Re: Avoiding multiple calls to xt_target.checkentry

[Patrick McHardy <kaber@trash.net>]

Adam Nielsen wrote:
>>> In other words, is there a function only called the first time the rule is
>>> added by iptables?  Or should I be keeping track of that myself?
>> You forget that iptables does not add rules. It replaces entire tables,
>> and to make that atomic, the new table is checked before the old one
>> is released. And yes, you usually try to lookup a led trigger first
>> before creating one, because there can be a table that calls -j LED
>> twice.
> 
> Thanks for the explanation!  So - to get it straight in my mind - the
> checkentry function will be called multiple times while the trigger exists,
> but is the destroy function also called multiple times?  Or is checkentry
> called whenever tables are created, but destroy only ever called once when the
> table is removed for the last time?

They will always be called an equal amount of times - each one
once per target instance.