iocp模型:基于iocp的SOCKET通讯软件Software的设计

完成端口基本上公认为种在windows服务平台上比较成熟和高效IO思路方法利用完成端口进行重叠I/O技术在WindowsNT和WIndows2000上提供了真正可扩展性完成端口和Windows Socket2.0结合可以开发出支持大量连接网络服务

　　首先来看看重叠I/O(Overlapped I/O):

　　重叠I/O(Overlapped I/O)机制允许发起个操作然后在操作完成的后接受到信息对于那种需要很长时间才能完成操作来说重叠IO机制尤其有用发起重叠操作线程在重叠请求发出后就可以自由做别事情了

　　在WinNT和Win2000上提供真正可扩展I/O模型就是使用完成端口(Completion Port)重叠I/O

　　接下来看看完成端口(Completion Ports )

　　其实可以把完成端口看成系统维护个队列操作系统把重叠IO操作完成事件通知放到该队列里由于是暴露 “操作完成”事件通知所以命名为“完成端口”(COmpletion Ports)个被创建后可以在任何时刻和个完成端口联系起来

　　般来说个应用可以创建多个工作线程来处理完成端口上通知事件工作线程数量依赖于具体需要但是在理想情况下应该对应个CPU创建个线程在完成端口理想模型中每个线程都可以从系统获得个“原子”性时间片轮番运行并检查完成端口线程切换是额外开销在实际开发时候还要考虑这些线程是否牵涉到其他堵塞操作情况如果某线程进行堵塞操作系统则将其挂起让别线程获得运行时间因此如果有这样情况可以多创建几个线程来尽量利用时间

　　总的开发个可扩展Winsock服务器并非十分困难主要是开始个监听,接收连接并且进行重叠发送和接收IO操作最大挑战就是管理系统资源限制重叠Io数量避免内存危机遵循这几个原则就能帮助你开发高性能可扩展服务

　　接收缓冲接收事件仅仅在AcceptEx中发生保证每个都有个接收缓冲不会造成什么危害旦客户端/服务器在最初次请求(由AcceptEx完成)的后进行交互发送更多数据那么取消接收缓冲更是个很不好做法除非你能保证这些数据都是在每个连接重叠IO接收里完成

服务器器端代码如下:

# <stdio.h>
# <winsock2.h>
#pragma comment(lib, "ws2_32.lib")
typedef struct _OVERLAPPEDPLUS
{
OVERLAPPED ol;
SOCKET ;
nOpCode;
WSABUF wsaBuf;
DWORD dwFlags;
DWORD dwBytes;
char pBuf[4096];
}OVERLAPPEDPLUS, *POVERLAPPEDPLUS;

DWORD WINAPI ServerWorkerThread(LPVOID CompletionPortID);

void
{
WORD wVersionRequested;
WSADATA wsaData;
err;

wVersionRequested = MAKEWORD( 2, 2 );

err = WSAStartup( wVersionRequested, &wsaData );
( err != 0 )
{
prf("WSAStartup errors!\n");
;
}
( LOBYTE( wsaData.wVersion ) != 2 ||
HIBYTE( wsaData.wVersion ) != 2 )
{
WSACleanup( );
;
}

SOCKET sockSvr = WSASocket(AF_INET, SOCK_STREAM, 0, 0, 0, WSA_FLAG_OVERLAPPED);
(INVALID_SOCKET sockSvr)
{
prf("WSASocket errors!\n");
;
}

SOCKADDR_IN addrSvr;
ZeroMemory(&addrSvr, (SOCKADDR_IN));
addrSvr.sin_family = AF_INET;
addrSvr.sin_port = htons(6000);
addrSvr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
nRet = bind(sockSvr, (SOCKADDR*)&addrSvr, (SOCKADDR));
(SOCKET_ERROR nRet)
{
prf("bind errors!\n");
;
}

nRet = listen(sockSvr, 500);
(SOCKET_ERROR nRet)
{
prf("listen errors!\n");
;
}

HANDLE hCompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, NULL, 0);
(!hCompletionPort)
{
prf("CreateIoCompletionPort errors!\n");
;
}

SYSTEM_INFO Info;
UINT i = 0;
DWORD dwThreadID = 0;
GetInfo(&Info);
for(i=0; i<Info.dwNumberOfProcessors*2; i)
{
HANDLE ThreadHandle = CreateThread(NULL, 0, ServerWorkerThread, hCompletionPort, 0, &dwThreadID);
(ThreadHandle NULL)
{
prf("CreateThread failed with error %d\n", GetLastError);
;
}
CloseHandle(ThreadHandle);
}

while(true)
{
SOCKADDR_IN addrAccept;
ZeroMemory(&addrAccept, (SOCKADDR_IN));
nSockLen = (SOCKADDR);

SOCKET sockAccept = WSAAccept(sockSvr, (SOCKADDR*)&addrAccept, &nSockLen, 0, 0);
(INVALID_SOCKET sockSvr)
{
prf("WSAAccept errors!\n");
;
}

(NULLCreateIoCompletionPort((HANDLE)sockAccept, hCompletionPort, (DWORD)sockSvr, 0))
{
prf("CreateIoCompletionPort errors!\n");
;
}

OVERLAPPEDPLUS* pOlp = OVERLAPPEDPLUS;
ZeroMemory(pOlp, (OVERLAPPEDPLUS));
ZeroMemory(&(pOlp->ol), (OVERLAPPED));
pOlp-> = sockAccept;
pOlp->dwFlags = 0;
pOlp->wsaBuf.buf = pOlp->pBuf;


pOlp->wsaBuf.len = 4096;
pOlp->nOpCode = FD_READ;

nRet = WSARecv(pOlp->, &(pOlp->wsaBuf), 1, &(pOlp->dwBytes), &(pOlp->dwFlags), &(pOlp->ol), NULL);
(SOCKET_ERROR nRet)
{
(WSAGetLastError != ERROR_IO_PENDING)
{
prf("WSARecv failed with error %d\n", WSAGetLastError);
;
}
}
}
;
}

DWORD WINAPI ServerWorkerThread(LPVOID CompletionPortID)
{
HANDLE hCompletionPort = (HANDLE) CompletionPortID;
void* re;
DWORD berByte;
OVERLAPPED* pOl;

while(TRUE)
{
BOOL bRet = GetQueuedCompletionStatus(hCompletionPort, &berByte, (LPDWORD)&re, (LPOVERLAPPED*)&pOl, INFINITE);
(!bRet)
{
prf("GetQueuedCompletionStatus failed with error %d\n", GetLastError);
FALSE;
}
(0 berByte)
{
prf("DGFDGDGF\n");
FALSE;
}
OVERLAPPEDPLUS* pOlp = (OVERLAPPEDPLUS*) pOl;
switch(pOlp->nOpCode)
{
FD_READ:
prf("%s\n", pOlp->wsaBuf.buf);
;
default:
prf("no data!!\n");
}

pOlp->nOpCode = FD_READ;
WSARecv(pOlp->, &(pOlp->wsaBuf), 1, &(pOlp->dwBytes), &(pOlp->dwFlags), &(pOlp->ol), NULL);
}
TRUE;
}

测试客户端代码如下:

// SocketClientDlg.cpp : 实现文件
//
# "stdafx.h"
# "SocketClient.h"
# ".\clientdlg.h"
#def _DEBUG
# DEBUG_NEW
#end


// 用于应用“有关”菜单项 CAboutDlg 对话框

CAboutDlg : public CDialog
{
public:
CAboutDlg;

// 对话框数据
enum { IDD = IDD_ABOUTBOX };

protected:
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV 支持

// 实现
protected:
DECLARE_MESSAGE_MAP
};

CAboutDlg::CAboutDlg : CDialog(CAboutDlg::IDD)
{
}

void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{
CDialog::DoDataExchange(pDX);
}

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
END_MESSAGE_MAP


// CSocketClientDlg 对话框



CSocketClientDlg::CSocketClientDlg(CWnd* pParent /*=NULL*/)
: CDialog(CSocketClientDlg::IDD, pParent)
{
m_hIcon = AfxGetApp->LoadIcon(IDR_MAINFRAME);
}

void CSocketClientDlg::DoDataExchange(CDataExchange* pDX)
{
CDialog::DoDataExchange(pDX);
}

BEGIN_MESSAGE_MAP(CSocketClientDlg, CDialog)
ON_WM_SYSCOMMAND
ON_WM_PAINT
ON_WM_QUERYDRAGICON
//}}AFX_MSG_MAP
ON_BN_CLICKED(IDC_SEND, _disibledevent=>ASSERT(IDM_ABOUTBOX < 0xF000);

CMenu* pSysMenu = GetMenu(FALSE);
(pSysMenu != NULL)
{
CString strAboutMenu;
strAboutMenu.LoadString(IDS_ABOUTBOX);
(!strAboutMenu.IsEmpty)
{
pSysMenu->AppendMenu(MF_SEPARATOR);
pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
}
}

// 设置此对话框图标当应用主窗口不是对话框时框架将自动
// 执行此操作
SetIcon(m_hIcon, TRUE); // 设置大图标
SetIcon(m_hIcon, FALSE); // 设置小图标

// TODO: 在此添加额外化代码
WORD wVersionRequested;
WSADATA wsaData;
err;

wVersionRequested = MAKEWORD( 2, 2 );

err = WSAStartup( wVersionRequested, &wsaData );
( err != 0 )
{
MessageBox("WSAStartup errors!\n");
FALSE;
}
( LOBYTE( wsaData.wVersion ) != 2 ||
HIBYTE( wsaData.wVersion ) != 2 )
{
WSACleanup( );
FALSE;
}

sockClient = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0, 0);
(INVALID_SOCKET sockClient)
{
MessageBox(" errors!\n");
FALSE;
}
TRUE; // 除非设置了Control控件焦点否则返回 TRUE
}

void CSocketClientDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
((nID & 0xFFF0) IDM_ABOUTBOX)
{
CAboutDlg dlgAbout;
dlgAbout.DoModal;
}

{
CDialog::OnSysCommand(nID, lParam);
}
}

// 如果向对话框添加最小化按钮则需要下面代码
// 来绘制该图标对于使用文档/视图模型 MFC 应用
// 这将由框架自动完成



void CSocketClientDlg::OnPa
{
(IsIconic)
{
CPaDC dc(this); // 用于绘制设备上下文

SendMessage(WM_ICONERASEBKGND, reerpret_cast<WPARAM>(dc.GetSafeHdc), 0);

// 使图标在工作矩形中居中
cxIcon = GetMetrics(SM_CXICON);
cyIcon = GetMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
x = (rect.Width - cxIcon + 1) / 2;
y = (rect.Height - cyIcon + 1) / 2;

// 绘制图标
dc.DrawIcon(x, y, m_hIcon);
}

{
CDialog::OnPa;
}
}

//当用户拖动最小化窗口时系统此取得光标显示
HCURSOR CSocketClientDlg::OnQueryDragIcon
{
_cast<HCURSOR>(m_hIcon);
}

void CSocketClientDlg::OnBnClickedSend
{
// TODO: 在此添加Control控件通知处理代码
CString strSend;
GetDlgItem(IDC_EDIT_CONTENT)->GetWindowText(strSend);
send(sockClient, strSend, strSend.GetLength+1, 0);


CString strRecord;
GetDlgItem(IDC_EDIT_RECORD)->GetWindowText(strRecord);
strRecord strSend + "\r\n";
GetDlgItem(IDC_EDIT_RECORD)->SetWindowText(strRecord);
GetDlgItem(IDC_EDIT_CONTENT)->SetWindowText("");
}

void CSocketClientDlg::OnBnClickedBtnConnect
{
// TODO: 在此添加Control控件通知处理代码
CIPAddressCtrl* pIPAddressCtrl = (CIPAddressCtrl*)GetDlgItem(IDC_ADDR_SERVER);
CString strAddrServer;
pIPAddressCtrl->GetWindowText(strAddrServer);
SOCKADDR_IN addrSvr;
ZeroMemory(&addrSvr, (SOCKADDR_IN));
addrSvr.sin_family = AF_INET;
addrSvr.sin_port = htons(6000);
addrSvr.sin_addr.S_un.S_addr = inet_addr(strAddrServer);
while(1)
{
nRet = connect(sockClient, (SOCKADDR*)&addrSvr, (SOCKADDR));
(SOCKET_ERROR nRet)
{
continue;
}

{
;
}
}

CEdit* pEditRecord = (CEdit*)GetDlgItem(IDC_EDIT_RECORD);
CString strText;
pEditRecord->GetWindowText(strText);
strText "连接服务器成功！\r\n";
pEditRecord->SetWindowText(strText);
}

延伸阅读

• 2011-4-23-- udpiocp,IOCP-------网络聊天室之 迷惑
• 2008-12-9-- iocp代码:iocp
• 2009-2-12-- iocp模型:IOCP与线程