C# NetworkStream 数据丢失

Question

我目前正在从事一个网络项目，我在其中制定了一个二进制协议(protocol)。我的数据包看起来像这样:[1 字节类型][2 字节索引][2 字节长度][长度字节数据]

这是我接收数据包的代码:

NetworkStream clientStream= Client.GetStream();
while (Client.Connected)
{
    Thread.Sleep(10);
    try
    {
        if (clientStream.DataAvailable)
        {
            byte[] infobuffer = new byte[5];
            int inforead = clientStream.Read(infobuffer, 0, 5);
            if (inforead < 5) { continue; }
            byte[] rawclient = new byte[2];
            Array.Copy(infobuffer, 1, rawclient, 0, 2);
            PacketType type = (PacketType)Convert.ToSByte(infobuffer[0]);
            int clientIndex = BitConverter.ToInt16(rawclient, 0);
            int readLength = BitConverter.ToInt16(infobuffer, 3);
            byte[] readbuffer = new byte[readLength];
            int count_read = clientStream.Read(readbuffer, 0, readLength);
            byte[] read_data = new byte[count_read];
            Array.Copy(readbuffer, read_data, count_read);

            HandleData(read_data, type, clientIndex);
        }
    }
    catch (Exception ex)
    {
        Console.ForegroundColor = ConsoleColor.Red;
        Console.WriteLine("[E] " + ex.GetType().ToString());
        Console.ResetColor();
        break;
    }
}

嗯，一切正常...只要我在 127.0.0.1 上运行它。一旦我尝试长距离测试它，数据包就会以某种方式丢失，并且我在将第一个字节转换为 PacketType 的行上遇到溢出异常。此外，如果我尝试将其他值转换为 int16，我会得到非常奇怪的值。

我假设流在到达服务器的途中以某种方式丢失了一些字节，但这是真的吗？或者这只是我在代码某处的一个小错误？

编辑:我现在编辑了代码，现在它一直读取到它的 5 个字节。但是我仍然在长距离上遇到同样的异常......

NetworkStream clientStream = Client.GetStream();
while (Client.Connected)
{
    Thread.Sleep(10);
    try
    {
        if (clientStream.DataAvailable)
        {
            int totalread = 0;
            byte[] infobuffer = new byte[5];
            while (totalread < 5)
            {
                int inforead = clientStream.Read(infobuffer, totalread, 5 - totalread);
                if (inforead == 0)
                { break; }
                totalread += inforead;
            }
            byte[] rawclient = new byte[2];
            Array.Copy(infobuffer, 1, rawclient, 0, 2);
            PacketType type = (PacketType)Convert.ToSByte(infobuffer[0]);
            int clientIndex = BitConverter.ToInt16(rawclient, 0);
            int readLength = BitConverter.ToInt16(infobuffer, 3);
            byte[] readbuffer = new byte[readLength];
            int count_read = clientStream.Read(readbuffer, 0, readLength);
            byte[] read_data = new byte[count_read];
            Array.Copy(readbuffer, read_data, count_read);

            HandleData(read_data, type, clientIndex);
        }
    }
    catch (Exception ex)
    {
        Console.ForegroundColor = ConsoleColor.Red;
        Console.WriteLine("[E] " + ex.GetType().ToString());
        Console.ResetColor();
        break;
    }
}

PacketType 是一个枚举:

public enum PacketType
{
    AddressSocks5 = 0,
    Status = 1,
    Data = 2,
    Disconnect = 3,
    AddressSocks4 = 4
}

Answer 1

你在这里做错了很多事情......这么多错误......甚至从哪里开始......

第一次网络投票？真的吗？在当今时代，这只是进行网络事件的一种幼稚方式。但我不会对此喋喋不休。

其次，使用这种类型的协议(protocol)，很容易“不同步”，一旦发生，就无法恢复同步。这通常是通过某种“成帧协议(protocol)”来完成的，它提供了一个唯一的字节序列，您可以使用它来指示帧的开始和结束，这样如果您发现自己不同步，您可以读取数据直到您得到恢复同步。是的，您会丢失数据，但如果不同步，您就已经丢失了数据。

第三，你在这里并没有真正做任何大事，所以我无耻地从这里窃取了“ReadWholeArray”代码，它不是最有效的，但它有效并且那里还有其他代码可能有帮助:

http://www.yoda.arachsys.com/csharp/readbinary.html

注意:您没有提及如何在另一侧序列化长度、类型和索引值。所以使用 BitConverter 可能是错误的，这取决于它是如何完成的。

if (clientStream.DataAvailable)
{
    byte[] data = new byte[5];
    // if it can't read all 5 bytes, it throws an exception
    ReadWholeArray(clientStream, data);
    PacketType type = (PacketType)Convert.ToSByte(data[0]);
    int clientIndex = BitConverter.ToInt16(data, 1);
    int readLength = BitConverter.ToInt16(data, 3);

    byte[] rawdata = new byte[readLength];
    ReadWholeArray(clientStream, rawdata); 
    HandleData(rawdata, type, clientIndex);
}

/// <summary>
/// Reads data into a complete array, throwing an EndOfStreamException
/// if the stream runs out of data first, or if an IOException
/// naturally occurs.
/// </summary>
/// <param name="stream">The stream to read data from</param>
/// <param name="data">The array to read bytes into. The array
/// will be completely filled from the stream, so an appropriate
/// size must be given.</param>
public static void ReadWholeArray (Stream stream, byte[] data)
{
    int offset=0;
    int remaining = data.Length;
    while (remaining > 0)
    {
        int read = stream.Read(data, offset, remaining);
        if (read <= 0)
            throw new EndOfStreamException 
                (String.Format("End of stream reached with {0} bytes left to read", remaining));
        remaining -= read;
        offset += read;
    }
}