{-# LANGUAGE OverloadedStrings #-}
module FuncTorrent.Peer
(Peer(..),
- handShake,
- msgLoop
+ handlePeerMsgs
) where
-import Prelude hiding (lookup, concat, replicate, splitAt, empty)
+import Prelude hiding (lookup, concat, replicate, splitAt, take)
-import System.IO
-import Data.ByteString (ByteString, pack, unpack, concat, hGet, hPut, singleton)
-import Data.ByteString.Lazy (fromStrict, fromChunks)
+import System.IO (Handle, BufferMode(..), hSetBuffering)
+import Data.ByteString (ByteString, pack, unpack, concat, hGet, hPut, singleton, take, empty)
+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)
+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, forever)
+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 qualified Crypto.Hash.SHA1 as SHA1 (hash)
+
+import FuncTorrent.Metainfo (Info(..), Metainfo(..))
+import FuncTorrent.Utils (splitN, splitNum)
+import FuncTorrent.Fileops (createDummyFile, writeFileAtOffset)
type ID = String
type IP = String
type Port = Integer
+-- PeerState is a misnomer
data PeerState = PeerState { handle :: Handle
- , am_choking :: Bool
- , am_interested :: Bool
- , peer_choking :: Bool
- , peer_interested :: Bool}
+ , peer :: Peer
+ , meChoking :: Bool
+ , meInterested :: Bool
+ , heChoking :: Bool
+ , heInterested :: Bool}
--- Maintain info on every piece and the current state of it.
--- should probably be a TVar.
-type Pieces = [PieceData]
+data PieceDlState = Pending
+ | InProgress
+ | Have
+ deriving (Show, Eq)
-data PieceState = Pending
- | InProgress
- | Have
- deriving (Show)
+-- 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
-data PieceData = PieceData { index :: Int -- ^ Piece number
- , peers :: [Peer] -- ^ list of peers who have this piece
- , state :: PieceState } -- ^ state of the piece from download perspective.
+-- 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
| 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 20 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
reserved = BC.replicate 8 '\0'
peerID = BC.pack peer_id
-handShake :: Peer -> ByteString -> String -> IO Handle
-handShake (Peer _ ip port) infoHash peerid = do
- let hs = genHandShakeMsg infoHash peerid
+connectToPeer :: Peer -> IO Handle
+connectToPeer peer@(Peer _ ip port) = do
h <- connectTo ip (PortNumber (fromIntegral port))
hSetBuffering h LineBuffering
- hPut h hs
- rlenBS <- hGet h (length (unpack hs))
- putStrLn $ "got handshake from peer: " ++ show rlenBS
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 ()
+
instance Binary PeerMsg where
put msg = case msg of
KeepAliveMsg -> putWord32be 0
msg <- hGet h l
return $ decode $ fromStrict $ concat [lBS, msg]
+sendMsg :: Handle -> PeerMsg -> IO ()
+sendMsg h msg = hPut h bsMsg
+ where bsMsg = toStrict $ encode msg
bsToInt :: ByteString -> Int
bsToInt x = fromIntegral (runGet getWord32be (fromChunks (return x)))
bitfieldToList bs = go bs 0
where go [] _ = []
go (b:bs') pos =
- let setBits = [pos*8 + (toInteger i) | i <- [0..8], testBit b i]
+ let setBits = [pos*8 + toInteger i | i <- [0..8], testBit b i]
in
- setBits ++ (go bs' (pos + 1))
+ setBits ++ go bs' (pos + 1)
--- loop1 :: shake hands with all peers, find out the pieces they have, form PieceData.
-- recvMsg :: Peer -> Handle -> Msg
-msgLoop :: Handle -> ByteString -> IO ()
-msgLoop h pieceHash =
- let numPieces = (toInteger . (`quot` 20) . BC.length) pieceHash
+msgLoop :: PeerState -> PieceMap -> IO ()
+msgLoop pState@(PeerState { meInterested = False , heChoking = True }) pieceStatus =
+ 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
+msgLoop pState@(PeerState { meInterested = True, heChoking = False }) pieceStatus =
+ -- 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)
+ putStrLn $ "piece length = " ++ show pLen
+ 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
+ let fileOffset = if workPiece == 0 then 0 else workPiece * len (pieceStatus ! (workPiece - 1))
+ putStrLn $ "Write into file at offset: " ++ show fileOffset
+ writeFileAtOffset "/tmp/download.file" fileOffset pBS
+ msgLoop pState (adjust (\pieceData -> pieceData { state = Have }) workPiece pieceStatus)
+msgLoop pState pieceStatus = 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
+ 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 pState pieceStatus'
+ UnChokeMsg ->
+ msgLoop (pState { heChoking = False }) pieceStatus
+ _ ->
+ 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
- forever $ do
- msg <- getMsg h
- putStrLn $ "got a " ++ show msg
- case msg of
- BitFieldMsg bss -> do
- let pieceList = bitfieldToList (unpack bss) 0
- putStrLn (show pieceList)
- -- doenload each of the piece
- _ -> putStrLn (show msg)
+ 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 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)
+ createDummyFile "/tmp/download.file" (fromIntegral fileLen)
+ msgLoop state pieceStatus
+
+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