Check for capability feature "federation-v2" for federated connections.

capabilities.go

@@ -41,6 +41,9 @@ const (
 	// Name of capability to enable the "v3" API for the signaling endpoint.
 	FeatureSignalingV3Api = "signaling-v3"
 
+	// Name of capability that is set if the server supports Federation V2.
+	FeatureFederationV2 = "federation-v2"
+
 	// Cache received capabilities for one hour.
 	CapabilitiesCacheDuration = time.Hour
 

hub.go

@@ -1282,6 +1282,10 @@ func (h *Hub) processHelloV2(ctx context.Context, client HandlerClient, message
 		tokenString = message.Hello.Auth.helloV2Params.Token
 		tokenClaims = &HelloV2TokenClaims{}
 	case HelloClientTypeFederation:
+		if !h.backend.capabilities.HasCapabilityFeature(ctx, url, FeatureFederationV2) {
+			return nil, nil, ErrFederationNotSupported
+		}
+
 		tokenString = message.Hello.Auth.federationParams.Token
 		tokenClaims = &FederationTokenClaims{}
 	default:

hub_test.go

@@ -699,6 +699,9 @@ func registerBackendHandlerUrl(t *testing.T, router *mux.Router, url string) {
 		if strings.Contains(t.Name(), "V3Api") {
 			features = append(features, "signaling-v3")
 		}
+		if strings.Contains(t.Name(), "Federation") {
+			features = append(features, "federation-v2")
+		}
 		signaling := map[string]interface{}{
 			"foo": "bar",
 			"baz": 42,