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[package]
name = "moq-transport"
description = "Media over QUIC"
authors = ["Luke Curley"]
repository = "https://github.com/kixelated/moq-rs"
license = "MIT OR Apache-2.0"
version = "0.2.0"
edition = "2021"
keywords = ["quic", "http3", "webtransport", "media", "live"]
categories = ["multimedia", "network-programming", "web-programming"]
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
bytes = "1"
thiserror = "1"
tokio = { version = "1", features = ["macros", "io-util", "sync"] }
log = "0.4"
indexmap = "2"
quinn = "0.10"
webtransport-quinn = "0.6.1"
#webtransport-quinn = { path = "../../webtransport-rs/webtransport-quinn" }
async-trait = "0.1"
paste = "1"
[dev-dependencies]
# QUIC
url = "2"
# Crypto
rustls = { version = "0.21", features = ["dangerous_configuration"] }
rustls-native-certs = "0.6"
rustls-pemfile = "1"
# Async stuff
tokio = { version = "1", features = ["full"] }
# CLI, logging, error handling
clap = { version = "4", features = ["derive"] }
log = { version = "0.4", features = ["std"] }
env_logger = "0.9"
mp4 = "0.13"
anyhow = { version = "1", features = ["backtrace"] }
serde_json = "1"
rfc6381-codec = "0.1"
tracing = "0.1"
tracing-subscriber = "0.3"

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MIT License
Copyright (c) 2023 Luke Curley
Permission is hereby granted, free of charge, to any person obtaining a copy
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SOFTWARE.

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[![Documentation](https://docs.rs/moq-transport/badge.svg)](https://docs.rs/moq-transport/)
[![Crates.io](https://img.shields.io/crates/v/moq-transport.svg)](https://crates.io/crates/moq-transport)
[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE-MIT)
# moq-transport
A Rust implementation of the proposed IETF standard.
[Specification](https://datatracker.ietf.org/doc/draft-ietf-moq-transport/)
[Github](https://github.com/moq-wg/moq-transport)

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//! A broadcast is a collection of tracks, split into two handles: [Publisher] and [Subscriber].
//!
//! The [Publisher] can create tracks, either manually or on request.
//! It receives all requests by a [Subscriber] for a tracks that don't exist.
//! The simplest implementation is to close every unknown track with [CacheError::NotFound].
//!
//! A [Subscriber] can request tracks by name.
//! If the track already exists, it will be returned.
//! If the track doesn't exist, it will be sent to [Unknown] to be handled.
//! A [Subscriber] can be cloned to create multiple subscriptions.
//!
//! The broadcast is automatically closed with [CacheError::Closed] when [Publisher] is dropped, or all [Subscriber]s are dropped.
use std::{
collections::{hash_map, HashMap, VecDeque},
fmt,
ops::Deref,
sync::Arc,
};
use super::{track, CacheError, Watch};
/// Create a new broadcast.
pub fn new(id: &str) -> (Publisher, Subscriber) {
let state = Watch::new(State::default());
let info = Arc::new(Info { id: id.to_string() });
let publisher = Publisher::new(state.clone(), info.clone());
let subscriber = Subscriber::new(state, info);
(publisher, subscriber)
}
/// Static information about a broadcast.
#[derive(Debug)]
pub struct Info {
pub id: String,
}
/// Dynamic information about the broadcast.
#[derive(Debug)]
struct State {
tracks: HashMap<String, track::Subscriber>,
requested: VecDeque<track::Publisher>,
closed: Result<(), CacheError>,
}
impl State {
pub fn get(&self, name: &str) -> Result<Option<track::Subscriber>, CacheError> {
// Don't check closed, so we can return from cache.
Ok(self.tracks.get(name).cloned())
}
pub fn insert(&mut self, track: track::Subscriber) -> Result<(), CacheError> {
self.closed.clone()?;
match self.tracks.entry(track.name.clone()) {
hash_map::Entry::Occupied(_) => return Err(CacheError::Duplicate),
hash_map::Entry::Vacant(v) => v.insert(track),
};
Ok(())
}
pub fn request(&mut self, name: &str) -> Result<track::Subscriber, CacheError> {
self.closed.clone()?;
// Create a new track.
let (publisher, subscriber) = track::new(name);
// Insert the track into our Map so we deduplicate future requests.
self.tracks.insert(name.to_string(), subscriber.clone());
// Send the track to the Publisher to handle.
self.requested.push_back(publisher);
Ok(subscriber)
}
pub fn has_next(&self) -> Result<bool, CacheError> {
// Check if there's any elements in the queue before checking closed.
if !self.requested.is_empty() {
return Ok(true);
}
self.closed.clone()?;
Ok(false)
}
pub fn next(&mut self) -> track::Publisher {
// We panic instead of erroring to avoid a nasty wakeup loop if you don't call has_next first.
self.requested.pop_front().expect("no entry in queue")
}
pub fn close(&mut self, err: CacheError) -> Result<(), CacheError> {
self.closed.clone()?;
self.closed = Err(err);
Ok(())
}
}
impl Default for State {
fn default() -> Self {
Self {
tracks: HashMap::new(),
closed: Ok(()),
requested: VecDeque::new(),
}
}
}
/// Publish new tracks for a broadcast by name.
// TODO remove Clone
#[derive(Clone)]
pub struct Publisher {
state: Watch<State>,
info: Arc<Info>,
_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 }
}
/// Create a new track with the given name, inserting it into the broadcast.
pub fn create_track(&mut self, name: &str) -> Result<track::Publisher, CacheError> {
let (publisher, subscriber) = track::new(name);
self.state.lock_mut().insert(subscriber)?;
Ok(publisher)
}
/// Insert a track into the broadcast.
pub fn insert_track(&mut self, track: track::Subscriber) -> Result<(), CacheError> {
self.state.lock_mut().insert(track)
}
/// Block until the next track requested by a subscriber.
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(state.into_mut().next());
}
state.changed()
};
notify.await;
}
}
/// Close the broadcast 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()
}
}
/// Subscribe to a broadcast by requesting tracks.
///
/// This can be cloned to create handles.
#[derive(Clone)]
pub struct Subscriber {
state: Watch<State>,
info: Arc<Info>,
_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, _dropped }
}
/// Get a track from the broadcast by name.
/// If the track does not exist, it will be created and potentially fufilled by the publisher (via Unknown).
/// Otherwise, it will return [CacheError::NotFound].
pub fn get_track(&self, name: &str) -> Result<track::Subscriber, CacheError> {
let state = self.state.lock();
if let Some(track) = state.get(name)? {
return Ok(track);
}
// Request a new track if it does not exist.
state.into_mut().request(name)
}
/// Check if the broadcast is closed, either because the publisher was dropped or called [Publisher::close].
pub fn is_closed(&self) -> Option<CacheError> {
self.state.lock().closed.as_ref().err().cloned()
}
/// Wait until if the broadcast is closed, either because the publisher was dropped or called [Publisher::close].
pub async fn closed(&self) -> CacheError {
loop {
let notify = {
let state = self.state.lock();
if let Some(err) = state.closed.as_ref().err() {
return err.clone();
}
state.changed()
};
notify.await;
}
}
}
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)
.finish()
}
}
// A handle that closes the broadcast when dropped:
// - when all Subscribers are dropped or
// - when Publisher and Unknown are dropped.
struct Dropped {
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();
}
}

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use thiserror::Error;
use crate::MoqError;
#[derive(Clone, Debug, Error)]
pub enum CacheError {
/// A clean termination, represented as error code 0.
/// This error is automatically used when publishers or subscribers are dropped without calling close.
#[error("closed")]
Closed,
/// An ANNOUNCE_RESET or SUBSCRIBE_RESET was sent by the publisher.
#[error("reset code={0:?}")]
Reset(u32),
/// An ANNOUNCE_STOP or SUBSCRIBE_STOP was sent by the subscriber.
#[error("stop")]
Stop,
/// The requested resource was not found.
#[error("not found")]
NotFound,
/// A resource already exists with that ID.
#[error("duplicate")]
Duplicate,
}
impl MoqError for CacheError {
/// An integer code that is sent over the wire.
fn code(&self) -> u32 {
match self {
Self::Closed => 0,
Self::Reset(code) => *code,
Self::Stop => 206,
Self::NotFound => 404,
Self::Duplicate => 409,
}
}
/// A reason that is sent over the wire.
fn reason(&self) -> String {
match self {
Self::Closed => "closed".to_owned(),
Self::Reset(code) => format!("reset code: {}", code),
Self::Stop => "stop".to_owned(),
Self::NotFound => "not found".to_owned(),
Self::Duplicate => "duplicate".to_owned(),
}
}
}

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//! 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<usize>,
}
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(())
}
}
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("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 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 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();
}
}

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//! Allows a publisher to push updates, automatically caching and fanning it out to any subscribers.
//!
//! The hierarchy is: [broadcast] -> [track] -> [segment] -> [fragment] -> [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;
pub(crate) mod watch;
pub(crate) use watch::*;
pub use error::*;

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moq-transport/src/cache/segment.rs vendored Normal file
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//! A segment is a stream of fragments with a header, split into a [Publisher] and [Subscriber] handle.
//!
//! A [Publisher] writes an ordered stream of fragments.
//! Each fragment can have a sequence number, allowing the subscriber to detect gaps fragments.
//!
//! A [Subscriber] reads an ordered stream of fragments.
//! The subscriber can be cloned, in which case each subscriber receives a copy of each fragment. (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 super::{fragment, 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 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: u32,
// Cache the segment for at most this long.
pub expires: Option<time::Duration>,
}
struct State {
// The data that has been received thus far.
fragments: Vec<fragment::Subscriber>,
// 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(())
}
}
impl Default for State {
fn default() -> Self {
Self {
fragments: Vec::new(),
closed: Ok(()),
}
}
}
impl fmt::Debug for State {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("State")
.field("fragments", &self.fragments)
.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 }
}
// Not public because it's a footgun.
pub(crate) fn push_fragment(
&mut self,
sequence: VarInt,
size: Option<usize>,
) -> Result<fragment::Publisher, CacheError> {
let (publisher, subscriber) = fragment::new(fragment::Info { sequence, size });
let mut state = self.state.lock_mut();
state.closed.clone()?;
state.fragments.push(subscriber);
Ok(publisher)
}
/// Write a fragment
pub fn fragment(&mut self, sequence: VarInt, size: usize) -> Result<fragment::Publisher, CacheError> {
self.push_fragment(sequence, Some(size))
}
/// Write the last fragment, which means size can be unknown.
pub fn final_fragment(mut self, sequence: VarInt) -> Result<fragment::Publisher, CacheError> {
self.push_fragment(sequence, None)
}
/// 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 fragment(&mut self) -> Result<Option<fragment::Subscriber>, CacheError> {
loop {
let notify = {
let state = self.state.lock();
if self.index < state.fragments.len() {
let fragment = state.fragments[self.index].clone();
self.index += 1;
return Ok(Some(fragment));
}
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();
}
}

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//! A track is a collection of semi-reliable and semi-ordered segments, split into a [Publisher] and [Subscriber] handle.
//!
//! A [Publisher] creates segments with a sequence number and priority.
//! The sequest number is used to determine the order of segments, while the priority is used to determine which segment to transmit first.
//! This may seem counter-intuitive, but is designed for live streaming where the newest segments may be higher priority.
//! A cloned [Publisher] can be used to create segments in parallel, but will error if a duplicate sequence number is used.
//!
//! A [Subscriber] may not receive all segments in order or at all.
//! These segments are meant to be transmitted over congested networks and the key to MoQ Tranport is to not block on them.
//! Segments will be cached for a potentially limited duration added to the unreliable nature.
//! A cloned [Subscriber] will receive a copy of all new segment going forward (fanout).
//!
//! The track is closed with [CacheError::Closed] when all publishers or subscribers are dropped.
use std::{collections::BinaryHeap, fmt, ops::Deref, sync::Arc, time};
use indexmap::IndexMap;
use super::{segment, CacheError, Watch};
use crate::VarInt;
/// Create a track with the given name.
pub fn new(name: &str) -> (Publisher, Subscriber) {
let state = Watch::new(State::default());
let info = Arc::new(Info { name: name.to_string() });
let publisher = Publisher::new(state.clone(), info.clone());
let subscriber = Subscriber::new(state, info);
(publisher, subscriber)
}
/// Static information about a track.
#[derive(Debug)]
pub struct Info {
pub name: String,
}
struct State {
// Store segments in received order so subscribers can detect changes.
// The key is the segment sequence, which could have gaps.
// A None value means the segment has expired.
lookup: IndexMap<VarInt, Option<segment::Subscriber>>,
// Store when segments will expire in a priority queue.
expires: BinaryHeap<SegmentExpiration>,
// The number of None entries removed from the start of the lookup.
pruned: usize,
// Set when the publisher is closed/dropped, or all subscribers are 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 insert(&mut self, segment: segment::Subscriber) -> Result<(), CacheError> {
self.closed.clone()?;
let entry = match self.lookup.entry(segment.sequence) {
indexmap::map::Entry::Occupied(_entry) => return Err(CacheError::Duplicate),
indexmap::map::Entry::Vacant(entry) => entry,
};
if let Some(expires) = segment.expires {
self.expires.push(SegmentExpiration {
sequence: segment.sequence,
expires: time::Instant::now() + expires,
});
}
entry.insert(Some(segment));
// Expire any existing segments on insert.
// This means if you don't insert then you won't expire... but it's probably fine since the cache won't grow.
// TODO Use a timer to expire segments at the correct time instead
self.expire();
Ok(())
}
// Try expiring any segments
pub fn expire(&mut self) {
let now = time::Instant::now();
while let Some(segment) = self.expires.peek() {
if segment.expires > now {
break;
}
// Update the entry to None while preserving the index.
match self.lookup.entry(segment.sequence) {
indexmap::map::Entry::Occupied(mut entry) => entry.insert(None),
indexmap::map::Entry::Vacant(_) => panic!("expired segment not found"),
};
self.expires.pop();
}
// Remove None entries from the start of the lookup.
while let Some((_, None)) = self.lookup.get_index(0) {
self.lookup.shift_remove_index(0);
self.pruned += 1;
}
}
}
impl Default for State {
fn default() -> Self {
Self {
lookup: Default::default(),
expires: Default::default(),
pruned: 0,
closed: Ok(()),
}
}
}
impl fmt::Debug for State {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("State")
.field("lookup", &self.lookup)
.field("pruned", &self.pruned)
.field("closed", &self.closed)
.finish()
}
}
/// Creates new segments for a track.
pub struct Publisher {
state: Watch<State>,
info: Arc<Info>,
_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 }
}
/// Insert a new segment.
pub fn insert_segment(&mut self, segment: segment::Subscriber) -> Result<(), CacheError> {
self.state.lock_mut().insert(segment)
}
/// Create an insert a segment with the given info.
pub fn create_segment(&mut self, info: segment::Info) -> Result<segment::Publisher, CacheError> {
let (publisher, subscriber) = segment::new(info);
self.insert_segment(subscriber)?;
Ok(publisher)
}
/// 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()
}
}
/// Receives new segments for a track.
#[derive(Clone)]
pub struct Subscriber {
state: Watch<State>,
info: Arc<Info>,
// The index of the next segment to return.
index: usize,
// If there are multiple segments to return, we put them in here to return them in priority order.
pending: BinaryHeap<SegmentPriority>,
// 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,
pending: Default::default(),
_dropped,
}
}
/// Block until the next segment arrives
pub async fn segment(&mut self) -> Result<Option<segment::Subscriber>, CacheError> {
loop {
let notify = {
let state = self.state.lock();
// Get our adjusted index, which could be negative if we've removed more broadcasts than read.
let mut index = self.index.saturating_sub(state.pruned);
// Push all new segments into a priority queue.
while index < state.lookup.len() {
let (_, segment) = state.lookup.get_index(index).unwrap();
// Skip None values (expired segments).
// TODO These might actually be expired, so we should check the expiration time.
if let Some(segment) = segment {
self.pending.push(SegmentPriority(segment.clone()));
}
index += 1;
}
self.index = state.pruned + index;
// Return the higher priority segment.
if let Some(segment) = self.pending.pop() {
return Ok(Some(segment.0));
}
// Otherwise check if we need to return an error.
match &state.closed {
Err(CacheError::Closed) => return Ok(None),
Err(err) => return Err(err.clone()),
Ok(()) => state.changed(),
}
};
notify.await
}
}
}
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()
}
}
// Closes the track on Drop.
struct Dropped {
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();
}
}
// Used to order segments by expiration time.
struct SegmentExpiration {
sequence: VarInt,
expires: time::Instant,
}
impl Ord for SegmentExpiration {
fn cmp(&self, other: &Self) -> std::cmp::Ordering {
// Reverse order so the earliest expiration is at the top of the heap.
other.expires.cmp(&self.expires)
}
}
impl PartialOrd for SegmentExpiration {
fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
Some(self.cmp(other))
}
}
impl PartialEq for SegmentExpiration {
fn eq(&self, other: &Self) -> bool {
self.expires == other.expires
}
}
impl Eq for SegmentExpiration {}
// Used to order segments by priority
#[derive(Clone)]
struct SegmentPriority(pub segment::Subscriber);
impl Ord for SegmentPriority {
fn cmp(&self, other: &Self) -> std::cmp::Ordering {
// Reverse order so the highest priority is at the top of the heap.
// TODO I let CodePilot generate this code so yolo
other.0.priority.cmp(&self.0.priority)
}
}
impl PartialOrd for SegmentPriority {
fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
Some(self.cmp(other))
}
}
impl PartialEq for SegmentPriority {
fn eq(&self, other: &Self) -> bool {
self.0.priority == other.0.priority
}
}
impl Eq for SegmentPriority {}

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moq-transport/src/cache/watch.rs vendored Normal file
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use std::{
fmt,
future::Future,
ops::{Deref, DerefMut},
pin::Pin,
sync::{Arc, Mutex, MutexGuard},
task,
};
struct State<T> {
value: T,
wakers: Vec<task::Waker>,
epoch: usize,
}
impl<T> State<T> {
pub fn new(value: T) -> Self {
Self {
value,
wakers: Vec::new(),
epoch: 0,
}
}
pub fn register(&mut self, waker: &task::Waker) {
self.wakers.retain(|existing| !existing.will_wake(waker));
self.wakers.push(waker.clone());
}
pub fn notify(&mut self) {
self.epoch += 1;
for waker in self.wakers.drain(..) {
waker.wake();
}
}
}
impl<T: Default> Default for State<T> {
fn default() -> Self {
Self::new(T::default())
}
}
impl<T: fmt::Debug> fmt::Debug for State<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.value.fmt(f)
}
}
pub struct Watch<T> {
state: Arc<Mutex<State<T>>>,
}
impl<T> Watch<T> {
pub fn new(initial: T) -> Self {
let state = Arc::new(Mutex::new(State::new(initial)));
Self { state }
}
pub fn lock(&self) -> WatchRef<T> {
WatchRef {
state: self.state.clone(),
lock: self.state.lock().unwrap(),
}
}
pub fn lock_mut(&self) -> WatchMut<T> {
WatchMut {
lock: self.state.lock().unwrap(),
}
}
}
impl<T> Clone for Watch<T> {
fn clone(&self) -> Self {
Self {
state: self.state.clone(),
}
}
}
impl<T: Default> Default for Watch<T> {
fn default() -> Self {
Self::new(T::default())
}
}
impl<T: fmt::Debug> fmt::Debug for Watch<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self.state.try_lock() {
Ok(lock) => lock.value.fmt(f),
Err(_) => write!(f, "<locked>"),
}
}
}
pub struct WatchRef<'a, T> {
state: Arc<Mutex<State<T>>>,
lock: MutexGuard<'a, State<T>>,
}
impl<'a, T> WatchRef<'a, T> {
// Release the lock and wait for a notification when next updated.
pub fn changed(self) -> WatchChanged<T> {
WatchChanged {
state: self.state,
epoch: self.lock.epoch,
}
}
// Upgrade to a mutable references that automatically calls notify on drop.
pub fn into_mut(self) -> WatchMut<'a, T> {
WatchMut { lock: self.lock }
}
}
impl<'a, T> Deref for WatchRef<'a, T> {
type Target = T;
fn deref(&self) -> &Self::Target {
&self.lock.value
}
}
impl<'a, T: fmt::Debug> fmt::Debug for WatchRef<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.lock.fmt(f)
}
}
pub struct WatchMut<'a, T> {
lock: MutexGuard<'a, State<T>>,
}
impl<'a, T> Deref for WatchMut<'a, T> {
type Target = T;
fn deref(&self) -> &Self::Target {
&self.lock.value
}
}
impl<'a, T> DerefMut for WatchMut<'a, T> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.lock.value
}
}
impl<'a, T> Drop for WatchMut<'a, T> {
fn drop(&mut self) {
self.lock.notify();
}
}
impl<'a, T: fmt::Debug> fmt::Debug for WatchMut<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.lock.fmt(f)
}
}
pub struct WatchChanged<T> {
state: Arc<Mutex<State<T>>>,
epoch: usize,
}
impl<T> Future for WatchChanged<T> {
type Output = ();
fn poll(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> task::Poll<Self::Output> {
// TODO is there an API we can make that doesn't drop this lock?
let mut state = self.state.lock().unwrap();
if state.epoch > self.epoch {
task::Poll::Ready(())
} else {
state.register(cx.waker());
task::Poll::Pending
}
}
}

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moq-transport/src/coding/decode.rs Normal file
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use super::{BoundsExceeded, VarInt};
use std::{io, str};
use thiserror::Error;
// I'm too lazy to add these trait bounds to every message type.
// 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)]
pub enum DecodeError {
#[error("unexpected end of buffer")]
UnexpectedEnd,
#[error("invalid string")]
InvalidString(#[from] str::Utf8Error),
#[error("invalid message: {0:?}")]
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,
}

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moq-transport/src/coding/encode.rs Normal file
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use super::BoundsExceeded;
use thiserror::Error;
// I'm too lazy to add these trait bounds to every message type.
// 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)]
pub enum EncodeError {
#[error("varint too large")]
BoundsExceeded(#[from] BoundsExceeded),
#[error("invalid value")]
InvalidValue,
#[error("i/o error: {0}")]
IoError(#[from] std::io::Error),
}

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moq-transport/src/coding/mod.rs Normal file
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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::*;

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moq-transport/src/coding/params.rs Normal file
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use std::io::Cursor;
use std::{cmp::max, collections::HashMap};
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use crate::coding::{AsyncRead, AsyncWrite, Decode, Encode};
use crate::{
coding::{DecodeError, EncodeError},
VarInt,
};
#[derive(Default, Debug, Clone)]
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);
}
let size = VarInt::decode(r).await?;
// Don't allocate the entire requested size to avoid a possible attack
// Instead, we allocate up to 1024 and keep appending as we read further.
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(Params(params))
}
}
#[async_trait::async_trait]
impl Encode for Params {
async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
VarInt::try_from(self.0.len())?.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(())
}
}
impl Params {
pub fn new() -> Self {
Self::default()
}
pub async fn set<P: Encode>(&mut self, kind: VarInt, p: P) -> Result<(), EncodeError> {
let mut value = Vec::new();
p.encode(&mut value).await?;
self.0.insert(kind, value);
Ok(())
}
pub fn has(&self, kind: VarInt) -> bool {
self.0.contains_key(&kind)
}
pub async fn get<P: Decode>(&mut self, kind: VarInt) -> Result<Option<P>, DecodeError> {
if let Some(value) = self.0.remove(&kind) {
let mut cursor = Cursor::new(value);
Ok(Some(P::decode(&mut cursor).await?))
} else {
Ok(None)
}
}
}

29
moq-transport/src/coding/string.rs Normal file
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use std::cmp::min;
use crate::coding::{AsyncRead, AsyncWrite};
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use crate::VarInt;
use super::{Decode, DecodeError, Encode, EncodeError};
#[async_trait::async_trait]
impl Encode for String {
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(self.as_ref()).await?;
Ok(())
}
}
#[async_trait::async_trait]
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)
}
}

232
moq-transport/src/coding/varint.rs Normal file
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// Based on quinn-proto
// https://github.com/quinn-rs/quinn/blob/main/quinn-proto/src/varint.rs
// Licensed via Apache 2.0 and MIT
use std::convert::{TryFrom, TryInto};
use std::fmt;
use crate::coding::{AsyncRead, AsyncWrite};
use thiserror::Error;
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use super::{Decode, DecodeError, Encode, EncodeError};
#[derive(Debug, Copy, Clone, Eq, PartialEq, Error)]
#[error("value out of range")]
pub struct BoundsExceeded;
/// An integer less than 2^62
///
/// Values of this type are suitable for encoding as QUIC variable-length integer.
// It would be neat if we could express to Rust that the top two bits are available for use as enum
// discriminants
#[derive(Default, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct VarInt(u64);
impl VarInt {
/// The largest possible value.
pub const MAX: Self = Self((1 << 62) - 1);
/// The smallest possible value.
pub const ZERO: Self = Self(0);
/// Construct a `VarInt` infallibly using the largest available type.
/// Larger values need to use `try_from` instead.
pub const fn from_u32(x: u32) -> Self {
Self(x as u64)
}
/// Extract the integer value
pub const fn into_inner(self) -> u64 {
self.0
}
}
impl From<VarInt> for u64 {
fn from(x: VarInt) -> Self {
x.0
}
}
impl From<VarInt> for usize {
fn from(x: VarInt) -> Self {
x.0 as usize
}
}
impl From<VarInt> for u128 {
fn from(x: VarInt) -> Self {
x.0 as u128
}
}
impl From<u8> for VarInt {
fn from(x: u8) -> Self {
Self(x.into())
}
}
impl From<u16> for VarInt {
fn from(x: u16) -> Self {
Self(x.into())
}
}
impl From<u32> for VarInt {
fn from(x: u32) -> Self {
Self(x.into())
}
}
impl TryFrom<u64> for VarInt {
type Error = BoundsExceeded;
/// Succeeds iff `x` < 2^62
fn try_from(x: u64) -> Result<Self, BoundsExceeded> {
if x <= Self::MAX.into_inner() {
Ok(Self(x))
} else {
Err(BoundsExceeded)
}
}
}
impl TryFrom<u128> for VarInt {
type Error = BoundsExceeded;
/// Succeeds iff `x` < 2^62
fn try_from(x: u128) -> Result<Self, BoundsExceeded> {
if x <= Self::MAX.into() {
Ok(Self(x as u64))
} else {
Err(BoundsExceeded)
}
}
}
impl TryFrom<usize> for VarInt {
type Error = BoundsExceeded;
/// Succeeds iff `x` < 2^62
fn try_from(x: usize) -> Result<Self, BoundsExceeded> {
Self::try_from(x as u64)
}
}
impl TryFrom<VarInt> for u32 {
type Error = BoundsExceeded;
/// Succeeds iff `x` < 2^32
fn try_from(x: VarInt) -> Result<Self, BoundsExceeded> {
if x.0 <= u32::MAX.into() {
Ok(x.0 as u32)
} else {
Err(BoundsExceeded)
}
}
}
impl TryFrom<VarInt> for u16 {
type Error = BoundsExceeded;
/// Succeeds iff `x` < 2^16
fn try_from(x: VarInt) -> Result<Self, BoundsExceeded> {
if x.0 <= u16::MAX.into() {
Ok(x.0 as u16)
} else {
Err(BoundsExceeded)
}
}
}
impl TryFrom<VarInt> for u8 {
type Error = BoundsExceeded;
/// Succeeds iff `x` < 2^8
fn try_from(x: VarInt) -> Result<Self, BoundsExceeded> {
if x.0 <= u8::MAX.into() {
Ok(x.0 as u8)
} else {
Err(BoundsExceeded)
}
}
}
impl fmt::Debug for VarInt {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.0.fmt(f)
}
}
impl fmt::Display for VarInt {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.0.fmt(f)
}
}
#[async_trait::async_trait]
impl Decode for VarInt {
/// Decode a varint from the given reader.
async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
let b = r.read_u8().await?;
Self::decode_byte(b, r).await
}
}
impl VarInt {
/// 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]),
0b01 => {
r.read_exact(buf[1..2].as_mut()).await?;
u64::from(u16::from_be_bytes(buf[..2].try_into().unwrap()))
}
0b10 => {
r.read_exact(buf[1..4].as_mut()).await?;
u64::from(u32::from_be_bytes(buf[..4].try_into().unwrap()))
}
0b11 => {
r.read_exact(buf[1..8].as_mut()).await?;
u64::from_be_bytes(buf)
}
_ => unreachable!(),
};
Ok(Self(x))
}
}
#[async_trait::async_trait]
impl Encode for VarInt {
/// Encode a varint to the given writer.
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?;
} else if x < 2u64.pow(14) {
w.write_u16(0b01 << 14 | x as u16).await?;
} else if x < 2u64.pow(30) {
w.write_u32(0b10 << 30 | x as u32).await?;
} else if x < 2u64.pow(62) {
w.write_u64(0b11 << 62 | x).await?;
} else {
unreachable!("malformed VarInt");
}
Ok(())
}
}
// This is a fork of quinn::VarInt.
impl From<quinn::VarInt> for VarInt {
fn from(v: quinn::VarInt) -> Self {
Self(v.into_inner())
}
}

7
moq-transport/src/error.rs Normal file
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pub trait MoqError {
/// An integer code that is sent over the wire.
fn code(&self) -> u32;
/// An optional reason sometimes sent over the wire.
fn reason(&self) -> String;
}

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moq-transport/src/lib.rs Normal file
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//! An implementation of the MoQ Transport protocol.
//!
//! MoQ Transport is a pub/sub protocol over QUIC.
//! While originally designed for live media, MoQ Transport is generic and can be used for other live applications.
//! 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.
//!
//! This implementation has some required extensions until the draft stablizes. See: [Extensions](crate::setup::Extensions)
mod coding;
mod error;
pub mod cache;
pub mod message;
pub mod session;
pub mod setup;
pub use coding::VarInt;
pub use error::MoqError;

30
moq-transport/src/message/announce.rs Normal file
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use crate::coding::{Decode, DecodeError, Encode, EncodeError, Params};
use crate::coding::{AsyncRead, AsyncWrite};
use crate::setup::Extensions;
/// Sent by the publisher to announce the availability of a group of tracks.
#[derive(Clone, Debug)]
pub struct Announce {
/// The track namespace
pub namespace: String,
/// Optional parameters
pub params: Params,
}
impl Announce {
pub async fn decode<R: AsyncRead>(r: &mut R, _ext: &Extensions) -> Result<Self, DecodeError> {
let namespace = String::decode(r).await?;
let params = Params::decode(r).await?;
Ok(Self { namespace, params })
}
pub async fn encode<W: AsyncWrite>(&self, w: &mut W, _ext: &Extensions) -> Result<(), EncodeError> {
self.namespace.encode(w).await?;
self.params.encode(w).await?;
Ok(())
}
}

23
moq-transport/src/message/announce_ok.rs Normal file
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use crate::{
coding::{AsyncRead, AsyncWrite, Decode, DecodeError, Encode, EncodeError},
setup::Extensions,
};
/// Sent by the subscriber to accept an Announce.
#[derive(Clone, Debug)]
pub struct AnnounceOk {
// Echo back the namespace that was announced.
// TODO Propose using an ID to save bytes.
pub namespace: String,
}
impl AnnounceOk {
pub async fn decode<R: AsyncRead>(r: &mut R, _ext: &Extensions) -> Result<Self, DecodeError> {
let namespace = String::decode(r).await?;
Ok(Self { namespace })
}
pub async fn encode<W: AsyncWrite>(&self, w: &mut W, _ext: &Extensions) -> Result<(), EncodeError> {
self.namespace.encode(w).await
}
}

39
moq-transport/src/message/announce_reset.rs Normal file
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use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
use crate::coding::{AsyncRead, AsyncWrite};
use crate::setup::Extensions;
/// Sent by the subscriber to reject an Announce.
#[derive(Clone, Debug)]
pub struct AnnounceError {
// Echo back the namespace that was reset
pub namespace: String,
// An error code.
pub code: u32,
// An optional, human-readable reason.
pub reason: String,
}
impl AnnounceError {
pub async fn decode<R: AsyncRead>(r: &mut R, _ext: &Extensions) -> Result<Self, DecodeError> {
let namespace = String::decode(r).await?;
let code = VarInt::decode(r).await?.try_into()?;
let reason = String::decode(r).await?;
Ok(Self {
namespace,
code,
reason,
})
}
pub async fn encode<W: AsyncWrite>(&self, w: &mut W, _ext: &Extensions) -> Result<(), EncodeError> {
self.namespace.encode(w).await?;
VarInt::from_u32(self.code).encode(w).await?;
self.reason.encode(w).await?;
Ok(())
}
}

21
moq-transport/src/message/go_away.rs Normal file
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use crate::coding::{Decode, DecodeError, Encode, EncodeError};
use crate::coding::{AsyncRead, AsyncWrite};
use crate::setup::Extensions;
/// Sent by the server to indicate that the client should connect to a different server.
#[derive(Clone, Debug)]
pub struct GoAway {
pub url: String,
}
impl GoAway {
pub async fn decode<R: AsyncRead>(r: &mut R, _ext: &Extensions) -> Result<Self, DecodeError> {
let url = String::decode(r).await?;
Ok(Self { url })
}
pub async fn encode<W: AsyncWrite>(&self, w: &mut W, _ext: &Extensions) -> Result<(), EncodeError> {
self.url.encode(w).await
}
}

160
moq-transport/src/message/mod.rs Normal file
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//! Low-level message sent over the wire, as defined in the specification.
//!
//! All of these messages are sent over a bidirectional QUIC stream.
//! This introduces some head-of-line blocking but preserves ordering.
//! The only exception are OBJECT "messages", which are sent over dedicated QUIC streams.
//!
//! Messages sent by the publisher:
//! - [Announce]
//! - [Unannounce]
//! - [SubscribeOk]
//! - [SubscribeError]
//! - [SubscribeReset]
//! - [Object]
//!
//! Messages sent by the subscriber:
//! - [Subscribe]
//! - [Unsubscribe]
//! - [AnnounceOk]
//! - [AnnounceError]
//!
//! Example flow:
//! ```test
//! -> ANNOUNCE namespace="foo"
//! <- ANNOUNCE_OK namespace="foo"
//! <- SUBSCRIBE id=0 namespace="foo" name="bar"
//! -> SUBSCRIBE_OK id=0
//! -> OBJECT id=0 sequence=69 priority=4 expires=30
//! -> OBJECT id=0 sequence=70 priority=4 expires=30
//! -> OBJECT id=0 sequence=70 priority=4 expires=30
//! <- SUBSCRIBE_STOP id=0
//! -> SUBSCRIBE_RESET id=0 code=206 reason="closed by peer"
//! ```
mod announce;
mod announce_ok;
mod announce_reset;
mod go_away;
mod object;
mod subscribe;
mod subscribe_error;
mod subscribe_fin;
mod subscribe_ok;
mod subscribe_reset;
mod unannounce;
mod unsubscribe;
pub use announce::*;
pub use announce_ok::*;
pub use announce_reset::*;
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 unannounce::*;
pub use unsubscribe::*;
use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
use std::fmt;
use crate::coding::{AsyncRead, AsyncWrite};
use crate::setup::Extensions;
// Use a macro to generate the message types rather than copy-paste.
// This implements a decode/encode method that uses the specified type.
macro_rules! message_types {
{$($name:ident = $val:expr,)*} => {
/// All supported message types.
#[derive(Clone)]
pub enum Message {
$($name($name)),*
}
impl Message {
pub async fn decode<R: AsyncRead>(r: &mut R, ext: &Extensions) -> Result<Self, DecodeError> {
let t = VarInt::decode(r).await?;
match t.into_inner() {
$($val => {
let msg = $name::decode(r, ext).await?;
Ok(Self::$name(msg))
})*
_ => Err(DecodeError::InvalidMessage(t)),
}
}
pub async fn encode<W: AsyncWrite>(&self, w: &mut W, ext: &Extensions) -> Result<(), EncodeError> {
match self {
$(Self::$name(ref m) => {
VarInt::from_u32($val).encode(w).await?;
m.encode(w, ext).await
},)*
}
}
pub fn id(&self) -> VarInt {
match self {
$(Self::$name(_) => {
VarInt::from_u32($val)
},)*
}
}
pub fn name(&self) -> &'static str {
match self {
$(Self::$name(_) => {
stringify!($name)
},)*
}
}
}
$(impl From<$name> for Message {
fn from(m: $name) -> Self {
Message::$name(m)
}
})*
impl fmt::Debug for Message {
// Delegate to the message formatter
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
$(Self::$name(ref m) => m.fmt(f),)*
}
}
}
}
}
// Each message is prefixed with the given VarInt type.
message_types! {
// NOTE: Object and Setup are in other modules.
// Object = 0x0
// ObjectUnbounded = 0x2
// SetupClient = 0x40
// SetupServer = 0x41
// SUBSCRIBE family, sent by subscriber
Subscribe = 0x3,
Unsubscribe = 0xa,
// SUBSCRIBE family, sent by publisher
SubscribeOk = 0x4,
SubscribeError = 0x5,
SubscribeFin = 0xb,
SubscribeReset = 0xc,
// ANNOUNCE family, sent by publisher
Announce = 0x6,
Unannounce = 0x9,
// ANNOUNCE family, sent by subscriber
AnnounceOk = 0x7,
AnnounceError = 0x8,
// Misc
GoAway = 0x10,
}

108
moq-transport/src/message/object.rs Normal file
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use std::{io, time};
use tokio::io::AsyncReadExt;
use crate::coding::{AsyncRead, AsyncWrite};
use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
use crate::setup;
/// Sent by the publisher as the header of each data stream.
#[derive(Clone, Debug)]
pub struct Object {
// An ID for this track.
// Proposal: https://github.com/moq-wg/moq-transport/issues/209
pub track: VarInt,
// The sequence number within the track.
pub group: VarInt,
// The sequence number within the group.
pub sequence: VarInt,
// The priority, where **smaller** values are sent first.
pub priority: u32,
// 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, extensions: &setup::Extensions) -> Result<Self, DecodeError> {
// Try reading the first byte, returning a special error if the stream naturally ended.
let typ = match r.read_u8().await {
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()),
};
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 = VarInt::decode(r).await?.try_into()?;
let expires = match extensions.object_expires {
true => match VarInt::decode(r).await?.into_inner() {
0 => None,
secs => Some(time::Duration::from_secs(secs)),
},
false => None,
};
// 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, extensions: &setup::Extensions) -> Result<(), EncodeError> {
// 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?;
VarInt::from_u32(self.priority).encode(w).await?;
// Round up if there's any decimal points.
let expires = match self.expires {
None => 0,
Some(time::Duration::ZERO) => return Err(EncodeError::InvalidValue), // there's no way of expressing zero currently.
Some(expires) if expires.subsec_nanos() > 0 => expires.as_secs() + 1,
Some(expires) => expires.as_secs(),
};
if extensions.object_expires {
VarInt::try_from(expires)?.encode(w).await?;
}
if let Some(size) = self.size {
size.encode(w).await?;
}
Ok(())
}
}

142
moq-transport/src/message/subscribe.rs Normal file
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use crate::coding::{Decode, DecodeError, Encode, EncodeError, Params, VarInt};
use crate::coding::{AsyncRead, AsyncWrite};
use crate::setup::Extensions;
/// Sent by the subscriber to request all future objects for the given track.
///
/// 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.
// Proposal: https://github.com/moq-wg/moq-transport/issues/209
pub id: VarInt,
/// The track namespace.
///
/// Must be None if `extensions.subscribe_split` is false.
pub namespace: Option<String>,
/// 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, ext: &Extensions) -> Result<Self, DecodeError> {
let id = VarInt::decode(r).await?;
let namespace = match ext.subscribe_split {
true => Some(String::decode(r).await?),
false => None,
};
let name = String::decode(r).await?;
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,
})
}
pub async fn encode<W: AsyncWrite>(&self, w: &mut W, ext: &Extensions) -> Result<(), EncodeError> {
self.id.encode(w).await?;
if self.namespace.is_some() != ext.subscribe_split {
panic!("namespace must be None if subscribe_split is false");
}
if ext.subscribe_split {
self.namespace.as_ref().unwrap().encode(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(())
}
}

36
moq-transport/src/message/subscribe_error.rs Normal file
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use crate::coding::{AsyncRead, AsyncWrite};
use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
use crate::setup::Extensions;
/// 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, _ext: &Extensions) -> 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, _ext: &Extensions) -> Result<(), EncodeError> {
self.id.encode(w).await?;
VarInt::from_u32(self.code).encode(w).await?;
self.reason.encode(w).await?;
Ok(())
}
}

37
moq-transport/src/message/subscribe_fin.rs Normal file
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use crate::coding::{AsyncRead, AsyncWrite};
use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
use crate::setup::Extensions;
/// 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, _ext: &Extensions) -> 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, _ext: &Extensions) -> Result<(), EncodeError> {
self.id.encode(w).await?;
self.final_group.encode(w).await?;
self.final_object.encode(w).await?;
Ok(())
}
}

31
moq-transport/src/message/subscribe_ok.rs Normal file
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use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
use crate::coding::{AsyncRead, AsyncWrite};
use crate::setup::Extensions;
/// Sent by the publisher to accept a Subscribe.
#[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.
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, _ext: &Extensions) -> Result<Self, DecodeError> {
let id = VarInt::decode(r).await?;
let expires = VarInt::decode(r).await?;
Ok(Self { id, expires })
}
}
impl SubscribeOk {
pub async fn encode<W: AsyncWrite>(&self, w: &mut W, _ext: &Extensions) -> Result<(), EncodeError> {
self.id.encode(w).await?;
self.expires.encode(w).await?;
Ok(())
}
}

50
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use crate::coding::{AsyncRead, AsyncWrite};
use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
use crate::setup::Extensions;
/// 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.
pub id: VarInt,
/// An error code.
pub code: u32,
/// 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, _ext: &Extensions) -> Result<Self, DecodeError> {
let id = VarInt::decode(r).await?;
let code = VarInt::decode(r).await?.try_into()?;
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,
final_group,
final_object,
})
}
pub async fn encode<W: AsyncWrite>(&self, w: &mut W, _ext: &Extensions) -> Result<(), EncodeError> {
self.id.encode(w).await?;
VarInt::from_u32(self.code).encode(w).await?;
self.reason.encode(w).await?;
self.final_group.encode(w).await?;
self.final_object.encode(w).await?;
Ok(())
}
}

25
moq-transport/src/message/unannounce.rs Normal file
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use crate::coding::{Decode, DecodeError, Encode, EncodeError};
use crate::coding::{AsyncRead, AsyncWrite};
use crate::setup::Extensions;
/// Sent by the publisher to terminate an Announce.
#[derive(Clone, Debug)]
pub struct Unannounce {
// Echo back the namespace that was reset
pub namespace: String,
}
impl Unannounce {
pub async fn decode<R: AsyncRead>(r: &mut R, _ext: &Extensions) -> Result<Self, DecodeError> {
let namespace = String::decode(r).await?;
Ok(Self { namespace })
}
pub async fn encode<W: AsyncWrite>(&self, w: &mut W, _ext: &Extensions) -> Result<(), EncodeError> {
self.namespace.encode(w).await?;
Ok(())
}
}

27
moq-transport/src/message/unsubscribe.rs Normal file
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use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
use crate::coding::{AsyncRead, AsyncWrite};
use crate::setup::Extensions;
/// Sent by the subscriber to terminate a Subscribe.
#[derive(Clone, Debug)]
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 Unsubscribe {
pub async fn decode<R: AsyncRead>(r: &mut R, _ext: &Extensions) -> Result<Self, DecodeError> {
let id = VarInt::decode(r).await?;
Ok(Self { id })
}
}
impl Unsubscribe {
pub async fn encode<W: AsyncWrite>(&self, w: &mut W, _ext: &Extensions) -> Result<(), EncodeError> {
self.id.encode(w).await?;
Ok(())
}
}

76
moq-transport/src/session/client.rs Normal file
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use super::{Control, Publisher, SessionError, Subscriber};
use crate::{cache::broadcast, setup};
use webtransport_quinn::Session;
/// An endpoint that connects to a URL to publish and/or consume live streams.
pub struct Client {}
impl Client {
/// Connect using an established WebTransport session, performing the MoQ handshake as a publisher.
pub async fn publisher(session: Session, source: broadcast::Subscriber) -> Result<Publisher, SessionError> {
let control = Self::send_setup(&session, setup::Role::Publisher).await?;
let publisher = Publisher::new(session, control, source);
Ok(publisher)
}
/// Connect using an established WebTransport session, performing the MoQ handshake as a subscriber.
pub async fn subscriber(session: Session, source: broadcast::Publisher) -> Result<Subscriber, SessionError> {
let control = Self::send_setup(&session, setup::Role::Subscriber).await?;
let subscriber = Subscriber::new(session, control, source);
Ok(subscriber)
}
// TODO support performing both roles
/*
pub async fn connect(self) -> anyhow::Result<(Publisher, Subscriber)> {
self.connect_role(setup::Role::Both).await
}
*/
async fn send_setup(session: &Session, role: setup::Role) -> Result<Control, SessionError> {
let mut control = session.open_bi().await?;
let versions: setup::Versions = [setup::Version::DRAFT_01, setup::Version::KIXEL_01].into();
let client = setup::Client {
role,
versions: versions.clone(),
params: Default::default(),
// Offer all extensions
extensions: setup::Extensions {
object_expires: true,
subscriber_id: true,
subscribe_split: true,
},
};
log::debug!("sending client SETUP: {:?}", client);
client.encode(&mut control.0).await?;
let mut server = setup::Server::decode(&mut control.1).await?;
log::debug!("received server SETUP: {:?}", server);
match server.version {
setup::Version::DRAFT_01 => {
// We always require this extension
server.extensions.require_subscriber_id()?;
if server.role.is_publisher() {
// We only require object expires if we're a subscriber, so we don't cache objects indefinitely.
server.extensions.require_object_expires()?;
}
}
setup::Version::KIXEL_01 => {
// KIXEL_01 didn't support extensions; all were enabled.
server.extensions = client.extensions.clone()
}
_ => return Err(SessionError::Version(versions, [server.version].into())),
}
let control = Control::new(control.0, control.1, server.extensions);
Ok(control)
}
}

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moq-transport/src/session/control.rs Normal file
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// A helper class to guard sending control messages behind a Mutex.
use std::{fmt, sync::Arc};
use tokio::sync::Mutex;
use webtransport_quinn::{RecvStream, SendStream};
use super::SessionError;
use crate::{message::Message, setup::Extensions};
#[derive(Debug, Clone)]
pub(crate) struct Control {
send: Arc<Mutex<SendStream>>,
recv: Arc<Mutex<RecvStream>>,
pub ext: Extensions,
}
impl Control {
pub fn new(send: SendStream, recv: RecvStream, ext: Extensions) -> Self {
Self {
send: Arc::new(Mutex::new(send)),
recv: Arc::new(Mutex::new(recv)),
ext,
}
}
pub async fn send<T: Into<Message> + fmt::Debug>(&self, msg: T) -> Result<(), SessionError> {
let mut stream = self.send.lock().await;
log::info!("sending message: {:?}", msg);
msg.into()
.encode(&mut *stream, &self.ext)
.await
.map_err(|e| SessionError::Unknown(e.to_string()))?;
Ok(())
}
// It's likely a mistake to call this from two different tasks, but it's easier to just support it.
pub async fn recv(&self) -> Result<Message, SessionError> {
let mut stream = self.recv.lock().await;
let msg = Message::decode(&mut *stream, &self.ext)
.await
.map_err(|e| SessionError::Unknown(e.to_string()))?;
Ok(msg)
}
}

107
moq-transport/src/session/error.rs Normal file
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use crate::{cache, coding, setup, MoqError, VarInt};
#[derive(thiserror::Error, Debug)]
pub enum SessionError {
#[error("webtransport error: {0}")]
Session(#[from] webtransport_quinn::SessionError),
#[error("cache error: {0}")]
Cache(#[from] cache::CacheError),
#[error("encode error: {0}")]
Encode(#[from] coding::EncodeError),
#[error("decode error: {0}")]
Decode(#[from] coding::DecodeError),
#[error("unsupported versions: client={0:?} server={1:?}")]
Version(setup::Versions, setup::Versions),
#[error("incompatible roles: client={0:?} server={1:?}")]
RoleIncompatible(setup::Role, setup::Role),
/// An error occured while reading from the QUIC stream.
#[error("failed to read from stream: {0}")]
Read(#[from] webtransport_quinn::ReadError),
/// An error occured while writing to the QUIC stream.
#[error("failed to write to stream: {0}")]
Write(#[from] webtransport_quinn::WriteError),
/// The role negiotiated in the handshake was violated. For example, a publisher sent a SUBSCRIBE, or a subscriber sent an OBJECT.
#[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),
/// A required extension was not offered.
#[error("required extension not offered: {0:?}")]
RequiredExtension(VarInt),
/// Some VarInt was too large and we were too lazy to handle it
#[error("varint bounds exceeded")]
BoundsExceeded(#[from] coding::BoundsExceeded),
/// An unclassified error because I'm lazy. TODO classify these errors
#[error("unknown error: {0}")]
Unknown(String),
}
impl MoqError for SessionError {
/// An integer code that is sent over the wire.
fn code(&self) -> u32 {
match self {
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::Encode(_) => 500,
Self::Decode(_) => 500,
Self::InvalidPriority(_) => 400,
Self::InvalidSize(_) => 400,
Self::RequiredExtension(_) => 426,
Self::BoundsExceeded(_) => 500,
}
}
/// A reason that is sent over the wire.
fn reason(&self) -> String {
match self {
Self::Cache(err) => err.reason(),
Self::RoleViolation(kind) => format!("role violation for message type {:?}", kind),
Self::RoleIncompatible(client, server) => {
format!(
"role incompatible: client wanted {:?} but server wanted {:?}",
client, server
)
}
Self::Read(err) => format!("read error: {}", err),
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),
Self::RequiredExtension(id) => format!("required extension was missing: {:?}", id),
Self::BoundsExceeded(_) => "varint bounds exceeded".to_string(),
}
}
}

27
moq-transport/src/session/mod.rs Normal file
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//! A MoQ Transport session, on top of a WebTransport session, on top of a QUIC connection.
//!
//! The handshake is relatively simple but split into different steps.
//! All of these handshakes slightly differ depending on if the endpoint is a client or server.
//! 1. Complete the QUIC handhake.
//! 2. Complete the WebTransport handshake.
//! 3. Complete the MoQ handshake.
//!
//! Use [Client] or [Server] for the MoQ handshake depending on the endpoint.
//! Then, decide if you want to create a [Publisher] or [Subscriber], or both (TODO).
//!
//! A [Publisher] can announce broadcasts, which will automatically be served over the network.
//! A [Subscriber] can subscribe to broadcasts, which will automatically be served over the network.
mod client;
mod control;
mod error;
mod publisher;
mod server;
mod subscriber;
pub use client::*;
pub(crate) use control::*;
pub use error::*;
pub use publisher::*;
pub use server::*;
pub use subscriber::*;

237
moq-transport/src/session/publisher.rs Normal file
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use std::{
collections::{hash_map, HashMap},
sync::{Arc, Mutex},
};
use tokio::task::AbortHandle;
use webtransport_quinn::Session;
use crate::{
cache::{broadcast, segment, track, CacheError},
message,
message::Message,
MoqError, VarInt,
};
use super::{Control, SessionError};
/// Serves broadcasts over the network, automatically handling subscriptions and caching.
// TODO Clone specific fields when a task actually needs it.
#[derive(Clone, Debug)]
pub struct Publisher {
// A map of active subscriptions, containing an abort handle to cancel them.
subscribes: Arc<Mutex<HashMap<VarInt, AbortHandle>>>,
webtransport: Session,
control: Control,
source: broadcast::Subscriber,
}
impl Publisher {
pub(crate) fn new(webtransport: Session, control: Control, source: broadcast::Subscriber) -> Self {
Self {
webtransport,
control,
subscribes: Default::default(),
source,
}
}
// TODO Serve a broadcast without sending an ANNOUNCE.
// fn serve(&mut self, broadcast: broadcast::Subscriber) -> Result<(), SessionError> {
// TODO Wait until the next subscribe that doesn't route to an ANNOUNCE.
// pub async fn subscribed(&mut self) -> Result<track::Producer, SessionError> {
pub async fn run(mut self) -> Result<(), SessionError> {
let res = self.run_inner().await;
// Terminate all active subscribes on error.
self.subscribes
.lock()
.unwrap()
.drain()
.for_each(|(_, abort)| abort.abort());
res
}
pub async fn run_inner(&mut self) -> Result<(), SessionError> {
loop {
tokio::select! {
stream = self.webtransport.accept_uni() => {
stream?;
return Err(SessionError::RoleViolation(VarInt::ZERO));
}
// NOTE: this is not cancel safe, but it's fine since the other branchs are fatal.
msg = self.control.recv() => {
let msg = msg?;
log::info!("message received: {:?}", msg);
if let Err(err) = self.recv_message(&msg).await {
log::warn!("message error: {:?} {:?}", err, msg);
}
},
// No more broadcasts are available.
err = self.source.closed() => {
self.webtransport.close(err.code(), err.reason().as_bytes());
return Ok(());
},
}
}
}
async fn recv_message(&mut self, msg: &Message) -> Result<(), SessionError> {
match msg {
Message::AnnounceOk(msg) => self.recv_announce_ok(msg).await,
Message::AnnounceError(msg) => self.recv_announce_error(msg).await,
Message::Subscribe(msg) => self.recv_subscribe(msg).await,
Message::Unsubscribe(msg) => self.recv_unsubscribe(msg).await,
_ => Err(SessionError::RoleViolation(msg.id())),
}
}
async fn recv_announce_ok(&mut self, _msg: &message::AnnounceOk) -> Result<(), SessionError> {
// We didn't send an announce.
Err(CacheError::NotFound.into())
}
async fn recv_announce_error(&mut self, _msg: &message::AnnounceError) -> Result<(), SessionError> {
// We didn't send an announce.
Err(CacheError::NotFound.into())
}
async fn recv_subscribe(&mut self, msg: &message::Subscribe) -> Result<(), SessionError> {
// Assume that the subscribe ID is unique for now.
let abort = match self.start_subscribe(msg.clone()) {
Ok(abort) => abort,
Err(err) => return self.reset_subscribe(msg.id, err).await,
};
// Insert the abort handle into the lookup table.
match self.subscribes.lock().unwrap().entry(msg.id) {
hash_map::Entry::Occupied(_) => return Err(CacheError::Duplicate.into()), // TODO fatal, because we already started the task
hash_map::Entry::Vacant(entry) => entry.insert(abort),
};
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(),
// 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
}
fn start_subscribe(&mut self, msg: message::Subscribe) -> Result<AbortHandle, SessionError> {
// We currently don't use the namespace field in SUBSCRIBE
// Make sure the namespace is empty if it's provided.
if msg.namespace.as_ref().map_or(false, |namespace| !namespace.is_empty()) {
return Err(CacheError::NotFound.into());
}
let mut track = self.source.get_track(&msg.name)?;
// TODO only clone the fields we need
let mut this = self.clone();
let handle = tokio::spawn(async move {
log::info!("serving track: name={}", track.name);
let res = this.run_subscribe(msg.id, &mut track).await;
if let Err(err) = &res {
log::warn!("failed to serve track: name={} err={:#?}", track.name, err);
}
// Make sure we send a reset at the end.
let err = res.err().unwrap_or(CacheError::Closed.into());
this.reset_subscribe(msg.id, err).await.ok();
// We're all done, so clean up the abort handle.
this.subscribes.lock().unwrap().remove(&msg.id);
});
Ok(handle.abort_handle())
}
async fn run_subscribe(&self, id: VarInt, track: &mut track::Subscriber) -> Result<(), SessionError> {
// TODO add an Ok method to track::Publisher so we can send SUBSCRIBE_OK
while let Some(mut segment) = track.segment().await? {
// TODO only clone the fields we need
let this = self.clone();
tokio::spawn(async move {
if let Err(err) = this.run_segment(id, &mut segment).await {
log::warn!("failed to serve segment: {:?}", err)
}
});
}
Ok(())
}
async fn run_segment(&self, id: VarInt, segment: &mut segment::Subscriber) -> Result<(), SessionError> {
log::trace!("serving group: {:?}", segment);
let mut stream = self.webtransport.open_uni().await?;
// 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.fragment().await? {
log::trace!("serving fragment: {:?}", fragment);
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.map(VarInt::try_from).transpose()?,
};
object
.encode(&mut stream, &self.control.ext)
.await
.map_err(|e| SessionError::Unknown(e.to_string()))?;
while let Some(chunk) = fragment.chunk().await? {
//log::trace!("writing chunk: {:?}", chunk);
stream.write_all(&chunk).await?;
}
}
Ok(())
}
async fn recv_unsubscribe(&mut self, msg: &message::Unsubscribe) -> Result<(), SessionError> {
let abort = self
.subscribes
.lock()
.unwrap()
.remove(&msg.id)
.ok_or(CacheError::NotFound)?;
abort.abort();
self.reset_subscribe(msg.id, CacheError::Stop).await
}
}

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moq-transport/src/session/server.rs Normal file
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use super::{Control, Publisher, SessionError, Subscriber};
use crate::{cache::broadcast, setup};
use webtransport_quinn::{RecvStream, SendStream, Session};
/// An endpoint that accepts connections, publishing and/or consuming live streams.
pub struct Server {}
impl Server {
/// Accept an established Webtransport session, performing the MoQ handshake.
///
/// This returns a [Request] half-way through the handshake that allows the application to accept or deny the session.
pub async fn accept(session: Session) -> Result<Request, SessionError> {
let mut control = session.accept_bi().await?;
let mut client = setup::Client::decode(&mut control.1).await?;
log::debug!("received client SETUP: {:?}", client);
if client.versions.contains(&setup::Version::DRAFT_01) {
// We always require subscriber ID.
client.extensions.require_subscriber_id()?;
// We require OBJECT_EXPIRES for publishers only.
if client.role.is_publisher() {
client.extensions.require_object_expires()?;
}
// We don't require SUBSCRIBE_SPLIT since it's easy enough to support, but it's clearly an oversight.
// client.extensions.require(&Extension::SUBSCRIBE_SPLIT)?;
} else if client.versions.contains(&setup::Version::KIXEL_01) {
// Extensions didn't exist in KIXEL_01, so we set them manually.
client.extensions = setup::Extensions {
object_expires: true,
subscriber_id: true,
subscribe_split: true,
};
} else {
return Err(SessionError::Version(
client.versions,
[setup::Version::DRAFT_01, setup::Version::KIXEL_01].into(),
));
}
Ok(Request {
session,
client,
control,
})
}
}
/// A partially complete MoQ Transport handshake.
pub struct Request {
session: Session,
client: setup::Client,
control: (SendStream, RecvStream),
}
impl Request {
/// Accept the session as a publisher, using the provided broadcast to serve subscriptions.
pub async fn publisher(mut self, source: broadcast::Subscriber) -> Result<Publisher, SessionError> {
let setup = self.setup(setup::Role::Publisher)?;
setup.encode(&mut self.control.0).await?;
let control = Control::new(self.control.0, self.control.1, setup.extensions);
let publisher = Publisher::new(self.session, control, source);
Ok(publisher)
}
/// Accept the session as a subscriber only.
pub async fn subscriber(mut self, source: broadcast::Publisher) -> Result<Subscriber, SessionError> {
let setup = self.setup(setup::Role::Subscriber)?;
setup.encode(&mut self.control.0).await?;
let control = Control::new(self.control.0, self.control.1, setup.extensions);
let subscriber = Subscriber::new(self.session, control, source);
Ok(subscriber)
}
// TODO Accept the session and perform both roles.
/*
pub async fn accept(self) -> anyhow::Result<(Publisher, Subscriber)> {
self.ok(setup::Role::Both).await
}
*/
fn setup(&mut self, role: setup::Role) -> Result<setup::Server, SessionError> {
let server = setup::Server {
role,
version: setup::Version::DRAFT_01,
extensions: self.client.extensions.clone(),
params: Default::default(),
};
log::debug!("sending server SETUP: {:?}", server);
// We need to sure we support the opposite of the client's role.
// ex. if the client is a publisher, we must be a subscriber ONLY.
if !self.client.role.is_compatible(server.role) {
return Err(SessionError::RoleIncompatible(self.client.role, server.role));
}
Ok(server)
}
/// Reject the request, closing the Webtransport session.
pub fn reject(self, code: u32) {
self.session.close(code, b"")
}
/// The role advertised by the client.
pub fn role(&self) -> setup::Role {
self.client.role
}
}

211
moq-transport/src/session/subscriber.rs Normal file
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use webtransport_quinn::{RecvStream, Session};
use std::{
collections::HashMap,
sync::{atomic, Arc, Mutex},
};
use crate::{
cache::{broadcast, segment, track, CacheError},
coding::DecodeError,
message,
message::Message,
session::{Control, SessionError},
VarInt,
};
/// Receives broadcasts over the network, automatically handling subscriptions and caching.
// TODO Clone specific fields when a task actually needs it.
#[derive(Clone, Debug)]
pub struct Subscriber {
// The webtransport session.
webtransport: Session,
// The list of active subscriptions, each guarded by an mutex.
subscribes: Arc<Mutex<HashMap<VarInt, track::Publisher>>>,
// The sequence number for the next subscription.
next: Arc<atomic::AtomicU32>,
// A channel for sending messages.
control: Control,
// All unknown subscribes comes here.
source: broadcast::Publisher,
}
impl Subscriber {
pub(crate) fn new(webtransport: Session, control: Control, source: broadcast::Publisher) -> Self {
Self {
webtransport,
subscribes: Default::default(),
next: Default::default(),
control,
source,
}
}
pub async fn run(self) -> Result<(), SessionError> {
let inbound = self.clone().run_inbound();
let streams = self.clone().run_streams();
let source = self.clone().run_source();
// Return the first error.
tokio::select! {
res = inbound => res,
res = streams => res,
res = source => res,
}
}
async fn run_inbound(mut self) -> Result<(), SessionError> {
loop {
let msg = self.control.recv().await?;
log::info!("message received: {:?}", msg);
if let Err(err) = self.recv_message(&msg) {
log::warn!("message error: {:?} {:?}", err, msg);
}
}
}
fn recv_message(&mut self, msg: &Message) -> Result<(), SessionError> {
match msg {
Message::Announce(_) => Ok(()), // don't care
Message::Unannounce(_) => Ok(()), // also don't care
Message::SubscribeOk(_msg) => Ok(()), // don't care
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())),
}
}
fn recv_subscribe_error(&mut self, id: VarInt, err: CacheError) -> Result<(), SessionError> {
let mut subscribes = self.subscribes.lock().unwrap();
let subscribe = subscribes.remove(&id).ok_or(CacheError::NotFound)?;
subscribe.close(err)?;
Ok(())
}
async fn run_streams(self) -> Result<(), SessionError> {
loop {
// Accept all incoming unidirectional streams.
let stream = self.webtransport.accept_uni().await?;
let this = self.clone();
tokio::spawn(async move {
if let Err(err) = this.run_stream(stream).await {
log::warn!("failed to receive stream: err={:#?}", err);
}
});
}
}
async fn run_stream(self, mut stream: RecvStream) -> Result<(), SessionError> {
// Decode the object on the data stream.
let mut object = message::Object::decode(&mut stream, &self.control.ext)
.await
.map_err(|e| SessionError::Unknown(e.to_string()))?;
log::trace!("first object: {:?}", object);
// A new scope is needed because the async compiler is dumb
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.group,
priority: object.priority,
expires: object.expires,
})?
};
log::trace!("received segment: {:?}", segment);
// Create the first fragment
let mut fragment = segment.push_fragment(object.sequence, object.size.map(usize::from))?;
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, &self.control.ext).await {
Ok(next) => next,
// No more objects
Err(DecodeError::Final) => break,
// Unknown error
Err(err) => return Err(err.into()),
};
log::trace!("next object: {:?}", object);
// 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);
}
object = next;
// Create a new object.
fragment = segment.push_fragment(object.sequence, object.size.map(usize::from))?;
remain = object.size.map(usize::from);
log::trace!("next fragment: {:?}", fragment);
}
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.
Some(data) => {
remain = remain.map(|r| r - data.bytes.len());
log::trace!("next chunk: {:?}", data);
fragment.chunk(data.bytes)?;
}
}
}
Ok(())
}
async fn run_source(mut self) -> Result<(), SessionError> {
loop {
// NOTE: This returns Closed when the source is closed.
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));
self.subscribes.lock().unwrap().insert(id, track);
let msg = message::Subscribe {
id,
namespace: self.control.ext.subscribe_split.then(|| "".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?;
}
}
}

72
moq-transport/src/setup/client.rs Normal file
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use super::{Extensions, Role, Versions};
use crate::{
coding::{Decode, DecodeError, Encode, EncodeError, Params},
VarInt,
};
use crate::coding::{AsyncRead, AsyncWrite};
/// Sent by the client to setup the session.
// NOTE: This is not a message type, but rather the control stream header.
// Proposal: https://github.com/moq-wg/moq-transport/issues/138
#[derive(Debug)]
pub struct Client {
/// The list of supported versions in preferred order.
pub versions: Versions,
/// Indicate if the client is a publisher, a subscriber, or both.
pub role: Role,
/// A list of known/offered extensions.
pub extensions: Extensions,
/// 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() != 0x40 {
return Err(DecodeError::InvalidMessage(typ));
}
let versions = Versions::decode(r).await?;
let mut params = Params::decode(r).await?;
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);
}
let extensions = Extensions::load(&mut params).await?;
Ok(Self {
versions,
role,
extensions,
params,
})
}
/// Encode a server setup message.
pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
VarInt::from_u32(0x40).encode(w).await?;
self.versions.encode(w).await?;
let mut params = self.params.clone();
params.set(VarInt::from_u32(0), self.role).await?;
self.extensions.store(&mut params).await?;
params.encode(w).await?;
Ok(())
}
}

84
moq-transport/src/setup/extension.rs Normal file
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use tokio::io::{AsyncRead, AsyncWrite};
use crate::coding::{Decode, DecodeError, Encode, EncodeError, Params};
use crate::session::SessionError;
use crate::VarInt;
use paste::paste;
/// This is a custom extension scheme to allow/require draft PRs.
///
/// By convention, the extension number is the PR number + 0xe0000.
macro_rules! extensions {
{$($name:ident = $val:expr,)*} => {
#[derive(Clone, Default, Debug)]
pub struct Extensions {
$(
pub $name: bool,
)*
}
impl Extensions {
pub async fn load(params: &mut Params) -> Result<Self, DecodeError> {
let mut extensions = Self::default();
$(
if let Some(_) = params.get::<ExtensionExists>(VarInt::from_u32($val)).await? {
extensions.$name = true
}
)*
Ok(extensions)
}
pub async fn store(&self, params: &mut Params) -> Result<(), EncodeError> {
$(
if self.$name {
params.set(VarInt::from_u32($val), ExtensionExists{}).await?;
}
)*
Ok(())
}
paste! {
$(
pub fn [<require_ $name>](&self) -> Result<(), SessionError> {
match self.$name {
true => Ok(()),
false => Err(SessionError::RequiredExtension(VarInt::from_u32($val))),
}
}
)*
}
}
}
}
struct ExtensionExists;
#[async_trait::async_trait]
impl Decode for ExtensionExists {
async fn decode<R: AsyncRead>(_r: &mut R) -> Result<Self, DecodeError> {
Ok(ExtensionExists {})
}
}
#[async_trait::async_trait]
impl Encode for ExtensionExists {
async fn encode<W: AsyncWrite>(&self, _w: &mut W) -> Result<(), EncodeError> {
Ok(())
}
}
extensions! {
// required for publishers: OBJECT contains expires VarInt in seconds: https://github.com/moq-wg/moq-transport/issues/249
// TODO write up a PR
object_expires = 0xe00f9,
// required: SUBSCRIBE chooses track ID: https://github.com/moq-wg/moq-transport/pull/258
subscriber_id = 0xe0102,
// optional: SUBSCRIBE contains namespace/name tuple: https://github.com/moq-wg/moq-transport/pull/277
subscribe_split = 0xe0115,
}

17
moq-transport/src/setup/mod.rs Normal file
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//! Messages used for the MoQ Transport handshake.
//!
//! After establishing the WebTransport session, the client creates a bidirectional QUIC stream.
//! The client sends the [Client] message and the server responds with the [Server] message.
//! Both sides negotate the [Version] and [Role].
mod client;
mod extension;
mod role;
mod server;
mod version;
pub use client::*;
pub use extension::*;
pub use role::*;
pub use server::*;
pub use version::*;

74
moq-transport/src/setup/role.rs Normal file
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use crate::coding::{AsyncRead, AsyncWrite};
use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
/// Indicates the endpoint is a publisher, subscriber, or both.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Role {
Publisher,
Subscriber,
Both,
}
impl Role {
/// Returns true if the role is publisher.
pub fn is_publisher(&self) -> bool {
match self {
Self::Publisher | Self::Both => true,
Self::Subscriber => false,
}
}
/// Returns true if the role is a subscriber.
pub fn is_subscriber(&self) -> bool {
match self {
Self::Subscriber | Self::Both => true,
Self::Publisher => false,
}
}
/// Returns true if two endpoints are compatible.
pub fn is_compatible(&self, other: Role) -> bool {
self.is_publisher() == other.is_subscriber() && self.is_subscriber() == other.is_publisher()
}
}
impl From<Role> for VarInt {
fn from(r: Role) -> Self {
VarInt::from_u32(match r {
Role::Publisher => 0x1,
Role::Subscriber => 0x2,
Role::Both => 0x3,
})
}
}
impl TryFrom<VarInt> for Role {
type Error = DecodeError;
fn try_from(v: VarInt) -> Result<Self, Self::Error> {
match v.into_inner() {
0x1 => Ok(Self::Publisher),
0x2 => Ok(Self::Subscriber),
0x3 => Ok(Self::Both),
_ => Err(DecodeError::InvalidRole(v)),
}
}
}
#[async_trait::async_trait]
impl Decode for Role {
/// Decode the role.
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.
async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
VarInt::from(*self).encode(w).await
}
}

71
moq-transport/src/setup/server.rs Normal file
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use super::{Extensions, Role, Version};
use crate::{
coding::{Decode, DecodeError, Encode, EncodeError, Params},
VarInt,
};
use crate::coding::{AsyncRead, AsyncWrite};
/// Sent by the server in response to a client setup.
// NOTE: This is not a message type, but rather the control stream header.
// Proposal: https://github.com/moq-wg/moq-transport/issues/138
#[derive(Debug)]
pub struct Server {
/// The list of supported versions in preferred order.
pub version: Version,
/// Indicate if the server is a publisher, a subscriber, or both.
// Proposal: moq-wg/moq-transport#151
pub role: Role,
/// Custom extensions.
pub extensions: Extensions,
/// 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() != 0x41 {
return Err(DecodeError::InvalidMessage(typ));
}
let version = Version::decode(r).await?;
let mut params = Params::decode(r).await?;
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);
}
let extensions = Extensions::load(&mut params).await?;
Ok(Self {
version,
role,
extensions,
params,
})
}
/// Encode the server setup.
pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
VarInt::from_u32(0x41).encode(w).await?;
self.version.encode(w).await?;
let mut params = self.params.clone();
params.set(VarInt::from_u32(0), self.role).await?;
self.extensions.store(&mut params).await?;
params.encode(w).await?;
Ok(())
}
}

155
moq-transport/src/setup/version.rs Normal file
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use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
use crate::coding::{AsyncRead, AsyncWrite};
use std::ops::Deref;
/// A version number negotiated during the setup.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Version(pub VarInt);
impl Version {
/// https://www.ietf.org/archive/id/draft-ietf-moq-transport-00.html
pub const DRAFT_00: Version = Version(VarInt::from_u32(0xff000000));
/// https://www.ietf.org/archive/id/draft-ietf-moq-transport-01.html
pub const DRAFT_01: Version = Version(VarInt::from_u32(0xff000001));
/// Fork of draft-ietf-moq-transport-00.
///
/// Rough list of differences:
///
/// # Messages
/// - Messages are sent over a control stream or a data stream.
/// - Data streams: each unidirectional stream contains a single OBJECT message.
/// - Control stream: a (client-initiated) bidirectional stream containing SETUP and then all other messages.
/// - Messages do not contain a length; unknown messages are fatal.
///
/// # SETUP
/// - SETUP is split into SETUP_CLIENT and SETUP_SERVER with separate IDs.
/// - SETUP uses version `0xff00` for draft-00.
/// - SETUP no longer contains optional parameters; all are encoded in order and possibly zero.
/// - SETUP `role` indicates the role of the sender, not the role of the server.
/// - SETUP `path` field removed; use WebTransport for path.
///
/// # SUBSCRIBE
/// - SUBSCRIBE `full_name` is split into separate `namespace` and `name` fields.
/// - SUBSCRIBE no longer contains optional parameters; all are encoded in order and possibly zero.
/// - SUBSCRIBE no longer contains the `auth` parameter; use WebTransport for auth.
/// - SUBSCRIBE no longer contains the `group` parameter; concept no longer exists.
/// - SUBSCRIBE contains the `id` instead of SUBSCRIBE_OK.
/// - SUBSCRIBE_OK and SUBSCRIBE_ERROR reference the subscription `id` the instead of the track `full_name`.
/// - SUBSCRIBE_ERROR was renamed to SUBSCRIBE_RESET, sent by publisher to terminate a SUBSCRIBE.
/// - SUBSCRIBE_STOP was added, sent by the subscriber to terminate a SUBSCRIBE.
/// - SUBSCRIBE_OK no longer has `expires`.
///
/// # ANNOUNCE
/// - ANNOUNCE no longer contains optional parameters; all are encoded in order and possibly zero.
/// - ANNOUNCE no longer contains the `auth` field; use WebTransport for auth.
/// - ANNOUNCE_ERROR was renamed to ANNOUNCE_RESET, sent by publisher to terminate an ANNOUNCE.
/// - ANNOUNCE_STOP was added, sent by the subscriber to terminate an ANNOUNCE.
///
/// # OBJECT
/// - OBJECT uses a dedicated QUIC stream.
/// - OBJECT has no size and continues until stream FIN.
/// - OBJECT `priority` is a i32 instead of a varint. (for practical reasons)
/// - OBJECT `expires` was added, a varint in seconds.
/// - OBJECT `group` was removed.
///
/// # 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.
/// This was only used for a short time until extensions were created.
///
/// - 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 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 {
fn from(v: VarInt) -> Self {
Self(v)
}
}
impl From<Version> for VarInt {
fn from(v: Version) -> Self {
v.0
}
}
impl Version {
/// Decode the version number.
pub async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
let v = VarInt::decode(r).await?;
Ok(Self(v))
}
/// Encode the version number.
pub async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
self.0.encode(w).await?;
Ok(())
}
}
/// A list of versions in arbitrary order.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Versions(Vec<Version>);
#[async_trait::async_trait]
impl Decode for Versions {
/// Decode the version list.
async fn decode<R: AsyncRead>(r: &mut R) -> Result<Self, DecodeError> {
let count = VarInt::decode(r).await?.into_inner();
let mut vs = Vec::new();
for _ in 0..count {
let v = Version::decode(r).await?;
vs.push(v);
}
Ok(Self(vs))
}
}
#[async_trait::async_trait]
impl Encode for Versions {
/// Encode the version list.
async fn encode<W: AsyncWrite>(&self, w: &mut W) -> Result<(), EncodeError> {
let size: VarInt = self.0.len().try_into()?;
size.encode(w).await?;
for v in &self.0 {
v.encode(w).await?;
}
Ok(())
}
}
impl Deref for Versions {
type Target = Vec<Version>;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl From<Vec<Version>> for Versions {
fn from(vs: Vec<Version>) -> Self {
Self(vs)
}
}
impl<const N: usize> From<[Version; N]> for Versions {
fn from(vs: [Version; N]) -> Self {
Self(vs.to_vec())
}
}