Move the conversion of GSM0808 timeslot and multiplex from
the bssap.c into the mgcp.h so it can be reused by multiple
users. The weird math comes from the mapping of the MSC...
When losing the SCCP connection make sure that we free all
endpoints. The disconnection of the BSC should already make
sure they are closed but this makes sure everything is
properly reset.
For the nat we will have NAT and MGCP in the same process
and this commit starts with that. We are linking in the MGCP
code and one can embed MGCP config snippets...
Make the source address mandantory and complain about
complain when it is missing. The address is mandantory
as it needs to be put into the MGCP messages...
* Return the SCCP connection. This will be needed to store the
assigned timeslot in there.
* Update code to work with this change
* This uncovered a bug in the CC handling, at the time the BSC was
passed it was still a null pointer and the code would have failed.
Moving it here means we can more easily test this code, there is one
behaviour change with the code that we only support paging messages
with one LAC and will silently ignore the others.
This test case tests connectiont tracking by sending
a CR, getting a CC, sending a DTAP, receiving a DTAP,
receiving a RLSD, sending a RLC. It verifies that the
messages are properly patched specially the references
at the BSC.
When sending a message to the MSC in the case of DT1
messages we only have the address of the MSC, so we
need to go with that, otherwise (e.g. in case of a CR, RLC)
we do have the source address and need to patch it.
When forwarding a message to the BSC we do receive
a msg that should contain the patched address, we need
to unpatch it...
On a CC message we will need to remeber where the source local
reference of the network belonged so we can properly identify
the connection when receiving UDT messages.
Instead of simply exiting the application we will handle it by
giving up all SCCP connections, once we have the MSC back we will
send a GSM 08.08 reset message, and we will free all resources
related to these connections. This includes the primary and secondary
lchan of these connections.
While we are not connected to the MSC we will handle each message
that would open a SCCP connection by giving up the lchan. This has
only been compile tested and will need to be manually tested during
a test session.
This also highlights a DoS that could be used against OpenBSC
by setting up a lchan but never send any GSM L3 message. We will have
to fix that at some point.
When we disconnect from the MSC handle it by pushing the problem
to our connected clients. We will simply close all connections,
reject all new BSC connections and attempt to reconnect to the MSC.
Create a BSC<->MSC interface and use it for the BSC MSC IP and the
BSC NAT to reduce code duplication on handling reconnects to the MSC
and cleaning up the local state. The code is only partially tested
and will contain bugs. Currently both the BSC and the NAT will just
exit on connection loss and this way have the current behavior.
The latency of setting up of the TCP connection can be quite high,
it is better to connect in a non blocking way. This code is working
by setting the socket nonblocking and temporarily replacing the
bfd callback with the connect handling.
Once the OS has connected our socket we switch back to normal operation.
In case we disconnect with some pending operations we will need to
signal the MSC that something is wrong. This could be by sending a
RLSD directly, or a clear command. Another part of the fix is to
respond with a RLC on unknown RLSD messages.
