OpenBSC January 2018

openbsc@lists.osmocom.org

29 participants
47 discussions

by mosbah abdelkader

> 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.

1 month

dynamic traffic channels

by Neels Hofmeyr

On Tue, Jun 28, 2016 at 10:05:28AM +0200, Harald Welte wrote: > [translated from german] > is it certain that we switch a channel to PDCH only when > gprs mode != none? A TS can be GSM_PCHAN_TCH_F_PDCH; those are the only ones for which we send a PDCH ACT message. We send a PDCH ACT message - during init (CHANNEL OML's state changed to enabled -> send PDCH ACT), - and upon channel release ack when pchan == GSM_PCHAN_TCH_F_PDCH. So the question is, when we receive a channel release ack, could that be the PDCH release and we switch PDCH right back on by accident? No, because we only receive a chan rel ack when the *TCH/F* is being released. That is because the PDCH release is initiated "internally" from the PDCH DEACT, and thus this condition in common/rsl.c rsl_tx_rf_rel_ack() catches on, which existed before dyn PDCH: if (lchan->rel_act_kind != LCHAN_REL_ACT_RSL) { LOGP(DRSL, LOGL_NOTICE, "%s not sending REL ACK\n", gsm_lchan_name(lchan)); return 0; } In rsl_rx_rf_chan_rel() the rel_act_kind is set to LCHAN_REL_ACT_RSL, but not in the rsl_rx_dyn_pdch(). This is analogous to the ip.access way -- the ip.access nanobts replies to a PDCH DEACT with a PDCH DEACT ACK and doesn't send a separate channel release ack. Maybe we could set rel_act_kind to some new LCHAN_REL_ACT_IPAC_DYN_PDCH for clarity? (But we shouldn't actually send a release ack, to stay compatible.) Even though it works as-is, we should indeed add another flag check: - We do check the flags that no ACT/DEACT is already pending; - And we do send a PDCH DEACT only if ts->flags & TS_F_PDCH_ACTIVE; - But we would send a PDCH ACT despite ts->flags & TS_F_PDCH_ACTIVE. This should never happen, but it would make sense to ensure that. ~Neels

1 month

GSM 04.08 L2 pseudo length in ACCH System Information messages

by Vadim Yanitskiy

Hi everyone, I few days ago, during some usual R&D process, I noticed the following messages, appearing in the log output of OsmocomBB/mobile application: "ACCH message type 0xXX unknown." The network, a phone was connected to, was may own and based on more or less recent versions of OsmoNiTB, OsmoBTS, and OsmoTRX. Despite I used to see such messages before, I didn't pay too much attention. But this time I've decided to figure out, what's wrong there... The source of such messages is the gsm48_rr.c / gsm48_rr_rx_acch(): static int gsm48_rr_rx_acch(struct osmocom_ms *ms, struct msgb *msg) { // ... struct gsm48_system_information_type_header *sih = msgb_l3(msg); // ... switch (sih->system_information) { case GSM48_MT_RR_SYSINFO_5: return gsm48_rr_rx_sysinfo5(ms, msg); case GSM48_MT_RR_SYSINFO_5bis: return gsm48_rr_rx_sysinfo5bis(ms, msg); case GSM48_MT_RR_SYSINFO_5ter: return gsm48_rr_rx_sysinfo5ter(ms, msg); case GSM48_MT_RR_SYSINFO_6: return gsm48_rr_rx_sysinfo6(ms, msg); default: LOGP(DRR, LOGL_NOTICE, "ACCH message type 0x%02x unknown.\n", sih->system_information); return -EINVAL; } } To get I bit more details, I modified this function to print the whole L3 payload, and got some interesting results. As it turned out, the payloads were shifted one byte left - there was no 'l2_plen', which is assumed by: /* Section 9.1.3x System information Type header */ struct gsm48_system_information_type_header { uint8_t l2_plen; uint8_t rr_protocol_discriminator :4, skip_indicator:4; uint8_t system_information; } __attribute__ ((packed)); So, my first idea was that this is a bug of OsmocomBB, that would be fairly easy to fix, so after a quick look at the GSM 04.08 specification I wrote (and merged :/) this: https://gerrit.osmocom.org/#/c/5204/ And everything was great, until I connected a 'patched' mobile to a commercial mobile network... And all SI messages during a dedicated connection were false-identified as SI5ter. This seemed strange to me, so I decided to compare a SI message from commercial network with a message captured in my own one: https://habrastorage.org/webt/t8/zs/vv/t8zsvvjjglzfisnjqlnnsy4kgas.png And this confused me even more, then I've expected. Why there is 0x49? Wireshark false-identified this message as something related to SMS... What if this is exactly the 'l2_plen' assumed in OsmocomBB before? I looked at the specifications again, and found out that initially I refered an outdated 5.3.0 version, which was the first link in Google: http://www.etsi.org/deliver/etsi_gts/04/0408/05.03.00_60/gsmts_0408v050300p… while the latest one is 7.21.0: http://www.etsi.org/deliver/etsi_ts/100900_100999/100940/07.21.00_60/ts_100… So, I compared the 9.1.37-40 sections of both versions, and bingo! In the higher version ACCH System Information messages do have the 'L2 Pseudo Length' (10.5.2.19) field. Finally, what I've learned: - OsmocomBB / mobile follows the new version here (with l2_plen); - OsmoNiTB generates the ACCH SI messages without the l2_plen; - Recent Wireshark versions fail to decode the ACCH SI messages with l2_plen, while older ones are able to do that; - I should not merge the changes so quick. My questions are: - Which way of composing the SI messages is correct? - If both are correct, how to parse them correctly? - Should we change OsmoNiTB / OsmoBSC to follow the latest specs? And of course, I have to revert the change I've merged. With best regards, Vadim Yanitskiy.

7 years, 3 months

Submissions for OsmoDevCon 2018

by Harald Welte

Dear Osmocom community, it's already end of January and OsmoDevCon 2018 in April is getting closer and closer. As indicated before, I would like to group the topics by days and put together at least a rough framework shcedule, so that people with specific interests don't have to be present for four full days to make sure they don't miss anything. So I'd like to re-invite all attendees to consider adding a topic/porposal to the wiki page at https://osmocom.org/projects/osmo-dev-con/wiki/OsmoDevCon2018#section-9 so that we can group different topic areas and put together a rough schedule outline. A proposal doesn't mean you have to give a talk. It could be anything, including * a talk that you would want to listen to, and you're looking for somebody to give it * a discussion about a certain topic * a workshop / hands on session * lightning talks? Like any community event, OsmoDevCon lives by its contributors. I can't wait to hear about all the things you've been up to. Thanks! 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)

7 years, 3 months

Approach to system testing for Osmocom stack

by Holger Freyther

Hi, the lua binding code was added to be able to automate OpenBSC tests. In theory we should be able to do this for SMS and UpdateLocation (call handling with MNCC exposing is left as a todo) but in practice we miss a piece of software to coordinate this and run the test. We miss it because it is an interesting problem but also I lost time on switching countries, learning new tricks at a project... The basic testing structure looks easy as well. We want to define the number of concurrent subscribers (0, 10, 100, 1000, n) and to make it simple a single test (UL, send SMS, t) and execute the same test for each subscriber and call it a success if y% of tests succeed within time T. The way to measure this is easy as well. The lua script would print some data (e.g. the name of the ms) when it starts and completes. For some degrees of freedom I don't have a good idea.. and feedback is welcome. I am not sure if I should spawn, configure, add subscribers, a flavor of Osmocom cellular? I look into having some set of templates for the config, the stack to launch and in concept it looks awfully similar to something the GSM tester is doing. Shall we leave virtbts/cellular to the Osmocom tester and just focus on coordinating mobile? My feeling is to leave this to the Osmo GSM tester. If we have n subscribers I would launch m copies of "mobile" (but run multiple MS in a single binary). So with 4 MS per mobile process and 10k subs we would end with 2.5k processes + many log messages coming from each. Would that scale with python? Should we look into doing this one in Go? Or can some of GSM tester be used (the template part)? I would probably design this concurrently with Go(besides being the first). any ideas/comments? holger

7 years, 3 months

fairwaves HO patches

by Neels Hofmeyr

Hi Ivan, as I'm working towards load-based handover and incorporating your patches, I found that most of it is concerned with libmsc. In contrast, I am currently working on osmo-bsc, in libbsc, and would like to ask your advice. Some parts of the patch aren't easy to understand for me, and I'd like to make sure that I am not dismissing parts of it as non-applicable to libbsc even though they might be important. Since your patches were written, the code has changed. Now that we have the separate osmo-bsc, we will need two layers of handover: intra-BSC and inter-BSC. Intra-BSC is a handover between two cells that are serviced by the same BSC, and the higher layers (MSC) should not even notice that anything has happened -- MSC has asked the BSC to service a call by BSSAP Assignment, and the BSC is free to choose and change around the lchans it assigns to that. That is the layer I'm currently dug into. Inter-BSC is a handover between cells that are serviced by two different BSCs. That seems to be the land your patch is improving. The MSC is involved and so is MNCC. (Both MSC and BSC levels will need their own DTAP cache, and they are by definition completely independent -- MSC caches the DTAP coming from MNCC during Inter-BSC handover, BSC caches DTAP from MSC during Intra-BSC handover.) Since your patch is applied onto openbsc.git, where all of BSC and MSC are still one osmo-nitb, I want to make sure that I sort your patch right. Do some of its semantics apply to osmo-bsc master, even if the code changed? The smaller patches are either already applied to osmo-bsc master, or I've submitted them on gerrit just now: handover_decision: Add more log messages to get more information about HO causes in logs handover_decision: Fix condition for power budget handover attempt handover_logic: set correct link to bts for subscriber_connection in case of moving this connection to another bts Remaining are a small and *the* complex one: transaction: Add new function trans_find_by_lchan handover: Implement proper handover procedure handling at any stage of the call Here is the last one with inline questions, I hope they are not too stupid; or too long, it ended up being a lot to read. Thanks in advance for taking a look: > commit f7f4dc5e3b0dd61b8322946597147baef5d0464b > Author: Ivan Kluchnikov <kluchnikovi(a)gmail.com> > Date: Wed Aug 23 18:09:50 2017 +0300 > > handover: Implement proper handover procedure handling at any stage of the call > > Enhancements for each stage of handover procedure should be implemented in order to support handover at any stage of the call. > For these purposes new in_handover state and ho_queue for call control messages was introduced for gsm_subscriber_connection. > > Stage 1: HO-Command is sent to MS > gsm_subscriber_connection state should be changed to in_handover=1. > In this state all transmission of signalling layer messages (except RR messages needed for handover procedure) > should be suspended until resuming is indicated. > All call control messages for connection received from network side should be buffered in ho_queue. > All call control messages for connection received from MS side should be ignored. > Channel mode modification procedures should be also suspended. > > Stage 2: HO-Detect is received from MS > Audio path should be switched on network side. > > Stage 3-1: HO-Complete is received from MS > Resumption procedure after successful handover should be performed: > - gsm_subscriber_connection state should be changed to normal (in_handover=0). > - all buffered call control messages (ho_queue) should be sent to MS on new lchan. > - suspended channel mode modification procedures should be performed on new lchan. > > Stage 3-2: HO-Fail is received from MS > Resumption procedure after failed handover should be performed: > - gsm_subscriber_connection state should be changed to normal (in_handover=0). > - all buffered call control messages (ho_queue) should be sent to MS on old lchan. > - suspended channel mode modification procedures should be performed on old lchan. > > Stage 3-3: T3103 expired: Handover has failed without HO-Complete or HO-Fail > Resumption procedure should not be performed in case of T3103 expired: > - gsm_subscriber_connection state should be changed to normal (in_handover=0). > - all buffered call control messages (ho_queue) should be cleaned without sending them to MS. > - suspended channel mode modification procedures should not be performed. > > Change-Id: Icb9b5c35ef0c894af2ea762e539f1a9216447fb7 > > diff --git a/openbsc/include/openbsc/bsc_api.h b/openbsc/include/openbsc/bsc_api.h > index 3a931199..baacbeda 100644 > --- a/openbsc/include/openbsc/bsc_api.h > +++ b/openbsc/include/openbsc/bsc_api.h > @@ -51,5 +51,6 @@ int gsm0808_cipher_mode(struct gsm_subscriber_connection *conn, int cipher, > int gsm0808_page(struct gsm_bts *bts, unsigned int page_group, > unsigned int mi_len, uint8_t *mi, int chan_type); > int gsm0808_clear(struct gsm_subscriber_connection *conn); > +int gsm0808_ho_clear(struct gsm_subscriber_connection *conn); > > #endif > diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h > index ac573c49..542b2611 100644 > --- a/openbsc/include/openbsc/gsm_data.h > +++ b/openbsc/include/openbsc/gsm_data.h > @@ -138,6 +138,8 @@ struct gsm_subscriber_connection { > struct gsm_network *network; > > int in_release; > + int in_handover; > + struct llist_head ho_queue; > struct gsm_lchan *lchan; /* BSC */ > struct gsm_lchan *ho_lchan; /* BSC */ > struct gsm_bts *bts; /* BSC */ > diff --git a/openbsc/src/libbsc/bsc_api.c b/openbsc/src/libbsc/bsc_api.c > index 8a4c85ff..71e82d03 100644 > --- a/openbsc/src/libbsc/bsc_api.c > +++ b/openbsc/src/libbsc/bsc_api.c > @@ -253,11 +253,14 @@ struct gsm_subscriber_connection *bsc_subscr_con_allocate(struct gsm_lchan *lcha > conn->bts = lchan->ts->trx->bts; > lchan->conn = conn; > llist_add_tail(&conn->entry, &net->subscr_conns); > + INIT_LLIST_HEAD(&conn->ho_queue); > return conn; > } > > void bsc_subscr_con_free(struct gsm_subscriber_connection *conn) > { > + struct msgb *msg; > + > if (!conn) > return; > > @@ -283,6 +286,11 @@ void bsc_subscr_con_free(struct gsm_subscriber_connection *conn) > conn->secondary_lchan->conn = NULL; > } > > + while (!llist_empty(&conn->ho_queue)) { > + msg = msgb_dequeue(&conn->ho_queue); > + msgb_free(msg); > + } > + > llist_del(&conn->entry); > talloc_free(conn); > } > @@ -747,6 +755,17 @@ int gsm0808_clear(struct gsm_subscriber_connection *conn) > return 0; > } > > +/* > + * Release handover RF Channel. > + */ > +int gsm0808_ho_clear(struct gsm_subscriber_connection *conn) > +{ > + if (conn->ho_lchan) > + bsc_clear_handover(conn, 1); > + > + return 0; > +} > + > static void send_sapi_reject(struct gsm_subscriber_connection *conn, int link_id) > { > struct bsc_api *api; > diff --git a/openbsc/src/libbsc/handover_logic.c b/openbsc/src/libbsc/handover_logic.c > index af4e8013..b7085c34 100644 > --- a/openbsc/src/libbsc/handover_logic.c > +++ b/openbsc/src/libbsc/handover_logic.c > @@ -186,10 +186,17 @@ static void ho_T3103_cb(void *_ho) > { > struct bsc_handover *ho = _ho; > struct gsm_network *net = ho->new_lchan->ts->trx->bts->network; > + struct msgb *msg; > > DEBUGP(DHO, "HO T3103 expired\n"); > rate_ctr_inc(&net->bsc_ctrs->ctr[BSC_CTR_HANDOVER_TIMEOUT]); > > + ho->new_lchan->conn->in_handover = 0; > + while (!llist_empty(&ho->new_lchan->conn->ho_queue)) { > + msg = msgb_dequeue(&ho->new_lchan->conn->ho_queue); > + msgb_free(msg); > + } > + (Your ho_queue seems to live in libbsc, while most of the patch seems to be concerned with libmsc. But nevermind, from jolly's patches I already have a similar queue in osmo-bsc, and we'll probably use yours for libmsc.) > ho->new_lchan->conn->ho_lchan = NULL; > ho->new_lchan->conn = NULL; > lchan_release(ho->new_lchan, 0, RSL_REL_LOCAL_END); > @@ -214,6 +221,8 @@ static int ho_chan_activ_ack(struct gsm_lchan *new_lchan) > > gsm48_send_ho_cmd(ho->old_lchan, new_lchan, 0, ho->ho_ref); > > + new_lchan->conn->in_handover = 1; > + In current osmo-bsc master, we already set conn->ho_lchan before sending out the chan activation request. I'd actually assume setting the flag only now, after the activ ack, is a bit too late? > /* start T3103. We can continue either with T3103 expiration, > * 04.08 HANDOVER COMPLETE or 04.08 HANDOVER FAIL */ > ho->T3103.cb = ho_T3103_cb; > @@ -221,7 +230,8 @@ static int ho_chan_activ_ack(struct gsm_lchan *new_lchan) > osmo_timer_schedule(&ho->T3103, 10, 0); > > /* create a RTP connection */ > - if (is_ipaccess_bts(new_lchan->ts->trx->bts)) > + if (is_ipaccess_bts(new_lchan->ts->trx->bts) && > + new_lchan->tch_mode != GSM48_CMODE_SIGN) > rsl_ipacc_crcx(new_lchan); Please explain ... what case / behavior is this fixing? Do we ever see CMODE_SIGN handovers? Would we also need to check for GSM48_CMODE_DATA_*? > @@ -273,6 +283,11 @@ static int ho_gsm48_ho_compl(struct gsm_lchan *new_lchan) > if (is_e1_bts(new_lchan->conn->bts)) > switch_trau_mux(ho->old_lchan, new_lchan); > > + if (ho->old_lchan->conn->mncc_rtp_connect_pending) { > + new_lchan->abis_ip.connect_port = ho->old_lchan->abis_ip.connect_port; > + new_lchan->abis_ip.connect_ip = ho->old_lchan->abis_ip.connect_ip; > + } > + So if an RTP connect to MNCC is pending, we copy the old lchan's RTP port and IP? Which is this, the MNCC / call router side IP and port? Why not set this at the initiation of the HO already? > @@ -295,27 +310,9 @@ static int ho_gsm48_ho_compl(struct gsm_lchan *new_lchan) > static int ho_gsm48_ho_fail(struct gsm_lchan *old_lchan) > { > struct gsm_network *net = old_lchan->ts->trx->bts->network; > - struct bsc_handover *ho; > - struct gsm_lchan *new_lchan; > - > - ho = bsc_ho_by_old_lchan(old_lchan); > - if (!ho) { > - LOGP(DHO, LOGL_ERROR, "unable to find HO record\n"); > - return -ENODEV; > - } > > rate_ctr_inc(&net->bsc_ctrs->ctr[BSC_CTR_HANDOVER_FAILED]); > > - new_lchan = ho->new_lchan; > - > - /* release the channel and forget about it */ > - ho->new_lchan->conn->ho_lchan = NULL; > - ho->new_lchan->conn = NULL; > - handover_free(ho); > - > - lchan_release(new_lchan, 0, RSL_REL_LOCAL_END); > - > - I'm puzzled by this removal. No actions during ho_fail? Is this really intended, or just some rebase artifact? > return 0; > } > > diff --git a/openbsc/src/libmsc/gsm_04_08.c b/openbsc/src/libmsc/gsm_04_08.c > index e5402d0a..84338d72 100644 > --- a/openbsc/src/libmsc/gsm_04_08.c > +++ b/openbsc/src/libmsc/gsm_04_08.c > @@ -147,6 +147,15 @@ static int gsm48_conn_sendmsg(struct msgb *msg, struct gsm_subscriber_connection > sign_link->trx->bts->nr, > sign_link->trx->nr, msg->lchan->ts->nr, > gh->proto_discr, gh->msg_type); > + > + if (conn->in_handover) { > + msgb_enqueue(&conn->ho_queue, msg); > + DEBUGP(DCC, "(bts %d trx %d ts %d) Suspend message sending to MS, " > + "active HO procedure.\n", > + sign_link->trx->bts->nr, > + sign_link->trx->nr, msg->lchan->ts->nr); > + return 0; > + } (here DTAP handled in libmsc ends up in the ho_queue that otherwise seems to live in libbsc ... as I said above this queue will probably move to libmsc altogether to become part of osmo-msc master.) > } > > return gsm0808_submit_dtap(conn, msg, 0, 0); > @@ -1749,11 +1758,8 @@ static int switch_for_handover(struct gsm_lchan *old_lchan, > struct rtp_socket *old_rs, *new_rs, *other_rs; > > /* Ask the new socket to send to the already known port. */ > - if (new_lchan->conn->mncc_rtp_bridge) { > - LOGP(DHO, LOGL_DEBUG, "Forwarding RTP\n"); > - rsl_ipacc_mdcx(new_lchan, > - old_lchan->abis_ip.connect_ip, > - old_lchan->abis_ip.connect_port, 0); > + if (new_lchan->ts->trx->bts->network->mncc_state) { > + /* Audio path should be switched after receiving ho detect message.*/ > return 0; > } I notice that in the current head, the entire switch_for_handover() has been dropped; it was doing libbsc lchan stuff from within libmsc. Hence we must have added similar logic in osmo-bsc.git and completely dropped this. I think the commit re-implementing handover in osmo-bsc is http://git.osmocom.org/osmo-bsc/commit/?id=39c609b7c924524172ad311bdf89f92b… It appears that lchan->abis_ip.connect_ip and connect_port aren't used at all in osmo-bsc master, but are still present in the struct. I'll ask others about that. In any case, the code base has changed substantially, and this patch hunk no longer applies at all. Am I interpreting this hunk correctly: it moves the ipacc_mdcx to tell the new lchan about its RTP peer to a later stage? In current osmo-bsc master, it seems that this ipacc_mdcx happens as soon as the ipacc_crcx is complete, seen in osmo-bsc/src/osmo-bsc/osmo_bsc_audio.c in handle_abisip_signal(), always using the IP:port the MSC sent us. > > @@ -1821,8 +1827,10 @@ static int handle_abisip_signal(unsigned int subsys, unsigned int signal, > if (subsys != SS_ABISIP) > return 0; > > + net = lchan->ts->trx->bts->network; > + > /* RTP bridge handling */ > - if (lchan->conn && lchan->conn->mncc_rtp_bridge) > + if (lchan->conn && net->mncc_state) > return tch_rtp_signal(lchan, signal); What are the semantics here? It seems odd to move from a check of a conn-specific state (conn->mncc_rtp_bridge) to a check of a global value (net->mncc_state). In any case, this is MNCC related and should not impact Intra-BSC handover, right? > > /* in case we use direct BTS-to-BTS RTP */ > @@ -1851,7 +1859,6 @@ static int handle_abisip_signal(unsigned int subsys, unsigned int signal, > > /* check if any transactions on this lchan still have > * a tch_recv_mncc request pending */ > - net = lchan->ts->trx->bts->network; > llist_for_each_entry(trans, &net->trans_list, entry) { > if (trans->conn && trans->conn->lchan == lchan && trans->tch_recv) { > DEBUGP(DCC, "pending tch_recv_mncc request\n"); > @@ -2017,6 +2024,13 @@ static int tch_recv_mncc(struct gsm_network *net, uint32_t callref, int enable) > switch (bts->type) { > case GSM_BTS_TYPE_NANOBTS: > case GSM_BTS_TYPE_OSMO_SYSMO: > if (ipacc_rtp_direct) { > LOGP(DCC, LOGL_ERROR, "Error: RTP proxy is disabled\n"); > return -EINVAL; > } > + /* RTP bridge handling */ > + if (lchan->conn && net->mncc_state) { > + return 0; > + } If we have a conn and using external MNCC, don't continue at all? I'm not following, would be nice if the comment explained why we need to drop out here. (added some more code context manually) > /* In case, we don't have a RTP socket to the BTS yet, the BTS > * will not be connected to our RTP proxy and the socket will > * not be assigned to the application interface. This method > * will be called again, once the audio socket is created and > * connected. */ > if (!lchan->abis_ip.rtp_socket) { > DEBUGP(DCC, "queue tch_recv_mncc request (%d)\n", enable); > return 0; > } > if (enable) { > /* connect the TCH's to our RTP proxy */ > rc = rsl_ipacc_mdcx_to_rtpsock(lchan); > if (rc < 0) > return rc; > /* assign socket to application interface */ > rtp_socket_upstream(lchan->abis_ip.rtp_socket, > net, callref); > } else > rtp_socket_upstream(lchan->abis_ip.rtp_socket, > net, 0); > break; > > @@ -3325,6 +3339,41 @@ static void mncc_recv_rtp_err(struct gsm_network *net, uint32_t callref, int cmd > return mncc_recv_rtp(net, callref, cmd, 0, 0, 0, 0); > } > > +static void mncc_recv_rtp_modify(struct gsm_lchan *lchan, uint32_t callref) This is to tell the call router that the payload type has changed, right? I've asked in the redmine about whether/how we'd convey an RTP payload change to the MNCC in case of an Intra-BSC handover... https://osmocom.org/issues/1606#note-45 > +{ > + int msg_type; > + struct gsm_network *net = lchan->ts->trx->bts->network; > + > + LOGP(DMNCC, LOGL_NOTICE, "%s sending pending RTP modify ind.\n", > + gsm_lchan_name(lchan)); > + > + switch (lchan->abis_ip.rtp_payload) { > + case RTP_PT_GSM_FULL: > + msg_type = GSM_TCHF_FRAME; > + break; > + case RTP_PT_GSM_EFR: > + msg_type = GSM_TCHF_FRAME_EFR; > + break; > + case RTP_PT_GSM_HALF: > + msg_type = GSM_TCHH_FRAME; > + break; > + case RTP_PT_AMR: > + msg_type = GSM_TCH_FRAME_AMR; > + break; > + default: > + LOGP(DMNCC, LOGL_ERROR, "%s unknown payload type %d\n", > + gsm_lchan_name(lchan), lchan->abis_ip.rtp_payload); > + msg_type = 0; > + break; > + } > + > + mncc_recv_rtp(net, callref, MNCC_RTP_MODIFY, > + lchan->abis_ip.bound_ip, > + lchan->abis_ip.bound_port, > + lchan->abis_ip.rtp_payload, > + msg_type); > +} > + > static int tch_rtp_create(struct gsm_network *net, uint32_t callref) > { > struct gsm_bts *bts; > @@ -3374,6 +3423,9 @@ static int tch_rtp_create(struct gsm_network *net, uint32_t callref) > LOGP(DMNCC, LOGL_DEBUG, "RTP create: codec=%s, chan_type=%s\n", > get_value_string(gsm48_chan_mode_names, m), > get_value_string(gsm_chan_t_names, lchan->type)); > + if (trans->conn->in_handover) { > + return 0; > + } Am I reading right: if we're doing handover, the MSC shouldn't sent another BSSAP Assignment to the BSC; instead, the BSC level figures out another lchan and done ... ? > return gsm0808_assign_req(trans->conn, m, > lchan->type != GSM_LCHAN_TCH_H); > } > @@ -3420,23 +3472,21 @@ static int tch_rtp_connect(struct gsm_network *net, void *arg) > * same package! > */ > trans->conn->mncc_rtp_connect_pending = 1; > + if (trans->conn->in_handover) { > + lchan->abis_ip.connect_port = rtp->port; > + lchan->abis_ip.connect_ip = rtp->ip; > + return 0; > + } > return rsl_ipacc_mdcx(lchan, rtp->ip, rtp->port, 0); We're not telling the BTS about the call router's IP:port anymore? Please explain... > } > > static int tch_rtp_signal(struct gsm_lchan *lchan, int signal) > { > struct gsm_network *net; > - struct gsm_trans *tmp, *trans = NULL; > + struct gsm_trans *trans; > > net = lchan->ts->trx->bts->network; > - llist_for_each_entry(tmp, &net->trans_list, entry) { > - if (!tmp->conn) > - continue; > - if (tmp->conn->lchan != lchan && tmp->conn->ho_lchan != lchan) > - continue; > - trans = tmp; > - break; > - } > + trans = trans_find_by_lchan(lchan); > > if (!trans) { > LOGP(DMNCC, LOGL_ERROR, "%s IPA abis signal but no transaction.\n", > @@ -3459,7 +3509,7 @@ static int tch_rtp_signal(struct gsm_lchan *lchan, int signal) > maybe_switch_for_handover(lchan); > break; > case S_ABISIP_MDCX_ACK: > - if (lchan->conn->mncc_rtp_connect_pending) { > + if (lchan->conn->mncc_rtp_connect_pending && !lchan->conn->in_handover) { if we're in handover, we don't need to tell MNCC that RTP got connected, because that already happened when the call got established initially? So mncc_rtp_connect_pending has a second meaning during handover? > lchan->conn->mncc_rtp_connect_pending = 0; > LOGP(DMNCC, LOGL_NOTICE, "%s sending pending RTP connect ind.\n", > gsm_lchan_name(lchan)); > mncc_recv_rtp_sock(net, trans, MNCC_RTP_CONNECT); > } > break; > @@ -3471,6 +3521,134 @@ static int tch_rtp_signal(struct gsm_lchan *lchan, int signal) > return 0; > } > > +static void ho_queue_clean(struct gsm_subscriber_connection *conn) > +{ > + struct msgb *msg; > + while (!llist_empty(&conn->ho_queue)) { > + msg = msgb_dequeue(&conn->ho_queue); > + msgb_free(msg); > + } > +} > + > +static void ho_resumption(struct gsm_lchan *lchan, struct gsm_trans *trans) > +{ > + struct msgb *msg; > + enum gsm48_chan_mode m; > + > + while (!llist_empty(&lchan->conn->ho_queue)) { > + msg = msgb_dequeue(&lchan->conn->ho_queue); > + gsm48_conn_sendmsg(msg, lchan->conn, trans); > + } > + > + if (trans->conn->mncc_rtp_create_pending && > + lchan->tch_mode == GSM48_CMODE_SIGN) { > + m = mncc_codec_for_mode(lchan->type); > + gsm0808_assign_req(lchan->conn, m, lchan->type != GSM_LCHAN_TCH_H); Wait, now we *do* send a BSSAP Assignment after all? (excuse if I'm being noob, I'm still finding my way through handover in general) shouldn't we rather dequeue the cached DTAP after this instead of before? > + } > + > + if (trans->conn->mncc_rtp_connect_pending) { > + rsl_ipacc_mdcx(lchan, lchan->abis_ip.connect_ip, lchan->abis_ip.connect_port, 0); > + } > +} > + > +static int ho_complete(struct gsm_lchan *new_lchan) > +{ > + struct gsm_trans *trans; > + > + new_lchan->conn->in_handover = 0; > + trans = trans_find_by_lchan(new_lchan); > + if (!trans) { > + LOGP(DHO, LOGL_ERROR, "%s HO detected, but no transaction for new_lchan.\n", > + gsm_lchan_name(new_lchan)); > + ho_queue_clean(new_lchan->conn); > + return 0; > + } > + > + ho_resumption(new_lchan, trans); > + return 0; > +} > + > +static int ho_fail(struct gsm_lchan *old_lchan) > +{ > + struct gsm_trans *trans; > + > + old_lchan->conn->in_handover = 0; > + trans = trans_find_by_lchan(old_lchan); > + if (trans) > + ho_resumption(old_lchan, trans); > + else { > + LOGP(DHO, LOGL_ERROR, "%s HO fail, but no transaction for old_lchan.\n", > + gsm_lchan_name(old_lchan)); > + ho_queue_clean(old_lchan->conn); > + } > + > + gsm0808_ho_clear(old_lchan->conn); > + return 0; > +} > + > +static int ho_detect(struct gsm_lchan *new_lchan) > +{ > + struct gsm_trans *trans; > + struct gsm_lchan *old_lchan; > + > + trans = trans_find_by_lchan(new_lchan); > + > + if (!trans) { > + LOGP(DHO, LOGL_ERROR, "%s HO detected, but no transaction for new_lchan" > + " with enabled tch_recv.\n", > + gsm_lchan_name(new_lchan)); > + return 0; > + } > + > + if (!new_lchan->conn->mncc_rtp_bridge) { > + LOGP(DHO, LOGL_ERROR, "%s HO detected, but connection not in mncc_rtp_bridge mode.\n", > + gsm_lchan_name(new_lchan)); > + return 0; > + } > + > + old_lchan = bsc_handover_pending(new_lchan); > + if (!old_lchan) { > + LOGP(DHO, LOGL_ERROR, "%s HO detected, but no old_lchan for handover.\n", > + gsm_lchan_name(new_lchan)); > + return 0; > + } > + > + LOGP(DHO, LOGL_DEBUG, "HO detected, forwarding RTP\n"); > + rsl_ipacc_mdcx(new_lchan, > + old_lchan->abis_ip.connect_ip, > + old_lchan->abis_ip.connect_port, 0); > + > + mncc_recv_rtp_modify(new_lchan, trans->callref); > + > + return 0; > +} > + > +/* some other part of the code sends us a signal */ > +static int handle_lchan_signal(unsigned int subsys, unsigned int signal, > + void *handler_data, void *signal_data) > +{ > + struct lchan_signal_data *lchan_data; > + struct gsm_lchan *lchan; > + > + lchan_data = signal_data; > + switch (subsys) { > + case SS_LCHAN: > + lchan = lchan_data->lchan; > + if (!lchan->conn) > + return 0; > + switch (signal) { > + case S_LCHAN_HANDOVER_DETECT: > + return ho_detect(lchan); > + case S_LCHAN_HANDOVER_COMPL: > + return ho_complete(lchan); > + case S_LCHAN_HANDOVER_FAIL: > + return ho_fail(lchan); > + } > + break; > + } > + > + return 0; > +} > > static struct downstate { > uint32_t states; > @@ -3853,6 +4031,11 @@ static int gsm0408_rcv_cc(struct gsm_subscriber_connection *conn, struct msgb *m > gsm48_cc_msg_name(msg_type), trans?(trans->cc.state):0, > gsm48_cc_state_name(trans?(trans->cc.state):0)); > > + if (conn->in_handover) { > + DEBUGP(DCC, "Message unhandled, handover procedure.\n"); > + return 0; > + } > + If in handover, drop all CC on the floor? How about a call release, i.e. I hang up while I'm coincidentally being handovered? > /* Create transaction */ > if (!trans) { > DEBUGP(DCC, "Unknown transaction ID %x, " > > > Thanks again! ~N

7 years, 4 months

On the use of 'decmatch' in TTCN-3

by Harald Welte

Hi, I know that TTCN-3 is still new to a lot of you, but we are writing tons of integration testing against the various osmocom programs in it. It is quite amazing technology, and I would like to ask you to bear with me reading this mail :) Pau was stating the question earlier today on not finding an example on how to use decmatch. Indeed, it took me some months to find that gem in the TTCN-3 world. It solves the problem that you often have during test of layered protocol stacks: you have separate encoders/decoders for each protocol layer, and now you want to match on some of the *inner* payload. So normally, you have some kind of header definition + a binary (octetstring) payload. This happens in RSL with the L3_INFO IE, and just the same on BSSAP/DTAP where again the L3 message (for example call control) is encapsulated inside one information element. Now you have multiple options of addressing the problem: a) hand-written calls to the decoder function b) write na 'emulation' for the entire protocol layer c) use decmatch. a) would look like this (pseudo-code): var octetstring l3oct; var RSL_Message rsl RSL.receive(tr_RSL_DATA_REQ(g_chan_nr, ?, ?)) -> value rsl { var PDU_ML3_MS_NW l3 := dec_PDU_ML3_MS_NW(rsl.payload); if (match(l3, some_template)) { ... do something } ... } Which uses the built-in pattern-matching on the RSL port to match any message that matches the tr_RSL_DATA_REQ template, and stores the resulting RSL message in a variable. It then uses an explicit call to the decoder function of the L3 message, and then uses regular conditional expressions for further matching on that inner L3 payload. This is more or less how you would write in C, python or any other quite imperative programming languages. It's very verbose, time consuming and un-abstract/elegant. TTCN-3 has many declarative aspects to it. Code like the above is a waste of your time :) b) would mean that you implement some test component that handles the RSL messages on its bottom side test port, and the L3 messages on its top side test port. That is a possible way, and if you need a lot of state/logic of RSL, it maeks sense. But what if you really simply want to have a match? Then it would be a lot of effort and a large detour. c) decmatch to the rescue! You can write RSL.receive(tr_RSL_DATA_REQ(g_chan_nr, ?, decmatch tr_RRM_RR_STATUS)) which means: * do a receive on the RSL test port, and match on an incoming RSL message that matches the tr_RSL_DATA_REQ template, with channel number specified, link_id any (?), *and* if the octetstring payload, if decoded, matches the template tr_RRM_RR_STATUS ! This is *extremely* powerful and expressive. It allows you to condense complex, parametric template matching over multiple proocol layers. It would in the end match RSL DATA REQUEST, only if they contained a [valid] encoded RR STATUS. See https://gerrit.osmocom.org/6229 for the actual test case I used for the above examples. Please also note that I never had to even write the function name of the decoder (dec_PDU_ML3_MS_NW), but TTCN-3 *automatically* figures out which decoder function it must call in order to decode from the binary octetstring. Happy (TTCN-3) hacking + Osmocom bugfixing, 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)

7 years, 4 months

grcardsim: fails with "bad echo value"

by Marek Sebera

Hi, sim card by identification ATR: 3B 9F 95 80 1F C3 80 31 E0 73 FE 21 13 57 86 81 02 86 98 44 18 A8 GREEN CARD, Grcard (Hong Kong ) Co.,Limited, LTE Usim Card (Telecommunication) Celcom Postpaid 3G (Telecommunication) when trying to program using ./pySim-prog.py -n OpenBSC -i 901700000003080 -c 001 -x 001 -y 02 -s 1791198229180000075 -d /dev/ttyUSB0 -a 58001006 -t grcardsim pySim-prog.py fails with following stacktrace Programming ... Traceback (most recent call last): File "./pySim-prog.py", line 636, in <module> card.program(cp) File "/home/username/pysim/pySim/cards.py", line 271, in program self._scc.verify_chv(5, pin) File "/home/username/pysim/pySim/commands.py", line 111, in verify_chv return self._tp.send_apdu_checksw(self.cla_byte + '2000' + ('%02X' % schv_no) + '08' + fc) File "/home/username/pysim/pySim/transport/__init__.py", line 85, in send_apdu_checksw rv = self.send_apdu(pdu) File "/home/username/pysim/pySim/transport/__init__.py", line 68, in send_apdu data, sw = self.send_apdu_raw(pdu) File "/home/username/pysim/pySim/transport/serial.py", line 202, in send_apdu_raw self._tx_string(pdu[5:]) File "/home/username/pysim/pySim/transport/serial.py", line 168, in _tx_string raise ProtocolError("Bad echo value (Expected: %s, got %s)" % (b2h(s), b2h(r))) pySim.exceptions.ProtocolError: Bad echo value (Expected: 33353338333033303331333033303336, got 3335333833303330333330333033366e) - using usb sim card reader which creates standard serial line on /dev/ttyUSB0 programming also fails when using Gemalto Ezio Shield ./pySim-prog.py -n OpenBSC -i 901700000003080 -c 001 -x 001 -y 02 -s 1791198229180000075 -p 0 -a 58001006 -t grcardsim fails with following stacktrace Programming ... Traceback (most recent call last): File "./pySim-prog.py", line 636, in <module> card.program(cp) File "/home/smarek/Documents/PROJEKTY/SECURITY/TELCO/SIMCARDS/pysim/pySim/cards.py", line 271, in program self._scc.verify_chv(5, pin) File "/home/smarek/Documents/PROJEKTY/SECURITY/TELCO/SIMCARDS/pysim/pySim/commands.py", line 111, in verify_chv return self._tp.send_apdu_checksw(self.cla_byte + '2000' + ('%02X' % chv_no) + '08' + fc) File "/home/smarek/Documents/PROJEKTY/SECURITY/TELCO/SIMCARDS/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 6b00. Thank you for your help MS

7 years, 4 months

Pysim - "Unable to connect with protocol: T0 or T1. Card is unpowered."

by Osmocom Mailing List

Hey, I ordered a generic blank LTE SIM card from ebay. When I try to read it I get the following message. "Unable to connect with protocol: T0 or T1. Card is unpowered." Before you ask, no, the sim is not in the wrong position. Check the attached images. Am I doing something wrong or is the card faulty? The reader is working, I was able to read/write to a SuperSIM (X-sim) and it detected a bunch of commercial SIMs from local operators (wasn't able to read any SIM specific value but I think that's normal). I just want to know if I should open a report agains the seller. Images: https://imgur.com/a/jrtPL Here's the technical data: READER Model: Gemalto PC USB-TR (now, IDBridge CT30) Specifications: https://www.gemalto.com/products/pc_link_readers/index.html SIM (acording to ebay listing) Name: LTE Blank USIM Card SIM Card Size: Standard SIM Card,Micro SIM Card and Nano SIM Card, 3 in 1 Compatible: 4G FDD LTE WCDMA GSM Feature: Can be written ICCID, IMSI, KI, OPC . Application: For Telecommunications Operator Thanks, Filipe Laíns <https://github.com/FFY00> Sent via Migadu.com, world's easiest email hosting

7 years, 4 months

[openbsc 1.0.0.14-98a2ba] testsuite: 4 failed

by Марат Узяков

Hi! Please help!

7 years, 4 months

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OpenBSC January 2018