From mboxrd@z Thu Jan  1 00:00:00 1970
From: Simon Horman <simon.horman@netronome.com>
Subject: Re: [PATCH iproute2 net-next] tc: flower: support matching flags
Date: Wed, 4 Jan 2017 11:33:03 +0100
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Cc: Jiri Benc <jbenc@redhat.com>, netdev@vger.kernel.org,
        Stephen Hemminger <stephen@networkplumber.org>,
        "David S. Miller" <davem@davemloft.net>,
        Hadar Hen Zion <hadarh@mellanox.com>,
        Or Gerlitz <ogerlitz@mellanox.com>,
        Roi Dayan <roid@mellanox.com>
To: Paul Blakey <paulb@mellanox.com>
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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.