send the mac address with domain-server check in

domain-server/src/NodeConnectionData.cpp

@@ -29,6 +29,9 @@ NodeConnectionData NodeConnectionData::fromDataStream(QDataStream& dataStream, c
 
         // NOTE: QDataStream::readBytes() - The buffer is allocated using new []. Destroy it with the delete [] operator.
         delete[] rawBytes;
+
+        // read the hardware address sent by the client
+        dataStream >> newHeader.hardwareAddress;
     }
     
     dataStream >> newHeader.nodeType

domain-server/src/NodeConnectionData.h

@@ -28,6 +28,7 @@ public:
     HifiSockAddr senderSockAddr;
     QList<NodeType_t> interestList;
     QString placeName;
+    QString hardwareAddress;
 
     QByteArray protocolVersion;
 };

libraries/networking/src/NodeList.cpp

@@ -18,6 +18,7 @@
 #include <QtCore/QUrl>
 #include <QtCore/QThread>
 #include <QtNetwork/QHostInfo>
+#include <QtNetwork/QNetworkInterface>
 
 #include <LogHandler.h>
 #include <UUID.h>
@@ -346,6 +347,28 @@ void NodeList::sendDomainServerCheckIn() {
             // include the protocol version signature in our connect request
             QByteArray protocolVersionSig = protocolVersionsSignature();
             packetStream.writeBytes(protocolVersionSig.constData(), protocolVersionSig.size());
+
+            // if possible, include the MAC address for the current interface in our connect request
+            QString hardwareAddress;
+
+            for (auto networkInterface : QNetworkInterface::allInterfaces()) {
+                for (auto interfaceAddress : networkInterface.addressEntries()) {
+                    if (interfaceAddress.ip() == _localSockAddr.getAddress()) {
+                        // this is the interface whose local IP matches what we've detected the current IP to be
+                        hardwareAddress = networkInterface.hardwareAddress();
+
+                        // stop checking interfaces and addresses
+                        break;
+                    }
+                }
+
+                // stop looping if this was the current interface
+                if (!hardwareAddress.isEmpty()) {
+                    break;
+                }
+            }
+
+            packetStream << hardwareAddress;
         }
 
         // pack our data to send to the domain-server including

libraries/networking/src/udt/PacketHeaders.cpp

@@ -67,7 +67,7 @@ PacketVersion versionForPacketType(PacketType packetType) {
             return static_cast<PacketVersion>(DomainConnectionDeniedVersion::IncludesExtraInfo);
 
         case PacketType::DomainConnectRequest:
-            return static_cast<PacketVersion>(DomainConnectRequestVersion::HasProtocolVersions);
+            return static_cast<PacketVersion>(DomainConnectRequestVersion::HasMACAddress);
 
         case PacketType::DomainServerAddedNode:
             return static_cast<PacketVersion>(DomainServerAddedNodeVersion::PermissionsGrid);

libraries/networking/src/udt/PacketHeaders.h

@@ -207,7 +207,8 @@ enum class AvatarMixerPacketVersion : PacketVersion {
 enum class DomainConnectRequestVersion : PacketVersion {
     NoHostname = 17,
     HasHostname,
-    HasProtocolVersions
+    HasProtocolVersions,
+    HasMACAddress
 };
 
 enum class DomainConnectionDeniedVersion : PacketVersion {