9 import Control.Applicative ((<$>))
10 import Control.Monad (liftM)
11 import qualified Data.ByteString.Char8 as BS (
16 import Data.Char (toLower)
33 import Text.Read (readMaybe)
35 type LookupResult = (Domain, Maybe [Domain])
37 -- | Perform a query, but take the result from the authority section
38 -- of the response rather than the answer section. Code shamelessly
39 -- stolen from Network.DNS.lookup.
40 lookup_authority :: Resolver -> Domain -> TYPE -> IO (Maybe [RDATA])
41 lookup_authority rlv dom typ = (>>= toRDATA) <$> lookupRaw rlv dom typ
43 correct r = rrtype r == typ
44 listToMaybe [] = Nothing
45 listToMaybe xs = Just xs
46 toRDATA = listToMaybe . map rdata . filter correct . authority
48 -- | Like lookupNS, except we take the result from the authority
49 -- section of the response (as opposed to the answer section).
50 lookupNS_authority :: Resolver -> Domain -> IO (Maybe [Domain])
51 lookupNS_authority rlv dom = toNS <$> DNS.lookup_authority rlv dom NS
53 toNS = fmap (map unTag)
55 unTag _ = error "lookupNS_authority"
57 resolve_address :: String -> IO (Maybe IPv4)
60 Just _ -> return read_result
62 default_rs <- makeResolvSeed defaultResolvConf
63 withResolver default_rs $ \resolver -> do
64 result <- lookupA resolver (BS.pack s)
65 return $ case result of
69 read_result :: Maybe IPv4
70 read_result = readMaybe s
72 lookupMX' :: Resolver -> Domain -> IO LookupResult
73 lookupMX' resolver domain =
74 liftM (pair_em . drop_priority) $ lookupMX resolver domain
76 drop_priority :: Maybe [(Domain, Int)] -> Maybe [Domain]
77 drop_priority = fmap (map fst)
79 pair_em :: a -> (Domain, a)
82 -- This function keeps the domain matches with its NS records.
83 lookupNS' :: Resolver -> Domain -> IO LookupResult
84 lookupNS' resolver domain = do
85 answer_result <- lookupNS resolver domain
86 auth_result <- lookupNS_authority resolver domain
87 liftM pair_em $ return $ combine answer_result auth_result
89 pair_em :: a -> (Domain, a)
92 combine :: (Maybe [Domain]) -> (Maybe [Domain]) -> (Maybe [Domain])
93 combine Nothing Nothing = Nothing
94 combine m1 Nothing = m1
95 combine Nothing m2 = m2
96 combine (Just ds1) (Just ds2) = Just (ds1 ++ ds2)
98 -- | Normalize the given name by lowercasing and appending a trailing
99 -- dot (the root) if necessary.
100 normalize :: Domain -> Domain
101 normalize = normalize_case . normalize_root
104 normalize_root :: Domain -> Domain
106 | BS.last d == '.' = d
107 | otherwise = d `BS.append` trailing_dot
109 trailing_dot = BS.pack "."
112 normalize_case :: Domain -> Domain
113 normalize_case = BS.map toLower