From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Fri, 20 Jan 2017 12:17:45 +0000 (+0100)
Subject: ntp: fix time smoothing in interleaved mode
X-Git-Tag: 3.1-pre1~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=da2d33e9a84baa7325503440099dd8f1e567cdd4;p=thirdparty%2Fchrony.git

ntp: fix time smoothing in interleaved mode

When the server's transmit timestamp was updated with a kernel/HW
timestamp, it didn't include the time smoothing offset. If the offset
was larger than one second, the update failed and clients using the
interleaved mode received less accurate timestamps. If the update
succeeded, the clients received timestamps that were not adjusted for
the time smoothing offset, which added an error of up to 0.5s/1s to
their measured offset/delay.

Fix the update to include the smoothing offset in the new timestamp.
---

diff --git a/ntp_core.c b/ntp_core.c
index 48ae3d1a..014f999d 100644
--- a/ntp_core.c
+++ b/ntp_core.c
@@ -2036,6 +2036,9 @@ NCR_ProcessTxUnknown(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_a
   if (log_index < 0)
     return;
 
+  if (SMT_IsEnabled() && NTP_LVM_TO_MODE(message->lvm) == MODE_SERVER)
+    UTI_AddDoubleToTimespec(&tx_ts->ts, SMT_GetOffset(&tx_ts->ts), &tx_ts->ts);
+
   CLG_GetNtpTimestamps(log_index, &local_ntp_rx, &local_ntp_tx);
 
   UTI_Ntp64ToTimespec(local_ntp_tx, &local_tx.ts);