mac80211: disconnect TDLS stations on STA CSA

When a station does a channel switch, it's not well defined what its TDLS
peers would do. Avoid a situation when the local side marks a potentially
disconnected peer as a TDLS peer.
Keeping peers connected through CSA is doubly problematic with the upcoming
TDLS WIDER-BW feature which allows peers to widen the BSS channel. The
new channel transitioned-to might not be compatible and would require
a re-negotiation anyway.

Make sure to disallow new TDLS link during CSA.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 3294666..387fe70 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1098,6 +1098,24 @@ static void ieee80211_chswitch_timer(unsigned long data)
        ieee80211_queue_work(&sdata->local->hw, &sdata->u.mgd.chswitch_work);
 }
 
+static void ieee80211_teardown_tdls_peers(struct ieee80211_sub_if_data *sdata)
+{
+       struct sta_info *sta;
+       u16 reason = WLAN_REASON_TDLS_TEARDOWN_UNSPECIFIED;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(sta, &sdata->local->sta_list, list) {
+               if (!sta->sta.tdls || sta->sdata != sdata || !sta->uploaded ||
+                   !test_sta_flag(sta, WLAN_STA_AUTHORIZED))
+                       continue;
+
+               ieee80211_tdls_oper_request(&sdata->vif, sta->sta.addr,
+                                           NL80211_TDLS_TEARDOWN, reason,
+                                           GFP_ATOMIC);
+       }
+       rcu_read_unlock();
+}
+
 static void
 ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
                                 u64 timestamp, u32 device_timestamp,
@@ -1161,6 +1179,14 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
                return;
        }
 
+       /*
+        * Drop all TDLS peers - either we disconnect or move to a different
+        * channel from this point on. There's no telling what our peer will do.
+        * The TDLS WIDER_BW scenario is also problematic, as peers might now
+        * have an incompatible wider chandef.
+        */
+       ieee80211_teardown_tdls_peers(sdata);
+
        mutex_lock(&local->mtx);
        mutex_lock(&local->chanctx_mtx);
        conf = rcu_dereference_protected(sdata->vif.chanctx_conf,

diff --git a/net/mac80211/tdls.c b/net/mac80211/tdls.c
index 8a92a92..75e8e3b 100644 (file)
--- a/net/mac80211/tdls.c
+++ b/net/mac80211/tdls.c
@@ -1183,6 +1183,12 @@ int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
 
        switch (oper) {
        case NL80211_TDLS_ENABLE_LINK:
+               if (sdata->vif.csa_active) {
+                       tdls_dbg(sdata, "TDLS: disallow link during CSA\n");
+                       ret = -EBUSY;
+                       break;
+               }
+
                rcu_read_lock();
                sta = sta_info_get(sdata, peer);
                if (!sta) {