ospf ptp link sending unicast packets instead of multicast; peer address config not required

[Joakim Tjernlund]

On Thu, 2021-05-06 at 20:30 +0200, Joakim Tjernlund wrote:
> On Thu, 2021-05-06 at 17:09 +0000, Senthil Kumar Nagappan wrote:
> > Hi,
> > 
> > I did sent this message a week back but I could not see it in the mailing, moreover just now subscribed to this mailing list, so sending this again.
> > 
> > I’m seeing some issues with ospf adj over ptp numbered/unnumbered interface. 
> > 
> > 1. For p2p connections, ospf should be sending only multicast packets to allospfrouters, but I see its sending to unicast address.
> > (From RFC “On physical point-to-point networks, the IP destination is always set to the address AllSPFRouters”)
> 
> Agreed, I recall fixing the same for Quagga long time ago.
> 
> > 2. For ptp over unnumbered interface, bird requires peer address configuration which is not required from the ospf perspective. Because bird is using peer address and sending
> > unicast packets, bird cannot form multiple ospf adj over ptp unnumbered interface between 2 endpoints using same peer address.
> > Made some quick changes and have attached the patch that addresses the issues. Relaxed the source ip address validation for ptp link in packet.c for now. More validation can be
> > added to make it complete.
> 
> I don't quite understand what you are saying here, can you elaborate?
> 

One thing I recall, BIRD OSPF seems to always require dest IP address for its routes. For a PtoP I/F
this is optional/not needed so I guess this is a bug in BIRD. Possibly because of bug 1)

 Jocke