Re: [ovs-dev] [PATCH net-next v8] net: openvswitch: IPv6: Add IPv6 extension header support

[Jakub Kicinski]

On Wed, 9 Mar 2022 14:43:07 +0100 Ilya Maximets wrote:
> >> It's a bit of an uncharted territory, hard to say what's right.
> >> It may be a little easier to code up the rejection if we have
> >> the types defined (which I think we need to do in
> >> __parse_flow_nlattrs()? seems OvS does its own nla parsing?)  
> 
> Ack.  And, yes, __parse_flow_nlattrs() seems to be the right spot.
> OVS has lots of nested attributes with some special treatment in a
> few cases and dependency tracking, AFAICT, so it parses attributes
> on it's own.  Is there a better way?

Looks like OvS has extra requirements like attributes can't be
duplicated and zeroed out attrs are ignored. I don't think generic
parsers can do that today, although the former seems like a useful
addition.

A problem for another time.

> >> Johannes, any preference?
> >
> > so why not again just flat enum without ifdefs and without values
> > commented out? even if we leave values in comments like above it doesn't
> > mean the userspace won't use them by mistake and send to the kernel.
> > but the kernel will probably ignore as not being used and at least
> > there won't be a conflict again even if by mistake.. and it's easiest
> > to read.  
> 
> OK.  Seems like we have some votes and a reason (explicit reject) to have
> them defined.  This will also make current user space and kernel definitions
> equal.  Let me put together a patch and we'll continue the discussion there.

Thanks!