From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Tue, 19 Jul 2016 12:46:17 +0000 (+0200)
Subject: util: round up when converting to 32-bit NTP values
X-Git-Tag: 3.0-pre1~159
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7ffe59a7344b480319052de667176bf25fb052ba;p=thirdparty%2Fchrony.git

util: round up when converting to 32-bit NTP values

NTP clients shouldn't get root delay and dispersion smaller than the
server's values.
---

diff --git a/util.c b/util.c
index 9085ff6b..895fbe02 100644
--- a/util.c
+++ b/util.c
@@ -632,11 +632,22 @@ UTI_Int32ToDouble(NTP_int32 x)
 NTP_int32
 UTI_DoubleToInt32(double x)
 {
-  if (x > MAX_NTP_INT32)
-    x = MAX_NTP_INT32;
-  else if (x < 0)
-    x = 0.0;
-  return htonl((NTP_int32)(0.5 + 65536.0 * x));
+  NTP_int32 r;
+
+  if (x >= MAX_NTP_INT32) {
+    r = 0xffffffff;
+  } else if (x <= 0.0) {
+    r = 0;
+  } else {
+    x *= 65536.0;
+    r = x;
+
+    /* Round up */
+    if (r < x)
+      r++;
+  }
+
+  return htonl(r);
 }
 
 /* ================================================== */