Add F1 Handover procedures
- Clean up at RRC and MAC
- Add DU handover procedures, completely handle CellGroupConfig at DU
- Add CU handover procedures
- Maintain reestablishment working between/after handover
- Changes at UE to resync on different frequency DUs
Instructions: see doc/handover-tutorial.md
Things not implemented/open/missing: see #855
Implement the Transmission Action Indicator F1AP forwarding logic, and
add it to the F1 internal representation structure. After the
transmission interrupt timer (during which SRB1 can send messages), the
UE will be out-of-sync (we assume it's not there anymore).
Co-authored-by: batuhanduyuler <batuhan.duyuler@firecell.io>
Co-authored-by: rmagueta <rmagueta@allbesmart.pt>
Implement the HandoverPreparationInformation F1AP forwarding logic, and
add it to the F1 internal representation structure.
No logic is implemented in this commit.
Co-authored-by: batuhanduyuler <batuhan.duyuler@firecell.io>
Co-authored-by: rmagueta <rmagueta@allbesmart.pt>
Currently, sD has not been allocated, so the octet string is empty. Fix the
allocation to correctly write&read NSSAIs in UE context setup/modification
request messages.
The existing check for the initialization of GTP is wrong; GTP returns
-1 if it could not initialize. Correct this, such that the DU will stop
if GTP cannot be initialize.
If we continue, the DU is requested to set up a GTP tunnel; because GTP
is not initialized, it assumes it is in monolithic/no F1, and does not
set up a tunnel. The F1 UE Context setup response encoder then fails
with this assertion:
Assertion (tnl->teid > 0) failed!
In DU_send_UE_CONTEXT_SETUP_RESPONSE() ../../../openair2/F1AP/f1ap_du_ue_context_management.c:415
Exiting execution
../../../openair2/F1AP/f1ap_du_ue_context_management.c:415 DU_send_UE_CONTEXT_SETUP_RESPONSE() Exiting OAI softmodem: _Assert_Exit_
Aborted
Closes: #853
* _F1_EQ_CHECK_GENERIC can be used to check the equality of two different members of F1AP structs
and return `false` if the condition is not met.
When the condition fails, the macros will print a debug message to the standard error stream,
including the function name, line number, and the provided format string and arguments.
Add a new target f1ap_lib that groups F1AP ASN.1 encoding&decoding for
messages defined f1ap_messages_types.h. The objective is to, for each
F1AP message,
- add encoder&decoder (similar to what already exists, but without
mandatory message sending afterwards)
- eq_X() function that checks two messages for equality (to be used
mostly in tests)
- cp_X() function that deep-copies a message, e.g., to be used when
sending ITTI messages, instead of manual copying done currently
- free_X() function that frees the memory associated to a memory, to
avoid memory leaks.
Each message will be tested, notably that encoding&decoding as well as
copying yield identical messages.
The actual message encoding & decoding, tests, and their use will be
done in the forthcoming commits.
The currently used type does not cover all possibilities. While we don't
encode&decode them, it might still be good to be able to express it, so
introduce the new type.
Co-authored-by: Guido Casati <hello@guidocasati.com>
Robert Schmidt