fix calculation of daily reconnect time at DST change

Author: ensc

src/time.c

@@ -55,28 +55,25 @@ dhcp_time_t time_get_margin(dhcp_time_t a, dhcp_time_t b,
 }
 
 static time_t get_hhmm(struct tm const *base_tm, unsigned int hhmm,
-		       time_t offset)
+		       unsigned int offset_days)
 {
 	struct tm	tm = {
 		.tm_mday	= base_tm->tm_mday,
 		.tm_mon		= base_tm->tm_mon,
 		.tm_year	= base_tm->tm_year,
-		.tm_hour	= offset == 0 ? hhmm / 100 : 0,
-		.tm_min		= offset == 0 ? hhmm % 100 : 0,
+		.tm_hour	= hhmm / 100,
+		.tm_min		= hhmm % 100,
 		.tm_isdst	= -1,
 	};
 
 	time_t		t;
 
 	t = mktime(&tm);
-	if (offset == 0)
+	if (offset_days == 0)
 		return t;
 
-	t += offset;
-	localtime_r(&t, &tm);
-
-	tm.tm_hour = hhmm / 100;
-	tm.tm_min  = hhmm % 100;
+	tm.tm_mday += offset_days;
+	tm.tm_isdst = -1;
 
 	return mktime(&tm);
 }
@@ -98,7 +95,7 @@ uint32_t time_max_lt(time_t now, int daily_renew)
 
 	renew_tm = get_hhmm(&tm, daily_renew, 0);
 	if (renew_tm < now)
-	    renew_tm = get_hhmm(&tm, daily_renew, 24 * 3600);
+	    renew_tm = get_hhmm(&tm, daily_renew, 1);
 
 	if (renew_tm < now) {
 	    pr_warn("failed to find renew time");