23111 网络编程 day4

思维导图

#include
#define SER_PORT 69
#define SER_IP "192.168.125.180"

int do_download(int cfd,struct sockaddr_in sin)
{
	//向服务器发送下载请求
	char buf[516]="";

	char fileName[40]="";

	printf("请输入文件名：");
	scanf("%s",fileName);
	getchar();

	//组装请求数据
	short *p1=(short*)buf;
	*p1=htons(1);

	char *p2=buf+2;
	strcpy(p2,fileName);

	char *p3=p2+strlen(p2)+1;
	strcpy(p3,"octet");

	int len=4+strlen(p2)+strlen(p3);  //要发送的长度

	//向服务器发送请求
	if(sendto(cfd,buf,len,0,(struct sockaddr*)&sin,sizeof(sin))==-1)
	{
		perror("sendto error");
		return -1;
	}
	printf("下载成功\n");

}

int do_upload(int sfd,struct sockaddr_in sin)
{
	char fileName[20]="";
	printf("请输入要上传的文件名>>>");
	fgets(fileName,20,stdin);
	fileName[strlen(fileName)-1]=0;

	//判断文件是否存在
	int fd=open(fileName,O_RDONLY);
	if(fd<0)
	{
		if(errno==ENOENT)
		{
			printf("文件不存在，请重新输入\n");
			return -2;
		}
		else
		{
			perror("open error");
			return -1;
		}
	}

	//上传请求
	char buf[516]="";
	int size=sprintf(buf,"%c%c%s%c%s%c",0,2,fileName,0,"octet",0);

	if(sendto(sfd,buf,size,0,(struct sockaddr*)&sin,sizeof(sin))<0)
	{
		perror("sendto error");
		return -1;
	}

	//循环接收发送的数据包
	int recv_len;
	unsigned short num=0;
	socklen_t addrlen=sizeof(sin);
	while(1)
	{
		bzero(buf,sizeof(buf));

		if(recvfrom(sfd,buf,sizeof(buf),0,(struct sockaddr*)&sin,&addrlen)==-1)
		{
			perror("recvfrom error");
			return -1;
		}
		
		if(buf[1]==4)
		{
			if(num==ntohs(*(unsigned short*)(buf+2)))
			{
				buf[1]=3;

				num++;
				*(unsigned short*)(buf+2)=htons(num);

				//读取数据
				int res=read(fd,buf+4,512);
				if(res<0)
				{
					perror("res error");
					return -1;
				}
				else if(res==0)
				{
					printf("文件上传成功\n");
					break;
				}
			}
			else
			{
				printf("文件上传失败\n");
				break;
			}
		}
		else if(buf[1]==5)
		{
			printf("----ERROR:%s----\n",buf+4);
			break;
		}

	}
	return 0;
}

int main(int argc, const char *argv[])
{
	if(argc<2)
{
		printf("input error\n");
		printf("usage:./a.out ip\n");
		return -1;
	}


	//1、创建套接字
	int cfd=socket(AF_INET,SOCK_DGRAM,0);
	if(cfd==-1)
	{
		perror("socket error");
		return -1;
	}

	//2、绑定端口号和IP地址
	//3、设置监听
	//服务器的地址信息
	struct sockaddr_in sin;
	sin.sin_family=AF_INET;
	sin.sin_port=htons(SER_PORT);
	sin.sin_addr.s_addr=inet_addr(argv[1]);

	//选项清单
	int mune=-1;
	while(1)
	{
		system("clear"); 
		printf("菜单选项如下：\n");
        printf("\t\t======1、下载=======\n");
        printf("\t\t======2、上传=======\n");
        printf("\t\t======0、退出=======\n");

		printf("请输入功能>>>");
		scanf("%d",&mune);
		getchar();

		switch(mune)
		{
		case 1:
			{
				//下载功能
				do_download(cfd,sin);
			}
			break;
		case 2:
			{
				//上传功能
				do_upload(cfd,sin);
			}
			break;
		case 0:
			goto END;
		default:printf("输入有误，请重新输入\n");
		}

		printf("请输入任意键，按回车清空\n");
		while(getchar()!='\n');	
	}


END:
	close(cfd);

	return 0;
}