Remove function pointers that were used in the past to implement the
F1(-U) interface in 4G, i.e., to have different functions to handle
split/monolithic operations. As we don't have F1 in 4G anymore (see
commit 9dc2282249), we don't need the
function pointers anymore.
On that occasion, rename the 5G functions by prepending nr_ to them;
this allows to refactor the interface in 5G further (which is not the
focus of this changeset).
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
To allow to send F1 messages to multiple DUs from the CU, we need to
send these messages via different assoc_id (SCTP association ID,
basically akin to a file descriptor). Currently, the assoc_id is stored
in a context at the F1 module and retrieved in
f1ap_itti_send_sctp_data_req().
To facilitate a later change towards indicating (from the RRC) to which
assoc_id (hence, DU) to send a message, we refactor all
CU_send_*()/DU_send_*() functions to take the assoc_id as a parameter to
which to send messages. In this commit, we then pass the assoc_id from
the context. A later commit changes this (at the CU) to pass the
assoc_id from the message to be sent.
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.
The UE had a list of known UEs. With the introduction of a separate
module for F1 UE ID handling that is also used in monolithic (to
separate CU UE ID from DU UE ID), this functionality is not needed, and
deleted in this commit.
- 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
Previously, in f1ap_decoder.c, we asserted if we did not know a message.
Apart form decoding, we did not do anything in that file.
Additionally, in f1ap_handlers.c, we were also checking for an unknown
message, and printing a warning if a handler is not known.
This commit moves the F1AP message decoding to f1ap_handlers.c, and
deletes f1ap_decoder.c. In summary, we don't assert on an unknown
message, and compile less files. The rest is unchanged.
Creates function that have nr_pdcp_ prepended to their name, and change
the signature of some functions for the 5G PDCP:
- nr_pdcp_layer_init()
- nr_pdcp_data_req()
- nr_pdcp_remove_UE()
- nr_pdcp_config_set_security()
- nr_pdcp_remove_UE()
- Make separate functions for nr_pdcp_data_req_srb/drb()
The simulators have been changed: due to linker errors that would arise
otherwise, a lot of functions are defined in them to avoid such errors.
Some functions are also defined in header files; in this commit, we
define most functoins in nr_dummy_functions.c, which is compiled in, not
by including the C file, but by adding it to the target in
CMakeLists.txt
- nr_dlsim+nr_ulsim need NR_IF_Module_init(), so it cannot be in
nr_dummy_functions, but the others need it
- Link correcr NR_IF_Module_init() into these simulators, and reduce
overall link list
- Correctly link remaining simulators
francescomani