enb,nr: fix GTPU handler to forward UL PDUs

lib/include/srsran/interfaces/enb_gtpu_interfaces.h

@@ -31,7 +31,8 @@ struct gtpu_args_t {
 class gtpu_interface_pdcp
 {
 public:
-  virtual void write_pdu(uint16_t rnti, uint32_t bearer_id, srsran::unique_byte_buffer_t pdu) = 0;
+  // PDCP will only know LCIDs, translation to EPS bearer id will be done by gtpu_pdcp_adapter
+  virtual void write_pdu(uint16_t rnti, uint32_t lcid, srsran::unique_byte_buffer_t pdu) = 0;
 };
 
 // GTPU interface for RRC

lib/include/srsran/interfaces/enb_x2_interfaces.h

@@ -10,6 +10,7 @@
  *
  */
 
+#include "srsran/interfaces/enb_gtpu_interfaces.h"
 #include "srsran/interfaces/enb_pdcp_interfaces.h"
 #include "srsran/interfaces/enb_rrc_interface_types.h"
 
@@ -93,7 +94,8 @@ public:
 class x2_interface : public rrc_nr_interface_rrc,
                      public rrc_eutra_interface_rrc_nr,
                      public stack_nr_interface_stack_eutra,
-                     public pdcp_interface_gtpu
+                     public pdcp_interface_gtpu, // allow GTPU to access PDCP in DL direction
+                     public gtpu_interface_pdcp  // allow PDCP to access GTPU in UL direction
 {};
 
 } // namespace srsenb

srsenb/hdr/stack/enb_stack_lte.h

@@ -119,6 +119,9 @@ public:
     rrc.sgnb_addition_complete(eutra_rnti, nr_rnti);
   }
 
+  // gtpu_interface_pdcp
+  void write_pdu(uint16_t rnti, uint32_t lcid, srsran::unique_byte_buffer_t pdu);
+
 private:
   static const int STACK_MAIN_THREAD_PRIO = 4;
   // thread loop

srsenb/hdr/x2_adapter.h

@@ -110,6 +110,15 @@ public:
     return nr_stack->get_buffered_pdus(rnti, lcid);
   }
 
+  // gtpu_interface_pdcp
+  void write_pdu(uint16_t rnti, uint32_t bearer_id, srsran::unique_byte_buffer_t pdu)
+  {
+    if (eutra_stack == nullptr) {
+      return;
+    }
+    eutra_stack->write_pdu(rnti, bearer_id, std::move(pdu));
+  }
+
 private:
   enb_stack_lte* eutra_stack = nullptr;
   gnb_stack_nr*  nr_stack    = nullptr;

srsenb/src/stack/enb_stack_lte.cc

@@ -281,4 +281,10 @@ void enb_stack_lte::run_thread()
   }
 }
 
+void enb_stack_lte::write_pdu(uint16_t rnti, uint32_t lcid, srsran::unique_byte_buffer_t pdu)
+{
+  // call GTPU adapter to map to EPS bearer
+  gtpu_adapter->write_pdu(rnti, lcid, std::move(pdu));
+}
+
 } // namespace srsenb

srsenb/src/stack/gnb_stack_nr.cc

@@ -80,7 +80,7 @@ int gnb_stack_nr::init(const srsenb::stack_args_t& args_,
   }
 
   rlc.init(&pdcp, &rrc, &mac, task_sched.get_timer_handler());
-  pdcp.init(&rlc, &rrc, nullptr);
+  pdcp.init(&rlc, &rrc, x2_);
 
   if (rrc.init(rrc_cfg_, phy, &mac, &rlc, &pdcp, nullptr, nullptr, x2_) != SRSRAN_SUCCESS) {
     stack_logger.error("Couldn't initialize RRC");