Setup a WiFi-direct® network

Scenarios covered by 'Wi-Fi direct':

  • You can transfer data between devices without internet connection, router or any other connection type.
  • You can stream media, send a presentation or display a file on a button press
  • You can create a secure private network with DHCP server included

KEYWORDS

  • RaspberryPi
  • Wi-Fi Direct®
  • P2P GO mode

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Wi-Fi CERTIFIED Wi-Fi Direct® is a certification mark for devices supporting a technology that enables Wi-Fi devices to connect directly, making it simple and convenient to do things like print, share, sync and display.
Products bearing the Wi-Fi Direct certification mark can connect to one another without joining a traditional home, office or hotspot network.

System setup: RaspberryPi 3 Model B Plus Rev 1.3
OS: 2018-11-13-raspbian-stretch-full.imgs

RaspberryPi setup(server)

1. configure wpa_supplicant service to setup a 'Wi-Fi direct' server. edit wpa_supplicant.config

I'll use WPA supplicant service for network setup. It's a network service supporting WEP, WPA and WPA2; It implements key negotiation with a WPA authenticator and it controls the roaming and IEEE 802.11 authentication/association of the wireless driver.


$ sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
the file should look like: 
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=US

ap_scan=1
device_name=RPi_3_1
device_type=1-0050F204-1
driver_param=use_p2p_group_interface=1
driver_param=p2p_device=1
#log/debug settings
p2p_listen_reg_class=81
p2p_listen_channel=1
p2p_oper_reg_class=81
p2p_oper_channel=1
#
p2p_go_intent=1
p2p_go_ht40=1
2. kill wpa_supplicant service if it's already started. 

$ sudo killall wpa_supplicant
3. delete wlan0 setup file if it's already setup 

$ sudo rm /var/run/wpa_supplicant/wlan0
4. start wpa_supplicant service: 

$ sudo wpa_supplicant -B -i wlan0 -D nl80211 -c /etc/wpa_supplicant/wpa_supplicant.conf
$ reboot
Note:
IF the service started with success you can enter the console mode.

5. enter wpa_console: 

$ sudo wpa_cli -i wlan0
6. create group(access point)

We'll use command line interface for AP related commands


> p2p_group_add
Note:
this should generate a log with some data regarding the created access point.
in case it worked fine, it will also create a new interface named p2p-wlan0-0
if the group is created sucessfully nothing is returned besides OK and specifications of the AP.
if the group is not created, a error message with some reason will be returned
we can delete the group created with the command: p2p_group_remove p2p-wlan0-0

Free HTML5 Template by FreeHTML5.coAP creation. p2p-wlan0-0 interface created OK


7. for external connection/media transfer you need to generate a pin on the new interface 

$ wpa_cli -i p2p-wlan0-0
# generate a connection pin 

> wps_pin any
# or a specific pin: 1234 

> wps_pin any 1234
Note:
this pin is generated in case you need to send media to the device
For the permanent connection you need the SSID generated, in this case we have:
SSID:'DIRECT-F9' with the pass: 'LA0BiJhQ'
OK, now we have the setup up and running.

Client setup - the second RPi

Now, we want to connect to this WiFi-direct's AP another RaspberryPi
# enter wpa_supplicant console for interface wlan0 

$ sudo wpa_cli -i wlan0
# inside the console we need to join the group 

> p2p_connect < hw_address_for_p2p-wlan0-0 of the RPi1 > <pin created, in this case 1234> join
Note: to disconnect to the AP
p2p_remove_client <hw_address_for_p2p-wlan0-0 of the RPi1>
We need to check if we have a p2p-wlan0-0 interface created and with IP

Free HTML5 Template by FreeHTML5.coclient joining AP. p2p-wlan0-0 interface created OK

IF we have ip than everything is ok and, on the server side(RPI1) we can see the connected devices: 

$ sudo arp -a
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