function.c

linux网络编程 客户端 可以清除缓存

					//printf("lastline=2\n");
				}
				else
					lastline=0;
			}
			if(lastline==0 && reply_buf[i]==c_reply_code[0])
			{
				lastline=1;
				//printf("lastline=1\n");
			}
		}  //end for
		if(flag==1)
			break;
		else
			reply_length=read(sockfd, reply_buf, REPLY_BUFFER_SIZE-2);
	}
	return reply_code;
}
//-------------------------------------------------------------------------------------------------
int send_cmd(char *cmd, char *para, int sockfd) //从已经连接的sockfd中发送命令和参数 函数返回实际发送的字节数
{
	int send_length;
	if(cmd)
	{
		strcpy(send_buf, cmd);
		if(para)
		{
			strcat(send_buf,para);
			strcat(send_buf,"\r\n");
		}
		else
			strcat(send_buf,"\r\n");
		cmd_length=strlen(send_buf);
		printf("%s",send_buf);   //把要发出的命令输出
		send_length=write(sockfd, send_buf, cmd_length);
		if(send_length<0)
		{
			printf("Send error.\n");
		}
		return send_length;
	}
	return -1;
}
//-------------------------------------------------------------------------------------------------
int get_data(int in, int out)
{
	int new_sockfd = in;
	if(passive == 0) //PORT
	{
		new_sockfd = port_accept(in);
		if(new_sockfd<0)
		{
			return -1;
		}
	}
	while(1)
	{
		data_length=read(new_sockfd, data_buf, DATA_BUFFER_SIZE);
		if(data_length<=0)
			break;
		else
			write(out, data_buf, data_length);
	}
	if(passive == 0)
		close(new_sockfd);
	return 0;
}

//-------------------------------------------------------------------------------------------------
int cmd_format(char *cmd)  //将cmd整理。 返回参数的个数（包括命令本身）
{
	int num=0;
	int i=0, j=0;

	for(i=0;cmd[i]!='\n';i++)
	{
		if(cmd[i]!=' ')
		{	
			if(i==0)
				num++;
			if(i!=0 && cmd[i-1]==' ')
			{
				cmd[j]=' ';
				j++;
				num++;
			}
			cmd[j]=cmd[i];
			j++;
		}
	}
	cmd[j]='\0';
	return num;
}

//-------------------------------------------------------------------------------------------------
char *my_itoa(int i)
{
	char *a=malloc(42);  //enough for a 128 bit integer
	if(a)
		sprintf(a,"%d",i);
	return a;
}

//-------------------------------------------------------------------------------------------------
int get_ip(char *ip)   // include <ioctl.h>
{
	int   sock;  
  	struct   sockaddr_in   sin;  
  	struct   ifreq   ifr;  
   
  	sock=socket(AF_INET,SOCK_DGRAM,0);  
  	if(sock==-1)  
  	{	 
  		perror("socket");  
  		return -1; 
  	}  
   
  	strncpy(ifr.ifr_name,   ETH_NAME,   IFNAMSIZ);  
  	ifr.ifr_name[IFNAMSIZ-1]=0;  
   
  	if(ioctl(sock,SIOCGIFADDR,&ifr)<0)  
  	{  
  		perror("ioctl");  
  		return -1; 
  	}  
   
  	memcpy(&sin,   &ifr.ifr_addr,   sizeof(sin));  
  	//fprintf(stdout,"eth0:   %s\n",inet_ntoa(sin.sin_addr));  
   
   	ip=strcpy(ip, inet_ntoa(sin.sin_addr));
  	return 0;
}
//-------------------------------------------------------------------------------------------------
int rand_local_port()
{
	int port;
	srand((unsigned)time(NULL));
	port = rand() % 40000 + 1025;
	return port;
}
//-------------------------------------------------------------------------------------------------
int create_datasock()
{
	if(passive==1)  //pasv  先发送pasv命令到服务器，然后建立一个数据sockfd和收到的地址连接上去。
	{
		char *temp;
		int data_port;
		int client_data_sockfd;
		// 向服务器发送pasv 获取服务器的数据端口号 保存在data_port
		send_cmd("PASV",NULL, client_sockfd); //进入被动模式

		//reply_length=recv(client_sockfd, reply_buf, REPLY_BUFFER_SIZE,0);
		reply_length=get_reply(client_sockfd);

		if(reply_length<0)
			return 0;
		reply_buf[reply_length]='\0';
		if(atoi(reply_buf)==227)  //说明进入了被动模式
		{
			temp=strrchr(reply_buf,','); //strrchr()函数的作用是：查找一个字符串在另一个字符串中末次出现的位置.
			data_port=atoi(temp+1);
			*temp='\0';   
			temp=strrchr(reply_buf,',');
			data_port+=atoi(temp+1)*256;
		}

		//printf("data_port: %d", data_port);

		//将server_addr的端口号改成数据端口号
		if(data_port!=0)
			server_addr.sin_port=htons(data_port);
		//新建一个client_data_sockfd和server_addr连接connect
		client_data_sockfd=socket(AF_INET,SOCK_STREAM,0);
		if(client_data_sockfd<0)
		{
			printf("create client_data_sockfd failed.");
			return -1;
		}
		if(connect(client_data_sockfd,(struct sockaddr *)&server_addr,sizeof(server_addr))<0)
		{
			printf("cannot connect to the server: %s, port:%d\n",inet_ntoa(server_addr.sin_addr),ntohs(server_addr.sin_port));
			close(client_data_sockfd);
			return -1;
		}
		return client_data_sockfd;
	}  //end if(passive==1)

	else   //port  客户端设定一个数据端口，然后建立一个数据socket和该端口绑定，然后给服务器发送port命令 该命令包含客户端接受数据的端口。
	{
		//建立一个数据socket
		int client_data_sockfd;
		int i;
		client_data_sockfd=socket(AF_INET,SOCK_STREAM,0);
		if(client_data_sockfd<0)
		{
			printf("create client_data_sockfd failed.");
			return -1;
		}
		//为客户端地址client_addr随机选取一个地址
		//int data_port=rand_local_port();
		bzero(&client_addr, sizeof(client_addr));
		client_addr.sin_family=AF_INET;					//TCP/IP协议族
		client_addr.sin_addr.s_addr=htonl(INADDR_ANY);  //地址为本机ip
		client_addr.sin_port=0;					//端口为随机选取

		if(bind(client_data_sockfd, (struct sockaddr *)&client_addr, sizeof(client_addr))<0)
		{
			perror("bind");
			return -1;
		}
		if(listen(client_data_sockfd,3)<0)
		{
			perror("listen");
			return -1;
		}
		int len = sizeof(client_addr);
		getsockname(client_data_sockfd, (struct sockaddr*)&client_addr, &len);
		
		unsigned int ip;
		unsigned short port;
		ip = ntohs(client_addr.sin_addr.s_addr);
		port = ntohs(client_addr.sin_port);
		char address[24];
		address[0] = '\0';

		strcat(address, my_itoa((int)((ip>>24)&0xff)) );
		strcat(address, ",");
		strcat(address, my_itoa((int)((ip>>16)&0xff)) );
		strcat(address, ",");
		strcat(address, my_itoa((int)((ip>>8)&0xff)) );
		strcat(address, ",");
		strcat(address, my_itoa((int)((ip)&0xff)) ); 
		strcat(address, ",");
		strcat(address, my_itoa((int)((port>>8)&0xff)) );
		strcat(address, ",");
		strcat(address, my_itoa((int)((port)&0xff)) );

		send_cmd("PORT ", address, client_sockfd);
		if(get_reply(client_sockfd)!=200)
		{
			printf("can not use PORT mode! Please use \"passive\" change to PASV mode.\n");
			return -1;
		}
		else 
			return client_data_sockfd;
		//} //end while
		close(client_data_sockfd);
		return -1;
	}  //end else (PORT mode)
}

//-------------------------------------------------------------------------------------------------
int port_accept(int client_data_sockfd)   // 在port模式下时候用来accept对方的connect后建立数据通路 返回新的数据的sockfd
{
	int set=sizeof(client_addr);
	int new_sockfd=accept(client_data_sockfd, (struct sockaddr*) &client_addr, (socklen_t *)&set);  
										// new_sockfd是用于port模式下accept对方的connect后建立数据通路的。
	if(new_sockfd<0)
	{
		printf("Sorry you can't use PORT mode..\n");
		//close(new_sockfd);
		close(client_data_sockfd);
		return -1;
	}
	close(client_data_sockfd);
	return new_sockfd;
}

//-------------------------------------------------------------------------------------------------
void show_command()
{
	printf("bye:                              terminate ftp session and exit\n");
	printf("cd     remote-directory:        change remote working directory\n");
	printf("close:                            terminate ftp session\n");
	printf("delete remote-file:               delete remote file\n");
	printf("get    remote-file [local-file]:  receive file\n");
	printf("help:                             print local help information\n");
	printf("lcd    local-directory:           change local working directory\n");
	printf("ldir:                             list contents of local directory\n");
	printf("lmkdir directory-name:            make directory on the local machine\n");
	printf("lpwd:                             print local working directory\n");
	printf("lrmdir directory-name:            remove directory on the local machine\n");
	printf("ls:                               list contents of remote directory\n");
	printf("mirror [remote [local]]:          receive remote fold\n");
	printf("mkdir  directory-name:            make directory on the remote machine\n");
	printf("open   host-name [port]:          connect to remote ftp\n");
	printf("passive:                          enter passive transfer mode\n");
	printf("put    local-file [remote-file]:  send one file\n");
	printf("pwd:                              printf remote working directory\n");
	printf("quit:                             terminate ftp session and exit\n");
	printf("rename from-name to-name:         rename file\n");
	printf("rmdir  directory-name:            remove directory on the remote machine\n");
	printf("user:                             send new user information\n");
	printf("?:                                printf local help information\n");
	return;
}

//-------------------------------------------------------------------------------------------------