Method generateSocketID

srtcore/api.cpp:456–557

}

SRTSOCKET srt::CUDTUnited::generateSocketID(bool for_group)
{
    ScopedLock guard(m_IDLock);

    int sockval = m_SocketIDGenerator - 1;

    // First problem: zero-value should be avoided by various reasons.

    if (sockval <= 0)
    {
        // We have a rollover on the socket value, so
        // definitely we haven't made the Columbus mistake yet.
        m_SocketIDGenerator = MAX_SOCKET_VAL;
        sockval = MAX_SOCKET_VAL;
    }

    // Check all sockets if any of them has this value.
    // Socket IDs are begin created this way:
    //
    //                              Initial random
    //                              |
    //                             |
    //                            |
    //                           |
    // ...
    // The only problem might be if the number rolls over
    // and reaches the same value from the opposite side.
    // This is still a valid socket value, but this time
    // we have to check, which sockets have been used already.
    if (sockval == m_SocketIDGenerator_init)
    {
        // Mark that since this point on the checks for
        // whether the socket ID is in use must be done.
        m_SocketIDGenerator_init = 0;
    }

    // This is when all socket numbers have been already used once.
    // This may happen after many years of running an application
    // constantly when the connection breaks and gets restored often.
    if (m_SocketIDGenerator_init == 0)
    {
        int startval = sockval;
        for (;;) // Roll until an unused value is found
        {
            enterCS(m_GlobControlLock);
            const bool exists =
#if ENABLE_BONDING
                for_group
                ? m_Groups.count(sockval | SRTGROUP_MASK)
                :
#endif
                m_Sockets.count(sockval);
            leaveCS(m_GlobControlLock);

            if (exists)
            {
                // The socket value is in use.
                --sockval;