module Network.DNS.Internal where
import Data.ByteString (ByteString)
import qualified Data.ByteString.Char8 as BS
import Data.Char
import Data.IP
import Data.Maybe
type Domain = ByteString
data TYPE = A | AAAA | NS | TXT | MX | CNAME | SOA | PTR | SRV
| UNKNOWN Int deriving (Eq, Show, Read)
rrDB :: [(TYPE, Int)]
rrDB = [
(A, 1)
, (NS, 2)
, (CNAME, 5)
, (SOA, 6)
, (PTR, 12)
, (MX, 15)
, (TXT, 16)
, (AAAA, 28)
, (SRV, 33)
]
rookup :: (Eq b) => b -> [(a,b)] -> Maybe a
rookup _ [] = Nothing
rookup key ((x,y):xys)
| key == y = Just x
| otherwise = rookup key xys
intToType :: Int -> TYPE
intToType n = fromMaybe (UNKNOWN n) $ rookup n rrDB
typeToInt :: TYPE -> Int
typeToInt (UNKNOWN x) = x
typeToInt t = fromMaybe 0 $ lookup t rrDB
toType :: String -> TYPE
toType = read . map toUpper
data DNSFormat = DNSFormat {
header :: DNSHeader
, question :: [Question]
, answer :: [ResourceRecord]
, authority :: [ResourceRecord]
, additional :: [ResourceRecord]
} deriving (Eq, Show)
data DNSHeader = DNSHeader {
identifier :: Int
, flags :: DNSFlags
, qdCount :: Int
, anCount :: Int
, nsCount :: Int
, arCount :: Int
} deriving (Eq, Show)
data DNSFlags = DNSFlags {
qOrR :: QorR
, opcode :: OPCODE
, authAnswer :: Bool
, trunCation :: Bool
, recDesired :: Bool
, recAvailable :: Bool
, rcode :: RCODE
} deriving (Eq, Show)
data QorR = QR_Query | QR_Response deriving (Eq, Show)
data OPCODE = OP_STD | OP_INV | OP_SSR deriving (Eq, Show, Enum)
data RCODE = NoErr | FormatErr | ServFail | NameErr | NotImpl | Refused deriving (Eq, Show, Enum)
data Question = Question {
qname :: Domain
, qtype :: TYPE
} deriving (Eq, Show)
makeQuestion :: Domain -> TYPE -> Question
makeQuestion = Question
data ResourceRecord = ResourceRecord {
rrname :: Domain
, rrtype :: TYPE
, rrttl :: Int
, rdlen :: Int
, rdata :: RDATA
} deriving (Eq, Show)
data RDATA = RD_NS Domain | RD_CNAME Domain | RD_MX Int Domain | RD_PTR Domain
| RD_SOA Domain Domain Int Int Int Int Int
| RD_A IPv4 | RD_AAAA IPv6 | RD_TXT ByteString
| RD_SRV Int Int Int Domain
| RD_OTH [Int] deriving (Eq)
instance Show RDATA where
show (RD_NS dom) = BS.unpack dom
show (RD_MX prf dom) = BS.unpack dom ++ " " ++ show prf
show (RD_CNAME dom) = BS.unpack dom
show (RD_A a) = show a
show (RD_AAAA aaaa) = show aaaa
show (RD_TXT txt) = BS.unpack txt
show (RD_SOA mn _ _ _ _ _ mi) = BS.unpack mn ++ " " ++ show mi
show (RD_PTR dom) = BS.unpack dom
show (RD_SRV pri wei prt dom) = show pri ++ " " ++ show wei ++ " " ++ show prt ++ BS.unpack dom
show (RD_OTH is) = show is
defaultQuery :: DNSFormat
defaultQuery = DNSFormat {
header = DNSHeader {
identifier = 0
, flags = DNSFlags {
qOrR = QR_Query
, opcode = OP_STD
, authAnswer = False
, trunCation = False
, recDesired = True
, recAvailable = False
, rcode = NoErr
}
, qdCount = 0
, anCount = 0
, nsCount = 0
, arCount = 0
}
, question = []
, answer = []
, authority = []
, additional = []
}
defaultResponse :: DNSFormat
defaultResponse =
let hd = header defaultQuery
flg = flags hd
in defaultQuery {
header = hd {
flags = flg {
qOrR = QR_Response
, authAnswer = True
, recAvailable = True
}
}
}
responseA :: Int -> Question -> IPv4 -> DNSFormat
responseA ident q ip =
let hd = header defaultResponse
dom = qname q
an = ResourceRecord dom A 300 4 (RD_A ip)
in defaultResponse {
header = hd { identifier=ident, qdCount = 1, anCount = 1 }
, question = [q]
, answer = [an]
}
responseAAAA :: Int -> Question -> IPv6 -> DNSFormat
responseAAAA ident q ip =
let hd = header defaultResponse
dom = qname q
an = ResourceRecord dom AAAA 300 16 (RD_AAAA ip)
in defaultResponse {
header = hd { identifier=ident, qdCount = 1, anCount = 1 }
, question = [q]
, answer = [an]
}