From 5a7f99b44b6debc8e5ebe167357cb88df90a73ed Mon Sep 17 00:00:00 2001
From: bert hubert <bert.hubert@netherlabs.nl>
Date: Fri, 5 Oct 2018 15:25:59 +0200
Subject: [PATCH] emit a /0 ECS response on non-variable answers when using
 use-incoming-ecs, for the eventual benefit of dnsdist

---
 pdns/pdns_recursor.cc | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/pdns/pdns_recursor.cc b/pdns/pdns_recursor.cc
index 19a28408f2..67ea44375f 100644
--- a/pdns/pdns_recursor.cc
+++ b/pdns/pdns_recursor.cc
@@ -1486,6 +1486,17 @@ static void startDoResolve(void *p)
     }
   sendit:;
 
+    if(g_useIncomingECS && haveEDNS && !sr.wasVariable()) {
+      EDNSSubnetOpts eo;
+      eo.source = dc->d_ednssubnet.source;
+      ComboAddress sa;
+      memset(&sa, 0, sizeof(sa));
+      sa.sin4.sin_family = eo.source.getNetwork().sin4.sin_family;
+      eo.scope = Netmask(sa, 0);
+
+      returnedEdnsOptions.push_back(make_pair(EDNSOptionCode::ECS, makeEDNSSubnetOptsString(eo)));
+    }
+
     if (haveEDNS) {
       /* we try to add the EDNS OPT RR even for truncated answers,
          as rfc6891 states:
-- 
2.39.5