Added function for fetching zone serial.

src/libknot/zone/zone-contents.c

@@ -2785,3 +2785,11 @@ const knot_dname_t *knot_zone_contents_find_dname_in_rdata(
 	}
 }
 
+unsigned knot_zone_serial(const knot_zone_contents_t *zone)
+{
+	if (!zone) return 0;
+	const knot_rrset_t *soa = NULL;
+	soa = knot_node_rrset(knot_zone_contents_apex(zone), KNOT_RRTYPE_SOA);
+	return knot_rrset_rdata_soa_serial(soa);
+}
+

src/libknot/zone/zone-contents.h

@@ -505,6 +505,17 @@ int knot_zone_contents_nsec3_name(const knot_zone_contents_t *zone,
 
 void knot_zone_contents_insert_dname_into_table(knot_dname_t **in_dname,
                                                 hattrie_t *lookup_tree);
+
+
+/*!
+ * \brief Fetch zone serial.
+ * 
+ * \param zone Zone.
+ * 
+ * \return serial or 0
+ */
+unsigned knot_zone_serial(const knot_zone_contents_t *zone);
+
 #endif
 
 /*! @} */