Refactor tunnel endpoint struct members in pdu_session_t

Motivation:
Clarify the role of GTP tunnel endpoint IDs in PDU session handling. Previously,
the struct members (gNB_teid_N3, UPF_teid_N3, etc.) were confusingly named and
duplicated with separate transport-layer address fields.
This refactoring replaces these with explicit n3_incoming and n3_outgoing members using
gtpu_tunnel_t. This aligns with GTP conventions: "incoming TEID" refers to the
TEID received from the remote peer (UPF on N3), while "outgoing TEID" is the
TEID sent by the local entity (NG-RAN on N3) to the remote peer.

Benefits:
* Improves readability and clarity of the code
* Reduces redundant struct members, i.e. remove UPF_teid_N3, UPF_addr_N3
* Aligns naming with 3GPP conventions for transport layer tunnels

Changes:
* Replace gtp_addr_N3, gNB_teid_N3, gtp_teid, upf_addr with n3_incoming and n3_outgoing
* Update all related code to use the new struct members
* Aligns naming with 3GPP conventions for transport layer tunnels

openair2/COMMON/ngap_messages_types.h

@@ -249,15 +249,10 @@ typedef struct pdusession_s {
   pdusession_level_qos_parameter_t qos[QOSFLOW_MAX_VALUE];
   /* The transport layer address for the IP packets */
   pdu_session_type_t pdu_session_type;
-  transport_layer_addr_t upf_addr;
-  /* Outgoing (UL) NG-U Tunnel Endpoint Identifier (S-GW/UPF) */
-  uint32_t gtp_teid;
-  /* Incoming (DL) NG-U Tunnel Endpoint Identifier (S-GW/UPF) */
-  uint32_t gNB_teid_N3;
-  transport_layer_addr_t gNB_addr_N3;
-  /* Incoming (DL) NG-U Tunnel Endpoint Identifier (S-GW/UPF) */
-  uint32_t UPF_teid_N3;
-  transport_layer_addr_t UPF_addr_N3;
+  // NG-RAN endpoint of the NG-U (N3) transport bearer
+  gtpu_tunnel_t n3_outgoing;
+  // UPF endpoint of the NG-U (N3) transport bearer
+  gtpu_tunnel_t n3_incoming;
   nssai_t nssai;
 } pdusession_t;
 

openair2/E2AP/RAN_FUNCTION/CUSTOMIZED/ran_func_gtp.c

@@ -65,8 +65,8 @@ bool read_gtp_sm(void * data)
     int nb_pdu_session = ue_context_p->ue_context.nb_of_pdusessions;
     if (nb_pdu_session > 0) {
       int nb_pdu_idx = nb_pdu_session - 1;
-      gtp->msg.ngut[i].teidgnb = ue_context_p->ue_context.pduSession[nb_pdu_idx].param.gNB_teid_N3;
-      gtp->msg.ngut[i].teidupf = ue_context_p->ue_context.pduSession[nb_pdu_idx].param.UPF_teid_N3;
+      gtp->msg.ngut[i].teidgnb = ue_context_p->ue_context.pduSession[nb_pdu_idx].param.n3_outgoing.teid;
+      gtp->msg.ngut[i].teidupf = ue_context_p->ue_context.pduSession[nb_pdu_idx].param.n3_incoming.teid;
       // TODO: one PDU session has multiple QoS Flow
       int nb_qos_flow = ue_context_p->ue_context.pduSession[nb_pdu_idx].param.nb_qos;
       if (nb_qos_flow > 0) {

openair2/RRC/NR/rrc_gNB.c

@@ -2449,9 +2449,9 @@ void rrc_gNB_process_e1_bearer_context_setup_resp(e1ap_bearer_setup_resp_t *resp
       LOG_W(RRC, "E1: received setup for PDU session %ld, but has not been requested\n", e1_pdu->id);
       continue;
     }
-    rrc_pdu->param.gNB_teid_N3 = e1_pdu->tl_info.teId;
-    memcpy(&rrc_pdu->param.gNB_addr_N3.buffer, &e1_pdu->tl_info.tlAddress, sizeof(uint8_t) * 4);
-    rrc_pdu->param.gNB_addr_N3.length = sizeof(in_addr_t);
+    rrc_pdu->param.n3_outgoing.teid = e1_pdu->tl_info.teId;
+    memcpy(&rrc_pdu->param.n3_outgoing.addr.buffer, &e1_pdu->tl_info.tlAddress, sizeof(uint8_t) * 4);
+    rrc_pdu->param.n3_outgoing.addr.length = sizeof(in_addr_t);
 
     // save the tunnel address for the DRBs
     for (int i = 0; i < e1_pdu->numDRBSetup; i++) {

openair2/RRC/NR/rrc_gNB_NGAP.c

@@ -283,12 +283,11 @@ static int decodePDUSessionResourceSetup(pdusession_t *session)
         NGAP_GTPTunnel_t *gTPTunnel_p = pdusessionTransfer_ies->value.choice.UPTransportLayerInformation.choice.gTPTunnel;
 
         /* Set the transport layer address */
-        memcpy(session->upf_addr.buffer, gTPTunnel_p->transportLayerAddress.buf, gTPTunnel_p->transportLayerAddress.size);
-
-        session->upf_addr.length = gTPTunnel_p->transportLayerAddress.size * 8 - gTPTunnel_p->transportLayerAddress.bits_unused;
+        memcpy(session->n3_incoming.addr.buffer, gTPTunnel_p->transportLayerAddress.buf, gTPTunnel_p->transportLayerAddress.size);
+        session->n3_incoming.addr.length = gTPTunnel_p->transportLayerAddress.size * 8 - gTPTunnel_p->transportLayerAddress.bits_unused;
 
         /* GTP tunnel endpoint ID */
-        OCTET_STRING_TO_INT32(&gTPTunnel_p->gTP_TEID, session->gtp_teid);
+        OCTET_STRING_TO_INT32(&gTPTunnel_p->gTP_TEID, session->n3_incoming.teid);
       }
 
       break;
@@ -386,8 +385,8 @@ bool trigger_bearer_setup(gNB_RRC_INST *rrc, gNB_RRC_UE_t *UE, int n, pdusession
                                                                         : SECURITY_NOT_NEEDED;
     sec->confidentialityProtectionIndication = rrc->security.do_drb_ciphering ? SECURITY_REQUIRED
                                                                               : SECURITY_NOT_NEEDED;
-    pdu->UP_TL_information.teId = session->gtp_teid;
-    memcpy(&pdu->UP_TL_information.tlAddress, session->upf_addr.buffer, sizeof(in_addr_t));
+    pdu->UP_TL_information.teId = session->n3_incoming.teid;
+    memcpy(&pdu->UP_TL_information.tlAddress, session->n3_incoming.addr.buffer, sizeof(in_addr_t));
 
     /* we assume for the moment one DRB per PDU session. Activate the bearer,
      * and configure in RRC. */
@@ -582,9 +581,9 @@ void rrc_gNB_send_NGAP_INITIAL_CONTEXT_SETUP_RESP(gNB_RRC_INST *rrc, gNB_RRC_UE_
     if (session->status == PDU_SESSION_STATUS_DONE) {
       pdu_sessions_done++;
       resp->pdusessions[pdusession].pdusession_id = session->param.pdusession_id;
-      resp->pdusessions[pdusession].gtp_teid = session->param.gNB_teid_N3;
+      resp->pdusessions[pdusession].gtp_teid = session->param.n3_outgoing.teid;
       memcpy(resp->pdusessions[pdusession].gNB_addr.buffer,
-             session->param.gNB_addr_N3.buffer,
+             session->param.n3_outgoing.addr.buffer,
              sizeof(resp->pdusessions[pdusession].gNB_addr.buffer));
       resp->pdusessions[pdusession].gNB_addr.length = 4; // Fixme: IPv4 hard coded here
       resp->pdusessions[pdusession].nb_of_qos_flow = session->param.nb_qos;
@@ -777,10 +776,10 @@ void rrc_gNB_send_NGAP_PDUSESSION_SETUP_RESP(gNB_RRC_INST *rrc, gNB_RRC_UE_t *UE
       pdusession_setup_t *tmp = &resp->pdusessions[pdu_sessions_done];
       tmp->pdusession_id = session->param.pdusession_id;
       tmp->nb_of_qos_flow = session->param.nb_qos;
-      tmp->gtp_teid = session->param.gNB_teid_N3;
+      tmp->gtp_teid = session->param.n3_outgoing.teid;
       tmp->pdu_session_type = session->param.pdu_session_type;
-      tmp->gNB_addr.length = session->param.gNB_addr_N3.length;
-      memcpy(tmp->gNB_addr.buffer, session->param.gNB_addr_N3.buffer, tmp->gNB_addr.length);
+      tmp->gNB_addr.length = session->param.n3_outgoing.addr.length;
+      memcpy(tmp->gNB_addr.buffer, session->param.n3_outgoing.addr.buffer, tmp->gNB_addr.length);
       for (int qos_flow_index = 0; qos_flow_index < tmp->nb_of_qos_flow; qos_flow_index++) {
         tmp->associated_qos_flows[qos_flow_index].qfi = session->param.qos[qos_flow_index].qfi;
         tmp->associated_qos_flows[qos_flow_index].qos_flow_mapping_ind = QOSFLOW_MAPPING_INDICATION_DL;
@@ -1091,8 +1090,6 @@ int rrc_gNB_process_NGAP_PDUSESSION_MODIFY_REQ(MessageDef *msg_p, instance_t ins
       }
       // Save new pdu session parameters, qos, upf addr, teid
       decodePDUSessionResourceModify(&sess->param, UE->pduSession[i].param.pdusessionTransfer);
-      sess->param.UPF_addr_N3 = sessMod->upf_addr;
-      sess->param.UPF_teid_N3 = sessMod->gtp_teid;
     }
   }