mac80211: support VHT capability overrides

Support the cfg80211 API to override VHT capabilities
on association.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 98 insertions, 0 deletions

diff --git a/net/mac80211/vht.c b/net/mac80211/vht.c
index a2c2258bc84e..cacc1c74556a 100644
--- a/net/mac80211/vht.c
+++ b/net/mac80211/vht.c
@@ -13,6 +13,104 @@
 #include "rate.h"
 
 
+static void __check_vhtcap_disable(struct ieee80211_sub_if_data *sdata,
+                                   struct ieee80211_sta_vht_cap *vht_cap,
+                                   u32 flag)
+{
+        __le32 le_flag = cpu_to_le32(flag);
+
+        if (sdata->u.mgd.vht_capa_mask.vht_cap_info & le_flag &&
+            !(sdata->u.mgd.vht_capa.vht_cap_info & le_flag))
+                vht_cap->cap &= ~flag;
+}
+
+void ieee80211_apply_vhtcap_overrides(struct ieee80211_sub_if_data *sdata,
+                                      struct ieee80211_sta_vht_cap *vht_cap)
+{
+        int i;
+        u16 rxmcs_mask, rxmcs_cap, rxmcs_n, txmcs_mask, txmcs_cap, txmcs_n;
+
+        if (!vht_cap->vht_supported)
+                return;
+
+        if (sdata->vif.type != NL80211_IFTYPE_STATION)
+                return;
+
+        __check_vhtcap_disable(sdata, vht_cap,
+                               IEEE80211_VHT_CAP_RXLDPC);
+        __check_vhtcap_disable(sdata, vht_cap,
+                               IEEE80211_VHT_CAP_SHORT_GI_80);
+        __check_vhtcap_disable(sdata, vht_cap,
+                               IEEE80211_VHT_CAP_SHORT_GI_160);
+        __check_vhtcap_disable(sdata, vht_cap,
+                               IEEE80211_VHT_CAP_TXSTBC);
+        __check_vhtcap_disable(sdata, vht_cap,
+                               IEEE80211_VHT_CAP_SU_BEAMFORMER_CAPABLE);
+        __check_vhtcap_disable(sdata, vht_cap,
+                               IEEE80211_VHT_CAP_SU_BEAMFORMEE_CAPABLE);
+        __check_vhtcap_disable(sdata, vht_cap,
+                               IEEE80211_VHT_CAP_RX_ANTENNA_PATTERN);
+        __check_vhtcap_disable(sdata, vht_cap,
+                               IEEE80211_VHT_CAP_TX_ANTENNA_PATTERN);
+
+        /* Allow user to decrease AMPDU length exponent */
+        if (sdata->u.mgd.vht_capa_mask.vht_cap_info &
+            cpu_to_le32(IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK)) {
+                u32 cap, n;
+
+                n = le32_to_cpu(sdata->u.mgd.vht_capa.vht_cap_info) &
+                        IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK;
+                n >>= IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_SHIFT;
+                cap = vht_cap->cap & IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK;
+                cap >>= IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_SHIFT;
+
+                if (n < cap) {
+                        vht_cap->cap &=
+                                ~IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK;
+                        vht_cap->cap |=
+                                n << IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_SHIFT;
+                }
+        }
+
+        /* Allow the user to decrease MCSes */
+        rxmcs_mask =
+                le16_to_cpu(sdata->u.mgd.vht_capa_mask.supp_mcs.rx_mcs_map);
+        rxmcs_n = le16_to_cpu(sdata->u.mgd.vht_capa.supp_mcs.rx_mcs_map);
+        rxmcs_n &= rxmcs_mask;
+        rxmcs_cap = le16_to_cpu(vht_cap->vht_mcs.rx_mcs_map);
+
+        txmcs_mask =
+                le16_to_cpu(sdata->u.mgd.vht_capa_mask.supp_mcs.tx_mcs_map);
+        txmcs_n = le16_to_cpu(sdata->u.mgd.vht_capa.supp_mcs.tx_mcs_map);
+        txmcs_n &= txmcs_mask;
+        txmcs_cap = le16_to_cpu(vht_cap->vht_mcs.tx_mcs_map);
+        for (i = 0; i < 8; i++) {
+                u8 m, n, c;
+
+                m = (rxmcs_mask >> 2*i) & IEEE80211_VHT_MCS_NOT_SUPPORTED;
+                n = (rxmcs_n >> 2*i) & IEEE80211_VHT_MCS_NOT_SUPPORTED;
+                c = (rxmcs_cap >> 2*i) & IEEE80211_VHT_MCS_NOT_SUPPORTED;
+
+                if (m && ((c != IEEE80211_VHT_MCS_NOT_SUPPORTED && n < c) ||
+                          n == IEEE80211_VHT_MCS_NOT_SUPPORTED)) {
+                        rxmcs_cap &= ~(3 << 2*i);
+                        rxmcs_cap |= (rxmcs_n & (3 << 2*i));
+                }
+
+                m = (txmcs_mask >> 2*i) & IEEE80211_VHT_MCS_NOT_SUPPORTED;
+                n = (txmcs_n >> 2*i) & IEEE80211_VHT_MCS_NOT_SUPPORTED;
+                c = (txmcs_cap >> 2*i) & IEEE80211_VHT_MCS_NOT_SUPPORTED;
+
+                if (m && ((c != IEEE80211_VHT_MCS_NOT_SUPPORTED && n < c) ||
+                          n == IEEE80211_VHT_MCS_NOT_SUPPORTED)) {
+                        txmcs_cap &= ~(3 << 2*i);
+                        txmcs_cap |= (txmcs_n & (3 << 2*i));
+                }
+        }
+        vht_cap->vht_mcs.rx_mcs_map = cpu_to_le16(rxmcs_cap);
+        vht_cap->vht_mcs.tx_mcs_map = cpu_to_le16(txmcs_cap);
+}
+
 void
 ieee80211_vht_cap_ie_to_sta_vht_cap(struct ieee80211_sub_if_data *sdata,
                                     struct ieee80211_supported_band *sband,