From 5b14a7d58508d5613c78b17228c2c695573936c3 Mon Sep 17 00:00:00 2001
From: Xavier Arteaga <xavier@softwareradiosystems.com>
Date: Wed, 29 Jan 2020 13:16:09 +0100
Subject: [PATCH] Implementation Tx RLC suspend

---
 lib/include/srslte/upper/rlc_common.h | 33 +++++++++++++++++++++++----
 lib/src/upper/rlc.cc                  |  2 +-
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/lib/include/srslte/upper/rlc_common.h b/lib/include/srslte/upper/rlc_common.h
index 065ec251c..29e3c355d 100644
--- a/lib/include/srslte/upper/rlc_common.h
+++ b/lib/include/srslte/upper/rlc_common.h
@@ -240,6 +240,11 @@ public:
       write_pdu(p.payload, p.nof_bytes);
       free(p.payload);
     }
+
+    unique_byte_buffer_t s;
+    while (tx_sdu_resume_queue.try_pop(&s)) {
+      write_sdu(std::move(s), false);
+    }
     suspended = false;
     return true;
   }
@@ -247,12 +252,21 @@ public:
   void write_pdu_s(uint8_t* payload, uint32_t nof_bytes)
   {
     if (suspended) {
-      queue_pdu(payload, nof_bytes);
+      queue_rx_pdu(payload, nof_bytes);
     } else {
       write_pdu(payload, nof_bytes);
     }
   }
 
+  void write_sdu_s(unique_byte_buffer_t sdu, bool blocking)
+  {
+    if (suspended) {
+      queue_tx_sdu(std::move(sdu));
+    } else {
+      write_sdu(std::move(sdu), blocking);
+    }
+  }
+
   virtual rlc_mode_t get_mode()   = 0;
   virtual uint32_t   get_bearer() = 0;
 
@@ -273,8 +287,8 @@ public:
 private:
   bool suspended = false;
 
-  // Enqueues the PDU in the resume queue
-  void queue_pdu(uint8_t* payload, uint32_t nof_bytes)
+  // Enqueues the Rx PDU in the resume queue
+  void queue_rx_pdu(uint8_t* payload, uint32_t nof_bytes)
   {
     pdu_t p     = {};
     p.nof_bytes = nof_bytes;
@@ -288,12 +302,23 @@ private:
     }
   }
 
+  // Enqueues the Tx SDU in the resume queue
+  void queue_tx_sdu(unique_byte_buffer_t sdu)
+  {
+    // Do not block ever
+    if (!tx_sdu_resume_queue.try_push(std::move(sdu)).first) {
+      fprintf(stderr, "Error dropping SDUs while bearer suspended. Queue should be unbounded\n");
+      return;
+    }
+  }
+
   typedef struct {
     uint8_t* payload;
     uint32_t nof_bytes;
   } pdu_t;
 
-  block_queue<pdu_t> rx_pdu_resume_queue;
+  block_queue<pdu_t>                rx_pdu_resume_queue;
+  block_queue<unique_byte_buffer_t> tx_sdu_resume_queue;
 };
 
 } // namespace srslte
diff --git a/lib/src/upper/rlc.cc b/lib/src/upper/rlc.cc
index 336a74913..f6aaf436c 100644
--- a/lib/src/upper/rlc.cc
+++ b/lib/src/upper/rlc.cc
@@ -201,7 +201,7 @@ void rlc::write_sdu(uint32_t lcid, unique_byte_buffer_t sdu, bool blocking)
 
   pthread_rwlock_rdlock(&rwlock);
   if (valid_lcid(lcid)) {
-    rlc_array.at(lcid)->write_sdu(std::move(sdu), blocking);
+    rlc_array.at(lcid)->write_sdu_s(std::move(sdu), blocking);
   } else {
     rlc_log->warning("RLC LCID %d doesn't exist. Deallocating SDU\n", lcid);
   }