Re: [Bridge] RE: [VLAN] Re: [PATCH/RFC] Let {ip, arp}tables "see" bridged VLAN tagged{I,AR}P packets

[Ben Greear <greearb@xxxxxxxxxxxxxxx>]

Christian Darnell wrote:
> -----Original Message-----
>
> > From: Tommy Christensen [mailto:tommy.christensen@xxxxxxxxx]
> > Sent: Wednesday, October 08, 2003 10:09 AM
> > To: Christian Darnell
> > Cc: 'Linux 802.1Q VLAN'; Bart De Schuymer; netdev@xxxxxxxxxxx; bridge
> > Subject: Re: [Bridge] RE: [VLAN] Re: [PATCH/RFC] Let {ip, arp}tables
> > "see" bridged VLAN tagged{I,AR}P packets
> >
> >
> >
> > This is because the VLAN code is mangling shared data.
> > You need to do something like this:
> >
> >
> > --- linux-2.4/net/8021q/vlan_dev.c.org      2003-02-25 15:23:09.000000000
> > +0100
> > +++ linux-2.4/net/8021q/vlan_dev.c      2003-10-07 16:01:29.000000000 +0200
> > @@ -75,7 +75,12 @@
> > static inline struct sk_buff *vlan_check_reorder_header(struct sk_buff
> > *skb)
> > {
> >         if (VLAN_DEV_INFO(skb->dev)->flags & 1) {
> > -               skb = skb_share_check(skb, GFP_ATOMIC);
> > +               if (skb_shared(skb) || skb_cloned(skb)) {
> > +                       struct sk_buff *nskb;
> > +                       nskb = skb_copy(skb, GFP_ATOMIC);
> > +                       kfree_skb(skb);
> > +                       skb = nskb;
> > +               }

Thanks for catching that!

So, what good is skb_share_check then?
Maybe we should have a skb_share_or_cloned_check() ?

Ben


--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc  http://www.candelatech.com