OpenBSC February 2019

openbsc@lists.osmocom.org

15 participants
20 discussions

by mosbah abdelkader

> I don't understand. This callback will be called with data you need to write > to the network. In case of MTP Level3 you will need to wrap that around the > msgb you got. I means: is the interaction with mtp3 layer implemented (is sending sccp data by mtp3 implemented by the library?)? Also, what about the reception of data from mtp3 layer. is that implemented in the sccp lib. I am asking these questions because I see the code of mtp3 in the lib but no significant call is present in the sccp part of the lib. Thank you for your help.

1 month

dynamic traffic channels

by Neels Hofmeyr

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

2 months, 2 weeks

Google Summer of Code 2019

by Vadim Yanitskiy

Dear Osmocom community, starting from 16th of January (until 7th of February) we can apply Google Summer of Code as an Open source mentor organization. Many well-known projects, such as Debian, FFmpeg, Apache, Git, GCC, GNURadio and others, have been participating last year. Personally, I think it's a great opportunity to move some of our projects forward. I would like to know your opinions about this idea, should we participate? I would be happy to be a mentor. With best regards, Vadim Yanitskiy.

6 years, 4 months

LimeNET Micro

by Keith

The new product from Lime is marked to start shipping tomorrow. As far as I understand it is basically the LimeSDR mini with a GPS disciplined clock and a Raspberry Pi module, so it /should/ run osmo-bts + osmo-trx-lms fine, and without clocking issues. It also has POE. I was wondering if anybody else has looked at it, has comments, or has or is thinking of ordering one? Thanks!

6 years, 5 months

static strings -- little fun on the side

by Neels Hofmeyr

As a bit of relaxation in-between the serious hacking, I gave a little idea of mine a spin, which could improve our use of static string buffers. My idea is to use one common static buffer string, as a ring buffer, for all our osmo_xxx_name() functions, that returns new chunks of static string every time. Why? The point is that we have many osmo_xxx_name() functions that return a string in one single static buffer. When you call it a second time, it overwrites the buffer. So this doesn't work: printf("PLMN changed from %s to %s\n", osmo_plmn_name(old_plmn), osmo_plmn_name(new_plmn)); No matter what, this will always print the same string twice, and probably no-one would notice. For this, I have previously often invented xxx_name2() functions: printf("PLMN changed from %s to %s\n", osmo_plmn_name(old_plmn), osmo_plmn_name2(new_plmn)); With osmo_plmn_name2() being: "Same as osmo_plmn_name(), but returning in a different static buffer." That is bad for these reasons: - each new separate function adds another static buffer to the program size, which remains unused all the other time. - each new separate function adds more API signatures. Alternatively we have xxx_buf() functions, but they are more cumbersome to use: char buf[123]; gsm0808_cell_id_list_name_buf(buf, sizeof(buf), cil); LOGP(DMSC, LOGL_DEBUG, "%s\n", buf); Particularly for logging, that would always run even though the logging category might be switched off. So I came up with these patches, and changing all of current libosmocore's static buffers to using this does work: http://git.osmocom.org/libosmocore/log/?h=neels/static_strings (second last patch introduces the API, last patch changes all libosmocore callers) Also pushed to gerrit for easier review: https://gerrit.osmocom.org/13061 the benefits: - All osmo_xxx_name() functions can be called N times in a single printf() statement, without the need for managing buffers. - No osmo_xxx_name2() functions for "separate static buffer" - Just fire off LOGP() args and the code gets skipped if the category / log level is switched off: LOGP(DMSC, LOGL_DEBUG, "PLMN changed from %s to %s, but Fred says it was %s\n", osmo_plmn_name(old_plmn), osmo_plmn_name(new_plmn), osmo_plmn_name(freds_plmn)); I think it would be nice to have this mechanism for easier string hacking, but not sure if the tradeoffs / vague side effects are worth it. So this might as well remain a fun idea that never made it. Thoughts welcome. Implementation considerations... At first I thought a plain ring buffer returning the next bit of memory every time would suffice, but I didn't like the need to vaguely trust that we never use overlapping memory. The best I could come up with was to guarantee up to N subsequent static strings as non-overlapping. See the semantics around the 'recent' members. But that entails an uncomfortable tradeoff: I kind of expected to reduce the size of static char buffers in libosmocore, but if I want to disallow overlapping N uses, the buffer has to be able to hold N subsequent allocations of the largest buffer, which currently is 4100. So I end up with a larger static char buffer. The advantage however is that every libosmocore using program with its own xxx_name() functions can now use the same static string space and does not need to add more static buffers all over the place. To make the buffer smaller, I considered taking the largest buffer callers out of this, i.e. osmo_hexdump() and msgb_hexdump(). But particularly osmo_hexdump() is one of the functions that I would like to be able to call more than once in a printf() arg list. Actually that would in practice be of smaller size than the maximum 4096 currently allowed. But the 'recent' check above requires the *largest* size to fully fit N times. Consider: if I choose a total buffer of 4096 bytes and print one hexdump of 3084 bytes, then I can't print another such buffer: the osmo_static_string() function can't know that the first printf() has already concluded, and still considers that large chunk as in-use. So to be able to allow any number of subsequent printf()s of the same huge size, I need the number-of-recent-checks times that large size to fit in the static buffer. So there is a tradeoff between how many previous buffers I can guarantee to be unchanged vs. the maximum buffer size allowed per allocation. I would actually like to ensure 10 or more recent buffers, so that a caller can say: I can use up to 10 various osmo_xxx_name() functions in the same printf() statement, and libosmocore will barf if I use too much. I would also like to use less static char buffer -- but is ten times 4096 as static string buffer really a lot? Not for an x86_64 desktop machine, but what about embedded targets? Since in practice the name buffer sizes we use are more like <80 chars each, in practice we would be totally fine with one 4096 char buffer. I have never seen a hexdump of 4Kb in practice. I'm considering actually removing the 'recent' check again and just offloading the responsibilty for name buffer usage to the caller. Or I'm considering to reduce the max hexdump / msgb_hexdump size to something saner like 1024 chars or even 256 chars. (Actually, hexdump could also loop in chunks of 64 bytes or something like that). Another consideration was about how to effect bounds checking. I don't want to evaluate return values in printf() args. So I decided to provide generalized API that returns NULL pointers if the size did not fit, but for convenience use have one osmo_static_string() function that OSMO_ASSERT()s as soon as the size doesn't fit, instead. ~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

6 years, 5 months

Osmocom-Debian-install-test fails for 10 consecutive days!

by Harald Welte

Dear Osmocom community, for the last 10 days our "Debian installation test" job is consistently failing, see https://jenkins.osmocom.org/jenkins/job/Osmocom-Debian-install-latest/ It somehow seems to be related to soapySDR mismatching versions where we use a 0.5 package from the debian feed: > Get:358 http://deb.debian.org/debian stretch/main amd64 libsoapysdr0.5-2 amd64 0.5.4-1 [64.4 kB] and mix that with a 0.7 lms7 module from our feed: > Get:425 http://download.opensuse.org/repositories/network:/osmocom:/latest/Debian_9… ./ soapysdr0.7-module-lms7 19.01.0-1 [49.9 kB] > Unpacking soapysdr0.7-module-lms7:amd64 (19.01.0-1) ... > dpkg: error processing archive /tmp/apt-dpkg-install-aYn9qf/398-soapysdr0.7-module-lms7_19.01.0-1_amd64.deb (--unpack): > trying to overwrite '/usr/lib/x86_64-linux-gnu/SoapySDR/modules0.5-2/libLMS7Support.so', which is also in package ... > Errors were encountered while processing: /tmp/apt-dpkg-install-aYn9qf/398-soapysdr0.7-module-lms7_19.01.0-1_amd64.deb > E: Sub-process /usr/bin/dpkg returned an error code (1) > Build step 'Execute shell' marked build as failure > Finished: FAILURE Does anyone know of any change that would have triggered this? I've created https://osmocom.org/issues/3809 to track this. Regards, Harald -- - Harald Welte <hwelte(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

6 years, 5 months

fsm: Delaying dispatch of events while we're already inside a dispatch callback.

by Sylvain Munaut

Hi, Currently if you call osmo_fsm_dispatch from a function that happens to have been triggered by another call to dispatch, things can get a little bit messy (depending on where that callback is in the chain of even that may/may not change the state of the FSM). So what I would propose is that any event dispatched to an FSM will be processed only after the processing of any previous event is fully completed (in the order they were generated). I have a prototype implementation for review on gerrit : https://gerrit.osmocom.org/c/libosmocore/+/12983 Now, this does break some tests, but looking at the breakage, it looks just like message re-ordering at first glance. I guess running the whole full range of test on this would be useful. There are also another consequence is that it's now impossible to return an error code if that event can't be handled in the current state (previously dispatch would return -1). But since the actual dispatch can be deferred ... well, can't do much. Looking at the codebase, that error code is ignored most of the time. When it's returned, it seems to always end up being ignored at the end of the chain (because well ... realistically there isn't much you can do about it anyway, it's a programming bug if it happens). Thoughts / Comments ? Useful ? Crazy idea ? ... Cheers, Sylvain

6 years, 5 months

less osmo-msc patches

by Neels Hofmeyr

Hi everyone, let me remind you that I am refactoring the RAN connection in osmo-msc to allow for inter-MSC handover. Patches merged to osmo-msc now are almost guaranteed to produce merge conflicts. Cosmetic changes to RAN code are likely to be obsolete. I would prefer if you guys wouldn't bother for another few weeks. Thanks, ~N

6 years, 5 months

Build failed in Jenkins: Coverity-Upload (jenkins-job-builder) #395

by jenkins＠lists.osmocom.org

See <https://jenkins.osmocom.org/jenkins/job/osmocom-coverity/395/display/redire…> ------------------------------------------ Started by timer Building remotely on build2-deb9build-ansible (ttcn3 osmo-gsm-tester-build osmocom-gerrit-debian9 osmocom-master-debian9 coverity) in workspace <https://jenkins.osmocom.org/jenkins/job/osmocom-coverity/ws/> Wiping out workspace first. Cloning the remote Git repository Cloning repository git://git.osmocom.org/osmo-ci > git init <https://jenkins.osmocom.org/jenkins/job/osmocom-coverity/ws/> # timeout=10 ERROR: Error cloning remote repo 'origin' hudson.plugins.git.GitException: Could not init <https://jenkins.osmocom.org/jenkins/job/osmocom-coverity/ws/> at org.jenkinsci.plugins.gitclient.CliGitAPIImpl$5.execute(CliGitAPIImpl.java:772) at org.jenkinsci.plugins.gitclient.CliGitAPIImpl$2.execute(CliGitAPIImpl.java:564) at org.jenkinsci.plugins.gitclient.RemoteGitImpl$CommandInvocationHandler$1.call(RemoteGitImpl.java:153) at org.jenkinsci.plugins.gitclient.RemoteGitImpl$CommandInvocationHandler$1.call(RemoteGitImpl.java:146) at hudson.remoting.UserRequest.perform(UserRequest.java:212) at hudson.remoting.UserRequest.perform(UserRequest.java:54) at hudson.remoting.Request$2.run(Request.java:369) at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Suppressed: hudson.remoting.Channel$CallSiteStackTrace: Remote call to build2-deb9build-ansible at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1741) at hudson.remoting.UserRequest$ExceptionResponse.retrieve(UserRequest.java:357) at hudson.remoting.Channel.call(Channel.java:955) at org.jenkinsci.plugins.gitclient.RemoteGitImpl$CommandInvocationHandler.execute(RemoteGitImpl.java:146) at sun.reflect.GeneratedMethodAccessor338.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.jenkinsci.plugins.gitclient.RemoteGitImpl$CommandInvocationHandler.invoke(RemoteGitImpl.java:132) at com.sun.proxy.$Proxy87.execute(Unknown Source) at hudson.plugins.git.GitSCM.retrieveChanges(GitSCM.java:1146) at hudson.plugins.git.GitSCM.checkout(GitSCM.java:1186) at hudson.scm.SCM.checkout(SCM.java:504) at hudson.model.AbstractProject.checkout(AbstractProject.java:1208) at hudson.model.AbstractBuild$AbstractBuildExecution.defaultCheckout(AbstractBuild.java:574) at jenkins.scm.SCMCheckoutStrategy.checkout(SCMCheckoutStrategy.java:86) at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:499) at hudson.model.Run.execute(Run.java:1810) at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43) at hudson.model.ResourceController.execute(ResourceController.java:97) at hudson.model.Executor.run(Executor.java:429) Caused by: hudson.plugins.git.GitException: Command "git init <https://jenkins.osmocom.org/jenkins/job/osmocom-coverity/ws/"> returned status code 1: stdout: stderr: <https://jenkins.osmocom.org/jenkins/job/osmocom-coverity/ws/.git>: No space left on device at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandIn(CliGitAPIImpl.java:1996) at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandIn(CliGitAPIImpl.java:1964) at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandIn(CliGitAPIImpl.java:1960) at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommand(CliGitAPIImpl.java:1597) at org.jenkinsci.plugins.gitclient.CliGitAPIImpl$5.execute(CliGitAPIImpl.java:770) ... 11 more ERROR: Error cloning remote repo 'origin'

6 years, 5 months

OML bringup bugs and compatibility

by Harald Welte

Dear Osmocom community, It has recently been uncovered that there are some problems in the OML bringup sequence between OsmoBSC and OsmoBTS. Basically, the core of the issue circulates around the RADIO CARRIER managed object. * OsmoBTS is accepting OPSTART even though no attributes (such as ARFCN) are set * OsmoBSC is sending OPSTART twice for this MO, while it's only sending it once for all other MOs The problem now is: If we "fix" the BTS side to reject the OPSTART without prior SET RADIO CARRIER ATTRIBUTES, then older OsmoBSC will stop to work with newer OsmoBTS. The underlying issue is that if we OPSTART the transceiver before setting the ARFCN, then the later setting of attributes is no longer going to do anything, as the radio has already started with "ARFCN 0". TS 12.21 is not very clear on *when* attributes are permitted to be set. The MO can be either locked or unlocked, or it can be enabled or not... My idea so far was that if you want to change attributes of a MO (such as the ARFCN), you need to first bring it down somehow (e.g. set it to "locked"), then make the change and finally bring it online again. A bit of playing with a nanoBTS revealed that it actually permits the OPSTART not only before the attributes are set, but also before the software has even been activated for that MO. This makes no sense whatsoever, though. More details in: https://osmocom.org/issues/3789 and https://osmocom.org/issues/3782, particularly the last few updates to those tickets. Any ideas? -- - 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)

6 years, 5 months

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OpenBSC February 2019