UA-.NETStandard/fuzzing/Opc.Ua.Network.Fuzz/FuzzableCode.ServiceCallReassembler.cs

/* ========================================================================
 * Copyright (c) 2005-2026 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
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 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
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 *
 * The above copyright notice and this permission notice shall be
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using System;
using System.IO;
using Opc.Ua.Bindings;
using Opc.Ua.Pcap.Dissection;

namespace Opc.Ua.Fuzzing
{
    public static partial class FuzzableCode
    {
        public static void AflfuzzServiceCallReassembler(Stream stream)
        {
            LibfuzzServiceCallReassembler(ReadCapped(stream));
        }

        public static void LibfuzzServiceCallReassembler(ReadOnlySpan<byte> input)
        {
            try
            {
                var reassembler = new ServiceCallReassembler();
                reassembler.LoadKeyMaterial(TestKeyMaterial);

                int offset = 0;
                for (int frameIndex = 0; offset < input.Length && frameIndex < 16; frameIndex++)
                {
                    int length = Math.Min(input.Length - offset, 8 + (input[offset] & 0x3F));
                    if (length == 0)
                    {
                        break;
                    }

                    ReadOnlySpan<byte> chunk = input.Slice(offset, length);
                    bool fromClient = (frameIndex & 1) == 0;
                    reassembler.Push(CreateCaptureFrame(chunk, fromClient));
                    offset += length;
                }

                if (input.IsEmpty)
                {
                    reassembler.Push(CreateCaptureFrame(BuildChunk(TcpMessageType.Hello, input), true));
                }

                foreach (DecodedServiceCall call in reassembler.DrainCompleted())
                {
                    _ = call.RequestBodySize;
                }
            }
            catch (Exception ex) when (IsExpected(ex))
            {
            }
        }
    }
}