Linux C/C++ reactor原理与实现

简介: Linux C/C++ reactor原理与实现

一、reactor原理

Reactor 释义“反应堆”,是一种事件驱动机制。

和普通函数调用的不同之处在于:应用程序不是主动的调用某个 API 完成处理,而是恰恰

相反,Reactor 逆置了事件处理流程,应用程序需要提供相应的接口并注册到 Reactor 上,

如果相应的时间发生,Reactor 将主动调用应用程序注册的接口,这些接口又称为“回调函

数”

Reactor 模式是处理并发 I/O 比较常见的一种模式,用于同步 I/O,中心思想是将所有要

处理的 I/O 事件注册到一个中心 I/O 多路复用器上,同时主线程/进程阻塞在多路复用器上;

一旦有 I/O 事件到来或是准备就绪(文件描述符或 socket 可读、写),多路复用器返回并将事

先注册的相应 I/O 事件分发到对应的处理器中。

Reactor架构模式允许事件驱动的应用通过多路分发的机制去处理来自不同客户端的多个请求。

Reactor可以理解为io管理集合,和多线程、多进程没有关系。但后续可以额外在reactor中引入多线程。

除了listenfd用accept处理,其他clientfd用recv和send处理

以前是通过epoll对io进行管理,而现在通过reactor对事件进行管理,可以把reactor理解为一种设计模式

深入理解Reactor 网络编程模型

二、代码部分

1.ntyreactor

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<sys/socket.h>
#include<sys/epoll.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<pthread.h>
#include<fcntl.h>
#include<errno.h>
#define BUFFER_LENGTH 4096
#define MAX_EPOLL_EVENTS 1024
#define SERVER_PORT 8888
typedef int NCALLBACK(int,int,void*);
struct ntyevent{
    int fd;
    int events;
    void* arg;
    int (*callback)(int fd,int events,void* arg);
    int status;
    char buffer[BUFFER_LENGTH];
    int length;
    long last_active;
};
struct ntyreactor{
    int epfd;
    ntyevent* events;
};
int recv_cb(int fd, int events, void *arg);
int send_cb(int fd, int events, void *arg);
void nty_event_set(ntyevent* ev,int fd,NCALLBACK callback,void* arg){
    ev->fd=fd;
    ev->callback=callback;
    ev->events=0;
    ev->arg=arg;
    ev->last_active=time(NULL);
}
int nty_event_add(int epfd,int events,ntyevent* ev){
    epoll_event ep_ev;
    ep_ev.data.ptr=ev;
    ep_ev.events = ev->events = events;
    int op;
    if(ev->status==1){
        op=EPOLL_CTL_MOD;
    }else{
        op=EPOLL_CTL_ADD;
        ev->status=1;
    }
    if(epoll_ctl(epfd,op,ev->fd,&ep_ev)<0){
        printf("epoll add faild\n");
        return -1;
    }
    return 0;
}
int nty_event_del(int epfd, struct ntyevent *ev) {
  struct epoll_event ep_ev = {0, {0}};
  if (ev->status != 1) {
    return -1;
  }
  ep_ev.data.ptr = ev;
  ev->status = 0;
  epoll_ctl(epfd, EPOLL_CTL_DEL, ev->fd, &ep_ev);
  return 0;
}
int recv_cb(int fd, int events, void *arg) {
  struct ntyreactor *reactor = (struct ntyreactor*)arg;
  struct ntyevent *ev = reactor->events+fd;
  int len = recv(fd, ev->buffer, BUFFER_LENGTH, 0);
  nty_event_del(reactor->epfd, ev);
  if (len > 0) {
    ev->length = len;
    ev->buffer[len] = '\0';
    printf("C[%d]:%s\n", fd, ev->buffer);
    nty_event_set(ev, fd, send_cb, reactor);
    nty_event_add(reactor->epfd, EPOLLOUT, ev);
  } else if (len == 0) {
    close(ev->fd);
    printf("[fd=%d] pos[%ld], closed\n", fd, ev-reactor->events);
  } else {
    close(ev->fd);
    printf("recv[fd=%d] error[%d]:%s\n", fd, errno, strerror(errno));
  }
  return len;
}
int send_cb(int fd, int events, void *arg) {
  struct ntyreactor *reactor = (struct ntyreactor*)arg;
  struct ntyevent *ev = reactor->events+fd;
  int len = send(fd, ev->buffer, ev->length, 0);
  if (len > 0) {
    printf("send[fd=%d], [%d]%s\n", fd, len, ev->buffer);
    nty_event_del(reactor->epfd, ev);//删掉又恢复,重置时间,(因为超时会断开连接)
    nty_event_set(ev, fd, recv_cb, reactor);
    nty_event_add(reactor->epfd, EPOLLIN, ev);
  } else {
    close(ev->fd);
    nty_event_del(reactor->epfd, ev);
    printf("send[fd=%d] error %s\n", fd, strerror(errno));
  }
  return len;
}
int accept_cb(int fd, int events, void *arg) {
  struct ntyreactor *reactor = (struct ntyreactor*)arg;
  if (reactor == NULL) return -1;
  struct sockaddr_in client_addr;
  socklen_t len = sizeof(client_addr);
  int clientfd;
  if ((clientfd = accept(fd, (struct sockaddr*)&client_addr, &len)) == -1) {
    if (errno != EAGAIN && errno != EINTR) {
    }
    printf("accept: %s\n", strerror(errno));
    return -1;
  }
  int i = 0;
  do {
    for (i = 3;i < MAX_EPOLL_EVENTS;i ++) {
      if (reactor->events[i].status == 0) {
        break;
      }
    }
    if (i == MAX_EPOLL_EVENTS) {
      printf("%s: max connect limit[%d]\n", __func__, MAX_EPOLL_EVENTS);
      break;
    }
    int flag = 0;
    if ((flag = fcntl(clientfd, F_SETFL, O_NONBLOCK)) < 0) {
      printf("%s: fcntl nonblocking failed, %d\n", __func__, MAX_EPOLL_EVENTS);
      break;
    }
    nty_event_set(&reactor->events[clientfd], clientfd, recv_cb, reactor);
    nty_event_add(reactor->epfd, EPOLLIN, &reactor->events[clientfd]);
  } while (0);
  printf("new connect [%s:%d][time:%ld], pos[%d]\n", 
    inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port), reactor->events[i].last_active, i);
  return 0;
}
int init_sockfd(uint16_t port){
    int sockfd=socket(AF_INET,SOCK_STREAM,0);
    fcntl(sockfd,F_SETFL,O_NONBLOCK);
    sockaddr_in server_addr;
    server_addr.sin_family=AF_INET;
  server_addr.sin_addr.s_addr=htonl(INADDR_ANY);
    server_addr.sin_port=htons(port);
    bind(sockfd,(sockaddr*)&server_addr,sizeof(sockaddr_in));
    if(listen(sockfd,20)<0){
        perror("listen");
    }
    return sockfd;
}
int ntyreactor_init(ntyreactor* reactor){
    if(reactor==NULL) return -1;
    memset(reactor,0,sizeof(ntyreactor));
    reactor->epfd=epoll_create(1);
    if(reactor->epfd<=0){
        // perror("create epfd in%s",__func__);
        close(reactor->epfd);
        return -2;
    }
    reactor->events=(ntyevent*)malloc(sizeof(ntyevent)*MAX_EPOLL_EVENTS);
    memset(reactor->events,0,sizeof(ntyevent)*MAX_EPOLL_EVENTS);
    if(reactor->events==NULL){
        // perror("create epfd in%s",__func__);
        close(reactor->epfd);
        return -3;
    }
}
int ntyreactor_destory(ntyreactor *reactor) {
  close(reactor->epfd);
  free(reactor->events);
}
int ntyreactor_addlistener(ntyreactor* reactor,int sockfd,NCALLBACK* acceptor){
    if(reactor==NULL) return -1;
    if(reactor->events==NULL) return -1;
    nty_event_set(&reactor->events[sockfd],sockfd,acceptor,reactor);
    nty_event_add(reactor->epfd,EPOLLIN,&reactor->events[sockfd]);
    return 0;
}
int ntyreactor_run(ntyreactor* reactor){
    if(reactor==NULL) return -1;
    if(reactor->epfd<0) return -1;
    if(reactor->events==NULL) return -1;
    epoll_event events[MAX_EPOLL_EVENTS+1];
    int checkpos=0;
    while(1){
        long now=time(NULL);
        for(int i=0;i<100;i++,checkpos++){
            if(checkpos==MAX_EPOLL_EVENTS){
                checkpos=0;
            }
            if(reactor->events[checkpos].status!=1){
                continue;
            }
            long duration = now - reactor->events[checkpos].last_active;
      if (duration >= 60) {
        close(reactor->events[checkpos].fd);
        printf("[fd=%d] timeout\n", reactor->events[checkpos].fd);
        nty_event_del(reactor->epfd, &reactor->events[checkpos]);
      }
        }
        int nready=epoll_wait(reactor->epfd,events,MAX_EPOLL_EVENTS,1000);
        if(nready<0) continue;
        for(int i=0;i<nready;i++){
            ntyevent* ev=(ntyevent*)events[i].data.ptr;
            if((events[i].events&EPOLLIN)&&(ev->events&EPOLLIN)){
                ev->callback(ev->fd,events[i].events,ev->arg);
            }
            if ((events[i].events & EPOLLOUT) && (ev->events & EPOLLOUT)) {
        ev->callback(ev->fd, events[i].events, ev->arg);
      }
        }
    }
}
int main(int argc,char** argv){
    uint16_t port=SERVER_PORT;
    if(argc==2){
        port=atoi(argv[1]);
    }
    int sockfd=init_sockfd(port);
    ntyreactor* reactor=(ntyreactor*)malloc(sizeof(ntyreactor));
    ntyreactor_init(reactor);
    ntyreactor_addlistener(reactor,sockfd,accept_cb);
    ntyreactor_run(reactor);
    ntyreactor_destory(reactor);
    close(sockfd);
    return 0;
}

2.ntyreactor(链表+数组 存储event的方式 )

服务端使用100个端口,Linux C/C++ 开发(学习笔记十三):百万并发的服务器实现

实现百万并发

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/epoll.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#define BUFFER_LENGTH   4096
#define MAX_EPOLL_EVENTS  1024
#define SERVER_PORT     8888
#define PORT_COUNT      100
typedef int NCALLBACK(int ,int, void*);
struct ntyevent {
  int fd;
  int events;
  void *arg;
  int (*callback)(int fd, int events, void *arg);
  int status;
  char buffer[BUFFER_LENGTH];
  int length;
  long last_active;
};
struct eventblock {
  struct eventblock *next;
  struct ntyevent *events;
};
struct ntyreactor {
  int epfd;
  int blkcnt;
  struct eventblock *evblk; //fd --> 100w
};
int recv_cb(int fd, int events, void *arg);
int send_cb(int fd, int events, void *arg);
struct ntyevent *ntyreactor_idx(struct ntyreactor *reactor, int sockfd);
void nty_event_set(struct ntyevent *ev, int fd, NCALLBACK callback, void *arg) {
  ev->fd = fd;
  ev->callback = callback;
  ev->events = 0;
  ev->arg = arg;
  ev->last_active = time(NULL);
  return ;
}
int nty_event_add(int epfd, int events, struct ntyevent *ev) {
  struct epoll_event ep_ev = {0, {0}};
  ep_ev.data.ptr = ev;
  ep_ev.events = ev->events = events;
  int op;
  if (ev->status == 1) {
    op = EPOLL_CTL_MOD;
  } else {
    op = EPOLL_CTL_ADD;
    ev->status = 1;
  }
  if (epoll_ctl(epfd, op, ev->fd, &ep_ev) < 0) {
    printf("event add failed [fd=%d], events[%d]\n", ev->fd, events);
    return -1;
  }
  return 0;
}
int nty_event_del(int epfd, struct ntyevent *ev) {
  struct epoll_event ep_ev = {0, {0}};
  if (ev->status != 1) {
    return -1;
  }
  ep_ev.data.ptr = ev;
  ev->status = 0;
  epoll_ctl(epfd, EPOLL_CTL_DEL, ev->fd, &ep_ev);
  return 0;
}
int recv_cb(int fd, int events, void *arg) {
  struct ntyreactor *reactor = (struct ntyreactor*)arg;
  struct ntyevent *ev = ntyreactor_idx(reactor, fd);
  int len = recv(fd, ev->buffer, BUFFER_LENGTH , 0); // 
  nty_event_del(reactor->epfd, ev);
  if (len > 0) {
    ev->length = len;
    ev->buffer[len] = '\0';
    printf("C[%d]:%s\n", fd, ev->buffer);
    nty_event_set(ev, fd, send_cb, reactor);
    nty_event_add(reactor->epfd, EPOLLOUT, ev);
  } else if (len == 0) {
    close(ev->fd);
    //printf("[fd=%d] pos[%ld], closed\n", fd, ev-reactor->events);
  } else {
    close(ev->fd);
    printf("recv[fd=%d] error[%d]:%s\n", fd, errno, strerror(errno));
  }
  return len;
}
int send_cb(int fd, int events, void *arg) {
  struct ntyreactor *reactor = (struct ntyreactor*)arg;
  struct ntyevent *ev = ntyreactor_idx(reactor, fd);
  int len = send(fd, ev->buffer, ev->length, 0);
  if (len > 0) {
    printf("send[fd=%d], [%d]%s\n", fd, len, ev->buffer);
    nty_event_del(reactor->epfd, ev);
    nty_event_set(ev, fd, recv_cb, reactor);
    nty_event_add(reactor->epfd, EPOLLIN, ev);
  } else {
    close(ev->fd);
    nty_event_del(reactor->epfd, ev);
    printf("send[fd=%d] error %s\n", fd, strerror(errno));
  }
  return len;
}
int accept_cb(int fd, int events, void *arg) {
  struct ntyreactor *reactor = (struct ntyreactor*)arg;
  if (reactor == NULL) return -1;
  struct sockaddr_in client_addr;
  socklen_t len = sizeof(client_addr);
  int clientfd;
  if ((clientfd = accept(fd, (struct sockaddr*)&client_addr, &len)) == -1) {
    if (errno != EAGAIN && errno != EINTR) {
    }
    printf("accept: %s\n", strerror(errno));
    return -1;
  }
  int flag = 0;
  if ((flag = fcntl(clientfd, F_SETFL, O_NONBLOCK)) < 0) {
    printf("%s: fcntl nonblocking failed, %d\n", __func__, MAX_EPOLL_EVENTS);
    return -1;
  }
  struct ntyevent *event = ntyreactor_idx(reactor, clientfd);
  nty_event_set(event, clientfd, recv_cb, reactor);
  nty_event_add(reactor->epfd, EPOLLIN, event);
  printf("new connect [%s:%d], pos[%d]\n", 
    inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port), clientfd);
  return 0;
}
int init_sock(short port) {
  int fd = socket(AF_INET, SOCK_STREAM, 0);
  fcntl(fd, F_SETFL, O_NONBLOCK);
  struct sockaddr_in server_addr;
  memset(&server_addr, 0, sizeof(server_addr));
  server_addr.sin_family = AF_INET;
  server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
  server_addr.sin_port = htons(port);
  bind(fd, (struct sockaddr*)&server_addr, sizeof(server_addr));
  if (listen(fd, 20) < 0) {
    printf("listen failed : %s\n", strerror(errno));
  }
  return fd;
}
int ntyreactor_alloc(struct ntyreactor *reactor) {
  if (reactor == NULL) return -1;
  if (reactor->evblk == NULL) return -1;
  struct eventblock *blk = reactor->evblk;
  while (blk->next != NULL) {
    blk = blk->next;
  }
  struct ntyevent *evs = (struct ntyevent*)malloc((MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
  if (evs == NULL) {
    printf("ntyreactor_alloc ntyevents failed\n");
    return -2;
  }
  memset(evs, 0, (MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
  struct eventblock *block = (struct eventblock *)malloc(sizeof(struct eventblock));
  if (block == NULL) {
    printf("ntyreactor_alloc eventblock failed\n");
    return -2;
  }
  memset(block, 0, sizeof(struct eventblock));
  block->events = evs;
  block->next = NULL;
  blk->next = block;
  reactor->blkcnt ++; //
  return 0;
}
struct ntyevent *ntyreactor_idx(struct ntyreactor *reactor, int sockfd) {
  int blkidx = sockfd / MAX_EPOLL_EVENTS;
  while (blkidx >= reactor->blkcnt) {
    ntyreactor_alloc(reactor);
  }
  int i = 0;
  struct eventblock *blk = reactor->evblk;
  while(i ++ < blkidx && blk != NULL) {
    blk = blk->next;
  }
  return &blk->events[sockfd % MAX_EPOLL_EVENTS];
}
int ntyreactor_init(struct ntyreactor *reactor) {
  if (reactor == NULL) return -1;
  memset(reactor, 0, sizeof(struct ntyreactor));
  reactor->epfd = epoll_create(1);
  if (reactor->epfd <= 0) {
    printf("create epfd in %s err %s\n", __func__, strerror(errno));
    return -2;
  }
  struct ntyevent *evs = (struct ntyevent*)malloc((MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
  if (evs == NULL) {
    printf("ntyreactor_alloc ntyevents failed\n");
    return -2;
  }
  memset(evs, 0, (MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
  struct eventblock *block = (struct eventblock *)malloc(sizeof(struct eventblock));
  if (block == NULL) {
    printf("ntyreactor_alloc eventblock failed\n");
    return -2;
  }
  memset(block, 0, sizeof(struct eventblock));
  block->events = evs;
  block->next = NULL;
  reactor->evblk = block;
  reactor->blkcnt = 1;
  return 0;
}
int ntyreactor_destory(struct ntyreactor *reactor) {
  close(reactor->epfd);
  //free(reactor->events);
  struct eventblock *blk = reactor->evblk;
  struct eventblock *blk_next = NULL;
  while (blk != NULL) {
    blk_next = blk->next;
    free(blk->events);
    free(blk);
    blk = blk_next;
  }
  return 0;
}
int ntyreactor_addlistener(struct ntyreactor *reactor, int sockfd, NCALLBACK *acceptor) {
  if (reactor == NULL) return -1;
  if (reactor->evblk == NULL) return -1;
  //reactor->evblk->events[sockfd];
  struct ntyevent *event = ntyreactor_idx(reactor, sockfd);
  nty_event_set(event, sockfd, acceptor, reactor);
  nty_event_add(reactor->epfd, EPOLLIN, event);
  return 0;
}
int ntyreactor_run(struct ntyreactor *reactor) {
  if (reactor == NULL) return -1;
  if (reactor->epfd < 0) return -1;
  if (reactor->evblk == NULL) return -1;
  struct epoll_event events[MAX_EPOLL_EVENTS+1];
  int checkpos = 0, i;
  while (1) {
/*
    long now = time(NULL);
    for (i = 0;i < 100;i ++, checkpos ++) {
      if (checkpos == MAX_EPOLL_EVENTS) {
        checkpos = 0;
      }
      if (reactor->events[checkpos].status != 1) {
        continue;
      }
      long duration = now - reactor->events[checkpos].last_active;
      if (duration >= 60) {
        close(reactor->events[checkpos].fd);
        printf("[fd=%d] timeout\n", reactor->events[checkpos].fd);
        nty_event_del(reactor->epfd, &reactor->events[checkpos]);
      }
    }
*/
    int nready = epoll_wait(reactor->epfd, events, MAX_EPOLL_EVENTS, 1000);
    if (nready < 0) {
      printf("epoll_wait error, exit\n");
      continue;
    }
    for (i = 0;i < nready;i ++) {
      struct ntyevent *ev = (struct ntyevent*)events[i].data.ptr;
      if ((events[i].events & EPOLLIN) && (ev->events & EPOLLIN)) {
        ev->callback(ev->fd, events[i].events, ev->arg);
      }
      if ((events[i].events & EPOLLOUT) && (ev->events & EPOLLOUT)) {
        ev->callback(ev->fd, events[i].events, ev->arg);
      }
    }
  }
}
// 3, 6w, 1, 100 == 
// <remoteip, remoteport, localip, localport>
int main(int argc, char *argv[]) {
  unsigned short port = SERVER_PORT; // listen 8888
  if (argc == 2) {
    port = atoi(argv[1]);
  }
  struct ntyreactor *reactor = (struct ntyreactor*)malloc(sizeof(struct ntyreactor));
  ntyreactor_init(reactor);
  int i = 0;
  int sockfds[PORT_COUNT] = {0};
  for (i = 0;i < PORT_COUNT;i ++) {
    sockfds[i] = init_sock(port+i);
    ntyreactor_addlistener(reactor, sockfds[i], accept_cb);
  }
  ntyreactor_run(reactor);
  ntyreactor_destory(reactor);
  for (i = 0;i < PORT_COUNT;i ++) {
    close(sockfds[i]);
  }
  free(reactor);
  return 0;
}


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