bird 1.6 seems to ignore ipv6 kernel routes on 4.19

[Tom Bird]

Hi,

I recently updated some virtual machine hosting nodes to Debian Buster 
from Stretch, and I'm having an interesting problem with IPv6 kernel 
routes.  My example uses 1.6.6 but 1.6.7 shows the same behaviour, so 
I'm just wondering what I am missing.  v4 is all working as expected.

I tried a bird6.conf from a machine still running Debian Stretch, and 
that also did not import the kernel routes.

I've tried this on a test VM with bird 1.6.3 and kernel 4.9.0 and it 
imports the routes as expected.

I've set up a test VM in the lab with the following bird6.conf:

--------------------------------------
root at os-test:~# grep -v ^# /etc/bird/bird6.conf

router id 198.51.100.1;

protocol kernel {
	scan time 60;
	learn;
	device routes;
	#import none;
	import all;
}

protocol device {
	scan time 60;
}
--------------------------------------

This is just the sample file with "learn", "import all" and "device 
routes" added to the kernel protocol.

I have added a test kernel route:

root at os-test:~# route -6 add 2a03:9804::/64 gw 2a03:9802:1000:aa::1

I would expect to see this in a "show route" output from birdc6, but I 
don't.  I only see the default:

root at os-test:~# birdc6
BIRD 1.6.6 ready.
bird> show route
::/0               via 2a03:9802:1000:aa::1 on ens2 [kernel1 21:14:40] * 
(10)
bird>

If I add a protocol direct section, then I get device routes but still 
not indirect kernel routes.

Some other stuff about the system, sorry if this hasn't pasted so well.

root at os-test:~# uname -a
Linux os-test.portfast.net 4.19.0-5-amd64 #1 SMP Debian 4.19.37-5 
(2019-06-19) x86_64 GNU/Linux
root at os-test:~# netstat -rn6
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref 
Use If
::1/128                        ::                         U    256 2 
0 lo
2a03:9802:1000:aa::/64         ::                         U    256 3 
0 ens2
2a03:9804::/64                 2a03:9802:1000:aa::1       UG   1   1 
0 ens2
fe80::/64                      ::                         U    256 1 
0 ens2
::/0                           2a03:9802:1000:aa::1       UGH  1024 2 
  0 ens2
::1/128                        ::                         Un   0   4 
0 lo
2a03:9802:1000:aa::2/128       ::                         Un   0   3 
0 ens2
fe80::5054:ff:fe10:d040/128    ::                         Un   0   3 
0 ens2
ff00::/8                       ::                         U    256 2 
0 ens2
::/0                           ::                         !n   -1  1 
0 lo

Thanks,
-- 
Tom Bird

http://www.portfast.co.uk/ : AS8916
UK Limited company #6061075 : +44 1777 29 28 27