计算机网络-第7章 网络安全（1）

TCP并发模型：

1. TCP多线程模型：

    缺点：创建线程会带来资源开销，能够实现的并发量比较有限。

2. IO模型：

    1. 阻塞IO：

        没有数据到来时，可以让任务挂起，节省CPU资源开销，提高系统效率

    2. 非阻塞IO：

        程序未接收到数据时一直执行，效率很低

        举例应用：

write.c

#include "head.h"

int main(void)
{
	int fd = 0;
	char tmpbuff[1024] = {0};

	mkfifo("/tmp/myfifo", 0664);
	fd = open("/tmp/myfifo", O_WRONLY);
	if(fd == -1)
	{
		perror("fail to open");
		return -1;
	}

	while(1)
	{
		memset(tmpbuff, 0, sizeof(tmpbuff));
		gets(tmpbuff);
		write(fd, tmpbuff, strlen(tmpbuff));
	}

	close(fd);
	return 0;
}

        后面的举例应用的write.c都为上面所示

read.c

#include "head.h"

int main(void)
{
	int fd = 0;
	int flags = 0;
	ssize_t nsize = 0;
	char *pret = NULL;
	char tmpbuff[1024] = {0};

	mkfifo("/tmp/myfifo", 0664);
	fd = open("/tmp/myfifo", O_RDONLY);
	if(fd == -1)
	{
		perror("fail to open");
		return -1;
	}
	
	flags = fcntl(fd, F_GETFL);
	flags |= O_NONBLOCK;
	fcntl(fd, F_SETFL, flags);

	flags = fcntl(0, F_GETFL);
	flags |= O_NONBLOCK;
	fcntl(0, F_SETFL, flags);

	while(1)
	{
		memset(tmpbuff, 0, sizeof(tmpbuff));
		pret = gets(tmpbuff);
		if(pret != NULL)
		{
			printf("STDIN:%s\n", tmpbuff);
		}

		memset(tmpbuff, 0, sizeof(tmpbuff));
		nsize = read(fd, tmpbuff, sizeof(tmpbuff));
		if(nsize > 0)
		{
			printf("RECV:%s\n", tmpbuff);
		}
	}
	
	close(fd);
	return 0;
}

        通过fcntl将fd和stdin文件描述符设置为非阻塞IO，所以read.c既可以通过管道接收消息，也可以同终端输入，接收消息，二者不会堵塞。

    3. 异步IO：

        只能绑定一个文件描述符用来读取数据

        举例应用：

read.c

#include "head.h"

int fd = 0;

void handler(int signo)
{
	char tmpbuff[1024] = {0};
	ssize_t nsize = 0;

	memset(tmpbuff, 0, sizeof(tmpbuff));
	nsize = read(fd, tmpbuff, sizeof(tmpbuff));
	if(nsize > 0)
	{
		printf("RECV:%s\n", tmpbuff);
	}

	return;

}

int main(void)
{
	int flags = 0;
	ssize_t nsize = 0;
	char *pret = NULL;
	char tmpbuff[1024] = {0};

	signal(SIGIO, handler);

	mkfifo("/tmp/myfifo", 0664);
	fd = open("/tmp/myfifo", O_RDONLY);
	if(fd == -1)
	{
		perror("fail to open");
		return -1;
	}
	
	flags = fcntl(fd, F_GETFL);
	flags |= O_ASYNC;
	fcntl(fd, F_SETFL, flags);
	fcntl(fd, F_SETOWN, getpid());

	while(1)
	{
		memset(tmpbuff, 0, sizeof(tmpbuff));
		gets(tmpbuff);
		printf("STDIN:%s\n", tmpbuff);

	}
	
	close(fd);
	return 0;
}

    4. 多路复用：

        1. select：

            1. select监听的集合中的文件描述符有上限限制

            2. select有内核层向用户层数据空间拷贝的过程，占用系统资源开销

                原因：在使用select函数时，会涉及到内核层和用户层之间的数据传输。具体来说：select函数在内核层会监视一组文件描述符的状态变化，并在有变化发生时通知用户层。为了是实现这个功能，内核会定期检测文件描述符的状态，并在发生变化时将相关信息传递给用户层。这个过程涉及到内核层和用户层之间的数据传输，即内核层需要将监视的文件描述符的状态信息传递给用户层。这个传输过程会涉及到系统资源的开销，因为需要进行数据拷贝操作，将内核中的数据拷贝到用户空间，这个数据拷贝的过程会消耗一定的系统资源。

            3. select必须轮询检测产生事件的文件描述符

            4. select只能工作在水平触发模式(低速模式)，无法工作在边沿触发模式(高速模式)

                原因：

                    1. 在水平触发模式下，一旦文件描述符中的数据可读或可写，select就会通知用户程序，并且如果这些描述符在之后的select调用中仍然保持可读或可写状态，select会再次通知程序。换句话说，在水平触发模式下，只要描述符的状态处于可读或可写状态，select就会通知程序。

                    2. 在边缘触发模式下，只有当描述符的状态发生变化时才会通知程序，这意味着如果描述符中的数据量发生变化或者有新的数据到达，程序才会被通知，而如果描述符的状态保持不变，即使在之后的select调用中它任然处于可读或可写状态，程序也不会被通知。

            举例应用：

read.c

#include "head.h"

int main(void)
{
	int fd = 0;
	int flags = 0;
	ssize_t nsize = 0;
	char *pret = NULL;
	fd_set rdfds;
	fd_set tmpfds;
	int ret = 0;
	char tmpbuff[1024] = {0};

	mkfifo("/tmp/myfifo", 0664);
	fd = open("/tmp/myfifo", O_RDONLY);
	if(fd == -1)
	{
		perror("fail to open");
		return -1;
	}
	
	FD_ZERO(
	FD_SET(fd, 
	FD_SET(0, 
	
	while(1)
	{
		tmpfds = rdfds;
		ret = select(fd+1, &tmpfds, NULL, NULL, NULL);
		if(ret == -1)
		{
			perror("fail to select");
			return -1;
		}
		
		if(FD_ISSET(0, &tmpfds))
		{
			memset(tmpbuff, 0, sizeof(tmpbuff));
			gets(tmpbuff);
			printf("STDIN:%s\n", tmpbuff);
		}

		if(FD_ISSET(fd, &tmpfds))
		{
			memset(tmpbuff, 0, sizeof(tmpbuff));
			read(fd, tmpbuff, sizeof(tmpbuff));
			printf("FIFO:%s\n", tmpbuff);
		}
	}

	close(fd);
	return 0;
}

        2. poll：

            1. poll有内核层向用户层数据空间拷贝的过程，占用系统资源开销

            2. poll必须轮询检测产生事件的文件描述符

            3. poll只能工作在水平触发模式(低速模式)，无法工作在边沿触发模式(高速模式)

            举例应用：

read.c

#include "head.h"

int main(void)
{
	int fd = 0;
	int ret = 0;
	int flags = 0;
	ssize_t nsize = 0;
	struct pollfd fds[2];
	char tmpbuff[1024] = {0};


	mkfifo("/tmp/myfifo", 0664);
	fd = open("/tmp/myfifo", O_RDONLY);
	if(fd == -1)
	{
		perror("fail to open");
		return -1;
	}
	
	fds[0].fd = 0;
	fds[0].events = POLLIN;
	fds[1].fd = fd;
	fds[1].events = POLLIN;

	while(1)
	{
		ret = poll(fds, 2, -1);
		if(ret == -1)
		{
			perror("fail to poll");
			return -1;
		}

		if(fds[0].revents & POLLIN)
		{
			memset(tmpbuff, 0, sizeof(tmpbuff));
			gets(tmpbuff);
			printf("STDIN:%s\n", tmpbuff);
		}

		if(fds[1].revents & POLLIN)
		{
			memset(tmpbuff, 0, sizeof(tmpbuff));
			read(fd, tmpbuff, sizeof(tmpbuff));
			printf("FIFO:%s\n", tmpbuff);
		}
	}
	
	close(fd);
	return 0;
}

        3. epoll：

            1. epoll没有文件描述符上限限制

            2. epoll创建内核监听事件表，所以只需要在内核空间完成数据拷贝即可

            3. epoll会将产生事件的文件描述符对应的事件直接返回

            4. epoll可以工作在水平触发模式(默认：低速模式)，还可以工作在边沿触发模式(高速模式) 在epoll_events的结构体中的events传入EPOLLIN | EPOLLET即可

            举例应用：

read.c

#include "head.h"

int main(void)
{
	int i = 0;
	int fd = 0;
	int epfd = 0;
	int nready = 0;
	ssize_t nsize = 0;
	char tmpbuff[1024] = {0};
	struct epoll_event env;
	struct epoll_event retenv[2];

	mkfifo("/tmp/myfifo", 0664);
	fd = open("/tmp/myfifo", O_RDONLY);
	if(fd == -1)
	{
		perror("fail to open");
		return -1;
	}
	
	epfd = epoll_create(2);
	if(epfd == -1)
	{
		perror("fail to epoll_create");
		return -1;
	}
	
	env.data.fd = 0;
	env.events = EPOLLIN;
	epoll_ctl(epfd, EPOLL_CTL_ADD, 0, 
	env.data.fd = fd;
	env.events = EPOLLIN;
	epoll_ctl(epfd, EPOLL_CTL_ADD, fd, 

	while(1)
	{
		nready = epoll_wait(epfd, retenv, 2, -1);
		if(nready == -1)
		{
			perror("fail to epoll_wait");
			return -1;
		}
		
		for(i = 0; i < nready; i++)
		{
			if(retenv[i].data.fd == 0)
			{
				memset(tmpbuff, 0, sizeof(tmpbuff));
				gets(tmpbuff);
				printf("STDIN:%s\n", tmpbuff);
			}
			else if(retenv[i].data.fd == fd)
			{
				memset(tmpbuff, 0, sizeof(tmpbuff));
				read(fd, tmpbuff, sizeof(tmpbuff));
				printf("FIFO:%s\n", tmpbuff);
			}
		}
	}
	
	close(fd);
	return 0;
}

3. 函数接口：

    1. select：

int select(int nfds, fd_set *readfds, fd_set *writefds,fd_set *exceptfds, struct timeval *timeout);

        功能：select监听文件描述符集合中是否有文件描述编程ready状态

        参数：

            nfds：最大文件描述符的值+1

            reafds：读文件描述符集合

            writefds：写文件描述符集合

            exceptfds：其余文件描述符集合

            timeout：等待的时长

                        NULL：一直等待

        返回值：

            成功返回文件描述符集合中的文件描述符个数
            失败返回-1

    void FD_CLR(int fd, fd_set *set);

                功能：判断文件描述符fd是否仍在集合中

    void FD_SET(int fd, fd_set *set);

                功能：将文件描述符fd加入到集合中

    int  FD_ISSET(int fd, fd_set *set);

                功能：判断文件描述符fd是否仍在集合中

    void FD_ZERO(fd_set *set);

                功能：将文件描述符集合清0

    2. poll：

int poll(struct pollfd *fds, nfds_t nfds, int timeout);

        功能：监听文件描述符集合是否有事件发生

        参数：

            fds：监听文件描述符集合是否有时间发生

            nfds：监听文件描述符集合元素个数

            timeout：等待时间（-1一直等待）

struct pollfd {
    int   fd;         /* file descriptor */
    short events;     /* requested events */
    short revents;    /* returned events */
};

                fd：监听的文件描述

                events：要监听的事件，POLLIN：是否可读，POLLOUT：是否可写

                revents：实际产生的事件

    3. epoll：

        1. epoll_create：

int epoll_create(int size);

            功能：创建一张内核事件表

            参数：

                size：事件的个数

            返回值：

                成功返回文件描述符
                失败返回-1

        2. epoll_ctl：

int epoll_ctl(int epfd, int op, int fd, struct epoll_event *event);

            功能：维护epoll时间表

            参数：

                epfd：事件表的文件描述符

                op：

                    EPOLL_CTL_ADD     添加事件

                    EPOLL_CTL_MODE  修改事件

                    EPOLL_CTL_DEL      删除事件

                fd：操作的文件描述符

                events：事件对应的事件

typedef union epoll_data {
    void    *ptr;
    in    fd;
    uint32_t    u32;
    uint64_t    u64;
} epoll_data_t;

struct epoll_event {
    uint32_t     events;      /* Epoll events */
    epoll_data_t data;        /* User data variable */
};

            返回值：

                成功返回0 
                失败返回-1 

        3. epoll_wait：

int epoll_wait(int epfd, struct epoll_event *events, int maxevents, int timeout);

            功能：监听事件表中的事件

            参数：

                epfd：文件描述符

                events：存放实际产生事件的数组空间首地址

                maxevents：最多存放事件的个数

                timeout：设定监听的时间（超过该时间则不再监听）

                        -1：一直监听直到有事件发生

            返回值：

                成功返回产生事件的文件描述符个数
                失败返回-1 
                如果时间达到仍没有事件发生返回0

4. 练习作业：

        1. 编写TCP并发模型之select模型

client.c

#include "head.h"

int CreateTcpClient(char *pip, int port)
{
	int ret = 0;
	int sockfd = 0;
	struct sockaddr_in seraddr;

	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (-1 == sockfd)
	{
		perror("fail to socket");
		return -1;
	}
	
	seraddr.sin_family = AF_INET;
	seraddr.sin_port = htons(port);
	seraddr.sin_addr.s_addr = inet_addr(pip);
	ret = connect(sockfd, (struct sockaddr *)&seraddr, sizeof(seraddr));
	if (-1 == ret)
	{
		perror("fail to connect");
		return -1;
	}
	
	return sockfd;
}

int main(void)
{
	int sockfd = 0;
	char tmpbuff[4096] = {"hello world"};
	int cnt = 0;
	ssize_t nsize = 0;

	sockfd = CreateTcpClient("192.168.1.125", 50000);
	
	while (1)
	{
		memset(tmpbuff, 0, sizeof(tmpbuff));
		sprintf(tmpbuff, "hello world --- %d", cnt);
		cnt++;
		nsize = send(sockfd, tmpbuff, strlen(tmpbuff), 0);
		if (-1 == nsize)
		{
			perror("fail to send");
			return -1;
		}

		memset(tmpbuff, 0, sizeof(tmpbuff));
		nsize = recv(sockfd, tmpbuff, sizeof(tmpbuff), 0);
		if (-1 == nsize)
		{
			perror("fail to recv");
			return -1;
		}

		printf("RECV:%s\n", tmpbuff);
	}

	close(sockfd);

	return 0;
}

        后面的client.c都为上面所示

server.c

#include "head.h"

int CreateListenSocket(char *pip, int port)
{
	int ret = 0;
	int sockfd = 0;
	struct sockaddr_in serveraddr;

	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd == -1)
	{
		perror("fail to socket");
		return -1;
	}
	
	serveraddr.sin_family = AF_INET;
	serveraddr.sin_port = htons(port);
	serveraddr.sin_addr.s_addr = inet_addr(pip);
	ret = bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr));
	if(ret == -1)
	{
		perror("fail to bind");
		return -1;
	}
		

	ret =listen(sockfd, 10);
	if(ret == -1)
	{
		perror("fail to listen");
		return -1;
	}

	return sockfd;
}

int HandleTcpClient(int confd)
{
	char tmpbuff[4096] = {0};
	ssize_t nsize = 0;

	memset(tmpbuff, 0, sizeof(tmpbuff));
	nsize = recv(confd, tmpbuff, sizeof(tmpbuff), 0);
	if(nsize == -1)
	{
		perror("fail to recv");
		return -1;
	}
	else if(nsize == 0)
	{
		return 0;
	}

	sprintf(tmpbuff, "%s ------echo", tmpbuff);
	nsize = send(confd, tmpbuff, strlen(tmpbuff), 0);
	if(nsize == -1)
	{
		perror("fail to send");
		return -1;
	}
	
	return nsize;

}

int main(void)
{
	int i = 0;
	int ret = 0;
	int confd = 0;
	int sockfd = 0;
	fd_set rdfds;
	fd_set tmpfds;
	int maxfd = 0;
	
	sockfd = CreateListenSocket("192.168.1.125", 50000);
	
	FD_ZERO(
	FD_SET(sockfd, 
	maxfd = sockfd;

	while(1)
	{
		tmpfds = rdfds;
		ret = select(maxfd+1, &tmpfds, NULL, NULL, NULL);
		if(ret == -1)
		{
			perror("fail to select");
			return -1;
		}

		if(FD_ISSET(sockfd, &tmpfds))
		{
			confd = accept(sockfd, NULL, NULL);
			if(confd == -1)
			{
				perror("fail to accept");
				FD_CLR(sockfd, 
				close(sockfd);
				continue;
			}

			FD_SET(confd, 
			maxfd = maxfd > confd ? maxfd : confd;
		}

		for(i = sockfd+1; i <= maxfd; i++)
		{
			if(FD_ISSET(i, &tmpfds))
			{
				ret = HandleTcpClient(i);
				if(ret == -1)
				{
					fprintf(stderr, "handle client fialed!\n");
					FD_CLR(i, 
					close(i);
					continue;
				}
				else if(ret == 0)
				{
					fprintf(stderr, "client disconnected!\n");
					FD_CLR(i, 
					close(i);
					continue;
				}
			}
		}
	}
	
	close(confd);
	close(sockfd);

	return 0;
}

        2. 编写TCP并发模型之poll模型

server.c

#include "head.h"

int CreateListenSocket(char *pip, int port)
{
	int ret = 0;
	int sockfd = 0;
	struct sockaddr_in serveraddr;

	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd == -1)
	{
		perror("fail to socket");
		return -1;
	}
	
	serveraddr.sin_family = AF_INET;
	serveraddr.sin_port = htons(port);
	serveraddr.sin_addr.s_addr = inet_addr(pip);
	ret = bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr));
	if(ret == -1)
	{
		perror("fail to bind");
		return -1;
	}
		

	ret =listen(sockfd, 10);
	if(ret == -1)
	{
		perror("fail to listen");
		return -1;
	}

	return sockfd;
}

int HandleTcpClient(int confd)
{
	char tmpbuff[4096] = {0};
	ssize_t nsize = 0;

	memset(tmpbuff, 0, sizeof(tmpbuff));
	nsize = recv(confd, tmpbuff, sizeof(tmpbuff), 0);
	if(nsize == -1)
	{
		perror("fail to recv");
		return -1;
	}
	else if(nsize == 0)
	{
		return 0;
	}

	sprintf(tmpbuff, "%s ------echo", tmpbuff);
	nsize = send(confd, tmpbuff, strlen(tmpbuff), 0);
	if(nsize == -1)
	{
		perror("fail to send");
		return -1;
	}
	
	return nsize;

}

int InitFds(struct pollfd *fds, int maxlen)
{
	int i = 0;

	for(i = 0; i < maxlen; i++)
	{
		fds[i].fd = -1;
	}

	return 0;
}

int AddFds(struct pollfd *fds, int maxlen, int fd, short env)
{
	int i = 0;

	for(i = 0; i < maxlen; i++)
	{
		if(fds[i].fd == -1)
		{
			fds[i].fd = fd;
			fds[i].events = env;
			break;
		}
	}

	if(i == maxlen)
	{
		return -1;
	}

	return 0;
}

int DeleteFds(struct pollfd *fds, int maxlen, int fd)
{
	int i = 0;
	for(i = 0; i < maxlen; i++)
	{
		if(fds[i].fd == fd)
		{
			fds[i].fd = -1;
			break;
		}
	}

	return 0;
}

int main(void)
{
	int i = 0;
	int ret = 0;
	int nready = 0;
	int confd = 0;
	int sockfd = 0;
	struct pollfd fds[1024];

	sockfd = CreateListenSocket("192.168.1.125", 50000);
	
	InitFds(fds, 1024);
	AddFds(fds, 1024, sockfd, POLLIN);

	while(1)
	{
		nready = poll(fds, 1024, -1);
		if(nready == -1)
		{
			perror("fail to poll");
			return -1;
		}
		
		for(i = 0; i < 1024; i++)
		{
			if(fds[i] == -1)
			{
				continue;
			}
			if(fds[i].revents & POLLIN && fds[i].fd == sockfd)
			{
				confd = accept(sockfd, NULL, NULL);
				if(confd == -1)
				{
					perror("fail to accept");
					close(sockfd);
					DeleteFds(fds, 1024, sockfd);
					continue;
				}
				
				AddFds(fds, 1024, confd, POLLIN);
			}
			else if(fds[i].revents & POLLIN && fds[i].fd != sockfd)
			{
				ret = HandleTcpClient(fds[i].fd);
				if(ret == -1)
				{
					fprintf(stderr, "handle tcp client failed!\n");
					close(fds[i].fd);
					DeleteFds(fds, 1024, fds[i].fd);
					continue;
				}
				else if(ret == 0)
				{
					fprintf(stderr, "client disconnected!\n");
					close(fds[i].fd);
					DeleteFds(fds, 1024, fds[i].fd);
					continue;
				}
			}
		}
	}
	
	close(confd);
	close(sockfd);

	return 0;
}

        3. 编写TCP并发模型之epoll模型

server.c

#include "head.h"

int CreateListenSocket(char *pip, int port)
{
	int ret = 0;
	int sockfd = 0;
	struct sockaddr_in serveraddr;

	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd == -1)
	{
		perror("fail to socket");
		return -1;
	}
	
	serveraddr.sin_family = AF_INET;
	serveraddr.sin_port = htons(port);
	serveraddr.sin_addr.s_addr = inet_addr(pip);
	ret = bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr));
	if(ret == -1)
	{
		perror("fail to bind");
		return -1;
	}
		

	ret =listen(sockfd, 10);
	if(ret == -1)
	{
		perror("fail to listen");
		return -1;
	}

	return sockfd;
}

int HandleTcpClient(int confd)
{
	char tmpbuff[4096] = {0};
	ssize_t nsize = 0;

	memset(tmpbuff, 0, sizeof(tmpbuff));
	nsize = recv(confd, tmpbuff, sizeof(tmpbuff), 0);
	if(nsize == -1)
	{
		perror("fail to recv");
		return -1;
	}
	else if(nsize == 0)
	{
		return 0;
	}

	sprintf(tmpbuff, "%s ------echo", tmpbuff);
	nsize = send(confd, tmpbuff, strlen(tmpbuff), 0);
	if(nsize == -1)
	{
		perror("fail to send");
		return -1;
	}
	
	return nsize;

}

int AddFd(int epfd, int fd, uint32_t env)
{
	int ret = 0;
	struct epoll_event tmpenv;

	tmpenv.data.fd = fd;
	tmpenv.events = env;
	ret = epoll_ctl(epfd, EPOLL_CTL_ADD, fd, 
	if(ret == -1)
	{
		perror("fail to epoll_ctl");
		return -1;
	}

	return 0;
}

int DelFd(int epfd, int fd)
{
	int ret = 0;

	ret = epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL);
	if(ret == -1)
	{
		perror("fail to epoll_ctl");
		return -1;
	}

	return 0;
}


int main(void)
{
	int i = 0;
	int ret = 0;
	int nready = 0;
	int confd = 0;
	int sockfd = 0;
	struct epoll_event retenv[1024];
	int epfd = 0;
	
	epfd = epoll_create(1024);
	if(epfd == -1)
	{
		perror("fail to epoll_create");
		return -1;
	}

	sockfd = CreateListenSocket("192.168.1.155", 50000);
	
	AddFd(epfd, sockfd, EPOLLIN);

	while(1)
	{
		nready = epoll_wait(epfd, retenv, 1024, -1);
		if(nready == -1)
		{
			perror("fail to epoll");
			return -1;
		}
		
		for(i = 0; i < nready; i++)
		{
			if(retenv[i].data.fd == sockfd)
			{
				confd = accept(sockfd, NULL, NULL);
				if(confd == -1)
				{
					perror("fail to accept");
					DelFd(epfd, sockfd);
					close(sockfd);
					continue;
				}

				AddFd(epfd, confd, EPOLLIN);
			}
			else if(retenv[i].data.fd != sockfd)
			{
				ret = HandleTcpClient(retenv[i].data.fd);
				if(ret == -1)
				{
					fprintf(stderr, "handle tcp client failed!\n");
					DelFd(epfd, retenv[i].data.fd);
					close(retenv[i].data.fd);
					continue;
				}
				else if(ret == 0)
				{
					fprintf(stderr, "client disconnected!\n");
					DelFd(epfd, retenv[i].data.fd);
					close(retenv[i].data.fd);
					continue;
				}
			}
		}
	}
	
	close(epfd);
	close(sockfd);

	return 0;
}