Pure stdlib. Implements the spec's core: enrollment (single-use tokens), profile (SPKI pin, only real capabilities advertised), sessions with the §2.4 HKDF-SHA256 key schedule; UDP data plane with the 32-byte ELT1 header, 4-byte HMAC gate, 1024-wide anti-replay window, ECHO_RESP with observation block, TIMESYNC, and the §3.4 anti-amplification cap. Wire format has tests (roundtrip + silent-drop cases); enroll→profile→session smoke-tested live. Modes: container (autodetect /.dockerenv|/run/.containerenv|cgroup, or --docker/ECHOLOT_DOCKER=1; config via ECHOLOT_* env; distroless image; network_mode host required — Docker NAT would falsify observed sources) and native (--install-systemd/--uninstall-systemd with a hardened unit, opt-in --self-update from Gitea releases; refused in containers). CI: tests on any server/ push; server-v* tags build+push the image to the Gitea registry and attach linux amd64/arm64 binaries + SHA256SUMS to a release — the artifact self-update consumes. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Echolot
Free software for detecting and debugging local network issues from an Android phone — built for people who actually know what a neighbor table is.
Most "wifi analyzer" apps show you signal bars. Echolot aims at the layer where home and office networks actually break: duplicate DHCP servers, broken IPv6 RAs, MTU black holes, NAT64 weirdness, multicast that dies at the AP, DNS that answers differently than it should. It records what it observed, separates observation from interpretation, and exports the whole run so you can argue with it later.
Status: pre-release. The capability prober runs on real hardware; the production app and the probe server are not built yet.
Repository layout
docs/ design docs — the contract for everything below
echolot-prober/ capability prober: validates the no-root feasibility matrix on real devices
The Go probe server and the production app land here as siblings.
Design docs
The three specs are draft-complete and reviewed; treat them as the contract.
| Doc | What it defines |
|---|---|
| docs/feature-catalog-and-feasibility.md | Full feature list + the no-root feasibility matrix |
| docs/measurement-schema.md | Archived/exportable measurement JSON (observation vs finding, two-clock rule, anonymization) |
| docs/probe-protocol.md | Client↔server wire protocol (pinned TLS control plane, binary UDP data plane, STUN, canary DNS) |
| docs/build-status.md | Running log of decisions and next steps |
Privilege tiers
Every result records which tier produced it:
app— no root, no special setup. The bulk of the functionality.shizuku— ADB-shell privileges via wireless pairing, no root. Shipped in v1.root— future optional module.
Licensing
| Part | License | Why |
|---|---|---|
| All code (app, prober, server) | GPL-3.0-or-later | The value here is the platform-API research; copyleft keeps derivative apps free |
docs/ (the specs) |
CC-BY-4.0 | A wire protocol and a measurement format should be implementable by anyone, without license anxiety |
Full texts: LICENSE (GPLv3) and docs/LICENSE (CC BY 4.0).
Sources carry SPDX-License-Identifier headers.
If you want to build a compatible server or client, the protocol and schema docs are deliberately permissive — go ahead.
Building
See echolot-prober/README.md. Short version, from echolot-prober/:
echo "sdk.dir=/path/to/Android/sdk" > local.properties
./gradlew :app:assembleDebug