the created RLC PDU was too large to fit inside the MAC grant
because only the header room for the short L field was used.
The patch determines the correct size before passing the opportunity to RLC.
It also improves logging in error case by using the MAC logger instead of
stderr/stdout when error occurs.
building on the previous refactor this patch now adds support
for peridoic BSR reporting (using short BSR). It furthermore does
the following changes:
* add BSR packing
* add proc_bsr_nr unit test
* move mac_nr test code into test folder under src (needs to be done with other test code too)
we've checked the same when unpacking the subheaders but missed the
case where the payload was read beyond the PDU length, as has been
seen with a malformed RAR PDU.
detected with ASAN trying to write negative number of padding bytes.
The patch checks the calculated length and returns with an error
if the length is negative.
=================================================================
==5759==AddressSanitizer: while reporting a bug found another one. Ignoring.
m==5759==ERROR: AddressSanitizer: negative-size-param: (size=-6)
* Reorder DCI FORMAT enum
* Fix endianness issue
* Fix return codes in phy_ue_db
* Log members should be destructed after the layers.
* Add JSON metrics and Events. Add Alarm log channel. Simplify MAC metrics struct.
* Restore metrics_stdout change
the bug causes the BSR to return a bsr_idx of 0, i.e. no data
pending, when the buff_size was reported to be 1 B only.
Instead, the UE should return BSR idx 1, i.e. between 0 < BSR <= 10.
LBSR packing is fine but this makes the eNB do wrong things
because it thinkgs LCG2 has no or too much data to send.
LCG2 is our default LCG for DRB1. One occasion we saw the issue
is doing full rate TCP DL which requires quite a bit of ACK traffic
back to the sender. With the BSR for LCG2 being wrong, providing
UL grants was delayed and so the TCP DL throuhgput was very low.
In the log below we see that the buff_size[2]=1 so there is data to send.
Interestingly, the packing was correct so Wireshark displays it correctly.
But the unpacking not, as can be seen in the MAC log below which reports
0 buffer state for all LCGs
22:08:54.804792 [MAC ] [I] [ 5084] pdu_get: sdu_len=1212, channel.sched_len=1213, bsr.buff_size[2]=1
22:08:54.804840 [MAC ] [I] [ 5084] UL LCID=3 len=1212 LBSR: b=0 0 0 0