C# 利用SharpPcap实现网络包捕获嗅探

本文是利用SharpPcap实现网络包的捕获的小例子，实现了端口监控，数据包捕获等功能，主要用于学习分享。

什么是SharpPcap？

SharpPcap 是一个.NET 环境下的网络包捕获框架，基于著名的 pcap/WinPcap 库开发。提供了捕获、注入、分析和构建的功能，适用于 C# 和 VB NET 开发语言。

SharpPcap有两部分组成：1> SharpPcap.dll 负责数据的捕获  2> PacketDotNet.dll负责数据包的解析

思路：

1. 通过进程名字获取对应的端口号。
2. SharpPcap获取对应的数据包，通过解析数据包过滤相关的端口。

涉及知识点：

• Process 获取相关进程信息。
• netstat命令：netstat -ano|find "3844" 获取进程对应的端口
• SharpPcap相关信息：
  • 通过CaptureDeviceList的静态方法获取设备列表。
  • 通过OnPacketArrival事件接收数据包。
  • 通过PacketDotNet来解析数据包

效果图下：

SharpPcap核心代码：

         /// <summary>
         /// 开始捕捉
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void btnStart_Click(object sender, EventArgs e)
         {
             if (this.combDevice.SelectedIndex > -)
             {
                 StartCapture(this.combDevice.SelectedIndex);
                 this.btnStart.Enabled = false;
                 this.btnStop.Enabled = true;
             }
             else {
                 MessageBox.Show(this,"请选择一个设备","提示",MessageBoxButtons.OK);
             }
         }

         /// <summary>
         /// 停止捕捉
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void btnStop_Click(object sender, EventArgs e)
         {
             Shutdown();
             this.btnStop.Enabled = false;
             this.btnStart.Enabled = true;
         }

         private void StartCapture(int itemIndex)
         {
             packetCount = ;
             device = CaptureDeviceList.Instance[itemIndex];
             packetStrings = new Queue<PacketWrapper>();
             bs = new BindingSource();
             dgvData.DataSource = bs;
             LastStatisticsOutput = DateTime.Now;

             // start the background thread
             backgroundThreadStop = false;
             backgroundThread = new Thread(BackgroundThread);
             backgroundThread.Start();

             // setup background capture
             device.OnPacketArrival += new PacketArrivalEventHandler(device_OnPacketArrival);
             device.OnCaptureStopped +=  new CaptureStoppedEventHandler(device_OnCaptureStopped);
             device.Open();

             // tcpdump filter to capture only TCP/IP packets
             string filter = "ip and tcp";
             device.Filter = filter;

             // force an initial statistics update
             captureStatistics = device.Statistics;
             UpdateCaptureStatistics();

             // start the background capture
             device.StartCapture();

             btnStop.Enabled = true;
         }

         /// <summary>
         /// 设备接收事件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void device_OnPacketArrival(object sender, CaptureEventArgs e)
         {
             // print out periodic statistics about this device
             var Now = DateTime.Now;
             var interval = Now - LastStatisticsOutput;
             if (interval > new TimeSpan(, , ))
             {
                 Console.WriteLine("device_OnPacketArrival: " + e.Device.Statistics);
                 captureStatistics = e.Device.Statistics;
                 statisticsUiNeedsUpdate = true;
                 LastStatisticsOutput = Now;
             }

             lock (QueueLock)
             {
                 PacketQueue.Add(e.Packet);
             }
         }

         /// <summary>
         /// 设备停止事件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="status"></param>
         private void device_OnCaptureStopped(object sender, CaptureStoppedEventStatus status)
         {
             if (status != CaptureStoppedEventStatus.CompletedWithoutError)
             {
                 MessageBox.Show("Error stopping capture", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
             }
         }

         private void UpdateCaptureStatistics()
         {
             tlblStatistic.Text = string.Format("接收包: {0}, 丢弃包: {1}, 接口丢弃包: {2}", captureStatistics.ReceivedPackets,captureStatistics.DroppedPackets, captureStatistics.InterfaceDroppedPackets);
         }

关于SharpPcap手册

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