hostapd: Fix vht_capab 'Maximum A-MPDU Length Exponent' handling

As per IEEE Std 802.11ac-2013, 'Maximum A-MPDU Length Exponent' field
value is in the range of 0 to 7. Previous implementation assumed EXP0 to
be the maximum length (bits 23, 24 and 25 set) what is incorrect.

This patch adds options to set it up within the 0 to 7 range.

Signed-off-by: Bartosz Markowski <bartosz.markowski@tieto.com>

hostapd/config_file.c

@@ -1096,8 +1096,20 @@ static int hostapd_config_vht_capab(struct hostapd_config *conf,
 		conf->vht_capab |= VHT_CAP_VHT_TXOP_PS;
 	if (os_strstr(capab, "[HTC-VHT]"))
 		conf->vht_capab |= VHT_CAP_HTC_VHT;
-	if (os_strstr(capab, "[MAX-A-MPDU-LEN-EXP0]"))
-		conf->vht_capab |= VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT;
+	if (os_strstr(capab, "[MAX-A-MPDU-LEN-EXP7]"))
+		conf->vht_capab |= VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MAX;
+	else if (os_strstr(capab, "[MAX-A-MPDU-LEN-EXP6]"))
+		conf->vht_capab |= VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_6;
+	else if (os_strstr(capab, "[MAX-A-MPDU-LEN-EXP5]"))
+		conf->vht_capab |= VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_5;
+	else if (os_strstr(capab, "[MAX-A-MPDU-LEN-EXP4]"))
+		conf->vht_capab |= VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_4;
+	else if (os_strstr(capab, "[MAX-A-MPDU-LEN-EXP3]"))
+		conf->vht_capab |= VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_3;
+	else if (os_strstr(capab, "[MAX-A-MPDU-LEN-EXP2]"))
+		conf->vht_capab |= VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_2;
+	else if (os_strstr(capab, "[MAX-A-MPDU-LEN-EXP1]"))
+		conf->vht_capab |= VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_1;
 	if (os_strstr(capab, "[VHT-LINK-ADAPT2]") &&
 	    (conf->vht_capab & VHT_CAP_HTC_VHT))
 		conf->vht_capab |= VHT_CAP_VHT_LINK_ADAPTATION_VHT_UNSOL_MFB;

src/ap/hw_features.c

@@ -764,7 +764,7 @@ static int ieee80211ac_supported_vht_capab(struct hostapd_iface *iface)
 	VHT_CAP_CHECK(VHT_CAP_MU_BEAMFORMEE_CAPABLE);
 	VHT_CAP_CHECK(VHT_CAP_VHT_TXOP_PS);
 	VHT_CAP_CHECK(VHT_CAP_HTC_VHT);
-	VHT_CAP_CHECK_MAX(VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT);
+	VHT_CAP_CHECK_MAX(VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MAX);
 	VHT_CAP_CHECK(VHT_CAP_VHT_LINK_ADAPTATION_VHT_UNSOL_MFB);
 	VHT_CAP_CHECK(VHT_CAP_VHT_LINK_ADAPTATION_VHT_MRQ_MFB);
 	VHT_CAP_CHECK(VHT_CAP_RX_ANTENNA_PATTERN);

src/common/ieee802_11_defs.h

@@ -758,7 +758,14 @@ struct ieee80211_vht_operation {
 #define VHT_CAP_MU_BEAMFORMEE_CAPABLE               ((u32) BIT(20))
 #define VHT_CAP_VHT_TXOP_PS                         ((u32) BIT(21))
 #define VHT_CAP_HTC_VHT                             ((u32) BIT(22))
-#define VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT          ((u32) BIT(23) | \
+
+#define VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_1        ((u32) BIT(23))
+#define VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_2        ((u32) BIT(24))
+#define VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_3        ((u32) BIT(23) | BIT(24))
+#define VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_4        ((u32) BIT(25))
+#define VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_5        ((u32) BIT(23) | BIT(25))
+#define VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_6        ((u32) BIT(24) | BIT(25))
+#define VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MAX      ((u32) BIT(23) | \
 							   BIT(24) | BIT(25))
 #define VHT_CAP_VHT_LINK_ADAPTATION_VHT_UNSOL_MFB   ((u32) BIT(27))
 #define VHT_CAP_VHT_LINK_ADAPTATION_VHT_MRQ_MFB     ((u32) BIT(26) | BIT(27))