send connection reject if MME isn't connected

lib/include/srslte/interfaces/enb_interfaces.h

@@ -280,6 +280,7 @@ public:
   virtual bool user_release(uint16_t rnti, LIBLTE_S1AP_CAUSERADIONETWORK_ENUM cause_radio) = 0;
   virtual void ue_ctxt_setup_complete(uint16_t rnti, LIBLTE_S1AP_MESSAGE_INITIALCONTEXTSETUPRESPONSE_STRUCT *res) = 0;
   virtual void ue_erab_setup_complete(uint16_t rnti, LIBLTE_S1AP_MESSAGE_E_RABSETUPRESPONSE_STRUCT *res) = 0;
+  virtual bool is_mme_connected() = 0;
   // virtual void ue_capabilities(uint16_t rnti, LIBLTE_RRC_UE_EUTRA_CAPABILITY_STRUCT *caps) = 0;
 };
 

srsenb/hdr/upper/rrc.h

@@ -198,6 +198,7 @@ public:
 
     void send_connection_setup(bool is_setup = true);
     void send_connection_reest();
+    void send_connection_reject();
     void send_connection_release();
     void send_connection_reest_rej();
     void send_connection_reconf(srslte::byte_buffer_t *sdu);

srsenb/hdr/upper/s1ap.h

@@ -80,6 +80,7 @@ public:
   bool user_release(uint16_t rnti, LIBLTE_S1AP_CAUSERADIONETWORK_ENUM cause_radio);
   void ue_ctxt_setup_complete(uint16_t rnti, LIBLTE_S1AP_MESSAGE_INITIALCONTEXTSETUPRESPONSE_STRUCT *res);
   void ue_erab_setup_complete(uint16_t rnti, LIBLTE_S1AP_MESSAGE_E_RABSETUPRESPONSE_STRUCT *res);
+  bool is_mme_connected();
   //void ue_capabilities(uint16_t rnti, LIBLTE_RRC_UE_EUTRA_CAPABILITY_STRUCT *caps);
 
 private:

srsenb/src/upper/rrc.cc

@@ -1044,6 +1044,12 @@ void rrc::ue::parse_ul_dcch(uint32_t lcid, byte_buffer_t *pdu)
 
 void rrc::ue::handle_rrc_con_req(LIBLTE_RRC_CONNECTION_REQUEST_STRUCT *msg)
 {
+  if (not parent->s1ap->is_mme_connected()) {
+    printf("send reject\n");
+    parent->rrc_log->error("MME isn't connected. Sending Connection Reject\n");
+    send_connection_reject();
+  }
+
   set_activity();
   
   if(msg->ue_id_type == LIBLTE_RRC_CON_REQ_UE_ID_TYPE_S_TMSI) {
@@ -1303,7 +1309,17 @@ void rrc::ue::send_connection_reest_rej()
   dl_ccch_msg.msg_type = LIBLTE_RRC_DL_CCCH_MSG_TYPE_RRC_CON_REEST_REJ;
   
   send_dl_ccch(&dl_ccch_msg);
+}
 
+void rrc::ue::send_connection_reject()
+{
+  LIBLTE_RRC_DL_CCCH_MSG_STRUCT dl_ccch_msg;
+  bzero(&dl_ccch_msg, sizeof(LIBLTE_RRC_DL_CCCH_MSG_STRUCT));
+
+  dl_ccch_msg.msg_type = LIBLTE_RRC_DL_CCCH_MSG_TYPE_RRC_CON_REJ;
+  dl_ccch_msg.msg.rrc_con_rej.wait_time = 10;
+
+  send_dl_ccch(&dl_ccch_msg);
 }
 
 void rrc::ue::send_connection_setup(bool is_setup)

srsenb/src/upper/s1ap.cc

@@ -259,6 +259,11 @@ void s1ap::ue_erab_setup_complete(uint16_t rnti, LIBLTE_S1AP_MESSAGE_E_RABSETUPR
 
 //}
 
+bool s1ap::is_mme_connected()
+{
+  return mme_connected;
+}
+
 /*******************************************************************************
 /* S1AP connection helpers
 ********************************************************************************/