xftp: force single chunk for redirect descriptions (#1050)

* xftp: force single chunk for redirect descriptions

* Update src/Simplex/FileTransfer/Client/Main.hs

Co-authored-by: spaced4ndy <8711996+spaced4ndy@users.noreply.github.com>

---------

Co-authored-by: spaced4ndy <8711996+spaced4ndy@users.noreply.github.com>

src/Simplex/FileTransfer/Agent.hs

@@ -389,16 +389,20 @@ runXFTPSndPrepareWorker c Worker {doWork} = do
       where
         AgentConfig {xftpMaxRecipientsPerRequest = maxRecipients, messageRetryInterval = ri} = cfg
         encryptFileForUpload :: SndFile -> FilePath -> m (FileDigest, [(XFTPChunkSpec, FileDigest)])
-        encryptFileForUpload SndFile {key, nonce, srcFile} fsEncPath = do
+        encryptFileForUpload SndFile {key, nonce, srcFile, redirect} fsEncPath = do
           let CryptoFile {filePath} = srcFile
               fileName = takeFileName filePath
           fileSize <- liftIO $ fromInteger <$> CF.getFileContentsSize srcFile
           when (fileSize > maxFileSizeHard) $ throwError $ INTERNAL "max file size exceeded"
           let fileHdr = smpEncode FileHeader {fileName, fileExtra = Nothing}
               fileSize' = fromIntegral (B.length fileHdr) + fileSize
-              chunkSizes = prepareChunkSizes $ fileSize' + fileSizeLen + authTagSize
-              chunkSizes' = map fromIntegral chunkSizes
-              encSize = sum chunkSizes'
+              payloadSize = fileSize' + fileSizeLen + authTagSize
+          chunkSizes <- case redirect of
+            Nothing -> pure $ prepareChunkSizes payloadSize
+            Just _ -> case singleChunkSize payloadSize of
+              Nothing -> throwError $ INTERNAL "max file size exceeded for redirect"
+              Just chunkSize -> pure [chunkSize]
+          let encSize = sum $ map fromIntegral chunkSizes
           void $ liftError (INTERNAL . show) $ encryptFile srcFile fileHdr key nonce fileSize' encSize fsEncPath
           digest <- liftIO $ LC.sha512Hash <$> LB.readFile fsEncPath
           let chunkSpecs = prepareChunkSpecs fsEncPath chunkSizes

src/Simplex/FileTransfer/Client/Main.hs

@@ -16,6 +16,7 @@ module Simplex.FileTransfer.Client.Main
     xftpClientCLI,
     cliSendFile,
     cliSendFileOpts,
+    singleChunkSize,
     prepareChunkSizes,
     prepareChunkSpecs,
     maxFileSize,
@@ -42,7 +43,7 @@ import Data.List.NonEmpty (NonEmpty (..), nonEmpty)
 import qualified Data.List.NonEmpty as L
 import Data.Map (Map)
 import qualified Data.Map as M
-import Data.Maybe (fromMaybe)
+import Data.Maybe (fromMaybe, listToMaybe)
 import qualified Data.Text as T
 import Data.Word (Word32)
 import GHC.Records (HasField (getField))
@@ -528,6 +529,12 @@ getFileDescription' path =
   getFileDescription path >>= \case
     AVFD fd -> either (throwError . CLIError) pure $ checkParty fd
 
+singleChunkSize :: Int64 -> Maybe Word32
+singleChunkSize size' =
+  listToMaybe $ dropWhile (< chunkSize) serverChunkSizes
+  where
+    chunkSize = fromIntegral size'
+
 prepareChunkSizes :: Int64 -> [Word32]
 prepareChunkSizes size' = prepareSizes size'
   where