Files
punktfunk/clients/linux
enricobuehler 79d755cd98 feat(crypto): move the rustls backend from ring to aws-lc-rs, with PQ key exchange
The workspace pinned `ring` everywhere because aws-lc-sys 0.41.0 failed to C-compile
on the Windows CI runner. Re-tested on that runner (.133) with aws-lc-sys 0.44.0: the
`params.c` cl.exe failure does not reproduce under MSVC 14.44, and rustls's `aws_lc_rs`
feature turns on `aws-lc-rs/prebuilt-nasm`, so no NASM is needed on the box either.

That unblocks post-quantum TLS: `prefer-post-quantum` offers X25519MLKEM768 first on
every TLS 1.3 handshake (mgmt API, native control plane, QUIC), which ring cannot do —
it has no ML-KEM. Classical curves stay in the list, so older clients still connect.

rustls, quinn, rcgen and tokio-rustls each select a backend independently, so all four
had to move together; a single dissenter pulls a second crypto stack in via feature
unification. The direct `ring` users (ed25519 in pf-update-check, SHA-256 in the Windows
updater) moved to aws-lc-rs, whose API is ring-compatible.

`ring` does NOT leave the tree: ureq 2 names `features = ["ring"]` in its own rustls
dependency line and cargo features are additive, so no dependent can switch it off. Two
backends compiled in means rustls refuses to infer one, and anything built via
`ClientConfig::builder()` panics instead of picking — which is what ureq's default agent
does on its first HTTPS request. `tls::install_default_provider()` makes the choice
explicit; it runs at each binary's entry point and defensively in pf-client-core, which
several binaries link. Dropping ring entirely needs the ureq 2 -> 3 upgrade (36 call
sites), deliberately left out of this change.

Verified on macOS: pf-update-check 32, punktfunk-core 385, c_abi 1 (the last with
LIBRARY_PATH=/opt/homebrew/opt/opus/lib) — aws-lc-sys links into the C ABI harness, so
the Swift/Kotlin embedders keep working. cargo fmt --all --check clean.
2026-08-13 12:41:47 +02:00
..

punktfunk — Linux client

The native Linux app for streaming a punktfunk host to your desktop, laptop, or Steam Deck. It's a clean relm4/GTK4/libadwaita shell that finds hosts on your network, pairs with a PIN, and manages your settings and library — the stream itself runs in the sibling punktfunk-session Vulkan binary (clients/session), which the shell spawns, putting the picture on glass at your display's own resolution and refresh rate.

Built in Rust end to end (no C ABI): the shell shares its plumbing with the session binary through crates/pf-client-core, which links the punktfunk-core protocol crate and speaks the fast punktfunk/1 protocol — QUIC control plane, GF(2¹⁶) FEC + AES-GCM data plane.

Features

  • Zero-copy hardware decode, and it's ours — the session presenter decodes with Punktfunk's own decoders; no FFmpeg is linked or bundled. Vulkan Video (pf-vkdecode, decoding onto the presenter's own device) leads on NVIDIA and AMD, VAAPI (pf-vaadec driving a dlopen'd libva, exporting DRM-PRIME dmabufs) leads on Intel, whichever isn't first is the fallback, and an OpenH264/rav1d CPU rung is last.
  • Your display's native mode — the host builds a virtual output at exactly your WxH@Hz; no scaling, no letterboxing. Steady 60 fps at 1080p60, ~6 ms capture→decoded on the LAN.
  • Audio both ways — PipeWire playback with a jitter ring, plus mic uplink to the host.
  • Full controller support — SDL3 gamepads with rumble and DualSense fidelity (lightbar, player LEDs, touchpad, motion, adaptive-trigger replay). Click-to-capture keyboard and mouse, with a release chord (Ctrl+Alt+Shift+Q) and focus-loss release.
  • Find hosts automatically — mDNS discovery lists hosts on your LAN; saved hosts persist. First connect does a one-time SPAKE2 PIN pairing (or TOFU on trusted LANs), then reconnects on a pinned identity.
  • Per-host speed test to pick a bitrate, plus compositor and mode preferences in Settings.
  • Game library browser (experimental, off by default) — "Browse library…" on a saved host shows its games (Steam + custom) as a poster grid; click one to launch it in the session. Fetched from the host's management API over mTLS — paired devices are authorized by their certificate, no extra host setup.
  • Gamepad library launcher (--browse host) — a console-style, controller-driven library view of a paired host's games, rendered by the session binary's Skia console UI: A plays the focused title, B quits, L1/R1 jump. Built for the Steam Deck plugin's "Open library" launch; session end returns to the launcher. Arrow keys/Enter/Esc drive it too (no pad needed).

Get it

Most people should install a package rather than build from source:

Distro Install
Flatpak (any distro, Steam Deck) io.unom.Punktfunk — see packaging/flatpak
Ubuntu / Debian (apt) sudo apt install punktfunk-client (after adding the repo)
Fedora / Bazzite (rpm) rpm-ostree install punktfunk-client
Arch (PKGBUILD) see packaging/arch

Per-device install steps and pairing walkthrough: docs.punktfunk.unom.io/docs/install-client.

Build & run from source

Requires GTK ≥ 4.16, libadwaita ≥ 1.5, PipeWire, and SDL3 (with hidapi) development packages, plus a C compiler (the CPU rung builds OpenH264 from source). No decoder development package is needed: libva and the Vulkan loader are both opened at runtime rather than linked, so hardware decode is a fact about the box you run on — a Vulkan loader and your GPU's driver, and libva for the VAAPI rung — not about the one you build on.

# from the repo root
cargo run -p punktfunk-client-linux                 # launch the app
cargo run -p punktfunk-client-linux -- --connect HOST[:PORT]   # skip the host list and connect
cargo run -p punktfunk-client-linux -- --browse HOST           # the gamepad library launcher

The binary is named punktfunk-client — the relm4/libadwaita desktop shell (hosts, pairing/trust, settings, the desktop library page). Every stream and the console game library run in the sibling punktfunk-session Vulkan binary; the shell spawns it for connects, and --connect/--browse on the shell exec it directly (so the Decky wrapper keeps working unchanged). Headless flags stay in the shell: --pair <PIN> --connect host[:port] (pairing ceremony), --wake host[:port], and --library host[:mgmt_port] (print a host's game library).

Layout

src/
  main.rs · app.rs        entry point, relm4 AppModel (window, trust gate, session child
                          lifecycle, typed messages), primary menu, CSS
  cli.rs                  headless paths (--pair/--wake/--library), the --connect/--browse
                          exec handoff to punktfunk-session, screenshot scenes
  ui_hosts.rs             hosts page component (FactoryVecDeque cards, saved + discovered
                          grids, add-host dialog, banner)
  ui_library.rs           game-library poster grid (per-host, launches titles)
  ui_trust.rs             TOFU / PIN-pairing / request-access dialogs
  ui_settings.rs          resolution · refresh · decoder · bitrate · compositor · mic
  spawn.rs                the session-child plumbing (stdout contract → AppMsg)
tools/screenshots.sh      store screenshot capture (app self-capture; Xvfb fallback)

The UI-agnostic plumbing — session pump, the native decode ladder (Vulkan Video · VAAPI · OpenH264/rav1d), PipeWire audio, SDL3 gamepads + keymap, trust store, mDNS discovery, library client, Wake-on-LAN — lives in crates/pf-client-core, shared with the Vulkan session binary.