10 import Control.Applicative ((<$>))
11 import Control.Monad (liftM)
12 import qualified Data.ByteString.Char8 as BS (
17 import Data.Char (toLower)
34 import Text.Read (readMaybe)
36 type LookupResult = (Domain, Maybe [Domain])
38 -- | Perform a query, but take the result from the authority section
39 -- of the response rather than the answer section. Code shamelessly
40 -- stolen from Network.DNS.lookup.
41 lookup_authority :: Resolver -> Domain -> TYPE -> IO (Maybe [RDATA])
42 lookup_authority rlv dom typ = (>>= toRDATA) <$> lookupRaw rlv dom typ
44 correct r = rrtype r == typ
45 listToMaybe [] = Nothing
46 listToMaybe xs = Just xs
47 toRDATA = listToMaybe . map rdata . filter correct . authority
49 -- | Like lookupNS, except we take the result from the authority
50 -- section of the response (as opposed to the answer section).
51 lookupNS_authority :: Resolver -> Domain -> IO (Maybe [Domain])
52 lookupNS_authority rlv dom = toNS <$> DNS.lookup_authority rlv dom NS
54 toNS = fmap (map unTag)
56 unTag _ = error "lookupNS_authority"
58 resolve_address :: String -> IO (Maybe IPv4)
61 Just _ -> return read_result
63 default_rs <- makeResolvSeed defaultResolvConf
64 withResolver default_rs $ \resolver -> do
65 result <- lookupA resolver (BS.pack s)
66 return $ case result of
70 read_result :: Maybe IPv4
71 read_result = readMaybe s
73 lookupMX' :: Resolver -> Domain -> IO LookupResult
74 lookupMX' resolver domain =
75 liftM (pair_em . drop_priority) $ lookupMX resolver domain
77 drop_priority :: Maybe [(Domain, Int)] -> Maybe [Domain]
78 drop_priority = fmap (map fst)
80 pair_em :: a -> (Domain, a)
83 -- This function keeps the domain matches with its NS records.
84 lookupNS' :: Resolver -> Domain -> IO LookupResult
85 lookupNS' resolver domain = do
86 answer_result <- lookupNS resolver domain
87 auth_result <- lookupNS_authority resolver domain
88 liftM pair_em $ return $ combine answer_result auth_result
90 pair_em :: a -> (Domain, a)
93 combine :: (Maybe [Domain]) -> (Maybe [Domain]) -> (Maybe [Domain])
94 combine Nothing Nothing = Nothing
95 combine m1 Nothing = m1
96 combine Nothing m2 = m2
97 combine (Just ds1) (Just ds2) = Just (ds1 ++ ds2)
99 -- | Normalize the given name by lowercasing and appending a trailing
100 -- dot (the root) if necessary.
101 normalize :: Domain -> Domain
102 normalize = normalize_case . normalize_root
105 normalize_root :: Domain -> Domain
107 | BS.last d == '.' = d
108 | otherwise = d `BS.append` trailing_dot
110 trailing_dot = BS.pack "."
113 normalize_case :: Domain -> Domain
114 normalize_case = BS.map toLower