From b331615722779b078822988843ddffd4eaec9f83 Mon Sep 17 00:00:00 2001
From: "John W. Linville" <linville@tuxdriver.com>
Date: Tue, 28 Aug 2007 17:01:55 -0400
Subject: [PATCH] [MAC80211]: filter locally-originated multicast frames

In STA mode, the AP will echo our traffic.  This includes multicast
traffic.

Receiving these frames confuses some protocols and applications,
notably IPv6 Duplicate Address Detection.

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/mac80211/rx.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index e2c6f5cd1cf7..969be3adda7a 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -988,9 +988,10 @@ ieee80211_rx_h_data(struct ieee80211_txrx_data *rx)
 		memcpy(dst, hdr->addr1, ETH_ALEN);
 		memcpy(src, hdr->addr3, ETH_ALEN);
 
-		if (sdata->type != IEEE80211_IF_TYPE_STA) {
+		if (sdata->type != IEEE80211_IF_TYPE_STA ||
+		    (is_multicast_ether_addr(dst) &&
+		     !compare_ether_addr(src, dev->dev_addr)))
 			return TXRX_DROP;
-		}
 		break;
 	case 0:
 		/* DA SA BSSID */
-- 
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