lib/dns: add method to populate internal caches by Zone

The InternalPopulateZone populate the internal caches from Zone's
messages.

lib/dns/caches.go

@@ -37,6 +37,9 @@ type Caches struct {
 	// by is domain name.
 	external map[string]*answers
 
+	// zone contains internal zones, with its origin as the key.
+	zone map[string]*Zone
+
 	// lru contains list of external answers, ordered by access time in
 	// ascending order (the least recently used, LRU, record will be on
 	// the top).
@@ -79,6 +82,7 @@ func (c *Caches) init(pruneDelay, pruneThreshold time.Duration, debug int) {
 
 	c.internal = make(map[string]*answers)
 	c.external = make(map[string]*answers)
+	c.zone = make(map[string]*Zone)
 	c.lru = list.New()
 	c.debug = debug
 
@@ -308,6 +312,18 @@ func (c *Caches) InternalPopulateRecords(listRR []*ResourceRecord, from string)
 	return nil
 }
 
+// InternalPopulateZone populate the internal caches from Zone.
+func (c *Caches) InternalPopulateZone(zone *Zone) {
+	if zone == nil {
+		return
+	}
+	if len(zone.Origin) == 0 {
+		return
+	}
+	c.zone[zone.Origin] = zone
+	c.InternalPopulate(zone.Messages(), zone.Path)
+}
+
 // InternalRemoveNames remove internal caches by domain names.
 func (c *Caches) InternalRemoveNames(names []string) {
 	var (

lib/dns/zone.go

@@ -48,7 +48,7 @@ func NewZone(file, origin string) (zone *Zone) {
 
 // LoadZoneDir load DNS record from zone formatted files in
 // directory "dir".
-// On success, it will return map of zone Origin and its content as list
+// On success, it will return map of file name and Zone content as list
 // of Message.
 // On fail, it will return possible partially parse zone file and an error.
 func LoadZoneDir(dir string) (zoneFiles map[string]*Zone, err error) {
@@ -99,7 +99,7 @@ func LoadZoneDir(dir string) (zoneFiles map[string]*Zone, err error) {
 			return zoneFiles, fmt.Errorf("LoadZoneDir %q: %w", dir, err)
 		}
 
-		zoneFiles[zone.Origin] = zone
+		zoneFiles[name] = zone
 	}
 
 	err = d.Close()