Re: [B.A.T.M.A.N.] [PATCHv4 5/7] batman-adv: Distributed ARP Table - add snooping functions for ARP messages

Antonio Quartulli
2011-11-25T11:17:08Z

On Fri, Nov 25, 2011 at 09:45:56AM +0100, Andrew Lunn wrote:
> Hi Antonio
>
> General question. In the Linux ARP decode code is:
>
> /*
> * Check for bad requests for 127.x.x.x and requests for multicast
> * addresses. If this is one such, delete it.
> */
> if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
> goto out;
>
> I don't see the same filtering here. What would happen if you did
> receiver and cached such a bad request?

atually there isnot such control over the arp message content. In case
of, let's say, a malicious ARP message of this type, it is stored like
any other one.

>
> In a similar direction, how does duplicate address detection work?
> i.e. i ARP my own address to see if somebody else is using it?
>
> Or do i just need to RTFM your GSOC documentation :-)
>

Don't think so. Actually I/we didn't think too much about this kind of
cases. Well, a duplicate entry is simply overwritten: I mean, if we
already have the entry [IPa,MACa] in the table, any other ARP reply containing
[IPa,MACb] will update the older one and MACa will be lost.

Do you expect a different behaviour? Can I do it better?

Cheers,

--
Antonio Quartulli

..each of us alone is worth nothing..
Ernesto "Che" Guevara ☭