dns

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 Go to latest Published: Jan 26, 2012 License: BSD-3-Clause Imports: 28 Imported by: 0

README

Alternative (more granular) approach to a DNS library.

Completely usable DNS library. Most widely used Resource Records are supported including the DNSSEC types. It follows a lean and mean philosophy. If there is stuff you should know as a DNS programmer there isn't a convenience function for it. For instance I'm pondering if a zone-like structure should be implemented in the library.

Features:

  • UDP/TCP queries, IPv4 and IPv6;
  • RFC 1035 zone file parsing.
  • Fast, reply speed should be around 30K qps (Faster hardware, even more qps). Parsing RRs (zonefiles) goes with 25K RR/s. This is expected to be optimized further.
  • Client and server side programming (mimicking the http package);
  • Asynchronous queries for client and server;
  • DNSSEC;
  • EDNS0;
  • AXFR/IXFR;
  • TSIG;
  • DNS name compression;

Sample programs can be found in the _examples directory. They can be build with: make examples (after the dns package has been installed)

See this mini howto to get things going.

Have fun!

Miek Gieben - 2010-2012 - miek@miek.nl

Supported RFCs

  • 103{4,5} - DNS standard
  • 1982 - Serial Arithmetic
  • 1876 - LOC record (incomplete)
  • 1995 - IXFR
  • 1996 - DNS notify
  • 2136 - DNS Update (dynamic updates)
  • 2181 - RRset definition
  • 2537 - RSAMD5 DNS keys
  • 2065 - DNSSEC (updated in later RFCs)
  • 2671 - EDNS
  • 2782 - SRV
  • 2845 - TSIG
  • 2915 - NAPTR
  • 3110 - RSASHA1 DNS keys
  • 3225 - DO bit (DNSSEC OK)
  • 340{1,2,3} - NAPTR
  • 3597 - Unkown RRs
  • 403{3,4,5} - DNSSEC + validation functions
  • 4255 - SSHFP
  • 4408 - SPF
  • 4509 - SHA256 Hash in DS
  • 4635 - HMAC SHA TSIG
  • 4892 - id.server
  • 5001 - NSID
  • 5155 - NSEC3
  • 5933 - GOST
  • 5936 - AXFR
  • xxxx - ECDSA

Loosely based upon:

  • ldns
  • NSD
  • Net::DNS
  • GRONG

Documentation

Overview

DOMAIN NAME SYSTEM

Package dns implements a full featured interface to the Domain Name System. The package allows complete control over what is send out to the DNS.

Resource records are native types. They are not stored in wire format. Basic usage pattern for creating a new resource record: 

r := new(RR_TXT)
r.Hdr = RR_Header{Name: "a.miek.nl.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 3600}
r.TXT = "This is the content of the TXT record"

Or directly from a string: 

mx := NewRR("miek.nl. IN MX 10 mx.miek.nl.")

The package dns supports (async) querying/replying, incoming/outgoing Axfr/Ixfr, TSIG, EDNS0, dynamic updates, notifies and DNSSEC validation/signing. Note that domain names MUST be full qualified, before sending them. The packages enforces this, by throwing a panic().

In the DNS messages are exchanged. Use pattern for creating one: 

m := new(Msg)
m.SetQuestion("miek.nl.", TypeMX)

The message m is now a message with the question section set to ask the MX records for the miek.nl. zone.

The following is slightly more verbose, but more flexible: 

m1 := new(Msg)
m1.MsgHdr.Id = Id()
m1.MsgHdr.RecursionDesired = false
m1.Question = make([]Question, 1)
m1.Question[0] = Question{"miek.nl.", TypeMX, ClassINET}

After creating a message it can be send. Basic use pattern for synchronous querying the DNS: 

// We are sending the message 'm' to the server 127.0.0.1
// on port 53 and wait for the reply.
c := NewClient()
// c.Net = "tcp" // If you want to use TCP
in := c.Exchange(m, "127.0.0.1:53")

An asynchronous query is also possible, setting up is more elaborate then a synchronous query. The Basic use pattern is: 

HandleQueryFunc(".", handler)
ListenAndQuery(nil, nil)
c.Do(m1, "127.0.0.1:53")
// Do something else
r := <- DefaultReplyChan
// r.Reply is the answer
// r.Request is the original request

DNSSEC

DNSSEC (DNS Security Extension) adds a layer of security to the DNS. It uses public key cryptography to securely sign resource records. The public keys are stored in DNSKEY records and the signatures in RRSIG records.

TRANSACTION SIGNATURE (TSIG)

A TSIG or transaction signature adds a HMAC TSIG record to each message sent. Basic use pattern when querying with TSIG: 

m := new(Msg)
m.SetAxfr("miek.nl.")
// Add a skeleton TSIG record.
m.SetTsig("axfr.", HmacMD5, 300, uint64(time.Seconds()))
// Generate the contents of the complete TSIG record.
TsigGenerate(m, "so6ZGir4GPAqINNh9U5c3A==", "", false)
// A map holds all the secrets
secrets := make(map[string]string)
secrets["axfr."] = "so6ZGir4GPAqINNh9U5c3A=="        // don't forget the . here

The secrets' map index is set to 'axfr.'. This must match the ownername of the TSIG record, which in the above example, is also set to 'axfr.'

The message requesting an AXFR (almost all TSIG usage is when requesting zone transfers) for miek.nl with the TSIG record added is now ready to use. We now need a new client with access to the secrets: 

c := NewClient()
c.TsigSecret = secrets
err := c.XfrReceive(m, "85.223.71.124:53")

You can now read the records from the AXFR as they come in. Each envelope is checked with TSIG. If something is not correct an error is returned.

Basic use pattern replying to a message that has TSIG set. TODO(mg)

DYNAMIC UPDATES

Dynamic updates reuses the DNS message format, but renames three of the sections. Question is Zone, Answer is Prerequisite, Authority is Update, only the Additional is not renamed. See RFC 2136 for the gory details.

You can set a rather complex set of rules for the existence of absence of certain resource records or names in a zone to specify if resource records should be added or removed. The table from RFC 2136 supplemented with the Go DNS function shows which functions exist to specify the prerequisites.

3.2.4 - Table Of Metavalues Used In Prerequisite Section 

CLASS    TYPE     RDATA    Meaning                    Function
--------------------------------------------------------------
ANY      ANY      empty    Name is in use             NameUsed
ANY      rrset    empty    RRset exists (value indep) RRsetUsedNoRdata
NONE     ANY      empty    Name is not in use         NameNotUsed
NONE     rrset    empty    RRset does not exist       RRsetNotUsed
zone     rrset    rr       RRset exists (value dep)   RRsetUsedRdata

The prerequisite section can also be left empty. If you have decided on the prerequisites you can tell what RRs should be added or deleted. The next table shows the options you have and what functions to call.

3.4.2.6 - Table Of Metavalues Used In Update Section 

CLASS    TYPE     RDATA    Meaning                     Function
---------------------------------------------------------------
ANY      ANY      empty    Delete all RRsets from name NameDelete
ANY      rrset    empty    Delete an RRset             RRsetDelete
NONE     rrset    rr       Delete an RR from  RRset    RRsetDeleteRR
zone     rrset    rr       Add to an RRset             RRsetAddRdata

Index

Constants

View Source 
const (
	Year68            = 1 << 32 // For RFC1982 (Serial Arithmetic) calculations in 32 bits.
	DefaultMsgSize    = 4096    // Standard default for larger than 512 packets.
	UDPReceiveMsgSize = 360     // Default buffer size for servers receiving UDP packets.
	MaxMsgSize        = 65536   // Largest possible DNS packet.
	DefaultTtl        = 3600    // Default TTL.
)
View Source 
const (
	RSAMD5           = 1
	DH               = 2
	DSA              = 3
	ECC              = 4
	RSASHA1          = 5
	DSANSEC3SHA1     = 6
	RSASHA1NSEC3SHA1 = 7
	RSASHA256        = 8
	RSASHA512        = 10
	ECCGOST          = 12
	ECDSAP256SHA256  = 13
	ECDSAP384SHA384  = 14
	PRIVATEDNS       = 253 // Private (experimental keys)
	PRIVATEOID       = 254
)

DNSSEC encryption algorithm codes.

View Source 
const (
	SHA1   // RFC 4034
	SHA256 // RFC 4509
	GOST94 // RFC 5933
	SHA384 // Experimental
)

DNSSEC hashing algorithm codes.

View Source 
const (
	SEP    = 1
	ZONE   = 1 << 7
	REVOKE = 1 << 8
)

DNSKEY flag values.

View Source 
const (
	OptionCodeLLQ  // not used
	OptionCodeUL   // not used
	OptionCodeNSID // NSID, RFC5001

)

EDNS0 Option codes.

View Source 
const (
	NSEC3_NXDOMAIN
	NSEC3_NODATA
)
View Source 
const (
	HmacMD5    = "hmac-md5.sig-alg.reg.int."
	HmacSHA1   = "hmac-sha1."
	HmacSHA256 = "hmac-sha256."
)

HMAC hashing codes. These are transmitted as domain names.

View Source 
const (
	// valid RR_Header.Rrtype and Question.qtype
	TypeA     uint16 = 1
	TypeNS    uint16 = 2
	TypeMD    uint16 = 3
	TypeMF    uint16 = 4
	TypeCNAME uint16 = 5
	TypeSOA   uint16 = 6
	TypeMB    uint16 = 7
	TypeMG    uint16 = 8
	TypeMR    uint16 = 9
	TypeNULL  uint16 = 10
	TypeWKS   uint16 = 11
	TypePTR   uint16 = 12
	TypeHINFO uint16 = 13
	TypeMINFO uint16 = 14
	TypeMX    uint16 = 15
	TypeTXT   uint16 = 16
	TypeAAAA  uint16 = 28
	TypeLOC   uint16 = 29
	TypeSRV   uint16 = 33
	TypeNAPTR uint16 = 35
	TypeKX    uint16 = 36
	TypeCERT  uint16 = 37
	TypeDNAME uint16 = 39

	// EDNS
	TypeOPT uint16 = 41

	TypeSIG        uint16 = 24
	TypeKEY        uint16 = 25
	TypeNXT        uint16 = 30
	TypeDS         uint16 = 43
	TypeSSHFP      uint16 = 44
	TypeIPSECKEY   uint16 = 45 // No type implemented
	TypeRRSIG      uint16 = 46
	TypeNSEC       uint16 = 47
	TypeDNSKEY     uint16 = 48
	TypeDHCID      uint16 = 49
	TypeNSEC3      uint16 = 50
	TypeNSEC3PARAM uint16 = 51
	TypeTALINK     uint16 = 58
	TypeSPF        uint16 = 99

	TypeTKEY uint16 = 249
	TypeTSIG uint16 = 250
	// valid Question.Qtype only
	TypeIXFR  uint16 = 251
	TypeAXFR  uint16 = 252
	TypeMAILB uint16 = 253
	TypeMAILA uint16 = 254
	TypeANY   uint16 = 255
	TypeURI   uint16 = 256
	TypeTA    uint16 = 32768
	TypeDLV   uint16 = 32769
	TypeTLSA  uint16 = 65468 // Experimental

	// valid Question.Qclass
	ClassINET   = 1
	ClassCSNET  = 2
	ClassCHAOS  = 3
	ClassHESIOD = 4
	ClassNONE   = 254
	ClassANY    = 255

	// Msg.rcode
	RcodeSuccess        = 0
	RcodeFormatError    = 1
	RcodeServerFailure  = 2
	RcodeNameError      = 3
	RcodeNotImplemented = 4
	RcodeRefused        = 5
	RcodeYXDomain       = 6
	RcodeYXRrset        = 7
	RcodeNXRrset        = 8
	RcodeNotAuth        = 9
	RcodeNotZone        = 10
	RcodeBadSig         = 16 // TSIG
	RcodeBadKey         = 17
	RcodeBadTime        = 18
	RcodeBadMode        = 19 // TKEY
	RcodeBadName        = 20
	RcodeBadAlg         = 21
	RcodeBadTrunc       = 22 // TSIG

	// Opcode
	OpcodeQuery  = 0
	OpcodeIQuery = 1
	OpcodeStatus = 2
	// There is no 3
	OpcodeNotify = 4
	OpcodeUpdate = 5
)

Wire constants and supported types.

Variables

View Source 
var (
	// DefaultReplyChan is the channel on which the replies are
	// coming back. Is it a channel of *Exchange, so that the original
	// question is included with the answer.
	DefaultReplyChan = newQueryChanSlice()
	// DefaultQueryChan is the channel were you can send the questions to.
	DefaultQueryChan = newQueryChan()
)

Default channels to use for the resolver

View Source 
var (
	ErrUnpack      error = &Error{Err: "unpacking failed"}
	ErrPack        error = &Error{Err: "packing failed"}
	ErrId          error = &Error{Err: "id mismatch"}
	ErrShortRead   error = &Error{Err: "short read"}
	ErrConn        error = &Error{Err: "conn holds both UDP and TCP connection"}
	ErrConnEmpty   error = &Error{Err: "conn has no connection"}
	ErrServ        error = &Error{Err: "no servers could be reached"}
	ErrKey         error = &Error{Err: "bad key"}
	ErrPrivKey     error = &Error{Err: "bad private key"}
	ErrKeySize     error = &Error{Err: "bad key size"}
	ErrKeyAlg      error = &Error{Err: "bad key algorithm"}
	ErrAlg         error = &Error{Err: "bad algorithm"}
	ErrTime        error = &Error{Err: "bad time"}
	ErrNoSig       error = &Error{Err: "no signature found"}
	ErrSig         error = &Error{Err: "bad signature"}
	ErrSecret      error = &Error{Err: "no secret defined"}
	ErrSigGen      error = &Error{Err: "bad signature generation"}
	ErrAuth        error = &Error{Err: "bad authentication"}
	ErrXfrSoa      error = &Error{Err: "no SOA seen"}
	ErrXfrLast     error = &Error{Err: "last SOA"}
	ErrXfrType     error = &Error{Err: "no ixfr, nor axfr"}
	ErrHandle      error = &Error{Err: "handle is nil"}
	ErrChan        error = &Error{Err: "channel is nil"}
	ErrName        error = &Error{Err: "type not found for name"}
	ErrRRset       error = &Error{Err: "invalid rrset"}
	ErrDenialNsec3 error = &Error{Err: "no NSEC3 records"}
	ErrDenialCe    error = &Error{Err: "no matching closest encloser found"}
	ErrDenialNc    error = &Error{Err: "no covering NSEC3 found for next closer"}
	ErrDenialSo    error = &Error{Err: "no covering NSEC3 found for source of synthesis"}
	ErrDenialBit   error = &Error{Err: "type not denied in NSEC3 bitmap"}
)
View Source 
var Alg_str = map[uint8]string{
	RSAMD5:           "RSAMD5",
	DH:               "DH",
	DSA:              "DSA",
	RSASHA1:          "RSASHA1",
	DSANSEC3SHA1:     "DSA-NSEC3-SHA1",
	RSASHA1NSEC3SHA1: "RSASHA1-NSEC3-SHA1",
	RSASHA256:        "RSASHA256",
	RSASHA512:        "RSASHA512",
	ECCGOST:          "ECC-GOST",
	ECDSAP256SHA256:  "ECDSAP256SHA256",
	ECDSAP384SHA384:  "ECDSAP384SHA384",
	PRIVATEDNS:       "PRIVATEDNS",
	PRIVATEOID:       "PRIVATEOID",
}

Map for algorithm names.

View Source 
var Class_str = map[uint16]string{
	ClassINET:   "IN",
	ClassCSNET:  "CS",
	ClassCHAOS:  "CH",
	ClassHESIOD: "HS",
	ClassNONE:   "NONE",
	ClassANY:    "ANY",
}

Map of strings for each CLASS wire type.

View Source 
var DefaultQueryMux = NewQueryMux()

DefaultQueryMux is the default QueryMux used by Query.

View Source 
var DefaultServeMux = NewServeMux()

DefaultServeMux is the default ServeMux used by Serve.

View Source 
var Opcode_str = map[int]string{
	OpcodeQuery:  "QUERY",
	OpcodeIQuery: "IQUERY",
	OpcodeStatus: "STATUS",
	OpcodeNotify: "NOTIFY",
	OpcodeUpdate: "UPDATE",
}

Map of strings for opcodes.

View Source 
var Rcode_str = map[int]string{
	RcodeSuccess:        "NOERROR",
	RcodeFormatError:    "FORMERR",
	RcodeServerFailure:  "SERVFAIL",
	RcodeNameError:      "NXDOMAIN",
	RcodeNotImplemented: "NOTIMPL",
	RcodeRefused:        "REFUSED",
	RcodeYXDomain:       "YXDOMAIN",
	RcodeYXRrset:        "YXRRSET",
	RcodeNXRrset:        "NXRRSET",
	RcodeNotAuth:        "NOTAUTH",
	RcodeNotZone:        "NOTZONE",
}

Map of strings for rcodes.

View Source 
var Rr_str = map[uint16]string{
	TypeCNAME:      "CNAME",
	TypeHINFO:      "HINFO",
	TypeMB:         "MB",
	TypeMG:         "MG",
	TypeMINFO:      "MINFO",
	TypeMR:         "MR",
	TypeMX:         "MX",
	TypeNS:         "NS",
	TypePTR:        "PTR",
	TypeSOA:        "SOA",
	TypeTXT:        "TXT",
	TypeSRV:        "SRV",
	TypeNAPTR:      "NAPTR",
	TypeKX:         "KX",
	TypeCERT:       "CERT",
	TypeDNAME:      "DNAME",
	TypeA:          "A",
	TypeAAAA:       "AAAA",
	TypeLOC:        "LOC",
	TypeOPT:        "OPT",
	TypeDS:         "DS",
	TypeDHCID:      "DHCID",
	TypeIPSECKEY:   "IPSECKEY",
	TypeSSHFP:      "SSHFP",
	TypeRRSIG:      "RRSIG",
	TypeNSEC:       "NSEC",
	TypeDNSKEY:     "DNSKEY",
	TypeNSEC3:      "NSEC3",
	TypeNSEC3PARAM: "NSEC3PARAM",
	TypeTALINK:     "TALINK",
	TypeSPF:        "SPF",
	TypeTKEY:       "TKEY",
	TypeTSIG:       "TSIG",
	TypeAXFR:       "AXFR",
	TypeIXFR:       "IXFR",
	TypeANY:        "ANY",
	TypeURI:        "URI",
	TypeTA:         "TA",
	TypeDLV:        "DLV",
}

Map of strings for each RR wire type.

View Source 
var Str_class = reverseInt16(Class_str)
View Source 
var Str_opcode = reverseInt(Opcode_str)

Map of opcodes strings.

View Source 
var Str_rcode = reverseInt(Rcode_str)

Map of rcodes strings.

View Source 
var Str_rr = reverseInt16(Rr_str)

Reverse, needed for string parsing.

Functions

func CompareLabels 

func CompareLabels(s1, s2 string) (n int)

CompareLabels compares the strings s1 and s2 and returns how many labels they have in common starting from the right. The comparison stops at the first inequality.

www.miek.nl and miek.nl have two labels in common: miek and nl www.miek.nl and www.bla.nl have one label in common: nl

func Fqdn 

func Fqdn(s string) string

Fqdns return the fully qualified domain name from s. Is s is already fq, then it behaves as the identity function.

func Handle 

func Handle(pattern string, handler Handler)

Handle register the handler the given pattern in the DefaultServeMux. The documentation for ServeMux explains how patters are matched.

func HandleFunc 

func HandleFunc(pattern string, handler func(ResponseWriter, *Msg))

func HandleQueryFunc 

func HandleQueryFunc(pattern string, handler func(RequestWriter, *Msg))

func HashName 

func HashName(label string, ha uint8, iter uint16, salt string) string

HashName hashes a string (label) according to RFC5155. It returns the hashed string.

func Id 

func Id() uint16

Id return a 16 bits random number to be used as a message id. The random provided should be good enough.

func IsDomainName 

func IsDomainName(s string) (uint8, bool)

IsDomainName checks if s is a valid domainname, it returns the number of labels and true, when a domain name is valid. When false the returned labelcount isn't specified.

func IsFqdn 

func IsFqdn(s string) bool

IsFqdn checks if a domain name is fully qualified

func ListenAndQuery 

func ListenAndQuery(request chan *Request, handler QueryHandler)

ListenAndQuery starts the listener for firing off the queries. If c is nil DefaultQueryChan is used. If handler is nil DefaultQueryMux is used.

func ListenAndServe 

func ListenAndServe(addr string, network string, handler Handler, size int) error

...

func PackDomainName 

func PackDomainName(s string, msg []byte, off int, compression map[string]int, compress bool) (off1 int, ok bool)

PackDomainName packs a domain name s into msg[off:]. If compression is wanted compress must be true and the compression map, needs to hold a mapping between domain names and offsets pointing into msg[].

func ParseZone 

func ParseZone(r io.Reader, file string) chan Token

ParseZone reads a RFC 1035 zone from r. It returns each parsed RR or on error on the returned channel. The channel t is closed by ParseZone when the end of r is reached.

func RawSetId 

func RawSetId(msg []byte, off int, id uint16) bool

RawSetId sets the message ID in buf. The offset 'off' must be positioned at the beginning of the message.

func RawSetRdlength 

func RawSetRdlength(msg []byte, off, end int) bool

RawSetRdlength sets the rdlength in the header of the RR. The offset 'off' must be positioned at the start of the header of the RR, 'end' must be the end of the RR.

func Refused 

func Refused(w ResponseWriter, r *Msg)

Helper handler that returns an answer with RCODE = refused for every request.

func SplitLabels 

func SplitLabels(s string) []string

SplitLabels splits a domainname string into its labels.

func TsigGenerate 

func TsigGenerate(m *Msg, secret, requestMAC string, timersOnly bool) error

TsigGenerate adds an TSIG RR to a message. The TSIG MAC is saved in the Tsig RR that is added. When TsigGenerate is called for the first time requestMAC is set to the empty string. If something goes wrong an error is returned, otherwise it is nil.

func TsigVerify 

func TsigVerify(msg []byte, secret, requestMAC string, timersOnly bool) error

TsigVerify verifies the TSIG on a message. If the signature does not validate err contains the error, otherwise it is nil.

func UnpackDomainName 

func UnpackDomainName(msg []byte, off int) (s string, off1 int, ok bool)

UnpackDomainName unpack a domain name.

func XfrSend 

func XfrSend(w ResponseWriter, q *Msg, a string) error

XfrSend performs an outgoing Ixfr or Axfr. The function is xfr agnostic, it is up to the caller to correctly send the sequence of messages.

Types

type Client 

type Client struct {
	Net          string            // if "tcp" a TCP query will be initiated, otherwise an UDP one
	Attempts     int               // number of attempts
	Retry        bool              // retry with TCP
	QueryChan    chan *Request     // read DNS request from this channel
	ReplyChan    chan *Exchange    // write the reply (together with the DNS request) to this channel
	ReadTimeout  time.Duration     // the net.Conn.SetReadTimeout value for new connections (ns)
	WriteTimeout time.Duration     // the net.Conn.SetWriteTimeout value for new connections (ns)
	TsigSecret   map[string]string // secret(s) for Tsig map[<zonename>]<base64 secret>
	Hijacked     net.Conn          // if set the calling code takes care of the connection

}

func NewClient 

func NewClient() *Client

NewClient creates a new client, with Net set to "udp" and Attempts to 1. The client's ReplyChan is set to DefaultReplyChan and QueryChan to DefaultQueryChan.

func (*Client) Do 

func (c *Client) Do(m *Msg, a string)

Do performs an asynchronous query. The result is returned on the QueryChan channel set in the Client c.

func (*Client) Exchange 

func (c *Client) Exchange(m *Msg, a string) (r *Msg, err error)

Exchange performs an synchronous query. It sends the message m to the address contained in a and waits for an reply.

func (*Client) ExchangeBuffer 

func (c *Client) ExchangeBuffer(inbuf []byte, a string, outbuf []byte) (n int, err error)

ExchangeBuffer performs a synchronous query. It sends the buffer m to the address contained in a.

func (*Client) XfrReceive 

func (c *Client) XfrReceive(q *Msg, a string) error

XfrReceives requests an incoming Ixfr or Axfr. If the message q's question section contains an AXFR type an Axfr is performed, if it is IXFR it does an Ixfr. Each message will be send along the Client's reply channel as it is received. The last message send has Exchange.Error set to ErrXfrLast to signal there is nothing more to come.

type ClientConfig 

type ClientConfig struct {
	Servers  []string // servers to use
	Search   []string // suffixes to append to local name
	Port     string   // what port to use
	Ndots    int      // number of dots in name to trigger absolute lookup
	Timeout  int      // seconds before giving up on packet
	Attempts int      // lost packets before giving up on server
}

Wraps the contents of the /etc/resolv.conf.

func ClientConfigFromFile 

func ClientConfigFromFile(conf string) (*ClientConfig, error)

ClientConfigFromFile parses a resolv.conf(5) like file and returns a *ClientConfig.

type Error 

type Error struct {
	Err     string
	Name    string
	Server  net.Addr
	Timeout bool
}

Error represents a DNS error

func (*Error) Error 

func (e *Error) Error() string

type Exchange 

type Exchange struct {
	Request *Msg  // The question sent.
	Reply   *Msg  // The answer to the question that was sent.
	Error   error // If something went wrong, this contains the error.
}

Exchange is used in communicating with the resolver.

type Handler 

type Handler interface {
	ServeDNS(w ResponseWriter, r *Msg)
}

func RefusedHandler 

func RefusedHandler() Handler

RefusedHandler returns HandlerFunc with Refused.

type HandlerFunc 

type HandlerFunc func(ResponseWriter, *Msg)

The HandlerFunc type is an adapter to allow the use of ordinary functions as DNS handlers. If f is a function with the appropriate signature, HandlerFunc(f) is a Handler object that calls f.

func (HandlerFunc) ServeDNS 

func (f HandlerFunc) ServeDNS(w ResponseWriter, r *Msg)

ServerDNS calls f(w, r)

type HandlerQueryFunc 

type HandlerQueryFunc func(RequestWriter, *Msg)

The HandlerQueryFunc type is an adapter to allow the use of ordinary functions as DNS query handlers. If f is a function with the appropriate signature, HandlerQueryFunc(f) is a QueryHandler object that calls f.

func (HandlerQueryFunc) QueryDNS 

func (f HandlerQueryFunc) QueryDNS(w RequestWriter, r *Msg)

QueryDNS calls f(w, reg) 

type Header struct {
	Id                                 uint16
	Bits                               uint16
	Qdcount, Ancount, Nscount, Arcount uint16
}

The wire format for the DNS packet header.

type Msg 

type Msg struct {
	MsgHdr
	Compress bool // If true, the message will be compressed when converted to wire format.
	Question []Question
	Answer   []RR
	Ns       []RR
	Extra    []RR
}

The layout of a DNS message.

func NewUpdate 

func NewUpdate(zone string, class uint16) *Msg

NewUpdate creates a new DNS update packet. This returns a normal dns *Msg, but sets some options.

func (*Msg) CompressedLen 

func (dns *Msg) CompressedLen() int

CompressedLen returns the length of the message when in compressed wire format.

func (*Msg) IsAxfr 

func (dns *Msg) IsAxfr() (ok bool)

IsAxfr checks if the message is a valid axfr request packet.

func (*Msg) IsEdns0 

func (dns *Msg) IsEdns0() (ok bool)

IsEdns0 checks if the message has a Edns0 record, any EDNS0 record in the additional section will do

func (*Msg) IsIxfr 

func (dns *Msg) IsIxfr() (ok bool)

IsIXfr checks if the message is a valid ixfr request packet.

func (*Msg) IsNotify 

func (dns *Msg) IsNotify() (ok bool)

IsNotify checks if the message is a valid notify packet.

func (*Msg) IsQuestion 

func (dns *Msg) IsQuestion() (ok bool)

IsQuestion returns true if the packet is a question.

func (*Msg) IsRcode 

func (dns *Msg) IsRcode(rcode int) (ok bool)

IsRcode checks if the header of the packet has rcode set.

func (*Msg) IsRcodeFormatError 

func (dns *Msg) IsRcodeFormatError() (ok bool)

IsRcodeFormatError checks if the message has FormErr set.

func (*Msg) IsTsig 

func (dns *Msg) IsTsig() (ok bool)

IsTsig checks if the message has a TSIG record as the last record in the additional section.

func (*Msg) IsUpdate 

func (dns *Msg) IsUpdate() (ok bool)

IsUpdate checks if the message is a dynamic update packet.

func (*Msg) Len 

func (dns *Msg) Len() int

Len return the message length when in uncompressed wire format.

func (*Msg) NameDelete 

func (u *Msg) NameDelete(rr []RR)

NameDelete deletes all RRsets of a name, see RFC 2136 section 2.5.3

func (*Msg) NameNotUsed 

func (u *Msg) NameNotUsed(rr []RR)

NameNotUsed sets the RRs in the prereq section to "Name is in not use" RRs. RFC 2136 section 2.4.5.

func (*Msg) NameUsed 

func (u *Msg) NameUsed(rr []RR)

NameUsed sets the RRs in the prereq section to "Name is in use" RRs. RFC 2136 section 2.4.4.

func (*Msg) Nsec3Verify 

func (m *Msg) Nsec3Verify(q Question) (int, error)

Nsec3Verify verifies an denial of existence response with NSEC3s. This function does not validate the NSEC3s.

func (*Msg) NsecVerify 

func (m *Msg) NsecVerify(q Question) error

NsecVerify verifies an denial of existence response with NSECs NsecVerify returns nil when the NSECs in the message contain the correct proof. This function does not validates the NSECs.

func (*Msg) Pack 

func (dns *Msg) Pack() (msg []byte, ok bool)

Pack a msg: convert it to wire format.

func (*Msg) RRsetAddRdata 

func (u *Msg) RRsetAddRdata(rr []RR)

RRsetAddRdata adds an complete RRset, see RFC 2136 section 2.5.1

func (*Msg) RRsetDelete 

func (u *Msg) RRsetDelete(rr []RR)

RRsetDelete deletes an RRset, see RFC 2136 section 2.5.2

func (*Msg) RRsetDeleteRR 

func (u *Msg) RRsetDeleteRR(rr []RR)

RRsetDeleteRR deletes RR from the RRSset, see RFC 2136 section 2.5.4

func (*Msg) RRsetNotUsed 

func (u *Msg) RRsetNotUsed(rr []RR)

RRsetNotUsed sets the RRs in the prereq section to "RRset does not exist" RRs. RFC 2136 section 2.4.3.

func (*Msg) RRsetUsedNoRdata 

func (u *Msg) RRsetUsedNoRdata(rr []RR)

RRsetUsedNoRdata sets the RRs in the prereq section to "RRset exists (value independent -- no rdata)" RRs. RFC 2136 section 2.4.1.

func (*Msg) RRsetUsedRdata 

func (u *Msg) RRsetUsedRdata(rr []RR)

RRsetUsedRdata sets the RRs in the prereq section to "RRset exists (value dependent -- with rdata)" RRs. RFC 2136 section 2.4.2.

func (*Msg) SetAxfr 

func (dns *Msg) SetAxfr(z string)

SetAxfr creates dns msg suitable for requesting an axfr.

func (*Msg) SetEdns0 

func (dns *Msg) SetEdns0(udpsize uint16, do bool)

SetEdns0 appends a EDNS0 OPT RR to the message. TSIG should always the last RR in a message.

func (*Msg) SetIxfr 

func (dns *Msg) SetIxfr(z string, serial uint32)

SetIxfr creates dns msg suitable for requesting an ixfr.

func (*Msg) SetNotify 

func (dns *Msg) SetNotify(z string)

SetNotify creates a notify packet.

func (*Msg) SetQuestion 

func (dns *Msg) SetQuestion(z string, t uint16)

SetQuestion creates a question packet.

func (*Msg) SetRcode 

func (dns *Msg) SetRcode(request *Msg, rcode int)

SetRcode creates an error packet.

func (*Msg) SetRcodeFormatError 

func (dns *Msg) SetRcodeFormatError(request *Msg)

SetRcodeFormatError creates a packet with FormError set.

func (*Msg) SetReply 

func (dns *Msg) SetReply(request *Msg)

SetReply creates a reply packet from a request message.

func (*Msg) SetTsig 

func (dns *Msg) SetTsig(z, algo string, fudge uint16, timesigned uint64)

SetTsig appends a TSIG RR to the message. This is only a skeleton Tsig RR that is added as the last RR in the additional section. The caller should then call TsigGenerate, to generate the complete TSIG with the secret.

func (*Msg) SetUpdate 

func (dns *Msg) SetUpdate(z string)

SetUpdate makes the message a dynamic update packet. It sets the ZONE section to: z, TypeSOA, classINET.

func (*Msg) String 

func (dns *Msg) String() string

Convert a complete message to a string with dig-like output.

func (*Msg) Unpack 

func (dns *Msg) Unpack(msg []byte) bool

Unpack a binary message to a Msg structure.

type MsgHdr 

type MsgHdr struct {
	Id                 uint16
	Response           bool
	Opcode             int
	Authoritative      bool
	Truncated          bool
	RecursionDesired   bool
	RecursionAvailable bool
	Zero               bool
	AuthenticatedData  bool
	CheckingDisabled   bool
	Rcode              int
}

A manually-unpacked version of (id, bits). This is in its own struct for easy printing.

func (*MsgHdr) String 

func (h *MsgHdr) String() string

Convert a MsgHdr to a string, mimic the way Dig displays headers:

;; opcode: QUERY, status: NOERROR, id: 48404

;; flags: qr aa rd ra;

type Option 

type Option struct {
	Code uint16
	Data string "hex"
}

An ENDS0 option rdata element.

type ParseError 

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

ParseError contains the parse error and the location in the io.Reader where the error occured.

func (*ParseError) Error 

func (e *ParseError) Error() (s string)

type PrivateKey 

type PrivateKey interface{}

Empty interface that is used as a wrapper around all possible private key implementations from the crypto package.

func ReadPrivateKey 

func ReadPrivateKey(q io.Reader, file string) (PrivateKey, error)

ReadPrivateKey reads a private key from the io.Reader q.

type Query 

type Query struct {
	QueryChan chan *Request // read DNS request from this channel
	Handler   QueryHandler  // handler to invoke, dns.DefaultQueryMux if nil
}

func (*Query) ListenAndQuery 

func (q *Query) ListenAndQuery() error

func (*Query) Query 

func (q *Query) Query() error

type QueryHandler 

type QueryHandler interface {
	QueryDNS(w RequestWriter, q *Msg)
}

Incoming (just as in os.Signal)

type QueryMux 

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

QueryMux is an DNS request multiplexer. It matches the zone name of each incoming request against a list of registered patterns add calls the handler for the pattern that most closely matches the zone name.

func NewQueryMux 

func NewQueryMux() *QueryMux

NewQueryMux allocates and returns a new QueryMux.

func (*QueryMux) Handle 

func (mux *QueryMux) Handle(pattern string, handler QueryHandler)

func (*QueryMux) HandleQueryFunc 

func (mux *QueryMux) HandleQueryFunc(pattern string, handler func(RequestWriter, *Msg))

func (*QueryMux) QueryDNS 

func (mux *QueryMux) QueryDNS(w RequestWriter, r *Msg)

type Question 

type Question struct {
	Name   string "cdomain-name" // "cdomain-name" specifies encoding (and may be compressed)
	Qtype  uint16
	Qclass uint16
}

DNS queries.

func (*Question) Len 

func (q *Question) Len() int

func (*Question) String 

func (q *Question) String() (s string)

type RR 

type RR interface {
	Header() *RR_Header
	String() string
	Len() int
}

func NewRR 

func NewRR(s string) (RR, error)

NewRR reads the RR contained in the string s. Only the first RR is returned. The class defaults to IN and TTL defaults to DefaultTtl

func ReadRR 

func ReadRR(q io.Reader, filename string) (RR, error)

ReadRR reads the RR contained in q. Only the first RR is returned. The class defaults to IN and TTL defaults to DefaultTtl

type RR_A 

type RR_A struct {
	Hdr RR_Header
	A   net.IP "A"
}

func (*RR_A) Header 

func (rr *RR_A) Header() *RR_Header

func (*RR_A) Len 

func (rr *RR_A) Len() int

func (*RR_A) String 

func (rr *RR_A) String() string

type RR_AAAA 

type RR_AAAA struct {
	Hdr  RR_Header
	AAAA net.IP "AAAA"
}

func (*RR_AAAA) Header 

func (rr *RR_AAAA) Header() *RR_Header

func (*RR_AAAA) Len 

func (rr *RR_AAAA) Len() int

func (*RR_AAAA) String 

func (rr *RR_AAAA) String() string

type RR_ANY 

type RR_ANY struct {
	Hdr RR_Header
}

func (*RR_ANY) Header 

func (rr *RR_ANY) Header() *RR_Header

func (*RR_ANY) Len 

func (rr *RR_ANY) Len() int

func (*RR_ANY) String 

func (rr *RR_ANY) String() string

type RR_CERT 

type RR_CERT struct {
	Hdr         RR_Header
	Type        uint16
	KeyTag      uint16
	Algorithm   uint8
	Certificate string "base64"
}

See RFC 4398.

func (*RR_CERT) Header 

func (rr *RR_CERT) Header() *RR_Header

func (*RR_CERT) Len 

func (rr *RR_CERT) Len() int

func (*RR_CERT) String 

func (rr *RR_CERT) String() string

type RR_CNAME 

type RR_CNAME struct {
	Hdr   RR_Header
	Cname string "cdomain-name"
}

func (*RR_CNAME) Header 

func (rr *RR_CNAME) Header() *RR_Header

func (*RR_CNAME) Len 

func (rr *RR_CNAME) Len() int

func (*RR_CNAME) String 

func (rr *RR_CNAME) String() string

type RR_DHCID 

type RR_DHCID struct {
	Hdr    RR_Header
	Digest string "base64"
}

func (*RR_DHCID) Header 

func (rr *RR_DHCID) Header() *RR_Header

func (*RR_DHCID) Len 

func (rr *RR_DHCID) Len() int

func (*RR_DHCID) String 

func (rr *RR_DHCID) String() string

type RR_DLV 

type RR_DLV struct {
	Hdr        RR_Header
	KeyTag     uint16
	Algorithm  uint8
	DigestType uint8
	Digest     string "hex"
}

func (*RR_DLV) Header 

func (rr *RR_DLV) Header() *RR_Header

func (*RR_DLV) Len 

func (rr *RR_DLV) Len() int

func (*RR_DLV) String 

func (rr *RR_DLV) String() string

type RR_DNAME 

type RR_DNAME struct {
	Hdr    RR_Header
	Target string "domain-name"
}

See RFC 2672.

func (*RR_DNAME) Header 

func (rr *RR_DNAME) Header() *RR_Header

func (*RR_DNAME) Len 

func (rr *RR_DNAME) Len() int

func (*RR_DNAME) String 

func (rr *RR_DNAME) String() string

type RR_DNSKEY 

type RR_DNSKEY struct {
	Hdr       RR_Header
	Flags     uint16
	Protocol  uint8
	Algorithm uint8
	PublicKey string "base64"
}

func (*RR_DNSKEY) Generate 

func (r *RR_DNSKEY) Generate(bits int) (PrivateKey, error)

Generate generates a DNSKEY of the given bit size. The public part is put inside the DNSKEY record. The Algorithm in the key must be set as this will define what kind of DNSKEY will be generated. The ECDSA algorithms imply a fixed keysize, in that case bits should be set to the size of the algorithm.

func (*RR_DNSKEY) Header 

func (rr *RR_DNSKEY) Header() *RR_Header

func (*RR_DNSKEY) KeyTag 

func (k *RR_DNSKEY) KeyTag() uint16

KeyTag calculates the keytag (or key-id) of the DNSKEY.

func (*RR_DNSKEY) Len 

func (rr *RR_DNSKEY) Len() int

func (*RR_DNSKEY) PrivateKeyString 

func (r *RR_DNSKEY) PrivateKeyString(p PrivateKey) (s string)

PrivateKeyString converts a PrivateKey to a string. This string has the same format as the private-key-file of BIND9 (Private-key-format: v1.3). It needs some info from the key (hashing, keytag), so its a method of the RR_DNSKEY.

func (*RR_DNSKEY) String 

func (rr *RR_DNSKEY) String() string

func (*RR_DNSKEY) ToDS 

func (k *RR_DNSKEY) ToDS(h int) *RR_DS

ToDS converts a DNSKEY record to a DS record.

type RR_DS 

type RR_DS struct {
	Hdr        RR_Header
	KeyTag     uint16
	Algorithm  uint8
	DigestType uint8
	Digest     string "hex"
}

func (*RR_DS) Header 

func (rr *RR_DS) Header() *RR_Header

func (*RR_DS) Len 

func (rr *RR_DS) Len() int

func (*RR_DS) String 

func (rr *RR_DS) String() string

type RR_HINFO 

type RR_HINFO struct {
	Hdr RR_Header
	Cpu string
	Os  string
}

func (*RR_HINFO) Header 

func (rr *RR_HINFO) Header() *RR_Header

func (*RR_HINFO) Len 

func (rr *RR_HINFO) Len() int

func (*RR_HINFO) String 

func (rr *RR_HINFO) String() string

type RR_Header 

type RR_Header struct {
	Name     string "cdomain-name"
	Rrtype   uint16
	Class    uint16
	Ttl      uint32
	Rdlength uint16 // length of data after header
}

DNS resource records. There are many types of messages, but they all share the same header.

func (*RR_Header) Header 

func (h *RR_Header) Header() *RR_Header

func (*RR_Header) Len 

func (h *RR_Header) Len() int

func (*RR_Header) String 

func (h *RR_Header) String() string

type RR_KX 

type RR_KX struct {
	Hdr        RR_Header
	Preference uint16
	Exchanger  string "domain-name"
}

func (*RR_KX) Header 

func (rr *RR_KX) Header() *RR_Header

func (*RR_KX) Len 

func (rr *RR_KX) Len() int

func (*RR_KX) String 

func (rr *RR_KX) String() string

type RR_LOC 

type RR_LOC struct {
	Hdr       RR_Header
	Version   uint8
	Size      uint8
	HorizPre  uint8
	VertPre   uint8
	Latitude  uint32
	Longitude uint32
	Altitude  uint32
}

func (*RR_LOC) Header 

func (rr *RR_LOC) Header() *RR_Header

func (*RR_LOC) Len 

func (rr *RR_LOC) Len() int

func (*RR_LOC) String 

func (rr *RR_LOC) String() string

type RR_MB 

type RR_MB struct {
	Hdr RR_Header
	Mb  string "cdomain-name"
}

func (*RR_MB) Header 

func (rr *RR_MB) Header() *RR_Header

func (*RR_MB) Len 

func (rr *RR_MB) Len() int

func (*RR_MB) String 

func (rr *RR_MB) String() string

type RR_MG 

type RR_MG struct {
	Hdr RR_Header
	Mg  string "cdomain-name"
}

func (*RR_MG) Header 

func (rr *RR_MG) Header() *RR_Header

func (*RR_MG) Len 

func (rr *RR_MG) Len() int

func (*RR_MG) String 

func (rr *RR_MG) String() string

type RR_MINFO 

type RR_MINFO struct {
	Hdr   RR_Header
	Rmail string "cdomain-name"
	Email string "cdomain-name"
}

func (*RR_MINFO) Header 

func (rr *RR_MINFO) Header() *RR_Header

func (*RR_MINFO) Len 

func (rr *RR_MINFO) Len() int

func (*RR_MINFO) String 

func (rr *RR_MINFO) String() string

type RR_MR 

type RR_MR struct {
	Hdr RR_Header
	Mr  string "cdomain-name"
}

func (*RR_MR) Header 

func (rr *RR_MR) Header() *RR_Header

func (*RR_MR) Len 

func (rr *RR_MR) Len() int

func (*RR_MR) String 

func (rr *RR_MR) String() string

type RR_MX 

type RR_MX struct {
	Hdr  RR_Header
	Pref uint16
	Mx   string "cdomain-name"
}

func (*RR_MX) Header 

func (rr *RR_MX) Header() *RR_Header

func (*RR_MX) Len 

func (rr *RR_MX) Len() int

func (*RR_MX) String 

func (rr *RR_MX) String() string

type RR_NAPTR 

type RR_NAPTR struct {
	Hdr         RR_Header
	Order       uint16
	Preference  uint16
	Flags       string
	Service     string
	Regexp      string
	Replacement string "domain-name"
}

func (*RR_NAPTR) Header 

func (rr *RR_NAPTR) Header() *RR_Header

func (*RR_NAPTR) Len 

func (rr *RR_NAPTR) Len() int

func (*RR_NAPTR) String 

func (rr *RR_NAPTR) String() string

type RR_NS 

type RR_NS struct {
	Hdr RR_Header
	Ns  string "cdomain-name"
}

func (*RR_NS) Header 

func (rr *RR_NS) Header() *RR_Header

func (*RR_NS) Len 

func (rr *RR_NS) Len() int

func (*RR_NS) String 

func (rr *RR_NS) String() string

type RR_NSEC 

type RR_NSEC struct {
	Hdr        RR_Header
	NextDomain string   "domain-name"
	TypeBitMap []uint16 "NSEC"
}

func (*RR_NSEC) Header 

func (rr *RR_NSEC) Header() *RR_Header

func (*RR_NSEC) Len 

func (rr *RR_NSEC) Len() int

func (*RR_NSEC) String 

func (rr *RR_NSEC) String() string

type RR_NSEC3 

type RR_NSEC3 struct {
	Hdr        RR_Header
	Hash       uint8
	Flags      uint8
	Iterations uint16
	SaltLength uint8
	Salt       string "size-hex"
	HashLength uint8
	NextDomain string   "size-base32"
	TypeBitMap []uint16 "NSEC"
}

func (*RR_NSEC3) Cover 

func (nsec3 *RR_NSEC3) Cover(domain string) bool

Cover checks if domain is covered by the NSEC3 record, domain must be given in plain text.

func (*RR_NSEC3) HashNames 

func (nsec3 *RR_NSEC3) HashNames(zone string)

HashNames hashes the ownername and the next owner name in an NSEC3 record according to RFC 5155. It uses the paramaters as set in the NSEC3 record. The string zone is appended to the hashed ownername.

func (*RR_NSEC3) Header 

func (rr *RR_NSEC3) Header() *RR_Header

func (*RR_NSEC3) Len 

func (rr *RR_NSEC3) Len() int

func (*RR_NSEC3) Match 

func (nsec3 *RR_NSEC3) Match(domain string) bool

Match checks if domain matches the first (hashed) owner name of the NSEC3 record, domain must be given in plain text.

func (*RR_NSEC3) String 

func (rr *RR_NSEC3) String() string

type RR_NSEC3PARAM 

type RR_NSEC3PARAM struct {
	Hdr        RR_Header
	Hash       uint8
	Flags      uint8
	Iterations uint16
	SaltLength uint8
	Salt       string "hex" // hexsize??
}

func (*RR_NSEC3PARAM) Header 

func (rr *RR_NSEC3PARAM) Header() *RR_Header

func (*RR_NSEC3PARAM) Len 

func (rr *RR_NSEC3PARAM) Len() int

func (*RR_NSEC3PARAM) String 

func (rr *RR_NSEC3PARAM) String() string

type RR_OPT 

type RR_OPT struct {
	Hdr    RR_Header
	Option []Option "OPT" // tag is used in Pack and Unpack
}

Adding an EDNS0 record to a message is done as follows: 

opt := new(RR_OPT)
opt.Hdr = dns.RR_Header{Name: "", Rrtype: TypeOPT}
opt.SetVersion(0)       // set version to zero
opt.SetDo()             // set the DO bit
opt.SetUDPSize(4096)    // set the message size
m.Extra = make([]RR, 1)
m.Extra[0] = opt        // add OPT RR to the message

func (*RR_OPT) Do 

func (rr *RR_OPT) Do() bool

Do gets the value of the DO (DNSSEC OK) bit.

func (*RR_OPT) Header 

func (rr *RR_OPT) Header() *RR_Header

func (*RR_OPT) Len 

func (rr *RR_OPT) Len() int

func (*RR_OPT) Nsid 

func (rr *RR_OPT) Nsid() string

Nsid returns the NSID as hex character string.

func (*RR_OPT) SetDo 

func (rr *RR_OPT) SetDo()

SetDo sets the DO (DNSSEC OK) bit.

func (*RR_OPT) SetNsid 

func (rr *RR_OPT) SetNsid(hexnsid string)

SetNsid sets the NSID from a hex character string. Use the empty string when requesting an NSID.

func (*RR_OPT) SetUDPSize 

func (rr *RR_OPT) SetUDPSize(size uint16)

SetUDPSize sets the UDP buffer size.

func (*RR_OPT) SetVersion 

func (rr *RR_OPT) SetVersion(v uint8)

SetVersion sets the version of EDNS. This is usually zero.

func (*RR_OPT) String 

func (rr *RR_OPT) String() string

func (*RR_OPT) UDPSize 

func (rr *RR_OPT) UDPSize() uint16

UDPSize gets the UDP buffer size.

func (*RR_OPT) Version 

func (rr *RR_OPT) Version() uint8

Version returns the EDNS version.

type RR_PTR 

type RR_PTR struct {
	Hdr RR_Header
	Ptr string "cdomain-name"
}

func (*RR_PTR) Header 

func (rr *RR_PTR) Header() *RR_Header

func (*RR_PTR) Len 

func (rr *RR_PTR) Len() int

func (*RR_PTR) String 

func (rr *RR_PTR) String() string

type RR_RFC3597 

type RR_RFC3597 struct {
	Hdr   RR_Header
	Rdata string "hex"
}

Unknown RR representation

func (*RR_RFC3597) Header 

func (rr *RR_RFC3597) Header() *RR_Header

func (*RR_RFC3597) Len 

func (rr *RR_RFC3597) Len() int

func (*RR_RFC3597) String 

func (rr *RR_RFC3597) String() string

type RR_RRSIG 

type RR_RRSIG struct {
	Hdr         RR_Header
	TypeCovered uint16
	Algorithm   uint8
	Labels      uint8
	OrigTtl     uint32
	Expiration  uint32
	Inception   uint32
	KeyTag      uint16
	SignerName  string "domain-name"
	Signature   string "base64"
}

func (*RR_RRSIG) Header 

func (rr *RR_RRSIG) Header() *RR_Header

func (*RR_RRSIG) Len 

func (rr *RR_RRSIG) Len() int

func (*RR_RRSIG) Sign 

func (s *RR_RRSIG) Sign(k PrivateKey, rrset RRset) error

Sign signs an RRSet. The signature needs to be filled in with the values: Inception, Expiration, KeyTag, SignerName and Algorithm. The rest is copied from the RRset. Sign returns true when the signing went OK, otherwise false. The signature data in the RRSIG is filled by this method. There is no check if RRSet is a proper (RFC 2181) RRSet.

func (*RR_RRSIG) String 

func (rr *RR_RRSIG) String() string

func (*RR_RRSIG) ValidityPeriod 

func (s *RR_RRSIG) ValidityPeriod() bool

ValidityPeriod uses RFC1982 serial arithmetic to calculate if a signature period is valid.

func (*RR_RRSIG) Verify 

func (s *RR_RRSIG) Verify(k *RR_DNSKEY, rrset RRset) error

Verify validates an RRSet with the signature and key. This is only the cryptographic test, the signature validity period most be checked separately.

type RR_SOA 

type RR_SOA struct {
	Hdr     RR_Header
	Ns      string "cdomain-name"
	Mbox    string "cdomain-name"
	Serial  uint32
	Refresh uint32
	Retry   uint32
	Expire  uint32
	Minttl  uint32
}

func (*RR_SOA) Header 

func (rr *RR_SOA) Header() *RR_Header

func (*RR_SOA) Len 

func (rr *RR_SOA) Len() int

func (*RR_SOA) String 

func (rr *RR_SOA) String() string

type RR_SPF 

type RR_SPF struct {
	Hdr RR_Header
	Txt string
}

See RFC 4408.

func (*RR_SPF) Header 

func (rr *RR_SPF) Header() *RR_Header

func (*RR_SPF) Len 

func (rr *RR_SPF) Len() int

func (*RR_SPF) String 

func (rr *RR_SPF) String() string

type RR_SRV 

type RR_SRV struct {
	Hdr      RR_Header
	Priority uint16
	Weight   uint16
	Port     uint16
	Target   string "domain-name"
}

func (*RR_SRV) Header 

func (rr *RR_SRV) Header() *RR_Header

func (*RR_SRV) Len 

func (rr *RR_SRV) Len() int

func (*RR_SRV) String 

func (rr *RR_SRV) String() string

type RR_SSHFP 

type RR_SSHFP struct {
	Hdr         RR_Header
	Algorithm   uint8
	Type        uint8
	FingerPrint string "hex"
}

func (*RR_SSHFP) Header 

func (rr *RR_SSHFP) Header() *RR_Header

func (*RR_SSHFP) Len 

func (rr *RR_SSHFP) Len() int

func (*RR_SSHFP) String 

func (rr *RR_SSHFP) String() string

type RR_TA 

type RR_TA struct {
	Hdr        RR_Header
	KeyTag     uint16
	Algorithm  uint8
	DigestType uint8
	Digest     string "hex"
}

func (*RR_TA) Header 

func (rr *RR_TA) Header() *RR_Header

func (*RR_TA) Len 

func (rr *RR_TA) Len() int

func (*RR_TA) String 

func (rr *RR_TA) String() string
type RR_TALINK struct {
	Hdr          RR_Header
	PreviousName string "domain"
	NextName     string "domain"
}

func (*RR_TALINK) Header 

func (rr *RR_TALINK) Header() *RR_Header

func (*RR_TALINK) Len 

func (rr *RR_TALINK) Len() int

func (*RR_TALINK) String 

func (rr *RR_TALINK) String() string

type RR_TKEY 

type RR_TKEY struct {
	Hdr        RR_Header
	Algorithm  string "domain-name"
	Inception  uint32
	Expiration uint32
	Mode       uint16
	Error      uint16
	KeySize    uint16
	Key        string
	Otherlen   uint16
	OtherData  string
}

func (*RR_TKEY) Header 

func (rr *RR_TKEY) Header() *RR_Header

func (*RR_TKEY) Len 

func (rr *RR_TKEY) Len() int

func (*RR_TKEY) String 

func (rr *RR_TKEY) String() string

type RR_TLSA 

type RR_TLSA struct {
	Hdr          RR_Header
	Usage        uint8
	Selector     uint8
	MatchingType uint8
	Certificate  string "hex"
}

DANE

func (*RR_TLSA) Header 

func (rr *RR_TLSA) Header() *RR_Header

func (*RR_TLSA) Len 

func (rr *RR_TLSA) Len() int

func (*RR_TLSA) String 

func (rr *RR_TLSA) String() string

type RR_TSIG 

type RR_TSIG struct {
	Hdr        RR_Header
	Algorithm  string "domain-name"
	TimeSigned uint64
	Fudge      uint16
	MACSize    uint16
	MAC        string "size-hex"
	OrigId     uint16
	Error      uint16
	OtherLen   uint16
	OtherData  string "size-hex"
}

RFC 2845.

func (*RR_TSIG) Header 

func (rr *RR_TSIG) Header() *RR_Header

func (*RR_TSIG) Len 

func (rr *RR_TSIG) Len() int

func (*RR_TSIG) String 

func (rr *RR_TSIG) String() string

TSIG has no official presentation format, but this will suffice.

type RR_TXT 

type RR_TXT struct {
	Hdr RR_Header
	Txt string "txt"
}

func (*RR_TXT) Header 

func (rr *RR_TXT) Header() *RR_Header

func (*RR_TXT) Len 

func (rr *RR_TXT) Len() int

func (*RR_TXT) String 

func (rr *RR_TXT) String() string

type RR_URI 

type RR_URI struct {
	Hdr      RR_Header
	Priority uint16
	Weight   uint16
	Target   string
}

func (*RR_URI) Header 

func (rr *RR_URI) Header() *RR_Header

func (*RR_URI) Len 

func (rr *RR_URI) Len() int

func (*RR_URI) String 

func (rr *RR_URI) String() string

type RRset 

type RRset []RR

An RRset is a slice of RRs.

func NewRRset 

func NewRRset() RRset

func (RRset) Ok 

func (s RRset) Ok() bool

Ok checks if the RRSet is RFC 2181 compliant.

func (*RRset) Pop 

func (s *RRset) Pop() RR

Pop removes the last pushed RR from the RRset. Returns nil when there is nothing to remove.

func (*RRset) Push 

func (s *RRset) Push(r RR) bool

Push pushes the RR r to the RRset.

func (RRset) String 

func (s RRset) String() string

type Request 

type Request struct {
	Request *Msg
	Addr    string
	Client  *Client
}

A Request is a incoming message from a Client

type RequestWriter 

type RequestWriter interface {
	Write(*Msg)
	Send(*Msg) error
	Receive() (*Msg, error)
	Close() error
	Dial() error
}

The RequestWriter interface is used by a DNS query handler to construct a DNS request.

type ResponseWriter 

type ResponseWriter interface {
	// RemoteAddr returns the net.Addr of the client that sent the current request.
	RemoteAddr() net.Addr
	// Write a reply back to the client.
	Write([]byte) (int, error)
}

A ResponseWriter interface is used by an DNS handler to construct an DNS response.

type ServeMux 

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

ServeMux is an DNS request multiplexer. It matches the zone name of each incoming request against a list of registered patterns add calls the handler for the pattern that most closely matches the zone name.

func NewServeMux 

func NewServeMux() *ServeMux

NewServeMux allocates and returns a new ServeMux.

func (*ServeMux) Handle 

func (mux *ServeMux) Handle(pattern string, handler Handler)

func (*ServeMux) HandleFunc 

func (mux *ServeMux) HandleFunc(pattern string, handler func(ResponseWriter, *Msg))

func (*ServeMux) ServeDNS 

func (mux *ServeMux) ServeDNS(w ResponseWriter, request *Msg)

ServeDNS dispatches the request to the handler whose pattern most closely matches the request message.

type Server 

type Server struct {
	Addr         string            // address to listen on, ":dns" if empty
	Net          string            // if "tcp" it will invoke a TCP listener, otherwise an UDP one
	Handler      Handler           // handler to invoke, dns.DefaultServeMux if nil
	UDPSize      int               // default buffer to use to read incoming UDP messages
	ReadTimeout  time.Duration     // the net.Conn.SetReadTimeout value for new connections
	WriteTimeout time.Duration     // the net.Conn.SetWriteTimeout value for new connections
	TsigSecret   map[string]string // secret(s) for Tsig map[<zonename>]<base64 secret>
}

A Server defines parameters for running an DNS server. Note how much it starts to look like 'Client struct'

func (*Server) ListenAndServe 

func (srv *Server) ListenAndServe() error

ListenAndServe starts a nameserver on the configured address.

func (*Server) ServeTCP 

func (srv *Server) ServeTCP(l *net.TCPListener) error

func (*Server) ServeUDP 

func (srv *Server) ServeUDP(l *net.UDPConn) error

type Token 

type Token struct {
	RR                // the scanned resource record
	Error *ParseError // when an error occured, this is the specifics
}

Source Files

View all Source files

Directories

Path Synopsis
examples
axfr
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