gsm/sms: Rewrite of SMC process, extracted from OpenBSC

The SMC process is used to transfer RP frames. It is now extracted from
OpenBSC. It includes a real state machine now for easier debugging.

Written-by: Andreas Eversberg <jolly@eversberg.eu>
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
5 files changed