nr,gnb,rrc: correctly release NR RNTI user after Reestablishment

srsenb/hdr/stack/rrc/rrc_endc.h

@@ -126,11 +126,13 @@ private:
   struct endc_disabled_st {};          // EN-DC disabled
 
   // FSM guards
+  bool requires_rel_req(const sgnb_rel_req_ev& ev);
+  bool skip_rel_req(const sgnb_rel_req_ev& ev);
 
   // FSM transition handlers
   void handle_sgnb_add_req_ack(wait_sgnb_add_req_resp_st& s, const sgnb_add_req_ack_ev& ev);
-  void handle_sgnb_rel_req(endc_activated_st& s, const sgnb_rel_req_ev& ev);
-  void handle_rrc_reest(const rrc_reest_rx_ev& ev);
+  void handle_sgnb_rel_req(const sgnb_rel_req_ev& ev);
+  void handle_rrc_reest(endc_activated_st& s, const rrc_reest_rx_ev& ev);
   void handle_endc_disabled(const disable_endc_ev& ev);
 
 protected:
@@ -163,9 +165,10 @@ protected:
   row< wait_sgnb_add_req_resp_st, endc_deactivated_st,       sgnb_add_req_reject_ev                                                          >,
   row< prepare_recfg_st,          wait_add_complete_st,      rrc_recfg_sent_ev                                                               >,
   row< wait_add_complete_st,      endc_activated_st,         sgnb_add_complete_ev                                                            >,
+  upd< endc_activated_st,                                    rrc_reest_rx_ev,         &fsm::handle_rrc_reest                                 >,
   // +---------------------------+--------------------------+------------------------+------------------------------+-------------------------+
-  row< endc_activated_st,         wait_sgnb_rel_req_resp_st, sgnb_rel_req_ev,         &fsm::handle_sgnb_rel_req                             >,
-  to_state<                       endc_deactivated_st,       rrc_reest_rx_ev,         &fsm::handle_rrc_reest                                >,
+  to_state<                       wait_sgnb_rel_req_resp_st, sgnb_rel_req_ev,         &fsm::handle_sgnb_rel_req,      &fsm::requires_rel_req >,
+  to_state<                       endc_deactivated_st,       sgnb_rel_req_ev,         &fsm::handle_sgnb_rel_req,      &fsm::skip_rel_req     >,
   row< wait_sgnb_rel_req_resp_st, endc_deactivated_st,       sgnb_rel_req_ack_ev                                                             >,
   to_state<                       endc_disabled_st,          disable_endc_ev,         &fsm::handle_endc_disabled                             >
   >;

srsenb/src/stack/rrc/rrc.cc

@@ -569,7 +569,7 @@ void rrc::set_erab_status(uint16_t rnti, const asn1::s1ap::bearers_subject_to_st
 
 void rrc::sgnb_addition_ack(uint16_t eutra_rnti, sgnb_addition_ack_params_t params)
 {
-  logger.info("Received SgNB addition acknowledgement for rnti=%d", eutra_rnti);
+  logger.info("Received SgNB addition acknowledgement for rnti=0x%x", eutra_rnti);
   auto ue_it = users.find(eutra_rnti);
   if (ue_it == users.end()) {
     logger.warning("rnti=0x%x does not exist", eutra_rnti);

srsenb/src/stack/rrc/rrc_endc.cc

@@ -312,7 +312,7 @@ void rrc::ue::rrc_endc::start_sgnb_addition()
   rrc_nr_interface_rrc::sgnb_addition_req_params_t params = {};
   params.eps_bearer_id =
       rrc_enb->bearer_manager.get_lcid_bearer(rrc_ue->rnti, drb_to_lcid((lte_drb)eutra_drb_id)).eps_bearer_id;
-  logger.info("Triggering SgNB addition");
+  logger.info("Triggering SgNB addition for E-UTRA rnti=0x%x", rrc_ue->rnti);
   rrc_enb->rrc_nr->sgnb_addition_request(rrc_ue->rnti, params);
 
   sgnb_add_req_sent_ev sgnb_add_req{};
@@ -358,9 +358,10 @@ void rrc::ue::rrc_endc::handle_sgnb_add_req_ack(wait_sgnb_add_req_resp_st& s, co
   nr_rnti = ev.params.nr_rnti;
 }
 
-void rrc::ue::rrc_endc::handle_sgnb_rel_req(endc_activated_st& s, const sgnb_rel_req_ev& ev)
+void rrc::ue::rrc_endc::handle_sgnb_rel_req(const sgnb_rel_req_ev& ev)
 {
-  logger.info("Triggering SgNB release");
+  logger.info("Triggering SgNB release for E-UTRA rnti=0x%x", rrc_ue->rnti);
+  rrc_enb->bearer_manager.rem_user(nr_rnti);
   rrc_enb->rrc_nr->sgnb_release_request(nr_rnti);
 }
 
@@ -369,14 +370,10 @@ bool rrc::ue::rrc_endc::is_endc_supported()
   return not is_in_state<endc_disabled_st>();
 }
 
-void rrc::ue::rrc_endc::handle_rrc_reest(const rrc_reest_rx_ev& ev)
+void rrc::ue::rrc_endc::handle_rrc_reest(endc_activated_st& s, const rrc_reest_rx_ev& ev)
 {
-  auto& sgnb_config = get_state<prepare_recfg_st>()->sgnb_config;
-
   // Transition GTPU tunnel rnti back from NR RNTI to LTE RNTI, given that the reconfiguration failed
-  rrc_enb->gtpu->mod_bearer_rnti(sgnb_config.nr_rnti, rrc_ue->rnti);
-
-  rrc_enb->bearer_manager.rem_user(sgnb_config.nr_rnti);
+  rrc_enb->gtpu->mod_bearer_rnti(nr_rnti, rrc_ue->rnti);
 }
 
 void rrc::ue::rrc_endc::handle_endc_disabled(const disable_endc_ev& ev)
@@ -384,4 +381,14 @@ void rrc::ue::rrc_endc::handle_endc_disabled(const disable_endc_ev& ev)
   logger.info("Disabling NR EN-DC support for rnti=0x%x", nr_rnti);
 }
 
+bool rrc::ue::rrc_endc::requires_rel_req(const sgnb_rel_req_ev& ev)
+{
+  return not is_in_state<endc_disabled_st>() and not is_in_state<endc_deactivated_st>();
+}
+
+bool rrc::ue::rrc_endc::skip_rel_req(const sgnb_rel_req_ev& ev)
+{
+  return not requires_rel_req(ev) and not is_in_state<disable_endc_ev>();
+}
+
 } // namespace srsenb

srsenb/src/stack/rrc/rrc_nr.cc

@@ -538,8 +538,12 @@ int rrc_nr::sgnb_release_request(uint16_t nr_rnti)
 {
   task_sched.defer_task([this, nr_rnti]() {
     // remove user
+    auto     it         = users.find(nr_rnti);
+    uint16_t eutra_rnti = it != users.end() ? it->second->get_eutra_rnti() : SRSRAN_INVALID_RNTI;
     rem_user(nr_rnti);
-    rrc_eutra->sgnb_release_ack(nr_rnti);
+    if (eutra_rnti != SRSRAN_INVALID_RNTI) {
+      rrc_eutra->sgnb_release_ack(eutra_rnti);
+    }
   });
   return SRSRAN_SUCCESS;
 }