From 23a865db77d84121f055e21b8caf73b60f47b57b Mon Sep 17 00:00:00 2001
From: Xin Zhe Khooi <khooixz@comp.nus.edu.sg>
Date: Tue, 21 May 2024 02:46:35 +0000
Subject: [PATCH] Implement DU F1 Reset handlers

---
 .../LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c    | 38 ++++++++++++++++++-
 openair2/LAYER2/NR_MAC_gNB/mac_rrc_ul_f1ap.c  |  6 ++-
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/openair2/LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c b/openair2/LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c
index d47392491b..aac03be132 100644
--- a/openair2/LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c
+++ b/openair2/LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c
@@ -95,10 +95,44 @@ static bool check_plmn_identity(const f1ap_plmn_t *check_plmn, const f1ap_plmn_t
   return plmn->mcc == check_plmn->mcc && plmn->mnc_digit_length == check_plmn->mnc_digit_length && plmn->mnc == check_plmn->mnc;
 }
 
+static void du_clear_all_ue_states()
+{
+  gNB_MAC_INST *mac = RC.nrmac[0];
+  NR_SCHED_LOCK(&mac->sched_lock);
+
+  NR_UE_info_t *UE = *mac->UE_info.list;
+
+  instance_t f1inst = get_f1_gtp_instance();
+
+  while (UE != NULL) {
+    int rnti = UE->rnti;
+    nr_mac_release_ue(mac, rnti);
+    // free all F1 contexts
+    if (du_exists_f1_ue_data(rnti))
+      du_remove_f1_ue_data(rnti);
+    newGtpuDeleteAllTunnels(f1inst, rnti);
+    UE = *mac->UE_info.list;
+  }
+  NR_SCHED_UNLOCK(&mac->sched_lock);
+}
+
 void f1_reset_cu_initiated(const f1ap_reset_t *reset)
 {
-  (void) reset;
-  AssertFatal(false, "%s() not implemented yet\n", __func__);
+  LOG_I(MAC, "F1 Reset initiated by CU\n");
+
+  f1ap_reset_ack_t ack = {0};
+  if(reset->reset_type == F1AP_RESET_ALL) {
+    du_clear_all_ue_states();
+    ack = (f1ap_reset_ack_t) {
+      .transaction_id = reset->transaction_id
+    };
+  } else {
+    // reset->reset_type == F1AP_RESET_PART_OF_F1_INTERFACE
+    AssertFatal(1==0, "Not implemented yet\n");
+  }
+
+  gNB_MAC_INST *mac = RC.nrmac[0];
+  mac->mac_rrc.f1_reset_acknowledge(&ack);
 }
 
 void f1_reset_acknowledge_du_initiated(const f1ap_reset_ack_t *ack)
diff --git a/openair2/LAYER2/NR_MAC_gNB/mac_rrc_ul_f1ap.c b/openair2/LAYER2/NR_MAC_gNB/mac_rrc_ul_f1ap.c
index 4d716e9fb7..742f85c390 100644
--- a/openair2/LAYER2/NR_MAC_gNB/mac_rrc_ul_f1ap.c
+++ b/openair2/LAYER2/NR_MAC_gNB/mac_rrc_ul_f1ap.c
@@ -61,8 +61,10 @@ static void f1_reset_du_initiated_f1ap(const f1ap_reset_t *reset)
 
 static void f1_reset_acknowledge_cu_initiated_f1ap(const f1ap_reset_ack_t *ack)
 {
-  (void) ack;
-  AssertFatal(false, "%s() not implemented yet\n", __func__);
+  MessageDef *msg = itti_alloc_new_message(TASK_MAC_GNB, 0, F1AP_RESET_ACK);
+  f1ap_reset_ack_t *f1ap_msg = &F1AP_RESET_ACK(msg);
+  *f1ap_msg = *ack;
+  itti_send_msg_to_task(TASK_DU_F1, 0, msg);
 }
 
 static void f1_setup_request_f1ap(const f1ap_setup_req_t *req)