cu_cp: make RNTI optional when creating UE context

Author: andrepuschmann

include/srsran/cu_cp/ue_manager.h

@@ -101,7 +101,7 @@ class du_processor_ue_manager : public common_ue_manager
   /// \param[in] pci PCI of the cell that the UE is connected to.
   /// \param[in] rnti RNTI of the UE to be added.
   /// \return Pointer to the newly added DU UE if successful, nullptr otherwise.
-  virtual du_ue* add_ue(du_index_t du_index, pci_t pci, rnti_t rnti) = 0;
+  virtual du_ue* add_ue(du_index_t du_index, pci_t pci, optional<rnti_t> rnti) = 0;
 
   /// \brief Remove the DU UE context with the given UE index.
   /// \param[in] ue_index Index of the UE to be removed.

lib/cu_cp/ue_manager_impl.cpp

@@ -36,24 +36,27 @@ du_ue* ue_manager::find_du_ue(ue_index_t ue_index)
   return nullptr;
 }
 
-du_ue* ue_manager::add_ue(du_index_t du_index, pci_t pci, rnti_t rnti)
+du_ue* ue_manager::add_ue(du_index_t du_index, pci_t pci, optional<rnti_t> rnti)
 {
   // check if PCI is valid
   if (pci == INVALID_PCI) {
     logger.error("Invalid pci={}.", pci);
     return nullptr;
   }
 
-  // check if RNTI is valid
-  if (rnti == INVALID_RNTI) {
-    logger.error("Invalid rnti={}.", rnti);
-    return nullptr;
-  }
+  // if the RNTI is provided it needs to be valid and it must not be already present.
+  if (rnti.has_value()) {
+    // check if RNTI is valid
+    if (rnti.value() == INVALID_RNTI) {
+      logger.error("Invalid rnti={}.", rnti);
+      return nullptr;
+    }
 
-  // check if the UE is already present
-  if (get_ue_index(pci, rnti) != ue_index_t::invalid) {
-    logger.error("UE with pci={} and rnti={} already exists.", pci, rnti);
-    return nullptr;
+    // check if the UE is already present
+    if (get_ue_index(pci, rnti.value()) != ue_index_t::invalid) {
+      logger.error("UE with pci={} and rnti={} already exists.", pci, rnti.value());
+      return nullptr;
+    }
   }
 
   ue_index_t new_ue_index = get_next_ue_index(du_index);
@@ -66,8 +69,10 @@ du_ue* ue_manager::add_ue(du_index_t du_index, pci_t pci, rnti_t rnti)
   ues.emplace(
       std::piecewise_construct, std::forward_as_tuple(new_ue_index), std::forward_as_tuple(new_ue_index, pci, rnti));
 
-  // Add RNTI to lookup
-  pci_rnti_to_ue_index.emplace(std::make_tuple(pci, rnti), new_ue_index);
+  // Add RNTI to lookup if it was provided.
+  if (rnti.has_value()) {
+    pci_rnti_to_ue_index.emplace(std::make_tuple(pci, rnti.value()), new_ue_index);
+  }
 
   auto& ue         = ues.at(new_ue_index);
   ue.du_ue_created = true;

lib/cu_cp/ue_manager_impl.h

@@ -26,7 +26,7 @@ struct ngap_ue_context_t {
 class cu_cp_ue : public du_ue, public ngap_ue
 {
 public:
-  cu_cp_ue(const ue_index_t ue_index_, const pci_t pci_, const rnti_t c_rnti_) :
+  cu_cp_ue(const ue_index_t ue_index_, const pci_t pci_, const optional<rnti_t> c_rnti_) :
     ue_index(ue_index_), pci(pci_), c_rnti(c_rnti_)
   {
     du_index = get_du_index_from_ue_index(ue_index);
@@ -52,7 +52,13 @@ class cu_cp_ue : public du_ue, public ngap_ue
   pci_t get_pci() override { return pci; };
 
   /// \brief Get the C-RNTI of the UE.
-  rnti_t get_c_rnti() override { return c_rnti; }
+  rnti_t get_c_rnti() override
+  {
+    if (c_rnti.has_value()) {
+      return c_rnti.value();
+    }
+    return rnti_t::INVALID_RNTI;
+  }
 
   /// \brief Get the DU index of the UE.
   du_index_t get_du_index() override { return du_index; }
@@ -149,10 +155,10 @@ class cu_cp_ue : public du_ue, public ngap_ue
   ue_index_t ue_index = ue_index_t::invalid;
 
   // du ue context
-  du_index_t      du_index    = du_index_t::invalid;
-  du_cell_index_t pcell_index = du_cell_index_t::invalid;
-  pci_t           pci         = INVALID_PCI;
-  rnti_t          c_rnti      = INVALID_RNTI;
+  du_index_t       du_index    = du_index_t::invalid;
+  du_cell_index_t  pcell_index = du_cell_index_t::invalid;
+  pci_t            pci         = INVALID_PCI;
+  optional<rnti_t> c_rnti;
 
   std::map<srb_id_t, cu_srb_context>            srbs;
   rrc_ue_task_scheduler*                        task_sched      = nullptr;
@@ -191,7 +197,7 @@ class ue_manager : public du_processor_ue_manager, public ngap_ue_manager
   /// \param[in] pci PCI of the cell that the UE is connected to.
   /// \param[in] rnti RNTI of the UE to be added.
   /// \return Pointer to the newly added DU UE if successful, nullptr otherwise.
-  du_ue* add_ue(du_index_t du_index, pci_t pci, rnti_t rnti) override;
+  du_ue* add_ue(du_index_t du_index, pci_t pci, optional<rnti_t> rnti) override;
 
   /// \brief Remove the DU UE context with the given UE index.
   /// \param[in] ue_index Index of the UE to be removed.