网络编程day03（UDP中的connect函数、tftp）

今日任务：tftp的文件上传下载（服务端已经准备好）

服务端（已上传）

 客户端：

代码：

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <strings.h>
#include <fcntl.h>//自定义报错提示
#define ERR_MSG(msg) do{\fprintf(stderr,"__%d__",__LINE__);\perror(msg);\
}while(0)//#define SER_PORT 69
//#define SER_IP "192.168.125.74"
#define SER_PORT 69
#define SER_IP "192.168.125.225"
int do_upload(int cfd,struct sockaddr_in addr);
int do_download(int cfd,struct sockaddr_in addr);
int main(int argc, const char *argv[])
{//1.创建socket套接字int cfd=socket(AF_INET,SOCK_DGRAM,0);if(cfd<0){ERR_MSG("socket");return -1;}puts("socket success");//3.接受和发送消息//目标地址信息struct sockaddr_in addr;addr.sin_family=AF_INET;addr.sin_port=htons(SER_PORT);addr.sin_addr.s_addr=inet_addr(SER_IP);socklen_t addrlen=sizeof(addr);//记录接受信息的目标地址信息struct sockaddr_in recv_addr;socklen_t recv_addrlen=sizeof(recv_addr);while(1){puts("---------------------------------");puts("------------1.上传---------------");puts("------------2.下载---------------");puts("------------3.退出---------------");puts("---------------------------------");puts("请选择>>");char choice;choice=getchar();while(getchar()!='\n');//循环吸收垃圾字符switch(choice){case '1':do_upload(cfd,addr);break;case '2':puts("download");do_download(cfd,addr);break;case '3':goto END;}}
END:/*char buf[128];while(1){printf("请输入>>>");fgets(buf,sizeof(buf),stdin);buf[strlen(buf)-1]='\0';int send_res=sendto(cfd,buf,sizeof(buf),0,(struct sockaddr*)&addr,addrlen);if(send_res<0){ERR_MSG("sendto");return -1;}puts("sendto success");if(strcmp(buf,"quit")==0)break;bzero(buf,sizeof(buf));int recv_res=recvfrom(cfd,buf,sizeof(buf),0,(struct sockaddr*)&recv_addr,&recv_addrlen);if(recv_res<0){ERR_MSG("recvfrom");return -1;}puts("recvfrom success");printf("[%s:%d]:%s\n",inet_ntoa(recv_addr.sin_addr),ntohs(recv_addr.sin_port),buf);	}*///4.关闭close(cfd);return 0;
}
int do_upload(int cfd,struct sockaddr_in addr){printf("请输入要上传的文件名.>>>");char name[20]="";scanf("%s",name);while(getchar()!=10);//组下载协议char buf[516]="";//操作码unsigned short *p1=(unsigned short*)buf;*p1=htons(2);//文件名char *p2=buf+2;strcpy(p2,name);//0//模式char *p4=p2+strlen(name)+1;strcpy(p4,"octet");//0int size=2+strlen(name)+1+strlen(p4)+1;//printf("buf==%s;size==%d",buf,size);//发送协议给服务器if(sendto(cfd,buf,size,0,(struct sockaddr*)&addr,sizeof(addr))<0){ERR_MSG("sendto");return -1;}puts("send upload protocal success");//打开一个文件，输入int fd=open(name,O_RDONLY);if(open<0){ERR_MSG("open");return -1;}unsigned short bNum=1;//重新定义一个地址的结构体，接受服务端传来的临时地址struct sockaddr_in dest_addr;socklen_t addrlen=sizeof(dest_addr);if(recvfrom(cfd,buf,sizeof(buf),0,(struct sockaddr*)&dest_addr,&addrlen)<0){ERR_MSG("recvfrom");return -1;}while(1){//组包:操作码+块编号+数据bzero(buf,sizeof(buf));unsigned short *opNum=(unsigned short*)buf;*opNum=htons(3);unsigned short *blockNum=opNum+1;*blockNum=htons(bNum);char* msg=buf+4;int read_res=read(fd,msg,512);if(read<0){ERR_MSG("read");}//发包ssize_t sendto_res=sendto(cfd,buf,sizeof(buf),0,(struct sockaddr*)&dest_addr,addrlen);if(sendto_res<0){ERR_MSG("sendto");return -1;}printf("sendto_res=%ld\n----",sendto_res);//接受ackif(recvfrom(cfd,buf,sizeof(buf),0,(struct sockaddr*)&dest_addr,&addrlen)<0){ERR_MSG("recvfrom");return -1;}opNum=(unsigned short*)buf;blockNum=opNum+1;if(ntohs(*opNum)==5){puts("操作码错误");printf("%d %d:%s",ntohs(*opNum),ntohs(*blockNum),msg);}else if(ntohs(*opNum)==4){if(ntohs(*blockNum)==bNum){puts("ACK correct");}else{puts("ACK incorrect");return -1;}}bNum++;if(read_res<512){printf("bNUm==%d\n",bNum);puts("upload done");break;}}close(fd);}
int do_download(int cfd,struct sockaddr_in addr){printf("请输入要下载的文件名.>>>");char name[20]="";scanf("%s",name);while(getchar()!=10);//组下载协议char buf[516]="";//操作码unsigned short *p1=(unsigned short*)buf;*p1=htons(1);//文件名char *p2=buf+2;strcpy(p2,name);//0//模式char *p4=p2+strlen(name)+1;strcpy(p4,"octet");//0int size=2+strlen(name)+1+strlen(p4)+1;//printf("buf==%s;size==%d",buf,size);//发送协议给服务器if(sendto(cfd,buf,size,0,(struct sockaddr*)&addr,sizeof(addr))<0){ERR_MSG("sendto");return -1;}puts("send download protocal success");//新建打开一个文件，等下写入int fd=open(name,O_WRONLY|O_CREAT|O_TRUNC,0664);if(fd<0){ERR_MSG("open");return -1;}//重新定义一个地址的结构体，接受服务端传来的临时地址struct sockaddr_in dest_addr;socklen_t addrlen=sizeof(dest_addr);while(1){//接受数据包int recv_res=recvfrom(cfd,buf,sizeof(buf),0,(struct sockaddr*)&dest_addr,&addrlen);if(recv_res<0){ERR_MSG("recvfrom");return -1;}unsigned short* opNum=(unsigned short*)buf;unsigned short* blockNum=opNum+1;char * msg=(char *)(blockNum+1);if(ntohs(*opNum)==5){puts("操作码错误");printf("%d %d:%s",ntohs(*opNum),ntohs(*blockNum),msg);}else if(ntohs(*opNum)==3){int wr_res=write(fd,msg,recv_res-4);if(wr_res<0){ERR_MSG("write");}else if(wr_res<512){puts("recvfrom done");break;}}//组ACK包,吾把buf当做ack来使*opNum=htons(4);//回复ACK包sendto(cfd,buf,4,0,(struct sockaddr*)&dest_addr,addrlen);bzero(buf,sizeof(buf));}//
}

运行结果：

不知道是网络的问题还是代码的问题，上传很慢，代码很快正常运行结束了，但是tftp服务端下载到win上很慢，7kb的也要5s以上

今日思维导图