bugfix: Hash string needs to be split into 20 bytes

[functorrent.git] / src / FuncTorrent / Peer.hs

diff --git a/src/FuncTorrent/Peer.hs b/src/FuncTorrent/Peer.hs
index ae768a88fd765d2709268b55cfc8ee3af711cece..b193e43633a4c34ed246fc146a41316053057d61 100644 (file)
--- a/src/FuncTorrent/Peer.hs
+++ b/src/FuncTorrent/Peer.hs
@@ -4,10 +4,10 @@ module FuncTorrent.Peer
      handlePeerMsgs
     ) where
 
-import Prelude hiding (lookup, concat, replicate, splitAt, writeFile)
+import Prelude hiding (lookup, concat, replicate, splitAt, writeFile, take)
 
 import System.IO (Handle, BufferMode(..), IOMode(..), SeekMode(..), withFile, hSeek, hSetBuffering)
-import Data.ByteString (ByteString, pack, unpack, concat, hGet, hPut, singleton, writeFile)
+import Data.ByteString (ByteString, pack, unpack, concat, hGet, hPut, singleton, writeFile, take, empty)
 import Data.ByteString.Lazy (fromStrict, fromChunks, toStrict)
 import qualified Data.ByteString.Char8 as BC (replicate, pack, length)
 import Network (connectTo, PortID(..))
@@ -19,6 +19,7 @@ import Control.Applicative ((<$>), liftA3)
 import Data.Bits
 import Data.Word (Word8)
 import Data.Map (Map, fromList, toList, (!), mapWithKey, adjust)
+import qualified Crypto.Hash.SHA1 as SHA1 (hash)
 
 import FuncTorrent.Metainfo (Info(..), Metainfo(..))
 import FuncTorrent.Utils (splitN, splitNum)
@@ -75,7 +76,7 @@ mkPieceMap numPieces pieceHash pLengths = fromList kvs
                              , hash = h
                              , len = pLen })
               | (i, h, pLen) <- zip3 [0..numPieces] hashes pLengths]
-        hashes = splitN (fromIntegral numPieces) pieceHash
+        hashes = splitN 20 pieceHash
 
 havePiece :: PieceMap -> Integer -> Bool
 havePiece pm index =
@@ -191,9 +192,9 @@ createDummyFile path size =
 -- write into a file at a specific offet
 writeFileAtOffset :: FilePath -> Integer -> ByteString -> IO ()
 writeFileAtOffset path offset block =
-  withFile path WriteMode $ (\h -> do
-                                _ <- hSeek h AbsoluteSeek offset
-                                hPut h block)
+  withFile path ReadWriteMode $ (\h -> do
+                                 _ <- hSeek h AbsoluteSeek offset
+                                 hPut h block)
 
 -- recvMsg :: Peer -> Handle -> Msg
 msgLoop :: PeerState -> PieceMap -> IO ()
@@ -213,8 +214,12 @@ msgLoop pState pieceStatus | meInterested pState == False &&
                                Nothing -> putStrLn "Nothing to download"
                                Just workPiece -> do
                                  let pLen = len (pieceStatus ! workPiece)
-                                 _ <- downloadPiece (handle pState) workPiece pLen
-                                 -- TODO: verify the hash
+                                 pBS <- downloadPiece (handle pState) workPiece pLen
+                                 -- if not $ verifyHash pBS (hash (pieceStatus ! workPiece))
+                                 --  then
+                                 --  putStrLn $ "Hash mismatch: " ++ show (hash (pieceStatus ! workPiece)) ++ " vs " ++ show (take 20 (SHA1.hash pBS))
+                                 --  else do
+                                 writeFileAtOffset "/tmp/download.file" (workPiece * pLen) pBS
                                  msgLoop pState (adjust (\pieceData -> pieceData { state = Have }) workPiece pieceStatus)
                           | otherwise = do
                               msg <- getMsg (handle pState)
@@ -227,7 +232,7 @@ msgLoop pState pieceStatus | meInterested pState == False &&
                                BitFieldMsg bss -> do
                                  let pieceList = bitfieldToList (unpack bss)
                                      pieceStatus' = updatePieceAvailability pieceStatus (peer pState) pieceList
-                                 print pieceList
+                                 putStrLn $ show (length pieceList) ++ " Pieces"
                                  -- for each pieceIndex in pieceList, make an entry in the pieceStatus
                                  -- map with pieceIndex as the key and modify the value to add the peer.
                                  -- download each of the piece in order
@@ -268,19 +273,29 @@ handlePeerMsgs p m peerId = do
       pLen = pieceLength (info m)
       fileLen = lengthInBytes (info m)
       pieceStatus = mkPieceMap numPieces pieceHash (splitNum fileLen pLen)
+  createDummyFile "/tmp/download.file" (fromIntegral fileLen)
   msgLoop state pieceStatus
   
-downloadPiece :: Handle -> Integer -> Integer -> IO [ByteString]
+downloadPiece :: Handle -> Integer -> Integer -> IO ByteString
 downloadPiece h index pieceLength = do
   let chunks = splitNum pieceLength 16384
-  forM (zip [0..] chunks) (\(i, pLen) -> do
-                              sendMsg h (RequestMsg index (i*pLen) pLen)
-                              putStrLn $ "--> " ++ "RequestMsg for Piece "
-                                ++ (show index) ++ ", part: " ++ show i ++ " of length: "
-                                ++ show pLen
-                              PieceMsg index begin block <- getMsg h
-                              putStrLn $ " <-- PieceMsg for Piece: "
-                                ++ show index
-                                ++ ", offset: "
-                                ++ show begin
-                              return block)
+  liftM concat $ forM (zip [0..] chunks) (\(i, pLen) -> do
+                                             sendMsg h (RequestMsg index (i*pLen) pLen)
+                                             putStrLn $ "--> " ++ "RequestMsg for Piece "
+                                               ++ (show index) ++ ", part: " ++ show i ++ " of length: "
+                                               ++ show pLen
+                                             msg <- getMsg h
+                                             case msg of
+                                              PieceMsg index begin block -> do
+                                                putStrLn $ " <-- PieceMsg for Piece: "
+                                                  ++ show index
+                                                  ++ ", offset: "
+                                                  ++ show begin
+                                                return block
+                                              _ -> do
+                                                putStrLn "ignoring irrelevant msg"
+                                                return empty)
+
+verifyHash :: ByteString -> ByteString -> Bool
+verifyHash bs pieceHash =
+  take 20 (SHA1.hash bs) == pieceHash