/*
TCP Select Chat Server
Author :Andrew Huang
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
#include <sys/select.h>
/* According to earlier standards */
#include <sys/time.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
static fd_set user_list; //用来表示在线的用户
static int max_fd =0;
static void process_fn(int client_fd)
{
int len,fd;
char buf[1024];
printf("RECV from socket %d\n",client_fd);
//第五步:与客户端在新的socket进行通讯
//注意,是从client_fd,
len = recv(client_fd,buf,sizeof(buf),0);
if(len <= 0)
{
close(client_fd);
FD_CLR(client_fd,&user_list); //从在线用户表中清除当前的socket
fprintf(stdout,"CLOSE socket %d,len %d\n",client_fd,len);
return ;
}
buf[len] = 0;
fprintf(stdout,"RECV(%d):\"%s\"\n",client_fd,buf);
//轮播聊天信息
for(fd = 3; fd <= max_fd ; fd++)
{
if(!FD_ISSET(fd,&user_list) || (fd == client_fd))
continue;
send(fd,buf,len,0);
}
}
int main(int argc ,char * argv[])
{
unsigned short port = 9000;
int listen_fd ,ret;
int client_fd,fd;
pthread_t pth;
fd_set fdset;
struct sockaddr_in addr; //ipv4的地址结构
struct sockaddr_in client_addr ;
socklen_t addr_len;
int len,maxfd ;
if(argc >1)
{
port = (unsigned short)atoi(argv[1]);
}
//第一步:创建一个IPV4,TCP,可以运行所有协议的SOCKET
listen_fd = socket(PF_INET,SOCK_STREAM,0);
if(listen_fd == -1)
{
perror("socket");
return -1;
}
//第二步:用bind来指定端口
memset(&addr,0,sizeof(addr));
addr.sin_port = htons(port); //转成网络序的端口
addr.sin_family = AF_INET; //ipv4的地址类型
//addr.sin_addr.s_addr = inet_addr("0.0.0.0"); //bind 的sin_addr表示在哪一个网卡上有效,
//绑定在0.0.0.0上表示这个SOCKET在所有网卡侦听
addr.sin_addr.s_addr = INADDR_ANY; //INADDR_ANY = 0 = inet_addr("0.0.0.0")
if(bind(listen_fd,(const struct sockaddr *)&addr,sizeof(addr)) == -1)
{
perror("bind");
close(listen_fd);
return -2;
}
//第三步: 通知内核里的TCP/IP协议栈,让这个SOCKET开始侦听网络上的请求
// listen只是通知一下,通知成功立即执行后面代码
if(listen(listen_fd,20) == -1)
{
perror("listen");
close(listen_fd);
return -3;
}
fprintf(stdout,"TCP Select Chat Server listen on %d\n",port);
FD_ZERO(&user_list);
while(1)
{
FD_ZERO(&fdset);
FD_SET(listen_fd,&fdset);
//把所有在线的socket加入到监听的集合中,每次循环都要重新加,
// 因为上一次的集合已经被select清空了
if(max_fd < listen_fd )
maxfd = (listen_fd +1);
else
maxfd = (max_fd +1) ;
printf("maxfd = %d,max_fd=%d,listen_fd=%d\n",maxfd,max_fd,listen_fd);
for(fd = 3 ; fd <= max_fd ; fd++)
{
if(FD_ISSET(fd,&user_list))
FD_SET(fd,&fdset);
}
//开始监听,等着客户端的请求
ret = select(maxfd,&fdset,NULL,NULL,NULL);
if(ret < 1)
continue;
//说明已经有socket接收数据,此时select会清空fdset,并把发现变化的socket重新放入fdset
if(FD_ISSET(listen_fd,&fdset)) //说明有客户端发来联接请求
{
memset(&client_addr,0,sizeof(client_addr));
client_addr.sin_family = AF_INET;
addr_len = sizeof(client_addr); //必须赋值!
printf("accept client ...\n");
client_fd = accept(listen_fd,(struct sockaddr *)&client_addr,&addr_len);
if(client_fd == -1)
{
perror("accept");
continue;
}
fprintf(stdout,"client socket %d,addr %s,port %d\n",client_fd,
inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port));
//把socket加入在线用户表
FD_SET(client_fd,&user_list);
if(client_fd > max_fd)
max_fd = client_fd;
}
else //说明客户端发来ECHO信息,用FD_ISSET查出是哪一个socket
{
printf("recv max_fd %d\n",max_fd);
for(fd = 3 ; fd <=max_fd ; fd++)
{
if(FD_ISSET(fd,&fdset))
{
process_fn(fd);
break;
}
}
}
}
printf("exit");
close(listen_fd);
}
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