send DL-DCCH on SRB2 after it has been established

lib/include/srslte/interfaces/enb_interfaces.h

@@ -194,6 +194,7 @@ public:
   virtual void add_bearer(uint16_t rnti, uint32_t lcid, srslte::rlc_config_t cnfg)        = 0;
   virtual void add_bearer_mrb(uint16_t rnti, uint32_t lcid) = 0;
   virtual void write_sdu(uint16_t rnti, uint32_t lcid, srslte::unique_byte_buffer_t sdu)  = 0;
+  virtual bool has_bearer(uint16_t rnti, uint32_t lcid)                                   = 0;
 };
 
 // PDCP interface for GTPU

srsenb/hdr/stack/upper/rlc.h

@@ -54,6 +54,7 @@ public:
   void rem_user(uint16_t rnti);
   void add_bearer(uint16_t rnti, uint32_t lcid, srslte::rlc_config_t cnfg);
   void add_bearer_mrb(uint16_t rnti, uint32_t lcid);
+  bool has_bearer(uint16_t rnti, uint32_t lcid);
 
   // rlc_interface_pdcp
   void        write_sdu(uint16_t rnti, uint32_t lcid, srslte::unique_byte_buffer_t sdu);

srsenb/src/stack/rrc/rrc.cc

@@ -2094,10 +2094,15 @@ void rrc::ue::send_dl_dcch(dl_dcch_msg_s* dl_dcch_msg, srslte::unique_byte_buffe
     dl_dcch_msg->pack(bref);
     pdu->N_bytes = 1u + (uint32_t)bref.distance_bytes(pdu->msg);
 
+    // send on SRB2 if user is fully registered (after RRC reconfig complete)
+    uint32_t lcid =
+        parent->rlc->has_bearer(rnti, RB_ID_SRB2) && state == RRC_STATE_REGISTERED ? RB_ID_SRB2 : RB_ID_SRB1;
+
     char buf[32] = {};
-    sprintf(buf, "SRB1 - rnti=0x%x", rnti);
+    sprintf(buf, "SRB%d - rnti=0x%x", lcid, rnti);
     parent->log_rrc_message(buf, Tx, pdu.get(), *dl_dcch_msg);
-    parent->pdcp->write_sdu(rnti, RB_ID_SRB1, std::move(pdu));
+
+    parent->pdcp->write_sdu(rnti, lcid, std::move(pdu));
   } else {
     parent->rrc_log->error("Allocating pdu\n");
   }

srsenb/src/stack/upper/rlc.cc

@@ -110,6 +110,17 @@ void rlc::add_bearer_mrb(uint16_t rnti, uint32_t lcid)
   pthread_rwlock_unlock(&rwlock);
 }
 
+bool rlc::has_bearer(uint16_t rnti, uint32_t lcid)
+{
+  pthread_rwlock_rdlock(&rwlock);
+  bool result = false;
+  if (users.count(rnti)) {
+    result = users[rnti].rlc->has_bearer(lcid);
+  }
+  pthread_rwlock_unlock(&rwlock);
+  return result;
+}
+
 void rlc::read_pdu_pcch(uint8_t* payload, uint32_t buffer_size)
 {
   rrc->read_pdu_pcch(payload, buffer_size);