This HOWTO describes how to generate a set of ipkg modules for 
providing support of freeDiameter in an OpenWRT system.

This HOWTO is written for OpenWRT 10.03 (BackFire) and no guarantee is provided
that it will work for you. Be prepared to eventually brick your routeur...

Table of contents:
1) Prerequisites: get the OpenWRT development environment ready.
2) Supplied packages: use the existing packages when possible (gnutls, ...)
3) Other dependencies: provide for additional missing dependencies (sctp ...)
4) freediameter package: now create the freeDiameter package
5) Configuration: how to set the configuration on the router.

This HOWTO will NOT cover how to install OpenWRT on your access device, nor 
its basic configuration. Please refer to OpenWRT website for this type of HOWTOs.



==============================================
1) Prerequisites:
==============================================

We will first need a working OpenWRT toolchain environment. You can retrieve
pre-compiled binaries of such toolchains ("Image builder") on the OpenWRT website. Anyway,
in case the architecture you are interested in is not listed, you can build
the full toolchain from source. This is the path we are following in this HOWTO.

a) Retrieve the latest OpenWRT source, using subversion or git.
Since I have to go through a proxy, I use the later here, svn being quite annoying with proxies.
Note, the following commands must not be run as root.
$ git clone git://nbd.name/openwrt.git
 (Note: you might instead use "backfire.git" if you want to stick with an OpenWRT release.)
$ cd openwrt
$ cp feeds.conf.default feeds.conf

b) If you are using git, you have to edit the feeds.conf file to use git as well for packages.
Do the following modifications in this case:
$ vi feeds.conf
 Comment out this line:
src-svn packages https://svn.openwrt.org/openwrt/packages
 Add this line instead:
src-git packages git://nbd.name/packages.git

 You can leave uncommented the luci (for GNUTLS) and Xwrt (webif) repositories. Since these repositories
use svn over http, you can use subversion even if you are behind a proxy.

c) Then issue the following command to update the package list:
$ scripts/feeds update

d) Now, let's already create the toolchain and basic image.
$ make menuconfig

This will open a menu for you. You must select the target you are building for.
See http://wiki.openwrt.org/toh/start for the table of hardware and associated information.
In my case, I am using a Buffalo WZR-HP-G300NH router. I therefore select these options:
- Target System --->
   Atheros AR71xx/AR7240/AR913x
- Target Profile --->
   Buffalo WZR-HP-G300NH
   
For many routeurs, the recommended kernel is a 2.4x version. I have NOT tried with such kernel,
and the SCTP support is likely to be different in this generation of kernels. I strongly recommend
to go with a 2.6x kernel, whenever possible. 
   
e) Once configured, create the toolchain and default image (this takes a while):
$ make

After this command completes successfully, your build environment is ready.
The resulting image and packages are stored in the "bin/" subdirectory.
It is very convenient if you make this repository available in http to your routeur.

You should probably try at this early stage to flash your device with the image you have generated.
If the default basic image does not work, it is probably not worth adding new problems on top of it.

For troubleshooting, please consult OpenWRT documentation directly.
"make prereq" may help you building the initial image also.
See http://downloads.openwrt.org/docs/buildroot-documentation.html for additional information
concerning this step.

You should now be able to login on your routeur with telnet (first time) or ssh (after setting a password).

==============================================
2) Supplied packages:
==============================================

There are some dependencies of freeDiameter already available in the OpenWRT packages repository. 
You can check for the available packages with the script:
$ ./scripts/feeds search <package>

We will now describe how to install these dependencies. At the time this HOWTO is written, 
the OpenWRT repositories contain ipv6, gnutls, pthreads and hostapd. Follow these instruction to
build them:

a) GNU TLS packages
$ scripts/feeds install libgnutls

b) Select the following components in the menu:
$ make menuconfig
- Base system --->
   libpthread (M)
   
- Network --->
   hostapd (M)
   wpad-mini ( )

- Libraries --->
   SSL --->
     libgnutls (M)
   
- Kernel modules --->
   Network Support --->
     kmod-ipv6 (M)
     
Quit and save the new config, then:
$ make world

This will add a bunch of modules in your bin directory that will be required for freeDiameter.
Since we are removing the wpad-mini daemon from the base image, this image (trx or bin file) is also recompiled.

Note that if you are setting your device as WPA supplicant also (wireless client), you can select wpad instead of hostapd.
(in any case, the -mini version is not suitable since we will use the RADIUS authentication).


You should now reflash your routeur with the new firmware image. The simplest way to achieve if your routeur has enough
flash memory is to:
- copy the new trx image to your routeur's /tmp (using wget or scp)
- run this command (on the device) -- replace <newfile.trx> with your actual filename:
 root@OpenWrt:~# mtd -r write <newfile.trx> linux

WARNING: this will erase your existing configuration on the routeur. 
In case you need to save it, you may try the sysupgrade command instead.

This will reboot the device after writing the new image file.
Afterwards, if you have set up the http server on your development machine properly 
(let's assume it has IP address 192.168.1.25)
you can run the following command on your router:
 root@OpenWrt:~# echo "src/gz mydev http://192.168.1.25/packages" >> /etc/opkg.conf 
 root@OpenWrt:~# opkg update

Install the newly compiled packages with:
 root@OpenWrt:~# opkg install kmod-ipv6 hostapd libpthread

==============================================
3) Missing packages:
==============================================

There are other dependencies for freeDiameter that are not provided by OpenWRT packages. 
For convenience, we include these meta-packages in the freeDiameter distribution -- but they
might not be up-to-date.

a) Adding the contributed directory to the feeds
  Add the following line in your feeds.conf file:
src-link freediameter /path/to/freediameter/contrib/OpenWRT/packages/

Then run: 
$ scripts/feeds update

This should allow you to install the missing dependencies as follow:


b) SCTP library (note: you might alternatively compile freeDiameter without SCTP support).
$ scripts/feeds install sctp


c) Select these components in the menu:
$ make menuconfig
- Libraries --->
   sctp (M)

Quit and save the new config, then:
$ make world


d) Install this on the router as well:
 root@OpenWrt:~# opkg update
 root@OpenWrt:~# opkg install sctp


==============================================
4) freediameter package:
==============================================

Now, your environment should be ready to compile the freeDiameter ipkg package.
$ ./scripts/feeds install freediameter

Note that in order to build this package, you need to have cmake on your compilation machine.

$ make menuconfig
- Network --->
   freeDiameter (M)
   
Quit and save the new config, then:
$ make world