nr,gnb,rrc: avoid warning when eutra requests sgnb release and destroys the UE before acknowledgement

srsenb/hdr/stack/rrc/rrc_endc.h

@@ -127,7 +127,6 @@ private:
 
   // 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);
@@ -168,7 +167,6 @@ protected:
   upd< endc_activated_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

@@ -605,13 +605,14 @@ void rrc::sgnb_addition_complete(uint16_t eutra_rnti, uint16_t nr_rnti)
 
 void rrc::sgnb_release_ack(uint16_t eutra_rnti)
 {
-  logger.info("Received SgNB release 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);
-    return;
+  if (ue_it != users.end()) {
+    logger.info("Received SgNB release acknowledgement for rnti=0x%x", eutra_rnti);
+    ue_it->second->endc_handler->trigger(ue::rrc_endc::sgnb_rel_req_ack_ev{});
+  } else {
+    // The EUTRA does not need to wait for Release Ack in case it wants to destroy the EUTRA UE
+    logger.info("Received SgNB release acknowledgement for already released rnti=0x%x", eutra_rnti);
   }
-  ue_it->second->endc_handler->trigger(ue::rrc_endc::sgnb_rel_req_ack_ev{});
 }
 
 /*******************************************************************************

srsenb/src/stack/rrc/rrc_endc.cc

@@ -383,12 +383,8 @@ void rrc::ue::rrc_endc::handle_endc_disabled(const disable_endc_ev& ev)
 
 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>();
+  return not is_in_state<endc_disabled_st>() and not is_in_state<endc_deactivated_st>() and
+         not is_in_state<wait_sgnb_rel_req_resp_st>();
 }
 
 } // namespace srsenb