From 3GPP TS 48.008 sec 3.1.30 "Common ID":
"""
If the SCCP connection is established due to CSFB from E-UTRAN and the MSC supports
return to the last used PLMN after CS fallback, then it should send the COMMON ID message
to the BSS including the Last used E-UTRAN PLMN ID information element if available at
the MSC immediately following the successful SCCP connection setup.
"""
Furthermore, 3GPP TS 48.008 version 16.0.0 Release 16 "3.2.1.21 CLEAR COMMAND",
for field CSFB Indication, states:
"""
NOTE: This information element doesn't serve any useful purpose. MSCs should not send the
information element unless it is required by the recipients (due to the need to interwork
with older versions of the protocol). It is expected that in future versions of the present
document, this information element will be deleted from this message.
"""
Hence, build up the EUTRAN neighbor list based on whether we received
the Last E-UTRAN PLMN ID IE during Common Id. In the future, we should
probably filter the list while populating it based on the received IE.
This change will also allow reusing same mechanism for SRVCC
EUTRAN->GERAN support, where te Last E-UTRAN PLMN ID IE can be found
inside "Old BSS to New BSS information" IE in msg HANDOVER REQUEST.
Related: SYS#5337
Change-Id: I5d290ac55eca5adde1c33396422f4c10b83c03d5
The N-CONNECT.req on the A interface is a possible *consequence* of the event
being handled, namely the incoming RSL ESTablish INDication containing the
Complete Layer 3 message: dispatched by bsc_compl_l3().
If an (LCS related) connection is already present on the A-interface when the
lchan is established, there will be no N-CONNECT but an N-DATA sending the
Complete Layer 3. See BSC_Tests.TC_cm_service_during_lcs_loc_req().
Change-Id: Ic43aabeb0d3c58ac62249ad9d3718363d32508f9
During LCS development, I'm getting use count bugs and would like to see use
token strings to figure it out.
Change-Id: I29bf60059d4cf7bb99a00753e6cdc149baf95f94
The MSC may at any time send a BSSMAP CommonID message via a
SCCP connection to inform us of the IMSI of the subscriber. Let's
make use of that information by associating a related bsc_subscr
and updating the identity of the bsc_subscr_conn_fsm for improved
logging / filtering.
Closes: OS#2969
Change-Id: I52c43fb940f0db796adf4c0adb2260321c721c39
When the BTS is is not an ipaccess BTS, the BTS can only be an E1 bts.
In that case E1 endpoints must be used and there will be no RTP stream
setup towards the BTS.
Change-Id: I4f1f39bf90b0a7c9ea448dab255daf99cd36bb4a
Related: OS#2547
In lchan.release, add 'cause_rr', and set RR Channel Release message's cause
value to lchan.release.cause_rr.
In lchan_release(), do not set lchan.release.rsl_error_cause to the RR cause
value, these are unrelated. Store in new lchan.release.cause_rr instead. The
rsl_error_cause is apparently only used for logging, except for one place in
lchan_fsm_wait_activ_ack() that compares it to RSL_ERR_RCH_ALR_ACTV_ALLOC, so
there should not be a functional difference by this fix.
Propagate the BSSMAP Clear Command cause to the RR Channel Release:
Add struct gscon_clear_cmd_data as event data for GSCON_EV_A_CLEAR_CMD -- so
far it sent the is_csfb flag, add the gsm0808_cause; invoking the event happens
in bssmap_handle_clear_cmd().
Adjust event handling in gscon_fsm_allstate(); there, pass the cause to
gscon_release_lchans(). In gscon_release_lchans(), pass the cause to
gscon_release_lchan(), and then lchan_release(), which sets the new
lchan.release.cause_rr to the passed cause value.
As soon as the lchan FSM enters the proper state, it calls
gsm48_send_rr_release(). There, set the cause value in the encoded message to
lchan.release.cause_rr.
Interworking with osmo-msc: so far, osmo-msc fails to set the Clear Command
cause code for normal release, it just passes 0 which amounts to
GSM0808_CAUSE_RADIO_INTERFACE_MESSAGE_FAILURE. Before this patch, osmo-bsc
always sent GSM48_RR_CAUSE_NORMAL in the RR Channel Release, and after this
patch it will receive 0 == GSM0808_CAUSE_RADIO_INTERFACE_MESSAGE_FAILURE from
osmo-msc and more accurately translate that to GSM48_RR_CAUSE_PROT_ERROR_UNSPC.
This means in practice that we will now see an error cause in RR Channel
Release instead of GSM48_RR_CAUSE_NORMAL when working with osmo-msc. For
changing osmo-msc to send GSM0808_CAUSE_CALL_CONTROL instead (which translates
to GSM48_RR_CAUSE_NORMAL), see OS#4664 and change-id
I1347ed72ae7d7ea73a557b866e764819c5ef8c42 (osmo-msc).
A test for this is in Ie6c99f28b610a67f2d59ec00b3541940e882251b
(osmo-ttcn3-hacks).
Related: SYS#4872
Change-Id: I734cc55c501d61bbdadee81a223b26f9df57f959
osmo-mgw.git also includes fixes of the MGW endpoint FSM, for example
I92a9944acc96398acd6649f9c3c5badec5dd6dcc.
Depends: I9a3effd38e72841529df6c135c077116981dea36 (osmo-mgw)
Change-Id: I03e6b48d9b0a5370310d5f56809259ff7909cf9d
If an lchan is being released and had a SACCH active, there is no reason to
omit the Deact SACCH message ever. All of the callers that passed
do_deact_sacch = false did so for no good reason.
Drop the do_deact_sacch flag everywhere and, when the lchan type matches and
SAPI[0] is still active, simply always send a Deact SACCH message.
The do_deact_sacch flag was carried over from legacy code, by me, mainly
because I never really understood why it was there. I do hope I'm correct now,
asserting that having this flag makes no sense.
Change-Id: Id3301df059582da2377ef82feae554e94fa42035
After commit [1], the code makes sure to disassociate lchan and conn before
invoking the lchan release. However, we only send RR Release if a conn is
present, which clearly is nonsense after [1].
[1] commit 8b818a01b0
"subscr conn: properly forget lchan before release"
Change-Id: I4fd582b41ba4599af704d670af83651d2450b1db
Manage sending of RR Release via a flag, set during invoking lchan release.
Add do_rr_release arg to lchan_release(), gscon_release_lchans(). In
lchan_fsm.c, send RR Release only if do_rr_release was passed true; do not care
whether a conn is still associated (because it won't ever be since [1]).
That way we can intelligently decide what release process makes sense (whether
the lchan terminates the subscriber connection or whether the connection goes
on at another lchan), and still disassociate lchan and conn early.
BTW, this problem wasn't caught by the stock OsmoBSC TTCN3 tests, because the
f_expect_chan_rel() don't care whether an RR Release happens or not. This is
being fixed by Ibc64058f1e214bea585f4e8dcb66f3df8ead3845.
So far this patch should fix BSC_Tests_LCLS.TC_lcls_connect_clear.
Related: OS#3413
Change-Id: I666b3b4f45706d898d664d380bd0fd2b018be358
Add FSMs:
- timeslot_fsm: handle dynamic timeslots and OML+RSL availability.
- lchan_fsm: handle an individual lchan activation, RTP stream and release,
signal the appropriate calling FSMs on success, failure, release.
- mgw_endpoint_fsm: handle one entire endpoint with several CI.
- assignment_fsm: BSSMAP Assignment Request.
- handover_fsm: all of intra, inter-MO and inter-MT handover.
Above FSMs absorb large parts of the gscon FSM. The gscon FSM was surpassing
the maximum amount events (32), and it is more logical to treat assignment,
handover and MGW procedures in separate FSMs.
- Add logging macros for each FSM type:
- LOG_TS()
- LOG_LCHAN()
- LOG_MGWEP(), LOG_CI()
- LOG_ASSIGNMENT()
- LOG_HO()
These log with the osmo_fsm_inst where present.
New style decision: logging without a final newline char is awkward,
especially for gsmtap logging and when other logs interleave LOGPC() calls;
we have various cases where the final \n goes missing, and also this invokes
the log category checking N times instead of once.
So I decided to make these macros *always* append a newline, but only if
there is no final newline yet. I hope that the compiler optimizes the
strlen() of the constant format strings away. Thus I can log with or without
typing "\n" and always get an \n termination anyway.
General:
- replace osmo_timers, state enums and program-wide osmo_signal_dispatch()
with dedicated FSM timeouts, states and events.
- introduce a common way to handle Tnnn timers: gsm_timers.h/.c: struct T_def.
These can be used (with some macro magic) to define a state's timeout once,
and not make mistakes for each osmo_fsm_inst_state_chg().
Details:
bsc_subscr_conn_fsm.c:
- move most states of this FSM to lchan_fsm, assignment_fsm, handover_fsm and
mgw_endpoint_fsm.
- There is exactly one state for an ongoing Assignment, with all details
handled in conn->assignment.fi. The state relies on the assignment_fsm's
timeout.
- There is one state for an ongoing Handover; except for an incoming Handover
from a remote BSS, the gscon remains in ST_INIT until the new lchan and conn
are both established.
- move bssmap_add_lcls_status() to osmo_bsc_lcls.c
abis_rsl.c:
- move all dynamic timeslot logic away into timeslot_fsm. Only keep plain send/receive functions in
abis_rsl.c
- reduce some rsl functions to merely send a message, rename to "_tx_".
- rsl_ipacc_mdcx(): add '_tx_' in the name; move parts that change the lchan state out into the
lchan_fsm, the lchan->abis_ip.* are now set there prior to invoking this function.
- move all timers and error/release handling away into various FSMs.
- tweak ipa_smod_s_for_lchan() and ipa_rtp_pt_for_lchan() to not require an
lchan passed, but just mode,type that they require. Rename to
ipacc_speech_mode*() and ipacc_payload_type().
- add rsl_forward_layer3_info, used for inter-BSC HO MO, to just send the RR
message received during BSSMAP Handover Command.
- move various logging to LOG_LCHAN() in order to log with the lchan FSM instance.
One drawback is that the lchan FSM is limited to one logging category, i.e. this moves some logging
from DRR to DRSL. It might actually make sense to combine those categories.
- lose LOGP...LOGPC logging cascades: they are bad for gsmtap logging and for performance.
- handle_classmark_chg(): change logging, move cm2 len check out of the cm3 condition (I hope that's
correct).
- gsm48_send_ho_cmd(): split off gsm48_make_ho_cmd() which doesn't send right away, so that during
inter-bsc HO we can make an RR Handover Command to send via the MSC to the remote BSS.
assignment_fsm.c:
- the Chan Mode Modify in case of re-using the same lchan is not implemented
yet, because this was also missing in the previous implementation (OS#3357).
osmo_bsc_api.c:
- simplify bsc_mr_config() and move to lchan_fsm.c, the only caller; rename to
lchan_mr_config(). (bsc_mr_config() used to copy the values to mr_bts_lv
twice, once by member assignment and then again with a memcpy.)
- During handover, we used to copy the MR config from the old lchan. Since we
may handover between FR and HR, rather set the MR Config anew every time, so
that FR rates are always available on FR lchans, and never on HR lchans.
Depends: I03ee7ce840ecfa0b6a33358e7385528aabd4873f (libosmocore),
I1f2918418c38918c5ac70acaa51a47adfca12b5e (libosmocore)
Change-Id: I82e3f918295daa83274a4cf803f046979f284366
In certain situations like handover or assignment, DTAP must not go out via RSL
directly but is cached to be submitted later. Make sure that all RSL DTAP
sending adheres to this:
gscon_submit_rsl_dtap() is the new "public" API to request an RSL DTAP to be
sent. Depending on the gscon's state, this ends up in the cache or is sent
directly. When caching, there is no way to tell whether sending will succeed or
not, so semantically it does not make sense to even return a result code. Just
return void. Change all "public" callers to gscon_submit_rsl_dtap().
Merge gsm0808_submit_dtap() and submit_dtap() guts to gsm0808_send_rsl_dtap(),
static in bsc_subscr_conn_fsm.c: directly send DTAP, assume a conn->lchan to be
present, or otherwise trigger a BSSMAP Clear Request.
The static submit_dtap() becomes a thin convenience wrapper.
Move ho_dtap_cache* functions to bsc_subscr_conn_fsm.c and rename to
gscon_dtap_cache_* -- they are not only for handover, also for assignment.
Function gsm0808_submit_dtap() m
Introduce function gscon_submit_rsl_dtap()
Change-Id: I6ffd7aa641c8905292c769400048c96aa0949585
While GSCON is setting the codec info when operating on the MGW, LCLS
is not doing that yet. This means that the MDCX messages that are
sent by LCLS do not contain any payload type and also no ptime or
rtpmap fields. This also causes the following TTCN3 tests to fail:
TC_lcls_connect_break
TC_lcls_connect_clear
TC_lcls_gcr_bway_connect
TC_lcls_gcr_bway_dont_connect_csc
- Make mgcp_pick_codec() public as bsc_subscr_pick_codec()
- use bsc_subscr_pick_codec() to set codec info in osmo_bsc_lcls.c
Change-Id: I383d55fa602cda0926dd701ee517a299db578260
Closes: OS#3358
This code contains the following code:
* receive/parse/interpret LCLS specific BSSMAP IEs and PDUs
* osmo_fsm handling the various states and their transitions
* call leg correlation (finding the other subscr_conn with same GCR)
* communication between the two call-leg LCLS FSMs
* detection of supported / unsupported LCLS configurations
* display of GCR / LCLS information in "show conns"
* switch the media streams locally using MDCX to the MGW
Closes: OS#1602
Change-Id: I614fade62834def5cafc94c4d2578cd747a3f9f7
The state ST_WAIT_MODE_MODIFY_ACK can never be reached by the
current FSM model.
- Remove ST_WAIT_MODE_MODIFY_ACK and all related code
Change-Id: Iacaae2ee50ca1956066b7dce4517bbc9c2b0897e
Related: OS#2762
In the current implementation of osmo-bsc, the subscriber connection is
not handled (very) statefully. However, there is some state keeping in the
code that handles the mgcp connection, but there are still to much loose ends
which allow odd situations to happen, which then lead severe error situations
(see also closes tags at the end) This commit adds a number of improvements
to fix those problems.
- Use an osmo-fsm to control the gsm_subscriber_connection state and
make sure that certain operations can only take place at certain states
(e.g let connection oriented SCCP traffic only pass when an SCCP connection
actually exists.
Remove the old osmo_bsc_mgcp.c code. Use the recently developed MGCP client
FSM to handle the MGCP connections.
Also make sure that stuff that already works does not break. This in
particular refers to the internal handover capability and the respective
unit-tests.
See also OS#2823, OS#2768 and OS#2898
- Fix logic to permit assignment to a signalling channel. (OS#2762)
- Introduce T993210 to release lchan + subscr_conn if MSC fails to respond
The GSM specs don't have an explicit timer for this, so let's introdcue
a custom timer (hence starting with 99).
This timeout catches the following situation:
* we send a SCCP CR with COMPL_L3_INFO from the MS to the MSC,
* the MSC doesn't respond (e.g. SCCP routing failure, program down, ...)
The MS is supposed to timeout with T3210, 3220 or 3230. But the BSC
shouldn't trust the MS but have some timer on its own.
SCCP would have a timer T(conn est), but that one is specified to be
1-2min and hence rather long.
See also: OS#2775
- Terminate bsc_subscr_conn_fsm on SCCP N-DISC.ind from MSC
If the MSC is disconnecting the SCCP channel, we must terminate the FSM
which in turn will release all lchan's and other state.
This makes TC_chan_rel_hard_rlsd pass, see also OS#2731
As a side-effect, this fixes TC_chan_act_ack_est_ind_refused(),
where the MSC is answering with CREF to our CR/COMPL_L3.
- Release subscriber connection on RLL RELEASE IND of SAPI0 on main DCCH
The subscriber connection isn't really useful for anything after the
SAPI0 main signalling link has been released. We could try to
re-establish, but our best option is probably simply releasing the
subscriber_conn and anything related to it.
This will make TC_chan_rel_rll_rel_ind pass, see also OS#2730
This commit has been tested using the BSC_Tests TTCN3 testsuit and the
following tests were passed:
TC_chan_act_noreply
TC_chan_act_ack_noest
TC_chan_act_ack_est_ind_noreply
TC_chan_act_ack_est_ind_refused
TC_chan_act_nack
TC_chan_exhaustion
TC_ctrl
TC_chan_rel_conn_fail
TC_chan_rel_hard_clear
TC_chan_rel_hard_rlsd
TC_chan_rel_a_reset
TC_rll_est_ind_inact_lchan
TC_rll_est_ind_inval_sapi1
TC_rll_est_ind_inval_sapi3
TC_rll_est_ind_inval_sacch
TC_assignment_cic_only
TC_assignment_csd
TC_assignment_ctm
TC_assignment_fr_a5_0
TC_assignment_fr_a5_1_codec_missing
TC_assignment_fr_a5_1
TC_assignment_fr_a5_3
TC_assignment_fr_a5_4
TC_paging_imsi_nochan
TC_paging_tmsi_nochan
TC_paging_tmsi_any
TC_paging_tmsi_sdcch
TC_paging_tmsi_tch_f
TC_paging_tmsi_tch_hf
TC_paging_imsi_nochan_cgi
TC_paging_imsi_nochan_lac_ci
TC_paging_imsi_nochan_ci
TC_paging_imsi_nochan_lai
TC_paging_imsi_nochan_lac
TC_paging_imsi_nochan_all
TC_paging_imsi_nochan_plmn_lac_rnc
TC_paging_imsi_nochan_rnc
TC_paging_imsi_nochan_lac_rnc
TC_paging_imsi_nochan_lacs
TC_paging_imsi_nochan_lacs_empty
TC_paging_imsi_a_reset
TC_paging_counter
TC_rsl_drop_counter
TC_classmark
TC_unsol_ass_fail
TC_unsol_ass_compl
TC_unsol_ho_fail
TC_err_82_short_msg
TC_ho_int
Authors:
Harald Welte <laforge@gnumonks.org>
Philipp Maier <pmaier@sysmocom.de>
Neels Hofmeyr <neels@hofmeyr.de>
Closes: OS#2730
Closes: OS#2731
Closes: OS#2762
Closes: OS#2768
Closes: OS#2775
Closes: OS#2823
Closes: OS#2898
Closes: OS#2936
Change-Id: I68286d26e2014048b054f39ef29c35fef420cc97
Pau Espin
Neels Hofmeyr
Harald Welte
Philipp Maier