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Create OpenWrt bin image including openvswitch and the ath9k patch

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Jose Saldana edited this page May 15, 2020 · 46 revisions

UNDER CONSTRUCTION

Supported routers

We are using the next routers, which run with ath9k driver:

We are connecting to them an extra WiFi interface: the USB TP-Link TL-WN722N (also uses ath9k driver). Some of the experiences we are adding here may only be valid for this particular hardware, and may require an adaptation before being useful for other hardware.

Options

You have three different options:

  1. If you have any of the supported routers, you will find the .bin files here, so you can skip this step and flash them directly.

  2. There is a script that automatically builds an OpenWrt image which you can flash in your AP. You can find it here: (https://github.com/Wi5/odin-wi5/tree/master/Odin_Wi5_firmware_build

  3. You can follow the next steps. Note: They are valid for OpenWrt 15.05.1

Install the required packages (building environment) in a PC where you are going to compile.

If you don’t have them, install these tools as root: ncurses, svn, awk, build-essential, git

  • In Debian, you can use:

      apt-get update
  apt-get install ncurses subversion gawk build-essential git
  apt-get install libssl-dev zlibc

  • In Ubuntu, you can do:

      apt-get update
  apt-get install subversion libssl-dev zlibc zlib1g zlib1g-dev gzip 
  apt-get install gawk libncurses5-dev git build-essential

Building an OpenWrt image

Clone OpenWrt sources

Create the folder were the source will be downloaded (e.g. openwrt )

  ~$ mkdir openwrt
  ~$ cd openwrt

Clone the repository from git (https://dev.openwrt.org/wiki/GetSource)

  ~/openwrt$ git clone git://git.archive.openwrt.org/15.05/openwrt.git trunk

Configure OpenWrt sources

We are going to add some extra packages to the OpenWrt sources:

  • Move feeds.conf.default to feeds.conf

      ~/openwrt/trunk$ mv feeds.conf.default feeds.conf

  • Prepare menuconfig, to add some optional packages (including openvswitch). The configurations of menuconfig are stored in the .config file.

Note: If you want to reset your menuconfig, just delete the .config file.

  • Update the menuconfig with the new sources (make sure you are connected to the Internet) with:

      ~/openwrt/trunk$ ./scripts/feeds update -a

  • Add all the packages to OpenWrt sources:

      ~/openwrt/trunk$ ./scripts/feeds install -a

Note: With –a, you will install all possible packages. Another option is to install per-package (-p). You can then install individual packages. For example, if you only want to add Luci to the menuconfig:

    ~/openwrt/trunk$ ./scripts/feeds install -a -p luci

Select the architecture through the menuconfig 

    ~/openwrt/trunk$ make menuconfig
  • Select your architecture:
  'Target System': Atheros AR71xxx/Ar9xxx
  • Select the Subtarget:

For Netgear 6100 use:

Generic devices with nand flash

For TP-Link AC1750 use:

Generic devices
  • Select your device
  'Target Profile': Netgear R6100

  'Target Profile': TP-LINK Archer C5/C7

  • Select squashfs in Target images. This way, you will be able to flash the new firmware maintaining the configuration files.

  • Save and exit menuconfig.

create a default .config for the choosen architecture:

   ~/openwrt/trunk$ make defconfig

Check prerequisites:

   ~/openwrt/trunk$ make prereq

Now, you have a complete environment for cross-compilation in OpenWrt.

Select the packages through the menuconfig

Run again the menuconfig to configure the sources:

    ~/openwrt/trunk$ make menuconfig

Note: If you use <*> it compiles the package and adds it to the .bin firmware. You should use this option.

If you use <M> it compiles the package but it does not add it to the .bin firmware.

  • Select Luci

         Luci / Collections / Luci

  • Select nano and joe editors you like the most:

         Utilities / editors / nano
     Utilities / editors / joe

  • In order to support c++ calls, select:

         Base system / libstdcpp		GNU Standard C++ Library v3

  • In order to support USB drives, select:

        kernel modules / USB support / kmod-usb-storage

    Kernel modules / filesystems / kmod-fs-ext4

                                 / kmod-fs-msdos

                                 / kmod-fs-vfat

    Native language support      / kmod-nls-cp437

  • Install hostapd utils

        Network / hostapd-utils

They are needed in order to change the channel of the auxiliary interface.

  • Install support for tun/tap interface

        Kernel modules / Network Support  / kmod-tun

  • Optional. Install the dummy network interface (may be needed if you don't have a secondary wireless interface)

        Kernel modules / Network Devices / kmod-dummy

  • Optional. Install the ip link commmand (may be needed if you don't have a secondary wireless interface)

        Base system / Busybox / Networking utilities / ip link

  • Again in Network, install tcpdump:

        Network / tcpdump

  • Again in Network, install openvswitch modules and requirements:

        Network   /   openvswitchswitch
              /   openvswitch-ipsec

    Kernel modules / Cryptographic API modules / kmod-crypto-crc32c

    Kernel modules / Libraries  /	kmod-lib-crc32c

  • Optional. If you want to use confuselibrary, add it in:

        Libraries / confuse

  • Add the Support for wireless debugging in ath9k driver (this will call debug.c).

        Kernel modules / Wireless drivers / kmod-ath / Atheros wireless debugging

    Note: This will set the flag CONFIG_PACKAGE_ATH_DEBUG=y in the .conf file.

  • Optional. In order to avoid that the image you are trying to build is too big for the device, we will remove some packages (note that we have selected these, but others could also be removed):

        Network / odhcpd
    Network / odhcp6c

  • Remove the "CONFIG_USE_MIPS16=y" option. Uncheck the MIPS16 option:

        Advanced config. options/ Target opt./ Build packages with MIPS16 instructions

  • Add the drivers for 802.11 devices. In our case, we are using ath9k in the main interface, and also in an extra wireless interface (TP-Link TL-WN722N). So you have to mark the driver:

        Kernel modules / Wireless drivers / kmod-ath9k-htc

Note. Do not mark other drivers, as then OpenWrt may use them for the main wireless card instead of ath9k.

  • Save and exit from menuconfig. The changes will be written to .config.

Do the final build

Check the prerequisites

      ~/openwrt/trunk$ make prereq

In order to cross-compile a complete OpenWrt, run:

       ~/openwrt/trunk$ make

(This may take several minutes)

Note: If you want to use more threads, use make -j 4 (this is for 4 threads). Be careful, depending on the number of threads supported by your computer.

Note: If you want to see in detail what is going on, run $ make V=s

If you have added Openvswitch, you may obtain a message WARNING: your configuration is out of sync. Please run make menuconfig, oldconfig or defconfig! It is not important.

If your computer does not find any of the required packages, you can edit trunk/scripts/download.pl, and add www.kernel.org:

            foreach my $dir (@extra) {
                    push @mirrors, "https://www.kernel.org/pub/$dir";
                    push @mirrors, "http://www.kernel.org/pub/$dir";
                    push @mirrors, "ftp://kernel.org/pub/$dir";
            }

(...)

            push @mirrors, 'http://mirror1.openwrt.org';
            push @mirrors, 'http://mirror2.openwrt.org/sources';
            push @mirrors, 'http://downloads.openwrt.org/sources';
            push @mirrors, 'https://www.kernel.org/pub/linux/kernel/v3.x';
            push @mirrors, 'http://www.kernel.org/pub/linux/kernel/v3.x';

Patch the wireless driver

You have to patch the debug.c file. The idea is that you include some new functions there, in order to modify the mask that allows the AP to send the layer-2 ACKs. Odin makes use of the debugging tools for the drivers (https://wireless.wiki.kernel.org/en/users/drivers/ath9k/debug). It creates a file called /sys/kernel/debug/ieee80211/phy0/ath9k/bssid_extra, where the mask is stored. The driver will use it in order to decide if a frame is targeted to it, and therefore send a layer-2 ACK.

Note. A device in monitor mode does not send layer-2 ACKs. Therefore, we will create an e.g. mon0 device in addition to the e.g. wlan0, but both interfaces must be up.

Find the correct debug.c file and patch it

The good one is this one (45324 bytes): ~/openwrt/trunk/build_dir/target-mips_34kc_uClibc-0.9.33.2/linux-ar71xx_generic/compat-wireless-2014-05-22/drivers/net/wireless/ath/ath9k/debug.c

Apply the patch on it

The patch is here: https://github.com/Wi5/odin-wi5/blob/master/odin-patch-driver-ath9k/ath9k-bssid-mask.patch

  • Apply the patch with this command:

       ~/openwrt/trunk/build_dir/target-mips_34kc_uClibc-0.9.33.2/linux-ar71xx_generic/compat-wireless-2016-01-10/drivers/net/wireless/ath/ath9k$ patch debug.c < /home/intelnuc/openwrt_compile_environment/ath9k-bssid-mask.patch

You should see this result:

     patching file debug.c
     Hunk #1 succeeded at 862 with fuzz 2 (offset -125 lines).
     Hunk #2 succeeded at 1601 (offset 17 lines).

Note. You may find some help in https://www.cyberciti.biz/faq/appy-patch-file-using-patch-command/

  • If it does not work, you can apply the patch manually (i.e. manually editing the file and adding the two hunks in their corresponding places.

  • Substitute the file debug.c by the patched one in this directory of the machine where you are compiling.

       ~/openwrt/trunk/build_dir/target-mips_34kc_uClibc-0.9.33.2/linux-ar71xx_generic/compat-wireless-201x-yy-zz/drivers/net/wireless/ath/ath9k/

Remove some files which will have to be recompiled later

  • Remove all the .o and .ko files in the (...)/drivers/net/wireless/ath/ath9k directory and do NOT run make clean.

*Also remove this .ko file:

     ~/openwrt/trunk$ rm build_dir/target-mips_34kc_uClibc-0.9.33.2/linux-ar71xx_generic/compat-wireless-201x-yy-zz/ipkg-ar71xx/kmod-ath9k/lib/modules/3.18.tt/ath9k.ko

Build again

Now, you have to compile and build again. You will not have to compile everything, because you have NOT run make clean. Only the things that have been changed will be recompiled:

      ~/openwrt/trunk$ make

If you have added Openvswitch, you may obtain a WARNING: your configuration is out of sync. Please run make menuconfig, oldconfig or defconfig! It is not important.

After the compilation, the directory ~/openwrt/trunk/bin/ar71xx contains the .bin files that can be flashed in the router:

  • TPLink1043: openwrt-ar71xx-generic-tl-wr1043nd-v2-squashfs-sysupgrade.bin

  • Archer C5/C7: openwrt-ar71xx-generic-archer-c7-v2-squashfs-sysupgrade.bin

Note: You may have some problems with the size of the .bin files. In these cases, you will not obtain some of the .bin files. You will then have to remove some packages (don't remove kmod-* packages).

Flash the .bin file in your device

If the router has the default TP-link firmware

Take a PC and add an Eth address 192.168.0.x. Connect it to one of the yellow Eth ports of the wireless router. Open the web of the wireless router. In TPLink AC1750 Archer C7, it is 192.168.0.1. (user: admin, password: admin). Go to “System tools / firmware update” and select the .bin file you have just built.

Once it installs OpenWrt, the router is rebooted.

The first time you log in, you must do it with Telnet (use Putty). Take the PC and modify the Eth address to 192.168.1.x. Connect it to one of the yellow Eth ports of the wireless router.

Do just a Telnet to the default IP address of OpenWrt (it is 192.168.1.1), and you will not be requested a password (http://wiki.openwrt.org/doc/howto/firstlogin).

Run root@OpenWrt:/# passwd and set a password for root.

Then, you will be able to use SSH, so disconnect and try with SSH.

If the router has the default Netgear R6100 firmware

Put the network card of your computer in DHCP mode.

Connect a wire from your computer to one of the Ethernet (black) ports of the Netgear router.

Open www.routerlogin.net in your browser. You will see the internal web page of the router.

Go to Advanced / Administration / Firmware Upgrade

Select the file openwrt-ar71xx-nand-r6100-ubi-factory.img, which you have to download to your computer.

After flashing it, you will be able to access the OpenWrt firmware in 192.168.1.1

Go to System Administration / Router Password, and set a new password. Tick "Allow remote hosts to connect to local SSH forwarded ports". Save & Apply. Reboot the router.

If the router already has OpenWrt

(See http://wiki.openwrt.org/doc/howto/generic.sysupgrade).

Copy the file openwrt-ar71xx-generic-tl-wr1043nd-v2-squashfs-sysupgrade.bin to the router.

Log in the router

     $ ssh [email protected]

Run this command

     $ sysupgrade openwrt-ar71xx-generic-tl-wr1043nd-v2-squashfs-sysupgrade.bin
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