After a new connection from RRC IDLE, an integrity failure occurs. This
commit is addressing this issue to pass the integrity check.
* Reset ciphering and integrity algorithms when going into RRC IDLE
* Use uplink NAS COUNT in Registration Request for initial KgNB derivation
* Temporarily deriving UP protection keys in Registration Request
* Note: AS SMC handling should be done according to 33.501 §6.8.1.1.2.2
> In N1 mode, upon indication from lower layers that the access stratum
connection has been released, the UE shall enter 5GMM-IDLE mode and
consider the N1 NAS signalling connection released (3GPP TS 24.501)
* NAS -> RRC: RRC receives an ITTI message with NAS 5GMM indication message
containing the 5G-S-TMSI derived from NAS GUTI
* 5G-S-TMSI is stored in the RRC instance and to be later encoded in the RRCSetup
Refactor and extend NAS Registration Request
Extended NAS Registration Request generation and encoding according to
8.2.6 of 3GPP TS 24.501. Main topics:
- NAS Registration Type
- NAS KSI
- integrity protection
- NAS container encoding
Improvements:
- Add 5GMM Modes in NAS
- Introduced 5GMM state machine
Fixes:
- add 5GMM Capability IE to Registration Request
- closes#881, #819
* Without a valid 5G NAS security context:
* Send REGISTRATION REQUEST with cleartext IEs only.
* After activating a security context via Security Mode Control:
wrap the entire REGISTRATION REQUEST (with both non-cleartext and cleartext)
in a NAS message container IE, include it in SECURITY MODE COMPLETE
* With a valid 5G NAS security context:
* If non-cleartext IEs are needed, wrap the entire message in a NAS message container IE and cipher it.
* If only cleartext IEs are needed, send the message directly without the NAS message container IE.
* this commit is enabling the handling of non-cleartext IEs in the NAS Registration Request message
according to 24.501, 23.502
* send the full Registration Request message in the NAS Container of the SECURITY MODE COMPLETE
* send the non-cleartext IEs in the NAS container of the Registration Request
closes#881
* send integrity protected Initial NAS Message when UE in 5GMM-IDLE mode has valid current 5G NAS security context:
> According to 4.4.2.5 TS 24.501:
> when a UE in 5GMM-IDLE mode establishes a new NAS signalling connection and has a valid current 5G NAS
> security context, the UE shall transmit the initial NAS message integrity protected with the current 5G NAS security
> context and further protect this message as specified in subclause 4.4.6.
* set NAS key set identifier IE to "no key is available (UE to network)"
* previously set to 1 which has no impact
* set now to 111 in order to trigger new authentication
* See 9.11.3.32 of 3GPP TS 24.501
* Do 5GS Registration Type "mobility registration updating" when 5GMM state is De-registered
* added fgs_mm_mode_t enum
* added struct member to NAS
* modes: FGS_IDLE, FGS_CONNECTED
* according to 5GS mobility management (5GMM) modes 5.1.3.2.1.1 of TS 24.501
NAS 5GS refactor
The goal of this MR is to reorganize the NR NAS code into:
- enc/dec library functions (5GS, 5GMM, 5GSM, NR_NAS_defs.h,
nr_fgs_nas_lib.c)
- handlers and callbacks (nr_nas_msg.c)
The following changes are introduced:
1. migrate 5GS enc/dec lib (5GMM and 5GSM) to a dedicated folder
2. add a nested CMakeLists structure
3. refactor NR NAS enc/dec functions
4. refactor NR NAS messages struct definitions
5. remove most of dependency from NAS LTE
6. further refactor of PDU Session Establishment Accept processing to
separate enc/dec from handling
7. made naming of 5GS definitions consistent whenever necessary
8. cleanup unused code
9. remove redundant struct definitions
Also:
1. fix decoding of AMF Set ID in 5G-S-TMSI UE identity
2. replace Byte_t directly with uint8_t
previously we had decodeRegistrationAccept acting as a handler and calling
decode_registration_accept to do the decoding. However the logic was mixed
between the two functions, the naming was confusing and the code was hard
understand. The goal of this commit is to simplify the code, improve
readability and maintainability, while adapting the relevant function
to the new OAI NAS libs structure.
To this purpose:
* move enc/dec logic to NAS lib openair3/NAS/NR_UE/5GS/5GMM/MSG/RegistrationAccept.c -
the logic of parse_allowed_nssai, get_allowed_nssai has been moved to
decode_registration_accept and decode_nssai_ie
* add decode_nssai_ie and use it for both Allowed/Configured NSSAIs list (IE handling was added)
* do processing in the handler handle_registration_accept
* simplify the code by removing nested calls
* improve handling of PDU length
Currently only Registration Result, 5GS Mobile Identity, Allowed/Configured NSSAI
are decoded. The other optional IEIs are skipped (only the length is processed).
* the last 6 bits of the GUTI represent the AMF Pointer
* the AMF Set ID is 10 bits long
* the Registration Accept message received from the network contains the GUTI
which, when properly decoded, will be used in any possible following Registration Request
* use defines whenever possible
* introduce a switch to handle security type. Currently only integrity protected and ciphered
is handled, however the idea of the switch is to make the code ready for the future when
different security types will be handled and different actions should be taken based on that.
* define NAS_INTEGRITY_SIZE
* the goal of this commit is to refactor capture_pdu_session_establishment_accept_msg
into a decoding function
* PduSessionEstablishmentAccept.c is in the 5GSM library and shall only do encoding operations
* handling of PDU Session Establishment accept message is done in nr_nas_msg.c
* adopted new NAS decoding functions in the process
* improved QoS rules decoding
* convert getShort into a macro and add to NAS utils
as per legacy code, the NAS functions in nr_nas_msg.c were encoding
the header in the plain header contained in MM_msg
(e.g. plain -> mm_msg -> header in fgs_nas_message_t). The same
header was encoded in the mobility management message contained
in the same struct (e.g. plain -> mm_msg -> registration_request
-> protocoldiscriminator). As this was more complicated than
necessary, the goal of this commit is to simplify the code and
improve readability. Namely:
* Refactor MM_msg into fgmm_nas_message_plain_t to contain
(1) 5GMM Header
(2) 5GMM Payload union
* Use fgmm_nas_message_plain_t and fgmm_nas_msg_security_protected_t
in the 5GMM NAS procedures
* Remove NAS header IEs from 5GMM messages structs and use
the header in fgs_nas_message_plain_t.
This reduce also the repetitions of header members in each
of the 5GMM messages structs.
* Rename struct to distinguish between 5GMM and 5GSM
* Remove fgs_nas_message_t and nas_msg_header_t,
use directly basic 5GS struct definitions, simplify the code
* The callbacks in nr_nas_msg.c are now doing
(1) encode header with the common NAS lib
(2) encode contents with the 5GMM libs
* improve code readibility in the process
* replace encoding code with proper functions from the lib
* remove unnecessary header members in struct definition
this commit removes last enc/dec code in nr_nas_msg.c
* move enc/dec definitions to NR_NAS_defs.h and add new lib file nr_fgs_nas_lib.c
both used by nr_nas_msg.c
* move utility macros to fgs_nas_utils.h: this can be used in all the 5GMM, 5GSM lib files
* use nr_nas_msg.c for handlers/callbacks only, it should call the enc/dec
functions in nr_fgs_nas_lib and in the 5GMM, 5GSM libs
* 5GMM, 5GSM libs should only do the enc/dec of the NAS message contents
* move defines to openair3/NAS/NR_UE/nr_nas_msg.h as they are
only used in nr_nas_msg.c
* made naming of all message types consistent, using the same
prefix for all
* the only function used from nr_common.c is servingNetworkName which is
used in nr_nas_msg.c, so it was moved to the latter file and its scope
was reduced
Every NAS 5GS message can have 3 different headers: (1) security protected
(2) 5GMM plain (3) 5GS plain;
According to 3GPP TS 24.501:
> 4.2 Coordination between the protocols for 5GS mobility management and 5GS session management
> A 5GS session management (5GSM) message is piggybacked in specific 5GS mobility management (5GMM) transport
> messages. To this purpose, the 5GSM messages can be transmitted in an information element in the 5GMM transport
> messages.
A PDU Session Establishment accept is a 5GSM message and as such it is contained in a 5GMM
transport message. The code in capture_pdu_session_establishment_accept_msg is reflecting this.
The message is thus expected to have: (1) Security protected 5GMM header (2) Plain 5GMM message
(3) 5GSM Payload Container (4) Plain 5GSM message.
5.4.5 of 3GPP TS 24.501: also says:
> The type of the payload is identified by the Payload container type IE and includes one of the following: a) a single 5GSM message;
Thus, a 5GSM is not the only possible payload of a NAS transport message.
This commit is focusing on the refactoring of the structs definitions and adaptation of the CMakeLists.
Based on the above:
* Move NR_NAS_defs.h to 5GS subfolder in NR_UE
* Move NAS FGS structs and definitions to NR_NAS_defs.h
* Rename mm_msg_header_t to fgmm_msg_header_t
* Remove duplicated NAS struct definitions
(1) kept fgs_nas_message_security_header_t over security_protected_nas_5gs_msg_t
(2) Kept fgsm_msg_header_t over fgs_sm_nas_msg_header_t
* Remove unused definitions, structs, functions in the process
This commit is introducing the following macro changes:
(1) Migrate NAS 5GS lib files to a new 5GS subfolder in NR_UE
and organize NAS 5GS lib messages into 5GMM and 5GSM subfolders.
A nested CMake structure was implemented and CMakeLists.txt were
added whenever necessary. This is effectively separating 5GS
libraries from LTE libraries.
(2) In order to simplify the separation of 5GS libs from LTE libs,
remaining dependencies from NAS LTE (e.g. nas_ue_task.c, ue-idx-standalone)
were removed in the process
(3) ExtendedProtocolDiscriminator.c/.h and SpareHalfOctet.c/.h were deleted
and affected types were replaced with simple integer types
(4) Cleanup: unused definitions and libs (e.g. LIB_5GNAS_GNB)
were removed
(5) Update doc/Doxyfile
(6) clang-formatted the migrated files in the process
(7) Update includes of headers in affected files
- Refactor SCTP Association Response Handling
- Unified function for both CU-CP and CU-UP handling
- CU-CP: Notifies RRC of E1 connection loss with CU-UP
- CU-UP: Initiates a new SCTP association request to regain E1 connection
- this fix will prevent issue #878 from happening
- Send list of PDU Session Resources to Failed Setup in the (PDU Session
Resource/Initial Context) Setup Response
- depending on different failure scenarios
- e.g. (#878) when No CU-UP is associated and still the CU-CP receives a PDU
Session Setup Request
- add relevant functions to handle NGAP Setup Response messages with failed
list of items
- this is an extra failure handling to make #878 is handled if it ever happens
again
- NGAP Cause Refactoring
- Refactor struct for NGAP cause group and value
- Add extended radio network cause enumeration values
- Refactor redundant code into a new NGAP cause encoding function
- Minor logging, function descriptions improvements
Closes#878
* 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
Guido Casati