When the POSBox boots without a network cable attached it will
automatically launch a wireless AP that people can connect to. This
allows them to configure what wireless network the POSBox should connect
to.
This wireless AP was configured to use the 10.10.0.0/24 subnet. The AP
itself was on 10.10.0.1. Although this is fine if used as intended it is
a quick way to take down an existing network if you where to plug in an
ethernet cable after the wireless AP has started. 10.10.0.1 is commonly
used by routers all over the world and plugging in a booted POSBox into
their networks will cause serious issues because the POSBox will share
the same IP as the router.
This moves the POSBox AP to the 10.11.12.0/24 subnet, with the AP on
10.11.12.1.
This also makes the DHCP server listen only on wlan0 because otherwise
you can end up with two DHCP servers on the same network which would
still break stuff.
The main reason for doing this is supporting the new Raspberry Pi 3. No
functional changes where made.
For Raspbian Wheezy we used to download the full image and strip it as
best we could to obtain a reasonable image size for people to
download. Since Raspbian Jessie the Raspberry Pi Foundation has started
releasing an official minimal image (Raspbian Jessie Lite) which we will
use from now on to build our image. One downside of this is that the
minimal image is a 1.3 GiB image which is too small for our
purposes so it has to be resized.
Because Raspbian Jessie migrated to systemd we cannot rely on
/etc/init.d/rcS to set up the ramdisks anymore. Jessie provides a
compatibility layer so old SysVinit scripts still work but rcS does not
block like it does in a SysVinit system, it is run in parallel with
other startup services. In our case this is a bad thing as setting up
the ramdisks has to be done before any other services are started. To
accomplish this the rcS hack has been migrated to a systemd service
running before basic.target and with DefaultDependencies=no. This has a
similar effect as the rcS hack because normal systemd services (with
DefaultDependencies=yes) all require basic.target by default.
The POSBox attempts to maintain whatever Wi-Fi connection it has as best
it can. When it loses it's current Wi-Fi connection it will attempt
to recreate it every 30 seconds. This works well, but a side-effect of
this is that it'll also print a 'Could not connect to LAN' ticket every
time it fails. If you where to leave the POSBox with Wi-Fi on for an
extended period of time you could return to a lot of 'Could not connect
to LAN' tickets.
This makes it so that the 'Could not connect to LAN' ticket only gets
printed once upon connection loss. Although it would be simpler to just
not print this ticket at all when losing connection, it is very useful
to know when the POSBox has lost connection. Otherwise when it loses
connection it would stop working and noone would know why.
Sometimes it's useful to ssh into a posbox to quickly troubleshoot an
issue. Talking customers through port forwarding is very difficult
however. We use ngrok to solve this issue.
This implements an interface that allows a user to enter an ngrok
authentication token. After this, ngrok can be started and we should be
able to remotely connect.
Note that ngrok does NOT run by default on the posbox. It can only be
started manually by the user.
This allows people to connect the posbox to networks using a wireless
network adapter.
When plugging in a USB Wi-Fi adapter and no network cable, the posbox
will boot and host its own Access Point called "Posbox". Users can
connect their device to this network and can then connect to the posbox
the usual way.
An interface for has been provided that also allows users to instruct
the posbox to connect to a different Wi-Fi network. This is useful when
the client is not running Odoo locally.
It is also possible to make this configuration persistent. With a
persistent Wi-Fi network configuration, the posbox will always try to
connect to the specified network after a reboot.
Attempts have been made to make the Wi-Fi connection as robust as
possible. Upon connection loss, the posbox will automatically attempt to
reconnect.
Joren Van Onder