epoll实现压测工具

代码：

/*
 * g++ -o stress_test ./stress_test.cpp
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

#include <unistd.h>
#include <sys/types.h>
#include <sys/epoll.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

static const char *request = "GET / HTTP/1.1\r\nHost: 192.168.1.5\r\nConnection: keep-alive\r\n\r\n";

int setnonblocking(int fd)
{
    int old_option = fcntl(fd, F_GETFL);
    int new_option = old_option | O_NONBLOCK;
    fcntl(fd, F_SETFL, new_option);
    
    return old_option;
}

int add_fd(int epoll_fd, int fd)
{
    struct epoll_event event;
    event.events = EPOLLOUT | EPOLLET | EPOLLERR;
    event.data.fd = fd;
    epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &event);
    setnonblocking(fd);
}

bool write_nbytes(int sockfd, const char *buffer, int len)
{
    int bytes_write = 0;
    printf("write out %d bytes to socket %d\n", len, sockfd);
    while(1)
    {
        bytes_write = send(sockfd, buffer, len, 0);
        if (bytes_write == -1)
        {
            printf("send failed, errno[%d], error[%s]\n", errno, strerror(errno));
            return false;
        }
        else if (bytes_write == 0)
        {
            printf("send 0 bytes\n");
            return false;
        }

        len -= bytes_write;
        buffer = buffer + bytes_write;
        if (len <= 0)
        {
            return true;
        }
    }
}

bool read_once(int sockfd, char *buffer, int len)
{
    int bytes_read = 0;
    memset(buffer, '\0', len);
    bytes_read = recv(sockfd, buffer, len, 0);
    if (bytes_read == -1)
    {
        printf("recv failed, errno[%d], error[%s]\n", errno, strerror(errno));
        return false;
    }
    else if (bytes_read == 0)
    {
        printf("recv 0 bytes\n");
        return false;
    }
    printf("read in %d bytes from socket %d\n", bytes_read, sockfd);

    return true;
}

int start_conn(int epoll_fd, const char *ip, int port, int num)
{
    struct sockaddr_in addr;
    bzero(&addr, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = inet_addr(ip);
    addr.sin_port = htons(port);

    socklen_t len = sizeof(addr);
    for (int i = 0; i < num; ++i)
    {
        sleep(1);
        int fd = socket(AF_INET, SOCK_STREAM, 0);
        if (fd == -1)
        {
            printf("socket failed, errno[%d], error[%s]\n", errno, strerror(errno));
            continue;
        }

        if (connect(fd, (struct sockaddr*)&addr, len) == 0)
        {
            printf("build connection %d\n", i);
            add_fd(epoll_fd, fd);
        }
        else
        {
            printf("connect failed, errno[%d], error[%s]\n", errno, strerror(errno));
            continue;
        }
    }
}

int close_conn(int epoll_fd, int fd)
{
    epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fd, NULL);

    printf("close socket[%d]\n", fd);
    close(fd);
}

int main(int argc, char **argv)
{
    if (argc != 4)
    {
        printf("usage:stress_test ip port num\n");
        exit(-1);
    }

    int epoll_fd = epoll_create(10000);
    start_conn(epoll_fd, argv[1], atoi(argv[2]), atoi(argv[3]));
    epoll_event events[10000];
    char buffer[2048];
    while (1)
    {
        int fds = epoll_wait(epoll_fd, events, 10000, 2000);
        for (int i = 0; i < fds; ++i)
        {
            int sockfd = events[i].data.fd;
            if (events[i].events & EPOLLIN)
            {
                if (!read_once(sockfd, buffer, 2048))
                {
                    close_conn(epoll_fd, sockfd);
                }

                struct epoll_event event;
                event.events = EPOLLOUT | EPOLLET | EPOLLERR;
                event.data.fd = sockfd;
                epoll_ctl(epoll_fd, EPOLL_CTL_MOD, sockfd, &event);
            }
            else if (events[i].events & EPOLLOUT)
            {
                if (!write_nbytes(sockfd, request, strlen(request)))
                {
                    close_conn(epoll_fd, sockfd);
                }

                struct epoll_event event;
                event.events = EPOLLIN | EPOLLET | EPOLLERR;
                event.data.fd = sockfd;
                epoll_ctl(epoll_fd, EPOLL_CTL_MOD, sockfd, &event);
            }
            else if (events[i].events & EPOLLERR)
            {
                close_conn(epoll_fd, sockfd);
            }
        }
    }

    return 0;
}