nas: make state variables atomics

NAS states and substates maybe be requested from other threads so
they need to be protected.

Note that the caller still needs to hold it's own mutex if different
actions are required based on the state.

srsue/hdr/stack/upper/nas_5gmm_state.h

@@ -75,8 +75,8 @@ public:
 
 private:
   std::atomic<state_t>    state{state_t::null};
-  deregistered_substate_t deregistered_substate = deregistered_substate_t::null;
-  registered_substate_t   registered_substate   = registered_substate_t::null;
+  std::atomic<deregistered_substate_t> deregistered_substate{deregistered_substate_t::null};
+  std::atomic<registered_substate_t>   registered_substate{registered_substate_t::null};
   srslog::basic_logger&   logger                = srslog::fetch_basic_logger("NAS-5G");
 };
 
@@ -85,4 +85,5 @@ const char* mm5g_deregistered_substate_text(mm5g_state_t::deregistered_substate_
 const char* mm5g_registered_substate_text(mm5g_state_t::registered_substate_t type);
 
 } // namespace srsue
+
 #endif

srsue/hdr/stack/upper/nas_emm_state.h

@@ -78,8 +78,8 @@ public:
 
 private:
   std::atomic<state_t> state{state_t::null}; // The GW might require to know the NAS state from another thread
-  deregistered_substate_t deregistered_substate = deregistered_substate_t::null;
-  registered_substate_t   registered_substate   = registered_substate_t::null;
+  std::atomic<deregistered_substate_t> deregistered_substate{deregistered_substate_t::null};
+  std::atomic<registered_substate_t>   registered_substate{registered_substate_t::null};
   srslog::basic_logger&                logger = srslog::fetch_basic_logger("NAS");
 };
 
@@ -88,4 +88,5 @@ const char* emm_deregistered_substate_text(emm_state_t::deregistered_substate_t
 const char* emm_registered_substate_text(emm_state_t::registered_substate_t type);
 
 } // namespace srsue
+
 #endif