ussd: Send USSD on call setup on MSC errors

Send an USSD message to the mobile station requesting a connection
for a call or a SMS when the link to the MSC is down or in the
grace period.

The messages can be set (and this feature activated) by setting
bsc/missing-msc-text resp. msc/bsc-grace-text via the vty.

The generation of both messages has been tested manually.

Ticket: OW#957
6 files changed
tree: 54d596cb3e32242d1dad87e555bfe2a8020eea6b
  1. debian/
  2. hlrsync/
  3. linux-kernel/
  4. openbsc/
  5. wireshark/
  6. README