如何基于c语言tftp服务器与客户端实现_华清远见

......如何基于c语言tftp服务器与客户端实现本篇文章主要的容就是教大家，如何基于c语言tftp服务器与客户端实现，是非常精彩的容，希望对大家的学习之路有所帮助。TFTP(TrivialFileTransferProtocol,简单文件传输)是TCP/IP协议族中的一个用来在客户机与服务器之间进行简单文件传输的协议，提供不复杂、开销不大的文件传输服务。端口号为69。开发环境：ubuntu所用知识点：c，socket,tcp/ip协议A)本实验主要实现tftp协议的服务器与客户端。服务器实现功能有：1)接收处理客户端请求，上传下下载文件2)进行用户验证3)对传输数据进行加密解密处理4)生成日志文件客户端实现功能有：1)向服务器发出请求，上传或下载文件2)对传输数据加密解密3)对用户信息进行MD5加密B)相关代码实现：宏定下：#ifndefMAKEWORD#defineMAKEWORD(l,h)((unsignedshort)(((unsignedchar)(l))|(((unsignedshort)(unsignedchar)(h))<<8)))#endif#defineWSA_MAJOR_VERSION1#defineWSA_MINOR_VERSION1#defineWSA_VERSIONMAKEWORD(WSA_MAJOR_VERSION,WSA_MINOR_VERSION)#defineTFTP_OCTET1#defineTFTP_WSTAT_FIRSTACK0#defineTFTP_WSTAT_NEXTACK1#defineTFTP_WSTAT_LASTACK2#defineTFTP_RRQ1//读请求#defineTFTP_WRQ2//写请求#defineTFTP_DATA3//数据#defineTFTP_ACK4//ACK#defineTFTP_ERROR5//Error#defineMAX_RETRY3//最大重复次数#defineTFTP_NOTEND_DATALEN512+2+2//数据块长度//错误种类#defineNot_defined0#defineFile_not_found1#defineAccess_violation2#defineDisk_full3#defineIllegal_TFTP_operation4#defineUnknown_port5#defineFile_already_exists6#defineNo_such_user7#defineTime_out8#defineRead_file_Error9#defineCannot_create_file10#definepasswd_or_user_error11包的填充：#include"define.h"#include#includeintmakeack(unsignedshortnum,char*buffer,intsize);intmakedata(unsignedshortnum,char*data,intdatasize,char*buffer,intbufsize);intmakeerr(unsignedshortnum,char*buffer);//ACK包填充intmakeack(unsignedshortnum,char*buffer,intsize){intpos=0;buffer[pos]=0;pos++;buffer[pos]=TFTP_ACK;//操作码为04pos++;buffer[pos]=(char)(num>>8);//块号2个字节pos++;buffer[pos]=(char)num;pos++;returnpos;}//Data包填充intmakedata(unsignedshortnum,char*data,intdatasize,char*buffer,intbufsize){intpos=0;buffer[pos]=0;pos++;buffer[pos]=TFTP_DATA;//操作码为03pos++;buffer[pos]=(char)(num>>8);//块号pos++;buffer[pos]=(char)num;pos++;memcpy(&buffer[pos],data,datasize);//填充数据pos=pos+datasize;returnpos;}//ERROR包填充intmakeerr(unsignedshortnum,char*buffer){intpos=0;buffer[pos]=0;pos++;buffer[pos]=TFTP_ERROR;//操作码为05pos++;buffer[pos]=(char)(num>>8);//错误种类号pos++;buffer[pos]=(char)num;pos++;returnpos;}日志log.c实现#includestaticcharlog[100];//日志chardatetime[20];//记录时间变量inttimeout=2,retran=3;//服务器参数voidrecord(inta,structsockaddr_in*sin,char*file){chartem[60];time_tt=time(0);//初始化日历时间strftime(datetime,sizeof(datetime),"%y/%m/%d%X",localtime(&t));//将时间格式化strcat(log,datetime);//将时间写入记录//将字符串格式化bzero(&tem,sizeof(tem));if(a==1)sprintf(tem,"收到来自%s上传文件%s的请求。\n",inet_ntoa(sin->sin_addr),file);if(a==2)sprintf(tem,"%s上传文件%s完毕。\n",inet_ntoa(sin->sin_addr),file);if(a==3)sprintf(tem,"收到来自%s下载文件%s的请求。\n",inet_ntoa(sin->sin_addr),file);if(a==4)sprintf(tem,"%s下载文件%s完毕。\n",inet_ntoa(sin->sin_addr),file);if(a==5)sprintf(tem,"出现出错，操作中断。\n",inet_ntoa(sin->sin_addr),file);//将具体信息写入记录strcat(log,tem);FILE*write;if((write=fopen("log.txt","a+"))==NULL)printf("打开记录文件失败\n");//将记录写入文件fwrite(&log,strlen(log),1,write);fclose(write);bzero(&log,sizeof(log));}加密解密实现#include#include#includeintdecrypt(FILE*in,FILE*out);intencrypt(FILE*in,FILE*out);unsignedcharatoh(char*hexstr);intencrypt(FILE*in,FILE*out){if(in==NULL||out==NULL){fprintf(stderr,"%s\n","fileerror!\n");return-1;}unsignedcharhex;while(fread(&hex,1,1,in)){hex=~hex^0x98;fprintf(out,"%02X",hex);}return0;}intdecrypt(FILE*in,FILE*out){if(in==NULL||out==NULL){fprintf(stderr,"%s\n","fileerror!");return-1;}unsignedcharhexstr[3];unsignedcharhex=0;inti=0;while(fread(hexstr,2,1,in)){hex=atoh(hexstr);hex=~(hex^0x98);fwrite(&hex,1,1,out);}return0;}/*convertstringtohex*/unsignedcharatoh(char*hexstr){inti;inthextodec[]={0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};charchtodec[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};unsignedcharhexnum=0;for(i=0;i65535)blocknum=0;//最后一包if(ret工程

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