static int tcp_wait_for_events(tcp_context_t *tcp)
{
/* Wait for events. */
fdset_t *set = &tcp->set;
int nfds = poll(set->pfd, set->n, TCP_SWEEP_INTERVAL * 1000);
/* Mark the time of last poll call. */
time_now(&tcp->last_poll_time);
bool is_throttled = (tcp->last_poll_time.tv_sec < tcp->throttle_end.tv_sec);
if (!is_throttled) {
/* Configuration limit, infer maximal pool size. */
rcu_read_lock();
conf_val_t *val = &conf()->cache.srv_max_tcp_clients;
unsigned max_per_set = MAX(conf_int(val) / conf_tcp_threads(conf()), 1);
rcu_read_unlock();
/* Subtract master sockets check limits. */
is_throttled = (set->n - tcp->client_threshold) >= max_per_set;
}
/* Process events. */
unsigned i = 0;
while (nfds > 0 && i < set->n) {
bool should_close = false;
int fd = set->pfd[i].fd;
if (set->pfd[i].revents & (POLLERR|POLLHUP|POLLNVAL)) {
should_close = (i >= tcp->client_threshold);
--nfds;
} else if (set->pfd[i].revents & (POLLIN)) {
/* Master sockets */
if (i < tcp->client_threshold) {
if (!is_throttled && tcp_event_accept(tcp, i) == KNOT_EBUSY) {
time_now(&tcp->throttle_end);
tcp->throttle_end.tv_sec += tcp_throttle();
}
/* Client sockets */
} else {
if (tcp_event_serve(tcp, i) != KNOT_EOK) {
should_close = true;
}
}
--nfds;
}
/* Evaluate */
if (should_close) {
fdset_remove(set, i);
close(fd);
} else {
++i;
}
}
return nfds;
}
int tcp_accept(int fd)
{
/* Accept incoming connection. */
int incoming = accept(fd, 0, 0);
/* Evaluate connection. */
if (incoming < 0) {
int en = errno;
if (en != EINTR && en != EAGAIN) {
log_error("cannot accept connection (%d)", errno);
if (en == EMFILE || en == ENFILE ||
en == ENOBUFS || en == ENOMEM) {
int throttle = tcp_throttle();
log_error("throttling TCP connection pool for "
"%d seconds, too many allocated "
"resources", throttle);
sleep(throttle);
}
}
} else {
dbg_net("tcp: accepted connection fd=%d\n", incoming);
/* Set recv() timeout. */
#ifdef SO_RCVTIMEO
struct timeval tv;
rcu_read_lock();
tv.tv_sec = conf()->max_conn_idle;
rcu_read_unlock();
tv.tv_usec = 0;
if (setsockopt(incoming, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0) {
log_warning("cannot set up TCP connection watchdog "
"timer, fd %d", incoming);
}
#endif
}
return incoming;
}
