest->op->seek ( dest, offset, whence );
-
-	if ( rc != 0 ) {
-		DBGC ( xfer, "XFER %p<-%p seek: %s\n", xfer, dest,
-		       strerror ( rc ) );
-	}
-	xfer_put ( dest );
-	return rc;
-}
-
-/**
  * Check flow control window
  *
  * @v xfer		Data transfer interface
@@ -153,7 +128,7 @@ struct io_buffer * xfer_alloc_iob ( struct xfer_interface *xfer, size_t len ) {
  *
  * @v xfer		Data transfer interface
  * @v iobuf		Datagram I/O buffer
- * @v meta		Data transfer metadata, or NULL
+ * @v meta		Data transfer metadata
  * @ret rc		Return status code
  */
 int xfer_deliver_iob_meta ( struct xfer_interface *xfer,
@@ -184,7 +159,8 @@ int xfer_deliver_iob_meta ( struct xfer_interface *xfer,
  */
 int xfer_deliver_iob ( struct xfer_interface *xfer,
 		       struct io_buffer *iobuf ) {
-	return xfer_deliver_iob_meta ( xfer, iobuf, NULL );
+	static struct xfer_metadata dummy_metadata;
+	return xfer_deliver_iob_meta ( xfer, iobuf, &dummy_metadata );
 }
 
 /**
@@ -253,6 +229,31 @@ int xfer_printf ( struct xfer_interface *xfer, const char *format, ... ) {
 	return rc;
 }
 
+/**
+ * Seek to position
+ *
+ * @v xfer		Data transfer interface
+ * @v offset		Offset to new position
+ * @v whence		Basis for new position
+ * @ret rc		Return status code
+ */
+int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
+	struct io_buffer *iobuf;
+	struct xfer_metadata meta = {
+		.offset = offset,
+		.whence = whence,
+	};
+
+	DBGC ( xfer, "XFER %p seek %s+%ld\n", xfer,
+	       whence_text ( whence ), offset );
+
+	/* Allocate and send a zero-length data buffer */
+	iobuf = xfer_alloc_iob ( xfer, 0 );
+	if ( ! iobuf )
+		return -ENOMEM;
+	return xfer_deliver_iob_meta ( xfer, iobuf, &meta );
+}
+
 /****************************************************************************
  *
  * Helper methods
@@ -287,19 +288,6 @@ int ignore_xfer_vredirect ( struct xfer_interface *xfer __unused,
 }
 
 /**
- * Ignore seek() event
- *
- * @v xfer		Data transfer interface
- * @v offset		Offset to new position
- * @v whence		Basis for new position
- * @ret rc		Return status code
- */
-int ignore_xfer_seek ( struct xfer_interface *xfer __unused,
-		       off_t offset __unused, int whence __unused ) {
-	return 0;
-}
-
-/**
  * Unlimited flow control window
  *
  * @v xfer		Data transfer interface
@@ -401,7 +389,6 @@ int ignore_xfer_deliver_raw ( struct xfer_interface *xfer,
 struct xfer_interface_operations null_xfer_ops = {
 	.close		= ignore_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
diff --git a/src/include/gpxe/filter.h b/src/include/gpxe/filter.h
index 3943a9e..126f634 100644
--- a/src/include/gpxe/filter.h
+++ b/src/include/gpxe/filter.h
@@ -41,8 +41,6 @@ filter_other_half ( struct xfer_interface *xfer ) {
 extern void filter_close ( struct xfer_interface *xfer, int rc );
 extern int filter_vredirect ( struct xfer_interface *xfer, int type,
 			      va_list args );
-extern int filter_seek ( struct xfer_interface *xfer, off_t offset,
-			 int whence );
 extern size_t filter_window ( struct xfer_interface *xfer );
 extern struct io_buffer * filter_alloc_iob ( struct xfer_interface *xfer,
 					     size_t len );
diff --git a/src/include/gpxe/xfer.h b/src/include/gpxe/xfer.h
index 68c1169..c75fa00 100644
--- a/src/include/gpxe/xfer.h
+++ b/src/include/gpxe/xfer.h
@@ -32,17 +32,6 @@ struct xfer_interface_operations {
 	 */
 	int ( * vredirect ) ( struct xfer_interface *xfer, int type,
 			      va_list args );
-	/** Seek to position
-	 *
-	 * @v xfer		Data transfer interface
-	 * @v offset		Offset to new position
-	 * @v whence		Basis for new position
-	 * @ret rc		Return status code
-	 *
-	 * @c whence must be one of @c SEEK_SET or @c SEEK_CUR.
-	 */
-	int ( * seek ) ( struct xfer_interface *xfer, off_t offset,
-			 int whence );
 	/** Check flow control window
 	 *
 	 * @v xfer		Data transfer interface
@@ -71,7 +60,7 @@ struct xfer_interface_operations {
 	 *
 	 * @v xfer		Data transfer interface
 	 * @v iobuf		Datagram I/O buffer
-	 * @v meta		Data transfer metadata, or NULL
+	 * @v meta		Data transfer metadata
 	 * @ret rc		Return status code
 	 *
 	 * A data transfer interface that wishes to support only raw
@@ -104,8 +93,21 @@ struct xfer_interface {
 	struct xfer_interface_operations *op;
 };
 
+/** Basis positions for seek() events */
+enum seek_whence {
+	SEEK_CUR = 0,
+	SEEK_SET,
+};
+
 /** Data transfer metadata */
 struct xfer_metadata {
+	/** Position of data within stream */
+	off_t offset;
+	/** Basis for data position
+	 *
+	 * Must be one of @c SEEK_CUR or @c SEEK_SET.
+	 */
+	int whence;
 	/** Source socket address, or NULL */
 	struct sockaddr *src;
 	/** Destination socket address, or NULL */
@@ -114,12 +116,6 @@ struct xfer_metadata {
 	struct net_device *netdev;
 };
 
-/** Basis positions for seek() events */
-enum seek_whence {
-	SEEK_SET = 0,
-	SEEK_CUR,
-};
-
 /**
  * Describe seek basis
  *
@@ -128,8 +124,8 @@ enum seek_whence {
 static inline __attribute__ (( always_inline )) const char *
 whence_text ( int whence ) {
 	switch ( whence ) {
-	case SEEK_SET:	return "SET";
 	case SEEK_CUR:	return "CUR";
+	case SEEK_SET:	return "SET";
 	default:	return "INVALID";
 	}
 }
@@ -141,7 +137,6 @@ extern void xfer_close ( struct xfer_interface *xfer, int rc );
 extern int xfer_vredirect ( struct xfer_interface *xfer, int type,
 			    va_list args );
 extern int xfer_redirect ( struct xfer_interface *xfer, int type, ... );
-extern int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence );
 extern size_t xfer_window ( struct xfer_interface *xfer );
 extern struct io_buffer * xfer_alloc_iob ( struct xfer_interface *xfer,
 					   size_t len );
@@ -156,12 +151,11 @@ extern int xfer_vprintf ( struct xfer_interface *xfer,
 			  const char *format, va_list args );
 extern int xfer_printf ( struct xfer_interface *xfer,
 			 const char *format, ... );
+extern int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence );
 
 extern void ignore_xfer_close ( struct xfer_interface *xfer, int rc );
 extern int ignore_xfer_vredirect ( struct xfer_interface *xfer,
 				   int type, va_list args );
-extern int ignore_xfer_seek ( struct xfer_interface *xfer, off_t offset,
-			      int whence );
 extern size_t unlimited_xfer_window ( struct xfer_interface *xfer );
 extern size_t no_xfer_window ( struct xfer_interface *xfer );
 extern struct io_buffer * default_xfer_alloc_iob ( struct xfer_interface *xfer,
diff --git a/src/interface/pxe/pxe_udp.c b/src/interface/pxe/pxe_udp.c
index 745366f..0d6d1b7 100644
--- a/src/interface/pxe/pxe_udp.c
+++ b/src/interface/pxe/pxe_udp.c
@@ -103,7 +103,6 @@ static int pxe_udp_deliver_iob ( struct xfer_interface *xfer,
 static struct xfer_interface_operations pxe_udp_xfer_operations = {
 	.close		= ignore_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= pxe_udp_deliver_iob,
diff --git a/src/net/tcp.c b/src/net/tcp.c
index 2b9a97b..d6b44b0 100644
--- a/src/net/tcp.c
+++ b/src/net/tcp.c
@@ -1022,7 +1022,6 @@ static int tcp_xfer_deliver_iob ( struct xfer_interface *xfer,
 static struct xfer_interface_operations tcp_xfer_operations = {
 	.close		= tcp_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= tcp_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= tcp_xfer_deliver_iob,
diff --git a/src/net/tcp/ftp.c b/src/net/tcp/ftp.c
index 0e4d969..ffb2fbf 100644
--- a/src/net/tcp/ftp.c
+++ b/src/net/tcp/ftp.c
@@ -299,7 +299,6 @@ static int ftp_control_deliver_raw ( struct xfer_interface *control,
 static struct xfer_interface_operations ftp_control_operations = {
 	.close		= ftp_control_close,
 	.vredirect	= xfer_vopen,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
@@ -364,7 +363,6 @@ static int ftp_data_deliver_iob ( struct xfer_interface *data,
 static struct xfer_interface_operations ftp_data_operations = {
 	.close		= ftp_data_closed,
 	.vredirect	= xfer_vopen,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= ftp_data_deliver_iob,
@@ -397,7 +395,6 @@ static void ftp_xfer_closed ( struct xfer_interface *xfer, int rc ) {
 static struct xfer_interface_operations ftp_xfer_operations = {
 	.close		= ftp_xfer_closed,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
diff --git a/src/net/tcp/http.c b/src/net/tcp/http.c
index 2a5450e..db92e9e 100644
--- a/src/net/tcp/http.c
+++ b/src/net/tcp/http.c
@@ -426,7 +426,6 @@ static void http_socket_close ( struct xfer_interface *socket, int rc ) {
 static struct xfer_interface_operations http_socket_operations = {
 	.close		= http_socket_close,
 	.vredirect	= xfer_vopen,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= http_socket_deliver_iob,
@@ -453,7 +452,6 @@ static void http_xfer_close ( struct xfer_interface *xfer, int rc ) {
 static struct xfer_interface_operations http_xfer_operations = {
 	.close		= http_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
diff --git a/src/net/tcp/iscsi.c b/src/net/tcp/iscsi.c
index 86f3c67..ff1478e 100644
--- a/src/net/tcp/iscsi.c
+++ b/src/net/tcp/iscsi.c
@@ -1322,7 +1322,6 @@ static int iscsi_vredirect ( struct xfer_interface *socket, int type,
 static struct xfer_interface_operations iscsi_socket_operations = {
 	.close		= iscsi_socket_close,
 	.vredirect	= iscsi_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
diff --git a/src/net/tls.c b/src/net/tls.c
index f67bdd4..834686f 100644
--- a/src/net/tls.c
+++ b/src/net/tls.c
@@ -1460,7 +1460,6 @@ static int tls_plainstream_deliver_raw ( struct xfer_interface *xfer,
 static struct xfer_interface_operations tls_plainstream_operations = {
 	.close		= tls_plainstream_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= filter_seek,
 	.window		= tls_plainstream_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
@@ -1600,7 +1599,6 @@ static int tls_cipherstream_deliver_raw ( struct xfer_interface *xfer,
 static struct xfer_interface_operations tls_cipherstream_operations = {
 	.close		= tls_cipherstream_close,
 	.vredirect	= xfer_vopen,
-	.seek		= filter_seek,
 	.window		= filter_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
diff --git a/src/net/udp.c b/src/net/udp.c
index eb24149..89a5b86 100644
--- a/src/net/udp.c
+++ b/src/net/udp.c
@@ -415,7 +415,6 @@ static int udp_xfer_deliver_iob ( struct xfer_interface *xfer,
 static struct xfer_interface_operations udp_xfer_operations = {
 	.close		= udp_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= udp_alloc_iob,
 	.deliver_iob	= udp_xfer_deliver_iob,
diff --git a/src/net/udp/dhcp.c b/src/net/udp/dhcp.c
index b10c3ee..2521f9a 100644
--- a/src/net/udp/dhcp.c
+++ b/src/net/udp/dhcp.c
@@ -927,8 +927,8 @@ static int dhcp_deliver_raw ( struct xfer_interface *xfer,
 static struct xfer_interface_operations dhcp_xfer_operations = {
 	.close		= ignore_xfer_close,
 	.vredirect	= xfer_vopen,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
+	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
 	.deliver_raw	= dhcp_deliver_raw,
 };
diff --git a/src/net/udp/dns.c b/src/net/udp/dns.c
index f32b2e0..d82d124 100644
--- a/src/net/udp/dns.c
+++ b/src/net/udp/dns.c
@@ -435,7 +435,6 @@ static void dns_xfer_close ( struct xfer_interface *socket, int rc ) {
 static struct xfer_interface_operations dns_socket_operations = {
 	.close		= dns_xfer_close,
 	.vredirect	= xfer_vopen,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
diff --git a/src/net/udp/tftp.c b/src/net/udp/tftp.c
index d8719ac..4d44190 100644
--- a/src/net/udp/tftp.c
+++ b/src/net/udp/tftp.c
@@ -554,6 +554,7 @@ static int tftp_rx_oack ( struct tftp_request *tftp, void *buf, size_t len ) {
 static int tftp_rx_data ( struct tftp_request *tftp,
 			  struct io_buffer *iobuf ) {
 	struct tftp_data *data = iobuf->data;
+	struct xfer_metadata meta;
 	int block;
 	off_t offset;
 	size_t data_len;
@@ -580,8 +581,10 @@ static int tftp_rx_data ( struct tftp_request *tftp,
 	}
 
 	/* Deliver data */
-	xfer_seek ( &tftp->xfer, offset, SEEK_SET );
-	rc = xfer_deliver_iob ( &tftp->xfer, iobuf );
+	memset ( &meta, 0, sizeof ( meta ) );
+	meta.whence = SEEK_SET;
+	meta.offset = offset;
+	rc = xfer_deliver_iob_meta ( &tftp->xfer, iobuf, &meta );
 	iobuf = NULL;
 	if ( rc != 0 ) {
 		DBGC ( tftp, "TFTP %p could not deliver data: %s\n",
@@ -763,7 +766,6 @@ static void tftp_socket_close ( struct xfer_interface *socket, int rc ) {
 static struct xfer_interface_operations tftp_socket_operations = {
 	.close		= tftp_socket_close,
 	.vredirect	= xfer_vopen,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= tftp_socket_deliver_iob,
@@ -811,7 +813,6 @@ static void tftp_mc_socket_close ( struct xfer_interface *mc_socket,
 static struct xfer_interface_operations tftp_mc_socket_operations = {
 	.close		= tftp_mc_socket_close,
 	.vredirect	= xfer_vopen,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= tftp_mc_socket_deliver_iob,
@@ -838,7 +839,6 @@ static void tftp_xfer_close ( struct xfer_interface *xfer, int rc ) {
 static struct xfer_interface_operations tftp_xfer_operations = {
 	.close		= tftp_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,