secdev/scapy

Hello, I am using scapy with a new protocol, which defines one of its operations like this :

• each « config packet » is defined by a type, length and value
• the « set config » is defined by a count and a list of config packets

For now I defined it like this, which works well for most config packets:

APP_CONF_PARAMS = {
    # …
    0x06: {
        'name': 'DEVICE_MAC_ADDRESS',
        'field': XLEShortField("value", default=None)},
    0x07: {
        'name': 'DST_MAC_ADDRESS',
        'field': FieldListField('value', [], XLEShortField("item", default=None), length_from=lambda pkt: (pkt.length))}
    # …
}

APP_CONF_PARAM_NAME_BY_ID = {i: data['name'] for i, data in APP_CONF_PARAMS.items()}
APP_CONF_PARAM_FIELD_BY_ID = {i: data['field'] for i, data in APP_CONF_PARAMS.items()}

class AppConfigParameter(PacketWithNoPayload):
    fields_desc=[
        XByteEnumField("type", None, APP_CONF_PARAM_NAME_BY_ID),
        FieldLenField("length", None, fmt="B", length_of="value"),
        MultipleTypeField(
            # Use a field from APP_CONF_PARAMS if it can be found
            [(field, (lambda i: lambda pkt: pkt.type == i)(i)) for i,field in APP_CONF_PARAM_FIELD_BY_ID.items()],
            # Handle the parameter as a string if type is unknown
            XStrLenField("value", None, length_from=lambda pkt:pkt.length)
        )
    ]

class SessionSetAppConfigCmd(PacketWithNoPayload):

fields_desc=[
    FieldLenField("numberOfAppConfiguration", None, fmt='B', count_of="appConfiguration"),
    PacketListField("appConfiguration", [], AppConfigParameter,
        count_from=lambda pkt: pkt.numberOfAppConfiguration)
]