llc_queue::{dequeue,enqueue}() refactor

As seen in OS#4420, setting the MetaInfo.recv_time outside of
llc_queue before calling llc_queue::enqueue() and later on using that
value in llc_queue itself at dequeue time is not a good idea, since it
can provoke errors if the recv_time was not set correctly.
For instance, LlcTest was not setting the value for recv_time on some
test, which ended up with a huge millisec value when substracting now()
from it:
"""
llc.cpp:215:29: runtime error: signed integer overflow: 1582738663 * 1000 cannot be represented in type 'long int'
"""
This issue only appeared when started building on a raspberrypi4.

Let's better set/store the MetaInfo.recv_time internally during
llc_queue::enqueue(). Then, enqueue() only needs the
MetaInfo.expire_time, so let's change its arg list to only receive that
to avoid confusions.

Take the chance to move the llc_queue APIs to use osmo_gettimeofday,
since we need to fake the time now that the API itself sets that time.

Also take the chance during this refactor to disallow passing null
pointer by default since no user needs that.

Finally, update the LlcTest accordingly with all API/behavior changes.

Related: OS#4420
Change-Id: Ief6b1464dc779ff22adc2b02da7a006cd772ebce
4 files changed
tree: d4b9246d93827c4d127767e328ed5396b4f2719c
  1. contrib/
  2. debian/
  3. doc/
  4. include/
  5. src/
  6. tests/
  7. .gitignore
  8. .gitreview
  9. configure.ac
  10. COPYING
  11. git-version-gen
  12. Makefile.am
  13. osmoappdesc.py
  14. README.md
  15. TODO
README.md

osmo-pcu - Osmocom Packet Control Unit

This repository contains a C/C++-language implementation of a GPRS Packet Control Unit, as specified by ETSI/3GPP. It is part of the Osmocom Open Source Mobile Communications project.

The Packet Control Unit is terminating the Layer 2 (RLC/MAC) of the GPRS radio interface and adapting it to the Gb Interface (BSSGP+NS Protocol) towards the SGSN.

The PCU interfaces with the physical layer of the radio interface. OsmoPCU is typically used co-located with the BTS, specifically OsmoBTS. For legacy BTSs that run proprietary sotware without an interface to OsmoPCU, you may also co-locate it with the BSC, specifically OsmoBSC

Homepage

The official homepage of the project is https://osmocom.org/projects/osmopcu/wiki/OsmoPCU

GIT Repository

You can clone from the official osmo-pcu.git repository using

git clone git://git.osmocom.org/osmo-pcu.git

There is a cgit interface at http://git.osmocom.org/osmo-pcu/

Documentation

We provide a user manual as well as a vty reference manual

Please note that a lot of the PCU configuration actually happens inside the BSC, which passes this configuration via A-bis OML to the BTS, which then in turn passes it via the PCU socket into OsmoPCU.

Mailing List

Discussions related to osmo-pcu are happening on the osmocom-net-gprs@lists.osmocom.org mailing list, please see https://lists.osmocom.org/mailman/listinfo/osmocom-net-gprs for subscription options and the list archive.

Please observe the Osmocom Mailing List Rules when posting.

Contributing

Our coding standards are described at https://osmocom.org/projects/cellular-infrastructure/wiki/Coding_standards

We us a gerrit based patch submission/review process for managing contributions. Please see https://osmocom.org/projects/cellular-infrastructure/wiki/Gerrit for more details

The current patch queue for osmo-pcu can be seen at https://gerrit.osmocom.org/#/q/project:osmo-pcu+status:open

Current limitations

  • No PFC support
  • No fixed allocation support (was removed from 3GPP Rel >= 5 anyway)
  • No extended dynamic allocation support
  • No unacknowledged mode operation
  • Only single slot assignment on uplink direction
  • No half-duplex class support (only semi-duplex)
  • No TA loop
  • No power loop