Re: [PATCH nft 0/3] ruleset optimization infrastructure

[Arturo Borrero Gonzalez <arturo@netfilter.org>]

On 12/15/21 20:56, Pablo Neira Ayuso wrote:
> Hi,
> 
> This patchset adds a new -o/--optimize option to enable ruleset
> optimization.
> 

Thanks for working on this. From what I see in the community, this feature will 
be of high value to some folks: users often struggle with doing this kind of 
optimizations by hand.

> The ruleset optimization first loads the ruleset in "dry run" mode to
> validate that the original ruleset is correct. Then, on a second pass it
> performs the ruleset optimization before adding the rules into the
> kernel.
> 

Could you please describe how to work with this if all I want is to check how an 
optimized version of my ruleset would look like, but not load it into the kernel?

The use case would be: I just need a diff between my ruleset.nft file and 
whatever the optimized version would be, without performing any actual change.

Of course this can be added later on if not supported in this patch.

> This infrastructure collects the statements that are used in rules. Then,
> it builds a matrix of rules vs. statements. Then, it looks for common
> statements in consecutive rules that are candidate to be merged. Finally,
> it merges rules.

clever!

Is this infra extensible enough to support scanning non-adjacent rules in the 
future?

ie, being able to transform:

* ip daddr 1.1.1.1 counter accept
* tcp dport 80 accept
* ip daddr 2.2.2.2 counter accept

into:

* ip daddr { 1.1.1., 2.2.2.2 } counter accept
* tcp dport 80 accept