[RFC] hostapd: DFS - handle running out of DFS channels

Zefir Kurtisi zefir.kurtisi at neratec.com
Mon Mar 7 02:02:39 PST 2016

On 03/07/2016 10:15 AM, Jouni Malinen wrote:
> On Fri, Oct 09, 2015 at 02:58:34PM +0200, Zefir Kurtisi wrote:
>> In scenarios where only DFS channels are available (e.g. outdoor,
>> special countrycodes), hostapd must be able to handle situations
>> where all are unavailable.
>> The two possibilities to get there are
>> 1) while operating on the last available DFS channel a radar is
>>    detected
>> 2) hostapd is started while all channels are unavailable
>> In both cases, hostapd instead of terminating should better
>> wait for the NOPs to pass and re-try operation after the CAC.
>> This patch attempts to provide this feature with minimal modifi-
>> cation of the existing DFS framework. It uses the condition
>> (iface->state == HAPD_IFACE_DFS && !iface->cac_started)
>> as NOP mode signature to retry operation from within
>> hostapd_dfs_nop_finished().
> I didn't see much comments on this (no objection; one supporting this).
> This was an "[RFC]" instead of "[PATCH]". Do you have an updated version
> of the patch or should this RFC version be applied as-is?
We have been using this modification (slightly updated) in our systems for half a
year now and it works as expected. I'll update the RFC and re-post it as patch.
While at that, I could add a dedicated state HAPD_IFACE_NOP instead of combining
state and cac_started as NOP indication. Would help readability a bit. Preference?

More information about the Hostap mailing list