IPv6-Route - Routing Header for IPv6

pcapkit.protocols.internet.ipv6_route contains IPv6_Route only, which implements extractor for Routing Header for IPv6 (IPv6-Route) [*], whose structure is described as below:

Octets	Bits	Name	Description
0	0	route.next	Next Header
1	8	route.length	Header Extension Length
2	16	route.type	Routing Type
3	24	route.seg_left	Segments Left
4	32	route.data	Type-Specific Data

class pcapkit.protocols.internet.ipv6_route.IPv6_Route(file=None, length=None, **kwargs)

Bases: IPv6_Ext[IPv6_Route, IPv6_Route]

This class implements Routing Header for IPv6.

This class parses the following Routing Header for IPv6 routing data types, which are registered in the self.__routing__ attribute:

Routing Code	Data Parser	Data Constructor
Source_Route	_read_data_type_src()	_make_data_type_src()
Type_2_Routing_Header	_read_data_type_2()	_make_data_type_2()
RPL_Source_Route_Header	_read_data_type_rpl()	_make_data_type_rpl()

Changed in version 1.3.4: length, and the length field of the parsed data model, is the header’s size in octets rather than the raw Hdr Ext Len value (#218).

Changed in version 1.5.0:

• Hdr Ext Len is in 8-octet units both on read and on build (#487).

• The RPL fixed area is sized at 4 octets, per RFC 6554 (#564).

• A bool given as an address raises FieldValueError (#540).

• make() takes data as bytes for every routing type (#1236), and an RPL source route rebuilds byte for byte, its address compression and a truncated address list included (#1456, #1457).

• A rebuild keeps the reserved bits of an RPL source route (#1235), and the reserved octets of a Source Route or Type 2 header and the Pad octets of an RPL one as captured (#1223).

property name: Literal['Routing Header for IPv6']

Name of current protocol.

property alias: Literal['IPv6-Route']

Acronym of corresponding protocol.

property length: int

Header length of current protocol.

property payload: ProtocolBase | NoReturn

Payload of current instance.

Raises:

UnsupportedCall – if the protocol is used as an IPv6 extension header

Return type:

pcapkit.protocols.protocol.Protocol

property protocol: str | None | NoReturn

Name of next layer protocol (if any).

Raises:

UnsupportedCall – if the protocol is used as an IPv6 extension header

property protochain: ProtoChain | NoReturn

Protocol chain of current instance.

Raises:

UnsupportedCall – if the protocol is used as an IPv6 extension header

classmethod register_routing(code, meth)

Register a routing data parser.

Parameters:

• code (Routing) – IPv6-Route data type code.

• meth (str | tuple[Callable[[RoutingType, IPv6_Route], IPv6_Route], Callable[[Routing, IPv6_Route | None, IPv6Address | None, Any], RoutingType]]) – Method name or callable to parse and/or construct the data.

Warns:

RegistryWarning – If a different entry is already registered for code; it is overwritten. Handing back the entry already stored, or one equal to it, is a silent no-op. The entry code shipped with is accepted like any other, so an override can be undone (#1362, #1363).

read(length=None, *, extension=False, **kwargs)

Read Routing Header for IPv6.

Structure of IPv6-Route header [RFC 8200][RFC 5095]:

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Next Header  |  Hdr Ext Len  |  Routing Type | Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
.                                                               .
.                       type-specific data                      .
.                                                               .
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Parameters:

• length (int | None) – Length of packet data.

• extension (bool) – If the packet is used as an IPv6 extension header.

• **kwargs (Any) – Arbitrary keyword arguments.

Return type:

IPv6_Route

Returns:

Parsed packet data.

make(dst=None, next=<TransType.UDP: 17>, next_default=None, next_namespace=None, next_reversed=False, type=<Routing.Source_Route: 0>, type_default=None, type_namespace=None, type_reversed=False, seg_left=0, data=b'\\x00\\x00\\x00\\x00', hdr_ext_len=None, payload=b'', **kwargs)

Make (construct) packet data.

Parameters:

• dst (IPv6Address | str | int | bytes | None) – Destination address.

• next (TransType | IntEnum | IntEnum | str | int) – Next header type.

• next_default (int | None) – Default value of next header type.

• next_namespace (dict[str, int] | dict[int, str] | Type[IntEnum] | Type[IntEnum] | None) – Namespace of next header type.

• next_reversed (bool) – If the namespace of next header type is reversed.

• type (Routing | IntEnum | IntEnum | str | int) – Routing type.

• type_default (int | None) – Default value of routing type.

• type_namespace (dict[str, int] | dict[int, str] | Type[IntEnum] | Type[IntEnum] | None) – Namespace of routing type.

• type_reversed (bool) – If the namespace of routing type is reversed.

• seg_left (int) – Segments left.

• data (bytes | IPv6_Route | RoutingType | dict[str, Any]) – Routing data.

• hdr_ext_len (int | None) – Hdr Ext Len field value; computed from data when omitted.

• payload (ProtocolBase | Schema | bytes) – Payload of current instance.

• **kwargs (Any) – Arbitrary keyword arguments.

Return type:

IPv6_Route

Returns:

Constructed packet data.

Raises:

FieldValueError – If dst is a bool (c.f. parse_ip_address()).

classmethod _make_data(data)

Create key-value pairs from data for protocol construction.

Parameters:

data (IPv6_Route) – protocol data

Return type:

dict[str, Any]

Returns:

Key-value pairs for protocol construction.

static _make_hdr_ext_len(data_length)

Compute Hdr Ext Len for a type-specific data payload of data_length octets.

Per RFC 8200 Section 4.4, Hdr Ext Len is the length of the Routing header in 8-octet units, not including the first 8 octets. The fixed part (next/length/type/seg_left) is 4 octets, so the on-the-wire header is 4 + data_length octets; equating that to 8 + 8 * hdr_ext_len gives hdr_ext_len = (data_length - 4) / 8. ipv6_route_data_length in pcapkit.protocols.schema.internet.ipv6_route is the inverse, used on the read side.

This is the only place Hdr Ext Len is computed on the write side: separate per-branch copies in make() drift apart, so keep one helper. Do NOT “simplify” the - 4 / / 8 away: the units either side differ (octets vs. 8-octet units), and dropping the offset silently reinterprets the field.

Parameters:

data_length (int) – packed length, in octets, of the type-specific data (i.e. len(data_val.pack()) for a Schema-based payload, or the padded raw bytes length for the unknown/raw-bytes case).

Return type:

int

Returns:

The Hdr Ext Len field value.

_read_data_type_none(schema, *, header)

Read IPv6-Route unknown type data.

Structure of IPv6-Route unknown type data [RFC 8200][RFC 5095]:

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Next Header  |  Hdr Ext Len  |  Routing Type | Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
.                                                               .
.                       type-specific data                      .
.                                                               .
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Parameters:

• schema (UnknownType) – parsed routing data schema

• header (IPv6_Route) – parsed IPv6-Route header schema

Return type:

UnknownType

Returns:

Parsed route data.

_read_data_type_src(schema, *, header)

Read IPv6-Route Source Route data.

Structure of IPv6-Route Source Route data [RFC 5095]:

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Next Header  |  Hdr Ext Len  | Routing Type=0| Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                            Reserved                           |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
+                                                               +
|                                                               |
+                           Address[1]                          +
|                                                               |
+                                                               +
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
+                                                               +
|                                                               |
+                           Address[2]                          +
|                                                               |
+                                                               +
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
.                               .                               .
.                               .                               .
.                               .                               .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
+                                                               +
|                                                               |
+                           Address[n]                          +
|                                                               |
+                                                               +
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Parameters:

• schema (SourceRoute) – parsed routing data schema

• header (IPv6_Route) – parsed IPv6-Route header schema

Return type:

SourceRoute

Returns:

Parsed route data.

_read_data_type_2(schema, *, header)

Read IPv6-Route Type 2 data.

Structure of IPv6-Route Type 2 data [RFC 6275]:

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Next Header  | Hdr Ext Len=2 | Routing Type=2|Segments Left=1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                            Reserved                           |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
+                                                               +
|                                                               |
+                         Home Address                          +
|                                                               |
+                                                               +
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Parameters:

• schema (Type2) – parsed routing data schema

• header (IPv6_Route) – parsed IPv6-Route header schema

Return type:

Type2

Returns:

Parsed route data.

Raises:

ProtocolError – If Hdr Ext Len is NOT 2.

_read_data_type_rpl(schema, *, header)

Read IPv6-Route RPL Source data.

Structure of IPv6-Route RPL Source data [RFC 6554]:

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Next Header  |  Hdr Ext Len  | Routing Type  | Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CmprI | CmprE |  Pad  |               Reserved                |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
.                                                               .
.                        Addresses[1..n]                        .
.                                                               .
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Parameters:

• schema (RPL) – parsed routing data schema

• header (IPv6_Route) – parsed IPv6-Route header schema

Return type:

RPL

Returns:

Parsed route data.

_make_data_type_none(type, route=None, *, dst=None, data=b'\\x00\\x00\\x00\\x00', **kwargs)

Make IPv6-Route unknown type data.

Parameters:

• type (Routing) – routing type

• route (UnknownType | None) – route data

• dst (IPv6Address | None) – destination IPv6 address

• data (bytes) – raw route data as bytes

• **kwargs (Any) – arbitrary keyword arguments

Return type:

UnknownType

Returns:

Constructed route data schema.

_make_data_type_src(type, route=None, *, dst=None, ip=None, reserved=b'\\x00\\x00\\x00\\x00', **kwargs)

Make IPv6-Route Source Route data.

Parameters:

• type (Routing) – routing type

• route (SourceRoute | None) – route data

• dst (IPv6Address | None) – destination IPv6 address

• ip (list[bytes | str | int | IPv6Address] | None) – list of IPv6 addresses

• reserved (bytes) – the four reserved octets, truncated or zero-filled to four octets

• **kwargs (Any) – arbitrary keyword arguments

Return type:

SourceRoute

Returns:

Constructed route data schema.

_make_data_type_2(type, route=None, *, dst=None, ip='::', reserved=b'\\x00\\x00\\x00\\x00', **kwargs)

Make IPv6-Route Type 2 data.

Parameters:

• type (Routing) – routing type

• route (Type2 | None) – route data

• dst (IPv6Address | None) – destination IPv6 address

• ip (IPv6Address | str | bytes | int) – home address

• reserved (bytes) – the four reserved octets, truncated or zero-filled to four octets

• **kwargs (Any) – arbitrary keyword arguments

Return type:

Type2

Returns:

Constructed route data schema.

_make_data_type_rpl(type, route=None, *, dst=None, ip=None, reserved=0, padding=b'', **kwargs)

Make IPv6-Route RPL Source data.

Parameters:

• type (Routing) – routing type

• route (RPL | None) – route data

• dst (IPv6Address | None) – destination IPv6 address

• ip (list[bytes | str | int | IPv6Address] | None) – list of IPv6 addresses

• reserved (int) – reserved bits after Pad

• padding (bytes) – the Pad octets after the addresses, truncated or zero-filled to Pad octets

• **kwargs (Any) – arbitrary keyword arguments

Return type:

RPL

Returns:

Constructed route data schema.

Raises:

• FieldValueError – If an entry of ip is a bool (c.f. parse_ip_address()).

• ProtocolError – If ip is empty.

__routing__: DefaultDict[Routing | int, str | tuple[Callable[[RoutingType, IPv6_Route], IPv6_Route], Callable[[Routing, IPv6_Route | None, IPv6Address | None, Any], RoutingType]]]

Type code to method mapping. A str value names the methods _read_data_type_${name} and _make_data_type_${name}, falling back to _read_data_type_none / _make_data_type_none when they do not exist; any other value is a (parser, constructor) pair of callables.

Type:

DefaultDict[Enum_Routing, str | tuple[TypeParser, TypeConstructor]]

__post_init__(file=None, length=None, *, extension=False, **kwargs)

Post initialisation hook.

Overloads:

• self, file (IO[bytes] | bytes), length (Optional[int]), extension (bool), src_ip (Optional[IPv6Address]), dst_ip (Optional[IPv6Address]), kwargs (Any) → None

• self, kwargs (Any) → None

Parameters:

• file (IO[bytes] | bytes | None) – Source packet stream.

• length (int | None) – Length of packet data.

• extension (bool) – If the protocol is used as an IPv6 extension header.

• src_ip – source IP address

• dst_ip – destination IP address

• **kwargs (Any) – Arbitrary keyword arguments.

Note

src_ip and dst_ip are declared only in the @overload stub above, which types them as optional keyword parameters. The runtime accepts them through **kwargs without defaulting them. The discrepancy with the implementation signature is deliberate (GitHub issue #505).

See also

For construction argument, please refer to self.make.

classmethod __index__()

Numeral registry index of the protocol.

Return type:

TransType

Returns:

Numeral registry index of the protocol in IANA.

Header Schemas

class pcapkit.protocols.schema.internet.ipv6_route.IPv6_Route(*args: _VT, **kwargs: _VT)

Bases: Schema

Header schema for IPv6-Route packet.

next: TransType = <EnumField next>

Next header.

length: int = <UInt8Field length>

Header extension length.

type: Routing = <EnumField type>

Routing type.

seg_left: int = <UInt8Field seg_left>

Segments left.

data: RoutingType = <SwitchField data>

Routing data.

payload: bytes = <PayloadField payload>

Payload.

class pcapkit.protocols.schema.internet.ipv6_route.RoutingType(dict_=None, **kwargs)

Bases: EnumSchema[Routing]

Header schema for IPv6-Route type-specific routing data.

class pcapkit.protocols.schema.internet.ipv6_route.UnknownType(*args: _VT, **kwargs: _VT)

Bases: RoutingType

Header schema for IPv6-Route unknown type routing data.

data: bytes = <BytesField data>

Type-specific data.

class pcapkit.protocols.schema.internet.ipv6_route.SourceRoute(*args: _VT, **kwargs: _VT)

Bases: RoutingType

Header schema for IPv6-Route source route routing data.

reserved: bytes = <PaddingField reserved>

Reserved.

ip: list[IPv6Address] = <ListField ip>

Addresses.

class pcapkit.protocols.schema.internet.ipv6_route.Type2(*args: _VT, **kwargs: _VT)

Bases: RoutingType

Header schema for IPv6-Route type 2 routing data.

reserved: bytes = <PaddingField reserved>

Reserved.

ip: IPv6Address = <IPv6AddressField ip>

Home address.

class pcapkit.protocols.schema.internet.ipv6_route.RPL(*args: _VT, **kwargs: _VT)

Bases: RoutingType

Header schema for IPv6-Route RPL routing data.

Removed in version 1.5.0: cmpr_i and cmpr_e, now the keys of cmpr (#1456).

cmpr: CmprInfo = <BitField cmpr>

CmprI and CmprE – two 4-bit counts sharing one octet.

NOTE: RFC 6554 Section 3 gives CmprI and CmprE as “4-bit unsigned integer”, i.e. the high and low nibble of a single octet, so they cannot be two UInt8Field (one octet each). Together with pad below – Pad (4 bits) plus Reserved (20 bits) – this is the one 32-bit word the diagram in RFC 6554 Section 3 draws, and the same word IPv6_Route._read_data_type_rpl’s own docstring draws. The split between the two fields falls on the octet boundary between CmprE and Pad, so neither straddles an octet.

pad: PadInfo = <BitField pad>

Padding length and reserved.

addresses: bytes = <ListField addresses>

Addresses.

padding: bytes = <PaddingField padding>

Padding.

classmethod pre_unpack(packet)

Prepare packet data for unpacking process.

Parameters:

packet (dict[str, Any]) – packet data

post_process(packet)

Revise schema data after unpacking process.

Parameters:

packet (dict[str, Any]) – Unpacked data.

Return type:

Schema

Returns:

Revised schema.

ip: list[IPv6Address | bytes]

Addresses (SRH prefix compression decoded).

Type Stubs

class pcapkit.protocols.schema.internet.ipv6_route.CmprInfo

Bases: TypedDict

Prefix-compression counts, two nibbles of a single octet.

class pcapkit.protocols.schema.internet.ipv6_route.PadInfo

Bases: TypedDict

Padding length and reserved.

Auxiliary Functions

pcapkit.protocols.schema.internet.ipv6_route.ipv6_route_data_selector(pkt)

Selector function for IPv6_Route.data field.

Parameters:

pkt (dict[str, Any]) – Packet data.

Return type:

FieldBase

Returns:

A SchemaField wrapped RoutingType instance based on IPv6_Route.type.

pcapkit.protocols.schema.internet.ipv6_route.ipv6_route_data_length(hdr_ext_len)

Length, in octets, of the IPv6-Route type-specific data for a given Hdr Ext Len.

Per RFC 8200 Section 4.4, Hdr Ext Len is “the length of the Routing header in 8-octet units, not including the first 8 octets” – i.e. the total on-the-wire header is 8 + 8 * hdr_ext_len octets. Of that, the 4 octets of next/length/type/seg_left are not part of the type-specific data, so the data itself – what ipv6_route_data_selector() hands to the nested RoutingType schema – is 4 + 8 * hdr_ext_len octets. This is the single place that arithmetic is done on the read side; see _make_hdr_ext_len() for its inverse on the write side. Dropping the 4 + would leave the data length 4 octets short.

Parameters:

hdr_ext_len (int) – raw Hdr Ext Len field value, as read off the wire.

Return type:

int

Returns:

Length, in octets, of the type-specific data.

Data Models

class pcapkit.protocols.data.internet.ipv6_route.IPv6_Route(dict_=None, **kwargs)

Bases: Protocol

Data model for IPv6-Route protocol.

next: TransType

Next header.

length: int

Header length, in octets, decoded from Hdr Ext Len.

type: Routing

Routing type.

seg_left: int

Segments left.

class pcapkit.protocols.data.internet.ipv6_route.UnknownType(*args: VT, **kwargs: VT)

Bases: IPv6_Route

Data model for IPv6-Route unknown type.

data: bytes

Data.

class pcapkit.protocols.data.internet.ipv6_route.SourceRoute(*args: VT, **kwargs: VT)

Bases: IPv6_Route

Data model for IPv6-Route Source Route data type.

Changed in version 1.5.0: New required field reserved (#1223).

reserved: bytes

The four reserved octets, as captured.

ip: tuple[IPv6Address, ...]

Source addresses.

class pcapkit.protocols.data.internet.ipv6_route.Type2(*args: VT, **kwargs: VT)

Bases: IPv6_Route

Data model for IPv6-Route Type 2 data type.

Changed in version 1.5.0: New required field reserved (#1223).

reserved: bytes

The four reserved octets, as captured.

ip: IPv6Address

Address.

class pcapkit.protocols.data.internet.ipv6_route.RPL(*args: VT, **kwargs: VT)

Bases: IPv6_Route

Data model for RPL Source data type.

Changed in version 1.5.0: New required fields reserved (#1235) and padding (#1223).

cmpr_i: int

CmprI.

cmpr_e: int

CmprE.

pad: int

Pad.

reserved: int

Reserved bits, carried verbatim so that a rebuild reproduces them.

ip: tuple[IPv6Address | bytes, ...]

Addresses.

padding: bytes

The Pad octets after the addresses, as captured.

Footnotes

[*]

https://en.wikipedia.org/wiki/IPv6_packet#Routing