UDP模拟FTP程序

程序使用

1.运行服务端 ./ftp_server 出现ftp>

输入 get filename1.txt (filename1.txt为接收文件的名字）

2.运行客户端，如果是本机 ./fpt 127.0.0.1,出现ftp>

输入 put filename2.txt （filename2.txt）为要发送的文件。

void get_cmd(char **p)
{
fgets(*p,100,stdin);
}
/*将带有空格的字符串s进行解析，存放到cmd字符串数组中*/
int split_string(char *s,char _cmd[][100])
{
char *p = s;
int i = 0;
int j = 0;
while(*p != '\n')
{
if(*p == ' ')
{
_cmd[i][j]='\0';
i++;
j = 0;
p++;
/*处理多个空格的情况*/
while(*p == ' ')
{
p++;
}
}
else
{
_cmd[i][j] = *p;
p++;
j++;
}
}
return i+1;
}

2.服务端ftp_server.c

/*
UDP 传输方式实现FTP，服务器段
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <sys/types.h>
#include "cmd.h"
int port = 8888;
int sockfd;
int bind_ret; /*绑定的返回值*/
//void get_cmd(char **p);/*从控制台获取命令*/
//int split_string(char *s,char _cmd[][100]); /*解析命令*/
struct sockaddr_in adr_inet;/*服务器端地址信息*/
void bind_ip();/*绑定服务器地址信息*/
void get_file(char *_filename);/*接受文件*/
int main()
{
char *s; /*从控制台获得的命令*/
char (*cmd)[100];/*分割后的命令*/
int len;/*参数个数*/
s = (char *)malloc(sizeof(char)*100);
cmd = (char (*)[])malloc(sizeof(s)*10);
bind_ip();
printf("ftp>");
get_cmd(&s);
split_string(s,cmd);
while(strcmp(cmd[0],"quit") != 0)
{
if(strcmp(cmd[0],"get") == 0)
{
char filename[100];
strcpy(filename,cmd[1]);
if(!fork())
{
get_file(filename);
exit(0);
}
}
get_cmd(&s);
len = split_string(s,cmd);
}
close(sockfd);
exit(0);
}
/*绑定服务器地址信息*/
void bind_ip()
{
/*建立IP地址*/
adr_inet.sin_family = AF_INET;
adr_inet.sin_port = htons(port);
adr_inet.sin_addr.s_addr = htonl(INADDR_ANY);
bzero(&(adr_inet.sin_zero),8);
/*建立socket*/
sockfd = socket(AF_INET,SOCK_DGRAM,0);
if(sockfd == -1)
{
perror("socket error!");
exit(1);
}
/*绑定socket*/
bind_ret = bind(sockfd,(struct sockaddr *)&adr_inet,sizeof(adr_inet));
if(bind_ret == -1)
{
perror("bind error!");
exit(1);
}
}
/*接受文件*/
void get_file(char *_filename)
{
int len;
char buf[256];
struct sockaddr_in adr_clnt;/*用来保存客户端地址信息*/
len = sizeof(adr_clnt);
/*创建一个文件，用来保存传送过来的文件*/
FILE *fp;
fp = fopen(_filename,"w+");
if(fp == NULL)
{
perror("create file error!");
exit(1);
}
printf("Waiting client to download!\n");
while(1)
{
/*接受传来的信息*/
bind_ret = recvfrom(sockfd,buf,sizeof(buf),0,(struct sockaddr*)&adr_clnt,&len);
if(bind_ret < 0)
{
perror("recvfrom error!");
exit(1);
}
buf[bind_ret] = '\0';
if(strncmp(buf,"stop",4) != 0)
{
//printf("receive :%s\n",buf);
fputs(buf,fp);
}
if(strncmp(buf,"stop",4) == 0)
{
printf("Finished!\n");
break;
}
}
close(fp);
printf("ftp>");
}

3.客户端ftp.c

/*
UDP 传输方式实现FTP,客户段
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>
#include <malloc.h>
#include "cmd.h"
int port = 8888;
int sockfd;/*套接字描述符*/
struct sockaddr_in adr_srvr;/*服务器地址信息*/
//void get_cmd(char **p);/*从控制台获取命令*/
int connect_to_server(char * ip);/*连接服务器*/
//int split_string(char *s,char _cmd[][100]); /*解析命令*/
void send_file(char *filename);/*发送文件*/
int main(int argc,char **argv)
{
connect_to_server(argv[1]);
//connect_to_server("127.0.0.1");
char *s; /*从控制台获得的命令*/
char (*cmd)[100];/*分割后的命令*/
int len;/*输入的参数个数*/
s = (char *)malloc(sizeof(char)*100);
cmd = (char (*)[])malloc(sizeof(s)*10);
printf("ftp>");
/*注意不能用get_cmd(s),因为p存放的不是“s存放的地址”，而是
s本身的地址。详细查看“彻底搞定C指针”的第4篇。
*/
get_cmd(&s);
len = split_string(s,cmd);
while(strcmp(cmd[0],"quit") != 0)
{
if(strcmp(cmd[0],"put") == 0)
{
char filename[100];
strcpy(filename,cmd[1]);
send_file(filename);
}
printf("ftp>");
get_cmd(&s);
len = split_string(s,cmd);
}
close(sockfd);
exit(0);
}
int connect_to_server(char * ip)
{
struct hostent *host;
printf("Connect to server……\n");
/*建立IP地址*/
host = gethostbyname(ip);
if(host == NULL)
{
herror("gethostbyname error!");
exit(1);
}
/*初始化服务器地址信息*/
adr_srvr.sin_family = AF_INET;
adr_srvr.sin_port = htons(port);
adr_srvr.sin_addr = *((struct in_addr *)host->h_addr);
bzero(&(adr_srvr.sin_zero),8);
/*建立socket*/
sockfd = socket(AF_INET,SOCK_DGRAM,0);
if(sockfd == -1)
{
perror("socket error!");
exit(1);
}
return 1;
}
void send_file(char *_filename)
{
FILE *fp;
int send_ret;
char buf[256];
char str1[80];
fp = fopen(_filename,"r");
if(fp == NULL)
{
perror("open failed!");
return ;
}
//读取数据传递给UDPserver
printf("Sending……\n");
while(fgets(str1,256,fp)!=NULL)
{
//printf("%s\n",str1);
sprintf(buf,"%s",str1);
send_ret = sendto(sockfd,buf,sizeof(buf),0,(struct sockaddr*)&adr_srvr,sizeof(adr_srvr));
if(send_ret < 0)
{
perror("sendto error!");
return;
}
}
printf("Finished!\n");
sprintf(buf,"stop\n");
send_ret = sendto(sockfd,buf,sizeof(buf),0,(struct sockaddr*)&adr_srvr,sizeof(adr_srvr));
if(send_ret < 0)
{
perror("sendto error!");
return ;
}
fclose(fp);
}

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UDP模拟FTP程序