enricobuehler
d36bec6e9d
android / android (push) Has been cancelled
apple / screenshots (push) Has been cancelled
apple / swift (push) Has been cancelled
arch / build-publish (push) Has been cancelled
audit / bun-audit (push) Failing after 13s
audit / cargo-audit (push) Has been cancelled
ci / bench (push) Has been cancelled
ci / docs-site (push) Has been cancelled
ci / rust (push) Has been cancelled
ci / web (push) Has been cancelled
deb / build-publish (push) Has been cancelled
deb / build-publish-host (push) Has been cancelled
decky / build-publish (push) Has been cancelled
docker / build-push (ci, ci/rust-ci.Dockerfile, punktfunk-rust-ci) (push) Has been cancelled
docker / build-push (docs-site, docs-site/Dockerfile, punktfunk-docs) (push) Has been cancelled
docker / deploy-docs (push) Has been cancelled
docker / build-push (--build-arg FEDORA_VERSION=44, ci, ci/fedora-rpm.Dockerfile, punktfunk-fedora44-rpm) (push) Has been cancelled
docker / build-push (ci, ci/fedora-rpm.Dockerfile, punktfunk-fedora-rpm) (push) Has been cancelled
docker / build-push (ci, ci/rust-ci-noble.Dockerfile, punktfunk-rust-ci-noble) (push) Has been cancelled
docker / build-push (., web/Dockerfile, punktfunk-web) (push) Has been cancelled
flatpak / build-publish (push) Has been cancelled
release / apple (push) Successful in 10m1s
windows-host / package (push) Successful in 11m20s
windows-msix / package (arm64, C:\Users\Public\ffmpeg-arm64, --no-default-features, aarch64-pc-windows-msvc, C:\t-a64) (push) Successful in 3m29s
windows-msix / package (x64, C:\Users\Public\ffmpeg, , x86_64-pc-windows-msvc, C:\t) (push) Successful in 4m14s
rpm / build-publish (44, fedora-44, punktfunk-fedora44-rpm) (push) Successful in 22m16s
rpm / build-publish (43, bazzite, punktfunk-fedora-rpm) (push) Successful in 22m27s
windows / build (aarch64-pc-windows-msvc) (push) Successful in 5m28s
windows / build (x86_64-pc-windows-msvc) (push) Successful in 6m39s
Lifts the ~100 Mbps decrypt ceiling on clients without hardware AES — the armv7 soft-AES targets (webOS TVs), where AES-128-GCM resolves to fixsliced software AES + software GHASH (~50-100 cpb) while ChaCha20-Poly1305's ARX construction runs ~10-17 cpb portable, a 4-7x lift that PyroWave-on-TV needs (design/chacha20-session-cipher.md). Phase 1 (core crypto, no wire change): SessionKey merges cipher choice and key material (invalid combinations unrepresentable, zeroize + redacted-Debug discipline kept); SessionCrypto dispatches both aead-0.5 ciphers per call — the salt||seq nonce scheme, per-direction salts, seq-as-AAD and replay window carry over verbatim (same 96-bit nonce / 16-byte tag, const-asserted). Config.key becomes SessionKey; validate's zero-key rejection follows the active variant. The C ABI keeps its fixed 16-byte key mapped to AES — no ABI_VERSION bump. Phase 2 (negotiation): VIDEO_CAP_CHACHA20 (0x40) — support-plus-request in one bit, the VIDEO_CAP_444 precedent. Welcome grows cipher@68 + key_chacha@69..101, emitted only when non-zero so an AES session's Welcome stays byte-identical to the pre-cipher form; decode is fail-closed (short key or unknown id -> Err, never a silent AES fallback). No WIRE_VERSION bump; downgrade resistance inherited from the pinned-TLS control channel. Phase 3 (host): grant only when the client advertised the bit and the PUNKTFUNK_CHACHA20 kill-switch (default on, documented) allows; fresh 32-byte per-session key from the same RNG discipline, legacy key field stays independently random; resolved cipher logged at session start. Verification: seal/open suites parameterized over both ciphers + a cross-cipher tamper case; Welcome roundtrip/truncation/fail-closed tests; ChaCha lossy-loopback soak (loss/replay is cipher-independent); bench gains _chacha20 series (AES ids unchanged for CI history) — host-side sealing line-rate-trivial on both x86 (~640 MiB/s) and Apple Silicon (~535 MiB/s). punktfunk-probe drives the interop matrix via PUNKTFUNK_CLIENT_CHACHA20=1 and logs the negotiated cipher. Phase 4 (pf-webos pin bump + unconditional cap bit) follows the next core release. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
punktfunk-core
The shared protocol core — the one place where punktfunk's transport, forward error correction, and crypto live. It's linked into the host and every native client, so there's exactly one implementation of the wire format everywhere.
Written in Rust with no async on the per-frame path (native threads only). It exposes both a normal Rust API and a stable, versioned C ABI, so the Swift and Kotlin clients — and any C embedder — link the same code as the Rust ones.
What's in here
- Transport & session (
session.rs,transport/,packet.rs) — thepunktfunk/1data plane over raw UDP: packetization, reassembly (with attacker-bounded limits), pacing, and socket tuning. - FEC (
fec/) — the wall-breaker. Two codes:- GF(2⁸) classic Reed–Solomon with the Cauchy generator matrix — byte-identical to the
nanorslibrary Moonlight uses, so our parity is decodable by a stock Moonlight client. - GF(2¹⁶) Leopard-RS (SIMD, O(n log n)) — up to 65535 shards/block, which removes the ~1 Gbps
FEC ceiling.
punktfunk/1negotiates this one.
- GF(2⁸) classic Reed–Solomon with the Cauchy generator matrix — byte-identical to the
- Crypto (
crypto.rs) — AES-128-GCM session encryption with per-direction nonce salts and sequence-as-AAD; SPAKE2 PIN pairing lives behind thequicfeature. - QUIC control plane (
quic.rs,client.rs, featurequic) — the Hello/Welcome/Start handshake, cert pinning/TOFU, reverse audio, and the embeddableNativeClientconnector. This is the only placetokio/quinnare allowed; the feature is off by default so the core stays runtime-free. - C ABI (
abi.rs) — the versioned surface (punktfunk_abi_version(),PunktfunkConfigcarrying its ownstruct_size) that generatesinclude/punktfunk_core.hvia cbindgen at build time.
Build outputs
The crate builds three ways at once (crate-type = ["lib", "cdylib", "staticlib"]):
| Output | Used by |
|---|---|
lib (rlib) |
the host, probe, and tools link it as a normal Rust crate |
cdylib (.so/.dylib) |
the Swift / Kotlin clients via the C ABI |
staticlib (.a) |
the C test harness and static embedding |
Test
cargo test -p punktfunk-core # unit + proptest + loopback
cargo run -p loss-harness # FEC loss-resilience sweep (no network needed)
bash crates/punktfunk-core/tests/c/run.sh # standalone C-ABI link + round-trip proof
Design invariants (do not regress)
- One core, linked everywhere — protocol/FEC/crypto live only here, behind the stable C ABI.
- No async on the hot path — the per-frame pipeline is native threads only;
quic(tokio/quinn) is control-plane only, feature-gated, off by default. - Security hardening stays intact — the reassembler bounds attacker-controlled fields before
allocating; AES-GCM keeps per-direction nonce salts + seq-as-AAD; the ABI checks
struct_size. Regression tests exist — keep them green.
Related
punktfunk-host— the streaming host built on this core- Clients — the apps that link this core over the C ABI (or directly, in Rust)
- punktfunk-planning:
implementation-plan.md(internal planning repo) — why GF(2¹⁶) FEC, the latency budget, and the architecture thesis