攔截網路卡封包並且對封包內容進行分析 Part 1

2010-07-08

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code samples
2010-11-20

Hold up packages from network adepter and analyze it. Part 1

在這篇文章之中

我們直接調用socket來取得經由網路卡出入的封包

並且對封包的內容進行分析

我們先來看看取得封包的方式

首先建立一個socket

並且用 IOControl 這個成員函式來進行低階的控制設定

另外為了方便以後應用在多執行緒的程式上

我們採用非同步的方式來接收訊息

詳細的內容可以參考以下連結

http://msdn.microsoft.com/zh-tw/library/system.net.sockets.socket(v=VS.80).aspx

	namespace WindowsFormsApplication1
{
    public class SocketMonitor
    {
        private Queue<AnalyzePackage> _qPackage;
        
        private Socket _mSocket;

        private AnalyzePackage _mPackage;

        private AnalyzePackage _mGetPackage;

        private readonly IPAddress _IP;

        private const int IOC_VENDOR = 0x18000000;

        private const int IOC_IN = -2147483648;
        
        private const int SIO_RCVALL = IOC_IN | IOC_VENDOR | 1;

        private byte[] _byBuff;

        public SocketMonitor(string IP) : this(IPAddress.Parse(IP)) { }


        /// <summary>
        /// Listening your network divice
        /// </summary>
        /// <param name="IP"></param>
        public SocketMonitor(IPAddress IP)
        {
            _IP = IP;

            _qPackage = new Queue<AnalyzePackage>(500);

            _byBuff = new byte[1024];

            _mSocket = new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.IP);

            _mSocket.Bind(new IPEndPoint(_IP, 0)); // 0 will be listening all of ports.
            
            _mSocket.IOControl(SIO_RCVALL, BitConverter.GetBytes((int)1), null);

            this.BeginReceive();
        }


        /// <summary>
        /// recurrent
        /// </summary>
        private void BeginReceive()
        {
            _mSocket.BeginReceive(_byBuff, 0, _byBuff.Length, SocketFlags.None, new AsyncCallback(OnReceive), null);
        }


        /// <summary>
        /// It will be called when you recive data
        /// </summary>
        /// <param name="SyncData"></param>
        private void OnReceive(IAsyncResult SyncData)
        {
            // get data length
            int iRecvLen_ = _mSocket.EndReceive(SyncData);


            _mPackage = new AnalyzePackage(_byBuff, iRecvLen_);

            lock (_qPackage)
            {
                _qPackage.Enqueue(_mPackage);
            }

            this.BeginReceive();    
        }


        /// <summary>
        /// Get package content from the queue.
        /// </summary>
        /// <returns></returns>
        public AnalyzePackage GetPackage()
        {
            _mGetPackage = null;

            lock (_qPackage)
            {
                if (_qPackage.Count!=0)
                    _mGetPackage = _qPackage.Dequeue();
            }

            return _mGetPackage;
        }


        /// <summary>
        /// Get count of the queue.
        /// </summary>
        public int PackageCount
        {
            get
            {
                return _qPackage.Count;
            }        
        }
    }
}

當每次取得資料時

OnReceive就會被呼叫

然後取得資料內容

接下來要做的

就是針對資料內容進行分析了

接續下篇…

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