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Commit af88b907 authored by Helmut Schaa's avatar Helmut Schaa Committed by John W. Linville
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mac80211: handle failed scan requests in STA mode 



If cfg80211 requests a scan it awaits either a return code != 0 from
the scan function or the cfg80211_scan_done to be called. In case of
a STA mac80211's scan function ever returns 0 and queues the scan request.
If ieee80211_sta_work is executed and ieee80211_start_scan fails for
some reason cfg80211_scan_done will never be called but cfg80211 still
thinks the scan was triggered successfully and will refuse any future
scan requests due to drv->scan_req not being cleaned up.

If a scan is triggered from within the MLME a similar problem appears. If
ieee80211_start_scan returns an error, local->scan_req will not be reset
and mac80211 will refuse any future scan requests.

Hence, in both cases call ieee80211_scan_failed (which notifies cfg80211
and resets local->scan_req) if ieee80211_start_scan returns an error.

Signed-off-by: default avatarHelmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 8830cb67

net/mac80211/ieee80211_i.h

+1 −0
Original line number Diff line number Diff line
@@ -972,6 +972,7 @@ int ieee80211_sta_set_extra_ie(struct ieee80211_sub_if_data *sdata, 
			       char *ie, size_t len);



void ieee80211_mlme_notify_scan_completed(struct ieee80211_local *local);

void ieee80211_scan_failed(struct ieee80211_local *local);

int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,

			 struct cfg80211_scan_request *req);

struct ieee80211_bss *

net/mac80211/mlme.c

+12 −2
Original line number Diff line number Diff line
@@ -1720,7 +1720,10 @@ static int ieee80211_sta_config_auth(struct ieee80211_sub_if_data *sdata) 
				local->int_scan_req.ssids[0].ssid_len = 0;

			else

				local->int_scan_req.ssids[0].ssid_len = ifmgd->ssid_len;

			ieee80211_start_scan(sdata, &local->int_scan_req);



			if (ieee80211_start_scan(sdata, &local->int_scan_req))

				ieee80211_scan_failed(local);



			ifmgd->state = IEEE80211_STA_MLME_AUTHENTICATE;

			set_bit(IEEE80211_STA_REQ_AUTH, &ifmgd->request);

		} else {
@@ -1757,7 +1760,14 @@ static void ieee80211_sta_work(struct work_struct *work) 
	    ifmgd->state != IEEE80211_STA_MLME_AUTHENTICATE &&

	    ifmgd->state != IEEE80211_STA_MLME_ASSOCIATE &&

	    test_and_clear_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request)) {

		ieee80211_start_scan(sdata, local->scan_req);

		/*

		 * The call to ieee80211_start_scan can fail but ieee80211_request_scan

		 * (which queued ieee80211_sta_work) did not return an error. Thus, call

		 * ieee80211_scan_failed here if ieee80211_start_scan fails in order to

		 * notify the scan requester.

		 */

		if (ieee80211_start_scan(sdata, local->scan_req))

			ieee80211_scan_failed(local);

		return;

	}

net/mac80211/scan.c

+12 −0
Original line number Diff line number Diff line
@@ -202,6 +202,18 @@ ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb, 
	return RX_QUEUED;

}



void ieee80211_scan_failed(struct ieee80211_local *local)

{

	if (WARN_ON(!local->scan_req))

		return;



	/* notify cfg80211 about the failed scan */

	if (local->scan_req != &local->int_scan_req)

		cfg80211_scan_done(local->scan_req, true);



	local->scan_req = NULL;

}



void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)

{

	struct ieee80211_local *local = hw_to_local(hw);