execute wpa_supplicant + wpa_cli with a virtual network interface

[Dan Williams]

On Thu, 2015-01-08 at 20:28 +0000, Stefano Cappa wrote:
> Oh damn!
> Thank u for this quick answer, now i'm really scared :(
> 
> If i use iw (ok not exactly iw, but an unofficial port of iw that i compiled) on Nexus 5 KitKat i get this:

Instead of iw directly, does any of the stuff mentioned here with
wpa_supplicant work?  eg, letting the supplicant handle creation of the
other interface if it needs to?

http://wireless.kernel.org/en/developers/p2p/howto

Dan

> |Supported interface modes:
> |		 * IBSS
> |		 * managed
> |		 * AP
> |		 * P2P-client
> |		 * P2P-GO
> |	software interface modes (can always be added):
> |	valid interface combinations:
> |		 * #{ managed } <= 2, #{ P2P-client, P2P-GO } <= 2, #{ IBSS } <= 1,
> |		   total <= 3, #channels <= 2
> *
> 
> On Nexus 4 Kitkat i get this:
> *
> |Supported interface modes:
> |		 * IBSS
> |		 * managed
> |		 * AP
> |		 * P2P-client
> |		 * P2P-GO
> |	software interface modes (can always be added):
> |	valid interface combinations:
> |		 * #{ managed } <= 3, #{ AP } <= 1, #{ P2P-client, P2P-GO } <= 1,
> |		   total <= 3, #channels <= 2
> *
> 
> This means that is supported for p2p with wpa_supplicant + wpa_cli? 
> I need to add another virtual interface for wpa_supplicant, because i want to work with p2p, for example "p2p1".
> 
> On nexus 5, If i try to create an interface with iw with this command: "iw dev wlan0 interface add p2p1 type managed"
> It works, i hope. And with "iw dev" i get :  
> 
> *
> |phy#0
> |	Interface p2p1
> |		ifindex 24
> |		type managed
> |	Interface wlan0
> |		ifindex 21
> |		type managed
> |	Interface p2p0
> |		ifindex 20
> |		type managed
> *
> 
> 
> 
> 
> With Nexus 4 the previous command works without errors, but the interface is not available with  "iw dev". I suppose that Nexus4 driver is not compatible.
> 
> 
> The question is: with Nexus 5, in this situation, it's possibile to execute wpa_supplicant on this new virtual interface? I know is the same question, but now i really want to be sure that this is the correct way, because i lost a huge amount of time.
> 
> Thank u very much Dan.
> 
> Stefano Cappa.
> 
> 
> ________________________________________
> Da: Dan Williams <dcbw at redhat.com>
> Inviato: gioved? 8 gennaio 2015 18.42
> A: Stefano Cappa
> Cc: hostap at lists.shmoo.com
> Oggetto: Re: execute wpa_supplicant + wpa_cli with a virtual network interface
> 
> On Thu, 2015-01-08 at 16:48 +0000, Stefano Cappa wrote:
> > Hi, with Android Kitkat or Lollipop i can execute this commands without problems and use wpa_cli for p2p:
> >
> >
> > 1) wpa_supplicant -B -iwlan0 -Dnl80211 -c/data/misc/wifi/wpa_supplicant.conf -N -B -ip2p0 -Dnl80211 -c/data/misc/wifi/p2p_supplicant.conf
> >
> > 2) wpa_cli -ip2p0 -p/data/misc/wifi/sockets
> >
> >
> > Now, i want to create another network interface created in this way (with a "custom android kernel" to enable macvtap, from Android Open Source Project) :
> >
> > 1) ip link add link wlan0 name INTERFACE_NAME type macvtap
> >
> > 2) busybox ifconfig INTERFACE_NAME 10.169.129.42 netmask 255.255.248.0 up
> >
> > 3) busybox ifconfig -a                                   // and i can find the new network interface with MAC, IP... --> PERFECT
> >
> >
> > Now i want to execute wpa_supplicant and wpa_cli with this network interface called in this example "INTERFACE_NAME":
> >
> > If i try with
> >
> > 1) "wpa_supplicant -B -iINTERFACE_NAME -Dnl80211 -c/data/misc/wifi/INTERFACE_NAME_supplicant.conf"
> >
> > with a conf file like wpa_supplicant, exactly the same with ctrl_interface=/data/misc/wifi/sockets, i get this error code "255".
> 
> It is very unlikely this will work, because the macvtap interface is
> *not* a wifi/nl80211 interface at all, and wpa_supplicant will by trying
> to do nl80211 operations on it.
> 
> If you're trying to create multiple virtual WiFi interfaces that
> wpa_supplicant can control, then you need to use the 'iw' tool to create
> them, and the driver needs to support multi-VIF operations.  You can
> find out if the driver does this by running "iw phy phy0 info" and
> looking at "valid interface combinations".
> 
> Dan
> 
> > Probably there are no available sockets in /data/misc/wifi/sockets ? Or, I need to use another conf file? I really don't know.
> >
> >
> > I thought, mmm, i can use wpa_cli interface_add INTERFACE_NAME "" nl80211 /data/misc/wifi/sockets,
> >
> > but i get this error: "Failed to connect to non-global ctrl_ifname: wlan0  error: No such file or directory 255"
> >
> >
> > My questions are:
> >
> >  A)   How can i execute wpa_supplicant + wpa_cli on a virtuale network interface in android?
> >
> >  B)   I need to create new sockets? How? I can use socat?
> >
> >  C)   The syntax of  wpa_cli interface_add  is correct? Because i can't find a good documentation to this command. I searched in the source code to pass the parameters, but i'm not completely sure.
> >
> >
> > Thank u very much,
> >
> > please help me,  i'm working on this, since...i don't know... days days and days :(
> >
> >
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