This commit refactors the PDU Session Resource Modify Response message
structures to improve naming, documentation, and compliance with 3GPP TS 38.413 9.2.1.6.
Changes in NGAP:
- Rename qos_flow_tobe_modified_t to qos_flow_addmod_response_item_t to better
reflect its purpose as a QoS Flow Add or Modify Response Item IE (as per specs)
- Add mandatory AMF UE NGAP ID field to ngap_pdusession_modify_resp_t structure
- Optimize field types: change nb_of_pdusessions and nb_of_pdusessions_failed
from uint16_t to uint8_t (NGAP_MAX_PDU_SESSION limit) (ref 3GPP TS 38.413, 9.2.1.6)
- Update PDU Session Modify Response encoder to use amf_ue_ngap_id from the
message structure (pdusession_modify_resp_p->amf_ue_ngap_id) instead of
retrieving it from UE context (ue_context_p->amf_ue_ngap_id)
- Add comprehensive comments with 3GPP TS 38.413 section references throughout
Changes in RRC/NGAP:
- Populate amf_ue_ngap_id field in PDU Session Modify Response message from
UE context
- Update type reference to qos_flow_addmod_response_item_t
semi-manual remove of not used #define commands
As i was upset to see all these #define with no code under, i made a
global pass to remove the obvious cases semi-manual remove of not used
bodies
manual script, then a lot of manual review
grep -IRs "#define" ../openair* ../common/* ../executables/ ../nfapi/ ../radio/ | \
fgrep -v '(' | fgrep -v '//' |awk '{print $2}' | egrep -v "#define *$n"| \
while read n ; do
grep -IRs $n ../openair* ../common/* ../executables/ ../nfapi/ ../radio/ | grep -v "#define *$n" | grep -q $n || echo $n;
done
will give a decent list of #define never used. Then, I think we should
keep lists of # define when it comes from standards, even if the code
doesn't use it right now
NGAP: improve error handling in RRCReconfiguration from Handover Command decoding
This MR refactors doRRCReconfiguration_from_HandoverCommand for consistency and
safety, and enables NGAP Handover Cancel encoding/decoding.
- Refactored doRRCReconfiguration_from_HandoverCommand function:
- Changed signature to return byte_array_t instead of taking a buffer parameter
- Prevents buffer overflow by auto-sizing memory with uper_encode_to_new_buffer
- Input validation
- HandoverCommand structure validation
- Error handling and cleanup for encode/decode failures
- ASN.1 structure cleanup on all error paths
- Updated caller in rrc_gNB_NGAP.c: use new byte_array_t return signature,
added buffer cleanup with free_byte_array(), sends Handover Cancel to AMF on
decoding failure (source gNB)
- Improved error logging
- NGAP Handover Cancel encoding/decoding support
- Added missing Handover Cancel ack case handler for
NGAP_ProcedureCode_id_HandoverCancel in ngap_gNB_decode_initiating_message()
to decode and log incoming Handover Cancel Ack message
- Added NGAP_ProcedureCode_id_HandoverCancel to the list of supported
initiating message procedure codes in ngap_gNB_encode_initiating() allowing
the gNB to encode and send Handover Cancel messages
Note: The Handover Cancel procedure is already implemented elsewhere in the NGAP
stack; these changes complete support by ensuring the procedure code is
recognized in both encoder and decoder.
Closes#1043
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.
On NGSetupFailure, before moving, we might have
[NGAP] Received NG setup failure for AMF... please check your parameters
[NGAP] Received NGSetupResponse from AMF
In the Initial Context Setup message, the NGAP forwards the AMF UE ID,
but not in the DL NAS Message, although 38.413 says, in $8.3.1.2 either
> The NG-RAN node shall use the AMF UE NGAP ID IE and RAN UE NGAP ID IE
> received in the INITIAL CONTEXT SETUP REQUEST message as identification
> of the logical connection
or in $8.6.2.2
> The NG-RAN node shall use the AMF UE NGAP ID IE and RAN UE NGAP ID IE
> received in the DOWNLINK NAS TRANSPORT message as identification of the
> logical connection
So forward in both cases for harmonization.
The PDUSessionResourceReleaseResponse message was missing the mandatory
pDUSessionResourceReleaseResponseTransfer IE in each released PDU session item. This caused Open5GS to send an error indication.
Changes:
- Add encode_ngap_pdusession_release_response_transfer() function to
properly encode the transfer structure (empty since Secondary RAT Usage
Information is optional and not used, per 9.3.4.21)
- Always include the mandatory PDUSessionResourceReleasedListRelRes IE
- Always encode the pDUSessionResourceReleaseResponseTransfer for each
PDU session item
- Fix Release Command handler to decode and log Cause from command transfer:
instead of incorrectly copying command data to response: the 2 transfer
IEs in the Command and the Response messages are different and should
not be mixed
- Split Command/Response struct type definitions
- Add missing includes
1) Remove UE Context Release Response code: there is no
such thing in the specs, it is either UE Context Release Request
(NG-RAN node initiated) or UE Context Release (AMF initiated)
(3GPP TS 38.413). The former message has only the request, no
response is defined by the specs. The code in the stack had no
purpose at all and was removed.
2) The UE Context Release Request message only contains a PDU
Session Resource List (optional) of PDU Session IDs, therefore
the use of pdusession_release_t was wrong and was refactored
- Corrected AMF Set ID data type in ngap_gNB_nnsf_select_amf_by_amf_setid() from uint8_t to uint16_t.
- AMF Set ID is a 10-bit field as per 3GPP TS 38.413 §9.3.3.12.
- The incorrect data type caused truncation for AMF Set IDs >255, leading to lookup failures during RRC reestablishment.
- Verified successful reestablishment with large AMF Set IDs after the fix.
Reason for fix: AMF lookup using AMF Set ID was failing because the 10-bit AMF Set ID was truncated to 8 bits.
Closes#1012
This commit is removing the storage of selected PLMN in NGAP UE context.
We store the Serving PLMN in the RRC UE context instead.
The Selected PLMN is the PLMN that the UE chose (or was directed to) for registration
and it is sent in the RRCSetupComplete. This is different from the selected
PLMN mentioned in the NG INITIAL UE MESSAGE for network sharing.
Selected PLMN: determines which core network and AMF the UE is registered with
GUAMI = Identifies the serving AMF and includes the PLMN of that AMF
Serving PLMN: the PLMN that is currently serving the UE (e.g. contained in GUAMI)
The AMF’s PLMN may match the selected PLMN, or not (especially in network sharing or roaming).
Regardless, the UE always have a Serving PLMN.
Initial UE message does not have a TAI IE per se, but TAI is a mandatory
member of the mandatory UserLocationInformation CHOICE.
NR CGI is also mandatory and carried inside UserLocationInformation:
in network sharing, the PLMN ID in TAI takes on additional
significance: RAN is shared but CN are different, so in this case PLMN in TAI is
needed for the AMF route the message to the correct operator’s core.
If network sharing applies (e.g., shared RAN between PLMN-A and PLMN-B):
the UE or network may select PLMN-B instead, and that PLMN identity
is included in the Initial UE Message’s TAI IE.
Conclusion:
1) UE always sends the selected PLMN during the registration,
regardless of whether it is shared or not.
2) Selected PLMN Identity is an actual IE sent in the RRCSetupComplete
while in NGAP there's no Selected PLMN Identity IE, only PLMN Identity
IEs in both TAI and NR CGI. It is a subtle difference.
3) The serving PLMN of the UE needs to be stored in RRC UE Context for
later use in NAS procedures. e.g. at initial registration it matches
the Selected PLMN
4) No need to store PLMN in NGAP UE Context, params are passed by RRC
5) TAI and NR CGI, which contain the PLMN identity, are mandatory in
UserLocationInformation IE CHOICE, and should reflect current status
Changes
- Initial UE Message: pass UE-selected PLMN and NR cell id from RRC to NGAP
- Uplink NAS Transport: use PLMN, TAC, and cell id provided by the message;
- Build NR CGI from gNB ID + cell id
- Store UE-selected PLMN only in RRC UE context at NAS_FIRST_REQ for later
Uplink NAS, stop storing PLMN in NGAP UE context
- ngap_gNB_handover_notify: Fix misleading error message from 'Failed to encode'
to 'Failed to find UE context' for better clarity
- ngap_gNB_handle_ul_ran_status_transfer: Standardize error message format
from 'Could not find' to 'Failed to find' for consistency across functions
This ensures consistent and accurate error reporting across all NGAP handover functions.
- Update encoder functions in ngap_gNB_mobility_management.c to use calloc_or_fail
- Provides zero-initialized memory and consistent error handling
- Prevents uninitialized fields and improves memory safety
Also:
- Update NG Setup Request to use calloc_or_fail
Move UE context creation and storage to after successful PDU encoding
to prevent memory leaks if encoding fails. Also add proper PDU cleanup
when AMF fetch fails and use consistent NULL check style.
This ensures UE context is only stored when the operation is guaranteed
to succeed, improving error handling and memory management.
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.
- Replace error handling for impossible ID mismatches with DevAssert statements
- If ngap_get_ue_context() succeeds, returned context must have matching NGAP gNB UE IDs by definition
- This catches potential bugs in the lookup function immediately
- Affects: handover_required, handover_notify, handover_cancel, ul_ran_status_transfer
These checks were logically impossible since we looked up the context using
the same IDs we were then checking for mismatch.
* There is no IE corresponding to PDU sessions failed to release
in the PDU SESSION RESOURCE RELEASE RESPONSE message. This was removed
and the corresponding code was refactored and cleaned up.
* In the Release Command handler, only established PDU Session are set to be
released. The Response message is filled accordingly.
- Move QoS-related enums and structures from ngap_messages_types.h to 5g_platform_types.h
- Replace ngap_* QoS types with generic qos_* types for better reusability
- Update field names from allocation_retention_priority to arp for consistency
- Update all references across RRC and NGAP modules to use new type names
- Remove duplicate QoS type definitions from NGAP-specific header
This improves code organization by centralizing QoS parameter definitions
in a common platform types header and eliminates NGAP-specific naming
in favor of more generic, reusable type definitions.
Previously, the RRC layer was incorrectly allocating stack memory for the ho_required_transfer field and passing it to NGAP, however it was not used. The IE is mandatory but contains only 1 optional IE, therefore is encoded in the NG message with empty content.
Changes:
- Remove unnecessary ho_required_transfer field from pdusession_resource_t definition, the IE is encoded anyway with empty content. If Direct Forwarding Path Availability is needed at any stage in the future it can be added to pdusession_resource_t and filled in RRC.
- Add clarifying comment about empty HandoverRequiredTransfer structure
This commit completes the NGAP Mobility Management procedure for N2 handover.
Upon failure on source gNB the Handover Cancel message is sent to the AMF which
in return responds with an ack.
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>
* 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 completes the NG Mobility Management Procedure known as
Handover Resource Allocation. The outbound message is sent by the
target NG-RAN and is known as Handover Request Acknowledge.
Major changes:
* add RRC callback to trigger the generation of NG Handover
Request Acknowledge on the target NG-RAN
* add NG Handover Request Acknowledge encoder
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 message is sent from the Target NG-RAN to the AMF.
The commit introduces:
* NGAP encoding function
* N2 callback for the target gNB
* handle the failure in RRC, inform NGAP
* send NGAP message to AMF via SCTP
Note: UE context in NGAP is fetched from the amf_ue_ngap_id
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>
This was a problem with open5gs and more than one PDU session.
The core network sets UE AMBR only once, leading to failure in the gNB
for the second PDU session.
(A proper handling of AMBR has to be develop at some point in the gNB.)
Motivation of the commit:
Previously, the RRC module on the NGAP interface directly handled ASN.1 decoding
of NGAP PDU Session Resource items, that was directly stored in pdusession_t, i.e.
in the UE context. Decode logic between Setup and Modify was also duplicated.,
e.g. fill_qos/fill_qos2. The idea behind this change is to achieve this flow:
(1) NGAP handler: decoding (2) ITTI to RRC: transfer decoded message (3) RRC
handler: process decoded message, e.g. store in UE context, etc..
The goal of this commit is to:
* improve the NGAP decoding library by adding decoding functions
* let RRC handle the already decoded data
* enhance error handling, with decode failures now consistently detected and rejected early
* have a cleaner, more maintainable code with fewer duplications and a clearer separation of modules
Changes:
* Moved all ASN.1 decode logic for PDU Session Resource items into the NGAP library
* Introduced decode functions for NGAP IEs whenever necessary, e.g. decode_TNLInformation
decode_pdusession_transfer
* Removed duplicate fill_qos functions and centralized QoS handling in NGAP
* Added function to copy from NGAP PDU Session Resource item to RRC pdusession_t: this actually
replaces decodePDUSessionResourceSetup in RRC, copying from the decoded NGAP struct to
the UE context pdusession_t
Rename the struct members:
`pdusession_param` to `pdusession` in NGAP Initial Context Setup Request
`pdusession_setup_params` in `ngap_pdusession_setup_req_t`
`pdusession_modify_params` and `ngap_pdusession_modify_req_t`
* Remove drb_is_active: function is unused and the logic will be later
added to another function to add DRBs if necessary
* Remove unused NGAP structs and empty TODO functions
* Remove unused pdusession_setup_req_t struct definition
Fix AMF selection fallback by PLMN ID when no UE identity is present or matching
If a mask is present (i.e., not zero), AMF selection by PLMN ID may
still fail, causing the AMF selection process to skip the fallback
option, i.e. selection by PLMN ID, when no UE identity is available or
when no match is found.
This MR adds also warnings in case there's a match for the AMF is not
found.
The mask could be present, .e.g not zero, but the selection of the AMF could
fail. This would lead to a skipping the selection of the AMF by PLMN ID,
which is the last option when no UE identity is present and/or matching.
Free memory allocated in NGAP after use in RRC.
Direct leak of 29 byte(s) in 1 object(s) allocated from:
> #0 0x7f11200b4887 in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:145
> #1 0x558b7fcd0137 in malloc_or_fail /n2-handover-preparation/common/utils/utils.h:86
> #2 0x558b7fcd0137 in create_byte_array /n2-handover-preparation/common/utils/ds/byte_array.c:32
> #3 0x558b7fdb7a5c in rrc_gNB_send_NGAP_NAS_FIRST_REQ /n2-handover-preparation/openair2/RRC/NR/rrc_gNB_NGAP.c:183
> #4 0x558b7fd2ab30 in rrc_gNB_process_RRCSetupComplete /n2-handover-preparation/openair2/RRC/NR/rrc_gNB.c:439
> #5 0x558b7fd2ab30 in handle_rrcSetupComplete /n2-handover-preparation/openair2/RRC/NR/rrc_gNB.c:1715
> #6 0x558b7fd63e23 in rrc_gNB_decode_dcch /n2-handover-preparation/openair2/RRC/NR/rrc_gNB.c:1851
> #7 0x558b7fd8b4c3 in rrc_gnb_task /n2-handover-preparation/openair2/RRC/NR/rrc_gNB.c:2718
> #8 0x7f111ea94ac2 in start_thread nptl/pthread_create.c:442
this commit is refactoring the function ngap_gNB_handle_nas_first_req
to (1) fill first a local instance of ngap_gNB_ue_context_t and then
(2) pass it to ngap_store_ue_context which will allocate memory
for the instance to store in ngap
This function is needed also in upcoming NGAP
libraries (i.e. N2 Handover) and therefore is moved
to the NGAP utilities file. The function converts
transport_layer_addr_t data struct to BIT_STRING_t
by copying the content of its members. The naming
is also updated to tnl_to_bitstring.
* Functions added:
decode_ngap_guami
decode_ngap_UEAggregateMaximumBitRate
decode_ngap_nssai
decode_ngap_security_capabilities
decode_ngap_mobility_restriction
* Adopt these functions in the common NGAP library
Guido Casati