[efi] Create VLAN autoboot device automatically

When chainloading iPXE from an EFI VLAN device, configure the
corresponding iPXE VLAN device to be created automatically.

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

src/interface/efi/efi_autoboot.c

diff --git a/src/interface/efi/efi_autoboot.c b/src/interface/efi/efi_autoboot.c
index ec7793c..a103c2f 100644
--- a/src/interface/efi/efi_autoboot.c
+++ b/src/interface/efi/efi_autoboot.c
@@ -25,6 +25,8 @@
 
 #include <string.h>
 #include <errno.h>
+#include <ipxe/if_ether.h>
+#include <ipxe/vlan.h>
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/efi_path.h>
 #include <ipxe/efi/efi_autoboot.h>
@@ -81,6 +83,13 @@
 		       efi_handle_name ( device ), vlan );
 	}
 
+	/* Configure automatic VLAN device, if applicable */
+	if ( vlan && ( mode->HwAddressSize == ETH_ALEN ) ) {
+		vlan_auto ( &mode->CurrentAddress, vlan );
+		DBGC ( device, "EFI %s configured automatic VLAN %d\n",
+		       efi_handle_name ( device ), vlan );
+	}
+
 	/* Close protocol */
 	bs->CloseProtocol ( device, &efi_simple_network_protocol_guid,
 			    efi_image_handle, NULL );