add err check

server_https.go

@@ -52,7 +52,9 @@ func (srv *server) handleHTTPReq(w http.ResponseWriter, r *http.Request) {
 	}
 	w.Header().Set("content-type", dnsMsgType)
 	d, _ := m.Pack()
-	w.Write(d)
+	if _, err := w.Write(d); err != nil {
+		log.Errorln(err)
+	}
 }
 
 func (srv *server) ServeHTTP(w http.ResponseWriter, r *http.Request) {

server_tcp.go

@@ -27,6 +27,9 @@ func (srv *server) handleTCP(c net.Conn) {
 		for _, a := range m.Answer {
 			log.Debugln("result", a.String())
 		}
-		conn.WriteMsg(m)
+		if err := conn.WriteMsg(m); err != nil {
+			log.Errorln(err)
+			break
+		}
 	}
 }

server_udp.go

@@ -24,5 +24,7 @@ func (srv *server) handleUDP(buf []byte, addr net.Addr, conn *net.UDPConn) {
 		log.Debugln("result", a.String())
 	}
 	d, _ := m.Pack()
-	conn.WriteTo(d, addr)
+	if _, err := conn.WriteTo(d, addr); err != nil {
+		log.Errorln(err)
+	}
 }