Struct DnsName 

pub struct DnsName(/* private fields */);

2.3.1. Preferred name syntax

The DNS specifications attempt to be as general as possible in the rules for constructing domain names. The idea is that the name of any existing object can be expressed as a domain name with minimal changes.

However, when assigning a domain name for an object, the prudent user will select a name which satisfies both the rules of the domain system and any existing rules for the object, whether these rules are published or implied by existing programs.

For example, when naming a mail domain, the user should satisfy both the rules of this memo and those in RFC-822. When creating a new host name, the old rules for HOSTS.TXT should be followed. This avoids problems when old software is converted to use domain names.

The following syntax will result in fewer problems with many

applications that use domain names (e.g., mail, TELNET).

<domain> ::= <subdomain> | " "

<subdomain> ::= <label> | <subdomain> "." <label>

<label> ::= <letter> [ [ <ldh-str> ] <let-dig> ]

<ldh-str> ::= <let-dig-hyp> | <let-dig-hyp> <ldh-str>

<let-dig-hyp> ::= <let-dig> | "-"

<let-dig> ::= <letter> | <digit>

<letter> ::= any one of the 52 alphabetic characters A through Z in upper case and a through z in lower case

<digit> ::= any one of the ten digits 0 through 9

Note that while upper and lower case letters are allowed in domain names, no significance is attached to the case. That is, two names with the same spelling but different case are to be treated as if identical.

The labels must follow the rules for ARPANET host names. They must start with a letter, end with a letter or digit, and have as interior characters only letters, digits, and hyphen. There are also some restrictions on the length. Labels must be 63 characters or less.

For example, the following strings identify hosts in the Internet:

A.ISI.EDU XX.LCS.MIT.EDU SRI-NIC.ARPA

https://datatracker.ietf.org/doc/html/rfc1035#section-2.3.1

Various objects and parameters in the DNS have size limits. They are listed below. Some could be easily changed, others are more fundamental.

• labels: 63 octets or less
• names: 255 octets or less
• TTL: positive values of a signed 32 bit number.
• UDP messages: 512 octets or less

https://datatracker.ietf.org/doc/html/rfc1035#section-2.3.4

Implementations

impl DnsName

pub fn new(value: &str) -> Result<Self, String>

Errors

Returns an error when value is not a valid DNS name.

pub fn read<const N: usize>(buf: &mut FixedBuf<N>) -> Result<DnsName, DnsError>

Errors

Returns an error when buf does not contain a valid name.

pub fn write<const N: usize>( &self, out: &mut FixedBuf<N>, ) -> Result<(), DnsError>

Errors

Returns an error when buf fills up.

pub fn as_bytes(&self) -> Result<FixedBuf<256>, DnsError>

Errors

Returns an error when the name is longer than 255 bytes. This cannot happen.

pub fn inner(&self) -> &str

Trait Implementations

impl Clone for DnsName

fn clone(&self) -> DnsName

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DnsName

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for DnsName

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Hash for DnsName

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for DnsName

fn cmp(&self, other: &DnsName) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for DnsName

fn eq(&self, other: &DnsName) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for DnsName

fn partial_cmp(&self, other: &DnsName) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl TryFrom<&'static str> for DnsName

type Error = String

The type returned in the event of a conversion error.

fn try_from(value: &'static str) -> Result<Self, Self::Error>

Performs the conversion.

impl Eq for DnsName

impl StructuralPartialEq for DnsName