[PATCH 1/2] mac80211: document only injected *_RADIOTAP_* flags

[PATCH 1/2] mac80211: document only injected *_RADIOTAP_* flags

[Sven Eckelmann]

Not the internal flags but the radiotap flags are parsed when the monitor
injected frames are prepared for transmission. Thus the documentation
should only document these.

Reported-by: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Fixes: 5ec3aed9ba4c ("mac80211: Parse legacy and HT rate in injected frames")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 Documentation/networking/mac80211-injection.txt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/networking/mac80211-injection.txt b/Documentation/networking/mac80211-injection.txt
index ec8f934..0a459e4 100644
--- a/Documentation/networking/mac80211-injection.txt
+++ b/Documentation/networking/mac80211-injection.txt
@@ -37,8 +37,8 @@ radiotap headers and used to control injection:
    HT rate for the transmission (only for devices without own rate control).
    Also some flags are parsed
 
-   IEEE80211_TX_RC_SHORT_GI: use short guard interval
-   IEEE80211_TX_RC_40_MHZ_WIDTH: send in HT40 mode
+   IEEE80211_RADIOTAP_MCS_SGI: use short guard interval
+   IEEE80211_RADIOTAP_MCS_BW_40: send in HT40 mode
 
  * IEEE80211_RADIOTAP_DATA_RETRIES
 
-- 
2.7.0

[PATCH 2/2] mac80211: fix parsing of 40Mhz in injected radiotap header

[Sven Eckelmann]

The MCS bandwidth part of the radiotap header is 2 bits wide. The full 2
bit have to compared against IEEE80211_RADIOTAP_MCS_BW_40 and not only if
the first bit is set. Otherwise IEEE80211_RADIOTAP_MCS_BW_40 can be
confused with IEEE80211_RADIOTAP_MCS_BW_20U.

Fixes: 5ec3aed9ba4c ("mac80211: Parse legacy and HT rate in injected frames")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/mac80211/tx.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 3a7475f..60c26a5 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1691,7 +1691,7 @@ static bool ieee80211_parse_tx_radiotap(struct ieee80211_local *local,
 	bool rate_found = false;
 	u8 rate_retries = 0;
 	u16 rate_flags = 0;
-	u8 mcs_known, mcs_flags;
+	u8 mcs_known, mcs_flags, mcs_bw;
 	int i;
 
 	info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
@@ -1767,8 +1767,9 @@ static bool ieee80211_parse_tx_radiotap(struct ieee80211_local *local,
 			    mcs_flags & IEEE80211_RADIOTAP_MCS_SGI)
 				rate_flags |= IEEE80211_TX_RC_SHORT_GI;
 
+			mcs_bw = mcs_flags & IEEE80211_RADIOTAP_MCS_BW_MASK;
 			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_BW &&
-			    mcs_flags & IEEE80211_RADIOTAP_MCS_BW_40)
+			    mcs_bw == IEEE80211_RADIOTAP_MCS_BW_40)
 				rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
 			break;
 
-- 
2.7.0

Re: [PATCH 1/2] mac80211: document only injected *_RADIOTAP_* flags

[Johannes Berg]

On Wed, 2016-02-24 at 16:25 +0100, Sven Eckelmann wrote:
> Not the internal flags but the radiotap flags are parsed when the
> monitor
> injected frames are prepared for transmission. Thus the documentation
> should only document these.
> 
Both applied.

johannes