cu_cp,ngap: move ue creation to cu-cp

lib/cu_cp/adapters/ngap_adapters.h

@@ -32,12 +32,6 @@ class ngap_cu_cp_adapter : public ngap_cu_cp_du_repository_notifier, public ngap
     cu_cp_handler         = &cu_cp_handler_;
   }
 
-  ue_index_t request_new_ue_index_allocation(nr_cell_global_id_t cgi) override
-  {
-    srsran_assert(du_repository_handler != nullptr, "CU-CP Paging handler must not be nullptr");
-    return du_repository_handler->handle_ue_index_allocation_request(cgi);
-  }
-
   void on_paging_message(cu_cp_paging_message& msg) override
   {
     srsran_assert(du_repository_handler != nullptr, "CU-CP Paging handler must not be nullptr");
@@ -103,6 +97,12 @@ class ngap_cu_cp_adapter : public ngap_cu_cp_du_repository_notifier, public ngap
     return cu_cp_handler->handle_new_handover_command(ue_index, std::move(command));
   }
 
+  ue_index_t request_new_ue_index_allocation(nr_cell_global_id_t cgi) override
+  {
+    srsran_assert(cu_cp_handler != nullptr, "CU-CP NGAP handler must not be nullptr");
+    return cu_cp_handler->handle_ue_index_allocation_request(cgi);
+  }
+
   void on_n2_disconnection() override
   {
     srsran_assert(cu_cp_handler != nullptr, "CU-CP NGAP handler must not be nullptr");

lib/cu_cp/cu_cp_impl.cpp

@@ -497,6 +497,16 @@ async_task<bool> cu_cp_impl::handle_new_handover_command(ue_index_t ue_index, by
   });
 }
 
+ue_index_t cu_cp_impl::handle_ue_index_allocation_request(const nr_cell_global_id_t& cgi)
+{
+  du_index_t du_index = du_db.find_du(cgi);
+  if (du_index == du_index_t::invalid) {
+    logger.warning("Could not find DU for CGI={}", cgi.nci);
+    return ue_index_t::invalid;
+  }
+  return ue_mng.add_ue(du_index);
+}
+
 void cu_cp_impl::handle_n2_disconnection()
 {
   // TODO

lib/cu_cp/cu_cp_impl.h

@@ -81,6 +81,7 @@ class cu_cp_impl final : public cu_cp,
   async_task<ngap_handover_resource_allocation_response>
                    handle_ngap_handover_request(const ngap_handover_request& request) override;
   async_task<bool> handle_new_handover_command(ue_index_t ue_index, byte_buffer command) override;
+  ue_index_t       handle_ue_index_allocation_request(const nr_cell_global_id_t& cgi) override;
   void             handle_n2_disconnection() override;
 
   // cu_cp_measurement_handler

lib/cu_cp/cu_cp_impl_interface.h

@@ -93,6 +93,9 @@ class cu_cp_ngap_handler : public cu_cp_ue_context_release_handler, public cu_cp
   /// \returns True if the Handover Command was successfully handled, false otherwise.
   virtual async_task<bool> handle_new_handover_command(ue_index_t ue_index, byte_buffer command) = 0;
 
+  /// \brief Handles UE index allocation request for N2 handover at target gNB
+  virtual ue_index_t handle_ue_index_allocation_request(const nr_cell_global_id_t& cgi) = 0;
+
   /// \brief Handle N2 AMF connection drop.
   virtual void handle_n2_disconnection() = 0;
 };

lib/cu_cp/du_processor/du_processor.h

@@ -290,9 +290,6 @@ class du_repository_ngap_handler
 
   /// \brief Handles a Paging message notification.
   virtual void handle_paging_message(cu_cp_paging_message& msg) = 0;
-
-  /// \brief Handles UE index allocation request for N2 handover at target gNB
-  virtual ue_index_t handle_ue_index_allocation_request(const nr_cell_global_id_t& cgi) = 0;
 };
 
 /// Methods to get statistics of the DU processor.

lib/cu_cp/du_processor/du_processor_repository.cpp

@@ -114,8 +114,21 @@ du_index_t du_processor_repository::find_du(pci_t pci)
 {
   du_index_t index = du_index_t::invalid;
   for (const auto& du : du_db) {
-    if (du.second.processor->has_cell(pci))
+    if (du.second.processor->has_cell(pci)) {
       return du.first;
+    }
+  }
+
+  return index;
+}
+
+du_index_t du_processor_repository::find_du(const nr_cell_global_id_t& cgi)
+{
+  du_index_t index = du_index_t::invalid;
+  for (const auto& du : du_db) {
+    if (du.second.processor->has_cell(cgi)) {
+      return du.first;
+    }
   }
 
   return index;
@@ -136,17 +149,6 @@ void du_processor_repository::handle_paging_message(cu_cp_paging_message& msg)
   }
 }
 
-ue_index_t du_processor_repository::handle_ue_index_allocation_request(const nr_cell_global_id_t& cgi)
-{
-  for (auto& du : du_db) {
-    if (du.second.processor->has_cell(cgi)) {
-      return cfg.ue_mng.add_ue(du.first);
-    }
-  }
-  logger.debug("No DU with plmn={} and cell_id={} found.", cgi.plmn_id, cgi.nci);
-  return ue_index_t::invalid;
-}
-
 std::vector<metrics_report::du_info> du_processor_repository::handle_du_metrics_report_request() const
 {
   std::vector<metrics_report::du_info> du_reports;

lib/cu_cp/du_processor/du_processor_repository.h

@@ -48,15 +48,19 @@ class du_processor_repository : public du_repository_ngap_handler, public du_rep
   explicit du_processor_repository(du_repository_config cfg_);
 
   /// \brief Checks whether a cell with the specified PCI is served by any of the connected DUs.
-  /// \param[out] The index of the DU serving the given PCI.
+  /// \param[in] pci The serving cell PCI.
+  /// \return The index of the DU serving the given PCI.
   du_index_t find_du(pci_t pci);
 
+  /// \brief Checks whether a cell with the specified CGI is served by any of the connected DUs.
+  /// \param[in] cgi The serving cell CGI.
+  /// \return The index of the DU serving the given CGI.
+  du_index_t find_du(const nr_cell_global_id_t& cgi);
+
   du_processor& get_du_processor(du_index_t du_index);
 
   void handle_paging_message(cu_cp_paging_message& msg) override;
 
-  ue_index_t handle_ue_index_allocation_request(const nr_cell_global_id_t& nci) override;
-
   std::vector<metrics_report::du_info> handle_du_metrics_report_request() const override;
 
   size_t get_nof_f1ap_ues();