enb: add MAC-NR PCAP

* use fixed filename until eNB stack layout is decided

lib/src/common/mac_pcap.cc

@@ -30,7 +30,7 @@ uint32_t mac_pcap::open(std::string filename_, uint32_t ue_id_)
     return SRSRAN_ERROR;
   }
 
-  // set DLT for selected RAT
+  // set UDP DLT
   dlt       = UDP_DLT;
   pcap_file = DLT_PCAP_Open(dlt, filename_.c_str());
   if (pcap_file == nullptr) {

srsenb/src/stack/enb_stack_lte.cc

@@ -166,6 +166,7 @@ int enb_stack_lte::init(const stack_args_t& args_, const rrc_cfg_t& rrc_cfg_)
   mac_args.fixed_dl_mcs  = 28;
   mac_args.fixed_ul_mcs  = 10;
   mac_args.pcap          = args.mac_pcap;
+  mac_args.pcap.filename = "/tmp/enb_mac_nr.pcap";
   if (mac_nr.init(mac_args, phy_nr, nullptr, &rlc_nr, &rrc_nr) != SRSRAN_SUCCESS) {
     stack_logger.error("Couldn't initialize MAC-NR");
     return SRSRAN_ERROR;

srsenb/src/stack/mac/nr/mac_nr.cc

@@ -27,7 +27,8 @@ namespace srsenb {
 mac_nr::mac_nr(srsran::task_sched_handle task_sched_) :
   logger(srslog::fetch_basic_logger("MAC-NR")),
   task_sched(task_sched_),
-  sched(srsenb::sched_nr_interface::sched_cfg_t{})
+  sched(srsenb::sched_nr_interface::sched_cfg_t{}),
+  bcch_bch_payload(srsran::make_byte_buffer())
 {
   stack_task_queue = task_sched.make_task_queue();
 }
@@ -61,11 +62,6 @@ int mac_nr::init(const mac_nr_args_t&    args_,
 
   detected_rachs.resize(cells_cfg.size());
 
-  bcch_bch_payload = srsran::make_byte_buffer();
-  if (bcch_bch_payload == nullptr) {
-    return SRSRAN_ERROR;
-  }
-
   logger.info("Started");
 
   started = true;
@@ -203,9 +199,6 @@ uint16_t mac_nr::add_ue(uint32_t enb_cc_idx)
     }
   } while (inserted_ue == nullptr);
 
-  // Set PCAP if available
-  // ..
-
   return rnti;
 }
 
@@ -283,6 +276,11 @@ int mac_nr::get_dl_sched(const srsran_slot_cfg_t& slot_cfg, dl_sched_t& dl_sched
           continue;
         }
         ue_db[rnti]->generate_pdu(tb_data, pdsch.sch.grant.tb->tbs / 8);
+
+        if (pcap != nullptr) {
+          uint32_t pid = 0; // TODO: get PID from PDCCH struct?
+          pcap->write_dl_crnti_nr(tb_data->msg, tb_data->N_bytes, rnti, pid, slot_cfg.idx);
+        }
       }
     }
   }