Add optional/required extensions. (#117)

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

.dockerignore

@@ -0,0 +1,3 @@
+target
+dev
+*.mp4

.editorconfig

@@ -8,3 +8,10 @@ insert_final_newline = true
 indent_style = tab
 indent_size = 4
 max_line_length = 120
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.yml]
+indent_style = space
+indent_size = 2

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.github/workflows/check.yml

@@ -1,29 +0,0 @@
-name: moq.rs
-
-on:
-  pull_request:
-    branches: [ "main" ]
-
-env:
-  CARGO_TERM_COLOR: always
-
-jobs:
-  check:
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v3
-
-    - name: toolchain
-      uses: actions-rust-lang/setup-rust-toolchain@v1
-      with:
-        components: clippy, rustfmt
-
-    - name: test
-      run: cargo test --verbose
-
-    - name: clippy
-      run: cargo clippy
-
-    - name: fmt
-      run: cargo fmt --check

.github/workflows/main.yml

@@ -0,0 +1,65 @@
+name: main
+
+on:
+  push:
+    branches: ["main"]
+
+env:
+  REGISTRY: docker.io
+  IMAGE: kixelated/moq-rs
+  IMAGE-PUB: kixelated/moq-pub
+  SERVICE: api # Restart the API service TODO and relays
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+      id-token: write
+
+    # Only one release at a time and cancel prior releases
+    concurrency:
+      group: release
+      cancel-in-progress: true
+
+    steps:
+      - uses: actions/checkout@v3
+
+      # I'm paying for Depot for faster ARM builds.
+      - uses: depot/setup-action@v1
+
+      - uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      # Build and push Docker image with Depot
+      - uses: depot/build-push-action@v1
+        with:
+          project: r257ctfqm6
+          context: .
+          push: true
+          tags: ${{env.REGISTRY}}/${{env.IMAGE}}
+          platforms: linux/amd64,linux/arm64
+
+      # Same, but include ffmpeg for publishing BBB
+      - uses: depot/build-push-action@v1
+        with:
+          project: r257ctfqm6
+          context: .
+          push: true
+          target: moq-pub # instead of the default target
+          tags: ${{env.REGISTRY}}/${{env.IMAGE-PUB}}
+          platforms: linux/amd64,linux/arm64
+
+      # Log in to GCP
+      - uses: google-github-actions/auth@v1
+        with:
+          credentials_json: ${{ secrets.GCP_SERVICE_ACCOUNT_KEY }}
+
+      # Deploy to cloud run
+      - uses: google-github-actions/deploy-cloudrun@v1
+        with:
+          service: ${{env.SERVICE}}
+          image: ${{env.REGISTRY}}/${{env.IMAGE}}

.github/workflows/pr.yml

@@ -0,0 +1,28 @@
+name: pr
+
+on:
+  pull_request:
+    branches: ["main"]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+
+      # Install Rust with clippy/rustfmt
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          components: clippy, rustfmt
+
+      # Make sure u guys don't write bad code
+      - run: cargo test --verbose
+      - run: cargo clippy --no-deps
+      - run: cargo fmt --check
+
+      # Check for unused dependencies
+      - uses: bnjbvr/cargo-machete@main

.gitignore

@@ -1,3 +1,4 @@
 .DS_Store
 target/
 logs/
+*.mp4

Cargo.toml

@@ -1,7 +1,3 @@
 [workspace]
-members = [
-    "moq-transport",
-	"moq-transport-quinn",
-    "moq-demo",
-    "moq-warp",
-]
+members = ["moq-transport", "moq-relay", "moq-pub", "moq-api"]
+resolver = "2"

Dockerfile

@@ -0,0 +1,39 @@
+FROM rust:latest as builder
+
+# Create a build directory and copy over all of the files
+WORKDIR /build
+COPY . .
+
+# Reuse a cache between builds.
+# I tried to `cargo install`, but it doesn't seem to work with workspaces.
+# There's also issues with the cache mount since it builds into /usr/local/cargo/bin, and we can't mount that without clobbering cargo itself.
+# We instead we build the binaries and copy them to the cargo bin directory.
+RUN --mount=type=cache,target=/usr/local/cargo/registry \
+    --mount=type=cache,target=/build/target \
+    cargo build --release && cp /build/target/release/moq-* /usr/local/cargo/bin
+
+# Special image for moq-pub with ffmpeg and a publish script included.
+FROM rust:latest as moq-pub
+
+# Install required utilities and ffmpeg
+RUN apt-get update && \
+    apt-get install -y ffmpeg wget
+
+# Copy the publish script into the image
+COPY deploy/publish.sh /usr/local/bin/publish
+
+# Copy the compiled binary
+COPY --from=builder /usr/local/cargo/bin/moq-pub /usr/local/cargo/bin/moq-pub
+CMD [ "publish" ]
+
+# moq-rs image with just the binaries
+FROM rust:latest as moq-rs
+
+LABEL org.opencontainers.image.source=https://github.com/kixelated/moq-rs
+LABEL org.opencontainers.image.licenses="MIT OR Apache-2.0"
+
+# Fly.io entrypoint
+ADD deploy/fly-relay.sh .
+
+# Copy the compiled binaries
+COPY --from=builder /usr/local/cargo/bin /usr/local/cargo/bin

HACKATHON.md

@@ -0,0 +1,53 @@
+# Hackathon
+
+IETF Prague 118
+
+## MoqTransport
+
+Reference libraries are available at [moq-rs](https://github.com/kixelated/moq-rs) and [moq-js](https://github.com/kixelated/moq-js). The Rust library is [well documented](https://docs.rs/moq-transport/latest/moq_transport/) but the web library, not so much.
+
+**TODO** Update both to draft-01.
+**TODO** Switch any remaining forks over to extensions. ex: track_id in SUBSCRIBE
+
+The stream mapping right now is quite rigid: `stream == group == object`.
+
+**TODO** Support multiple objects per group. They MUST NOT use different priorities, different tracks, or out-of-order sequences.
+
+The API and cache aren't designed to send/receive arbitrary objects over arbitrary streams as specified in the draft. I don't think it should, and it wouldn't be possible to implement in time for the hackathon anyway.
+
+**TODO** Make an extension to enforce this stream mapping?
+
+## Generic Relay
+
+I'm hosting a simple CDN at: `relay.quic.video`
+
+The traffic is sharded based on the WebTransport path to avoid namespace collisions. Think of it like a customer ID, although it's completely unauthenticated for now. Use your username or whatever string you want: `CONNECT https://relay.quic.video/alan`.
+
+**TODO** Currently, it performs an implicit `ANNOUNCE ""` when `role=publisher`. This means there can only be a single publisher per shard and `role=both` is not supported. I should have explicit `ANNOUNCE` messages supported before the hackathon to remove this limitation.
+
+**TODO** I don't know if I will have subscribe hints fully working in time. They will be parsed but might be ignored.
+
+## CMAF Media
+
+You can [publish](https://quic.video/publish) and [watch](https://quic.video/watch) broadcasts.
+There's a [24/7 bunny stream](https://quic.video/watch/bbb) or you can publish your own using [moq-pub](https://github.com/kixelated/moq-rs/tree/main/moq-pub).
+
+If you want to fetch from the relay directly, the name of the broadcast is the path. For example, `https://quic.video/watch/bbb` can be accessed at `relay.quic.video/bbb`. 
+
+The namespace is empty and the catalog track is `.catalog`. I'm currently using simple JSON catalog with no support for delta updates.
+
+**TODO** update to the proposed [Warp catalog](https://datatracker.ietf.org/doc/draft-wilaw-moq-catalogformat/).
+
+The media tracks uses a single (unbounded) object per group. Video groups are per GoP, while audio groups are per frame. There's also an init track containing information required to initialize the decoder.
+
+**TODO** Base64 encode the init track in the catalog.
+
+
+## Clock
+
+**TODO** Host a clock demo that sends a group per second:
+
+```
+GROUP: YYYY-MM-DD HH:MM
+OBJECT: SS
+```

README.md

@@ -1,40 +1,64 @@
-# Media over QUIC
+<p align="center">
+	<img height="128px" src="https://github.com/kixelated/moq-rs/blob/main/.github/logo.svg" alt="Media over QUIC">
+</p>
 
 Media over QUIC (MoQ) is a live media delivery protocol utilizing QUIC streams.
-See the [Warp draft](https://datatracker.ietf.org/doc/draft-lcurley-warp/).
+See [quic.video](https://quic.video) for more information.
 
-This repository is a Rust server that supports both contribution (ingest) and distribution (playback).
-It requires a client, such as [moq-js](https://github.com/kixelated/moq-js).
+This repository contains a few crates:
 
-## Setup
+-   **moq-relay**: A relay server, accepting content from publishers and fanning it out to subscribers.
+-   **moq-pub**: A publish client, accepting media from stdin (ex. via ffmpeg) and sending it to a remote server.
+-   **moq-transport**: An async implementation of the underlying MoQ protocol.
+-   **moq-api**: A HTTP API server that stores the origin for each broadcast, backed by redis.
 
-### Certificates
+There's currently no way to view media with this repo; you'll need to use [moq-js](https://github.com/kixelated/moq-js) for that.
 
-Unfortunately, QUIC mandates TLS and makes local development difficult.
-If you have a valid certificate you can use it instead of self-signing.
+## Development
 
-Use [mkcert](https://github.com/FiloSottile/mkcert) to generate a self-signed certificate.
-Unfortunately, this currently requires Go in order to [fork](https://github.com/FiloSottile/mkcert/pull/513) the tool.
-
-```
-./cert/generate
-```
-
-Unfortunately, WebTransport in Chrome currently (May 2023) doesn't verify certificates using the root CA.
-The workaround is to use the `serverFingerprints` options, which requires the certificate MUST be only valid for at most **14 days**.
-This is also why we're using a fork of mkcert, because it generates certificates valid for years by default.
-This limitation will be removed once Chrome uses the system CA for WebTransport.
+Use the [dev helper scripts](dev/README.md) for local development.
 
 ## Usage
 
-Run the server:
+### moq-relay
 
-```
-cargo run
-```
+**moq-relay** is a server that forwards subscriptions from publishers to subscribers, caching and deduplicating along the way.
+It's designed to be run in a datacenter, relaying media across multiple hops to deduplicate and improve QoS.
+The relays register themselves via the [moq-api](moq-api) endpoints, which is used to discover other relays and share broadcasts.
 
-This listens for WebTransport connections on `https://localhost:4443` by default.
-Use a [MoQ client](https://github.com/kixelated/moq-js) to connect to the server.
+Notable arguments:
+
+-   `--listen <ADDR>` Listen on this address, default: `[::]:4443`
+-   `--tls-cert <CERT>` Use the certificate file at this path
+-   `--tls-key <KEY>` Use the private key at this path
+-   `--dev` Listen via HTTPS as well, serving the `/fingerprint` of the self-signed certificate. (dev only)
+
+This listens for WebTransport connections on `UDP https://localhost:4443` by default.
+You need a client to connect to that address, to both publish and consume media.
+
+### moq-pub
+
+This is a client that publishes a fMP4 stream from stdin over MoQ.
+This can be combined with ffmpeg (and other tools) to produce a live stream.
+
+Notable arguments:
+
+-   `<URL>` connect to the given address, which must start with `https://` for WebTransport.
+
+**NOTE**: We're very particular about the fMP4 ingested. See [this script](dev/pub) for the required ffmpeg flags.
+
+### moq-transport
+
+A media-agnostic library used by [moq-relay](moq-relay) and [moq-pub](moq-pub) to serve the underlying subscriptions.
+It has caching/deduplication built-in, so your application is oblivious to the number of connections under the hood.
+
+See the published [crate](https://crates.io/crates/moq-transport) and [documentation](https://docs.rs/moq-transport/latest/moq_transport/).
+
+### moq-api
+
+This is a API server that exposes a REST API.
+It's used by relays to inserts themselves as origins when publishing, and to find the origin when subscribing.
+It's basically just a thin wrapper around redis that is only needed to run multiple relays in a (simple) cluster.
 
 ## License
 

deploy/fly-relay.sh

@@ -0,0 +1,8 @@
+#!/usr/bin/env sh
+
+mkdir cert
+# Nothing to see here...
+echo "$MOQ_CRT" | base64 -d > dev/moq-demo.crt
+echo "$MOQ_KEY" | base64 -d > dev/moq-demo.key
+
+RUST_LOG=info /usr/local/cargo/bin/moq-relay --tls-cert dev/moq-demo.crt --tls-key dev/moq-demo.key

deploy/fly.toml

@@ -0,0 +1,20 @@
+app = "englishm-moq-relay"
+kill_signal = "SIGINT"
+kill_timeout = 5
+
+[env]
+PORT = "4443"
+
+[experimental]
+cmd = "./fly-relay.sh"
+
+[[services]]
+internal_port = 4443
+protocol = "udp"
+
+[services.concurrency]
+hard_limit = 25
+soft_limit = 20
+
+[[services.ports]]
+port = "4443"

deploy/publish.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+set -euo pipefail
+
+ADDR=${ADDR:-"https://relay.quic.video"}
+NAME=${NAME:-"bbb"}
+URL=${URL:-"http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4"}
+
+# Download the funny bunny
+wget -nv "${URL}" -O "${NAME}.mp4"
+
+# ffmpeg
+#   -hide_banner: Hide the banner
+#   -v quiet: and any other output
+#   -stats: But we still want some stats on stderr
+#   -stream_loop -1: Loop the broadcast an infinite number of times
+#   -re: Output in real-time
+#   -i "${INPUT}": Read from a file on disk
+#   -vf "drawtext": Render the current time in the corner of the video
+#   -an: Disable audio for now
+#   -b:v 3M: Output video at 3Mbps
+#   -preset ultrafast: Don't use much CPU at the cost of quality
+#   -tune zerolatency: Optimize for latency at the cost of quality
+#   -f mp4: Output to mp4 format
+#   -movflags: Build a fMP4 file with a frame per fragment
+# - | moq-pub: Output to stdout and moq-pub to publish
+
+# Run ffmpeg
+ffmpeg \
+	-stream_loop -1 \
+	-hide_banner \
+	-v quiet \
+	-re \
+    -i "${NAME}.mp4" \
+	-vf "drawtext=fontfile=/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf:text='%{gmtime\: %H\\\\\:%M\\\\\:%S.%3N}':x=(W-tw)-24:y=24:fontsize=48:fontcolor=white:box=1:boxcolor=black@0.5" \
+	-an \
+	-b:v 3M \
+	-preset ultrafast \
+	-tune zerolatency \
+    -f mp4 \
+	-movflags empty_moov+frag_every_frame+separate_moof+omit_tfhd_offset \
+	- | moq-pub "${ADDR}/${NAME}"

dev/.gitignore

@@ -1,3 +1,4 @@
 *.crt
 *.key
 *.hex
+*.mp4

dev/README.md

@@ -0,0 +1,118 @@
+# Local Development
+
+This is a collection of helpful scripts for local development.
+
+## Setup
+
+### moq-relay
+
+Unfortunately, QUIC mandates TLS and makes local development difficult.
+If you have a valid certificate you can use it instead of self-signing.
+
+Use [mkcert](https://github.com/FiloSottile/mkcert) to generate a self-signed certificate.
+Unfortunately, this currently requires [Go](https://golang.org/) to be installed in order to [fork](https://github.com/FiloSottile/mkcert/pull/513) the tool.
+Somebody should get that merged or make something similar in Rust...
+
+```bash
+./dev/cert
+```
+
+Unfortunately, WebTransport in Chrome currently (May 2023) doesn't verify certificates using the root CA.
+The workaround is to use the `serverFingerprints` options, which requires the certificate MUST be only valid for at most **14 days**.
+This is also why we're using a fork of mkcert, because it generates certificates valid for years by default.
+This limitation will be removed once Chrome uses the system CA for WebTransport.
+
+### moq-pub
+
+You'll want some test footage to broadcast.
+Anything works, but make sure the codec is supported by the player since `moq-pub` does not re-encode.
+
+Here's a criticially acclaimed short film:
+
+```bash
+mkdir media
+wget http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4 -O dev/source.mp4
+```
+
+`moq-pub` uses [ffmpeg](https://ffmpeg.org/) to convert the media to fMP4.
+You should have it installed already if you're a video nerd, otherwise:
+
+```bash
+brew install ffmpeg
+```
+
+### moq-api
+
+`moq-api` uses a redis instance to store active origins for clustering.
+This is not relevant for most local development and the code path is skipped by default.
+
+However, if you want to test the clustering, you'll need either either [Docker](https://www.docker.com/) or [Podman](https://podman.io/) installed.
+We run the redis instance via a container automatically as part of `dev/api`.
+
+## Development
+
+**tl;dr** run these commands in seperate terminals:
+
+```bash
+./dev/cert
+./dev/relay
+./dev/pub
+```
+
+They will each print out a URL you can use to publish/watch broadcasts.
+
+### moq-relay
+
+You can run the relay with the following command, automatically using the self-signed certificates generated earlier.
+This listens for WebTransport connections on WebTransport `https://localhost:4443` by default.
+
+```bash
+./dev/relay
+```
+
+It will print out a URL when you can use to publish. Alternatively, you can use `dev/pub` instead.
+
+> Publish URL: https://quic.video/publish/?server=localhost:4443
+
+### moq-pub
+
+The following command runs a development instance, broadcasing `dev/source.mp4` to WebTransport `https://localhost:4443`:
+
+```bash
+./dev/pub
+```
+
+It will print out a URL when you can use to watch.
+By default, the broadcast name is `dev` but you can overwrite it with the `NAME` env.
+
+> Watch URL: https://quic.video/watch/dev?server=localhost:4443
+
+If you're debugging encoding issues, you can use this script to dump the file to disk instead, defaulting to
+`dev/output.mp4`.
+
+```bash
+./dev/pub-file
+```
+
+### moq-api
+
+The following commands runs an API server, listening for HTTP requests on `http://localhost:4442` by default.
+
+```bash
+./dev/api
+```
+
+Nodes can now register themselves via the API, which means you can run multiple interconnected relays.
+There's two separate `dev/relay-0` and `dev/relay-1` scripts to test clustering locally:
+
+```bash
+./dev/relay-0
+./dev/relay-1
+```
+
+These listen on `:4443` and `:4444` respectively, inserting themselves into the origin database as `localhost:$PORT`.
+
+There's also a separate `dev/pub-1` script to publish to the `:4444` instance.
+You can use the exisitng `dev/pub` script to publish to the `:4443` instance.
+
+If all goes well, you would be able to publish to one relay and watch from the other.

dev/api

@@ -0,0 +1,45 @@
+#!/bin/bash
+set -euo pipefail
+
+# Change directory to the root of the project
+cd "$(dirname "$0")/.."
+
+# Use debug logging by default
+export RUST_LOG="${RUST_LOG:-debug}"
+
+# Run the API server on port 4442 by default
+HOST="${HOST:-[::]}"
+PORT="${PORT:-4442}"
+LISTEN="${LISTEN:-$HOST:$PORT}"
+
+# Check for Podman/Docker and set runtime accordingly
+if command -v podman &> /dev/null; then
+    RUNTIME=podman
+elif command -v docker &> /dev/null; then
+    RUNTIME=docker
+else
+    echo "Neither podman or docker found in PATH. Exiting."
+    exit 1
+fi
+
+REDIS_PORT=${REDIS_PORT:-6400} # The default is 6379, but we'll use 6400 to avoid conflicts
+
+# Cleanup function to stop Redis when script exits
+cleanup() {
+    $RUNTIME rm -f moq-redis || true
+}
+
+# Stop the redis instance if it's still running
+cleanup
+
+# Run a Redis instance
+REDIS_CONTAINER=$($RUNTIME run --rm --name moq-redis -d -p "$REDIS_PORT:6379" redis:latest)
+
+# Cleanup function to stop Redis when script exits
+trap cleanup EXIT
+
+# Default to a sqlite database in memory
+DATABASE="${DATABASE-sqlite::memory:}"
+
+# Run the relay and forward any arguments
+cargo run --bin moq-api -- --listen "$LISTEN" --redis "redis://localhost:$REDIS_PORT" "$@"

dev/pub

@@ -0,0 +1,40 @@
+#!/bin/bash
+set -euo pipefail
+
+# Change directory to the root of the project
+cd "$(dirname "$0")/.."
+
+# Use debug logging by default
+export RUST_LOG="${RUST_LOG:-debug}"
+
+# Connect to localhost by default.
+HOST="${HOST:-localhost}"
+PORT="${PORT:-4443}"
+ADDR="${ADDR:-$HOST:$PORT}"
+
+# Generate a random 16 character name by default.
+#NAME="${NAME:-$(head /dev/urandom | LC_ALL=C tr -dc 'a-zA-Z0-9' | head -c 16)}"
+
+# JK use the name "dev" instead
+# TODO use that random name if the host is not localhost
+NAME="${NAME:-dev}"
+
+# Combine the host and name into a URL.
+URL="${URL:-"https://$ADDR/$NAME"}"
+
+# Default to a source video
+INPUT="${INPUT:-dev/source.mp4}"
+
+# Print out the watch URL
+echo "Watch URL: https://quic.video/watch/$NAME?server=$ADDR"
+
+# Run ffmpeg and pipe the output to moq-pub
+# TODO enable audio again once fixed.
+ffmpeg -hide_banner -v quiet \
+	-stream_loop -1 -re \
+	-i "$INPUT" \
+	-c copy \
+	-an \
+	-f mp4 -movflags cmaf+separate_moof+delay_moov+skip_trailer \
+	-frag_duration 1 \
+	- | cargo run --bin moq-pub -- "$URL" "$@"

dev/pub-1

@@ -0,0 +1,10 @@
+#!/bin/bash
+set -euo pipefail
+
+# Change directory to the root of the project
+cd "$(dirname "$0")/.."
+
+# Connect to the 2nd relay by default.
+export PORT="${PORT:-4444}"
+
+./dev/pub

dev/pub-file

@@ -0,0 +1,90 @@
+#!/bin/bash
+set -euo pipefail
+
+# Change directory to the root of the project
+cd "$(dirname "$0")/.."
+
+# Default to a source video
+INPUT="${INPUT:-dev/source.mp4}"
+
+# Output the fragmented MP4 to disk for testing.
+OUTPUT="${OUTPUT:-dev/output.mp4}"
+
+# Run ffmpeg the same as dev/pub, but:
+#   - print any errors/warnings
+#   - only loop twice
+#
+# Note this is artificially slowed down to real-time using the -re flag; you can remove it.
+ffmpeg \
+	-re \
+	-y \
+	-i "$INPUT" \
+	-c copy \
+	-fps_mode passthrough \
+	-f mp4 -movflags cmaf+separate_moof+delay_moov+skip_trailer \
+	-frag_duration 1 \
+	"${OUTPUT}"
+
+# % ffmpeg -f mp4 --ffmpeg -h muxer=mov
+#
+# ffmpeg version 6.0 Copyright (c) 2000-2023 the FFmpeg developers
+# Muxer mov [QuickTime / MOV]:
+#     Common extensions: mov.
+#     Default video codec: h264.
+#     Default audio codec: aac.
+# mov/mp4/tgp/psp/tg2/ipod/ismv/f4v muxer AVOptions:
+#   -movflags          <flags>      E.......... MOV muxer flags (default 0)
+#      rtphint                      E.......... Add RTP hint tracks
+#      empty_moov                   E.......... Make the initial moov atom empty
+#      frag_keyframe                E.......... Fragment at video keyframes
+#      frag_every_frame              E.......... Fragment at every frame
+#      separate_moof                E.......... Write separate moof/mdat atoms for each track
+#      frag_custom                  E.......... Flush fragments on caller requests
+#      isml                         E.......... Create a live smooth streaming feed (for pushing to a publishing point)
+#      faststart                    E.......... Run a second pass to put the index (moov atom) at the beginning of the file
+#      omit_tfhd_offset              E.......... Omit the base data offset in tfhd atoms
+#      disable_chpl                 E.......... Disable Nero chapter atom
+#      default_base_moof              E.......... Set the default-base-is-moof flag in tfhd atoms
+#      dash                         E.......... Write DASH compatible fragmented MP4
+#      cmaf                         E.......... Write CMAF compatible fragmented MP4
+#      frag_discont                 E.......... Signal that the next fragment is discontinuous from earlier ones
+#      delay_moov                   E.......... Delay writing the initial moov until the first fragment is cut, or until the first fragment flush
+#      global_sidx                  E.......... Write a global sidx index at the start of the file
+#      skip_sidx                    E.......... Skip writing of sidx atom
+#      write_colr                   E.......... Write colr atom even if the color info is unspecified (Experimental, may be renamed or changed, do not use from scripts)
+#      prefer_icc                   E.......... If writing colr atom prioritise usage of ICC profile if it exists in stream packet side data
+#      write_gama                   E.......... Write deprecated gama atom
+#      use_metadata_tags              E.......... Use mdta atom for metadata.
+#      skip_trailer                 E.......... Skip writing the mfra/tfra/mfro trailer for fragmented files
+#      negative_cts_offsets              E.......... Use negative CTS offsets (reducing the need for edit lists)
+#   -moov_size         <int>        E.......... maximum moov size so it can be placed at the begin (from 0 to INT_MAX) (default 0)
+#   -rtpflags          <flags>      E.......... RTP muxer flags (default 0)
+#      latm                         E.......... Use MP4A-LATM packetization instead of MPEG4-GENERIC for AAC
+#      rfc2190                      E.......... Use RFC 2190 packetization instead of RFC 4629 for H.263
+#      skip_rtcp                    E.......... Don't send RTCP sender reports
+#      h264_mode0                   E.......... Use mode 0 for H.264 in RTP
+#      send_bye                     E.......... Send RTCP BYE packets when finishing
+#   -skip_iods         <boolean>    E.......... Skip writing iods atom. (default true)
+#   -iods_audio_profile <int>        E.......... iods audio profile atom. (from -1 to 255) (default -1)
+#   -iods_video_profile <int>        E.......... iods video profile atom. (from -1 to 255) (default -1)
+#   -frag_duration     <int>        E.......... Maximum fragment duration (from 0 to INT_MAX) (default 0)
+#   -min_frag_duration <int>        E.......... Minimum fragment duration (from 0 to INT_MAX) (default 0)
+#   -frag_size         <int>        E.......... Maximum fragment size (from 0 to INT_MAX) (default 0)
+#   -ism_lookahead     <int>        E.......... Number of lookahead entries for ISM files (from 0 to 255) (default 0)
+#   -video_track_timescale <int>        E.......... set timescale of all video tracks (from 0 to INT_MAX) (default 0)
+#   -brand             <string>     E.......... Override major brand
+#   -use_editlist      <boolean>    E.......... use edit list (default auto)
+#   -fragment_index    <int>        E.......... Fragment number of the next fragment (from 1 to INT_MAX) (default 1)
+#   -mov_gamma         <float>      E.......... gamma value for gama atom (from 0 to 10) (default 0)
+#   -frag_interleave   <int>        E.......... Interleave samples within fragments (max number of consecutive samples, lower is tighter interleaving, but with more overhead) (from 0 to INT_MAX) (default 0)
+#   -encryption_scheme <string>     E.......... Configures the encryption scheme, allowed values are none, cenc-aes-ctr
+#   -encryption_key    <binary>     E.......... The media encryption key (hex)
+#   -encryption_kid    <binary>     E.......... The media encryption key identifier (hex)
+#   -use_stream_ids_as_track_ids <boolean>    E.......... use stream ids as track ids (default false)
+#   -write_btrt        <boolean>    E.......... force or disable writing btrt (default auto)
+#   -write_tmcd        <boolean>    E.......... force or disable writing tmcd (default auto)
+#   -write_prft        <int>        E.......... Write producer reference time box with specified time source (from 0 to 2) (default 0)
+#      wallclock       1            E..........
+#      pts             2            E..........
+#   -empty_hdlr_name   <boolean>    E.......... write zero-length name string in hdlr atoms within mdia and minf atoms (default false)
+#   -movie_timescale   <int>        E.......... set movie timescale (from 1 to INT_MAX) (default 1000)

dev/relay

@@ -0,0 +1,37 @@
+#!/bin/bash
+set -euo pipefail
+
+# Change directory to the root of the project
+cd "$(dirname "$0")/.."
+
+# Use debug logging by default
+export RUST_LOG="${RUST_LOG:-debug}"
+
+# Default to a self-signed certificate
+# TODO automatically generate if it doesn't exist.
+CERT="${CERT:-dev/localhost.crt}"
+KEY="${KEY:-dev/localhost.key}"
+
+# Default to listening on localhost:4443
+HOST="${HOST:-[::]}"
+PORT="${PORT:-4443}"
+LISTEN="${LISTEN:-$HOST:$PORT}"
+
+# A list of optional args
+ARGS=""
+
+# Connect to the given URL to get origins.
+# TODO default to a public instance?
+if [ -n "${API-}" ]; then
+	ARGS="$ARGS --api $API"
+fi
+
+# Provide our node URL when registering origins.
+if [ -n "${NODE-}" ]; then
+	ARGS="$ARGS --api-node $NODE"
+fi
+
+echo "Publish URL: https://quic.video/publish/?server=localhost:${PORT}"
+
+# Run the relay and forward any arguments
+cargo run --bin moq-relay -- --listen "$LISTEN" --tls-cert "$CERT" --tls-key "$KEY" --dev $ARGS -- "$@"

dev/relay-0

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -euo pipefail
+
+# Change directory to the root of the project
+cd "$(dirname "$0")/.."
+
+# Run an instance that advertises itself to the origin API.
+export PORT="${PORT:-4443}"
+export API="${API:-http://localhost:4442}" # TODO support HTTPS
+export NODE="${NODE:-https://localhost:$PORT}"
+
+./dev/relay

dev/relay-1

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -euo pipefail
+
+# Change directory to the root of the project
+cd "$(dirname "$0")/.."
+
+# Run an instance that advertises itself to the origin API.
+export PORT="${PORT:-4444}"
+export API="${API:-http://localhost:4442}" # TODO support HTTPS
+export NODE="${NODE:-https://localhost:$PORT}"
+
+./dev/relay

dev/setup

@@ -0,0 +1,2 @@
+#!/bin/bash
+set -euo pipefail

moq-api/Cargo.toml

@@ -0,0 +1,43 @@
+[package]
+name = "moq-api"
+description = "Media over QUIC"
+authors = ["Luke Curley"]
+repository = "https://github.com/kixelated/moq-rs"
+license = "MIT OR Apache-2.0"
+
+version = "0.0.1"
+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]
+# HTTP server
+axum = "0.6"
+hyper = { version = "0.14", features = ["full"] }
+tokio = { version = "1", features = ["full"] }
+
+# HTTP client
+reqwest = { version = "0.11", features = ["json", "rustls-tls"] }
+
+# JSON encoding
+serde = "1"
+serde_json = "1"
+
+# CLI
+clap = { version = "4", features = ["derive"] }
+
+# Database
+redis = { version = "0.23", features = [
+	"tokio-rustls-comp",
+	"connection-manager",
+] }
+url = { version = "2", features = ["serde"] }
+
+# Error handling
+log = "0.4"
+env_logger = "0.9"
+thiserror = "1"

moq-api/README.md

@@ -0,0 +1,4 @@
+# moq-api
+
+A thin HTTP API that wraps Redis.
+Basically I didn't want the relays connecting to Redis directly.

moq-api/src/client.rs

@@ -0,0 +1,56 @@
+use url::Url;
+
+use crate::{ApiError, Origin};
+
+#[derive(Clone)]
+pub struct Client {
+	// The address of the moq-api server
+	url: Url,
+
+	client: reqwest::Client,
+}
+
+impl Client {
+	pub fn new(url: Url) -> Self {
+		let client = reqwest::Client::new();
+		Self { url, client }
+	}
+
+	pub async fn get_origin(&self, id: &str) -> Result<Option<Origin>, ApiError> {
+		let url = self.url.join("origin/")?.join(id)?;
+		let resp = self.client.get(url).send().await?;
+		if resp.status() == reqwest::StatusCode::NOT_FOUND {
+			return Ok(None);
+		}
+
+		let origin: Origin = resp.json().await?;
+		Ok(Some(origin))
+	}
+
+	pub async fn set_origin(&mut self, id: &str, origin: &Origin) -> Result<(), ApiError> {
+		let url = self.url.join("origin/")?.join(id)?;
+
+		let resp = self.client.post(url).json(origin).send().await?;
+		resp.error_for_status()?;
+
+		Ok(())
+	}
+
+	pub async fn delete_origin(&mut self, id: &str) -> Result<(), ApiError> {
+		let url = self.url.join("origin/")?.join(id)?;
+
+		let resp = self.client.delete(url).send().await?;
+		resp.error_for_status()?;
+
+		Ok(())
+	}
+
+	pub async fn patch_origin(&mut self, id: &str, origin: &Origin) -> Result<(), ApiError> {
+		let url = self.url.join("origin/")?.join(id)?;
+
+		let resp = self.client.patch(url).json(origin).send().await?;
+		resp.error_for_status()?;
+
+		Ok(())
+	}
+}

moq-api/src/error.rs

@@ -0,0 +1,16 @@
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum ApiError {
+	#[error("redis error: {0}")]
+	Redis(#[from] redis::RedisError),
+
+	#[error("reqwest error: {0}")]
+	Request(#[from] reqwest::Error),
+
+	#[error("hyper error: {0}")]
+	Hyper(#[from] hyper::Error),
+
+	#[error("url error: {0}")]
+	Url(#[from] url::ParseError),
+}

moq-api/src/lib.rs

@@ -0,0 +1,7 @@
+mod client;
+mod error;
+mod model;
+
+pub use client::*;
+pub use error::*;
+pub use model::*;

moq-api/src/main.rs

@@ -0,0 +1,14 @@
+use clap::Parser;
+
+mod server;
+use moq_api::ApiError;
+use server::{Server, ServerConfig};
+
+#[tokio::main]
+async fn main() -> Result<(), ApiError> {
+	env_logger::init();
+
+	let config = ServerConfig::parse();
+	let server = Server::new(config);
+	server.run().await
+}

moq-api/src/model.rs

@@ -0,0 +1,8 @@
+use serde::{Deserialize, Serialize};
+
+use url::Url;
+
+#[derive(Serialize, Deserialize, PartialEq, Eq)]
+pub struct Origin {
+	pub url: Url,
+}

moq-api/src/server.rs

@@ -0,0 +1,171 @@
+use std::net;
+
+use axum::{
+	extract::{Path, State},
+	http::StatusCode,
+	response::{IntoResponse, Response},
+	routing::get,
+	Json, Router,
+};
+
+use clap::Parser;
+
+use redis::{aio::ConnectionManager, AsyncCommands};
+
+use moq_api::{ApiError, Origin};
+
+/// Runs a HTTP API to create/get origins for broadcasts.
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+pub struct ServerConfig {
+	/// Listen for HTTP requests on the given address
+	#[arg(long)]
+	pub listen: net::SocketAddr,
+
+	/// Connect to the given redis instance
+	#[arg(long)]
+	pub redis: url::Url,
+}
+
+pub struct Server {
+	config: ServerConfig,
+}
+
+impl Server {
+	pub fn new(config: ServerConfig) -> Self {
+		Self { config }
+	}
+
+	pub async fn run(self) -> Result<(), ApiError> {
+		log::info!("connecting to redis: url={}", self.config.redis);
+
+		// Create the redis client.
+		let redis = redis::Client::open(self.config.redis)?;
+		let redis = redis
+			.get_tokio_connection_manager() // TODO get_tokio_connection_manager_with_backoff?
+			.await?;
+
+		let app = Router::new()
+			.route(
+				"/origin/:id",
+				get(get_origin)
+					.post(set_origin)
+					.delete(delete_origin)
+					.patch(patch_origin),
+			)
+			.with_state(redis);
+
+		log::info!("serving requests: bind={}", self.config.listen);
+
+		axum::Server::bind(&self.config.listen)
+			.serve(app.into_make_service())
+			.await?;
+
+		Ok(())
+	}
+}
+
+async fn get_origin(
+	Path(id): Path<String>,
+	State(mut redis): State<ConnectionManager>,
+) -> Result<Json<Origin>, AppError> {
+	let key = origin_key(&id);
+
+	let payload: Option<String> = redis.get(&key).await?;
+	let payload = payload.ok_or(AppError::NotFound)?;
+	let origin: Origin = serde_json::from_str(&payload)?;
+
+	Ok(Json(origin))
+}
+
+async fn set_origin(
+	State(mut redis): State<ConnectionManager>,
+	Path(id): Path<String>,
+	Json(origin): Json<Origin>,
+) -> Result<(), AppError> {
+	// TODO validate origin
+
+	let key = origin_key(&id);
+
+	// Convert the input back to JSON after validating it add adding any fields (TODO)
+	let payload = serde_json::to_string(&origin)?;
+
+	let res: Option<String> = redis::cmd("SET")
+		.arg(key)
+		.arg(payload)
+		.arg("NX")
+		.arg("EX")
+		.arg(600) // Set the key to expire in 10 minutes; the origin needs to keep refreshing it.
+		.query_async(&mut redis)
+		.await?;
+
+	if res.is_none() {
+		return Err(AppError::Duplicate);
+	}
+
+	Ok(())
+}
+
+async fn delete_origin(Path(id): Path<String>, State(mut redis): State<ConnectionManager>) -> Result<(), AppError> {
+	let key = origin_key(&id);
+	match redis.del(key).await? {
+		0 => Err(AppError::NotFound),
+		_ => Ok(()),
+	}
+}
+
+// Update the expiration deadline.
+async fn patch_origin(
+	Path(id): Path<String>,
+	State(mut redis): State<ConnectionManager>,
+	Json(origin): Json<Origin>,
+) -> Result<(), AppError> {
+	let key = origin_key(&id);
+
+	// Make sure the contents haven't changed
+	// TODO make a LUA script to do this all in one operation.
+	let payload: Option<String> = redis.get(&key).await?;
+	let payload = payload.ok_or(AppError::NotFound)?;
+	let expected: Origin = serde_json::from_str(&payload)?;
+
+	if expected != origin {
+		return Err(AppError::Duplicate);
+	}
+
+	// Reset the timeout to 10 minutes.
+	match redis.expire(key, 600).await? {
+		0 => Err(AppError::NotFound),
+		_ => Ok(()),
+	}
+}
+
+fn origin_key(id: &str) -> String {
+	format!("origin.{}", id)
+}
+
+#[derive(thiserror::Error, Debug)]
+enum AppError {
+	#[error("redis error")]
+	Redis(#[from] redis::RedisError),
+
+	#[error("json error")]
+	Json(#[from] serde_json::Error),
+
+	#[error("not found")]
+	NotFound,
+
+	#[error("duplicate ID")]
+	Duplicate,
+}
+
+// Tell axum how to convert `AppError` into a response.
+impl IntoResponse for AppError {
+	fn into_response(self) -> Response {
+		match self {
+			AppError::Redis(e) => (StatusCode::INTERNAL_SERVER_ERROR, format!("redis error: {}", e)).into_response(),
+			AppError::Json(e) => (StatusCode::INTERNAL_SERVER_ERROR, format!("json error: {}", e)).into_response(),
+			AppError::NotFound => StatusCode::NOT_FOUND.into_response(),
+			AppError::Duplicate => StatusCode::CONFLICT.into_response(),
+		}
+	}
+}

moq-demo/Cargo.toml

@@ -1,42 +0,0 @@
-[package]
-name = "moq-demo"
-description = "Media over QUIC"
-authors = ["Luke Curley"]
-repository = "https://github.com/kixelated/moq-rs"
-license = "MIT OR Apache-2.0"
-
-version = "0.1.0"
-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]
-moq-transport = { path = "../moq-transport" }
-moq-transport-quinn = { path = "../moq-transport-quinn" }
-moq-warp = { path = "../moq-warp" }
-
-# QUIC
-quinn = "0.10"
-webtransport-quinn = "0.4.2"
-
-# Crypto
-ring = "0.16.20"
-rustls = "0.21.2"
-rustls-pemfile = "1.0.2"
-
-# Async stuff
-tokio = { version = "1.27", features = ["full"] }
-
-# Web server to serve the fingerprint
-warp = { version = "0.3.3", features = ["tls"] }
-hex = "0.4.3"
-
-# Logging
-clap = { version = "4.0", features = ["derive"] }
-log = { version = "0.4", features = ["std"] }
-env_logger = "0.9.3"
-anyhow = "1.0.70"

moq-demo/src/main.rs

@@ -1,84 +0,0 @@
-use std::{fs, io, net, path, sync};
-
-use anyhow::Context;
-use clap::Parser;
-use ring::digest::{digest, SHA256};
-use warp::Filter;
-
-mod server;
-use server::*;
-
-/// Search for a pattern in a file and display the lines that contain it.
-#[derive(Parser, Clone)]
-struct Cli {
-	/// Listen on this address
-	#[arg(short, long, default_value = "[::]:4443")]
-	addr: net::SocketAddr,
-
-	/// Use the certificate file at this path
-	#[arg(short, long, default_value = "cert/localhost.crt")]
-	cert: path::PathBuf,
-
-	/// Use the private key at this path
-	#[arg(short, long, default_value = "cert/localhost.key")]
-	key: path::PathBuf,
-}
-
-#[tokio::main]
-async fn main() -> anyhow::Result<()> {
-	env_logger::init();
-
-	let args = Cli::parse();
-
-	// Create a web server to serve the fingerprint
-	let serve = serve_http(args.clone());
-
-	// Create a server to actually serve the media
-	let config = ServerConfig {
-		addr: args.addr,
-		cert: args.cert,
-		key: args.key,
-	};
-
-	let server = Server::new(config).context("failed to create server")?;
-
-	// Run all of the above
-	tokio::select! {
-		res = server.run() => res.context("failed to run server"),
-		res = serve => res.context("failed to run HTTP server"),
-	}
-}
-
-// Run a HTTP server using Warp
-// TODO remove this when Chrome adds support for self-signed certificates using WebTransport
-async fn serve_http(args: Cli) -> anyhow::Result<()> {
-	// Read the PEM certificate file
-	let crt = fs::File::open(&args.cert)?;
-	let mut crt = io::BufReader::new(crt);
-
-	// Parse the DER certificate
-	let certs = rustls_pemfile::certs(&mut crt)?;
-	let cert = certs.first().expect("no certificate found");
-
-	// Compute the SHA-256 digest
-	let fingerprint = digest(&SHA256, cert.as_ref());
-	let fingerprint = hex::encode(fingerprint.as_ref());
-	let fingerprint = sync::Arc::new(fingerprint);
-
-	let cors = warp::cors().allow_any_origin();
-
-	// What an annoyingly complicated way to serve a static String
-	// I spent a long time trying to find the exact way of cloning and dereferencing the Arc.
-	let routes = warp::path!("fingerprint")
-		.map(move || (*(fingerprint.clone())).clone())
-		.with(cors);
-
-	warp::serve(routes)
-		.tls()
-		.cert_path(args.cert)
-		.key_path(args.key)
-		.run(args.addr)
-		.await;
-
-	Ok(())
-}

moq-demo/src/server.rs

@@ -1,117 +0,0 @@
-use moq_warp::relay::broker;
-
-use std::{fs, io, net, path, sync, time};
-
-use anyhow::Context;
-
-use tokio::task::JoinSet;
-
-pub struct Server {
-	server: quinn::Endpoint,
-
-	// The media sources.
-	broker: broker::Broadcasts,
-
-	// The active connections.
-	conns: JoinSet<anyhow::Result<()>>,
-}
-
-pub struct ServerConfig {
-	pub addr: net::SocketAddr,
-	pub cert: path::PathBuf,
-	pub key: path::PathBuf,
-}
-
-impl Server {
-	// Create a new server
-	pub fn new(config: ServerConfig) -> anyhow::Result<Self> {
-		// Read the PEM certificate chain
-		let certs = fs::File::open(config.cert).context("failed to open cert file")?;
-		let mut certs = io::BufReader::new(certs);
-		let certs = rustls_pemfile::certs(&mut certs)?
-			.into_iter()
-			.map(rustls::Certificate)
-			.collect();
-
-		// Read the PEM private key
-		let keys = fs::File::open(config.key).context("failed to open key file")?;
-		let mut keys = io::BufReader::new(keys);
-		let mut keys = rustls_pemfile::pkcs8_private_keys(&mut keys)?;
-
-		anyhow::ensure!(keys.len() == 1, "expected a single key");
-		let key = rustls::PrivateKey(keys.remove(0));
-
-		let mut tls_config = rustls::ServerConfig::builder()
-			.with_safe_default_cipher_suites()
-			.with_safe_default_kx_groups()
-			.with_protocol_versions(&[&rustls::version::TLS13])
-			.unwrap()
-			.with_no_client_auth()
-			.with_single_cert(certs, key)?;
-
-		tls_config.max_early_data_size = u32::MAX;
-		tls_config.alpn_protocols = vec![webtransport_quinn::ALPN.to_vec()];
-
-		let mut server_config = quinn::ServerConfig::with_crypto(sync::Arc::new(tls_config));
-
-		// Enable BBR congestion control
-		// TODO validate the implementation
-		let mut transport_config = quinn::TransportConfig::default();
-		transport_config.keep_alive_interval(Some(time::Duration::from_secs(2)));
-		transport_config.congestion_controller_factory(sync::Arc::new(quinn::congestion::BbrConfig::default()));
-
-		server_config.transport = sync::Arc::new(transport_config);
-		let server = quinn::Endpoint::server(server_config, config.addr)?;
-		let broker = broker::Broadcasts::new();
-
-		let conns = JoinSet::new();
-
-		Ok(Self { server, broker, conns })
-	}
-
-	pub async fn run(mut self) -> anyhow::Result<()> {
-		loop {
-			tokio::select! {
-				res = self.server.accept() => {
-					let conn = res.context("failed to accept QUIC connection")?;
-					let broker = self.broker.clone();
-
-					self.conns.spawn(async move { Self::handle(conn, broker).await });
-				},
-				res = self.conns.join_next(), if !self.conns.is_empty() => {
-					let res = res.expect("no tasks").expect("task aborted");
-					if let Err(err) = res {
-						log::error!("connection terminated: {:?}", err);
-					}
-				},
-			}
-		}
-	}
-
-	async fn handle(conn: quinn::Connecting, broker: broker::Broadcasts) -> anyhow::Result<()> {
-		// Wait for the QUIC connection to be established.
-		let conn = conn.await.context("failed to establish QUIC connection")?;
-
-		// Wait for the CONNECT request.
-		let request = webtransport_quinn::accept(conn)
-			.await
-			.context("failed to receive WebTransport request")?;
-
-		// TODO parse the request URI
-
-		// Accept the CONNECT request.
-		let session = request
-			.ok()
-			.await
-			.context("failed to respond to WebTransport request")?;
-
-		// Perform the MoQ handshake.
-		let session = moq_transport_quinn::accept(session, moq_transport::Role::Both)
-			.await
-			.context("failed to perform MoQ handshake")?;
-
-		// Run the relay code.
-		let session = moq_warp::relay::Session::new(session, broker);
-		session.run().await
-	}
-}

moq-pub/Cargo.toml

@@ -0,0 +1,47 @@
+[package]
+name = "moq-pub"
+description = "Media over QUIC"
+authors = ["Mike English", "Luke Curley"]
+repository = "https://github.com/kixelated/moq-rs"
+license = "MIT OR Apache-2.0"
+
+version = "0.1.0"
+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]
+moq-transport = { path = "../moq-transport" }
+
+# QUIC
+quinn = "0.10"
+webtransport-quinn = "0.6"
+#webtransport-quinn = { path = "../../webtransport-rs/webtransport-quinn" }
+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"
+
+[build-dependencies]
+clap = { version = "4", features = ["derive"] }
+clap_mangen = "0.2"
+url = "2"

moq-pub/README.md

@@ -0,0 +1,28 @@
+# moq-pub
+
+A command line tool for publishing media via Media over QUIC (MoQ).
+
+Expects to receive fragmented MP4 via standard input and connect to a MOQT relay.
+
+```
+ffmpeg ... - | moq-pub https://localhost:4443
+```
+
+### Invoking `moq-pub`:
+
+Here's how I'm currently testing things, with a local copy of Big Buck Bunny named `bbb_source.mp4`:
+
+```
+$ ffmpeg -hide_banner -v quiet -stream_loop -1 -re -i bbb_source.mp4 -an -f mp4 -movflags empty_moov+frag_every_frame+separate_moof+omit_tfhd_offset - | RUST_LOG=moq_pub=info moq-pub https://localhost:4443
+```
+
+This relies on having `moq-relay` (the relay server) already running locally in another shell.
+
+Note also that we're dropping the audio track (`-an`) above until audio playback is stabilized on the `moq-js` side.
+
+### Known issues
+
+-   Expects only one H.264/AVC1-encoded video track (catalog generation doesn't support audio tracks yet)
+-   Doesn't yet gracefully handle EOF - workaround: never stop sending it media (`-stream_loop -1`)
+-   Probably still full of lots of bugs
+-   Various other TODOs you can find in the code

moq-pub/build.rs

@@ -0,0 +1,15 @@
+include!("src/cli.rs");
+
+use clap::CommandFactory;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+	let out_dir = std::path::PathBuf::from(
+		std::env::var_os("OUT_DIR").ok_or(std::io::Error::new(std::io::ErrorKind::NotFound, "OUT_DIR not found"))?,
+	);
+	let cmd = Config::command();
+	let man = clap_mangen::Man::new(cmd);
+	let mut buffer: Vec<u8> = Default::default();
+	man.render(&mut buffer)?;
+	std::fs::write(out_dir.join("moq-pub.1"), buffer)?;
+	Ok(())
+}

moq-pub/src/cli.rs

@@ -0,0 +1,48 @@
+use clap::Parser;
+use std::{net, path};
+use url::Url;
+
+#[derive(Parser, Clone, Debug)]
+pub struct Config {
+	/// Listen for UDP packets on the given address.
+	#[arg(long, default_value = "[::]:0")]
+	pub bind: net::SocketAddr,
+
+	/// Advertise this frame rate in the catalog (informational)
+	// TODO auto-detect this from the input when not provided
+	#[arg(long, default_value = "24")]
+	pub fps: u8,
+
+	/// Advertise this bit rate in the catalog (informational)
+	// TODO auto-detect this from the input when not provided
+	#[arg(long, default_value = "1500000")]
+	pub bitrate: u32,
+
+	/// Connect to the given URL starting with https://
+	#[arg(value_parser = moq_url)]
+	pub url: Url,
+
+	/// Use the TLS root CA at this path, encoded as PEM.
+	///
+	/// This value can be provided multiple times for multiple roots.
+	/// If this is empty, system roots will be used instead
+	#[arg(long)]
+	pub tls_root: Vec<path::PathBuf>,
+
+	/// Danger: Disable TLS certificate verification.
+	///
+	/// Fine for local development, but should be used in caution in production.
+	#[arg(long)]
+	pub tls_disable_verify: bool,
+}
+
+fn moq_url(s: &str) -> Result<Url, String> {
+	let url = Url::try_from(s).map_err(|e| e.to_string())?;
+
+	// Make sure the scheme is moq
+	if url.scheme() != "https" {
+		return Err("url scheme must be https:// for WebTransport".to_string());
+	}
+
+	Ok(url)
+}

moq-pub/src/main.rs

@@ -0,0 +1,107 @@
+use std::{fs, io, sync::Arc, time};
+
+use anyhow::Context;
+use clap::Parser;
+
+mod cli;
+use cli::*;
+
+mod media;
+use media::*;
+
+use moq_transport::cache::broadcast;
+
+// TODO: clap complete
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+	env_logger::init();
+
+	// Disable tracing so we don't get a bunch of Quinn spam.
+	let tracer = tracing_subscriber::FmtSubscriber::builder()
+		.with_max_level(tracing::Level::WARN)
+		.finish();
+	tracing::subscriber::set_global_default(tracer).unwrap();
+
+	let config = Config::parse();
+
+	let (publisher, subscriber) = broadcast::new("");
+	let mut media = Media::new(&config, publisher).await?;
+
+	// Create a list of acceptable root certificates.
+	let mut roots = rustls::RootCertStore::empty();
+
+	if config.tls_root.is_empty() {
+		// Add the platform's native root certificates.
+		for cert in rustls_native_certs::load_native_certs().context("could not load platform certs")? {
+			roots
+				.add(&rustls::Certificate(cert.0))
+				.context("failed to add root cert")?;
+		}
+	} else {
+		// Add the specified root certificates.
+		for root in &config.tls_root {
+			let root = fs::File::open(root).context("failed to open root cert file")?;
+			let mut root = io::BufReader::new(root);
+
+			let root = rustls_pemfile::certs(&mut root).context("failed to read root cert")?;
+			anyhow::ensure!(root.len() == 1, "expected a single root cert");
+			let root = rustls::Certificate(root[0].to_owned());
+
+			roots.add(&root).context("failed to add root cert")?;
+		}
+	}
+
+	let mut tls_config = rustls::ClientConfig::builder()
+		.with_safe_defaults()
+		.with_root_certificates(roots)
+		.with_no_client_auth();
+
+	// Allow disabling TLS verification altogether.
+	if config.tls_disable_verify {
+		let noop = NoCertificateVerification {};
+		tls_config.dangerous().set_certificate_verifier(Arc::new(noop));
+	}
+
+	tls_config.alpn_protocols = vec![webtransport_quinn::ALPN.to_vec()]; // this one is important
+
+	let arc_tls_config = std::sync::Arc::new(tls_config);
+	let quinn_client_config = quinn::ClientConfig::new(arc_tls_config);
+
+	let mut endpoint = quinn::Endpoint::client(config.bind)?;
+	endpoint.set_default_client_config(quinn_client_config);
+
+	log::info!("connecting to relay: url={}", config.url);
+
+	let session = webtransport_quinn::connect(&endpoint, &config.url)
+		.await
+		.context("failed to create WebTransport session")?;
+
+	let session = moq_transport::session::Client::publisher(session, subscriber)
+		.await
+		.context("failed to create MoQ Transport session")?;
+
+	// TODO run a task that returns a 404 for all unknown subscriptions.
+	tokio::select! {
+		res = session.run() => res.context("session error")?,
+		res = media.run() => res.context("media error")?,
+	}
+
+	Ok(())
+}
+
+pub struct NoCertificateVerification {}
+
+impl rustls::client::ServerCertVerifier for NoCertificateVerification {
+	fn verify_server_cert(
+		&self,
+		_end_entity: &rustls::Certificate,
+		_intermediates: &[rustls::Certificate],
+		_server_name: &rustls::ServerName,
+		_scts: &mut dyn Iterator<Item = &[u8]>,
+		_ocsp_response: &[u8],
+		_now: time::SystemTime,
+	) -> Result<rustls::client::ServerCertVerified, rustls::Error> {
+		Ok(rustls::client::ServerCertVerified::assertion())
+	}
+}

moq-pub/src/media.rs

@@ -0,0 +1,430 @@
+use crate::cli::Config;
+use anyhow::{self, Context};
+use moq_transport::cache::{broadcast, fragment, segment, track};
+use moq_transport::VarInt;
+use mp4::{self, ReadBox};
+use serde_json::json;
+use std::cmp::max;
+use std::collections::HashMap;
+use std::io::Cursor;
+use std::time;
+use tokio::io::AsyncReadExt;
+
+pub struct Media {
+	// We hold on to publisher so we don't close then while media is still being published.
+	_broadcast: broadcast::Publisher,
+	_catalog: track::Publisher,
+	_init: track::Publisher,
+
+	// Tracks based on their track ID.
+	tracks: HashMap<u32, Track>,
+}
+
+impl Media {
+	pub async fn new(_config: &Config, mut broadcast: broadcast::Publisher) -> anyhow::Result<Self> {
+		let mut stdin = tokio::io::stdin();
+		let ftyp = read_atom(&mut stdin).await?;
+		anyhow::ensure!(&ftyp[4..8] == b"ftyp", "expected ftyp atom");
+
+		let moov = read_atom(&mut stdin).await?;
+		anyhow::ensure!(&moov[4..8] == b"moov", "expected moov atom");
+
+		let mut init = ftyp;
+		init.extend(&moov);
+
+		// We're going to parse the moov box.
+		// We have to read the moov box header to correctly advance the cursor for the mp4 crate.
+		let mut moov_reader = Cursor::new(&moov);
+		let moov_header = mp4::BoxHeader::read(&mut moov_reader)?;
+
+		// Parse the moov box so we can detect the timescales for each track.
+		let moov = mp4::MoovBox::read_box(&mut moov_reader, moov_header.size)?;
+
+		// Create the catalog track with a single segment.
+		let mut init_track = broadcast.create_track("0.mp4")?;
+		let mut init_segment = init_track.create_segment(segment::Info {
+			sequence: VarInt::ZERO,
+			priority: 0,
+			expires: None,
+		})?;
+
+		// Create a single fragment, optionally setting the size
+		let mut init_fragment = init_segment.create_fragment(fragment::Info {
+			sequence: VarInt::ZERO,
+			size: None, // size is only needed when we have multiple fragments.
+		})?;
+
+		init_fragment.write_chunk(init.into())?;
+
+		let mut tracks = HashMap::new();
+
+		for trak in &moov.traks {
+			let id = trak.tkhd.track_id;
+			let name = format!("{}.m4s", id);
+
+			let timescale = track_timescale(&moov, id);
+
+			// Store the track publisher in a map so we can update it later.
+			let track = broadcast.create_track(&name)?;
+			let track = Track::new(track, timescale);
+			tracks.insert(id, track);
+		}
+
+		let mut catalog = broadcast.create_track(".catalog")?;
+
+		// Create the catalog track
+		Self::serve_catalog(&mut catalog, &init_track.name, &moov)?;
+
+		Ok(Media {
+			_broadcast: broadcast,
+			_catalog: catalog,
+			_init: init_track,
+			tracks,
+		})
+	}
+
+	pub async fn run(&mut self) -> anyhow::Result<()> {
+		let mut stdin = tokio::io::stdin();
+		// The current track name
+		let mut current = None;
+
+		loop {
+			let atom = read_atom(&mut stdin).await?;
+
+			let mut reader = Cursor::new(&atom);
+			let header = mp4::BoxHeader::read(&mut reader)?;
+
+			match header.name {
+				mp4::BoxType::MoofBox => {
+					let moof = mp4::MoofBox::read_box(&mut reader, header.size).context("failed to read MP4")?;
+
+					// Process the moof.
+					let fragment = Fragment::new(moof)?;
+
+					// Get the track for this moof.
+					let track = self.tracks.get_mut(&fragment.track).context("failed to find track")?;
+
+					// Save the track ID for the next iteration, which must be a mdat.
+					anyhow::ensure!(current.is_none(), "multiple moof atoms");
+					current.replace(fragment.track);
+
+					// Publish the moof header, creating a new segment if it's a keyframe.
+					track.header(atom, fragment).context("failed to publish moof")?;
+				}
+				mp4::BoxType::MdatBox => {
+					// Get the track ID from the previous moof.
+					let track = current.take().context("missing moof")?;
+					let track = self.tracks.get_mut(&track).context("failed to find track")?;
+
+					// Publish the mdat atom.
+					track.data(atom).context("failed to publish mdat")?;
+				}
+
+				_ => {
+					// Skip unknown atoms
+				}
+			}
+		}
+	}
+
+	fn serve_catalog(
+		track: &mut track::Publisher,
+		init_track_name: &str,
+		moov: &mp4::MoovBox,
+	) -> Result<(), anyhow::Error> {
+		let mut segment = track.create_segment(segment::Info {
+			sequence: VarInt::ZERO,
+			priority: 0,
+			expires: None,
+		})?;
+
+		let mut tracks = Vec::new();
+
+		for trak in &moov.traks {
+			let mut track = json!({
+				"container": "mp4",
+				"init_track": init_track_name,
+				"data_track": format!("{}.m4s", trak.tkhd.track_id),
+			});
+
+			let stsd = &trak.mdia.minf.stbl.stsd;
+			if let Some(avc1) = &stsd.avc1 {
+				// avc1[.PPCCLL]
+				//
+				// let profile = 0x64;
+				// let constraints = 0x00;
+				// let level = 0x1f;
+				let profile = avc1.avcc.avc_profile_indication;
+				let constraints = avc1.avcc.profile_compatibility; // Not 100% certain here, but it's 0x00 on my current test video
+				let level = avc1.avcc.avc_level_indication;
+
+				let width = avc1.width;
+				let height = avc1.height;
+
+				let codec = rfc6381_codec::Codec::avc1(profile, constraints, level);
+				let codec_str = codec.to_string();
+
+				track["kind"] = json!("video");
+				track["codec"] = json!(codec_str);
+				track["width"] = json!(width);
+				track["height"] = json!(height);
+			} else if let Some(_hev1) = &stsd.hev1 {
+				// TODO https://github.com/gpac/mp4box.js/blob/325741b592d910297bf609bc7c400fc76101077b/src/box-codecs.js#L106
+				anyhow::bail!("HEVC not yet supported")
+			} else if let Some(mp4a) = &stsd.mp4a {
+				let desc = &mp4a
+					.esds
+					.as_ref()
+					.context("missing esds box for MP4a")?
+					.es_desc
+					.dec_config;
+				let codec_str = format!("mp4a.{:02x}.{}", desc.object_type_indication, desc.dec_specific.profile);
+
+				track["kind"] = json!("audio");
+				track["codec"] = json!(codec_str);
+				track["channel_count"] = json!(mp4a.channelcount);
+				track["sample_rate"] = json!(mp4a.samplerate.value());
+				track["sample_size"] = json!(mp4a.samplesize);
+
+				let bitrate = max(desc.max_bitrate, desc.avg_bitrate);
+				if bitrate > 0 {
+					track["bit_rate"] = json!(bitrate);
+				}
+			} else if let Some(vp09) = &stsd.vp09 {
+				// https://github.com/gpac/mp4box.js/blob/325741b592d910297bf609bc7c400fc76101077b/src/box-codecs.js#L238
+				let vpcc = &vp09.vpcc;
+				let codec_str = format!("vp09.0.{:02x}.{:02x}.{:02x}", vpcc.profile, vpcc.level, vpcc.bit_depth);
+
+				track["kind"] = json!("video");
+				track["codec"] = json!(codec_str);
+				track["width"] = json!(vp09.width); // no idea if this needs to be multiplied
+				track["height"] = json!(vp09.height); // no idea if this needs to be multiplied
+
+				// TODO Test if this actually works; I'm just guessing based on mp4box.js
+				anyhow::bail!("VP9 not yet supported")
+			} else {
+				// TODO add av01 support: https://github.com/gpac/mp4box.js/blob/325741b592d910297bf609bc7c400fc76101077b/src/box-codecs.js#L251
+				anyhow::bail!("unknown codec for track: {}", trak.tkhd.track_id);
+			}
+
+			tracks.push(track);
+		}
+
+		let catalog = json!({
+			"tracks": tracks
+		});
+
+		let catalog_str = serde_json::to_string_pretty(&catalog)?;
+		log::info!("catalog: {}", catalog_str);
+
+		// Create a single fragment for the segment.
+		let mut fragment = segment.create_fragment(fragment::Info {
+			sequence: VarInt::ZERO,
+			size: None, // Size is only needed when we have multiple fragments.
+		})?;
+
+		// Add the segment and add the fragment.
+		fragment.write_chunk(catalog_str.into())?;
+
+		Ok(())
+	}
+}
+
+// Read a full MP4 atom into a vector.
+async fn read_atom<R: AsyncReadExt + Unpin>(reader: &mut R) -> anyhow::Result<Vec<u8>> {
+	// Read the 8 bytes for the size + type
+	let mut buf = [0u8; 8];
+	reader.read_exact(&mut buf).await?;
+
+	// Convert the first 4 bytes into the size.
+	let size = u32::from_be_bytes(buf[0..4].try_into()?) as u64;
+
+	let mut raw = buf.to_vec();
+
+	let mut limit = match size {
+		// Runs until the end of the file.
+		0 => reader.take(u64::MAX),
+
+		// The next 8 bytes are the extended size to be used instead.
+		1 => {
+			reader.read_exact(&mut buf).await?;
+			let size_large = u64::from_be_bytes(buf);
+			anyhow::ensure!(size_large >= 16, "impossible extended box size: {}", size_large);
+
+			reader.take(size_large - 16)
+		}
+
+		2..=7 => {
+			anyhow::bail!("impossible box size: {}", size)
+		}
+
+		size => reader.take(size - 8),
+	};
+
+	// Append to the vector and return it.
+	let _read_bytes = limit.read_to_end(&mut raw).await?;
+
+	Ok(raw)
+}
+
+struct Track {
+	// The track we're producing
+	track: track::Publisher,
+
+	// The current segment
+	current: Option<fragment::Publisher>,
+
+	// The number of units per second.
+	timescale: u64,
+
+	// The number of segments produced.
+	sequence: u64,
+}
+
+impl Track {
+	fn new(track: track::Publisher, timescale: u64) -> Self {
+		Self {
+			track,
+			sequence: 0,
+			current: None,
+			timescale,
+		}
+	}
+
+	pub fn header(&mut self, raw: Vec<u8>, fragment: Fragment) -> anyhow::Result<()> {
+		if let Some(current) = self.current.as_mut() {
+			if !fragment.keyframe {
+				// Use the existing segment
+				current.write_chunk(raw.into())?;
+				return Ok(());
+			}
+		}
+
+		// Otherwise make a new segment
+
+		// Compute the timestamp in milliseconds.
+		// Overflows after 583 million years, so we're fine.
+		let timestamp: u32 = fragment
+			.timestamp(self.timescale)
+			.as_millis()
+			.try_into()
+			.context("timestamp too large")?;
+
+		// Create a new segment.
+		let mut segment = self.track.create_segment(segment::Info {
+			sequence: VarInt::try_from(self.sequence).context("sequence too large")?,
+
+			// Newer segments are higher priority
+			priority: u32::MAX.checked_sub(timestamp).context("priority too large")?,
+
+			// Delete segments after 10s.
+			expires: Some(time::Duration::from_secs(10)),
+		})?;
+
+		// Create a single fragment for the segment that we will keep appending.
+		let mut fragment = segment.create_fragment(fragment::Info {
+			sequence: VarInt::ZERO,
+			size: None,
+		})?;
+
+		self.sequence += 1;
+
+		// Insert the raw atom into the segment.
+		fragment.write_chunk(raw.into())?;
+
+		// Save for the next iteration
+		self.current = Some(fragment);
+
+		Ok(())
+	}
+
+	pub fn data(&mut self, raw: Vec<u8>) -> anyhow::Result<()> {
+		let fragment = self.current.as_mut().context("missing current fragment")?;
+		fragment.write_chunk(raw.into())?;
+
+		Ok(())
+	}
+}
+
+struct Fragment {
+	// The track for this fragment.
+	track: u32,
+
+	// The timestamp of the first sample in this fragment, in timescale units.
+	timestamp: u64,
+
+	// True if this fragment is a keyframe.
+	keyframe: bool,
+}
+
+impl Fragment {
+	fn new(moof: mp4::MoofBox) -> anyhow::Result<Self> {
+		// We can't split the mdat atom, so this is impossible to support
+		anyhow::ensure!(moof.trafs.len() == 1, "multiple tracks per moof atom");
+		let track = moof.trafs[0].tfhd.track_id;
+
+		// Parse the moof to get some timing information to sleep.
+		let timestamp = sample_timestamp(&moof).expect("couldn't find timestamp");
+
+		// Detect if we should start a new segment.
+		let keyframe = sample_keyframe(&moof);
+
+		Ok(Self {
+			track,
+			timestamp,
+			keyframe,
+		})
+	}
+
+	// Convert from timescale units to a duration.
+	fn timestamp(&self, timescale: u64) -> time::Duration {
+		time::Duration::from_millis(1000 * self.timestamp / timescale)
+	}
+}
+
+fn sample_timestamp(moof: &mp4::MoofBox) -> Option<u64> {
+	Some(moof.trafs.first()?.tfdt.as_ref()?.base_media_decode_time)
+}
+
+fn sample_keyframe(moof: &mp4::MoofBox) -> bool {
+	for traf in &moof.trafs {
+		// TODO trak default flags if this is None
+		let default_flags = traf.tfhd.default_sample_flags.unwrap_or_default();
+		let trun = match &traf.trun {
+			Some(t) => t,
+			None => return false,
+		};
+
+		for i in 0..trun.sample_count {
+			let mut flags = match trun.sample_flags.get(i as usize) {
+				Some(f) => *f,
+				None => default_flags,
+			};
+
+			if i == 0 && trun.first_sample_flags.is_some() {
+				flags = trun.first_sample_flags.unwrap();
+			}
+
+			// https://chromium.googlesource.com/chromium/src/media/+/master/formats/mp4/track_run_iterator.cc#177
+			let keyframe = (flags >> 24) & 0x3 == 0x2; // kSampleDependsOnNoOther
+			let non_sync = (flags >> 16) & 0x1 == 0x1; // kSampleIsNonSyncSample
+
+			if keyframe && !non_sync {
+				return true;
+			}
+		}
+	}
+
+	false
+}
+
+// Find the timescale for the given track.
+fn track_timescale(moov: &mp4::MoovBox, track_id: u32) -> u64 {
+	let trak = moov
+		.traks
+		.iter()
+		.find(|trak| trak.tkhd.track_id == track_id)
+		.expect("failed to find trak");
+
+	trak.mdia.mdhd.timescale as u64
+}

moq-relay/Cargo.toml

@@ -0,0 +1,51 @@
+[package]
+name = "moq-relay"
+description = "Media over QUIC"
+authors = ["Luke Curley"]
+repository = "https://github.com/kixelated/moq-rs"
+license = "MIT OR Apache-2.0"
+
+version = "0.1.0"
+edition = "2021"
+
+keywords = ["quic", "http3", "webtransport", "media", "live"]
+categories = ["multimedia", "network-programming", "web-programming"]
+
+[dependencies]
+moq-transport = { path = "../moq-transport" }
+moq-api = { path = "../moq-api" }
+
+# QUIC
+quinn = "0.10"
+webtransport-quinn = "0.6"
+#webtransport-quinn = { path = "../../webtransport-rs/webtransport-quinn" }
+url = "2"
+
+# Crypto
+ring = "0.16"
+rustls = { version = "0.21", features = ["dangerous_configuration"] }
+rustls-pemfile = "1"
+rustls-native-certs = "0.6"
+webpki = "0.22"
+
+# Async stuff
+tokio = { version = "1", features = ["full"] }
+
+# Web server to serve the fingerprint
+axum = { version = "0.6", features = ["tokio"] }
+axum-server = { version = "0.5", features = ["tls-rustls"] }
+hex = "0.4"
+tower-http = { version = "0.4", features = ["cors"] }
+
+# Error handling
+anyhow = { version = "1", features = ["backtrace"] }
+thiserror = "1"
+
+# CLI
+clap = { version = "4", features = ["derive"] }
+
+# Logging
+log = { version = "0.4", features = ["std"] }
+env_logger = "0.9"
+tracing = "0.1"
+tracing-subscriber = "0.3"

moq-relay/README.md

@@ -0,0 +1,17 @@
+# moq-relay
+
+A server that connects publishing clients to subscribing clients.
+All subscriptions are deduplicated and cached, so that a single publisher can serve many subscribers.
+
+## Usage
+
+The publisher must choose a unique name for their broadcast, sent as the WebTransport path when connecting to the server.
+We currently do a dumb string comparison, so capatilization matters as do slashes.
+
+For example: `CONNECT https://relay.quic.video/BigBuckBunny`
+
+The MoqTransport handshake includes a `role` parameter, which must be `publisher` or `subscriber`.
+The specification allows a `both` role but you'll get an error.
+
+You can have one publisher and any number of subscribers connected to the same path.
+If the publisher disconnects, then all subscribers receive an error and will not get updates, even if a new publisher reuses the path.

moq-relay/src/config.rs

@@ -0,0 +1,55 @@
+use std::{net, path};
+use url::Url;
+
+use clap::Parser;
+
+/// Search for a pattern in a file and display the lines that contain it.
+#[derive(Parser, Clone)]
+pub struct Config {
+	/// Listen on this address
+	#[arg(long, default_value = "[::]:4443")]
+	pub listen: net::SocketAddr,
+
+	/// Use the certificates at this path, encoded as PEM.
+	///
+	/// You can use this option multiple times for multiple certificates.
+	/// The first match for the provided SNI will be used, otherwise the last cert will be used.
+	/// You also need to provide the private key multiple times via `key``.
+	#[arg(long)]
+	pub tls_cert: Vec<path::PathBuf>,
+
+	/// Use the private key at this path, encoded as PEM.
+	///
+	/// There must be a key for every certificate provided via `cert`.
+	#[arg(long)]
+	pub tls_key: Vec<path::PathBuf>,
+
+	/// Use the TLS root at this path, encoded as PEM.
+	///
+	/// This value can be provided multiple times for multiple roots.
+	/// If this is empty, system roots will be used instead
+	#[arg(long)]
+	pub tls_root: Vec<path::PathBuf>,
+
+	/// Danger: Disable TLS certificate verification.
+	///
+	/// Fine for local development and between relays, but should be used in caution in production.
+	#[arg(long)]
+	pub tls_disable_verify: bool,
+
+	/// Optional: Use the moq-api via HTTP to store origin information.
+	#[arg(long)]
+	pub api: Option<Url>,
+
+	/// Our internal address which we advertise to other origins.
+	/// We use QUIC, so the certificate must be valid for this address.
+	/// This needs to be prefixed with https:// to use WebTransport.
+	/// This is only used when --api is set and only for publishing broadcasts.
+	#[arg(long)]
+	pub api_node: Option<Url>,
+
+	/// Enable development mode.
+	/// Currently, this only listens on HTTPS and serves /fingerprint, for self-signed certificates
+	#[arg(long, action)]
+	pub dev: bool,
+}

moq-relay/src/error.rs

@@ -0,0 +1,51 @@
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum RelayError {
+	#[error("transport error: {0}")]
+	Transport(#[from] moq_transport::session::SessionError),
+
+	#[error("cache error: {0}")]
+	Cache(#[from] moq_transport::cache::CacheError),
+
+	#[error("api error: {0}")]
+	MoqApi(#[from] moq_api::ApiError),
+
+	#[error("url error: {0}")]
+	Url(#[from] url::ParseError),
+
+	#[error("webtransport client error: {0}")]
+	WebTransportClient(#[from] webtransport_quinn::ClientError),
+
+	#[error("webtransport server error: {0}")]
+	WebTransportServer(#[from] webtransport_quinn::ServerError),
+
+	#[error("missing node")]
+	MissingNode,
+}
+
+impl moq_transport::MoqError for RelayError {
+	fn code(&self) -> u32 {
+		match self {
+			Self::Transport(err) => err.code(),
+			Self::Cache(err) => err.code(),
+			Self::MoqApi(_err) => 504,
+			Self::Url(_) => 500,
+			Self::MissingNode => 500,
+			Self::WebTransportClient(_) => 504,
+			Self::WebTransportServer(_) => 500,
+		}
+	}
+
+	fn reason(&self) -> String {
+		match self {
+			Self::Transport(err) => format!("transport error: {}", err.reason()),
+			Self::Cache(err) => format!("cache error: {}", err.reason()),
+			Self::MoqApi(err) => format!("api error: {}", err),
+			Self::Url(err) => format!("url error: {}", err),
+			Self::MissingNode => "missing node".to_owned(),
+			Self::WebTransportServer(err) => format!("upstream server error: {}", err),
+			Self::WebTransportClient(err) => format!("upstream client error: {}", err),
+		}
+	}
+}

moq-relay/src/main.rs

@@ -0,0 +1,51 @@
+use anyhow::Context;
+use clap::Parser;
+
+mod config;
+mod error;
+mod origin;
+mod quic;
+mod session;
+mod tls;
+mod web;
+
+pub use config::*;
+pub use error::*;
+pub use origin::*;
+pub use quic::*;
+pub use session::*;
+pub use tls::*;
+pub use web::*;
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+	env_logger::init();
+
+	// Disable tracing so we don't get a bunch of Quinn spam.
+	let tracer = tracing_subscriber::FmtSubscriber::builder()
+		.with_max_level(tracing::Level::WARN)
+		.finish();
+	tracing::subscriber::set_global_default(tracer).unwrap();
+
+	let config = Config::parse();
+	let tls = Tls::load(&config)?;
+
+	// Create a QUIC server for media.
+	let quic = Quic::new(config.clone(), tls.clone())
+		.await
+		.context("failed to create server")?;
+
+	// Create the web server if the --dev flag was set.
+	// This is currently only useful in local development so it's not enabled by default.
+	if config.dev {
+		let web = Web::new(config, tls);
+
+		// Unfortunately we can't use preconditions because Tokio still executes the branch; just ignore the result
+		tokio::select! {
+			res = quic.serve() => res.context("failed to run quic server"),
+			res = web.serve() => res.context("failed to run web server"),
+		}
+	} else {
+		quic.serve().await.context("failed to run quic server")
+	}
+}

moq-relay/src/origin.rs

@@ -0,0 +1,216 @@
+use std::ops::{Deref, DerefMut};
+use std::{
+	collections::HashMap,
+	sync::{Arc, Mutex, Weak},
+};
+
+use moq_api::ApiError;
+use moq_transport::cache::{broadcast, CacheError};
+use url::Url;
+
+use tokio::time;
+
+use crate::RelayError;
+
+#[derive(Clone)]
+pub struct Origin {
+	// An API client used to get/set broadcasts.
+	// If None then we never use a remote origin.
+	// TODO: Stub this out instead.
+	api: Option<moq_api::Client>,
+
+	// The internal address of our node.
+	// If None then we can never advertise ourselves as an origin.
+	// TODO: Stub this out instead.
+	node: Option<Url>,
+
+	// A map of active broadcasts by ID.
+	cache: Arc<Mutex<HashMap<String, Weak<Subscriber>>>>,
+
+	// A QUIC endpoint we'll use to fetch from other origins.
+	quic: quinn::Endpoint,
+}
+
+impl Origin {
+	pub fn new(api: Option<moq_api::Client>, node: Option<Url>, quic: quinn::Endpoint) -> Self {
+		Self {
+			api,
+			node,
+			cache: Default::default(),
+			quic,
+		}
+	}
+
+	/// Create a new broadcast with the given ID.
+	///
+	/// Publisher::run needs to be called to periodically refresh the origin cache.
+	pub async fn publish(&mut self, id: &str) -> Result<Publisher, RelayError> {
+		let (publisher, subscriber) = broadcast::new(id);
+
+		let subscriber = {
+			let mut cache = self.cache.lock().unwrap();
+
+			// Check if the broadcast already exists.
+			// TODO This is racey, because a new publisher could be created while existing subscribers are still active.
+			if cache.contains_key(id) {
+				return Err(CacheError::Duplicate.into());
+			}
+
+			// Create subscriber that will remove from the cache when dropped.
+			let subscriber = Arc::new(Subscriber {
+				broadcast: subscriber,
+				origin: self.clone(),
+			});
+
+			cache.insert(id.to_string(), Arc::downgrade(&subscriber));
+
+			subscriber
+		};
+
+		// Create a publisher that constantly updates itself as the origin in moq-api.
+		// It holds a reference to the subscriber to prevent dropping early.
+		let mut publisher = Publisher {
+			broadcast: publisher,
+			subscriber,
+			api: None,
+		};
+
+		// Insert the publisher into the database.
+		if let Some(api) = self.api.as_mut() {
+			// Make a URL for the broadcast.
+			let url = self.node.as_ref().ok_or(RelayError::MissingNode)?.clone().join(id)?;
+			let origin = moq_api::Origin { url };
+			api.set_origin(id, &origin).await?;
+
+			// Refresh every 5 minutes
+			publisher.api = Some((api.clone(), origin));
+		}
+
+		Ok(publisher)
+	}
+
+	pub fn subscribe(&self, id: &str) -> Arc<Subscriber> {
+		let mut cache = self.cache.lock().unwrap();
+
+		if let Some(broadcast) = cache.get(id) {
+			if let Some(broadcast) = broadcast.upgrade() {
+				return broadcast;
+			}
+		}
+
+		let (publisher, subscriber) = broadcast::new(id);
+		let subscriber = Arc::new(Subscriber {
+			broadcast: subscriber,
+			origin: self.clone(),
+		});
+
+		cache.insert(id.to_string(), Arc::downgrade(&subscriber));
+
+		let mut this = self.clone();
+		let id = id.to_string();
+
+		// Rather than fetching from the API and connecting via QUIC inline, we'll spawn a task to do it.
+		// This way we could stop polling this session and it won't impact other session.
+		// It also means we'll only connect the API and QUIC once if N subscribers suddenly show up.
+		// However, the downside is that we don't return an error immediately.
+		// If that's important, it can be done but it gets a bit racey.
+		tokio::spawn(async move {
+			if let Err(err) = this.serve(&id, publisher).await {
+				log::warn!("failed to serve remote broadcast: id={} err={}", id, err);
+			}
+		});
+
+		subscriber
+	}
+
+	async fn serve(&mut self, id: &str, publisher: broadcast::Publisher) -> Result<(), RelayError> {
+		log::debug!("finding origin: id={}", id);
+
+		// Fetch the origin from the API.
+		let origin = self
+			.api
+			.as_mut()
+			.ok_or(CacheError::NotFound)?
+			.get_origin(id)
+			.await?
+			.ok_or(CacheError::NotFound)?;
+
+		log::debug!("fetching from origin: id={} url={}", id, origin.url);
+
+		// Establish the webtransport session.
+		let session = webtransport_quinn::connect(&self.quic, &origin.url).await?;
+		let session = moq_transport::session::Client::subscriber(session, publisher).await?;
+
+		session.run().await?;
+
+		Ok(())
+	}
+}
+
+pub struct Subscriber {
+	pub broadcast: broadcast::Subscriber,
+
+	origin: Origin,
+}
+
+impl Drop for Subscriber {
+	fn drop(&mut self) {
+		self.origin.cache.lock().unwrap().remove(&self.broadcast.id);
+	}
+}
+
+impl Deref for Subscriber {
+	type Target = broadcast::Subscriber;
+
+	fn deref(&self) -> &Self::Target {
+		&self.broadcast
+	}
+}
+
+pub struct Publisher {
+	pub broadcast: broadcast::Publisher,
+
+	api: Option<(moq_api::Client, moq_api::Origin)>,
+
+	#[allow(dead_code)]
+	subscriber: Arc<Subscriber>,
+}
+
+impl Publisher {
+	pub async fn run(&mut self) -> Result<(), ApiError> {
+		// Every 5m tell the API we're still alive.
+		// TODO don't hard-code these values
+		let mut interval = time::interval(time::Duration::from_secs(60 * 5));
+
+		loop {
+			if let Some((api, origin)) = self.api.as_mut() {
+				api.patch_origin(&self.broadcast.id, origin).await?;
+			}
+
+			// TODO move to start of loop; this is just for testing
+			interval.tick().await;
+		}
+	}
+
+	pub async fn close(&mut self) -> Result<(), ApiError> {
+		if let Some((api, _)) = self.api.as_mut() {
+			api.delete_origin(&self.broadcast.id).await?;
+		}
+
+		Ok(())
+	}
+}
+
+impl Deref for Publisher {
+	type Target = broadcast::Publisher;
+
+	fn deref(&self) -> &Self::Target {
+		&self.broadcast
+	}
+}
+
+impl DerefMut for Publisher {
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		&mut self.broadcast
+	}
+}

moq-relay/src/quic.rs

@@ -0,0 +1,85 @@
+use std::{sync::Arc, time};
+
+use anyhow::Context;
+
+use tokio::task::JoinSet;
+
+use crate::{Config, Origin, Session, Tls};
+
+pub struct Quic {
+	quic: quinn::Endpoint,
+
+	// The active connections.
+	conns: JoinSet<anyhow::Result<()>>,
+
+	// The map of active broadcasts by path.
+	origin: Origin,
+}
+
+impl Quic {
+	// Create a QUIC endpoint that can be used for both clients and servers.
+	pub async fn new(config: Config, tls: Tls) -> anyhow::Result<Self> {
+		let mut client_config = tls.client.clone();
+		let mut server_config = tls.server.clone();
+		client_config.alpn_protocols = vec![webtransport_quinn::ALPN.to_vec()];
+		server_config.alpn_protocols = vec![webtransport_quinn::ALPN.to_vec()];
+
+		// Enable BBR congestion control
+		// TODO validate the implementation
+		let mut transport_config = quinn::TransportConfig::default();
+		transport_config.max_idle_timeout(Some(time::Duration::from_secs(10).try_into().unwrap()));
+		transport_config.keep_alive_interval(Some(time::Duration::from_secs(4))); // TODO make this smarter
+		transport_config.congestion_controller_factory(Arc::new(quinn::congestion::BbrConfig::default()));
+		transport_config.mtu_discovery_config(None); // Disable MTU discovery
+		let transport_config = Arc::new(transport_config);
+
+		let mut client_config = quinn::ClientConfig::new(Arc::new(client_config));
+		let mut server_config = quinn::ServerConfig::with_crypto(Arc::new(server_config));
+		server_config.transport_config(transport_config.clone());
+		client_config.transport_config(transport_config);
+
+		// There's a bit more boilerplate to make a generic endpoint.
+		let runtime = quinn::default_runtime().context("no async runtime")?;
+		let endpoint_config = quinn::EndpointConfig::default();
+		let socket = std::net::UdpSocket::bind(config.listen).context("failed to bind UDP socket")?;
+
+		// Create the generic QUIC endpoint.
+		let mut quic = quinn::Endpoint::new(endpoint_config, Some(server_config), socket, runtime)
+			.context("failed to create QUIC endpoint")?;
+		quic.set_default_client_config(client_config);
+
+		let api = config.api.map(|url| {
+			log::info!("using moq-api: url={}", url);
+			moq_api::Client::new(url)
+		});
+
+		if let Some(ref node) = config.api_node {
+			log::info!("advertising origin: url={}", node);
+		}
+
+		let origin = Origin::new(api, config.api_node, quic.clone());
+		let conns = JoinSet::new();
+
+		Ok(Self { quic, origin, conns })
+	}
+
+	pub async fn serve(mut self) -> anyhow::Result<()> {
+		log::info!("listening on {}", self.quic.local_addr()?);
+
+		loop {
+			tokio::select! {
+				res = self.quic.accept() => {
+					let conn = res.context("failed to accept QUIC connection")?;
+					let mut session = Session::new(self.origin.clone());
+					self.conns.spawn(async move { session.run(conn).await });
+				},
+				res = self.conns.join_next(), if !self.conns.is_empty() => {
+					let res = res.expect("no tasks").expect("task aborted");
+					if let Err(err) = res {
+						log::warn!("connection terminated: {:?}", err);
+					}
+				},
+			}
+		}
+	}
+}

moq-relay/src/session.rs

@@ -0,0 +1,111 @@
+use anyhow::Context;
+
+use moq_transport::{session::Request, setup::Role, MoqError};
+
+use crate::Origin;
+
+#[derive(Clone)]
+pub struct Session {
+	origin: Origin,
+}
+
+impl Session {
+	pub fn new(origin: Origin) -> Self {
+		Self { origin }
+	}
+
+	pub async fn run(&mut self, conn: quinn::Connecting) -> anyhow::Result<()> {
+		log::debug!("received QUIC handshake: ip={:?}", conn.remote_address());
+
+		// Wait for the QUIC connection to be established.
+		let conn = conn.await.context("failed to establish QUIC connection")?;
+
+		log::debug!(
+			"established QUIC connection: ip={:?} id={}",
+			conn.remote_address(),
+			conn.stable_id()
+		);
+		let id = conn.stable_id();
+
+		// Wait for the CONNECT request.
+		let request = webtransport_quinn::accept(conn)
+			.await
+			.context("failed to receive WebTransport request")?;
+
+		// Strip any leading and trailing slashes to get the broadcast name.
+		let path = request.url().path().trim_matches('/').to_string();
+
+		log::debug!("received WebTransport CONNECT: id={} path={}", id, path);
+
+		// Accept the CONNECT request.
+		let session = request
+			.ok()
+			.await
+			.context("failed to respond to WebTransport request")?;
+
+		// Perform the MoQ handshake.
+		let request = moq_transport::session::Server::accept(session)
+			.await
+			.context("failed to accept handshake")?;
+
+		log::debug!("received MoQ SETUP: id={} role={:?}", id, request.role());
+
+		let role = request.role();
+
+		match role {
+			Role::Publisher => {
+				if let Err(err) = self.serve_publisher(id, request, &path).await {
+					log::warn!("error serving publisher: id={} path={} err={:#?}", id, path, err);
+				}
+			}
+			Role::Subscriber => {
+				if let Err(err) = self.serve_subscriber(id, request, &path).await {
+					log::warn!("error serving subscriber: id={} path={} err={:#?}", id, path, err);
+				}
+			}
+			Role::Both => {
+				log::warn!("role both not supported: id={}", id);
+				request.reject(300);
+			}
+		};
+
+		log::debug!("closing connection: id={}", id);
+
+		Ok(())
+	}
+
+	async fn serve_publisher(&mut self, id: usize, request: Request, path: &str) -> anyhow::Result<()> {
+		log::info!("serving publisher: id={}, path={}", id, path);
+
+		let mut origin = match self.origin.publish(path).await {
+			Ok(origin) => origin,
+			Err(err) => {
+				request.reject(err.code());
+				return Err(err.into());
+			}
+		};
+
+		let session = request.subscriber(origin.broadcast.clone()).await?;
+
+		tokio::select! {
+			_ = session.run() => origin.close().await?,
+			_ = origin.run() => (), // TODO send error to session
+		};
+
+		Ok(())
+	}
+
+	async fn serve_subscriber(&mut self, id: usize, request: Request, path: &str) -> anyhow::Result<()> {
+		log::info!("serving subscriber: id={} path={}", id, path);
+
+		let subscriber = self.origin.subscribe(path);
+
+		let session = request.publisher(subscriber.broadcast.clone()).await?;
+		session.run().await?;
+
+		// Make sure this doesn't get dropped too early
+		drop(subscriber);
+
+		Ok(())
+	}
+}

moq-relay/src/tls.rs

@@ -0,0 +1,182 @@
+use anyhow::Context;
+use ring::digest::{digest, SHA256};
+use rustls::server::{ClientHello, ResolvesServerCert};
+use rustls::sign::CertifiedKey;
+use rustls::{Certificate, PrivateKey, RootCertStore};
+use std::io::{self, Cursor, Read};
+use std::path;
+use std::sync::Arc;
+use std::{fs, time};
+use webpki::{DnsNameRef, EndEntityCert};
+
+use crate::Config;
+
+#[derive(Clone)]
+pub struct Tls {
+	pub server: rustls::ServerConfig,
+	pub client: rustls::ClientConfig,
+	pub fingerprints: Vec<String>,
+}
+
+impl Tls {
+	pub fn load(config: &Config) -> anyhow::Result<Self> {
+		let mut serve = ServeCerts::default();
+
+		// Load the certificate and key files based on their index.
+		anyhow::ensure!(
+			config.tls_cert.len() == config.tls_key.len(),
+			"--tls-cert and --tls-key counts differ"
+		);
+		for (chain, key) in config.tls_cert.iter().zip(config.tls_key.iter()) {
+			serve.load(chain, key)?;
+		}
+
+		// Create a list of acceptable root certificates.
+		let mut roots = RootCertStore::empty();
+
+		if config.tls_root.is_empty() {
+			// Add the platform's native root certificates.
+			for cert in rustls_native_certs::load_native_certs().context("could not load platform certs")? {
+				roots.add(&Certificate(cert.0)).context("failed to add root cert")?;
+			}
+		} else {
+			// Add the specified root certificates.
+			for root in &config.tls_root {
+				let root = fs::File::open(root).context("failed to open root cert file")?;
+				let mut root = io::BufReader::new(root);
+				let root = rustls_pemfile::certs(&mut root).context("failed to read root cert")?;
+				anyhow::ensure!(root.len() == 1, "expected a single root cert");
+				let root = Certificate(root[0].to_owned());
+
+				roots.add(&root).context("failed to add root cert")?;
+			}
+		}
+
+		// Create the TLS configuration we'll use as a client (relay -> relay)
+		let mut client = rustls::ClientConfig::builder()
+			.with_safe_defaults()
+			.with_root_certificates(roots)
+			.with_no_client_auth();
+
+		// Allow disabling TLS verification altogether.
+		if config.tls_disable_verify {
+			let noop = NoCertificateVerification {};
+			client.dangerous().set_certificate_verifier(Arc::new(noop));
+		}
+
+		let fingerprints = serve.fingerprints();
+
+		// Create the TLS configuration we'll use as a server (relay <- browser)
+		let server = rustls::ServerConfig::builder()
+			.with_safe_defaults()
+			.with_no_client_auth()
+			.with_cert_resolver(Arc::new(serve));
+
+		let certs = Self {
+			server,
+			client,
+			fingerprints,
+		};
+
+		Ok(certs)
+	}
+}
+
+#[derive(Default)]
+struct ServeCerts {
+	list: Vec<Arc<CertifiedKey>>,
+}
+
+impl ServeCerts {
+	// Load a certificate and cooresponding key from a file
+	pub fn load(&mut self, chain: &path::PathBuf, key: &path::PathBuf) -> anyhow::Result<()> {
+		// Read the PEM certificate chain
+		let chain = fs::File::open(chain).context("failed to open cert file")?;
+		let mut chain = io::BufReader::new(chain);
+
+		let chain: Vec<Certificate> = rustls_pemfile::certs(&mut chain)?
+			.into_iter()
+			.map(Certificate)
+			.collect();
+
+		anyhow::ensure!(!chain.is_empty(), "could not find certificate");
+
+		// Read the PEM private key
+		let mut keys = fs::File::open(key).context("failed to open key file")?;
+
+		// Read the keys into a Vec so we can parse it twice.
+		let mut buf = Vec::new();
+		keys.read_to_end(&mut buf)?;
+
+		// Try to parse a PKCS#8 key
+		// -----BEGIN PRIVATE KEY-----
+		let mut keys = rustls_pemfile::pkcs8_private_keys(&mut Cursor::new(&buf))?;
+
+		// Try again but with EC keys this time
+		// -----BEGIN EC PRIVATE KEY-----
+		if keys.is_empty() {
+			keys = rustls_pemfile::ec_private_keys(&mut Cursor::new(&buf))?
+		};
+
+		anyhow::ensure!(!keys.is_empty(), "could not find private key");
+		anyhow::ensure!(keys.len() < 2, "expected a single key");
+
+		let key = PrivateKey(keys.remove(0));
+		let key = rustls::sign::any_supported_type(&key)?;
+
+		let certified = Arc::new(CertifiedKey::new(chain, key));
+		self.list.push(certified);
+
+		Ok(())
+	}
+
+	// Return the SHA256 fingerprint of our certificates.
+	pub fn fingerprints(&self) -> Vec<String> {
+		self.list
+			.iter()
+			.map(|ck| {
+				let fingerprint = digest(&SHA256, ck.cert[0].as_ref());
+				let fingerprint = hex::encode(fingerprint.as_ref());
+				fingerprint
+			})
+			.collect()
+	}
+}
+
+impl ResolvesServerCert for ServeCerts {
+	fn resolve(&self, client_hello: ClientHello<'_>) -> Option<Arc<CertifiedKey>> {
+		if let Some(name) = client_hello.server_name() {
+			if let Ok(dns_name) = DnsNameRef::try_from_ascii_str(name) {
+				for ck in &self.list {
+					// TODO I gave up on caching the parsed result because of lifetime hell.
+					// If this shows up on benchmarks, somebody should fix it.
+					let leaf = ck.cert.first().expect("missing certificate");
+					let parsed = EndEntityCert::try_from(leaf.0.as_ref()).expect("failed to parse certificate");
+
+					if parsed.verify_is_valid_for_dns_name(dns_name).is_ok() {
+						return Some(ck.clone());
+					}
+				}
+			}
+		}
+
+		// Default to the last certificate if we couldn't find one.
+		self.list.last().cloned()
+	}
+}
+
+pub struct NoCertificateVerification {}
+
+impl rustls::client::ServerCertVerifier for NoCertificateVerification {
+	fn verify_server_cert(
+		&self,
+		_end_entity: &rustls::Certificate,
+		_intermediates: &[rustls::Certificate],
+		_server_name: &rustls::ServerName,
+		_scts: &mut dyn Iterator<Item = &[u8]>,
+		_ocsp_response: &[u8],
+		_now: time::SystemTime,
+	) -> Result<rustls::client::ServerCertVerified, rustls::Error> {
+		Ok(rustls::client::ServerCertVerified::assertion())
+	}
+}

moq-relay/src/web.rs

@@ -0,0 +1,44 @@
+use std::sync::Arc;
+
+use axum::{extract::State, http::Method, response::IntoResponse, routing::get, Router};
+use axum_server::{tls_rustls::RustlsAcceptor, Server};
+use tower_http::cors::{Any, CorsLayer};
+
+use crate::{Config, Tls};
+
+// Run a HTTP server using Axum
+// TODO remove this when Chrome adds support for self-signed certificates using WebTransport
+pub struct Web {
+	app: Router,
+	server: Server<RustlsAcceptor>,
+}
+
+impl Web {
+	pub fn new(config: Config, tls: Tls) -> Self {
+		// Get the first certificate's fingerprint.
+		// TODO serve all of them so we can support multiple signature algorithms.
+		let fingerprint = tls.fingerprints.first().expect("missing certificate").clone();
+
+		let mut tls_config = tls.server.clone();
+		tls_config.alpn_protocols = vec![b"h2".to_vec(), b"http/1.1".to_vec()];
+		let tls_config = axum_server::tls_rustls::RustlsConfig::from_config(Arc::new(tls_config));
+
+		let app = Router::new()
+			.route("/fingerprint", get(serve_fingerprint))
+			.layer(CorsLayer::new().allow_origin(Any).allow_methods([Method::GET]))
+			.with_state(fingerprint);
+
+		let server = axum_server::bind_rustls(config.listen, tls_config);
+
+		Self { app, server }
+	}
+
+	pub async fn serve(self) -> anyhow::Result<()> {
+		self.server.serve(self.app.into_make_service()).await?;
+		Ok(())
+	}
+}
+
+async fn serve_fingerprint(State(fingerprint): State<String>) -> impl IntoResponse {
+	fingerprint
+}

moq-transport-quinn/Cargo.toml

@@ -1,26 +0,0 @@
-[package]
-name = "moq-transport-quinn"
-description = "Media over QUIC"
-authors = ["Luke Curley"]
-repository = "https://github.com/kixelated/moq-rs"
-license = "MIT OR Apache-2.0"
-
-version = "0.1.0"
-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]
-moq-transport = { path = "../moq-transport" }
-
-quinn = "0.10"
-http = "0.2"
-webtransport-quinn = "0.4.2"
-tokio = { version = "1.27", features = ["macros", "io-util"] }
-bytes = "1"
-log = "0.4"
-anyhow = "1.0.70"
-thiserror = "1.0.21"

moq-transport-quinn/src/control.rs

@@ -1,96 +0,0 @@
-use anyhow::Context;
-use moq_transport::{Decode, DecodeError, Encode, Message};
-
-use bytes::{Buf, BufMut, BytesMut};
-
-use std::io::Cursor;
-use std::sync::Arc;
-use tokio::sync::Mutex;
-
-use webtransport_quinn::{RecvStream, SendStream};
-
-pub struct SendControl {
-	stream: SendStream,
-	buf: BytesMut, // reuse a buffer to encode messages.
-}
-
-impl SendControl {
-	pub fn new(stream: SendStream) -> Self {
-		Self {
-			buf: BytesMut::new(),
-			stream,
-		}
-	}
-
-	pub async fn send<T: Into<Message>>(&mut self, msg: T) -> anyhow::Result<()> {
-		let msg = msg.into();
-		log::info!("sending message: {:?}", msg);
-
-		self.buf.clear();
-		msg.encode(&mut self.buf)?;
-
-		// TODO make this work with select!
-		self.stream.write_all(&self.buf).await?;
-
-		Ok(())
-	}
-
-	// Helper that lets multiple threads send control messages.
-	pub fn share(self) -> ControlShared {
-		ControlShared {
-			stream: Arc::new(Mutex::new(self)),
-		}
-	}
-}
-
-// Helper that allows multiple threads to send control messages.
-// There's no equivalent for receiving since only one thread should be receiving at a time.
-#[derive(Clone)]
-pub struct ControlShared {
-	stream: Arc<Mutex<SendControl>>,
-}
-
-impl ControlShared {
-	pub async fn send<T: Into<Message>>(&mut self, msg: T) -> anyhow::Result<()> {
-		let mut stream = self.stream.lock().await;
-		stream.send(msg).await
-	}
-}
-
-pub struct RecvControl {
-	stream: RecvStream,
-	buf: BytesMut, // data we've read but haven't fully decoded yet
-}
-
-impl RecvControl {
-	pub fn new(stream: RecvStream) -> Self {
-		Self {
-			buf: BytesMut::new(),
-			stream,
-		}
-	}
-
-	// Read the next full message from the stream.
-	pub async fn recv(&mut self) -> anyhow::Result<Message> {
-		loop {
-			// Read the contents of the buffer
-			let mut peek = Cursor::new(&self.buf);
-
-			match Message::decode(&mut peek) {
-				Ok(msg) => {
-					// We've successfully decoded a message, so we can advance the buffer.
-					self.buf.advance(peek.position() as usize);
-
-					log::info!("received message: {:?}", msg);
-					return Ok(msg);
-				}
-				Err(DecodeError::UnexpectedEnd) => {
-					// The decode failed, so we need to append more data.
-					let chunk = self.stream.read_chunk(1024, true).await?.context("stream closed")?;
-					self.buf.put(chunk.bytes);
-				}
-				Err(e) => return Err(e.into()),
-			}
-		}
-	}
-}

moq-transport-quinn/src/lib.rs

@@ -1,9 +0,0 @@
-mod control;
-mod object;
-mod session;
-mod stream;
-
-pub use control::*;
-pub use object::*;
-pub use session::*;
-pub use stream::*;

moq-transport-quinn/src/object.rs

@@ -1,147 +0,0 @@
-use std::{collections::BinaryHeap, io::Cursor, sync::Arc};
-
-use anyhow::Context;
-use bytes::BytesMut;
-use moq_transport::{Decode, DecodeError, Encode, Object};
-
-use tokio::io::AsyncWriteExt;
-use tokio::task::JoinSet;
-use tokio::{io::AsyncBufReadExt, sync::Mutex};
-use webtransport_quinn::Session;
-
-use crate::{RecvStream, SendStream, SendStreamOrder};
-
-// Allow this to be cloned so we can have multiple senders.
-#[derive(Clone)]
-pub struct SendObjects {
-	// This is a tokio mutex since we need to lock across await boundaries.
-	inner: Arc<Mutex<SendObjectsInner>>,
-}
-
-impl SendObjects {
-	pub fn new(session: Session) -> Self {
-		let inner = SendObjectsInner::new(session);
-		Self {
-			inner: Arc::new(Mutex::new(inner)),
-		}
-	}
-
-	pub async fn open(&mut self, header: Object) -> anyhow::Result<SendStream> {
-		let mut inner = self.inner.lock().await;
-		inner.open(header).await
-	}
-}
-
-struct SendObjectsInner {
-	session: Session,
-
-	// Quinn supports a i32 for priority, but the wire format is a u64.
-	// Our work around is to keep a list of streams in priority order and use the index as the priority.
-	// This involves more work, so TODO either increase the Quinn size or reduce the wire size.
-	ordered: BinaryHeap<SendStreamOrder>,
-	ordered_swap: BinaryHeap<SendStreamOrder>, // reuse memory to avoid allocations
-
-	// A reusable buffer for encoding headers.
-	// TODO figure out how to use BufMut on the stack and remove this.
-	buf: BytesMut,
-}
-
-impl SendObjectsInner {
-	fn new(session: Session) -> Self {
-		Self {
-			session,
-			ordered: BinaryHeap::new(),
-			ordered_swap: BinaryHeap::new(),
-			buf: BytesMut::new(),
-		}
-	}
-
-	pub async fn open(&mut self, header: Object) -> anyhow::Result<SendStream> {
-		let stream = self.session.open_uni().await.context("failed to open uni stream")?;
-		let (mut stream, priority) = SendStream::with_order(stream, header.send_order.into_inner());
-
-		// Add the priority to our existing list.
-		self.ordered.push(priority);
-
-		// Loop through the list and update the priorities of any still active streams.
-		let mut index = 0;
-		while let Some(stream) = self.ordered.pop() {
-			if stream.update(index).is_ok() {
-				// Add the stream to the new list so it'll be in sorted order.
-				self.ordered_swap.push(stream);
-				index += 1;
-			}
-		}
-
-		// Swap the lists so we can reuse the memory.
-		std::mem::swap(&mut self.ordered, &mut self.ordered_swap);
-
-		// Encode and write the stream header.
-		// TODO do this in SendStream so we don't hold the lock.
-		// Otherwise,
-		self.buf.clear();
-		header.encode(&mut self.buf).unwrap();
-		stream.write_all(&self.buf).await.context("failed to write header")?;
-
-		Ok(stream)
-	}
-}
-
-// Not clone, so we don't accidentally have two listners.
-pub struct RecvObjects {
-	session: Session,
-
-	// Streams that we've accepted but haven't read the header from yet.
-	streams: JoinSet<anyhow::Result<(Object, RecvStream)>>,
-}
-
-impl RecvObjects {
-	pub fn new(session: Session) -> Self {
-		Self {
-			session,
-			streams: JoinSet::new(),
-		}
-	}
-
-	pub async fn recv(&mut self) -> anyhow::Result<(Object, RecvStream)> {
-		loop {
-			tokio::select! {
-				res = self.session.accept_uni() => {
-					let stream = res.context("failed to accept stream")?;
-					self.streams.spawn(async move { Self::read(stream).await });
-				},
-				res = self.streams.join_next(), if !self.streams.is_empty() => {
-					return res.unwrap().context("failed to run join set")?;
-				}
-			}
-		}
-	}
-
-	async fn read(stream: webtransport_quinn::RecvStream) -> anyhow::Result<(Object, RecvStream)> {
-		let mut stream = RecvStream::new(stream);
-
-		loop {
-			// Read more data into the buffer.
-			let data = stream.fill_buf().await?;
-			if data.is_empty() {
-				anyhow::bail!("stream closed before reading header");
-			}
-
-			// Use a cursor to read the buffer and remember how much we read.
-			let mut read = Cursor::new(data);
-
-			let header = match Object::decode(&mut read) {
-				Ok(header) => header,
-				Err(DecodeError::UnexpectedEnd) => continue,
-				Err(err) => return Err(err.into()),
-			};
-
-			// We parsed a full header, advance the cursor.
-			// The borrow checker requires these on separate lines.
-			let size = read.position() as usize;
-			stream.consume(size);
-
-			return Ok((header, stream));
-		}
-	}
-}

moq-transport-quinn/src/session.rs

@@ -1,98 +0,0 @@
-use anyhow::Context;
-
-use moq_transport::{Message, SetupClient, SetupServer};
-
-use super::{RecvControl, RecvObjects, SendControl, SendObjects};
-
-/// Called by a server with an established WebTransport session.
-// TODO close the session with an error code
-pub async fn accept(session: webtransport_quinn::Session, role: moq_transport::Role) -> anyhow::Result<Session> {
-	let (send, recv) = session.accept_bi().await.context("failed to accept bidi stream")?;
-
-	let mut send_control = SendControl::new(send);
-	let mut recv_control = RecvControl::new(recv);
-
-	let setup_client = match recv_control.recv().await.context("failed to read SETUP")? {
-		Message::SetupClient(setup) => setup,
-		_ => anyhow::bail!("expected CLIENT SETUP"),
-	};
-
-	setup_client
-		.versions
-		.iter()
-		.find(|version| **version == moq_transport::Version::DRAFT_00)
-		.context("no supported versions")?;
-
-	if !setup_client.role.compatible(role) {
-		anyhow::bail!("incompatible roles: {:?} {:?}", setup_client.role, role);
-	}
-
-	let setup_server = SetupServer {
-		role,
-		version: moq_transport::Version::DRAFT_00,
-	};
-
-	send_control
-		.send(moq_transport::Message::SetupServer(setup_server))
-		.await
-		.context("failed to send setup server")?;
-
-	let send_objects = SendObjects::new(session.clone());
-	let recv_objects = RecvObjects::new(session.clone());
-
-	Ok(Session {
-		send_control,
-		recv_control,
-		send_objects,
-		recv_objects,
-	})
-}
-
-/// Called by a client with an established WebTransport session.
-pub async fn connect(session: webtransport_quinn::Session, role: moq_transport::Role) -> anyhow::Result<Session> {
-	let (send, recv) = session.open_bi().await.context("failed to oen bidi stream")?;
-
-	let mut send_control = SendControl::new(send);
-	let mut recv_control = RecvControl::new(recv);
-
-	let setup_client = SetupClient {
-		role,
-		versions: vec![moq_transport::Version::DRAFT_00].into(),
-		path: "".to_string(),
-	};
-
-	send_control
-		.send(moq_transport::Message::SetupClient(setup_client))
-		.await
-		.context("failed to send SETUP CLIENT")?;
-
-	let setup_server = match recv_control.recv().await.context("failed to read SETUP")? {
-		Message::SetupServer(setup) => setup,
-		_ => anyhow::bail!("expected SERVER SETUP"),
-	};
-
-	if setup_server.version != moq_transport::Version::DRAFT_00 {
-		anyhow::bail!("unsupported version: {:?}", setup_server.version);
-	}
-
-	if !setup_server.role.compatible(role) {
-		anyhow::bail!("incompatible roles: {:?} {:?}", role, setup_server.role);
-	}
-
-	let send_objects = SendObjects::new(session.clone());
-	let recv_objects = RecvObjects::new(session.clone());
-
-	Ok(Session {
-		send_control,
-		recv_control,
-		send_objects,
-		recv_objects,
-	})
-}
-
-pub struct Session {
-	pub send_control: SendControl,
-	pub recv_control: RecvControl,
-	pub send_objects: SendObjects,
-	pub recv_objects: RecvObjects,
-}

moq-transport-quinn/src/stream.rs

@@ -1,115 +0,0 @@
-use std::{
-	io,
-	ops::{Deref, DerefMut},
-	pin::Pin,
-	sync::{Arc, Mutex, Weak},
-	task,
-};
-
-use tokio::io::{AsyncWrite, BufReader};
-
-// Ugh, so we need to wrap SendStream with a mutex because we need to be able to call set_priority on it.
-// The problem is that set_priority takes a i32, while send_order is a VarInt
-// So the solution is to maintain a priority queue of active streams and constantly update the priority with their index.
-// So the library might update the priority of the stream at any point, while the application might similtaniously write to it.
-// The only upside is that we don't expose set_priority, so the application can't screw with things.
-pub struct SendStream {
-	stream: Arc<Mutex<webtransport_quinn::SendStream>>,
-}
-
-impl SendStream {
-	// Create a new stream with the given order, returning a handle that allows us to update the priority.
-	pub(crate) fn with_order(stream: webtransport_quinn::SendStream, order: u64) -> (Self, SendStreamOrder) {
-		let stream = Arc::new(Mutex::new(stream));
-		let weak = Arc::<Mutex<webtransport_quinn::SendStream>>::downgrade(&stream);
-
-		(SendStream { stream }, SendStreamOrder { stream: weak, order })
-	}
-}
-
-pub(crate) struct SendStreamOrder {
-	// We use Weak here so we don't prevent the stream from being closed when dereferenced.
-	// update() will return an error if the stream was closed instead.
-	stream: Weak<Mutex<webtransport_quinn::SendStream>>,
-	order: u64,
-}
-
-impl SendStreamOrder {
-	pub(crate) fn update(&self, index: i32) -> Result<(), webtransport_quinn::StreamClosed> {
-		let stream = self.stream.upgrade().ok_or(webtransport_quinn::StreamClosed)?;
-		let mut stream = stream.lock().unwrap();
-		stream.set_priority(index)
-	}
-}
-
-impl PartialEq for SendStreamOrder {
-	fn eq(&self, other: &Self) -> bool {
-		self.order == other.order
-	}
-}
-
-impl Eq for SendStreamOrder {}
-
-impl PartialOrd for SendStreamOrder {
-	fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-		// We reverse the order so the lower send order is higher priority.
-		other.order.partial_cmp(&self.order)
-	}
-}
-
-impl Ord for SendStreamOrder {
-	fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-		// We reverse the order so the lower send order is higher priority.
-		other.order.cmp(&self.order)
-	}
-}
-
-// We implement AsyncWrite so we can grab the mutex on each write attempt, instead of holding it for the entire async function.
-impl AsyncWrite for SendStream {
-	fn poll_write(self: Pin<&mut Self>, cx: &mut task::Context<'_>, buf: &[u8]) -> task::Poll<io::Result<usize>> {
-		let mut stream = self.stream.lock().unwrap();
-		Pin::new(&mut *stream).poll_write(cx, buf)
-	}
-
-	fn poll_flush(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> task::Poll<io::Result<()>> {
-		let mut stream = self.stream.lock().unwrap();
-		Pin::new(&mut *stream).poll_flush(cx)
-	}
-
-	fn poll_shutdown(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> task::Poll<io::Result<()>> {
-		let mut stream = self.stream.lock().unwrap();
-		Pin::new(&mut *stream).poll_shutdown(cx)
-	}
-}
-
-// Unfortunately, we need to wrap RecvStream with a buffer since moq-transport::Coding only supports buffered reads.
-// TODO support unbuffered reads so we only read the MoQ header and then hand off the stream.
-// NOTE: We can't use AsyncRead::chain because we need to get the inner stream for stop.
-pub struct RecvStream {
-	stream: BufReader<webtransport_quinn::RecvStream>,
-}
-
-impl RecvStream {
-	pub(crate) fn new(stream: webtransport_quinn::RecvStream) -> Self {
-		let stream = BufReader::new(stream);
-		Self { stream }
-	}
-
-	pub fn stop(self, code: u32) {
-		self.stream.into_inner().stop(code).ok();
-	}
-}
-
-impl Deref for RecvStream {
-	type Target = BufReader<webtransport_quinn::RecvStream>;
-
-	fn deref(&self) -> &Self::Target {
-		&self.stream
-	}
-}
-
-impl DerefMut for RecvStream {
-	fn deref_mut(&mut self) -> &mut Self::Target {
-		&mut self.stream
-	}
-}

moq-transport/Cargo.toml

@@ -5,7 +5,7 @@ authors = ["Luke Curley"]
 repository = "https://github.com/kixelated/moq-rs"
 license = "MIT OR Apache-2.0"
 
-version = "0.1.0"
+version = "0.2.0"
 edition = "2021"
 
 keywords = ["quic", "http3", "webtransport", "media", "live"]
@@ -16,4 +16,14 @@ categories = ["multimedia", "network-programming", "web-programming"]
 
 [dependencies]
 bytes = "1"
-thiserror = "1.0.21"
+thiserror = "1"
+tokio = { version = "1", features = ["macros", "io-util", "sync"] }
+log = "0.4"
+indexmap = "2"
+
+quinn = "0.10"
+webtransport-quinn = "0.6"
+#webtransport-quinn = { path = "../../webtransport-rs/webtransport-quinn" }
+
+async-trait = "0.1"
+paste = "1"

moq-transport/README.md

@@ -0,0 +1,10 @@
+[![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)

moq-transport/src/cache/broadcast.rs

@@ -0,0 +1,262 @@
+//! 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();
+	}
+}

moq-transport/src/cache/error.rs

@@ -0,0 +1,51 @@
+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(),
+		}
+	}
+}

moq-transport/src/cache/fragment.rs

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

moq-transport/src/cache/mod.rs

@@ -0,0 +1,21 @@
+//! 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::*;

moq-transport/src/cache/segment.rs

@@ -0,0 +1,216 @@
+//! 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 }
+	}
+
+	/// Write a fragment
+	pub fn push_fragment(&mut self, fragment: fragment::Subscriber) -> Result<(), CacheError> {
+		let mut state = self.state.lock_mut();
+		state.closed.clone()?;
+		state.fragments.push(fragment);
+		Ok(())
+	}
+
+	pub fn create_fragment(&mut self, fragment: fragment::Info) -> Result<fragment::Publisher, CacheError> {
+		let (publisher, subscriber) = fragment::new(fragment);
+		self.push_fragment(subscriber)?;
+		Ok(publisher)
+	}
+
+	/// Close the segment with an error.
+	pub fn close(self, err: CacheError) -> Result<(), CacheError> {
+		self.state.lock_mut().close(err)
+	}
+}
+
+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 next_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();
+	}
+}

moq-transport/src/cache/track.rs

@@ -0,0 +1,337 @@
+//! 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 next_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 {}

moq-transport/src/cache/watch.rs

@@ -0,0 +1,180 @@
+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
+		}
+	}
+}

moq-transport/src/coding/decode.rs

@@ -1,9 +1,21 @@
-use super::VarInt;
-use bytes::{Buf, Bytes};
-use std::str;
+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")]
@@ -12,65 +24,32 @@ pub enum DecodeError {
 	#[error("invalid string")]
 	InvalidString(#[from] str::Utf8Error),
 
-	#[error("invalid type: {0:?}")]
-	InvalidType(VarInt),
+	#[error("invalid message: {0:?}")]
+	InvalidMessage(VarInt),
 
-	#[error("unknown error")]
-	Unknown,
-}
+	#[error("invalid role: {0:?}")]
+	InvalidRole(VarInt),
 
-pub trait Decode: Sized {
-	// Decodes a message, returning UnexpectedEnd if there's not enough bytes in the buffer.
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError>;
-}
+	#[error("invalid subscribe location")]
+	InvalidSubscribeLocation,
 
-impl Decode for Bytes {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let size = VarInt::decode(r)?.into_inner() as usize;
-		if r.remaining() < size {
-			return Err(DecodeError::UnexpectedEnd);
-		}
+	#[error("varint bounds exceeded")]
+	BoundsExceeded(#[from] BoundsExceeded),
 
-		let buf = r.copy_to_bytes(size);
-		Ok(buf)
-	}
-}
+	// TODO move these to ParamError
+	#[error("duplicate parameter")]
+	DupliateParameter,
 
-impl Decode for Vec<u8> {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		Bytes::decode(r).map(|b| b.to_vec())
-	}
-}
+	#[error("missing parameter")]
+	MissingParameter,
 
-impl Decode for String {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let data = Vec::decode(r)?;
-		let s = str::from_utf8(&data)?.to_string();
-		Ok(s)
-	}
-}
+	#[error("invalid parameter")]
+	InvalidParameter,
 
-impl Decode for u8 {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		if r.remaining() < 1 {
-			return Err(DecodeError::UnexpectedEnd);
-		}
+	#[error("io error: {0}")]
+	IoError(#[from] std::io::Error),
 
-		Ok(r.get_u8())
+	// Used to signal that the stream has ended.
+	#[error("no more messages")]
+	Final,
 }
-}
-
-/*
-impl<const N: usize> Decode for [u8; N] {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		if r.remaining() < N {
-			return Err(DecodeError::UnexpectedEnd);
-		}
-
-		let mut buf = [0; N];
-		r.copy_to_slice(&mut buf);
-
-		Ok(buf)
-	}
-}
-*/

moq-transport/src/coding/duration.rs

@@ -1,20 +0,0 @@
-use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
-
-use bytes::{Buf, BufMut};
-
-use std::time::Duration;
-
-impl Encode for Duration {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		let ms = self.as_millis();
-		let ms = VarInt::try_from(ms)?;
-		ms.encode(w)
-	}
-}
-
-impl Decode for Duration {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let ms = VarInt::decode(r)?;
-		Ok(Self::from_millis(ms.into()))
-	}
-}

moq-transport/src/coding/encode.rs

@@ -1,95 +1,27 @@
-use super::{BoundsExceeded, VarInt};
-use bytes::{BufMut, Bytes};
+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("unexpected end of buffer")]
-	UnexpectedEnd,
-
 	#[error("varint too large")]
 	BoundsExceeded(#[from] BoundsExceeded),
 
-	#[error("unknown error")]
-	Unknown,
-}
+	#[error("invalid value")]
+	InvalidValue,
 
-pub trait Encode: Sized {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError>;
-}
-
-impl Encode for Bytes {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.as_ref().encode(w)
-	}
-}
-
-impl Encode for Vec<u8> {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.as_slice().encode(w)
-	}
-}
-
-impl Encode for &[u8] {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		let size = VarInt::try_from(self.len())?;
-		size.encode(w)?;
-
-		if w.remaining_mut() < self.len() {
-			return Err(EncodeError::UnexpectedEnd);
-		}
-		w.put_slice(self);
-
-		Ok(())
-	}
-}
-
-impl Encode for String {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.as_bytes().encode(w)
-	}
-}
-
-impl Encode for u8 {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		if w.remaining_mut() < 1 {
-			return Err(EncodeError::UnexpectedEnd);
-		}
-
-		w.put_u8(*self);
-		Ok(())
-	}
-}
-
-impl Encode for u16 {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		if w.remaining_mut() < 2 {
-			return Err(EncodeError::UnexpectedEnd);
-		}
-
-		w.put_u16(*self);
-		Ok(())
-	}
-}
-
-impl Encode for u32 {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		if w.remaining_mut() < 4 {
-			return Err(EncodeError::UnexpectedEnd);
-		}
-
-		w.put_u32(*self);
-		Ok(())
-	}
-}
-impl Encode for u64 {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		if w.remaining_mut() < 8 {
-			return Err(EncodeError::UnexpectedEnd);
-		}
-
-		w.put_u64(*self);
-		Ok(())
-	}
+	#[error("i/o error: {0}")]
+	IoError(#[from] std::io::Error),
 }

moq-transport/src/coding/mod.rs

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

moq-transport/src/coding/params.rs

@@ -0,0 +1,85 @@
+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)
+		}
+	}
+}

moq-transport/src/coding/string.rs

@@ -0,0 +1,29 @@
+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)
+	}
+}

moq-transport/src/coding/varint.rs

@@ -5,13 +5,14 @@
 use std::convert::{TryFrom, TryInto};
 use std::fmt;
 
-use crate::coding::{Decode, DecodeError, Encode, EncodeError};
-
-use bytes::{Buf, BufMut};
+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 too large for varint encoding")]
+#[error("value out of range")]
 pub struct BoundsExceeded;
 
 /// An integer less than 2^62
@@ -23,8 +24,12 @@ pub struct BoundsExceeded;
 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 {
@@ -108,6 +113,45 @@ impl TryFrom<usize> for VarInt {
 	}
 }
 
+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)
@@ -120,43 +164,36 @@ impl fmt::Display for VarInt {
 	}
 }
 
+#[async_trait::async_trait]
 impl Decode for VarInt {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let mut buf = [0; 8];
-
-		if r.remaining() < 1 {
-			return Err(DecodeError::UnexpectedEnd);
+	/// 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
+	}
 }
 
-		buf[0] = r.get_u8();
+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 tag = buf[0] >> 6;
-		buf[0] &= 0b0011_1111;
+		let mut buf = [0u8; 8];
+		buf[0] = b & 0b0011_1111;
 
 		let x = match tag {
 			0b00 => u64::from(buf[0]),
 			0b01 => {
-				if r.remaining() < 1 {
-					return Err(DecodeError::UnexpectedEnd);
-				}
-
-				r.copy_to_slice(buf[1..2].as_mut());
+				r.read_exact(buf[1..2].as_mut()).await?;
 				u64::from(u16::from_be_bytes(buf[..2].try_into().unwrap()))
 			}
 			0b10 => {
-				if r.remaining() < 3 {
-					return Err(DecodeError::UnexpectedEnd);
-				}
-
-				r.copy_to_slice(buf[1..4].as_mut());
+				r.read_exact(buf[1..4].as_mut()).await?;
 				u64::from(u32::from_be_bytes(buf[..4].try_into().unwrap()))
 			}
 			0b11 => {
-				if r.remaining() < 7 {
-					return Err(DecodeError::UnexpectedEnd);
-				}
-
-				r.copy_to_slice(buf[1..8].as_mut());
+				r.read_exact(buf[1..8].as_mut()).await?;
 				u64::from_be_bytes(buf)
 			}
 			_ => unreachable!(),
@@ -166,19 +203,30 @@ impl Decode for VarInt {
 	}
 }
 
+#[async_trait::async_trait]
 impl Encode for VarInt {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
+	/// 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) {
-			(x as u8).encode(w)
+			w.write_u8(x as u8).await?;
 		} else if x < 2u64.pow(14) {
-			(0b01 << 14 | x as u16).encode(w)
+			w.write_u16(0b01 << 14 | x as u16).await?;
 		} else if x < 2u64.pow(30) {
-			(0b10 << 30 | x as u32).encode(w)
+			w.write_u32(0b10 << 30 | x as u32).await?;
 		} else if x < 2u64.pow(62) {
-			(0b11 << 62 | x).encode(w)
+			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())
 	}
 }

moq-transport/src/control/announce.rs

@@ -1,23 +0,0 @@
-use crate::coding::{Decode, DecodeError, Encode, EncodeError};
-
-use bytes::{Buf, BufMut};
-
-#[derive(Debug)]
-pub struct Announce {
-	// The track namespace
-	pub track_namespace: String,
-}
-
-impl Decode for Announce {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let track_namespace = String::decode(r)?;
-		Ok(Self { track_namespace })
-	}
-}
-
-impl Encode for Announce {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.track_namespace.encode(w)?;
-		Ok(())
-	}
-}

moq-transport/src/control/announce_error.rs

@@ -1,40 +0,0 @@
-use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
-
-use bytes::{Buf, BufMut};
-
-#[derive(Debug)]
-pub struct AnnounceError {
-	// Echo back the namespace that was announced.
-	// TODO Propose using an ID to save bytes.
-	pub track_namespace: String,
-
-	// An error code.
-	pub code: VarInt,
-
-	// An optional, human-readable reason.
-	pub reason: String,
-}
-
-impl Decode for AnnounceError {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let track_namespace = String::decode(r)?;
-		let code = VarInt::decode(r)?;
-		let reason = String::decode(r)?;
-
-		Ok(Self {
-			track_namespace,
-			code,
-			reason,
-		})
-	}
-}
-
-impl Encode for AnnounceError {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.track_namespace.encode(w)?;
-		self.code.encode(w)?;
-		self.reason.encode(w)?;
-
-		Ok(())
-	}
-}

moq-transport/src/control/announce_ok.rs

@@ -1,23 +0,0 @@
-use crate::coding::{Decode, DecodeError, Encode, EncodeError};
-
-use bytes::{Buf, BufMut};
-
-#[derive(Debug)]
-pub struct AnnounceOk {
-	// Echo back the namespace that was announced.
-	// TODO Propose using an ID to save bytes.
-	pub track_namespace: String,
-}
-
-impl Decode for AnnounceOk {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let track_namespace = String::decode(r)?;
-		Ok(Self { track_namespace })
-	}
-}
-
-impl Encode for AnnounceOk {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.track_namespace.encode(w)
-	}
-}

moq-transport/src/control/go_away.rs

@@ -1,21 +0,0 @@
-use crate::coding::{Decode, DecodeError, Encode, EncodeError};
-
-use bytes::{Buf, BufMut};
-
-#[derive(Debug)]
-pub struct GoAway {
-	pub url: String,
-}
-
-impl Decode for GoAway {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let url = String::decode(r)?;
-		Ok(Self { url })
-	}
-}
-
-impl Encode for GoAway {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.url.encode(w)
-	}
-}

moq-transport/src/control/mod.rs

@@ -1,103 +0,0 @@
-mod announce;
-mod announce_error;
-mod announce_ok;
-mod go_away;
-mod role;
-mod setup_client;
-mod setup_server;
-mod subscribe;
-mod subscribe_error;
-mod subscribe_ok;
-mod version;
-
-pub use announce::*;
-pub use announce_error::*;
-pub use announce_ok::*;
-pub use go_away::*;
-pub use role::*;
-pub use setup_client::*;
-pub use setup_server::*;
-pub use subscribe::*;
-pub use subscribe_error::*;
-pub use subscribe_ok::*;
-pub use version::*;
-
-use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
-
-use bytes::{Buf, BufMut};
-use std::fmt;
-
-// NOTE: This is forked from moq-transport-00.
-//   1. SETUP role indicates local support ("I can subscribe"), not remote support ("server must publish")
-//   2. SETUP_SERVER is id=2 to disambiguate
-//   3. messages do not have a specified length.
-//   4. messages are sent over a single bidrectional stream (after SETUP), not unidirectional streams.
-//   5. SUBSCRIBE specifies the track_id, not SUBSCRIBE_OK
-//   6. optional parameters are written in order, and zero when unset (setup, announce, subscribe)
-
-// 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,)*} => {
-		pub enum Message {
-			$($name($name)),*
-		}
-
-
-		impl Decode for Message {
-			fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-				let t = VarInt::decode(r)?;
-
-				match t.into_inner() {
-					$($val => {
-						let msg = $name::decode(r)?;
-						Ok(Self::$name(msg))
-					})*
-					_ => Err(DecodeError::InvalidType(t)),
-				}
-			}
-		}
-
-
-		impl Encode for Message {
-			fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-				match self {
-					$(Self::$name(ref m) => {
-						VarInt::from_u32($val).encode(w)?;
-						m.encode(w)
-					},)*
-				}
-			}
-		}
-
-		$(impl From<$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
-	SetupClient = 0x1,
-	SetupServer = 0x2,
-	Subscribe = 0x3,
-	SubscribeOk = 0x4,
-	SubscribeError = 0x5,
-	Announce = 0x6,
-	AnnounceOk = 0x7,
-	AnnounceError = 0x8,
-	GoAway = 0x10,
-}

moq-transport/src/control/setup_client.rs

@@ -1,41 +0,0 @@
-use super::{Role, Versions};
-use crate::coding::{Decode, DecodeError, Encode, EncodeError};
-
-use bytes::{Buf, BufMut};
-
-// Sent by the client to setup up the session.
-#[derive(Debug)]
-pub struct SetupClient {
-	// NOTE: This is not a message type, but rather the control stream header.
-	// Proposal: https://github.com/moq-wg/moq-transport/issues/138
-
-	// The list of supported versions in preferred order.
-	pub versions: Versions,
-
-	// Indicate if the client is a publisher, a subscriber, or both.
-	// Proposal: moq-wg/moq-transport#151
-	pub role: Role,
-
-	// The path, non-empty ONLY when not using WebTransport.
-	pub path: String,
-}
-
-impl Decode for SetupClient {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let versions = Versions::decode(r)?;
-		let role = Role::decode(r)?;
-		let path = String::decode(r)?;
-
-		Ok(Self { versions, role, path })
-	}
-}
-
-impl Encode for SetupClient {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.versions.encode(w)?;
-		self.role.encode(w)?;
-		self.path.encode(w)?;
-
-		Ok(())
-	}
-}

moq-transport/src/control/setup_server.rs

@@ -1,35 +0,0 @@
-use super::{Role, Version};
-use crate::coding::{Decode, DecodeError, Encode, EncodeError};
-
-use bytes::{Buf, BufMut};
-
-// Sent by the server in response to a client.
-// 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 SetupServer {
-	// The list of supported versions in preferred order.
-	pub version: Version,
-
-	// param: 0x0: Indicate if the server is a publisher, a subscriber, or both.
-	// Proposal: moq-wg/moq-transport#151
-	pub role: Role,
-}
-
-impl Decode for SetupServer {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let version = Version::decode(r)?;
-		let role = Role::decode(r)?;
-
-		Ok(Self { version, role })
-	}
-}
-
-impl Encode for SetupServer {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.version.encode(w)?;
-		self.role.encode(w)?;
-
-		Ok(())
-	}
-}

moq-transport/src/control/subscribe.rs

@@ -1,40 +0,0 @@
-use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
-
-use bytes::{Buf, BufMut};
-
-#[derive(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 track_id: VarInt,
-
-	// The track namespace.
-	pub track_namespace: String,
-
-	// The track name.
-	pub track_name: String,
-}
-
-impl Decode for Subscribe {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let track_id = VarInt::decode(r)?;
-		let track_namespace = String::decode(r)?;
-		let track_name = String::decode(r)?;
-
-		Ok(Self {
-			track_id,
-			track_namespace,
-			track_name,
-		})
-	}
-}
-
-impl Encode for Subscribe {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.track_id.encode(w)?;
-		self.track_namespace.encode(w)?;
-		self.track_name.encode(w)?;
-
-		Ok(())
-	}
-}

moq-transport/src/control/subscribe_error.rs

@@ -1,37 +0,0 @@
-use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
-
-use bytes::{Buf, BufMut};
-
-#[derive(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 track.
-	pub track_id: VarInt,
-
-	// An error code.
-	pub code: VarInt,
-
-	// An optional, human-readable reason.
-	pub reason: String,
-}
-
-impl Decode for SubscribeError {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let track_id = VarInt::decode(r)?;
-		let code = VarInt::decode(r)?;
-		let reason = String::decode(r)?;
-
-		Ok(Self { track_id, code, reason })
-	}
-}
-
-impl Encode for SubscribeError {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.track_id.encode(w)?;
-		self.code.encode(w)?;
-		self.reason.encode(w)?;
-
-		Ok(())
-	}
-}

moq-transport/src/control/subscribe_ok.rs

@@ -1,36 +0,0 @@
-use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
-
-use std::time::Duration;
-
-use bytes::{Buf, BufMut};
-
-#[derive(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 track_id: VarInt,
-
-	// The subscription will end after this duration has elapsed.
-	// A value of zero is invalid.
-	pub expires: Option<Duration>,
-}
-
-impl Decode for SubscribeOk {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let track_id = VarInt::decode(r)?;
-		let expires = Duration::decode(r)?;
-		let expires = if expires == Duration::ZERO { None } else { Some(expires) };
-
-		Ok(Self { track_id, expires })
-	}
-}
-
-impl Encode for SubscribeOk {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.track_id.encode(w)?;
-		self.expires.unwrap_or_default().encode(w)?;
-
-		Ok(())
-	}
-}

moq-transport/src/control/version.rs

@@ -1,81 +0,0 @@
-use crate::coding::{Decode, DecodeError, Encode, EncodeError, VarInt};
-
-use bytes::{Buf, BufMut};
-
-use std::ops::Deref;
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct Version(pub VarInt);
-
-impl Version {
-	pub const DRAFT_00: Version = Version(VarInt::from_u32(0xff00));
-}
-
-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 Decode for Version {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let v = VarInt::decode(r)?;
-		Ok(Self(v))
-	}
-}
-
-impl Encode for Version {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		self.0.encode(w)
-	}
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct Versions(pub Vec<Version>);
-
-impl Decode for Versions {
-	fn decode<R: Buf>(r: &mut R) -> Result<Self, DecodeError> {
-		let count = VarInt::decode(r)?.into_inner();
-		let mut vs = Vec::new();
-
-		for _ in 0..count {
-			let v = Version::decode(r)?;
-			vs.push(v);
-		}
-
-		Ok(Self(vs))
-	}
-}
-
-impl Encode for Versions {
-	fn encode<W: BufMut>(&self, w: &mut W) -> Result<(), EncodeError> {
-		let size: VarInt = self.0.len().try_into()?;
-		size.encode(w)?;
-
-		for v in &self.0 {
-			v.encode(w)?;
-		}
-
-		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)
-	}
-}

moq-transport/src/error.rs

@@ -0,0 +1,7 @@
+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;
+}

moq-transport/src/lib.rs

@@ -1,7 +1,18 @@
+//! 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 control;
-mod object;
+mod error;
 
-pub use coding::*;
-pub use control::*;
-pub use object::*;
+pub mod cache;
+pub mod message;
+pub mod session;
+pub mod setup;
+
+pub use coding::VarInt;
+pub use error::MoqError;

moq-transport/src/message/announce.rs

@@ -0,0 +1,30 @@
+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(())
+	}
+}

moq-transport/src/message/announce_ok.rs

@@ -0,0 +1,23 @@
+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
+	}
+}

moq-transport/src/message/announce_reset.rs

@@ -0,0 +1,39 @@
+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(())
+	}
+}

moq-transport/src/message/go_away.rs

@@ -0,0 +1,21 @@
+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
+	}
+}

moq-transport/src/message/mod.rs

@@ -0,0 +1,160 @@
+//! 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,
+}

moq-transport/src/message/object.rs

@@ -0,0 +1,108 @@
+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(())
+	}
+}

moq-transport/src/message/subscribe.rs

@@ -0,0 +1,142 @@
+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(())
+	}
+}

moq-transport/src/message/subscribe_error.rs

@@ -0,0 +1,36 @@
+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(())
+	}
+}

moq-transport/src/message/subscribe_fin.rs

@@ -0,0 +1,37 @@
+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(())
+	}
+}