-#define TNL_F_PMTUD (1 << 3) /* Enable path MTU discovery. */
-#define TNL_F_HDR_CACHE (1 << 4) /* Enable tunnel header caching. */
-#define TNL_F_IPSEC (1 << 5) /* Traffic is IPsec encrypted. */
+#define TNL_F_DF_INHERIT (1 << 3) /* Inherit the DF bit from the inner packet. */
+#define TNL_F_DF_DEFAULT (1 << 4) /* Set the DF bit if inherit off or not IP. */
+#define TNL_F_PMTUD (1 << 5) /* Enable path MTU discovery. */
+#define TNL_F_HDR_CACHE (1 << 6) /* Enable tunnel header caching. */
+#define TNL_F_IPSEC (1 << 7) /* Traffic is IPsec encrypted. */