2 files changed, 7 insertions, 0 deletions

diff --git a/include/net/ieee80211.h b/include/net/ieee80211.h
index cb255432e4e4..e6af381e206d 100644
--- a/include/net/ieee80211.h
+++ b/include/net/ieee80211.h
@@ -1080,6 +1080,8 @@ struct ieee80211_device {
         int perfect_rssi;
         int worst_rssi;
 
+        u16 prev_seq_ctl;       /* used to drop duplicate frames */
+
         /* Callback functions */
         void (*set_security) (struct net_device * dev,
                               struct ieee80211_security * sec);
diff --git a/net/ieee80211/ieee80211_rx.c b/net/ieee80211/ieee80211_rx.c
index d9265195656d..ce28d571afac 100644
--- a/net/ieee80211/ieee80211_rx.c
+++ b/net/ieee80211/ieee80211_rx.c
@@ -478,6 +478,11 @@ int ieee80211_rx(struct ieee80211_device *ieee, struct sk_buff *skb,
                         goto rx_exit;
         }
 #endif
+        /* drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.29) */
+        if (sc == ieee->prev_seq_ctl)
+                goto rx_dropped;
+        else
+                ieee->prev_seq_ctl = sc;
 
         /* Data frame - extract src/dst addresses */
         if (skb->len < IEEE80211_3ADDR_LEN)