Bird 2 OSPF Authentication Type unknown (256) issue

[James Swineson]

Hi,

I have a Linux server and a Cisco IOS XE device connected with GRE/IPSec and then can ping each other. Today I installed Bird 2.0.5 on the Linux server and enabled OSPFv2 on both of them. Although they receive HELLO packets from each other, they refuse to establish a connection. A packet capture shows Bird is sending packets with auth type = 256 which is not something I would expect everyday:

05:38:06.129722 IP (tos 0xc0, ttl 1, id 48901, offset 0, flags [none], proto OSPF (89), length 64)
    192.168.1.2 > ospf-all.mcast.net: OSPFv2, Hello, length 44
        Router-ID 192.168.1.2, Backbone Area, Authentication Type: unknown (256)

As a test I changed authentication type from none to simple; this time Bird gave me 257:

05:40:36.129411 IP (tos 0xc0, ttl 1, id 3669, offset 0, flags [none], proto OSPF (89), length 64)
    192.168.1.2 > ospf-all.mcast.net: OSPFv2, Hello, length 44
        Router-ID 192.168.1.2, Backbone Area, Authentication Type: unknown (257)

Is there something wrong with my config or there is a bug in Bird2? Is there any workaround I can use right now?

I've already checked on both sides their interface type is set to ptp and all timers match. 

My environment:
 * Cisco IOS XE 16.9.3, CSR1000v in Hyper-V VM
 * Debian 10 in KVM, Bird 2.0.5 via official unstable repo, IPSec done with strongswan

Thanks ahead,
James Swineson