May 2011 - OpenBSC - lists.osmocom.org

GPRS - local and foreign TLLIs
by Luca Melette 04 Feb '26

04 Feb '26

Hello everybody, after setting up a nanoBTS with OpenBSC/SGSN/GGSN, I had some troubles trying to connect my smartphone to the GPRS cell. Investigating the BTS-to-SGSN traffic, I saw that the frames sent by the SGSN were all marked with the same N(U) value (at LLC layer), the value was 0. With some debug, I found that the there was a mismatch in the TLLI storage, used to keep the status of attached terminals. The mentioned code is contained in gprs_llc.c, involving LL Entity functions and gprs_llc_tx_ui(). /* look-up or create the LL Entity for this (TLLI, SAPI) tuple */ lle = lle_by_tlli_sapi(msgb_tlli(msg), sapi); if (!lle) { struct gprs_llc_llme *llme; LOGP(DLLC, LOGL_ERROR, "LLC TX: unknown TLLI 0x%08x, " "creating LLME on the fly\n", msgb_tlli(msg)); llme = llme_alloc(msgb_tlli(msg)); lle = &llme->lle[sapi]; } The TX function uses the previously received TLLI to lookup for the LLE. The lle_by_tlli_sapi() performs the search, but preliminary it applies a foreign2local TLLI conversion to ensure to have a local one. Since no valid entry for the searched TLLI is found, a new one is created. And the problem is here. The new entry has the foreign TLLI. Next time the lookup fails again, and a new entry is created. This way, the counter N(U) is always reset, and the mobile do not recognize the message sequence and no attach is possible. My question is about foreign and local TLLIs. I patched the lookup, avoiding the conversion, so that the LLE is found and everything works fine... but... What is the sense of the conversion? Should the TLLI be always stored as a local one? Can this problem be solved with another foreign2local while allocating new entries? Actually, my problem has been solved with that workaround. But I'm curious to know what is the right way. Hope somebody can answer :) Thanks. Cheers, LM

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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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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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sms bugfix
by Dennis Wehrle 25 Jul '11

25 Jul '11

Hello Our goal was to send status sms via the vty interface. But all of our sms were cropped. In contrast sms from one MS to another MS are displayed correctly (despite the fact, that the text at the database contains several '@' at the end / the user_data contains several zero-octets). Therefore i have inspect the code and found several bugs. The main problem is that the "user_data_len" is not correctly used. As per GSM 03.40, 9.2.3.16 TP‑User‑Data‑Length (TP‑UDL): "If the TP‑User‑Data is coded using the GSM 7 bit default alphabet, the TP‑User‑Data‑Length field gives an integer representation of the number of septets within the TP‑User‑Data field to follow." Currently the "user_data_len" contains the number of octets (returned from gsm_7bit_encode(...) at gsm_utils.c (libosmocore)). The big problem here is that this information is not unique, e.g.: 1.) 46 non-extension characters + 1 extension character => (46 * 7 bit + (1 * (2 * 7 bit))) / 8 bit = 42 octets 2.) 47 non-extension characters => (47 * 7 bit) / 8 bit = 41,125 = 42 octets 3.) 48 non-extension characters => (48 * 7 bit) / 8 bit = 42 octects But the MS has to know the correct "user_data_len" to decode the correct number of characters. For this reason i updated the gsm_7bit_encode() function to return the correct number of septets. However sometimes it is needed to know the correct number of octets (e.g. at gsm_04_11.c: gsm340_gen_tpdu(...)) => i added a function to gsm_utils.c named: uint8_t get_octet_len(const uint8_t sept_len) I have also fixed the problem, that the sms are wrongly stored / displayed on the database. But the solution on the function *sms_from_result(...) (at db.c) is not really "beautiful". This is because there exists no "user_data_len" field at the database. To store the right value for "user_data_len" (which is further needed) i have to get the length from the "text" field. Unfortunately this is not enough. If the text contains extension characters like {[]} etc. then the "user_data_len" has to be bigger because these characters needs two septets. Therefore i use a switch statement so search for these characters. A better solution for that is to store the right "user_data_len" to the database (on the encoding / decoding procedure). But i don't know if this is a suitable solution for all of you (because you have to change your database structure etc.). Best Regards Dennis Wehrle

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Licensing of the wiki
by Harald Welte 13 Jul '11

13 Jul '11

Hi all, so far we do not have any statement about the licensing of the content on our wiki. This means the default copyright rules apply: All the content is copyrighted, and nobody has any rgiht to reproduce it at all. I would like to propose an official license for the content in the wiki: Create Commons CC-BY-SA. The alternative would be to go for CC-BY-NC-SA, disallowing commercial use of the content. I'm not certain if NC is really what we want. After all, even somebody using OpenBSC in a commercial environment should be able to make copies of the reference documentation we have available - as long as he will releas the result again (which the SA part already covers). If the major contributors to the wiki would agree to a license, I would update the wiki accordingly. 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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Re: SGSN Crash
by Holger Hans Peter Freyther 10 Jun '11

10 Jun '11

On 05/30/2011 06:27 AM, Seungju Kim wrote: > Hello, I am experiencing some crash with osmo-sgsn. > This is the log : http://pastebin.com/XP8RcaaNI didnt make any modification except removing imsi roaming check. > Every time when a phone tries to connect this happens. What might be wrong? Hi, please make yourself gdb and git and create a patch. The struct msgb has detected a mis-use and forced a crash. What is going wrong is in the log, you will need to identify where this msgb got allocated (or change the panic message to print the name of the msgb) and see why it is using the amount of headroom it wants to use. happy hacking holger

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[PATCH 00/10] Control interface for OpenBSC
by Daniel Willmann 03 Jun '11

03 Jun '11

Hello, this patchset adds an SNMP-like control interface to OpenBSC. Currently you can set and get variables. This interface is enabled in osmo-bsc, osmo-bsc_nat, and in osmo-nitb. It currently supports querying the counters and rate counters, setting and querying the rf_locked status, and geographical location. In osmo-bsc_nat forwarding is implemented to set/query stuff in the actual osmo-bsc. The patches are located in the daniel/controlif branch. Please merge them if you feel they are ready or point me to the problems. Regards Daniel Willmann (10): Add documentation for the control interface protocol Add example to communicate through the control interface Add libctrl, an SNMP-like control interface libctrl: Add macros to help define commands libctrl: Add commands to query counters and rate_cntr bsc_hack: Use libctrl, listen on port 4249 osmo_bsc: Use libctrl, handle ctrl cmds on port 4249 or from the nat osmo_bsc: Add some libctrl commands libctrl: Add ctrl_cmd_cpy() to copy a command nat: Use libctrl and add command forwarding to osmo-bsc openbsc/configure.in | 1 + openbsc/contrib/bsc_control.py | 100 +++++ openbsc/doc/control-interface.txt | 21 + openbsc/include/openbsc/bsc_nat.h | 22 + openbsc/include/openbsc/control_cmd.h | 151 +++++++ openbsc/src/Makefile.am | 2 +- openbsc/src/libctrl/Makefile.am | 7 + openbsc/src/libctrl/control_cmd.c | 479 +++++++++++++++++++++++ openbsc/src/libctrl/control_if.c | 627 ++++++++++++++++++++++++++++++ openbsc/src/osmo-bsc/Makefile.am | 1 + openbsc/src/osmo-bsc/osmo_bsc_main.c | 167 ++++++++ openbsc/src/osmo-bsc/osmo_bsc_msc.c | 34 ++ openbsc/src/osmo-bsc_nat/Makefile.am | 1 + openbsc/src/osmo-bsc_nat/bsc_nat.c | 279 +++++++++++++ openbsc/src/osmo-bsc_nat/bsc_nat_utils.c | 1 + openbsc/src/osmo-nitb/Makefile.am | 3 +- openbsc/src/osmo-nitb/bsc_hack.c | 3 + 17 files changed, 1897 insertions(+), 2 deletions(-) create mode 100755 openbsc/contrib/bsc_control.py create mode 100644 openbsc/doc/control-interface.txt create mode 100644 openbsc/include/openbsc/control_cmd.h create mode 100644 openbsc/src/libctrl/Makefile.am create mode 100644 openbsc/src/libctrl/control_cmd.c create mode 100644 openbsc/src/libctrl/control_if.c -- 1.7.5.rc3

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Only nanoBTS, or any femtocell?
by Bthomas 30 May '11

30 May '11

Dear OpenBSC lovers and developers! question, I turn towards you again: if the operation OpenBSC nanoBTS and A-bis Over IP basis, you think any of the femtocell (eg Vodafone's preferred cells) are able to operate in the same way? I think that the same standard as well do they work? What is your opinion? For more information: http://wirelessfederation.com/news/74803-vodafone-hungary-launches-3ghsdpa-… Thank You, and have nice day! bthomyka from Hungary

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Re: SGSN Crash
by Sylvain Munaut 30 May '11

30 May '11

> Hello, I am experiencing some crash with osmo-sgsn. > This is the log : http://pastebin.com/XP8RcaaN > I didnt make any modification except removing imsi roaming check. > Every time when a phone tries to connect this happens. What might be wrong? Build with debug symbols so that the backtrace makes sense ... Cheers, Sylvain

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GPRS
by Seungju Kim 29 May '11

29 May '11

Hello, I am trying to make a GPRS/EDGE capable network using OpenBSC. These are my config files and results from console http://pastebin.com/rCW6cCeU But I still don't see any data indicator when I connect my iPhone to the network. What do you think is wrong? Sent from my iPhone

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