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>

1 files changed, 5 insertions, 3 deletions

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index aeb65b3d2295..aedbaaa067e6 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -872,13 +872,14 @@ void ieee80211_send_auth(struct ieee80211_sub_if_data *sdata,
 }
 
 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)
 {
         struct ieee80211_supported_band *sband;
         u8 *pos, *supp_rates_len, *esupp_rates_len = NULL;
         int i;
 
-        sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
+        sband = local->hw.wiphy->bands[band];
 
         pos = buffer;
 
@@ -966,7 +967,8 @@ void ieee80211_send_probe_req(struct ieee80211_sub_if_data *sdata, u8 *dst,
         memcpy(pos, ssid, ssid_len);
         pos += ssid_len;
 
-        skb_put(skb, ieee80211_build_preq_ies(local, pos, ie, ie_len));
+        skb_put(skb, ieee80211_build_preq_ies(local, pos, ie, ie_len,
+                                              local->hw.conf.channel->band));
 
         ieee80211_tx_skb(sdata, skb, 0);
 }