The currently used type does not cover all possibilities. While we don't
encode&decode them, it might still be good to be able to express it, so
introduce the new type.
Co-authored-by: Guido Casati <hello@guidocasati.com>
The F1AP UE context release procedure can happen in at least two cases:
1. core requested a release of a UE
2. CU requests DU a release of a UE without a core release (e.g.,
handover)
In case 1., the CU has to fully release the UE in the CU, then ack the
NGAP message from the core, whilst in 2., nothing of that should happen
after the DU acknowledges the F1AP UE context release cmd.
cuup_notify_reestablishment() used
&ue_p->established_drbs[drb_id]
to look up a bearer, which is wrong, because it should be drb_id - 1
as in the top of the loop. Also, it used the dedicated get_drb()
function; harmonize to use only this function.
A follow-up commit refactors the filling of information of DRBs to set
up in a separate function (to be reused for handover later). Hence, we
cannot store the DRB TEID/address in the same functions, because it is
a logically separate step, and might not always be available.
In e1_send_bearer_updates(), we send the DL (DU) TEID and address to the
CU-UP. Therefore, correct the variable names to reflect that the F1-U
information pertains to the DU.
Also, move the tunnel info update function f1u_dl_gtp_update() to a more
prominent place, and take the pointer to the struct containing the
"interesting" information.
A maximum RRC buffer size of 1024 might be very small. We should
increase it, but then the 5G RRC_BUF_SIZE does conflict with other
definitions. To make it unique, also rename to NR_RRC_BUF_SIZE.
Reorganize the sequence of checks done in reestablishment to make it
more logical:
- check conditions of request (correct C-RNTI)
- check conditions of DU (has MIB/SIB1, MTC)
- check the UE, and from which DU it comes
This will also help to extend it towards reestablishment coming from
different DUs in the case of handover.
OAI 5GC seems to have a bug, and occasionally might send a PDU session
setup request without having sent a UE context setup request, resulting
in no security context activated for a UE. This lead to an assertion in
rrc_gNB_process_e1_bearer_context_setup_resp().
To prevent the gNB from stopping, check if security is active before
triggering PDU sessions. If not, the gNB will reject PDU sessions.
Variable spCellConfig is only used in function rrc_add_nsa_user(). Make
it local to this function to prevent possible bugs (limit the possible
scope as much as possible).
- E2SM UE ID requires guami -> therefore RRC_CONNECTED state signaling
to RIC is now done after receiving Initial Context Setup Request
from AMF, which contains the guami info
- make it work for SRB or DRB
- adapt callers of this function
- cleanup key derivation: the User Plane keys are generated at some places
but are not used, remove the generation
Neighbor configuration can be given by gNB.conf
get_MeasConfig function is extended as it will prepare A2 / A3 Report
Configs. Single Meas Obj is used for all.
rrc_gNB_process_MeasurementReport function is extended to process A2 /
A3 measurement events. helper functions are written to fetch neighbour
cell informations from sequence containers.
(get_neighbour_cell_information, get_neighbour_config)
The starting point was the function do_NR_DLInformationTransfer() which
may deal with more than 256 bytes.
Then why not cleanup all the functions in the same file.
(And do a bit of formattting fixing while we're here.)
Then cleanup the callers of those functions.
Then, because of do_SIB23_NR() let's also cleanup in some
structures.
Not all the codebase was cleaned up, there surely remain some uint8_t
(and char/short/uint16_t) which are wrong.
In the case of PDU sessions in the NG UE context setup request, we first
have to set up security. Hence, in this commit, implement the "delayed"
set up of theses PDU sessions, and acknowledge the setup request after
reconfiguration, as requested by O-RAN.WG5.C.1-v11.
Trigger UE ctxt setup response for the case of "registration request"
(no PDU sessions in UE Context setup response), as mandated by
O-RAN.WG5.C.1-v11.
As of this commit, since we now send the UE security command as a DL NAS
message, there is no F1 UE Context setup request. Hence, instead of
sending a UE context modif request, send the UE context setup request
after the E1 bearer setup response (which logically also makes more
sense, as the E1 setup procedure comes before the F1 setup procedure).
This reverts commit 0f100a6e94, which
introduced a hack to possibly wait with a PDU session setup at the RRC
in case a RRC UE capability transaction (requesting UE capabilities from
a UE) was ongoing. This happened, as we delayed the UE capabilities to
after the first RRC reconfiguration; in that case, certain UEs were
requesting the next PDU session, and if RRC did not delay the new PDU
session (as requested from the core), this procedure might occur while
UE capability enquiry was ongoing, leading to failures in these
transactions.
The default RRC reconfiguration was previously sent after the security
mode command as a "first" RRC reconfiguration. However, it is simply not
needed, as it will be triggered through a subsequent reconfiguration
that also sets up DRBs.
Move the Measurement Config to the "other/dedicated" RRC
reconfiguration.
This reconfiguration would have forwarded a NAS PDU (typically a
registration accept). This is now done by a dedicated forwarding of NAS.
This reverts commit 4a7d7975ce.
Trigger the UE capability right after security mode complete, as
specified in O-RAN WG5.C.1-v11. Also, there is no "need" for the
"default" RRC Reconfiguration (it will come once PDU sessions are
requested), so remove this as well.
Previously, the CU sent the Security Mode Command as part of a UE
context setup request. This was done "because it was possible", not
because there was an inherent need to do this. However the LiteOn DU
does not like this, as it expects to also have a DRB in the UE context
setup request procedure, which is not always the case.
Hence, send the Security Mode Command in a normal DL RRC msg transfer
over F1. As of this commit, there is not UE context Setup Request (so it
might not work with all DUs), but the OAI DU is cool and does not care,
so RFsim still works.
This also aligns the CU's behavior with O-RAN.WG5.C.1-v11.
Finally, as of this commit, we do not trigger a UE context setup
request, so we cannot handle PDU sessions inside the initial UE context
setup request at the same time as the security mode command (which was
done previously before reaching this point). This will be fixed in a
later commit.
MeasTimingConfig may not come with F1 Setup Request: some DUs send it
with the DU configuration update. Handle this gracefully by checking for
MTC before using it.
- according to 5.3.7.4 of TS 38.331: 1> re-establish RLC for SRB1;
- gNB:
1) re-establish RLC for SRB1 in nr_rlc_update_id
2) re-establish RLC for remaining RBs concurrently with RRCReconfiguration
issue: gNB) in nr_rlc_update_id the gNB is re-establishing RLC for all
RBs at the same time when receiving RRCReestablishmentRequest
from UE
UE) according to the specs, the UE is re-establishing RLC for
SRB1 with RRCReestablishmentRequest the other RBs are
re-established during RRCReconfiguration (in our case in
nr_rrc_ue_process_RadioBearerConfig) when receiving
reestablishRLC IE in rlc_BearerToAddModList
RLC TX) this leads to RLC counters mismatch after re-establishment:
control PDUs discarded until max nb of retx is reached
and then UL failure occurs
Guido Casati