servers: blocking records for content moderation (#1430)

* servers: blocking records for content moderation

* update

* encode BLOCKED as AUTH in old versions

* update

* unblock queue command

* test, status command

src/Simplex/FileTransfer/Protocol.hs

@@ -25,7 +25,7 @@ import Data.List.NonEmpty (NonEmpty (..))
 import Data.Maybe (isNothing)
 import Data.Type.Equality
 import Data.Word (Word32)
-import Simplex.FileTransfer.Transport (XFTPErrorType (..), XFTPVersion, xftpClientHandshakeStub)
+import Simplex.FileTransfer.Transport (XFTPErrorType (..), XFTPVersion, blockedFilesXFTPVersion, xftpClientHandshakeStub)
 import Simplex.Messaging.Client (authTransmission)
 import qualified Simplex.Messaging.Crypto as C
 import Simplex.Messaging.Encoding
@@ -276,12 +276,14 @@ data FileResponse
 
 instance ProtocolEncoding XFTPVersion XFTPErrorType FileResponse where
   type Tag FileResponse = FileResponseTag
-  encodeProtocol _v = \case
+  encodeProtocol v = \case
     FRSndIds fId rIds -> e (FRSndIds_, ' ', fId, rIds)
     FRRcvIds rIds -> e (FRRcvIds_, ' ', rIds)
     FRFile rDhKey nonce -> e (FRFile_, ' ', rDhKey, nonce)
     FROk -> e FROk_
-    FRErr err -> e (FRErr_, ' ', err)
+    FRErr err -> case err of
+      BLOCKED _ | v < blockedFilesXFTPVersion -> e (FRErr_, ' ', AUTH)
+      _ -> e (FRErr_, ' ', err)
     FRPong -> e FRPong_
     where
       e :: Encoding a => a -> ByteString

src/Simplex/FileTransfer/Server.hs

@@ -53,11 +53,11 @@ import qualified Simplex.Messaging.Crypto as C
 import qualified Simplex.Messaging.Crypto.Lazy as LC
 import Simplex.Messaging.Encoding
 import Simplex.Messaging.Encoding.String
-import Simplex.Messaging.Protocol (CorrId (..), EntityId (..), RcvPublicAuthKey, RcvPublicDhKey, RecipientId, TransmissionAuth, pattern NoEntity)
+import Simplex.Messaging.Protocol (CorrId (..), BlockingInfo, EntityId (..), RcvPublicAuthKey, RcvPublicDhKey, RecipientId, TransmissionAuth, pattern NoEntity)
 import Simplex.Messaging.Server (dummyVerifyCmd, verifyCmdAuthorization)
 import Simplex.Messaging.Server.Control (CPClientRole (..))
 import Simplex.Messaging.Server.Expiration
-import Simplex.Messaging.Server.QueueStore (RoundedSystemTime, getRoundedSystemTime)
+import Simplex.Messaging.Server.QueueStore (RoundedSystemTime, ServerEntityStatus (..), getRoundedSystemTime)
 import Simplex.Messaging.Server.Stats
 import Simplex.Messaging.TMap (TMap)
 import qualified Simplex.Messaging.TMap as TM
@@ -287,11 +287,15 @@ xftpServer cfg@XFTPServerConfig {xftpPort, transportConfig, inactiveClientExpira
               CPDelete fileId -> withUserRole $ unliftIO u $ do
                 fs <- asks store
                 r <- runExceptT $ do
-                  let asSender = ExceptT . atomically $ getFile fs SFSender fileId
-                  let asRecipient = ExceptT . atomically $ getFile fs SFRecipient fileId
-                  (fr, _) <- asSender `catchError` const asRecipient
+                  (fr, _) <- ExceptT $ atomically $ getFile fs SFSender fileId
                   ExceptT $ deleteServerFile_ fr
                 liftIO . hPutStrLn h $ either (\e -> "error: " <> show e) (\() -> "ok") r
+              CPBlock fileId info -> withUserRole $ unliftIO u $ do
+                fs <- asks store
+                r <- runExceptT $ do
+                  (fr, _) <- ExceptT $ atomically $ getFile fs SFSender fileId
+                  ExceptT $ blockServerFile fr info
+                liftIO . hPutStrLn h $ either (\e -> "error: " <> show e) (\() -> "ok") r
               CPHelp -> hPutStrLn h "commands: stats-rts, delete, help, quit"
               CPQuit -> pure ()
               CPSkip -> pure ()
@@ -321,7 +325,7 @@ processRequest XFTPTransportRequest {thParams, reqBody = body@HTTP2Body {bodyHea
               let THandleParams {thAuth} = thParams
               verifyXFTPTransmission ((,C.cbNonce (bs corrId)) <$> thAuth) sig_ signed fId cmd >>= \case
                 VRVerified req -> uncurry send =<< processXFTPRequest body req
-                VRFailed -> send (FRErr AUTH) Nothing
+                VRFailed e -> send (FRErr e) Nothing
             Left e -> send (FRErr e) Nothing
           where
             send resp = sendXFTPResponse (corrId, fId, resp)
@@ -355,7 +359,7 @@ randomDelay = do
     threadDelay $ (d * (1000 + pc)) `div` 1000
 #endif
 
-data VerificationResult = VRVerified XFTPRequest | VRFailed
+data VerificationResult = VRVerified XFTPRequest | VRFailed XFTPErrorType
 
 verifyXFTPTransmission :: Maybe (THandleAuth 'TServer, C.CbNonce) -> Maybe TransmissionAuth -> ByteString -> XFTPFileId -> FileCmd -> M VerificationResult
 verifyXFTPTransmission auth_ tAuth authorized fId cmd =
@@ -367,13 +371,19 @@ verifyXFTPTransmission auth_ tAuth authorized fId cmd =
     verifyCmd :: SFileParty p -> M VerificationResult
     verifyCmd party = do
       st <- asks store
-      atomically $ verify <$> getFile st party fId
+      atomically $ verify =<< getFile st party fId
       where
         verify = \case
-          Right (fr, k) -> XFTPReqCmd fId fr cmd `verifyWith` k
-          _ -> maybe False (dummyVerifyCmd Nothing authorized) tAuth `seq` VRFailed
+          Right (fr, k) -> result <$> readTVar (fileStatus fr)
+            where
+              result = \case
+                EntityActive -> XFTPReqCmd fId fr cmd `verifyWith` k
+                EntityBlocked info -> VRFailed $ BLOCKED info
+                EntityOff -> noFileAuth
+          Left _ -> pure noFileAuth
+        noFileAuth = maybe False (dummyVerifyCmd Nothing authorized) tAuth `seq` VRFailed AUTH
     -- TODO verify with DH authorization
-    req `verifyWith` k = if verifyCmdAuthorization auth_ tAuth authorized k then VRVerified req else VRFailed
+    req `verifyWith` k = if verifyCmdAuthorization auth_ tAuth authorized k then VRVerified req else VRFailed AUTH
 
 processXFTPRequest :: HTTP2Body -> XFTPRequest -> M (FileResponse, Maybe ServerFile)
 processXFTPRequest HTTP2Body {bodyPart} = \case
@@ -390,7 +400,7 @@ processXFTPRequest HTTP2Body {bodyPart} = \case
     FACK -> noFile =<< ackFileReception fId fr
     -- it should never get to the commands below, they are passed in other constructors of XFTPRequest
     FNEW {} -> noFile $ FRErr INTERNAL
-    PING -> noFile FRPong
+    PING -> noFile $ FRErr INTERNAL
   XFTPReqPing -> noFile FRPong
   where
     noFile resp = pure (resp, Nothing)
@@ -518,15 +528,24 @@ processXFTPRequest HTTP2Body {bodyPart} = \case
       pure FROk
 
 deleteServerFile_ :: FileRec -> M (Either XFTPErrorType ())
-deleteServerFile_ FileRec {senderId, fileInfo, filePath} = do
+deleteServerFile_ fr@FileRec {senderId} = do
   withFileLog (`logDeleteFile` senderId)
-  runExceptT $ do
+  deleteOrBlockServerFile_ fr filesDeleted (`deleteFile` senderId)
+
+-- this also deletes the file from storage, but doesn't include it in delete statistics
+blockServerFile :: FileRec -> BlockingInfo -> M (Either XFTPErrorType ())
+blockServerFile fr@FileRec {senderId} info = do
+  withFileLog $ \sl -> logBlockFile sl senderId info
+  deleteOrBlockServerFile_ fr filesBlocked $ \st -> blockFile st senderId info True
+
+deleteOrBlockServerFile_ :: FileRec -> (FileServerStats -> IORef Int) -> (FileStore -> STM (Either XFTPErrorType ())) -> M (Either XFTPErrorType ())
+deleteOrBlockServerFile_ FileRec {filePath, fileInfo} stat storeAction = runExceptT $ do
     path <- readTVarIO filePath
     stats <- asks serverStats
     ExceptT $ first (\(_ :: SomeException) -> FILE_IO) <$> try (forM_ path $ \p -> whenM (doesFileExist p) (removeFile p >> deletedStats stats))
     st <- asks store
-    void $ atomically $ deleteFile st senderId
-    lift $ incFileStat filesDeleted
+    void $ atomically $ storeAction st
+    lift $ incFileStat stat
   where
     deletedStats stats = do
       liftIO $ atomicModifyIORef'_ (filesCount stats) (subtract 1)

src/Simplex/FileTransfer/Server/Control.hs

@@ -6,12 +6,13 @@ module Simplex.FileTransfer.Server.Control where
 import qualified Data.Attoparsec.ByteString.Char8 as A
 import Simplex.FileTransfer.Protocol (XFTPFileId)
 import Simplex.Messaging.Encoding.String
-import Simplex.Messaging.Protocol (BasicAuth)
+import Simplex.Messaging.Protocol (BasicAuth, BlockingInfo)
 
 data ControlProtocol
   = CPAuth BasicAuth
   | CPStatsRTS
   | CPDelete XFTPFileId
+  | CPBlock XFTPFileId BlockingInfo
   | CPHelp
   | CPQuit
   | CPSkip
@@ -21,6 +22,7 @@ instance StrEncoding ControlProtocol where
     CPAuth tok -> "auth " <> strEncode tok
     CPStatsRTS -> "stats-rts"
     CPDelete fId -> strEncode (Str "delete", fId)
+    CPBlock fId info -> strEncode (Str "block", fId, info)
     CPHelp -> "help"
     CPQuit -> "quit"
     CPSkip -> ""
@@ -29,6 +31,7 @@ instance StrEncoding ControlProtocol where
       "auth" -> CPAuth <$> _strP
       "stats-rts" -> pure CPStatsRTS
       "delete" -> CPDelete <$> _strP
+      "block" -> CPBlock <$> _strP <*> _strP
       "help" -> pure CPHelp
       "quit" -> pure CPQuit
       "" -> pure CPSkip

src/Simplex/FileTransfer/Server/Stats.hs

@@ -20,6 +20,7 @@ data FileServerStats = FileServerStats
     filesUploaded :: IORef Int,
     filesExpired :: IORef Int,
     filesDeleted :: IORef Int,
+    filesBlocked :: IORef Int,
     filesDownloaded :: PeriodStats,
     fileDownloads :: IORef Int,
     fileDownloadAcks :: IORef Int,
@@ -34,6 +35,7 @@ data FileServerStatsData = FileServerStatsData
     _filesUploaded :: Int,
     _filesExpired :: Int,
     _filesDeleted :: Int,
+    _filesBlocked :: Int,
     _filesDownloaded :: PeriodStatsData,
     _fileDownloads :: Int,
     _fileDownloadAcks :: Int,
@@ -50,12 +52,13 @@ newFileServerStats ts = do
   filesUploaded <- newIORef 0
   filesExpired <- newIORef 0
   filesDeleted <- newIORef 0
+  filesBlocked <- newIORef 0
   filesDownloaded <- newPeriodStats
   fileDownloads <- newIORef 0
   fileDownloadAcks <- newIORef 0
   filesCount <- newIORef 0
   filesSize <- newIORef 0
-  pure FileServerStats {fromTime, filesCreated, fileRecipients, filesUploaded, filesExpired, filesDeleted, filesDownloaded, fileDownloads, fileDownloadAcks, filesCount, filesSize}
+  pure FileServerStats {fromTime, filesCreated, fileRecipients, filesUploaded, filesExpired, filesDeleted, filesBlocked, filesDownloaded, fileDownloads, fileDownloadAcks, filesCount, filesSize}
 
 getFileServerStatsData :: FileServerStats -> IO FileServerStatsData
 getFileServerStatsData s = do
@@ -65,12 +68,13 @@ getFileServerStatsData s = do
   _filesUploaded <- readIORef $ filesUploaded s
   _filesExpired <- readIORef $ filesExpired s
   _filesDeleted <- readIORef $ filesDeleted s
+  _filesBlocked <- readIORef $ filesBlocked s
   _filesDownloaded <- getPeriodStatsData $ filesDownloaded s
   _fileDownloads <- readIORef $ fileDownloads s
   _fileDownloadAcks <- readIORef $ fileDownloadAcks s
   _filesCount <- readIORef $ filesCount s
   _filesSize <- readIORef $ filesSize s
-  pure FileServerStatsData {_fromTime, _filesCreated, _fileRecipients, _filesUploaded, _filesExpired, _filesDeleted, _filesDownloaded, _fileDownloads, _fileDownloadAcks, _filesCount, _filesSize}
+  pure FileServerStatsData {_fromTime, _filesCreated, _fileRecipients, _filesUploaded, _filesExpired, _filesDeleted, _filesBlocked, _filesDownloaded, _fileDownloads, _fileDownloadAcks, _filesCount, _filesSize}
 
 -- this function is not thread safe, it is used on server start only
 setFileServerStats :: FileServerStats -> FileServerStatsData -> IO ()
@@ -81,6 +85,7 @@ setFileServerStats s d = do
   writeIORef (filesUploaded s) $! _filesUploaded d
   writeIORef (filesExpired s) $! _filesExpired d
   writeIORef (filesDeleted s) $! _filesDeleted d
+  writeIORef (filesBlocked s) $! _filesBlocked d
   setPeriodStats (filesDownloaded s) $! _filesDownloaded d
   writeIORef (fileDownloads s) $! _fileDownloads d
   writeIORef (fileDownloadAcks s) $! _fileDownloadAcks d
@@ -88,7 +93,7 @@ setFileServerStats s d = do
   writeIORef (filesSize s) $! _filesSize d
 
 instance StrEncoding FileServerStatsData where
-  strEncode FileServerStatsData {_fromTime, _filesCreated, _fileRecipients, _filesUploaded, _filesExpired, _filesDeleted, _filesDownloaded, _fileDownloads, _fileDownloadAcks, _filesCount, _filesSize} =
+  strEncode FileServerStatsData {_fromTime, _filesCreated, _fileRecipients, _filesUploaded, _filesExpired, _filesDeleted, _filesBlocked, _filesDownloaded, _fileDownloads, _fileDownloadAcks, _filesCount, _filesSize} =
     B.unlines
       [ "fromTime=" <> strEncode _fromTime,
         "filesCreated=" <> strEncode _filesCreated,
@@ -96,6 +101,7 @@ instance StrEncoding FileServerStatsData where
         "filesUploaded=" <> strEncode _filesUploaded,
         "filesExpired=" <> strEncode _filesExpired,
         "filesDeleted=" <> strEncode _filesDeleted,
+        "filesBlocked=" <> strEncode _filesBlocked,
         "filesCount=" <> strEncode _filesCount,
         "filesSize=" <> strEncode _filesSize,
         "filesDownloaded:",
@@ -110,9 +116,10 @@ instance StrEncoding FileServerStatsData where
     _filesUploaded <- "filesUploaded=" *> strP <* A.endOfLine
     _filesExpired <- "filesExpired=" *> strP <* A.endOfLine <|> pure 0
     _filesDeleted <- "filesDeleted=" *> strP <* A.endOfLine
+    _filesBlocked <- "filesBlocked=" *> strP <* A.endOfLine
     _filesCount <- "filesCount=" *> strP <* A.endOfLine <|> pure 0
     _filesSize <- "filesSize=" *> strP <* A.endOfLine <|> pure 0
     _filesDownloaded <- "filesDownloaded:" *> A.endOfLine *> strP <* A.endOfLine
     _fileDownloads <- "fileDownloads=" *> strP <* A.endOfLine
     _fileDownloadAcks <- "fileDownloadAcks=" *> strP <* A.endOfLine
-    pure FileServerStatsData {_fromTime, _filesCreated, _fileRecipients, _filesUploaded, _filesExpired, _filesDeleted, _filesDownloaded, _fileDownloads, _fileDownloadAcks, _filesCount, _filesSize}
+    pure FileServerStatsData {_fromTime, _filesCreated, _fileRecipients, _filesUploaded, _filesExpired, _filesDeleted, _filesBlocked, _filesDownloaded, _fileDownloads, _fileDownloadAcks, _filesCount, _filesSize}

src/Simplex/FileTransfer/Server/Store.hs

@@ -13,6 +13,7 @@ module Simplex.FileTransfer.Server.Store
     setFilePath,
     addRecipient,
     deleteFile,
+    blockFile,
     deleteRecipient,
     expiredFilePath,
     getFile,
@@ -22,6 +23,7 @@ module Simplex.FileTransfer.Server.Store
 where
 
 import Control.Concurrent.STM
+import Control.Monad
 import qualified Data.Attoparsec.ByteString.Char8 as A
 import Data.Int (Int64)
 import Data.Set (Set)
@@ -30,8 +32,8 @@ import Simplex.FileTransfer.Protocol (FileInfo (..), SFileParty (..), XFTPFileId
 import Simplex.FileTransfer.Transport (XFTPErrorType (..))
 import qualified Simplex.Messaging.Crypto as C
 import Simplex.Messaging.Encoding.String
-import Simplex.Messaging.Protocol (RcvPublicAuthKey, RecipientId, SenderId)
-import Simplex.Messaging.Server.QueueStore (RoundedSystemTime (..))
+import Simplex.Messaging.Protocol (BlockingInfo, RcvPublicAuthKey, RecipientId, SenderId)
+import Simplex.Messaging.Server.QueueStore (RoundedSystemTime (..), ServerEntityStatus (..))
 import Simplex.Messaging.TMap (TMap)
 import qualified Simplex.Messaging.TMap as TM
 import Simplex.Messaging.Util (ifM, ($>>=))
@@ -47,7 +49,8 @@ data FileRec = FileRec
     fileInfo :: FileInfo,
     filePath :: TVar (Maybe FilePath),
     recipientIds :: TVar (Set RecipientId),
-    createdAt :: RoundedSystemTime
+    createdAt :: RoundedSystemTime,
+    fileStatus :: TVar ServerEntityStatus
   }
 
 fileTimePrecision :: Int64
@@ -78,7 +81,8 @@ newFileRec :: SenderId -> FileInfo -> RoundedSystemTime -> STM FileRec
 newFileRec senderId fileInfo createdAt = do
   recipientIds <- newTVar S.empty
   filePath <- newTVar Nothing
-  pure FileRec {senderId, fileInfo, filePath, recipientIds, createdAt}
+  fileStatus <- newTVar EntityActive
+  pure FileRec {senderId, fileInfo, filePath, recipientIds, createdAt, fileStatus}
 
 setFilePath :: FileStore -> SenderId -> FilePath -> STM (Either XFTPErrorType ())
 setFilePath st sId fPath =
@@ -109,6 +113,14 @@ deleteFile FileStore {files, recipients, usedStorage} senderId = do
       pure $ Right ()
     _ -> pure $ Left AUTH
 
+-- this function must be called after the file is deleted from the file system
+blockFile :: FileStore -> SenderId -> BlockingInfo -> Bool -> STM (Either XFTPErrorType ())
+blockFile st@FileStore {usedStorage} senderId info deleted =
+  withFile st senderId $ \FileRec {fileInfo, fileStatus} -> do
+    when deleted $ modifyTVar' usedStorage $ subtract (fromIntegral $ size fileInfo)
+    writeTVar fileStatus $! EntityBlocked info
+    pure $ Right ()
+
 deleteRecipient :: FileStore -> RecipientId -> FileRec -> STM ()
 deleteRecipient FileStore {recipients} rId FileRec {recipientIds} = do
   TM.delete rId recipients

src/Simplex/FileTransfer/Server/StoreLog.hs

@@ -14,6 +14,7 @@ module Simplex.FileTransfer.Server.StoreLog
     logPutFile,
     logAddRecipients,
     logDeleteFile,
+    logBlockFile,
     logAckFile,
   )
 where
@@ -31,7 +32,7 @@ import qualified Data.Map.Strict as M
 import Simplex.FileTransfer.Protocol (FileInfo (..))
 import Simplex.FileTransfer.Server.Store
 import Simplex.Messaging.Encoding.String
-import Simplex.Messaging.Protocol (RcvPublicAuthKey, RecipientId, SenderId)
+import Simplex.Messaging.Protocol (BlockingInfo, RcvPublicAuthKey, RecipientId, SenderId)
 import Simplex.Messaging.Server.QueueStore (RoundedSystemTime)
 import Simplex.Messaging.Server.StoreLog
 import Simplex.Messaging.Util (bshow)
@@ -42,7 +43,8 @@ data FileStoreLogRecord
   | PutFile SenderId FilePath
   | AddRecipients SenderId (NonEmpty FileRecipient)
   | DeleteFile SenderId
-  | AckFile RecipientId
+  | BlockFile SenderId BlockingInfo
+  | AckFile RecipientId -- TODO add senderId as well?
   deriving (Show)
 
 instance StrEncoding FileStoreLogRecord where
@@ -51,6 +53,7 @@ instance StrEncoding FileStoreLogRecord where
     PutFile sId path -> strEncode (Str "FPUT", sId, path)
     AddRecipients sId rcps -> strEncode (Str "FADD", sId, rcps)
     DeleteFile sId -> strEncode (Str "FDEL", sId)
+    BlockFile sId info -> strEncode (Str "FBLK", sId, info)
     AckFile rId -> strEncode (Str "FACK", rId)
   strP =
     A.choice
@@ -58,6 +61,7 @@ instance StrEncoding FileStoreLogRecord where
         "FPUT " *> (PutFile <$> strP_ <*> strP),
         "FADD " *> (AddRecipients <$> strP_ <*> strP),
         "FDEL " *> (DeleteFile <$> strP),
+        "FBLK " *> (BlockFile <$> strP_ <*> strP),
         "FACK " *> (AckFile <$> strP)
       ]
 
@@ -76,6 +80,9 @@ logAddRecipients s = logFileStoreRecord s .: AddRecipients
 logDeleteFile :: StoreLog 'WriteMode -> SenderId -> IO ()
 logDeleteFile s = logFileStoreRecord s . DeleteFile
 
+logBlockFile :: StoreLog 'WriteMode -> SenderId -> BlockingInfo -> IO ()
+logBlockFile s fId = logFileStoreRecord s . BlockFile fId
+
 logAckFile :: StoreLog 'WriteMode -> RecipientId -> IO ()
 logAckFile s = logFileStoreRecord s . AckFile
 
@@ -96,6 +103,7 @@ readFileStore f st = mapM_ (addFileLogRecord . LB.toStrict) . LB.lines =<< LB.re
       PutFile qId path -> setFilePath st qId path
       AddRecipients sId rcps -> runExceptT $ addRecipients sId rcps
       DeleteFile sId -> deleteFile st sId
+      BlockFile sId info -> blockFile st sId info True
       AckFile rId -> ackFile st rId
     addRecipients sId rcps = mapM_ (ExceptT . addRecipient st sId) rcps
 

src/Simplex/FileTransfer/Transport.hs

@@ -11,6 +11,7 @@
 module Simplex.FileTransfer.Transport
   ( supportedFileServerVRange,
     authCmdsXFTPVersion,
+    blockedFilesXFTPVersion,
     xftpClientHandshakeStub,
     supportedXFTPhandshakes,
     XFTPClientHandshake (..),
@@ -33,7 +34,6 @@ module Simplex.FileTransfer.Transport
   )
 where
 
-import Control.Applicative ((<|>))
 import qualified Control.Exception as E
 import Control.Logger.Simple
 import Control.Monad
@@ -57,7 +57,7 @@ import qualified Simplex.Messaging.Crypto.Lazy as LC
 import Simplex.Messaging.Encoding
 import Simplex.Messaging.Encoding.String
 import Simplex.Messaging.Parsers
-import Simplex.Messaging.Protocol (CommandError)
+import Simplex.Messaging.Protocol (BlockingInfo, CommandError)
 import Simplex.Messaging.Transport (ALPN, SessionId, THandle (..), THandleParams (..), TransportError (..), TransportPeer (..))
 import Simplex.Messaging.Transport.HTTP2.File
 import Simplex.Messaging.Util (bshow, tshow)
@@ -92,8 +92,11 @@ initialXFTPVersion = VersionXFTP 1
 authCmdsXFTPVersion :: VersionXFTP
 authCmdsXFTPVersion = VersionXFTP 2
 
+blockedFilesXFTPVersion :: VersionXFTP
+blockedFilesXFTPVersion = VersionXFTP 3
+
 currentXFTPVersion :: VersionXFTP
-currentXFTPVersion = VersionXFTP 2
+currentXFTPVersion = VersionXFTP 3
 
 supportedFileServerVRange :: VersionRangeXFTP
 supportedFileServerVRange = mkVersionRange initialXFTPVersion currentXFTPVersion
@@ -211,6 +214,8 @@ data XFTPErrorType
     CMD {cmdErr :: CommandError}
   | -- | command authorization error - bad signature or non-existing SMP queue
     AUTH
+  | -- | command with the entity that was blocked
+    BLOCKED {blockInfo :: BlockingInfo}
   | -- | incorrent file size
     SIZE
   | -- | storage quota exceeded
@@ -231,15 +236,46 @@ data XFTPErrorType
     INTERNAL
   | -- | used internally, never returned by the server (to be removed)
     DUPLICATE_ -- not part of SMP protocol, used internally
-  deriving (Eq, Read, Show)
+  deriving (Eq, Show)
 
 instance StrEncoding XFTPErrorType where
   strEncode = \case
+    BLOCK -> "BLOCK"
+    SESSION -> "SESSION"
+    HANDSHAKE -> "HANDSHAKE"
     CMD e -> "CMD " <> bshow e
-    e -> bshow e
+    AUTH -> "AUTH"
+    BLOCKED info -> "BLOCKED " <> strEncode info
+    SIZE -> "SIZE"
+    QUOTA -> "QUOTA"
+    DIGEST -> "DIGEST"
+    CRYPTO -> "CRYPTO"
+    NO_FILE -> "NO_FILE"
+    HAS_FILE -> "HAS_FILE"
+    FILE_IO -> "FILE_IO"
+    TIMEOUT -> "TIMEOUT"
+    INTERNAL -> "INTERNAL"
+    DUPLICATE_ -> "DUPLICATE_"
+
   strP =
-    "CMD " *> (CMD <$> parseRead1)
-      <|> parseRead1
+    A.takeTill (== ' ') >>= \case
+      "BLOCK" -> pure BLOCK
+      "SESSION" -> pure SESSION
+      "HANDSHAKE" -> pure HANDSHAKE
+      "CMD" -> CMD <$> parseRead1
+      "AUTH" -> pure AUTH
+      "BLOCKED" -> BLOCKED <$> _strP
+      "SIZE" -> pure SIZE
+      "QUOTA" -> pure QUOTA
+      "DIGEST" -> pure DIGEST
+      "CRYPTO" -> pure CRYPTO
+      "NO_FILE" -> pure NO_FILE
+      "HAS_FILE" -> pure HAS_FILE
+      "FILE_IO" -> pure FILE_IO
+      "TIMEOUT" -> pure TIMEOUT
+      "INTERNAL" -> pure INTERNAL
+      "DUPLICATE_" -> pure DUPLICATE_
+      _ -> fail "bad error type"
 
 instance Encoding XFTPErrorType where
   smpEncode = \case
@@ -248,6 +284,7 @@ instance Encoding XFTPErrorType where
     HANDSHAKE -> "HANDSHAKE"
     CMD err -> "CMD " <> smpEncode err
     AUTH -> "AUTH"
+    BLOCKED info -> "BLOCKED " <> smpEncode info
     SIZE -> "SIZE"
     QUOTA -> "QUOTA"
     DIGEST -> "DIGEST"
@@ -266,6 +303,7 @@ instance Encoding XFTPErrorType where
       "HANDSHAKE" -> pure HANDSHAKE
       "CMD" -> CMD <$> _smpP
       "AUTH" -> pure AUTH
+      "BLOCKED" -> BLOCKED <$> _smpP
       "SIZE" -> pure SIZE
       "QUOTA" -> pure QUOTA
       "DIGEST" -> pure DIGEST