From: Roy Marples <roy@marples.name>
Date: Fri, 18 Nov 2016 15:26:45 +0000 (+0000)
Subject: Improve NTP timestamp from realtime and fix the double host to network translation... 
X-Git-Tag: v6.11.6~11
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c1dad506f80cef01fa67a0a0c37313df098a4961;p=thirdparty%2Fdhcpcd.git

Improve NTP timestamp from realtime and fix the double host to network translation on it.
---

diff --git a/auth.c b/auth.c
index 48bf04ab..45fe9aa5 100644
--- a/auth.c
+++ b/auth.c
@@ -433,22 +433,21 @@ get_next_rdm_monotonic_counter(struct auth *auth)
 	return rdm;
 }
 
-#define JAN_1970       2208988800U    /* 1970 - 1900 in seconds */
+#define	NTP_EPOCH	2208988800U	/* 1970 - 1900 in seconds */
+#define	NTP_SCALE_FRAC	4294967295.0	/* max value of the fractional part */
 static uint64_t
 get_next_rdm_monotonic_clock(struct auth *auth)
 {
 	struct timespec ts;
-	uint32_t pack[2];
+	uint64_t secs, rdm;
 	double frac;
-	uint64_t rdm;
 
 	if (clock_gettime(CLOCK_REALTIME, &ts) != 0)
 		return ++auth->last_replay; /* report error? */
-	pack[0] = htonl((uint32_t)ts.tv_sec + JAN_1970);
-	frac = ((double)ts.tv_nsec / 1e9 * 0x100000000ULL);
-	pack[1] = htonl((uint32_t)frac);
 
-	memcpy(&rdm, &pack, sizeof(rdm));
+	secs = (uint64_t)ts.tv_sec + NTP_EPOCH;
+	frac = ((double)ts.tv_nsec / 1e9 * NTP_SCALE_FRAC);
+	rdm = (secs << 32) | (uint64_t)frac;
 	return rdm;
 }