基于UDP的tftp传输服务的客户端

下载前后

上传前后

代码

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

#define SER_PORT 69
#define SER_IP "192.168.124.116"

int do_download(int cfd, struct sockaddr_in sin)
{
	char filename[20] = "";
	printf("请输入要下载的文件名>>");
	scanf("%s",filename);
	while(getchar() != '\n');
	
	//组下载请求包
	char rq_buf[128] = "";
	short *p1 = (short*)rq_buf;
	*p1 = htons(1);         //操作码 下载为1

	char *p2 = rq_buf+2;
	strcpy(p2, filename);    //文件名

	char *p3 = p2+strlen(filename)+1;
	strcpy(p3, "octet");			//模式
	
	int rq_len = 2+strlen(p2)+1+strlen(p3)+1;
	
	//给服务器发送一个下载请求
	if( sendto( cfd, rq_buf, rq_len, 0, (struct sockaddr*)&sin, sizeof(sin) ) <0){
		fprintf( stderr, "line:__%d__", __LINE__);
		perror("sendto");
		return -1;
	}
	printf("sendto download 请求成功 __%d__\n",__LINE__);
	
	struct sockaddr_in cin;		//存储临时地址信息
	int addrlen = sizeof(cin);
	char tempbuf[516] = "";	
	
	for(int i=1; ;i++){
		memset( tempbuf, 0, 516);
		int res = recvfrom( cfd, tempbuf, sizeof(tempbuf), 0, (struct sockaddr*)&cin, &addrlen) ;		//接收数据包
		if(res <0){	
			fprintf(stderr, "__%d__", __LINE__);
			perror("recvform");
			break;
		}
		//判断报错+写文件
		short *data = (short*)tempbuf;
		short num = ntohs(*(data+1));
		char *wrt = tempbuf+4;

		
		if(3 == ntohs(*data) ){
			int fd = open(filename, O_CREAT|O_RDWR|O_APPEND, 0666);   //创建接收的文件
			if(fd <0){
				fprintf(stderr, "line:__%d__",__LINE__);
				perror("open");
				return -1;
			}
			int ret = write(fd, wrt, res-4);
			if(ret<0 || ret!=res-4){
				perror("write err");
				return -2;
			}
		    ret = close(fd);
			if(ret <0){
				perror("close err");
				return -2;
			}
		}
		else if(5 == ntohs(*data)){
			printf("Error message:%s\n",tempbuf+4);
			return -1;
		}
		else{ 
			printf("操作码 err\n");
			return -1;
		}
		//发回ACK
		char ack[4] = "";
		short *a1 = (short*)ack;
		*a1 = htons(4);
		short *a2 = a1+1;
		*a2 = htons(num);
		if( (sendto(cfd, ack, 4, 0, (struct sockaddr*)&cin, addrlen)) <0){
			fprintf(stderr, "__%d__",__LINE__);
			perror("sendto");
			return -1;
		}
		printf("sendto ack%d success__%d__\n",i,__LINE__);
		//若该数据包数据长度小于512，则结束
		if((res-4)<512){
			printf("传输结束\n");
			break;
		}
	}
	return 0;
}

int do_upload(int cfd, struct sockaddr_in sin)
{	
	char filename[20] = "";
	printf("请输入要上传的文件名>>");
	scanf("%s",filename);
	while(getchar() != '\n');
	
	//组上传请求包
	char rq_buf[128]="";
	short *p1 = (short*)rq_buf;
	*p1 = htons(2);         //操作码 上传为2

	char *p2 = rq_buf+2;
	strcpy(p2, filename);    //文件名

	char *p3 = p2+strlen(filename)+1;
	strcpy(p3, "octet");			//模式
	
	int rq_len = 2+strlen(p2)+1+strlen(p3)+1;
	//给服务器发送一个上传请求
	if(sendto(cfd, rq_buf, rq_len, 0,(struct sockaddr*)&sin, sizeof(sin)) <0){
		fprintf(stderr, "__%d__",__LINE__);
		perror("sendto");
		return -1;
	}
	printf("senfto upload 请求成功__%d__\n",__LINE__);
	
	struct sockaddr_in cin;		//存储临时地址信息
	int addrlen = sizeof(cin);
	char ack_buf[4];
	memset(ack_buf, 0, sizeof(ack_buf));
	//接收第一个ACK包
	int res = recvfrom(cfd, ack_buf, sizeof(ack_buf), 0, (struct sockaddr*)&cin, &addrlen);
	if(res <0){
		fprintf(stderr,"__%d__",__LINE__);
		perror("recvfrom");
		return -1;
	}
	short *ack_p1 = (short*)ack_buf;
	short *ack_p2 = ack_p1+1;
	printf("recv ack_bug success __%d__\n",__LINE__);
	
	if(4 != ntohs(*ack_p1) ){
		printf("操作码：%d  块编号：%d ;ack err",ntohs(*ack_p1),ntohs(*ack_p2));
		return -1;
	}
	printf("recv ack success __%d__\n",__LINE__);
	//开始发送数据包
	int fd = open(filename,O_RDONLY);
	if(fd <0){
		fprintf(stderr, "__%d__",__LINE__);
		perror("open");
		return -1;
	}
	char temp[516]="";
	//组合数据包
	short *data_p1 = (short*)temp;
	*data_p1 = ntohs(3);
	
	short *data_p2 = data_p1+1;
	*data_p2 = ntohs(0);
	
	char *data_p3 = (char*)p2+1;
	//循环获取文件内容，进行数据包组合
	for(int i=1; ; i++){
		memset(temp+4, 0, 512);
		*data_p2 = ntohs(i);
		int ret =read(fd, temp+4, 512);
		if(ret <0){
			perror("read");
			return -3;
		}
		if(sendto(cfd, temp, 516, 0, (struct sockaddr*)&cin, addrlen)<0){
			fprintf(stderr,"__%d__",__LINE__);
			perror("sendto");
			return -1;
		}
		printf("sendto upload %s databag success __%d__\n",filename,__LINE__);
		//清空ACK包并重新获取
		memset(ack_buf, 0, 4);
		res = recvfrom(cfd, ack_buf, sizeof(ack_buf), 0, (struct sockaddr*)&cin, &addrlen);
		if(res <0){
			fprintf(stderr, "__%d__",__LINE__);
			perror("recvfrom");
			return -1;
		}
		short *new_ack_p1 = (short*)ack_buf;
		short *new_ack_p2 = new_ack_p1+1;
		
		if(4 != ntohs(*new_ack_p1) && i-1 != ntohs(*new_ack_p2)){
			printf("操作码：%d  块编号：%d ;ack err\n",ntohs(*new_ack_p1),ntohs(*new_ack_p2));
			perror("ack err");
			return -1;
		}
		printf("recv ack_bug%d success __%d__\n",i,__LINE__);
		
		if(ret<512){
			printf("传输结束\n");
			if(close(cfd) <0){
				perror("close");
				return -2;
			}
			break;
		}
	}
	return 0;
}

int main(int argc, const char *argv[])
{
	//获取IP
	if(argc <2){
		printf("请输入要连接的IP：");
		return -1;
	}
	
	//创建报式套接字
	int cfd = socket(AF_INET, SOCK_DGRAM, 0);
	if(cfd <0){
		fprintf(stderr, "__%d__",__LINE__);
		perror("socket");
		return -1;
	}
	printf("socket success __%d__\n",__LINE__);
	
	//服务器的地址信息结构体--->port：69
	struct sockaddr_in sin;
	sin.sin_family        = AF_INET;
	sin.sin_port          = htons(69);
	sin.sin_addr.s_addr   = inet_addr(argv[1]);
	
	//程序界面
	int loop =1;
	int choose =0;
	while(loop){
		printf("------------------\n");
		printf("------1.下载------\n");
		printf("------2.上传------\n");
		printf("------3.退出------\n");
		printf("------------------\n");
		printf("请输入>>");
		scanf("%d",&choose);
		while(getchar() != '\n');
		
			switch(choose){
				case 1:
					do_download(cfd,sin);
					break;
				case 2:
					do_upload(cfd,sin);
					break;
				case 3:
					loop = 0;
					break;
				default :
					printf("输入错误，请重新输入\n");
			}
		}
	close(cfd);
	
	return 0;
}