This includes:
- Adding a queue (implemented with std::map) for undelivered PDUs.
This queue uses the SN used for TX as the key.
- Added discard timer that is started upon reception of the SDU. Upon
expiry of the timeout a discard callback removes undelivered PDUs
from the queue.
- Added the mechanisms to the notify_delivery to remove PDUs from the
undelivered queue when the PDU is ACK'ed.
- Added test case for both timer expiry and acknowledgment.
- Fix up the getter for buffered SDUs to return the undelivered SDUs
- Changed default PDCP discard timer, so AM has a discard timer by
default.
PDCP PDUs. This includes:
- Modifying the byte_buffer_t to include PDCP SN meta-data. This way,
the RLC can keep track of the ack'ed bytes for a specific PDCP PDU.
- Added in the RLC an `undelivered_sdu_info queue`, to keep track of the
amount of ack'ed bytes and the total size of the PDCP PDU,
so the RLC can know when delivery is finished.
- Added an interface between the PDCP and the RLC so that the RLC can
notify the PDCP when it receives an ack from the status PDUs. The RLC
passes to the PDCP a vector of all the ack'ed pdus in a rx'ed status PDU.
- Added some tests to the notify functionality. This includes some tests
where the PDUs are acked imediatly, and one test where the PDU is
retx'ed.