OpenBSC March 2025

openbsc@lists.osmocom.org

5 participants
25 discussions

Issues with writing adoc manual for contributed library
by Mychaela Falconia 27 Jun '25

27 Jun '25

Hello Osmocom community, Over the past several months I developed my own RTP endpoint implementation library (alternative to libortp), and I seek to get it merged into libosmo-netif so it can be used by OsmoBTS as an option: https://gerrit.osmocom.org/c/libosmo-netif/+/39280 https://gerrit.osmocom.org/c/libosmo-netif/+/39281 https://gerrit.osmocom.org/c/libosmo-netif/+/39291 I am now working on documentation, which I need to finish before I can lift these patches out of WIP in Gerrit. The last of the 3 WIP patches linked above is the one adding an adoc manual, built with the same tools as other Osmocom manuals, and I need some help with this one: 1) When I run './configure --enable-manuals' followed by 'make' on the Debian machine which Vadim provided to me for Osmocom documentation work, everything seems successful and I get a PDF rendering of my WIP manual. However, as soon as I uploaded this patch to Gerrit, I see a build failure in Jenkins. What am I doing wrong? I'm afraid that my knowledge of Autotools is not good enough to figure this one out. 2) My progress in writing the actual manual has reached the point where I need to insert some graphical diagrams showing the flow of RTP packets and the latency and jitter they experience in transit. I am thinking of one horizontal axis showing regularly spaced packets as they are emitted by the source, then forward-and-down arrows showing their transit with fixed or variable latency, then another horizontal axis below showing the receiver's view of time, with marked arrival times of packets (endpoints of latency arrows) and fixed-spacing times when the GSM or TDM system polls the jitter buffer. Question: what is the appropriate tool within the accepted Osmocom adoc suite for drawing such diagrams? If I weren't trying to get my RTP implementation accepted into Osmocom, I would have written this manual in troff on my favorite 1980s UNIX system, using pic preprocessor in the troff suite for graphical drawings like this one - but I reason that I need to write my manual within Osmocom documentation framework in order to maximize the chance of the associated code library being accepted into libosmo-netif, with follow-on patches to osmo-bts to use it optionally as an alternative to libortp. 3) When I do successful test builds on Vadim's Debian machine and get a PDF rendering of my WIP manual, the cover page in the PDF features both Sysmocom and Osmocom logos just like the mainstream Osmocom manuals, with Sysmocom logo on top. While this arrangement is probably appropriate for the existing manuals which were written predominantly by members of Sysmocom crew, it seems quite wrong for an external contributor's manual that does not contain a single sentence written by Sysmocom. How do I tweak things to remove that Sysmocom logo from the cover page, or even better, put San Diego 2G Association logo in its place? My contributions to Osmocom are directly linked to my efforts to build a new GSM network in San Diego, hence there is some symmetry between Sysmocom and SD2G in terms of Osmocom FLOSS project contributions, except for the rather big asymmetry in that SD2G is strictly non-profit. M~

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dynamic traffic channels
by Neels Hofmeyr 20 May '25

20 May '25

On Tue, Jun 28, 2016 at 10:05:28AM +0200, Harald Welte wrote: > [translated from german] > is it certain that we switch a channel to PDCH only when > gprs mode != none? A TS can be GSM_PCHAN_TCH_F_PDCH; those are the only ones for which we send a PDCH ACT message. We send a PDCH ACT message - during init (CHANNEL OML's state changed to enabled -> send PDCH ACT), - and upon channel release ack when pchan == GSM_PCHAN_TCH_F_PDCH. So the question is, when we receive a channel release ack, could that be the PDCH release and we switch PDCH right back on by accident? No, because we only receive a chan rel ack when the *TCH/F* is being released. That is because the PDCH release is initiated "internally" from the PDCH DEACT, and thus this condition in common/rsl.c rsl_tx_rf_rel_ack() catches on, which existed before dyn PDCH: if (lchan->rel_act_kind != LCHAN_REL_ACT_RSL) { LOGP(DRSL, LOGL_NOTICE, "%s not sending REL ACK\n", gsm_lchan_name(lchan)); return 0; } In rsl_rx_rf_chan_rel() the rel_act_kind is set to LCHAN_REL_ACT_RSL, but not in the rsl_rx_dyn_pdch(). This is analogous to the ip.access way -- the ip.access nanobts replies to a PDCH DEACT with a PDCH DEACT ACK and doesn't send a separate channel release ack. Maybe we could set rel_act_kind to some new LCHAN_REL_ACT_IPAC_DYN_PDCH for clarity? (But we shouldn't actually send a release ack, to stay compatible.) Even though it works as-is, we should indeed add another flag check: - We do check the flags that no ACT/DEACT is already pending; - And we do send a PDCH DEACT only if ts->flags & TS_F_PDCH_ACTIVE; - But we would send a PDCH ACT despite ts->flags & TS_F_PDCH_ACTIVE. This should never happen, but it would make sense to ensure that. ~Neels

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[libosmocore] testsuite: 61 87 failed on s390x
by Jaroslav Škarvada 08 Apr '25

08 Apr '25

Hi, I built libosmocore head (commit 84dcf73625513af44e711b2c99e21ee2c33b7eff at that time) on Fedora 43 (rawhide) and on s390x 4 tests failed. Iit's s390x running in qemu on x86_64, but it also fails on native s390 - there I saw failures of tests 25 26 69 90 (unfortunately I don't have the log from the native run). So probably more tests can coredump, to see all the problematic tests, it would probably require running through the valgrind. I am reporting it according to the provided instructions thanks & regards Jaroslav

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Required support on the S3/S4 integration
by Sandip Biswas 14 Mar '25

14 Mar '25

Hi Experts, I want to integrate EPC core (Open5GS) with open-source SGSN, It would be very helpful if anyone can share any document where I can find the installation steps and all. Thanks in advance for your valuable time and consideration. Regards, Sandip Biswas ::Disclaimer:: Information contained and transmitted by this E-mail communication including any attachment is intended solely for the exclusive use of the addressee(s) and may contain information that is privileged, confidential or exempt from disclosure. Access to this e-mail and/or to the attachment by anyone else is unauthorised. If you are not the intended recipient, an agent of the intended recipient or a person responsible for delivering the information to the named recipient, you are notified that any use, distribution, transmission, printing, copying or dissemination of this information in any way or in any manner is strictly prohibited. If you are not the intended recipient of this mail kindly destroy all copies of this message and any attachments and inform the sender. ::WARNING:: Although this communication is believed to be free of any virus which might affect any computer or IT system into which they are opened, the recipient should, by all means, check this message and any attachments for the presence of any virus. The sender and sender organisation accept no liability for any damage caused or the potential thereof by any virus transmitted by this message. Thank you !

2 1

Adding doxygen style comments to header files
by Alexander 'lynxis' Couzens 05 Mar '25

05 Mar '25

Hi, it came up again in gerrit again. Currently the osmocom style states doxygen style comments should be done in the .c file. Doxygen are those comments: /*! a brief description of the function * \param something Some description of the use * \return 0 if ... */ Doxygen takes those comments and generates a html documentation of the code. I would like to change it to have those in the headers files instead (when the function in included in a header file). When using the doxygen comments only for doyxen, for sure, there isn't a difference between having it in .c or in .h files. But when using IDEs or language servers, they usually only parses headers files and the .c files of the current active project (e.g. osmo-sgsn), but not the .c files of other projects (libosmocore). On the downside I only see the problem of increasing the size of header files, but I don't see an issue in here. Any thoughts? Best, lynxis

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OpenBSC March 2025