Commit Graph

13 Commits

Author SHA1 Message Date
Neels Hofmeyr 27c07690d9 replace ts_*_for_each_lchan() with ts_for_n_lchans()
So far we have a couple of macros iterating a specific number of lchans,
depending on dynamic timeslot state etc. With addition of VAMOS lchans,
this would become more complex and bloated.

Instead of separate iteration macros for each situation, only have one
that takes a number of lchans as argument. That allows to more clearly
pick the number of lchans, especially for non-trivial VAMOS scenarios.

Related: SYS#5315 OS#4940
Change-Id: Ib2c6baf73a81ba371143ba5adc912aef6f79238d
2021-05-31 05:20:03 +00:00
Neels Hofmeyr 764449ec2e fix/refactor neighbor config
The neighbor configuration storage is fundamentally broken: it requires
all local cells to be configured before being able to list them as
neighbors of each other. Upon config write-back, the neighbor config
however is placed back inline with the other config, and hence a
written-out neighbor config no longer works on program restart.

The cause of this problem is that the config is stored as explicit
pointers between local cells (struct gsm_bts), which of course requires
the pointer to exist before being able to reference it.

Instead, store the actual configuration that the user entered as-is,
without pointers or references to objects that need to be ready. Resolve
the neighbors every time a neighbor is needed.

Hence the user may enter any config at any place in the config file,
even non-working config (like a BTS number that doesn't exist), and the
relation to actual local or remote neighbor cells is made at runtime.

Abort program startup if the initial neighbor configuration contains
errors.

Related: OS#5018
Change-Id: I9ed992f8bfff888b3933733c0576f92d50f2625b
2021-03-24 21:22:21 +01:00
Pau Espin Pedrol a27e8a5c9a Move bts_ident_key to neighbor_ident.c
The function is not really handover specific, and will be used in other
places in subsequent patches.

Change-Id: Icae8b9045e497f850f22cb3b6f93acbf61b84746
2021-02-13 08:15:01 +00:00
Neels Hofmeyr 4d26688239 handover: fix detection for ambiguous HO neighbor ident
Adding rate counter checks to TC_ho_neighbor_config_1 (1.c) uncovers that the
test passes for the wrong reason. The ambiguous cell identification should be
the cause for the handover error, but the log shows that instead a handover is
attempted to BTS 3 which is not connected.

find_handover_target_cell() first tries to find a precise match of values, and
in a second pass applies wildcards like BSIC_ANY and
NEIGHBOR_IDENT_KEY_ANY_BTS. That second pass lacks detection of ambiguous
matches.

Use the same code for both passes, by encapsulating in a loop of two, which
first runs with exact_match == true and then false.

Proper detection of the ambiguous target cell identification in
TC_ho_neighbor_config_1() is shown by the resulting 'handover:error' count,
see I10bc0b67ca8dcf41dbb02332ed18017e819c2b32 (osmo-ttcn3-hacks).

Related: OS#4736
Related: I10bc0b67ca8dcf41dbb02332ed18017e819c2b32 (osmo-ttcn3-hacks)
Change-Id: Ib0087b6566ae4d82f8c3ef272c1256bcd1d08bf1
2020-08-31 18:01:17 +02:00
Pau Espin 388ed58482 Move struct gsm_bts: gsm_data.* => bts.*
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
2020-07-18 21:45:32 +00:00
Neels Hofmeyr 91a202d488 neighbor config: allow re-using ARFCN+BSIC pairs
Fix neighbor config to match OsmoBSC manual: implement the plan for neighbor
configuration that was so far only described in the manual without actually
being in operation.

This first allows re-using ARFCN+BSIC pairs in and across BSS.

So far the handover_start() code always looked for handover target cells across
*all* local cells, even if they were not listed as neighbors to a source cell.
Imply all cells as neighbors only as long as there are no explicit neighbors
configured. As soon as the first 'neighbor' line appears in a 'bts' config,
only the listed neighbors are regarded as handover target cells. (The
'neighbor-list' commands are not related to this, only the relatively new
'neighbor (bts|lac|cgi|...)' commands affect actual handover procedures.)

TTCN3 tests TC_ho_neighbor_config_1 thru _7 play through the various aspects of
neighbor configuration: both the legacy implicit all-cells-are-neighbors as
well as allowing only explicit neighbors by config.

Related: OS#4056
Related: osmo-ttcn3-hacks Ia4ba0e75abd3d45a3422b2525e5f938cdc5a04cc
Change-Id: I29bca59ab232eddc74e0d4698efb9c9992443983
2019-08-13 23:47:23 +02:00
Neels Hofmeyr 31f525e756 large refactoring: use FSMs for lchans; add inter-BSC HO
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
2018-07-28 12:18:23 +02:00
Neels Hofmeyr 6242742d20 rename gsm_04_08_utils.[hc] to gsm_04_08_rr
"utils" suggests thin helpers to aid using a proper API, while this .c file
actually *is* the proper RR API. Rename from "utils" to "rr".

Change-Id: I0ffff63d57f03cb324df8e40e41caea5b55a2c85
2018-07-28 12:18:23 +02:00
Neels Hofmeyr 431e085736 inter-BSC HO: neighbor_ident API: drop 9bit BSIC
9-bit BSIC exist in the 3GPP specs, but we don't use them anywhere. Rather
remove that choice from the API and UI.

Change-Id: I29b92f47da2636d3a19f073755f9382fa98f9010
2018-07-28 12:18:23 +02:00
Neels Hofmeyr 19bed23065 inter-BSC HO: add neighbor_ident API to manage neighbor-BSS-cells
Depends: Ia71ba742108b5ff020997bfb612ad5eb30d04fcd (libosmocore)
Change-Id: I0153d7069817fba9146ddc11214de2757d7d37bf
2018-07-28 12:18:23 +02:00
Neels Hofmeyr 31716f981a hodec2 log: less verbose, more concise logging
Drop numerous log statements that merely bloat the ho decision log.

Logging HO candidates: log more compact in a single line, do not use LOGPC and
multiline output. The result is more useful information in a quarter of the log
lines.

LOGPHOLCHAN(), LOGPHOLCHANTOBTS():
- log lchan->type instead of lchan->ts->pchan
- always log the speech mode

===== Before =====

DHODEC handover_decision_2.c:1131 (lchan 0.010 TCH/F) (subscr IMSI:000001) MEASUREMENT REPORT (1 neighbors)
DHODEC handover_decision_2.c:1136 (lchan 0.010 TCH/F) (subscr IMSI:000001)   0: arfcn=871 bsic=63 neigh_idx=0 rxlev=30 flags=0
DHODEC handover_decision_2.c:261 (lchan 0.010 TCH/F) (subscr IMSI:000001) neigh 871 rxlev=30 last_seen_nr=3
DHODEC handover_decision_2.c:1158 (lchan 0.010 TCH/F) (subscr IMSI:000001) HODEC2: evaluating measurement report
DHODEC handover_decision_2.c:1175 (lchan 0.010 TCH/F) (subscr IMSI:000001) Measurement report: average RX level = -110
DHODEC handover_decision_2.c:1190 (lchan 0.010 TCH/F) (subscr IMSI:000001) Virtually improving RX level from -110 to -105, due to AFS bias
DHODEC handover_decision_2.c:1220 (lchan 0.010 TCH/F) (subscr IMSI:000001) Attempting handover/assignment due to low rxlev
DHODEC handover_decision_2.c:899 (lchan 0.010 TCH/F) (subscr IMSI:000001) Collecting candidates for Assignment and Handover
DHODEC handover_decision_2.c:407 (lchan 0.010 TCH/F)->(BTS 0) (subscr IMSI:000001) tch_mode='SPEECH_AMR' type='TCH_F'
DHODEC handover_decision_2.c:313 (lchan 0.010 TCH/F) (subscr IMSI:000001) FR3 supported
DHODEC handover_decision_2.c:313 (lchan 0.010 TCH/F) (subscr IMSI:000001) HR3 supported
DHODEC handover_decision_2.c:489 (lchan 0.010 TCH/F)->(BTS 0) (subscr IMSI:000001) removing TCH/F, already on TCH/F in this cell
DHODEC handover_decision_2.c:573 (lchan 0.010 TCH/F)->(BTS 0) (subscr IMSI:000001) TCH/H would not be congested after HO
DHODEC handover_decision_2.c:605 (lchan 0.010 TCH/F)->(BTS 0) (subscr IMSI:000001) TCH/H would not be less congested in target than source cell after HO
DHODEC handover_decision_2.c:609 (lchan 0.010 TCH/F)->(BTS 0) (subscr IMSI:000001) requirements=0x30
DHODEC handover_decision_2.c:704  - current BTS 0, RX level -110
DHODEC handover_decision_2.c:707    o free TCH/F slots 3, minimum required 0
DHODEC handover_decision_2.c:709    o free TCH/H slots 4, minimum required 0
DHODEC handover_decision_2.c:714    o no requirement fulfilled for TCHF (no assignment possible)
DHODEC handover_decision_2.c:737    o requirement A B fulfilled for TCHH (not congested after assignment)
DHODEC handover_decision_2.c:407 (lchan 0.010 TCH/F)->(BTS 1) (subscr IMSI:000001) tch_mode='SPEECH_AMR' type='TCH_F'
DHODEC handover_decision_2.c:313 (lchan 0.010 TCH/F) (subscr IMSI:000001) FR3 supported
DHODEC handover_decision_2.c:313 (lchan 0.010 TCH/F) (subscr IMSI:000001) HR3 supported
DHODEC handover_decision_2.c:563 (lchan 0.010 TCH/F)->(BTS 1) (subscr IMSI:000001) TCH/F would not be congested after HO
DHODEC handover_decision_2.c:573 (lchan 0.010 TCH/F)->(BTS 1) (subscr IMSI:000001) TCH/H would not be congested after HO
DHODEC handover_decision_2.c:595 (lchan 0.010 TCH/F)->(BTS 1) (subscr IMSI:000001) TCH/F would not be less congested in target than source cell after HO
DHODEC handover_decision_2.c:605 (lchan 0.010 TCH/F)->(BTS 1) (subscr IMSI:000001) TCH/H would not be less congested in target than source cell after HO
DHODEC handover_decision_2.c:609 (lchan 0.010 TCH/F)->(BTS 1) (subscr IMSI:000001) requirements=0x33
DHODEC handover_decision_2.c:701  - neighbor BTS 1, RX level -110 -> -80
DHODEC handover_decision_2.c:707    o free TCH/F slots 4, minimum required 0
DHODEC handover_decision_2.c:709    o free TCH/H slots 4, minimum required 0
DHODEC handover_decision_2.c:712    o requirement A B fulfilled for TCHF (not congested after handover)
DHODEC handover_decision_2.c:737    o requirement A B fulfilled for TCHH (not congested after handover)
DHODEC handover_decision_2.c:914 (lchan 0.010 TCH/F) (subscr IMSI:000001) adding 2 candidates from 1 neighbors, total 2
DHODEC handover_decision_2.c:1020 (lchan 0.010 TCH/F)->(BTS 1) (subscr IMSI:000001) Best candidate, RX level -80
DHODEC handover_decision_2.c:625 (lchan 0.010 TCH/F)->(BTS 1) (subscr IMSI:000001) Triggering Handover
DHODEC handover_decision_2.c:688 (lchan 0.010 TCH/F)->(BTS 1) (subscr IMSI:000001) Triggering handover to TCH/F, due to low rxlevel
DHO handover_logic.c:133 (BTS 0 trx 0 ts 1 lchan 0 TCH/F)->(BTS 1 lchan TCH_F) Initiating Handover...
DMSC handover_logic.c:135 SUBSCR_CONN[0x612000000520]{ACTIVE}: Received Event HO_START
DHODEC handover_logic.c:172 (BTS 0 trx 0 arfcn 870 ts 1 lchan 0 TCH/F)->(BTS 1 trx 0 arfcn 871 ts 1 lchan 0 TCH/F) (subscr IMSI:000001) Triggering Handover

===== After =====

DHODEC handover_decision_2.c:1039 (lchan 0.010 TCH_F SPEECH_AMR) (subscr IMSI:000001) MEASUREMENT REPORT (1 neighbors)
DHODEC handover_decision_2.c:1044 (lchan 0.010 TCH_F SPEECH_AMR) (subscr IMSI:000001)   0: arfcn=871 bsic=63 neigh_idx=0 rxlev=30 flags=0
DHODEC handover_decision_2.c:1097 (lchan 0.010 TCH_F SPEECH_AMR) (subscr IMSI:000001) Avg RX level = -110 dBm, +5 dBm AFS bias = -105 dBm; Avg RX quality = -1 (invalid), +0 AFS bias = -1
DHODEC handover_decision_2.c:1122 (lchan 0.010 TCH_F SPEECH_AMR) (subscr IMSI:000001) RX level is TOO LOW: -105 < -100
DHODEC handover_decision_2.c:677 (lchan 0.010 TCH_F SPEECH_AMR)->(BTS 0) (subscr IMSI:000001) RX level -110; TCH/F={free 3 (want 0), [-] not a candidate}; TCH/H={free 4 (want 0), [ABC] good}
DHODEC handover_decision_2.c:671 (lchan 0.010 TCH_F SPEECH_AMR)->(BTS 1) (subscr IMSI:000001) RX level -110 -> -80; TCH/F={free 4 (want 0), [ABC] good}; TCH/H={free 4 (want 0), [ABC] good}
DHODEC handover_decision_2.c:928 (lchan 0.010 TCH_F SPEECH_AMR)->(BTS 1) (subscr IMSI:000001) Best candidate, RX level -80
DHODEC handover_decision_2.c:641 (lchan 0.010 TCH_F SPEECH_AMR)->(BTS 1) (subscr IMSI:000001) Triggering handover to TCH/F, due to low rxlevel
DMSC handover_logic.c:125 SUBSCR_CONN[0x612000000520]{ACTIVE}: Received Event HO_START
DHODEC handover_logic.c:169 (BTS 0 trx 0 arfcn 870 ts 1 lchan 0 TCH_F SPEECH_AMR)->(BTS 1 trx 0 arfcn 871 ts 1 lchan 0 TCH/F) (subscr IMSI:000001) Triggering Handover

Change-Id: If1add9b57a051d32b67a4a08ab47a9655aa9dd17
2018-07-23 01:29:23 +02:00
Neels Hofmeyr bb7ea61725 fix handover start: dealloc ho if event not permitted
Before this, a handover request in a conn state that disallows it would leave a
lingering handover state in the conn, also thwarting any future handover
attempts. (It would be deallocated on conn teardown, so no memleak.)

Change-Id: I839a05495ae93c5dbbd1616efa2469e5b1990a61
2018-07-21 17:07:46 +00:00
Neels Hofmeyr 958f259f95 dissolve libbsc: move all to src/osmo-bsc, link .o files
Move all of libbsc/ into osmo-bsc/, and separate/move some implementations to
allow linking from utils/* and ipaccess/* without pulling in unccessary
dependencies.

Some utilities use gsm_network and gsm_bts structs, which already include data
structures for fairly advanced uses. Move initialization that only osmo-bsc
needs into new bsc_network_init() and bsc_bts_alloc_register() functions, so
that the leaner tools can use the old gsm_* versions without the need to link
everything (e.g. handover and lchan alloc code).

In some instances, there need to be stubs if to cut off linking "just before
the RSL level" and prevent dependencies from creeping in.
- abis_rsl_rcvmsg(): the only program currently interpreting RSL messages is
  osmo-bsc, the utils are merely concerned with OML, if at all.
- paging_flush_bts(): ip.access nanobts models call this when the RSL link is
  dropped. Only osmo-bsc actually needs to do anything there.
- on_gsm_ts_init(): the mechanism to trigger timeslot initialization is related
  to OML, while this action to take on init would pull in RSL dependencies.
utils/ and ipaccess/ each have a stubs.c file to implement these stubs. Tests
implement stubs inline where required.

From src/utils/, src/ipaccess/ and tests/*/, link in .o files from osmo-bsc/.
In order for this to work, the osmo-bsc subdir must be built before the other
source trees. (An alternative would be to include the .c files as sources, but
that would re-compile them in every source tree. Not a large burden really, but
unless linking .o files gives problems, let's have the quicker build.)

Minor obvious cleanups creep in with this patch, I will not bother to name them
individually now unless code review asks me to.

Rationale:

1) libbsc has been separate to use it for osmo-nitb and osmo-bsc in the old
openbsc.git. This is no longer required, and spreading over libbsc and osmo-bsc
is distracting.

2) Recently, ridiculous linking requirements have made adding new functions
cumbersome, because libbsc has started depending on osmo-bsc/*.c
implementations: on gscon FSM and bssap functions. For example, neither
bs11_config nor ipaccess-config nor bts_test need handover_cfg or BSSMAP
message composition. It makes no sense to link the entire osmo-bsc to it, nor
do we want to keep adding stubs to each linking realm.

Change-Id: I36a586726f5818121abe54d25654819fc451d3bf
2018-06-07 19:09:06 +02:00