Fix vbox network interface error in linux 3.11. Patch taken from upstream at ticket #12001
Index: virtualbox/src/VBox/HostDrivers/VBoxNetFlt/linux/VBoxNetFlt-linux.c
===================================================================
--- virtualbox.orig/src/VBox/HostDrivers/VBoxNetFlt/linux/VBoxNetFlt-linux.c	2013-09-13 13:16:20.016285000 -0400
+++ virtualbox/src/VBox/HostDrivers/VBoxNetFlt/linux/VBoxNetFlt-linux.c	2013-09-13 13:22:15.460285000 -0400
@@ -1804,7 +1804,11 @@
 
 {
     PVBOXNETFLTINS      pThis = VBOX_FLT_NB_TO_INST(self);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 11, 0)
+    struct net_device  *pDev  = netdev_notifier_info_to_dev(ptr);
+#else
     struct net_device  *pDev  = (struct net_device *)ptr;
+#endif
     int                 rc    = NOTIFY_OK;
 
     Log(("VBoxNetFlt: got event %s(0x%lx) on %s, pDev=%p pThis=%p pThis->u.s.pDev=%p\n",