May 2015 - 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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Pysim error: SW match failed
by Martin Nagy 16 Aug '25

16 Aug '25

Hi all, After buying a super Sim Kit (16 in 1) from China, I tried the reader (green PCB inside a blue transparent plastic case with a blue LED) and SIM (identified as a fakesupersim) with pysim tool. However i am getting the following error: /pySim-prog.py -n 26C3 -c 49 -x 262 -y 42 -z 1234 -j 1 -t auto Insert card now (or CTRL-C to cancel) Autodetected card type fakemagicsim Generated card parameters : > Name : 26C3 > SMSP : e1ffffffffffffffffffffffff058100945555ffffffffffff000000 > ICCID : 8949262427518313026 > MCC/MNC : 262/42 > IMSI : 262422461512085 > Ki : 7b74741a1ee14337ec23f9ab92a13648 > OPC : ccd867d60797d8d45354a51b3ef568ff Programming ... Traceback (most recent call last): File "./pySim-prog.py", line 530, in <module> card.program(cp) File "/home/nadicek/pysim/pysim/pySim/cards.py", line 231, in program self._scc.update_binary('6f30', hplmn + 'ff' * (tl-3)) File "/home/nadicek/pysim/pysim/pySim/commands.py", line 53, in update_binary return self._tp.send_apdu_checksw(pdu) File "/home/nadicek/pysim/pysim/pySim/transport/__init__.py", line 87, in send_apdu_checksw raise RuntimeError("SW match failed ! Expected %s and got %s." % (sw.lower(), rv[1])) RuntimeError: SW match failed ! Expected 9000 and got 9804. I checked mailing lists and haven’t found anybody who had similar problem with pysim. Also I have tried forcing different models of SIM, but nothing is working. Obviously I can remove this check from the script file (__init__.py in /pySim/transport), however somebody had a reason to put such condition there. I would like to ask if it is safe to remove that line of code and the purpose of that line of code. Thanks a lot and best regards Martin

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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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[PATCH 0/4] core/conv: Fast Viterbi decoding
by Thomas Tsou 26 Apr '16

26 Apr '16

Hi all, This patch set adds to libosmocore an optimized Viterbi decodeer for architecture specific (Intel SSE) and non-specific cases. The implementation covers codes with constraint lengths of K=5 and K=7 and rates 1/4 to 3/4, which make up the majority of GSM use cases. Speedup from the current implementation is in the range of 5 to 20 depending on the processor and code type. API is unchanged. Tested on Haswell (i7-4770K) and Atom (D2550). Additional test codes from osmo-bts are included. Further tests for AWGN bit-error-rate and benchmarks can be found in the following repository. https://github.com/ttsou/osmo-conv-test Here are some examples. Bit error test for GPRS CS2 with SNR of 5 dB and 100000 bursts. $ ./conv_test -c 2 -e -r 5 -i 100000 ================================================= [+] Testing: GPRS CS2 [.] Specs: (N=2, K=5, non-recursive, flushed, not punctured) [.] Input length : ret = 290 exp = 290 -> OK [.] Output length : ret = 588 exp = 588 -> OK [.] BER tests: [..] Testing base: [..] Input BER.......................... 0.042443 [..] Output BER......................... 0.000006 [..] Output FER......................... 0.001350 (135) [..] Testing SIMD: [..] Input BER.......................... 0.042460 [..] Output BER......................... 0.000005 [..] Output FER......................... 0.001240 (124) Timed AFS benchmark with 8 threads and 100000 bursts per thread. $ ./conv_test -b -c 10 -j 8 -i 100000 ================================================= [+] Testing: GSM TCH/AFS 6.7 [.] Specs: (N=4, K=5, recursive, flushed, punctured) [.] Input length : ret = 140 exp = 140 -> OK [.] Output length : ret = 448 exp = 448 -> OK [.] Performance benchmark: [..] Encoding / Decoding 800000 bursts on 8 thread(s): [..] Testing base: [..] Elapsed time....................... 4.320001 secs [..] Rate............................... 25.925920 Mbps [..] Testing SIMD: [..] Elapsed time....................... 0.458272 secs [..] Rate............................... 244.396341 Mbps [..] Speedup............................ 9.426718 -TT

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[PATCH 2/2] libbsc: Update a BTS's SIs when ms_max_power is changed from VTY.
by Alexander Chemeris 25 Jun '15

25 Jun '15

Otherwise you have to restart BTS or at least break the RSL connection to apply the change. -- Regards, Alexander Chemeris. CEO, Fairwaves, Inc. https://fairwaves.co

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[PATCH 1/2] libbsc: Abstract out SIs update/generation for a BTS into a separate function.
by Alexander Chemeris 15 Jun '15

15 Jun '15

The code to do that doesn't belong to the control interface, so abstract it out to a separate function gsm_bts_set_system_infos(). -- Regards, Alexander Chemeris. CEO, Fairwaves, Inc. https://fairwaves.co

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[PATCH] libmsc: Improve 'max_power_red' VTY command.
by Alexander Chemeris 15 Jun '15

15 Jun '15

Changes: * Apply change even if the supplied value is odd, just warn that it is rounded. Previously the value was not set at all, which may have lead to a situation when a user thinks the BTS operating at low power, while it is running full power. * Apply change even if the supplied value is higher than the 24dB maximum suggested by the standard, just warn about this. UmSITE and probably other SDR based BTS support much wider power regulation range. * Apply change to the BTS over OML immediately. -- Regards, Alexander Chemeris. CEO, Fairwaves, Inc. https://fairwaves.co

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Why isn't ARFCN 0 supported?
by Mike McTernan (wavemobile) 08 Jun '15

08 Jun '15

Good afternoon! In libbsc/bsc_init.c we have the following case: case GSM_BAND_900: if (bts->c0->arfcn < 1 || (bts->c0->arfcn > 124 && bts->c0->arfcn < 955) || bts->c0->arfcn > 1023) { LOGP(DNM, LOGL_ERROR, "GSM900 channel must be between 1-124, 955-1023.\n"); return -EINVAL; } break; 3GPP 45.005, table 2-2 gives valid channel numbers as: P-GSM900 -> 1-124, E-GSM900 -> 0-124 and 975-1023 R-GSM900 -> 0-124 and 955-1023 ER-GSM900 -> 0-124 and 940-1023 The code looks to bounds check ARFCN closest to R-GSM900, but omits ARFCN 0. Is the check "bts->c0->arfcn < 1" erroneous, or am I missing some history? Also should it really check for the R-GSM 900 range, or should it be E-GSM (more common)? The other band checks look correct. Kind Regards, Mike PS: osmo-arfcn is okay with ARFCN 0: $ ./osmo-arfcn -a 0 ARFCN 0: Uplink 890.0 MHz / Downlink 935.0 MHz

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[PATCH] Use generic auth API
by Max 01 Jun '15

01 Jun '15

Signed-off-by: Max <max.suraev(a)fairwaves.co> --- openbsc/src/libmsc/auth.c | 69 +++++++++++++++++++---------------------------- 1 file changed, 28 insertions(+), 41 deletions(-) diff --git a/openbsc/src/libmsc/auth.c b/openbsc/src/libmsc/auth.c index 10d8edf..d04b2fc 100644 --- a/openbsc/src/libmsc/auth.c +++ b/openbsc/src/libmsc/auth.c @@ -24,47 +24,11 @@ #include <openbsc/debug.h> #include <openbsc/auth.h> #include <openbsc/gsm_data.h> - -#include <osmocom/gsm/comp128.h> +#include <osmocom/crypt/auth.h> #include <stdlib.h> -static int -_use_xor(struct gsm_auth_info *ainfo, struct gsm_auth_tuple *atuple) -{ - int i, l = ainfo->a3a8_ki_len; - - if ((l > A38_XOR_MAX_KEY_LEN) || (l < A38_XOR_MIN_KEY_LEN)) { - LOGP(DMM, LOGL_ERROR, "Invalid XOR key (len=%d) %s\n", - ainfo->a3a8_ki_len, - osmo_hexdump(ainfo->a3a8_ki, ainfo->a3a8_ki_len)); - return -1; - } - - for (i=0; i<4; i++) - atuple->sres[i] = atuple->rand[i] ^ ainfo->a3a8_ki[i]; - for (i=4; i<12; i++) - atuple->kc[i-4] = atuple->rand[i] ^ ainfo->a3a8_ki[i]; - - return 0; -} - -static int -_use_comp128_v1(struct gsm_auth_info *ainfo, struct gsm_auth_tuple *atuple) -{ - if (ainfo->a3a8_ki_len != A38_COMP128_KEY_LEN) { - LOGP(DMM, LOGL_ERROR, "Invalid COMP128v1 key (len=%d) %s\n", - ainfo->a3a8_ki_len, - osmo_hexdump(ainfo->a3a8_ki, ainfo->a3a8_ki_len)); - return -1; - } - - comp128(ainfo->a3a8_ki, atuple->rand, atuple->sres, atuple->kc); - - return 0; -} - /* Return values * -1 -> Internal error * 0 -> Not available @@ -76,6 +40,11 @@ int auth_get_tuple_for_subscr(struct gsm_auth_tuple *atuple, { struct gsm_auth_info ainfo; int i, rc; + static struct osmo_sub_auth_data auth = { + .type = OSMO_AUTH_TYPE_GSM + }; + struct osmo_auth_vector _vec; + struct osmo_auth_vector *vec = &_vec; /* Get subscriber info (if any) */ rc = db_get_authinfo_for_subscr(&ainfo, subscr); @@ -109,13 +78,23 @@ int auth_get_tuple_for_subscr(struct gsm_auth_tuple *atuple, return 0; case AUTH_ALGO_XOR: - if (_use_xor(&ainfo, atuple)) - return 0; + auth.algo = OSMO_AUTH_ALG_XOR; + if ((ainfo.a3a8_ki_len > A38_XOR_MAX_KEY_LEN) || (ainfo.a3a8_ki_len < A38_XOR_MIN_KEY_LEN)) { + LOGP(DMM, LOGL_ERROR, "Invalid XOR key (len=%d) %s\n", + ainfo.a3a8_ki_len, + osmo_hexdump(ainfo.a3a8_ki, ainfo.a3a8_ki_len)); + return -1; + } break; case AUTH_ALGO_COMP128v1: - if (_use_comp128_v1(&ainfo, atuple)) - return 0; + auth.algo = OSMO_AUTH_ALG_COMP128v1; + if (ainfo.a3a8_ki_len != A38_COMP128_KEY_LEN) { + LOGP(DMM, LOGL_ERROR, "Invalid COMP128v1 key (len=%d) %s\n", + ainfo.a3a8_ki_len, + osmo_hexdump(ainfo.a3a8_ki, ainfo.a3a8_ki_len)); + return -1; + } break; default: @@ -124,6 +103,14 @@ int auth_get_tuple_for_subscr(struct gsm_auth_tuple *atuple, return 0; } + memcpy(auth.u.gsm.ki, ainfo.a3a8_ki, sizeof(auth.u.gsm.ki)); + + if (osmo_auth_gen_vec(vec, &auth, atuple->rand) < 0) + return -1; + + memcpy(atuple->sres, vec->sres, 4); + memcpy(atuple->kc, vec->kc, 8); + db_sync_lastauthtuple_for_subscr(atuple, subscr); DEBUGP(DMM, "Need to do authentication and ciphering\n"); -- 1.9.1

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[PATCH] obscvty: Implement readlines() generator function.
by Alexander Chemeris 30 May '15

30 May '15

The function is useful to process logs generated by OpenBSC/OsmoBTS VTY. -- Regards, Alexander Chemeris. CEO, Fairwaves, Inc. https://fairwaves.co

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