Function tcpTLSCheck

internal/healthcheck/checker.go:189–225

(ctx context.Context, dialer *net.Dialer, targetAddress string)

}

func tcpTLSCheck(ctx context.Context, dialer *net.Dialer, targetAddress string) error {
	// TODO use mullvad API if current provider is Mullvad

	address, err := makeAddressToDial(targetAddress)
	if err != nil {
		return err
	}

	const dialNetwork = "tcp4"
	connection, err := dialer.DialContext(ctx, dialNetwork, address)
	if err != nil {
		return fmt.Errorf("dialing: %w", err)
	}

	if strings.HasSuffix(address, ":443") {
		host, _, err := net.SplitHostPort(address)
		if err != nil {
			return fmt.Errorf("splitting host and port: %w", err)
		}
		tlsConfig := &tls.Config{
			MinVersion: tls.VersionTLS12,
			ServerName: host,
		}
		tlsConnection := tls.Client(connection, tlsConfig)
		err = tlsConnection.HandshakeContext(ctx)
		if err != nil {
			return fmt.Errorf("running TLS handshake: %w", err)
		}
	}

	err = connection.Close()
	if err != nil {
		return fmt.Errorf("closing connection: %w", err)
	}

	return nil
}

func makeAddressToDial(address string) (addressToDial string, err error) {
	host, port, err := net.SplitHostPort(address)