diagnostic: get the ratio of close dht nodes with announce/store support

toxcore/DHT.c

@@ -3060,6 +3060,32 @@ bool dht_non_lan_connected(const DHT *dht)
     return false;
 }
 
+float dht_get_announce_capability_ratio(const DHT *dht) {
+	float num_valid_close_clients = 0.f;
+	float num_valid_close_clients_with_cap = 0.f;
+	for (size_t i = 0; i < LCLIENT_LIST; i++) {
+		const Client_data *const client = dht_get_close_client(dht, i);
+
+		// check if client is valid
+		if (assoc_timeout(dht->cur_time, &client->assoc4) &&
+                assoc_timeout(dht->cur_time, &client->assoc6)) {
+			continue;
+        }
+
+		num_valid_close_clients += 1.f;
+
+		if (client->announce_node) {
+			num_valid_close_clients_with_cap += 1.f;
+		}
+	}
+
+	if (num_valid_close_clients == 0.f) {
+		return 0.f;
+	}
+
+	return num_valid_close_clients_with_cap / num_valid_close_clients;
+}
+
 /** @brief Copies our own ip_port structure to `dest`.
  *
  * WAN addresses take priority over LAN addresses.

toxcore/DHT.h

@@ -514,6 +514,14 @@ bool dht_isconnected(const DHT *dht);
 non_null()
 bool dht_non_lan_connected(const DHT *dht);
 
+/**
+ * This function returns the ratio of close dht nodes that are known to support announce/store.
+ *
+ * @return ratio
+ */
+non_null()
+float dht_get_announce_capability_ratio(const DHT *dht);
+
 /** @brief Attempt to add client with ip_port and public_key to the friends client list
  * and close_clientlist.
  *

toxcore/tox_private.c

@@ -147,3 +147,12 @@ bool tox_dht_get_nodes(const Tox *tox, const uint8_t *public_key, const char *ip
 
     return true;
 }
+
+float tox_dht_get_announce_capability_ratio(const Tox *tox) {
+    tox_lock(tox);
+    float ret =  dht_get_announce_capability_ratio(tox->m->dht);
+    tox_unlock(tox);
+
+    return ret;
+}
+

toxcore/tox_private.h

@@ -139,6 +139,13 @@ typedef enum Tox_Err_Dht_Get_Nodes {
 bool tox_dht_get_nodes(const Tox *tox, const uint8_t *public_key, const char *ip, uint16_t port,
                        const uint8_t *target_public_key, Tox_Err_Dht_Get_Nodes *error);
 
+/**
+ * This function returns the ratio of close dht nodes that are known to support announce/store.
+ *
+ * @return ratio
+ */
+float tox_dht_get_announce_capability_ratio(const Tox *tox);
+
 #ifdef __cplusplus
 }
 #endif