nl80211: add support for mcs masks

Allow to set mcs masks through nl80211. We also allow to set MCS
rates but no legacy rates (and vice versa).

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 4f98fae13307072d036f23b16a51698ef5d16641..ad56e21a9f10c0dfbb9b272b183a33dd90e0c1ca 100644 (file)
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -1475,6 +1475,7 @@ enum nl80211_attrs {
 #define NL80211_ATTR_FEATURE_FLAGS NL80211_ATTR_FEATURE_FLAGS
 
 #define NL80211_MAX_SUPP_RATES                 32
+#define NL80211_MAX_SUPP_HT_RATES              77
 #define NL80211_MAX_SUPP_REG_RULES             32
 #define NL80211_TKIP_DATA_OFFSET_ENCR_KEY      0
 #define NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY    16
@@ -2405,12 +2406,15 @@ enum nl80211_key_attributes {
  *     in an array of rates as defined in IEEE 802.11 7.3.2.2 (u8 values with
  *     1 = 500 kbps) but without the IE length restriction (at most
  *     %NL80211_MAX_SUPP_RATES in a single array).
+ * @NL80211_TXRATE_MCS: HT (MCS) rates allowed for TX rate selection
+ *     in an array of MCS numbers.
  * @__NL80211_TXRATE_AFTER_LAST: internal
  * @NL80211_TXRATE_MAX: highest TX rate attribute
  */
 enum nl80211_tx_rate_attributes {
        __NL80211_TXRATE_INVALID,
        NL80211_TXRATE_LEGACY,
+       NL80211_TXRATE_MCS,
 
        /* keep last */
        __NL80211_TXRATE_AFTER_LAST,

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 5bb3ed4f99f5d426d2b2d219768ccd0fda417be7..2964205332f42ba1f7677443a2ddd90a7d59a9d1 100644 (file)
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1232,8 +1232,7 @@ enum wiphy_params_flags {
 struct cfg80211_bitrate_mask {
        struct {
                u32 legacy;
-               /* TODO: add support for masking MCS rates; e.g.: */
-               /* u8 mcs[IEEE80211_HT_MCS_MASK_LEN]; */
+               u8 mcs[IEEE80211_HT_MCS_MASK_LEN];
        } control[IEEE80211_NUM_BANDS];
 };
 /**

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index c42173f947efa149c40eae716cd32c3b25981ca2..c910b0750dc208e960225f8a9d42d927b94b6ba4 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5393,9 +5393,39 @@ static u32 rateset_to_mask(struct ieee80211_supported_band *sband,
        return mask;
 }
 
+static bool ht_rateset_to_mask(struct ieee80211_supported_band *sband,
+                              u8 *rates, u8 rates_len,
+                              u8 mcs[IEEE80211_HT_MCS_MASK_LEN])
+{
+       u8 i;
+
+       memset(mcs, 0, IEEE80211_HT_MCS_MASK_LEN);
+
+       for (i = 0; i < rates_len; i++) {
+               int ridx, rbit;
+
+               ridx = rates[i] / 8;
+               rbit = BIT(rates[i] % 8);
+
+               /* check validity */
+               if ((ridx < 0) || (ridx > IEEE80211_HT_MCS_MASK_LEN))
+                       return false;
+
+               /* check availability */
+               if (sband->ht_cap.mcs.rx_mask[ridx] & rbit)
+                       mcs[ridx] |= rbit;
+               else
+                       return false;
+       }
+
+       return true;
+}
+
 static const struct nla_policy nl80211_txattr_policy[NL80211_TXRATE_MAX + 1] = {
        [NL80211_TXRATE_LEGACY] = { .type = NLA_BINARY,
                                    .len = NL80211_MAX_SUPP_RATES },
+       [NL80211_TXRATE_MCS] = { .type = NLA_BINARY,
+                                .len = NL80211_MAX_SUPP_HT_RATES },
 };
 
 static int nl80211_set_tx_bitrate_mask(struct sk_buff *skb,
@@ -5421,12 +5451,20 @@ static int nl80211_set_tx_bitrate_mask(struct sk_buff *skb,
                sband = rdev->wiphy.bands[i];
                mask.control[i].legacy =
                        sband ? (1 << sband->n_bitrates) - 1 : 0;
+               if (sband)
+                       memcpy(mask.control[i].mcs,
+                              sband->ht_cap.mcs.rx_mask,
+                              sizeof(mask.control[i].mcs));
+               else
+                       memset(mask.control[i].mcs, 0,
+                              sizeof(mask.control[i].mcs));
        }
 
        /*
         * The nested attribute uses enum nl80211_band as the index. This maps
         * directly to the enum ieee80211_band values used in cfg80211.
         */
+       BUILD_BUG_ON(NL80211_MAX_SUPP_HT_RATES > IEEE80211_HT_MCS_MASK_LEN * 8);
        nla_for_each_nested(tx_rates, info->attrs[NL80211_ATTR_TX_RATES], rem)
        {
                enum ieee80211_band band = nla_type(tx_rates);
@@ -5442,7 +5480,28 @@ static int nl80211_set_tx_bitrate_mask(struct sk_buff *skb,
                                sband,
                                nla_data(tb[NL80211_TXRATE_LEGACY]),
                                nla_len(tb[NL80211_TXRATE_LEGACY]));
-                       if (mask.control[band].legacy == 0)
+               }
+               if (tb[NL80211_TXRATE_MCS]) {
+                       if (!ht_rateset_to_mask(
+                                       sband,
+                                       nla_data(tb[NL80211_TXRATE_MCS]),
+                                       nla_len(tb[NL80211_TXRATE_MCS]),
+                                       mask.control[band].mcs))
+                               return -EINVAL;
+               }
+
+               if (mask.control[band].legacy == 0) {
+                       /* don't allow empty legacy rates if HT
+                        * is not even supported. */
+                       if (!rdev->wiphy.bands[band]->ht_cap.ht_supported)
+                               return -EINVAL;
+
+                       for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++)
+                               if (mask.control[band].mcs[i])
+                                       break;
+
+                       /* legacy and mcs rates may not be both empty */
+                       if (i == IEEE80211_HT_MCS_MASK_LEN)
                                return -EINVAL;
                }
        }