diff --git a/src/timesync/timesyncd-manager.c b/src/timesync/timesyncd-manager.c index 19a28f37e29..a66852d7d28 100644 --- a/src/timesync/timesyncd-manager.c +++ b/src/timesync/timesyncd-manager.c @@ -92,6 +92,9 @@ /* 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." @@ -206,15 +209,18 @@ static int manager_send_request(Manager *m) { 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); - if (r < 0) { - log_error("Failed to arm timeout 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; @@ -549,6 +555,8 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re 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) { @@ -712,6 +720,7 @@ static int manager_begin(Manager *m) { assert_return(m->current_server_name, -EHOSTUNREACH); assert_return(m->current_server_address, -EHOSTUNREACH); + m->missed_replies = NTP_MAX_MISSED_REPLIES; m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC; server_address_pretty(m->current_server_address, &pretty); diff --git a/src/timesync/timesyncd-manager.h b/src/timesync/timesyncd-manager.h index 0ac0e179c17..8296d41295f 100644 --- a/src/timesync/timesyncd-manager.h +++ b/src/timesync/timesyncd-manager.h @@ -53,6 +53,7 @@ struct Manager { ServerName *current_server_name; ServerAddress *current_server_address; int server_socket; + int missed_replies; uint64_t packet_count; sd_event_source *event_timeout;