sgsn/ctrl: Add ctrl interface, implement listing subscribers

Add the control interface with no hierachy right now and implement
the first command to list IMSI + Context Address of active sessions.
sgsn_cmd_handle could share more code with bsc variant.

Fixes: SYS#264, SYS#265
6 files changed
tree: 146d6a943d44c950ee10244691c01061624ae309
  1. debian/
  2. hlrsync/
  3. linux-kernel/
  4. openbsc/
  5. wireshark/
  6. README