Adding a vendor Information Element to beacon / probe response frames
Arend van Spriel
arend.vanspriel at broadcom.com
Fri Jun 17 22:22:52 PDT 2016
On 17-06-16 22:53, Etan Kissling wrote:
> Thanks for the response.
> Good to hear that there are no known issues about this topic from the hostap front.
> The Raspberry 3 chip is Broadcom BCM43438.
> The chip I've used with Raspberry 1 in the dongle is Broadcom BCM43143.
> I'll check the driver. Can't imagine that the hardware doesn't support it,
> as appending static data to a packet shouldn't be a difficult to implement feature.
Difficulty is hardly ever a reason for not implementing a feature. The
firmware for these broadcom chips is running a 802.11 stack and as such
it determines most part of the beacon, proberesp, etc.
That being said there is a firmware api to add vendor IEs. You can check
the function brcmf_vif_set_mgmt_ie() which you find in cfg80211.c of the
brcmfmac driver. Loading the driver with debug=6 should make the
following debug print show up:
brcmf_dbg(TRACE, "ADDED ID : %d, Len: %d, OUI:%02x:%02x:%02x\n",
There are also a couple of error prints, but those would show up anyway.
Hope this helps.
>> On 17 Jun 2016, at 22:40, Jouni Malinen <j at w1.fi> wrote:
>> On Wed, Jun 15, 2016 at 02:13:14PM +0000, Etan Kissling wrote:
>>> I've retried with the latest hostapd release, but same result: The vendor IE is not being broadcast, although it is specified in hostapd.conf.
>>> These were my complete steps, from a clean Raspbian Jessie Lite 2016-05-27 installation on a Raspberry Pi 3 Model B.
>> It sounds like the driver used on that device does not support this.
>> hostapd is requesting it to be added, as shown here:
>>> + vendor_elements=DD0401020300
>>> nl80211: Set beacon (beacon_set=0)
>>> nl80211: Beacon tail - hexdump(len=15): 2a 01 04 32 04 30 48 60 6c dd 04 01 02 03 00
>> The extra element is there at the end of the Beacon tail..
>>> nl80211: beacon_ies - hexdump(len=6): dd 04 01 02 03 00
>>> nl80211: proberesp_ies - hexdump(len=6): dd 04 01 02 03 00
>> And also in the specific IE lists for Beacon and Probe Response frames..
>> In other words, this question should be directed to whoever supports the
>> specific Wi-Fi hardware/driver.
>> Jouni Malinen PGP id EFC895FA
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