Start mobile data if not available

For some reason, mobile data drops and must be restarted manually. From
own experience, it seems to occur frequently during phone calls.

modem-restart

@@ -9,6 +9,15 @@ is_modem_available()
 	return 0
 }
 
+is_data_available()
+{
+	if ! nmcli c show --active | grep -e internet -e gsm > /dev/null; then
+		return 1
+	fi
+
+	return 0
+}
+
 TRY=0
 while :; do
 	if ! is_modem_available ; then
@@ -19,6 +28,10 @@ while :; do
 	elif [ $TRY -ne 0 ]; then
 		echo $(date): Modem restarted successfully
 		TRY=0
+	elif ! is_data_available; then
+		echo $(date): Restarting mobile data
+		nmcli c up internet
+		systemd-inhibit --what=sleep --why="Restart mobile data" sleep 5
 	fi
 
 	sleep 30