mac80211: handle HT PHY BSS membership selector value correctly

802.11n-2009 extends the supported rates element with a
magic value which can be used to prevent legacy stations
from joining the BSS.

However, this magic value is not a rate like the others
and the magic can simply be ignored/skipped at this late
stage.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>---
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 49 insertions, 41 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index d3b408cda08d..b25567a32f92 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1466,6 +1466,47 @@ ieee80211_rx_mgmt_disassoc(struct ieee80211_sub_if_data *sdata,
         return RX_MGMT_CFG80211_DISASSOC;
 }
 
+static void ieee80211_get_rates(struct ieee80211_supported_band *sband,
+                                u8 *supp_rates, unsigned int supp_rates_len,
+                                u32 *rates, u32 *basic_rates,
+                                bool *have_higher_than_11mbit,
+                                int *min_rate, int *min_rate_index)
+{
+        int i, j;
+
+        for (i = 0; i < supp_rates_len; i++) {
+                int rate = (supp_rates[i] & 0x7f) * 5;
+                bool is_basic = !!(supp_rates[i] & 0x80);
+
+                if (rate > 110)
+                        *have_higher_than_11mbit = true;
+
+                /*
+                 * BSS_MEMBERSHIP_SELECTOR_HT_PHY is defined in 802.11n-2009
+                 * 7.3.2.2 as a magic value instead of a rate. Hence, skip it.
+                 *
+                 * Note: Even through the membership selector and the basic
+                 *       rate flag share the same bit, they are not exactly
+                 *       the same.
+                 */
+                if (!!(supp_rates[i] & 0x80) &&
+                    (supp_rates[i] & 0x7f) == BSS_MEMBERSHIP_SELECTOR_HT_PHY)
+                        continue;
+
+                for (j = 0; j < sband->n_bitrates; j++) {
+                        if (sband->bitrates[j].bitrate == rate) {
+                                *rates |= BIT(j);
+                                if (is_basic)
+                                        *basic_rates |= BIT(j);
+                                if (rate < *min_rate) {
+                                        *min_rate = rate;
+                                        *min_rate_index = j;
+                                }
+                                break;
+                        }
+                }
+        }
+}
 
 static bool ieee80211_assoc_success(struct ieee80211_work *wk,
                                     struct ieee80211_mgmt *mgmt, size_t len)
@@ -1482,7 +1523,7 @@ static bool ieee80211_assoc_success(struct ieee80211_work *wk,
         struct ieee802_11_elems elems;
         struct ieee80211_bss_conf *bss_conf = &sdata->vif.bss_conf;
         u32 changed = 0;
-        int i, j, err;
+        int err;
         bool have_higher_than_11mbit = false;
         u16 ap_ht_cap_flags;
         int min_rate = INT_MAX, min_rate_index = -1;
@@ -1540,47 +1581,14 @@ static bool ieee80211_assoc_success(struct ieee80211_work *wk,
         basic_rates = 0;
         sband = local->hw.wiphy->bands[wk->chan->band];
 
-        for (i = 0; i < elems.supp_rates_len; i++) {
-                int rate = (elems.supp_rates[i] & 0x7f) * 5;
-                bool is_basic = !!(elems.supp_rates[i] & 0x80);
-
-                if (rate > 110)
-                        have_higher_than_11mbit = true;
+        ieee80211_get_rates(sband, elems.supp_rates, elems.supp_rates_len,
+                            &rates, &basic_rates, &have_higher_than_11mbit,
+                            &min_rate, &min_rate_index);
 
-                for (j = 0; j < sband->n_bitrates; j++) {
-                        if (sband->bitrates[j].bitrate == rate) {
-                                rates |= BIT(j);
-                                if (is_basic)
-                                        basic_rates |= BIT(j);
-                                if (rate < min_rate) {
-                                        min_rate = rate;
-                                        min_rate_index = j;
-                                }
-                                break;
-                        }
-                }
-        }
-
-        for (i = 0; i < elems.ext_supp_rates_len; i++) {
-                int rate = (elems.ext_supp_rates[i] & 0x7f) * 5;
-                bool is_basic = !!(elems.ext_supp_rates[i] & 0x80);
-
-                if (rate > 110)
-                        have_higher_than_11mbit = true;
-
-                for (j = 0; j < sband->n_bitrates; j++) {
-                        if (sband->bitrates[j].bitrate == rate) {
-                                rates |= BIT(j);
-                                if (is_basic)
-                                        basic_rates |= BIT(j);
-                                if (rate < min_rate) {
-                                        min_rate = rate;
-                                        min_rate_index = j;
-                                }
-                                break;
-                        }
-                }
-        }
+        ieee80211_get_rates(sband, elems.ext_supp_rates,
+                            elems.ext_supp_rates_len, &rates, &basic_rates,
+                            &have_higher_than_11mbit,
+                            &min_rate, &min_rate_index);
 
         /*
          * some buggy APs don't advertise basic_rates. use the lowest