diff --git a/net/6lowpan/6lowpan_i.h b/net/6lowpan/6lowpan_i.h
index d16bb4b14aa1d8e99fb1c8d215987cf333c5486d..97ecc27aeca695da7de57e66ac741663095886a1 100644
--- a/net/6lowpan/6lowpan_i.h
+++ b/net/6lowpan/6lowpan_i.h
@@ -3,6 +3,15 @@
 
 #include <linux/netdevice.h>
 
+#include <net/6lowpan.h>
+
+/* caller need to be sure it's dev->type is ARPHRD_6LOWPAN */
+static inline bool lowpan_is_ll(const struct net_device *dev,
+				enum lowpan_lltypes lltype)
+{
+	return lowpan_dev(dev)->lltype == lltype;
+}
+
 #ifdef CONFIG_6LOWPAN_DEBUGFS
 int lowpan_dev_debugfs_init(struct net_device *dev);
 void lowpan_dev_debugfs_exit(struct net_device *dev);