From af8824af3546d78a9bf42b35f18f78e310e53946 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Mon, 23 Apr 2018 11:26:04 +0200
Subject: [PATCH] bug 1455972 - make TRR prefer address responses to CNAME
 r=mcmanus

In a DOH response to a query asking for an A or AAAA record, a CNAME
response is often accompanied by A/AAAA resources as well. With this
change, TRR now rather use those address records than following the
CNAME record. This saves name resolver round-trips.

MozReview-Commit-ID: GcjZj5Ehz68

--HG--
extra : rebase_source : b80d9818cb8fa6139feeeec3d2fb11a5b800ee48
---
 netwerk/dns/TRR.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/netwerk/dns/TRR.cpp b/netwerk/dns/TRR.cpp
index da7b59bf9568..fe7c0e90f5e8 100644
--- a/netwerk/dns/TRR.cpp
+++ b/netwerk/dns/TRR.cpp
@@ -819,7 +819,7 @@ TRR::On200Response()
   nsresult rv = DohDecode();
 
   if (NS_SUCCEEDED(rv)) {
-    if (!mCname.IsEmpty()) {
+    if (!mDNS.mAddresses.getFirst() && !mCname.IsEmpty()) {
       if (!--mCnameLoop) {
         LOG(("TRR::On200Response CNAME loop, eject!\n"));
       } else  {