Provide Example for presharedkey implementation about wireguard-rs HOT 1 OPEN

Hi,

Here is a little insights for people that want to know how to implement it :

You can insert your preshared key inside the peer using the insert method.

Let's take the example again. In the for loop, we first create the secret then we create the Publickey from the secret, push the peer key in the vec named peer_keys, then create a peer from the public key, create an address according to the peer id and then push in the allowed_ips field of the structure peer, then configure the peer to be written on the API.

This workflow does not include the preshared_keys yet. To do so, you must bear in mind that the preshared_keys are a type Key (same type as the key used to create the peer)

To create the key simply do :

let peer_psk_secret = StaticSecret::random();
let peer_u8_psk: [u8; 32] = peer_psk_secret.to_bytes().as_ref().try_into().expect(could not convert static secret to u8)
let peer_psk_key: Key = peer_psk_secret.as_ref().try_into().expect("could not convert key u8 to key")
peer.preshared_keys.insert(peer_psk_key)

There might be unecessary steps for conversions but It works well for me.
Maybe @teon or @wojcik91 can add a sample of this to the server.rs example

from wireguard-rs.