package tunnel import ( "github.com/cloudflare/cloudflared/tunneldns" "gopkg.in/urfave/cli.v2" "github.com/pkg/errors" ) func runDNSProxyServer(c *cli.Context, dnsReadySignal, shutdownC chan struct{}) error { port := c.Int("proxy-dns-port") if port <= 0 || port > 65535 { logger.Errorf("The 'proxy-dns-port' must be a valid port number in <1, 65535> range.") return errors.New("The 'proxy-dns-port' must be a valid port number in <1, 65535> range.") } listener, err := tunneldns.CreateListener(c.String("proxy-dns-address"), uint16(port), c.StringSlice("proxy-dns-upstream")) if err != nil { close(dnsReadySignal) listener.Stop() logger.WithError(err).Error("Cannot create the DNS over HTTPS proxy server") return errors.Wrap(err, "Cannot create the DNS over HTTPS proxy server") } err = listener.Start(dnsReadySignal) if err != nil { logger.WithError(err).Error("Cannot start the DNS over HTTPS proxy server") return errors.Wrap(err, "Cannot start the DNS over HTTPS proxy server") } <-shutdownC listener.Stop() return nil }