From 2367c9c0ab45a843cb4d1b8762af4ca06291348c Mon Sep 17 00:00:00 2001
From: Sam Truzjan <pxqr.sta@gmail.com>
Date: Thu, 5 Dec 2013 20:00:01 +0400
Subject: Make extended caps mutable

---
 src/Network/BitTorrent/Exchange/Wire.hs | 73 +++++++++++++++++++++++++--------
 1 file changed, 56 insertions(+), 17 deletions(-)

(limited to 'src/Network/BitTorrent/Exchange/Wire.hs')

diff --git a/src/Network/BitTorrent/Exchange/Wire.hs b/src/Network/BitTorrent/Exchange/Wire.hs
index 68c9b355..6a161762 100644
--- a/src/Network/BitTorrent/Exchange/Wire.hs
+++ b/src/Network/BitTorrent/Exchange/Wire.hs
@@ -4,20 +4,29 @@
 --   Duplex channell
 --   This module control /integrity/ of data send and received.
 --
-
+--
 {-# LANGUAGE DeriveDataTypeable #-}
 module Network.BitTorrent.Exchange.Wire
-       ( -- * Exception
-         ProtocolError (..)
+       ( -- * Wire
+         Wire
+
+         -- ** Exceptions
+       , ProtocolError (..)
        , WireFailure   (..)
        , isWireFailure
+       , disconnectPeer
 
-         -- * Wire
+         -- ** Connection
        , Connection    (..)
-       , Wire
+
+         -- ** Setup
        , runWire
        , connectWire
        , acceptWire
+
+         -- ** Query
+       , getConnection
+       , getExtCaps
        ) where
 
 import Control.Exception
@@ -27,6 +36,7 @@ import Data.Conduit
 import Data.Conduit.Cereal as S
 import Data.Conduit.Network
 import Data.Default
+import Data.IORef
 import Data.Maybe
 import Data.Monoid
 import Data.Serialize as S
@@ -56,6 +66,7 @@ data ProtocolError
   = UnexpectedTopic   InfoHash -- ^ peer replied with unexpected infohash.
   | UnexpectedPeerId  PeerId   -- ^ peer replied with unexpected peer id.
   | UnknownTopic      InfoHash -- ^ peer requested unknown torrent.
+  | HandshakeRefused           -- ^ peer do not send an extended handshake back.
   | InvalidMessage
     { violentSender     :: ChannelSide -- ^ endpoint sent invalid message
     , extensionRequired :: Extension   -- ^
@@ -87,11 +98,11 @@ isWireFailure _ = return ()
 
 data Connection = Connection
   { connCaps         :: !Caps
-  , connExtCaps      :: !ExtendedCaps -- TODO caps can be enabled during communication
+  , connExtCaps      :: !(IORef ExtendedCaps)
   , connTopic        :: !InfoHash
   , connRemotePeerId :: !PeerId
   , connThisPeerId   :: !PeerId
-  } deriving Show
+  }
 
 instance Pretty Connection where
   pretty Connection {..} = "Connection"
@@ -146,6 +157,25 @@ connectToPeer p = do
 
 type Wire = ConduitM Message Message (ReaderT Connection IO)
 
+protocolError :: ProtocolError -> Wire a
+protocolError = monadThrow . ProtocolError
+
+disconnectPeer :: Wire a
+disconnectPeer = monadThrow DisconnectPeer
+
+getExtCaps :: Wire ExtendedCaps
+getExtCaps = do
+  capsRef <- lift $ asks connExtCaps
+  liftIO $ readIORef capsRef
+
+setExtCaps :: ExtendedCaps -> Wire ()
+setExtCaps caps = do
+  capsRef <- lift $ asks connExtCaps
+  liftIO $ writeIORef capsRef caps
+
+getConnection :: Wire Connection
+getConnection = lift ask
+
 validate :: ChannelSide -> Wire ()
 validate side = await >>= maybe (return ()) yieldCheck
   where
@@ -155,9 +185,10 @@ validate side = await >>= maybe (return ()) yieldCheck
         Nothing  -> return ()
         Just ext
           | allowed caps ext -> yield msg
-          |     otherwise    -> monadThrow $ ProtocolError $ InvalidMessage side ext
+          |     otherwise    -> protocolError $ InvalidMessage side ext
 
-validate' action = do
+validateBoth :: Wire () -> Wire ()
+validateBoth action = do
   validate RemotePeer
   action
   validate ThisPeer
@@ -172,17 +203,23 @@ runWire action sock = runReaderT $
 
 sendMessage :: PeerMessage msg => msg -> Wire ()
 sendMessage msg = do
-  ecaps <- lift $ asks connExtCaps
+  ecaps <- getExtCaps
   yield $ envelop ecaps msg
 
 recvMessage :: Wire Message
 recvMessage = undefined
 
-extendedHandshake :: Wire ()
-extendedHandshake = undefined
+extendedHandshake :: ExtendedCaps -> Wire ()
+extendedHandshake caps = do
+  sendMessage $ nullExtendedHandshake caps
+  msg <- recvMessage
+  case msg of
+    Extended (EHandshake ExtendedHandshake {..}) ->
+      setExtCaps $ ehsCaps <> caps
+    _ -> protocolError HandshakeRefused
 
 connectWire :: Handshake -> PeerAddr -> ExtendedCaps -> Wire () -> IO ()
-connectWire hs addr caps wire =
+connectWire hs addr extCaps wire =
   bracket (connectToPeer addr) close $ \ sock -> do
     hs' <- initiateHandshake sock hs
 
@@ -193,12 +230,14 @@ connectWire hs addr caps wire =
       throwIO $ ProtocolError $ UnexpectedPeerId (hsPeerId hs')
 
     let caps = hsReserved hs <> hsReserved hs'
-    if allowed caps ExtExtended
-      then return () else return ()
+    let wire' = if allowed caps ExtExtended
+                then extendedHandshake extCaps >> wire
+                else wire
 
-    runWire wire sock $ Connection
+    extCapsRef <- newIORef def
+    runWire wire' sock $ Connection
       { connCaps         = caps
-      , connExtCaps      = def
+      , connExtCaps      = extCapsRef
       , connTopic        = hsInfoHash hs
       , connRemotePeerId = hsPeerId   hs'
       , connThisPeerId   = hsPeerId   hs
-- 
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