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 a2c2258..cacc1c7 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,