# External cross-validation harnesses

Each harness in this directory validates the C++ codec, framing, and
dispatch against an **independent third-party implementation** of
the same SEMI standards.

See [`../docs/VERIFICATION.md`](../docs/VERIFICATION.md) for the
internal-vs-external breakdown across all validators.

## What's here

| Validator                                  | Independence                                | Coverage                                                                                                            |
|--------------------------------------------|---------------------------------------------|---------------------------------------------------------------------------------------------------------------------|
| `host_vs_cpp_server.py` + `passive_equipment.py` | secsgem-py 0.3.0 — Python reference impl   | 31 checks: S1, S2, S5, S6, S7, S10 happy paths + unsolicited S6F11 / S5F1                                          |
| `raw_gem300_harness.py`                    | secsgem-py with hand-crafted SecsStreamFunctions | 3 checks: S3F17, S16F5, S16F27 (limited by SFDL grammar)                                                            |
| `secs4j/Secs4jHostHarness.java`            | secs4java8 — Apache 2.0 Java impl by kenta-shimizu | **55 checks** across S1/S2/S3/S5/S6/S7/S10/S14/S16, including the full E40 body that defeated secsgem-py and unsolicited S6F11/S5F1 observation |
| `tshark_validate.sh`                       | Wireshark's built-in HSMS dissector         | 69 captured frames dissected with no malformed-packet warnings                                                       |
| `spool_persistence_test.py`                | secsgem-py + a docker-restart loop          | Restart-survives-spool integrity                                                                                     |
| ⚙️  `../tests/test_e5_kat.cpp`              | SEMI E5 §9 encoding rules                   | 196 known-answer byte assertions across every format code                                                            |
| ⚙️  `../apps/fuzz_secs2_decode.cpp` + `fuzz_sml_parse.cpp` | libFuzzer + ASan + UBSan       | ~70 000 + ~285 000 random inputs per minute, 0 crashes                                                              |

The ⚙️ entries aren't in `interop/` directly because they don't
involve a network peer — they're either pure codec round-trips
(KAT) or coverage-guided fuzzing.  Listed here so the full external
proof inventory lives in one place.

## Running each validator

### secsgem-py — secsgem-py active host → C++ server

```sh
docker compose up -d server
docker compose run --rm interop python3 /app/interop/host_vs_cpp_server.py \
    --host server --port 5000 --session-id 0
```

### secsgem-py — C++ host → secsgem-py equipment

```sh
docker compose up -d equipment_py
docker compose run --rm builder /app/build/secs_interop_probe \
    --host equipment_py --port 5000 --device 0
```

### secsgem-py — raw GEM 300 frames

```sh
docker compose up -d server
docker compose run --rm interop python3 /app/interop/raw_gem300_harness.py \
    --host server --port 5000 --session-id 0
```

### secs4j — independent Java host → C++ server

```sh
bash interop/secs4j_validate.sh
```

Builds an `eclipse-temurin:21-jdk` sidecar with secs4java8 cloned +
compiled at image build, then drives 55 checks against
`compose up server`.  See `secs4j/Secs4jHostHarness.java` for the
list and `secs4j/Dockerfile` for the build.

### tshark — Wireshark HSMS dissector

```sh
docker compose run --rm builder bash /app/interop/tshark_validate.sh
```

Captures a pcap of the demo flow, runs `tshark -V` with the HSMS
dissector forced for the test port, asserts no malformed packets +
that all expected control/data frames parse.

### spool persistence — restart-survives test

```sh
bash interop/spool_persistence_test.py
```

Drops the host link mid-flight, kills the server, restarts it, and
asserts the spooled S5F1 / S6F11 frames drain to the host on
reconnect.

## When to add a new validator

A new third-party SECS implementation, dissector, or fuzzer target
that exercises the wire surface from an angle the existing five
don't cover is worth adding.  The pattern is consistent:

1. New script / harness lives here (or a sidecar Docker context for
   non-Python validators).
2. Wired into `.gitea/workflows/ci.yml` as a separate job.
3. Listed in this README's table + in `../VERIFICATION.md`.
4. Surfaced in [`../docs/PROOFS.md`](../docs/PROOFS.md) if it adds a
   meaningful new dimension.

Bug reports from a new validator → file at `raphael@maenle.net`
with the wire trace, the validator's output, and the equipment YAML.