{-# LANGUAGE OverloadedStrings #-}
module FuncTorrent.Peer
(Peer(..),
- handShake
+ handlePeerMsgs
) where
-import Prelude hiding (lookup, concat, replicate, splitAt)
+import Prelude hiding (lookup, concat, replicate, splitAt, writeFile)
-import System.IO
-import Data.ByteString (ByteString, unpack, concat, hGet, hPut, singleton)
-import Data.ByteString.Char8 (replicate, pack)
+import System.IO (Handle, BufferMode(..), hSetBuffering)
+import Data.ByteString (ByteString, pack, unpack, concat, hGet, hPut, singleton, writeFile)
+import Data.ByteString.Lazy (fromStrict, fromChunks, toStrict)
+import qualified Data.ByteString.Char8 as BC (replicate, pack, length)
import Network (connectTo, PortID(..))
+import Data.Binary (Binary(..), decode, encode)
+import Data.Binary.Put (putWord32be, putWord16be, putWord8)
+import Data.Binary.Get (getWord32be, getWord16be, getWord8, runGet)
+import Control.Monad (replicateM, liftM, forM)
+import Control.Applicative ((<$>), liftA3)
+import Data.Bits
+import Data.Word (Word8)
+import Data.Map (Map, fromList, toList, (!), mapWithKey, adjust)
+
+import FuncTorrent.Metainfo (Info(..), Metainfo(..))
+import FuncTorrent.Utils (splitN, splitNum)
type ID = String
type IP = String
type Port = Integer
-data PeerState = PeerState { am_choking :: Bool
- , am_interested :: Bool
- , peer_choking :: Bool
- , peer_interested :: Bool }
+-- PeerState is a misnomer
+data PeerState = PeerState { handle :: Handle
+ , peer :: Peer
+ , meChoking :: Bool
+ , meInterested :: Bool
+ , heChoking :: Bool
+ , heInterested :: Bool}
+
+data PieceDlState = Pending
+ | InProgress
+ | Have
+ deriving (Show, Eq)
+
+-- todo - map with index to a new data structure (peers who have that piece amd state)
+data PieceData = PieceData { peers :: [Peer] -- ^ list of peers who have this piece
+ , state :: PieceDlState -- ^ state of the piece from download perspective.
+ , hash :: ByteString -- ^ piece hash
+ , len :: Integer } -- ^ piece length
+
+-- which piece is with which peers
+type PieceMap = Map Integer PieceData
-- | Peer is a PeerID, IP address, port tuple
data Peer = Peer ID IP Port
deriving (Show, Eq)
-data Msg = HandShakeMsg ByteString ID
- | KeepAliveMsg
- | ChokeMsg
- | UnChokeMsg
- | InterestedMsg
- | NotInterestedMsg
- | HaveMsg Integer
- | BitFieldMsg Integer
- | RequestMsg Integer Integer Integer
- | PieceMsg Integer Integer Integer
- | CancelMsg Integer Integer Integer
- | PortMsg Port
- deriving (Show)
+data PeerMsg = KeepAliveMsg
+ | ChokeMsg
+ | UnChokeMsg
+ | InterestedMsg
+ | NotInterestedMsg
+ | HaveMsg Integer
+ | BitFieldMsg ByteString
+ | RequestMsg Integer Integer Integer
+ | PieceMsg Integer Integer ByteString
+ | CancelMsg Integer Integer Integer
+ | PortMsg Port
+ deriving (Show)
+
+-- Make the initial Piece map, with the assumption that no peer has the
+-- piece and that every piece is pending download.
+mkPieceMap :: Integer -> ByteString -> [Integer] -> PieceMap
+mkPieceMap numPieces pieceHash pLengths = fromList kvs
+ where kvs = [(i, PieceData { peers = []
+ , state = Pending
+ , hash = h
+ , len = pLen })
+ | (i, h, pLen) <- zip3 [0..numPieces] hashes pLengths]
+ hashes = splitN (fromIntegral numPieces) pieceHash
+
+havePiece :: PieceMap -> Integer -> Bool
+havePiece pm index =
+ state (pm ! index) == Have
genHandShakeMsg :: ByteString -> String -> ByteString
genHandShakeMsg infoHash peer_id = concat [pstrlen, pstr, reserved, infoHash, peerID]
where pstrlen = singleton 19
- pstr = pack "BitTorrent protocol"
- reserved = replicate 8 '\0'
- peerID = pack peer_id
+ pstr = BC.pack "BitTorrent protocol"
+ reserved = BC.replicate 8 '\0'
+ peerID = BC.pack peer_id
-handShake :: Peer -> ByteString -> String -> IO ByteString
-handShake (Peer _ ip port) infoHash peerid = do
+handShake :: Peer -> ByteString -> String -> IO Handle
+handShake peer@(Peer _ ip port) infoHash peerid = do
let hs = genHandShakeMsg infoHash peerid
- handle <- connectTo ip (PortNumber (fromIntegral port))
- hSetBuffering handle LineBuffering
- hPut handle hs
- rlenBS <- hGet handle 1
- let rlen = fromIntegral $ (unpack rlenBS) !! 0
- hGet handle rlen
-
--- sendMsg :: Peer -> Handle -> PeerMsg -> IO ()
+ h <- connectTo ip (PortNumber (fromIntegral port))
+ hSetBuffering h LineBuffering
+ hPut h hs
+ putStrLn $ "--> handhake to peer: " ++ show peer
+ _ <- hGet h (length (unpack hs))
+ putStrLn $ "<-- handshake from peer: " ++ show peer
+ return h
+
+instance Binary PeerMsg where
+ put msg = case msg of
+ KeepAliveMsg -> putWord32be 0
+ ChokeMsg -> do putWord32be 1
+ putWord8 0
+ UnChokeMsg -> do putWord32be 1
+ putWord8 1
+ InterestedMsg -> do putWord32be 1
+ putWord8 2
+ NotInterestedMsg -> do putWord32be 1
+ putWord8 3
+ HaveMsg i -> do putWord32be 5
+ putWord8 4
+ putWord32be (fromIntegral i)
+ BitFieldMsg bf -> do putWord32be $ fromIntegral (1 + bfListLen)
+ putWord8 5
+ mapM_ putWord8 bfList
+ where bfList = unpack bf
+ bfListLen = length bfList
+ RequestMsg i o l -> do putWord32be 13
+ putWord8 6
+ putWord32be (fromIntegral i)
+ putWord32be (fromIntegral o)
+ putWord32be (fromIntegral l)
+ PieceMsg i o b -> do putWord32be $ fromIntegral (9 + blocklen)
+ putWord8 7
+ putWord32be (fromIntegral i)
+ putWord32be (fromIntegral o)
+ mapM_ putWord8 blockList
+ where blockList = unpack b
+ blocklen = length blockList
+ CancelMsg i o l -> do putWord32be 13
+ putWord8 8
+ putWord32be (fromIntegral i)
+ putWord32be (fromIntegral o)
+ putWord32be (fromIntegral l)
+ PortMsg p -> do putWord32be 3
+ putWord8 9
+ putWord16be (fromIntegral p)
+ get = do
+ l <- getWord32be
+ msgid <- getWord8
+ case msgid of
+ 0 -> return ChokeMsg
+ 1 -> return UnChokeMsg
+ 2 -> return InterestedMsg
+ 3 -> return NotInterestedMsg
+ 4 -> liftM (HaveMsg . fromIntegral) getWord32be
+ 5 -> liftM (BitFieldMsg . pack) (replicateM (fromIntegral l - 1) getWord8)
+ 6 -> liftA3 RequestMsg getInteger getInteger getInteger
+ where getInteger = fromIntegral <$> getWord32be
+ 7 -> liftA3 PieceMsg getInteger getInteger (pack <$> replicateM (fromIntegral l - 9) getWord8)
+ where getInteger = fromIntegral <$> getWord32be
+ 8 -> liftA3 CancelMsg getInteger getInteger getInteger
+ where getInteger = fromIntegral <$> getWord32be
+ 9 -> liftM (PortMsg . fromIntegral) getWord16be
+ _ -> error ("unknown message ID: " ++ show msgid)
+
+getMsg :: Handle -> IO PeerMsg
+getMsg h = do
+ lBS <- hGet h 4
+ let l = bsToInt lBS
+ if l == 0
+ then return KeepAliveMsg
+ else do
+ msg <- hGet h l
+ return $ decode $ fromStrict $ concat [lBS, msg]
+
+sendMsg :: Handle -> PeerMsg -> IO ()
+sendMsg h msg =
+ let bsMsg = toStrict $ encode msg
+ in
+ hPut h bsMsg
+
+bsToInt :: ByteString -> Int
+bsToInt x = fromIntegral (runGet getWord32be (fromChunks (return x)))
+
+bitfieldToList :: [Word8] -> [Integer]
+bitfieldToList bs = go bs 0
+ where go [] _ = []
+ go (b:bs') pos =
+ let setBits = [pos*8 + toInteger i | i <- [0..8], testBit b i]
+ in
+ setBits ++ go bs' (pos + 1)
+
+createDummyFile :: FilePath -> Int -> IO ()
+createDummyFile path size =
+ writeFile path (BC.replicate size '\0')
+
+-- loop1 :: shake hands with all peers, find out the pieces they have, form PieceData.
-- recvMsg :: Peer -> Handle -> Msg
+msgLoop :: PeerState -> PieceMap -> IO ()
+msgLoop pState pieceStatus | meInterested pState == False &&
+ heChoking pState == True = do
+ -- if me NOT Interested and she is Choking, tell her that
+ -- I am interested.
+ let h = handle pState
+ sendMsg h InterestedMsg
+ putStrLn $ "--> InterestedMsg to peer: " ++ show (peer pState)
+ msgLoop (pState { meInterested = True }) pieceStatus
+ | meInterested pState == True &&
+ heChoking pState == False =
+ -- if me Interested and she not Choking, send her a request
+ -- for a piece.
+ case pickPiece pieceStatus of
+ Nothing -> putStrLn "Nothing to download"
+ Just workPiece -> do
+ let pLen = len (pieceStatus ! workPiece)
+ _ <- downloadPiece (handle pState) workPiece pLen
+ -- sendMsg (handle state) (RequestMsg workPiece 0 pLen)
+ -- putStrLn $ "--> RequestMsg for Piece " ++ (show workPiece) ++ "to peer: " ++ show (peer state) ++ " of length: " ++ show pLen
+ -- msg <- getMsg (handle state)
+ -- putStrLn $ "<-- " ++ show msg ++ "from peer: " ++ show (peer state)
+ msgLoop pState (adjust (\pieceData -> pieceData { state = Have }) workPiece pieceStatus)
+ | otherwise = do
+ msg <- getMsg (handle pState)
+ putStrLn $ "<-- " ++ show msg ++ "from peer: " ++ show (peer pState)
+ case msg of
+ KeepAliveMsg -> do
+ sendMsg (handle pState) KeepAliveMsg
+ putStrLn $ "--> " ++ "KeepAliveMsg to peer: " ++ show (peer pState)
+ msgLoop pState pieceStatus
+ BitFieldMsg bss -> do
+ let pieceList = bitfieldToList (unpack bss)
+ pieceStatus' = updatePieceAvailability pieceStatus (peer pState) pieceList
+ print pieceList
+ -- 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
+ msgLoop pState pieceStatus'
+ UnChokeMsg -> do
+ msgLoop (pState { heChoking = False }) pieceStatus
+ _ -> do
+ msgLoop pState pieceStatus
+
+-- simple algorithm to pick piece.
+-- pick the first piece from 0 that is not downloaded yet.
+pickPiece :: PieceMap -> Maybe Integer
+pickPiece m =
+ let pieceList = toList m
+ allPending = filter (\(_, v) -> state v == Pending) pieceList
+ in
+ case allPending of
+ [] -> Nothing
+ ((i, _):_) -> Just i
+
+updatePieceAvailability :: PieceMap -> Peer -> [Integer] -> PieceMap
+updatePieceAvailability pieceStatus p pieceList =
+ mapWithKey (\k pd -> if k `elem` pieceList
+ then (pd { peers = p : (peers pd) })
+ else pd) pieceStatus
+
+handlePeerMsgs :: Peer -> Metainfo -> String -> IO ()
+handlePeerMsgs p m peerId = do
+ h <- handShake p (infoHash m) peerId
+ let state = PeerState { handle = h
+ , peer = p
+ , heInterested = False
+ , heChoking = True
+ , meInterested = False
+ , meChoking = True }
+ pieceHash = pieces (info m)
+ numPieces = (toInteger . (`quot` 20) . BC.length) pieceHash
+ pLen = pieceLength (info m)
+ fileLen = lengthInBytes (info m)
+ pieceStatus = mkPieceMap numPieces pieceHash (splitNum fileLen pLen)
+ msgLoop state pieceStatus
+
+downloadPiece :: Handle -> Integer -> Integer -> IO [PeerMsg]
+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
+ -- putStrLn $ "--> RequestMsg for Piece " ++ (show workPiece) ++ "to peer: " ++ show (peer state) ++ " of length: " ++ show pLen
+ getMsg h)
projects / functorrent.git / blobdiff