tcp_select_svr.c

linux下的多个网络通讯的例子 可多参考下

#include <stdio.h>
#include <stdlib.h>
	
#include <os_defs.h>
	
#if __OS_TYPE__ == __OS_LINUX__	
	#include <signal.h>
#endif
#include <os_socket.h>

/* 
  服务器采用select来实现多路复用，只使用一个进程来完成所有处理
  软件开销较少
 */
 
 void usage()
  {
    printf("tcp_select_svr port\n");
  }

#define MAXSOCKFD 20
int main(int argc ,char * argv[])
{

    int port;

   OS_SOCKET new_fd,socket = INVALID_SOCKET;

   char msg[ ] ="Welcome to server!";


  /* 联接表,以socket fd 为下标，如果对应位为1,
      表示这一下对应socket是联接上*/
   int is_connected[MAXSOCKFD];
  char buffer[512];
   int fd,addr_len,len;
   struct sockaddr_in addr;
   


   fd_set readfds;
   
   
   	
   if(argc<2)
   	{
          usage();
	   exit(-1);
   	}
  
#if __OS_TYPE__ == __OS_LINUX__	
   /* 防止用户下线时，内核发送SIGPIPE消息，此消息默认把进程退出，因此突略这一信号*/
   signal(SIGPIPE,SIG_IGN); 
#endif  

   port = atoi(argv[1]);
   
   if((port <= 1024 ) || (port >65000))
   	{
   	   fprintf(stderr,"error port %s\n",argv[1]);
	   exit(-2);
   	}

   /* 清空所有联接*/
    for(fd=0;fd<MAXSOCKFD;fd++)
          is_connected[fd]=0;

    OS_SocketInit();
	
    if(OS_OpenTCPServer(&socket, port)!=OS_OK)
    	{
    	   fprintf(stderr,"create tcp file server failure on %d\n",port);
    	   exit(-3);
    	}
	
    printf("server waiting on port %d,listen socket =%d\n",port,socket); 
    while(1)
   	{
   	    FD_ZERO(&readfds);
           FD_SET(socket,&readfds);
           for(fd=0;fd<MAXSOCKFD;fd++)
		   	 if(is_connected[fd]) FD_SET(fd,&readfds);

	    if(select(MAXSOCKFD,&readfds,NULL,NULL,NULL)<0)
			continue;

	    /* 检查是哪一些socket收到包*/ 	
           for(fd=3;fd<MAXSOCKFD;fd++)
           	{
           	    if(!FD_ISSET(fd,&readfds))   
			continue;

		   if(fd == socket )
		   	{/* 是侦听socket,这意味着有客户申请联接*/
		   	    if((new_fd = accept (socket,(struct sockaddr *)&addr,(socklen_t*)&addr_len))!=SOCKET_ERROR)
		   	    	{
		   	    	  /* 发送欢迎信息*/
		   	    	   send(new_fd,msg,sizeof(msg),0);
				   /* 登记这一客户端*/
			          is_connected[new_fd] =1;	

				   printf("---client socket=%d (ip=%s:port=%d) connected\n",new_fd,inet_ntoa(addr.sin_addr),ntohs(addr.sin_port));
		   	    	}					
		   	}
		   else
		   	{ /* 普通客户端发来的聊天信息*/
		   	       if((len =recv(fd,buffer,sizeof(buffer),0))<0)
		   	       	{ /* 用户下线*/
		   	       	   is_connected[fd]=0;
					   OS_SocketClose(fd);
		   	       	}
				   else
				   	{
				   	   int wfd;
				   	   /* 把信息转发*/
					   for(wfd = 3;wfd<MAXSOCKFD;wfd++)
					   	{
					   	   if((wfd == socket) || (is_connected[wfd] == 0) || (wfd == fd))
						   	continue;

						   if(send(wfd,buffer,len,0) == SOCKET_ERROR)
						   	{
						   	    is_connected[wfd]=0;
							    OS_SocketClose(wfd);
						   	}
					   	}
					      
				   	}
				   
		   	}
           	}
	     	
	   	   
   	}


OS_SocketClose(socket);

OS_SocketClear();
   
}