feat: add DNS endpoint of Google Kubernetes Engine cluster control plane

feat: add more detailed drop causes to corresponding enum

docs: update outdated comments
PiperOrigin-RevId: 694367344

google/cloud/networkmanagement/v1/connectivity_test.proto

@@ -220,10 +220,16 @@ message Endpoint {
   optional LoadBalancerType load_balancer_type = 16
       [(google.api.field_behavior) = OUTPUT_ONLY];
 
-  // A cluster URI for [Google Kubernetes Engine
-  // master](https://cloud.google.com/kubernetes-engine/docs/concepts/cluster-architecture).
+  // A cluster URI for [Google Kubernetes Engine cluster control
+  // plane](https://cloud.google.com/kubernetes-engine/docs/concepts/cluster-architecture).
   string gke_master_cluster = 7;
 
+  // DNS endpoint of [Google Kubernetes Engine cluster control
+  // plane](https://cloud.google.com/kubernetes-engine/docs/concepts/cluster-architecture).
+  // Requires gke_master_cluster to be set, can't be used simultaneoulsly with
+  // ip_address or network. Applicable only to destination endpoint.
+  string fqdn = 19;
+
   // A [Cloud SQL](https://cloud.google.com/sql) instance URI.
   string cloud_sql_instance = 8;
 

google/cloud/networkmanagement/v1/trace.proto

@@ -1482,6 +1482,10 @@ message DropInfo {
     // Packet from the unknown peered network is dropped due to no known route
     // from the source network to the destination IP address.
     NO_KNOWN_ROUTE_FROM_PEERED_NETWORK_TO_DESTINATION = 82;
+
+    // Sending packets processed by the Private NAT Gateways to the Private
+    // Service Connect endpoints is not supported.
+    PRIVATE_NAT_TO_PSC_ENDPOINT_UNSUPPORTED = 83;
   }
 
   // Cause that the packet is dropped.
@@ -1509,11 +1513,14 @@ message GKEMasterInfo {
   // URI of a GKE cluster network.
   string cluster_network_uri = 4;
 
-  // Internal IP address of a GKE cluster master.
+  // Internal IP address of a GKE cluster control plane.
   string internal_ip = 5;
 
-  // External IP address of a GKE cluster master.
+  // External IP address of a GKE cluster control plane.
   string external_ip = 6;
+
+  // DNS endpoint of a GKE cluster control plane.
+  string dns_endpoint = 7;
 }
 
 // For display only. Metadata associated with a Cloud SQL instance.