wil6210: drop Rx multicast packets that are looped-back to STA

Delivering a looped-back multicast packet to network stack can cause
higher layer protocols to fail like for example IPv6 DAD.
In STA mode, upon receiving Rx multicast packet, check if the source
MAC address is equal to our own MAC address and if so drop the packet.
Signed-off-by: Dedy Lansky <dlansky@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/wil6210/txrx.c

@@ -765,7 +765,14 @@ void wil_netif_rx_any(struct sk_buff *skb, struct net_device *ndev)
 		return;
 	}
 
-	if (wdev->iftype == NL80211_IFTYPE_AP && !vif->ap_isolate) {
+	if (wdev->iftype == NL80211_IFTYPE_STATION) {
+		if (mcast && ether_addr_equal(eth->h_source, ndev->dev_addr)) {
+			/* mcast packet looped back to us */
+			rc = GRO_DROP;
+			dev_kfree_skb(skb);
+			goto stats;
+		}
+	} else if (wdev->iftype == NL80211_IFTYPE_AP && !vif->ap_isolate) {
 		if (mcast) {
 			/* send multicast frames both to higher layers in
 			 * local net stack and back to the wireless medium