Prior to this commit, it might happen that the gNB used TDA 0 (Start 0
len 13) for mixed slot, in which case the UE could not send msg3
(because a mixed slot has less than 13 symbols).
Move decision of Msg2 allocation time instant from instance we receive
RA indication (only containing preamble time information) to actual RA
scheduler (containing current DL slot time). This has the advantage:
- if Msg2 cannot be sent, we might try in a later slot
- no timing-based problems were a RACH.indication FAPI message might
come late, we calculate a Msg2 frame/slot, but this instant has
already passed in the DL scheduler
- no assumption about slot_ahead (an L1 constant)
The previous code calculated and verified an SSB index; I am not sure
this code is correct or used. I leave the function
ssb_index_from_prach() (hence the gcc attribute), but remove any checks.
Similarly, the beam association list might be wrong. I deleted the
corresponding code.
Introduce the structure nr_pdcp_integrity_data_t and adapt code to use it.
Note: in nr_pdcp_sdu_t we keep the 'count' variable (which is also present
in nr_pdcp_integrity_data_t). They represent the same value, but 'count'
in nr_pdcp_integrity_data_t is to be specifically used for integrity while
the other one has other uses, so it's better to keep it.
The case securityModeFailure didn't seem to be implemented
properly, so I just removed it entirely.
The variable 'securityMode' did not make much sense, removed as well.
Plus for integrity, there was: securityMode |= 1 << 5 for nea1
and << 6 for nea2, which does not seem correct (I would expect << 4
and << 5 respectively), so it was properly incorrect.
'securityModeCommand->criticalExtensions.choice.securityModeCommand'
was accessed before checking that
'securityModeCommand->criticalExtensions.present'
is 'NR_SecurityModeCommand__criticalExtensions_PR_securityModeCommand',
which is wrong.
The tests 'securityMode >= NO_SECURITY_MODE' and 'securityMode != 0xff'
don't make sense/are unclear, so removed too.
So let's simplify this function, wrong in several places. And put
some AssertFatal() so that the code won't do weird things. The
AssertFatal() can be removed later and the function improved later
if needed. The case securityModeFailure can also be handled later,
but I think there is more work to do than just encoding the message
and send it to the gNB, so it's not bad to remove it for the moment.
The use of security_mode_completed in the PDCP entity was a hack.
Plus it was not working at all with the deregistration request
when nea2 is used, sent when doing ctrl+c in the nrUE.
So let's remove it.
And let's handle activation of integrity and ciphering more in
accordance with what 38.331 says. SecurityModeComplete has to
be sent integrity protected, but not ciphered. Only after should
the ciphering be activated. (See 38.331 5.3.4.3.)
francescomani