Handle both 5G-S-TMSI and GUAMI in the NGAP Initial UE Message procedures

* use bitmask to select presence of either 5G-S-TMSI or GUAMI
* select the AMF based on
  (1) absence of UE Identity (2) Presence of GUAMI (3) Presence of 5G-S-TMSI

Related to #801

openair2/COMMON/ngap_messages_types.h

@@ -217,7 +217,6 @@ typedef struct ngap_ue_paging_identity_s {
 } ngap_ue_paging_identity_t;
 
 typedef enum ngap_ue_identities_presenceMask_e {
-  NGAP_UE_IDENTITIES_NONE          = 0,
   NGAP_UE_IDENTITIES_FiveG_s_tmsi  = 1 << 1,
   NGAP_UE_IDENTITIES_guami         = 1 << 2,
 } ngap_ue_identities_presenceMask_t;

openair2/RRC/NR/rrc_gNB_NGAP.c

@@ -189,19 +189,20 @@ void rrc_gNB_send_NGAP_NAS_FIRST_REQ(gNB_RRC_INST *rrc, gNB_RRC_UE_t *UE, NR_RRC
 
   /* 5G-S-TMSI */
   if (UE->Initialue_identity_5g_s_TMSI.presence) {
-    // 5G-S-TMSI
+    req->ue_identity.presenceMask |= NGAP_UE_IDENTITIES_FiveG_s_tmsi;
-    req->ue_identity.presenceMask = NGAP_UE_IDENTITIES_FiveG_s_tmsi;
     req->ue_identity.s_tmsi.amf_set_id = UE->Initialue_identity_5g_s_TMSI.amf_set_id;
     req->ue_identity.s_tmsi.amf_pointer = UE->Initialue_identity_5g_s_TMSI.amf_pointer;
     req->ue_identity.s_tmsi.m_tmsi = UE->Initialue_identity_5g_s_TMSI.fiveg_tmsi;
-  } else if (rrcSetupComplete->registeredAMF != NULL) {
+  }
-    /**
+
-     * Fetch the AMF-Identifier from the registeredAMF IE
+  /* Process Registered AMF IE */
+  if (rrcSetupComplete->registeredAMF != NULL) {
+    /* Fetch the AMF-Identifier from the registeredAMF IE
      * The IE AMF-Identifier (AMFI) comprises of an AMF Region ID (8b),
      * an AMF Set ID (10b) and an AMF Pointer (6b)
      * as specified in TS 23.003 [21], clause 2.10.1. */
     NR_RegisteredAMF_t *r_amf = rrcSetupComplete->registeredAMF;
-    req->ue_identity.presenceMask = NGAP_UE_IDENTITIES_guami;
+    req->ue_identity.presenceMask |= NGAP_UE_IDENTITIES_guami;
     uint32_t amf_Id = BIT_STRING_to_uint32(&r_amf->amf_Identifier);
     UE->ue_guami = req->ue_identity.guami = get_guami(amf_Id);
     LOG_I(NGAP,
@@ -210,8 +211,6 @@ void rrc_gNB_send_NGAP_NAS_FIRST_REQ(gNB_RRC_INST *rrc, gNB_RRC_UE_t *UE, NR_RRC
           req->ue_identity.guami.amf_set_id,
           req->ue_identity.guami.amf_region_id,
           req->ue_identity.guami.amf_pointer);
-  } else {
-    req->ue_identity.presenceMask = NGAP_UE_IDENTITIES_NONE;
   }
 
   itti_send_msg_to_task(TASK_NGAP, rrc->module_id, message_p);

openair3/NGAP/ngap_gNB_nas_procedures.c

@@ -79,9 +79,15 @@ static ngap_gNB_amf_data_t *select_amf(ngap_gNB_instance_t *instance_p, const ng
 {
   ngap_gNB_amf_data_t *amf = NULL;
 
-  /* Select the AMF corresponding to the provided GUAMI. */
+  // Select the AMF corresponding to the GUAMI from the RegisteredAMF IE
   if (msg->ue_identity.presenceMask & NGAP_UE_IDENTITIES_guami) {
     const nr_guami_t *guami = &msg->ue_identity.guami;
+    NGAP_DEBUG("GUAMI is present: MCC=%03d MNC=%03d RegionID=%d SetID=%d Pointer=%d\n",
+               guami->mcc,
+               guami->mnc,
+               guami->amf_region_id,
+               guami->amf_set_id,
+               guami->amf_pointer);
     amf = ngap_gNB_nnsf_select_amf_by_guami(instance_p, msg->establishment_cause, *guami);
     if (amf) {
       NGAP_INFO("UE %d: Chose AMF '%s' (assoc_id %d) through GUAMI MCC %d MNC %d AMFRI %d AMFSI %d AMFPT %d\n",
@@ -93,12 +99,12 @@ static ngap_gNB_amf_data_t *select_amf(ngap_gNB_instance_t *instance_p, const ng
                 guami->amf_region_id,
                 guami->amf_set_id,
                 guami->amf_pointer);
+      return amf;
     }
   }
 
+  // Select the AMF corresponding to the provided 5G-S-TMSI
   if (amf == NULL) {
-    /* Select the AMF corresponding to the provided s-TMSI. */
-    //TODO have not be test. it's should be test
     if (msg->ue_identity.presenceMask & NGAP_UE_IDENTITIES_FiveG_s_tmsi) {
       const fiveg_s_tmsi_t *fgs_tmsi = &msg->ue_identity.s_tmsi;
       amf = ngap_gNB_nnsf_select_amf_by_amf_setid(instance_p, msg->establishment_cause, msg->selected_plmn_identity, fgs_tmsi->amf_set_id);
@@ -111,13 +117,14 @@ static ngap_gNB_amf_data_t *select_amf(ngap_gNB_instance_t *instance_p, const ng
                   msg->selected_plmn_identity,
                   instance_p->plmn[msg->selected_plmn_identity].plmn.mcc,
                   instance_p->plmn[msg->selected_plmn_identity].plmn.mnc);
+        return amf;
       }
     }
   }
 
-  if (amf == NULL) {
+  // No UE identity (5G-S-TMSI or GUAMI) is present
-    /* Select AMF based on the selected PLMN identity, received through RRC
+  if (msg->ue_identity.presenceMask == 0) {
-     * Connection Setup Complete */
+    // Select the AMF based on the selected PLMN identity received through RRCSetupComplete
     amf = ngap_gNB_nnsf_select_amf_by_plmn_id(instance_p, msg->establishment_cause, msg->selected_plmn_identity);
     if (amf) {
       NGAP_INFO("UE %d: Chose AMF '%s' (assoc_id %d) through selected PLMN Identity index %d MCC %d MNC %d\n",
@@ -127,17 +134,14 @@ static ngap_gNB_amf_data_t *select_amf(ngap_gNB_instance_t *instance_p, const ng
                 msg->selected_plmn_identity,
                 instance_p->plmn[msg->selected_plmn_identity].plmn.mcc,
                 instance_p->plmn[msg->selected_plmn_identity].plmn.mnc);
-    }
+      return amf;
-  }
+    } else {
-
+      // Select the AMF with the highest capacity
-  if (amf == NULL) {
+      amf = ngap_gNB_nnsf_select_amf(instance_p, msg->establishment_cause);
-    /*
+      if (amf) {
-     * If no AMF corresponds to the GUAMI, the s-TMSI, or the selected PLMN
+        NGAP_INFO("UE %d: Chose AMF '%s' (assoc_id %d) through highest relative capacity\n", msg->gNB_ue_ngap_id, amf->amf_name, amf->assoc_id);
-     * identity, selects the AMF with the highest capacity.
+        return amf;
-     */
+      }
-    amf = ngap_gNB_nnsf_select_amf(instance_p, msg->establishment_cause);
-    if (amf) {
-      NGAP_INFO("UE %d: Chose AMF '%s' (assoc_id %d) through highest relative capacity\n", msg->gNB_ue_ngap_id, amf->amf_name, amf->assoc_id);
     }
   }