... and warn if the size is not what we expect.
This is required to work with sysmobts-v2 firmware >= v2.1, as the
SuperFemto_Prim_t is now larger than the GsmL1_Prim_t.
SI5/SI6 and other messages on SACCH need the C/R and the EA bit set in
the LAPDm header. Most devices accept a broken header, but especially
the Wavecom Q2686 responds with tons of RR STATUS messages if there is
any invalid bit.
This allows us to do RF measurements (EDGE EVM and the like) even
without having any PCU/RLC/MAC code as of now.
To use it, configure PDCH type timeslots (e.g. TS 7) in the BSC and then
use "trx 0 7 activate 0" to manually activate the PDTCH lchan on top
of that timeslot. The BTS will now happily transmit EDGE/8PSK data.
The ciphering parameters in L1 are persistent accross MPH
deactivate/activate, so we need to make sure to always initialize them
cleanly at RSL CHAN ACT time. This has the added benefit that we can
also activate channels that have encryption enabled from the very
beginning (required for encrypted handover).
where previously we would only see
<0006> oml.c:931 (bts=0,trx=0,ts=1,ss=0) MPH-DEACTIVATE.req (FACCH/F)
we now get
<0006> oml.c:931 (bts=0,trx=0,ts=1,ss=0) MPH-DEACTIVATE.req (FACCH/F RxUL)
to notice it is modifying the receive path in the uplink direction.
Send the RSL ACT ACK/NACK after the Layer1 firmware has acked the
activation/deactivation. In case the channel can not be activated
we will send a NACK. In case the channel can not be deactivated we
will send an ACK and the next time the channel is activated we will
send a NACK. The release ack will be sent once the TxDownlink of the
TCH/SDCCH is closed.
Change the rsl_tx_chan_nack method to create a new msgb to be used
by the hardware layer, change the return value to ask the caller to
delete the msgb.
Use the deact_sach (renamed to deact_sacch in master) to remember if the
SACCH has been disabled. This should fix the case of lchan errors due releasing
the lchan twice.
Do not msgb_free the msg as it will be re-used inside the nack
method and return 1 so the caller does not free the msgb. This
ownership model needs some consideration but the usage of ref
counts will not yield good results.
If the deactivation is failing the channel needs to be moved into
and error state, if the deactivation completed the channel needs to
be set to the none state and set the state to release reqeust on
the deactivation.
This will make app -V print the copyright information like the other
applications of our universe. An BTS integration that want to list
additionaly copyright holders needs to access the vty_app_info and create
a new copyright string.
We now check if the received message is an LAPDm I frame in order to
determine if we have received the first valid encrypted message on the
radio link. This relates to the fact that we often see 'old' UI frames
coming up from L1, even after it has confirmed decryption has been
enabled.
When the RR CIPH MODE CMD is transmitted to the MS, we need to tell the
L1 to enable decryption on RX. After the first received frame has been
decrypted successfully, we will enable encryption also on transmit.
This has been tested with A5/1 so far, but A5/2 and A5/3 should work
exactly identical.
In L1 RTP mode, the L1 already does all the bit-shifting and re-ordering
required for the RTP formats (which have different bit/nibble order than
the ETSI/3GPP encodings, for some odd reason).
We don't enable it by default yet, as only HR/FR/EFR work with it, but
AMR has some yet to be debugged problem.
Enabling USE_L1_RTP_MODE would save some CPU cycles on the ARM side.
The old firmware does not expose separate queues for PDCH and TCH. The change
appears to be too intrusive and I will try to find a more elegant solution.
The compiler can not know that the "int priv_nr" will hold the
enum values of the write queue, add a default branch and add a
warning and an assert there.
l1_transp_hw.c:108:1: warning: control reaches end of non-void function [-Wreturn-type]
Use 't' modifier for pointer diff in the printf statement.
oml.c: In function ‘oml_rx_set_bts_attr’:
oml.c:403:3: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 9 has type ‘int’ [-Wformat]
femtobts.c:249:2: warning: excess elements in array initializer [enabled by default]
femtobts.c:249:2: warning: (near initialization for ‘femtobts_clksrc_names’) [enabled by default]
If we don't do this on recent L1, the L1 will refuse the open after
re-starting osmo-bts.
There still is an issue in case osmo-bts crashes. We should have a
respawn loop that re-loads the DSP firmware before re-starting osmo-bts,
just to make sure...
The TODO item still applies to somehow limit the queue of incoming
messages and drop older ones first. A sane limit would be the number
of channels (+ or * 2).
rc might not be initialized when going through the default
statement but also hitting a break inside the switch case
statement for GsmL1_Sapi_Sacch.
l1_if.c:530:2: warning: Undefined or garbage value returned to caller
return rc;
We have to
* merge the new attributes with the exiting TS (not BTS) attributes
* in case of success, attach the new merged attributes to our state
* in case of success, free the old attributes
Thanks to Holger for pointing this out.
If someone wants to have paging for a wrong frame, gracefully return
and do not fill the output buffer. Because we are on the wrong frame
I think it is best to not fill the frame, this is why I did not add a
check to l1_if.c to generate an empty frame.
We have to either lapdm_exit() both DCCH and ACCH (not 2x ACCH) or
rather call lapdm_channel_exit() which does that for us.
Thanks to Holger Freyther for spotting this bug.
The first one just sets the val to 0xffff, the second converted
the value to integer twice.
sysmobts_vty.c: In function ‘cfg_trx_clkcal_def’:
sysmobts_vty.c:109:15: warning: unused variable ‘clkcal’ [-Wunused-variable]
sysmobts_vty.c: In function ‘cfg_trx_clkcal’:
sysmobts_vty.c:122:15: warning: unused variable ‘clkcal’ [-Wunused-variable]
We now have to explicitly indicate the tchPlType at channel activation
type, so L1 knows which channel decoder to use (FR, EFR, AMR, ...)
Also, we properly implement the initial codec mode selection as per TS
05.09
* parse AMR multirate config form 04.08 IE into easier format
* CMR, CMC and CMI on the L1 side are an _index_ into the current
mode array
* Fix conversion of AMR SID frames from RTP -> L1
We don't really know if the HR encoding is compatible with other
equipment, but it _should_ follow Chapter 5.2 of ETSI TS 101 318.
Please note that RFC5993 also specifies a way to encode GSM-HR into RTP,
we do not try to be compatible with that. The only difference seems to
be one additional TOC octet at the beginning of the payload field.
Using osmo-bts-sysmo and this code, it is now possible to do FR and AMR
based voice calls on TCH/F.
A lot of CPU is wasted in the conversion between the RTP formats and the
L1 specific formats for the codec frames. All data needs to be shifted
by four bits, and the order of bits needs to be reversed in every byte.
This only implements creating, binding, connecting and free'ing RTP
sockets, not yet anything regarding receiving or transmitting codec
frames on them.
You will need the rtp branch of libosmocore for libosmotrau
We didn't correctly format the RSLms message that went into LAPDm,
causing LAPDm to drop the message.
Also, disable the fake CIPH MODE COMPLETE generation hack for now
When seinding the fake CIPH MOD COMPL, we should wait a bit, as otherwise it
will reach the MSC _before_ we ever get the (still unencrypted) CLASSMARK
update from the MS.
This is not full encrpytion support, the bts-model part still
needs to detect the ENCR CMD when de-queueing from LAPDm and enable
the de-ciphering, detect the arrival of the first encrypted frame,
etc, enable en-ciphering, ...
when we activate the SCH in the DSP, we start a 5-second timer. If
we ever do not receive any MPH-TIME.ind primitives from L1 within
that time frame, we stop the process (and will be re-spawned)
The BTS IP address can now be specified by the L1FWD_BTS_HOST env
variable.
Option parsing would not have been that easy to integrate without
touching the main program...
The sequence is as follows:
0) start osmo-bts
1) start connection attempts to BTS
2) issue L1-RESET.req
3) receive L1-RESET.conf
4) issue RF-ACTIVATE.req
5) receive RF-ACTIVATE.conf
6) receive attributes for TRX
7) receive opstart for TRX
8) issue MPH-INIT.req
[...]
The important point here is: We don't want the BSC to set TRX attributes or do
TRX opstart before our RF related hardware is initialized.
In SDCCH4, we use lchan number 0...3 for the SDCCH/SACCH, and
we statically use lchan[4] as the dummy for activating the CCCH
L1 SAPIs.
In order to make combined and non-combined CCCH orthogonal, we simply
also use lchan[4] in that case. On a 'pure' CCCH, therefore lchan
0..3 are unused and 4 is the actual CCCH.
the RACH burst detection in the physical layer is appranetly providing many
false positives, and we need to raise the bar a bit in order to not allocate
channels in a useless way...
* gather measurements from each PH-DATA.ind
* check every TDMA frame about meas period expiration
* compute averages after period expired
* put MS DL MEAS REP into RSL MEAS RES messages, include UL meas
bugs:
* L3 INFO content seems to have some offset
* is_sub is not set anywhere
* measurement periods might have up/downlink offset
This code re-works osmo-bts to add support for the upcoming sysmocom BTS.
It also tries to add some level of abstraction between the generic
part of a BTS (A-bis, RSL, OML, data structures, paging scheduling,
BCCH/AGCH scheduling, etc.) and the actual hardware-specific bits.
The hardware-specific bits are currently only implemented for the sysmocom
femtobts, but should be (re-)added for osmocom-bb, as well as a virtual
BTS for simulation purpose later.
The sysmocom bts specific parts require hardware-specific header files
which are (at least currently) not publicly distributed.
Harald Welte
Holger Hans Peter Freyther