#393 Incorrect behaviour if MD timeout occurs

[Christoph Felser]

There are two problems related to this issue:

1. If receiving a MD reply in the same cycle as the timeout occurs, the stack informs the user (callback) a second time with TRDP_UNKNOWN_ERR.

2. If one o the MD requests has not been replied within configured timeout time (timeout event), the stack may inform the user (callback) with TRDP_UNKNOWN_ERR for other MD requests.

Approach

1. If receiving an MD reply, the stack shall not inform the user a second time.

2. Timeout event of MD request shall not have side effects on other MD requests.

Current implementation (trdp_mdCheckTimeouts in trdp_mdcom.c):

    do
    {
        TRDP_ERR_T resultCode = TRDP_UNKNOWN_ERR;

        /* Update the current time always inside loop in case of application delays  */
        vos_getTime(&now);

        /*  Switch to receive queue */
        if (NULL == iterMD && TRUE == firstLoop)
        {
            iterMD      = appHandle->pMDRcvQueue;
            firstLoop   = FALSE;
        }

        /*  Are we finished?   */
        if (NULL == iterMD)
        {
            break;
        }

        /* timeToGo is timeout value! */
        if (((iterMD->interval.tv_sec != TRDP_MD_INFINITE_TIME) ||
             (iterMD->interval.tv_usec != TRDP_MD_INFINITE_USEC_TIME)) &&
            (0 > vos_cmpTime(&iterMD->timeToGo, &now)))     /* timeout overflow */
        {
            timeOut = trdp_mdTimeOutStateHandler( iterMD, appHandle, &resultCode);
        }

        if (TRUE == timeOut)    /* Notify user  */
        {
            /* Execute callback */
            if (iterMD->pfCbFunction != NULL)
            {
                trdp_mdInvokeCallback(iterMD, appHandle, resultCode);
            }
        }

        iterMD = iterMD->pNext;
    }
    while (TRUE); /*lint !e506 */

Suggested fix (trdp_mdCheckTimeouts in trdp_mdcom.c):

    do
    {
        TRDP_ERR_T resultCode = TRDP_UNKNOWN_ERR;
        timeOut = FALSE; /* TRDP-104: Make shure that timeouts of MD request do not affect other MD requests */

        /* Update the current time always inside loop in case of application delays  */
        vos_getTime(&now);

        /*  Switch to receive queue */
        if (NULL == iterMD && TRUE == firstLoop)
        {
            iterMD      = appHandle->pMDRcvQueue;
            firstLoop   = FALSE;
        }

        /*  Are we finished?   */
        if (NULL == iterMD)
        {
            break;
        }

        /* FIX: Do not inform user if MD request is about to die */
        if (iterMD->morituri != TRUE)
        {
            /* timeToGo is timeout value! */
            if (((iterMD->interval.tv_sec != TRDP_MD_INFINITE_TIME) ||
                 (iterMD->interval.tv_usec != TRDP_MD_INFINITE_USEC_TIME)) &&
                (0 > vos_cmpTime(&iterMD->timeToGo, &now)))     /* timeout overflow */
            {
                timeOut = trdp_mdTimeOutStateHandler( iterMD, appHandle, &resultCode);
            }

            if (TRUE == timeOut)    /* Notify user  */
            {
                /* Execute callback */
                if (iterMD->pfCbFunction != NULL)
                {
                    trdp_mdInvokeCallback(iterMD, appHandle, resultCode);
                }
            }
        }
        iterMD = iterMD->pNext;
    }
    while (TRUE); /*lint !e506 */

[Chris Wetzler]

Fixed with revision: 2348