client.c

最传统得加密解密方法des,此源代码需在嵌入式linux下编译运行

//-------------------POWERED BY BOBO-----------
//-------------------引入库函数--------------------
#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 "des.h"
//-------------------------------------------------
#define RECVBUFSIZE 1024	//定义接收数据缓冲区大小

void process(FILE *fp,int sockfd);
main(int argc, char *argv[])
{
    int fd;			//定义SOCKET参量
    struct hostent *he;
    struct sockaddr_in server;	//定义服务端SOCKERADDR结构
    int portnumber;		//定义端口号
    
    if(argc != 3)			//判断输入参数
    {
        fprintf(stderr, "Usage:%s hostname portnumber\a\n", argv[0]);
        exit(1);
    }

    if((portnumber=atoi(argv[2])) < 0)
    {
        fprintf(stderr,"Usage:%s hostname portnumber\a\n", argv[0]);
        exit(1);
    }
    
    if((fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)	//建立SOCKET
    {
        fprintf(stderr, "Socket Error:%s\a\n", strerror(errno));
        exit(1);
    }    
    bzero(&server, sizeof(server));			//设置SOCKADDR结构指向服务器
    server.sin_family = AF_INET;			
    server.sin_port = portnumber;
    server.sin_addr.s_addr = inet_addr(argv[1]);
    
    if(connect(fd, (struct sockaddr *)(&server), sizeof(struct sockaddr)) == -1)//同服务器建立连接
    {
        fprintf(stderr, "Connect Error:%s\a\n", strerror(errno));
        exit(1);
    }
    process(stdin,fd);				
    close(fd);
    //exit(0);
} 
void process(FILE *fp,int sockfd)
{
	char sendline[1024],recvline[1024];	//定义接收发送缓冲区
	char buf[1024];			//密文缓冲区
	char Key[8]="12345678";		//8位密钥
	int numbytes;			//定义接收数据长度
	printf("Connect to server!\n");
	while(fgets(sendline,1024,fp)!=NULL)
	{
		des_go(buf,sendline,strlen(sendline),Key,1);
		printf("%s\n",buf);
		send(sockfd,buf,strlen(buf),0);		//发送数据
		if((numbytes=recv(sockfd,recvline,1024,0))==0)	//接收数据
		{
			printf("Server Busy!\n");
			return;
		}
		recvline[numbytes]='\0';
		printf("Server's Back: %s",recvline);
		//close(sockfd);

	}
}