Merge remote-tracking branch 'origin/nas-issue-881' into integration_2025_w07 (!3176)

Refactor and extend NAS Registration Request

Extended NAS Registration Request generation and encoding according to
8.2.6 of 3GPP TS 24.501. Main topics:

- NAS Registration Type
- NAS KSI
- integrity protection
- NAS container encoding

Improvements:

- Add 5GMM Modes in NAS
- Introduced 5GMM state machine

Fixes:

- add 5GMM Capability IE to Registration Request
- closes #881, #819

openair2/RRC/NR_UE/rrc_UE.c

@@ -1106,7 +1106,8 @@ static void rrc_ue_generate_RRCSetupComplete(const NR_UE_RRC_INST_t *rrc, const
   if (IS_SA_MODE(get_softmodem_params())) {
     as_nas_info_t initialNasMsg;
     nr_ue_nas_t *nas = get_ue_nas_info(rrc->ue_id);
-    generateRegistrationRequest(&initialNasMsg, nas);
+    // Send Initial NAS message (Registration Request) before Security Mode control procedure
+    generateRegistrationRequest(&initialNasMsg, nas, false);
     nas_msg = (char *)initialNasMsg.nas_data;
     nas_msg_length = initialNasMsg.length;
   } else {

openair3/NAS/NR_UE/5GS/5GMM/IES/FGMMCapability.c

@@ -35,16 +35,55 @@
 #include "TLVDecoder.h"
 #include "FGMMCapability.h"
 
-int encode_5gmm_capability(const FGMMCapability *fgmmcapability, uint8_t iei, uint8_t *buffer, uint32_t len)
+#define MIN_LENGTH_5GMM_CAPABILITY 3
+
+/**
+ * @brief Encode 5GMM Capability IE (9.11.3 of 3GPP TS 24.501)
+ */
+int encode_5gmm_capability(uint8_t *buffer, const FGMMCapability *fgmmcapability, uint32_t len)
 {
   int encoded = 0;
-  if (iei) {
+
+  // Ensure buffer length is sufficient
+  if (len < MIN_LENGTH_5GMM_CAPABILITY) {
+    printf("Buffer length insufficient for encoding 5GMM capability\n");
+    return -1;
+  }
+
+  if (fgmmcapability->iei) {
     *buffer = fgmmcapability->iei;
     encoded++;
-    *(buffer + encoded) = fgmmcapability->length;
+  } else {
+    printf("Missing IEI in fgmmcapability\n");
+  }
+
+  buffer[encoded] = fgmmcapability->length;
+  encoded++;
+
+  // Encode octet 3 (mandatory)
+  buffer[encoded] = (fgmmcapability->sgc << 7) | (fgmmcapability->iphc_cp_cIoT << 6) | (fgmmcapability->n3_data << 5)
+                    | (fgmmcapability->cp_cIoT << 4) | (fgmmcapability->restrict_ec << 3) | (fgmmcapability->lpp << 2)
+                    | (fgmmcapability->ho_attach << 1) | fgmmcapability->s1_mode;
+  encoded++;
+
+  // Encode octet 4
+  if (fgmmcapability->length >= 2) {
+    buffer[encoded] = (fgmmcapability->racs << 7) | (fgmmcapability->nssaa << 6) | (fgmmcapability->lcs << 5)
+                      | (fgmmcapability->v2x_cnpc5 << 4) | (fgmmcapability->v2x_cepc5 << 3) | (fgmmcapability->v2x << 2)
+                      | (fgmmcapability->up_cIoT << 1) | fgmmcapability->srvcc;
     encoded++;
-    *(buffer + encoded) = fgmmcapability->value;
+  }
+
+  // Encode octet 5
+  if (fgmmcapability->length >= 3) {
+    buffer[encoded] = (fgmmcapability->ehc_CP_ciot << 3) | (fgmmcapability->multiple_eUP << 2) | (fgmmcapability->wusa << 1)
+                      | fgmmcapability->cag;
     encoded++;
   }
+
+  // Encode octets 6 - 15
+  if (fgmmcapability->length >= 4)
+    memset(&buffer[encoded], 0, fgmmcapability->length - 3);
+
   return encoded;
 }

openair3/NAS/NR_UE/5GS/5GMM/IES/FGMMCapability.h

@@ -30,6 +30,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <stdbool.h>
 
 #include "OctetString.h"
 
@@ -39,9 +40,28 @@
 typedef struct {
   uint8_t iei;
   uint8_t length;
-  uint8_t value;
+  bool sgc;
+  bool iphc_cp_cIoT;
+  bool n3_data;
+  bool cp_cIoT;
+  bool restrict_ec;
+  bool lpp;
+  bool ho_attach;
+  bool s1_mode;
+  bool racs;
+  bool nssaa;
+  bool lcs;
+  bool v2x_cnpc5;
+  bool v2x_cepc5;
+  bool v2x;
+  bool up_cIoT;
+  bool srvcc;
+  bool ehc_CP_ciot;
+  bool multiple_eUP;
+  bool wusa;
+  bool cag;
 } FGMMCapability;
 
-int encode_5gmm_capability(const FGMMCapability *fgmmcapability, uint8_t iei, uint8_t *buffer, uint32_t len);
+int encode_5gmm_capability(uint8_t *buffer, const FGMMCapability *fgmmcapability, uint32_t len);
 
 #endif /* FGMM_CAPABILITY_H_ */

openair3/NAS/NR_UE/5GS/5GMM/IES/FGSRegistrationType.c

@@ -30,11 +30,14 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
-
+#include <stdbool.h>
 #include "TLVEncoder.h"
 #include "TLVDecoder.h"
 #include "FGSRegistrationType.h"
 
+#define NO_FOLLOW_ON_REQUEST 0x0
+#define FOLLOW_ON_REQUEST 0x08
+
 int decode_5gs_registration_type(FGSRegistrationType *fgsregistrationtype, uint8_t iei, uint8_t value, uint32_t len)
 {
   int decoded = 0;
@@ -49,14 +52,14 @@ int decode_5gs_registration_type(FGSRegistrationType *fgsregistrationtype, uint8
   return decoded;
 }
 
-int encode_5gs_registration_type(const FGSRegistrationType *fgsregistrationtype)
+/**
+ * @brief Encode 5GS registration type (9.11.3.7 of 3GPP TS 24.501)
+ *        Note: mandatory IE (IEI = 0)
+ */
+int encode_5gs_registration_type(const FGSRegistrationType *fgsregistrationtype, bool follow_on_request)
 {
-  uint8_t bufferReturn;
-  uint8_t *buffer = &bufferReturn;
-  uint8_t encoded = 0;
-  uint8_t iei = 0;
-  *(buffer + encoded) = 0x00 | (iei & 0xf0) | 0x8 | (*fgsregistrationtype & 0x7);
-  encoded++;
-
-  return bufferReturn;
+  // Follow-on request bit
+  uint8_t foR = follow_on_request ? FOLLOW_ON_REQUEST : NO_FOLLOW_ON_REQUEST;
+  // Return encoded value
+  return (foR | (*fgsregistrationtype & 0x7));
 }

openair3/NAS/NR_UE/5GS/5GMM/IES/FGSRegistrationType.h

@@ -29,7 +29,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
-
+#include <stdbool.h>
 #include "OctetString.h"
 
 #ifndef FGS_REGISTRATION_TYPE_H_
@@ -41,13 +41,15 @@
 typedef uint8_t FGSRegistrationType;
 
 // clang-format off
+/* 3GPP TS 24.501 Table 9.11.3.7.1: 5GS registration type IE */
 #define INITIAL_REGISTRATION               0b001
 #define MOBILITY_REGISTRATION_UPDATING     0b010
 #define PERIODIC_REGISTRATION_UPDATING     0b011
 #define EMERGENCY_REGISTRATION             0b100
+#define REG_TYPE_RESERVED                  0b111
 // clang-format on
 
-int encode_5gs_registration_type(const FGSRegistrationType *fgsregistrationtype);
+int encode_5gs_registration_type(const FGSRegistrationType *fgsregistrationtype, bool follow_on_request);
 
 int decode_5gs_registration_type(FGSRegistrationType *fgsregistrationtype, uint8_t iei, uint8_t value, uint32_t len);
 

openair3/NAS/NR_UE/5GS/5GMM/MSG/RegistrationRequest.c

@@ -72,9 +72,10 @@ int encode_registration_request(const registration_request_msg *registration_req
 {
   int encoded = 0;
   int encode_result = 0;
+  bool is_for = true; // Follow-on request pending
 
   *(buffer + encoded) = ((encode_nas_key_set_identifier(&registration_request->naskeysetidentifier, IEI_NULL) & 0x0f) << 4)
-                        | (encode_5gs_registration_type(&registration_request->fgsregistrationtype) & 0x0f);
+                        | (encode_5gs_registration_type(&registration_request->fgsregistrationtype, is_for) & 0x0f);
   encoded++;
 
   if ((encode_result = encode_5gs_mobile_identity(&registration_request->fgsmobileidentity, 0, buffer + encoded, len - encoded))
@@ -86,12 +87,7 @@ int encode_registration_request(const registration_request_msg *registration_req
 
   if ((registration_request->presencemask & REGISTRATION_REQUEST_5GMM_CAPABILITY_PRESENT)
       == REGISTRATION_REQUEST_5GMM_CAPABILITY_PRESENT) {
-    if ((encode_result = encode_5gmm_capability(&registration_request->fgmmcapability,
-                                                REGISTRATION_REQUEST_5GMM_CAPABILITY_IEI,
-                                                buffer + encoded,
-                                                len - encoded))
-        < 0)
-      // Return in case of error
+    if ((encode_result = encode_5gmm_capability(buffer + encoded, &registration_request->fgmmcapability, len - encoded)) < 0)
       return encode_result;
     else
       encoded += encode_result;

openair3/NAS/NR_UE/5GS/5GMM/MSG/RegistrationRequest.h

@@ -35,6 +35,7 @@
 #include "NasKeySetIdentifier.h"
 #include "NrUESecurityCapability.h"
 #include "SecurityHeaderType.h"
+#include "FGCNasMessageContainer.h"
 
 #ifndef REGISTRATION_REQUEST_H_
 #define REGISTRATION_REQUEST_H_
@@ -102,6 +103,7 @@ typedef struct registration_request_msg_tag {
   NasKeySetIdentifier naskeysetidentifier;
   FGSMobileIdentity fgsmobileidentity;
   /* Optional fields */
+  FGCNasMessageContainer fgsnasmessagecontainer;
   uint32_t presencemask;
   FGMMCapability fgmmcapability;
   NrUESecurityCapability nruesecuritycapability;

openair3/NAS/NR_UE/nr_nas_msg.h

@@ -51,6 +51,24 @@
 /* 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;
+
+/*
+ * 5GS mobility management (5GMM) modes
+ * 5.1.3.2.1.1 of TS 24.501
+ */
+typedef enum fgs_mm_mode_e {
+  FGS_NOT_CONNECTED,
+  FGS_IDLE,
+  FGS_CONNECTED,
+} fgs_mm_mode_t;
+
 /* Security Key for SA UE */
 typedef struct {
   uint8_t kausf[32];
@@ -66,18 +84,24 @@ 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;
+  /* 5GS Mobility Management mode */
+  fgs_mm_mode_t fiveGMM_mode;
   uicc_t *uicc;
   ue_sa_security_key_t security;
   stream_security_container_t *security_container;
   Guti5GSMobileIdentity_t *guti;
   bool termination_procedure;
-  uint8_t *registration_request_buf;
-  uint32_t registration_request_len;
   instance_t UE_id;
+  /* RRC Inactive Indication */
+  bool is_rrc_inactive;
+  /* Timer T3512 */
+  int t3512;
 } nr_ue_nas_t;
 
 nr_ue_nas_t *get_ue_nas_info(module_id_t module_id);
-void generateRegistrationRequest(as_nas_info_t *initialNasMsg, nr_ue_nas_t *nas);
+void generateRegistrationRequest(as_nas_info_t *initialNasMsg, nr_ue_nas_t *nas, bool is_security_mode);
 void generateServiceRequest(as_nas_info_t *initialNasMsg, nr_ue_nas_t *nas);
 void *nas_nrue_task(void *args_p);
 void *nas_nrue(void *args_p);