Hello Ilham,

Looks like this is not a same bug. There should be a missing condition in next-hop resolving.

Which router produces these warning?

How it connects to 1.2.3.4/5.6.7.8/9.1.2.3, by WireGuard?

What are interface types of those connections? (`show ospf interface ospfv3v6` will tell)

Regards,

Soha

From: Ilham Maulana <ilhamsupernatural@gmail.com>
Sent: Monday, March 11, 2024 5:02 PM
To: Soha Jin <soha@jin.sh>
Cc: Soha Jin via Bird-users <bird-users@network.cz>
Subject: RE: BIRD 2.15

Hello Soha,

Thank you. It works with 'ecmp off'.

One more thing I notice in Bird 2.15, is this warning message.

---

Kernel dropped some netlink messages, will resync on next scan.

ospfv3v6: Unexpected case in next hop calculation

ospfv3v6: Cannot find next hop for LSA (Type: 2001, Id: 0.0.0.0, Rt: 1.2.3.4)

ospfv3v6: Unexpected case in next hop calculation

ospfv3v6: Cannot find next hop for LSA (Type: 2001, Id: 0.0.0.0, Rt: 5.6.7.8)

ospfv3v6: Unexpected case in next hop calculation

ospfv3v6: Cannot find next hop for LSA (Type: 2001, Id: 0.0.0.0, Rt: 9.1.2.3)

--

Here's the simple topology.

Router A - Router B - Router C.

Router B got LSA information from from A and C, and install it in B' routing table.. and( I guess) forward it to its adjacent neighbor.

Router C does not install the LSA Information of Router A in OSPF Database and vice versa.

Thanks.

On 11/03/2024 14:19:57, Soha Jin <soha@jin.sh> wrote:

Hello Ilham,

You can disable ECMP with `ecmp off;` in the protocol `ospfv3v6` as a workaround (if you don’t need ECMP).

Since 31aa62ae6d2e111e87c08b4b27a16ead968f0689, OSPFv3 will use direct route for pointopoint interfaces. Unfortunately, kernel doesn’t support multipath with a device only route, so there is a ! on the route.

BIRD v2.15 ready.
bird> show route
Table master4:
192.88.99.0/24 unicast [ospf2 14:55:01.553] * I (150/20) [1.9.1.9]
dev wg-main
dev wg-main2

Table master6:
2001:db8:272::/48 unicast [ospf1 14:55:01.553] ! I (150/20) [1.9.1.9]
dev wg-main
dev wg-main2

I am drafting a patch to fix it.

Regards,
Soha

----------------------------------------------
From: Bird-users On Behalf Of Ilham Maulana
Sent: Monday, March 11, 2024 12:27 PM
To: Ondrej Filip ; Ondrej Zajicek via Bird-users
Subject: Re: BIRD 2.15

Hello,

After upgrading to 2.15, OSPFv3 is broken. Previously working on 2.14. No configuration changes.

This capture taken from router with Bird 2.15 installed.

--------------------------------
OSPF route from router with Bird 2.15. it has ! sign.

birdc show route all 2a05:abcd:abcd:abcd::/128
BIRD 2.15 ready.
Table master6:
2a05:abcd:abcd:abcd::/128 unicast [ospfv3v6 2024-03-11 10:05:40] ! I (150/10) [1.1.1.1]
dev wg6
dev wg7
Type: OSPF univ
OSPF.metric1: 10
OSPF.router_id: 1.1.1.1


-----------------------------------------------------
OSPF route from router with Bird 2.14, working as expected, with * sign.

birdc show route all 2a05:abcd:abcd:abcd::3/128
BIRD 2.15 ready.
Table master6:
2a05:abcd:abcd:abcd::3/128 unicast [ospfv3v6 2024-03-11 08:23:55] * I (150/10) [192.168.99.141]
dev wg2
Type: OSPF univ
OSPF.metric1: 10
OSPF.router_id: 192.168.99.141

Any idea, what's going on?