winsock IO模型 重叠端口
用事件通知方式实现的重叠I/O模型
#include <winsock2.h>
#include <stdio.h>
#define PORT 5150
#define MSGSIZE 1024
#pragma comment(lib, "ws2_32.lib")
typedef struct
{
WSAOVERLAPPED overlap;
WSABUF Buffer;
char szMessage[MSGSIZE];
DWORD NumberOfBytesRecvd;
DWORD Flags;
}PER_IO_OPERATION_DATA, *LPPER_IO_OPERATION_DATA;
int g_iTotalConn = 0;
SOCKET g_CliSocketArr[MAXIMUM_WAIT_OBJECTS];
WSAEVENT g_CliEventArr[MAXIMUM_WAIT_OBJECTS];
LPPER_IO_OPERATION_DATA g_pPerIODataArr[MAXIMUM_WAIT_OBJECTS];
DWORD WINAPI WorkerThread(LPVOID);
void Cleanup(int);
int main()
{
WSADATA wsaData;
SOCKET sListen, sClient;
SOCKADDR_IN local, client;
DWORD dwThreadId;
int iaddrSize = sizeof(SOCKADDR_IN);
// Initialize Windows Socket library
WSAStartup(0x0202, &wsaData);
// Create listening socket
sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
// Bind
local.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
local.sin_family = AF_INET;
local.sin_port = htons(PORT);
bind(sListen, (struct sockaddr *)&local, sizeof(SOCKADDR_IN));
// Listen
listen(sListen, 3);
// Create worker thread
CreateThread(NULL, 0, WorkerThread, NULL, 0, &dwThreadId);
while (TRUE)
{ // Accept a connection
sClient = accept(sListen, (struct sockaddr *)&client, &iaddrSize);
printf("Accepted client:%s:%d\n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));
g_CliSocketArr[g_iTotalConn] = sClient; // Allocate a PER_IO_OPERATION_DATA structure
g_pPerIODataArr[g_iTotalConn] = (LPPER_IO_OPERATION_DATA)HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(PER_IO_OPERATION_DATA));
g_pPerIODataArr[g_iTotalConn]->Buffer.len = MSGSIZE;
g_pPerIODataArr[g_iTotalConn]->Buffer.buf = g_pPerIODataArr[g_iTotalConn]->szMessage;
g_CliEventArr[g_iTotalConn] = g_pPerIODataArr[g_iTotalConn]->overlap.hEvent = WSACreateEvent();
// Launch an asynchronous operation
WSARecv( g_CliSocketArr[g_iTotalConn], &g_pPerIODataArr[g_iTotalConn]->Buffer, 1, &g_pPerIODataArr[g_iTotalConn]->NumberOfBytesRecvd, &g_pPerIODataArr[g_iTotalConn]->Flags, &g_pPerIODataArr[g_iTotalConn]->overlap, NULL); g_iTotalConn++; } closesocket(sListen); WSACleanup(); return 0; }
DWORD WINAPI WorkerThread(LPVOID lpParam)
{ int ret, index;
DWORD cbTransferred;
while (TRUE)
{
ret = WSAWaitForMultipleEvents(g_iTotalConn, g_CliEventArr, FALSE, 1000, FALSE);
if (ret == WSA_WAIT_FAILED || ret == WSA_WAIT_TIMEOUT)
{
continue;
}
index = ret - WSA_WAIT_EVENT_0; WSAResetEvent(g_CliEventArr[index]);
WSAGetOverlappedResult( g_CliSocketArr[index], &g_pPerIODataArr[index]->overlap, &cbTransferred, TRUE, &g_pPerIODataArr[g_iTotalConn]->Flags);
if (cbTransferred == 0)
{ // The connection was closed by client
Cleanup(index);
}
else
{ // g_pPerIODataArr[index]->szMessage contains the received data
g_pPerIODataArr[index]->szMessage[cbTransferred] = '\0';
send(g_CliSocketArr[index], g_pPerIODataArr[index]->szMessage,\ cbTransferred, 0);
// Launch another asynchronous operation
WSARecv( g_CliSocketArr[index], &g_pPerIODataArr[index]->Buffer, 1, &g_pPerIODataArr[index]->NumberOfBytesRecvd, &g_pPerIODataArr[index]->Flags, &g_pPerIODataArr[index]->overlap, NULL); } }
return 0;
}
void Cleanup(int index)
{
closesocket(g_CliSocketArr[index]);
WSACloseEvent(g_CliEventArr[index]);
HeapFree(GetProcessHeap(), 0, g_pPerIODataArr[index]);
if (index < g_iTotalConn - 1)
{
g_CliSocketArr[index] = g_CliSocketArr[g_iTotalConn - 1];
g_CliEventArr[index] = g_CliEventArr[g_iTotalConn - 1];
g_pPerIODataArr[index] = g_pPerIODataArr[g_iTotalConn - 1];
}
g_pPerIODataArr[--g_iTotalConn] = NULL; }
这个模型与上述其他模型不同的是它使用Winsock2提供的异步I/O函数WSARecv。在调用WSARecv时,指定一个 WSAOVERLAPPED结构,这个调用不是阻塞的,也就是说,它会立刻返回。一旦有数据到达的时候,被指定的WSAOVERLAPPED结构中的 hEvent被Signaled。由于下面这个语句 g_CliEventArr[g_iTotalConn] = g_pPerIODataArr[g_iTotalConn]->overlap.hEvent; 使 得与该套接字相关联的WSAEVENT对象也被Signaled,所以WSAWaitForMultipleEvents的调用操作成功返回。我们现在应 该做的就是用与调用WSARecv相同的WSAOVERLAPPED结构为参数调用WSAGetOverlappedResult,从而得到本次I/O传 送的字节数等相关信息。在取得接收的数据后,把数据原封不动的发送到客户端,然后重新激活一个WSARecv异步操作。