From: Johannes Berg <[email protected]>

If the AP is confused and starts doing a CSA to the same channel,
just ignore that request instead of trying to act it out since it
was likely sent in error anyway.

In the case of the bug I was investigating the GO was misbehaving
and sending out a beacon with CSA IEs still included after having
actually done the channel switch.

Signed-off-by: Johannes Berg <[email protected]>
---
 net/mac80211/ieee80211_i.h |  1 +
 net/mac80211/mlme.c        | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 0266c57..994d1b3 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -453,6 +453,7 @@ struct ieee80211_if_managed {
        unsigned int flags;
 
        bool csa_waiting_bcn;
+       bool csa_ignored_same_chan;
 
        bool beacon_crc_valid;
        u32 beacon_crc;
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 1999bc0..6205206 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1150,6 +1150,17 @@ ieee80211_sta_process_chanswitch(struct 
ieee80211_sub_if_data *sdata,
                return;
        }
 
+       if (cfg80211_chandef_identical(&csa_ie.chandef,
+                                      &sdata->vif.bss_conf.chandef)) {
+               if (ifmgd->csa_ignored_same_chan)
+                       return;
+               sdata_info(sdata,
+                          "AP %pM tries to chanswitch to same channel, 
ignore\n",
+                          ifmgd->associated->bssid);
+               ifmgd->csa_ignored_same_chan = true;
+               return;
+       }
+
        mutex_lock(&local->mtx);
        mutex_lock(&local->chanctx_mtx);
        conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
@@ -1194,6 +1205,7 @@ ieee80211_sta_process_chanswitch(struct 
ieee80211_sub_if_data *sdata,
        sdata->vif.csa_active = true;
        sdata->csa_chandef = csa_ie.chandef;
        sdata->csa_block_tx = csa_ie.mode;
+       ifmgd->csa_ignored_same_chan = false;
 
        if (sdata->csa_block_tx)
                ieee80211_stop_vif_queues(local, sdata,
@@ -2076,6 +2088,7 @@ static void ieee80211_set_disassoc(struct 
ieee80211_sub_if_data *sdata,
 
        sdata->vif.csa_active = false;
        ifmgd->csa_waiting_bcn = false;
+       ifmgd->csa_ignored_same_chan = false;
        if (sdata->csa_block_tx) {
                ieee80211_wake_vif_queues(local, sdata,
                                          IEEE80211_QUEUE_STOP_REASON_CSA);
-- 
1.9.1

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