refactor

modules/nixos/services/tailscale/default.nix

@@ -0,0 +1,69 @@
+{ lib, pkgs, config, ... }:
+
+with lib;
+with lib.plusultra;
+let cfg = config.plusultra.services.tailscale;
+in
+{
+  options.plusultra.services.tailscale = with types; {
+    enable = mkBoolOpt false "Whether or not to configure Tailscale";
+    autoconnect = {
+      enable = mkBoolOpt false "Whether or not to enable automatic connection to Tailscale";
+      key = mkOpt str "" "The authentication key to use";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = cfg.autoconnect.enable -> cfg.autoconnect.key != "";
+        message = "plusultra.services.tailscale.autoconnect.key must be set";
+      }
+    ];
+
+    environment.systemPackages = with pkgs; [ tailscale ];
+
+    services.tailscale = enabled;
+
+    networking = {
+      firewall = {
+        trustedInterfaces = [ config.services.tailscale.interfaceName ];
+
+        allowedUDPPorts = [ config.services.tailscale.port ];
+
+        # Strict reverse path filtering breaks Tailscale exit node use and some subnet routing setups.
+        checkReversePath = "loose";
+      };
+
+      networkmanager.unmanaged = [ "tailscale0" ];
+    };
+
+    systemd.services.tailscale-autoconnect = mkIf cfg.autoconnect.enable {
+      description = "Automatic connection to Tailscale";
+
+      # Make sure tailscale is running before trying to connect to tailscale
+      after = [ "network-pre.target" "tailscale.service" ];
+      wants = [ "network-pre.target" "tailscale.service" ];
+      wantedBy = [ "multi-user.target" ];
+
+      # Set this service as a oneshot job
+      serviceConfig.Type = "oneshot";
+
+      # Have the job run this shell script
+      script = with pkgs; ''
+        # Wait for tailscaled to settle
+        sleep 2
+
+        # Check if we are already authenticated to tailscale
+        status="$(${tailscale}/bin/tailscale status -json | ${jq}/bin/jq -r .BackendState)"
+        if [ $status = "Running" ]; then # if so, then do nothing
+          exit 0
+        fi
+
+        # Otherwise authenticate with tailscale
+        ${tailscale}/bin/tailscale up -authkey "${cfg.autoconnect.key}"
+      '';
+
+    };
+  };
+}