Re: [RFCv1] mac80211: Adds Software / Virtual AMP 80211

[Johannes Berg <johannes@sipsolutions.net>]

On 4/10/2012 2:20 PM, Johannes Berg wrote:
>>> I don't get this patch at all. Why am I reviewing some very very basic
>>> skeleton code when we should be discussing userspace APIs (we have
>>> already discussed them with a few people years ago), how the AMP is
>>> going to be managed, how the security handshake is going to work, etc.
>>
>> adding AMP (meaning Bluetooth Alternate MAC/PHY in case anybody cares)
>> for SoftMac WiFi cards should be done solely in kernel space between
>> Bluetooth core and mac80211. All the FullMac cards will expose the HCI
>> AMP directly via the Bluetooth core. See Marvell solution for example.
>>
>> If we require a userspace interaction, I think we are doing something
>> wrong here. And as far as I can tell, the only tricky part is the WPA2
>> PSK 4-way handshake. We would need a kernel implementation for that.
>
> You already know I disagree, I don't want this code re-implemented in
> kernel space when adding a few tightly controlled APIs is all it needs
> to use an existing implementation of the relevant mechanisms.

There are also additional complexities like wpa_supplicant having to 
know whether to set up/tear down a BT AMP interface for P2P concurrency 
etc., so it's not really a good idea anyway to implement it purely in 
kernel space and hope it'll all work out.

(My flight is boarding now so I can't elaborate or discuss right now.)

johannes