move IsHostnameLocal to common/util

proxy/lib/snowflake.go

@@ -172,25 +172,6 @@ func isRemoteAddress(ip net.IP) bool {
 	return !(util.IsLocal(ip) || ip.IsUnspecified() || ip.IsLoopback())
 }
 
-// Checks whether the hostname is local
-func isHostnameLocal(hostname string) bool {
-	// Per https://en.wikipedia.org/wiki/Special-use_domain_name
-	tlds := []string{
-		".internal",
-		".invalid",
-		".local",
-		".localhost",
-		".onion",
-		".test",
-	}
-	for _, tld := range tlds {
-		if strings.HasSuffix(hostname, tld) {
-			return true
-		}
-	}
-	return hostname == "localhost"
-}
-
 func genSessionID() string {
 	buf := make([]byte, sessionIDLength)
 	_, err := rand.Read(buf)
@@ -690,7 +671,7 @@ func checkIsRelayURLAcceptable(
 	}
 	if !allowPrivateIPs {
 		hostname := parsedRelayURL.Hostname()
-		if isHostnameLocal(hostname) {
+		if util.IsHostnameLocal(hostname) {
 			return fmt.Errorf("rejected Relay URL: private hostnames are not allowed")
 		}
 		ipArray, err := net.LookupIP(hostname)