enb,rrc: disable SRB2 in mac controller during handover. This is to

avoid transporting NAS messages before we received the RRC Reconf
 complete and the HO is finished.

srsenb/hdr/stack/rrc/mac_controller.h

@@ -61,6 +61,7 @@ public:
   bool            is_crnti_set() const { return crnti_set; }
 
   void set_scell_activation(const std::bitset<SRSRAN_MAX_CARRIERS>& scell_mask);
+  void set_srb2_activation(bool active);
   void set_drb_activation(bool active);
 
   void update_mac();

srsenb/src/stack/rrc/mac_controller.cc

@@ -137,6 +137,9 @@ int mac_controller::handle_crnti_ce(uint32_t temp_crnti)
     current_sched_ue_cfg.ue_bearers[i] = next_sched_ue_cfg.ue_bearers[i];
   }
 
+  // keep SRB2 disabled until RRCReconfComplete is received
+  set_srb2_activation(false);
+
   return mac->ue_set_crnti(temp_crnti, rnti, current_sched_ue_cfg);
 }
 
@@ -220,7 +223,10 @@ void mac_controller::handle_con_reconf_complete()
 {
   current_sched_ue_cfg = next_sched_ue_cfg;
 
-  // Setup all bearers
+  // Setup SRB2
+  set_srb2_activation(true);
+
+  // Setup all data bearers
   apply_current_bearers_cfg();
 
   // Apply SCell+Bearer changes to MAC
@@ -256,7 +262,9 @@ void mac_controller::handle_target_enb_ho_cmd(const asn1::rrc::rrc_conn_recfg_r8
   ue_cfg_apply_capabilities(next_sched_ue_cfg, *rrc_cfg, uecaps);
   ue_cfg_apply_reconf_complete_updates(next_sched_ue_cfg, conn_recfg, ue_cell_list);
 
-  // Temporarily freeze new allocations for DRBs (SRBs are needed to send RRC Reconf Message)
+  // Temporarily freeze SRB2 and DRBs. SRB1 is needed to send
+  // RRC Reconfiguration and receive RRC Reconfiguration Complete
+  set_srb2_activation(false);
   set_drb_activation(false);
 
   // Apply changes to MAC scheduler
@@ -320,6 +328,12 @@ void mac_controller::set_scell_activation(const std::bitset<SRSRAN_MAX_CARRIERS>
   }
 }
 
+void mac_controller::set_srb2_activation(bool active)
+{
+  current_sched_ue_cfg.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction =
+      active ? mac_lc_ch_cfg_t::BOTH : mac_lc_ch_cfg_t::IDLE;
+}
+
 void mac_controller::set_drb_activation(bool active)
 {
   for (const drb_to_add_mod_s& drb : bearer_list.get_established_drbs()) {

srsenb/test/rrc/rrc_mobility_test.cc

@@ -324,18 +324,17 @@ int test_s1ap_tenb_mobility(test_event test_params)
   TESTASSERT(mac_ue.supported_cc_list[0].enb_cc_idx == 0);
   TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb0)].direction == mac_lc_ch_cfg_t::BOTH);
   TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb1)].direction == mac_lc_ch_cfg_t::BOTH);
-  TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == mac_lc_ch_cfg_t::BOTH);
+  TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == mac_lc_ch_cfg_t::IDLE);
   TESTASSERT(mac_ue.ue_bearers[drb_to_lcid(lte_drb::drb1)].direction == mac_lc_ch_cfg_t::IDLE);
 
   tester.tic();
   TESTASSERT(tester.rrc.get_nof_users() == 1);
   TESTASSERT(tester.mac.ue_db.count(0x46));
-  // auto& mac_ue = tester.mac.ue_db[0x46];
   TESTASSERT(mac_ue.supported_cc_list[0].active);
   TESTASSERT(mac_ue.supported_cc_list[0].enb_cc_idx == 0);
   TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb0)].direction == mac_lc_ch_cfg_t::BOTH);
   TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb1)].direction == mac_lc_ch_cfg_t::BOTH);
-  TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == mac_lc_ch_cfg_t::BOTH);
+  TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == mac_lc_ch_cfg_t::IDLE);
   TESTASSERT(mac_ue.ue_bearers[drb_to_lcid(lte_drb::drb1)].direction == mac_lc_ch_cfg_t::IDLE);
   // Check Security Configuration
   TESTASSERT(tester.pdcp.bearers.count(0x46));
@@ -354,7 +353,7 @@ int test_s1ap_tenb_mobility(test_event test_params)
   TESTASSERT(tester.pdcp.bearers[0x46][srb_to_lcid(lte_srb::srb1)].sec_cfg.integ_algo == as_sec_cfg.integ_algo);
 
   TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb1)].direction == mac_lc_ch_cfg_t::BOTH);
-  TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == mac_lc_ch_cfg_t::BOTH);
+  TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == mac_lc_ch_cfg_t::IDLE);
   TESTASSERT(mac_ue.ue_bearers[drb_to_lcid(lte_drb::drb1)].direction == mac_lc_ch_cfg_t::IDLE);
 
   // Check if S1AP Handover Request ACK send is called
@@ -373,7 +372,7 @@ int test_s1ap_tenb_mobility(test_event test_params)
   auto& recfg_r8 = dl_dcch_msg.msg.c1().rrc_conn_recfg().crit_exts.c1().rrc_conn_recfg_r8();
 
   TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb1)].direction == mac_lc_ch_cfg_t::BOTH);
-  TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == mac_lc_ch_cfg_t::BOTH);
+  TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == mac_lc_ch_cfg_t::IDLE);
   TESTASSERT(mac_ue.ue_bearers[drb_to_lcid(lte_drb::drb1)].direction == mac_lc_ch_cfg_t::IDLE);
 
   // Receives MMEStatusTransfer
@@ -393,7 +392,7 @@ int test_s1ap_tenb_mobility(test_event test_params)
   TESTASSERT(tester.pdcp.bearers[0x46][3].state.rx_hfn == 4);
 
   TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb1)].direction == mac_lc_ch_cfg_t::BOTH);
-  TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == mac_lc_ch_cfg_t::BOTH);
+  TESTASSERT(mac_ue.ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == mac_lc_ch_cfg_t::IDLE);
   TESTASSERT(mac_ue.ue_bearers[drb_to_lcid(lte_drb::drb1)].direction == mac_lc_ch_cfg_t::IDLE);
 
   // user PRACHs and sends C-RNTI CE
@@ -511,7 +510,8 @@ int test_intraenb_mobility(srsran::log_sink_spy& spy, test_event test_params)
   TESTASSERT(tester.phy.last_cfg[0].enb_cc_idx == ue_cfg->supported_cc_list[0].enb_cc_idx);
   TESTASSERT(ue_cfg->ue_bearers[srb_to_lcid(lte_srb::srb0)].direction == srsenb::mac_lc_ch_cfg_t::BOTH);
   TESTASSERT(ue_cfg->ue_bearers[srb_to_lcid(lte_srb::srb1)].direction == srsenb::mac_lc_ch_cfg_t::BOTH);
-  TESTASSERT(ue_cfg->ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == srsenb::mac_lc_ch_cfg_t::BOTH);
+  TESTASSERT(ue_cfg->ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == srsenb::mac_lc_ch_cfg_t::IDLE);
+  TESTASSERT(ue_cfg->ue_bearers[drb_to_lcid(lte_drb::drb1)].direction == srsenb::mac_lc_ch_cfg_t::IDLE);
 
   /* Test Case: The UE receives a duplicate C-RNTI CE. Nothing should happen */
   if (test_params == test_event::duplicate_crnti_ce) {
@@ -525,7 +525,8 @@ int test_intraenb_mobility(srsran::log_sink_spy& spy, test_event test_params)
   /* Test Case: Terminate first Handover. No extra messages should be sent DL. SR/CQI resources match recfg message */
   uint8_t recfg_complete[] = {0x10, 0x00};
   copy_msg_to_buffer(pdu, recfg_complete);
-  tester.rrc.write_pdu(tester.rnti, srb_to_lcid(lte_srb::srb2), std::move(pdu));
+  tester.rrc.write_pdu(tester.rnti, srb_to_lcid(lte_srb::srb1), std::move(pdu));
+  tester.tic();
   TESTASSERT(tester.pdcp.last_sdu.sdu == nullptr);
   ue_cfg = &tester.mac.ue_db[tester.rnti];
   TESTASSERT(ue_cfg->pucch_cfg.sr_configured);
@@ -534,6 +535,10 @@ int test_intraenb_mobility(srsran::log_sink_spy& spy, test_event test_params)
   TESTASSERT(ue_cfg->supported_cc_list[0].dl_cfg.cqi_report.pmi_idx ==
              phy_cfg_ded.cqi_report_cfg.cqi_report_periodic.setup().cqi_pmi_cfg_idx);
   TESTASSERT(ue_cfg->pucch_cfg.n_pucch == phy_cfg_ded.cqi_report_cfg.cqi_report_periodic.setup().cqi_pucch_res_idx);
+  TESTASSERT(ue_cfg->ue_bearers[srb_to_lcid(lte_srb::srb0)].direction == srsenb::mac_lc_ch_cfg_t::BOTH);
+  TESTASSERT(ue_cfg->ue_bearers[srb_to_lcid(lte_srb::srb1)].direction == srsenb::mac_lc_ch_cfg_t::BOTH);
+  TESTASSERT(ue_cfg->ue_bearers[srb_to_lcid(lte_srb::srb2)].direction == srsenb::mac_lc_ch_cfg_t::BOTH);
+  TESTASSERT(ue_cfg->ue_bearers[drb_to_lcid(lte_drb::drb1)].direction == srsenb::mac_lc_ch_cfg_t::BOTH);
 
   /* Test Case: The RRC should be able to start a new handover */
   uint8_t meas_report[] = {0x08, 0x10, 0x38, 0x74, 0x00, 0x05, 0xBC, 0x80}; // PCI == 1