Hello,
I'm having an issue where missed beacons are not causing an access point to
disconnect.
Here is my setup:
* Kernel 3.3 (Unfortunately I cannot change this)
* WPA Supplicant 2.5
* Wireless Extension 29
* RTL8192cu Device Driver
I've already done some debugging, and have found a possible issue in the kernel
(that I'm unsure how to solve at this point). Here is what my debugging has
revealed:
In the file: net/mac80211/scan.c line 214 I see a BSS with a bssid matching my
AP as being linked (with my cfg80211_registered_device I believe???) via the
function ieee80211_scan_rx. If I power off my AP, I no longer see this specific
BSS as being received, so the driver seems to be scanning correctly and
returning valid results.
After 15 seconds (IEEE80211_SCAN_RESULT_EXPIRE in net/wireless/scan.c) of
missing a beacon, I would expect this BSS to be unlinked at the end of the next
scan via cfg80211_wext_giwscan->ieee80211_scan_results->cfg80211_bss_expire.
However, in the function cfg80211_bss_expire, this particular BSS is not
unlinked, because line 205 asserts that the BSS atomic "lock" is being held (>1
value read).
Looking into why it is held, I believe that the BSS is held once we
authenticate at the MLME layer.
My question is, how do I get this BSS to be unheld (probably in the MLME layer)
so my AP is no longer linked - as it clearly should not be linked after being
powered off long enough?
Could this be an error in my wpa_supplicant.conf, or is it a kernel bug? To me
it seems like a kernel bug because the registered device still thinks that BSS
is being held.
I've tried a few things to get this to work correctly with wpa_supplicant, but
the only thing that I've done that has made the kernel give up on the current
BSS is:
# wpa_cli reassociate
which seems to make sense as that forces the registered device to give up its
current BSS.
I've also tried
# wpa_cli bss_expire_age 10
# wpa_cli bss_expire_count 2
Which is another user-space attempt at a solution, but I think the issue may be
deeper than that.
Thanks for your time and help
Austin
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