#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>

#define ERR_EXIT(m) \
	do \
	{ \
		perror(m);	\
		exit(EXIT_FAILURE);\
	}while(0)
struct packet//自定义包体，自定义协议
{
	int len;
	char buf[1024];
};


//读确定大小的包
//ssize_t有符号数，size_t为无符号数
ssize_t readn(int fd, void *buf, size_t count)
{
	size_t nleft=count;//剩余字节数
	ssize_t nread;//已经接受的字节数
	char *bufp = (char*)buf;//

	while(nleft>0)
	{
		if((nread=read(fd, bufp, nleft))<0)
		{
			if(errno==EINTR)//信号中断
			{
				continue;
			}
			return -1;//否则出错
		}
		else if(nread==0)//表示对方关闭传送
		{
			return count-nleft;//返回已读字节数
		}
		bufp+=nread;//进行指针偏移
		nleft -= nread;
	} 
	return count;
}
ssize_t writen(int fd, const void *buf, size_t count)
{
	size_t nleft=count;//剩余字节数
	ssize_t nwritten;//已经写入的字节数
	char *bufp = (char*)buf;//

	while(nleft>0)
	{
		if((nwritten=write(fd, bufp, nleft))<0)
		{
			if(errno==EINTR)//信号中断
			{
				continue;
			}
			return -1;//否则出错
		}
		else if(nwritten==0)
		{
			continue;
		}
		bufp+=nwritten;//进行指针偏移
		nleft -= nwritten;
	} 
	return count;
}

void do_service(int conn)//执行连接建立后，内容读取，和返回内容
{
	struct packet recvbuf;
	int n;
		while(1)
		{
			memset(&recvbuf, 0, sizeof(recvbuf));
			int ret = readn(conn, &recvbuf.len,4);//先接受包头
			if(ret==-1)//读取失败则退出
			ERR_EXIT("read");
			else if(ret<4)//客户端关闭
			{
				printf("client_close\n");
				break;
			}
			
			n=ntohl(recvbuf.len);
			ret = readn(conn, &recvbuf.buf,n);
			if(ret==-1)//读取失败则退出
				ERR_EXIT("read");
			else if(ret<n)//客户端关闭
			{
				printf("client_close\n");
				break;
			}
			fputs(recvbuf.buf,stdout);//打印标准输出
			writen(conn,&recvbuf,4+n);
		}
}
int main(void)
{
	int listenfd;//建立套接字
	if((listenfd=socket(PF_INET,SOCK_STREAM,IPPROTO_TCP))<0)
/*	if((listenfd=socket(PF_INET,SOCK_STREAM<0))<0)*/
	ERR_EXIT("socket");
	//建立服务器地址
	struct sockaddr_in servaddr;
	memset(&servaddr,0,sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(5188);
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	/*servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");*/
	/*inet_aton("127.0.0.1",&servaddr.sin_addr);*/

	 int on = 1;
	 //为了使服务器处于TIME_WATTING状态，能再次绑定地址
	 if(setsockopt(listenfd,SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on))<0)
	 ERR_EXIT("setsockopt");
	 //绑定地址
	if(bind(listenfd,(struct sockaddr*)&servaddr,sizeof(servaddr))<0)
	ERR_EXIT("bind");
	//监听套接字
	if(listen(listenfd,SOMAXCONN)<0)//套接字变为被动套接字
	ERR_EXIT("listen");
	//存放客户端地址
	struct sockaddr_in peeraddr;
  	socklen_t peerlen =sizeof(peeraddr);
  	
	int conn;//接受accept的套接字
	//建立子进程，以便于多个连接进入服务器
	pid_t pid;
	while(1)
	{
		if((conn=accept(listenfd, (struct sockaddr*)&peeraddr, &peerlen))<0)//套接字变为主动，且以后使用accept返回的套接字;
		ERR_EXIT("accept");
		printf("ip=%s port=%d\n", inet_ntoa(peeraddr.sin_addr), ntohs(peeraddr.sin_port));
		pid=fork();
		if(pid==-1)
		ERR_EXIT("fork");
		if(pid==0)
		{
			close(listenfd);//子进程不再监听套接字
			do_service(conn);
			exit(EXIT_SUCCESS);
		}
		else
			close(conn);
	}
	
	return 0;
}

#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>

#define ERR_EXIT(m) \
	do \
	{ \
		perror(m);	\
		exit(EXIT_FAILURE); \
	}while(0)
struct packet
{
	int len;
	char buf[1024];
};
//读确定大小的包
//ssize_t有符号数，size_t为无符号数
ssize_t readn(int fd, void *buf, size_t count)
{
	size_t nleft=count;//剩余字节数
	ssize_t nread;//已经接受的字节数
	char *bufp = (char*)buf;//

	while(nleft>0)
	{
		if((nread=read(fd, bufp, nleft))<0)
		{
			if(errno==EINTR)//信号中断
			{
				continue;
			}
			return -1;//否则出错
		}
		else if(nread==0)//表示对方关闭传送
		{
			return count-nleft;//返回已读字节数
		}
		bufp+=nread;//进行指针偏移
		nleft -= nread;
	} 
	return count;
}
ssize_t writen(int fd, const void *buf, size_t count)
{
	size_t nleft=count;//剩余字节数
	ssize_t nwritten;//已经写入的字节数
	char *bufp = (char*)buf;//

	while(nleft>0)
	{
		if((nwritten=write(fd, bufp, nleft))<0)
		{
			if(errno==EINTR)//信号中断
			{
				continue;
			}
			return -1;//否则出错
		}
		else if(nwritten==0)
		{
			continue;
		}
		bufp+=nwritten;//进行指针偏移
		nleft -= nwritten;
	} 
	return count;
}
int main(void)
{
	int sock;
	if((sock=socket(PF_INET,SOCK_STREAM,IPPROTO_TCP))<0)
/*	if((listenfd=socket(PF_INET,SOCK_STREAM<0))<0)*/
	ERR_EXIT("socket");
	
	struct sockaddr_in servaddr;
	memset(&servaddr,0,sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(5188);
	/*servaddr.sin_addr.s_addr = htonl(INADDR_ANY);*/
	servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	/*inet_aton("127.0.0.1",&servaddr.sin_addr);*/
//发起连接
	if(connect(sock,(struct sockaddr*)&servaddr,sizeof(servaddr))<0)
		ERR_EXIT("connect");

	struct packet recvbuf;
	struct packet sendbuf;
	memset(&sendbuf, 0, sizeof(sendbuf));
	memset(&recvbuf, 0, sizeof(recvbuf));
	
	int n=0;
	while(fgets(sendbuf,sizeof(sendbuf), stdin) !=NULL)
	{
		n=strlen(sendbuf.buf);
		sendbuf.len=htonl(n);

		writen(sock, &sendbuf, 4+n);

		int ret = readn(sock, &recvbuf.len,4);//先接受包头
		if(ret==-1)//读取失败则退出
		ERR_EXIT("readn");
		else if(ret<4)//客户端关闭
		{
			printf("client_close\n");
			break;
		}
			
		n=ntohl(recvbuf.len);
		ret = readn(sock, &recvbuf.buf,n);
		if(ret==-1)//读取失败则退出
			ERR_EXIT("readn");
		else if(ret<n)//客户端关闭
		{
			printf("client_close\n");
			break;
		}
		fputs(recvbuf.buf,stdout);//打印标准输出
		
		memset(&sendbuf,0, sizeof(sendbuf));
		memset(&recvbuf, 0, sizeof(recvbuf));
	}
	close(sock);
	return 0;
}