pdcp: adding basic test to check if control PDUs are handled correctly

use a 3 B long status PDU to check if its dropped from the rx'ing entity

lib/test/upper/pdcp_lte_test_rx.cc

@@ -62,15 +62,20 @@ int test_rx(std::vector<pdcp_test_event_t>      events,
   // Test if the number of RX packets
   if (rb_type == srslte::PDCP_RB_IS_DRB) {
     TESTASSERT(gw_rx->rx_count == n_sdus_exp);
+    if (n_sdus_exp > 0) {
       srslte::unique_byte_buffer_t sdu_act = allocate_unique_buffer(*pool);
       gw_rx->get_last_pdu(sdu_act);
       TESTASSERT(compare_two_packets(sdu_exp, sdu_act) == 0);
+    }
+
   } else {
     TESTASSERT(rrc_rx->rx_count == n_sdus_exp);
+    if (n_sdus_exp > 0) {
       srslte::unique_byte_buffer_t sdu_act = allocate_unique_buffer(*pool);
       rrc_rx->get_last_pdu(sdu_act);
       TESTASSERT(compare_two_packets(sdu_exp, sdu_act) == 0);
     }
+  }
   return 0;
 }
 
@@ -154,6 +159,36 @@ int test_rx_all(srslte::byte_buffer_pool* pool, srslte::log_ref log)
   return SRSLTE_SUCCESS;
 }
 
+// Basic test to verify the correct handling of PDCP status PDUs on DRBs
+// As long as we don't implement status reporting, the PDU shall be dropped
+int test_rx_control_pdu(srslte::byte_buffer_pool* pool, srslte::log_ref log)
+{
+  const uint8_t pdcp_status_report_long[] = {0x0a, 0xc9, 0x3c};
+
+  std::vector<pdcp_test_event_t> pdu_vec;
+
+  pdcp_test_event_t event;
+  event.pkt = allocate_unique_buffer(*pool);
+  memcpy(event.pkt->msg, pdcp_status_report_long, sizeof(pdcp_status_report_long));
+  event.pkt->N_bytes = sizeof(pdcp_status_report_long);
+  pdu_vec.push_back(std::move(event));
+
+  srslte::unique_byte_buffer_t tst_sdu1 = allocate_unique_buffer(*pool);
+
+  srslte::pdcp_lte_state_t test_init_state = {
+      .next_pdcp_tx_sn = 0, .tx_hfn = 0, .rx_hfn = 0, .next_pdcp_rx_sn = 32, .last_submitted_pdcp_rx_sn = 31};
+  TESTASSERT(test_rx(std::move(pdu_vec),
+                     test_init_state,
+                     srslte::PDCP_SN_LEN_12,
+                     srslte::PDCP_RB_IS_DRB,
+                     0,
+                     tst_sdu1,
+                     pool,
+                     log) == 0);
+
+  return SRSLTE_SUCCESS;
+}
+
 // Setup all tests
 int run_all_tests(srslte::byte_buffer_pool* pool)
 {
@@ -163,6 +198,8 @@ int run_all_tests(srslte::byte_buffer_pool* pool)
   log->set_hex_limit(128);
 
   TESTASSERT(test_rx_all(pool, log) == 0);
+  TESTASSERT(test_rx_control_pdu(pool, log) == 0);
+
   return 0;
 }