fix rrc and gtpu bearer rnti update during reestablishment. The rnti of UE's rrc_bearer_handler was not being updated

srsenb/hdr/stack/rrc/rrc_bearer_cfg.h

@@ -79,6 +79,9 @@ public:
 
   bearer_cfg_handler(uint16_t rnti_, const rrc_cfg_t& cfg_, gtpu_interface_rrc* gtpu_);
 
+  /// 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,

srsenb/src/stack/rrc/rrc_bearer_cfg.cc

@@ -204,6 +204,14 @@ bearer_cfg_handler::bearer_cfg_handler(uint16_t rnti_, const rrc_cfg_t& cfg_, gt
   rnti(rnti_), cfg(&cfg_), gtpu(gtpu_), logger(&srslog::fetch_basic_logger("RRC"))
 {}
 
+void bearer_cfg_handler::reestablish_bearers(bearer_cfg_handler&& old_rnti_bearers)
+{
+  erab_info_list = std::move(old_rnti_bearers.erab_info_list);
+  erabs          = std::move(old_rnti_bearers.erabs);
+  current_drbs   = std::move(old_rnti_bearers.current_drbs);
+  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,

srsenb/src/stack/rrc/rrc_ue.cc

@@ -665,8 +665,8 @@ void rrc::ue::handle_rrc_con_reest_complete(rrc_conn_reest_complete_s* msg, srsr
   parent->pdcp->enable_integrity(rnti, srb_to_lcid(lte_srb::srb1));
   parent->pdcp->enable_encryption(rnti, srb_to_lcid(lte_srb::srb1));
 
-  // Reestablish current DRBs during ConnectionReconfiguration
-  bearer_list = std::move(parent->users.at(old_reest_rnti)->bearer_list);
+  // Reestablish E-RABs of old rnti during ConnectionReconfiguration
+  bearer_list.reestablish_bearers(std::move(parent->users.at(old_reest_rnti)->bearer_list));
 
   // remove old RNTI
   parent->rem_user_thread(old_reest_rnti);

srsenb/src/stack/upper/gtpu.cc

@@ -126,16 +126,20 @@ bool gtpu_tunnel_manager::update_rnti(uint16_t old_rnti, uint16_t new_rnti)
   auto* old_rnti_ptr = find_rnti_tunnels(old_rnti);
   logger.info("Modifying bearer rnti. Old rnti: 0x%x, new rnti: 0x%x", old_rnti, new_rnti);
 
-  // Change RNTI bearers map
-  ue_teidin_db.insert(new_rnti, std::move(*old_rnti_ptr));
-  ue_teidin_db.erase(old_rnti);
-
-  // Change TEID in existing tunnels
-  auto* new_rnti_ptr = find_rnti_tunnels(new_rnti);
-  for (lcid_tunnel& bearer : *new_rnti_ptr) {
+  // create new RNTI and update TEIDs of old rnti to reflect new rnti
+  if (not ue_teidin_db.insert(new_rnti, ue_lcid_tunnel_list())) {
+    logger.error("Failure to create new rnti=0x%x", new_rnti);
+    return false;
+  }
+  std::swap(ue_teidin_db[new_rnti], *old_rnti_ptr);
+  auto& new_rnti_obj = ue_teidin_db[new_rnti];
+  for (lcid_tunnel& bearer : new_rnti_obj) {
     tunnels[bearer.teid].rnti = new_rnti;
   }
 
+  // Leave old_rnti as zombie to be removed later
+  old_rnti_ptr->clear();
+
   return true;
 }