多路IO复用--epoll实现

比眉伴天荒 2022-01-09 19:11 323阅读 0赞

### 文章目录 ###

> epoll事件有两种模型：  
> Edge Triggered(ET) 边缘触发，只有数据到来才触发，不管缓存区中是否还有数据  
> Level Triggered(LT) 水平触发，只要有数据就会触发

server.c

#include <stdlib.h>
    #include <stdio.h>
    #include <string.h>
    #include <unistd.h>
    #include <sys/socket.h>
    #include <sys/types.h>
    #include <sys/epoll.h>
    #include <errno.h>
    #include <arpa/inet.h>
    #include <fcntl.h>
    
    #define SERV_PORT  6666
    #define MAX_LINE   1024
    #define MAX_CONN   50000
    
    int main()
    {
        
    	char buf[MAX_LINE];
    	int listenfd = Socket(AF_INET,SOCK_STREAM,0);
    	int opt = 1;
    	setsockopt(listenfd,SOL_SOCKET,SO_REUSEPORT,&opt,sizeof(opt));//设置端口复用
    	setsockopt(listenfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));//设置地址复用
    	
    	struct sockaddr_in servaddr;
    	bzero(&servaddr,sizeof(servaddr));
    	servaddr.sin_family = AF_INET;
    	servaddr.sin_port = htons(SERV_PORT);
    	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    	Bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
    	Listen(listenfd, 128);
    
    	int efd = epoll_create(1);//创建红黑树树根
    	if(efd < 0)
    	{
        
    		perr_exit("epoll_create");
    		return -1;
    	}
    	
    	struct epoll_event event;
    	event.events = EPOLLIN;
    	event.data.fd = listenfd;
    	int res = epoll_ctl(efd,EPOLL_CTL_ADD,listenfd,&event);
    	if(res < 0)
    	{
        
    		perr_exit("epoll_ctl");
    		Close(listenfd);
    		return -1;
    	}
    	while (1)
    	{
        
    		struct epoll_event revents[MAX_CONN + 1];
    		int nready = epoll_wait(efd,revents,MAX_CONN + 1,-1);
    		if(nready < 0)
    		{
        
    			perr_exit("epoll_wait");
    			break;
    		}
    		int i = 0;
    		for(i = 0;i < nready;i++)
    		{
        
    			if((revents[i].events & EPOLLIN)&&(revents[i].data.fd == listenfd))
    			{
        
    				struct sockaddr_in clientaddr;
    				socklen_t clientsize = sizeof(clientaddr);
    				bzero(&clientaddr,clientsize);
    				int connfd = Accept(listenfd, (struct sockaddr *)&clientaddr, &clientsize);
    				int flag = fcntl(connfd,F_GETFL);
    				flag |= O_NONBLOCK;
    				fcntl(connfd,F_SETFL,flag);
    				char buf[16];
    				printf("recvfrom %s at %d\n",inet_ntop(AF_INET,&clientaddr.sin_addr,buf,sizeof(buf)),ntohs(clientaddr.sin_port));
    				struct epoll_event ev;
    				ev.events = EPOLLIN | EPOLLET;	//设置边沿触发
    				//ev.events = EPOLLIN ;				//默认水平触发
    				ev.data.fd = connfd;
    				res = epoll_ctl(efd,EPOLL_CTL_ADD,connfd,&ev);
    				if(res < 0)
    				{
        
    					perr_exit("epoll_ctl");
    					break;
    				}
    			}
    			else
    			{
        
    				if(revents[i].events & EPOLLIN)
    				{
        
    					while(1)
    					{
        
    						memset(buf,0,sizeof(buf));
    						int n = Read(revents[i].data.fd, buf, sizeof(buf));
    						if(n == 0)//对端关闭
    						{
        
    							printf("client[%d] is closed\n",revents[i].data.fd);
    							res = epoll_ctl(efd,EPOLL_CTL_DEL,revents[i].data.fd,NULL);//将该文件描述符从红黑树摘除
    							if(res < 0)
    							{
        
    								perr_exit("read");
    							}
    							Close(revents[i].data.fd);                  //关闭与该客户端的链接
    						}
    						else if(n < 0)
    						{
        
    							if(errno != EWOULDBLOCK && errno != EINTR)
    							{
        
    								perr_exit("read");
    								res = epoll_ctl(efd, EPOLL_CTL_DEL, revents[i].data.fd, NULL);
                        			Close(revents[i].data.fd);
    							}
    						}
    						else
    						{
        
    							printf("len = %d,buf = %s\n",n,buf);
    							buf[n] = '\n';
    							Write(revents[i].data.fd, buf, n + 1);
    						}
    					}
    				}
    			}
    		}
    	}
    	Close(listenfd);
        Close(efd);
    	return 0;
    }