Socket 网络模型之Select篇
C++代码
// write by larry
// 2009-8-20
// This is server using select model.
#include "stdafx.h"
#include <winsock.h>
#include <stdio.h>
#define PORT 5150
#define MSGSIZE 1024
#pragma comment(lib, "ws2_32.lib")
int g_iTotalConn = 0;
SOCKET g_CliSocketArr[FD_SETSIZE];
DWORD WINAPI WorkerThread(LPVOID lpParam);
int main(int argc, char* argv[])
{
WSADATA wsaData;
SOCKET sListen, sClient;
SOCKADDR_IN local, client;
int iAddrSize = sizeof(SOCKADDR_IN);
DWORD dwThreadId;
// Initialize windows socket library
WSAStartup(0x0202, &wsaData);
// Create listening socket
sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
// Bind
local.sin_family = AF_INET;
local.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
local.sin_port = htons(PORT);
bind(sListen, (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, (sockaddr*)&client, &iAddrSize);
printf("Accepted client:%s:%d\n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));
// Add socket to g_CliSocketArr
g_CliSocketArr[g_iTotalConn++] = sClient;
}
return 0;
}
DWORD WINAPI WorkerThread(LPVOID lpParam)
{
int i;
fd_set fdread;
int ret;
struct timeval tv = {1, 0};
char szMessage[MSGSIZE];
while (TRUE)
{
FD_ZERO(&fdread);
for (i = 0; i < g_iTotalConn; i++)
{
FD_SET(g_CliSocketArr[i], &fdread);
}
// We only care read event
ret = select(0, &fdread, NULL, NULL, &tv);
if (ret == 0)
{
// Time expired
continue;
}
for (i = 0; i < g_iTotalConn; i++)
{
if (FD_ISSET(g_CliSocketArr[i], &fdread))
{
// A read event happened on g_CliSocketArr
ret = recv(g_CliSocketArr[i], szMessage, MSGSIZE, 0);
if (ret == 0 || (ret == SOCKET_ERROR && WSAGetLastError() == WSAECONNRESET))
{
// Client socket closed
printf("Client socket %d closed.\n", g_CliSocketArr[i]);
closesocket(g_CliSocketArr[i]);
if (i < g_iTotalConn-1)
{
g_CliSocketArr[i--] = g_CliSocketArr[--g_iTotalConn];
}
}
else
{
// We reveived a message from client
szMessage[ret] = '\0';
send(g_CliSocketArr[i], szMessage, strlen(szMessage), 0);
}
}
}
}
}
// writeby larry
//2009-8-20
// Thisis server using select model.
#include"stdafx.h"
#include<winsock.h>
#include<stdio.h>
#definePORT 5150
#defineMSGSIZE 1024
#pragmacomment(lib, "ws2_32.lib")
intg_iTotalConn = 0;
SOCKETg_CliSocketArr[FD_SETSIZE];
DWORDWINAPI WorkerThread(LPVOID lpParam);
intmain(int argc, char* argv[])
{
WSADATA wsaData;
SOCKET sListen, sClient;
SOCKADDR_IN local, client;
int iAddrSize = sizeof(SOCKADDR_IN);
DWORD dwThreadId;
// Initialize windows socket library
WSAStartup(0x0202, &wsaData);
// Create listening socket
sListen = socket(AF_INET, SOCK_STREAM,IPPROTO_TCP);
// Bind
local.sin_family = AF_INET;
local.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
local.sin_port = htons(PORT);
bind(sListen, (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,(sockaddr*)&client, &iAddrSize);
printf("Acceptedclient:%s:%d\n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));
// Add socket to g_CliSocketArr
g_CliSocketArr[g_iTotalConn++] = sClient;
}
return 0;
}
DWORDWINAPI WorkerThread(LPVOID lpParam)
{
int i;
fd_set fdread;
int ret;
struct timeval tv = {1, 0};
char szMessage[MSGSIZE];
while (TRUE)
{
FD_ZERO(&fdread);
for (i = 0; i < g_iTotalConn; i++)
{
FD_SET(g_CliSocketArr[i], &fdread);
}
// We only care read event
ret = select(0, &fdread, NULL, NULL,&tv);
if (ret == 0)
{
// Time expired
continue;
}
for (i = 0; i < g_iTotalConn; i++)
{
if (FD_ISSET(g_CliSocketArr[i],&fdread))
{
// A read event happened ong_CliSocketArr
ret = recv(g_CliSocketArr[i],szMessage, MSGSIZE, 0);
if (ret == 0 || (ret == SOCKET_ERROR&& WSAGetLastError() == WSAECONNRESET))
{
// Client socket closed
printf("Client socket %dclosed.\n", g_CliSocketArr[i]);
closesocket(g_CliSocketArr[i]);
if (i < g_iTotalConn-1)
{
g_CliSocketArr[i--] =g_CliSocketArr[--g_iTotalConn];
}
}
else
{
// We reveived a message fromclient
szMessage[ret] = '\0';
send(g_CliSocketArr[i],szMessage, strlen(szMessage), 0);
}
}
}
}
}
这是异步模型中最简单的一种，服务器端的几个主要流程如下：
1.创建监听套接字，绑定，监听；
2.创建工作者线程；
3.创建一个套接字数组，用来存放当前所有活动的客户端套接字，每accept一个连接就更新一次数组；
4.接受客户端的连接。