Method checkACKTimer

srtcore/core.cpp:11912–11949

}

int srt::CUDT::checkACKTimer(const steady_clock::time_point &currtime)
{
    int because_decision = BECAUSE_NO_REASON;
    if (currtime > m_tsNextACKTime.load()  // ACK time has come
                                  // OR the number of sent packets since last ACK has reached
                                  // the congctl-defined value of ACK Interval
                                  // (note that none of the builtin congctls defines ACK Interval)
        || (m_CongCtl->ACKMaxPackets() > 0 && m_iPktCount >= m_CongCtl->ACKMaxPackets()))
    {
        // ACK timer expired or ACK interval is reached
        sendCtrl(UMSG_ACK);

        const steady_clock::duration ack_interval = m_CongCtl->ACKTimeout_us() > 0
            ? microseconds_from(m_CongCtl->ACKTimeout_us())
            : m_tdACKInterval;
        m_tsNextACKTime.store(currtime + ack_interval);

        m_iPktCount      = 0;
        m_iLightACKCount = 1;
        because_decision = BECAUSE_ACK;
    }

    // Or the transfer rate is so high that the number of packets
    // have reached the value of SelfClockInterval * LightACKCount before
    // the time has come according to m_tsNextACKTime. In this case a "lite ACK"
    // is sent, which doesn't contain statistical data and nothing more
    // than just the ACK number. The "fat ACK" packets will be still sent
    // normally according to the timely rules.
    else if (m_iPktCount >= SELF_CLOCK_INTERVAL * m_iLightACKCount)
    {
        // send a "light" ACK
        sendCtrl(UMSG_ACK, NULL, NULL, SEND_LITE_ACK);
        ++m_iLightACKCount;
        because_decision = BECAUSE_LITEACK;
    }

    return because_decision;
}

int srt::CUDT::checkNAKTimer(const steady_clock::time_point& currtime)
{