This is implemented by not freeing the subscriber when the
reference count becomes smaller than zero. We hope that this
will save many database accesses during the congres.
Instead of sending many messages we will queue the OML
messages and wait for the ACK/NACK before sending the
next message from the queue. We tag the msgb to remember
if we need to wait for an ack or not.
We keep the order of all messages, on ACKs and similiar
occassions we will drown the queue until we reach a message
that needs to be acked and then wait for that ack again.
Possible breakage can appear when we send an OML (e.g.
BS11 specific message) msg which does not need to be acked
through the abis_nm_sendmsg call. The fix will be to use
the _direct version of this method.
Re-Enable as it might have fixed something... who knows.
Conflicts:
openbsc/include/openbsc/abis_nm.h
openbsc/include/openbsc/gsm_data.h
openbsc/src/abis_nm.c
openbsc/src/gsm_data.c
The default values are those where the parameters are encoded
as '0' and they're not output in the config file if that case
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
In case of a inflexible network it is better to hardcode
the rtp payload to a given type. E.g. when using AMR5.9 on
a TCH/F and TCH/H having the same payload is helpful. For
now this will be only used by the osmo-bsc.
Only page if we have a load that is acceptable for paging. This
option is off by default, and can be enabled per bts. The idea
is that when we have no resources right now we will not page as
it will only create more RACHs and increase the load.
By default we are keeping the old behavior to always page and
only by changing a setting one is using the new behavior.
It might be that we run down to zero available slots but the BTS
might not send us a load indication. This can happen if we think
we send paging requests and the BTS disagrees and considers them
as errors and does not count the paging message.
When we drop to zero we will start a credit timer to give us extra
credit after six seconds, if we get a CCCH load indication before
we will stop the timer.
It is possible that the MSC is not sending the channel type it
needs for the operations it wants to do. Add a configuration option
to assign a TCH in case of paging any requests. It can be a good
idea to leave SDCCHs free for location updating requests and use
the TCH for SMS-MT and CC-MT.
Store the mapping from request to channel type in the GSM Network
struct as there is some policy involved with handling the request.
E.g. in a half rate network we don't want emergy calls to be getting
a TCH/F, or we want to have a different policy for early/late assignment
of phone calls. Update the table when creating the network and when
the neci is changed.
Allow the MS to use uplink discontinous transmission by
setting the right bit in the SystemInformation and set
DTXd/DTXu on the RSL channel commands.
This is configurable via dtx-used (0|1) on the network
level and still considered as experimental.
Currently every SAPI release indication will trigger the channel. It
was possible that we had SAPI=3 and SAPI=0 allocated and we tried to
release the channel by sending a RF Channel Release, the BTS answered
with a RF Channel Release ACK but also sent the SAPI Release Indication
which triggered a channel release here. So it was possible that we
would have released a newly allocated channel because of the SAPI
release of the old connection.
This code now works by releasing all SAPIs from highest to lowest,
then sending a SACH Deactivate and finally releasing the channel. This
approach is in use on the on-waves/bsc-master.
Also, we now re-start the network listen test after it has finished,
so if you run a test from ipaccess-find, the test will get re-started
and re-started all the time.
* We should create the transaction for SMS, CC on the CM Service Request
but for now we will use a band aid and create a dummy operarion to wait
five seconds for the transaction to be opened.
The transaction should not know on which lchan we are operating
as this can change due handover. Add untested code to share the
subscriber connection of the new and old lchan and move the pointer
in case of success/failure. Also on a clear command we will free
any resources allocated...
This code is not tested and needs to be debugged, but it should
have the right structure. I am going to fix a potential memleak
in the next commit.
A channel will be released in case of
* Errors via the clear_request callback...
* no more transactions and operations are going on.
This means that if we do something without a transaction
the channel might be closed down right away. The bug fix
will be to create a transaction/operation.
This is a big change to the way we use the subscriber
connection. From now on it is is dynamically allocated
and we will slowly move from a 1:1 lchan to conn to
having more than one lchan per connection.
This is the first commit, the subscr_con* methods will
move to gsm_data once the use_count is removed from the
connection, the freeing of the connection will also change.
The Channel Activate might be sent to a different TRX than the
Immediate Assignment. So we need to make sure that the channel
is activated before we send the immediate assignment for the RACH.
Another reason for that is according to GSM 08.58 we should take
the frame number from the activate and use it for the starting
time inside the immediate assignment message. We obviously do not
do this yet.
The code assumes that the BTS will either respond with a CHAN ACK
or a CHAN NACK if not the lchan will remain in the request state.
Also, make sure the bit ordering in the pre-computed MA is correct,
as well as the cell channel description of the target cell being
present in the HO CMD.
We now compute the Cell Channel Description for SI 1 by bit-wise
OR of the ARFCN bitmask of each timeslot on all the TRX of the BTS.
Also, support generating a GSM 04.08 Channel Description IE for
the hopping case (with HSN/MAIO instead of ARFCN).
What's still missing now: Sending the 04.08 Mobile Allocation IE
Allow to set the TOS field via the VTY interface. The
SO_PRIORITY was not used as it has no effect on the
packets being sent (in contrast to the documentation).
When submitting a DTAP message, the BSC API will attempt to
establish the RLL layer and then send the message or send an
SAPI n REJECT. This will be used by the SMS code.
This will take care of the auth/check/enable cipher sequence
and call a callback function when done.
Currently the negotiated Kc is saved but not re-used, so
there is an authentication each time ...
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
When we issue a RF Channel Release in case of a failure we receive
RLL release indications after the channel was tearn down and we
issue another RF Channel Release as a result. The channel allocator
might have already allocated this channel and we release the channel
again with another MS on it.
Make rsl_rf_chan_release take an error argument and make it set
a new state in case of an error and change the RF Channel Release
ack to not set the state back to none in case of an error but wait
for a timeout that is a bit higher than T3111.
I tested this with removing the battery during a phonecall and
waiting for the channel failure. With this test we only send the
release once.
BSSGP stores a pointer to the Cell Identifier IE in msgb->cb, which
is later used by the GMM layer to identify the cell that has sent a
given message.
This now also means that the gsm_04_08_gprs.c code is free of any
legacy references to msg->trx or struct gsm_bts.
We now expect the highest level (actual SGSN GMM code) to know
all identifiers for every element in the protocol stack, i.e.
TLLI, SAPI, BVCI and NSEI. The layer-inetrnal state is looked
up based on those identifiers.
The reason for this is to ensure only the highest level state
needs to be persistent, while everything else can be regenerated
dynamically (e.g. in a SGSN restart)
In the old code
l3h = BSSGP, l4h = LLC, cb[gmmh] = 04.08
Now, this has been changed to
cb[bssgph] = BSSGP, cb[llch] = LLC, l3h = 04.08
This way, GSM general 04.08 and GPRS 04.08 code can expect a
GSM 04.08 header at msgb->l3h
According to TS 08.16, the BSSGP layer needs to specify NSEI and BVCI when
executing the NS UNITDATA REQUEST primitive of the underlying NS layer.
Rather than passing around a pointer to the 'struct gprs_nsvc', we now
have NSEI and BVCI as members of 'struct obsc_msgb_cb' and set them
when BSSGP hands a message down to NS.
NS then does a lookup of the 'gprs_nsvc' based on the NSEI parameter.
The explicit 'tlli, gmmh' members of struct msgb are gone from
current libosmocore and have been replaced by the more generic
'control buffer' mechanism.
Be able to tune the RACH settings of the BTS via the vty interface,
by default they are initialized to -1 which means we will use the
content of the static array (BTS default) and can be changed via
the VTY interface. I have verified the setting on the nanoBTS with
wireshark and I have tested writing the config file.
For GSM V1 FR, the payload type is fixed to 3 in the RFC.
But for the other codecs, the payload type is dynamically assigned
between 96 and 127. Here, we use a static mapping internal to OpenBSC.
This patch is needed to make a rather old 139 unit (with sw version
120a002_v149b42d0) work with something else than FR codec. I also tested
this patch on a newer 139 (with sw version 120a352_v267b22d0) to make
sure it didn't add a regression. More testing with newer EDGE units
should be done by whoever has some of theses.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
The current code was overly complex. It tried to iterate over
the list in a round robin and we had to keep track of the last
element, see if we remove that one, check if the list becomes
empty... This can all replaced by treating the double linked
list as a queue. We take the item at the front, do something
on it and then and then put it back to the list at the end.
This new gprs-conf branch is intended to contain everything needed
to configure GPRS in the nanoBTS, but without implementing the SGSN/GGSN
functionality.
The SGSN/GGSN development will happen in a branch based on this branch
called "gprs-sgsn"
This library is intended to collect all generic/common funcitionality
of all Osmocom.org projects, including OpenBSC but also OsmocomBB
The library currently includes the following modules:
bitvec, comp128, gsm_utils, msgb, select, signal, statistics, talloc, timer,
tlv_parse, linuxlist
msgb allocation error debugging had to be temporarily disabled as it depends on
'debug.c' functionality which at the moment remains in OpenBSC
Some NM attributes are defined differently depending on
the BTS type. Having one big nm_att_tlvdef[] table for
all BTS types is no longer sufficient. This patch
* introduces 'struct gsm_bts_model' to describe a BTS model
* adds definitions of gsm_bts_model for BS-11 and nanoBTS
* changes the abis_nm_tlv_parse() function: include a bts pointer
Theses will be useful to know if we can reuse the tuples or if
we should renew. The 'issued' is currently purely informative.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
* On start the vty code will call the abis_nm method and this
will set the administrative state to unlock/lock
* During startup the BTS will report its state as well and would
possible overwrite the set administrative. We are only going
to update the administrative if it was 0 before. This appears
to work on all of my tests. In case this will not be the case
for others we will have to split the administrative into two
sets one for the BTS and one for the BSC.
In many cases we actually want a name / unique ID for the lchan,
not just for the on-air timeslot... especially in SDCCH/8 case,
where 8 SDCCHs share one timeslot...
When we allocate a channel, we send the RSL CHAN ACT REQ and wait until we get
a CHAN ACT ACK. Only the ACK will change the state, so there is a race where
we allocate that same channel to a different channel request before we get
the ACT ACK.
Introducing a new ACT_REQ state resolves this issue.
This has the advantage that counters can be added all over the code
very easily, while having only one routine that stores all of the
current counter values to the database. The counters are synced
every 60 seconds, providing relatively fine grained statistics
about the network usage as time passes by.
This implements the handover algorithm (and associated parameters)
as described in Chapter 8 of the book "Performance Enhancements in
a Frequency |Hopping GSM Network" by Thomas Toftegard Nielsen and Jeroen
Wigard.
The parameters such as averaging windows are configured in struct
gsm_network. We keep some state to trakc up to 10 neighbors as
they are being reported from the MS.
This has so far only been tested in a network with two BTS that
have each other as neighbor. Networks with morge neighbors might
encounter bugs.
This allows us to block packets that we have received after the channel
is no longer being used. This is visible during handover, where we still
receive a measurement report after the MS has switched to the new channel.
This leftover measurement report then attempts to trigger another handover,
which si bogus and will fail - and thus only consumes resources.
With the new LCHAN_S_ACTIVE state, we can check for this when processing
the measurement report.
We will need this for the actual handover algorithm implementation, as we will
only know the current BTS and the BCCH ARFCN of the strongest cell in the
measurement reports. Using this new function, we can resolve the matching
gsm_bts.
We use a 1024-bit-sized bitvec to generate the BA and neighbor frequency list.
This bitvec is still generated from the list of all BTS's inside the BSC, but
this patch is the first step to generalize this, i.e. generate arbitrary
neighbor lists.
With ip.access, in case of TCH/H, we have one RTP stream for each half-slot
(lchan), not just one per on-air timeslot. This is quite different from
a classic BTS where the TRAU frames of the two TCH/H channels would be
part of the same 16k sub-slot in a E1 timeslot.
Before this commit, OpenBSC used templates for the SYSTEM INFO
1, 2, 3, 4, 5 and 6 messages. Those templates were patched in
various places to reflect the network config like ARFCN.
Now, we actually generate those SI messages ourselves, using
values from the configuration file, and even calculating neighbor
cell lists.
All bts'es that you have configured in OpenBSC will end up in
the neighbor cell list - which should be more than sufficient for
the current small-single-site networks.
- Make sure that on runtime the Radio Carrier can be
locked and unlocked. The vty code calls into the
Abis NM to lock/unlock the channel and the state is
stored there.
- Make sure that on start the Radio Carries remains
offline and we are not starting it. On start the
radio carrier is either locked or unlocked. This means
the RSL will not connect until the RF is unlocked. It
will connect then. To see RSL bringup failures one
needs to parse the RSL nack message.
- When the TRX is locked on startup the RSL link will
only be established after it will be unlocked.
Both GSM 04.08 RR and GSM 08.58 RSL need the multirate config
in the channel modify. Place the config in the lchan, change
the gsm48 methods to not take the argument, change the RSL
implementation to make use of it with the right IE.
The other code should use the t(l)v_put routines as well but
were left untouched for now.
Keep track of which SAPIs have been established either by the
BTS (from the MS) or by us. This can be used by the on-waves
BSC code to figure out if a new request should be made.
Supporting GPRS means we have a number of additional OML objects to
deal with. We need to extend our gsm_bts structure to at least
include the nm_state for each of those objects.
Add support for 1900 nanoBTS by using unified bts_type
GSM_BTS_TYPE_NANOBTS for 900, 1800 and 1900 versions.
Reduce the nanoBTS enum values to one and derive the
version from the user supplied band. In the future we
might want to do auto band detection.
The configuration file needs to be changed to refer
to nanobts instead of nanobts900/nanobts1800.
Signed-off-by: Mike Haben <michael.haben@btinternet.com>
Signed-off-by: Holger Hans Peter Freyther <zecke@selfish.org>
The LAC can be 16bit of size. the generation of the LAI, struct
gsm_subsriber and the BSC<->MSC was already using it as a
16bit (short) value.
Change struct gsm_bts to parse 16bit and change the vty configuration
parsing code to deal with a short too.
Transfering the cell_identity from BSC to MSC is required for the
on-waves.com support. Allow to set the cell_identity in the cfg
file and patch the system information tables to set it.
This just adds the 04.08 and RSL bits for A5, but not the logic
for performing authentication.
The caller would first set lchan->encr and then call
gsm48_send_rr_ciph_mode(lchan), which encapsulates the 04.08
CIPHERING MODE COMMAND into a RSL ENCRYPTION COMMAND and sends it
to the BTS for execution + forwarding.
The channel allocator can be set in ascending or descending order.
Ascnending means we first try to allocate channels on TRX0, then TRX1, etc.
Descending means we first try to allocate cahnnels on TRXn, then n-1 down to 0.
we now have the full path from the MS into the database (SUBMIT), as well as
back from the database to the MS (DELIVER). The database gets correctly
updated once a SMS has been successfully delivered.
What's still missing is the periodic scan over all undelivered messages,
trying to deliver them to the respective MS. So far, you have to manually
trigger this on the telnet interface with 'sms send pending 1'
* we only need one piece of code to calculate rsl_ie_chan_mode from
our run-time data structures (gsm_lchan)
* add some more channel modes for TCH/H and data
* use enum's to make the compiler warn us about unhandled enum values
* make sure the caller determines the (signalling,speech,data) mode
Up until now, we only supported direct RTP streams between ip.access BTS.
With this commit, the user can specify '-P' to the command line to enable
a RTP/RTCP proxy inside OpenBSC. The nanoBTS will then send all their voice
data to OpenBSC, which will relay it to the respective destination BTS (which
can be the same BTS).
The default behaviour remains unchanged. Without '-P' on the command line,
RTP/RTCP is exchanged directly.
Since a transaction is associated to a gsm_subscriber, and the subsciber
is part of a network, we don't need to have a dedicated transaction->network
pointer.
This changeset factors out gsm_transaction as something independent
of call control in preparation to re-use the code from SMS. A
transaction is uniquely identified by either its callref, or by
a tuple of (transaction_id, protocol, subscriber).
Since a transaction is associated to a gsm_subscriber, and the subsciber
is part of a network, we don't need to have a dedicated transaction->network
pointer.
Holger Hans Peter Freyther
Harald Welte
Sylvain Munaut