3130. [func] Support alternate methods for managing a dynamic

zone's serial number.  Two methods are currently
                        defined using serial-update-method, "increment"
                        (default) and "unixtime".  [RT #23849]

lib/dns/update.c

@@ -0,0 +1,28 @@
+/*
+ * Copyright
+ */
+
+#include "config.h"
+
+#include <isc/stdtime.h>
+#include <isc/serial.h>
+
+#include <dns/update.h>
+
+isc_uint32_t
+dns_update_soaserial(isc_uint32_t serial, dns_updatemethod_t method) {
+	isc_stdtime_t now;
+
+        if (method == dns_updatemethod_unixtime) {
+		isc_stdtime_get(&now);
+	        if (now != 0 && isc_serial_gt(now, serial))
+                	return (now);
+	}
+
+	/* RFC1982 */
+	serial = (serial + 1) & 0xFFFFFFFF;
+	if (serial == 0)
+		serial = 1;
+
+	return (serial);
+}