Commit Graph

33 Commits

Author SHA1 Message Date
Neels Hofmeyr 2de0c8b9bb comments: describe some lchan details
(requested by pespin)

Change-Id: I04ec4ce1fd2b7b110bb496186aae39ecfbbc3628
2018-12-21 03:01:01 +01:00
Neels Hofmeyr 0277ab2139 make sure early lchan act failure resets the lchan
Fix crash after AMR configuration fails.

The crash is due to an assertion that finds a non-NULL conn in the lchan, when
re-using an lchan that has failed in AMR configuration earlier on. That is
because the AMR config still happens in state UNUSED.

  DCHAN ERROR lchan(0-0-2-TCH_F_TCH_H_PDCH-0)[0x6120000066a0]{UNUSED}: (type=TCH_F) lchan allocation failed in state UNUSED: Can not generate multirate configuration IE
  ...
  DCHAN DEBUG lchan(0-0-2-TCH_F_TCH_H_PDCH-0)[0x6120000066a0]{UNUSED}: (type=TCH_F) After failure handling, already in state UNUSED
  ...
  ...
  DCHAN DEBUG lchan(0-0-2-TCH_F_TCH_H_PDCH-0)[0x6120000066a0]{UNUSED}: Received Event LCHAN_EV_ACTIVATE (lchan_fsm.c:324)
  Assert failed !lchan->conn ../../../../src/osmo-bsc/src/osmo-bsc/lchan_fsm.c:491

The FSM design idea is that when returning to the UNUSED state, all lchan state
is cleared. However, when calling lchan_activate(), a failure may happen still
in state UNUSED, so that we don't transition *back* to UNUSED properly.

So, first transition out of UNUSED before failures can happen. (Other ways to
solve this would be to invoke lchan clearing even if already in UNUSED, but
semantically, transitioning first makes more sense.)

Upon LCHAN_EV_ACTIVATE, just remember the lchan_activate_info and transition to
WAIT_TS_READY, so that on lchan_fail(), we can normally transition back to
UNUSED and clear the lchan.

Move the initial lchan activation code to lchan_fsm_wait_ts_ready_onenter().

Also, there is a bit of duplication of members of the lchan->activate (lchan
state) and the lchan_activate_info (passed to lchan_activate()) structs. The
fix for this also removes the dup:

Add struct lchan_activate_info as child struct at lchan->activate.info, drop
the other lchan->activate members that would dup .info.*. Move struct
lchan_activate_info declaration to gsm_data.h.

Apply the new '.info' member struct throughout the code.

Related: OS#3737
Change-Id: Ide665b10fa3f4583059c55346db8da833959e3cc
2018-12-21 02:56:24 +01:00
Neels Hofmeyr 64a3bbe093 debug log: log almost all stages of speech codec negotiation
Trying to understand the stages of speech codec limitations, I came up with
this logging. Keep it for future problem solving.

It looks like this:

  DCHAN DEBUG test_codec_pref: HR3 matches gsm0808_channel_type->perm_spch[3] (codec_pref.c:146)
  DCHAN DEBUG test_codec_pref: permitted speech = HR3 corresponds to speech codec type = HR3 (codec_pref.c:174)
  DCHAN DEBUG test_codec_pref: speech_codec_list[3] matches speech codec type HR3 (codec_pref.c:182)
  DCHAN DEBUG match_codec_pref: msc->audio_support[0] = HR3: matches channel type and speech codec list (codec_pref.c:329)
  DCHAN DEBUG match_codec_pref: perm_spch=HR3 corresponds to chan_mode=SPEECH_AMR (codec_pref.c:357)
  DCHAN DEBUG match_codec_pref: perm_spch=HR3 is AMR (codec_pref.c:363)
  DCHAN DEBUG gen_bss_supported_amr_s15_s0: HR: bts->mr_half.gsm48_ie[1] = 0x36 ==> amr_cfg_bts=0x0736 (codec_pref.c:267)
  DCHAN DEBUG match_codec_pref: sc_match=HR3 & amr_s15_s0_supported=0x0600 = 0x0600 (codec_pref.c:376)
  DCHAN DEBUG Found matching audio type: half rate SPEECH_AMR for channel_type = { ch_indctr=0x1, ch_rate_type=0xa, perm_spch=[ 21 11 01 25 05 ] }, s15_s0=0x0600 (osmo_bsc_bssap.c:737)
  DCHAN DEBUG perm_spch[0] = 0x21 = FR3 (osmo_bsc_bssap.c:742)
  DCHAN DEBUG perm_spch[1] = 0x11 = FR2 (osmo_bsc_bssap.c:742)
  DCHAN DEBUG perm_spch[2] = 0x01 = FR1 (osmo_bsc_bssap.c:742)
  DCHAN DEBUG perm_spch[3] = 0x25 = HR3 (osmo_bsc_bssap.c:742)
  DCHAN DEBUG perm_spch[4] = 0x05 = HR1 (osmo_bsc_bssap.c:742)
  ...
  DCHAN DEBUG lchan(0-0-2-TCH_F_TCH_H_PDCH-0)[0x612000006520]{WAIT_TS_READY}: (type=TCH_H) AMR rate configurations: MSC=0x8 & BTS=0xa = 0x8 (lchan_fsm.c:455)

Change-Id: Ida4e7e0cf27e8c6e502061a5c41e8b51f533d3dd
2018-12-21 02:05:08 +01:00
Neels Hofmeyr aecee598a1 err log: suggest ways to resolve AMR modes mismatch
Speech modes are limited by so many things that it can be hard to realize a
simple mismatch in the osmo-bsc.cfg between 'msc' allowed AMR rates and the
rates allowed in the per-bts 'amr tch-x modes'. Explicitly hint at that.

It looks like this:

  DCHAN ERROR lchan(0-0-2-TCH_F_TCH_H_PDCH-0)[0x612000006520]{WAIT_TS_READY}: (type=TCH_H) Intersection of AMR rate configurations is empty: osmo-bsc.cfg=0x08 & requested-codec-list=0x02. In the config: make sure that the 'msc'/'amr-config' allows AMR rates that are also allowed in 'network'/'bts N'/'amr tch-h modes ...' (lchan_fsm.c:449)

Change-Id: Idaf212ca5ec6d0d77f2421860a040bf4524b25a6
2018-12-21 02:05:08 +01:00
Pau Espin 4af2d18814 bsc: lchan_fsm: Fix invalid duplicated transition
When we enter WAIT_RLL_RTP_RELEASED
(lchan_fsm_wait_rll_rtp_released_onenter), we call lchan_do_release()
which in turn dispatches LCHAN_RTP_EV_RELEASE to lchan_rtp_fsm.c, which
will dispatch back an LCHAN_EV_RTP_RELEASED event, which will be handled
by lchan_fsm_wait_rll_rtp_released(), which will change state to
WAIT_BEFORE_RF_RELEASE. When going back the stack (return), we are still
in lchan_fsm_wait_rll_rtp_released_onenter() which again triggers a
change state to WAIT_BEFORE_RF_RELEASE because it checks same conditions
than first one.

20181128203727051 DCHAN osmo-bsc/lchan_fsm.c:1388 lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0]{ESTABLISHED}: lchan detaches from conn SUBSCR_CONN(conn3)[0x612000002da0]
20181128203727051 DMSC osmo-bsc/lchan_fsm.c:1391 SUBSCR_CONN(conn3)[0x612000002da0]{CLEARING}: lchan lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0] detaches from conn
20181128203727051 DCHAN osmo-bsc/lchan_fsm.c:1359 lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0]{ESTABLISHED}: state_chg to WAIT_RLL_RTP_RELEASED
20181128203727052 DCHAN osmo-bsc/lchan_fsm.c:959 lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0]{WAIT_RLL_RTP_RELEASED}: (type=TCH_F) SAPI[0] = 1
20181128203727052 DRR osmo-bsc/gsm_04_08_rr.c:254 Sending Channel Release: Chan: Number: 0 Type: 2
20181128203727052 DCHAN osmo-bsc/lchan_fsm.c:945 lchan_rtp(0-0-6-TCH_F_PDCH-0)[0x6120000027a0]{ESTABLISHED}: Received Event LCHAN_RTP_EV_RELEASE
20181128203727052 DCHAN osmo-bsc/lchan_rtp_fsm.c:572 lchan_rtp(0-0-6-TCH_F_PDCH-0)[0x6120000027a0]{ESTABLISHED}: Terminating (cause = OSMO_FSM_TERM_REGULAR)
20181128203727052 DCHAN osmo-bsc/lchan_rtp_fsm.c:572 lchan_rtp(0-0-6-TCH_F_PDCH-0)[0x6120000027a0]{ESTABLISHED}: Removing from parent lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0]
20181128203727052 DCHAN osmo-bsc/lchan_rtp_fsm.c:572 lchan_rtp(0-0-6-TCH_F_PDCH-0)[0x6120000027a0]{ESTABLISHED}: Freeing instance
20181128203727052 DCHAN fsm.c:381 lchan_rtp(0-0-6-TCH_F_PDCH-0)[0x6120000027a0]{ESTABLISHED}: Deallocated
20181128203727052 DCHAN osmo-bsc/lchan_rtp_fsm.c:572 lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0]{WAIT_RLL_RTP_RELEASED}: Received Event LCHAN_EV_RTP_RELEASED
20181128203727052 DCHAN osmo-bsc/lchan_fsm.c:856 lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0]{WAIT_RLL_RTP_RELEASED}: (type=TCH_F) Still active SAPIs: 0
20181128203727052 DCHAN osmo-bsc/lchan_fsm.c:1011 lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0]{WAIT_RLL_RTP_RELEASED}: state_chg to WAIT_BEFORE_RF_RELEASE
20181128203727052 DRSL osmo-bsc/abis_rsl.c:633 (bts=0,trx=0,ts=6,ss=0) DEACTivate SACCH CMD
20181128203727052 DCHAN osmo-bsc/lchan_fsm.c:986 lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0]{WAIT_BEFORE_RF_RELEASE}: transition to state WAIT_BEFORE_RF_RELEASE not permitted!

Change-Id: I5d95bbd8244cc8e9c1cfb6fe0f76148332386a3d
2018-12-05 16:06:47 +00:00
Pau Espin 35b979cc0c bsc: lchan_fsm: Add missing transition WAIT_TS_READY->WAIT_RLL_RTP_RELEASED
20181128193707326 DCHAN osmo-bsc/lchan_rtp_fsm.c:193 lchan_rtp(0-0-6-TCH_F_PDCH-0)[0x612000002320]{WAIT_MGW_ENDPOINT_AVAILABLE}: Freeing instance
20181128193707327 DCHAN fsm.c:381 lchan_rtp(0-0-6-TCH_F_PDCH-0)[0x612000002320]{WAIT_MGW_ENDPOINT_AVAILABLE}: Deallocated
20181128193707327 DCHAN osmo-bsc/lchan_rtp_fsm.c:193 lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0]{WAIT_TS_READY}: Received Event LCHAN_EV_RTP_RELEASED
20181128193707330 DCHAN osmo-bsc/lchan_fsm.c:1347 lchan(0-0-6-TCH_F_PDCH-0)[0x6120000039a0]{WAIT_TS_READY}: transition to state WAIT_RLL_RTP_RELEASED not permitted!

Change-Id: I43aab5ed8ac369869b191b3b7c938ce4985ab849
2018-12-05 16:06:47 +00:00
Neels Hofmeyr 24482ad4e2 follow-up: logging tweak for Immediate Assignment
follow-up to I9ad094d272254d7aee9b0a676201d4ed8cd727ca because it was merged
before fixeria's code review could be incorporated.

Change-Id: I474cf1a58d1f00ec5b0ae52bd095a60aad763975
2018-11-30 19:33:27 +01:00
Neels Hofmeyr 369fba25de send Immediate Assignment Reject only before Immediate Assignment
Set flag lchan->activate.immediate_assignment_sent to true when sending, and
omit a reject after that.

lchan->activate gets completely zeroed in lchan_reset(), which sets that flag
back to false whenever an lchan becomes inactive.

Related: OS#3709
Change-Id: I9ad094d272254d7aee9b0a676201d4ed8cd727ca
2018-11-27 01:35:15 +01:00
Neels Hofmeyr ad2c15da14 lchan: set cause for 4 instances of release_in_error = true
Make sure some RSL cause is set.

Change-Id: I372ade9fc58919fbf858ce14caab8a0a22dbb083
2018-11-14 17:33:00 +01:00
Neels Hofmeyr eee24eb964 cosmetic: lchan: introduce sub-struct lchan->release.*
Put all lchan release related flags and settings in a sub-struct named
'release' to better indicate what those fields are for. There is no functional
change.

Change-Id: Icfddc6010e5d7c309f1a7ed3526b5b635ffeaf11
2018-11-14 17:33:00 +01:00
Neels Hofmeyr 5b1a7d1e9b lchan release: always Deact SACCH
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
2018-11-14 16:16:30 +00:00
Neels Hofmeyr d30922f7a3 lchan: release in error: fix missing messages / events
In the case where there is a release in error and we skip immediately to the RF
Release state, send all of Deact SACCH, RR Release messages and also signal the
lchan_rtp_fsm as appropriate.

Move that code to static lchan_do_release() and call from both
lchan_fsm_wait_rll_rtp_released_onenter() in the normal case, as well as
lchan_release() when skipping that.

When releasing in error, but we're already in LCHAN_ST_WAIT_RLL_RTP_RELEASED,
those messages have already been sent and we can skip them.

Change-Id: I648a9826ce56b611359f81462ca03e4ab4c736aa
2018-11-14 16:16:30 +00:00
Neels Hofmeyr 478e991a78 fix: send RR Release (e.g. after BSSMAP Clear Cmd)
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
2018-11-14 16:16:30 +00:00
Neels Hofmeyr 946d1fb5c7 dbug log: verbosely detach conn<->lchan
When reading the log of OS#3686, I wished for explicit logging of when exactly
an lchan disassociates from a conn. Here is the debug logging I would have
liked to see.

I'm not sure whether we really need to merge this patch...

Change-Id: I97558b899e7f2578ba98287e7352dc072d02ce44
2018-11-09 23:54:59 +01:00
Neels Hofmeyr 64b092e855 lchan: rf release: make sure conn is NULL
lchan_fsm_wait_rf_release_ack_onenter() calls gscon_forget_lchan(). At the
point where the conn has no lchan, the lchan must not have a conn. Make sure
that conn is NULL after gscon_forget_lchan().

I hope this fixes OS#3686, it is the only situation I could find where the
disassociation is potentially one-sided.

I get the feeling that this should be hardcoded in gscon_forget_lchan(), but I
dimly remember other situations that are less trivial, where it doesn't
necessarily make sense to forget reciprocically. So only fixing this one now.

Related: OS#3686
Change-Id: If0c6e495e419b9dbb44443c3fc3f54dd4b714aa5
2018-11-09 23:54:59 +01:00
Neels Hofmeyr fc9449c688 lchan_fsm_cleanup: drop redundant 'forget_lchan' call
Right below this call, we invoke lchan_reset(), and the first thing it does is
gscon_forget_lchan(). Drop this redundant invocation.

Change-Id: I503efceb6d34c8df0cdfef3dfc83fa1e61271c47
2018-11-09 23:54:59 +01:00
Philipp Maier 9108d47f4a lchan_fsm: generate proper multirate configuration IE on RSL
During the generation of the multirate configuration IE in the channel
activation message that is sent over RSL, all AMR rates except the
highest one are trimmed. This was to ensure that the multirate
configuration IE only contains one codec rate per active set. Lets fix
that and generate a proper IE with threshold and hysteresis values.

- extend lchan_mr_config so that it can generate a full multirate
  configuration IE

Change-Id: I7f9f8e8d9e2724cbe3ce2f3599bc0e5185fd8453
Related: OS#3529
2018-10-24 09:22:41 +02:00
Neels Hofmeyr 6fe125294b lchan_fsm: notify conn of released lchan upon RF Release
Related: osmo-ttcn3-hacks If772dbbc5f9790d3f911465e1303dd0a99811154
Change-Id: I7621616c24588c2db15ad1ae7ca68cfa0fb76f66
2018-10-12 12:42:26 +02:00
Neels Hofmeyr 0d91fb5ed1 lchan_fsm: fix failure handling: notify conn when released
Usually, conn->lchan is set to NULL before/upon releasing it. However, if the
lchan is still associated with a conn upon/after release, make sure the conn
realizes it has no lchan and sends a BSSMAP Clear Request to the MSC.

lchan_reset() is the last step before an lchan is fully unused. In there, make
sure to notify any conn that might still be associated, with
gscon_forget_lchan().

lchan_cleanup() does the same, but in fact this is only called when an lchan is
*deallocated*, but instead it usually merely goes to the UNUSED state.

It may make sense to call gscon_forget_lchan() sooner, e.g. when entering a
releasing state. This here nevertheless is a final safeguard.

Related: osmo-ttcn3-hacks If772dbbc5f9790d3f911465e1303dd0a99811154
Change-Id: I88337a18246c44ba48da64bb611a3cbb647a750e
2018-10-12 06:21:35 +00:00
Philipp Maier c9a4f697d3 codec_pref: handle S0-S15 in ASSIGNMENT REQUEST
Opposed to all other codecs that are common in GSM, AMR requires a codec
configuration that is expressed by a bitmask (S0 to S15) in the speech
codec list in the ASSIGNMENT REQUEST. Also the BSC acknowledges those
configuration in the ASSIGNMENT COMPLETE message.

At the moment osmo-bsc ignores all incoming configuration bits. The bits
in the ASSIGNMENT COMPLETE speech codec (choosen) field are hardcoded.

- Store the configuration bits while parsing the ASSIGNMENT COMPLETE
- Create an intersection with the configuration that is actually
  supported by the BSS
- Return the resulting (chosen) configuration bits with the assignment
  complete message.
- Use the (highest of the) agreed codec rates in RSL channel activation.

Change-Id: I2d8ded51b3eb4c003fe2da6f2d6f48d001b73737
Related: OS#3529
2018-10-05 07:58:22 +00:00
Neels Hofmeyr 526b4a5f35 ts,lchan_fsm: do not attempt to allocate CBCH subslots
In case a given channel combination contains a CBCH, it replaces sub-slot 2
with a CBCH, i.e. we must not attempt to allocate the same for SDCCH.

On timeslot initialization, immediately place such an lchan FSM into new state
LCHAN_ST_CBCH, so that it never appears unused and never is picked during
lchan_select(). Also set lchan->type = GSM_LCHAN_CBCH.

Verified by configuring CBCH timeslots and watching 'show lchan summary'.

Immediately after RSL and OML are up, these pchan types show lchan 2 in state
CBCH:

  BTS 0, TRX 0, Timeslot 0 CCCH+SDCCH4+CBCH, Lchan 2, Type CBCH, State CBCH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm
  BTS 0, TRX 0, Timeslot 1 SDCCH8+CBCH, Lchan 2, Type CBCH, State CBCH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm

With a 'phys_chan_config ccch+sdcch4+cbch' and three phones simultaneously
requesting USSD, I see:

  BTS 0, TRX 0, Timeslot 0 CCCH+SDCCH4+CBCH, Lchan 0, Type SDCCH, State ESTABLISHED - L1 MS Power: 14 dBm RXL-FULL-dl:  -53 dBm RXL-FULL-ul:  -47 dBm
  BTS 0, TRX 0, Timeslot 0 CCCH+SDCCH4+CBCH, Lchan 1, Type SDCCH, State ESTABLISHED - L1 MS Power: 30 dBm RXL-FULL-dl:  -47 dBm RXL-FULL-ul:  -47 dBm
  BTS 0, TRX 0, Timeslot 0 CCCH+SDCCH4+CBCH, Lchan 2, Type CBCH, State CBCH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm
  BTS 0, TRX 0, Timeslot 0 CCCH+SDCCH4+CBCH, Lchan 3, Type SDCCH, State ESTABLISHED - L1 MS Power: 16 dBm RXL-FULL-dl:  -47 dBm RXL-FULL-ul:  -47 dBm

With 'phys_chan_config SDCCH8+CBCH' and three phones simultaneously attaching,
I see:

  BTS 0, TRX 0, Timeslot 1 SDCCH8+CBCH, Lchan 0, Type SDCCH, State WAIT_RLL_RTP_ESTABLISH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm
  BTS 0, TRX 0, Timeslot 1 SDCCH8+CBCH, Lchan 1, Type SDCCH, State WAIT_RLL_RTP_ESTABLISH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm
  BTS 0, TRX 0, Timeslot 1 SDCCH8+CBCH, Lchan 2, Type CBCH, State CBCH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm
  BTS 0, TRX 0, Timeslot 1 SDCCH8+CBCH, Lchan 3, Type SDCCH, State WAIT_RLL_RTP_ESTABLISH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm

i.e. in all cases the CBCH lchan remains occupied and is not allocated as
SDCCH.

Detaching and re-attaching the BTS reliably brings back the CBCH state. Also
verified that changing the osmo-bsc config from telnet vty and dropping oml
followed by the BTS re-attaching brings back the CBCH state.

Change-Id: I2bafc5f696e818e38f8907ad0c8f38494df0623d
2018-09-11 02:08:41 +02:00
Neels Hofmeyr 021971781d lchan_fsm: allow late RTP release events without erroring
Change-Id: Ia463f97402b957bd13a95d18d291d1c1f006f089
2018-09-10 00:51:35 +00:00
Neels Hofmeyr dd6849da18 lchan: pick proper power and ta values
When activating an lchan, the power levels should be maximum and TA zero. Only
if a new lchan is assigned within the same cell does it make sense to take over
the previous power and TA levels.

In LCHAN_EV_ACTIVATE:

- Separate the code that copies previous encryption data. This should happen
  regardless of whether we're staying in the same cell or not.

- For the power,TA levels, take over an old lchan's values only when it is
  assigning a new lchan in the same cell.

Change-Id: I360b003398487fa6f934296ff03643c33ec61a35
2018-08-29 14:14:32 +02:00
Neels Hofmeyr f213fcbd43 cosmetic: lchan activ: drop todo comments
Drop the todo comments about "for_conn->encr". I have intended that as an idea
to store encryption info in the conn instead of the lchan, which might make
sense, but there's no use in these comments.

Change-Id: I47e90062c784dd7919fff3115e2bee3314b30cd5
2018-08-29 14:13:44 +02:00
Neels Hofmeyr 8d4faf10cd cosmetic: lchan activ: no need to clear mr again
In lchan state UNUSED, on activating an lchan, we zero out the lchan->mr_ms_lv
and mr_bts_lv. However, in UNUSED's onenter function, we already called
lchan_reset(), clearing out the lchan completely.

Drop two lines of unnecessary code.

Change-Id: I8b38f222f1c8c822e8e5e776850dbc60e30e8b8d
2018-08-29 13:58:42 +02:00
Neels Hofmeyr 193c1e3ab0 lchan_fsm: safer 'concluded' flag
The flag lchan->activate.concluded prevents entering the
lchan_on_fully_established()/lchan_on_activation_failure() more than once. So
far it was checked by callers, instead place in the functions themselves.

There is a potential functional change here, since during lchan_fail(), the
concluded flag was set only after entering lchan_on_activation_failure(). Now
it is already set at the start and prevents multiple re-entry beyond doubt.

This patch is not a result of an actual observed faulty behavior, just from
reading the code and seeing the slight loophole.

Change-Id: I0c906438b05442d66255203eb816453b7193a6d8
2018-08-29 02:02:10 +02:00
Neels Hofmeyr e23e1aeec2 cosmetic: lchan_fsm failure: log about state transitions
Early on during failure, log which state transition is intended after failure
handling.

If such state is already reached after failure handling, do not log "state
transition not permitted", but rather skip the state change and log "Already in
state X".

Change-Id: I81f53b38637823e62860cb773b7573bb5c21fdb0
2018-08-29 02:02:10 +02:00
Neels Hofmeyr 3ea8baeab0 lchan_fsm: lchan_fail_to(): store target state early
lchan_fail_to() is a macro to preserve useful source file:line information in
logging. But a side effect is that its target state argument might evaluate
differently at the end of the macro, if, say, the fi->state has changed.

I hit such an instance on timeout of WAIT_RLL_RTP_ESTABLISH:
lchan_fsm_timer_cb() calls macro lchan_fail(), which calls
lchan_fail_to(lchan_fsm_on_error[fi->state]). Unlike for normal function
invocation, this argument changes as fi->state changes. Since releasing the
lchan_rtp_fsm already transitions the lchan fi into WAIT_RF_RELEASE_ACK, the
final state change of lchan_fail_to() suddenly evaluates to the broken state
instead of the intended WAIT_RF_RELEASE_ACK.

Early in lchan_fail_to(), store the argument's value as of macro invocation.

Change-Id: Id9bf4580a112ee5629f553a8bcb6b5b03b1c5f53
2018-08-29 02:02:10 +02:00
Neels Hofmeyr 3c5612f82b create separate logging categories for lchan,ts,as FSMs
Change-Id: Ie889b8860a4a63c7c22ef65025f690d64cd7330c
2018-07-28 12:18:23 +02:00
Neels Hofmeyr d5df9a1d0d lchan_fsm: add in_release_handler flag
If a release event is being handled, ignore other ricocheting release events
until that release handling has concluded.

For example, if an lchan is regularly released, it signals the lchan RTP FSM to
release, which then calls back to say "RTP is released" on termination -- this
should not trigger other state changes than the initial release intends.

Change-Id: Iec41e006b6ab9d0f618d36925341f9536353e5d8
2018-07-28 12:18:23 +02:00
Neels Hofmeyr ac85b34476 lchan_fsm: split off lchan_rtp_fsm, establish RTP a bit earlier
Change-Id: Id7a4407d9b63be05ce63f5f2768b7d7e3d5c86fb
2018-07-28 12:18:23 +02:00
Neels Hofmeyr 73ecfbb822 cosmetic: FSMs: allow ignorable events
In various FSMs, some events may appear later or earlier without need of
action. Do not indicate these as 'ERROR' (event not permitted), but allow and
ignore them.

Debug-log about some of those.

From the old code, we've taken over the habit to change into
WAIT_BEFORE_RF_RELEASE even before SAPI[0] is released. Hence we may still
receive a SAPI[0] REL_IND in WAIT_BEFORE_RF_RELEASE. Don't show this as error
message, just silently accept it.

Change-Id: Ie320c7c6a1436184aaf2ec5a1843e04f4b3414ab
2018-07-28 12:18:23 +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