Clean and case-insensitive lookups for qname in pebble database

Clean and case-insensitive qname in JSON struct sent north

Author: zluudg

pkg/protocols/protocols.go

@@ -1,6 +1,7 @@
 package protocols
 
 import (
+	"strings"
 	"time"
 
 	"github.com/miekg/dns"
@@ -101,10 +102,11 @@ func NewQnameEvent(msg *dns.Msg, ts time.Time) NewQnameJSON {
 
 	qType := int(msg.Question[0].Qtype)
 	qClass := int(msg.Question[0].Qclass)
+	qname := strings.ToLower(strings.ToValidUTF8(msg.Question[0].Name, ""))
 
 	return NewQnameJSON{
 		Type:      NewQnameJSONType,
-		Qname:     msg.Question[0].Name,
+		Qname:     qname,
 		Qtype:     &qType,
 		Qclass:    &qClass,
 		Timestamp: &ts,

pkg/runner/runner.go

@@ -1831,19 +1831,21 @@ func (edm *dnstapMinimiser) qnameSeen(msg *dns.Msg, seenQnameLRU *lru.Cache[stri
 	// only move an already added entry to the front of the
 	// eviction list which should be OK.
 
-	_, ok := seenQnameLRU.Get(msg.Question[0].Name)
+	qname := strings.ToLower(strings.ToValidUTF8(msg.Question[0].Name, ""))
+
+	_, ok := seenQnameLRU.Get(qname)
 	if ok {
 		// It exists in the LRU cache
 		return true
 	}
 	// Add it to the LRU
-	evicted := seenQnameLRU.Add(msg.Question[0].Name, struct{}{})
+	evicted := seenQnameLRU.Add(qname, struct{}{})
 	if evicted {
 		edm.promSeenQnameLRUEvicted.Inc()
 	}
 
 	// It was not in the LRU cache, does it exist in pebble (on disk)?
-	_, closer, err := pdb.Get([]byte(msg.Question[0].Name))
+	_, closer, err := pdb.Get([]byte(qname))
 	if err == nil {
 		// The value exists in pebble
 		if err := closer.Close(); err != nil {
@@ -1854,7 +1856,7 @@ func (edm *dnstapMinimiser) qnameSeen(msg *dns.Msg, seenQnameLRU *lru.Cache[stri
 
 	// If the key does not exist in pebble we insert it
 	if errors.Is(err, pebble.ErrNotFound) {
-		if err := pdb.Set([]byte(msg.Question[0].Name), []byte{}, pebble.Sync); err != nil {
+		if err := pdb.Set([]byte(qname), []byte{}, pebble.Sync); err != nil {
 			edm.log.Error("unable to insert key in pebble", "error", err)
 		}
 		return false