NR UE: add neighboring cell measurements and measurement report of event A3
This is a rework of MR !2385 (closed), the goal is to add neighboring cell
measurements and measurement report of event A3 for NR UE.
This MR was tested with:
- 3rd-party gNB
- 2 OAI-gNB-DUs
The neighboring cell measurements and measurement report of event A3 for OAI-UE
are working as expected.
Refactor key derivation logic to properly handle Next Hop (NH) chain
synchronization according to 3GPP TS 33.501 specifications for both RRC
Reestablishment and Master Key Update procedures.
Changes in rrc_gNB.c:
- Clarify key derivation in rrc_gNB_generate_RRCReestablishment by explicitly
selecting base key (NH or KgNB) based on nh_ncc value
- Add comment explaining vertical vs horizontal derivation logic
Changes in rrc_UE.c:
Refactored the NH chain synchronization and key derivation code to match
TS 33.501 terminology:
- nr_sync_nh_chain(): Common helper to synchronize NH parameter chain per
TS 33.501 Annex A.10, supporting both Master Key Update and RRC Reestablishment
procedures
- nr_derive_kgnb_horizontal(): Derive KNG-RAN* from current KgNB when NCC values
match (horizontal derivation per TS 33.501 A.11/A.12)
- nr_derive_kgnb_vertical(): Derive KNG-RAN* from synchronized NH after NH chain
sync (vertical derivation per TS 33.501 A.11/A.12)
- nr_update_kgnb_from_ncc(): Unified function implementing TS 33.501 6.9.2.3.4
logic for updating KgNB based on received nextHopChainingCount
- Refactor as_security_key_update(): Use new nr_update_kgnb_from_ncc() helper
function for cleaner, more maintainable code
- Fix nr_rrc_ue_process_rrcReestablishment(): Properly handle received
nextHopChainingCount and update KgNB using unified helper function
- Replaced the previous nr_rrc_nh_update() helper with these functions to
improve clarity and alignment with the specification.
- Add debug logging for key derivation process
Key NAS deriver utils:
- update derive_kgnb documentation and protect input keys with const attribute
Closes#857
These logs are very helpful to identify cell configuration
changes in MAC/PHY, for monitoring purposes, and to rapidly
signal integrity failures during re-establishment.
Refactor key derivation logic to properly handle Next Hop (NH) chain
synchronization according to 3GPP TS 33.501 specifications for both
RRC Reestablishment and Master Key Update procedures.
Changes in rrc_gNB.c:
- Clarify key derivation in rrc_gNB_generate_RRCReestablishment by
explicitly selecting base key (NH or KgNB) based on nh_ncc value
- Add comment explaining vertical vs horizontal derivation logic
Changes in rrc_UE.c:
- Add nr_sync_nh_chain(): Common helper to synchronize NH parameter
chain per TS 33.501 Annex A.10, supporting both Master Key Update
and RRC Reestablishment procedures
- Add nr_derive_kgnb_horizontal(): Derive KNG-RAN* from current KgNB
when NCC values match (horizontal derivation per TS 33.501 A.11/A.12)
- Add nr_derive_kgnb_vertical(): Derive KNG-RAN* from synchronized NH
after NH chain sync (vertical derivation per TS 33.501 A.11/A.12)
- Add nr_update_kgnb_from_ncc(): Unified function implementing TS 33.501
6.9.2.3.4 logic for updating KgNB based on received nextHopChainingCount
- Refactor as_security_key_update(): Use new nr_update_kgnb_from_ncc()
helper function for cleaner, more maintainable code
- Fix nr_rrc_ue_process_rrcReestablishment(): Properly handle received
nextHopChainingCount and update KgNB using unified helper function
- Add debug logging for key derivation process
Key NAS deriver utils:
- update derive_kgnb documentation and protect input keys with const attribute
NR UE: calculate TA based on SIB19 information in NTN mode, if autonomous TA is not enabled
To achieve the goal, the hyper frame number (HFN) is introduced at the NR UE
PHY, MAC and RRC layers.
Besides this, we also implemented an orbit propagation to improve the accuracy
of N_UE_TA_adj, and a fix to keep the N_TA from RAR and MAC CE.
Fixes#981
In case of Handover, NTNconfig sent in RRCreconfiguration triggering handover contains epoch time wrt
timing of Target cell. NTNconfig in RRC needs to be processed only after timing is acquired on the target cell
In case of Target cell, epoch time is the sfn nearest to the frame timing of the target cell.
PDU Session Release
This MR implements end-to-end PDU Session Release functionality
according to 3GPP TS 38.413 and TS 38.331 specifications.
Reason for Change Previous implementation had incomplete and wrongly
places tunnel cleanup during PDU session release. UP cleanup shall be
done at CUUP, RRCReconfiguration shall be sent after retrieval of
updated CellGroupConfig from the DU. This implies F1 and E1 exchanges
during PDU session release procedure.
Major Changes:
1. RRC PDU Session Release: DRBs and PDU session teardown in NGAP PDU
Session Release Response callback
- Helper Functions: Introduced rm_pduSession,
find_drb_by_pdusession_id and rm_drbs() helpers to locate and clean
up DRBs linked to a specific PDU session
- Targeted Cleanup: RRC PDU Session and per-session DRB removal in
rrc_gNB_send_NGAP_PDUSESSION_RELEASE_RESPONSE()
- Status Cleanup: Removed unused PDU_SESSION_STATUS_RELEASED status
2. RRC PDU Session Release: Refactor
rrc_gNB_process_NGAP_PDUSESSION_RELEASE_COMMAND
- Any PDU session in the pdusession_release_params list that is
present in the RRC list can be set to release, regardless of its
status
- Function Signature Update: Updated function signature and other
minor changes
- Response Handling: rrc_gNB_send_NGAP_PDUSESSION_RELEASE_RESPONSE is
sent upon completion of RRCReconfiguration
3. RRC PDU Session Release: add missing procedures E1AP Integration:
- Populates E1AP Bearer Modification for each to be released session
- PDCP Enhancement: Added nr_pdcp_release_drbs() to remove all DRBs
linked to a given PDU session in CUUP
- GTP-U Cleanup: GTP tunnel teardown handled in CUUP
e1_bearer_context_modif() using correct F1 or N3 GTP instance
4. NR PDCP/GTP:
- Enhanced Tunnel Deletion Logic: Separate handling for N3 tunnels (1
per PDU session) and F1-U tunnels (1 per DRB)
- New PDCP API Function: Added nr_pdcp_get_drb_ids_for_pdusession()
function to retrieve all DRB IDs associated with a specific PDU
session
5. RRC PDU Session Release: F1AP-based UE Context Modification:
- Replaced direct RRC message transfer with F1AP UE Context
Modification Request for proper retrieval from DU
- Cell Group Configuration: handling of updated CellGroupConfig from
DU ensures DRB release at CU
6. Docs and testing:
- Added PDU session add/remove test cases to 25 PRB RFSIM pipeline
- Documentation: Added PDU Session Release sequence diagram
- Telnet Commands: Added ci command to trigger NGAP PDU Session
Release and ciUE command to trigger establishment of a new PDU
Session
7. Additional fixes:
- UE RLC Management: ensure release of RLC entities
- Unify NG delay control before calling the RRC NGAP handler, for both
Setup and Release
8. Code Cleanup: Cleaned up unused GTP teardown functions.
Closes#867
This commit refactors the SDAP entity QoS flow to DRB mapping functionality
to improve code organization and enhance maintainability.
Key changes:
- Split nr_sdap_qfi2drb_map_update into focused functions:
* nr_sdap_add_qos_flows_to_drb: handles QFI addition to DRB
* nr_sdap_rm_qos_flows_from_drb: handles QFI removal from DRB
* nr_sdap_ue_control_pdu_config: handles UE control PDU generation
- Consolidate add/modify logic into reusable nr_sdap_addmod_entity function
- Remove entity existence checking and updating from new_nr_sdap_entity:
this function should only add SDAP entities
- Improve function separation of concerns: do SDAP entity add or update
separately and improve modularity by splitting operations in self
contained functions
- At SDAP creation, do only add of QFI to DRB mapping
- rename new_nr_sdap_entity to nr_sdap_add_entity for function naming consinstency
* use get_sdap_Config to process sdap_Config
* move SDAP config logic to the scope where it is relevant
* add SDAP entity direcly in RRC, not from PDCP
* replaced nr_pdcp_add_drbs with single add_drb call: it was no longer
efficient to keep it in the new logic. The addMod list can be looped directly in RRC.
* add specific function to add bearers from addMod list in E1, NSA, and UE
OAI UE: add shared RSRP Table 10.1.6.1-1 mapping function to helpers and adopt
it RRC UE
- Add to common/utils/nr/nr_common remove from NR_MAC_UE/nr_ue_procedures.c
- Adopt in asn1_msg.c for MeasurementReport: this solves the following possible
assert:
Assertion (enc_rval.encoded > 0) failed!
In do_nrMeasurementReport_SA() /oai-ran/openair2/RRC/NR/MESSAGES/asn1_msg.c:898
ASN1 message encoding failed (MeasResultServMOList, 18446744073709551615)!
Motivation: unify RSRP-to-index mapping across layers and fix NR RRC
MeasurementReport encoding failures due to out-of-range values by reusing the
validated mapping.
Note: NR_RSRP-Range.c constraint: /* (0..127) */
Also refactored MeasurementReport to improve the code.
- Simplify do_nrMeasurementReport_SA API (encoder allocates local report)
- Adopt asn1cCalloc consistently
- Minor init cleanup for UL_DCCH message struct
- Add to common/utils/nr/nr_common remove from NR_MAC_UE/nr_ue_procedures.c
- Adopt in asn1_msg.c for MeasurementReport: this solves the following assert:
Assertion (enc_rval.encoded > 0) failed!
In do_nrMeasurementReport_SA() /oai-ran/openair2/RRC/NR/MESSAGES/asn1_msg.c:898
ASN1 message encoding failed (MeasResultServMOList, 18446744073709551615)!
Motivation: unify RSRP-to-index mapping across layers and fix NR RRC MeasurementReport
encoding failures due to out-of-range values by reusing the validated mapping.
Note NR_RSRP-Range.c constraint:
{ APC_CONSTRAINED, 7, 7, 0, 127 } /* (0..127) */
Remove NR L2 simulator code from UE
This MR removes NR (SA and NSA) L2 simulator from the codebase. The code, at
least at the UE side, was done at a time where there was no clear L2/L1 split
leading to a complex implementation that never worked as expected. The L2
simulator has been broken and removed from testing for long time and, once it
needs to be revived, it would require a complete new implementation.
Fix OAI UE memory leaks
Fix 1: Replaced asn1cFreeStruc with ASN_STRUCT_FREE in MAC layer to properly
free nested ASN.1 structures in cell group configuration.
Fix 2: Removed premature nullification of dedicatedNAS_Message->buf in
dlInformationTransfer processing to allow proper ASN.1 cleanup.
Fix 3: Fixed memory ownership in nr_rrc_process_dedicatedNAS_MessageList by
copying OCTET_STRING data instead of transferring ownership, preventing
ASN.1 cleanup from losing track of allocated memory
Closes#828
- Remove unnecessary NULL assignment for dedicatedNAS_Message->buf
- The original buffer is copied and transfered to NAS, so it can be properly freed by ASN.1 structure cleanup
Root cause: Code was nullifying dedicatedNAS_Message->buf pointer before ASN.1 cleanup could free the original allocation, causing the leak from OCTET_STRING_decode_uper.
AddressSanitizer leak trace (FIXED):
Direct leak of 119 byte(s) in 3 object(s) allocated from:
/#0 0x7ec2a42b4c38 in __interceptor_realloc
/#1 0x555fade852e0 in OCTET_STRING_decode_uper
/#9 0x555fadb48b11 in nr_rrc_ue_decode_dcch.
The leak was caused by improper memory ownership handling in the
dedicatedNAS_MessageList processing. The function was transferring
buffer ownership to NAS messages and then preventing ASN.1 cleanup
from freeing the original allocations by setting
list.count = 0, causing a memory leak.
Leak trace:
Direct leak of 40 byte(s) in 1 object(s) allocated from:
/#0 0x7f2ce3ab4a57 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
/#1 0x567907083f0f in OCTET_STRING_decode_uper /cmake_targets/ran_build/build/openair2/RRC/LTE/MESSAGES/OCTET_STRING_uper.c:89
/#2 0x5679070ed5e6 in SET_OF_decode_uper /cmake_targets/ran_build/build/openair2/RRC/NR/MESSAGES/constr_SET_OF_uper.c:70
/#3 0x56790707b6dc in SEQUENCE_decode_uper /cmake_targets/ran_build/build/openair2/RRC/LTE/MESSAGES/constr_SEQUENCE_uper.c:118
/#4 0x56790707b6dc in SEQUENCE_decode_uper /cmake_targets/ran_build/build/openair2/RRC/LTE/MESSAGES/constr_SEQUENCE_uper.c:118
/#5 0x56790709a403 in CHOICE_decode_uper /cmake_targets/ran_build/build/openair2/RRC/LTE/MESSAGES/constr_CHOICE_uper.c:84
/#6 0x56790707b6dc in SEQUENCE_decode_uper /cmake_targets/ran_build/build/openair2/RRC/LTE/MESSAGES/constr_SEQUENCE_uper.c:118
/#7 0x56790709a403 in CHOICE_decode_uper /cmake_targets/ran_build/build/openair2/RRC/LTE/MESSAGES/constr_CHOICE_uper.c:84
/#8 0x56790709a403 in CHOICE_decode_uper /cmake_targets/ran_build/build/openair2/RRC/LTE/MESSAGES/constr_CHOICE_uper.c:84
/#9 0x56790707b6dc in SEQUENCE_decode_uper /cmake_targets/ran_build/build/openair2/RRC/LTE/MESSAGES/constr_SEQUENCE_uper.c:118
/#10 0x56790708b5f1 in uper_decode /cmake_targets/ran_build/build/openair2/RRC/LTE/MESSAGES/uper_decoder.c:83
/#11 0x567906d44b4b in nr_rrc_ue_decode_dcch /openair2/RRC/NR_UE/rrc_UE.c:2212
/#12 0x567906d520a3 in rrc_nrue /openair2/RRC/NR_UE/rrc_UE.c:2615
/#13 0x567906d5f77e in rrc_nrue_task /openair2/RRC/NR_UE/rrc_UE.c:2501
/#14 0x7f2ce2494ac2 in start_thread nptl/pthread_create.c:442
Fix:
- Copy OCTET_STRING data instead of transferring ownership
- Allow ASN.1 cleanup to properly free original allocations
This fixes the leak that occurred during rrcReconfiguration
message processing when dedicatedNAS_MessageList was present.
Closes#828
- Replace asn1cFreeStruc with ASN_STRUCT_FREE in MAC layer cleanup
- Fixes improper memory management of NR_CellGroupConfig structures
Root cause: asn1cFreeStruc only calls ASN_STRUCT_RESET + free(), which doesn't properly free nested ASN.1 allocations. ASN_STRUCT_FREE frees all nested structures completely.
AddressSanitizer leak trace:
Direct leak of 288 byte(s) in 1 object(s) allocated from:
/#0 0x7fb72bab4a57 in __interceptor_calloc
/#1 0x593752b28d0d in SEQUENCE_decode_uper
/#2 0x593752b9a546 in SET_OF_decode_uper
/#3 0x593752b2863c in SEQUENCE_decode_uper
/#4 0x593752b47363 in CHOICE_decode_uper
/#5 0x593752b2863c in SEQUENCE_decode_uper
/#6 0x593752b2863c in SEQUENCE_decode_uper
/#7 0x593752b2863c in SEQUENCE_decode_uper
/#8 0x593752b2863c in SEQUENCE_decode_uper
/#9 0x593752b2863c in SEQUENCE_decode_uper
/#10 0x593752b38551 in uper_decode
/#11 0x5937527d859f in nr_rrc_ue_process_masterCellGroup
/#12 0x5937527d9408 in nr_rrc_process_reconfiguration_v1530
/#13 0x5937527dd5bb in nr_rrc_ue_process_rrcReconfiguration
/#14 0x5937527f5e6b in nr_rrc_ue_decode_dcch
/#15 0x5937527ff003 in rrc_nrue
/#16 0x59375280c6de in rrc_nrue_task
N2 handover
This MR introduces full support for N2 handover, covering handover
decision, preparation, execution, and notification between source and
target NG-RAN nodes.
Key features:
1. Handover Decision & Preparation:
- Implement N2 handover decision based on UE measurement reports.
- Generate the Handover Preparation Information message, including
RRCReconfiguration.
- Send Handover Required message from the source NG-RAN to the AMF.
2. Handover Execution:
- Decode and handle the Handover Request on the target NG-RAN.
- Process the Handover Command on the source gNB, triggering
RRCReconfiguration.
- Initiate Handover Notify after successful completion.
3 NGAP & RRC Enhancements:
- Implement NGAP encoding/decoding functions for Handover Required,
Handover Request, Handover Command, Handover Failure, and Handover
Notify (3GPP TS 38.413).
- Adds NG-RAN Status Transfer support (UL/DL) for PDCP COUNT
preservation during mobility:
- support for NGAP Uplink and Downlink RAN Status Transfer messages
(TS 38.413 §9.2.3.13-14) to enable proper PDCP COUNT value
transfer during handover or recovery: NGAP encoding/decoding for
RAN Status Transfer, PDCP helpers to extract and apply COUNT (HFN
+ SN) per DRB. This aligns with TS 38.300 §9.2.3.2.1 and TS 23.502
§4.9.1.3.3, ensuring PDCP status preservation in AM.
4. Testing:
- Introduce a Telnet command to manually trigger N2 handover using UE
ID and neighbor PCI.
- Add configuration file for testing N2 handover with a target gNB.
* trigger upon reception of MasterKeyUpdate
* derive NH, store NH NCC and valid NH key in RRC
* masterKeyUpdate: derive enc/int keys after master key update
and set PDCP security for SRB1
* call nr_rrc_process_reconfiguration_v1530 before nr_rrc_ue_process_RadioBearerConfig
and move dedicatedNAS_MessageList processing at the end of the flow. The sequence
shall be (1) keys/security update (2) radioBearerConfig processing, with PDCP entity
creation, PDCP reestablishment, SDAP entity creation (3) NAS PDUs processing, which
triggers PDU Session Establishment Accept, which sets up the TUN interface.
SDAP entity is a pre-requisite, therefore the radioBearerConfig has to be processed
(in nr_rrc_ue_process_RadioBearerConfig, add_drb) early enough, or it may cause a
race condition in SDAP.
Jaroslava Fiedlerova