This commit introduces several enhancements in X2AP and RRC to deal
with ENDC. The main goal is to deal with UE's on/off and with various
errors.
The following work is included:
- DC prep and DC overall X2 timers
- X2 messages for UE release and DC timers' timeout
Open problems:
- what to do when the UE sends an scg Failure? This commit removes
the UE. And this removal may not be correctly done
- UE removal in the gNB's PHY layer (a next commit is coming,
but it is hackish and will need a rework)
Some deadcode was removed.
The implementation of the ID management is not finished.
It will only work if the handover is successful. No error
recovery has been done. For error recovery, we need to
implement the X2AP timers. As it is, in case of error, an ID
might very well never be released.
It has been tested with 1 and 2 UEs doing handover more or less
at the same time.
- manage target eNB based on target cell id received by measurement report
for Handover Request
- manage source eNB based on association id for Handover Request Ack
- use only x2ap instance and not x2ap data instance points to x2ap instance
With the introduction of X2AP into develop, the UEs now have to regularly
send measurement reports.
In the logs of the eNB, we see:
[OSA] Mismatch found in integrity for algorithm 2,
got e0.a0.c2.66, expecting a5.9c.cb.57
[PDCP] [OSA][RB 1] eNB failed to validate MAC-I of incoming PDU
This is a bug in the PDCP layer that uses wrong parameters to compute the
integrity.
This commit fixes this bug.
The function pdcp_is_rx_seq_number_valid was removed. Its processing
has been directly integrated into the function pdcp_data_ind.
The function pdcp_mark_current_pdu_as_received is not called anymore.
Its processing was not used later on, so as of today, not calling it does
not introduce any functional change.
The function pdcp_validate_security takes now as parameters both
SN and HFN. Same for the function pdcp_get_next_count_rx.
Useless constants PDCP_SN_5BIT, PDCP_SN_7BIT and PDCP_SN_12BIT have been
removed.
The compilation option ENABLE_SECURITY has been removed. It's now always
on. (This may impact some use cases.)
The PDCP for DRB using RLC AM is not correct. It was not correct before
this commit (apart from the integrity bug). We should deal with a list
of PDUs and transmit packets to upper layers as detailed in the specs.
Today we transmit the PDU as soon as we get it. We don't care about
duplicates, in-order delivery, timeouts.
Also, we don't deal with "PDCP re-establishment". Not sure how that impacts
the software.
And, last but not least, there is still no ROHC.
--> openair2/LAYER2/MAC/eNB_scheduler_primitives.c is still old (not from issue394_fix_cppcheck branch)
Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>
This commits isolates the S1 UE Ctxt Rel Complete and GTP Tunnel Delete
Requests in functions and calls these function in the original place
(rrc_rx_tx()). The same functions are then used in the F1 UE Ctxt Rel
Complete handler to perform the same functionality, i.e. forward the UE
Ctxt Rel Complete message to the MME and free outstanding resources (RRC
context, GTP tunnels, S1 context).
Laurent THOMAS