In the upcoming 5G network infrastructure the virtualization of network function is a key component to meet the flexibility and scalability requirements imposed by the wide range of supported applications. The Mobile Gateway is the component of the 5G core network responsible of interconnectin the mobile user equipment located in the Radio Access Network to one or more Packet Data Networks (e.g. the Internet). This work studies advantages and challenges of using eBPF (Extended Berkeley Packet Filter), a novel technolgy that allows fast packet processing in the Linux kernel, to implement such a network function. A modular prototype, providing a subset of the functionalities of the Gateway, is proposed, and its performance are compared to equivalenet network functions based on alternative data plane technologies.