+#define IPV6_PMTUDISC_INTERFACE 4
+#define IPV6_PMTUDISC_OMIT 5
+
+#define IPV6_PREFER_SRC_TMP 0x0001
+#define IPV6_PREFER_SRC_PUBLIC 0x0002
+#define IPV6_PREFER_SRC_PUBTMP_DEFAULT 0x0100
+#define IPV6_PREFER_SRC_COA 0x0004
+#define IPV6_PREFER_SRC_HOME 0x0400
+#define IPV6_PREFER_SRC_CGA 0x0008
+#define IPV6_PREFER_SRC_NONCGA 0x0800