target-CU-CP: Add RRC handler NG DL RAN Status Transfer

openair2/RRC/NR/rrc_gNB.c

@@ -2854,6 +2854,10 @@ void *rrc_gnb_task(void *args_p) {
         rrc_gNB_process_NGAP_PDUSESSION_RELEASE_COMMAND(msg_p, instance);
         break;
 
+      case NGAP_DL_RAN_STATUS_TRANSFER:
+        rrc_gNB_process_NGAP_DL_RAN_STATUS_TRANSFER(msg_p, instance);
+        break;
+
       /* Messages from F1AP task */
       case F1AP_SETUP_REQ:
         AssertFatal(!NODE_IS_DU(RC.nrrrc[instance]->node_type), "should not receive F1AP_SETUP_REQUEST in DU!\n");

openair2/RRC/NR/rrc_gNB_NGAP.c

@@ -1605,3 +1605,51 @@ void rrc_gNB_send_NGAP_HANDOVER_REQUIRED(gNB_RRC_INST *rrc,
   NGAP_HANDOVER_REQUIRED(msg_p) = msg;
   itti_send_msg_to_task(TASK_NGAP, rrc->module_id, msg_p);
 }
+
+int rrc_gNB_process_NGAP_DL_RAN_STATUS_TRANSFER(MessageDef *msg_p, instance_t instance)
+{
+  const ngap_ran_status_transfer_t *cmd = &NGAP_DL_RAN_STATUS_TRANSFER(msg_p);
+  gNB_RRC_INST *rrc = RC.nrrrc[instance];
+  rrc_gNB_ue_context_t *ue_context_p = rrc_gNB_get_ue_context(rrc, cmd->gnb_ue_ngap_id);
+
+  if (!ue_context_p) {
+    LOG_E(NR_RRC, "[gNB %ld] No UE context for gNB_ue_ngap_id %u\n", instance, cmd->gnb_ue_ngap_id);
+    return -1;
+  }
+
+  gNB_RRC_UE_t *UE = &ue_context_p->ue_context;
+  LOG_I(NR_RRC,
+        "[gNB %ld] DL RAN Status Transfer for gNB_ue_ngap_id %u AMF_UE_NGAP_ID %lu\n",
+        instance,
+        cmd->gnb_ue_ngap_id,
+        cmd->amf_ue_ngap_id);
+
+  for (int i = 0; i < cmd->ran_status.nb_drb; ++i) {
+    const ngap_drb_status_t *s = &cmd->ran_status.drb_status_list[i];
+    LOG_I(NR_RRC,
+          "DL RAN Status Transfer - DRB ID %d:\n"
+          "  UL COUNT: PDCP SN = %u, HFN = %u (%s)\n"
+          "  DL COUNT: PDCP SN = %u, HFN = %u (%s)\n",
+          s->drb_id,
+          s->ul_count.pdcp_sn,
+          s->ul_count.hfn,
+          s->ul_count.sn_len == NGAP_SN_LENGTH_18 ? "18-bit" : "12-bit",
+          s->dl_count.pdcp_sn,
+          s->dl_count.hfn,
+          s->dl_count.sn_len == NGAP_SN_LENGTH_18 ? "18-bit" : "12-bit");
+
+    // Send to PDCP layer
+    for (int j = 0; j < MAX_DRBS_PER_UE; j++) {
+      if (UE->established_drbs[j].drb_id == s->drb_id)
+        nr_pdcp_update_ran_status(UE->rrc_ue_id,
+                                  s->drb_id,
+                                  s->ul_count.pdcp_sn,
+                                  s->ul_count.hfn,
+                                  s->dl_count.pdcp_sn,
+                                  s->dl_count.hfn,
+                                  s->dl_count.sn_len == NGAP_SN_LENGTH_18);
+    }
+  }
+
+  return 0;
+}

openair2/RRC/NR/rrc_gNB_NGAP.h

@@ -108,4 +108,6 @@ void rrc_gNB_send_NGAP_HANDOVER_NOTIFY(gNB_RRC_INST *rrc, gNB_RRC_UE_t *UE);
 
 int rrc_gNB_send_NGAP_ul_ran_status_transfer(gNB_RRC_INST *rrc, gNB_RRC_UE_t *UE, const int n_to_mod, const e1_pdcp_status_info_t *pdcp_status);
 
+int rrc_gNB_process_NGAP_DL_RAN_STATUS_TRANSFER(MessageDef *msg_p, instance_t instance);
+
 #endif