+
+/*
+ * Extended TCP MD5 signature option. This option allows TCP MD5 to be enabled
+ * on prefixes.
+ *
+ * sock
+ * Socket to enable option on.
+ *
+ * su
+ * Sockunion specifying address (or prefix) to enable option on.
+ *
+ * prefixlen
+ * 0 - su is an address; fall back to non-extended mode
+ * Else - su is a prefix; prefixlen is the mask length
+ *
+ * password
+ * MD5 auth password
+ */
+extern int sockopt_tcp_signature_ext(int sock, union sockunion *su,
+ uint16_t prefixlen, const char *password);
+
+#ifdef __cplusplus
+}
+#endif
+