Bluetooth: extending API for OOB pairing

This change extends the Bluetooth API to support pairing with the OOB
data that are used in the Authentication Stage of the pairing procedure.
The LE Secure Connections specific API for OOB pairing is also added.
The general OOB API should be able to accomodate the LE legacy pairing
later on.

Signed-off-by: Kamil Piszczek <Kamil.Piszczek@nordicsemi.no>

include/bluetooth/conn.h

@@ -413,6 +413,59 @@ void bt_conn_cb_register(struct bt_conn_cb *cb);
  */
 void bt_set_bondable(bool enable);
 
+/** Allow/disallow remote OOB data to be used for pairing.
+ *
+ *  Set/clear the OOB data flag for SMP Pairing Request/Response data.
+ *  The initial value of this flag depends on BT_OOB_DATA_PRESENT Kconfig
+ *  setting.
+ *
+ *  @param enable Value allowing/disallowing remote OOB data.
+ */
+void bt_set_oob_data_flag(bool enable);
+
+/**
+ * @brief Set OOB data during LE SC pairing procedure
+ *
+ * This function allows to set OOB data during the LE SC pairing procedure. The
+ * function should only be called in response to the oob_data_request() callback
+ * provided that LE SC method is used for pairing.
+ *
+ * The user should submit OOB data according to the information received in the
+ * callback. This may yield three different configurations: with only local OOB
+ * data present, with only remote OOB data present or with both local and
+ * remote OOB data present.
+ *
+ * @param conn Connection object
+ * @param oobd_local Local OOB data or NULL if not present
+ * @param oobd_remote Remote OOB data or NULL if not present
+ *
+ *  @return Zero on success or error code otherwise, positive in case
+ *  of protocol error or negative (POSIX) in case of stack internal error
+ */
+int bt_le_oob_set_sc_data(struct bt_conn *conn,
+			  const struct bt_le_oob_sc_data *oobd_local,
+			  const struct bt_le_oob_sc_data *oobd_remote);
+
+/**
+ * @brief Get OOB data used for LE SC pairing procedure
+ *
+ * This function allows to get OOB data during the LE SC pairing procedure that
+ * were set by the bt_le_oob_set_sc_data() API.
+ *
+ *  Note: The OOB data will only be available as long as the connection object
+ *  associated with it is valid.
+ *
+ * @param conn Connection object
+ * @param oobd_local Local OOB data or NULL if not set
+ * @param oobd_remote Remote OOB data or NULL if not set
+ *
+ *  @return Zero on success or error code otherwise, positive in case
+ *  of protocol error or negative (POSIX) in case of stack internal error
+ */
+int bt_le_oob_get_sc_data(struct bt_conn *conn,
+			  const struct bt_le_oob_sc_data **oobd_local,
+			  const struct bt_le_oob_sc_data **oobd_remote);
+
 /** @def BT_PASSKEY_INVALID
  *
  *  Special passkey value that can be used to disable a previously
@@ -435,6 +488,38 @@ void bt_set_bondable(bool enable);
  */
 int bt_passkey_set(unsigned int passkey);
 
+/** Info Structure for OOB pairing */
+struct bt_conn_oob_info {
+	/** Type of OOB pairing method */
+	enum {
+		/** LE legacy pairing */
+		BT_CONN_OOB_LE_LEGACY,
+
+		/** LE SC pairing */
+		BT_CONN_OOB_LE_SC,
+	} type;
+
+	union {
+		/** LESC OOB pairing parameters */
+		struct {
+			/** OOB data configuration */
+			enum {
+				/** Local OOB data requested */
+				BT_CONN_OOB_LOCAL_ONLY,
+
+				/** Remote OOB data requested */
+				BT_CONN_OOB_REMOTE_ONLY,
+
+				/** Both local and remote OOB data requested */
+				BT_CONN_OOB_BOTH_PEERS,
+
+				/** No OOB data requested */
+				BT_CONN_OOB_NO_DATA,
+			} oob_config;
+		} lesc;
+	};
+};
+
 /** Authenticated pairing callback structure */
 struct bt_conn_auth_cb {
 	/** @brief Display a passkey to the user.
@@ -500,6 +585,24 @@ struct bt_conn_auth_cb {
 	 */
 	void (*passkey_confirm)(struct bt_conn *conn, unsigned int passkey);
 
+	/** @brief Request the user to provide OOB data.
+	 *
+	 *  When called the user is expected to provide OOB data. The required
+	 *  data are indicated by the information structure.
+	 *
+	 *  For LESC OOB pairing method, the user should provide local OOB data,
+	 *  remote OOB data or both depending on their availability. Their value
+	 *  should be given to the stack using the bt_le_oob_set_sc_data() API.
+	 *
+	 *  This callback must be set to non-NULL in order to support OOB
+	 *  pairing.
+	 *
+	 *  @param conn Connection where pairing is currently active.
+	 *  @param info OOB pairing information.
+	 */
+	void (*oob_data_request)(struct bt_conn *conn,
+				 struct bt_conn_oob_info *info);
+
 	/** @brief Cancel the ongoing user request.
 	 *
 	 *  This callback will be called to notify the application that it