From: Pieter Lexis <pieter.lexis@powerdns.com>
Date: Tue, 5 Mar 2019 15:45:35 +0000 (+0100)
Subject: DNAME: skip one unneeded cache lookup
X-Git-Tag: rec-4.2.0-beta1~6^2~12
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=71e9cc53742cf57571276f484d21e0606e077ceb;p=thirdparty%2Fpdns.git

DNAME: skip one unneeded cache lookup
---

diff --git a/pdns/syncres.cc b/pdns/syncres.cc
index 28216fbb0e..81fa469160 100644
--- a/pdns/syncres.cc
+++ b/pdns/syncres.cc
@@ -952,13 +952,14 @@ bool SyncRes::doCNAMECacheCheck(const DNSName &qname, const QType &qtype, vector
     do {
       dnameName.prependRawLabel(labels.back());
       labels.pop_back();
+      if (dnameName == qname && qtype != QType::DNAME) { // The client does not want a DNAME, but we've reached the QNAME already. So there is no match
+        break;
+      }
       LOG(prefix<<qname<<": Looking for DNAME cache hit of '"<<dnameName<<"|DNAME"<<"'"<<endl);
       if (t_RC->get(d_now.tv_sec, dnameName, QType(QType::DNAME), !wasForwardRecurse && d_requireAuthData, &cset, d_cacheRemote, d_doDNSSEC ? &signatures : nullptr, d_doDNSSEC ? &authorityRecs : nullptr, &d_wasVariable, &state, &wasAuth) > 0) {
-        if (dnameName != qname && qtype != QType::DNAME) {
-          foundName = dnameName;
-          foundQT = QType(QType::DNAME);
-          break;
-        }
+        foundName = dnameName;
+        foundQT = QType(QType::DNAME);
+        break;
       }
     } while(!labels.empty());
   }