Miscellaneous Fields¶

Conditional Fields¶

class pcapkit.corekit.fields.misc.SwitchField(selector=<function SwitchField.<lambda>>)[source]¶

Bases: FieldBase[_TC]

Conditional type-switching field for protocol schema.

Parameters:: selector (Callable[[dict[str, Any]], FieldBase[TypeVar(_TC)]]) – Callable function to select field type, which should accept the current packet as its only argument and return a field instance.

property name: str¶: Field name.

property default: _TC | NoValueType¶: Field default value.

property template: str¶: Field template.

property length: int¶: Field size.

property optional: bool¶: Field is optional.

property field: FieldBase[_TC]¶: Field instance.

__call__(packet)[source]¶

Call field.

Parameters:: packet (dict[str, Any]) – Packet data.
Return type:: SwitchField[TypeVar(_TC)]
Returns:: New field instance.

This method will return a new instance of SwitchField instead of updating the current instance.

pre_process(value, packet)[source]¶

Process field value before construction (packing).

Parameters:

value (TypeVar(_TC)) – Field value.
packet (dict[str, Any]) – Packet data.

Return type:

Any

Returns:

Processed field value.

pack(value, packet)[source]¶

Pack field value into bytes.

Parameters:

value (Optional[TypeVar(_TC)]) – Field value.
packet (dict[str, Any]) – Packet data.

Return type:

bytes

Returns:

Packed field value.

post_process(value, packet)[source]¶

Process field value after parsing (unpacking).

Parameters:

value (Any) – Field value.
packet (dict[str, Any]) – Packet data.

Return type:

TypeVar(_TC)

Returns:

Processed field value.

unpack(buffer, packet)[source]¶

Unpack field value from bytes.

Parameters:

buffer (Union[bytes, IO[bytes]]) – Field buffer.
packet (dict[str, Any]) – Packet data.

Return type:

TypeVar(_TC)

Returns:

Unpacked field value.

class pcapkit.corekit.fields.misc.ConditionalField(field, condition)[source]¶

Bases: FieldBase[_TC]

Conditional value for protocol fields.

Parameters:

field (FieldBase[TypeVar(_TC)]) – Field instance.
condition (Callable[[dict[str, Any]], bool]) – Field condition function (this function should return a bool value and accept the current packet pcapkit.corekit.infoclass.Info as its only argument).

property name: str¶: Field name.

property default: _TC | NoValueType¶: Field default value.

property template: str¶: Field template.

property length: int¶: Field size.

property optional: bool¶: Field is optional.

property field: FieldBase[_TC]¶: Field instance.

__call__(packet)[source]¶

Update field attributes.

Parameters:: packet (dict[str, Any]) – Packet data.
Return type:: Self
Returns:: Updated field instance.

This method will return a new instance of ConditionalField instead of updating the current instance.

pre_process(value, packet)[source]¶

Process field value before construction (packing).

Parameters:

value (TypeVar(_TC)) – Field value.
packet (dict[str, Any]) – Packet data.

Return type:

Any

Returns:

Processed field value.

pack(value, packet)[source]¶

Pack field value into bytes.

Parameters:

value (Optional[TypeVar(_TC)]) – Field value.
packet (dict[str, Any]) – Packet data.

Return type:

bytes

Returns:

Packed field value.

post_process(value, packet)[source]¶

Process field value after parsing (unpacking).

Parameters:

value (Any) – Field value.
packet (dict[str, Any]) – Packet data.

Return type:

TypeVar(_TC)

Returns:

Processed field value.

unpack(buffer, packet)[source]¶

Unpack field value from bytes.

Parameters:

buffer (Union[bytes, IO[bytes]]) – Field buffer.
packet (dict[str, Any]) – Packet data.

Return type:

TypeVar(_TC)

Returns:

Unpacked field value.

test(packet)[source]¶

Test field condition.

Parameters:: packet (dict[str, Any]) – Current packet.
Returns:: Test result.
Return type:: bool

class pcapkit.corekit.fields.misc.ForwardMatchField(field)[source]¶

Bases: FieldBase[_TC]

Schema field for non-capturing forward matching.

Parameters:: field (FieldBase[TypeVar(_TC)]) – Field to forward match.

property name: str¶: Field name.

property default: _TC | NoValueType¶: Field default value.

property template: str¶: Field template.

property length: int¶: Field size.

property optional: bool¶: Field is optional.

property field: FieldBase[_TC]¶: Field instance.

__call__(packet)[source]¶

Update field attributes.

Parameters:: packet (dict[str, Any]) – Packet data.
Return type:: Self
Returns:: Updated field instance.

This method will return a new instance of ConditionalField instead of updating the current instance.

pack(value, packet)[source]¶

Pack field value into bytes.

Parameters:

value (Optional[TypeVar(_TC)]) – Field value.
packet (dict[str, Any]) – Packet data.

Return type:

bytes

Returns:

Packed field value.

unpack(buffer, packet)[source]¶

Unpack field value from bytes.

Parameters:

buffer (Union[bytes, IO[bytes]]) – Field buffer.
packet (dict[str, Any]) – Packet data.

Return type:

TypeVar(_TC)

Returns:

Unpacked field value.

Generic Data Fields¶

class pcapkit.corekit.fields.misc.SchemaField(length=<function SchemaField.<lambda>>, schema=None, default=<pcapkit.corekit.fields.field.NoValueType object>, packet=None, callback=<function SchemaField.<lambda>>)[source]¶

Bases: FieldBase[_TS]

Schema field for protocol schema.

Parameters:

length (Union[int, Callable[[dict[str, Any]], int]]) – Field size (in bytes); if a callable is given, it should return an integer value and accept the current packet as its only argument.
schema (Optional[Type[TypeVar(_TS, bound= Schema)]]) – Field schema.
default (Union[TypeVar(_TS, bound= Schema), NoValueType, bytes]) – Default value for field.
packet (Optional[dict[str, Any]]) – Optional packet data for unpacking and/or packing purposes.
callback (Callable[[Self, dict[str, Any]], None]) – Callback function to process field value, which should accept the current field and the current packet as its arguments.

property length: int¶: Field size.

property optional: bool¶: Field is optional.

property schema: Type[_TS]¶: Field schema.

__call__(packet)[source]¶

Update field attributes.

Parameters:: packet (dict[str, Any]) – Packet data.
Return type:: Self
Returns:: New field instance.

This method will return a new instance of SchemaField instead of updating the current instance.

pack(value, packet)[source]¶

Pack field value into bytes.

Parameters:

value (Union[TypeVar(_TS, bound= Schema), bytes, None]) – Field value.
packet (dict[str, Any]) – Packet data.

Return type:

bytes

Returns:

Packed field value.

Notes

We will use packet as a __packet__ key in the packet context passed to the underlying Schema for packing purposes.

unpack(buffer, packet)[source]¶

Unpack field value from bytes.

Parameters:

buffer (Union[bytes, IO[bytes]]) – Field buffer.
packet (dict[str, Any]) – Packet data.

Return type:

TypeVar(_TS, bound= Schema)

Returns:

Unpacked field value.

Notes

We will use packet as a __packet__ key in the packet context passed to the underlying Schema for unpacking purposes.

class pcapkit.corekit.fields.misc.PayloadField(length=<function PayloadField.<lambda>>, default=<pcapkit.corekit.fields.field.NoValueType object>, protocol=None, callback=<function PayloadField.<lambda>>)[source]¶

Bases: FieldBase[_TP]

Payload value for protocol fields.

Parameters:

length (Union[int, Callable[[dict[str, Any]], int]]) – Field size (in bytes); if a callable is given, it should return an integer value and accept the current packet as its only argument.
default (Union[TypeVar(_TP, bound= Protocol), NoValueType, bytes]) – Field default value.
protocol (Optional[Type[TypeVar(_TP, bound= Protocol)]]) – Payload protocol.
callback (Callable[[Self, dict[str, Any]], None]) – Callback function to be called upon self.__call__.

property template: str¶: Field template.

property length: int¶: Field size.

property optional: bool¶: Field is optional.

property protocol: Type[_TP]¶: Payload protocol.

__call__(packet)[source]¶

Update field attributes.

Parameters:: packet (dict[str, Any]) – Packet data.
Return type:: Self
Returns:: Updated field instance.

This method will return a new instance of PayloadField instead of updating the current instance.

pack(value, packet)[source]¶

Pack field value into bytes.

Parameters:

value (Union[TypeVar(_TP, bound= Protocol), Schema, bytes, None]) – Field value.
packet (dict[str, Any]) – Packet data.

Return type:

bytes

Returns:

Packed field value.

unpack(buffer, packet)[source]¶

Unpack field value from bytes.

Parameters:

buffer (Union[bytes, IO[bytes]]) – Field buffer.
packet (dict[str, Any]) – Packet data.

Return type:

TypeVar(_TP, bound= Protocol)

Returns:

Unpacked field value.

class pcapkit.corekit.fields.misc.NoValueField(*args, **kwargs)[source]¶

Bases: FieldBase[_TN]

Schema field for no value type (or None).

property template: str¶: Field template.

property length: int¶: Field size.

pack(value, packet)[source]¶

Pack field value into bytes.

Parameters:

value (Optional[TypeVar(_TN, bound= NoValueType)]) – Field value.
packet (dict[str, Any]) – Packet data.

Return type:

bytes

Returns:

Packed field value.

unpack(buffer, packet)[source]¶

Unpack field value from bytes.

Parameters:

buffer (Union[bytes, IO[bytes]]) – Field buffer.
packet (dict[str, Any]) – Packet data.

Return type:

TypeVar(_TN, bound= NoValueType)

Returns:

Unpacked field value.

Type Variables¶

pcapkit.corekit.fields.misc._TC: Any¶

pcapkit.corekit.fields.misc._TS: pcapkit.protocols.schema.schema.Schema¶

pcapkit.corekit.fields.misc._TP: pcapkit.protocols.protocol.Protocol¶

pcapkit.corekit.fields.misc._TN: pcapkit.corekit.fields.field.NoValueType¶