epoll server

参考：epoll server/client以及tcp close wait状态 - 知乎

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define IP_ADDRESS  "127.0.0.1"
#define LISTENQ 20

static void set_nonblocking(const int sock)
{
    int opts;
    opts = fcntl(sock,F_GETFL);
    if(opts < 0)
    {
        perror("fcntl(sock,GETFL)");
        exit(1);
    }
    opts = opts|O_NONBLOCK;
    if(fcntl(sock, F_SETFL, opts)<0)
    {
        perror("fcntl(sock,SETFL,opts)");
        exit(1);
    }
}

static void add_event(int epoll_fd, int fd, int state)
{
    struct epoll_event ev;
    ev.events = state;
    ev.data.fd = fd;
    epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev);
}

static void delete_event(int epoll_fd,int fd,int state)
{
    struct epoll_event ev;
    ev.events = state;
    ev.data.fd = fd;
    epoll_ctl(epoll_fd,EPOLL_CTL_DEL,fd,&ev);
}

static void modify_event(int epoll_fd,int fd,int state)
{
    struct epoll_event ev;
    ev.events = state;
    ev.data.fd = fd;
    epoll_ctl(epoll_fd,EPOLL_CTL_MOD,fd,&ev);
}

static int bind_socket(const char* ip, int port)
{
    int  listen_fd;
    struct sockaddr_in servaddr;
    listen_fd = socket(AF_INET, SOCK_STREAM, 0);
    if(listen_fd == -1)
    {
        perror("socket error:");
        exit(1);
    }
	
	int32_t on = 1;
    setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, (const char *)&on, sizeof(on));

    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    inet_pton(AF_INET,ip,&servaddr.sin_addr);
    servaddr.sin_port = htons(port);
    if(bind(listen_fd,(struct sockaddr*)&servaddr,sizeof(servaddr)) == -1)
    {
        perror("bind error: ");
        exit(1);
    }
	
	printf("bind ip:%s port:%d.err:%s\r\n", inet_ntoa(servaddr.sin_addr), ntohs(servaddr.sin_port), strerror(errno));

    return listen_fd;
}

static void accept_process(int epoll_fd, int listen_fd)
{
    int client_fd;
    struct sockaddr_in cliaddr;
    socklen_t  cliaddrlen = sizeof(cliaddr);

    client_fd = accept(listen_fd, (struct sockaddr*)&cliaddr, &cliaddrlen);
    if (client_fd == -1)
    {
		perror("accpet error:");
	}
    else
    {
        printf("accept a new client, ip:%s port:%d\n",inet_ntoa(cliaddr.sin_addr), cliaddr.sin_port);
		set_nonblocking(client_fd);
        //添加一个客户描述符和事件
        add_event(epoll_fd, client_fd, EPOLLIN);
    }
}

static void read_socket(int epoll_fd, int fd, char *buf, int buf_size)
{
    int nread;
	
	printf("[%s][%d] read fd:%d start\r\n", __func__, __LINE__, fd);
	while((nread=read(fd, buf, buf_size-1)) > 0)
	{
		buf[nread] = '\0';
		printf("[%s][%d] read:%s\r\n", __func__, __LINE__, buf);
	};
	
	printf("[%s][%d] read fd:%d end\r\n", __func__, __LINE__, fd);
	printf("[%s][%d] read len=%d. err:%s\r\n", __func__, __LINE__, nread, strerror(errno));
	
	if(nread == 0)
	{ // 对端关闭
		printf("[%s][%d] %d closed.\r\n", __func__, __LINE__, fd);
		close(fd);
		delete_event(epoll_fd, fd, EPOLLIN);
	}
}

int main (int argc, char * argv[])
{
	int listen_fd;
	if (2 != argc)
    {
        printf("Usage:%s portnumber\r\n", argv[0]);
        return 1;
    }
	
    listen_fd = bind_socket(IP_ADDRESS, atoi(argv[1]));
	
    listen(listen_fd, LISTENQ);
	
	int epoll_fd;
    struct epoll_event events[10];
    int nfds, i, fd;
    char buf[20];
	
    //创建一个描述符
    epoll_fd = epoll_create1(EPOLL_CLOEXEC); // EPOLL_CLOEXEC：这是这个参数唯一的有效值，如果这个参数设置为这个。那么当进程替换映像的时候会关闭这个文件描述符，这样新的映像中就无法对这个文件描述符操作，适用于多进程编程+映像替换的环境里
    //添加监听描述符事件
    add_event(epoll_fd,listen_fd, EPOLLIN); // 将listen_fd添加到epoll_fd内 EPOLLIN ：表示对应的文件描述符可以读（包括对端SOCKET正常关闭）；
	
    for ( ; ; )
    {
        nfds = epoll_wait(epoll_fd, events, sizeof(events)/sizeof(events[0]), 1000);
		
		for(i=0; i

使用网络调试助手作为tcp client测试