Re: [PATCH 2/3] evaluate: allow to use string with binary operations

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Wed, Jan 15, 2014 at 10:29:43AM +0100, Pablo Neira Ayuso wrote:
> On Tue, Jan 14, 2014 at 03:49:00PM +0000, Patrick McHardy wrote:
> > Well, I think the easiest approach would be to add some code to
> > expr_evaluate_relational() for OP_EQ for convert the LHS of a
> > relational meta expression to LHS & RHS:
> > 
> >      relational (==)
> >     /               \
> > meta oifname       string
> > 
> > =>
> > 
> >         relational (==)
> >        /               \
> >     binop (&)        string
> >   /          \
> > meta oifname  string
> > 
> > The attached patch uses '*' as a trigger (and obviously won't work
> > because the '*' is also used in the mask, but you get the idea.
> > netlink_delinarize adjustments are missing, but it should be pretty
> > trivial to add the corresponding code to postprocessing of relational
> > expressions.
> 
> Oh yes, with that wildcard trick the thing is simplified. There was
> some discuss on the use of '+' that seems to be possible to be used in
> a device name. I guess '*' is safe as udev is using it in their rules.

It seems we need to include the '*' into the string rule in flex for
this. We already have a single '*' that is used in the parser for
prefixes, I think that may lead to ambiguity problems.