du,du_high: add option to set external address of f1u interface

Author: FabianEckermann

apps/du/du.cpp

@@ -282,8 +282,8 @@ int main(int argc, char** argv)
       du_f1u_gw_config,
       *epoll_broker,
       workers.get_du_high_executor_mapper(0).ue_mapper().mac_ul_pdu_executor(to_du_ue_index(0)));
-  std::unique_ptr<srs_du::f1u_du_udp_gateway> du_f1u_conn =
-      srs_du::create_split_f1u_gw({du_f1u_gw.get(), du_f1u_gtpu_demux.get(), *du_pcaps.f1u, GTPU_PORT});
+  std::unique_ptr<srs_du::f1u_du_udp_gateway> du_f1u_conn = srs_du::create_split_f1u_gw(
+      {du_f1u_gw.get(), du_f1u_gtpu_demux.get(), *du_pcaps.f1u, GTPU_PORT, du_cfg.nru_cfg.ext_addr});
 
   // Set up the JSON log channel used by metrics.
   srslog::sink& json_sink =

apps/du/du_appconfig.h

@@ -31,6 +31,7 @@ struct f1ap_appconfig {
 struct nru_appconfig {
   unsigned    pdu_queue_size = 2048;
   std::string bind_address   = "127.0.10.2";
+  std::string ext_addr       = "auto"; // External address advertised by the F1-U interface
   float       pool_threshold = 0.9;
 };
 

apps/du/du_appconfig_cli11_schema.cpp

@@ -236,6 +236,9 @@ static void configure_cli11_f1u_args(CLI::App& app, srs_du::nru_appconfig& f1u_p
   app.add_option(
          "--bind_addr", f1u_params.bind_address, "DU F1-U bind address. If left empty, implicit bind is performed")
       ->capture_default_str();
+  app.add_option("--ext_addr",
+                 f1u_params.ext_addr,
+                 "External IP address that is advertised to receive F1-U packets from the CU-UP");
   app.add_option(
          "--pool_threshold", f1u_params.pool_threshold, "Pool occupancy threshold after which packets are dropped")
       ->capture_default_str();

apps/du/du_appconfig_yaml_writer.cpp

@@ -81,6 +81,7 @@ static void fill_du_appconfig_nru_section(YAML::Node node, const srs_du::nru_app
 {
   node["queue_size"] = config.pdu_queue_size;
   node["bind_addr"]  = config.bind_address;
+  node["ext_addr"]   = config.ext_addr;
 }
 
 static void fill_du_appconfig_f1ap_section(YAML::Node node, const srs_du::f1ap_appconfig& config)

include/srsran/f1u/du/split_connector/f1u_split_connector_factory.h

@@ -24,6 +24,7 @@ struct f1u_du_split_gateway_creation_msg {
   gtpu_demux*             demux;
   dlt_pcap&               gtpu_pcap;
   uint16_t                peer_port;
+  std::string             f1u_ext_addr = "auto";
 };
 
 std::unique_ptr<f1u_du_udp_gateway> create_split_f1u_gw(f1u_du_split_gateway_creation_msg msg);

lib/f1u/du/split_connector/f1u_split_connector.cpp

@@ -78,8 +78,13 @@ void f1u_split_connector::remove_du_bearer(const up_transport_layer_info& dl_up_
 expected<std::string> f1u_split_connector::get_du_bind_address(gnb_du_id_t gnb_du_id) const
 {
   std::string ip_address;
-  if (not udp_session->get_bind_address(ip_address)) {
-    return make_unexpected(default_error_t{});
+
+  if (f1u_ext_addr == "auto") {
+    if (not udp_session->get_bind_address(ip_address)) {
+      return make_unexpected(default_error_t{});
+    }
+  } else {
+    ip_address = f1u_ext_addr;
   }
   return ip_address;
 }

lib/f1u/du/split_connector/f1u_split_connector.h

@@ -171,12 +171,14 @@ class f1u_split_connector final : public f1u_du_udp_gateway
   f1u_split_connector(srs_cu_up::ngu_gateway* udp_gw_,
                       gtpu_demux*             demux_,
                       dlt_pcap&               gtpu_pcap_,
-                      uint16_t                peer_port_ = GTPU_PORT) :
+                      uint16_t                peer_port_    = GTPU_PORT,
+                      std::string             f1u_ext_addr_ = "auto") :
     logger_du(srslog::fetch_basic_logger("DU-F1-U")),
     udp_gw(udp_gw_),
     demux(demux_),
     gtpu_pcap(gtpu_pcap_),
-    peer_port(peer_port_)
+    peer_port(peer_port_),
+    f1u_ext_addr(std::move(f1u_ext_addr_))
   {
     udp_session = udp_gw->create(gw_data_gtpu_demux_adapter);
     gw_data_gtpu_demux_adapter.connect_gtpu_demux(*demux);
@@ -211,7 +213,8 @@ class f1u_split_connector final : public f1u_du_udp_gateway
   network_gateway_data_gtpu_demux_adapter         gw_data_gtpu_demux_adapter;
   dlt_pcap&                                       gtpu_pcap;
 
-  uint16_t peer_port;
+  uint16_t    peer_port;
+  std::string f1u_ext_addr = "auto"; // External address advertised by the F1-U interface
 };
 
 } // namespace srsran::srs_du

lib/f1u/du/split_connector/f1u_split_connector_factory.cpp

@@ -17,5 +17,5 @@ using namespace srs_du;
 
 std::unique_ptr<f1u_du_udp_gateway> srsran::srs_du::create_split_f1u_gw(f1u_du_split_gateway_creation_msg msg)
 {
-  return std::make_unique<f1u_split_connector>(msg.udp_gw, msg.demux, msg.gtpu_pcap, msg.peer_port);
+  return std::make_unique<f1u_split_connector>(msg.udp_gw, msg.demux, msg.gtpu_pcap, msg.peer_port, msg.f1u_ext_addr);
 }

tests/unittests/du_manager/du_manager_test_helpers.h

@@ -207,9 +207,19 @@ class f1u_gateway_dummy : public f1u_du_gateway
     f1u_bearers.erase(bearer_it);
   }
 
-  expected<std::string> get_du_bind_address(gnb_du_id_t du_index) const override { return std::string("127.0.0.1"); }
+  expected<std::string> get_du_bind_address(gnb_du_id_t du_index) const override
+  {
+    if (f1u_ext_addr == "auto") {
+      return std::string("127.0.0.1");
+    }
+    return f1u_ext_addr;
+  }
 
   std::map<up_transport_layer_info, std::map<up_transport_layer_info, f1u_gw_bearer_dummy*>> f1u_bearers;
+
+  void set_f1u_ext_addr(const std::string& addr) { f1u_ext_addr = addr; }
+
+  std::string f1u_ext_addr = "auto";
 };
 
 class mac_test_dummy : public mac_cell_manager,