OPCFoundation.NetStandard.Opc.Ua.Core.Diagnostics

OPC UA .NET Standard — Diagnostics (packet capture, dissection, replay)

OPCFoundation.NetStandard.Opc.Ua.Core.Diagnostics is an opt-in binding that captures, dissects, and replays the wire-level traffic of the OPC UA channels a host process opens — outbound client channels and/or inbound channels accepted by a hosted server. It composes with the existing opc.tcp transport as a transparent decorator — no application changes are needed beyond wiring the binding through DI (AddPcap()) or by hand (PcapBindings.Install*).

Overview

The package contains:

• PcapTransportChannelBinding — ITransportChannelFactory decorator installed via AddPcap() that wraps every TcpTransportChannel with a capture-aware byte transport (outbound client channels).
• PcapTransportListenerBinding — ITransportListenerFactory decorator that wraps a hosted server's opc.tcp listener so every accepted inbound client→server channel is capture-aware.
• ChannelCaptureRegistry + CaptureSessionManager — runtime control surface to start / stop a capture, manage rolling files, and emit pcap + keylog artifacts.
• ReplaySessionManager — offline pcap dissection and frame replay (optional, gated by PcapOptions.AllowMockClientReplay).
• Audit sinks (LoggerPcapAuditSink, HashChainedAuditFileSink) for tamper-evident capture provenance.

Getting started

using Microsoft.Extensions.DependencyInjection;
using Opc.Ua;

services.AddOpcUa();
services.AddPcap(opts =>
{
    opts.BaseFolder = "/var/log/opcua-pcap";
    opts.MaxActiveSessions = 4;
});

Without dependency injection

Install the binding by hand, then start a capture session sharing the same IChannelCaptureRegistry. Installing a binding only makes channels capture-aware; nothing is recorded until a session is running.

using Opc.Ua.Pcap.Bindings;

// server (inbound): install before the server starts its listeners
IChannelCaptureRegistry registry =
    PcapBindings.InstallServer(server.Server!.TransportBindings);

// client (outbound): install into the process-wide client default
// PcapBindings.InstallClient(ClientChannelManager.DefaultChannelBindings, registry);

See the Diagnostics guide for the full non-DI recipe (server, client, and both directions).

Target frameworks

net8.0, net9.0, net10.0.

Additional documentation

See the main repository README and the Diagnostics guide for the full design (capture-session lifecycle, key-escrow, audit chaining, replay security model).