Network.DNS.Types

Data types for DNS Query and Response. For more information, see http://www.ietf.org/rfc/rfc1035.

Resource Records

data ResourceRecord

Raw data format for resource records.

Constructors

ResourceRecord

Fields

• rrname :: !Domain

  Name

• rrtype :: !TYPE

  Resource record type

• rrclass :: !CLASS

  Resource record class

• rrttl :: !TTL

  Time to live

• rdata :: !RData

  Resource data

Instances

Show ResourceRecord

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> ResourceRecord -> ShowS

show :: ResourceRecord -> String

showList :: [ResourceRecord] -> ShowS

Eq ResourceRecord

Defined in Network.DNS.Types.Internal

Methods

(==) :: ResourceRecord -> ResourceRecord -> Bool

(/=) :: ResourceRecord -> ResourceRecord -> Bool

type Answers = [ResourceRecord]

Type alias for resource records in the answer section.

type AuthorityRecords = [ResourceRecord]

Type alias for resource records in the answer section.

type AdditionalRecords = [ResourceRecord]

Type for resource records in the additional section.

Types

type Domain = ByteString

This type holds the presentation form of fully-qualified DNS domain names encoded as ASCII A-labels, with '.' separators between labels. Non-printing characters are escaped as \DDD (a backslash, followed by three decimal digits). The special characters: ", $, (, ), ;, @, and \ are escaped by prepending a backslash. The trailing '.' is optional on input, but is recommended, and is always added when decoding from wire form.

The encoding of domain names to wire form, e.g. for transmission in a query, requires the input encodings to be valid, otherwise a DecodeError may be thrown. Domain names received in wire form in DNS messages are escaped to this presentation form as part of decoding the DNSMessage.

This form is ASCII-only. Any conversion between A-label ByteStrings, and U-label Text happens at whatever layer maps user input to DNS names, or presents friendly DNS names to the user. Not all users can read all scripts, and applications that default to U-label form should ideally give the user a choice to see the A-label form. Examples:

www.example.org.           -- Ordinary DNS name.
_25._tcp.mx1.example.net.  -- TLSA RR initial labels have _ prefixes.
\001.exotic.example.       -- First label is Ctrl-A!
just\.one\.label.example.  -- First label is "just.one.label"

type CLASS = Word16

Resource record class.

classIN :: CLASS

Resource record class for the Internet.

type TTL = Word32

Time to live in second.

Resource Record Types

data TYPE where

Types for resource records.

Bundled Patterns

pattern A :: TYPE

IPv4 address

pattern NS :: TYPE

An authoritative name serve

pattern CNAME :: TYPE

The canonical name for an alias

pattern SOA :: TYPE

Marks the start of a zone of authority

pattern NULL :: TYPE

A null RR (EXPERIMENTAL)

pattern PTR :: TYPE

A domain name pointer

pattern MX :: TYPE

Mail exchange

pattern TXT :: TYPE

Text strings

pattern AAAA :: TYPE

IPv6 Address

pattern SRV :: TYPE

Server Selection (RFC2782)

pattern DNAME :: TYPE

DNAME (RFC6672)

pattern OPT :: TYPE

OPT (RFC6891)

pattern DS :: TYPE

Delegation Signer (RFC4034)

pattern RRSIG :: TYPE

RRSIG (RFC4034)

pattern NSEC :: TYPE

NSEC (RFC4034)

pattern DNSKEY :: TYPE

DNSKEY (RFC4034)

pattern NSEC3 :: TYPE

NSEC3 (RFC5155)

pattern NSEC3PARAM :: TYPE

NSEC3PARAM (RFC5155)

pattern TLSA :: TYPE

TLSA (RFC6698)

pattern CDS :: TYPE

Child DS (RFC7344)

pattern CDNSKEY :: TYPE

DNSKEY(s) the Child wants reflected in DS (RFC7344)

pattern CSYNC :: TYPE

Child-To-Parent Synchronization (RFC7477)

pattern AXFR :: TYPE

Zone transfer (RFC5936)

pattern ANY :: TYPE

A request for all records the server/cache has available

pattern CAA :: TYPE

Certification Authority Authorization (RFC6844)

Instances

Show TYPE

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> TYPE -> ShowS

show :: TYPE -> String

showList :: [TYPE] -> ShowS

Eq TYPE

Defined in Network.DNS.Types.Internal

Methods

(==) :: TYPE -> TYPE -> Bool

(/=) :: TYPE -> TYPE -> Bool

Ord TYPE

Defined in Network.DNS.Types.Internal

Methods

compare :: TYPE -> TYPE -> Ordering

(<) :: TYPE -> TYPE -> Bool

(<=) :: TYPE -> TYPE -> Bool

(>) :: TYPE -> TYPE -> Bool

(>=) :: TYPE -> TYPE -> Bool

max :: TYPE -> TYPE -> TYPE

min :: TYPE -> TYPE -> TYPE

fromTYPE :: TYPE -> Word16

From type to number.

toTYPE :: Word16 -> TYPE

From number to type.

Resource Data

data RData

Raw data format for each type.

Constructors

RD_A IPv4

IPv4 address

RD_NS Domain

An authoritative name serve

RD_CNAME Domain

The canonical name for an alias

RD_SOA Domain Mailbox Word32 Word32 Word32 Word32 Word32

Marks the start of a zone of authority

RD_NULL ByteString

NULL RR (EXPERIMENTAL, RFC1035).

RD_PTR Domain

A domain name pointer

RD_MX Word16 Domain

Mail exchange

RD_TXT ByteString

Text strings

RD_RP Mailbox Domain

Responsible Person (RFC1183)

RD_AAAA IPv6

IPv6 Address

RD_SRV Word16 Word16 Word16 Domain

Server Selection (RFC2782)

RD_DNAME Domain

DNAME (RFC6672)

RD_OPT [OData]

OPT (RFC6891)

RD_DS Word16 Word8 Word8 ByteString

Delegation Signer (RFC4034)

RD_RRSIG RD_RRSIG

DNSSEC signature

RD_NSEC Domain [TYPE]

DNSSEC denial of existence NSEC record

RD_DNSKEY Word16 Word8 Word8 ByteString

DNSKEY (RFC4034)

RD_NSEC3 Word8 Word8 Word16 ByteString ByteString [TYPE]

DNSSEC hashed denial of existence (RFC5155)

RD_NSEC3PARAM Word8 Word8 Word16 ByteString

NSEC3 zone parameters (RFC5155)

RD_TLSA Word8 Word8 Word8 ByteString

TLSA (RFC6698)

RD_CDS Word16 Word8 Word8 ByteString

Child DS (RFC7344)

RD_CDNSKEY Word16 Word8 Word8 ByteString

Child DNSKEY (RFC7344)

RD_CAA Word8 (CI ByteString) ByteString

CAA (RFC 6844) RD_CSYNC

UnknownRData ByteString

Unknown resource data

Instances

Show RData

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> RData -> ShowS

show :: RData -> String

showList :: [RData] -> ShowS

Eq RData

Defined in Network.DNS.Types.Internal

Methods

(==) :: RData -> RData -> Bool

(/=) :: RData -> RData -> Bool

Ord RData

Defined in Network.DNS.Types.Internal

Methods

compare :: RData -> RData -> Ordering

(<) :: RData -> RData -> Bool

(<=) :: RData -> RData -> Bool

(>) :: RData -> RData -> Bool

(>=) :: RData -> RData -> Bool

max :: RData -> RData -> RData

min :: RData -> RData -> RData

data RD_RRSIG

RRSIG representation.

As noted in Section 3.1.5 of RFC 4034 the RRsig inception and expiration times use serial number arithmetic. As a result these timestamps are not pure values, their meaning is time-dependent! They depend on the present time and are both at most approximately +/-68 years from the present. This ambiguity is not a problem because cached RRSIG records should only persist a few days, signature lifetimes should be *much* shorter than 68 years, and key rotation should result any misconstrued 136-year-old signatures fail to validate. This also means that the interpretation of a time that is exactly half-way around the clock at now +/-0x80000000 is not important, the signature should never be valid.

The upshot for us is that we need to convert these *impure* relative values to pure absolute values at the moment they are received from from the network (or read from files, ... in some impure I/O context), and convert them back to 32-bit values when encoding. Therefore, the constructor takes absolute 64-bit representations of the inception and expiration times.

The dnsTime function performs the requisite conversion.

Constructors

RDREP_RRSIG

Fields

• rrsigType :: !TYPE

  RRtype of RRset signed

• rrsigKeyAlg :: !Word8

  DNSKEY algorithm

• rrsigNumLabels :: !Word8

  Number of labels signed

• rrsigTTL :: !Word32

  Maximum origin TTL

• rrsigExpiration :: !Int64

  Time last valid

• rrsigInception :: !Int64

  Time first valid

• rrsigKeyTag :: !Word16

  Signing key tag

• rrsigZone :: !Domain

  Signing domain

• rrsigValue :: !ByteString

  Opaque signature

Instances

Show RD_RRSIG

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> RD_RRSIG -> ShowS

show :: RD_RRSIG -> String

showList :: [RD_RRSIG] -> ShowS

Eq RD_RRSIG

Defined in Network.DNS.Types.Internal

Methods

(==) :: RD_RRSIG -> RD_RRSIG -> Bool

(/=) :: RD_RRSIG -> RD_RRSIG -> Bool

Ord RD_RRSIG

Defined in Network.DNS.Types.Internal

Methods

compare :: RD_RRSIG -> RD_RRSIG -> Ordering

(<) :: RD_RRSIG -> RD_RRSIG -> Bool

(<=) :: RD_RRSIG -> RD_RRSIG -> Bool

(>) :: RD_RRSIG -> RD_RRSIG -> Bool

(>=) :: RD_RRSIG -> RD_RRSIG -> Bool

max :: RD_RRSIG -> RD_RRSIG -> RD_RRSIG

min :: RD_RRSIG -> RD_RRSIG -> RD_RRSIG

dnsTime

Arguments

:: Word32

DNS circle-arithmetic timestamp

-> Int64

current epoch time

-> Int64

absolute DNS timestamp

Given a 32-bit circle-arithmetic DNS time, and the current absolute epoch time, return the epoch time corresponding to the DNS timestamp.

DNS Message

data DNSMessage

DNS message format for queries and replies.

Constructors

DNSMessage

Fields

• header :: !DNSHeader

  Header with extended RCODE

• ednsHeader :: EDNSheader

  EDNS pseudo-header

• question :: [Question]

  The question for the name server

• answer :: Answers

  RRs answering the question

• authority :: AuthorityRecords

  RRs pointing toward an authority

• additional :: AdditionalRecords

  RRs holding additional information

Instances

Show DNSMessage

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> DNSMessage -> ShowS

show :: DNSMessage -> String

showList :: [DNSMessage] -> ShowS

Eq DNSMessage

Defined in Network.DNS.Types.Internal

Methods

(==) :: DNSMessage -> DNSMessage -> Bool

(/=) :: DNSMessage -> DNSMessage -> Bool

Query

makeQuery

Arguments

:: Identifier

Crypto random request id

-> Question

Question name and type

-> QueryControls

Custom RD/AD/CD flags and EDNS settings

-> DNSMessage

Construct a complete query DNSMessage, by combining the defaultQuery template with the specified Identifier, and Question. The QueryControls can be mempty to leave all header and EDNS settings at their default values, or some combination of overrides. A default set of overrides can be enabled via the resolvQueryControls field of ResolvConf. Per-query overrides are possible by using loookupRawCtl.

makeEmptyQuery

Arguments

:: QueryControls

Flag and EDNS overrides

-> DNSMessage

A query template with QueryControls overrides applied, with just the Question and query Identifier remaining to be filled in.

defaultQuery :: DNSMessage

A DNSMessage template for queries with default settings for the message DNSHeader and EDNSheader. This is the initial query message state, before customization via QueryControls.

Query Controls

data QueryControls

Query controls form a Monoid, as with function composition, the left-most value has the last say. The Monoid is generated by two sets of combinators, one that controls query-related DNS header flags, and another that controls EDNS features.

The header flag controls are: rdFlag, adFlag and cdFlag.

The EDNS feature controls are: doFlag, ednsEnabled, ednsSetVersion, ednsSetUdpSize and ednsSetOptions. When EDNS is disabled, all the other EDNS-related controls have no effect.

Example: Disable DNSSEC checking on the server, and request signatures and NSEC records, perhaps for your own independent validation. The UDP buffer size is set large, for use with a local loopback nameserver on the same host.

>>> :{
mconcat [ adFlag FlagClear
        , cdFlag FlagSet
        , doFlag FlagSet
        , ednsSetUdpSize (Just 8192) -- IPv4 loopback server?
        ]
:}
ad:0,cd:1,edns.udpsize:8192,edns.dobit:1

Example: Use EDNS version 1 (yet to be specified), request nameserver ids from the server, and indicate a client subnet of "192.0.2.1/24".

>>> :set -XOverloadedStrings
>>> let emptyNSID = ""
>>> let mask = 24
>>> let ipaddr = read "192.0.2.1"
>>> :{
mconcat [ ednsSetVersion (Just 1)
        , ednsSetOptions (ODataAdd [OD_NSID emptyNSID])
        , ednsSetOptions (ODataAdd [OD_ClientSubnet mask 0 ipaddr])
        ]
:}
edns.version:1,edns.options:[NSID,ClientSubnet]

Instances

Monoid QueryControls

Defined in Network.DNS.Types.Internal

Methods

mempty :: QueryControls

mappend :: QueryControls -> QueryControls -> QueryControls

mconcat :: [QueryControls] -> QueryControls

Semigroup QueryControls

Defined in Network.DNS.Types.Internal

Methods

(<>) :: QueryControls -> QueryControls -> QueryControls

sconcat :: NonEmpty QueryControls -> QueryControls

stimes :: Integral b => b -> QueryControls -> QueryControls

Show QueryControls

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> QueryControls -> ShowS

show :: QueryControls -> String

showList :: [QueryControls] -> ShowS

Eq QueryControls

Defined in Network.DNS.Types.Internal

Methods

(==) :: QueryControls -> QueryControls -> Bool

(/=) :: QueryControls -> QueryControls -> Bool

rdFlag :: FlagOp -> QueryControls

Generator of QueryControls that adjusts the RD bit.

>>> rdFlag FlagClear
rd:0

adFlag :: FlagOp -> QueryControls

Generator of QueryControls that adjusts the AD bit.

>>> adFlag FlagSet
ad:1

cdFlag :: FlagOp -> QueryControls

Generator of QueryControls that adjusts the CD bit.

>>> cdFlag FlagSet
cd:1

doFlag :: FlagOp -> QueryControls

Generator of QueryControls that adjusts the EDNS DnssecOk (DO) bit.

>>> doFlag FlagSet
edns.dobit:1

ednsEnabled :: FlagOp -> QueryControls

Generator of QueryControls that enables or disables EDNS support. When EDNS is disabled, the rest of the EDNS controls are ignored.

>>> ednsHeader $ makeEmptyQuery $ ednsEnabled FlagClear <> doFlag FlagSet
NoEDNS

ednsSetVersion :: Maybe Word8 -> QueryControls

Generator of QueryControls that adjusts the EDNS version. A value of Nothing makes no changes, while Just v sets the EDNS version to v.

>>> ednsSetVersion (Just 1)
edns.version:1

ednsSetUdpSize :: Maybe Word16 -> QueryControls

Generator of QueryControls that adjusts the EDNS UDP buffer size. A value of Nothing makes no changes, while Just n sets the EDNS UDP buffer size to n.

>>> ednsSetUdpSize (Just 2048)
edns.udpsize:2048

ednsSetOptions :: ODataOp -> QueryControls

Generator of QueryControls that adjusts the list of EDNS options.

>>> :set -XOverloadedStrings
>>> ednsSetOptions (ODataAdd [OD_NSID ""])
edns.options:[NSID]

Flag and OData control operations

data FlagOp

Boolean flag operations. These form a Monoid. When combined via mappend, as with function composition, the left-most value has the last say.

>>> mempty :: FlagOp
FlagKeep
>>> FlagSet <> mempty
FlagSet
>>> FlagClear <> FlagSet <> mempty
FlagClear
>>> FlagReset <> FlagClear <> FlagSet <> mempty
FlagReset

Constructors

FlagSet

Set the flag to 1

FlagClear

Clear the flag to 0

FlagReset

Reset the flag to its default value

FlagKeep

Leave the flag unchanged

Instances

Monoid FlagOp

Defined in Network.DNS.Types.Internal

Methods

mempty :: FlagOp

mappend :: FlagOp -> FlagOp -> FlagOp

mconcat :: [FlagOp] -> FlagOp

Semigroup FlagOp

Defined in Network.DNS.Types.Internal

Methods

(<>) :: FlagOp -> FlagOp -> FlagOp

sconcat :: NonEmpty FlagOp -> FlagOp

stimes :: Integral b => b -> FlagOp -> FlagOp

Show FlagOp

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> FlagOp -> ShowS

show :: FlagOp -> String

showList :: [FlagOp] -> ShowS

Eq FlagOp

Defined in Network.DNS.Types.Internal

Methods

(==) :: FlagOp -> FlagOp -> Bool

(/=) :: FlagOp -> FlagOp -> Bool

data ODataOp

The default EDNS Option list is empty. We define two operations, one to prepend a list of options, and another to set a specific list of options.

Constructors

ODataAdd [OData]

Add the specified options to the list.

ODataSet [OData]

Set the option list as specified.

Instances

Monoid ODataOp

Defined in Network.DNS.Types.Internal

Methods

mempty :: ODataOp

mappend :: ODataOp -> ODataOp -> ODataOp

mconcat :: [ODataOp] -> ODataOp

Semigroup ODataOp

Defined in Network.DNS.Types.Internal

Methods

(<>) :: ODataOp -> ODataOp -> ODataOp

sconcat :: NonEmpty ODataOp -> ODataOp

stimes :: Integral b => b -> ODataOp -> ODataOp

Eq ODataOp

Defined in Network.DNS.Types.Internal

Methods

(==) :: ODataOp -> ODataOp -> Bool

(/=) :: ODataOp -> ODataOp -> Bool

Response

defaultResponse :: DNSMessage

Default response. When responding to EDNS queries, the response must either be an EDNS response, or else FormatErr must be returned. The default response message has EDNS disabled (ednsHeader set to NoEDNS), it should be updated as appropriate.

Do not explicitly add OPT RRs to the additional section, instead let the encoder compute and add the OPT record based on the EDNS pseudo-header.

The RCODE in the DNSHeader should be set to the appropriate 12-bit extended value, which will be split between the primary header and EDNS OPT record during message encoding (low 4 bits in DNS header, high 8 bits in EDNS OPT record). See EDNSheader for more details.

makeResponse :: Identifier -> Question -> Answers -> DNSMessage

Construct a query response DNSMessage.

DNS Header

data DNSHeader

Raw data format for the header of DNS Query and Response.

Constructors

DNSHeader

Fields

• identifier :: !Identifier

  Query or reply identifier.

• flags :: !DNSFlags

  Flags, OPCODE, and RCODE

Instances

Show DNSHeader

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> DNSHeader -> ShowS

show :: DNSHeader -> String

showList :: [DNSHeader] -> ShowS

Eq DNSHeader

Defined in Network.DNS.Types.Internal

Methods

(==) :: DNSHeader -> DNSHeader -> Bool

(/=) :: DNSHeader -> DNSHeader -> Bool

type Identifier = Word16

An identifier assigned by the program that generates any kind of query.

DNS flags

data DNSFlags

Raw data format for the flags of DNS Query and Response.

Constructors

DNSFlags

Fields

• qOrR :: !QorR

  Query or response.

• opcode :: !OPCODE

  Kind of query.

• authAnswer :: !Bool

  AA (Authoritative Answer) bit - this bit is valid in responses, and specifies that the responding name server is an authority for the domain name in question section.

• trunCation :: !Bool

  TC (Truncated Response) bit - specifies that this message was truncated due to length greater than that permitted on the transmission channel.

• recDesired :: !Bool

  RD (Recursion Desired) bit - this bit may be set in a query and is copied into the response. If RD is set, it directs the name server to pursue the query recursively. Recursive query support is optional.

• recAvailable :: !Bool

  RA (Recursion Available) bit - this be is set or cleared in a response, and denotes whether recursive query support is available in the name server.

• rcode :: !RCODE

  The full 12-bit extended RCODE when EDNS is in use. Should always be zero in well-formed requests. When decoding replies, the high eight bits from any EDNS response are combined with the 4-bit RCODE from the DNS header. When encoding replies, if no EDNS OPT record is provided, RCODE values > 15 are mapped to FormatErr.

• authenData :: !Bool

  AD (Authenticated Data) bit - (RFC4035, Section 3.2.3).

• chkDisable :: !Bool

  CD (Checking Disabled) bit - (RFC4035, Section 3.2.2).

Instances

Show DNSFlags

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> DNSFlags -> ShowS

show :: DNSFlags -> String

showList :: [DNSFlags] -> ShowS

Eq DNSFlags

Defined in Network.DNS.Types.Internal

Methods

(==) :: DNSFlags -> DNSFlags -> Bool

(/=) :: DNSFlags -> DNSFlags -> Bool

data QorR

Query or response.

Constructors

QR_Query

Query.

QR_Response

Response.

Instances

Bounded QorR

Defined in Network.DNS.Types.Internal

Methods

minBound :: QorR

maxBound :: QorR

Enum QorR

Defined in Network.DNS.Types.Internal

Methods

succ :: QorR -> QorR

pred :: QorR -> QorR

toEnum :: Int -> QorR

fromEnum :: QorR -> Int

enumFrom :: QorR -> [QorR]

enumFromThen :: QorR -> QorR -> [QorR]

enumFromTo :: QorR -> QorR -> [QorR]

enumFromThenTo :: QorR -> QorR -> QorR -> [QorR]

Show QorR

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> QorR -> ShowS

show :: QorR -> String

showList :: [QorR] -> ShowS

Eq QorR

Defined in Network.DNS.Types.Internal

Methods

(==) :: QorR -> QorR -> Bool

(/=) :: QorR -> QorR -> Bool

defaultDNSFlags :: DNSFlags

Default DNSFlags record suitable for making recursive queries. By default the RD bit is set, and the AD and CD bits are cleared.

OPCODE and RCODE

data OPCODE

Kind of query.

Constructors

OP_STD

A standard query.

OP_INV

An inverse query (inverse queries are deprecated).

OP_SSR

A server status request.

OP_NOTIFY

A zone change notification (RFC1996)

OP_UPDATE

An update request (RFC2136)

Instances

Bounded OPCODE

Defined in Network.DNS.Types.Internal

Methods

minBound :: OPCODE

maxBound :: OPCODE

Enum OPCODE

Defined in Network.DNS.Types.Internal

Methods

succ :: OPCODE -> OPCODE

pred :: OPCODE -> OPCODE

toEnum :: Int -> OPCODE

fromEnum :: OPCODE -> Int

enumFrom :: OPCODE -> [OPCODE]

enumFromThen :: OPCODE -> OPCODE -> [OPCODE]

enumFromTo :: OPCODE -> OPCODE -> [OPCODE]

enumFromThenTo :: OPCODE -> OPCODE -> OPCODE -> [OPCODE]

Show OPCODE

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> OPCODE -> ShowS

show :: OPCODE -> String

showList :: [OPCODE] -> ShowS

Eq OPCODE

Defined in Network.DNS.Types.Internal

Methods

(==) :: OPCODE -> OPCODE -> Bool

(/=) :: OPCODE -> OPCODE -> Bool

fromOPCODE :: OPCODE -> Word16

Convert the internal representation of a DNS OPCODE to its 16-bit numeric value.

toOPCODE :: Word16 -> Maybe OPCODE

Convert a 16-bit DNS OPCODE number to its internal representation

data RCODE where

EDNS extended 12-bit response code. Non-EDNS messages use only the low 4 bits. With EDNS this stores the combined error code from the DNS header and and the EDNS psuedo-header. See EDNSheader for more detail.

Bundled Patterns

pattern NoErr :: RCODE

No error condition.

pattern FormatErr :: RCODE

Format error - The name server was unable to interpret the query.

pattern ServFail :: RCODE

Server failure - The name server was unable to process this query due to a problem with the name server.

pattern NameErr :: RCODE

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.

pattern NotImpl :: RCODE

Not Implemented - The name server does not support the requested kind of query.

pattern Refused :: RCODE

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.

pattern YXDomain :: RCODE

YXDomain - Dynamic update response, a pre-requisite domain that should not exist, does exist.

pattern YXRRSet :: RCODE

YXRRSet - Dynamic update response, a pre-requisite RRSet that should not exist, does exist.

pattern NXRRSet :: RCODE

NXRRSet - Dynamic update response, a pre-requisite RRSet that should exist, does not exist.

pattern NotAuth :: RCODE

NotAuth - Dynamic update response, the server is not authoritative for the zone named in the Zone Section.

pattern NotZone :: RCODE

NotZone - Dynamic update response, a name used in the Prerequisite or Update Section is not within the zone denoted by the Zone Section.

pattern BadVers :: RCODE

Bad OPT Version (BADVERS, RFC 6891).

pattern BadKey :: RCODE

Key not recognized [RFC2845]

pattern BadTime :: RCODE

Signature out of time window [RFC2845]

pattern BadMode :: RCODE

Bad TKEY Mode [RFC2930]

pattern BadName :: RCODE

Duplicate key name [RFC2930]

pattern BadAlg :: RCODE

Algorithm not supported [RFC2930]

pattern BadTrunc :: RCODE

Bad Truncation [RFC4635]

pattern BadCookie :: RCODE

Bad/missing Server Cookie [RFC7873]

pattern BadRCODE :: RCODE

Malformed (peer) EDNS message, no RCODE available. This is not an RCODE that can be sent by a peer. It lies outside the 12-bit range expressible via EDNS. The low 12-bits are chosen to coincide with FormatErr. When an EDNS message is malformed, and we're unable to extract the extended RCODE, the header rcode is set to BadRCODE.

Instances

Enum RCODE

Provide an Enum instance for backwards compatibility

Defined in Network.DNS.Types.Internal

Methods

succ :: RCODE -> RCODE

pred :: RCODE -> RCODE

toEnum :: Int -> RCODE

fromEnum :: RCODE -> Int

enumFrom :: RCODE -> [RCODE]

enumFromThen :: RCODE -> RCODE -> [RCODE]

enumFromTo :: RCODE -> RCODE -> [RCODE]

enumFromThenTo :: RCODE -> RCODE -> RCODE -> [RCODE]

Show RCODE

Use https://tools.ietf.org/html/rfc2929#section-2.3 names for DNS RCODEs

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> RCODE -> ShowS

show :: RCODE -> String

showList :: [RCODE] -> ShowS

Eq RCODE

Defined in Network.DNS.Types.Internal

Methods

(==) :: RCODE -> RCODE -> Bool

(/=) :: RCODE -> RCODE -> Bool

fromRCODE :: RCODE -> Word16

Convert an RCODE to its numeric value.

toRCODE :: Word16 -> RCODE

Convert a numeric value to a corresponding RCODE. The behaviour is undefined for values outside the range [0 .. 0xFFF] since the EDNS extended RCODE is a 12-bit value. Values in the range [0xF01 .. 0xFFF] are reserved for private use.

EDNS Pseudo-Header

data EDNSheader

Data type representing the optional EDNS pseudo-header of a DNSMessage When a single well-formed OPT ResourceRecord was present in the message's additional section, it is decoded to an EDNS record and and stored in the message ednsHeader field. The corresponding OPT RR is then removed from the additional section.

When the constructor is NoEDNS, no EDNS OPT record was present in the message additional section. When InvalidEDNS, the message holds either a malformed OPT record or more than one OPT record, which can still be found in (have not been removed from) the message additional section.

The EDNS OPT record augments the message error status with an 8-bit field that forms 12-bit extended RCODE when combined with the 4-bit RCODE from the unextended DNS header. In EDNS messages it is essential to not use just the bare 4-bit RCODE from the original DNS header. Therefore, in order to avoid potential misinterpretation of the response RCODE, when the OPT record is decoded, the upper eight bits of the error status are automatically combined with the rcode of the message header, so that there is only one place in which to find the full 12-bit result. Therefore, the decoded EDNS pseudo-header, does not hold any error status bits.

The reverse process occurs when encoding messages. The low four bits of the message header rcode are encoded into the wire-form DNS header, while the upper eight bits are encoded as part of the OPT record. In DNS responses with an rcode larger than 15, EDNS extensions SHOULD be enabled by providing a value for ednsHeader with a constructor of EDNSheader. If EDNS is not enabled in such a message, in order to avoid truncation of RCODE values that don't fit in the non-extended DNS header, the encoded wire-form RCODE is set to FormatErr.

When encoding messages for transmission, the ednsHeader is used to generate the additional OPT record. Do not add explicit OPT records to the aditional section, configure EDNS via the EDNSheader instead.

>>> let getopts eh = mapEDNS eh ednsOptions []
>>> let optsin     = [OD_ClientSubnet 24 0 $ read "192.0.2.1"]
>>> let masked     = [OD_ClientSubnet 24 0 $ read "192.0.2.0"]
>>> let message    = makeEmptyQuery $ ednsSetOptions $ ODataSet optsin
>>> let optsout    = getopts. ednsHeader <$> (decode $ encode message)
>>> optsout       == Right masked
True

Constructors

EDNSheader EDNS

A valid EDNS message

NoEDNS

A valid non-EDNS message

InvalidEDNS

Multiple or bad additional OPT RRs

Instances

Show EDNSheader

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> EDNSheader -> ShowS

show :: EDNSheader -> String

showList :: [EDNSheader] -> ShowS

Eq EDNSheader

Defined in Network.DNS.Types.Internal

Methods

(==) :: EDNSheader -> EDNSheader -> Bool

(/=) :: EDNSheader -> EDNSheader -> Bool

ifEDNS

Arguments

:: EDNSheader

EDNS pseudo-header

-> a

Value to return for EDNS messages

-> a

Value to return for non-EDNS messages

-> a

Return the second argument for EDNS messages, otherwise the third.

mapEDNS

Arguments

:: EDNSheader

EDNS pseudo-header

-> (EDNS -> a)

Function to apply to EDNS value

-> a

Default result for non-EDNS messages

-> a

Return the output of a function applied to the EDNS pseudo-header if EDNS is enabled, otherwise return a default value.

EDNS record

data EDNS

EDNS information defined in RFC 6891.

Constructors

EDNS

Fields

• ednsVersion :: !Word8

  EDNS version, presently only version 0 is defined.

• ednsUdpSize :: !Word16

  Supported UDP payload size.

• ednsDnssecOk :: !Bool

  Request DNSSEC replies (with RRSIG and NSEC records as as appropriate) from the server. Generally, not needed (except for diagnostic purposes) unless the signatures will be validated. Just setting the AD bit in the query and checking it in the response is sufficient (but often subject to man-in-the-middle forgery) if all that's wanted is whether the server validated the response.

• ednsOptions :: ![OData]

  EDNS options (e.g. OD_NSID, OD_ClientSubnet, ...)

Instances

Show EDNS

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> EDNS -> ShowS

show :: EDNS -> String

showList :: [EDNS] -> ShowS

Eq EDNS

Defined in Network.DNS.Types.Internal

Methods

(==) :: EDNS -> EDNS -> Bool

(/=) :: EDNS -> EDNS -> Bool

defaultEDNS :: EDNS

The default EDNS pseudo-header for queries. The UDP buffer size is set to 1216 bytes, which should result in replies that fit into the 1280 byte IPv6 minimum MTU. Since IPv6 only supports fragmentation at the source, and even then not all gateways forward IPv6 pre-fragmented IPv6 packets, it is best to keep DNS packet sizes below this limit when using IPv6 nameservers. A larger value may be practical when using IPv4 exclusively.

defaultEDNS = EDNS
    { ednsVersion = 0      -- The default EDNS version is 0
    , ednsUdpSize = 1232   -- IPv6-safe UDP MTU (RIPE recommendation)
    , ednsDnssecOk = False -- We don't do DNSSEC validation
    , ednsOptions = []     -- No EDNS options by default
    }

maxUdpSize :: Word16

Maximum UDP size that can be advertised. If the ednsUdpSize of EDNS is larger, then this value is sent instead. This value is likely to work only for local nameservers on the loopback network. Servers may enforce a smaller limit.

>>> maxUdpSize
16384

minUdpSize :: Word16

Minimum UDP size to advertise. If ednsUdpSize of EDNS is smaller, then this value is sent instead.

>>> minUdpSize
512

EDNS options

data OData

RData formats for a few EDNS options, and an opaque catchall

Constructors

OD_NSID ByteString

Name Server Identifier (RFC5001). Bidirectional, empty from client. (opaque octet-string). May contain binary data, which MUST be empty in queries.

OD_DAU [Word8]

DNSSEC Algorithm Understood (RFC6975). Client to server. (array of 8-bit numbers). Lists supported DNSKEY algorithms.

OD_DHU [Word8]

DS Hash Understood (RFC6975). Client to server. (array of 8-bit numbers). Lists supported DS hash algorithms.

OD_N3U [Word8]

NSEC3 Hash Understood (RFC6975). Client to server. (array of 8-bit numbers). Lists supported NSEC3 hash algorithms.

OD_ClientSubnet Word8 Word8 IP

Client subnet (RFC7871). Bidirectional. (source bits, scope bits, address). The address is masked and truncated when encoding queries. The address is zero-padded when decoding. Invalid input encodings result in an OD_ECSgeneric value instead.

OD_ECSgeneric Word16 Word8 Word8 ByteString

Unsupported or malformed IP client subnet option. Bidirectional. (address family, source bits, scope bits, opaque address).

UnknownOData Word16 ByteString

Generic EDNS option. (numeric OptCode, opaque content)

Instances

Show OData

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> OData -> ShowS

show :: OData -> String

showList :: [OData] -> ShowS

Eq OData

Defined in Network.DNS.Types.Internal

Methods

(==) :: OData -> OData -> Bool

(/=) :: OData -> OData -> Bool

Ord OData

Defined in Network.DNS.Types.Internal

Methods

compare :: OData -> OData -> Ordering

(<) :: OData -> OData -> Bool

(<=) :: OData -> OData -> Bool

(>) :: OData -> OData -> Bool

(>=) :: OData -> OData -> Bool

max :: OData -> OData -> OData

min :: OData -> OData -> OData

data OptCode where

EDNS Option Code (RFC 6891).

Bundled Patterns

pattern ClientSubnet :: OptCode

Client subnet (RFC7871)

pattern DAU :: OptCode

DNSSEC algorithm support (RFC6974, section 3)

pattern DHU :: OptCode

pattern N3U :: OptCode

pattern NSID :: OptCode

NSID (RFC5001, section 2.3)

Instances

Show OptCode

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> OptCode -> ShowS

show :: OptCode -> String

showList :: [OptCode] -> ShowS

Eq OptCode

Defined in Network.DNS.Types.Internal

Methods

(==) :: OptCode -> OptCode -> Bool

(/=) :: OptCode -> OptCode -> Bool

Ord OptCode

Defined in Network.DNS.Types.Internal

Methods

compare :: OptCode -> OptCode -> Ordering

(<) :: OptCode -> OptCode -> Bool

(<=) :: OptCode -> OptCode -> Bool

(>) :: OptCode -> OptCode -> Bool

(>=) :: OptCode -> OptCode -> Bool

max :: OptCode -> OptCode -> OptCode

min :: OptCode -> OptCode -> OptCode

fromOptCode :: OptCode -> Word16

From option code to number.

toOptCode :: Word16 -> OptCode

From number to option code.

DNS Body

data Question

Raw data format for DNS questions.

Constructors

Question

Fields

• qname :: Domain

  A domain name

• qtype :: TYPE

  The type of the query

Instances

Show Question

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> Question -> ShowS

show :: Question -> String

showList :: [Question] -> ShowS

Eq Question

Defined in Network.DNS.Types.Internal

Methods

(==) :: Question -> Question -> Bool

(/=) :: Question -> Question -> Bool

DNS Error

data DNSError

An enumeration of all possible DNS errors that can occur.

Constructors

SequenceNumberMismatch

The sequence number of the answer doesn't match our query. This could indicate foul play.

QuestionMismatch

The question section of the response doesn't match our query. This could indicate foul play.

InvalidAXFRLookup

A zone tranfer, i.e., a request of type AXFR, was attempted with the "lookup" interface. Zone transfer is different enough from "normal" requests that it requires a different interface.

RetryLimitExceeded

The number of retries for the request was exceeded.

TimeoutExpired

TCP fallback request timed out.

UnexpectedRDATA

The answer has the correct sequence number, but returned an unexpected RDATA format.

IllegalDomain

The domain for query is illegal.

FormatError

The name server was unable to interpret the query.

ServerFailure

The name server was unable to process this query due to a problem with the name server.

NameError

This code signifies that the domain name referenced in the query does not exist.

NotImplemented

The name server does not support the requested kind of query.

OperationRefused

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.

BadOptRecord

The server does not support the OPT RR version or content

BadConfiguration

Configuration is wrong.

NetworkFailure IOException

Network failure.

DecodeError String

Error is unknown

UnknownDNSError

Instances

Exception DNSError

Defined in Network.DNS.Types.Internal

Methods

toException :: DNSError -> SomeException

fromException :: SomeException -> Maybe DNSError

displayException :: DNSError -> String

Show DNSError

Defined in Network.DNS.Types.Internal

Methods

showsPrec :: Int -> DNSError -> ShowS

show :: DNSError -> String

showList :: [DNSError] -> ShowS

Eq DNSError

Defined in Network.DNS.Types.Internal

Methods

(==) :: DNSError -> DNSError -> Bool

(/=) :: DNSError -> DNSError -> Bool

Other types

type Mailbox = ByteString

Type for a mailbox encoded on the wire as a DNS name, but the first label is conceptually the local part of an email address, and may contain internal periods that are not label separators. Therefore, in mailboxes @ is used as the separator between the first and second labels, and any '.' characters in the first label are not escaped. The encoding is otherwise the same as Domain above. This is most commonly seen in the rname of SOA records, and is also employed in the mbox-dname field of RP records. On input, if there is no unescaped @ character in the Mailbox, it is reparsed with '.' as the first label separator. Thus the traditional format with all labels separated by dots is also accepted, but decoding from wire form always uses @ between the first label and the domain-part of the address. Examples:

[e-mail].  -- First label is simply hostmaster
[e-mail].   -- First label is john.smith