enricobuehler
7b2cdf5a7a
Four defects from the punktfunk-core quality sweep, all in the data plane. transport/udp: the hole-punch adopted the source address of ANY datagram whose first 8 bytes matched PUNCH_MAGIC — a fixed public constant with no key, nonce or session id — and the authenticated QUIC peer was passed only as the no-punch fallback, so it was never used to validate. Hole-punch is the default bring-up path (it is skipped only for a fixed --data-port), and the data socket is an OS ephemeral, so spraying the ephemeral range during the 2500 ms punch wait let anyone steal the video plane: the legitimate client is then filtered out by the connect() and gets nothing, while QUIC stays healthy so no reconnect fires. With a spoofed source the same 8 bytes aim a full-rate stream at a third party. Take the authenticated peer IP and require the punch to match it — only the PORT is in question (that is what a NAT remaps and what the punch exists to discover); the client dials the same host IP as its QUIC connection, so a NAT presents one source IP for both planes. Also budget each read from the REMAINING window, so off-peer datagrams cannot stretch the wait past punch_timeout. transport/udp: the punch keepalive treated every send error as fatal and broke out of its loop permanently and silently. It holds a clone of the connected, non-blocking data socket — exactly the socket whose transient conditions this module defines and documents in is_transient_io. One ENOBUFS from a full wlan tx queue or an ENETUNREACH during an AP roam killed the only thing holding the NAT mapping open; the path recovers, video keeps flowing, and the stream dies later when the idle timer expires the mapping during a static scene. Route it through is_transient_io like every other send site in the file. packet: adaptive FEC moved fec_percent live (host bands it 1..=50 while Welcome advertises 10) but the receiver's per-block acceptance ceiling was computed once from the negotiated percentage and never re-derived. Once FEC ramped, every packet of a maximal block failed `total > max_total_shards`, the block never accumulated a shard, the frame aged out, and the resulting loss drove FEC higher still — large frames wedged at 100% loss exactly when FEC was meant to rescue the link. Fixed on both sides, because hosts and clients update independently: the sender clamps per-block parity to the ceiling the peer negotiated, and the receiver sizes that ceiling from the whole clamp range rather than a stale snapshot of it. No wire bytes and no C ABI signature change; WIRE_VERSION and ABI_VERSION are unchanged. Regression tests cover all three (the punch tests were confirmed to fail without the fix). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
punktfunk-host
The streaming host — the program you run on the machine whose desktop or games you want to stream. For each client that connects, it spins up a virtual display sized to that device, captures it on the GPU, encodes with hardware NVENC/VAAPI/AMF/QSV, and sends it out over a low-latency transport — no physical monitor, no letterboxing, no rearranging your real screens.
It speaks two protocols from one process:
- GameStream — so any Moonlight / Artemis client works day one.
punktfunk/1— punktfunk's own faster protocol (QUIC control plane, GF(2¹⁶) FEC + AES-GCM data plane) that the native clients use.
Runs on Linux (the primary, most battle-tested path) and Windows (x64). The shared protocol,
FEC, and crypto live in punktfunk-core; this crate is everything
platform-facing around it.
What it does
- Per-client virtual displays at the exact WxH@Hz. Linux uses per-compositor backends — KWin, gamescope, Mutter, and Sway/wlroots; Windows uses its own all-Rust IddCx virtual display, even on the secure desktop (UAC / lock screen).
- GPU zero-copy capture → encode. dmabuf → CUDA/Vulkan → NVENC on Linux; on Windows the host pushes frames straight into its own IDD (sealed IDD-push, no screen-scraping) → GPU encode. Encoders auto-select by GPU vendor: NVENC (NVIDIA), VAAPI (Linux AMD/Intel), AMF/QSV (Windows AMD/Intel), or software H.264 as a floor. HDR/10-bit and HEVC 4:4:4 supported.
- Input injection. Mouse/keyboard (libei / gamescope EIS / wlr / Windows SendInput) and virtual gamepads — Xbox 360/One, DualSense, DualShock 4 — with rumble and HID feedback back-channels.
- Audio both ways. Opus audio host→client, plus a virtual microphone the client can talk into.
- Trust & discovery. A persistent host identity, SPAKE2 PIN pairing (default) or TOFU, and mDNS auto-advertisement so clients find the host without typing an IP.
- Management API + web console. A REST API (
mgmt.rs, OpenAPI atapi/openapi.json) drives status, paired devices, and on-demand pairing; the browser UI is inweb/.
Run it
punktfunk-host serve runs inside your desktop session. Bare serve is the secure native-only
default (punktfunk/1 + the management API); add --gamestream on a trusted LAN to also accept
stock Moonlight clients.
# Linux, from the repo root (see the repo README "Running on this box" for the headless recipe):
cargo run -rp punktfunk-host -- serve # native-only (secure default)
cargo run -rp punktfunk-host -- serve --gamestream # + Moonlight compatibility
Then pair from the web console (https://<host-ip>:47992) or the client app.
Most people should install a package rather than run from source — see
packaging/ (apt · rpm/COPR/bootc · Arch/sysext · Windows installer) and
the per-platform guides at docs.punktfunk.unom.io/docs/install.
Subcommands
| Command | Purpose |
|---|---|
serve |
The host (native punktfunk/1 + mgmt API; --gamestream adds Moonlight). |
punktfunk1-host |
Standalone native-protocol listener for testing/measurement (--source virtual, --max-sessions). |
openapi |
Print the management-API OpenAPI spec (regenerates api/openapi.json). |
library |
Inspect the multi-store game library. |
service · driver · web |
Windows: SCM service, driver install, bundled web console. |
*-test / *-selftest / *-probe |
Diagnostics (input, zero-copy, HDR, compositor, gamepads). |
--help lists them all.
Layout
src/
main.rs CLI + subcommand dispatch
config.rs · session_plan.rs · session_tuning.rs · pipeline.rs session setup + the frame pipeline
vdisplay/ per-compositor virtual outputs (kwin · gamescope · mutter · wlroots)
capture/ · capture.rs screen/dmabuf capture (+ Windows IDD-push)
encode/ · encode.rs per-GPU encoders (nvenc · vaapi · ffmpeg_win (AMF/QSV) · sw)
linux/zerocopy/ dmabuf → CUDA → NVENC bridges (EGL/GL tiled, Vulkan LINEAR)
inject/ · inject.rs input backends (libei · wlr · uinput gamepads · UHID DualSense/DS4)
audio/ · audio.rs Opus out + virtual mic (PipeWire / WASAPI)
gamestream/ Moonlight compat: nvhttp · pairing · rtsp · control · stream · gamepad · apps
native.rs the native punktfunk/1 host (QUIC control + native-thread UDP data plane)
mgmt.rs · native_pairing.rs · stats_recorder.rs management API, pairing, perf capture
hdr.rs · library.rs HDR metadata; multi-store game library
linux/ · windows/ platform-confined backends
Related
punktfunk-core— the shared protocol · FEC · crypto core- Clients — the apps that connect (Apple · Linux · Windows · Android · probe)
- Packaging & docs — install & operate
- punktfunk-planning (internal planning repo) — architecture rationale and deep-dive plans