listener: support update socket_options (#23189)

Fixes #22634

Signed-off-by: He Jie Xu <hejie.xu@intel.com>

Mirrored from https://github.com/envoyproxy/envoy @ 9201b93425f9ef0e0d2a37eafbdcd99548dc8db4

envoy/config/listener/v3/listener.proto

@@ -243,7 +243,10 @@ message Listener {
   google.protobuf.BoolValue freebind = 11;
 
   // Additional socket options that may not be present in Envoy source code or
-  // precompiled binaries.
+  // precompiled binaries. The socket options can be updated for a listener when
+  // :ref:`enable_reuse_port <envoy_v3_api_field_config.listener.v3.Listener.enable_reuse_port>`
+  // is `true`. Otherwise, if socket options change during a listener update the update will be rejected
+  // to make it clear that the options were not updated.
   repeated core.v3.SocketOption socket_options = 13;
 
   // Whether the listener should accept TCP Fast Open (TFO) connections.
@@ -309,7 +312,9 @@ message Listener {
   // create one socket for each worker thread. This makes inbound connections
   // distribute among worker threads roughly evenly in cases where there are a high number
   // of connections. When this flag is set to false, all worker threads share one socket. This field
-  // defaults to true.
+  // defaults to true. The change of field will be rejected during an listener update when the
+  // runtime flag ``envoy.reloadable_features.enable_update_listener_socket_options`` is enabled.
+  // Otherwise, the update of this field will be ignored quietly.
   //
   // .. attention::
   //