It might be desirable to run the UE without superuser rights. More
concretely, it might run without NET_ADMIN. In this case, various
corresponding operations on the TUN socket fd might fail. In this
commit,
- improve error reports to make them more clear
- do not automatically exit(1), but return from the function to ensure
continuity of the softmodem
Introduce the structure nr_pdcp_integrity_data_t and adapt code to use it.
Note: in nr_pdcp_sdu_t we keep the 'count' variable (which is also present
in nr_pdcp_integrity_data_t). They represent the same value, but 'count'
in nr_pdcp_integrity_data_t is to be specifically used for integrity while
the other one has other uses, so it's better to keep it.
The use of security_mode_completed in the PDCP entity was a hack.
Plus it was not working at all with the deregistration request
when nea2 is used, sent when doing ctrl+c in the nrUE.
So let's remove it.
And let's handle activation of integrity and ciphering more in
accordance with what 38.331 says. SecurityModeComplete has to
be sent integrity protected, but not ciphered. Only after should
the ciphering be activated. (See 38.331 5.3.4.3.)
- PDCP reestablishment on CUCP (DRBs) triggering Bearer Context Modification procedures over E1
- Performing PDCP reestablishment for requested DRBs on CUUP
- Introduced function to notify re-establishment to CU-UP
- removed call to PDCP reestablishment for the DRBs on CUCP (it's done on CUUP)
cuup_notify_reestablishment:
- to fetch PDU session to setup in E1 following logic as in e1_send_bearer_updates
- fill bearer context modification request with stored F1-U tunnel information
during E1 reestablishment, otherwise it would initialized to 0 by default
- update GTP tunnel with the stored configuration after E1 reestablishment
- triggered by RRC reconfiguration events according to clause 5.3.5.6.5 of TS 38.331
- This procedure does QoS flow to DRB mapping according to clause 5.3.1 of TS 37.324
- QoS flows to DRBs to be released are also handled
- e2_ran_func library divided into e2_ran_func_cuup (CU-UP only) and e2_ran_func_du_cucp_cuup (DU, CU, CU-CP and gNB-mono)
- GTP SM is not yet implemented in CU-UP -> CU-UP doesn't store PDU session information
- PDCP SM support for gNB-mono, CU and CU-UP
- KPM SM support for all node types (DU, CU, CU-UP, CU-CP and gNB-mono)
remove several unused files
remove mem_block_t that is never used in a different way than a simple heap buffer
move up IP address type and remove duplications of the same struct declaration
cleanup means:
- typo: susbend -> suspend
- call nr_pdcp_manager_unlock() where needed
- simplify LOG_XX (remove __FILE__, __LINE__, __FUNCTION__)
note:
nr_pdcp_release_srb() and nr_pdcp_release_drb() don't use
nr_pdcp_release_drb() because they modify the arrays, so
it does not make sense to "abstract" the accesses to
->srb and ->drb.
Security part needs to be checked, may fail to work.
But if it fails, it was probably not working before either.
This commit also contains adding 'static' to nr_pdcp_entity_release()
and nr_pdcp_entity_delete() (it was too complicated to do a separate
commit for this).
We also update stats in free_rx_list() (again, too complicated for
a separate commit).
openair2/RRC/NR/rrc_gNB.c probably needs some more work, it is a
bit ugly to reestablish all the drbs without checking if they
exit. It will generate warnings at runtime. I didn't do it because
I don't know the proper way.
This commit repairs the reestablishment after the introduction of the CU
UE ID in the CU, different from the DU UE ID. Now, the CU uses an
identifier different from the RNTI, used in the MAC, to refer to UEs.
To repair the reestablishment, a number of changes needed to be
introduced:
- Handle old_gNB_DU_UE_id in MAC
The MAC handles the old_gNB_DU_UE_id field in the DL RRC Message. The
commit adds encoding/decoding of the field. The MAC will drop the old
UE, but retain the CellGroup of the corresponding UE(!). Because a UE
releases the spCellGroup on reestablishment, the MAC does the same; it
needs to reapply the old configuration after a reconfiguration. For the
latter, introduce new variables to keep a "future" CellGroupConfig to be
applied (reconfigCellGroup) and a flag (expect_reconfiguration) that
applies the CellGroupConfig if a DL RRC Message transfer on DCCH, which
is assumed to be the reconfiguration.
- Add RNTI change in RLC
The RLC needs to reuse the old UE context. Hence, we simply change the
RNTI in the old context, and delete the new one.
- No PDCP UE ID change
The previous implementation of the PDCP used the RNTI; hence, the ID
needed to be switch (as above for the RLC). Since the PDCP now also uses
the CU UE ID, no identifier change is needed, and we remove all
corresponding code.
- No MAC modifications/update from CU
As foreseen by the spec, the CU does not modify or change the
cellGroupConfig in the RRC during reestablishment. This change will be
generalized in the future to all of the RRC. Also, the
nr_rrc_mac_remove_ue() function has been removed: the MAC handles any UE
changes autonomeously, without being triggered from the RRC explicitly.
- Remove reestablish_rnti_map
The RRC does not use RNTIs for UE identification. Hence, a
reestablish_rnti_map to link two UEs to each other is not necessary
anymore.
After a reestablishment, the PDCP sequence number counters have to be
reset. Implement an API to allow the RRC to reset the sequence numbers
for a particular UE in the case of reestablishment
- The CU/DU UE ID is used in DL RRC Message Transfer
- Note: The CU UE ID currently is still the RNTI
- on every DL RRC Message, the DU verifies that the UE exists
- Refactor RRC: common function to forward protected SRB PDUs
Bartosz Podrygajlo