C 语言

关注公众号 jb51net

关闭
首页 > 软件编程 > C 语言 > C++ reactor并发服务器

C++实现基于reactor的百万级并发服务器

作者:humanGetup

本文介绍了基于Reactor模式的百万级并发服务器,使用epoll进行高效I/O多路复用,支持多个端口的监听,并通过回调机制处理每个连接的接收和发送操作,需要的朋友可以参考下

一、基于 Reactor 模式的百万级并发服务器是什么?

基于 Reactor 模式的百万级并发服务器 是指一个能够高效地处理百万级并发连接的服务器架构,它通常使用 Reactor 设计模式来管理大量的客户端连接。Reactor 模式是一种事件驱动模式,主要用于 I/O 多路复用,使得服务器可以在单一线程或少量线程中高效地处理大量并发连接,避免了传统的多线程模型中线程开销和上下文切换的性能瓶颈。

二、源码展示

#include <errno.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
#include <poll.h>
#include <sys/epoll.h>
#include <errno.h>
#include <sys/time.h>
 
 
 
#define BUFFER_LENGTH		1024
#define CONNECTION_SIZE	    1048576
 
#define MAX_PORTS			20
 
#define TIME_SUB_MS(tv1, tv2)  ((tv1.tv_sec - tv2.tv_sec) * 1000 + (tv1.tv_usec - tv2.tv_usec) / 1000)
 
typedef int (*RCALLBACK)(int fd);
 
int accept_cb(int fd);
int recv_cb(int fd);
int send_cb(int fd);
 
int epfd = 0;
struct timeval begin;
 
 
struct conn {
	int fd;
 
	char rbuffer[BUFFER_LENGTH];
	int rlength;
 
	char wbuffer[BUFFER_LENGTH];
	int wlength;
 
	RCALLBACK send_callback;
 
	union {
		RCALLBACK recv_callback;
		RCALLBACK accept_callback;
	} r_action;
 
 
};
 
//fd做下标
struct conn conn_list[CONNECTION_SIZE] = {0};
 
int set_event(int fd, int event, int flag) {
 
	if (flag) {  // non-zero add
 
		struct epoll_event ev;
		ev.events = event;
		ev.data.fd = fd;
		epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev);
 
	} else {  // zero mod
 
		struct epoll_event ev;
		ev.events = event;
		ev.data.fd = fd;
		epoll_ctl(epfd, EPOLL_CTL_MOD, fd, &ev);
		
	}
	
 
}
 
 
int event_register(int fd, int event) {
 
	if (fd < 0) return -1;
 
	conn_list[fd].fd = fd;
	conn_list[fd].r_action.recv_callback = recv_cb;
	conn_list[fd].send_callback = send_cb;
 
	memset(conn_list[fd].rbuffer, 0, BUFFER_LENGTH);
	conn_list[fd].rlength = 0;
 
	memset(conn_list[fd].wbuffer, 0, BUFFER_LENGTH);
	conn_list[fd].wlength = 0;
 
	set_event(fd, event, 1);
}
 
 
// listenfd(sockfd) --> EPOLLIN --> accept_cb
int accept_cb(int fd) {
 
	struct sockaddr_in  clientaddr;
	socklen_t len = sizeof(clientaddr);
 
	int clientfd = accept(fd, (struct sockaddr*)&clientaddr, &len);
	//printf("accept finshed: %d\n", clientfd);
	if (clientfd < 0) {
		printf("accept errno: %d --> %s\n", errno, strerror(errno));
		return -1;
	}
	
	
	event_register(clientfd, EPOLLIN);  // | EPOLLET	
 
	if ((clientfd % 1000) == 0) {	
		
		struct timeval current;		
		gettimeofday(&current, NULL);	
		
		int time_used = TIME_SUB_MS(current, begin);		
		memcpy(&begin, &current, sizeof(struct timeval));	
		
		printf("accept finshed: %d, time_used: %d\n", clientfd, time_used);	
 
	}
	
	return 0;
}
 
int recv_cb(int fd) {
 
	memset(conn_list[fd].rbuffer, 0, BUFFER_LENGTH );
	int count = recv(fd, conn_list[fd].rbuffer, BUFFER_LENGTH, 0);
	if (count == 0) { // disconnect
		printf("client disconnect: %d\n", fd);
		close(fd);
 
		epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL); // unfinished
 
		return 0;
	} else if (count < 0) { // 
 
		printf("count: %d, errno: %d, %s\n", count, errno, strerror(errno));
		close(fd);
		epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL);
 
		return 0;
	}
 
	conn_list[fd].rlength = count;
	//printf("RECV: %s\n", conn_list[fd].rbuffer);
 
    // echo
	conn_list[fd].wlength = conn_list[fd].rlength;
	memcpy(conn_list[fd].wbuffer, conn_list[fd].rbuffer, conn_list[fd].wlength);
 
 
	set_event(fd, EPOLLOUT, 0);
 
	return count;
}
 
int send_cb(int fd) {
 
	int count = 0;
 
	if (conn_list[fd].wlength != 0) {
		count = send(fd, conn_list[fd].wbuffer, conn_list[fd].wlength, 0);
	}
	
	set_event(fd, EPOLLIN, 0);
 
	return count;
}
 
 
int init_server(unsigned short port) {
 
	int sockfd = socket(AF_INET, SOCK_STREAM, 0);
 
	struct sockaddr_in servaddr;
	servaddr.sin_family = AF_INET;
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY); // 0.0.0.0
	servaddr.sin_port = htons(port); // 0-1023, 
 
	if (-1 == bind(sockfd, (struct sockaddr*)&servaddr, sizeof(struct sockaddr))
) {
		printf("bind failed: %s\n", strerror(errno));
	}
 
	listen(sockfd, 10);
	//printf("listen finshed: %d\n", sockfd); // 3 
 
	return sockfd;
 
}
 
int main() {
 
	unsigned short port = 2000;
    
    epfd = epoll_create(1);
    
    int i = 0;	
 
	for (i = 0;i < MAX_PORTS;i ++) {		
		
		int sockfd = init_server(port + i);				
 
		conn_list[sockfd].fd = sockfd;		
		conn_list[sockfd].r_action.recv_callback = accept_cb;				
		set_event(sockfd, EPOLLIN, 1);	
 
	}
 
	gettimeofday(&begin, NULL);
    
    while (1) { // mainloop
 
		struct epoll_event events[1024] = {0};
		int nready = epoll_wait(epfd, events, 1024, -1);
 
		int i = 0;
		for (i = 0;i < nready;i ++) {
 
			int connfd = events[i].data.fd;
 
			if (events[i].events & EPOLLIN) {
				conn_list[connfd].r_action.recv_callback(connfd);
			} 
 
			if (events[i].events & EPOLLOUT) {
				conn_list[connfd].send_callback(connfd);
			}
 
 
 
 
		}
 
	}
 
 
}
 

三、代码分析

这段代码是一个简单的基于 epoll 的 I/O 多路复用网络服务器实现。它的核心功能是监听多个端口,接受来自客户端的连接,并且通过回调机制处理接收到的数据和发送的数据。它利用了 epoll 的高效事件驱动模型来处理多个并发连接。

1.定义常量与结构体

#define BUFFER_LENGTH        1024
#define CONNECTION_SIZE      1048576
#define MAX_PORTS            20
 
#define TIME_SUB_MS(tv1, tv2)  ((tv1.tv_sec - tv2.tv_sec) * 1000 + (tv1.tv_usec - tv2.tv_usec) / 1000)
 
typedef int (*RCALLBACK)(int fd);
struct conn {
    int fd;
    char rbuffer[BUFFER_LENGTH];
    int rlength;
    char wbuffer[BUFFER_LENGTH];
    int wlength;
    RCALLBACK send_callback;
    union {
        RCALLBACK recv_callback;
        RCALLBACK accept_callback;
    } r_action;
};

2.set_event 函数

int set_event(int fd, int event, int flag) {
    if (flag) {  // non-zero add
        struct epoll_event ev;
        ev.events = event;
        ev.data.fd = fd;
        epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev);
    } else {  // zero mod
        struct epoll_event ev;
        ev.events = event;
        ev.data.fd = fd;
        epoll_ctl(epfd, EPOLL_CTL_MOD, fd, &ev);
    }
}

3.event_register 函数

int event_register(int fd, int event) {
    if (fd < 0) return -1;
    conn_list[fd].fd = fd;
    conn_list[fd].r_action.recv_callback = recv_cb;
    conn_list[fd].send_callback = send_cb;
    memset(conn_list[fd].rbuffer, 0, BUFFER_LENGTH);
    conn_list[fd].rlength = 0;
    memset(conn_list[fd].wbuffer, 0, BUFFER_LENGTH);
    conn_list[fd].wlength = 0;
    set_event(fd, event, 1);
}

4.连接接收与发送回调函数

int accept_cb(int fd) {
    struct sockaddr_in clientaddr;
    socklen_t len = sizeof(clientaddr);
    int clientfd = accept(fd, (struct sockaddr*)&clientaddr, &len);
    if (clientfd < 0) {
        printf("accept errno: %d --> %s\n", errno, strerror(errno));
        return -1;
    }
    event_register(clientfd, EPOLLIN);
    if ((clientfd % 1000) == 0) {
        struct timeval current;
        gettimeofday(&current, NULL);
        int time_used = TIME_SUB_MS(current, begin);
        memcpy(&begin, &current, sizeof(struct timeval));
        printf("accept finshed: %d, time_used: %d\n", clientfd, time_used);
    }
    return 0;
}

accept_cb:该函数处理新的客户端连接。

int recv_cb(int fd) {
    memset(conn_list[fd].rbuffer, 0, BUFFER_LENGTH);
    int count = recv(fd, conn_list[fd].rbuffer, BUFFER_LENGTH, 0);
    if (count == 0) {
        printf("client disconnect: %d\n", fd);
        close(fd);
        epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL);
        return 0;
    } else if (count < 0) {
        printf("count: %d, errno: %d, %s\n", count, errno, strerror(errno));
        close(fd);
        epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL);
        return 0;
    }
    conn_list[fd].rlength = count;
    conn_list[fd].wlength = conn_list[fd].rlength;
    memcpy(conn_list[fd].wbuffer, conn_list[fd].rbuffer, conn_list[fd].wlength);
    set_event(fd, EPOLLOUT, 0);
    return count;
}

recv_cb:该函数处理从客户端接收到的数据。

int send_cb(int fd) {
    int count = 0;
    if (conn_list[fd].wlength != 0) {
        count = send(fd, conn_list[fd].wbuffer, conn_list[fd].wlength, 0);
    }
    set_event(fd, EPOLLIN, 0);
    return count;
}

send_cb:该函数处理数据发送。

5.init_server 函数

int init_server(unsigned short port) {
    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    struct sockaddr_in servaddr;
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(port);
    if (-1 == bind(sockfd, (struct sockaddr*)&servaddr, sizeof(struct sockaddr))) {
        printf("bind failed: %s\n", strerror(errno));
    }
    listen(sockfd, 10);
    return sockfd;
}

init_server 函数用于初始化服务器:

6.main 函数

int main() {
    unsigned short port = 2000;
    epfd = epoll_create(1);
    int i = 0;
    for (i = 0; i < MAX_PORTS; i++) {
        int sockfd = init_server(port + i);
        conn_list[sockfd].fd = sockfd;
        conn_list[sockfd].r_action.recv_callback = accept_cb;
        set_event(sockfd, EPOLLIN, 1);
    }
 
    gettimeofday(&begin, NULL);
 
    while (1) {
        struct epoll_event events[1024] = {0};
        int nready = epoll_wait(epfd, events, 1024, -1);
        int i = 0;
        for (i = 0; i < nready; i++) {
            int connfd = events[i].data.fd;
            if (events[i].events & EPOLLIN) {
                conn_list[connfd].r_action.recv_callback(connfd);
            }
            if (events[i].events & EPOLLOUT) {
                conn_list[connfd].send_callback(connfd);
            }
        }
    }
}

main 函数执行以下操作:

7.总结:

该程序使用 epoll 进行高效的多路复用网络 I/O,支持多个端口的监听。它使用回调机制来处理每个连接的接收和发送操作。程序为每个连接分配一个结构体,管理其缓冲区和回调函数,通过 epoll 处理异步 I/O 操作。

四、常见问题

1.默认的open files数量限制为1024

解决方案:

输入

ulimit -a

可查看open files

可以看到现在最多建立1024个连接

输入

ulimit -n 1048576

可修改open files

此时再输入

ulimit -a

可以看到:

将服务端和客户端的open files都设置为1048576,这是实现百万级并发的基础

2.不能分配地址

原因是:五元组的数量不够

五元组(sip,dip, sport, dport, proto)源ip(本地ip),目的ip(远程ip),源端口(本机端口),目的端口(远程端口),协议

eg:

192.168.127.128sip

192.168.127.129dip

建立连接27999个,占用端口1024-29,023

解决方案:建立多个server(提供sport)

对应main函数这段代码:

#define MAX_PORTS			20
 
int i = 0;	
 
	for (i = 0;i < MAX_PORTS;i ++) {		
		
		int sockfd = init_server(port + i);				
 
		conn_list[sockfd].fd = sockfd;		
		conn_list[sockfd].r_action.recv_callback = accept_cb;				
		set_event(sockfd, EPOLLIN, 1);	
 
	}

这个问题解决以前,服务端代码是只调用了一个端口的

3.系统版本导致的问题

这个版本的ubuntu在处理网络高并发时存在问题

解决方案:

修改配置文件 /etc/sysctl.conf,在这个文件的结尾加上

net.ipv4.tcp_syn_retries = 5
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_mem = 262144 786432 786432
net.ipv4.tcp_wmem = 1024 1024 2048
net.ipv4.tcp_rmem = 1024 1024 2048
fs.file-max = 1048576
net.nf_conntrack_max = 1048576
net.netfilter.nf_conntrack_tcp_timeout_established = 1200

Linux终端中输入

sudo vim /etc/sysctl.conf

进入配置文件,并将上面的内容输入,然后按 ESC -> ctrl + : -> wq 保存并退出

再按照下图执行四条指令

若输出如图,则说明问题已经解决。

记得将服务端和客户端都按照以上方法配置

五、百万级并发结果展示

总结

本文基于reactor设计模式,实现了服务器百万级并发

以上就是C++实现基于reactor的百万级并发服务器的详细内容,更多关于C++ reactor并发服务器的资料请关注脚本之家其它相关文章!

您可能感兴趣的文章:
阅读全文