+#if BYTE_ORDER == BIG_ENDIAN
+#define hton64(x) (x)
+#define ntoh64(x) (x)
+#else /* BYTE_ORDER == BIG_ENDIAN */
+#define hton64(x) ((uint64_t) (htonl(((x) >> 32) & 0xffffffffLL)) | \
+ (uint64_t) ((htonl(x) & 0xffffffffLL) << 32))
+#define ntoh64(x) (hton64(x))
+#endif /* BYTE_ORDER == BIG_ENDIAN */
+