Subject: Re: [RFC PATCHv2 1/1] mac80211: Add support connection monitor in
 hardware
From: Johannes Berg <johannes@sipsolutions.net>
To: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Cc: linux-wireless@vger.kernel.org
In-Reply-To: <1268650643-23191-2-git-send-email-juuso.oikarinen@nokia.com>
References: <1268650643-23191-1-git-send-email-juuso.oikarinen@nokia.com>
	 <1268650643-23191-2-git-send-email-juuso.oikarinen@nokia.com>
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Date: Tue, 16 Mar 2010 14:45:35 -0700
Message-ID: <1268775935.8918.2.camel@jlt3.sipsolutions.net>
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Sender: linux-wireless-owner@vger.kernel.org

On Mon, 2010-03-15 at 12:57 +0200, Juuso Oikarinen wrote:
> This patch is based on a RFC patch by Kalle Valo.
> 
> The wl1271 has a feature which handles the connection monitor logic
> in hardware, basically sending periodically nullfunc frames and reporting
> to the host if AP is lost, after attempting to recover by sending
> probe-requests to the AP.
> 
> Add support to mac80211 by adding a new flag IEEE80211_HW_CONNECTION_MONITOR
> which prevents conn_mon_timer from triggering during idle periods, and
> prevents sending probe-requests to the AP if beacon-loss is indicated by the
> hardware.
> 
> Cc: Kalle Valo <kalle.valo@nokia.com>
> Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
> ---
>  include/net/mac80211.h |    4 ++++
>  net/mac80211/mlme.c    |   33 ++++++++++++++++++++++++++++++++-
>  2 files changed, 36 insertions(+), 1 deletions(-)
> 
> diff --git a/include/net/mac80211.h b/include/net/mac80211.h
> index 936bc41..cd7b471 100644
> --- a/include/net/mac80211.h
> +++ b/include/net/mac80211.h
> @@ -954,6 +954,9 @@ enum ieee80211_tkip_key_type {
>   *	Hardware can provide ack status reports of Tx frames to
>   *	the stack.
>   *
> + * @IEEE80211_HW_CONNECTION_MONITOR:
> + *      The hardware performs its own connection monitoring, including
> + *      periodic keep-alives to the AP and probing the AP on beacon loss.

I think this should mention that you get disconnected right away when
you then signal beacon loss with the mac80211 api call, which is new.
Might also be worth updating the API docs for that function.

> @@ -936,8 +939,36 @@ void ieee80211_beacon_loss_work(struct work_struct *work)
>  	struct ieee80211_sub_if_data *sdata =
>  		container_of(work, struct ieee80211_sub_if_data,
>  			     u.mgd.beacon_loss_work);
> +	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
> +	struct ieee80211_local *local = sdata->local;
> +	u8 bssid[ETH_ALEN];
> +
> +	if (!(sdata->local->hw.flags & IEEE80211_HW_CONNECTION_MONITOR))
> +		ieee80211_mgd_probe_ap(sdata, true);
> +	else {
> +		mutex_lock(&ifmgd->mtx);
> +		if (!ifmgd->associated) {
> +			mutex_unlock(&ifmgd->mtx);
> +			return;
> +		}
>  
> -	ieee80211_mgd_probe_ap(sdata, true);
> +		memcpy(bssid, ifmgd->associated->bssid, ETH_ALEN);
> +
> +		printk(KERN_DEBUG "No probe-response from AP %pM, "
> +		       "disconnected.\n", bssid);
> +
> +		ieee80211_set_disassoc(sdata);
> +		ieee80211_recalc_idle(local);
> +		mutex_unlock(&ifmgd->mtx);
> +		/*
> +		 * must be outside lock due to cfg80211,
> +		 * but that's not a problem.
> +		 */
> +		ieee80211_send_deauth_disassoc(sdata, bssid,
> +					       IEEE80211_STYPE_DEAUTH,
> +					       WLAN_REASON_DISASSOC_DUE_TO_INACTIVITY,
> +					       NULL);
> +	}

This !() is a little awkward, how about moving this to a new function?
and the message is also really misleading.

johannes