From 2e252dd377acafe1eac50a1ef51414465dc2c21c Mon Sep 17 00:00:00 2001
From: Robert Schmidt <robert.schmidt@openairinterface.org>
Date: Sun, 8 Oct 2023 16:26:54 +0200
Subject: [PATCH] Implement E1 bearer release

---
 openair1/SIMULATION/NR_PHY/dlsim.c          |  1 +
 openair1/SIMULATION/NR_PHY/ulsim.c          |  1 +
 openair2/COMMON/e1ap_messages_def.h         |  3 ++
 openair2/COMMON/e1ap_messages_types.h       |  7 ++++
 openair2/E1AP/CMakeLists.txt                |  2 +-
 openair2/E1AP/e1ap.c                        | 32 ++++++++++-----
 openair2/E1AP/e1ap.h                        |  2 +-
 openair2/E1AP/e1ap_api.c                    | 44 ---------------------
 openair2/E1AP/e1ap_api.h                    |  4 +-
 openair2/E1AP/e1ap_common.c                 |  6 +++
 openair2/LAYER2/nr_pdcp/cucp_cuup_handler.c | 21 ++++++++++
 openair2/LAYER2/nr_pdcp/cucp_cuup_handler.h |  2 +
 openair2/LAYER2/nr_pdcp/cuup_cucp_direct.c  |  9 +++++
 openair2/LAYER2/nr_pdcp/cuup_cucp_e1ap.c    |  9 +++++
 openair2/LAYER2/nr_pdcp/cuup_cucp_if.h      |  3 ++
 openair2/RRC/NR/cucp_cuup_direct.c          |  7 ++++
 openair2/RRC/NR/cucp_cuup_e1ap.c            | 11 ++++++
 openair2/RRC/NR/cucp_cuup_if.h              |  2 +
 openair2/RRC/NR/nr_rrc_defs.h               |  1 +
 openair2/RRC/NR/rrc_gNB.c                   | 22 ++++++++++-
 20 files changed, 129 insertions(+), 60 deletions(-)
 delete mode 100644 openair2/E1AP/e1ap_api.c

diff --git a/openair1/SIMULATION/NR_PHY/dlsim.c b/openair1/SIMULATION/NR_PHY/dlsim.c
index 163107bf84..21a237785d 100644
--- a/openair1/SIMULATION/NR_PHY/dlsim.c
+++ b/openair1/SIMULATION/NR_PHY/dlsim.c
@@ -110,6 +110,7 @@ void nr_rrc_ue_generate_RRCSetupRequest(module_id_t module_id, const uint8_t gNB
 
 void e1_bearer_context_setup(const e1ap_bearer_setup_req_t *req) { abort(); }
 void e1_bearer_context_modif(const e1ap_bearer_setup_req_t *req) { abort(); }
+void e1_bearer_release_cmd(const e1ap_bearer_release_cmd_t *cmd) { abort(); }
 
 int8_t nr_rrc_RA_succeeded(const module_id_t mod_id, const uint8_t gNB_index) {
   return 0;
diff --git a/openair1/SIMULATION/NR_PHY/ulsim.c b/openair1/SIMULATION/NR_PHY/ulsim.c
index 7a7058f2f1..668c1cb633 100644
--- a/openair1/SIMULATION/NR_PHY/ulsim.c
+++ b/openair1/SIMULATION/NR_PHY/ulsim.c
@@ -106,6 +106,7 @@ void nr_rrc_ue_generate_RRCSetupRequest(module_id_t module_id, const uint8_t gNB
 
 void e1_bearer_context_setup(const e1ap_bearer_setup_req_t *req) { abort(); }
 void e1_bearer_context_modif(const e1ap_bearer_setup_req_t *req) { abort(); }
+void e1_bearer_release_cmd(const e1ap_bearer_release_cmd_t *cmd) { abort(); }
 
 int8_t nr_rrc_RA_succeeded(const module_id_t mod_id, const uint8_t gNB_index) {
   return 0;
diff --git a/openair2/COMMON/e1ap_messages_def.h b/openair2/COMMON/e1ap_messages_def.h
index 2759c655ef..ea24ac9e18 100644
--- a/openair2/COMMON/e1ap_messages_def.h
+++ b/openair2/COMMON/e1ap_messages_def.h
@@ -34,3 +34,6 @@ MESSAGE_DEF(E1AP_BEARER_CONTEXT_SETUP_RESP , MESSAGE_PRIORITY_MED , e1ap_bearer_
 
 MESSAGE_DEF(E1AP_BEARER_CONTEXT_MODIFICATION_REQ , MESSAGE_PRIORITY_MED , e1ap_bearer_setup_req_t , e1ap_bearer_mod_req)
 MESSAGE_DEF(E1AP_BEARER_CONTEXT_MODIFICATION_RESP, MESSAGE_PRIORITY_MED, e1ap_bearer_modif_resp_t, e1ap_bearer_modif_resp)
+
+MESSAGE_DEF(E1AP_BEARER_CONTEXT_RELEASE_CMD, MESSAGE_PRIORITY_MED, e1ap_bearer_release_cmd_t, e1ap_bearer_release_cmd)
+MESSAGE_DEF(E1AP_BEARER_CONTEXT_RELEASE_CPLT, MESSAGE_PRIORITY_MED, e1ap_bearer_release_cplt_t, e1ap_bearer_release_cplt)
diff --git a/openair2/COMMON/e1ap_messages_types.h b/openair2/COMMON/e1ap_messages_types.h
index 124a174dab..f98058b85c 100644
--- a/openair2/COMMON/e1ap_messages_types.h
+++ b/openair2/COMMON/e1ap_messages_types.h
@@ -48,6 +48,8 @@
 #define E1AP_BEARER_CONTEXT_SETUP_RESP(mSGpTR)            (mSGpTR)->ittiMsg.e1ap_bearer_setup_resp
 #define E1AP_BEARER_CONTEXT_MODIFICATION_REQ(mSGpTR)      (mSGpTR)->ittiMsg.e1ap_bearer_setup_req
 #define E1AP_BEARER_CONTEXT_MODIFICATION_RESP(mSGpTR)     (mSGpTR)->ittiMsg.e1ap_bearer_modif_resp
+#define E1AP_BEARER_CONTEXT_RELEASE_CMD(mSGpTR)           (mSGpTR)->ittiMsg.e1ap_bearer_release_cmd
+#define E1AP_BEARER_CONTEXT_RELEASE_CPLT(mSGpTR)          (mSGpTR)->ittiMsg.e1ap_bearer_release_cplt
 
 typedef f1ap_net_ip_address_t e1ap_net_ip_address_t;
 
@@ -193,6 +195,11 @@ typedef struct e1ap_bearer_release_cmd_s {
   long cause;
 } e1ap_bearer_release_cmd_t;
 
+typedef struct e1ap_bearer_release_cplt_s {
+  uint32_t gNB_cu_cp_ue_id;
+  uint32_t gNB_cu_up_ue_id;
+} e1ap_bearer_release_cplt_t;
+
 typedef struct qos_flow_setup_s {
   long id;
 } qos_flow_setup_t;
diff --git a/openair2/E1AP/CMakeLists.txt b/openair2/E1AP/CMakeLists.txt
index 0384c2860b..c7657eed5a 100644
--- a/openair2/E1AP/CMakeLists.txt
+++ b/openair2/E1AP/CMakeLists.txt
@@ -1,6 +1,6 @@
 add_subdirectory(MESSAGES)
 
-add_library(e1ap e1ap.c e1ap_common.c e1ap_api.c)
+add_library(e1ap e1ap.c e1ap_common.c)
 target_link_libraries(e1ap
                       PUBLIC asn1_e1ap f1ap
                       PRIVATE asn1_nr_rrc_hdrs asn1_lte_rrc_hdrs asn1_f1ap UTIL e1_if)
diff --git a/openair2/E1AP/e1ap.c b/openair2/E1AP/e1ap.c
index a6e6886284..d6116309db 100644
--- a/openair2/E1AP/e1ap.c
+++ b/openair2/E1AP/e1ap.c
@@ -1505,7 +1505,7 @@ int e1apCUCP_send_BEARER_CONTEXT_RELEASE_COMMAND(sctp_assoc_t assoc_id, e1ap_bea
   return e1ap_encode_send(CPtype, assoc_id, &pdu, 0, __func__);
 }
 
-static int fill_BEARER_CONTEXT_RELEASE_COMPLETE(e1ap_bearer_release_cmd_t *const cmd, E1AP_E1AP_PDU_t *pdu)
+static int fill_BEARER_CONTEXT_RELEASE_COMPLETE(const e1ap_bearer_release_cplt_t *cplt, E1AP_E1AP_PDU_t *pdu)
 {
   pdu->present = E1AP_E1AP_PDU_PR_successfulOutcome;
   asn1cCalloc(pdu->choice.successfulOutcome, msg);
@@ -1519,22 +1519,22 @@ static int fill_BEARER_CONTEXT_RELEASE_COMPLETE(e1ap_bearer_release_cmd_t *const
   ieC1->id                         = E1AP_ProtocolIE_ID_id_gNB_CU_CP_UE_E1AP_ID;
   ieC1->criticality                = E1AP_Criticality_reject;
   ieC1->value.present              = E1AP_BearerContextReleaseCompleteIEs__value_PR_GNB_CU_CP_UE_E1AP_ID;
-  ieC1->value.choice.GNB_CU_CP_UE_E1AP_ID = cmd->gNB_cu_cp_ue_id;
+  ieC1->value.choice.GNB_CU_CP_UE_E1AP_ID = cplt->gNB_cu_cp_ue_id;
   /* mandatory */
   /* c2. gNB-CU-UP UE E1AP ID */
   asn1cSequenceAdd(out->protocolIEs.list, E1AP_BearerContextReleaseCompleteIEs_t, ieC2);
   ieC2->id                         = E1AP_ProtocolIE_ID_id_gNB_CU_UP_UE_E1AP_ID;
   ieC2->criticality                = E1AP_Criticality_reject;
   ieC2->value.present              = E1AP_BearerContextReleaseCompleteIEs__value_PR_GNB_CU_UP_UE_E1AP_ID;
-  ieC2->value.choice.GNB_CU_UP_UE_E1AP_ID = cmd->gNB_cu_cp_ue_id;
+  ieC2->value.choice.GNB_CU_UP_UE_E1AP_ID = cplt->gNB_cu_cp_ue_id;
 
   return 0;
 }
 
-int e1apCUUP_send_BEARER_CONTEXT_RELEASE_COMPLETE(sctp_assoc_t assoc_id, e1ap_bearer_release_cmd_t *const cmd)
+int e1apCUUP_send_BEARER_CONTEXT_RELEASE_COMPLETE(sctp_assoc_t assoc_id, const e1ap_bearer_release_cplt_t *cplt)
 {
   E1AP_E1AP_PDU_t pdu = {0};
-  fill_BEARER_CONTEXT_RELEASE_COMPLETE(cmd, &pdu);
+  fill_BEARER_CONTEXT_RELEASE_COMPLETE(cplt, &pdu);
   return e1ap_encode_send(CPtype, assoc_id, &pdu, 0, __func__);
 }
 
@@ -1592,12 +1592,12 @@ int e1apCUUP_handle_BEARER_CONTEXT_RELEASE_COMMAND(sctp_assoc_t assoc_id, e1ap_u
 
   e1ap_bearer_release_cmd_t bearerCxt = {0};
   extract_BEARER_CONTEXT_RELEASE_COMMAND(pdu, &bearerCxt);
-  CUUP_process_bearer_release_command(e1_inst->instance, &bearerCxt);
+  e1_bearer_release_cmd(&bearerCxt);
   return 0;
 }
 
 void extract_BEARER_CONTEXT_RELEASE_COMPLETE(const E1AP_E1AP_PDU_t *pdu,
-                                             e1ap_bearer_release_cmd_t *bearerCxt) {
+                                             e1ap_bearer_release_cplt_t *bearerCxt) {
   const E1AP_BearerContextReleaseComplete_t *in = &pdu->choice.successfulOutcome->value.choice.BearerContextReleaseComplete;
   E1AP_BearerContextReleaseCompleteIEs_t *ie;
 
@@ -1634,9 +1634,12 @@ int e1apCUCP_handle_BEARER_CONTEXT_RELEASE_COMPLETE(sctp_assoc_t assoc_id, e1ap_
   DevAssert(pdu->choice.successfulOutcome->criticality == E1AP_Criticality_reject);
   DevAssert(pdu->choice.successfulOutcome->value.present == E1AP_SuccessfulOutcome__value_PR_BearerContextReleaseComplete);
 
-  e1ap_bearer_release_cmd_t bearerCxt = {0};
+  e1ap_bearer_release_cplt_t bearerCxt = {0};
   extract_BEARER_CONTEXT_RELEASE_COMPLETE(pdu, &bearerCxt);
-  //TODO: CUCP_process_bearer_release_complete(&beareCxt, instance);
+  MessageDef *msg = itti_alloc_new_message(TASK_CUUP_E1, 0, E1AP_BEARER_CONTEXT_RELEASE_CPLT);
+  e1ap_bearer_release_cplt_t *cplt = &E1AP_BEARER_CONTEXT_RELEASE_CPLT(msg);
+  *cplt = bearerCxt;
+  itti_send_msg_to_task(TASK_RRC_GNB, 0, msg);
   return 0;
 }
 
@@ -1864,6 +1867,10 @@ void *E1AP_CUCP_task(void *arg) {
         e1apCUCP_send_BEARER_CONTEXT_MODIFICATION_REQUEST(assoc_id, &E1AP_BEARER_CONTEXT_SETUP_REQ(msg));
         break;
 
+      case E1AP_BEARER_CONTEXT_RELEASE_CMD:
+        e1apCUCP_send_BEARER_CONTEXT_RELEASE_COMMAND(assoc_id, &E1AP_BEARER_CONTEXT_RELEASE_CMD(msg));
+        break;
+
       default:
         LOG_E(E1AP, "Unknown message received in TASK_CUCP_E1\n");
         break;
@@ -1921,6 +1928,13 @@ void *E1AP_CUUP_task(void *arg) {
         e1apCUUP_send_BEARER_CONTEXT_MODIFICATION_RESPONSE(inst->cuup.assoc_id, resp);
         } break;
 
+      case E1AP_BEARER_CONTEXT_RELEASE_CPLT: {
+        const e1ap_bearer_release_cplt_t *cplt = &E1AP_BEARER_CONTEXT_RELEASE_CPLT(msg);
+        const e1ap_upcp_inst_t *inst = getCxtE1(myInstance);
+        AssertFatal(inst != NULL, "no E1 instance found for instance %ld\n", myInstance);
+        e1apCUUP_send_BEARER_CONTEXT_RELEASE_COMPLETE(inst->cuup.assoc_id, cplt);
+        } break;
+
       default:
         LOG_E(E1AP, "Unknown message received in TASK_CUUP_E1\n");
         break;
diff --git a/openair2/E1AP/e1ap.h b/openair2/E1AP/e1ap.h
index fd82ffd147..b41559de09 100644
--- a/openair2/E1AP/e1ap.h
+++ b/openair2/E1AP/e1ap.h
@@ -50,7 +50,7 @@ int e1apCUUP_handle_BEARER_CONTEXT_RELEASE_COMMAND(sctp_assoc_t assoc_id, e1ap_u
 
 int e1apCUCP_handle_BEARER_CONTEXT_RELEASE_COMPLETE(sctp_assoc_t assoc_id, e1ap_upcp_inst_t *inst, const E1AP_E1AP_PDU_t *pdu);
 
-int e1apCUUP_send_BEARER_CONTEXT_RELEASE_COMPLETE(sctp_assoc_t assoc_id, e1ap_bearer_release_cmd_t *const cmd);
+int e1apCUUP_send_BEARER_CONTEXT_RELEASE_COMPLETE(sctp_assoc_t assoc_id, const e1ap_bearer_release_cplt_t *cplt);
 
 void *E1AP_CUUP_task(void *arg);
 
diff --git a/openair2/E1AP/e1ap_api.c b/openair2/E1AP/e1ap_api.c
deleted file mode 100644
index dfb6747600..0000000000
--- a/openair2/E1AP/e1ap_api.c
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The OpenAirInterface Software Alliance licenses this file to You under
- * the OAI Public License, Version 1.1  (the "License"); you may not use this file
- * except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.openairinterface.org/?page_id=698
- *
- * Author and copyright: Laurent Thomas, open-cells.com
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *-------------------------------------------------------------------------------
- * For more information about the OpenAirInterface (OAI) Software Alliance:
- *      contact@openairinterface.org
- */
-
-#include <arpa/inet.h>
-#include "e1ap_api.h"
-
-#include "nr_pdcp/nr_pdcp_entity.h"
-#include "openair2/RRC/NR/cucp_cuup_if.h"
-#include "openair2/RRC/LTE/MESSAGES/asn1_msg.h"
-#include "openair3/SECU/key_nas_deriver.h"
-#include "openair3/ocp-gtpu/gtp_itf.h"
-#include "openair2/F1AP/f1ap_ids.h"
-#include "e1ap_asnc.h"
-#include "e1ap_common.h"
-#include "e1ap.h"
-
-void CUUP_process_bearer_release_command(instance_t instance, e1ap_bearer_release_cmd_t *const cmd)
-{
-  e1ap_upcp_inst_t *inst = getCxtE1(instance);
-  AssertFatal(inst, "");
-  newGtpuDeleteAllTunnels(inst->gtpInstN3, cmd->gNB_cu_up_ue_id);
-  newGtpuDeleteAllTunnels(inst->gtpInstF1U, cmd->gNB_cu_up_ue_id);
-  e1apCUUP_send_BEARER_CONTEXT_RELEASE_COMPLETE(inst->cuup.assoc_id, cmd);
-}
diff --git a/openair2/E1AP/e1ap_api.h b/openair2/E1AP/e1ap_api.h
index e2d0c892d1..a3759399c7 100644
--- a/openair2/E1AP/e1ap_api.h
+++ b/openair2/E1AP/e1ap_api.h
@@ -25,9 +25,7 @@
 #define E1AP_API_H
 
 #include "platform_types.h"
-#include "openair2/COMMON/e1ap_messages_types.h"
-#include "openair2/E1AP/e1ap_common.h"
+
 void cuup_init_n3(instance_t instance);
 
-void CUUP_process_bearer_release_command(instance_t, e1ap_bearer_release_cmd_t *const cmd);
 #endif
diff --git a/openair2/E1AP/e1ap_common.c b/openair2/E1AP/e1ap_common.c
index 0547680eea..cf8982339d 100644
--- a/openair2/E1AP/e1ap_common.c
+++ b/openair2/E1AP/e1ap_common.c
@@ -117,6 +117,9 @@ int e1ap_decode_initiating_message(E1AP_E1AP_PDU_t *pdu) {
     case E1AP_ProcedureCode_id_bearerContextModification:
       break;
 
+    case E1AP_ProcedureCode_id_bearerContextRelease:
+      break;
+
     default:
       LOG_E(E1AP, "Unsupported procedure code (%d) for initiating message\n",
             (int)pdu->choice.initiatingMessage->procedureCode);
@@ -137,6 +140,9 @@ int e1ap_decode_successful_outcome(E1AP_E1AP_PDU_t *pdu) {
     case E1AP_ProcedureCode_id_bearerContextModification:
       break;
 
+    case E1AP_ProcedureCode_id_bearerContextRelease:
+      break;
+
     default:
       LOG_E(E1AP, "Unsupported procedure code (%d) for successful message\n",
             (int)pdu->choice.successfulOutcome->procedureCode);
diff --git a/openair2/LAYER2/nr_pdcp/cucp_cuup_handler.c b/openair2/LAYER2/nr_pdcp/cucp_cuup_handler.c
index aaf5323b03..d661f9c6f4 100644
--- a/openair2/LAYER2/nr_pdcp/cucp_cuup_handler.c
+++ b/openair2/LAYER2/nr_pdcp/cucp_cuup_handler.c
@@ -257,3 +257,24 @@ void e1_bearer_context_modif(const e1ap_bearer_setup_req_t *req)
 
   get_e1_if()->bearer_modif_response(&modif);
 }
+
+void e1_bearer_release_cmd(const e1ap_bearer_release_cmd_t *cmd)
+{
+  instance_t n3inst = get_n3_gtp_instance();
+  instance_t f1inst = get_f1_gtp_instance();
+
+  LOG_I(E1AP, "releasing UE %d\n", cmd->gNB_cu_up_ue_id);
+
+  newGtpuDeleteAllTunnels(n3inst, cmd->gNB_cu_up_ue_id);
+  if (f1inst >= 0)  // is there F1-U?
+    newGtpuDeleteAllTunnels(f1inst, cmd->gNB_cu_up_ue_id);
+  nr_pdcp_remove_UE(cmd->gNB_cu_up_ue_id);
+  cu_remove_f1_ue_data(cmd->gNB_cu_up_ue_id);
+
+  e1ap_bearer_release_cplt_t cplt = {
+    .gNB_cu_cp_ue_id = cmd->gNB_cu_cp_ue_id,
+    .gNB_cu_up_ue_id = cmd->gNB_cu_up_ue_id,
+  };
+
+  get_e1_if()->bearer_release_complete(&cplt);
+}
diff --git a/openair2/LAYER2/nr_pdcp/cucp_cuup_handler.h b/openair2/LAYER2/nr_pdcp/cucp_cuup_handler.h
index 7c9c6244f3..7290043371 100644
--- a/openair2/LAYER2/nr_pdcp/cucp_cuup_handler.h
+++ b/openair2/LAYER2/nr_pdcp/cucp_cuup_handler.h
@@ -27,7 +27,9 @@
 void nr_pdcp_e1_if_init(bool uses_e1);
 
 struct e1ap_bearer_setup_req_s;
+struct e1ap_bearer_release_cmd_s;
 void e1_bearer_context_setup(const struct e1ap_bearer_setup_req_s *req);
 void e1_bearer_context_modif(const struct e1ap_bearer_setup_req_s *req);
+void e1_bearer_release_cmd(const struct e1ap_bearer_release_cmd_s *cmd);
 
 #endif /* CUCP_CUUP_HANDLER_H */
diff --git a/openair2/LAYER2/nr_pdcp/cuup_cucp_direct.c b/openair2/LAYER2/nr_pdcp/cuup_cucp_direct.c
index 52918b4d64..b6ad66e18c 100644
--- a/openair2/LAYER2/nr_pdcp/cuup_cucp_direct.c
+++ b/openair2/LAYER2/nr_pdcp/cuup_cucp_direct.c
@@ -39,8 +39,17 @@ static void bearer_modif_response_direct(const e1ap_bearer_modif_resp_t *resp)
   itti_send_msg_to_task(TASK_RRC_GNB, 0, msg);
 }
 
+static void bearer_release_complete_direct(const e1ap_bearer_release_cplt_t *cplt)
+{
+  MessageDef *msg = itti_alloc_new_message(TASK_MAC_GNB, 0, E1AP_BEARER_CONTEXT_RELEASE_CPLT);
+  e1ap_bearer_release_cplt_t *msg_cplt = &E1AP_BEARER_CONTEXT_RELEASE_CPLT(msg);
+  *msg_cplt = *cplt;
+  itti_send_msg_to_task(TASK_RRC_GNB, 0, msg);
+}
+
 void cuup_cucp_init_direct(e1_if_t *iface)
 {
   iface->bearer_setup_response = bearer_setup_response_direct;
   iface->bearer_modif_response = bearer_modif_response_direct;
+  iface->bearer_release_complete = bearer_release_complete_direct;
 }
diff --git a/openair2/LAYER2/nr_pdcp/cuup_cucp_e1ap.c b/openair2/LAYER2/nr_pdcp/cuup_cucp_e1ap.c
index 91ed1b1ec8..8454d5a7d8 100644
--- a/openair2/LAYER2/nr_pdcp/cuup_cucp_e1ap.c
+++ b/openair2/LAYER2/nr_pdcp/cuup_cucp_e1ap.c
@@ -39,8 +39,17 @@ static void bearer_modif_response_e1ap(const e1ap_bearer_modif_resp_t *resp)
   itti_send_msg_to_task (TASK_CUUP_E1, 0, msg_p);
 }
 
+static void bearer_release_complete_e1ap(const e1ap_bearer_release_cplt_t *cplt)
+{
+  MessageDef *msg_p = itti_alloc_new_message(TASK_CUUP_E1, 0, E1AP_BEARER_CONTEXT_RELEASE_CPLT);
+  e1ap_bearer_release_cplt_t *msg_cplt = &E1AP_BEARER_CONTEXT_RELEASE_CPLT(msg_p);
+  *msg_cplt = *cplt;
+  itti_send_msg_to_task (TASK_CUUP_E1, 0, msg_p);
+}
+
 void cuup_cucp_init_e1ap(e1_if_t *iface)
 {
   iface->bearer_setup_response = bearer_setup_response_e1ap;
   iface->bearer_modif_response = bearer_modif_response_e1ap;
+  iface->bearer_release_complete = bearer_release_complete_e1ap;
 }
diff --git a/openair2/LAYER2/nr_pdcp/cuup_cucp_if.h b/openair2/LAYER2/nr_pdcp/cuup_cucp_if.h
index 3a576b7f7f..c33694dac3 100644
--- a/openair2/LAYER2/nr_pdcp/cuup_cucp_if.h
+++ b/openair2/LAYER2/nr_pdcp/cuup_cucp_if.h
@@ -26,12 +26,15 @@
 
 struct e1ap_bearer_setup_resp_s;
 struct e1ap_bearer_modif_resp_s;
+struct e1ap_bearer_release_cplt_s;
 typedef void (*e1_bearer_setup_response_func_t)(const struct e1ap_bearer_setup_resp_s *resp);
 typedef void (*e1_bearer_modif_response_func_t)(const struct e1ap_bearer_modif_resp_s *resp);
+typedef void (*e1_bearer_release_complete_func_t)(const struct e1ap_bearer_release_cplt_s *cplt);
 
 typedef struct e1_if_t {
   e1_bearer_setup_response_func_t bearer_setup_response;
   e1_bearer_modif_response_func_t bearer_modif_response;
+  e1_bearer_release_complete_func_t bearer_release_complete;
 } e1_if_t;
 
 e1_if_t *get_e1_if(void);
diff --git a/openair2/RRC/NR/cucp_cuup_direct.c b/openair2/RRC/NR/cucp_cuup_direct.c
index 3c45598f15..ee3555a14b 100644
--- a/openair2/RRC/NR/cucp_cuup_direct.c
+++ b/openair2/RRC/NR/cucp_cuup_direct.c
@@ -37,7 +37,14 @@ static void cucp_cuup_bearer_context_modif_direct(sctp_assoc_t assoc_id, const e
   e1_bearer_context_modif(req);
 }
 
+static void cucp_cuup_bearer_context_release_cmd_direct(sctp_assoc_t assoc_id, const e1ap_bearer_release_cmd_t *cmd)
+{
+  AssertFatal(assoc_id == -1, "illegal assoc_id %d, impossible for integrated CU\n", assoc_id);
+  e1_bearer_release_cmd(cmd);
+}
+
 void cucp_cuup_message_transfer_direct_init(gNB_RRC_INST *rrc) {
   rrc->cucp_cuup.bearer_context_setup = cucp_cuup_bearer_context_setup_direct;
   rrc->cucp_cuup.bearer_context_mod = cucp_cuup_bearer_context_modif_direct;
+  rrc->cucp_cuup.bearer_context_release = cucp_cuup_bearer_context_release_cmd_direct;
 }
diff --git a/openair2/RRC/NR/cucp_cuup_e1ap.c b/openair2/RRC/NR/cucp_cuup_e1ap.c
index 1678dd8313..fb099178d4 100644
--- a/openair2/RRC/NR/cucp_cuup_e1ap.c
+++ b/openair2/RRC/NR/cucp_cuup_e1ap.c
@@ -47,7 +47,18 @@ static void cucp_cuup_bearer_context_mod_e1ap(sctp_assoc_t assoc_id, const e1ap_
   itti_send_msg_to_task(TASK_CUCP_E1, 0, msg);
 }
 
+static void cucp_cuup_bearer_context_release_cmd_e1ap(sctp_assoc_t assoc_id, const e1ap_bearer_release_cmd_t *cmd)
+{
+  AssertFatal(assoc_id > 0, "illegal assoc_id %d\n", assoc_id);
+  MessageDef *msg = itti_alloc_new_message(TASK_CUCP_E1, 0, E1AP_BEARER_CONTEXT_RELEASE_CMD);
+  msg->ittiMsgHeader.originInstance = assoc_id;
+  e1ap_bearer_release_cmd_t *cmd_msg = &E1AP_BEARER_CONTEXT_RELEASE_CMD(msg);
+  memcpy(cmd_msg, cmd, sizeof(*cmd));
+  itti_send_msg_to_task(TASK_CUCP_E1, 0, msg);
+}
+
 void cucp_cuup_message_transfer_e1ap_init(gNB_RRC_INST *rrc) {
   rrc->cucp_cuup.bearer_context_setup = cucp_cuup_bearer_context_setup_e1ap;
   rrc->cucp_cuup.bearer_context_mod = cucp_cuup_bearer_context_mod_e1ap;
+  rrc->cucp_cuup.bearer_context_release = cucp_cuup_bearer_context_release_cmd_e1ap;
 }
diff --git a/openair2/RRC/NR/cucp_cuup_if.h b/openair2/RRC/NR/cucp_cuup_if.h
index 125ae93522..cbf84a289e 100644
--- a/openair2/RRC/NR/cucp_cuup_if.h
+++ b/openair2/RRC/NR/cucp_cuup_if.h
@@ -30,7 +30,9 @@
 
 struct e1ap_bearer_setup_req_s;
 struct e1ap_bearer_setup_resp_s;
+struct e1ap_bearer_release_cmd_s;
 typedef void (*cucp_cuup_bearer_context_setup_func_t)(sctp_assoc_t assoc_id, const struct e1ap_bearer_setup_req_s *req);
+typedef void (*cucp_cuup_bearer_context_release_func_t)(sctp_assoc_t assoc_id, const struct e1ap_bearer_release_cmd_s *cmd);
 
 struct gNB_RRC_INST_s;
 void cucp_cuup_message_transfer_direct_init(struct gNB_RRC_INST_s *rrc);
diff --git a/openair2/RRC/NR/nr_rrc_defs.h b/openair2/RRC/NR/nr_rrc_defs.h
index 92b521cf69..16b7f040ee 100644
--- a/openair2/RRC/NR/nr_rrc_defs.h
+++ b/openair2/RRC/NR/nr_rrc_defs.h
@@ -362,6 +362,7 @@ typedef struct nr_mac_rrc_dl_if_s {
 typedef struct cucp_cuup_if_s {
   cucp_cuup_bearer_context_setup_func_t bearer_context_setup;
   cucp_cuup_bearer_context_setup_func_t bearer_context_mod;
+  cucp_cuup_bearer_context_release_func_t bearer_context_release;
 } cucp_cuup_if_t;
 
 typedef struct nr_rrc_du_container_t {
diff --git a/openair2/RRC/NR/rrc_gNB.c b/openair2/RRC/NR/rrc_gNB.c
index 1534dde669..81455e3549 100644
--- a/openair2/RRC/NR/rrc_gNB.c
+++ b/openair2/RRC/NR/rrc_gNB.c
@@ -2034,8 +2034,6 @@ static void rrc_CU_process_ue_context_release_complete(MessageDef *msg_p)
   }
   gNB_RRC_UE_t *UE = &ue_context_p->ue_context;
 
-  nr_pdcp_remove_UE(UE->rrc_ue_id);
-  newGtpuDeleteAllTunnels(instance, UE->rrc_ue_id);
   rrc_gNB_send_NGAP_UE_CONTEXT_RELEASE_COMPLETE(instance, UE->rrc_ue_id);
   LOG_I(NR_RRC, "removed UE CU UE ID %u/RNTI %04x \n", UE->rrc_ue_id, UE->rnti);
   rrc_delete_ue_data(UE);
@@ -2411,6 +2409,15 @@ void rrc_gNB_process_e1_bearer_context_modif_resp(const e1ap_bearer_modif_resp_t
   }
 }
 
+void rrc_gNB_process_e1_bearer_context_release_cplt(const e1ap_bearer_release_cplt_t *cplt)
+{
+  // there is not really anything to do here as of now
+  // note that we don't check for the UE: it does not exist anymore if the F1
+  // UE context release complete arrived from the DU first, after which we free
+  // the UE context
+  LOG_I(RRC, "UE %d: received bearer release complete\n", cplt->gNB_cu_cp_ue_id);
+}
+
 static void rrc_CU_process_f1_lost_connection(gNB_RRC_INST *rrc, f1ap_lost_connection_t *lc, sctp_assoc_t assoc_id)
 {
   AssertFatal(rrc->du != NULL, "no DU connected, cannot received F1 lost connection\n");
@@ -2694,6 +2701,10 @@ void *rrc_gnb_task(void *args_p) {
         rrc_gNB_process_e1_bearer_context_modif_resp(&E1AP_BEARER_CONTEXT_MODIFICATION_RESP(msg_p));
         break;
 
+      case E1AP_BEARER_CONTEXT_RELEASE_CPLT:
+        rrc_gNB_process_e1_bearer_context_release_cplt(&E1AP_BEARER_CONTEXT_RELEASE_CPLT(msg_p));
+        break;
+
       case NGAP_PAGING_IND:
         rrc_gNB_process_PAGING_IND(msg_p, instance);
         break;
@@ -2845,6 +2856,13 @@ rrc_gNB_generate_RRCRelease(
   deliver_ue_ctxt_release_data_t data = {.rrc = rrc, .release_cmd = &ue_context_release_cmd};
   nr_pdcp_data_req_srb(ctxt_pP->rntiMaybeUEid, DCCH, rrc_gNB_mui++, size, buffer, rrc_deliver_ue_ctxt_release_cmd, &data);
 
+  sctp_assoc_t assoc_id = get_existing_cuup_for_ue(rrc, UE);
+  e1ap_bearer_release_cmd_t cmd = {
+    .gNB_cu_cp_ue_id = UE->rrc_ue_id,
+    .gNB_cu_up_ue_id = UE->rrc_ue_id,
+  };
+  rrc->cucp_cuup.bearer_context_release(assoc_id, &cmd);
+
   /* UE will be freed after UE context release complete */
 }
 
-- 
2.26.2