通过TCP通信进行文件收发

发送端：

/**************************************
				客户端
**************************************/

#include <stdio.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h> /* superset of previous */
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <pthread.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>


int sockfd;


//./main   192.168.5.2   filename 

//获取文件的大小
int get_file_size(char *filename)
{
	int fd = open(filename,O_RDWR);
		if(fd < 0)
		{
			perror("open fail:");
			exit(0);
		}
	
	//把文件光标偏移到末尾获取文件的大小 
 	int size = lseek(fd,0,SEEK_END);
	
		close(fd);
		return size;
	
}



int main(int argc, char **argv)
{
	if(argc != 3)
	{
		perror("input IP and filename:");
		return -1;
	}
	
	//1.创建网络通信对象
	sockfd = socket(AF_INET, SOCK_STREAM , 0);
	if (sockfd == -1) 
	{
		perror("socket error!");
		return 0;
	}

	//2.定义网络信息结构体
    struct sockaddr_in seraddr;
    seraddr.sin_family = AF_INET;
    seraddr.sin_port = htons(3333); 
    seraddr.sin_addr.s_addr = inet_addr(argv[1]);

	//3.链接网络服务器
	int ret = connect(sockfd,  (struct sockaddr *)&seraddr, sizeof(struct sockaddr));
	if (ret == -1)
	{
		perror("connect error");
		return 0;
	}
	else
	{
		printf("connect ok\n");
	}

	//打开文件并获取文件的大小  
	 int filesize = get_file_size(argv[2]);
	
	
	//发送文件名与文件的大小  
	char cmd[1024]={0};  
	
	//数据格式  filename size  
	sprintf(cmd,"%s %d",argv[2],filesize);
	write(sockfd,cmd,strlen(cmd));
	
	//等待对方回应  
	char ret_data[10];
	printf("等待对方回应\n");
	read(sockfd,ret_data,10);
	
	//发送文本内容
	if(strstr(ret_data,"OK"))
	{
		 //打开源文件发送数据 
		 int fd = open(argv[2],O_RDWR);
			
		 //发送文本内容
		 while(1)
		 {
			 char buf[1024]={0};
			 int size = read(fd,buf,1024);
				if(size == 0)
				{
					printf("文件发送完毕\n");
					close(fd); 
					break;
				}
			 write(sockfd,buf,size);
			 
		 }			 
		 
		 
		
	}
	else
	{
		printf("对方拒绝接收文件\n");
		exit(0);
		
	}
	

	
}

接收端：

/**************************************
				服务端
**************************************/


#include <stdio.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h> /* superset of previous */
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdlib.h>
#include <pthread.h>
 #include <sys/types.h>
       #include <sys/stat.h>
       #include <fcntl.h>


int new_sockfd;

int main(int argc, char **argv)
{
	//1.创建网络通信对象
	int sockfd = socket(AF_INET, SOCK_STREAM , 0);
	if (sockfd == -1) 
	{
		perror("socket error!");
		return 0;
	}

	//2.设置服务器的IP地址信息
    struct sockaddr_in seraddr;
    seraddr.sin_family = AF_INET;
    seraddr.sin_port = htons(3333); 
    seraddr.sin_addr.s_addr = inet_addr("0.0.0.0");
	//0.0.0.0  万用地址，让系统自动监听本地网卡
	//3.绑定（注册）服务器IP地址信息
	int ret = bind(sockfd, (struct sockaddr *)&seraddr,sizeof(struct sockaddr));
	if (ret != 0)
	{
		perror("bind error");
		return 0;
	}
	else
	{
		printf("bind ok\n");
	}

	//4.把网络地址设置为监听模式
	ret = listen(sockfd, 10);
	if (ret != 0)
	{
		perror("listen error");
		return 0;
	}
	else
	{
		printf("listen ok\n");
	}
	//5.等待链接请求
	printf("等待监听请求\n");
	//获取客户端信息
	struct sockaddr_in address;
	int len = sizeof(address);
	new_sockfd = accept(sockfd, (struct sockaddr *)&address, &len);
	if (new_sockfd < 0)
	{
		printf("accept error\n");
		return 0;
	}

	printf("port = %d\n", ntohs(address.sin_port));
	printf("ip = %s\n", inet_ntoa(address.sin_addr));



	//接受客户端发送过来的数据  
	
	//读取头信息
    char head[1024]={0};    
	read(new_sockfd,head,1024);
	
	if(strstr(head," "))
	{
		printf("用户发送文件是否接收  1 OK  2 NO\n");
		int a = 0; 
		scanf("%d",&a);
		if(a == 1)  //接收
		{
			write(new_sockfd,"OK",strlen("OK")); 
			
			//创建新文件  
			char filename[1024]={0};
			int  filesize=0;
			sscanf(head,"%s %d",filename,&filesize);
			
			filename[0] = 'N';
			printf("%s %d\n",filename,filesize);
			
			int fd = open(filename,O_RDWR|O_CREAT|O_TRUNC,0777);
			
			//开始接收文本数据  
			int len=0;
			while(1)
			{	
				char buf[1024]={0};
				int ret = read(new_sockfd,buf,1024);
					len+= ret; 
					write(fd,buf,ret);
				
					if(len == filesize)
					{
						printf("文件接收完毕\n");
						close(fd);
						break;
					}
				
			}
			
			
			
			
			
		}
		else
		{
			write(new_sockfd,"NO",strlen("NO")); 
		}
		
		
	}
	else
	{
		printf("head=%s\n",head);
		
	}
	
	
}