<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
[AMF] Implicit Network-initiated Deregistration
Two timers are introduced (both with duration of T3512 + 4 min):
-MOBILE_REACHABLE
-IMPLICIT_DEREGISTRATION
MOBILE_REACHABLE is set when NAS connection for the UE is released.
IMPLICIT_DEREGISTRATION is set when MOBILE_REACHABLE expires.
On MOBILE_REACHABLE expiry Paging is ignored.
On IMPLICIT_DEREGISTRATION expiry:
-UE's RM_State is set to DEREGISTERED
-UE is Nudm_SDM_Unsubscribed
-UE is Nudm_UECM_Deregistered
-PDU sessions are released
-AM policies are deleted
Existing flag amf_ue->network_initiated_de_reg is used.
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.
AMF does not crash anymore when a new UE registration request arrives,
and there is no available space left in UE context pool. Now it just
rejects the request with an error.
AMF subscribes to UDM for each registered UE.
At the moment, UDM does not send callback to AMF when any of the UE's
properties in the database changes.
At the moment, AMF does properly parse the ModificationNotification, but
does not do anything useful.
UDM may send a Deregistration Notification to AMF, to deregister
specific UE from the network - Network-Initiated Deregistration.
Deregistration procedure includes sending Deregistration Request to UE,
starting a timer T3522, releasing PDU sessions from SMF, releasing PCF
policies from PCF, and waiting for Deregistration Accept from UE.
Not yet implemented is:
- to prevent deregistration of UE in case it has any emergency sessions,
- page UE when UE is in IDLE mode.
TS24.501
8.2.11 DL NAS transport
8.2.11.4 5GMM cause
The AMF shall include this IE when the Payload container IE
contains an uplink payload which was not forwarded and
the Payload container type IE is not set to "Multiple payloads".
-0-
As such, this function 'nas_5gs_send_gsm_reject()' must be used
only when an N1 SM message has been forwarded to the SMF.
All process will be forcely exited if it failed to encode the S1AP/NGAP/GTP/PFCP message. It is to make sure there was no problem with the encoding of open5gs.
Most of the time, an application wants to perform some amount of data buffering
in addition to just responding to events. When we want to write data,
for example, the usual pattern runs something like:
1. Decide that we want to write some data to a connection;
put that data in a buffer.
2. Wait for the connection to become writable
3. Write as much of the data as we can
4. Remember how much we wrote, and if we still have more data to write,
wait for the connection to become writable again.
Now, Open5GS implements the above method by default when transmitting data
in a stream type socket.
In TS24.501 Ch 5.5.1.3.8 Abnormal cases on the network side
d) REGISTRATION REQUEST with 5GS registration type IE set to
"mobility registration updating" or "periodic registration updating"
received after the REGISTRATION ACCEPT message has been sent and
before the REGISTRATION COMPLETE message is received.
Since, we have to do this special case, it is desirable
to handle it directly inside the state(gmm-sm.c).