mac80211: Decouple fail_avg stats used by mesh from rate control algorithm.

Mesh uses the tx failure average to compute the (m)path metric.  This used to
be done inside the rate control module.  This patch breaks the dependency
between the mesh stack and the rate control algorithm.  Mesh will now work
independently of the chosen rate control algorithm.

The mesh stack keeps a moving average of the average transmission losses for
each mesh peer station.  If the fail average exceeds a certain threshold, the
peer link is marked as broken.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index ef1efd362691..7aeba00ac502 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -201,6 +201,24 @@ int mesh_path_error_tx(u8 *dst, __le32 dst_dsn, u8 *ra,
         return 0;
 }
 
+void ieee80211s_update_metric(struct ieee80211_local *local,
+                struct sta_info *stainfo, struct sk_buff *skb)
+{
+        struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
+        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+        int failed;
+
+        if (!ieee80211_is_data(hdr->frame_control))
+                return;
+
+        failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
+
+        /* moving average, scaled to 100 */
+        stainfo->fail_avg = ((80 * stainfo->fail_avg + 5) / 100 + 20 * failed);
+        if (stainfo->fail_avg > 95)
+                mesh_plink_broken(stainfo);
+}
+
 static u32 airtime_link_metric_get(struct ieee80211_local *local,
                                    struct sta_info *sta)
 {