NFNL_NFA_NEST

[Jozsef Kadlecsik]

Hi Patrick,

On Wed, 21 Mar 2007, Patrick McHardy wrote:

> One of the worst mistakes in nfnetlink in my opinion was the
> introduction of the NFNL_NFA_NEST bit. It prevents us from
> using a large part of the generic netlink stuff, since that
> just interprets it as a really huge attribute type. Since
> its not used even for anything, this is really annoying.

Pablo helped me to work on porting ipset from sockopt to nfnetlink (which 
is still not finished yet :-() and I nagged Pablo a lot to use nesting, 
primarily to hide sub-module details at netlink message level from the 
ipset core. For example when adding/deleting/testing a set, the netlink 
message looks like this:

<set name>
<set type>
<nested: set type specific data>

so that the core is not burdened by module-dependent details.

The other place where I wanted to use nesting is to send a bunch of the 
same type data in one netlink message instead of sending every one of them 
in separated messages: I shudder to send ~370 netlink messages instead of 
a single one in order to pass that number of IP addresses.

Best regards,
Jozsef
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