* [SMF] rename function s/gtp/gtp2/
* [SMF] Store GTPC version in session
So far we always depended on an xact being present in the code path in
order to know which kind of session it is (GTPv1C vs GTPv2C). Let's
instead store that information in smf_sess_t so that we have it always
available in an easy way.
* [SMF] Move smf_sess_t GTPv1C specifics into gtp substruct
* [SMF] Gy CCR: append 3GPP-NSAPI AVP
* [SMF] Append PDP-Address AVP to Gy CCR msg
* [SMF] Gy CCR: Move some AVPs under Service-Information/PS-Information
They belong there. Nokia infocenter documentation seems to be document
the possibility to configure its software to have it in top level, but
that's not what 3GPP TS 32.299 states, so let's stick to it.
* [SMF] Gy CCR: append 3GPP-PDP-Type AVP
* [SMF] Gy CCR: append 3GPP-Charging-Id AVP
* [SMF] Gy CCR: append SGSN-Address AVP
* [SMF] Gy CCR: append GGSN-Address AVP
Issue:
When the ULA - Subscription Data does not contain MSISDN, the Create Session Request
from MME to SGW does not contain MSISDN IE resulting in SMF throwing following log
smf | 05/09 15:20:53.683: [smf] ERROR: No MSISDN (../src/smf/s5c-handler.c:82)
sgwc | 05/09 15:20:53.683: [sgwc] ERROR: No Context in TEID (../src/sgwc/s5c-handler.c:104)
mme | 05/09 15:20:53.683: [mme] ERROR: No Context in TEID (../src/mme/mme-s11-handler.c:122)
As per 3GPP TS 29.274 version 16.5.0, table 7.2.1-1: MSISDN IE shall only be included
in Create Session Request if its provided in subscription data from the HSS. This commit
fixes this by removing the mandatory MSISDN IE check in SMF.
In the past only GTPv2C was supported, and had the "gtp" generic prefix.
Later on, GTPv1C support was added, and "gtp1" prefix was used.
Let's move GTPv2C specific bits to have "gtp2" prefix too, and leave
"gtp" prefix for generic stuff among different GTP versions.
The use of the Gy interface (SMF acting as CTF towards an OCS node) is
mandated through configuration file. Default value "enable: auto" will
only make use of it in case a Diameter peer announcing support for the
Credit-Control Application is found.
Upon subscriber session creation, and after auth check over Gx, the SMF
will create a Gy session with the OCS and only after that step the SMF
will accept the session back to the subscriber.
The OCS may then grant some traffic volumes/time and ask to be notified
back with updated measurements.
In order to get the measurements, the SMF relies on PFCP URR configured
to the UPF through Session Repoort Request messages.
When closing the subscriber session, the SMF will also terminate the Gy
session at the OCS.
So far only some specifics parts of the Gy interface as well as the PFCP
side are implemented. Those should be enough to at least have
volume/time thresholds granted by the OCS, which then will be able to
track subsriber resource use.
This patch doesn't implement the OCS side of the Gy interface, that's
left as a future exercise. The interface was tested using an OCS
emulator implemented in TTCN-3 [1]
[1] https://cgit.osmocom.org/osmo-ttcn3-hacks/
TODO:
* Use an event for the report, like SMF_EVT_N4_TIMER?
* Properly set Service identifier in Gy CCR
* SMF: Properly set pkt/octet volumes in Gy CCR
** Update when receiving PFCP Modify Response.
* Figure out best way to require Gy through config file in open5gs-smfd.
* Create a new sess-sm.c which handles smf_sess_t state through
Gx+Gy+PFCP creation, modification and tear down. This way we can do
stuff in parallel, for instance Gx+Gy. It will alsoavoid duplicating
some code paths due to Gy being optional.
Pau Espin
Supreeth Herle
Sukchan Lee