pfSense

If you are shifting the scale to the range 1..6, the statement where you set the default value to 2 is incorrect. When I copy it to a test box, it ends up setting the default to Audit, when the strongswan default is equivalent to control. The strongswan default on the range from -1 to 4 is 1 (the third value). Your new default should be 3.

The statements in the input validation section at the top will all need to have their ranges adjusted as well. You could probably replace those 16 if statements that check each individual log setting with a loop to do the same thing:

        foreach ($ipsec_loglevels as $lkey => $ldescr) {

                if (isset($pconfig["ipsec_{$lkey}"]) && !in_array(intval($pconfig["ipsec_{$lkey}"]), range(-1, 4))) {
                        $input_errors[] = "A valid value must be specified for {$ldescr} debug.";
                }
        }