Introduce Wireguard support to bird

[Toke Høiland-Jørgensen]

Ondrej Zajicek <santiago at crfreenet.org> writes:

> On Fri, Jun 07, 2019 at 06:21:42PM +0000, Janne Heß wrote:
>> Hey everyone,
>> 
>> as advertised, I have completed the Wireguard support.
>> You might see that I am not really a C expert, but I hope the code is good enough.
>> If you need me to change anything or have additional questions, just let me know.
>
> Hi
>
> Could you explain what the Wireguard support broadly does (compared to
> regular route update)?

Wireguard ties prefixes to public keys to figure out which peer to send
a packet to. This supersedes any regular routing on that interface, so
it needs to be done in addition to installing the route on the
interface. See https://www.wireguard.com/#cryptokey-routing

-Toke