bird adversites a direct route from an interface without carrier

[Alarig Le Lay]

Hello Ondrej,

On Mon 18 Oct 2021 17:39:44 GMT, Ondrej Zajicek wrote:
> On Mon, Oct 11, 2021 at 01:20:52PM +0200, Alarig Le Lay wrote:
> > Hi,
> > 
> > On one router I have an interface that used to be connected to another
> > machine, so the state is NO-CARRIER:
> > core01-arendal ~ # ip addr show enp1s0
> > 2: enp1s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
> >     link/ether 00:0d:b9:48:c1:c0 brd ff:ff:ff:ff:ff:ff
> >     inet 10.0.4.1/31 scope global enp1s0
> >        valid_lft forever preferred_lft forever
> >     inet6 2001:4640:a14f:fffd::2/127 scope global
> >        valid_lft forever preferred_lft forever
> >     inet6 fe80::20d:b9ff:fe48:c1c0/64 scope link
> >        valid_lft forever preferred_lft forever
> 
> Hi
> 
> What do you see in 'show interfaces' 'show ospf interface' and
> 'show ospf state' on given router? Is it Linux or BSD?

The router is a Linux (5.10).

And for the outputs:

bird> show interfaces
enp1s0 up (index=2)
	MultiAccess Broadcast Multicast AdminUp LinkDown MTU=1500
	10.0.4.1/31 (Preferred, opposite 10.0.4.0, scope site)
	fe80::20d:b9ff:fe48:c1c0/64 (Preferred, scope link)
	2001:4640:a14f:fffd::2/127 (Preferred, opposite 2001:4640:a14f:fffd::3, scope univ)
bird> show ospf interface "enp1s0"
ospf_ipv4:
Interface enp1s0 (10.0.4.0/31)
	Type: ptp
	Area: 4.8.8.4 (67635204)
	State: Loopback
	Priority: 1
	Cost: 1
	ECMP weight: 1
	Hello timer: 10
	Wait timer: 40
	Dead timer: 40
	Retransmit timer: 5

ospf_ipv6:
Interface enp1s0 (IID 0)
	Type: broadcast
	Area: 4.8.8.4 (67635204)
	State: Loopback
	Priority: 1
	Cost: 1
	ECMP weight: 1
	Hello timer: 10
	Wait timer: 40
	Dead timer: 40
	Retransmit timer: 5
	Designated router (ID): 45.91.126.254
	Designated router (IP): fe80::20d:b9ff:fe48:c1c0
	Backup designated router (ID): 0.0.0.0
	Backup designated router (IP): ::
bird> show ospf state ospf_ipv4
area 0.0.0.0
[…]
	router 45.91.126.254
		distance 0
		external 10.0.4.0/31 metric2 10000
[…]

If you want the full output, here they are:
https://paste.swordarmor.fr/raw/zpAv

The router from which I dumped the OSPF route is connected to enp3s0.50,
which is in area 4.8.8.4, like enp1s0.
However, both routers are inside 0.0.0.0 via other interfaces.

If my OSPF configuration might help, it’s https://paste.swordarmor.fr/raw/OIkL
The files matched by "/etc/bird.lag-*.conf" are generated by cron,
adapting the cost with the latency. (so lag as time, not aggregation
here)

If you want a more detailed view of my router, don’t hesitate to ask me,
or if you need more details as well :)

Regards,
-- 
Alarig