implement p2p protocol for Handle
This is most of the way to having the p2p protocol working over tor hidden services, at least enough to do git push/pull. The free monad was split into two, one for network operations and the other for local (Annex) operations. This will allow git-remote-tor-annex to run only an IO action, not needing the Annex monad. This commit was sponsored by Remy van Elst on Patreon.
This commit is contained in:
parent
0eaad7ca3a
commit
d50b0f3bb3
3 changed files with 455 additions and 277 deletions
|
@ -7,20 +7,7 @@
|
|||
|
||||
{-# LANGUAGE DeriveFunctor, TemplateHaskell, FlexibleContexts, RankNTypes #-}
|
||||
|
||||
module Remote.Helper.P2P (
|
||||
AuthToken(..),
|
||||
ProtoF(..),
|
||||
runPure,
|
||||
protoDump,
|
||||
auth,
|
||||
checkPresent,
|
||||
lockContentWhile,
|
||||
remove,
|
||||
get,
|
||||
put,
|
||||
connect,
|
||||
serve,
|
||||
) where
|
||||
module Remote.Helper.P2P where
|
||||
|
||||
import qualified Utility.SimpleProtocol as Proto
|
||||
import Types.Key
|
||||
|
@ -33,7 +20,7 @@ import Control.Monad.Free
|
|||
import Control.Monad.Free.TH
|
||||
import Control.Monad.Catch
|
||||
import System.Exit (ExitCode(..))
|
||||
import System.IO (Handle)
|
||||
import System.IO
|
||||
import qualified Data.ByteString.Lazy as L
|
||||
|
||||
newtype AuthToken = AuthToken String
|
||||
|
@ -49,10 +36,6 @@ newtype Len = Len Integer
|
|||
data Service = UploadPack | ReceivePack
|
||||
deriving (Show)
|
||||
|
||||
data RelayData
|
||||
= RelayData L.ByteString
|
||||
| RelayMessage Message
|
||||
|
||||
-- | Messages in the protocol. The peer that makes the connection
|
||||
-- always initiates requests, and the other peer makes responses to them.
|
||||
data Message
|
||||
|
@ -75,264 +58,6 @@ data Message
|
|||
| ERROR String
|
||||
deriving (Show)
|
||||
|
||||
-- | Free monad for implementing actions that use the protocol.
|
||||
data ProtoF next
|
||||
= SendMessage Message next
|
||||
| ReceiveMessage (Message -> next)
|
||||
| SendBytes Len L.ByteString next
|
||||
| ReceiveBytes Len (L.ByteString -> next)
|
||||
-- ^ Lazily reads bytes from peer. Stops once Len are read,
|
||||
-- or if connection is lost, and in either case returns the bytes
|
||||
-- that were read. This allows resuming interrupted transfers.
|
||||
| KeyFileSize Key (Len -> next)
|
||||
-- ^ Checks size of key file (dne = 0)
|
||||
| ReadKeyFile Key Offset (L.ByteString -> next)
|
||||
| WriteKeyFile Key Offset Len L.ByteString (Bool -> next)
|
||||
-- ^ Writes to key file starting at an offset. Returns True
|
||||
-- once the whole content of the key is stored in the key file.
|
||||
--
|
||||
-- Note: The ByteString may not contain the entire remaining content
|
||||
-- of the key. Only once the key file size == Len has the whole
|
||||
-- content been transferred.
|
||||
| CheckAuthToken UUID AuthToken (Bool -> next)
|
||||
| SetPresent Key UUID next
|
||||
| CheckContentPresent Key (Bool -> next)
|
||||
-- ^ Checks if the whole content of the key is locally present.
|
||||
| RemoveKeyFile Key (Bool -> next)
|
||||
-- ^ If the key file is not present, still succeeds.
|
||||
-- May fail if not enough copies to safely drop, etc.
|
||||
| TryLockContent Key (Bool -> Proto ()) next
|
||||
| WriteHandle Handle L.ByteString next
|
||||
-- ^ Try to lock the content of a key, preventing it
|
||||
-- from being deleted, and run the provided protocol action.
|
||||
| Relay Handle (RelayData -> Proto (Maybe ExitCode)) (ExitCode -> next)
|
||||
-- ^ Waits for data to be written to the Handle, and for messages
|
||||
-- to be received from the peer, and passes the data to the
|
||||
-- callback, continuing until it returns an ExitCode.
|
||||
| RelayService Service
|
||||
(Handle -> RelayData -> Proto (Maybe ExitCode))
|
||||
(ExitCode -> next)
|
||||
-- ^ Runs a service, and waits for it to output to stdout,
|
||||
-- and for messages to be received from the peer, and passes
|
||||
-- the data to the callback (which is also passed the service's
|
||||
-- stdin Handle), continuing uniil the service exits.
|
||||
deriving (Functor)
|
||||
|
||||
type Proto = Free ProtoF
|
||||
|
||||
$(makeFree ''ProtoF)
|
||||
|
||||
-- | Running Proto actions purely, to see what they do.
|
||||
runPure :: Show r => Proto r -> [Message] -> [(String, Maybe Message)]
|
||||
runPure (Pure r) _ = [("result: " ++ show r, Nothing)]
|
||||
runPure (Free (SendMessage m next)) ms = (">", Just m):runPure next ms
|
||||
runPure (Free (ReceiveMessage _)) [] = [("not enough Messages provided", Nothing)]
|
||||
runPure (Free (ReceiveMessage next)) (m:ms) = ("<", Just m):runPure (next m) ms
|
||||
runPure (Free (SendBytes _ _ next)) ms = ("> bytes", Nothing):runPure next ms
|
||||
runPure (Free (ReceiveBytes _ next)) ms = ("< bytes", Nothing):runPure (next L.empty) ms
|
||||
runPure (Free (KeyFileSize _ next)) ms = runPure (next (Len 100)) ms
|
||||
runPure (Free (ReadKeyFile _ _ next)) ms = runPure (next L.empty) ms
|
||||
runPure (Free (WriteKeyFile _ _ _ _ next)) ms = runPure (next True) ms
|
||||
runPure (Free (CheckAuthToken _ _ next)) ms = runPure (next True) ms
|
||||
runPure (Free (SetPresent _ _ next)) ms = runPure next ms
|
||||
runPure (Free (CheckContentPresent _ next)) ms = runPure (next False) ms
|
||||
runPure (Free (RemoveKeyFile _ next)) ms = runPure (next True) ms
|
||||
runPure (Free (TryLockContent _ p next)) ms = runPure (p True >> next) ms
|
||||
runPure (Free (WriteHandle _ _ next)) ms = runPure next ms
|
||||
runPure (Free (Relay _ _ next)) ms = runPure (next ExitSuccess) ms
|
||||
runPure (Free (RelayService _ _ next)) ms = runPure (next ExitSuccess) ms
|
||||
|
||||
protoDump :: [(String, Maybe Message)] -> String
|
||||
protoDump = unlines . map protoDump'
|
||||
|
||||
protoDump' :: (String, Maybe Message) -> String
|
||||
protoDump' (s, Nothing) = s
|
||||
protoDump' (s, Just m) = s ++ " " ++ unwords (Proto.formatMessage m)
|
||||
|
||||
auth :: UUID -> AuthToken -> Proto (Maybe UUID)
|
||||
auth myuuid t = do
|
||||
sendMessage (AUTH myuuid t)
|
||||
r <- receiveMessage
|
||||
case r of
|
||||
AUTH_SUCCESS theiruuid -> return $ Just theiruuid
|
||||
AUTH_FAILURE -> return Nothing
|
||||
_ -> do
|
||||
sendMessage (ERROR "auth failed")
|
||||
return Nothing
|
||||
|
||||
checkPresent :: Key -> Proto Bool
|
||||
checkPresent key = do
|
||||
sendMessage (CHECKPRESENT key)
|
||||
checkSuccess
|
||||
|
||||
{- Locks content to prevent it from being dropped, while running an action.
|
||||
-
|
||||
- Note that this only guarantees that the content is locked as long as the
|
||||
- connection to the peer remains up. If the connection is unexpectededly
|
||||
- dropped, the peer will then unlock the content.
|
||||
-}
|
||||
lockContentWhile
|
||||
:: MonadMask m
|
||||
=> (forall r. Proto r -> m r)
|
||||
-> Key
|
||||
-> (Bool -> m ())
|
||||
-> m ()
|
||||
lockContentWhile runproto key a = bracket setup cleanup a
|
||||
where
|
||||
setup = runproto $ do
|
||||
sendMessage (LOCKCONTENT key)
|
||||
checkSuccess
|
||||
cleanup True = runproto $ sendMessage UNLOCKCONTENT
|
||||
cleanup False = return ()
|
||||
|
||||
remove :: Key -> Proto Bool
|
||||
remove key = do
|
||||
sendMessage (REMOVE key)
|
||||
checkSuccess
|
||||
|
||||
get :: Key -> Proto Bool
|
||||
get key = receiveContent key (`GET` key)
|
||||
|
||||
put :: Key -> Proto Bool
|
||||
put key = do
|
||||
sendMessage (PUT key)
|
||||
r <- receiveMessage
|
||||
case r of
|
||||
PUT_FROM offset -> sendContent key offset
|
||||
ALREADY_HAVE -> return True
|
||||
_ -> do
|
||||
sendMessage (ERROR "expected PUT_FROM")
|
||||
return False
|
||||
|
||||
connect :: Service -> Handle -> Handle -> Proto ExitCode
|
||||
connect service hin hout = do
|
||||
sendMessage (CONNECT service)
|
||||
relay hin (relayCallback hout)
|
||||
|
||||
relayCallback :: Handle -> RelayData -> Proto (Maybe ExitCode)
|
||||
relayCallback hout (RelayMessage (DATA len)) = do
|
||||
writeHandle hout =<< receiveBytes len
|
||||
return Nothing
|
||||
relayCallback _ (RelayMessage (CONNECTDONE exitcode)) =
|
||||
return (Just exitcode)
|
||||
relayCallback _ (RelayMessage _) = do
|
||||
sendMessage (ERROR "expected DATA or CONNECTDONE")
|
||||
return (Just (ExitFailure 1))
|
||||
relayCallback _ (RelayData b) = do
|
||||
let len = Len $ fromIntegral $ L.length b
|
||||
sendMessage (DATA len)
|
||||
sendBytes len b
|
||||
return Nothing
|
||||
|
||||
-- | Serve the protocol.
|
||||
--
|
||||
-- Note that if the client sends an unexpected message, the server will
|
||||
-- respond with PTOTO_ERROR, and always continues processing messages.
|
||||
-- Since the protocol is not versioned, this is necessary to handle
|
||||
-- protocol changes robustly, since the client can detect when it's
|
||||
-- talking to a server that does not support some new feature, and fall
|
||||
-- back.
|
||||
--
|
||||
-- When the client sends ERROR to the server, the server gives up,
|
||||
-- since it's not clear what state the client is is, and so not possible to
|
||||
-- recover.
|
||||
serve :: UUID -> Proto ()
|
||||
serve myuuid = go Nothing
|
||||
where
|
||||
go autheduuid = do
|
||||
r <- receiveMessage
|
||||
case r of
|
||||
AUTH theiruuid authtoken -> do
|
||||
ok <- checkAuthToken theiruuid authtoken
|
||||
if ok
|
||||
then do
|
||||
sendMessage (AUTH_SUCCESS myuuid)
|
||||
go (Just theiruuid)
|
||||
else do
|
||||
sendMessage AUTH_FAILURE
|
||||
go autheduuid
|
||||
ERROR _ -> return ()
|
||||
_ -> do
|
||||
case autheduuid of
|
||||
Just theiruuid -> authed theiruuid r
|
||||
Nothing -> sendMessage (ERROR "must AUTH first")
|
||||
go autheduuid
|
||||
|
||||
authed _theiruuid r = case r of
|
||||
LOCKCONTENT key -> tryLockContent key $ \locked -> do
|
||||
sendSuccess locked
|
||||
when locked $ do
|
||||
r' <- receiveMessage
|
||||
case r' of
|
||||
UNLOCKCONTENT -> return ()
|
||||
_ -> sendMessage (ERROR "expected UNLOCKCONTENT")
|
||||
CHECKPRESENT key -> sendSuccess =<< checkContentPresent key
|
||||
REMOVE key -> sendSuccess =<< removeKeyFile key
|
||||
PUT key -> do
|
||||
have <- checkContentPresent key
|
||||
if have
|
||||
then sendMessage ALREADY_HAVE
|
||||
else do
|
||||
ok <- receiveContent key PUT_FROM
|
||||
when ok $
|
||||
setPresent key myuuid
|
||||
-- setPresent not called because the peer may have
|
||||
-- requested the data but not permanatly stored it.
|
||||
GET offset key -> void $ sendContent key offset
|
||||
CONNECT service -> do
|
||||
exitcode <- relayService service relayCallback
|
||||
sendMessage (CONNECTDONE exitcode)
|
||||
_ -> sendMessage (ERROR "unexpected command")
|
||||
|
||||
sendContent :: Key -> Offset -> Proto Bool
|
||||
sendContent key offset = do
|
||||
(len, content) <- readKeyFileLen key offset
|
||||
sendMessage (DATA len)
|
||||
sendBytes len content
|
||||
checkSuccess
|
||||
|
||||
receiveContent :: Key -> (Offset -> Message) -> Proto Bool
|
||||
receiveContent key mkmsg = do
|
||||
Len n <- keyFileSize key
|
||||
let offset = Offset n
|
||||
sendMessage (mkmsg offset)
|
||||
r <- receiveMessage
|
||||
case r of
|
||||
DATA len -> do
|
||||
ok <- writeKeyFile key offset len =<< receiveBytes len
|
||||
sendSuccess ok
|
||||
return ok
|
||||
_ -> do
|
||||
sendMessage (ERROR "expected DATA")
|
||||
return False
|
||||
|
||||
checkSuccess :: Proto Bool
|
||||
checkSuccess = do
|
||||
ack <- receiveMessage
|
||||
case ack of
|
||||
SUCCESS -> return True
|
||||
FAILURE -> return False
|
||||
_ -> do
|
||||
sendMessage (ERROR "expected SUCCESS or FAILURE")
|
||||
return False
|
||||
|
||||
sendSuccess :: Bool -> Proto ()
|
||||
sendSuccess True = sendMessage SUCCESS
|
||||
sendSuccess False = sendMessage FAILURE
|
||||
|
||||
-- Reads key file from an offset. The Len should correspond to
|
||||
-- the length of the ByteString, but to avoid buffering the content
|
||||
-- in memory, is gotten using keyFileSize.
|
||||
readKeyFileLen :: Key -> Offset -> Proto (Len, L.ByteString)
|
||||
readKeyFileLen key (Offset offset) = do
|
||||
(Len totallen) <- keyFileSize key
|
||||
let len = totallen - offset
|
||||
if len <= 0
|
||||
then return (Len 0, L.empty)
|
||||
else do
|
||||
content <- readKeyFile key (Offset offset)
|
||||
return (Len len, content)
|
||||
|
||||
instance Proto.Sendable Message where
|
||||
formatMessage (AUTH uuid authtoken) = ["AUTH", Proto.serialize uuid, Proto.serialize authtoken]
|
||||
formatMessage (AUTH_SUCCESS uuid) = ["AUTH-SUCCESS", Proto.serialize uuid]
|
||||
|
@ -390,3 +115,296 @@ instance Proto.Serializable Service where
|
|||
deserialize "git-upload-pack" = Just UploadPack
|
||||
deserialize "git-receive-pack" = Just ReceivePack
|
||||
deserialize _ = Nothing
|
||||
|
||||
-- | Free monad for the protocol, combining net communication,
|
||||
-- and local actions.
|
||||
data ProtoF c = Net (NetF c) | Local (LocalF c)
|
||||
deriving (Functor)
|
||||
|
||||
type Proto = Free ProtoF
|
||||
|
||||
net :: Net a -> Proto a
|
||||
net = hoistFree Net
|
||||
|
||||
local :: Local a -> Proto a
|
||||
local = hoistFree Local
|
||||
|
||||
data NetF c
|
||||
= SendMessage Message c
|
||||
| ReceiveMessage (Message -> c)
|
||||
| SendBytes Len L.ByteString c
|
||||
| ReceiveBytes Len (L.ByteString -> c)
|
||||
| Relay RelayHandle
|
||||
(RelayData -> Net (Maybe ExitCode))
|
||||
(ExitCode -> c)
|
||||
-- ^ Waits for data to be written to the RelayHandle, and for messages
|
||||
-- to be received from the peer, and passes the data to the
|
||||
-- callback, continuing until it returns an ExitCode.
|
||||
| RelayService Service
|
||||
(RelayHandle -> RelayData -> Net (Maybe ExitCode))
|
||||
(ExitCode -> c)
|
||||
-- ^ Runs a service, and waits for it to output to stdout,
|
||||
-- and for messages to be received from the peer, and passes
|
||||
-- the data to the callback (which is also passed the service's
|
||||
-- stdin RelayHandle), continuing uniil the service exits.
|
||||
| WriteRelay RelayHandle L.ByteString c
|
||||
-- ^ Write data to a relay's handle, flushing it immediately.
|
||||
deriving (Functor)
|
||||
|
||||
type Net = Free NetF
|
||||
|
||||
data RelayData
|
||||
= RelayData L.ByteString
|
||||
| RelayMessage Message
|
||||
|
||||
newtype RelayHandle = RelayHandle Handle
|
||||
|
||||
data LocalF c
|
||||
-- ^ Lazily reads bytes from peer. Stops once Len are read,
|
||||
-- or if connection is lost, and in either case returns the bytes
|
||||
-- that were read. This allows resuming interrupted transfers.
|
||||
= KeyFileSize Key (Len -> c)
|
||||
-- ^ Checks size of key file (dne = 0)
|
||||
| ReadKeyFile Key Offset (L.ByteString -> c)
|
||||
| WriteKeyFile Key Offset Len L.ByteString (Bool -> c)
|
||||
-- ^ Writes to key file starting at an offset. Returns True
|
||||
-- once the whole content of the key is stored in the key file.
|
||||
--
|
||||
-- Note: The ByteString may not contain the entire remaining content
|
||||
-- of the key. Only once the key file size == Len has the whole
|
||||
-- content been transferred.
|
||||
| CheckAuthToken UUID AuthToken (Bool -> c)
|
||||
| SetPresent Key UUID c
|
||||
| CheckContentPresent Key (Bool -> c)
|
||||
-- ^ Checks if the whole content of the key is locally present.
|
||||
| RemoveKeyFile Key (Bool -> c)
|
||||
-- ^ If the key file is not present, still succeeds.
|
||||
-- May fail if not enough copies to safely drop, etc.
|
||||
| TryLockContent Key (Bool -> Proto ()) c
|
||||
-- ^ Try to lock the content of a key, preventing it
|
||||
-- from being deleted, and run the provided protocol action.
|
||||
deriving (Functor)
|
||||
|
||||
type Local = Free LocalF
|
||||
|
||||
-- Generate sendMessage etc functions for all free monad constructors.
|
||||
$(makeFree ''NetF)
|
||||
$(makeFree ''LocalF)
|
||||
|
||||
-- | Running Proto actions purely, to see what they do.
|
||||
runPure :: Show r => Proto r -> [Message] -> [(String, Maybe Message)]
|
||||
runPure (Pure r) _ = [("result: " ++ show r, Nothing)]
|
||||
runPure (Free (Net n)) ms = runNet n ms
|
||||
runPure (Free (Local n)) ms = runLocal n ms
|
||||
|
||||
runNet :: Show r => NetF (Proto r) -> [Message] -> [(String, Maybe Message)]
|
||||
runNet (SendMessage m next) ms = (">", Just m):runPure next ms
|
||||
runNet (ReceiveMessage _) [] = [("not enough Messages provided", Nothing)]
|
||||
runNet (ReceiveMessage next) (m:ms) = ("<", Just m):runPure (next m) ms
|
||||
runNet (SendBytes _ _ next) ms = ("> bytes", Nothing):runPure next ms
|
||||
runNet (ReceiveBytes _ next) ms = ("< bytes", Nothing):runPure (next L.empty) ms
|
||||
runNet (Relay _ _ next) ms = runPure (next ExitSuccess) ms
|
||||
runNet (RelayService _ _ next) ms = runPure (next ExitSuccess) ms
|
||||
runNet (WriteRelay _ _ next) ms = runPure next ms
|
||||
|
||||
runLocal :: Show r => LocalF (Proto r) -> [Message] -> [(String, Maybe Message)]
|
||||
runLocal (KeyFileSize _ next) ms = runPure (next (Len 100)) ms
|
||||
runLocal (ReadKeyFile _ _ next) ms = runPure (next L.empty) ms
|
||||
runLocal (WriteKeyFile _ _ _ _ next) ms = runPure (next True) ms
|
||||
runLocal (CheckAuthToken _ _ next) ms = runPure (next True) ms
|
||||
runLocal (SetPresent _ _ next) ms = runPure next ms
|
||||
runLocal (CheckContentPresent _ next) ms = runPure (next False) ms
|
||||
runLocal (RemoveKeyFile _ next) ms = runPure (next True) ms
|
||||
runLocal (TryLockContent _ p next) ms = runPure (p True >> next) ms
|
||||
|
||||
protoDump :: [(String, Maybe Message)] -> String
|
||||
protoDump = unlines . map protoDump'
|
||||
|
||||
protoDump' :: (String, Maybe Message) -> String
|
||||
protoDump' (s, Nothing) = s
|
||||
protoDump' (s, Just m) = s ++ " " ++ unwords (Proto.formatMessage m)
|
||||
|
||||
auth :: UUID -> AuthToken -> Proto (Maybe UUID)
|
||||
auth myuuid t = do
|
||||
net $ sendMessage (AUTH myuuid t)
|
||||
r <- net receiveMessage
|
||||
case r of
|
||||
AUTH_SUCCESS theiruuid -> return $ Just theiruuid
|
||||
AUTH_FAILURE -> return Nothing
|
||||
_ -> do
|
||||
net $ sendMessage (ERROR "auth failed")
|
||||
return Nothing
|
||||
|
||||
checkPresent :: Key -> Proto Bool
|
||||
checkPresent key = do
|
||||
net $ sendMessage (CHECKPRESENT key)
|
||||
checkSuccess
|
||||
|
||||
{- Locks content to prevent it from being dropped, while running an action.
|
||||
-
|
||||
- Note that this only guarantees that the content is locked as long as the
|
||||
- connection to the peer remains up. If the connection is unexpectededly
|
||||
- dropped, the peer will then unlock the content.
|
||||
-}
|
||||
lockContentWhile
|
||||
:: MonadMask m
|
||||
=> (forall r. Proto r -> m r)
|
||||
-> Key
|
||||
-> (Bool -> m ())
|
||||
-> m ()
|
||||
lockContentWhile runproto key a = bracket setup cleanup a
|
||||
where
|
||||
setup = runproto $ do
|
||||
net $ sendMessage (LOCKCONTENT key)
|
||||
checkSuccess
|
||||
cleanup True = runproto $ net $ sendMessage UNLOCKCONTENT
|
||||
cleanup False = return ()
|
||||
|
||||
remove :: Key -> Proto Bool
|
||||
remove key = do
|
||||
net $ sendMessage (REMOVE key)
|
||||
checkSuccess
|
||||
|
||||
get :: Key -> Proto Bool
|
||||
get key = receiveContent key (`GET` key)
|
||||
|
||||
put :: Key -> Proto Bool
|
||||
put key = do
|
||||
net $ sendMessage (PUT key)
|
||||
r <- net receiveMessage
|
||||
case r of
|
||||
PUT_FROM offset -> sendContent key offset
|
||||
ALREADY_HAVE -> return True
|
||||
_ -> do
|
||||
net $ sendMessage (ERROR "expected PUT_FROM")
|
||||
return False
|
||||
|
||||
-- | Serve the protocol.
|
||||
--
|
||||
-- Note that if the client sends an unexpected message, the server will
|
||||
-- respond with PTOTO_ERROR, and always continues processing messages.
|
||||
-- Since the protocol is not versioned, this is necessary to handle
|
||||
-- protocol changes robustly, since the client can detect when it's
|
||||
-- talking to a server that does not support some new feature, and fall
|
||||
-- back.
|
||||
--
|
||||
-- When the client sends ERROR to the server, the server gives up,
|
||||
-- since it's not clear what state the client is is, and so not possible to
|
||||
-- recover.
|
||||
serve :: UUID -> Proto ()
|
||||
serve myuuid = go Nothing
|
||||
where
|
||||
go autheduuid = do
|
||||
r <- net receiveMessage
|
||||
case r of
|
||||
AUTH theiruuid authtoken -> do
|
||||
ok <- local $ checkAuthToken theiruuid authtoken
|
||||
if ok
|
||||
then do
|
||||
net $ sendMessage (AUTH_SUCCESS myuuid)
|
||||
go (Just theiruuid)
|
||||
else do
|
||||
net $ sendMessage AUTH_FAILURE
|
||||
go autheduuid
|
||||
ERROR _ -> return ()
|
||||
_ -> do
|
||||
case autheduuid of
|
||||
Just theiruuid -> authed theiruuid r
|
||||
Nothing -> net $ sendMessage (ERROR "must AUTH first")
|
||||
go autheduuid
|
||||
|
||||
authed _theiruuid r = case r of
|
||||
LOCKCONTENT key -> local $ tryLockContent key $ \locked -> do
|
||||
sendSuccess locked
|
||||
when locked $ do
|
||||
r' <- net receiveMessage
|
||||
case r' of
|
||||
UNLOCKCONTENT -> return ()
|
||||
_ -> net $ sendMessage (ERROR "expected UNLOCKCONTENT")
|
||||
CHECKPRESENT key -> sendSuccess =<< local (checkContentPresent key)
|
||||
REMOVE key -> sendSuccess =<< local (removeKeyFile key)
|
||||
PUT key -> do
|
||||
have <- local $ checkContentPresent key
|
||||
if have
|
||||
then net $ sendMessage ALREADY_HAVE
|
||||
else do
|
||||
ok <- receiveContent key PUT_FROM
|
||||
when ok $
|
||||
local $ setPresent key myuuid
|
||||
-- setPresent not called because the peer may have
|
||||
-- requested the data but not permanatly stored it.
|
||||
GET offset key -> void $ sendContent key offset
|
||||
CONNECT service -> do
|
||||
exitcode <- net $ relayService service relayCallback
|
||||
net $ sendMessage (CONNECTDONE exitcode)
|
||||
_ -> net $ sendMessage (ERROR "unexpected command")
|
||||
|
||||
sendContent :: Key -> Offset -> Proto Bool
|
||||
sendContent key offset = do
|
||||
(len, content) <- readKeyFileLen key offset
|
||||
net $ sendMessage (DATA len)
|
||||
net $ sendBytes len content
|
||||
checkSuccess
|
||||
|
||||
receiveContent :: Key -> (Offset -> Message) -> Proto Bool
|
||||
receiveContent key mkmsg = do
|
||||
Len n <- local $ keyFileSize key
|
||||
let offset = Offset n
|
||||
net $ sendMessage (mkmsg offset)
|
||||
r <- net receiveMessage
|
||||
case r of
|
||||
DATA len -> do
|
||||
ok <- local . writeKeyFile key offset len
|
||||
=<< net (receiveBytes len)
|
||||
sendSuccess ok
|
||||
return ok
|
||||
_ -> do
|
||||
net $ sendMessage (ERROR "expected DATA")
|
||||
return False
|
||||
|
||||
checkSuccess :: Proto Bool
|
||||
checkSuccess = do
|
||||
ack <- net receiveMessage
|
||||
case ack of
|
||||
SUCCESS -> return True
|
||||
FAILURE -> return False
|
||||
_ -> do
|
||||
net $ sendMessage (ERROR "expected SUCCESS or FAILURE")
|
||||
return False
|
||||
|
||||
sendSuccess :: Bool -> Proto ()
|
||||
sendSuccess True = net $ sendMessage SUCCESS
|
||||
sendSuccess False = net $ sendMessage FAILURE
|
||||
|
||||
-- Reads key file from an offset. The Len should correspond to
|
||||
-- the length of the ByteString, but to avoid buffering the content
|
||||
-- in memory, is gotten using keyFileSize.
|
||||
readKeyFileLen :: Key -> Offset -> Proto (Len, L.ByteString)
|
||||
readKeyFileLen key (Offset offset) = do
|
||||
(Len totallen) <- local $ keyFileSize key
|
||||
let len = totallen - offset
|
||||
if len <= 0
|
||||
then return (Len 0, L.empty)
|
||||
else do
|
||||
content <- local $ readKeyFile key (Offset offset)
|
||||
return (Len len, content)
|
||||
|
||||
connect :: Service -> Handle -> Handle -> Proto ExitCode
|
||||
connect service hin hout = do
|
||||
net $ sendMessage (CONNECT service)
|
||||
net $ relay (RelayHandle hin) (relayCallback (RelayHandle hout))
|
||||
|
||||
relayCallback :: RelayHandle -> RelayData -> Net (Maybe ExitCode)
|
||||
relayCallback hout (RelayMessage (DATA len)) = do
|
||||
writeRelay hout =<< receiveBytes len
|
||||
return Nothing
|
||||
relayCallback _ (RelayMessage (CONNECTDONE exitcode)) =
|
||||
return (Just exitcode)
|
||||
relayCallback _ (RelayMessage _) = do
|
||||
sendMessage (ERROR "expected DATA or CONNECTDONE")
|
||||
return (Just (ExitFailure 1))
|
||||
relayCallback _ (RelayData b) = do
|
||||
let len = Len $ fromIntegral $ L.length b
|
||||
sendMessage (DATA len)
|
||||
sendBytes len b
|
||||
return Nothing
|
||||
|
|
Loading…
Add table
Add a link
Reference in a new issue