On 09/20/2018 12:31 AM, Johannes Berg wrote:
On Wed, 2018-09-19 at 13:47 -0700, Ben Greear wrote:
For one, the driver has no concept of the original vif, since monitor
vifs aren't added to it.
ath10k does create a monitor vif, but maybe it is not mapped directly
to mac80211.
It's actually created by mac80211, but only once, and not directly
mapped to each vif seen by userspace - it's an internal construction.
I'm not sure it matters, but ath10k firmware can also create a monitor vdev
itself for certain reasons. (Maybe offchannel tx on some FW, but I haven't looked at
that code lately).
Secondly, the old hostapd code before nl80211 injects frames that way,
and they need to go there.
Ok, I agree we should not break backwards compat then. I'll poke some more
to see if I can get it working.
We might get away with doing this only for cooked monitor mode, which it
used there ...
However, thinking about it, that also breaks userspace in other ways -
for example if you do injection this way you actually get encryption and
other nice things if you use the local address that matches an existing
interface.
I'm not entirely sure of a useful use-case for this feature in user-space.
I am using it just to test sending some test frames to debug some firmware
features. I think another user sent hand-crafted specialized beacons in this manner
using my 10.1 ath10k firmware & driver. For whatever reason, I didn't realize monitor
vdevs were not directly used when I added that support..maybe I just got lucky
before I had to dig closely.
Perhaps you should just use a different address, and then nothing of the
sort would happen?
If I make the code in my original email be skipped, so that sdata remains the
monitor vdev, then it fails a check later in that method because there is no
chanctxt for the monitor sdata object.
I guess that changing the source MAC to something unique would cause the same
issue and no frame would be sent towards the driver.
Thanks,
Ben
johannes
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
