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我第一次尝试处理数据包和字节，经过许多不同的技术，我至今无法正确获得数据包长度。

代码：

Public Shared Sub Client(packet As Packet)
    Console.WriteLine( _ 
      "Client -> " & _
      packet.Timestamp.ToString("yyyy-MM-dd hh:mm:ss.fff") & _
      " length:" & Convert.ToString(packet.Length))

    'Define Byte Array
    Dim clientPacket As Byte() = packet.Buffer

    ' Open a Binary Reader
    Dim memStream As MemoryStream = New MemoryStream(clientPacket)
    Dim bReader As BinaryReader = New BinaryReader(memStream)

    ' Remove the Ethernet Header
    Dim ethBytes As Byte() = bReader.ReadBytes(14)

    ' Remove the IPv4 Header
    Dim IPv4Bytes As Byte() = bReader.ReadBytes(20)

    ' Remove the TCP Header
    Dim TCPBytes As Byte() = bReader.ReadBytes(20)

    ' Get the packet length
    If clientPacket.Length > 54 Then
        Dim len As UInt32 = bReader.ReadUInt32
        Console.WriteLine(len)
    End If
End Sub

到目前为止，我所有让控制台写入数据长度的尝试都失败了。我验证了字节顺序并实际写出字节以验证我正在处理正确的数据。

示例字节：

00 00 00 24 -> UINT32 是 36 个字节，但我得到一个整数数组，如 3808493568

我怎样才能解决这个问题？

4

1 回答 1

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我同意汉斯的观点，字节序是你的问题。另外，我建议您使用数组BitConverter上的类，比使用流更容易。clientPacket

Dim len As UInt32
Dim arr() As Byte
arr = {0, 0, 0, 24}
len = BitConverter.ToUInt32(arr, 0)
Console.Write(len.ToString) 'returns 402653184

arr = {24, 0, 0, 0}
len = BitConverter.ToUInt32(arr, 0)
Console.Write(len.ToString) 'returns 24

对于您的代码，我认为这可能有效（未经测试）：

If clientPacket.Length > 54 Then
  Dim lenBytes As Byte() = bReader.ReadBytes(4)
  Array.Reverse(lenBytes, 0, 4)
  Dim len As UInt32 = BitConverter.ToUInt32(lenBytes, 0)
于 2014-06-05T02:20:11.220 回答