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Get rid of the legacy name bscconfig.h from osmo-nitb times.
Remove the #include from some of the files that aren't actually using it.
Instead of '#include "../../config.h"', use plain '#include "config.h"'
because we're anyway passing $top_srcdir as -I during compilation.
Change-Id: Id4f683be1f36f0630c83da54e02868aae847aeec
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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
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Pass trans around more functions as log context.
Add missing "rx" logging for two cases.
Change-Id: If79f724a2faca70023271398c618cfe490fb294e
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Change-Id: I2e60964d7a3c06d051debd1c707051a0eb3101ba
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Depends: Ife31e6798b4e728a23913179e346552a7dd338c0 (libosmocore)
Change-Id: Ib06d030e8464abe415ff597d462ed40eeddef475
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Change-Id: I2d3a6334f49989bedbb1430d26ffad8b61dfd873
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According to GSM 04.07, the TI flag takes one bit and can be
either of the following:
'0'B - transaction is allocated by sender of a message,
'1'B - transaction is allocated by receiver of a message.
Since we store transaction ID in gsm_trans structure, we also store
TI flag (as a part of transaction ID), which in this context means:
'0'B - transaction is allocated by us (OsmoMSC),
'1'B - transaction is allocated by some MS.
In 100% cases, trans_assign_trans_id() is used to assign transaction IDs
to transactions allocated by us (i.e. OsmoMSC) for MT connections. And
there is no need to use it for MO transactions, because they basically
already do contain a valid transaction ID assigned by the MS.
Change-Id: Ie11999900b1789652ee078d34636dcda1e137eb0
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Add an SGs interface (3GPP TS 29.118) to osmo-msc in order to support
SMS tunneling and Circuit Switched Fallback (CSFB)
Change-Id: I73359925fc1ca72b33a1466e6ac41307f2f0b11d
Related: OS#3615
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Log transaction allocation errors as such. While at it, use proper
subsystem to log missing VLR subscriber.
Change-Id: I617be8793b9416ccd49022c72f7d93df7f4fb4d9
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Change-Id: Icbf099e418281eb908e7916503f178ab7ea26ffe
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Various places in the code check a flag whether assignment was started and
launch it. To fix incoming-call-during-ongoing-call, I will tweak that logic.
To be able to do that only in one place, remove code dup.
Cosmetic preparation for I1f8746e7babfcd3028a4d2c0ba260c608c686c76 and
I0ba216b737909e92080a722db26e3577726c63cb/
Depends: I11b182a03f5ecb6df7cd8f260757d3626c8e945d (libosmocore: LOGPFSMSL)
Change-Id: I11c0b7dc3f1a747028629b48e522bb3b864884ba
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Always use LAC which is part of Cell Global ID otherwise we might end up
in a situation where separately stored LAC differs.
Both are described in 3GPP TS 23.008 $2.4 as temporary subscriber data
to be stored in VLR. Both are defined in 3GPP TS 23.003. The LAC is part
of LAI which is part of CGI so there should be no case when those values
differ for a given subscriber.
Change-Id: I993ebc3e14f25e83124b6d3f8461a4b18f971f8e
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Change-Id: I6e2efcd2e25d6ec2ff35a4b8cfcda02abe97fa59
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Change-Id: I8e0febd04f7338aed7222dcfcd9bfddc7b8fda59
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For hysterical raisins, there are some header files that contain few
declarations, and where the name doesn't reflect the content. Combine them to
new msc_common.h:
- common.h
- common_cs.h
- osmo_msc.h
Change-Id: I9e3a587342f8d398fb27354a2f2475f8797cdb28
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Following previous rename of gsm_subscriber_connection:
Some functions and #defines are still called like "msc_conn" or just "msc_",
while they are clearly about a RAN conn.
To avoid confusion with the future separate concepts of MSC roles and a RAN
connection, rename all those to match the common "ran_conn" prefix.
Change-Id: Ia17a0a35f11911e00e19cafb5d7828d729a69640
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In preparation for inter-BSC and inter-MSC handover, we need to separate the
subscriber management logic from the actual RAN connections. What better time
to finally rename gsm_subscriber_connection.
* Name choice:
In 2G, this is a connection to the BSS, but even though 3GPP TS commonly talk
of "BSS-A" and "BSS-B" when explaining handover, it's not good to call it
"bss_conn": in 3G a BSS is called RNS, IIUC.
The overall term for 2G (GERAN) and 3G (UTRAN) is RAN: Radio Access Network.
* Rationale:
A subscriber in the MSC so far has only one RAN connection, but e.g. for
inter-BSC handover, a second one needs to be created to handover to. Most of
the items in the former gsm_subscriber_connection are actually related to the
RAN, with only a few MM and RTP related items. So, as a first step, just rename
it to ran_conn, to cosmetically prepare for moving the not strictly RAN related
items away later.
Also:
- Rename some functions from msc_subscr_conn_* to ran_conn_*
- Rename "Subscr_Conn" FSM instance name to "RAN_conn"
- Rename SUBSCR_CONN_* to RAN_CONN_*
Change-Id: Ic595f7a558d3553c067f77dc67543ab59659707a
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Change-Id: I322dc18cfe2cc573744261df837e719b5cf224ba
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The external MNCC handler may hang indefinitely in cases where the remote
end of the MNCC ceases to work properly. Add a global guard timer to
make sure the call reaches ACTIVE state.
Change-Id: I7375d1e17cd746aac4eadfe1e587e82cf1630d3d
Related: OS#3599
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At the moment osmo-msc populates the member ip in struct gsm_mncc_rtp
with the wrong byte ordering. This causes LCR or
osmo-sip-connector to receive the IP address in the wrong order, which
eventually leads into a reversed IP address in the SDP part of the SIP
messages.
Change-Id: I86148179b549b511528e4c65213eb6c204cc609e
Related: OS#3431
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When the assignment completes a choosen codec is returned. At the
moment we do not use this information.
- add struct members for codec info (both, RAN and CN)
- parse codec info in BSSMAP ASSIGNMENT COMPLETE
- use codec info on mgcp
Since the MNCC API is not complete yet, we currently only use the
codec info only on the internal MNCC yet.
Change-Id: I9d5b1cd016d9a058b22a367d0e5e9f2ef447931a
Related: OS#2728
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The CC sub-layer is fairly self-contained, so let's move it to
a separate C source file. The old gsm_04_08.c file now only
contains the 04.07 / DTAP core and MM sub-layer handling.
I did this initially as an experiment to see how self-contained
our CC implementation really is. Given this rather straight-forward
patch builds fine, CC really is self-contained (yay!).
Change-Id: Idb8dd7a8d9d8b4a28c492f12da3cc3305b695cca
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