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 app
The production Android client (spec). Native Kotlin + Jetpack Compose. Multi-module; built bottom-up from a verifiable protocol spine.
Modules
| Module | Type | Status |
|---|---|---|
core-protocol |
pure Kotlin/JVM | done — client half of probe-protocol.md, verified live against the server |
core-measurement |
pure Kotlin/JVM | planned — measurement-schema.md types |
core-probe |
Android lib | planned — app-tier probes, ported from echolot-prober |
core-shizuku |
Android lib | planned — dual-path executor (UserService + newProcess fallback) |
app |
Android app | planned — Compose UI |
core-protocol is deliberately Android-free so it builds and unit-tests on any JDK (no Android
SDK) and can run integration tests against a live server.
core-protocol
Implements the control plane (SPKI-pinned enrollment/profile/sessions via HttpsURLConnection —
Android-API-1 compatible, hostname verification off because trust is the pin), the HKDF-SHA256
session-key schedule, and the binary ELT1 UDP data plane (HMAC gate, ECHO + observation block,
MTU probe) — byte-compatible with the Go server.
./gradlew :core-protocol:test # unit tests (crypto vectors, wire round-trip)
scripts/test-fmr.sh # live end-to-end test against the deployed server
test-fmr.sh mints an enrollment token over SSH, enrolls via the public control plane, computes
the SPKI pin from the served cert, and runs LiveServerTest — proving the client speaks the wire
protocol to the real server (enroll → profile → session → echo+observation → MTU → observations).
The live test self-skips when ECHOLOT_LIVE_* env vars are absent, so unit runs and CI stay green
offline.