# components/dante

Clean-room Dante protocol support for the ESP32-P4, written independently
from the behavioural notes in [`docs/dante-protocol-notes.md`](../../docs/dante-protocol-notes.md).

> **Licensing:** this component is Apache-2.0 and must stay clean-room. It is
> implemented from *understanding* of Dante's on-the-wire behaviour, never by
> copying, translating, or closely paraphrasing `reference/inferno` (GPL/
> AGPL). See the hard rule in [`CLAUDE.md`](../../CLAUDE.md).

## What's here now

### Discovery (`dante_discovery.h`)

Read-only mDNS/DNS-SD browsing for Dante devices. It queries the four Dante
service types (`_netaudio-arc`, `_netaudio-cmc`, `_netaudio-chan`,
`_netaudio-bund`) and reports each instance found — hostname, IP, port, and
TXT records — via a callback, or logs them if no callback is given.

- `dante_discovery_scan()` — one-shot synchronous sweep.
- `dante_discovery_start()` / `dante_discovery_stop()` — background scanner
  that repeats on an interval.

This does **not** advertise this device and does **not** touch audio, so it is
safe to run on a live Dante network. It's primarily a bring-up aid: it shows
what Dante gear is present and how its channels are formatted (sample rate,
bit depth, latency, fpp), which is exactly what you need when getting AES67
interop working.

It shares the process-wide ESP-IDF mDNS instance with the AES67 stack (it only
ever queries; it never frees mDNS).

### Advertisement (`dante_advertise.h`, `dante_device.h`)

Publishes this device over mDNS so Dante Controller / peers can see it:
`_netaudio-arc` (control endpoint) and `_netaudio-cmc` (announce endpoint) at
the device level, plus `_netaudio-chan` per transmit channel. Driven by a
`dante_identity_t` (hostname, 8-byte device id, ports, manufacturer/model,
audio format), which `dante_identity_init_default()` fills from the board's
MAC + IP.

- `dante_advertise_start(id)` / `dante_advertise_stop()`
- `dante_advertise_tx_channel(index, name)`

**Gated OFF by default** (`DANTE_ADVERTISE_ON_BOOT`). Advertising a device that
can't answer ARC/CMC makes it show up *broken* in Dante Controller, so only
turn it on once the responders below exist. TXT version strings mimic
real-hardware values and are prototype/untested — verify against a capture.

### CMC responder (`dante_cmc.h`)

Answers the "request device advertisement" message on UDP 8800: a peer that
found us via mDNS sends it to resolve our full identity, and we reply with the
process id, 8-byte factory device id, IP, and info-request port. Uses the
10-byte big-endian ARC-style request/response header (echo start_code/seqnum/
opcode1, set opcode2 = 1, opcode1 `0x1001`).

- `dante_cmc_start(id)` / `dante_cmc_stop()` — runs a small UDP listener task.

**Gated OFF by default** (`DANTE_CMC_ON_BOOT`). Still incomplete without ARC.
PROTOTYPE / untested against hardware — verify against a capture.

#### Enabling

Controlled by Kconfig (`idf.py menuconfig` → *Dante*):

- `DANTE_DISCOVERY_ON_BOOT` (default y) — `main` starts the background scanner
  once the network is up.
- `DANTE_DISCOVERY_INTERVAL_MS` (default 15000) — sweep interval.

## Not yet implemented

Everything past discovery + advertisement + CMC, in rough dependency order
(see the protocol notes):

- **ARC** server — capability + channel enumeration and the name-based
  subscription (routing) model (port 4440).
- **Flow control (dbcp)** — open/update/stop audio flows with keepalives
  (port 4455).
- **Media framing** — the 9-byte-header Dante media packets ↔ our I2S engine.
- **PTPv1** — the legacy Dante clock (see `CLAUDE.md` "Known hard problems").

## Status

Compiles as an ESP-IDF component but is **not yet build-verified** (no
ESP-IDF toolchain in the dev environment where it was written) and untested
against real Dante hardware.