WiFi and changed MAC addrs
Subsystems (2)
I just spent basically a day of my weekend grappling with this problem http://wiki.xensource.com/xenwiki/XenWifi
before I understood it well enough to realize that the fact that Xen changed the MAC addr for my WiFi card was the root cause of the problem. This got me thinking:
If a particular piece of hardware will refuse to send frames after the MAC address has been changed, then shouldn't the card's driver refuse to allow a change of the MAC address and return an error in response to the IOCTL that tries to change it? I can't think of a situation where this wouldn't be the right thing to do. However, before I submit a patch to fix this, does anyone else know of any special cases that I might need to deal with?
Also is behavior of refusing to send frames with a non-hardware specified MAC address part of the WiFi spec or is it particular to certain WiFi cards? IOW at what level do I need to fix it? Should I just fix it for the Intel cards that I've tested or do I need to fix it for all WiFi cards?
-ben
Quoted 4 lines · Ben Woodard
If a particular piece of hardware will refuse to send frames after the MAC address has been changed, then shouldn't the card's driver refuse to allow a change of the MAC address and return an error in response to the IOCTL that tries to change it?
Yes.
Quoted 4 lines
I can't think of a situation where this
wouldn't be the right thing to do. However, before I submit a patch to fix this, does anyone else know of any special cases that I might need to deal with?
That wouldn't make sense now, would it?
Quoted 5 lines
Also is behavior of refusing to send frames with a non-hardware specified MAC address part of the WiFi spec or is it particular to certain WiFi cards? IOW at what level do I need to fix it? Should I just fix it for the Intel cards that I've tested or do I need to fix it for all WiFi cards?
Most wifi cards don't care at all what MAC address you send, in fact allowing you to send with various MAC addresses. So this is something intel specific. Oh are we talking about iwlwifi? If so, please report to their maintainers immediately, they're lazy bastards and don't even upload the new MAC address to the card even if they could.
johannes