Do not free the GSM Subscriber Connection when a channel is failing
or if a clear is requested, instead just give up _all_ the channels,
reset them to NULL and free the remaining channels.
When we reject the IMSI we do not have the msc_con set on the
SCCP connection, but we do have a remote_ref. So the nat_send_rlsd
will end up with a crash due the msc_con being zero. Fix the
crash by only sending a released to the MSC when the connection
is not local.
Add the code that is forwarding data, from and to the MSC, also
handling ping/pong timers and authentication. Hook it into the
osmo_bsc. The code is only compile tested and ported from the
on-waves/bsc-master branch.
The grace code will decide if a given connection is allowed to
be made or if it is going to be rejected. For active connections
it is going to send a USSD message.
Keep a back pointer to the rf struct inside the connection,
resolve the network through the back pointer. Also assume
that the RF is on. In case we start with RF locked, the policy
is on but we will not see any MS talking to us.
This way we avoid seeing many warnings that we will not forward
data to the MSC. For the con_local connections that is actually
the idea, we will not forward them to the MSC.
Attempt to disconnect the connection and make both sides happy
about this. Right now it only handles the LU and should be extended
to the CM Service Request.
Return early in case the IMSI was already checked, if not we need
to look at the connection and check if the message could contain a
imsi we want/need to filter.
Return -1 if the IMSI should be filtered, 0 if the IMSI could not
be checked and 1 if the IMSI was checked and allowed to pass. In
the future this will be used to inspect every message coming by.
Add some code to count TCH/H and TCH/F and also handle
the neci bit of the network. Our channel allocator will
allocate a TCH/F if we request a TCH/H but can not allocate it.
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.
Instead of throwing a huge pile of paging commands to the BTS
we will submit one paging command every half second. This way
we can have different messages between the paging commands.
This is done to avoid crashes of the nanoBTS when too much
paging messages are send.
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.
When the cell becomes visible we will be bombed with location
updating requests and to reduce the load on the network we should
assign as many channels for it as possible. During load peek it
is even more important than to have a spare voice channel and in
general the LU procedure is pretty fast.
Holger Hans Peter Freyther