Correct denominators when converting NTP fixed point values to double

and vice-versa; ok tb@

diff --git a/usr.sbin/ntpd/ntp.h b/usr.sbin/ntpd/ntp.h
index fd35bf9..20d67f3 100644 (file)
--- a/usr.sbin/ntpd/ntp.h
+++ b/usr.sbin/ntpd/ntp.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ntp.h,v 1.14 2020/01/30 15:55:41 otto Exp $ */
+/*     $OpenBSD: ntp.h,v 1.15 2023/11/15 15:52:09 otto Exp $ */
 
 /*
  * Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
@@ -43,11 +43,13 @@ struct l_fixedpt {
        u_int32_t int_partl;
        u_int32_t fractionl;
 };
+#define L_DENOMINATOR  (UINT32_MAX + 1ULL)
 
 struct s_fixedpt {
        u_int16_t int_parts;
        u_int16_t fractions;
 };
+#define S_DENOMINATOR  (UINT16_MAX + 1)
 
 /* RFC Section 4
  *

diff --git a/usr.sbin/ntpd/util.c b/usr.sbin/ntpd/util.c
index be113ba..d490601 100644 (file)
--- a/usr.sbin/ntpd/util.c
+++ b/usr.sbin/ntpd/util.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: util.c,v 1.25 2020/01/30 15:55:41 otto Exp $ */
+/*     $OpenBSD: util.c,v 1.26 2023/11/15 15:52:09 otto Exp $ */
 
 /*
  * Copyright (c) 2004 Alexander Guy <alexander.guy@andern.org>
@@ -96,7 +96,7 @@ lfp_to_d(struct l_fixedpt lfp)
        if (lfp.int_partl <= INT32_MAX)
                base++; 
        ret = base * SECS_IN_ERA;
-       ret += (double)(lfp.int_partl) + ((double)lfp.fractionl / UINT_MAX);
+       ret += (double)(lfp.int_partl) + ((double)lfp.fractionl / L_DENOMINATOR);
 
        return (ret);
 }
@@ -109,7 +109,7 @@ d_to_lfp(double d)
        while (d > SECS_IN_ERA)
                d -= SECS_IN_ERA;
        lfp.int_partl = htonl((u_int32_t)d);
-       lfp.fractionl = htonl((u_int32_t)((d - (u_int32_t)d) * UINT_MAX));
+       lfp.fractionl = htonl((u_int32_t)((d - (u_int32_t)d) * L_DENOMINATOR));
 
        return (lfp);
 }
@@ -122,7 +122,7 @@ sfp_to_d(struct s_fixedpt sfp)
        sfp.int_parts = ntohs(sfp.int_parts);
        sfp.fractions = ntohs(sfp.fractions);
 
-       ret = (double)(sfp.int_parts) + ((double)sfp.fractions / USHRT_MAX);
+       ret = (double)(sfp.int_parts) + ((double)sfp.fractions / S_DENOMINATOR);
 
        return (ret);
 }
@@ -133,7 +133,7 @@ d_to_sfp(double d)
        struct s_fixedpt        sfp;
 
        sfp.int_parts = htons((u_int16_t)d);
-       sfp.fractions = htons((u_int16_t)((d - (u_int16_t)d) * USHRT_MAX));
+       sfp.fractions = htons((u_int16_t)((d - (u_int16_t)d) * S_DENOMINATOR));
 
        return (sfp);
 }