Class DataPacket

scapy/contrib/rtps/rtps.py:165–208

class DataPacket(EPacket):
    name = "Data Packet"
    _pl_type = None
    _pl_len = 0

    fields_desc = [
        XShortField("encapsulationKind", 0),
        XShortField("encapsulationOptions", 0),
        # if payload encoding == PL_CDR_{LE,BE} then parameter list
        ConditionalField(
            EPacketField("parameterList", "", ParameterListPacket),
            lambda pkt: pkt.encapsulationKind == 0x0003,
        ),
        # if writer entity id == 0x200c2: then participant message data
        ConditionalField(
            EPacketField(
                "participantMessageData", "", ParticipantMessageDataPacket),
            lambda pkt: pkt._pl_type == "ParticipantMessageData",
        ),
        # else (neither the cases)
        ConditionalField(
            SerializedDataField(
                "serializedData", "", length_from=lambda pkt: pkt._pl_len
            ),
            lambda pkt: (
                pkt.encapsulationKind != 0x0003 \
                and pkt._pl_type != "ParticipantMessageData"
            ),
        ),
    ]

    def __init__(self, *args, **kwargs):
        writer_entity_id_key = kwargs.pop("writer_entity_id_key", None)
        writer_entity_id_kind = kwargs.pop("writer_entity_id_kind", None)
        pl_len = kwargs.pop("pl_len", 0)
        if (writer_entity_id_key == 0x200 or writer_entity_id_key == 0x100) and \
                writer_entity_id_kind == 0xC2:
            DataPacket._pl_type = "ParticipantMessageData"
        else:
            DataPacket._pl_type = "SerializedData"

        DataPacket._pl_len = pl_len

        super(DataPacket, self).__init__(*args, **kwargs)


class RTPSSubMessage_DATA(EPacket):