Add custom sound configuration section covering TOML config files, auto-discovery, available waveforms, and validation behavior. Update flags table, project structure, dependencies, and sound design table with accurate frequencies. Add README update step to evolution checklist. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
217 lines
7.0 KiB
Markdown
217 lines
7.0 KiB
Markdown
# NetSynth
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**Turn network traffic into ambient sound.**
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NetSynth captures live network traffic (or reads pcap files), classifies packets by protocol, and synthesizes an ambient MP3 soundscape where each traffic type produces a distinct harmonic drone. A ping sounds different from HTTPS noise, which sounds different from a port scan.
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Run it, let it listen, press Ctrl+C, get an audio fingerprint of your network.
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## Quick Start
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```bash
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# Live capture on eth0 (requires root or CAP_NET_RAW)
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sudo netsynth -i eth0
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# Press Ctrl+C after a few seconds → saves netsynth-<timestamp>.mp3
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# Sonify a pcap file (no privileges needed)
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netsynth --read capture.pcap -o output.mp3
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# Filter to DNS traffic only
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sudo netsynth -i eth0 --filter "port 53" -o dns.mp3
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# Use a custom sound config
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sudo netsynth -i eth0 --config my-sounds.toml
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```
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## Installation
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### Prerequisites
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- Go 1.24+
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- C compiler (GCC or Clang) — required for MP3 encoding (CGo)
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### Build from Source
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```bash
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git clone https://codeberg.org/gurix/yoloyolo.git
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cd yoloyolo
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go build -o netsynth ./cmd/netsynth
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```
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For a smaller binary:
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```bash
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go build -ldflags="-s -w" -o netsynth ./cmd/netsynth
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```
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### Privileges
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Live packet capture requires elevated privileges on Linux:
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```bash
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# Option A: run as root
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sudo ./netsynth -i eth0
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# Option B: grant capability (preferred)
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sudo setcap cap_net_raw=eip ./netsynth
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./netsynth -i eth0
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```
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## Usage
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```
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netsynth [flags]
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```
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| Flag | Description |
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|------|-------------|
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| `-i`, `--interface` | Network interface to capture on |
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| `--read` | Read packets from a pcap file instead of live capture |
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| `-o`, `--output` | Output MP3 file path (default: `netsynth-<timestamp>.mp3`) |
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| `--filter` | BPF filter expression, tcpdump syntax (e.g. `"port 53"`) |
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| `--config` | Path to a TOML config file for custom sound mappings |
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| `--verbose` | Print per-window protocol activity to stderr |
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| `--list-interfaces` | List available network interfaces and exit |
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### Examples
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```bash
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# Capture all traffic, verbose per-window output
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sudo netsynth -i wlan0 --verbose
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# Only HTTPS traffic
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sudo netsynth -i eth0 --filter "tcp port 443" -o https.mp3
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# Sonify a Wireshark capture (output derived: capture.pcap -> capture.mp3)
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netsynth --read capture.pcap
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# Filter a pcap file to UDP only
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netsynth --read traffic.pcap --filter "udp" -o udp-only.mp3
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# Use a custom sound config
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sudo netsynth -i eth0 --config ~/my-sounds.toml
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```
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## Custom Sound Configuration
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NetSynth supports TOML config files to override the default sound mappings per traffic class. You can change the frequency and waveform for any class without affecting the others.
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### Config File Discovery
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NetSynth looks for config files in this order (first found wins):
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1. `--config <path>` flag (error if file does not exist)
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2. `./netsynth.toml` in the current working directory
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3. `~/.config/netsynth/config.toml`
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If no config is found, NetSynth starts silently with built-in defaults.
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### Config File Format
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```toml
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# Override sound settings per traffic class.
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# Only the fields you set are changed — everything else keeps its default.
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[sounds.ICMP]
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frequency = 80.0 # Hz (default: 65.0)
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waveform = "triangle" # sine, square, sawtooth, or triangle
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[sounds.HTTPS]
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frequency = 200.0
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[sounds.DNS]
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waveform = "square"
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```
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### Available Traffic Classes
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`ICMP`, `DNS`, `HTTPS`, `HTTP`, `SSH`, `SMTP`, `NTP`, `DHCP`, `OtherTCP`, `OtherUDP`, `Unknown1`, `Unknown2`, `Unknown3`, `Unknown4`
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### Available Waveforms
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| Waveform | Character |
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|----------|-----------|
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| `sine` | Pure, clean fundamental tone |
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| `square` | Hollow, buzzy (odd harmonics) |
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| `sawtooth` | Bright, rich (all harmonics) |
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| `triangle` | Soft, mellow (odd harmonics, fast rolloff) |
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All waveforms use bandlimited additive synthesis to prevent aliasing artifacts.
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### Validation
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- **Unknown keys** are rejected at startup with an error naming the bad key (catches typos like `frequncy`)
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- **Unknown class names** produce a warning but do not prevent startup
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- **Invalid waveform values** are rejected with a clear error
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## How It Works
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NetSynth processes traffic through a four-stage pipeline:
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```
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Capture -> Classify -> Aggregate -> Synthesize -> MP3
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```
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1. **Capture** — Packets are read from a live interface (via [go-pcap](https://github.com/packetcap/go-pcap)) or a pcap file. Optional BPF filtering reduces the stream to traffic of interest.
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2. **Classify** — Each packet is matched against 12 protocol rules (ICMP, DNS, HTTPS, SSH, HTTP, SMTP, NTP, DHCP, etc.). Unrecognized traffic is deterministically hash-bucketed into 4 "unknown" classes so it still produces distinct sounds.
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3. **Aggregate** — Classified packets are grouped into 500ms time windows. Each window records per-protocol packet counts that drive synthesis amplitudes.
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4. **Synthesize & Encode** — Each traffic class maps to an oscillator at a specific frequency, waveform, and stereo position. Amplitudes rise and fall via EMA smoothing based on traffic volume. All layers are mixed and encoded to MP3 via [LAME](https://github.com/sjzar/go-lame).
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### Sound Design
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| Traffic Class | Frequency | Character |
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|--------------|-----------|-----------|
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| ICMP (Ping) | 65 Hz | Deep, distinctive ping tone |
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| DNS | 110 Hz | Quick lookup sound |
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| HTTPS/TLS | 175 Hz | Steady drone (bulk traffic) |
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| HTTP | 220 Hz | Warm web traffic hum |
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| SSH | 330 Hz | Distinct interactive tone |
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| SMTP | 440 Hz | Mail delivery tone |
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| NTP | 520 Hz | Time sync pulse |
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| DHCP | 600 Hz | Network setup sound |
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| Other TCP | 700 Hz | Generic TCP hum |
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| Other UDP | 780 Hz | Generic UDP hum |
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| Unknown 1-4 | 862–1047 Hz | Dissonant, attention-grabbing |
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Sustained traffic sounds louder; quiet periods fade to silence. The result is a unique audio fingerprint of your network activity. All frequencies and waveforms can be overridden via the [config file](#custom-sound-configuration).
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## Project Structure
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```
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cmd/netsynth/ CLI entry point (Cobra)
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capture/ Packet capture, BPF validation, pcap file reading
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classify/ Protocol classification rules and types
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aggregate/ Time-window aggregation and summary output
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synth/ Oscillators, waveforms, EMA layers, stereo mixer, tone bank
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config/ TOML config loading, validation, and partial merge
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encode/ MP3 encoding via embedded LAME
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```
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## Dependencies
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| Library | Purpose |
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|---------|---------|
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| [gopacket/gopacket](https://github.com/gopacket/gopacket) | Packet decoding |
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| [packetcap/go-pcap](https://github.com/packetcap/go-pcap) | Pure Go live capture (no libpcap) |
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| [sjzar/go-lame](https://github.com/sjzar/go-lame) | MP3 encoding (embedded LAME C source) |
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| [spf13/cobra](https://github.com/spf13/cobra) | CLI framework |
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| [BurntSushi/toml](https://github.com/BurntSushi/toml) | TOML config parsing |
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No runtime dependencies beyond the compiled binary. CGo is required at build time only (for LAME).
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## Testing
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```bash
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go test ./... -v
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```
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All tests run without root privileges (capture tests use mock data and programmatically generated pcap files).
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## License
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See [LICENSE](LICENSE) for details.
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