clanServices/wireguard: add networking exports to controllers

Part of https://git.clan.lol/clan/clan-core/issues/5549

clanServices/wireguard/default.nix

@@ -56,6 +56,8 @@
 
 {
   clanLib,
+  lib,
+  directory,
   ...
 }:
 let
@@ -298,6 +300,18 @@ in
         ...
       }:
       {
+        exports.networking = {
+          peers = lib.mapAttrs (name: _machine: {
+            host.plain =
+              clanLib.vars.getPublicValue {
+                flake = directory;
+                machine = name;
+                generator = "wireguard-network-${instanceName}";
+                file = "prefix";
+              }
+              + "::1";
+          }) roles.controller.machines;
+        };
 
         # Controllers connect to all peers and other controllers
         nixosModule =