From: Dmitry Alenichev <mitya@vk.com>
Date: Thu, 14 Feb 2019 15:02:49 +0000 (+0300)
Subject: make passing empty response optional
X-Git-Tag: auth-4.2.0-beta1~4^2~6
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=0dffe9e319dcacc725ceb621f1dbc3a1903f31d0;p=pdns

make passing empty response optional
---

diff --git a/pdns/dnsdist-lua.cc b/pdns/dnsdist-lua.cc
index 49bdde30e..5af04951c 100644
--- a/pdns/dnsdist-lua.cc
+++ b/pdns/dnsdist-lua.cc
@@ -1761,6 +1761,8 @@ void setupLuaConfig(bool client)
         }
 #endif
       });
+
+  g_lua.writeFunction("setAllowEmptyResponse", [](bool allow) { g_allowEmptyResponse=allow; });
 }
 
 vector<std::function<void(void)>> setupLua(bool client, const std::string& config)
diff --git a/pdns/dnsdist-web.cc b/pdns/dnsdist-web.cc
index 8cd977384..82d441960 100644
--- a/pdns/dnsdist-web.cc
+++ b/pdns/dnsdist-web.cc
@@ -697,6 +697,7 @@ static void connectionThread(int sock, ComboAddress remote)
       typedef boost::variant<bool, double, std::string> configentry_t;
       std::vector<std::pair<std::string, configentry_t> > configEntries {
         { "acl", g_ACL.getLocal()->toString() },
+        { "allow-empty-response", g_allowEmptyResponse },
         { "control-socket", g_serverControl.toStringWithPort() },
         { "ecs-override", g_ECSOverride },
         { "ecs-source-prefix-v4", (double) g_ECSSourcePrefixV4 },
diff --git a/pdns/dnsdist.cc b/pdns/dnsdist.cc
index 49a0dc27a..ecdace0b0 100644
--- a/pdns/dnsdist.cc
+++ b/pdns/dnsdist.cc
@@ -87,6 +87,7 @@ uint16_t g_maxOutstanding{10240};
 bool g_verboseHealthChecks{false};
 uint32_t g_staleCacheEntriesTTL{0};
 bool g_syslog{true};
+bool g_allowEmptyResponse{false};
 
 GlobalStateHolder<NetmaskGroup> g_ACL;
 string g_outputBuffer;
@@ -222,7 +223,7 @@ bool responseContentMatches(const char* response, const uint16_t responseLen, co
   }
 
   if (dh->qdcount == 0) {
-    if (dh->rcode != RCode::NXDomain) {
+    if (dh->rcode != RCode::NXDomain && g_allowEmptyResponse) {
       return true;
     }
     else {
diff --git a/pdns/dnsdist.hh b/pdns/dnsdist.hh
index 8b36320f6..612a96ec6 100644
--- a/pdns/dnsdist.hh
+++ b/pdns/dnsdist.hh
@@ -958,6 +958,7 @@ extern bool g_useTCPSinglePipe;
 extern std::atomic<uint16_t> g_downstreamTCPCleanupInterval;
 extern size_t g_udpVectorSize;
 extern bool g_preserveTrailingData;
+extern bool g_allowEmptyResponse;
 
 #ifdef HAVE_EBPF
 extern shared_ptr<BPFFilter> g_defaultBPFFilter;