- 论坛徽章:
- 0
|
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define MYPORT 69
char getfile[100]; //存放rrq请求
char data[600];//接收数据
int main(int argc, char *argv[])
{
char * file;//rrq请求指针
int getfilelen;
int sockfd;
int i;
int fromlen;
int len;
int sendlen;
FILE *fd;
char ack[4];//头部4个字节
struct sockaddr_in their_addr;
struct sockaddr_in from_addr;
struct hostent *he;
if (argc != 3)
{
fprintf(stderr,"usage: tftp hostname file\n");
exit(1);
}
//-----构造头部 加文件名加传输方式---------
getfile[0]=0;
getfile[1]=1;//表示rrq = 1 Read request请求读取远程系统
file =&getfile[2];
strcat(file,argv[2]);
getfilelen=strlen(argv[2])+2;
getfile[getfilelen]='\0';
file =&getfile[getfilelen+1];
strcat(file,"netascii");
getfilelen=2+strlen(argv[2])+1+strlen("netascii")+1;
getfile[getfilelen-1]='\0';
//printf("=======%d\n",getfilelen);
//-------------------------------------------------------
//for(i=0;ih_addr);
bzero(&(their_addr.sin_zero),8);
//向服务器发送请求
if ((sendlen=sendto(sockfd, getfile, getfilelen, 0, (struct sockaddr *)&their_addr, sizeof(struct sockaddr))) == -1)
{
perror("recvfrom");
exit(1);
}
//printf("sent %d bytes to %s\n",numbytes,inet_ntoa(their_addr.sin_addr));
//下面是接收数据部分
fromlen = sizeof(from_addr);
for(i=0;;i++)
{
len=recvfrom(sockfd, data, 600, 0,(struct sockaddr *)&from_addr, &fromlen);
//printf("data:\n%s\n",data);
//拷贝前面四个字节的头部用于返回时的ACK块号
memcpy(ack,data,4);
if(ack[1]==5)
{
printf("Error:");
if(ack[3]==0)
printf("no define\n");
else if(ack[3]==1)
printf("not found file\n");
else if(ack[3]==2)
printf("Could not open requested file for reading\n");
else if(ack[3]==3)
printf("disk full\n");
else if(ack[3]==4)
printf("error operation\n");
else if(ack[3]==5)
printf("unknown ID\n");
else if(ack[3]==6)
printf("file exeist\n");
else if(ack[3]==7)
printf("no such user\n");
else
printf("unknown\n");
goto out;
}
if(i==0)
{ //创建文件
fd = fopen(argv[2], "wb");
}
//第二个字节表示传送数据=3,加1表示ack
ack[1]++; //ACK包,操作码为4
//数据写入 文件
fwrite(data+4, sizeof(unsigned char), len-4, fd);
//这一步很关键,根据tftp协议需要向 服务器的发送数据端口回应ack
their_addr.sin_port = from_addr.sin_port;
if ((sendlen=sendto(sockfd,ack, sizeof(int), 0,(struct sockaddr *)&their_addr, sizeof(struct sockaddr))) == -1)
{
perror("recvfrom");
exit(1);
}
//printf("sent %d bytes to %s\n",numbytes,inet_ntoa(their_addr.sin_addr));
if(len
本文来自ChinaUnix博客,如果查看原文请点:http://blog.chinaunix.net/u1/33226/showart_507940.html |
|