#define ARPHRD_PHONET 820 /* PhoNet media type */
#define ARPHRD_PHONET_PIPE 821 /* PhoNet pipe header */
#define ARPHRD_CAIF 822 /* CAIF media type */
+#define ARPHRD_IP6GRE 823 /* GRE over IPv6 */
#define ARPHRD_VOID 0xFFFF /* Void type, nothing is known */
#define ARPHRD_NONE 0xFFFE /* zero header length */