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.
- multiple tunnels per E-RAB
- data forwarding between connected GTPU tunnels
- forwarding GTPU End Marker between connected tunnels
- TeNB GTPU handles in-sequence delivery when multiple tunnels for the same ERAB exist.
this patch refactors the SDU queuing and dropping policy of the RLC and PDCP layer.
the previous design had issues when packets have been generated at a higher
rate above the PDCP than they could be consumed below the RLC.
When the RLC SDU queues were full, we allowed two policies, one to block on the write
and the other to drop the SDU. Both options are not ideal because they either
lead to a blocking stack thread or to lost PDCP PDUs.
To avoid this, this patch makes the following changes:
* PDCP monitors RLC's SDU queue and drops packets on its north-bound SAP if queues are full
* a new method sdu_queue_is_full() has been added to the RLC interface for PDCP
* remove blocking write from pdcp and rlc write_sdu() interface
* all writes into queues need to be non-blocking
* if Tx queues are overflowing, SDUs are dropped above PDCP, not RLC
* log warning if RLC still needs to drop SDUs
* this case should be avoided with the monitoring mechanism
this is an extension to the currently available security
configuration and activation methods provided by PDCP.
The new call allows to specify a Rx and Tx SN after which the
entire security config, i.e. integrity and ciphering, should
be enabled.
this is mainly required for the PDCP entity of the conformance
testing SS but could potentially also be used by the eNB
to enable security for PDCP after sending the SecModeCommand
for example.
the extra call was added to not break the existing API.
previously PDCP security (integrity and ciphering) could only
be enabled for both Rx and Tx at the same time.
this, however, caused an issue during the conformance testing in which,
in TC_8_2_1_1() for example, the eNB sends a SecModeCommand and a
RRC Reconfiguration in the same MAC TB. In this case, the eNB
needs to be able to enable DL security right after sending the SecModeCmd
in order to send the RRCReconfig encrypted. However, enabling UL security needs
to be postponed until after the SecModeComplete is received.
This patch allows to enable PDCP security for rx/tx independently if
that is needed. The default way is like before, enabling it for tx/rx at
the same time.
there were two defaults and one was shadowing the other. This
commit removes both defaults and uses blocking-mode for RRC
calls to PDCP in the UE. The eNB write_sdu() uses the non-blocking
mode by default. We have to review the eNB's RRC perhaps and use blocking
there too and non-blocking only for data plane
this fixes the issue when the stack is torn down if, for example,
the radio couldn't be loaded correctly. it will hence call stop() on all stack
components which are not initialzized yet, and logging therefore doesn't work.
the log object is know during contruction time and therefore can be passed
in as soon as possible.
Pedro Alvarez
faluco
Francisco
Andre Puschmann
Francisco Paisana
Xavier Arteaga
Ismael Gomez
David Rupprecht
yagoda