Re: [RFC v4] Add TCP encap_rcv hook (repost)

[Simon Horman <horms-/R6kz+dDXgpPR4JQBCEnsQ@public.gmane.org>]

On Sun, Apr 22, 2012 at 08:24:35AM -0700, Stephen Hemminger wrote:
> 
> 
> > This hook is based on a hook of the same name provided by UDP.  It
> > provides
> > a way for to receive packets that have a TCP header and treat them in
> > some
> > alternate way.
> > 
> > It is intended to be used by an implementation of the STT tunneling
> > protocol within Open vSwtich's datapath. A prototype of such an
> > implementation has been made.
> > 
> > The STT draft is available at
> > http://tools.ietf.org/html/draft-davie-stt-01
> > 
> > My prototype STT implementation has been posted to the
> > dev-UOEtcQmXneFl884UGnbwIQ@public.gmane.org
> > The second version can be found at:
> > http://www.mail-archive.com/dev-yBygre7rU0TnMu66kgdUjQ@public.gmane.org/msg09001.html
> > It needs to be updated to call tcp_encap_enable()
> > 
> > Cc: Eric Dumazet <eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > Signed-off-by: Simon Horman <horms-/R6kz+dDXgpPR4JQBCEnsQ@public.gmane.org>
> > 
> >
> > +static struct static_key tcp_encap_needed __read_mostly;
> > +void tcp_encap_enable(void)
> > +{
> > +	if (!static_key_enabled(&tcp_encap_needed))
> > +		static_key_slow_inc(&tcp_encap_needed);
> > +}
> > +EXPORT_SYMBOL(tcp_encap_enable);
> 
> I have reservations about adding such a hook. but if we
> must, then the hook must be GPL only.

Sure, I have no objections there.