The live throughput test found it: a 3-second run delivered 104 packets and stopped after 50 milliseconds. The rate check exempted the first 50 ms entirely, meaning to be lenient at startup. The effect was the opposite. A sender could dump an unbounded burst into that free window, and the instant the check switched on it compared those bytes against 50 ms worth of allowance and refused everything until real time caught up. Every short test passed — downtrain sends 50 packets, big_send seven — and every sustained send died about fifty milliseconds in. A token bucket (allowance = burst + rate x elapsed) has no such cliff; it is smooth from t=0. The burst is 100 ms of the allowed rate, floored at one ordinary datagram so a single packet is never refused outright. The floor is deliberately one datagram: at 8 kbps a 64 KB floor would be sixty-four seconds' worth, which is precisely the instant dump the ceiling exists to prevent. The existing rate test caught that when I first tried it, and it was right. Second half of the same bug: callers treated any refusal as terminal. TryAllow now says why, so a sender can pace through a transient "too fast just now" and still stop dead on a spent budget or an expired grant. Co-Authored-By: Claude Fable 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