nimble/host: implement robust gatt caching (server side)

nimble/host/include/host/ble_att.h

@@ -110,6 +110,9 @@ struct os_mbuf;
 /**Insufficient Resources to complete the request. */
 #define BLE_ATT_ERR_INSUFFICIENT_RES        0x11
 
+/** The server requests the client to rediscover the database. */
+#define BLE_ATT_ERR_DB_OUT_OF_SYNC          0x12
+
 /**Requested value is not allowed. */
 #define BLE_ATT_ERR_VALUE_NOT_ALLOWED       0x13
 

nimble/host/include/host/ble_gatt.h

@@ -201,6 +201,9 @@ struct ble_hs_cfg;
 
 /** @} */
 
+/** Client supported features size. For now only 3 bits in first octet are defined */
+#define BLE_GATT_CHR_CLI_SUP_FEAT_SZ 1
+
 /*** @client. */
 /** Represents a GATT error. */
 struct ble_gatt_error {
@@ -1253,6 +1256,16 @@ int ble_gatts_peer_cl_sup_feat_get(uint16_t conn_handle, uint8_t *out_supported_
 int ble_gatts_read_cccd(uint16_t conn_handle, uint16_t chr_val_handle,
                         uint8_t *cccd_value);
 
+/**
+ * Calculates Database Hash characteristic value based on service definitions
+ * in the GATT database.
+ *
+ * @return                      0 on success;
+ *                              BLE_HS_EUNKNOWN if initializing CMAC session
+ *                                  or computing CMAC tag value fails.
+ *
+ */
+int ble_gatts_calculate_db_hash(void);
 #ifdef __cplusplus
 }
 #endif

nimble/host/include/host/ble_store.h

@@ -29,6 +29,7 @@
 
 #include <inttypes.h>
 #include "nimble/ble.h"
+#include "host/ble_gatt.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -40,14 +41,19 @@ extern "C" {
  * @{
  */
 /** Object type: Our security material. */
-#define BLE_STORE_OBJ_TYPE_OUR_SEC      1
+#define BLE_STORE_OBJ_TYPE_OUR_SEC                 1
 
 /** Object type: Peer security material. */
-#define BLE_STORE_OBJ_TYPE_PEER_SEC     2
+#define BLE_STORE_OBJ_TYPE_PEER_SEC                2
 
 /** Object type: Client Characteristic Configuration Descriptor. */
-#define BLE_STORE_OBJ_TYPE_CCCD         3
+#define BLE_STORE_OBJ_TYPE_CCCD                    3
 
+/** Object type: Peer last known database hash. */
+#define BLE_STORE_OBJ_TYPE_DB_HASH                 4
+
+/** Object type: Peer Client Supported Features. */
+#define BLE_STORE_OBJ_TYPE_PEER_CL_SUP_FEAT        5
 /** @} */
 
 /**
@@ -154,6 +160,61 @@ struct ble_store_value_cccd {
     unsigned value_changed:1;
 };
 
+/**
+ * Used as key for lookups of stored database hash.
+ * This struct corresponds to the BLE_STORE_OBJ_TYPE_DB_HASH store object
+ * type.
+ */
+struct ble_store_key_db_hash {
+    /**
+     * Key by peer identity address;
+     * peer_addr=BLE_ADDR_NONE means don't key off peer.
+     */
+    ble_addr_t peer_addr;
+
+    /** Number of results to skip; 0 means retrieve the first match. */
+    uint8_t idx;
+};
+
+/**
+ * Represents a stored database hash of a peer. This struct
+ * corresponds to the BLE_STORE_OBJ_TYPE_DB_HASH store object type.
+ */
+struct ble_store_value_db_hash {
+    /** The peer address associated with the stored database hash. */
+    ble_addr_t peer_addr;
+    /** Database hash; can be used to determine whether the peer
+     * is change aware/unaware. */
+    const uint8_t *db_hash;
+ };
+
+ /**
+ * Used as a key for lookups of stored client supported features of specific
+ * peer. This struct corresponds to the BLE_STORE_OBJ_TYPE_PEER_CL_SUP_FEAT
+ * store object type.
+ */
+struct ble_store_key_cl_sup_feat {
+    /**
+     * Key by peer identity address;
+     * peer_addr=BLE_ADDR_NONE means don't key off peer.
+     */
+    ble_addr_t peer_addr;
+
+    /** Number of results to skip; 0 means retrieve the first match. */
+    uint8_t idx;
+};
+
+/**
+ * Represents a stored client supported features of specific peer. This struct
+ * corresponds to the BLE_STORE_OBJ_TYPE_PEER_CL_SUP_FEAT store object type.
+ */
+ struct ble_store_value_cl_sup_feat {
+     /** The peer address associated with the stored supported features. */
+     ble_addr_t peer_addr;
+     /** Client supported features of a specific peer. */
+     uint8_t peer_cl_sup_feat[BLE_GATT_CHR_CLI_SUP_FEAT_SZ];
+ };
+
 /**
  * Used as a key for store lookups.  This union must be accompanied by an
  * object type code to indicate which field is valid.
@@ -163,6 +224,10 @@ union ble_store_key {
     struct ble_store_key_sec sec;
     /** Key for Client Characteristic Configuration Descriptor store lookups. */
     struct ble_store_key_cccd cccd;
+    /** Key for database hash store lookups */
+    struct ble_store_key_db_hash db_hash;
+    /** Key for Peer Client Supported Features store lookpus. */
+    struct ble_store_key_cl_sup_feat feat;
 };
 
 /**
@@ -174,6 +239,10 @@ union ble_store_value {
     struct ble_store_value_sec sec;
     /** Stored Client Characteristic Configuration Descriptor. */
     struct ble_store_value_cccd cccd;
+    /** Stored database hash. */
+    struct ble_store_value_db_hash db_hash;
+    /** Stored Client Supported Features. */
+    struct ble_store_value_cl_sup_feat feat;
 };
 
 /** Represents an event associated with the BLE Store. */
@@ -556,6 +625,132 @@ int ble_store_write_cccd(const struct ble_store_value_cccd *value);
  */
 int ble_store_delete_cccd(const struct ble_store_key_cccd *key);
 
+/**
+ * @brief Writes a database hash to a storage.
+ *
+ * This function writes database hash value to a storage based on the
+ * provided value.
+ *
+ * @param value                 A pointer to a `ble_store_value_db_hash`
+ *                                  structure representing the database hash
+ *                                  to be written to a storage.
+ *
+ * @return                      0 if the database hash was successfully
+ *                                  written to a storage;
+ *                              Non-zero on error.
+ */
+int ble_store_write_db_hash(const struct ble_store_value_db_hash *value);
+
+/**
+ * @brief Reads a database hash from a storage.
+ *
+ * This function reads a database hash from a storage based on the provided key
+ * and stores the retrieved value in the specified output structure.
+ *
+ * @param key                   A pointer to a `ble_store_key_db_hash`
+ *                                  structure representing the key to identify
+ *                                  the database hash to be read.
+ * @param out_value             A pointer to a `ble_store_value_db_hash`
+ *                                  structure to store the database hash value
+ *                                  read from a storage.
+ *
+ * @return                      0 if the database hash was successfully read
+ *                                  and stored in the `out_value` structure;
+ *                              Non-zero on error.
+ */
+int ble_store_read_db_hash(const struct ble_store_key_db_hash *key,
+                           struct ble_store_value_db_hash *out_value);
+
+/**
+ * @brief Deletes a database hash from a storage.
+ *
+ * This function deletes a database hash from a storage based on the provided
+ * key.
+ *
+ * @param key                   A pointer to a `ble_store_key_db_hash`
+ *                                  structure identifying the database hash to
+ *                                  be deleted from a storage.
+ *
+ * @return                      0 if the database hash was successfully deleted
+ *                                  from a storage;
+ *                              Non-zero on error.
+ */
+int ble_store_delete_db_hash(const struct ble_store_value_db_hash *key);
+
+/**
+ * @brief Generates a storage key for a database hash entry from its value.
+ *
+ * This function generates a storage key for a database hash entry based on
+ * the provided database hash value.
+ *
+ * @param out_key               A pointer to a `ble_store_key_db_hash`
+ *                                  structure where the generated key will be
+ *                                  stored.
+ * @param value                 A pointer to a `ble_store_value_db_hash`
+ *                                  structure containing the security material
+ *                                  value from which the key will be generated.
+ */
+void ble_store_key_from_value_db_hash(struct ble_store_key_db_hash *out_key,
+                                      const struct ble_store_value_db_hash *value);
+
+/**
+ * @brief Reads Client Supported Features value from a storage
+ *
+ * This function reads client supported features value from a storage based
+ * on the provied key and stores the retrieved value in the specified output
+ * structure.
+ *
+ * @param key                   A pointer to a 'ble_store_key_cl_sup_feat'
+ *                                  struct representing the key to identify
+ *                                  Client Supported Features value to be read.
+ * @param out_value             A pointer to a 'ble_store_value_cl_sup_feat'
+ *                                  struct to store the Client Supported
+ *                                  Features value read from a storage
+ *
+ * @return                      0 if the Client Supported Features values was
+ *                                  successfully read and stored in the
+ *                                  'out_value' structure;
+ *                              Non-zero on error
+ */
+int
+ble_store_read_peer_cl_sup_feat(const struct ble_store_key_cl_sup_feat *key,
+                                struct ble_store_value_cl_sup_feat *out_value);
+
+/**
+ * @brief Writes a Client Supported Features value to a storage.
+ *
+ * This function writes a Client Supported Features value to a storage based on
+ * the provided value
+ *
+ * @param value                 A pointer to a 'ble_store_value_cl_sup_feat'
+ *                                  structure representing the Client Supported
+ *                                  Features value to be written to a storage.
+ *
+ * @return                      0 if the value was successfully written to
+ *                                  a storage;
+ *                              Non-zero on error.
+ */
+int
+ble_store_write_peer_cl_sup_feat(const struct ble_store_value_cl_sup_feat
+                                 *value);
+
+/**
+ * @brief Deletes a Client Supported Features value from a storage.
+ *
+ * This function deletes a Client Supported Features value from a storage based
+ * on the provided key.
+ *
+ * @param key                   A pointer to a 'ble_store_key_cl_sup_feat'
+ *                                  structure identifying the Client Supported
+ *                                  Features value to be deleted from
+ *                                  a storage.
+ *
+ * @return                      0 if the Client Supported Features value was
+ *                                  successfully written to a storage;
+ *                              Non-zero on error.
+ */
+int ble_store_delete_peer_cl_sup_feat(const struct ble_store_key_cl_sup_feat
+                                          *key);
 
 /**
  * @brief Generates a storage key for a security material entry from its value.
@@ -587,6 +782,26 @@ void ble_store_key_from_value_sec(struct ble_store_key_sec *out_key,
 void ble_store_key_from_value_cccd(struct ble_store_key_cccd *out_key,
                                    const struct ble_store_value_cccd *value);
 
+/**
+ * @brief Generates a storage key for a Client Supported Features entry from
+ * its value
+ *
+ * This function generates a storage key for a Client Supported Features value
+ * entry based on the provided value.
+ *
+ * @param out_key               A pointer to a 'ble_store_key_cl_sup_feat'
+ *                                  structure where the generated key will be
+ *                                  stored.
+ * @param value                 A pointer to a 'ble_store_value_cl_sup_feat'
+ *                                  structure containing the Client Supported
+ *                                  Features value from which the key will be
+ *                                  generated.
+ */
+void
+ble_store_key_from_value_peer_cl_sup_feat(struct ble_store_key_cl_sup_feat
+                                          *out_key,
+                                          const struct ble_store_value_cl_sup_feat
+                                          *value);
 
 /**
  * @brief Generates a storage key from a value based on the object type.

nimble/host/services/gatt/include/services/gatt/ble_svc_gatt.h

@@ -31,6 +31,7 @@ struct ble_hs_cfg;
 #define BLE_SVC_GATT_CHR_SERVICE_CHANGED_UUID16         0x2a05
 #define BLE_SVC_GATT_CHR_SERVER_SUPPORTED_FEAT_UUID16   0x2b3a
 #define BLE_SVC_GATT_CHR_CLIENT_SUPPORTED_FEAT_UUID16   0x2b29
+#define BLE_SVC_GATT_CHR_DATABASE_HASH_UUID16           0x2b2a
 
 uint8_t ble_svc_gatt_get_local_cl_supported_feat(void);
 void ble_svc_gatt_changed(uint16_t start_handle, uint16_t end_handle);