Clamp every elapsed time span at zero, using a set of helper functions

1 files changed, 2 insertions, 2 deletions

diff --git a/src/ot_udp.c b/src/ot_udp.c
index 644b71d..e67ca1f 100644
--- a/src/ot_udp.c
+++ b/src/ot_udp.c
@@ -39,12 +39,12 @@ static void udp_make_connectionid(uint32_t connid[2], const ot_ip6 remoteip, int
   int      i;
   uint32_t current_key_of_the_hour;
 
-  if (time_now_minutes() - g_hour_of_the_key >= 60) {
+  if (time_since_minutes(g_hour_of_the_key) >= 60) {
     uint32_t old_key_of_the_hour = g_key_of_the_hour[0];
     uint32_t new_key_of_the_hour = random_uint32();
     /* If in the meantime another thread has performed
        key rotation, do not overwrite their results */
-    if (time_now_minutes() - g_hour_of_the_key >= 60) {
+    if (time_since_minutes(g_hour_of_the_key) >= 60) {
       /* Upgrade en bloc */
       g_hour_of_the_key    = time_now_minutes();
       g_key_of_the_hour[0] = new_key_of_the_hour;