feat(smf): Added UL CL support in Downlink direction

Signed-off-by: Stefan Spettel <stefan.spettel@eurecom.fr>

src/smf_app/smf_pfcp_association.cpp

@@ -1097,6 +1097,31 @@ void upf_graph::dfs_next_upf(
             std::make_shared<smf_qos_flow>(qos_flow_asynch);
         edge_it.qos_flows.emplace_back(flow);
       }
+      // TODO thought for refactor: It would be much nicer if it would be the
+      // same edge object so we dont have to do that
+
+      // pointer is not null -> N9 interface
+      if (edge_it.association) {
+        // we add the TEID here for the edge in the other direction
+        // direct access is safe as we know the edge exists
+        auto edge_node = adjacency_list[edge_it.association];
+        for (auto edge_edge : edge_node) {
+          if (edge_edge.qos_flows.empty()) {
+            edge_edge.qos_flows.emplace_back(
+                std::make_shared<smf_qos_flow>(qos_flow_asynch));
+          }
+
+          if (edge_edge.association &&
+              edge_edge.association == node_it->first) {
+            if (edge_edge.type == iface_type::N9 && edge_edge.uplink) {
+              // downlink direction
+              edge_it.qos_flows[0]->dl_fteid = edge_edge.qos_flows[0]->dl_fteid;
+            } else if (edge_edge.type == iface_type::N9) {
+              edge_it.qos_flows[0]->ul_fteid = edge_edge.qos_flows[0]->ul_fteid;
+            }
+          }
+        }
+      }
 
       // set the correct edges to return
       if (edge_it.uplink) {

src/smf_app/smf_procedure.hpp

@@ -178,19 +178,19 @@ class session_create_sm_context_procedure : public smf_session_procedure {
       itti_n4_session_establishment_response& resp,
       std::shared_ptr<smf::smf_context> sc) override;
 
-  /**
-   * Sends a session establishment request, based on current UPF graph
-   * @return
-   */
-  smf_procedure_code send_n4_session_establishment_request();
-
   std::shared_ptr<itti_n4_session_establishment_request> n4_triggered;
 
   std::shared_ptr<itti_n11_create_sm_context_request> n11_trigger;
   std::shared_ptr<itti_n11_create_sm_context_response> n11_triggered_pending;
 
  private:
-  smf_qos_flow current_flow;
+  smf_qos_flow current_flow{};
+
+  /**
+   * Sends a session establishment request, based on current UPF graph
+   * @return
+   */
+  smf_procedure_code send_n4_session_establishment_request();
 };
 
 //------------------------------------------------------------------------------
@@ -231,6 +231,16 @@ class session_update_sm_context_procedure : public smf_session_procedure {
   std::shared_ptr<itti_n11_update_sm_context_request> n11_trigger;
   std::shared_ptr<itti_n11_update_sm_context_response> n11_triggered_pending;
   session_management_procedures_type_e session_procedure_type;
+
+ private:
+  // TODO currently support only one flow
+  smf_qos_flow current_flow{};
+  /**
+   * Sends a session modification request, based on the graph
+   * Does only consider normal DL procedures
+   * @return OK when successful, ERROR otherwise
+   */
+  smf_procedure_code send_n4_session_modification_request();
 };
 
 //------------------------------------------------------------------------------