nRF52832 BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM failed

[Max Liao]

Hi,

I got a problem that when I try to use BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM for characteristic.

As I follow the tutorial to create the custom service, when I changed "BLE_GAP_CONN_SEC_MODE_SET_OPEN" to "BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM" then the application run failed and show fatal error.

Is there any point that I miss it ? Or how to create the characteristic with encryption correctly ?

I used SDK v15 BTY.

Thanks.

[Einar Thorsrud]

Hi,

Can you be more specific to what error you get? The simplest way to see where it fails and with what error code is to enable/define DEBUG and logging. Then you should see which file and line number the error is caught, and what the error code was.

[Max Liao]

Hi Einar Thorsrud

Sorry, the error code is 7.

I follow the custom service to build my own service, but in this tutorial using the OPEN characteristic.

But I want to use the encryption character, so follow the final step in Step6 in tutorial to set "BLE_GAP_CONN_SEC_MODE_SET_OPEN", and change it to "BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM"  in main.c, then I got the error.

[Einar Thorsrud]

I see. 7 is NRF_ERROR_INVALID_PARAM. From which function do you get that returned?

[Max Liao]

Hi Einar Thorsrud

Sorry for the late reply, I was deal with another task.

I got it when I called service init from main.c file.

here's my code

// In main.c
static void btp_info_initiate(void) {
    ret_code_t     err_code;
    btp_info_init_t info_init;

    memset(&info_init, 0, sizeof(info_init));

    BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM(&info_init.btp_info_value_char_attr_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM(&info_init.btp_info_value_char_attr_md.write_perm);

    //BLE_GAP_CONN_SEC_MODE_SET_OPEN(&info_init.btp_info_value_char_attr_md.read_perm);
    //BLE_GAP_CONN_SEC_MODE_SET_OPEN(&info_init.btp_info_value_char_attr_md.write_perm);

    info_init.evt_handler = btp_info_evt;

    err_code = btp_info_init(&btp_info, &info_init);  // err_code return 7 on this line
    APP_ERROR_CHECK(err_code);
}

P.S This function will be call in service_init in main.c

Then I trace with error, see the error code will return 7 when called btp_info_init function.

// In cus_srv.c
ret_code_t btp_info_init(btp_info_t * p_info, const btp_info_init_t * p_info_init) {

    if (p_info == NULL || p_info_init == NULL)
        return NRF_ERROR_NULL;

    ret_code_t err_code;
    ble_uuid_t ble_uuid;

    p_info->evt_handler = p_info_init->evt_handler;
    p_info->conn_handle = BLE_CONN_HANDLE_INVALID;

    // Add BTP Info Service UUID
    ble_uuid128_t base_uuid = {BTP_INFO_SERVICE_BASE};
    err_code = sd_ble_uuid_vs_add(&base_uuid, &p_info->uuid_type);
    VERIFY_SUCCESS(err_code);

    // Add BTP Info Service
    ble_uuid.type = p_info->uuid_type;
    ble_uuid.uuid = BTP_UUID_INFO_SERVICE;

    err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY, &ble_uuid, &p_info->service_handle);
    if(err_code != NRF_SUCCESS)
        return err_code;
    
    err_code = btp_info_trek_stat_char_add(p_info, p_info_init);
    VERIFY_SUCCESS(err_code);
}

And I keep trace into it, I see the error comes from btp_info_trek_stat_char_add function

static uint32_t btp_info_trek_stat_char_add(btp_info_t * p_info, const btp_info_init_t * p_info_init) {
    ble_uuid_t          ble_uuid;
    ble_gatts_char_md_t char_md;
    ble_gatts_attr_md_t attr_md;
    ble_gatts_attr_t    attr_char_value;

    // The ble_gatts_char_md_t structure uses bit fields. So we reset the memory to zero.
    memset(&char_md, 0, sizeof(char_md));

    char_md.char_props.write = 0;
    char_md.char_props.read  = 1;
    char_md.char_props.notify = 1;
    char_md.p_char_pf = NULL;
    char_md.p_cccd_md = &attr_md;
    char_md.p_sccd_md = NULL;
    char_md.p_user_desc_md = NULL;

    memset(&attr_md, 0, sizeof(attr_md));

    attr_md.read_perm  = p_info_init->btp_info_value_char_attr_md.read_perm;
    attr_md.write_perm = p_info_init->btp_info_value_char_attr_md.write_perm;
    attr_md.vloc       = BLE_GATTS_VLOC_STACK;
    attr_md.rd_auth    = 0;
    attr_md.wr_auth    = 0;
    attr_md.vlen       = 0;

    uint32_t err_code;
    ble_uuid128_t base_uuid = BTP_INFO_TRACKING_STAT_BASE;
    ble_uuid.uuid = BTP_UUID_INFO_TRACKING_STAT;
    err_code = sd_ble_uuid_vs_add(&base_uuid, &ble_uuid.type);
    LOG_INFO("err_code: %d", err_code);
    APP_ERROR_CHECK(err_code);  

    memset(&attr_char_value, 0, sizeof(attr_char_value));

    attr_char_value.p_uuid    = &ble_uuid;
    attr_char_value.p_attr_md = &attr_md;
    attr_char_value.init_len  = sizeof(uint8_t);
    attr_char_value.init_offs = 0;
    attr_char_value.max_len   = sizeof(uint8_t);
    //attr_char_value.p_value   = p_char_value;

    return sd_ble_gatts_characteristic_add(p_info->service_handle, &char_md,
                                           &attr_char_value,
                                           &p_info->btp_info_trek_stat_handles);
}

And in final the error comes from the sd_ble_gatts_characteristic_add function.

So is there something that I miss?

[Einar Thorsrud]

I see,

So you get the NRF_ERROR_INVALID_PARAM return code from the call to sd_ble_gatts_characteristic_add(). From the API documentation, this indicate that

Invalid parameter(s) supplied, service handle, Vendor Specific UUIDs, lengths, and permissions need to adhere to the constraints.

I do not immediately see the exact problem, though.