Joseph Doherty
0a274af76f
Captured OBJREF byte structures from both paths via the .NET probe: - `--probe-callback-marshal`: DCOM-marshalled, 338 bytes, succeeds (when used inside `MxNativeSession.Open` → `CreateRegisteredService`). - `--probe-register-managed-callback`: hand-rolled, 162 bytes, fails with `RegisterEngine2 → 0x800706BA RPC_S_SERVER_UNAVAILABLE`. The structural diff: - `std_flags`: DCOM=`0x0A80` (SORF_OXRES4+6+8) vs hand-rolled=`0x280` (SORF_OXRES4+6). Bit `0x0800` (SORF_OXRES8) only set in DCOM. - ncacn_ip_tcp bindings: DCOM=4 with no ports; hand-rolled=1 with explicit `[port]`. - Total size: 338 vs 162 bytes. Tested the simplest fix (hand-rolled `std_flags = 0x0A80` to match DCOM): **still fails with the same 1722.** Reverted. **Diagnosis updated in F55:** NmxSvc on receiving RegisterEngine2 appears to call `IObjectExporter::ResolveOxid` against the local SCM (`127.0.0.1:135`) to resolve the callback OBJREF's OXID, then dial the resulting bindings. Our hand-rolled OXID is never registered with RPCSS, so the SCM-side resolution fails and NmxSvc returns RPC_S_SERVER_UNAVAILABLE — matching: - the symptom (1722), - the sub-second timing (no TCP dial-back to our listener attempted), - the fact that the .NET `ManagedCallbackExporter` (same hand-rolled approach) ALSO fails identically. DCOM marshalling fixes this because `CoMarshalInterface` internally registers the OXID with RPCSS. The bindings have no port because RPCSS returns the dynamic port from the DCOM stub layer. **Conclusion: Path A is the architecturally correct fix** — the callback exporter must be a DCOM-managed object (e.g. via `windows-rs` `#[implement]`) for NmxSvc to accept the callback. The hand-rolled-listener-with-explicit-port approach is fundamentally incompatible with NmxSvc's callback validation, in both Rust and the .NET reference. Path C (cheap investigation) is exhausted; F55 verdict updated to recommend Path A explicitly. `cargo test --workspace` 824 passing; clippy `-D warnings` clean across both feature configurations. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
mxaccess (Rust port)
Native Rust replacement for AVEVA / Wonderware MXAccess. See ../design/ for
the architectural specification, ../src/ for the .NET reference (the
executable spec), and ../CLAUDE.md for project-wide rules.
Status
M0 — Workspace skeleton. Stub types compile; nothing is implemented yet.
See ../design/60-roadmap.md for the M0–M6 milestone plan.
Layout
rust/
Cargo.toml workspace root
rust-toolchain.toml 1.85 stable
crates/
mxaccess-codec/ pure protocol codec, no I/O
mxaccess-galaxy/ Galaxy SQL resolver (tiberius)
mxaccess-rpc/ DCE/RPC + NTLMv2 + OXID + OBJREF
mxaccess-callback/ INmxSvcCallback RPC server
mxaccess-nmx/ INmxService2 client
mxaccess-asb-nettcp/ net.tcp framing (MC-NMF + MC-NBFX/NBFS)
mxaccess-asb/ IASBIDataV2 client
mxaccess/ async session + Transport trait + public API
mxaccess-compat/ LMXProxyServer-shaped facade
Build
cargo build --workspace
cargo test --workspace
cargo clippy --workspace -- -D warnings
cargo fmt --check
Live probes
. ..\tools\Setup-LiveProbeEnv.ps1
cargo test -p mxaccess --features live -- --ignored
The setup script fetches credentials from Infisical via
wwtools/secrets/Get-Secret.ps1. Never inline plaintext credentials.
License
MIT — see ../LICENSE.