1 files changed, 22 insertions, 6 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 8a948ca55d80..d87d3f1a2f94 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1015,7 +1015,8 @@ static void ieee80211_chswitch_timer(unsigned long data)
 
 static void
 ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
-                                 u64 timestamp, struct ieee802_11_elems *elems)
+                                 u64 timestamp, struct ieee802_11_elems *elems,
+                                 bool beacon)
 {
         struct ieee80211_local *local = sdata->local;
         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
@@ -1032,6 +1033,7 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
         struct cfg80211_chan_def new_vht_chandef = {};
         const struct ieee80211_sec_chan_offs_ie *sec_chan_offs;
         const struct ieee80211_wide_bw_chansw_ie *wide_bw_chansw_ie;
+        const struct ieee80211_ht_operation *ht_oper;
         int secondary_channel_offset = -1;
 
         ASSERT_MGD_MTX(ifmgd);
@@ -1048,11 +1050,14 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 
         sec_chan_offs = elems->sec_chan_offs;
         wide_bw_chansw_ie = elems->wide_bw_chansw_ie;
+        ht_oper = elems->ht_operation;
 
         if (ifmgd->flags & (IEEE80211_STA_DISABLE_HT |
                             IEEE80211_STA_DISABLE_40MHZ)) {
                 sec_chan_offs = NULL;
                 wide_bw_chansw_ie = NULL;
+                /* only used for bandwidth here */
+                ht_oper = NULL;
         }
 
         if (ifmgd->flags & IEEE80211_STA_DISABLE_VHT)
@@ -1094,10 +1099,20 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
                 return;
         }
 
-        if (sec_chan_offs) {
+        if (!beacon && 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 (!(ifmgd->flags & IEEE80211_STA_DISABLE_HT)) {
-                /* if HT is enabled and the IE not present, it's still 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).
+                 */
                 secondary_channel_offset = IEEE80211_HT_PARAM_CHA_SEC_NONE;
         }
 
@@ -2796,7 +2811,8 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
                 mutex_unlock(&local->iflist_mtx);
         }
 
-        ieee80211_sta_process_chanswitch(sdata, rx_status->mactime, elems);
+        ieee80211_sta_process_chanswitch(sdata, rx_status->mactime,
+                                         elems, true);
 
 }
 
@@ -3210,7 +3226,7 @@ void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 
                         ieee80211_sta_process_chanswitch(sdata,
                                                          rx_status->mactime,
-                                                         &elems);
+                                                         &elems, false);
                 } else if (mgmt->u.action.category == WLAN_CATEGORY_PUBLIC) {
                         ies_len = skb->len -
                                   offsetof(struct ieee80211_mgmt,
@@ -3232,7 +3248,7 @@ void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 
                         ieee80211_sta_process_chanswitch(sdata,
                                                          rx_status->mactime,
-                                                         &elems);
+                                                         &elems, false);
                 }
                 break;
         }