handler: close rejected connections properly

Updated the connection listener to close the rejections that happen due
to IP, properly with the proper status code

handler/handler.go

@@ -17,7 +17,7 @@ type ConnectionHandler interface {
 	Handle(logger *logging.Logger)
 }
 
-func writeResponse(out io.Writer, version string, status string, header http.Header) error {
+func WriteResponse(out io.Writer, version string, status string, header http.Header) error {
 	var builder strings.Builder
 	if _, err := builder.WriteString(fmt.Sprintf("%s %s\n", version, status)); err != nil {
 		return err

handler/proxyhandler.go

@@ -88,7 +88,7 @@ func (p *ProxyHandler) Handle(logger *logging.Logger) {
 
 		// check the authorization
 		if !checkAuthorization(p.cfg, req) {
-			if err := writeResponse(
+			if err := WriteResponse(
 				p.incoming,
 				req.Proto,
 				"407 Proxy Authentication Required",

handler/tunnelhandler.go

@@ -49,7 +49,7 @@ func (h *TunnelHandler) Handle(logger *logging.Logger) {
 	}
 	// check the authorization
 	if !checkAuthorization(h.cfg, req) {
-		if err := writeResponse(
+		if err := WriteResponse(
 			h.incoming,
 			req.Proto,
 			"407 Proxy Authentication Required",

tunnelify.go

@@ -53,6 +53,7 @@ func (s *Server) Start() error {
 
 		// check if allowed
 		if !s.config.ShouldAllowIP(c.RemoteAddr().String()) {
+			handler.WriteResponse(c, "HTTP/1.1", "403 Forbidden", nil)
 			c.Close()
 			continue
 		}