Re: [B.A.T.M.A.N.] Antwort: Re: [PATCHv3 2/6] batman-adv: speed up dat by snooping received ip traffic

[Antonio Quartulli <a@unstable.cc>]

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On Fri, May 20, 2016 at 01:32:35PM +0200, Andreas Pape wrote:
> "B.A.T.M.A.N" <b.a.t.m.a.n-bounces@lists.open-mesh.org> schrieb am
> 19.05.2016 21:45:53:
> 
> > Von: Linus Lüssing <linus.luessing@c0d3.blue>
> > An: The list for a Better Approach To Mobile Ad-hoc Networking
> > <b.a.t.m.a.n@lists.open-mesh.org>
> > Datum: 19.05.2016 21:47
> > Betreff: Re: [B.A.T.M.A.N.] [PATCHv3 2/6] batman-adv: speed up dat
> > by snooping received ip traffic
> > Gesendet von: "B.A.T.M.A.N" <b.a.t.m.a.n-bounces@lists.open-mesh.org>
> >
> > On Fri, May 06, 2016 at 10:58:23AM +0200, Andreas Pape wrote:
> > > +void batadv_dat_entry_check(struct batadv_priv *bat_priv, struct
> > sk_buff *skb,
> > > +             unsigned short vid)
> > > +{
> > [...]
> > > +   if (iphdr) {
> > > +      batadv_dbg(BATADV_DBG_DAT, bat_priv,
> > > +            "Snooped IP address: %pI4 %pM (vid: %d)\n",
> > > +            &iphdr->saddr, ethhdr->h_source,
> > > +            BATADV_PRINT_VID(vid));
> > > +      batadv_dat_entry_add(bat_priv, iphdr->saddr,
> > > +                 ethhdr->h_source, vid);
> > > +   }
> >
> > Not sure whether it is necessary, or whether there is a check
> > somewhere later within DAT. But should we exclude some
> > iphdr->saddr or ethhdr->h_source addresses? For instance a
> > DHCPDISCOVER usually has a zero-ip address.
> 
> I think you have a good point here. Excluding especially
> ip addresses like zero-ip address seems reasonable. Although
> I think that this isn't a problem as long as no one is sending
> arp requests for such ip addresses, filling the dat table with
> unreasonable entries isn't a smart idea either. I will add some
> additional tests here for reasonable ip addresses for the next
> version of the patchset.

We already have some checks in the snooping functions that are performed when
calling batadv_arp_get_type(). Aren't those enough ?

Cheers,


-- 
Antonio Quartulli

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