mac80211: avoid spurious deauth frames/messages

With WEXT, it happens frequently that the SME
requests an authentication but then deauthenticates
right away because some new parameters came along.
Every time this happens we print a deauth message
and send a deauth frame, but both of that is rather
confusing. Avoid it by aborting the authentication
process silently, and telling cfg80211 about that.

The patch looks larger than it really is:
__cfg80211_auth_remove() is split out from
cfg80211_send_auth_timeout(), there's no new code
except __cfg80211_auth_canceled() (a one-liner) and
the mac80211 bits (7 new lines of code).

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index d1e05ae..a6492e9 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1839,6 +1839,18 @@
 void cfg80211_send_auth_timeout(struct net_device *dev, const u8 *addr);
 
 /**
+ * __cfg80211_auth_canceled - notify cfg80211 that authentication was canceled
+ * @dev: network device
+ * @addr: The MAC address of the device with which the authentication timed out
+ *
+ * When a pending authentication had no action yet, the driver may decide
+ * to not send a deauth frame, but in that case must calls this function
+ * to tell cfg80211 about this decision. It is only valid to call this
+ * function within the deauth() callback.
+ */
+void __cfg80211_auth_canceled(struct net_device *dev, const u8 *addr);
+
+/**
  * cfg80211_send_rx_assoc - notification of processed association
  * @dev: network device
  * @buf: (re)association response frame (header + body)