[interface] Convert all data-xfer interfaces to generic interfaces

Remove data-xfer as an interface type, and replace data-xfer
interfaces with generic interfaces supporting the data-xfer methods.

Filter interfaces (as used by the TLS layer) are handled using the
generic pass-through interface capability.  A side-effect of this is
that deliver_raw() no longer exists as a data-xfer method.  (In
practice this doesn't lose any efficiency, since there are no
instances within the current codebase where xfer_deliver_raw() is used
to pass data to an interface supporting the deliver_raw() method.)

Signed-off-by: Michael Brown <mcb30@ipxe.org>

4 files changed, 146 insertions, 240 deletions

diff --git a/src/net/udp/dhcp.c b/src/net/udp/dhcp.c
index 991983197..fb62bef53 100644
--- a/src/net/udp/dhcp.c
+++ b/src/net/udp/dhcp.c
@@ -26,6 +26,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <assert.h>
 #include <byteswap.h>
 #include <ipxe/if_ether.h>
+#include <ipxe/iobuf.h>
 #include <ipxe/netdevice.h>
 #include <ipxe/device.h>
 #include <ipxe/xfer.h>
@@ -240,7 +241,7 @@ struct dhcp_session {
 	/** Job control interface */
 	struct interface job;
 	/** Data transfer interface */
-	struct xfer_interface xfer;
+	struct interface xfer;
 
 	/** Network device being configured */
 	struct net_device *netdev;
@@ -298,8 +299,7 @@ static void dhcp_finished ( struct dhcp_session *dhcp, int rc ) {
 	stop_timer ( &dhcp->timer );
 
 	/* Shut down interfaces */
-	xfer_nullify ( &dhcp->xfer );
-	xfer_close ( &dhcp->xfer, rc );
+	intf_shutdown ( &dhcp->xfer, rc );
 	intf_shutdown ( &dhcp->job, rc );
 }
 
@@ -1241,8 +1241,8 @@ static int dhcp_tx ( struct dhcp_session *dhcp ) {
 
 	/* Transmit the packet */
 	iob_put ( iobuf, dhcppkt.len );
-	if ( ( rc = xfer_deliver_iob_meta ( &dhcp->xfer, iob_disown ( iobuf ),
-					    &meta ) ) != 0 ) {
+	if ( ( rc = xfer_deliver ( &dhcp->xfer, iob_disown ( iobuf ),
+				   &meta ) ) != 0 ) {
 		DBGC ( dhcp, "DHCP %p could not transmit UDP packet: %s\n",
 		       dhcp, strerror ( rc ) );
 		goto done;
@@ -1256,16 +1256,14 @@ static int dhcp_tx ( struct dhcp_session *dhcp ) {
 /**
  * Receive new data
  *
- * @v xfer 		Data transfer interface
+ * @v dhcp		DHCP session
  * @v iobuf		I/O buffer
  * @v meta		Transfer metadata
  * @ret rc		Return status code
  */
-static int dhcp_deliver_iob ( struct xfer_interface *xfer,
-			      struct io_buffer *iobuf,
-			      struct xfer_metadata *meta ) {
-	struct dhcp_session *dhcp =
-		container_of ( xfer, struct dhcp_session, xfer );
+static int dhcp_deliver ( struct dhcp_session *dhcp,
+			  struct io_buffer *iobuf,
+			  struct xfer_metadata *meta ) {
 	struct sockaddr_in *peer;
 	size_t data_len;
 	struct dhcp_packet *dhcppkt;
@@ -1328,15 +1326,14 @@ static int dhcp_deliver_iob ( struct xfer_interface *xfer,
 }
 
 /** DHCP data transfer interface operations */
-static struct xfer_interface_operations dhcp_xfer_operations = {
-	.close		= ignore_xfer_close,
-	.vredirect	= xfer_vreopen,
-	.window		= unlimited_xfer_window,
-	.alloc_iob	= default_xfer_alloc_iob,
-	.deliver_iob	= dhcp_deliver_iob,
-	.deliver_raw	= xfer_deliver_as_iob,
+static struct interface_operation dhcp_xfer_operations[] = {
+	INTF_OP ( xfer_deliver, struct dhcp_session *, dhcp_deliver ),
 };
 
+/** DHCP data transfer interface descriptor */
+static struct interface_descriptor dhcp_xfer_desc =
+	INTF_DESC ( struct dhcp_session, xfer, dhcp_xfer_operations );
+
 /**
  * Handle DHCP retry timer expiry
  *
@@ -1427,7 +1424,7 @@ int start_dhcp ( struct interface *job, struct net_device *netdev ) {
 		return -ENOMEM;
 	ref_init ( &dhcp->refcnt, dhcp_free );
 	intf_init ( &dhcp->job, &dhcp_job_desc, &dhcp->refcnt );
-	xfer_init ( &dhcp->xfer, &dhcp_xfer_operations, &dhcp->refcnt );
+	intf_init ( &dhcp->xfer, &dhcp_xfer_desc, &dhcp->refcnt );
 	timer_init ( &dhcp->timer, dhcp_timer_expired );
 	dhcp->netdev = netdev_get ( netdev );
 	dhcp->local.sin_family = AF_INET;
@@ -1530,7 +1527,7 @@ int start_pxebs ( struct interface *job, struct net_device *netdev,
 		return -ENOMEM;
 	ref_init ( &dhcp->refcnt, dhcp_free );
 	intf_init ( &dhcp->job, &dhcp_job_desc, &dhcp->refcnt );
-	xfer_init ( &dhcp->xfer, &dhcp_xfer_operations, &dhcp->refcnt );
+	intf_init ( &dhcp->xfer, &dhcp_xfer_desc, &dhcp->refcnt );
 	timer_init ( &dhcp->timer, dhcp_timer_expired );
 	dhcp->netdev = netdev_get ( netdev );
 	dhcp->local.sin_family = AF_INET;
diff --git a/src/net/udp/dns.c b/src/net/udp/dns.c
index fd1ea0a28..8283e6fba 100644
--- a/src/net/udp/dns.c
+++ b/src/net/udp/dns.c
@@ -28,6 +28,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <errno.h>
 #include <byteswap.h>
 #include <ipxe/refcnt.h>
+#include <ipxe/iobuf.h>
 #include <ipxe/xfer.h>
 #include <ipxe/open.h>
 #include <ipxe/resolv.h>
@@ -60,7 +61,7 @@ struct dns_request {
 	/** Name resolution interface */
 	struct interface resolv;
 	/** Data transfer interface */
-	struct xfer_interface socket;
+	struct interface socket;
 	/** Retry timer */
 	struct retry_timer timer;
 
@@ -89,11 +90,8 @@ static void dns_done ( struct dns_request *dns, int rc ) {
 	/* Stop the retry timer */
 	stop_timer ( &dns->timer );
 
-	/* Close data transfer interface */
-	xfer_nullify ( &dns->socket );
-	xfer_close ( &dns->socket, rc );
-
 	/* Shut down interfaces */
+	intf_shutdown ( &dns->socket, rc );
 	intf_shutdown ( &dns->resolv, rc );
 }
 
@@ -322,25 +320,26 @@ static void dns_timer_expired ( struct retry_timer *timer, int fail ) {
 /**
  * Receive new data
  *
- * @v socket		UDP socket
- * @v data		DNS reply
- * @v len		Length of DNS reply
+ * @v dns		DNS request
+ * @v iobuf		I/O buffer
+ * @v meta		Data transfer metadata
  * @ret rc		Return status code
  */
-static int dns_xfer_deliver_raw ( struct xfer_interface *socket,
-				  const void *data, size_t len ) {
-	struct dns_request *dns =
-		container_of ( socket, struct dns_request, socket );
-	const struct dns_header *reply = data;
+static int dns_xfer_deliver ( struct dns_request *dns,
+			      struct io_buffer *iobuf,
+			      struct xfer_metadata *meta __unused ) {
+	const struct dns_header *reply = iobuf->data;
 	union dns_rr_info *rr_info;
 	struct sockaddr_in *sin;
 	unsigned int qtype = dns->qinfo->qtype;
+	int rc;
 
 	/* Sanity check */
-	if ( len < sizeof ( *reply ) ) {
+	if ( iob_len ( iobuf ) < sizeof ( *reply ) ) {
 		DBGC ( dns, "DNS %p received underlength packet length %zd\n",
-		       dns, len );
-		return -EINVAL;
+		       dns, iob_len ( iobuf ) );
+		rc = -EINVAL;
+		goto done;
 	}
 
 	/* Check reply ID matches query ID */
@@ -348,7 +347,8 @@ static int dns_xfer_deliver_raw ( struct xfer_interface *socket,
 		DBGC ( dns, "DNS %p received unexpected reply ID %d "
 		       "(wanted %d)\n", dns, ntohs ( reply->id ),
 		       ntohs ( dns->query.dns.id ) );
-		return -EINVAL;
+		rc = -EINVAL;
+		goto done;
 	}
 
 	DBGC ( dns, "DNS %p received reply ID %d\n", dns, ntohs ( reply->id ));
@@ -382,7 +382,8 @@ static int dns_xfer_deliver_raw ( struct xfer_interface *socket,
 
 			/* Mark operation as complete */
 			dns_done ( dns, 0 );
-			return 0;
+			rc = 0;
+			goto done;
 
 		case htons ( DNS_TYPE_CNAME ):
 
@@ -399,7 +400,8 @@ static int dns_xfer_deliver_raw ( struct xfer_interface *socket,
 				DBGC ( dns, "DNS %p recursion exceeded\n",
 				       dns );
 				dns_done ( dns, -ELOOP );
-				return 0;
+				rc = 0;
+				goto done;
 			}
 			break;
 
@@ -422,7 +424,8 @@ static int dns_xfer_deliver_raw ( struct xfer_interface *socket,
 		DBGC ( dns, "DNS %p found no A record; trying CNAME\n", dns );
 		dns->qinfo->qtype = htons ( DNS_TYPE_CNAME );
 		dns_send_packet ( dns );
-		return 0;
+		rc = 0;
+		goto done;
 
 	case htons ( DNS_TYPE_CNAME ):
 		/* We asked for a CNAME record.  If we got a response
@@ -431,29 +434,35 @@ static int dns_xfer_deliver_raw ( struct xfer_interface *socket,
 		 */
 		if ( dns->qinfo->qtype == htons ( DNS_TYPE_A ) ) {
 			dns_send_packet ( dns );
-			return 0;
+			rc = 0;
+			goto done;
 		} else {
 			DBGC ( dns, "DNS %p found no CNAME record\n", dns );
 			dns_done ( dns, -ENXIO );
-			return 0;
+			rc = 0;
+			goto done;
 		}
 
 	default:
 		assert ( 0 );
 		dns_done ( dns, -EINVAL );
-		return 0;
+		rc = -EINVAL;
+		goto done;
 	}
+
+ done:
+	/* Free I/O buffer */
+	free_iob ( iobuf );
+	return rc;
 }
 
 /**
  * Receive new data
  *
- * @v socket		UDP socket
+ * @v dns		DNS request
  * @v rc		Reason for close
  */
-static void dns_xfer_close ( struct xfer_interface *socket, int rc ) {
-	struct dns_request *dns =
-		container_of ( socket, struct dns_request, socket );
+static void dns_xfer_close ( struct dns_request *dns, int rc ) {
 
 	if ( ! rc )
 		rc = -ECONNABORTED;
@@ -461,16 +470,16 @@ static void dns_xfer_close ( struct xfer_interface *socket, int rc ) {
 	dns_done ( dns, rc );
 }
 
-/** DNS socket operations */
-static struct xfer_interface_operations dns_socket_operations = {
-	.close		= dns_xfer_close,
-	.vredirect	= xfer_vreopen,
-	.window		= unlimited_xfer_window,
-	.alloc_iob	= default_xfer_alloc_iob,
-	.deliver_iob	= xfer_deliver_as_raw,
-	.deliver_raw	= dns_xfer_deliver_raw,
+/** DNS socket interface operations */
+static struct interface_operation dns_socket_operations[] = {
+	INTF_OP ( xfer_deliver, struct dns_request *, dns_xfer_deliver ),
+	INTF_OP ( intf_close, struct dns_request *, dns_xfer_close ),
 };
 
+/** DNS socket interface descriptor */
+static struct interface_descriptor dns_socket_desc =
+	INTF_DESC ( struct dns_request, socket, dns_socket_operations );
+
 /** DNS resolver interface operations */
 static struct interface_operation dns_resolv_op[] = {
 	INTF_OP ( intf_close, struct dns_request *, dns_done ),
@@ -517,7 +526,7 @@ static int dns_resolv ( struct interface *resolv,
 	}
 	ref_init ( &dns->refcnt, NULL );
 	intf_init ( &dns->resolv, &dns_resolv_desc, &dns->refcnt );
-	xfer_init ( &dns->socket, &dns_socket_operations, &dns->refcnt );
+	intf_init ( &dns->socket, &dns_socket_desc, &dns->refcnt );
 	timer_init ( &dns->timer, dns_timer_expired );
 	memcpy ( &dns->sa, sa, sizeof ( dns->sa ) );
 
diff --git a/src/net/udp/slam.c b/src/net/udp/slam.c
index a5a2421fa..84bb9cba3 100644
--- a/src/net/udp/slam.c
+++ b/src/net/udp/slam.c
@@ -119,11 +119,11 @@ struct slam_request {
 	struct refcnt refcnt;
 
 	/** Data transfer interface */
-	struct xfer_interface xfer;
+	struct interface xfer;
 	/** Unicast socket */
-	struct xfer_interface socket;
+	struct interface socket;
 	/** Multicast socket */
-	struct xfer_interface mc_socket;
+	struct interface mc_socket;
 
 	/** Master client retry timer */
 	struct retry_timer master_timer;
@@ -184,12 +184,9 @@ static void slam_finished ( struct slam_request *slam, int rc ) {
 	stop_timer ( &slam->slave_timer );
 
 	/* Close all data transfer interfaces */
-	xfer_nullify ( &slam->socket );
-	xfer_close ( &slam->socket, rc );
-	xfer_nullify ( &slam->mc_socket );
-	xfer_close ( &slam->mc_socket, rc );
-	xfer_nullify ( &slam->xfer );
-	xfer_close ( &slam->xfer, rc );
+	intf_shutdown ( &slam->socket, rc );
+	intf_shutdown ( &slam->mc_socket, rc );
+	intf_shutdown ( &slam->xfer, rc );
 }
 
 /****************************************************************************
@@ -473,15 +470,13 @@ static int slam_pull_header ( struct slam_request *slam,
 /**
  * Receive SLAM data packet
  *
- * @v mc_socket		SLAM multicast socket
+ * @v slam		SLAM request
  * @v iobuf		I/O buffer
  * @ret rc		Return status code
  */
-static int slam_mc_socket_deliver ( struct xfer_interface *mc_socket,
+static int slam_mc_socket_deliver ( struct slam_request *slam,
 				    struct io_buffer *iobuf,
 				    struct xfer_metadata *rx_meta __unused ) {
-	struct slam_request *slam =
-		container_of ( mc_socket, struct slam_request, mc_socket );
 	struct xfer_metadata meta;
 	unsigned long packet;
 	size_t len;
@@ -533,8 +528,7 @@ static int slam_mc_socket_deliver ( struct xfer_interface *mc_socket,
 	memset ( &meta, 0, sizeof ( meta ) );
 	meta.whence = SEEK_SET;
 	meta.offset = ( packet * slam->block_size );
-	if ( ( rc = xfer_deliver_iob_meta ( &slam->xfer, iobuf,
-					    &meta ) ) != 0 )
+	if ( ( rc = xfer_deliver ( &slam->xfer, iobuf, &meta ) ) != 0 )
 		goto err;
 
 	/* Mark block as received */
@@ -556,15 +550,13 @@ static int slam_mc_socket_deliver ( struct xfer_interface *mc_socket,
 /**
  * Receive SLAM non-data packet
  *
- * @v socket		SLAM unicast socket
+ * @v slam		SLAM request
  * @v iobuf		I/O buffer
  * @ret rc		Return status code
  */
-static int slam_socket_deliver ( struct xfer_interface *socket,
+static int slam_socket_deliver ( struct slam_request *slam,
 				 struct io_buffer *iobuf,
 				 struct xfer_metadata *rx_meta __unused ) {
-	struct slam_request *slam =
-		container_of ( socket, struct slam_request, socket );
 	int rc;
 
 	/* Restart the master client timer */
@@ -597,90 +589,41 @@ static int slam_socket_deliver ( struct xfer_interface *socket,
 
 }
 
-/**
- * Close SLAM unicast socket
- *
- * @v socket		SLAM unicast socket
- * @v rc		Reason for close
- */
-static void slam_socket_close ( struct xfer_interface *socket, int rc ) {
-	struct slam_request *slam =
-		container_of ( socket, struct slam_request, socket );
-
-	DBGC ( slam, "SLAM %p unicast socket closed: %s\n",
-	       slam, strerror ( rc ) );
-
-	slam_finished ( slam, rc );
-}
-
-/** SLAM unicast socket data transfer operations */
-static struct xfer_interface_operations slam_socket_operations = {
-	.close		= slam_socket_close,
-	.vredirect	= xfer_vreopen,
-	.window		= unlimited_xfer_window,
-	.alloc_iob	= default_xfer_alloc_iob,
-	.deliver_iob	= slam_socket_deliver,
-	.deliver_raw	= xfer_deliver_as_iob,
+/** SLAM unicast socket interface operations */
+static struct interface_operation slam_socket_operations[] = {
+	INTF_OP ( xfer_deliver, struct slam_request *, slam_socket_deliver ),
+	INTF_OP ( intf_close, struct slam_request *, slam_finished ),
 };
 
-/**
- * Close SLAM multicast socket
- *
- * @v mc_socket		SLAM multicast socket
- * @v rc		Reason for close
- */
-static void slam_mc_socket_close ( struct xfer_interface *mc_socket, int rc ){
-	struct slam_request *slam =
-		container_of ( mc_socket, struct slam_request, mc_socket );
-
-	DBGC ( slam, "SLAM %p multicast socket closed: %s\n",
-	       slam, strerror ( rc ) );
-
-	slam_finished ( slam, rc );
-}
+/** SLAM unicast socket interface descriptor */
+static struct interface_descriptor slam_socket_desc =
+	INTF_DESC ( struct slam_request, socket, slam_socket_operations );
 
-/** SLAM multicast socket data transfer operations */
-static struct xfer_interface_operations slam_mc_socket_operations = {
-	.close		= slam_mc_socket_close,
-	.vredirect	= xfer_vreopen,
-	.window		= unlimited_xfer_window,
-	.alloc_iob	= default_xfer_alloc_iob,
-	.deliver_iob	= slam_mc_socket_deliver,
-	.deliver_raw	= xfer_deliver_as_iob,
+/** SLAM multicast socket interface operations */
+static struct interface_operation slam_mc_socket_operations[] = {
+	INTF_OP ( xfer_deliver, struct slam_request *, slam_mc_socket_deliver ),
+	INTF_OP ( intf_close, struct slam_request *, slam_finished ),
 };
 
+/** SLAM multicast socket interface descriptor */
+static struct interface_descriptor slam_mc_socket_desc =
+	INTF_DESC ( struct slam_request, mc_socket, slam_mc_socket_operations );
+
 /****************************************************************************
  *
  * Data transfer interface
  *
  */
 
-/**
- * Close SLAM data transfer interface
- *
- * @v xfer		SLAM data transfer interface
- * @v rc		Reason for close
- */
-static void slam_xfer_close ( struct xfer_interface *xfer, int rc ) {
-	struct slam_request *slam =
-		container_of ( xfer, struct slam_request, xfer );
-
-	DBGC ( slam, "SLAM %p data transfer interface closed: %s\n",
-	       slam, strerror ( rc ) );
-
-	slam_finished ( slam, rc );
-}
-
-/** SLAM data transfer operations */
-static struct xfer_interface_operations slam_xfer_operations = {
-	.close		= slam_xfer_close,
-	.vredirect	= ignore_xfer_vredirect,
-	.window		= unlimited_xfer_window,
-	.alloc_iob	= default_xfer_alloc_iob,
-	.deliver_iob	= xfer_deliver_as_raw,
-	.deliver_raw	= ignore_xfer_deliver_raw,
+/** SLAM data transfer interface operations */
+static struct interface_operation slam_xfer_operations[] = {
+	INTF_OP ( intf_close, struct slam_request *, slam_finished ),
 };
 
+/** SLAM data transfer interface descriptor */
+static struct interface_descriptor slam_xfer_desc =
+	INTF_DESC ( struct slam_request, xfer, slam_xfer_operations );
+
 /**
  * Parse SLAM URI multicast address
  *
@@ -729,7 +672,7 @@ static int slam_parse_multicast_address ( struct slam_request *slam,
  * @v uri		Uniform Resource Identifier
  * @ret rc		Return status code
  */
-static int slam_open ( struct xfer_interface *xfer, struct uri *uri ) {
+static int slam_open ( struct interface *xfer, struct uri *uri ) {
 	static const struct sockaddr_in default_multicast = {
 		.sin_family = AF_INET,
 		.sin_port = htons ( SLAM_DEFAULT_MULTICAST_PORT ),
@@ -749,10 +692,9 @@ static int slam_open ( struct xfer_interface *xfer, struct uri *uri ) {
 	if ( ! slam )
 		return -ENOMEM;
 	ref_init ( &slam->refcnt, slam_free );
-	xfer_init ( &slam->xfer, &slam_xfer_operations, &slam->refcnt );
-	xfer_init ( &slam->socket, &slam_socket_operations, &slam->refcnt );
-	xfer_init ( &slam->mc_socket, &slam_mc_socket_operations,
-		    &slam->refcnt );
+	intf_init ( &slam->xfer, &slam_xfer_desc, &slam->refcnt );
+	intf_init ( &slam->socket, &slam_socket_desc, &slam->refcnt );
+	intf_init ( &slam->mc_socket, &slam_mc_socket_desc, &slam->refcnt );
 	timer_init ( &slam->master_timer, slam_master_timer_expired );
 	timer_init ( &slam->slave_timer, slam_slave_timer_expired );
 	/* Fake an invalid cached header of { 0x00, ... } */
@@ -795,7 +737,7 @@ static int slam_open ( struct xfer_interface *xfer, struct uri *uri ) {
 	start_timer_fixed ( &slam->slave_timer, SLAM_SLAVE_TIMEOUT );
 
 	/* Attach to parent interface, mortalise self, and return */
-	xfer_plug_plug ( &slam->xfer, xfer );
+	intf_plug_plug ( &slam->xfer, xfer );
 	ref_put ( &slam->refcnt );
 	return 0;
 
diff --git a/src/net/udp/tftp.c b/src/net/udp/tftp.c
index 5e98f58cd..3bcd0a258 100644
--- a/src/net/udp/tftp.c
+++ b/src/net/udp/tftp.c
@@ -27,6 +27,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <errno.h>
 #include <assert.h>
 #include <ipxe/refcnt.h>
+#include <ipxe/iobuf.h>
 #include <ipxe/xfer.h>
 #include <ipxe/open.h>
 #include <ipxe/uri.h>
@@ -79,14 +80,14 @@ struct tftp_request {
 	/** Reference count */
 	struct refcnt refcnt;
 	/** Data transfer interface */
-	struct xfer_interface xfer;
+	struct interface xfer;
 
 	/** URI being fetched */
 	struct uri *uri;
 	/** Transport layer interface */
-	struct xfer_interface socket;
+	struct interface socket;
 	/** Multicast transport layer interface */
-	struct xfer_interface mc_socket;
+	struct interface mc_socket;
 
 	/** Data block size
 	 *
@@ -183,12 +184,9 @@ static void tftp_done ( struct tftp_request *tftp, int rc ) {
 	stop_timer ( &tftp->timer );
 
 	/* Close all data transfer interfaces */
-	xfer_nullify ( &tftp->socket );
-	xfer_close ( &tftp->socket, rc );
-	xfer_nullify ( &tftp->mc_socket );
-	xfer_close ( &tftp->mc_socket, rc );
-	xfer_nullify ( &tftp->xfer );
-	xfer_close ( &tftp->xfer, rc );
+	intf_shutdown ( &tftp->socket, rc );
+	intf_shutdown ( &tftp->mc_socket, rc );
+	intf_shutdown ( &tftp->xfer, rc );
 }
 
 /**
@@ -202,7 +200,7 @@ static int tftp_reopen ( struct tftp_request *tftp ) {
 	int rc;
 
 	/* Close socket */
-	xfer_close ( &tftp->socket, 0 );
+	intf_restart ( &tftp->socket, 0 );
 
 	/* Disable ACK sending. */
 	tftp->flags &= ~TFTP_FL_SEND_ACK;
@@ -236,7 +234,7 @@ static int tftp_reopen_mc ( struct tftp_request *tftp,
 	int rc;
 
 	/* Close multicast socket */
-	xfer_close ( &tftp->mc_socket, 0 );
+	intf_restart ( &tftp->mc_socket, 0 );
 
 	/* Open multicast socket.  We never send via this socket, so
 	 * use the local address as the peer address (since the peer
@@ -423,7 +421,7 @@ static int tftp_send_ack ( struct tftp_request *tftp ) {
 	ack->block = htons ( block );
 
 	/* ACK always goes to the peer recorded from the RRQ response */
-	return xfer_deliver_iob_meta ( &tftp->socket, iobuf, &meta );
+	return xfer_deliver ( &tftp->socket, iobuf, &meta );
 }
 
 /**
@@ -459,7 +457,7 @@ static int tftp_send_error ( struct tftp_request *tftp, int errcode,
 	strcpy ( err->errmsg, errmsg );
 
 	/* ERR always goes to the peer recorded from the RRQ response */
-	return xfer_deliver_iob_meta ( &tftp->socket, iobuf, &meta );
+	return xfer_deliver ( &tftp->socket, iobuf, &meta );
 }
 
 /**
@@ -525,7 +523,7 @@ static void tftp_timer_expired ( struct retry_timer *timer, int fail ) {
 				tftp->flags = TFTP_FL_RRQ_SIZES;
 
 				/* Close multicast socket */
-				xfer_close ( &tftp->mc_socket, 0 );
+				intf_restart ( &tftp->mc_socket, 0 );
 
 				/* Reset retry timer */
 				start_timer_nodelay ( &tftp->timer );
@@ -858,8 +856,8 @@ static int tftp_rx_data ( struct tftp_request *tftp,
 	memset ( &meta, 0, sizeof ( meta ) );
 	meta.whence = SEEK_SET;
 	meta.offset = offset;
-	if ( ( rc = xfer_deliver_iob_meta ( &tftp->xfer, iob_disown ( iobuf ),
-					    &meta ) ) != 0 ) {
+	if ( ( rc = xfer_deliver ( &tftp->xfer, iob_disown ( iobuf ),
+				   &meta ) ) != 0 ) {
 		DBGC ( tftp, "TFTP %p could not deliver data: %s\n",
 		       tftp, strerror ( rc ) );
 		goto done;
@@ -998,16 +996,14 @@ static int tftp_rx ( struct tftp_request *tftp,
 /**
  * Receive new data via socket
  *
- * @v socket		Transport layer interface
+ * @v tftp		TFTP connection
  * @v iobuf		I/O buffer
  * @v meta		Transfer metadata
  * @ret rc		Return status code
  */
-static int tftp_socket_deliver_iob ( struct xfer_interface *socket,
-				     struct io_buffer *iobuf,
-				     struct xfer_metadata *meta ) {
-	struct tftp_request *tftp =
-		container_of ( socket, struct tftp_request, socket );
+static int tftp_socket_deliver ( struct tftp_request *tftp,
+				 struct io_buffer *iobuf,
+				 struct xfer_metadata *meta ) {
 
 	/* Enable sending ACKs when we receive a unicast packet.  This
 	 * covers three cases:
@@ -1030,67 +1026,30 @@ static int tftp_socket_deliver_iob ( struct xfer_interface *socket,
 }
 
 /** TFTP socket operations */
-static struct xfer_interface_operations tftp_socket_operations = {
-	.close		= ignore_xfer_close,
-	.vredirect	= xfer_vreopen,
-	.window		= unlimited_xfer_window,
-	.alloc_iob	= default_xfer_alloc_iob,
-	.deliver_iob	= tftp_socket_deliver_iob,
-	.deliver_raw	= xfer_deliver_as_iob,
+static struct interface_operation tftp_socket_operations[] = {
+	INTF_OP ( xfer_deliver, struct tftp_request *, tftp_socket_deliver ),
 };
 
-/**
- * Receive new data via multicast socket
- *
- * @v mc_socket		Multicast transport layer interface
- * @v iobuf		I/O buffer
- * @v meta		Transfer metadata
- * @ret rc		Return status code
- */
-static int tftp_mc_socket_deliver_iob ( struct xfer_interface *mc_socket,
-					struct io_buffer *iobuf,
-					struct xfer_metadata *meta ) {
-	struct tftp_request *tftp =
-		container_of ( mc_socket, struct tftp_request, mc_socket );
-
-	return tftp_rx ( tftp, iobuf, meta );
-}
+/** TFTP socket interface descriptor */
+static struct interface_descriptor tftp_socket_desc =
+	INTF_DESC ( struct tftp_request, socket, tftp_socket_operations );
 
 /** TFTP multicast socket operations */
-static struct xfer_interface_operations tftp_mc_socket_operations = {
-	.close		= ignore_xfer_close,
-	.vredirect	= xfer_vreopen,
-	.window		= unlimited_xfer_window,
-	.alloc_iob	= default_xfer_alloc_iob,
-	.deliver_iob	= tftp_mc_socket_deliver_iob,
-	.deliver_raw	= xfer_deliver_as_iob,
+static struct interface_operation tftp_mc_socket_operations[] = {
+	INTF_OP ( xfer_deliver, struct tftp_request *, tftp_rx ),
 };
 
-/**
- * Close TFTP data transfer interface
- *
- * @v xfer		Data transfer interface
- * @v rc		Reason for close
- */
-static void tftp_xfer_close ( struct xfer_interface *xfer, int rc ) {
-	struct tftp_request *tftp =
-		container_of ( xfer, struct tftp_request, xfer );
-
-	DBGC ( tftp, "TFTP %p interface closed: %s\n",
-	       tftp, strerror ( rc ) );
-
-	tftp_done ( tftp, rc );
-}
+/** TFTP multicast socket interface descriptor */
+static struct interface_descriptor tftp_mc_socket_desc =
+	INTF_DESC ( struct tftp_request, mc_socket, tftp_mc_socket_operations );
 
 /**
  * Check flow control window
  *
- * @v xfer		Data transfer interface
+ * @v tftp		TFTP connection
  * @ret len		Length of window
  */
-static size_t tftp_xfer_window ( struct xfer_interface *xfer ) {
-	struct tftp_request *tftp =
-		container_of ( xfer, struct tftp_request, xfer );
+static size_t tftp_xfer_window ( struct tftp_request *tftp ) {
 
 	/* We abuse this data-xfer method to convey the blocksize to
 	 * the caller.  This really should be done using some kind of
@@ -1101,15 +1060,15 @@ static size_t tftp_xfer_window ( struct xfer_interface *xfer ) {
 }
 
 /** TFTP data transfer interface operations */
-static struct xfer_interface_operations tftp_xfer_operations = {
-	.close		= tftp_xfer_close,
-	.vredirect	= ignore_xfer_vredirect,
-	.window		= tftp_xfer_window,
-	.alloc_iob	= default_xfer_alloc_iob,
-	.deliver_iob	= xfer_deliver_as_raw,
-	.deliver_raw	= ignore_xfer_deliver_raw,
+static struct interface_operation tftp_xfer_operations[] = {
+	INTF_OP ( xfer_window, struct tftp_request *, tftp_xfer_window ),
+	INTF_OP ( intf_close, struct tftp_request *, tftp_done ),
 };
 
+/** TFTP data transfer interface descriptor */
+static struct interface_descriptor tftp_xfer_desc =
+	INTF_DESC ( struct tftp_request, xfer, tftp_xfer_operations );
+
 /**
  * Initiate TFTP/TFTM/MTFTP download
  *
@@ -1117,7 +1076,7 @@ static struct xfer_interface_operations tftp_xfer_operations = {
  * @v uri		Uniform Resource Identifier
  * @ret rc		Return status code
  */
-static int tftp_core_open ( struct xfer_interface *xfer, struct uri *uri,
+static int tftp_core_open ( struct interface *xfer, struct uri *uri,
 			    unsigned int default_port,
 			    struct sockaddr *multicast,
 			    unsigned int flags ) {
@@ -1135,10 +1094,9 @@ static int tftp_core_open ( struct xfer_interface *xfer, struct uri *uri,
 	if ( ! tftp )
 		return -ENOMEM;
 	ref_init ( &tftp->refcnt, tftp_free );
-	xfer_init ( &tftp->xfer, &tftp_xfer_operations, &tftp->refcnt );
-	xfer_init ( &tftp->socket, &tftp_socket_operations, &tftp->refcnt );
-	xfer_init ( &tftp->mc_socket, &tftp_mc_socket_operations,
-		    &tftp->refcnt );
+	intf_init ( &tftp->xfer, &tftp_xfer_desc, &tftp->refcnt );
+	intf_init ( &tftp->socket, &tftp_socket_desc, &tftp->refcnt );
+	intf_init ( &tftp->mc_socket, &tftp_mc_socket_desc, &tftp->refcnt );
 	timer_init ( &tftp->timer, tftp_timer_expired );
 	tftp->uri = uri_get ( uri );
 	tftp->blksize = TFTP_DEFAULT_BLKSIZE;
@@ -1159,7 +1117,7 @@ static int tftp_core_open ( struct xfer_interface *xfer, struct uri *uri,
 	start_timer_nodelay ( &tftp->timer );
 
 	/* Attach to parent interface, mortalise self, and return */
-	xfer_plug_plug ( &tftp->xfer, xfer );
+	intf_plug_plug ( &tftp->xfer, xfer );
 	ref_put ( &tftp->refcnt );
 	return 0;
 
@@ -1178,7 +1136,7 @@ static int tftp_core_open ( struct xfer_interface *xfer, struct uri *uri,
  * @v uri		Uniform Resource Identifier
  * @ret rc		Return status code
  */
-static int tftp_open ( struct xfer_interface *xfer, struct uri *uri ) {
+static int tftp_open ( struct interface *xfer, struct uri *uri ) {
 	return tftp_core_open ( xfer, uri, TFTP_PORT, NULL,
 				TFTP_FL_RRQ_SIZES );
 
@@ -1197,7 +1155,7 @@ struct uri_opener tftp_uri_opener __uri_opener = {
  * @v uri		Uniform Resource Identifier
  * @ret rc		Return status code
  */
-static int tftpsize_open ( struct xfer_interface *xfer, struct uri *uri ) {
+static int tftpsize_open ( struct interface *xfer, struct uri *uri ) {
 	return tftp_core_open ( xfer, uri, TFTP_PORT, NULL,
 				( TFTP_FL_RRQ_SIZES |
 				  TFTP_FL_SIZEONLY ) );
@@ -1217,7 +1175,7 @@ struct uri_opener tftpsize_uri_opener __uri_opener = {
  * @v uri		Uniform Resource Identifier
  * @ret rc		Return status code
  */
-static int tftm_open ( struct xfer_interface *xfer, struct uri *uri ) {
+static int tftm_open ( struct interface *xfer, struct uri *uri ) {
 	return tftp_core_open ( xfer, uri, TFTP_PORT, NULL,
 				( TFTP_FL_RRQ_SIZES |
 				  TFTP_FL_RRQ_MULTICAST ) );
@@ -1237,7 +1195,7 @@ struct uri_opener tftm_uri_opener __uri_opener = {
  * @v uri		Uniform Resource Identifier
  * @ret rc		Return status code
  */
-static int mtftp_open ( struct xfer_interface *xfer, struct uri *uri ) {
+static int mtftp_open ( struct interface *xfer, struct uri *uri ) {
 	return tftp_core_open ( xfer, uri, MTFTP_PORT,
 				( struct sockaddr * ) &tftp_mtftp_socket,
 				TFTP_FL_MTFTP_RECOVERY );