Advertise Supported Operating Classes elements in Beacon/Probe Response

Advertise current operating class in Beacon and Probe Response frames.
This Supported Operating Classes element is required by the standard
when extended channel switch is supported. However, since this element
doesn't reflect correctly the sub-band spectrum breakdown and can't be
effectively used by clients, publish only the minimal required part
which is the current operating class.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>

src/ap/beacon.c

@@ -326,6 +326,34 @@ static u8 * hostapd_eid_ecsa(struct hostapd_data *hapd, u8 *eid)
 }
 
 
+static u8 * hostapd_eid_supported_op_classes(struct hostapd_data *hapd, u8 *eid)
+{
+	u8 op_class, channel;
+
+	if (!(hapd->iface->drv_flags & WPA_DRIVER_FLAGS_AP_CSA) ||
+	    !hapd->iface->freq)
+		return eid;
+
+	if (ieee80211_freq_to_channel_ext(hapd->iface->freq,
+					  hapd->iconf->secondary_channel,
+					  hapd->iconf->vht_oper_chwidth,
+					  &op_class, &channel) ==
+	    NUM_HOSTAPD_MODES)
+		return eid;
+
+	*eid++ = WLAN_EID_SUPPORTED_OPERATING_CLASSES;
+	*eid++ = 2;
+
+	/* Current Operating Class */
+	*eid++ = op_class;
+
+	/* TODO: Advertise all the supported operating classes */
+	*eid++ = 0;
+
+	return eid;
+}
+
+
 static u8 * hostapd_gen_probe_resp(struct hostapd_data *hapd,
 				   const struct ieee80211_mgmt *req,
 				   int is_p2p, size_t *resp_len)
@@ -416,6 +444,8 @@ static u8 * hostapd_gen_probe_resp(struct hostapd_data *hapd,
 		hapd->cs_c_off_ecsa_proberesp = csa_pos - (u8 *) resp - 1;
 	pos = csa_pos;
 
+	pos = hostapd_eid_supported_op_classes(hapd, pos);
+
 #ifdef CONFIG_IEEE80211N
 	/* Secondary Channel Offset element */
 	/* TODO: The standard doesn't specify a position for this element. */
@@ -997,6 +1027,8 @@ int ieee802_11_build_ap_params(struct hostapd_data *hapd,
 		hapd->cs_c_off_ecsa_beacon = csa_pos - tail - 1;
 	tailpos = csa_pos;
 
+	tailpos = hostapd_eid_supported_op_classes(hapd, tailpos);
+
 #ifdef CONFIG_IEEE80211N
 	/* Secondary Channel Offset element */
 	/* TODO: The standard doesn't specify a position for this element. */