Hi Pablo,
> > +static int vrf_output6_direct_finish(struct net *net, struct sock *sk,
> > + struct sk_buff *skb)
> > +{
> > + vrf_finish_direct(skb);
> > +
> > + return vrf_ip6_local_out(net, sk, skb);
> > +}
> > +
> > static int vrf_output6_direct(struct net *net, struct sock *sk,
> > struct sk_buff *skb)
> > {
> > + int err = 1;
> > +
> > skb->protocol = htons(ETH_P_IPV6);
> >
> > - return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
> > - net, sk, skb, NULL, skb->dev,
> > - vrf_finish_direct,
> > - !(IPCB(skb)->flags & IPSKB_REROUTED));
> > + if (!(IPCB(skb)->flags & IPSKB_REROUTED))
> > + err = nf_hook(NFPROTO_IPV6, NF_INET_POST_ROUTING, net, sk, skb,
> > + NULL, skb->dev, vrf_output6_direct_finish);
>
> I might missing something... this looks very similar to NF_HOOK_COND
> but it's open-coded.
>
> My question, could you still use NF_HOOK_COND?
>
> ret = NF_HOOK_COND(NFPROTO_IPV6, ..., vrf_output6_direct_finish);
>
> just update the okfn.
I don't think this will work. The point of the patch is to have
different paths for sync and async Netfilter rules: In the async case
we call vrf_output6_direct_finish() to additionally do dst_output(). In
the (existing) synchronous path we just do vrf_finish_direct() and let
the caller do the dst_output().
If we prefer a common okfn(), we could return 0 to omit dst_output() in
ip/ip6_local_out(). This changes/extends the call stack for the common
case, though, and this is what I've tried to avoid.
> > + if (likely(err == 1))
>
> I'd suggest you remove likely() here and elsewhere in this patch.
> Just let the branch predictor make its work instead of assuming that
> the ruleset accepts traffic.
The likely() may be questionable, but I seems that is done in most
places when checking for synchronous Netfilter completion. But I'm fine
with changing these hunks, if you prefer.
Thanks,
Martin
