是否有可能无法收到 WSASend 调用的完成信息？

发布于 2024-10-27 10:33:42 字数 1359 浏览 7 评论 0原文

正如标题所示，在与 I/O 完成端口关联的套接字上进行成功 WSASend 调用是否可能因线程以外的任何原因而不会发布完成结束？

我遇到了一种奇怪的情况，似乎没有为 WSASend 发布完成，这会导致套接字泄漏；应用程序认为套接字的发送仍在等待中并拒绝释放它。

发送代码如下：

void CSocketServer::Write(
    Socket *pSocket,
    CIOBuffer *pBuffer) const
{
    pSocket->AddRef();

    pBuffer->SetOperation(IO_Write_Completed);
    pBuffer->SetupWrite();
    pBuffer->AddRef();

    DWORD dwFlags = 0;
    DWORD dwSendNumBytes = 0;

    if (SOCKET_ERROR == ::WSASend(
        pSocket->m_socket,
        pBuffer->GetWSABUF(), 
        1, 
        &dwSendNumBytes,
        dwFlags,
        pBuffer, 
        NULL))
    {
        DWORD lastError = ::WSAGetLastError();

        if (ERROR_IO_PENDING != lastError)
        {
            pSocket->OnConnectionError(WriteError, pBuffer, lastError);

            pSocket->WriteCompleted();  // this pending write will never complete...

            pSocket->Release();
            pBuffer->Release();
        }
    }
    // Note: even if WSASend returns SUCCESS an IO Completion Packet is 
    // queued to the IOCP the same as if ERROR_IO_PENDING was returned.
    // Thus we need no special handling for the non error return case.
    // See http://support.microsoft.com/default.aspx?scid=kb;en-us;Q192800
    // for details.
}

原文

Like the title says, is it possible for a successful WSASend call on a socket associated with an I/O completion port to not post a completion for any reason other than the thread ending?

I have a strange situation where it looks like a completion isn't being posted for a WSASend, which results in a socket leak; the application thinks a send is still pending for the socket and refuses to release it.

The send code is as follows:

void CSocketServer::Write(
    Socket *pSocket,
    CIOBuffer *pBuffer) const
{
    pSocket->AddRef();

    pBuffer->SetOperation(IO_Write_Completed);
    pBuffer->SetupWrite();
    pBuffer->AddRef();

    DWORD dwFlags = 0;
    DWORD dwSendNumBytes = 0;

    if (SOCKET_ERROR == ::WSASend(
        pSocket->m_socket,
        pBuffer->GetWSABUF(), 
        1, 
        &dwSendNumBytes,
        dwFlags,
        pBuffer, 
        NULL))
    {
        DWORD lastError = ::WSAGetLastError();

        if (ERROR_IO_PENDING != lastError)
        {
            pSocket->OnConnectionError(WriteError, pBuffer, lastError);

            pSocket->WriteCompleted();  // this pending write will never complete...

            pSocket->Release();
            pBuffer->Release();
        }
    }
    // Note: even if WSASend returns SUCCESS an IO Completion Packet is 
    // queued to the IOCP the same as if ERROR_IO_PENDING was returned.
    // Thus we need no special handling for the non error return case.
    // See http://support.microsoft.com/default.aspx?scid=kb;en-us;Q192800
    // for details.
}

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少钕鈤記 2024-11-03 10:33:42

您是否正在使用任何时髦的新功能，例如使用 FILE_SKIP_COMPLETION_PORT_ON_SUCCESS 关闭成功调用的完成功能？

您是否对发送进行了任何形式的流量控制，或者您只是在您愿意的时候发送，并且按照您想要的频率发送？您可能看到的只是缓慢的完成，因为 TCP 堆栈正在执行拥塞控制并且还无法发送您的数据。如果您继续以不受控制的方式发送数据，您通常会遇到完成时间开始变得越来越长的情况。特别是如果您发送数据的速率比 TCP 连接成功将数据发送到另一端的速率快，尤其是当 TCP 窗口不是那么大时。请参阅此处：http://www.lenholgate.com/ blog/2008/07/write-completion-flow-control.html 了解更多信息。

当然，这可能只是您的发送逻辑中的错误，您可以发布一些代码吗？

请注意，使用 FILE_SKIP_COMPLETION_PORT_ON_SUCCESS 时，WSARecv() 和 UDP 存在一个已知错误（因此与您的问题完全无关），如果数据报大于您所设置的缓冲区，则会出现您所描述的情况供应和 WSARecv() 调用将生成一个 WSAEMOREDATA；请参阅此处： http://www.lenholgate.com/blog/2010/01/file-skip-completion-port-on-success-and-datagram-socket-read-errors.html