lte,enb,rrc: verify the drbtoaddmodlist is correctly updated in the add_erab case, and change the function add_erab to addmod_erab

srsenb/hdr/stack/rrc/rrc_bearer_cfg.h

@@ -93,12 +93,12 @@ public:
   /// Called after RRCReestablishmentComplete, to add E-RABs of old rnti
   void reestablish_bearers(bearer_cfg_handler&& old_rnti_bearers);
 
-  int  add_erab(uint8_t                                            erab_id,
-                const asn1::s1ap::erab_level_qos_params_s&         qos,
-                const asn1::bounded_bitstring<1, 160, true, true>& addr,
-                uint32_t                                           teid_out,
-                srsran::const_span<uint8_t>                        nas_pdu,
-                asn1::s1ap::cause_c&                               cause);
+  int  addmod_erab(uint8_t                                            erab_id,
+                   const asn1::s1ap::erab_level_qos_params_s&         qos,
+                   const asn1::bounded_bitstring<1, 160, true, true>& addr,
+                   uint32_t                                           teid_out,
+                   srsran::const_span<uint8_t>                        nas_pdu,
+                   asn1::s1ap::cause_c&                               cause);
   int  release_erab(uint8_t erab_id);
   void release_erabs();
   int  modify_erab(uint8_t                                    erab_id,

srsenb/src/stack/rrc/rrc_bearer_cfg.cc

@@ -212,12 +212,12 @@ void bearer_cfg_handler::reestablish_bearers(bearer_cfg_handler&& old_rnti_beare
   old_rnti_bearers.current_drbs.clear();
 }
 
-int bearer_cfg_handler::add_erab(uint8_t                                            erab_id,
-                                 const asn1::s1ap::erab_level_qos_params_s&         qos,
-                                 const asn1::bounded_bitstring<1, 160, true, true>& addr,
-                                 uint32_t                                           teid_out,
-                                 srsran::const_span<uint8_t>                        nas_pdu,
-                                 asn1::s1ap::cause_c&                               cause)
+int bearer_cfg_handler::addmod_erab(uint8_t                                            erab_id,
+                                    const asn1::s1ap::erab_level_qos_params_s&         qos,
+                                    const asn1::bounded_bitstring<1, 160, true, true>& addr,
+                                    uint32_t                                           teid_out,
+                                    srsran::const_span<uint8_t>                        nas_pdu,
+                                    asn1::s1ap::cause_c&                               cause)
 {
   if (erab_id < 5) {
     logger->error("ERAB id=%d is invalid", erab_id);
@@ -281,6 +281,16 @@ int bearer_cfg_handler::add_erab(uint8_t
     }
   }
 
+  // If it is an E-RAB modification, remove previous DRB object
+  if (erabs.count(erab_id) > 0) {
+    for (auto& drb : current_drbs) {
+      if (drb.eps_bearer_id_present and drb.eps_bearer_id == erab_id) {
+        srsran::rem_rrc_obj_id(current_drbs, drb.drb_id);
+        break;
+      }
+    }
+  }
+
   // Consider ERAB as accepted
   erabs[erab_id].id         = erab_id;
   erabs[erab_id].lcid       = lcid;
@@ -352,7 +362,7 @@ int bearer_cfg_handler::modify_erab(uint8_t                                    e
   }
   auto     address  = erab_it->second.address;
   uint32_t teid_out = erab_it->second.teid_out;
-  return add_erab(erab_id, qos, address, teid_out, nas_pdu, cause);
+  return addmod_erab(erab_id, qos, address, teid_out, nas_pdu, cause);
 }
 
 int bearer_cfg_handler::add_gtpu_bearer(uint32_t erab_id)

srsenb/src/stack/rrc/rrc_mobility.cc

@@ -952,7 +952,7 @@ bool rrc::ue::rrc_mobility::apply_ho_prep_cfg(const ho_prep_info_r8_ies_s&
     uint32_t teid_out = 0;
     srsran::uint8_to_uint32(erab.gtp_teid.data(), &teid_out);
     asn1::s1ap::cause_c erab_cause;
-    if (rrc_ue->bearer_list.add_erab(
+    if (rrc_ue->bearer_list.addmod_erab(
             erab.erab_id, erab.erab_level_qos_params, erab.transport_layer_address, teid_out, {}, erab_cause) !=
         SRSRAN_SUCCESS) {
       erabs_failed_to_setup.emplace_back();

srsenb/src/stack/rrc/rrc_ue.cc

@@ -1219,7 +1219,7 @@ int rrc::ue::setup_erab(uint16_t                                           erab_
     cause.set_radio_network().value = asn1::s1ap::cause_radio_network_opts::multiple_erab_id_instances;
     return SRSRAN_ERROR;
   }
-  if (bearer_list.add_erab(erab_id, qos_params, addr, gtpu_teid_out, nas_pdu, cause) != SRSRAN_SUCCESS) {
+  if (bearer_list.addmod_erab(erab_id, qos_params, addr, gtpu_teid_out, nas_pdu, cause) != SRSRAN_SUCCESS) {
     parent->logger.error("Couldn't add E-RAB id=%d for rnti=0x%x", erab_id, rnti);
     return SRSRAN_ERROR;
   }