YamuxStream is tagged to Unreadable too early, since there may be data that hasn't been processed #167

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1. creativeid00 commented on Nov 3, 2021

   

   creativeid00

   on Nov 3, 2021

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   I would say that it is more like the stream acceptance callback is called too late.
   I got the same issue during bitswap message receiving from a remote go-ipfs peer. The go-ipfs peers sends 3 frames:

   1. frame.type WINDOW_UPDATE (1 '\x1')
      frame.length 0
      frame.flags 1
   2. frame.type DATA (0 '\0')
      frame.length 248
      frame.flags 0
   3. frame.type WINDOW_UPDATE (1 '\x1')
      frame.length 0
      frame.flags 4
      The last frame contains FIN flag that leads to onFINReceived call. Protocol handler is not called neither after the 1st frame nor after the second one. It is called when the last frame received, some response sent to the remote ipfs peer and Multiselect instance is closed. By that time the yamux stream has already been tagged as Unreadable.
2. creativeid00 commented on Nov 3, 2021

   

   creativeid00

   on Nov 3, 2021

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   Detailed investigation has shown that YamuxStream::doRead returns corresponding error

   cpp-libp2p/src/muxer/yamux/yamux_stream.cpp

   Line 447 in 91d58f2

   return deferReadCallback(Error::STREAM_NOT_READABLE, std::move(read_cb_));

   only when no pending data is available in the internal_read_buffer_.

   cpp-libp2p/src/muxer/yamux/yamux_stream.cpp

   Line 425 in 91d58f2

   if (bytes_available_now >= bytes || (some && bytes_available_now > 0)) {

   
   I'm not sure what is a semantics of YamuxStream::isClosedForRead method but it looks like the size of pending data should be checked within the method also.
3. dhuseby

   added

   help wantedExtra attention is neededExtra attention is needed

   on Oct 3, 2024