}

        final int structureSize = SMBUtil.readInt2(buffer, bufferIndex);
        if (structureSize != 65) {
            throw new SMBProtocolDecodingException("Structure size is not 65, got: " + structureSize);
        }

        this.securityMode = SMBUtil.readInt2(buffer, bufferIndex + 2);
        // Validate security mode flags

        return size8(Smb2Constants.SMB2_HEADER_LENGTH + STRUCTURE_SIZE);
    }

    @Override
    protected int writeBytesWireFormat(byte[] dst, int dstIndex) {
        int start = dstIndex;

        // StructureSize (2 bytes) - must be 36
        SMBUtil.writeInt2(STRUCTURE_SIZE, dst, dstIndex);
        dstIndex += 2;

        // Reserved (2 bytes)
        SMBUtil.writeInt2(0, dst, dstIndex);
        dstIndex += 2;

    @ValueSource(ints = { 0, 1, 8, 10, 16, 18, 100, 65535 })
    void testReadBytesWireFormatInvalidStructureSize(int structureSize) {
        // Given
        byte[] buffer = new byte[256];
        int bufferIndex = 0;

        // Write invalid structure size
        SMBUtil.writeInt2(structureSize, buffer, bufferIndex);

        // When & Then
        SMBProtocolDecodingException exception =

        final int start = bufferIndex;
        final int structureSize = SMBUtil.readInt2(buffer, bufferIndex);
        if (structureSize != 9) {
            throw new SMBProtocolDecodingException("Error structureSize should be 9");
        }
        this.errorContextCount = buffer[bufferIndex + 2];
        bufferIndex += 4;

    @Override
    protected int readBytesWireFormat(final byte[] buffer, int bufferIndex) throws SMBProtocolDecodingException {
        final int start = bufferIndex;
        final int structureSize = SMBUtil.readInt2(buffer, bufferIndex);

        if (structureSize != 89) {
            throw new SMBProtocolDecodingException("Structure size is not 89");
        }

        this.oplockLevel = buffer[bufferIndex + 2];

     * SMB2 protocol header template with magic number 0xFE 'SMB'
     */
    public static final byte[] SMB2_HEADER = { (byte) 0xFE, (byte) 'S', (byte) 'M', (byte) 'B', // ProtocolId
            (byte) 64, (byte) 0x00, // StructureSize (LE)
            (byte) 0x00, (byte) 0x00, // CreditCharge (reserved 2.0.2)
            (byte) 0x00, (byte) 0x00, // ChannelSequence
            (byte) 0x00, (byte) 0x00, // Reserved

                        "Should throw SMBProtocolDecodingException for invalid structure size");

        assertEquals("Expected structureSize = 9", exception.getMessage());
    }

    @ParameterizedTest
    @ValueSource(ints = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 100, 255, 256, 65535 })

        int written = request.writeBytesWireFormat(buffer, 0);

        // Then
        assertEquals(32, written);

        // Verify complete structure
        assertEquals(32, SMBUtil.readInt2(buffer, 0)); // StructureSize
        assertEquals(0x0001, SMBUtil.readInt2(buffer, 2)); // Flags
        assertEquals(8192, SMBUtil.readInt4(buffer, 4)); // OutputBufferLength
        // FileId at offset 8-23

    @DisplayName("Should throw exception for invalid structure size")
    @ValueSource(ints = { 0, 1, 64, 66, 128 })
    void testReadBytesWireFormatInvalidStructureSize(int structureSize) {
        // Given
        byte[] buffer = new byte[256];
        SMBUtil.writeInt2(structureSize, buffer, 0);

        // When & Then
        assertThrows(SMBProtocolDecodingException.class, () -> response.readBytesWireFormat(buffer, 0), "Structure size is not 65");

            long chtime, long allocSize, long eof, int attrs, byte[] fileId) {
        byte[] body = new byte[2 + 2 + 4 + 8 + 8 + 8 + 8 + 8 + 8 + 4 + 4 + 16 + 4 + 4];
        int i = 0;
        SMBUtil.writeInt2(89, body, i); // StructureSize
        body[i + 2] = oplock;
        body[i + 3] = openFlags;
        i += 4;

        SMBUtil.writeInt4(createAction, body, i); // CreateAction
        i += 4;