mac80211: split hardware scan by band

There's currently a very odd bug in mac80211 -- a
hardware scan that is done while the hardware is
really operating on 2.4 GHz will include CCK rates
in the probe request frame, even on 5 GHz (if the
driver uses the mac80211 IEs). Vice versa, if the
hardware is operating on 5 GHz the 2.4 GHz probe
requests will not include CCK rates even though
they should.

Fix this by splitting up cfg80211 scan requests by
band -- recalculating the IEs every time -- and
requesting only per-band scans from the driver.

Apparently this bug hasn't been a problem yet, but
it is imaginable that some older access points get
confused if confronted with such behaviour.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 60c2822..6365079 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -667,10 +667,9 @@
 	unsigned long scanning;
 	struct cfg80211_ssid scan_ssid;
 	struct cfg80211_scan_request *int_scan_req;
-	struct cfg80211_scan_request *scan_req;
+	struct cfg80211_scan_request *scan_req, *hw_scan_req;
 	struct ieee80211_channel *scan_channel;
-	const u8 *orig_ies;
-	int orig_ies_len;
+	enum ieee80211_band hw_scan_band;
 	int scan_channel_idx;
 	int scan_ies_len;
 
@@ -1050,7 +1049,8 @@
 			 u8 *extra, size_t extra_len, const u8 *bssid,
 			 const u8 *key, u8 key_len, u8 key_idx);
 int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
-			     const u8 *ie, size_t ie_len);
+			     const u8 *ie, size_t ie_len,
+			     enum ieee80211_band band);
 void ieee80211_send_probe_req(struct ieee80211_sub_if_data *sdata, u8 *dst,
 			      const u8 *ssid, size_t ssid_len,
 			      const u8 *ie, size_t ie_len);