Re: ospf on wg(4)

On 29/01/2021 23:32, Bastien Durel wrote:
> Le 29/01/2021 à 17:44, Olivier Cherrier a écrit :
>>     Hi,
>>
>> I'm trying to setup OSPF on a working Wireguard VPN using 6.8 amd64
>> machines. This is what I get:
>>
>> # ospfd -dvvv
>> id = "172.26.1.1"
>> startup
>> kr_init: priority filter enabled
>> orig_rtr_lsa: area 0.0.0.0
>> orig_rtr_lsa: stub net, interface wg0
>> if_fsm: event UP resulted in action START and changing state for
>> interface wg0 from DOWN to P2P
>> send_packet: error sending packet to 224.0.0.5 on interface wg0: Network
>> is unreachable
>> send_hello: Network is unreachable
>> [...]
>>
>>
>>
>> # ifconfig wg0
>> wg0: flags=80c3<UP,BROADCAST,RUNNING,NOARP,MULTICAST> mtu 1420
>>     index 23 priority 0 llprio 3
>>     wgport 33222
>>     wgpubkey XXX
>>     wgpeer YYY
>>         wgpka 23 (sec)
>>         wgendpoint A.B.C.D 31502
>>         tx: 4317366604, rx: 382870060
>>         last handshake: 47 seconds ago
>>         wgaip 192.168.1.0/24
>>         wgaip 172.26.1.3/32
>>     wgpeer WWW
>>         wgpka 23 (sec)
>>         wgendpoint E.F.G.H 15776
>>         tx: 609183380, rx: 1523684
>>         last handshake: 1 seconds ago
>>         wgaip 172.26.0.0/24
>>         wgaip 172.26.1.2/32
>>     groups: wg
>>     inet 172.26.1.1 netmask 0xffffff00 broadcast 172.26.1.255
>>
>>
>> Is it possible to use a wg(4) interface for ospfd(8)?
>>
>> Thank you,
>> Best.
>>
> Hello.
>
> It is possible, I use it myself. You have to allow multicast address
> on wg(4) interface(s):
> 225.0.0.5 for all OSPF routers
> 224.0.0.6 for all DR/BDR
>
> (I use wgaip 0.0.0.0/0, so my config is not relavant for you)
>
> Regards,
>
Sorry to jump in, but does this also add routes for 225.0.0.{5,6} via wg0?

If this is a case, this would be a problem for multiple interfaces.

Or maybe wg(4) handles multicast differently than normal IP

thanks

G