feat: Add vars.networking, advertise routes on tailscale for servers

nix/nixos/modules/tailscale/default.nix

···
       default = false;
       type = lib.types.bool;
     };
+    advertise.routes = lib.mkOption {
+      description = "routes to advertise";
+      default = [];
+      type = with lib.types; listOf str;
+    };
     advertise.tags = lib.mkOption {
       description = "ACL tags to advertise";
       default = ["nixos"];
···
       inherit (cfg) authKeyParameters;
       enable = true;
       authKeyFile = config.my.secrets."tailscale-oauth-secret".path;
+      disableUpstreamLogging = true;
       extraUpFlags =
         [
           "--accept-dns"
···
         ]
         ++ lib.optionals cfg.advertise.exitNode [
           "--advertise-exit-node"
+        ]
+        ++ lib.optionals (cfg.advertise.routes != []) [
+          "--advertise-routes=${lib.concatStringsSep "," cfg.advertise.routes}"
         ]
         ++ lib.optionals (tags != []) [
           "--advertise-tags=${formattedTags}"

nix/nixos/profiles/server.nix

···
 {
   config,
   lib,
+  self,
   ...
 }: let
+  inherit (self.vars.networks.home) routingPrefix;
   cfg = config.my.profiles.server;
 in {
   options.my.profiles.server = lib.mkEnableOption "server profile";
   config = lib.mkIf cfg {
     my = {
-      networking.tailscale.enable = true;
-      networking.tailscale.trusted = true;
+      networking.tailscale = {
+        enable = true;
+        trusted = true;
+        advertise.exitNode = true;
+        advertise.routes = [routingPrefix];
+      };
     };
 
     documentation.man.cache.enable = false;

vars/default.nix

···
   name.full = "Luna Perroni";
   email.main = "[e-mail]";
   flake.path = "~/.config/nixos";
+  networks = import ./networks.nix;
   repo = rec {
     main = github;
     github = "https://github.com/lpchaim/nixos";

vars/networks.nix

···
+{
+  home = {
+    gateway = "10.0.0.1";
+    routingPrefix = "10.0.0.0/8";
+    subnetMask = "255.255.255.0";
+  };
+}