+#define ICMP_UNREACH_NET_UNKNOWN 6 /* unknown net */
+#define ICMP_UNREACH_HOST_UNKNOWN 7 /* unknown host */
+#define ICMP_UNREACH_ISOLATED 8 /* src host isolated */
+#define ICMP_UNREACH_NET_PROHIB 9 /* prohibited access */
+#define ICMP_UNREACH_HOST_PROHIB 10 /* ditto */
+#define ICMP_UNREACH_TOSNET 11 /* bad tos for net */
+#define ICMP_UNREACH_TOSHOST 12 /* bad tos for host */