netdev - Re: [PATCH v2] mac80211: add assoc beacon timeout logic

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Date:	Mon, 11 Nov 2013 12:11:09 +0530
From:	Krishna Chaitanya <chaitanya.mgit@...il.com>
To:	Felipe Contreras <felipe.contreras@...il.com>
Cc:	linux-wireless <linux-wireless@...r.kernel.org>,
	netdev <netdev@...r.kernel.org>,
	"John W. Linville" <linville@...driver.com>,
	Johannes Berg <johannes@...solutions.net>,
	"David S. Miller" <davem@...emloft.net>
Subject: Re: [PATCH v2] mac80211: add assoc beacon timeout logic

On Mon, Nov 11, 2013 at 3:15 AM, Felipe Contreras
<felipe.contreras@...il.com> wrote:
> We don't want to be waiting forever for a beacon that will never come,
> just continue the association.
>
> Signed-off-by: Felipe Contreras <felipe.contreras@...il.com>
> ---
>
> The previous version depended on some cleanup patches, plus had some unclear
> rerun logic.
>
>  net/mac80211/ieee80211_i.h |  1 +
>  net/mac80211/mlme.c        | 32 ++++++++++++++++++++++++++------
>  2 files changed, 27 insertions(+), 6 deletions(-)
>
> diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
> index 611abfc..e1f858d 100644
> --- a/net/mac80211/ieee80211_i.h
> +++ b/net/mac80211/ieee80211_i.h
> @@ -358,6 +358,7 @@ struct ieee80211_mgd_assoc_data {
>         const u8 *supp_rates;
>
>         unsigned long timeout;
> +       unsigned long beacon_timeout;
>         int tries;
>
>         u16 capability;
> diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
> index 86e4ad5..68f76f7 100644
> --- a/net/mac80211/mlme.c
> +++ b/net/mac80211/mlme.c
> @@ -38,6 +38,7 @@
>  #define IEEE80211_ASSOC_TIMEOUT                (HZ / 5)
>  #define IEEE80211_ASSOC_TIMEOUT_LONG   (HZ / 2)
>  #define IEEE80211_ASSOC_TIMEOUT_SHORT  (HZ / 10)
> +#define IEEE80211_ASSOC_BEACON_TIMEOUT 2 * HZ

Don't you think its too long? 3-4 beacon intervals should suffice.

>  #define IEEE80211_ASSOC_MAX_TRIES      3
>
>  static int max_nullfunc_tries = 2;
> @@ -3475,6 +3476,24 @@ void ieee80211_mgd_conn_tx_status(struct ieee80211_sub_if_data *sdata,
>         ieee80211_queue_work(&local->hw, &sdata->work);
>  }
>
> +static int check_beacon(struct ieee80211_sub_if_data *sdata)
> +{
> +       struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
> +       struct ieee80211_mgd_assoc_data *assoc_data = ifmgd->assoc_data;
> +
> +       if (!assoc_data->need_beacon || ifmgd->have_beacon)
> +               return true;
> +
> +       if (time_after(jiffies, assoc_data->beacon_timeout)) {
> +               sdata_info(sdata, "no beacon from %pM\n", assoc_data->bss->bssid);
> +               return true;
> +       }
> +
> +       assoc_data->timeout = TU_TO_EXP_TIME(assoc_data->bss->beacon_interval);
> +       run_again(sdata, assoc_data->timeout);
> +       return false;
> +}
> +
>  void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata)
>  {
>         struct ieee80211_local *local = sdata->local;
> @@ -3533,12 +3552,12 @@ void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata)
>
>         if (ifmgd->assoc_data && ifmgd->assoc_data->timeout_started &&
>             time_after(jiffies, ifmgd->assoc_data->timeout)) {
> -               if ((ifmgd->assoc_data->need_beacon && !ifmgd->have_beacon) ||
> -                   ieee80211_do_assoc(sdata)) {
> -                       struct cfg80211_bss *bss = ifmgd->assoc_data->bss;
> -
> -                       ieee80211_destroy_assoc_data(sdata, false);
> -                       cfg80211_assoc_timeout(sdata->dev, bss);
> +               if (check_beacon(sdata)) {
> +                       if (ieee80211_do_assoc(sdata)) {
> +                               struct cfg80211_bss *bss = ifmgd->assoc_data->bss;
> +                               ieee80211_destroy_assoc_data(sdata, false);
> +                               cfg80211_assoc_timeout(sdata->dev, bss);
> +                       }
>                 }
>         } else if (ifmgd->assoc_data && ifmgd->assoc_data->timeout_started)
>                 run_again(sdata, ifmgd->assoc_data->timeout);
> @@ -4335,6 +4354,7 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
>                 sdata_info(sdata, "waiting for beacon from %pM\n",
>                            ifmgd->bssid);
>                 assoc_data->timeout = TU_TO_EXP_TIME(req->bss->beacon_interval);
> +               assoc_data->beacon_timeout = jiffies + IEEE80211_ASSOC_BEACON_TIMEOUT;
>                 assoc_data->timeout_started = true;
>                 assoc_data->need_beacon = true;
>         } else if (beacon_ies) {
> --
> 1.8.4.2+fc1
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