Function CompareProbeRecord

engine/dlib/src/dlib/mdns.cpp:869–880

Records sort by class, then type, then raw rdata bytes, matching the simultaneous-probe tiebreak order from RFC 6762 section 8.2.

    // Records sort by class, then type, then raw rdata bytes, matching the
    // simultaneous-probe tiebreak order from RFC 6762 section 8.2.
    static int CompareProbeRecord(const ProbeRecord& a, const ProbeRecord& b)
    {
        const uint16_t a_class = a.m_Class & ~DNS_CLASS_FLUSH;
        const uint16_t b_class = b.m_Class & ~DNS_CLASS_FLUSH;
        if (a_class != b_class)
            return a_class < b_class ? -1 : 1;

        if (a.m_Type != b.m_Type)
            return a.m_Type < b.m_Type ? -1 : 1;

        return CompareProbeData(a.m_RData, a.m_RDataLength, b.m_RData, b.m_RDataLength);
    }

    // Record sets must be sorted before pairwise tiebreak comparison so hosts
    // reach the same outcome even when authority records arrive in any order.