802.11: clean up/fix HT support

This patch cleans up a number of things:
 * the unusable definition of the HT capabilities/HT information
   information elements
 * variable names that are hard to understand
 * mac80211: move ieee80211_handle_ht to ht.c and remove the unused
             enable_ht parameter
 * mac80211: fix bug with MCS rate 32 in ieee80211_handle_ht
 * mac80211: fix bug with casting the result of ieee80211_bss_get_ie
             to an information element _contents_ rather than the
             whole element, add size checking (another out-of-bounds
             access bug fixed!)
 * mac80211: remove some unused return values in favour of BUG_ON
             checking
 * a few minor other things

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 129 insertions, 22 deletions

diff --git a/net/mac80211/ht.c b/net/mac80211/ht.c
index b854483cf23f..e2d121bf2745 100644
--- a/net/mac80211/ht.c
+++ b/net/mac80211/ht.c
@@ -20,37 +20,33 @@
 #include "sta_info.h"
 #include "wme.h"
 
-int ieee80211_ht_cap_ie_to_ht_info(struct ieee80211_ht_cap *ht_cap_ie,
-                                   struct ieee80211_ht_info *ht_info)
+void ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_ht_cap *ht_cap_ie,
+                                       struct ieee80211_sta_ht_cap *ht_cap)
 {
 
-        if (ht_info == NULL)
-                return -EINVAL;
+        BUG_ON(!ht_cap);
 
-        memset(ht_info, 0, sizeof(*ht_info));
+        memset(ht_cap, 0, sizeof(*ht_cap));
 
         if (ht_cap_ie) {
                 u8 ampdu_info = ht_cap_ie->ampdu_params_info;
 
-                ht_info->ht_supported = 1;
-                ht_info->cap = le16_to_cpu(ht_cap_ie->cap_info);
-                ht_info->ampdu_factor =
-                        ampdu_info & IEEE80211_HT_CAP_AMPDU_FACTOR;
-                ht_info->ampdu_density =
-                        (ampdu_info & IEEE80211_HT_CAP_AMPDU_DENSITY) >> 2;
-                memcpy(ht_info->supp_mcs_set, ht_cap_ie->supp_mcs_set, 16);
+                ht_cap->ht_supported = true;
+                ht_cap->cap = le16_to_cpu(ht_cap_ie->cap_info);
+                ht_cap->ampdu_factor =
+                        ampdu_info & IEEE80211_HT_AMPDU_PARM_FACTOR;
+                ht_cap->ampdu_density =
+                        (ampdu_info & IEEE80211_HT_AMPDU_PARM_DENSITY) >> 2;
+                memcpy(&ht_cap->mcs, &ht_cap_ie->mcs, sizeof(ht_cap->mcs));
         } else
-                ht_info->ht_supported = 0;
-
-        return 0;
+                ht_cap->ht_supported = false;
 }
 
-int ieee80211_ht_addt_info_ie_to_ht_bss_info(
-                        struct ieee80211_ht_addt_info *ht_add_info_ie,
+void ieee80211_ht_info_ie_to_ht_bss_info(
+                        struct ieee80211_ht_info *ht_add_info_ie,
                         struct ieee80211_ht_bss_info *bss_info)
 {
-        if (bss_info == NULL)
-                return -EINVAL;
+        BUG_ON(!bss_info);
 
         memset(bss_info, 0, sizeof(*bss_info));
 
@@ -62,8 +58,119 @@ int ieee80211_ht_addt_info_ie_to_ht_bss_info(
                 bss_info->bss_cap = ht_add_info_ie->ht_param;
                 bss_info->bss_op_mode = (u8)(op_mode & 0xff);
         }
+}
+
+/*
+ * ieee80211_handle_ht should be called only after the operating band
+ * has been determined as ht configuration depends on the hw's
+ * HT abilities for a specific band.
+ */
+u32 ieee80211_handle_ht(struct ieee80211_local *local,
+                        struct ieee80211_sta_ht_cap *req_ht_cap,
+                        struct ieee80211_ht_bss_info *req_bss_cap)
+{
+        struct ieee80211_conf *conf = &local->hw.conf;
+        struct ieee80211_supported_band *sband;
+        struct ieee80211_sta_ht_cap ht_cap;
+        struct ieee80211_ht_bss_info ht_bss_conf;
+        u32 changed = 0;
+        int i;
+        u8 max_tx_streams;
+        u8 tx_mcs_set_cap;
+        bool enable_ht = true;
+
+        sband = local->hw.wiphy->bands[conf->channel->band];
+
+        memset(&ht_cap, 0, sizeof(ht_cap));
+        memset(&ht_bss_conf, 0, sizeof(struct ieee80211_ht_bss_info));
+
+        /* HT is not supported */
+        if (!sband->ht_cap.ht_supported)
+                enable_ht = false;
+
+        /* disable HT */
+        if (!enable_ht) {
+                if (conf->flags & IEEE80211_CONF_SUPPORT_HT_MODE)
+                        changed |= BSS_CHANGED_HT;
+                conf->flags &= ~IEEE80211_CONF_SUPPORT_HT_MODE;
+                conf->ht_cap.ht_supported = false;
+                return changed;
+        }
+
+
+        if (!(conf->flags & IEEE80211_CONF_SUPPORT_HT_MODE))
+                changed |= BSS_CHANGED_HT;
+
+        conf->flags |= IEEE80211_CONF_SUPPORT_HT_MODE;
+        ht_cap.ht_supported = true;
+
+        ht_cap.cap = req_ht_cap->cap & sband->ht_cap.cap;
+        ht_cap.cap &= ~IEEE80211_HT_CAP_SM_PS;
+        ht_cap.cap |= sband->ht_cap.cap & IEEE80211_HT_CAP_SM_PS;
+
+        ht_bss_conf.primary_channel = req_bss_cap->primary_channel;
+        ht_bss_conf.bss_cap = req_bss_cap->bss_cap;
+        ht_bss_conf.bss_op_mode = req_bss_cap->bss_op_mode;
+
+        ht_cap.ampdu_factor = req_ht_cap->ampdu_factor;
+        ht_cap.ampdu_density = req_ht_cap->ampdu_density;
+
+        /* own MCS TX capabilities */
+        tx_mcs_set_cap = sband->ht_cap.mcs.tx_params;
+
+        /*
+         * configure supported Tx MCS according to requested MCS
+         * (based in most cases on Rx capabilities of peer) and self
+         * Tx MCS capabilities (as defined by low level driver HW
+         * Tx capabilities)
+         */
+
+        /* can we TX with MCS rates? */
+        if (!(tx_mcs_set_cap & IEEE80211_HT_MCS_TX_DEFINED))
+                goto check_changed;
+
+        /* Counting from 0, therefore +1 */
+        if (tx_mcs_set_cap & IEEE80211_HT_MCS_TX_RX_DIFF)
+                max_tx_streams =
+                        ((tx_mcs_set_cap & IEEE80211_HT_MCS_TX_MAX_STREAMS_MASK)
+                                >> IEEE80211_HT_MCS_TX_MAX_STREAMS_SHIFT) + 1;
+        else
+                max_tx_streams = IEEE80211_HT_MCS_TX_MAX_STREAMS;
+
+        /*
+         * 802.11n D5.0 20.3.5 / 20.6 says:
+         * - indices 0 to 7 and 32 are single spatial stream
+         * - 8 to 31 are multiple spatial streams using equal modulation
+         *   [8..15 for two streams, 16..23 for three and 24..31 for four]
+         * - remainder are multiple spatial streams using unequal modulation
+         */
+        for (i = 0; i < max_tx_streams; i++)
+                ht_cap.mcs.rx_mask[i] =
+                        sband->ht_cap.mcs.rx_mask[i] &
+                                        req_ht_cap->mcs.rx_mask[i];
+
+        if (tx_mcs_set_cap & IEEE80211_HT_MCS_TX_UNEQUAL_MODULATION)
+                for (i = IEEE80211_HT_MCS_UNEQUAL_MODULATION_START_BYTE;
+                     i < IEEE80211_HT_MCS_MASK_LEN; i++)
+                        ht_cap.mcs.rx_mask[i] =
+                                sband->ht_cap.mcs.rx_mask[i] &
+                                        req_ht_cap->mcs.rx_mask[i];
+
+        /* handle MCS rate 32 too */
+        if (sband->ht_cap.mcs.rx_mask[32/8] &
+            req_ht_cap->mcs.rx_mask[32/8] & 1)
+                ht_cap.mcs.rx_mask[32/8] |= 1;
+
+ check_changed:
+        /* if bss configuration changed store the new one */
+        if (memcmp(&conf->ht_cap, &ht_cap, sizeof(ht_cap)) ||
+            memcmp(&conf->ht_bss_conf, &ht_bss_conf, sizeof(ht_bss_conf))) {
+                changed |= BSS_CHANGED_HT;
+                memcpy(&conf->ht_cap, &ht_cap, sizeof(ht_cap));
+                memcpy(&conf->ht_bss_conf, &ht_bss_conf, sizeof(ht_bss_conf));
+        }
 
-        return 0;
+        return changed;
 }
 
 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
@@ -794,7 +901,7 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
          * check if configuration can support the BA policy
          * and if buffer size does not exceeds max value */
         if (((ba_policy != 1)
-                && (!(conf->ht_conf.cap & IEEE80211_HT_CAP_DELAY_BA)))
+                && (!(conf->ht_cap.cap & IEEE80211_HT_CAP_DELAY_BA)))
                 || (buf_size > IEEE80211_MAX_AMPDU_BUF)) {
                 status = WLAN_STATUS_INVALID_QOS_PARAM;
 #ifdef CONFIG_MAC80211_HT_DEBUG
@@ -812,7 +919,7 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 
                 sband = local->hw.wiphy->bands[conf->channel->band];
                 buf_size = IEEE80211_MIN_AMPDU_BUF;
-                buf_size = buf_size << sband->ht_info.ampdu_factor;
+                buf_size = buf_size << sband->ht_cap.ampdu_factor;
         }