fix DNS forword issue, inspired by skydns

router/dns.go

@@ -52,6 +52,9 @@ func (r *Router) ServeDNS(w dns.ResponseWriter, req *dns.Msg) {
 	default:
 		conn.Close()
 	}
+
+	resp.Id = req.Id
+	resp.Compress = true
 	w.WriteMsg(resp)
 }
 

router/router.go

@@ -138,5 +138,5 @@ func (r *Router) ProxyHandle(conn net.Conn, domain string, port uint16) error {
 
 func (r *Router) DirectHandle(conn net.Conn, addr string) error {
 	dur, err := util.RelayTo(conn, addr)
-	return errors.Wrapf(err, "direct relay to (%s), spend (%s)", addr, dur)
+	return errors.Wrapf(err, "spend (%s)", dur)
 }

util/relay.go

@@ -18,7 +18,7 @@ func RelayTo(conn net.Conn, addr string) (dur time.Duration, err error) {
 	start := time.Now()
 	rc, err := net.DialTimeout("tcp", addr, 5*time.Second)
 	if err != nil {
-		return time.Since(start), errors.Wrapf(err, "dial %s", addr)
+		return time.Since(start), errors.WithStack(err)
 	}
 	defer rc.Close()