Re: default route problem

[Dan Williams <dcbw redhat com>]

On Thu, 2008-11-13 at 16:19 +0000, Roy Marples wrote:
> Dan Williams wrote:
> > There's also an open bug where NM should be adding a host route to the
> > gateway when it's out of the current subnet.  I have a patch for that,
> > but there were some netlink issues that prevented me from finishing it.
> > 
> > Routing is a bit tricky here because netlink thinks you cannot add the
> > route to the gateway out of the subnet until you add a default route via
> > 0.0.0.0 first, then add the gateway host route, then replace the default
> > route with one via the gateway.
> > 
> > This isn't purely a netlink problem, since you can see the same issues
> > with /sbin/ip.
> 
> Could you point me to that bug? I would like to ensure that dhcpcd works 
> with the same criteria. I'm pretty sure it does, but only for CIDR routes.
> But from the sounds of it, you could just construct the netlink message 
> to say the host is directly on the link instead.

Could you explain that idea a bit more?  I tried various methods with
libnl to do this inside NM, but I don't fully understand the kernel
routing table behavior in this situation.  The procedure for
using /sbin/ip and libnl will be essentially the same, so if we can come
up with a procedure that works in /sbin/ip it should be easy to convert
to libnl.  Really, you just need to do something like:

ifconfig eth0 192.168.1.30/32 up
/sbin/ip route add default dev eth0 via 192.168.1.1

Dan