User variables on Src

[Wickedknight2]

    Hello rAthena. I am trying to make it so a skill can do pseudo Critical Damage. Was able to figure out how to make it so the skill damage will go higher based on the Critical Damage modifier, but can't find out the Critical chance variable.
This is the script so far:
 

            if(rnd()%100 <= sstatus->cri)
            skillratio += skillratio * sd->bonus.crit_atk_rate/100;