Message EDNS Options — dnspython 2.8.0 documentation (original) (raw)

EDNS allows for larger messages and also provides an extension mechanism for the protocol. EDNS options are typed data, and are treated much like Rdata. For example, if dnspython encounters the EDNSECS option code when parsing a DNS wire format message, it will create a dns.edns.ECSOption object to represent it.

dns.edns.NSID = OptionType.NSID

dns.edns.DAU = OptionType.DAU

dns.edns.DHU = OptionType.DHU

dns.edns.N3U = OptionType.N3U

dns.edns.ECS = OptionType.ECS

dns.edns.EXPIRE = OptionType.EXPIRE

dns.edns.COOKIE = OptionType.COOKIE

dns.edns.KEEPALIVE = OptionType.KEEPALIVE

dns.edns.PADDING = OptionType.PADDING

dns.edns.CHAIN = OptionType.CHAIN

class dns.edns.Option(otype: OptionType | str)[source]

Base class for all EDNS option types.

Initialize an option.

otype, a dns.edns.OptionType, is the option type.

classmethod from_wire_parser(otype: OptionType, parser: Parser) → Option [source]

Build an EDNS option object from wire format.

otype, a dns.edns.OptionType, is the option type.

parser, a dns.wire.Parser, the parser, which should be restructed to the option length.

Returns a dns.edns.Option.

to_generic() → GenericOption [source]

Creates a dns.edns.GenericOption equivalent of this rdata.

Returns a dns.edns.GenericOption.

to_wire(file: Any | None = None) → bytes | None[source]

Convert an option to wire format.

Returns a bytes or None.

class dns.edns.GenericOption(otype: OptionType | str, data: bytes | str)[source]

Generic Option Class

This class is used for EDNS option types for which we have no better implementation.

Initialize an option.

otype, a dns.edns.OptionType, is the option type.

classmethod from_wire_parser(otype: OptionType | str, parser: Parser) → Option [source]

Build an EDNS option object from wire format.

otype, a dns.edns.OptionType, is the option type.

parser, a dns.wire.Parser, the parser, which should be restructed to the option length.

Returns a dns.edns.Option.

to_generic() → GenericOption [source]

Creates a dns.edns.GenericOption equivalent of this rdata.

Returns a dns.edns.GenericOption.

to_wire(file: Any | None = None) → bytes | None[source]

Convert an option to wire format.

Returns a bytes or None.

class dns.edns.ECSOption(address: str, srclen: int | None = None, scopelen: int = 0)[source]

EDNS Client Subnet (ECS, RFC7871)

address, a str, is the client address information.

srclen, an int, the source prefix length, which is the leftmost number of bits of the address to be used for the lookup. The default is 24 for IPv4 and 56 for IPv6.

scopelen, an int, the scope prefix length. This value must be 0 in queries, and should be set in responses.

static from_text(text: str) → Option [source]

Convert a string into a dns.edns.ECSOption

text, a str, the text form of the option.

Returns a dns.edns.ECSOption.

Examples:

import dns.edns

basic example
dns.edns.ECSOption.from_text('1.2.3.4/24')

also understands scope
dns.edns.ECSOption.from_text('1.2.3.4/24/32')

IPv6
dns.edns.ECSOption.from_text('2001:4b98::1/64/64')

it understands results from dns.edns.ECSOption.to_text()
dns.edns.ECSOption.from_text('ECS 1.2.3.4/24/32')

classmethod from_wire_parser(otype: OptionType | str, parser: Parser) → Option [source]

Build an EDNS option object from wire format.

otype, a dns.edns.OptionType, is the option type.

parser, a dns.wire.Parser, the parser, which should be restructed to the option length.

Returns a dns.edns.Option.

to_wire(file: Any | None = None) → bytes | None[source]

Convert an option to wire format.

Returns a bytes or None.

class dns.edns.EDEOption(code: EDECode | str, text: str | None = None)[source]

Extended DNS Error (EDE, RFC8914)

code, a dns.edns.EDECode or str, the info code of the extended error.

text, a str or None, specifying additional information about the error.

classmethod from_wire_parser(otype: OptionType | str, parser: Parser) → Option [source]

Build an EDNS option object from wire format.

otype, a dns.edns.OptionType, is the option type.

parser, a dns.wire.Parser, the parser, which should be restructed to the option length.

Returns a dns.edns.Option.

to_wire(file: Any | None = None) → bytes | None[source]

Convert an option to wire format.

Returns a bytes or None.

class dns.edns.NSIDOption(nsid: bytes)[source]

Initialize an option.

otype, a dns.edns.OptionType, is the option type.

classmethod from_wire_parser(otype: OptionType | str, parser: Parser) → Option [source]

Build an EDNS option object from wire format.

otype, a dns.edns.OptionType, is the option type.

parser, a dns.wire.Parser, the parser, which should be restructed to the option length.

Returns a dns.edns.Option.

to_wire(file: Any = None) → bytes | None[source]

Convert an option to wire format.

Returns a bytes or None.

class dns.edns.CookieOption(client: bytes, server: bytes)[source]

Initialize an option.

otype, a dns.edns.OptionType, is the option type.

classmethod from_wire_parser(otype: OptionType | str, parser: Parser) → Option [source]

Build an EDNS option object from wire format.

otype, a dns.edns.OptionType, is the option type.

parser, a dns.wire.Parser, the parser, which should be restructed to the option length.

Returns a dns.edns.Option.

to_wire(file: Any = None) → bytes | None[source]

Convert an option to wire format.

Returns a bytes or None.

class dns.edns.ReportChannelOption(agent_domain: Name)[source]

Initialize an option.

otype, a dns.edns.OptionType, is the option type.

classmethod from_wire_parser(otype: OptionType | str, parser: Parser) → Option [source]

Build an EDNS option object from wire format.

otype, a dns.edns.OptionType, is the option type.

parser, a dns.wire.Parser, the parser, which should be restructed to the option length.

Returns a dns.edns.Option.

to_wire(file: Any = None) → bytes | None[source]

Convert an option to wire format.

Returns a bytes or None.

dns.edns.get_option_class(otype: OptionType) → Any[source]

Return the class for the specified option type.

The GenericOption class is used if a more specific class is not known.

dns.edns.option_from_wire_parser(otype: OptionType | str, parser: Parser) → Option [source]

Build an EDNS option object from wire format.

otype, an int, is the option type.

parser, a dns.wire.Parser, the parser, which should be restricted to the option length.

Returns an instance of a subclass of dns.edns.Option.

dns.edns.option_from_wire(otype: OptionType | str, wire: bytes, current: int, olen: int) → Option [source]

Build an EDNS option object from wire format.

otype, an int, is the option type.

wire, a bytes, is the wire-format message.

current, an int, is the offset in wire of the beginning of the rdata.

olen, an int, is the length of the wire-format option data

Returns an instance of a subclass of dns.edns.Option.

dns.edns.register_type(implementation: Any, otype: OptionType) → None[source]

implementation, a class, is a subclass of dns.edns.Option.

otype, an int, is the option type.

Message EDNS Options — dnspython 2.8.0 documentation (original) (raw)

basic example

also understands scope

IPv6

it understands results from dns.edns.ECSOption.to_text()

it understands results from `dns.edns.ECSOption.to_text()`