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mac80211: add no update durationId bit in radiotap

PATCH New Marek Kwaczynski 2 participants 5 messages May 6, 2014

Subsystems (3)
mac80211 802.11 (including cfg80211/NL80211) Qualcomm Atheros ATH9K wireless driver
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Marek Kwaczynski

author
#0 lore raw

PATCH 1/2 mac80211: add no update durationId bit in radiotap

Adds a new bit in radiotap_tx flags, which allows injections frames without changing durationId filed. The intention is a NAV update testing.

Signed-off-by Marek Kwaczynski <[email protected]>
---
 include/net/ieee80211_radiotap.h |   14 +++++++++-----
 include/net/mac80211.h           |    3 +++
 net/mac80211/tx.c                |    4 ++++
 3 files changed, 16 insertions(+), 5 deletions(-)
include/net/ieee80211_radiotap.h +9 -5
index b0fd947..b00b7dd 100644
@@ -261,11 +261,15 @@ enum ieee80211_radiotap_type {
 
 /* For IEEE80211_RADIOTAP_TX_FLAGS */
 #define IEEE80211_RADIOTAP_F_TX_FAIL	0x0001	/* failed due to excessive
-						 * retries */
-#define IEEE80211_RADIOTAP_F_TX_CTS	0x0002	/* used cts 'protection' */
-#define IEEE80211_RADIOTAP_F_TX_RTS	0x0004	/* used rts/cts handshake */
-#define IEEE80211_RADIOTAP_F_TX_NOACK	0x0008	/* don't expect an ack */
-
+							 * retries */
+#define IEEE80211_RADIOTAP_F_TX_CTS		0x0002	/* used cts
+							 * 'protection' */
+#define IEEE80211_RADIOTAP_F_TX_RTS		0x0004	/* used rts/cts
+							 * handshake */
+#define IEEE80211_RADIOTAP_F_TX_NOACK		0x0008	/* don't expect an
+							 * ack */
+#define IEEE80211_RADIOTAP_F_TX_NO_DUR_UPDATE	0x0010  /* don't touch
+							 * durationId field */
 
 /* For IEEE80211_RADIOTAP_MCS */
 #define IEEE80211_RADIOTAP_MCS_HAVE_BW		0x01
include/net/mac80211.h +3 -0
index 2de7ff4..8c55eb9 100644
@@ -512,11 +512,14 @@ enum mac80211_tx_info_flags {
  *
  * @IEEE80211_TX_CTRL_PORT_CTRL_PROTO: this frame is a port control
  *	protocol frame (e.g. EAP)
+ * @IEEE80211_TX_CTRL_NO_DUR_UPDATE: This frame should be send without
+ *	changing durationID field.
  *
  * These flags are used in tx_info->control.flags.
  */
 enum mac80211_tx_control_flags {
 	IEEE80211_TX_CTRL_PORT_CTRL_PROTO	= BIT(0),
+	IEEE80211_TX_CTRL_NO_DUR_UPDATE		= BIT(1),
 };
 
 /*
net/mac80211/tx.c +4 -0
index 19d36d4..3b8087e 100644
@@ -104,6 +104,10 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx,
 		 *    and its SIFS
 		 * PS Poll: BIT(15) | BIT(14) | aid
 		 */
+		/* Don't touch durationId field */
+		if (info->flags & IEEE80211_TX_CTRL_NO_DUR_UPDATE)
+			return hdr->duration_id;
+
 		return 0;
 	}
Signature · 1 line
1.7.9.5
author
#1 lore raw

PATCH 2/2 ath9k: Handling flag IEEE80211_TX_CTRL_NO_DUR_UPDATE

Prevents durationId field updates for injected frames when this information is included in radiotap header. It could be very useful for testing NAV update.

Signed-off-by Marek Kwaczynski <[email protected]>
---
 drivers/net/wireless/ath/ath9k/xmit.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)
drivers/net/wireless/ath/ath9k/xmit.c +9 -2
index 87cbec4..c24c113 100644
@@ -1092,8 +1092,15 @@ static void ath_buf_set_rate(struct ath_softc *sc, struct ath_buf *bf,
 	rates = bf->rates;
 	hdr = (struct ieee80211_hdr *)skb->data;
 
-	/* set dur_update_en for l-sig computation except for PS-Poll frames */
-	info->dur_update = !ieee80211_is_pspoll(hdr->frame_control);
+	if (tx_info->flags & IEEE80211_TX_CTRL_NO_DUR_UPDATE) {
+		info->dur_update = 0;
+	} else {
+		/* set dur_update_en for l-sig computation except for PS-Poll
+		 * frames
+		 */
+		info->dur_update = !ieee80211_is_pspoll(hdr->frame_control);
+	}
+
 	info->rtscts_rate = fi->rtscts_rate;
 
 	for (i = 0; i < ARRAY_SIZE(bf->rates); i++) {
Signature · 1 line
1.7.9.5
maintainer NAK
#2 lore raw

PATCH 1/2 mac80211: add no update durationId bit in radiotap

In reply to Marek Kwaczynski
Quoted 3 lines · Marek Kwaczynski

Adds a new bit in radiotap_tx flags, which allows injections frames without changing durationId filed. The intention is a NAV update testing.

NACK.

http://www.radiotap.org/suggested-fields/TX%20flags

And since I'm tired of this, I'll make any further radiotap updates to this particular field contingent on somebody actually standardising it properly.

johannes

author
#3 lore raw

PATCH 1/2 mac80211: add no update durationId bit in radiotap

Hi Johannes,

I can achieve the same result without changing radiotap header if durationID filed won't be updated for all injected frames. What do you think about it?

Best regards,
Marek Kwaczynski

Quoted 15 lines · Johannes Berg
Quoted 3 lines · Marek Kwaczynski

Adds a new bit in radiotap_tx flags, which allows injections frames without changing durationId filed. The intention is a NAV update testing.

NACK.

http://www.radiotap.org/suggested-fields/TX%20flags

And since I'm tired of this, I'll make any further radiotap updates to this particular field contingent on somebody actually standardising it properly.

johannes

maintainer
#4 lore raw

PATCH 1/2 mac80211: add no update durationId bit in radiotap

Quoted 5 lines · Marek Kwaczynski

Hi Johannes,

I can achieve the same result without changing radiotap header if durationID filed won't be updated for all injected frames. What do you think about it?

I think that's a terrible idea, particularly backward compatibility with older hostapd versions.

johannes