ech-server

This repository is a small local ECH testbed for rustls 0.24.

Main reference:

• rustls PR #2993

The goal is to verify that server-side ECH works locally and that the surrounding stack still fits together:

• rustls with ECH enabled
• a simple HTTP/2 server path
• a QUIC + HTTP/3 server path
• a reqwest client using the HTTP/3 path

ECH is protocol-agnostic, so this repo uses the same TLS/ECH setup across both H2 and H3. The H3 path is the heavier integration path, while H2 is a simpler comparison path.

• server-h2: hyper + tokio-rustls + rustls
• server-h3: quinn + h3 + rustls
• client-h2: reqwest + h2 + rustls 0.24
• client-h3: reqwest + http3 + rustls 0.24

The repository pins the current PR #2993 head in Cargo.toml, keeps a locally patched reqwest under vendor/reqwest, and uses cargo vendor for reproducible local builds.

This setup expects local test assets under testdata/:

• local-ca.pem
• localhost-cert.pem
• localhost-key.pem
• default-ech-config.hex
• default-ech-config-list.hex
• default-ech-private-key.hex

If testdata/ is empty or gitignored in your checkout, generate the assets first.

Generate a local CA and localhost certificate:

cargo run --bin gen_test_certs

Generate ECH config material:

cargo run --bin gen_ech_assets

The current ECH generator uses:

• config_id = 0x42
• public_name = "localhost"
• maximum_name_length = 64

Start the HTTP/3 server:

cargo run --bin server-h3

Then run the HTTP/3 client in another terminal:

cargo run --bin client-h3

Expected output:

status: 200 OK
hello over h3: GET /hello

You can also start the HTTP/2 server:

cargo run --bin server-h2

And test it with the HTTP/2 client:

cargo run --bin client-h2

You can also do a simple transport smoke test with curl:

curl --http2 -k https://localhost:4434/hello

The reqwest clients use real ECH mode, not grease mode.

If the H3 client request succeeds and the server handles the request with ECH enabled on both sides, that is a strong indication that the ECH handshake path was accepted.

The H2 server exists as a simpler comparison path using the same TLS/ECH setup.