2 - Copyright (C) 2015-2016 Ramakrishnan Muthukrishnan <ram@rkrishnan.org>
4 - This file is part of FuncTorrent.
6 - FuncTorrent is free software; you can redistribute it and/or modify
7 - it under the terms of the GNU General Public License as published by
8 - the Free Software Foundation; either version 3 of the License, or
9 - (at your option) any later version.
11 - FuncTorrent is distributed in the hope that it will be useful,
12 - but WITHOUT ANY WARRANTY; without even the implied warranty of
13 - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 - GNU General Public License for more details.
16 - You should have received a copy of the GNU General Public License
17 - along with FuncTorrent; if not, see <http://www.gnu.org/licenses/>
20 {-# LANGUAGE OverloadedStrings #-}
22 module FuncTorrent.PeerMsgs
31 import Prelude hiding (lookup, concat, replicate, splitAt, take)
33 import System.IO (Handle)
34 import Data.ByteString (ByteString, pack, unpack, concat, hGet, hPut, singleton)
35 import Data.ByteString.Lazy (fromStrict, fromChunks, toStrict)
36 import Data.ByteString.Char8 as BC (splitAt)
37 import qualified Data.ByteString.Char8 as BC (replicate, pack)
38 import Control.Monad (replicateM, liftM)
39 import Control.Applicative (liftA3)
41 import Data.Binary (Binary(..), decode, encode)
42 import Data.Binary.Put (putWord32be, putWord16be, putWord8)
43 import Data.Binary.Get (getWord32be, getWord16be, getWord8, runGet)
45 import FuncTorrent.Utils (toIP, toPort)
47 -- | Peer is a IP address, port tuple
48 data Peer = Peer IP Port
55 data PeerMsg = KeepAliveMsg
61 | BitFieldMsg ByteString
62 | RequestMsg Integer Integer Integer
63 | PieceMsg Integer Integer ByteString
64 | CancelMsg Integer Integer Integer
68 instance Binary PeerMsg where
70 KeepAliveMsg -> putWord32be 0
71 ChokeMsg -> do putWord32be 1
73 UnChokeMsg -> do putWord32be 1
75 InterestedMsg -> do putWord32be 1
77 NotInterestedMsg -> do putWord32be 1
79 HaveMsg i -> do putWord32be 5
81 putWord32be (fromIntegral i)
82 BitFieldMsg bf -> do putWord32be $ fromIntegral (1 + bfListLen)
85 where bfList = unpack bf
86 bfListLen = length bfList
87 RequestMsg i o l -> do putWord32be 13
89 putIndexOffsetLength i o l
90 PieceMsg i o b -> do putWord32be $ fromIntegral (9 + blocklen)
92 putWord32be (fromIntegral i)
93 putWord32be (fromIntegral o)
94 mapM_ putWord8 blockList
95 where blockList = unpack b
96 blocklen = length blockList
97 CancelMsg i o l -> do putWord32be 13
99 putIndexOffsetLength i o l
100 PortMsg p -> do putWord32be 3
102 putWord16be (fromIntegral p)
103 where putIndexOffsetLength i o l = do
104 putWord32be (fromIntegral i)
105 putWord32be (fromIntegral o)
106 putWord32be (fromIntegral l)
113 1 -> return UnChokeMsg
114 2 -> return InterestedMsg
115 3 -> return NotInterestedMsg
116 4 -> fmap (HaveMsg . fromIntegral) getWord32be
117 5 -> fmap (BitFieldMsg . pack) (replicateM (fromIntegral l - 1) getWord8)
118 6 -> liftA3 RequestMsg getInteger getInteger getInteger
119 where getInteger = fromIntegral <$> getWord32be
120 7 -> liftA3 PieceMsg getInteger getInteger (pack <$> replicateM (fromIntegral l - 9) getWord8)
121 where getInteger = fromIntegral <$> getWord32be
122 8 -> liftA3 CancelMsg getInteger getInteger getInteger
123 where getInteger = fromIntegral <$> getWord32be
124 9 -> fmap (PortMsg . fromIntegral) getWord16be
125 _ -> error ("unknown message ID: " ++ show msgid)
127 getMsg :: Handle -> IO PeerMsg
132 then return KeepAliveMsg
135 return $ decode $ fromStrict $ concat [lBS, msg]
137 sendMsg :: Handle -> PeerMsg -> IO ()
138 sendMsg h msg = hPut h bsMsg
139 where bsMsg = toStrict $ encode msg
141 genHandshakeMsg :: ByteString -> String -> ByteString
142 genHandshakeMsg infoHash peer_id = concat [pstrlen, pstr, reserved, infoHash, peerID]
143 where pstrlen = singleton 19
144 pstr = BC.pack "BitTorrent protocol"
145 reserved = BC.replicate 8 '\0'
146 peerID = BC.pack peer_id
148 bsToInt :: ByteString -> Int
149 bsToInt x = fromIntegral (runGet getWord32be (fromChunks (return x)))
151 makePeer :: ByteString -> Peer
152 makePeer peer = Peer (toIP ip') (toPort port')
153 where (ip', port') = splitAt 4 peer