flake/modules/services/wgautomesh.nix

{
  config,
  pkgs,
  lib,
  cfg,
  ...
}: let
  prefix = "lyn";

  # function to make a peerlist suitable for wgautomesh
  buildPeerlist = version: hosts: let
    #filter out hosts that have wg.enabled set to false
    wgEnabledHosts = lib.filterAttrs (_: host: host.wg.enabled or false) hosts;
    #filter out hosts that don't support IP{$version}
    filteredHosts = lib.filterAttrs (_: host: host.${version}.public != "") wgEnabledHosts;
  in
    lib.mapAttrs (name: host: {
      pubkey = host.wg.pubkey;
      #if there is no public IP, make endpoint null so wgautomesh knows it unknown
      endpoint = host.${version}.public;
      address = host.${version}.internal;
    })
    filteredHosts;

  # helper vars to prettify
  meshnetwork = config.${prefix}.network;
  currentHost = meshnetwork.hosts.${config.networking.hostName};
  wireguardPort = currentHost.wg.port;
in {
  opt.useIPv6 = lib.mkOption {
    type = lib.types.bool;
    description = "Whether to use IPv6. Defaults to true";
    default = true;
  };
  config = {
    networking.wireguard.interfaces.wg0 = {
      ips =
        if cfg.useIPv6
        then ["${meshnetwork.wg_subnets.IPv6}"]
        else ["${meshnetwork.wg_subnets.IPv4}"];
      listenPort = wireguardPort;
      privateKeyFile = "/var/lib/wireguard-keys/private";
      mtu = 1420;
    };
    services.wgautomesh = {
      enable = true;
      settings = {
        interface = "wg0";
        peers =
          if cfg.useIPv6
          then buildPeerlist "v6" meshnetwork.hosts
          else buildPeerlist "v4" meshnetwork.hosts;
        upnp_forward_external_port = wireguardPort;
      };
    };
  };
}