mrambossekandClaude Opus 5
2ed4d1f478
A measurement tool that cannot report from a broken network is useless exactly when it matters, and a wedged resolver is one of the faults this app is built to find — it should not also be the thing that stops the finding being delivered. The profile already carries the server's addresses; they are now kept and used when the name fails. Safe because the pin is the trust and the name is not part of it: the server presents the same certificate however it was reached, and a wrong address fails the pin like anything else. Only the primaries are cached — the alternate pair exists for NAT behaviour discovery and does not carry the control plane, so falling back to one would fail for a second, unrelated reason. Substituted only when the name genuinely does not resolve, and only after checking the candidate answers on the port: on a v4-only network a v6 address would otherwise be chosen and fail slowly, which is the wrong answer delivered late. The server had to meet it halfway. Sharing 443 by SNI meant a client arriving by IP sent no server name and got the Let's Encrypt certificate, failing the pin. A numeric host — or no SNI at all — now selects the pinned certificate and routes to the control plane. That is sound because the admin UI is only ever reached by name: browsers always send SNI, and nobody bookmarks an IP for a site with a CA-issued certificate. Verified against fmr: by IP on both families the served pin is the control one and /v1/profile answers 401, while fmr.echo-lot.app still serves the Let's Encrypt certificate and the admin UI. 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