OpenBSC April 2012

openbsc@lists.osmocom.org

12 participants
18 discussions

Re: Help with sccp library
by mosbah abdelkader 07 Jul '25

07 Jul '25

> 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.

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SimpleHLR: A web interface for OpenBSC
by Peter Caprioli 03 Jun '13

03 Jun '13

Hello everyone, I've just finnished writing together a small web interface for the OpenBSC HLR. It allows you to modify various parameters in the database and also provides a set of functions to modify the HLR or sending SMSes in your own scripts. The project is still very alpha but it seems to work reasonably good. Feel free to give any feedback! Screenshots and source code is available on my website: https://stormhub.org/simplehlr/ -- *Best regards, Peter Caprioli*

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Several questions
by jason mercury 06 Dec '12

06 Dec '12

I have some questions: 1) When I start bsc_hack bsc_init.c first establishes OML link and initializes the bts then it establishes RSL link and bts starts broadcasting. However, it takes so much time to start the bts. Instead of this I want to do the following: it establishes OML link at the beginning and only once, then when i want to start broadcasting it establishes just the RSL link and bts will start faster since i don't have to wait for OML link. What should be done for this? 2) If i send one or two word messages from telnet interface it is okay. But if i send a longer message the phone could't receive the end of the message correctly(last words may be incomplete). Did any one encounter with this problem? What is wrong with me? 3) Could I send SMS in which extension of the sender is text not integer. For example, i want to send an information SMS that this is a test network. For this purpose i want to send an SMS from 'OpenBSC'. I set the extension of the first subscriber in database as text and tried to send the SMS but SMS wasn't delivered. What should i do? 4) Can i add SMS externally to SMS table of database? Thanks. Jason

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Possible solution to ticket #55
by Frank Maas 07 May '12

07 May '12

As reported in ticket #55 SGSN can crash due to double free-ing. You can replace 'can' by 'will' in that last phrase. I had a sift through the code and tried to solve this by removing the free in gprs_ns.c. Whenever the calling function created the msgb-struct, I have made the function free it after its use. If the function got the msgb from a calling function, there will not be a free (hoping that will be done on the higher level). HTH/F

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Sagem OT-290 trace phone / GSMTAP integration
by Harald Welte 07 May '12

07 May '12

Hi all! Thanks to a generous donor, we have received a couple of OT-290 trace phones. These are commercial products intended for taking L2/L3 air interface traces. If you've read any of the fabulous GSM papers by Prof. Dr.-Ing. Joachim Goeller: The OT-phones is what he used to generate all his traces. The majority of what those phones can do is now also possible with OsmocomBB. However, OT-290 support GPRS tracing/testing - for CS-1 throguh CS-4. I would be willing to give away one of the two remaining OT-290 (for free) to anyone who would in return commit to developing a GSMTAP interface for it. The message format on the serial UART between phone and PC is documented (PDF documentation by Sagem included with the phones). So based on this documentation and an OT-290 phone, it should be possible to write a small command-line program that receives the GSM/GPRS messages from the OT-290 and sends them via GSMTAP into wireshark. The result would then be similar to what http://cgit.osmocom.org/cgit/dct3-gsmtap/ is for DCT-3 phones. If you're interested, please respond to this message. Please don't apply for the phone if you are not able to find the required time and interest for actually doing the GSMTAP integration. Thanks! -- - 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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Re: gprs_llc.c: foreign TLLI is stored, but not searched
by VID - Frank Maas 30 Apr '12

30 Apr '12

Holger wrote: > wanted to avoid this issue is that whoever transmits needs to select the > llme/lle. I think my code set old_tlli to the foreign or such but I dropped it > (and can't remember why it wasn't needed anymore). Been there, tried that. It wasn't so much that is wasn't needed, but elsewhere in the code old_tlli (and especially the fact if it is 0xffffffff or not) is used to (re)set some stuff. > This will not be the last issue you will experience with GPRS. Both the > nanoBTSs implementation and our SGSN are not very stable. Well... only 7 hours of Qday to go ;-) > Some of the known GPRS issues include: > > - http://openbsc.osmocom.org/trac/ticket/55 (crash) I solved that one > - http://openbsc.osmocom.org/trac/ticket/44 (correctness) > - http://openbsc.osmocom.org/trac/ticket/43 (leak) Will check these. > There is also the 'santos' branch of someone that forked our code and has > done a bit of bugfixing. Ah ok. I'll look into that. Might be of use during the last couple of hours HTH/F

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gprs_llc.c: foreign TLLI is stored, but not searched
by Frank Maas 30 Apr '12

30 Apr '12

I might be horribly wrong, but there is something I did not grasp in gprs_llc.c. So I altered it, but since I am not sure I share it here... Function 'gprs_llc_tx_ui' uses function 'lle_by_tlli_sapi' to retrieve an lle based on a tlli/sapi combination. To do the lookup, the supplied tlli is 'localized' (tlli_foreign2local). If this does not result in a succesful find, function 'llme_alloc' is used to "create an LLME on the fly". However 'llme_alloc' does not localize the tlli. So every next search for the lle fails. For this I created this patch: --- openbsc/openbsc/src/gprs/gprs_llc.c 2012-04-30 15:42:58.958823325 +0200 +++ ../openbsc/openbsc/openbsc/src/gprs/gprs_llc.c 2012-04-30 10:54:11.291836887 +0200 @@ -157,7 +160,8 @@ if (!llme) return NULL; - llme->tlli = tlli; + llme->tlli = tlli_foreign2local(tlli); llme->old_tlli = 0xffffffff; llme->state = GPRS_LLMS_UNASSIGNED; This seems to have solved the problem (unable to get an IP link operational), but I am not sure if this was the correct way to handle this, so please feel free to comment. HTH/F

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[SHOWCASE] OpenBSC used during Queensday (NL)
by VID - Frank Maas 30 Apr '12

30 Apr '12

Goodafternoon, This is just a quick email to let you know that we are currently (as in: today) using OpenBSC to offer a GPRS service to some equipment during Queensday. For those of you that do not know this: Queensday is a Dutch festivity where the birthday of the Queen is celebrated. It attracts a mass of people and under that condition no (normal) mobile network will stay operational. Since we have some equipment running, we decided to try out creating our own mobile network. For this we installed several ip.access nanoBTSes and use OpenBSC as central software. Unfortunately this is not a complete success. Although we tested it and those tests gave us confidence, we now experience a lot of connection losses. Several nanoBTS'es bootstrap quite regularly, and almost all connected devices are unreachable after several minutes (some later than others). Only restarting OmniBSC quite often seems to bring back some life. Up until now I have been unable to find out why things are wrong. While preparing for this use of OpenBSC I came accross some things that might be worthwhile to share with you. I'll do that in separate messages, so contents does not get clobbered. Please allow me to thank you all for the great work you have done in this set of software. I hope some of my experiences will help you pushing this forward. Kind regards, Frank

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OpenBSC (GPRS) on VMWare/ESXi 4: UDP problem
by VID - Frank Maas 30 Apr '12

30 Apr '12

Please be aware of a problem in ESXi in which the checksum of UDP packets is wrongly calculated. This will cause the UDP traffic from the SGSN to the BTS'es (vice versa) to fail. It can take quite a while to figure this out (well... to be honest all it takes is a good look at the extended tcpdump output, but hey). If you experience problems setting up GPRS (symptom: NSVC remains ALIVE BLOCKED), try this command: ethtool --offload eth0 rx off tx off gso off (with eth0 the correct interface, or better: for all interfaces). This works under CentOS (tested) and Debian/Ubuntu (read about it). HTH/F

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LAPDm / RSL EST IND
by Harald Welte 29 Apr '12

29 Apr '12

Hi jolly, I'm seeing some strange behavior on the BTS side LAPDm code: When we get a SABM on SAPI=3 from the phone, this gets translated into an RSL_RLL_EST_IND. However, as there commonly is no l3 payload in a SAPI=3 SABM, the L3_INFO IE should not be present in that message. Instead of a RLL_EST_IND without L3_INFO IE, we get a L3_INFO IE that consists only of 1 byte tag and 2 byte length, but not payload. The Length value seems non-deterministic, i.e. like uninitialized memory. I've tried to resolve this, and I suspect it is somehow related to the DUMMY msgb that the lapd code allocates (why is it doing that?) in send_dl_simple(). The code path should be: lapd_rx_u() if (length == 0) send_dl_simple() send_rslms_dlsap() here we check for (!dp->oph.msg), but since there is a dummy msgb, we probably run into the send_rslms_rll_l3() case instead of send_rll_simple(). What do you think is the best way to resolve this? Thanks, 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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OpenBSC April 2012