A friend in the community was trying to connect an SMF made by another
manufacturer with an SBI interface and found a big problem with Open5GS.
All of the code in the part that generates the Resource URI
from HTTP.location is invalid.
For example, suppose we create a Resource URI with SMContext as below.
{apiRoot}/nsmf-pdusession/<apiVersion>/sm-contexts/{smContextRef}
In this case, Open5GS extracted the {smContextRef} part of the HTTP.location
and appended it to the beginning
{apiRoot}/nsmf-pdusession/<apiVersion>/sm-contexts/.
This implementation may not work properly if the apiRoot changes.
Consider a different port number as shown below.
<HTTP.location>
127.0.0.4:9999/nsmf-pdusession/v1/sm-contexts/1
The SMF may send an apiRoot to the AMF with a changed port number,
in which case the AMF must honor it.
Therefore, instead of extracting only the smContextRef from HTTP.location,
we modified it to use the whole thing to create a Resource URI.
We modified all NFs that use HTTP.location in the same way, not just SMFs.
Cause is set according to particular NF standard.
Additionally:
- OGS_SBI_HTTP_STATUS_MEHTOD_NOT_ALLOWED typo fixed.
- [PCF] Fixed SM Policy establishment error handling
* [AUSF] Fix removing UE context on authentication removal request
AUSF crashed when trying to access ausf_ue->sm fields after they were
already deleted.
* [AMF] Delete UE authentication result after UE deregisters from 5G core
Based on TS 29.509 - 5.2.2.2.5 Authentication Result Removal with 5G AKA
method:
In the case that the Purge of subscriber data in AMF after the UE
deregisters from the network or the NAS SMC fails following the
successful authentication in the registration procedure, the NF Service
Consumer (AMF) requests the AUSF to inform the UDM to remove the
authentication result.
<nf>/init.c:<nf>_main() :
ogs_pollset_poll() receives the time of the expiration of next timer as
an argument. If this timeout is in very near future (1 millisecond),
and if there are multiple events that need to be processed by
ogs_pollset_poll(), these could take more than 1 millisecond for
processing, resulting in the timer already passed the expiration.
In case that another NF is under heavy load and responds to an SBI
request with some delay of a few seconds, it can happen that
ogs_pollset_poll() adds SBI responses to the event list for further
processing, then ogs_timer_mgr_expire() is called which will add an
additional event for timer expiration. When all events are processed
one-by-one, the SBI xact would get deleted twice in a row, resulting in
a crash.
0 __GI_abort () at ./stdlib/abort.c:107
1 0x00007f9de91693b1 in ?? () from /lib/x86_64-linux-gnu/libtalloc.so.2
2 0x00007f9de9a21745 in ogs_talloc_free (ptr=0x7f9d906c2c70, location=0x7f9de960bf41 "../lib/sbi/message.c:2423") at ../lib/core/ogs-memory.c:107
3 0x00007f9de95dbf31 in ogs_sbi_discovery_option_free (discovery_option=0x7f9d9090e670) at ../lib/sbi/message.c:2423
4 0x00007f9de95f7c47 in ogs_sbi_xact_remove (xact=0x7f9db630b630) at ../lib/sbi/context.c:1702
5 0x000055a482784846 in amf_state_operational (s=0x7f9d9488bbb0, e=0x7f9d90aecf20) at ../src/amf/amf-sm.c:604
6 0x00007f9de9a33cf0 in ogs_fsm_dispatch (fsm=0x7f9d9488bbb0, event=0x7f9d90aecf20) at ../lib/core/ogs-fsm.c:127
7 0x000055a48275b32e in amf_main (data=0x0) at ../src/amf/init.c:149
8 0x00007f9de9a249eb in thread_worker (arg=0x55a483d41d90) at ../lib/core/ogs-thread.c:67
9 0x00007f9de8fd2b43 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:442
10 0x00007f9de9063bb4 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:100
Other NF instances are obtained through NRF
or created directly through configuration files.
Other NFs created by the config file should not be passed
through NRF discovery or anything like that.
Since self-created NF Instances do not have an ID,
they are implemented to exclude them from NRF Discovery.
The current load percentage of the NF Service Consumer is provided
in the payload body of the PATCH request when periodically
contacting the NRF (heart-beat).
AMF: ratio between currently connected ran_ue and maximum number of them
SMF: ratio between current PDU sessions and maximum available
PCF: ratio between current AM+SM policy associations and maximum available
or ratio between currently connected UEs and maximum number of them
(the load which is higher)
AUSF, UDM: ratio between currently connected UE and maximum number of them
BSF: ratio between current sessions and maximum available
NSSF: ratio between currently used NSIs and maximum number of them
NRF currently doesn't determine that the NF Profile has changed.
== Known limitation ==
Placing npcf-smpolicycontrol and pcf-policyauthorization
in different NFs is not supported. Both npcf-smpolicycontrol
and pcf-policyauthorization should be placed in the same NF.
1. UE registered and PDU established.
2. PCF does not receive Heartbeat.
- PCF De-registered state.
- Since PDU is established, SMF should not remove NF instance
3. PCF re-registered.
- HERE, WE NEED TO INCREASE NF REFERENCE COUNT.
Otherwise, NF instance will be removed if PCF is de-registered state
4. UE sends PDU release request.
5. Because SMF knows PCF NF instance, SMF can send PCF delete
Sukchan Lee
gstaa
Šimon Lukašík
Bostjan Meglic
Bostjan Meglic
Gaber Stare
mitmitmitm
Bostjan Meglic