From: Guus Sliepen <guus@meshlink.io>
Date: Sun, 5 Apr 2020 23:41:14 +0000 (+0200)
Subject: Fix RTT measurement.
X-Git-Url: http://git.meshlink.io/?p=utcp;a=commitdiff_plain;h=9470c449236afef22210803b359fe44d74e32636;hp=a7d31e61566f0d2e6cb0821fcdaf74ccfc1f8f64

Fix RTT measurement.

Commit 723d8c8b2d96834135f00c0ac4147282e1f0cc2c introduced a bug where we
fail to subtract two timespecs correctly, resulting in incorrect RTT values.
---

diff --git a/utcp.c b/utcp.c
index 383e27f..10d026e 100644
--- a/utcp.c
+++ b/utcp.c
@@ -61,8 +61,7 @@ static void timespec_sub(const struct timespec *a, const struct timespec *b, str
 }
 
 static int32_t timespec_diff_usec(const struct timespec *a, const struct timespec *b) {
-	int64_t diff = (a->tv_sec - b->tv_sec) * 1000000000 + a->tv_sec - b->tv_sec;
-	return diff / 1000;
+	return (a->tv_sec - b->tv_sec) * 1000000 + (a->tv_nsec - b->tv_nsec) / 1000;
 }
 
 static bool timespec_lt(const struct timespec *a, const struct timespec *b) {