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>

1 files changed, 60 insertions, 1 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index c42173f947ef..c910b0750dc2 100644
--- 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;
                 }
         }