netfilter: xt_TEE: resolve oif using netdevice notifiers

Replace the runtime oif name resolving by netdevice notifier based
resolving. When an oif is given, a netdevice notifier is registered
to resolve the name on NETDEV_REGISTER or NETDEV_CHANGE and unresolve
it again on NETDEV_UNREGISTER or NETDEV_CHANGE to a different name.

Signed-off-by: Patrick McHardy <kaber@trash.net>

include/linux/netfilter/xt_TEE.h

@@ -4,6 +4,9 @@
 struct xt_tee_tginfo {
 	union nf_inet_addr gw;
 	char oif[16];
+
+	/* used internally by the kernel */
+	struct xt_tee_priv *priv __attribute__((aligned(8)));
 };
 
 #endif /* _XT_TEE_TARGET_H */