hs-tls/core/Network/TLS/Core.hs
Vincent Hanquez 5ff812b3fa provide a helper for catching exception without doing a catchall.
As a side effect, let AsyncException propagate
2013-11-27 15:08:22 +08:00

131 lines
5.4 KiB
Haskell

{-# OPTIONS_HADDOCK hide #-}
{-# LANGUAGE DeriveDataTypeable, OverloadedStrings, ScopedTypeVariables #-}
-- |
-- Module : Network.TLS.Core
-- License : BSD-style
-- Maintainer : Vincent Hanquez <vincent@snarc.org>
-- Stability : experimental
-- Portability : unknown
--
module Network.TLS.Core
(
-- * Internal packet sending and receiving
sendPacket
, recvPacket
-- * Initialisation and Termination of context
, bye
, handshake
, HandshakeFailed(..)
, ConnectionNotEstablished(..)
-- * Next Protocol Negotiation
, getNegotiatedProtocol
-- * High level API
, Terminated(..)
, sendData
, recvData
, recvData'
) where
import Network.TLS.Context
import Network.TLS.Struct
import Network.TLS.State (getSession)
import Network.TLS.IO
import Network.TLS.Session
import Network.TLS.Handshake
import Network.TLS.Util (catchException)
import Data.Typeable
import qualified Network.TLS.State as S
import qualified Data.ByteString as B
import Data.ByteString.Char8 ()
import qualified Data.ByteString.Lazy as L
import qualified Control.Exception as E
import Control.Monad.State
-- | Early termination exception with the reason and the TLS error associated
data Terminated = Terminated Bool String TLSError
deriving (Eq,Show,Typeable)
instance E.Exception Terminated
-- | notify the context that this side wants to close connection.
-- this is important that it is called before closing the handle, otherwise
-- the session might not be resumable (for version < TLS1.2).
--
-- this doesn't actually close the handle
bye :: MonadIO m => Context -> m ()
bye ctx = sendPacket ctx $ Alert [(AlertLevel_Warning, CloseNotify)]
-- | If the Next Protocol Negotiation extension has been used, this will
-- return get the protocol agreed upon.
getNegotiatedProtocol :: MonadIO m => Context -> m (Maybe B.ByteString)
getNegotiatedProtocol ctx = liftIO $ usingState_ ctx S.getNegotiatedProtocol
-- | sendData sends a bunch of data.
-- It will automatically chunk data to acceptable packet size
sendData :: MonadIO m => Context -> L.ByteString -> m ()
sendData ctx dataToSend = liftIO (checkValid ctx) >> mapM_ sendDataChunk (L.toChunks dataToSend)
where sendDataChunk d
| B.length d > 16384 = do
let (sending, remain) = B.splitAt 16384 d
sendPacket ctx $ AppData sending
sendDataChunk remain
| otherwise = sendPacket ctx $ AppData d
-- | recvData get data out of Data packet, and automatically renegotiate if
-- a Handshake ClientHello is received
recvData :: MonadIO m => Context -> m B.ByteString
recvData ctx = liftIO $ do
checkValid ctx
pkt <- withReadLock ctx $ recvPacket ctx
either onError process pkt
where onError err@(Error_Protocol (reason,fatal,desc)) =
terminate err (if fatal then AlertLevel_Fatal else AlertLevel_Warning) desc reason
onError err =
terminate err AlertLevel_Fatal InternalError (show err)
process (Handshake [ch@(ClientHello {})]) =
-- on server context receiving a client hello == renegotiation
case roleParams $ ctxParams ctx of
Server sparams -> withRWLock ctx (handshakeServerWith sparams ctx ch) >> recvData ctx
Client {} -> let reason = "unexpected client hello in client context" in
terminate (Error_Misc reason) AlertLevel_Fatal UnexpectedMessage reason
process (Handshake [HelloRequest]) =
-- on client context, receiving a hello request == renegotiation
case roleParams $ ctxParams ctx of
Server {} -> let reason = "unexpected hello request in server context" in
terminate (Error_Misc reason) AlertLevel_Fatal UnexpectedMessage reason
Client cparams -> withRWLock ctx (handshakeClient cparams ctx) >> recvData ctx
process (Alert [(AlertLevel_Warning, CloseNotify)]) = tryBye >> setEOF ctx >> return B.empty
process (Alert [(AlertLevel_Fatal, desc)]) = do
setEOF ctx
E.throwIO (Terminated True ("received fatal error: " ++ show desc) (Error_Protocol ("remote side fatal error", True, desc)))
-- when receiving empty appdata, we just retry to get some data.
process (AppData "") = recvData ctx
process (AppData x) = return x
process p = let reason = "unexpected message " ++ show p in
terminate (Error_Misc reason) AlertLevel_Fatal UnexpectedMessage reason
terminate :: TLSError -> AlertLevel -> AlertDescription -> String -> IO a
terminate err level desc reason = do
session <- usingState_ ctx getSession
case session of
Session Nothing -> return ()
Session (Just sid) -> withSessionManager (ctxParams ctx) (\s -> sessionInvalidate s sid)
catchException (sendPacket ctx $ Alert [(level, desc)]) (\_ -> return ())
setEOF ctx
E.throwIO (Terminated False reason err)
-- the other side could have close the connection already, so wrap
-- this in a try and ignore all exceptions
tryBye = catchException (bye ctx) (\_ -> return ())
{-# DEPRECATED recvData' "use recvData that returns strict bytestring" #-}
-- | same as recvData but returns a lazy bytestring.
recvData' :: MonadIO m => Context -> m L.ByteString
recvData' ctx = recvData ctx >>= return . L.fromChunks . (:[])