Use domain server-assigned WebRTC data channel ID in assignment clients

domain-server/src/DomainServer.cpp

@@ -891,7 +891,16 @@ void DomainServer::routeWebRTCSignalingMessage(const QJsonObject& json) {
     if (json.value("to").toString() == NodeType::DomainServer) {
         emit webrtcSignalingMessageForDomainServer(json);
     } else {
-        sendWebRTCSignalingMessageToAssignmentClient(json);
+        // Insert the WebRTC data channel ID for the assignment client to use.
+        auto webrtcSocket = DependencyManager::get<LimitedNodeList>()->getWebRTCSocket();
+        auto channelID = webrtcSocket->getDataChannelIDForWebSocket((quint16)json.value("from").toInt());
+        if (channelID == 0 && json.value("echo").isUndefined()) {  // Let echo messages through without a domain connection.
+            qCritical() << "WebRTC data channel ID not found for assignment client signaling!";
+            return;
+        }
+        QJsonObject jsonModified = json;
+        jsonModified.insert("channel", QJsonValue(channelID));
+        sendWebRTCSignalingMessageToAssignmentClient(jsonModified);
     }
 }
 

libraries/networking/src/webrtc/WebRTCDataChannels.cpp

@@ -131,12 +131,13 @@ void WDCDataChannelObserver::OnMessage(const DataBuffer& buffer) {
 }
 
 
-WDCConnection::WDCConnection(WebRTCDataChannels* parent, quint16 webSocketID) :
+WDCConnection::WDCConnection(WebRTCDataChannels* parent, quint16 webSocketID, int dataChannelID) :
     _parent(parent),
-    _webSocketID(webSocketID)
+    _webSocketID(webSocketID),
+    _dataChannelID(dataChannelID)
 {
 #ifdef WEBRTC_DEBUG
-    qCDebug(networking_webrtc) << "WDCConnection::WDCConnection() :" << webSocketID;
+    qCDebug(networking_webrtc) << "WDCConnection::WDCConnection() :" << webSocketID << dataChannelID;
 #endif
 
     // Create observers.
@@ -288,7 +289,6 @@ void WDCConnection::onDataChannelOpened(rtc::scoped_refptr<DataChannelInterface>
 #endif
 
     _dataChannel = dataChannel;
-    _dataChannelID = _parent->getNewDataChannelID();  // Not dataChannel->id() because it's only unique per peer connection.
     _dataChannel->RegisterObserver(_dataChannelObserver.get());
 
 #ifdef WEBRTC_DEBUG
@@ -432,9 +432,23 @@ void WebRTCDataChannels::reset() {
 quint16 WebRTCDataChannels::getNewDataChannelID() {
     static const int QUINT16_LIMIT = std::numeric_limits<uint16_t>::max() + 1;
     _lastDataChannelID = std::max((_lastDataChannelID + 1) % QUINT16_LIMIT, 1);
+#ifdef WEBRTC_DEBUG
+    qCDebug(networking_webrtc) << "WebRTCDataChannels::getNewDataChannelID() :" << _lastDataChannelID;
+#endif
     return _lastDataChannelID;
 }
 
+int WebRTCDataChannels::getDataChannelIDForWebSocket(quint16 webSocketID) const {
+#ifdef WEBRTC_DEBUG
+    qCDebug(networking_webrtc) << "WebRTCDataChannels::getDataChannelIDForWebSocket() :" << webSocketID;
+#endif
+    auto connection = _connectionsByWebSocket.value(webSocketID);
+    if (!connection) {
+        return 0;
+    }
+    return connection->getDataChannelID();
+}
+
 void WebRTCDataChannels::onDataChannelOpened(WDCConnection* connection, quint16 dataChannelID) {
 #ifdef WEBRTC_DEBUG
     qCDebug(networking_webrtc) << "WebRTCDataChannels::onDataChannelOpened() :" << dataChannelID;
@@ -444,7 +458,7 @@ void WebRTCDataChannels::onDataChannelOpened(WDCConnection* connection, quint16
 
 void WebRTCDataChannels::onSignalingMessage(const QJsonObject& message) {
 #ifdef WEBRTC_DEBUG
-    qCDebug(networking_webrtc) << "WebRTCDataChannel::onSignalingMessage()" << message;
+    qCDebug(networking_webrtc) << "WebRTCDataChannel::onSignalingMessage()" << message << message.value("channel");
 #endif
 
     // Validate message.
@@ -452,8 +466,9 @@ void WebRTCDataChannels::onSignalingMessage(const QJsonObject& message) {
     auto data = message.value("data").isObject() ? message.value("data").toObject() : QJsonObject();
     int from = message.value("from").isDouble() ? (quint16)(message.value("from").toInt()) : 0;
     auto to = NodeType::fromChar(message.value("to").toString().at(0));
+    int channel = message.value("channel").isDouble() ? (int)(message.value("channel").toInt()) : 0;
 
-    if (from <= 0 || from > MAXUINT16 || to == NodeType::Unassigned
+    if (from <= 0 || from > MAXUINT16 || to == NodeType::Unassigned || channel < 0 || channel > MAXUINT16
             || !data.contains("description") && !data.contains("candidate")) {
         qCWarning(networking_webrtc) << "Unexpected signaling message:"
             << QJsonDocument(message).toJson(QJsonDocument::Compact).left(MAX_DEBUG_DETAIL_LENGTH);
@@ -468,7 +483,12 @@ void WebRTCDataChannels::onSignalingMessage(const QJsonObject& message) {
     if (_connectionsByWebSocket.contains(from)) {
         connection = _connectionsByWebSocket.value(from);
     } else {
-        connection = new WDCConnection(this, from);
+        // Assignment clients use the same data channel ID as the domain server, which is provided in the "channel" property.
+        // The domain server creates a new data channel ID.
+        if (channel == 0) {
+            channel = getNewDataChannelID();  
+        }
+        connection = new WDCConnection(this, from, channel);
         _connectionsByWebSocket.insert(from, connection);
     }
 

libraries/networking/src/webrtc/WebRTCDataChannels.h

@@ -129,7 +129,8 @@ public:
     /// @brief Constructs a new WDCConnection and opens a WebRTC data connection.
     /// @param parent The parent WebRTCDataChannels object.
     /// @param webSocketID The signaling channel that initiated the opening of the WebRTC data channel.
-    WDCConnection(WebRTCDataChannels* parent, quint16 webSocketID);
+    /// @param dataChannelID - The WebRTC data channel ID to assign to this connection.
+    WDCConnection(WebRTCDataChannels* parent, quint16 webSocketID, int dataChannelID);
 
     /// @brief Gets the WebSocket ID.
     /// @return The ID of the WebSocket.
@@ -241,12 +242,17 @@ public:
     /// @brief Immediately closes all connections and resets the socket.
     void reset();
     
-    /// @brief Get a new data channel ID to uniquely identify a WDCConnection.
+    /// @brief Gets a new data channel ID to uniquely identify a WDCConnection.
     /// @details This ID is assigned by WebRTCDataChannels; it is <em>not</em> the WebRTC data channel ID because that is only
     ///     unique within a peer connection.
     /// @return A new data channel ID.
     quint16 getNewDataChannelID();
 
+    /// @brief Gets the data channel ID associated with a WebSocket.
+    /// @param webSocketID The WebSocket.
+    /// @return The data channel ID associated with the WebSocket if found, `0` if the WebSocket was not found.
+    int getDataChannelIDForWebSocket(quint16 webSocketID) const;
+
     /// @brief Handles a WebRTC data channel opening.
     /// @param connection The WebRTC data channel connection.
     /// @param dataChannelID The WebRTC data channel ID.

libraries/networking/src/webrtc/WebRTCSocket.cpp

@@ -153,4 +153,9 @@ void WebRTCSocket::onDataChannelReceivedMessage(int dataChannelID, const QByteAr
     emit readyRead();
 }
 
+
+int WebRTCSocket::getDataChannelIDForWebSocket(quint16 webSocketID) const {
+    return _dataChannels.getDataChannelIDForWebSocket(webSocketID);
+}
+
 #endif // WEBRTC_DATA_CHANNELS

libraries/networking/src/webrtc/WebRTCSocket.h

@@ -120,6 +120,12 @@ public:
     /// @return The description of the error that last occurred.
     QString errorString() const;
 
+
+    /// @brief Gets the data channel ID associated with a WebSocket.
+    /// @param webSocketID
+    /// @return The data channel ID associated with the WebSocket if found, `0` if the WebSocket was not found.
+    int getDataChannelIDForWebSocket(quint16 webSocketID) const;
+
 public slots:
 
     /// @brief Handles the WebRTC data channel receiving a message.