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Broadcom bcm43xx

As of 2.6.17, a driver for the Broadcom bcm43xx wireless chipset has been included in the kernel. Older kernels can sometimes be made to work, check out resources available here While this driver natively supports monitor mode, it requires patching before packet injection can be done. After testing aireplay-ng with the patches, please contribute to the forum thread by reporting any successes or failures there.

Patching the kernel

  • Download the bcm43xx inject_nofcs patch for the 2.6.20 kernel from here.
  • Place the patch in your kernel sources directory
  • Run 'patch -p1 -i bcm43xx-injection-linux-2.6.20.patch'.

This patch may not apply directly and may require that you modify the bcm43xx_main.c (located in $linux/wireless/net/drivers/bcm43xx/ manually)

  • Recompile your modules with 'make modules' followed by 'make modules_install'.
  • The module should now be ready to use for injection.
  • Remember to reload the kernel driver or reboot your system before trying to inject packets.

Testing the new module

After building and installing the new module, it is best to test that injection is working correctly. Use the injection test to confirm your card can inject.

Usage Tips

Forum thread: The complete how to of making bcm43xx injection work

This forum thread may also provide some useful information: Broadcom bcm43xx Injection

Known problems

The bcm43xx has been verified to produce all attacks. However, there a few known problems.

  • aireplay exits with “out of memory error” / syslog shows “out of DMA slots”

There is a problem in the bcm43xx driver when injecting packets using DMA access. I'll try to compile the mod without DMA and see what happens asap. I'll also make another patch soon that waits till the send buffer is empty before resuming after an error occured. Now it just waits a second before resuming at a lower rate.

  • packets per second is adjusted to around 25 pps

Same problem as above, there is a problem with injection and DMA access.

  • syslog shows a lot of failed assertions (!ring→suspended).

ASSERTION FAILED (!ring→suspended) at: drivers/net/wireless/bcm43xx/bcm43xx_dma.c:71:request_slot(). Again, a problem with DMA. Aireplay tries to write a packet, the driver wants a free DMA slot for that and can't because the DMA slots were all taken (the driver blocks all dma requests then).

Troubleshooting Tips

First, double check that you are in fact running the new module:

 modinfo bcm43xx

It will give you the fully qualified file name. Do “ls -l <fully qualified file name>” and confirm it has the date/time of when you compiled and installed the new module. If it does not match, then you are not running the patched module. This would, of course, need to be fixed.

This thread has a number of potential fixes to problems you may encounter: Broadcom bcm43xx Injection

broadcom.1184800971.txt.gz · Last modified: 2007/07/19 01:22 by darkaudax