Cost of rule groups vs sequential rules

How expensive is it to process a head rule vs a regular rule?

I have a rather lengthy set of rules for a blacklist and have rule groups
that breaks up a long list of CIDRs by their first octet.  It's getting
hairy trying to manage this growing list by hand so I wrote a script
to automatically break up a long list of CIDRs with varying mask sizes
into a "balanced" tree of rule groups where it partitions a list into
two lists of roughly the same size, then recurses the algorithm
on the sublists.

One of the tweakable parameters I have is the theshold where I stop
partitioning and just dump the list as a sequential set of rules, which
depends on the relative cost of processing head rules vs regular
pass/block rules.

Joseph Tam <[email protected]>