Question about sending beacons

Jouni Malinen j
Sun Nov 30 07:55:11 PST 2008

On Sun, Nov 30, 2008 at 04:42:46PM +0200, Mark Ryden wrote:

>    I am new to hostapd;   I am using hostapd with nl80211.
> As far as I know, an Access Point should send something like 10
> beacons per second.
>   My question is: which method is called to send beacons ?  I want to
> delve into the code a bit.

hostapd generates the Beacon frame template (everything apart from TIM
IE) (see ieee802_11_set_beacon() in hostapd/beacon.c) and configures
that into mac80211 (in kernel). Furthermore, hostapd configures the
interval for Beacon frame transmission. The actual Beacon frame
construction (use the template and insert TIM IE) happens in mac80211
(see ieee80211_beacon_get() in Linux kernel net/mac80211/tx.c) and
actual transmission/scheduling at the drivers (search for
ieee80211_beacon_get calls in drivers/net/wireless/...).

Jouni Malinen                                            PGP id EFC895FA

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