Introduced 5GMM state machine

* according to 5.1.3.2.1 of 3GPP TS 24.501

openair3/NAS/NR_UE/nr_nas_msg_sim.c

@@ -478,7 +478,8 @@ void generateRegistrationRequest(as_nas_info_t *initialNasMsg, nr_ue_nas_t *nas)
 
   initialNasMsg->length = mm_msg_encode(mm_msg, (uint8_t*)(initialNasMsg->data), size);
   registration_request_len = initialNasMsg->length;
-
+  /* set NAS 5GMM state */
+  nas->fiveGMM_state = FGS_REGISTERED_INITIATED;
 }
 
 void generateIdentityResponse(as_nas_info_t *initialNasMsg, uint8_t identitytype, uicc_t* uicc) {
@@ -717,6 +718,8 @@ static void generateRegistrationComplete(nr_ue_nas_t *nas, as_nas_info_t *initia
   for(int i = 0; i < 4; i++){
      initialNasMsg->data[2+i] = mac[i];
   }
+  /* Set NAS 5GMM state */
+  nas->fiveGMM_state = FGS_REGISTERED;
 }
 
 void decodeDownlinkNASTransport(as_nas_info_t *initialNasMsg, uint8_t * pdu_buffer){
@@ -776,6 +779,8 @@ static void generateDeregistrationRequest(nr_ue_nas_t *nas, as_nas_info_t *initi
 
   for(int i = 0; i < 4; i++)
     initialNasMsg->data[2 + i] = mac[i];
+  /* Set NAS 5GMM state */
+  nas->fiveGMM_state = FGS_DEREGISTERED_INITIATED;
 }
 
 static void generatePduSessionEstablishRequest(nr_ue_nas_t *nas, as_nas_info_t *initialNasMsg, nas_pdu_session_req_t *pdu_req)
@@ -1225,6 +1230,8 @@ void *nas_nrue(void *args_p)
             break;
           case FGS_DEREGISTRATION_ACCEPT:
             LOG_I(NAS, "received deregistration accept\n");
+            /* Set NAS 5GMM state */
+            nas->fiveGMM_state = FGS_DEREGISTERED;
             break;
           case FGS_PDU_SESSION_ESTABLISHMENT_ACC: {
             uint8_t offset = 0;

openair3/NAS/NR_UE/nr_nas_msg_sim.h

@@ -83,6 +83,14 @@ typedef struct {
   int hplmn_sd;
 } nr_nas_msg_snssai_t;
 
+typedef enum fgs_mm_state_e {
+  FGS_DEREGISTERED = 0,
+  FGS_DEREGISTERED_INITIATED,
+  FGS_REGISTERED_INITIATED,
+  FGS_REGISTERED,
+  FGS_SERVICE_REQUEST_INITIATED,
+} fgs_mm_state_t;
+
 /* Security Key for SA UE */
 typedef struct {
   uint8_t kausf[32];
@@ -97,6 +105,8 @@ typedef struct {
 } ue_sa_security_key_t;
 
 typedef struct {
+  /* 5GS Mobility Management States (5.1.3.2.1 of 3GPP TS 24.501) */
+  fgs_mm_state_t fiveGMM_state;
   uicc_t *uicc;
   ue_sa_security_key_t security;
   stream_security_container_t *security_container;