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//! DNS EDNS0 pption codes.
//------------ OptionCode ----------------------------------------------------
int_enum! {
/// DNS EDNS0 option codes.
///
/// The record data of [OPT] records is a sequence of options. The type of
/// each of these options is given through a 16 bit value called *option
/// code.*
///
/// The currently assigned option codes can be found in the
/// [IANA registry]. The type is complete as of 2019-12-23.
///
/// [OPT]: ../../opt/index.html
/// [IANA registry]: http://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-11
=>
OptionCode, u16;
/// Long-Lived Queries (LLQ, 1).
///
/// Long-Lived Queries is a protocol developed by Apple for change
/// notifications. It is now being replaced by DNS Push Notifications.
/// The LLQ options is used in LLQ messages.
///
/// This option code and the LLQ option are defined in a upcoming RFC,
/// currently [draft-sekar-dns-llq].
///
/// [draft-sekar-dns-llq]: https://datatracker.ietf.org/doc/draft-sekar-dns-llq/
(Llq => 1, b"LLQ")
/// Update lease (UL, 2).
///
/// This option was proposed in a draft as a way to state lease times for
/// registrations made via DNS UPDATE. Its draft, [draft-sekar-dns-ul],
/// has since expired. The code is considered ‘on hold.’
///
/// [draft-sekar-dns-ul]: http://files.dns-sd.org/draft-sekar-dns-ul.txt
(Ul => 2, b"UL")
/// Name server identifier (NSID, 3).
///
/// The NSID option allows a name server to include an indentifier in an
/// answer for diagnostic purposes. The options in defined in [RFC 5001].
///
/// [RFC 5001]: https://tools.ietf.org/html/rfc5001
(Nsid => 3, b"NSID")
/// DNSSEC algorithm understood (DAU, 5).
///
/// The DAU option allows a validating resolver to signal a queried server
/// which DNSSEC signing algorithms it understands. The option is defined
/// in [RFC 6975].
///
/// [RFC 6075]: https://tools.ietf.org/html/rfc6975
(Dau => 5, b"DAU")
/// DS hash understood (DHU, 6).
///
/// The DHU option allows a validating resolver to signal a queried server
/// which DS hash algorithms it understands. The option is defined
/// in [RFC 6975].
///
/// [RFC 6075]: https://tools.ietf.org/html/rfc6975
(Dhu => 6, b"DHU")
/// NSEC3 hash understood (N3U, 7).
///
/// The DHU option allows a validating resolver to signal a queried server
/// which NSEC3 hash algorithms it understands. The option is defined
/// in [RFC 6975].
///
/// [RFC 6075]: https://tools.ietf.org/html/rfc6975
(N3u => 7, b"N3U")
/// EDNS client subnet (8),
///
/// The EDSN client subnet option allows a resolver to identify the IP
/// address subnet it queries from so that a server can determine the best
/// answer. This option is defined in [RFC 7871].
///
/// [RFC 7871]: https://tools.ietf.org/html/rfc7871
(ClientSubnet => 8, b"edns-client-subnet")
/// Expire (9).
///
/// The expire option allows a secondary to maintain the correct expiry
/// time for a zone when transferring from a server other than the
/// primary. The option is defined in [RFC 7314].
///
/// [RFC 7314]: https://tools.ietf.org/html/rfc7314
(Expire => 9, b"EDNS EXPIRE")
/// DNS Cookie (10).
///
/// The cookie option allows clients and server to exchange session
/// cookies as a mechanism for protecting agains denial-of-service and
/// amplification attacks. The option is defined in [RFC 7873].
///
/// [RFC 7873]: https://tools.ietf.org/html/rfc7873
(Cookie => 10, b"COOKIE")
/// edns-tcp-keepalive (11).
///
/// This option allows DNS servers to signal to a client for how long they
/// may hold open a TCP connection. The option is defined in [RFC 7828].
///
/// [RFC 7828]: https://tools.ietf.org/html/rfc7828
(TcpKeepalive => 11, b"edns-tcp-keepalive")
/// Padding (12).
///
/// The padding option allows clients and servers to pad their messages
/// with extra data to make it harder to guess content based on length.
/// The option is defined in [RFC 7830].
///
/// [RFC 7830]: https://tools.ietf.org/html/rfc7830
(Padding => 12, b"Padding")
/// CHAIN query requests (13).
///
/// The CHAIN query requests option allows a security-aware resolver to
/// all ask a server to include records necessary for DNSSEC validation of
/// the answer. The option is defined in [RFC 7901].
///
/// [RFC 7901]: https://tools.ietf.org/html/rfc7901
(Chain => 13, b"CHAIN")
/// EDNS key tag (14).
///
/// The key tag option allows a client to signal to a server which DNSSEC
/// key they would use to validate an asnwer. The option is defined in
/// [RFC 8145].
///
/// [RFC 8145]: https://tools.ietf.org/html/rfc8145
(KeyTag => 14, b"edns-key-tag")
/// Extended DNS Error (15).
///
/// This option allows the server to return additional information
/// about the cause of DNS errors. It does not change the
/// processing of RCODEs. The option is defined in [RFC 8914].
///
/// [RFC 8914]: https://tools.ietf.org/html/rfc8914
(ExtendedError => 15, b"Extended DNS Error")
/// EDNS client tag (16).
///
/// The client tag option allows a client to send arbitrary additional
/// data to a server. The option is defined in the now expired
/// [draft-bellis-dnsop-edns-tags].
///
/// [draft-bellis-dnsop-edns-tags]: https://datatracker.ietf.org/doc/draft-bellis-dnsop-edns-tags/
(ClientTag => 16, b"EDNS-Client-Tag")
/// EDNS server tag (16).
///
/// The client tag option allows a server to send arbitrary additional
/// data to a client. The option is defined in the now expired
/// [draft-bellis-dnsop-edns-tags].
///
/// [draft-bellis-dnsop-edns-tags]: https://datatracker.ietf.org/doc/draft-bellis-dnsop-edns-tags/
(ServerTag => 17, b"EDNS-Server-Tag")
/// DeviceID (26946).
///
/// Ths option is used by the [Cisco Umbrella network device API].
///
/// [Cisco Umbrella network device API]: https://docs.umbrella.com/developer/networkdevices-api/identifying-dns-traffic2
(DeviceId => 26946, b"DeviceId")
}
int_enum_str_with_decimal!(OptionCode, u16, "unknown option code");
//============ Tests =========================================================
#[cfg(test)]
mod test {
#[cfg(feature = "serde")]
#[test]
fn ser_de() {
use super::OptionCode;
use serde_test::{assert_tokens, Configure, Token};
assert_tokens(
&OptionCode::ServerTag.readable(),
&[Token::Str("EDNS-Server-Tag")],
);
assert_tokens(
&OptionCode::Int(10_000).readable(),
&[Token::U16(10_000)],
);
assert_tokens(&OptionCode::ServerTag.compact(), &[Token::U16(17)]);
assert_tokens(
&OptionCode::Int(10_000).compact(),
&[Token::U16(10_000)],
);
}
}