plugin/dns64: preserve A fallback response codes (#8619)

* plugin/dns64: preserve fallback response codes Signed-off-by: xinjun.jiang <xinjun.jiang@daocloud.io> * plugin/dns64: mark written fallback replies as handled Signed-off-by: xinjun.jiang <xinjun.jiang@daocloud.io> --------- Signed-off-by: xinjun.jiang <xinjun.jiang@daocloud.io>
2026-10-16 23:35:43 -04:00 · 2026-10-12 12:10:48 +08:00
parent 123829d3b3
commit 13c27392fd
3 changed files with 127 additions and 1 deletions
--- a/test/dns64_test.go
+++ b/test/dns64_test.go
@@ -0,0 +1,86 @@
+package test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/miekg/dns"
+)
+
+func TestDNS64FallbackError(t *testing.T) {
+	for _, rcode := range []int{dns.RcodeSuccess, dns.RcodeServerFailure, dns.RcodeRefused, dns.RcodeFormatError, dns.RcodeNameError, dns.RcodeNotImplemented} {
+		t.Run(dns.RcodeToString[rcode], func(t *testing.T) {
+			corefile := fmt.Sprintf(`.:0 {
+				bind 127.0.0.1
+				dns64 {
+					allow_ipv4
+				}
+				template IN AAAA example.org {
+					rcode NOERROR
+				}
+				template IN A example.org {
+					rcode %s
+				}
+				template IN TXT example.org {
+					answer "{{ .Name }} 60 IN TXT \"connection reused\""
+				}
+			}`, dns.RcodeToString[rcode])
+			i, udp, tcp, err := CoreDNSServerAndPorts(corefile)
+			if err != nil {
+				t.Fatal(err)
+			}
+			t.Cleanup(func() { CoreDNSServerStop(i) })
+
+			for _, transport := range []struct {
+				net  string
+				addr string
+			}{{"udp", udp}, {"tcp", tcp}} {
+				t.Run(transport.net, func(t *testing.T) {
+					client := &dns.Client{Net: transport.net}
+					conn, err := client.Dial(transport.addr)
+					if err != nil {
+						t.Fatal(err)
+					}
+					defer conn.Close()
+
+					for attempt := range 3 {
+						for _, tc := range []struct {
+							qtype uint16
+							id    uint16
+							code  int
+						}{
+							{dns.TypeAAAA, uint16(101 + attempt), rcode},
+							{dns.TypeTXT, uint16(202 + attempt), dns.RcodeSuccess},
+						} {
+							query := new(dns.Msg)
+							query.SetQuestion("example.org.", tc.qtype)
+							query.Id = tc.id
+							if err := conn.SetDeadline(time.Now().Add(2 * time.Second)); err != nil {
+								t.Fatal(err)
+							}
+							if err := conn.WriteMsg(query); err != nil {
+								t.Fatal(err)
+							}
+							response, err := conn.ReadMsg()
+							if err != nil {
+								t.Fatal(err)
+							}
+							if response.Id != query.Id || len(response.Question) != 1 || response.Question[0] != query.Question[0] {
+								t.Fatalf("query ID %d (%s) received an unexpected reply: %s", query.Id, dns.TypeToString[tc.qtype], response)
+							}
+							if response.Rcode != tc.code {
+								t.Errorf("query %s returned %s, want %s", dns.TypeToString[tc.qtype], dns.RcodeToString[response.Rcode], dns.RcodeToString[tc.code])
+							}
+							if tc.qtype == dns.TypeTXT {
+								if len(response.Answer) != 1 || response.Answer[0].String() != "example.org.\t60\tIN\tTXT\t\"connection reused\"" {
+									t.Errorf("connection reuse did not return the TXT answer: %s", response)
+								}
+							}
+						}
+					}
+				})
+			}
+		})
+	}
+}