make encoder and decoder invertable, and tests to ensure that.

6 files changed, 155 insertions, 30 deletions

diff --git a/Network/DNS/Internal.hs b/Network/DNS/Internal.hs
index 8274afe..0368bd4 100644
--- a/Network/DNS/Internal.hs
+++ b/Network/DNS/Internal.hs
@@ -151,7 +151,15 @@ defaultQuery :: DNSFormat
 defaultQuery = DNSFormat {
     header = DNSHeader {
        identifier = 0
-     , flags = undefined
+     , flags = DNSFlags {
+           qOrR         = QR_Query
+         , opcode       = OP_STD
+         , authAnswer   = False
+         , trunCation   = False
+         , recDesired   = True
+         , recAvailable = False
+         , rcode        = NoErr
+         }
      , qdCount = 0
      , anCount = 0
      , nsCount = 0
@@ -162,3 +170,39 @@ defaultQuery = DNSFormat {
   , 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]
+      }
diff --git a/Network/DNS/Query.hs b/Network/DNS/Query.hs
index 30c7e24..0d164b4 100644
--- a/Network/DNS/Query.hs
+++ b/Network/DNS/Query.hs
@@ -1,19 +1,28 @@
-module Network.DNS.Query (composeQuery) where
+{-# LANGUAGE RecordWildCards #-}
+module Network.DNS.Query (composeQuery, composeDNSFormat) where
 
 import qualified Data.ByteString.Lazy.Char8 as BL (ByteString)
 import qualified Data.ByteString  as BS (unpack)
 import qualified Data.ByteString.Char8 as BS (length, split, null)
+import Blaze.ByteString.Builder.ByteString (writeByteString)
 import Network.DNS.StateBinary
 import Network.DNS.Internal
 import Data.Monoid
+import Control.Monad.State
+import Data.Bits
+import Data.Word
+import Data.IP
 
 (+++) :: Monoid a => a -> a -> a
 (+++) = mappend
 
 ----------------------------------------------------------------
 
+composeDNSFormat :: DNSFormat -> BL.ByteString
+composeDNSFormat fmt = runSPut (encodeDNSFormat fmt)
+
 composeQuery :: Int -> [Question] -> BL.ByteString
-composeQuery idt qs = runSPut (encodeQuery qry)
+composeQuery idt qs = composeDNSFormat qry
   where
     hdr = header defaultQuery
     qry = defaultQuery {
@@ -26,12 +35,18 @@ composeQuery idt qs = runSPut (encodeQuery qry)
 
 ----------------------------------------------------------------
 
-encodeQuery :: DNSFormat -> SPut
-encodeQuery fmt = encodeHeader hdr
-              +++ encodeQuestion qs
+encodeDNSFormat :: DNSFormat -> SPut
+encodeDNSFormat fmt = encodeHeader hdr
+                  +++ mconcat (map encodeQuestion qs)
+                  +++ mconcat (map encodeRR an)
+                  +++ mconcat (map encodeRR au)
+                  +++ mconcat (map encodeRR ad)
   where
     hdr = header fmt
     qs = question fmt
+    an = answer fmt
+    au = authority fmt
+    ad = additional fmt
 
 encodeHeader :: DNSHeader -> SPut
 encodeHeader hdr = encodeIdentifier (identifier hdr)
@@ -48,16 +63,69 @@ encodeHeader hdr = encodeIdentifier (identifier hdr)
     decodeArCount = putInt16
 
 encodeFlags :: DNSFlags -> SPut
-encodeFlags _ = put16 0x0100 -- xxx
-
-encodeQuestion :: [Question] -> SPut
-encodeQuestion qs = encodeDomain dom
-                +++ putInt16 (typeToInt typ)
-                +++ put16 1
+encodeFlags DNSFlags{..} = put16 word
   where
-    q = head qs
-    dom = qname q
-    typ = qtype q
+    word16 :: Enum a => a -> Word16
+    word16 = toEnum . fromEnum
+
+    set :: Word16 -> State Word16 ()
+    set byte = modify (.|. byte)
+
+    st :: State Word16 ()
+    st = sequence_
+              [ set (word16 rcode)
+              , when recAvailable        $ set (bit 7)
+              , when recDesired          $ set (bit 8)
+              , when trunCation          $ set (bit 9)
+              , when authAnswer          $ set (bit 10)
+              , set (word16 opcode `shiftL` 11)
+              , when (qOrR==QR_Response) $ set (bit 15)
+              ]
+
+    word = execState st 0
+
+encodeQuestion :: Question -> SPut
+encodeQuestion Question{..} =
+        encodeDomain qname
+    +++ putInt16 (typeToInt qtype)
+    +++ put16 1
+
+encodeRR :: ResourceRecord -> SPut
+encodeRR ResourceRecord{..} =
+    mconcat
+      [ encodeDomain rrname
+      , putInt16 (typeToInt rrtype)
+      , put16 1
+      , putInt32 rrttl
+      , putInt16 rdlen
+      , encodeRDATA rdata
+      ]
+
+encodeRDATA :: RDATA -> SPut
+encodeRDATA rd = case rd of
+    (RD_A ip)          -> mconcat $ map putInt8 (fromIPv4 ip)
+    (RD_AAAA ip)       -> mconcat $ map putInt16 (fromIPv6 ip)
+    (RD_NS dom)        -> encodeDomain dom
+    (RD_CNAME dom)     -> encodeDomain dom
+    (RD_PTR dom)       -> encodeDomain dom
+    (RD_MX prf dom)    -> mconcat [putInt16 prf, encodeDomain dom]
+    (RD_TXT txt)       -> writeByteString txt
+    (RD_OTH bytes)     -> mconcat $ map putInt8 bytes
+    (RD_SOA d1 d2 serial refresh retry expire min') -> mconcat $
+        [ encodeDomain d1
+        , encodeDomain d2
+        , putInt32 serial
+        , putInt32 refresh
+        , putInt32 retry
+        , putInt32 expire
+        , putInt32 min'
+        ]
+    (RD_SRV prio weight port dom) -> mconcat $
+        [ putInt16 prio
+        , putInt16 weight
+        , putInt16 port
+        , encodeDomain dom
+        ]
 
 ----------------------------------------------------------------
 
diff --git a/Network/DNS/Resolver.hs b/Network/DNS/Resolver.hs
index 5919088..b3182f6 100644
--- a/Network/DNS/Resolver.hs
+++ b/Network/DNS/Resolver.hs
@@ -21,7 +21,7 @@ module Network.DNS.Resolver (
   -- ** Intermediate data type for resolver
   , ResolvSeed, makeResolvSeed
   -- ** Type and function for resolver
-  , Resolver, withResolver
+  , Resolver(..), withResolver
   -- ** Looking up functions
   , lookup, lookupRaw
   ) where
@@ -128,7 +128,7 @@ makeAddrInfo addr = do
   argument. 'withResolver' should be passed to 'forkIO'.
 -}
 
-withResolver :: ResolvSeed -> (Resolver -> IO ()) -> IO ()
+withResolver :: ResolvSeed -> (Resolver -> IO a) -> IO a
 withResolver seed func = do
   let ai = addrInfo seed
   sock <- socket (addrFamily ai) (addrSocketType ai) (addrProtocol ai)
diff --git a/Network/DNS/Response.hs b/Network/DNS/Response.hs
index 36f6203..abcb8ba 100644
--- a/Network/DNS/Response.hs
+++ b/Network/DNS/Response.hs
@@ -1,6 +1,6 @@
 {-# LANGUAGE OverloadedStrings #-}
 
-module Network.DNS.Response (responseIter, parseResponse) where
+module Network.DNS.Response (responseIter, parseResponse, runDNSFormat, runDNSFormat_) where
 
 import Control.Applicative
 import Control.Monad
@@ -12,13 +12,21 @@ import Network.DNS.Internal
 import Network.DNS.StateBinary
 import Data.Enumerator (Enumerator, Iteratee, run_, ($$))
 import Data.ByteString (ByteString)
+import qualified Data.ByteString.Lazy as BL
 
-responseIter :: Iteratee ByteString IO (DNSFormat, PState)
-responseIter = runSGet decodeResponse
+runDNSFormat :: BL.ByteString -> Either String (DNSFormat, PState)
+runDNSFormat bs = runSGet decodeResponse bs
 
-parseResponse :: Enumerator ByteString IO (a,b)
-              -> Iteratee ByteString IO (a,b)
-              -> IO a
+runDNSFormat_ :: BL.ByteString -> Either String DNSFormat
+runDNSFormat_ bs = fst <$> runDNSFormat bs
+
+responseIter :: Monad m => Iteratee ByteString m (DNSFormat, PState)
+responseIter = iterSGet decodeResponse
+
+parseResponse :: (Functor m, Monad m)
+              => Enumerator ByteString m (a,b)
+              -> Iteratee ByteString m (a,b)
+              -> m a
 parseResponse enum iter = fst <$> run_ (enum $$ iter)
 
 ----------------------------------------------------------------
diff --git a/Network/DNS/StateBinary.hs b/Network/DNS/StateBinary.hs
index 05f8468..e44ee98 100644
--- a/Network/DNS/StateBinary.hs
+++ b/Network/DNS/StateBinary.hs
@@ -5,6 +5,7 @@ import Control.Applicative
 import Control.Monad.State
 import Data.Attoparsec
 import Data.Attoparsec.Enumerator
+import qualified Data.Attoparsec.Lazy as AL
 import Data.ByteString (ByteString)
 import qualified Data.ByteString as BS (unpack)
 import qualified Data.ByteString.Lazy as BL (ByteString)
@@ -114,8 +115,11 @@ getNByteString n = lift (take n) <* addPosition n
 initialState :: PState
 initialState = PState IM.empty 0
 
-runSGet :: SGet a -> Iteratee ByteString IO (a, PState)
-runSGet parser = iterParser (runStateT parser initialState)
+iterSGet :: Monad m => SGet a -> Iteratee ByteString m (a, PState)
+iterSGet parser = iterParser (runStateT parser initialState)
+
+runSGet :: SGet a -> BL.ByteString -> Either String (a, PState)
+runSGet parser bs = AL.eitherResult $ AL.parse (runStateT parser initialState) bs
 
 runSPut :: SPut -> BL.ByteString
 runSPut = toLazyByteString . fromWrite
diff --git a/Network/DNS/Types.hs b/Network/DNS/Types.hs
index 58832e0..ce27046 100644
--- a/Network/DNS/Types.hs
+++ b/Network/DNS/Types.hs
@@ -8,18 +8,19 @@ module Network.DNS.Types (
   -- * TYPE
   , TYPE (..), intToType, typeToInt, toType
   -- * DNS Format
-  , DNSFormat, header, question, answer, authority, additional
+  , DNSFormat (DNSFormat), header, question, answer, authority, additional
   -- * DNS Header
-  , DNSHeader, identifier, flags, qdCount, anCount, nsCount, arCount
+  , DNSHeader (DNSHeader), identifier, flags, qdCount, anCount, nsCount, arCount
   -- * DNS Flags
-  , DNSFlags, qOrR, opcode, authAnswer, trunCation, recDesired, recAvailable, rcode
+  , DNSFlags (DNSFlags), qOrR, opcode, authAnswer, trunCation, recDesired, recAvailable, rcode
   -- * DNS Body
   , QorR (..)
   , OPCODE (..)
   , RCODE (..)
-  , ResourceRecord, rrname, rrtype, rrttl, rdlen, rdata
-  , Question, qname, qtype, makeQuestion
+  , ResourceRecord (ResourceRecord), rrname, rrtype, rrttl, rdlen, rdata
+  , Question (Question), qname, qtype, makeQuestion
   , RDATA (..)
+  , responseA, responseAAAA
   ) where
 
 import Network.DNS.Internal