From fa4220513eb9d2036c3db0cc9c518c6346050318 Mon Sep 17 00:00:00 2001
From: Michael Orlitzky <michael@orlitzky.com>
Date: Wed, 24 Jul 2013 21:12:29 -0400
Subject: [PATCH] Add MX support (untested).

---
 src/DNS.hs  | 29 ++++++++++++++++++++++++++++-
 src/Main.hs | 46 +++++++++++++++++++++++-----------------------
 2 files changed, 51 insertions(+), 24 deletions(-)

diff --git a/src/DNS.hs b/src/DNS.hs
index 08d4f21..5222cbe 100644
--- a/src/DNS.hs
+++ b/src/DNS.hs
@@ -1,4 +1,7 @@
 module DNS (
+  LookupResult,
+  lookupMX',
+  lookupNS',
   normalize
   )
 where
@@ -9,7 +12,31 @@ import qualified Data.ByteString.Char8 as BS (
   map,
   pack )
 import Data.Char (toLower)
-import Network.DNS.Types (Domain)
+import Network.DNS (
+  Domain,
+  Resolver,
+  lookupMX,
+  lookupNS )
+
+type LookupResult = (Domain, Maybe [Domain])
+
+lookupMX' :: Resolver -> Domain -> IO LookupResult
+lookupMX' resolver domain =
+  lookupMX resolver domain >>= return . pair_em . drop_priority
+  where
+    drop_priority :: Maybe [(Domain, Int)] -> Maybe [Domain]
+    drop_priority = fmap (map fst)
+
+    pair_em :: a -> (Domain, a)
+    pair_em = (,) domain
+
+-- This function keeps the domain matches with its NS records.
+lookupNS' :: Resolver -> Domain -> IO LookupResult
+lookupNS' resolver domain =
+  lookupNS resolver domain >>= return . pair_em
+  where
+    pair_em :: a -> (Domain, a)
+    pair_em = (,) domain
 
 -- | Normalize the given name by lowercasing and appending a trailing
 --   dot (the root) if necessary.
diff --git a/src/Main.hs b/src/Main.hs
index d425734..0c215b7 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -16,12 +16,15 @@ import Network.DNS (
   FileOrNumericHost(RCHostName),
   ResolvConf(resolvInfo),
   defaultResolvConf,
-  lookupNS,
   makeResolvSeed,
   withResolver )
 
 import CommandLine (Args(..), get_args)
-import DNS (normalize)
+import DNS (
+  LookupResult,
+  lookupMX',
+  lookupNS',
+  normalize )
 
 report :: (Domain, Maybe [Domain]) -> IO ()
 report (d, Nothing) =
@@ -35,11 +38,12 @@ report (d, Just leftovers) =
                   (join " " (map show leftovers))
 
 clean :: [Domain] -- ^ List of delegates, @ds@
-      -> (Domain, Maybe [Domain]) -- ^ Pairs of (domain name, lookup result)
-      -> (Domain, Maybe [Domain])
+      -> LookupResult
+      -> LookupResult
 clean _ p@(_, Nothing) = p
-clean ds (d, Just targets) =
-  (d, Just $ targets \\ ds)
+clean delgts (d, Just targets) =
+  (d, Just $ targets \\ delgts)
+
 
 
 main :: IO ()
@@ -64,20 +68,16 @@ main = do
              Just s -> defaultResolvConf { resolvInfo = RCHostName s }
 
   rs <- makeResolvSeed rc
-  withResolver rs $ \resolver -> do
-    -- This function keeps the domain matches with its NS records.
-    let lookupNS' = \d -> (lookupNS resolver d) >>= (return . ((,) d))
-
-    -- Bad stuff happens if we try to run these lookups in parallel
-    -- instead of the reports.
-    domains_ns <- mapM lookupNS' nrml_domains
-    let cdns = map (clean nrml_delegates) domains_ns
-
-    _ <- case cfg of
-           (NS _ _) ->
-             -- We're only checking NS records, so report what we found.
-             parallel (map report cdns)
-           (MX _ _) ->
-             return [()]
-
-    stopGlobalPool
+
+  let lookup_function = case cfg of
+                          (NS _ _) -> lookupNS'
+                          (MX _ _) -> lookupMX'
+
+  _ <- withResolver rs $ \resolver -> do
+         -- Bad stuff happens if we try to run these lookups in parallel
+         -- instead of the reports.
+         records <- mapM (lookup_function resolver) nrml_domains
+         let cleaned_records = map (clean nrml_delegates) records
+         parallel (map report cleaned_records)
+
+  stopGlobalPool
-- 
2.43.2