test.cpp

//
// Created by lixutong on 20-5-18.
//

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

static const char *request = "GET http://localhost/test.html HTTP/1.1\r\nConnection: keep-alive\r\n\r\nxxxxxxxxxxxxxx";

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;
}

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

/* write n bytes data to server */
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 (true) {
        bytes_write = send(sockfd, buffer, len, 0);
        if (bytes_write == -1)
            return false;
        else if (bytes_write == 0)
            return false;
        len -= bytes_write;
        buffer = buffer + bytes_write;
        if (len <= 0)
            return true;
    }
}

/* read data from server */
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)
        return false;
    else if (bytes_read == 0)
        return false;
    printf("read in %d bytes from socket %d with content: %s\n", bytes_read, sockfd, buffer);
    return true;
}

/* request N TCP connection to server*/
void start_conn(int epoll_fd, int num, const char *ip, int port) {
    struct sockaddr_in address;
    bzero(&address, sizeof(address));
    address.sin_family = AF_INET;
    inet_pton(AF_INET, ip, &address.sin_addr);
    address.sin_port = htons(port);

    for (int i = 0; i < num; ++ i) {
        sleep(1);
        int sockfd = socket(PF_INET, SOCK_STREAM, 0);
        printf("create 1 sock\n");
        if (sockfd < 0)
            continue;
        if (connect(sockfd, (struct sockaddr*)&address, sizeof(address)) == 0) {
            printf("build connection %d\n", i);
            addfd(epoll_fd, sockfd);
        }
    }
}

/* close connection */
void close_conn(int epoll_fd, int sockfd) {
    epoll_ctl(epoll_fd, EPOLL_CTL_DEL, sockfd, 0);
    close(sockfd);
}

int main(int argc, char *argv[]) {
    assert(argc == 4);
    int epoll_fd = epoll_create(100);
    start_conn(epoll_fd, atoi(argv[3]), argv[1], atoi(argv[2]));
    epoll_event events[10000];
    char buffer[2048];
    while (true) {
        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);
        }
    }
}