/* Connect to loopback address port 65535, send a datagram, and expect an ICMP connection refused packet, get error with SO_ERROR, and then test the poll bits. */ #include "udp.h" int main(void) { int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if ( fd < 0 ) err(1, "socket"); struct sockaddr_in sin; memset(&sin, 0, sizeof(sin)); sin.sin_family = AF_INET; sin.sin_addr.s_addr = htobe32(INADDR_LOOPBACK); sin.sin_port = htobe16(65535); if ( connect(fd, (const struct sockaddr*) &sin, sizeof(sin)) < 0 ) err(1, "connect"); char x = 'x'; if ( send(fd, &x, sizeof(x), 0) < 0 ) warn("send"); usleep(50000); struct pollfd pfd; memset(&pfd, 0, sizeof(pfd)); pfd.fd = fd; pfd.events = POLLIN | POLLOUT; int num_events = poll(&pfd, 1, 0); if ( num_events < 0 ) err(1, "first poll"); if ( num_events == 0 ) errx(1, "first poll returned 0"); printf("first poll: 0"); if ( pfd.revents & POLLIN ) printf(" | POLLIN"); if ( pfd.revents & POLLPRI ) printf(" | POLLPRI"); if ( pfd.revents & POLLOUT ) printf(" | POLLOUT"); #if defined(POLLRDHUP) && POLLRDHUP != POLLHUP if ( pfd.revents & POLLRDHUP ) printf(" | POLLRDHUP"); #endif if ( pfd.revents & POLLERR ) printf(" | POLLERR"); if ( pfd.revents & POLLHUP ) printf(" | POLLHUP"); #if POLLRDNORM != POLLIN if ( pfd.revents & POLLRDNORM ) printf(" | POLLRDNORM"); #endif #if POLLRDBAND != POLLPRI if ( pfd.revents & POLLRDBAND ) printf(" | POLLRDBAND"); #endif #if POLLWRNORM != POLLOUT if ( pfd.revents & POLLWRNORM ) printf(" | POLLWRNORM"); #endif #if POLLWRBAND != POLLOUT if ( pfd.revents & POLLWRBAND ) printf(" | POLLWRBAND"); #endif putchar('\n'); fflush(stdout); int errnum; socklen_t errnumlen = sizeof(errnum); if ( getsockopt(fd, SOL_SOCKET, SO_ERROR, &errnum, &errnumlen) < 0 ) err(1, "getsockopt: SO_ERROR"); errno = errnum; if ( errnum ) warn("SO_ERROR"); else warnx("SO_ERROR: no error"); memset(&pfd, 0, sizeof(pfd)); pfd.fd = fd; pfd.events = POLLIN | POLLOUT; num_events = poll(&pfd, 1, 0); if ( num_events < 0 ) err(1, "second poll"); if ( num_events == 0 ) errx(1, "second poll returned 0"); printf("second poll: 0"); if ( pfd.revents & POLLIN ) printf(" | POLLIN"); if ( pfd.revents & POLLPRI ) printf(" | POLLPRI"); if ( pfd.revents & POLLOUT ) printf(" | POLLOUT"); #if defined(POLLRDHUP) && POLLRDHUP != POLLHUP if ( pfd.revents & POLLRDHUP ) printf(" | POLLRDHUP"); #endif if ( pfd.revents & POLLERR ) printf(" | POLLERR"); if ( pfd.revents & POLLHUP ) printf(" | POLLHUP"); #if POLLRDNORM != POLLIN if ( pfd.revents & POLLRDNORM ) printf(" | POLLRDNORM"); #endif #if POLLRDBAND != POLLPRI if ( pfd.revents & POLLRDBAND ) printf(" | POLLRDBAND"); #endif #if POLLWRNORM != POLLOUT if ( pfd.revents & POLLWRNORM ) printf(" | POLLWRNORM"); #endif #if POLLWRBAND != POLLOUT if ( pfd.revents & POLLWRBAND ) printf(" | POLLWRBAND"); #endif putchar('\n'); return 0; }