0811练习

实现TFTP的客户端，上传文件到服务器

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>                             
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>

//打印错误新的宏函数
#define ERR_MSG(msg)  do{\
    fprintf(stderr, " __%d__ ", __LINE__);\
    perror(msg);\
}while(0)        

#define N 516
#define PORT 69              //1024~49151
#define IP  "192.168.31.143"    //本机IP,用ifconfig查看


int main(int argc, const char *argv[])
{
	//创建报式套接字
	int sfd = socket(AF_INET, SOCK_DGRAM, 0);
	if(sfd < 0)
	{
		ERR_MSG("socket");
		return -1;
	}

	//填充服务器的IP地址及端口
	struct sockaddr_in sin;	
	sin.sin_family      = AF_INET;
	sin.sin_port        = htons(PORT);
	sin.sin_addr.s_addr = inet_addr(IP);

	//请求包
	char buf[N]="";
	char filename[20] = "";
	printf("请输入要上传的文件名>>>");
	fgets(filename, 20, stdin);
	filename[strlen(filename)-1] = 0;
	int size=sprintf(buf,"%c%c%s%c%s%c",0,2,filename,0,"octet",0);
	
	//发送读写请求
	if(sendto(sfd,buf,size,0, (struct sockaddr*)&sin, sizeof(sin))<0)
	{
		ERR_MSG("sendto");
		return -1;
	}
	printf("send success\n");


	//创建需要上传的文件
	int fd=open(filename,O_RDONLY);
	if(fd<0)
	{
		ERR_MSG("open");
		return -1;
	}
	printf("open success\n");
	
	unsigned short number=0;//块编号或差错码
	socklen_t addrlen = sizeof(sin);	

	while(1)
	{
		//接收ACK包
		bzero(buf,N);

		int len=recvfrom(sfd,buf,sizeof(buf),0,(struct sockaddr*)&sin,&addrlen);
		if(len<0)
		{

			ERR_MSG("recvfrom");
			return -1;
		}
		printf("rcv success\n");
	
		if(4==buf[1])
		{
			if(number==ntohs(*(unsigned short*)(buf+2)))
			{
				buf[1]=3;
				number++;
				*(unsigned short*)(buf+2)=htons(number);
				int res=read(fd,buf+4,N-4);
				if(res<0)
				{
					ERR_MSG("read");
					return -1;
				}
				else if(0==res)
				{
					printf("文件读取完毕\n");
					break;
				}
				if(sendto(sfd,buf,res+4,0, (struct sockaddr*)&sin, sizeof(sin))<0)
				{
					ERR_MSG("sendto");
					return -1;
				}
				printf("文件上传完毕\n");
			}
			else 
			{
				printf("文件上传失败\n");
				break;
			}

		}
		else if(5==buf[1])
		{
			printf("错误消息为[%s]\n",buf+4);
			break;
		}
	}
	
	close(sfd);


	return 0;

}