Class NDRPacketField

scapy/layers/dcerpc.py:1942–1985

class NDRPacketField(NDRConstructedType, NDRAlign):
    def __init__(self, name, default, pkt_cls, **kwargs):
        self.DEPORTED_CONFORMANTS = pkt_cls.DEPORTED_CONFORMANTS
        self.fld = _NDRPacketField(name, default, pkt_cls=pkt_cls, **kwargs)
        NDRAlign.__init__(
            self,
            _NDRPacketPadField(self.fld, align=pkt_cls.ALIGNMENT),
            align=pkt_cls.ALIGNMENT,
        )
        NDRConstructedType.__init__(self, pkt_cls.fields_desc)

    def getfield(self, pkt, x):
        # Handle deformed conformants max_count here
        if self.DEPORTED_CONFORMANTS:
            # C706 14.3.2: "In other words, the size information precedes the
            # structure and is aligned independently of the structure alignment."
            fld = NDRInt3264Field("", 0)
            max_counts = []
            for _ in self.DEPORTED_CONFORMANTS:
                x, max_count = fld.getfield(pkt, x)
                max_counts.append(max_count)
            res, val = super(NDRPacketField, self).getfield(pkt, x)
            if len(max_counts) == 1:
                val.max_count = max_counts[0]
            else:
                val.max_counts = max_counts
            return res, val
        return super(NDRPacketField, self).getfield(pkt, x)

    def addfield(self, pkt, s, x):
        # Handle deformed conformants max_count here
        if self.DEPORTED_CONFORMANTS:
            mcfld = NDRInt3264Field("", 0)
            if len(self.DEPORTED_CONFORMANTS) == 1:
                max_counts = [x.max_count]
            else:
                max_counts = x.max_counts
            for fldname, max_count in zip(self.DEPORTED_CONFORMANTS, max_counts):
                if max_count is None:
                    fld, val = x.getfield_and_val(fldname)
                    max_count = fld.i2len(x, val)
                s = mcfld.addfield(pkt, s, max_count)
            return super(NDRPacketField, self).addfield(pkt, s, x)
        return super(NDRPacketField, self).addfield(pkt, s, x)


# Array types