From: Juergen Perlinger <perlinger@ntp.org>
Date: Tue, 29 Mar 2016 16:22:03 +0000 (+0200)
Subject: [Bug 3031] ntp broadcastclient unable to synchronize to an server when the time of... 
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2d516f6fc84942983a51f9adfd9d86632006128f;p=thirdparty%2Fntp.git

[Bug 3031] ntp broadcastclient unable to synchronize to an server when the time of server changed.
 - Check the initial delay calculation and reject/unpeer the broadcast server if the delay exceeds 50ms.
   Retry again after the next broadcast packet.

bk: 56faababWnuOu3Z_P0x0Xl8BJoxaKw
---

diff --git a/ChangeLog b/ChangeLog
index c70fe8fc5..c67a28f5e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,11 @@
 
 * [Bug 2994] Systems with HAVE_SIGNALED_IO fail to compile. perlinger@ntp.org
 * [Bug 2995] Fixes to compile on Windows
+* [Bug 3031] ntp broadcastclient unable to synchronize to an server
+             when the time of server changed. perlinger@ntp.org
+  - Check the initial delay calculation and reject/unpeer the broadcast
+    server if the delay exceeds 50ms. Retry again after the next
+    broadcast packet.
 
 ---
 (4.2.8p6) 2016/01/20 Released by Harlan Stenn <stenn@ntp.org>
diff --git a/ntpd/ntp_proto.c b/ntpd/ntp_proto.c
index ad454099f..43f166f26 100644
--- a/ntpd/ntp_proto.c
+++ b/ntpd/ntp_proto.c
@@ -1958,6 +1958,9 @@ process_packet(
 			peer->aorg = p_xmt;
 			peer->borg = peer->dst;
 			if (t34 < 0 || t34 > 1.) {
+				/* drop all if in the initial volley */
+				if (FLAG_BC_VOL & peer->flags)
+					goto bcc_init_volley_fail;
 				snprintf(statstr, sizeof(statstr),
 				    "offset %.6f delay %.6f", t21, t34);
 				report_event(PEVNT_XERR, peer, statstr);
@@ -1983,10 +1986,18 @@ process_packet(
 		 * between the unicast timestamp and the broadcast
 		 * timestamp. This works for both basic and interleaved
 		 * modes.
+		 * [Bug 3031] Don't keep this peer when the delay 
+		 * calculation gives reason to suspect clock steps.
+		 * This is assumed for delays > 50ms.
 		 */
 		if (FLAG_BC_VOL & peer->flags) {
 			peer->flags &= ~FLAG_BC_VOL;
 			peer->delay = fabs(peer->offset - p_offset) * 2;
+			if (peer->delay > 0.05) {
+	bcc_init_volley_fail:
+				unpeer(peer);
+				return;
+			}
 		}
 		p_del = peer->delay;
 		p_offset += p_del / 2;