Parsing WHAD messages

When a firmware receives a WHAD message, it must determine its type and dispatch it accordingly.

Determining a message type

The whad_get_message_type() function must be called to discover the basic type of a received message. The return value is one of the whad_msgtype_t enum values:

WHAD_MSGTYPE_UNKNOWN: unknown message type, message must be discarded

WHAD_MSGTYPE_GENERIC: generic message, must be dispatched to generic messages handler

WHAD_MSGTYPE_DISCOVERY: discovery message, see WHAD Device discovery

WHAD_MSGTYPE_DOMAIN: domain-related message, must be dispatched to domain handler

Handling generic messages

Host-side message processing must determine the type of every incoming generic message using whad_generic_get_message_type(), following the template below. This function returns a value from the whad_generic_msgtype_t:

WHAD_GENERIC_UNKNOWN: unknown generic message, message must be discarded

WHAD_GENERIC_CMDRESULT: command result message

WHAD_GENERIC_VERBOSE: verbose message

WHAD_GENERIC_DEBUG: debug message

WHAD_GENERIC_PROGRESS: current progress by the firmware, value in range 0-100

void generic_handler(Message *p_message)
{
    whad_result_code_t result_code;

    switch (whad_generic_get_message_type(p_message))
    {
        case WHAD_GENERIC_CMDRESULT:
        {
            /* Process command result. */
            if (whad_generic_cmd_result_parse(p_message, &result_code) == WHAD_SUCCESS)
            {
                /* Process command result. */
            }
            else
            {
                /* Error while parsing command result. */
            }
        }
        break;

        case WHAD_GENERIC_VERBOSE:
        {
            /* No default parsing method available yet :/ */
        }
        break;

        case WHAD_GENERIC_DEBUG:
        {
            /* No default parsing method available yet :/ */
        }
        break;


        case WHAD_GENERIC_UNKNOWN:
        {
           /* Discard message. */
        }
        break;
    }
}

Handling domain messages

Domain messages must be dispatched to their respective domain message handler, using the whad_get_message_domain() function that returns a value of whad_domain_t enum. The following code template shows how such a dispatching process can be implemented:

void dispatch_domain_message(Message *p_message)
{
    Message response;

    switch (whad_get_message_domain(p_message))
    {
        /* Bluetooth Low Energy. */
        case DOMAIN_BTLE:
        {
            /* Forward message to BLE domain handler. */
            process_ble_message(p_message);
        }
        break;

        /* Bluetooth Low Energy. */
        case DOMAIN_DOT15D4:
        {
            /* Forward message to Dot15d4 domain handler. */
            process_dot15d4_message(p_message);
        }
        break;

        /* Bluetooth Low Energy. */
        case DOMAIN_ESB:
        {
            /* Forward message to ESB domain handler. */
            process_esb_message(p_message);
        }
        break;

        /* Bluetooth Low Energy. */
        case DOMAIN_PHY:
        {
            /* Forward message to PHY domain handler. */
            process_phy_message(p_message);
        }
        break;

        /* Bluetooth Low Energy. */
        case DOMAIN_UNIFYING:
        {
            /* Forward message to Unifying domain handler. */
            process_unifying_message(p_message);
        }
        break;

        /* Don't support other domains. */
        default:
        {
            /* Tell the host we don't support this domain. */
            whad_generic_cmd_result(&response, WHAD_RESULT_UNSUPPORTED_DOMAIN);
        }
        break;
    }
}

Important

If the hosts sends messages for an unsupported domain, the interface must answer with a whad_result_code_t::WHAD_RESULT_UNSUPPORTED_DOMAIN