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

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.