From 3e5b1101f59fb3e17a8eb32cca100ae07fd7100e Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Sat, 14 Nov 2009 03:29:38 +0100
Subject: [PATCH] mac80211: reduce the amount of unnecessary traffic on cooked
 monitor interfaces

In order to handle association and authentication in AP mode,
hostapd needs access to the tx status info of its own frames
through a cooked monitor interface. Without this patch the
cooked monitor interfaces also passed on tx status information
for packets from other virtual interfaces. This creates a
significant performance issue on embedded system. Hostapd
tries to work around this by installing a Linux Socket Filter
that only captures the frames it's interested in, however
data duplication and socket filter matching still uses up
enough CPU cycles to be very noticeable on small systems.
This patch ensures that tx status information of non-injected
frames does not make it to cooked monitor interfaces.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
---
 net/mac80211/main.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index beb8718d905e..c74a6a1935b3 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -587,6 +587,11 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 			if (!netif_running(sdata->dev))
 				continue;
 
+			if ((sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) &&
+			    !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
+			    (type == IEEE80211_FTYPE_DATA))
+				continue;
+
 			if (prev_dev) {
 				skb2 = skb_clone(skb, GFP_ATOMIC);
 				if (skb2) {
-- 
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