GAS: Calculate response buffer length of ANQP elements

Calculate the required length needed for the extra ANQP elements added
to GAS response buffer instead of using fixed size and truncating the
response if there was not sufficient space.

Signed-off-by: Max Stepanov <Max.Stepanov@intel.com>

src/ap/gas_serv.c

@@ -786,6 +786,24 @@ static void anqp_add_icon_binary_file(struct hostapd_data *hapd,
 #endif /* CONFIG_HS20 */
 
 
+static size_t anqp_get_required_len(struct hostapd_data *hapd,
+				    const u16 *infoid,
+				    unsigned int num_infoid)
+{
+	size_t len = 0;
+	unsigned int i;
+
+	for (i = 0; i < num_infoid; i++) {
+		struct anqp_element *elem = get_anqp_elem(hapd, infoid[i]);
+
+		if (elem)
+			len += 2 + 2 + wpabuf_len(elem->payload);
+	}
+
+	return len;
+}
+
+
 static struct wpabuf *
 gas_serv_build_gas_resp_payload(struct hostapd_data *hapd,
 				unsigned int request,
@@ -803,7 +821,7 @@ gas_serv_build_gas_resp_payload(struct hostapd_data *hapd,
 		len += 1000;
 	if (request & ANQP_REQ_ICON_REQUEST)
 		len += 65536;
-	len += num_extra_req * 1000;
+	len += anqp_get_required_len(hapd, extra_req, num_extra_req);
 
 	buf = wpabuf_alloc(len);
 	if (buf == NULL)