E1 Setup enc/dec library and unit test
This MR is adding a library for E1 Setup enc/dec functions:
- E1 CU-UP Setup Request
- E1 CU-UP Setup Response
- E1 Setup Failure
and relevant unit tests
* this function is used by both CU-CP and CU-UP
* it behaves differently depending on the type of E1 instance:
CU-CP: inform RRC of E1 connection loss with CU-UP
CU-UP: trigger a new SCTP association request by sending an ITTI to the CU-UP task
* after receiving the E1AP register request, the CU-UP will send a new association request to
SCTP until new E1 connection is achieved by sending a TIMER_HAS_EXPIRED message to the CU-UP
task. The function e1apHandleTimer() is basically triggering a new E1 association request
until new E1 connection is achieved
* print SCTP association state in e1ap.c whenever needed
Related to #878
Rewrite sctp_create_new_listener() to use getaddrinfo() to look up
IPv4/IPv6 addresses via a common interface. This allows to use e.g. DNS,
and enables the SCTP library to listen on IPv6 ports.
To support the above, the corresponding message is changed to not take
an IPv4 address on 4 bytes (and separate IPv6), but a single name that
will be resolved via getaddrinfo()
The previous init message used to allow multiple IPv4/IPv6 addresses;
since this is not used anywhere, remove the corresponding functionality.
Modify all uses of this ITTI message to copy te SCTP init bind addr into
ITTI message.
- 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
- many structs and definitions are overlapping between the two different E1 procedures
- introduced naming specific to E1 Bearer Context Modification to improve readability
- grouped SDAP and PDCP configuration IEs for better reusability and readability
- introduced functions to set and get default PDCP config (DRBs and Bearer Contexts)
find_or_next_pdu_session:
- find_or_next_pdu_session refers to the E1 Bearer Context Modification Request
-- therefore it has to return pdu_session_to_mod_t* and takes in input e1ap_bearer_mod_req_t *
see !MR2545 for more context
- CU-CP replying to the CU-UP with a Setup Failure message in case of unsuccessfull E1 Setup Request
- message is decoded by the CU-UP, and stops the process
- Implement: Extend the F1 encoding and decoding with Qos
- Implement: E1 decoding for QoS
- Fix: Modify the UE_MODIFICATION_REQUEST_MSG towards DU to contain QoS info based on E1AP context response
- Fix: Modify the E1AP and F1AP message structures
- Fill the Qos configuration to send to MAC
3GPP has the concept of a gNB-CU-UP ID and a (separate) gNB ID (for gNB,
CU-CP). This commit introduces the gNB-CU-UP as a separate ID that has to be
set in the configuration file when running as a CU-UP. For the
CU/monolithic gNB, it is optional (but needs to be the same as the
gNB-ID if specified).
The CU-UP ID is necessary, as some entities, e.g., the e2 agent, need to
signal both IDs, e.g., to reconcile a CU-CP and (multiple) CU-UP(s)
belonging together.
This commit introduces the capability to handle multiple CU-UPs. It uses
a RB tree and puts the CU-UPs into the tree. Upon the connection, it
associates UEs to CU-UPs in a round-robin fashion.
The E1AP Setup Request contained the network configuration (IP address,
ports) as well as the actual E1AP Setup Request application data
(Supported PLMNs, ...). This has the drawbacks that
- The E1AP Setup Request is stored to retrieve IP addresses in the E1AP
module, which is confusing as the Setup Request, per standard, has no IP
info
- The CU-CP received an E1 Setup Request for configuration during start
up, but it did not actually receive such Setup Request, but merely the
IP configuration to set up the socket
This commit splits the E1AP Setup Request into a "real" Setup Request
for application data, and creates a new type e1ap_net_config_t to group
all IP configuration data. Further, a new ITTI message type
E1AP_REGISTER_REQ is introduced to group both types. What happens is
- RCconfig_NR_CU_E1() reads both E1AP application-level data and IP
configuration, as previously
- The data is sent to the CU-CP. It discards the E1AP Setup Request
data, and only uses the network configuration to set up the socket
- The data is sent to the CU-UP. It uses the network configuration to
connect to the CU-CP, and then sends the E1AP Setup Request to the
CU-CP.
Currently, the CU-CP still stores the Setup Request locally, which will
be changed in the next commit to send it to the RRC.
Robert Schmidt