Unicast packets stop being transmitted to a particular station, under load, when WPA2 is enabled

[Avery Pennarun]

On Mon, May 12, 2014 at 1:05 AM, Ben Greear <greearb at candelatech.com> wrote:
> If it's getting on the air, then I think the only way to figure out
> what is wrong is to decode the packets and see if they are encrypted
> properly or not.  I think there is a way to get wireshark to decode
> pkts by feeding it the proper keys, but I have not ever actually tried
> doing that.

Okay, here is a fairly reduced capture of my wireshark trace:
http://apenwarr.ca/tmp/ath10k-utorrent-dropout-v2-reduced.pcapng.gz

To decode the wifi packets in wireshark, you need to follow these steps:
- open the pcap
- Edit | Preferences
- Protocols | IEEE 802.11
- Enable Decryption: checked
- Decryption Keys: Edit
- New
- Key type: wpa-pwd
- Key: my-password:my-ssid  (I'll email these to Ben privately; anyone
else interested, let me know)
- Ok
- Ok

The capture contains a lot of simultaneous TCP and UDP sessions, since
I can only trigger the problem when there is quite a bit of stuff
going on.  Luckily the air itself was relatively quiet so there isn't
too much noise other than my AP and laptop.

I believe I can narrow down the dropout to somewhere between rows
20035 and 20391.  20035 is a packet from a remote server that is ACKed
by my macbook.  20391 is a packet from the same remote server that is
*not* ACKed by my macbook, and then there are a bunch of retransmits
on that session after that.

I'm still looking at the capture to find any clues, but if anybody
else wants to take a peek, please do :)

Thanks,

Avery