Commit Graph

119 Commits

Author SHA1 Message Date
Neels Hofmeyr c98b19d4a3 vlr_auth_fsm: add result no_auth_info_event
Add third outcome of auth_fsm: the no_auth_info_event, which should be
dispatched when auth failed because the HLR has no auth info for this
subscriber, i.e. not because an actual auth challenge failed.

No functional change: Handling no_auth_info_event separately follows in
another patch (to allow fallback to no-auth). Feed the same
_E_AUTH_FAILURE as no_auth_info_event to still behave unchanged.

Related: OS#4830
Change-Id: I5103b1f2727f1729a5517ae359df813d50436ed3
2022-10-27 23:54:42 +02:00
Neels Hofmeyr b924ca324c vlr: auth_fsm: rename AUTH_RES to AUTH_SUCCESS
Previous patch added the AUTH_FAILURE event, which means that the
AUTH_RES event now only signals success. Reflect that in the name.

No functional change.

Related: OS#4830
Change-Id: I7124a3591fcf36cee06d7488eeb94f9b85af5dc2
2022-10-27 23:54:42 +02:00
Neels Hofmeyr 977cc508ad vlr: auth_fsm: clarify success/failure result
Explicitly send distinct parent events on auth success and failure. So
far determining success depended only on the data pointer passed on with
the event. Distinct events clarify the logging and the FSM code.

This prepares for a third FSM outcome to be added in a subsequent patch,
to separately signal when the HLR has no auth data.

No functional change.

Related: OS#4830
Change-Id: I02776dfe6785983f2ebe398f57867f5ceb288ba0
2022-10-27 23:54:42 +02:00
Neels Hofmeyr 2c4d40cf7f vlr_lu_fsm: clarify naming of static functions
These functions actually return whether these procedures should be
attempted, not whether they are absolutely required. Rename to avoid
confusion in upcoming patches.

Related: OS#4830
Change-Id: I0ea90476470109134411255ffd1f11d88236c91b
2022-10-27 23:54:42 +02:00
Neels Hofmeyr 2ea7264b86 msc_a,vlr: add is_ciphering_required (accurately named)
For establishing Layer 3, pass a flag from msc_a to VLR that indicates
to fail if encryption is not possible.

An earlier patch [1] renamed a previously existing flag
require_ciphering to is_ciphering_to_be_attempted, because the naming
was not accurate. This new flag now indicates what its name suggests.

This new flag is needed for upcoming patch [2] to distinguish between
optional and mandatory encryption.

[1] Ia55085e3b36feb275bcf92fc91a4be7d1c24a6b9
[2] I5feda196fa481dd8a46b0e4721c64b7c6600f0d1

Related: OS#4830
Change-Id: I52090c5f5db997030da7c2ed9beca9c51f55f4cf
2022-10-27 23:54:00 +02:00
Neels Hofmeyr d99a607ac9 msc_a,vlr: rename ciphering_required to is_ciphering_to_be_attempted
Clarify the name to avoid confusion in upcoming patches.

This function actually returns whether any ciphering mode besides A5/0
is enabled, and does not imply that ciphering is mandatory. A5/0 may
well be allowed when this function returns true.

Related: OS#4830
Change-Id: Ia55085e3b36feb275bcf92fc91a4be7d1c24a6b9
2022-10-27 23:30:30 +02:00
Harald Welte 123261e0bb vlr: Add rate counters and stat items
This should give us some more insight into what is happening inside
the MSC's VLR in terms of number of subcribers, rate of successful /
unsuccessful GSUP procedures, etc.

Related: OS#1974
Change-Id: I681bcfc1875363478190151f2931cad197323ee8
2022-05-15 16:23:02 +02:00
Harald Welte 173bdf303b vlr: Split vlr_subscr_rx_imsi_detach()
The function vlr_subscr_rx_imsi_detach() implies that an explicit IMSI
DETACH was received.  However, that same function was called in other
situations such as timer expiration or GSUP CANCEL.

Let's clean this up by splitting the function into two parts.

No logical change is introduced to the VLR in this patch.

Change-Id: Iffc02f3062ad591ca372a3c6d866066cf63a8830
2022-05-15 15:47:00 +02:00
Vadim Yanitskiy 565ea2ba0c libvlr: fix is_ciph_required(): always send SecModeCmd for UTRAN
Ciphering is optional in both GERAN and UTRAN, however for the later
it's *required* to enable integrity protection for the signalling.
Thus we must always send Security Mode Command in UTRAN, even in
case if ciphering is disabled (UEA0) in the configuration.

The actual decision whether to send CMC/SMC or not is taken in:

  * vlr_access_req_fsm.c / _proc_arq_vlr_node2(), and
  * vlr_lu_fsm.c / vlr_loc_upd_post_auth().

depending on the value returned by is_ciph_required().  Let's
rename this function to is_cmc_smc_required() and ensure that
it always returns true in UTRAN.

This change fixes the Iu test cases in ttcn3-msc-test.

Change-Id: I6205f13453eff7afbf25e013d72ae98a78fcd31b
Fixes: OS#5333
2021-11-30 13:14:16 +00:00
Vadim Yanitskiy f4b87fa83c libvlr: vlr_set_ciph_mode(): avoid redundant check
This function is never called when ciph_required is false, so
there is no need for an additional check in this function.

Change-Id: I900ddd5f1882f8cee234ab1074adcf25830a092c
2021-11-30 09:53:47 +00:00
Pau Espin 35ff852379 cosmetic: Fix typo in comment
Change-Id: Ic167bb4e12c657f917ad4f76ef65f46753c5f7a5
2021-08-25 12:40:36 +02:00
Pau Espin 017ba1fa30 vlr_sgs: Balance use_count incremented in vlr_sgs_loc_update
During a recent pcap trace, it was spotted that subscriber coming from
SGs had a use count with 16 "SGs" items, and later it incremented to 17.
Further investigation shows that the related use_count item was never
decreased, meaning every time an SGs-LU was sent by the MME, the item
was incremented further and never decremented.

Let's rename the item to be referenced while in LU, and then decremented
when LU is done. At that time, either the LU was accepted and the
subscriber object has a use_count item "attached", or it was rejected
and we already sent the reject messages, so we are fine deleting it if
needed.

Related: SYS#5337
Change-Id: I22c386f02ffa57428f700b003cc2cf23133598d0
2021-08-24 14:59:27 +02:00
Pau Espin 25b3ffb5f4 vlr_sgs.c: Fix missing use_count decrease in vlr_sgs_imsi_detach
it was recently observed in a pcap trace with gsmtap_log that the
use_count contained a "vlr_sgs_imsi_detach" item despite no related
message was seen near by. Further investigation shows that there's an
unbalanced get+put code path, introduced by an early return added to fix
another issue.

related: SYS#5337
Fixes: 0803d88d9a
Change-Id: I91ae956e50fca2f4d0e1d145d60ccb0ebfb409e9
2021-08-24 14:59:12 +02:00
Pau Espin eb1b3ab6da vlr_auth_fsm.c: Simplify function auth_fsm_wait_ai_resync
Change-Id: I2070002dea18b728deef5547b4deb6166cfcab6a
2021-08-24 12:25:40 +02:00
Neels Hofmeyr 5bdba0d48d add vlr_subscr_find_by_mi
Will be used by I6fa37d6ca9fcb1637742b40e37b68d67664c9b60
"implement CM Re-Establish for voice calls"

Related: SYS#5130
Change-Id: I5291d098a02268bd1c2e30195ae61e4a13e8709c
2021-07-28 18:37:48 +02:00
Pau Espin 1086e20754 vlr_sgs: Drop recorded LastEutranPlmnId when UE no longer associated
Change-Id: I0dcb1850ab4f6f7d42bfcb19665ddeae2d3b057a
2021-07-02 21:46:49 +02:00
Pau Espin 6710670cb1 Fill Last Used E-UTRAN PLMN Id when in CSFB
Since recently, osmo-bsc behaves strictly as per specs, meaning it will
only send the "Cell selection indicator after release of all TCH and SDCCH IE"
in RR Channel Release iff:
* "Last Used E-UTRAN PLMN Id" was received in the CommonID sent MSC->BSC
* "Last Used E-UTRAN PLMN Id" was received insider "old BSS to new BSS Information"
  in the HandoverRequest sent MSC->BSC.
On the other hand, CSFB_Indicator from ClearCommand MSC->BSC is nw
ignored and not taken into account.

Hence, let's update osmo-msc to also behave correctly by sending the
Last Used E-UTRAN PLMN ID at CommonID tx time to avoid regressions in
CSFB support when running against newer osmo-bsc.

Let's keep sending the CSFB Indicator in ClearCommand as we used too, in
order to keep compatibility with older BSCs (as per spec).

Related: SYS#5337
Change-Id: Ic5f175b179973d0a50d94f00e15f5a3e332605fc
2021-04-29 14:22:33 +02:00
Harald Welte 544a32f271 Send "BSSMAP CommonID" to tell BSC about the IMSI
We're already sending the RANAP CommonID message to the RNC,
let's do the same using BSSMAP CommonId towards the BSC.  This
way the BSC knows about the IMSI of the served subscriber, which
is very useful for logging/debugging.

Change-Id: I2552736477663adb250c55728093500e8ae83ebb
Closes: OS#2969
Depends: libosmocore.git I353adc1aa72377f7d4b3336d2ff47791fb73d62c
2020-08-17 11:17:41 +00:00
Neels Hofmeyr 9aac5c2d21 add rudimentary NRI support for MSC pooling
This patch served for a manual testing counterpart for osmo-bsc to implement
MSC pooling.

This enables a basic MSC pooling setup, but for a production setup, osmo-msc
would still lack various features related to unloading subscribers to another
MSC as explained in 3GPP TS 23.236.

Change-Id: Iafe0878a0a2c8669080d757b34a398ea75fced36
2020-06-19 03:58:13 +02:00
Neels Hofmeyr 46d526a3df use new osmo_mobile_identity API everywhere
Depends: Ic3f969e739654c1e8c387aedeeba5cce07fe2307 (libosmocore)
Change-Id: Idfc8e576e10756aeaacf5569f6178068313eb7ea
2020-06-19 03:58:13 +02:00
Neels Hofmeyr a40adf78c3 vlr_subscr_rx_id_resp(): dont assert on received MI type
The Mobile Identity type is received on the wire, we asserting on its type
constitutes a DoS vector.

Change-Id: I2b2e25ef8e878e91a165018ba49f1609cfb5cbd0
2020-06-03 15:40:39 +00:00
Harald Welte 61ec0295fc vlr_auth_fsm: Fix compilation with gcc-10
See also: https://alioth-lists.debian.net/pipermail/debian-mobcom-maintainers/Week-of-Mon-20200413/000650.html

Change-Id: If3fdbfa20dec02ba57c582700dff12ebbb7d9439
2020-04-20 18:18:18 +00:00
Vadim Yanitskiy 601af0ca00 vlr_sgs_fsm: add missing break, do not call to_null() twice
Change-Id: Ib5d1d7633ca6c32d7d63bb1481f51355c97b90fb
2020-01-27 18:21:08 +00:00
Vadim Yanitskiy 3daf0c2786 vlr: remove unused parameter 'log_level' of auth_fsm_start()
We unconditionally use logging level of the parent FSM anyway.
All callers of auth_fsm_start() always pass fi->log_level.

Change-Id: If2fdf2564eb56d3d94ec3800bdcb0aabcad4e48d
2020-01-27 18:21:08 +00:00
Vadim Yanitskiy fc2b019cd8 libmsc: move subscriber expiration timer T3212 to libvlr
Since the split of OsmoNiTB, OsmoMSC does not deal with the radio
access network directly. Therefore the only purpose of T3212 is to
control subscriber expiration in the local VLR. The timeout value
indicated in System Information Type 3 needs to be configured
separately in the BSC/RNC.

This means that we don't need to store it in deci-hours anymore.
Let's move T3212 to the group of VLR specific timers, so it can
be configured and introspected using the generic 'timer' command,
and deprecate the old '[no] periodic location update' command.

It should be also noted that in the old code subscriber expiration
timeout was actually set to twice the T3212 value plus one minute.
After this change, we apply the configured value 'as-is', but
keep the old behaviour for 'periodic location update' command.

Change-Id: I9b12066599a7c834a53a93acf5902d91273bc74f
2020-01-25 12:49:42 +07:00
Vadim Yanitskiy baf71a72ec libvlr: use generic osmo_tdef API for T3250, T3260, and T3270
These timers so far were implemented as a list of unsigned integers,
which has never been initialized to any reasonable defaults. Since
they are used as state timeouts in several FSMs, we might end up
staying in some state forever.

Let's migrate to generic osmo_tdef API and use default values from
table 11.2 of 3GPP TS 24.008. This way the user can introspect and
change their values from the VTY / configuration file.

Change-Id: Ia8cf98da0aea0e626c5ff088a833d7359c43847f
Related: OS#4368
2020-01-25 10:52:26 +07:00
Neels Hofmeyr 02dd265d68 vlr.c: fix condition to check MSISDN presence
msisdn_enc is a buffer, its address is always != 0

Change-Id: Ib2294d2cd339c36df599d7d134f979a572ac308a
2020-01-06 18:00:40 +01:00
Neels Hofmeyr 27c8b033fc vlr_gsup_rx: fix uninitialized rc
Change-Id: Id7776a473b8356d1d136d78736698f20accc7a36
2020-01-06 18:00:31 +01:00
Neels Hofmeyr 63b246453b gsup: indicate CN-Domain in SendAuthInfo Requests
In order for osmo-hlr to be able to 100% guarantee distinct INDs for CS and PS,
set CN-Domain = CS in all SendAuthInfo Requests.

In Milenage auth, it is highly desirable that osmo-hlr guarantees use of
distinct INDs for CS and PS domains.  If an MSC and SGSN attached at the same
time use the same IND bucket to generate Milenage SQN, that collision would
rapidly waste SQNs and load osmo-hlr with requesting new auth tuples on each
CS/PS Complete-Layer3.

So far, osmo-msc did not indicate the CN domain in the GSUP SendAuthInfo
Request, which was neither required nor evaluated. The CN-Domain is only sent
for the UpdateLocation Request that usually follows later.

Related: OS#4318
Change-Id: I22f44068268e62801cadbf6542efaf153423cd65
2019-12-12 02:10:06 +01:00
Martin Hauke 3f07daceef Fix some typos
Fix typos and common misspellings in code comments and log messages.

Change-Id: Ie66b89065f2100c1d2125ce5a6c9b1d58df7c8ad
2019-11-19 01:04:34 +00:00
Alexander Couzens a09f4987c1 vlr_auth_fsm: on SAI use the GSUP provided GMM cause code
The HLR might respond with a specific GMM cause code. E.g. roaming not
allowed which needs to be passed down the layers.

Change-Id: I9af515dc52834b7c57c42fc3a76ee2c682734e2a
2019-10-17 08:02:07 +00:00
Alexander Couzens 7312b15830 make vlr_gmm_cause_to_mm_cause public
To be used by vlr_auth_fsm

Change-Id: I9e13e756f359a9b9e6a2056ab37adf0af14afec1
2019-10-17 08:01:42 +00:00
Neels Hofmeyr 1bfe0e1cd1 catch GSUP auth result without auth_fsm
When a vlr_subscr receives an Send Auth Info result, properly check whether the
subscriber has an auth_fsm.

Before, a missing auth_fsm would crash osmo-msc with:

    vlr.c:762 Trying to dispatch event 1 to non-existent FSM instance!

Related: OS#4191
Change-Id: I1995d8f68cfde1140968fb9a97bd054de950de2e
2019-09-26 23:05:51 +00:00
Alexander Couzens eb1b03a98a vlr: gmm_cause_to_fsm_and_mm_cause() drop fsm_cause_p argument
It's always set to OSMO_TERM_ERROR. Move the assignment to the caller.
In prepartion to use gmm_cause_to_fsm_and_mm_cause() in vlr_auth_fsm.

Change-Id: Ie4720ad40ef7bcfc528d8d63bfc606c9c0545fb2
2019-09-16 17:57:39 +00:00
Neels Hofmeyr 4b78b29b8c vlr: don't log about "gratuitous ID RESPONSE"
If an ID Response comes in during a non-LU L3 Complete (Paging or CM Service
Request), no event needs to be dispatched. So far vlr_subscr_rx_id_resp()
logged a NOTICE "gratuitous ID RESPONSE?!?" if no lu_fsm is present.

An ID Response can come in particularly as payload with a BSSMAP Cipher Mode
Complete message, even though osmo-msc didn't explicitly ask for it.

It is not an error to get a Cipher Mode Complete containing an ID Response
during Paging or CM Service Request, so remove the confusing log message.

Related: OS#4168 (only loosely related)
Change-Id: I8a5b8735eb41cd0976c7ab32cdd55440d3ef70ac
2019-09-03 13:59:05 +00:00
Neels Hofmeyr 364f927ac4 vlr_lu_fsm: ignore ID_IMEISV during VLR_ULA_S_WAIT_HLR_UPD
Change-Id: I2ea4f46efa013671d93892cb07bf830393289150
2019-08-29 05:42:02 +00:00
Vadim Yanitskiy ed73ae13a1 libvlr/vlr.c: cosmetic: move message_type assignment
Change-Id: Ice7f98597b54f03069375fac56fb162f2669e7f0
2019-08-18 11:11:44 +00:00
Neels Hofmeyr 106ba523c8 vlr_lu_fsm: fix missing event for IMEISV
Event VLR_ULA_E_ID_IMEISV is listed as permitted in VLR_ULA_S_WAIT_LU_COMPL,
but is missing from the switch() on the incoming event. So, sending an IMEISV
identity during the WAIT_LU_COMPL state would crash osmo-msc.

When receiving an IMEISV, vlr_subscr_set_imeisv() in turn calls
vlr_subscr_set_imei(), so as far as the lu_fsm is concerned, receiving an
IMEISV is identical to receiving an IMEI, and it can continue to send a Check
IMEI request to the HLR. Thus simply add VLR_ULA_E_ID_IMEISV to the
VLR_ULA_E_ID_IMEI switch case.

Change-Id: I11106cb108a4b1406ff9a8b8ff5761440a274dad
2019-08-08 02:08:55 +02:00
Oliver Smith c0a5e71d0e vlr_lu_fsm.c: don't send LU reject twice
Don't call tx_lu_rej() in the "vlr_lu_compl" FSM. It is always getting
called in the parent "lu" FSM and is therefore redundant:

_vlr_lu_compl_fsm_done(fi, VLR_FSM_RESULT_FAILURE, cause)
-> osmo_fsm_inst_state_chg(fi, LU_COMPL_VLR_S_DONE, 0, 0)
-> vlr_lu_compl_fsm_dispatch_result()
-> lu_fsm_wait_lu_compl()/lu_fsm_wait_lu_compl_standalone()
-> lu_fsm_failure()
-> lfp->vlr->ops.tx_lu_rej()

I have noticed the bug with the TTCN3 tests. This patch fixes
TC_lu_imsi_auth_tmsi_check_imei_{nack,err} after stricter checking
in [1] and also TC_iu_mo_crcx_ran_reject.

[1] I836f76242463789c4c003feec757714827f2a31b (osmo-ttcn3-hacks)
Change-Id: I127b27937613ea0ff29d67991c0414fca6d441d9
2019-07-24 09:08:22 +02:00
Vadim Yanitskiy 718f32fa88 libvlr/vlr.c: do not expire subscribers if periodic LU is disabled
When periodic Location Update is disabled (T3212 = 0), it was noticed
that OsmoMSC does expire subscribers quite soon - after 60 seconds
(VLR_SUBSCRIBER_LU_EXPIRATION_INTERVAL) since the last LU.

In order to avoid that, we need to check T3212 timer value in
vlr_subscr_expire_lu(), and if it's equal to 0, do not expire
anybody until the explicit IMSI Detach.

Change-Id: I2ead2241a3394dbdd5417f4554190df3fd698af2
2019-06-19 14:36:28 +07:00
Eric Wild 58abc67caa libvlr: fix sgsn tmsi creation, replace constant with define
reported by _dev_zero in #osmocom

Change-Id: Ib5679ab5d06b6ef735725b4a68eeb1e9cbcc11ba
Depends-On: libosmocore I52b9f6b5f3e96d85a390ba2af21d7814df8aaeec
2019-06-17 12:51:27 +00:00
Philipp Maier 483cea889c sgs_iface: detect and react to VLR/HLR failure
The HLR (which is connected via the GSUP interface) may fail and
disconnect. On the next location update the VLR will try to talk to the
HLR and fail. This failure event is not communicated towards the SGs
related code and the SGs-association will remain in the LA-PRESENT state
forever. Lets add code to report the problem to the SGs code and trigger
a RESET an the SGs interface.

- Add a flag to report an HLR problem back to the SGs code
- Fix the FSM that controls the reset
- Make sure the all SGs associations are reset when the failure occurs.

Change-Id: Icc7df92879728bc98c85fc1d5d8b4c6246501b12
Related: OS#3859
2019-05-27 11:49:50 +00:00
Oliver Smith cbf2c93d11 vlr: optionally send IMEI early to HLR
When 'check-imei-rqd 1 early' is set in the config, send the IMEI to
the HLR before doing the location update with the HLR.

The OsmoHLR documentation referenced in the code will be added in
osmo-hlr.git's Change-Id I2dd4a56f7b8be8b5d0e6fc32e04459e5e278d0a9.

Related: OS#2542
Change-Id: I88283cad23793b475445d814ff49db534cb41244
2019-05-15 10:57:43 +02:00
Oliver Smith b8077b0c1d vlr: when setting IMEISV, also set IMEI
Copy IMEISV to IMEI when IMEISV changes. The additional SV digits will
get cut off then. This is needed for the subscriber on demand use case,
since we can get the IMEISV early (see [1]), but need to send the IMEI
to the Check IMEI procedure.

While adjusting the tests, I have noticed that there are code paths
where we ask the MS for the IMEISV first, and later ask the MS for the
IMEI, although we already have the IMEISV. This could be improved in a
future patch.

[1] Change-Id I256224194c3b8caf2b58a88d11dccd32c569201f

Related: OS#2542
Change-Id: I02e7b66848bf7dddb31b105e2ae981432817ae1e
2019-05-15 10:57:43 +02:00
Oliver Smith ffd522ec6f vlr_lu_fsm.c: assert for invalid events
In state machine callback functions, instead of logging an error when
an invalid event arrives, do OSMO_ASSERT(0).

Change-Id: If5363ae37b414a0ac195e5f89664c75cbad0bb21
2019-05-14 08:19:52 +00:00
Neels Hofmeyr c4628a3ad4 large refactoring: support inter-BSC and inter-MSC Handover
3GPP TS 49.008 '4.3 Roles of MSC-A, MSC-I and MSC-T' defines distinct roles:
- MSC-A is responsible for managing subscribers,
- MSC-I is the gateway to the RAN.
- MSC-T is a second transitory gateway to another RAN during Handover.

After inter-MSC Handover, the MSC-I is handled by a remote MSC instance, while
the original MSC-A retains the responsibility of subscriber management.

MSC-T exists in this patch but is not yet used, since Handover is only prepared
for, not yet implemented.

Facilitate Inter-MSC and inter-BSC Handover by the same internal split of MSC
roles.

Compared to inter-MSC Handover, mere inter-BSC has the obvious simplifications:
- all of MSC-A, MSC-I and MSC-T roles will be served by the same osmo-msc
  instance,
- messages between MSC-A and MSC-{I,T} don't need to be routed via E-interface
  (GSUP),
- no call routing between MSC-A and -I via MNCC necessary.

This is the largest code bomb I have submitted, ever. Out of principle, I
apologize to everyone trying to read this as a whole. Unfortunately, I see no
sense in trying to split this patch into smaller bits. It would be a huge
amount of work to introduce these changes in separate chunks, especially if
each should in turn be useful and pass all test suites. So, unfortunately, we
are stuck with this code bomb.

The following are some details and rationale for this rather huge refactoring:

* separate MSC subscriber management from ran_conn

struct ran_conn is reduced from the pivotal subscriber management entity it has
been so far to a mere storage for an SCCP connection ID and an MSC subscriber
reference.

The new pivotal subscriber management entity is struct msc_a -- struct msub
lists the msc_a, msc_i, msc_t roles, the vast majority of code paths however
use msc_a, since MSC-A is where all the interesting stuff happens.

Before handover, msc_i is an FSM implementation that encodes to the local
ran_conn. After inter-MSC Handover, msc_i is a compatible but different FSM
implementation that instead forwards via/from GSUP. Same goes for the msc_a
struct: if osmo-msc is the MSC-I "RAN proxy" for a remote MSC-A role, the
msc_a->fi is an FSM implementation that merely forwards via/from GSUP.

* New SCCP implementation for RAN access

To be able to forward BSSAP and RANAP messages via the GSUP interface, the
individual message layers need to be cleanly separated. The IuCS implementation
used until now (iu_client from libosmo-ranap) did not provide this level of
separation, and needed a complete rewrite. It was trivial to implement this in
such a way that both BSSAP and RANAP can be handled by the same SCCP code,
hence the new SCCP-RAN layer also replaces BSSAP handling.

sccp_ran.h: struct sccp_ran_inst provides an abstract handler for incoming RAN
connections. A set of callback functions provides implementation specific
details.

* RAN Abstraction (BSSAP vs. RANAP)

The common SCCP implementation did set the theme for the remaining refactoring:
make all other MSC code paths entirely RAN-implementation-agnostic.

ran_infra.c provides data structures that list RAN implementation specifics,
from logging to RAN de-/encoding to SCCP callbacks and timers. A ran_infra
pointer hence allows complete abstraction of RAN implementations:

- managing connected RAN peers (BSC, RNC) in ran_peer.c,
- classifying and de-/encoding RAN PDUs,
- recording connected LACs and cell IDs and sending out Paging requests to
  matching RAN peers.

* RAN RESET now also for RANAP

ran_peer.c absorbs the reset_fsm from a_reset.c; in consequence, RANAP also
supports proper RESET semantics now. Hence osmo-hnbgw now also needs to provide
proper RESET handling, which it so far duly ignores. (TODO)

* RAN de-/encoding abstraction

The RAN abstraction mentioned above serves not only to separate RANAP and BSSAP
implementations transparently, but also to be able to optionally handle RAN on
distinct levels. Before Handover, all RAN messages are handled by the MSC-A
role.  However, after an inter-MSC Handover, a standalone MSC-I will need to
decode RAN PDUs, at least in order to manage Assignment of RTP streams between
BSS/RNC and MNCC call forwarding.

ran_msg.h provides a common API with abstraction for:

- receiving events from RAN, i.e. passing RAN decode from the BSC/RNC and
  MS/UE: struct ran_dec_msg represents RAN messages decoded from either BSSMAP
  or RANAP;
- sending RAN events: ran_enc_msg is the counterpart to compose RAN messages
  that should be encoded to either BSSMAP or RANAP and passed down to the
  BSC/RNC and MS/UE.

The RAN-specific implementations are completely contained by ran_msg_a.c and
ran_msg_iu.c.

In particular, Assignment and Ciphering have so far been distinct code paths
for BSSAP and RANAP, with switch(via_ran){...} statements all over the place.
Using RAN_DEC_* and RAN_ENC_* abstractions, these are now completely unified.

Note that SGs does not qualify for RAN abstraction: the SGs interface always
remains with the MSC-A role, and SGs messages follow quite distinct semantics
from the fairly similar GERAN and UTRAN.

* MGW and RTP stream management

So far, managing MGW endpoints via MGCP was tightly glued in-between
GSM-04.08-CC on the one and MNCC on the other side. Prepare for switching RTP
streams between different RAN peers by moving to object-oriented
implementations: implement struct call_leg and struct rtp_stream with distinct
FSMs each. For MGW communication, use the osmo_mgcpc_ep API that has originated
from osmo-bsc and recently moved to libosmo-mgcp-client for this purpose.
Instead of implementing a sequence of events with code duplication for the RAN
and CN sides, the idea is to manage each RTP stream separately by firing and
receiving events as soon as codecs and RTP ports are negotiated, and letting
the individual FSMs take care of the MGW management "asynchronously". The
caller provides event IDs and an FSM instance that should be notified of RTP
stream setup progress. Hence it becomes possible to reconnect RTP streams from
one GSM-04.08-CC to another (inter-BSC Handover) or between CC and MNCC RTP
peers (inter-MSC Handover) without duplicating the MGCP code for each
transition.

The number of FSM implementations used for MGCP handling may seem a bit of an
overkill. But in fact, the number of perspectives on RTP forwarding are far
from trivial:
- an MGW endpoint is an entity with N connections, and MGCP "sessions" for
  configuring them by talking to the MGW;
- an RTP stream is a remote peer connected to one of the endpoint's
  connections, which is asynchronously notified of codec and RTP port choices;
- a call leg is the higher level view on either an MT or MO side of a voice
  call, a combination of two RTP streams to forward between two remote peers.

  BSC                 MGW                PBX
                CI          CI
                [MGW-endpoint]
  [--rtp_stream--]          [--rtp_stream--]
  [----------------call_leg----------------]

* Use counts

Introduce using the new osmo_use_count API added to libosmocore for this
purpose. Each use token has a distinct name in the logging, which can be a
globally constant name or ad-hoc, like the local __func__ string constant.  Use
in the new struct msc_a, as well as change vlr_subscr to the new osmo_use_count
API.

* FSM Timeouts

Introduce using the new osmo_tdef API, which provides a common VTY
implementation for all timer numbers, and FSM state transitions with the
correct timeout. Originated in osmo-bsc, recently moved to libosmocore.

Depends: Ife31e6798b4e728a23913179e346552a7dd338c0 (libosmocore)
         Ib9af67b100c4583342a2103669732dab2e577b04 (libosmocore)
	 Id617265337f09dfb6ddfe111ef5e578cd3dc9f63 (libosmocore)
	 Ie9e2add7bbfae651c04e230d62e37cebeb91b0f5 (libosmo-sccp)
	 I26be5c4b06a680f25f19797407ab56a5a4880ddc (osmo-mgw)
	 Ida0e59f9a1f2dd18efea0a51680a67b69f141efa (osmo-mgw)
	 I9a3effd38e72841529df6c135c077116981dea36 (osmo-mgw)
Change-Id: I27e4988e0371808b512c757d2b52ada1615067bd
2019-05-08 17:02:32 +02:00
Neels Hofmeyr 5b1e0309b5 fix various missing line endings in logging
Change-Id: I013eb0eeb5673c06034465020e5dc5230f45ddf5
2019-05-06 23:45:28 +02:00
Philipp Maier bb5ba8b7df vlr_sgs_fsm: make sure vsub is marked used when LA is present
When the LU is accepted and the subscriber (vsub) is not claimed as "in
use" in the ref counting system.

- Make sure vlr_subscr_get() is called when the LU is accepted.

Change-Id: Iba90be095569cc5212c61ab8e8a9bfd4ae51fd44
Related OS#3934
2019-04-17 12:50:07 +02:00
Neels Hofmeyr 7c5346cd70 vlr_subscr: use osmo_use_count
Depends: Ife31e6798b4e728a23913179e346552a7dd338c0 (libosmocore)
Change-Id: Ib06d030e8464abe415ff597d462ed40eeddef475
2019-04-12 02:15:25 +02:00
Philipp Maier 4826465708 vlr_sgs: start lu expiration timer on sgs eps detach
When the subscriber is detached from SGs services (but not from 2g
services). Then the subscriber essentially becomes a regular 2g
subscriber, which means thet the lu expiration timer needs to be
started.

Change-Id: If95c63706dc1c5a537f7cd1b6481252427cbf234
Related: OS#3614
2019-04-07 18:57:39 +00:00