esp-nimble-cpp/src/NimBLEUtils.cpp

/*
 * NimBLEUtils.cpp
 *
 *  Created: on Jan 25 2020
 *      Author H2zero
 *
 */

#include "nimconfig.h"
#if defined(CONFIG_BT_ENABLED)

#include "NimBLEUtils.h"
#include "NimBLELog.h"
#include "nimconfig.h"

static const char* LOG_TAG = "NimBLEUtils";


/**
 * @brief A function for checking validity of connection parameters.
 * @param [in] params A pointer to the structure containing the parameters to check.
 * @return valid == 0 or error code.
 */
int NimBLEUtils::checkConnParams(ble_gap_conn_params* params) {
    /* Check connection interval min */
    if ((params->itvl_min < BLE_HCI_CONN_ITVL_MIN) ||
        (params->itvl_min > BLE_HCI_CONN_ITVL_MAX)) {
        return BLE_ERR_INV_HCI_CMD_PARMS;
    }
    /* Check connection interval max */
    if ((params->itvl_max < BLE_HCI_CONN_ITVL_MIN) ||
        (params->itvl_max > BLE_HCI_CONN_ITVL_MAX) ||
        (params->itvl_max < params->itvl_min)) {
        return BLE_ERR_INV_HCI_CMD_PARMS;
    }

    /* Check connection latency */
    if (params->latency > BLE_HCI_CONN_LATENCY_MAX) {
        return BLE_ERR_INV_HCI_CMD_PARMS;
    }

    /* Check supervision timeout */
    if ((params->supervision_timeout < BLE_HCI_CONN_SPVN_TIMEOUT_MIN) ||
        (params->supervision_timeout > BLE_HCI_CONN_SPVN_TIMEOUT_MAX)) {
        return BLE_ERR_INV_HCI_CMD_PARMS;
    }

    /* Check connection event length */
    if (params->min_ce_len > params->max_ce_len) {
        return BLE_ERR_INV_HCI_CMD_PARMS;
    }

    return 0;
}


/**
 * @brief Converts a return code from the NimBLE stack to a text string.
 * @param [in] rc The return code to convert.
 * @return A string representation of the return code.
 */
const char* NimBLEUtils::returnCodeToString(int rc) {
#if defined(CONFIG_NIMBLE_CPP_ENABLE_RETURN_CODE_TEXT)
    switch(rc) {
        case 0:
            return "SUCCESS";
        case BLE_HS_EAGAIN:
            return "Temporary failure; try again.";
        case BLE_HS_EALREADY:
            return "Operation already in progress or completed.";
        case BLE_HS_EINVAL:
            return "One or more arguments are invalid.";
        case BLE_HS_EMSGSIZE:
            return "The provided buffer is too small.";
        case BLE_HS_ENOENT:
            return "No entry matching the specified criteria.";
        case BLE_HS_ENOMEM:
            return "Operation failed due to resource exhaustion.";
        case BLE_HS_ENOTCONN:
            return "No open connection with the specified handle.";
        case BLE_HS_ENOTSUP:
            return "Operation disabled at compile time.";
        case BLE_HS_EAPP:
            return "Application callback behaved unexpectedly.";
        case BLE_HS_EBADDATA:
            return "Command from peer is invalid.";
        case BLE_HS_EOS:
            return "Mynewt OS error.";
        case BLE_HS_ECONTROLLER:
            return "Event from controller is invalid.";
        case BLE_HS_ETIMEOUT:
            return "Operation timed out.";
        case BLE_HS_EDONE:
            return "Operation completed successfully.";
        case BLE_HS_EBUSY:
            return "Operation cannot be performed until procedure completes.";
        case BLE_HS_EREJECT:
            return "Peer rejected a connection parameter update request.";
        case BLE_HS_EUNKNOWN:
            return "Unexpected failure; catch all.";
        case BLE_HS_EROLE:
            return "Operation requires different role (e.g., central vs. peripheral).";
        case BLE_HS_ETIMEOUT_HCI:
            return "HCI request timed out; controller unresponsive.";
        case BLE_HS_ENOMEM_EVT:
            return "Controller failed to send event due to memory exhaustion (combined host-controller only).";
        case BLE_HS_ENOADDR:
            return "Operation requires an identity address but none configured.";
        case BLE_HS_ENOTSYNCED:
            return "Attempt to use the host before it is synced with controller.";
        case BLE_HS_EAUTHEN:
            return "Insufficient authentication.";
        case BLE_HS_EAUTHOR:
            return "Insufficient authorization.";
        case BLE_HS_EENCRYPT:
            return "Insufficient encryption level.";
        case BLE_HS_EENCRYPT_KEY_SZ:
            return "Insufficient key size.";
        case BLE_HS_ESTORE_CAP:
            return "Storage at capacity.";
        case BLE_HS_ESTORE_FAIL:
            return "Storage IO error.";
        case  (0x0100+BLE_ATT_ERR_INVALID_HANDLE ):
            return "The attribute handle given was not valid on this server.";
        case  (0x0100+BLE_ATT_ERR_READ_NOT_PERMITTED ):
            return "The attribute cannot be read.";
        case  (0x0100+BLE_ATT_ERR_WRITE_NOT_PERMITTED ):
            return "The attribute cannot be written.";
        case  (0x0100+BLE_ATT_ERR_INVALID_PDU ):
            return "The attribute PDU was invalid.";
        case  (0x0100+BLE_ATT_ERR_INSUFFICIENT_AUTHEN ):
            return "The attribute requires authentication before it can be read or written.";
        case  (0x0100+BLE_ATT_ERR_REQ_NOT_SUPPORTED ):
            return "Attribute server does not support the request received from the client.";
        case  (0x0100+BLE_ATT_ERR_INVALID_OFFSET ):
            return "Offset specified was past the end of the attribute.";
        case  (0x0100+BLE_ATT_ERR_INSUFFICIENT_AUTHOR ):
            return "The attribute requires authorization before it can be read or written.";
        case  (0x0100+BLE_ATT_ERR_PREPARE_QUEUE_FULL ):
            return "Too many prepare writes have been queued.";
        case  (0x0100+BLE_ATT_ERR_ATTR_NOT_FOUND ):
            return "No attribute found within the given attribute handle range.";
        case  (0x0100+BLE_ATT_ERR_ATTR_NOT_LONG ):
            return "The attribute cannot be read or written using the Read Blob Request.";
        case  (0x0100+BLE_ATT_ERR_INSUFFICIENT_KEY_SZ ):
            return "The Encryption Key Size used for encrypting this link is insufficient.";
        case  (0x0100+BLE_ATT_ERR_INVALID_ATTR_VALUE_LEN ):
            return "The attribute value length is invalid for the operation.";
        case  (0x0100+BLE_ATT_ERR_UNLIKELY ):
            return "The attribute request has encountered an error that was unlikely, could not be completed as requested.";
        case  (0x0100+BLE_ATT_ERR_INSUFFICIENT_ENC ):
            return "The attribute requires encryption before it can be read or written.";
        case  (0x0100+BLE_ATT_ERR_UNSUPPORTED_GROUP ):
            return "The attribute type is not a supported grouping attribute as defined by a higher layer specification.";
        case  (0x0100+BLE_ATT_ERR_INSUFFICIENT_RES ):
            return "Insufficient Resources to complete the request.";
        case  (0x0200+BLE_ERR_UNKNOWN_HCI_CMD ):
            return "Unknown HCI Command";
        case  (0x0200+BLE_ERR_UNK_CONN_ID ):
            return "Unknown Connection Identifier";
        case  (0x0200+BLE_ERR_HW_FAIL ):
            return "Hardware Failure";
        case  (0x0200+BLE_ERR_PAGE_TMO ):
            return "Page Timeout";
        case  (0x0200+BLE_ERR_AUTH_FAIL ):
            return "Authentication Failure";
        case  (0x0200+BLE_ERR_PINKEY_MISSING ):
            return "PIN or Key Missing";
        case  (0x0200+BLE_ERR_MEM_CAPACITY ):
            return "Memory Capacity Exceeded";
        case  (0x0200+BLE_ERR_CONN_SPVN_TMO ):
            return "Connection Timeout";
        case  (0x0200+BLE_ERR_CONN_LIMIT ):
            return "Connection Limit Exceeded";
        case  (0x0200+BLE_ERR_SYNCH_CONN_LIMIT ):
            return "Synchronous Connection Limit To A Device Exceeded";
        case  (0x0200+BLE_ERR_ACL_CONN_EXISTS ):
            return "ACL Connection Already Exists";
        case  (0x0200+BLE_ERR_CMD_DISALLOWED ):
            return "Command Disallowed";
        case  (0x0200+BLE_ERR_CONN_REJ_RESOURCES ):
            return "Connection Rejected due to Limited Resources";
        case  (0x0200+BLE_ERR_CONN_REJ_SECURITY ):
            return "Connection Rejected Due To Security Reasons";
        case  (0x0200+BLE_ERR_CONN_REJ_BD_ADDR ):
            return "Connection Rejected due to Unacceptable BD_ADDR";
        case  (0x0200+BLE_ERR_CONN_ACCEPT_TMO ):
            return "Connection Accept Timeout Exceeded";
        case  (0x0200+BLE_ERR_UNSUPPORTED ):
            return "Unsupported Feature or Parameter Value";
        case  (0x0200+BLE_ERR_INV_HCI_CMD_PARMS ):
            return "Invalid HCI Command Parameters";
        case  (0x0200+BLE_ERR_REM_USER_CONN_TERM ):
            return "Remote User Terminated Connection";
        case  (0x0200+BLE_ERR_RD_CONN_TERM_RESRCS ):
            return "Remote Device Terminated Connection due to Low Resources";
        case  (0x0200+BLE_ERR_RD_CONN_TERM_PWROFF ):
            return "Remote Device Terminated Connection due to Power Off";
        case  (0x0200+BLE_ERR_CONN_TERM_LOCAL ):
            return "Connection Terminated By Local Host";
        case  (0x0200+BLE_ERR_REPEATED_ATTEMPTS ):
            return "Repeated Attempts";
        case  (0x0200+BLE_ERR_NO_PAIRING ):
            return "Pairing Not Allowed";
        case  (0x0200+BLE_ERR_UNK_LMP ):
            return "Unknown LMP PDU";
        case  (0x0200+BLE_ERR_UNSUPP_REM_FEATURE ):
            return "Unsupported Remote Feature / Unsupported LMP Feature";
        case  (0x0200+BLE_ERR_SCO_OFFSET ):
            return "SCO Offset Rejected";
        case  (0x0200+BLE_ERR_SCO_ITVL ):
            return "SCO Interval Rejected";
        case  (0x0200+BLE_ERR_SCO_AIR_MODE ):
            return "SCO Air Mode Rejected";
        case  (0x0200+BLE_ERR_INV_LMP_LL_PARM ):
            return "Invalid LMP Parameters / Invalid LL Parameters";
        case  (0x0200+BLE_ERR_UNSPECIFIED ):
            return "Unspecified Error";
        case  (0x0200+BLE_ERR_UNSUPP_LMP_LL_PARM ):
            return "Unsupported LMP Parameter Value / Unsupported LL Parameter Value";
        case  (0x0200+BLE_ERR_NO_ROLE_CHANGE ):
            return "Role Change Not Allowed";
        case  (0x0200+BLE_ERR_LMP_LL_RSP_TMO ):
            return "LMP Response Timeout / LL Response Timeout";
        case  (0x0200+BLE_ERR_LMP_COLLISION ):
            return "LMP Error Transaction Collision";
        case  (0x0200+BLE_ERR_LMP_PDU ):
            return "LMP PDU Not Allowed";
        case  (0x0200+BLE_ERR_ENCRYPTION_MODE ):
            return "Encryption Mode Not Acceptable";
        case  (0x0200+BLE_ERR_LINK_KEY_CHANGE ):
            return "Link Key cannot be Changed";
        case  (0x0200+BLE_ERR_UNSUPP_QOS ):
            return "Requested QoS Not Supported";
        case  (0x0200+BLE_ERR_INSTANT_PASSED ):
            return "Instant Passed";
        case  (0x0200+BLE_ERR_UNIT_KEY_PAIRING ):
            return "Pairing With Unit Key Not Supported";
        case  (0x0200+BLE_ERR_DIFF_TRANS_COLL ):
            return "Different Transaction Collision";
        case  (0x0200+BLE_ERR_QOS_PARM ):
            return "QoS Unacceptable Parameter";
        case  (0x0200+BLE_ERR_QOS_REJECTED ):
            return "QoS Rejected";
        case  (0x0200+BLE_ERR_CHAN_CLASS ):
            return "Channel Classification Not Supported";
        case  (0x0200+BLE_ERR_INSUFFICIENT_SEC ):
            return "Insufficient Security";
        case  (0x0200+BLE_ERR_PARM_OUT_OF_RANGE ):
            return "Parameter Out Of Mandatory Range";
        case  (0x0200+BLE_ERR_PENDING_ROLE_SW ):
            return "Role Switch Pending";
        case  (0x0200+BLE_ERR_RESERVED_SLOT ):
            return "Reserved Slot Violation";
        case  (0x0200+BLE_ERR_ROLE_SW_FAIL ):
            return "Role Switch Failed";
        case  (0x0200+BLE_ERR_INQ_RSP_TOO_BIG ):
            return "Extended Inquiry Response Too Large";
        case  (0x0200+BLE_ERR_SEC_SIMPLE_PAIR ):
            return "Secure Simple Pairing Not Supported By Host";
        case  (0x0200+BLE_ERR_HOST_BUSY_PAIR ):
            return "Host Busy - Pairing";
        case  (0x0200+BLE_ERR_CONN_REJ_CHANNEL ):
            return "Connection Rejected, No Suitable Channel Found";
        case  (0x0200+BLE_ERR_CTLR_BUSY ):
            return "Controller Busy";
        case  (0x0200+BLE_ERR_CONN_PARMS ):
            return "Unacceptable Connection Parameters";
        case  (0x0200+BLE_ERR_DIR_ADV_TMO ):
            return "Directed Advertising Timeout";
        case  (0x0200+BLE_ERR_CONN_TERM_MIC ):
            return "Connection Terminated due to MIC Failure";
        case  (0x0200+BLE_ERR_CONN_ESTABLISHMENT ):
            return "Connection Failed to be Established";
        case  (0x0200+BLE_ERR_MAC_CONN_FAIL ):
            return "MAC Connection Failed";
        case  (0x0200+BLE_ERR_COARSE_CLK_ADJ ):
            return "Coarse Clock Adjustment Rejected";
        case  (0x0300+BLE_L2CAP_SIG_ERR_CMD_NOT_UNDERSTOOD ):
            return "Invalid or unsupported incoming L2CAP sig command.";
        case  (0x0300+BLE_L2CAP_SIG_ERR_MTU_EXCEEDED ):
            return "Incoming packet too large.";
        case  (0x0300+BLE_L2CAP_SIG_ERR_INVALID_CID ):
            return "No channel with specified ID.";
        case  (0x0400+BLE_SM_ERR_PASSKEY ):
            return "The user input of passkey failed, for example, the user cancelled the operation.";
        case  (0x0400+BLE_SM_ERR_OOB ):
            return "The OOB data is not available.";
        case  (0x0400+BLE_SM_ERR_AUTHREQ ):
            return "The pairing procedure cannot be performed as authentication requirements cannot be met due to IO capabilities of one or both devices.";
        case  (0x0400+BLE_SM_ERR_CONFIRM_MISMATCH ):
            return "The confirm value does not match the calculated compare value.";
        case  (0x0400+BLE_SM_ERR_PAIR_NOT_SUPP ):
            return "Pairing is not supported by the device.";
        case  (0x0400+BLE_SM_ERR_ENC_KEY_SZ ):
            return "The resultant encryption key size is insufficient for the security requirements of this device.";
        case  (0x0400+BLE_SM_ERR_CMD_NOT_SUPP ):
            return "The SMP command received is not supported on this device.";
        case  (0x0400+BLE_SM_ERR_UNSPECIFIED ):
            return "Pairing failed due to an unspecified reason.";
        case  (0x0400+BLE_SM_ERR_REPEATED ):
            return "Pairing or authentication procedure disallowed, too little time has elapsed since last pairing request or security request.";
        case  (0x0400+BLE_SM_ERR_INVAL ):
            return "Command length is invalid or that a parameter is outside of the specified range.";
        case  (0x0400+BLE_SM_ERR_DHKEY ):
            return "DHKey Check value received doesn't match the one calculated by the local device.";
        case  (0x0400+BLE_SM_ERR_NUMCMP ):
            return "Confirm values in the numeric comparison protocol do not match.";
        case  (0x0400+BLE_SM_ERR_ALREADY ):
            return "Pairing over the LE transport failed - Pairing Request sent over the BR/EDR transport in process.";
        case  (0x0400+BLE_SM_ERR_CROSS_TRANS ):
            return "BR/EDR Link Key generated on the BR/EDR transport cannot be used to derive and distribute keys for the LE transport.";
        case  (0x0500+BLE_SM_ERR_PASSKEY ):
            return "The user input of passkey failed or the user cancelled the operation.";
        case  (0x0500+BLE_SM_ERR_OOB ):
            return "The OOB data is not available.";
        case  (0x0500+BLE_SM_ERR_AUTHREQ ):
            return "The pairing procedure cannot be performed as authentication requirements cannot be met due to IO capabilities of one or both devices.";
        case  (0x0500+BLE_SM_ERR_CONFIRM_MISMATCH ):
            return "The confirm value does not match the calculated compare value.";
        case  (0x0500+BLE_SM_ERR_PAIR_NOT_SUPP ):
            return "Pairing is not supported by the device.";
        case  (0x0500+BLE_SM_ERR_ENC_KEY_SZ ):
            return "The resultant encryption key size is insufficient for the security requirements of this device.";
        case  (0x0500+BLE_SM_ERR_CMD_NOT_SUPP ):
            return "The SMP command received is not supported on this device.";
        case  (0x0500+BLE_SM_ERR_UNSPECIFIED ):
            return "Pairing failed due to an unspecified reason.";
        case  (0x0500+BLE_SM_ERR_REPEATED ):
            return "Pairing or authentication procedure is disallowed because too little time has elapsed since last pairing request or security request.";
        case  (0x0500+BLE_SM_ERR_INVAL ):
            return "Command length is invalid or a parameter is outside of the specified range.";
        case  (0x0500+BLE_SM_ERR_DHKEY ):
            return "Indicates to the remote device that the DHKey Check value received doesn’t match the one calculated by the local device.";
        case  (0x0500+BLE_SM_ERR_NUMCMP ):
            return "Confirm values in the numeric comparison protocol do not match.";
        case  (0x0500+BLE_SM_ERR_ALREADY ):
            return "Pairing over the LE transport failed - Pairing Request sent over the BR/EDR transport in process.";
        case  (0x0500+BLE_SM_ERR_CROSS_TRANS ):
            return "BR/EDR Link Key generated on the BR/EDR transport cannot be used to derive and distribute keys for the LE transport.";
        default:
            return "Unknown";
    }
#else // #if defined(CONFIG_NIMBLE_CPP_ENABLE_RETURN_CODE_TEXT)
    return "";
#endif // #if defined(CONFIG_NIMBLE_CPP_ENABLE_RETURN_CODE_TEXT)
}


/**
 * @brief Convert the advertising type flag to a string.
 * @param advType The type to convert.
 * @return A string representation of the advertising flags.
 */
const char* NimBLEUtils::advTypeToString(uint8_t advType) {
#if defined(CONFIG_NIMBLE_CPP_ENABLE_ADVERTISMENT_TYPE_TEXT)
    switch(advType) {
        case BLE_HCI_ADV_TYPE_ADV_IND :                     //0
            return "Undirected - Connectable / Scannable";
        case BLE_HCI_ADV_TYPE_ADV_DIRECT_IND_HD:            //1
            return "Directed High Duty - Connectable";
        case BLE_HCI_ADV_TYPE_ADV_SCAN_IND:                 //2
            return "Non-Connectable - Scan Response Available";
        case BLE_HCI_ADV_TYPE_ADV_NONCONN_IND:              //3
            return "Non-Connectable - No Scan Response";
        case BLE_HCI_ADV_TYPE_ADV_DIRECT_IND_LD:            //4
            return "Directed Low Duty - Connectable";
        default:
            return "Unknown flag";
    }
#else // #if defined(CONFIG_NIMBLE_CPP_ENABLE_ADVERTISMENT_TYPE_TEXT)
    return "";
#endif // #if defined(CONFIG_NIMBLE_CPP_ENABLE_ADVERTISMENT_TYPE_TEXT)
} // adFlagsToString


/**
 * @brief Create a hex representation of data.
 *
 * @param [in] target Where to write the hex string. If this is null, we malloc storage.
 * @param [in] source The start of the binary data.
 * @param [in] length The length of the data to convert.
 * @return A pointer to the formatted buffer.
 */
char* NimBLEUtils::buildHexData(uint8_t* target, const uint8_t* source, uint8_t length) {
    // Guard against too much data.
    if (length > 100) length = 100;

    if (target == nullptr) {
        target = (uint8_t*) malloc(length * 2 + 1);
        if (target == nullptr) {
            NIMBLE_LOGE(LOG_TAG, "buildHexData: malloc failed");
            return nullptr;
        }
    }
    char* startOfData = (char*) target;

    for (int i = 0; i < length; i++) {
        sprintf((char*) target, "%.2x", (char) *source);
        source++;
        target += 2;
    }

    // Handle the special case where there was no data.
    if (length == 0) {
        *startOfData = 0;
    }

    return startOfData;
} // buildHexData


/**
 * @brief Utility function to log the gap event info.
 * @param [in] event A pointer to the gap event structure.
 * @param [in] arg Unused.
 */
void NimBLEUtils::dumpGapEvent(ble_gap_event *event, void *arg){
#if defined(CONFIG_NIMBLE_CPP_ENABLE_GAP_EVENT_CODE_TEXT)
    NIMBLE_LOGD(LOG_TAG, "Received a GAP event: %s", gapEventToString(event->type));
#endif
}


/**
 * @brief Convert a GAP event type to a string representation.
 * @param [in] eventType The type of event.
 * @return A string representation of the event type.
 */
const char* NimBLEUtils::gapEventToString(uint8_t eventType) {
#if defined(CONFIG_NIMBLE_CPP_ENABLE_GAP_EVENT_CODE_TEXT)
    switch (eventType) {
        case BLE_GAP_EVENT_CONNECT :                    //0
            return "BLE_GAP_EVENT_CONNECT ";

        case BLE_GAP_EVENT_DISCONNECT:                  //1
            return "BLE_GAP_EVENT_DISCONNECT";

        case BLE_GAP_EVENT_CONN_UPDATE:                 //3
            return "BLE_GAP_EVENT_CONN_UPDATE";

        case BLE_GAP_EVENT_CONN_UPDATE_REQ:             //4
            return "BLE_GAP_EVENT_CONN_UPDATE_REQ";

        case BLE_GAP_EVENT_L2CAP_UPDATE_REQ:            //5
            return "BLE_GAP_EVENT_L2CAP_UPDATE_REQ";

        case BLE_GAP_EVENT_TERM_FAILURE:                //6
            return "BLE_GAP_EVENT_TERM_FAILURE";

        case BLE_GAP_EVENT_DISC:                        //7
            return "BLE_GAP_EVENT_DISC";

        case BLE_GAP_EVENT_DISC_COMPLETE:               //8
            return "BLE_GAP_EVENT_DISC_COMPLETE";

        case BLE_GAP_EVENT_ADV_COMPLETE:                //9
            return "BLE_GAP_EVENT_ADV_COMPLETE";

        case BLE_GAP_EVENT_ENC_CHANGE:                  //10
            return "BLE_GAP_EVENT_ENC_CHANGE";

        case BLE_GAP_EVENT_PASSKEY_ACTION :             //11
            return "BLE_GAP_EVENT_PASSKEY_ACTION";

        case BLE_GAP_EVENT_NOTIFY_RX:                   //12
            return "BLE_GAP_EVENT_NOTIFY_RX";

        case BLE_GAP_EVENT_NOTIFY_TX :                  //13
            return "BLE_GAP_EVENT_NOTIFY_TX";

        case BLE_GAP_EVENT_SUBSCRIBE :                  //14
            return "BLE_GAP_EVENT_SUBSCRIBE";

        case BLE_GAP_EVENT_MTU:                         //15
            return "BLE_GAP_EVENT_MTU";

        case BLE_GAP_EVENT_IDENTITY_RESOLVED:           //16
            return "BLE_GAP_EVENT_IDENTITY_RESOLVED";

        case BLE_GAP_EVENT_REPEAT_PAIRING:              //17
            return "BLE_GAP_EVENT_REPEAT_PAIRING";

        case BLE_GAP_EVENT_PHY_UPDATE_COMPLETE:         //18
            return "BLE_GAP_EVENT_PHY_UPDATE_COMPLETE";

        case BLE_GAP_EVENT_EXT_DISC:                    //19
            return "BLE_GAP_EVENT_EXT_DISC";
#ifdef BLE_GAP_EVENT_PERIODIC_SYNC   // IDF 4.0 does not support these
        case BLE_GAP_EVENT_PERIODIC_SYNC:               //20
            return "BLE_GAP_EVENT_PERIODIC_SYNC";

        case BLE_GAP_EVENT_PERIODIC_REPORT:             //21
            return "BLE_GAP_EVENT_PERIODIC_REPORT";

        case BLE_GAP_EVENT_PERIODIC_SYNC_LOST:          //22
            return "BLE_GAP_EVENT_PERIODIC_SYNC_LOST";

        case BLE_GAP_EVENT_SCAN_REQ_RCVD:               //23
            return "BLE_GAP_EVENT_SCAN_REQ_RCVD";
#endif
        default:
            NIMBLE_LOGD(LOG_TAG, "gapEventToString: Unknown event type %d 0x%.2x", eventType, eventType);
            return "Unknown event type";
    }
#else // #if defined(CONFIG_NIMBLE_CPP_ENABLE_GAP_EVENT_CODE_TEXT)
    return "";
#endif // #if defined(CONFIG_NIMBLE_CPP_ENABLE_GAP_EVENT_CODE_TEXT)
} // gapEventToString

#endif //CONFIG_BT_ENABLED