server.c

socket通信模型

#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#define SIZE 1024

char *site="166.111.107.7";

void printusage()
{
	printf("please enter port and filename \n \n");
}


int sendfile(const char *ip, char *file, int port)
{
	//system("clear");
	char	buf[SIZE];
	int		s,k,f,des;
	
	int		len=sizeof(struct sockaddr_in);
	struct	hostent *hp;
	/*struct hostent 
	{
		char	*h_name;
		char	**h_aliases;
		int		h_addrtype;
		int		h_length;
		char	**h_addr_list;
	};*/

	struct	sockaddr_in addr;
	/*在netinet/in.h中定义
	struct sockaddr_in
	{
		short int sin_family; /* sin_family指代协议族，在socket编程中只能是AF_INET
		unsigned short int sin_port; /* sin_port存储端口号（使用网络字节顺序）
		struct in_addr sin_addr; /* sin_addr存储IP地址，使用in_addr这个数据结构
		unsigned char sin_zero[8]; /* sin_zero是为了让sockaddr与sockaddr_in两个数据结构保持大小相同而保留的空字节。
	};

	/*根据主机名查找主机的IP，别名*/
	hp=gethostbyname(ip);
	if (hp==NULL)
	{
		perror( "hostent error" );
		return -2;
	}
	
	/*创建Socket套接字*/
	if((s=socket(AF_INET,SOCK_STREAM,0))<0)
	{
		perror( "socket error" );
		return( -1 ); 
	}
	/*初始化与赋值*/
	memset(&addr,0,sizeof(struct sockaddr_in));
	addr.sin_family=AF_INET;
	addr.sin_port=htons(port);
	//addr.sin_addr.s_addr=inet_addr(ip);
	memcpy(&addr.sin_addr,hp->h_addr_list[0],hp->h_length);
	//addr.sin_addr.s_addr= htonl(INADDR_ANY);
	
	/*显示信息*/
	printf("Server %s:%d 等待连接....\n",ip,port);
	
	/*与本机地址以及一个本地端口号绑定*/
	if(bind(s,( struct sockaddr * )&addr,sizeof(addr))<0)
	{
		perror("bind");
		exit(1);
	}
	
	/*在创建的Socket上监听*/
	if(listen(s,5)<0){
		perror("listen ");
	exit(5);
	}
	
	/*打开文件*/
	if ( (f=open(file,O_RDONLY)) < 0 )
	{
		perror("file open ");
		exit(5);
	} 
	
	/*服务端主循环*/
	while(1)
	{
		if( (des=accept(s,(struct sockaddr *)&addr,(socklen_t*)&len)) >=0 )
		{
			printf(" start %s send to %s ",file,inet_ntoa(addr.sin_addr));
		}
		else
		{
				perror("accept");
				exit(5);
		}

		lseek (f,0,SEEK_SET);
	
		//write(des,"welcome to server",20);
		while((k=read(f,buf,sizeof(buf)))>0)
		write(des,buf,k); 
		close(des);
	}
	close(f);
	// close(s);
	return 0;
}

/*程序主函数*/
int	main(int argc, char* argv[])
{
		if(argc!=4)
			printusage();
		else
			sendfile(argv[1],argv[3],atoi(argv[2]));
		return 0;
}