This change implements an additional channel allocation mode, which
can be employed during a TCH channel allocation for assignment.
Selection between ascending and descending order is performed
depending on pre-configured parameters:
* Uplink RxLev threshold and number of samples for averaging,
* C0 (BCCH carrier) channel load threshold.
This is useful in setups where Tx power of the RF carriers cannot be
adjusted +dynamically at run-time and thus BS Power Control cannot
be performed. In such setups the BCCH carrier is transmitting at
relatively higher power than the other RF carriers. The key idea
is to allocate channels in a smarter way, so that UEs with poor signal
would get channels on carriers with high Tx power, while UEs with good
signal could use carriers with lower Tx power.
Change-Id: I1b7a0d706976b73cc5c30a8714b830811addfe8d
Related: osmo-ttcn3-hacks.git Ia522f37c1c001b3a36f5145b8875fbb88311c2e5
Related: SYS#5460
A follow-up patch implements a special channel allocation mode, which is
only working for assignment (basically TCH selection for a voice call).
This mode cannot be employed for initial CHANNEL REQUEST or handover due
to the absence of an already established lchan.
Adding this mode to the existing VTY command syntax would be confusing:
channel allocator (ascending|desscending|dynamic)
^^^^^^^
so this patch extends the VTY syntax in a way that it becomes possible
to configure different channel allocator modes for different cases:
OsmoBSC(config-net-bts)# channel allocator mode ?
set-all Set a single mode for all variants
chan-req Channel allocation for CHANNEL REQUEST (RACH)
assignment Channel allocation for assignment
handover Channel allocation for handover
The old command syntax, which is basically 'set-all', is kept for
backwards compatibility, but marked as deprecated.
Change-Id: I3ae73b36ee9433cc768376b56f0765e5f416162f
Related: SYS#5460
Add missing conn->assignment.created_ci_for_msc to
gscon_forget_mgw_endpoint_ci().
Before this patch, when assignment.created_ci_for_msc lingers after a
DLCX, it can cause a use-after-free on assignment_reset(). Possible
scenario is rx BSSMAP Clear Cmd during ongoing Assignment.
In assignment_reset(), locally cache the ci pointer, because
gscon_forget_mgw_endpoint_ci() now NULLs created_ci_for_msc.
Related: OS#5572
Change-Id: If89610020f47fd6517081dd11b83911b043bd0f1
When the assignment succeeds, the assignment_request has taken effect
and whatever it requested should now be in effect.
Hence copy the new RTP information from the assignment_request to the
conn's storage indicating what is currently used, always, not only when
lchan_changed == true. The RTP information may have changed also from a
Mode Modify where the lchan stays the same but changes its mode of use,
e.g. from signalling to voice.
When there is no RTP involved, this data is zero or empty, so there is
no harm in copying it, always.
Related: SYS#5916
Change-Id: I0788d1f013b8f820f559b6ed58a5f9bb8a02e0b4
When the assignment fails, we roll back the MSC side RTP endpoint at the
MGW that may have been created before the failure occured. On success,
we clear the mgcp_ci pointer so it is not rolled back.
Always clear this, not only when lchan_changed == true. That is because
a channel Mode Modify may also have added a voice stream that should
retain the newly created RTP endpoint at the MGW.
If no voice stream is involved, the pointer should already be NULL.
There is no reason to have a condition for clearing this pointer.
Just always clear it.
This fixes all voice calls that modify a TCH lchan from signalling-only
to voice mode. Before this patch, their MSC side RTP endpoint was DLCX'd
right on assignment success.
In particular, this fixes Emergency Calls (which usually get a TCH lchan
assigned right from the start, and hence do a Mode Modify to add voice).
Related: SYS#5916
Change-Id: I5ab10ee7fd9c5d7608e8a06893881d990943feed
I find it weird that we store the A5 algorithm ID in a format that
is used on the wire: N + 1 (valid for both A-bis and A interfaces).
What confused me even more is that in some functions we print it
as if it was in a normal, human-readable format. And this is
also why one can see weird constructions like:
if (lchan->encr.alg_id > ALG_A5_NR_TO_RSL(0)) { ... }
Let's ensure that our internal structures use the A5/N format:
alg_id=0: A5/0 (0x01 on the A-bis/A interface)
alg_id=1: A5/1 (0x02 on the A-bis/A interface)
alg_id=2: A5/2 (0x03 on the A-bis/A interface)
...
alg_id=7: A5/7 (0x08 on the A-bis/A interface)
so that we can print and compare the value of alg_id without using
additional arithmetics. Let's also rename 'alg_id' to 'alg_a5_n'
as it most clearly indicates which representation it is storing.
This is how the above code snippet would look like:
if (lchan->encr.alg_a5_n > 0) { ... }
Change-Id: Ieb50c9a352cfa5481aebac2379e0a461663543ec
Counting the Assignment success after osmo_fsm_inst_term() meant that we
were counting a cleared out channel mode, which always yielded
signalling mode.
Count the Assignment success *before* terminating, so that we correctly
count the successful assignment as speech mode.
Related: SYS#4878
Related: Icb1386ec2ccd70eb3c026301b9b08ad7177278f7 (osmo-ttcn3-hacks)
Change-Id: Ie9fcd1e86f27ecb2f11e2e8813faac365cb470b8
From the nature of the lchan_activate_info.tsc_set and .tsc, it is easy
to forget to set tsc_set,tsc = -1 to use default TSC Set and TSC values.
Handover code is one such instance that forgets to set -1.
Change the semantics of tsc_set and tsc so that this kind of error can
not happen again as easily: use a separate bool to flag whether to use
the default config or explicit values.
Implicitly fix the lchan_activate_infos "launched" in handover_fsm.c as
well as abis_rsl_chan_rqd_queue_poll().
Related: OS#5244 SYS#4895
Related: I1ed6f068c85b01e5a2d7b5f2651498a1521f89af (osmo-ttcn3-hacks)
Change-Id: Iae20df4387c3d75752301bd5daeeea7508966393
When the SDCCH gets released while the TCH still beeing activated, then
the ChanActivACK that is received after the TCH is activated will trigger
a segmentation fault in the assignment_fsm. The reason for this is that
conn->lchan, which holds the SDCCH at that point in time, is now NULL.
To prevent osmo-bsc from crashing, the FSM should check for the presence
of conn->lchan first. If it does not exist, the FSM should terminate.
(Assignment failed)
Change-Id: I3b1cd88bea62ef0032f6c035bac95d3df9fdca7a
Related: SYS#5627
assignment_fsm_allstate_action is only used in module assignment_fsm.c,
so lets decalare it as static
Change-Id: I90d6c11bd485e3be80efc7f146e0129d93e18458
Instead of having static const structs in header files (which end up
duplicated in each and every compile unit!), have one .c file with the
rate_ctr and stat_item descriptions.
Related: SYS#5542
Change-Id: I8fd6380b5ae8ed2d3347e7cfbf674c30b6841ed9
Let's make sure the null pointer is caught by the assert if ever code
ends up here with conn->lchan being NULL.
Change-Id: I404df638da6a93caa535f10fd330ea24a775bfc3
Drop terminating newline from an assignment_fail() call which causes an
erratic line feed in logging.
Change-Id: Ib56e1f6a45c7e2c235f8ef0c8dea7151481677ab
Change gsm_lchan_name_compute() to a function that in-place updates the
lchan->name. That allows calling it numerous times with the talloc
handled internally. Rename it to lchan_update_name().
Add 'shadow' to lchan_update_name() and lchan_fsm_update_id() for VAMOS
shadow lchans, and also print the lchan index that it is a shadow for,
instead of the index in the lchan array.
When set_pchan_is() updates the VAMOSness of the lchans, call
lchan_fsm_update_id(). From lchan_fsm_update_id() also call
lchan_update_name().
This is a bit convoluted for legacy reasons. There are utility programs
and C tests using bts_trx.c but not lchan_fsm.c. lchan_update_name()
lives in gsm_data.c for that reason. This patch calls
lchan_update_name() from lchan_fsm_update_id() and not vice versa to
avoid having to add stubbed lchan_fsm_update_id() functions to all
utility programs and C tests.
We can't easily unify the lchan->name and lchan->fi->id without lots of
refactoring rippling through all those little utility programs and C
tests.
Change-Id: I7c2bae3b895a91f1b99b4147ecc0e3009cb7439a
So far there is a bunch of code setting a primary lchan in VAMOS mode.
This patch now adds the actual secondary "shadow" lchans that may be
combined with a primary lchan in VAMOS mode to form a multiplex.
VAMOS lchans are put in the same ts->lchan[] array that keeps the
primary lchans. They are at most two additional usable lchans (for a
TCH/H shadow) added to either TCH/F or TCH/H.
Keeping these in the same array allows looping over all lchans easily.
The ts->max_primary_lchans indicates the index of the first VAMOS shadow
lchan.
Related: SYS#5315 OS#4940
Change-Id: I928af99498bba488d317693f3144d4fccbbe9af3
lchan->activate.info.ch_mode_rate should remain unchanged, it is the
immutable request data. However, for VAMOS, we will want to
automatically see that the chan_mode is chosen correctly.
As a first step, place a mutable ch_mode_rate copy at
lchan->activate.ch_mode_rate, i.e. not in .activate.info, but in
.activate. Use that everywhere.
This is mostly a non-functional change, preparing for a subsequent patch
that adds handling of VAMOS shadow lchans.
As side effect of adding lchan_activate_set_ch_mode_rate_and_mr_config()
after MODE_MODIF_ACK (enabling the voice stream after a channel mode
modify), fix AMR config: the call to lchan_mr_config() was missing.
Change-Id: Icc9cc7481b3984fdca34eef49ea91ad3388c06fe
An unintended change in default behavior was introduced in patch:
"allow explixit TSC Set and TSC on chan activ / modif / assignment"
Ic665125255d7354f5499d10dda1dd866ab243d24
c33eb8d569
Set tsc_set and tsc = -1 for all lchan_activate_info and
assignment_request requests to actually yield the default behavior of
selecting the TSC based on the timeslot cfg or the BSIC value.
By setting tsc = 0 implicitly, the patch caused all requests to ask for
tsc 0 instead of calling gsm_ts_tsc().
For a Channel Mode Modify in assignment_fsm, pass the lchan's current
TSC to keep it unchanged.
osmo-ttcn3-hacks Id67a949e0f61ec8123976eb8d336f04510c55c01 adds a test
to verify the expected TSC in all of the activation, assignment and
modify messages. Current osmo-bsc master fails, this patch fixes.
Related: SYS#5315 OS#4940 Ic665125255d7354f5499d10dda1dd866ab243d24
Change-Id: If12df11511fe22ea167782f776736a1a9c484b1f
Both VAMOS- and non-VAMOS speech modes should result in indentical voice
handling. So make sure that all chan_modes are converted to non-vamos
before comparing / evaluating in switch statements.
Change-Id: I791e7966b1f8eaa3299a8a46abeb313cf5136e0b
Activating / modifying to a VAMOS mode will require picking specific TSC
Set / TSC. It is a bad idea to pick the TSC in each message encoding
function, rather make this choice centrally.
So far we pick the training sequence code to use based on the timeslot
configuration, and this TSC is determined only upon encoding the RSL
messages.
Instead, pick the TSC to use upon the initial lchan activation /
modification request; store this in the request structs and pass through
the activation / modification code paths.
For VAMOS modes, we also need to pick a TSC Set. Do so also upon activ /
modif request. Note that the TSC Set is not yet applied in this patch,
it will be applied in upcoming VAMOS patches.
The activ / modif request may pass -1 for tsc_set and/or tsc to indicate
no specific choice of TSC Set and TSC, resulting in the same behavior as
before this patch.
For example, lchan->activate.info.tsc* may be passed as -1. The exact
choice for tsc_set and tsc is then stored in lchan->activate.tsc*, i.e.
one level up (the .info sub-struct is considered as immutable input
args). The lchan->activate.tsc* are the values actually encoded in RSL
messages. After the ACK, the lchan->activate.tsc* is stored in
lchan->tsc* to indicate the TSC actually in use. Same for modif.
Note that in 3GPP TS 45.002, the TSC Set are numbered 1 to 4, while the
TSC are numbered 0 to 7. On the wire, though, TSC Set is sent as 0 to 3
value. This is a weird discrepancy, odd choice made by the spec authors.
For conformance with the spec wording, I decided to pass the TSC Set
number as a 1-4 ranged value, and only convert it to the 0-3 on-the-wire
format upon message encoding. So log messages and VTY output will
indicate the first TSC Set as "1", but the first TSC as "0", as defined
in 3GPP TS 45.002, even if that is somewhat weird.
Related: SYS#5315 OS#4940
Change-Id: Ic665125255d7354f5499d10dda1dd866ab243d24
So far the assignment FSM always tried to satisfy the channel mode and
rate by either re-using the current lchan or finding a new, unused
lchan. For VAMOS however, we want to pick one specific lchan.
Add target_lchan to struct assignment_request and skip all mode matching
and lchan selection when a specific target_lchan is set.
Related: SYS#5315 OS#4940
Change-Id: I71e0d4ff4746706e0be5266e4574d70ca432e3d7
It is better design to take state change actions in the onenter
function, instead of triggering a state change and then calling
lchan_mode_modify() or lchan_activate(). The reason is that in
principle, any state change may cause error handling to abort and
deallocate FSMs.
This is also preparation for reassignment to a specific lchan in an
upcoming patch.
Related: SYS#5315 OS#4940 OS#3277
Change-Id: I9a2e7eefd4196b80671311e5dfd275893ec0e275
The single place that calls this special case is now actually doing the
exact same thing as the general case, and this is merely code dup.
Related: SYS#5315 OS#4940
Change-Id: Ic62e8a48d3c88a1966086240a41732d169328491
I noticed during testing that an lchan used as TCH/F in fact still had
its channel mode set to Signalling -- because on Assignment, the Speech
mode used to be placed in the *previous* lchan and the new lchan was
never updated after the Activ ACK. This is unbearable confusion which I
complained about numerous times, so far mostly for cosmetic reasons. But
implementing re-assignment properly actually requires this to be cleaned
up.
Keep all volatile chan mode settings in lchan->activate.* or
lchan->modify.*, and only update lchan->* members when an ACK has been
received for those settings. So a failed request keeps a sane state.
Make sure that those settings are in fact updated in the proper lchan,
upon an ACK, so that subsequent re-assignment or mode-modify know the
accurate lchan state.
Related are upcoming patches that sort out the AMR multirate
configuration in a similar fashion, see
Iebac2dc26412d877e5364f90d6f2ed7a7952351e
Ia7519d2fa9e7f0b61b222d27d077bde4660c40b9
Ie57f9d0e3912632903d9740291225bfd1634ed47.
Related: SYS#5315 OS#4940 OS#3787 OS#3833
Change-Id: Ie0da36124d73efc28a8809b63d7c96e2167fc412
So far, only the MSC asked for Assignment via Assignment Request, which
we answer with a BSSMAP Assignment Complete or Assignment Failure when
done.
When Assignment is triggered for any other reason (congestion
resolution, VAMOS, VTY), we will not send any such messages to the MSC.
Additional enum values will be added in subsequent commits:
Id56a890106b93fcee67ac9401b890e7b63bba421 ASSIGN_FOR_CONGESTION_RESOLUTION
If006f5caaf83b07675f57e5665cfa79328da55e6 ASSIGN_FOR_VTY
Related: SYS#5315 OS#4940
Change-Id: Ie0cddbdb00abcec78e153f4ae6d04ce75080a111
The Channel Mode Modify procedure is currently implemented for changing
a TCH lchan from signalling to voice mode. For that, however, it is
re-using (abusing) the channel activation structs and state transitions,
and thus always implies activating a voice stream when the mode
modification is done.
I will add a Channel Mode Modify to enable VAMOS mode soon, so I require
separate structs and state transitions which also work on an lchan that
already has a voice stream established: a struct lchan_modify_info and
LCHAN_EV_REQUEST_MODE_MODIFY, and dedicated assignment FSM state
ASSIGNMENT_ST_WAIT_LCHAN_MODIFIED.
For the part where a Channel Mode Modify enables a voice stream after
switching from signalling to speech mode, still use the channel
activation code path, but only once the mode modification is done.
General improvements:
- To ask for a mode modification, emit an FSM event that ensures a mode
modify only happens when the lchan state allows it.
- The new lchan_modify_info struct reflects only those parts that have
an effect during a mode modification (before the lchan_activate_info
was fully populated, many values not having an effect).
- More accurate logging, indicating "Mode Modify" instead of "Channel
Activation"
A TTCN3 test for the Channel Mode Modify procedure is added in
Idf4efaed986de0bbd2b663313e837352cc139f0f, and the test passes both
before and after this patch is applied.
Related: SYS#4895
Change-Id: I4986844f839b1c9672c61d916eb3d33d0042d747
Soon, there will also be enums with ASSIGNMENT_FOR_* and MODIFY_FOR_*
naming. Add the ACTIVATE_ prefix to the existing enum to clarify.
Change-Id: I12190d4d154a1da6a9ebc9a755ccc2fe382ff188
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
On lchan activation, we already know the Timing Advance in most
situations: from the Channel Request RACH, or from a previous lchan in
the same cell. Place this information in lchan->activate.info.ta.
So far, the lchan->last_ta (until recently called rqd_ta) was used to
store the initial TA for channel activation -- move the initial TA to
lchan->activate.info.ta, for proper scoping.
Only an inter-cell handover does not yet know a Timing Advance (until
the Handover Detection RACH is received), so indicate
activate.info.ta_known = false for that case.
If ta_known is false, do not include an Access Delay IE in the Channel
Activation message, ensuring that the BTS does not use an arbitrary TA
that is likely inaccurate.
The effect for OsmoBTS is that we will *not* start the downlink SACCH on
channel activation for inter-cell handover, but will wait for a HO RACH
first, and then use the correct TA when enabling downlink SACCH.
Related: OS#4008 SYS#5192
Change-Id: I986bf93e8acd6aef7eaf63ac962480b680aa894f
This is a non-standard RSL message that must be sent after each traffic
channel has been established. Without it, any voice call will be
disconnected within seconds.
This is a hack; we need to store the subscribers classmark2 value and
use it here.
Change-Id: I6cb6d25e405aa888c4df4022d897330a6af9e946
Related: OS#2389
osmo-nitb supports the modification of an lchan if the lchan is
compatible but in the wrong mode. This feature was dropped in the
transition to AoIP/bsc-split. However, osmo-bsc still has code to
generate and parse the messeages, but the FSMs do not support a mode
modify yetm
Lets add handling for mode-modify to the lchan_fsm and assignment_fsm in
order to support mode modify again
Change-Id: I2c5a283b1ee33745cc1fcfcc09a0f9382224e2eb
Related: OS#4549
Place all code related to the object into the related file.
Having all the data model in one file made sense in early stage of
development to make progress quickly, but nowadays it hurts more than
helps, due to constantly growing size and more and more bits being
added to the model, gaining in complexity.
Currently, having lots of different objects mixed up in gsm_data.h is a hole
of despair, where nobody can make any sense were to properly put new stuff
in, ending up with functions related to same object in different files
or with wrong prefixes, declarations of non-existing functions, etc.
because people cannot make up their mind on strict relation to objects
in the data model.
Splitting them in files really helps finding code operating on a
specific object and helping with logically splitting in the future.
Change-Id: I00c15f5285b5c1a0109279b7ab192d5467a04ece
Starting from ttcn3-bsc-test-sccplite build #777, it was noticed
that osmo-bsc crashes with the following message:
Assert failed conn->lchan include/osmocom/bsc/gsm_data.h:1376
The cause of this is a recently merged patch that calls conn_get_bts() during
assignment_fsm rate counter dispatch:
"Count assignment rates per BTS as well"
commit b5ccf09fc4
Change-Id I0009e51d4caf68e762138d98e2e23d49acc3cc1a
The root cause being that the assignment_fsm attempts to count an Assignment
event for a BTS after the lchan has already been released and disassociated
from the conn.
The assertion is found in conn_get_bts(), which is used in various places. In
fact, each caller is a potential DoS risk -- though most are in code paths that
are guaranteed to have an lchan and bts present, having an OSMO_ASSERT() on the
relatively volatile presence of an lchan is not a good idea for osmo-bsc's
stability and error resilience.
- Change conn_get_bts() to return NULL in the lack of an lchan.
- Adjust all callers of conn_get_bts() to gracefully handle a NULL return val.
- Same for cgi_for_msc() and callers, closely related.
Here is a backtrace:
Program received signal SIGABRT
pwndbg> bt
0x0000555555be6e52 in conn_get_bts (conn=0x622000057160) at include/osmocom/bsc/gsm_data.h:1376
0x0000555555c1edc8 in assignment_fsm_timer_cb (fi=0x612000060220) at assignment_fsm.c:758
0x00007ffff72b1104 in fsm_tmr_cb (data=0x612000060220) at libosmocore/src/fsm.c:325
0x00007ffff72ab062 in osmo_timers_update () at libosmocore/src/timer.c:257
0x00007ffff72ab5d2 in _osmo_select_main (polling=0) at libosmocore/src/select.c:260
0x00007ffff72abd2f in osmo_select_main_ctx (polling=<optimized out>) at libosmocore/src/select.c:291
0x0000555555e1b81b in main (argc=3, argv=0x7fffffffe1b8) at osmo_bsc_main.c:953
0x00007ffff6752002 in __libc_start_main () from /usr/lib/libc.so.6
0x0000555555b61bbe in _start ()
In the case of the assignment_fsm counter, we now miss a chance to increase a
BTS counter for a failed Assignment, but this is a separate problem. The main
point of this patch is that osmo-bsc must not crash.
Related: OS#4620, OS#4619
Patch-by: fixeria
Tweaked-by: neels
Fixes: I0009e51d4caf68e762138d98e2e23d49acc3cc1a
Change-Id: Id681dfb0ad654bdb4b71805d1ad4f39a8bf6bbd1
This adds the assignment counters for the BTS as well and changes the
assignment_count() macro to increase both the counters for the BSC as
well as the BTS.
Related: SYS#4877
Change-Id: I0009e51d4caf68e762138d98e2e23d49acc3cc1a
We already have counters for Rx side, now we also count Tx side.
See comments in the msc_ctr_description array implementation for
the details.
Change-Id: I89a173f6bdd9a3c21233fe01d07ab2ff0442bb10
Vadim Yanitskiy
Neels Hofmeyr
Pau Espin
Philipp Maier
Neels Hofmeyr
Harald Welte
Daniel Willmann