Bound local discovery traffic and validate invitations

tools/chatgui/src/mainwindow.cpp

@@ -449,10 +449,14 @@ void MainWindow::setupBridgeCallbacks() {
         QString name = QString::fromUtf8((const char*)data + 9, data[8]);
         QString link = QString::fromUtf8((const char*)data + 9 + data[8], len - 9 - data[8]);
         auto* window = s_mainWindow;
+        if (window->findChildren<QMessageBox*>(QStringLiteral("localInvitePrompt")).size() >= 8) {
+            DEBUG_WARN(DEBUG_CATEGORY_DISCOVERY, "incoming local invitation prompt limit reached"); return;
+        }
         auto* prompt = new QMessageBox(QMessageBox::Question, QCoreApplication::translate("ChatGui", "Invitation"),
             QCoreApplication::translate("ChatGui", "%1 sent an invitation over the local network. Connect?").arg(name),
             QMessageBox::Yes | QMessageBox::No, window);
         prompt->setTextFormat(Qt::PlainText); prompt->setAttribute(Qt::WA_DeleteOnClose);
+        prompt->setObjectName(QStringLiteral("localInvitePrompt"));
         QObject::connect(prompt, &QMessageBox::finished, window, [window, link](int result) {
             if (result == QMessageBox::Yes) window->onMessageLinkActivated(link);
         });