+unsigned int
+parse_netmask_string(const char *str, bool v6)
+{
+ struct in_addr addr;
+ unsigned int ret;
+ char *err = NULL;
+
+ if (!strchr(str, '.')) {
+ ret = strtoul(str, &err, 0);
+ if (err && *err)
+ goto error;
+
+ return ret;
+ }
+
+ if (v6)
+ goto error;
+
+ if (inet_aton(str, &addr) != 1)
+ goto error;
+
+ return 32 - fls(~(ntohl(addr.s_addr)));
+
+error:
+ return ~0;
+}
+