Here are the data structures with brief descriptions:

Cab_ga_il_route_cmd_t	Decoded RBC_MSG_IL_ROUTE_CMD payload
Cab_ga_il_route_indication_t	RBC_MSG_IL_ROUTE_INDICATION payload (RBC -> IL)
Cab_ga_il_status_msg_t	Decoded RBC_MSG_IL_STATUS payload
Cab_ga_route_fsm_result_t	Result of applying one IL route command to a route's FSM
Cab_ga_shunting_context_t
Cab_site_ga_route_layout_t	One route's static layout entry (railML interlocking <route>) - GA's own full definition (not a reduced projection of anyone else's table - GA is the sole owner of route topology now)
Cga_channel_ctx_t
Cgateway_c_ctc_handler_state_t
Cgateway_c_il_handler_state_t
Cil_pending_route_event_t	Queued route event for IL notification dispatch