[BUG] Reject if the Extension Flags field does not contain the magic value (INDUCTION PHASE)

[maxsharabayko]

According to the SRT Internet-Draft, if the Extension Flags field does not contain the magic value 0x4A17 the connection is rejected. This is a contingency for the case where someone who, in an attempt to extend UDT independently, increases the Version value to 5 and tries to test it against SRT.

Looking at the code, it does not seem to happen so:

EConnectStatus srt::CUDT::processConnectResponse(...)
        // ..
        if (m_ConnRes.m_iReqType == URQ_INDUCTION)
        {
            // ...
            if (m_ConnRes.m_iVersion > HS_VERSION_UDT4)
            {
                int hs_flags = SrtHSRequest::SRT_HSTYPE_HSFLAGS::unwrap(m_ConnRes.m_iType);

                if (hs_flags != SrtHSRequest::SRT_MAGIC_CODE)
                {
                    LOGC(cnlog.Warn,
                         log << CONID() << "processConnectResponse: Listener HSv5 did not set the SRT_MAGIC_CODE");
                }

As can be seen from the code, only a warning will be shown.

TODO:

• Reproduce the behavior.
• The rejection reason must be SRT_REJ_ROGUE.