e1ap: implement E1 SCTP Gateway unit test

Author: frankist

include/srsran/e1ap/gateways/e1_local_connector_factory.h

@@ -16,6 +16,7 @@
 namespace srsran {
 
 class dlt_pcap;
+class io_broker;
 
 class e1_local_connector : public srs_cu_up::e1_connection_client, public srs_cu_cp::e1_connection_server
 {};
@@ -29,4 +30,16 @@ struct e1_local_connector_config {
 /// E1AP PDUs or any socket send/recv.
 std::unique_ptr<e1_local_connector> create_e1_local_connector(const e1_local_connector_config& cfg);
 
+struct e1_local_sctp_connector_config {
+  /// PCAP writer for the E1AP messages.
+  dlt_pcap& pcap;
+  /// IO broker to handle the SCTP Rx data and notifications.
+  io_broker& broker;
+};
+
+/// Creates an E1 local connector using an SCTP socket as channel.
+///
+/// Note: This class is useful for testing.
+std::unique_ptr<e1_local_connector> create_e1_local_connector(const e1_local_sctp_connector_config& cfg);
+
 } // namespace srsran

include/srsran/gateways/sctp_network_gateway.h

@@ -18,6 +18,7 @@ namespace srsran {
 
 constexpr uint16_t NGAP_PPID  = 60; // NGAP PPID, see TS 38.412, section 7.
 constexpr uint16_t F1AP_PPID  = 62; // F1AP PPID, see TS 38.472, section 7.
+constexpr uint16_t E1AP_PPID  = 64; // E1AP PPID, see TS 37.482, section 7.
 constexpr uint16_t E2_CP_PPID = 70; // E2-CP PPID assigned by IANA
 constexpr uint16_t E2_UP_PPID = 71; // E2-UP PPID assigned by IANA
 constexpr uint16_t E2_DU_PPID = 72; // E2-DU PPID assigned by IANA

lib/e1ap/gateways/CMakeLists.txt

@@ -10,4 +10,4 @@ add_library(srsran_e1_gateway
         e1_local_connector_factory.cpp
         e1_network_client_factory.cpp
         e1_network_server_factory.cpp)
-target_link_libraries(srsran_e1_gateway srsran_support srsran_e1ap_common e1ap_asn1)
+target_link_libraries(srsran_e1_gateway srsran_support srsran_e1ap_common e1ap_asn1 srsran_pcap)

lib/e1ap/gateways/e1_local_connector_factory.cpp

@@ -11,6 +11,8 @@
 #include "srsran/e1ap/gateways/e1_local_connector_factory.h"
 #include "srsran/cu_cp/cu_cp_e1_handler.h"
 #include "srsran/e1ap/common/e1ap_message.h"
+#include "srsran/e1ap/gateways/e1_network_client_factory.h"
+#include "srsran/e1ap/gateways/e1_network_server_factory.h"
 #include "srsran/pcap/dlt_pcap.h"
 
 using namespace srsran;
@@ -87,9 +89,64 @@ class e1_local_connector_impl final : public e1_local_connector
   srs_cu_cp::cu_cp_e1_handler* cu_cp_e1_mng = nullptr;
 };
 
+/// Implementation of a CU-UP and CU-CP E1 SCTP-based gateway for the case that the DU and CU-CP are co-located.
+///
+/// Note: This class should only be used for testing purposes.
+class e1_sctp_connector_impl final : public e1_local_connector
+{
+public:
+  e1_sctp_connector_impl(const e1_local_sctp_connector_config& cfg) : broker(cfg.broker), pcap_writer(cfg.pcap)
+  {
+    // Create SCTP server.
+    sctp_network_gateway_config sctp;
+    sctp.if_name      = "E1";
+    sctp.ppid         = E1AP_PPID;
+    sctp.bind_address = "127.0.0.1";
+    // Use any bind port available.
+    sctp.bind_port = 0;
+    server         = create_e1_gateway_server(e1_cu_sctp_gateway_config{sctp, broker, pcap_writer});
+  }
+
+  void attach_cu_cp(srs_cu_cp::cu_cp_e1_handler& cu_e1_handler_) override
+  {
+    server->attach_cu_cp(cu_e1_handler_);
+
+    // Create SCTP client.
+    sctp_network_connector_config sctp_client;
+    sctp_client.if_name         = "E1";
+    sctp_client.dest_name       = "CU-CP";
+    sctp_client.connect_address = "127.0.0.1";
+    sctp_client.connect_port    = server->get_listen_port().value();
+    sctp_client.ppid            = E1AP_PPID;
+    // Note: We only need to save the PCAPs in one side of the connection.
+    client = create_e1_gateway_client(e1_du_sctp_gateway_config{sctp_client, broker, *null_pcap_writer});
+  }
+
+  std::optional<uint16_t> get_listen_port() const override { return server->get_listen_port(); }
+
+  std::unique_ptr<e1ap_message_notifier>
+  handle_cu_up_connection_request(std::unique_ptr<e1ap_message_notifier> cu_up_rx_pdu_notifier) override
+  {
+    // Connect client to server automatically.
+    return client->handle_cu_up_connection_request(std::move(cu_up_rx_pdu_notifier));
+  }
+
+private:
+  io_broker&                                       broker;
+  dlt_pcap&                                        pcap_writer;
+  std::unique_ptr<dlt_pcap>                        null_pcap_writer = create_null_dlt_pcap();
+  std::unique_ptr<srs_cu_cp::e1_connection_server> server;
+  std::unique_ptr<srs_cu_up::e1_connection_client> client;
+};
+
 } // namespace
 
 std::unique_ptr<e1_local_connector> srsran::create_e1_local_connector(const e1_local_connector_config& cfg)
 {
   return std::make_unique<e1_local_connector_impl>(cfg);
 }
+
+std::unique_ptr<e1_local_connector> srsran::create_e1_local_connector(const e1_local_sctp_connector_config& cfg)
+{
+  return std::make_unique<e1_sctp_connector_impl>(cfg);
+}

tests/unittests/e1ap/CMakeLists.txt

@@ -13,3 +13,4 @@ include_directories(../../..)
 add_subdirectory(common)
 add_subdirectory(cu_cp)
 add_subdirectory(cu_up)
+add_subdirectory(gateways)

tests/unittests/e1ap/gateways/CMakeLists.txt

@@ -0,0 +1,21 @@
+#
+# Copyright 2021-2024 Software Radio Systems Limited
+#
+# By using this file, you agree to the terms and conditions set
+# forth in the LICENSE file which can be found at the top level of
+# the distribution.
+#
+
+add_executable(e1_gateway_test e1_gateway_test.cpp)
+target_link_libraries(e1_gateway_test
+        srsran_e1_gateway
+        srsran_gateway
+        e1ap_test_helpers
+        srsran_e1ap_common
+        srsran_support
+        srsran_network
+        srslog
+        e1ap_asn1
+        gtest
+        gtest_main)
+add_test(e1_gateway_test e1_gateway_test)