mac80211: ignore CSA to same channel

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 <johannes.berg@intel.com>

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index c0e089c194f1641762171402da195fe049bef06a..8d53d65bd2abc2d993ae5dbc7df37b707fd9ec13 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -464,6 +464,7 @@ 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 cde8cd3d65951c3fe88bd4b1643d7a46f1f979bc..142f66aece18a8789205fc12b0e1d7c7816d0863 100644 (file)
--- 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,
@@ -1210,6 +1221,7 @@ 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,
@@ -2090,6 +2102,7 @@ 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);