Wifi Direct GO Negotiation
Arend van Spriel
arend
Thu May 15 12:27:28 PDT 2014
On 05/15/14 18:25, Andrea Chittano wrote:
> Sorry guys for my inexperience, but this thing are driving me mad.
>
> Tell me if i'm wrong.
> Does the function at line 525 of the following link
>
> http://code.metager.de/source/xref/hostapd-wpa_supplicant/src/p2p/p2p_go_neg.c?r=0e0e1e564f3dd8d2a6b645d079b46eba0acc7f83
>
> that is
>
> *void* p2p_process_go_neg_req <http://code.metager.de/source/s?defs=p2p_process_go_neg_req&project=hostapd-wpa_supplicant>(*struct* p2p_data <http://code.metager.de/source/s?defs=p2p_data&project=hostapd-wpa_supplicant> *p2p <http://code.metager.de/source/s?defs=p2p&project=hostapd-wpa_supplicant>,*const* u8 <http://code.metager.de/source/s?defs=u8&project=hostapd-wpa_supplicant> *sa <http://code.metager.de/source/s?defs=sa&project=hostapd-wpa_supplicant>,
> *const* u8 <http://code.metager.de/source/s?defs=u8&project=hostapd-wpa_supplicant> *data <http://code.metager.de/source/s?defs=data&project=hostapd-wpa_supplicant>,size_t <http://code.metager.de/source/s?defs=size_t&project=hostapd-wpa_supplicant> len <http://code.metager.de/source/s?defs=len&project=hostapd-wpa_supplicant>,*int* rx_freq <http://code.metager.de/source/s?defs=rx_freq&project=hostapd-wpa_supplicant>)
>
>
> represent the processing (performed by Device2) of the GO negotiation
> request that Device1 sent Device2?
>
> This function performs at line 687
>
> p2p_go_det <http://code.metager.de/source/s?refs=p2p_go_det&project=hostapd-wpa_supplicant>(p2p <http://code.metager.de/source/s?defs=p2p&project=hostapd-wpa_supplicant>->go_intent <http://code.metager.de/source/s?defs=go_intent&project=hostapd-wpa_supplicant>, *msg <http://code.metager.de/source/s?defs=msg&project=hostapd-wpa_supplicant>.go_inten <http://code.metager.de/source/s?defs=go_intent&project=hostapd-wpa_supplicant>t)
>
>
> which returns the highest GO intent between local GO intent and received
> one.
> If I'm not wrong, according to what Arend told me Device2 get local GO
> intent from wpa_supplicant configuration file. But I've found only one
> way to set the local GO intent and it is here :
>
> http://code.metager.de/source/xref/hostapd-wpa_supplicant/src/p2p/p2p.c
>
> at line 1387, into the function
>
> *int* p2p_connect <http://code.metager.de/source/s?refs=p2p_connect&project=hostapd-wpa_supplicant>(*struct* p2p_data <http://code.metager.de/source/s?defs=p2p_data&project=hostapd-wpa_supplicant> *p2p <http://code.metager.de/source/s?refs=p2p&project=hostapd-wpa_supplicant>,*const* u8 <http://code.metager.de/source/s?defs=u8&project=hostapd-wpa_supplicant> *peer_addr <http://code.metager.de/source/s?refs=peer_addr&project=hostapd-wpa_supplicant>,
> *enum* p2p_wps_method <http://code.metager.de/source/s?defs=p2p_wps_method&project=hostapd-wpa_supplicant> wps_method <http://code.metager.de/source/s?defs=wps_method&project=hostapd-wpa_supplicant>,
> *int* go_intent <http://code.metager.de/source/s?defs=go_intent&project=hostapd-wpa_supplicant>,*const* u8 <http://code.metager.de/source/s?defs=u8&project=hostapd-wpa_supplicant> *own_interface_addr <http://code.metager.de/source/s?defs=own_interface_addr&project=hostapd-wpa_supplicant>,
> *unsigned* *int* force_freq <http://code.metager.de/source/s?defs=force_freq&project=hostapd-wpa_supplicant>,*int* persistent_group <http://code.metager.de/source/s?defs=persistent_group&project=hostapd-wpa_supplicant>,
> *const* u8 <http://code.metager.de/source/s?defs=u8&project=hostapd-wpa_supplicant> *force_ssid <http://code.metager.de/source/s?defs=force_ssid&project=hostapd-wpa_supplicant>,size_t <http://code.metager.de/source/s?defs=size_t&project=hostapd-wpa_supplicant> force_ssid_len <http://code.metager.de/source/s?defs=force_ssid_len&project=hostapd-wpa_supplicant>,
> *int* pd_before_go_neg <http://code.metager.de/source/xref/hostapd-wpa_supplicant/src/p2p/p2p.c#pd_before_go_neg>,*unsigned* *int* pref_freq <http://code.metager.de/source/s?defs=pref_freq&project=hostapd-wpa_supplicant>,u16 <http://code.metager.de/source/s?defs=u16&project=hostapd-wpa_supplicant> oob_pw_id <http://code.metager.de/source/s?defs=oob_pw_id&project=hostapd-wpa_supplicant>)
>
>
>
>
>
> According to what specifications say, it is used to start a GO negotiation.
> So my question is, how can I set the local GO intent for Device2 without
> using p2p_connect() function?
> I would make it by means of an android application. Can I do this?
Maybe it would help to give some high-level information on what you are
trying to do. I am not familiar with Android solution, but most likely
Android provides an API for applications that is handled by their
framework/middleware to get it in wpa_supplicant (see [1]).
Regards,
Arend
[1] http://developer.android.com/guide/topics/connectivity/wifip2p.html
> Thanks for your help.
> Andrea
>
>
> > Date: Wed, 14 May 2014 10:21:56 -0700
> > From: moon.linux at yahoo.com
> > Subject: Re: Wifi Direct GO Negotiation
> > To: arend at broadcom.com; andrea.chittano at hotmail.it
> > CC: hostap at lists.shmoo.com
> >
> > Hi Arend,
> >
> > I agree with what you said regarding the AP.
> >
> > One more question: Any device with WPS capabilty can join a P2P network.
> >
> > Thanks.
> > -Anand Moon
> >
> >
> >
> > On Wednesday, May 14, 2014 2:56 PM, Arend van Spriel
> <arend at broadcom.com> wrote:
> > On 14-05-14 05:03, Anand Moon wrote:
> > > Hi All,
> > >
> > > I would like to add new question to this thread.
> > >
> > > If the AP has the capability to support p2p and wps, how will
> > > these two devices communicate with the AP.
> > > Will this AP become P2P group owner (P2P Go) and the other devices
> P2P Clients ?
> >
> > I am not sure whether this scenario makes sense. P2P typically involves
> > two STAs. They may be connected to some AP, but if both are connected to
> > the same AP there may be not so much need to setup a P2P connection.
> >
> > > I would like to know how to judge if the wireless interface
> supports P2P
> > > is it with the "Supported interface modes" or "Supported RX frame
> types" ?
> > >
> > > If the device support following p2p mode then how do we need to
> configure them.
> > >
> > > Supported interface modes:
> > > * IBSS
> > > * managed
> > > * AP * AP/VLAN
> > > * monitor
> > > * mesh point
> > > * P2P-client
> > > * P2P-GO
> > >
> > > How do we configure these P2P modes for interface?
> > > Please share your thoughts.
> >
> > Just use nl80211 API, ie. NL80211_CMD_SET_INTERFACE. wpa_supplicant is
> > doing that in src/drivers/driver_nl80211.c
> >
> > Regards,
> > Arend
> >
> >
> > > -Anand Moon
> > >
> > >
> > > On Tuesday, May 13, 2014 6:31 PM, Arend van Spriel
> <arend at broadcom.com> wrote:
> > > On 05/13/14 14:03, Andrea Chittano wrote:
> > >> Hi, my name is Andrea.
> > >> I'm working on WiFi Direct and I found a thread about it.
> > >> I've some doubts about it.
> > >> Let's suppose we have 2 devices. Let's call D1 and D2.
> > >> Let's suppose D1 sends a request of connection to D2 (D1 doesn't known
> > >> D2 so no persistent connection there exist).
> > >> The first step that wpa_supplicant on D1 is to send a GO negotiation
> > >> request containing, among all,GO intent (of D1).
> > >> I want to understand how wpa_supplicant on D2 acquires the GO
> intent of
> > >> D2 in order to compare it with whichone sent by D1.
> > >> Can someone explain me this?
> > >
> > > Both devices have their own go intent configuration in wpa_supplicant
> > > configuration file. D2 sends own go intent value in the GO negotiation
> > > response. The device with the highest GO intent will become GO.
> > >
> > > Regards,
> > > Arend
> > >
> > >> Thanks,
> > >> Andrea
> > >>
> > >>
> > >>
> > >> _______________________________________________
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> > >> HostAP at lists.shmoo.com
> > >> http://lists.shmoo.com/mailman/listinfo/hostap
> > >
> > >
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> > >
> >
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