socketfun.c

网络编程的服务端和客户端.包括用fork和select分别实现多进程编程和多线程编程.程序已经通过测试的.

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <netdb.h>
#include <netinet/in.h>


#include "err_exit.h"
#include "socketfun.h"

/* 创建和命名文件套接字 */
int make_named_socket(const char * filename)
{
	struct sockaddr_un name;
	int sock;
	size_t size;
	
	memset(&name,0,sizeof(struct sockaddr_un));
	/* 创建套接字 */
	sock=socket(AF_UNIX,SOCK_DGRAM,0);
	if(sock<0)
		err_exit("socket");
		
	/* 命名套接字 */
	name.sun_family=AF_UNIX;
	strcpy(name.sun_path,filename);
	
	/* 地十的大小是文件名开始听偏移与其长度之和加1（用于终止的空字节）*/
	/* size=sizeof(struct sockaddr_un)+1; */
	size=sizeof(struct sockaddr_un);
	if(bind(sock,(struct sockaddr *)&name,size)<0)
		err_exit("bind");
	return sock;
}
/* 命名一个Internet套接字地址 */
void init_sockaddr(struct sockaddr_in * name,const char * hostname,const char *serv)
{
	struct hostent *hp;
	char *host,myname[255];
	
	if(hostname==NULL){
		gethostname(myname,sizeof(myname));
		host=myname;
	}else{
		host=(char *)hostname;
	}
	
	/* 获取主机地址信息 */
	if((hp=gethostbyname(host))==NULL){
		printf("Unknown host:%s\n",host);
		exit(-1);
	}
	
	/* 填入服务器的IP地址和端口 */
	bzero(name,sizeof(struct sockaddr));
	/*printf("AF_INET=%d\n",AF_INET);*/
	if(hp->h_addrtype==AF_INET){
		name->sin_family=AF_INET;
		bcopy(hp->h_addr_list[0],&name->sin_addr,hp->h_length);
		if(serv==NULL)
			name->sin_port=htons(0);
		else
			name->sin_port=htons(atoi(serv));
	}else{
		printf("Unknown address type\n");
		exit(-1);
	}
}

int make_socket(unsigned short int port)
{
	int sock;
	struct sockaddr_in name;
	
	/* 创建套接字 */
	sock=socket(AF_INET,SOCK_STREAM,0);
	if(sock<0)
		err_exit("socket");
	
	/* 命名套接字 */
	name.sin_family=AF_INET;
	name.sin_port=htons(port);
	name.sin_addr.s_addr=htonl(INADDR_ANY);
	/*name.sin_addr.s_addr=inet_addr("192.168.1.68");*/
	/*bzero(&name.sin_zero,8);*/
	if(bind(sock,(struct sockaddr *)&name,sizeof(struct sockaddr_in))<0)
		err_exit("bind");
	return sock;	
}
int socket_connect(const char *hostname,const char *serv_port)
{
	int sockfd;
	struct sockaddr_in sockaddr;
	struct hostent *hp;
	char *host,myname[MAXNAMELEN];
	
	/* 初始化服务的IP地址和端口 */
	init_sockaddr(&sockaddr,hostname,serv_port);		
	
	/* 创建套接字 */
	if((sockfd=socket(AF_INET,SOCK_STREAM,0))<0)
		err_exit("socket error");
	
	/* 建立与服务的连接 */
	if(connect(sockfd,(struct sockaddr *)&sockaddr,sizeof(sockaddr))<0)
		err_exit("connect error");
	
	return(sockfd);
}
int socket_listen(const char *hostname,const char *server)
{
	int sockfd;
	struct sockaddr_in name;
	
	/* 创建套接字 */
	if((sockfd=socket(AF_INET,SOCK_STREAM,0))<0)
		err_exit("socket error");
		
	/* 初始套接字地址结构 */
	init_sockaddr(&name,hostname,server);
	if(bind(sockfd,(struct sockaddr *)&name,sizeof(name))<0)
		err_exit("bind");
		
	/* 创建侦听队列 */
	listen(sockfd,LISTENQ);
	return sockfd;
}
/*
int check_per(int sockfd,in_addr_t *refuselist)
{
	socklen_t len;
	struct sockaddr_in addr,raddr;
	in_addr_t s_addr;
	
	/* 查看与我连接的是谁 *//*
	len=sizeof(raddr);
	if(getpeername(sockfd,(struct sockaddr *)&raddr,&len)<0){
		printf("getpeername with socket %d failed \n",sockfd);
		return -1;
	}
	
	/* 拒绝来自特定地址的连接 *//*
	s_addr=raddr.sin_addr.s_addr;
	ap=refuse_addr_list;
	for(;ap!=0;ap+=){
		close(sockfd);
		return -1;
	}
	return 0;
}
*/