Class LenField

scapy/fields.py:2274–2294

If None, will be filled with the size of the payload

class LenField(Field[int, int]):
    """
    If None, will be filled with the size of the payload
    """
    __slots__ = ["adjust"]

    def __init__(self, name, default, fmt="H", adjust=lambda x: x):
        # type: (str, Optional[Any], str, Callable[[int], int]) -> None
        Field.__init__(self, name, default, fmt)
        self.adjust = adjust

    def i2m(self,
            pkt,  # type: Optional[Packet]
            x,  # type: Optional[int]
            ):
        # type: (...) -> int
        if x is None:
            x = 0
            if pkt is not None:
                x = self.adjust(len(pkt.payload))
        return x


class BCDFloatField(Field[float, int]):