mac80211: protect non-HT BSS when HT TDLS traffic exists

HT TDLS traffic should be protected in a non-HT BSS to avoid
collisions. Therefore, when TDLS peers join/leave, check if
protection is (now) needed and set the ht_operation_mode of
the virtual interface according to the HT capabilities of the
TDLS peer(s).

This works because a non-HT BSS connection never sets (or
otherwise uses) the ht_operation_mode; it just means that
drivers must be aware that this field applies to all HT
traffic for this virtual interface, not just the traffic
within the BSS. Document that.

Signed-off-by: Avri Altman <avri.altman@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index e3314e516681ed0733ec212d7464c393222428ef..bfc569498bfa793013766e6e16158d29bb84c9ef 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -477,7 +477,9 @@ struct ieee80211_event {
  * @chandef: Channel definition for this BSS -- the hardware might be
  *     configured a higher bandwidth than this BSS uses, for example.
  * @ht_operation_mode: HT operation mode like in &struct ieee80211_ht_operation.
- *     This field is only valid when the channel type is one of the HT types.
+ *     This field is only valid when the channel is a wide HT/VHT channel.
+ *     Note that with TDLS this can be the case (channel is HT, protection must
+ *     be used from this field) even when the BSS association isn't using HT.
  * @cqm_rssi_thold: Connection quality monitor RSSI threshold, a zero value
  *     implies disabled
  * @cqm_rssi_hyst: Connection quality monitor RSSI hysteresis

diff --git a/net/mac80211/tdls.c b/net/mac80211/tdls.c
index aee701a5649e59ebd03ef300f25e33eadfc280d5..4e202d0679b26a0dfa0b89c5ae189f2ce7b56883 100644 (file)
--- a/net/mac80211/tdls.c
+++ b/net/mac80211/tdls.c
@@ -1249,6 +1249,58 @@ static void iee80211_tdls_recalc_chanctx(struct ieee80211_sub_if_data *sdata)
        mutex_unlock(&local->chanctx_mtx);
 }
 
+static int iee80211_tdls_have_ht_peers(struct ieee80211_sub_if_data *sdata)
+{
+       struct sta_info *sta;
+       bool result = false;
+
+       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) ||
+                   !test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH) ||
+                   !sta->sta.ht_cap.ht_supported)
+                       continue;
+               result = true;
+               break;
+       }
+       rcu_read_unlock();
+
+       return result;
+}
+
+static void
+iee80211_tdls_recalc_ht_protection(struct ieee80211_sub_if_data *sdata,
+                                  struct sta_info *sta)
+{
+       struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
+       bool tdls_ht;
+       u16 protection = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED |
+                        IEEE80211_HT_OP_MODE_NON_GF_STA_PRSNT |
+                        IEEE80211_HT_OP_MODE_NON_HT_STA_PRSNT;
+       u16 opmode;
+
+       /* Nothing to do if the BSS connection uses HT */
+       if (!(ifmgd->flags & IEEE80211_STA_DISABLE_HT))
+               return;
+
+       tdls_ht = (sta && sta->sta.ht_cap.ht_supported) ||
+                 iee80211_tdls_have_ht_peers(sdata);
+
+       opmode = sdata->vif.bss_conf.ht_operation_mode;
+
+       if (tdls_ht)
+               opmode |= protection;
+       else
+               opmode &= ~protection;
+
+       if (opmode == sdata->vif.bss_conf.ht_operation_mode)
+               return;
+
+       sdata->vif.bss_conf.ht_operation_mode = opmode;
+       ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_HT);
+}
+
 int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
                        const u8 *peer, enum nl80211_tdls_operation oper)
 {
@@ -1274,6 +1326,10 @@ int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
                return -ENOTSUPP;
        }
 
+       /* protect possible bss_conf changes and avoid concurrency in
+        * ieee80211_bss_info_change_notify()
+        */
+       sdata_lock(sdata);
        mutex_lock(&local->mtx);
        tdls_dbg(sdata, "TDLS oper %d peer %pM\n", oper, peer);
 
@@ -1287,16 +1343,18 @@ int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
 
                iee80211_tdls_recalc_chanctx(sdata);
 
-               rcu_read_lock();
+               mutex_lock(&local->sta_mtx);
                sta = sta_info_get(sdata, peer);
                if (!sta) {
-                       rcu_read_unlock();
+                       mutex_unlock(&local->sta_mtx);
                        ret = -ENOLINK;
                        break;
                }
 
+               iee80211_tdls_recalc_ht_protection(sdata, sta);
+
                set_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH);
-               rcu_read_unlock();
+               mutex_unlock(&local->sta_mtx);
 
                WARN_ON_ONCE(is_zero_ether_addr(sdata->u.mgd.tdls_peer) ||
                             !ether_addr_equal(sdata->u.mgd.tdls_peer, peer));
@@ -1318,6 +1376,11 @@ int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
                ieee80211_flush_queues(local, sdata, false);
 
                ret = sta_info_destroy_addr(sdata, peer);
+
+               mutex_lock(&local->sta_mtx);
+               iee80211_tdls_recalc_ht_protection(sdata, NULL);
+               mutex_unlock(&local->sta_mtx);
+
                iee80211_tdls_recalc_chanctx(sdata);
                break;
        default:
@@ -1335,6 +1398,7 @@ int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
                                     &sdata->u.mgd.request_smps_work);
 
        mutex_unlock(&local->mtx);
+       sdata_unlock(sdata);
        return ret;
 }