84 lines
2.2 KiB
C
84 lines
2.2 KiB
C
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <errno.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include <netdb.h>
|
||
|
|
#include <fcntl.h>
|
||
|
|
#include <sys/types.h>
|
||
|
|
#include <netinet/in.h>
|
||
|
|
#include <sys/socket.h>
|
||
|
|
#include <netinet/tcp.h>
|
||
|
|
#include <sys/epoll.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
#define MAXEVENTS 1
|
||
|
|
|
||
|
|
int guard(int n, char * err) { if (n == -1) { perror(err); exit(1); } return n; }
|
||
|
|
|
||
|
|
int main(int argc, char *argv[])
|
||
|
|
{
|
||
|
|
int sfd, sockErr, numbytes;
|
||
|
|
int port = 53;
|
||
|
|
char address[] = "8.8.8.8";
|
||
|
|
|
||
|
|
struct hostent *he;
|
||
|
|
struct sockaddr_in their_addr;
|
||
|
|
struct epoll_event event;
|
||
|
|
struct epoll_event *events;
|
||
|
|
|
||
|
|
printf("PINGING: %s:%d\n", address, port);
|
||
|
|
|
||
|
|
if ((he=gethostbyname(address)) == NULL) {
|
||
|
|
herror("gethostbyname");
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
|
||
|
|
if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
|
||
|
|
perror("socket");
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
|
||
|
|
int i = 1;
|
||
|
|
guard(setsockopt(sfd, IPPROTO_TCP, TCP_QUICKACK, (void *)&i, sizeof(i)), "setsockopt");
|
||
|
|
guard(fcntl(sfd, F_SETFL, O_NONBLOCK), "fcntl: failed to set non-blocking");
|
||
|
|
|
||
|
|
their_addr.sin_family = AF_INET; /* host byte order */
|
||
|
|
their_addr.sin_port = htons(port); /* short, network byte order */
|
||
|
|
their_addr.sin_addr = *((struct in_addr *)he->h_addr);
|
||
|
|
bzero(&(their_addr.sin_zero), 8); /* zero the rest of the struct */
|
||
|
|
|
||
|
|
connect(sfd, (struct sockaddr *)&their_addr, sizeof(struct sockaddr));
|
||
|
|
|
||
|
|
int epfd = guard(epoll_create1(EPOLL_CLOEXEC), "epoll_create");
|
||
|
|
|
||
|
|
event.data.fd = sfd;
|
||
|
|
event.events = EPOLLOUT | EPOLLIN | EPOLLET;
|
||
|
|
guard(epoll_ctl (epfd, EPOLL_CTL_ADD, sfd, &event), "epoll_ctl");
|
||
|
|
|
||
|
|
/* Buffer where events are returned */
|
||
|
|
events = calloc(MAXEVENTS, sizeof event);
|
||
|
|
|
||
|
|
int nEvents = epoll_wait(epfd, events, MAXEVENTS, -1);
|
||
|
|
if (nEvents == 0) {
|
||
|
|
perror("epoll_wait");
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
|
||
|
|
printf("epoll event flags: %d\n", events[0].events);
|
||
|
|
printf("epoll event fd: %d\n", events[0].data.fd);
|
||
|
|
|
||
|
|
int iSocketOption = 0;
|
||
|
|
int iSocketOptionLen = sizeof(int);
|
||
|
|
sockErr = getsockopt(sfd, SOL_SOCKET, SO_ERROR, (char *)&iSocketOption, &iSocketOptionLen);
|
||
|
|
if (sockErr != 0) {
|
||
|
|
perror("getsockopt");
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
|
||
|
|
close(sfd);
|
||
|
|
|
||
|
|
printf("SUCCESS\n");
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|