Document API of wireguard broker

[aparcar]

I'm using an additional source of key material which I'm combining via a KDF with the Rosenpass output. Ideally the KDF output would be fed into Wireguard from an unprivileged script, which could be possible using the Rosenpass wireguard broker.

For that I'd like to ask for further details on the broker API. Is it possible to set the PSK for a peer via the socket if using something else than Rosenpass directly?

A second approach would be to feed the extra key material into Rosenpass itself, but from my understanding it's preferred to use a KDF instead of feeding key material into Rosenpass directly. If this is no longer valid please correct me @koraa