server.c

linux下基于ssl安全套接字设计的一个聊天程序

#include <stdlib.h> 
#include <stdio.h> 
#include <errno.h> 
#include <string.h> 
#include <netdb.h> 
#include <sys/types.h> 
#include <netinet/in.h> 
#include <sys/socket.h> 
#include <fcntl.h>

typedef struct socket_list
{
	int socket;
	struct socket_list *next;		
}socket_list;

socket_list *gHead=NULL;

/**********************************************/
void make_socket_nonblocking(int skt)
{
    int flag;
    flag = fcntl(skt, F_GETFL, 0);
    fcntl(skt, F_SETFL, flag | O_NONBLOCK);
}

int main(int argc, char *argv[]) 
{ 
	int sockfd,new_fd; 
	struct sockaddr_in server_addr; 
	struct sockaddr_in client_addr; 
	int sin_size,portnumber,nbytes;  
	char buffer[1024]; 
	socket_list *p1,*p2;
  
	if(argc!=2) 
	{ 
		fprintf(stderr,"Usage:%s portnumber\a\n",argv[0]); 
		exit(1); 
	} 
	
	if((portnumber=atoi(argv[1]))<0) 
	{ 
		fprintf(stderr,"Usage:%s portnumber\a\n",argv[0]); 
		exit(1); 
	} 
	if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1) 
	{ 
		fprintf(stderr,"Socket error:%s\n\a",strerror(errno)); 
		exit(1); 
	} 
	
	bzero(&server_addr,sizeof(struct sockaddr_in)); 
	server_addr.sin_family=AF_INET; 
	server_addr.sin_addr.s_addr=htonl(INADDR_ANY); 
	server_addr.sin_port=htons(portnumber); 
	 
	if(bind(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr))==-1) 
	{ 
		fprintf(stderr,"Bind error:%s\n\a",strerror(errno)); 
		exit(1); 
	} 

	make_socket_nonblocking(sockfd);
	
	if(listen(sockfd,5)==-1) 
	{ 
		fprintf(stderr,"Listen error:%s\n\a",strerror(errno)); 
		exit(1); 
	} 
		
	while(1) 
	{ 	
		sin_size=sizeof(struct sockaddr_in); 
		if((new_fd=accept(sockfd,(struct sockaddr *)(&client_addr),&sin_size))>0) 
		{ 
			make_socket_nonblocking(new_fd);
			p1=(socket_list*)malloc(sizeof(socket_list));
			p1->socket=new_fd;
			//在链表头部插入
			p1->next=gHead;			
			gHead=p1;
			fprintf(stdout,"Server get connection from %s\n",inet_ntoa(client_addr.sin_addr)); 			
		}
		 
		p1=gHead;
	  while(p1)
	  {					
			if((nbytes=recv(p1->socket,buffer,1024,0))==-1) 
	    {	    	  
	        switch (errno) 
	        {
	            case EAGAIN:
	                    /* do nothing, no data to be read. */
	                break;
	            case EPIPE:     // connection broke
	            case ENOTCONN:      // shut down
	            case ECONNRESET:
	                break;
	            default:
	                fprintf(stderr,"problems reading from socket (%d)\n", errno);
	                break;
	        }
	    }	
	    else if(nbytes>0)// if readable and # of bytes is 0, then the client has shut down
	    {
				buffer[nbytes]='\0'; 	
				if(send(p1->socket,buffer,strlen(buffer),0)==-1) 
				{ 
					fprintf(stderr,"send Error:%s\n",strerror(errno)); 
					exit(1); 
				} 	    	
	    }
			p1=p1->next;
		}		 
	} 
	
	close(sockfd); 
	exit(0); 
}