85 lines
3.5 KiB
Diff
85 lines
3.5 KiB
Diff
From e8206972be6a7ebeb198cd0d400bc7a94a6a5fc5 Mon Sep 17 00:00:00 2001
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From: Miroslav Lichvar <mlichvar@redhat.com>
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Date: Tue, 2 Sep 2014 14:29:51 +0200
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Subject: [PATCH] timesyncd: allow two missed replies before reselecting server
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After receiving a reply from the server, allow two missed replies before
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switching to another server to avoid unnecessary clock hopping when
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packets are getting lost in the network.
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---
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src/timesync/timesyncd-manager.c | 27 ++++++++++++++++++---------
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src/timesync/timesyncd-manager.h | 1 +
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2 files changed, 19 insertions(+), 9 deletions(-)
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diff --git a/src/timesync/timesyncd-manager.c b/src/timesync/timesyncd-manager.c
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index 19a28f37e2..a66852d7d2 100644
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--- a/src/timesync/timesyncd-manager.c
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+++ b/src/timesync/timesyncd-manager.c
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@@ -92,6 +92,9 @@
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/* Maximum acceptable root distance in seconds. */
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#define NTP_MAX_ROOT_DISTANCE 5.0
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+/* Maximum number of missed replies before selecting another source. */
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+#define NTP_MAX_MISSED_REPLIES 2
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+
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/*
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* "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
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* in seconds relative to 0h on 1 January 1900."
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@@ -206,15 +209,18 @@ static int manager_send_request(Manager *m) {
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return manager_connect(m);
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}
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- r = sd_event_add_time(
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- m->event,
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- &m->event_timeout,
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- clock_boottime_or_monotonic(),
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- now(clock_boottime_or_monotonic()) + TIMEOUT_USEC, 0,
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- manager_timeout, m);
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- if (r < 0) {
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- log_error("Failed to arm timeout timer: %s", strerror(-r));
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- return r;
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+ m->missed_replies++;
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+ if (m->missed_replies > NTP_MAX_MISSED_REPLIES) {
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+ r = sd_event_add_time(
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+ m->event,
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+ &m->event_timeout,
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+ clock_boottime_or_monotonic(),
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+ now(clock_boottime_or_monotonic()) + TIMEOUT_USEC, 0,
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+ manager_timeout, m);
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+ if (r < 0) {
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+ log_error("Failed to arm timeout timer: %s", strerror(-r));
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+ return r;
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+ }
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}
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return 0;
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@@ -549,6 +555,8 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
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return 0;
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}
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+ m->missed_replies = 0;
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+
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/* check our "time cookie" (we just stored nanoseconds in the fraction field) */
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if (be32toh(ntpmsg.origin_time.sec) != m->trans_time.tv_sec + OFFSET_1900_1970 ||
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be32toh(ntpmsg.origin_time.frac) != m->trans_time.tv_nsec) {
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@@ -712,6 +720,7 @@ static int manager_begin(Manager *m) {
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assert_return(m->current_server_name, -EHOSTUNREACH);
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assert_return(m->current_server_address, -EHOSTUNREACH);
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+ m->missed_replies = NTP_MAX_MISSED_REPLIES;
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m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
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server_address_pretty(m->current_server_address, &pretty);
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diff --git a/src/timesync/timesyncd-manager.h b/src/timesync/timesyncd-manager.h
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index 0ac0e179c1..8296d41295 100644
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--- a/src/timesync/timesyncd-manager.h
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+++ b/src/timesync/timesyncd-manager.h
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@@ -53,6 +53,7 @@ struct Manager {
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ServerName *current_server_name;
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ServerAddress *current_server_address;
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int server_socket;
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+ int missed_replies;
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uint64_t packet_count;
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sd_event_source *event_timeout;
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