Fast connect after losing Link

[Naveen Singh]

On Wed, Feb 3, 2016 at 8:56 AM, Naveen Singh <naveen at nestlabs.com> wrote:
>
>
> On Wed, Feb 3, 2016 at 4:16 AM, Jouni Malinen <j at w1.fi> wrote:
>>
>> On Tue, Feb 02, 2016 at 11:56:09PM -0800, Naveen Singh wrote:
>> > Just after losing wifi link because of an incoming deauth with reason
>> > code 6 or 7, wpa_supplicant sets the fast_reconnect and
>> > fast_reconnect_ssid to current bss and current ssid.
>> >
>> > Later on  if fast_reconnect is not NULL it tries to connect to same
>> > SSID. This makes sense for some devices which does not use connman.
>> > Devices using wpa_supplicant with connman this connect is not useful
>> > at all as connman when it gets notified of this disconnect would
>> > disable the network that would end up causing a locally generated
>> > deauth and would nullify this connection attempt.
>>
>> Why would connman do something like that? Large number of enterprise APs
>> use Deauthentication frames to force load balancing and/or band
>> steering. Disabling the network profile immediately on a disconnection
>> event sounds like something that would result in pretty bad user
>> experience in such networks.
>
> Agreed. And we are seeing this.
>>
>>
>> > In stead of having this feature turned on all the time, it would be
>> > good to have a configuration from connman. Initialized value of this
>> > configuration would be turned on meaning fast connect is enabled and
>> > devices using connman along with wpa_supplicant would disable this
>> > feature.
>> >
>> > Does this make sense?
>>
>> If I understood the issue correctly, it sounds like the better direction
>> would be to modify connman..
>>
>> --
>> Jouni Malinen                                            PGP id EFC895FA
>>
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>
>
Hi Jouni
I was looking into the code for fast_connect from
wpa_supplicant_event_disassoc_finish and it looks like we try to
connect to same BSS. If it is trying to connect to same BSS how does
it helping us in solving band steering or load balancing problem. If
the connect request is invoked from wpas_select_network_from_last_scan
we may have a different BSSID and then I can understand it is trying
to connect to a different BSSID. Am I missing something here?

if (fast_reconnect) {
#ifndef CONFIG_NO_SCAN_PROCESSING
wpa_dbg(wpa_s, MSG_DEBUG, "Try to reconnect to the same BSS");
if (wpa_supplicant_connect(wpa_s, fast_reconnect,
  fast_reconnect_ssid) < 0) {
/* Recover through full scan */
wpa_supplicant_req_scan(wpa_s, 0, 100000);
}
#endif /* CONFIG_NO_SCAN_PROCESSING */
}

Regards
Naveen