网络编程TFTP上传作业

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

#define MSG_ERR(msg)do{\
	fprintf(stderr,"line:%d",__LINE__);\
	perror(msg);\
	return -1;\
}while(0)

#define PORT 69//端口号
#define IP "192.168.8.130"

int main(int argc, const char *argv[])
{
	//创建套接字
	int sfd = socket(AF_INET,SOCK_DGRAM,0);
	if(sfd<0)
		MSG_ERR("socket");

	//服务器的IP和端口
	struct sockaddr_in sin;
	sin.sin_family=AF_INET;//IPV4
	sin.sin_port=htons(PORT);//端口
	sin.sin_addr.s_addr=inet_addr(IP);//IP

	char wribuf[128]="";
	unsigned short* pa=(unsigned short*)&wribuf;
	*pa=htons(2);//操作码：2
	char *pb=wribuf+2;
	strcpy(pb,argv[1]);//文件名：argv[1]
	char *pc=pb+strlen(pb);//偏移位置
	*pc=0;//0
	char *pd=pc+1;
	strcpy(pd,"octet");//模式
	int size;
	size=2+strlen(pb)+1+strlen(pd)+1;//大小

	//向服务器发送写请求
	if(sendto(sfd,wribuf,size,0,(struct sockaddr*)&sin,sizeof(sin))<0)
		MSG_ERR("sendto");

	struct sockaddr_in cin;
	//cin.sin_family=AF_INET;
	//cin.sin_addr.s_addr = inet_addr(IP);

	size=sizeof(cin);

	char buf[128]="";
	//在当前目录下打开文件
	strcat(buf,"./");
	//命令行读取参数
	strcat(buf,argv[1]);
	//以读写方式打开
	int fd=open(buf,O_RDONLY,0666);
	if(fd<0)
		MSG_ERR("open");

	char databuf[600]="";
	unsigned short b=1;

	ssize_t res2=0;
	ssize_t res=0;
	char buf1[128]="";
	while(1)
	{
		bzero(databuf,sizeof(databuf));
		if(recvfrom(sfd,buf1,sizeof(buf1),0,(struct sockaddr*)&cin,&size)<0)
			MSG_ERR("recvfrom");

		res=read(fd,databuf+4,512);
		if(res<0)
			MSG_ERR("read");
		printf("%ld\n",res);
		
		*(unsigned short int*)databuf=htons(3);
		*(unsigned short int *)(databuf+2)=htons(b);
		res2=sendto(sfd,databuf,res+4,0,(struct sockaddr*)&cin,sizeof(cin));
		if(res2<0)
			MSG_ERR("sendto");
		printf("%ld----\n",res2);
		b++;
		if(res<512)
		{
			printf("数据上传完毕\n");
			break;
		}

	}
	close(sfd);
	close(fd);


	return 0;
}