fix: allow secondary DNS usage when AmneziaDNS is disabled (#1583)

* Allow secondary DNS usage when AmneziaDNS is disabled

* Don't setup secondary DNS for OpenVPN with AmneziaDNS

---------

Co-authored-by: vladimir.kuznetsov <nethiuswork@gmail.com>

client/configurators/openvpn_configurator.cpp

@@ -118,6 +118,12 @@ QString OpenVpnConfigurator::processConfigWithLocalSettings(const QPair<QString,
         QRegularExpression regex("redirect-gateway.*");
         config.replace(regex, "");
         
+        // We don't use secondary DNS if primary DNS is AmneziaDNS
+        if (dns.first.contains(protocols::dns::amneziaDnsIp)) {
+            QRegularExpression dnsRegex("dhcp-option DNS " + dns.second);
+            config.replace(dnsRegex, "");
+        }
+
         if (!m_settings->isSitesSplitTunnelingEnabled()) {
             config.append("\nredirect-gateway def1 ipv6 bypass-dhcp\n");
             config.append("block-ipv6\n");
@@ -161,6 +167,12 @@ QString OpenVpnConfigurator::processConfigWithExportSettings(const QPair<QString
     QRegularExpression regex("redirect-gateway.*");
     config.replace(regex, "");
 
+    // We don't use secondary DNS if primary DNS is AmneziaDNS
+    if (dns.first.contains(protocols::dns::amneziaDnsIp)) {
+        QRegularExpression dnsRegex("dhcp-option DNS " + dns.second);
+        config.replace(dnsRegex, "");
+    }
+
     config.append("\nredirect-gateway def1 ipv6 bypass-dhcp\n");
 
     // Prevent ipv6 leak

client/daemon/daemon.cpp

@@ -169,11 +169,14 @@ bool Daemon::maybeUpdateResolvers(const InterfaceConfig& config) {
   if ((config.m_hopType == InterfaceConfig::MultiHopExit) ||
       (config.m_hopType == InterfaceConfig::SingleHop)) {
     QList<QHostAddress> resolvers;
-    resolvers.append(QHostAddress(config.m_dnsServer));
+    resolvers.append(QHostAddress(config.m_primaryDnsServer));
+    if (!config.m_secondaryDnsServer.isEmpty()) {
+        resolvers.append(QHostAddress(config.m_secondaryDnsServer));
+    }
 
     // If the DNS is not the Gateway, it's a user defined DNS
     // thus, not add any other :)
-    if (config.m_dnsServer == config.m_serverIpv4Gateway) {
+    if (config.m_primaryDnsServer == config.m_serverIpv4Gateway) {
       resolvers.append(QHostAddress(config.m_serverIpv6Gateway));
     }
 
@@ -279,15 +282,26 @@ bool Daemon::parseConfig(const QJsonObject& obj, InterfaceConfig& config) {
   config.m_serverIpv4Gateway = obj.value("serverIpv4Gateway").toString();
   config.m_serverIpv6Gateway = obj.value("serverIpv6Gateway").toString();
 
-  if (!obj.contains("dnsServer")) {
+  if (!obj.contains("primaryDnsServer")) {
-    config.m_dnsServer = QString();
+    config.m_primaryDnsServer = QString();
   } else {
-    QJsonValue value = obj.value("dnsServer");
+    QJsonValue value = obj.value("primaryDnsServer");
     if (!value.isString()) {
       logger.error() << "dnsServer is not a string";
       return false;
     }
-    config.m_dnsServer = value.toString();
+    config.m_primaryDnsServer = value.toString();
+  }
+
+  if (!obj.contains("secondaryDnsServer")) {
+    config.m_secondaryDnsServer = QString();
+  } else {
+    QJsonValue value = obj.value("secondaryDnsServer");
+    if (!value.isString()) {
+      logger.error() << "dnsServer is not a string";
+      return false;
+    }
+    config.m_secondaryDnsServer = value.toString();
   }
 
   if (!obj.contains("hopType")) {

client/daemon/interfaceconfig.cpp

@@ -28,7 +28,8 @@ QJsonObject InterfaceConfig::toJson() const {
       (m_hopType == InterfaceConfig::SingleHop)) {
     json.insert("serverIpv4Gateway", QJsonValue(m_serverIpv4Gateway));
     json.insert("serverIpv6Gateway", QJsonValue(m_serverIpv6Gateway));
-    json.insert("dnsServer", QJsonValue(m_dnsServer));
+    json.insert("primaryDnsServer", QJsonValue(m_primaryDnsServer));
+    json.insert("secondaryDnsServer", QJsonValue(m_secondaryDnsServer));
   }
 
   QJsonArray allowedIPAddesses;
@@ -100,11 +101,15 @@ QString InterfaceConfig::toWgConf(const QMap<QString, QString>& extra) const {
     out << "MTU = " << m_deviceMTU << "\n";
   }
 
-  if (!m_dnsServer.isNull()) {
+  if (!m_primaryDnsServer.isNull()) {
-    QStringList dnsServers(m_dnsServer);
+    QStringList dnsServers;
+    dnsServers.append(m_primaryDnsServer);
+    if (!m_secondaryDnsServer.isNull()) {
+        dnsServers.append(m_secondaryDnsServer);
+    }
     // If the DNS is not the Gateway, it's a user defined DNS
     // thus, not add any other :)
-    if (m_dnsServer == m_serverIpv4Gateway) {
+    if (m_primaryDnsServer == m_serverIpv4Gateway) {
       dnsServers.append(m_serverIpv6Gateway);
     }
     out << "DNS = " << dnsServers.join(", ") << "\n";

client/daemon/interfaceconfig.h

@@ -32,7 +32,8 @@ class InterfaceConfig {
   QString m_serverIpv4AddrIn;
   QString m_serverPskKey;
   QString m_serverIpv6AddrIn;
-  QString m_dnsServer;
+  QString m_primaryDnsServer;
+  QString m_secondaryDnsServer;
   int m_serverPort = 0;
   int m_deviceMTU = 1420;
   QList<IPAddress> m_allowedIPAddressRanges;

client/mozilla/localsocketcontroller.cpp

@@ -149,7 +149,14 @@ void LocalSocketController::activate(const QJsonObject &rawConfig) {
   json.insert("serverPort", wgConfig.value(amnezia::config_key::port).toInt());
   json.insert("serverIpv4Gateway", wgConfig.value(amnezia::config_key::hostName));
   //  json.insert("serverIpv6Gateway", QJsonValue(hop.m_server.ipv6Gateway()));
-  json.insert("dnsServer", rawConfig.value(amnezia::config_key::dns1));
+
+  json.insert("primaryDnsServer", rawConfig.value(amnezia::config_key::dns1));
+
+  // We don't use secondary DNS if primary DNS is AmneziaDNS
+  if (!rawConfig.value(amnezia::config_key::dns1).toString().
+    contains(amnezia::protocols::dns::amneziaDnsIp)) {
+    json.insert("secondaryDnsServer", rawConfig.value(amnezia::config_key::dns2));
+  }
 
   QJsonArray jsAllowedIPAddesses;
 

client/platforms/linux/daemon/wireguardutilslinux.cpp

@@ -140,7 +140,10 @@ bool WireguardUtilsLinux::addInterface(const InterfaceConfig& config) {
     } else {
         if (config.m_killSwitchEnabled) {
             FirewallParams params { };
-            params.dnsServers.append(config.m_dnsServer);
+            params.dnsServers.append(config.m_primaryDnsServer);
+            if (!config.m_secondaryDnsServer.isEmpty()) {
+                params.dnsServers.append(config.m_secondaryDnsServer);
+            }
             if (config.m_allowedIPAddressRanges.contains(IPAddress("0.0.0.0/0"))) {
                 params.blockAll = true;
                 if (config.m_excludedAddresses.size()) {

client/platforms/macos/daemon/wireguardutilsmacos.cpp

@@ -136,26 +136,29 @@ bool WireguardUtilsMacos::addInterface(const InterfaceConfig& config) {
   if (err != 0) {
     logger.error() << "Interface configuration failed:" << strerror(err);
   } else {
-      if (config.m_killSwitchEnabled) {
+    if (config.m_killSwitchEnabled) {
-        FirewallParams params { };
+      FirewallParams params { };
-        params.dnsServers.append(config.m_dnsServer);
+      params.dnsServers.append(config.m_primaryDnsServer);
+      if (!config.m_secondaryDnsServer.isEmpty()) {
+          params.dnsServers.append(config.m_secondaryDnsServer);
+      }
 
-        if (config.m_allowedIPAddressRanges.contains(IPAddress("0.0.0.0/0"))) {
+      if (config.m_allowedIPAddressRanges.contains(IPAddress("0.0.0.0/0"))) {
           params.blockAll = true;
           if (config.m_excludedAddresses.size()) {
-            params.allowNets = true;
+              params.allowNets = true;
-            foreach (auto net, config.m_excludedAddresses) {
+              foreach (auto net, config.m_excludedAddresses) {
-              params.allowAddrs.append(net.toUtf8());
+                  params.allowAddrs.append(net.toUtf8());
-            }
+              }
           }
-        } else {
+      } else {
           params.blockNets = true;
           foreach (auto net, config.m_allowedIPAddressRanges) {
-            params.blockAddrs.append(net.toString());
+              params.blockAddrs.append(net.toString());
           }
-        }
-        applyFirewallRules(params);
       }
+      applyFirewallRules(params);
+    }
   }
   return (err == 0);
 }

client/platforms/windows/daemon/windowsfirewall.cpp

@@ -291,15 +291,32 @@ bool WindowsFirewall::enablePeerTraffic(const InterfaceConfig& config) {
                       "Block Internet", config.m_serverPublicKey)) {
     return false;
   }
-  if (!config.m_dnsServer.isEmpty()) {
+  if (!config.m_primaryDnsServer.isEmpty()) {
-    if (!allowTrafficTo(QHostAddress(config.m_dnsServer), 53, HIGH_WEIGHT,
+    if (!allowTrafficTo(QHostAddress(config.m_primaryDnsServer), 53, HIGH_WEIGHT,
                         "Allow DNS-Server", config.m_serverPublicKey)) {
       return false;
     }
     // In some cases, we might configure a 2nd DNS server for IPv6, however
     // this should probably be cleaned up by converting m_dnsServer into
     // a QStringList instead.
-    if (config.m_dnsServer == config.m_serverIpv4Gateway) {
+    if (config.m_primaryDnsServer == config.m_serverIpv4Gateway) {
+      if (!allowTrafficTo(QHostAddress(config.m_serverIpv6Gateway), 53,
+                          HIGH_WEIGHT, "Allow extra IPv6 DNS-Server",
+                          config.m_serverPublicKey)) {
+        return false;
+      }
+    }
+  }
+
+  if (!config.m_secondaryDnsServer.isEmpty()) {
+    if (!allowTrafficTo(QHostAddress(config.m_secondaryDnsServer), 53, HIGH_WEIGHT,
+                        "Allow DNS-Server", config.m_serverPublicKey)) {
+      return false;
+    }
+    // In some cases, we might configure a 2nd DNS server for IPv6, however
+    // this should probably be cleaned up by converting m_dnsServer into
+    // a QStringList instead.
+    if (config.m_secondaryDnsServer == config.m_serverIpv4Gateway) {
       if (!allowTrafficTo(QHostAddress(config.m_serverIpv6Gateway), 53,
                           HIGH_WEIGHT, "Allow extra IPv6 DNS-Server",
                           config.m_serverPublicKey)) {

client/protocols/xrayprotocol.cpp

@@ -98,8 +98,13 @@ ErrorCode XrayProtocol::startTun2Sock()
         if (vpnState == Vpn::ConnectionState::Connected) {
             setConnectionState(Vpn::ConnectionState::Connecting);
             QList<QHostAddress> dnsAddr;
+
             dnsAddr.push_back(QHostAddress(m_configData.value(config_key::dns1).toString()));
-            dnsAddr.push_back(QHostAddress(m_configData.value(config_key::dns2).toString()));
+            // We don't use secondary DNS if primary DNS is AmneziaDNS
+            if (!m_configData.value(amnezia::config_key::dns1).toString().
+                 contains(amnezia::protocols::dns::amneziaDnsIp)) {
+                dnsAddr.push_back(QHostAddress(m_configData.value(config_key::dns2).toString()));
+            }
 #ifdef Q_OS_WIN
             QThread::msleep(8000);
 #endif

service/server/killswitch.cpp

@@ -192,7 +192,14 @@ bool KillSwitch::addAllowedRange(const QStringList &ranges) {
 bool KillSwitch::enablePeerTraffic(const QJsonObject &configStr) {
 #ifdef Q_OS_WIN
     InterfaceConfig config;
-    config.m_dnsServer = configStr.value(amnezia::config_key::dns1).toString();
+
+    config.m_primaryDnsServer = configStr.value(amnezia::config_key::dns1).toString();
+
+    // We don't use secondary DNS if primary DNS is AmneziaDNS
+    if (!config.m_primaryDnsServer.contains(amnezia::protocols::dns::amneziaDnsIp)) {
+        config.m_secondaryDnsServer = configStr.value(amnezia::config_key::dns2).toString();
+    }
+
     config.m_serverPublicKey = "openvpn";
     config.m_serverIpv4Gateway = configStr.value("vpnGateway").toString();
     config.m_serverIpv4AddrIn = configStr.value("vpnServer").toString();
@@ -307,8 +314,14 @@ bool KillSwitch::enableKillSwitch(const QJsonObject &configStr, int vpnAdapterIn
     LinuxFirewall::setAnchorEnabled(LinuxFirewall::Both, QStringLiteral("300.allowLAN"), true);
     LinuxFirewall::setAnchorEnabled(LinuxFirewall::IPv4, QStringLiteral("310.blockDNS"), true);
     QStringList dnsServers;
+
     dnsServers.append(configStr.value(amnezia::config_key::dns1).toString());
-    dnsServers.append(configStr.value(amnezia::config_key::dns2).toString());
+
+    // We don't use secondary DNS if primary DNS is AmneziaDNS
+    if (!configStr.value(amnezia::config_key::dns1).toString().contains(amnezia::protocols::dns::amneziaDnsIp)) {
+        dnsServers.append(configStr.value(amnezia::config_key::dns2).toString());
+    }
+
     dnsServers.append("127.0.0.1");
     dnsServers.append("127.0.0.53");
     
@@ -345,7 +358,11 @@ bool KillSwitch::enableKillSwitch(const QJsonObject &configStr, int vpnAdapterIn
 
     QStringList dnsServers;
     dnsServers.append(configStr.value(amnezia::config_key::dns1).toString());
-    dnsServers.append(configStr.value(amnezia::config_key::dns2).toString());
+
+    // We don't use secondary DNS if primary DNS is AmneziaDNS
+    if (!configStr.value(amnezia::config_key::dns1).toString().contains(amnezia::protocols::dns::amneziaDnsIp)) {
+        dnsServers.append(configStr.value(amnezia::config_key::dns2).toString());
+    }
     
     for (auto dns : configStr.value(amnezia::config_key::allowedDnsServers).toArray()) {
         if (!dns.isString()) {