The reason for this is quite simple: We want to make sure anyone
running a customized version of OpenBSC to operate a network will
have to release all custom modifiations to the source code.
OSX does not provide an endian.h, use the other header files that
should define/include what we need. Also check that the byteorder
define is available.
Bind a new port for the transcoder, forward data from the BTS
to the transcoder, and from the transcoder to the network. Leave
BTS-IN where it is, BTS-OUT can now be after the transcoding took
place. We send the data from the BTS RTP port.
This whole route will be guarded by the transcoder_ip and if it is
NULL (current default) it will not go through the transcoder.
Do not use the CI_UNUSED to decide if an endpoint is allocated
but introduce a new flag. This way only the CRCX and free_endp
play with the allocated field.
If we have found the BTS and we receive data on the RTCP port
from the IP of the BTS we will set our RTCP port and forward it
to the network and hope it will be useful.
For debugging it is useful to forward (tee) UDP packets to another
system and use gstreamer to inspect the rtp stream. This is untested
code and might contain bugs.... and of course only tap your own calls.
Once we have discovered the bts we will not accept data from
anything else. The call will drop if the BTS is changing the
ip address of the nat anyway.
Allow to switch to a dynamic port allocator and not reuse
the ports for a long time... This should help with a crazy
network sending two streams at the same time.
This allows a more strict check on the source of RTP messages
and we can more easily reject those. For the BTS without an ip
address we will also update the ip address.
We plan to have two different ports for the network and for the
BTS to avoid detecting the BTS and to dynamically allocate the
port to have old data not go to a new socket.
This code compares the UDP sequence numbers of two RTP messages
and guesses if packets are missing. It is guessing in two ways:
1.) by default the sequence number is 0, so on the first
value we ignore the jump... we might ignore a real issue
in case of a wrap around which is easily possible as the
sequence should be a random number.
2.) the UDP stream might have been reordered on the network
and we would see the jump...
In any case these two shortcomings are acceptable for the feature
that is meant to provide some basic analysis..
Harald Welte
Holger Hans Peter Freyther