wpa_supplicant 2.2 and P2P group negociation

Fleter, Franck franck.fleter at intel.com
Fri Sep 26 13:40:46 EDT 2014


I am using wpa_supplicant on Edison platform (kernel 3.10.17)
and I have an issue with the group negociation when Edison device
tries to become GO (intent value is 15).

When the P2P virtual group interface is created and first action frame sent,
I have the event RTM_NEWLINKwith the interface state not yet UP since the group negociation
is not yet completed. See trace below :

   .....
   nl80211: Frame TX command accepted; cookie 0x6
   RTM_NEWLINK: ifi_index=17 ifname=p2p-wlan0-0 operstate=2 linkmode=0 ifi_flags=0x1002 ()
   Could not read interface p2p-dev-wlan0 flags : No such device

The problem is that the rest of processing in this situation shuts down the interface
and group negociation fails.

The current WLAN driver/chipset on Edison, works fine one platform Android/Kitkat 4.4.2.
On Android, for the same sequence, I have the below traces :

   .....
   nl80211: Frame TX command accepted; cookie 0x9
   nl80211: Ignore RTM_NEWLINK event for foreign ifindex 5
   ......

By looking at the diff between the 2 supplicants, I can see one diff related to the above
traces. The function have_ifidx() always returns 0 on Android and the codes is only built under flag HOSTAPD.
Now, when I apply this small patch to the Linux wpa_supplicant 2.2, the group negociation works fine
(I have the above trace "Ignore ...", the interface becomes UP after negociation) but the side-effect is that
the wpa_supplicant 2.2 crashes on "wpa_cli p2p_group_remove ...".
There is memory corruption that makes the sendto() on wpa_cli unix socket
crashing when sending the response after the removal.

I am wondering who is faultly in this case.
Is there a bug in wpa_supplicant 2.2 regarding have_ifidx() vs P2P sequence or
there would be an issue in the driver regarding  the state of P2P virtual group interface ?


Thanks in advance,
  Franck

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