How to get GAP address from unicast address of mesh node

Hi teams,

I want to find GAP address of sending node after received message.

In client model callback, there is access_message_rx_meta_t argument, and I can get unicast address of sender node by src.value member.

Now I need to know the GAP address of sender node. How I can get this value?

I already tried nrf_mesh_rx_metadata_t, but it has the GAP address of the relay node, not the original sender.