Handle DRB release at MAC

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c

@@ -2750,6 +2750,14 @@ static void nr_mac_apply_cellgroup(gNB_MAC_INST *mac, NR_UE_info_t *UE, frame_t
 
     if (LOG_DEBUGFLAG(DEBUG_ASN1))
       xer_fprint(stdout, &asn_DEF_NR_CellGroupConfig, (const void *)UE->CellGroup);
+
+    /* remove the rlc_BearerToReleaseList, we don't need it anymore */
+    if (UE->CellGroup->rlc_BearerToReleaseList != NULL) {
+      struct NR_CellGroupConfig__rlc_BearerToReleaseList *l = UE->CellGroup->rlc_BearerToReleaseList;
+      asn_sequence_del(&l->list, l->list.count, /* free */1);
+      free(UE->CellGroup->rlc_BearerToReleaseList);
+      UE->CellGroup->rlc_BearerToReleaseList = NULL;
+    }
   }
 
   NR_ServingCellConfigCommon_t *scc = mac->common_channels[0].ServingCellConfigCommon;

openair2/LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c

@@ -138,6 +138,42 @@ static int handle_ue_context_drbs_setup(int rnti,
   return drbs_len;
 }
 
+static int handle_ue_context_drbs_release(int rnti,
+                                          int drbs_len,
+                                          const f1ap_drb_to_be_released_t *req_drbs,
+                                          NR_CellGroupConfig_t *cellGroupConfig)
+{
+  DevAssert(req_drbs != NULL && cellGroupConfig != NULL);
+
+  cellGroupConfig->rlc_BearerToReleaseList = calloc(1, sizeof(*cellGroupConfig->rlc_BearerToReleaseList));
+  AssertFatal(cellGroupConfig->rlc_BearerToReleaseList != NULL, "out of memory\n");
+
+  /* Note: the actual GTP tunnels are already removed in the F1AP message
+   * decoding */
+  for (int i = 0; i < drbs_len; i++) {
+    const f1ap_drb_to_be_released_t *drb = &req_drbs[i];
+
+    long lcid = drb->rb_id + 3; /* LCID is DRB + 3 */
+    int idx = 0;
+    while (idx < cellGroupConfig->rlc_BearerToAddModList->list.count) {
+      const NR_RLC_BearerConfig_t *bc = cellGroupConfig->rlc_BearerToAddModList->list.array[idx];
+      if (bc->logicalChannelIdentity == lcid)
+        break;
+      ++idx;
+    }
+    if (idx < cellGroupConfig->rlc_BearerToAddModList->list.count) {
+      nr_rlc_release_entity(rnti, lcid);
+      asn_sequence_del(&cellGroupConfig->rlc_BearerToAddModList->list, idx, 1);
+      long *plcid = malloc(sizeof(*plcid));
+      AssertFatal(plcid != NULL, "out of memory\n");
+      *plcid = lcid;
+      int ret = ASN_SEQUENCE_ADD(&cellGroupConfig->rlc_BearerToReleaseList->list, plcid);
+      DevAssert(ret == 0);
+    }
+  }
+  return drbs_len;
+}
+
 static NR_UE_NR_Capability_t *get_ue_nr_cap(int rnti, uint8_t *buf, uint32_t len)
 {
   if (buf == NULL || len == 0)
@@ -311,6 +347,11 @@ void ue_context_modification_request(const f1ap_ue_context_modif_req_t *req)
                                                                 new_CellGroup);
   }
 
+  if (req->drbs_to_be_released_length > 0) {
+    resp.drbs_to_be_released_length =
+        handle_ue_context_drbs_release(req->gNB_DU_ue_id, req->drbs_to_be_released_length, req->drbs_to_be_released, new_CellGroup);
+  }
+
   if (req->rrc_container != NULL)
     nr_rlc_srb_recv_sdu(req->gNB_DU_ue_id, DCCH, req->rrc_container, req->rrc_container_length);
 
@@ -328,7 +369,7 @@ void ue_context_modification_request(const f1ap_ue_context_modif_req_t *req)
     update_cellGroupConfig(new_CellGroup, UE->uid, UE->capability, &mac->radio_config, scc);
   }
 
-  if (req->srbs_to_be_setup_length > 0 || req->drbs_to_be_setup_length > 0 || ue_cap != NULL) {
+  if (req->srbs_to_be_setup_length > 0 || req->drbs_to_be_setup_length > 0 || req->drbs_to_be_released_length > 0) {
     resp.du_to_cu_rrc_information = calloc(1, sizeof(du_to_cu_rrc_information_t));
     AssertFatal(resp.du_to_cu_rrc_information != NULL, "out of memory\n");
     resp.du_to_cu_rrc_information->cellGroupConfig = calloc(1, 1024);