[PATCH 3/3] P2P: Optimize scan frequencies list when re-joining a persistent group

[Peer, Ilan]

> -----Original Message-----
> From: Jouni Malinen [mailto:j at w1.fi]
> Sent: Sunday, March 29, 2015 10:34
> To: Peer, Ilan
> Cc: hostap at lists.shmoo.com; Stern, Avraham
> Subject: Re: [PATCH 3/3] P2P: Optimize scan frequencies list when re-joining
> a persistent group
> 
> On Sun, Mar 22, 2015 at 08:20:35PM +0000, Peer, Ilan wrote:
> > On ?', 2015-03-22 at 21:17 +0200, Jouni Malinen wrote:
> > > On Mon, Mar 16, 2015 at 01:20:03AM -0400, Ilan Peer wrote:
> > > > When starting a P2P client to re-join a persistent group
> > > > (P2P_GROUP_ADD persistent=<id>), it is possible that the P2P GO
> > > > was already found in previous scans. Try to get the P2P GO
> > > > operating frequency from the scan results list so wpa_supplicant
> > > > will initially scan only the P2P GO known operating frequency.
> > >
> > > > diff --git a/wpa_supplicant/p2p_supplicant.c
> > > > b/wpa_supplicant/p2p_supplicant.c @@ -5504,18 +5504,26 @@ int
> > > > wpas_p2p_group_add_persistent(struct wpa_supplicant *wpa_s,
> > > > +	} else if (ssid->mode == WPAS_MODE_INFRA) {
> > > > +		freq = wpas_p2p_select_go_freq(wpa_s, neg_freq);
> > >
> > > That looks suspicious.. wpas_p2p_select_go_freq() is used only on
> > > the GO device, so this cannot really be correct.
> >
> > Indeed. But it seems that android (display) is using this API to
> > re-start a client as well. I'll try to get a log that shows this.
> 
> "P2P_GROUP_ADD persistent=<id>" can indeed start a P2P Client. I was not
> talking about that; I was talking about how wpas_p2p_select_go_freq() is
> used. It does not get called if the local device is a P2P Client in the persistent
> group that gets restarted with P2P_GROUP_ADD.
> 
> wpas_p2p_select_go_freq() figures out the best channel a new GO instance
> should be started on. It does not really make any sense to call it in P2P Client
> case where you need to figure out what is the operating channel of a peer
> device.
> 

Ok. Will fix.

Thanks,

Ilan.