{-# LANGUAGE OverloadedStrings #-}
module FuncTorrent.Peer
(Peer(..),
- handShake
+ handlePeerMsgs
) where
-import Prelude hiding (lookup, concat, replicate, splitAt)
+import Prelude hiding (lookup, concat, replicate, splitAt, take)
-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, unpack, concat, hGet, hPut, take, empty)
+import qualified Data.ByteString.Char8 as BC (length)
import Network (connectTo, PortID(..))
+import Control.Monad.State
+import Data.Bits
+import Data.Word (Word8)
+import Data.Map (Map, fromList, toList, (!), mapWithKey, adjust)
+import qualified Crypto.Hash.SHA1 as SHA1 (hash)
-type ID = String
-type IP = String
-type Port = Integer
-
-data PeerState = PeerState { am_choking :: Bool
- , am_interested :: Bool
- , peer_choking :: Bool
- , peer_interested :: Bool }
-
--- | 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)
-
-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
-
-handShake :: Peer -> ByteString -> String -> IO ByteString
-handShake (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 ()
--- recvMsg :: Peer -> Handle -> Msg
+import FuncTorrent.Metainfo (Info(..), Metainfo(..))
+import FuncTorrent.Utils (splitN, splitNum)
+import FuncTorrent.Fileops (createDummyFile, writeFileAtOffset)
+import FuncTorrent.PeerMsgs (Peer(..), PeerMsg(..), sendMsg, getMsg, genHandshakeMsg)
+
+data PState = PState { handle :: Handle
+ , peer :: Peer
+ , meChoking :: Bool
+ , meInterested :: Bool
+ , heChoking :: Bool
+ , heInterested :: Bool}
+
+type PeerState = State PState
+
+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
+ , dlstate :: 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
+
+
+-- 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 = []
+ , dlstate = Pending
+ , hash = h
+ , len = pLen })
+ | (i, h, pLen) <- zip3 [0..numPieces] hashes pLengths]
+ hashes = splitN 20 pieceHash
+
+havePiece :: PieceMap -> Integer -> Bool
+havePiece pm index =
+ dlstate (pm ! index) == Have
+
+connectToPeer :: Peer -> IO Handle
+connectToPeer (Peer _ ip port) = do
+ h <- connectTo ip (PortNumber (fromIntegral port))
+ hSetBuffering h LineBuffering
+ return h
+
+doHandshake :: Handle -> Peer -> ByteString -> String -> IO ()
+doHandshake h peer infoHash peerid = do
+ let hs = genHandshakeMsg infoHash peerid
+ hPut h hs
+ putStrLn $ "--> handhake to peer: " ++ show peer
+ _ <- hGet h (length (unpack hs))
+ putStrLn $ "<-- handshake from peer: " ++ show peer
+ return ()
+
+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)
+
+-- helper functions to manipulate PeerState
+toPeerState :: Handle
+ -> Peer
+ -> Bool -- ^ meChoking
+ -> Bool -- ^ meInterested
+ -> Bool -- ^ heChoking
+ -> Bool -- ^ heInterested
+ -> PState
+toPeerState h p meCh meIn heCh heIn =
+ PState { handle = h
+ , peer = p
+ , heChoking = heCh
+ , heInterested = heIn
+ , meChoking = meCh
+ , meInterested = meIn }
+
+-- 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) -> dlstate 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 <- connectToPeer p
+ doHandshake h p (infoHash m) peerId
+ let pstate = toPeerState h p False True False True
+ pieceHash = pieces (info m)
+ numPieces = (toInteger . (`quot` 20) . BC.length) pieceHash
+ pLen = pieceLength (info m)
+ fileLen = lengthInBytes (info m)
+ fileName = name (info m)
+ pieceStatus = mkPieceMap numPieces pieceHash (splitNum fileLen pLen)
+ createDummyFile fileName (fromIntegral fileLen)
+ (r, _) <- runStateT (msgLoop pieceStatus fileName) pstate
+ return ()
+
+msgLoop :: PieceMap -> FilePath -> StateT PState IO ()
+msgLoop pieceStatus file = do
+ h <- gets handle
+ st <- get
+ case st of
+ PState { meInterested = False, heChoking = True } -> do
+ liftIO $ sendMsg h InterestedMsg
+ gets peer >>= (\p -> liftIO $ putStrLn $ "--> InterestedMsg to peer: " ++ show p)
+ modify (\st -> st { meInterested = True })
+ msgLoop pieceStatus file
+ PState { meInterested = True, heChoking = False } -> do
+ case pickPiece pieceStatus of
+ Nothing -> liftIO $ putStrLn "Nothing to download"
+ Just workPiece -> do
+ let pLen = len (pieceStatus ! workPiece)
+ liftIO $ putStrLn $ "piece length = " ++ show pLen
+ pBS <- liftIO $ downloadPiece h workPiece pLen
+ if not $ verifyHash pBS (hash (pieceStatus ! workPiece))
+ then
+ liftIO $ putStrLn $ "Hash mismatch: " ++ show (hash (pieceStatus ! workPiece)) ++ " vs " ++ show (take 20 (SHA1.hash pBS))
+ else do
+ let fileOffset = if workPiece == 0 then 0 else workPiece * len (pieceStatus ! (workPiece - 1))
+ liftIO $ putStrLn $ "Write into file at offset: " ++ show fileOffset
+ liftIO $ writeFileAtOffset file fileOffset pBS
+ msgLoop (adjust (\pieceData -> pieceData { dlstate = Have }) workPiece pieceStatus) file
+ _ -> do
+ msg <- liftIO $ getMsg h
+ gets peer >>= (\p -> liftIO $ putStrLn $ "<-- " ++ show msg ++ "from peer: " ++ show p)
+ case msg of
+ KeepAliveMsg -> do
+ liftIO $ sendMsg h KeepAliveMsg
+ gets peer >>= (\p -> liftIO $ putStrLn $ "--> " ++ "KeepAliveMsg to peer: " ++ show p)
+ msgLoop pieceStatus file
+ BitFieldMsg bss -> do
+ p <- gets peer
+ let pieceList = bitfieldToList (unpack bss)
+ pieceStatus' = updatePieceAvailability pieceStatus p pieceList
+ liftIO $ 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
+ msgLoop pieceStatus' file
+ UnChokeMsg -> do
+ modify (\st -> st {heChoking = False })
+ msgLoop pieceStatus file
+
+
+downloadPiece :: Handle -> Integer -> Integer -> IO ByteString
+downloadPiece h index pieceLength = do
+ let chunks = splitNum pieceLength 16384
+ 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
projects / functorrent.git / blobdiff