sgsn: Be more tolerant with state and SUSPEND/RESUME

Currently, when a BSSGP SUSPEND is received and the corresponding MM
context is already in the state GMM_REGISTERED_SUSPENDED, a
SUSPEND_NACK is returned which is not covered by GSM 08.18, 7.4.1.
The same goes for RESUME in the state GMM_REGISTERED_NORMAL.

This commit changes gprs_gmm_rx_suspend and gprs_gmm_rx_resume to not
complain (and thus answer a NACK) when the MM context is either in
GMM_REGISTERED_SUSPENDED or GMM_REGISTERED_NORMAL.

Note that GSM 08.18, 7.4.1 and 7.5.1 only mention to send an NACK if
the MS is not known. Even with this patch, the SGSN returns a NACK if
either the MS is unknown _or_ the MM context ist not in one of the
state GMM_REGISTERED_SUSPENDED and GMM_REGISTERED_NORMAL.

Sponsored-by: On-Waves ehf
1 file changed
tree: f0f1a7fb1023c26f1fb1f42afcc1e50e269f7591
  1. debian/
  2. hlrsync/
  3. linux-kernel/
  4. openbsc/
  5. wireshark/
  6. README