Function BuildResponsePacket

engine/dlib/src/test/test_mdns.cpp:592–660

    }

    static void BuildResponsePacket(const RawDnsResponseRecord* records, uint32_t record_count, bool compress_names, std::vector<uint8_t>* buffer)
    {
        buffer->clear();
        WriteU16(buffer, 0);
        WriteU16(buffer, DNS_FLAG_RESPONSE);
        WriteU16(buffer, 0);
        WriteU16(buffer, (uint16_t) record_count);
        WriteU16(buffer, 0);
        WriteU16(buffer, 0);

        std::map<std::string, uint16_t> suffix_offsets;
        std::map<std::string, uint16_t>* offsets = compress_names ? &suffix_offsets : 0;

        for (uint32_t i = 0; i < record_count; ++i)
        {
            const RawDnsResponseRecord& record = records[i];
            WriteNameCompressed(buffer, record.m_Name, offsets);
            WriteU16(buffer, record.m_Type);
            WriteU16(buffer, record.m_Class);
            WriteU32(buffer, record.m_Ttl);

            const uint32_t rdlength_offset = (uint32_t) buffer->size();
            WriteU16(buffer, 0);
            const uint32_t rdata_start = (uint32_t) buffer->size();

            switch (record.m_Type)
            {
                case DNS_TYPE_PTR:
                {
                    WriteNameCompressed(buffer, record.m_PtrName, offsets);
                    break;
                }
                case DNS_TYPE_SRV:
                {
                    WriteU16(buffer, 0);
                    WriteU16(buffer, 0);
                    WriteU16(buffer, record.m_Port);
                    WriteNameCompressed(buffer, record.m_Target, offsets);
                    break;
                }
                case DNS_TYPE_TXT:
                {
                    for (uint32_t txt_i = 0; txt_i < record.m_TxtCount; ++txt_i)
                    {
                        char kv[320];
                        dmSnPrintf(kv, sizeof(kv), "%s=%s",
                                   record.m_Txt[txt_i].m_Key,
                                   record.m_Txt[txt_i].m_Value ? record.m_Txt[txt_i].m_Value : "");
                        const uint32_t len = (uint32_t) strlen(kv);
                        buffer->push_back((uint8_t) len);
                        buffer->insert(buffer->end(), kv, kv + len);
                    }

                    if (record.m_TxtCount == 0)
                    {
                        buffer->push_back(0);
                    }
                    break;