Localisation is a major topic in the Wireless Sensor Networks and the Internet Of Things. This Work-in-Progress paper introduces ALO, an Ad-hoc Localisation Object proposed to help in designing in-stack localisation services, i.e. a service that enables the computation of mobile node positions, relying only on information from the protocol stack such as signal properties, RSSI, message timestamps, neighbour tables and routing tables. The paper presents ALO and then focuses on the implementation of a Time-Of-Flight ranging process using ALO. A suitable ranging protocol, minimizing overhead, is presented and evaluated on the LocURa4IoT testbed, using Ultra-Wide Band (UWB)-based wireless sensor nodes. The results show that the ranging accuracy is under 20cm in indoor Line of Sight conditions, using this ranging protocol included in regular traffic messages, instead of using dedicated ranging messages.