#include<myhead.h>
#define ERR_MSG(msg) do{\
fprintf(stderr, "__%d__:", __LINE__);\
perror(msg);\
}while(0)
#define SER_PORT 69
#define SER_IP "192.168.101.49"
int do_download(int cfd, struct sockaddr_in sin);
int main(int argc, const char *argv[])
{
//创建报式套接字文件
int cfd = socket(AF_INET, SOCK_DGRAM, 0);
if(cfd < 0)
{
ERR_MSG("socket");
return -1;
}
printf("socket create success cfd=%d\n", cfd);
//填充服务器的地址信息结构体,给dento函数使用
//真实的地址信息结构体根据地址族指定, AF_INET:man 7 IP
struct sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_port = htons(SER_PORT);
sin.sin_addr.s_addr = inet_addr(SER_IP);
char choose = 0;
while(1)
{
system("clear");
printf("-------------------------\n");
printf("--------1.下载-----------\n");
printf("--------2.上传-----------\n");
printf("--------3.退出-----------\n");
printf("-------------------------\n");
printf("请输入>>>");
scanf("%c", &choose);
while(getchar()!=10); //循环吸收垃圾字符
switch(choose)
{
case '1':
do_download(cfd, sin);
break;
case '2':
//do_upload
break;
case '3':
goto END;
break;
default:
printf("输入错误,请重新输入\n");
break;
}
printf("请输入任意字符清屏>>>");
while(getchar()!=10);
}
END:
//关闭套接字
close(cfd);
return 0;
}
int do_download(int cfd, struct sockaddr_in sin)
{
char buf[516] = "";
char filename[20] = "";
printf("请输入要下载的文件名>>>");
scanf("%c",filename);
while(getchar()!=10);
//组下载请求包,
unsigned short* ptr1 = (unsigned short*)buf;
*ptr1 = htons(1); //组操作码
char* ptr2 = buf+2;
strcpy(ptr2, filename); //组名字
char* ptr4 = ptr2+strlen(filename)+1;
strcpy(ptr4, "octet"); //组模式
int size = 2+strlen(ptr2)+1+strlen(ptr4)+1;
//发送下载请求 sendto
if(sendto(cfd, buf, size, 0, (struct sockaddr*)&sin, sizeof(sin)) < 0)
{
ERR_MSG("sendto");
return -1;
}
printf("sendto download request success\n");
unsigned short k = 0; //本地记录的块编号
int fd; //初始化文件描述符
socklen_t addrlen = sizeof(sin);
ssize_t res = 0;
while(1)
{
memset(buf, 0, sizeof(buf)); //清空
//接收数据 recvfrom, 接收地址信息
if((res = (recvfrom(cfd, buf, sizeof(buf), 0, (struct sockaddr*)&sin, &addrlen))) < 0)
{
ERR_MSG("recefrom");
return -1;
}
if(3 == buf[1])
{
//UDP会数据重复,防止重复收包
//记录传过来的块编号,判断每次编号是否正确
if(htons(k+1) == *(unsigned short*)(buf+2))
{
k++;
if((fd=open("01test.c",O_WRONLY|O_CREAT|O_TRUNC, 0664)) < 0)
{
ERR_MSG("open");
return -1;
}
}
//将获取到的文件写入文件中
if(write(fd, buf+4, res-4) < 0)
{
ERR_MSG("write");
return -1;
}
//组ACK sendto
buf[1] = 4;
if(sendto(cfd, buf, 4, 0, (struct sockaddr*)&sin, sizeof(sin)) < 0)
{
ERR_MSG("sendto");
return -1;
}
//判断数据是否小于512,若小于则下载完成
if(res-4 < 512)
{
printf("文件下载完成\n");
break;
}
}
//错误包
if(5 == buf[1])
{
printf("MSG_ERR: code[%d] msg[%s] __%d__\n",\
ntohs(*(unsigned short*)(buf+2)), buf+4, __LINE__);
break;
}
}
close(fd);
close(cfd);
return 0;
}
8.29网络编程作业
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转载自blog.csdn.net/JunCool02/article/details/132570058
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