stay up wifi daemon

system-modules/stay-up.nix

@@ -0,0 +1,36 @@
+{ config, pkgs, ... }@all: with all; let
+  target = "1.1.1.1";
+  timeoutMinutes = 5;
+  logFile = "/var/log/stay-up.log";
+in {
+  systemd.services.wifi-watchdog = {
+    description = "Wi-Fi Watchdog Service";
+    after = [ "network.target" "NetworkManager.service" ];
+    wantedBy = [ "multi-user.target" ];
+    path = with pkgs; [ iputils networkmanager coreutils ];
+    script = /* bash */ ''
+      FAIL_COUNT=0
+      touch "${logFile}"
+      while true; do
+        if ping -c 1 -W 5 "${target}" > /dev/null 2>&1; then
+          FAIL_COUNT=0
+        else
+          FAIL_COUNT=$((FAIL_COUNT + 1))
+          if [ "$FAIL_COUNT" -ge "${toString timeoutMinutes}" ]; then
+            echo "$(date -Iseconds): Network unreachable for ${toString timeoutMinutes} minutes. Restarting Wi-Fi." >> "${logFile}"
+            nmcli radio wifi off
+            sleep 5
+            nmcli radio wifi on
+            FAIL_COUNT=0
+          fi
+        fi
+        sleep 60
+      done
+    '';
+    serviceConfig = {
+      Restart = "always";
+      RestartSec = "10";
+      User = "root"; # Root is required to execute nmcli radio commands and write to /var/log/
+    };
+  };
+}