Re: [B.A.T.M.A.N.] [PATCH 2/2] batman-adv: filter out invalid DAT entries

[Matthias Schiffer <mschiffer@universe-factory.net>]

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On 01/23/2013 10:39 PM, Matthias Schiffer wrote:
> ipv4_is_zeronet() checks if the first byte of the address is zero, to my
> knowledge there is no special funtion for checking for the unspecified
> address, as the case is trivial and independent of byte ordering.
> 
> It might make sense though to check for different types of addresses
> that are invalid for ARP (zeronet, loopback, multicast, etc.), but I
> wanted to keep the patch as simple as possible. If you think these
> should be filtered as well, I'll prepare a v2.
> 
> Matthias

Oh, I shouldn't top post. Well, continuing here now...

I just noticed that batadv_arp_get_type() already checks for loopback
and multicast addresses, so adding ipv4_is_zeronet() should be enough.
I'd keep that in batadv_dat_entry_add() though as the source of ARP
replies with 0.0.0.0 destination is still valid and can be should to the
DAT.

Matthias


> 
> 
> On 01/23/2013 10:07 PM, Antonio Quartulli wrote:
>> On Wed, Jan 23, 2013 at 06:11:54 +0100, Matthias Schiffer wrote:
>>> Due to duplicate address detection and other strange ARP packets, sometimes
>>> entries with broadcast MAC addresses or unspecified IP addresses would get into
>>> the Distributed ARP Table. This patch prevents these and some other kinds of
>>> invalid entries from getting into the DAT.
>>>
>>> Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
>>> ---
>>>  distributed-arp-table.c | 12 ++++++++++++
>>>  1 file changed, 12 insertions(+)
>>>
>>> diff --git a/distributed-arp-table.c b/distributed-arp-table.c
>>> index 9f4cff3..e28be57 100644
>>> --- a/distributed-arp-table.c
>>> +++ b/distributed-arp-table.c
>>> @@ -274,6 +274,18 @@ static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip,
>>>  	struct batadv_dat_entry *dat_entry;
>>>  	int hash_added;
>>>  
>>> +	/* filter invalid MAC addresses that are sometimes used as
>>> +	 * destinations of ARP replies
>>> +	 */
>>> +	if (is_zero_ether_addr(mac_addr) || is_multicast_ether_addr(mac_addr))
>>> +		return;
>>> +
>>> +	/* ARP requests with unspecified source address are used for
>>> +	 * duplicate address detection, we don't want those in the DAT either
>>> +	 */
>>> +	if (!ip)
>>
>> Hi Matthias,
>> what about using ipv4_is_zeronet() ? Even if this is a base case, I would rather
>> prefer to use an already implemented function.
>>
>> Cheers,
>>
> 
> 



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