Hi,
On Thu, 12 May 2016 14:45:36 -0700 Tom Herbert <t...@herbertland.com> wrote:
> On Thu, May 12, 2016 at 1:23 PM, Shmulik Ladkani
> <shmulik.ladk...@gmail.com> wrote:
> >> @@ -222,13 +222,14 @@ static int ip6_input_finish(struct net *net, struct
> >> sock *sk, struct sk_buff *sk
> >> */
> >>
> >> rcu_read_lock();
> >> -resubmit:
> >> +
> >> idev = ip6_dst_idev(skb_dst(skb));
> >> if (!pskb_pull(skb, skb_transport_offset(skb)))
> >> goto discard;
> >> nhoff = IP6CB(skb)->nhoff;
> >> nexthdr = skb_network_header(skb)[nhoff];
> >>
> >> +resubmit:
> >
> > This has already been attempted in 0243508edd "ipv6: Fix protocol
> > resubmission" and reverted in 1b0ccfe54a.
> >
> > It looks that in some genuine extension header handling cases of ipv6
> > (not related to encapsulation), the original resubmission code REALLY
> > requires one to re-read IP6CB(skb)->nhoff and refetch the nexthdr.
> >
> Is there any reason why the EH handlers can't read the nexthdr and return
> that?
One additional thing:
Seems the
if (!pskb_pull(skb, skb_transport_offset(skb)))
located at the original resubmit label was also necessary, as the EH
handlers may increment skb->transport_header (both ipv6_destopt_rcv and
ipv6_rthdr_rcv do so).
So if we'd like to read the nexthdr at the EH handlers we should repeat
the "skb pull; read nexthdr from skb_network_header(skb)[new nhoff];
return nexhdr;" prior each positive return from EH handlers.
Thanks
Shmulik
