Thread (8 messages) 8 messages, 4 authors, 2013-10-28

Re: [PATCH 16/16] wl1251: Add sysfs file address for setting permanent mac address

From: Dan Williams <hidden>
Date: 2013-10-28 14:46:56
Also in: lkml, netdev

On Mon, 2013-10-28 at 15:00 +0100, Pali Rohár wrote:
On Monday 28 October 2013 14:55:22 Johannes Berg wrote:
quoted
On Mon, 2013-10-28 at 14:49 +0100, Pali Rohár wrote:
quoted
On Monday 28 October 2013 14:45:05 Johannes Berg wrote:
quoted
On Sat, 2013-10-26 at 22:34 +0200, Pali Rohár wrote:
quoted
Driver wl1251 generating mac address randomly at startup
and there is no way to set permanent mac address via
SET_IEEE80211_PERM_ADDR. This patch export sysfs file
which can set permanent mac address by userspace helper
program. Patch is needed for devices which do not store
mac address in internal wl1251 eeprom.
This doesn't really seem like a good idea since you can
also just use 'ip' or whatever to set the MAC address.

johannes
AFAIK you cannot set permanent address (show by ethtool -P
wlan0) via ip/ifconfig.
You probably can't, but that address also doesn't matter at
all and isn't really used anywhere.

johannes
There are some (proprietary) applications which using permanent 
address for something...

And also more important: some network managing tools using it. 
NetworkManager resetting current MAC address to permanent one 
before starting configuring interface.

So this will lead to never use correct MAC address (but random 
permanent one) assigned for that wl1251 wireless card...
If the device doesn't actually *have* a permanent MAC address, then it
shouldn't be returning one via ethtool, and should return an error for
ETHTOOL_GPERMADDR.  Setting the permanent MAC address shouldn't ever be
allowed except by the driver inspecting EEPROM, and certainly not via
sysfs.

mac80211 does have to do some special stuff due to virtual interfaces
and such, but in general, if the MAC address is randomly generated,
neither the driver nor mac80211 should be reporting that address as the
permanent address, only as the current one.

Dan

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