fix issue #1418 by changing the ConRes CE scheduling mechanism

srsenb/src/stack/mac/mac.cc

@@ -36,10 +36,7 @@ using namespace asn1::rrc;
 
 namespace srsenb {
 
-mac::mac() :
-  rar_pdu_msg(sched_interface::MAX_RAR_LIST),
-  rar_payload(),
-  common_buffers(SRSLTE_MAX_CARRIERS)
+mac::mac() : rar_pdu_msg(sched_interface::MAX_RAR_LIST), rar_payload(), common_buffers(SRSLTE_MAX_CARRIERS)
 {
   pthread_rwlock_init(&rwlock, nullptr);
 }
@@ -268,7 +265,6 @@ int mac::ue_set_crnti(uint16_t temp_crnti, uint16_t crnti, sched_interface::ue_c
   if (ret != SRSLTE_SUCCESS) {
     return ret;
   }
-  scheduler.dl_mac_buffer_state(crnti, (uint32_t)srslte::dl_sch_lcid::CON_RES_ID);
   return ret;
 }
 
@@ -517,7 +513,6 @@ void mac::rach_detected(uint32_t tti, uint32_t enb_cc_idx, uint32_t preamble_idx
     ue_cfg.supported_cc_list.emplace_back();
     ue_cfg.supported_cc_list.back().active     = true;
     ue_cfg.supported_cc_list.back().enb_cc_idx = enb_cc_idx;
-    ue_cfg.ue_bearers[0].direction             = srsenb::sched_interface::ue_bearer_cfg_t::BOTH;
     ue_cfg.dl_cfg.tm                           = SRSLTE_TM1;
     if (scheduler.ue_cfg(rnti, ue_cfg) != SRSLTE_SUCCESS) {
       Error("Registering new user rnti=0x%x to SCHED\n", rnti);
@@ -536,6 +531,9 @@ void mac::rach_detected(uint32_t tti, uint32_t enb_cc_idx, uint32_t preamble_idx
     // Trigger scheduler RACH
     scheduler.dl_rach_info(enb_cc_idx, rar_info);
 
+    // Schedule ConRes Msg4
+    scheduler.dl_mac_buffer_state(rnti, (uint32_t)srslte::dl_sch_lcid::CON_RES_ID);
+
     log_h->info("RACH:  tti=%d, preamble=%d, offset=%d, temp_crnti=0x%x\n", tti, preamble_idx, time_adv, rnti);
     log_h->console("RACH:  tti=%d, preamble=%d, offset=%d, temp_crnti=0x%x\n", tti, preamble_idx, time_adv, rnti);
   });

srsenb/src/stack/mac/scheduler_ue.cc

@@ -879,7 +879,6 @@ std::pair<uint32_t, uint32_t> sched_ue::get_requested_dl_bytes(uint32_t ue_cc_id
   // Ensure there is space for ConRes and RRC Setup
   // SRB0 is a special case due to being RLC TM (no segmentation possible)
   if (not bearer_is_dl(&lch[0])) {
-    log_h->error("SRB0 must always be activated for DL\n");
     return {0, 0};
   }
   if (not carriers[ue_cc_idx].is_active()) {

srsenb/src/stack/rrc/rrc_ue.cc

@@ -328,6 +328,11 @@ void rrc::ue::handle_rrc_con_setup_complete(rrc_conn_setup_complete_s* msg, srsl
 
 void rrc::ue::send_connection_reject()
 {
+  // Activate SRB0 if not yet activated
+  sched_interface::ue_bearer_cfg_t srb0{};
+  srb0.direction = sched_interface::ue_bearer_cfg_t::DL;
+  parent->mac->bearer_ue_cfg(rnti, 0, &srb0);
+
   dl_ccch_msg_s dl_ccch_msg;
   dl_ccch_msg.msg.set_c1().set_rrc_conn_reject().crit_exts.set_c1().set_rrc_conn_reject_r8().wait_time = 10;
   send_dl_ccch(&dl_ccch_msg);