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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: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Helmut Schaa 2009-03-09 15:47:08 +01:00 committed by John W. Linville
parent 8830cb678b
commit af88b9078d
3 changed files with 25 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
net/mac80211/ieee80211_i.h
View File

@ -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 *

14
net/mac80211/mlme.c
View File

@ -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;
}

12
net/mac80211/scan.c
View File

@ -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);