src/client.rs

@@ -175,7 +175,7 @@ impl ClientConn {
 				"Too many inflight requests! RequestID collision. Interrupting previous request."
 			);
 			let _ = old_ch.send(Box::pin(futures::stream::once(async move {
-				Err(Error::IdCollision.code())
+				Err(std::io::Error::new(std::io::ErrorKind::Other, "RequestID collision, too many inflight requests"))
 			})));
 		}
 

src/recv.rs

@@ -35,7 +35,7 @@ impl Sender {
 impl Drop for Sender {
 	fn drop(&mut self) {
 		if let Some(inner) = self.inner.take() {
-			let _ = inner.send(Err(255));
+			let _ = inner.send(Err(std::io::Error::new(std::io::ErrorKind::BrokenPipe, "Netapp connection dropped before end of stream")));
 		}
 	}
 }
@@ -76,25 +76,26 @@ pub(crate) trait RecvLoop: Sync + 'static {
 
 			let has_cont = (size & CHUNK_HAS_CONTINUATION) != 0;
 			let is_error = (size & ERROR_MARKER) != 0;
-			let packet = if is_error {
-				trace!(
-					"recv_loop: got id {}, header_size {:04x}, error {}",
-					id,
-					size,
-					size & !ERROR_MARKER
-				);
-				Err((size & !ERROR_MARKER) as u8)
-			} else {
-				let size = size & !CHUNK_HAS_CONTINUATION;
+			let size = (size & CHUNK_LENGTH_MASK) as usize;
 			let mut next_slice = vec![0; size as usize];
 			read.read_exact(&mut next_slice[..]).await?;
+
+			let packet = if is_error {
+				let msg = String::from_utf8(next_slice).unwrap_or("<invalid utf8 error message>".into());
+				debug!("recv_loop: got id {}, error: {}", id, msg);
+				Some(Err(std::io::Error::new(std::io::ErrorKind::Other, msg)))
+			} else {
 				trace!(
-					"recv_loop: got id {}, header_size {:04x}, {} bytes",
+					"recv_loop: got id {}, size {}, has_cont {}",
 					id,
 					size,
-					next_slice.len()
+					has_cont
 				);
-				Ok(Bytes::from(next_slice))
+				if !next_slice.is_empty() {
+					Some(Ok(Bytes::from(next_slice)))
+				} else {
+					None
+				}
 			};
 
 			let mut sender = if let Some(send) = streams.remove(&(id)) {
@@ -109,9 +110,12 @@ pub(crate) trait RecvLoop: Sync + 'static {
 				Sender::new(send)
 			};
 
-			// If we get an error, the receiving end is disconnected.
+			if let Some(packet) = packet {
+				// If we cannot put packet in channel, it means that the
+				// receiving end of the channel is disconnected.
 				// We still need to reach eos before dropping this sender
 				let _ = sender.send(packet);
+			}
 
 			if has_cont {
 				assert!(!is_error);

src/send.rs

@@ -18,9 +18,11 @@ use crate::stream::*;
 // Messages are sent by chunks
 // Chunk format:
 // - u32 BE: request id (same for request and response)
-// - u16 BE: chunk length, possibly with CHUNK_HAS_CONTINUATION flag
-//					when this is not the last chunk of the message
-// - [u8; chunk_length] chunk data
+// - u16 BE: chunk length + flags:
+//		CHUNK_HAS_CONTINUATION when this is not the last chunk of the stream
+//		ERROR_MARKER if this chunk denotes an error
+//		(these two flags are exclusive, an error denotes the end of the stream)
+// - [u8; chunk_length] chunk data / error message
 
 pub(crate) type RequestID = u32;
 pub(crate) type ChunkLength = u16;
@@ -28,6 +30,7 @@ pub(crate) type ChunkLength = u16;
 pub(crate) const MAX_CHUNK_LENGTH: ChunkLength = 0x3FF0;
 pub(crate) const ERROR_MARKER: ChunkLength = 0x4000;
 pub(crate) const CHUNK_HAS_CONTINUATION: ChunkLength = 0x8000;
+pub(crate) const CHUNK_LENGTH_MASK: ChunkLength = 0x3FFF;
 
 struct SendQueue {
 	items: Vec<(u8, VecDeque<SendQueueItem>)>,
@@ -92,29 +95,12 @@ impl<'a> futures::Future for SendQueuePollNextReady<'a> {
 				let id = item.id;
 				let eos = item.data.eos();
 
-				let data_frame = match bytes_or_err {
-					Ok(bytes) => {
-						trace!(
-							"send queue poll next ready: id {} eos {:?} bytes {}",
-							id,
-							eos,
-							bytes.len()
-						);
-						DataFrame::Data(bytes, !eos)
-					}
-					Err(e) => DataFrame::Error(match e {
-						ReadExactError::Stream(code) => {
-							trace!(
-								"send queue poll next ready: id {} eos {:?} ERROR {}",
-								id,
-								eos,
-								code
-							);
-							code
-						}
+				let packet = bytes_or_err.map_err(|e| match e {
+					ReadExactError::Stream(err) => err,
 					_ => unreachable!(),
-					}),
-				};
+				});
+
+				let data_frame = DataFrame::from_packet(packet, !eos);
 
 				if !eos && !matches!(data_frame, DataFrame::Error(_)) {
 					items_at_prio.push_back(item);
@@ -139,15 +125,32 @@ enum DataFrame {
 	/// (albeit sub-optimal) to set it to true if there is nothing coming after
 	Data(Bytes, bool),
 	/// An error code automatically signals the end of the stream
-	Error(u8),
+	Error(Bytes),
 }
 
 impl DataFrame {
+	fn from_packet(p: Packet, has_cont: bool) -> Self {
+		match p {
+			Ok(bytes) => {
+				assert!(bytes.len() <= MAX_CHUNK_LENGTH as usize);
+				Self::Data(bytes, has_cont)
+			}
+			Err(e) => {
+				let msg = format!("{}", e);
+				let mut msg = Bytes::from(msg.into_bytes());
+				if msg.len() > MAX_CHUNK_LENGTH as usize {
+					msg = msg.slice(..MAX_CHUNK_LENGTH as usize);
+				}
+				Self::Error(msg)
+			}
+		}
+	}
+
 	fn header(&self) -> [u8; 2] {
 		let header_u16 = match self {
 			DataFrame::Data(data, false) => data.len() as u16,
 			DataFrame::Data(data, true) => data.len() as u16 | CHUNK_HAS_CONTINUATION,
-			DataFrame::Error(e) => *e as u16 | ERROR_MARKER,
+			DataFrame::Error(msg) => msg.len() as u16 | ERROR_MARKER,
 		};
 		ChunkLength::to_be_bytes(header_u16)
 	}
@@ -155,7 +158,7 @@ impl DataFrame {
 	fn data(&self) -> &[u8] {
 		match self {
 			DataFrame::Data(ref data, _) => &data[..],
-			DataFrame::Error(_) => &[],
+			DataFrame::Error(ref msg) => &msg[..],
 		}
 	}
 }

src/stream.rs

@@ -4,7 +4,7 @@ use std::task::{Context, Poll};
 use bytes::Bytes;
 
 use futures::Future;
-use futures::{Stream, StreamExt, TryStreamExt};
+use futures::{Stream, StreamExt};
 use tokio::io::AsyncRead;
 
 use crate::bytes_buf::BytesBuf;
@@ -18,7 +18,7 @@ use crate::bytes_buf::BytesBuf;
 /// meaning, it's up to your application to define their semantic.
 pub type ByteStream = Pin<Box<dyn Stream<Item = Packet> + Send + Sync>>;
 
-pub type Packet = Result<Bytes, u8>;
+pub type Packet = Result<Bytes, std::io::Error>;
 
 // ----
 
@@ -26,7 +26,7 @@ pub struct ByteStreamReader {
 	stream: ByteStream,
 	buf: BytesBuf,
 	eos: bool,
-	err: Option<u8>,
+	err: Option<std::io::Error>,
 }
 
 impl ByteStreamReader {
@@ -99,7 +99,7 @@ impl ByteStreamReader {
 
 pub enum ReadExactError {
 	UnexpectedEos,
-	Stream(u8),
+	Stream(std::io::Error),
 }
 
 #[pin_project::pin_project]
@@ -120,7 +120,8 @@ impl<'a> Future for ByteStreamReadExact<'a> {
 			if let Some(bytes) = this.reader.try_get(*this.read_len) {
 				return Poll::Ready(Ok(bytes));
 			}
-			if let Some(err) = this.reader.err {
+			if let Some(err) = &this.reader.err {
+				let err = std::io::Error::new(err.kind(), format!("{}", err));
 				return Poll::Ready(Err(ReadExactError::Stream(err)));
 			}
 			if this.reader.eos {
@@ -149,6 +150,7 @@ impl<'a> Future for ByteStreamReadExact<'a> {
 
 // ----
 
+/*
 fn u8_to_io_error(v: u8) -> std::io::Error {
 	use std::io::{Error, ErrorKind};
 	let kind = match v {
@@ -183,11 +185,12 @@ fn io_error_to_u8(e: std::io::Error) -> u8 {
 		_ => 100,
 	}
 }
+*/
 
 pub fn asyncread_stream<R: AsyncRead + Send + Sync + 'static>(reader: R) -> ByteStream {
-	Box::pin(tokio_util::io::ReaderStream::new(reader).map_err(io_error_to_u8))
+	Box::pin(tokio_util::io::ReaderStream::new(reader))
 }
 
 pub fn stream_asyncread(stream: ByteStream) -> impl AsyncRead + Send + Sync + 'static {
-	tokio_util::io::StreamReader::new(stream.map_err(u8_to_io_error))
+	tokio_util::io::StreamReader::new(stream)
 }