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Networking setup

Note: these steps are required only when firmware is run on PC. They shouldn't be done for hardware Fobnail Token.

To run Fobnail firmware directly on your PC a special network interface to communicate with the external world is needed. You can create such an interface by executing the following commands:

sudo ip tuntap add fobnail0 mode tap user `whoami`

sudo ip addr add 169.254.0.8/16 dev fobnail0

sudo ip link set dev fobnail0 up

To make this persistent across reboots, you can use systemd-networkd, which ships with most distributions. To make the interface persistent, follow these steps:

  • Create /etc/systemd/network/fobnail0.netdev.
[NetDev]
Name=fobnail0
Kind=tap

[Tap]
User=put your user name here
  • Create /etc/systemd/network/fobnail0.network.
[Match]
Name=fobnail0

[Network]
Address=169.254.0.8/16
DHCPServer=false
  • Enable systemd-networkd.
sudo systemctl enable --now systemd-networkd

You should see a new network interface created.

ip addr show dev fobnail0

40: fobnail0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
    link/ether 8e:36:f4:4c:98:28 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::8c36:f4ff:fe4c:9828/64 scope link
       valid_lft forever preferred_lft forever

You should see the same interface inside Docker container.

run-fobnail-sdk.sh /bin/bash

Inside docker container:

ip link show fobnail0

40: fobnail0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN mode DEFAULT group default qlen 1000
    link/ether 8e:36:f4:4c:98:28 brd ff:ff:ff:ff:ff:ff

Note: TAP interface passthrough may not work if your distro is using SELinux. If you can't see the network interface in Docker, try turning SELinux into permissive mode. 

$ sudo setenforce 0

If you are using WSL (Windows Subsystem for Linux) with Docker Desktop, interface passthrough won't work because Docker is located on a separate Virtual Machine. In that case, you can still use Fobnail SDK to build the firmware, but the firmware must be run from outside the container.