Hi,
as additional information to the already posted problem, I tested the
following settings:
p2p_device_random_mac_addr=1
p2p_device_persistent_mac_addr=dc:a6:32:01:02:03
The following call fails in driver_nl80211.c:
if (linux_set_iface_flags(drv->global->ioctl_sock, bss->ifname, 0) < 0)
This is the log:
...
Using existing control interface directory.
ctrl_interface_group=109 (from group name 'netdev')
p2p-dev-wlan0: Restore last used MAC address.
Could not read interface p2p-dev-wlan0 flags: No such device
p2p-dev-wlan0: Failed to set random MAC address
p2p-dev-wlan0: Failed to initialize P2P random MAC address.
p2p-dev-wlan0: Failed to init P2P
Failed to add interface p2p-dev-wlan0
...
Might it be related to some driver limitation?
I tested that, by setting the following code in "driver_nl80211.c"
before "ret = send_and_recv_msgs(drv, msg, handler, arg, NULL, NULL);"
the address can be forced to a predefined value:
#define STATIC_MAC_ADDRESS "dc:a6:32:01:02:03"
if (iftype == NL80211_IFTYPE_P2P_DEVICE) {
u8 mac_addr[ETH_ALEN];
if (hwaddr_aton2(STATIC_MAC_ADDRESS, mac_addr))
if(nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, mac_addr))
goto fail;
}
Would this be an appropriate strategy (e.g., sending STATIC_MAC_ADDRESS
by reading it from p2p_device_persistent_mac_addr)?
Thanks
Regards
Alberto
Il 29/12/2020 16:19, Macrì Alberto ha scritto:
The current versions of the nl80211 device drivers enable MAC
randomization by default, so that, when wpa_supplicant creates the
"P2P-Device" virtual interface, a randomized MAC address is used and
this breaks the persistent P2P Group reuse when the "P2P-Device"
virtual interface is recreated. A persistent P2P-GO group works
correctly while wpa_supplicant is running. After restarting
wpa_supplicant, it creates a new "P2P-device type" interface with a
different (randomized) MAC address and the saved persistent group in
the peer device becomes no more usable for reconnection: only a new
persistent group can be established (through new authorization
process), usable until wpa_supplicant is subsequently restarted.
The expected behaviour is that a reconnection to the previously saved
group is possible also after restarting wpa_supplicant.
After experimenting a modification in wpa_supplicant so that it forces
a fixed MAC address during the "P2P-Device" virtual interface
creation, I performed some tests using an Android device as P2P Client
and a Linux server running the modified wpa_supplicant: in such case
the issue is overcome.
Can someone confirm that a change has to be done in wpa_supplicant in
order to support such feature?
Thanks
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