/* Maximum acceptable root distance in seconds. */
#define NTP_MAX_ROOT_DISTANCE 5.0
+/* Maximum number of missed replies before selecting another source. */
+#define NTP_MAX_MISSED_REPLIES 2
+
/*
* "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
* in seconds relative to 0h on 1 January 1900."
return manager_connect(m);
}
- r = sd_event_add_time(
- m->event,
- &m->event_timeout,
- clock_boottime_or_monotonic(),
- now(clock_boottime_or_monotonic()) + TIMEOUT_USEC, 0,
- manager_timeout, m);
+ /* re-arm timer with increasing timeout, in case the packets never arrive back */
+ if (m->retry_interval > 0) {
+ if (m->retry_interval < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
+ m->retry_interval *= 2;
+ } else
+ m->retry_interval = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
+
+ r = manager_arm_timer(m, m->retry_interval);
if (r < 0) {
- log_error("Failed to arm timeout timer: %s", strerror(-r));
+ log_error("Failed to rearm timer: %s", strerror(-r));
return r;
}
+ m->missed_replies++;
+ if (m->missed_replies > NTP_MAX_MISSED_REPLIES) {
+ r = sd_event_add_time(
+ m->event,
+ &m->event_timeout,
+ clock_boottime_or_monotonic(),
+ now(clock_boottime_or_monotonic()) + TIMEOUT_USEC, 0,
+ manager_timeout, m);
+ if (r < 0) {
+ log_error("Failed to arm timeout timer: %s", strerror(-r));
+ return r;
+ }
+ }
+
return 0;
}
return 0;
}
+ m->missed_replies = 0;
+
/* check our "time cookie" (we just stored nanoseconds in the fraction field) */
if (be32toh(ntpmsg.origin_time.sec) != m->trans_time.tv_sec + OFFSET_1900_1970 ||
be32toh(ntpmsg.origin_time.frac) != m->trans_time.tv_nsec) {
/* valid packet */
m->pending = false;
+ m->retry_interval = 0;
/* announce leap seconds */
if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
if (r < 0)
return -errno;
- setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
+ r = setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
+ if (r < 0)
+ return -errno;
return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
}
assert_return(m->current_server_name, -EHOSTUNREACH);
assert_return(m->current_server_address, -EHOSTUNREACH);
- m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
+ m->missed_replies = NTP_MAX_MISSED_REPLIES;
+ if (m->poll_interval_usec == 0)
+ m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
server_address_pretty(m->current_server_address, &pretty);
log_info("Using NTP server %s (%s).", strna(pretty), m->current_server_name->string);