Continue to add discard_sdu to RLC interfaces.

lib/include/srslte/interfaces/enb_interfaces.h

@@ -179,6 +179,7 @@ public:
   /* PDCP calls RLC to push an RLC SDU. SDU gets placed into the RLC buffer and MAC pulls
    * RLC PDUs according to TB size. */
   virtual void write_sdu(uint16_t rnti, uint32_t lcid, srslte::unique_byte_buffer_t sdu) = 0;
+  virtual void discard_sdu(uint16_t rnti, uint32_t lcid, uint32_t sn)                    = 0;
   virtual bool rb_is_um(uint16_t rnti, uint32_t lcid)                                    = 0;
 };
 
@@ -299,7 +300,8 @@ public:
                           LIBLTE_S1AP_RRC_ESTABLISHMENT_CAUSE_ENUM cause,
                           srslte::unique_byte_buffer_t             pdu,
                           uint32_t                                 m_tmsi,
-                          uint8_t                                  mmec)                                                                           = 0;
+                          uint8_t                                  mmec) = 0;
+
   virtual void write_pdu(uint16_t rnti, srslte::unique_byte_buffer_t pdu)                                         = 0;
   virtual bool user_exists(uint16_t rnti)                                                                         = 0;
   virtual bool user_release(uint16_t rnti, LIBLTE_S1AP_CAUSERADIONETWORK_ENUM cause_radio)                        = 0;

lib/include/srslte/interfaces/ue_interfaces.h

@@ -287,7 +287,7 @@ public:
   /* PDCP calls RLC to push an RLC SDU. SDU gets placed into the RLC buffer and MAC pulls
    * RLC PDUs according to TB size. */
   virtual void write_sdu(uint32_t lcid, srslte::unique_byte_buffer_t sdu, bool blocking = true) = 0;
-  virtual void discard_sdu(uint32_t discard_sn)                                                 = 0;
+  virtual void discard_sdu(uint32_t lcid, uint32_t discard_sn)                                  = 0;
   virtual bool rb_is_um(uint32_t lcid)                                                          = 0;
 };
 

lib/include/srslte/upper/rlc.h

@@ -37,10 +37,7 @@ namespace srslte {
  * Single interface for RLC layer - contains separate RLC entities for
  * each bearer.
  ***************************************************************************/
-class rlc
+class rlc : public srsue::rlc_interface_mac, public srsue::rlc_interface_pdcp, public srsue::rlc_interface_rrc
-    :public srsue::rlc_interface_mac
-    ,public srsue::rlc_interface_pdcp
-    ,public srsue::rlc_interface_rrc
 {
 public:
   rlc(log* rlc_log_);
@@ -57,6 +54,7 @@ public:
   void write_sdu(uint32_t lcid, unique_byte_buffer_t sdu, bool blocking = true);
   void write_sdu_mch(uint32_t lcid, unique_byte_buffer_t sdu);
   bool rb_is_um(uint32_t lcid);
+  void discard_sdu(uint32_t lcid, uint32_t discard_sn);
 
   // MAC interface
   bool     has_data(const uint32_t lcid);

lib/include/srslte/upper/rlc_common.h

@@ -248,11 +248,11 @@ public:
     }
   }
 
-  virtual rlc_mode_t    get_mode() = 0;
+  virtual rlc_mode_t get_mode()   = 0;
-  virtual uint32_t      get_bearer() = 0;
+  virtual uint32_t   get_bearer() = 0;
 
   virtual rlc_bearer_metrics_t get_metrics()   = 0;
-  virtual void reset_metrics() = 0;
+  virtual void                 reset_metrics() = 0;
 
   // PDCP interface
   virtual void write_sdu(unique_byte_buffer_t sdu, bool blocking) = 0;

lib/src/upper/pdcp_entity_nr.cc

@@ -366,7 +366,7 @@ void pdcp_entity_nr::discard_callback::operator()(uint32_t timer_id)
   parent->log->debug("Discard timer expired for PDU with SN = %d\n", discard_sn);
 
   // Notify the RLC of the discard. It's the RLC to actually discard, if no segment was transmitted yet.
-  parent->rlc->discard_sdu(discard_sn);
+  parent->rlc->discard_sdu(parent->lcid, discard_sn);
   return;
 }
 

lib/src/upper/rlc.cc

@@ -235,6 +235,17 @@ bool rlc::rb_is_um(uint32_t lcid)
   return ret;
 }
 
+void rlc::discard_sdu(uint32_t lcid, uint32_t discard_sn)
+{
+  pthread_rwlock_rdlock(&rwlock);
+  if (valid_lcid(lcid)) {
+    rlc_array.at(lcid)->discard_sdu(discard_sn);
+  } else {
+    rlc_log->warning("RLC LCID %d doesn't exist. Ignoring discard SDU\n", lcid);
+  }
+  pthread_rwlock_unlock(&rwlock);
+}
+
 /*******************************************************************************
   MAC interface
 *******************************************************************************/

lib/src/upper/rlc_um_base.cc

@@ -270,6 +270,11 @@ void rlc_um_base::rlc_um_base_tx::try_write_sdu(unique_byte_buffer_t sdu)
   }
 }
 
+void rlc_um_base::rlc_um_base_tx::discard_sdu(uint32_t discard_sn)
+{
+  log->warning("RLC UM: Discard SDU not implemented yet.\n");
+}
+
 int rlc_um_base::rlc_um_base_tx::build_data_pdu(uint8_t* payload, uint32_t nof_bytes)
 {
   unique_byte_buffer_t pdu;

lib/test/upper/pdcp_nr_test.h

@@ -86,8 +86,14 @@ public:
     last_pdcp_pdu.swap(sdu);
     rx_count++;
   }
+  void discard_sdu(uint32_t lcid, uint32_t discard_sn)
+  {
+    log->info("Notifing RLC to discard SDU (SN=%" PRIu32 ")\n", discard_sn);
+    discard_count++;
+  }
 
-  uint64_t rx_count = 0;
+  uint64_t rx_count      = 0;
+  uint64_t discard_count = 0;
 
 private:
   srslte::log*                 log;

srsenb/hdr/stack/upper/pdcp.h

@@ -66,7 +66,7 @@ private:
     srsenb::rlc_interface_pdcp* rlc;
     // rlc_interface_pdcp
     void write_sdu(uint32_t lcid, srslte::unique_byte_buffer_t sdu, bool blocking);
-    void discard_sdu(uint32_t discard_sn);
+    void discard_sdu(uint32_t lcid, uint32_t discard_sn);
     bool rb_is_um(uint32_t lcid);
   };
 

srsenb/hdr/stack/upper/rlc.h

@@ -56,9 +56,10 @@ public:
 
   // rlc_interface_pdcp
   void        write_sdu(uint16_t rnti, uint32_t lcid, srslte::unique_byte_buffer_t sdu);
-  bool rb_is_um(uint16_t rnti, uint32_t lcid);
+  void        discard_sdu(uint16_t rnti, uint32_t lcid, uint32_t discard_sn);
+  bool        rb_is_um(uint16_t rnti, uint32_t lcid);
   std::string get_rb_name(uint32_t lcid);
-  
+
   // rlc_interface_mac
   int  read_pdu(uint16_t rnti, uint32_t lcid, uint8_t *payload, uint32_t nof_bytes);
   void read_pdu_bcch_dlsch(uint32_t sib_index, uint8_t *payload);

srsenb/src/stack/upper/pdcp.cc

@@ -170,6 +170,11 @@ void pdcp::user_interface_rlc::write_sdu(uint32_t lcid, srslte::unique_byte_buff
   rlc->write_sdu(rnti, lcid, std::move(sdu));
 }
 
+void pdcp::user_interface_rlc::discard_sdu(uint32_t lcid, uint32_t discard_sn)
+{
+  rlc->discard_sdu(lcid, discard_sn);
+}
+
 bool pdcp::user_interface_rlc::rb_is_um(uint32_t lcid)
 {
   return rlc->rb_is_um(rnti, lcid);

srsenb/src/stack/upper/rlc.cc

@@ -198,6 +198,26 @@ void rlc::write_sdu(uint16_t rnti, uint32_t lcid, srslte::unique_byte_buffer_t s
   pthread_rwlock_unlock(&rwlock);
 }
 
+void rlc::discard_sdu(uint16_t rnti, uint32_t lcid, uint32_t discard_sn)
+{
+
+  uint32_t tx_queue;
+
+  pthread_rwlock_rdlock(&rwlock);
+  if (users.count(rnti)) {
+      users[rnti].rlc->discard_sdu(lcid, discard_sn);
+      tx_queue   = users[rnti].rlc->get_buffer_state(lcid);
+    }
+    // In the eNodeB, there is no polling for buffer state from the scheduler, thus 
+    // communicate buffer state every time a new SDU is discarded
+    
+    uint32_t retx_queue = 0; 
+    mac->rlc_buffer_state(rnti, lcid, tx_queue, retx_queue);
+    log_h->info("Buffer state: rnti=0x%x, lcid=%d, tx_queue=%d\n", rnti, lcid, tx_queue);
+  }
+  pthread_rwlock_unlock(&rwlock);
+}
+
 bool rlc::rb_is_um(uint16_t rnti, uint32_t lcid) {
   bool ret = false;
   pthread_rwlock_rdlock(&rwlock);

srsue/test/ttcn3/hdr/ttcn3_syssim.h

@@ -852,6 +852,8 @@ public:
     ue->new_tb(dl_grant, (const uint8_t*)mac_pdu_ptr);
   }
 
+  void discard_sdu(uint32_t lcid, uint32_t sn) {}
+
   bool rb_is_um(uint32_t lcid) { return false; }
 
   int set_as_security(const uint32_t                            lcid,