[PATCH 3.17 059/141] mac80211: use secondary channel offset IE also beacons during CSA

[Greg Kroah-Hartman]

3.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Luciano Coelho <luciano.coelho@xxxxxxxxx>

commit 84469a45a1bedec9918e94ab2f78c5dc0739e4a7 upstream.

If we are switching from an HT40+ to an HT40- channel (or vice-versa),
we need the secondary channel offset IE to specify what is the
post-CSA offset to be used.  This applies both to beacons and to probe
responses.

In ieee80211_parse_ch_switch_ie() we were ignoring this IE from
beacons and using the *current* HT information IE instead.  This was
causing us to use the same offset as before the switch.

Fix that by using the secondary channel offset IE also for beacons and
don't ever use the pre-switch offset.  Additionally, remove the
"beacon" argument from ieee80211_parse_ch_switch_ie(), since it's not
needed anymore.

Reported-by: Jouni Malinen <j@xxxxx>
Signed-off-by: Luciano Coelho <luciano.coelho@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/mac80211/ibss.c        |    2 +-
 net/mac80211/ieee80211_i.h |    3 +--
 net/mac80211/mesh.c        |    2 +-
 net/mac80211/mlme.c        |    2 +-
 net/mac80211/spectmgmt.c   |   18 ++++++------------
 5 files changed, 10 insertions(+), 17 deletions(-)

--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -804,7 +804,7 @@ ieee80211_ibss_process_chanswitch(struct
 
 	memset(&params, 0, sizeof(params));
 	memset(&csa_ie, 0, sizeof(csa_ie));
-	err = ieee80211_parse_ch_switch_ie(sdata, elems, beacon,
+	err = ieee80211_parse_ch_switch_ie(sdata, elems,
 					   ifibss->chandef.chan->band,
 					   sta_flags, ifibss->bssid, &csa_ie);
 	/* can't switch to destination channel, fail */
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1639,7 +1639,6 @@ void ieee80211_process_measurement_req(s
  * ieee80211_parse_ch_switch_ie - parses channel switch IEs
  * @sdata: the sdata of the interface which has received the frame
  * @elems: parsed 802.11 elements received with the frame
- * @beacon: indicates if the frame was a beacon or probe response
  * @current_band: indicates the current band
  * @sta_flags: contains information about own capabilities and restrictions
  *	to decide which channel switch announcements can be accepted. Only the
@@ -1653,7 +1652,7 @@ void ieee80211_process_measurement_req(s
  * Return: 0 on success, <0 on error and >0 if there is nothing to parse.
  */
 int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,
-				 struct ieee802_11_elems *elems, bool beacon,
+				 struct ieee802_11_elems *elems,
 				 enum ieee80211_band current_band,
 				 u32 sta_flags, u8 *bssid,
 				 struct ieee80211_csa_ie *csa_ie);
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -874,7 +874,7 @@ ieee80211_mesh_process_chnswitch(struct
 
 	memset(&params, 0, sizeof(params));
 	memset(&csa_ie, 0, sizeof(csa_ie));
-	err = ieee80211_parse_ch_switch_ie(sdata, elems, beacon, band,
+	err = ieee80211_parse_ch_switch_ie(sdata, elems, band,
 					   sta_flags, sdata->vif.addr,
 					   &csa_ie);
 	if (err < 0)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1058,7 +1058,7 @@ ieee80211_sta_process_chanswitch(struct
 
 	current_band = cbss->channel->band;
 	memset(&csa_ie, 0, sizeof(csa_ie));
-	res = ieee80211_parse_ch_switch_ie(sdata, elems, beacon, current_band,
+	res = ieee80211_parse_ch_switch_ie(sdata, elems, current_band,
 					   ifmgd->flags,
 					   ifmgd->associated->bssid, &csa_ie);
 	if (res	< 0)
--- a/net/mac80211/spectmgmt.c
+++ b/net/mac80211/spectmgmt.c
@@ -22,7 +22,7 @@
 #include "wme.h"
 
 int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,
-				 struct ieee802_11_elems *elems, bool beacon,
+				 struct ieee802_11_elems *elems,
 				 enum ieee80211_band current_band,
 				 u32 sta_flags, u8 *bssid,
 				 struct ieee80211_csa_ie *csa_ie)
@@ -91,19 +91,13 @@ int ieee80211_parse_ch_switch_ie(struct
 		return -EINVAL;
 	}
 
-	if (!beacon && sec_chan_offs) {
+	if (sec_chan_offs) {
 		secondary_channel_offset = sec_chan_offs->sec_chan_offs;
-	} else if (beacon && ht_oper) {
-		secondary_channel_offset =
-			ht_oper->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET;
 	} else if (!(sta_flags & IEEE80211_STA_DISABLE_HT)) {
-		/* If it's not a beacon, HT is enabled and the IE not present,
-		 * it's 20 MHz, 802.11-2012 8.5.2.6:
-		 *	This element [the Secondary Channel Offset Element] is
-		 *	present when switching to a 40 MHz channel. It may be
-		 *	present when switching to a 20 MHz channel (in which
-		 *	case the secondary channel offset is set to SCN).
-		 */
+		/* If the secondary channel offset IE is not present,
+		 * we can't know what's the post-CSA offset, so the
+		 * best we can do is use 20MHz.
+		*/
 		secondary_channel_offset = IEEE80211_HT_PARAM_CHA_SEC_NONE;
 	}
 


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