Requirements: Router Card with Wi Fi (XAP RW 001)

The Xaptum Router Card with Wi-Fi (xap-rw-001) (aka "target") will support several modes of operation.

The router card is a single-board computer that plugs into a host device (a PC running Linux) via a Mini PCI-e interface. The USB data lines of the Mini PCI-e interface are used for communication.

Overall Goal

Recall that the ENF operates much like a traditional VPN; connections to the ENF are TLS tunnels carrying the IPv6 packets.

The enftun client is a software application that runs on the host. It has two primary functions.

1. Manage the TLS tunnel to the ENF
2. Expose a virtual network interface enf0 to enable the host to route traffic through this tunnel to the ENF.

The main goal of the router card is to provide this same behavior, but as plug-n-play hardware, rather than a software client that must be installed and configured.

Requirements

1. The router card must be exposed on the host as a network interface called enf0.

2. The IP address of the host enf0 interface must be the IPv6 address assigned to this device by the ENF.

3. The internal operation must not require the use of any other IP addresses in the ENF subnet.

4. The internal operation must be compatible with any IP addressing schemes used on a other other local network that the host or router card is attached to.

5. The enf0 created by the router card should be operationally indistinguishable from the enf0 created by the enftun client. Here operationally indistinguishable means that the functional behavior observed by the host for any traffic pattern is identical between between the enftun and router card implementations.

   For example, the enftun does not interpret or modify the IPv6 traffic. So, the router card should not respond to pings or decrement TTL field of the packets. Such behavior would distinguish the card from the enftun software.

   As another example, the host enf0 interface should not be an ethernet interface. The ENF is an IP (layer 3) overlay network, not an ethernet (layer 2) network. MAC addresses, ARP, and neighbor discovery are not used on the ENF. Such behavior would distinguish the router card from the enftun software.

Pass through Mode

In this mode, the router card behaves like a standard Wi-Fi card.

(TODO: specific requirements)

Secure Mode with Host-Configured Wi-Fi

In this mode, the router card is configured like a standard Wi-Fi card, but presents the ENF network to the host, not the local network behind the access point.

(TODO: specific requirements)

Secure Mode with Pre-configured Wi-Fi

In this mode, the router card automatically connects to a pre-configured access point, and presents the ENF network to the host, not the local network behind the access point.

(TODO: specific requirements)