Handle RRC ConnectionReject at eNodeB and UE

lib/include/srslte/interfaces/enb_interfaces.h

@@ -259,7 +259,8 @@ public:
   virtual bool user_exists(uint16_t rnti) = 0; 
   virtual void user_inactivity(uint16_t rnti) = 0;
   virtual void release_eutran(uint16_t rnti) = 0; 
-  virtual bool user_link_lost(uint16_t rnti) = 0; 
+  virtual bool user_link_lost(uint16_t rnti) = 0;
+  virtual bool is_connected() = 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 void ue_capabilities(uint16_t rnti, LIBLTE_RRC_UE_EUTRA_CAPABILITY_STRUCT *caps) = 0;

lib/include/srslte/interfaces/ue_interfaces.h

@@ -97,9 +97,19 @@ public:
 class nas_interface_rrc
 {
 public:
+
+  typedef enum {
+    BARRING_MT_ACCESS       = 1,
+    BARRING_MO_CALL         = 2,
+    BARRING_MO_SIGNALLING   = 4,
+    BARRING_ALL             = 7
+  } cell_barring_type_t;
+
   virtual bool      is_attached() = 0;
   virtual bool      is_attaching() = 0;
   virtual void      notify_connection_setup() = 0;
+  virtual void      notify_connection_failure() = 0;
+  virtual void      network_barring_state(bool is_barred, uint32_t type_mask = BARRING_ALL) = 0;
   virtual void      write_pdu(uint32_t lcid, srslte::byte_buffer_t *pdu) = 0;
   virtual uint32_t  get_ul_count() = 0;
   virtual bool      get_s_tmsi(LIBLTE_RRC_S_TMSI_STRUCT *s_tmsi) = 0;

srsenb/hdr/upper/rrc.h

@@ -172,7 +172,8 @@ public:
     rrc_state_t get_state();
     
     void send_connection_setup(bool is_setup = true);
-    void send_connection_reest(); 
+    void send_connection_rej();
+    void send_connection_reest();
     void send_connection_release();
     void send_connection_reest_rej(); 
     void send_connection_reconf(srslte::byte_buffer_t *sdu);

srsenb/hdr/upper/s1ap.h

@@ -79,7 +79,8 @@ public:
   bool user_exists(uint16_t rnti); 
   void user_inactivity(uint16_t rnti);
   bool user_link_lost(uint16_t rnti);
-  void release_eutran(uint16_t rnti); 
+  void release_eutran(uint16_t rnti);
+  bool is_connected();
   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);
   //void ue_capabilities(uint16_t rnti, LIBLTE_RRC_UE_EUTRA_CAPABILITY_STRUCT *caps);

srsenb/src/upper/rrc.cc

@@ -833,14 +833,20 @@ 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)
 {
   set_activity();
-  
+
-  if(msg->ue_id_type == LIBLTE_RRC_CON_REQ_UE_ID_TYPE_S_TMSI) {
+  if (parent->s1ap->is_connected()) {
-    mmec      = msg->ue_id.s_tmsi.mmec;
+    if(msg->ue_id_type == LIBLTE_RRC_CON_REQ_UE_ID_TYPE_S_TMSI) {
-    m_tmsi    = msg->ue_id.s_tmsi.m_tmsi;
+      mmec      = msg->ue_id.s_tmsi.mmec;
-    has_tmsi = true;
+      m_tmsi    = msg->ue_id.s_tmsi.m_tmsi;
+      has_tmsi = true;
+    }
+    send_connection_setup();
+    state = RRC_STATE_WAIT_FOR_CON_SETUP_COMPLETE;
+  } else {
+    parent->rrc_log->info("Received ConnectionRequest with no active S1 link\n");
+    parent->rrc_log->console("Received ConnectionRequest with no active S1 link\n");
+    send_connection_rej();
   }
-  send_connection_setup();
-  state = RRC_STATE_WAIT_FOR_CON_SETUP_COMPLETE;
 }
 
 void rrc::ue::handle_rrc_con_reest_req(LIBLTE_RRC_CONNECTION_REESTABLISHMENT_REQUEST_STRUCT *msg)
@@ -1054,6 +1060,16 @@ void rrc::ue::send_connection_reest_rej()
   
 }
 
+void rrc::ue::send_connection_rej()
+{
+  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)
 {
   LIBLTE_RRC_DL_CCCH_MSG_STRUCT dl_ccch_msg; 

srsenb/src/upper/s1ap.cc

@@ -170,6 +170,11 @@ void s1ap::build_tai_cgi()
 /*******************************************************************************
 /* RRC interface
 ********************************************************************************/
+
+bool s1ap::is_connected() {
+  return mme_connected;
+}
+
 void s1ap::initial_ue(uint16_t rnti, srslte::byte_buffer_t *pdu)
 {
   ue_ctxt_map[rnti].eNB_UE_S1AP_ID = next_eNB_UE_S1AP_ID++;
@@ -226,7 +231,6 @@ void s1ap::user_inactivity(uint16_t rnti)
   send_uectxtreleaserequest(rnti, &cause);
 }
 
-
 void s1ap::release_eutran(uint16_t rnti)
 {
   s1ap_log->info("Release by EUTRAN - RNTI:0x%x\n", rnti);

srsue/hdr/upper/nas.h

@@ -80,6 +80,9 @@ public:
 
   // RRC interface
   void notify_connection_setup();
+  void notify_connection_failure();
+  void network_barring_state(bool is_barred, uint32_t type_mask);
+
 
   void write_pdu(uint32_t lcid, byte_buffer_t *pdu);
 
@@ -135,6 +138,9 @@ private:
   uint8_t k_nas_enc[32];
   uint8_t k_nas_int[32];
 
+  bool network_is_barred;
+  uint32_t network_barring_type;
+
   srslte::CIPHERING_ALGORITHM_ID_ENUM cipher_algo;
   srslte::INTEGRITY_ALGORITHM_ID_ENUM integ_algo;
 

srsue/hdr/upper/rrc.h

@@ -127,7 +127,7 @@ private:
   srslte::mac_interface_timers *mac_timers;
   uint32_t n310_cnt, N310;
   uint32_t n311_cnt, N311;
-  uint32_t t301, t310, t311;
+  uint32_t t300, t301, t302, t310, t311;
   int ue_category;
 
   typedef struct {
@@ -240,15 +240,15 @@ private:
   // Parsers
   void          parse_dl_ccch(byte_buffer_t *pdu);
   void          parse_dl_dcch(uint32_t lcid, byte_buffer_t *pdu);
-  void          parse_dl_info_transfer(uint32_t lcid, byte_buffer_t *pdu);
 
   // Helpers
+  void          timer_t300_expiry();
+  void          timer_barring_expiry(uint32_t timer_id);
   void          rrc_connection_release();
   void          radio_link_failure(); 
-  static void*  start_sib_thread(void *rrc_);
-  void          sib_search();
   void          apply_sib2_configs(LIBLTE_RRC_SYS_INFO_BLOCK_TYPE_2_STRUCT *sib2);
   void          handle_con_setup(LIBLTE_RRC_CONNECTION_SETUP_STRUCT *setup);
+  void          handle_con_rej(LIBLTE_RRC_CONNECTION_REJECT_STRUCT *reject);
   void          handle_con_reest(LIBLTE_RRC_CONNECTION_REESTABLISHMENT_STRUCT *setup);
   void          handle_rrc_con_reconfig(uint32_t lcid, LIBLTE_RRC_CONNECTION_RECONFIGURATION_STRUCT *reconfig, byte_buffer_t *pdu);
   void          add_srb(LIBLTE_RRC_SRB_TO_ADD_MOD_STRUCT *srb_cnfg);

srsue/src/upper/nas.cc

@@ -66,22 +66,27 @@ UE interface
 *******************************************************************************/
 void nas::attach_request() {
   nas_log->info("Attach Request\n");
-  if (state == EMM_STATE_DEREGISTERED) {
+  if (!network_is_barred) {
-    state = EMM_STATE_REGISTERED_INITIATED;
+    if (state == EMM_STATE_DEREGISTERED) {
-    if (plmn_selection == PLMN_NOT_SELECTED) {
+      state = EMM_STATE_REGISTERED_INITIATED;
-      nas_log->info("Starting PLMN Search...\n");
+      if (plmn_selection == PLMN_NOT_SELECTED) {
-      rrc->plmn_search();
+        nas_log->info("Starting PLMN Search...\n");
-    } else if (plmn_selection == PLMN_SELECTED) {
+        rrc->plmn_search();
-      nas_log->info("Selecting PLMN %s\n", plmn_id_to_c_str(current_plmn).c_str());
+      } else if (plmn_selection == PLMN_SELECTED) {
+        nas_log->info("Selecting PLMN %s\n", plmn_id_to_c_str(current_plmn).c_str());
+        rrc->plmn_select(current_plmn);
+        selecting_plmn = current_plmn;
+      }
+    } else if (state == EMM_STATE_REGISTERED) {
+      nas_log->info("NAS state is registered, connecting to same PLMN\n");
       rrc->plmn_select(current_plmn);
       selecting_plmn = current_plmn;
+    } else {
+      nas_log->info("Attach request ignored. State = %s\n", emm_state_text[state]);
     }
-  } else if (state == EMM_STATE_REGISTERED) {
-    nas_log->info("NAS state is registered, connecting to same PLMN\n");
-    rrc->plmn_select(current_plmn);
-    selecting_plmn = current_plmn;
   } else {
-    nas_log->info("Attach request ignored. State = %s\n", emm_state_text[state]);
+    nas_log->info("Requested connection while network is barred\n");
+    nas_log->console("Requested connection while network is barred\n");
   }
 }
 
@@ -94,6 +99,12 @@ void nas::deattach_request() {
 RRC interface
 *******************************************************************************/
 
+void nas::network_barring_state(bool is_barred, uint32_t type_mask)
+{
+  network_is_barred    = is_barred;
+  network_barring_type = type_mask;
+}
+
 void nas::plmn_found(LIBLTE_RRC_PLMN_IDENTITY_STRUCT plmn_id, uint16_t tracking_area_code) {
 
   // Store PLMN if not registered
@@ -125,6 +136,12 @@ bool nas::is_attaching() {
   return state == EMM_STATE_REGISTERED_INITIATED;
 }
 
+void nas::notify_connection_failure() {
+  nas_log->info("Received RRC connection request failure\n");
+  nas_log->console("Connection Request Failure\n");
+  state = EMM_STATE_DEREGISTERED;
+}
+
 void nas::notify_connection_setup() {
   nas_log->debug("State = %s\n", emm_state_text[state]);
   if (EMM_STATE_REGISTERED_INITIATED == state) {

srsue/src/upper/rrc.cc

@@ -93,7 +93,9 @@ void rrc::init(phy_interface_rrc *phy_,
   pthread_mutex_init(&mutex, NULL);
 
   ue_category = SRSLTE_UE_CATEGORY;
+  t300 = mac_timers->timer_get_unique_id();
   t301 = mac_timers->timer_get_unique_id();
+  t302 = mac_timers->timer_get_unique_id();
   t310 = mac_timers->timer_get_unique_id();
   t311 = mac_timers->timer_get_unique_id();
 
@@ -538,14 +540,20 @@ void rrc::max_retx_attempted() {
 }
 
 void rrc::timer_expired(uint32_t timeout_id) {
-  if (timeout_id == t310) {
+  if (timeout_id == t300) {
+    rrc_log->info("Timer T300 expired: ConnectionRequest timeout\n");
+    timer_t300_expiry();
+  } else if (timeout_id == t301) {
+    rrc_log->info("Timer T301 expired: ConnectionReestablishmentRequest timeout\n");
+    state = RRC_STATE_LEAVE_CONNECTED;
+  } else if (timeout_id == t302) {
+    rrc_log->info("Timer T302 expired: ConnectionReject Wait time expired\n");
+    timer_barring_expiry(timeout_id);
+  } else if (timeout_id == t310) {
     rrc_log->info("Timer T310 expired: Radio Link Failure\n");
     radio_link_failure();
   } else if (timeout_id == t311) {
-    rrc_log->info("Timer T311 expired: Going to RRC IDLE\n");
+    rrc_log->info("Timer T311 expired: Start of Reestablishment procedure timeout\n");
-    state = RRC_STATE_LEAVE_CONNECTED;
-  } else if (timeout_id == t301) {
-    rrc_log->info("Timer T301 expired: Going to RRC IDLE\n");
     state = RRC_STATE_LEAVE_CONNECTED;
   } else {
     rrc_log->error("Timeout from unknown timer id %d\n", timeout_id);
@@ -608,6 +616,10 @@ void rrc::send_con_request() {
 
   mac->set_contention_id(uecri);
 
+  // Start t300 timer
+  mac_timers->timer_get(t300)->reset();
+  mac_timers->timer_get(t300)->run();
+
   rrc_log->info("Sending RRC Connection Request on SRB0\n");
   pdcp->write_sdu(RB_ID_SRB0, pdcp_buf);
 }
@@ -750,7 +762,6 @@ void rrc::send_con_setup_complete(byte_buffer_t *nas_msg) {
   pdcp_buf->N_bytes = bit_buf.N_bits / 8;
   pdcp_buf->set_timestamp();
 
-  state = RRC_STATE_CONNECTED;
   rrc_log->console("RRC Connected\n");
   rrc_log->info("Sending RRC Connection Setup Complete\n");
   pdcp->write_sdu(RB_ID_SRB1, pdcp_buf);
@@ -857,13 +868,25 @@ void rrc::handle_rrc_con_reconfig(uint32_t lcid, LIBLTE_RRC_CONNECTION_RECONFIGU
   }
 }
 
-  /* Actions upon reception of RRCConnectionRelease 5.3.8.3 */
+/* Actions upon reception of RRCConnectionRelease 5.3.8.3 */
 void rrc::rrc_connection_release() {
   // Save idleModeMobilityControlInfo, etc.
   state = RRC_STATE_LEAVE_CONNECTED;
   rrc_log->console("Received RRC Connection Release\n");
 }
 
+// Actions upon expiry of t300 timer 5.3.3.6
+void rrc::timer_t300_expiry() {
+  mac->reset();
+  set_mac_default();
+  nas->notify_connection_failure();
+  state = RRC_STATE_IDLE;
+}
+
+// Actions upon expiry of timers related to cell barring 5.3.3.7
+void rrc::timer_barring_expiry(uint32_t timer_id) {
+  nas->network_barring_state(false);
+}
 
 
 
@@ -1082,20 +1105,14 @@ void rrc::parse_dl_ccch(byte_buffer_t *pdu) {
 
   switch (dl_ccch_msg.msg_type) {
     case LIBLTE_RRC_DL_CCCH_MSG_TYPE_RRC_CON_REJ:
-      rrc_log->info("Connection Reject received. Wait time: %d\n",
+      transaction_id = dl_ccch_msg.msg.rrc_con_setup.rrc_transaction_id;
-                    dl_ccch_msg.msg.rrc_con_rej.wait_time);
+      handle_con_rej(&dl_ccch_msg.msg.rrc_con_rej);
-      state = RRC_STATE_IDLE;
       break;
     case LIBLTE_RRC_DL_CCCH_MSG_TYPE_RRC_CON_SETUP:
-      rrc_log->info("Connection Setup received\n");
       transaction_id = dl_ccch_msg.msg.rrc_con_setup.rrc_transaction_id;
       handle_con_setup(&dl_ccch_msg.msg.rrc_con_setup);
-      rrc_log->info("Notifying NAS of connection setup\n");
-      nas->notify_connection_setup();
       break;
     case LIBLTE_RRC_DL_CCCH_MSG_TYPE_RRC_CON_REEST:
-      rrc_log->info("Connection Reestablishment received\n");
-      rrc_log->console("Reestablishment OK\n");
       transaction_id = dl_ccch_msg.msg.rrc_con_reest.rrc_transaction_id;
       handle_con_reest(&dl_ccch_msg.msg.rrc_con_reest);
       break;
@@ -1342,9 +1359,11 @@ void rrc::apply_sib2_configs(LIBLTE_RRC_SYS_INFO_BLOCK_TYPE_2_STRUCT *sib2) {
                 liblte_rrc_srs_subfr_config_num[sib2->rr_config_common_sib.srs_ul_cnfg.subfr_cnfg],
                 sib2->rr_config_common_sib.srs_ul_cnfg.ack_nack_simul_tx ? "yes" : "no");
 
+  mac_timers->timer_get(t300)->set(this, liblte_rrc_t300_num[sib2->ue_timers_and_constants.t300]);
   mac_timers->timer_get(t301)->set(this, liblte_rrc_t301_num[sib2->ue_timers_and_constants.t301]);
   mac_timers->timer_get(t310)->set(this, liblte_rrc_t310_num[sib2->ue_timers_and_constants.t310]);
   mac_timers->timer_get(t311)->set(this, liblte_rrc_t311_num[sib2->ue_timers_and_constants.t311]);
+
   N310 = liblte_rrc_n310_num[sib2->ue_timers_and_constants.n310];
   N311 = liblte_rrc_n311_num[sib2->ue_timers_and_constants.n311];
 
@@ -1581,13 +1600,50 @@ void rrc::apply_rr_config_dedicated(LIBLTE_RRC_RR_CONFIG_DEDICATED_STRUCT *cnfg)
   }
 }
 
+// 5.3.3.4
 void rrc::handle_con_setup(LIBLTE_RRC_CONNECTION_SETUP_STRUCT *setup) {
+  rrc_log->info("Connection Setup received\n");
+
   // Apply the Radio Resource configuration
   apply_rr_config_dedicated(&setup->rr_cnfg);
+
+  // stop timers
+  mac_timers->timer_get(t300)->stop();
+
+  // enter RRC CONNECTED
+  state = RRC_STATE_CONNECTED;
+
+  rrc_log->info("Notifying NAS of connection setup\n");
+  nas->notify_connection_setup();
+
+}
+
+// 5.3.3.8
+void rrc::handle_con_rej(LIBLTE_RRC_CONNECTION_REJECT_STRUCT *reject) {
+  rrc_log->info("Connection Reject received. Wait time: %d s\n",
+                dl_ccch_msg.msg.rrc_con_rej.wait_time);
+
+  rrc_log->console("Received Connection Reject. S1 link may not be active at the eNodeB\n");
+
+  mac_timers->timer_get(t300)->stop();
+  mac->reset();
+  set_mac_default();
+
+  mac_timers->timer_get(t302)->set(this, dl_ccch_msg.msg.rrc_con_rej.wait_time*1000);
+  mac_timers->timer_get(t302)->run();
+
+  nas->notify_connection_failure();
+  nas->network_barring_state(true);
+
+  state = RRC_STATE_IDLE;
 }
 
 /* Reception of RRCConnectionReestablishment by the UE 5.3.7.5 */
 void rrc::handle_con_reest(LIBLTE_RRC_CONNECTION_REESTABLISHMENT_STRUCT *setup) {
+  rrc_log->info("Connection Reestablishment received\n");
+  rrc_log->console("Reestablishment OK\n");
+
+
   mac_timers->timer_get(t301)->stop();
 
   // TODO: Restablish DRB1. Not done because never was suspended