From a726a40dc552bae23f545e73f5d42fab3ea1af68 Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Sat, 23 Feb 2019 00:58:25 +0100
Subject: [PATCH] Add refused_code_in_responses

Fixes #737
---
 dnscrypt-proxy/config.go   |  3 +++
 dnscrypt-proxy/dnsutils.go |  8 ++++++--
 dnscrypt-proxy/plugins.go  | 12 +++++++-----
 dnscrypt-proxy/proxy.go    |  1 +
 4 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/dnscrypt-proxy/config.go b/dnscrypt-proxy/config.go
index c48e2d5a..d9d9fdee 100644
--- a/dnscrypt-proxy/config.go
+++ b/dnscrypt-proxy/config.go
@@ -73,6 +73,7 @@ type Config struct {
 	NetprobeTimeout          int                        `toml:"netprobe_timeout"`
 	OfflineMode              bool                       `toml:"offline_mode"`
 	HTTPProxyURL             string                     `toml:"http_proxy"`
+	RefusedCodeInResponses   bool                       `toml:"refused_code_in_responses"`
 }
 
 func newConfig() Config {
@@ -108,6 +109,7 @@ func newConfig() Config {
 		NetprobeAddress:          "9.9.9.9:53",
 		NetprobeTimeout:          60,
 		OfflineMode:              false,
+		RefusedCodeInResponses:   false,
 	}
 }
 
@@ -278,6 +280,7 @@ func ConfigLoad(proxy *Proxy, svcFlag *string) error {
 
 	proxy.xTransport.rebuildTransport()
 
+	proxy.refusedCodeInResponses = config.RefusedCodeInResponses
 	proxy.timeout = time.Duration(config.Timeout) * time.Millisecond
 	proxy.maxClients = config.MaxClients
 	proxy.mainProto = "udp"
diff --git a/dnscrypt-proxy/dnsutils.go b/dnscrypt-proxy/dnsutils.go
index e8c5e214..0c1cc61c 100644
--- a/dnscrypt-proxy/dnsutils.go
+++ b/dnscrypt-proxy/dnsutils.go
@@ -31,12 +31,16 @@ func EmptyResponseFromMessage(srcMsg *dns.Msg) (*dns.Msg, error) {
 	return dstMsg, nil
 }
 
-func RefusedResponseFromMessage(srcMsg *dns.Msg) (*dns.Msg, error) {
+func RefusedResponseFromMessage(srcMsg *dns.Msg, refusedCode bool) (*dns.Msg, error) {
 	dstMsg, err := EmptyResponseFromMessage(srcMsg)
 	if err != nil {
 		return dstMsg, err
 	}
-	dstMsg.Rcode = dns.RcodeRefused
+	if refusedCode {
+		dstMsg.Rcode = dns.RcodeRefused
+	} else {
+		dstMsg.Rcode = dns.RcodeSuccess
+	}
 	return dstMsg, nil
 }
 
diff --git a/dnscrypt-proxy/plugins.go b/dnscrypt-proxy/plugins.go
index 73bbf32a..56bc59ce 100644
--- a/dnscrypt-proxy/plugins.go
+++ b/dnscrypt-proxy/plugins.go
@@ -21,9 +21,10 @@ const (
 
 type PluginsGlobals struct {
 	sync.RWMutex
-	queryPlugins    *[]Plugin
-	responsePlugins *[]Plugin
-	loggingPlugins  *[]Plugin
+	queryPlugins           *[]Plugin
+	responsePlugins        *[]Plugin
+	loggingPlugins         *[]Plugin
+	refusedCodeInResponses bool
 }
 
 type PluginsReturnCode int
@@ -127,6 +128,7 @@ func InitPluginsGlobals(pluginsGlobals *PluginsGlobals, proxy *Proxy) error {
 	(*pluginsGlobals).queryPlugins = queryPlugins
 	(*pluginsGlobals).responsePlugins = responsePlugins
 	(*pluginsGlobals).loggingPlugins = loggingPlugins
+	(*pluginsGlobals).refusedCodeInResponses = proxy.refusedCodeInResponses
 	return nil
 }
 
@@ -175,7 +177,7 @@ func (pluginsState *PluginsState) ApplyQueryPlugins(pluginsGlobals *PluginsGloba
 			return packet, ret
 		}
 		if pluginsState.action == PluginsActionReject {
-			synth, err := RefusedResponseFromMessage(&msg)
+			synth, err := RefusedResponseFromMessage(&msg, pluginsGlobals.refusedCodeInResponses)
 			if err != nil {
 				return nil, err
 			}
@@ -223,7 +225,7 @@ func (pluginsState *PluginsState) ApplyResponsePlugins(pluginsGlobals *PluginsGl
 			return packet, ret
 		}
 		if pluginsState.action == PluginsActionReject {
-			synth, err := RefusedResponseFromMessage(&msg)
+			synth, err := RefusedResponseFromMessage(&msg, pluginsGlobals.refusedCodeInResponses)
 			if err != nil {
 				return nil, err
 			}
diff --git a/dnscrypt-proxy/proxy.go b/dnscrypt-proxy/proxy.go
index c41cf404..9e62dbe5 100644
--- a/dnscrypt-proxy/proxy.go
+++ b/dnscrypt-proxy/proxy.go
@@ -63,6 +63,7 @@ type Proxy struct {
 	logMaxSize                   int
 	logMaxAge                    int
 	logMaxBackups                int
+	refusedCodeInResponses       bool
 }
 
 func (proxy *Proxy) StartProxy() {