Bug#844246: ignores Route Preference in received router advertisements

[Marc Haber]

Hi Andreas,

I appreciate the work and detail you have put into this issue and
apologize for my flawed preparation of the bug report in advance.

On Thu, Nov 17, 2016 at 04:26:30PM +0100, Andreas Henriksson wrote:
> When *not* using networkd (ie. kernel ndisc handling) the route gets set
> up with preference medium though.

You're so right. I observed the issue on my personal notebook which is
the -only- system in my environment that does -not- run
systemd-networkd for its lack of WPA support. I therefore filed this
bug report against the wrong package. Feel free to close this.

>  I looked at the kernel code and ended up at
>  http://lxr.free-electrons.com/source/net/ipv6/ndisc.c#L1238 which
>  seems to explain why as I seem to (unintentionally) have:
> 
> $ cat /proc/sys/net/ipv6/conf/eth2/accept_ra_rtr_pref 
> 0

I observed the same and put
net.ipv6.conf.enp0s25.accept_ra_rtr_pref=1
in /etc/sysctl.conf. restarting systemd-sysctl made the 1 show up in
/proc until the next reboot, when it was zero again. restarting
systemd-sysctl made the 1 show up again. I guess that systemd-sysctl
is started too early.

Having the 1 in accept_ra_rtr_pref doesn't change the route priority
though, it still gets set up with priority medium.

It might be interesting as well that accept_ra_rtr_pref has a
functional default of "enabled" if accept_ra is enabled. I do have
accept_ra set to 2.

> Is there any chance your route wasn't actually set up by systemd-networkd?

You're so right. I apologize.

Greetings
Marc

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