Tailscale setup

networking/vpn-host.nix

@@ -0,0 +1,32 @@
+{ config, lib, pkgs, ... }: {
+  environment.systemPackages = [ pkgs.tailscale ];
+
+  services.tailscale.enable = true;
+
+  systemd.services.tailscale-autoconnect = {
+    description = "Automatic oneshot connection to tailscale";
+
+    after = [ "network-pre.target" "tailscale.service" ];
+    wants = [ "network-pre.target" "tailscale.service" ];
+    wantedBy = [ "multi-user.target" ];
+
+    serviceConfig.Type = "oneshot";
+
+    script = with pkgs; ''
+      sleep 2
+
+      status="$(${tailscale}/bin/tailscale status -json | ${jq}/bin/jq -r .BackendState)"
+      if [ $status = "Running" ]; then # if so, then do nothing
+        exit 0
+      fi
+
+      ${tailscale}/bin/tailscale up -authkey ${config.age.secrets.tailscale.path}
+    '';
+  };
+
+  networking.firewall = {
+    trustedInterfaces = [ "tailscale0" ];
+    allowedUDPPorts = [ config.services.tailscale.port ];
+    allowedTCPPorts = [ 22 ];
+  };
+}