From 7ccc7d1d208a92b779fde8abaeb58f67a2ba95ac Mon Sep 17 00:00:00 2001
From: Pedro Alvarez <pedro.alvarez@softwareradiosystems.com>
Date: Mon, 25 Nov 2019 12:04:31 +0000
Subject: [PATCH] Starting to notify RLC upon PDCP discard (NR)

---
 lib/include/srslte/upper/pdcp_entity_nr.h | 20 +++++++++++++++++++-
 lib/src/upper/pdcp_entity_nr.cc           | 19 ++++++++++++++++---
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/lib/include/srslte/upper/pdcp_entity_nr.h b/lib/include/srslte/upper/pdcp_entity_nr.h
index b00f33b9c..3beb1c2ec 100644
--- a/lib/include/srslte/upper/pdcp_entity_nr.h
+++ b/lib/include/srslte/upper/pdcp_entity_nr.h
@@ -96,10 +96,12 @@ private:
   void pass_to_upper_layers(unique_byte_buffer_t pdu);
 
   // Reodering callback (t-Reordering)
-
   class reordering_callback;
   std::unique_ptr<reordering_callback> reordering_fnc;
 
+  // Discard callback (discardTimer)
+  class discard_callback;
+
   // COUNT overflow protection
   bool tx_overflow = false;
   bool rx_overflow = false;
@@ -119,6 +121,22 @@ private:
   pdcp_entity_nr* parent;
 };
 
+// Discard callback (discardTimer)
+class pdcp_entity_nr::discard_callback
+{
+public:
+  discard_callback(pdcp_entity_nr* parent_, uint32_t sn_)
+  {
+    parent     = parent_;
+    discard_sn = sn_;
+  };
+  void operator()(uint32_t timer_id);
+
+private:
+  pdcp_entity_nr* parent;
+  uint32_t        sn;
+};
+
 /*
  * Helpers
  */
diff --git a/lib/src/upper/pdcp_entity_nr.cc b/lib/src/upper/pdcp_entity_nr.cc
index 3bc8fe060..50e2c1a74 100644
--- a/lib/src/upper/pdcp_entity_nr.cc
+++ b/lib/src/upper/pdcp_entity_nr.cc
@@ -307,9 +307,6 @@ void pdcp_entity_nr::append_mac(const unique_byte_buffer_t& sdu, uint8_t* mac)
   sdu->N_bytes += 4;
 }
 
-/*
- * Reordering Helpers
- */
 // Deliver all consecutivly associated COUNTs.
 // Update RX_NEXT after submitting to higher layers
 void pdcp_entity_nr::deliver_all_consecutive_counts()
@@ -336,6 +333,9 @@ void pdcp_entity_nr::deliver_all_consecutive_counts()
   }
 }
 
+/*
+ * Reordering Timer Callback
+ */
 void pdcp_entity_nr::reordering_callback::operator()(uint32_t timer_id)
 {
   parent->log->debug("Reordering timer expired\n");
@@ -357,4 +357,17 @@ void pdcp_entity_nr::reordering_callback::operator()(uint32_t timer_id)
   }
   return;
 }
+
+/*
+ * Discard Timer Callback
+ */
+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);
+  return;
+}
+
 } // namespace srslte