[Rust] Add tokio-ws - WebSocket

Hand-rolled WebSocket echo server on raw tokio, with no WebSocket
library. The RFC 6455 handshake (including from-scratch SHA-1 + base64),
frame parser/masking, and echo write path are implemented directly on a
tokio TcpStream. Serving model is one current_thread runtime per core
with SO_REUSEPORT sharding, matching the other engine-tier entries.

Subscribes to echo-ws and echo-ws-pipeline. Passes validate-ws.py (7/7)
locally and via the Docker build.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: MDA2AV

frameworks/tokio-ws/.dockerignore

@@ -0,0 +1,2 @@
+target
+.git

frameworks/tokio-ws/.gitignore

@@ -0,0 +1 @@
+/target

frameworks/tokio-ws/Cargo.lock

@@ -0,0 +1,14 @@
+[package]
+name = "httparena-tokio-ws"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+socket2 = { version = "0.5", features = ["all"] }
+tokio = { version = "1", default-features = false, features = ["io-util", "net", "rt"] }
+
+[profile.release]
+codegen-units = 1
+lto = "thin"
+opt-level = 3
+panic = "abort"

frameworks/tokio-ws/Cargo.toml

@@ -0,0 +1,13 @@
+FROM rust:1.95 AS build
+WORKDIR /app
+COPY Cargo.toml Cargo.lock ./
+RUN mkdir src && echo "fn main() {}" > src/main.rs \
+    && cargo build --release \
+    && rm -rf src target/release/httparena-tokio-ws target/release/deps/httparena_tokio_ws*
+COPY src ./src
+RUN RUSTFLAGS="-C target-cpu=native" cargo build --release
+
+FROM debian:bookworm-slim
+COPY --from=build /app/target/release/httparena-tokio-ws /server
+EXPOSE 8080
+CMD ["/server"]

frameworks/tokio-ws/Dockerfile

@@ -0,0 +1,46 @@
+# tokio-ws
+
+A WebSocket echo server written directly on **raw tokio**, with the WebSocket
+protocol **hand-rolled** — no `tokio-tungstenite`, no `wtx`, no WS library at all.
+
+It exists as an `engine`-tier reference point: the lowest-level way to serve the
+`echo-ws` profile on the tokio reactor, so the leaderboard shows what the runtime
+itself can do once the framing is reduced to the minimum.
+
+## What's implemented by hand
+
+- **RFC 6455 handshake** — request parsing, `Sec-WebSocket-Accept` derivation,
+  and the `101 Switching Protocols` reply. SHA-1 and base64 are both written
+  from scratch (`src/main.rs`), so the only dependencies are `tokio` and
+  `socket2`.
+- **Frame codec** — a streaming parser that handles 7/16/64-bit lengths,
+  client→server unmasking, and partial frames split across `read()`s. Echoes are
+  re-emitted as unmasked server frames, preserving FIN + opcode (so fragmented
+  messages pass through transparently).
+- **Control frames** — `Ping` is answered with `Pong`; `Close` is echoed and the
+  connection ends.
+
+## Serving model
+
+One `current_thread` tokio runtime per core, each binding `0.0.0.0:8080` with
+`SO_REUSEPORT` so the kernel shards new connections across cores — no shared
+accept queue, no cross-core work-stealing. `TCP_NODELAY` is set per connection,
+and outgoing echoes are batched per read so a pipelined burst flushes in one
+write. This mirrors the other one-thread-per-core engine entries (e.g.
+`rust-epoll`).
+
+## Endpoint
+
+| Method | Path  | Behavior                                  |
+|--------|-------|-------------------------------------------|
+| GET    | `/ws` | WebSocket upgrade, then echo every frame  |
+
+A non-upgrade `GET /ws` is rejected with `400`; other paths return `404`.
+
+## Build & run
+
+```bash
+cargo build --release
+./target/release/httparena-tokio-ws        # listens on :8080
+python3 ../../scripts/validate-ws.py localhost 8080 /ws
+```

frameworks/tokio-ws/README.md

@@ -0,0 +1,14 @@
+{
+  "display_name": "tokio-ws",
+  "language": "Rust",
+  "type": "engine",
+  "engine": "tokio",
+  "description": "Hand-rolled WebSocket echo server on raw tokio — no WebSocket library. A current-thread runtime per core with SO_REUSEPORT sharding, a from-scratch RFC 6455 handshake (hand-written SHA-1 + base64) and a manual frame parser/masking + echo write path.",
+  "repo": "https://github.com/tokio-rs/tokio",
+  "enabled": true,
+  "tests": [
+    "echo-ws",
+    "echo-ws-pipeline"
+  ],
+  "maintainers": []
+}