+#define IP_DONT_FRAGMENT 0x4000 /* Don't fragment. */
+#define IP_MORE_FRAGMENTS 0x2000 /* More fragments. */
+#define IP_FRAG_OFF_MASK 0x1fff /* Fragment offset. */
+#define IP_IS_FRAGMENT(ip_frag_off) \
+ ((ip_frag_off) & htons(IP_MORE_FRAGMENTS | IP_FRAG_OFF_MASK))
+