Re: [PATCH iproute2 net-next] tc: flower: support matching flags

[Paul Blakey <paulb@mellanox.com>]

On 04/01/2017 12:33, Simon Horman wrote:
> On Tue, Jan 03, 2017 at 01:54:34PM +0200, Paul Blakey wrote:
>
> ...
>
> Hi Paul,
>
>> Matching name was from the idea that we are doing is matching.
>> And regarding documentation/flag names I didn't want tc tool to be need of a
>> update each time a new flag is introduced,
>> But I guess I can add two options like with ip_proto where you can specify
>> known flags by name but can also give a value.
>> What do you think about that?
>>
>> flags <FLAGS> / <HEX'/'HEX>
>> FLAGS => frag/no_frag/tcp_syn/no_tcp_syn ['|'<FLAGS>]*
>> e.g: flags frag|no_tcp_syn or flags 0x01/0x15
>> and the mask will have a on bits corresponds only to those flags specified.
> I suppose a flag is a flag and bitwise masking allows arbitrary matching
> on one or more flags. But I wonder if, as per your example above,
> it makes sense to mix IP (frag) and TCP flags in the same field of the
> classifier.
It mimics the kernel packing of flags, I have no problem either way 
(flags, or ip_flags/tcp_flags pairs), what do you think jiri?