simmel-bootloader/nRF5_SDK_11.0.0_89a8197/components/ble/ble_services/ble_dfu/ble_dfu.c

650 lines
22 KiB
C

/* Copyright (c) 2013 Nordic Semiconductor. All Rights Reserved.
*
* The information contained herein is property of Nordic Semiconductor ASA.
* Terms and conditions of usage are described in detail in NORDIC
* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
*
* Licensees are granted free, non-transferable use of the information. NO
* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
* the file.
*
*/
#include "ble_dfu.h"
#include "ble_types.h"
#include "ble_gatts.h"
#include "ble_srv_common.h"
#include <stddef.h>
#include "sdk_common.h"
#define MAX_DFU_PKT_LEN 20 /**< Maximum length (in bytes) of the DFU Packet characteristic. */
#define PKT_START_DFU_PARAM_LEN 2 /**< Length (in bytes) of the parameters for Packet Start DFU Request. */
#define PKT_INIT_DFU_PARAM_LEN 2 /**< Length (in bytes) of the parameters for Packet Init DFU Request. */
#define PKT_RCPT_NOTIF_REQ_LEN 3 /**< Length (in bytes) of the Packet Receipt Notification Request. */
#define MAX_PKTS_RCPT_NOTIF_LEN 6 /**< Maximum length (in bytes) of the Packets Receipt Notification. */
#define MAX_RESPONSE_LEN 7 /**< Maximum length (in bytes) of the response to a Control Point command. */
#define MAX_NOTIF_BUFFER_LEN MAX(MAX_PKTS_RCPT_NOTIF_LEN, MAX_RESPONSE_LEN) /**< Maximum length (in bytes) of the buffer needed by DFU Service while sending notifications to peer. */
enum
{
OP_CODE_START_DFU = 1, /**< Value of the Op code field for 'Start DFU' command.*/
OP_CODE_RECEIVE_INIT = 2, /**< Value of the Op code field for 'Initialize DFU parameters' command.*/
OP_CODE_RECEIVE_FW = 3, /**< Value of the Op code field for 'Receive firmware image' command.*/
OP_CODE_VALIDATE = 4, /**< Value of the Op code field for 'Validate firmware' command.*/
OP_CODE_ACTIVATE_N_RESET = 5, /**< Value of the Op code field for 'Activate & Reset' command.*/
OP_CODE_SYS_RESET = 6, /**< Value of the Op code field for 'Reset System' command.*/
OP_CODE_IMAGE_SIZE_REQ = 7, /**< Value of the Op code field for 'Report received image size' command.*/
OP_CODE_PKT_RCPT_NOTIF_REQ = 8, /**< Value of the Op code field for 'Request packet receipt notification.*/
OP_CODE_RESPONSE = 16, /**< Value of the Op code field for 'Response.*/
OP_CODE_PKT_RCPT_NOTIF = 17 /**< Value of the Op code field for 'Packets Receipt Notification'.*/
};
static bool m_is_dfu_service_initialized = false; /**< Variable to check if the DFU service was initialized by the application.*/
static uint8_t m_notif_buffer[MAX_NOTIF_BUFFER_LEN]; /**< Buffer used for sending notifications to peer. */
/**@brief Function for adding DFU Packet characteristic to the BLE Stack.
*
* @param[in] p_dfu DFU Service structure.
*
* @return NRF_SUCCESS on success. Otherwise an error code.
*/
static uint32_t dfu_pkt_char_add(ble_dfu_t * const p_dfu)
{
ble_gatts_char_md_t char_md;
ble_gatts_attr_t attr_char_value;
ble_uuid_t char_uuid;
ble_gatts_attr_md_t attr_md;
memset(&char_md, 0, sizeof(char_md));
char_md.char_props.write_wo_resp = 1;
char_md.p_char_user_desc = NULL;
char_md.p_char_pf = NULL;
char_md.p_user_desc_md = NULL;
char_md.p_cccd_md = NULL;
char_md.p_sccd_md = NULL;
char_uuid.type = p_dfu->uuid_type;
char_uuid.uuid = BLE_DFU_PKT_CHAR_UUID;
memset(&attr_md, 0, sizeof(attr_md));
BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&attr_md.read_perm);
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);
attr_md.vloc = BLE_GATTS_VLOC_STACK;
attr_md.rd_auth = 0;
attr_md.wr_auth = 0;
attr_md.vlen = 1;
memset(&attr_char_value, 0, sizeof(attr_char_value));
attr_char_value.p_uuid = &char_uuid;
attr_char_value.p_attr_md = &attr_md;
attr_char_value.init_len = 0;
attr_char_value.init_offs = 0;
attr_char_value.max_len = MAX_DFU_PKT_LEN;
attr_char_value.p_value = NULL;
return sd_ble_gatts_characteristic_add(p_dfu->service_handle,
&char_md,
&attr_char_value,
&p_dfu->dfu_pkt_handles);
}
/**@brief Function for adding DFU Revision characteristic to the BLE Stack.
*
* @param[in] p_dfu DFU Service structure.
*
* @return NRF_SUCCESS on success. Otherwise an error code.
*/
static uint32_t dfu_rev_char_add(ble_dfu_t * const p_dfu, ble_dfu_init_t const * const p_dfu_init)
{
ble_gatts_char_md_t char_md;
ble_gatts_attr_t attr_char_value;
ble_uuid_t char_uuid;
ble_gatts_attr_md_t attr_md;
memset(&char_md, 0, sizeof(char_md));
char_md.char_props.read = 1;
char_md.p_char_user_desc = NULL;
char_md.p_char_pf = NULL;
char_md.p_user_desc_md = NULL;
char_md.p_cccd_md = NULL;
char_md.p_sccd_md = NULL;
char_uuid.type = p_dfu->uuid_type;
char_uuid.uuid = BLE_DFU_REV_CHAR_UUID;
memset(&attr_md, 0, sizeof(attr_md));
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&attr_md.write_perm);
attr_md.vloc = BLE_GATTS_VLOC_STACK;
attr_md.rd_auth = 0;
attr_md.wr_auth = 0;
attr_md.vlen = 1;
memset(&attr_char_value, 0, sizeof(attr_char_value));
attr_char_value.p_uuid = &char_uuid;
attr_char_value.p_attr_md = &attr_md;
attr_char_value.init_len = sizeof(uint16_t);
attr_char_value.init_offs = 0;
attr_char_value.max_len = sizeof(uint16_t);
attr_char_value.p_value = (uint8_t *)&p_dfu_init->revision;
return sd_ble_gatts_characteristic_add(p_dfu->service_handle,
&char_md,
&attr_char_value,
&p_dfu->dfu_rev_handles);
}
/**@brief Function for adding DFU Control Point characteristic to the BLE Stack.
*
* @param[in] p_dfu DFU Service structure.
*
* @return NRF_SUCCESS on success. Otherwise an error code.
*/
static uint32_t dfu_ctrl_pt_add(ble_dfu_t * const p_dfu)
{
ble_gatts_char_md_t char_md;
ble_gatts_attr_t attr_char_value;
ble_uuid_t char_uuid;
ble_gatts_attr_md_t attr_md;
memset(&char_md, 0, sizeof(char_md));
char_md.char_props.write = 1;
char_md.char_props.notify = 1;
char_md.p_char_user_desc = NULL;
char_md.p_char_pf = NULL;
char_md.p_user_desc_md = NULL;
char_md.p_cccd_md = NULL;
char_md.p_sccd_md = NULL;
char_uuid.type = p_dfu->uuid_type;
char_uuid.uuid = BLE_DFU_CTRL_PT_UUID;
memset(&attr_md, 0, sizeof(attr_md));
BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&attr_md.read_perm);
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);
attr_md.vloc = BLE_GATTS_VLOC_STACK;
attr_md.rd_auth = 0;
attr_md.wr_auth = 1;
attr_md.vlen = 1;
memset(&attr_char_value, 0, sizeof(attr_char_value));
attr_char_value.p_uuid = &char_uuid;
attr_char_value.p_attr_md = &attr_md;
attr_char_value.init_len = 0;
attr_char_value.init_offs = 0;
attr_char_value.max_len = BLE_GATT_ATT_MTU_DEFAULT;
attr_char_value.p_value = NULL;
return sd_ble_gatts_characteristic_add(p_dfu->service_handle,
&char_md,
&attr_char_value,
&p_dfu->dfu_ctrl_pt_handles);
}
/**@brief Function for handling the @ref BLE_GAP_EVT_CONNECTED event from the S110 SoftDevice.
*
* @param[in] p_dfu DFU Service Structure.
* @param[in] p_ble_evt Pointer to the event received from BLE stack.
*/
static void on_connect(ble_dfu_t * p_dfu, ble_evt_t * p_ble_evt)
{
p_dfu->conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
}
/**@brief Function for checking if the CCCD of DFU Control point is configured for Notification.
*
* @details This function checks if the CCCD of DFU Control Point characteristic is configured
* for Notification by the DFU Controller.
*
* @param[in] p_dfu DFU Service structure.
*
* @return True if the CCCD of DFU Control Point characteristic is configured for Notification.
* False otherwise.
*/
static bool is_cccd_configured(ble_dfu_t * p_dfu)
{
// Check if the CCCDs are configured.
uint8_t cccd_val_buf[BLE_CCCD_VALUE_LEN];
ble_gatts_value_t gatts_value;
// Initialize value struct.
memset(&gatts_value, 0, sizeof(gatts_value));
gatts_value.len = BLE_CCCD_VALUE_LEN;
gatts_value.offset = 0;
gatts_value.p_value = cccd_val_buf;
// Check the CCCD Value of DFU Control Point.
uint32_t err_code = sd_ble_gatts_value_get(p_dfu->conn_handle,
p_dfu->dfu_ctrl_pt_handles.cccd_handle,
&gatts_value);
if (err_code != NRF_SUCCESS)
{
if (p_dfu->error_handler != NULL)
{
p_dfu->error_handler(err_code);
}
return false;
}
return ble_srv_is_notification_enabled(cccd_val_buf);
}
/**@brief Function for handling a Write event on the Control Point characteristic.
*
* @param[in] p_dfu DFU Service Structure.
* @param[in] p_ble_write_evt Pointer to the write event received from BLE stack.
*
* @return NRF_SUCCESS on successful processing of control point write. Otherwise an error code.
*/
static uint32_t on_ctrl_pt_write(ble_dfu_t * p_dfu, ble_gatts_evt_write_t * p_ble_write_evt)
{
ble_gatts_rw_authorize_reply_params_t auth_reply;
auth_reply.type = BLE_GATTS_AUTHORIZE_TYPE_WRITE;
auth_reply.type = BLE_GATTS_AUTHORIZE_TYPE_WRITE;
auth_reply.params.write.update = 1;
auth_reply.params.write.offset = p_ble_write_evt->offset;
auth_reply.params.write.len = p_ble_write_evt->len;
auth_reply.params.write.p_data = p_ble_write_evt->data;
if (!is_cccd_configured(p_dfu))
{
// Send an error response to the peer indicating that the CCCD is improperly configured.
auth_reply.params.write.gatt_status =
BLE_GATT_STATUS_ATTERR_CPS_CCCD_CONFIG_ERROR;
return (sd_ble_gatts_rw_authorize_reply(p_dfu->conn_handle, &auth_reply));
}
else
{
uint32_t err_code;
auth_reply.params.write.gatt_status = BLE_GATT_STATUS_SUCCESS;
err_code = (sd_ble_gatts_rw_authorize_reply(p_dfu->conn_handle, &auth_reply));
VERIFY_SUCCESS(err_code);
}
ble_dfu_evt_t ble_dfu_evt;
switch (p_ble_write_evt->data[0])
{
case OP_CODE_START_DFU:
ble_dfu_evt.ble_dfu_evt_type = BLE_DFU_START;
if (p_ble_write_evt->len < PKT_START_DFU_PARAM_LEN)
{
return ble_dfu_response_send(p_dfu,
(ble_dfu_procedure_t) p_ble_write_evt->data[0],
BLE_DFU_RESP_VAL_OPER_FAILED);
}
ble_dfu_evt.evt.ble_dfu_pkt_write.len = 1;
ble_dfu_evt.evt.ble_dfu_pkt_write.p_data = &(p_ble_write_evt->data[1]);
p_dfu->evt_handler(p_dfu, &ble_dfu_evt);
break;
case OP_CODE_RECEIVE_INIT:
ble_dfu_evt.ble_dfu_evt_type = BLE_DFU_RECEIVE_INIT_DATA;
if (p_ble_write_evt->len < PKT_INIT_DFU_PARAM_LEN)
{
return ble_dfu_response_send(p_dfu,
(ble_dfu_procedure_t) p_ble_write_evt->data[0],
BLE_DFU_RESP_VAL_OPER_FAILED);
}
ble_dfu_evt.evt.ble_dfu_pkt_write.len = 1;
ble_dfu_evt.evt.ble_dfu_pkt_write.p_data = &(p_ble_write_evt->data[1]);
p_dfu->evt_handler(p_dfu, &ble_dfu_evt);
break;
case OP_CODE_RECEIVE_FW:
ble_dfu_evt.ble_dfu_evt_type = BLE_DFU_RECEIVE_APP_DATA;
p_dfu->evt_handler(p_dfu, &ble_dfu_evt);
break;
case OP_CODE_VALIDATE:
ble_dfu_evt.ble_dfu_evt_type = BLE_DFU_VALIDATE;
p_dfu->evt_handler(p_dfu, &ble_dfu_evt);
break;
case OP_CODE_ACTIVATE_N_RESET:
ble_dfu_evt.ble_dfu_evt_type = BLE_DFU_ACTIVATE_N_RESET;
p_dfu->evt_handler(p_dfu, &ble_dfu_evt);
break;
case OP_CODE_SYS_RESET:
ble_dfu_evt.ble_dfu_evt_type = BLE_DFU_SYS_RESET;
p_dfu->evt_handler(p_dfu, &ble_dfu_evt);
break;
case OP_CODE_PKT_RCPT_NOTIF_REQ:
if (p_ble_write_evt->len < PKT_RCPT_NOTIF_REQ_LEN)
{
return (ble_dfu_response_send(p_dfu,
BLE_DFU_PKT_RCPT_REQ_PROCEDURE,
BLE_DFU_RESP_VAL_NOT_SUPPORTED));
}
ble_dfu_evt.evt.pkt_rcpt_notif_req.num_of_pkts =
uint16_decode(&(p_ble_write_evt->data[1]));
if (ble_dfu_evt.evt.pkt_rcpt_notif_req.num_of_pkts == 0)
{
ble_dfu_evt.ble_dfu_evt_type = BLE_DFU_PKT_RCPT_NOTIF_DISABLED;
}
else
{
ble_dfu_evt.ble_dfu_evt_type = BLE_DFU_PKT_RCPT_NOTIF_ENABLED;
}
p_dfu->evt_handler(p_dfu, &ble_dfu_evt);
break;
case OP_CODE_IMAGE_SIZE_REQ:
ble_dfu_evt.ble_dfu_evt_type = BLE_DFU_BYTES_RECEIVED_SEND;
p_dfu->evt_handler(p_dfu, &ble_dfu_evt);
break;
default:
// Unsupported op code.
return ble_dfu_response_send(p_dfu,
(ble_dfu_procedure_t) p_ble_write_evt->data[0],
BLE_DFU_RESP_VAL_NOT_SUPPORTED);
}
return NRF_SUCCESS;
}
/**@brief Function for handling the @ref BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST event from the S110
* Stack.
*
* @param[in] p_dfu DFU Service Structure.
* @param[in] p_ble_evt Pointer to the event received from BLE stack.
*/
static void on_rw_authorize_req(ble_dfu_t * p_dfu, ble_evt_t * p_ble_evt)
{
ble_gatts_evt_rw_authorize_request_t * p_authorize_request;
p_authorize_request = &(p_ble_evt->evt.gatts_evt.params.authorize_request);
if (
(p_authorize_request->type == BLE_GATTS_AUTHORIZE_TYPE_WRITE)
&&
(p_authorize_request->request.write.handle == p_dfu->dfu_ctrl_pt_handles.value_handle)
&&
(p_ble_evt->evt.gatts_evt.params.authorize_request.request.write.op != BLE_GATTS_OP_PREP_WRITE_REQ)
&&
(p_ble_evt->evt.gatts_evt.params.authorize_request.request.write.op != BLE_GATTS_OP_EXEC_WRITE_REQ_NOW)
&&
(p_ble_evt->evt.gatts_evt.params.authorize_request.request.write.op != BLE_GATTS_OP_EXEC_WRITE_REQ_CANCEL)
)
{
uint32_t err_code;
err_code = on_ctrl_pt_write(p_dfu, &(p_authorize_request->request.write));
if (err_code != NRF_SUCCESS && p_dfu->error_handler != NULL)
{
p_dfu->error_handler(err_code);
}
}
}
/**@brief Function for handling the @ref BLE_GATTS_EVT_WRITE event from the S110 SoftDevice.
*
* @param[in] p_dfu DFU Service Structure.
* @param[in] p_ble_evt Pointer to the event received from BLE stack.
*/
static void on_write(ble_dfu_t * p_dfu, ble_evt_t * p_ble_evt)
{
if (p_ble_evt->evt.gatts_evt.params.write.handle == p_dfu->dfu_pkt_handles.value_handle)
{
// DFU Packet written
ble_dfu_evt_t ble_dfu_evt;
ble_dfu_evt.ble_dfu_evt_type = BLE_DFU_PACKET_WRITE;
ble_dfu_evt.evt.ble_dfu_pkt_write.len = p_ble_evt->evt.gatts_evt.params.write.len;
ble_dfu_evt.evt.ble_dfu_pkt_write.p_data = p_ble_evt->evt.gatts_evt.params.write.data;
p_dfu->evt_handler(p_dfu, &ble_dfu_evt);
}
}
/**@brief Function for handling the BLE_GAP_EVT_DISCONNECTED event from the S110 SoftDevice.
*
* @param[in] p_dfu DFU Service Structure.
* @param[in] p_ble_evt Pointer to the event received from BLE stack.
*/
static void on_disconnect(ble_dfu_t * p_dfu, ble_evt_t * p_ble_evt)
{
p_dfu->conn_handle = BLE_CONN_HANDLE_INVALID;
}
uint32_t ble_dfu_init(ble_dfu_t * p_dfu, ble_dfu_init_t * p_dfu_init)
{
if ((p_dfu == NULL) || (p_dfu_init == NULL) || (p_dfu_init->evt_handler == NULL))
{
return NRF_ERROR_NULL;
}
p_dfu->conn_handle = BLE_CONN_HANDLE_INVALID;
ble_uuid_t service_uuid;
uint32_t err_code;
const ble_uuid128_t base_uuid128 =
{
{
0x23, 0xD1, 0xBC, 0xEA, 0x5F, 0x78, 0x23, 0x15,
0xDE, 0xEF, 0x12, 0x12, 0x00, 0x00, 0x00, 0x00
}
};
service_uuid.uuid = BLE_DFU_SERVICE_UUID;
err_code = sd_ble_uuid_vs_add(&base_uuid128, &(service_uuid.type));
VERIFY_SUCCESS(err_code);
err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
&service_uuid,
&(p_dfu->service_handle));
VERIFY_SUCCESS(err_code);
p_dfu->uuid_type = service_uuid.type;
err_code = dfu_pkt_char_add(p_dfu);
VERIFY_SUCCESS(err_code);
err_code = dfu_ctrl_pt_add(p_dfu);
VERIFY_SUCCESS(err_code);
err_code = dfu_rev_char_add(p_dfu, p_dfu_init);
VERIFY_SUCCESS(err_code);
p_dfu->evt_handler = p_dfu_init->evt_handler;
if (p_dfu_init->error_handler != NULL)
{
p_dfu->error_handler = p_dfu_init->error_handler;
}
m_is_dfu_service_initialized = true;
return NRF_SUCCESS;
}
void ble_dfu_on_ble_evt(ble_dfu_t * p_dfu, ble_evt_t * p_ble_evt)
{
if ((p_dfu == NULL) || (p_ble_evt == NULL))
{
return;
}
if (p_dfu->evt_handler != NULL)
{
switch (p_ble_evt->header.evt_id)
{
case BLE_GAP_EVT_CONNECTED:
on_connect(p_dfu, p_ble_evt);
break;
case BLE_GATTS_EVT_WRITE:
on_write(p_dfu, p_ble_evt);
break;
case BLE_GAP_EVT_DISCONNECTED:
on_disconnect(p_dfu, p_ble_evt);
break;
case BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST:
on_rw_authorize_req(p_dfu, p_ble_evt);
break;
default:
// No implementation needed.
break;
}
}
}
uint32_t ble_dfu_bytes_rcvd_report(ble_dfu_t * p_dfu, uint32_t num_of_firmware_bytes_rcvd)
{
if (p_dfu == NULL)
{
return NRF_ERROR_NULL;
}
if ((p_dfu->conn_handle == BLE_CONN_HANDLE_INVALID) || !m_is_dfu_service_initialized)
{
return NRF_ERROR_INVALID_STATE;
}
ble_gatts_hvx_params_t hvx_params;
uint16_t index = 0;
// Encode the Op Code.
m_notif_buffer[index++] = OP_CODE_RESPONSE;
// Encode the Reqest Op Code.
m_notif_buffer[index++] = OP_CODE_IMAGE_SIZE_REQ;
// Encode the Response Value.
m_notif_buffer[index++] = (uint8_t)BLE_DFU_RESP_VAL_SUCCESS;
index += uint32_encode(num_of_firmware_bytes_rcvd, &m_notif_buffer[index]);
memset(&hvx_params, 0, sizeof(hvx_params));
hvx_params.handle = p_dfu->dfu_ctrl_pt_handles.value_handle;
hvx_params.type = BLE_GATT_HVX_NOTIFICATION;
hvx_params.offset = 0;
hvx_params.p_len = &index;
hvx_params.p_data = m_notif_buffer;
return sd_ble_gatts_hvx(p_dfu->conn_handle, &hvx_params);
}
uint32_t ble_dfu_pkts_rcpt_notify(ble_dfu_t * p_dfu, uint32_t num_of_firmware_bytes_rcvd)
{
if (p_dfu == NULL)
{
return NRF_ERROR_NULL;
}
if ((p_dfu->conn_handle == BLE_CONN_HANDLE_INVALID) || !m_is_dfu_service_initialized)
{
return NRF_ERROR_INVALID_STATE;
}
ble_gatts_hvx_params_t hvx_params;
uint16_t index = 0;
m_notif_buffer[index++] = OP_CODE_PKT_RCPT_NOTIF;
index += uint32_encode(num_of_firmware_bytes_rcvd, &m_notif_buffer[index]);
memset(&hvx_params, 0, sizeof(hvx_params));
hvx_params.handle = p_dfu->dfu_ctrl_pt_handles.value_handle;
hvx_params.type = BLE_GATT_HVX_NOTIFICATION;
hvx_params.offset = 0;
hvx_params.p_len = &index;
hvx_params.p_data = m_notif_buffer;
return sd_ble_gatts_hvx(p_dfu->conn_handle, &hvx_params);
}
uint32_t ble_dfu_response_send(ble_dfu_t * p_dfu,
ble_dfu_procedure_t dfu_proc,
ble_dfu_resp_val_t resp_val)
{
if (p_dfu == NULL)
{
return NRF_ERROR_NULL;
}
if ((p_dfu->conn_handle == BLE_CONN_HANDLE_INVALID) || !m_is_dfu_service_initialized)
{
return NRF_ERROR_INVALID_STATE;
}
ble_gatts_hvx_params_t hvx_params;
uint16_t index = 0;
m_notif_buffer[index++] = OP_CODE_RESPONSE;
// Encode the Request Op code
m_notif_buffer[index++] = (uint8_t)dfu_proc;
// Encode the Response Value.
m_notif_buffer[index++] = (uint8_t)resp_val;
memset(&hvx_params, 0, sizeof(hvx_params));
hvx_params.handle = p_dfu->dfu_ctrl_pt_handles.value_handle;
hvx_params.type = BLE_GATT_HVX_NOTIFICATION;
hvx_params.offset = 0;
hvx_params.p_len = &index;
hvx_params.p_data = m_notif_buffer;
return sd_ble_gatts_hvx(p_dfu->conn_handle, &hvx_params);
}