Support an allow list for the 'classified' plugin

plugins/classified/classified.go

@@ -17,6 +17,7 @@ import (
 type classifiedPlugin struct {
 	counters *DecayCounterMap
 	limit    uint64
+	allow    util.StringSet
 }
 
 func newClassifiedPlugin() *classifiedPlugin {
@@ -38,6 +39,14 @@ func (p *classifiedPlugin) Init(config map[string]interface{}, db *bolt.DB) erro
 		p.limit = uint64(i)
 	}
 
+	if f, ok := config["classified_allow_list"].(string); ok && f != "" {
+		wl, err := util.ReadStringSetFromFile(f)
+		if err != nil {
+			return err
+		}
+		p.allow = wl
+	}
+
 	return nil
 }
 
@@ -48,6 +57,11 @@ func (p *classifiedPlugin) Test(ctx context.Context, comment *nospam.Comment) (f
 	}
 
 	for domain := range tlds {
+		if p.allow != nil {
+			if _, ok := p.allow.HasPrefix(domain); ok {
+				continue
+			}
+		}
 		value, err := p.counters.Get(domain)
 		if err != nil {
 			continue