P2P_DEVICE support in Android KitKat

[Arend van Spriel]

On 10-09-14 16:15, Arend van Spriel wrote:
> On 09/10/14 13:10, Jouni Malinen wrote:
>> On Wed, Sep 10, 2014 at 09:30:05AM +0200, Arend van Spriel wrote:
>>> I am running some tests on a haswell target with Android KitKat
>>> (3.10.20 kernel). In this configuration our brcmfmac driver is used
>>> with driver param 'p2p_device=1'. So we end up with wlan0 and
>>> p2p-dev-wlan0 interfaces (can blame myself for that). The
>>> configuration has a network configured, but I did not expect
>>> wpa_supplicant to start association using the p2p device interface.
>>> The wlan0 interface is already connected to the AP. How can I fix
>>> this to assure p2p-dev-wlan0 is only used for p2p management
>>> scenarios.
>>
>> Hmm.. Can you please show the wpa_supplicant command line that is used
>> here and describe how that network block gets configured for the
>> p2p-dev-wlan0 "interface"? I would have expected that there would never
>> be a configuration with an enabled network block being passed for the
>> P2P management interface.. Internally, wpa_supplicant should not add
>> such for P2P groups, but I don't think there is any filtering on
>> configuration if something is externally trying to make wpa_supplicant
>> use that management interface for a station mode connection.
> 
> Hi Jouni,
> 
> Jithu informed me about the '-m' command line option so digging in git
> revision history I found the commit from Ilan which kind of describes
> what I am seeing
> 
> c16a759 wpa_supplicant: Add a configuration file for the P2P_DEVICE
> parameters
> 
> Here is p2p_supplicant service instantiating the wpa_supplicant.
> 
> service p2p_supplicant /system/bin/wpa_supplicant -Dnl80211 -iwlan0 \
>   -g at android:wpa_wlan0 -c/data/misc/wifi/p2p_supplicant.conf -dt
> 
> The p2p_supplicant.conf has update_config=1 set which is also mentioned
> in the commit message. Without -m option p2p-dev-wlan0 is created using
> the same config file as for wlan0 so some filtering would be required
> (or use -m).

Although the -m may work it feels somewhat awkward. My idea behind the
P2P_DEVICE functionality was to have simpler command line with just the
primary interface and a single configuration file. With that in mind I
created a patch filtering the networks so they do not get enabled for
the P2P_DEVICE interface. That seems to be working, but I will do some
more testing with it.

Regards,
Arend