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{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE ScopedTypeVariables #-}
import Control.Concurrent.MVar
import Control.Concurrent.STM
import Control.Exception
import Control.Monad
import qualified Data.ByteString as B
import Data.Function
import Data.Functor.Identity
import qualified Data.IntMap as IntMap
;import Data.IntMap (IntMap)
import qualified Data.Map as Map
;import Data.Map (Map)
import Data.Serialize
import Data.Word
import System.IO
import System.IO.Error
import System.Timeout
import Crypto.Tox
import qualified Data.IntervalSet as IntSet
;import Data.IntervalSet (IntSet)
import Data.Tox.Relay
import Network.Address (getBindAddress)
import Network.StreamServer
import Network.Tox (newCrypto)
hGetPrefixed :: Serialize a => Handle -> IO (Either String a)
hGetPrefixed h = do
mlen <- runGet getWord16be <$> B.hGet h 2
-- We treat parse-fail the same as EOF.
fmap join $ forM mlen $ \len -> runGet get <$> B.hGet h (fromIntegral len)
hGetSized :: forall x. (Sized x, Serialize x) => Handle -> IO (Either String x)
hGetSized h = runGet get <$> B.hGet h len -- We treat parse-fail the same as EOF.
where
ConstSize len = size :: Size x
data RelaySession = RelaySession
{ indexPool :: IntSet -- ^ Ints that are either solicited or associated.
, solicited :: Map PublicKey Int -- ^ Reserved ids, not yet in associated.
, associated :: IntMap (RelayPacket -> IO ()) -- ^ Peers this session is connected to.
}
freshSession :: RelaySession
freshSession = RelaySession
{ indexPool = IntSet.empty
, solicited = Map.empty
, associated = IntMap.empty
}
disconnect :: TVar (Map PublicKey (RelayPacket -> IO (),TVar RelaySession))
-> PublicKey
-> IO ()
disconnect cons who = join $ atomically $ do
Map.lookup who <$> readTVar cons
>>= \case
Nothing -> return $ return ()
Just (_,session) -> do
modifyTVar' cons $ Map.delete who
RelaySession { associated = cs } <- readTVar session
return $ let notifyPeer i send = (send (DisconnectNotification $ key2c i) >>)
in IntMap.foldrWithKey notifyPeer (return ()) cs
relaySession :: TransportCrypto
-> TVar (Map PublicKey (RelayPacket -> IO (),TVar RelaySession))
-> sock
-> Int
-> Handle
-> IO ()
relaySession crypto cons _ conid h = do
-- atomically $ modifyTVar' cons $ IntMap.insert conid h
-- mhello <- fmap (>>= \h -> decryptPayload (computeSharedSecret me (helloFrom h) (helloNonce h)) h) $ hGetSized h
(hGetSized h >>=) $ mapM_ $ \helloE -> do
let me = transportSecret crypto
them = helloFrom helloE
noncef <- lookupNonceFunction crypto me them
let mhello = decryptPayload (noncef $ helloNonce helloE) helloE
forM_ mhello $ \hello -> do
let _ = hello :: Hello Identity
(me',welcome) <- atomically $ do
skey <- transportNewKey crypto
dta <- HelloData (toPublic skey) <$> transportNewNonce crypto
w24 <- transportNewNonce crypto
return (skey, Welcome w24 $ pure dta)
B.hPut h $ encode $ encryptPayload (noncef $ welcomeNonce welcome) welcome
noncef' <- let them' = sessionPublicKey (runIdentity $ helloData hello)
in lookupNonceFunction crypto me' them'
sendPacket <- do
v <- newMVar (sessionBaseNonce $ runIdentity $ welcomeData welcome)
return $ \p -> do
n24 <- takeMVar v
let bs = encode $ encrypt (noncef' n24) $ encodePlain (p :: RelayPacket)
do B.hPut h $ encode (fromIntegral (B.length bs) :: Word16)
B.hPut h bs
`catchIOError` \_ -> return ()
putMVar v (incrementNonce24 n24)
let readPacket n24 = (>>= decrypt (noncef' n24) >=> decodePlain) <$> hGetPrefixed h
base = sessionBaseNonce $ runIdentity $ helloData hello
-- You get 3 seconds to send a session packet.
mpkt0 <- join <$> timeout 3000000 (either (const Nothing) Just <$> readPacket base)
forM_ mpkt0 $ \pkt0 -> do
disconnect cons (helloFrom hello)
session <- atomically $ do
session <- newTVar freshSession
modifyTVar' cons $ Map.insert (helloFrom hello) (sendPacket,session)
return session
handlePacket cons (helloFrom hello) sendPacket session pkt0
flip fix (incrementNonce24 base) $ \loop n24 -> do
m <- readPacket n24
forM_ m $ \p -> do
handlePacket cons (helloFrom hello) sendPacket session p
loop (incrementNonce24 n24)
`finally`
disconnect cons (helloFrom hello)
data R = R { routingRequest :: PublicKey -> IO ConId
, reply :: RelayPacket -> IO ()
, routeOOB :: PublicKey -> IO (Maybe (RelayPacket -> IO ()))
}
handlePacket :: TVar (Map PublicKey (RelayPacket -> IO (), TVar RelaySession))
-> PublicKey
-> (RelayPacket -> IO ())
-> TVar RelaySession
-> RelayPacket
-> IO ()
handlePacket cons me sendToMe session = \case
RoutingRequest them -> join $ atomically $ do
mySession <- readTVar session
mi <- case Map.lookup them (solicited mySession) of
Nothing -> fmap join $ forM (IntSet.nearestOutsider 0 (indexPool mySession)) $ \i -> do
if -120 <= i && i <= 119
then do
writeTVar session mySession
{ indexPool = IntSet.insert i (indexPool mySession)
, solicited = Map.insert them i (solicited mySession)
}
return $ Just i
else return Nothing -- No more slots available.
Just i -> return $ Just i
notifyConnect <- fmap (join . join) $ forM mi $ \i -> do
mp <- Map.lookup them <$> readTVar cons
forM mp $ \(sendToThem,peer) -> do
theirSession <- readTVar peer
forM (Map.lookup me $ solicited theirSession) $ \reserved_id -> do
writeTVar peer theirSession
{ solicited = Map.delete me (solicited theirSession)
, associated = IntMap.insert reserved_id sendToMe (associated theirSession)
}
writeTVar session mySession
{ solicited = Map.delete them (solicited mySession)
, associated = IntMap.insert i sendToThem (associated mySession)
}
return $ do sendToThem $ ConnectNotification (key2c reserved_id)
sendToMe $ ConnectNotification (key2c i)
return $ do sendToMe $ RoutingResponse (maybe badcon key2c mi) them
sequence_ notifyConnect
RelayPing x -> sendToMe $ RelayPong x -- TODO x==0 is invalid. Do we care?
OOBSend them bs -> do
m <- atomically $ Map.lookup them <$> readTVar cons
forM_ m $ \(sendToThem,_) -> sendToThem $ OOBRecv me bs
RelayData con bs -> join $ atomically $ do
-- Data: Data packets can only be sent and received if the
-- corresponding connection_id is connection (a Connect notification
-- has been received from it) if the server receives a Data packet for
-- a non connected or existent connection it will discard it.
mySession <- readTVar session
return $ sequence_ $ do
i <- c2key con
sendToThem <- IntMap.lookup i $ associated mySession
return $ sendToThem $ RelayData _todo bs
_ -> return ()
main :: IO ()
main = do
crypto <- newCrypto
cons <- newTVarIO Map.empty
a <- getBindAddress "33445" True
h <- streamServer ServerConfig
{ serverWarn = hPutStrLn stderr
, serverSession = relaySession crypto cons
}
a
putStrLn $ "ENTER to quit..."
s <- getLine
quitListening h
|
