The general idea is a VPN connection from each laptop to a central Linux server, where all the VPN connections are connected to a Linux bridge. When the interfaces on each laptop are configured, the laptops can talk to each other.
There are several layers of things to build over that basic idea.
Since this must be a secure connection, we use TLS for encryption. Also, access is controlled by a client certificate used on each laptop to initiate the VPN connection to the server. This means that the VPN server will act as a certificate authority.
