fix: issue 911 - OAI gNB hangs when AMF connection goes down
Once the AMF is down, based on the AMF UE NGAP ID and RAN UE NGAP ID,
the UE associated with the AMF is found
All the contexts related to the UE are released and the timer is started
in the NGAP to look up for the SCTP association. The AMF-gNB reconnection
is made if an SCTP connection is found, also the registration of multiple
UE is triggered
These actions are based on the reference from 4.2.6 AN release Specs
TS 123 502 V16.7.0 (2021-01)
When the NG-AP signalling connection is lost due to (R)AN or AMF failure,
the AN release is performed locally by the AMF or the (R)AN as described
in the procedure flow below without using or relying on any of the signalling
shown between (R)AN and AMF. The AN release causes all UP connections of the UE
to be deactivated.
closes#911
- Extended fix to support multiple UEs instead of single UE
- Actions now trigger upon AMF reconnection
Per 3GPP TS 123 502 V16.7.0 (2021-01) Section 4.2.6 (AN Release):
When NG-AP signalling connection is lost due to (R)AN or AMF failure,
AN release is performed locally by AMF or (R)AN without relying on
signalling between (R)AN and AMF. This deactivates all UP connections.
The code previously checked that the supplied PDU sessions's type is
exactly what we requested. However, at least OAI 5GC will only give us
an IPv4 PDU session if we request IPv4v6 (so the check would fail).
Extend the validation to either check exact match, or, if IPv4v6
requested, that it is either IPv4 or IPv6.
NR Paging on CU
Implements the NR paging path on the CU:
- NGAP Paging is decoded and passed to RRC
- RRC builds F1AP Paging, and distributes it to DUs via F1 callback
Changes:
- Refactor and extend F1AP Paging encode/decode libraries
* add missing enc/dec/eq/cp functions
* add unit test
* IEs: CN UE 5G-S-TMSI, RAN UE I-RNTI; optional DRX/priority/origin)
- Refactor CU callback CU_send_Paging
- Refactor DU handler DU_handle_Paging
- Refactor old F1 callback for Paging indication, extend it and align
with existing F1 callbacks in stack
- Refactor and extend NGAP Paging encode/decode lib
* add missing enc/dec/eq/cp functions
* add unit test
* Fixes NGAP paging to accept Paging only on SCTP stream 0 per TS
38.412
- Includes supporting refactors (PDU session split, shared 5G-S-TMSI
helpers, NGAP/F1AP cleanups)
Testing
- NGAP and F1AP Paging lib unit tests (enc/dec)
- Stream-0 fix validated with Open5GS AMF
This MR does not address the DU changes besides the F1 handler. F1AP
Paging does not have an RRC container to pass the PCCH message to the
DU, and F1 DL RRC Message Transfer does not apply to PCCH. PCCH-Message
shall be built at DU per TS 38.331 §5.3.2, with padding as per §8.5 and
delivered as RLC SDU per §8.2. For each cell in Paging Cell List that
belongs to this DU, queue for MAC. MAC schedules at PF/PO per TS 38.304
§7.
Refs:
- F1AP 3GPP TS 38.473 version 16.21.0 Release 16
- NGAP 3GPP TS 38.413 version 16.17.0 Release 16
Add a simple GTP unit test
Add a simple unit test for GTP that as of now tests the main
functionality, i.e., for a single UE, set up a bearer between two
endpoints and checking that traffic sending works. This is a start to
extend it further, e.g., with API changes, extensions to support new
functionality such as IPv6, and refactorings.
A number of supporting cleanup has been done as well.
For unit testing, allow to remove endpoints such that we could reuse a
port/IP combination.
The function does not take care of endpoints that are still "dangling",
it is the user's responsibility to remove all existing TEIDs.
Add a simple unit test that tests sending unidirectional traffic. So
far, it merely replicates what is already in nr-cuup-load-test, but it's
a single executable (so easier to handle), and could be more easily
extended to further tests (e.g., IPv6).
A couple of ideas for refactoring/improvements have been added in
comments in the test.
Paging messages are classified as non-UE-associated signalling per
3GPP TS 38.412 clause 7 (TL), which requires them to be sent on
stream 0 (or a reserved stream pair).
Paging message is received when UE is in RRC_IDLE or RRC_INACTIVE
state, as the RAN has no active UE context and paging targets the
UE by 5G-S-TMSI rather than RAN-UE-NGAP-ID.
The previous implementation incorrectly rejected paging messages
received on stream 0, causing paging failures when using Open5GS AMF.
Changes:
- Accept paging on stream 0 (non-UE-associated signalling)
- Reject paging on non-zero streams (UE-associated streams)
- Add documentation
Add F1AP Paging library and new message type to follow the existing F1AP
library pattern and to support multi-cell paging and both RAN UE (I-RNTI)
and CN UE (5G-S-TMSI) paging identities at the library level per TS 38.473.
* New library (f1ap_paging.c/h, f1ap_lib_includes.h, CMakeLists.txt)
- Implement encode/decode/copy/eq/free for F1AP Paging (procedure 9.2.6).
- Add ASN.1 includes for Paging, PagingIdentity, CN/RAN UE identities.
- Enables unit testing of Paging enc/dec in f1ap_lib_test.c.
* New types in f1ap_messages_types.h (existing f1ap_paging_ind_t unchanged)
- f1ap_paging_t: UE Identity Index, paging identity (union + type enum),
optional paging_drx, paging_priority, paging_origin, and paging_cells[].
- f1ap_paging_cell_item_t, f1ap_paging_identity_type_t, f1ap_paging_identity_t
for multi-cell list and RAN/CN identity discrimination.
- Paging Origin IE is optional per F1AP 8.7.1.2.
Tests: test_f1ap_paging() roundtrip and copy for CN UE (5G-S-TMSI) and
RAN UE (I-RNTI) cases, with optional IEs.
- Refactor ngap_paging_ind_t (openair2/COMMON/ngap_messages_types.h):
- optional paging_drx and paging_priority as pointers
- TAI list as tai_list[] and n_tai
- add optional IEs: Paging Origin, Paging Attempt Information,
UE Radio Capability for Paging.
- Introduce nr_tai_t, ngap_paging_attempt_info_t, ngap_paging_origin_t;
- generate paging enums via FOREACH macros.
- Add NGAP Paging encode/decode/eq/free in openair3/NGAP/ngap_gNB_paging.c
(encode_ng_paging, decode_ng_paging, eq_ng_paging, free_ng_paging).
- Replace inline Paging decode in ngap_gNB_handle_paging() with
decode_ng_paging() and add error handling; add eq_ngap_plmn() in
ngap_common.
- Update rrc_gNB_NGAP.c to use tai_list/n_tai and optional paging_drx
when forwarding paging to F1AP.
- Add ASN.1 includes for Paging in ngap_msg_includes.h; register
ngap_gNB_paging.c in root CMakeLists.txt.
- Add NGAP unit test (openair3/NGAP/tests/ngap_lib_test.c): encode/decode
roundtrip for Paging; tests subdirectory and executable under
ENABLE_TESTS in openair3/NGAP/CMakeLists.txt.
ngap_common.h is for common IEs enc/dec functions, utilities
should go into a separate file. Changes in this commit:
* Add ngap_utils.h (utilities)
* Move helper macros (NGAP_ERROR, NGAP_DEBUG, NGAP_FIND_PROTOCOLIE_BY_ID, etc.) to ngap_utils.h
* Move equality check macros (_NGAP_EQ_CHECK_*) to ngap_utils.h
* Clean up includes
This change is preparatory to the introduction the paging lib with unit
tests, with the goal of reducing the inter-dependency between concurrent
NGAP libs.
TO_ENUM/TO_TEXT are already used in NAS, and can be adopted in NGAP.
To avoid duplication, the following changes are introduced:
* Move text_info_t, TO_ENUM, TO_TEXT to common/utils/utils.h
* Include utils.h include to ngap_messages_types.h, fgs_nas_utils.h, and fgmm_lib.h
* RRC establishment cause: refactor to FOREACH_RRC_ESTABLISHMENT_CAUSE macro
* Cause Group: refactor to FOREACH_CAUSE_GROUP macro
* Radio Network Cause: refactor to FOREACH_CAUSE_RADIO_NETWORK macro
* Protocol Cause: refactor to FOREACH_CAUSE_PROTOCOL macro
This change is preparatory to the introduction the paging lib with unit
tests, with the goal of reducing the inter-dependency between concurrent
NGAP libs.
These conversion functions will be needed across different
NGAP libraries upon refactoring: tnl_to_bitstring, bitstring_to_tnl
Therefore, they are moved to the common lib.
PDU session related NGAP messages do not belong to NAS procedures lib.
* Create ngap_gNB_pdu_session_management.c and .h
* Move out ngap_gNB_pdusession_setup_resp, ngap_gNB_pdusession_modify_resp,
ngap_gNB_pdusession_release_resp from ngap_gNB_nas_procedures.c
* Move encode_ngap_pdusession_setup_response_transfer to ngap_common.c:
this transfer IE is common used both in PDU Session Management and
Initial Context Setup, so it's moved to the common lib
* Add ngap_gNB_pdu_session_management.c to CMakeLists.txt
This commit centralizes equality-check behavior and removes duplicated
macro implementations across protocol stacks.
Major changes:
- add `common/utils/eq_check.h` with shared `_EQ_CHECK_*`,
`EQ_CHECK_GENERIC`, and optional-IE pointer helpers
- replace E1AP/F1AP/NAS local equality macros and call sites with
the shared helpers
- remove duplicated layer-specific error/equality macro definitions from
common headers and switch includes to `eq_check.h`
- update CMake test flags to define `ENABLE_TESTS` for `e1ap_lib`,
and 5GS NAS libraries; drop `E1AP_LOG_ERRORS` - equality-check/error
printing is now consistently controlled by `ENABLE_TESTS`
RRC: Multi-cell handling architecture
This MR implements a foundational multi-cell handling architecture for
RRC by separating DU management from cell management and establishing a
hierarchical cell organization within each DU container. The changes
enable proper multi-cell support where each DU can serve multiple cells,
addressing the previous limitation where DU and cell management were
tightly coupled with the assumption of one cell per DU.
Key Changes:
- Data Structure Separation: Separated for DU containers (DU-specific
info) from cell containers (cell-specific data)
- Global DU and Cell Trees: Cells are now stored in global RB trees in
RRC, similarly to DUs
- Du-specific cell seq_arr: within each DU container (du->cells) is
stored a seq_arr of cells belonging to the DU
- UE Cell Association Framework: Introduced serving_cells array to track
PCell and SCells for each UE with servCellIndex indexing
- Cell Management Library: Extracted cell management functions into
rrc_cell_management.c/h for better testability and maintainability
Other relevant changes:
- F1AP Refactoring: cell list definitions, heap allocation to prevent
stack overflow
- 5G-S-TMSI Helpers: Common helper functions for 3GPP TS 23.003
compliant construction
- Integration Tests: Comprehensive test suite for DU lookup, cell
lookup, and UE cell association
- Cell Duplication Checks: Validation in F1 DU configuration update to
prevent duplicate cells
- Documentation: Updated RRC developer documentation with multi-cell
architecture details
Validated with RFsim in re-establishment and handover scenarios.
Move the module cmake code to its subdirectory for better organization,
and remove superfluous include_directories() that are not recommended
to be used (as it populates all other targets with those directories,
most of which don't need it anyway).
Slightly clean up the module by removing headers to unused dependencies.
The GTP module has a dependency to 4G and 5G RLC, which should not exist
(the RLC modules have a dependency on GTP, not the other way around),
but in this commit, make as little modifications as possible.
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
* 5G-S-TMSI construction is defined in 3GPP TS 23.003 and
relevant at both gNB and UE side
* Add helper functions to be later used in NG Paging
* Adopt in NAS UE
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
Add Ethernet PDU session support and make PDU session request configurable
This MR adds support for Ethernet PDU sessions, and makes PDU sessions
configurable: per-PDU session ID, type (IPv4/IPv4v6/IPv6/Ethernet [1]),
DNN, NSSAI.
Concretely, it adds a new configuration file section pdu_sessions below
uicc0 that looks like this if everything is specified (default values
are shown):
uicc0:
[...]
pdu_sessions:
- id: 1
type: "IPv4"
nssai_sst: 1
nssai_sd: 0xffffff
dnn: "oai"
It is possible to list multiple PDU sessions (add new line - id: 2 to
request a second PDU session). It is backwards-compatible to the current
PDU session configuration (uicc0.dnn/nssai_sst/etc), the idea being that
either legacy or new configuration could be used, but (1) if
pdu_sessions exist, it will overwrite the legacy configuration, and (2)
multiple PDU sessions, and type, can only be configured using the new
config. The old parameters --extra-pdu-id and --default-pdu-id are not
accepted anymore. Documentation has been added to the UE tutorial.
It is possible to test an Ethernet PDU session [1]. It is possible to
test the PDU session inside the UE by verifying it has an TAP interface
oaitap_ue1, and ARPing the data network (arping has been added to
oai-nr-ue container for that purpose):
ip addr add 192.168.72.140/26 dev oaitap_ue1 # same subnet as data network!
ip link set dev oaitap_ue1 up
arping -c 20 -I oaitap_ue1 192.168.72.135 # will send ARP request in Ethernet frame to get IP address of data network
[1] See description MR !3769 for more information. On the UE side, only
the type has to be changed to "Ethernet".
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
Look up the index of a PDU session in the list of PDU sessions upon
accept to determine if the PDU session is the default (first PDU
session) or not. If it is the default, it will not append a suffix to
the interface name (oaitun_ueY), otherwise append the PDU session ID
(e.g., for 5: oaitun_ueYp5).
Use the new PDU session configuration functionality of the parent
commit. It is now possible to request multiple PDU sessions, and to
request specific PDU session types. While the new uicc0.pdu_sessions is
preferred, it is still possible to use the "legacy"
uicc0.dnn/nssai_sst/nssai_sd.
The old parameters --default-pdu-id and --extra-pdu-id are not allowed
anymore, as it is possible to manually define this in the UE
configuration. Correspondingly, fix the use of those options, where
applicable.
Note: since the default_pdu_id is changed to -1, all interface names
will have pX to interface names appended (oaitun_ue1pX). The next commit
will correct this.
Jaroslava Fiedlerova