[autoboot] Include VLAN tag in filter for identifying autoboot device

When chainloading iPXE from a VLAN device, the MAC address of the
loaded image's device handle will match the MAC address of the trunk
device created by iPXE, and the autoboot process will then erroneously
consider the trunk device to be an autoboot device.

Fix by recording the VLAN tag along with the MAC address, and treating
the VLAN tag as part of the filter used to match the MAC address
against candidate network devices.

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

src/include/ipxe/efi/efi_autoboot.h

@@ -11,6 +11,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 #include <ipxe/efi/efi.h>
 
-extern int efi_set_autoboot_ll_addr ( EFI_HANDLE device );
+extern int efi_set_autoboot_ll_addr ( EFI_HANDLE device,
+				      EFI_DEVICE_PATH_PROTOCOL *path );
 
 #endif /* _IPXE_EFI_AUTOBOOT_H */

src/include/usr/autoboot.h

@@ -28,7 +28,8 @@ enum uriboot_flags {
 
 extern void set_autoboot_busloc ( unsigned int bus_type,
 				  unsigned int location );
-extern void set_autoboot_ll_addr ( const void *ll_addr, size_t len );
+extern void set_autoboot_ll_addr ( const void *ll_addr, size_t len,
+				   unsigned int vlan );
 
 extern int uriboot ( struct uri *filename, struct uri **root_paths,
 		     unsigned int root_path_count, int drive,

src/interface/efi/efi_autoboot.c

@@ -26,6 +26,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <string.h>
 #include <errno.h>
 #include <ipxe/efi/efi.h>
+#include <ipxe/efi/efi_path.h>
 #include <ipxe/efi/efi_autoboot.h>
 #include <ipxe/efi/Protocol/SimpleNetwork.h>
 #include <usr/autoboot.h>
@@ -40,9 +41,11 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  * Identify autoboot device
  *
  * @v device		Device handle
+ * @v path		Device path
  * @ret rc		Return status code
  */
-int efi_set_autoboot_ll_addr ( EFI_HANDLE device ) {
+int efi_set_autoboot_ll_addr ( EFI_HANDLE device,
+			       EFI_DEVICE_PATH_PROTOCOL *path ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	union {
 		EFI_SIMPLE_NETWORK_PROTOCOL *snp;
@@ -50,6 +53,7 @@ int efi_set_autoboot_ll_addr ( EFI_HANDLE device ) {
 	} snp;
 	EFI_SIMPLE_NETWORK_MODE *mode;
 	EFI_STATUS efirc;
+	unsigned int vlan;
 	int rc;
 
 	/* Look for an SNP instance on the image's device handle */
@@ -66,10 +70,16 @@ int efi_set_autoboot_ll_addr ( EFI_HANDLE device ) {
 
 	/* Record autoboot device */
 	mode = snp.snp->Mode;
-	set_autoboot_ll_addr ( &mode->CurrentAddress, mode->HwAddressSize );
+	vlan = efi_path_vlan ( path );
+	set_autoboot_ll_addr ( &mode->CurrentAddress, mode->HwAddressSize,
+			       vlan );
 	DBGC ( device, "EFI %s found autoboot link-layer address:\n",
 	       efi_handle_name ( device ) );
 	DBGC_HDA ( device, 0, &mode->CurrentAddress, mode->HwAddressSize );
+	if ( vlan ) {
+		DBGC ( device, "EFI %s found autoboot VLAN %d\n",
+		       efi_handle_name ( device ), vlan );
+	}
 
 	/* Close protocol */
 	bs->CloseProtocol ( device, &efi_simple_network_protocol_guid,

src/interface/efi/efiprefix.c

@@ -81,7 +81,7 @@ static void efi_init_application ( void ) {
 	EFI_DEVICE_PATH_PROTOCOL *path = efi_loaded_image_path;
 
 	/* Identify autoboot device, if any */
-	efi_set_autoboot_ll_addr ( device );
+	efi_set_autoboot_ll_addr ( device, path );
 
 	/* Store cached DHCP packet, if any */
 	efi_cachedhcp_record ( device, path );

src/usr/autoboot.c

@@ -27,6 +27,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <stdio.h>
 #include <errno.h>
 #include <ipxe/netdevice.h>
+#include <ipxe/vlan.h>
 #include <ipxe/dhcp.h>
 #include <ipxe/settings.h>
 #include <ipxe/image.h>
@@ -57,6 +58,9 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 /** Link-layer address of preferred autoboot device, if known */
 static uint8_t autoboot_ll_addr[MAX_LL_ADDR_LEN];
 
+/** VLAN tag of preferred autoboot device, if known */
+static unsigned int autoboot_vlan;
+
 /** Device location of preferred autoboot device, if known */
 static struct device_description autoboot_desc;
 
@@ -494,8 +498,9 @@ void set_autoboot_busloc ( unsigned int bus_type, unsigned int location ) {
  */
 static int is_autoboot_ll_addr ( struct net_device *netdev ) {
 
-	return ( memcmp ( netdev->ll_addr, autoboot_ll_addr,
-			  netdev->ll_protocol->ll_addr_len ) == 0 );
+	return ( ( memcmp ( netdev->ll_addr, autoboot_ll_addr,
+			    netdev->ll_protocol->ll_addr_len ) == 0 ) &&
+		 ( vlan_tag ( netdev ) == autoboot_vlan ) );
 }
 
 /**
@@ -503,14 +508,19 @@ static int is_autoboot_ll_addr ( struct net_device *netdev ) {
  *
  * @v ll_addr		Link-layer address
  * @v len		Length of link-layer address
+ * @v vlan		VLAN tag
  */
-void set_autoboot_ll_addr ( const void *ll_addr, size_t len ) {
+void set_autoboot_ll_addr ( const void *ll_addr, size_t len,
+			    unsigned int vlan ) {
 
 	/* Record autoboot link-layer address (truncated if necessary) */
 	if ( len > sizeof ( autoboot_ll_addr ) )
 		len = sizeof ( autoboot_ll_addr );
 	memcpy ( autoboot_ll_addr, ll_addr, len );
 
+	/* Record autoboot VLAN tag */
+	autoboot_vlan = vlan;
+
 	/* Mark autoboot device as present */
 	is_autoboot_device = is_autoboot_ll_addr;
 }