Implement F1AP RRC Version encoding/decoding in CU&DU

RRC Version is a required IE. Hence, implement the encoder and decoder
for this message. At the DU and CU, read the RRC Version we use and fill
the corresponding field.
Co-authored-by: Robert Schmidt <robert.schmidt@openairinterface.org>

openair2/COMMON/f1ap_messages_types.h

@@ -152,7 +152,10 @@ typedef struct f1ap_setup_req_s {
   // F1_Setup_Req payload
   uint64_t gNB_DU_id;
   char *gNB_DU_name;
-  
+
+  /// rrc version
+  uint8_t rrc_ver[3];
+
   /// number of DU cells available
   uint16_t num_cells_available; //0< num_cells_available <= 512;
   struct {
@@ -188,6 +191,10 @@ typedef struct f1ap_setup_resp_s {
   /// number of DU cells to activate
   uint16_t num_cells_to_activate; //0< num_cells_to_activate <= 512;
   served_cells_to_activate_t cells_to_activate[F1AP_MAX_NB_CELLS];
+
+  /// rrc version
+  uint8_t rrc_ver[3];
+
 } f1ap_setup_resp_t;
 
 typedef struct f1ap_gnb_cu_configuration_update_s {

openair2/F1AP/f1ap_cu_interface_management.c

@@ -204,6 +204,22 @@ int CU_handle_F1_SETUP_REQUEST(instance_t instance, sctp_assoc_t assoc_id, uint3
     }
   }
 
+   /* Handle RRC Version */
+  F1AP_FIND_PROTOCOLIE_BY_ID(F1AP_F1SetupRequestIEs_t, ie, container,
+                             F1AP_ProtocolIE_ID_id_GNB_DU_RRC_Version, true);
+  // Latest RRC Version: "This IE is not used in this release."
+  // BIT_STRING_to_uint8(&ie->value.choice.RRC_Version.latest_RRC_Version);
+  if (ie->value.choice.RRC_Version.iE_Extensions) {
+    F1AP_ProtocolExtensionContainer_10696P228_t *ext =
+        (F1AP_ProtocolExtensionContainer_10696P228_t *)ie->value.choice.RRC_Version.iE_Extensions;
+    if (ext->list.count > 0) {
+      F1AP_RRC_Version_ExtIEs_t *rrcext = ext->list.array[0];
+      OCTET_STRING_t *os = &rrcext->extensionValue.choice.OCTET_STRING_SIZE_3_;
+      DevAssert(os->size == 3);
+      for (int i = 0; i < 3; ++i)
+        req->rrc_ver[i] = os->buf[i];
+    }
+  }
   itti_send_msg_to_task(TASK_RRC_GNB, GNB_MODULE_ID_TO_INSTANCE(instance), message_p);
   
   return 0;
@@ -300,6 +316,36 @@ int CU_send_F1_SETUP_RESPONSE(sctp_assoc_t assoc_id, f1ap_setup_resp_t *f1ap_set
     }
   }
 
+  /* c5. RRC VERSION */
+  asn1cSequenceAdd(out->protocolIEs.list, F1AP_F1SetupResponseIEs_t, ie4);
+  ie4->id = F1AP_ProtocolIE_ID_id_GNB_CU_RRC_Version;
+  ie4->criticality = F1AP_Criticality_reject;
+  ie4->value.present = F1AP_F1SetupResponseIEs__value_PR_RRC_Version;
+  // RRC Version: "This IE is not used in this release."
+  // we put one bit for each byte in rrc_ver that is != 0
+  uint8_t bits = 0;
+  for (int i = 0; i < 3; ++i)
+    bits |= (f1ap_setup_resp->rrc_ver[i] != 0) << i;
+  BIT_STRING_t *bs = &ie4->value.choice.RRC_Version.latest_RRC_Version;
+  bs->buf = calloc(1, sizeof(char));
+  AssertFatal(bs->buf != NULL, "out of memory\n");
+  bs->buf[0] = bits;
+  bs->size = 1;
+  bs->bits_unused = 5;
+
+  F1AP_ProtocolExtensionContainer_10696P228_t *p = (F1AP_ProtocolExtensionContainer_10696P228_t*)calloc(1, sizeof(F1AP_ProtocolExtensionContainer_10696P228_t));    
+  asn1cSequenceAdd(p->list, F1AP_RRC_Version_ExtIEs_t, rrcv_ext);
+  rrcv_ext->id = F1AP_ProtocolIE_ID_id_latest_RRC_Version_Enhanced;
+  rrcv_ext->criticality = F1AP_Criticality_ignore;
+  rrcv_ext->extensionValue.present = F1AP_RRC_Version_ExtIEs__extensionValue_PR_OCTET_STRING_SIZE_3_;
+  OCTET_STRING_t *os = &rrcv_ext->extensionValue.choice.OCTET_STRING_SIZE_3_;
+  os->size = 3;
+  os->buf = malloc(3 * sizeof(*os->buf));
+  AssertFatal(os->buf != NULL, "out of memory\n");
+  for (int i = 0; i < 3; ++i)
+    os->buf[i] = f1ap_setup_resp->rrc_ver[i];
+  ie4->value.choice.RRC_Version.iE_Extensions = (struct F1AP_ProtocolExtensionContainer *)p;
+
   /* encode */
   if (f1ap_encode_pdu(&pdu, &buffer, &len) < 0) {
     LOG_E(F1AP, "Failed to encode F1 setup response\n");

openair2/F1AP/f1ap_du_interface_management.c

@@ -289,14 +289,34 @@ int DU_send_F1_SETUP_REQUEST(sctp_assoc_t assoc_id, f1ap_setup_req_t *setup_req)
   /* mandatory */
   /* c5. RRC VERSION */
   asn1cSequenceAdd(f1Setup->protocolIEs.list, F1AP_F1SetupRequestIEs_t, ie2);
-  ie2->id                        = F1AP_ProtocolIE_ID_id_GNB_DU_RRC_Version;
-  ie2->criticality               = F1AP_Criticality_reject;
-  ie2->value.present             = F1AP_F1SetupRequestIEs__value_PR_RRC_Version;
-  ie2->value.choice.RRC_Version.latest_RRC_Version.buf=calloc(1,sizeof(char));
-  ie2->value.choice.RRC_Version.latest_RRC_Version.buf[0] = 0xe0;
-  ie2->value.choice.RRC_Version.latest_RRC_Version.size = 1;
-  ie2->value.choice.RRC_Version.latest_RRC_Version.bits_unused = 5;
-
+  ie2->id = F1AP_ProtocolIE_ID_id_GNB_DU_RRC_Version;
+  ie2->criticality = F1AP_Criticality_reject;
+  ie2->value.present = F1AP_F1SetupRequestIEs__value_PR_RRC_Version;
+  // RRC Version: "This IE is not used in this release."
+  // we put one bit for each byte in rrc_ver that is != 0
+  uint8_t bits = 0;
+  for (int i = 0; i < 3; ++i)
+    bits |= (setup_req->rrc_ver[i] != 0) << i;
+  BIT_STRING_t *bs = &ie2->value.choice.RRC_Version.latest_RRC_Version;
+  bs->buf = calloc(1, sizeof(char));
+  AssertFatal(bs->buf != NULL, "out of memory\n");
+  bs->buf[0] = bits;
+  bs->size = 1;
+  bs->bits_unused = 5;
+
+  F1AP_ProtocolExtensionContainer_10696P228_t *p = calloc(1, sizeof(F1AP_ProtocolExtensionContainer_10696P228_t));
+  asn1cSequenceAdd(p->list, F1AP_RRC_Version_ExtIEs_t, rrcv_ext);
+  rrcv_ext->id = F1AP_ProtocolIE_ID_id_latest_RRC_Version_Enhanced;
+  rrcv_ext->criticality = F1AP_Criticality_ignore;
+  rrcv_ext->extensionValue.present = F1AP_RRC_Version_ExtIEs__extensionValue_PR_OCTET_STRING_SIZE_3_;
+  OCTET_STRING_t *os = &rrcv_ext->extensionValue.choice.OCTET_STRING_SIZE_3_;
+  os->size = 3;
+  os->buf = malloc(3 * sizeof(*os->buf));
+  AssertFatal(os->buf != NULL, "out of memory\n");
+  for (int i = 0; i < 3; ++i)
+    os->buf[i] = setup_req->rrc_ver[i];
+  ie2->value.choice.RRC_Version.iE_Extensions = (struct F1AP_ProtocolExtensionContainer*)p;
+  
   /* encode */
   if (f1ap_encode_pdu(&pdu, &buffer, &len) < 0) {
     LOG_E(F1AP, "Failed to encode F1 setup request\n");
@@ -343,7 +363,7 @@ int DU_handle_F1_SETUP_RESPONSE(instance_t instance, sctp_assoc_t assoc_id, uint
         AssertFatal(ie->criticality == F1AP_Criticality_ignore,
                     "ie->criticality != F1AP_Criticality_ignore\n");
         AssertFatal(ie->value.present == F1AP_F1SetupResponseIEs__value_PR_GNB_CU_Name,
-                    "ie->value.present != F1AP_F1SetupResponseIEs__value_PR_TransactionID\n");
+                    "ie->value.present != F1AP_F1SetupResponseIEs__value_PR_GNB_CU_Name\n");
         resp.gNB_CU_name = malloc(ie->value.choice.GNB_CU_Name.size+1);
         memcpy(resp.gNB_CU_name, ie->value.choice.GNB_CU_Name.buf, ie->value.choice.GNB_CU_Name.size);
         resp.gNB_CU_name[ie->value.choice.GNB_CU_Name.size] = '\0';
@@ -351,7 +371,21 @@ int DU_handle_F1_SETUP_RESPONSE(instance_t instance, sctp_assoc_t assoc_id, uint
         break;
 
       case F1AP_ProtocolIE_ID_id_GNB_CU_RRC_Version:
-        LOG_D(F1AP, "F1AP: Received GNB-CU-RRC-Version, ignoring\n");
+        AssertFatal(ie->criticality == F1AP_Criticality_reject,
+                    "ie->criticality != F1AP_Criticality_reject\n");
+        AssertFatal(ie->value.present == F1AP_F1SetupResponseIEs__value_PR_RRC_Version,
+                    "ie->value.present != F1AP_F1SetupResponseIEs__value_PR_RRC_Version\n");
+        // RRC Version: "This IE is not used in this release."
+        if(ie->value.choice.RRC_Version.iE_Extensions) {
+          F1AP_ProtocolExtensionContainer_10696P228_t *ext =
+              (F1AP_ProtocolExtensionContainer_10696P228_t *)ie->value.choice.RRC_Version.iE_Extensions;
+          if(ext->list.count > 0){
+            F1AP_RRC_Version_ExtIEs_t *rrcext = ext->list.array[0];
+            OCTET_STRING_t *os = &rrcext->extensionValue.choice.OCTET_STRING_SIZE_3_;
+            for (int i = 0; i < 3; i++)
+              resp.rrc_ver[i] = os->buf[i];
+          }
+        }
         break;
 
       case F1AP_ProtocolIE_ID_id_Cells_to_be_Activated_List: {

openair2/GNB_APP/gnb_config.c

@@ -1175,6 +1175,9 @@ static f1ap_setup_req_t *RC_read_F1Setup(uint64_t id,
     sys_info->sib1_length = (enc_rval.encoded + 7) / 8;
   }
 
+  int num = read_version(TO_STRING(NR_RRC_VERSION), &req->rrc_ver[0], &req->rrc_ver[1], &req->rrc_ver[2]);
+  AssertFatal(num == 3, "could not read RRC version string %s\n", TO_STRING(NR_RRC_VERSION));
+
   return req;
 }
 

openair2/LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c

@@ -52,6 +52,7 @@ static bool check_plmn_identity(const f1ap_plmn_t *check_plmn, const f1ap_plmn_t
 void f1_setup_response(const f1ap_setup_resp_t *resp)
 {
   LOG_I(MAC, "received F1 Setup Response from CU %s\n", resp->gNB_CU_name);
+  LOG_I(MAC, "CU uses RRC version %d.%d.%d\n", resp->rrc_ver[0], resp->rrc_ver[1], resp->rrc_ver[2]);
 
   if (resp->num_cells_to_activate == 0) {
     LOG_W(NR_MAC, "no cell to activate: cell remains blocked\n");

openair2/LAYER2/NR_MAC_gNB/mac_rrc_ul_direct.c

@@ -61,6 +61,7 @@ static void f1_setup_request_direct(const f1ap_setup_req_t *req)
       }
     }
   }
+  memcpy(f1ap_msg->rrc_ver, req->rrc_ver, sizeof(req->rrc_ver));
 
   itti_send_msg_to_task(TASK_RRC_GNB, 0, msg);
 }

openair2/LAYER2/NR_MAC_gNB/mac_rrc_ul_f1ap.c

@@ -93,6 +93,7 @@ static void f1_setup_request_f1ap(const f1ap_setup_req_t *req)
       }
     }
   }
+  memcpy(f1ap_setup->rrc_ver, req->rrc_ver, sizeof(req->rrc_ver));
 
   F1AP_DU_REGISTER_REQ(msg).net_config = read_DU_IP_config(&RC.nrmac[0]->eth_params_n);
 

openair2/RRC/NR/rrc_gNB_du.c

@@ -141,6 +141,7 @@ void rrc_gNB_process_f1_setup_req(f1ap_setup_req_t *req, sctp_assoc_t assoc_id)
     }
   }
   LOG_I(RRC, "Accepting DU %ld (%s), sending F1 Setup Response\n", req->gNB_DU_id, req->gNB_DU_name);
+  LOG_I(RRC, "DU uses RRC version %u.%u.%u\n", req->rrc_ver[0], req->rrc_ver[1], req->rrc_ver[2]);
 
   // we accept the DU
   nr_rrc_du_container_t *du = calloc(1, sizeof(*du));
@@ -167,8 +168,13 @@ void rrc_gNB_process_f1_setup_req(f1ap_setup_req_t *req, sctp_assoc_t assoc_id)
       .nr_cellid = cell_info->nr_cellid,
       .nrpci = cell_info->nr_pci,
       .num_SI = 0,
-  };
-  f1ap_setup_resp_t resp = {.transaction_id = req->transaction_id, .num_cells_to_activate = 1, .cells_to_activate[0] = cell};
+  };  
+
+  f1ap_setup_resp_t resp = {.transaction_id = req->transaction_id,
+                            .num_cells_to_activate = 1,
+                            .cells_to_activate[0] = cell};
+  int num = read_version(TO_STRING(NR_RRC_VERSION), &resp.rrc_ver[0], &resp.rrc_ver[1], &resp.rrc_ver[2]);
+  AssertFatal(num == 3, "could not read RRC version string %s\n", TO_STRING(NR_RRC_VERSION));
   if (rrc->node_name != NULL)
     resp.gNB_CU_name = strdup(rrc->node_name);
   rrc->mac_rrc.f1_setup_response(assoc_id, &resp);