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

[Ondrej Zajicek]

On Thu, May 06, 2021 at 05:09:53PM +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 ptpnumbered/unnumbered interface. 
> 1. Forp2p connections, ospf should be sending only multicast packets toallospfrouters, but I see its sending to unicast address.
> (From RFC “On physical point-to-point networks, theIP destination is always set to the address AllSPFRouters”)
> 
> 2. Forptp over unnumbered interface, bird requires peer address configuration whichis not required from the ospf perspective. Because bird is using peer addressand sending unicast packets, bird cannot form multiple ospf adj over ptpunnumbered interface between 2 endpoints using same peer address.
> Made some quick changes and have attached the patch thataddresses the issues. Relaxed the source ip address validation for ptp link inpacket.c for now. More validation can be added to make it complete.
> Thanks and Regards,Senthil

Hi

Just finished some changes based on your suggestions. You can try it:

https://gitlab.nic.cz/labs/bird/-/commit/2a0af925b83f699d126cf0e733a49c75ffd86033
(and two previous commits)

 - PtP ifaces shouls always use multicast

 - Allow OSPF PtP (or PtMP) on ifaces with just host address (/32)

The later required some more changes that were not in your patch, e.g.
using ONLINK flag for route nexthops on these unnumbered ifaces.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
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"To err is human -- to blame it on a computer is even more so."