What
It's a script to build a customized OpenWRT firmware image on a Linux x86_64 host (basic familiarity with OpenWRT is assumed).
If the generated image is flashed on a device it will try to automatically
set up extroot on any
(!) storage device plugged into the USB port (/dev/sda). Keep in
mind that this will erase any inserted storage device while the
router is in the initial setup phase! Unfortunately there's little
that can be done at that point to ask the user for confirmation.
Why
So that e.g. customers can buy a router on their own, flash our custom firmware, plug in a pendrive, and manage their SIP (telephony) node from our webapp.
How
Building
To build issue the following command: ./build.sh architecture variant device-profile, e.g.:
./build.sh ar71xx generic TLWDR4300./build.sh ramips mt7621 ZBT-WG3526
Results will be under build/OpenWrt-ImageBuilder-${architecture}_${variant}-for-linux-x86_64/bin/.
To see a list of available targets, run this in the ImageBuilder dir: make info.
If you want to change which OpenWRT version is used, then edit the relevant variables in build.sh (RELEASE, and RELEASE_NAME).
Setup stages
Blinking leds show which phase the extroot setup scripts are in. Consult the sources for details: autoprovision-functions.sh.
Stage 1: setup extroot
At the first boot after flashing the firmware the autoprovision script will
wait for anything (!) in /dev/sda to show up (that is >= 512M), then erase
it and set up a swap, an extroot, and a datafilesystem (for the remaining
space), and then reboot.
Stage 2: download and install some packages from the internet
Once it booted into the new extroot, it will continuously attempt to install some OpenWRT packages until an internet connection is set up on the router (either by using ssh or LuCI if you could fit it into the firmware).
Login
After flashing the firmware the router will have the standard
192.168.1.1 IP address.
By default the root passwd is not set, so the router will start telnet with no password. If you want to set up a password, then edit the stage 2 script: autoprovision-stage2.sh.
If a password is set, then telnet is disabled by OpenWRT and SSH will listen using the keys specified in authorized_keys.
Once connected, you can read the log with logread -f.
Status
This is more of a template than something standalone. You most
probably want to customize this script here and there; search for
CUSTOMIZE for places of interest.
Most importantly, set up a password and maybe an ssh key.
I've extracted this from a project of mine where OpenWRT nodes auto-provision themselves in 3 stages (stage 3 was a Python script for an app-level sync feature), but I thought it's useful enough for making it public.
At the time of writing it only supports a few ar71xx routers out of the box,
but it's easy to extend it.
Tested with
OpenWRT Chaos Calmer 15.05 RC1 on a TP-Link WDR4300.
Troubleshooting
Which file should I flash?
You should consult the OpenWRT documentation.
The produced firmware files should be somewhere around build/OpenWrt-ImageBuilder-15.05-ar71xx-generic.Linux-x86_64/bin/ar71xx.
In short:
-
You need a file with the name
-factory.binor-sysupgrade.bin. The former is to be used when you first install OpenWRT, the latter is when you upgrade an already installed OpenWRT. -
You must carefully pick the proper firmware file for your hardware version! I advise you to look up the wiki page for your hardware on the OpenWRT wiki, because most of them have a table of the released hardawre versions with comments on their status (sometimes new hardware revisions are only supported by the latest OpenWRT, which is not released yet).
Help! The build has finished but there's no firmware file!
If the build doesn't yield a firmware file (*-factory.bin and/or *-sysupgrade.bin):
when there's not enough space in the flash memory of the target device to install everything
then the OpenWRT ImageBuilder prints a hardly visible error into its flow of output and
silently continues. Look into build.sh and try to remove some packages
that you can live without.