OpenBSC July 2011

openbsc@lists.osmocom.org

22 participants
33 discussions

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 08 Jul '25

08 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.

4 3

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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GSM @ Camp 2011 preparations
by Harald Welte 02 Aug '11

02 Aug '11

Hi Peter and others, it seems like the situation regarding the GSM network at the Camp is starting to become clearer every day. I am still arguing that two relatively large BTS with circular antennas are a good idea. Therefore, I have now applied for a test license with the regulatory authority with the following parameters: * six GSM 1800 ARFCN * two antennas, circular, 18 meters above ground * 5W output power on each ARFCN. I know one of my customers in Germany has once managed to get a license for 5W, so I thought it is a good bet we should get the same. It should be more than sufficient to cover the camp. * from August 2nd through August 15th, i.e. we have time for build-up and can also run it one more day during shutdown of the camp I should be receiving "Motorola Horizon Macro" BTSs with 3 to 6 TRX each soon. They are able to drive something like >= 20W output power, way more than we need. The only problem with those BTS is: We will need to add the Motorola A-bis dialect to OpenBSC before the Camp, which could be a tough task depending on how far they are off the standard A-bis as specified in 08.58 and 12.21. If we cannot make those BTS work, our options are somewhat limited. 1) nanoBTS based The nanoBTS are 200mW only, so we would need a booster. Those cost about 1000 EUR for 6W downlink power + 18dB uplink LNA. Who is going to fund that? Also, we would need a combiner/splitter to run something like a 3-TRX setup. 2) Ericsson RBS I should have two RBS 2308 (4TRX each) soon, but both of them are GSM 1900. It is unlikely that we ge a license, and a lot of phones probably don't support it. So unless they can somehow be converted to 1800 MHz units, they are not a good fit either :/ 3) Siemens BS-11 All of them are GSM 900. No way to get a license in Germany, sorry. So we basically _have to_ make the Motorola Horizon work... 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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AW: Current OpenBSC + LCR using MNCC socket
by Andreas.Eversberg 01 Aug '11

01 Aug '11

> I've committed some changes a couple of minutes ago (to libosmocore + > openbsc) that make lcr compile again. > The problem is: The query is always false, so no messages are sent to OpenBSC. > If I comment out the if-query, everything works as expected: Calls can be made mobile originated and mobile terminated. > However, I don't think the if-query is there without a reason. Since there is only one (gsm-)network instance, the "gsm->network" pointer must be set to something != NULL. Then it should work Thanx, applied both fixes. (blindly) Please try if it works.

5 11

Camp preparation and pySim
by Holger Hans Peter Freyther 30 Jul '11

30 Jul '11

Hi Sylvain, do we need such a hack on top of the 27c3 branch for the upcoming camp? I will try to create a proper patch before the start of the camp. holger

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nanoBTS + external Antennas + Repeater
by Lennart Müller 27 Jul '11

27 Jul '11

Good morning, I would like to use two directional antennas with a nanoBTS DCS1800. As far as I know, first I need a duplexer to use one antenna both for RX and TX - does anybody know a cheap model? I found only one for 500 Euros. Second, to connect two antennas to the duplexer, I need a power splitter. Can somebody suggest one for duplex usage? Third, to improve indoor signal level, there are plenty offers of duplex repeaters, but the legal situation is unclear because one might produce distortion on ARFCNs different from his own. Again, anyone with experience? Maybe a suggestion for a model with a fixed ARFCN setting? Thanks, Lennart

2 1

sms bugfix
by Dennis Wehrle 26 Jul '11

26 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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[PATCH] sms: Kill the text field, fix the size and truncation
by Holger Hans Peter Freyther 25 Jul '11

25 Jul '11

Patches from Dennis Wehrle, fix the truncation of SMS from the VTY --- openbsc/src/libmsc/db.c | 34 +++++++++++++++------------------- openbsc/src/libmsc/gsm_04_11.c | 2 +- openbsc/src/libmsc/gsm_04_80.c | 4 +++- 3 files changed, 19 insertions(+), 21 deletions(-) diff --git a/openbsc/src/libmsc/db.c b/openbsc/src/libmsc/db.c index 53675f7..d1dd749 100644 --- a/openbsc/src/libmsc/db.c +++ b/openbsc/src/libmsc/db.c @@ -51,7 +51,7 @@ static char *create_stmts[] = { "INSERT OR IGNORE INTO Meta " "(key, value) " "VALUES " - "('revision', '2')", + "('revision', '3')", "CREATE TABLE IF NOT EXISTS Subscriber (" "id INTEGER PRIMARY KEY AUTOINCREMENT, " "created TIMESTAMP NOT NULL, " @@ -108,9 +108,7 @@ static char *create_stmts[] = { "ud_hdr_ind INTEGER NOT NULL, " "dest_addr TEXT, " "user_data BLOB, " /* TP-UD */ - /* additional data, interpreted from SMS */ - "header BLOB, " /* UD Header */ - "text TEXT " /* decoded UD after UDH */ + "ud_length INTEGER NOT NULL " ")", "CREATE TABLE IF NOT EXISTS VLR (" "id INTEGER PRIMARY KEY AUTOINCREMENT, " @@ -177,7 +175,7 @@ static int check_db_revision(void) return -EINVAL; } rev = dbi_result_get_string(result, "value"); - if (!rev || atoi(rev) != 2) { + if (!rev || atoi(rev) != 3) { dbi_result_free(result); return -EINVAL; } @@ -990,15 +988,16 @@ int db_subscriber_assoc_imei(struct gsm_subscriber *subscriber, char imei[GSM_IM int db_sms_store(struct gsm_sms *sms) { dbi_result result; - char *q_text, *q_daddr; + char *q_daddr; unsigned char *q_udata; char *validity_timestamp = "2222-2-2"; + uint8_t octet_len = 0; /* FIXME: generate validity timestamp based on validity_minutes */ - dbi_conn_quote_string_copy(conn, (char *)sms->text, &q_text); dbi_conn_quote_string_copy(conn, (char *)sms->dest_addr, &q_daddr); - dbi_conn_quote_binary_copy(conn, sms->user_data, sms->user_data_len, + octet_len = gsm_get_octet_len(sms->user_data_len); + dbi_conn_quote_binary_copy(conn, sms->user_data, octet_len, &q_udata); /* FIXME: correct validity period */ result = dbi_conn_queryf(conn, @@ -1006,15 +1005,14 @@ int db_sms_store(struct gsm_sms *sms) "(created, sender_id, receiver_id, valid_until, " "reply_path_req, status_rep_req, protocol_id, " "data_coding_scheme, ud_hdr_ind, dest_addr, " - "user_data, text) VALUES " + "user_data, ud_length) VALUES " "(datetime('now'), %llu, %llu, %u, " - "%u, %u, %u, %u, %u, %s, %s, %s)", + "%u, %u, %u, %u, %u, %s, %s, %u)", sms->sender->id, sms->receiver ? sms->receiver->id : 0, validity_timestamp, sms->reply_path_req, sms->status_rep_req, sms->protocol_id, sms->data_coding_scheme, sms->ud_hdr_ind, - q_daddr, q_udata, q_text); - free(q_text); + q_daddr, q_udata, sms->user_data_len); free(q_daddr); free(q_udata); @@ -1029,8 +1027,9 @@ static struct gsm_sms *sms_from_result(struct gsm_network *net, dbi_result resul { struct gsm_sms *sms = sms_alloc(); long long unsigned int sender_id, receiver_id; - const char *text, *daddr; + const char *daddr; const unsigned char *user_data; + int octet_len; if (!sms) return NULL; @@ -1059,17 +1058,14 @@ static struct gsm_sms *sms_from_result(struct gsm_network *net, dbi_result resul sms->dest_addr[sizeof(sms->dest_addr)-1] = '\0'; } - sms->user_data_len = dbi_result_get_field_length(result, "user_data"); + sms->user_data_len = dbi_result_get_uint(result, "ud_length"); user_data = dbi_result_get_binary(result, "user_data"); + if (sms->user_data_len > sizeof(sms->user_data)) sms->user_data_len = (uint8_t) sizeof(sms->user_data); + octet_len = gsm_get_octet_len(sms->user_data_len); memcpy(sms->user_data, user_data, sms->user_data_len); - text = dbi_result_get_string(result, "text"); - if (text) { - strncpy(sms->text, text, sizeof(sms->text)); - sms->text[sizeof(sms->text)-1] = '\0'; - } return sms; } diff --git a/openbsc/src/libmsc/gsm_04_11.c b/openbsc/src/libmsc/gsm_04_11.c index ee7f577..ad3b300 100644 --- a/openbsc/src/libmsc/gsm_04_11.c +++ b/openbsc/src/libmsc/gsm_04_11.c @@ -628,7 +628,7 @@ static int gsm340_rx_tpdu(struct gsm_subscriber_connection *conn, struct msgb *m switch (sms_alphabet) { case DCS_7BIT_DEFAULT: - gsm_7bit_decode(gsms->text, smsp, gsms->user_data_len); + gsm_7bit_decode_hdr(gsms->text, smsp, gsms->user_data_len, gsms->ud_hdr_ind); break; case DCS_8BIT_DATA: case DCS_UCS2: diff --git a/openbsc/src/libmsc/gsm_04_80.c b/openbsc/src/libmsc/gsm_04_80.c index 39738a5..c7dad43 100644 --- a/openbsc/src/libmsc/gsm_04_80.c +++ b/openbsc/src/libmsc/gsm_04_80.c @@ -68,12 +68,14 @@ int gsm0480_send_ussd_response(struct gsm_subscriber_connection *conn, struct msgb *msg = gsm48_msgb_alloc(); struct gsm48_hdr *gh; uint8_t *ptr8; + uint8_t octet_len; int response_len; /* First put the payload text into the message */ ptr8 = msgb_put(msg, 0); response_len = gsm_7bit_encode(ptr8, response_text); - msgb_put(msg, response_len); + octet_len = gsm_get_octet_len(response_len); + msgb_put(msg, octet_len); /* Then wrap it as an Octet String */ msgb_wrap_with_TL(msg, ASN1_OCTET_STRING_TAG); -- 1.7.4.1 --------------090106040904000308080203--

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Fwd: Radios
by Barnaby Astles 25 Jul '11

25 Jul '11

Forgot the list >.< Barnaby J Astles ---------- Forwarded message ---------- From: Barnaby Astles <bjastles(a)gmail.com> Date: Sun, Jul 24, 2011 at 11:16 Subject: Re: Radios To: Harald Welte <laforge(a)gnumonks.org> Yes Think you are right ... I am just horrified at the cost of the ip.access. I would like to get in to the project but the cost of entry is just so enormous. All I can do is research and hope to land on some sort of deal. Then I would try to get a low powered temp licence and the make the case for a low powered non-interference license to Industry Canada to deploy low cost building/campus zones. I am kind of sick to see all the spectrum get eaten up by the large corps and leave nothing for small companies. Barnaby J Astles On Sun, Jul 24, 2011 at 02:52, Harald Welte <laforge(a)gnumonks.org> wrote: > Hi Barnaby, > > On Sat, Jul 23, 2011 at 01:15:49PM -0400, Barnaby Astles wrote: > > Has any one looked at airspan radios ? > > I am not aware of anyone in our community having had access to those > devices. > > > http://www.airspan.com/products/airharmony/ > > it's hard to judge how easily they would integrate with OpenBSC based on > the marketing speech says ;) > > I would guess that it should be fairly simple to integrate the GSM part, > if it reuses the Abis related components from ip.access. > > However, they could just use some completely different parts of the > ip.access software stack, and have something custom over the back-haul > link. > > If you have an interest in OpenBSC interoperability with those units, > I'm sure we could find a way to make it happen. My guess is that > they would be pretty expensive, as the nanoBTS alone (without any LTE) > is already horribly expensive. > > 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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OpenBSC July 2011