Struct DnsHeader 

pub struct DnsHeader {
    pub id: u16,
    pub flags: Flags,
    pub questions: u16,
    pub answers: u16,
    pub authority: u16,
    pub additional: u16,
}

A DNS header.

The header of a DNS packet follows the following structure:

      0  1  2  3  4  5  6  7  0  1  2  3  4  5  6  7
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                      ID                       |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |QR|   Opcode  |AA|TC|RD|RA| Z|AD|CD|   RCODE   |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                    QDCOUNT                    |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                    ANCOUNT                    |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                    NSCOUNT                    |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                    ARCOUNT                    |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

ID: Random identifier of connnection
QR: Query (0) or Response (1)
OPCODE: Standard query (0), Inverse query (1), Server status query (2), Notify (4), Update (5), DSO (6)
AA: Authoritative Answer
TC: TrunCation
RD: Recursion Desired
RA: Recursion Available
Z: Zero (reserved)
AD: Authentic data (for DNSSEC)
AD: Checking disabled (for DNSSEC)
RCODE: Response code NOERROR (0), FORMERR (1), SERVFAIL (2), NXDOMAIN (3), NOTIMP (4), REFUSED (5)
QDCOUNT: Question records count
ANCOUNT: Answer records count
NSCOUNT: Name server records count
ARCOUNT: Aditional records count

Fields

id: u16

Random identifier of connnection

flags: Flags

The different flags of a DNS header.

questions: u16

Question records count

answers: u16

Answer records count

authority: u16

Name server records count

additional: u16

Aditional records count

Implementations

impl DnsHeader

pub fn serialize(&self, target: &mut Vec<u8>)

Serialize a DnsHeader into a vector of bytes.

Usefult when you need to be able to apend the bytes to an existing Vec<u8, in any other case the From trait is implemented to be able to convert from an DnsHeader to an Vec<u8>.

Trait Implementations

impl Clone for DnsHeader

fn clone(&self) -> DnsHeader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DnsHeader

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

Formats the value using the given formatter.

impl From<&DnsHeader> for Vec<u8>

fn from(header: &DnsHeader) -> Self

Converts to this type from the input type.

impl TryFrom<&[u8]> for DnsHeader

type Error = ParseError

The type returned in the event of a conversion error.

fn try_from(bytes: &[u8]) -> Result<Self, Self::Error>

Performs the conversion.