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From ea0c3e2a470271573d480f48a67e74633566a317 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20L=C3=BCssing?= <ll@simonwunderlich.de>
Date: Fri, 15 Nov 2019 11:56:12 +0100
Subject: [PATCH] ath10k: fix RX of frames with broken FCS in monitor mode
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Git-commit: ea0c3e2a470271573d480f48a67e74633566a317
Patch-mainline: v5.6-rc1
References: jsc#SLE-13430

So far, frames were forwarded regardless of the FCS correctness leading
to userspace applications listening on the monitor mode interface to
receive potentially broken frames, even with the "fcsfail" flag unset.

By default, with the "fcsfail" flag of a monitor mode interface
unset, frames with FCS errors should be dropped. With this patch, the
fcsfail flag is taken into account correctly.

Tested-on: QCA4019 firmware-5-ct-full-community-12.bin-lede.011

Cc: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Linus Lüssing <ll@simonwunderlich.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/wireless/ath/ath10k/core.h   | 1 +
 drivers/net/wireless/ath/ath10k/debug.c  | 2 ++
 drivers/net/wireless/ath/ath10k/htt_rx.c | 7 +++++++
 3 files changed, 10 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
index c5407f5080b2..5101bf2b5b15 100644
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -1181,6 +1181,7 @@ struct ath10k {
 
 	struct {
 		/* protected by data_lock */
+		u32 rx_crc_err_drop;
 		u32 fw_crash_counter;
 		u32 fw_warm_reset_counter;
 		u32 fw_cold_reset_counter;
diff --git a/drivers/net/wireless/ath/ath10k/debug.c b/drivers/net/wireless/ath/ath10k/debug.c
index 04c50a26a4f4..e000677ac516 100644
--- a/drivers/net/wireless/ath/ath10k/debug.c
+++ b/drivers/net/wireless/ath/ath10k/debug.c
@@ -1094,6 +1094,7 @@ static const char ath10k_gstrings_stats[][ETH_GSTRING_LEN] = {
 	"d_rts_good",
 	"d_tx_power", /* in .5 dbM I think */
 	"d_rx_crc_err", /* fcs_bad */
+	"d_rx_crc_err_drop", /* frame with FCS error, dropped late in kernel */
 	"d_no_beacon",
 	"d_tx_mpdus_queued",
 	"d_tx_msdu_queued",
@@ -1193,6 +1194,7 @@ void ath10k_debug_get_et_stats(struct ieee80211_hw *hw,
 	data[i++] = pdev_stats->rts_good;
 	data[i++] = pdev_stats->chan_tx_power;
 	data[i++] = pdev_stats->fcs_bad;
+	data[i++] = ar->stats.rx_crc_err_drop;
 	data[i++] = pdev_stats->no_beacons;
 	data[i++] = pdev_stats->mpdu_enqued;
 	data[i++] = pdev_stats->msdu_enqued;
diff --git a/drivers/net/wireless/ath/ath10k/htt_rx.c b/drivers/net/wireless/ath/ath10k/htt_rx.c
index 0f1f71e43b9b..9faecfa5f9d7 100644
--- a/drivers/net/wireless/ath/ath10k/htt_rx.c
+++ b/drivers/net/wireless/ath/ath10k/htt_rx.c
@@ -1285,6 +1285,13 @@ static void ath10k_process_rx(struct ath10k *ar, struct sk_buff *skb)
 
 	status = IEEE80211_SKB_RXCB(skb);
 
+	if (!(ar->filter_flags & FIF_FCSFAIL) &&
+	    status->flag & RX_FLAG_FAILED_FCS_CRC) {
+		ar->stats.rx_crc_err_drop++;
+		dev_kfree_skb_any(skb);
+		return;
+	}
+
 	ath10k_dbg(ar, ATH10K_DBG_DATA,
 		   "rx skb %pK len %u peer %pM %s %s sn %u %s%s%s%s%s%s %srate_idx %u vht_nss %u freq %u band %u flag 0x%x fcs-err %i mic-err %i amsdu-more %i\n",
 		   skb,
-- 
2.16.4