Initial moq-transport-01 support (#115)

Co-authored-by: Mike English <mike.english@gmail.com>

Cargo.lock

@@ -1107,6 +1107,7 @@ dependencies = [
 name = "moq-transport"
 version = "0.2.0"
 dependencies = [
+ "async-trait",
  "bytes",
  "indexmap 2.0.0",
  "log",

moq-pub/src/media.rs

@@ -1,6 +1,6 @@
 use crate::cli::Config;
 use anyhow::{self, Context};
-use moq_transport::cache::{broadcast, segment, track};
+use moq_transport::cache::{broadcast, fragment, segment, track};
 use moq_transport::VarInt;
 use mp4::{self, ReadBox};
 use serde_json::json;
@@ -44,11 +44,17 @@ impl Media {
 		let mut init_track = broadcast.create_track("0.mp4")?;
 		let mut init_segment = init_track.create_segment(segment::Info {
 			sequence: VarInt::ZERO,
-			priority: i32::MAX,
+			priority: 0,
 			expires: None,
 		})?;
 
-		init_segment.write_chunk(init.into())?;
+		// Create a single fragment, optionally setting the size
+		let mut init_fragment = init_segment.create_fragment(fragment::Info {
+			sequence: VarInt::ZERO,
+			size: None, // size is only needed when we have multiple fragments.
+		})?;
+
+		init_fragment.write_chunk(init.into())?;
 
 		let mut tracks = HashMap::new();
 
@@ -128,7 +134,7 @@ impl Media {
 	) -> Result<(), anyhow::Error> {
 		let mut segment = track.create_segment(segment::Info {
 			sequence: VarInt::ZERO,
-			priority: i32::MAX,
+			priority: 0,
 			expires: None,
 		})?;
 
@@ -211,8 +217,14 @@ impl Media {
 		let catalog_str = serde_json::to_string_pretty(&catalog)?;
 		log::info!("catalog: {}", catalog_str);
 
+		// Create a single fragment for the segment.
+		let mut fragment = segment.create_fragment(fragment::Info {
+			sequence: VarInt::ZERO,
+			size: None, // Size is only needed when we have multiple fragments.
+		})?;
+
 		// Add the segment and add the fragment.
-		segment.write_chunk(catalog_str.into())?;
+		fragment.write_chunk(catalog_str.into())?;
 
 		Ok(())
 	}
@@ -260,7 +272,7 @@ struct Track {
 	track: track::Publisher,
 
 	// The current segment
-	segment: Option<segment::Publisher>,
+	current: Option<fragment::Publisher>,
 
 	// The number of units per second.
 	timescale: u64,
@@ -274,16 +286,16 @@ impl Track {
 		Self {
 			track,
 			sequence: 0,
-			segment: None,
+			current: None,
 			timescale,
 		}
 	}
 
 	pub fn header(&mut self, raw: Vec<u8>, fragment: Fragment) -> anyhow::Result<()> {
-		if let Some(segment) = self.segment.as_mut() {
+		if let Some(current) = self.current.as_mut() {
 			if !fragment.keyframe {
 				// Use the existing segment
-				segment.write_chunk(raw.into())?;
+				current.write_chunk(raw.into())?;
 				return Ok(());
 			}
 		}
@@ -292,7 +304,7 @@ impl Track {
 
 		// Compute the timestamp in milliseconds.
 		// Overflows after 583 million years, so we're fine.
-		let timestamp: i32 = fragment
+		let timestamp: u32 = fragment
 			.timestamp(self.timescale)
 			.as_millis()
 			.try_into()
@@ -301,26 +313,34 @@ impl Track {
 		// Create a new segment.
 		let mut segment = self.track.create_segment(segment::Info {
 			sequence: VarInt::try_from(self.sequence).context("sequence too large")?,
-			priority: timestamp, // newer segments are higher priority
+
+			// Newer segments are higher priority
+			priority: u32::MAX.checked_sub(timestamp).context("priority too large")?,
 
 			// Delete segments after 10s.
 			expires: Some(time::Duration::from_secs(10)),
 		})?;
 
+		// Create a single fragment for the segment that we will keep appending.
+		let mut fragment = segment.create_fragment(fragment::Info {
+			sequence: VarInt::ZERO,
+			size: None,
+		})?;
+
 		self.sequence += 1;
 
 		// Insert the raw atom into the segment.
-		segment.write_chunk(raw.into())?;
+		fragment.write_chunk(raw.into())?;
 
 		// Save for the next iteration
-		self.segment = Some(segment);
+		self.current = Some(fragment);
 
 		Ok(())
 	}
 
 	pub fn data(&mut self, raw: Vec<u8>) -> anyhow::Result<()> {
-		let segment = self.segment.as_mut().context("missing segment")?;
+		let fragment = self.current.as_mut().context("missing current fragment")?;
-		segment.write_chunk(raw.into())?;
+		fragment.write_chunk(raw.into())?;
 
 		Ok(())
 	}

moq-relay/src/error.rs

@@ -37,15 +37,15 @@ impl moq_transport::MoqError for RelayError {
 		}
 	}
 
-	fn reason(&self) -> &str {
+	fn reason(&self) -> String {
 		match self {
-			Self::Transport(err) => err.reason(),
+			Self::Transport(err) => format!("transport error: {}", err.reason()),
-			Self::Cache(err) => err.reason(),
+			Self::Cache(err) => format!("cache error: {}", err.reason()),
-			Self::MoqApi(_err) => "api error",
+			Self::MoqApi(err) => format!("api error: {}", err),
-			Self::Url(_) => "url error",
+			Self::Url(err) => format!("url error: {}", err),
-			Self::MissingNode => "missing node",
+			Self::MissingNode => "missing node".to_owned(),
-			Self::WebTransportServer(_) => "server error",
+			Self::WebTransportServer(err) => format!("upstream server error: {}", err),
-			Self::WebTransportClient(_) => "upstream error",
+			Self::WebTransportClient(err) => format!("upstream client error: {}", err),
 		}
 	}
 }

moq-transport/Cargo.toml

@@ -24,3 +24,5 @@ indexmap = "2"
 quinn = "0.10"
 webtransport-quinn = "0.6"
 #webtransport-quinn = { path = "../../webtransport-rs/webtransport-quinn" }
+
+async-trait = "0.1"

moq-transport/src/cache/broadcast.rs

@@ -136,12 +136,12 @@ impl Publisher {
 	}
 
 	/// Block until the next track requested by a subscriber.
-	pub async fn next_track(&mut self) -> Result<Option<track::Publisher>, CacheError> {
+	pub async fn next_track(&mut self) -> Result<track::Publisher, CacheError> {
 		loop {
 			let notify = {
 				let state = self.state.lock();
 				if state.has_next()? {
-					return Ok(Some(state.into_mut().next()));
+					return Ok(state.into_mut().next());
 				}
 
 				state.changed()

moq-transport/src/cache/error.rs

@@ -39,13 +39,13 @@ impl MoqError for CacheError {
 	}
 
 	/// A reason that is sent over the wire.
-	fn reason(&self) -> &str {
+	fn reason(&self) -> String {
 		match self {
-			Self::Closed => "closed",
+			Self::Closed => "closed".to_owned(),
-			Self::Reset(_) => "reset",
+			Self::Reset(code) => format!("reset code: {}", code),
-			Self::Stop => "stop",
+			Self::Stop => "stop".to_owned(),
-			Self::NotFound => "not found",
+			Self::NotFound => "not found".to_owned(),
-			Self::Duplicate => "duplicate",
+			Self::Duplicate => "duplicate".to_owned(),
 		}
 	}
 }

moq-transport/src/cache/fragment.rs

@@ -0,0 +1,216 @@
+//! A fragment is a stream of bytes with a header, split into a [Publisher] and [Subscriber] handle.
+//!
+//! A [Publisher] writes an ordered stream of bytes in chunks.
+//! There's no framing, so these chunks can be of any size or position, and won't be maintained over the network.
+//!
+//! A [Subscriber] reads an ordered stream of bytes in chunks.
+//! These chunks are returned directly from the QUIC connection, so they may be of any size or position.
+//! You can clone the [Subscriber] and each will read a copy of of all future chunks. (fanout)
+//!
+//! The fragment is closed with [CacheError::Closed] when all publishers or subscribers are dropped.
+use core::fmt;
+use std::{ops::Deref, sync::Arc};
+
+use crate::VarInt;
+use bytes::Bytes;
+
+use super::{CacheError, Watch};
+
+/// Create a new segment with the given info.
+pub fn new(info: Info) -> (Publisher, Subscriber) {
+	let state = Watch::new(State::default());
+	let info = Arc::new(info);
+
+	let publisher = Publisher::new(state.clone(), info.clone());
+	let subscriber = Subscriber::new(state, info);
+
+	(publisher, subscriber)
+}
+
+/// Static information about the segment.
+#[derive(Debug)]
+pub struct Info {
+	// The sequence number of the fragment within the segment.
+	// NOTE: These may be received out of order or with gaps.
+	pub sequence: VarInt,
+
+	// The size of the fragment, optionally None if this is the last fragment in a segment.
+	// TODO enforce this size.
+	pub size: Option<VarInt>,
+}
+
+struct State {
+	// The data that has been received thus far.
+	chunks: Vec<Bytes>,
+
+	// Set when the publisher is dropped.
+	closed: Result<(), CacheError>,
+}
+
+impl State {
+	pub fn close(&mut self, err: CacheError) -> Result<(), CacheError> {
+		self.closed.clone()?;
+		self.closed = Err(err);
+		Ok(())
+	}
+
+	pub fn bytes(&self) -> usize {
+		self.chunks.iter().map(|f| f.len()).sum::<usize>()
+	}
+}
+
+impl Default for State {
+	fn default() -> Self {
+		Self {
+			chunks: Vec::new(),
+			closed: Ok(()),
+		}
+	}
+}
+
+impl fmt::Debug for State {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		// We don't want to print out the contents, so summarize.
+		f.debug_struct("State")
+			.field("chunks", &self.chunks.len().to_string())
+			.field("bytes", &self.bytes().to_string())
+			.field("closed", &self.closed)
+			.finish()
+	}
+}
+
+/// Used to write data to a segment and notify subscribers.
+pub struct Publisher {
+	// Mutable segment state.
+	state: Watch<State>,
+
+	// Immutable segment state.
+	info: Arc<Info>,
+
+	// Closes the segment when all Publishers are dropped.
+	_dropped: Arc<Dropped>,
+}
+
+impl Publisher {
+	fn new(state: Watch<State>, info: Arc<Info>) -> Self {
+		let _dropped = Arc::new(Dropped::new(state.clone()));
+		Self { state, info, _dropped }
+	}
+
+	/// Write a new chunk of bytes.
+	pub fn write_chunk(&mut self, chunk: Bytes) -> Result<(), CacheError> {
+		let mut state = self.state.lock_mut();
+		state.closed.clone()?;
+		state.chunks.push(chunk);
+		Ok(())
+	}
+
+	/// Close the segment with an error.
+	pub fn close(self, err: CacheError) -> Result<(), CacheError> {
+		self.state.lock_mut().close(err)
+	}
+}
+
+impl Deref for Publisher {
+	type Target = Info;
+
+	fn deref(&self) -> &Self::Target {
+		&self.info
+	}
+}
+
+impl fmt::Debug for Publisher {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		f.debug_struct("Publisher")
+			.field("state", &self.state)
+			.field("info", &self.info)
+			.finish()
+	}
+}
+
+/// Notified when a segment has new data available.
+#[derive(Clone)]
+pub struct Subscriber {
+	// Modify the segment state.
+	state: Watch<State>,
+
+	// Immutable segment state.
+	info: Arc<Info>,
+
+	// The number of chunks that we've read.
+	// NOTE: Cloned subscribers inherit this index, but then run in parallel.
+	index: usize,
+
+	// Dropped when all Subscribers are dropped.
+	_dropped: Arc<Dropped>,
+}
+
+impl Subscriber {
+	fn new(state: Watch<State>, info: Arc<Info>) -> Self {
+		let _dropped = Arc::new(Dropped::new(state.clone()));
+
+		Self {
+			state,
+			info,
+			index: 0,
+			_dropped,
+		}
+	}
+
+	/// Block until the next chunk of bytes is available.
+	pub async fn read_chunk(&mut self) -> Result<Option<Bytes>, CacheError> {
+		loop {
+			let notify = {
+				let state = self.state.lock();
+				if self.index < state.chunks.len() {
+					let chunk = state.chunks[self.index].clone();
+					self.index += 1;
+					return Ok(Some(chunk));
+				}
+
+				match &state.closed {
+					Err(CacheError::Closed) => return Ok(None),
+					Err(err) => return Err(err.clone()),
+					Ok(()) => state.changed(),
+				}
+			};
+
+			notify.await; // Try again when the state changes
+		}
+	}
+}
+
+impl Deref for Subscriber {
+	type Target = Info;
+
+	fn deref(&self) -> &Self::Target {
+		&self.info
+	}
+}
+
+impl fmt::Debug for Subscriber {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		f.debug_struct("Subscriber")
+			.field("state", &self.state)
+			.field("info", &self.info)
+			.field("index", &self.index)
+			.finish()
+	}
+}
+
+struct Dropped {
+	// Modify the segment state.
+	state: Watch<State>,
+}
+
+impl Dropped {
+	fn new(state: Watch<State>) -> Self {
+		Self { state }
+	}
+}
+
+impl Drop for Dropped {
+	fn drop(&mut self) {
+		self.state.lock_mut().close(CacheError::Closed).ok();
+	}
+}

moq-transport/src/cache/mod.rs

@@ -1,10 +1,17 @@
 //! Allows a publisher to push updates, automatically caching and fanning it out to any subscribers.
 //!
-//! The naming scheme doesn't match the spec because it's vague and confusing.
+//! The hierarchy is: [broadcast] -> [track] -> [segment] -> [fragment] -> [Bytes](bytes::Bytes)
-//! The hierarchy is: [broadcast] -> [track] -> [segment] -> [Bytes](bytes::Bytes)
+//!
+//! The naming scheme doesn't match the spec because it's more strict, and bikeshedding of course:
+//!
+//! - [broadcast] is kinda like "track namespace"
+//! - [track] is "track"
+//! - [segment] is "group" but MUST use a single stream.
+//! - [fragment] is "object" but MUST have the same properties as the segment.
 
 pub mod broadcast;
 mod error;
+pub mod fragment;
 pub mod segment;
 pub mod track;
 

moq-transport/src/cache/segment.rs

@@ -1,20 +1,18 @@
-//! A segment is a stream of bytes with a header, split into a [Publisher] and [Subscriber] handle.
+//! A segment is a stream of fragments with a header, split into a [Publisher] and [Subscriber] handle.
 //!
-//! A [Publisher] writes an ordered stream of bytes in chunks.
+//! A [Publisher] writes an ordered stream of fragments.
-//! There's no framing, so these chunks can be of any size or position, and won't be maintained over the network.
+//! Each fragment can have a sequence number, allowing the subscriber to detect gaps fragments.
 //!
-//! A [Subscriber] reads an ordered stream of bytes in chunks.
+//! A [Subscriber] reads an ordered stream of fragments.
-//! These chunks are returned directly from the QUIC connection, so they may be of any size or position.
+//! The subscriber can be cloned, in which case each subscriber receives a copy of each fragment. (fanout)
-//! A closed [Subscriber] will receive a copy of all future chunks. (fanout)
 //!
 //! The segment is closed with [CacheError::Closed] when all publishers or subscribers are dropped.
 use core::fmt;
 use std::{ops::Deref, sync::Arc, time};
 
 use crate::VarInt;
-use bytes::Bytes;
 
-use super::{CacheError, Watch};
+use super::{fragment, CacheError, Watch};
 
 /// Create a new segment with the given info.
 pub fn new(info: Info) -> (Publisher, Subscriber) {
@@ -31,10 +29,11 @@ pub fn new(info: Info) -> (Publisher, Subscriber) {
 #[derive(Debug)]
 pub struct Info {
 	// The sequence number of the segment within the track.
+	// NOTE: These may be received out of order or with gaps.
 	pub sequence: VarInt,
 
 	// The priority of the segment within the BROADCAST.
-	pub priority: i32,
+	pub priority: u32,
 
 	// Cache the segment for at most this long.
 	pub expires: Option<time::Duration>,
@@ -42,7 +41,7 @@ pub struct Info {
 
 struct State {
 	// The data that has been received thus far.
-	data: Vec<Bytes>,
+	fragments: Vec<fragment::Subscriber>,
 
 	// Set when the publisher is dropped.
 	closed: Result<(), CacheError>,
@@ -59,7 +58,7 @@ impl State {
 impl Default for State {
 	fn default() -> Self {
 		Self {
-			data: Vec::new(),
+			fragments: Vec::new(),
 			closed: Ok(()),
 		}
 	}
@@ -67,12 +66,8 @@ impl Default for State {
 
 impl fmt::Debug for State {
 	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-		// We don't want to print out the contents, so summarize.
-		let size = self.data.iter().map(|chunk| chunk.len()).sum::<usize>();
-		let data = format!("size={} chunks={}", size, self.data.len());
-
 		f.debug_struct("State")
-			.field("data", &data)
+			.field("fragments", &self.fragments)
 			.field("closed", &self.closed)
 			.finish()
 	}
@@ -96,14 +91,20 @@ impl Publisher {
 		Self { state, info, _dropped }
 	}
 
-	/// Write a new chunk of bytes.
+	/// Write a fragment
-	pub fn write_chunk(&mut self, data: Bytes) -> Result<(), CacheError> {
+	pub fn push_fragment(&mut self, fragment: fragment::Subscriber) -> Result<(), CacheError> {
 		let mut state = self.state.lock_mut();
 		state.closed.clone()?;
-		state.data.push(data);
+		state.fragments.push(fragment);
 		Ok(())
 	}
 
+	pub fn create_fragment(&mut self, fragment: fragment::Info) -> Result<fragment::Publisher, CacheError> {
+		let (publisher, subscriber) = fragment::new(fragment);
+		self.push_fragment(subscriber)?;
+		Ok(publisher)
+	}
+
 	/// Close the segment with an error.
 	pub fn close(self, err: CacheError) -> Result<(), CacheError> {
 		self.state.lock_mut().close(err)
@@ -157,14 +158,14 @@ impl Subscriber {
 	}
 
 	/// Block until the next chunk of bytes is available.
-	pub async fn read_chunk(&mut self) -> Result<Option<Bytes>, CacheError> {
+	pub async fn next_fragment(&mut self) -> Result<Option<fragment::Subscriber>, CacheError> {
 		loop {
 			let notify = {
 				let state = self.state.lock();
-				if self.index < state.data.len() {
+				if self.index < state.fragments.len() {
-					let chunk = state.data[self.index].clone();
+					let fragment = state.fragments[self.index].clone();
 					self.index += 1;
-					return Ok(Some(chunk));
+					return Ok(Some(fragment));
 				}
 
 				match &state.closed {

moq-transport/src/cache/track.rs

@@ -206,7 +206,7 @@ impl Subscriber {
 		}
 	}
 
-	/// Block until the next segment arrives, or return None if the track is [CacheError::Closed].
+	/// Block until the next segment arrives
 	pub async fn next_segment(&mut self) -> Result<Option<segment::Subscriber>, CacheError> {
 		loop {
 			let notify = {

moq-transport/src/coding/decode.rs

@@ -1,5 +1,5 @@
 use super::{BoundsExceeded, VarInt};
-use std::str;
+use std::{io, str};
 
 use thiserror::Error;
 
@@ -7,6 +7,13 @@ use thiserror::Error;
 // TODO Use trait aliases when they're stable, or add these bounds to every method.
 pub trait AsyncRead: tokio::io::AsyncRead + Unpin + Send {}
 impl AsyncRead for webtransport_quinn::RecvStream {}
+impl<T> AsyncRead for tokio::io::Take<&mut T> where T: AsyncRead {}
+impl<T: AsRef<[u8]> + Unpin + Send> AsyncRead for io::Cursor<T> {}
+
+#[async_trait::async_trait]
+pub trait Decode: Sized {
+	async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError>;
+}
 
 /// A decode error.
 #[derive(Error, Debug)]
@@ -17,12 +24,32 @@ pub enum DecodeError {
 	#[error("invalid string")]
 	InvalidString(#[from] str::Utf8Error),
 
-	#[error("invalid type: {0:?}")]
+	#[error("invalid message: {0:?}")]
-	InvalidType(VarInt),
+	InvalidMessage(VarInt),
+
+	#[error("invalid role: {0:?}")]
+	InvalidRole(VarInt),
+
+	#[error("invalid subscribe location")]
+	InvalidSubscribeLocation,
 
 	#[error("varint bounds exceeded")]
 	BoundsExceeded(#[from] BoundsExceeded),
 
+	// TODO move these to ParamError
+	#[error("duplicate parameter")]
+	DupliateParameter,
+
+	#[error("missing parameter")]
+	MissingParameter,
+
+	#[error("invalid parameter")]
+	InvalidParameter,
+
 	#[error("io error: {0}")]
 	IoError(#[from] std::io::Error),
+
+	// Used to signal that the stream has ended.
+	#[error("no more messages")]
+	Final,
 }

moq-transport/src/coding/encode.rs

@@ -6,6 +6,12 @@ use thiserror::Error;
 // TODO Use trait aliases when they're stable, or add these bounds to every method.
 pub trait AsyncWrite: tokio::io::AsyncWrite + Unpin + Send {}
 impl AsyncWrite for webtransport_quinn::SendStream {}
+impl AsyncWrite for Vec<u8> {}
+
+#[async_trait::async_trait]
+pub trait Encode: Sized {
+	async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError>;
+}
 
 /// An encode error.
 #[derive(Error, Debug)]

moq-transport/src/coding/mod.rs

@@ -1,9 +1,11 @@
 mod decode;
 mod encode;
+mod params;
 mod string;
 mod varint;
 
 pub use decode::*;
 pub use encode::*;
+pub use params::*;
 pub use string::*;
 pub use varint::*;

moq-transport/src/coding/params.rs

@@ -1,69 +1,85 @@
-use std::cmp::min;
+use std::io::Cursor;
+use std::{cmp::max, collections::HashMap};
 
-use crate::VarInt;
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
 
-use super::{AsyncRead, AsyncWrite, DecodeError, EncodeError};
+use crate::coding::{AsyncRead, AsyncWrite, Decode, Encode};
-use tokio::io::AsyncReadExt;
 
-// I hate this parameter encoding so much.
+use crate::{
-// i hate it i hate it i hate it
+	coding::{DecodeError, EncodeError},
+	VarInt,
+};
 
-// TODO Use #[async_trait] so we can do Param<VarInt> instead.
+#[derive(Default, Debug, Clone)]
-pub struct ParamInt(pub VarInt);
+pub struct Params(pub HashMap<VarInt, Vec<u8>>);
+
+#[async_trait::async_trait]
+impl Decode for Params {
+	async fn decode<R: AsyncRead>(mut r: &mut R) -> Result<Self, DecodeError> {
+		let mut params = HashMap::new();
+
+		// I hate this shit so much; let me encode my role and get on with my life.
+		let count = VarInt::decode(r).await?;
+		for _ in 0..count.into_inner() {
+			let kind = VarInt::decode(r).await?;
+			if params.contains_key(&kind) {
+				return Err(DecodeError::DupliateParameter);
+			}
 
-impl ParamInt {
-	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
-		// Why do we have a redundant size in front of each VarInt?
 			let size = VarInt::decode(r).await?;
-		let mut take = r.take(size.into_inner());
-		let value = VarInt::decode(&mut take).await?;
 
-		// Like seriously why do I have to check if the VarInt length mismatches.
+			// Don't allocate the entire requested size to avoid a possible attack
-		if take.limit() != 0 {
+			// Instead, we allocate up to 1024 and keep appending as we read further.
-			return Err(DecodeError::InvalidSize);
+			let mut pr = r.take(size.into_inner());
+			let mut buf = Vec::with_capacity(max(1024, pr.limit() as usize));
+			pr.read_to_end(&mut buf).await?;
+			params.insert(kind, buf);
+
+			r = pr.into_inner();
 		}
 
-		Ok(Self(value))
+		Ok(Params(params))
 	}
+}
 
-	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
+#[async_trait::async_trait]
-		// Seriously why do I have to compute the size.
+impl Encode for Params {
-		let size = self.0.size();
+	async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
-		VarInt::try_from(size)?.encode(w).await?;
+		VarInt::try_from(self.0.len())?.encode(w).await?;
 
-		self.0.encode(w).await?;
+		for (kind, value) in self.0.iter() {
+			kind.encode(w).await?;
+			VarInt::try_from(value.len())?.encode(w).await?;
+			w.write_all(value).await?;
+		}
 
 		Ok(())
 	}
 }
 
-pub struct ParamBytes(pub Vec<u8>);
+impl Params {
-
+	pub fn new() -> Self {
-impl ParamBytes {
+		Self::default()
-	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
-		let size = VarInt::decode(r).await?;
-		let mut take = r.take(size.into_inner());
-		let mut buf = Vec::with_capacity(min(take.limit() as usize, 1024));
-		take.read_to_end(&mut buf).await?;
-
-		Ok(Self(buf))
 	}
 
-	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
+	pub async fn set<P: Encode>(&mut self, kind: VarInt, p: P) -> Result<(), EncodeError> {
-		let size = VarInt::try_from(self.0.len())?;
+		let mut value = Vec::new();
-		size.encode(w).await?;
+		p.encode(&mut value).await?;
-		w.write_all(&self.0).await?;
+		self.0.insert(kind, value);
 
 		Ok(())
 	}
-}
 
-pub struct ParamUnknown {}
+	pub fn has(&self, kind: VarInt) -> bool {
+		self.0.contains_key(&kind)
+	}
 
-impl ParamUnknown {
+	pub async fn get<P: Decode>(&mut self, kind: VarInt) -> Result<Option<P>, DecodeError> {
-	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<(), DecodeError> {
+		if let Some(value) = self.0.remove(&kind) {
-		// Really? Is there no way to advance without reading?
+			let mut cursor = Cursor::new(value);
-		ParamBytes::decode(r).await?;
+			Ok(Some(P::decode(&mut cursor).await?))
-		Ok(())
+		} else {
+			Ok(None)
+		}
 	}
 }

moq-transport/src/coding/string.rs

@@ -5,20 +5,25 @@ use tokio::io::{AsyncReadExt, AsyncWriteExt};
 
 use crate::VarInt;
 
-use super::{DecodeError, EncodeError};
+use super::{Decode, DecodeError, Encode, EncodeError};
 
-/// Encode a string with a varint length prefix.
+#[async_trait::async_trait]
-pub async fn encode_string<W: AsyncWrite>(s: &str, w: &mut W) -> Result<(), EncodeError> {
+impl Encode for String {
-	let size = VarInt::try_from(s.len())?;
+	async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
+		let size = VarInt::try_from(self.len())?;
 		size.encode(w).await?;
-	w.write_all(s.as_ref()).await?;
+		w.write_all(self.as_ref()).await?;
 		Ok(())
+	}
 }
 
-/// Decode a string with a varint length prefix.
+#[async_trait::async_trait]
-pub async fn decode_string<R: AsyncRead>(r: &mut R) -> Result<String, DecodeError> {
+impl Decode for String {
+	/// Decode a string with a varint length prefix.
+	async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
 		let size = VarInt::decode(r).await?.into_inner();
 		let mut str = String::with_capacity(min(1024, size) as usize);
 		r.take(size).read_to_string(&mut str).await?;
 		Ok(str)
+	}
 }

moq-transport/src/coding/varint.rs

@@ -9,7 +9,7 @@ use crate::coding::{AsyncRead, AsyncWrite};
 use thiserror::Error;
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
 
-use super::{DecodeError, EncodeError};
+use super::{Decode, DecodeError, Encode, EncodeError};
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Error)]
 #[error("value out of range")]
@@ -164,14 +164,23 @@ impl fmt::Display for VarInt {
 	}
 }
 
-impl VarInt {
+#[async_trait::async_trait]
+impl Decode for VarInt {
 	/// Decode a varint from the given reader.
-	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
+	async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
-		let mut buf = [0u8; 8];
+		let b = r.read_u8().await?;
-		r.read_exact(buf[0..1].as_mut()).await?;
+		Self::decode_byte(b, r).await
+	}
+}
 
-		let tag = buf[0] >> 6;
+impl VarInt {
-		buf[0] &= 0b0011_1111;
+	/// Decode a varint given the first byte, reading the rest as needed.
+	/// This is silly but useful for determining if the stream has ended.
+	pub async fn decode_byte<R: AsyncRead>(b: u8, r: &mut R) -> Result<Self, DecodeError> {
+		let tag = b >> 6;
+
+		let mut buf = [0u8; 8];
+		buf[0] = b & 0b0011_1111;
 
 		let x = match tag {
 			0b00 => u64::from(buf[0]),
@@ -192,9 +201,12 @@ impl VarInt {
 
 		Ok(Self(x))
 	}
+}
 
+#[async_trait::async_trait]
+impl Encode for VarInt {
 	/// Encode a varint to the given writer.
-	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
+	async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
 		let x = self.0;
 		if x < 2u64.pow(6) {
 			w.write_u8(x as u8).await?;

moq-transport/src/error.rs

@@ -1,5 +1,7 @@
 pub trait MoqError {
 	/// An integer code that is sent over the wire.
 	fn code(&self) -> u32;
-	fn reason(&self) -> &str;
+
+	/// An optional reason sometimes sent over the wire.
+	fn reason(&self) -> String;
 }

moq-transport/src/lib.rs

@@ -5,8 +5,8 @@
 //! The specification is a work in progress and will change.
 //! See the [specification](https://datatracker.ietf.org/doc/draft-ietf-moq-transport/) and [github](https://github.com/moq-wg/moq-transport) for any updates.
 //!
-//! **FORKED**: This is implementation makes extensive changes to the protocol.
+//! **FORKED**: This implementation makes some changes to the protocol.
-//! See [KIXEL_00](crate::setup::Version::KIXEL_00) for a list of differences.
+//! See [KIXEL_01](crate::setup::Version::KIXEL_01) for a list of differences.
 //! Many of these will get merged into the specification, so don't panic.
 mod coding;
 mod error;

moq-transport/src/message/announce.rs

@@ -1,22 +1,29 @@
-use crate::coding::{decode_string, encode_string, DecodeError, EncodeError};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, Params};
 
 use crate::coding::{AsyncRead, AsyncWrite};
 
 /// Sent by the publisher to announce the availability of a group of tracks.
 #[derive(Clone, Debug)]
 pub struct Announce {
-	// The track namespace
+	/// The track namespace
 	pub namespace: String,
+
+	/// Optional parameters
+	pub params: Params,
 }
 
 impl Announce {
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
-		let namespace = decode_string(r).await?;
+		let namespace = String::decode(r).await?;
-		Ok(Self { namespace })
+		let params = Params::decode(r).await?;
+
+		Ok(Self { namespace, params })
 	}
 
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
-		encode_string(&self.namespace, w).await?;
+		self.namespace.encode(w).await?;
+		self.params.encode(w).await?;
+
 		Ok(())
 	}
 }

moq-transport/src/message/announce_ok.rs

@@ -1,4 +1,4 @@
-use crate::coding::{decode_string, encode_string, AsyncRead, AsyncWrite, DecodeError, EncodeError};
+use crate::coding::{AsyncRead, AsyncWrite, Decode, DecodeError, Encode, EncodeError};
 
 /// Sent by the subscriber to accept an Announce.
 #[derive(Clone, Debug)]
@@ -10,11 +10,11 @@ pub struct AnnounceOk {
 
 impl AnnounceOk {
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
-		let namespace = decode_string(r).await?;
+		let namespace = String::decode(r).await?;
 		Ok(Self { namespace })
 	}
 
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
-		encode_string(&self.namespace, w).await
+		self.namespace.encode(w).await
 	}
 }

moq-transport/src/message/announce_reset.rs

@@ -1,10 +1,10 @@
-use crate::coding::{decode_string, encode_string, DecodeError, EncodeError, VarInt};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
 
 use crate::coding::{AsyncRead, AsyncWrite};
 
 /// Sent by the subscriber to reject an Announce.
 #[derive(Clone, Debug)]
-pub struct AnnounceReset {
+pub struct AnnounceError {
 	// Echo back the namespace that was reset
 	pub namespace: String,
 
@@ -15,11 +15,11 @@ pub struct AnnounceReset {
 	pub reason: String,
 }
 
-impl AnnounceReset {
+impl AnnounceError {
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
-		let namespace = decode_string(r).await?;
+		let namespace = String::decode(r).await?;
 		let code = VarInt::decode(r).await?.try_into()?;
-		let reason = decode_string(r).await?;
+		let reason = String::decode(r).await?;
 
 		Ok(Self {
 			namespace,
@@ -29,9 +29,9 @@ impl AnnounceReset {
 	}
 
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
-		encode_string(&self.namespace, w).await?;
+		self.namespace.encode(w).await?;
 		VarInt::from_u32(self.code).encode(w).await?;
-		encode_string(&self.reason, w).await?;
+		self.reason.encode(w).await?;
 
 		Ok(())
 	}

moq-transport/src/message/go_away.rs

@@ -1,4 +1,4 @@
-use crate::coding::{decode_string, encode_string, DecodeError, EncodeError};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError};
 
 use crate::coding::{AsyncRead, AsyncWrite};
 
@@ -10,11 +10,11 @@ pub struct GoAway {
 
 impl GoAway {
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
-		let url = decode_string(r).await?;
+		let url = String::decode(r).await?;
 		Ok(Self { url })
 	}
 
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
-		encode_string(&self.url, w).await
+		self.url.encode(w).await
 	}
 }

moq-transport/src/message/mod.rs

@@ -6,16 +6,17 @@
 //!
 //! Messages sent by the publisher:
 //! - [Announce]
-//! - [AnnounceReset]
+//! - [Unannounce]
 //! - [SubscribeOk]
+//! - [SubscribeError]
 //! - [SubscribeReset]
 //! - [Object]
 //!
 //! Messages sent by the subscriber:
 //! - [Subscribe]
-//! - [SubscribeStop]
+//! - [Unsubscribe]
 //! - [AnnounceOk]
-//! - [AnnounceStop]
+//! - [AnnounceError]
 //!
 //! Example flow:
 //! ```test
@@ -32,26 +33,30 @@
 mod announce;
 mod announce_ok;
 mod announce_reset;
-mod announce_stop;
 mod go_away;
 mod object;
 mod subscribe;
+mod subscribe_error;
+mod subscribe_fin;
 mod subscribe_ok;
 mod subscribe_reset;
-mod subscribe_stop;
+mod unannounce;
+mod unsubscribe;
 
 pub use announce::*;
 pub use announce_ok::*;
 pub use announce_reset::*;
-pub use announce_stop::*;
 pub use go_away::*;
 pub use object::*;
 pub use subscribe::*;
+pub use subscribe_error::*;
+pub use subscribe_fin::*;
 pub use subscribe_ok::*;
 pub use subscribe_reset::*;
-pub use subscribe_stop::*;
+pub use unannounce::*;
+pub use unsubscribe::*;
 
-use crate::coding::{DecodeError, EncodeError, VarInt};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
 
 use std::fmt;
 
@@ -76,7 +81,7 @@ macro_rules! message_types {
 						let msg = $name::decode(r).await?;
 						Ok(Self::$name(msg))
 					})*
-					_ => Err(DecodeError::InvalidType(t)),
+					_ => Err(DecodeError::InvalidMessage(t)),
 				}
 			}
 
@@ -127,15 +132,28 @@ macro_rules! message_types {
 message_types! {
 	// NOTE: Object and Setup are in other modules.
 	// Object = 0x0
-	// SetupClient = 0x1
+	// ObjectUnbounded = 0x2
-	// SetupServer = 0x2
+	// SetupClient = 0x40
+	// SetupServer = 0x41
+
+	// SUBSCRIBE family, sent by subscriber
 	Subscribe = 0x3,
+	Unsubscribe = 0xa,
+
+	// SUBSCRIBE family, sent by publisher
 	SubscribeOk = 0x4,
-	SubscribeReset = 0x5,
+	SubscribeError = 0x5,
-	SubscribeStop = 0x15,
+	SubscribeFin = 0xb,
+	SubscribeReset = 0xc,
+
+	// ANNOUNCE family, sent by publisher
 	Announce = 0x6,
+	Unannounce = 0x9,
+
+	// ANNOUNCE family, sent by subscriber
 	AnnounceOk = 0x7,
-	AnnounceReset = 0x8,
+	AnnounceError = 0x8,
-	AnnounceStop = 0x18,
+
+	// Misc
 	GoAway = 0x10,
 }

moq-transport/src/message/object.rs

@@ -1,9 +1,9 @@
-use std::time;
+use std::{io, time};
 
-use crate::coding::{DecodeError, EncodeError, VarInt};
+use tokio::io::AsyncReadExt;
 
 use crate::coding::{AsyncRead, AsyncWrite};
-use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
 
 /// Sent by the publisher as the header of each data stream.
 #[derive(Clone, Debug)]
@@ -13,47 +13,75 @@ pub struct Object {
 	pub track: VarInt,
 
 	// The sequence number within the track.
+	pub group: VarInt,
+
+	// The sequence number within the group.
 	pub sequence: VarInt,
 
-	// The priority, where **larger** values are sent first.
+	// The priority, where **smaller** values are sent first.
-	// Proposal: int32 instead of a varint.
+	pub priority: u32,
-	pub priority: i32,
 
 	// Cache the object for at most this many seconds.
 	// Zero means never expire.
 	pub expires: Option<time::Duration>,
+
+	/// An optional size, allowing multiple OBJECTs on the same stream.
+	pub size: Option<VarInt>,
 }
 
 impl Object {
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
-		let typ = VarInt::decode(r).await?;
+		// Try reading the first byte, returning a special error if the stream naturally ended.
-		if typ.into_inner() != 0 {
+		let typ = match r.read_u8().await {
-			return Err(DecodeError::InvalidType(typ));
+			Ok(b) => VarInt::decode_byte(b, r).await?,
-		}
+			Err(e) if e.kind() == io::ErrorKind::UnexpectedEof => return Err(DecodeError::Final),
+			Err(e) => return Err(e.into()),
+		};
 
-		// NOTE: size has been omitted
+		let size_present = match typ.into_inner() {
+			0 => false,
+			2 => true,
+			_ => return Err(DecodeError::InvalidMessage(typ)),
+		};
 
 		let track = VarInt::decode(r).await?;
+		let group = VarInt::decode(r).await?;
 		let sequence = VarInt::decode(r).await?;
-		let priority = r.read_i32().await?; // big-endian
+		let priority = VarInt::decode(r).await?.try_into()?;
+
 		let expires = match VarInt::decode(r).await?.into_inner() {
 			0 => None,
 			secs => Some(time::Duration::from_secs(secs)),
 		};
 
+		// The presence of the size field depends on the type.
+		let size = match size_present {
+			true => Some(VarInt::decode(r).await?),
+			false => None,
+		};
+
 		Ok(Self {
 			track,
+			group,
 			sequence,
 			priority,
 			expires,
+			size,
 		})
 	}
 
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
-		VarInt::ZERO.encode(w).await?;
+		// The kind changes based on the presence of the size.
+		let kind = match self.size {
+			Some(_) => VarInt::from_u32(2),
+			None => VarInt::ZERO,
+		};
+
+		kind.encode(w).await?;
 		self.track.encode(w).await?;
+		self.group.encode(w).await?;
 		self.sequence.encode(w).await?;
-		w.write_i32(self.priority).await?;
+		VarInt::from_u32(self.priority).encode(w).await?;
 
 		// Round up if there's any decimal points.
 		let expires = match self.expires {
@@ -65,6 +93,10 @@ impl Object {
 
 		VarInt::try_from(expires)?.encode(w).await?;
 
+		if let Some(size) = self.size {
+			size.encode(w).await?;
+		}
+
 		Ok(())
 	}
 }

moq-transport/src/message/subscribe.rs

@@ -1,4 +1,4 @@
-use crate::coding::{decode_string, encode_string, DecodeError, EncodeError, VarInt};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, Params, VarInt};
 
 use crate::coding::{AsyncRead, AsyncWrite};
 
@@ -7,32 +7,119 @@ use crate::coding::{AsyncRead, AsyncWrite};
 /// Objects will use the provided ID instead of the full track name, to save bytes.
 #[derive(Clone, Debug)]
 pub struct Subscribe {
-	// An ID we choose so we can map to the track_name.
+	/// An ID we choose so we can map to the track_name.
 	// Proposal: https://github.com/moq-wg/moq-transport/issues/209
 	pub id: VarInt,
 
-	// The track namespace.
+	/// The track namespace.
 	pub namespace: String,
 
-	// The track name.
+	/// The track name.
 	pub name: String,
+
+	/// The start/end group/object.
+	pub start_group: SubscribeLocation,
+	pub start_object: SubscribeLocation,
+	pub end_group: SubscribeLocation,
+	pub end_object: SubscribeLocation,
+
+	/// Optional parameters
+	pub params: Params,
 }
 
 impl Subscribe {
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
 		let id = VarInt::decode(r).await?;
-		let namespace = decode_string(r).await?;
+		let namespace = String::decode(r).await?;
-		let name = decode_string(r).await?;
+		let name = String::decode(r).await?;
 
-		Ok(Self { id, namespace, name })
+		let start_group = SubscribeLocation::decode(r).await?;
+		let start_object = SubscribeLocation::decode(r).await?;
+		let end_group = SubscribeLocation::decode(r).await?;
+		let end_object = SubscribeLocation::decode(r).await?;
+
+		// You can't have a start object without a start group.
+		if start_group == SubscribeLocation::None && start_object != SubscribeLocation::None {
+			return Err(DecodeError::InvalidSubscribeLocation);
+		}
+
+		// You can't have an end object without an end group.
+		if end_group == SubscribeLocation::None && end_object != SubscribeLocation::None {
+			return Err(DecodeError::InvalidSubscribeLocation);
+		}
+
+		// NOTE: There's some more location restrictions in the draft, but they're enforced at a higher level.
+
+		let params = Params::decode(r).await?;
+
+		Ok(Self {
+			id,
+			namespace,
+			name,
+			start_group,
+			start_object,
+			end_group,
+			end_object,
+			params,
+		})
 	}
-}
 
-impl Subscribe {
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
 		self.id.encode(w).await?;
-		encode_string(&self.namespace, w).await?;
+		self.namespace.encode(w).await?;
-		encode_string(&self.name, w).await?;
+		self.name.encode(w).await?;
+
+		self.start_group.encode(w).await?;
+		self.start_object.encode(w).await?;
+		self.end_group.encode(w).await?;
+		self.end_object.encode(w).await?;
+
+		self.params.encode(w).await?;
+
+		Ok(())
+	}
+}
+
+/// Signal where the subscription should begin, relative to the current cache.
+#[derive(Clone, Debug, PartialEq)]
+pub enum SubscribeLocation {
+	None,
+	Absolute(VarInt),
+	Latest(VarInt),
+	Future(VarInt),
+}
+
+impl SubscribeLocation {
+	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
+		let kind = VarInt::decode(r).await?;
+
+		match kind.into_inner() {
+			0 => Ok(Self::None),
+			1 => Ok(Self::Absolute(VarInt::decode(r).await?)),
+			2 => Ok(Self::Latest(VarInt::decode(r).await?)),
+			3 => Ok(Self::Future(VarInt::decode(r).await?)),
+			_ => Err(DecodeError::InvalidSubscribeLocation),
+		}
+	}
+
+	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
+		match self {
+			Self::None => {
+				VarInt::from_u32(0).encode(w).await?;
+			}
+			Self::Absolute(val) => {
+				VarInt::from_u32(1).encode(w).await?;
+				val.encode(w).await?;
+			}
+			Self::Latest(val) => {
+				VarInt::from_u32(2).encode(w).await?;
+				val.encode(w).await?;
+			}
+			Self::Future(val) => {
+				VarInt::from_u32(3).encode(w).await?;
+				val.encode(w).await?;
+			}
+		}
 
 		Ok(())
 	}

moq-transport/src/message/subscribe_error.rs

@@ -0,0 +1,35 @@
+use crate::coding::{AsyncRead, AsyncWrite};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
+
+/// Sent by the publisher to reject a Subscribe.
+#[derive(Clone, Debug)]
+pub struct SubscribeError {
+	// NOTE: No full track name because of this proposal: https://github.com/moq-wg/moq-transport/issues/209
+
+	// The ID for this subscription.
+	pub id: VarInt,
+
+	// An error code.
+	pub code: u32,
+
+	// An optional, human-readable reason.
+	pub reason: String,
+}
+
+impl SubscribeError {
+	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
+		let id = VarInt::decode(r).await?;
+		let code = VarInt::decode(r).await?.try_into()?;
+		let reason = String::decode(r).await?;
+
+		Ok(Self { id, code, reason })
+	}
+
+	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
+		self.id.encode(w).await?;
+		VarInt::from_u32(self.code).encode(w).await?;
+		self.reason.encode(w).await?;
+
+		Ok(())
+	}
+}

moq-transport/src/message/subscribe_fin.rs

@@ -0,0 +1,36 @@
+use crate::coding::{AsyncRead, AsyncWrite};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
+
+/// Sent by the publisher to cleanly terminate a Subscribe.
+#[derive(Clone, Debug)]
+pub struct SubscribeFin {
+	// NOTE: No full track name because of this proposal: https://github.com/moq-wg/moq-transport/issues/209
+	/// The ID for this subscription.
+	pub id: VarInt,
+
+	/// The final group/object sent on this subscription.
+	pub final_group: VarInt,
+	pub final_object: VarInt,
+}
+
+impl SubscribeFin {
+	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
+		let id = VarInt::decode(r).await?;
+		let final_group = VarInt::decode(r).await?;
+		let final_object = VarInt::decode(r).await?;
+
+		Ok(Self {
+			id,
+			final_group,
+			final_object,
+		})
+	}
+
+	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
+		self.id.encode(w).await?;
+		self.final_group.encode(w).await?;
+		self.final_object.encode(w).await?;
+
+		Ok(())
+	}
+}

moq-transport/src/message/subscribe_ok.rs

@@ -1,4 +1,4 @@
-use crate::coding::{DecodeError, EncodeError, VarInt};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
 
 use crate::coding::{AsyncRead, AsyncWrite};
 
@@ -6,21 +6,25 @@ use crate::coding::{AsyncRead, AsyncWrite};
 #[derive(Clone, Debug)]
 pub struct SubscribeOk {
 	// NOTE: No full track name because of this proposal: https://github.com/moq-wg/moq-transport/issues/209
-
+	/// The ID for this track.
-	// The ID for this track.
 	pub id: VarInt,
+
+	/// The subscription will expire in this many milliseconds.
+	pub expires: VarInt,
 }
 
 impl SubscribeOk {
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
 		let id = VarInt::decode(r).await?;
-		Ok(Self { id })
+		let expires = VarInt::decode(r).await?;
+		Ok(Self { id, expires })
 	}
 }
 
 impl SubscribeOk {
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
 		self.id.encode(w).await?;
+		self.expires.encode(w).await?;
 		Ok(())
 	}
 }

moq-transport/src/message/subscribe_reset.rs

@@ -1,35 +1,48 @@
-use crate::coding::{decode_string, encode_string, DecodeError, EncodeError, VarInt};
-
 use crate::coding::{AsyncRead, AsyncWrite};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
 
-/// Sent by the publisher to reject a Subscribe.
+/// Sent by the publisher to terminate a Subscribe.
 #[derive(Clone, Debug)]
 pub struct SubscribeReset {
 	// NOTE: No full track name because of this proposal: https://github.com/moq-wg/moq-transport/issues/209
-
+	/// The ID for this subscription.
-	// The ID for this subscription.
 	pub id: VarInt,
 
-	// An error code.
+	/// An error code.
 	pub code: u32,
 
-	// An optional, human-readable reason.
+	/// An optional, human-readable reason.
 	pub reason: String,
+
+	/// The final group/object sent on this subscription.
+	pub final_group: VarInt,
+	pub final_object: VarInt,
 }
 
 impl SubscribeReset {
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
 		let id = VarInt::decode(r).await?;
 		let code = VarInt::decode(r).await?.try_into()?;
-		let reason = decode_string(r).await?;
+		let reason = String::decode(r).await?;
+		let final_group = VarInt::decode(r).await?;
+		let final_object = VarInt::decode(r).await?;
 
-		Ok(Self { id, code, reason })
+		Ok(Self {
+			id,
+			code,
+			reason,
+			final_group,
+			final_object,
+		})
 	}
 
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
 		self.id.encode(w).await?;
 		VarInt::from_u32(self.code).encode(w).await?;
-		encode_string(&self.reason, w).await?;
+		self.reason.encode(w).await?;
+
+		self.final_group.encode(w).await?;
+		self.final_object.encode(w).await?;
 
 		Ok(())
 	}

moq-transport/src/message/unannounce.rs

@@ -1,23 +1,23 @@
-use crate::coding::{decode_string, encode_string, DecodeError, EncodeError};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError};
 
 use crate::coding::{AsyncRead, AsyncWrite};
 
 /// Sent by the publisher to terminate an Announce.
 #[derive(Clone, Debug)]
-pub struct AnnounceStop {
+pub struct Unannounce {
 	// Echo back the namespace that was reset
 	pub namespace: String,
 }
 
-impl AnnounceStop {
+impl Unannounce {
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
-		let namespace = decode_string(r).await?;
+		let namespace = String::decode(r).await?;
 
 		Ok(Self { namespace })
 	}
 
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
-		encode_string(&self.namespace, w).await?;
+		self.namespace.encode(w).await?;
 
 		Ok(())
 	}

moq-transport/src/message/unsubscribe.rs

@@ -1,24 +1,24 @@
-use crate::coding::{DecodeError, EncodeError, VarInt};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
 
 use crate::coding::{AsyncRead, AsyncWrite};
 
 /// Sent by the subscriber to terminate a Subscribe.
 #[derive(Clone, Debug)]
-pub struct SubscribeStop {
+pub struct Unsubscribe {
 	// NOTE: No full track name because of this proposal: https://github.com/moq-wg/moq-transport/issues/209
 
 	// The ID for this subscription.
 	pub id: VarInt,
 }
 
-impl SubscribeStop {
+impl Unsubscribe {
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
 		let id = VarInt::decode(r).await?;
 		Ok(Self { id })
 	}
 }
 
-impl SubscribeStop {
+impl Unsubscribe {
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
 		self.id.encode(w).await?;
 		Ok(())

moq-transport/src/session/client.rs

@@ -34,20 +34,19 @@ impl Client {
 
 		let client = setup::Client {
 			role,
-			versions: vec![setup::Version::KIXEL_00].into(),
+			versions: vec![setup::Version::KIXEL_01].into(),
+			params: Default::default(),
 		};
 
 		client.encode(&mut control.0).await?;
 
 		let server = setup::Server::decode(&mut control.1).await?;
 
-		if server.version != setup::Version::KIXEL_00 {
+		if server.version != setup::Version::KIXEL_01 {
-			return Err(SessionError::Version(Some(server.version)));
+			return Err(SessionError::Version(
-		}
+				vec![setup::Version::KIXEL_01].into(),
-
+				vec![server.version].into(),
-		// Make sure the server replied with the
+			));
-		if !client.role.is_compatible(server.role) {
-			return Err(SessionError::RoleIncompatible(client.role, server.role));
 		}
 
 		Ok(control)

moq-transport/src/session/error.rs

@@ -14,8 +14,8 @@ pub enum SessionError {
 	#[error("decode error: {0}")]
 	Decode(#[from] coding::DecodeError),
 
-	#[error("unsupported version: {0:?}")]
+	#[error("unsupported versions: client={0:?} server={1:?}")]
-	Version(Option<setup::Version>),
+	Version(setup::Versions, setup::Versions),
 
 	#[error("incompatible roles: client={0:?} server={1:?}")]
 	RoleIncompatible(setup::Role, setup::Role),
@@ -32,6 +32,18 @@ pub enum SessionError {
 	#[error("role violation: msg={0}")]
 	RoleViolation(VarInt),
 
+	/// Our enforced stream mapping was disrespected.
+	#[error("stream mapping conflict")]
+	StreamMapping,
+
+	/// The priority was invalid.
+	#[error("invalid priority: {0}")]
+	InvalidPriority(VarInt),
+
+	/// The size was invalid.
+	#[error("invalid size: {0}")]
+	InvalidSize(VarInt),
+
 	/// An unclassified error because I'm lazy. TODO classify these errors
 	#[error("unknown error: {0}")]
 	Unknown(String),
@@ -44,29 +56,40 @@ impl MoqError for SessionError {
 			Self::Cache(err) => err.code(),
 			Self::RoleIncompatible(..) => 406,
 			Self::RoleViolation(..) => 405,
+			Self::StreamMapping => 409,
 			Self::Unknown(_) => 500,
 			Self::Write(_) => 501,
 			Self::Read(_) => 502,
 			Self::Session(_) => 503,
-			Self::Version(_) => 406,
+			Self::Version(..) => 406,
 			Self::Encode(_) => 500,
 			Self::Decode(_) => 500,
+			Self::InvalidPriority(_) => 400,
+			Self::InvalidSize(_) => 400,
 		}
 	}
 
 	/// A reason that is sent over the wire.
-	fn reason(&self) -> &str {
+	fn reason(&self) -> String {
 		match self {
 			Self::Cache(err) => err.reason(),
-			Self::RoleViolation(_) => "role violation",
+			Self::RoleViolation(kind) => format!("role violation for message type {:?}", kind),
-			Self::RoleIncompatible(..) => "role incompatible",
+			Self::RoleIncompatible(client, server) => {
-			Self::Read(_) => "read error",
+				format!(
-			Self::Write(_) => "write error",
+					"role incompatible: client wanted {:?} but server wanted {:?}",
-			Self::Session(_) => "session error",
+					client, server
-			Self::Unknown(_) => "unknown",
+				)
-			Self::Version(_) => "unsupported version",
+			}
-			Self::Encode(_) => "encode error",
+			Self::Read(err) => format!("read error: {}", err),
-			Self::Decode(_) => "decode error",
+			Self::Write(err) => format!("write error: {}", err),
+			Self::Session(err) => format!("session error: {}", err),
+			Self::Unknown(err) => format!("unknown error: {}", err),
+			Self::Version(client, server) => format!("unsupported versions: client={:?} server={:?}", client, server),
+			Self::Encode(err) => format!("encode error: {}", err),
+			Self::Decode(err) => format!("decode error: {}", err),
+			Self::StreamMapping => "streaming mapping conflict".to_owned(),
+			Self::InvalidPriority(priority) => format!("invalid priority: {}", priority),
+			Self::InvalidSize(size) => format!("invalid size: {}", size),
 		}
 	}
 }

moq-transport/src/session/publisher.rs

@@ -85,9 +85,9 @@ impl Publisher {
 	async fn recv_message(&mut self, msg: &Message) -> Result<(), SessionError> {
 		match msg {
 			Message::AnnounceOk(msg) => self.recv_announce_ok(msg).await,
-			Message::AnnounceStop(msg) => self.recv_announce_stop(msg).await,
+			Message::AnnounceError(msg) => self.recv_announce_error(msg).await,
 			Message::Subscribe(msg) => self.recv_subscribe(msg).await,
-			Message::SubscribeStop(msg) => self.recv_subscribe_stop(msg).await,
+			Message::Unsubscribe(msg) => self.recv_unsubscribe(msg).await,
 			_ => Err(SessionError::RoleViolation(msg.id())),
 		}
 	}
@@ -97,7 +97,7 @@ impl Publisher {
 		Err(CacheError::NotFound.into())
 	}
 
-	async fn recv_announce_stop(&mut self, _msg: &message::AnnounceStop) -> Result<(), SessionError> {
+	async fn recv_announce_error(&mut self, _msg: &message::AnnounceError) -> Result<(), SessionError> {
 		// We didn't send an announce.
 		Err(CacheError::NotFound.into())
 	}
@@ -115,14 +115,24 @@ impl Publisher {
 			hash_map::Entry::Vacant(entry) => entry.insert(abort),
 		};
 
-		self.control.send(message::SubscribeOk { id: msg.id }).await
+		self.control
+			.send(message::SubscribeOk {
+				id: msg.id,
+				expires: VarInt::ZERO,
+			})
+			.await
 	}
 
 	async fn reset_subscribe<E: MoqError>(&mut self, id: VarInt, err: E) -> Result<(), SessionError> {
 		let msg = message::SubscribeReset {
 			id,
 			code: err.code(),
-			reason: err.reason().to_string(),
+			reason: err.reason(),
+
+			// TODO properly populate these
+			// But first: https://github.com/moq-wg/moq-transport/issues/313
+			final_group: VarInt::ZERO,
+			final_object: VarInt::ZERO,
 		};
 
 		self.control.send(msg).await
@@ -176,31 +186,42 @@ impl Publisher {
 	}
 
 	async fn run_segment(&self, id: VarInt, segment: &mut segment::Subscriber) -> Result<(), SessionError> {
-		let object = message::Object {
+		log::trace!("serving group: {:?}", segment);
-			track: id,
-			sequence: segment.sequence,
-			priority: segment.priority,
-			expires: segment.expires,
-		};
-
-		log::trace!("serving object: {:?}", object);
 
 		let mut stream = self.webtransport.open_uni().await?;
-		stream.set_priority(object.priority).ok();
+
+		// Convert the u32 to a i32, since the Quinn set_priority is signed.
+		let priority = (segment.priority as i64 - i32::MAX as i64) as i32;
+		stream.set_priority(priority).ok();
+
+		while let Some(mut fragment) = segment.next_fragment().await? {
+			let object = message::Object {
+				track: id,
+
+				// Properties of the segment
+				group: segment.sequence,
+				priority: segment.priority,
+				expires: segment.expires,
+
+				// Properties of the fragment
+				sequence: fragment.sequence,
+				size: fragment.size,
+			};
 
 			object
 				.encode(&mut stream)
 				.await
 				.map_err(|e| SessionError::Unknown(e.to_string()))?;
 
-		while let Some(data) = segment.read_chunk().await? {
+			while let Some(chunk) = fragment.read_chunk().await? {
-			stream.write_chunk(data).await?;
+				stream.write_all(&chunk).await?;
+			}
 		}
 
 		Ok(())
 	}
 
-	async fn recv_subscribe_stop(&mut self, msg: &message::SubscribeStop) -> Result<(), SessionError> {
+	async fn recv_unsubscribe(&mut self, msg: &message::Unsubscribe) -> Result<(), SessionError> {
 		let abort = self
 			.subscribes
 			.lock()

moq-transport/src/session/server.rs

@@ -18,8 +18,8 @@ impl Server {
 		client
 			.versions
 			.iter()
-			.find(|version| **version == setup::Version::KIXEL_00)
+			.find(|version| **version == setup::Version::KIXEL_01)
-			.ok_or_else(|| SessionError::Version(client.versions.last().cloned()))?;
+			.ok_or_else(|| SessionError::Version(client.versions.clone(), vec![setup::Version::KIXEL_01].into()))?;
 
 		Ok(Request {
 			session,
@@ -63,7 +63,8 @@ impl Request {
 	async fn send_setup(&mut self, role: setup::Role) -> Result<(), SessionError> {
 		let server = setup::Server {
 			role,
-			version: setup::Version::KIXEL_00,
+			version: setup::Version::KIXEL_01,
+			params: Default::default(),
 		};
 
 		// We need to sure we support the opposite of the client's role.

moq-transport/src/session/subscriber.rs

@@ -6,7 +6,8 @@ use std::{
 };
 
 use crate::{
-	cache::{broadcast, segment, track, CacheError},
+	cache::{broadcast, fragment, segment, track, CacheError},
+	coding::DecodeError,
 	message,
 	message::Message,
 	session::{Control, SessionError},
@@ -64,28 +65,28 @@ impl Subscriber {
 			let msg = self.control.recv().await?;
 
 			log::info!("message received: {:?}", msg);
-			if let Err(err) = self.recv_message(&msg).await {
+			if let Err(err) = self.recv_message(&msg) {
 				log::warn!("message error: {:?} {:?}", err, msg);
 			}
 		}
 	}
 
-	async fn recv_message(&mut self, msg: &Message) -> Result<(), SessionError> {
+	fn recv_message(&mut self, msg: &Message) -> Result<(), SessionError> {
 		match msg {
 			Message::Announce(_) => Ok(()),       // don't care
-			Message::AnnounceReset(_) => Ok(()), // also don't care
+			Message::Unannounce(_) => Ok(()),     // also don't care
-			Message::SubscribeOk(_) => Ok(()),   // guess what, don't care
+			Message::SubscribeOk(_msg) => Ok(()), // don't care
-			Message::SubscribeReset(msg) => self.recv_subscribe_reset(msg).await,
+			Message::SubscribeReset(msg) => self.recv_subscribe_error(msg.id, CacheError::Reset(msg.code)),
+			Message::SubscribeFin(msg) => self.recv_subscribe_error(msg.id, CacheError::Closed),
+			Message::SubscribeError(msg) => self.recv_subscribe_error(msg.id, CacheError::Reset(msg.code)),
 			Message::GoAway(_msg) => unimplemented!("GOAWAY"),
 			_ => Err(SessionError::RoleViolation(msg.id())),
 		}
 	}
 
-	async fn recv_subscribe_reset(&mut self, msg: &message::SubscribeReset) -> Result<(), SessionError> {
+	fn recv_subscribe_error(&mut self, id: VarInt, err: CacheError) -> Result<(), SessionError> {
-		let err = CacheError::Reset(msg.code);
-
 		let mut subscribes = self.subscribes.lock().unwrap();
-		let subscribe = subscribes.remove(&msg.id).ok_or(CacheError::NotFound)?;
+		let subscribe = subscribes.remove(&id).ok_or(CacheError::NotFound)?;
 		subscribe.close(err)?;
 
 		Ok(())
@@ -107,36 +108,82 @@ impl Subscriber {
 
 	async fn run_stream(self, mut stream: RecvStream) -> Result<(), SessionError> {
 		// Decode the object on the data stream.
-		let object = message::Object::decode(&mut stream)
+		let mut object = message::Object::decode(&mut stream)
 			.await
 			.map_err(|e| SessionError::Unknown(e.to_string()))?;
 
 		log::trace!("received object: {:?}", object);
 
 		// A new scope is needed because the async compiler is dumb
-		let mut publisher = {
+		let mut segment = {
 			let mut subscribes = self.subscribes.lock().unwrap();
 			let track = subscribes.get_mut(&object.track).ok_or(CacheError::NotFound)?;
 
 			track.create_segment(segment::Info {
-				sequence: object.sequence,
+				sequence: object.group,
 				priority: object.priority,
 				expires: object.expires,
 			})?
 		};
 
-		while let Some(data) = stream.read_chunk(usize::MAX, true).await? {
+		// Create the first fragment
+		let mut fragment = segment.create_fragment(fragment::Info {
+			sequence: object.sequence,
+			size: object.size,
+		})?;
+
+		let mut remain = object.size.map(usize::from);
+
+		loop {
+			if let Some(0) = remain {
+				// Decode the next object from the stream.
+				let next = match message::Object::decode(&mut stream).await {
+					Ok(next) => next,
+
+					// No more objects
+					Err(DecodeError::Final) => break,
+
+					// Unknown error
+					Err(err) => return Err(err.into()),
+				};
+
+				// NOTE: This is a custom restriction; not part of the moq-transport draft.
+				// We require every OBJECT to contain the same priority since prioritization is done per-stream.
+				// We also require every OBJECT to contain the same group so we know when the group ends, and can detect gaps.
+				if next.priority != object.priority && next.group != object.group {
+					return Err(SessionError::StreamMapping);
+				}
+
+				// Create a new object.
+				fragment = segment.create_fragment(fragment::Info {
+					sequence: object.sequence,
+					size: object.size,
+				})?;
+
+				object = next;
+				remain = object.size.map(usize::from);
+			}
+
+			match stream.read_chunk(remain.unwrap_or(usize::MAX), true).await? {
+				// Unbounded object has ended
+				None if remain.is_none() => break,
+
+				// Bounded object ended early, oops.
+				None => return Err(DecodeError::UnexpectedEnd.into()),
+
 				// NOTE: This does not make a copy!
 				// Bytes are immutable and ref counted.
-			publisher.write_chunk(data.bytes)?;
+				Some(data) => fragment.write_chunk(data.bytes)?,
+			}
 		}
 
 		Ok(())
 	}
 
 	async fn run_source(mut self) -> Result<(), SessionError> {
+		loop {
 			// NOTE: This returns Closed when the source is closed.
-		while let Some(track) = self.source.next_track().await? {
+			let track = self.source.next_track().await?;
 			let name = track.name.clone();
 
 			let id = VarInt::from_u32(self.next.fetch_add(1, atomic::Ordering::SeqCst));
@@ -146,11 +193,17 @@ impl Subscriber {
 				id,
 				namespace: "".to_string(),
 				name,
+
+				// TODO correctly support these
+				start_group: message::SubscribeLocation::Latest(VarInt::ZERO),
+				start_object: message::SubscribeLocation::Absolute(VarInt::ZERO),
+				end_group: message::SubscribeLocation::None,
+				end_object: message::SubscribeLocation::None,
+
+				params: Default::default(),
 			};
 
 			self.control.send(msg).await?;
 		}
-
-		Ok(())
 	}
 }

moq-transport/src/setup/client.rs

@@ -1,6 +1,6 @@
 use super::{Role, Versions};
 use crate::{
-	coding::{DecodeError, EncodeError},
+	coding::{Decode, DecodeError, Encode, EncodeError, Params},
 	VarInt,
 };
 
@@ -15,29 +15,45 @@ pub struct Client {
 	pub versions: Versions,
 
 	/// Indicate if the client is a publisher, a subscriber, or both.
-	// Proposal: moq-wg/moq-transport#151
 	pub role: Role,
+
+	/// Unknown parameters.
+	pub params: Params,
 }
 
 impl Client {
 	/// Decode a client setup message.
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
 		let typ = VarInt::decode(r).await?;
-		if typ.into_inner() != 1 {
+		if typ.into_inner() != 0x40 {
-			return Err(DecodeError::InvalidType(typ));
+			return Err(DecodeError::InvalidMessage(typ));
 		}
 
 		let versions = Versions::decode(r).await?;
-		let role = Role::decode(r).await?;
+		let mut params = Params::decode(r).await?;
 
-		Ok(Self { versions, role })
+		let role = params
+			.get::<Role>(VarInt::from_u32(0))
+			.await?
+			.ok_or(DecodeError::MissingParameter)?;
+
+		// Make sure the PATH parameter isn't used
+		// TODO: This assumes WebTransport support only
+		if params.has(VarInt::from_u32(1)) {
+			return Err(DecodeError::InvalidParameter);
+		}
+
+		Ok(Self { versions, role, params })
 	}
 
 	/// Encode a server setup message.
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
-		VarInt::from_u32(1).encode(w).await?;
+		VarInt::from_u32(0x40).encode(w).await?;
 		self.versions.encode(w).await?;
-		self.role.encode(w).await?;
+
+		let mut params = self.params.clone();
+		params.set(VarInt::from_u32(0), self.role).await?;
+		params.encode(w).await?;
 
 		Ok(())
 	}

moq-transport/src/setup/role.rs

@@ -1,6 +1,6 @@
 use crate::coding::{AsyncRead, AsyncWrite};
 
-use crate::coding::{DecodeError, EncodeError, VarInt};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
 
 /// Indicates the endpoint is a publisher, subscriber, or both.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -36,9 +36,9 @@ impl Role {
 impl From<Role> for VarInt {
 	fn from(r: Role) -> Self {
 		VarInt::from_u32(match r {
-			Role::Publisher => 0x0,
+			Role::Publisher => 0x1,
-			Role::Subscriber => 0x1,
+			Role::Subscriber => 0x2,
-			Role::Both => 0x2,
+			Role::Both => 0x3,
 		})
 	}
 }
@@ -48,23 +48,27 @@ impl TryFrom<VarInt> for Role {
 
 	fn try_from(v: VarInt) -> Result<Self, Self::Error> {
 		match v.into_inner() {
-			0x0 => Ok(Self::Publisher),
+			0x1 => Ok(Self::Publisher),
-			0x1 => Ok(Self::Subscriber),
+			0x2 => Ok(Self::Subscriber),
-			0x2 => Ok(Self::Both),
+			0x3 => Ok(Self::Both),
-			_ => Err(DecodeError::InvalidType(v)),
+			_ => Err(DecodeError::InvalidRole(v)),
 		}
 	}
 }
 
-impl Role {
+#[async_trait::async_trait]
+impl Decode for Role {
 	/// Decode the role.
-	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
+	async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
 		let v = VarInt::decode(r).await?;
 		v.try_into()
 	}
+}
 
+#[async_trait::async_trait]
+impl Encode for Role {
 	/// Encode the role.
-	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
+	async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
 		VarInt::from(*self).encode(w).await
 	}
 }

moq-transport/src/setup/server.rs

@@ -1,6 +1,6 @@
 use super::{Role, Version};
 use crate::{
-	coding::{DecodeError, EncodeError},
+	coding::{Decode, DecodeError, Encode, EncodeError, Params},
 	VarInt,
 };
 
@@ -17,27 +17,43 @@ pub struct Server {
 	/// Indicate if the server is a publisher, a subscriber, or both.
 	// Proposal: moq-wg/moq-transport#151
 	pub role: Role,
+
+	/// Unknown parameters.
+	pub params: Params,
 }
 
 impl Server {
 	/// Decode the server setup.
 	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
 		let typ = VarInt::decode(r).await?;
-		if typ.into_inner() != 2 {
+		if typ.into_inner() != 0x41 {
-			return Err(DecodeError::InvalidType(typ));
+			return Err(DecodeError::InvalidMessage(typ));
 		}
 
 		let version = Version::decode(r).await?;
-		let role = Role::decode(r).await?;
+		let mut params = Params::decode(r).await?;
 
-		Ok(Self { version, role })
+		let role = params
+			.get::<Role>(VarInt::from_u32(0))
+			.await?
+			.ok_or(DecodeError::MissingParameter)?;
+
+		// Make sure the PATH parameter isn't used
+		if params.has(VarInt::from_u32(1)) {
+			return Err(DecodeError::InvalidParameter);
+		}
+
+		Ok(Self { version, role, params })
 	}
 
 	/// Encode the server setup.
 	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
-		VarInt::from_u32(2).encode(w).await?;
+		VarInt::from_u32(0x41).encode(w).await?;
 		self.version.encode(w).await?;
-		self.role.encode(w).await?;
+
+		let mut params = self.params.clone();
+		params.set(VarInt::from_u32(0), self.role).await?;
+		params.encode(w).await?;
 
 		Ok(())
 	}

moq-transport/src/setup/version.rs

@@ -1,4 +1,4 @@
-use crate::coding::{DecodeError, EncodeError, VarInt};
+use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
 
 use crate::coding::{AsyncRead, AsyncWrite};
 
@@ -56,6 +56,19 @@ impl Version {
 	/// # GROUP
 	/// - GROUP concept was removed, replaced with OBJECT as a QUIC stream.
 	pub const KIXEL_00: Version = Version(VarInt::from_u32(0xbad00));
+
+	/// Fork of draft-ietf-moq-transport-01.
+	///
+	/// Most of the KIXEL_00 changes made it into the draft, or were reverted.
+	/// Check out the referenced issue on: github.com/moq-wg/moq-transport
+	///
+	/// - SUBSCRIBE contains a separate track namespace and track name field (accidental revert). [#277](https://github.com/moq-wg/moq-transport/pull/277)
+	/// - SUBSCRIBE contains the `track_id` instead of SUBSCRIBE_OK. [#145](https://github.com/moq-wg/moq-transport/issues/145)
+	/// - SUBSCRIBE_* reference `track_id` the instead of the `track_full_name`. [#145](https://github.com/moq-wg/moq-transport/issues/145)
+	/// - OBJECT `priority` is still a VarInt, but the max value is a u32 (implementation reasons)
+	/// - OBJECT `expires` was added, a VarInt in seconds. [#249](https://github.com/moq-wg/moq-transport/issues/249)
+	/// - OBJECT messages within the same `group` MUST be on the same QUIC stream.
+	pub const KIXEL_01: Version = Version(VarInt::from_u32(0xbad01));
 }
 
 impl From<VarInt> for Version {
@@ -88,9 +101,10 @@ impl Version {
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Versions(Vec<Version>);
 
-impl Versions {
+#[async_trait::async_trait]
+impl Decode for Versions {
 	/// Decode the version list.
-	pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
+	async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
 		let count = VarInt::decode(r).await?.into_inner();
 		let mut vs = Vec::new();
 
@@ -101,9 +115,12 @@ impl Versions {
 
 		Ok(Self(vs))
 	}
+}
 
+#[async_trait::async_trait]
+impl Encode for Versions {
 	/// Encode the version list.
-	pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
+	async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
 		let size: VarInt = self.0.len().try_into()?;
 		size.encode(w).await?;