如何在TCP客户端（套接字）上实现VB.NET中的TCP KeepAlive

我想实现TCP KeepAlive以通过运行计时器来检查丢弃的连接。在我的情况下，我有一个TCP客户端（使用套接字类）和第三方服务器（我没有控制它）。如何在我的TCP客户端上使用TCP KeepAlive以检查连接状态？如何在TCP客户端（套接字）上实现VB.NET中的TCP KeepAlive

目前我已启用TCP KeepAlive选项！

tcpsocket.Connect(IPEndPoint) 
tcpSocket.SetSocketOption(SocketOptionLevel.Tcp,SocketOptionName.KeepAlive,1);

搜索互联网上我发现这个过程，应该工作，但我想知道如何我可以用它在我的TCP客户端？

Private Shared Function SetKeepAlive(ByRef tcpSocket As Socket, ByVal keepAliveTime As UInteger, ByVal keepAliveInterval As UInteger) As Boolean 
    ' Pack three params into 12-element byte array; not sure about endian issues on non-Intel 
    Dim SIO_KEEPALIVE_VALS(11) As Byte 
    Dim keepAliveEnable As UInteger = 1 
    If (keepAliveTime = 0 Or keepAliveInterval = 0) Then keepAliveEnable = 0 
    ' Bytes 00-03 are 'enable' where '1' is true, '0' is false 
    ' Bytes 04-07 are 'time' in milliseconds 
    ' Bytes 08-12 are 'interval' in milliseconds 
    Array.Copy(BitConverter.GetBytes(keepAliveEnable), 0, SIO_KEEPALIVE_VALS, 0, 4) 
    Array.Copy(BitConverter.GetBytes(keepAliveTime), 0, SIO_KEEPALIVE_VALS, 4, 4) 
    Array.Copy(BitConverter.GetBytes(keepAliveInterval), 0, SIO_KEEPALIVE_VALS, 8, 4) 

    Try 
    Dim result() As Byte = BitConverter.GetBytes(CUInt(0)) ' Result needs 4-element byte array? 
    tcpSocket.IOControl(IOControlCode.KeepAliveValues, SIO_KEEPALIVE_VALS, result) 
    Catch e As Exception 
    Return False 
    End Try 
    Return True 
End Function

任何帮助，将不胜感激。

PS：我是编程新手，请原谅我的编码错误。

来源

2012-04-24 Operagust

最后，我设法使用TCP KeepAlive。因此，为了实现这一点，我刚刚叫mainform_load程序：

 tcpSocket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp) 
     tcpSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, True) 
     SetKeepAlive(tcpSocket, keepalivetime, keepaliveinterval) 
     Try 
      tcpSocket.Connect(ipEndPoint) 
     Catch e As SocketException 
      ... 
     End Try

我已使用Wireshark检查，我注意到了发送的数据包。

来源

2012-04-25 08:08:33 Operagust

如何在TCP客户端（套接字）上实现VB.NET中的TCP KeepAlive

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