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|
-- |
-- Copyright : (c) Sam T. 2013
-- License : MIT
-- Maintainer : pxqr.sta@gmail.com
-- Stability : experimental
-- Portability : portable
--
-- This module implement low-level UDP tracker protocol.
-- For more info see: http://www.bittorrent.org/beps/bep_0015.html
--
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
module Network.BitTorrent.Tracker.UDP
( Request(..), Response(..)
) where
import Control.Applicative
import Control.Monad
import Data.Serialize
import Data.Word
import Data.Text
import Data.Text.Encoding
import Network.Socket hiding (Connected)
import Network.Socket.ByteString as BS
import Data.Torrent.Metainfo ()
import Network.BitTorrent.Tracker.Protocol
-- | Connection Id is used for entire tracker session.
newtype ConnId = ConnId { getConnId :: Word64 }
deriving (Show, Eq, Serialize)
-- | Transaction Id is used for within UDP RPC.
newtype TransId = TransId { getTransId :: Word32 }
deriving (Show, Eq, Serialize)
genTransactionId :: IO TransId
genTransactionId = return (TransId 0)
initialConnectionId :: ConnId
initialConnectionId = ConnId 0
data Request = Connect
| Announce AnnounceQuery
| Scrape ScrapeQuery
data Response = Connected
| Announced AnnounceInfo
| Scraped [ScrapeInfo]
| Failed Text
-- TODO rename to message?
data Transaction a = Transaction
{ connId :: !ConnId
, transId :: !TransId
, body :: !a
} deriving Show
type MessageId = Word32
connectId, announceId, scrapeId, errorId :: MessageId
connectId = 0
announceId = 1
scrapeId = 2
errorId = 3
instance Serialize (Transaction Request) where
put Transaction {..} = do
case body of
Connect -> do
put connId
put connectId
put transId
Announce query -> do
put connId
put announceId
put transId
put query
Scrape hashes -> do
put connId
put announceId
put transId
forM_ hashes put
get = do
cid <- get
rid <- getWord32be
tid <- get
bod <- getBody rid
return $ Transaction {
connId = cid
, transId = tid
, body = bod
}
where
getBody :: MessageId -> Get Request
getBody msgId
| msgId == connectId = return Connect
| msgId == announceId = Announce <$> get
| msgId == scrapeId = Scrape <$> many get
| otherwise = fail "unknown message id"
instance Serialize (Transaction Response) where
put Transaction {..} = do
case body of
Connected -> do
put connId
put connectId
put transId
Announced info -> do
put connId
put announceId
put transId
put info
Scraped infos -> do
put connId
put scrapeId
put transId
forM_ infos put
Failed info -> do
put connId
put errorId
put transId
put (encodeUtf8 info)
get = do
cid <- get
rid <- getWord32be
tid <- get
bod <- getBody rid
return $ Transaction {
connId = cid
, transId = tid
, body = bod
}
where
getBody :: MessageId -> Get Response
getBody msgId
| msgId == connectId = return $ Connected
| msgId == announceId = Announced <$> get
| msgId == scrapeId = Scraped <$> many get
| msgId == errorId = do
bs <- get
case decodeUtf8' bs of
Left ex -> fail (show ex)
Right msg -> return $ Failed msg
| otherwise = fail "unknown message id"
maxPacketSize :: Int
maxPacketSize = 98 -- announce request packet
call :: Request -> IO Response
call request = do
tid <- genTransactionId
let trans = Transaction initialConnectionId tid request
let addr = error "TODO"
sock <- socket AF_INET Datagram defaultProtocol
BS.sendAllTo sock (encode trans) addr
(resp, addr') <- BS.recvFrom sock 4096
if addr' /= addr
then error "address mismatch"
else case decode resp of
Left msg -> error msg
Right (Transaction {..}) -> do
if tid /= transId
then error "transaction id mismatch"
else return body
data Connection = Connection
type URI = ()
connectTracker :: URI -> IO Connection
connectTracker = undefined
announceTracker :: Connection -> AnnounceQuery -> IO AnnounceInfo
announceTracker = undefined
scrape :: Connection -> ScrapeQuery -> IO [ScrapeInfo]
scrape = undefined
|
