Re: [patch net-next v3] tc: introduce OpenFlow classifier

[Daniel Borkmann <daniel@iogearbox.net>]

On 04/10/2015 11:12 AM, Jiri Pirko wrote:
...
>> However I am sure that I majorly object to having yet another flow
>> parsing engine.  Therefore, at least adjust this code to use our flow
>> dissector and datastructures.  Adjust the flow dissector to fit your
>> needs, if necessary.
>
> Yep, Thomas already suggested the merge. The thing is, cls_flow uses
> linked list for doing lookups. That is not scalable. in cls_openflow I
> use rhashtable. Using rhashtable in cls_flow would break the existing
> assumption that first inrested filter would be first hit.
>
> So that would lead into major dual code in cls_flow. So I believe that
> it is better to do it in separate cls_openflow (do one thing and do it
> right).

Would it be possible to 1) reuse the majority of the existing internal
cls_flow code as much as possible, integrate the remaining openflow
parts into it, and then 2) just register a 2nd classifier kind, a la ...

static struct tcf_proto_ops cls_flow_ht_ops __read_mostly = {
	.kind		= "flow-ht",
	.classify	= flow_classify_ht,
	.init		= flow_init,
	.destroy	= flow_destroy,
	.change		= flow_change,
	.delete		= flow_delete,
	.get		= flow_get,
	.dump		= flow_dump,
	.walk		= flow_walk,
	.owner		= THIS_MODULE,
};

... so you could do the non-linear rhashtable matching from there, but
without much duplication?