网络编程【实现tftp上传功能】

简介

通过tcp连接实现客户端上传，服务器端下载功能，需要注意字符串的解析以及粘包问题

客户端

头文件

#ifndef _MIAN_H_
#define _MIAN_H_

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
//字符串解析
int parseStr(char *str,char *cmd,char *filename);
//业务处理
int do_work(int sockfd,char *cmd,char *filename); 
int upload(int sockfd,char *filename);
#endif

客户端通过tcp连接到服务器端

#include "./main.h"
//实现客户的tcp连接
//---------子函数-----------
// 创建socket并连接到服务器
int tcp_connect(const char *ip,int port)
{
	//创建socket
	int tcp_socket = socket(AF_INET,SOCK_STREAM,0);
	if(tcp_socket < 0)
	{
		perror("socket error");
		return -1;
	}
	printf("socket ok!\n");
	//连接服务器
	//定义地址信息、赋值
	struct sockaddr_in server;
	server.sin_family = AF_INET;
	server.sin_port = htons(port);
	server.sin_addr.s_addr = inet_addr(ip);
	if(connect(tcp_socket,(struct sockaddr*)&server,sizeof(server)) < 0)
	{
		perror("connect error");
		return -1;
	}
	return tcp_socket;
}

//tcp通信
int tcp_com(int sockfd)
{
	//发送消息
	char buf[100] = {'\0'};
	char cmd[50] = {'\0'};
	char filename[50] = {'\0'};
	printf("input cmd filename:");
	while(1)
	{
		fgets(buf,sizeof(buf),stdin);
		send(sockfd,buf,strlen(buf),0);
		if(strncasecmp(buf,"quit",4) == 0) return -1;
		//调用解析函数
		parseStr(buf,cmd,filename);
		printf("cmd is %s\nfilename is %s\n",cmd,filename);
		//业务处理
		do_work(sockfd,cmd,filename);
		memset(buf,'\0',sizeof(buf));
	}
}

int main(int argc, const char *argv[])
{
	//参数判断
	if(argc < 3)
	{
		perror("input ./app ip port");
		return -1;
	}
	int sockfd = tcp_connect(argv[1],atoi(argv[2]));
	int flag = tcp_com(sockfd);
	if(flag < 0)
	{
		close(sockfd);
	}
	return 0;
}

字符串解析函数

#include "./main.h"
//tftp的字符串解析
int parseStr(char *str,char *cmd,char *filename);


int parseStr(char *str,char *cmd,char *filename)
{
	//入参判断
	if(NULL == str || NULL == cmd || NULL == filename)
	{
		perror("NULL error");
		return -1;
	}
	//puts("success");
	while(*str != '#')
	{
		if(*str == ' ') break;
		*cmd = *str;
		str++;
		cmd++;
	}
	*cmd = '\0';
	str++;
	while(*str!='#')
	{
		*filename = *str;
		str++;
		filename++;
	}
	*filename = '\0';
	//printf("success\n");
	return 0;
}

上传函数

#include "./main.h"
//业务处理函数
//完成tftp功能，客户端
int do_work(int sockfd,char *cmd,char *filename);
int upload(int sockfd,char *filename);
int upload(int sockfd,char *filename)
{
	//获取文件大小
	struct stat myFile;
	if(stat(filename,&myFile) < 0)
	{
		perror("stat error");
		return -1;
	}
	int fileSize = myFile.st_size;
	printf("fileSize = %d\n",fileSize);
	//发送文件大小给服务器端
	sleep(3);
	send(sockfd,&fileSize,sizeof(fileSize),0);
	//发送文件内容,先打开文件，再传
	int fd = open(filename,O_RDONLY);
	char buf[100] = {'\0'};
	int ret = 0;
	printf("发送数据中。。。\n");
	while(1)
	{
		ret = read(fd,buf,sizeof(buf));
		if(0 == ret)
		{
			break;
		}
		send(sockfd,buf,ret,0);
		memset(buf,'\0',sizeof(buf));
	}
	printf("发送完毕\n");
	close(fd);
	return 0;
}

int do_work(int sockfd,char *cmd,char *filename)
{
	if(strncmp(cmd,"put",3) == 0)
	{
		//上传文件
		printf("上传文件\n");
		upload(sockfd,filename);
	}else if(strncmp(cmd,"get",3) == 0)
	{
		//下载文件
	}
	return 0;
}

服务器端

头文件

#ifndef _MIAN_H_
#define _MIAN_H_

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
int parseStr(char *str,char *cmd,char *filename);
int do_work(int newfd,char *cmd,char *filename);
int down_load(int newfd,char *filename);
#endif

服务器端建立tcp连接

#include "./main.h"

//------子函数-------
//tcp监听
int tcp_server(const char *ip,int port)
{
	//创建socket对象
	int tcp_socket = socket(AF_INET,SOCK_STREAM,0);
	if(tcp_socket < 0)
	{
		perror("socket error");
		return -1;
	}
	printf("socket ok!\n");
	//绑定ip和端口号
	struct sockaddr_in MyAddr;
	memset(&MyAddr,'\0',sizeof(MyAddr));
	MyAddr.sin_family = AF_INET;
	MyAddr.sin_port = htons(port);
	MyAddr.sin_addr.s_addr = inet_addr(ip);
	if(bind(tcp_socket,(struct sockaddr *)&MyAddr,sizeof(MyAddr)) < 0)
	{
		perror("bind error");
		return -1;
	}
	printf("bind ok!\n");
	//监听
	if(listen(tcp_socket,5) < 0)
	{
		perror("listen error");
		return -1;
	}
	printf("listen ok!\n");
	//返回监听的端口号
	return tcp_socket;
}
//tcp通信
int tcp_com(int newfd)
{
	char buf[100] = {'\0'};
	char cmd[50] = {'\0'};
	char filename[50] = {'\0'}; 
	while(1)
	{	//接收消息
		memset(buf,'\0',sizeof(buf));
		recv(newfd,buf,sizeof(buf),0);
		if(strncasecmp(buf,"quit",4) == 0)
		{
			return -1;
		}
		//解析
		parseStr(buf,cmd,filename);	
		printf("cmd is %s\nfilename is %s\n",cmd,filename);
		//业务处理
		do_work(newfd,cmd,filename);
	}
}

int main(int argc, const char *argv[])
{
	if(argc < 3)
	{	
		printf("input add ip port\n");
		return -1;
	}
	//监听
	int listenfd = tcp_server(argv[1],atoi(argv[2]));
	//建立通信
	struct sockaddr_in client;
	memset(&client,'\0',sizeof(client));
	int len = sizeof(client);
	int newfd = accept(listenfd,(struct sockaddr *)&client,&len);
	if(newfd < 0)
	{
		perror("accept error");
		return -1;
	}
	//输出客户端的ip port
	printf("client ip is %s port is %d\n",inet_ntoa(client.sin_addr),ntohs(client.sin_port));
	//tcp通信
	int n = tcp_com(newfd);
	if(n < 0)
	{
		close(newfd);
	}
	close(listenfd);
	return 0;
}

字符串解析函数

#include "./main.h"
//tftp的字符串解析
int parseStr(char *str,char *cmd,char *filename);


int parseStr(char *str,char *cmd,char *filename)
{
	//入参判断
	if(NULL == str || NULL == cmd || NULL == filename)
	{
		perror("NULL error");
		return -1;
	}
	while(*str != '#')
	{
		if(*str == ' ') break;
		*cmd = *str;
		str++;
		cmd++;
	}
	*cmd = '\0';
	str++;
	while(*str!='#')
	{
		*filename = *str;
		str++;
		filename++;
	}
	*filename = '\0';
	return 0;
}

服务器端下载

#include "./main.h"
//业务处理
//完成tftp功能，服务器端

int do_work(int newfd,char *cmd,char *filename);
int down_load(int newfd,char *filename);
//下载
int down_load(int newfd,char *filename)
{
	//接收文件大小
	//printf("success\n");
	int fileSize = 0;
	recv(newfd,&fileSize,sizeof(fileSize),0);
	//printf("recv success\n");
	printf("fileSize = %d\n",fileSize);
	//接收文件保存到本地
	char buf[100] = {'\0'};
	int fd = open(filename,O_WRONLY|O_CREAT|O_TRUNC,0777);
	int count = 0;
	int ret = 0;
	printf("接收数据中。。。\n");
	while(count < fileSize)
	{
		//printf("recv success\n");
		ret = recv(newfd,buf,sizeof(buf),0);
		//写入到文件中
		write(fd,buf,ret);
		count += ret;
		memset(buf,'\0',sizeof(buf));
	}
	printf("接收数据成功\n");
	close(fd);
	return 0;
}
//业务处理
int do_work(int newfd,char *cmd,char *filename)
{
	if(strncmp(cmd,"puts",3) == 0)
	{
		//下载文件
		printf("开始下载文件\n");
		down_load(newfd,filename);
	}
	else if(strncmp(cmd,"gets",3) == 0)
	{
		//上传文件
	}
	return 0;
}