fix resolver for ipv6

cmd/gost/cmd.go

@@ -242,7 +242,8 @@ func buildConfigFromCmd(services, nodes stringList) (*config.Config, error) {
 				resolverCfg.Nameservers = append(
 					resolverCfg.Nameservers,
 					&config.NameserverConfig{
-						Addr: rs,
+						Addr:   rs,
+						Prefer: metadata.GetString(md, "prefer"),
 					},
 				)
 			}

cmd/gost/main.go

@@ -56,6 +56,9 @@ func main() {
 	var err error
 	if len(services) > 0 || apiAddr != "" {
 		cfg, err = buildConfigFromCmd(services, nodes)
+		if err != nil {
+			log.Fatal(err)
+		}
 		if debug && cfg != nil {
 			if cfg.Log == nil {
 				cfg.Log = &config.LogConfig{}
@@ -78,9 +81,9 @@ func main() {
 		} else {
 			err = cfg.Load()
 		}
-	}
-	if err != nil {
-		log.Fatal(err)
+		if err != nil {
+			log.Fatal(err)
+		}
 	}
 
 	log = logFromConfig(cfg.Log)