OpenBSC August 2017

openbsc@lists.osmocom.org

19 participants
43 discussions

OpenBSC USSD external application
by Rowan Phipps 16 Sep '17

16 Sep '17

Hi, I’ve been looking into getting ussd working with an external application. I found a branch from last year (fairwaves/sup-ussd) that looks like it has implemented most of ussd sessions and possibly communicates with an external application. Does anyone know if it was finished or what still needs to be done? I also found a python script called ussd_example.py which looks like it is supposed to act as a gateway and receive used connections from openbsc. Is this correct and did it work or am I misunderstanding its purpose? Thanks! - Rowan Phipps

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catch-22 VTY error
by Neels Hofmeyr 08 Sep '17

08 Sep '17

I'd like to share a VTY config error analysis that has a tricky solution: I started osmo-bsc -c osmo-bsc.cfg with, according to openbsc/doc/examples/osmo-bsc: net [...] bts 0 [...] periodic location update 30 trx 0 [...] and get this error: There is no such command. Error occurred during reading below line: trx 0 what? 'net / bts / trx' is no command?? Solution: I'm on the vlr_3G branch (incorporating 2G via A-interface) and on this branch, I've actually moved the 'periodic location update N' command a level up, from net / bts / periodic to net / periodic (background: assuming that OsmoMSC does not have individual BTS info, we moved some settings up to network level; whether this makes sense for osmo-bsc is a different question, it's just what happens to be on the vlr_3G branch now). So there is no net / bts / periodic command. Why do I get an error for net / bts / trx instead? two reasons: 1. 'trx 0' was the line following the 'periodic' command, 2. since 'periodic' exists one level above, the vty code goes to the parent node automatically. About 2: we tend to indent our VTY config files, but in fact the indentation has no effect whatsoever, it is just eye candy (very useful eye candy). The code in question: If a command does not exist, try 'vty_go_parent()' and see if the command exists there. That's what allows us to omit 'exit' in our config files to go to the parent node explicitly: libosmocore/src/vty/command.c: int config_from_file(struct vty *vty, FILE * fp) { int ret; vector vline; while (fgets(vty->buf, VTY_BUFSIZ, fp)) { vline = cmd_make_strvec(vty->buf); /* In case of comment line */ if (vline == NULL) continue; /* Execute configuration command : this is strict match */ ret = cmd_execute_command_strict(vline, vty, NULL); /* Try again with setting node to CONFIG_NODE */ while (ret != CMD_SUCCESS && ret != CMD_WARNING && ret != CMD_ERR_NOTHING_TODO && is_config_child(vty)) { HERE -----> vty_go_parent(vty); ret = cmd_execute_command_strict(vline, vty, NULL); } cmd_free_strvec(vline); if (ret != CMD_SUCCESS && ret != CMD_WARNING && ret != CMD_ERR_NOTHING_TODO) return ret; } return CMD_SUCCESS; } In this case the 'periodic...' command does in fact now exist one level above, so the vty_go_parent() is successful and running that command works. But, the vty config parsing then sits above on the 'network' level, is no longer in 'bts 0' and hence refuses to accept the following bts-level command, in this case 'trx 0'. Confusing! So it's not a bug, it's a feature. But it's a feature we might see quite often if we move the 'periodic' command up to network level and users attempt to use their old config files. Same goes for the 'timezone' command, BTW, so we might want to rename commands, or re-consider moving commands one level up in the first place. Maybe we should leave backward compat catchers in place that print a warning. ~N -- - Neels Hofmeyr <nhofmeyr(a)sysmocom.de> http://www.sysmocom.de/ ======================================================================= * sysmocom - systems for mobile communications GmbH * Alt-Moabit 93 * 10559 Berlin, Germany * Sitz / Registered office: Berlin, HRB 134158 B * Geschäftsführer / Managing Directors: Harald Welte

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jenkins build slaves: Rationale for some builds in docker vs. some not?
by Harald Welte 06 Sep '17

06 Sep '17

Hi! We have some builds that happen inside a docker, and some that happen natively on the (Debian 8) build slave. Can somebody involved with this illustrate why that is the case, and what's the rationale here? Just looking at the setup, I'm unable to figure out whether there's any particular reason for this, or whether it's simply "we started without and then did some builds in docker but nobody migrated the other builds over" >From my point of view, I would have assumed that building in different containers would make sense to e.g. build on different distributions / versions, or building against older libosmo* vs. building against libosmo* from nightly package feeds vs. re-building all dependencies from master. But it appears that only a single container is built, and that container is used for some jobs (like osmo-msc-gerrit) but not for other jobs. If I missed some wiki page or mailing list posts with related information, a pointer would be helpful. Thanks in advance. Regards, Harald -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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about merging deletion of checking-value-strings script from libosmocore
by Neels Hofmeyr 02 Sep '17

02 Sep '17

I would have welcomed more patience in merging https://gerrit.osmocom.org/3685, "Use value string check from osmo-ci" in libosmocore. (the commit log of which fails to indicate removal of the script, btw) Moving to the new repositories, I have enough loose ends flapping in the wind, and dropping the script from libosmocore has added yet another distraction, while not being necessary to start using the one from osmo-ci. Max clearly posted "N. B: this should be merged last, after all the repos converted to check script from osmo-ci." -- which is not the case for the new repositores split from openbsc.git. In osmo-msc I have >50 patches waiting to be merged. The timing could hardly have been worse, luckily only a few gerrit builds are affected. Will try to sort out merging of the patches without needing a rebase and >50 rebuilds. Thanks for you attention :) ~N

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RFC: use git-version-gen from gnulib
by Max 02 Sep '17

02 Sep '17

Hi. I'd like to propose to switch from local (unmaintained?) copy of git-version-gen script and use it directly from upstream gnulib package. It's available pretty-much everywhere (including ancient Debian which we support for nightly). It's also available in meta-oe: https://layers.openembedded.org/layerindex/recipe/47365/ It doesn't feel right to use copy-pasted code when we could offload the maintenance work to packaging/dependency tools. What do you think? Please contribute to https://osmocom.org/issues/2467 which I've created to track this RFC. -- Max Suraev <msuraev(a)sysmocom.de> http://www.sysmocom.de/ ======================================================================= * sysmocom - systems for mobile communications GmbH * Alt-Moabit 93 * 10559 Berlin, Germany * Sitz / Registered office: Berlin, HRB 134158 B * Geschaeftsfuehrer / Managing Director: Harald Welte

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[PATCH] test/common.sh: fix typo in gapk binary location
by Vadim Yanitskiy 31 Aug '17

31 Aug '17

--- test/common.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/test/common.sh b/test/common.sh index 39cdd7d..591be3a 100644 --- a/test/common.sh +++ b/test/common.sh @@ -4,7 +4,7 @@ REFDIR=./ref-files if [ -f ../src/gapk ]; then GAPK=../src/gapk elif [ -f `which gapk` ]; then - GAPK=`whiich gapk` + GAPK=`which gapk` else exit 1 fi -- 2.14.1

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redmine e-mails broken from 08/26 through 08/31
by Harald Welte 31 Aug '17

31 Aug '17

Dear Osmocom community, from August 26th 06:54 UTC through August 31st 06:22 UTC our Osmocom.org redmine could not send any e-mails. This was due to a configuration file syntax error introduced by me, my apologies. If you rely on redmine e-mail notifications to the issues you have subscribed to, please double-check as related notifications during that interval were unfortunately lost. Best regards, Harald p.s.: The reason for the config change was to enable e-mail notifications from jenkins.osmocom.org (which it now has, if you want to configure e.g. post-build notification actions). -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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Wanted: OpenBSC / Osmocom users in Pakistan?
by Harald Welte 31 Aug '17

31 Aug '17

Hi All! I'm wondering if there are any users of the Osmocom cellular stack in Pakistan around. If so, please kindly follow-up by private mail, as there might be some projects in which your help would be appreciated. Thanks in advance. Regards, Harald -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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BSC+BTS SI + LAPD validation, TTCN-3 Testsuite
by Harald Welte 29 Aug '17

29 Aug '17

Dear all, I've started to implement some test cases that validate the accuracy of OsmoBTS and OsmoBSC SYSTEM INFORMATION generation. Those test cases are written in TTCN-3, which is a special programming language specifically designed for testing and validation of protocol stacks. For those present at OsmoDevCon, I've briefly presented about it there. In terms of general core infrastructure, I've written: * Definition of GSM RR and some other commonly used GSM types using the TTCN-3 type description language and the TITAN RAW (binary) encoder/decoder. The beauty of this is that one can simply describe the message structure without having to generate any code for encoding/decoding the message. See http://git.osmocom.org/osmo-ttcn3-hacks/tree/library/GSM_Types.ttcn and http://git.osmocom.org/osmo-ttcn3-hacks/tree/library/GSM_SystemInformation.… * A GSMTAP Test Port, whcih is basically how a TTCN-3 testcase/testsuite interacts with a given IUT (implementation under test). It is implemented as dual-faced port on top of the TITAN IPL4asp (ip layer 4) port and implements GSMTAP header encoding/decoding from/to TTCN-3 structured data types: http://git.osmocom.org/osmo-ttcn3-hacks/tree/library/GSMTAP_PortType.ttcn which uses http://git.osmocom.org/osmo-ttcn3-hacks/tree/library/GSMTAP_Types.ttcn describing the GSMTAP header format. * Helper functions to emulate interactive use of the VTY based on the existing TITAN TELNETasp Test Port: http://git.osmocom.org/osmo-ttcn3-hacks/tree/library/Osmocom_VTY_Functions.… * L1CTL type definition (again using auto-generated encoder/decoders!) http://git.osmocom.org/osmo-ttcn3-hacks/tree/library/L1CTL_Types.ttcn as well as an L1CTL Test Port at http://git.osmocom.org/osmo-ttcn3-hacks/tree/library/L1CTL_PortType.ttcn Using the above one can easily interface from TTCN3 with L1CTL of virtphy in order to e.g. sync to a BTS on a given ARFCN and establish a dedicated radio channel. Here is where the beautoy of the TTCN3 type language, templates and matching can be seen. It's very easy to perform something like "does this IMMEDIATE ASSIGNMENT match the RA + FN of the RACH request that I sent? Based on all of the above, there's two test suites: == Test Suites 1) SYSTEM INFORMATION contents and scheduling validation I've written some SI validation code which can be found at http://git.osmocom.org/osmo-ttcn3-hacks/tree/sysinfo SI scheduling is quite complex, particularly when you have many of the 2ter/2bis/2quater/13/2n/... enabled. At some point actually you will overflow what's possible to comply with the rules in a BCCH Norm. and you have to go to a BCCH Extd. (OsmoBTS doesn't implement the latter yet, btw). See e.g. function f_validate_si_scheduling() for validation of scheduling constraints: http://git.osmocom.org/osmo-ttcn3-hacks/tree/sysinfo/Test.ttcn#n229 Later in the file you can find test cases TC_cellid() and below for the individual test cases that validate that individual VTY configured values such as BSIC, CellId, LAC, ... are actually broadcast in the SI message. IT will update its internal matching template and then perform a sequence of VTY commands to e.g. change the LAC followed by verifying that the LAC of the decoded SI has actually changed. The above tools have helped to discover (and fix) the following bugs: * http://osmocom.org/issues/2368 * http://osmocom.org/issues/2367 * http://osmocom.org/issues/2365 (very critical, I believe) and also the not-yet-fixed but low-importance * http://osmocom.org/issues/2364 2) LAPDm testing I've written some (early) LAPDm testing code at http://git.osmocom.org/osmo-ttcn3-hacks/tree/lapdm The idea here is to test for valid and invalid transactions on the Um interface and see how OsmoBTS and the libosmcore lapdm code perform. With very few lines, this has already uncovered the following issues: * http://osmocom.org/issues/2370 * http://osmocom.org/issues/2380 Unfortunately my progress was severely affected over the weekend as I spent about one working day wrapping my head around something that turned out to be a bug in the Eclipse TITAN RAW coder, see https://www.eclipse.org/forums/index.php/t/1087557/ - fortuantely the Titan team has provided both a work-around and a fix today, which I count as excellent service. If you're curious about TTCN-3, I strongly recommend http://www.ttcn-3.org/files/TTCN3_P.pdf as an introductory slide deck. == Outlook I want to add more test cases to the sysinfo and lapdm test suites and get hands-on experience with the Junit XML output plugin. At that point, a Debian 9 build slave of our jenkins should be able to automatically build + run the latest test cases from osmo-ttcn3-hacks.git and present the individual test case results inside jenkins. I also want to add test suites for validation of: * proper generation + scheduling of of PAGING REQUEST in the BTS, considering paging groups particularly in the context of different BS_AG_BLKS_RES values * CBCH validation * proper generation of CCCH load indications by the BTS, i.e. generate a certian load e.g. on uplink RACH and check the reports * TA loop verification (add timing information to GSMTAP and then dynamically change timing from MS side to see that BTS is compensating as expected * power control loop verification: GSMTAP already has a field for transmitting RSSI in dBm. We can adjust this from the MS side to validate the BTS will adjus the instructed transmit power level of the virtual MS accordingly * actually exhaust all channels of a multi-TRX virtual BTS in different channel combinations, verify we can establish all existing logical channels in each configuration * combine the last topic with configurations that have dynamic PDCH/TCH channels to verify we properly switch forward and backward * various link failure conditions, i.e. does the BTS close the logical channel in the expected timing after uplink loss? Despite my current excitement about all of this, I'm not sure how much time I will be able to spend on this, given that the sysmocom customer priority is typically not the development of automatic test suites. But I'll try my best. If anyone wants to join: TITAN is just one "apt-get install eclipse-titan" away! == What's not good to test with TTCN-3 / TITAN: While the existing infrastructure I've built is very suitable to test low-level protocol topics, I think it's not particularly useful/applicable in other areas: * SI REST OCTETS and GPRS RLC/MAC, as they're defined in CSN.1 and TITAN has no CSN.1 encoder/decoder. For easy mathing/generation of those messages, we'd have to find something like an external CSN.1-to-ASN.1-BER or CSN.1-to-XML converter which we could use. I'd be happy to consider paying a reasonable amount for a proprietary product, just as long as we are sure that it will provde the kind of productivity that's useful here. * full end-to-end tests with actual mobile phones, RF and BTSs in the picture. We already have osmo-gsm-tester for this, and Titan with its powerful type language, templates and matching capabilities doesn't provide all that much benefit here over other languages/approaches * higher-layer protocol testing. We do have OsmocomBB as a L2 + L3 MS-side implementation, and I don't think it makes sense to replicate this. Even while the message encoding/decoding is super easy with TITAN, we still have all the related state machines. So I'd rather extend OsmocomBB where needed for automatic test cases than reinvent the wheel here. Regards, Harald -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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Osmocom release process update
by Max 28 Aug '17

28 Aug '17

Hi. Just a heads-up on recent changes related to Osmocom releases. In short: read about it at https://osmocom.org/projects/cellular-infrastructure/wiki/Make_a_new_release Somewhat longer explanation: In attempt to simplify and structure release process (see https://projects.osmocom.org/issues/1861 ) I've added helper script (osmo-release.mk, installed by recent libosmocore-dev) which attempts to automate as much as possible: * treat library and non-library projects differently * autogenerate debian/changelog * automatically bump version * cleanup TODO-RELEASE * checks for missing *_LIBVERSION update * automatically commit, sign and tag the result Of course it might fail to do the right thing for multitude of reasons (incorrectly filled TODO-RELEASE, missing tags, missing git-version-gen helper, weird versions in debian/changelog etc) so nothing is pushed automatically. You're expected to inspect the release commit and push it manually (don't forget to push the tag too!). In general, it works: made libosmo-abis 0.4.0 and osmo-bts 0.6.0 releases using it. The patches to make it available to other *osmo* projects are under review. Now, if you've read that far, you must be really interested in making release for some Osmocom project (or just really bored :) Either way, please do any of the following: * read the wiki page linked above and see if anything unclear/poorly written/needs corrections * suggest further updates to release policy described in there * review corresponding patches in gerrit * suggest further automation step (ideally, as a patch to osmo-release.mk ;) * try "make release" for one of the projects not mentioned above (if you have sufficient rights to push tags to gerrit) * have a look at recent libosmo-abis (>=0.4.0) and osmo-bts (>=0.6.0) and see if anything is broken N. B: release helper expects version to follow http://semver.org/ - this has been raised in ML and no objections followed. Please adhere to it for all future versions. -- Max Suraev <msuraev(a)sysmocom.de> http://www.sysmocom.de/ ======================================================================= * sysmocom - systems for mobile communications GmbH * Alt-Moabit 93 * 10559 Berlin, Germany * Sitz / Registered office: Berlin, HRB 134158 B * Geschaeftsfuehrer / Managing Director: Harald Welte

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OpenBSC August 2017