Wi-Fi Direct

Wi-Fi Direct is a wireless standard that allows devices to connect with each other without requiring a wireless access point. Wi-Fi Direct negotiates the link with a Wi-Fi Protected Setup (WPS) system that assigns each device a limited wireless access point.

Establishing a peer-to-peer (P2P) link has the following phases:

  • P2P discovery, which allows to search for P2P devices in the vicinity

  • P2P group formation, a P2P group is formed with the identification of one of the devices as group owner. A device can either become group owner (GO) autonomously if configured to do so or it can be negotiated between devices with the exchange of GO intents.

  • P2P provisioning, which authenticates the link by using either Push Button Configuration (PBC) or PIN authentication.

  • P2P connection, when the connection between a Group Owner (GO) and a Group Client (GC) is actually established.

The QCA6574 driver on load creates a p2p0 interface that is used by the wpa supplicant for P2P group formation. Once a group is formed, virtual {wifi-p2p-interface}N interfaces are created, where N is an index starting at 0. These virtual interfaces are then used for provisioning.

  • Group additions, find and connect operations happen on the p2p0 interface.

  • Provisioning occurs on the virtual {wifi-p2p-interface}N interfaces.

  • This configuration requires MAC addresses to be different and unique. Configure the virtual interfaces before attempting to connect more than one device.

By default, Digi Embedded Yocto configures the Wi-Fi Direct functionality by adding a p2p0 interface in /etc/network/interfaces. The interface is not automatically brought up.

The following instructions show how to configure the device to use Wi-Fi Direct.

  1. Delete the wlan1 interface to make sure we can assign a virtual MAC address to the interface {wifi-p2p-interface}0 that will be created. To delete the wlan1 interface, use the following command:

    ~# iw dev wlan1 del
  2. Bring up the p2p0 interface:

    ~# ifup p2p0

The following examples will use two ConnectCore 6UL devices to establish P2P connections. For more information about the wpa-supplicant P2P specific commands, see the wpa_supplicant and Wi-Fi P2P README.

Autonomous GO creation

In kernel v4.9, peer-to-peer Autonomous Group Owner (Autonomous GO) configuration fails due to an incompatibility in the wireless driver. Digi recommends you use the Negotiated Group Owner (Negotiated GO) method.

Create Autonomous Group Owner (GO) and join using PBC method

Peer (GO) ---- PBC --- Peer (GC)
Steps Peer CC6UL1 Peer CC6UL2

1

wpa_cli -ip2p0

wpa_cli -ip2p0

2

p2p_group_add

 

3

 

p2p_find

4

 

p2p_connect <CC6UL1_go_mac_addr> pbc join

5

Ctrl-c to exit

Ctrl-c to exit

6

wpa_cli -i {wifi-p2p-interface}0 wps_pbc

 

7

ifconfig {wifi-p2p-interface}0 <CC6UL1_ip_addr>

ifconfig {wifi-p2p-interface}0 <CC6UL2_ip_addr>

8

ping <CC6UL2_ip_addr>

ping <CC6UL1_ip_addr>

Create Autonomous GO and join using PIN from GO

Peer (GO) ---- PIN --- Peer (GC)
Steps Peer CC6UL1 Peer CC6UL2

1

wpa_cli -ip2p0

wpa_cli -ip2p0

2

p2p_group_add

 

3

 

p2p_find

4

Ctrl-c to exit

 

5

wpa_cli -i{wifi-p2p-interface}0 wps_pin any (shows <pin>)

 

6

 

p2p_connect <CC6UL1_go_mac_addr> <pin> join

7

 

Ctrl-c to exit

8

ifconfig {wifi-p2p-interface}0 <CC6UL1_ip_addr>

ifconfig {wifi-p2p-interface}0 <CC6UL2_ip_addr>

9

ping <CC6UL2_ip_addr>

ping <CC6UL1_ip_addr>

Create Autonomous GO and join using PIN from GC

Peer (GO) ---- PIN --- Peer (GC)
Steps Peer CC6UL1 Peer CC6UL2

1

wpa_cli -ip2p0

wpa_cli -ip2p0

2

p2p_group_add

 

3

 

p2p_find

4

 

p2p_connect <CC6UL1_go_mac_addr> pin join (shows <pin>)

5

Ctrl-c to exit

Ctrl-c to exit

6

wpa_cli -i{wifi-p2p-interface}0 wps_pin any <pin>

 

7

ifconfig {wifi-p2p-interface}0 <CC6UL1_ip_addr>

ifconfig {wifi-p2p-interface}0 <CC6UL2_ip_addr>

8

ping <CC6UL2_ip_addr>

ping <CC6UL1_ip_addr>

Create Autonomous GO and invite GC using PBC

Peer (GO) ---- PBC --- Peer (GC)
Steps Peer CC6UL1 Peer CC6UL2

1

wpa_cli -ip2p0

wpa_cli -ip2p0

2

p2p_group_add

 

3

 

p2p_find

4

p2p_invite group={wifi-p2p-interface}0 peer=<CC6UL2_mac_addr>

 

5

 

p2p_connect <CC6UL1_go_mac_addr> pbc join

6

Ctrl-c to exit

Ctrl-c to exit

7

wpa_cli -i {wifi-p2p-interface}0 wps_pbc

 

8

ifconfig {wifi-p2p-interface}0 <CC6UL1_ip_addr>

ifconfig {wifi-p2p-interface}0 <CC6UL2_ip_addr>

9

ping <CC6UL2_ip_addr>

ping <CC6UL1_ip_addr>

For any of these methods, if you want to use the 5GHz frequency, issue p2p_group_add freq=5180 in step two.

Negotiated GO

Negotiate GO and join using PIN

Peer (GO | GC) ---- PIN --- Peer (GO | GC)
Steps Peer CC6UL1 Peer CC6UL2

1

wpa_cli -ip2p0

wpa_cli -ip2p0

2

p2p_find

 

3

 

p2p_find

4

p2p_connect <CC6UL2_go_mac_addr> pin go_intent=1

 

5

 

p2p_connect <CC6UL1_go_mac_addr> <pin> go_intent=15

6

Ctrl-c to exit

Ctrl-c to exit

7

ifconfig {wifi-p2p-interface}0 <CC6UL1_ip_addr>

ifconfig {wifi-p2p-interface}0 <CC6UL2_ip_addr>

8

ping <CC6UL2_ip_addr>

ping <CC6UL1_ip_addr>

Negotiate GO and join using PBC

Peer (GO | GC) ---- PBC --- Peer (GO | GC)
Steps Peer CC6UL1 Peer CC6UL2

1

wpa_cli -ip2p0

wpa_cli -ip2p0

2

p2p_find

 

3

 

p2p_find

4

p2p_connect <CC6UL2_go_mac_addr> pbc go_intent=1

 

5

 

p2p_connect <CC6UL1_go_mac_addr> pbc go_intent=14

6

Ctrl-c to exit

Ctrl-c to exit

7

ifconfig {wifi-p2p-interface}0 <CC6UL1_ip_addr>

ifconfig {wifi-p2p-interface}0 <CC6UL2_ip_addr>

8

ping <CC6UL2_ip_addr>

ping <CC6UL1_ip_addr>