用udp实现tftp下载和上传功能

#include <myhead.h>
#define PORT 69
#define IP "192.168.122.24"
int shangchuan(int sfd,struct sockaddr_in sin,socklen_t socklen)
{int cfd=-1;if((cfd=open("./01udpk.c",O_RDONLY))==-1){perror("open error");return -1;}char rbuf[516]="";short a=1;int SIZE=sprintf(rbuf,"%c%c%s%c%s%c",0,2,"./01udpk.c",0,"octet",0);sendto(sfd,rbuf,SIZE,0,(struct sockaddr*)&sin,sizeof(sin));while(1){recvfrom(sfd,rbuf,sizeof(rbuf),0,(struct sockaddr*)&sin,&socklen);bzero(rbuf,sizeof(rbuf));int sre=read(cfd,rbuf+4,512);if(sre==0){break;}short *a1=(short*)rbuf;*a1=htons(3);short *a2=(short*)(rbuf+2);*a2=htons(a++);sendto(sfd,rbuf,sre+4,0,(struct sockaddr*)&sin,sizeof(sin));}close(cfd);
}
int xiazai(int sfd,struct sockaddr_in sin,socklen_t socklen)
{int fd=-1;if((fd=open("./helltaker.bmp",O_WRONLY|O_CREAT|O_TRUNC,0664))==-1){perror("open error");return -1;}char buf[516]="";char ack[4]="";int len=sprintf(buf,"%c%c%s%c%s%c",0,1,"./helltaker.bmp",0,"octet",0);sendto(sfd,buf,len,0,(struct sockaddr*)&sin,sizeof(sin));while(1){bzero(buf,sizeof(buf));int res=recvfrom(sfd,buf,sizeof(buf),0,(struct sockaddr*)&sin,&socklen);if(res<516){write(fd,buf+4,res-4);break;}write(fd,buf+4,res-4);short *q1=(short *)(buf+2);short *p4=(short *)ack;*p4=htons(4);short *p5=(short *)(ack+2);*p5=*q1;sendto(sfd,ack,4,0,(struct sockaddr*)&sin,sizeof(sin));}printf("下载完成\n");close(fd);}
int main(int argc, const char *argv[])
{int sfd=-1;if((sfd=socket(AF_INET,SOCK_DGRAM,0))==-1){perror("socket error");return -1;}int reuse=-1;if(setsockopt(sfd,SOL_SOCKET,SO_REUSEADDR,&reuse,sizeof(reuse))==-1){perror("setsockopt error");return -1;}struct sockaddr_in sin;sin.sin_family=AF_INET;sin.sin_port=htons(PORT);sin.sin_addr.s_addr=inet_addr(IP);socklen_t socklen=sizeof(sin);int num;while(1){printf("\t\t=======1.下载=======\n");printf("\t\t=======2.上传=======\n");printf("\t\t=======3.退出=======\n");printf("请输入功能:");scanf("%d",&num);while(getchar()!='\n');switch(num){case 1:{xiazai(sfd,sin,socklen);}break;case 2:{shangchuan(sfd,sin,socklen);}break;case 3 :goto END;default:printf("输入有误，请重新输入\n");}printf("按任意键清屏\n");while(getchar()!='\n');system("clear");}
END:close(sfd);return 0;
}