[PATCH] mac80211: improved 802.11g CTS protection

Currently, CTS protection is partially implemented twice:
 1. via prism2 ioctls, only used by hostapd
 2. via STA beacon parsing, recorded in sta.use_protection but never used
    (other than printed in debugfs)

Protection control should be implemented on a per-subif basis. For example,
a single physical device may be running a soft AP on one channel, and a STA
on another. The AP interface should use protection based on what hostapd told
it, and the STA interface should use protection based on beacon parsing.
These should operate independantly: one subif using protection should not
influence the other.

To implement this, I moved the use_protection flag into ieee80211_sub_if_data
and removed the device-global cts_protect_erp_frames flag.

I also made the PRISM2_PARAM_CTS_PROTECT_ERP_FRAMES write operation only
available for AP interfaces, to avoid any possibility of the user messing with
the behaviour of a STA.

Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index fe32a2d16053..2ddf4ef4065e 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -442,7 +442,7 @@ ieee80211_tx_h_rate_ctrl(struct ieee80211_txrx_data *tx)
         if (!tx->u.tx.rate)
                 return TXRX_DROP;
         if (tx->u.tx.mode->mode == MODE_IEEE80211G &&
-            tx->local->cts_protect_erp_frames && tx->fragmented &&
+            tx->sdata->use_protection && tx->fragmented &&
             extra.nonerp) {
                 tx->u.tx.last_frag_rate = tx->u.tx.rate;
                 tx->u.tx.probe_last_frag = extra.probe ? 1 : 0;
@@ -868,8 +868,7 @@ ieee80211_tx_h_misc(struct ieee80211_txrx_data *tx)
          * for the frame. */
         if (mode->mode == MODE_IEEE80211G &&
             (tx->u.tx.rate->flags & IEEE80211_RATE_ERP) &&
-            tx->u.tx.unicast &&
-            tx->local->cts_protect_erp_frames &&
+            tx->u.tx.unicast && tx->sdata->use_protection &&
             !(control->flags & IEEE80211_TXCTL_USE_RTS_CTS))
                 control->flags |= IEEE80211_TXCTL_USE_CTS_PROTECT;