epoll



//  
// a simple echo server using epoll in linux 
//  
// 2009-11-05 
// 2013-03-22:修改了几个问题，1是/n格式问题，2是去掉了原代码不小心加上的ET模式;
// 本来只是简单的示意程序，决定还是加上 recv/send时的buffer偏移
// by sparkling 
//  
#include <sys/socket.h> 
#include <sys/epoll.h> 
#include <netinet/in.h> 
#include <arpa/inet.h> 
#include <fcntl.h> 
#include <unistd.h> 
#include <stdio.h> 
#include <errno.h> 
#include <strings.h>

#ifdef __cplusplus
#if __cplusplus
extern "C" {
#endif
#endif

#define MAX_EVENTS 500 
struct myevent_s 
{ 
    int fd; 
    void (*call_back)(int fd, int events, void *arg); 
    int events; 
    void *arg; 
    int status; // 1: in epoll wait list, 0 not in 
    char buff[128]; // recv data buffer 
    int len, s_offset; 
    long last_active; // last active time 
}; 
// set event 
void EventSet(struct myevent_s *ev, int fd, void (*call_back)(int, int, void*), void *arg) 
{ 
    ev->fd = fd; 
    ev->call_back = call_back; 
    ev->events = 0; 
    ev->arg = arg; 
    ev->status = 0;
    bzero(ev->buff, sizeof(ev->buff));
    ev->s_offset = 0; 
    ev->len = 0;
    ev->last_active = time(NULL); 
} 
// add/mod an event to epoll 
void EventAdd(int epollFd, int events,struct myevent_s *ev) 
{ 
    struct epoll_event epv = {0, {0}}; 
    int op; 
    epv.data.ptr = ev; 
    epv.events = ev->events = events; 
    if(ev->status == 1){ 
        op = EPOLL_CTL_MOD; 
    } 
    else{ 
        op = EPOLL_CTL_ADD; 
        ev->status = 1; 
    } 
    if(epoll_ctl(epollFd, op, ev->fd, &epv) < 0) 
        printf("Event Add failed[fd=%d], evnets[%d]\n", ev->fd, events); 
    else 
        printf("Event Add OK[fd=%d], op=%d, evnets[%0X]\n", ev->fd, op, events); 
} 
// delete an event from epoll 
void EventDel(int epollFd,struct myevent_s *ev) 
{ 
    struct epoll_event epv = {0, {0}}; 
    if(ev->status != 1) return; 
    epv.data.ptr = ev; 
    ev->status = 0;
    epoll_ctl(epollFd, EPOLL_CTL_DEL, ev->fd, &epv); 
} 
int g_epollFd; 
struct myevent_s g_Events[MAX_EVENTS+1]; // g_Events[MAX_EVENTS] is used by listen fd 
void RecvData(int fd, int events, void *arg); 
void SendData(int fd, int events, void *arg); 
// accept new connections from clients 
void AcceptConn(int fd, int events, void *arg) 
{ 
    struct sockaddr_in sin; 
    socklen_t len = sizeof(struct sockaddr_in); 
    int nfd, i; 
    // accept 
    if((nfd = accept(fd, (struct sockaddr*)&sin, &len)) == -1) 
    { 
        if(errno != EAGAIN && errno != EINTR) 
        { 
        }
        printf("%s: accept, %d", __func__, errno); 
        return; 
    } 
    do 
    { 
        for(i = 0; i < MAX_EVENTS; i++) 
        { 
            if(g_Events[i].status == 0) 
            { 
                break; 
            } 
        } 
        if(i == MAX_EVENTS) 
        { 
            printf("%s:max connection limit[%d].", __func__, MAX_EVENTS); 
            break; 
        } 
        // set nonblocking
        int iret = 0;
        if((iret = fcntl(nfd, F_SETFL, O_NONBLOCK)) < 0)
        {
            printf("%s: fcntl nonblocking failed:%d", __func__, iret);
            break;
        }
        // add a read event for receive data 
        EventSet(&g_Events[i], nfd, RecvData, &g_Events[i]); 
        EventAdd(g_epollFd, EPOLLIN, &g_Events[i]); 
    }while(0); 
    printf("new conn[%s:%d][time:%d], pos[%d]\n", inet_ntoa(sin.sin_addr),
            ntohs(sin.sin_port), g_Events[i].last_active, i); 
} 
// receive data 
void RecvData(int fd, int events, void *arg) 
{ 
    struct myevent_s *ev = (struct myevent_s*)arg; 
    int len; 
    // receive data
    len = recv(fd, ev->buff+ev->len, sizeof(ev->buff)-1-ev->len, 0);   
    EventDel(g_epollFd, ev);
    if(len > 0)
    {
        ev->len += len;
        ev->buff[len] = '\0'; 
        printf("C[%d]:%s\n", fd, ev->buff); 
        // change to send event 
        EventSet(ev, fd, SendData, ev); 
        EventAdd(g_epollFd, EPOLLOUT, ev); 
    } 
    else if(len == 0) 
    { 
        close(ev->fd); 
        printf("[fd=%d] pos[%d], closed gracefully.\n", fd, ev-g_Events); 
    } 
    else 
    { 
        close(ev->fd); 
        printf("recv[fd=%d] error[%d]:%s\n", fd, errno, strerror(errno)); 
    } 
} 
// send data 
void SendData(int fd, int events, void *arg) 
{ 
    struct myevent_s *ev = (struct myevent_s*)arg; 
    int len; 
    // send data 
    len = send(fd, ev->buff + ev->s_offset, ev->len - ev->s_offset, 0);
    if(len > 0) 
    {
        printf("send[fd=%d], [%d<->%d]%s\n", fd, len, ev->len, ev->buff);
        ev->s_offset += len;
        if(ev->s_offset == ev->len)
        {
            // change to receive event
            EventDel(g_epollFd, ev); 
            EventSet(ev, fd, RecvData, ev); 
            EventAdd(g_epollFd, EPOLLIN, ev); 
        }
    } 
    else 
    { 
        close(ev->fd); 
        EventDel(g_epollFd, ev); 
        printf("send[fd=%d] error[%d]\n", fd, errno); 
    } 
} 
void InitListenSocket(int epollFd, short port) 
{ 
    int listenFd = socket(AF_INET, SOCK_STREAM, 0); 
    fcntl(listenFd, F_SETFL, O_NONBLOCK); // set non-blocking 
    printf("server listen fd=%d\n", listenFd); 
    EventSet(&g_Events[MAX_EVENTS], listenFd, AcceptConn, &g_Events[MAX_EVENTS]); 
    // add listen socket 
    EventAdd(epollFd, EPOLLIN, &g_Events[MAX_EVENTS]); 
    // bind & listen 
    struct sockaddr_in sin; 
    bzero(&sin, sizeof(sin)); 
    sin.sin_family = AF_INET; 
    sin.sin_addr.s_addr = INADDR_ANY; 
    sin.sin_port = htons(port); 
    bind(listenFd, (const struct sockaddr*)&sin, sizeof(sin)); 
    listen(listenFd, 5); 
} 
int main(int argc, char **argv) 
{ 
    unsigned short port = 12345; // default port 
 int i = 0;
 int fds;
 long now;
 int checkPos = 0;
    if(argc == 2){ 
        port = atoi(argv[1]); 
    } 
    // create epoll 
    g_epollFd = epoll_create(MAX_EVENTS); 
    if(g_epollFd <= 0) printf("create epoll failed.%d\n", g_epollFd); 
    // create & bind listen socket, and add to epoll, set non-blocking 
    InitListenSocket(g_epollFd, port); 
    // event loop 
    struct epoll_event events[MAX_EVENTS]; 
    printf("server running:port[%d]\n", port); 
    
    while(1){ 
        // a simple timeout check here, every time 100, better to use a mini-heap, and add timer event 
        now = time(NULL); 
        for(i = 0; i < 100; i++, checkPos++) // doesn't check listen fd 
        { 
            if(checkPos == MAX_EVENTS) checkPos = 0; // recycle 
            if(g_Events[checkPos].status != 1) continue; 
            long duration = now - g_Events[checkPos].last_active; 
            if(duration >= 60) // 60s timeout 
            { 
                close(g_Events[checkPos].fd); 
                printf("[fd=%d] timeout[%d--%d].\n", g_Events[checkPos].fd, g_Events[checkPos].last_active, now); 
                EventDel(g_epollFd, &g_Events[checkPos]); 
            } 
        } 
        // wait for events to happen 
        fds = epoll_wait(g_epollFd, events, MAX_EVENTS, 1000); 
        if(fds < 0){ 
            printf("epoll_wait error, exit\n"); 
            break; 
        } 
        for(i = 0; i < fds; i++){ 
            struct myevent_s *ev = (struct myevent_s*)events[i].data.ptr; 
            if((events[i].events&EPOLLIN)&&(ev->events&EPOLLIN)) // read event 
            { 
                ev->call_back(ev->fd, events[i].events, ev->arg); 
            } 
            if((events[i].events&EPOLLOUT)&&(ev->events&EPOLLOUT)) // write event 
            { 
                ev->call_back(ev->fd, events[i].events, ev->arg); 
            } 
        } 
    } 
    // free resource 
    return 0; 
}  

#ifdef __cplusplus
#if __cplusplus
}
#endif
#endif /* __cplusplus */