This commit adds support for the Handover Cancel initiating message
procedure code (NGAP_ProcedureCode_id_HandoverCancel).
Changes:
- ngap_gNB_decoder.c: Added case handler for Handover Cancel in
ngap_gNB_decode_initiating_message() to properly decode and log
incoming Handover Cancel messages from the AMF.
- ngap_gNB_encoder.c: Added Handover Cancel to the list of supported
initiating message procedure codes in ngap_gNB_encode_initiating(),
allowing the gNB to encode and send Handover Cancel messages.
The Handover Cancel procedure is already implemented in other parts of
the NGAP stack, these changes were missing to complete the support
by ensuring the procedure code is properly recognized in both the encoder
and decoder switch statements, following the same pattern as other
procedure codes.
In the current memory management the caller wasn't responsible for freeing
memory they allocate. The ngap_gNB_encode_pdu function was taking ownership
of PDU contents by calling ASN_STRUCT_FREE_CONTENTS_ONLY, while callers
also expected to manage the same memory. This created unclear ownership semantics and
potential double-free bugs.
- Remove ASN_STRUCT_FREE_CONTENTS_ONLY from ngap_gNB_encode_pdu to prevent double-free
- Remove unnecessary ASN_STRUCT_FREE when encode function returns NULL
- Add proper ASN_STRUCT_FREE cleanup for heap-allocated PDUs in ngap_gNB.c functions
- Add ASN_STRUCT_FREE_CONTENTS_ONLY cleanup for stack-allocated PDUs in NAS and context management functions
- Ensure consistent memory cleanup patterns across all NGAP encoder callers
- Fix potential memory leaks in all ngap_gNB_encode_pdu call sites
This prevents double-free bugs and ensures proper cleanup of ASN.1 structures
in both heap and stack allocation scenarios.
According to 4.9.1.3.3 of 3GPP TS 23.502:
> 2a. - 2c. The S-RAN sends the Uplink RAN Status Transfer message to the S-AMF,
> as specified in TS 36.300 [46] and TS 38.300 [9]. The S-RAN may omit sending
> this message if none of the radio bearers of the UE shall be treated with PDCP status preservation.
TS 38.300 says:
> For DRBs not configured with DAPS, the source gNB sends the SN STATUS TRANSFER message to the target
> gNB to convey the uplink PDCP SN receiver status and the downlink PDCP SN transmitter status of DRBs for
> which PDCP status preservation applies (i.e. for RLC AM). The uplink PDCP SN receiver status includes at
> least the PDCP SN of the first missing UL PDCP SDU and may include a bit map of the receive status of the out
> of sequence UL PDCP SDUs that the UE needs to retransmit in the target cell, if any. The downlink PDCP SN
> transmitter status indicates the next PDCP SN that the target gNB shall assign to new PDCP SDUs, not having a
> PDCP SN yet.
i.e., for DRBs for which PDCP status preservation applies (i.e. for RLC AM), which is is our case.
This commit introduces full support for NG-RAN Status Transfer message handling
(TS 38.413 §9.2.3.13-14) in CU. It enables correct state transfer of PDCP COUNT
values (SN + HFN) during mobility or recovery scenarios.
Summary of changes - NGAP:
* Added encoding/decoding support for UL/DL RAN Status Transfer message
* Defined structures for: ngap_drb_count_value_t, ngap_drb_status_t,
ngap_ran_status_container_t, ngap_ran_status_transfer_t
This commit introduces the NG Mobility Management Procedure known as
Handover Notification. The outbound message is sent by the target NG-RAN
and is known as Handover Notify. The procedure is used to indicate to
the AMF that the UE has arrived to the target cell and the NG-based
handover has been successfully completed
* after RRCReconfiguration complete, in the N2 callback for HO success
* add NGAP encoder for the message
* RRC callback to trigger Handover Notify message
Co-authored-by: batuhan duyuler <batuhan.duyuler@firecell.io>
This commit introduces the NG Mobility Management Procedure known as
Handover Resource Allocation. The inbound message is sent by the AMF
and is known as Handover Request.
Major changes:
(0) Add Handover Resource Allocation initiating message decoding
* add case for NGAP initiating message and unsuccessful message decoding
(1) handle Handover Request on the target NG-RAN
(2) decode NG Handover Request message
(3) process payload, e.g. create UE context,
store IDs, set UP security and trigger bearer setup
Co-authored-by: batuhan duyuler <batuhan.duyuler@firecell.io>
This commit introduces the NG Mobility Management Procedure known as
Handover Preparation. The outbound message is sent by the source NG-RAN
and is known as Handover Required.
* introduce NGAP library for Mobility Management
* introduce NGAP IEs encoder functions for Handover Required and relevant common IEs
* handle RRC trigger in NGAP and Send NGAP Handover Required to the AMF
Co-authored-by: batuhan duyuler <batuhan.duyuler@firecell.io>
Guido Casati