'node_timeout' and some other functions can remove a smf_sess_t
while that session is still waiting for a PFCP reply
and has an active PFCP xact.
In this case, xact->data points to the deleted session
and xact's timeout function (sess_5gc_timeout for example)
eventually refers to this already freed session.
This fix prevents duplicate deletes from occurring by checking to see
if the session context has already been deleted when the timeout occurs.
Additionally, it moves session deletions out of timer callbacks into
state machine by reselect_upf().
Due to the way 'ogs_timer_mgr_expire' calls timer callbacks,
one must not stop or expire timers from within a timer callback.
And now one must not remove sessions from within a timer callback.
If eg. PCRF or AAA diameter link is not yet ready (eg. PCRF crashed), and
a client sends a CreateSessionRequest announcing its ow F-TEID,
then open5gs-smfd answers with Create Session Response Cause=
"Remote peer not responding", but it is not setting the received F-TEID
in the header of the response, instead it sends with TEI=0.
As a result, the peer cannot match the CreateSessionResponse, and needs
to rely on its own timeout timer to figure out that specific request failed.
This also happens in PFCP, so to solve this problem, I added teid/seid_presence
to the interface that sends the error message as shown below.
void ogs_gtp2_send_error_message(ogs_gtp_xact_t *xact,
int teid_presence, uint32_t teid, uint8_t type, uint8_t cause_value);
void ogs_pfcp_send_error_message(
ogs_pfcp_xact_t *xact, int seid_presence, uint64_t seid, uint8_t type,
uint8_t cause_value, uint16_t offending_ie_value);
TS23.007 17.4.1
19A PFCP based restart procedures
After a PFCP entity has restarted, it shall immediately update all local Recovery Time Stamps and shall clear all remote
Recovery Time Stamps. When peer PFCP entities information is available, i.e. when the PFCP Association is still alive,
the restarted PFCP entity shall send its updated Recovery Time Stamps in a Heartbeat Request message to the peer
PFCP entities before initiating any PFCP session signalling.
* [pfcp] response_timeout should never call ogs_pfcp_xact_delete (#50)
* also remove ogs_pfcp_xact_delete since never called
* also had to catch one more ogs_pfcp_sendto()
---------
Co-authored-by: Spencer Sevilla <spencer@MacBook-Air.local>
- Set the number of UEs in units of AMF/MME instead of gNB/eNB.
- See default value as shown below
Number of UEs per AMF/MME : 4,096
Number of gNB/eNB per AMF/MME : 32
Sukchan Lee
Pau Espin
Spencer Sevilla
Bostjan Meglic