dns

package
v0.0.0-...-1201bab Latest Latest
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 Go to latest Published: May 27, 2024 License: BSD-3-Clause Imports: 7 Imported by: 6

Documentation

Overview

Code generated by "stringer" command for the types within this file; DO NOT EDIT. and then joined together to keep directory clean. The functions have also been modified to avoid heap allocations. - //go:generate stringer -type=Class -trimprefix=Class -output=string_class.go - //go:generate stringer -type=Type -trimprefix=Type -output=string_type.go - //go:generate stringer -type=OpCode -trimprefix=OpCode -output=string_opcode.go

Index

Constants

View Source 
const (
	// SizeHeader is the length (in bytes) of a DNS header.
	// A header is comprised of 6 uint16s and no padding.
	SizeHeader = 6 * 2
	// The Internet supports name server access using TCP [RFC-9293] on server
	// port 53 (decimal) as well as datagram access using UDP [RFC-768] on UDP port 53 (decimal).
	ServerPort = 53
	ClientPort = 53
	// Messages carried by UDP are restricted to 512 bytes (not counting the IP
	// or UDP headers).  Longer messages are truncated and the TC bit is set in the header.
	MaxSizeUDP = 512
)

Global parameters.

Variables

This section is empty.

Functions

This section is empty.

Types

type Class 

type Class uint16

A Class is a type of network. 

const (
	// ResourceHeader.Class and Question.Class
	ClassINET   Class = 1
	ClassCSNET  Class = 2
	ClassCHAOS  Class = 3
	ClassHESIOD Class = 4

	// Question.Class
	ClassANY Class = 255
)

func (Class) String 

func (i Class) String() string
type Header struct {
	// Generated for any kind of query.  This identifier is copied
	// the corresponding reply and can be used by the requester to
	// match up replies to outstanding queries.
	TransactionID uint16      // 0:2
	Flags         HeaderFlags // 2:4
	// number of entries in the question section.
	QDCount uint16 // 4:6
	// number of resource records in the answer section.
	ANCount uint16 // 6:8
	// number of name server resource records in the authority records section.
	NSCount uint16 // 8:10
	// number of resource records in the additional records section.
	ARCount uint16 // 10:12
}

func DecodeHeader 

func DecodeHeader(b []byte) (dhdr Header)

func (*Header) Put 

func (dhdr *Header) Put(b []byte)

type HeaderFlags 

type HeaderFlags uint16

HeaderFlags gathers the flags in bits 16..31 of the header.

func NewClientHeaderFlags 

func NewClientHeaderFlags(op OpCode, enableRecursion bool) HeaderFlags

NewClientHeaderFlags creates the header flags for a client request.

func (HeaderFlags) IsAuthorativeAnswer 

func (flags HeaderFlags) IsAuthorativeAnswer() bool

IsAuthorativeAnswer returns AA bit which specifies that the responding name server is an authority for the domain name in question section.

func (HeaderFlags) IsRecursionAvailable 

func (flags HeaderFlags) IsRecursionAvailable() bool

IsRecursionAvailable returns RA bit which specifies whether recursive query support is available by the server.

func (HeaderFlags) IsRecursionDesired 

func (flags HeaderFlags) IsRecursionDesired() bool

IsRecursionDesired returns RD bit which specifies whether recursive query support is desired by the client. Is optionally set by client.

func (HeaderFlags) IsResponse 

func (flags HeaderFlags) IsResponse() bool

IsResponse returns QR bit which specifies whether this message is a query (0), or a response (1).

func (HeaderFlags) IsTruncated 

func (flags HeaderFlags) IsTruncated() bool

IsTruncated returns TC bit which specifies that this message was truncated due to length greater than that permitted on the transmission channel.

func (HeaderFlags) OpCode 

func (flags HeaderFlags) OpCode() OpCode

OpCode returns the 4-bit opcode.

func (HeaderFlags) ResponseCode 

func (flags HeaderFlags) ResponseCode() RCode

ResponseCode returns the 4-bit response code set as part of responses.

func (HeaderFlags) String 

func (flags HeaderFlags) String() string

type Message 

type Message struct {
	Header
	Questions   []Question
	Answers     []Resource
	Authorities []Resource
	Additionals []Resource
}

func (*Message) AddQuestions 

func (m *Message) AddQuestions(questions []Question)

func (*Message) AppendTo 

func (m *Message) AppendTo(buf []byte) (_ []byte, err error)

func (*Message) Decode 

func (m *Message) Decode(msg []byte) (_ uint16, incompleteButOK bool, err error)

Decode decodes the DNS message in b into m. It returns the number of bytes consumed from b (0 if no bytes were consumed) and any error encountered. If the message was not completely parsed due to LimitResourceDecoding, incompleteButOK is true and an error is returned, though the message is still usable.

func (*Message) Len 

func (m *Message) Len() uint16

func (*Message) LimitResourceDecoding 

func (m *Message) LimitResourceDecoding(maxQ, maxAns, maxAuth, maxAdd uint16)

func (*Message) Reset 

func (m *Message) Reset()

type Name 

type Name struct {
	// contains filtered or unexported fields
}

func MustNewName 

func MustNewName(s string) Name

func NewName 

func NewName(domain string) (Name, error)

NewName parses a domain name and returns a new Name.

func (*Name) AddLabel 

func (n *Name) AddLabel(label string)

AddLabel adds a label to the name. If n.CanAddLabel(label) returns false, it panics.

func (*Name) AppendDottedTo 

func (n *Name) AppendDottedTo(b []byte) []byte

AppendDottedTo appends the Name to b in dotted format and returns the resulting slice.

func (*Name) AppendTo 

func (n *Name) AppendTo(b []byte) ([]byte, error)

AppendTo appends the Name to b in wire format and returns the resulting slice.

func (*Name) CanAddLabel 

func (n *Name) CanAddLabel(label string) bool

CanAddLabel reports whether the label can be added to the name.

func (*Name) CloneFrom 

func (n *Name) CloneFrom(ex Name)

func (*Name) Decode 

func (n *Name) Decode(b []byte, off uint16) (uint16, error)

Decode resets internal Name buffer and reads raw wire data from buffer, returning any error encountered.

func (*Name) Len 

func (n *Name) Len() uint16

Len returns the length over-the-wire of the encoded Name.

func (*Name) Reset 

func (n *Name) Reset()

Reset resets the Name labels to be empty and reuses buffer.

func (*Name) String 

func (n *Name) String() string

String returns a string representation of the name in dotted format.

func (*Name) VisitLabels 

func (n *Name) VisitLabels(fn func(label []byte)) error

type OpCode 

type OpCode uint16

An OpCode is a DNS operation code which specifies the type of query. 

const (
	OpCodeQuery        OpCode = 0 // Standard query.
	OpCodeInverseQuery OpCode = 1 // Inverse query.
	OpCodeStatus       OpCode = 2 // Server status request.
)

func (OpCode) String 

func (i OpCode) String() string

type Question 

type Question struct {
	Name  Name
	Type  Type
	Class Class
}

func (*Question) Decode 

func (q *Question) Decode(msg []byte, off uint16) (uint16, error)

func (*Question) Len 

func (q *Question) Len() uint16

Len returns Question's length over-the-wire.

func (*Question) Reset 

func (q *Question) Reset()

func (*Question) String 

func (q *Question) String() string

String returns a string representation of the Question with the Name in dotted format.

type RCode 

type RCode uint16

An RCode is a DNS response status code. 

const (
	RCodeSuccess        RCode = 0 // No error condition.
	RCodeFormatError    RCode = 1 // Format error - The name server was unable to interpret the query.
	RCodeServerFailure  RCode = 2 // Server failure - The name server was unable to process this query due to a	problem with the name server.
	RCodeNameError      RCode = 3 // Name Error - Meaningful only for responses from an authoritative name server, this code signifies that the	domain name referenced in the query does not exist.
	RCodeNotImplemented RCode = 4 // Not implemented - The name server does not support the requested kind of query.
	RCodeRefused        RCode = 5 // Refused - The name server refuses to perform the specified operation for policy reasons. For example, a name server may not wish to provide the information to the particular requester, or a name server may not wish to perform a particular operation (e.g., zone transfer) for particular data.
)

/go:generate stringer -type=RCode -trimprefix=RCode -output=rcode_string.go

func (RCode) String 

func (i RCode) String() string

type Resource 

type Resource struct {
	Header ResourceHeader
	// contains filtered or unexported fields
}

func (*Resource) Decode 

func (r *Resource) Decode(b []byte, off uint16) (uint16, error)

func (*Resource) Len 

func (r *Resource) Len() uint16

func (*Resource) RawData 

func (r *Resource) RawData() []byte

func (*Resource) Reset 

func (r *Resource) Reset()

type ResourceHeader 

type ResourceHeader struct {
	Name   Name
	Type   Type
	Class  Class
	TTL    uint32
	Length uint16
}

A ResourceHeader is the header of a DNS resource record. There are many types of DNS resource records, but they all share the same header.

func (*ResourceHeader) Decode 

func (rhdr *ResourceHeader) Decode(msg []byte, off uint16) (uint16, error)

func (*ResourceHeader) Reset 

func (r *ResourceHeader) Reset()

func (*ResourceHeader) String 

func (h *ResourceHeader) String() string

String returns a string representation of the header.

type Type 

type Type uint16

Type is a type of DNS request and response. 

const (
	// ResourceHeader.Type and Question.Type
	TypeA     Type = 1
	TypeNS    Type = 2
	TypeCNAME Type = 5
	TypeSOA   Type = 6
	TypePTR   Type = 12
	TypeMX    Type = 15
	TypeTXT   Type = 16
	TypeAAAA  Type = 28
	TypeSRV   Type = 33
	TypeOPT   Type = 41

	// Question.Type
	TypeWKS   Type = 11
	TypeHINFO Type = 13
	TypeMINFO Type = 14
	TypeAXFR  Type = 252
	TypeALL   Type = 255
)

func (Type) String 

func (i Type) String() string

Source Files

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