Re: [PATCH 001/002] [MAC80211] Retry probe request few times

[Johannes Berg <johannes@sipsolutions.net>]

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On Fri, 2009-07-31 at 19:14 +0300, Maxim Levitsky wrote:
> >From 0bf5749f2878f9245b8fb1b64456386374205225 Mon Sep 17 00:00:00 2001
> From: Maxim Levitsky <maximlevitsky@gmail.com>
> Date: Fri, 31 Jul 2009 18:54:12 +0300
> Subject: [PATCH] [MAC80211] Retry probe request few times
> 
> Retry 5 times  (chosen arbitary ), before assuming
> that station is out of range.
> 
> Fixes frequent disassociations while connected to weak,
> and sometimes even strong access points.

Looks good, thanks.

Acked-by: Johannes Berg <johannes@sipsolutions.net>

> Signed-off-by: Maxim Levitky <maximlevitsky@gmail.com>
> ---
>  net/mac80211/ieee80211_i.h |    1 +
>  net/mac80211/mlme.c        |   42 ++++++++++++++++++++++++++++++------------
>  2 files changed, 31 insertions(+), 12 deletions(-)
> 
> diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
> index aec6853..bca7b60 100644
> --- a/net/mac80211/ieee80211_i.h
> +++ b/net/mac80211/ieee80211_i.h
> @@ -280,6 +280,7 @@ struct ieee80211_if_managed {
>  	struct work_struct beacon_loss_work;
>  
>  	unsigned long probe_timeout;
> +	int probe_send_count;
>  
>  	struct mutex mtx;
>  	struct ieee80211_bss *associated;
> diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
> index ee83125..1d8640a 100644
> --- a/net/mac80211/mlme.c
> +++ b/net/mac80211/mlme.c
> @@ -31,6 +31,7 @@
>  #define IEEE80211_AUTH_MAX_TRIES 3
>  #define IEEE80211_ASSOC_TIMEOUT (HZ / 5)
>  #define IEEE80211_ASSOC_MAX_TRIES 3
> +#define IEEE80211_MAX_PROBE_TRIES 5
>  
>  /*
>   * beacon loss detection timeout
> @@ -1156,11 +1157,24 @@ void ieee80211_sta_rx_notify(struct ieee80211_sub_if_data *sdata,
>  		  round_jiffies_up(jiffies + IEEE80211_CONNECTION_IDLE_TIME));
>  }
>  
> +static void ieee80211_mgd_probe_ap_send(struct ieee80211_sub_if_data *sdata)
> +{
> +	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
> +	const u8 *ssid;
> +
> +	ssid = ieee80211_bss_get_ie(&ifmgd->associated->cbss, WLAN_EID_SSID);
> +	ieee80211_send_probe_req(sdata, ifmgd->associated->cbss.bssid,
> +				 ssid + 2, ssid[1], NULL, 0);
> +
> +	ifmgd->probe_send_count++;
> +	ifmgd->probe_timeout = jiffies + IEEE80211_PROBE_WAIT;
> +	run_again(ifmgd, ifmgd->probe_timeout);
> +}
> +
>  static void ieee80211_mgd_probe_ap(struct ieee80211_sub_if_data *sdata,
>  				   bool beacon)
>  {
>  	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
> -	const u8 *ssid;
>  	bool already = false;
>  
>  	if (!netif_running(sdata->dev))
> @@ -1203,18 +1217,12 @@ static void ieee80211_mgd_probe_ap(struct ieee80211_sub_if_data *sdata,
>  	if (already)
>  		goto out;
>  
> -	ifmgd->probe_timeout = jiffies + IEEE80211_PROBE_WAIT;
> -
>  	mutex_lock(&sdata->local->iflist_mtx);
>  	ieee80211_recalc_ps(sdata->local, -1);
>  	mutex_unlock(&sdata->local->iflist_mtx);
>  
> -	ssid = ieee80211_bss_get_ie(&ifmgd->associated->cbss, WLAN_EID_SSID);
> -	ieee80211_send_probe_req(sdata, ifmgd->associated->cbss.bssid,
> -				 ssid + 2, ssid[1], NULL, 0);
> -
> -	run_again(ifmgd, ifmgd->probe_timeout);
> -
> +	ifmgd->probe_send_count = 0;
> +	ieee80211_mgd_probe_ap_send(sdata);
>   out:
>  	mutex_unlock(&ifmgd->mtx);
>  }
> @@ -2072,17 +2080,27 @@ static void ieee80211_sta_work(struct work_struct *work)
>  	if (ifmgd->flags & (IEEE80211_STA_BEACON_POLL |
>  			    IEEE80211_STA_CONNECTION_POLL) &&
>  	    ifmgd->associated) {
> +		u8 bssid[ETH_ALEN];
> +
> +		memcpy(bssid, ifmgd->associated->cbss.bssid, ETH_ALEN);
>  		if (time_is_after_jiffies(ifmgd->probe_timeout))
>  			run_again(ifmgd, ifmgd->probe_timeout);
> -		else {
> -			u8 bssid[ETH_ALEN];
> +
> +		else if (ifmgd->probe_send_count < IEEE80211_MAX_PROBE_TRIES) {
> +#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
> +			printk(KERN_DEBUG "No probe response from AP %pM"
> +				" after %dms, try %d\n", bssid,
> +				(1000 * IEEE80211_PROBE_WAIT)/HZ,
> +				ifmgd->probe_send_count);
> +#endif
> +			ieee80211_mgd_probe_ap_send(sdata);
> +		} else {
>  			/*
>  			 * We actually lost the connection ... or did we?
>  			 * Let's make sure!
>  			 */
>  			ifmgd->flags &= ~(IEEE80211_STA_CONNECTION_POLL |
>  					  IEEE80211_STA_BEACON_POLL);
> -			memcpy(bssid, ifmgd->associated->cbss.bssid, ETH_ALEN);
>  			printk(KERN_DEBUG "No probe response from AP %pM"
>  				" after %dms, disconnecting.\n",
>  				bssid, (1000 * IEEE80211_PROBE_WAIT)/HZ);


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