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Add NGAP Handover Command decoder and RRC handler on source gNB

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* add NG Handover Command message decoder
* process in RRC: encode RRCReconfiguration message
  from the received HandoverCommandMessage
* trigger RRCReconfiguration for handover

Co-authored-by: batuhan duyuler <batuhan.duyuler@firecell.io>
This commit is contained in:
Guido Casati
2025-09-18 11:34:30 +02:00
co-authored by batuhan duyuler
parent 6fd02ee7e8
commit f66524879d
14 changed files with 269 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
openair2/COMMON/ngap_messages_def.h
+1
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@@ -85,6 +85,7 @@ MESSAGE_DEF(NGAP_PDUSESSION_MODIFY_REQ , MESSAGE_PRIORITY_MED, ngap_pd
MESSAGE_DEF(NGAP_PDUSESSION_RELEASE_COMMAND , MESSAGE_PRIORITY_MED, ngap_pdusession_release_command_t , ngap_pdusession_release_command)
MESSAGE_DEF(NGAP_UE_CONTEXT_RELEASE_COMMAND, MESSAGE_PRIORITY_MED, ngap_ue_release_command_t , ngap_ue_release_command)
MESSAGE_DEF(NGAP_HANDOVER_REQUEST, MESSAGE_PRIORITY_MED, ngap_handover_request_t, ngap_handover_request)
MESSAGE_DEF(NGAP_HANDOVER_COMMAND, MESSAGE_PRIORITY_MED, ngap_handover_command_t, ngap_handover_command)
/* NGAP <-> RRC messages (can be initiated either by MME or gNB) */
MESSAGE_DEF(NGAP_UE_CONTEXT_RELEASE_REQ , MESSAGE_PRIORITY_MED, ngap_ue_release_req_t , ngap_ue_release_req)
openair2/COMMON/ngap_messages_types.h
+32
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@@ -69,6 +69,7 @@
#define NGAP_HANDOVER_FAILURE(mSGpTR) (mSGpTR)->ittiMsg.ngap_handover_failure
#define NGAP_HANDOVER_REQUEST(mSGpTR) (mSGpTR)->ittiMsg.ngap_handover_request
#define NGAP_HANDOVER_REQUEST_ACKNOWLEDGE(mSGpTR) (mSGpTR)->ittiMsg.ngap_handover_request_ack
#define NGAP_HANDOVER_COMMAND(mSGpTR) (mSGpTR)->ittiMsg.ngap_handover_command
#define NGAP_UE_CONTEXT_RELEASE_REQ(mSGpTR) (mSGpTR)->ittiMsg.ngap_ue_release_req
#define NGAP_PDUSESSION_RELEASE_COMMAND(mSGpTR) (mSGpTR)->ittiMsg.ngap_pdusession_release_command
@@ -648,6 +649,37 @@ typedef struct {
byte_array_t target2source;
} ngap_handover_request_ack_t;
/* 9.3.4.10 3GPP TS 38.413 */
typedef struct {
// QoS Flow to be Forwarded List
uint8_t nb_of_qos_flow;
pdusession_associate_qosflow_t qos_setup_list[QOSFLOW_MAX_VALUE];
// UL Forwarding UP TNL Information
uint32_t gtp_teid;
transport_layer_addr_t gNB_addr;
} ho_command_transfer_t;
typedef struct {
// PDU Session ID (M)
uint8_t pdusession_id;
// Handover Command Transfer (M)
ho_command_transfer_t ho_command_transfer;
} pdusession_resource_handover_t;
typedef struct {
// AMF UE NGAP ID
uint64_t amf_ue_ngap_id;
// RAN UE NGAP ID
uint32_t gNB_ue_ngap_id;
// Handover Type
ho_type_t handoverType;
// PDU Session Resource Handover List
uint8_t nb_of_pdusessions;
pdusession_resource_handover_t pdu_sessions[NGAP_MAX_PDU_SESSION];
// Target to Source Transparent Container
byte_array_t handoverCommand;
} ngap_handover_command_t;
typedef struct ngap_ue_cap_info_ind_s {
uint32_t gNB_ue_ngap_id;
byte_array_t ue_radio_cap;
openair2/RRC/NR/MESSAGES/asn1_msg.c
+39
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@@ -64,6 +64,10 @@
#include "NR_LogicalChannelConfig.h"
#include "NR_PDCP-Config.h"
#include "NR_MAC-CellGroupConfig.h"
#include "NR_HandoverPreparationInformation.h"
#include "NR_HandoverCommand.h"
#include "NR_HandoverCommand-IEs.h"
#include "NR_AS-Config.h"
#include "NR_SecurityModeCommand.h"
#include "NR_CipheringAlgorithm.h"
#include "NR_RRCReconfiguration-IEs.h"
@@ -1221,6 +1225,41 @@ void fill_removal_lists_from_source_measConfig(NR_MeasConfig_t *currentMC, byte_
}
}
int doRRCReconfiguration_from_HandoverCommand(byte_array_t *ba, const byte_array_t handoverCommand)
{
// Decode Handover Command
NR_HandoverCommand_t *hoCommand = NULL;
asn_dec_rval_t dec_rval = uper_decode_complete(NULL, &asn_DEF_NR_HandoverCommand, (void **)&hoCommand, handoverCommand.buf, handoverCommand.len);
if (dec_rval.code != RC_OK && dec_rval.consumed == 0) {
LOG_E(NR_RRC, "Can not decode Handover Command!\n");
return -1;
}
// Prepare DL DCCH message for RRCReconfiguration
NR_DL_DCCH_Message_t dl_dcch_msg = {0};
asn_enc_rval_t enc_rval;
dl_dcch_msg.message.present = NR_DL_DCCH_MessageType_PR_c1;
asn1cCalloc(dl_dcch_msg.message.choice.c1, c1);
c1->present = NR_DL_DCCH_MessageType__c1_PR_rrcReconfiguration;
asn1cCalloc(c1->choice.rrcReconfiguration, rrcReconf);
// Decode RRCReconfiguration from handoverCommandMessage
OCTET_STRING_t *ho = &hoCommand->criticalExtensions.choice.c1->choice.handoverCommand->handoverCommandMessage;
uper_decode_complete(NULL, &asn_DEF_NR_RRCReconfiguration, (void **)&rrcReconf, ho->buf, ho->size);
if (LOG_DEBUGFLAG(DEBUG_ASN1))
xer_fprint(stdout, &asn_DEF_NR_DL_DCCH_Message, (void *)&dl_dcch_msg);
// Encode DL DCCH message in buffer
enc_rval = uper_encode_to_buffer(&asn_DEF_NR_DL_DCCH_Message, NULL, &dl_dcch_msg, ba->buf, ba->len);
AssertFatal(enc_rval.encoded > 0, "ASN1 message encoding failed (%s, %lu)!\n", enc_rval.failed_type->name, enc_rval.encoded);
ASN_STRUCT_FREE_CONTENTS_ONLY(asn_DEF_NR_DL_DCCH_Message, &dl_dcch_msg);
ASN_STRUCT_FREE(asn_DEF_NR_HandoverCommand, hoCommand);
return ((enc_rval.encoded + 7) / 8);
}
byte_array_t get_HandoverCommandMessage(nr_rrc_reconfig_param_t *params)
{
// Encode RRCReconfiguration to buffer
openair2/RRC/NR/MESSAGES/asn1_msg.h
+1
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@@ -165,5 +165,6 @@ int do_NR_Paging(uint8_t Mod_id, uint8_t *buffer, uint32_t tmsi);
byte_array_t get_HandoverPreparationInformation(nr_rrc_reconfig_param_t *params, int scell_pci);
byte_array_t get_HandoverCommandMessage(nr_rrc_reconfig_param_t *params);
void fill_removal_lists_from_source_measConfig(NR_MeasConfig_t *measConfig, byte_array_t prep_info);
int doRRCReconfiguration_from_HandoverCommand(byte_array_t *ba, byte_array_t handoverCommand);
#endif /* __RRC_NR_MESSAGES_ASN1_MSG__H__ */
openair2/RRC/NR/rrc_gNB.c
+6
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@@ -98,6 +98,7 @@
#include "NR_DL-DCCH-Message.h"
#include "ds/byte_array.h"
#include "alg/find.h"
#include "NR_HandoverCommand.h"
#ifdef E2_AGENT
#include "openair2/E2AP/RAN_FUNCTION/O-RAN/ran_func_rc_extern.h"
@@ -2949,6 +2950,11 @@ void *rrc_gnb_task(void *args_p) {
rrc_gNB_free_Handover_Request(&NGAP_HANDOVER_REQUEST(msg_p)); // Free transfered NG message
break;
case NGAP_HANDOVER_COMMAND:
rrc_gNB_process_HandoverCommand(RC.nrrrc[instance], &NGAP_HANDOVER_COMMAND(msg_p));
rrc_gNB_free_Handover_Command(&NGAP_HANDOVER_COMMAND(msg_p)); // Free transfered NG message
break;
default:
LOG_E(NR_RRC, "[gNB %ld] Received unexpected message %s\n", instance, msg_name_p);
break;
openair2/RRC/NR/rrc_gNB_NGAP.c
+28
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@@ -39,6 +39,9 @@
#include <arpa/inet.h>
#include "E1AP_ConfidentialityProtectionIndication.h"
#include "E1AP_IntegrityProtectionIndication.h"
#include "NR_UE-CapabilityRAT-ContainerList.h"
#include "NR_HandoverCommand.h"
#include "NR_HandoverCommand-IEs.h"
#include "NGAP_CauseRadioNetwork.h"
#include "NGAP_Dynamic5QIDescriptor.h"
#include "NGAP_GTPTunnel.h"
@@ -1161,6 +1164,31 @@ void rrc_gNB_free_Handover_Request(ngap_handover_request_t *msg)
free(msg->mobility_restriction);
}
/** @brief Process NG Handover Command on Source gNB */
void rrc_gNB_process_HandoverCommand(gNB_RRC_INST *rrc, const ngap_handover_command_t *msg)
{
rrc_gNB_ue_context_t *ue_context_p = rrc_gNB_get_ue_context(rrc, msg->gNB_ue_ngap_id);
if (ue_context_p == NULL) {
LOG_W(NR_RRC, "Unknown UE context associated to gNB_ue_ngap_id (%u)\n", msg->gNB_ue_ngap_id);
return;
}
gNB_RRC_UE_t *UE = &ue_context_p->ue_context;
uint8_t buffer[NR_RRC_BUF_SIZE];
byte_array_t ba = {.buf = buffer, .len = sizeof(buffer)};
int enc = doRRCReconfiguration_from_HandoverCommand(&ba, msg->handoverCommand);
DevAssert(enc > 0);
rrc_gNB_trigger_reconfiguration_for_handover(rrc, UE, buffer, enc);
LOG_A(NR_RRC, "Send reconfiguration (HO Command) to UE %u/RNTI %04x\n", UE->rrc_ue_id, UE->rnti);
}
void rrc_gNB_free_Handover_Command(ngap_handover_command_t *msg)
{
free_byte_array(msg->handoverCommand);
}
/*
* Process the NG command NGAP_UE_CONTEXT_RELEASE_COMMAND, sent by AMF.
* The gNB should remove all pdu session, NG context, and other context of the UE.
openair2/RRC/NR/rrc_gNB_NGAP.h
+3
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@@ -101,4 +101,7 @@ void rrc_gNB_free_Handover_Request(ngap_handover_request_t *msg);
void rrc_gNB_send_NGAP_HANDOVER_REQUEST_ACKNOWLEDGE(gNB_RRC_INST *rrc, gNB_RRC_UE_t *UE, byte_array_t ho_command);
void rrc_gNB_process_HandoverCommand(gNB_RRC_INST *rrc, const ngap_handover_command_t *msg);
void rrc_gNB_free_Handover_Command(ngap_handover_command_t *msg);
#endif
openair2/RRC/NR/rrc_gNB_mobility.c
+2 -1
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@@ -231,7 +231,8 @@ static void rrc_deliver_ue_ctxt_modif_req(void *deliver_pdu_data, ue_id_t ue_id,
data->modification_req->rrc_container = &ba;
data->rrc->mac_rrc.ue_context_modification_request(data->assoc_id, data->modification_req);
}
static void rrc_gNB_trigger_reconfiguration_for_handover(gNB_RRC_INST *rrc, gNB_RRC_UE_t *ue, uint8_t *rrc_reconf, int rrc_reconf_len)
void rrc_gNB_trigger_reconfiguration_for_handover(gNB_RRC_INST *rrc, gNB_RRC_UE_t *ue, uint8_t *rrc_reconf, int rrc_reconf_len)
{
f1_ue_data_t ue_data = cu_get_f1_ue_data(ue->rrc_ue_id);
openair2/RRC/NR/rrc_gNB_mobility.h
+2
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@@ -89,4 +89,6 @@ void nr_rrc_trigger_n2_ho(gNB_RRC_INST *rrc,
int serving_pci,
const nr_neighbour_cell_t *neighbour_config);
void rrc_gNB_trigger_reconfiguration_for_handover(gNB_RRC_INST *rrc, gNB_RRC_UE_t *ue, uint8_t *rrc_reconf, int rrc_reconf_len);
#endif /* RRC_GNB_MOBILITY_H_ */