If we get NODATA on an AAAA in followCNAMERecords, try dns64

Fixes #11320

diff --git a/pdns/pdns_recursor.cc b/pdns/pdns_recursor.cc
index 9aad7e01eeddbe8c0fe2cbf671064c2f25c86be8..29298cd19c15cde06f437d275fec200a4dc3b2c3 100644 (file)
--- a/pdns/pdns_recursor.cc
+++ b/pdns/pdns_recursor.cc
@@ -613,6 +613,8 @@ static bool udrCheckUniqueDNSRecord(const shared_ptr<Logr::Logger>& nodlogger, c
 }
 #endif /* NOD_ENABLED */
 
+static bool answerIsNOData(uint16_t requestedType, int rcode, const std::vector<DNSRecord>& records);
+
 int followCNAMERecords(vector<DNSRecord>& ret, const QType qtype, int rcode)
 {
   vector<DNSRecord> resolved;
@@ -633,8 +635,14 @@ int followCNAMERecords(vector<DNSRecord>& ret, const QType qtype, int rcode)
 
   rcode = directResolve(target, qtype, QClass::IN, resolved, t_pdl);
 
+  if (g_dns64Prefix && qtype == QType::AAAA && answerIsNOData(qtype, rcode, resolved)) {
+    rcode = getFakeAAAARecords(target, *g_dns64Prefix, resolved);
+  }
+
   for (DNSRecord& rr : resolved) {
-    ret.push_back(std::move(rr));
+    if (rr.d_place == DNSResourceRecord::ANSWER) {
+      ret.push_back(std::move(rr));
+    }
   }
   return rcode;
 }