mac80211: add TDLS connection timeout

Adding a timeout for tearing down a TDLS connection that
hasn't had ACKed traffic sent through it for a certain
amount of time.

Since we have no other monitoring facility to indicate the
existance (or non-existance) of a peer, this patch will
cause a peer to be considered as unavailable if for some X
time at least some Y packets have all not been ACKed.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 20 insertions, 1 deletions

diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index 2800e1c65519..89290e33dafe 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -538,6 +538,8 @@ static void ieee80211_tx_latency_end_msrmnt(struct ieee80211_local *local,
  *  - current throughput (higher value for higher tpt)?
  */
 #define STA_LOST_PKT_THRESHOLD  50
+#define STA_LOST_TDLS_PKT_THRESHOLD     10
+#define STA_LOST_TDLS_PKT_TIME          (10*HZ) /* 10secs since last ACK */
 
 static void ieee80211_lost_packet(struct sta_info *sta, struct sk_buff *skb)
 {
@@ -548,7 +550,20 @@ static void ieee80211_lost_packet(struct sta_info *sta, struct sk_buff *skb)
             !(info->flags & IEEE80211_TX_STAT_AMPDU))
                 return;
 
-        if (++sta->lost_packets < STA_LOST_PKT_THRESHOLD)
+        sta->lost_packets++;
+        if (!sta->sta.tdls && sta->lost_packets < STA_LOST_PKT_THRESHOLD)
+                return;
+
+        /*
+         * If we're in TDLS mode, make sure that all STA_LOST_TDLS_PKT_THRESHOLD
+         * of the last packets were lost, and that no ACK was received in the
+         * last STA_LOST_TDLS_PKT_TIME ms, before triggering the CQM packet-loss
+         * mechanism.
+         */
+        if (sta->sta.tdls &&
+            (sta->lost_packets < STA_LOST_TDLS_PKT_THRESHOLD ||
+             time_before(jiffies,
+                         sta->last_tdls_pkt_time + STA_LOST_TDLS_PKT_TIME)))
                 return;
 
         cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
@@ -695,6 +710,10 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
                         if (info->flags & IEEE80211_TX_STAT_ACK) {
                                 if (sta->lost_packets)
                                         sta->lost_packets = 0;
+
+                                /* Track when last TDLS packet was ACKed */
+                                if (test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH))
+                                        sta->last_tdls_pkt_time = jiffies;
                         } else {
                                 ieee80211_lost_packet(sta, skb);
                         }