gtpu, feature - added the ability to configure gtpu indirect tunnel timeout value. This parameter is useful in the case that the end marker is not received

lib/include/srsran/interfaces/enb_gtpu_interfaces.h

@@ -18,6 +18,15 @@
 
 namespace srsenb {
 
+struct gtpu_args_t {
+  std::string gtp_bind_addr;
+  std::string mme_addr;
+  std::string embms_m1u_multiaddr;
+  std::string embms_m1u_if_addr;
+  bool        embms_enable                 = false;
+  uint32_t    indirect_tunnel_timeout_msec = 2000;
+};
+
 // GTPU interface for PDCP
 class gtpu_interface_pdcp
 {

srsenb/enb.conf.example

@@ -307,6 +307,7 @@ enable = false
 # nof_prealloc_ues:     Number of UE memory resources to preallocate during eNB initialization for faster UE creation (Default 8)
 # eea_pref_list:        Ordered preference list for the selection of encryption algorithm (EEA) (default: EEA0, EEA2, EEA1).
 # eia_pref_list:        Ordered preference list for the selection of integrity algorithm (EIA) (default: EIA2, EIA1, EIA0).
+# gtpu_tunnel_timeout:  Maximum time that GTPU takes to release indirect forwarding tunnel since the last received GTPU PDU.
 #
 #####################################################################
 [expert]
@@ -331,3 +332,4 @@ enable = false
 #nof_prealloc_ues     = 8
 #eea_pref_list = EEA0, EEA2, EEA1
 #eia_pref_list = EIA2, EIA1, EIA0
+#gtpu_tunnel_timeout = 2000

srsenb/hdr/enb.h

@@ -95,6 +95,7 @@ struct general_args_t {
   std::string eea_pref_list;
   uint32_t    max_mac_dl_kos;
   uint32_t    max_mac_ul_kos;
+  uint32_t    gtpu_indirect_tunnel_timeout;
 };
 
 struct all_args_t {

srsenb/hdr/stack/enb_stack_base.h

@@ -70,6 +70,7 @@ typedef struct {
 typedef struct {
   std::string      type;
   uint32_t         sync_queue_size; // Max allowed difference between PHY and Stack clocks (in TTI)
+  uint32_t         gtpu_indirect_tunnel_timeout_msec;
   mac_args_t       mac;
   s1ap_args_t      s1ap;
   pcap_args_t      mac_pcap;

srsenb/hdr/stack/upper/gtpu.h

@@ -90,7 +90,7 @@ public:
   using ue_lcid_tunnel_list = srsran::bounded_vector<lcid_tunnel, MAX_TUNNELS_PER_UE>;
 
   explicit gtpu_tunnel_manager(srsran::task_sched_handle task_sched_, srslog::basic_logger& logger);
-  void init(pdcp_interface_gtpu* pdcp_);
+  void init(const gtpu_args_t& gtpu_args, pdcp_interface_gtpu* pdcp_);
 
   bool                      has_teid(uint32_t teid) const { return tunnels.contains(teid); }
   const tunnel*             find_tunnel(uint32_t teid);
@@ -116,6 +116,7 @@ private:
   using tunnel_ctxt_it = typename tunnel_list_t::iterator;
 
   srsran::task_sched_handle task_sched;
+  const gtpu_args_t*        gtpu_args = nullptr;
   pdcp_interface_gtpu*      pdcp      = nullptr;
   srslog::basic_logger&     logger;
 
@@ -134,12 +135,7 @@ public:
                 srsran::socket_manager_itf* rx_socket_handler_);
   ~gtpu();
 
-  int  init(std::string          gtp_bind_addr_,
-            std::string          mme_addr_,
-            std::string          m1u_multiaddr_,
-            std::string          m1u_if_addr_,
-            pdcp_interface_gtpu* pdcp_,
-            bool                 enable_mbsfn = false);
+  int  init(const gtpu_args_t& gtpu_args, pdcp_interface_gtpu* pdcp_);
   void stop();
 
   // gtpu_interface_rrc
@@ -168,7 +164,7 @@ private:
   srsran::socket_manager_itf* rx_socket_handler = nullptr;
   srsran::task_queue_handle   gtpu_queue;
 
-  bool                         enable_mbsfn = false;
+  gtpu_args_t                  args;
   std::string                  gtp_bind_addr;
   std::string                  mme_addr;
   srsenb::pdcp_interface_gtpu* pdcp = nullptr;

srsenb/src/main.cc

@@ -217,6 +217,7 @@ void parse_args(all_args_t* args, int argc, char* argv[])
     ("expert.nof_prealloc_ues", bpo::value<uint32_t>(&args->stack.mac.nof_prealloc_ues)->default_value(8), "Number of UE resources to preallocate during eNB initialization")
     ("expert.max_mac_dl_kos", bpo::value<uint32_t>(&args->general.max_mac_dl_kos)->default_value(100), "Maximum number of consecutive KOs in DL before triggering the UE's release")
     ("expert.max_mac_ul_kos", bpo::value<uint32_t>(&args->general.max_mac_ul_kos)->default_value(100), "Maximum number of consecutive KOs in UL before triggering the UE's release")
+    ("expert.gtpu_tunnel_timeout", bpo::value<uint32_t>(&args->stack.gtpu_indirect_tunnel_timeout_msec)->default_value(2000), "Maximum time that GTPU takes to release indirect forwarding tunnel since the last received GTPU PDU.")
 
 
     // eMBMS section

srsenb/src/stack/enb_stack_lte.cc

@@ -133,12 +133,15 @@ int enb_stack_lte::init(const stack_args_t& args_, const rrc_cfg_t& rrc_cfg_)
     stack_logger.error("Couldn't initialize S1AP");
     return SRSRAN_ERROR;
   }
-  if (gtpu.init(args.s1ap.gtp_bind_addr,
-                args.s1ap.mme_addr,
-                args.embms.m1u_multiaddr,
-                args.embms.m1u_if_addr,
-                &pdcp,
-                args.embms.enable)) {
+
+  gtpu_args_t gtpu_args;
+  gtpu_args.embms_enable                 = args.embms.enable;
+  gtpu_args.embms_m1u_multiaddr          = args.embms.m1u_multiaddr;
+  gtpu_args.embms_m1u_if_addr            = args.embms.m1u_if_addr;
+  gtpu_args.mme_addr                     = args.s1ap.mme_addr;
+  gtpu_args.gtp_bind_addr                = args.s1ap.gtp_bind_addr;
+  gtpu_args.indirect_tunnel_timeout_msec = args.gtpu_indirect_tunnel_timeout_msec;
+  if (gtpu.init(gtpu_args, &pdcp) != SRSRAN_SUCCESS) {
     stack_logger.error("Couldn't initialize GTPU");
     return SRSRAN_ERROR;
   }

srsenb/src/stack/upper/gtpu.cc

@@ -36,8 +36,9 @@ gtpu_tunnel_manager::gtpu_tunnel_manager(srsran::task_sched_handle task_sched_,
   logger(logger), task_sched(task_sched_), tunnels(1)
 {}
 
-void gtpu_tunnel_manager::init(pdcp_interface_gtpu* pdcp_)
+void gtpu_tunnel_manager::init(const gtpu_args_t& args, pdcp_interface_gtpu* pdcp_)
 {
+  gtpu_args = &args;
   pdcp      = pdcp_;
 }
 
@@ -239,10 +240,13 @@ void gtpu_tunnel_manager::set_tunnel_priority(uint32_t before_teid, uint32_t aft
     }
   };
 
-  // Schedule auto-removal of this indirect tunnel
+  // Schedule auto-removal of the indirect tunnel in case the End Marker is not received
+  // TS 36.300 - On detection of the "end marker", the target eNB may also initiate the release of the data forwarding
+  //             resource. However, the release of the data forwarding resource is implementation dependent and could
+  //             also be based on other mechanisms (e.g. timer-based mechanism).
   before_tun.rx_timer = task_sched.get_unique_timer();
-  before_tun.rx_timer.set(500, [this, before_teid](uint32_t tid) {
-    // This will self-destruct the callback object
+  before_tun.rx_timer.set(gtpu_args->indirect_tunnel_timeout_msec, [this, before_teid](uint32_t tid) {
+    // Note: This will self-destruct the callback object
     remove_tunnel(before_teid);
   });
   before_tun.rx_timer.run();
@@ -323,18 +327,14 @@ gtpu::~gtpu()
   stop();
 }
 
-int gtpu::init(std::string                  gtp_bind_addr_,
-               std::string                  mme_addr_,
-               std::string                  m1u_multiaddr_,
-               std::string                  m1u_if_addr_,
-               srsenb::pdcp_interface_gtpu* pdcp_,
-               bool                         enable_mbsfn_)
+int gtpu::init(const gtpu_args_t& gtpu_args, pdcp_interface_gtpu* pdcp_)
 {
+  args          = gtpu_args;
   pdcp          = pdcp_;
-  gtp_bind_addr = gtp_bind_addr_;
-  mme_addr      = mme_addr_;
+  gtp_bind_addr = gtpu_args.gtp_bind_addr;
+  mme_addr      = gtpu_args.mme_addr;
 
-  tunnels.init(pdcp);
+  tunnels.init(args, pdcp);
 
   char errbuf[128] = {};
 
@@ -374,9 +374,8 @@ int gtpu::init(std::string                  gtp_bind_addr_,
   rx_socket_handler->add_socket_handler(fd, srsran::make_sdu_handler(logger, gtpu_queue, rx_callback));
 
   // Start MCH socket if enabled
-  enable_mbsfn = enable_mbsfn_;
-  if (enable_mbsfn) {
-    if (not m1u.init(m1u_multiaddr_, m1u_if_addr_)) {
+  if (args.embms_enable) {
+    if (not m1u.init(args.embms_m1u_multiaddr, args.embms_m1u_if_addr)) {
       return SRSRAN_ERROR;
     }
   }

srsenb/test/upper/gtpu_test.cc

@@ -232,8 +232,12 @@ int test_gtpu_direct_tunneling(tunnel_test_event event)
   dummy_socket_manager   senb_rx_sockets, tenb_rx_sockets;
   srsenb::gtpu senb_gtpu(&task_sched, logger1, &senb_rx_sockets), tenb_gtpu(&task_sched, logger2, &tenb_rx_sockets);
   pdcp_tester  senb_pdcp, tenb_pdcp;
-  senb_gtpu.init(senb_addr_str, sgw_addr_str, "", "", &senb_pdcp, false);
-  tenb_gtpu.init(tenb_addr_str, sgw_addr_str, "", "", &tenb_pdcp, false);
+  gtpu_args_t  gtpu_args;
+  gtpu_args.gtp_bind_addr = senb_addr_str;
+  gtpu_args.mme_addr      = sgw_addr_str;
+  senb_gtpu.init(gtpu_args, &senb_pdcp);
+  gtpu_args.gtp_bind_addr = tenb_addr_str;
+  tenb_gtpu.init(gtpu_args, &tenb_pdcp);
 
   // create tunnels MME-SeNB and MME-TeNB
   uint32_t senb_teid_in = senb_gtpu.add_bearer(rnti, drb1, sgw_addr, sgw_teidout1).value();