OpenBSC June 2022

openbsc@lists.osmocom.org

13 participants
18 discussions

MSC, SIP connector, and Asterisk
by James Connor 11 Jul '22

11 Jul '22

Hey all, I've got a bit of an interesting use case. I've been working to setup the OpenBSC components in order to simulate stress testing a GSM network. I've been able to get communications across the GSM working properly, with MSs able to place calls. However, part of what I'm trying to do involves routing to a simulated PSTN. I turned to sip-connector and asterisk, but my network immediately stopped working once I told the MSC to use an external MNCC. The setup involves two separate computers. The first is the BSS, which has a BSC, MGW, virtual BTS, and two MSs running on mobile and virtphy. The second is the NSS, with the MSC/VLR, HLR, MGW, and STP. The GSM is split between the two devices because of the eventual goal to increase the number of BSSs to better simulate a real-world GSM. This was all working fine, until I modified osmo-msc.cfg to include "mncc external /tmp/msc_mncc". In parallel, I setup osmo-sip-connector and ran it on the NSS through the same "/tmp/msc_mncc" socket, pointing it at Asterisk (also on the NSS). This was all done according to the instructions listed here: https://osmocom.org/projects/osmo-sip-conector/wiki/Howto. Now whenever I place my calls (which I do through mobile's "call" VTY command on the BSS), the call doesn't connect and simply gets released after 30 seconds. After doing some debugging, I've determined that Asterisk is not receiving anything from the sip-connector. Meanwhile, the sip-connector is being told to delete any connection basically as soon as it's created: <0001> mncc.c:1005 MNCC rcvd message type: MNCC_SETUP_IND <0001> mncc.c:566 Created call(5004) with MNCC leg(2147483652) IMSI(001010000000001) <0001> mncc.c:68 Starting Timer for MNCC_RTP_CREATE <0001> mncc.c:164 MNCC sent message type: MNCC_RTP_CREATE <0001> mncc.c:1005 MNCC rcvd message type: MNCC_REL_IND <0001> mncc.c:636 Rcvd MNCC_REL_IND, Cause: RESOURCE_UNAVAIL <0001> mncc.c:648 leg(2147483652) was released. <0002> call.c:90 call(5004) released. The MSC has the following as part of its output when a call is placed: ... <0020> osmo_ss7.c:1933 0: asp-OsmoMSC-asp: xua_cli_read_cb(): sctp_recvmsg() returned 48 (flags=0x80) <0023> m3ua.c:714 0: asp-OsmoMSC-asp: Received M3UA Message (XFER:DATA) <0023> m3ua.c:543 0: asp-OsmoMSC-asp: m3ua_rx_xfer <0023> m3ua.c:566 0: asp-OsmoMSC-asp: m3ua_rx_xfer(): M3UA data header: opc=2233=1.23.1 dpc=185=0.23.1 <0020> osmo_ss7_hmrt.c:276 m3ua_hmdc_rx_from_l2(): found dpc=185=0.23.1 as local <0020> sccp_scrc.c:472 scrc_rx_mtp_xfer_ind_xua: HDR=(CO:CODT,V=0,LEN=0), PART(T=Destination Reference,L=4,D=00000007), PART(T=Segmentation,L=4,D=00000000), PART(T=Data,L=6,D=000422040120) <0021> sccp_scoc.c:1664 Received CO:CODT for local reference 7 <0021> sccp_scoc.c:1698 SCCP-SCOC(7)[0x555adb5ddf40]{ACTIVE}: Received Event RCOC-DT1.ind <0021> sccp_user.c:175 Delivering N-DATA.indication to SCCP User 'OsmoMSC-A' <0011> sccp_ran.c:108 (GERAN-A-7) sccp_ran_sap_up(N-DATA.indication) <0003> ran_peer.c:591 ran_peer(GERAN-A:RI-SSN_PC:PC-1-23-1:SSN-BSSAP)[0x555adb5b1010]{READY}: Received Event RAN_PEER_EV_MSG_UP_CO <0007> ran_peer.c:407 msc_i(IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ)[0x555adb5d97e0]{READY}: Received Event MSC_EV_FROM_RAN_UP_L2 <0011> ran_msg_a.c:790 msc_i(IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ)[0x555adb5d97e0]{READY}: RAN decode: BSSMAP: CLEAR REQUEST <0007> msc_i.c:85 msc_a(IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ)[0x555adb5daa50]{MSC_A_ST_COMMUNICATING}: Received Event MSC_A_EV_FROM_I_PROCESS_ACCESS_SIGNALLING_REQUEST <000b> msc_a.c:196 msc_a(IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ)[0x555adb5daa50]{MSC_A_ST_COMMUNICATING}: + msc_a_ran_dec: now used by 2 (cc,msc_a_ran_dec) <0011> ran_msg_a.c:790 msc_a(IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ)[0x555adb5daa50]{MSC_A_ST_COMMUNICATING}: RAN decode: BSSMAP: CLEAR REQUEST <0011> msc_a.c:1612 msc_a(IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ)[0x555adb5daa50]{MSC_A_ST_COMMUNICATING}: RAN decode: BSSMAP Clear Request <0007> msc_a.c:1433 msc_a(IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ)[0x555adb5daa50]{MSC_A_ST_COMMUNICATING}: Received Event MSC_A_EV_MO_CLOSE <0007> msc_a.c:733 msc_a(IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ)[0x555adb5daa50]{MSC_A_ST_COMMUNICATING}: State change to MSC_A_ST_RELEASING (X2, 30s) <0011> msc_a.c:769 msc_a(IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ)[0x555adb5daa50]{MSC_A_ST_RELEASING}: Releasing: msc_a use is 2 (cc,msc_a_ran_dec) <000b> msc_a.c:773 VLR subscr IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97 + msc_a_fsm_releasing_onenter: now used by 4 (attached,active-conn,CC,msc_a_fsm_releasing_onenter) <000b> vlr.c:309 VLR subscr IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97 + vlr_subscr_cancel_attach_fsm: now used by 5 (attached,active-conn,CC,msc_a_fsm_releasing_onenter,vlr_subscr_cancel_attach_fsm) <000b> vlr.c:314 VLR subscr IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97 - vlr_subscr_cancel_attach_fsm: now used by 4 (attached,active-conn,CC,msc_a_fsm_releasing_onenter) <0001> transaction.c:230 trans(CC:INITIATED IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ callref-0x80000003 tid-8) Freeing transaction <0005> gsm_04_08_cc.c:237 trans(CC:INITIATED IMSI-001010000000001:MSISDN-1234567891:TMSI-0x9B96EF97:GERAN-A-7:CM_SERVICE_REQ callref-0x80000003 tid-8) tx MNCC_REL_IND ... Any thoughts as to why this one change to my GSM is suddenly stopping it from functioning properly? Thanks, any help is greatly appreciated! - James P.S. I didn't want to include my config files for fear of making this message absurdly long, but let me know if you want to see any and I'll gladly post them.

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Using a mixture of authentication-required and unauthenticated IMSIs
by Mychaela Falconia 01 Jul '22

01 Jul '22

Hello Osmocom community, A question: is it possible to configure OsmoMSC+OsmoHLR such that authentication is required for those IMSIs for which key material records are present in HLR subscriber db, yet allow unauthenticated access for certain other IMSIs (specific ones, *not* accept-all) that are entered into HLR subscriber db without keys? My use case: I generally operate my network with SIMs of my own issue, and I wish to continue enforcing authentication (and using ciphering) for all Themyscira SIMs. However, I would like to play with some old phone models which cannot be found unlocked - only operator-locked units can be found on ebay - and some of those historical operator- locked phones come with SIM cards in them, issued by historical operators who have bit the dust ages ago. It would be really nice if I could add the IMSIs of those defunct-operator SIMs to my HLR subscriber db and allow them to connect - which would have to be unauthenticated, as I don't know their Ki or even their A38 algorithm version - but do so _without_ dropping the authentication requirement for my own Themyscira IMSIs. Is what I seek possible with current OsmoMSC and OsmoHLR? And if it isn't possible with current code, any ideas as to what would be the right way to implement such a feature? TIA, Mychaela

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RFC: Reviving OsmoDevCall
by Harald Welte 28 Jun '22

28 Jun '22

[please follow-up-to openbsc(a)lists.osmocom.org so we don't cross-post all related mails] Dear Osmocom community, OsmoDevCall used to be rather successful for quite some time in recent years, but recently has been suffering quite a bit due to insufficient people volunteering to present. Big thanks to all who did! Interestingly, there's no shortage of ideas of topics at https://osmocom.org/projects/osmo-dev-con/wiki/OsmoDevCall - but then many of the potential speakers did not have the interest or time to follow-up. Most recently, the last few instances have not been taking place due to a lack of volunteers during my holidays. Last, but not least, while during COVID lockdown winter "friday night 8pm" was a good idea, this of course is more difficult during the summer, when people are more likely want to go out the weekend. So, to summarize, let me ask some questions: * would you be interested in OsmoDevCall continuing? * which day/time/timezone would you prefer ? * would you be able and willing to volunteer to give at talk within the next 3 or so months? Any other suggestions for or around OsmoDevCall are of course also welcome. Thanks in advance, 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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dazed and confused.
by Keith 27 Jun '22

27 Jun '22

Often I struggle to understand memory allocations and the "weird" things of C, so please point out to me what I'm missing here (I must be wrong, because you guys would not miss this, right? cleared_ci = (struct osmo_mgcpc_ep_ci){ .ep = ep, .mgcp_client_fi = ci->mgcp_client_fi, .got_port_info = ci->got_port_info, .rtp_info = ci->rtp_info, .occupied = true, /* .pending = true follows below */ .verb = verb, .notify = { .fi = notify, .success = event_success, .failure = event_failure, .data = notify_data, } }; osmo_strlcpy(cleared_ci.label, ci->label, sizeof(cleared_ci.label)); osmo_strlcpy(cleared_ci.mgcp_ci_str, ci->mgcp_ci_str, sizeof(cleared_ci.mgcp_ci_str)); *ci = cleared_ci; LOG_CI_VERB(ci, LOGL_DEBUG, "notify=%s\n", osmo_fsm_inst_name(ci->notify.fi)); #define LOG_CI_VERB(ci, level, fmt, args...) do { \ if (ci->verb_info.addr[0]) \ LOG_CI(ci, level, "%s %s:%u: " fmt, \ osmo_mgcp_verb_name(ci->verb), ci->verb_info.addr, ci->verb_info.port, \ ## args); \ else \ LOG_CI(ci, level, "%s: " fmt, \ osmo_mgcp_verb_name(ci->verb), \ ## args); \ } while(0) How is ci->verb_info not being using uninitialized here? Would that explain random crashes with this code? https://osmocom.org/issues/5572

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Contract / Support
by jeff palmer 17 Jun '22

17 Jun '22

Hi, I am looking for contracted support on a osmocom based project, for a few days of configuration/setup assistance on a 2G / GPRS configuration. There are a lot of moving parts in the osmocom projects and versions of individual projects. Best to grab an expert on the subject than for us to dive in quite so deep just to work through some configurations. Please email me with contact details and will reach out immediately! Jeffery Palmer GSE

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call between different MSCs
by a.r.nasab＠chmail.ir 13 Jun '22

13 Jun '22

Hi I'm going to establish a call between two MSes on two different MSCs . Is This Scenario possible without an external application (for MNCC interface)? Are there any options other than LCR(Linux Call Router)? Best Regards

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Request - USIM/ISIM JavaCard Repo Access
by Jeremy Solmonson 07 Jun '22

07 Jun '22

Hi Osmocom Team, Long time listener, first time writer. Short Version: Would it be possible to get the source for your USIM/ISIM JavaCard applets that are installed on the sysmoISIM-SJA2, please? The Alternative: I've been researching a method to give my JavaCard applet default installation, and if my applet doesn't support the ADPU command, then it will revert back to your USIM/ISIM applet. Unfortunately, I have not found a solution. If you know of one, this would solve my ADPU update problem. Long Version: I've been looking into how SmartCards work and got interested in SIM card pertaining to JavaCard applets. I am interested in creating my own ADPU commands while still supporting all other ADPU commands that USIM/ISIM provide. Given the awesomeness of your products and dedication to open source research, I was hoping you can help me by providing the source. This way, I can overwrite the USIM/ISIM applets on the sysmoISIM-SJA2, and support my new ADPU updates. BTW, I looked/searched for these in your github repos and could not find these applets. Let me know if this is possible. Thanks for being awesome! -- Jeremy S.

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Using Osmocom CNI to operate a "real" cellphone network
by Mychaela Falconia 07 Jun '22

07 Jun '22

Hello Osmocom community, Is there anyone here who uses Osmocom CNI software to operate a "real" cellular phone network (2G or 3G or both) anywhere in USA, or am I going to be the first? By "real", I mean operating a cellular phone network that strives to provide a user experience to its subscribers that is as close as possible to what one would get from a "regular" operator like AT&T or T-Mobile, aside from much much smaller coverage area, perhaps as small as the operator's house and its immediate surroundings. But aside from the tiny coverage area, all other aspects of user experience need to be fully "real": each subscriber gets a real 10-digit phone number in the North American Numbering Plan, can receive calls and SMS at this number, and can place calls and send SMS to the outside world, with the user's real NANP number appearing as the source. The principal difference from a self-contained classic NITB setup is that subscribers' MSISDNs are real NANP, rather than made-up "extension" numbers, plus a PSTN gateway implementation for outside connectivity. Is there anyone in USA (or anywhere else in the world, substituting your country's "real" numbering plan for NANP) who operates an Osmocom CNI network in this manner? If there isn't, I will be happy to be the first, and I will also be quite happy to publish the source for all of the custom sw components I'm going to develop for this task - which I plan to implement as add-ons to Osmocom CNI, connecting via MNCC, SMPP and GSUP interfaces, rather than patches to Osmocom sw components themselves. However, if I am not the first to embark on such a venture, it would be nice to know how others have done it before me, so I can make a more informed decision as to what I can reuse vs which wheels I would rather reinvent per my own taste. Someone please correct me if I'm wrong, but it is my understanding that Rhizomatica (the most "real" and "production" user of Osmocom CNI I know of) does things differently from what I envision: aside from being in Mexico rather than USA (hence no NANP), it is my understanding (again, someone please correct me if I'm wrong) that they don't give their individual subscribers (end users) direct phone numbers in the Mexican numbering plan, directly reachable from anywhere in the world as +52-xxxxx, instead subscribers get "extension" numbers that are meaningful only inside those special village networks. In other words, a PBX-style network like the inside of a company with phone extensions, rather than direct PSTN phone numbers. I currently plan on using bulkvs.com as my North American PSTN connectivity back-end provider with real NANP phone numbers, at least for voice - I haven't found a solution for P2P SMS connectivity yet, but because of the complexity of the task, I decided to break it into pieces and focus on just voice at first. However, if someone else has already done something similar, operating your own cellular network where your subscribers get real 10-digit NANP phone numbers instead of just internal extensions, I would be interested in knowing whom you use (or used) as your back-end provider for PSTN connectivity and source of phone numbers, and if anyone was able to get P2P SMS included in the deal. M~

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OpenBSC June 2022