enricobuehler
9afcbcd307
Networking-audit deferred plan §4 (the qos.rs follow-up). On Windows set_tos_v4 succeeds but the stack strips the mark without a qWAVE flow, so PUNKTFUNK_DSCP=1 was a silent wire no-op there. Now (Apollo/Sunshine's approach): QOSCreateHandle once per process; QOSAddSocketToFlow per connected media socket — video → QOSTrafficTypeAudioVideo, audio → QOSTrafficTypeVoice (QOS_NON_ADAPTIVE_FLOW) — then best-effort QOSSetFlow(QOSSetOutgoingDSCPValue, 40/48) to pin the exact CS5/CS6 the other platforms mark. The pin lands for elevated processes (the host runs as the SYSTEM service — exactly where the video egress is) or under the "allow non-admin DSCP" policy; otherwise the traffic-type default marking stands (still WMM-useful). Gating + contract unchanged: opt-in via dscp_enabled(), every step debug-logs and continues. set_media_qos now returns an RAII QosFlow guard (QOSRemoveSocketFromFlow on drop) that must outlive the socket's traffic: stored in UdpTransport (declared before the socket, so drop order removes the flow first) and held for the stream's scope by the GameStream video/audio senders — whose tagging moved after connect(), since qWAVE derives the flow's 5-tuple from the connected socket (behavior-neutral on Linux). Off-Windows the guard is inert and never constructed. Validated: cargo check -p punktfunk-core --target x86_64-pc-windows-msvc green (the full host can't cross-check from Linux — aws-lc-sys needs MSVC tooling; it builds on-box via deploy-host.ps1). Remaining on the next Windows pass per plan: deploy to the RTX box and pktmon/Wireshark the client side — DSCP ≠ 0 on video egress with PUNKTFUNK_DSCP=1, 0 without. 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