Help on insert_fragment() in ipv4defrag.c

Is the code putting the fragments in ascending/descending order..but while trying to understand the code, I felt like there is no particular order..also can anyone explain why the comment 'Based on 4.3 BSD, we will give priority to fragments with lower offset to avoid teardrop attack' 

I am not sure is this the right forum to ask doubts..if not where to post queries regarding libntoh