NGAP Protocol

[priyanshs]

Hello, Is it possible to add NGAP protocol support to the kit? It is mainly used in 5G Networks. How would one go about adding support for it?
TIA

[JarryShaw]

Yes, it would be pretty much welcomed if you could add the protocol support yourself.

To do this, I would suppose this is an application layer protocol, you need to create a skeleton class that represents the protocol itself, a data class that holds the protocol header fields, and a schema class that defines the structure of the protocol.

Schema Class

from pcapkit.corekit.fields.numbers import UInt32Field
from pcapkit.corekit.fields.strings import BytesField
from pcapkit.protocols.schema.schema import Schema, schema_final


@schema_final  # this will automatically generate a constructor for this class
class Schema_NGAP(Schema):
	# now you define the fields in order, for example, we say it has firstly two ports then binary data
	port_one = UInt32Field()
	port_two = UInt32Field()
	data = BytesField(lambda: pkt: pkt['__length__'])

for more information on the pkt lambda used in the field definitions, please see the Schema class's documentation

Data Class

from pcapkit.corekit.infoclass import info_final
from pcapkit.protocols.data.protocol import Protocol


@info_final
class Data_NGAP(Protocol):
	port_one: int
	port_two: int
	data: bytes

Skeleton Class

from pcapkit.protocols.application.application import Application
from pcapkit.utilities.exceptions import ProtocolError, UnsupportedCall


class NGAP(Application[Data_GNAP, Schema_NGAP], data=Data_NGAP, schema=Schema_NGAP):

	@property
	def name(self):
		return 'NG Application Protocol'

	def read(self, length: 'Optional[int]' = None, **kwargs: 'Any') -> 'Data_NGAP':
		if length is None:
			length = len(self)
		schema = self.__header__

		# extra handling of data mapping/processing can be done here before storing to the data class
		return Data_NGAP(port_one=schema.port_one, port_two=schema.port_two, data=schema.data)

	def make(...) -> Schema_NGAP':  # constructor for the protocol with given args
 		...
		return Schema_NGAP(port_one=..., port_two=..., data=...)

Protocol Registration

If this protocol is wrapped under TCP (or UDP is the same), then you can register it by calling the register method:

from pcapkit.protocols.transport.tcp import TCP

TCP.register(port_number, NGAP)