We don't work much on asn1c. The version we use has several bugs.
There is an active community out there that fixes bugs and improves
asn1c. Let's use their version.
The GTP module is common for 4G and 5G. It hardcodes the functions to
call when creating S1U and NGU tunnels. The S1U case is both applicable
for LTE and NR (NSA), which until now was not a problem as the PDCP data
forwarding functions where called pdcp_data_req. The issue is that in this
branch, the NR PDCP functions have changed to nr_pdcp_data_req_drb().
When setting up a GTP tunnel, we now pass the PDCP data forwarding
functions into GTP, since the caller knows whether it is in 4G or 5G,
but GTP itself does not.
OAI is riddled with boolean_t, FALSE, TRUE, etc. This makes no sense, as
there is a standard bool type, and could lead to nasty bugs if a
definition of a bool is non-standard (0 == false, true == !false). This
commit removes all non-standard bools in the whole project.
At this point we are successfully able to build.
Additionally, we can run the scenario,
however, it does not pass. It seems that the gNB
is not connecting to the proxy correctly. Just
wanted to push the progress so far. FYI, the items
that had to be changed to correct the linking issues
were the following:
- mac_rrc_data_ind_ue vs. nr_mac_rrc_data_ind_ue
- rrc_data_req vs. nr_rrc_data_req
- mac_rrc_data_req_ue vs. nr_mac_rrc_data_req_ue
- rrc_data_req_ue vs. rrc_data_req_nr_ue
- rrc_data_req vs. nr_rrc_data_req
The listed functions should be declard in the LTE/NR
UE directory depending on the functionality. Several
were mixed. i.e.: LTE functions being called in NR UE.
Also, removing siWindowLength, siWindowLength_int,
SIBType, SIBPeriod, and siPeriod_int from the NR UE RRC.
These variable were not used in the NR UE and are defined
for LTE only.
Lastly, in the NR_IF_Module.c of the NR UE, the global
variable def_dci_pdu_rel15 is not accessible. Need to
revisit this. For not it is commented out.
Updated the configuration files. Added a sleep to
ensure that the LTE UE gets attached to the EPC
before the bearer is modified to be gNB. Updated
the ifconfig tunnel up command to be brought up
by the NR UE socket when in NSA mode. Lastly,
started the gNB PDCP layer in S1 mode.
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)
Laurent THOMAS