tree 47fc3719a923afd23859c220ea548b97ac86a48e
parent 79df3b94e33d8254235ee4be1674a83abf1f3a89
author Jimmy Chen <jimmycmchen@google.com> 1542093597 +0800
committer Jimmy Chen <jimmycmchen@google.com> 1547521545 +0800

p2p: support random device address

To enhance privacy, generate a ramdom device address for p2p interface.
If there is no saved persistent group, it generate a new random MAC address on bringing up p2p0.
If there is saved persistent group, it will use last MAC address to avoid breaking
group reinvoke behavior.

There are two configurations are introduced:
* p2p_device_random_mac_addr
  enable device random MAC address feature, default disable.
* p2p_device_persistent_mac_addr
  store last used random MAC address.

Bug: 118904478
Test: manual test (Without saved persistent groups)
      * enable WiFi Direct in Settings.
      * check MAC address is changed on bringing up p2p0 everytime.
      * establish fresh connection between two peers.
      * establish reinvoke connection between two peers.
Test: manual test (With saved ersistent groups)
      * enable WiFi Direct in Settings.
      * ensure MAC address is restored to last used MAC address.
      * establish fresh connection between two peers.
      * establish reinvoke connection between two peers.
Test: CtsVerifier - WiFi Direct
      * Two random device address enabled device.
      * One random device address enabled device and
        One random device address disabled device.

Change-Id: I3a519209752e0e79c82c7fbd9c7a18669f778e84