Re: [ethtool PATCH 2/2] Add RX packet classification interface

On 2/28/2011 4:35 PM, Ben Hutchings wrote:

On Tue, 2011-02-22 at 12:52 -0800, Alexander Duyck wrote:

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                                } else
                                        show_usage(1);
                                break;

I don't think the same options (-n, -N) should be used both for flow
hashing and n-tuple flow steering/filtering.  This command-line
interface and the structure used in the ethtool API just seem to reflect
the implementation in the niu driver.

(In fact I would much prefer it if the -u and -U options could be used
for both the rxnfc and rxntuple interfaces.  But I haven't thought about
how the differences in functionality would be exposed to or hidden from
the user.)

I was kind of thinking about merging the two interfaces too, but I was
looking at it more from the perspective of moving away from ntuple more
towards this newer interface.  My main motivation being that the filter
display option is so badly broken for ntuple that it would be easier to
make ntuple a subset of the flow classifier instead of the other way around.

What would you think of using the "flow-type" keyword to indicate legacy
ntuple support, and then adding something like "class-rule-add", and
"class-rule-del" to add support for the network flow classifier calls?

I really don't want to introduce different syntax for functionality that
is common between the two command sets.  The user should not have to
know that driver A implements interface I and driver B implements
interface J, except that since version 2.6.y driver A implements
interface J too.

Surely it is possible to try one interface, then the other, when the
requested filter can be implemented either way?

The problem is that the interfaces are different in the way they 
implement their masks.  N-tuple defines the mask as 0s mean inclusion, 
1s, mean exclusion.  The network flow classifier filters are the exact 
opposite.  As such we really need to know which type of filter we are 
dealing with before we start setting up values.  In addition there are 
options such as location which exist in network flow classifier rules, 
but not in ntuple rules.

Thanks,

Alex