osmux: Remember the allocated CID and make sure it is released

There appears to be a leak of CIDs:
 <000b> mgcp_osmux.c:544 All Osmux circuits are in use!

There are paths that a CID had been requested and never released
of the NAT. Remember the allocated CID inside the endpoint so it
can always be released. It is using a new variable as the behavior
for the NAT and MGCP MGW is different.

The allocated_cid must be signed so that we can assign outside
of the 0-255 range of it.

Fixes: OW#1493
5 files changed
tree: 520d1516c16692a778c0db8aabb49bcd330ed656
  1. debian/
  2. hlrsync/
  3. linux-kernel/
  4. openbsc/
  5. wireshark/
  6. .gitignore