The necessity of SOstart/SOend was understood after email exchanges with
David Breaux <davidbreaux67@gmail.com>.
See openair2/LAYER2/rlc_v2/tests/test46.h for some details.
Basically if we NACK without SOstart/SOend then the other end of the RLC
channel will consider all the bytes as NACKed and will have to resend them
all. If another status is then reported before all the bytes are sent,
and because we don't use SOstart/SOend this status will NACK all the bytes
again, then all the bytes are to be sent again. And the cycle repeats.
It will end with a max retx reached (which triggers RLF, Radio Link Failure).
The function put_bit in openair2/LAYER2/rlc_v2/rlc_pdu.c has been changed
too, maybe introducing some performance issues.
- enabled procedures that were already called for phy-test mode
- enabled setup of DRB for the current C-RNTI
- enhanced information, debugging and warning logging at MAC/RLC/PDCP level
RLC has timers. We need to keep track of time. We chose to not use
realtime but 'processing time'. That is we send a tick to RLC for every
subframe when it is processed by the softmodem. Before this commit we
used to increase time in the function mac_rlc_status_ind which may not be
called every subframe (especially in TDD mode). So we need another way
to keep track of time.
We introduce rlc_tick() and call it in eNB_dlsch_ulsch_scheduler, which
is called every subframe, both in FDD and TDD.
We also call rlc_tick() in the function ru_thread_synch() because
pdcp_run() and rrc_rx_tx() are called there too.
It may not be the best solution. To be revised if needed.
Note: the UE has not been touched. Some modification is needed for the UE
too, most probably.
also correction for Circular Dependency Protection on header files
also correction on the banner check
Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>
Minor fixes, doesn't change anything. Not sure these are 'bugs' either,
but let's be polite with coverity scan...
One thing was not changed.
Coverity scan says:
*** CID 357991: Memory - illegal accesses (USE_AFTER_FREE)
/home/carabe/raphael/openairinterface5g/openair2/LAYER2/rlc_v2/rlc_entity_am.c: 507 in tx_list_remove_sn()
501 } else {
502 prev = cur;
503 cur = cur->next;
504 }
505 }
506
>>> CID 357991: Memory - illegal accesses (USE_AFTER_FREE)
>>> Using freed pointer "head.next".
507 return head.next;
508 }
509
510 void cleanup_sdu_list(rlc_entity_am_t *entity)
511 {
512 rlc_sdu_t head;
But as far as I understand, there is no problem. We don't access
head.next at all if it has been freed. Or is there some aliasing
going on there (pointer aliasing)? I doubt it. False positive?
Limitation: this fix only works if there is only one eNB,
because we force module_id = 0 in the function deliver_sdu where
(as the code is today) we have no way to know which module_id is
concerned. More generally, the rlc v2 does not work with more than
1 eNB.
The old method was wrong.
The new method is better, but not accurate, especially when the
TX buffer contains SDU of size > 2047 bytes.
Plus it's probably too slow.
To be refined at some point.
This commit introduces an alternative RLC implementation
based on 36.322 version 8. AM and UM done, TM not done.
See openair2/LAYER2/rlc_v2/TODO for missing parts.
rmagueta