OSPF HELLO wrong mask

[Alexander V. Chernikov]

On 18.05.2013 16:43, Ondrej Zajicek wrote:
> On Wed, May 15, 2013 at 09:18:10PM +0400, Slawa Olhovchenkov wrote:
>>> So this is a problem with multiple IPs on an iface. On BSD, we support
>>> just one primary address in OSPF (others are just handled as stubs).
>>> Lexicographically smallest address was chosen. Unfortunately the kernel
>>> chose a different one as a source address.
>> Why lexicographically smallest?
>> Why not first from getifaddrs() list?
> Well, this is mainly a consequence of the facts that primary address
> selection is currently in platform independent code and on Linux
> the order of addressess has no real meaning. Therefore it seemed
> to be a good idea to make it more deterministic, i.e. independent
> on the order in which the addresses appeared.
>
> Perhaps the best idea would be to remove the whole primary address
> selection (as it does more harm than good) and replace it by platform
> dependent flag that this address is preferred for the interface
> (and don't even use this flag on Linux).
>
> We enumerate addresses on BSD using CTL_NET / NET_RT_IFLIST sysctl scan.
> Does anyone know whether is a reliable way to determine which one of
> returned addresses is the primary one or whether we should just add an
It should be the first one, yes. The problem starts when the primary 
address gets removed.
I'm thinking of adding special flag to ifa_flags indicating that address 
is primary, and either
use RTM_NEWADDR to announce new primary address (sent before 
RTM_DELADDR) or completely
new message like RTM_PRIMADDR with the same data.

However, I probably can do this for FreeBSD only, and something has to 
be implemented for
other *BSD flavors..
> another call of SIOCGIFADDR (as suggested by Alexander V. Chernikov)?
It seems that platform-dependent code with addional constantly open 
socket calling SIOCGIFADDR on address change is the easiest hack^Wthing 
to do..
> I would guess it is the first one, but i am not sure if that is specified
> or just a coincidence.
>