--- src/VBox/HostDrivers/VBoxNetFlt/freebsd/Makefile.orig	2020-07-09 16:57:01 UTC
+++ src/VBox/HostDrivers/VBoxNetFlt/freebsd/Makefile
@@ -41,7 +41,7 @@ SRCS = \
 	SUPR0IdcClient.c \
 	SUPR0IdcClientComponent.c
 
-SRCS += device_if.h bus_if.h opt_netgraph.h
+SRCS += device_if.h bus_if.h opt_netgraph.h vnode_if.h
 
 .include <bsd.kmod.mk>