fix undelivered PDCP SNs buffers in RLC AM to handle SN=-1 case

lib/include/srslte/upper/rlc_am_lte.h

@@ -123,33 +123,39 @@ private:
 
 struct buffered_pdcp_pdu_list {
 public:
-  const static size_t max_pdcp_sn = 262144;
-
-  void resize(size_t size);
+  explicit buffered_pdcp_pdu_list();
   void clear();
 
   void add_pdcp_sdu(uint32_t sn)
   {
     assert(not has_pdcp_sn(sn));
-    buffered_pdus[sn].sn = sn;
+    uint32_t sn_idx          = get_idx(sn);
+    buffered_pdus[sn_idx].sn = sn_idx;
     count++;
   }
   void clear_pdcp_sdu(uint32_t sn)
   {
-    buffered_pdus[sn].rlc_sn_info_list.clear();
-    buffered_pdus[sn].sn = -1;
+    uint32_t sn_idx = get_idx(sn);
+    buffered_pdus[sn_idx].rlc_sn_info_list.clear();
+    buffered_pdus[sn_idx].sn = -1;
     count--;
   }
 
-  pdcp_sdu_info_t& operator[](size_t sn)
+  pdcp_sdu_info_t& operator[](uint32_t sn)
   {
     assert(has_pdcp_sn(sn));
-    return buffered_pdus[sn];
+    uint32_t sn_idx = get_idx(sn);
+    return buffered_pdus[sn_idx];
   }
-  bool     has_pdcp_sn(uint32_t pdcp_sn) const { return buffered_pdus[pdcp_sn].sn < max_pdcp_sn; }
+  bool     has_pdcp_sn(uint32_t pdcp_sn) const { return buffered_pdus[get_idx(pdcp_sn)].sn < max_pdcp_sn; }
   uint32_t nof_sdus() const { return count; }
 
 private:
+  // TODO: Set size based on PDCP config
+  const static size_t max_pdcp_sn = 262143;
+
+  uint32_t get_idx(uint32_t sn) const { return std::min(sn, static_cast<uint32_t>(buffered_pdus.size() - 1)); }
+
   std::vector<pdcp_sdu_info_t> buffered_pdus;
   uint32_t                     count = 0;
 };

lib/src/upper/rlc_am_lte.cc

@@ -189,9 +189,6 @@ bool rlc_am_lte::rlc_am_lte_tx::configure(const rlc_config_t& cfg_)
   // TODO: add config checks
   cfg = cfg_.am;
 
-  // TODO: Set size based on PDCP config
-  undelivered_sdu_info_queue.resize(buffered_pdcp_pdu_list::max_pdcp_sn);
-
   // check timers
   if (not poll_retx_timer.is_valid() or not status_prohibit_timer.is_valid()) {
     logger.error("Configuring RLC AM TX: timers not configured");
@@ -1093,11 +1090,10 @@ void rlc_am_lte::rlc_am_lte_tx::handle_control_pdu(uint8_t* payload, uint32_t no
     // Remove all SDUs that were fully acked
     for (uint32_t acked_pdcp_sn : notify_info_vec) {
       logger.debug("Erasing SDU info: PDCP_SN=%d", acked_pdcp_sn);
-      if (undelivered_sdu_info_queue.has_pdcp_sn(acked_pdcp_sn)) {
-        undelivered_sdu_info_queue.clear_pdcp_sdu(acked_pdcp_sn);
-      } else {
+      if (not undelivered_sdu_info_queue.has_pdcp_sn(acked_pdcp_sn)) {
         logger.error("Could not find info to erase: SN=%d", acked_pdcp_sn);
       }
+      undelivered_sdu_info_queue.clear_pdcp_sdu(acked_pdcp_sn);
     }
   }
 
@@ -2017,11 +2013,9 @@ void rlc_am_lte::rlc_am_lte_rx::debug_state()
   logger.debug("%s vr_r = %d, vr_mr = %d, vr_x = %d, vr_ms = %d, vr_h = %d", RB_NAME, vr_r, vr_mr, vr_x, vr_ms, vr_h);
 }
 
-void buffered_pdcp_pdu_list::resize(size_t size)
+buffered_pdcp_pdu_list::buffered_pdcp_pdu_list() : buffered_pdus(max_pdcp_sn + 2)
 {
-  size_t old_size = buffered_pdus.size();
-  buffered_pdus.resize(size);
-  for (size_t i = old_size; i < buffered_pdus.size(); ++i) {
+  for (size_t i = 0; i < buffered_pdus.size(); ++i) {
     buffered_pdus[i].sn = -1;
     buffered_pdus[i].rlc_sn_info_list.reserve(5);
   }