VRF support in unbound?

[Ralf Jung]

Hi all,

I am playing around with the [VRF] support on the Linux kernel, and got basic
routing and address assignment to work for IPv4 and IPv6.  The next step,
obviously, is to get DNS, and here I am running into the following error in unbound:

> unbound[3115]: [3115:0] error: can't bind socket: Cannot assign requested address for 2a03:2260:3009::2

This is the expected error when an application does not use setsockopt for
SO_BINDTODEVICE to configure the device on which the address is to be bound.

Is there any way to tell unbound to bind to a particular device (and not just a
particular address)?  The only options I found for configuring unbound allow
giving IP addresses to bind to, but there seems to be no way to also configure
the network device to use.

[VRF]: https://www.kernel.org/doc/Documentation/networking/vrf.txt

Kind regards,
Ralf