From 98d922e56883a985dce4ac2fa8f77c20265de9d5 Mon Sep 17 00:00:00 2001
From: Guido Casati <hello@guidocasati.com>
Date: Mon, 20 May 2024 17:18:37 +0200
Subject: [PATCH] Introduced 5GMM state machine

* according to 5.1.3.2.1 of 3GPP TS 24.501
---
 openair3/NAS/NR_UE/nr_nas_msg.c |  8 ++++++++
 openair3/NAS/NR_UE/nr_nas_msg.h | 10 ++++++++++
 2 files changed, 18 insertions(+)

diff --git a/openair3/NAS/NR_UE/nr_nas_msg.c b/openair3/NAS/NR_UE/nr_nas_msg.c
index d7a1c42bf3..6166213fa9 100644
--- a/openair3/NAS/NR_UE/nr_nas_msg.c
+++ b/openair3/NAS/NR_UE/nr_nas_msg.c
@@ -505,6 +505,8 @@ void generateRegistrationRequest(as_nas_info_t *initialNasMsg, nr_ue_nas_t *nas)
 
   initialNasMsg->length = mm_msg_encode(&plain, initialNasMsg->nas_data, size);
   nas->registration_request_len = initialNasMsg->length;
+  /* set NAS 5GMM state */
+  nas->fiveGMM_state = FGS_REGISTERED_INITIATED;
 }
 
 void generateServiceRequest(as_nas_info_t *initialNasMsg, nr_ue_nas_t *nas)
@@ -812,6 +814,8 @@ static void generateRegistrationComplete(nr_ue_nas_t *nas,
   for (int i = 0; i < 4; i++) {
     initialNasMsg->nas_data[2 + i] = mac[i];
   }
+  /* Set NAS 5GMM state */
+  nas->fiveGMM_state = FGS_REGISTERED;
 }
 
 /**
@@ -1004,6 +1008,8 @@ static void generateDeregistrationRequest(nr_ue_nas_t *nas, as_nas_info_t *initi
   for (int i = 0; i < 4; i++) {
     initialNasMsg->nas_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)
@@ -1432,6 +1438,8 @@ void *nas_nrue(void *args_p)
             break;
           case FGS_DEREGISTRATION_ACCEPT_UE_ORIGINATING:
             LOG_I(NAS, "received deregistration accept\n");
+            /* Set NAS 5GMM state */
+            nas->fiveGMM_state = FGS_DEREGISTERED;
             break;
           case FGS_PDU_SESSION_ESTABLISHMENT_ACC:
             handle_pdu_session_accept(pdu_buffer, pdu_length);
diff --git a/openair3/NAS/NR_UE/nr_nas_msg.h b/openair3/NAS/NR_UE/nr_nas_msg.h
index b4a97a36d7..380da8cbbc 100644
--- a/openair3/NAS/NR_UE/nr_nas_msg.h
+++ b/openair3/NAS/NR_UE/nr_nas_msg.h
@@ -51,6 +51,14 @@
 /* 3GPP TS 24.501: 9.11.3.50 Service type */
 #define SERVICE_TYPE_DATA 0x1
 
+typedef enum fgs_mm_state_e {
+  FGS_DEREGISTERED,
+  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];
@@ -66,6 +74,8 @@ 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;