Re: [zd1211-devs] zd1211rw progress

2006-05-16 Thread Daniel Drake

Remco wrote:

Are you saying that softmac does the association on behalf of wpa_supplicant ?


Yes - wpa_supplicant doesn't really have much say in the process. All it 
does is use WE to request association, and transmit and receive data 
frames, as well as set the encryption parameters once those have been 
negociated.



I'd expect something like this:
- softmac does authentication and association for open / shared, unencrypted / 
WEP encrypted networks.
- With WPA involved I expect softmac to authenticate, but since the 
association is different I expect wpa_supplicant to associate and inform 
softmac to update its association state once wpa_supplicant is done.


I don't know enough about WPA to say for sure, but I don't think the 
association is any different. The association definitely happens through 
the standard WE interface. The MLME is implemented fully in the kernel, 
and although it will be pushed out to userspace at some point, thats not 
the case just yet.


I think the way it works is like WEP: You can associate openly, but 
thats where the line is drawn, you are effectively useless on the 
network unless you are able to understand the encryption challenges 
which happen next, and eventually you end up with an encryption key 
which you use to decrypt all future data frames.


By just looking at the logs it seems either softmac associates on behalf of 
wpa_supplicant not giving wpa_supplicant a chance to do its thing or 
wpa_supplicant fails to do its thing and doesn't report failure to softmac 
leaving softmac to belief we've got an association.


I think the channel cycle after initial association causes the driver to 
miss the WPA challenge traffic. I can reproduce this here, if I do not 
load the appropriate encryption modules (the access point 
deauthenticates us, but the driver is too busy on other channels to see 
that happen). That's my best guess at your problem right now - I don't 
know if its the actual cause or not, but I'm not able to investigate 
further until I can get it working flawlessly for myself.


The softmac automatically scans / associates thing feels bad to me. It gives 
me the feeling wpa_supplicant is left out of the equation at some point.


I don't fully understand it, but I think this is a limitation of WE, 
because it doesn't even have a loose form of atomic association 
requests. When the initial association ioctl happens, softmac is not 
aware if wpa_supplicant will feed more specific details on the request 
after, so it just starts associating right away. We are discussing this 
on the linux-netdev list.


Also the associate once / associate again feels bad, I thought association is 
necessary only once.


Correct, this is softmac getting confused... The WE interface is hard to 
implement perfectly in softmacs current model, I haven't figured out how 
we're going to be able to support it better just yet.


Daniel


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Re: [zd1211-devs] monitor mode and malformed packets

2006-05-16 Thread Uli Kunitz
cees-bart wrote:

Hi,

the zd1211rw supports Monitor mode too. I'm not sure, what you
call malformed packets. The zd1211rw reassembles or splits
packets, which are split or combined for transport over the ZD1211
interface, I believe the vendor driver does the same. I've not
looked into packet injection, but it shouldn't be to difficult to
implement and test it.

However packets are shown as they are transmitted over the Air
including fragmented packets. The problem is, that ethereal seems
to have an issue to display fragments and lacks the
functionality to reassemble them. The other option would be, that
the driver does the reassembly, but then it doesn't make sense to
show 802.11 control frames (ACK, etc.).

Uli

-- 
Uli Kunitz - [EMAIL PROTECTED]


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