Re: [PATCH nft] scanner: disable most rules when we expect literal symbol

[Florian Westphal <fw@strlen.de>]

Florian Westphal <fw@strlen.de> wrote:
> nft fails to parse certain corner-cases, for example:
> 
> nft add rule filter input meta rtclassid daddr
> 
> ... as it finds DADDR token.  However, 'daddr' might be a valid
> routing realm listed in iproute2/rt_realms, so this should be allowed.
> 
> Pablo suggested to change the start conditions in the scanner
> accordingly.
> 
> After this patch, the following rule works:
> 
> ct label & (foobar | saddr) == saddr ip saddr 1.2.3.4 rtclassid { 42, cosmos, rule}

Note that this will not work:

ct label eq foobar

(we disabled eq token, eq is expected to be name of label).

&, ==, !=, etc. will continue to work.

Not sure if thats a bug or feature -- it would be easy to just
remove the <INITIAL> from "eq" so that we continue to recognize
it as "==", but it means that its not possible to use eq, lt, gt,
and so on as usernames, rtclassids, etc etc.