NGAP Release Cplt: indicate release PDU sessions

We can optionally indicate the PDU session IDs. At least with OAI 5GC,
that should help it clean up.

openair2/COMMON/ngap_messages_types.h

@@ -583,6 +583,8 @@ typedef struct ngap_ue_ctxt_modification_resp_s {
 
 typedef struct ngap_ue_release_complete_s {
   uint32_t gNB_ue_ngap_id;
+  int num_pdu_sessions;
+  uint32_t pdu_session_id[256];
 } ngap_ue_release_complete_t;
 
 //-------------------------------------------------------------------------------------------//

openair2/RRC/NR/rrc_gNB.c

@@ -1810,7 +1810,10 @@ void rrc_remove_ue(gNB_RRC_INST *rrc, rrc_gNB_ue_context_t *ue_context_p)
    * are in E1, we also need to free the UE in the CU-CP, so call it twice to
    * cover all cases */
   nr_pdcp_remove_UE(UE->rrc_ue_id);
-  rrc_gNB_send_NGAP_UE_CONTEXT_RELEASE_COMPLETE(0, UE->rrc_ue_id);
+  uint32_t pdu_sessions[256];
+  for (int i = 0; i < UE->nb_of_pdusessions && i < 256; ++i)
+    pdu_sessions[i] = UE->pduSession[i].param.pdusession_id;
+  rrc_gNB_send_NGAP_UE_CONTEXT_RELEASE_COMPLETE(0, UE->rrc_ue_id, UE->nb_of_pdusessions, pdu_sessions);
   LOG_I(NR_RRC, "removed UE CU UE ID %u/RNTI %04x \n", UE->rrc_ue_id, UE->rnti);
   rrc_delete_ue_data(UE);
   rrc_gNB_remove_ue_context(rrc, ue_context_p);

openair2/RRC/NR/rrc_gNB_NGAP.c

@@ -1164,13 +1164,10 @@ int rrc_gNB_process_NGAP_UE_CONTEXT_RELEASE_COMMAND(MessageDef *msg_p, instance_
 
   if (ue_context_p == NULL) {
     /* Can not associate this message to an UE index */
-    MessageDef *msg_complete_p = NULL;
     LOG_W(NR_RRC, "[gNB %ld] In NGAP_UE_CONTEXT_RELEASE_COMMAND: unknown UE from gNB_ue_ngap_id (%u)\n",
           instance,
           gNB_ue_ngap_id);
-    msg_complete_p = itti_alloc_new_message(TASK_RRC_GNB, 0, NGAP_UE_CONTEXT_RELEASE_COMPLETE);
-    NGAP_UE_CONTEXT_RELEASE_COMPLETE(msg_complete_p).gNB_ue_ngap_id = gNB_ue_ngap_id;
-    itti_send_msg_to_task(TASK_NGAP, instance, msg_complete_p);
+    rrc_gNB_send_NGAP_UE_CONTEXT_RELEASE_COMPLETE(instance, gNB_ue_ngap_id, 0, NULL);
     return -1;
   }
 
@@ -1206,11 +1203,17 @@ int rrc_gNB_process_NGAP_UE_CONTEXT_RELEASE_COMMAND(MessageDef *msg_p, instance_
   return 0;
 }
 
-void rrc_gNB_send_NGAP_UE_CONTEXT_RELEASE_COMPLETE(
-  instance_t instance,
-  uint32_t   gNB_ue_ngap_id) {
+void rrc_gNB_send_NGAP_UE_CONTEXT_RELEASE_COMPLETE(instance_t instance,
+                                                   uint32_t gNB_ue_ngap_id,
+                                                   int num_pdu,
+                                                   uint32_t pdu_session_id[256])
+{
   MessageDef *msg = itti_alloc_new_message(TASK_RRC_GNB, 0, NGAP_UE_CONTEXT_RELEASE_COMPLETE);
   NGAP_UE_CONTEXT_RELEASE_COMPLETE(msg).gNB_ue_ngap_id = gNB_ue_ngap_id;
+  NGAP_UE_CONTEXT_RELEASE_COMPLETE(msg).num_pdu_sessions = num_pdu;
+  for (int i = 0; i < num_pdu; ++i)
+    NGAP_UE_CONTEXT_RELEASE_COMPLETE(msg).pdu_session_id[i] = pdu_session_id[i];
+  LOG_W(RRC, "trigger release with %d pdu\n", num_pdu);
   itti_send_msg_to_task(TASK_NGAP, instance, msg);
 }
 

openair2/RRC/NR/rrc_gNB_NGAP.h

@@ -94,7 +94,10 @@ int rrc_gNB_process_NGAP_UE_CONTEXT_RELEASE_REQ(MessageDef *msg_p, instance_t in
 
 int rrc_gNB_process_NGAP_UE_CONTEXT_RELEASE_COMMAND(MessageDef *msg_p, instance_t instance);
 
-void rrc_gNB_send_NGAP_UE_CONTEXT_RELEASE_COMPLETE(instance_t instance, uint32_t gNB_ue_ngap_id);
+void rrc_gNB_send_NGAP_UE_CONTEXT_RELEASE_COMPLETE(instance_t instance,
+                                                   uint32_t gNB_ue_ngap_id,
+                                                   int num_pdu,
+                                                   uint32_t pdu_session_id[256]);
 
 void rrc_gNB_send_NGAP_UE_CAPABILITIES_IND(const protocol_ctxt_t *const ctxt_pP,
                                            rrc_gNB_ue_context_t *const ue_context_pP,

openair3/NGAP/ngap_gNB_context_management_procedures.c

@@ -50,7 +50,7 @@
 #include "ngap_gNB_management_procedures.h"
 #include "ngap_gNB_context_management_procedures.h"
 #include "NGAP_PDUSessionResourceItemCxtRelReq.h"
-
+#include "NGAP_PDUSessionResourceItemCxtRelCpl.h"
 
 int ngap_ue_context_release_complete(instance_t instance,
                                      ngap_ue_release_complete_t *ue_release_complete_p)
@@ -100,6 +100,20 @@ int ngap_ue_context_release_complete(instance_t instance,
     ie->value.choice.RAN_UE_NGAP_ID = ue_release_complete_p->gNB_ue_ngap_id;
   }
 
+  /* number of PDU sessions */
+  if (ue_release_complete_p->num_pdu_sessions > 0) {
+    asn1cSequenceAdd(out->protocolIEs.list, NGAP_UEContextReleaseComplete_IEs_t, ie);
+    ie->id = NGAP_ProtocolIE_ID_id_PDUSessionResourceListCxtRelCpl;
+    ie->criticality = NGAP_Criticality_reject;
+    ie->value.present = NGAP_UEContextReleaseComplete_IEs__value_PR_PDUSessionResourceListCxtRelCpl;
+    NGAP_PDUSessionResourceListCxtRelCpl_t *l = &ie->value.choice.PDUSessionResourceListCxtRelCpl;
+    DevAssert(ue_release_complete_p->num_pdu_sessions <= 256);
+    for (int i = 0; i < ue_release_complete_p->num_pdu_sessions; ++i) {
+      asn1cSequenceAdd(l->list, NGAP_PDUSessionResourceItemCxtRelCpl_t, pdu);
+      pdu->pDUSessionID = ue_release_complete_p->pdu_session_id[i];
+    }
+  }
+
   if (ngap_gNB_encode_pdu(&pdu, &buffer, &length) < 0) {
     /* Encode procedure has failed... */
     NGAP_ERROR("Failed to encode UE context release complete\n");