mrambossekandClaude Fable 5
14e5fad1b2
Three facts the client cannot produce alone, kept deliberately separate: mtu.pmtud_down (largest datagram that arrives unfragmented — meaningful only because the server sets DF), mtu.frag_delivery (whether larger ones arrive once fragmentation is allowed), and train.udp_downstream (loss, reordering and arrival spacing in the download direction, which a round trip cannot separate from upstream loss). ServerMeasurement now runs them on the same ProbeSession as the echo train. It had to: a fresh session restarts client-side sequence numbers and the server's anti-replay window discards the lot, so the re-primed source is never recorded and every granted send goes to a socket that has already closed. That produced four confidently-wrong FAILED tests and a RED verdict on a healthy network. Live against fmr: path MTU 1500, fragments to 4000, 100/100 downstream, GREEN. Co-Authored-By: Claude Fable 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.